Accelerator Physics, Astrophysics, Cosmology,
Particle Physics and Nuclear Physics
POSTER: AS-01
Amirnezam. Amiri* 1, Fereshteh. Memarian 1, Sara. Charmchi 1,
Meysam. Honari-Jafarpour 1, Amir. Hasanzade 1,2
1
TheInternationalOccultationTimingAssociation-MiddleEast
Section(IOTA-ME),Iran
2
UniversityofTehran,Iran
amirnezamamiri@gmail.com
Observation and data analysis of the newly discovered Delta
Scuti variable star: GSC1489-0914
Thedifferentialtime-seriesCCDphotometryhasbeencarriedout
during2013forthehigh-amplitudeDelta-ScutistarGSC1489-0914.
Based upon our data and others available in the literature a
comprehensive analysis has been conducted to investigate the
physical parameters of the star including luminosity, distance,
mass, radius, surface gravity etc. The main frequency and new
ephemeriscalculationindicatesoscillatorybehavior.Notethatthis
type of variables are standard candles so these analysis would
guidetoitsharmonicsandpulsationmodesinthefuture.
POSTER: AS-02
Qing-Yu Cai
ChineseAcademyofSciences,China
qycai@wipm.ac.cn
Recovering Lost Information in Hawking Radiation
Abstracts | Posters
Inbothclassicalandquantumworld,informationcannot appear or
disappear. This fundamental principle, however, is questioned for
a black hole, by the acclaimed “information loss paradox”. Based
on the conservation laws of energy, charge, and angular
momentum,werecentlyshowthetotalinformationencoded in the
correlationsamongHawkingradiationsequalsexactlytothesame
amount previously considered lost, assuming the non-thermal
spectrumofParikhandWilczek.Thustheinformationlossparadox
canbefalsifiedthroughexperimentsbydetectingcorrelations,for
instance, through measuring the co-variances of Hawking
radiations from black holes, such as the manmade ones
speculated to appear in LHC experiments. The affirmation of
information conservation in Hawking radiation will shine new light
on theunificationofgravitywithquantummechanics.
POSTER: AS-05
Paul Barton1, Ankur Dhar1, James Loach* 2, Alan Poon1
1
LawrenceBerkeleyNationalLaboratory,USA
2
ShanghaiJiaoTongUniversity,China
james.loach@gmail.com
A Low-Background Temperature Sensor
Critical to experiments searching for neutrinoless double-beta
decay or the interactions of WIMP dark matter is the control of
radioactive backgrounds. It is crucial to minimize the
concentrations of radioisotopes in all the components of an
experiment, from the large homogeneous masses that comprise
the active regions to the small components such as sensors and
cablesthatareneededtoreadoutthesignals.Thecomplexityof
itemsinthislatterclass,thesmallcomponents,oftenmakesthem
very difficult to make radio-pure and thus gives them an
importanceoutofproportiontotheirmass.Thisworkisaproofof
conceptstudyofatechnologythatpromisestoreduceradioactive
contaminationinaclassofsmallcomponents- electroniccircuitsthat are ubiquitous and notorious sources of background events.
Resistive temperature sensors are fabricated onfilms of a vapordeposited plastic called parylene using techniques that are
generalizabletoalargeclassofelectroniccircuits.Thesesensors
are demonstrated to function as expected, to do so reliably and
robustly,andtobehighly radio-pure.
POSTER: AS-06
Pisin Chen, Yi-Shiou Duh, Lance Labun, and Yao-Yu Lin *
NationalTaiwanUniversity,Taiwan
joshualin24@gmail.com
Gravitational Slingshot as a Solution to Cusp-Core Problem
In the Λ cold dark matter model, N-body simulation predict a
power-law-like distribution in the inner regions on the galaxies,
which is in conflict with observational evidence suggesting
approximately constant dark matter density distribution. This is
cusp-core problem. Here we study gravitational slingshot as an
accelerationmechanismfordarkmatterparticlespassingneartoa
massive object like a star.We calculatethe average energy gain
due to slingshot, then we construct a one-dimensional model to
show how the dark matter are affected. Our study shows
preferentialincreasesenergyofdarkmatterinregionsofhighstar
numberdensityatgalaxiescenters,whichflattensthedarkmatter
distributionfromaoriginalcuspprofile.
POSTER: AS-07
POSTER: AS-03
Yu Chen*, Edward Teo
NationalUniversityofSingapore,Singapore
chern.yu@gmail.com
A class of vacuum solutions in four dimensions
We discuss a new five-parameter class of Ricci-flat solutions in
fourdimensions.Itcanbeconsideredasaone-parameterfamilyof
asymptotically locally flat interpolations between the Ricc-flat
Plebanski-Demianski and the triple-collinearly-centered GibbonsHawkingsolutions.
POSTER: AS-04
Michael R.R. Good
NanyangTechnologicalUniversity,Singapore
mgood@ntu.edu.sg
Circular Cooling
C. Meng*, J.Y. Tang, A. Lombardi, R. Garoby, F. Gerigk, S. L.
Pei, F. Yan, Z. H. Li
ChineseAcademyofSciences,China
mengc@ihep.ac.cn
High power proton Linac designs with non-equipartitioning
method
Superconductinglinearacceleratoristhetendencyinlinacdesign
with the development of superconducting technology. Period
phase advance less than 90 degree and equipartitioning design,
verifiedbytheoryandexperiment,areveryimportantprinciplesin
linac.Usually,thelongitudinalemittanceisbiggerthantransverse
emittance,sothetransversephaseadvanceisbiggeraccordingto
equipartitioning principle. However, the accelerating gradient of
superconducting cavity is increasing with the development, the
phase advance is becoming the limit to reduce the cost and
accelerationefficiency.Inthispaperwepresentthedesignmethod
that keepingthe longitudinal phase advance as large as possible
but smaller than 90 degree to maximize the use of the available
accelerating gradient. Even though this method cannot satisfied
theequipartitioningcondition,wecanalsogetverygooddynamic
results. In this paper the SPL and C-ADS main linac design and
simulationresultswiththismethodwillbepresent.
Angular momentum lowers the temperature of a black hole. A
suggestedexplanationisthatcircularaccelerationremovesheat.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 73
POSTER: AS-08
R. Sambasivam
UrumuDhanalakshmiCollege,India
sambasvm@gmail.com
Nuclear EMC effect in Nachtmann variable by a statistical
model
Even after three decades of discovery of nuclear EMC effect,
where high energy muons at CERN revealed this remarkable
phenomenon,recentdevelopmentsinunderstandingtheinfluence
of the nucleus on deep-inelasticstructurefunctions are reviewed.
ThestandardBjorkenvariableiscommonlyusedinthediscussion
of DIS processes. If one retains M2/Q2 in the kinematics, then
another variable introduced by Nachtmann seems to be more
appropriate to describe DIS processes. Many phenomenological
models tried to account for this effect. A statistical based model
knownasThermodynamicalBagModel(TBM)thatexplainsstatic
anddynamicpropertiesofnucleons,isusedhereasafunctionof
Nachtmann variable to account for nuclear EMC effect.
Convolution model that convolutes momentum and energy
distribution of bound nucleons with single nucleon structure
functionisusedtostudyvariousnucleilikeBe9,Al27,Ca40,Fe56,
Cu63,Ag108,andAu197.ThoughherenuclearbindingandFermi
motion play thekey role and explain the EMC effect inthisinitial
attempt, further studies are also required to enter deep into DIS
processes.
POSTER: AS-09
Ye Zou, Jingyu Tang*
ChineseAcademyofSciences,China
tangjy@ihep.ac.cn
Resonant Slow Extraction in Synchrotrons by Using AntiSymmetric Sextupole Fields
This presentation proposes a novel method for resonant slow
extraction in synchrotrons by using special anti-symmetric
sextupole field, which can be produced by a special magnet
structureandwasproposedearlier.Themethodhasthepotential
in applications asking for very stable slow extraction from
synchrotrons and in the halo collimation of very large machines.
Ourstudiesshowthattheslowextractionbyusinganti-symmetric
sextupole field has some advantages compared to the normal
sextupole field which is used in the usual third-order resonant
extraction method. One of them is that it can work at a more
distanttunefromtheresonance,sothatitcanweakensignificantly
theproblemoftheintensityvariationoftheextractedbeammainly
caused by the ripples of magnet supplies. The studies by both
Hamiltoniantheoryandnumericalsimulationsshowthatthestable
regionbyanti-symmetricsextupolefieldismuchsmallerandflatter
attheproximityofthehalf-resonance,andtheparticlesoutsidethe
region will be driven out in two possible directions in quite short
transit time but with spiral steps similar as in the third-order
resonance extraction. By gradually increasing the field strength,
thebeamcanbeextractedinamorehomogeneousintensitythan
the usual third-order resonant method, in the means of both
smallerintensityvariationandspikein thebeginningspill.
POSTER: AS-10
Wong Whye Khuin Nicholas
NationalUniversityofSingapore,Singapore
wwk.nic@gmail.com
Fluctuation about Cosmological Instantons
We studied the bounce solutions of self-interacting scalar fields
coupled with gravity using a semi-classical approach. Our data
suggests that bounce solutions not only have a minimum barrier
curvature, but also a maximum barrier curvature. In addition, we
propose a new class of bounce solutions, where the scalar field
behaves like the Coleman-De Luccia bounce solutions, but the
scale factor does not vanish at any finite Euclidean time. Unlike
Coleman-De Luccia bounce solutions or oscillating bounce
solutions, this cannot be considered a subset of the Hawking-
74 | The 8th OCPA International Conference on Physics Education and Frontier Physics
Turok solution. However, like the Coleman-De Luccia bounce
solutions,thequantumfluctuationaboutthisnewsolutionhasonly
onenegativemode,suggestingthatitmayalsobeassociatedwith
quantumtunnelling.
AMO and Quantum Computing
POSTER: AMO-01
POSTER: AS-11
Chi Xiong
NanyangTechnologicalUniversity,Singapore
xiongchi@ntu.edu.sg
On QCD String and Its Applications
We apply an anomaly inflow mechanism to the study of QCD
strings/flux tubes, quark creation,chiralmagnetic effect, U(1) and
strongCPproblemsviatheCho-Faddeev-Niemidecompositionof
the gauge potential. A phenomenological description of
chromoelectric flux tubes is obtained by studying a gauged
Nambu-Jona-Lasinio effective Lagrangian, derived from the
original QCD Lagrangian. QCD strings may induce quantum
vortices in the quark condensate. Chiral quark zero modes are
then trapped in each vortex, which lead to a two-dimensional
gaugeanomaly.TocancelitaneffectiveChern-Simonscouplingis
needed, and hence a topological charge density term naturally
emerges. This term is a coupling between a superflow of the
phase of the quark condensate and the Chern-Simons current.
The usual theta-parameter is replaced by the phase of the quark
condensate, which becomes nontrivial due to the existence of
topological defects such as vortices. This new formulation can
address the U(1) problem in a similar way as in the theta-world
and avoid the strong CP problem as the new topological charge
term is a derivative coupling. Some interesting phenomenological
applications like chiralmagnetic effects and the Josephson effect
arediscussed.
References:
1)arXiv:1310.8657[hep-th]
2)arXiv:1302.7312[hep-th](Phys.Rev.D88(2013)025042)
POSTER: AS-12
LiTao Yang*, Qian Yue
TsinghuaUniversity,China
Pauli127@163.com
Limits on light WIMPs from the CDEX-1 experiment at the
China Jinping Underground Laboratory
We report results of a search for light Dark Matter WIMPs with
CDEX-1experimentattheChinaJinpingUndergroundLaboratory,
based on 53.9 kg-days of data from a p-type point-contact
germanium detector enclosed by a NaI(Tl) crystal scintillator as
anti-Compton detector. Both the event rate and spectrum above
analysisthresholdof475eVeeareconsistentwiththeunderstood
backgroundmodel.
An order of magnitude improvement in the sensitivities of spinindependent elastic cross-section over our previous results is
achieved, and this is the best sensitivity of searching WIMPs
achieved by PCGe detectors in the world until now. Part of the
allowed regions at WIMP mass of 6-20 GeV are probed and
excluded.
Budi Mulyanti1*, Lilik Hasanah1, Tommi Hariyadi1, Rischa
Novitasari1, P.S. Menon2, S.Saari2, Arjuni. B. Pantjawati1, Heru
Yuwono3
1
UniversityPendidikanIndonesia,Indonesia
2
UniversitiKebangsaanMalaysia
3
ArsariGroup,Indonesia
b_mulyanti@yahoo.com
The Influence of Q-factor to Resonant Wavelength Shift
of Si-based Microring Resonators
Microring resonators (MRRs) as a compact and multi-functioned
device has become one of the potential components in silicon
photonicsintegratedcircuitsdesign.Inthispaper,theinfluenceof
qualityfactor(Q-factor)totheresonantwavelengthshiftofMRRs
is presented. The calculation is carried out using semi-numerical
method for different value of glucose concentration. The
parameters used in the calculation including incident wavelength,
ring radii of circular waveguide, gap sizes between circular and
straight waveguides, the dimension of both waveguides, and
refractiveindex of silicon, SiO2 and air. The results show that Qfactor slightly affectsthe resonant wavelength shift.The resonant
wavelength shift depends on the glucose concentration. The
increase of the glucose concentration causes the increase of the
resonantwavelengthshift.
Second,theeruptionwithoutprecededbyanimpulsive explosion.
The explosion is related to low-frequency events (LF).
Manifestationsoferuptionseenonthesurfaceofthecraterafew
seconds after the start of the seismic recordings. This indicates
thattheexplosiveeruptionatLokonprecededbytheexpansionof
agaspocketorrisingmagmathathasbeenfragmentedinconduit
priortoeruption.
POSTER: AMO-04
Dr. Eng. Alamta Singarimbun
InstitutTeknologiBandung,Indonesia
alamta@fi.itb.ac.id
Numerical Simulation of Fluid Flow in Geothermal Reservoir
by using Finite Difference Method
Geothermal energy is well known as a renewable and clean
energy. The first step to predict geothermal potential energy can
be estimated by modeling, among others physical and numerical
simulation.Inthis research, the geothermal reservoir is simulated
by using different parameters by some parameters such as
permeability, porosity and thermal conductivity. Mathematical
modelingisconstructedbasedonDarcy'slaw,massbalanceand
energy balance. Then the model is calculated by using finite
differencemethod.Resultsofthecalculationareobtainedinform
of distribution of temperature, pressure, enthalpy and direction of
fluidflow.
POSTER: AMO-05
POSTER: AMO-02
Kin Sung Chan
NanyangTechnologicalUniversity,Singapore
ch0085ng@e.ntu.edu.sg
Adsorbate Electric Fields on a Cryogenic Atom Chip
We investigate the behaviour of electric fields originating from
adsorbatesdepositedonacryogenicatomchipasitiscooledfrom
room temperature to cryogenic temperature. Using Rydberg
electromagnetically induced transparency we measure the field
strengthversusdistancefroma1mmsquareofYBCOpatterned
onto a YSZ chip substrate.We find a localized and stable dipole
field at room temperature and attribute it to a saturated layer of
chemicallyadsorbedrubidiumatomsontheYBCO.Asthechipis
cooled towards 83 K we observe a change in sign of the electric
fieldaswellasatransitionfromalocalizedtoadelocalizeddipole
density.Werelatethesechangestotheonsetofphysisorptionon
thechipsurfacewhenthevanderWaalsattractionovercomes the
thermal desorption mechanisms. Our findings suggest that,
throughcarefulselectionofsubstratematerials,itmaybepossible
toreducetheelectricfieldscausedbyatomicadsorptiononchips,
opening up experiments to controlled Rydberg-surface coupling
schemes.
POSTER: AMO-03
Dolfie Pandara*, Lilik Hendrajaya, Alamta Singarimbun
BandungInstituteofTechnology,Indonesia
dpandara@yahoo.com
Characteristic of Volcanic Explosions on Lokon Volcano at 910 September 2013
Lokon is one of the most active volcanoes in Indonesia and the
behavior of its eruptions have explosive properties. Seismic
signalscan representthe explosivity of eruptions.Investigation of
theseismicsignalgeneratedfromvolcanicexplosionscanbeused
tocharacterizethetypeandsourceoftheeruptionmechanism.In
this study, we investigated the eruption that occurred on 9 to 10
September 2013. Based on seismic analysis, explosive eruptions
that occur in Lokon can be classified into two types. First, an
eruption is preceded by an impulsive explosion. The explosion is
relatedtothelongperiodofprecursoreventsandvolcanictremor
that appeared a few hours or a few minutes before the eruption.
Dra. Fatchatul Baiyinah
BATAN,Indonesia
Fatcha2009@yahoo.com
Nuclear Reactor in Indonesia
The International Atomic Agency formed since 1957, after that
Indonesia form LTA ( LembagaTenaga Atom), which the
Indonesian health minister Mr. DR. G.A Siwabessy as a leader.
The first nuclear reactor in Indonesia is TRIGA MARK II reactor,
and The General Atomic in San Diego California as supplier. On
1964 LTA change the name to BadanTenaga Atom Nasional
(BATAN). The first nuclear reactor in Indonesia TRIGAMARK II
reactorsigned by Ir.Soekarno on February 20th 1965 with name
PRAB-BATAN and operated on power 250 kilowatt. The activity
are for research and vocational training, Research and
development for pure material, radioisatopes and labelled
compound, instrumentations and radiometric analyze techniques,
andmonitoringforsafetyonradiationandenvironment.
The first Nuclear medicine in Indonesia developed in Bandung
nuclearfacility.Nowthisactivityheldinsomehospital.Tosupport
the research and development activity, nuclear Bandung area
support by some facility there are Triga Mark II reactor with 250
Kw power on 1965, and upgraded to 1000Kw on 1971, and then
upgraded to 2000Kw on 2000. Other facility here are physics,
chemistry and biology laboratory, isotopes productions and
labelledcompound.
Afterthatsomenuclearfacilityhadbuilt.
- Pasar Jum‟at nuclear area Jakarta, built on 1966 on 20 ha area.
Their facility are Gamma irradiator (ɣ) 60CO, electron beam
machine, uranium process laboratorium, chemistry and biology
laboratoriumprocessandhydrology,educationandtrainingfacility,
- NuclearreactorinYogyakartahadbuilton1974on8.5haarea,
In this area had Kartini reactor with 100Kw power, subkritic
devices, pure material research laboratory, accelerator, physics
and nuclear chemistry laboratory, work safety and health facility,
library,andlaboratoryforeducationfacility.
- NuclearreactorandlaboratoryinSerponghadbuilton1992on
25 ha area, in PUSPIPTEK (The centre of research and
developmentforsciencesandtechnology)Serpong.
Now,westudyingthefeasibilityofthesafetymarginsforplatefuel
element in Bandung reactor. The cooling water flow rate was
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 75
variatedon36m3/h,40m3/hand44m3/hforanypowerthatare
500kilowatts,638kilowatts,750kilowatts,and1000kilowatts.
Summary:
For stability graphic decrease faster on flow rate 36m3/hthan 44
m3/h
For ONB graphic the sama shape but lower on flow rate 36m3/h
than44m3/h
ForBURNOUTgraphictheflowrategoingdownfasteron44m3/h
than36m3/h
anidealsystemtostudyandsimulatequantummay-bodyphysics.
By exciting ground-state atoms in an optical lattice to Rydberg
states, we can realize a lattice of Rydberg atoms which is
promising to reach a system of strong correlation, strong
interaction, and low temperature. In this poster, we present the
currentstatusofourexperiment,thenear-futuregoalsofdetecting
and probing Rydberg atoms via electromagnetically induced
transparency, and our work towards the realization of a lattice of
Rydbergatoms.
POSTER: AMO-09
POSTER: AMO-06
Wei Feng
BeijingComputationalScienceResearchCenter,China
fengwei@csrc.ac.cn
Effect of Atomic Distribution on Cooperative Spontaneous
Emission
Superradianceisawell-knowncooperativephenomenonthatwas
firstpredictedintheorybyDickein1954.Anintriguingconclusion
is thatwhenNidenticalatomsinthelimitofasmalldimensionare
uniformlyexcitedbyasinglephoton,thedecayrateofthesystem
is N times that of the isolated atom. Dicke called this „„the greatest
radiation anomaly‟‟ of superradiance. However, for thepurposeof
simplifying the discussion of this many-body problem, Dicke and
subsequent researchers all ignored the details of N-atom exact
locations and taken an average distance between the atoms.
Recently, we have investigated the influence of the atomic
distribution on the cooperative spontaneous emission. First, we
select the simplest model of three identical atoms where we can
obtaintheanalyticsolutionsofthedecayratesandLambshifts.It
is shown that the atomic configuration (distribution) has big
influence on superradiance of the system. To obtain strong
superradiance requires not only the distances among the three
atoms much shorter than the radiation wavelength, but also the
symmetrical distribution. Next, we extend the research to the
realisticmulti-atommodelbynumericalcalculation,wherewefind
the similar conclusion that the uniformly atomic distribution is a
necessary condition for approaching the limit of Dicke
superradiance.
POSTER: AMO-07
Frederic Leroux*, David Wilkowski
NationalUniversityofSingapore,Singapore
a0094305@nus.edu.sg
Geometrical Adiabatic Qubit and Artificial Magnetism in a
Four-level Tripod
Afour-leveltripodsystemdrivencontinuouslybythreelasershas
apairofdarkstateswithzeroenergywhichcanbeusedtoencode
a single qubit. We show that by tuning the phases of two lasers
adiabatically the state vector of the atom stays within the dark
states eigenspace.Inthis way, we can define a U(2) geometrical
gate for this qubit. An optically synthesized non-Abelian Gauge
potential connected to this geometrical gate emerges.
We will use magnetic sublevels of one of the hyperfine state of
Strontium87forthistripodconfiguration.Weexpectthedynamics
of these neutral atoms in this artificial Gauge field to mimic the
actionofakindofLorentzforce.
POSTER: AMO-08
Jingshan Han, Thibault Vogt, Ruixiang Guo, Wenhui Li
National UniversityofSingapore,Singapore
A0095136@nus.edu.sg
Ying-Yen Liao
NationalUniversityofKaohsiung,Taiwan
yyliao@nuk.edu.tw
Entanglement of Horizontally Adsorbed Polar Molecules in
Electric Felds
We investigate entanglement of two horizontally adsorbed polar
molecules in a static electric field. A conical well with an
asymmetric structure is used to capture the hindered rotation of
adsorbed molecules. Numerical results demonstrate that the
electric field strongly influences the rotational properties. Due to
the confinement effect, the field-dependent energy spectrum
shows two anticrossing features in the ground state. We employ
the concurrence to measure the degree of entanglement. The
concurrenceislocallyincreasedatzerotemperature.Bytuningthe
hindrance angle, the concurrence further displays two features
with distinct tendencies. The magnitude of concurrence is also
loweredwithatemperatureincrease,dependingontheproperties
oftheanticrossings.
POSTER: AMO-10
M.S. Pramod, Tao Yang, Kanhaiya Pandey, Massimo Giudici,
David Wilkowski
NationalUniversityofSingapore,Singapore
cqtpms@nus.edu.sg
Selective Injection Locking of a Multi-mode Semiconductor
Laser to a Multi-frequency Reference Beam
POSTER: AMO-11
S. Seshadri* and R. Sambasivam
BharathidasenUniversity,India
ssudc14@gmail.com
Scaled Quantum Chemical Calculations and FTIR, FT-Raman
Spectral Analysis of Indole-2,3-dione
ThesolidphaseFTIRandFT-RamanspectraofIndole-2,3-dione
(IDE)havebeenrecordedintheregions4000-400cm-1and3500100cm-1respectively.Thespectrumwereinterpretedwiththeaid
ofnormalcoordinateanalysisfollowingafullstructureoptimization
andforcefieldcalculationsbasedonthedensityfunctionaltheory
(DFT) using the standard B3LYP/6-31G* method and basis set
combinations. The DFT force field transformed to natural internal
coordinates was corrected by a well-establishment set of scale
factors that were found to be transferable to the title compound.
The IR and Raman spectra were predicted theoretically and
comparedwiththeexperimentalspectra.
Ju-Kui Xue
NorthwestNormalUniversity,China
xuejk@nwnu.edu.cn
Selective coherent spin transportation in a spin-orbit coupled
bosonic junction
We theoretically proposed a scheme for realizing selective
coherent spin transportation in spin-orbit coupled bosonic gas
trapped in a symmetric double-well by fast modulation of the
energy level unbalance between the two wells. The modulation
can be tunedinsuch a way thatan arbitrarily, a priori prescribed
spin type (singlespin, or aspin-pair with opposite spins) and the
number of these spin bosons with or without spin-flipping are
allowedtotunnel.Furthermore,prescribedsuperexchangeofspin
bosons is also presented. This engineering provides a possible
meansforspincontrol,accuratecountingorefficientfilteringofthe
numberofspins.
POSTER: AMO-12
Yong-Hui Zhang, Shi-Qi Tong, Dong Yin, Li-Yan Yang, TingYun Shi*
ChineseAcademyofSciences,China
tyshi@wipm.ac.cn
Bethe-logarithm Calculation for Hydrogen and Helium Atoms
Using B-spline Basis-set Method
It is known that in the leading-order radiative contribution to the
binding energy of atomic systems the most complicated quantity
for numerical evaluation is the Bethe logarithm [1]. Recently, a
method based on the B-spline basis set is developed which
significantly simplifies the Bethe-logarithm calculations for the
hydrogen atom. This method can not only calculate the Bethe
logarithms of low-lying states to high precision using relatively
small basis set, but also calculate the high-lying Rydberg states
efficiently[2].InthisConference,wewouldpresentournewBethelogarithm calculation for hydrogen in the length and the velocity
gauges. This represents the first successful attempt to calculate
Bethe-logarithms of hydrogen atom in the length and velocity
gauges. Furthermore, we would also present preliminary Bethelogarithmresultsforlow-lyingstatesofhelium.
Injection locking is a well-known and commonly used method for
coherentlightamplification.Usuallyinjectionlockingisobtainedon
a single-modelaserinjectedbyasingle-frequencyseedingbeam.
References:
In this work we show that selective injection locking of a singlefrequency may also be achieved on a multimode semiconductor
laserinjectedbyamulti-frequencyseedingbeam,iftheslavelaser
provides sufficient frequency filtering. This selective injection
locking condition depends critically on the frequency detuning
between the free-running slave emission frequency and each
injectedfrequencycomponent.
2) Y. B. Tang Z.X. ZHong, C. B. Li, H. X. Qiao, T. Y. Shi, Phys.
Rev.A87,022510(2013)
Stable selective injection locking to a set of three seeding
components separated by 1.2 GHz is obtained. This system
provides an amplification up to 37 dB of each component. This
resultsuggeststhat,usingdistinctslavelasersforeachfrequency
line,asetofmutuallycoherenthigh-powerradiationmodescanbe
tunedintheGHzfrequencydomain.
POSTER: AMO-14
POSTER: AMO-15
C.C. Kwong, Tao Yang*, M. S. Pramod, K. Pandey, D. Deland,
R. Pierrat, D. Wilkowski
1.)NanyangTechnologicalUniversity,Singapore
2.)NationalUniversityofSingapore,Singapore
3.)LaboratoireKastlerBrossel,France
4.)InstitutLangevin,ESPCIParisTech,France
5.)InstitutNon,LinéairedeNice,UniversitédeNiceSophiaAntipolis,France
tyang@nus.edu.sg
Coherent Forward Scattering Through an Ultracold Sr Atomic
Cloud
The transient coherent transmission of light through an optical
thick atomic medium is investigated experimentally. A high flux
source for ultra-cold Strontium atoms is constructed as the
researchobject.Whenaresonantlaserissentontheatomiccloud,
theabruptextinctionofthelaseremitsacoherentflashinforward
direction.Thepeakintensityoftheforwardscatteringisobserved
morethan3timesoftheincidentsamplitude.
1)V.I.Korobov,Phys.Rev.A85,042514(2012)
POSTER: AMO-13
Thi Ha Kyaw*1, Ying Li2, Leong Chuan Kwek1,3
1
NationalUniversityofSingapore,Singapore
2
UniversityofOxford,UnitedKingdom
3
NanyangTechnologicalUniversity,Singapore
thihakyaw@nus.edu.sg
Measurement-based Quantum Computation with Two-body
Qubits via Adiabatic Evolution
A cluster state cannot be a unique ground state of a two-body
interactingHamiltonian.Here,weproposethecreationofacluster
stateoflogicalqubitsencodedinspin-1/2particlesbyadiabatically
weakening two-body interactions. The proposal is valid for any
spatial dimensional cluster states. Errors induced by thermal
fluctuations and adiabatic evolution within finite time can be
eliminatedensuringfault-tolerantquantumcomputingschemes.
Towards a Lattice of Rydberg Atoms
Rydberg atoms are highly excited atoms, having large dipole
momentandhighpolarizability,whichresultinstrongdipole-dipole
interactions between atoms.Thismakes a gas of Rydberg atoms
76 | The 8th OCPA International Conference on Physics Education and Frontier Physics
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 77
Biophysics, Chemical Physics and Soft
Condensed Matter
POSTER: BC-01
Artem K. Efremov 1,2,*, Yuanyuan Qu 1,2,3, Hugo Maruyama 4, Ci
J. Lim 1,2,5, Kunio Takeyasu 4, and Jie Yan 1,2,3,5
1
MechanobiologyInstitute,NationalUniversityofSingapore,
Singapore
2
Centre forBioimagingSciences,NationalUniversityofSingapore,
Singapore
3
DepartmentofPhysics,NationalUniversityofSingapore,
Singapore
4
LaboratoryofPlasmaMembraneandNuclearSignaling,
GraduateSchoolofBiostudies,KyotoUniversity,Japan
5
NUSGraduateschoolforIntegrativeSciencesandEngineering,
Singapore
mbiay@nus.edu.sg
Global repressor protein, TK0471, from Thermococcus
kodakarensis forms a rigid nucleoprotein filament on GC-rich
dsDNA regions in a K+-dependent manner, competing with
histones and supressing DNA supercoiling.
ArchitecturalDNAproteinsinlivingcellsplayaveryimportantrole
inthegenomicDNAstructuralorganizationaswellasinregulation
of the genes' accessibility to transcriptional protein machinery.
While the role of architectural proteins in the chromosomal DNA
shaping was intensively investigated in previous experiments,
there is still a large gap in our knowledge about how the higher
order chromatin re-organization driven by these proteins induces
switching between different global gene expression patterns in
responsetoenvironmentalchanges.StudiesofDNAarchitectural
proteinsinsimpleeuryarchaeaorganismsatmolecularandcellular
levels may not only reveal interesting information about the
historical origin of epigenetic regulation in the earliest livingcells,
but also may provide a deeper understanding of more advanced
regulatory mechanisms taking place inside nuclei of eukaryotic
cells,whichhavequitesimilarDNAproteinmachinery.
InthisworkweusedacombinationofAFMimagingandmagnetic
tweezers single-DNA manipulation experiments in order to
systematicallystudyphysicochemicalpropertiesofTK0471protein
– oneofthemostabundantDNAarchitecturalproteinsinvolvedin
the global gene expression regulation in Thermococcus
kodakarensis euryarchaeal cells. We show that TK0471
preferentially interacts with G/C-rich regions of the genomic DNA
in vivo and strongly binds to dsDNAs with large positive
cooperativity in a potassium ions-dependent manner in vitro,
resulting in formation of rigid nucleoprotein filaments. Since our
analysis also suggests that archaeal histones from T.
kodakarensishaveaverysimilarG/C-preferenceinvivowepredict
that these two abundant DNA architectural proteins may be
involvedintodirectcompetitionforDNA-bindingsitesinlivingcells,
resultinginhighlydynamicorganizationofthegenomicDNA.This
hypothesis is supported by our observation of TK0471-histones
mutualocclusionforDNAbindinginsingle-moleculeexperiments.
Finally, it was found that a nucleoprotein filament formed by
TK0471resistsdsDNAfoldingduringitspositivesupercoilingand
promotes dsDNA melting during its negative supercoiling. Based
on these results we propose a simple model of the functioning
mechanism of TK0471 as an architectural and global gene
transcription regulatory protein, which can be further tested in
futurecellexperiments.
POSTER: BC-02
Che Azurahanim Che Abdullah*, R.P.L Sear
1)UniversitiPutraMalaysia,Malaysia
2)UniversityofSurrey,UnitedKingdom
azurahanim@upm.edu.my
Carbon Nanomaterials as Drug Transporter for Cancer
Therapy
Thereisavigorousandgrowingresearcheffortdevelopingcarbon
nanotubes (CNTs) for medical applications. It is now known that
nanocompositesofSingleWallNanotubes(SWNTs)canbeused
to deliver anti-cancerdrugstocells.1Also,SWNTsareefficient at
78 | The 8th OCPA International Conference on Physics Education and Frontier Physics
convertingnearinfrared(NIR)lighttoheat,andcandosoinacell,
and so cancer cells can be targeted for destruction by NIR
radiation,oncethecellshavetakenupSWNTs.SWNTsarehighly
insoluble in water, but can be functionalized via physical or
covalent attachment of solubilizing molecules and drugs of
interest.Oncethisisdone,theyarereadilytakenupbycells.2We
foundevidencethatourCNTnanocompositeswerefoundtoenter
cells via endocytosis (the mechanism cells use to take up
nutrients);thisagreeswithearlierworkbyDaiandcoworkers.2,3
Herein,weperformsystematicstudyoftheinternalization,delivery
and subcellular localization and possible adverse effects of
SWNTs dispersed in culture media and SWNTs wrapped with
different fluorescently labelled peptide (FLP-SWNTs) on Chinese
hamster ovary (CHO)cells andSWNTs attached with anti-cancer
drug on two common cancerous cell lines, human epithelial
carcinomacellline(HeLa)andcolorectalcancercelllines(WiDr).
POSTER: BC-03
1
1,
2,
Jin Chen *, Shimin Le Walter J. Chazin and Jie Yan
1
NationalUniversityofSingapore,Singapore
2
VanderbiltUniversity,USA
cjmbisg@gmail.com
1
Zinc Induce RPA And ssDNA Complex Into a Stiff And Stable
Structure That Cannot Form In Its Absence
The replication protein A (RPA) is a eukaryotic ssDNA binding
protein that has essential biological functions in cellular
metabolism such as DNA replication and DNA damage repair.
RPAconsists of threesubunits:RPA70, RPA32 and RPA14, and
each of them is made up of several subdomains. Previous
biochemicalstudiessuggestedthatthesequentialengagementof
RPAwithssDNAinvolvessequentialengagementofsubdomains,
which often yield several binding mode. We use magnetic
tweezers to study the dynamic binding activity of RPA to single
ssDNA. It is found that RPA‟s initial engagement with ssDNA
marked by a sudden increase of ssDNA extension before steady
state,whichprovidemore detailedinformationabouttherealtime
interaction between RPA and long ssDNA. In addition, RPA
contains a zinc-binding motif in its biggest subunit RPA70C. But
theroleofzinc-binding motif in RPA‟s sequential binding to ssDNA
hasnotbeenexaminedbefore.Usingmechanicalmanipulationof
ssDNA,wefoundthatzincdrivetheformationofasuperstiffand
stable RPA-ssDNA complex that cannot form in its absence.
Besides,thestiff RPA-ssDNAcomplex result from zinccan resist
digestion by Dnase to an extentmuch higher than that formed in
zinc free condition. In this sense, a physiological significance of
zinc on RPA‟s function is highlighted.
POSTER: BC-04
Juan Cheng*, Sarangapani Sreelatha, Ruizheng Hou, Artem
Efremov, Ruchuan Liu, Johan R. C. van der Maarel, and
Zhisong Wang
NationalUniversityofSingapore,Singapore
phychj@nus.edu.sg
Bipedal Nanowalker by Pure Physical Mechanisms
Artificial nanowalkers are inspired by biomolecular counterparts
from living cells, but remain far from comparable to the latter in
design principles. The walkers reported to date mostly rely on
chemical mechanisms to gain a direction; they all produce
chemical wastes. Here we report a light-powered DNA bipedal
walker based on a design principle derived from cellular walkers.
Thewalkerhastwoidenticalfeetandthetrackhasequalbinding
sites; yet the walker gains a direction by pure physical
mechanisms that autonomously amplify an intrasite asymmetry
intoaratcheteffect.Thenanowalkerisfreeofanychemicalwaste.
It hasadistinctthermodynamicfeaturethatitpossessesthesame
equilibrium before and after operation, but generates a truly
nonequilibrium distribution during operation. The demonstrated
design principle exploits mechanical effects and is adaptable for
useinothernanomachines.
POSTER: BC-05
6) Reimann, P. Brownian Motors: Noisy Transport Far from
Equilibrium.Phys.Rep.2002,361,57–265.
Juan Cheng*, Sarangapani Sreelatha, Long-Ying Loh,
Ruizheng Hou, Zhisong Wang
NationalUniversityofSingapore,Singapore
phychj@nus.edu.sg
7)Howard,J.Protein PowerStrokes.Curr.Biol.2006,16,R517–
R519.
Autonomous Artificial Nanomotor Integrating Ratchet and
Power Stroke for Efficient Utilization of Single Fuel Molecules
Nanoscalemotorshavethepotentialtoutilizeorconvertenergyby
extremeefficiency,whichhasimplicationsfornanotechnologyand
energytechnology.Aviableroutetowardsefficientnanomotorsis
to integrate ratchet-like and power stroke-like effects for
complementary production of a motor‟s directional output. We
demonstrate an autonomous nanowalker that couples the two
effectstoits fuel consumptioncycle in astep,controlledmanner,
thereby effectively channels the chemical energy of a single fuel
molecule into productive directional motion before its decay into
random heat. Were either effect impaired, more fuels must be
consumed per productive output. Implementing both ratchet and
power stroke mechanically, this rationally designed system
provides clues on how purely mechanical effects enable efficient
chemicalenergyutilizationatthesingle-moleculelevel.
POSTER: BC-06
Meihan Liu* 1, Ruizheng Hou 1, Juan Cheng 1, Long Ying Loh 1,
Sarangapani Sreelatha 1, Ju Nie Tey 2, Jun Wei 2, Zhisong
Wang 1
1
NationalUniversityofSingapore,Singapore
2
SingaporeInstituteofManufacturingTechnology,Singapore
liumhan@gmail.com
Autonomous Synergic Control of Nanomotors
Artificial nanomotors are inspired by biomolecular counterparts
fromlivingcells.Thesebiomotorsworkinginaliquidenvironment
withlargethermalfluctuations,theyconsumechemicalenergyand
convert it into directional motion or mechanical work. Bipedal
biomotors, such as Myosin V 1and Kinesin-1 2, can achieve
60%~70% efficiency(references), which is more than twice as
efficientasman-madegasolineengines3.
Theeffectivecontroloverthebiomotorsisthekeytoachievehigh
efficiency. Biological nanomotors often combine a ratchet-like
passivecontrol4-10withapower-stroke-likeactivecontrol5,7-9,1113tocomplementarilysuppressnonproductivechannel(futilestep)
and counter-productive channel (backward step) . This synergic
active-plus-passive control is critical to efficient utilization of
energy.14 It remains a challenge to integrate the two differing
types of control in rationally designed nanomotor systems.
Recently a light-powered track-walking DNA nanomotor was
developed from a bioinspired design principle9 that has the
potentialtointegratebothcontrols.15
However, it is difficult to separate experimental signals for either
controlduetoatightcouplingofbothcontrols.Herewepresenta
systematic study of the motor and its derivatives using light
operations.Theexperimentaldatasuggestthatthemotorachieves
the two controls autonomously through a mechanics-mediated
symmetrybreaking,inawaysimilartobiologicalnanomotors.This
study presents an experimental validation for the bioinspired
design principle of mechanical breaking of symmetry for synergic
ratchet-plus-powerstrokecontrol.
8)Wang,Z.S.;Feng,M.;Zheng,W.W.;Fan,D.G.KinesinIsan
Evolutionarily Fine-Tuned Molecular Ratchet-and-Pawl Device of
DecisivelyLockedDirectionality.Biophys.J.2007,93,3363–3372.
9) Wang, Z. S. Synergic Mechanism and Fabrication Target for
Bipedal Nanomotors. Proc. Natl. Acad. Sci. U.S.A. 2007, 104,
17921–17926.
10)Gennerich,A.;Vale,R.D.WalkingtheWalk:HowKinesinand
Dynein Coordinate Their Steps. Curr. Opin. Cell Biol. 2009, 21,
59–67.
11)Fox,R.F.RectifiedBrownianMovementinMolecularandCell
Biology.Phys.Rev.1998,E57,2177–2203.
12) Vale, R. D.; Milligan, R. A. The Way Things Move: Looking
under the Hood of Molecular Motor Proteins. Science 2000, 288,
88–95.
13) Mather, W. H.; Fox, R. F. Kinesin's Biased Stepping
Mechanism: Amplification of Neck Linker Zippering. Biophys. J.
2006,91,2416–2426.
14) Efremov, A.; Wang, Z. S. Maximum Directionality and
SystematicClassificationofMolecularMotors.Phys.Chem.Chem.
Phys.2011,13,5159–5170.
15) Cheng, J.; Sreelatha, S.; Hou, R. Z.; Efremov, A.; Liu, R. C.;
van der Maarel, J. R.; Wang, Z. S. Bipedal Nanowalker by Pure
PhysicalMechanisms.Phys.Rev.Lett.2012,109,238104.
POSTER: BC-07
Long-Ying Loh*, Juan Cheng, Artem Efremov, Zhisong Wang
NationalUniversityofSingapore,Singapore
iyloh@nus.edu.sg
A Modular Track-Walking Nanomotor
Motor proteins like kinesins, dyneins, and myosins, drive many
biological processes such as intracellular organelle transport, cell
division, and muscle contraction. This class of molecular motors
are nanomotors that bind to and walk along specific tracks,
converting chemical energy to perform mechanical work. Artificial
nanomotors are largely inspired by these biological counterparts
and are among the most sophisticated man-made nanomachines.
However, all track-walking nanomotors reported to date tend to
havemovementdrivenbyasinglemolecularpart,performingboth
engine-like energy-consuming switching and wheel-like binding.
This contrastswithmacroscopicmotorssuchasmoderncars,with
separated engine and wheels. Modular design concept used in
macroscopicmotorscouldintegrateexistingsimplernano-devices
with either „engine‟ or „wheels‟ function into a self-directed
nanomotor.Hereweproposeageneraldesignprincipleofmodular
nanomotors and present an experimental proof of concept by
implementing a light-responsivebipedalDNAnanomotor.
References:
1) Cappello G, et al., “ Myosin V stepping mechanism”. Proc Natl
AcadSciUSA,104(39):15328–15333,(2007).
2) Carter, N.J. and R.A. Cross, “ Mechanics of the kinesin step”.
Nature,435(7040):p.308-312,(2005).
3)http://en.wikipedia.org/wiki/Thermal_efficiency
4) Astumian, R. D. Thermodynamics and Kinetics of a Brownian
Motor.Science1997,276,917–922.
5) Oster, G.; Wang, H. Reverse Engineering a Protein: The
MechanochemistryofATPSynthase.Biochim.Biophys.Acta2000,
1458,482–510.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 79
POSTER: BC-08
James A. K. Tan
NgeeAnnPolytechnic,Singapore
tak@np.edu.sg
The Geno-Pheno Duality of Biophysics and Beyond
In the context of physics in general and cosmology in particular,
the author has proposed and discussed, in [1], the concept of
MESTIFandtheintegrativeandmutual-influencecharacteristicof
Mass-Energy(ME),Space-Time(ST)andInformationField(IF).In
thatpaper,IFhasbeendefinedasthesystemoftheorganization
and process of potential events. In the physical perspective, IF
defineshowMESTisorwillbeorganizedandexpressed.Physical
laws which are often represented with equations such as E=mc2
and F=mdv/dt+vdm/dt are representations of IF. That is, IF
providesthebasisofhowMESTisorganisedanddevelopedinan
integrativeconstrual.
In this paper, MESTIF is discussed from the perspective of
genetics, in which the DNA sequence (the genotype) is the
blueprint that controls the gene expression (the phenotype). The
objectives of this paper are to understand the integrative and
mutual-influence (here, the term duality is used to represent this
relation)ofgenotypeandphenotype(theGeno-PhenoDuality),the
constant changes and interchanges that are inherent in GenoPheno Duality, and to study the extension of the Geno-Pheno
Dualityintothenon-organicpartsofthemultiverse.
Thestudyoftheinterlink andmutual-influencebehaviourbetween
genotype and phenotype has been carried out for some time.
Ridley [2] uses the term “nature via nurture” as the title of his book
to imply that “genotype tells phenotype how to form, and
phenotype tells genotype how to reform”. Clearly, genotype is a
kind of IF and phenotype is category of MEST. Variation in
genotype is a natural process in evolution, in Darwin‟s natural
selectiontenet.Afishproducesthousandsofeggsthatmanyturn
into offspring, i.e. small fish, with slight variation between all of
them,andsomefinallysurviveandcontinuethegenerationalcycle
by producing their own offspring, and so on. The environment
affectsthesurvivalofthephenotype.Thoseoffspringthatsurvive
certainly provide “feedback”, in probabilistic and experimental
manner, to the genotype for continual changes to face the
subsequent round of uncertain challenges in the future
environment. It is experimental and trial-and-errorprocess,butthe
Geno-Phenointer-influenceisintimateandcloselyknit.
TheGeno-PhenoDualityimpliesthatwhenwestudyphenotype(a
kind of MEST), we need to concurrently analyse the genotype (a
typeofIF),andvice-versa.GenotypeasIFcontainstheplanand
intent,andphenotypeasMESTrepresentstheeventandoutcome.
The paper will also discuss the implication of the Geno-Pheno
Duality vis-à-vis MESTIF from the viewpoint of on non-organic
systems,withparticularemphasisondeterminism-uncertaintythat
isobservableinmanyeventsinthemultiverse.
1) Tan, James A.K. (2013), MESTIF – A Study Of The
Characteristics of Matter-Energy, Space-Time and InformationField, Conference in Honour of the 90th Birthday of Freeman
Dyson,NTU,Singapore,26-29August2013.
2) Ridley, Matt (2004), Nature Via Nurture – Genes, Experience
andWhatMakesUsHuman,HarperPerennial,London.
POSTER: BC-09
Jian-Qiang Zhong 1*, Xinming Qin 2, Jia-Lin Zhang 1, Satoshi
Kera 3, Nobuo Ueno 3, Andrew Thye Shen Wee 1, Jinlong Yang 2,
and Wei Chen 1
1
NationalUniversityofSingapore,Singapore
2
UniversityofScience&TechnologyofChina,China
3
ChibaUniversity,Japan
zjq@nus.edu.sg
Energy Level Realignment in Weakly Interacting DonorAcceptor Binary Molecular Networks
Understandingtheeffectofintermolecularandmolecule-substrate
interactions on molecular electronic states is key to revealing the
energy level alignment mechanism at organic-organic
80 | The 8th OCPA International Conference on Physics Education and Frontier Physics
heterojunctions or organic-inorganic interfaces. In this paper, we
investigate the energy level alignment mechanism in weakly
interacting donor-acceptor binary molecular superstructures,
comprising copper hexadecafluorophthalocyanine (F16CuPc) and
copper phthalocyanine (CuPc), or manganese phthalocynine
(MnPc)ongraphite.Themolecularelectronicstructureshavebeen
systematically studied by in-situ ultraviolet photoelectron
spectroscopy (UPS), low-temperature scanning tunneling
microscopy/spectroscopy (LT-STM/STS) experiments and
corroborated by density functional theory (DFT) calculations. As
demonstrated in the UPS and LT-STM/STS measurements, the
observedunusualenergylevelrealignment(i.e.,alargedownward
shiftinthedonorHOMOlevelandacorrespondingsmallupward
in the acceptor HOMO level) in the CuPc-F16CuPc binary
superstructures originate from the balance in intermolecular and
molecule-substrate interactions. The enhanced intermolecular
interactions through the hydrogen bonding between neighboring
CuPc and F16CuPc can stabilize the binary superstructures and
modify the local molecular electronic states. The obvious
molecularenergylevelshiftwasexplainedbygapstatesmediated
ininterfacialchargetransfer.
Reference:
J.Q.Zhong,X.M.Qin,J.L.Zhang,S.Kera,N.Ueno,A.T.S.Wee,
J.L.Yang,W.Chen,ACSNano,8,5941-5951(2014)
POSTER: BC-10
Computational and Mathematical Physics
POSTER: CP-01
*Li Chen, Z. F. Wang, and Feng Liu
LinyiUniversity,China
lchen.lyu@gmail.com
Robustness of two-dimensional topological insulator states in
bilayer bismuth against strain and electrical field
Using first-principles and Wannier function methods, we
systematically calculate the electronic band structure and
topologicaledgestatesofsinglebilayerBi(111)film(BL-Bi)asa
functionofstrainandperpendicularelectricfieldtoinvestigatethe
effectsinducedbylatticemismatchandinterfacialchargetransfer
whenBL-Biisepitaxiallygrownonasubstrate.Wefound that the
BL-Biremainswithafinitebandgapandanontrivialbandtopology
for strains up to ±6% and electric fields up to 0.8 eV/A°. This
indicates that the BL-Bi is a robust two-dimensional topological
insulatoragainststrainandelectricalfieldon asubstrate.
POSTER: CP-02
Zhensheng Zhong*, Lai Huat Soh, and Gang Chen
NanyangTechnologicalUniversity,Singapore
Zzhong3@e.ntu.edu.sg
Farica E. Yosafat*, Ivonne M. Radjawane, Totok Suprijo
1)ParahyanganCatholicUniversity,Indonesia
2)InstitutTeknologiBandung,Indonesia
farica86@gmail.com
Unravelling the Stabilizing Effect of a U∙U pair in an RNA by
Mechanical Force
Simulation of Marine Debris Drift on Bali Strait Using Particle
Trajectory Model
Watson-Crick base pairs are the major component of double
helical structures in RNA; their structures and stabilities are well
understood. Non-Watson-Crick base pairs are less well
characterized, despite the fact that they are critical in
(de)stabilizing RNA secondary structures, shaping RNA into
complex tertiarystructures, and providing unique local and global
structures for ligand binding. Here, we used opticaltweezers and
to study the contribution of U∙U and U∙C pairs in an internal loop to
the mechanical folding energy landscape of a hairpin in human
telomerase RNA. Our single-molecule mechanical unfolding
studies show that a U∙U mismatch is more stable than a U∙C
mismatch, consistent with our ensemble thermal melting studies.
The U∙U to U∙C mutation, which disrupts one hydrogenbondand
is located 6 Watson-Crick base pairs away from theterminal end
of the hairpin, lowers the mechanical unfolding energy barrier
allosterically (by lowering the unfolding force by ~1 picoNewton
(pN) per mutation) without affecting the unfolding transition state
position. Themechanical folding transitionstate position fromthe
moves towards the fully folded hairpin structure upon U∙U to U∙C
mutation, suggests a 13-nucleotide misfolded state exists for the
mechanical folding of the hairpins. Thus, a conservative single
mutation within a non-Watson-Crick region may affect RNA
stabilityandbiologicalfunctionsinvolvingRNA(un)folding.
Particletrajectorymodelwasutilizedtosimulateseasonalmarine
debrisdriftonBaliStraitandtopredictsource(s)ofthedebristhat
stranded on Kuta Beach Bali. Simulations were conducted along
northwest monsoon season from 1 December 2011 to 31 March
2012.
POSTER: BC-11
Zicong Zhou
TamkangUniversity,Taiwan
zzhou@mail.tku.edu.tw
Multiple-step discontinuous transitions in extension for an
intrinsically curved semiflexible biopolymer
We study the effect of an intrinsic curvature on the mechanical
property of two-dimensional semiflexible biopolymers. We show
exactly that in the ground state the extension of an intrinsically
curved semiflexible biopolymer of finite length can undergo a
multiple-stepdiscontinuoustransitionregardlessofbendingrigidity.
Thetransitionisaccompaniedbyunwindingloops,andthecritical
force reaches a limit quickly with decreasing number of loops so
that, in the experiment, it is possible to observe the almost
simultaneousopeningofseveralloops.
3)KersonHuang,ChiXiong,XiaofeiZhao,Scalar-FieldTheoryof
Dark Matter, International Journal of Modern Physics A, Vol. 29
(2014)
Two scenarios have been simulated based on Euler-Lagrangian
equation. Twelve particles were released continuously from the
sources, which were assumed as rivers/waterways facing Bali
Strait.Inthesecondscenario,adispersiontermwasintroducedto
the equation to allow particles to drift with higher degree of
freedom.
Analysisofmodeloutputsuggestedthatmarinedebrisstrandedat
Kuta Beach Bali are more likely from Bali Island itself, especially
fromBadungandTabananareas.
POSTER: CP-03
Yulong Guo
SouthChinaUniversityofTechnology,China
1289154894@qq.com
Lattice Boltzmann Method Applied in Superfluid Universe
Simulation
The Lattice Boltzmann method is an emerging computational
approach to solving many PDE systems, such as the NavierStokes equation for fluid dynamics, the wave equation for wave
propagation,andtheNonlinearSchrodingerequationforquantum
mechanics. A theory for superfluid universe has been formulated
under a nonlinearKlein-Gordon equation that is verysuited to be
solved by the Lattice Boltzmann method. In this work, the
simulationiscarriedoutbyLatticeBoltzmannmethod,whichisat
the same time compared to finite difference solutions, showing
great consistency.
References:
1) Yan Guangwu, A Lattice Boltzmann Equation for Waves,
JournalofComputationalPhysics161,61-69(2000)
2)JianyingZhang,GuangwuYan,LatticeBoltzmannModelforthe
Complex Ginzburg-Landau Equation, Physical Review E 81,
066705(2010)
POSTER: CP-04
Syailendra Harahap
SuryaUniversity,Indonesia
syailendra.harahap@surya.ac.id
Outdoor Riffle Simulator for SS1 & SS2 Using Infrared LASER
Shootingisoneofthebasicskillinarmy.Theonlywaytomaintain
shootingskillandaccuracyisbyshootingtraining.Therearesome
problem in shooting training, such as safety and limitation of
ammunition.Tosolvethisproblem,Idevelopedshootingsimulator
using infrared LASER on a riffle (replica) for aiming and pulling
trigger training. The LASER used for replace ammunition. I use
micro controller for transmit the LASER with unique ID, so each
riffle will have different ID. On receiver I use micro controller,
infrared receiver and a modified android camera for receive
LASER coordinate and riffle's ID on the target. The ID and
coordinate will be processed in computer using software for
calculating ballistic and other calculations and the result will be
displayedoncomputer.Iusetheactualtargetforshootingtraining
and only add some marking points for calibration for modified
android camera. This simulator is designed for "SS1" and "SS2"
riffle for indoor and outdoor use with actual target distance for
shooting training.
POSTER: CP-05
Hui Jiang, Christian Kloc
NanyangTechnologicalUniversity,Singapore
Jianghui@ntu.edu.sg
Single-Crystal Growth of Organic Semicondutcors
Organic single crystals have been widely investigated in recent
years due to the wide spread expectation that the transport
properties measured on single crystals present the intrinsic
properties of organic semiconductors. The single-crystal growth
methods of organic semiconductors are discussed in our studies.
Organic small molecules, such as anthracene, tetracene,
pentacene, rubrene, perylene, fluorinated metal phthalocyanine,
etc.,areselectedforcrystalgrowth.Organicsingle crystals charge
transfer compounds with forms of one-dimensional micro/nanowires, two-dimensional platelets and three-dimensional
cubesarealsosynthesizedbybothsolutionmethodandphysical
vapor transport method. Field-effect transistors (FETs) based on
organic single crystals arefabricated and highmobility of upto 1
cm2V-1s-1 can be obtained. Some potential applications like
phototransistors and gassensordevices based on organicsingle
crystalFETsarealsointroduced.
POSTER: CP-06
Lilik Hasanah*, Yuyu Rahmat Tayubi, Endi Suhendi and Budi
Mulyanti
IndonesiaUniversityofEducation,Indonesia
lilikhasanah@upi.edu
Tunneling Current for Simple MOS Structure of n+ Poli
Si/SiO2/p-Si (100) as Anisotropic Material
Simulationoftunnelingcurrentinn+poliSi/SiO2/p-Si(100)simple
MOSstructurebytreatingSiasanisotropicmaterialisdoneinthis
research. The calculation is done by including the effect of
couplingofparallel-perpendicularkineticenergy.Theresultshows
thattunnelingcurrent-voltage(IV)characteristicsissensitivetothe
value of electron velocity. Tunneling current tends to decrease
when the thickness of SiO2 is increased. The result is then
compared with the calculation in which Si is treated as isotropic
material. Fitting with experimental data proves that the result of
calculationusinganisotropicmaterialassumptionissimilarwiththe
data in high oxide voltage. In contrary, in low oxide voltage, the
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 81
result of calculation using isotropic material assumption is similar
withthedata.
Condensed Matter and Materials Sciences
POSTER: CP-07
POSTER: CM-01
Linfeng Sun , Zexiang Shen
NanyangTechnologicalUniversity,Singapore
S110016@e.ntu.edu.sg
A. Purwanto*, A. Fajar, H. Mugirahardjo, J. W. Fergus, K.
Wang
1)SuryaCollegeofEducation,Indonesia
2)NationalNuclearEnergyAgency,Indonesia
3)AuburnUniversity,USA
agus.purwanto@stkipsurya.ac.id
Probing the Spin-orbit Splitting in Single Layer MoS2 by Triply
Resonant Raman Scattering
Thoughthegiantspin-orbitsplittingofsingle-layerMoS2hasbeen
proposed, such splitting has not been studied effectively in
experiments. This Letter reports the valence band spin-orbit
splitting in single-layerMoS2 firstly, probed by the triply resonant
Raman scattering process. We found that upon 325 nm laser
irradiation, the second order overtone and combination Raman
modes of single-layer MoS2 are dramatically enhanced. Such
resonant Raman enhancement arises from the electron-twophonontripleresonanceviathedeformationpotentialandFrohlich
interaction. As a sensitive and precise probe for the spin-orbit
splitting, the triply resonant Raman scattering will provide a new
andindependentroutetostudythespincharacteristicsofMoS2.
POSTER: CP-08
Jiaxu Yan*, Lei Liu, Jer-Lai Kuo, Zexiang Shen
NanyangTechnologicalUniversity,Singapore
S090062@ntu.edu.sg
Huge Excitonic Effects in a-MoO3: From Bulk to Monolayer
Although a-MoO3 has been found widespread use in solid state
microbatteries and heterogeneous catalysis, its electronic and
particularly optical properties still have not been well established.
The resulting computed in-plane polarized optical spectrum,
obtained by solving the Bethe-Salpeter equation for many-body
Greenfunction,isinexcellentagreementwithexperimentandhas
astronganisotropy.Adetailedanalysisoftheexcitonicstructures
within the band gap shows strong excitonic effects with a
significantly large binding energyassignedtothe bound excitons.
This provides an explanation for the observed „‟optical gap‟‟
contradictionsbetweenexperimentsandtheories.
Possible Magnetic Structures on Mn0.76 Co0.58 Cr1.66 O4
Westudythemagneticstructureof Mn0.76 Co0.58 Cr1.66 O4 at
26K.Theroomtemperatureand26Kmagneticneutrondiffraction
was conducted at the Neutron Scattering Laboratory, Indonesia.
The crystallographic structure is based on the room temperature
data which was published elsewhere. It crystallizes in the cubic
spinel F d -3 m space group. At 26K, the magnetic contributions
canbeindexedas(111),(220),(331)and(422)inthecubiccrystal
system belonging to the parent phase. The last three reflections
are pure magnetic contributions. We used the representation
theorytodeducepossiblemagneticstructureswithzeromagnetic
propagationvector.Aquickinspectionbasedonthemodelandthe
magnetic structure factor to exclude some configurations is
discussed.
POSTER: CM-02
Wei-Cheng Wang 1,2, Peranders Glans 2, Jinghua Guo 2 ShihYun Chen 3, Ren-Jie Chen 3,4, Kang-Wei Fong 3 ,Chi-Liang
Chen 5, Ting-Shan Chan 4 ,Ching-Lin Chang*1,Chung-Li Dong 4,
Alexandre Gloter 6 , Jin-Ming Chen 4 , Jhy-Fu Lee 4
1
TamkangUniversity,Taiwan
2
LawrenceBerkeleyNationalLaboratory,USA
3
NationalTaiwanUniversityofScienceandTechnology,Taiwan
4
NationalSynchrotronRadiationResearchCenter,Taiwan
5
AcademiaSinica,Taiwan
6
UniversityofParisSud,France
clcahang@mail.tku.edu.tw
Effect of Fe Doping on Electronic and Magnetic Properties of
Room Temperature Ferromagnetic CeO2 Nanocrystals
This study reports the electronic structure of Fe doped CeO2
nanoparties (NPs) determined by coupled X-ray absorption
spectroscopy (XAS)andX-rayemissionspectroscopy(XES).The
oxygen K-edge shows the feature-rich spectra due to the
hybridization of cerium 4f5d-oxygen 2p states and these fine
structuresareverysensitivetotheoxidationstateandarestrongly
dependent on the concentration of Fe doping. The change of
charge state upon doping observed from O K-edge is consistent
with that observed from the Ce M4, 5-edges. Moreover, the
concentrationoftheCe3+/Ce4+canbeestimatedfromtheCeM4,
5-edges. The oxygen vacancies canbeinducedbytheFedoping.
BycomparethelocalelectronicstructurearoundCesiteandthat
aroundFesite,thechargetransferbetweenFeandCeisrevealed.
Thebandgapisdeterminedbythecombinedabsorption-emission
spectrum. Furthermore, the defect structure is crucial in the
occurrenceofthemagnetismintheseNPs.
POSTER: CM-03
Po-Tuan Chen*, Chia-Liang Sun, and Michitoshi Hayashi
NationalTaiwanUniversity,Taiwan
r92222019@ntu.edu.tw
Theoretical Calculations of Edge Effects for O2 Adsorption
and Dissociation on N-Doped Graphene Ribbons
We have performed the calculations of O2 and dissociated O2
adsorbing on N-doped graphene nanoribbon (NGNRs) models
using density functional theory to elucidatethe origin of oxidation
reduction reactions of NGNRs. Our experimental X-ray
photoelectron spectroscopy analysis suggests that the pyridinictype N dopants play the major function of ORR in NGNR
82 | The 8th OCPA International Conference on Physics Education and Frontier Physics
electrodes. In addition, the pyridinic-type N dopants can be
containedinpyridine,pyridinium,orN inthegraphenesheetwitha
nearbyvacancy(NV)models.Thus,thesignificantN-dopedribbon
models were constructed within 1D periodic boundary condition,
andwecouldtheoreticallyexaminetheORRpropertiesnaivelyat
zigzagedge(Z)orarmchairedge(A).Z-pyridineisexothermalfor
dissociated O2 adsorbing, while Z-pyridinium is endothermal for
dissociated O2 adsorbing. A-pyridine is poor for dissociated O2
adsorbing, and dissociated O2 can be thermally preferable
adsorbing on A-pyridinium. Interestingly, both of Z-NV and A-NV
display the strongest adsorption abilities. The NV models can be
themostpotentialcandidateforORRapplication.
POSTER: CM-04
Chunxiao CONG*, Ting YU
NanyangTechnologicalUniversity,Singapore
cxcong@ntu.edu.sg
Resonant Low Frequency Interlayer Shear Modes in Folded
Graphene Layers
Few-layer graphene (FLG) has attracted tremendous attention
owingtoitsexceptionalelectronicpropertiesinheritedfromsingle
layer graphene (SLG) and new features led by introducing extra
freedoms like interlayer stacking sequences or rotations.
Effectively probing interlayer shear modes are critical for
thoroughlyunravellingmechanicalandelectricalpropertiesofFLG
and further develop its practical potential. Unfortunately, shear
modes areextremelyweakandalmostfullyblockedbyaRayleigh
rejecter in Raman measurements. This greatly hinders
investigations of shear modes in FLG. Here, we demonstrate
dramatically enhancing of shear modes by properly folding FLG.
Asadirectbenefitof thestrongsignal,enhancementmechanism,
vibrationalsymmetry,anharmonicityandelectron-phononcoupling
of the shear modes are uncovered through studies of Raman
mapping, polarization- and temperature-dependent Raman
spectroscopy.Thisworkcomplements Ramanstudiesofgraphene
layers, and paves an efficient way to exploit low frequency shear
modesofFLGandothertwo-dimensional layered materials.
POSTER: CM-05
W. L. Gan*, I. S. Kerk, D. W. Wong, W. S. Lew
Nanyang Technological University
wgan1@e.ntu.edu.sg
2D Transport of Superparamagnetic Microbeads on a
Ferromagnetic Hexagonal Nanolattice
Surface-functionalized superparamagnetic (SPM) beads have
beenwidelyusedtodetectandmanipulatechemicalandbiological
agentsinlab-on-a-chip systems. Recently,ithasbeenshownthat
byexploitingthestrayfieldgeneratedbydomainwallsinmagnetic
nanostructures,itispossibletocaptureandcoupleaSPMbeadto
adomainwall.Tostorethecapturedbead,thedomainwallscan
be pinned by fabricating geometrical defects on the nanotracks.
Furthermore, the position of the coupled SPM bead can be
pinpointedbymeasuringthemagnetoresistanceacrossnanotrack
sections. However, studies on such systems have so far been
limitedto1Dtransport.
In this work, we develop a novel structure to manipulate SPM
beads across a substrate surface. While domain wall trajectory
under a constant field has been well studied, we found that by
applying a biasfield in the direction of a branch,the domain wall
canbeforcedtopropagateinthedirectionoftheselectedbranch.
Replicatingthestructureintoalatticeof120°Y-branchessimilarto
ahoneycombpattern,wecanfinallyshuttletheSPMbeadsacross
a 2D surface. To verify the simulation results, the lattice was
fabricated using a combination of electron beam lithography and
magnetronsputtering.Toincreasethepinningforceexertedbythe
domain wall on the SPM bead, we also studied the effects of
applyingamagneticfieldperpendiculartothelatticeplane.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 83
POSTER: CM-06
POSTER: CM-09
Jian-Feng Ge*, Zhi-Long Liu, Canhua Liu, Chun-Lei Gao, Dong
Qian, Qi-Kun Xue, Ying Liu, Jin-Feng Jia
1)ShanghaiJiaoTongUniversity,China
2)TsinghuaUniversity,China
3)PennsylvaniaStateUniversity,USA
Gejianfeng305@163.com
Lunhui Hu*, Yi Zhou, Fuchun Zhang
ZhejiangUniversity,China
hu.lunhui.zju@gmail.com
Superconductivity in Single-Layer Films of FeSe on SrTiO3
with a Transition Temperature above 100K
We report in situ 4-point probe (4PP) measurements of singlelayerfilmsofFeSegrownonconductingNb-dopedSrTiO3(001)by
molecular beam epitaxy (MBE) that were found recently to show
interface enhanced superconductivity marked by a large
superconducting energy gap indicating a superconducting
transition temperature (Tc) higher than that of bulk FeSe or any
Fe-based superconductors. Using the 4PP technique we
demonstrated the occurrence of superconductivity in the singlelayerFeSeatatemperatureashighas109K.
POSTER: CM-07
Huang Han 1*, Wan Wen1 , Li Hui 2, Wong Swee Liang 3, Gao
Yongli 1, Andrew Thye Shen Wee 3
1
TheCentralSouthUniversity,China
2
ChineseAcademyofSciences,China
3
NationalUniversityofSingapore,Singapore
physhh@csu.edu.cn
Incorporating isolated molybdenum (Mo) atoms into Bilayer
Epitaxial Graphene on 4H-SiC(0001)
The atomic structures and electronic properties of isolated Mo
atoms in bilayer epitaxial graphene (BLEG) on 4H-SiC(0001) are
investigated by low temperature scanning tunneling microscopy
(LT-STM). LT-STM results reveal that isolated Mo dopants prefer
to substitute C atoms at α-sites,andpreferentiallylocatebetween
thegraphenebilayers.First-principlescalculationsconfirmthatthe
embedding of single Mo dopants within BLEG is energetically
favorable as compared to monolayer graphene. The calculated
bandstructures show that Mo-doped BLEG is n-doped, and each
Mo atom introduces a local magnetic moment of 1.81 μB. Our
findings demonstrate a simple and stable method to incorporate
singletransitionmetaldopantsintothegraphenelatticetotuneits
electronic and magnetic properties for possible use in graphene
spin devices.
Numerical Study of Majorana Zero Mode
We show that a thin film with spin-orbit coupling can be in a
quantum topologically ordered state, supporting exotic Majorana
zeromode.ThekeytoMajoranazeromodeisthecoexistenceof
spin-orbit
coupling
with
proximity-induced
s-wave
superconductivity. We consider the Hamiltonian under sphere
symmetry,andcalculatetheeigenvalues,wavefunctionsforzero
mode,andthelocaldensityofstates.Then,wearguethatwemay
findMajoranazeromodeinsuchmodeanddiscussthefinite-size
effect.
POSTER: CM-10
Che-Wei Huang*; Tien-Tien Yeh, Hsuan-Yin Chen, Y.F. Chiang,
J.C.A. Huang, Chih-Wei Luo, Chao-Kuei Lee
1)NationalSunYat-senUniversity,Taiwan
2)NationalChiaoTungUniversity,Taiwan
3)NationalChengKungUniversity,Taiwan
chester3151@gmail.com
Ultrafast Dynamics Investigation of MBE Growth Bi2Se3 Films
Using Femtosecond Pump-Probe Measurement
Inthiswork,ultrafastdynamicsofMBEgrowthtopologicalinsulator
Bi2Se3 films were investigated using femtosecond pump probe
measurement.Roleofbulk state(BS)andsurfacestate(SS)were
observed clearly and discussed. Compared to relaxation time of
around 1.7ps with 800nm probe beam, longer relaxation time
ranging from 2ps to 4ps with increasing pump power is
investigatedwith12.29umMIRprobebeam. Inter-valley scattering
ofexcitedcarrierwhichisfrombulkstateonlyisobservedforMIR
probebeam.
POSTER: CM-11
Jeil Jung1*, Ashley DaSilva2, Allan H. MacDonald2, Shaffique
Adam1
1
NationalUniversityofSingapore,Singapore
2
TheUniversityofAustinatTexas,USA
jeil.jung@gmail.com
POSTER: CM-08
Origin of Band Gaps in Graphene on Hexagonal Boron Nitride
Xu He
InstituteofMaterialResearchandEngineering,Singapore
hexu1995@gmail.com
Band gaps have recently been observed in graphene on
hexagonal boron nitride. Existing models for the interaction
between graphene and boron nitride substrate are unable to
account for this insulating phase. Motivated by very recent
experimental data observing bond distortion of graphene on a
boron nitride substrate, we present a new mechanism for which
band gaps can be induced due to strains in graphene on
hexagonal boron nitride. Using an electronic structure model
applied for distorted lattices obtained from Born-von Karman
elasticity theory we show that sizeable band gaps in the order of
tensofmeVcanopeninthelimitoflongmoireperiods.
Thin Broadband Terahertz Metamaterial Absorber
A broadband terahertz (THz) metamaterial absorber (MA) with
polarization-independence in x, y directions is modeled and
investigated using CST Studio Suite. Its three-layer-structure
designiscomposedofanickelgroundplane,apatternofsquare
nickelpillar,andanN-typedopedsiliconspacerlayerinbetween.
The dielectric constant ε of the spacerlayeriscalculatedfromthe
transmittance in the frequency range of 1.5-7 THz of the N-type
doped silicon sample, measured with a Time-Domain-Sampling
spectroscopy system. By optimizing the parameters of the
broadband MA through simulation, asuper broadband absorption
bandwidth covering over 5 THz frequency range with absorbance
over 60% is obtained. The bandwidth of the THz MA is much
broaderthanthatofthosepublisheduptodate.Thetotalthickness
of the absorber is less than 14 μm. The super broadbandMAcan
be realized by using typical patterning and fabricating techniques
includingmetaldeposition,sputteringdeposition,photolithography,
electrolysis and ion milling.
84 | The 8th OCPA International Conference on Physics Education and Frontier Physics
POSTER: CM-12
Ke WU, Guanggeng YAO, Wentao XU, Ziyu LUO, Wei CHEN,
Andrew WEE, Xue-Sen WANG
NationalUniversityofSingapore,Singapore
phywuke@nus.edu.sg
Hydrogenation on Bi(111) Thin Films
First-principles calculations predict 2D topological insulators such
asBiH withextraordinarilylargebulkgaps(ZhigangSong,etal.).
SoBiHthinfilmcanbetakenasagoodcandidatetoachieve2D
TI.
Basedonthis,wecarriedouthydrogenationon10bilayerBi(111)
prepared on Si 7×7 in UHV STM system. Hydrogenation induces
bucklingwithslightchangeofthelatticeofBi(111).Thebuckling,
whose height differenceis at therange of ~0.3 nm, influencethe
electronic structure of Bi(111). dI/dV spectrum experiments
revealed that the lower regions of the buckling morphology show
largerDOSatabout40meVwhilethehigherregionsbearlarger
DOSatabout-40meV.
POSTER: CM-13
Keola Wierschem*, Pinaki Sengupta
NanyangTechnologicalUniversity,Singapore
keola@ntu.edu.sg
Quenching the Haldane Gap in Spin-1 Heisenberg
Antiferromagnets
We consider a quasi-one-dimensional system of spin-1
Heisenberg antiferromagnetic chains in 2D and 3D hypercubic
latticeswithinterchaincouplingJanduniaxialsingle-ion anisotropy
D. Using large scale numerical simulations, we map out the J--D
phase diagram and investigate the low lying excitations of the
Haldane phase in the weak coupling limit (small J). Through
calculation of the newly proposed strange correlator, we provide
direct evidence that the Haldane phase remains a non-trivial
symmetryprotectedtopologicalstateforsmallbutfiniteinterchain
coupling.
POSTER: CM-14
Bo-Tsang Chen, Wei-Chen Tien, Wun-Long Yen, Yi-Jen Chiu,
Ann-Kuo Chu, Chao-Kuei Lee*
NationalSunYat-SenUniversity,Taiwan
omnivictor219@gmail.com
High Optical Quality Tantalum Pentoxide Thin Film
Fabrication By Magnetron Sputter System
Using RF reactive magnetron sputtering, high optical quality
Ta2O5 thin film was grown and analyzed. The optimized surface
roughnessaslowas0.12nmwasobtainedasannealingwiththree
hours attemperature of 650C. In addition, ultra-low crack density
indicatesthatthepropagationlossaslowas1dB/cmisexpectable.
Thisrevealsthepotentialforphotoniccircuit.
be induced and tuned by breaking the inversion symmetry of the
two layers. Indeed, the interlayer asymmetry, which doesn‟t exist in
monolayer graphene, between the on-site energies in two layers
canleadtoasignificantmodificationofthebandstructureBLG.In
this work, magnetopolariton in BLG is theoretically investigated
withtheconsiderationoftheinfluenceofasymmetrybetweenonsite energies in the two layers of BLG. The results show that an
ultrastronglight-mattercouplingregimecanbeachievedinahigh
fillingfactorandasymmetryhasastrongeffectonit.AlthoughBLG
in the low energy regime and semiconductor have a similar
quadraticdispersionofquasiparticles,aremarkablydifferentcavity
quantumelectrodynamics(QED)effectoccursinBLG.Inparticular,
a quantum phase transition, as predicted by the Dicke model,
occursinBLG in spite of theSchrodinger-like term p^2/2m in the
system Hamiltonian, while such quantum phase transition doesn‟t
exist in semiconductors. Most noticeably, the ultrastrong lightmatter coupling can be easily controlled by modulating the
asymmetry in BLG, which provides an excellent platform to
observeinterestingQEDeffectsandcanleadtotunablepolaritonbaseddevicesandcavity-controlled magneto-transportinBLG.
POSTER: CM-16
Junpeng Lu*, Chorng Haur Sow
NationalUniversityofSingapore,Singapore
phyljp@nus.edu.sg
Micro-Landscaping of Au Nanoparticles on Few-layer MoS2
Films
Surface modification/decoration of ultrathin MoS2 films with
chemical moieties is appealing since nanointerfacing can
functionalize MoS2 films with bonus potentials. In this work, we
developed a facile and effective method for micro-landscaping of
Aunanoparticlesonfew-layerMoS2films.Thisapproachemploys
a focused laser beam technique to pre-modify the MoS2 films to
achieveactivesurfacedomains.Thisisfollowedbysimplydipping
the modified films into AuCl3 solution for a few minutes and Au
nanoparticles are found to preferentially decorate onto the
modifiedregions.Asaresult,wecanselectivelyandlocallyanchor
Au nanoparticles onto designated regions on the MoS2 surface.
With a scanning laser beam, micropatterns with well-defined
structuresareconstructedbyself-assemblyofAunanoparticles.In
addition, varying the laser power, reaction time and MoS2
thickness can control the size and density of the particles. The
resulting hybrid materials are demonstrated as efficient Raman
active surfaces for the detection of aromatic molecules. High
sensitivity is exhibited by the as-fabricated Au nanoparticle-MoS2
hybridsurfaceenhancedRamansubstrates.
POSTER: CM-15
Liu Tao* and Qi Jie Wang
1)NOVITAS, NanyangTechnologicalUniversity,Singapore
2)CDPT,NanyangTechnologicalUniversity,Singapore
tliu1@e.ntu.edu.sg
Tunable ultrastrong light-matter coupling in bilayer grapheme
Light-mattercouplinginamicrocavityhasbeenafascinatingtopic
forfundamentalstudiesofcavityquantumelectrodynamics(QED).
For applications in quantum devices, enhancing and tuning the
coupling strength are crucial. In the ultrastrong light-matter
coupling regime, which can be achieved when the interaction
strength between an excitation and the cavity photon becomes
comparable to or larger than the corresponding electronic
transition frequency in a high finesse cavity, a dramatic
modificationtothepropertiesofquantumgroundstateisachieved.
This can lead to a very interesting non-adiabatic cavity QED
phenomena.
Graphene,a2Dhoneycombcrystalofcarbonatoms,hasdiverse
cavityQEDphenomenaforbothfundamentalandappliedstudies.
Moreover, recent hybrid graphene/metamaterial devices further
pavethewayforcavityQEDexperimentsingrapheneresonators.
In contrast to monolayer graphene with linear dispersion, bilayer
graphene(BLG),stackedintheBernalsequence(A-Bstacking),is
characterized by a massive Dirac spectrum with the quadratic
dispersioninthelowenergyregime.TheinversionsymmetricABstacked BLG is a zero-bandgap semiconductor with a parabolic
dispersioninthelowenergyregime,butanon-zerobandgapcan
POSTER: CM-17
Yao Lu* , Jie Liu , Xiongjun Liu and K.T. Law
TheHongKingUniversityofScienceandTechnology,HongKong
yluae@ust.hk
Realization of DIII Class Topological Superconductor by
Using Quantum Spin Hall Material and S-wave
Superconductor
In this work, we show that a quantum spin Hall insulator in
proximity to an s-wave superconductor can be tuned into
topological superconductors in different symmetry classes. For
example,intheabsenceofexternalmagneticfield,thesystemcan
be a DIII class topological superconductor which respects timereversal symmetry. In the presence of magnetic field, the system
can be in the BDI class which supports different numbers of
localized Majorana fermions where the number of Majorana
fermions depends on the strength of the applied magnetic field.
We point out that the different topological classes can be
distinguishedbytransportmeasurements.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 85
POSTER: CM-18
Ziyu Luo*, Guanggeng Yao, Wentao Xu, Feng Pan, Ke Wu,
Yuanping Feng, Xue-sen Wang
NationalUniversityofSingapore,Singapore
a0076584@nus.edu.sg
STS and DFT Investigations of Surface States in Sb and Bi
(111) films
Bulk Sb and Bi are both semimetals. Sb is regarded to be
topological nontrivial, while Bi is topological trivial because of the
difference in spin-orbit coupling. We aim to investigate the
difference between their surface states by scanning tunneling
microscopy/ spectroscopy (STM/STS) experiments and density
functionaltheory(DFT)calculations.Thequasiparticleinterference
(QPI)patternsonbothSbandBifilmsaredetectedbytheFouriertransform scanning tunneling spectroscopy (FT-STS). These QPI
patterns can also be simulated by the bandstructures from DFT
calculations. By comparing the quasiparticle interference (QPI)
patterns from FT-STS and DFT, we may obtain the spin textures
andpenetrationdepthinthesurfacestates.Moreover,itmayalso
helptotracktheevolutionofthesurfacestatesfromSbtoBi and
demonstratetheeffectofthespin-orbitcouplingonthesesurface
states.
POSTER: CM-19
Lu Lyu*, Lei Zhang, Dongmei Niu, Han Huang, Haipeng Xie,
Ningtong Cao, Yongli Gao
CentralSouthUniversity,China
lvlu114@csu.edu.cn
The Investation on Phase Transition of CuPc Grows on HOPG
Substrate
The evolutions of phase and corresponding electronic structures
asfunctions of the thickness of CuPc films on HOPG have been
investigated with ultraviolet photoemission spectroscopy(UPS) ,
XPS and AFM. At a deposition rate of 0.2 nm/min, the vaccumlevel(VL) of CuPc/HOPG gradually decreases and the HOMO of
CuPc in the low-binding energy region near the EF becomes
broader due to the appearance of a new component. (define PA
andPB!).ThePBpeakslightlyshiftstothe high-EBsideandthe
PA peak is observed no apparent shift. It is consistent with
previousresearch[1-3].TheresultsofXPSandAFMindicatesthat
phase transition takes please in thicker CuPc films. The KFM
shows the two phases have different surface potential (SP). Out
results shows that on HOPG the CuPc molecular orientation
changesfromflat-lying to tilted at very thin region.
POSTER: CM-20
Jian-Jian Miao*, Dong-Hui Xu and Yi Zhou
ZhejiangUniverisity,China
miaojianjian@zju.edu.cn
Schwinger-boson Mean Field Theory of the Quantum XXZ
Model with Dzyaloshinskii-Moriya Interactions
ThequantumXXZmodelwithDzyaloshinskii-Moriya interactions is
studied by Schwinger boson mean field theory. We find a state
withlowerenergythantheRVB state near the Ising limit.This state
is charactered by two order parameters. A phase diagram to
describe the crossover from Ising point to isotropic Heisenberg
pointistobeestablished.
POSTER: CM-21
Namphung Peimyoo1*, Jingzhi Shang1, Chunxiao Cong1,
Xiaonan Shen1, Xiangyang Wu1, Edwin K. L. Yeow1, Ting Yu 1,2
1
NanyangTechnologicalUniversity,Singapore
2
NationalUniversityofSingapore,Singapore
namphung1@e.ntu.edu.sg
86 | The 8th OCPA International Conference on Physics Education and Frontier Physics
Photoluminescence from Triangular Monolayer WS2
Synthesized via Chemical Vapor Deposition
Light emission of monolayer WS2 (1L-WS2) triangle has been
investigated by use of steady-state, time-resolved and
temperature-dependent photoluminescence (PL) spectroscopy.
1L-WS2 triangles synthesized by chemical vapor deposition
technique, exhibit non-uniform and uniform PL, respectively. The
non-uniform PL features, i.e. quenching and blue-shift in certain
regions, are attributed to structural imperfection and n-doping
induced by charged defects. Uniform emission is found to be
intrinsic, intense and non-blinking, indicating the high crystalline
quality of the sample. Moreover, the binding energy of the Aexciton is extracted from temperature dependence of PL
measurements,providinganevidenceofthelargeexcitoniceffect
in 1L-WS2. These superior optical properties make 1L-WS2
potentially important for optoelectronic applications such as novel
light-emittingdevicesandbiosensors.
POSTER: CM-22
Wei Ren
ShanghaiUniversity,China
renwei@shu.edu.cn
Multiferroic Materials from Rare Earth and Transition Metal
Oxide Perovskites
Multiferroicmaterialsconsistingofrareearthandtransistionmetal
oxides have very unusual structural and physical properties. In
contrast to the so-calledtypeImultiferroics,ferroelectricitymaybe
induced by magnetic ordering or by applying external fields. The
recentprogressontheexperimentalandtheoreticalstudiesoftype
II multiferroics is presented, with a focus on the perovskites
containing rare earth and transition metal elements. The rare earth
orthoferrites, rare earth titanate under strain, and rare earth
superlattices, are systematically studied to provide a broad
overview on their electronic, magnetic, and structural properties.
The recent experimental advances in single crystal growth by
optical floating zone method are also presented. First principles
investigations,eithersupportedbyexperimentalresultsorawaiting
for experimental verifications, are shown to offer useful guidance
fortheresearchofunconventionalmultiferroics.
POSTER: CM-23
Yanlong Wang* 1, Chunxiao Cong 1, Caiyu Qiu 1, Ting Yu 1,2
1
NanyangTechnologicalUniversity,Singapore
2
NationalUniversityofSingapore,Singapore
wang0710@e.ntu.edu.sg
Raman Spectroscopy Study of Lattice Vibration and
Crystallographic Orientation of Monolayer MoS2 under
Uniaxial Strain
Molybdenum disulfide (MoS2), a typical candidate of transition
metal dichalcogenides (TMDs) with layered structure has been
shown to possess unique optical, electrical and mechanical
properties. Here we report a systematic micro-Raman
spectroscopystudyofmonolayerMoS2undercontrollableuniaxial
tensile strain. Our experimental observation reveals that the
E_2g^1 optical phonon mode is sensitive to the in-plane uniaxial
strainwhiletheA1gmodeisinerttothestrain. When the strain is
sufficienthigh(i.e.>1%inthiswork)tobreakthelatticesymmetry,
such doubly degenerate E_2g^1 mode splits into two subbands,
named E_2g^(1+) andE_2g^(1-), according to their vibration
energies. Our polarization dependent Raman spectroscopy
investigationfurtherindicatesthatthepolarizationsofthescattered
light from these two subbands are linear and orthogonal.
Furthermore, the polar angles for the maxima and minima of the
intensities of these two subbands are strongly determined by the
crystallographic orientation relevant to the strain direction as
predictedbythetheoreticalanalysis.TheGrüneisenparameterfor
E_2g^1 phonon of monolayer MoS2 is also studied. Our findings
firmly demonstrate that Raman spectroscopy is a powerful probe
to monitor the amount of strain, identify the crystallographic
orientation,andinvestigatemechanicalpropertiesof2Dtransition
metaldichalcogenides,suchasMoS2.
Acknowledgement: This work is supported by the Singapore
National Research Foundation under NRF RF Award No.
NRFRF2010-07.
POSTER: CM-24
D. W. Wong*, M. Chandra Sekhar, W. L. Gan, I. Purnama and
W. S. Lew
NanyangTechnologicalUniversity,Singapore
dwwong1@e.ntu.edu.sg
Helical Domain Wall Dynamics in Cylindrical Nanowires for
3D-Data Storage
We recently reported three-dimensionalvortexmagnetizationwith
clockwise and anticlockwise orientations at the opposite ends in
relatively low aspect ratio cylindrical nanostructures [1]. The two
vortices gradually extend towards the center of the cylindrical
nanostructure and eventually are connected via a Helical domain
wall(DW).Itwasfoundthatthereisachangeinstrayfieldthatcan
be detected by GMR/TMR sensors as binary “1” and “0” at the
HelicalDW.Hence,HelicalDWscanbeusedtostoreinformation
in cylindrical nanostructures standing on the surface of a silicon
wafer,whichopenstheopportunityforthree-dimensional magnetic
memory devices such as race track memory [2]. Pinning sites
created along the race track can define the spacing between
consecutive DWs and also provide the stability to withstand
peripheral disturbances, such as thermal fluctuations or stray
magneticfieldsfromneighboringracetracks.
Here,wereportonthedynamicsofHelicalDWinNiFediametermodulated cylindrical magnetic nanostructures. The threshold
current density for Helical DW motion is found to be
and Helical DW velocity increases near linearly with
current density. For notch pinning site, the depinning current
density increases with increasing modulation length and
decreasingdiameter.ThisbehaviorisduetoacombinationofDW
deformation and rotation at the pinning site. In addition, NiFe
diameter-modulated cylindrical magnetic nanostructures were
fabricated by pulsed electrodeposition andfollowed by differential
chemical etching techniques. Magnetic force microscopy
measurements performed on the diameter-modulated cylindrical
magneticnanostructuresverifiestheexistenceoftheHelicalDWs.
Using magnetoresistance measurements, Helical DWs dynamics
intheNiFecylindricalmagneticnanostructuresunderexternalfield
andcurrentwillbepresented.
POSTER: CM-25
*Yafang Xu and Guojun Jin
NanjingUniversity,China
xyfnju@163.com
Controllable transformation between omnidirectional
transmission and reflection of pseudospin-1 Dirac fermions in
a Lieb optical superlattice
We theoretically investigate the energy spectra and transport
properties of the pseudospin-1 Dirac fermions in a Lieb optical
lattice with modulated periodic potential, where a crossover of
effectivemasscanbeachievedeasilybytuninglaserintensity.A
generaltheorybasedonthelow-energyHamiltonianisdeveloped
andcanbeusedtotreatoneormorebarriers.
Itisfound,forthemasslesspseudospin-1particles,thepresence
ofasuperlatticepotentialmodifiesthebandstructureandtransport
propertyremarkably,whicharedistinctivelydifferentfromthosein
graphene superlattices with pseudospin-1/2. In particular, there
exists a passband instead of extra Dirac points at the incident
energy corresponding to half of the potential step. The all-angle
Klein tunneling and the traditional Klein tunneling coexist in the
system,whichareveryrobustagainstthevariationsinthenumber
andwidthsofbarriers.However,forthemassiveones,bothofthe
tunneling phenomena are destroyed and an omnidirectional gap
arisesduetotheassociatedeffectsofmismatchedsublatticesand
multiple confined potentials. Consequently, a transformation from
omnidirectional transmission to reflection, accompanied with a
switch on/off of conductance can be realized easily by modifying
laser intensity, andthespectral region can beselective bytuning
the periodic potentials properly.
As a quantum simulator, the results in this cold-atom system
suggest some interesting applications in electronic or optical
devices.
POSTER: CM-26
Xuechao Zhai
NanjingUniversity,China
zxc@smail.nju.edu.cn
Photoinduced Topological Phase Transition in Epitaxial
Graphene
In epitaxial graphene irradiated by an off-resonance circularly
polarized light, we demonstrate a phase transition taking place
between band insulator and Floquet topological insulator.
Considering the competition between staggered sublattice
potential and photon dressing, we derive the dynamical energy
gap and phase diagram in the tight-binding approximation. It is
found that a threshold value of light intensity is necessary to
realize a Floquet topological insulator; at the phase boundary,for
each set of parameters, there is a special state with only onevalleyDiracconeclosed,buttheotherremainsopen;intheband
insulatingphase,onlyonevalleyworksneartheFermienergy,and
it could be switched to the other by reversing the polarization
direction of light. From these results, two electronic devices are
designed: one is an optical sensing np junction, where the
photodriven unusual intervalley tunneling exhibits a stronger
detectable signal than the intravalley tunneling; the other is a
topological field-effect transistor, where polarized light is used to
turnonorturnoffanonequilibriumcurrent.
POSTER: CM-27
Zhifeng Zhang*, Pinaki Sengupta
NanyangTechnologicalUniversity,Singapore
zh0063ng@e.ntu.edu.sg
The Plaquette State in the Anisotropic Shastru-Sutherland
Model
We have extended the phase diagram of the Shastry-Sutherland
model to include the spin anisotropy and obtained the stability
range of a generalised plaquette state. We also investigated the
dispersion of the quasi-particles within the generalised plaquette
phaseandfoundacriticallinearoundwhichapossiblecrossover
may occur between the plaquette valence bond state and
resonatingplaquettevalencebondstate.
POSTER: CM-28
Linfeng Sun*, Jiaxu Yan, Zhan Da, Zexiang Shen
NanyangTechnologicalUniversity,Singapore
s110016@e.ntu.edu.sg
Probing the Spin-Orbit Splitting in Single-Layer MoS2 by
Triply Resonant Raman Scattering
Based on the giant spin-orbitsplittinginsingle-layerMoS2,ithas
beenproposedthatcouldbeusedinspintronicdevices.However,
suchsplittinghasnotbeenstudiedeffectivelyexperimentally.This
work reports the valence band spin-orbit splitting in single-layer
MoS2 firstly, probed by the triply resonant Raman scattering
process.Wefoundthatupon325nmlaserirradiation,thesecond
order overtone and combination Raman modes of single-layer
MoS2 are dramatically enhanced. Such resonant Raman
enhancement arises from the electron-two-phonon triple
resonance via the deformation potential and Frohlich interaction.
As a sensitive and precise probe for the spin-orbit splitting, the
triply resonant Raman scattering will provide a new and
independentroutetostudythespincharacteristicsofMoS2.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 87
POSTER: CM-29
Cheng-Wei Wang*, Jian-Biao Chen, Ai-Zhen Liao, Wei-Dong
Zhu, Xu-Qiang Zhang
NorthwestNormalUniversity,China
cwwang@nwnu.edu.cn
Vertically aligned single-crystalline untra-thin CuO
nanosheets: low-temperature fabrication, growth mechanism,
and excellent field emission
Thekeypointforthesuccessfulapplicationsoffieldemission(FE)
devices is to develop the FE cold cathode with low turn-on and
threshold electric field, high FE current density, excellent FE
stabilityandlongoperatinglife.Inthisstudy,aneffective and onestep solvothermal process is developed to fabricate vertically
alignedultra-thinCuOnanosheetfieldemittersonCusubstrateat
lowtemperatureof90°C.Thepreparedverticallyalignedultra-thin
CuO nanosheets exhibit high-quality single crystalline structure
oriented along the [010] direction. The thickness and size of the
CuO nanosheets can be tailored by changing reaction duration
andtemperature.Onthebasisofexperimentalresults,apossible
mechanismfortheformationoftheverticallyalignedultra-thinCuO
nanosheets is speculated. Moreover, the prepared ultra-thin CuO
nanosheets exhibit excellent FE properties, a low turn-on electric
field of 2.19 V/μm and a high current density of 4.5 mA/cm2 at
8.23 V/μm can be realized from the optimized sample. More
importantly,theoptimizedsamplealsoshowsexcellentFEstability
with fluctuations within 2%. Based on temperature-dependent FE
measurement,thestableFEpropertycanbeattributedtothelow
local heating effects of sheet-like CuO emitters, originating from
theirsuperiorheatdissipationabilityandlowJouleheating.
POSTER: CM-30
Huichao Wang1, Haiwen Liu1,2, Cui-Zu Chang3,4, Huakun Zuo5,
Yanfei Zhao1, Yi Sun1, Zhengcai Xia5, Ke He2,3,4*, Xucun Ma2,3,4,
X. C. Xie1,2, Qi-Kun Xue2,3 and Jian Wang1,2*
1
PekingUniversity,China
2
CollaborativeInnovationCenterofQuantumMatter,China
3
TsinghuaUniversity,China
4
InstituteofPhysics,ChineseAcademyofSciences,China
5
HuazhongUniversityofScienceandTechnology,China
wanghuichao@pku.edu.cn
Crossover between Weak Antilocalization and Weak
Localization of Bulk States in Ultrathin Bi2Se3 Films
Wesystematicallystudyultrathintopologicalinsulatorfilmsof5nm
thickBi2Se3grownviamolecularbeamepitaxytechnique.Angleresolved photoemission spectroscopy data show that the Fermi
level lies in the bulk conduction band above the Dirac point. In
magneto-transportmeasurementsupto50Tesla,itisexcitingthat
thecrossoverbetweenweakantilocalizationandweaklocalization
of bulk states is clearly observed when the very high field B//
parallels the film plane. Moreover, different magneto-resistance
behaviors between B// ┴ I and B// // I configurations subtly reveal
the intrinsic spin-orbitcouplingeffectinBi2Se3 films.Asasmoking
gun, our work directly shows the quantum interference crossover
in the bulk states, which is of great importance for a
comprehensive understanding and potential application of
topologicalinsulators.
Three dimensional (3D) topological insulators (TIs) are band
insulators with gapless linear energy dispersion surface states.
Bi2Se3,Bi2Te3andSb2Te3areconfirmedastypical3DTIsdue
to their simplesingle surface Dirac cone and relatively large bulk
energy gap. These materials provide the possibility for the
observation of novel phenomena, including Majorana fermions,
magneto-electric effect, and quantum anomalous Hall effect, as
well as the potential applications in quantum computation. We
knowthatsemiconductorheterostructureconsistsofmaterialswith
different band structures and exhibits interesting quantum
behaviors, such as quantum Hall effect and fractional quantum
HalleffectinGaAs/AlxGa1-xAsheterostructures.Recently,normal
bandinsulator-3DTIorsemimetal-3DTIheterostructures,suchas
Sb2Se3-Bi2Se3 and Bi-Bi2Se3 (Bi2Te3) heterostrctures, have
attractedmuchinterestsincetheinterfaceoffersanewplatformto
study topological phase. However, up to now few experiments
have been carried on the heterostructure of two different TIs.
AccordingtoTIbandtheory,theexistenceofgaplesssurfacestate
isduetothetopologicalinvariantchangeintheinterfaceoftrivial
and non-trivial insulators. Nevertheless, it is still a question that
whatwillhappenwhengrowingonly1QLTIfilmonanothertype
ofTIthickfilms.Inthiswork,weepitaxiallygrew1QLBi2Se3on
19 QLs Bi2Te3 and form a 1 QL Bi2Se3 / 19QLs Bi2Te3
heterostructure.InsituARPESresultsshowthatthesurfacestate
oftheheterostructure1QLBi2Se3/19QLsBi2Te3issimilartothe
surface state of high electron doped Bi2Se3 film. Further ex situ
measurementsdemonstratethatthetransportpropertiesofBi2Se3
/ Bi2Te3 heterostructure, such as linear magnetoresistance (MR)
and weak antilocalization (WAL) of our Bi2Se3 / Bi2Te3
heterostructure behave totally different from that of pure Bi2Te3,
but similar to pure Bi2Se3. This experiment shows that the 1 QL
Bi2Se3 top layer dominates the transport properties of the
heterostructureandclearlydemonstratestheeffectofthesurface
stateonthetransportofaTI.StudyingonthisTI-TIheterostructure
mayprovideaplatformtoartificiallymodulatethebulkandsurface
electronic structures of TIs respectively and pave a way for
exploring potential applications in TI devices.
Doping charge carriers will causes the change of cuprates from
antiferromagnetic Mott insulators to high-Tc superconductors.
Continuouschangingofcarrierdensityisnecessarytounderstand
the nature of such phase transition, and thus, further our
understanding of cuprate superconductors. Electric field-effect
doping, especially with electronic double layer transistors (EDLT)
configurationwhichuseionicliquids(ILs)asthegatedielectrics,is
apotentialavenueforthisinvestigationandithasbeenshownits
effectiveness in inducing phase transition in strongly correlated
electron system. Owing to EDLT, superconductor-to-insulator
transition (SIT) has been observed in hole-doped cuprates La2xSrxCuO4andYBa2Cu3Oy.HereweuseEDLTtotunethecarrier
density in electron-doped cuprates Pr2-xCexCuO4 ultrathin films
and cause the sample evolves from an insulating state to a
superconducting state. Compared to the hole-doped cupratesthe
SIT in electron-doped system occur at critical sheet resistances
much lower than the pair quantum resistance RQ=h/(2e)2=6.45 kΩ,
suggesting the existence of fermionic excitations. Finite-size
scaling analysis indicates that this SIT is a quantum phase
transitionandthetransitionisgovernedbypercolationeffects.The
presentresultscouldbehelpfultostudySITbetweenelectron- and
hole-dopedcuprates.
POSTER: CM-32
Shengyuan A. Yang* 1, Hui Pan 2, and Fan Zhang 3
1
Singapore UniversityofTechnologyandDesign,Singapore
2
BeihangUniversity,China
3
UniversityofPennsylvania,USA,
KavliInstituteforTheoreticalPhysics,UniversityofCalifornia,
SantaBarbara,USA
shengyuan_yang@sutd.edu.sg
Dirac and Weyl Superconductors in Three Dimensions
We introduce the concept of 3D Dirac (Weyl) superconductors
(SC), which have protected bulk four(two)-fold nodal points and
surface Andreev arcs at zero energy. We provide a sufficient
criterionforrealizingthemincentrosymmetricSCs withodd-parity
pairing and mirror symmetry. Pairs of Dirac nodes appear in a
mirror-invariantplanewhenthemirrorwindingnumberisnontrivial.
Breaking mirror symmetry may gap Dirac nodes producing a
topological SC. Each Dirac node evolves to a nodal ring when
inversion-gaugesymmetryisbroken.ADiracnodemaysplitintoa
pairofWeylnodes,whenandonlywhentime-reversal symmetry is
broken.
POSTER: CM-33
POSTER: CM-31
Yanfei Zhao 1*, Cui-Zu Chang 2, Ying Jiang 4, Yi Sun 1, Huichao
Wang 1, Ying Xing 1, Yong Wang 4, Ke He 2, Xucun Ma 2, Qi-Kun
Xue 2, 3, and Jian Wang 1
1
PekingUniversity,China
2
InstituteofPhysics,ChineseAcademyofSciences,China
3
TsinghuaUniversity,China
4
ZhejiangUniversity,China
zhaoyanfei@pku.edu.cn
Demonstration of surface transport in a hybrid Bi2Se3/Bi2Te3
heterostructure
88 | The 8th OCPA International Conference on Physics Education and Frontier Physics
S. W. Zeng1,2, *, Z. Huang1, W. M. Lv1, N. N. Bao1,3, K.
Gopinadhan1, L. K. Jian1, T. S. Herng3, Y. L. Zhao1, H. J. Ma1,2,
P. Yang4, J. Ding1,3, T. Venkatesan1,2,5, Ariando1,2
1
NUSNNI-NanoCore,NationalUniversityofSingapore,Singapore,
2
DeptofPhysics,NationalUniversityofSingapore,Singapore,
3
DeptofMaterialsScienceandEngineering,NationalUniversityof
Singapore,Singapore
4
SingaporeSynchrotroLightSource,NationalUniversityof
Singapore,Singapore
5
DeptofElectricalandComputerEngineering,NationalUniversity
ofSingapore,Singapore
shengweizeng@gmail.com
Electric field-induced two-dimensional superconductorinsulator transition in an electron-doped cuprate
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 89
Energy and Environmental Physics
POSTER: EN-01
Arbi Dimyati1, Pudji Untoro1, Didim Prihadi2
1
SuryaUniversity,Indonesia
2
CVEiche,Indonesia
arbi.dimyati@surya.ac.id
Hybrid Gasoline / LPG Converter
AnefficientandlowcostLPGConverterforapplicationin4stroke
engines has been designed, fabricated andtested. Thekey parts
oftheconverterarevacuumvalveandgasinjector.Itcanbeeasily
installed into almost all the gasoline engine systems, such as
moped and small electrical generator, with all cylinder sizes. The
installation does not change the original design of the engine
system.Theengineequippedwiththeconvertercanworkindual
fuel operation modes, gasoline and lpg mode. The role of
switching between gasoline and lpg mode is taken by a solenoid
valve, which operates at 12Voltand about 5Watt of power. The
switchcan easily be activated even during engine operation.The
engineefficiencyincreaseupto4timeshigherthanwithgasoline.
The acceleration behaviour at higher speed is improved. Long
distance test on an 100ccm motorcycle engine have proved that
the consumption about 100 km per-1kg lpg. At lpg mode the
emissionoftoxicgasesandsootdecreasesconsiderably.
POSTER: EN-02
Dongliang Chao, Xinhui Xia, Jilei Liu, Jianyi Lin, Hong Jin Fan,
Ze Xiang Shen,
NanyangTechnologicalUniversity,
Singapores120055@e.ntu.edu.sg
A V2O5/Conductive-Polymer Core/Shell Nanobelt Array on
Three-Dimensional Graphite Foam: A High-Rate, Ultrastable,
and Freestanding Cathode for Lithium-Ion Batteries
Developmentofadvancedrechargeablelithiumionbatteries(LIBs)
is one of the most important challenges of modern
electrochemistry. V2O5 has been long regarded as a promising
cathode material but it suffers from poor conductivity and longcycle structural stability. In order to pursue LIBs with both high
energyandpowerdensitiesaswellaslonglifespan,inthiswork,
we design and construct an smartly integrated system by
combining V2O5/(Poly (3,4-ethylenedioxythiophene), PEDOT)
core/shell nanobelts array (NBA) and self-supported ultrathin
graphite foam (UGF) as a light-weight, binder-free positive
electrode.BecauseofthedirectgrowthofV2O5nanostructureson
UGFandsurfaceengineeringduetothemesoporousPEDOTthin
shell, our integrated electrode shows superior and evidently
improved Li-ion storage performance, with higher specific
capacities,high-ratecapabilityandcyclingstabilityascomparedto
bare V2O5 NBA without PEDOT coating and other V2O5 based
nanostructure electrodes. The achieved high performance may
push the promising V2O5 nanostructure LIB electrode an
importantstepforwardintopracticalapplications.
POSTER: EN-03
Dionisius Hardjo Lukito
InstitutTeknologiBandung,Indonesia
dionisius11@live.com
Development of a Solar Based Thermoelectric Generator
System
Nowadays,oneofourgreatestconcernsistheglobalenergycrisis.
Worldenergyconsumptionhasbeenmultipliedbyfivetimesover
1950 – 2010, and it is still expected to be rising due to its
significanceinourlife.Theimportanceofenergyhasdrivenusto
excel in alternative energy. Through this research, we expect to
discover an efficient solar based thermoelectric generator (TEG)
system andtocompareperformanceofthedesignedsystemwith
existing references and models. In the end, this research is
90 | The 8th OCPA International Conference on Physics Education and Frontier Physics
expectedtobeaninnovationinsolarradiationutilization,bytaking
advantage of TEG's ability to convert solar‟s thermal energy into
electricity.
Our problems are how to design an efficient solar based TEG
system and how efficient is the system's performance in real
operational condition? This research comprises modelling of
module‟s performance due to temperature difference across the
module‟s sides (ΔT),andtestingsysteminrealfieldcondition.
To understand module‟s nature, observation of its behaviour upon
exposure of ΔT is required. Opposedtothe real fieldcondition in
which the thermal exposure is indeterminate, hot water as
controllable source of thermal energy is used here. Through this
process, electricity production were modelled as mathematical
functions of ΔT, which explained system‟s nature under thermal
exposure, i.e. its tendency to produce more electricity when
exposed to higher ΔT. However, the models could not predict
outputaccuratelyonfieldtests.
System designing focuses on optimizing ΔT and using thermal
energy efficiently. Solar radiation collector and thermal reservoirs
of high thermal conductivity were applied to achieve optimum
performance. To assist thermal energy transfer and utilization,
insulationandthermalpastewereapplied.
Three major apparatuses have been tested with variations on
number of applied module(s), metal that is used as the hot
reservoir, and/or application of insulation. Apparatus (App.) A
utilized one module, 4 mm copper as the hot reservoir, without
insulationonthesystem,whileApp.BisidenticalwithApp.A,with
an addition of insulation system. Five modules in series circuit
were implemented in App. C, with 2 mm aluminium hot reservoir
andinsulationonit.
Through all tests, App. C produced highest voltage of 400 mV;
greatest current was 63 mA (App. A); greatest power was 12.39
mW, with efficiency of 0.0418% (App. B). Averagely, highest ΔT
was experienced by App. A (5.2°C), followed by highest current
productionof45.5mA.Duetohigheramountofappliedmodules,
App.Cproducedgreatestvoltageaveragelyof306.7mV.Interm
of average power production, App. B excelled with 6.015 mW,
equivalenttoanaverageefficiencyof0.023%.
System'sefficiencyisrelativelylow,duetomodule'slowreference
efficiency and efficiency calculation which is based on collector
area, that is greater than the effective power generating area.
System requires hot and cold reservoir with high thermal
conductivity; well-designed solar radiation collector, preferably a
parabola; further development of the module, and; sufficient
amountofmodules,toperformmoreefficiently.
POSTER: EN-05
POSTER: EN-07
Ir. Matheus Souisa*, M.Si
PattimuraUniversity,Indonesia
txsenwitzne@yahoo.co.id
Pudji Untoro*, Amir Hamzah, Arbi Dimyati
SuryaUniversity,Indonesia
pudji.untoro@surya.ac.id
Mapping of Lateritic Nickel Deposit Using Resistivity Method
at Piru, Western Seram Regency, Moluccas Province,
Indonesia
Characterization of Reactor System Generator Using Low
Grade Bioethanol Fuel
Geophysical research has been done by using resistivity method
at Piru, Western Seram Regency, Moluccas Province. This
research aims to find out the existence of lateritic nickel deposit
and resource estimation of lateritic nickel deposit in the research
area. The area is 110.000 m2 with a total of 7 lines of survey,
whose spaces between the measurement points were 10 meters
andthelengthofeachlinewas210meters.
ThedatawereprocessedbyusingRes2Dinvsoftwaretogenerate
informationaboutthetrueresistivityin2-D section. Then the data
were analyzed and correlated to the results of petrography
analysis, geochemical analysis, and geological surface data.
Petrographyanalysiscandeterminethecharacteristicofminerals
in rocks, geochemical analysis can determine the element
contents of rocks, and geological surface data prove the
informationabout theexistenceoflateriticnickelanditsresistivity
value in the research area. Furthermore, the 3-D modeling was
made using the Geosoft to estimate the volume of lateritic nickel
deposit.
The result of samples analysis indicate that the average total
content of elements in all lines for Co, Fe, and Ni were 0,02%,
4,70%, and 1,29%. The value of lateritic nickel resistivity in this
area ranged from 40-150 ohm meter for limonite zone and from
150-400 ohm meter for saprolite zone. From result of the 3-D
combinedsections of limonite and saprolite, itcan beknown that
themeasurablepotentialmodelforlateriticnickelwas326.673m3,
so the total of estimated lateritic nickel resources in the research
area was 658.572,77 tons at the concentration of 1,29%. The
measurable potential amount of lateritic nickel covers only the
research area.
POSTER: EN-06
Paksi Raganata, GDE
ParahyanganCatholicUniversity,Indonesia
paksiraganatagde@gmail.com
POSTER: EN-04
The Effects of Plastic Addition to Asphalt Mixture Flexibility
Dra. Ni Ketut Lasmi
InstitutTeknologiBandung,Indonesia
k.lasmi@yahoo.com
The research is about analyzing the effects of adding plastic into
an asphalt mixture. This research itself is based on a preceding
research about plastic-asphalt, a new type of asphalt mixture
whichhasapurposetosolvetheplasticwasteandasphaltquality
problem.
The Design of Mixing Device of Biogas and Air to Produce
Electrical Power
Biogasisarenewableenergysourcethatcananswertheneedof
electricity. It is an alternative energy that ismadebymakinguseof
cow manure through anaerobic digestion process. In order to
produce electric energy from biogas there are several steps that
mustbedone.Firsttherateofflowthebiogasismeasuredusinga
flowmeter,measuredmethanitisthen flowedintotheventuripipe
andgoestoamixingdevicewhereitwillmixwithairandbecome
biogas steam. When the biogas steam comes out of the device
andheadstothefurnaceroom,therateflowisthesamesothe
difference in pressure between the biogas and air can be
measured. In the furnace room the biogas steam will spin the
generatorwhichcausesenergyconversionfrombiogastoelectric
energy.
Theproblemwhichissuspectedtobethemaincauseofeffectsto
the flexibility is the nature of the plastic. Plastics are plastomers,
not elastomers, and are rigid in nature. This leads to further
suspicion that the asphalt itself will contradict it's essential
characteristic as a flexible pavement, becoming a rigid pavement
instead.
To analyze the effects, three quality control parameters which
representstheflexibilityoftheasphaltwillbetested.Thetestitself
will be done on five samples with various proportions of plastic
withinasphalt.
Bioenergy in the form of heat or electricity can be produced by
usingsweetsorghumdirectlyasafuelbyconvertingittobioetanol
usingfermentationprocess.Themainprocessesforutilizingthese
bioetanol normally mixing with maximal 85% bioetanol content.
Another technique are possible with gasification via a physical or
chemical conversion process to a secondary gaseous fuel,
followed by combustion in an engine, boiler or turbine. In the
present study we report on the characterization of a new reactor
system generator using low grade bioethanol fuel (80%) on the
performance of generator with pure bioethanol from sweet
sorghum.Weobservedthatinsitupowerenginestabilitywithload
more than 70% leads to the substantial change of electricity
frequency and decreasedstability during operation. Based on the
resultsobtained,thatapplicationofgeneratorinstalledwithreactor
system affected not only using bioethanol but also petroleum.
Reactor behaviour distribution are strongly determined by
concentration of bioethanol or bioethanol/water ratio and the
electrical power. This present study shows interesting application
resultsincomparisonwithreactorsystemprocessingofbioethanol
as functions of the electric power, influencing the stability of the
operation.
POSTER: EN-08
V. Sankaran*, T. S. Mulaudzi and N. E. Maluta
UniversityofVenda,SouthAfrica
vaith.sankaran@univen.ac.za
Evaluation and testing of different theoretical models for the
estimation of solar radiation in the Vhembe District, Limpopo
Province of South Africa.
Many countries in Africa are experiencing energy crisis. In South
Africa(SA)about90%ofelectricityisgeneratedbycoalalthough
some small percentage of energy supply from other resources
such as biomass, hydroelectric, nuclear energy, etc. Electricity
generated by coal is non-renewable and not friendly to the
environment. The provision of supply of electricity in an
environmentally sustainable manner remains a major challenge
across Africa. To date the bulk of power is generated from fossil
fuels which are carbon intensive. Solar radiation is the useful
source of renewable energy. It South Africa is one of the
developingcountrieswithsomeregionsrichinsolarenergy,wind
energy,etc.,foruseinreplacementoffossilfuels.CurrentlytheSA
government policy is projected on increasing the use of different
renewable energy technologies. Vhembe is one of the ideal sites
forimplementingtherenewablesolarenergyforruraldevelopment.
Globalsolarradiation(H)isanimportantparameterfordesigning
and installation of the renewable solar energy technologies.
BecauseofthelimitedmeasureddataavailableofHinmostofthe
countries, especially the developing countries, is an estimated
using a variety of model. Both the temperature and sunshine
dependentmodelswereevaluatedforthefourselectedstationsin
Vhembe Limpopo Province. The available regression coefficients
andsunshinehoursreceivedfromSouthAfricanWeatherServices
(SAWS) have been used in both Angstrom and Gracia based
models. Hargreaves and Samani model as well as Gracia based
models used the minimum and maximum air temperature data.
Boththetemperatureandglobalsolarradiationdatawereobtained
from the Agricultural Research Council (ARC), South Africa. The
results revealed that the temperature and sunshine dependent
models are suitable for the prediction of global solar radiation in
theNorthernAridBushveldclimate.Thesemodelshaveexhibited
thetendencytoperformsuitablywellsincetheirrootmeansquare
error(RMSE)wasfoundtobelessthan4%.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 91
POSTER: EN-09
Photonics and Photovoltaics
Jin Wang*, Jianyi Lin, Zexiang Shen
NanyangTechnologicalUniversity,Singapore
Wang0844@e.ntu.edu.sg
POSTER: PH-01
Self-assembly of Honeycomb-like MoS2 Nanoarchitectures
Anchored into Graphene Foam for Enhanced Lithium Ion
Storage
A facile P123-assisted route has been rationally designed to
synthesize 3D honeycomb-like MoS2 nanoarchitectures anchored
into 3DGF. The as-obtained 3DGF provided a novelsubstrate for
the nucleation and subsequent growth of honeycomb-like MoS2
nanoarchitectures,
in
which
the
hierarchical
MoS2
nanoarchitectures are well-defined by self-assembly of ultrathin
nanosheets.TheseuniqueMoS2HCs@GFarchitectureelectrode
exhibits greatly improved Li+-storage properties owing to its high
surface area, massive porous hierarchical structure, highly
conductive substrates directly as current collector, and 3D
interpenetrating structure. 3D honeycomb-like MoS2@GF display
a high discharge capacityof1235.3mAhg-1atacurrentdensity
of 200 mA g-1, retaining 85.8% of the initial reversible capacity
after60cycle.Theseresultsclearlydemonstratetheadvantageof
the MoS2 HCs@GF and we believe that the 3D honeycombstructured MoS2@graphene foam is very promising for further
broad applications in electronics, sensors, catalysis, transistors
andsupercapacitor.
POSTER: EN-10
Changrong Zhu *, Ignacio Minguez Bacho, Dongliang Chao,
Xinhui Xia, Hongjin Fan
NanyangTechnologicalUniversity,Singapore
s120004@ntu.edu.sg
Cu2O-Cu Core-shell as Anode for Lithium-ion Battery
Cu2O nanowires were fabricated through a simple anodization
process. After heat treatment, the hybrid core-shell structure was
madeandtheCu2OnanowireswerecoveredbyathinlayerofCu.
The protective Cu layer provide better passage for the electrons
and ions. The core-shell structure provide an ultrahigh cyclability
andratecapability.
C. La-o-vorakiat*, Y. Tian, T. Wu, C. Panagopoulos, J.-X. Zhu,
Haibin Su, and Elbert E. M. Chia
NanyangTechnologicalUniversity,Singapore
lchan@ntu.edu.sg
Interface-Induced Magnetic Coupling in Multiferroic /
Ferromagnetic Bilayer
By use of optical pump-probe measurement, we study the
relaxation
dynamics
of
a
muliferroic-ferromagnetic
TbMnO3/La0.7Sr0.3MnO3 (TMO/LSMO) bilayer. The relaxation
dynamics of both layers are wellseparated in time allowing us to
investigate themagneticcoupling across the bilayer.We observe
thatthe relaxation dynamics of the individual layers in the bilayer
sample are the result of the interplay between the intrinsic
magneticorderandtheinducedinterfacialeffect.Ourdatasuggest
theexistenceofinducedferromagneticorderintheTMOmagnetic
orderintheLSMO
References:
POSTER: PH-04
Che-Wei Huang*; Jian-An Yao, Hsuan-Yin Chen, Chao-Kuei
Lee
NationalSunYat-SenUniversity,Taiwan
chester3151@gmail.com
Two-Photon Absorption Effects and Its Characteristics of
Terahertz Radiation
C.La-o-vorakiat,Y.Tian,T.Wu,C.Panagopoulos,J.-X.Zhu,H.B.
Su,andElbertE.M.ChiaAppl.Phys.Lett.104,141602(2014)"
THz radiation from photoconductive antenna (PCA) is important
duetoitsefficiency.TheoutputTHzpowerfromaPCantennais
stronglycorrelatedwiththephotoexcitedcarrierdensityandwillbe
saturatedwhenpumpedharder.
POSTER: PH-02
In this work, the characterization of the Two-photon absorption
(TPA) induced extra photocurrent for Terahertz (THz) radiation
underhighpeakpowerisstudiedtheoreticallyandexperimentally.
Liang Cheng*, Chan La-o-vorakiat, Chi Sin Tang, Saritha K.
Nair, Bin Xia, Lan Wang, Jian-Xin Zhu, Elbert E. M. Chia
1)NanyangTechnologicalUniversity,Singapore
2)LosAlamosNationalLaboratory,USA
lcheng003@ntu.edu.sg
POSTER: PH-05
Temperature-Dependent Ultrafast Carrier and Phonon
Dynamics of Topological Insulator Bi1.5Sb0.5Te1.8Se1.2
Bi1.5Sb0.5Te1.8Se1.2 (BSTS) is a type of topological insulator,
whichisaninsulatorinbulkbutsurfacestatesaregapless[1,2].
In this work, we took optical pump-probe and optical pumpTerahertzprobedataonBSTScrystaltoanalyzethedynamicsof
phonons and charge carriers. The ultrafast dynamics were
obtained as a function of temperature ranging from 10K to 300K,
as well as fluence ranging from 1 uJ/cm2 to 10 uJ/cm2. In
additional to the coherent optical phonon mode found in other
topologicalinsulators[3,4],acousticphononmodewasobserved
in our experiment. We also observed phonon softening and the
temperaturedependenceofcarrierlifetimeinBSTS.
References:
1)J.E.Moore,Nature464,194(2010).
2)M.Z.Hasanet.al.Rev.Mod.Phys.82,3045(2010).
3)Y.W.Liet.al.Appl.Phys.Lett.97,171908(2010).
4)N.Kumaret.al.Phys.Rev.B83,235306(2011).
POSTER: PH-03
Daniele Cortecchia*, Herlina A. Dewi, Sabba Dharani, Tom
Baikie, Cesare Soci, Nripan Mathews
NanyangTechnologicalUniversity,Singapore
DANIELE001@e.ntu.edu.sg
2D Hybrid Perovskites for Photovoltaic Application
During the last years, lead-based 3D perovskites with general
formula (CH3NH3)PbX3 have attracted great interest in the
photovoltaic research community due to their close to ideal
properties: band-gap of 1.55 eV, high absorption coefficient, low
excitonbindingenergyandhighelectronandholediffusionlength.
Moreover, this material can be solution processed at low
temperature, and low cost devices with power conversion
efficiency exceeding 16% have been recently demonstrated. This
92 | The 8th OCPA International Conference on Physics Education and Frontier Physics
makes lead perovskites
highly attractive for future
commercialization. However, the high lead content of this
sensitizerrepresentamajorobstacletoitslargescaleproduction,
duetoissuesrelatedtotoxcicity,pollutionandbio-accumulationin
the eco-system. Therefore, lead replacement with metals more
environmentally friendly is highly desirable; bi-dimensional
perovskites with general formula (CH3NH3)2MX4 based on
transition metals are interesting green alternatives to the lead
based perovskite however, to the best of our knowledge, studies
ontheirapplicationaslightharvestersinsolarcellshavenotbeen
reported yet. The following study reports on the synthesis,
characterisationandopticalpropertiesof2Dperovskitesandtheir
potential integration in to solar cell devices.
James Lourembam 1*, Amar Srivastava 2, Chan La-o-vorakiat
1
,T. Venkatesan 2, Elbert Chia 1
1
NanyangTechnologicalUniversity,Singapore
2
NationalUniversityofSingapore,Singapore
james1@e.ntu.edu.sg
Metallic Features in Novel VO2(B) Phase Thin Films as
Revealed by Terahertz Time Domain Spectroscopy
Vanadium oxide can adopt different polymorphic structures and
amongst them is the metastable monoclinic VO2(B) phase. We
use time-resolved terahertz spectroscopy to probe the
conductivities of novel VO2(B) thin films. The experimental data
show that the Drude conductivity model can account for the
observed behaviour at higher temperatures whereas at low
temperatures <240 K, it shows insulating behaviour. Our results
reveal the presence of metal to insulator transition in VO2(B)
system.
POSTER: PH-06
C Liyong Jiang*, Tingting Yin, Hailong Hu, Zexiang Shen,
Xiangyin Li
1.)NanjingUniversityofScienceandTechnology,China
2.)NanyangTechnologicalUniversity,Singapore
jly@mail.njust.edu.cn
Enhanced Super Resolution Obtained by Nanoscale Solid
Immersion Lenses with Dark-field Illumination
Thesuper resolution beyondAbbe diffractionlimit is now being a
persistently hot topic in modern optics and nanophotonics. To
break through the Abbe diffraction limit, several attractive and
novel techniques have been proposed and extensively studied in
the past couple of years, including flat perfect lens based on
negative refraction effect, scanning near field optical microscope
(SNOM)basedonnanoscaleapertureortips,sub-wavelengthlight
focusingbyopticalsuperoscillations,andthemicroscopeimaging
based on nanoscale solid immersion lenses (nSIL) or optical
microspheres.Forinstance,opticalmicrospheres(refractiveindex
is ns) with plane-wave illumination can generate near-field focal
spot or far-field photonic nanojet with lateral resolution slightly
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 93
beyond λ/2ns in theory and produce impressive capability to
distinguishassmallas50nm-scalenanostructuresinexperiment.
Alternatively,nSILwithlensedplane-waveilluminationcanpresent
near-field focal spot with about 18.6% reduction in the focal spot
width as compared to the optical microspheres. In the present
study, we report a new super-resolution technique based upon
nSIL with dark-field illumination. We have systematically
investigatedthe influence of numerical aperture (NA) of dark-field
source, location of nSIL, and configuration of nSIL on final full
width at half maximum (FWHM) of focal spot. The simulation
results show that nSIL with dark-field illumination can generally
produce near-field focal spot of about 12~16% reduction in the
focalspotwidthincomparisonwithlensedplane-waveillumination,
while the dark-field source with relatively small inner NA, a slight
move of the nSIL center to dark-field source, and an optimal
diameterofnSILareusefultofurtherdecreasetheFWHMoffocal
spot. In particular, when nSIL with a diameter of 1250 nm and
center location shift of λ towards dark-field source, a near-field
focal spot with FWHM of about 111 nm can be achieved
corresponding to illumination wavelength of 400 nm. This is
apparently better than previous work which reports a minimum
near-field focal spot with FWHMof about 144 nm. The enhanced
super resolution in this work is believed to be attributed to the
combinationofangular-spectrumtechniquewithnear-fieldimaging
technique.
POSTER: PH-07
Ng Yi Ming*, He Mi, Lee Jung-Kun, Chia Ee Min, Elbert
1.)NanyangTechnologicalUniversity,Singapore
2.)UniversityofPittsburgh,USA
p120013@e.ntu.edu.sg
Terahertz Conductivity of Indium Zinc Oxide Films
Indiumzincoxide(IZO),asaclassoftransparentconductingoxide
materials, has great potential in applicationssuch as photovoltaic
devices and flat panel displays. In this work, the optical
conductivity of IZO film and IZO film with different ratios of Ag
nanoparticles (e.g. 5wt%, 10wt%) were investigated using
terahertz (THz) time-domain spectroscopy at different
temperatures(10K-300K).Themeasuredresultswerewellfitted
theoreticallyanddiscussed.
POSTER: PH-08
Kelvin J. A. Ooi*, Lay Kee Ang
SingaporeUniversityofTechnologyandDesign,Singapore
kelvin_ooi@sutd.edu.sg
Graphene Optoelectronic Plasmonic Devices
Graphene plasmonics emerges as a new platform for
optoelectronic devices. Owing to its highly reconfigurable
permittivity-function and large confinement factor, graphene
plasmonicsshowspotentialinultracompact,subwavelengthactive
opticaldeviceswithhighmodulationcontrast.Weshowtheuseof
graphenenanoribbonplasmonicwaveguidestodesignnanometrescale modulators that have modulation contrast exceeding 30dB.
These graphene nanorribon waveguides are further adapted into
thedesignsofactivesplitternetworksaswellaslogicgatedevices.
One of the main challenges of graphene plasmonics is the poor
plasmon-excitationefficiencybyplaneelectromagneticwavesdue
tothelargewave-vectormismatch.Westudiedthepossibilitiesof
in-situ generation of graphene plasmons by electrical excitations
through aloof-scattering and inelastic tunneling. These excitation
schemesareadvantageousintheirpotentiallysmalldevicesizes,
andarehighlyintegratableintochip-scaleplatforms.
1. K. J. A. Ooi, H.S. Chu, L.K.Ang, P.Bai,"Mid-infrared active
graphene nanoribbon plasmonic waveguide devices," JOSA B
30(12),3111-3116(2013).
2. K. J. A. Ooi, H. S. Chu, P. Bai, L. K. Ang, "Electro-optical
grapheneplasmoniclogicgates,"OpticsLetters39(6),1629-1632
(2014).
94 | The 8th OCPA International Conference on Physics Education and Frontier Physics
POSTER: PH-09
correspondingfouriertransformpatterns,showninFig.4d,4eand
4f,disclosestheirrotationalsymmetry.
POSTER: PH-13
Riza Muhida*, Hiroaki Okamoto
1)SuryaUniversity,Indonesia
2)OsakaUniversity,Japan
riza.muhida@surya.ac.id
This work will provide a guidance for the large-area and fast
production of periodical and quasiperiodical PhC structures with
highquality.
Wen-Long Yan*; Yung-Hsiang Lin; Chung-Lun Wu; Chih-Hsien
Cheng; Kai-Chen Lin; Gong-Ru Lin; and Chao-Kuei Lee
NationalSunYat-senUniversity,Taiwan
hushinpeace@hotmail.com
A Novel Method to Find The Optimum Texture Substrate of
Thin Film Solar Cells Based on Calculation of The Power
Spectrum Density of Texture Substrate.
Fig.2HexagonalPhCswithdifferentperiodandcells(a-e)andthe
diffractionpattern(f)
Investigation Of Nonlinear Absorption Of PECVD Growth
Graphene Using Femtosecond Z-Scan Technique
Fig.3 Ten-fold quasicrystalline structures (a-c), FFT diagram (d)
anddiffractionpattern(e)
In this work, nonlinear absorption coefficient of PECVD growth
Graphene was characterized using femotosecond Z-scan
technique.Thetwophotonabsorption(TPA)coefficientashighas
10-5 (m/W) was observed. In addition, wavelength dependence
and possible mechanism of tremendously large TPA coefficient
werediscussedaswell.
The light trapping in thin film poly-Si layer by using textured
substrateisoneoftheimportanttechnicalissuesforachievement
ofhighperformanceofsolarcells.Currently,mostmethodstofind
theoptimaltexturestructureofsubstrateforthinfilmsolarcellsis
usingtryanderrortechnique,wherewemustspendalotoftimeto
makeseriesofexperimentsofmanytypeoftexturesaswellasto
spendmaterialforfabricationsolarcellsusethesetextures.
In this paper we propose a novel technique to find the best
structure of texture based on calculation of power spectrum
density(PSD)oftexturebeforeweusethesetextureforfabrication
ofsolarcells.
We used an atomic force microscopy (AFM) to characterize the
texture in 3D, based on raw data of AFM, we calculate the PSD
andaveragewidthofroughnessmodulationthenwecalculatethe
average slope of surface texture. Based on this slope calculation
wefoundthatslopeofthesubstratetextureproportionalwithlight
trapping performance as well as solar cells performance from
results of experiment. Based on calculation and experiments, we
findthatthetexturedZnO/Ag/SnO2/glasswithslopeof0.08yields
themaximumconversionefficiencyforJscandVoc.
POSTER: PH-10
XiaoHong SUN
ZhengzhouUniversity,China
iexhsun@zzu.edu.cn
Optics Design and Fabrication of Periodical and Quasiperiodical Photonic Crystals by Using a Single-prism
Interferometer
Photoniccrystals(PhCs)arenanostructuredmaterialsinwhichthe
dielectric constant is periodically modulated on a length scale to
achieve the desired wavelength of operation. PhCs can control
and manipulate the light propagation by photonic localization and
photonic band gaps. The photonic band gaps exhibiting in PhCs
are very attractive for three-dimensional (3D) high-capacity data
storage,polymerwaveguides,reflectivedisplays,andotherrelated
uses. The fabrication of PhCs has always been of great interest.
Previously established methods of making PhCs include
semiconductor microfabrication, colloidal crystallization, tightly
focusedlaserbeamscanning,two-photonpolymerization,andselfassembly of colloidal spheres. Recently, a new technology,
holographic lithography, was reported and has drawn much
attention. Espectially the fabrication setup of a single refracting
prismisthoughttobeverysimple,stable,andeasytoadjust.
Compared to periodic PhCs, quasicrystals (quasiperiodical PhCs)
have higher point group symmetry and are more favorable in
achieving complete band-gaps. They exhibit long-range aperiodic
order and rotational symmetries that fall outside the traditional
crystallographic classification schemes. Furthermore, because of
thehigherrotationalsymmetryofthequasicrystals,theband-gaps
are more isotropic and thus are more favorable in achieving
complete band-gaps than conventional PhCs. In recent years, a
growing number of researchers are engaged in the research on
quasicrystals.
In this report, asingle-prism interferometer is usedto design and
fabricate periodical and quasi-periodical PhCs. The experimental
configuration is shown in Fig.1. Hexagonal PhC structures with
differentperiodsandcellsarerealizedinphotoresistfilms,shown
inFig.2a,2b,2c2dand2e.Thediffractionpattern,showninFig.2f,
reveals the hexagonal symmetry. Ten-fold rotational symmetrical
quasicrystals have been also fabricated and shown in Fig.3a 3b
and3c.Fig.3dandeshowsFFTtransformationdiagramandtenfold symmetrical diffraction patterns. Onthe other hand, 12-, 18-,
and 24-fold quasicrystals are designed in Fig.4a, 4b and 4c. The
Fig.1Thesystematicconfiguration
Fig.4 12-, 18-, and 24-fold quasicrystals (a-c) and
correspondingFourierTransformpatterns.
the
POSTER: PH-11
Huanxin Xia*, Meng Zhao, Chan La-o-vorakiat, Elbert E. M.
Chia
1)NanyangTechnologicalUniversity,Singapore
2)NationalUniversityofSingapore,Singapore
hxia1@e.ntu.edu.sg
Optical Conductivity Studies on Bi2Te3 & Single-layerGraphene in Terahertz Range
Therealpartoftheopticalconductivityofthetopologicalinsulator
Bi2Te3, single-layer-graphene (SLG), and Bi2Te3/SLG composite,
allgrownonp-dopedSisubstrate,wereobtained usingTerahertz
time-domain spectroscopy (THz-TDS), in the temperature range
15 – 300 K and frequency range 0.3 - 3 THz. Both the Drude
response,andthreeRaman-infraredactiveopticalphononmodes,
were observed: Eg(1) ~ 1 THz, A1g(1) ~ 1.7 THz and A1u ~ 2.7
THz.[1,2] The Drude contribution from SLG in the Bi 2Te3/SLG
composite was surprisingly suppressed above 80K, whose origin
was attributed to the competition of Bi2Te3 and SLG at different
temperature.Besides,A1g(1)modeshowsananomalousphonon
hardeningwithincreasingtemperature,whichmeansthree-phonon
processdominatesinthiskindofsample.
POSTER: PH-14
Huakang Yu 1,5*, Wei Fang 1, Xiaoqin Wu 1, Xing Lin 1, Limin
Tong 1, Weitao Liu 2, Aimin Wang 3, Y. Ron Shen 2,4
1
ZhejiangUniversity,China
2
FudanUniversity,China
3
PekingUniversity,China
4
UniversityofCalifornia,USA
5
NanyangTechnologicalUniversity,Singapore
huakang@ntu.edu.sg
Single Nanowire Optical Correlator
References:
Recentlynanowireshaveemergedaspromisingbuildingblocksfor
nanophotonic circuits and devices. A single nanowire optical
correlator (SNOC) is demonstrated here for ultrafast pulse
characterization[1]. The operation principle of SNOC is based on
imaging of the second harmonic generation (SHG) from a
cadmium sulfide nanowire by counter-propagating guided pulses.
The SHG spatial image can be readily converted to the temporal
profile of the pulses, with only an overall pulse energy of 2 µJ
neededforaclearimageof100fspulses.Webelievethatsucha
correlator will find its wide applications of on-chip ultrafast optical
technologyinfuture.
1)J.Appl.Phys.111,054305(2012).
Reference:
2)Appl.Phys.Lett.96,153103(2010)
H.Yu,W.Fang,X.Wu,X.Lin,L.Tong,W.Liu,A.Wang,andY.R.
Shen, "Single nanowire optical correlator," Nano Lett., Article
ASAP(2014).
POSTER: PH-12
Hongyi Xu*, Xihang Shi, Fei Gao, Handong Sun, Baile Zhang
NanyangTechnologicalUniversity,Singapore
hxu1@e.ntu.edu.sg
The Experimental Realization of a Three-Dimensional Thermal
Invisibility Cloak
Inspiredbytheconceptofopticalinvisibilitycloak,wepresentthe
first experimental realization of a three dimensional thermal
invisibility cloak, which can hidean object inconductive heat flux
by recovering the distortion of eternal temperature field at three
dimensions.Thevolumeratiobetweentheinvisibilitycloakandthe
hidden object is 0.06, indicating that an invisibility cloak with the
thickness of 100 μm is enough to hide a spherical object with the
diameterof1cm.Thecloakiscapabletofunctioninbothtransient
andthermalequilibriumstate.
POSTER: PH-15
Xu Zhang
ZhengzhouUniversity,China
zhangxubetter@gmail.com
High-efficiency Solar Cell on Double-Heterostructure
Nanopillar Arrays
This paper presents a theoretical analysis of light trapping
properties of InP/InGaAs/InP double-heterostructure nanopillar
arrays(NPAs)solarcells.Duetothepotentialforlowercost,antireflection and light-trapping properties compared to conventional
thinfilmdeviceandsemiconductornanowirearrays(NWA),NPAs
are regarded as promising candidates for next generation
photovoltaic devices. However, much attention has been focused
on NWA based solar cell recently, the potential of optical
absorption in NPAs used in photovoltaic devices has rarely been
investigated. Because nanowires usually have small lateral
dimension and require metal catalyst, these often degrade the
material quality and restrict their applications. The growths of
nanopillarsfabricatedbyChang'sgroupinBerkeleyareconducted
at425°C,temperaturesevenlowerthanthatoftypicalVLSgrown
nanowires, making the process ideal for silicon-CMOS
processes.[1]Particularly,theircatalyst-freepropertiesmakethem
ideal for photonic device application, which are sensitive to
damage from temperatures above 450 °C and also to metal
contamination.
The absorptance of NPAs with the optimized parameters covers
the wavelength range from 310nm to 2600nm, which maintains
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 95
above 80% up to wavelength of 2000nm. This wavelength range
encompassesabout95%ofsolarenergy.Wehavedemonstrated
that the optical absorption can be greatly enhanced in NPAs,
especially for the weak absorption in the long wavelength regime
(λ>925nm) of single crystalline InPnanoneedle,duetothesmooth
index transition at the air-array interface and doubleheterostructure used. The short-circuit current of NPAs with the
optimizeddesigncanachieve62.4mA/cm2,whichismuchhigher
thanitsnanoneedlearrays(NNAs)andthinfilmlayercounterparts
with the same thickness. In addition, our double-heterostructure
NPAs solar cells outperform similar cells based on core-shell
nanowire structure. The reported maximum value of short-circuit
current of core-shell InP nanowires with filling factor of 57% was
13.7mA/cm2,[2]thatvaluewasincreasedto24.6mA/cm2foraxial
InP nanowire with filling factor of 72%, which was the best result
everobtainedfornanowirebasedsolarcells.[3]
References:
1)F.Ren,K.W.Ng,H.Sun,andC. Chang-Hasnain,Appl.Phys.
Lett.102,012115(2013).
2) H. Goto, K. Nosaki, K. Tomioka, S. Hara, K. Hiruma, J.
Motohisa,andT.Fukui,ApplPhysExpress2,035004(2009).
3) J. Wallentin, N. Anttu, D. Asoli, M. Huffman, I. Aberg, M. H.
Magnusson, G. Siefer, P. Fuss-Kailuweit, F. Dimroth, B.
Witzigmann, H. Q. Xu, L. Samuelson, K. Deppert, and M. T.
Borgstrom,Science339,1057(2013).
Physics Education
POSTER: PE-01
Agus Jarwanto
CansiusCollege,Indonesia
Ajar.jati@gmail.com
Cultivate, Build Perseverance Character by Physics Learning
Project
Physics is not easy subject for most students. The effort of
interesting physics learning is almost done. The constructivism in
learningsupportthedevelopmentofcooperativelearningmethod.
Learning project is one of constructivism learning models. The
learning project has a lot of pluses. The positive implication of
learningprojectisthedeepcharacterofstudents.Thecharacteris
of main value which is very use full for the future leaders. The
valueswhichdevelopinstudentsamongothersgoodcooperation,
smart and creative work, perseverance, etc. Besides the positive
impactforthestudents,theknowledgeandthefutureteacherare
alsoenrichedthroughthelearning.
POSTER: PE-02
Sheh Lit Chang*, Leiju Qiu, Nidhi Sharma
NationalUniversityofSingapore,Singapore
shehlit@gmail.com
Effectiveness of Pre-lecture Reading Quiz on Academic
Achievement in Calculus-Based Introductory Physics Course
Attendinglecturewithapreparedmindismoreeffectiveinstudy.
However, most of the students could not read the lecture notes
before they attend each lecture. To encourage our students to
readconscientiouslybeforeclassthroughoutthewholesemester,
weintroducedpre-lecturereadingquizasaformativeassessment
in calculus-based introductory physics course for engineering
students. A quiz was delivered before the start of each new
chapter via the Integrated Virtual Learning Environment (IVLE),
which includes a few conceptual multiple choice questions.
Meanwhile, we also conducted a mid-semester survey to obtain
informationonthestudents'preparationforthepre-lecturequiz.To
seehoweffectivethismethodis,weperformedat-testtofindout
how students' test / exam scores were dependent on their preclassreadingbycontrollingseveralothervariables.Weusedafew
factors to proxy the effort students put in the pre-lecture reading
which includesstudents' participation/ performance scores in the
pre-lecture reading quizzes, time taken to read the lecture notes
and whether they attempt the quizzes alone or with friends. The
controlling variables were grade point average (GPA) before this
semester,numberofmodulestakeninthesemester,involvement
in co-curricular activities (CCA) and year of study. The results
showedthatstudentswhoputineffortinreadingthelecturenotes
and attempted the pre-lecture quizzes generally have better
performanceintestandexams,whichimpliesthatourmethodwas
effective. With little effort to modify the conventional lectureteachingmethodbyimplementing the pre-lecturereadingquiz,we
reaped great improvement in the students‟ learning. The results
also showed that students with higher previous GPA, and who
chose relatively more modules in the same semester could get
higherscoreinbothexamandtest.Interestingly,thestudentswho
were active in CCA could also get higher scores, and the juniors
performedbetterthantheirseniors.
POSTER: PE-03
Ivan Irawan
ParahyanganCatholicUniversity,Indonesia
irawan.ivan@gmail.com
Fun Science in Your School: Yay or Nay?
According to the PISA study of science literacy, Indonesia is
rankedatthebottomend.Thisreflectshowpoorscienceliteracyin
Indonesia is. To cope with the issue, we introduced a science-
96 | The 8th OCPA International Conference on Physics Education and Frontier Physics
learningmethodthatencouragesstudentstolearnsciencethrough
funandexperimentalprojectsinseveralhighschoolsinBandung,
Indonesia.
A survey was then conducted to measure how effective and
suitablethemethodisfortheeducationsysteminIndonesia.The
surveywascarriedoutonstudentsandteacherswhoarefamiliar
withthismethodorwhohaveexperiencedthemethodthemselves.
Although the method has few drawbacks, the result showed that
themethodaffectedthestudentspositivelyandsuggestedthatthe
method might be a good way to elevate science literacy in
Indonesia.
POSTER: PE-04
Jutri Taruna
SuryaSchoolofEducation,Indonesia
jutri.taruna@stkipsurya.ac.id
At-Risk Students in Physics Education: A Qualitative Study
The purpose of this qualitative study was to investigate the
learning difficulties of at-risk students enrolled in Physics
InstructionalDesigncourseinSpring2013.
Ourdatashowedthatat-riskstudentshadnotpossessedmastery
ofIndonesianlanguage,especiallyinreadingandwriting.Thelack
of language skills had hampered students‟ progress in class.
Students struggled with reading assignments, home works and
projects.
Oneoftheprojectsinthecoursewasdesigningaphysicslesson
plan.Toensurethatstudentswerewellpreparedforthetask,they
were required to take general Physics course prior to taking this
course.
However, we found that at-risk students were still struggling with
thephysicsconcept.Thesefactorstogetherwithpoorstudyskills
weremajorobstaclesat-riskstudentsfacedintheirstudies.
POSTER: PE-05
*Dave Lommen
HwaChongInstitution,Singapore
dave@hci.edu.sg
Improving student engagement and understanding through
Just-In-Time teaching and ConcepTests
There is a saying that “college is a place where a professor‟s
lecture notes go straight to the students‟ lecture notes, without
passing through the brains of either. There is even scientific
evidence that brain activity is lower during class or lectures than
during sleep (Poh et al., 2010). It would thus appear that a large
part of students‟ college time is effectively wasted.
Aseparateproblem,moreparticulartothestudyingofphysics,is
that students are often well able to solve physics problems
mathematically, but that they just as often lack a proper
understandingoftheunderlyingconcepts.Asexaminationsinclude
moreandmorequalitativeexplanationsofeverydayapplications,a
deeperunderstandingoftheconceptsbecomesmoreimportant.
Iwillherediscusstwoweaponstoattacktheseproblems.Thefirst
isJust-in-TimeTeaching(JiTT)andthesecondistheteachingof
concepts through the use of ConcepTests. I discuss the
implementation of these two tools in one of the top schools in
Singapore. There will be a particular focus on the teaching of
quantummechanicstoagroupoftalentedstudents.
JiTT is a pedagogical strategy that uses feedback between
classroom activities and work that students do at home in
preparation for the classroom meeting (Marrs et al., 2003). The
goals areto increase learning during classroom time, to enhance
studentmotivation,toencouragestudentstoprepareforclassand
toallowtheinstructortofinetunetheclassroomactivitiestobest
meet the students‟ needs.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 97
For this year‟s quantum-mechanics course, students were tasked
to read ahead in preparation for the lecture. They further had to
answer three basic-understanding questions and provide the
lecturerwithinformationonwhatpartsofthematerialwereunclear.
I would use the students‟ answers to the “reading quiz” to prepare
the lecture. As a result, less lecture time would be spent
discussingtopicsthatwerecleartoall,whereasmoretimewould
bespentondifficulttopics.
ConcepTests are multiple-choice questions that require an
application of knowledge, with little or no use of mathematical
formulas.Studentsareforcedtothinkcriticallyaboutthequestions
beforeanswering,thentodiscusswiththeirneighboursforanew
roundofanswering.Implementedproperly,theConcepTestsgive
the teacher immediate feedback on misconceptions that exist
among the students, which can be addressed immediately or
revisited at a later time.
Plasma Physics
POSTER: PL-04
POSTER: PL-01
Yingbin Zhu*, Lay Kee Ang
SingaporeUniversityofTechnologyandDesign,Singapore
zhuyingbin@gmail.com
Shi-Jun Liang and Lay Kee Ang
SingaporeUniversityofTechnologyandDesign,Singapore
shijun_liang@mymail.sutd.edu.sg
A General Quantum Model for Charge Transport In The Space
Charge Limited Regime
ConcepTestsareanintegralpartofmyTutorialsandIalsoinclude
them in my Lectures. Many students highlight them as their
favourite part of the Tutorial and they claim that they help them
better understand the concepts. Crouch & Mazur (2001) showed
that such conceptual understanding in turn allows for a better
score on regular assessments. ConcepTests further train 21st
centurycompetenciessuchascriticalthinkingandcommunication.
In the classictheory,twolaws,Child-Langmuir(C-L)lawandMottGurney (M-G) law, are established to descripe the space charge
limited current through the vacuum and solid, respectively.
Recently,researchfindinghasconfirmedanewscalingofC-Llaw
in the quantumregime.Soitisofinteresttoinvestigatetheclassic
M-G law also shows a new scaling when the transport length is
undernanoscaleregime.Inthiswork,wedevelopageneralmodel
and establish a new scaling of voltage Vg and gap spacing D. A
smooth transition from classic regime to quantum regime is also
demonstrated for space charge limited current in the solid and
vacuum.
POSTER: PE-06
POSTER: PL-02
Monica Fanny Asmarianing Tyas
St.HendrikusSeniorHighSchoolSurabaya,Indonesia
monica_asmarianingtyas@yahoo.co.id
Chia-Hsun Wu*, Jeng-Dau Wang, Yu-Wen Chen
NationalChung-ShanInstituteofScienceandTechnology,Taiwan
jaywu0916@gmail.com
Physics in Reality: Learning Viscosity through Ice Cream
Physics Learning Model by using Integrated and Project
Based Learning for Senior High School Students
Design and Simulation of a Novel 4-Port Coupled Cavity KaTWT
ThelessonsthatarereceivedbyIndonesianhighschoolstudents
tend to befragmented (split).Students arestill difficultto see the
big picture of the relationship of various disciplines without
knowingitsapplicationindailylife.
Theviscosityisaphysicsconceptthatisdifficulttobeunderstood
by students. That‟s why the integrating learning is made to unite
severalsubjectsintheformofvisitationtoPTCampinaIceCream
Industry Surabaya. The subjects which are integrated in this
programarePhysics,ChemistryandBiology.
Inthisresearchtheproblemstatementishowstudentslearnabout
viscosity in their daily life. So this research shows the students
learning process in a project to understand viscosity and other
conceptsinothersubjectswhichisintergratedlearning.
In three subjects which are integrated (physics, chemistry and
biology), the teachers determine the concepts that can be
combined for the students of XI Science class. Designing the
project-based learning, including choosing the place and date of
observation, and explaining viscosity concept and other concpets
to students are parts of project preparation. Before the visitation
theteachersaskthestudentstoeaticecreamandsearchforice
cream recipe.
Duringavisittotheicecreamfactory,studentsdoactivitiessuch
as the making of ice cream, knowing the composition of the ice
creamandhowtopackageit.
After the visit, the students make ice cream based on the recipe
they have chosen, and then eat the ice cream together. At this
time, the evaluation is conducted through the oral questions.
Duringthepresentationsession,studentsareabletoconnectthe
concepts of the 3 integrated subjects (physics, chemistry and
biology)involvedintheprocessoficecreammaking.
TheResultofthisresearchisstudentlearnaboutviscosity,colloid
emulsion, about ice cream effectto the body, and about value of
lifethroughmakingtheicecream.
AttenuatorsandseversarecommonlyusedinhighgainTWTsto
prevent oscillation. The attenuators in coupled cavity TWT are
implementedbydepositingRFabsorbingceramicmaterial,sothat
itbecomesdifficulttopreciselysimulatethenonlinearbeam-wave
interactionduetoreducedwavelengthinattenuators.Inthispaper,
a novel 4-port coupled cavity TWT is proposed to replace
attenuators and severs. The simulation is modeled with the 3-D
electromagnetic particle-in-cell code CST and effective oscillation
suppressioncanbeobtainedwithour4-port design.
POSTER: PL-03
Tingting Yin*, Albert Wan, Hailong Hu, Liyong Jiang
NanyangTechnologicalUniversity,Singapore
YINT0006@e.ntu.edu.sg
Gap Plasmons Generated from Single Silver Nanowires and
Gold Nanobeams
In this work, we investigate the one-photon photoluminescence
from a hybrid and orthogonal configuration consisting of a Ag
nanowireandaAunanobeamwithadielectricspacer(3nm-12nm)
that supports a localized resonance known as the gap plasmon
mode. At the intersection part, we investigate the enhanced
photoluminesence of Au nanobeam and a new peak( gap
plasmon).Wealsomeasurethecorrespondingdark-fieldspectra,
in which the new peak has almost the same peak position with
respecttophotoluminesence.Itrevealsthatthegapmodeisareal
plamonic mode existing in such a hybrid structure. Besides, the
gap plasmons shows distance and polarization dependence
according to the dark field and photoluminescence experimental
results. These observations were supported by FDTD simulation
results.
Novel Scaling Law of Space Charge Limited Current
Space-charge-limited(SCL)electronflowdescribesthemaximum
current density allowed for steady-state electron beam transport
across planar, cylindrical, or spherical diode [1][2]. These current
densities aregivenbythewell-knownChild-Langmuir(CL)lawand
Langmuir-Blodgett(LB)law.Extensivestudieshavebeendoneto
revise the 1D classical CL law to multi-dimensional models,
quantum regime and ultrafast time scale. Base on a transit time
model [3], it is found that the LB solutions for the SCL current in
both cylindrical and spherical diodes may be approximated by a
novel scaling law using the electric field on the cathode surface
and the anode-cathodespacingoverawiderangeofparameters.
Minor empirical corrections to the above scaling yield fitting
formulas that are accurateto within 2.5 percentfor a large range
0.002 < Ra/Rc < 30000. A physical explanation of this scaling is
alsogiven.Ansingleelectroncapacitormodelincludingthespace
charge effect yields the LB solutions even in the Coulomb
blockade regime for a nanogap [3][4], where the electron number
may be inthe single digits. It isfound thatthere is athreshold of
voltage (Vth) equals to one-half of the single electron charging
energyforelectroninjectionassumingzerobarrierattheinterface.
Forvoltageslightlyhigherthanthethresholdvoltage,thereisonly
one electron inside the gap within one transit time, and the timeaverage of the single electron induce current may be equal or
higherthantheclassicalCLlawandLBlawinplanar,cylindrical,
orsphericaldiode.ThetransittimefrequencyisintheTHzrange
whenthegapdistanceisabout100nm.Thismodelisalsoextent
for electron injection intosolid,the SCL current for trap-filled and
trap-freematerials are re-derived[5]. Lastly, we extend our study
to multi-dimensional model for a “non-symmetry” gap with a
protrusivecathodeandaflatanode[6].Twotypesofconditionsto
reachtheSCLcurrentflowareconsidered.Thefirstoneissourcelimitedtype,whichistheelectronfieldemissionemittedaccording
to the different cathode field on the sharp tip including space
charge field, non-uniform work function on the tip surface is also
considered. The second typeCLlaw-likeemission,whichistofind
theprofileofSCLcurrentinordertodrivethecathodeelectricfield
to zero at all locations. For both types, we conclude that nonuniformSCLcurrentisrequiredforsuchnon-symmetry geometries.
Huge current enhancement over the CL law on the tip apex is
observed due to the geometrical effect. The models constructed
here will be useful for accurate modeling of emission physics in
many codes used in non-neutral plasma, high power microwave
sourceandhighcurrentbeams.
References:
1)C.D.Child,Phys.Rev.(SeriesI)32,492(1911).
2)I.LangmuirandK.B.Blodgett,Phys.Rev.22,347(1923).
3)Y.B.Zhu,P.Zhang,A.Valfells,L.K.Ang,andY.Y.Lau,Phys.
Rev.Lett.110,265007(2013).
4)Y.B.ZhuandL.K.Ang,Appl.Phys.Lett.98,051502(2011).
5)Y.B.ZhuandL.K.Ang,J.Appl.Phys.110,094514(2011).
6)Y.B.ZhuandL.K.Ang,Submited.
The conclusion of this research is students learn about viscosity
through integrated learning which is designed in form of project
based learning. Students can understand the concept of an
integrated through the lessons included in this model. Students
can do the exploration, assessment, interpretation, and synthesis
ofinformationtoproducevariousformsoflearningoutcomes.
98 | The 8th OCPA International Conference on Physics Education and Frontier Physics
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 99
POSTER: PL-05
Zhuang Juan, Wu Dong Jiang
DalianUniversityofTechnology,China
Zhuangjuan6688@163.com
Numerical Simulation of SiH4 concentration Effects on
Densities of Important Species for Silicon Film Deposition at
Atmospheric Pressure
Based on a two-dimensional fluid model, the characteristics of
homogeneous discharges of H2 diluted SiH4 and Ar at
atmospheric pressure is numerically investigated. The primary
processesofexcitation,ionizationandsixteenreactionsofradicals
withradicalsinSiH4/H2/Ardischargesareconsidered.Theeffects
of SiH4 concentration on densities of species (e, H, SiH3) are
analyzed.Thesimulationresultsshowthatthehighestdensitiesof
e,H,SiH3arecorrespondingtohighrelevantSiH4concentration.
In the use of microcrystalline silicon films deposited with
Ar/SiH4/H2 discharge process, SiH4 concentration is a very
importantparameter,whichdeterminesboththestructureandthe
film deposition rate.Therefore,study of SiH4 concentration effect
on main deposited particle (including electron, SiH3, H) density
distribution is very important. The electron density distribution
plays a very important role in the reaction gas. When SiH4
concentration increases from 0.005% to 0.1%, the densities of
electron, SiH3 and H atom are all increased. The peak electron
density increase from 6.31×1011cm-3 to 3.48×1012cm-3, SiH3
density increases from 9.08×1011 cm-3 to 9.73×1013cm-3, and
atom H density increases from 2.82 × 1012 cm-3 to 3.69 ×
1013cm-3.SinceSiH3particlesaremainlymicrocrystallinesilicon
thin film deposition particles, and H atoms in the deposition of
microcrystalline silicon film also play an important role in the
process, which not onlysignificantly affect the deposition rate but
also affect the crystal orientation of microcrystalline silicon films,
we can concludesthat increasing SiH4 concentration leads to an
improvementoftheµc-Si:Hfilmsgrowing.
This work is supported by the Liaoning Province Natural Science
Foundation(GrantNo.201202037).
Quantum Information & Interdisciplinary
Sciences
temperature case. For the SGL sample with sufficiently large Δ,
however,thespikeisabsent.Thus,anabsenceinthespikecould
actasapossiblesignatureofthepresenceofSGLeffects.
POSTER: QIS-01
POSTER: QIS-04
Aiai Jia
ShanxiUniversity,China
jiaaiai1988@163.com
Chang-Jian Kwong
NationalUniversityofSingapore,Singapore
cqtkcj@nus.edu.sg
Influence of losses on the wave-particle duality
Optical Simulation of Bosonic-Fermionic in Quantum Walk
with Photons Distinguishability
We theoretically investigate the influence of losses on the waveparticledualityinaMach-Zehnderinterferometer.Balancedlosses
(equal loss on the two paths) have no effect on the visibility and
predictability(alsothedualityrelation),whileunbalancedlossesdo
haveinfluenceonthem.Iftheunbalancedlossesoccurinsidethe
interferometer,thelosseshaveaneffectonboththevisibilityand
predictability,whilethelosseshavenoeffectonthedualityrelation.
Iftheunbalancedlossesoccuraftertheinterferometer,thelosses
have no effect on the visibility, but do have an effect on the
predictability (also the wave-particle duality), which can lead to a
result that the duality relation exceeds 1, P^2+V^2>1. The
influence of losses can be eliminated by exchanging the two
detectors or the two inputs (one photon and the vacuum) of the
interferometer and then averaging the two results. Consequently,
we have the visibility, predictability, and duality relation
P^2+V^2<=1independentoftheunbalancedlosses.Theobtained
P and V for the unbalanced losses in the two paths do not
represent the original predictability and visibility, and the result of
P^2+V^2>1 does not mean the “violation” of the original duality.
POSTER: QIS-05
POSTER: QIS-02
Hua Lu
HubeiTechnologyUniversity,China
lvhuahg@163.com
*Koh Chee Yeong1, Kwek Leong Chuan2
1
NanyangTechnologicalUniversity,Singapore
2
NationalUniversityofSingapore,Singapore
marvelnature@gmail.com
Security of Two-way Quantum Key Distribution against
Detector-Side-Channel Attacks
Entanglement of a 2-qubit system coupled to a bath of
quantum spin glass
We study the quantum entanglement (concurrence) of a 2-qubit
system coupled to a small spin glass bath of 2 to n ≥ 4 qubits. The
bath is described by the quantum XX Heisenberg model with
random J coupling and varying magnetic field h. We look at the
dynamicsofthesteadystateaverageconcurrenceforthesystem
andobtainageneralformulatodescribetheconcurrencewithJ=
0andh=0fornbathsites.Thephysicsof2-qubitsystemcoupled
withnbathsitesforJ=0isanalyticallydescribedforsmalln.The
resultforlargenwasnumericallyfoundtobequalitativelysimilar.
For small fluctuation in J, a mean steady state average
concurrenceofabout0.5isobtained.
POSTER: QIS-03
Chee Yeong Koh
NationalUniversityofSingapore,Singapore
marvelnature@gmail.com
Probing Quantum Spin Glass Like System with a Double
Quantum Dot
We study the ground state properties of a 4-qubit spin glass like
(SGL)chainwithprobesattheendofthechainandcompareour
results with the non-spin glass like (NSGL) case. The SGL is
modeled as a spin chain with nearest neighbor couplings, taking
on normal variates with mean J and variance Δ2. The
entanglement between the probes is used to detect any
discontinuity in the ground state energy spectrum. For the NSGL
case, it was found that the concurrence of the probes exhibits
sharptransitionswheneverthereareabruptchangesintheenergy
spectrum. In particular, for the 4-qubit case, there is a sudden
changeinthegroundstateenergyatanexternalmagneticfieldB
of around 0.66 (resulting in a drop in concurrence of the probes)
and 1.7 (manifest as a spike). The latter spike persists for finite
100 | The 8th OCPA International Conference on Physics Education and Frontier Physics
Quantum Walks has many useful applications in different fields
suchasquantumcomputation,quantuminformationandcomputer
science.Usinganallopticalsetup,DeNicolaet.al.havestudied
the influence of particle statistics i.e. bosonic or fermionic on
quantumwalks.Here,weinvestigatehowphotondistinguishability
can affects the optical simulation of a four particle discrete
quantum walks by apply a delay in one of the input port of the
setup. We observe that the probability distribution of all possible
outputstates after afourstep quantum walk is dependent onthe
photon distinguishability and particle statistics. From the
measurementprobabilityofseveralspecificoutputstates,onecan
estimatethephotondistinguishabilityoftheinputstatesaswellas
the particle statistics. A comparisons with the probability of
classical random walk shows that the photon distinguishability
doesnotaffectthe"quantumness"oftheQuantumWalks.
In a two-way deterministic quantum key distribution (DQKD)
protocol, Bob randomly prepares qubits in one of four states and
sends them to Alice. To encode a bit,Aliceperformsanoperation
oneachreceivedqubitandreturnsittoBob.Bobthenmeasures
the backward qubits to learn about Alice's operations and hence
thekeybits.Recently,weprovedtheunconditionalsecurityofthe
final key ofthis protocol in the ideal device setting.In this paper,
weprovethattwo-wayDQKDprotocolsareimmunetoalldetector
side channel attacks at Bob's side, while we assume ideal
detectors at Alice's side for error testing. Our result represents a
step forward in making DQKD protocols secure against general
detectorsidechannelattacks.
POSTER: QIS-06
Meutia Wulansatiti Nursanto
UniversitasKatolikParahyangan,Indonesia
meu.101294@gmail.com
The Application of Radioactive Decay in Positron Electron
Topography
PET (Positron Electron Topography) is a mean of scanning body
tissues for any malfunctions by taking advantage of positronemmitingradioactivedecay.Thepositronsemittedbyaradiotracer
injectedintothebodywillcollidewiththeexistingelectronsinthe
body, thus positron-electron annihilation occurs. This annihilation
emits two gamma ray photons that will be detected by a ring
detectorlocatedaroundthebed.Thedetectordetectstwogamma
photonsthatreachtheringatthesametimebutoriginateopposite
of each other. A 3D image of the body tissue will then be
constructed based on these detections by means of computer
analysis.AlthoughPEThastheabilitytoproduce3Dimages,one
ofitsdownsideisthattheradionuclidesusedinradiotracershave
extremelyshorthalf-lives.Thisforceshospitalstohavecyclotrons
nearbytosupplythemwiththenecessaryradionuclides.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 101
POSTER: QIS-07
Lukas Knips, Wieslaw Laskowski, Tomasz Paterek, Anna de
Rosier, Christian Schwemmer, Minh Cong Tran*, Harald
Weinfurter.
NanyangTechnologicalUniversity,Singapore
cmtran@ntu.edu.sg
Quantum Entanglement without Correlations
All entangled bipartite quantum states are correlated. However,
extrapolationtothemultipartitecasedoesnothold.Wefirstshow
theoretically that it is always possible to erase correlations
between an odd number of qubits, while this is not possible
betweenanevennumberofthem.Thisallowsustoconstructan
infinitefamilyofstatesthatexhibitgenuinetripartiteentanglement
without tripartite correlations. We then develop experimentally
friendly criterion in order to detect this entanglement and perform
experiments demonstrating entanglement without correlations in
polarisation entangled three photon mixed states.
POSTER: QIS-08
Hailong Wang*, Derek Y. H. Ho, Wayne Lawton, Jiao Wang,
Jiangbin Gong
NationalUniversityofSingapore,Singapore
hailong.china@gmail.com
Kicked-Harper Model versus On-Resonance Double-Kicked
Rotor Model: From Spectral Difference to Topological
Equivalence
Recentstudieshaveestablishedthat,inadditiontothewell-known
kicked-Harpermodel(KHM),anon-resonance double-kickedrotor
(ORDKR)modelalsohasHofstadter'sbutterflyFloquetspectrum,
withstrongresemblancetothestandardHofstadterspectrumthat
is a paradigm in studies of the integer quantum Hall effect. This
workmakesdetailedcomparisonsbetweenthesetwomodels.We
show that there exist simple extensions of the KHM and ORDKR
model (upon introducing an additional periodic phase parameter)
such that the resulting extended KHM and ORDKR model are
actually topologically equivalent, i.e., they yield exactly the same
Floquet-band Chern numbers and display topological phase
transitions at the same kick strengths. A theoretical derivation of
thistopologicalequivalenceisprovided.Theseresultsarealsoof
interest to our current understanding of quantum-classical
correspondence considering that the KHM and ORDKR model
have exactly the same classical limit after a simple canonical
transformation.
Statistical Mechanics and Nonlinear Physics
POSTER: SM-04
POSTER: SM-01
Muhammad Yusuf
UniversitasNegeriGorontalo,Indonesia
myusuf@physicist.net
Shu-Chiuan Chang *1, Lung-Chi Chen 2, Weigen Yan 3
1
NationalChengKungUniversity,Taiwan
2
FuJenCatholicUniversity,Taiwan
3
JimeiUniversity,Taiwan
scchang@mail.ncku.edu.tw
Independent sets on the Sierpinski gasket
The number of independent sets is equivalent to the partition
function of the hard-core lattice gas model with nearest-neighbor
exclusion and unit activity. We study the number of independent
sets m_{d,b}(n) on the generalized Sierpinski gasket SG_{d,b}(n)
on the generalized Sierpinski gasket SG_{d,b}(n) at stage n with
dimensiondequaltotwo,threeandfourforb=2,andlayerbequal
to three for d=2. Upper and lower bounds for the asymptotic
growth constant, defined as z(SG_{d,b})=lim_{v →∞} ln
m_{d,b}(n)/vwherevisthenumberofvertices,ontheseSierpinski
gaskets are derived in terms of the numbers at a certain stage.
The numerical values of these z(SG_{d,b}) are evaluated with
more than a hundred significant figures accurate. We also
conjecture upper and lower bounds for the asymptotic growth
constant z(SG_{d,2}) with general d, and the approximation of
z(SG_{d,2})whendislarge.
POSTER: SM-02
Cheryl Abundo*, Erika Fille Legara, Christopher Monterola,
Lock Yue Chew
NationalTechnologicalUniversity,Singapore
Cherylde001@e.ntu.edu.sg
Neutrino On Gauge Supersymmetry
InthispaperstudythegeometryofsupersymmetryEinstein-YangMills, supersymmetry field theories on space time, extra gauge
supersymmetry Higgs Boson-Fermion of Neutrino in cosmology
andtheearlyuniverse.
POSTER: SM-05
Yuanjian Zheng*, Dario Poletti
SingaporeUniversityofTechnology&Design,Singapore
yuanjian_zheng@sutd.edu.sg
Quantum Heat Engines
We study the performance of a quantum Otto cycle driven by
anharmonic trapping potentials. This family of potentials
possesses a simple scaling property that allows for analytical
insightsintotheefficiencyandworkoutputofthecycle.Thusfar,
existingstudiesonQuantumthermodynamiccycleshaveprimarily
focusedonharmonicsystems,withstudyofanharmonicpotentials
limited.Here,weshowthatwhileboththemeanworkoutputand
efficiencyoftwoOttocyclesindifferenttrappingpotentialscanbe
made equal, the work probability distribution will still be strongly
affectedbythedifferenceinstructureoftheenergylevels.Lastly,
we also perform a comparison of quantum Otto cycles in various
physicallyrelevantscenariosandfindthatincertain instances,the
efficiencyofthecycledrivenbyanharmonicpotentialsaresuperior
to harmonic ones.
Estimating Travel Demand In Transportation Networks
Interactions and movements in urban systems are dependent on
their transportation networks. For these systems to function
efficiently, there is a need to build a robust network. We present
herehowwecancouplelanduseandnetworkstructuretomodel
the travel demand of stations in a transportation network. This
givesusinsightsastohowtransportationnetworksshouldevolve
withchanginglandusepatterns.Asaninitialcasestudy,weapply
the model to the Singapore Rapid Transit System RTS. We find
thatconsideringthedegreecentralityofthenetworkandusingthe
grossplotratioasthepotentialmeasureofhowlikelyacommuter
willbeattractedtotraveltospecificareas,thepredictedvaluesof
the model has a correlationof0.70 withactualdata.
POSTER: QIS-09
Chih-Hung Wang and Yu-Huei Wu*
1) Spacetimebookshop,Taiwan
2) National Central University,Taiwan
yuhueiwu@gmail.com
How can one observe gravitational angular momentum
radiation near null infinity?
Westudythegravitationalenergyfluxandtheangular-momentum
fluxofthetwistingvacuumsolutionsofEinsteinfieldequationsat
nullinfinity.Bytransformingtheoriginaltwistingvacuumsolutions
tosatisfyBondicoordinateconditionsintheasymptoticalregionof
the null infinity, we obtain the Bondi-Sachs news functions and
also find the relationship of how does the angular momentum
contribute to the news functions. We further calculate the
gravitational angular-momentum flux of the twisting space-times
fromKomar'sintegralofangularmomentum.Thisstudyprovidesa
theoretical basis to understand the correlations of gravitational
radiations neararotatingdynamicalhorizonandnullinfinity.
102 | The 8th OCPA International Conference on Physics Education and Frontier Physics
POSTER: SM-03
Kalai Kumar Rajagopal*, Sithi Vinayagam Muniandy.
UniversityofMalaya,Malaysia
kkrajagop@gmail.com
Two-mode Bose-Einstein Condensate Subjected to Noise and
Dissipation.
We studied the dynamics of a two-mode Bose-Einstein
Condensate (BEC) subjected to phase noise and particle loss
within the corrected mean-field model. Discrepancies with the
mean-fieldmodelisobservedforthemediumandsmallpopulation
imbalance. Coherence and purity of the system are substantially
alteredbyphasenoise,whiledissipationaloneplaysminorrolein
thereductionofboth.Theconcurrentpresenceofdissipationwith
phasenoiseisfoundtoenhancebothcoherenceandpurityinthe
system.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 103
Submission by High School Students
POSTER: HS-01
Jau-Tung Chan*
RafflesInstitution,Singapore
jautung@singnet.com.sg
Interdisciplinary Sciences
An Investigation into the Interaction and Resulting Shapes of
a Thin Liquid Jet Impacting a Soap Film, and Either
Penetrating Through it or Merging with it
Thisstudyinvestigatestheinteractionbetweenathinliquidjetand
a soap film. Two regimes of interactions are observed: the first
occurs when surface tension forces are small, where the jet
passes through the film and is deflected by it (termed refraction);
thesecondoccurssurfacetensionforcesarelarge,wherethejet
mergeswiththefilmandformsverticalundulationpatternsonthe
filmsurface(termedabsorption).Theseregimesarecausedbythe
interplay between the inertia of the jet, and the surface tension
forcesofboththejetandthefilm.Constructingasetup thatuses
hydrostatic pressure to create the jet, the interaction was
photographed and the shapes ofthe jet were obtained via image
analysis.Beinganewly-investigatedphenomenon,however,there
were few models in literature to describe this interaction. This
study thus proposes a revised theoretical model and empirically
verifiesitspredictions.Theresultsshowthattherevisedmodelis
abletoaccuratelyquantitativelypredict(a)theboundaryofthetwo
regimes, (b) the deflection of the jet when it refracts, and (c) the
wavelength of the undulation pattern when the jet is absorbed.
Besides furthering knowledge in fluid dynamics, this study
presentsamethodforcontrollingthetrajectoriesofliquidjetsafter
theyhavebeenreleased,anengineering problemwhichcurrently
hasnofeasiblesolutions.Thisthereforepresentsnewpossibilities
in areas including inkjet systems, biological encapsulation, and
fiberspinning.
POSTER: HS-02
Sing Teng Chua
VictoriaJuniorCollege,Singapore
chua.sing.teng.2013@vjc.sg
EnergyandEnvironmentalPhysics
Investigation on Metal and Metal Oxides Thin Film as Potential
Low Emission Glass Coating for Window Application
Multilayer coating structures that sandwiched a copper (Cu) thin
film between metal oxides, namely aluminium oxide (Al2O3) and
titanium dioxide (TiO2) were designed and fabricated
experimentally as low-emission (low-e) glass coating that saves
energy for green building window applications. The objective of
this research is to optimise the optical performance of
Al2O3/Cu/Al2O3 and TiO2/Cu/TiO2 as low-e structure. Low-e
glass coating exhibits high visible light (VIS) transmittance while
absorbingultraviolet(UV)andreflectinginfrared(IR)radiation.The
main highlight is the utilisation of Cu, a low-cost metal, in
replacement of silver which is applied commonly in the
commercially available low-e glass. The optimisation of the
multilayerstructureswasperformedusingIMDsoftwaresimulation
andexperimentalmethods.Themultilayercoatingsweresputtered
on the plain glass substrates, after which the thickness of the
structures was measured using surface profilometer. The optical
spectra, namely transmittance and reflectance exhibited by the
multilayer structures were studied using UV-VIS-NIR
spectrophotoscopy.Finally, X-ray Diffraction wasconducted upon
the as-depositedandthermallyannealedsamplesofTiO2/Cu/TiO2
forstructural analysis.The experimental resultsshowed that both
structures exhibited considerably high IR reflectance and
comparatively high VIS transmittance. TiO2/Cu/TiO2 presented
higher VIS and lower UV transmittance but slightly lower IR
reflectance as compared to Al2O3/Cu/Al2O3. This study also
showed that rapid thermal annealing has improved the optical
performance of TiO2/Cu/TiO2 significantly. In conclusion, in this
study, Cu has exhibited a promising potential for low-e glass
coating applications.
104 | The 8th OCPA International Conference on Physics Education and Frontier Physics
POSTER: HS-03
POSTER: HS-05
Lu Wenyu, Gao Yan, Gong Yan*
HwaChongInstitution,Singapore
NanyangTechnologicalUniversity,Singapore
jxgy1994923@163.com
Kai-Yen Jee
RafflesInstitution,Singapore
jeeky1996@yahoo.com.sg
QuantumInformation
Investigating the Self-healing Pattern of Airy Beam with
Perturbation of Different Materials
Scientists have created a special beam which is able to bend in
the air and is diffraction-free. It is named Airy Beam. The Airy
waveform was described theoretically nearly 30 years ago as a
surprisingsolutiontothequantumequationforafreeparticle.The
beam is asymmetric, with one bright region at the center and a
series of progressively dimmer patches onthe side of thecentral
spot. But rather than propagating in a straight line, the entire
pattern of bright and dark patches curves toward one side (selfbend). One of its most remarkable properties is its very ability to
self-reconstruct after being perturbed during propagation in
inhomogeneous media. Our project investigate the selfreconstruction/self-healingpropertyofAiryBeam.
In our project, we first create an airy beam using digital micro
mirror device (DMD). After that we make observation of the selfhealing pattern of airy beam when thin non-transparent, semitransparent and transparent obstacles with various color are
placed on the propagation routine of airy beam and investigate
how the pattern is affected by the material and color of the
obstacles.
After quantifying the data we got, we found that themain lobe of
airybeam,whereenergyconcentrates,isnotaffectedbeforeand
after self-reconstruction regardless of the nature of obstacles.
Hence we suggestthat the airy beam has a strong ability ofselfhealing.Withthisability,weproposetwoapplications:microscopic
Imagingandinformationtransportation.
PhysicsEducation
Investigation on the Dynamics and Apparent Interactions of
Massive Balls Rolling on a Stretched Horizontal Membrane as
a Model to Illustrate Gravitation
A gravity well model, in particular a stretched horizontal
membrane, is often used to illustrate gravitation. Massive balls
placed on it cause a depression due to their weight, thereby
causingnearbyballstorolltowardstheminamannerofattraction
similar to gravity. We aim to investigate whether this analogy to
gravityisanaccurateone,andthiswasdoneintwodifferentways.
We first compared the potential of gravity and the potential
representative of the stretched membrane. We found that the
potential(ie.Shape)ofthemembranetakesonalogarithmicform
and most accurately models gravity in a 2 dimensional universe,
rather than normal 3 dimensional gravity. We were also able to
obtainanexpressionoftheeffectivegravitationalconstantforthe
membrane. Next we compared the dynamics and motion of balls
on the membrane. We found that the motion of balls on the
membrane is greatly affected by rolling friction, the vertical
component of the ball‟s motion, the finite size and weight of the
membrane. Thus, we concluded that the model of a stretched
horizontal membrane illustrates very well a 2 dimensional
gravitational potential, but not when it comes to illustrating the
motionofmasses.
POSTER: HS-06
semiconductor solar cells. It was found that solar cells show an
open-circuit voltage of about 420 mV and short-circuit current of
~5mA/cm2.Otherfactorshavealsobeeninvestigated.
POSTER: HS-08
Yong-Hui Lim
RafflesInstitution,Singapore
yongpig1@yahoo.com.sg
Interdisciplinary Sciences
On the Rebound, Subsequent Motion and Fluid Dynamics of a
Small Fluid-filled Sphere Undergoing a Vertical Impact
Inrecentyears,theusageofdynamicliquiddampershasreceived
much attention. Dampers designed to reduce extreme lateral
motion involve using energy losses from the sloshing motion of
waterincontainers.However,theusageofliquidsasdampersfor
vertical impacts is a more complex phenomenon and less
investigationhasbeenputtoit.Thisisduetotheinvolvementofa
complexliquidjetformationprocess.Whileheavy,largefluid-filled
spheres were studied in previous literature, we consider the
rebound and motion of small, light fluid-filled spheres as they
exhibit more interesting and useful properties. Surface tension
deformsthewatersurfaceunderthezero-gravityreferenceframe,
resultingincavityformation.Uponthefirstbounce,ajetisformed.
A temporary velocity drop is observed after impact due to the jet
formationandsubsequentjetimpactwiththesphere'stopsurface.
Throughtheoreticalcalculationsandnumericalsimulation,weuse
the pressure impulse model to qualitatively predict water
movement immediately after impact to explain jet formation. The
variation of the temporary velocity drop and restitution coefficient
overfluidfillfractionisthenstudiedexperimentally.It isfoundthat
the velocity drop is optimized at a fill fraction of 0.33 with a
minimum velocity ratio of 0.18, while the restitution coefficient is
optimizedatfillfractionsintherangeof0.4to0.6witharestitution
coefficient of approximately 0.5. These values show that small
fluid-filled spheres are effective in acting as vertical damping
devicestoreducebouncingmotion.
POSTER: HS-04
Harman Johll, Karthik Panicker*, Nicole Christie Tan, Hway
Chuan Kang, Eng Soon Tok
1)NationalJuniorCollege,Singapore
2)NationalUniversityofSingapore,Singapore
karthik3004@gmail.com
Xinyi He*, Yihan Zhang
HwaChongInstitution,Singapore
hexinyi51@126.com
Condensed Matter and Materials Sciences
Adsorption of Hydrogen at Stone-Wales Defect Sites in
Silicene
POSTER: HS-09
PhotonicsandPhotovoltaics
An Investigation into the Relationship between the Nozzle
Geometrics and Jet-mixing Behavior
Using density functional theory, we show that the adsorption of
atomic hydrogen on silicene opens a spin polarized band gap in
the electronic density of states. This spin polarized state is no
longer observed with the presence of a rotated Si-Si bond (a
Stone-Walesdefect)adjacenttotheHatom.AdsorptionofHatom
and2Honboth,pristinesiliceneandStone-Walesdefectsilicene
is thermodynamically favourable with the chemisorption of the
latter being more favourable. We discuss these findings and its
implication on hydrogen storage and detection of Stone-Wales
defectsinsilicene.
QuantumInformationScienceandMathematicalPhysics
Investigating the Self-healing Pattern of Airy Beam Over
Different Materials
Our project investigates into the relationship between the nozzle
geometrics and the jet-mixing behaviour. This has important
application inthe infrared reduction technology applied on stealth
fighters. The ideal nozzle design should achieve an optimum
mixingbetweenthecoldambientairandthehotexhaustproduced
bythefighters.Circular,non-inclinednozzlesarecommonlyused,
yet they can be significantly improved. So far, studies on nozzle
modificationfocusoneitherthebasicgeometricsofthenozzles,or
the inclination of the nozzle lip on the basis of circular nozzle.
Therefore, our project aims to investigate improvements in both
characteristics,whichhaveseldombeenstudiedtogetherbefore.
We investigated three rectangular nozzles that have different
inclinations at 0, 30 and 60 degrees respectively. A green laser
with a concave lens fixed in front is used to shine the smoke
stream generated by a smoke generator. In the process of
improving the set-up, we used 3D printer to print nozzles with
different inclined angles, and placed a cylindrical pipe with filters
5.0cmawaythefanstogetadiluteandsteadysmokesupply.
By using Matlab image processing as well as frame-by-frame
analysis,wefoundthatthejetspreadofinclinednozzlesismuch
larger than that of the non-inclined one, duetomore entrainment
ofambientairintothejetthateffectivelyincreasesthecontactarea
between the jet and air. Therefore it is concluded that inclined
rectangular nozzles can effectively improve the mixing
characteristicsoftheexhaustjet.
POSTER: HS-07
Wan-Qi Kee
RafflesInstitution,Singapore
keewanqi@gmail.com
PhotonicsandPhotovoltaics
Fabrication and Characterisation Of α-FeSi2/Si Schottky
Diode Solar Cells
This project aimed to contribute basic information of photovoltaic
propertiesofmetal-semiconductor Schottky solar cells by taking αFeSi2/Si Schottky diode as a model system. This was achieved
through depositing a layer of ~35mm metallic FeSi2 on an n-Si
substrate. The samples were then subjected to rapid thermalannealing(RTA)attemperaturesof700°Cfor60s.Finally,indiumtin oxide(ITO)wasdepositedatroomtemperatureonFeSi2asa
top electrode and a thin film of Al/Ti is sputter deposited on the
backsideofn-SitoachievealowresistanceOhmiccontact.The
photovoltaic properties of the materials were measured under
standard AM 1.5 illumination. The MDC CV system (Advanced
Computerised Semiconductor Measurement) was employed to
conduct the current-voltage tests on the prepared metal-
Wenyu Lu*, Yan Gong, Yan Gao
HwaChongInstitution,Singapore
ranger0119@gmail.com
Inourproject,wewillfirstcreateanairybeamusingdigitalmicro
mirror device (DMD).After that we make observation of the selfhealing pattern of airy beam when thin non-transparent, semitransparent and transparent obstacles with various colour and
materialsareplacedonthepropagationroutineofairybeamand
investigate how the pattern is affected bythematerial andcolour
oftheobstacles.
Wefoundtherateofrecoveryofthemainlobeofairybeam,where
energy concentrates, is not affected before and after selfreconstructionregardlessofthenatureofobstacles.Also,analysis
shows that the extent of recovery for allthe groups is veryclose.
Hence we suggestthat the airy beam has a strong ability ofselfhealing which has strong risilience over the obstacle. With this
ability,weproposetwoapplications:informationtransportation and
lasercutting.
POSTER: HS-10
Milla Samuel*, Koo Ruey Yi, Harman Johll, Kang Hway Chuan,
Tok Eng Soon
1)NationalJuniorCollege,Singapore
2)NationalUniversityofSingapore,Singapore
millasml@live.com.sg
Condensed Matter and Materials Sciences
DFT Study on Distribution of Sn in Ge(100) Surface
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 105
GeSn crystals have attracted much research attention given their
potentialasdirectbandgapsemiconductorsandhenceapplication
invariousoptoelectronicindustries.Inthiswork,densityfunctional
theory calculations were carried out to investigate the stability of
Snatom(s)atvariouspositionsattheGe(100)2x2surface.Both
clean and hydrogen passivated surfaces were investigated.
Comparisons were drawn to the congruent SiGe surface. Our
calculations show that Sn atoms are most stable at the surface
layer,viz.inthebuckleduppositionofasurfacedimer.Instability
increasesastheSngoesdeeperintothebulkofthesystem.Both
these properties resemble the SiGe system. Surface
hydrogenationresultsinSnbeingmoststableinthe3rdlayer(e.g.
layer 1 is the surface layer) for the 2.5% Sn System. This
discriminates the GeSn system from SiGe systems, in which
surface hydrogenation causes the 2nd layer of the system to be
most energeticallyfeasible.Inallcasestheeffectofhydrogenation
istomakethesurfacedimersymmetric.
POSTER: HS-11
Muhammad Arifin Dobson
SMANegeri3Bandung,Indonesia
arifin96@gmail.com
EnergyandEnvironmentalPhysics
EcoSol SunHarvester: Cheap, Energy Efficient, Polycarbonate
Solar Thermal Collector
SolarThermalCollectors(STC)competewithfossilenergy,sofar
theyrepresentonlyasmallpercentageofgeneratedpowerdueto
cost and high embedded energy. I have made an STC (EcoSol
SunHarvester) that is inexpensive, can be mass produced, and
energyefficientbyusingpolycarbonate,inspiredbysuncanopies.
Why Polycarbonate? Its properties are suitable for water heating;
its unique thin design makes it possible to heat water very
effectively.Furthermoreithasmuchlowerembeddedenergythan
copper or stainless STC, making it much more energy efficient.
Lastbutnotleastpolycarbonateisrecyclable.
As the income in energy for STC is proportional to their area,
rather than using glass with an aluminium frame, it is better to
increasethetotalareaforthesamecost.Atmanytimesoftheday
a matt black surface absorbs more heat than a glazed collector
which reflects the sun‟s energy at low angles of incident.
Another innovation of my project is a modified passive water
heating system. Pumped and thermosyphon systems need cold
watertoenterthehottankinordertopushhotwaterout.Withthis
system only hot water enters the tank so in the morning it is still
hot.Thissystemisparticularlyimportantwhenproducingpower.
EcoSol'sefficiencyreaches55-65%onsunnydays,andpaysback
itsembeddedenergyinonly60days(conventionalSTCupto2.46
years)! EcoSol has many applications; dryers, desalination, pool
heating, industrial pre-heating even power generation that we
estimate will be cheaper to build than conventional solar power
plants(PVandThermalSystem)usingpentanewithagasturbine.
POSTER: HS-12
Sijia Pan*, Qinxin Wu
HwaChongInstitution,Singapore
pansijiawx@163.com
Accelerator,Astrophysics,Cosmology,NuclearandParticle
Physics
What's Next? Jumping From 39km High!
OnOct14th,FelixBaumgartner,anAustrianBASEjumper,made
hisrecordjumpfromaheightof38,969.4metersabovesealevel.
Hereachedmaximumverticalspeed(withoutdrogue)of377.1m/s
which is around 1.25 times ofspeed ofsound. In this project, we
aimed to investigated
• Physics behind his jump (Gravitational acceleration, atmospheric
temperature, and pressure at each level of height, air resistance,
velocity,speedofandeffectofhighaltitudeonhumanbody)
• Use this case study to model a jumpfrom50kmhigh.
106 | The 8th OCPA International Conference on Physics Education and Frontier Physics
POSTER: HS-13
Jo-Mei Po
RafflesInstitution,Singapore
always99laugh@gmail.com
Condensed Matter and Material Sciences
Investigating the Effect of Coating ZnO2 Nanoparticles on
Polypropylene (PP) Battery Separator for Lithium-ion
Batteries
This research looks at the characterization of ZnO2 nanoparticle
coating on PP separator, aiming to investigate the effects of
coatinglayeronessentialcharacteristicsofLIBsuchaschemical
stabilitycharacterizedbythickness,ionicconductivitycalculatedby
MacMullinnumber,wettabilityshownbycontactangleandthermal
stability demonstrated by thermal shrinkage. The novelty of this
researchliesinthefactthatZrO2nanoparticleispreparedusinga
commerciallyavailablesol-gel andhydrophobicityofthePPfilmis
overcome, which has been proven to be problem in numerous
applications of thePP film. Good adhesion of ZrO2 nanoparticles
can be observed and the ZrO2 coating also makes the film
hydrophilic. Thermal stability of ZrO2 coated PP film has also
showngreatimprovementascomparedtoanuncoatedsample.
POSTER: HS-14
Fan Bowen, Joel Tan*
HwaChongInstitution,Singapore
joeltan96@gmail.com
PhotonicsandPhotovoltaics
External Cavity Diode Laser
Our project aims to construct an external cavity diode laser with
low line width and to align the system, where a Fabry-Perot
Interferometerformstheresonantcavityforthelaserandthelaser
is a grating-stabilisedexternalcavitydiodelaser.
POSTER: HS-15
Lin Xiao Wen, Chelsea Chia Jia Hwa, Tan Hwee Ling Sharon*,
Harman Johll, Kang Hway Chuan, Tok Eng Soon
1)NationalJuniorCollege,Singapore
2)NationalUniversityofSingapore,Singapore
sharontan1998@yahoo.com.sg
Condensed Matter and Materials Sciences
DFT study of Sn Distribution in Partially Hydrogenated Ge
(100) surfaces
GeSnalloyshaveattractedmuchattentiongiventheirpotentialto
emit mid-IR light important for communications and remote
sensing.Mostcritically,GeSnistoutedtobecomedirectbandgap
semiconductors at a Sn fraction between 6 to 11 atomic percent
and is useful for future electronic and optoelectronic devices.
(Kolodzey et al., 2011) (Tonkikh et al., 2013) In this work, we
carried out density functional theory calculations using the PBE
formalism for the exchange correlation and the PAW for
pseudization to investigate the energetics, electronic and band
structuresoftheGeSn(100)surfacewithSnpositionedinvarious
configurations, and with hydrogen adsorbed at different positions
at the surface.
Sn was found to be the most stable in the 25% hydrogen
monolayercoveragewhenhydrogenisbondedtoeithertheatom
at position a‟ or position a. More importantly, the atom bonded to
hydrogen would always shift in the opposite direction of its
bucklingandsimilartoSiGe(100)surface,therewouldbeapartial
transfer of electrons from the buckled-down to buckled-up atom.
(Liu & Hoffmann, 1995) It was also found that Sn would be the
most stable in all positions except position b‟ in the 50% hydrogen
monolayer Ge coverage for hydrogens bonded to atoms in
positions a‟ and a, whereas Sn in position b‟ would be stable with
hydrogen in positions a‟ and b. Inallcases,
1.SnisalwaysfoundtobeonornearthetopsurfaceofGe(100)
surface.
2.Snwillnotbebondedtoahydrogenatom.
3. Sn which has lost electron density would be pushed to a
buckled-downpositioninthedimer.
our methods are novel, and there is a great potential for
development.
POSTER: HS-18
POSTER: HS-16
Shilin Wang
HwaChongInstitution,Singapore
gigabyte.w@gmail.com
QuantumInformationScienceandMathematicalPhysics
Raman Spectroscopy of Carbon Nanotubes
Carbon nanotubes (CNTs) are well known for having exceptional
physical properties. Their unique electrical properties and high
mechanical strength have generated significant interest in many
fields, and CNTs have already found potential applications in
several industries. However, there is currently no established
model for CNT growth, and several questions for the growth
mechanism of CNTs remain unanswered. Post-synthesis
characterisation of CNTs is therefore crucial for identification and
isolation of carbon nanotubes with the structures and properties
desired for practical use. Raman spectroscopy is an extremely
powerfultoolusedtocharacteriseSWNTsduetothenatureofthe
C-C bonds present in CNTs. However, speed and resolution are
always the two extremes in any measurement. Improvement in
oneaspectisalmostalwaysachievedattheexpenseoftheother.
High resolution Raman spectral images in a large area may
contain up to millions of Raman spectra depending on the
parametersset,andRamanspectralimagingonsuchscalescould
takeuptodays.Thisstudyhencepresentsanovelmethodforfast
Ramanspectralimagingofcarbonnanotubes.SWNTsweregrown
on Si/SiO2 substrate marked with trenches using the method of
CVD.Scanningelectronmicroscopywasusedtoobtainanimage
of the substrate surface, and the trenches allow for fast and
efficient location of SWNTs on the substrate surface. Using
resonantRamanscattering,theCNTswereimagedwithinminutes.
Thespectralimageacquiredhasaspatialresolutionofsub-micro,
andeachimagingspotcontainseveryfingerprintoftheCNT.
POSTER: HS-17
Tong Hui Kang, Peh Yu Xiang
AndersonJuniorCollege,Singapore
tonghuikang@outlook.com
ComputationalandMathematicalPhysics
Generalised Euler Factorisation Method
RSA is now the most popular public-key cryptosystem with wide
applicationsinmoderncryptography.ThesecurityofRSAdepends
onthedifficultyoffactoringlargesemiprimes,numberswhichare
theproductsoftwoprimes.
Given the two representations of the semiprime as a sum of two
squares, the Euler‟s Factorisation Method obtains the factors.
However,thismethodisneglectedbecauseitisdifficulttofindthe
two representations. Hence we generalise the Euler Factorisation
Method to use two representations of sum of four squares. Our
approachestothemethodarebasedonthetheoryofquaternions,
whichisanumbersystemthatextendsthecomplexnumbers.
Assumingthatwemanagetogeneratequaternionswithacommon
integral quaternion divisor PQ and PQ‟, with a norm pq the
semiprime, we can implement the Euclidean algorithm to obtain
the prime factors. However, it may be difficult to even find such
pairofquaternionsinthe firstplace.
ThesearchforthepairofquaternionsPQandQPmaybeeasier
because they have the same real part. The prime factor can be
obtained from the system of 7 bilinear equations of 8 unknowns.
Toourbesteffort,weareabletoexpresstwoofthe components
of the quaternion factor P in terms of the other two, and then a
bruteforcesearchisrequired.
We are pleased that we have managed to apply some theory of
quaternions on the integer factorisation problem.We believe that
Francis Wang, David Kum, AbdurRahmaan Al-Mubaarak
NUSHighSchoolofMath&Science,Singapore
nhstkc@nus.edu.sg
AcceleratorPhysics,Astrophysics,Cosmology,ParticlePhysics
andNuclearPhysics
A Statistical Analysis of Dark Matter through Galactic
Rotation Curves
The existence of Dark Matter, non-baryonic weakly interacting
particles invisible to electromagnetic radiation has been
establishedbeyonddoubtoverthepastdecades,theidentity and
characteristics of which are as of yet a large unknown. It is
believed that every galaxy possesses what is known as a Dark
Matter halo, an approximately spherically symmetric aggregation
ofDarkMatterthatconstitutesthevastmajorityofthemass ofthe
galaxy.Intheliterature,thereexistseveraldifferingdensitymodels
to predict the distribution of galactic Dark Matter, with a limited
consensus as to which models best fit the available data. In our
project, we have studied three of the more popular models –
namelythePseudo-IsothermalSphereprofile,theNavarro-FrenkWhite (NFW) profile and the Burkert profile. By utilizing the
rotationalvelocityofstarsandgasasaprobeofthegravitational
influence of Dark Matter on astatisticallysignificant population of
galaxies, we have established that among the three models, the
Burkert profile is least capable of explaining the observed data.
ThePseudo-IsothermalSphereandNFWmodelsproducelargely
similarresults,withtheformerbeingslightlyfavoured.Finally,we
haveinferredrelationshipsbetweenthevariousmodelparameters
and the visible characteristics of the galaxies, which serves to
shedlightonthepropertiesofgalacticDarkMatter.
POSTER: HS-19
Kee Sejie, Edmund Kee*, Yap, ZiQi, Dang Thi Mai, Vy
1)AndersonJuniorCollege,Singapore
2)NgeeAnnPolytechnic,Singapore
edmund-kee@hotmail.com
Biophysics,ChemicalPhysicsandSoftCondensedMatter
2-in-1 Recyclable use of Spent Bentonite to Treat Volatile
Organic Compounds in Industrial Wastewater
In this study, the feasibility of the 2-in-1 recyclable use of spent
Bentonitetotreatvolatileorganiccompounds(VOCs)inindustrial
wastewaterthroughanovel2-stepsurfaceadsorptionmechanism
is validated. Due to isomorphous inter-layer substitution of ions,
raw Bentonite‟s surface is hydrophillic. Hence, raw Bentonite is an
ineffectivesorbentforVOCsdespitehavinghighsurfacearea.The
influence of Bentonite‟s layered expansion from wetting on
adsorptionperformancewasalso explored.
SpentBentonitewasgeneratedbybatchadsorptionwithsimulated
waste water using TOP detergent while it‟s dried counterpart is
subjected to further oven-drying and grinding processes.
Adsorptionperformancewasdeterminedthroughtolueneremoval
by flocculation - which is measured by GC-MS and analysed via
Langmuir&Frendulichadsorptionisothermplots.
Results indicate that wetted Bentonite has better adsorption
performancethandriedandgrindedBentonite.SpentBentoniteis
also proven to have a higher affinity to adsorb VOCs than raw
Bentonite. Spent wetted Bentonite‟s affinity to adsorb toluene is
demonstrated by R2 > 0.9 fits to both Langmuir & Frendulich
models. Frendulich equation parameter‟s n >1 value meant that
the adsorbate on the Bentonite can be removed by a similar
physical reaction and thus, recyclable. 0<R<1 equilibrum
parameter from the Langmuir isotherm proved that adsorption of
tolueneontospentwettedBentoniteisfavourable.
Hence,ourinvestigationconcludedthatourproposed mechanism
isvalidandthatthewastefromoneindustrycanbeconvertedinto
resource for another by using cheap and abundant Bentonite for
flocculation.
The 8th OCPA International Conference on Physics Education and Frontier Physics
| 107