Indian Journal of Pure and Applied Physics
___________________________________________________________________________________
VOLUME 39
NUMBER 10
OCTOBER 2001
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CONTENTS
General
Strong BBP couplings for the charmed baryons
R C Verma* & M P Khanna
615
Atomic and Molecular Physics
Normal coordinate analysis of 5-fluoro, 5-chloro and 5-bromo-cytosines
V Krishnakumar* & V Balachandran
623
Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics
Optimal efficiency of an irreversible heat engine with thermal reservoir of finite
heat capacitance using method of Lagraing multiplier
S C Kaushik* & P Kumar
628
Computer controlled femtosecond optical delay line for ultrafast optics and spectroscopy
R Justin Rajesh, T S Natarajan & Prem B Bisht*
636
Performance analysis of a shallow solar pond water-heater
Ajai Shankar Prasad
640
Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Optical absorption edge and Urbach tails for Tl0.999 Ga Pr0.001 Se2 Tl0.995 Ga Pr0.005 Se2 and Tl Ga Se2
B Gürbulak
Transport properties of SnTexSe1-x thin films
H A Zayed, L I Soliman*, B S Farag & F M Shehata
Electrical properties of chalcogenide glassy alloys of the system Se100-x In2
S Abou El-Hassan
Electric field dependent microwave loss in BaTiO3 and KTaO3
D S Lingwal*, U C Naithani & B S Semwal
Field dependent dielctric behaviour of BaTiO 3, SrTiO3 and K TaO3 perovskites
D S Lingwal*, U C Naithani, Ashok Kumar & B S Semwal
Interdisciplinary Physics and Related Areas of Science and Technology
Radon induced radiological impact of coal, flyash and cement samples
K Kant*, R P Chauhan, G S Sharma & S K Chakravarti
Application of magnetic fluids in medicine and biotechnology
C N Ramchand* Priyadarshini Pandey, Peter Kopcansky & R V Mehta
____________
*The corresponding author has been indicated by (*) mark in case of papers with more than one author
647
654
661
668
673
679
683
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp.615-622
Strong BBP couplings for the charmed baryons
R C Verma & M P Khanna*
Department of Physics, Punjabi University, Patiala 147 002
*Centre for Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh 160 014
Received 21 January, 2000; revised 20 March 2001; accepted 4 April 2001
According to the Coleman-Glashow null theorem if all the symmetry breaking effects belong to the same regular
representation (octet in the case of SU(3) and 15 in the case of SU(4)) and are generated in a tadpole type mechanism, the
strangeness changing (charm changing) weak transitions generated through the S 6 (S9) tadpole must vanish. Exploiting this
null result, relations between the BBP coupling constants are obtained, which leads to the coupling constants in terms of
two parameters and baryon masses. Fixing these two parameters ( g NN  and g   ) from experiments, the remaining
coupling constants are estimated.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 623-627
Normal coordinate analysis of 5-fluoro, 5-chloro and
5-bromo-cytosines
V Krishnakumar & V Balachandran*
Department of Physics, Nehru Memorial College, Puthanampatti 621 007
Received 27 December 2000; revised 9 July 2001; accepted 23 July 2001
Normal coordinate calculations of 5-fluoro, 5-chloro and 5-bromo-cytosines were carried out using
Wilson’s F-G matrix mechanism on the basis of General Valence Force Field for both in-plane and out-ofplane vibrations. The potential energy constants obtained in this study were refined using numerical methods.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 628-635
Optimal efficiency of an irreversible heat engine with thermal reservoir of
finite heat capacitance using method of Lagrangian multiplier
S C Kaushik & P Kumar
Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-110016
Received 4 December 2000; accepted 9 April 2001
The finite time thermodynamic optimization of an irreversible heat engine having thermal reservoirs of
finite heat capacitance has been presented. A general expression for the optimum efficiency of heat engine is
derived at maximum work output and given heat input flow rate condition. External irreversibility is due to
finite temperature difference between system working fluid and thermal reservoirs (source/sink) while internal
irreversibility is due to non-isentropic expansion and compression within the system which is represented by an
irreversibility parameter indicating the deviation from endoreversible case. It is found that the effect of internal
irreversibility is more pronounced than the external irreversibility associated with the heat engine. The effect of
various operating parameters on the efficiency of the heat engine is studied and numerical results are presented
in the end.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 636-639
Computer controlled femtosecond optical delay line for ultrafast optics and
spectroscopy
R Justin Rajesh, T S Natarajan & Prem B Bisht
Department of Physics, Indian Institute of Technology Madras, Chennai - 600 036
Received 1 December 2000; revised 18 January 2001; accepted 23 July 2001
A computer controlled optical delay line for experiments in ultrafast laser optics and spectroscopy has been
fabricated. Spatial resolution of 0.5 m and an optical resolution of 16 fs have been obtained from the set up. An
ultrafast decay of 50 ps for the relaxation of an organic dye has been recorded using this set up as an example.
Fabrication details of this economical and indigenous PC-controlled optical delay line along with the software
requirement are presented here.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 640-646
Performance analysis of a shallow solar pond water-heater
Ajai Shankar Prasad
Department of Physics, R.B. Jalan Bela College, Bela, Darbhanga 846 005
Received 18 July 2000; revised 19 February 2001; accepted 16 April 2001
A simple algebraic equation for water temperature is expressed in terms of time and space coordinate. This
is useful for determining the water temperature at any instant of time of any position, along the length of the
collector. The effects of collector-length, water-depth and the flow-velocity have been analysed. The
performance of the system is also addressed under both the evaporation and without-evaporation conditions.
For appreciation of analytical results, numerical calculations were made employing meteorological parameters
for a typical winter day in Delhi.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 647-653
Optical absorption edge and Urbach tails for Tl0.999GaPr0.001Se2,
Tl0.995GaPr0.005Se2 and TlGaSe2
B Gürbulak
Atatürk University, Faculty of Sciences, Department of Physics, 25240 Erzurum, Türkiye
Received 27 November 2000; revised 19 June 2001; accepted 6 July 2001
TlGaSe2, Tl0.999GaPr0.001Se2 and Tl0.995GaPr0.005Se2 single crystals were grown by the Stockbarger method. The
absorption measurements were carried out in these samples in temperature range 10-320 K with a step of 10 K. The
phonon energies calculated in TlGaSe2, Tl0.999GaPr0.001Se2 and Tl0.995GaPr0.005Se2 are 60.05, 55.05 and 130.05 meV
respectively. The first defect levels (n=1) have been found as 2.259, 2.235, 2.200 and 2.149 eV for Tl 0.999GaPr0.001Se2
and 2.254, 2.225, 2.189 and 2.149 eV for Tl 0.995GaPr0.005Se2 at 10, 100, 200 and 300 K. At 300 K direct band gap of
TlGaSe2 is 2.156 eV, and indirect band gap is 2.075 eV. There are abrupt changes in the Urbach energy peaks for
Tl0.999GaPr0.001Se2 at 100 and 200 K, and Tl0.995GaPr0.005Se2 at 200 and 260 K. There is an abrupt change in the 0
values for Tl0.999GaPr0.001Se2 and Tl0.995GaPr0.005Se2 in the temperature range 140-180 K and 220-260 K. These
temperatures obtained from the changing of Urbach energy and 0 values may be phase transition temperatures.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 654-660
Transport properties of SnTexSe1-x thin films
H A Zayed, L I Soliman*, B S Farag* & F M Shehata
Received 23 January 2001; revised 20 June 2001; accepted 28 June 2001
The ternary semiconductors SnTexSe1- x (where 0 x 1), were prepared by fusion method. The SnTexSe1-x thin films
were prepared by thermal evaporation under vacuum of about 10 -5 Torr .The structure and the composition analysis of
SnTexSe1-x in powder and this films form were investigated by X-ray diffraction and microprobe analysis technique
respectively. It was found that the electrical conductivity  increases, while the activation energy decreased with increasing
composition (x). The thermoelectric power and Hall voltage measurements indicated that the SnTexSe1-x thin films were Ptype conduction. The SnTexSe1-x thin films were non-degenerate semiconductor for all values of x from zero to 0.8, while
for SnTe (x = 1) the films were degenerate and had a metallic behaviour. Moreover the carrier density P was changed from
~ 1017 to 1021 cm-3 as x changed from zero to one. It was found that the mobility of SnTe xSe1-x thin films increased as x
increased, which indicated the presence of two types of scattering mechanisms, namely ionized impurity scattering as well
as grain boundary potential barrier scattering. The effective mass m* of SnTexSe1-x thin films were found to increase with
composition x.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 661-667
Electrical properties of some chalcogenide glassy alloys
of the system Se100-X InX
S Abou EL-Hassan
Faculty of science, Physics department, Benha University, Benha, Egypt
Received 18 August 2000; accepted 27 July 2001
DC electrical properties of the system Se100-x InX (where x =5, 10, 15 and 20 at. %) have been carried out. I–V
characteristics of this system are discussed in terms of Pool-Frenkel and Schottkey effect. The jump distance (d), charge
carrier concentration (n) and the trap depth () have been deduced for the system. According to Arrhenius Eq. of
conductivity, the activation energy of conduction w1 and w2 for the two arms of conductivity have been found in the
range from 0.18 to 1.2 eV. Both of mobility () and diffusion coefficients are calculated for different compositions at
different ambient temperatures. The activation energy due to mobility (U) and diffusion (Q) mechanisms have been
deduced and their values were ranged from 0.02 to 0.4 eV. The behaviour of W1 , U and Q has the same trend with
composition, which indicate that the conduction mechanism is controlled by one type of process. Meyer–Neldel rule has
been applied on our results and a confirmation of this rule has been found.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 668-672
Electric field dependent microwave loss in BaTiO3 and KTaO3
D S Lingwal, U C Naithani & B S Semwal
Department of Physics, HNB Garhwal University Campus, Pauri (Garhwal), Uttaranchal 246 001
Received 6 February 2001; revised 25 May 2001; accepted 6 August 2001
The electric field dependent microwave loss of anharmonic pure BaTiO 3 and KTaO3 ferroelectric crystals has been
calculated in its paraelectric phase from the Silverman-Joseph Hamiltonian augmented with fourth order phonon coordinates using double time Green’s functions. The loss tangent consists of a contribution, which is quardratic in applied
biasing and is a field independent contribution. The variation of tan  with applied field is noticeable in the vicinity of Curie
temperature. In the higher temperature region, the electric field effect ceases and the increase in loss arises mainly due to
higher order anharmonic terms. In both cases (BaTiO3 and KTaO3) loss tangent increases with the increasing electric field.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 673-678
Field dependent dielectric behaviour
of BaTiO3 , SrTiO3 and KTaO3 perovskites
D S Lingwal, U C Naithani, Ashok Kumar & B S Semwal
Department of Physics, HNB Garhwal University, Campus Pauri (Garhwal), Uttaranchal 246 001
Received 27 February 2001; revised 6 July 2001; accepted 6 August 2001
The electric field dependence of the complex dielectric constant in anharmonic ferroelectric crystals are calculated in
its paraelectric phase from the Silverman-Joseph Hamiltonian augmented with fourth order phonon co-ordinates using
double time Green’s functions technique. The frequency, temperature and electric field dependent dielectric constant of
BaTiO3, SrTiO3 and KTaO3 crystals have been discussed. Dielectric constant increases with increase of applied field in
BaTiO3, SrTiO3 and KTaO3 cases.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 679-682
Radon induced radiological impact of coal, fly ash and cement
samples
K Kanta, R P Chauhanb, G S Sharmac and S K Chakarvartid
aDepartment
of Physics, GGDSD College, Palwal (Faridabad), Haryana 121 102
bDepartment
of Physics, IGN College, Ladwa (Kurukshetra), Haryana 136 132
cDepartment
dDepartment
of Physics, BSA College, Mathura, (UP) 281 001
of Applied Physics, Regional Engineering College, Kurukshetra 136 119
Received 23 October 2000; revised 9 July 2001; accepted 6 August 2001
Coal and its by-product fly ash are technologically important materials being used for power generation and in the
manufacture of bricks, sheets, cement, land-filling, etc. respectively. Increased interest in measuring radon concentration in
coal, fly ash and cement is due to its health hazards and environmental pollution. As the presence of radon in the
environment (indoor and outdoor), soil, ground water, oil and gas deposits contributes the largest fraction of the natural
radiation dose to populations, tracking its concentration is thus of paramount importance for radiological protection.
Samples of coal and fly ash were collected from different thermal power stations in northern India and cement samples
from National Council for Cement and Building Materials, Ballabgarh (Haryana), India and were analysed for radon
concentration. For the measurement, alpha sensitive LR-115 type II plastic track detectors were used. Based upon the
available data, the annual effective dose and the lifetime fatality risk factors have been calculated. The radon concentration
from coal samples varied from 433  28 Bq m-3 to 2086  28 Bq m-3. The radon concentration from fly ash samples varied
from 748  28 Bq m-3 to 1417  111 Bq m-3 and from 158 Bq m-3 to 1810 Bq m-3 in cement samples, with an average of 624
 169 Bq m-3.
Indian Journal of Pure & Applied Physics
Vol. 39, October 2001, pp. 683-686
Application of magnetic fluids in medicine and biotechnology
C N Ramchand and Priyadarshini Pande
Sun Pharma Advanced Research Centre, Akota Road, Akota, Baroda, India
Peter Kopcansky
Institute of Experimental Physics, Slovakian Academy of Science, Kosice, Slovak Republic
and
R V Mehta,
Department of physics, Bhavnagar University, Bhavnagar, India
Received 15 May 2001; accepted 26 June 2001
Several advancements have been made in the last two decades for targeting drugs to a specific area in the
human body. Liposomes, resealed erythrocyte ghost preparations, antibody mediated drug targeting to specific
cancer cells have become popular means of drug targeting. However all these methods are associated with
several practical problems and involve tedious development stages. In the past few years, this group has been
involved in developing the usage of magnetic particles as suitable carriers for delivering drugs. This method of
drug delivery ensures site-specific action as well as easy to develop and use technology. Clot lytic agents like
streptokinase, urokinase or tissue plasminogen activator are traditionally used for treating thrombosis. One of
the major problems associated with this treatment is its nonspecific and undirected thrombolytic activity. Using
magnetic fluids, as carriers for above enzymes would ensure specificity of action, reduction in amount and time
of action of the drug with no side effects. This line of action could be used in treating peripheral and coronary
occlusive diseases. The process of hysteresis can be utilized to develop heat in magnetic fluids and this can be
used to induce hyperthermia to treat tissues/cells, especially in oncology. This, in addition to delivering
anticancer drugs via magnetic particles could prove to be an excellent line of treatment for cancer
chemotherapy. Phase I clinical trials using reversibly bound anticancer drug epirubicin were done, and it was
found that the ferrofluid could be successfully directed to the tumors in about one-half of the patients. Present
studies have shown that proteins can be bound to magnetic particles without losing their biological properties.
Some of the enzymes immobilized by us have been found to retain almost 90% of their activity. The same
principle could be used to deliver anticancer and thrombolytic drugs, which have been entrapped in protein
microspheres. These can be targeted to tumor cells by an external magnetic field so that it can deliver the drug
slowly and in the required amount at the same time avoiding side effects associated with these drugs. The
applications of magnetic fluids in other fields are also manifold. Magnetic for isolating mRNA are quicker and
more efficient, and they avoid organic solvents and the need for a precipitation step. Magnetic beads linked to
high affinity capture antibodies have been widely accepted as separation techniques of specific target ligands or
particles such as bacteria or leukocytes from complex mixtures, such as bone marrow, blood and other body
fluids. Detection of contaminating microorganisms like staphylococcus sp. In milk using a magnetic based
ELISA (Enzyme Linked Immunosorbent Assay) has been developed. It is also proposed to use this technology
to immobilize polymixin B antibiotic for the treatment of endotoxic shock. The extreme toxicity of this
antibiotic could be avoided using dialysis to remove the magnetically bound antibiotic, from systematic
circulation, after its action. Similarly using magnetically immobilized antifungal agent amphoterecin, for
systemic application, could reduce toxicity of this antifungal agent. Investigating the use of magnetically
immobilized Horseshoe crab protein for combating endotoxic shock could also prove to be an effective line of
treatment. Using magnetic particles as such or erythrocyte ghost preparations of the same could be used as an
opaque medium in angiography and radiography techniques. In addition to this, using magnetically
immobilized microorganisms for wastewater treatment is an extremely cost effective technology.