Hindawi Publishing Corporation Abstract and Applied Analysis Volume 2013, Article ID 869438, 19 pages http://dx.doi.org/10.1155/2013/869438 Research Article Some Explicit Expressions and Interesting Bifurcation Phenomena for Nonlinear Waves in Generalized Zakharov Equations Shaoyong Li1,2 and Rui Liu1 1 2 Department of Mathematics, South China University of Technology, Guangzhou, Guangdong 510640, China College of Mathematics and Information Sciences, Shaoguan University, Shaoguan, Guangdong 512005, China Correspondence should be addressed to Rui Liu; scliurui@scut.edu.cn Received 22 December 2012; Revised 7 February 2013; Accepted 17 February 2013 Academic Editor: Chun-Lei Tang Copyright © 2013 S. Li and R. Liu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Using bifurcation method of dynamical systems, we investigate the nonlinear waves for the generalized Zakharov equations π’π‘π‘ − ππ 2 π’π₯π₯ = π½(|πΈ|2 )π₯π₯ , ππΈπ‘ +πΌπΈπ₯π₯ −πΏ1 π’πΈ+πΏ2 |πΈ|2 πΈ+πΏ3 |πΈ|4 πΈ = 0, where πΌ, π½, πΏ1 , πΏ2 , πΏ3 , and ππ are real parameters, πΈ = πΈ(π₯, π‘) is a complex function, and π’ = π’(π₯, π‘) is a real function. We obtain the following results. (i) Three types of explicit expressions of nonlinear waves are obtained, that is, the fractional expressions, the trigonometric expressions, and the exp-function expressions. (ii) Under different parameter conditions, these expressions represent symmetric and antisymmetric solitary waves, kink and antikink waves, symmetric periodic and periodic-blow-up waves, and 1-blow-up and 2-blow-up waves. We point out that there are two sets of kink waves which are called tall-kink waves and low-kink waves, respectively. (iii) Five kinds of interesting bifurcation phenomena are revealed. The first kind is that the 1-blow-up waves can be bifurcated from the periodic-blow-up and 2-blow-up waves. The second kind is that the 2-blow-up waves can be bifurcated from the periodic-blow-up waves. The third kind is that the symmetric solitary waves can be bifurcated from the symmetric periodic waves. The fourth kind is that the low-kink waves can be bifurcated from four types of nonlinear waves, the symmetric solitary waves, the 1-blow-up waves, the tall-kink waves, and the antisymmetric solitary waves. The fifth kind is that the tall-kink waves can be bifurcated from the symmetric periodic waves. We also show that the exp-function expressions include some results given by pioneers. 1. Introduction Since the exact solutions to nonlinear wave equations help to understand the characteristics of nonlinear equations, seeking exact solutions of nonlinear equations is an important subject. For this purpose, there have been many methods such as the Jacobi elliptic function method [1, 2], F-expansion method [3, 4], and (πΊσΈ /πΊ)-expansion method [5, 6]. Recently, the bifurcation method of dynamical systems [7–9] has been introduced to study the nonlinear partial differential equations. Up to now, the method is widely used in literatures such as [10–16]. In this paper, we consider the generalized Zakharov equations [17], which read as π’π‘π‘ − ππ 2 π’π₯π₯ = π½(|πΈ|2 )π₯π₯ , ππΈπ‘ + πΌπΈπ₯π₯ − πΏ1 π’πΈ + πΏ2 |πΈ|2 πΈ + πΏ3 |πΈ|4 πΈ = 0, (1) where πΌ, π½, πΏ1 , πΏ2 , πΏ3 , and ππ are real parameters. πΈ = πΈ(π₯, π‘) is a complex function which represents the envelop of the electric field, and π’ = π’(π₯, π‘) is a real function which represents the plasma density measured from its equilibrium value. Huang and Zhang [17] used Fan’s direct algebraic method to obtain some exact travelling wave solutions of (1) as follows: ± = π’π0 π½ 2 (π± ) , π2 − ππ 2 π0 ± ± π(πΎπ₯−ππ‘) πΈπ0 = ππ0 π , ± = π’π0 π½ 2 (π± ) , π2 − ππ 2 π0 ± ± π(πΎπ₯−ππ‘) πΈπ0 = ππ0 π , ± = π’π0 π½ 2 (π± ) , π2 − ππ 2 π0 ± ± π(πΎπ₯−ππ‘) πΈπ0 = ππ0 π , 2 Abstract and Applied Analysis π½ 2 (π± ) , π2 − ππ 2 π0 ± = π’π0 ± π’π0 = π2 ± ± π(πΎπ₯−ππ‘) πΈπ0 = ππ0 π , π½ ± 2 (ππ0 ), 2 − ππ ± ± π(πΎπ₯−ππ‘) πΈπ0 = ππ0 π , (2) where πΎ and π€ are two constants and ± ππ0 = ±√ −12π 3π − √9π2 − 48ππ cos (2√−ππ) , (3) ± = ±√ ππ0 2π (−1 + tanh (√ππ)), π (4) ± ππ0 = ±√ 2π (−1 − tanh (√ππ)), π (5) ± = ±√ ππ0 12π −3π + √9π2 − 48ππ cosh (2√ππ) ± = ±√ ππ0 2π (−1 − coth (√ππ)), π π = π₯ − ππ‘, π= πΌπΎ2 − π , πΌ π½πΏ1 πΏ − 2, π= 2 2 πΌ (π − ππ ) πΌ , (6) (7) (8) (9) (10) πΏ3 , πΌ (11) π = 2πΌπΎ. (12) π=− When πΌ = 1, π½ = −1, πΏ1 = −2, πΏ2 = 2π, πΏ3 = 0, and ππ = 1, (1) reduce to the equations π’π‘π‘ − π’π₯π₯ + (|πΈ|2 )π₯π₯ = 0, ππΈπ‘ + πΈπ₯π₯ + 2π’πΈ + 2π|πΈ|2 πΈ = 0. ππΈπ‘ + πΈπ₯π₯ + 2π’πΈ = 0. 2. Main Results In this section, we state our main results. To relate conveniently, let us give some notations which will be used in the latter statement and the derivations. Let ππ (π = 1, 2, . . . , 7) represent the following seven curves: π1 : π = π2 4π (π > 0, π < 0) , (15) π2 : π = 3π2 16π (π > 0, π < 0) , (16) π3 : π = 0 (π > 0, π < 0) , (17) π4 : π = 0 (π > 0, π > 0) , (18) π5 : π = 0 (π < 0, π > 0) , (19) π6 : π = 3π2 16π (π < 0, π > 0) , (20) π7 : π = π2 4π (π < 0, π < 0) . (21) (13) El-Wakil et al. [18] used the extended Jacobi elliptic function expansion method to obtain some Jacobi elliptic function expression solutions of (13). When π = 0, (13) reduce to the equations π’π‘π‘ − π’π₯π₯ + (|πΈ|2 )π₯π₯ = 0, In this paper, we investigate the nonlinear waves and the bifurcation phenomena of (1). Coincidentally, under some transformations, (1) reduce to a planar system (54) which is similar to the planar system obtained by Feng and Li [16]. Many exact explicit parametric representations of solitary waves, kink and antikink waves, and periodic waves were obtained in [16], and their work is very important for the π6 model. In order to find the travelling wave solutions of (1), here we consider (1) by using the bifurcation method mentioned above; firstly, we obtain three types of explicit nonlinear wave solutions, this is, the fractional expressions, the trigonometric expressions, and the exp-function expressions. Secondly, we point out that these expressions represent symmetric and antisymmetric solitary waves, kink and antikink waves, symmetric periodic and periodic-blow-up waves, and 1-blow-up and 2-blow-up waves under different parameter conditions. Thirdly, we reveal five kinds of interesting bifurcation phenomena mentioned in the abstract above. The remainder of this paper is organized as follows. In Section 2, we give some notations and state our main results. In Section 3, we give derivations for our results. A brief conclusion is given in Section 4. (14) By multisymplectic numerical method, Wang [19] proved the preservation of discrete normal conservation law of (14) theoretically and investigated the propagation and collision behaviors of the solitary waves numerically. There are also many other researchers studying (1) or its special case; for more information, one can see [20–24]. Let π΄ π (π = 1, 2, . . . , 12) represent the regions surrounded by the curves ππ (π = 1, 2, . . . , 7) and the coordinate axes (see Figure 1). Let π½ π2 (π) , π2 − ππ 2 (22) πΈ (π₯, π‘) = π (π) ππ(πΎπ₯−ππ‘) , (23) Δ = √π2 − 4ππ, (24) −π + Δ , 2π (25) π’ (π₯, π‘) = π1 = √ Abstract and Applied Analysis 3 π π π1 π΄7 π΄8 π2 π π΄5 π΄4 π5 π΄ 12 π΄6 π΄9 π΄ 11 π΄ 10 π΄3 π3 π π4 π π΄2 π6 π π΄1 π7 (a) π > 0 (b) π < 0 Figure 1: The locations of the regions π΄ π (π = 1, 2, . . . , 12) and curves ππ (π = 1, 2, . . . , 7). π2 = √ −π − Δ , 2π (26) π» (π, π¦) = β, (27) where π»(π, π¦) is the first integral which will be given later and β is the integral constant. In order to search for the solutions of (1) and studing the bifurcation phenomena, we only need to get the solution π(π) according to (22) and (23). For convenience, throughout the following work we only discuss the solution π(π). Now let us state our main results in the following Propositions 1, 2, and 3. 2.1. When the Orbit Γ Is Defined by π»(π,π¦)=π»(0, 0) Proposition 1. (i) For π = 0, (1) have two fractional nonlinear wave solutions π½ 2 πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , π’π± = 2 2 (ππ± ) , (28) π − ππ These solutions have the following properties and wave shapes. ± and ππ± are periodic(1) When (π, π) ∈ π΄ 1 or π΄ 2 , then ππ0 blow-up waves (refer to Figure 2(a) or Figure 3(a)). Specially, in region π΄ 1 when π → 0 − 0, the periodic± become 1-blow-up waves ππ± , and blow-up waves ππ0 for the varying process, see Figure 2, while the periodicblow-up waves ππ± become a trivial wave π = 0. In region π΄ 2 when π → 0−0, the periodic-blow-up waves ππ± become 2-blow-up waves ππ± , and for the varying process, see Figure 3. ± (2) When (π, π) ∈ π΄ 12 , then ππ0 and ππ± are symmetric periodic waves (refer to Figure 5(a)). If π → 0 − 0, ± become symmetric the symmetric periodic waves ππ0 ± solitary waves ππ , and for the varying process, see Figure 4. If π → 3π2 /16π + 0, the symmetric periodic ± and ππ± become two trivial waves π = waves ππ0 ±√−(3π/4π), and for the varying process, see Figure 5. (iii) For π > 0, (1) have four nonlinear wave solutions where 6π ππ± = ±√ 2 2 . 3π π − 4π (29) If (π, π) ∈ π4 , then ππ± are 1-blow-up waves (refer to Figure 2(d)). If (π, π) ∈ π3 , then ππ± are 2-blow-up waves (refer to Figure 3(d)). If (π, π) ∈ π5 , then ππ± are symmetric solitary waves (refer to Figure 4(d)). (ii) For π < 0, (1) have two nonlinear wave solutions π’π± = π2 π½ 2 (ππ± ) , 2 − ππ πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , (30) where ππ± = ±√ −12π 3π + √9π2 − 48ππ cos (2√−ππ) π’π± = . (31) π’π± π½ 2 (π± ) , π2 − ππ 2 π π½ 2 = 2 2 (ππ± ) , π − ππ πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , (32) πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , where ππ± = ±√ 4ππ , π2 π2√ππ + (π 0 /12) π−2√ππ − ππ (33) 4ππ , ππ± = ±√ 2 −2√ππ ππ + (π 0 /12) π2√ππ − ππ π is a nonzero arbitrary real constant and π 0 = 3π2 − 16ππ. Corresponding to π > 0 or π < 0, these solutions have the following properties and wave shapes. 4 Abstract and Applied Analysis π + ππ0 π + ππ0 0 + ππ0 0 π − ππ0 − ππ0 − ππ0 (b) π π + ππ0 + ππ0 0 − ππ0 π − ππ0 (a) + ππ0 + ππ0 + ππ0 0 π π − ππ0 − ππ0 (c) − ππ0 (d) ± Figure 2: (The 1-blow-up waves are bifurcated from the periodic-blow-up waves.) The varying process for the figures of ππ0 when (π, π) ∈ π΄ 1 −1 −2 −3 −4 and π → 0 − 0, where π = 1, π = 4 and (a) π = 0 − 10 , (b) π = 0 − 10 , (c) π = 0 − 10 , and (d) π = 0 − 10 . (1) For the case of π > 0, there are four properties as follows. (1)a When (π, π) ∈ π2 , that is, π > 0, π < 0, and π = 3π2 /16π, then ππ± and ππ± become ± = ±√ ππ1 4π ππ2√ππ −π , (34) ± = ±√ ππ1 4π ππ−2√ππ − π , which represent four low-kink waves (refer to Figure 6(d) or Figure 7(d)). Specially, let π = ± ± ± ± and ππ1 become ππ0 and ππ0 . −π > 0, then ππ1 (1)b If (π, π) belongs to one of π΄ 3 , π΄ 7 , π΄ 8 , and π =ΜΈ √π 0 /12, then ππ± =ΜΈ ππ± , and they represent four symmetric solitary waves (refer to Figure 6(a)). Specially, when (π, π) ∈ π΄ 3 and π → 3π2 /16π − 0, then the four symmetric solitary waves ππ± and ππ± become the four low± ± and ππ1 , and for the varying kink waves ππ1 process, see Figure 6. (1)c If (π, π) belongs to one of π΄ 4 , π΄ 5 , π΄ 6 , π1 , and π =ΜΈ √π 0 /12, then ππ± =ΜΈ ππ± , and they represent four 1-blow-up waves (refer to Figure 7(a)). Specially, when (π, π) ∈ π΄ 4 and π → 3π2 /16π + 0, then the four 1-blow-up waves ππ± and ππ± become ± ± and ππ1 , and for the the four low-kink waves ππ1 varying process, see Figure 7. (1)d If (π, π) belongs to one of π΄ 3 , π΄ 7 , π΄ 8 , and π = ± √π 0 /12, then ππ± = ππ± = ππ0 . Specially, when 2 ± tend (π, π) ∈ π΄ 3 and π → 3π /16π − 0, then ππ0 to two trivial solutions π = ±√−(3π/4π). (2) For the case of π < 0, there are three properties as follows. (2)a If (π, π) ∈ π2 , that is, π > 0, π < 0, and ± π = 3π2 /16π, then ππ± and ππ± become ππ1 and ± ππ1 which represent four 1-blow-up waves (refer ± to Figure 8(d)). Specially, let π = π < 0, then ππ1 ± and ππ1 become the hyperbolic 1-blow-up wave ± and solutions ππ0 ± = ±√ ππ2 2π (−1 + coth (√ππ)). π (35) (2)b If (π, π) ∈ π΄ 3 and π =ΜΈ − √π 0 /12, then ππ± =ΜΈ ππ± , and they represent four 2-blow-up waves (refer to Figure 8(a)). Specially, when π → 3π2 /16π − 0, then the four 2-blow-up waves become four 1± ± and ππ1 , and for the varying blow-up waves ππ1 process, see Figure 8. Abstract and Applied Analysis 5 π π ππ+ ππ+ 0 0 π ππ− π ππ− ππ− (a) ππ− (b) π ππ+ ππ+ ππ+ π ππ+ 0 ππ+ 0 π ππ− π ππ− ππ− (c) (d) Figure 3: (The 2-blow-up waves are bifurcated from the periodic-blow-up waves.) The varying process for the figures of ππ± when (π, π) ∈ π΄ 2 and π → 0 − 0, where π = 1, π = −4 and (a) π = 0 − 1, (b) π = 0 − 0.5, (c) π = 0 − 0.1, and (d) π = 0 − 0.01. (2)c If (π, π) ∈ π΄ 3 and π = −√π 0 /12, then ππ± = ± of forms ππ± = πππ where ππ± = ± ± πππ = ±√ 12π −3π − √9π2 − 48ππ cosh (2√ππ) , 2 π½ = 2 2 (ππ± ) , π − ππ πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , (37) πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , , √((Δ − π) /2π) (2Δ + π − 2πππ ) √(2Δ + π)2 + 4ππ (4Δ − π) π−ππ + 4π2 π2 π−2ππ , π is a nonzero arbitrary real constant, Δ is given in (24), and 1 π = √ Δ (Δ − π). π (39) Let Proposition 2. If (π, π) belongs to one of the regions π΄ 1 , π΄ 2 , π΄ 3 , π΄ 4 , π΄ 11 , and π΄ 12 or curves π1 , π2 , π3 , π6 , and π7 , then (1) have four nonlinear wave solutions π’π± −ππ ππ± = ± 2.2. When the Orbit Γ Is Defined by π»(π,π¦)=π»(π1 ,0) π½ 2 π’π± = 2 2 (ππ± ) , π − ππ √(2Δ + π)2 + 4ππ (4Δ − π) πππ + 4π2 π2 π2ππ (38) (36) which represent hyperbolic blow-up waves. When ± π → 3π2 /16π − 0, then πππ tend to two trivial solutions π = ±√−(3π/4π). √((Δ − π) /2π) (2Δ + π − 2πππππ ) π0 = π + 2Δ . 2π (40) About π0 , one has the following fact: > 0 for (π, π) ∈ π΄ 1 , π΄ 2 , π΄ 3 , π3 , { { π0 {= 0 for (π, π) ∈ π2 , { {< 0 for (π, π) ∈ π΄ 4 , π΄ 11 , π΄ 12 , π1 , π6 , π7 . (41) Corresponding to π > 0 and π < 0, these solutions have the following properties and wave shapes. 6 Abstract and Applied Analysis π π + ππ0 + ππ0 0 0 π − ππ0 + ππ0 + ππ0 π − ππ0 − ππ0 − ππ0 (a) (b) π π + ππ0 + ππ0 + ππ0 0 − ππ0 0 π − ππ0 π − ππ0 (c) (d) ± Figure 4: (The symmetric solitary waves are bifurcated from the symmetric periodic waves.) The varying process for the figures of ππ0 when (π, π) ∈ π΄ 12 and π → 0 − 0, where π = −1, π = 4 and (a) π = 0 − 0.5, (b) π = 0 − 0.1, (c) π = 0 − 0.01, and (d) π = 0 − 0.001. (1o ) For the case of π > 0, there are six properties as follows. (1 )a If (π, π) ∈ π2 , that is, π > 0, π < 0, and π = 3π2 /16π, then ππ± and ππ± become o β = β√ ππ1 β ππ1 4ππ 16ππ−2√ππ = β√ − ππ 4ππ 16ππ2√ππ − ππ , , (42) (43) which represent four low-kink waves (refer to Figure 9(d)). Specially, let π = −(16π/π) > 0, β β β β = ππ0 and ππ1 = ππ0 . then ππ1 (1o )b If (π, π) ∈ π΄ 1 , π΄ 2 , π΄ 3 , and π =ΜΈ |π0 |, then ππ± =ΜΈ ππ± , and they represent four tall-kink waves (refer to Figure 9(a)). Specially, when (π, π) ∈ π΄ 3 and β π → 3π2 /16π − 0, then ππ± and ππ± become ππ1 β and ππ1 , and for the varying process, see Figure 9. (1o )c If (π, π) ∈ π΄ 4 , π΄ 11 , π΄ 12 , π6 , and π =ΜΈ |π0 |, then ππ± =ΜΈ ππ± . When (π, π) ∈ π΄ 4 , they represent four antisymmetric solitary waves (refer to Figure 10(a)). When (π, π) ∈ π΄ 11 , π΄ 12 , and π6 , they represent four symmetric solitary waves (refer to Figure 11(a)). Specially, when (π, π) ∈ π΄ 4 , if π → 3π2 /16π + 0, then ππ± and ππ± β β become ππ1 and ππ1 , and for the varying process, see Figure 10. When (π, π) ∈ π΄ 11 and π → π2 /4π + 0, then ππ± and ππ± tend to two trivial solutions π = ±√−(π/2π), and for the varying process, see Figure 11. o (1 )d If (π, π) ∈ π΄ 3 and π = |π0 |, then ππ± = ππβ = ππβ of forms ππβ = β √(1/π) (Δ − π) (2Δ + π) sinh ((π/2) π) √−π + 4Δ + (π + 2Δ) cosh (ππ) , (44) which represent two tall-kink waves and tend to a trivial wave π = 0 when π → 3π2 /16π − 0. o (1 )e If (π, π) ∈ π΄ 4 and π = |π0 |, then ππ± = ππ± = πββ of forms πββ = β √(1/π) (Δ − π) (2Δ + π) cosh ((π/2) π) √π − 4Δ + (π + 2Δ) cosh (ππ) , (45) which represent two antisymmetric solitary waves, tend to a trivial wave π = 0 when π → 3π2 /16π + 0, and tend to two trivial waves π = ±√−(π/2π) when π → π2 /4π − 0. o (1 )f If (π, π) ∈ π΄ 11 , π΄ 12 , π6 and π = |π0 |, then ππ± = ππ± = πβ± which represent two symmetric solitary waves. Specially, when (π, π) ∈ π΄ 11 and π → π2 /4π − 0, then πβ± tend to two trivial waves π = ±√−(π/2π). Abstract and Applied Analysis 7 π π + ππ0 + ππ0 ππ+ 0 0 π − ππ0 ππ+ ππ− π − ππ0 (a) ππ− (b) π π + ππ0 + ππ0 = ππ+ ππ+ 0 0 π − ππ0 ππ− π − ππ0 = ππ− (c) (d) ± Figure 5: (The symmetric periodic waves become two trivial waves.) The varying process for the figures of ππ0 and ππ± when (π, π) ∈ π΄ 12 and 2 2 −1 −2 π → 3π /16π + 0, where π = −1, π = 4, and π6 : π = 3π /16π = −3 and (a) π = −3 + 10 , (b) π = −3 + 10 , (c) π = −3 + 10−3 , and (d) π = −3 + 10−6 . (2o ) For the case of π < 0, there are five properties as follows. ± ± (2o )a If (π, π) ∈ π2 , then ππ1 and ππ1 represent four 1blow-up waves (refer to Figure 12(d)). Specially, ± ± β = ππ0 and ππ± = ππ2 . let π = 16π/π < 0, then ππ1 (2o )b If (π, π) ∈ π΄ 1 , π΄ 2 , π΄ 3 , π΄ 4 and π =ΜΈ − |π0 |, then ππ± =ΜΈ ππ± , and they represent four pairs of 1-blow-up waves (refer to Figure 12(a)). In particular, when (π, π) ∈ π΄ 4, if π → 3π2 /16π + 0, then the four pairs of 1-blow-up waves become two pairs of 1-blow-up waves, and the varying process is displayed in Figure 12. If π → π2 /4π − 0, then the four pairs of 1-blow-up waves become two trivial waves π = ±√−(π/2π). (2o )c If (π, π) ∈ π΄ 11 , π΄ 12 , π6 and π =ΜΈ − |π0 |, then ππ± =ΜΈ ππ± , and they represent four tall-kink waves. (2o )d If π = −|π0 |, when (π, π) ∈ π΄ 3 , then ππ± = ππ± = πββ which represent two pairs of 1-blow-up waves. When (π, π) ∈ π΄ 4 , then ππ± = ππβ = ππβ which represent two pairs of 1-blow-up waves. (2o )e If (π, π) ∈ π΄ 11 , π΄ 12 , π6 and π = −|π0 |, then ππ± = ππβ = ππβ which represent two tall-kink waves. 2.3. When the Orbit Γ Is Defined by π»(π,π¦) = π»(π2 , 0) Proposition 3. (i) If (π, π) belongs to one of π΄ 3 , π΄ 4 , π΄ 11 , and π2 , then (1) have four nonlinear wave solutions π½ 2 π’π± = 2 2 (ππ± ) , πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , π − ππ (46) 2 π½ π’π± = 2 2 (ππ± ) , πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , π − ππ where ππ± = ±√ (π + Δ) (2Δ − π) π cos ( π) , 2 π (π + 4Δ + (π − 2Δ) cos (ππ)) (47) ππ± = ±√ (π + Δ) (2Δ − π) π sin ( π) , 2 π (π + 4Δ − (π − 2Δ) cos (ππ)) (48) 1 (49) π = √ (4ππ − π (π + Δ)). π When (π, π) ∈ π΄ 3 , π΄ 4 , or π2 , then ππ± and ππ± represent periodic blow-up wave solutions (refer to Figure 13(a)). When (π, π) ∈ π΄ 11 , then ππ± and ππ± represent periodic wave solutions (refer to Figure 14(a)). (ii) If (π, π) ∈ π1 or π7 , then (1) have two fractional wave solutions π½ 2 πΈπ± = ππ± ππ(πΎπ₯−ππ‘) , π’π± = 2 2 (ππ± ) , (50) π − ππ 8 Abstract and Applied Analysis π π ππ+ ππ+ ππ+ ππ+ 0 0 π ππ− ππ− π ππ− ππ− (a) (b) π π ππ+ ππ+ ππ+ 0 ππ+ 0 π ππ− ππ− π ππ− ππ− (c) (d) Figure 6: (The four low-kink waves are bifurcated from four symmetric solitary waves.) The varying process for the figures of ππ± and ππ± when (π, π) ∈ π΄ 3 , π > 0, π =ΜΈ √π 0 /12 and π → 3π2 /16π − 0, where π = 1, π = −4, π = 4, and π2 : π = 3π2 /16π = 3 and (a) π = 3 − 10−1 , (b) π = 3 − 10−3 , (c) π = 3 − 10−7 , and (d) π = 3 − 10−9 . where ππ± = ±√ −π ππ . 2π √π2 π2 − 12π (51) π1 , ππ± represent two 1-blow-up waves (refer When (π, π) ∈ to Figure 13(d)). When (π, π) ∈ π7 , ππ± represent two tall-kink waves (refer to Figure 14(d)). (iii) If (π, π) ∈ π΄ 4 and π → π2 /4π − 0, then the periodic blow-up waves ππ± tend to two trivial solutions π = ±√−(π/2π), while ππ± tend to the 1-blow-up waves ππ± , and the varying process is displayed in Figure 13. If (π, π) ∈ π΄ 11 and π → π2 /4π + 0, then the periodic waves ππ± tend to two trivial solutions π = ±√−(π/2π), while ππ± tend to the tall-kink waves ππ± , and for the varying process, see Figure 14. 3. The Derivations of Main Results To derive our results, substituting (23) and π’(π₯, π‘) = π’(π) with π = π₯ − ππ‘ into (1), it follows that σΈ σΈ (π2 − ππ 2 ) π’σΈ σΈ = π½(π2 ) , πΌπσΈ σΈ + π (2πΌπΎ − π) πσΈ + (π€ − πΌπΎ2 ) π − πΏ1 π’π + πΏ2 π3 + πΏ3 π5 = 0. (52) Integrating the first equation of (52) twice with respect to π and taking the integral constants to zero, we get (22). Substituting (22) into the second equation of (52) and letting π = 2πΌπΎ, it follows that πσΈ σΈ = ππ + ππ3 + ππ5 . (53) Form (53) we obtain the planar system ππ = π¦, ππ ππ¦ = ππ + ππ3 + ππ5 , ππ (54) with the first integral π π π» (π, π¦) = π¦2 − (ππ2 + π4 + π6 ) = β. 2 3 (55) According to the qualitative theory, we obtain the bifurcation phase portraits of system (54) as Figures 15 and 16. Using the information given by Figures 15 and 16, we give derivations to Propositions 1, 2, and 3, respectively. 3.1. The Derivations to Proposition 1. When the orbit Γ is defined by π»(π, π¦) = π»(0, 0), from (55) we obtain π π π¦ = ±√ ππ2 + π4 + π6 . 2 3 (56) Abstract and Applied Analysis 9 π ππ+ π ππ+ ππ+ ππ+ 0 0 π ππ− ππ− ππ− ππ− (a) (b) π ππ+ π π ππ+ 0 ππ+ ππ+ 0 π ππ− π ππ− ππ− ππ− (c) (d) Figure 7: (The four low-kink waves are bifurcated from four 1-blow-up waves.) The varying process for the figures of ππ± and ππ± when (π, π) ∈ π΄ 4 , π > 0, π =ΜΈ √π 0 /12, and π → 3π2 /16π + 0, where π = 1, π = −4, π = 4, and π2 : π = 3π2 /16π = 3 and (a) π = 3 + 10−1 , (b) π = 3 + 10−3 , (c) π = 3 + 10−6 , and (d) π = 3 + 10−9 . Substituting (56) into the first equation of (54) and integrating it, we have ∫ π π ππ √ππ 2 + (π/2) π 4 + (π/3) π 6 = π, (57) Thus, we have lim π± π → 0−0 π0 where π is an arbitrary constant or ±∞. For π = 0, letting π = √−(3π/2π) or ±∞ and completing the above integral, it follows that π = ±√ 6π , 3π2 π2 − 4π = lim ± √ −12π π (π) = ±√ lim −12 (π) π → 0−0 π → 0−0 πσΈ = ± ( lim (2√9π2 − 48ππ π → 0−0 × ( (3π2 − 16ππ) π2 (58) × (sin (2√−ππ) /2√−ππ) which yields ππ± as (29). For π < 0, completing (57) and solving for π, it follows that π = ±√ −12π 3π − √9π2 − 48ππ sin (π + 2√−ππ) , (59) where π = π(π) is an arbitrary real constant. Let π = ±(π/2), ± and ππ± as (3) and respectively, and we obtain the solutions ππ0 (31). When (π, π) ∈ π΄ 1 , that is, π > 0, π > 0, and π < 0, let π (π) = 3π − √9π2 − 48ππ cos (2√−ππ) , (60) π (π) = 3π + √9π2 − 48ππ cos (2√−ππ) . −1 1/2 −4π cos (2√−ππ) ) ) ) = ±√ = ππ± lim π± π → 0−0 π 6π − 4π (see (29)) , 3π2 π2 = lim ± √ π → 0−0 = ±√ lim −12π π (π) −12π π → 0−0 π (π) = 0. (61) 10 Abstract and Applied Analysis π π ππ+ ππ+ ππ+ ππ+ 0 0 π ππ− π ππ− ππ− ππ− (a) (b) π π ππ+ ππ+ ππ+ ππ+ 0 0 π ππ− π ππ− ππ− (c) ππ− (d) Figure 8: (The four 2-blow-up waves become four 1-blow-up waves.) The varying process for the figures of ππ± and ππ± when (π, π) ∈ π΄ 3 , π < 0, π =ΜΈ − √π 0 /12, and π → 3π2 /16π − 0, where π = 1, π = −4, π = −4, and π2 : π = 3π2 /16π = 3 and (a) π = 3 − 10−1 , (b) π = 3 − 10−3 , (c) π = 3 − 10−6 , and (d) π = 3 − 10−9 . When (π, π) ∈ π΄ 2 , that is, π > 0, π < 0, and π < 0, similarly we get lim π± π → 0−0 π = ππ± . (62) When (π, π) ∈ π΄ 12 , that is, π < 0, π > 0, and π < 0, if π → 3π2 /16π + 0, then π(π) and π(π) → 0. Thus, ± (or ππ± ) = ±√ − lim ππ0 π → 0−0 For the case of π > 0. When (π, π) ∈ π2 , that is, π > 0, π < 0 and π = 3π2 /16π. In (33) letting π = 3π2 /16π, we get (34). Furthermore, in (34) letting π = −π > 0, it follows that 3π . 4π + 1) 4ππ−√ππ −π (π√ππ + π−√ππ ) = ±√ 2π π√ππ − π−√ππ (1 − √ππ −√ππ ) −π π +π = ±√ 2π (1 − tanh (√ππ)) −π = ±√ 2π (−1 + tanh (√ππ)) π (64) where π = π(π) is an arbitrary real constant. Note that if π(π) is a solution of (53), so is π(−π). Thus, from (64) we obtain the solutions ππ± and ππ± as in (33). 4π −π (π2√ππ = ±√ (63) For π > 0, completing (57) and solving for π, it follows that 4πππ2√ππ , π = ±√ 2 4√ππ ππ + (π2 /4 − 4ππ/3) − πππ2√ππ ± ππ1 = ±√ ± = ππ0 (see (4)) , Abstract and Applied Analysis 11 π π ππ+ ππ+ ππ+ 0 ππ− ππ+ 0 π π ππ− ππ− ππ− (a) (b) π π ππ− ππ− ππ+ ππ+ 0 ππ− ππ− 0 π π ππ+ ππ+ (c) (d) Figure 9: (The four low-kink waves are bifurcated from the four tall-kink waves.) The varying process for the figures of ππ± and ππ± when π > 0, π =ΜΈ |π0 |, (π, π) ∈ π΄ 3 , and π → 3π2 /16π − 0, where π = 1, π = −4, π2 : π = 3π2 /16π = 3, and π = 4 and (a) π = 3 − 0.5, (b) π = 3 − 10−2 , (c) π = 3 − 10−4 , and (d) π = 3 − 10−6 . ± ππ1 = ±√ For the case of π < 0, similarly we can obtain (7), (35), and (36), and here we omit the process. Hereto, we have completed the derivations for Proposition 1. 4π −π (π−2√ππ + 1) = ±√ 4ππ√ππ −π (π√ππ + π−√ππ ) = ±√ 2π π√ππ − π−√ππ (1 + √ππ −√ππ ) −π π +π = ±√ 2π (1 + tanh (√ππ)) −π = ±√ 2π ± (−1 − tanh (√ππ)) = ππ0 (see (5)) . π 3.2. The Derivations to Proposition 2. When the orbit Γ is defined by π»(π, π¦) = π»(π1 , 0), from (55) we obtain π π π¦ = ±√ ππ2 + π4 + π6 + π» (π1 , 0) 2 3 π 2 = ±√ (π12 − π2 ) (π2 + π0 ), 3 (65) When π = √π 0 /12, by (33) it follows that ππ± = ππ± = ±√ = ±√ −6π + √9π2 − 48ππ (π√ππ + π−√ππ ) −3π + π ππ π √(π/3) (π12 − π 2 )2 (π 2 + π0 ) = π, (68) where π is an arbitrary constant or ±∞. Completing the above integral and solving for π, it follows that 12π √9π2 where π1 and π0 are given in (25) and (40). Substituting (67) into the first equation of (54) and integrating it, we have ∫ 24π (67) − 48ππ cosh (2√ππ) ± = ππ0 (see (6)) . (66) π = ±√ π12 − π2 π2ππ 4π1 ππππ , − 2ππ1 πππ + π12 − 4π1 (69) 12 Abstract and Applied Analysis π π ππ− ππ− ππ− 0 0 π ππ+ ππ+ ππ− π ππ+ ππ+ (a) (b) π π ππ− ππ− ππ− ππ− 0 ππ+ ππ+ 0 π π ππ+ (c) ππ+ (d) Figure 10: (The four low-kink waves are bifurcated from the four antisymmetric solitary waves.) The varying process for the figures of ππ± and ππ± when π > 0, π =ΜΈ |π0 |, (π, π) ∈ π΄ 4 , and π → 3π2 /16π + 0, where π = 1, π = −4, π2 : π = 3π2 /16π = 3, and π = 4 and (a) π = 3 + 10−1 , (b) π = 3 + 10−3 , (c) π = 3 + 10−5 , and (d) π = 3 + 10−7 . where π is given in (39), π = π(π) is an arbitrary constant, and 3Δ (Δ − π) , π1 = 4π2 π − 4Δ π1 = . 2π −4π = β√ π (1 + π−2√ππ ) = β√ 2π (−1 − tanh (√ππ)) π (71) If (π, π) ∈ π΄ 3 and π = |π0 |, that is, π > 0, π = π0 > 0, and 2Δ + π > 0, we have ππ± =± =± =± β = ππ0 (see (5)) , β ππ1 −4π = β√ π (1 + π2√ππ ) 2π (−1 + tanh (√ππ)) π β = ππ0 (see (4)) . (70) Similar to the derivations for ππ± and ππ± , we get ππ± and ππ± (see (38)) from (69). For the case of π > 0, when (π, π) ∈ π2 , that is, π > 0, π < 0, and π = 3π2 /16π, then π = 2√π and π + 2Δ = 0. From β (38) and (41), it is easy to check that ππ± and ππ± become ππ1 β and ππ1 (see (42)), respectively. Furthermore, in (42) letting π = −(16π/π), it follows that β ππ1 = β√ =± √(Δ − π) /2π (2Δ + π − 2πππππ ) √(2Δ + π)2 + 4ππ (4Δ − π) πππ + 4π2 π2 π2ππ √(Δ − π) /2π (2Δ + π) (1 − πππ ) √(π + 2Δ)2 + 2 (π + 2Δ) (4Δ − π) πππ + (π + 2Δ)2 π2ππ √(1/2π) (Δ − π) (2Δ + π) (1 − πππ ) √π + 2Δ + 2 (4Δ − π) πππ + (π + 2Δ) π2ππ √(1/2π) (Δ − π) (2Δ + π) (π−ππ/2 − πππ/2 ) √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) Abstract and Applied Analysis 13 π ππ+ ππ+ 0 ππ+ 0 π ππ− ππ− ππ+ π ππ+ π ππ− ππ− (a) (b) π π ππ+ ππ+ = ππ+ 0 0 π π ππ− = ππ− ππ− ππ− (c) (d) Figure 11: (The four symmetric solitary waves become two trivial waves.) The varying process for the figures of ππ± and ππ± when π > 0, π =ΜΈ |π0 |, (π, π) ∈ π΄ 11 , and π → π2 /4π + 0, where π = −1, π = 4, π7 : π = π2 /4π = −4, and π = 1 and (a) π = −3.5, (b) π = −4 + 10−1 , (c) π = −4 + 10−2 , and (d) π = −4 + 10−5 . =β If (π, π) ∈ π΄ 4 and π = |π0 |, that is, π > 0, π = −π0 > 0, and 2Δ + π < 0, we have √(1/π) (Δ − π) (2Δ + π) sinh ((π/2) π) √−π + 4Δ + (π + 2Δ) cosh (ππ) ππ± = ππβ (see (44)) , ππ± =± =± =± =± =± =± √(Δ − π) /2π (2Δ + π − 2πππ−ππ ) √(2Δ + π)2 + 4ππ (4Δ − π) π−ππ + 4π2 π2 π−2ππ √(Δ − π) /2π (2Δ + π) (1 − π 2 √(π + 2Δ) + 2 (π + 2Δ) (4Δ − π) π−ππ −ππ ) + (π + =± 2 2Δ) π−2ππ √(1/2π) (Δ − π) (2Δ + π) (1 − π−ππ ) =β √π + 2Δ + 2 (4Δ − π) π−ππ + (π + 2Δ) π−2ππ √(1/2π) (Δ − π) (2Δ + π) (πππ/2 − π−ππ/2 ) =β √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) √(1/π) (Δ − π) (2Δ + π) sinh ((π/2) π) =β √−π + 4Δ + (π + 2Δ) cosh (ππ) = ππ± (see (44)) . (72) √(Δ − π) /2π (2Δ + π − 2πππππ ) √(2Δ + π)2 + 4ππ (4Δ − π) πππ + 4π2 π2 π2ππ √(Δ − π) /2π (2Δ + π) (1 + πππ ) √(π + 2Δ)2 + 2 (π + 2Δ) (4Δ − π) πππ + (π + 2Δ)2 π2ππ √(1/2π) (Δ − π) (2Δ + π) (1 + πππ ) √π + 2Δ + 2 (4Δ − π) πππ + (π + 2Δ) π2ππ √(1/2π) (Δ − π) (2Δ + π) (π−ππ/2 + πππ/2 ) √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) √(1/π) (Δ − π) (2Δ + π) cosh ((π/2) π) √−π + 4Δ + (π + 2Δ) cosh (ππ) = πββ (see (45)) , 14 Abstract and Applied Analysis π ππ− ππ+ π ππ+ ππ− ππ− 0 ππ+ ππ− ππ− ππ− ππ+ ππ+ ππ− ππ+ (b) π π ππ+ ππ+ ππ− ππ− ππ+ ππ+ 0 π ππ− π ππ− (a) ππ+ ππ− 0 π 0 ππ+ ππ+ ππ− ππ+ (c) π ππ− (d) Figure 12: (The two pairs of 1-blow-up waves are bifurcated from the four pairs of 1-blow-up waves.) The varying process for the figures of ππ± and ππ± when π < 0, π =ΜΈ − |π0 |, (π, π) ∈ π΄ 4 , and π → 3π2 /16π + 0, where π = 1, π = −4, π2 : π = 3π2 /16π = 3, and π = −4 and (a) π = 3 + 10−2 , (b) π = 3 + 10−4 , (c) π = 3 + 10−6 , and (d) π = 3 + 10−9 . ππ± =± =± =β If (π, π) ∈ π΄ 11 , π΄ 12 , π6 and π = |π0 |, that is, π < 0, π = −π0 > 0, and 2Δ + π > 0, we have √(Δ − π) /2π (2Δ + π − 2πππ−ππ ) ππ± √(2Δ + π)2 + 4ππ (4Δ − π) π−ππ + 4π2 π2 π−2ππ =± √(Δ − π) /2π (2Δ + π) (1 + π−ππ ) √(π + 2Δ)2 + 2 (π + 2Δ) (4Δ − π) π−ππ + (π + 2Δ)2 π−2ππ =± √(1/2π) (Δ − π) (2Δ + π) (1 + π−ππ ) √π + 2Δ + 2 (4Δ − π) π−ππ + (π + 2Δ) π−2ππ =± =β =β √(Δ − π) /2π (2Δ + π − 2πππππ ) √(2Δ + π)2 + 4ππ (4Δ − π) πππ + 4π2 π2 π2ππ √(Δ − π) /2π (2Δ + π) (1 + πππ ) √(π + 2Δ)2 + 2 (π + 2Δ) (4Δ − π) πππ + (π + 2Δ)2 π2ππ √(1/2π) (Δ − π) (2Δ + π) (1 + πππ ) √(1/2π) (Δ − π) (2Δ + π) (π−ππ/2 + πππ/2 ) √π + 2Δ + 2 (4Δ − π) πππ + (π + 2Δ) π2ππ √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) √(1/2π) (Δ − π) (2Δ + π) (π−ππ/2 + πππ/2 ) =± √(1/π) (Δ − π) (2Δ + π) cosh ((π/2) π) √−π + 4Δ + (π + 2Δ) cosh (ππ) =± = πββ (see (45)) . (73) √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) √(1/π) (Δ − π) (2Δ + π) cosh ((π/2) π) √−π + 4Δ + (π + 2Δ) cosh (ππ) = πβ± (see (45)) , Abstract and Applied Analysis 15 π ππ+ ππ+ ππ− 0 ππ− π ππ+ ππ− 0 π ππ+ ππ− ππ+ (b) π π ππ+ ππ− 0 ππ+ π ππ− ππ+ ππ+ (a) ππ− ππ+ ππ− ππ+ 0 π ππ− ππ− ππ+ (c) π (d) Figure 13: (The 1-blow-up waves are bifurcated from the periodic blow-up waves.) The varying process for the figures of ππ± when (π, π) ∈ π΄ 4 and π → π2 /4π − 0, where π = 1, π = −4, and π1 : π = π2 /4π = 4 and (a) π = 4 − 10−1 , (b) π = 4 − 10−2 , (c) π = 4 − 10−4 , and (d) π = 4 − 10−6 . ππ± =± =± =± =± =± the process. Hereto, we have completed the derivations for Proposition 2. √(Δ − π) /2π (2Δ + π − 2πππ−ππ ) 3.3. The Derivations to Proposition 3. When the orbit Γ is defined by π»(π, π¦) = π»(π2 , 0), firstly, if (π, π) belongs to one of π΄ 3 , π΄ 4 , π΄ 11 , and π2 , then from (55) we obtain √(2Δ + π)2 + 4ππ (4Δ − π) π−ππ + 4π2 π2 π−2ππ √(Δ − π) /2π (2Δ + π) (1 + π−ππ ) √(π + 2Δ)2 + 2 (π + 2Δ) (4Δ − π) π−ππ + (π + 2Δ)2 π−2ππ √(1/2π) (Δ − π) (2Δ + π) (1 + π−ππ ) π π π¦ = ±√ ππ2 + π4 + π6 + π» (π2 , 0) 2 3 π 2 = ±√ (π2 − π22 ) (π2 + πΏ0 ), 3 √π + 2Δ + 2 (4Δ − π) π−ππ + (π + 2Δ) π−2ππ (75) where π2 is given in (16) and πΏ0 = (π − 2Δ)/2π. Substituting (75) into the first equation of (54) and integrating it, we have √(1/2π) (Δ − π) (2Δ + π) (π−ππ/2 + πππ/2 ) √2 (4Δ − π) + (π + 2Δ) (π−ππ + πππ ) ∫ √(1/π) (Δ − π) (2Δ + π) cosh ((π/2) π) π π √−π + 4Δ + (π + 2Δ) cosh (ππ) = πβ± (see (45)) . (74) For the case of π < 0, similarly we can obtain the relations of the solutions ππ± , ππ± , ππ± , and πβ± , and here we omit ππ √(π/3) (π 2 − π22 )2 (π 2 + πΏ0 ) = π, (76) where π is an arbitrary constant or ±∞. Completing the above integral and solving for π, it follows that π = ±√π22 − 2π2 , π2 + πΏ0 sin (πΏ + ππ) (77) 16 Abstract and Applied Analysis π π ππ− 0 0 π ππ− ππ+ ππ+ ππ− ππ+ π ππ+ ππ− (a) (b) π π ππ+ ππ+ 0 0 π π ππ− ππ− (c) (d) Figure 14: (The two tall-kink waves are bifurcated form two periodic waves.) The varying process for the figures of ππ± when (π, π) ∈ π΄ 11 and π → π2 /4π + 0, where π = −1, π = 4, and π7 : π = π2 /4π = −4 and (a) π = −3.5, (b) π = −4 + 10−1 , (c) π = −4 + 10−3 , and (d) π = −4 + 10−5 . where π is given in (49), πΏ = πΏ(π) is an arbitrary constant, and π2 = 3Δ (Δ + π) , 4π2 π2 = − π + 4Δ . 2π When π → π2 /4π, it follows that Δ = √π2 − 4ππ σ³¨→ 0, (78) In (77) letting πΏ = ±(π/2), respectively, we obtain the solutions ππ± and ππ± as (47) and (48). Secondly, if (π, π) ∈ π1 or π7 , that is, Δ = 0 and π12 = −πΏ0 = −(π/2π), thus from (75), we obtain Δ (Δ + π) 1 π = √ (4ππ − π (π + Δ)) = √ − σ³¨→ 0, π π (81) cos (ππ) = 1 − =1+ π 3 π π¦ = ±√ (π2 + ) . 3 2π which yields ππ± as in (51). ππ ππ + + ⋅⋅⋅ 2 4! Δ (Δ + π) 2 π + π (Δ2 ) . 2π Thus, we have lim2 π → (π /4π) −π ππ , 2π √π2 π2 − 12π 4 4 (79) Similarly, we have π = ±√ 2 2 (80) ππ± = ± lim2 √ π → π /4π = ±√ (π + Δ) (2Δ − π) π cos ( π) 2 π (π + 4Δ + (π − 2Δ) cos (ππ)) π −π2 = ±√ − , 2ππ 2π Abstract and Applied Analysis 17 π π1 π¦ π¦ π2 −π1 −π2 π2 π1 π π π¦ π π¦ π¦ −π1 −π2 π2 π1 π π¦ π −π1 π¦ −π1 −π2 π2 π1 π1 π π΄4 π¦ π3 π −π1 π1 π΄5 π΄6 π΄3 π π π΄2 π΄1 π¦ π4 π π π¦ π¦ −π1 −π1 π1 π1 π¦ π π −π1 π1 π Figure 15: The bifurcation phase portraits of system (54) for π > 0. 2 lim ππ± = π → π2 /4π lim2 π → π /4π (π + Δ) (2Δ − π) π = lim2 ± √ sin ( π) 2 π → π /4π π (π + 4Δ − (π − 2Δ) cos (ππ)) = = ±√ lim ± ( (− (π + Δ) (2Δ − π) π → π2 /4π (Δ + π) (2Δ − π) 2 π + π (Δ)) 2π × (2π [6 − (π − 2Δ) (1 + (π + Δ) (2Δ − π) (1 − cos (ππ)) 2π (π + 4Δ − (π − 2Δ) cos (ππ)) lim2 π → π /4π ± ((− −1 1/2 +π (Δ) ] ) ) Δ (Δ + π) 2 π 2π = ±√ 2 +π (Δ) ) × (2π [π + 4Δ − (π − 2Δ) × (1 + Δ (Δ + π) 2 π) 2π Δ (Δ + π) 2 π) 2π −1 +π (Δ2 ) ] ) ) 1/2 = ±√ (π3 /2π) π2 2π (6 − (π2 /2π) π2 ) −π ππ 2π √π2 π2 − 12π = ππ± (see (51)) . (82) Hereto, we have completed the derivations for our main results. 18 Abstract and Applied Analysis π π¦ −π2 π¦ π¦ π2 −π2 π π2 −π2 π π¦ π2 π π¦ π΄8 π΄7 π π π΄9 −π2 π΄ 12 π΄ 10 π2 π5 π π¦ π΄ 11 π¦ π1 −π2 −π1 π¦ π −π2 π π¦ π2 π π¦ π2 π1 −π2 −π1 π2 π π π¦ π¦ π6 −π2 −π1 π π1 π2 π π7 Figure 16: The bifurcation phase portraits of system (54) for π < 0. 4. Conclusions In this paper, we have investigated the explicit expressions of the nonlinear waves and bifurcation phenomena in (1). Firstly, we obtained three types of explicit nonlinear wave solutions. The first type is the fractional expressions ππ± and ππ± (see (29) and (51)). The second type is the trigonometric expressions ππ± and ππ± (see (47) and (48)). The third type is the exp-function expressions ππ± , ππ± , ππ± , and ππ± (see (33) and (38)). Secondly, we revealed five kinds of interesting bifurcation phenomena in (1). The first phenomena is that the 1-blowup waves can be bifurcated from the periodic-blow-up (see Figure 2 or Figure 13) and 2-blow-up waves (see Figure 8). The second phenomena is that the 2-blow-up waves can be bifurcated from the periodic-blow-up waves (see Figure 3). The third kind is that the symmetric solitary waves can be bifurcated from the symmetric periodic waves (see Figure 4). The fourth kind is that the low-kink waves can be bifurcated from the symmetric solitary waves (see Figure 6), the 1-blowup waves (see Figure 7), the tall-kink waves (see Figure 9), and the antisymmetric solitary waves (see Figure 10). The fifth kind is that the tall-kink waves can be bifurcated from the symmetric periodic waves (see Figure 14). Thirdly, we showed that some previous results are our ± ± ± , ππ0 , and ππ0 are included in special cases. For instants, ππ0 ± ± ± ± ± are ππ , ππ , ππ , and ππ (see (4), (5), (7), (33), and (38)). ππ0 ± ± included in ππ and ππ (see (6) and (33)). Finally, we employed the software Mathematica to check the correctness of these solutions. For example, the commands for π’π and πΈπ are as follows: π€ = πΌπΎ2 , π = (πΌπΎ2 − π€)/πΌ, π = π½πΏ1 /πΌ(π2 − ππ 2 ) − πΏ2 /πΌ, π = −πΏ3 /πΌ, π = 2πΌπΎ, π = π₯ − ππ‘, ππ = √6π/(3π2 π2 − 4π), Abstract and Applied Analysis 19 π’π = (π½/(π2 − ππ 2 ))ππ2 , πΈπ = ππ Exp[π(πΎπ₯ − π€π‘)], Simplify[D[π’π ,{π‘, 2}] − ππ 2 D[π’π ,{π₯, 2}] − π½D[ππ2 ,{π₯, 2}]] Simplify[πD[πΈπ , π‘] + πΌD[πΈπ , {π₯, 2}] − πΏ1 π’π πΈπ + πΏ2 ππ2 πΈπ + πΏ3 ππ4 πΈπ ] [13] [14] 0 0 [15] Acknowledgment This paper is supported by the National Natural Science Foundation (no. 11171115), Natural Science Foundation of Guangdong Province (no. S2012040007959) and the Fundamental Research Funds for the Central Universities (no. 2012ZM0057). References [1] G.-T. Liu and T.-Y. Fan, “New applications of developed Jacobi elliptic function expansion methods,” Physics Letters A, vol. 345, no. 1–3, pp. 161–166, 2005. [2] S. Liu, Z. Fu, S. 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