一类非线性演化方程的新多级准确解

在Lamé方程和新的Lamé函数的基础上，应用小扰动方法和Jacobi椭圆函数展开法求解一类非线性演化方程（如mKdV方程，非线性Klein-Gordon方程Ⅱ等），获得多种新的多级准确解 .这些多级准确解对应着不同形式的周期波解.这些解在极限条件下可以退化为多种形式的孤 立波解，如带状孤立子、钟形孤立子等. 关键词： Jacobi椭圆函数 Lam函数 多级准确解 非线性演化方程 扰动方法     

KdV-Burgers方程行波解的稳定性

对KdV-Burgers方程的行波解进行线性稳定性分析,数值结果表明：对于正耗散情形,其行波解是稳定的;对于负耗散情形,其行波解是不稳定的.其次构造有限差分法对其行波解进行非线性动力学演化,结果表明：对于正耗散情形,KdV-Burgers方程的行波解是稳定的.本文结果修正和完善了相关文献中所得结论.     

非线性波方程求解的新方法

从Legendre椭圆积分和Jacobi椭圆函数的定义出发，得到了新的变换，并把它用于非线性演化方程的求解.用三个具体的例子，如非线性Klein-Gordon方程、Boussinesq方程和耦合的mKdV方程组，说明了具体的求解步骤.比较方便地得到非线性演化方程或方程组的新解析解，如周期解、孤子解等. 关键词： Jacobi椭圆函数 非线性方程 周期解 孤子解     

一类五阶非线性演化方程的新孤波解

利用齐次平衡法给出了一类较广泛的五阶非线性演化方程的孤波解，数学物理中著名的Kaup-Kupershmidt方程、Caudrey-Dodd-Gibbon-Sawada-Kotera方程和五阶Korteweg-de-Vries方程等都可作为该方程的特殊情形而得到相应的孤波解. 关键词：     

柱和球尘埃离子声孤波的绝热近似解

通过运用等价粒子理论，得到了尘埃声孤波中的KdV类型方程（包括KdV方程，柱KdV方程和球KdV方程）的绝热近似解。这种方法也可以运用到其它的非线性演化方程。     

非线性演化方程孤立波的同伦分析法求解

利用同伦分析法求解了Burgers方程，得到了其扭结形孤立波的近似解析解，该解非常接近于相应的精确解.结果表明，同伦分析法可用来求解非线性演化方程的孤立波解.同时，也对所用方法进行了一定扩展，得到了Kadomtsev-Petviashvili(KP)方程的钟形孤立子解.经过扩展后的方法能够更方便地用于求解更多非线性演化方程的高精度近似解析解. 关键词： Burgers方程 同伦分析法 KP方程 孤立波解     

时变偏微分方程的贝叶斯稀疏识别方法

在数据驱动的建模中,通过测量或模拟得到时空数据,我们发现基于拉普拉斯先验的贝叶斯稀疏识别方法能有效地恢复时变偏微分方程的稀疏系数.本文将贝叶斯稀疏识别方法运用于各种时变偏微分方程模型(KdV方程、Burgers方程、Kuramoto-Sivashinsky方程、反应-扩散方程、非线性薛定谔方程和纳维-斯托克斯方程)的方...     

一类非线性演化方程新的显式行波解

借助Mathematica软件,采用三角函数法和吴文俊消元法,获得了一类非线性演化方程u_tt+au_xx+bu+cu³=0的三组行波解,其中包括新的行波解、扭状孤波解和钟状孤波解.从而作为该方程的特例,如Duffing方,Klein-Gordon方程、Landau-Ginburg-Higgs方程和⁴方程等也都获得了相应的若干行波解.这种方法也适用于其他非线性方程. 关键词：     

sine-Gordon型方程的无穷序列新精确解

为了获得sine-Gordon型方程的无穷序列精确解,给出三角函数型辅助方程和双曲函数型辅助方程及其Bäcklund变换和解的非线性叠加公式,借助符号计算系统Mathematica,构造了sine-Gordon方程、mKdV-sine-Gordon方程、(n+1)维双sine-Gordon方程和sinh-Gordon方程的无穷序列新精确解.其中包括无穷序列三角函数解、无穷序列双曲函数解、无穷序列Jacobi椭圆函数解和无穷序列复合型解. 关键词： sine-Gordon型方程 解的非线性叠加公式 辅助方程 无穷序列精确解     

非线性Schr(o)dinger方程的动力学行为分析

采用辛算法数值求解非线性Schrodinger方程的周期初值问题,建立不同的相空间来分析其动力学特性.首先比较分析了不同的相空间中立方非线性Schrodinger方程在不同立方非线性参数下的长时间演化的动力学特性,然后讨论了相空间中立方-五次方非线性Schrodinger方程在不同立方和五次方非线性参数下的长时间演化的动力学特性,数值结果显示,对于不同的立方非线性参数,随着五次方非线性参数的增加,动力学行为的演化路径是不一样的.     

Extended Homogeneous Balance Method and Lax Pairs, Backlund Transformation

Using the extended homogeneous balance method, which is very concise and primary, Lax pairs and Backlund transformation for most nonlinear evolution equations, such as the compound KdV-Burgers equation and nonlinear diffusion equation are obtained.     

Some New Solitary Wave Solutions to a Compound KdV-Burgers Equation

In terms of the solutions of an auxiliary ordinary differential equation, a new algebraic method, which contains the terms of first-order derivative of functions f(ξ), is constructed to explore the new solitary wave solutions for nonlinear evolution equations. The method is applied to a compound KdV-Burgers equation, and abundant new solitary wave solutions are obtained. The algorithm is also applicable to a large variety of nonlinear evolution equations.     

一个新的广义的Riccati方程有理展开法及其应用

利用符号计算软件Maple,在一个新的广义的Riccati方程有理展开法的帮助下,得到了关于复合的KdV系统及广义的KdV-Burgers系统的几个新的更广义类型的精确解.该方法还可被应用到其他非线性发展方程中去.     

Lienard Equation and Exact Solutions for Some Soliton-Producing Nonlinear Equations

In this paper, we first consider exact solutions for Lienard equation with nonlinear terms of any order. Then, explicit exact bell and kink profile solitary-wave solutions for many nonlinear evolution equations are obtained by means of results of the Lienard equation and proper deductions, which transform original partial differential equations into the Lienard one. These nonlinear equations include compound KdV, compound KdV-Burgers, generalized Boussinesq, generalized KP and Ginzburg-Landau equation. Some new solitary-wave solutions are found.     

Trial Equation Method to Nonlinear Evolution Equations with Rank Inhomogeneous:Mathematical Discussions and Its Applications

A trial equation method to nonlinear evolution equation with rank inhomogeneous is given. As applications, the exact traveling wave solutions to some higher-order nonlinear equations such as generalized Boussinesq equation, generalized Pochhammer-Chree equation, KdV-Burgers equation, and KS equation and so on, are obtained. Among these, some results are new. The proposed method is based on the idea of reduction of the order of ODE. Some mathematical details of the proposed method are discussed.     

A New Asymptotic Approach to Solve Nonlinear Evolution Equations

A conformal-invariant asymptotic expansion approach to solve any nonlinear integrable and nonintegrable models with any dimensions is proposed. Taking the compound KdV-Burgers (cKdVB) equation and the KdV-Burgers (KdVB) equation as concrete examples,we obtain many new conformal-invariant models with Painleve' property and the approximate solutions of the cKdVB and KdVB equations. In some special cases, the approximate solutions become exact.     

Nonlinear Shock and Kink Waves with Complete Coriolis Force in Earth's Atmosphere

Nonlinear waves in a Boussinesq fluid model which includes both the vertical and horizontal components of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-wave solution. Taylor series expansion has been employed to isolate the characteristics of the linear Rossby waves and to identify the nonlinear shock and kink waves. The KdV-Burgers and the compound KdV-Burgers equations are derived, their shock wave and kink wave solution are also obtained.     

2-Soliton-Solution of the Novikov-Veselov Equation

Based on a superposition method recently proposed to obtain 1-solitary wave solutions of the KdV-Burgers equation (Yuanxi and Jiashi, 2005, International Journal of Theoretical Physics 44, 293–301), we show that this method can also be used to find a 2-solitary wave solution of the Novikov-Veselov equation. Thus, it seems that the method of Yuanxi and Jiashi in general is not restricted to constructing 1-solitary wave solutions of nonlinear wave and evolution equations (NLWEEs).     

New explicit and exact solutions for a compound KdV-Burgers equation

In this paper, new explicit and exact solutions for a compound KdV-Burgers equation are obtained using the hyperbolic function method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important cases of the equation, such as the compound KdV, mKdV-Burgers and mKdV equations can be solved by this method. The method can also be applied to solve other nonlinear partial differential equation and equations.     

Approximate solutions of nonlinear PDEs by the invariant expansion

<正>It is difficult to obtain exact solutions of the nonlinear partial differential equations(PDEs) due to their complexity and nonlinearity,especially for non-integrable systems.In this paper,some reasonable approximations of real physics are considered,and the invariant expansion is proposed to solve real nonlinear systems.A simple invariant expansion with quite a universal pseudopotential is used for some nonlinear PDEs such as the Korteweg-de Vries(KdV) equation with a fifth-order dispersion term,the perturbed fourth-order KdV equation,the KdV-Burgers equation,and a Boussinesq-type equation.