一类非线性波方程尖波解及其动力学性质的分析

应用动力系统分岔理论和定性理论研究了一类非线性DegasperisProcesi方程的行波解及其动力学性质,并结合可积系统的特点,利用哈密尔顿系统的能量特征,通过Maple软件绘出其相轨图,再根据行波与相轨道间的对应关系,揭示了不同类型的行波解间的转变与参数变化的关系,并且给出了不同行波间相互转换的参数分岔值,从根本上解释了Peakon产生的原因.数值模拟验证了该方法的正确性.最后给出了相应行波解的表达式.     

非线性演化方程的新Jacobi椭圆函数解

基于sinh-Gordon方程的椭圆函数解,构造新的试探解来扩展sinh-Gordon方程展开法.利用该方法研究了KdV-mKdV方程,双sine-Gordon方程和BBM方程,获得了这些方程的新Jacobi椭圆函数解.该方法也能用来求解其他数学物理中的非线性演化方程.     

求一类非线性偏微分方程解析解的简洁构造算法

通过引入一个变换,利用齐次平衡原理和选准一个待定函数来构造求解一类非线性偏微分方程解析解的算法.作为实例,我们将该算法应用到了mKdV方程,KdV-Burgers方程和KdV-Burgers-Kuramoto方程.借助符号计算软件Mathematica获得了这些方程的解析解.不难看出,该方法不仅简洁,而且有望进一步扩展.     

(3+1)维修正KdV-Zakharov-Kuznetsov方程的行波解

结合动力系统分支理论,对一个非线性(3+1)维修正KdV-Zakharov-Kuznetsov方程进行理论上的研究.首先,根据不同参数值和三次方程判别式分别定性分析了平衡点的类型和相应轨线情况.其次,利用Ja-cobi椭圆函数,从形式上给出了若干有界行波解和同宿轨的公式,这一结论扩展了已有文献的工作.最后,利用Hami...     

长短波相互作用方程组的无穷序列新解

本文对长短波相互作用方程组作行波变换后转化成第一种椭圆方程,利用第一种椭圆方程的解和Bcklund变换,构造了长短波相互作用方程组的无穷序列新解.这里包括了椭圆函数解、双曲函数解、指数函数解和有理函数解.     

(2+1)维Bogoyavlenskii-Schiff方程的精确解

应用简单方程法求得(2+1)维Bogoyavlenskii-Schiff方程的精确解,这种方法对于研究非线性发展方程具有非常广泛的应用意义.     

Burgers方程的精确解

引入一个变换,将二阶非线性偏微分方程—Burgers方程降阶为一阶的非线性方程,再直接求解该方程,得出了Burgers方程精确解的新形式,并与已有结果完全吻合.这种方法也适合于求解其他非线性偏微分方程.     

对称正则长水波方程的畸形波解（英文）

众所周知,非线性发展方程在准确描述自然现象方面起着很重要的作用。我们已经应用许多方法获得了孤子解和周期波解。本论文中,将发现非线性发展方程的一种叫做畸形波解的新类型的解,同时也提出了寻求方程畸形波解的一种新的方法 HBLM。(1+1)维对称正则长水波方程(SRLW)作为本文的案例,强调了所提方法的有效性。     

(2+1)维KD方程的解及分岔行为

通过行波变换,将非线性偏微分方程化为常微分方程,利用辅助常微分方程的解来构造偏微分方程的精确解,获得了(2+1)维Konopelchenko-Dubrovsky方程的孤波解和周期解.然后直接研究变换以后的常微分方程,揭示该方程控制的动力系统的鞍结分岔行为,画出了系统的分岔图.     

关于一般耦合矩阵方程的迭代对称解

本文构造了一个有效的迭代方法(CGL)去求解一般耦合矩阵方程的对称解.若一般耦合矩阵方程关于对称解相容,则对于任意给定的初始对称矩阵组,利用所构造的迭代算法,都能在有限步迭代出所求问题的一组对称解,若选用一些特殊的初值,则可获得矩阵方程的极小范数对称解.最后的数值例子表明了所给算法的有效性.     

Simplest equation method for some time-fractional partial differential equations with conformable derivative

The conformable fractional derivative was proposed by R. Khalil et al. in 2014, which is natural and obeys the Leibniz rule and chain rule. Based on the properties, a class of time-fractional partial differential equations can be reduced into ODEs using traveling wave transformation. Then the simplest equation method is applied to find exact solutions of some time-fractional partial differential equations. The exact solutions (solitary wave solutions, periodic function solutions, rational function solutions) of time-fractional generalized Burgers equation, time-fractional generalized KdV equation, time-fractional generalized Sharma–Tasso–Olver (FSTO) equation and time-fractional fifth-order KdV equation, $(3+1)$-dimensional time-fractional KdV–Zakharov–Kuznetsov (KdV–ZK) equation are constructed. This method presents a wide applicability to solve some nonlinear time-fractional differential equations with conformable derivative.     

New generalized method to construct new non-travelling wave solutions and travelling wave solutions of K–D equations

With the aid of computerized symbolic computation, we obtain new types of general solution of a first-order nonlinear ordinary differential equation with six degrees of freedom and devise a new generalized method and its algorithm, which can be used to construct more new exact solutions of general nonlinear differential equations. The (2+1)-dimensional K–D equation is chosen to illustrate our algorithm such that more families of new exact solutions are obtained, which contain non-travelling wave solutions and travelling wave solutions.     

Solitary wave solutions of (3+1)-dimensional extended Zakharov–Kuznetsov equation by Lie symmetry approach

In this paper, the solitary wave solutions of (3+1)-dimensional extended Zakharov–Kuznetsov (eZK) equation are constructed which appear in the magnetized two-ion-temperature dusty plasma and quantum physics. Lie group of transformation method is proposed to investigate the solution of (3+1)-dimensional eZK equation via Lie symmetry method. The optimal system of one dimensional Lie subalgebra is constructed by using Lie point symmetries. The three dimensional eZK equation reduced into number of ordinary differential equations (ODEs) by applying similarity reductions. Consequently, solutions so extracted are more general than erstwhile known results. We have obtained twenty one solutions in the explicit form, some of them are likewise general and some are new for the best study of us. Eventually, single soliton, quasi-periodic soliton, multisoliton, lump-type soliton, traveling wave and solitary wave-interaction behavior are illustrated graphically through numerical simulation for physical affirmation of the results. Please check whether the affiliations are correct.     

求解非线性悬梁方程行波解的变分算法Mountain Pass算法

§１．引言 经典的求解微分方程初一边值问题的算法，无不要求我们事先对解的某些性质有所了解．例如利用Ｒｕｎｇｅ－Ｋｕｔｔａ法解四阶常微分方程，我们至少需要知道解及其１—３阶导数的初值；又如广义牛顿法则对于初始点的选取有较高的要求，等等．如果事先对所求之解没有足够的了解，就给求解一般（特别是非线性）问题带来困难． １９７３年由 Ａｍｂｒｏｓｅｔｔｉ和 Ｒａｂｉｎｏｗｉｔｚ提出的 Ｍｏｕｎｔａｉｎ Ｐａｓｓ理论（一译“爬山理论”，又译“山径理论”）现己发展成为讨论非线性泛函临界值问题的一个重要方法之一．其几…     

Comment on “A direct approach with computerized symbolic computation for finding a series of traveling waves to nonlinear equations” by Engui Fan and H.H. Dai: [Comput. Phys. Commun. 153 (2003) 17]

Fan and Dai [Comput. Phys. Commun. 153 (2003) 17] have found a series of traveling wave solutions for nonlinear equations by applying a direct approach with computerized symbolic computations. They have claimed that the proposed method, in comparison with most existing symbolic computation methods such as a tanh method and Jacobi function method, not only give new and more general solutions, but also provides a guideline to classify various types of the solution according to some parameters. We show that the claims by Fan and Dai are wrong since some of the solutions do not satisfy the differential equation that they have adopted for the algebraic method.     

位移法浅水波方程的解及其特性

不同于传统流体力学,在Lagrange坐标下推导浅水波方程.若将水平位移作为基本变量,则推导出的浅水波数学模型可描述为固体力学的非线性大位移问题.运用不可压缩条件,通过变分原理推导出位移法浅水波方程,给出椭圆函数形式的行波解,并分析孤波解产生的条件.该基础研究建立了在分析结构力学中分析浅水波问题的理论基础,有利于进一步开展水动力学的研究.     

Towered waves and anti-waves in the generalized Degasperis-Procesi equation

New traveling wave solutions of the generalized Degasperis-Procesi equation are investigated. The solutions are characterized by three parameters. Using an improved qualitative method, abundant traveling wave solutions, such as smooth waves, peaked waves, cusped waves, compacted waves, looped waves and fractal-like waves, are obtained. Especially, some strange composite wave solutions such as towered waves and their anti-waves are first given. We also study the limiting behavior of all periodic solutions as the parameters trend to some special values.