一类五阶非线性波方程的新精确解

通过利用新的G展开法,并借助Mathematica计算软件,研究了一类五阶非线性波方程的精确解,获得了方程的含有多个任意参数的新的显式行波解,分别为三角函数解、双曲函数解、指数函数解,扩大了该类方程的解的范围.     

一类推广的KdV方程的新行波解

本文研究了一类推广的Kd V方程的行波解求解的问题.利用新的G展开法,并借助Mathematica计算软件,获得了该方程的含有多个任意参数的新的行波解,分别为三角函数解、双曲函数解、有理函数解和指数函数解,扩大了该类方程的解的范围.     

Davey-Stewartson方程新的周期孤立波解

首先介绍了Davey-Stewartson方程、Darboux算子和Lax对的概念,然后利用Darboux变换结合Lax对的方法对Davey-Stewartson方程求解,得到了DSII方程新的周期孤立波解,DSI方程新的双周期解.     

高阶Camassa—Holm方程的一类行波解

研究高阶Camassa-Holm方程的行波解,采用一种新的方法求解行波方程,获得了高阶Camassa-Holm方程的一类行波解．     

一类非线性发展方程的显式精确解

提出了寻求非线性发展方程行波解新的辅助方程法,作为实例通过选取变系数Bernoulli方程作为辅助常微分方程,并借助于计算机系统Mathematica和齐次平衡原则,求解了一类非线性发展方程,得到了该方程的新的显式精确解.所用方法可应用到其它类似方程的求解.     

（2＋1）维KP方程的三类精确解

研究了（2＋1）维KP方程的孤子解问题．应用Riccati方程映射法,得到了（2＋1）维KP方程的新的显式精确解的结构．根据得到的精确解结构,构造出了该方程的三类精确解．     

(2+1)维浅水波方程的新精确解

对(2+1)维浅水波方程的现有解进行了推广.应用CK方法对方程进行求解,得到方程的Backlund变换公式,将已知解代入公式,求得一些新的精确解,从而推广了浅水渡方程的解.     

耦合KdV方程的几个精确解

Darboux变换是求孤子方程的精确解的一种新方法。它借助于孤子方程的Lax对。从方程的平凡解导出新的非平凡解。本文对一个四阶特征值问题找出了Darboux变换,并由此得到耦合KdV方程的孤子解,周期解,极点解等。     

一类具多偏差变元的p-Laplacian方程周期解的存在性

研究了一类具多偏差变元的p-Laplacian方程,为了得到该方程周期解的先验估计,运用分析技巧建立了一些新的不等式,进而利用Mawhin连续定理得到了这类方程周期解的存在性,得到了一些新的结果,推广和改进了已有结果.     

一类具有波动算子非线性Schrdinger方程的新多级包络周期解北大核心CSCD

该文给出了求解具有波动算子的非线性Schrdinger方程包络周期解的一种新方法.首先在构建的微分动力系统中分析了其平衡解的特性,其次通过将Lam方程及新的Lam函数与Jacobi椭圆函数展开法进行结合的办法得到了新的多级包络周期解,最后在极限条件下获得该方程相应的新包络孤波解以及其他形式的解.     

Rarefaction Wave Interaction and Shock-Rarefaction Composite Wave Interaction for a Two-Dimensional Nonlinear Wave System

In order to construct global solutions to two-dimensional(2 D for short)Riemann problems for nonlinear hyperbolic systems of conservation laws,it is important to study various types of wave interactions.This paper deals with two types of wave interactions for a 2 D nonlinear wave system with a nonconvex equation of state:Rarefaction wave interaction and shock-rarefaction composite wave interaction.In order to construct solutions to these wave interactions,the authors consider two types of Goursat problems,including standard Goursat problem and discontinuous Goursat problem,for a 2 D selfsimilar nonlinear wave system.Global classical solutions to these Goursat problems are obtained by the method of characteristics.The solutions constructed in the paper may be used as building blocks of solutions of 2 D Riemann problems.     

Wave Instabilities

A uniform train of periodic waves may be unstable to large scale variations so that some incoherence can develop. The analysis is presented for the case of gravity waves, and for a class of interaction problems typical of many physical systems.     

强非线性波动方程孤子行波解

研究了一个强非线性波动方程.利用泛函分析变分迭代方法，首先构造了一个变分, 求出相应的Lagrange乘子；其次构造一个解的变分迭代, 选取初始孤子波；最后利用迭代方法依次求出各次孤子波的近似解.该方法是一个简单可行的近似求解非线性方程的方法     

Nonlinear Amplitude Evolution of Baroclinic Wave Trains and Wave Packets

The weakly nonlinear theory of baroclinic wave trains and wave packets is examined by the use of systematic expansion procedures in appropriate powers of a small parameter measuring the supercriticality according to linear theory; well-known multiple scaling techniques are employed. Crucial importance is ascribed to the magnitude of parameters measuring dissipation and dispersion relative to each other and to the supercriticality, and equations describing the slow evolution in space and time of the wave amplitude are established for a range of parameter values. For vanishingly small dissipation the wave train equations have straightforward oscillatory solutions, dependent on initial conditions, and for large dissipation steady equilibration, independent of initial conditions, is predicted. For moderately small dissipation, however, a wide variety of behaviors is possible—including steady equilibration, single and multiple periodicity, and aperiodicity—in the solutions of the equations, which are recognizable as generalisations of the well-known Lorenz attractor equations. Equations describing the evolution of wave packets take a variety of forms; for vanishingly small dissipation or for large dissipation, they are essentially parabolic and of nonlinear Schrödinger type, whilst for moderate dissipation they are of Lorenz type, modified by spatial variations. Solutions of a number of these equations are discussed and compared, where appropriate, with experimental results.     

Compressive Wave Computation

This paper presents a method for computing the solution to the time-dependent wave equation from the knowledge of a largely incomplete set of eigenfunctions of the Helmholtz operator, chosen at random. While a linear superposition of eigenfunctions can fail to properly synthesize the solution if a single term is missing, it is shown that solving a sparsity-promoting ℓ ₁ minimization problem can vastly enhance the quality of recovery. This phenomenon may be seen as “compressive sampling in the Helmholtz domain.”     

对称正则长波方程的行波解分岔

通过平面动力系统的方法讨论了对称正则长波方程的分岔问题.得到了该方程的分岔条件,在一些参数的具体值的情况下给出相图并通过微分方程的数值模拟方法模拟出了该方程的周期行波解、孤立行波解及无界行波解.     

外界场作用下的波前曲率关系和波形变化

研究外界场作用下,激发介质的波前曲率关系和波形变化·　理论分析波前曲率关系,得到外界场作用下,波前的法向速度与波前平均曲率、平面波速和外界场之间的线性关系·　数值分析外界场作用下,激发介质的Bar_Eiswirth模型,得到外界场作用下激发介质的波形图案·　这里的理论分析、数值结果与BZ反应的实验结果完全一致,从而解释了外界场作用下的BZ现象,且由数值结果可知激发介质包含丰富的波形图案·     

Random Wave Closures

A detailed study is made of the way in which weak nonlinearities affect the statistical properties of a system of dispersive waves. Given that at some initial instant the spectral cumulants are sufficiently smooth it is shown that they will remain smooth to zeroth order, save in one dimension where a discrete spectrum may eventually be generated. Of prime interest is the fact that on considering the long time behavior of the system, one is led to a sequence of closures for the zeroth order spectral functions. Apparent difficulties associated with the irretraceability of the solution are discussed. The structure of the closure equations depends on the asymptotic behavior of a class of singular integrals.     

Wave recursive interpolation

In this paper it is studied that the generated theory of wave recursive interpolation of uniform T-subdivi-ston scheme include wave parameter.The paper analyses the convergence of sequences of control polygons produced by wave recursive interpolation T-subdivision scheme of the formj=l,2,…,T-1;m=O,l,…,nTk;k=0,l,2,…,and differentiability of the limit curve.     

Exact Solitary Wave And Periodic Wave Solutions Of The Kaup-Kuperschmidt Equation

In this paper we investigate the exact traveling wave solutions of the fifth-order Kaup-Kuperschmidt equation. The bifurcation and exact solutions of a general first-order nonlinear equation are investigated firstly. With the help of Maple and by using the bifurcation and exact solutions of two derived subequations, we obtain two families of solitary wave solutions and two families of periodic wave solutions of the KK equation. The relationship of the two subequations and the two known rst integrals are analyzed.