B?cklund变换与n孤子解

本文首先证明了KdV方程与sine-Gordon方程不同形式的B?cklund变换是相互等价的;其次从双线性导数形式的B?cklund变换出发给出多孤子解的Hirota表示与Wronski行列式表示,并利用Vandermonde行列式说明这两种孤子解的表示是一致的.     

B(a)cklund变换与n孤子解

本文首先证明了KdV方程与sine-Gordon方程不同形式的B(a)cklund变换是相互等价的;其次从双线性导数形式的B(a)cklund变换出发给出多孤子解的Hirota表示与Wronski行列式表示,并利用Vandermonde行列式说明这两种孤子解的表示是一致的.     

正弦-Gordon方程n孤子解的一致性

正弦-Gordon方程是一种重要的非线性波动方程,其n孤子解具有Hirota表示与Wronski行列式表示形式,利用行列式的性质说明正弦-Gordon方程的这两种n孤子解的表示是一致的.     

mKdV-SineGordon方程的多孤子解

该文首先给出了mKdV-SineGordon方程的双线性形式和双线性Backlund变换,然后利用Hirota方法、Backlund变换方法和Wronskian技巧三种不同的方法分别得到mKdV-SineGordon方程的孤子解,最后验证了这三种解的一致性。     

广义耦合KdV孤子方程的达布变换及其奇孤子解

借助谱问题的规范变换, 给出广义耦合KdV孤子方程的达布变换,利用达布变换来产生广义耦合KdV孤子方程的奇孤子解,并且用行列式的形式来表达广义耦合KdV孤子方程的奇孤子解．作为应用,广义耦合KdV孤子方程奇孤子解的前两个例子被给出．     

广义耦合KdV孤子方程的达布变换及其偶孤子解

根据广义耦合KdV孤子方程的Lax对, 借助谱问题的规范变换, 一个包含多参数的达布变换被构造出来. 利用达布变换来产生广义耦合KdV孤子方程的偶孤子解, 并且用行列式的形式来表达广义耦合KdV孤子方程的偶孤子解. 作为应用, 广义耦合KdV孤子方程的偶孤子解的前两个例子被给出.     

基于Bell多项式的一类(3+1)维变系数广义浅水波方程的可积性研究

本文基于Bell多项式研究了一类(3+1)维变系数广义浅水波方程的可积性问题.首先,引入变量变换,借助Bell多项式与Hirota双线性算子之间的关系,导出方程的Hirota双线性形式,求出方程的N-孤子解,并对单孤子、双孤子和三孤子在不同情形下的传播进行图像模拟;其次,基于双线性方程,结合Bell多项式获得方程的双线性B?cklund变换;然后,通过Hopf-Cole变换,将双线性Backlund变换线性化,求出方程的Lax对;最后,利用级数展开法得到方程的无穷守恒律.从而证明该方程具有可积性.     

一个离散晶格方程的N波Darboux变换和无穷守恒律

根据已知离散晶格方程的Lax对,构建了该方程的Ⅳ波Darboux变换和无穷守恒律,通过应用Darboux变换,得到离散晶格方程的范德蒙行列式形式的精确解,通过画图给出了该方程一类特殊的单孤子结构.     

散焦mKdV方程的N重暗孤子解的行列式表示

该文首先构造了耦合的mKdV方程的新的达布变换,同时显式给出了它的达布矩阵T_N和新解q~([N]),r~([N])的行列式表示.其次,考虑将约化条件r=q*附加到该达布变换上,以及考虑一个周期的非零种子解,得到了散焦mKdV方程的N重暗孤子解的行列式表示.最后,证明了暗的单孤子解和暗的2孤子解是光滑的,进一步证明了暗的N(N≥2)孤子解至少在某一邻域内是光滑的.     

一类动力学中非线性偏微分方程解的研究与分析

通过Ibragimov新守恒定理的基本思想,构造了动力学Drinfel’d-Sokolov-Wilson(DSW)方程的局部守恒定律.并且利用Hirota双线性形式推导出该方程的双线性Backlund变换,在双线性Backlund变换的基础上,获得该方程的行波解.然后构造DSW方程的正四次函数、二次函数及指数函数所组合的形式解,另外构造了正四次函数、二次函数、三角函数和双曲函数组合的形式解,通过计算求解出DSW方程相应的高阶Lump解与Kink解、高阶Lump解与周期波解的相互作用解,同时验证了该方程解的存在性.     

VISCOSITY METHOD OF A NON－HOMOGENEOUS BURGERS EQUATION

Abstract In [1], Ding et al. studied the nonhomogeneous Burgers equation ut uux = μuxx 4x.(1.1) This paper will prove that when μ → 0 the solution of (1.1) will approach the generalized solution of ut uux = 4x.(1.2) The authors notice that the equation (1.2) is beyond the scope of investigations by Oleinik O. in [2]. The solutions here are unbounded in general. The paper also studies the δ-wave phenomenon when (1.2) is jointed with some other equation.     

REMARK ON UNIQUE CONTINUATION OF SOLUTIONS TO THE STOKES AND THE NAVIER-STOKES EQUATIONS

1IntroductionUnique continuation of solutions to the linear partial di?erential equations with analyticcoe?cients is well known.There are more general results in elliptic,parabolic and hyperbolicequations(cf.[8-10,12-13]and references therein).The continu…     

On reflection principles supported on a finite set

We investigate the existence of reflection formulas supported on a finite set. It is found that for solutions of the Laplace and Helmholtz equation there are no finitely supported reflection principles unless the support is a single point. This confirms that in order to construct a reflection formula that is not ‘point to point’, it is necessary to consider a continuous support. For solutions of the wave equation ^∂2u/∂x∂y=0, there exist finitely supported reflection principles that can be constructed explicitly. For solutions of the telegraph equation ^∂2u/∂x∂y+λ²u=0, we show that if a reflection principle is supported on less than five points then it is a point to point reflection principle.     

Approximate Solution of the Kuramoto-Shivashinsky Equation on an Unbounded Domain

The main goal of this paper is to approximate the Kuramoto-Shivashinsky (K-S for short) equation on an unbounded domain near a change of bifurcation, where a band of dominant pattern is changing stability. This leads to a slow modulation of the dominant pattern. Here we consider PDEs with quadratic nonlinearities and derive rigorously the modulation equation, which is called the Ginzburg-Landau (G-L for short) equation, for the amplitudes of the dominating modes.     

The variational iteration method for analytic treatment for linear and nonlinear ODEs

In this work, the variational iteration method (VIM) is used for analytic treatment of the linear and nonlinear ordinary differential equations, homogeneous or inhomogeneous. The method is capable of reducing the size of calculations and handles both linear and nonlinear equations, homogeneous or inhomogeneous, in a direct manner. However, for concrete problems, a huge number of iterations are needed for a reasonable level of accuracy.     

Analysis of a Diagonal Form of the Fast Multipole Algorithm for Scattering Theory

Discretisation of the integral equations of acoustic scattering yields a system of linear equations with full coefficient matrices. In recent years a number of fast algorithms for the solution of this system have been proposed. In this paper we present a complete analysis for a fast multipole method for the Helmholtz equation. A one-level diagonal form of the multipole method is applied to a hypersingular integral equation arising from 2d scattering theory. The error of the approximation is analysed and the results used to establish the complexity of the method.     

Global solvability for the Kirchhoff equations in exterior domains of dimension larger than three

We consider the unique global solvability of initial (boundary) value problem for the Kirchhoff equations in exterior domains or in the whole Euclidean space for dimension larger than three. The following sufficient condition is known: initial data is sufficiently small in some weighted Sobolev spaces for the whole space case; the generalized Fourier transform of the initial data is sufficiently small in some weighted Sobolev spaces for the exterior domain case. The purpose of this paper is to give sufficient conditions on the usual Sobolev norm of the initial data, by showing that the global solvability for this equation follows from a time decay estimate of the solution of the linear wave equation. Copyright © 2004 John Wiley & Sons, Ltd.     

New Bounds for the Inhomogenous Burgers and the Kuramoto-Sivashinsky Equations

We give a substantially simplified proof of the near-optimal estimate on the Kuramoto-Sivashinsky equation from a previous paper of the third author, at the same time slightly improving the result. That result relied on two ingredients: a regularity estimate for capillary Burgers and an a novel priori estimate for the inhomogeneous inviscid Burgers equation, which works out that in many ways the conservative transport nonlinearity acts as a coercive term. It is the proof of the second ingredient that we substantially simplify by proving a modified Kármán-Howarth-Monin identity for solutions of the inhomogeneous inviscid Burgers equation. We show that this provides a new interpretation of recent results obtained by Golse and Perthame.     

Oscillation and Nonoscillation Criteria for a Second Order Linear Equation

New oscillation and nonoscillation criteria are established for the equation