2+1-维变系数广义Kadomtsev-Petviashvili方程的相似约化

借助于MATHEMATICA软件,将直接约化法推广并应用到2+1-维变系数广义Kadomtsev-Petviashvili(VCGKP)方程,获得了VCGKP方程的若干相似约化,其中包括PainleveⅠ型、PainleveⅡ型和PainleveⅣ型的约化.     

Similarity Solutions of a Generalized Burgers Equation

The similarity method is applied to a generalized Burgers equationwhich has been applied to shock waves and to sound waves. Threedifferent cases of the equation, each allowing a three-parametersymmetry group, are found. The corresponding reduction to anordinary differential equation is given. The Lie algebras ofthe groups are identified with standard types given by Bianchi.     

二类变式Boussinesq方程的对称性约化和精确解

将Ｃｌａｒｋｓｏｎ等最近发展的直接法推广应用于变式Ｂｏｕｓｓｉｎｅｓｑ方程组,给出四种类型对称性约化方程和三组显式精确解．结果表明：在适当变换下变式Ｂｏｕｓｓｉｎｅｓｑ方程组可约化为具有椭圆函数解的Ｄｕｆｆｉｎｇ型方程和Ｐａｉｎｌｅｖ　Ⅱ方程,并且约化结果包含有关于时间ｔ的二种类型奇点;极点和代数支点．     

源于Fermi-Pasta-Ulam问题的非线性发展方程的相似约化

利用Clarkson和Kruskal引入的直接法和Lou的改进的直接法,给出了源于Fermi-Pasta-Ulam问题的非线性发展方程的4种类型的相似约化.     

（２＋１）维非线性色散长波方程的相似约化和解析解

首先借助于Ｍａｔｈｅｍａｔｉｃａ软件,将Ｃｌａｒｋｓｏｎ和Ｋｒｕｓｋａｌ引入的直接约化法推广并应用于（２＋１） 维偏微分方程组情形 （２＋１） 维非线性色散长波方程,获得了该方程的六种类型的相似约化和若干解析解,其中包括ＰａｉｎｌｅｖｅⅡ型方程和孤子解．然后基于文［５］的结论,通过引入新的级数变换,获得了该方程的有理分式解析解．这种方法也适合于其它的微分方程．     

Similarity Solutions of a Non-linear Diffusion Equation

In several physical contexts the equations for the dispersionof a buoyant contaminant can be approximated by the Erdogan-Chatwin(1967) equation {dot}c = {dot}_y{[D_o + ({dot}_yc)²D₂]{dot}_yc}. Here it is shown that in the limit of strong non-linearity (i.e.D_o = 0) there are similarity solutions for a concentration jumpand for a finite discharge. A stability analysis for the latterproblem involves a new family of orthogonal polynomials Y_n(z)where (1 – z⁴)Y – 6z³Y + n(n + 5)z² Y_n = 0 and the degree n is restricted to the values 0, 1, 4, 5, 8,9,.... A numerical solution of the Erdogan-Chatwin equationis given which describes the transition between the non-linearand linear (Gaussian) similarity solutions.     

Quantitative Stability of a Generalized Equation

The paper is devoted to the study of several stability properties (such as Aubin/Lipschitz-like property, calmness and isolated calmness) of a special non-monotone generalized equation. The theoretical results are applied in the theory of non-regular electrical circuits involving electronic devices like ideal diode, practical diode, and diode alternating current.     

Symmetry Reductions of the Combined KdV—mKdV Equation

ＳｙｍｍｅｔｒｙＲｅｄｕｃｔｉｏｎｓｏｆｔｈｅＣｏｍｂｉｎｅｄＫｄＶ－ｍＫｄＶＥｑｕａｔｉｏｎＺｈａｎｇＪｉｅｆａｎｇ（张解放）；ＸｕＸｕｅｊｕｎ（许学军）；ＣｈｅｎｇＤｅｓｈｅｎｇ（程德声）（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，Ｚｈｅｊｉａｎｇ...     

Generalized CR Equation with a Singularity

This article deals with the solvability of the CR equation rw = (A₀(θ) ? O(r^α))w ? (B₀(θ) ? O(r^α)), where z = r e^iθ and where A₀, B₀ are continuous and 2π-periodic. The solutions of this equation are shown to be similar to those of the model equation rw = A₀(θ)w ? B₀(θ). The solutions of the model equation are completely characterized by using dynamical systems and Fourier techniques.     

关于广义 Bernoulli 方程的注记

针对广义Bernoulli方程的可积性给出几点注记,并在已有结果的基础上,做进一步研究和推广.     

广义KdV方程与广义Burgers方程的精确解

利用试探函数法和直接积分法构造广义KdV方程与广义Burgers方程的新的精确解.     

一类广义Tjon-Wu方程的渐近稳定性

研究Boltzmann方程的一个动力学模型:Tjon-Wu方程的更一般的形式.我们证明了在L_(1.1)范数意义下方程的稳态解的渐近稳定性.     

一维广义Ginzburg－Landau方程的指数吸引子

本文在[1]的基础上,得到了一维广义Ginzburg-Landau方程的指数吸引子的存在性。     

Kinetic Equation for Soliton Gas: Integrable Reductions

We study the dynamic behaviour of two viscous fluid films confined between two concentric cylinders rotating at a small relative velocity. It is assumed that the fluids are immiscible and that the volume of the outer fluid film is large compared to the volume of the inner one. Moreover, while the outer fluid is considered to have constant viscosity, the rheological behaviour of the inner thin film is determined by a strain-dependent power-law. Starting from a Navier–Stokes system, we formally derive evolution equations for the interface separating the two fluids. Two competing effects drive the dynamics of the interface, namely the surface tension and the shear stresses induced by the rotation of the cylinders. When the two effects are comparable, the solutions behave, for large times, as in the Newtonian regime. We also study the regime in which the surface tension effects dominate the stresses induced by the rotation of the cylinders. In this case, we prove local existence of positive weak solutions both for shear-thinning and shear-thickening fluids. In the latter case, we show that interfaces which are initially close to a circle converge to a circle in finite time and keep that shape for later times.

     

一类Fisher方程的行波解

本文讨论了一类广义Fisher方程,得到了它的多个显式行波解.     

一类广义Boussinesq方程的Wronskian行列式解

为了构造非线性孤子方程的Wronskian行列式新解,进一步研究了Wronskian技巧.本文首先给出非线性广义Boussinesq方程的双线性形式,利用Wronskian技巧构造出该非线性方程所满足的一个线性偏微分条件方程组,然后求解该微分条件方程组,得到了广义Boussinesq方程的各种Wronskian行列式解.     

Sensitivity of Solutions to a Parametric Generalized Equation

In the present paper we prove that, under some suitable conditions on multifunctions $C\!: {I\!\!R}^l\rightrightarrows {I\!\!R}^n$ , $F\!:{I\!\!R}^d\times {I\!\!R}^n\rightrightarrows {I\!\!R}^m$ , and $K\!:{I\!\!R}^l\times {I\!\!R}^n\rightrightarrows {I\!\!R}^m$ , the generalized perturbation multifunction $G\!: {I\!\!R}^d\times{I\!\!R}^l\times {I\!\!R}^m\rightrightarrows {I\!\!R}^n$ , of the form $$G(\mu,\lambda,\nu)=\{x\in C(\lambda)\ |\ \nu\in F(\mu,x)+K(\lambda,x)\},$$ is proto-differentiable at (μ, λ, ν) relative to x?∈?G(μ, λ, ν). Moreover, in a special case, where K(λ, x) is a normal cone to C(λ) at x, we also provide sufficient conditions for G(·) to be single-valued on a neighborhood of (μ, λ, ν) and semi-differentiable at (μ, λ, ν).     

Cauchy Problem for a Generalized Nonlinear Dispersive Equation

The solvability of global smooth solution for the Cauchy problem of a generalized nonlinear dispersive equation is studied by using the continuation method. In addition, the convergences of solution for this problem are also discussed.     

关于广义Ramanujan-Nagell方程的一个猜想

设D=3a^2＋1，P=4a^2＋1是奇素数，其中a是正整数．本文证明了：当a〉6．10^18时，方程x^2＋D^m=P^n恰有2组正整数解（x，m，n）=（a，1，1）和（8a^3＋3a，1，3）．