New infinite-dimensional hidden symmetries for the stationary axisymmetric Einstein－Maxwell equations with multiple Abelian gauge fields

By proposing a so-called extended hyperbolic complex (EHC) function method, an Ernst-like (p+2)×(p+2) matrix EHC potential is introduced for the stationary axisymmetric (SAS) Einstein－Maxwell theory with p Abelian gauge fields (EM-p theory, for short), then the field equations of the SAS EM-p theory are written as a so-called Hauser－Ernst-like self-dual relation for the EHC matrix potential. Two Hauser－Ernst-type EHC linear systems are established, based on which some new parametrized symmetry transformations for the SAS EM-p theory are explicitly constructed. These hidden symmetries are found to constitute an infinite-dimensional Lie algebra, which is the semidirect product of the Kac－Moody algebra su(p+1,1)\otimes R(t,t^{-1}) and Virasoro algebra (without centre charges). All of the SAS EM-p theories for p=0,1,2,… are treated in a unified formulation, p=0 and p=1 correspond, respectively, to the vacuum gravity and the Einstein－Maxwell cases.     

New Exact Solutions of Broer-Kaup Equations

Based on a known transform, the exact solutions of (2 1)-dimensional Broer-Kaup equations are investigated by using the method of direct integral. A kind of new exact solutions of Broer Kaup equations are obtained,which contain previous results about solitary wave solutions.     

边界元技术中的全特解场方法

采用相应基本解来构造全特解场，据而确定各该问题边界元方程系数矩阵的全部元素。解算中不涉及具体插值，不用数值积分，避免了奇异积分的数值处理，而任意点的物理量计算（如应力、声强等等）不依赖于待解的边界未知量，因而算效奇高，精度特好。适于求解各类数学物理和工程技术问题。     

《数学物理方法》课程教改的探索与实践

随着我国科学技术的快速发展,对于理工科学生在数学基础和数学素养方面的要求越来越高.数学物理方法课程综合应用了各个数学分支的内容,是提升理工科本科学生应用数学能力的重要基础课程.本文以课程作用、课程安排以及教学内容的梳理改进为主线,介绍数学物理方法课程教改的思考与实践.     

All Meromorphic Solutions of Some Algebraic Differential Equations

In this article, we introduce some results with respect to the integrality and exact solutions of some 2nd order algebraic DEs. We obtain the sufficient and necessary conditions of integrable and the general meromorphic solutions of these equations by the complex method, which improves the corresponding results obtained by many authors. Our results show that the complex method provides a powerful mathematical tool for solving a large number of nonlinear partial differential equations in mathematical physics.     

Periodic solutions of nonlinear Schro^edinger type equations

By using the solutions of an auxiliary elliptic equation, a direct algebraic method is proposed to construct the exact solutions of nonlinear Schrfdinger type equations. It is shown that many exact periodic solutions of some nonlinear Schro^edinger type equations are explicitly obtained with the aid of symbolic computation, including corresponding envelope solitary and shock wave solutions.     

Solitary Wave Solutions of Triple Sine-Gordon Equation

Through a mapping relation between the triple sine-Gordon and Ф5 model, we discuss the equation in detail. A series of solitary wave solutions for the triple sine-Gordon equation is obtained by the existing ones of the Ф5 model. Some detailed solitary wave solutions are given for some special coefficients which have significance in physics.     

Partial regularity for weak solutions of stationary navier-stokes systems

This article is concerned with the partial regularity for the weak solutions of stationary Navier-Stokes system under the controllable growth condition.By A-harmonic approximation technique,the optimal regularity is obtained.     

Infinite-Parameter Potential Symmetries and a New Exact Solution for the Particle-Cluster Dynamic Equation

The master equation of a one-dimensional lattice-gas model with order preservation where the occupation probabilities of sites corresponding to Bose statistics as a consequence of the prescribed dynamics is studied with the potential symmetry method.The infinite-parameter potential symmetry and a new exact solution are obtained.The result illustrates that there remains the possibility of the above nonlinear equation to a linear partial differential equation by a non-invertible mapping.