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．     

The multicomponent （2＋1）-dimensional Glachette-Johnson （GJ） equation hierarchy and its super-integrable coupling system

This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra A^-M. By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which possesses the Hamiltonian structure. As its reduction cases, the multicomponent （2＋1）-dimensional Glachette-Johnson （G J） hierarchy is given. Finally, the super-integrable coupling system of multicomponent （2＋1）-dimensional GJ hierarchy is established through enlarging the spectral problem.     

A new variable coefficient algebraic method and non-travelling wave solutions of nonlinear equations

In this paper, a new auxiliary equation method is presented of constructing more new non-travelling wave solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than projective Riccati equation method. In order to illustrate the validity and the advantages of the method, （2＋1）-dimensional asymmetric Nizhnik-Novikov-Vesselov equation is employed and many new double periodic non-travelling wave solutions are obtained. This algorithm can also be applied to other nonlinear differential equations.     

新的耦合mKdV方程族及其Liouville可积的无限维Hamilton结构

根据第Ⅱ屠格式,从一个特征值问题出发,本文推得了一族新的耦合ｍＫｄＶ方程,然后用迹恒等式人出了其无限维Ｈａｍｉｌｔｏｎ结构。最后证明了该Ｈａｍｉｌｔｏｎ方程族是Ｌｉｏｕｖｉｌｌｅ可积的,并且有无穷多个彼此对合的公共守恒密度。     

一个非线性方程的显示行波解

利用双曲函数法和吴元代数消元法,获得了Ｒ－Ｌ－Ｗ方程的多组行波解,其中包括新的行波解、有理函数形式的行波解。     

含外力项的广义KdV方程的新自Darboux变换和显式解析解

基于 Ｒｉｃｃａｔｉ形式的 Ｌａｘ对,本文推得了含外力项的广义 ＫｄＶ方程的新自Ｄａｒｂｏｕｘ变换．当应用这个变换时,仅需要做积分,就能获得一系列显示解析解,其中包含类孤波解．这种途径对于寻找非线性发展方程新的具有物理意义的解或许是有用的．     

Benjamin方程的Baecklund变换、非线性叠加公式及无穷守恒律

利用屠格式求出了Benjamin方程的Baecklund变换、精确孤波解、非线性叠加公式及其无穷守恒律,这种算法具有普适性。     

NEW EXPLICIT AND EXACT TRAVELLING WAVE SOLUTIONS FOR A COMPOUND KdV－BURGERS EQUATION

In this paper, new explicit and exact travelling wave solutions for a compound KdV－Burgers equation are obtained by using the hyperbola function method and the Wu elimination method, which include new solitary wave solutions and periodic solutions. Particularly important cases of the equation, such as the compound KdV, mKdV－Burgers and mKdV equations can be solved by this method. The method can also solve other nonlinear partial differential equations.     

拟协调元空间的紧致性和拟协调元法的收敛性

本文首先讨论拟协调元空间的紧致性,把Rellich紧致定理推广到拟协调元空间序列,进而把广义Poincare、Friedrichs和Poincare-Friedrichs等不等式推广到拟协调元空间.然后讨论拟协调元法的收敛性和误差估计.本文证明了如果拟协调元空间具有逼近性和强连续性、满足单元秩条件且通过检验IPT,则近似解是收敛的.做为例子,我们证明了6参、9参、12参、15参、18参及21参拟协调元的收敛精度在L2,2(Ω)范数下分别是O(h_τ)、O(h_τ)、O(h_τ2)、O(h_τ2)、O(h_τ3)及O(h_τ4)量级.     

非线性耦合标量场方程显式解析解的研究

利用两种不同的变换,获得了一类非线性耦合标量场方程的若干类型的精确解析解,其中包括孤子解、奇性孤波解和三角函数解,从而丰富了方程解的内容。这些结论可以应用于其它的非线性方程。此外还纠正了一些文献的部分结论。