非线性波方程准确孤立波解的符号计算

该文将机械化数学方法应用于偏微分方程领域，建立了构造一类非线性发展方程孤立波解的一种统一算法，并在计算机数学系统上加以实现，推导出了一批非线性发展方程的精确孤立波解．算法的基本原理是利用非线性发展方程孤立波解的局部性特点，将孤立波表示为双曲正切函数的多项式．从而将非线性发展方程（组）的求解问题转化为非线性代数方程组的求解问题．利用吴文俊消元法在计算机代数系统上求解非线性代数方程组，最终获得非线性发展方程（组）的准确孤立波解.  

Lukasiewicz n值命题逻辑中命题的真度理论

利用势为 n的均匀概率空间的无穷乘积在 Lukasiewicz n值命题逻辑中引入了公式的真度概念,当3≤n≤17时证明了全体公式的真度值之集在[0,1]上是稠密的,并给出了公式真度的表达通式;利用真度定义了公式间的相似度,进而导出了全体公式集上的一种伪距离,为n值Lukasiewicz命题逻辑系统的近似推理理论提供了一种可能的框架。  

解高维广义对称正则长波方程的Fourier谱方法

１引言对称正则长波方程（ＳＲＬＷＥ）是正则化长波方程（ＲＬＷＥ）的一种对称叙述［１］用于描述弱非线性作用下空间变换的离子声波传播．［１］得到了方程组（１．１）的双曲正割平方孤立波解、四个不变量和数值结果、明显地，从（１．１）中消去ρ，得到一类正则长波方程（ＲＬＷＥ）代替（１．２）中第三项、第四项对ｔ的导数为对ｘ的导数，得到Ｂｏｕｓｓｉｎｅｓｑ方程．［２］对一类广义对称正则长波方程组提出了谱方法，证明了古典光滑解的存在性和唯一性，建立了近似解的收敛性和误差估计。［３］研究了高维对称正则长波方程整体…  

A generalized variational principle and theoretical model for magnetoelastic interaction of ferromagnetic bodies

The quantitative analysis shows that no theoretical model for 3-d magnetoelastic bodies, in literatures to date, can commonly simulate two kinds of distinct experimental phenomena on magnetoelastic interaction of ferromagnetic structures. This makes it difficult to effectively discribe the magnetoelastic mechanical behavior of structures with complex geometry, such as shells. Therefore, it is a key step for simulating magnetoelastic mechanical characteristics of structures with complex geometry to establish a 3-d model which also can commonly characterize the two distinct experimental phenomena. A theoretical model for three dimension magnetizable elastic bodies, which is commonly suitable for the two kinds of experimental phenomena on magnetoelastic interaction of ferromagnetic plates, is presented by the variational principle for the total energy functional of the coupling system of the 3-d ferromagnetic bodies. It is found that for the case of linear isotropic magnetic materials, the magnetic forces obtained by this model include not only the body magnetic force which is the same as that got from the magnetic dipole model, but also a distribution of the magnetic traction on the surface of the magnetizable body. And the value of the traction is equal to the jumping one of the Faraday electromagnetic stress on the two sides of the surface, which does not appear in any model, such as magnetic dipole model and axiomatic model. Project supported by the National Natural Science Foundation of China( Grant No. 19572031), the National Science Fundation for Outstanding Young Scientiests in China, and a united foundation of the State Education Committee of China and National Natural Science Foundation Committee.  

Applications of F-expansion to periodic wave solutions for a new Hamiltonian amplitude equation

We present an extended F-expansion method for finding periodic wave solutions of nonlinear evolution equations in mathematical physics, which can be thought of as a concentration of extended Jacobi elliptic function expansion method proposed more recently. By using the F-expansion, without calculating Jacobi elliptic functions, we obtain simultaneously many periodic wave solutions expressed by various Jacobi elliptic functions for the new Hamiltonian amplitude equation introduced by Wadati et al. When the modulus m approaches to 1 and 0, then the hyperbolic function solutions (including the solitary wave solutions) and trigonometric function solutions are also given respectively. As the parameter ε goes to zero, the new Hamiltonian amplitude equation becomes the well-known nonlinear Schrödinger equation (NLS), and at least there are 37 kinds of solutions of NLS can be derived from the solutions of the new Hamiltonian amplitude equation.  

带梯度项的半线性椭圆与抛物型方程解的死核问题

带梯度项的半线性椭圆与抛物型方程解的死核问题程尚斌（兰州大学数学系，兰州７３００００）兰州大学科研基金资助课题．１９９１年３月１１日收到，１９９１年１１月２３日收到修改压缩稿．一、引言１９８４年，人们发现对一定类型的半线性椭圆与抛物型方程，它们具非零...  

On congruence lattices of regular semigroups with Q-inverse transversals

Communicated by F. Pastijn  

Global Attractors for a Nonclassical Diffusion Equation

We prove the existence of global attractors in H0^1 （Ω） for a nonclassical diffusion equation. Two types of nonlinearity f are considered： one is the critical exponent, and the other is the polynomial growth of arbitrary order.  

二阶半线性常微分方程的区间振动准则

通过利用平均函数及 Ｈａｒｄｙ ，Ｌｉｔｔｌｅｗｏｏｄ和 Ｐｏｌｙａ不等式，对二阶半线性微分方程建立了一些新的区间振动准则，这些准则不同于已知的依赖于整个区间[ｔ０，∞）的性质的结果，而是仅依赖于区间[ｔ０，∞）的子区间列的性质．所得结果推广和改进了 Ｋａｍｅｎｅｖ，Ｋｏｎｇ，Ｌｉ和 Ｙｅｈ及 Ｐｈｉｌｏｓ的振动准则，同时也可应用于以前所不能处理的某些情形，如特别，还给出了几个例子以说明本文所得结果优越性．  

Ekeland变分原理的推广及其应用

本文首先将Ekeland变分原理推广成一般的形式,然后考虑(P.S.)′条件与泛函的强制性之间的关系.