几类带双周期裂缝的无限平面弹性问题

本文讨论了基本周期胞腔内含一条任意形状光滑裂缝时的三类双周期平面弹性问题。本文采用复变方法求解,把寻求复应力函数的问题归结求解某种正则型奇异积分方程,证明了这种方程的解存在且唯一。     

带裂缝的双周期各向异性平面弹性基本问题

无限平而中带双周期分布裂缝的弹性基本问题,是有应用价值的重要课题。对于各向同性材料,这个问题业已解决,本文将讨论各向异性的情况。§1.复应力函数设无限各向异性弹性平面中有无限条双周期分布的裂缝,其周期为2w_1,2w_2,不     

带裂缝的双周期平面弹性基本问题

求解带裂缝的双周期平面弹性基本问题,是路见可教授提出的。本文将路见可在[4]中讨论裂缝问题的第五章所采用的方法加以推广,把寻求复应力函数的问题归结为求解某种类型的奇异积分方程讨论了这种方程的可解性,从而解决了带双周期裂缝的无限弹性平面的第一和第二基本问题。我们限于讨论基本周期胞腔内仅含一条任意形状裂缝的情况。基本胞腔内含若干条裂缝时,复应力函数一般是多值的,可先把多值部份分出,完全类似地不难解决这种一般情况下的第一和第二基本问题。     

三维各向同性不同材料带双周期孔洞的弹性焊接混合边值问题

本文利用复势方法讨论三维各向同性不同材料带双周期孔洞的弹性焊接混合边值问题,将三维应力系统分解为线性独立的两组二维应力系统,然后把复Airy函数法用于推广方法,将寻求复应力函数的问题归结为求解正则型的奇异积分方程,并证明了其解的存在唯一,由于所用方法是构造性的,故有利于数值计算。     

三维各同性不同材料带双周期孔洞的弹性焊接混合边值问题

本文利用复势方法讨论三维各同性不同材料带双周期孔洞的弹性焊接混合边值问题。将三维应用 力系统分解为线性独立的两组二维应力系统，然后把复Airy函数法用于推广ⅢepMaH方法，将寻求复应力函数的问题归结为求解正则型的奇异积分方程，并证明了其解的存在唯一，由于所用方法是构造性的，故有利于数值计算。     

用试探方程法求Jaulent-Miodek方程的新的精确行波解

利用试探方程法将Jaulent-Miodek方程约化为初等积分的形式,进而求出了该方程的精确行波解,其中包括椭圆函数双周期解和有理函数解等新解.     

开口弧段的双周期Riemann边值问题

一.问题、记号、引理 关于光滑封闭曲线的双周期Riemann边值问题已有充分的研究。这里讨论光滑开口弧段L_0上的类似问题,并将其应用于某些奇异积分方程。我们限定是一条光滑弧段,但所用的方法及结果不难推广到一般情形。     

关于双准周期解析函数的DIRICHLET问题

§1 引言 在[1]中,我们讨论了双周期解析函数的Dirichlet问题,将其化为Fredholm积分方程而给出了其求解方法,并得出了可解条件。我们也曾提到了准双周期解析函数的类似问题以及有关结果,但未予证明。本文将给出这些结果的详细论证。     

双周期裂纹场的不同材料弹性平面焊接问题

本文讨论双周期胞腔中含若干个任意形状裂纹的不同材料的弹性平面焊接问题,根据路见可和方法,对这类弹性平面问题建立起了数学模型,将求解弹性平衡问题化归为寻求复应力函数的问题,并把路见可给出的复Airy函数用于推广方法,更进一步地将寻求复应力函数的问题归结为求解正则型的奇异积分方程,最后证明了其解存在且唯一。     

带周期裂缝的弹性半平面问题

本文把具有任意形状和个数的周期裂缝的弹性半平面基本问题化为了某种特殊类型的奇异积分方程,证明了其解的存在和唯一。并对带周期共线直裂缝的弹性半平面问题,给出了封闭形式的解。     

复合材料焊接线出现裂缝的平面弹性基本问题

本文用复变方法讨论了复合材料任意形状焊接线上出现若干条裂缝时的平面弹性第一和第二基本问题，把寻求复应力函数的问题分别归结为求解某种正则型奇异积分方程和正则型奇异积分方程组，并证明了其解存在且唯一。     

凹角型区域椭圆边值问题的自然边界归化

In this paper, the natural boundary reduction for some elliptic boundary value problems with concave angle domains and their natural boundary methods are investigated. The natural integral equations and the Poisson integral formulae are given. The finite element methods of the natural integral equations are discussed in details. The convergences of the approximate solutions and their error estimates are obtained. Finally, some numerical examples are presented to show that our methods are effective.     

关于用定积分求解实际问题的方法讨论

本文给出了将部分重积分问题转化为定积分求解的一些推论，讨论了应用中运用“微元法”解决实际问题的方法。     

Boundary Value Problems for Quasielliptic Equations in a Half-Space

We consider general boundary value problems with data on the boundary of a half-space for quasielliptic equations with constant coefficients. We find integral representations for solutions and study some properties of the kernels of the corresponding integral operators. The results are applied to proving some generalization of the Miranda-Agmon maximum principle.     

On the Existence of a Classical Optimal Solution and of an Almost Strongly Optimal Solution for an Infinite-Horizon Control Problem

We consider an infinite-horizon optimal control problem with the cost functional described either by an integral over an unbounded interval (a Lebesgue integral) or by a limit of integrals (an improper Lebesgue integral). We prove some theorems on the existence of solutions to such problems. The proofs are based on appropriate lower closure theorems and some extensions of Olech’s theorem on the lower semicontinuity of an integral functional; these extensions cover the cases of functionals described by an integral over an unbounded interval and by a limit of integrals.     

On the numerical solution of linear and nonlinear volterra integral and integro-differential equations

Sinc bases are developed to approximate the solutions of linear and nonlinear Volterra integral and integro-differential equations. Properties of these sinc bases and some operational matrices are first presented. These properties are then used to reduce the integral and integro-differential equations to systems of linear or nonlinear algebraic equations. Numerical examples illustrate the pertinent features of the method and its applicability to a large variety of problems. The examples include convolution type, singular as well as singularly-perturbed problems.     

Some new explicit bounds for weakly singular integral inequalities with applications to fractional differential and integral equations

Some new weakly singular integral inequalities of Gronwall-Bellman type are established, which generalized some known weakly singular inequalities and can be used in the analysis of various problems in the theory of certain classes of differential equations, integral equations and evolution equations. Some applications to fractional differential and integral equations are also indicated.     

泛函积分方程的正解与应用

运用锥拉伸与压缩不动点定理,研究一类泛函积分方程的正解．把所得结果应用于研究常微分方程积分边值问题正解的存在性,所得结果推广和本质上改进了马如云等作者最近的一些结果．     

多项式插值与Rolle定理

本文利用多项式插值 ,对微分学和积分学中的一些典型题目 ,给出了统一的处理方法 .这种方法易于模仿 ,有一定的适用性 .     

Integral points, divisibility between values of polynomials and entire curves on surfaces

We prove some new degeneracy results for integral points and entire curves on surfaces; in particular, we provide the first examples, to our knowledge, of a simply connected smooth variety whose sets of integral points are never Zariski-dense. Some of our results are connected with divisibility problems, i.e. the problem of describing the integral points in the plane where the values of some given polynomials in two variables divide the values of other given polynomials.