二阶奇异积分边值问题的正解

By using the fixed point index in cone and the fixed theorem of cone expansion and compression, the existence of positive solutions to the singular second-order boundary value problem is considered.     

ASYMPTOTIC SOLUTION TO SINGULARLY PERTURBED DELAYED EQUATION FOR PREDATOR-PREY MODEL

A kind of singularly perturbed delayed equation for predator-prey system is consi- dered. According to the boundary layer function method and the singular perturbation theory, we construct an asymptotic expansion of the solution to the original equation.     

A CLASS OF SINGULARLY PERTURBED INITIAL BOUNDARY PROBLEM FOR REACTION DIFFUSION EQUATION

The singularly perturbed initial boundary value problem for a class of reaction diffusion equation is considered. Under appropriate conditions, the existence-uniqueness and the asymptotic behavior of the solution are showed by using the fixed-point theorem.     

A boundary expansion of solutions to nonlinear singular elliptic equations

In this paper we establish an asymptotic expansion near the boundary for solutions to the Dirichlet problem of elliptic equations with singularities near the boundary.This expansion formula shows the singularity profile of solutions at the boundary.We deal with both linear and nonlinear elliptic equations,including fully nonlinear elliptic equations and equations of Monge-Ampère type.     

Positive solution of singularly perturbed Dirichlet problem with singularities

A class of singularly perturbed boundary value problem with singularities is considered. Introducing the stretched variables, the boundary layer corrective terms near x = 0 and x = 1 are constructed. Under suitable conditions, by using the theory of differential inequalities the existence and asymptotic behavior of solution for boundary value problem are proved, uniformly valid asymptotic expansion of solution with boundary layers are obtained,     

Extrapolation methods to compute hypersingular integral in boundary element methods

The composite trapezoidal rule for the computation of Hadamard finite-part integrals in boundary element methods with the hypersingular kernel 1/sin 2(x-s) is discussed,and the main part of the asymptotic expansion of error function is obtained.Based on the main part of the asymptotic expansion,a series is constructed to approach the singular point.An extrapolation algorithm is presented and the convergence rate is proved.Some numerical results are also presented to confirm the theoretical results and show the efficiency of the algorithms.     

POSITIVE RADIAL SOLUTIONS OF FULLY NONLINEAR ELLIPTIC EQUATIONS IN R^n

By the Schauder-Tychonoff fixed-point theorem, we investigate the existence and asymptotic behavior of positive radial solutions of fully nonlinear elliptic equations in R^n. We give some sufficient conditions to guarantee the existence of bounded and unbounded radial solutions and consider the nonexistence of positive solution in R^n.     

无穷区间上一阶奇异微分方程正解的存在性和不可比较性

By constructing a special cone and applying the fixed point theorem of cone compression and expansion, this paper investigates the existence of positive solutions for a class of first order singular boundary value problem （BVP, for short） on unbounded domains. Moreover, an incomparable result about two positive solutions for the BVP is also obtained and an example is given to illustrate the application of the main results.     

On a Problem of D. H. Lehmer

The main purpose of this paper is to use the Fourier expansion for character sums and the mean value theorem of Dirichlet L-functions to study the asymptotic property of the difference between a D. H. Lehmer number and its inverse modulo p （an odd prime）, A interesting mean square value formula is also given.     

MULTIPLE LAYER BEHAVIOR OF BOUNDARY VALUE PROBLEM FOR SINGULARLY PERTURBED n-TH ORDER NONLINEAR DIFFERENTIAL EQUATION

In this paper,we study the singular perturbation of boundary value problem for a class of n-th order nonlinear differential equation,the solution is shown to exhibit multiple layer behavior.According to different layers and by introducing extended variable,we obtain the uniformly effective asymptotic expansion with different boundary layer correction term.     

二阶拟线性方程边值问题的奇摄动

本文借助不动点原理 ,对二阶拟线性方程的边值问题的渐近解做了估计 ,得到了包括边界层在内的任意次近似的一致有效的渐近展开式     

三阶非线性两点边值问题的奇摄动

本文借助不动点原理,对一类三阶非线性方程的边值问题的渐近解做了估计,得到了包括边界层在内的任意次近似的一致有效的渐近展开式。     

不动点定理在奇摄动非线性初值问题的套层解中的应用

Singularperturbationofnonlinearboundaryvalueproblemswhichhavedoubleboundarylayerpropertieswerediscussedbysomeauthorsusingthemethodofdifferentialinequali ties[1 ] -[3 ] .Nonlinearboundaryvalueproblemswhichhavenotdoubleboundarylayerpropertieswerediscussedbysomeauthorsusingthemethodofthefixed_pointtheorem[4] -[6 ] .Inthispa perwewillusethefixed_pointtheoremtodiscussthethirdorderdifferentialequationswhichhavedoubleinitiallayer.Weconsiderthefollowingproblem .ε4y =h(t,y,εy′,ε2 y″,ε) ,t∈ [0 ,T…     

一类具非线性边值条件的微分方程的奇摄动问题

研究了一类非线性三阶微分方程的奇摄动问题.运用合成展开法构造了问题的形式渐近解,并运用不动点原理证明了原问题解的存在性及所得形式渐近解的一致有效性.     

一类具有不连续源的奇摄动半线性微分方程组边值问题

讨论了一类具有不连续源的奇摄动半线性微分方程组边值问题,构造了形式渐近解.利用Hartman-Nagumo不等式证明了奇摄动半线性微分方程组的解的存在性与唯一性,利用Aumann介值定理,得到了该方程组解的光滑性,并且得到了一致有效估计.     

半线性奇摄动椭圆型方程边值问题的渐近解

本文运用了边界层函数构造了一类半线性奇摄动椭圆型方程边值问题解的渐近展开式，并证明了该展开式达到任一精度的一致有效性．     

A Class of Singularly Perturbed Semilinear Elliptic Equations

The singularly perturbed problem for the semilinear elliptic equations is considered. Under appropriate conditions, by using the comparison theorem, the existence and asymptotic behavior of solution for the boundary value problems are studied.     

一类高阶拟线性椭圆型方程奇摄动边值问题

本文讨论了一类拟线性椭圆型方程奇摄动Dirichlet边值问题．在适当的条件下，利用不动点定理，研究了边值问题解的存在唯一性及其渐近性态．     

一类半线性椭圆型方程奇摄动Robin边值问题

The singularly perturbed Robin boundary value problems for the semilinear elliptic equation are considered. Under suitable conditions and by using the fixed point theorem the existence ,uniqueness and asymptotic behavior of solution for the boundary value problems are studied.     

拟线性椭圆型方程奇摄动边值问题

本文讨论了拟线性椭圆型方程奇摄动Robin边值问题。在适当的条件下，利用不动点定理，研究了边值问题解的存在唯一性及其渐近性态。