带转向点的非线性系统的奇摄动

本文考虑如下非线性系统εＹ″＝Ｆ（ｔ，Ｙ，Ｙ′，ε），－１＜ｔ＜１，Ｙ（－１，ε），Ｙ（１，ε）＝设Ｆ的部分或所有的分量ｆ．满足，称Ｆ在ｔ＝０处具有一般的转点．本文讨论系统在Ｆ具有一般转点时解存在的充分条件且研究解在转向点ｔ＝０处的渐近性态．对于内部层、边界层现象分别进行了讨论．     

一类Dirichlet边值问题的正解存在性

本文对Ｄｉｒｉｃｈｌｅｔ边值问题ｙ″－ｆ（ｔ，ｙ）＝０，ｙ（０）＝ｃ＞０，ｙ（１）＝ ０，给出正解的存在性结论，其中函数ｆ（ｔ，ｙ）可以是变号函数，并且可能在ｙ＝０处具有奇异性．     

一类n阶拟线性奇异摄动边值问题的一致有效渐近展开

本文研究一类ｎ阶拟线性奇异摄动边值问题：εｙ（ｎ）＝ｆ（ｔ，ε，ｙ，…，ｙ（ｎ－２）ｙ（ｎ－１）＋ｇ（ｔ，ε，ｙ，…，ｙ（ｎ－２），ｐｊ（ε）ｙ（ｊ）（０，ε）－ｑｊ（ε）ｙ（ｊ＋１）（０，ε）＝αｊ（ε）（０≤ｊ≤ｎ－２），ｂ１（ε）ｙ（ｎ－２）（１，ε）＋ｂ２（ε）ｙ（ｎ－１）（１，ε）＝β（ε），其中ε＞０为小参数．在较一般的条件之下，应用Ｂａｎａｃｈ／Ｐｉｃａｒｄ不动点定理证明了摄动解的存在性及局部唯一性，并给出了摄动解直到ｎ阶导函数的一致有效渐近展开式，推广和改进了已有的结果［１－５］．     

巧用函数单调性解赛题

函数ｆ（ｘ）在区间［ａ,ｂ］上单调增加（或单调减少）,又ｃ、ｄ∈［ａ,ｂ］上,若ｆ（ｃ）＝ｆ（ａ）,则有ｃ＝ｄ．１　求代数式的值例１　已知ｘ、ｙ∈［－π４,π４］,ａ∈Ｒ,且　ｘ３＋ｓｉｎｘ－２ａ＝０４ｙ３＋ｓｉｎｙｃｏｓｙ＋ａ＝０则ｃｏｓ（ｘ＋２ｙ）＝　　．（１９９４年全国高中数学竞赛题）解　由已知条件,可得　　ｘ３＋ｓｉｎｘ＝２ａ（－２ｙ）３＋ｓｉｎ（－２ｙ）＝２ａ故可设函数ｆ（ｔ）＝ｔ３＋ｓｉｎｔ,则有ｆ（ｘ）＝ｆ（－２ｙ）＝２ａ．由于函数ｆ（ｔ）＝ｔ３＋ｓｉｎｔ,在［－π２,π２］上是单…     

关于奇性两点狄利克雷问题

本文研究奇性两点狄利克雷问题，在ｆ（ｔ，ｘ，ｙ）≤α（ｔ）ｇ（ｘ）＋β（ｔ）ｈ（ｘ）｜ｙ｜ε，０＜ε≤２情形下，得到了解的存在性定理，推广了Ｔｉｎｅｏ（１９９２）的结果．     

ON THE COEFFICIENTS APPEARING IN THE EXPANSION OF MELNIKOV FUNCTIONS IN HOMOCLINIC BIFURCATIONS

Ｃｏｎｓｉｄｅｒａｐｌａｎａｒｐｅｒｔｕｒｂｅｄｓｙｓｔｅｍｏｆｔｈｅｆｏｒｍｘ＝Ｈｙ＋εｆ（ｘ，ｙ），ｙ＝－Ｈｘ＋εｇ（ｘ，ｙ）（１）ｗｈｅｒｅＨ，ｆ，ｇａｒｅｆｕｎｃｔｉｏｎｓｏｆｃｌａｓＣ∞．Ａｓｕｍｅｆｏｒε＝０（１）ｔｏｈａｖｅａｈｏｍｏｃ...     

算子方程解的稠密性及半线性系统的近似可控性

本文利用Ｂａｎａｃｈ不动点定理和Ｓｃｈａｕｄｅｒ不动点定理研究如下算子方程解的稠密性：ｙ＝ｙ０＋ＬＦ（ｙ）＋ＬＨ（ｖ）（其中，Ｌ、Ｈ为线性算子，Ｆ为非线性算子），然后，利用所得结论讨论Ｂａｎａｃｈ空间内的半线性系统：ｘ＇（ｔ）＋Ａ（ｔ）ｘ（ｔ）＝ｆ（ｔ，ｘ（ｔ）＋Ｂｕ（ｔ）的近似可控性。     

非线性Robin边值问题的奇摄动

本文应用微分不等式的方法，研究非线性Ｒｏｂｉｎ边值问题：ａ（ｘ，ｙ，ｙ′，ε）ｙ″＝ｆ（ｘ，ｙ，ｙ′，ε），０＜ｘ＜１，ｐ１ｙ（０，ε）－ｐ２ｙ′（０，ε）＝Ａ（ε），ｑ１ｙ（１，ε）＋ｑ２ｙ′（１，ε）＝Ｂ（ε），｛其中ε＞０是小参数，在适当的假设条件下，我们证明了上述问题解ｙ（ｘ，ε）的存在性和渐近估计式．     

函数f（t）＝ψ（t）／θ（t）值域的一种图示解法

函数ｆ（ｔ）＝ψ（ｔ）／θ（ｔ）值域的一种图示解法王友金（河北省青龙县职教中心）对于函数，若令ｘ＝θ（ｔ），ｙ＝（ｔ），则参数方程表示的曲线Ｃ：ｇ（ｘ，ｙ）＝０上任一点Ｐ（ｘ，ｙ）与原点Ｏ所在约直线ＯＰ的斜率为．由此及曲线上Ｐ点的任意性，通过讨论直线...     

具有奇性的常微分方程的边值问题

本文对具有奇性的常微分方程的边值问题（ｔ）ｙ'=(ｔ，ｙ，ｙ＇），ｙ（０）＝ａ，ｙ（１）＝ｂ建立了Ｎａｇｕｍｏ型存在定理．     

L-层次拓扑空间

在L-拓扑空间中,利用Dα-闭集推广了远域的概念,定义了L-子集的层次收敛,建立了网的层次收敛理论.     

Nonmonotone Interior Layer Solutions for Singularly Perturbed Semilinear Boundary Value Problems with a Turning Point

ＮｏｎｍｏｎｏｔｏｎｅＩｎｔｅｒｉｏｒＬａｙｅｒＳｏｌｕｔｉｏｎｓｆｏｒＳｉｎｇｕｌａｒｌｙＰｅｒｔｕｒｂｅｄＳｅｍｉｌｉｎｅａｒＢｏｕｎｄａｒｙＶａｌｕｅＰｒｏｂｌｅｍｓｗｉｔｈａＴｕｒｎｉｎｇＰｏｉｎｔＷｅｉＢａｏｓｈｅ（魏宝社）（Ｄｅｐａｒｔｍ...     

Some remarks on Prandtl system

The purpose of this paper is to correct some drawbacks in the proof of the well-known Boundary Layer Theory in Oleinik’s book. The Prandtl system for a nonstationary layer arising in an axially symmetric incopressible flow past a solid body is analyzed. This paper was supported by NSF of China (10571144), NSF for youth of Fujian province in China (2005J037) and NSF of Jimei University in China.     

L-拓扑空间的层仿紧性

在L-拓扑空间中定义了一种新型的仿紧性,即层仿紧性,并研究其性质,讨论了这种仿紧性与已有的两种仿紧性之间的关系.     

Boundary integral equations in time-dependent bending of thermoelastic plates

The initial-boundary value problems with the Dirichlet and Neumann boundary conditions arising in the theory of bending of thermoelastic plates with transverse shear deformation are reduced to time-dependent boundary integral equations by means of layer potentials. The solvability of these equations is then investigated in Sobolev-type spaces.     

A Besov Space Mapping Property for the Double Layer Potential on Polygons

A classical boundedness property for the double layer potential on polygons with respect to Sobolev spaces is extended to a scale of Besov spaces which is related to adaptive restricted nonlinear approximation schemes.     

Wiring edge-disjoint layouts

We consider the wiring or layer assignment problem for edge-disjoint layouts. The wiring problem is well understood for the case that the underlying layout graph is a square grid (Lipski Jr. and Preparata, 1987). In this paper, we introduce a more general approach to this problem. For an edge-disjoint layout in the plane, respectively in an arbitrary planar layout graph, we give equivalent conditions for k-layer wirability. Based on these conditions, we obtain linear-time algorithms to wire every layout in a tri-hexagonal grid or a tri-square-hexagonal grid, respectively, using at most five layers.     

L-Fuzzy拓扑空间的层分离性公理

在一般L-fuzzy拓扑空间中引入一套新的分离性公理。即层分离性公理。并研究其性质．讨论层分离性公理与L-fuzzy拓扑空间中的第一套分离性公理间的关系。表明前者比后者弱且两者有很好的协调性。     

LAYER STRIPPING METHOD FOR POTENTIAL INVERSION

1.IntroductionThepotentialinversionproblemofthefollowingPlasmawaveequationisdiscussedinthispaper:Thatis,givinganimpulseatthesurfacez~0,todeterminethewavefieldpandpotentialvfromtheimpulseresponseh.TherearethreekindsofinverseproblemsofthisPlasmawaveequation:(1)TOdeterminethedifferentialequationfromitsspectralfunction[1];(2)Todeterminethepotentialfromthewavefunctionformatlargedistance.Itistheso--calledinversescatteringproblem[2,3];(3)TOdeterminethepotentialfromtheresponseontheboundarytoaunitim…     

A brief survey on numerical methods for solving singularly perturbed problems

In the present paper, a brief survey on computational techniques for the different classes of singularly perturbed problems is given. This survey is a continuation of work performed earlier by the first author and contains the literature of the work done by the researchers during the years 2000-2009. However some older important relevant papers are also included in this survey. We also mentioned those papers which are not surveyed in the previous survey papers by the first author of this paper, see [Appl. Math. Comput. 30 (1989) 223-259, 130 (2002) 457-510, 134 (2003) 371-429] for details. Thus this survey paper contains a surprisingly large amount of literature on singularly perturbed problems and indeed can serve as an introduction to some of the ideas and methods for the singular perturbation problems.