具有旋度边界条件的抛物方程组

证明一个线性抛物方程组的整体古典解的存在唯一性，困难在于边界条件中含有未知向量函数的旋度．     

具有非线性边界条件的奇摄动边值问题

本文研究如下的奇摄动边值问题: εx″=f(t,x,x′,ε) g(x(0),x′(0),ε)=A(ε),h(x(1),x′(1),ε)=B(ε),其中ε>0是小参数,f(t,x,y,ε),g(x,y,ε),h(x,y,ε),A(ε),B(ε)适当光滑。我们用微分不等式方法证明了解的存在唯一性,并给出了解的一致有效估计。     

具有广义边界条件的迁移方程的性质

研究迁移理论中一类具有广义周期边界条件,非均匀介质板几何的定态迁移方程,证明了迁移算子是预解正算子,得到了微分算子的共轭算子及共轭算子的定义域.证明了迁移算子的共轭算子定义域的正锥在共轭空间的正锥中共尾.最后证明了迁移算子的增长界等于其谱界.     

应用功的互等定理求解具有复杂边界条件的矩形板的挠曲面方程

本文指出,在一定的条件下,功的互等定理等价于位移叠加原理.在[6]的基础上进一步推广了功的互等定理的应用,因而为求解在复杂受力情况下,具有复杂边界条件的矩形板和直梁的挠曲面方程提供了一个简便、通用的新计算方法.     

具有Neumann边界条件热方程组的爆破速度

本文考虑具有 Ｎｅｕｍａｎｎ边界条件 ｕ／ｎ＝ｅｖ, ｖ／η＝ｅｕ在 ＳＲ ×（０,Ｔ）热方程组。ｕｔ＝△ｕ,ｖｔ=△ｖ在ＢＲ×（０,Ｔ）解的爆破性质·我们给出了爆破速度估计并证明了爆破仅在边界上发生．     

弹性约束边界条件下矩形蜂窝夹芯板的自由振动分析

蜂窝夹芯板在飞行器、高速列车等领域有广泛的用途，对其开展振动分析具有明确的科学价值及工程意义.为区别于诸简支等传统约束边界，提出了弹性约束边界下蜂窝夹芯板结构的自由振动特性分析方法.具体来说，首先通过将蜂窝夹芯层等效为各向异性板，将夹芯板问题转变为三层板结构.进一步地，将板结构的位移场函数由改进的二维Fourier级数表示，并基于能量原理的Rayleigh Ritz法得到结构的固有频率和固有振型，理论预测结果与数值模拟分析吻合较好.提出的理论模型可用于系统讨论约束边界对蜂窝夹芯结构自由振动特性的影响，为此类结构的约束方案设计提供理论依据.     

一类具有Neumann边界条件的曲率方程解的估计

研究了一类具有Neumann边界条件的抛物方程解的性质,通过微分方法得到了一类边值问题解的估计,并得到了拟线性方程解的存在性.     

一类具有动力边界条件的进化方程解的衰减性

本文研究了一类具有动力边界条件的方程解的衰减性.利用能量扰动法,得到了解的衰减性与外力f(x,t)之间的关系,即它们具有相同的指数衰减性和代数衰减性.     

具有非线性边界条件的向量边值问题的奇摄动

该文利用微分不等式理论证明了具有非线性边界条件的非线性系统摄动解的存在，并给出了解的按分量直到O（εN 1）的一致有效的估计．     

具有非线性边界条件的奇摄动微分系统边值问题

研究了一类具有非线性边界条件的奇摄动半线性微分系统边值问题．利用边界层校正法构造了形式渐近解．并且在适当的假设下,用微分不等式理论,证明了解的存在性及其一致有效性．     

Exact Boundary Controllability for the Spatial Vibration of String with Dynamical Boundary Conditions

This paper deals with the spatial vibration of an elastic string with masses at the endpoints. The authors derive the corresponding quasilinear wave equation with dynamical boundary conditions, and prove the exact boundary controllability of this system by means of a constructive method with modular structure.     

任意边界条件下圆柱厚壳自由振动分析的空间变量变换法

本文提出一种一般解析方法——空间变量变换法,用以求解任意边界条件下圆柱厚壳自由振动问题.运用本文方法对悬臂圆柱厚壳的自振特性作了计算,计算结果与薄壳理论相应结果及试验值作了比较.理论分析和计算结果表明,本文方法具有很好的收敛性和精确性,可以推广用于分析梁、板、壳的自由振动.     

On the Existence of Countably Many Periodic Solutions of a Boundary Value Problem for the Beam Vibration Equation with Homogeneous Boundary Conditions

Differential Equations - The existence of infinitely many periodic solutions of the quasilinear beam vibration equation is proved for the case in which the nonlinear term is a homogeneous odd...     

Boundary Value Problems with Compatible Boundary Conditions

If Y is a subset of the space ℝⁿ × ℝⁿ, we call a pair of continuous functions U, V Y-compatible, if they map the space ℝⁿ into itself and satisfy Ux · Vy ≥ 0, for all (x, y) ∈ Y with x · y ≥ 0. (Dot denotes inner product.) In this paper a nonlinear two point boundary value problem for a second order ordinary differential n-dimensional system is investigated, provided the boundary conditions are given via a pair of compatible mappings. By using a truncation of the initial equation and restrictions of its domain, Brouwer's fixed point theorem is applied to the composition of the consequent mapping with some projections and a one-parameter family of fixed points P _δ is obtained. Then passing to the limits as δ tends to zero the so-obtained accumulation points are solutions of the problem.     

On a Nonlocal BVP with Nonlinear Boundary Conditions

We consider the existence of at least one positive solution of the problem ${-y''(t)=f(t,y(t)), y(0)=H_1(\varphi(y))+\int_{E}H_2(s,y(s))\,ds, y(1)=0}$ , where ${y(0)=H_1(\varphi(y))+\int_{E}H_2(s,y(s))\,ds}$ represents a nonlinear, nonlocal boundary condition. We show by imposing some relatively mild structural conditions on f, H ₁, H ₂, and ${\varphi}$ that this problem admits at least one positive solution. Finally, our results generalize and improve existing results, and we give a specific example illustrating these generalizations and improvements.     

On a Discrete Fractional Boundary Value Problem with Nonlocal Fractional Boundary Conditions

In this paper, we investigate the nonlinear fractional difference equation with nonlocal fractional boundary conditions. We derive the Green＇s function for this problem and show that it satisfies certain properties. Some existence results are obtained by means of nonlinear alternative of Leray-Schauder type theorem and Krasnosel-skii＇s fixed point theorem.     

Heat Transfer in a Region with Non-Uniform Boundary Conditions

Heat transfer in a rectangular region with non-uniform conditions on the walls is considered. The temperature is given on both vertical walls and a part of the upper wall. The remainder of the upper wall and the lower horizontal wall are perfectly insulated. This boundary value problem is reduced to dual Fourier series equations. Those equations are simplified under the assumption that the height of the region is greater than the length or comparable to it. An exact solution of the simplified equations is constructed by using the Schwinger transformation, which has been used successfully in analyzing the electro-dynamics of wave guides. Numerical solutions also are found using a commercial finite element solver and a finite difference solver written in FORTRAN. Results for the average temperature and the temperature distribution in the region for a variety of high temperature boundary locations are in very good agreement among the three solution techniques.     

半无限及含孔无限平面在各种边界条件下的复位势基本解*

运用Riemann-Schwarz对称原理和线弹性力学解的叠加原理建立了半无限平面及含孔无限平面在各种边界条件下基本解的一般求解方法,并分别导出边界上受不同荷载以及边界固定等各种边界条件下的复位势基本解。     

Three-Dimensional Boundary Value Problems of Elastothermodiffusion with Mixed Boundary Conditions

We investigate the basic boundary value problems of the connected theory of elastothermodiffusion for three-dimensional domains bounded by several closed surfaces when the same boundary conditions are fulfilled on every separate boundary surface, but these conditions differ on different groups of surfaces. Using the results of papers [1–8], we prove theorems on the existence and uniqueness of the classical solutions of these problems.