边界点

The existence and uniqueness of the solution with the help of the Banach fixed point theorem and the theory of operator semigroups are verified .The global exponential stability of KS equation and the global exponential stability and asymptotical stability of macro KS equation with the given boundary feedbacks are proved .

通过Banach不动点原理和算子半群理论证明了方程解的存在性和唯一性，并证明了KS方程在给定的边界反馈条件下是全局指数稳定的及广义的KS方程在给定的边界反馈条件下是全局指数稳定和渐近稳定的。

The physical meanings of BEM are extended by the FBEM and FPFM. On the basis of solving plane problems sueessfully with FBEM and FPFM, the article recommends the fictitious boundary element method and fictitious point force method to solve three dimensions problem in solid mechanics.

本文对边界单元法进行了改进，提出了使用方便、灵活、物理意义清晰的虚边界单元法和点载荷法，较好地解决了局部数值解精度不高的问题，并将所提出的方法推广应用到求解三维问题，减少了问题的复杂性。

Studied present measuring methods" advantages and disadvantages, and presented the necessity and importance of researching propellant transient heat transfer.2.according to 130 and aeronautic 90 rocket projectiles" structure, analysed and acquired physical and mathematical models for propellant transient heat transfer, also designed propellant temperature field simulation units for test.3.acquired discrete transient heat balance equation and temperature calculation program, and gave contrasting curves between experimental temperature values and program calculating temperature values as well as maximum errors and average square root errors between them.4.by programs based on the first class boundary condition, worked out temperature distribution in propellant temperature field simulation units at different time, analysed temperature field distribution law and main elements affecting heat transfer, acquired propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.5.established transient heat transfer mathematical model and temperature calculation program for the third class boundary condition, drew contrasting curves between temperature experimental values and calculation values and gave maximum errors and average square root errors between them, got temperature distribution in the simulation unit at different time and main elements affecting heat conduction, figured out propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.

分析了现有测试方法的优缺点，提出了研究推进剂瞬态导热的必要性和重要性。 2。根据130和航90两种火箭弹的结构，分析得到了推进剂传热的物理模型和数学模型，设计了推进剂温度场模拟实验装置。 3。得到了离散形式的瞬态热平衡方程和温度场计算程序，给出了实验温度与程序计算温度值的对比曲线及其最大偏差与均方差。 4。利用程序求出了第一类边界条件下、不同时刻推进剂温度场模拟装置中的温度分布，分析了温度场的分布规律和影响传热的主要因素，求出了推进剂质量加权平均温度和最大肉厚1／2处的温度时间曲线并给出了两者之间的最大偏差与均方差。 5。建立了第三类边界条件下的瞬态导热数学模型和温度计算程序，求出了温度实测值与计算值的对比曲线并给出了两者之间的最大偏差与均方差，得到了不同时刻温度场模拟装置的温度分布与影响导热的主要因素，求出了推进剂质量加权平均温度和最大肉厚1／2处温度及两者之间的最大偏差与均方差，讨论并确定了能代表130和航90推进剂温度的特征点的位置。

For each potential instability mode,a critical point on the boundary of the security region was found,in which the normal vector was used to form the hyperplane to simulate the boundary of the s.

对每一种潜在的失稳模式，搜索其动态安全域边界上的一个点，根据临界点处的法向来求解用于模拟动态安全域边界的超平面。

The nearly singular integral occurs in the boundary element formulation when a source point is close to the integration element but not on this element.

边界元法中存在几乎奇异积分的计算困难。引起边界单元上几乎奇异积分的因素是源点到其邻近单元的最小距离δ。

We present a new direct boundary integral equation in terms of the boundary magnetic field only.

文中提出了一个新的直接边界积分公式，仅仅由边界上的已知磁场值确定空间点的磁场值。

A boundary integral formulation describing constant-αforce-free field with finite energycontent in the semi-infinite space above the sun was proposed(Yan,1995), this formulationcontains boundary field and its normal gradient under integral sign.

颜毅华1995年在太阳物理杂志上发表一文，就太阳磁场提出了一个具有有限能量的线性无力场模型，并对磁场给出了一个边界积分表示公式，该公式用边界上的已知磁场值和未知的磁场法向导数值来确定空间任意点的磁场值。

In the first part of this paper, we give some basic concepts of regular Sturm-Liouville problems and some Sturm-Liouville problems with eigenparameter in the boundary conditions and the definition and properties of the Krein space. Using the Krein space, we describe a class of Sturm-Liouville problems with eigenparameter in two boundary conditions and prove that it can generate a self-adjoint operator in Krein space with only point spectrum.

第一部分我们介绍了一些基本概念如正则Sturm-Liouville问题、边界条件含参数的问题、Krein空间等，并利用Krein空间的定义和性质描述了一类参数边界条件的Sturm-Liouville问题，证明它可构造一Krein空间上的自伴算子，并且谱全为点谱。

If the fluid flow separated from the sharp edge of the rearward steps reattached in the effective region, the reseparated point would occur downstream of the cross section of the cylinder and the drag would be reduced.

对再附流动的有限级数解表明，由有效再附区开始的再附边界层能够保持其边界层状态，发展至柱面最大迎流截面之后的流动再分离点。

The following exciting results are revealed: 1 When considering the influence of some nonlinear elements such as hard-limit of exciters, the effects of some devices such as Power System Stabilizer and Static Var Compensator which can introduce positive damping in power system, the reasonability of system parameter values in simulation, the SNB surface and HB surface on the boundary of SSSR will turn close to each other and even coalesce together; 2 Under some conditions, coupling between slow exciters and shunt capacitors will bring negative damping in power system dynamics, which increases the possibility of oscillatory instability. So the power system with mass shunt compensators is easily subjected to the oscillatory instability. In recent years, chaotic phenomena of power system have been reported many times. Some simulation studies even found chaos existing inside the power system SSSR. In this dissertation, chaotic phenomena in power systems are thoroughly studied in order to make clear the relation of chaos and SSSR. The following results are derived: 1 Based on Li-Yorke Theorem and their definition on the chaos, the existence of chaos in power system is verified; 2 Three possible routes of causing chaos in power system are found and deeply investigated. They are route of cascading period doubling, route of directly initial energizing and route of torus bifurcation (or quasi-periodicity). The latter two routes are investigated for the first time in power system stability studies; 3 When the stability conditions of chaos are broken, it is found they can lead to voltage collapse, angle divergence, or voltage collapse with angle divergence simultaneously.

针对在电力系统小扰动稳定区域内可能存在混沌吸引域的有关报道，本文深入研究了电力系统混沌现象的出现途径和与系统失稳模式之间的关系：1利用Li-Yorke定理和Li-Yorke的混沌定义，从理论上证明了电力系统混沌现象的存在性；2发现了电力系统中导致混沌出现的三种可能途径：倍周期分岔导致混沌、初始能量直接激发混沌和经由环面分岔导致混沌，并对后两种新发现的途径进行了较为细致的研究；3发现了混沌极限环破裂导致电压崩溃、角度失稳以及电压崩溃和角度失稳同时出现的现象，其中混沌极限环破裂导致系统角度失稳和电压崩溃及角度失稳同时出现的现象均属首次报道；4证明由微分-代数方程描述的系统模型，其小扰动稳定域的边界只包含HB、SNB和SIB三种分岔界面，在SSSR的内部和边界上，均不可能存在会导致混沌的点，从而将混沌现象排除在小扰动稳定域的研究之外，简化了后者的研究工作。

For a big chunk of credit-card losses; the number of filings (and thus charge-off rates) would be rising again, whether

年美国个人破产法的一个改动使得破产登记急速下降，而后引起了信用卡大规模的亏损。

Eph. 4:23 And that you be renewed in the spirit of your mind

弗四23 而在你们心思的灵里得以更新