存在性定理

In this article, we mainly discuss the asymptotic behavior, existence for nonoscillatory solutions and comparison theorems for oscillation.

本文主要讨论测度链上高阶时滞动力方程的渐近性、非振动解的存在性以及振动性的比较定理。

For the homoclinics taking on values in the unbounded domain, in order to apply the usual "Mountain Pass " theorem, A compact embedding theorem is proved.

为克服同宿解取值于无界域而缺乏自然紧性，证明了一个紧嵌入定理，从而可以利用通常的山路引理与对称山路引理获得同宿解的存在性与多重性条件。

We improved the merit function in quasi-feasible interior point method and used the exponential function that is the more general function to prove the existence of one order optimality point in feasible problem. We discussed the inner and outer algorithms and made the convergence theorem.

在算法中改进了拟可行内点法中的值函数，使用指数形式的更一般函数，用此值函数证明了可行性问题的一阶最优性点的存在性，并通过对内部算法及外部算法的讨论得到了算法的收敛性定理。

All the known results about analytic solutions for iterative functional differential equations are obtained by the majorant series and the Banach fixed point theorem.

本文的第三章首先利用不动点定理得到了一类迭代泛函微分方程高阶光滑解的存在性、唯一性和关于已知函数的连续依赖性定理，得到了与常微分方程类似的结论。

On the base that two comparison theorems are established,applying the fixed-point theorems,we investigate the existence of maximal and minimal solutions forfirst order initial value problem and the JKjperiodic boundary value problem of discontinuous differential-integral equations of mixed type in partial-ordered Banach spaces,respectively.

在建立了两个比较定理的基础上，我们应用不动点定理，分别研究了半序Banach空间中不连续的一阶混合型微分-积分方程的初值问题与周期边值问题最大解与最小解的存在性。

II, Polynomial rings on a general field( on contrast of those over a number field): concepts of ring, ideals, field and several special rings as domains, principal ideal domains and unique factorization domains, the unique factorization theory of polynomial rings.

二、一般域上的多项式理论（是数域上多项式理论的推广）：学习环、域和几类特殊结构的环（整环、主理想环，唯一分解环等）的概念，多项式环的唯一分解定理；三、线性代数：讲述一般数域上的向量空间理论（是数域上向量空间理论的继续和推广），模的概念，主理想环上的模的结构及其线性变换的若当标准型等；四、一元多项式的解及域论：学习域扩张及其相关概念，伽罗瓦理论，用伽罗瓦定理判断根式解的存在性。

In chapter II,the preliminary knowledgefor accomplishing this research is presented,and the well-posed problem ofthe thin-plate flow of non-Newtonian viscous fluids is testified.By using themonotone operator theory and Schauder's fixed point theorem,the generalizedsolution's existence and uniqueness theorem for the thin-plate flow problem ofnon-Newtonian viscous fluids is obtained under reasonable conditions.

第二章给出了进行本项研究所需的一些预备知识，对非牛顿粘性流体薄板流问题广义解的适定性进行了研究，应用单调算子理论和不动点定理，在合理的条件下，证明了非牛顿粘性流体薄板流问题广义解的存在性，唯一性定理。

We discussed the stability of the system balance, used the Poincare-Bendixson's annular region theorem to prove the existence, and used the Zhang Zhifen unicity theorem to prove the uniqueness of limit cycle, at the same time give meaning to the corresponding conclusions on the ecology.

讨论了系统平衡点的稳定性，用Bendixson环域定理证明极限环的存在性，借助张芷芬唯一性定理证明极限环的唯一性，同时对相应结论的生态学意义给予说明。

The aim of this thesis is to study the existence of positive solutions of boundary value problem for nonlinear second order ordinary differential equations , mainly using the fixed point index theory in a cone. The conditions of the existence of positive solutions of the boundary value problem are given in the thesis. We improve the result of the existence of positive solutions either in the sublinear or in the superlinear conditons.

本文主要利用锥上不动点指数定理，解决非线性二阶常微分方程边值问题的正解的存在性问题，并给出了边值问题正解存在的条件，改进了次线性和超线性条件下正解存在的结论。

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。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。