稳定性条件

The traditional stability analysis methods are based on the determinate initial parameter of power system.

传统的稳定性分析都是在系统的元件参数、运行条件及干扰方式已给定的情况下进行的，属于确定性的稳定性分析。

The first part presents develops of predator-prey systems and gives the model that is investigated in our paper; Chapter 2 presents the results on boundedness of solutions and permanence of system; In chapter 3, we explicitly derive a domain of attraction for the positive equilibrium of system by using Liapunov method; The local stability and the conditions that Hopf bifurcation occurs are obtained in chapter 4; In chapter 5, some explicit fomulae of the direction of Hopf bifurcation and the stability of bifurcating periodic solutions on the center manifold are determined,using normal form and center manifold introduced by Hassard et al; In chapter 6, some numerical simulations are performed to illustrate the analytical results found; Our paper ends with a brief conclusion.

全文共分七章，第1章对捕食-食饵系统的发展背景做了介绍并给出了本文研究的模型；第2章讨论了系统的保持性和解的有界性；第3章研究正平衡点的全局性质，对正平衡点的吸引域进行了精确估计；第4章研究了系统的正平衡点的局部稳定性和Hopf分支存在的条件；第5章利用规范型和中心流形定理得到了一个决定Hopf分支方向、分支周期解的稳定性及其他性质的精确公式；第6章对一个具体模型进行了数值模拟；第7章对全文进行了总结。

The model in this paper takes the form as belowThe main contents and results in this paper are as follows:In section 1, we state our main analytical results on equilibria of the above system. First, several sufficient conditions for coexistence of the steady-state are given by the standard fixed-point index theory in cone. Second, the global structure of the coexistence solutions and their local stability are established by using bifurcation theory. Third, the multiplicity, uniqueness and stability of positive steady-state solutions to this system are derived by means of perturbation theory of eigenvalues, standard regularity theory, Sobolev embedding theorem and fixed-point index theory.

本文主要有两章内容：第一章研究了该模型正平衡解的性质，可分为三部分：第一部分运用极值原理、上下解方法和锥映射不动点指标理论得到正平衡解存在的充分条件；第二部分利用分歧理论给出了平衡态系统正分歧解的结构，并讨论了局部分歧解的稳定性；第三部分利用特征值扰动理论、标准椭圆正则化理论、Sobolev嵌入定理及指标理论讨论了正平衡解的多重性、唯一性及稳定性，并讨论了参数对解的影响。

Also the problems of stochastic controllability, observability and stability of the filter are studied, a simple observability criterion for the time-invariant systems is set up, error band of the filtering is given theoretically, and the filtering stability results are proved under more general conditions; besides, the filtering error caused by uncorrect mathematical models is analysed.

本文还研究了随机能控能观性及滤波的稳定性问题，建立了结构简单的平稳定常系统的能观性判据，在理论上给出了滤波算法的误差范围，在更一般的条件下证明了最优滤波算法的稳定性；并从理论上分析了模型误差对滤波产生的影响。

There was no enough evidence to prove the allelopathic effects in eucalypt trees.(4) The effect of eucalypt on ecosystem stability of the soil was caused b

桉树对土壤生态稳定性的影响受客观条件和人为经营共同决定的，桉树本身并不是导致土壤生态稳定性降低的主要原因。

Subsequently, the absolute stability criteria for the closed loop system subject to sector-bounded condition are derived by use of Lyapunov functional method and linear matrix inequality technique.

应用Lyapunov稳定性理论和线性矩阵不等式工具，分析了各子系统在有扇形条件约束的绝时稳定性，同时得到网络控制系统全局稳定运行的最大允许时延界。

The results indicated that the thermal stability of thepolymers is greatly associated with the structure of the modified groups.Moreover, the imide- derivatives have greater thermal stability than thecorresponding amide- derivatives. This can provide useful information on thepreparation and processing of this kind of polymers.

用PyGC-MS对酰胺型和酰亚胺型改性聚乙烯在加工条件下的热分解产物进行了定性和定量的测定，结果表明不同改性基团对聚合物热稳定性有很大影响，酰亚胺型改性聚乙烯的热稳定性大于酰胺型，这为该类聚合物的制备加工和应用提供了有用的信息。

Because the carbonyl in its structure is with strongly absorb-electron effect, so it is a kind of non-proton polarity solvent with high boiling point, high flash point and low melting point, use conveniently for many processing operation such as filtration, distillation, solvent extraction, and so on; it is with very low toxicity, so the harm to human body is inappreciable, and reduce the environment pollution; due to its very strong dissolvability, it can dissolve organic matter, inorganic matter, resin, polymer, etc., and activate all kinds of reagent, mix to dissolve the other high boiling point solvents; it is with very good stability, it is stable under the hot strong alkali and acidity condition, it is with water-resistance and light, oxygen stability.

246℃ m.p：—20℃闪点121℃ flash point： 121℃分子式：C6H12N2O molecular formula： C6H12N2O 分子量128.18 molecular weight： 128.18 二、DMPU的化学性质 Chemical character of DMPU 其结构中由于羰基具有强烈的吸电子效应，因而它是一种非质子的极性溶剂，具有高沸点、高闪点、低熔点，在过滤、蒸馏、溶剂萃取等工艺操作中使用方便；毒性极低，对人体危害微不足道，也减少了对环境的污染；由于它具有极强的溶解性，能溶解有机物、无机物、树脂、聚合物等，并对各种试剂具有活化性质，还能与其它高沸点溶剂混溶；具有极好的稳定性，在热的强碱和酸性条件下都很稳定，还具有耐水性及对光、氧的稳定性。

We discussed the positive invariant set,the exsistence and the stability of the equilibrium by the stability theory of ordinary differential equation and the conditions for the global asymptotic stability of the disease-free equilibrium and the endemic equilibrium are obtained.

本文讨论了模型的正不变集，运用微分方程稳定性理论分析了模型平衡点的存在性及稳定性，得出了疾病消除平衡点和地方病平衡点的全局渐进稳定的充分条件。

In this paper, the boundedness and stability of solutions for a class of fourth order nonlinear differential equations are studied by using the method of Liapunov function.

本文利用Liapunov函数方法，研究了一类四阶非线性微分方程解的稳定性及有界性，得出了解的有界性及稳定性存在的充分条件。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。