周期

This main approach is also coincidence degree theory. Moreover, when the time scale T is chosen as the sets of real or integer numbers, the existence of periodic solutions for its differential or difference equation are obtained respectively.

若分别选取时标T为实数集或整数集时，则分别得到它的微分方程或差分方程周期解的存在性，这就避免了对这些生态系统的微分和差分方程周期解的存在性分别进行讨论。

The existence of periodic solutions for a class of impulsive differential equations of mixed type is studied by constructing periodic sequence solutions of difference equations.

通过构造差分方程的周期序列解，研究了一类混合型脉冲微分方程周期解的存在性。

What differ from that of the researchers in the past is the consideration of the direction of Hopf bifurcation with Dirichlet boundary condition , that is, the conditions when the Hopf bifurcation periodic solutions are orbitally asymptotically stable with asymptotic phase.Our basic idea come from the results given by Tang[30]. We adopt the method used by Hassard in the Hopf bifurcation theorem in [24], which is to judge the existence and the direction of Hopf bifurcation, and the stability of the Hopf bifurcation periodic solutions.

与以前的研究者不同的是，本文不仅讨论了在Dirichlet边界条件下系统的Hopf分支在以扩散系数为分支参数的情况下的存在性和分支周期解的空间非齐次性，而且更多的关注了系统在Dirichlet边界条件下Hopf分支解的稳定性及Hopf分支的方向，也即系统定态解在何种条件下，当分支参数如何变化时产生Hopf分支且分支周期解是带渐近位相轨道渐近稳定的。

The boundary conditions are assumed to be either the Dirichlet condition or linear Robin conditions.

在第一章，我们应用上、下解方法，bootstrap技巧和Schauder不动点定理考察如下三类周期反应扩散方程组的周期稳态解的存在性和一般的时变解的渐近性态：（1）拟单增系统；（2）混拟单调系统；（3）一个非拟单调2-系统，其边界条件是Dirichlet条件或线性Robin条件。

In Chapter 1, we use the upper and lower solutions method, the bootstrap technique and the Schauder fixed point theorem to investigate the existence of periodic solutions and the asymptotic behavior of general time-dependent solutions for periodic reaction-diffusion systems of the following three types:(1) Quasimonotone nondecreasing system;(2) Mixed quasimonotone system;(3) A nonquasimonotone 2-system. The boundary conditions are assumed to be either the Dirichlet condition or linear Robin conditions.

在第一章，我们应用上、下解方法，bootstrap技巧和Schauder不动点定理考察如下三类周期反应扩散方程组的周期稳态解的存在性和一般的时变解的渐近性态：（1）拟单增系统；（2）混拟单调系统；（3）一个非拟单调2-系统，其边界条件是Dirichlet条件或线性Robin条件。

Theorem （convergence Theorem , Dirichlet Condition

定理（收敛定理，狄利克雷充分条件）设是周期为的周期函数，如果它满足

Liquid crystal display;life cycle assessment;impact assessment of life cycle

液晶显示器；生命周期评价；生命周期影响评价

This traditional building method has many shortcomings: dissever factitiously some process and nobody is responsible for connection sections, many works distributed by different departments lose managing and controlling, and many overhead costs become virtual un-control cost; Confirming the overall budget management emphases through lifecycle method, it"s unfit for enterprise group which deals in different fields, because these deals in different fields can effect each other, and make it"s hard to distinguish the enterprise groups lifecycle.

这种传统的构建方法有许多不足之处，如：将一些作业或流程人为地割裂开来，使得它们的接口部位无人负责，众多分布于不同部门却相互联系的作业因此失去管理和控制，与此相关的众多原本可控的间接成本因此而成为事实上的不可控成本；通过生命周期法确定企业预算管理的重点，对于多元化经营的企业集团，由于各个产业之间的互动关系，往往有生命周期淡化的特点，这种方法就显得不是十分适宜。

As a result,the AVNERP could n ot be measured in any dog. AV conduction curve showed significant changes before and after the administration of Metoprolol at equivalent basic cycle length,AFR P also showed significant prolongation.

分 析发现静注美托洛尔前后各个基础周期条件下，8只犬AVNERP均不能测出；相同基础周期条件下，美托洛尔用药前后房室传导曲线有明显变化，AFRP也明显延长(P＜0.05)。

With perturbation shifting circumferentially step by step, the subsonic flows around slender bodies of revolution vary gradually in manner of single periodicity,while the supersonic flows vary gradually in manner of double periodicity.

由于临界周向位置的存在，随微小扰动沿周向逐渐移动，细长旋成体大攻角亚音速绕流呈现为"单周期、连续变化"规律，而超音速绕流则呈现为"双周期、连续变化"规律。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失