有保持力的

A washer has a body having an axis and provided with a first bearing face surface located at one axial side and adapted to cooperate with a nut, a second bearing face surface located at an opposite axial side and adapted to cooperate with an object, at least one third turning resistant surface adapted to cooperate with a thread of the bolt, the body having at least one resistive point arranged so that when the nut is turned and turns the bolt the body of the washer stops the bolt from turning and thereby the nut creates a pull on the bolt which elongates the bolt in an axial direction and applies to the body of the washer an axial force which overcomes the at least one resistive point so that a portion of the body of the washer is allowed to be pulled axially when the bolt elongates.

一种放在螺帽与物体之间的垫圈，螺帽与螺栓螺纹连接，螺栓插入在包括两个装配的部件的物体内，垫圈具有主体，和设有第一支承面表面，位于一个轴向侧面和与螺帽配合，第二支承面表面，位于相对的轴向侧面和与物体配合，以及至少一个第三转动阻力表面，与螺栓的螺纹配合，从而使螺帽以给定的扭矩在一个方向转动同时垫圈的主体沿相对方向接收给定的力时，仅有螺帽转动，以紧固或松开螺栓，而垫圈的主体和螺栓保持静止。

To make a comprehensive view of metapopulation researches, we folly analyze and summarize the present concepts, theories and models of metapopulation in this paper, which primarily includes the dynamical models and simulation approaches of single and competitive metapopulations. Based on the Levin's patch occupant model, the center framework of metapopulation researches, primary principles and mechanisms are discussed. First, Levins rule: the fraction of empty patch will remain constant with habitat destruction as long as metapopulation survives. This rule implies that empty patches have determinant effects on persistence and conservation. Second. Allee effect of metapopulation is incurred by establishing difficulties and dispersal costs, which is important to the studies of reserve area and the minimum available metapopulation size. Third, we analyze the rescue effect that immigrants can reduce the extinction risk of the presented local population. Rescue effect can leads to the improvement of metapopulation sustainability and the decrease of fraction of empty patches. Fourth, the coexistence mechanism of two competing metapopulation is discussed, which suggests that competition-colonization trade off may be prevalent in competing systems. Finally, extinction debt ob tamed from coexistence mechanism is given, which depicts the lost of species richness in the future for the current habitat destruction. After theoretical discussion, we present two popular simulated approaches in metapopulations: probability transition model and stochastic process model.

为了能总观集合种群进展的全局并开展进一步的工作，首先对集合种群的已有概念、理论和模型做了全面的分析和总结；其次对集合种群的发展和概念进行了探讨，以集合种群模型的中心框架：Levins的斑块占据模型为基础，展开对其它原理、效应和机制的探讨；主要包括了Levins原理，即当生境进到破坏时，空斑块比例在集合种群灭绝前保持不变，然后还分析了Allee效应（集合种群的Allee效应主要是由于建群困难和扩散损失造成的）；第三，分析了援救效应：迁人个体可以降低斑块中现有局域种群的灭绝风险，援救效应会增强集合种群的生存力，使空斑块比例下降第四，探讨了两竞争集合种群的共存机制，即竞争－侵占妥协，其共存机制为空间生境中物种共存提供了有力的理论解释。

Reformulates our country civil retrial system, we may do following several aspects:We should overcome the absolute wrong tendencies guiding ideology which is" right wrongs by seeking truth from facts," Reaffirm civil purposes, ensure the exercise of the right of the parties, establish and maintain effective balance between correcting mistakes judgment and stability、 authority, achieve the balance of relief to flaw judgment and res judicata, coordinate social justice and order, which should be new guiding ideas of civil retrial system.

重构我国的民事审制度，可以从以下几个方面入手：我们应当克服将&实事求是、有错必纠&指导思想绝对化的错误倾向，将&重新确认民事诉讼目的，确保当事人诉讼权利的行使，树立兼顾纠正错误裁判与保持生效裁判稳定性、权威性，以实现判决既判力与判决瑕疵之救济的平衡，使社会正义与秩序相协调&确定为民事再审程序的新的指导思想。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。