3 ) a 3 - d geometry and finite element model of the assembly of the obturator of the breech mechanism is established . quasi - static and dynamic finite element analysis of stiffness , strength and obturating performance of the obturator of the breech mechanism is carried out , based on elastoplastic theory and multi - body contact algorithm , and the simulation results coincide with experimental results , further , th e effect of friction factor on its obturating performance is investigated 建立了炮闩闭气结构的三维装配体几何实体模型和有限元模型，对炮闩闭气结构刚强度和闭气性能进行了准静态及动态多体接触弹塑性有限元分析，分析结果与试验结果相吻合，进一步研究了摩擦系数对其闭气性能的影响。
The denifition of cwml brought xml into the online courseware building area , xml is easy for information taken out and self - descripted , cwml solved the issues such as the form of courseware is obturated , the information is hard to take our and reform . at th 使用authoringsystem来进行cwml网上课件的制作，能够高效率、迅速地完成能够重新组合利用的课件形式，很好地支持v阳bservice技术环境下的资源查询和绑定需求，是在进行分布式网上课件点播系统建设的最佳选择之一。
With the development of information techonology , especially the popularizing of internet , the obturate of databases of institutions with pivotal canonical information turns to a serious problem . this encumbers the development of information tech effectively using of information and consistency of especially information between institutions 随着信息技术的发展，特别是互联网应用的推广，关键、权威机构的数据库信息封闭性已成为严重的问题，大大地影响了信息化的发展、信息有效利用和行业(或机构)关键信息的一致性。
Graphical user interfaces are developed to be convenient for implementing of parameterized model and debugging of program parameters . program of optimization based on ga is designed to optimize obturating performance of the obturator of the breech mechanism , further , the effect of control parameters of ga and friction factor on the optimal structure is studied 开发了实施参数化建模和程序参数调试的界面，编制了遗传算法优化程序，对炮闩闭气结构进行了闭气性能优化，并研究了遗传算法运行的控制参数对优化结果的影响以及摩擦系数对最优结构形式的影响。
According to the requirement of the obturated deformation and based on analyzing cad designing method of hydraulic press before , a new designing method aiming at practical comercialization , cad parametric designing method of obturated extrusion hydraulic press , has been developed on the platform of ugii software 本文根据闭塞成形工艺的要求，在总结分析了以往液压机本体cad设计方法的基础上，以ug为软件开发平台，应用现代先进的设计理论与方法，以实用商业化为目标，研究了一种全新的液压机设计方法? ?闭塞成形液压机本体cad参数化设计方法。
Success in optimizing the obturating performance of the obturator of the breech mechanism shows that the method and technology for optimal design of nonlinear multi - component structural system with contact put forward in this thesis is effective and practical . structural optimization problems that are difficult to solve through the optimization method available in the universal cae software can be accomplished by means of this method 对炮闩闭气结构闭气性能优化的成功说明了本文提出的对存在接触关系的多构件非线性结构(装配体)系统进行优化设计的方法和技术途径具有实用价值，可以解决在通用cae软件中现有优化算法难以解决的结构优化问题。
Firstly , fourier descriptor used to describe the object ' s shape is introduced to the extraction of feature of apple ' s shape . the boundary of apple is an obturated curve , distance between boundary point and centroid r ( k ) " is used as a function to express the 2 - d boundary in spatial domain . the fourier transform coefficients of the discrete sequences f ( h ) are spectrum values in frequency domain , and they compose feature parameters of shape 首次将图像分析理论中对形状的傅立叶描述方法引入到对苹果形状的特征提取中，果实边界是一条封闭曲线，用边界点到形心之间的距离长度r ( l )作为空域中对二维曲线的表达函数，离散的函数值序列r ( k ) ~ l的离散傅立叶变换系数f ( h )就是频域中得到的频谱值，可作为形状的特征参数。
Comparison of stiffness , strength and obturating performance of the initial obturator of the breech mechanism with those of the optimized one is made , which indicates that the stress concentration that leads to fatigue failure in the optimized structure is eliminated . the flexibility of the optimized obturator of the breech mechanism is considerably increased and its obturating performance is substantially improved 对优化前后炮闩闭气结构刚强度和闭气性能进行了对比，优化后的结构应力集中问题得到了有效控制，消除了潜在的疲劳源，结构的柔性得到很大程度的提高，闭气性能有了明显改善，实现了优化的目的。
