上壳

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

The glass is fitted and fixed to an annular step part having been formed in the edge member.

玻璃壳安装和固定在形成在边缘构件内的环形台阶部分上。

Such as technical coatings on cutting and forming tools, construction materials, aviation / navigation / military equipment andothers, or very high quality decorative coatings on watchcases and watchbands, glass frames, leather bag and suitcase accessories, pen accessories and works of arts, in order to reach better or different characteristics (physical, chemical, mechanical, optical, color and so on).

在切削工具、模具、建筑材料、汽车、航空、航天和军事器材上进行工具镀镀膜，或者在表壳表带、眼镜架、高级箱包饰品、钢笔配件和工艺手饰上进行最高质量的半装饰性半工具性镀膜，以达到表面改善或改变的效果（物理、化学、机械、颜色和光泽等方面）。

Such as technical coatings on cutting and forming tools, construction materials, aviation / navigation / military equipment and others, or very high quality decorative coatings on watchcases and watchbands, glass frames, leather bag and suitcase accessories, pen accessories and works of arts, in order to reach better or different characteristics (physical, chemical, mechanical, optical, color and so on).

在切削工具，模具，建筑材料，汽车，航空，航天和军事器材上进行工具镀镀膜，或者在表壳表带，眼镜架，高级箱包饰品，钢笔配件和工艺手饰上进行最高质量的半装饰性半工具性镀膜，以达到表面改善或改变的效果(物理，化学，机械，颜色和光泽等方面)。

For the case of pH-induced micellization, as pH of the solutions decreases to below 4.6, micellar structure having insoluble complexes of PAA/PNiPAAm as the core and solvated HEC chains as the shell can be obtained due to hydrogen-bonding complexation between the proton-acceptors in PNiPAAm and the proton-donors in PAA.

首先发现pH诱导胶束形成的临界pH值在4.6附近，证实了胶束化机理是由于低pH下PAA接枝链上的质子给体与PNiPAAm支链上的质子受体间的氢键络合形成胶束的&核&，HEC不参与络合形成胶束的&壳&。

The shell of a snail is carried on its back, and its eyes are on long stems.

蜗牛的壳背在背上，它的眼睛长在长触须上。

The shell of a snail is carried on its back,and its eyes are on long stems.

蜗牛的壳背在背上，它的眼睛长在触须上。

Mr. Flanagan says multiply those losses by today's commodity prices and you get an idea of how much money Shell is losing on just that one rig.

弗拉纳根说，把这些数字乘上今天的石油和天然气价格，你就知道壳牌石油公司仅仅在一座平台上的损失了。

Note that not all brake discs are fixed on the hub with a screw or nut

请用刹车固定制（详见55图P41页）注意所有的刹车碟不一定是用一粒螺丝上紧在车的车壳轴上。

Production: first eggs cooked, let cool after the peeled and cut with a knife to the egg, and then remove the egg yolk; and then cut into the woods at the end of half an egg-shaped, to stand on the plate; the salad dressing and after the egg yolk mix, then put into the egg-ri, the last raisins and fruit will be placed on the fait accompli.

制作：先将鸡蛋煮熟，放凉后去壳，并用刀子把蛋切开，然后把蛋黄取出；再把半个蛋底切成林子状，让其站在盘子上；把沙拉酱和蛋黄拌匀后，装入蛋林里，最后将葡萄干和果料放上即成。

The concept of equivalent rotationally rigidity is offered and the formula of rotationally rigidity is obtained.

主要做了如下几个方面的工作：对伸臂位于顶部的单层框架—筒体模型进行分析，提出了等效转动约束的概念和转动约束刚度的表达式。

Male cats normally do not need aftercare with the exception of the night after the anesthetic.

男猫通常不需要善后除了晚上的麻醉。