查询词典 TOPICS

The linear system optimum control theory distributes one of parameter systembasic topics,in domains and so on aerospace,national defense,finance,communicationhas the widespread application prospect.simultaneously, because the research tech-nique involves to foundation mathematics theories and so on the functional analysis,analysis situs,geometry, algebra.

线性系统的最优控制理论是分布参数系统的基本课题之一，在航空航天、国防、金融、通讯等领域有着广泛的应用前景。同时，由于研究手法涉及到泛函分析、拓扑学、几何学、代数学等基础数学理论。

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。

Based what mentioned before, in the background of Chinese traditional culture and poetic theory ,this thesis does an overall and precise analysis and research on five hot poetic topics: poetic prophecy, attitude towards being an official and being an anchoret, The Resurgence Of Tang Dynasty, qi xiang, philosophical art in notes written in Song Dynasty.

本文即立足于此，在中国传统文化及诗学理论的大背景下，对宋人笔记中诗谶、仕隐心态、《大唐中兴颂》、气象、理趣等五个诗学讨论热点，作了较为全面和细致的分析和研究。

When meeting someone in a Western business setting, conversation usually remains focused on business matters and business topics. Family andor personal matters are not brought up, especially the first time you meet.

当在西方的商务场合中会见某人时，对话通常围绕着一些商业问题或商业话题，而不会涉及家庭和个人问题，特别是第一次见面时。

This is probably one of the biggest topics in bass fishing that an angler should learn more about.

这大概是一个最大的课题，一个在低音捕鱼钓鱼要多些了解。

Shortly before Edward's death, Cranmer presented a doctrinal statement consisting of forty - two topics, or articles, as the last of his major contributions to the development of Anglicanism.

不久之前，爱德华死亡，克兰麦提出了理论上的声明组成的42主题，或文章，作为最后他的重大贡献的发展Anglicanism 。

We discuss various topics animatedly in English in our dorm every night.

例2：我们+每天晚上+在宿舍里+用英语+热烈地讨论+各种话题。

Biological control has become hot topics on banana anthracnose , which is one of the most important post-harvest diseases on banana.

香蕉炭疽病是香蕉采后一种重要病害，生物防治香蕉炭疽病成为研究的热点。

The topics of anthropocentrism, natural rights and natural value of environmental ethics are discussed.

分析探讨了环境伦理学中"人类中心主义"、"自然权利"和"自然价值"等共同关注的话题，阐明了环境伦理学的理论特质。

Then the dissertation analyzes the traditional sports anthropologically and explores some topics in study of traditional sport, and the relation among human adaptability, social development and sport.

在此基础上，对传统体育进行人类学分析，探讨传统体育研究中出现的一些问题，并且对人类的适应性与社会发展和体育发展这三者的关系进行了探讨。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。