材料

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。

According to the Vegard's law and density functional theory of quantum mechanics, the lattice match conditions of Boron-contained arsenide and antimonide quaternary materials have been deduced, the bandgap properties of such quaternary materials have been theoretically analyzed, and the bandgap bowing parameters of all ternary compounds included have been theoretically calculated.

依据维加德定理和量子力学中的密度泛函理论计算出含硼砷化合物和含硼锑化合物四元系材料与GaAs、Si晶格匹配的条件及其带隙性质，同时计算出上述四元系材料所含三元系材料的能带弯曲参数，进而推导出BInGaAs、BInAlAs、BGaAsSb和BGaPSb四元系材料的发光波长与硼元素并入比例的关系。

New bone formation was observed to be increasing significamly in both DCN bone cements and DC bone cements with the passage of time. By the end of 24 weeks, new bone had bridged the gap between the proximal and distal fragments in DCN bone cements and DC bone cements. By histomorphological detection in DCN bone cements, Abundant of chondral and new bone islands were seen at the site of defects 4 weeks after the operation and a number of new bones formed and enlarged by both enchondral ossification and appositional formation by the 8th weeks.

研究发现，DCN骨水泥植入4周大量间充质细胞分化，在材料与骨端之间出现一层软骨细胞，软骨细胞继续增生并向编织骨分化；8周材料降解的同时，小梁骨出现；12周新骨长入材料并已经基本替代完成，形成初步骨性连接；24周骨缺损完成骨性连接，新骨进行结构改建，材料内部形态结构明显变化。

It mainly covers the basic components, technological nature and function, quality control approaches and usage approaches of commonly used architecture materials in engineering constructions such as calcareousness, gesso, concrete, beton, steel, limber, asphaltum, decoration materials, heat preservation, adiabatic and waterproof materials.

该课程主要讲述工程建设活动中常用建筑材料（石灰、石膏、水泥、混凝土、砂浆、钢材、木材、沥青、装饰材料、保温绝热及防水材料等）的基本组成、技术性能、质量检验方法和使用方法，并且讲述根据工程建设项目的特点和要求，合理选择和正确使用建筑材料的基本方法。

When designing multi-layer packaging, barrier protection may be provided from layers in addition to the barrier layer.

设计多层包装材料的时候，材料的阻隔保护功能不仅来自阻隔材料层本身，还可能同时来自其他的几层材料。

This thesis is composed of two parts:(1) Preparation and properties of organic functional materials including electroluminescence materials, electrical bistable materials and rectification materials.(2) Study of organic crystal structure.

本文主要由两部分构成：(1)有机功能材料的制备及性质，包括有机发光材料，有机电双稳材料以及有机电整流材料；(2)有机晶体的结构研究。

The replica material used in this study is Polydimethylsiloxane. The enlargement of replica compared to original size is 2.34%. Since PDMS is transparent, a layer of metal should be sputtered on its surface to measure optical characteristic, however the accuracy will be affected by the metal coated. The result assumes that Sternocera aquisignata, Chrysochroa rajah and Catoxantha opulenta may have one-dimensional photonic crystal structure. The fabrication of quasi-structure with elytra from Buprestid can promote the applications in the field of photonic structure and optical components.

经PDMS翻印的结果，最小仅增加原始尺寸的2.34%，翻印结果良好，但因翻印结果需镀上一层材料，使得镀上的材料严重影响结构的反射率，造成结构不同反射率也类似的情形，将结构刻画在不需镀金的材料上，将可防止镀上材料影响反射率的问题，并将所制成之结构用於防伪、光子结构研究和光学元件上。

Twenty varieties or materials of tomato with different resistance were used for experiment. Through testing the reaction condition and pH of extract of POD and PPO, identifying the genetic relationship of twenty varieties by POD isozyme and testing the biochemical indexes of resistance to ToMV, the main results were showed as follows:1. Classification of resistance: According to the campestral resistance to ToMV and the analysis experimental data ,the resistance of twenty varieties were divided into three kinds:z(1)resistant variety, including Zhong-za No9. Zao Hong-bao.

本试验以20个番茄品种或材料为试材，研究了过氧化物酶、多酚氧化酶酶液提取及反应适宜条件；应用POD同工酶对20个番茄材料进行亲缘关系的鉴定；对20份材料苗期室内接种ToMV后进行抗病性鉴定以及接种两周后所有材料POD、PPO、苯丙氨酸解氨酶的活性变化的研究，得出以下结论： 1。

We produced Epoxy Floor Materials, carborundum abrasion-resistant material, waterproof building materials, building insulation materials received by the overwhelming majority of the construction industry.

我们生产的环氧地坪材料，金刚砂耐磨材料，建筑防水材料，建筑保温材料受到广大建筑业的好评。

The components of the amianthine cat whisker-free friction material of the invention mainly contain binding agent, reinforcing material, frictional property regulating reagent, cat whisker material and fillings, and contain no asbestos fiber, the cat whisker material is adopted to be filled in the friction material to improve the wear resistance of the friction material, protect the environment, and prolong the service life of an arrester gland.

本发明的无石棉晶须摩擦材料其组成为：主要含有粘结剂、增强材料、摩擦性能调节剂、晶须材料及填料，不含有石棉纤维，采用晶须填充在摩擦材料中以提高其耐磨性、保护环境、延长制动器衬片的使用寿命。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。