碰撞

The main jobs of this dissertation are as following: Chapter one firstly describes the essential of collision detection problem, according which most the collision detection algorithms were classified into seven categories. Then a survey on hierarchy bounding volume, surface simplification and the particle swarm optimization is presented, which is the basis of the new frameworks.

本文的主要工作为：第一章概述了碰撞检测问题，把目前的碰撞检测算法分为八大类，主要介绍了与本文算法相关的层次包围盒技术和基于随机方法的碰撞检测技术，并详述了作为BASIC-PSO碰撞检测算法基础的粒子群优化搜索技术。

Then the formula of the impact force and contact time was induced,which the elastic coefficient of restitution was considered in contact time calculation.

根据赫兹接触模型和经典碰撞理论，并考虑返向器与螺母的固连关系，建立了滚珠与返向器碰撞接触的力学模型，导出了碰撞力公式，并在考虑弹性恢复系数的基础上推导出了碰撞接触时间公式。

By investigating the effect of all the factors, including particle size, density, elastic deformation coefficient, Hamaker constant, surface energy, yield limit and relative velocity, on the particle behavior in the process of collision, the rule of collision and agglomeration with the change of these factors is obtained in detail.

为考察包括颗粒的粒径、密度、弹性变形系数、Hamaker常数、表面能、屈服极限和碰撞初速度等众多因素对碰撞规律和团聚趋势的影响，本文采用"数值实验"方法，获得了碰撞力与范德华力的相互关系、碰撞弹性回复系数和团聚趋势随各参数的变化规律。

The simple calculation model of making collision analysis between train and bus at level crossing is given.

建立了列车与汽车在道口发生相撞事故时进行碰撞分析的简化计算模型；分析求解了在碰撞过程中汽车变形的位移、速度、加速度和碰撞力；对比分析了列车在不同速度下与汽车发生碰撞后各参数的变化情况。

The simulation result shows that door intrusion has greatly influence on child occupants' head and thoracic injuries. The risk of injuries is higher for the child who sits outboard nearside to the struck side than the non-struck side.

仿真结果表明：在侧碰撞中与碰撞速度有一定比例关系的车门侵入量对儿童乘员头部及胸部的损伤影响非常大，后排座椅靠近碰撞侧位置比非碰撞侧儿童乘员受损伤的风险要高。

In comparison of the two integral cross sections, it can be found that that the nonreactive process occurs more easily in lower collision energy.

通过反应性碰撞和非反应性碰撞积分截面的比较，发现在低能碰撞情况，非反应性碰撞更容易进行。

Within GVS, a terrain surface is represented internally as a mathematical structure and offers the user sophisticated "intersection" and "collision detection" capabilities including inquiries about height-of-surface, orientation of surface, range to intersections, information about which object instance in a scene may have been intersected, which "subobjects" have been intersected, even down to the individual user defined composition types (e.g., water, mud, metal) which have been intersected.

在GVS中，一个地形表面是作为数据结构在内部描述的，碰撞检测包含查询表面高度，表面方位，交集范围，关于场景中的哪个实体虚像应该已经被碰撞，哪个"subobjects"已经被碰撞，甚至到个别用户定义需要被碰撞的物体成分类型。

Afterwards, the crash process of the thin-walled structure is simulated to find the effect of the cross section, the thickness and the pre-deformation on the crash capacity, and the axial impact deformation of the circinal tube is analyzed in the theoretical way, the axial impact deformation of the square tube and subulate tube are analyzed by simulation.

最后本文建立了原DF_(8B)机车车体正面碰撞刚性墙的仿真模型，在分析碰撞结果后，对原DF_(8B)机车车体的底架和司机室结构进行了改进；并利用薄壁圆管和锥形结构设计了吸能装置，利用凸凹相见的防爬板设计了防爬装置；对安装了吸能装置和做出结构改进的耐碰撞DF_(8B)机车以10m/s和15m/s速度正面撞击刚性墙进行仿真，结果表明碰撞时吸收装置先于车体主结构破坏，吸收碰撞能量，其吸能能力达到了国外有关标准的要求。

Kalamaili suture zone is an important plate boundary in north Xinjiang, and there are plenty of Neopaleozoic volcanic rocks around itThese volcanic rocks are enriched in LILEs and relatively depleted in HFSEs, and they are also characterized by high Nb, Zr, TiO2 contents and Zr/Y, Nb/Y ratios, and depleted SrNd isotopesThe characteristics of these volcanic rocks suggest that they were produced in postcollisional periodThe postcollisional volcanic rocks around Kalamaili suture zone become younger from west to east, which indicates that this suture zone entered postcollisional period gradually from west to east, and reflects that the Kalamaili Ocean had been closed gradually from west to eastAs to the Kalamaili suture zone in postcollisional period, the lithosphere extended and thinned, and the asthenosphere materials upwelled and melted partially, and intensive mantle convection occurred, leading to a plenty of mantlederived magmas underplating the suture zoneThe lithospheric mantle metasomatized by fluid in subduction period melted partially under decompression and high temperature, the resulting melts contaminated the underplating asthenospheric materials, and the erupted lavas became the Neopaleozoic postcollisional volcanic rocks

卡拉麦里缝合带是北疆的一条重要界线，沿该带广泛发育晚古生代火山岩。这些火山岩具有LILE相对富集、HFSE相对亏损的特征，且具有较高的Nb、Zr、TiO2含量和Zr/Y、Nb/Y比值，SrNd同位素主要表现出亏损的特征。综合分析表明，这些火山岩形成于后碰撞期。对卡拉麦里缝合带而言，从西向东后碰撞火山岩的时代逐渐变新，表明该缝合带从西向东逐渐演化进入后碰撞期，这从侧面反映了卡拉麦里洋盆是从西向东逐渐关闭的。对卡拉麦里缝合带而言，在后碰撞期，岩石圈伸展减薄，软流圈地幔物质上涌并发生部分熔融，加上地幔对流作用强烈，使得缝合带下产生了大规模的幔源岩浆底垫；先前在洋壳消减期被流体交代提取过的岩石圈地幔也在低压高温下发生部分熔融，形成的熔体混染了底垫的软流圈物质并喷发，形成了晚古生代的后碰撞期火山岩。

Compared with existing methods, FCPF have the following characteristics:①Can improve precision of collision time and collision points but no more collision detection is needed;②Take into account of not only movement but also rotation of collided virtual objects;③Can find collision time and collision points among convex and/or concave polyhedrons.

与已有的一些方法相比，该方法具有以下特点：①不需要通过增加碰撞检测次数来提高碰撞时刻与碰撞点的求解精度，因而减少了碰撞检测的系统开销，提高了基于物理特性进行碰撞响应的实时性。

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。