基本四面体

Introduced the makeup and analysis procedure of ANSYS software, and the calculating precision difference between tetrahedron element and hexahedron element are discussed, and thorough research are made to the hexahedron mesh method.

介绍了ANSYS程序结构及其分析的基本过程，重点讨论了ANSYS的模型建立和网格划分，初步分析了四面体和六面体单元对计算精度的影响，并对六面体网格划分方法进行了深入的研究。

The basic process of tetrahedral octree spatial decomposition for using directly in finite element analysis is described.

然后在此基础上详细论述了正四面体八叉树法划分空间、直接生成四面体网络单元的基本过程。

The two-dimensional structural units (such as silicon-oxygen tetrahedral sheet, octahedral sheet), interlayer space are assembled according to the sphere close packing manner, and the close packing layers parallel to {0001}. There are several mechanisms to release the difference in size while the silicon-oxygen tetrahedral sheet and octahedral sheet assemble the TO and TOT-type structural layers. The two types of structural layers with different interlayer space fitted together in six kinds of assembling modes and formed six kinds of crystal layers. The combinatorics analysis of the two-dimensional structural units revealed that there may be 28 kinds of TOT type interstradified minerals in six kinds of polysomatic assembling modes of interatradified structure. The structural layer is symmetrical for octahedron sheet in the structure of interstratified minerals and shows polarity characteristics.

结果表明，不同二维结构单元体（包括硅氧四面体片、八面体片、层间域的构筑基本符合球体紧密堆积原理，紧密堆积层平行{0001}；四面体片与八面体片构筑TO和TOT结构层时采取多种机制消除二者在二维尺寸上的差异；两种模式的结构层与不同类型的层间物组装形成六种组装模式的晶层；并通过二维结构单元体的组合规律的分析，计算出可能存在的28种TOT型间层结构，它们分属于6种间层结构多体性组装模式；间层结构中，结构层对于八面体片是不对称的，并在属性上表现出极性特征；间层矿物的晶层类型可用6种多体性组装模式加以表达。

For the cement, the surface hydration is the primary process at the initial stage, the kaolin disorganizes and gets into the solution in the form of the silicate tetrahedron and aluminate tetrahedron at the induce stage; the silicon-aluminum tetrahedron network structure is formed at the accelerate stage; the unti-network structure is formed and the rate of heat evolution falls at the decelerate stage; the reaction finished ultimately at the stable stage.

但其水化机理与传统的硅酸盐水泥不同：初始期主要是表面水化，诱导期是高岭土解体并以硅氧四面和铝氧四面体的形式进入液相；加速期形成硅铝四面体网络结构；减速期网络基本形成，水化放热速率降低；稳定期反应速率很低，网络结构趋于稳定。

Cutting process of soft tissue and organs is very important in virtual surgery simulation. Tetrahedron is widely used to construct the geometric model of virtual organs. Efficient methods must be developed to split or merge tetrahedrons in order to adapt to topology changes during cutting process. The main parts of this thesis are the two chapters on "Reconstruction of Tetrahedrons" and "Stability of Tetrahedrons".Main research work I have done is listed as follows:1 Reconstruction of Tetrahedrons.

人体软组织及器官的切割仿真是虚拟手术仿真的重要组成部分，软组织及器官的几何模型普遍采用四面体模型，切割的同时，软组织及器官的拓扑结构发生变化，模型中的部分四面体基元必须能够通过分裂或合并以适应上述变化，医学数据在三维场景中的交互和可视化是手术仿真的基本要求，因此，第二章&四面体重构&以及第三章&四面体单元稳定性&是本文重点讨论的两个部分。

Its rule of change was obtained. On the basis of other studies, the flocculation kinetics and flocs structure was studied. By making some assumptions, collision frequency were presented. Then the the flocculation kinetics model was established through population balance equation. Comparison of experimental data and modeling results indicate that there are the same trend between the two. So the model can predict flocs number and size during flocculation of Yellow River's loess particles without using empirical parameters. The TEM and SEM were used to obsever flocs in the study of floc structure. The flocculation was divided as flocculi, floc and floc aggregate. The flocs structure model was established by assumption that particles position in floc accords with tetrahedron. The fractal dimension of model and experimental flocs was found to be coincident. So the model can reflect the structure of flocs formed in flocculation of Yellow River's loess particles by macromolecule flocculant at a certain extent.

最后，本文还对絮凝动力学和絮体结构进行了研究，在前人研究的基础上，针对高分子絮凝黄河泥沙，对絮凝过程作了一些符合试验条件的假设，建立了颗粒碰撞频率表达式，应用了颗粒数量平衡方程，从而建立了絮凝过程的动力学生长模型，模型计算结果与试验数据对比表明，二者趋势一致，在没有使用经验参数的情况下基本上能够描述黄河泥沙絮凝过程中絮体数量和尺寸分布的变化过程；对絮体结构的研究中，应用扫描电子显微镜和透射电子显微镜对絮体进行了观察，将絮体分为絮粒、絮团和絮网三个不同的生长阶段，通过假设颗粒结合位置符合正四面体，建立了絮体结构模型，计算得到的模型絮体分形维数基本与试验中的实际絮体相符，在一定程度上能眵反映高分子絮凝黄河泥沙生成的絮体结构。

Its rule of change was obtained.On the basis of other studies,the flocculation kinetics and floes structure was studied. By making some assumptions, collision frequency were presented.Then the the flocculation kinetics model was established through population balance equation. Comparison of experimental data and modeling results indicate that there are the same trend between the two. So the model can predict floes number and size during flocculation of Yellow River's loess particles without using empirical parameters.The TEM and SEM were used to obsever floes in the study of floe structure.The flocculation was divided as flocculi,floc and floe aggregate.The floes structure model was established by assumption that particles position in floe accords with tetrahedron.The fractal dimension of model and experimental floes was found to be coincidentSo the model can reflect the structure of flocs formed in flocculation of Yellow River's loess particles by macromolecule flocculant at a certain extent

最后，本文还对絮凝动力学和絮体结构进行了研究，在前人研究的基础上，针对高分子絮凝黄河泥沙，对絮凝过程作了一些符合试验条件的假设，建立了颗粒碰撞频率表达式，应用了颗粒数量平衡方程，从而建立了絮凝过程的动力学生长模型，模型计算结果与试验数据对比表明，二者趋势一致，在没有使用经验参数的情况下基本上能够描述黄河泥沙絮凝过程中絮体数量和尺寸分布的变化过程；对絮体结构的研究中，应用扫描电子显微镜和透射电子显微镜对絮体进行了观察，将絮体分为絮粒、絮团和絮网三个不同的生长阶段，通过假设颗粒结合位置符西安建筑科技大学博士学位论文合正四面体，建立了絮体结构模型，计算得到的模型絮体分形维数基本与试验中的实际絮体相符，在一定程度上能够反映高分子絮凝黄河泥沙生成的絮体结构。

Based on analysis of solution structures, growth units of CMTC crystal are determined to be formed by HgS〓 and CdN〓 tetrahedra structural units linked by -S=C=N- bond bridges and the growth units vary in dimensions with the supersaturation of growth solutions.

由溶液结构的测试结果推断出CMTC晶体的生长基元是以HgS〓和CdN〓配位四面体为基本单元，经-S＝C＝N-桥连接组成的网络结构，并且随溶液过饱和度的变化生长基元的维度也随之改变。

In GeS2-Ga2S3 glasses, the basic structural units forming the backbone ofthe network are GeS4/2 and GaS4/2 tetrahedra which are connected through a bridging sulfur to form a three-dimensional network.

在GeS_2-Ga_2S_3玻璃中，形成网络骨架的基本结构单元是GeS_(4／2)和GaS_(4／2)四面体，它们通过桥硫连接成三维空间网络。

Delaunay method for generation of 3D unstructured grids is analyzed and the tetrahedrization approaches are presented.

对生成三维非结构化网格的D e launay方法进行了分析，给出四面体网格生成的基本步骤。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了