四面体

The following is Ti-He which value is -6480.3 876eV. Ti-He(o2) had the more stable structure of four systems of Ti-He. The variety of volume before and after Geometry optimization proves this result. The population analysis also proves the interaction between helium atom and Ti was electrovalent bond.

利用Dmol3对钒、钛八面体和四面体团簇计算的结果表明，氦原子在金属钒四面体间隙的嵌入能比八面体间隙低，嵌入能为5eV；氦原子在金属钛八面体间隙的嵌入能比四面体间隙低，嵌入能为0.2eV。

This paper analyzes the cause of distortion of octahedron complexes and tetrahedron complexes and states the general methods to judge the distortion .

分析了八面体配合物和四面体配合物畸变的原因，给出了判断八面体配合物和四面体配合物畸变的一般方法：配合物是否发生畸变要看中心离子电子云是否对称分布，若对称分布，就具有规则的八面体或四面体构型，否则，将会发生变形。

ITQ-26 (INSTITUTO DE TECNOLOGIA QUIMICA number 26) is a new crystalline microporous material with a framework of tetrahedral atoms connected by atoms capable of bridging the tetrahedral atoms, the tetrahedral atom framework being defined by the interconnections between the tetrahedrally coordinated atoms in its framework.

ITQ-26(INSTITUTO DE TECNOLOGA QUMICA number 26)是新的结晶微孔材料，其具有通过能够桥联四面体原子的原子连接的四面体原子骨架，该四面体原子骨架通过其骨架中四面体配位原子之间的相互连接来界定。

ITQ-27 (INSTITUTO DE TECNOLOGíA QUíMICA number 27) is a new crystalline microporous material with a framework of tetrahedral atoms connected by atoms capable of bridging the tetrahedral atoms, the tetrahedral atom framework being defined by the interconnections between the tetrahedrally coordinated atoms in its framework.

ITQ-27(INSTITUTO DE TECNOLOGíA QUíMICA number27)是新型微孔晶体材料，其具有通过能够桥联四面体原子的原子连接的四面体原子骨架，该四面体原子骨架通过其骨架中的四面体配位原子之间的相互连接而确定。

The connecting of neighbour tetrahedran with common vertex angle forms M—O layer,and the connection of neighbour octahedran with common edge ...

偏岭石结构中近邻四面体与四面体共顶连接构成M—O层，八面体与八面体共棱或共面连接构成Al—O层；而四面体与八面体通过不规则的共顶连接构成近程层状结构。

The connecting of neighbour tetrahedra n wit h common vertex angle forms M—O layer,and the connection of neighbour o ctahedran with common edge or plane forms Al—O layer.

偏岭石结构中近邻四面体与四面体共顶连接构成M—O层，八面体与八面体共棱或共面连接构成Al—O层；而四面体与八面体通过不规则的共顶连接构成近程层状结构。

When we sum on all the tetrahedrons, and by means of a development of the determinant along the first line, we get a sum on determinants on triangles that must be either all oriented towards the interior of each tetrahedron, or all oriented towards the exterior.

当我们计算四面体的总数，通过沿着第一条起决定作用的线，我们获得了起决定作用角的总数，这些角既不是朝着四面体里面，也不是朝着四面体外面。

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。

The porous media model of software FLUENT was introduced to simulate the 2D flow through permeable tetrahedrons,and an experiment was conducted to verify the simulation;With the simulation,the influence of parameters such as Re、relative width b/B and relative length l/B on the protected length downstream of permeable tetrahedrons was studied.

本文首次尝试利用Fluent软件的介质模型对经过四面体透水框架群的水流进行了平面二维数值模拟，通过模型验证，多孔介质模型能较好地用于四面体透水框架群模拟；另外，通过数值计算，研究了Re、相对宽度b/B、相对长度l/B对四面体透水框架群下游保护长度的影响。

For wurtzite-type crystal, [Zn-S4]6- and [Zn-S4]6+ with different crystal positions distribute in the form of layers along c axis, where the two layers of tetrahedrons whirl 60 around c axis, so the crystal is mainly like hexagonal cone.

在纤锌矿型晶体中，[Zn-S_4]~(6-)和[Cd-S_4]~(6-)四面体沿c轴呈层状分布，上下两层四面体的结晶方位不同，两层四面体绕c轴旋转60°，晶体的结晶形貌为六方锥状。

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