四面体

Tetrahedron can be formed with four sequence and non-coplanar points in space,and any points in it can be represented by barycentric coordinate system with space affine transform.

给定空间不共面的四个有序数据点，可以形成一个四面体。

Here is the method to get the volume from the boundary defined by a set of oriented faces defined by sets of triangles that can be oriented: if we imagine that the volumetric object is decomposed into a set of tetrahedrons, it is necessary just to calculate the sum of volumes of each tetrahedron.

用一些有方向角的集合定义一些有方向的面，再用面的集合定义边界，有一种方法可以从这些边界中得到体积。如果我们设想有体积的对象被分解为四面体的集，那么只要计算四面体的体积总和就可以了。

The revetment is made up of many single permeable tetrahedrons,and has much gap,so the group of permeable tetrahedrons can be treat as the porous media with large porosity.

四面体透水框架群是由很多单个四面体框架抛投而成，具有很大的空隙，因而，可以将框架群看成由很多框架杆件和大的孔隙组成的大孔隙率多孔介质。

Two ways to measure stability of tetrahedrons will be introduced. An earlier method to improve tetrahedron stability, the Snap Method, will be briefly discussed. Then techniques used in Delaunay. triangulation to deal with degenerated elements will bethoroughly investigated.

本文引入了两种单元质量的描述方法，简单介绍了已有的提高四面体稳定性方法之一—投射法；然后介绍了Delaunay方法中使用较广泛的逐点插入法的核心思想，将Delaunay网格构造法中处理退化单元的方法；删除法和换面法，改造后应用于四面体稳定性的提高上。

Titanium silicalite molecular sieves are a type of heteroelements-containing molecular sieves which are comprised of Ti-0 tetrahedrons and S:-0 tetrahedrons.

钛硅分子筛是由钛氧四面体和硅氧四面体构成的一类杂原子分子筛，它是将钛引入全硅分子筛骨架的一种新型催化材料。

Inosilicate: Any of a class of inorganic compounds that have structures characterized by silicate tetrahedrons (a central silicon atom surrounded by four oxygen atoms at the corners of a tetrahedron) arranged in chains .

链状硅酸盐：旧称偏硅酸盐。由硅酸盐四面体(四面体角上的四个氧原子围绕着一个中心硅原子)排成链状结构的化合物。

Inosilicate: Any of a class of inorganic compounds that have structures characterize d by silicate tetrahedrons (a central silicon atom surrounded by four oxygen atoms at the corners of a tetrahedron) arranged in chains.

链状硅酸盐：旧称偏硅酸盐。由硅酸盐四面体(四面体角上的四个氧原子围绕着一个中心硅原子)排成链状结构的化合物。

If two tetrahedra coincide after suitable reflection and rotation, we regard them to

的四面体可以有多少个同的形？（如果个四面体经适当的反射和旋转

Each tetrahedron shares two of its oxygens with neighboring tetrahedra.

每个四面体都有两个氧原子是与其相邻的两个四面体共用的。

We obtain three classes of polyhedra which have high symmetry.

本文将Goldberg在正十二面体上构筑多面体的方法推广到其它柏拉图多面体上，分别得到了三类具有较高对称性的多面体：属于四面体群的正四面体类和属于八面体群的正六面体类、正八面体类。

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