四面体

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。

There are also two types of IPTligands in crystal 2. With two bidentate carboxylates, one acts as bridging ligandconnecting neighboring 〓 tetrahedral core along c axia to form ladderlike long chain.

且间苯二甲酸根配体可以分为两类：第一类配体中每个羧酸根连接四核锌四面体结构中的四条边并沿c轴方向连接邻近的四面体结构单元形成梯形长链。

Results show that protons are liberated by dehydration or dehydroxylation after calcination at 500℃. These protons disrupt the silicon-oxygen-aluminium bridges where there are Al substitutions in the tetrahedral sheet of the montmorillonite. Some of silicon-oxygen and aluminum-oxygen tetrahedral invert to react with the pillaring agents and yield covalent bonds which firmly fix the pillars to the host clay. The Al-MMT are thermally and hydrothermally stable up to 700℃.

经过500℃高温焙烧后，交联剂经脱水或脱羟基释放出质子攻击蒙脱土四面体层中Si-O-Al四键，硅氧四面体和铝氧四面体发生翻转，与交联剂发生反应生成共价键，形成稳定的层柱黏土材料，在700℃高温下，Al-MMT材料不仅具有较好的热稳定性，而且具有较好的水热稳定性。

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。

The conception of the edge element was firstly proposed by Whitney in 1957. At the beginning of 1980\'s, Bossavit and Verite put it to practical application to three-dimensional eddy-current problems. In 1987, Barton and Cendes applied the tetrahedral element to three-dimensional magnetic calculation.

棱边元的构想，最早由Whitney在1957年提出。80年代初期，Bossavit和Verite将四面体棱边元应用于三维涡流问题，1987年，Barton和Cendes将四面体棱边元首次应用于三维磁场计算揭开了基于棱边的有限元方法在电磁问题中应用的序幕。

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。

For comp ound 7, the cage is consisted by six MoO〓 and four PO〓. The six MoO〓 octahedrons have consisted to the loop structure, the there PO〓 tetra hedron become triangle and the other one lies the centre. The one oxygen of two MoO〓 octahedron is coordinated to Mn atom which linked the other cage like this cag e and this Mn have six ligands.

在化合物7中，每一个笼由6个MoO〓八面体和4个PO〓四面体构成，6个MoO〓八面体构成环，四个PO〓四面体形成一个三角形在其上面，4个P和6个Mo具有C〓的对称性，每二个MoO〓八面体提供一个O原子与Mn原子配位，这个Mn原子再与相同的这样的笼相连，形成一个中间细两端粗的形状，这个Mn原子是6配位的，每一个这样的笼再通过一个Mn原子连接起来，形成二维的网状结构，而这个Mn原子是五配位的。

Upon the addition of CdS into the GeS2-Ga2S3 system, the number of the metal-metal bonds and edge-shared GaS4/2 tetrahedra decreases, resulting in the formation of corner-shared tetrahedra with non-bridging sulfurs.

随着CdS逐渐加入到GeS_2-Ga_2S_3玻璃中，金属-金属键和共边连接的GaS_(4／2)四面体逐渐减少，导致相应共角连接四面体和非桥硫的出现和增加。

The quality and quantity of the newly generated tetrahedrons will greatly affect the subsequent computations.

2四面体单元稳定性的提高四面体重构后新产生的单元的数量和质量将直接影响到模型后续计算。

Two of the oxygen atoms of each tetrahedron are shared with other tetrahedrons, forming a chain that is potentially infinite in length.

每个四面体都同其它四面体共享两个氧原子，形成一种可能为无限延伸的链。

I'm strongly against the death penalty — it's an eye for an eye.

我不赞成死刑——这是以牙还牙的报复行为。

And to get you the support you need, we're enlisting all elements of our national power: our diplomacy and development, our economic might and our moral suasion, so that you and the rest of our military do not bear the burden of our security alone.

并给你们所须的支援，我们正徵召国家所有各种的力量：我们的外交及发展，我们的经济力量与道德劝说，所以你们与其他军人不须要孤独地负起国家安全的责任。