四面体的

Ti-Si composite materials are mixed at atomic scale, and Ti-O-Si bond appears in all of the samples with different TiO2 content; the mixed oxides are mainly existed in the form of amorphous pattern, anatase appears when the TiO2 content is more than 80%, but compared with the intension of pure TiO2, it has not integrate structure. The acetic content has great influence in the specific area and crystal structure of the mixed oxides. 20TiSi has good heat stability, still possesses 11m2/g after calcined at 1100℃; calcinations on the large scale of temperature does not cause the break of Ti-O-Si bond, TiO2 is well dispersed in 20TiSi calcined at 1100℃, and it still existed in the form of amorphous.

结果表明：制得的Ti-Si复合氧化物具有很高的比表面积，在TiO_2含量为10％时达到681.5m~2／g，Ti原子进入Si-O四面体结构中，形成Si-O-Ti键，复合氧化物的稳定性好，当TiO_2含量低于60 wt％时，以无定型形式存在；当含量为80％时，出现锐钛矿型TiO_2，但与纯TiO_2相比晶型不完整：醋酸对Ti-Si复合氧化物的比表面积、晶型都有很大的影响；TiO_2含量为20％的20TiSi经1100℃高温焙烧后，仍有较高的比表面积(11m~2／g)，稳定性好，在较宽的温度范围内焙烧，没有引起Ti-O-Si键的断裂，分散度高，没有出现晶型TiO_2。

In view of that conventional algorithms of collision detection spend a lot of detection time on complex polyhedrons, an algorithm to divide a convex polyhedron was presented and proved.

针对传统的碰撞检测算法对于复杂多面体之间的碰撞检测时间过长的缺陷，提出并证明了一种凸多面体的剖分算法，该算法能将复杂的凸多面体剖分为简单四面体，利用基于MPI(Mes-sagePassingInterface)并行处理的方法来提高碰撞检测的实时性。

Hybrid meshes, consisting of mixed element types, allow you to combine the ease of tetrahedral meshing on complex geometries with the advantages of traditional hexahedral cells in regions of less geometric complexity.

混合网格组成的混合元素类型，让您的难易程度相结合的四面体网格的复杂外形的优势与传统的六面体细胞较少地区的几何复杂性。

In the 2A1 distorted trigonal bipyramid structure ,the single non equivalent Ga atom has the population of 4s 4p ,while the two equivalent Ga atoms have the population of 4s 4p .this compares with a Ga population of 4s 4p in the undistorted D3h structure ,hence the jahn-teller distortion causes depletion of the charge density on the 4s orbital of the non-equivalent Ga atom, and enhancement of charge density on the 4s orbital for the two equivalent atoms .an opposite trend is observed for the 4p orbitals of these Ga atoms .the P population for the two equivalent atoms is 3s 3p .the populations of the other 2B1 state with the edge-capped tetrahedral structure are similar with the exception that all three Ga atoms have similar but not identical populations .

在2A1被变形的三角bipyramid结构，唯一非等效Ga原子有4s 4p的人口，而二个等效Ga原子在未变形的D3h结构有4s 4p 。this的人口和4s相比4p的Ga人口，因此jahn出纳畸变在non-equivalent Ga原子的4s轨道导致电荷密度的取尽，并且电荷密度的改进在4s轨道为二个等效原子。an在趋向对面对这些Ga原子4p轨道被观察。the人口为二个等效原子是另一个2B1状态3s 3p 。the人口与边缘加盖的四面体结构是相似的P 除之外全部三个Ga原子有相似，但不相同人口。

The meshwork results are obtained from the later pictures. They clearly show the structure of four-dimension reseau and some meshwork results of shell data. The reason why the whole results are not achieved is that there are too many circumstances in which five or more dots share the same orb. In this case, the principle Delaunay is not in point any more, then the process of establishing meshwork will be intermitted.

后面的四幅图是后来所作的工作，得到了一个正方体四顶点以及其中心点的建网结果，从这里能清楚地看到四面体网格的结构，还有对贝壳数据点云的部分建网结果，之所以没有完成整个贝壳数据的建网是因为数据中存在较多的五点或五点以上共球的情况，这种情况下Delaunay准则不再适用，建网会中断，所以只完成了一个部分。

Although CdS and NiSe belonged to the same crystal system, they had a great difference in the morphology of products produced in ethylenediamine by a solvothermal process. By making a crytallographic comparison between CdS and NiSe, I thought that fourcoordinated crystals were more prone to grow one-dimensionally in the stacking direction of tetrahedrons. This hypothesis could also be embodied in many examples.

硫化镉和硒化镍的晶体结构都为六方晶系，但在以乙二胺为溶剂的溶剂热条件下合成出的产物形貌有很大的差别，我们通过对两类晶体结构的结晶学比较，我们认为4配位的晶体更趋向于生成一维纳米材料，并提出生长方向即为四面体堆积方向，这一假设也能得到许多例子的证实。

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。

Furthermore, the effects of ligands, metal and reaction time on the reaction were also researched, and the process of new ligand-metal catalysis for Diels-Alder reaction was also analyzed according to Evans" square planar mode and Corey"s tetrahedral manner.

我们对影响配体对映选择性能的各种因素，如配体结构、金属离子、反应时间等进行了研究，而且根据Evans的平面四方形模式与Corey的四面体过渡态理论为新配体—金属配合物催化的该反应提出了可能的反应机理，并对产物的优势构型作了理论分析。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。