二十面体的

V-shape grooves exist in twinned crystal planes of fivefold twin. As for thermodynamics and kinetics, the grooves are helpful for diamond grains of fivefold twin to grow.

正二十面体和正十面体颗粒都是"五重孪晶"结构，在颗粒表面上与五重孪晶面对应的区域形成V-形槽，这种V-形槽对五重孪晶金刚石颗粒的长大有热力学和动力学的有利作用。

On the basis of the frame of dodecahedron, we apply the method of "spherical stretching" to the frame, we can obtain a novel polyhedron with I_h symmetry, which contains 72 pentagons.

我们在十二面体框架的基础上，利用"球面拉伸"的方法，得到新的具有二十面体对称性，72个五边形构造的的多面体结构。

This method has been used to calculate electronic structures of the icosahedral,tetrahedral and dihedral fullerenes and some stability rules are obtained.

这种方法已经用于系统地研究具有二十面体群、四面体群和二面体群对称性的各富勒烯同系列，并且得到规律性的结果。

The structures and stabilities of the ground-states for Cu13-nAgn clusters have been studied by Gupta model potential based on tight binding second moment approximation in combination with a genetic algorithm. It is found that the lowest energy structures of the pure clusters (n=0,13) are perfect icosahedron, and the structures for the bimetallic clusters (n=1～10) have stable structure which are slightly deformed with respect to the perfect icosahedron, The Cu atom prefers to occupy the center of the clusters with higher coordination numbers.

在混合团簇基态结构优化的遗传算法方案中增加了交换算子，结合Gupta紧束缚模型势研究了Cu13-nAgn团簇的最低能量结构，选择合适的交换和杂交概率，可有效地提高优化效率，优化结果表明，Cu13和Ag13是全对称的二十面体，n=1～10的混合团簇能形成稳定结构，其构型是在二十面体基础上发生畸变，Cu原子趋于处在团簇中心，随着Ag原子数目的增加，原子间的平均距离单调增加，团簇的结合能单调减小，Cu2Ag12和CuAg12只存在亚稳结构。

High yield,well-defined gold nanocrystals with shape of icosahedron were synthesized by the rapid reduction of gold precursors with ethylene glycolin presence of polyunder hydrothermal condition for 1 h.Au icosahedron is one of multiple twinned particleswhich has 20 faces,each were enclosed by {111} facet.

采用水热法在乙二醇体系中成功的制备出了形状规则、尺寸为200-300nm的二十面体金纳米粒子，研究结果表明，所合成的纳米颗粒是面心立方晶型，每个晶面都是{111}面。

At each penton, a hole (φ=20〓) can be seen connecting the inside and the outside of the capsid, and there is a hole (φ=12〓) at each hexton and the center of 2-fold axis, so there are 132 holes in total at the surface of CSBV.

应用冷冻电镜技术和计算机三维结构重构的方法，我们测定了CSBV核衣壳的三维结构，分辩率为25 〓，病毒的核衣壳是按T=1（P=3）的对称结构排列二十面体，病毒表面比较光滑，有12个五邻体、60个六邻体的结构，每个五邻体的中央有孔洞，六邻体的中央也有孔洞，另外在2次轴的位置上也有孔洞，这样病毒共有132个孔洞，五邻体的孔洞的直径为20 〓，而六邻体和二次轴的孔洞的直径月为12 〓。

In contrast to ordinary liquid and amorphous alloys, the number of 1551 bonds related to the icosahedral structure becomes very smaller with the decrease of temperature,but the numbers of 1311,1301,1201 bonds related to the rhombohedral structure are increased remarkably.

结果表明，与通常液态及非晶态金属相反，随着温度降低，与二十面体相关的1551键型数越来越少，而与菱面体相关的1311，1301和1201键型数目显著增加，最后形成以菱面体结构单元为主的非晶态结构。

This fact disproves an assumption that λ-phase is an approximant of the IQC.

但是我们研究发现λ相与在其基础上生成的二十面体相之间没有固定的取向关系，这反驳了λ相是二十面体相的近似相的假设。

There are three forms of symmetry in virus capsids: icosahedral , helical and complex forms.

壳粒排列的方式使病毒的结构呈几何对称，病毒衣壳有三种对称形式：二十面体立体对称、螺旋对称、复合对称，螺旋结构呈杆状，而二十面体由对称的亚单位组成近似的球状，非对称的衣壳是较复杂的形式，往往与细菌病毒有关。

On the basis of the frame of dodecahedron, we apply the method of "spherical stretching" to the frame, we can obtain a novel polyhedron with I_h symmetry, which contains 72 pentagons.

我们在十二面体框架的基础上，利用&球面拉伸&的方法，得到新的具有二十面体对称性，72个五边形构造的的多面体结构。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐