正二十面体

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。

The several shapes of diamond grains have been observed in SEM: truncated cube, octahedron, truncated cubo-octahedron, twinned cubo-octahedron, twinned regular decahedron and twinned regular icosahedron. Most of diamond grains are octahedron.

用扫描电子显微镜观察到多种外形的金刚石颗粒：截顶立方体、未截顶正八面体、截顶立方八面体、孪晶立方八面体、正十面体和正二十面体的金刚石颗粒。

Goldberg got a class of polyhedra which are icosahedral symmetry by appending hexagons on regular dodecahedron by rule in 1937. They are called Goldberg polyhedra which provides a new approach for polyhedral molecule design.

1937年，数学家Goldberg通过在正十二面体上有规律地添加六边形面得到一类具有二十面体对称性的多面体，即Goldberg多面体。

Regular icosahedron ; regular dodecahedron ; quasicrystal ; conjugate fractal structural model ; conjugate fractal structural model of quasicrystal ; Penrose pattern ; high resolution structural image by electron microscopy.

正十二面体；正二十面体；准晶体；共轭分数维模型；准晶共轭结构模型； Penrose拼图；高分辨电子显微结构图

By constructing a sphere hexagonal grid system based on the Truncated Icosahedrons Projection, this paper focuses on the study of the address coding mechanism of the sphere hexagonal grids, including the hierarchy coding schemes, the study of the positional relations among the grid units and the mutual conversion between the address codes of the grid units and the geographical coordinates.

本文通过构建基于截顶正二十面体投影的球面六边形网格系统，对球面六边形网格的地址编码机制进行了重点研究，包括网格的层次编码方案、网格单元位置关系研究和网格单元地址码与地理坐标之间的相互转换。

The measurement is simulated by ""regular icosahedron "" method, utilizing the direct current moment electric motor and the photoelectrical axis angle encoder, the rotation of the shot carrier and the CCD camera is completed, and can orientation the rotating angle, so that the system can make the CCD camera to measure the square diagraph in 16 independent projections.

该系统的研制是利用"正二十面体"方法进行模拟，直流力矩电动机和光电轴角编码器配合使用，完成载物台和CCD相机的旋转运动和角度定位，使CCD相机能够实现对十六个独立方向上的投影测量。

We obtain three classes of polyhedra which have high symmetry. they are regular tetrahedral class belonging to tetrahedral group , regular hexahedral class and regular octahedral class belonging to octahedral group.

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。

Marine birnavirus, a member of the genus Aquabirnavirus, family Birnaviridae, is an unenveloped icosahedral virus with two genomes of double-stranded RNA.

海生双RNA病毒是类无囊膜、正二十面体、带有两节段双链RNA基因组的病毒，属于双RNA病毒科水生双RNA病毒属成员。

Morphologically and biologically, the triple-layered rotavirus particles are composed of three protein capsids, outer capsid includes VP4 and VP7, the middle is VP6, and the core is composed of VP2. VP1, VP3 and the 11 segments of double-stranded genomic RNA.

完整的轮状病毒颗粒直径约70nm，为正二十面体结构，由三层蛋白壳包绕，外壳为VP4及VP7蛋白，VP6蛋白构成病毒第二层蛋白壳，最内层为核壳，由结构蛋白VP1、VP2、VP3组成，核壳内包含有11个分节段的病毒双链RNA基因片段。

The continuing of the process produces icosahedra of even higher orders (a2, a3,…,an).

实质上，这一模型可以看成正二十面体与正十二面体共轭生成的结果。

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