十二面体的

The variable geometry truss mechanisms have been studied extensively and systematically by this project. The research plan has been completed all sidedly, and expected results have been obtained. Three new kinds of combination decahedrons and a new class of variable geometry truss mechanism, which is composed of an octahedron and three tetrahedrons connected in parallel form, are proposed. The position analyses for decahedrons, dodecahedrons, triple-octahedrons, combinations decahedron and a new type of structure of variable geometry truss mechanisms are presented by introducing additional extra linear displacement sensors and using resultant elimination and homotopy continuation algorithms. The method of kinematical analysis of variable geometry truss mechanisms is established.

课题组对变几何桁架机构进行了深入的研究，全面地完成了研究计划，取得了预期的成果；提出了三种新的十面体组合机构以及由一个八面体和三个四面体组成的新型变几何桁架机构的结构形式；应用结式消元、附加传感器和同伦方法等提出了十面体、十二面体、三重八面体、组合十面体和新型变几何桁架机构的位置分析方法；建立了变几何桁架机构运动分析的一般方法；建立了简洁的凯恩和拉格伦日动力学的模型；应用有限元和子结构方法，提出了变几何柞架机构弹性动力学模型，导出了逆动力学方程的显式形式；设计和研制了一台可折叠的八面体变几何杵架机构装置等。

Our results show that the duality of self-dual tetrahedral link is "trivial", and the duality of hexahedral and octahedral link as well as dodecahedral and icosahedral link are "nontrivial".

从构型角度考虑，四面体链环的自对偶是"平凡"的，六面体链环和八面体链环，十二面体和二十面体链环的对偶是"非平凡"的。

Gastaldi and co-workers have observed two types of contrasts in Al-Pd-Mn IQCs: black-white double-lobe and loop-shaped, by using X-ray topography, and the facetted dodecahedral pores by phase-sensitive radiography.

Gastaldi领导的小组在结合利用X射线形貌术以及相位敏感成像术研究Al-Pd-Mn二十面体准晶单晶中的缺陷时发现两种衬度，其中已知黑白双瓣衬度是由于准晶中的五角十二面体空洞引起，而对于环形衬度则除了知道退火行为不同于位错从而不太可能是位错圈外，基本上对其缺陷的几何及性质不甚了解。

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。

The Dodecahedron takes the travelers to see the Mathemagician, after giving them a tour through the Numbers Mine, where digits are pulled from the earth like jewels.

需要的十二面体的旅客看到Mathemagician后，让他们通过参观数字矿山，其中数字撤出地球像珠宝。

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。

However, when occurring in Mesozoic remelted granite, pyrite is featured mainly by high gold content in pentagonal dodecahedron and in its complex; low content in cubic pyrite; Au/Ag ratio between 1-2; both N and P types of pyrite present in most deposits and P type only in a few deposits.

产于中生代重熔花岗岩中时，黄铁矿以五角十二面体居多，五角十二面体及其聚形含金较高，立方体含金性较差；Au/Ag比值在1-2之间，As的含量较高(＞600×10〓)；Co、Ni的含量则较低，一般为10n×10〓；热电性以既有P型又有N型的P、N混合型为特征，少数金矿床表现为单一的P型。

Located in the prospecting lines Nos.47 and 37-33 on the middle 270m section, the mineral typomorphic characteristics are as follows: pyrite possesses the combination of octahedron with pyritohedron, pyritohedron with octahedron, etc It appearsas hole-centre and mix center conduction, if being electron-centre conduction, the absolute magnitudes of thermoelectromotive force and thermoelectromotive coefficient of pyrite are bigger relatively; pyrite contains Cu; the relative absorbency in quartz D(subscript H2O0.9403, D(subscript CO2)0.1961, D(subscript CO2)/D(subscript H2O)0.2591 in prospecting lines 37-33 is smaller than average D(subscript H2O1.3267, D(subscript CO2)0.3090, D(subscript CO2)/D(subscript H2O)0.338 2 in the deposit.

江西茅排金矿区270m中段47勘探线及37~33勘探线的矿物标型特征为：黄铁矿形态见有八面体和五角十二面体，五角十二面体和八面体等聚形；出现空穴心型导电和混合型导电黄铁矿，若为电子心型导电黄铁矿，其热电动势和热电系数的绝对值相对较大；黄铁矿成分中检测出Cu；石英相对吸光度（37~33勘探线）D(下标 H2O)0.9403，D(下标 CO2)0.1961，D(下标 CO2)/D(下标 H2O)0.2591，略低于矿区研究样品的平均值D(下标 H2O1.3267，D(下标 CO2)0.3090，D(下标 CO2)/D(下标 H2O)0.3382。

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。

Our results show that the duality of self-dual tetrahedral link is "trivial", and the duality of hexahedral and octahedral link as well as dodecahedral and icosahedral link are "nontrivial".

从构型角度考虑，四面体链环的自对偶是&平凡&的，六面体链环和八面体链环，十二面体和二十面体链环的对偶是&非平凡&的。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。