二十四面体

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。

The resulting materials were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, Nuclear magnetic resonance and Photoluminescence. Those spectra reveal that by adding SiO2 to YAG:Ce precursor, the lattice constant decreases while vacancies are generate due to the co-dopant ions (Si4+) replaces in the place of Al3+ sites of YAG:Ce system. YAG:Ce phosphors with Y3+ dodecahedral site replaced by Ce3+ and diffused effectively as an activator, as a result the photoluminescence intensity increased about ~20-30%.

研究成果显示，掺杂SiO2之YAG：Ce萤光粉经过高温热处理后，由X光绕射、红外线吸收光谱仪以及核磁共振可以得知，当SiO2添加量增加时，YAG：Ce晶格常数会因为Si4+取代Al3+的四面体晶格位置而变小，同时产生将YAG：Ce之铝离子空位缺陷，使活化中心更有效地在YAG：Ce主体中扩散取代Y3+的十二面体晶格位置，提高其发光性质约20~35%。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了