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91.
吴慧 《上海交通大学学报(哲学社会科学版)》2007,15(1):58-65
唐僧一行参与乃至领导了盛唐时期的皇家天文台的工作,编制了著名的《大衍历》,本文从文化角度对沙门一行制历的因缘加以考证,认为促成一行制历的原因:一是政治统治的需要,二是沙门一行的俗家家世背景,三是沙门一行的宗教身份,且三者层层递进。其中一行的宗教身份,解释了其复杂知识结构以及《大衍历》域外天文学知识的可能来源,同时一行囊天台宗和律宗的修行身份并入于密教,加上文献材料中所体现出来的道教背景,契合了玄宗朝的宗教政策,是获得玄宗信赖的重要原因。而对于沙门一行制历的缘由,对于一行宗教背景中的道教成份,也是前贤的研究所忽略的。 相似文献
92.
An improved Monte Carlo method was used to simulate the motion of electrons in c-C_4F_8 and SF_6 gas mixtures for pulsed townsend discharge. The electron swarm parameters such as effective ionization coefficient, [AKα-] and drift velocity over the E/N range from 280~700 Td(1Td=10-21 V·m2) were calculated by employing a set of cross sections available in literature. From the variation cure of [AKα-] with SF_6 partial pressure p, the limiting field (E/N)_lim of gas mixture at different gas content was determined. It is found that the limiting field of c-C_4F_8 and SF_6 gas mixture is higher than that of pure SF_6 at any SF_6 mixture ratio. Simulation results show excellent agreement with experiment data available in previous literature. 相似文献
93.
This paper presented a new-type CNC curve grinding machine, in order to conquer the disadvantages of conventional NC curve grinding machine and improve surface quality, dimensional accuracy and machining efficiency. The new-type grinder adopts some high and new technologies: ① the normal tracing device could make grinding wheel coincide with the normal direction of the machining points in work piece, and improve surface quality and dimensional accuracy; ② the digital image on-line recognition system could monitor machining process and compensate wheel wear in real time; ③ linear motor drive mechanism could realize the exact adjustment of the grinding head digitally and increase the machining efficiency. The math models of normal tracing and circular tolerance zone were presented. The experimental results show that the new-type CNC curve grinding machine equipped with the three devices mentioned above is easy to realize the precision grinding of any complex curve, and improve surface quality, dimensional accuracy and machining efficiency. 相似文献
94.
The eigenvector of a module with six adjacent module's state was constructed according to self-reconfigurable robot M-Cubes and the configuration of system was expressed with the eigenvectors of all modules.According to the configuration and motion characteristics of the modules,a 3-dimension motion rule set was provided.The rule sets of each module was run according to eigenvector of the module after the motion direction of system decided and motion rules were selected.At last,the rapid and effective motion and metamorphosis were realized in system.The rule sets are operated on three systems and the distributed motion of system is fully realized.The result of simulation shows that the 3-dimension motion rule sets has perfect applicability and extensibility.The motion steps and communication load of the modules increase with the module number in linear. 相似文献
95.
浅谈建筑施工企业工程造价控制的若干方法 总被引:2,自引:0,他引:2
对建筑施工企业而言,建设工程项目的成本直接关系到项目的成败,关系到建筑施工企业的发展,同时也是工程竞标的主要因素。阐述了建筑施工企业工程造价控制的一些做法,诸如:合理预测工程项目的成本,抓好工程实施阶段的成本控制和做好工程实施阶段实质性管理工作。由此实现施工管理效益最大化。 相似文献
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城市轨道车辆牵引仿真计算 总被引:7,自引:1,他引:7
分析了城市轨道车辆牵引计算的动态数学模型,通过预算列车特性为其逆变器和电动机的选型提供参考;简要介绍了用面向对象的C++语言实现的仿真计算程序。实践表明该软件具有一定的实用价值。 相似文献