排序方式: 共有86条查询结果,搜索用时 218 毫秒
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闵琪 《郑州航空工业管理学院学报(管理科学版)》2007,25(1):60-63
以资本结构的税收效应为研究主线,以MM模型作为研究工具,对其假设条件不断扩展,在结合中国实际税收制度的基础上,分析税收对企业资本结构的影响,并在中国目前税收制度条件下,进一步测算MM模型的税收效应。 相似文献
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闵远光 《郑州航空工业管理学院学报(管理科学版)》2003,21(2):9-11
分析了信息缺陷和人的信息处理能力的不足与市场机制之间的矛盾关系,提出信用产生的原因,以及依靠监管手段来规范市场。 相似文献
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针对传统多智能体轨迹估计算法信息交换量大,计算量随群规模指数增长,可扩展性差等诸多不足,提出了一种基于超松弛迭代(SOR)的分布式多智能体轨迹估计算法,通过将最大似然(ML)准则下的轨迹估计转化为两级线性优化问题,并综合利用分布式超松弛迭代(Distributed SOR)和标记初始化方法,加快求解速度并简化信息交换流程,最终实现了多智能体位姿轨迹优化和协作定位。实验表明,所提的分布式方法能达到集中式算法的精度水平,在49个智能体规模条件下,位置估计误差小于0.15 m,姿态估计误差小于0.03°,且数据交换量仅到现有主流分布式方法DDF-SAM的0.06%,能很好用于大规模集群的场景。 相似文献
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Lightweight structure of a phase-change thermal controller based on lattice cells manufactured by SLM 总被引:1,自引:0,他引:1
Hao ZHOU Xiaoyu ZHANG Huizhong ZENG Huning YANGa Hongshuai LEI Xiao LI Yaobing WANG 《中国航空学报》2019,32(7):1727-1732
Thermal controllers equipped with phase-change materials are widely used for maintaining the moderate temperatures of various electric devices used in spacecraft. Yet, the structures of amounts of thermal controllers add up to such a large value that restricts the employment of scientific devices due to the limit of rocket capacity. A lightweight structure of phase-change thermal controllers has been one of the main focuses of spacecraft design engineering. In this work, we design a lightweight phase-change thermal controller structure based on lattice cells. The structure is manufactured entirely with AlSi10 Mg by direct metal laser melting. The dimensions of the structure are 230 mm × 170 mm × 15 mm, and the mass is 190 g, which is 60% lighter than most traditional structures(500–600 g) with the same dimensions. The 3 D-printed structure can reduce the risk of leakage at soldering manufacture by a welding process. Whether the strength of the designed structure is sufficient is determined through mechanical analysis and experiments. Thermal test results show that the thermal capacity of the lattice-based thermal controller is increased by50% compared to that of traditional controllers with the same volume. 相似文献
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A study is conducted on a new airworthiness compliance verification method based on pilot-aircraft-environment complex system simulation. Verification scenarios are established by "block diagram" method based on airworthiness criteria. A pilotaircraft-environment complex model is set up and a virtual flight testing method based on connection of MATLAB/Simulink and Flightgear is proposed. Special researches are conducted on the modeling of pilot manipulation stochastic parameters and manipulation in critical situation. Unfavorable flight factors of certain scenario are analyzed, and reliability modeling of important system is researched. A distribution function of small probability event and the theory on risk probability measurement are studied. Nonlinear function is used to depict the relationship between the cumulative probability and the extremum of the critical parameter. A synthetic evaluation model is set up, modified genetic algorithm (MGA) is applied to ascertaining the distribution parameter in the model, and a more reasonable result is obtained. A clause about vehicle control functions (VCFs) verification in MIL-HDBK-516B is selected as an example to validate the practicability of the method. 相似文献
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一种腿臂融合四足机器人设计与分析 总被引:1,自引:0,他引:1
设计了一种腿臂融合的四足机器人,其具有腿臂功能复用的分支,不仅可以实现行走,还可以进行操作。对该机器人的行走模式和操作模式进行了研究,首先,建立了机器人单腿运动学模型,推导出机身整体的逆运动学;其次,对腿臂功能复用分支的5自由度操作臂模型进行了运动学分析,提出了欠自由度操作臂保证末端位置和末端姿态2种情况下的逆运动学最优求解方法,并分别给出了位置或姿态偏差;然后,建立了支撑面、支撑腿、本体、操作臂所组成的串并混联机构的运动学模型,利用本体位移补偿操作臂末端位置偏差,从而实现操作臂末端精确操作;最后,对机器人本体、操作臂以及串并混联机构的工作空间进行了仿真,并利用实验验证了该机器人腿行走和臂操作的功能。 相似文献
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对采用热等静压工艺制备的粉末Ti-6Al-4V合金的固溶时效热处理工艺进行了研究,探讨了不同的固溶温度、时效温度及时效时间对该合金材料力学性能的影响。结果表明,当固溶时效工艺为935℃ 36min 水淬、470℃ 6h 空冷时,该合金材料的综合力学性能较佳,这说明固溶时效热处理参数的合理选择对于进一步地提高Ti-6Al-4V粉末冶金件的力学性能起着重要作用。 相似文献