排序方式: 共有35条查询结果,搜索用时 15 毫秒
1.
物流在玉溪经济发展中的重要性 总被引:1,自引:0,他引:1
胡飞 《玉溪师范学院学报》2001,17(Z1):49-51
玉溪经济的产业结构调整,必须寻求新的经济支柱,把玉溪建成滇中物资聚散地的设想是可以尝试的,那么必然就要发展物流业.物流在玉溪经济发展中具有重大作用,我们必须充分认识到物流在玉溪经济发展中的重要性,积极发展物流业. 相似文献
2.
Parkinson’s disease (PD) is a heterogenous disease caused by multifactorial etiology. PD is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra and the accumulation of Lewy bodies. In this study, two Drosophila PD models by exposing Drosophila to rotenone (sporadic PD models) are proposed, and the human α-synuclein A30P protein (family PD models) in Drosophila is expressed respectively. Both models recapitulated the main human PD symptoms including the loss of dopaminergic neurons... 相似文献
3.
孙桂秋 《湖南城市学院学报》2002,(6)
首先给出了函数的本式值和标式值的概念 .在限制使用极限的前提下 ,独立地推出了微积分理论 .并给出了在相对论方面的简单应用 ,求出了光子的静止质量 . 相似文献
4.
5.
6.
7.
8.
为提高动态电压恢复器(Dynamic Voltage Restorer,DVR)补偿电压的输出精度,在计算分析DVR数学模型的基础上,对DVR开环控制和PD闭环控制进行仿真,并利用MATLAB软件仿真验证了两种控制方式下不同补偿策略的补偿效果。结果表明,PD闭环控制可有效补偿电压凹陷,改善系统的动态补偿特性。 相似文献
9.
Timothy S. Farajian 《Journal of The Franklin Institute》2007,344(5):426-438
Vibration suppression of a structurally damped beam via open and closed-loop controls is investigated. In doing so, minimization of a weighted, energy-based performance measure leads to closed-form expressions for optimal open-loop parameters in terms of feedback gains. The control problem is then completed by optimizing these feedback parameters numerically. Methods to determine optimal terminal time of control are also presented. Furthermore, techniques are established to optimize the response and performance of a system experiencing a known feedback time delay. Different types of optimization are proposed and, for each one, the trade-off between performance and computational efficiency is fully discussed. 相似文献
10.
常规的灭菌器工作时需外配一台蒸汽发生器,导致灭菌系统结构复杂价位高。文章介绍一种装配于灭菌器内部的小型蒸汽发生器,该蒸汽发生器采用分段PID控制,文章还介绍了该蒸汽发生器的软硬件设计。 相似文献