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991.
船舶电站柴油机双脉冲H∞调速器的研究 总被引:4,自引:0,他引:4
船舶电力系统频率的稳定性主要取决于船舶电站柴油机调速系统的转速响应特性.为了抑制负荷的扰动,提高柴油机双脉冲调速器的动态精度,本文将H_∞控制理论应用于柴油机调速系统的设计,将系统的性能要求转化为标准H_∞控制问题.建立了采用双脉冲H_∞调速器的柴油机调速系统的数学模型,针对外部干扰和模型的不确定性,双脉冲H_∞调速器的设计可以归结为混合灵敏度问题.计算机仿真实验结果表明,本文设计的双脉冲H_∞调速器能在充分考虑系统模型不确定性的情况下,有效提高系统的动态精度和抑制扰动的能力,改善船舶电力系统频率的稳定性. 相似文献
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With the development of MEMS and the electronic devices's miniaturization and integration, a new kind of power sources that can satisfy the need for high energy density is required. Microbatteries are being researched abroad for their advantages of extreme thinness and long-term power supply. The development of MEMS microbatteries are reviewed and suggestedmagnetron sputtering in fabricating a high-performance microbattery. The technics as annealing are analyzed. The microbattery with a LiNi1-x Cox O2 cathode exhibited stable cycle ability and a high specific discharge capacity, which was attributed to the alloying effect of the LiNiO2and LiCoO2. 相似文献
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Bai H Sun R Ju J Yao X Zheng Y Jiang L 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(24):3429-3433
Spider-silk inspired functional fibers with periodic spindle-knots and the ability to collect water in a directional manner are fabricated on a large scale using a fluid coating method. The fabrication process is investigated in detail, considering factors like the fiber-drawing velocity, solution viscosity, and surface tension. These bioinspired fibers are inexpensive and durable, which makes it possible to collect water from fog in a similar manner to a spider's web. 相似文献
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Jian-zhong Wang Xuan-hui Qu Hai-qing Yin Ming-jun Yi Xian-jie Yuan 《Frontiers of Materials Science in China》2008,2(4):392-396
Iron powders with two different particle size distributions were compacted by high velocity compaction. The influences of
particle size distribution and impact velocity on green properties, including green density, springback, tensile strength
and bending strength etc., were studied with scanning electron microscopy (SEM) and a computer controlled universal testing
machine. The results show that the particle size distribution and the impact velocity strongly affect its properties. Wider
size distribution results in green compact with higher density and better strength. Furthermore, springback of compacts is
lower produced by the powder with wider size distribution, especially for radial springback. As impact velocity increases,
its green density and green strength gradually increases, but the increasing rate of density decreases gradually. No special
relation is found between springback and impact velocity. In addition, the axial springback and the bending strength are higher
than the radial springback and the tensile strength, respectively. 相似文献
999.
A.M.R Al-Marafie 《International Journal of Refrigeration》1987,10(6):364-366
A large proportion of annual peak electrical demand on utilities of the Gulf countries goes to satisfy the air conditioning load. This high peak demand, reaching nearly 70%, can be offset by the use of well designed stratified chilled water storage having high extraction efficiencies to shift peak power demand of the chiller to non-peak periods of the day. This Paper gives the salient features and performance results of a 7.5 m3 stratified chilled water reservoir for an experimental facility for a cool storage assisted air conditioning system. The experimental results on the reservoir, which has the same set of inlet/outlet connections for simultaneously serving the air handler and the chiller circuits, show a very high extraction efficiency of nearly 90% while maintaining stratified zones of 6 and 12°C. 相似文献
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