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141.
Design and performance evaluation of an ultrasonic motor was discussed in [Wen et al., Thin-disc piezoelectric ultrasonic motor. Part I: design and performance evaluation, Ultrasonics]. Higher precision position control of piezoceramic ultrasonic motor depends on mechanical design and servo control of a very precise and adequate metrology. This paper proposes the design of a driving circuit and controller to deal with non-linearities behavior in the model of piezoceramic-driving ultrasonic motor. The performance of the driver and the effectiveness of the proposed controller are demonstrated by command inputs of sinusoidal and step signals. For comparison purpose, the ultrasonic motor is controlled using two methods: i.e., proportional-integral-derivative (PID) and sliding-mode control (SMC). It was proven that SMC would compensate automatically for unmodeled behaviors such as piezoceramic non-linearities and mechanical stick-slip phenomena. Furthermore, SMC scheme has been successfully applied to position tracking to demonstrate the excellent robust performance in noise rejection. 相似文献
142.
Yong Ouyang 《Proceedings of the American Mathematical Society》2003,131(12):3703-3709
We consider the deformation of the complex structure of . We show that a harmonic deformation on equipped with the Fubini-Study metric is trivial if its supernorm is appropriately small.
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设计并合成了一系列以三苯胺为核,芴衍生物为外围基团的有机蓝光小分子,该合成通过Suzuki反应在9-芳基芴的2位和(或)7位引入相同或不同取代基作为模块,并利用Friedel-Crafts反应将4-甲基三苯胺与这一系列模块结合.用NMR,MS和元素分析进行结构表征.荧光测试结果表明该类化合物溶液的荧光发射波长范围在442~466 nm之间,属蓝光发射.电化学测试显示该类材料的HOMO能级位于-5.15~-5.19 eV之间.差示扫描量热仪与热重分析得出化合物的玻璃化转变温度在166℃以上,热分解温度高于398℃,表明该类材料具有良好的热稳定性. 相似文献
147.
Ouyang Guangzhong 《数学年刊B辑(英文版)》1986,7(3):365-372
Let G be a locally compactb abelian group and $\[{A_p}(G)\]$ the p-Fourier algeba of Herz.
This pepar studies the space $\[{A_{1,p}}(G) = {L_1}(G) \cap {A_p}(G)\]$ with convolution product. It is
proved that $\[{A_{1,p}}(G)\]$ is a character Segal algebra. Moreover, for the multipliers of $\[{A_{1,p}}(G)\]$ the author proves that $\[M({A_{1,p}}(G),{L_1}(G)) = M(G)\]$ and $\[M({A_{1,p}}(G),{A_{1,p}}(G)) = M(G)\]$
provided G is noncompact. If G is discrete, then $\[M({A_{1,p}}(G),{L_1}(G)) = {A_{1,p}}(G)\$ and
$\[M({A_{1,p}}(G),{A_{1,p}}(G)) = {A_{1,p}}(G)\]$ 相似文献
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合成了三种新型含噻吩环大环Schiff碱及其中一种与镧,钍的配合物。它们的结构均经IR,HNMR和元素分析表征。 相似文献
150.
In this paper, we develop a deterministic inventory model for deteriorating items with two warehouses by minimizing the net present value of the total cost. Deterioration rates of items in the two warehouses may be different. In addition, we allow for shortages and complete backlogging. We then prove that the optimal replenishment policy not only exists but also is unique under some condition. Further, the result reveals that the reorder interval based on the average total cost, if it exists, must be longer than that derived using net present value. Finally, we use Yang’s [H.L. Yang, European Journal of Operational Research 157 (2004) 344–356] numerical example to illustrate the model and conclude the paper with suggestions for possible future research. 相似文献