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71.
This study investigates the robust output tracking problem for a class of uncertain linear systems. The uncertainties are assumed to be time invariant and to satisfy the matching conditions. According to the selected nominal parameters, an optimal solution with a prescribed degree of stability is determined. Then, an auxiliary input via the use of an adapting factor, connected to the nominal optimal control, is introduced to guarantee the robustness and prescribed degree of stability for the output tracking control of the uncertain linear systems. This method is very simple and effective and can reject bounded uncertainties imposed on the states. A maglev vehicle model example is given to show its effectiveness. 相似文献
72.
ChujiangCai ZhigangShen MingzhuWang ShulinMa YushanXing 《中国颗粒学报》2003,1(4):156-161
This paper reports the use of a colloidal Pd^0 catalysis system to metallize the surface of precipitators separated from coal fly-ash, and metals such as Cu, Ni etc. are deposited on the precipitators surface. Alternatively, according to the characteristic surface of cenospheres, an Ag coating catalysis system is adopted to first deposit Ag on the cenospheres surface, followed, if necessary, by the deposition of other metals such as Cu, Ni, etc. on the Ag coating to produce monolayer and multilayer metal-coated cenospheres. The surface characteristics and the morphologies of the metal coatings are examined in detail with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) techniques. It can be shown that the quality of metal coatings derived from the Aa coatina catalysis system, is better than that of the colloidal Pd^0 catalysis system. 相似文献
73.
In this paper we obtain some sufficient conditions for the existence of non-constant periodic solutions of the following planar system with six delaysOur approach is based on the continuation theorem of the coincidence degree. 相似文献
74.
锥形阀压电薄膜泵的初步研究 总被引:3,自引:2,他引:1
提出一种适应高频工作状态的压电薄膜泵结构,实步分析了所采用的锥形阀的工作原理与作用,设计了试验泵结构,加工了样机,通过试验证明了锥形阀的有效性,为进一步的研究打下了基础。 相似文献
75.
In this paper, it is shown that the reflection error of Mur's first-order absorbing boundary condition (ABC) can be canceled effectively by applying the ABC twice to an electromagnetic (EM) field on two diagonally neighboring nodes on the x-t, y-t and t-t planes. Following this idea, we have developed a twofold Mur's first-order ABC (TMFABC), which is efficient to absorb both propagative and evanescent EM waves and very convenient for implementation to multilayered structures. TMFABC improves Mur's first-order ABC more effectively at lower frequencies. This is very important because most energy of a high-speed pulse is concentrated at lower frequencies 相似文献
76.
Properties of matrix-assisted laser desorption. Measurements with a time-to-digital converter. 总被引:2,自引:0,他引:2
Some properties of matrix-assisted laser desorption have been studied using single-ion-counting methods and a time-to-digital converter. The methods allow examination of the process for irradiances near the reported threshold for observation with a transient recorder. All measurements were made using bovine insulin as a test compound. We present direct evidence that an irradiance threshold near 10(6) W cm-2 exists for ion production, and that the process is a collective effect, either involving a large number of molecular ions (approximately 10(4) in a successful event or none at all. Above the threshold, the yield is found to scale with a high power (4th to 6th) of the irradiance. Measurements of initial velocity distributions indicate an axial velocity spread corresponding to approximately 50 eV and a radial velocity spread corresponding to approximately 2.4 eV. Thus the ejection or extraction mechanism appears to be strongly asymmetric. 相似文献
77.
Xianglei Mao 《Applied Surface Science》2007,253(15):6316-6321
The structure and evolution of the laser-induced vapor plume and shockwave were measured from femtosecond time resolved shadowgraph images. By changing the wavelength of the probe beam (400 and 800 nm), differences in the opacity of the vapor plume were measured as a function of delay time from the ablation laser pulse. The evolution of the temperature and electron number density during and after the ablation laser pulse were determined and compared for ablation in argon and helium background gases. A laser supported detonation wave (LSD) observed for ablation in argon, blocks the incoming laser energy and generates a high-pressure region above the vapor plume. 相似文献
78.
闪光灯泵浦的Nd:KGd(WO4)2激光器 总被引:1,自引:0,他引:1
报道了用闪光灯泵浦的掺钕的钨酸钆镓(Nd3+:KGd(WO4)2激光器.在重复频率1Hz,脉宽120μs的灯泵下,测量了不同透过率下激光输出能量,获得最大输出能量384mJ,斜率效率1.0%,外推阈值0.54J.在调Q运行时,Nd:KGW晶体的斜率效率为0.16%,最大输出能量46mJ. 相似文献
79.
用傅里叶变换红外扫描光致发光方法研究了Hg1-xCdxTe体单晶样品,该方法可直接得到HgCdTe晶片组分的二维平面分布,并可得到辐射复合在复合机制中所占比重的平面分布,以及晶体中非平衡载流子寿命的分布 相似文献
80.