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This paper presents new uncertain parameter variation bounds for linear discrete-time systems to preserve asymptotic stability. The Lyapunov method is utilized to treat both structured and unstructured uncertainties, and the results are optimized with respect to a parameter in the inequality used. When applied to examples considered by previous authors, our results give less conservative bounds. 相似文献
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结合镇海炼化Ⅱ套催化改造,将PX联合装置的低温位热进行合理利用,形成Ⅱ套催化气分装置和PX联合装置热联合。热联合后既节约Ⅱ套催化气分装置的低压蒸汽消耗,又降低了PX装置的空气冷器电耗,达到能量合理利用的目的。 相似文献
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The method employed in the measurement of plasma spreading velocity νs, in power thyristors and the results obtained are reported in detail. To induce νs to be primarily one-dimensional the thyristors wore rectangular in configuration with gate contacts to measure the arrival of the plasma, being placed at regular intervals around the rectangular (alloyed) cathode. Gold-doped devices were compared with geometrically similar thyristors nominally gold free. Values of νs for gold-doped thyristors were persistently, though not always, lower. The current gain of the constituent transistors has also been measured and attempts are made to correlate these to the measured νs values. The currant, gains, particularly of the n-p-n section, prevailing in the ‘ off ’ region of a thyristor during a switch-on transient are contrasted with those obtaining during current gain measurements and are thought to be responsible, in conjunction with the lowered life-time in the wide n-basr regoin of the p-n-p section, for the lowered νs values of gold-doped thyriators. 相似文献
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为实现古陶瓷化学组成的无损定量分析,研制一组陶瓷定量分析标准样品,样品中元素的含量稳定性和分布均匀性是两个重要技术指标。本文用能量色散X射线荧光光谱仪(EDXRF)对标准样品进行均匀性检验,主要分析了Al、Si、K、Ca、Ti、Mn和Fe这7种元素。利用SPSS软件对归一化处理的净峰面积计数作了相对标准偏差计算和F统计检验。结果表明:12个配方中除DY2和JDZ4需进一步分析外,其余10个配方在束斑Ф=1mm区域内元素分布均匀性较好,基本满足古陶瓷无损定量分析标准样品的均匀性要求。 相似文献
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MICHAEL V. SEFTON WAN FONG IP GORDON ROLLASON MARK W.C. HATTON WALTER ZINGG 《Chemical Engineering Communications》2013,200(3-5):141-154
Heparin immobilized onto polyvinyl alcohol (PVA) by action of glutaraldehyde has been shown to be biologically active in a novel parallel flow arteriovenous shunt in dogs. The hepann-PVA hydrogel originally devised by Merrill and his collaborators was applied as a coaling to chromic acid etched polyethylene lubing. A pair of Y-connectors was used to divert < 2% of the flow in the AV shunt through the heparinized tube, which remained patent for longer Ihan two hours while a control tube without heparin was occluded within 30 minutes at a main shunt flow rate of ~l50mL/min. This enhanced patency was achieved without significant release from the surface, consistent with earlier experiments attributing the thromboresistance of the heparin-PVA hydrogel to the formation of a surface bound inactive thrombin-antithrombin III complex. Radiolabelled thrombin adsorbed onto beads made from the gel was readily displaced by arvinized plasma, indicating that the inactive complex was not itself permanently bound to the surface.
These results demonstrate the utility of Merrill's hydrogel for preparing materials with potential long lerm thromboresistance and for testing the validity of the hypothesized limitations to the long term use of immobilized heparin. 相似文献
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用于D类放大器的ΔΣ调制器系统分析与设计 总被引:1,自引:1,他引:0
D类放大器具有效率高、功耗低的优点,已逐渐被应用到音频领域。为了克服传统D类放大器的内在缺陷,引入了ΔΣ调制技术以及闭环特性。但由于ΔΣ调制技术的系统设计对整个放大器非常重要,而且设计方法较复杂,因此需要借助于Matlab工具。分析了ΔΣ调制技术对D类放大器的非线性、噪声和EMI等性能的改善,对几种高阶ΔΣ调制器结构进行比较分析,最后制定详细的系统设计方法、步骤,并用Matlab工具进行系统建模与仿真。通过仿真结果,验证了设计系统的有效性,从而为实际电路设计提供基础。 相似文献
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Dependence of Effective Anisotropy on Grain Size in Nanocrystalline Nd2 Fe14 B Hard Magnetic Material 总被引:2,自引:2,他引:0
Anisotropy of material is the key factor determin ing coercivity and anisotropy of nano grain is dramati cally influenced by grain size[1~2]. So the coercivityof nano magnetic material with different grain sizeswould have obvious difference.… 相似文献