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101.
102.
In this paper, the problem of non‐fragile observer‐based H ∞ control for discrete‐time switched delay systems is investigated. Both data missing and time delays are taken into account in the links from sensors to observers and from controllers to actuators. Because data missing satisfies the Bernoulli distribution, such problem is transformed into an H ∞ control problem for stochastic switched delay systems. Average dwell time approach is used to obtain sufficient conditions on the solvability of such problems. A numerical example and a real example for water quality control are provided to illustrate the effectiveness and potential applications of the proposed techniques. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
103.
A few Ca-containing mono-metallofullerenes, i.e. Ca@C76, Ca@C88, Ca@C90 (I, II), were synthesized by an improved DC arc discharge method and isolated by a multi-stage HPLC method for the first time. These isomer-separated metallofullerenes were characterized by LD-TOF MS and UV-vis-NIR spectrometry. Their HOMO-LUMO band gaps and possible molecular geometries are discussed according to the absorption spectra in this report. In addition, the cyclic and differential pulse voltammetry of Ca@C76 was conducted in MeCN/C6H5CH3 (1:4 v/v). The voltammograms of Ca@C82 (II, III) and Ca@C84 (II) were also recorded. Their electrochemical behaviors are discussed compared with those of corresponding ytterbium metallofullerenes. The features of the Ca metallofullerenes’ electronic structures are also discussed. 相似文献
104.
发挥园区集群效应,借助中间介质回路将工业园区中各单厂内的余热于厂际间进一步回收利用,能够显著提高园区整体能源效率。其中,中间介质回路的设置与介质的选择将关系到整个余热回收系统的最优设计与节能效果。因此,不同于目前研究仅采用一种中间介质的集成策略,同时选用热水和导热油为介质开展厂际余热集成研究。提出耦合介质与厂内流股换热及介质流股在厂际间分配的换热器网络超结构,以年度总费用最小为目标建立MINLP热集成数学模型,优化获得包含介质回路结构与厂内换热器网络结构等内容的园区余热集成结果。最后,在一个包含3个厂的厂际余热集成案例中,分别研究了单种介质单回路、单种介质双回路及双种介质双回路3种情况,通过对比验证了所提方法的有效性。 相似文献
105.
106.
《Reactive and Functional Polymers》2007,67(10):865-882
Superabsorbent polymers of acrylamide (AAm)/crotonic acid (CA) were synthesized by foamed polymerization in an aqueous solution of AAm with CA as a comonomer, initiated by an initiator couple of ammonium persulfate and N,N,N′N′-tetramethylethylenediamine. A crosslinking agent N,N′-methylenebisacrylamide, a foaming agent sodium bicarbonate, and a foam stabilizer, a triblock copolymer of polyoxyethylene/polyoxypropylene/polyoxyethylene, were used in the polymerization. The influences of the relative contents of CA, crosslinking agent, and initiator, on the swelling properties of the superabsorbent polymer systems were examined. The superabsorbent polymer synthesized with an AAm/CA ratio of 98:2 by mole, 0.5 wt.% of N,N′-methylenebisacrylamide and 1 wt.% of ammonium persulfate at 250 rpm and 50 °C for 30 min of polymerization time produced the highest water absorption of 211 ± 9 times its dried weight and could absorb water up to 162 ± 4 g g−1 of the dry copolymer within 10 min. The electrochemical reaction for acrylamide–crotonic acid polymerization was investigated by cyclic voltammetry. The anodic current indicated that acrylamide acting as an electron donor whereas crotonic acid performed as an electron receiver, then providing the cathodic current. The diffusion of water into the superabsorbent polymer was non-Fickian (case II and anomalous). Acrylamide–crotonic acid superabsorbents containing various crosslinker concentrations had a water swelling in the range of 79–289 g g−1. The diffusion coefficients varied between 6.9 × 10−9 and 5.1 × 10−8 cm2 s−1. Adsorption of the basic dye by the superabsorbent was a monolayer evaluated by the Langmuir isotherm. The superabsorbents can thus be used to adsorb cationic dyes in textile industry. 相似文献
107.
《Catalysis communications》2007,8(11):1578-1582
In situ generation of H2O2 with high yield can be accomplished by reacting O2 with NH2OH from hydroxylammonium salt [NH2OH · HCl or (NH2OH)2 · H2SO4] in a neutral aqueous medium using a reusable heterogeneous Pd (1.0 wt%)/Al2O3 catalyst, even at low temperature (10 °C), with the formation of harmless by-products (viz. N2 and water). The presence of KCl or KBr in the medium has beneficial effect. The H2O2 generation is strongly influenced by the pH of medium, reaction period and temperature; best results are obtained at the optimum pH and reaction medium. 相似文献
108.
109.
基于流动平衡的塑料挤出模优化设计 总被引:1,自引:0,他引:1
在构建流道三维参数化模型的基础上,将有限元数值分析和优化技术相结合,以口模出口处型材截面上各子区域平均流速相等为优化目标,以压缩段入口壁厚和平直段长度为设计变量,对挤出模优化设计进行了研究。并以实例说明了优化设计的具体过程,验证了所用方法的正确性和有效性。 相似文献
110.
为研究预应力钢筋的锈蚀特性,在自然气候条件下,采用内掺盐的方式,进行了混凝土内钢绞线的锈蚀实验.实验结果表明:钢绞线的蚀坑形状可抽象为2种典型形状,即椭球形和马鞍形;随着锈蚀率增大,蚀坑总个数增大,椭球形蚀坑出现的概率呈先增后减趋势;马鞍形蚀坑出现概率呈先减后增趋势,但变化幅度都不大;蚀坑的长度、宽度、深度都较好地呈对数正态分布. 相似文献