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基于时域响应灵敏度分析的非线性系统参数识别 被引量:7
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作者 刘广 刘济科 吕中荣 《振动与冲击》 EI CSCD 北大核心 2018年第21期213-219,共7页
基于响应灵敏度分析的有限元模型修正法已广泛应用于线性结构系统的局部损伤和裂纹参数等的识别。尝试将该方法推广应用到非线性系统的参数识别中。从非线性系统运动方程出发,通过数值积分得到系统的强迫振动响应,对系统的物理参数求导... 基于响应灵敏度分析的有限元模型修正法已广泛应用于线性结构系统的局部损伤和裂纹参数等的识别。尝试将该方法推广应用到非线性系统的参数识别中。从非线性系统运动方程出发,通过数值积分得到系统的强迫振动响应,对系统的物理参数求导得到时域响应对参数的灵敏度,从而构造相应的响应灵敏度矩阵用于参数识别反问题。以Holmes-Duffing非线性系统和物理工程中有着广泛应用的双重sine Gordon非线性系统的参数识别为例,说明方法的应用过程。算例研究了不同的初始参数和测量噪声对识别结果的影响,结果表明响应灵敏度法能准确快速识别非线性系统的参数,并且具有对测量噪声不敏感的优点。 展开更多
关键词 参数识别 非线性系统 灵敏分析 Holmes-Duffing系统 双重sine Gordon系统
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线性规划联合算法的理论与应用 被引量:11
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作者 夏少刚 《运筹与管理》 CSCD 2004年第1期11-16,共6页
本文在[1]的基础上,较系统的叙述了线性规划联合算法的步骤、相关理论及其应用,指出该算法具有避免人工变量、减少迭代次数、使用灵活、应用方便等特点。
关键词 线性规划 联合算法 对偶单纯形 单纯形法 灵敏应分析
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Rifaximin vs conventional oral therapy for hepatic encephalopathy:A meta-analysis 被引量:9
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作者 Karim M Eltawil Marie Laryea +1 位作者 Kevork Peltekian Michele Molinari 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第8期767-777,共11页
AIM: To characterize the efficacy of rifaximin in the management of hepatic encephalopathy (HE) as several randomized controlled studies have shown contradictory results on its effectiveness in comparison to other ora... AIM: To characterize the efficacy of rifaximin in the management of hepatic encephalopathy (HE) as several randomized controlled studies have shown contradictory results on its effectiveness in comparison to other oral agents. METHODS: We performed a systematic review and random effects meta-analysis of all eligible trials identifi ed through electronic and manual searches. Twelve randomized controlled trials met the inclusion criteria with a total of 565 patients. RESULTS: The clinical effectiveness of rifaximin was equivalent to disaccharides or other oral antibiotics[odds ratio (OR) 0.96; 95% CI: 0.94-4.08] but with a better safety profi le (OR 0.27; 95% CI: 0.12-0.59). At the completion of treatment protocols, patients receiving rifaximin showed lower serum ammonia levels [weighted mean difference (WMD) = -10.65; 95% CI: -23.4-2.1; P = 0.10], better mental status (WMD = -0.24; 95% CI: -0.57-0.08; P = 0.15) and less asterixis (WMD -0.1; 95% CI -0.26-0.07; P = 0.25) without reaching statistical signifi cance. On the other hand, other psychometric outcomes such as electroencephalographic response and grades of portosystemic encephalopathy were superior in patients treated with rifaximin in comparison to the control group (WMD = 0.21, 95% CI: -0.33-0.09, P = 0.0004; and WMD = -2.33, 95% CI: -2.68-1.98, P = 0.00001, respectively). Subgroup and sensitivity analysis did not show any signifi cant difference in the above fi ndings. CONCLUSION: Rifaximin appears to be at least as effective as other conventional oral agents for the treatment of HE with a better safety profi le. 展开更多
关键词 Hepatic encephalopathy LACTULOSE Neo-mycin Non-absorbable disaccharides RIFAXIMIN
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Methodology for Precious Metal Recovery in Computer Printed Circuit
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作者 Miguel Aguilar Cortest Martha Lilia Dominguez Patifio +2 位作者 Antonio Rodriguez Martinez Rene Guardian Tapia Rosa Maria Melgoza Aleman 《Journal of Chemistry and Chemical Engineering》 2013年第8期759-766,共8页
The life of electronic equipment is becoming increasingly shorter and its replacement always generates a quantity of waste increase, giving rise to a problem of environmental character and still needed new options of ... The life of electronic equipment is becoming increasingly shorter and its replacement always generates a quantity of waste increase, giving rise to a problem of environmental character and still needed new options of solid waste management that will contribute to global sustainable development. Parts of these waste are TCI (the card's printed circuit) which containing dangerous elements and turns them into a polluting material from the soil, water and air, being harmful to human health if there is to proper and responsible way, so the recycling of TCI to obtain precious metals is an example of industrial materials that can be recycled. Despite this, large quantities of these are not recycled and some others are not considered. The objective of this work is to present a systematic and ecological methodology for the recovery of valuable materials contained in parts of used in computers, circuit boards using a leaching process. The method determines a set of variables to evaluate the kinetics of the reaction and the leaching of metals that form the substrate of metal and to establish the parameters that affect the rate of leaching of metals through a sensitivity analysis, to identify design alternatives. It determines the quantity and percentages that constitutes the motherboard, processor, video cards, accelerator graphics, network and memory cards RAM, among others and its content of metals such as Cu, Fe, Ag, Au and Pt. 展开更多
关键词 Precious metals LEACHING waste electrical and electronic equipment printed circuit board.
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