基于混沌离散PSO算法的乙烯生产过程模型变量的选择

管式炉裂解技术是当今乙烯生产的主要技术,乙烯生产过程中有多种影响质量指标的变量,将全部变量参与建模显然会增加建模难度和复杂性,并且大量的冗余信息会降低模型的精度;针对这一问题,提出了基于混沌思想的离散粒子群(PSO)算法进行模型变量的选择;首先,采用混沌离散PSO算法得到建模的最优输入变量集合,再通过偏最小二乘法(PLS)对所选变量进行建模;结果表明,该方法可更有效地克服传统粒子群算法容易陷入局部最优的问题并建立较高的模型精度。     

Recent results for single meson production from the Crystal-Barrel/TAPS experiment at ELSA

The present focus of the CBELSA/TAPS experiment is on meson-photoproduction off the nucleon using polarized photons and polarized targets. Here first preliminary results on the reactions γp → pπ and γp → pπ for both circularly and linearly polarized photons and a longitudinally polarized target are presented. Preliminary results for the beam asymmetry ∑ and the double polarization observable G have been extracted for both reactions using the linear polarization data. From the circular polarization data the observable E has been determined. Due to the near 4π angular coverage of the detector system these results cover almost the full solid angle.     

如何提高热机效率教学问题的探讨

在物理教学中研究如何提高热机效率问题,具有实际意义．1热机效率在生产技术中,需要将热与功之间的转换持续的进行下去,这就需要用到循环过程．能够实现热功转换过程的装置叫热机．热机效率是热机效能的一个重要标誌,即热力学系统从     

物理实验的引用和实验器材的使用

许多物理教材中,在引入某一个新概念时经常会举出几个甚至更多与此相关的生活、生产和科技实例,以此证明、烘托这个概念的正确性和重要性．这种教法对于学生接受并理解一个新概念有十分必要也十分有效,但在教学过程中,我发现仅用此法也容易使学生产生错觉和误解：这些事例、这些器材只能作此用途,从而不利于学生进行发散性思维和创造性思维．所以,应该尽可能利用学生熟悉的事物来认知未知的事物．为此,我在教学过程中作了一些尝试和比较．     

碳排放与资金双重约束下企业存货质押与生产决策

在碳排放许可与交易制度下,研究受资金约束的排放依赖性企业的存货质押与生产决策.以利润函数为目标函数构建决策模型,模型包括销售收入、生产成本、产成品存储费用、缺货成本、贷款利息、排放权市场交易费用和净化成本.通过求解,得出质押量、产量及对应的利润,最后对各参数进行敏感性分析.     

螯合树脂交换——光度法测定氯化钠溶液中微量镁

研究了用螯合树脂交换分离富集氯化钠溶液中微量镁及吸光光度法测定镁含量的方法。回收率为９６．０－１０１．０％，在ＰＨ１０的硼砂－氢氧化钠介质中，镁含量在０－１２μｇ／２５ｍｌ范围内符合比耳定律。方法稳定性高、重现性好。     

稀土绿色冶金及应用技术研讨会暨第十届全国稀土化学与湿法冶金学术会议(征文通知)

中国广西北海2011年9月25日～27日主办单位:中国工程院化工、冶金与材料工程学部/中国稀土学会承办单位:中国铝业公司/广西有色金属集团协办单位:北京有色金属研究总院/稀土材料国家工程研究中心支持单位:国家发展和改革委员会/国家工业和信息化部/国家科技部/中国稀土行业协会(筹)/广西壮族自治区科技厅/中国有色金属工业协会稀土是当今世界各国发展高新技术和国防尖端技术、改造传统产业不可缺少的战略物资。我国稀土资源储量大,分布广,矿物种类齐全。经过50多年的发展,我国建立了较完整的稀土产业链和工业体系,并发展成为世界稀土生产、出口和消费大国,在世界上具有举足轻重的地位。但随着我国稀土工业的快速发     

Effect of Polysaccharides from Fruit Body of Ganoderma tsugae on Bidirectional Regulation of Proinflammatory Cytokine Production in THP-1 Cells

The polysaccharides,FIII-2,FIII-2-a,FIII-2-b and FIII-2-c were purified from the fruit body of Ganoderma tsugae(G.tsugae) to study the effects of the four polysaccharides on the productions of human proinflammatory cytokines,interleukin-1α(IL-1α) and tumor necrosis factor α(TNFα).The results show that the polysaccharides up-regulated the production of IL-1α and TNFα in THP-1 cells under non-stimulatory condition or under stimulation of both lower concentration lipopolysaccharide(LPS) and phorbol myristate a...     

A novel correlation for estimation of hydrate forming condition of natural gases

An inherent problem with natural gas production or transmission is the formation of gas hydrates, which can lead to safety hazards to production/ transportation systems and to substantial economic risks. Therefore, an understanding of conditions where hydrates form is necessary to overcome hydrate related issues. Over the years, several models requiring more complicated and longer computations have been proposed for the prediction of hydrate formation conditions of natural gases. For these reasons, it is essential to develop a reliable and simple-to-use method for oil and gas practitioners. The purpose of this study is to formulate a novel empirical correlation for rapid estimation of hydrate formation condition of sweet natural gases. The developed correlation holds for wide range of temperatures (265–298 K), pressures (1200 to 40000 kPa) and molecular weights (16−29). New proposed correlation shows consistently accurate results across proposed pressure, temperature and molecular weight ranges. This consistency could not be matched by any of the widely accepted existing correlations within the investigated range. For all conditions, new correlation showed average absolute deviation to be less than 0.2% and provided much better results than the widely accepted existing correlations.     

中国稀土控股有限公司

中国稀土控股有限公司为全国超大规模的稀土及耐火材料生产商之一。公司于一九九九年十月十五日在香港联交所上市（名称：中国稀土,代码：0769）,是中国在海外上市的私有稀土和耐火材料生产企业？