Improved stability conditions for systems with interval time-varying delay

The paper is concerned with the stability of linear systems with interval time-varying delay. Through constructing a new augmented Lyapunov-Krasovskii functional (LKF) which contains some quadruple-integral terms and estimating the time derivative of the LKF less conservatively, new stability criteria are derived without introducing any free matrices. Moreover, by proving the positive definiteness of the LKF with some integral inequalities, the constraints on some functional parameters are relaxed and the conservatism of the obtained results are further reduced. Numerical examples are also given to demonstrate the effectiveness and reduced conservatism of the obtained results.     

人群头发元素分布及某些特征研究

本文介绍用堆中子活化分析法测定人群头发中I、Br、Mg、Mn、Cu、Na、V、Cl、Al、Ca、S等11种元素。研究人发中元素分布特征、相关性特征、性别年令分布特征。方法学中还从法庭科学应用角度介绍同一性识别中差异率和重合几率的双判据方法。     

结晶器液压振动技术在梅山高效连铸中的应用

为了得到较好的铸坯表面质量,满足生产高附加值、高技术含量的钢种要求,梅山炼钢厂在2#高效连铸机上引进了国际上较先进的结晶器液压振动技术,具体介绍了该结晶器液压振动技术的基本参数和实际应用。     

PC／PA1010共混物的热行为

利用热失重、微分热失重和显示扫描量热法研究了聚碳酸酯／尼龙１０１０共混物的热行为和解降解过程。结果表明：共混物在６００℃以下分两步降解，降解温度随尼龙１０１０用量增加有下降趋势；共混物的熔点随尼龙１０１０用量增加而升高。     

自密封阀在氨汽提尿素装置中的应用与维修

介绍自密封阀的密封原理及其在氨汽提尿素装置中的应用,对其长期运行中出现的泄漏及泄漏原因进行分析,根据不同的泄漏方式分别提出了现场维修的方法.     

甲基葡萄糖甙（MeG）水溶液工艺改进试验

介绍了用５次以上的母液生产ＭｅＧ水溶液工艺的改进试验。     

Study of collective user behaviour in Twitter: a fuzzy approach

The study of collective user behaviours in social networking sites has become an increasing important topic in social media mining. Understanding such behaviours has its potential to extract actionable patterns that can be beneficial to develop effective marketing strategies, optimise user experiences and maximise website revenues. With the rapid development of micro-blogging, Twitter has become a richer source of intelligence that can be used to study collective user behaviour, due to its efficient and meaningful user-to-user interactions. However, the classical statistical methods have some drawbacks in bridging the gap between user-generated data and human analysts who mostly use linguistic terms to analyse data and model/summarise knowledge learned. To address this gap, this work proposes a new approach, which employs the mass assignment theory-based fuzzy association rules algorithm (MASS-FARM), for the first time, to extract useful interaction behaviour of Twitter users. The influential factors (including activity time, number of friends/followers and the number of tweets) are represented as fuzzy granules, and the associations amongst are studied by employing MASS-FARM. The collective user behaviours are analysed in the Reply category and the Non-Reply category, respectively. The applicability and usefulness of the proposed method are demonstrated via an empirical study on a collected Twitter data set. The derived results are also discussed and compared with existing works.     

Preparation of Titanium Nitride/Alumina Laminate Composites

A preparation route for TiN/Al₂O₃ laminate composites has been described. A water-based process using Al₂O₃ and TiN slurries with solids contents of 40 and 35 vol%, respectively, was used to make TiN and Al₂O₃ tapes. The removal of the binder was monitored by weight-loss measurements in a thermogravimetry unit. Bodies composed of Al₂O₃ and TiN tapes were densified at temperatures of 1400° and 1500°C using the Spark Plasma Sintering^® (SPS) technique. Densities of >98% of the theoretical densities were approached. Crack-free and almost fully densified TiN/Al₂O₃ compacts were prepared by heating the burned-out green bodies to the final sintering temperature (1500°C) at a rate of 100°C/min, and with a holding time of 5–10 min, under a pressure of 75 MPa. The microstructures of the obtained compacts were studied using scanning electron microscopy. Grain sizes in the sintered Al₂O₃ and TiN compacts were similar to those of the precursor powders. Hardness and indentation fracture toughness were measured at room temperature, and the monolithic compacts as well as the laminate composites exhibited anisotropic mechanical behavior; i.e., the cracks propagated much more easily in a direction parallel to the laminas than perpendicular to them.     

吊车断裂弹簧钢板的焊接修复

吊车上的板弹簧是一个很重要的零件,它在反复应力下工作,承受较大的冲击负荷和振动,要求其应具有较高的疲劳强度、抗拉强度等性能。由于板弹簧为碳含量较高的合金钢,焊接性差,修复断裂的板弹簧较困难。某公司的一台日本进口TL-252型25t吊车,在使用二年内先后发现五块弹簧钢板断裂,给现场施工带来了不便和一定的经济损失。经制定严格的工艺,对断裂板弹簧成功地进行了焊接修复,修复后使用效果很好。1板簧材料及可焊性分析断裂的弹簧钢板为日本钢号SUP6,相当于我国的60Si2Mn弹簧钢,其化学成份见表1。表1SUP6钢的化学成份(%)C Si Mn S P …