A new colloidal precursor cooperative conversion route to nanocrystalline quaternary copper sulfide

A novel milk-like Cu-thiourea colloid has been synthesized. Nanocrystalline quaternary copper sulfide Cu₂FeSnS₄ was obtained through the Cu-thiourea colloidal precursor cooperative conversion route at low temperature. The samples were characterized by means of X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and X-ray energy dispersive spectroscopy techniques. The reaction details and features were described and discussed.     

Electrical conductivity and gas sensitivity of Zn-Sb-O thick films

The thick film of Zn-Sb-O was prepared by coating the paste of nanoparticles mixture (Sb₂O₃:ZnO=1:3) on the alumina substrate, followed by sintering at 500-900 °C for 2 h in air. The electrical resistance and gas-sensing properties to benzene, alcohol and acetone of Zn-Sb-O films were found to be dependent on the change of phase structure caused by sintering temperature.     

钢筋砼结构可靠度的研究

本文简要介绍钢筋砼结构可靠度分析方法、砼与钢筋设计强度取值及抗力计算公式的合理化。     

月桂醇聚氧乙烯醚硝酸酯助燃降污性能的研究

通过柴油发动机台架试验证明 ,月桂醇聚氧乙烯醚硝酸酯用作柴油添加剂 ,既可提高柴油的燃烧性能 ,又可降低排放尾气中的一氧化碳 (CO)、未燃碳氢化合物 (HC)、氮氧化物 (NOx)含量及烟度等多种功能 ,是一种良好的多功能柴油助燃消烟添加剂。     

论剪切质量的提高

通过对飞剪剪切长度，精度，剪刃间隙和压板机构等参数的优化，来提高钢板的剪切质量。     

从实际出发 探索办学理念

从学生、社会、学校、教师和学科诸多方面探索办学理念.提出通过学科、专业、课程、教学方法、考核方式等的改革,培养工商企业所需的有较高素质和发展潜力的人才.     

Stability robustness of networked control systems with respect to packet loss

This paper is concerned with stability analysis of discrete-time networked control systems over a communication channel subject to packet loss whose behavior is modeled by an i.i.d Bernoulli process with a packet dropping probability bounded by a constant. A necessary and sufficient condition for stability is obtained. A packet dropping margin is introduced as a measure of stability robustness of a system against packet dropping, and a formula for it is derived. A design method is proposed for achieving a large margin subject to a constraint that the system has a set of prescribed nominal closed-loop poles.     

Local residence time,residence revolution,and residence volume distributions in twin‐screw extruders

This work was aimed at studying the overall, partial, and local residence time distributions (RTD); overall, partial and local residence revolution distributions (RRD) and overall, partial and local residence volume distributions (RVD) in a co‐rotating twin screw extruder, on the one hand; and establishing the relationships among them, on the other hand. Emphasis was placed on the effects of the type and geometry of mixing elements (a gear block and various types of kneading elements differing in staggering angle) and process parameters on the RTD, RRD and RVD. The overall and partial RTD were directly measured in‐line during the extrusion process and the local ones were calculated by deconvolution based on a statistical theory. The local RTD allowed comparing the mixing performance of mixing elements. Also it was confirmed both experimentally and theoretically that specific throughput, defined as a ratio of throughput (Q) over screw speed (N), controlled all the above three types of residence distributions, be they local, partial or overall. The RRD and RVD do not provide more information on an extrusion process than the corresponding RTD. Rather they are different ways of representing the same phenomena. POLYM. ENG. SCI., 48:19–28, 2008. © 2007 Society of Plastics Engineers     

负载型固体碱催化合成亚苄基丙酮

研究了用固体碱 KOH/Al_2O_3催化合成苯叉丙酮,确定了合成的最佳工艺条件:n(苯甲醛)∶n(丙酮)=1∶4.催化剂用量2g,催化剂最佳负载量12mmol/g,反应温度40～45℃,反应时间为3h,产率达88%以上。     

从全球风电产业发展大势看破解我国缺电难题的新途径

我国能源紧缺，电力供应紧张，已是制约国民经济持续稳定发展的棘手难题。报载我国各省区电力供应缺口达2500万kW，其中仅广东省就缺电600万kW。为破解缺电难题，增加煤、石油和天然气等化石燃料的生产或进口、规划建设数十座核电站、加快国内主要以煤为燃料的电厂建设、兴建大型水电站等都是选项，尤其是加快风电产业发展可让风电为解决我国缺电难题助一臂之力，笔者试就此问题发表一点个人看法。