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     

状如琼，凝为脂

在我们喝的饮料粒粒橙中，为什么那些细小的橙子颗粒是悬浮在橙汁中的呢？果冻和布丁为什么是透明，且柔软有弹性的呢？去看看成分表，我们不难发现共同之处，看似不同的食品都添加了一种共同的成分——琼脂。[编者按]     

负载型固体催化剂在生物柴油制备中的研究现状及应用前景

对生物柴油及其制备方法进行简单介绍，重点综述了负载型固体酸、碱催化剂在生物柴油制备中的研究现状，并指出当前负载型固体催化剂研制中的研究热点，最后对其应用前景了进行展望。     

用VB解决CAI中的几个问题

本文利用Windows的API函数将VB窗体前置,避免教师在CAI过程中频繁切换活动窗口,并通过VB控件将各种不同的电子文档内容在窗体中显示出来。     

MIP-CGP工艺专用催化剂CGP-1的开发与应用

阐述了生产汽油组分满足欧Ⅲ排放标准并多产丙烯的催化裂化工艺（简称MIP-CGP）专用催化剂（简称CGP-1）的研究开发与工业应用结果。CGP-1催化剂的基质具有良好的容炭性能，使活性组元受到良好保护，其优势作用在第二反应区得以充分发挥，具有更高的氢转移活性和强的汽油小分子烯烃裂化活性。中国石化九江分公司和镇海炼化公司的MIP-CGP工业试验标定结果表明，与常规FCC相比，采用CGP-1催化剂的MIP-CGP技术在生产烯烃体积分数小于18％的汽油组分的同时，丙烯产率达到8％以上。此外，汽油诱导期大幅提高，抗爆指数增加；总液体收率有所提高，干气产率下降，焦炭选择性良好。     

基于作业测定技术的后桥壳生产线工艺评价及优化

以某企业后桥壳生产线为研究对象,运用作业测定技术中的时间研究法,测定后桥壳各工序的标准时间,评价工艺及找到瓶颈工序;运用"5W1H"提问技术,根据"ECRS"原则,同时结合工艺设计及企业资源情况,对后桥壳生产线现有工艺进行评价及优化,改善后,使生产线的产能每天提高了10件,生产能力提高了33.57%.     

Global Asymptotical Synchronization of Chaotic Lur'e Systems Using Sampled Data: A Linear Matrix Inequality Approach

Sampled-data feedback control for master-slave synchronization schemes that consist of identical chaotic Lur'e systems is studied. Sufficient conditions for global asymptotic synchronization of such chaotic Lur'e systems are obtained using the free-weighting matrix approach and expressed in terms of linear matrix inequalities (LMIs). With the help of the LMI solvers, the sampled-data feedback control law can easily be obtained to globally asymptotically synchronize Lur'e chaotic systems. The effectiveness of the proposed method is finally illustrated via numerical simulations of chaotic Chua's circuits.     

探讨某高级车库设计需要注意的几点问题

广州市现在每天增加的小汽车数量就在400辆以上，这种迅猛的增长势头除了对城市的交通运输网络造成很大的压力外，城市的停车缺口也在不断扩大，现在广州市的停车位缺口就在30万辆左右。针对这种情况，地方政府正在加大解决城市停车难问题的力度．其中一项措施就是增加建设停车库。