Numerical modeling of gate turn-off thyristor using SICOS

A numerical model of gate turn-off thyristors (GTOs) is presented. The concept of a controlled switch realized by a controlled current source is first introduced. Using this basic model, an equivalent circuit for the GTO is given. Using the GTO characteristics given by manufacturers, the equations connected with all the parameters of the equivalent circuit are deduced, and all of the parameters are determined. A sample study is presented. Simulation of this numerical model with the SICOS program gave results in accordance with the experiment     

鲁棒渐近跟踪控制器设计的新方法

对于线性不确定系统,本文基于Riccati方程的正定解提出一种设计鲁棒渐近跟踪控制 器的新方法.所设计的控制器,对于所有允许的系统参数变化,均使系统输出渐近跟踪某一参 考输入.这种方法的特点是设计简单、实现方便.     

Neurovirulence in feline immunodeficiency virus-infected neonatal cats is viral strain specific and dependent on systemic immune suppression

Feline immunodeficiency virus (FIV) is a lentivirus that causes immune suppression and neurological disease in cats. Among animal viruses, individual viral strains have been shown to be neurovirulent, but the role of viral strain specificity among lentiviruses and its relationship to systemic immune suppression in the development of neurological disease remains uncertain. To determine the extent to which different FIV strains caused neurological disease, FIV V1CSF and Petaluma were compared in ex vivo assays and in vivo. Both viruses infected and replicated in macrophage and mixed glial cell cultures at similar levels, but V1CSF induced significantly greater neuronal death than Petaluma in a neurotoxicity assay. V1CSF-infected animals showed significant neurodevelopmental delay compared to the Petaluma-infected and uninfected animals. Magnetic resonance spectroscopy studies of frontal cortex revealed significantly reduced N-acetyl aspartate/creatine ratios in the V1CSF group compared to the other groups. Cyclosporin A treatment of Petaluma-infected animals caused neurodevelopmental delay and reduced N-acetyl aspartate/creatine ratios in the brain. Reduced CD4(+) and CD8(+) cell counts were observed in the V1CSF-infected group compared to the uninfected and Petaluma-infected groups. These findings suggest that neurodevelopmental delay and neuronal injury is FIV strain specific but that systemic immune suppression is also an important determinant of FIV-induced neurovirulence.     

真空熔烧涂层与母材的界面研究

采用法向拉伸法测定了真空熔烧涂层与母材的界面结合强度 ,并用电子探针分析了合金元素沿层深分布情况。结果表明 ,真空熔烧法制得的涂层与母材间形成了牢固的冶金结合 ,界面结合强度可达 3 60～40 0MPa ,提高了材料的抗热疲劳性能。合金元素在界面两侧的扩散是影响材料显微组织、显微硬度及界面结合强度的关键     

Effect of Ce on the Aging of AlMgSi Alloy by Resistance Measurement

ＥｆｆｅｃｔｏｆＣｅｏｎｔｈｅＡｇｉｎｇｏｆＡｌＭｇＳｉＡｌｌｏｙｂｙＲｅｓｉｓｔａｎｃｅＭｅａｓｕｒｅｍｅｎｔ￥ＸｕＹｕｅｈｕａｎｇ（徐约黄），ＷａｎｇＳｈａｏｌｉｎｇ（王绍苓），ＴｉａｎＳｈａ（田沙），ＤｕＦｅｎｇｍｕ（杜凤牡），ＺｈｏｕＸｉａｏ...     

振动时效在刺绣机机架加工中的应用

本文基于现场试验 ,简要介绍了振动时效 (VSR)在刺绣机机架应用过程中的一些技术要点和振动参数设定 ,并根据JB/T5 92 6— 91中相关的VSR效果评定标准论证了本次试验方案的可行性 ;同时 ,本文将动应力测量法引入VSR效果评定中 ,并与其它方法相比较。结果表明通过动应力测量来进行VSR效果评定具有便捷、定量、经济的优点 ,是一种应用性技术。     

先进控制技术在常减压装置的应用

介绍了先进控制技术在兰州石化公司5Mt／a常减压装置上的应用情况，阐述了控制器开发过程的要点。通过采用多变量控制手段来实现工艺控制目的，不仅提高了装置的运行平稳率，而且能够卡边进行操作，达到了提高目标产品收率和装置节能降耗的目的。     

改性PZT95/5材料的介电性能研究

根据同化合价,不同离子半径;相近离子半径,不同化合价的原则选择氧化物对PZT95/5(PbZr0.95Ti0.05O3)进行分别掺杂,研究了碱金属族、碱土金属族氧化物,及Fe、Si、Nb、W等的氧化物掺杂对PZT95/5材料的介电常数、介电损耗的影响。研究发现一价、二价金属离子的掺杂除Mg外都使得材料的介电常数、介质损耗有不同程度的下降,一价掺杂使得介电常数随掺杂物离子半径增大而减小,二价掺杂随离子半径的增大使得介电常数有增大的趋势。高价金属离子如Fe3+、Si4+、Nb5+等的掺杂使得材料具有比一价、二价掺杂更高的介电常数和损耗。     

复合乳化体系在甲基丙烯酸甲酯/丙烯酸丁酯细乳液共聚合中的应用

用两性离子型乳化剂十二烷基磺基甜菜碱(DSB)和阴离子型乳化剂十二烷基硫酸钠(SDS)复配,作为甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)细乳液共聚体系的复合乳化剂,以十六醇作为助稳定剂,得到了稳定的聚合物理乳液,其乳胶粒径为100~150 nm。考察了复合乳化剂的浓度及配比对单体转化率、所得聚合物相对分子质量、乳胶粒径大小的影响。实验结果表明,在w(DSB)=0.14％的条件下,聚合反应速率和产物最终转化率出现极大值;与纯SDS乳化体系相比,复配乳化体系的聚合反应速率和乳液最终转化率较低;对聚合物胶乳的粒子的均匀程度略有影响;DSB用量增加,产物相对分子质量变大。     

小断块高凝油藏高效开发经验

位于黄骅坳陷小集断裂带的官９３８断块油藏采出程度已经达４３．９％，预测最终采收率可达５７％。该油藏油层多且厚，属高凝中低渗油藏，总结该断块成功开发经验，可对同类油藏的开发提供借鉴。该断块油层虽厚但层数多，非均质性较强，在开发前期就采取分层开采方案，运用原油的粘温关系、排量和井口温度关系，采用大排量生产的方法解决了原油凝固点高的问题；在地层压力下降后，及时注水补充能量，结合先进的工艺，进行层间调剖；在开发后期，开展数值模拟和精细油藏描述，反复认识注水过程中剩余油运移及分布规律，再次调整，开展层间挖潜，实现了油层均匀动用。图２表３（郭海莉摘