A new analytical IGBT model with improved electricalcharacteristics

A new analytical insulated gate bipolar transistor (IGBT) model for improved on-state characteristics prediction is proposed. Two-dimensional (2-D) effects in the forward conduction of an IGBT are studied analytically. These effects significantly in8uence the on-state characteristics of the device and must be accounted for when IGBT modeling. Dynamic characteristics and temperature effects are included in the model. Both three-dimensional (3-D) numerical simulation and experimental results support the theoretical analysis     

Experiments on Vertical Turbulent Plane Jets in Water of Finite Depth

Detailed experiments on vertical turbulent plane jets in water of finite depth were carried out in a two-dimensional water tank. The jet velocities were measured with a laser Doppler velocimeter (LDV). The LDV measurement covers the entire flow regime: the zone of flow establishment (ZFE), the zone of established flow (ZEF), the zone of surface impingement (ZSI), and the zone of horizontal jets (ZHJ). From the experimental results, the following conclusions are reached. First, the jet flow is independent of the Reynolds number if the Reynolds number is sufficiently large to produce a turbulent jet. Second, in the initial ZFE, the jet flow is nonsimilar and is characterized by the two free shear layers along the two edges of the jet orifice. Third, the jet flow in ZEF is self-similar. Both mean and fluctuation velocities are scaled with the mean jet centerline velocity. The turbulent shear stress is predictable by Prandtl's third eddy viscosity model. The spreading of the confined vertical jets is larger than that of a free jet, so is the faster decay of jet centerline velocity. Fourth, in ZSI the jet flow is nonsimilar and high turbulent intensities were found. The vertical turbulent jet transforms into two opposite horizontal surface jets after the impingement. And finally, the maximum velocity of the horizontal surface jet in ZHJ decays according to a power law.     

特种硅铬合金冶炼工艺浅析

分析了二步法冶炼特种硅铬合金工艺对其出口合格率的影响因素，着重介绍也硅铬合金冶炼工艺的改进及其效果。     

专用螺栓冷挤压工艺及模具设计

对专用螺栓的冷挤压工艺进行了分析和计算 ,并介绍冲床冷挤压模的结构。     

99Tcm-DTPA-甲硝唑药盒的制备及初步临床应用

用氯化亚锡作还原剂,对ＤＴＰＡ－甲硝唑进行＾９９Ｔｃ＾ｍ标记,燕观察了试配比和反应条件对标记率的影响。在最佳标记条件下,其标记率〉９９％,并由此制成＾９９Ｔｃ＾ｍ－ＤＴＰＡ－甲硝唑药盒。     

心肌灌注显像剂99Tcm-Q3的制备方法学和药代动力学研究

采用正交实验筛选法制备＾９９Ｔｃ＾ｍ－Ｑ３（＾９９Ｔｃ＾ｍ－Ｎ,Ｎ－’亚乙基－二（乙酰丙酮亚胺）二「三（３－甲氧基－１－丙基）膦」）;家兔注射＾９９Ｔｃ＾ｍ－Ｑ３后定时采血,绘制血药时间－放射性曲线并分析其体内药代动力学。结果显示,制备＾９９Ｔｃ＾ｍ－Ｑ３的最佳配方为ＫＯＨ溶液３０μＬ,ＳｎＣｌ２．２Ｈ２Ｏ溶液２０μＬ,Ｎ,Ｎ‘－亚乙基－二（乙酰丙酮亚胺）２０ｍｇ和三（２－甲摒在０－１－丙基）膦５     

机械手臂旋转系统中步进电动机驱动线路的设计

阐明新型步进电动机驱动线路各个部分的功能、特点及其整个系统的线路组成     

地球化学反演——东秦岭两类不同古地幔成分的确定

应用东秦岭丹凤岛弧火成岩系对早古生代地幔和应用商丹断裂中松树沟残余橄榄岩系对元古宙原始地幔进行了化学成分反演,结果显示:元古宙地幔较古生代地幔更加富集不相容元素,而贫乏相对相容元素。反映在壳幔的分异过程中,不相容元素在地壳中逐渐富集,而在地幔中不断贫乏。     

极大理想环及其Grothendieck群

重新定义了极大理想环,确定了Grothendieck群,从而推广了[3]的结果,另外还指出了[3]的错误。