无横梁高刚性轧机的结构分析

本文介绍了无横梁高刚性轧机的新颖结构，分析了该轧机高刚性及轴承长寿的原理。该轧机在现场使用中，取得了良好的效果。     

EFFECTS OF COLD EXPANSION OF A HOLE ON FATIGUE CRACK INITIATION LOCATION AND LIFE OF AN LY12CZ ALLOY

Abstract— In the present study the effects of cold expansion of a hole on the location of fatigue crack initiation and life of LY12CZ alloy sheets are experimentally investigated and a quantitative expression of fatigue crack initiation life presented. Test results and analysis show that there may exist an optimum amount of cold expansion, for which both the coefficient of the resistance to fatigue crack initiation and the threshold are increased, and that the direction of cold expansion has no appreciable effect on fatigue crack initiation life. Observations show that, after cold expansion the fatigue crack nearly always initiates on the final entry face from which the mandrel is introduced into the hole during the final cold expansion process. Therefore it may be thought that the entry face is less resistant to fatigue crack initiation. In addition, the assumption of equivalence of residual stresses and also the strain hardening conditions on both the entry and exit faces may be questionable.     

Gate and drain currents in off-state buried-type p-channel LDDMOSFETs

The buried-type p-channel LDD MOSFETs biased at high positive gate voltage exhibit novel characteristics: (1) the ratio of the drain to gate currents is about 1×10^-3 to 5×10^-3; and (2) the gate and drain currents both are functions of only the gate voltage minus the n-well bias. Such characteristics are addressed based on the formation of the surface n ⁺ inversion layer due to the punchthrough of the buried channel to the underlying shallow p-n junction. The measured gate current is due to the Fowler-Nordheim tunneling of electrons from this inversion layer surface and the holes generated within the high-field oxide constitute the drain current. The n⁺ inversion layer surface potential is found to be equal to the n-well bias plus 0.55 V. As a result, both the oxide field and the gate and drain currents are independent of drain voltage     

红外警戒系统的运动参数估计算法

通过对目标飞行轨迹的参数化建模，提出了由红外传感器对目标角度和辐射功率的测量实现对目标距离和其它位置、速度参数估计的算法，从而可以此作为目标威胁程度估计和目标特性识别的依据。仿真计算表明，该方法计算的精度高，对目标位置的初始先验值依赖程度较小。该算法也适合于其它测量体制的目标运动参数估计。     

改进遗传算法在电力系统无功优化中的应用

针对常规遗传算法（GA）的不足,提出了一种改进搜索策略的遗传算法,采取了以下改进措施：在遗传迭代中,根据种群进化过程的个体的适应值大小,对群体进行分级,对级别高的个体进行小范围的搜索,对级别低的个体在大范围内进行搜索,保证群体的多样性的同时,又留住了优良个体。将改进的遗传算法应用于电力系统无功优化,并与常规遗传算法进行了比较,结果表明改进算法在计算速度、收敛性和全局最优搜索能力都有提高。     

圆环扫描速高比计研究

介绍了圆环扫描速高比计(V/H计)的工作原理。给出了理论分析和实验结果。讨论了影响精度的原因和今后改进的方法。     

基于雅可比矩阵的电压控制区域划分的改进

对应用比较广泛的电压控制区域（VCA）划分方法进行了改进，在传统的去除小元素法基础上，采用牛顿 — 拉夫逊法潮流雅可比矩阵中有功和无功对电压幅值偏导数的子矩阵之和进行VCA划分;然后，将各种拓扑变化对系统电压稳定性的影响进行排序，按从大到小的顺序用这些拓扑变化对得到的VCA分区进行修正，直到修正结果不再改变为止，从而得到了适用于各种拓扑结构下电压稳定性分析的分区。改进后分区的有效性在新英格兰10机39节点系统上得到了验证。     

多绳摩擦提升机提升钢丝绳张力平衡问题分析

对张力自动平衡问题进行分析,结合张力不平衡的力学分析探讨提升钢丝绳张力平衡问题。且对一种张力自动平衡悬挂装置的结构、原理、特点进行介绍,了解张力平衡的总的特点和性能。     

AVO反演预处理中的检波器非径向接收能量补偿.

 在地震勘探中，当炮检距非零时，检波器接收方向与反射波传播方向的夹角是非零的（即非径向接收），这一非零夹角必将产生能量损失，进而对AVO反演产生显著影响。为此本文根据Snell定律导出非径向损失补偿公式，以模型实例讨论了非径向接收对反射系数的影响，并提出了一种简单而有效的非径向能量损失补偿方法。对比用该方法做非径向损失补偿前后的AVO反演结果，其差异显著，说明本文方法能够明显改善AVO反演的质量。     

一种新型半桥不对称PW M控制变换器

介绍了一种适用于DC／DC半桥变换的不对称PWM控制方案，分析了电路的工作原理，给出了150W变换器的仿真波形和实验结论，结果表明，该控制方案能在恒定开关频率下对变换器实现高效率的软开关控制。