接地网故障诊断的一种新方法

提出一种无伤诊断接地网故障的新方法.首先提出并证明了利用接地网的可及点电压值检测接地网故障的判据,然后应用网络撕裂法概念建立接地网区域故障的诊断方程.模拟仿真诊断结果表明,这种诊断方法是正确而有效的,它可以用于电力系统接地网的故障诊断.     

节点撕裂信号流图法

将电路的节点撕裂法引入信号流图法，两者有机的结合，使信号流图法能分析规模较大的电路与系统，进一步扩大了信号流图进行符合分析的独特功能和应用范围，并提高了分析速度。     

Effect of Ce addition on hot tearing behavior of AZ91 alloy

A small amount of cerium (below 1.0 wt%) addition to AZ91 alloy have been investigated on the hot tearing susceptibility (HTS) at a cooling rate of 1.5Ks^?1. The HTS increased to a maximum value with a cerium addition of 0.6 wt% and then decreased to a stable status as cerium was gradually added. Due to high chemical activity, cerium into the melts can react with aluminum to form an Al₁₁Ce₃ intermetallic compound. X–ray diffraction results also confirmed the existence of Al₁₁Ce₃. The Al₁₁Ce₃ increased with the presence of the needle-like and block morphology. As cerium levels increased, the amount of Mg₁₇Al₁₂ decreased. The variations between Mg₁₇Al₁₂ and Al₁₁Ce₃ resulted in a similar normal distribution of the HTS in AZ91 alloy. The findings were further verified through the microstructure evolution and the surface morphology of fracture.     

型砂对铸钢件热裂的影响

本文通过分析型砂热物理性能和高温力学性能与铸钢件热裂的关系,研究了型砂对铸钢件热裂的作用规律,进而比较了几种常用型砂对热裂的影响,得出铸件易热裂规律为:原砂相同时,呋喃树脂砂>水玻璃砂,粘结剂相同时,石英砂>铬铁矿砂>锆砂;原砂、粘结剂都不相同时,呋喃树脂砂>水玻璃砂。     

用支路撕裂法进行大规模模拟电路故障诊断的新算法

本文首先介绍最近出现的一种用支路撕裂法进行的大规模模拟电路的故障诊断算法,讨论了该算法的容差问题。然后将故障预测技术、替代理论和迭加定理运用到支路撕裂法中,得到一个新的故障诊断方程,并给出了一种新的算法。还讨论了算法的并行处理问题。研究结果证明,当连续监测网络时,新算法的在线计算时间和容差问题均较原算法有很大的改进。     

发动机磨合质量及工艺水平分析与研究

讨论和分析了零件在寿命期内动配合副表面特性的变化和磨损量对运行储备的影响,并通过研究表明,在其他条件相同的情况下,磨损率取决于间隙增长率,而间隙增长率取决于动配合的间隙值,并提出了磨合最佳规范及工艺条件.     

加强筋复合非织造材料撕裂破坏机理的研究

对以玻璃纤维网格为加强筋的复合非织造材料进行了撕裂和拉伸断裂试验，分析了网格与复合材料的撕裂机理，探讨了网格和复合材料的撕裂强力与断裂强力的关系。     

集成电路的电路模拟程序

PSCNT1.3是一个在微机上开发成功的集成电路模拟分析程序,具有需要内存少、运行速度快的特点,并有可靠的收敛性.本文较详细地介绍了使PSCNT1.3达到这样效果的主要算法:节点撕裂法、三极管的降阶算法、简化的稀疏矩阵技术,以及改进的牛顿迭代法等.本文还给出了一个应用此程序的计算实例.     

Research on Tearing Property of Reinforced Plastic Film with Bi - axial Warp Knitted Fabric Skeleton

The specification of laid-in and warp yams,thedensity of fabric and the specification of groundyam are of great importance when the bi-axialwarp knitted fabric being knitted.In this paper,the tearing property of the reinforced plastic filmwith bi-axial warp knitted fabric skeleton istested and analyzed.The resuits show thatamong the three factors,the specification of laid-in and warp yam has the greatest influence onthe tearing strength of the reinforced plastic film,while the rest of them has secondary and lesseffect respectively,and there is exponential re-lation between the tearing strength of the rein-forced plastic film and the number of yams in thedirection of force.     

纯棉机织黏合衬的防缩整理

研究了纯棉机织衬布的超低甲醛树脂防缩整理．探讨了树脂用量、催化剂用量、甲醛捕捉剂用量、焙烘时间及温度等因素对整理效果的影响．结果表明超低甲醛树脂整理的最优工艺为：树脂70g／L,催化剂氯化镁7g/L,乙烯脲1g／L。80℃预烘4rain,160℃焙烘120s．整理后衬布的甲醛含量为18．9mg／kg,白度为88．31,撕破强力保留率为88.3％．经向水洗尺寸变化率为-0．40％,纬向水洗尺寸变化率为-0．40％．