夹芯复合墙板在水平荷载作用下变形的有限元分析

利用有限元程序对夹芯复合墙板在水平荷载作用下的变形进行分析,探讨墙板结构层厚度、水平桁架、纵向桁架、钢筋网作为主要参数变化时对墙板变形的影响。分析得出:影响墙板刚度的主要因素是结构层厚度,其次是水平桁架,其他因素影响较小。该结论为新型复合墙板的研发提供了理论依据。     

武汉华中科大附属中学新校区教学楼设计

华中科大附属中学新校区教学楼积极应对项目所处的特殊的自然环境和人文环境,为学生们创造了一个安全、舒适、轻松的学习环境。从轴线、布局与视觉通廊,台地、院落与景观营造,气候、表皮与建筑形象三个方面阐述了具体的设计策略。     

防腐蚀FRP板材在钢结构建筑上的应用

对耐腐蚀FRP板材所要求的基体树脂、纤维性能进行介绍。总结了在不同行业应用耐腐蚀FRP板材的形式。最后,对采用FRP板材保护的墙面、屋面的常用类型和形式进行了介绍。     

Initial bond formation in thermosonic gold ball bonding on aluminium metallization pads

The morphological features of lift-off footprints on the aluminium metallization pads were investigated to gain an understanding of the effects of bonding parameters on formation of initial bonds during thermosonic gold ball bonding. The obtained results showed that metallurgical bonding initiated at the peripheral areas of the contact area situated along the direction of ultrasonic vibration. Those areas extended inwards with an increase in ultrasonic power. Both the external bonded area and central non-bonded area increased with increasing bonding force. Based on the evolution of footprints, the bonding models were proposed, and the effects of the bonding parameters on the formation of initial bonds were discussed.     

电力系统稳定性计算用励磁系统数学模型的完善

在已有电力系统稳定性计算用励磁系统数学模型(以下简称:励磁模型)的基础上,结合励磁系统的调研和参数测定工作,对励磁模型进行了4个方面的改进与完善;增加了并联PID控制;增加了PID控制的限幅环节;对原有晶闸管整流器模型进行了补充修订;对低励限制环节(UEL)的限制曲线设置进行了修改。     

Power loss minimization considering short‐circuit capacity in distribution system with decentralized distributed generation

In the future, a large number of distributed generators are expected to be connected to the distribution system. However, with the connected capacity of distributed generation (DG) increasing, the problems of short‐circuit capacity (SCC) over the interrupting capacity of the circuit breaker (CB) and power loss increases due to reverse power flow from DG are inevitable. In this paper, a reconfiguration methodology based on an optimal algorithm is applied to the distribution system with DG to minimize power loss, taking into account the SCC. Moreover, in order to further reduce the loss, the daily load variation is also considered and the optimal model decided by calculations. Finally, to illustrate its application, the methodology is applied to a case study of a 33‐bus system with decentralized DG units. The results show that this method is obviously able to reduce power loss and make the network operate in the optimal mode with normal load variation, at the same time decreasing the SCC within the interrupting maximum of the faulty CB. Moreover, the whole voltage profile is also improved. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

反相序引起无功电能表计量差错分析

针对一例无功补偿自动投切装置运行后,功率因数表指示与有功、无功电能表所记电量换算的功率因数不一致的故障,本分析了此问题产生的原因及反相序对无功电能表正确计量的影响。     

电力信号相位差测量方法之探讨

在电力系统中常常需要对两个同频率信号(如工频电压和工频电流)之间的相位关系进行准确的测量。本对“相位—时间”法和“功率比例法”这两种传统的相位差测量方法进行了较为详细的分析,对基于离散付里叶变换的相位测量原理进行了详细的讨论,并给出了实测数据。分析表明,基于离散付里叶变换原理的相位测量方法具有测量精度高、抗干扰能力强、电路设计简单等特点。     

300MW循环流化床锅炉回料阀支撑下陷原因分析与处理

某火力发电厂300 MW循环流化床锅炉回料阀支撑下陷,承载其载荷的次梁连接板发生撕裂.从材料的化学元素、金相组织及力学性能等方面,对故障现象及原因进行了分析、计算,认为安装施工时违反设计要求,在回料阀和立管筒体外壁增设了外保温层,使筒体外壁温度超标而导致筒体线膨胀量超过非金属膨胀节的最大吸收量,且设备受热膨胀产生的热膨胀应力间接传递到了基建时错误安装的次梁上,因应力超过其承载极限导致了次梁连接板发生撕裂.给出了故障处理措施及建议.     

新型投影机高效光源——LED

该文详细介绍了LED作为微型投影机高效投影光源的优势和存在的不足之处,分析了LED作为投影光源需要改进的地方,指出了LED最终会成为未来投影机光源的主流趋势。