Application of data fusion method to fault diagnosis of nuclear power plant

The work condition of nuclear power plant (NPP) is very bad, which makes it has faults easily. In order to diagnose the faults real time, the fusion diagnosis system is built. The data fusion fault diagnosis system adopts data fusion method and divides the fault diagnosis into three levels, which are data fusion level, feature level and decision level. The feature level uses three parallel neural networks whose structures are the same. The purpose of using neural networks is mainly to get basic probability assignment (BPA) of D-S evidence theory, and the neural networks in feature level are used for local diagnosis, D-S evidence theory is adopted to integrate the local diagnosis results in decision level. The reactor coolant system is the study object and we choose 2# steam generator Utubes break of the reactor coolant system as a diagnostic example, The experiments prove that the fusion diagnosis system can satisfy the fault diagnosis requirement of complicated system, and verify that the fusion fault diagnosis system can realize the fault diagnosis of NPP on line timely.     

T型钢主梁与横隔板的构造设计

在大偏轨主梁上使用T型钢,一般是起重量较大、工作级别较高的起重机.目前这类起重机主梁与横隔板之间的焊接方式有好几种,本文通过分析计算,说明具体哪一种焊接方式比较合理,既能满足强度要求,又能满足稳定性的要求,而且制造工艺简便.     

集水坑与潜水排污泵在地下车库的设置

地下车库内部地面标高低于室外标高,排水设计中须设置地漏、集水坑和排污泵等设施,采用压力排水.设备的选型及个数应充分利用结构埋深,优化设置,安排有据,经济合理.     

考虑决策过程与潜在异质性的居民通勤选择行为研究

传统研究对居民通勤决策过程的动态性及微观心理偏好关注不足，为此利用潜在类别模型表征居民通勤决策的潜在异质性，从动态决策角度出发，构建可以体现偏好动态演进过程的决策场理论模型。该模型对不同潜在类别设置差异化的属性注意力权重，表征不同子市场用户动态偏好的差异性和相同子市场用户偏好似而不同的特征，同时实现用户分类和动态决策过程分析，改进传统决策场理论对个体偏好异质性表征不足的缺陷。对成都市轨道交通车站附近居民进行实证研究，结果表明，通勤居民可以细分为“商务需求型”“追求效率型”“经济环保型”“保守型”这4类，各类别间的备选方案初始偏好、属性关注程度均呈现显著差异。通过Matlab仿真实现对个体决策结果、微观偏好进化过程及非理性效应的预测和分析，验证了本文方法的有效性。     

高重频激光产生窄带声的声源特性与性能分析

为分析高重频激光产生窄带声的声压谱级和转化效能,在高重频激光产生窄带声(重频法)的理论基础上,对声压功率谱进行了仿真。结合激光器的技术指标,以声压在主频处的功率谱为参考将重频法和连续波法、长脉冲法的性能进行了比较,实验研究了激光脉冲数与声压谱级的关系。理论和实验分析表明,增加激光脉冲数可以压缩声压带宽并提高声压谱级。当脉冲数为100时,重频法在主频处的声压功率谱比连续波法高14d B,比长脉冲法高10d B。在800m J、重频25k Hz的激光脉冲作用下,20个脉冲产生的声压谱级为127.1d B,200个脉冲产生的声压谱级为135.4d B。     

Sealed v/s open bids for certificates of entitlement under the vehicle quota system in Singapore

The Vehicle Quota System manages vehicle ownership in Singapore by making the procurement of a Certificate of Entitlement (COE) a prerequisite for the registration of a new vehicle. The procurement is done during uniform price auctions of quotas of COEs currently held on a twice-a-month schedule. The auction format which started out as sealed bids in May 1990 changed to open bids in July 2001. This paper uses a regression model framework to investigate if this shift in auction format has resulted in lower COE premium volatility and a better reflection of demand and supply forces. The empirical results are pertinent to transport policy analysis. A suggestion in the form of incentives for early bids is also made to improve the efficiency of the open bids auction.     

一种用于SWATH湿甲板动响应分析的砰击载荷实用计算方法

利用连接桥模型试验,通过对几种砰击载荷计算方法的比较,提出用抛物线型函数对砰击压力进行二元非线性回归,与试验值吻合较好,得到了一种用于SWATH湿甲板动响应分析的砰击载荷时历载荷形式.给出一条船的算例,分析了湿甲板砰击的特点,得到航速、有义波高、遭遇频率、湿甲板高度都是影响砰击发生及其量值的因素的结论,指出在分析湿甲板砰击强度时必须采用动响应分析法.     

无刷直流推进电动机稳态性能的仿真

建立无刷直流推进电动机的稳态仿真数学模型,利用特征向量法以及对称性边界条件进行求解,得到定子三相电流的稳态解,并与动态仿真的结果进行对比,验证了该方法的正确性。     

城市轨道交通视频监控系统资源共享方案研究

在分析城市轨道交通专用、警用视频监控系统差异化需求的基础上,介绍了专用、警用视频监控系统资源部分共享和完全共享两套建设方案及其特点。对两套方案进行比选,在满足城市轨道交通运营部门和公安部门使用需求的前提下推荐选用完全共享方案。探讨了完全共享视频监控系统建设时需考虑的诸多问题。     

港口石油化工码头及其库区灾害事故应急系统研究

本文通过对石油化工码头及其库区危险因素的分析,提出了石油化工码头及其库区灾害事故应急预案编制的要求和内容,以及石油化工码头及其库区灾害事故应急技术支持系统。