8K机车辅助电源能流循环试验台变流系统

能流循环试验台是针对8K机车辅助电源系统测试而设计的节能试验装置,用于辅助电源变流系统的日常测试和维护.辅助电源变流系统由晶闸管整流器和被测IGBT逆变器组成,负载采用PWM整流器控制输出电流.变流系统由以DSP为核心的数字控制系统控制.试验证明,该试验台能在满足额定功率测试的条件下,大大节约电能,减少噪声污染.     

Effects of RE on the Microstructure of Mg-8Zn-4Al Magnesium Alloys

IntroductionMagnesium alloys are called green-engineeringmaterial with great development potential becauseof its low density, high specific strength and stiff-ness, superior damping capacity, good electromag-netic shielding characteristics and good machinabil-ity[1]. However, the number of commercially avail-able magnesium alloys is still limited especially forapplication at elevated temperatures. The applica-tions of most common magnesium alloys such asAZ91 and AM60 with outstanding mechani…     

病因模拟法建立小儿厌食症动物模型

采用病因模拟法建立小儿厌食症动物模型。方法　用鱼松、奶粉、黄豆粉、白糖、鸡蛋等市售食品按比例配制特制饲料喂养幼龄大鼠建立动物模型 ,观察对大鼠摄食量、体重及下丘脑和血浆八肽胆囊收缩素 ( CCK- 8)浓度的影响 ,同时对特制饲料与常规鼠饲料的主要营养成分进行对比。结果　模型大鼠日摄食量明显低于对照组 ,体重增长缓慢 ,下丘脑和血浆八肽胆囊收缩素水平显著升高。特制饲料多种矿物质及多种维生素含量低下。结论　该模型符合小儿厌食症的自然病因和主要临床表现 ,状态稳定 ,基本成功     

船舶CAD／CAE系统面向对象数据库的开发

针对关系型数据库在处理船舶设计复杂工程数据方面的不足,提出了采用面向对象数据库构建船舶设计数据管理系统基础平台的优越性,系统地介绍了船舶CAD/CAE系统面向对象数据库的设计及在Oracle 10g数据库上的实现方法,基于对象,关系数据库Oracle 10g采用JSP技术建立了B/S结构的船舶CAD/CAE数据管理系统为船舶CAD/CAE数据在Web上交互、共享和存储提供了一种有效途径.     

小儿过敏性紫癜血清炎前因子的检测及其意义

目的　探讨炎前因子在过敏性紫癜免疫病理损伤中的作用。方法　采用双抗体夹心ELISA法和硝酸还原酶化学比色法分别检测过敏性紫癜 (SHP)患儿血清肿瘤坏死因子α(TNFα)、白细胞介素 6(IL 6)、白细胞介素 8(IL 8)和一氧化氮 (NO)的浓度。结果　SHP急性期血清 4种炎前因子水平明显高于正常对照组 (P <0 .0 5 )。肾型中活动性肾脏病和 (或 )肾功能不全组较其他组血清IL 6明显升高 (P <0 .0 1 )。恢复期TNF α、IL 8仍高于正常对照组 (P <0 .0 5 )。急性期 4种炎前因子间呈正相关关系。结论　血清 4种炎前因子水平与SHP的发生、发展有关。     

Oracle中实现定时任务的分析与应用

对Oracle Job Queue进行介绍与分析,提供在Oracle中实现定时任务的步骤和方法,并通过一个应用实例进一步加以阐述,对Oracle定时任务异常时的现象及处理办法进行总结.     

A study of the response of chlorophyll-a biomass to a winter upwelling event off Western Iberia using SeaWiFS and in situ data

Observations of a winter upwelling event off Western Iberia shelf/slope in the area of influence of the Western Iberia Buoyant Plume (WIBP) were conducted in February 2000. Spatial patterns and time evolution of the chlorophyll-a (chl-a) biomass are analysed, based on in situ and satellite data. SeaWiFS-derived chl-a concentration L2 products were used to track the chlorophyll front and estimate its westward migration velocity (maximum up to 29 km day⁻¹), as well as to characterize the frontal system and its evolution. A method associating the type of spectral signature of a pixel to the fraction of chlorophyll probed by SeaWiFS enabled the estimation of the chl-a biomass within error intervals. High chlorophyll concentrations (for wintertime) were observed over the shelf and slope, up to large distances to the coast. Due to the WIBP, a shallow Ekman layer developed, being nearly coincident with the stratified upper meters. The transport comprised westward advection and stretching of the plume, with little entrainment with the offshore deep mixed layer waters. The relative enlargement of the total area of the Inside-Front Zone (IFZ) during the upwelling event was roughly accompanied by the maintenance of the average biomass per unit of area, considering the water column up to depths of interest. This suggests that there was a net increase of chl-a biomass inside the water column associated with the IFZ, roughly proportional to the increase in the IFZ area. Retention of phytoplankton in the shallow stratified nutrient-rich waters of the WIBP was a key factor for this increase in chl-a biomass.     

SS8型电力机车整车动态检测系统

介绍了SS8型电力机车动态检测系统设备的总体布置、系统的组成、结构特点、基本性能及主要技术参数。该检测系统能够满足机车中修后不上线即可进行牵引负荷试验的要求，并能够查找机车故障，调整标定参数。试验数据可直接输入、存储在微机系统，是一种非常实用的、现场型的检测系统。     

SS8机车一系垂向减振器仿真系统的研究

对我国提速机车广泛应用的SS8型一系列减振器进行了深入的研究，建立了数学模型，并开发出该减振器的计算机仿真软件，运用仿真软件进行算例仿真，通过比较可以看出，计算结果与实验结果是一致的。     

构建网络中心战体系结构

美军正围绕网络中心战，将冷战时期作战结构向21世纪新的作战样式转型。网络中心战是在大量分析信息网络技术的性能改善和效能提高的基础上而提出的一个新概念，这个概念在反恐战争中得到越来越多的体现，二战以来，以从未有过的方式改变着战争的作战原则、战术和兵力结构。分析在构建有效的网络中心战基础结构时面临的挑战，研究Oracle公司针对这些挑战所做出的响应。