电力企业信息系统应用集成技术研究

国内电力企业信息系统存在重复开发、独立运行、分散管理、缺乏规划等问题,难以满足集约化、集中化和精细化管理的要求.文章研究了面向国内电力企业的基于SOA架构的多层次应用集成方案和技术,支持在数据层、服务/消息层和流程层3个层面进行电力行业的应用集成,所采用的集成方案和技术体系都是基于最新的服务应用集成标准和较成熟的技术体系,不仅能降低应用集成的风险,而且还能降低集成工作的成本.     

线程安全队列技术在交流电机调速系统中的应用

介绍了数据保护的概念和原理,根据交流电机调速系统的要求,使用线程安全队列技术对电机的数据进行保护,以期能正确反映电机的运行情况.通过实验,对使用线程安全队列技术的效果进行了验证.     

基于FPGA的异步电动机DSVM直接转矩控制研究

从理论上分析了传统直接转矩控制方案中电压矢量对转矩脉动的影响,针对这一导致电机低速时脉动过大的原因.介绍了基于离散空间矢量调制的直接转矩控制方法.该方法通过将控制周期分为多个时间段.分别细化输出不同电压矢量以达到控制效果优化.并给出了相应的开关表.使用FPGA芯片来实现该方案,实验表明该直接转矩控制方案取得了较好的控制效果.     

正常绒毛和葡萄胎中Mel-CAM标记中间型滋养细胞的增殖情况

目的探讨葡萄胎中Mel-CAM与滋养细胞黏附、浸润之间的关系以及Mel-CAM标记中间型滋养细胞(IT)的增殖情况。方法采用双重免疫组化法,检测Mel-CAM标记IT的Ki-67表达情况。结果葡萄胎中Mel-CAM表达较正常绒毛明显增高,差异有统计学意义(P<0.05);葡萄胎绒毛表面有Mel-CAM标记IT出现,而正常绒毛表面则无;葡萄胎组织中IT的Ki-67指数较正常绒毛明显增高,差异有统计学意义(P<0.05)。结论葡萄胎绒毛表面有Mel-CAM表达,表现出双重分化方向,这可能与葡萄胎的发病机制有关;检测葡萄胎组织中IT的Ki-67指数对于预测葡萄胎的转归有潜在的价值。     

Effects of Heat Intensity and Inflow Wind on the Reactive Pollution Dispersion in Urban Street Canyon

This paper investigates the impacts of heating intensity and inflow wind speed on the characteristics of reactive pollutant dispersion in street canyons using the computational fluid dynamic (CFD) model that includes the transportation of NO, NO₂, and O₃ coupled with NO-NO₂-O₃ photochemistry. The results indicated that the heat intensity and inflow wind speed have a significant influence on the flow field, temperature field and the characteristics of reactive pollutant dispersion in and above the street canyon. With the street canyon bottom heating intensity increasing, NO, NO₂ and O₃ concentrations in street canyon are decreased. The O₃ concentration reductions are even more than the NO and NO₂ concentrations. Improving the inflow wind speed can significantly reduce the NO and NO₂ concentrations within street canyons. But the O₃ concentrations have a slight rise with wind speed increasing. The results would be useful for understanding the interrelation among reactive vehicle emissions, and provide references for urban planners.     

胃食管反流性胸痛的临床特点及食管测压分析

对２４例胃食管反流性胸痛患者的食管测压分析，显示可出现食管下扩约肌静止压及食管上扩约肌静止压异常升高、体部高幅蠕动或蠕动紊乱等不同类型的食管运动障碍。表明胃食管反流性胸痛的发生与这种食管的运动障碍有关。对其发生机理及临床特点进行了讨论。     

三次映射的全局分叉与浑沌

本文研究了一维三次映射ｘ→Ｆλ（ｘ）＝ｘ＾３－λｘ的全局分叉与浑沌。证明了当λ＞１＋３√２／２时，存在一个Ｃａｎｔｏｒ集。对任何的ｎ≥３，Ｆ＾ｎλ至少产生两次鞍结分叉。每次鞍结分叉后，又有两对称的周期培化序列产生。各位化序列发生的次序十分复杂，但均有相同的Ｆｅｉｇｅｎｂａｕｍ数。同宿和异宿分叉导致了多个不同的浑沌集的形成。     

马氏体合金铸铁堆焊焊条研究

通过硬度试验,显微硬度,光学显微镜以及Ｘ光衍射相分析对马氏体合金寿铁堆焊金属进行研究,确定焊条药皮配方,使堆焊金属硬度ＨＲＣ大于６６,高于目前同类产品的硬度值。     

An Approach to Stability Analysis of Sliding Motion in a Clearance Joint of a Four-Bar Mechanism

The sliding motion refers to the case when the pin of a revolute joint is in contact with the bush, following all or a segment of the circular trajectory inside the bearing. The equation of the sliding motion is obtained based on Lagrangian approach. By use of the classical continuation method, the stationary points can be calculated, and their local stability is determined with the theory of stability. This paper focuses its analysis on the joint connecting the rocker of a four-bar mechanism to the ground. The results show that there are some relations between the local stability of sliding motion and contact loss     

柴油机机体瞬态动力学的有限元分析

机体是柴油机的骨架,工作过程中承受多种载荷的作用.利用PROE软件建立了柴油机机体的三维实体模型,通过网格划分软件MSC.GSMESHER对模型进行了网格划分,采用有限元软件MSC.NASTRAN对考虑气体压力、轴承力、活塞敲击等各种主要激励的机体进行了瞬态响应分析.通过与试验值的比较验证了计算的准确性.