分布式智能ERP体系结构的研究

文章分析了传统ERP系统存在的问题,针对系统智能性、可重构性差等缺点,基于"软件人"、多库协同等技术提出了"分布式智能ERP系统"的体系结构模型,为系统的设计和应用提供了基础.     

OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

1. INTRODUCTION Vehicular emissions have become one of thmain sources of urban atmospheric pollution in Chinwith the development of the urban construction andthe increase in the number of vehicles. There are lots of factors influencing the transport and dispersion of vehicular exhausted pollutants and further influencing the local air quality, among which the gas dynamical effect due to the mechanical turbulence from huge buildings and street canyons is especially remarkable. Previous stu…     

基于ARM处理器的数字PID伺服电机调速系统

介绍了基于ARM处理器的数字PID控制方式实现对直流伺服电机的调速。调速系统根据实际情况,采用了优化PID的算法并移植了μC/OS-Ⅱ实时操作系统,使得电机的调速性能在快速性、平稳性方面都得到了很大的提高。整个伺服控制系统结构简单、控制方便、实时性高,已经取得了良好的实验效果,可以满足电机高速高精度的运行要求。     

载银/铜NaA分子筛的制备及抗菌性能研究

探讨了液相离子交换法制备载银/铜NaA分子筛抗菌剂的实验条件,并对载银/铜NaA分子筛样品中载银、铜的含量,抗变色性能及对大肠杆菌、金黄葡萄球菌的抗菌性进行检测。结果表明,与单独载银的NaA分子筛相比,载银/铜NaA分子筛中银和铜含量分别达到5.5%和1.6%,色差更小,抗菌性显著提高。     

Study on electrothermally actuated cantilever array for nanolithography

Nanolithography is a patterning technique for the fabrication of nano-scale structures.A promising method of nanolithography known as scanning probe lithography has particularly extensive applications for its high resolution,high reliability,and simple operation.In this paper,a novel electrothermally actuated cantilever with integrated heater,thermal conductor and actuator for scanning probe lithography is proposed.Cantilevers are designed in an 8×4 array.Analytical models are presented to simulate the temp...     

Effect of heat treatment on mechanical properties of heavily cold-rolled Fe-6.5wt%Si alloy sheet

Fe-6.5wt%Si alloy has excellent soft magnetic properties,but it is hard to be cold-rolled due to appearance of ordered phases in this alloy.In this paper we report that ultra thin Fe-6.5wt%Si sheet of 0.05 mm thick was obtained by heavily cold rolling.By means of optical microscope,micro-hardness indenter,instron,SEM and X-ray diffraction,the effect of heat treatment on mechanical properties of this alloy sheet was investigated.The heavily cold-rolled sheet exhibits some extent of ductility.The ultimate ten...     

Room temperature ferromagnetism of Ni, (Ni, Li), (Ni, N)-doped ZnO thin films

Ni-doped ZnO thin films (Ni concentration up to 10 mol%) were generated on Si (100) substrates by a sol-gel technique. The films showed wurtzite structure and no other phase was found. The chemical state of Ni was found to be bivalent by X-ray photoelectron spectroscopy. The results of magnetic measurements at room temperature indicated that the films were ferromagnetic, and magnetic moment decreased with rise of Ni concentration. The magnetization of Ni (10 mol%)-doped ZnO film annealed in nitrogen was low...     

新型钢筋混凝土叠合结构体系研究

随着我国建筑事业的飞速发展,建筑能耗不断增加,已成为不能忽视的问题,大力发展节能建筑势在必行。新型钢筋混凝土叠合结构体系由预制构件在现场组装并浇筑部分混凝土叠合而成,具有很好的整体性、抗震性以及卓越的节能环保性能,在很大程度上降低了建筑能耗。探讨了此体系的(主要构件、典型节点、构造措施)设计方法、工厂制作工艺、现场装配施工过程及关键技术问题。为我国建筑事业逐步迈入节能环保、安全耐久的可持续性发展奠定了基础。     

考虑磁场饱和效应的凸极同步电动机建模

针对常规线性磁场模型难以准确描述凸极同步电动机的稳态和动态特性,磁场饱和效应严重影响高性能电动机驱动系统的控制精确度,对凸极同步电动机磁场饱和模型进行了研究.阐述了电动机d-q轴交叉饱和的机理,采用稳态饱和电感,动态饱和电感以及交叉饱和电感来表述磁场非线性的特征,建立了凸极同步电动机非线性磁场饱和模型,同时给出了其状态空间方程.采用矢量控制策略对凸极同步电动机的磁场饱和模型进行仿真分析,结果表明电动机的励磁电流能根据磁场饱和程度做出准确的响应建立电动机的磁场,d-q轴电流和负载功角的变化规律完全符合磁场饱和运行工况,验证了模型的有效性.     

高速电磁阀驱动控制策略的研究

介绍了单体泵高速电磁阀驱动电路的原理,电路采用了高压侧高压启动和低压维持的控制策略,并且在低压维持阶段加入了PWM控制,实现了电磁阀的快开快闭,同时也节省了能耗。该电路的优点在于电磁阀的开启、维持电流以及PWM信号频率及占空比均可调,能够很好地控制电磁阀的开闭,并且能大大降低功耗。