复合次级管型直线电机性能计算

简述了复合次级管型直线电机的结构特点和由其结构所决定的优越性能,给出了此种电机三层模型与此模型的等效电路,推导出确定等效电路中电气参数的公式,进而给出按等效电路计算电机性能的公式,为求取和分析复合次级管型直线电机的特性提供了有效方法．     

DOS操作系统下内存资源的利用

从计算机用户的角度出发，说明如何在ＤＯＳ操作系统下更好地使用更多的内存资源，并给出了有关扩充内存的高级编程方法。     

间位芳纶纸板的制备及性能研究

采用间位芳纶短切纤维和沉析纤维为原材料制备了芳纶纸板,分析了纤维配比、温度及压强对纸板电气强度及拉伸性能的影响,并对纸板金属离子含量、水浸液电导率和p H值、耐油污性能等进行了研究。结果表明:间位芳纶纸板最佳的纤维配比为短切纤维∶沉析纤维=5∶5,最佳工艺是热压温度280℃、热压压强8 MPa。间位芳纶纸板的综合性能达到国外同类产品水平,具有良好的应用前景。     

核电机组低压安注试验限流孔板调整计算

当反应堆发生事故时需要安全注入系统向反应堆注入冷却水以减轻或控制事故发展。核电站日常运维中需要执行低压安注试验以验证不同工况下安全注入系统向反应堆注入冷却水的流量是否满足设计要求。当试验结果不满足设计要求时需要对低压安注系统相应管路上的限流孔板孔径进行调整。通过对限流孔板计算分析和复杂管路的管路特性的分析结合伯努利方程给出了低压安注试验中涉及的限流孔板孔径调整计算方案。通过某核电站4号机孔板调整实例验证,理论计算的孔板孔径与实际偏差不足1%。实践表明,提出的限流孔板孔径调整计算方案能够满足工程需求。     

带感应耦合器的永磁同步风力发电系统建模与分析

对一种新型风力发电系统——带感应耦合器的永磁同步风力发电系统进行了研究.建立了自然风、风力涡轮机、感应耦合器及永磁同步发电机的数学模型和仿真模型.建立基于传递函数的系统整体动态仿真模型,并将其作为分析研究系统动态特性的工具.对阵风和涡轮机转矩产生7.5Hz波动条件下,有和无感应耦合器两种情况下永磁同步风力发电机的特性进行对比分析.讨论了感应耦合器的等效电阻对系统特性的影响.研究结果表明,引入感应耦合器有效削弱了干扰对系统的影响,降低了电压闪变程度,改善了风速变化或涡轮转矩波动时系统运行不稳定的情况.另外,耦合器等效电阻的减小可减小其运行的转差率,提高系统效率,但稳定性有所下降.     

高速冲槽机分度系统不准造成的原因分析

简述了造成高速冲槽机分度系统不准的原因及分析。     

核电厂重要厂用水系统换热器热力性能评价方法分析

为解决北方某核电厂重要厂用水系统冬季工况下换热器热力性能评价问题,结合换热器传热设计的基本理论及换热器热力评价相关文献,对比分析目前各核电厂对该换热器热力性能评价方法原理及适用范围,总结现有评价方法在冬季变工况运行下换热器热力性能评价中存在的不足,针对这些不足提出了冬季变工况下换热器热力性能评价适用性改进方案。     

Microfluidic technology for multiphase emulsions morphology adjustment and functional materials preparation☆

Multiphase emulsions could be used as templates in considerable fields such as coating, optical materials, stan-dard particles and biomedicine. Among various emulsion forming methods, microfluidic technology, with good monodispersity, high controllability and operation simplicity, has been widely used in the preparation of multi-phase emulsions with different systems. This review would focus on the basic principles of forming multiphase emulsions, the recent progress in control ing multiphase flow in microfluidics, and preparation of functional ma-terials with microfluidics mainly by the authors' research group. We believe that the review wil contribute to the readers in this prospective area very wel .     

Effects of pre-oxidant (KMnO4) on structure and performance of PVDF and PES membranes

The structure and performance of membrane materials are very important to the efficient and stable operation in membrane drinking water purification technology. Potassium permanganate (KMnO₄), which can change the characteristics of organic matters and control membrane surface fouling, has been widely used as pre-oxidant in the front of membrane drinking water process. This study investigates the evolution of membrane surface structure and performance when polyvinylidene fluoride (PVDF) and polyethersulfone (PES) were exposed to 10, 100 and 1000 mg·L^-1 KMnO₄ solution for 6 and 12 d, respectively. The aged membrane physicochemical characteristics such as membrane surface morphology, chemical composition, hydrophilicity, porosity and zeta potential were evaluated by modern analytical and testing instruments. The anti-fouling property of membrane surface was also investigated by the filtration-backwash experiment. The results indicated that the different concentrations and exposure time of KMnO₄ led to a different variation on PVDF and PES membrane surface structure and performance, which could further affect the membrane separation performance and the membrane fouling behaviors. The membrane surface pore size and porosity increased due to the dislodgment and degradation of membrane additive (PVP), which improved membrane permeability and enhanced the adsorption and deposition of pollutants in the membrane pores. With the increase of exposure time, the membrane surface pore size and porosity reduced for the reactions of chain scission and crosslinking on membrane materials, and the backwashing efficiency declined, leading to a more serious irreversible fouling. Compared with PVDF membranes, the formation of sulfonic group for PES membranes increased the negative charge on membrane surface due to the oxidation of KMnO₄. The present study provides some new insights for the regulation of the pre-oxidant dose and the selection of the membrane materials in KMnO₄ pre-oxidation combined with membrane filtration system.