基于PMM8731和SI-7300的步进电机驱动电路

PMM8731是日本三洋电机公司生产的步进电机脉冲分配器。而SI-7300则是日本三青公司生产的高性能步进电机集成功率放大器。它们和单片机一起可构成一种高效电机控制驱动电路。文中介绍了PMM8713与SI-7300的功能 ,给出了由它们组成的功率驱动电路及其在步进电机上的应用方法     

Investigation of the impact of changes in demand forecasting method on the financial performance of an electricity supply undertaking

Peak demand forecasts obtained from six different univariate forecasting methods, under a range of conditions, were used to drive a capacity acquisition model of a large electrical supply system; and the resulting physical and financial performance of the model was observed for each set of forecasts. The results obtained are discussed in the context of their implications for the choice of load forecasting method used in capacity acquisition planning by a power supply undertaking.     

探讨电石法PVC烟气治理方法

分析了电石法PVC生产链中电石炉烟气及电厂烟气二氧化硫的排放情况,指出利用电石炉烟气中的CO合成氨、再将合成氨用于燃煤电厂烟气的"氨法"脱硫是具有较大应用潜力的循环经济产业链。     

从《左传》录诗看孔子是否删诗

孔子是否删诗，这是一个历史遗留问题。司马迁首言在前，孔颖达怀疑在后。宋之后，争议遂起，延至近代。今人夏传才先生断日：孔子是否删诗，“在没有发掘出新史料的情况下，哪怕再争论八百年，也是搞不清楚的”。以此止息纷争。话虽不错，但问题并没有解决。我认为，在没有发掘出新史料的情况下，可以从《左传》入手，来考察孔子是否删诗。     

Heat Transfer Analysis for Gas-to-Liquids Transportation Through Trans Alaska Pipeline

Gas-to-liquids (GTL) technology involves the conversion of natural gas to liquid hydrocarbons. In this article, theoretical studies have been presented to determine the feasibility of transporting GTL products through the Trans-Alaska Pipeline System (TAPS). To successfully transport GTL through TAPS, heat loss along the route must be carefully determined. This study presents heat transfer and fluid dynamic calculations to evaluate this feasibility. Because of heat loss, the fluid temperature decreases in the direction of flow and this affects the fluid properties, which in turn influence convection coefficient and pumping power requirements. The temperature and heat loss distribution along the pipeline at different locations have been calculated. Fairly good agreement with measured oil temperatures is observed. The powers required to pump crude oil and GTL individually, against various losses have been calculated. Two GTL transportation modes have been considered; one as a pure stream of GTL and the second as a commingled mixture with crude oil. These results show that the pumping power and heat loss for GTL are less than that of the crude oil for the same volumetric flow rate. Therefore, GTL can be transported through TAPS using existing equipment at pump stations.     

主跨348m+348m三塔单索面PC梁斜拉桥

宜昌市夷陵长江大桥采用三塔斜拉桥，总体布置为(128．08 348 348 120．35)m。介绍了该桥的合理性及结构特点。     

电力负荷削峰减载系统在珠钢电炉的应用

借助现场采集装置,在计算机上获取每一分钟的冶炼工艺电能需求量,显示当前15分钟时段已发生的电耗量,调整用户设定,实现需量自动刷新、报警和专家分析推荐后续用量;实现平稳用电并减少对电网冲击,同时降低电能最大需用量以减少成本。     

操纵员心理评价方法研究

文章对核电厂操纵员心理定性化评价以及定量化评价方法进行分析和探讨。对轮廓图匹配法和模糊综合评价法的适用范围、应用效果进行了比较分析。该研究的结果可为操纵员评价提供有益参考。     

基于多随机变量风险约束的水电站长期优化调度

针对市场环境下水电站如何综合考虑电价和来水等不确定性因素下的优化调度是当前研究的热点和难点,建立了考虑电价和来水等不确定性因素的风险约束水电站长期优化调度模型。根据此模型发电商可方便地在预期的目标收益和风险之间进行权衡,达到以较小的风险获得较大的收益的目的。以二滩电厂实算为例,表明了该模型的有效性。     

应用SPC技术对机械零件加工过程的管理和控制

介绍了SPC(统计过程控制)技术原理，以某传动轴外径φ45 0.50^0.90 mm为控制对象，提出应用SPC技术，对机械零件加工过程进行管理和控制，从而达到过程失控预警、过程不断改进、过程能力不断提高的目的，继而保证产品质量的稳定和不断提高。