电容电流对供电系统的影响及消除措施

结合单位供电系统现状,对在小电流接地系统中发生接地故障时电弧产生的原理、对供电系统安全的影响及通过消弧线圈进行消除的措施进行了阐述。     

500kV户外型变电站作业场所电磁环境实测分析

为了研究500k V户外型变电站作业场所的电磁环境,利用EFA-300电磁场强分析仪对9座不同类型的500 k V变电站作业场所的电磁场强度进行实测。共设置412个测点,覆盖3种典型变电站的室内作业场所和室外作业场所。测试结果显示:室内作业场所电磁场强度均远远低于国家关于公众暴露限值的标准(E≤4 k V/m,B≤100μT);不同类型500k V户外型变电站室外作业场所的电磁场强度平均值由高到低为:HGIS型变电站>AIS型变电站>GIS型变电站,表明GIS型配电方式更有利于减轻电磁污染。室外作业场所共有19.8%的测点电场强度超过我国行业标准(E≤5 k V/m),0.7%的测点磁感应强度超过我国行业标准(B≤500μT),其高电磁场强度区域集中在高压侧设备区以及电抗器密集区,最高电场强度达到14.860 k V/m,最高磁感应强度达到856μT,应重视此类区域工作人员的电磁场防护工作。     

市政水处理行业电气节能设计实例研究

在北京市第十水厂工程电气设计实践的基础上,论述了市政水处理行业电气节能设计的主要步骤和关键问题。完备的供配电系统可以减少其在运行中的能源损耗,实现其经济运转;先进、智能的电动机启动及运行方式可减小电网电压波动,降低损耗,提高电机在轻载时的效率及功率因数达到节能的目的;科学地设计了照明功率密度,分配不同区域的照度,选择节能光源,并充分利用太阳能,在满足生产构筑物对照明的功能性要求及各构筑物内部的照度水平、视觉环境和照明效果的前提下,最大限度地降低照明系统的电能消耗,使电气节能的概念落实到系统的最末端。     

微通道中电场作用下的液滴生成过程研究

利用数值模拟方法对电场作用下的十字型微通道中的液滴生成过程开展了研究,通过CLSVOF耦合模型和电磁流体模型考察了液滴生成不同阶段的形态演变及速度、压强分布规律,分析了液滴断裂的生长、挤压和断裂机制。研究结果有助于加深对微通道中多相流动、特别是电场的影响效果的理解,为微反应器设计与控制提供理论指导与数据支撑。     

Road traffic crashes among farm vehicle drivers in southern China: A cross-sectional survey

Objective: The objective of this study was to identify the prevalence and potential risk factors of farm vehicle–related road traffic crashes among farm vehicle drivers in southern China.

Methods: A cross-sectional study was used to interview 1,422 farm vehicle drivers in southern China. Farm vehicle–related road traffic crashes that occurred from December 2013 to November 2014 were investigated. Data on farm vehicle–related road traffic crashes and related factors were collected by face-to-face interviews.

Results: The prevalence of farm vehicle–related road traffic crashes among the investigated drivers was 7.2%. Farm vehicle–related road traffic crashes were significantly associated with self-reported vision problem (adjusted odds ratio [AOR] = 6.48, 95% confidence interval [CI], 3.86–10.87), self-reported sleep disorders (AOR = 10.03, 95% CI, 6.28–15.99), self-reported stress (AOR = 20.47, 95% CI, 9.96–42.08), reported history of crashes (AOR = 5.40, 95% CI, 3.47–8.42), reported history of drunk driving (AOR = 5.07, 95% CI, 2.97–8.65), and reported history of fatigued driving (AOR = 5.72, 95% CI, 3.73–8.78). The number of road traffic crashes was highest in the daytime and during harvest season. In over 96% of farm vehicle–related road traffic crashes, drivers were believed to be responsible for the crash. Major crash-causing factors included improper driving, careless driving, violating of traffic signals or signs, and being in the wrong lane.

Conclusion: Findings of this study suggest that farm vehicle–related road traffic crashes have become a burgeoning public health problem in China. Programs need to be developed to prevent farm vehicle–related road traffic crashes in this emerging country.     

Some Aspects of Vehicle Active Safety

Three selected aspects of vehicle active safety are presented in this article: (a) modeling the driver and the driver–vehicle environment system, (b) the dynamic aspects of vehicle rollover, and (c) an analysis of the process of passing. Sample solutions and results show the need for further research in the field of vehicle safety in order to lower the probability of drivers, passengers, and other road users being involved in road accidents.     

燃料电池汽车氢源基础设施的生命周期评价

为了推动生命周期评价的应用和发展并为我国制定燃料电池汽车氢源基础设施的近期规划提供参考,根据现有的生产、储存和输运氢的技术,针对燃料电池汽车氢源基础设施,设计了10种可行方案,运用生命周期评价方法对这些方案的环境影响进行了全面评价,得到了每种方案的分类环境效应标准化指标,并对若干参数进行了敏感性分析.结果表明,环境性最好的燃料电池汽车氢源基础设施方案是:天然气集中制氢厂制氢,然后用管道将氢气输运到加注站,加注给以氢气为燃料的燃料电池汽车.     

均匀电场下多环芳烃在土壤中的迁移

当循环电解液流速为800 mL/h,电解液为无菌水时,电渗流流量、菲和芘在土壤中迁移量在电压梯度为1 V/cm作用下比电压梯度为0.5 V/cm时要多;电动注入表面活性剂Tween80和HPCD均可以提高菲和芘在土壤中的迁移,注入Tween80和HPCD浓度分别为500和1 000 mg/L时,相应地Phe提高5.8倍和11.7倍、芘提高2倍和3.4倍;而BaP在水中的溶解度太小,电场作用和电动注入表面活性剂对BaP在土壤中的迁移量影响很小。为建立电动修复有机污染物污染提供了技术基础。     

电拌热在污水处理系统中的应用

由于北方冬季气温较低，因冬季防冻及工艺需加装拌热装置，如果在污水处理系统中安装电拌热装置。不仅能有效的解决系统设备及管道的防冻问题，而且电拌热的运行成本较蒸汽拌热低、使用年限长，维护简单，有很好的使用及推广价值。     

荷电水雾除尘器的机理研究

荷电水雾除尘技术是一种新型的除尘技术。本文介绍了荷电水雾除尘器的工作原理，着重分析了其对静电除尘器及湿式除尘器缺点的克服，以及荷电水雾除尘器的性能特点与存在的不足之处。