Power quality impacts of high-penetration electric vehicle stations and renewable energy-based generators on power distribution systems

High-penetration renewable energy-based generators (REGs) in distribution systems have increased the importance of impact assessment involving these systems. This assessment focuses on power quality (PQ) and compatibility between REGs and existing system components. Electric vehicle (EV) technology has also recently achieved a substantial market share. This technology requires the development of charging stations similar to current petroleum fuelling stations in the near future. Thus, the effect of EV stations (EVSs) on PQ must also be considered. This study presents a PQ analysis on the effects of high-penetration EVS and REG systems, including wind turbines, grid-connected photovoltaics (PVs), and fuel cell (FC) power generation units on a modified 16-bus distribution system under different loading and weather conditions. All data on EVS, wind farm, PV, and FC units as well as weather conditions presented in this paper were collected from different power companies and the Malaysian Meteorological Department. The system is modelled and simulated using the MATLAB/Simulink software to study the effects of these technologies on system performances at various penetration levels. Simulation results indicated that the presence of high-penetration EVSs and REGs can cause severe PQ problems such as frequency and voltage fluctuations, voltage drop, harmonic distortion and power factor reduction.     

以单片机为核心的农用车性能综合测试仪

介绍了以MCS—51单片机为核心的农用车性能综合测试仪的主要性能、硬件结构和软件特点。     

北部引嫩渠首嫩江枯水期来水量与渠道引入量的分析

黑龙江省北部引嫩无坦引水工程，为大庆地区工业及沿途农业灌溉供水运行１６年来，由于引水口上拦沙坡和引水口上游江道河床的变化，枯水期嫩江来水量和供水量发生了矛盾。本文根据实测资料分析分流比减小的原因，并提出若干建议及措施。     

农用运输车发动机与传动系优化匹配的研究

针对目前农用运输车设计、生产中普遍存在的发动机-传动系匹配不够合理的现象,提出了以加速时间和变工况油耗为目标函数、多个约束的优化方法,用以确定当发动机给定后最佳的传动系速比,计算结果令人满意。     

浅析国有施工企业人力资源管理

随着社会和经济的发展,人力资源作为最宝贵的资源,在企业经营管理中的作用越来越重要,作为我国国民经济支柱的国有施工企业,要在市场中生存与发展,就必须重视人力资源管理。然而,国有施工企业人力资源管理现在普遍存在管理理念、用人制度、考评激励、人才机制、员工培训等方面的问题。解决问题的对策在于树立新的人力资源管理观念,建立科学的用人和考评机制,采取激励机制留住人才,加强人才队伍建设,创建学习型企业等途径,提高人力资源管理水平。     

高湿度高山风电场调研及设计特点分析

笔者通过对高湿度高山风力发电场、电力电缆生产厂家的走访、调研,结合规程规范对风电场接线设计、电缆集电线路选型、敷设工艺要求、运行维护注意点等事项进行了充分有效的沟通、交流并进行经验总结。     

航空摄影测量新方法在风电场大比例尺成图中的应用

针对传统航测成图方法的作业效率难以满足工程项目现实性需求的这一现状,文章通过对传统航空摄影测量成图的生产流程分析找寻改进空间,分别借助电子刺点作业模式、立体采集的规范化管理、基于AutoCAD Lisp的符号转码归层程序批量处理,对3个关键环节进行了技术改进,提高了成图效率。     

国有企业面临的深层矛盾及其出路(上)

揭示了当前国有企业改革与发展中面临的２０个深层矛盾，分析了产生矛盾与困境的原因，提出并论证了化解国有企业矛盾、走出困境的基本思路以及“抓重放轻”的改革战略。     

Job demands and pesticide exposure among immigrant Latino farmworkers.

The goal of this study was to understand the potential threat of job stressors to farmworker health. To accomplish this goal we studied pesticide exposure, an issue with immediate and long-term health consequences, and predictions from the Demands-Control model of occupational stress. Longitudinal, self-report data and urine samples were collected at monthly intervals from a cohort of Latino farmworkers (N = 287) during the 2007 agricultural season. The primary hypothesis was that greater exposure to psychological demands, physical exertion, and hazardous work conditions are associated with greater odds of detecting dialkylphosphate (DAP) urinary pesticide metabolites, biomarkers indicating exposure to pesticides. Contrary to this hypothesis, results indicated that none of the elements of the Demands-Control model were independently associated with detection of DAP urinary pesticide metabolites. However, analyses produced several interaction effects, including evidence that high levels of control may buffer the effects of physical job demands on detection of DAP urinary pesticide metabolites. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

浅谈国储库建设工程项目管理

粮库建设项目的管理，虽然属于建筑产品这一工程项目的管理范畴，由于国家储备粮属于重要的战略物资，粮库建筑有其特殊的属性，是以安全存储散粮为目的的专用建筑物。就粮库建筑特殊性，利用经济管理理论，结合新沙港粮库扩建工程实际，介绍国储库建设工程项目管理的一些经验，对今后粮库建设与项目管理具有借鉴意义。