关于有源高功率因数电子镇流器的讨论

讨论高性能电子镇流器系统必需具备的电路结构、功率因子校正电路的基本原理,介绍美国微线形公司(MicroLinearCorporation)生产的高性能电子镇流器控制器ML4831的基本工作原理、特点。     

Resource utilisation and power relations of community sport clubs in the aftermath of natural disasters

Community sport clubs (CSCs) provide a number of benefits to local communities, while confronting challenges with finances and staffing. In Queensland, Australia, these challenges have been compounded by recent natural disasters including widespread flooding that have significantly impacted operations of CSCs. The current research explores the provision of resources to CSCs in the aftermath of flooding events in 2010 and 2011, as well as the influence on power relations between CSCs and resource providers. To address this research purpose, qualitative data were collected across nine site visits (focus groups, interviews) to affected CSCs. The data revealed three resource providers: volunteers and members, partner organisations and government. In addition, the results indicate that relations between CSCs and members and volunteers, partner organisations and government were impacted in different ways. Examples of resource providers wielding power over CSCs due to the provision of resources emerged, along with some evidence of mutual power and dependence and CSCs exerting power over resource providers. The results provide implications for CSC managers to be more proactive in relation to resourcing through developing strategies for network building and improved communication within networks.     

无线图像传输系统在黄河防汛指挥中的研究与应用

针对山东黄河防汛工作整体要求和信息化建设现状,利用无线图像传输加快防汛信息现代化建设,在更广阔的地域范围内提供“最后一公里”宽带连接,结合山东黄河应急平台建设方案要求,其建设将成为黄河防汛应急管理的一项重要基础性工作。全面推进水利信息化和国家防汛抗旱指挥系统工程建设,是水利可持续发展的基础和前提,充分运用现代计算机网络技术、现代通信技术,建立科学的、高效的防汛指挥系统,减轻洪涝灾害损失,确保防洪安全。     

基于EDS算法识别电压暂降的研究

电压暂降是电力系统中常见的一种电气故障。本文针对电网中经常发生的电压暂降的情况,通过对实际中的电力系统中的电压暂降故障与正常运行时候的电压进行采集,并应用欧氏距离平方(EDS)算法对两种情况下的数据进行计算,统计出不同情况下即所得到的欧氏距离平方值的范围,同时比较一下大小。经过对大量的电压暂降情况进行计算比较,结果表明,发生电压暂降情况下,欧氏距离平方值要明显大于正常情况下的值,而且该算法步骤少,计算速度快,能够达到快速、准确检测电压暂降故障的目的。     

试析供电企业管理中的法律风险及防范措施

供电企业服务于公众事业,在营运过程中承担着较高的法律风险。文章首先分析了供电企业法律风险的各种表现形式,接着就法律风险的产生根源进行论述,最后提出全面防控法律风险的对策措施,以期为提升供电企业法律风险管理水平而抛砖引玉。     

基于效率视角的亚太地区知识竞争力研究

高效率的知识生产与转化是衡量区域知识竞争力的关键要素之一。沿用全球知识竞争力测度指标体系,将知识创新过程分为知识生产和转化两个子阶段,采用超效率数据包络分析方法从效率视角对亚太33个地区的知识竞争力进行测度分析。研究发现：(1)中国地区中两阶段都处于高效率区间的只有北京,上海和天津的知识生产高效率但知识转化低效率;(2)尽管大部分地区在知识生产阶段都取得了不错的效率,但知识转化效率偏低是亚太地区面临的普遍问题;(3)上海知识投入产出结构的均衡性优于其他中国大陆地区,北京投入产出偏离程度较大,两阶段投入均存在较大波动。     

基于电能专用计量芯片ATT7022A的低压无功补偿控制器设计

以高精度三相电能专用计量芯片ATT7022A为电能信号采集芯片,及时精确采集电网各项参数,以意法半导体公司的STM32F103为主控芯片,晶闸管控制电容器组的投切,来设计低压动态无功补偿控制器,用以实现对低压线路的动态无功补偿。实验表明,该控制器能极大地提高线路的功率因数,减少线损,延长电力设备的使用寿命,进而改善电网供电质量。     

An efficient method of addressing ectopic beats: new insight into data preprocessing of heart rate variability analysis

Heart rate variability (HRV) analysis is affected by ectopic beats. An efficient method was proposed to deal with the ectopic beats. The method was based on trend correlation of the heart timing signal. Predictor of R-R interval (RRI) value at ectopic beat time was constructed by the weight calculation and the slope estimation of preceding normal RRI. The type of ectopic beat was detected and replaced by the predictor of RRI. The performance of the simulated signal after ectopic correction was tested by the standard value using power spectrum density (PSD) estimation, whereas the results of clinical data with ectopic beats were compared with the adjacent ectopic-free data. The result showed the frequency indexes after ectopy corrected had less error than other methods with the test of simulated signal and clinical data. It indicated our method could improve the PSD estimation in HRV analysis. The method had advantages of high accuracy and real time properties to recover the sinus node modulation.     

出生时段、相对年龄与学校生活质量：来自PISA-上海的经验证据

利用PISA-上海(2012)的数据,基于教育生产函数的解释框架,本文检验了学校生活中的相对年龄效应。研究发现,在严格遵守入学政策并正常升级的情况下,同一年级中相对年龄较大的学生在认知(数学、阅读和科学)和非认知(未来教育期望)等若干身心发展指标上均表现更优秀。IV估计结果表明,学校生活质量的“相对年龄效应”具有内生性,OLS/MLE低估了年龄的实际影响。     

风电类上市公司的经营现状——以华锐风电科技(集团)股份有限公司为例

本文选取华锐风电科技(集团)股份有限公司这一家具有代表性的风电类上市公司,通过分析其近几年的经营现状来研究整个风电类行业的发展趋势。以2010—2012年的年度报告及季度报告为基础,通过各种财务指标进行对比和分析,分析结果得出,华锐风电整体势态发展良好,但是由于近几年的高速发展,其业绩已有所下降,这说明作为新能源的风电类行业,尽管发展趋势已成必然,但是仍然不宜大上快上。