浅谈11KV配电线路单相接地故障的危害和预防

主要针对电力系统运行过程不稳定性和危害进行分析,总结出故障的原因,进行更好的预防。11KV配电线路在我们的电网中是最主要的线路,由于他供电线路长,经过的地形长和比较复杂,所以发生单相接地的故障也较多。由于110KV配电线路采用小电流接地系统,发生单相接地时有时不跳闸,对电网影响较大,我们必须要认真对待。     

第十一届全运会各省市田径综合实力分析

运用文献资料法、数理统计法、比较分析法和逻辑归纳法,对第11届全运会奖牌和积分进行统计分析,结果表明:从整体上来说,奖牌分布相对分散,各省市综合实力重新洗牌;速度项群中鲁、苏、粤、沪、川实力显著,耐力性项群中鲁、苏、黑优势明显,快速力量项群中翼、鲁前列,综合项目中辽独领风骚;我国田径总体水平不高,但男子110m栏、20km竞走、女子马拉松、铅球、铁饼、链球、20km竞走达到世界水平,有冲击伦敦奥运会奖牌的能力.     

世界杯视角下高水平男子足球运动攻防战术能力特征研究

摘要：采用文献资料调研、数理统计、录像观察和专家访谈等方法,以第20届世界杯足球赛参赛队和近三届世界杯前4名球队为研究对象,利用RSR法对第20届世界杯参赛球队的整体攻防实力进行综合评价,力求对当前世界高水平足球运动的攻防战术能力特征进行提炼与总结。结论：第20届世界杯足球赛荷兰队、德国队2支欧洲球队攻防综合能力最突出,法国、巴西等4支球队紧随其后。且各参赛队攻防RSR值与最终排名的相关系数R=0.669,（P＜0.01）,两者呈显著相关。根据整体攻防能力的分布特征,本届世界杯各参赛球队综合能力可为5档。当前世界足坛高水平球队的总体战术能力特征为：强调整体的协同作战;战术阵型灵活多变;球员的能力全面;球队攻守兼备。进攻战术能力特征为：传控型打法主导;战术纪律严明;传球质量突出;进攻套路丰富多样;定位球战术配合娴熟默契。防守战术能力特征为：球队战术目的的针对性与球员个人战术行动的明确性相结合;球队战术变化的多样性与球员防守战术意识的协作性完美统一;守门员全面的个人能力和优秀的决策能力体现了新时代高水平足球运动的战术要求。     

Correlations Among Five Demographic Variables and the Performance of Selected Jamaican 11th-graders on Some Numerical Problems on Energy

This study was designed to assess whether the level of performance of selected Jamaican 11th-grade physics students on some numerical problems on the energy concept was satisfactory and if there were significant differences in their performance linked to their gender, socioeconomic background (SEB), school location, English language and mathematical abilities. The 331 sampled students consisted of 213 boys and 118 girls; 197 students were from a high SEB and 134 students from a low SEB; 296 students were from seven urban schools and 35 students from three rural schools; 112, 153 and 66 of the students had high, average and low English language abilities, respectively, while 144, 81 and 106 of the students had high, average and low mathematical abilities, respectively. An Energy Concept Test (ECT) consisting of six structured numerical questions was employed for data collection. The results indicated that although the students’ level of performance was regarded as fairly satisfactory, there was a lot of room for improvement. There were statistically significant differences in the students’ performance on the ECT linked to SEB, and mathematical abilities in favour of students from a high SEB, and high mathematical abilities, respectively. There was a positive, statistically significant but weak correlation between the students’ (a) mathematical abilities, and (b) English language abilities and their performance on the ECT, while there were no correlations among their gender, school location, and SEB and their performance on the ECT.     

12种二肽衍生物的非水毛细管电泳分离研究

以新型荧光试剂2-（11H-苯[a]咔唑）乙基氯甲酸酯（BCEC-Cl）为柱前衍生试剂,采用非水毛细管电泳技术对衍生二肽进行分离.以甲醇和乙腈为溶剂,乙酸-乙酸铵为缓冲体系,采用279nm二极管阵列检测.在甲醇与乙腈体积比为7：3、乙酸铵浓度为50mmol·L^-1、乙酸浓度为0.8mol·L^-1、柱温为25℃、分离电压为28kV的条件下,实现了12种二肽衍生物的基线分离.     

Higher education in Federally Administered Tribal Areas of Pakistan after 9/11： Problems and prospects

The troubled state of affairs in the Federally Administered Tribal Areas （FATA） of Pakistan portends serious repercussions and grave consequences, destined to affect education particularly higher education in the entire tribal belt. Ironically, no extensive study has been conducted, to investigate those dimensions of FATA higher education which have been adversely affected in the aftermath of 9/11. This exploratory study examines those areas which have been badly affected as a result of current turmoil. In fact, the higher education in FATA has its own peculiar dynamics. Inherently, the entire tribal region has very few well-maintained and properly equipped colleges. Lack of adequate educational facilities, multiplied poor security environment has aggravated the entire situation. Law and order situation in the region has undermined the already dilapidated monitoring mechanism of education department. This state of affairs provides breeding ground for extremist propensities and radical tendencies. In reality, very little attention has been devoted to reform the education system in tribal areas. The whole set up needs to be rehabilitated by taking recourse due to the proactive role of international community. The paper concludes with recommendations for policy makers besides offering new avenues for further research.     

Premiums,announcement returns and desperation in high tech mergers: A growth options analysis

We examine the announcements of high tech mergers using a relatively new proxy for growth options we call “growth to book.” We find this adds significantly to help explain the premiums paid and announcement period abnormal returns when acquiring tech targets. Higher synergies are expected by managers and investors when targets have low growth options and acquirers have high growth options, resulting in higher premiums paid and either less negative or more positive abnormal returns. However, we find significant variation in the results by the relative size of the target and when low growth to book (GTB) firms acquire. While high GTB acquirers tend to pay more in premiums, low GTB acquirers can pay higher premiums and receive some of the most negative returns at announcement. We find evidence some acquisitions are motivated by desperation as these acquirers have the lowest GTB and do a disproportionate number of the relatively largest deals, receiving the worst abnormal returns at announcement.     

基于模糊控制的温湿度无线监控系统

介绍了一种用于纺纱车间的温湿度无线监控系统．以STC89C58RD＋单片机为核心实现温湿度采集和控制．通过无线传输模块PTR2000实现单片机与上位机、单片机与单片机之间的无线通信．针对现实环境中温湿度控制大时滞、非线性、难以精确建模的特点,单片机采用模糊控制算法实现对温湿度的自动控制．系统具有良好的适应性和稳定性,操作简便,较好解决了纺纱车间对温湿度要求高、人工调节不便的问题．     

世界杯足球比赛裁判员执法方式改革研究

为提高足球裁判员判罚的准确性,从而促进足球项目良性发展,采用文献资料、观察、逻辑分析等研究方法,对近几届世界杯足球比赛裁判员执法状况进行分析。研究认为:裁判员的非职业化与世界杯足球比赛的高水平化不相称,世界杯足球比赛的性质、赛场环境、技战术变化和职业性犯规的增多,为裁判员执法带来较多压力,导致比赛中误判、漏判现象频繁发生。结合世界足球职业化发展现状,提出了实现裁判员职业化或引入高科技手段、增加一名主裁判、增加两名球门线裁判等多种改革构想,力求能更好地确保比赛的准确性和公正性,净化足球场上的非道德体育行为。