变电站高低压母线备自投的配合方式

提出了三种实现变电站中高压母线备自投和中、低压母线备自投配合的方式。其一采用延时定值保证高压母线备自投先于低压母线备自投动作;其二采用开关量保证高压母线备自投动作过程中低压母线备自投不动作;其三在备自投全部动作过程中都对备供电源电压进行检查。     

高压厂用变压器低压分支后备保护动作分析探讨

某电厂高压厂用变压器低压分支后备保护逻辑原设计方案是当高压厂用变压器低压任一分支触发复合电压过流保护或零序过流保护动作时,高压厂用电全部失电。通过对高压厂用变压器低压分支后备保护的动作逻辑进行修改,缩小了停电范围,提高了供电的可靠性。     

厂用中压母线升压试验新方法的研究

在过去的电气设备调试试验中,对于厂用中压母线系统的调试无法做到全面性,也不能很好的保证系统的稳定。对此本文采用一种试验新方法,使得厂用中压母线在受电前,能够较为全面的模拟其受电后的安全稳定情况,对设备的缺陷做到及时的发现和有效的控制,实现了在受电后系统设备的安全可靠运行。     

10kV系统接地时PT高压熔断器熔断原因分析研究

给出了10kV母线PT高压熔断器熔断的常见原因,分析并研究了10kV线路接地时,频繁导致母线PT高压熔断器熔断的深层次原因,并提出了解决措施。     

变电站母线电容器的高压带电显示设置及改进

本文针对变电站的母线电容器无法实时监控的状况,设置了母线电容器的高压带电显示装置,便于值班人员更完善的掌握母线电容器的运行状况,确保设备安全运行。     

智能汇控装置在柘林水电厂升压站中的应用

柘林水电厂所属升压站由于处在电源侧,高压断路器的控制形式较为复杂,有母线向线路充电合、线路向母线充电合、母线向主变充电合、同期合和试验合等,因此常采用现地控制单元(LCU)来控制和监视升压站相关设备的运行情况。本文主要介绍柘林水电厂用智能汇控装置来替代LCU在水电厂升压站中的应用情况。     

电厂用高压厂用变压器故障处理分析

结合实际,针对电厂用高压厂用变压器故障处理进行了论述。     

新能源电动汽车高电压安全供电系统技术

本文研究了新能源电动汽车的高压安全系统,分析了高压安全方面故障的检测和动力电池装置的高压继电器装置进行断开操作以后母线上残余电能的应对方案,讨论其潜在的风险。并且给出一项高压安全系统的解决方案。有效补充以及改进了现有的高压安全系统的功能,确保母线上的电压得到彻底释放。实测后证明此方式可以迅速释放母线上的残余电压,显著提升电动汽车高压部分的安全等级,有效减少乘客触电的风险。     

共箱封母单相接地保护配置探讨

大型发电机组厂用高压变压器中性点一般采用经电阻接地的方式,其低压侧共箱封母发生单相接地时,零序电流较大,但此时高变差动保护可能不会动作;且配置的“零序过流保护”也只动作出口跳厂用电源开关,不能完全切除故障,形成零序保护动作死区。衣文就厂用高压变压器低压侧共箱封母单相接地时零序保护配置进行探讨,达到消除该死区的目的。     

高阻抗型差动保护SEL587Z的整定

山东核电一期工程2×1250MW核电机组厂用中压母线保护采用SEL587Z高阻抗型差动保护。本文介绍了高阻抗型差动保护的基本原理及SEL587Z定值的整定方法。     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.