电能表误接线对计量准确性的影响

在新装的电能计量装置中由于电压互感器和电流互感器的相序、极性的错误导致电能表的错误接线,造成电能计量的不准确。本文列举了三相三线电能表的几种常见的错误接线,通过向量分析推导出电能表误接线时所反映的有功、无功功率表达式,进而求出其对电能计量准确性的影响。     

电能计量错误接线更正系数计算的误差分析

电能计量接线的正确性是保证电费回收正确性的前提条件,当电能表接线错误时我们要对用户进行电量追补,更正系数计算方式的不同会带来不同的误差,本文通过两个案例进行分析对比,指出在不同接线方式及不同的计算方式下误差的大小不一样,并提出了计算的意见,给实际工作提供了参考。     

低压电能表错误接线流失电量的追补分析

在电力企业供售电过程中,电能表作为供电企业销售电能的一杆秤,它的准确与否关系着供用双方的利益。若电能表发生错误接线,就会造成电能计量失准,从而给供电企业或用户带来不明损失。我利用所学知识,结合工作中的实际,对实际运行中的三相四线有功电能表错误接线做了部分分析如下:     

三相三线电能表误接线对计量的影响

在新装计量装置中由于电流互感器相序、极性的错误导致电能表的误接线,造成电能计量的不准确。列举了几种三相三线电能表常见的误接线,通过向量分析推导出电能表误接线时所反映的有功、无功功率表达式,进而求出其对计量的影响。     

利用效验仪进行现场错误接线分析与处理

现场运行中用于贸易结算的电能表因错误接线带来的误差会造成表计计量的不准确,严重的会造成电量的丢失,从而影响电能量结算的准确性与公正性。通过利用断B相电压法和相应的接线判别,分析错误接线,利用校验仪分析具体错误接线类别并加以改正,达到正确计量并准确追补电量的目的。对于各种错误接线形式均能正确判断,利用校验仪可准确分析并改正错误接线。通过分析判断错误接线形式,并进行相应的追补电量,从而为电能的准确计量提供了技术保证。     

浅谈三相三线电能表错误接线分析

电能计量装置是用于电力企业贸易结算和企业内部经济技术指标考核的电能计量器具随着国家经济的飞速发展,客户用电量的日益增加,对电能计量装置接线的准确性要求更加严谨。计量是否准确不但影响到供电企业的形象和声誉,而且直接影响贸易结算的公正性及电力企业内部经济技术指标的制定。本人针对三相三线电能表的错误接线判断方法谈谈自己的看法。     

浅谈电能表错误接线方式下的电量更正方法

电能表的二次接线方法只有一种是正确的,但因为接线员工作的疏忽,电能表的接线不正确也时有发生,而且错误的形式也是各不相同。所以这就需要工作人员在检查用电情况的时候务必要把握好电能表错误线方式下的电量更正方法,这也是向用电客户进行电量追退的主要依据。     

基于电压互感器常见错误接线的快速分析与判断

在电能计量装置中,正确的电压互感器二次接线只有一种,但由于多种因素存在,在电能计量装置中电压互感的二次接线也会发生错误的接线现象。错误的接线将导致电能计量不准确。所以要求电能计量装置安装工作人员及正常检查人员,通过相位仪测量的数值来分析判断电压互感器错误接线方式,并及时纠正,这也是保证准确计量的重要一环。     

三相三线电能表误接线对计量的影响

探讨了三相两元件电能表在计量中的接线方式及相量分析,总结出了错误接线处理方法表,错误接线计量换算系数,论述了对电能表在带电运行中,利用给出的图表来对错误接线进行处理,并可以计算正确的计量值。     

用电能表现场校验仪检查接线的原理与分析

介绍了用电能表现场校验仪实现电能计量现场接线检查的原理和方法,分析了电能表现场校验仪可识别的接线方式。     

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.     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

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.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

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