600MW锅炉引风机变频改造后的可靠性与节能分析

针对轴流引风机电耗较大,为进一步降低发电厂厂用电率,降低发电成本,进行了引风机变频改造,采用一拖一自动工／变频切换方案,在保持原有工频高压开关启停方式不变的基础上,新增加一套变频运行模式、配备旁路切换开关,引风机调节方式由静叶节流调节改为转速调节,减少了节流损失,提高了风机效率,使引风机在运行中发生的静叶开度偏差、电流偏差、戗风等一系列问题得到解决,改造后对引风机的节能效果和可靠性进行分析,保证安全经济运行。     

多点气象因子的自动监测和远程无线传输

通过AT89C51单片机芯片可实现对森林多点气象因子自动监测,并控制高频头实现远程数据的无线传输。本系统的特点是收发模块采用超外差二次变频调频制式、36MHz短波频率传送数据信息,数据格式为BCD码,可随时外接各种传感器探头,具有抗杂波干扰强、保密性好、遥控距离远、工作稳定可靠等优点,非常适用于林区森林气象因子自动监测和远程无线传输。     

WLAN智能网络优化与测试系统的开发与应用

本文介绍了WLAN技术的实现,以及WLAN自身的特点决定了它自身的优缺点,WLAN智能优化就是针对这些缺点而设定的,我们开发的智能AP通过干扰检测模块、自适应频率优化模块、自适应功率优化模块三个主要模块来实现WLAN智能优化。最终系统完成自动信道选择、自动功率选择、自动干扰避免、自动覆盖恢复、自动速率保障等功能。     

变频器与PLC在消防给水系统的应用

对变频调速消防自动给水系统进行改进。其系统采用可编程控制器（PLC）、变频器;利用PLC和变频器控制的变频调速方式,通过压力表自动调节管道压力,使水压平稳过渡,延长系统使用寿命,提高效率,降低能耗。     

恒压变频供水控制系统

供水控制系统用变频器和PLC实现了对水泵和水池的自动控制。供水自动控制中的水池水位控制、水泵自动起停控制、变频恒压供水控制的工作原理和设计方法。     

KXJT型矿用通风机自动调速装置在煤矿中的应用

介绍了KXJT型矿用通风机自动变频调速装置的设计原理与实现方法,并阐述了它有别于原有变频调速装置的优点:节能高效、自动化程度高、安全可靠、操作简单,指出了其在煤矿中进行推广的巨大优势与广阔前景。     

中央空调节能改造

随着国民经济的发展,人民生活水平的提高,空调应用日益广泛,普及空调用电占总用电量的比例在不断上升,空调能耗已占总能耗的20%左右,因而空调节能意义巨大.同时,在空调系统的设计及设备选型中均以最大负荷作为设计工况,在实际运行中空调负荷则随多种因素而变化,最小时甚至还不到设计负荷的10%,存在很大的能源浪费现象.因此空调系统加何适应在低负荷下高效能节能运行及在系统中对设备进行节能选配就成为空调节能的关键.随着变频技术的日益成熟,利用变频器、PLC、数模转换模块、温度传感器、温度模块等器件的有机结合,构成温差闭环自动控制系统,自动调节水泵的输出流量,达到节能目的的提供了可靠的技术条件.     

自适应中央空调控制系统初步设计

本文概述了基于变风量结合变制冷剂流量的小型中央空调系统设计方案,利用MCS-8051单片机和红外线传感器作为空调智能控制的核心、变频电机作为动力装置,实现了自动开关机及温度的自动控制。     

自动化技术在消防工程中的应用

详细介绍了自动消防控制系统的结构和工作原理,包括：火灾报警控制器与自动灭火系统。系统论述了各类火灾探测器的基本特点和应用场合,以及发展状况;火灾自动报警控制器的基本功能和基本形式;自动喷水灭火系统、自动泡沫灭火系统、变频恒压供水系统的工作原理、结构和功能特点.。     

变频传动控制技术在城市轨道交通车辆中的应用

随着现代电力电子器件、智能功率集成模块问世,控制理论及微电子技术的发展使异步电动机的调压变频调速得以顺利实现,从而使交流变频传动广泛应用于国民经济各部门,并正在逐步取代直流传动系统,同时随着大功率自关断器件的日趋完善和以微处理器件为核心的数字控制技术的发展更促进了交流变频传动系统在城市轨道交通车辆中的应用。     

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.