浅析物位检测在工业生产中的意义

本文介绍了工业生产过程中采用差压式物位计、电容式物位计、核辐射式物位计、雷达式物位计等几种较新的物位检测仪表及其检测方法,对几种物位计的特点进行了分析比较。文章最后指出,物位自动检测技术对安全生产十分重要:一方面需采用新的测量原理,开发新的物位检测仪表,扩大检测的手段;另一方面需朝着微机化和智能化方向发展。     

雷达物位计在化工厂中的应用探讨

文章介绍了非接触式雷达物位计的测量原理和在化工厂里测量罐体物位的广泛应用前景。     

连续重整装置再生开工技术探讨

针对连续重整装置再生系统首次开工出现的催化剂流化问题进行了详细的分析,并采取一系列整改措施,使再生运转正常.     

ZS100数字式射频导纳物位控制器

在工农业生产自动化的过程中，物位测量是很重要的一个环节。对物位测量控制仪表的性能与精度的要求在不断的提高。而现在控制系统中使用的常规物位控制仪表(如电容式、电阻式、电接点、光电式、压力式、音叉式．超声波、射线式等)在其功能、使用环境等方面存在局限性。例如：电容式物位计在容器内物料挂壁时，容易产生误报警信号；超声波式物位计只能适应被测物界面比较平整的场合等等……。     

西门子煤仓料位计探讨

火力发电厂煤仓作为燃煤的储存设备,其料位计的准确是上煤量的主要依据.煤仓料位测量一直是个难点,目前市场上可以选择的料位计种类和品牌非常繁多,参差不齐.介绍了目前最先进的西门子公司提供的料位测量设备,该料位计主要以超声波和雷达物位计等非接触式物位测量技术为主.     

固态脱氯技术在重整催化剂再生系统的应用

针对连续重整再生气体脱氯问题,如果采用固体脱氯剂替代原碱洗和水洗系统,不仅简化了工艺流程,而且还方便了操作。固态脱氯技术的应用,可以减少再生系统腐蚀,延长运行周期,同时降低了再生气体水含量,提高了催化剂再生性能,具有较好的经济效益和环保效益。     

CB-8、CB-11半再生重整催化剂再生探讨

主要结合半再生重整催化剂CB-8、CB-11组合床工艺的工业应用,对催化剂再生过程进行了论述,并在生产实践的基础上提出了过程的关键控制点和具体的控制措施。     

氯吸附技术与碱洗技术的设计比较

在连续重整催化剂烧焦过程中,外排再生烟气含有大量HCl组分,为了达到环保排放标准,传统的处理方法是采用碱洗技术,但在装置的实际运行中容易遇到堵塞、腐蚀、PH值不易控制等问题。因此,近年来美国UOP公司开发出了新的氯处理技术-Chlorsorb技术,用来代替传统的碱洗技术。     

UOP再生器失效分析与维修策略

再生器是连续重整装置催化剂恢复活性的关键设备,特别是烧焦区的约翰逊网运行环境苛刻,是引起再生器失效的主要部件。本文从约翰逊网的运行环境、制造工艺等方面出发,分析了引起约翰逊网失效的主要原因,并依据多年的维修经验,提出几种修复的建议,对国内同类设备的维修提供了借鉴依据。     

锅炉煤粉仓料位测量实践及应用

本文阐述了科隆OPTIFLEX1300C缆式雷达物位计在锅炉粉仓物位测量控制中的应用。锅炉煤粉仓料位测量一直是困扰仪表测量一个的难题,由于煤粉料位测量本身环境差,煤质不稳定,加之测量又受粉仓的材质、几何形状、尺寸和下料口位置等因素的影响,很多仪表因为种种原因测量无法达到理想效果。我公司试使用科隆OPTIFLEX1300C缆式雷达物位计,经过两个月的运行观察,运行稳定,满足了工艺生产的需要,取得良好效果。     

铀矿山放射性污染及治理

本文阐述了我国铀矿山放射性污染的种类、来源及危害,并提出了相应的治理措施,可为我国铀矿山环境污染治理提供借鉴。     

基于辐射传导方程的三峡库区腹地地表温度的遥感反演

利用Landsat-5 TM影像,采用辐射传导方程对三峡库区腹地的地表温度进行了反演。在辐射传导方程中,对于地表比辐射率的估算,考虑到库区腹地复杂的地形和地表覆被类型的多样性,采用结合地形、水、建筑和自然表面等因素作用的经验公式进行。结果表明:①地表温度随海拔的升高呈降低趋势,其空间展布与山脉走向一致;②不同的地表覆被格局下,近地面水热交换差异较大,地表温度作为其中重要的参数也展现出显著的异质性,呈现建筑＞自然表面＞水体的基本格局。在相同海拔高度下,地表温度的高低主要取决于地表覆被的类型及其转换;③同一覆被类型间在不同海拔下的地表温度间的变化幅度因覆被类型的不同而差异显著,但随海拔的升高而降低具有显著的垂直变化规律;④验证点反演出的地表温度均是介于最低与最高气温之间的,与植被覆盖度较高区域的地表温度和气温间的关系非常接近。奉节和万县的地表温度反演值均显著高于相应站点同日平均气温,尤其是万县站高出值达7.46 ℃,主要源于站点位于城区内部,地表覆被中建筑所占比重较大,使得反演值明显高于日平均气温。地表温度的遥感反演值符合地表水热关系和垂直温度梯度规律。     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

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.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

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.