SCR助柴油商用车实现国Ⅳ排放

分析了我国汽车排放法规现状,及国外先进的柴油商用车尾气SCR后处理技术应用和SCR系统机构原理,指出SCR技术是一条可供我国柴油商用车实现严格排放法规的捷径。     

浅析车用柴油机尾气排放控制技术

本文主要介绍了柴油机尾气排放的治理措施,主要从电动机辅助涡轮增压技术、废气再循环技术、电控柴油共轨喷射技术、排气后处理技术四个方面进行阐述,并指出真正实现清洁柴油机需要提高燃油品质、安装车载排放监控系统、改善燃烧过程、颗粒过滤器+尿素SCR排气后处理措施及增强人们环保意识等多措并举,才能真正改善环境。     

直列式喷油泵电控柴油喷射技术

柴油机电控燃油喷射技术的应用,在满足排放法规的条件下,能大大提高柴油机的燃油经济性、动力性和排放性能。柴油机电控燃油喷射技术与汽油机电控燃油喷射技术有许多共同之处,柴油机电控燃油喷射系统的关键技术及难点为柴油喷射电控执行器。本文介绍了直列式喷油泵电控柴油喷射系统的组成、燃油量控制原理,分析了滑套式可变预行程控制机构的结构特点和控制机理。     

船舶空气污染物排放控制系列标准、技术与应用研究

国际公约、相关地区及国家关于船舶硫氧化物(SOx)、氮氧化物(NOx)排放控制的要求越来越严格,促使工业界研究和应用各种新的减排技术和方法,减少船舶的空气污染.为了满足公约或法规的SOx排放要求,船舶可应用的减排技术包括低硫燃油、废气清洗(EGC)、气体燃料.而为了满足Tier III NOx排放,船舶可应用选择性催化还原(SCR)技术、废气再循环(EGR)技术、低压气体燃料技术等.新的减排技术在船上应用,需要完善的规范标准为支撑,一方面需要考虑如何验证其排放性能是否能达到公约/法规的要求,另一方面需要考虑减排系统在船上安装运行后,不会对船舶及其重要设备产生不可接受的危害,影响船舶的安全.     

基于SCR技术的柴油机尾气处理系统尿素喷射控制策略研究

柴油机尾气处理系统尿素喷射控制策略拟采用基于SCR模型的闭环控制策略,提高控制系统鲁棒性,更好地控制尿素喷射量,减小NH3的泄漏,并满足国五的排放法规要求。     

应用SCR技术实现欧IV车用柴油机排放标准

本文对柴油机排气后处理装置的特点与应用情况进行了研究,介绍了选择催化还原技术（SCR）的机理、系统组成及工作原理,以及为实现欧IV排放标准,采用SCR技术的现状及未来展望。     

商用车新技术的应用及前景展望

阐述了商用车新技术的应用,主要包括高压共轨柴油喷射技术、涡轮增压技术、活塞冷却喷嘴、辅助制动器、空气悬架、底盘自动集中润滑系统、CAN总线技术、车载诊断系统、轮胎智能监视系统、可溃缩式转向柱、汽车行驶记录仪、后置发动机舱自动灭火装置等,最后对商用车新技术的发展进行了展望。     

锅炉省煤器分级改造技术研究

由于锅炉机组的SCR入口的排烟温度较低,对脱硝的效率造成了影响,甚至导致脱硝装置退出运行,为了解决这一问题,通过对比多种技术方案,采用省煤器分级改造技术进行相应的改造,能够有效提高SCR入口的排烟温度,进而可以指导机组进行深度调峰,并有效改善SCR的运行效率,使得排放的烟气能够达到相应的标准。     

我国汽车排放标准及检测技术的发展

排放标准和相关法律法规是控制汽车污染物排放的依据,检测方法是控制汽车污染物排放的技术保障。本文介绍了我国汽车排放标准体系的形成过程,分析比较了各个阶段测试方法的优劣,提出今后对汽车排放控制的重点应为在用车,从中可以看出我国的排放法规在逐渐严格、不断完善,最终将与国际接轨。     

我国有了自己的汽车电喷系统

近期,我国开始实施国Ⅲ汽车排放法规,要求汽车柴油机电喷系统全面取代落后的机械式喷油系统。为此,成都汪氏威特电喷公司自主研制的“电控组合泵系统”柴油机电喷技术,成功摆脱了我国电喷市场长期依赖跨国公司的局面,也确保中国汽车柴油机制造业能在较低的成本下满足国Ⅲ以上排放法规。     

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.     

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.     

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.     

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.     

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.     

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."     

The Information Environment and Universal Service

This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment.     

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.