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1.
本文介绍了中国镁资源和镁产业发展概况、镁合金的主要特点及其规模化应用的曲折历史;讨论了镁合金研发及产业化过程中的重要科学技术问题和研发应用的实例。作者指出,镁合金作为结构材料的潜力尚未充分研发出来。在充分认识材料特性和环境条件的基础上,镁合金在宇航、交通、信息、装备制造业、日常生活和生物医用中都有良好的应用前景,在一些情况下,其作用是不可替代的。中国有条件由镁资源大国发展成为镁产业的强国,为此需要调整镁产业结构,扩大镁合金研发与应用研究。当前,大型、薄壁高强度镁合金铸件、镁合金变形材的研发、防腐蚀枝术的改进、产品设计理念的变更和基础数据积累是镁合金实现产业化的短板,需要重点配置研发力量。 相似文献
2.
本文介绍了中国镁资源和镁产业发展概况、镁合金的主要特点及其规模化应用的曲折历史;讨论了镁合金研发及产业化过程中的重要科学技术问题和研发应用的实例。作者指出,镁合金作为结构材料的潜力尚未充分研发出来。在充分认识材料特性和环境条件的基础上,镁合金在宇航,交通、信息,装备制造业、日常生活和生物医用中都有良好的应用前景,在一些情况下,其作用是不可替代的。中国有条件由镁资源大国发展成为镁产业的强国,为此需要调整镁产业结构,扩大镁合金研发与应用研究。当前,大型、薄壁高强度镁合金铸件、镁合金变形材的研发、防腐蚀技术的改进、产品设计理念的变更和基础数据积累是镁合金实现产业化的短板,需要重点配置研发力量。 相似文献
3.
汽车用镁合金的现状和发展前景 总被引：2，自引：0，他引：2
介绍了镁及镁合金材料及其优点,综述了镁合金在汽车工业中的应用现状.分析了镁合金在汽车工业中的发展前景,提出了镁合金应用研究中存在的一些问题以及今后的研发方向. 相似文献
4.
镁合金的研究应用及其发展 总被引：6，自引：0，他引：6
黄瑞芬 《内蒙古科技与经济》2006,(11):58-59
本文综述了镁合金的特点、种类及其性能,对镁合金在航空航天、汽车、3C等工业的应用及其现状进行了概述,提出了镁合金研究中存在的问题及其研究方向,对镁合金的发展前景进行了展望。 相似文献
5.
概述了镁及镁合金的特性和高性能稀土镁合金的特点,对高性能稀土镁合金在汽车上的应用进行了综述,对高性能稀土镁合金的发展作了展望,指出稀土镁合金的发展趋势和方向。 相似文献
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镁合金材料的应用及其发展 总被引：4，自引：0，他引：4
主要介绍了镁及镁合金材料的特性和工艺特点。重点综述了镁合金在汽车工业、航空航天业、现代兵器零部件、核工业上的应用与发展。提出了镁合金研究应用中存在的一些问题和今后的研发方向。 相似文献
8.
由于镁合金具有优良性能,它在航空、通讯、汽车等众多领域应用广泛。传统镁合金制造工艺对于制造条件要求较高,成品在科学研究中有很大的局限性。本文陈述了一种新的镁合金制备工艺,即采用喷射沉积技术加入碱土元素Ca和稀土元素Nd制备新型镁合金。新型镁合金可优化性能,加快科研进程。 相似文献
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本文概述了镁合金材料的性能、特点及镁合金的应用,介绍了镁合金的成形工艺,包括压铸、熔模铸造、消失模铸造、塑性成形、超塑性成形和半固态成形等技术,展望了其发展前景。 相似文献
11.
《中国科学院院刊(英文版)》2008,22(1):2-3
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. 相似文献
12.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
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. 相似文献
13.
《中国科学院院刊(英文版)》2008,22(1)
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." 相似文献
14.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US 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 the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
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. 相似文献
15.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
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. 相似文献
16.
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. 相似文献
17.
Puay Tang 《The Information Society》1998,14(1):19-31
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. 相似文献
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
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. 相似文献
19.
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.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
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. 相似文献
20.
Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献