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1.
全彩色LED一般是由SiC或GaN等蓝色LED与其他材料构成的红、绿色相组合,构成混合型全彩色LED泡.现各国都在采用高发光效率的SiC蓝色LED,GaP红色及绿色LED,并做成LED泡,制成包括白色发光在内的可以多色发光的全彩色LED. 相似文献
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LED由于具有节能环保、启动快速、调光效能较好等特性,因此广受市场欢迎。但因其成本较高,所以普及度又不高。主要介绍了目前LED开发商为了提升LED的发光效率,降低LED成本,提高市场普及度,采用多种方案改进LED驱动电路,从而提升LED的发光效率。 相似文献
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提出照明节能的重要性,介绍了照明的历史,对LED灯发光原理,制造工艺作了详细的描述,对白炽灯、荧光灯、LED灯的效能、使用成本进行了分析对比,对未来几年LED和荧光灯进行了消长的比较,预计LED灯在室内照明应用会得到较快的发展。列举LED灯的照明应用实例,增强人们对LED灯照明的认识,促进LED灯在室内照明的应用推广。 相似文献
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LED产业是天津市战略新兴产业,而专利水平是技术优势的重要体现,对于天津LED产业快速发展至为关键。运用专利计量分析方法,通过对天津LED专利申请状况、技术生命周期、技术领域等方面的分析,深入挖掘天津LED专利发展特征,并提出提升天津LED专利质量和水平的策略。 相似文献
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进入能源高消耗时代,人们开始对LED在照明领域的应用投以关注的目光,伴随着白光高亮LED的出现,—场新的产业革命——照明革命正在到来。高亮LED照明以其高效、节能、长寿命的特点,得到越来越广泛的应用。然而如何实现对高亮LED的驱动,成为目前人们急需解决的课题之一。本文介绍了高亮LED的应用,并对LED的驱动方式进行了探讨。 相似文献
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本文通过LED平板灯的结构设计,简单阐明了LED平板灯在结构设计上需要考虑的问题和注意事项,如LED灯珠的选择、线路板的设计,导光板、扩散板等部材的选择,论证了具有可市场化的LED平板灯结构设计方案,有助于工程设计人员对LED平板灯的结构设计有所了解,避免走很多弯路,降低开发费用。 相似文献
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本文介绍了LED灯工作原理及其优点,认为将LED灯应用于公路隧道照明具有明显的优势。以福州机场二期高速公路机电工程为例,分析了LED灯应用于公路隧道基本照明的经济、社会效益,提出LED灯在隧道应用中存在的问题,可为LED隧道灯的推广提供参考和依据。 相似文献
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主要介绍目前LED开发商为了加速LED的市场普及度,采用多种方案改进LED驱动电路,从而改变了LED驱动器的闪烁及寿命缺陷,提高了LED的附加价值。 相似文献
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LED技术的发展进步,特别是白光LED的研制成功,使得LED照明进入日常照明市场成为一种可能。LED照明具有发光效率高,使用寿命长,体积小,低污染等优点,随着科学技术的提高和国家“绿色照明”政策的实施,LED照明器件的成本不断降低,将来一定会取代白炽灯、日光灯等传统照明灯具,成为照明市场的主流。 相似文献
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A research 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 in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
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. 相似文献
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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
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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
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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
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Active biological molecules 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 therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
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. 相似文献
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《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
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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
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《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
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Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
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. 相似文献
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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