共查询到20条相似文献，搜索用时 62 毫秒
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针对电子设计研发中常常要功率分析仪进行各项电能参数的需求,设计了一种基于Cortex-M3的功率分析仪。采用Cortex-M3作为系统主控芯片,搭建交流隔离采样电路和直流采样电路及信号处理电路,并通过继电器进行采样通道的切换,采样模拟信号经由CS5460A与Cortex-M3内置AD进行数字量化计算各类用电参数,并通过LCD12864液晶实时显示具体参数。 相似文献
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这是一款基于单片机的数字电度表,主要由显示模块、CPU模块、cs5460A电能表芯片模块和前端电路调理模块部分组成。前端电路调理模块采用2mA／2mA的电流互感器和5A／2．5mA电流互感器和精密电阻实现对市电的转换,并采用RC滤波网络滤波,然后采用由美国CRYSTAL公司的新型电能计量芯片cs5460芯片实现对电能的测量与转换;显示模块用LCD1602,并利用STC89C52组成的CPU模块控制所有芯片的工作、测量、计算电能,送往显示模块进行显示。 相似文献
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文章从工程实际需要出发,在介绍无线收发一体芯片nRF2401的基础上,采用微处理器芯片PICl8F6621、交流采样技术和带有串行接口的功率/电能芯片CS5460,给出了基于nRF2401的高压交流信号无线数据采集系统的整体设计,开通过整个系统的仿真则试,其结果完全符合设计要求, 相似文献
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基于nRF2401的高压交流信号数据采集系统的设计 总被引：1，自引：0，他引：1
文章从工程实际需要出发,在介绍无线收发一体芯片nRF2401的基础上,采用微处理器芯片PIC18F6621、交流采样技术和带有串行接口的功率/电能芯片CS5460,给出了基于nRF2401的高压交流信号无线数据采集系统的整体设计,并通过整个系统的仿真测试,其结果完全符合设计要求。 相似文献
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提出一种简易的数字化判断方法,采用电能计量芯片CS5460A及PIC系列单片机,由钳形表接入电流,通过鳄鱼夹接入电压,无须电网断电,不用手动倒换接线,只要估计当前负载的性质,就能完全在线地判断48种接线方式。的设计方案还可同时应用于三相三线、三相四线电能表电参数的测量,包括电压有效值、电流有效值、有功功率、无功功率、视在功率、功率因数等。还设计了自校准系统,可进行电能表的校准。加以完善使之产品化,可作为三相现场多功能校验仪,具有广阔的市场前景。 相似文献
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结合最新计算机技术、网络技术、通讯技术,介绍了设计嵌入式系统网络接口模块所需要的核心以太网控制器CS8900A,分析网络底层工作机理,采用高速高性能的C8051F020微控制器与以太网控制器CS8900A和接口芯片MAX232相连接实现网络接口模块设计。该模块用途广泛,具有良好的应用前景。 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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《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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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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《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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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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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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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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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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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