共查询到20条相似文献，搜索用时 578 毫秒
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基于FPGA及USB的数据采集系统设计 总被引：1，自引：0，他引：1
设计了一个以FPGA为主控制芯片,FLASH为存储器件以及基于USB的数据通讯接口的系统。该系统采用FPGA为控制芯片,把数据接收存储到FLASH,后期再通过USB接口把数据传输到PC机,实现了数据的脱机存储,可以满足数据采集系统的快速性和实时性要求。 相似文献
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本文提出一种以内嵌USB 2．0接口和8051 MCU的高性能单片机作为数据传输通道、以FPGA作为控制器的数据采集系统设计方案,在该方案中,主要介绍了信号采集保持原理、USB的驱动和固件开发和利用SOPC技术构建一个高速数据采集系统方案,并给出实现高速数据采集系统的软硬件开发过程。 相似文献
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以CPLD作为主控芯片,设计了一种针对USB总线的数据读写控制器。U盘通过该控制器转接到PC机的USB接口,利用控制器对USB总线上的数据进行实时监测分析,自动禁止PC机上的文件数据输出到U盘,同时不影响PC机对U盘中文件的正常读取。 相似文献
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文章基于Verilog语言设计并实现了一款基于高云FPGA芯片的DDR3 SDRAM控制器系统。本设计以GW2A55作为核心,参照JESD79-3F工业标准定义的DDR3 SDRAM时序操作、状态转换、接口定义等规范,实现了控制器的设计。设计主要分为控制层和物理传输层两个逻辑层级。通过综合验证本设计数据传输接口的速率可达到800Mhz,高负载运行下错误数据校准率为100%,芯片逻辑资源占用率低于6.5%,因此能够满足用户对高速数据传输以及可靠性和低资源占用的要求,同时具备同家族芯片可移植性强的优势,并给出了系统功能仿真的验证结果。 相似文献
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为了提高激光打标卡标刻精度和标刻速度的要求,提出一种基于USB接口激光打标控制卡的设计:控制卡首先通过PFGA主控模块控制USB传输模块,进行接收上位机传送的图像标刻数据,接着将标刻数据传输至SDRAM存储模块,在数据完成接收后,最终将激光打标卡的数据分别传输至X-Y振镜和激光器内,从而实现预设图像的标刻;激光振镜打标卡通过USB通信模块所传输的标刻数据,应按照XY2-100协议进行,FPGA控制模块选用了Cyclone III芯片,USB传输模块选用FT2232H芯片。打标卡能够快速、完整的获取PC上位机在进行图像分解后的标刻数据,并能稳定的将数据传输至激光器和X-Y振镜实现图形标刻。实验表明:该激光振镜打标卡稳定性较强、处理速度较快、标刻精度较高。 相似文献
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讨论基于以FPGA作为主控芯片、EZ-USB接口的高速数据采集系统的设计与实现。该系统采用Xilinx公司的XC2S200作为控制芯片,Cypress公司的CY8C68013芯片作为USB通信芯片,符合USB2.0协议,是一种新型的数据采集卡。 相似文献
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数据传输是现代通信过程中的一个重要环节。在数据传输过程中,不仅要求数据传输的准确率要高,而且要求速度快、连接过程简单。传统的通信技术是通过数据线和串口/并口将设备连接在一起,这样就存在连接不方便、受限条件较多等因素;并且传统的RS232串口通讯和并口通讯都存在传输速度低、接口的连接过于复杂等不足之处。而基于USB接口的数据传输系统能够较好的解决这些问题。所介绍的一种基于USB接口的数据传输系统,利用了USB接口的高传输速率、安全性高、即插即用等优点,并结合了现代数据传输技术,实现了计算机之间的高速安全的数据通讯,解决了传统通信技术带给我们的不便。 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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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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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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《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