CPLD在柴油机压电陶瓷式电控ECU设计中的应用

压电陶瓷式柴油机电控ECU日趋复杂。CPLD用硬件原理图输入法实现控制逻辑在线编程、在线修改。在压电陶瓷ECU设计中用CPLD实现发动机选缸逻辑,充电、放电预驱动逻辑、油泵驱动逻辑。实验证实,使用CPLD前、后,ECU实现相同的功能情况下,使用CPLD的控制单元PCB面积变小,控制逻辑实现更加灵活、保密。     

一种采用FPGA实现的通用看门狗电路

为了保障嵌入式系统的实时性,提高系统的可靠性,通常采用看门狗电路对系统运行情况进行监控并在必要时对系统进行复位。文章介绍了一种用FPGA实现的看门狗电路,其配置灵活、使用简便,可以满足多种系统要求。     

基于CPLD与DSP的多路信号采集器的设计

本文设计了一个基于DSP与CPLD的多路信号采集系统,介绍了CPLD接口电路的软硬件实现,并详细描述了ST 16C 544在进行系统串口扩展中的使用。     

基于CPLD的温湿度测控系统

本文论述了一种基于CPLD的温度、湿度测控系统。设计中使用VHDL硬件描述语言进行设计开发,通过温湿度传感器将模拟量输入到ADC0809进行A/D转换,再由CPLD主芯片进行测量显示并进行智能化控制以达到测控的效果。     

基于CPLD的看门狗电路设计应用

随着逻辑器件在单板硬件设计上的普遍应用,提出一种基于逻辑实现看门狗电路的实现方案。在本文中,将就如何用逻辑实现看门狗、复位原因记录、临终遗言等功能做详细说明。     

CPLD与绝对式编码器在开关磁阻电机中的应用

本文详细介绍了复杂可编程逻辑器件(CPLD)和DSP在开关磁阻电机控制系统中的应用.CPLD的使用简化了系统结构,提高了系统工作的稳定性和可靠性.绝对式光电编码器的使用增加了系统的抗干扰能力,为高速运行下实现提前关断和提前导通提供了良好的硬件支持.     

CPLD技术的使用

文章主要介绍了CPLD器件的使用及其设计过程。采用VerilogHDL语言编写控制程序,阐明了利用VerilogHDL硬件描述语言进行CPLD开发的一般思路和方法。并通过利用MAX＋PLUSII开发软件,详细介绍了MAX＋PLUSII开发软件在现代数字电路中设计的应用。     

基于CPLD技术的瞬态信号采集系统

冲击信号是一种瞬态信号,对其进行采集和分析需要提供完善的信号触发控制、采样频率自动设置及采样点数自动控制等功能。本文在分析了实现冲击信号采集特点及原理的基础上,研究并设计了基于CPLD(复杂可编程器件)的硬件功能模块。文中在生成系统时钟上采用了基于有限状态机的方法,完全在CPLD芯片中实现分频,取代了常见的使用8254可编程芯片的做法。此外,在模块中设计了采样频率设置、采样点数自动计点等功能,同时还可以用硬件实现多通道信号自动触发的功能,可以实现超前触发、滞后触发、电平触发、沿触发、触发电平自动设置等功能。所有的触发逻辑都使用verilog硬件描述语言在CPLD芯片中实现。通过和A/D电路配合工作,硬件模块可以实现采样的自动化。     

基于CPLD的数字触发电路的设计

利用大规模可编程控制器（Complex Programmable Logic Device）CPLD,针对静止补偿器（STATCOM）对触发脉冲信号的要求,设计一种基于CPLD的正弦脉宽调制（SPW M）数字触发电路。正弦调制波的产生采用查表法,但仅将1/4周期的正弦波数据存入CPLD的内部硬件所构造的ROM中减少了系统的硬件开销,并具有脉冲封锁等功能,仿真结果证明了本设计的正确性。     

基于CPLD的出租车计费器

为了克服出租车计费系统传统设计方法的弊端,介绍了基于CPLD的出租车计费系统设计的一般思路和方法.选用Altera公司低功耗、低成本、高性能的CPLD芯片EPM7128SLC84-15,并采用软件MAX+PLUSII进行程序的的编译、功能仿真和下载.使用该方法设计的出租车计费器系统设计简单、运行可靠、易于实现.     

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.     

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.     

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.     

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.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

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.     

Prevalence of soft neurological signs in Chinese people

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.     

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.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence