CAD／CAM技术在数控机床中的应用

为了适应今后工作和个人发展的需要,数控专业的毕业生不仅要会动手还要会动脑,需要掌控多项专业技术,应当是具有综合能力的复合型人才,CAD／CAM技术就是学生需要掌握的重要专业知识之一。CAD／CAM技术在数控铣床和加工中心机床方面应用十分广泛,尤其在复杂曲面的加工过程中,这项技术起到了主导作用。就CAD／CAM技术的发展现状、主要结构、优势及CAD／CAM软件的编程的方法作一介绍,以便让更多的人了解数控专业、关注数控专业。     

三维CAD系统开发若干问题的浅析

软件组件技术的发展为大型复杂的三维CAD／CAD系统的开发提供了极好的解决之道,它完全改变了传统CAD／CAD系统开发的低效率模式,使得该类复杂系统也可以“搭积式”的快速构建。深入研究了基于组件技术开发三维CAD系统的相关技术,介绍了具体实现方法,同时给出了系统组件层次结构．可为开发该类系统提供一定的参考。     

基于COM的CAD/CAT系统集成研究

CAT技术是独立于一般CAD、CAM技术发展的，如何有效的实现CAT与CAD的集成是一个重要的问题。传统上我们采用直接对CAT数据源操作的方式来集成CAD／CAT，这存在着软件扩展性和重用性差的缺点。如果在CAD与CAT之间建立一个统一数据接口，则可以避免这些缺陷。本文利用COM技术建立统一数据接口，实现了CAD／CAT新的集成方式。     

浅谈企业CAD信息集成和资源共享的实现

随着计算机及网络技术的发展和应用,企业已经广泛使用CAD／CAPP／CAM等技术,但它们相互独立,无法实现企业内部产品CAD信息沟通和分享。然而,企业产品信息需要统一管理,尤其是CAD图纸信息等技术文件的管理,或大到总部和各分支机构,小到各技术员之间的信息沟通和资源共享。为满足需求,针对性的推出了一套适合制造企业的CAD信息集成和资源共享的方案。     

浅谈计算机辅助制造及CAD／CAM的一体化

本文阐述了目前计算机辅助制造及CAD／CAM技术的应用状况。     

浅谈CAD／CAM在数控中的应用

CAD／CAM（计算机辅助设计及制造）构成了一个现代制造型企业计算机应用的主干。对于制造行业,设计、制造水平和产品的质量、成本及生产周期息息相关。人士设计、单件生产这种传统的设计与制造方式已无法适应工业发展的要求。采用CAD／CAM的技术已成为整个制造行业当前和将来技术发展的重点。     

CAXA在数控编程技术中的应用探讨

结合数控系统的编程方法介绍了CAXA制造工程师软件的工艺加工过程。强调了CAD／CAM在现代制造技术中的地位及重要作用。     

PDM的发展及基于PDM的CAPP系统

CAPP的开发应用既要适合我国目前的国情，也要考虑发展的需要；而PDM技术的发展，使CAPP与CAD／MRPⅡ／ERP集成成为可能。     

机械CAD技术的发展及应用

主要介绍了CAD技术的发展及应用,着重介绍了几种主流机械CAD的应用,以及CAD在机械领域中的应用,并且对机械CAD技术的最新发展和趋势作了扼要综述。     

CAD/CAM技术在粮食机械设计制造中的应用探讨

现代社会进入了互联网的时代,计算机技术正在迅速发展,CAD/CAM技术在许多领域中得到了广泛的应用。在粮食机械制造业中,CAD/CAM技术得到广泛的使用。过去的CAD技术主要是二维绘图,现在出现了三维仿真,这在很大程度上扩大了该技术的应用范围。本文对CAD技术和CAM技术进行了概述,分析了CAD/CAM技术在粮食机械设计与加工中的应用。     

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