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1.
在机械制造和仪器制造业中,丝杆是应用比较广泛的、也是重要的机器零件.精密丝杆不仅作为精密的传动元件,还常用作精密的测量元件,一般丝杆主要用作传动元件.精密丝杆本身的精度常常直接影响精密机床和测量仪器的传动精度、定位精度和测量精度,因而对精密丝杆的加工和检测日益提出更高的要求.  相似文献   

2.
梁煊林 《科技创业月刊》2013,26(4):163-164,200
根据我公司实际工作环境,对蒸养池供气温度进行自动控制改造。针对目前现有的几种自动控制设备存在的不足,设计开发一套波纹管截止阀式自动控制设备。该设备分为控制机构和执行机构两部分,控制机构负责采集蒸养池内温度值,分析数据,并最终向执行机构发出各种控制信号。执行机构采用波纹管截止阀的形式,根据我公司具体工作环境,设计一套活动式联轴机构,把电动执行器的输出传递到波纹管截止阀,从而克服目前生产使用中遇到的问题,使蒸养池温度自动控制系统得到很好的应用。  相似文献   

3.
为了适应黄土高原和丘陵山地农林发展需要,减轻农林修剪的劳动强度,设计了一种新型自动剪枝器。该剪枝器主要由移动电源(锂电池、蓄电池)、微型异步电机、固定机构、V型定位机构、伸缩杆、曲柄连杆机构和剪刀刀具组成。经实践证明该装置具有体积小、剪枝效率强、高低空作业等特点。  相似文献   

4.
为提高生产效率与减轻工作强度,本文设计了一种应用于空调生产线空调面板装配的气动机械手。机械手由装配执行机构与自动控制系统两部分组成。装配执行机构采用气压传动方式,选用双作用活塞气缸和摆台组合具有6自由度带有冗余的机械结构,面板爪具安装有真空吸盘和缓冲弹簧具有柔性接触特性。  相似文献   

5.
扑旋翼飞行器作为一种全新布局的微型飞行器(MAV),近年来吸引了很多关注,但目前针对飞行器结构设计的研究还较为空白。本文针对这一问题,以微型扑旋翼飞行器为研究对象进行了结构设计,包括驱动装置设计、传动机构设计、扑旋机构设计和机翼设计。在完成设计后,本文还探讨了扑旋翼飞行器的制作和组装,包括不同部件的材料和加工方式。获得样机后,通过实验对扑旋翼飞行器进行验证。结果表明所设计飞行器满足要求,可为相关方向的研究提供参考。  相似文献   

6.
从材料、注塑机、时间和成型条件等方面解析精密注射中易被疏忽的技术因素,并在此基础上分析如何实现精密注射、提高产品质量,从而创造更多的产品附加价值。  相似文献   

7.
郑毅  陶钢 《中国科技纵横》2010,(8):67-68,60
弹道修正是使常规弹药具有精确化打击能力的有效手段,弹药弹道修正执行机构是弹药修正化改造的关键技术之一。本文针对弹道修正的特点,提出了一种新型弹道修正执行机构——微气流脉冲修正机构。本文设计了微气流脉冲弹道修正机构,并时该机构的试验机进行测试试验,试验结果表明微气流脉冲修正机构具有运用在低速、低旋转或非旋转的火箭弹药和迫击炮弹等弹药上的可行性。  相似文献   

8.
GDX1各执行机构中,部分采用凸轮四杆机构来完成特定的运动,如何应用半行程工装对凸轮四杆机构进行调整是很重要的一个环节,调整的好坏直接影响设备的运行稳定。  相似文献   

9.
摇椅作为一种特殊形式的椅子,可提升生活质量,又增加生活情趣,正在逐渐被作为一种休闲用品在千家万户得以使用。本文介绍了一种休闲摇椅装置,无需人工施加驱动力,接通电源便可自动实现摇椅连续摇摆的设计的新颖性,同时,在传动方面,采用凸轮传动机构,使传动更加平稳可靠。  相似文献   

10.
丝杆举升机构,相对于液压油缸举升机构,更具有平稳性、同步性、安全性。文章分析了车辆运输车在设计举升机构时遇到的难题,提出了丝杆机构设计的方案和工艺,着重分析了丝杆加工过程,通过受力分析合理地设计丝杆的牙距、扭矩等参数,计算液压马达的转速、流量、排量,从而确定一整套丝杆机构的结构和参数。该设计使车辆运输车的操作更加简单化、合理化并提升产品的合格率、保证产品使用的安全性能,延长产品的使用寿命。  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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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