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1.
斜齿圆柱齿轮机构正确啮合的条件之一是两齿轮互相啮合轮齿的倾斜方向一致。在实际工作中,经常会遇到更换一件或两件齿轮情况,需要对其进行测绘。在测绘时,应准确确定斜齿圆柱齿轮的分度圆柱螺旋角,应尽量减小测绘误差,保证斜齿圆柱齿轮的传动质量和强度不发生太大的变化。为此,在现场总结以下几种便捷的测绘方法,仅供参考。 相似文献
2.
《科技通报》2015,(10)
在不同光照和旋转角度下进行地理特征遥感识别是测绘领域的难点,为了实现对地理地形的准确测绘,需要进行地理特征遥感识别优化设计。传统方法中,采用遥感图像边缘特征检测算法,当遥感图像出现旋转角度时,识别性能不好。针对这一问题,提出一种角点检测的地理特征遥感识别算法,并进行系统设计与实现,系统通过图像传感模块采集遥感图像,经过角点特征处理器提取图像特征。在不同光照和旋转角度,采用单尺度Harris角点检测算法对图像进行检测并提取角点,得到地理遥感特征数据采集的角点模型,基于角点检测,进行遥感识别算法改进和系统实现。实验结果表明,采用该算法和系统,地理特征遥感识别准确率高,耗时较少,提高对地理特征遥感识别性能。为实现对地理地形的准确测绘提供依据。 相似文献
3.
王培瑞 《内蒙古科技与经济》1999,(2):56-57
根据机械齿轮设计、维修及机械加工实际工作中存在的有关测绘问题,有选择地阐述了已损坏的齿轮修复、加工复制、实测及特殊问题的解决,从理论和实例介绍分析了奇数齿齿轮的各种参数、尺寸的测绘与计算,对指导生产实践能起到一定的启发和引导作用。 相似文献
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5.
本文介绍了一种基于Pro/E齿轮三维特征造型和利用Pro/Program实现齿轮的参数化设计的方法,可使设计人员能方便快捷地实现齿轮的三维特征造型设计,从而提高设计效率。 相似文献
6.
现代测绘技术的飞速发展,使测绘科学发生了巨大的变革,长期以来用测角、测距、测水准为主体的常规地面定位技术,正在逐步被以一次性确定三维坐标的、高速度、高效率、高精度的GPS技术所代替。本文就测绘技术在地质勘查中的应用谈几点认识。 相似文献
7.
本文应用有限元分析软件ABAQUS分别对螺旋角为30°、40°、45°、50°的螺旋摆动马达的螺旋齿轮进行了结构分析,得到了螺旋角对螺旋齿轮受力的影响规律,为螺旋摆动马达的设计提供了依据。 相似文献
8.
<正>齿轮加工精度对机构的传动精度、传动平稳性、可靠性等都具有十分重要的影响,因此对于提高齿轮加工精度方法的研究具有十分重要的意义。本研究的突出特点在于:利用参数化建模,只要输入齿轮设计的已知条件,如模数、齿数、压力角、齿轮宽度、轴孔直径和键槽尺寸等,PRO/E系统即可自动创建出齿轮的零件模型,将其与生产实践相结合,从而达到提高齿轮加工精度和效率的目的。此方法既可适用于斜齿轮也可适用于直齿圆柱齿轮,同时,本文所阐述的建模方法对其它类似零件的实体建模也具有重要的借鉴意义。 相似文献
9.
固高科技有限公司生产的GTS-400-PV(G)-PCI系列运动控制器,可以实现高速的点位运动。其核心由DSP和FPGA组成,可以实现高性能的控制计算。GTS-400-PV(G)-PCI系列运动控制器以IBM-PC及其兼容机为主机,提供标准的PCI总线的产品。运动控制器提供C语言等函数库和Windows动态链接库,实现复杂的控制功能。以固高卡为运动控制器,对CNC齿轮测量中心的齿轮的齿距误差和齿形误差测量及其数据处理方法开发了相应的软件系统。此软件系统由当前最广范流行的C++语言在windows环境下开发完成,分为数据交换及测量点的计算,齿距测量,齿形测量和齿轮质量分析等几个模块。 相似文献
10.
本文提出了一种基于DSP的自细分步进电机控制器系统设计与实现,该控制器利用TI公司的TMS320LF2407A DSP芯片和集成电机驱动芯片构成自细分步进电机控制系统。通过对电机转速和电机驱动芯片H桥的最优开关频率进行比较,确定电机步距角的细分数,从而实现对两台2相式步进电机的优化细分控制,在确保步进电机平稳、精确地运行的同时使电机驱动芯片工作在最佳的开关状态。 相似文献
11.
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
12.
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
13.
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
14.
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
15.
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
16.
Milton Mueller 《The Information Society》2001,17(3):151-163
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. 相似文献
17.
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.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
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. 相似文献
18.
《中国科学院院刊(英文版)》2014,(3)
<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 相似文献
19.
Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese 相似文献
20.
WANG Sijia 《中国科学院院刊(英文版)》2014,(2):192-194
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages. 相似文献