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1.
为了提高无线电能传输系统的传输效率,一般将无线电能传输系统的发射线圈和接收线圈设计为对称结构。然而在实际应用中,对称结构很难满足不同的应用场合,对称结构限制其应用的扩展。本文以磁耦合谐振等效电路为基础,推导出不对称结构下的匹配条件。为不对称结构的磁耦合谐振无线电能传输系统的耦合线圈设计提供了一种方法。  相似文献   

2.
本无线电能传输装置,采用磁耦合谐振式无线能量传输方式,由发射和接收两部分构成。发射部分的驱动电路包括振荡电路和发射线圈,通过磁环电感、场效应管将电能发送出去。接收部分包括接收线圈和滤波整流电路,线圈将能量转换为交流信号,通过滤波整流转换为可以供负载利用的直流电,以实现能量的无线传输。采用的磁耦合谐振式无线能量传输的传输距离更有优势,且具有无敏感的方向性、无辐射的特点。  相似文献   

3.
无线电能传输是一种新型的电能传输技术,文章设计了一种实用的无线电能传输装置,通过线圈将电能以无线方式传输。系统包括高频振荡电路、高频功率放大电路、发射和接收线圈、高频整流滤波电路,经过实验控制变量法优化后,确定发射端和接收端相应参数,实现了无线电能传输系统的设计优化。  相似文献   

4.
本文通过研究磁耦合谐振式无线电能传输机理,设计并实现了一种无线电能传输装置,该装置包括无线发射模块和无线接收模块。装置通过无线发射模块产生高频信号,无线接收模块接收的信号经过整流滤波后供给负载使用。  相似文献   

5.
感应耦合谐振装置利用两个发生谐振耦合的电路来捕捉随距离衰减的电磁场,当发射回路和接收回路处于强耦合谐振状态下时,谐振体之间的能量交换可以达到很高的效率;远场辐射式传输方案是指在能量密度在空间中衰减十分迅速的远场空间,要使得能量能够有效的传输,必须要有能够可靠工作的大功率高频电源,还要保证发射天线有优良的方向性和相对较高的增益。  相似文献   

6.
针对磁耦合谐振式无线电能传输技术的传输效率随着频率的变化而波动的问题,采用两种不同级别频率下对装置的传输特性进行分析得到了对实际装置设计的关键指导作用,其中包括10kHz-15kHz中低频和1MHz-3MHz高频.利用不同级别频率对装置的传输效率进行跟踪测试系统传输效率。通过设计相关实验电路验证了频率特性与系统传输效率的理论分析的正确性,为提高无线电能传输功率提供有效的参考。  相似文献   

7.
无线能量传输系统由稳压电源、高频信号发生器、功率放大器、螺旋式发射天线和螺旋式接收天线五部分构成.功率放大器将高频信号发生器产生的5.68MHz信号放大后,通过螺旋式发射天线,以磁耦合共振的方式向螺旋式接收天线传送能量.螺旋天线属定向天线,发射的能量集中,有利于提高系统传输效率.系统工作于远区场,实现了能量的远距离传输.已成功实现在11m以外驱动红色发光二极管正常发光,系统功耗为1w.  相似文献   

8.
宇称-时间(PT)对称源自量子学领域中,如今被推广到电子学以及无线电能传输领域。本文基于耦合模理论,讨论了S-S补偿电路拓扑实现宇称对称无线电能传输特性。研究结果表明接收线圈位置发生变化时,其传输功率和传输效率可以在较大范围内保持不变。  相似文献   

9.
无线电能传输系统是目前电能传输的主要形式,如何减少电能损耗、缩小传输装置,这是目前无线电传输的所研究的特点与难点。在提升无线电能有效传输的过程中,利用空间两线圈的互感耦合模型,在无线电能传输系统频率特性方面进行电路分析,就可以得到接收线圈归一化的电压表达方式,在这个基础上有效传输距离被提出,最大传输距离影响因素分析即可得到线圈优化设计方法。对无线电能有效传输距离以及相关影响因素进行具体分析。  相似文献   

10.
《科技风》2016,(15)
磁共振耦合是一种新型的无线电能传输方式,打破了电磁感应和电磁波等无线电能传输方式传输距离和传输效率不可兼得的矛盾,为中距离内高效率无线电能传输提供了一种解决方案。本文利用互感耦合模型,推导出磁共振耦合无线电能传输系统磁耦合结构的等效电路模型,利用这个模型可以得到磁耦合结构的传输效率和传输功率的表达式。  相似文献   

11.
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.
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.
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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests.  相似文献   

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