聚丙烯高频功率电容器

介绍了用聚丙烯材料生产的高频功率电容器特性和生产工艺，并通过与云母电容器技术数据对比证实，用聚丙烯材料生产的高频电容器可部分替代云母电容器，讨论了聚丙烯高频功率电容器的设计及目前所达到的技术水平。     

国内外云母电容器发展综述

根据近几年搜集的资料，对国内外云母电容器发展进行了综述，并结合云母电容器的特点及国情，进行了分析，提出了见解。     

云母电容器的发展

<正> 电子工业部阻容情报网第二届全国云母电容器科技情报交流会于1985年5月21日至24日在湖北省武汉市召开。来自全国近20余个从事云母电容器生产、科研和试验的主要单位代表对云母电容器的现状和发展进行了热烈讨论。本文就会议讨论内容和国内外云母电容器的发展情况作一概述。     

纵论国内外片式电容器发展趋势

本文对片式陶瓷电容器、片式钽电解电容器、片式铝电解电容器、片式有机薄膜电容器、片式云母电容器，片式微调电容器等片式电容器的发展、现状及走作了系统而扼要的阐述，分析了国内外该系列产品在生产规模、工艺技术、质量水平等方面存在的差距，探讨了我国赶超世界先进水平的奋斗目标和发展战略。     

片状化云母电容器

<正> 云母电容器在电容器总产值中当前仅占2～3％,但在高频、高稳定性、高精度和高可靠性方面,云母电容器目前和未来会继续发挥特有的优势。 为了改善云母电容器的性能,为了实现小型化,独石(又称多层)结构的云母电容器应运而生。这种电容器是在被银云母片表面留出供焊接部分,印刷一层低熔点玻璃层,迭片后在加压力条件下加热,使各层间形成一个致密整体。然后制备引出电极。这     

国内外片式电容器综述（上）

本文对全球片式陶瓷电容器、片式钽电解电容器、片式铝电解电容器片式有机薄膜电容器、片式云母电容器、片式微调电容器等各类片式电容器的发展、现状及走势作了系统而扼要的阐述，分析了国内外该系列产品在生产规模、工艺技术、质量水平等方面存在的差距，探讨了我国赶超世界先进水平的奋斗目标和发展战略。     

片式电容器产品与市场

片式电容器产品与市场当今，通信、计算机和汽车工业已成为接纳片式电容器的大市场。片式电容器已由最初的陶瓷电容器发展到今天的钽电解电容器、铝电解电容器、有机薄膜电容器、云母电容器和微调电容器。目前应用最广泛的仍是多层片式陶瓷电容器和片式钽电解电容器。日本...     

云母电容器用的一种新型浸渍料

<正> 云母电容器用的一种新型浸渍料去年三季度在国营宏明无线电器材厂研试成功并正式投入生产使用。生产云母电容器通常用地蜡作浸溃料,它是生产云母电容器的关键材料之一。以往,该广使用的地蜡是进口提纯地蜡,每年要耗去国家的大量外汇。为了把料源立足于国内,该厂对我国各厂矿生产的提纯及合成地蜡进行了系统的分析和试验。     

高精度聚苯乙烯电容器的制造工艺及其应用的研究

电子工业的飞跃发展,迫切需要大量优质电容器,以往,在要求较高的场合下,都采用云母电容器。但因云母电容器制造复杂、成本高,故需要寻求新的方向。本文指出,当使用环境温度为 70℃以下时,以聚苯乙烯电容器较为理想。 本文重点研究了解决优质高精度聚苯乙烯电容器的容量精确度、稳定度、可靠性、温度系数、损耗角、绝缘电阻、介电强度、防潮性、自然电感和机械强度等问题所采取的设计和工艺措施。此外,还介绍了高精度聚苯乙烯电容器具体应用的试验结果,并且列叙了应用时的使用条件及注意事项。     

聚碳酸酯金属膜电容器

国外制成一种聚碳酸酯金属膜电容器.这种新电容器的损耗与聚苯乙烯和云母电容器相近,但体积小了很多倍.它能在很宽的温度范围内使用.容量为1微法时电容器的尺寸为直径5/10时,长11/8时.这种     

无人作战模拟仿真中的VV＆A

根据无人作战模拟研究、开发过程中分队级作战单位建模与仿真环节上所存在的VV&A问题,从军事建模的过程与军事工程技术的角度出发,将一般仿真过程中的VV&A技术与军事作战模拟的特点以及无人作战模拟的特殊性三者有机的结合在一起,深入的探讨了在无人作战模拟仿真过程中VV&A问题的解决办法以及实现过程。通过对无人作战模拟仿真中VV&A的研究与解决,为今后的作战模拟,特别是无人作战模拟中如何解决建模及仿真过程中所存在的类似问题提出了一套系统的、科学的实现办法,具有一定的理论及实践意义。对于我军无人作战研究的深入开展以及跨越式发展具有一定的参考价值。     

Improved LUT Technique for HPA Nonlinear Pre-Distortion in OFDM Systems

In this paper, we focus on the Look-up Table (LUT) technique for the compensation of HPA nonlinear distortion. An improved LUT method is proposed with better performance compared with conventional LUT technique in terms of convergence speeds, BER and total degradation (TD). It can get over 8 dB gain in out-of-band spectrum re-growth suppression and about 0.3 dB BER performance gain than conventional LUT technique with the same iteration times. Also, we propose an actual application of HPA with pre-distorter in OFDM transmitter. Ai Bo was born in Shannxi Province in China on February 7, 1974. He received a BSc. Degree from Engineering Institute of Armed Police Force in 1997, a Master and Dr. degree from Xidian University in 2002 and 2004 in China respectively, and now working as a post dr. in Dept. of E&E, state of key lab. on microwave and digital communications in Tsinghua University in China. He has once participated in the key research project on HDTV in TEEG (Team of Engineering Expert Group) of China. He is an editorial committee member of journal of “Computer Simulations”, “Information and Electronic Engineering”, an IEEE member and a senior member of Electronics Institute of China (CIE). He has published over 60 scientific papers in his research area till now. His current interests are the research and applications of OFDM techniques with emphasis on synchronization and HPA linearization techniques. Yang Zhi-Xing graduated from Tsinghua University, P.R. China in 1970. He is now a Professor and Deputy Director of State Key Lab. on Microwave and Digital Communication at the Department of Electronic Engineering and the Director of the DTV R&D Center in Tsinghua University. As a DTV technical expert for the Chinese government, Professor Yang has also been a member of the DTV standardization Committee of China and a leader of the DTV Standardization Harmonizing Group in Ministry of Information Industry of China. His major research interests include broadband information transmission technologies and DTV broadcasting systems. Pan Chang-Yong received the B.S. and M.S. degrees from the Department of Electronic Engineering in Tsinghua University, P.R. China, in 1996 and 1999, respectively. He is now an associate professor in the Department of Electronic Engineering and a member of the DTV R&D Center in Tsinghua University. His research interests are in the areas of broadband wireless transmission systems and satellite communications. Zhang Tao-Tao was born in Shandong Province in China in 1982, he received BSc. degree from Tsinghua University in 2004 and now pursing his Master degree in Dept. of E&E, state of key lab. on microwave and digital communications in Tsinghua University in China. His research interests is the power amplifier linearization techniques. Wang Yong was born in Shannxi Province in China in 1976. He received a BSc., a Master and a Dr. Degree from Xidian University in China in 1997, 2002 and 2005, respectively, and now is an associate professor in Xidian University. He has once participated in the key research project on HDTV in TEEG (Team of Engineering Expert Group) in China and is an IEEE Member. His interests are broadband multimedia communications. Ge Jian-Hua was born in September, 1961 in JiangSu Province in China. He received the B.Sc., Master and Ph.D. degree from Xidian University in 1982, 1985 and 1989, respectively. He is now the professor in both Xidian University in Xi’an and Shanghai Jiaotong University in Shanghai. He is the senior member of Chinese Electronics Institute. He has won lots of scientific and technical prizes in China and published many papers. His interests are transmission communications and web security.     

Inventive payoff from R&D in Japanese industry: convergencewith the West

An attempt is made to determine if investment in R&D and the hiring of college-educated employees result in a higher rate of inventions. The relationship between the input of R&D and inventive output is studied in two samples of Japanese factories, 34 in 1982 and 44 in 1970. These results are compared with findings in a parallel American study. The correlations between R&D and inventive output are similar in Japan and America in the 1980s, despite some differences in the management of innovation in the two nations. Moreover, the most Westernized subsample of Japanese firms in the 1970s had correlations between R&D and invention similar to those observed in the American study. Thus, it is concluded that some degree of convergence may be taking place in R&D management strategies in the two nations     

微视频在高校计算机操作性课程中的应用探究

微视频在学校各类教育中应用越来越普遍.依据微视频的教学特点,针对高校计算机操作性课程中存在的问题,本研究依据ADDIE模型和ARCS动机理论,探索构建微视频在高校计算机操作性课程中的教学应用模型,通过教学案例展示微视频在课堂应用中教与学的过程,利用微视频提高课堂教学质量.     

Regulatory reform in the broadcasting industries of Brazil and Argentina in the 1990s

Regulatory reform has changed the organization of the broadcasting industry in Brazil and Argentina in the past decade. Although responding to a similar set of pressure, the pace, instruments, and character of reforms have been different in the 2 countries, resulting in media markets of diverse natures. This study argues that these different policy outcomes in the reform of broadcasting regulation in Brazil and Argentina reflect variations in three factors: the nature of the political system, the structure of the existing broadcasting industry, and the ideological legacy in the regulation of communication industries. The case of regulatory reform in the broadcasting industry illustrates different policy patterns in the restructuring of state-industry relations in communications and information technology industries in the 2 neighboring countries.     

A Radio Resource Allocation Scheme for Fixed Broadband Wireless Access Systems with Avoidance of Major Interferers

An improved radio resource allocation scheme with avoidance of major interferers is proposed and analyzed for the downlink of Fixed Broadband Wireless Access (FBWA) systems with full frequency reuse. The scheme is based on Enhanced Staggered Resource Allocation (ESRA) and permits the enhancement of the throughput per sector. Simulation results show a maximum downlink throughput per sector in excess of 44% and an increase of 10% with respect to ESRA is achieved, with Base Station (BS) selection procedure, while meeting a 15 dB signal-to-interference ratio (SIR). Nicholas Vaiopoulos was bornin Lamia in 1977. He received his Physics degree and his M.Sc.degree in electronics and radio-communications from the University of Athens, Greecein 2000and 2003, respectively. Currently, he is working towards his Ph.D. degree on the resource allocation techniques with reference to wireless systems at the Department of informatics and Telecommunications at the same University. His research interests include broadband communications systems, scheduling algorithms and power control techniques for wireless systems. Alexander Vavoulaswas born in Athens in 1976. He received his B.Sc. degree in physics and the M.Sc. degree in electronics and radio-communications in 2000 and 2002 respectively,both from the University of Athens, Greece. Currently he is working toward the Ph.D. degree on the radio resource allocation techniques with the same University. His research interest is focused on broadband wireless access and interference management. He is a student nmember of the IEEE. Dimitris Varoutas holds BSc. degree in Physics, M.Sc. in electronics and radio-communi cations and Ph.D. in telecommunications systems and technoeconomics, all from the University of Athens. He is a lecturer in the Department of Informatics and Telecommunications of University of Athens and an adjunct assistant professor in the Department of Telecommunications of the newly founded University of Peloponnese. He has participating in numerous European R&D projects in the RACE I &II, ACTS, Telematics, RISI and IST framework in the areas of telecommunications and Technoeconomics. He is an adviser in several organisations including OTE and EETT (Greek NRA for telecommunications) in the fields of telecommunications, broadband and mobile services, licensing, spectrum management, pricing and legislation. His research interests are optical, microwave communications and technoeconomic evaluation of network architectures and services. He has more than 30 publications in refereed journal and conferences in the area of telecommunications, optoelectronics and technoeconomics. He is a member of IEEE and serves as reviewer in several journals and conferences. Thomas Sphicopoulos received the Physics degree from Athens University in 1976, the D.E.A. degree and Doctorate in Electronics both from the University of Paris VI in 1977 and 1980 respectively, the Doctorat Es Science from the Ecole Polytechnique Federale de Lausanne in 1986. From 1976 to 1977 he worked in Thomson CSF Central Research Laboratories on Microwave Oscillators. From 1977 to 1980 he was an Associate Researcher in Thomson CSF Aeronautics Infrastructure Division. In 1980 he joined the Electromagnetism Laboratory of the Ecole Polytechnique Federal de Lausanne where he carried out research on Applied Electromagnetism. Since 1987 he is with the Athens University engaged in research on Broadband Communications Systems. In 1990 he was elected as an Assistant Professor of Communications in the Department of Informatics & Telecommunications, in 1993 as Associate Professor and since 1998 he is a Professor in the same Department. His main scientific interests are Microwave and Optical Communication Systems and Networks and Techno-economics. He has lead about 40 National and European R&D projects. He has more than 100 publications in scientific journals and conference proceedings. From 1999 he is advisor in several organisations including EETT (Greek NRA for telecommunications) in the fields of market liberalisation, spectrum management techniques and technology convergence.     

我国边缘群体科普公正问题研究

本文分析了我国流动人口、妇女、残疾人、农村人口、贫困人群等科普边缘群体的状况和成因,指出科普边缘群体低层次的科学素养和知识习得状况暴露了严重的科普公正问题,政府和社会在国家科普政策和关注重心、科普资源分配、具体的科普实践和科普实效三方面缺乏或者难以实现科普公正,最后提出了4条实现科普公正的建议。     

高校图书馆信息化建设中的难点与应对策略

高校是我国培养高素质专业人才的重要单位,而图书馆则是全校师生实现自我提升的关键场所。为更好地满足高校全体师生的自主学习需求,应做好高校图书馆信息化建设,借助先进的信息化技术,满足全体师生在图书馆中的合理需求,进一步提高校内师生的学习效率。基于对高校图书馆重要性的考虑,文中分析了高校图书馆信息化建设中的问题及对策,以期提高高校图书馆信息化建设水平,更好地发挥出图书馆在高校办学中的作用。     

Noise in solid-state devices and lasers

A survey is given of the most important noise problems in solid-state devices. Section II discusses shot noise in metal-semiconductor diodes, p-n junctions, and transistors at low injection; noise due to recombination and generation in the junction space-charge region; high-level injection effects; noise in photodiodes, avalanche diodes, and diode particle detectors, and shot noise in the leakage currents in field-effect transistors (FETs). Section III discusses thermal noise and induced gate noise in FETs; generation-recombination noise in FETs and transistors at low temperatures; noise due to recombination centers in the space-charge region(s) of FETs, and noise in space-charge-limited solid-state diodes. Section IV attempts to give a unified account of 1/f noise in solid-state devices in terms of the fluctuating occupancy of traps in the surface oxide; discusses the kinetics of these traps; applies this to flicker noise in junction diodes, transistors, and FETs, and briefly discusses flicker noise in Gunn diodes and burst noise in junction diodes and transistors. Section V discusses shot noise in the light emission of luminescent diodes and lasers, and noise in optical heterodyning. Section VI discusses circuit applications. It deals with the noise figure of negative conductance amplifiers (tunnel diodes and parametric amplifiers), and of FET, transistor, and mixer circuits. In the latter discussion capacitive up-converters, and diode, FET, and transistor mixers are dealt with.     

重庆万盛采矿区内主要农作物的光谱测量和分析

矿山开采中产生的固体废弃物和废液会使矿区土壤中富集重金属元素,进而影响矿区内的农作物生长。选择重庆市万盛区矿区作为研究区,采集红薯和南瓜的实测高光谱数据和土壤样本的重金属含量数据。通过对土壤重金属含量和农作物的红边位置偏移进行相关分析,发现不同土壤重金属含量对研究区内主要农作物的影响是不同的。可以看出,在研究区内的两种主要农作物中,红薯对矿区土壤中的重金属Cr、Mn和Cd比较敏感,而南瓜则对以上三种土壤重金属具有一定的吸收和抵抗作用。该结果可以为万盛区矿区内农作物种植的选择提供理论依据。