Progress in electrophotography in Western Europe

A review is given of the progress in electrophotographic science and technology in Western Europe during the years 1967 to early 1971. University research work is mainly directed towards two areas: 1) the electrical and physical properties of photoconductors, such as selenium, chalcogenides, oxides, and organic materials; and 2) the sensitization of these photoconductors. Industrial research teams report on the preparation of electrophotographic layers on development and on image evaluation. A bibliography including scientific papers and patents published on this subject during said period completes this review.     

智能通信在楼宇自控系统中的应用

随着计算机技术、控制技术、通信技术及信息技术的飞速发展,人们对生活、办公环境安全性、舒适性的要求日渐增长,智能建筑应运而生。楼宇自动化控制系统是智能建筑的一个重要组成部分。通过结合具体的智能楼宇控制工程项目,在介绍系统概况的基础上,给出了系统的总体设计方案及子系统的监控方案,具有一定的实用价值。     

Advances in millimeter-wave subsystems in Japan

The authors describe the development trends and results of millimeter-wave systems in Japan in such fields as communication, radar, and measurement systems. The applications included are the W-40G waveguide transmission communication system, an automobile traffic control system using the 60-GHz band, a collision avoidance radar system for an automobile, a plasma electron density measuring system, and satellite communication. The authors describe the development of devices such as high-power FET amplifiers, traveling wave tube amplifiers (TWTAs), IMPATT amplifiers, low-noise amplifiers, and monolithic microwave integrated circuit (MMIC) devices used in constructing the millimeter-wave systems     

General Trend in Electrical Communications in Japan

Systems are currently being designed for higher reliability and greater economy. Larger transmission capacity is required to meet a rapid increase in recent communication demands instigated by the introduction of video and information communications facilities. More flexibility, to deal with the variety of communication modes to come, and smaller hardware dimensions, to overcome situations caused by the high population density, seem to be particularly sought in the communication technology of Japan. Research and development concentrate on these objectives. The following is an explanation of the present state of the art and general trends in this country.     

Progress in display-device development in Western Europe

A review of the basic research and industrial development of display devices in Western Europe during the years 1968 to early 1973 will be given. The display types considered are: 1) active displays such as cathode ray tubes, light-emitting diodes, electroluminescence cells, and gas discharge devices, and 2) passive displays such as laser displays, light valves, and ferroelectric and liquid-crystal devices.     

Designing in reliability in advanced CMOS technologies

Assessment of design implications due to degradation of CMOS devices is increasingly required in the latest technologies. This paper presents selected topics relevant to realize an efficient design-in reliability methodology in the latest generation CMOS technologies. NBTI is discussed in terms of characterization using On-The-Fly (OTF) methodology. Extension of OTF method is discussed using bias patterns to gain insights into NBTI under analog operation. A reliability simulation methodology is discussed against requirements for optimization and integration within an existing design flow. The features of this methodology are illustrated using some simple design examples.     

Switching conduction in ion-irradiated layers in GaAs

Experiments have been performed to investigate whether switching phenomena are observable in ion-irradiated GaAs. It is found that the V/I characteristics of H2+-and N+-irradiated layers show both negative resistance and switching from a high resistance to a low resistance state. Ion irradiation may thus be a useful method of fabricating switching devices.     

Electricity in China-generation in the People's Republic

Before the establishment of the People's Republic, China was a semi-colonial, semi-feudal society plagued by foreign interventions and internal power struggles. It was against this background that the electrical industry went through its infancy. Today, the People's Republic of China is facing an acute energy shortage, posing a problem which must be quickly overcome if the country's rapid industrialisation is to continue as planned. The author presents a brief history of power generation in China from 1949 to 1983 and examines possibilities for the future     

Telecommunications' role in national development in Ghana

Ghana has recognized the need for efficient and reliable telecommunication services. The widespread availability of these services will promote the nation's economic advancement and the decentralization of the government's activities. To achieve the objective of bringing telecommunications to all the people of Ghana, private sector participation is considered essential as a source of management skills, technology, and financing that will be required for the provision of services. In order to attract such participation, Ghana is putting in place the necessary policy, institutional, and regulatory frameworks to create an enabling environment for private sector investment in the telecommunication sector     

IT安全化安全IT化--信息安全产业发展问题与思考

信息安全在IT业中的角色演变 在当今信息时代,信息技术日新月异,信息产业已经成为拉动GDP增长的第一支柱产业,并以每年20%—30％的速度迅猛发展。其发展过程也经历了从传统IT向新型IT的转变,其中一个重要的转变因素便是信息安全。 1.传统IT与信息安全的关系。传统IT涵盖了五大类:通信、网络、计算机、软件、电子材料及元器件。这五类IT行业本身的发展一度呈现结构失衡:一方面过度投资到“信息高速公     

Recent Progress in Communication Theory in Japan

This paper reviews recent progress in communication theory in Japan, mainly in the past three years. The topics to be discussed include 1) waveform transmission in band-limited channels and active transmission lines, 2) source-coding problems such as optimal quantizing characteristics, delta modulation, and linear transformation, 3) transmission codes, where mainly multilevel codes have been discussed, 4) new information transmission and modulation schemes, and 5) theories of traffic and switchingsystem design.     

Noise in DMOS transistors in a BICMOS-technology

An experimental and theoretical study of the 1/f noise and the thermal noise in double-diffused MOS (DMOS) transistors in a BICMOS-technology has been carried out. By using an analytical model that consists of an enhancement MOS transistor in series with a depletion MOS transistor and a resistance, and by attributing noise sources to each device, the noise in DMOS devices is simulated accurately. Three distinct regions of operation are defined: enhancement transistor control, depletion transistor control and the linear region. In the first region, the noise is strictly determined by the enhancement transistor. It was found that the 1/f noise in this region is caused by mobility fluctuations and is very low. In the depletion transistor control region both transistors influence the total noise. Here the 1/f noise is dominated by the depletion transistor. The series resistance is only of importance in the linear region     

Zeroing in on ethical issues in nanotechnology

Setting aside exaggerated notions of both the benefits and harms to be expected from nanotechnologies, we need to focus ethical investigation on specific initiatives at the nano scale that are already underway or planned. The aims are to anticipate ethical issues likely to arise in specific cases, to foster sensitivity to ethical issues and responsibility among nano specialists and policy makers, and to stimulate interchange between nano specialists and members of the public so that the public can become involved. After clarifying what the term "nanotechnology" embraces and looking at cautionary lessons from experience with the information technologies and biotechnology, the discussion turns to the importance of anticipating consequences, intended and unintended. Although specific nano options to consider are lacking, a brief survey indicates the issues to watch out for: preventable harms, conflicts about justice and fairness, respect for persons, and more specifically, safeguards for workers in new production processes, intellectual property concerns, preservation of university values in university/industry relationships, and conflicts of interest. Three main fronts of activity are needed to address ethical issues: 1) incorporating ethics research into nano research and development enterprises; 2) devising mechanisms to involve the public so that their perspectives and concerns feed back into research and development; and 3) initiating educational efforts at every level addressing both technical aspects and ethics and social implications aspects.     

Two-wave mixing in reflection holograms in photorefractivematerials

The intensity and phase of two counterpropagating optical beams in a photorefractive material are investigated both numerically and by using an approximate analytical theory. It is shown that in the reflection regime they are two situations where coupling between the beams may be spatially dependent; in the case of nearly degenerate two-wave mixing, and when a photocurrent is present. In these situations, previously obtained results may need significant correction     

Propagation in Broadside-Coupled Suspended-Substrate Stripline in E-Plane

The spectral-domain analysis is applied to the derivation of the propagation characteristics of the even and odd mode, for the broad-sidecoupled suspended-substrate stripline (BCSSS). The characteristic impedance, based on the current-power definition, as well as the effective permittivity are evaluated. Numerical results are presented illustrating the effects of several different dimensional parameters. Numerical results indicate a large spread between even- and odd-mode impedance for thin substrates (D/A < 0.045) and stripwidths ranging 0.046<= W/B<= 0.47, suggesting tight coupling. Negligible frequency dependence on odd-mode impedance is evident, as well as significant frequency effects on even-mode impedance. Considerable dispersion is shown to be present in the odd mode for wider strips. Measured results for a low-pass filter and cascaded transitions are presented.     

Autosolitons in InSb in a magnetic field

It is shown experimentally that a longitudinal magnetic field of comparatively small magnitude substantially changes the velocity of autosolitons in indium antimonide samples and produces an appreciable redistribution of the electric field of these autosolitons. In this case, the frequency and amplitude of the current oscillations in the external circuit of the sample increases or decreases, depending on the direction of the longitudinal magnetic field. Fiz. Tekh. Poluprovodn. 32, 697–700 (June 1998) An erratum to this article is available at .     

Errors in reprojection methods in computenzed tomography

Iterative tomographic reconstruction methods have been developed which can enforce various physical constraints on the reconstructed image. An integral part of most of these methods is the repro. jection of the reconstructed image. These estimated projections are compared to the original projection data and modified according to some criteria based on a priori constraints. In this paper, the errors generated by such reprojection schemes are investigated. Bounds for these errors are derived under simple signal energy assumptions and using probabilistic assumptions on the distribution of discontinuities. These bounds can be used in the enforcement of constraints, in the determination of convergence of the iterative methods, and in the detection of artifacts.     

中国数字电视的发展现状:前景明朗现状不乐观

在计算机和移动电话给人们带来全新的数字体验以后,数字电视开始引领传统家电的数字革命,在拥有最多的电视用户的中国,这场革命刚刚开始.我国计划分2005年、2008年、2010年和2015年四个步骤来实现由模拟电视向数字电视的过渡,到2015年在国内将全面停止播放模拟电视节目.目前在3.85亿个家庭里拥有4亿台彩电,因此在今后10年内这些彩电肯定要更换成数字电视或安装机顶盒,所以我国今后将从一个巨大的模拟电视机市场转变成海量的的数字电视市场.     

移动产业2011年五大趋势:Google苹果双头垄断

新年伊始,移动产业的各种预测层出不穷,《今日美国报》专栏作家凯文·马尼(Kevin Maney)撰文,列举了2011年移动行业的五大趋势。以下为文章全文:2011年的移动行业有一些显而易见的趋势:Verizon可能会出售与其网络兼容的iPhone,苹果可能会发布新iPad,而用户则仍然有可能浪费大量时间玩《水果忍者》(Fruit Ninja)这样的游戏。