场效应管设计

本文概述了场效应管的分类和设计。设计按常规程序考虑，特殊的ＭＯＳ管还要考虑相关许多其它因素，以及理论与实践结合后的取舍。     

高压真空灭弧室的电场设计

真空灭弧室广泛用于额定电压在36kV以下的中压领域。但由于必须克服诸如电场设计等方面的一些技术问题，它很少应用于高压领域。屏蔽罩、场梯电极和主触头等各种电极装置必须予以考虑。通常，真空中的这些电极结构的耐受电压可以用电场分布出来。局部电场增强和电极面积会使耐受电压有一定程度的下降，因此必须考虑局部场强增加取决于电极材料、表面处理和老炼。有效面积与电极表面局部电场强度的平均值有关。因此，还需要实验数据来获得辅助的信息，必须出屏蔽罩和CuCr或Cu触头的雷电冲击电压。本文对被试电电极结构的电场增强因子和面积效应进行了估算，最后对高压真空灭弧室的设计结果进行了讨论。     

电压偏差计算时变压器电压提升问题研究

电压质量是电能质量重要指标,有关国家标准规定了严格的电压偏差范围,进行电力系统设计时必须严格遵守。电压偏差计算时必须考虑的变压其电压提升,本文提出了一种简便的通用的变压器电压提升值的计算方法,并举例说明了其在电压偏差计算过程中的应用。     

2003年全国大学生电子设计竞赛一等奖 电压控制LC振荡器(A题)

本设计选用西勒振荡电路作为VCO。这种电路的特点是：振荡频率由C3、C4决定，但反馈系数由C1、C2决定，解决了基本三点式振荡设计中存在的改变振荡频率必改变反馈系数的矛盾。综合考虑稳幅输出和调谐方便，本设计选用变容二极管取代C4实现本系统的核心模块VCO(图1)。     

在线表面粗糙度外差干涉仪中测量信号的自动电压控制

光外差表面粗糙度在线干涉测量仪中，待测表面粗糙度的差异，使得从待测表面返回的测量信号在幅度上有很大的起伏，而使表面粗糙度测量结果的精度大大降低。本文着重讨论了测量信号的自动电压控制的原理及设计中的考虑，所制作的自动电压控制电路输入信号峰-峰值的动态范围1mV～5V，输出信号峰一峰值最大变化小于±10mV。结出了实验结果。     

绝缘系统介质强度的试验电压

家用电子产品防电击的重要性是人所共知的,防电击的主要手段是靠绝缘系统的正确设计及其材料的选择,特别是关键绝缘件的正确设计及选择,并采用合理、正确的方法进行检验。如何在保证人身安全的同时,并兼顾到经济性,一直是生产设计及检测中要考虑的问题。国内外一直在讨论中。张斌同志于一九八六年曾在“电视技术”中简要地介绍过“家用电     

华硕W5A浓缩的精华

通常，—般把重量在1.3kg以下的笔记本电脑划分为超轻薄机型，一般光驱内置12英寸机型大都超出这条分界线，因而被称之为亚轻薄机型。超轻薄笔记本通常是全外置机型，采用超低电压版处理器等低功耗部件，扩展接口通常也是偏少，应用范围有很大的限制。而现在人们对笔记本性能要求不断提高，在重量已经不足以形成负担的前提下，优先考虑的还是一款具有更高、更全面性能的笔记本电脑，这时候，从体积、重量、性能等方面综合考虑，设计得出色的12英寸光驱内置机型无疑是最佳选择。     

常用数字万用表的检修问答

winner1222：我们常用的万用表基本都是以7106为核心做的，如830、9205、9208等表。很多厂家在设计电路时会考虑对7106采用适当的保护措施，如在电路中的IN＋与地之间接一个三极管，将电压限制在1V以内。如果出现误操作导致高电压进入，这个三极管将被击穿短路，避免7106损坏。如果发现万用表在电压挡一直显示DV的话，就检查这部分电路。芯片损坏的几率还是比较小的，     

表面电荷效应对场限环优化设计的影响

本文利用计及表面电荷的柱面结电场分布表达式，并根据场限环优化条件，首次建立了单场限环表面电荷效应优化模型，得到了考虑表面电荷效应后，优化单场限环洁构击穿电压以及优化环间距的归一化计算公式。分析了表面电荷密度对场限环结构耐压和优化环间距的影响，计算结果与文献中的数值模拟结果相符合，推得的公式可应用于场限环结构的实际设计。     

实用电源（5）

常用开关电源的变压器设计是制作电源最重要的环节之一。开关电源的变压器设计,必须从输入、输出电压范围,电路方式选择、磁芯的几何尺寸等基本参数入手加以全面考虑、系统解决。     

信息化背景下的基层档案管理质量升级措施

随着时代的进步与发展,许多先进的科学技术已经开始应用到各行各业,目前许多企业单位已经开始应用并适应信息化办公模式。在企业政府等单位中,不可避免地需要接触到大量的档案资料,信息化办公模式可以有效将此类信息资源进行整理分类,但工作人员仍需注意档案管理的有序性和有效性,避免由于档案管理失误造成档案丢失或者破坏的情况。目前许多政府企业单位已经开始应用信息化档案管理系统,该系统能够很大程度地提高档案管理的质量,提升档案管理工作的效率,从而更好地满足政府企业对档案管理的需求。文中对基层档案管理信息化的必要性进行了说明,并对当前基层档案管理信息化建设的现状进行了分析,同时对档案管理现状提出了发展措施。     

La compression d’images embarquée pour les missions spatiales

On-board space instruments produce more and more high amount of data due to the increase in both resolution and number of bits per pixel, not compensated by the reduced swath. Due to the stringent limitations (in terms of mass and power) which apply to on-board equipment, it is essential to reduce to a minimum the on-board sto-rage capacity and the on-board transmission rate needed to fullfill the mission: on-board image compression is a very powerful tool to optimise the resources. The availability, for spaceborne applications, of highly integrated circuits allows to implement on board very sophisticated real-time compression schemes and then to improve the performances of on-board compression. The whole image chain (from the sensor to the on-ground post-processing such as déconvolution and denoising) has to be considered in order to select the compression algorithm and the compression ratio. This article presents the compression algorithms, selected or currently studied, for space missions, and the methods of image quality evaluation.     

The technical communication practices of Russian and US aerospaceengineers and scientists

Two studies were conducted in order to investigate the technical communication practices of Russian and US aerospace engineers and scientists. Both studies had the same five objectives: to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communication to their professions; to determine the use and production of technical communication by aerospace engineers and scientists; to seek their views about the appropriate content of the undergraduate course in technical communication; to determine aerospace engineers' and scientists' use of libraries, technical information centers, and online databases; and to determine the use and importance of computer and information technology to them. Responses to a self-administered questionnaire that was distributed to Russian aerospace engineers and scientists at the Central Aero-Hydrodynamic Institute (TsAGI) and to their US counterparts at the NASA Ames Research Center and the NASA Langley Research Center are presented     

Office information systems: Challenge for the 80's

Today's office is plagued by problems of rising costs and low productivity. Office automation and office information systems are proposed as a possible solution to many of the information handling problems of the office. The technology is available and the market place is ready for office automation. However, several challenges need to be met before the proposed remedy can be applied effectively. Automated solutions to the different aspects of the office information handling problem need to be integrated. Models and techniques need to be developed to represent and analyze information flow in an office. Interfaces need to be developed that are easy to use and integrate many different capabilities. Finally, one must examine the impact on people of office automation and produce solutions that are acceptable to the end users. To attack these problems, human factors, software and hardware engineering techniques have to be brought to bear.     

Use of induced acceleration to quantify the (de)stabilization effect of external and internal forces on postural responses

Due to the mechanical coupling between the body segments, it is impossible to see with the naked eye the causes of body movements and understand the interaction between movements of different body parts. The goal of this paper is to investigate the use of induced acceleration analysis to reveal the causes of body movements. We derive the analytical equations to calculate induced accelerations and evaluate its potential to study human postural responses to support-surface translations. We measured the kinematic and kinetic responses of a subject to sudden forward and backward translations of a moving platform. The kinematic and kinetics served as input to the induced acceleration analyses. The induced accelerations showed explicitly that the platform acceleration and deceleration contributed to the destabilization and restabilization of standing balance, respectively. Furthermore, the joint torques, coriolis and centrifugal forces caused by swinging of the arms, contributed positively to stabilization of the Center of Mass. It is concluded that induced acceleration analyses is a valuable tool in understanding balance responses to different kinds of perturbations and may help to identify the causes of movement in different pathologies.     

沪昆高铁全线开通直播系统的设计与运用

2016年12月28日,上海至昆明高速铁路贵阳至昆明段开通运营,标志着中国又一条东西向的高铁干线沪昆高铁全线开通.在这个特别的日子里,贵州广播电视台联合中央电视台对沪昆高铁难度最大的贵州段和云南段进行现场直播,和观众朋友们一起见证了这一具有历史意义的时刻.为了让直播效果达到完美,贵州广播电视台从观众朋友的角度出发,以普通关心的问题为焦点,设计出了更贴近老百姓视觉冲击力的直播方案,保证了直播的圆满完成.     

MPLS技术在唐山有线电视综合信息网数据平台中的设计与应用

MPLS技术是一项具有多协议支持的技术，它综合利用了网络核心的交换技术和网络边缘的IP路由技术各自的优点，它将标记分配给多协议的数据桢以便在基于我展品信元的网络中传输。它能够提供现有传统IP路由技术所不能支持的要求保障QoS的业务，通过MPLS技术，我们可以提供各种新兴的增值业务，有效的实施流量工程和计费管理措施，扩展和完善更高等级的基础服务。     

一种面向云计算环境的安全管理模型

在云计算中,对大规模的资源提供一种安全有效的访问是其一个很重要的组成部分。在传统的分布式访问控制模型中．服务请求者将主体属性或能力等披露给提供资源者．访问控制决策完全取决于以资源请求者能力和安全策略为输入的一致性证明。但是。这些主体属性与能力等通常携带了大量信息。势必给云环境中的互操作带来许多安全隐患和风险。针对云环境的特点,提出一种针对云环境资源的安全模型,采用一种基于属性的访问控制技术来解决云计算环境下复杂和困难的安全问题,并且提出了一个安全管理模型来动态的决定对资源的访问控制．通过对资源属性的动态改变来达到对资源的安全访问的目的。     

Hybrid Bionic Systems for the Replacement of Hand Function

In recent years, thanks to the advancement of robotics and mechatronics, new and more effective devices for the restoration and replacement of sensory-motor function in disabled people have been developed. In all these systems, user acceptability is strictly connected to several issues such as the residual abilities of the subject, the mechatronic characteristics of the robot, and also the interface chosen to link them. It is possible to figure out different "human-interface-device" combinations [also defined as "hybrid bionic systems" (HBSs)] characterized by different properties in terms of level of hybridness, connection, and augmentation. In particular, in HBSs the interface has to be customized according to the characteristics of the robotic artefact to be controlled and to the desires and needs of the final users. In this paper, our attention has been focused on the problem of the replacement of hand function after amputation. Three HBSs characterized by different levels of complexity, dexterity, and sensorization are presented in order to show the possibility of developing acceptable and effective systems by choosing different levels of connection and hybridness (i.e., different interfaces) for different devices and applications. The following case studies are presented: 1) the use of invasive interfaces to the peripheral nervous system to control a dexterous and highly sensorized hand prosthesis; 2) the use of electromyographic signals recorded using surface electrodes to control a compliant adaptive prosthesis; and 3) the use of a foot interface to control a two-degrees-of-freedom prosthesis. The preliminary results achieved so far seem to confirm the idea that the correct choice of the proper interface while developing an HBS can increase effectiveness and usability     

Design and Performance Evaluation of a Remote Catheter Navigation System

A novel remote catheter navigation system has been developed to reduce physical stress and irradiation to the interventionalist during fluoroscopic X-ray guided catheter intervention. The unique teleoperated design of this system allows the interventionalist to apply conventional axial and radial motion, as used in current practice, to an input catheter placed in a radiation-safe location to control a second catheter placed inside the procedure room. A catheter sensor (used to measure motion of the input catheter) and a catheter manipulator (used to manipulate the second catheter) are both presented. Performance evaluation of the system was assessed by first conducting bench-top experiments to quantify accuracy and precision of both sensed and replicated motion, and then conducting two experiments to evaluate the latency from sensed to replicated motion. The first study consisted of replicating motions of prescribed motion trajectories, while the second study utilized eight operators to remotely navigate a catheter through a normal carotid model. The results show the system has the ability to sense and replicate motion to within 1 mm and 1^deg in the axial and radial directions, respectively. Remote catheter manipulation was found to be operator dependent and occurred under 300 ms. Future applications of this technology are then presented.