基于电子元器件低频噪声特性和相关测试技术

基于电子元器件低频噪声特性测试中,针对影响低频噪声测量系统准确性的因素,提出了一种改进型的低频噪声测量方法,优化设计电子元器件低频电噪声测试系统,放大噪声测试部分噪声,并可以分析电子元器件低频噪声测试过程中的低频噪声特性,从而可以有效证实通过测试低频噪声,就能够验证电子元器件质量是否缺陷,分析电子元器件的使用可靠性.在...     

一种航天用电子元器件物资供应链系统

通过航天用电子元器件物资供应链系统的部署实施可以减少电子元器件从业人员的重复工作,减少工作失误,提升工作质量,降低库存资金,提高资金周转次数,减少短缺件,缩短电子元器件交付时间.     

泛华恒兴推出最新电子元器件老化测试系统

近日,北京泛华恒兴科技有限公司推出了电子元器件老化测试系统,该系统主要用于对探井设备电路板中多种电子元器件的入厂筛选与检验,其中包括对电阻、电容、电感等常用元器件的检测。作为专业的电子元器件老化测试系统,其可在室温至180度的任意温度点下,     

LDO在工程实践中的应用验证研究

随着国产元器件设计水平和制作工艺的提高,国产元器件与进口元器件的功性能差距日益减小,一些工程应用中的进口元器件完全可以实现国产化。从工程实践出发,服从于全面国产化的新时代要求,系统研究了开展国产低压差线性稳压器（LDO）器件应用验证时,应遵循的验证流程、可选择的验证项目,以及如何做出评价结论等内容,并重点探讨了LDO元器件级应用验证平台设计时,应注意的硬件设计问题和软件编程思想,为相关项目工程师开展国产LDO器件的应用验证工作打开了思路。     

宇航元器件电磁兼容性评估技术研究

随着元器件的集成度越来越高和功能日趋复杂,元器件的电磁兼容性(EMC)问题也愈加突显,元器件的EMC特性是评价元器件系统适应性的一个重要方面。国外宇航机构已经开展了元器件的EMC特性研究,并制定了相关标准。但在国内,无论是元器件生产厂还是元器件用户,均未对元器件的EMC特性进行系统的考核评价,给不出元器件的EMC指标。通过分析研究国内外元器件EMC评估技术发展情况,结合国内宇航元器件研制现状,从宇航应用角度出发,提出了较为规范的宇航元器件EMC评估方法和流程,并通过试验验证了该方法的可行性。     

基于MIDAS的高校电子设计竞赛元器件管理系统设计与开发

为提高高校大学生电子设计竞赛元器件管理效率,提高电子元器件利用率,设计和开发了一套智能化的电子元器件管理系统。系统基于MIDAS和ADO技术,结合高校电子设计竞赛日常培训中电子元器件的管理特点,采用多层分布式架构,对电子元器件管理系统进行了设计与实现,系统全程使用条码化管理。开发结果表明,系统具有简便易用,高效快捷等优点,将更有利于提高实验室日常实训中电子元器件的发放与回收、采购与库存预警等管理工作效率。     

航天产品电子元器件的质量控制

电子元器件是电子设备和系统的最基本单元,电子产品的可靠与否决定于电子元器件的可靠性,没有高可靠性的电子元器件,设计再好的电子产品也难以发挥其作用。文章从元器件的选择、内在质量评价、二次筛选、DPA、失效分析、元器件质量跟踪、元器件质量数据库等环节讨论了电子元器件的质量控制问题并提出了一些建议。     

微机测控系统中元器件的可靠性与选择解析

可靠性是微机测控系统中元器件在电路设计和软件编程过程中基础,并且在整个微机测控系统中元器件设计中,具有良好的选择性,与整个系统的运行有着直接性联系.本文就对微机测控系统中元器件的可靠性和选择,进行了简要的分析和阐述,同时针对影响微机测控系统中元器件可靠性的一些因素,提出了一些建议,希望在最大程度上促进了微机测控系统中元器件的正常运行.     

综述NASA的EPARTS信息系统及其经验分析

2011年,NASA总部的总工程师办公室倡导开发建立“电子元器件应用报告和跟踪系统”（Electronic Parts Applications Reporting and Tracking System,简称EPARTS）,为各中心和机构提供共同的NASA EEE元器件数据库,并且规范化EEE元器件管理程序。该系统以喷气推进实验室（JPL）的元器件数据库为原型,历时5个财年的设计、开发、调试,并在部分中心开展了部署。结合NASA的内部调研报告,本文详细介绍和剖析了EPARTS数据系统的组成以及它在NASA数据共享系统中的地位,并且分析和探讨该系统的开发和使用带给我国航天元器件数据共享系统的启示。     

PPM水平下元器件内在质量评价系统

随着元器件质量和可靠性水平的迅速提高 ,国际上对待元器件内在质量的评价问题引入了新的思路[1],采用了三项主要技术(Cpk、SPC和PPM技术)[2]。介绍根据这些新技术开发的元器件内在质量评价系统的组成及其功能。该评价系统适用于各类元器件生产。元器件生产厂家应该尽快采用这些技术 ,以便与国际要求接轨 ,尽早将产品打入国际市场。     

对于C＋＋语言考试编程题自动评分系统的研究

为了使学生适应计算机语言考试,考核学生应用C/C＋＋编写程序的能力,实现C＋＋语言考试的计算机阅卷,提出了针对C＋＋程序上机考试的自动评分系统的构建方式与算法研究。用Windows API函数做了深入的研究与分析,对如何匹配、查找程序的关键语句进行了分析和研究。该系统对C＋＋程序上机考试的客观题和主观题的计算机自动评分采用多种的方法,完成了对C＋＋语言考试的自动评分。     

一种改进的模糊核聚类红外图像分割算法

针对模糊核聚类对红外图像分割存在的不足,提出了一种改进的模糊核聚类红外图像分割算法.首先在模糊核聚类的基础上引入了隶属度和空间约束关系,有效抑制了野点;然后定义了像素对类别的认同度指数和类别对像素的排斥性度量,并将之引入到隶属度函数中,判断像素的分类合理性,提高聚类的精度,更好地分割目标和背景区域,保护目标的完整性和精确性.实验结果表明,与传统的模糊聚类分割结果相比,该算法能准确完整地分割出目标,防止背景像素和野值点对目标区域的干扰,获得良好的分割效果.     

降雨率的最坏月分区转换模式研究

最坏月分布特性是无线电系统设计和研制过程中需要考虑的重要指标,大多数无线电气象数据和传播数据只能提供年平均分布概率,这就要求提供最坏月分布和年平均分布之间的转换模式. 本文首先给出了包含累积分布和互补累积分布完整的最坏月概念. 然后分析了对流层散射传输损耗、降雨率和雨衰减、地面视距链路多径衰落等多种电波环境和传播特性的年平均和最坏月概率转换关系,并通过对比分析给出了最优的模型参数,其对应的均方根误差最小,其中对流层散射和雨衰减的均方根误差小于10%,同时论证了雨衰减的转换关系可以由降雨率的转换关系得到. 本文的研究将有力支撑无线电系统的最坏月设计.     

Optimum Distance and Power allocation Strategies for Quantum-limited Inter-Relayed FSO Communication System

In this work, we analyze the performance of a uni-directional quantum-limited inter-relay assisted free space optical link. We assume that there is no direct line of sight path between source and destination. The influence of path loss, atmospheric turbulence and pointing error impairments is considered for the analysis. The turbulence induced fading is modeled by independent but not necessarily identically distributed Gamma-Gamma fading statistics. The proposed system employs decode and forward relaying protocol assisted with channel state information. The approximate analytical expression for the probability of error is derived and illustrated by numerical plots. The asymptotic analysis for minimizing error probability in order to find optimum distance between the nodes for uniform power transmission, and for optimizing power allocated to different links, has been performed. It is shown that either distance between the nodes can be optimized for minimizing error probability when uniform power allocation is done, or optimum power allocation can be done for minimizing probability of error. Further, it helps to increase the distance for transmission between source and destination, and can make transmission possible in situations where direct link between source and destination can’t be established due to high rise buildings and other obstacles, while keeping the total transmitted power within permissible levels.     

Autonomous terrain-following for unmanned air vehicles

This paper presents an integrated guidance and control design scheme for an unmanned air vehicle (UAV), and its flight test results. The paper focuses on the longitudinal control and guidance aspects, with particular emphasis on the terrain-following problem. An introduction to the mission, and the terrain-following problem is given first. Waypoints for climb and descent are defined. Computation of the reference trajectory in the vertical plane is discussed, including a terrain-following (TF) algorithm for real-time calculation of climb/descent points and altitudes. The algorithm is particularly suited for online computation and is therefore useful for autonomous flight. The algorithm computes the height at which the vehicle should fly so that a specified clearance from the underlying terrain is always maintained, while ensuring that the vehicle’s rate of climb and rate of descent constraints are not violated. The output of the terrain-following algorithm is used to construct a smooth reference trajectory for the vehicle to track. The design of a robust controller for altitude tracking and stability augmentation of the vehicle is then presented. The controller uses elevators for pitch control in the inner loop, while the reference pitch commands are generated by the outer altitude control loop. The controller tracks the reference trajectory computed by the terrain-following algorithm. The design of an electromechanical actuator for actuating the control surfaces of the vehicle during flight is also discussed. The entire guidance and control scheme is implemented on an actual experimental vehicle and flight test results are presented and discussed.     

一种适合增强干扰消除合并算法的同步方法

在GSM/EDGE基站,通常配备两个接收天线,以便在噪声和干扰受限的场景应用的合并算法,前者采用MRC算法,后者采用IRC算法。随着小区不断变小容量要求的不断提高,同频干扰成为抑制容量的主要因素。尤其是针对典型城区应用场景,基站需要配备性能增强的干扰消除合并技术,即EIRC。由于其增益相对于IRC来说大幅提高,所以适合IRC,MRC的同步精度就会制约EIRC的使用,另外由于EIRC对时偏较敏感,需要高精度的同步算法,文中提出了针对8PSK PS业务的新同步算法,可以较好地解决这一问题。     

Advances in the design of organic resist materials

The resist materials used today in the fabrication of semiconductor devices were not expressly designed for this application. They were originally developed for use in the printing industry and were simply adopted by the electronics industry with relatively minor modifications. The performance of these resists was more than adequate for initial applications and, as a result, it was not necessary completely understand the chemistry responsible for lithographic behavior. However, the current resolution requirements and severe processing conditions in device manufacturing make it necessary to understand resist chemistry not only to maximize the performance of available materials but also to allow for the rational design of new materials.The paper discusses three topics which demonstrate that one can specifically design a resist system for optimal performance. The first deals with the generation of a negative tone image from a positive photoresist. The second topic addresses techniques for significantly reducing the time required to expose a resist. And finally, the materials requirements for the next generation of multilayer resist (MLR) systems will be discussed.     

加固计算机用开关电源的可靠性设计

对加固计算机用开关电源的可靠性设计进行了系统的探讨。结合开关电源的原理．对影响其可靠性的因素和元器件的选用原则进行了阐述,着重分析了加固计算机用开关电源的可靠性设计：电应力设计、保护电路设计、热设计、电磁兼容性设计、安全性设计和三防设计。其目的在于提高加固计算机用开关电源的可靠性。     

Frequency independent microstrip stacked antenna

The advancement of technological development in the microstrip antenna and its applications in diverse areas, have given rise to the need for a frequency agile and frequency independent microstrip antenna which could be used for the same range of frequencies without altering the system. Requirements of such nature could be met by log periodic antenna. However, in the present endeavour a frequency independent microstrip stacked antenna consisting of nine elements operating in the S-band (2.000–4.000GHz) has been proposed. The developed antenna has been experimentally tested over an achievable band of frequencies from 3.200 to 3.920GHz. The antenna performance has characteristics like E-plane radiation patterns. The 3dB beamwidth, radiated power and VSWR show very similar behaviour for the different frequencies of operation obtainable in the S-band. The coaxial-fed microstrip stacked antenna provides an operational bandwidth of approximately 23%, i.e. 3.200GHz to 3.920GHz. The VSWR for the entire operational band is around 2 whereas the gain for the antenna is found to vary from 4.00 to 8.36dB. The 3dB beamwidth has been found to fluctuate between 16.8° and 23.5°. The designed antenna can be well suited for the practical broadband applications.     

加快推进“两化”融合发展的突破口——物联网、云计算

信息化与工业化的融合是世界范围内的发展趋势,也是我国在新形势下的发展战略,需要新的信息技术为我国提供实现两化融合的新道路。我们认为,物联网和云计算技术是加快推进我国两化融合发展的突破口。物联网是帮助企业在生产经营领域实现深度信息化的手段,云计算是一种帮助企业特别是中小企业低成本地灵活实现信息化运营的模式。在介绍了物联网和云计算的相关技术和模式后,本文展示了一个节能减排应用的案例,展现了物联网和云计算技术在企业节能减排中的应用。