DC／DC变换器低频噪声及其测量技术

噪声是DC／DC变换器重要的性能指标，它限制了其在高精密电子系统中的应用。DC／DC变换器的噪声分为高频噪声和低频噪声。高频噪声包括电流纹波与热噪声。低频噪声主要成分有1/f噪声和散粒噪声。高频噪声直接影响产品性能，低频噪声除了与产品性能有关之外，还与产品质量和可靠性密切相关。本文在详细研究DC／DC变换器低频噪声测量技术的基础上，完成了对国产军用DC／DC变换器低频噪声的测量。实验结果表明，1/f噪声和散粒噪声是DC／DC变换器低频噪声的主要成分。基于此实验结果，本文对DC／DC变换器低频噪声的产生机理进行了分析，并进一步讨论了低频噪声作为DC／DC变换器质量与可靠性诊断工具可行性。     

多块DC／DC变换器同步工作的研究及应用

本文介绍了具有同步功能的多块DC/DC变换器的设计技术，分析了这种工作方式的DC/DC变换器给整机带来的优越性，并详细叙述了此类产品的研制情况。     

DC/DC变换器可靠性保障与评估新技术

由于应用条件和环境影响对DC／DC变换器的可靠性有极大影响，因此在器件可靠性评估过程中需要考虑应用的环境和应力，从而预测出相应的失效模式，并在设计和制造过程中加以消除。本文在分析了DC／DC变换器失效模式和机理的基础上，论证了稳定温度可靠性检测方法的不足之处。本文重点介绍了可靠性保障与评估的新技术。新技术包括将美国海军JSF办公室提出的预兆一安全管理（PHM）理念应用于DC／DC变换器以及抗辐照的加固技术。当这些方法被用于结合环境测试和目标元器件评估时，才能生产出高质量和高可靠性的DC／DC的变换器。     

一种DC/DC变换器的设计与实现

本文介绍了一种新颖的具有升降压功能的DC/DC变换器的设计与实现，具体地分析了该DC/DC变换器的设计（拓扑结构、工作模式和储能电感参数的设计），详细地阐述了该DC/DC变换器控制系统的原理和实现，最后给出了测试结果。     

电子负载用软开关DC/DC变换器的实现

讨论了软开关技术在电子负载DC／DC变换器中的应用，并介绍了利用数字信号处理器实现的移相控制方法，研制了以TMS320F240为控制核心的6kW DC/DC变换器样机。     

电源模块的输入软启动电路的设计

本文就艾默生DC/DC变换器应用中输入软启动电路作了详细的研究和对比分析，其中的应用电路对艾默生DC/DC变换器用户或其它爱好者有较好的参考价值。     

降压型变换器的分叉及其混沌行为的研究

针对DC/DC开关变换器存在的非线性混沌现象,利用时间离散映射方法,导出了DC/DC Buck变换器的精确离散模型,研究DC/DC Buck变换器分叉和混沌现象动态演化过程。分析DC/DC Buck变换器的稳定性,最后通过仿真验证了系统的分叉和混沌行为。研究结果表明要使DC/DC Buck变换器工作于稳定状态,可以利用控制电压反馈系数的方法预防和消除分叉及混沌现象的发生。     

DC／DC变换器的发展与应用

介绍电压调整模块（VRM）技术、软开关技术和高频磁技术在DC/DC变换器中的应用，分析DC/DC变换器发展的关键技术，并探讨其发展的趋势。     

一种车载DC/DC变换器的研制

由于车载DC/DC变换器的特殊应用环境,要求其具有小体积、大功率、高效率、高抗震的特点。文章研究了一种车载DC/DC变换器,该变换器采用全桥移相ZVS PWM控制和倍流整流技术,能较好地满足车载大功率DC/DC变换器的各种性能指标。文中分析了该变换器的工作原理,给出了实验结果和波形。     

基于触发式电感的零电压零电流DC／DC变换器的优化

本文介绍了零电压零电流开关全桥（ZVZCS）DC＼DC变换器。通过添加辅助电路解决了软开关谐振变换器的开关损耗问题。本文叙述了用触发式电感和LC电路的实际应用来实现零电压和零电流开关全桥变换器。通过数学模型分析了在DC＼DC变换操作中变换器的参数对其的影响，用仿真进行了整流参数和工作点的优化。实现了10kW的DC＼DC变换器实验，并在文章中给出了结果。     

Job schedulers for Big data processing in Hadoop environment: testing real-life schedulers using benchmark programs

At present, big data is very popular, because it has proved to be much successful in many fields such as social media, E-commerce transactions, etc. Big data describes the tools and technologies needed to capture, manage, store, distribute, and analyze petabyte or larger-sized datasets having different structures with high speed. Big data can be structured, unstructured, or semi structured. Hadoop is an open source framework that is used to process large amounts of data in an inexpensive and efficient way, and job scheduling is a key factor for achieving high performance in big data processing. This paper gives an overview of big data and highlights the problems and challenges in big data. It then highlights Hadoop Distributed File System (HDFS), Hadoop MapReduce, and various parameters that affect the performance of job scheduling algorithms in big data such as Job Tracker, Task Tracker, Name Node, Data Node, etc. The primary purpose of this paper is to present a comparative study of job scheduling algorithms along with their experimental results in Hadoop environment. In addition, this paper describes the advantages, disadvantages, features, and drawbacks of various Hadoop job schedulers such as FIFO, Fair, capacity, Deadline Constraints, Delay, LATE, Resource Aware, etc, and provides a comparative study among these schedulers.     

谈对电子元器件企业设计开发过程中“六性”的审核

通过对电子元器件企业＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂的审核,帮助企业识别＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂,认识＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂在产品设计开发中的重要性,实现产品的＂可靠性、维修性、保障性、测试性、安全性和环境适应性＂指标。     

智能语音操控在广电端到端的系统设计及应用

在数字化中国的大背景下,在公司个人宽带与互动电视在线交费用户均突破300万户的情况下,为解决我们的用户总找不到自己喜欢看的节目,记不住频道名称和喜欢的节目,提升公司竞争力。通过对前端的点播系统、AAA系统、EPG系统、PORTAL系统、ISMP系统、媒资系统、机顶盒终端的功能进行剥离、整合和详细设计,最后完成终端用户语音操控电视直播、点播、时移、回看、页面操控、系统设置,并支持普通话和四川话方言的目的。达到提升用户体验,增加公司竞争力,促进业务的发展。系统试运行后,用户体验效果得到很大提升,完全达到预期设计目的。     

Students’ thoughts about the importance and costs of their mobile devices’ features and services

In recent years, handheld devices have become one of the fastest growing communication gadgets. Mobile technology is becoming widespread and research in this area is urgently needed. Using a survey instrument, the thoughts of male and female students regarding the importance and costs of mobile devices were investigated. It was found that students tend to consider the following features important: battery life, mp3 player, video camera, photo camera, storage memory, Bluetooth, design and elegance, clock, calendar, organizer and reminder. Also, they are eager to spend an amount of money so as their mobile device to support them. On average, both genders would pay extra money for such features. However, the majority of females think less of the price than males do. On the contrary, most of the respondents do not consider the following important: touch screen, voice commands, chat, teleconference, encryption and cryptography, common use of files, printing. Therefore, they would not spend any money for these features. Interested decision makers would try to increase their interest on such features. Moreover, all respondents appear to own a mobile phone while most of them do not have Internet connection at home. In general, some gender differences are found in the importance and costs of the mobile devices, but they are not statistically significant.     

IP网络的现状与发展趋势

论述了IP网络的现状，包括承载网、业务、协议标准和接入技术的现状。分析了IP网络的发展趋势，包括宽带化、业务多样化和分类化、网络结构层次化、统一MPLS协议标准、数据化、IP化和融合的趋势。     

移动地理信息系统在军事上的应用与实现

探讨了将先进的PDA(Personal Digital Assistant)等手持设备、移动通信技术(GRS／CDMA／GPRS)、卫星导航定位GPS技术、网络技术、嵌入技术和地理信息技术进行集成．满足GIS信息采集和数据处理的简便、实时和流动的需求。以动态的地理信息系统MGIS(Mobile GIS)为基础．为流动工作的人群提供基于位置的服务LBS。其应用将覆盖交通运输、测绘、地质矿产、城市规划、汽车自主导航、公安、部队等部门和领域。     

Progress in ZnO materials and devices

ZnO is a wide-band-gap semiconductor material that is now being developed for many applications, including ultraviolet (UV) light-emitting diodes, UV photodetectors, transparent thin-film transistors, and gas sensors. It can be grown as boules, as thin films, or as nanostructures of many types and shapes. However, as with any useful semiconductor material, its electrical and optical properties are controlled by impurities and defects. Here, we consider various important donor-type impurities, such as H, Al, Ga, and In, and acceptor-type impurities, such as N, P, As, and Sb. We also examine the effects of a few common point defects, including Zn interstitials, Zn vacancies, O vacancies, and complexes of each. The main experimental techniques of interest here include temperature-dependent Hall-effect and low-temperature photoluminescence measurements, because they alone can provide donor and acceptor concentrations and donor energies. The important topic of p-type ZnO is also considered in some detail.     

音圈电机稳速系统及图形化调试界面设计

传统像面扫描系统通常由旋转电机驱动,转动变平动,存在中间传动环节,引入摩擦、间隙、机械形变等问题,破坏系统高速运行时的稳定性。文章设计了由音圈电机驱动的像面扫描系统,具有无滞后、高响应、高加速度、高速度、控制方便等优点,实现了高精度往复运动,获得了高质量图像。在调试像面扫描控制器参数的过程中,开发了基于Labview和GEL语言的图形化调试界面,缩短了开发周期,可以推广到其他电机控制调试系统中。     

X-ray metrology for high-k atomic layer deposited HfxZr1−xO2 films

Hafnium-based dielectrics are the most promising material for SiO₂ replacement in future nodes of CMOS technology. While devices that utilize HfO₂ gate dielectrics suffer from lower carrier mobility and degraded reliability, our group has recently reported improved device characteristics with a modified Hf_xZr_1−xO₂ [R.I. Hegde, D.H. Triyoso, P.J. Tobin, S. Kalpat, M.E. Ramon, H.-H. Tseng, J.K. Schaeffer, E. Luckowski, W.J. Taylor, C.C. Capasso, D.C. Gilmer, M. Moosa, A. Haggag, M. Raymond, D. Roan, J. Nguyen, L.B. La, E. Hebert, R. Cotton, X.-D. Wang, S. Zollner, R. Gregory, D. Werho, R.S. Rai, L. Fonseca, M. Stoker, C. Tracy, B.W. Chan, Y.H. Chiu, B.E. White, Jr., in: Technical Digest - International Electron Devices Meet, vol. 39, 2005, D.H. Triyoso, R.I. Hegde, J.K. Schaeffer, D. Roan, P.J. Tobin, S.B. Samavedam, B.E. White, Jr., R. Gregory, X.-D. Wang, Appl. Phys. Lett. 88 (2006) 222901]. These results have lead to evaluation of X-ray reflectivity (XRR) for monitoring high-k film thickness and control of Zr addition to HfO₂ using measured film density. In addition, a combination of XRR and spectroscopic ellipsometry (SE) is shown to be a fast and non-intrusive method to monitor thickness of interfacial layer between high-k and the Si substrate.     

微显示器件的研究进展

微小显示和虚拟显示研究得比较多的显示器件有微CRT、LCD、OLED、微LED、LCOS、MEMS等,由于原理不同,每一种微显示器工作的场合和环境也不同,各种器件各有用武之地。LED型微显示器件作为一种全固体的主动发光器件,拥有许多优点：工作电压低、发光效率较高、响应速度快、性能稳定可靠、工作温度范围宽等。在同一芯片上集成LED阵列技术可以很好地满足应用需求。