Elemental Compositions of Over 80 Cell Phones

Over the last few years, 85 cell phones have been disassembled, ground up, dissolved, and analyzed for elemental content, mainly for information about the metals present in the phones, but also for some metalloids and nonmetals. The following list of 38 elements were detected in some or all of the phones: Be, B, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Y, Nb, Pd, Ag, In, Sn, Sb, Te, Ba, Ta, W, Pt, Au, Tl, Pb, Bi, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er. Cadmium was never detected. This paper discusses the methods used for carrying out the analysis, proposes possible sources in the telephones for the elements of interest, the reasons for the interest in most of the elements, and method repeatability.     

New binary one-generator quasi-cyclic codes

Sixteen new binary quasi-cyclic linear codes improving the best known lower bounds on minimum distance in Brouwer's tables are constructed. The parameters of these codes are [102, 26, 32], [102, 27, 30], [142, 35, 40], [142, 36, 38] [146, 36, 40], [170, 16, 72], [170, 20, 66], [170, 33, 52] [170, 36, 50], [178, 33, 56], [178, 34, 54], [182, 27, 64] [182, 36, 56], [186, 17, 76], [210, 23, 80], [254, 22, 102] Sixty cyclic and thirty quasi-cyclic codes, which attain the respective bounds in Brouwer's table and are not included in Chen's table are presented as well.     

Short-pulse Calorimetric Load for High Power Millimeter-wave Beams

A spherical compact matched load, for high vacuum operation suited for short pulses (2 MW, 0.1 s) precise measurement has been designed to test high power gyrotrons Bruschi, Gandini, Muzzini, Spinicchia, Cirant, Gittini, Granucci, Mellera, Nardone, Simonetto, and Sozzi (Fusion Eng. Des. 56–57:649–654, 2001); Bruschi, Cirant, Gandini, Granucci, Mellera, Muzzini, Nardone, Simonetto, Sozzi, and Spinicchia (Nucl. Fusion 43:1513–1519, 2003); Bruschi, Cirant, Gandini, Gittini, Granucci, Mellera, Muzzini, Nardone, Simonetto, Sozzi, Spinicchia, Angella, and Signorelli (Development of CW and short-pulse calorimetric loads for high power millimeter-wave Beams, 23rd Symposium on Fusion Technology, September 20–24, 2004, Venice, Italy). In order to enhance the power handling capability of the load and to reduce the operation problems that may arise from an excessive reflection from the load, a ray tracing code has been written to model the power distribution on the inner surface and the pattern of the reflected radiation. The outcome of this code has been used to select a more convenient profile for the spreading mirror of the load and to optimize a pre-load specially conceived to minimize the power reflected fraction.     

Reduction of earthquake risk in the United States: bridging the gapbetween research and practice

Continuing efforts under the auspices of the National Earthquake Hazards Reduction Program are under way to improve earthquake risk assessment and risk management in earthquake-prone regions of Alaska, California, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash Valley seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the earthquake risk is unacceptable     

最新一代系统节电器的综合介绍——G4 Speed Uni Saver

本文较全面地介绍系统节电器，包括生产，趋势，污染后果，浪涌型式，性能，特点，原理，应用场合，参数，各代区别，第四代的优点，装置方式，功率确定，动能区别，系统框图，使用结论等。     

Theoretical foundations of transform coding

Discusses various aspects of transform coding, including: source coding, constrained source coding, the standard theoretical model for transform coding, entropy codes, Huffman codes, quantizers, uniform quantization, bit allocation, optimal transforms, transforms visualization, partition cell shapes, autoregressive sources, transform optimization, synthesis transform optimization, orthogonality and independence, and departures form the standard model     

基于ASP.NET的网络选课系统的设计与实现

本设计为基于Dotnet技术开发的网络选课系统,引入学分制和竞分制的概念。提供学生、教师、管理员三个角色登陆系统。实现了学生选课、退课、竞买选课、查看成绩,查看选课结果,查看个人信息、课程信息、教室信息;教师查看教学计划,录入成绩;管理员维护学生、教师、课程、教室信息,设置系统状态等功能。在课程上进行了较细的分类,主要分为专业选修课、专业必修课、公共选修课、公共必修课。该系统具有操作简便,功能强大,可扩展性好等特点。为学生,教师,管理员提供简单快捷的选课工作环境。     

第七届电子封装技术国际会议(通知)

自1994年以来,两年一届的电了封装技术国际会议(ICEPT)分别在中国北京、上海和深圳等地顺利召 开。作为唯一同中国政府,权威机构,业内主导所组织和支持的电子封装技术会议,每届都吸引了大批的国内 外高校、研究机构、封装组装制造厂商、封装测试组装设备厂商、封装组装材料厂商踊跃参加,人数每次都超 过400位,包括来自近20个国家和地区的国外专家、学者和企业家等。会议议题主要集中在封装设计、封装 制造、封装测试、以及光电了封装、MEMS封装、系统及组装等领域。这是唯一由中国政府和相关业界发起 的国内最高水平、最大规模的关于电…     

基于TM影像光谱指数的棉花病害严重度估测

通过获取多时相试验区TM影像和大田同步调查棉花黄萎病,将TM影像光谱指数与病害严重度进行相关分析,建立棉花病害严重度估测模型.结果表明:随着病害严重度的增加,TM影像光谱指数B2,B4,SATVI,OSAVI,MSAVI,TSAVI,SVNSWI,SNSWIa,SNSWIb,SVNI,DNSIa,DNSIb,NDSWI...     

基于多网络的矿井智能化监管系统设计

提出一种矿井智能化监管系统设计方案,该系统包括无线传感器网络（WSN）、工业以太网络、人员定位卡、井下视频手机、监管服务器、监控计算机、数据库、中心交换机、智能化监管信息平台。系统将工业以太网络和无线传感器网络结合,构建井下有线／无线的混合通信系统进行数据传输,井上利用智能化信息监管平台实现与井下作业人员、井上管理人员、井上其他人员的数据通信和资源共享;该系统具有井下人员实时定位、井下与井上实时视频通信、矿井环境监测、智能化信息处理、矿井信息分发、资源调度、异常情况报警等功能,矿井环境监测包括对瓦斯、CO、电化学氧气、硫化氢、风速、矿压、温湿度、矿尘、噪音等环境参数的监测。     

纳米二氧化钛的液相合成

纳米二氧化钛因其化学性质稳定、难溶、无毒、无迁移性、成本低廉且具有光敏、气敏、压敏等特性,从而在电子陶瓷、半导体、催化剂、护肤品、效应颜料和传感材料等领域有着重要的应用。本文较深入地分析了溶胶-凝胶法、沉淀法、水解法、微乳液法和胶溶法等液相方法的特点以及它们的工业化新进展。在合成TiO_2的三大类工艺(气相法、液相法与高能球磨法)中,液相合成方法是最简单易行的工艺。     

视频监控标准化最新进展

关注视频监控主流国际及国内标准化组织工作，分析了ITU-T、ONVIF、IEC、ISO、PSIA、HDcctv、IEEE、3GPP、ETSI、TC100、CCSA、AVS、全国信息技术标准化技术委员会等主要标准组织的视频监控相关标准化工作进展，介绍了视频监控系统、架构、设备、编解码、安全、智能应用、大数据应用、云存储、云计算、边缘存储、边缘计算等标准化研究最新进展。在此基础上，探讨了视频监控未来的产品研发方向和标准化内容，给出了视频监控标准化路线图，提出了未来的视频监控标准化及预研方向及建议。     

3D-TSV封装技术

3D-TSV封装技术是实现多功能、高性能、高可靠且更轻、更薄、更小的系统级封装最有效的技术途径之一。3D-TSV封装关键技术包括:通孔制作、通孔薄膜淀积、磁控溅射、通孔填充、铜化学机械研磨、超薄晶圆减薄、芯片/晶圆叠层键合等。阐述了每种关键技术的工艺原理、技术特点、应用范围及发展前景,关键设备、关键材料以及TSV在三维封装技术中的应用。     

One‐Dimensional Metal‐Oxide Nanostructures: Recent Developments in Synthesis,Characterization, and Applications

1D metal‐oxide nanostructures have attracted much attention because metal oxides are the most fascinating functional materials. The 1D morphologies can easily enhance the unique properties of the metal‐oxide nanostructures, which make them suitable for a wide variety of applications, including gas sensors, electrochromic devices, light‐emitting diodes, field emitters, supercapacitors, nanoelectronics, and nanogenerators. Therefore, much effort has been made to synthesize and characterize 1D metal‐oxide nanostructures in the forms of nanorods, nanowires, nanotubes, nanobelts, etc. Various physical and chemical deposition techniques and growth mechanisms are exploited and developed to control the morphology, identical shape, uniform size, perfect crystalline structure, defects, and homogenous stoichiometry of the 1D metal‐oxide nanostructures. Here a comprehensive review of recent developments in novel synthesis, exceptional characteristics, and prominent applications of one‐dimensional nanostructures of tungsten oxides, molybdenum oxides, tantalum oxides, vanadium oxides, niobium oxides, titanium oxides, nickel oxides, zinc oxides, bismuth oxides, and tin oxides is provided.     

典型单兵作战场景与夜视镜

本文分析了典型单兵作战场景,包括战场观察、侦察与监视、目标定位与激光指示、轻武器精准射击、狙击作战、与隐蔽物后/堑壕中的目标交战、夜间跳伞和机降、夜间作战、从明亮环境进入黑/昏暗室内/地下空间作战、低能见度环境的观察/搜索/射击等.为满足上述作战需求,单兵夜视镜正发展为与可见光、激光、卫星定位、数字指北针、通信等功能模...     

三网融合产业链重构与整合

三网融合产业链是由内容提供商、网络运营商、集成服务商、设备制造商、用户等构成的具有价值增值功能的企业联盟,产业链具有立体网状、竞争合作、开放多元、相互关联的特点,三网融合产业链要加强横向、纵向和混合多元整合,建立基于规模经济、范围经济和网络经济的可竞争性市场,促进三网融合稳步发展,提高信息化服务水平。     

面向企业协作服务的新型业务架构探索与实践

系统基于自研自容器微服务架构,通过自定义轻量化协议实现终端两省一低(省电、省流量、低功耗)平台三高一低(高扩展性、高负载、高可用、低资源消耗),以办公型即时通讯录、企业融合通信、企业办公协同为基础,实现办公的移动化、平台化、社交化、业务化,全面提升员工效率,充分释放组织潜能.     

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。     

Power amplifiers and transmitters for RF and microwave

The generation of RF/microwave power is required not only in wireless communications, but also in applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active devices. Power amplifiers are incorporated into transmitters in a similarly wide variety of architectures, including linear, Kalm, envelope tracking, outphasing, and Doherty. Linearity can be improved through techniques such as feedback, feedforward, and predistortion     

电台发射台改进设计

针对电台发射台搬迁对发射台的建立做出了改进设计,发射台播出体系由拉线塔、中波发射机、音频切换和监控、光缆、数字微波、UPS、发电机组、综合布线和安全监控、测试仪器、卫星地面站、调频发射塔、调频发射机、天馈系统、应急直播室等14部分组成.