Meta-Analytic Structural Equation Modeling: A Two-Stage Approach.

To synthesize studies that use structural equation modeling (SEM), researchers usually use Pearson correlations (univariate r), Fisher z scores (univariate z), or generalized least squares (GLS) to combine the correlation matrices. The pooled correlation matrix is then analyzed by the use of SEM. Questionable inferences may occur for these ad hoc procedures. A 2-stage structural equation modeling (TSSEM) method is proposed to incorporate meta-analytic techniques and SEM into a unified framework. Simulation results reveal that the univariate-r, univariate-z, and TSSEM methods perform well in testing the homogeneity of correlation matrices and estimating the pooled correlation matrix. When fitting SEM, only TSSEM works well. The GLS method performed poorly in small to medium samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

用FPGA设计引擎安全监测仪实现创业

并非只有宇宙才诞生于大爆炸。目前硅谷最火的汽车电子新创企业PLX Devices也诞生于创始人的引擎爆炸。PLX最新的产品是一款能够监测汽油使用状况,鼓励节油驾驶的插入式器件。它源自公司28岁的首席执行官Paul Lowchareonkul在驾车与奔驰赛车跑坏了引擎后发明的一个空气燃油比测量仪。这两款器件均采用了赛灵思FPGA平台。     

军用无源器件的发展趋势

军工/航天和商用电子元器件市场常常被认为是两个不同的市场,但实际上,二者之间的共同之处正在不断增加。由于高可靠性业务的数量显著较少,该领域的采购商似乎把目光放在商业客户的对应型号上,当然前提是满足起码的性能要求。这些采购商开始仿照商用标准产品的客户,越来越多地通过分销商来采购所需的元器件。那些军工和航天领域的巨头不再局限于原有的垂直集成业务模式,开始象那些商业OEM厂商一样,考虑将电路板组装业务通过离岸合同制造的方式外包出去,以降低他们的成本。     

适用于沉积工艺的真空技术

半导体生产中的薄膜沉积工艺通常对真空泵的要求很严格。在该工艺中高故障率和停机现象较为普遍。iH真空泵是特别为应付恶劣的薄膜工艺环境所设计。阐述了iH系列干泵在LPCVD氮化硅工艺应用中的成功表现。     

智能功率控制产品的设计

构建和维护合适的功率环境对系统的正确运行非常关键。对功率的控制和管理越来越受到重视,无论是简单的手持式便携设备,还是多服务器机架系统,都希望能够节省能耗、降低成本。     

Aerosol-jet-printed, high-speed, flexible thin-film transistor made using single-walled carbon nanotube solution

A high-purity, surfactant-free and stable SWCNT aqueous solution was prepared using a series of chemical and physical processes. The SWCNT solution has a very limited amount of carbonaceous impurities, if any, and a total metal content of well below 500 ppb. It is stable for months without the addition of surfactant. Such SWCNT aqueous solution enables ink-jet printing of the entire fast, flexible SWCNT-based field-effect thin-film transistor (FE-TFT) at room temperature without the engagement of any traditional dry or wet chemical processes used for fabricating silicon-based transistors. High-speed SWCNT-based flexible FE-TFTs were printed using Aerosol Jet^® printing technology. The printed flexible FE-TFTs were characterized to have a current ON-OFF ratio of greater than 130 with an operation frequency of greater than 5 GHz.     

人机界面的演进

术语．“人机界面”突然间已进入技术领域专用词汇的行列,就其最基本词义而言,该术语不仅用于描述设备外观,更可以描述人与设备之间的交互过程。虽然这不是一个新概念,但是该技术能够彻底改变我们与电子设备交互方式的可用性,以及集成该技术的紧迫性表明用户对界面设计日益重视。     

实现无线设计过程的无缝协作

(上篇)在无线系统设计过程中依靠基于部门划分的方法,往往会给开发流程带来麻烦。使用系统级模型不仅可以解决诸多此类问题,而且能够大大改进设计流程。各家公司都在使用基于模型的设计,以整合不同的开发团队(例如,模拟和数字)和各个设计阶段(例如,设计和验证),从而获得巨大收益。     

升级或替换?--谈亚洲数字电视的天馈线系统

要使射频广播系统的架构能够支持数字电视系统,需要设些什么?对整个网络进行进个站点的深入研究是必需的,RFS公司无线技术小组的Mike Dallimore这样认为。本文介绍了RFS公司通过对各种因素的分析研究得出的将现有系统介级为数字电视系统的最经济方案。     

Dynamic Faults in Random-Access-Memories: Concept, Fault Models and Tests

The ever increasing trend to reduce DPM levels of memories requires tests with very high fault coverage and low cost. This paper describes an important fault class, called dynamic faults, that cannot be ignored anymore. The dynamic fault behavior can take place in the absence of the static fault behavior, for which the conventional memory tests have been constructed. The concept of dynamic fault will be established and validated for both dynamic and static Random-Access-Memories. A systematic way to develop fault models for dynamic faults will be introduced. Further, it will be shown that conventional memory tests do not necessarily detect its dynamic faulty behavior, which has been shown to exist in real designs. The paper therefore also presents new memory tests to target the dynamic fault class.