多芯片组件基板制造技术

多层基板是制作ＭＣＭ的关键技术，本文主要介绍ＭＣＭ＿Ｃ、ＭＣＭ－Ｄ和ＭＣＭ－Ｄ／Ｄ三种ＭＣＭ的基板制作技术。     

多芯片组件的开发与应用现状

概述了ＭＣＭ的开发现状和发展趋势，分析了ＭＣＭ的特点，介绍了ＭＣＭ的应用情况，提出了加速发展ＭＣＭ的措施。     

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新一代单边带通信机摩托罗拉推出新一代单边带通信机ＭＩＣＯＭ2,以其先进的数字信号处理技术、轻巧坚固之外形、简易操作和优异的通信效果,深受各国用户欢迎。ＭＩＣＯＭ2共有四组型号,分别为ＭＩＣＯＭ2Ｂ基本型(包括ＭＩＣＯＭ2ＢＶ对讲型)、ＭＩＣＯＭ2Ｍ海事型(包括ＭＩＣＯＭ2ＭＶ对讲型)、ＭＩＣＯＭ2Ｅ增强型和ＭＩＣＯＭ2Ｒ军事型。ＭＩＣＯＭ2ＭＶ是针对中国推出的经济实用的对讲电台,配置原厂或其它生产商供应的天调均可提供优异的通信效果。ＭＩＣＯＭ2单边带通信机更具备数据、ＧＳＰ卫星定位、传真与电话网络或ＶＨＦ/ＵＨＦ…     

迅速发展中的MCM技术

论述ＭＣＭ的基本概念及其由来；ＭＣＭ的显著优点及其迅速发展的技术背景；ＭＣＭ的种类及其对比；ＭＣＭ的主要应用领域及其市场发展。     

MMX技术概览及其应用

ＭＭＸ技术的出现掀起了多媒体计算机产业发展的新浪潮。本文介绍了ＭＭＸ技术生产的背景，ＭＭＸ的主要指令及其技术细节。讨论了国内外ＭＭＸ技术开发利用的现状及其应用前景。     

特种DRAM评述

特种ＤＲＡＭ评述钟希武特种ＤＲＡＭ一律采用外部时钟同步工作方式。它们的存储单元阵列电路和标准的ＤＲＡＭ大同小异。由于它又分为ＣＡＣＨＥＤＲＡＭ（ＣＤＲＡＭ）、增强ＤＲＡＭ（ＥＤＲＡＭ）、同步ＤＲＡＭ（ＳＤＲＡＭ）、ＲＡＭＢＵＳＤＲＡＭ（ＲＤＲＡＭ）四...     

MP3与MP Man

随身听已经过ＷＡＬＫＭａｎ、ＤＩＳｃＭａｎ、ＭＤ３代产品,目前正迈入第 ４代产品 ＭＰ Ｍａｎ, ＭＰＭａｎ将成为发烧友追求的新时尚。 ＭＰ Ｍａｎ是播放ＭＰ３格式记录的音乐内容的一种随身听。电脑爱好者对ＭＰ３这种音乐格式并不会感到陌生,因为ＭＰ３音乐光盘以其接近ＣＤ碟片重放的音质以及其超大容量深受电脑爱好者的喜爱并很快风靡起来。 ＭＰ３是音频数据压缩技术ＭＰＥＧ ｌａｙｅｒ３的缩写,ＭＰＥＧ由音频压缩和视频压缩两部分所组成,ＭＰＥＧ在音频上的压缩可分为 ＭＰＥＧ ｌａｖｅｒ１、ＭＰＥＧ ｌａｙｅｒ２、Ｍ…     

Internet收电子邮件的安全机制

近年来，Ｉｎｔｅｒｎｅｔ用户已不满足于简单电子邮件，要求提供多用途的和安全的电子邮件，为此出现了ＭＩＭＥ，ＰＥＭ，ＰＧＰＴ ＭＯＳＳ，Ｓ／ＭＩＭＥ，ＰＧＰ／ＭＩＭＥ，ＭＩＭＥｗｉｔｈＭＳＰ等多种方案。本文综述了这些方案，尤其对安全机制进行了详细的讨论。     

一种适合多媒体处理的新型芯片

介绍ＭＭＸ技术的基本内容及带有ＭＭＸ技术的微处理器，以ＭＭＸ技术在视频会议系统上的应用为例，侧重分析ＭＭＸ技术给多媒体与通信应用带来的性能改善，并对ＭＭＸ技术的应用及发展前景进行探讨。     

MCM计算机辅助设计技术

系统阐述了ＣＡＤ技术在ＭＣＭ设计中的作用、ＭＣＭ ＣＡＤ的环境及ＭＣＭ ＣＡＤ的方法和流程,指出了目前国内外ＭＣＭ ＣＡＤ技术的发展现状和发展趋势,分析了目前ＭＣＭ ＣＡＤ设计技术的研究热点。     

基于2007-2013年COSMIC掩星数据的电离层振幅闪烁研究

利用2007-2013年的COSMIC掩星数据，分析了E区与F区电离层闪烁的变化特征.发现用闪烁出现频次、闪烁发生率以及闪烁强度来表征的电离层闪烁出现规律比较相似.E区电离层闪烁在夏季半球的中纬地区最强，其次是春秋季的低纬地区和冬季半球.就经度分布来说，春秋季E区电离层闪烁呈四波结构.对F区电离层闪烁来说:南美-大西洋扇区在12月至点最为显著；非洲和太平洋扇区在6月至点最为显著；大西洋扇区在春秋分季最为显著.极区也出现中等强度的闪烁，尤其在南半球的90°E~180°E扇区较为显著.高纬E区电离层闪烁强度随太阳活动的增强而增强，而低纬和南半球的中纬E区闪烁随太阳活动的增强而减弱.高纬和低纬F区闪烁随太阳活动的增强而增强，而中纬F区电离层闪烁对太阳活动无显著依赖关系.对于赤道区来说，北半球60°W~60°E经度区闪烁强度随太阳活动的变化最为显著，其次是南半球60°E~210°E附近；而对于高纬地区来说，F区闪烁强度随太阳活动的变化最为显著的区域在南半球60°E~210°E附近.     

Effect of photovoltage on current flow in metal-semiconductor schottky-barrier contacts

It is shown that changes in device characteristics and an increase in the light-to-electrical energy conversion efficiency in metal-semiconductor Schottky barrier contacts are associated with a peripheral electric field built into the contact. For contacts with longer perimeters, variations in device characteristics and the light-to-electrical energy conversion efficiency are significantly larger. Since the photovoltage and peripheral electric fields in the contact region are codirected with the intrinsic electric field of the space-charge region, contact illumination results in a larger increase in the “dead” zone in forward portions of current-voltage characteristics, a larger decrease in the effective Schottky barrier height, and an increase in the field electron emission. An increase in the reverse field emission under photovoltage leads to an increase in the recombination current in the space-charge region, which provides dc photocurrent flow in the circuit.     

Inventive payoff from R&D in Japanese industry: convergencewith the West

An attempt is made to determine if investment in R&D and the hiring of college-educated employees result in a higher rate of inventions. The relationship between the input of R&D and inventive output is studied in two samples of Japanese factories, 34 in 1982 and 44 in 1970. These results are compared with findings in a parallel American study. The correlations between R&D and inventive output are similar in Japan and America in the 1980s, despite some differences in the management of innovation in the two nations. Moreover, the most Westernized subsample of Japanese firms in the 1970s had correlations between R&D and invention similar to those observed in the American study. Thus, it is concluded that some degree of convergence may be taking place in R&D management strategies in the two nations     

Modulation of intersubband absorption in tunnel-coupled quantum wells in electric fields

Modulation of absorption of middle-infrared radiation in double tunneling-coupled quantum wells in longitudinal electric fields is studied. A specific feature of the quantum wells is the small separation in energy between the two lower levels. As a consequence, the levels may exhibit “anticrossing” even in low transverse electric fields. An interpretation of the change in intersubband absorption is suggested. The interpretation is based on the assumption that a transverse electric-field component may appear in the structure. The change in the absorption coefficient is calculated taking into account the redistribution of electrons between size-quantization subbands and the changes in the temperature of electrons in the subbands in the longitudinal electric field, as well as the changes in the optical matrix elements, the energies of transitions, and the concentrations of electrons in the subbands in the transverse electric field. The possibility of using the structure for the efficient modulation of middle-infrared light with the photon energy 136 meV is shown.     

重庆万盛采矿区内主要农作物的光谱测量和分析

矿山开采中产生的固体废弃物和废液会使矿区土壤中富集重金属元素,进而影响矿区内的农作物生长。选择重庆市万盛区矿区作为研究区,采集红薯和南瓜的实测高光谱数据和土壤样本的重金属含量数据。通过对土壤重金属含量和农作物的红边位置偏移进行相关分析,发现不同土壤重金属含量对研究区内主要农作物的影响是不同的。可以看出,在研究区内的两种主要农作物中,红薯对矿区土壤中的重金属Cr、Mn和Cd比较敏感,而南瓜则对以上三种土壤重金属具有一定的吸收和抵抗作用。该结果可以为万盛区矿区内农作物种植的选择提供理论依据。     

Carrier heating in quantum wells under optical and current injection of electron-hole pairs

Carrier heating in GaAs/AlGaAs quantum wells (QWs) under optical interband pumping in the spontaneous-emission mode has been studied. The electron temperature was determined as a function of the pumping intensity. The effect of the electric field on the photoluminescence spectrum was examined. The change in the carrier concentration with the drive current in the spontaneous- and stimulated-emission modes in InGaAsSb/InAlGaAsSb QWs was determined from electroluminescence spectra. The rise in the temperature of hot carriers, which results in the increase in the carrier concentration with the drive current, was roughly estimated.     

Growth of AlGaN epitaxial layers and AlGaN/GaN superlattices by metal-organic chemical vapor deposition

Special features of metal-organic chemical vapor deposition of AlGaN epitaxial layers and AlGaN/GaN superlattices either in an Epiquip VP-50 RP research and development reactor (for a single wafer 2 in. in diameter) or in an AIX2000HT production-scale reactor (for up to six wafers 2 in. in diameter) are stud-ied. It is found that the dependence of the aluminum content in the solid phase on the trimethylaluminum (TMA) flux in a reactor levels off; this effect hinders the growth of the layers with a high aluminum content in both types of reactors and is more pronounced in the larger reactor (AIX2000HT). Presumably, this effect is a consequence of spurious reactions in the vapor phase and depends on the partial pressure of TMA in the reactor. The aluminum content in the layers can be increased not only by reducing the total pressure in the reactor but also by increasing the total gas flow through the reactor and reducing the trimethylgallium flux. The approaches described above were used to grow layers with a mole fraction of AlN as large as 20% in the AIX2000HT production-scale reactor at a pressure of 400 mbar (this fraction was as large as 40% at 200 mbar). AlGaN layers with the entire range of composition were grown in the Epiquip VP-50 RP reactor.     

微视频在高校计算机操作性课程中的应用探究

微视频在学校各类教育中应用越来越普遍.依据微视频的教学特点,针对高校计算机操作性课程中存在的问题,本研究依据ADDIE模型和ARCS动机理论,探索构建微视频在高校计算机操作性课程中的教学应用模型,通过教学案例展示微视频在课堂应用中教与学的过程,利用微视频提高课堂教学质量.     

Lipid metabolic disorders in rats with a transplanted Pliss lymphosarcoma

Changes in biosynthesis of cholesterol and free fatty acids from 2-14C-acetate in the host liver and tumour tissue as well as concentrations of various classes of lipids in blood were determined in rats bearing the transplanted Pliss lymphosarcoma. The transplantation of the tumour stimulates cholesterol biosynthesis de novo in the liver, but produces no changes in the fatty acid synthesis. Tumour growth is accompanied by a progressive increase in the content of triglycerides and beta-lipoproteins with a parallel drop in the alpha-cholesterol level in the animal blood. The concentration of total cholesterol is of phasic character depending on the stage of tumour growth. The possible mechanisms determining such alterations in lipids metabolism are discussed.     

氧含量对VO2-x晶格特性和结构相变影响的研究

采用沉淀法制备了氧含量不同的VO2-x纳米粉．对样品进行了差式扫描量热(DSC)、X-射线衍射(XRD)和透射电子显微镜(TEM)的测试，并结合第一性原理的计算结果，具体分析了氧含量对氧化钒纳米粉的晶格特性和结构相变造成的影响：缺氧样品中形成钒填隙，富氧样品中形成氧填隙，两种缺陷分别造成晶胞体积的膨胀；缺陷带来的各向异性造成晶粒形状的改变；同时，不同缺陷态造成的能带中电子状态的改变也可能成为影响氧化钒的结构相变特性的重要因素之一．