高速响应的非线性光学玻璃

日本玻璃中央研究所开发世界最高水平的非线性光学玻璃,使用这种玻璃试制成超高速光开关。这种玻璃是半导体微粒玻璃的一种,在通常硼硅酸玻璃中掺半导体的氧化铜微粒的玻璃,若光照射玻璃,会使半导体微粒吸收光,并在非常小的空间中形成电子和空穴,其结果,提高了玻璃的本征非线性光学效果。虽然半导体微粒玻璃非线性效应较强,但有吸收较大和响应速度慢的问题。     

中波红外玻璃的研究

中波红外玻璃综合了优良的透红外性能、大尺寸制备特性和低成本等特点,是很多重要军用系统的关键窗口材料之—.中波红外玻璃材料主要包括氟化物玻璃、铝酸钙玻璃、锗酸盐玻璃、镓酸盐玻璃、碲酸盐玻璃和重金属氟氧化物玻璃等.中波红外玻璃材料目前的基本性能表明了其存在的问题.指出了当前中波红外玻璃的国内外研究现状及其发展趋势.     

玻璃激光焊接气孔控制研究

为了获得成形良好、气孔少的玻璃焊接焊缝,采用在中间层添加对激光波长不透明玻璃料的方法,对玻璃与玻璃激光焊接中出现的气孔问题进行了研究.以半导体激光作为热源,搭建了用于玻璃与玻璃激光焊接的成套焊接设备,对玻璃与玻璃激光焊接工艺进行了实验研究.通过分析气孔分布特征,统计焊缝气孔率,测量气孔尺寸,对比焊缝正、反面形貌差异,研...     

国外照明玻璃的最新进展

照明玻璃的多样化和玻璃品种的多样化是联系在一起的,照明玻璃的发展史也就是照明灯泡的发展史,要开发新光源也就要开发具有新特性的玻璃。但最近的发展动向不只是开发具有新特性的玻璃,更重要的是强调节能和节省原材料。本文将介绍几种照明玻璃的最新进展:即环形荧光灯用低铅玻璃;汽车前灯用硼硅玻璃;卤素灯用铝硅酸玻璃和杀菌灯用硼硅玻璃。     

可自适应位移变化的玻璃厚度激光三角测量方法

传统的激光三角法测量玻璃厚度时,玻璃与测头的相对位置需保持固定,每当玻璃位置移动时,均需重新标定才能进行准确测量。针对这一问题,提出可自适应位移变化的玻璃厚度激光三角测量方法,玻璃在不同位置时均可以直接对玻璃厚度进行测量。首先分析当玻璃位于基准位置时,其前、后表面反射光的成像光斑间距与玻璃厚度之间的关系;其次分析当玻璃位移变化时,成像光斑间距与玻璃前表面位置、玻璃厚度之间的关系,建立数学模型,并相应地提出修正算法来消除玻璃位移变化对厚度测量的影响;最后设计了基于激光二极管-互补金属氧化物半导体(LD-CMOS)的激光三角测量系统,并采用多块已知厚度的玻璃样本进行标定和测量实验。实验结果表明,当玻璃位置在1~4.5 mm的范围内变动时,不同位置处玻璃厚度测量的绝对误差小于0.010 mm,并且相对误差均在0.5%以内。该方法实现了玻璃在不同位置时对玻璃厚度的高精度测量,无需重复标定,具有很好的实用性、灵活性和通用性。     

节能型低比辐射率玻璃

采用低比辐射率玻璃（Ｌｏｗ－Ｅ玻璃）的双层玻璃有两种类型,一种是适合于寒冷地区用的;另一种是适合于比较温暖的地区用的。对这种玻璃的热解结果,认为它完全枳工替单板玻璃。如果把适合于温暖地区用的Ｌｏｗ－Ｅ玻璃装设在住宅的出口处,可以把冷气设备的负荷量降低约２５％,冬季,窗玻璃附近的冷空气沿着玻璃流失（冷气流）的现象和了,与不采用Ｌｏｗ－Ｅ玻璃的双层玻璃相比较,采用这种玻璃会使整个居家都变暖。     

建筑用玻璃/不锈钢、玻璃/钛合金激光焊接机理研究

开展了玻璃/不锈钢和玻璃/钛合金的激光焊接试验研究,重点分析了焊缝的断口形貌、截面形貌及焊缝处物相的差异。结果表明,玻璃/不锈钢、玻璃/钛合金焊接的机理类似,焊缝中玻璃与金属形成的镶嵌结构及分布在界面处的粘附物是两者能连接的主要原因;玻璃与钛合金的线膨胀系数差异较小是玻璃/钛合金焊接件拉断力高的主要原因;激光作用下玻璃与钛合金形成化学结合,生成化合物Ti5Si3,而玻璃与不锈钢主要为机械混合。     

彩色显像管玻璃用原料及选用原则

彩色显像管玻璃的玻璃成份是决定玻璃物理化学性质的主要因素。实际上，人们往往以改变玻璃的成份来调整和控制玻璃性质。玻璃成份在一定程度上对玻璃结构亦会产生决定性的影响，因此，玻璃成份是玻璃工艺的重要研究对象之一。     

中红外玻璃的研究现状及发展

随着红外技术的不断发展,红外玻璃面临着巨大的机遇与挑战。简要介绍了近年来国内外主要用于3～5μm的氟化物玻璃、铝钙玻璃、锗酸盐玻璃、镓酸盐玻璃等的相关性能及发展现状,并探讨了中红外玻璃的发展趋势。     

多种玻璃材料的电波穿透损耗测量

针对不同玻璃材料的穿透损耗测试数据匮乏以及测试方法简单的问题,采用屏蔽室开窗法对O.831 GHz~2.661 GHz频段上无线通信常用频点电磁波通过不同种类玻璃材料的穿透损耗进行测量。测量材料包括钢化玻璃、茶色玻璃、夹钢丝玻璃和单向透明玻璃等。电波在2.391 GHz上穿透单向透明玻璃时测得最大穿透损耗26.61 dB。测试结果表明,对于不同玻璃材料的电波穿透损耗,玻璃色彩不是影响穿透损耗的本质原因,玻璃中含有的其他金属物质如钢丝及金属镀膜等对穿透损耗影响较大。     

GEMNET: a generalized, shuffle-exchange-based, regular, scalable,modular, multihop, WDM lightwave network

GEMNET is a generalization of shuffle-exchange networks and it can represent a family of network structures (including ShuffleNet and de Bruijn graph) for an arbitrary number of nodes. GEMNET employs a regular interconnection graph with highly desirable properties such as small nodal degree, simple routing, small diameter, and growth capability (viz. scalability). GEMNET can serve as a logical (virtual), packet-switched, multihop topology which can be employed for constructing the next generation of lightwave networks using wavelength-division multiplexing (WDM). Various properties of GEMNET are studied     

Thermodynamics of copper matte converting: Part III. Steady-state volatilization of Au,Ag, Pb,Zn, Ni,Se, Te,Bi, Sb,and As from slag,matte, and metallic copper

A comprehensive compilation of various thermodynamic data required for a complete analysis of copper matte converting reactions is presented. The data comprise estimated free energies of formation for such gases as SeO, SeS, TeO, TeS, BiO, BiS, SbO, SbS, AsO, and AsS, as well as activity coefficients in dilute copper alloys and vapor pressures of various elements and compounds. The volatilization of minor elements in steady-state reactors comprising gas and several condensed phases is mathematically formulated, and a parameter which governs the volatilization in such reactors is defined and named volatilization constant. The vapor pressures of various volatile species are calculated thermodynamically for the Noranda Process reactor by assuming equilibrium conditions. The volatilization constants of various minor elements are expressed explicitly as functions of oxygen and sulfur activities. Formerly Associate Professor, Department of Metallurgical Engineering, University of Utah, Salt Lake City, UT     

Bits, symbols, bauds, and bandwidth

The use of clear, concise, and unambiguous language in telecommunications engineering is vital to communicate a desired meaning and understanding. Terminology should be based on rigorous engineering principles and traceable to well known and dependable sources. This article deals with four everyday terms commonly encountered in the popular semi-technical press as well as in serious engineering periodicals. The misuse of these and other terms can lead to low-balled cost proposals, court litigation, and patent infringement cases. Imagine how an engineering student can be confused when she/he typically encounters bandwidth measured in bits per second     

Novel planar, square-shaped, dielectric-waveguide, single-, and dual-mode filters

This paper presents a novel concept of a square-shaped dielectric-waveguide resonator, which can easily realize a dielectric-waveguide cross-coupled filter or a dielectric-waveguide dual-mode filter, using the conventional printed circuit board (PCB) process. This planar dielectric-waveguide resonator has a higher Q value than a microstrip resonator. The physical mechanisms of both single- and dual-mode filters are elucidated. Some new coupling structures are developed for undergoing the PCB process. Filter design procedures are detailed. Design curves for the coupling coefficients of internal- and external-coupling structures are determined by full-wave finite-element-method electromagnetic calculations. Measurement results are highly consistent with theory for all trial filters. This study offers an effective means of producing low-cost high-performance planar circuit filters.     

PBX技术.市态.营销.选购

本文介绍了ＰＢＸ交换机的技术及市场需求态势。并提出ＰＢＸ产品的营销要素及其用户在选购时应遵循的原则。     

Dilemmas,uncertainty, risks,and board performance

This paper traces the origins of the words risk, uncertainty, governance and development and argues that a deeper understanding of each allows more effective decision taking in the boardroom. It argues that the role of the board of directors is to balance and rebalance continuously their irresolvable dilemma — ‘how do we drive our enterprise forward while keeping it under prudent control?’ It argues that it is the board’s role to focus on uncertainty, rather than risk, and this requires a different set of intellectual skills from board members to be able to cope with monitoring a range of diverse scenarios. This is crucial for a board to develop stronger ways of both leading their organisation and of ensuring the connectedness of the learning within and between the board and the operational unit’s risk taking. It advocates that to achieve this a board must develop new ways of learning — especially of thinking strategically and becoming more sensitised to the dynamics of their changing external environments. This will take them well beyond the comforts of their specialist managerial disciplines and into the true world of directing. The paper demonstrates the importance of continuous learning in reducing organisational uncertainty and risk. It uses the ‘Learning Board’ process and model as the central processor of both strategic and operational learning to create an annual rhythm for the board’s year.