Viable：设计折射生活体验

从上个世纪九十年代中期开始，无定型的造型在设计中占据了主导。十年之后，人们的审美和设计标准发生了变化。几何原理的广泛应用使得生活物品的设计出现了“硬边”（产品的棱线和轮廓）与“精确”之风的回潮。也许是人们渴望在这个不稳定的世界中寻求稳定的元素，也许是为了用简单直白的设计来掩饰以往设计中复杂计算的造型。总之，设计师对成熟稳重的几何形式表现得情有独钟。这种席卷而来的感觉体现了一种设计的成熟，而Viable工作室的设计就是其中的代表；不仅如此，他们的设计还反映出了每个人对生活的不同理解。[编者按]     

A new iterative order reduction (IOR) method for eigensolutions of large structures

Order reduction is a computationally efficient method to estimate some lowest eigenvalues and the corresponding eigenvectors of large structural systems by reducing the order of the original model to a smaller one. But its accuracy is limited to a small range of frequencies that depends on the selection of the retained degrees of freedom. This paper proposes a new iterative order reduction (IOR) technique to obtain accurately the eigensolutions of large structural systems. The technique retains all the inertia terms associated with the removed degrees of freedom. This hence leads to the reduced mass matrix being in an iterated form and the reduced stiffness matrix constant. From these mass and stiffness matrices, the eigensolutions of the reduced system can be obtained iteratively. On convergence the reduced system reproduces the eigensolutions of the original structure. A proof of the convergence property is also presented. Applications of the method to a practical GARTEUR structure as well as a plate have demonstrated that the proposed method is comparable to the commonly used Subspace Iteration method in terms of numerical accuracy. Moreover, it has been found that the proposed method is computationally more efficient than the Subspace Iteration method. Copyright © 2003 John Wiley & Sons, Ltd.     

Silicon-to-steel bonding using rapid thermal annealing

This paper presents the rapid, low-temperature bonding between silicon and steel using the rapid thermal annealing process. Three different thin-film adhesion layer systems including silver, gold, and nickel were utilized as the intermediate bonding material to assist the eutectic Pb/Sn bonding between silicon and steel. The bonding temperature was set at 220/spl deg/C for 20 s, with a 20-s ramp-up time. Five experiments were conducted to determine the strength of the bond, including static tensile and compressive four-point bend tests, axial extension tests, tensile bending fatigue tests, and corrosion resistance tests. The test results have shown that the gold adhesion layer is the most robust, demonstrating minimal creep during fatigue tests, no delamination during the tensile or compressive four-point bend tests, and acceptable strength during the axial extension tests. Additionally, all adhesion layers have withstood four months of submersion in various high-temperature solutions and lubricants without failure. Simulations of the axial stresses and strains that developed during the four-point bend and axial extension tests were performed and showed that the presence of the silicon die provides a local reinforcement of the bond as observed in the experimental tests.     

Enhanced light output in nitride-based light-emitting diodes by roughening the mesa sidewall

In this letter, we will report on a nitride-based light emitting diode with a mesa sidewall roughening process that increases light output power. The fabricated GaN-based light-emitting diode (LED) wafers were first treated through a photoelectrochemical (PEC) process. The Ga/sub 2/O/sub 3/ layers then formed around the GaN : Si n-type mesa sidewalls and the bottoms mesa etching regions. Selective wet oxidation occurred at the mesa sidewall between the p- and the n-type GaN interface. The light output power of the PEC treated LED was seen to increase by about 82% which was caused by a reduced index reflectance of GaN-Ga/sub 2/O/sub 3/-air layers, by a rough Ga/sub 2/O/sub 3/ surface, by a microroughening of the GaN sidewall surface, and by a selective oxidation step profile of the mesa sidewall that increases the light-extraction efficiency from the mesa sidewall direction. Consequently, this wet PEC treated process is suitable for high powered nitride-based LEDs lighting applications.     

内网安全新时空--宝信网络巡警eCop典型案例分析

内网安全的重要性网络的发展给工作带来巨大便利的同时也带来了众多安全隐患,有关网络信息安全的问题日益突出。目前绝大多数的企业、学校、政府机构把安全重点放在防范来自外部的攻击,依赖于防火墙、防病毒、入侵检测等软件。尽管在所有介绍系统安全的文献中都会提及来自于内部的安全威胁,却鲜有针对内部安全隐患的防范工具与手段。2003年美国CSI/FBI提供的《计算机犯罪与安全调查报告》显示,80%以上的信息安全事件为内部人员和内外勾结所为。尤其近几年来,随着个人技术水平的提高,IP地址非法占用和盗用、非法外联现象、计算机基本信息…     

房地产企业的项目进度控制

介绍了房地产企业项目进度控制的重要性，从事前、事中、事后三个阶段探讨了工程进度的控制，以保证房地产企业的项目顺利完工，从而保证建筑物的施工质量，提高房地产企业的竞争力。     

未增塑聚氯乙烯(PVC-U)异型材配方基础

PVC-U异型材配方十分复杂,常用原料通常在10种以上。根据大连实德集团实际生产情况,这10多种原料通常以7大组分的方式进行配料和生产。文中就该配方中7大组分的分类、特点及应用情况分别进行了详细介绍。     

Design Techniques of CMOS Ultra-Wide-Band Amplifiers for Multistandard Communications

This paper presents design techniques of CMOS ultra-wide-band (UWB) amplifiers for multistandard communications. The goal of this paper is to propose a compact, simple, and robust topology for UWB low-noise amplifiers, which yet consumes a relatively low power. To achieve this goal, a common-gate amplifier topology with a local feedback is employed. The first amplifier uses a simple inductive peaking technique for bandwidth extension, while the second design utilizes a two-stage approach with an added gain control feature. Both amplifiers achieve a flat bandwidth of more than 6 GHz and a gain of higher than 10 dB with supply voltages of 1.8-2.5 V. Designs with different metal thicknesses are compared. The advantage of using thick-metal inductors in UWB applications depends on the chosen topology.     

用于实时数据传输的滑动帧方法及其实现

根据某雷达系统对测量信号的快速传输要求,提出采用滑动帧的处理方法并在FPGA中实现,克服了传统帧处理难以满足快速传输要求的不足。阐述了滑动帧结构的构造思想,详述了滑动帧结构的特点及具体功能模块的实现。根据实际应用需求构造了滑动帧结构处理器,试验和应用结果表明设计可行有效,能充分满足实时数据传输的要求。