美国萨维奇拉皮兹坝的拆除

美国萨维奇拉皮兹（Savage Rapids）坝自1921年动工兴建以来,鱼类如何过坝一直是专家关注的焦点。经研究,最终决定于2006年10月开始拆除这座有88 a历史的大坝。该项工程于2006年10月开工,并于2009年11月完工,随后新建了灌溉分流设施,结果不仅恢复了溯河鱼类通道,而且促进了当地经济发展。     

买45nm处理器正当时!AMD3A平台处理器导购指南

俗话讲．“一分钱一分货”．在处理器市场上向来是荷包里多少钱．就能买到什么级别的处理器。但话又说回来，同样的价格你也可以有很大的选择余地，比方说同为入门级双核处理器．你会选择以前的老速龙64X2处理器．还是新的速龙Ⅱ处理器？其中的差别你知道在哪里吗？     

英国泰晤士河上的皇家电站

2012年10月，英国泰晤士河上的一座小型水电站竣工发电，它将为英国女王陛下的皇家官邸温莎城堡供电。对修建这座具有特殊功能的小型发电站的提出背景、别致的设计方案，以及设计方案的研制过程和施工技术等，均作了较为详细的描述。     

混凝土裂缝预防与科学处理

混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。     

组织如何保持已取得的质量优势

直到现在，丰田汽车公司的质量体系还被视为典范。但最近，这家公司正在因为质量和安全问题接受调查。丰田所遇到的困境表明，要做到最好并保持最好有多么难。     

Structural and opto-electrical properties of pyrolized ZnO-CdO crystalline thin films

A series of ZnO-CdO thin films of different molar ratios of Zn and Cd have been deposited on glass substrate at substrate temperature ~ 360 ℃ by the spray pyrolysis technique at an ambient atmosphere. X-ray diffraction (XRD) studies confirmed the polycrystalline nature of the film and modulated crystal structures of wurtzite (ZnO) and cubic (CdO) are formed. The evaluated lattice parameters, and crystallite size are consistent with literature. Dislocation density and strain increased in the film as the grain sizes of ZnO and CdO are decreased. The band gap energy varies from 3.20 to 2.21 eV depending on the Zn/Cd ratios in the film. An incident photon intensity dependent I-V study confirmed that the films are highly photosensitive. Current increased with the increase of the intensity of the light beam. The optical conductivity and the optical constants, such as extinction coefficient, refractive index and complex dielectric constants are evaluated from transmittance and reflectance spectra of the films and these parameters are found to be sensitive to photon energy and displayed intermediate optical properties between ZnO and CdO, making it preferable for applications as the buffer and window layers in solar cells.     

The impact of gate misalignment on the analog performance of a dual-material double gate junctionless transistor

The analog performance of gate misaligned dual material double gate junctionless transistor is demonstrated for the first time. The cases considered are where misalignment occurs towards source side and towards drain side. The analog performance parameters analyzed are: transconductance, output conductance, intrinsic gain and cut-off frequency. These figures of merits (FOMs) are compared with a dual material double gate inversion mode transistor under same gate misalignment condition. The impacts of different length of control gate (L₁) for a given gate length (L) are also studied and the optimum lengths L₁ under misalignment condition to have better analog FOMs and high tolerance to misalignment are presented.     

Concerning the maximum frequency limits of Gunn operators

The length of the transit region of a Gunn diode determines the natural frequency at which it operates in fundamental mode－the shorter the device, the higher the frequency of operation. The long-held view on Gunn diode design is that for a functioning device the minimum length of the transit region is about 1.5 μm, limiting the devices to fundamental mode operation at frequencies of roughly 60 GHz. The authors posit that this theoretical restriction is a consequence of limits of the hydrodynamic models by which it was determined. Study of these devices by more advanced Monte Carlo techniques, which simulate the ballistic transport and electron-phonon interactions that govern device behaviour, offers a new lower bound of 0.5 μm, which is already being approached by the experimental evidence shown in planar and vertical devices exhibiting Gunn operation at 0.6 μm and 0.7 μm. It is shown that the limits for Gunn domain operation are determined by the device length required for the transferred electron effect to occur(approximately 0.15 μm, which as demonstrated is largely field independent) and the fundamental size of the domain(approximately 0.3 μm). At this new length, operation in fundamental mode at much higher frequencies becomes possible－the Monte Carlo model used predicts power output at frequencies over 300 GHz.     

试论智能电网的信息安全技术

在建设智能电网的过程中应该对智能电网涉及的信息安全问题进行充分考虑。本文主要对智能电网信息安全技术内容进行了简要的分析,并对如何建立智能电网主动信息安全防御体系的技术构建进行了相关探讨,希望可以为智能电网信息安全提供一些借鉴。     

项目管理成熟度在建设工程领域的研究综述

项目管理成熟度模型在IT行业取得的巨大成功使之很快被应用到了20多个领域,建设工程领域就是其中之一。国内建设项目管理成熟度的研究已历经10余年,各种研究混杂交错,需要得到比较系统的梳理。从项目管理成熟度的发展历程和研究现状出发,从基础理论和应用障碍研究以及建设项目管理成熟度模型两个方面对其在我国建设工程领域的研究情况进行了剖析。并分别从建设细分领域和参建方的不同视角进行了成熟度研究现状的综述,指出了建设领域成熟度研究对非过程因素的忽视。期望对建设工程领域的后续成熟度研究有所启迪。