GaAs/AlGaAs异质结的微波调制反射谱

基于搭建的微波调制反射谱测量系统(MMRS),确定了GaAs/AlGaAs异质结构中价带空穴到二维电子系统(2DES)电子基态(GS)的跃迁.微波调制反射谱与温度的依赖关系表明,随着测量温度的升高,能带带隙发生了蓝移现象;而其与磁场的依赖关系表明,随着测量磁场的增大,能带带隙则发生了红移现象;它们均与GaAs/AlGa...     

新疆预拌砂浆常用矿物掺合料的技术经济分析

研究了新疆地区较常用的粉煤灰、矿粉、锂硅粉等3种矿物掺合料替代水泥后,对预拌砂浆强度和稠度的影响,并进行了技术经济分析.     

深圳当代艺术馆与城市规划展览馆结构设计综述

深圳市当代艺术馆与城市规划展览馆为体型特别复杂的结构,包含空间倾斜面、扭曲面、旋转曲面和大悬挑结构,主楼和外表皮钢结构既相互独立又相互联系,空间关系复杂.本文介绍了项目的结构形式和结构设计技术要点,希望能为类似工程提供参考.     

浅谈商业开发与商业建筑设计

本文以万达广场的开发模式和开发思维,对商业建筑的设计及商业地产的开发进行研究,从运营角度、业态选择、商业建筑的空间组合关系、规划定位、交通策略的几个要素来阐述其对商业项目的影响。从而为商业建筑设计和商业开发提供理论参考。同时建议商业项目预留发展空间为将来商业升级增加竞争力,美化城市做出贡献。     

应急避难区对高层建筑安全疏散的影响

为提高突发火灾、恐怖袭击等紧急情况下高层建筑人员疏散的效率和安全性,减少直接通过消防楼梯进行高层建筑人员安全疏散的时间,避免因疏散中出现拥挤踩踏而造成的不必要人员伤亡,在合理选取疏散模型和设定各种疏散场景的基础上,对上海金茂大厦的部分楼层进行了高层建筑人员疏散仿真实验,并对模拟结果进行了分析和探讨。研究结果论证了在高层建筑内设置应急避难区对安全疏散缓冲的重要作用,明确了科学合理设置避难层应当注意的细节问题。     

寒冷地区农村住宅主被动太阳能结合采暖系统的技术经济性分析

本课题以北京为代表,在对寒冷地区农村住宅进行调研的基础上建立建筑模型,按建筑本体、附加保温帘、附加阳光间三种情况对模型应用Trnsys进行了逐时负荷模拟计算,对节能效果与经济性进行了分析。     

武当山明成祖敕建道宫建筑平面布局及主要建筑初探

永乐年间明成祖朱棣于武当山敕建的六座祀奉真武大帝的道宫,是明朝初期皇家道教宫观的代表作品。六座宫殿一次性规划,一次性投资,一次性建成,建筑布局规模宏大、规划严密、主次分明、大小有序,显示了皇家宫观的恢弘气度,并充分反映了当时武当山皇家道教宫观建筑的基本布局形制。该文即以这六座建成于永乐十一年至永乐十六年的道教宫观建筑为研究对象,通过现场调研以及文献研究等方法,分析明永乐年间武当山皇家敕建道宫建筑平面布局的影响因素、基本形式和主要建筑的特点。     

Optimal operation strategy development for fuel cell hybrid vehicle

An overall simulation model for fuel cell hybrid vehicle (FCHV) power train in parallel configuration using MATLAB/Simulink programming is constructed in this study. The model runs on power control strategy by using logic-threshold approach, achieved by the hybrid control unit (HCU) and fuel cell stack number. Using accelerator and decelerator pedal positions deduced from the driving schedule as the primary input, the simulation implements power flow and distribution under different vehicle operating modes. The HCU control strategy also incorporates regenerative braking and recharge for battery capacity recovery. Using the D-optimality method for experiment points selection and sequential quadratic programming (SQP) algorithm for obtaining the optimal operational parameters, three control threshold variables of HCU and optimal stack cell number are selected for hydrogen fuel economy under certain driving cycles. The proposed method provides optimized configurations of the FCHV model and the fuel cell stack, which has the capability in satisfying drive power request while satisfying vehicle driving schedule and battery state of charge (SOC) recovery with lower fuel consumption.     

疏水性中空纤维微孔膜无泡曝气试验研究

利用疏水性聚偏氟乙烯(PVDF)中空纤维膜及组件开展膜无泡曝气研究.通过检测膜组件的泡点,发现一定浸没深度下静水中膜组件的泡点高于紊流状态下的,且泡点随水流速度的增大而减小.考察水力条件和曝气压力对曝气效果的影响,并与常规曝气头曝气作比较.结果表明:将气压控制在泡点以内时,充氧能力随液体循环流量的增大、气压的升高而增强;而当气压超过泡点时,供氧初期充氧能力显著,但随曝气时间的延长增幅降低.中空纤维膜的曝气性能优于曝气头的.     

An effective four-stage smoke-detection algorithm using video images for early fire-alarm systems

This paper proposes an effective, four-stage smoke-detection algorithm using video images. In the first stage, an approximate median method is used to segment moving regions in a video frame. In the second stage, a fuzzy c-means (FCM) method is used to cluster candidate smoke regions from these moving regions. In the third phase, a parameter extraction method is used to extract a set of parameters from spatial and temporal characteristics of the candidate smoke regions; these parameters include the motion vector, surface roughness and area randomness of smoke. In the fourth stage, the parameters extracted from the third stage are used as input feature vectors to train a support vector machine (SVM) classifier, which is then used by the smoke alarm to make a decision. Experimental results show that the proposed four-stage smoke-detection algorithm outperforms conventional smoke-detection algorithms in terms of accuracy of smoke detection, providing a low false-alarm rate and high reliability in open and large spaces.