一种新型自摆消防炮控制系统的设计

针对目前常用的水力自摆式消防炮通用性差的问题,介绍了一种新型的自摆式消防炮控制系统的设计。该系统具有无线遥控和面板电控2种控制方式,能够进行大范围自动扫射灭火操作;采用单片机构成微处理单元,对控制信号和限位开关信号进行处理,并做出相应的控制动作;设计了无线遥控模块,采用3路集成驱动器件L298实现消防炮的运动驱动。工程实践结果表明,该系统工作可靠,使用简单,应用场合广泛。     

一种基于关系图的Web应用测试生成方法

Web应用的迅猛发展及其自身的复杂特性给其测试带来了一定的难度,使得传统的测试方法已不能满足需求,迫切需要新的Web测试方法和技术.定义了Web应用模式并构造其关系图以对Web应用进行建模.关系图用来建立产生路径表达式的路径生成图,继而提出一种测试路径生成方法.若提供输入值,则测试路径可以很容易地构造测试用例.为了说明问题,给出了一个简单Web登录系统作为案例.此外,根据"分而治之"的原理,当被测Web应用过于复杂时,给出了一种路径生成策略.该策略使得Web应用简单而易控制,在某种程度上限制了状态空间的爆炸.最后,从理论上阐明了本文给出方法和规则的通用性及正确性.     

社会网络用户心理健康自动评估研究综述

心理健康问题正迅速成为世界范围内最严重和最普遍的公共卫生问题之一.社会网络的兴起与普及带来大量与社会网络用户心理状态相关的数据.近年来,利用社会网络数据自动评估检测用户心理健康的研究吸引着越来越多的学者,取得了不少成果,但未见对这些成果进行总结分析的工作.该文对社会网络用户心理健康自动评估的相关文献进行评述:在现有文献...     

FRP与混凝土组合结构研究综述

提出一种在塑性铰区域采用高延性纤维增强水泥基复合材料(ECC)替代混凝土来改善FRP筋-钢筋增强混凝土柱抗震性能的新方法。对FRP筋-钢筋增强ECC-混凝土构件进行了低周往复荷载试验,系统地考察了基体材料、筋材种类、轴压比对构件破坏模态、裂缝模式、承载力、残余变形、延性和耗能能力的影响。结果表明,将ECC替代塑性铰区域混凝土能够有效避免FRP筋的受压屈曲,进而显著提升组合柱的抗震性能。与钢筋增强ECC-混凝土组合柱相比,复合筋增强ECC-混凝土组合柱的残余变形明显更小,且屈服后的刚度更高。随着轴压比的增大,构件极限强度升高但变形能力降低。通过有限元参数分析可知,组合柱的承载力和变形能力均随着ECC抗压强度及总配筋率的增大而增大;在总配筋率不变的情况下,FRP筋占比越高,构件的延性越好。     

基于神经网络的电力系统暂态稳定分布式自适应控制

针对电力系统中普遍存在的系统非线性和参数不确定性等问题,提出一种基于径向基函数神经网络(RBFNN)的分布式自适应控制器,以提高多机电力系统的暂态稳定性.利用基于RBFNN的方法对系统中的未知非线性项和外部扰动进行补偿,设计相应的自适应参数估计方法,逼近未知非线性项的理想权值矩阵.该策略基于多智能体框架,分布式控制器通...     

Efficient numerical integration of an elastic–plastic damage law within a mixed velocity–pressure formulation

This study focuses on numerical integration of constitutive laws in numerical modeling of cold materials processing that involves large plastic strain together with ductile damage. A mixed velocity–pressure formulation is used to handle the incompressibility of plastic deformation. A Lemaitre damage model where dissipative phenomena are coupled is considered. Numerical aspects of the constitutive equations are addressed in detail. Three integration algorithms with different levels of coupling of damage with elastic–plastic behavior are presented and discussed in terms of accuracy and computational cost. The implicit gradient formulation with a non-local damage variable is used to regularize the localization phenomenon and thus to ensure the objectivity of numerical results for damage prediction problems. A tensile test on a plane plate specimen, where damage and plastic strain tend to localize in well-known shear bands, successfully shows both the objectivity and effectiveness of the developed approach.     

The 2012 free and open source GIS software map – A guide to facilitate research,development, and adoption

Over the last decade an increasing number of free and open source software projects have been founded that concentrate on developing several types of software for geographic data collection, storage, analysis and visualization. We first identify the drivers of such software projects and identify different types of geographic information software, e.g. desktop GIS, remote sensing software, server GIS etc. We then list the major projects for each software category. Afterwards we discuss the points that should be considered if free and open source software is to be selected for use in business and research, such as software functionality, license types and their restrictions, developer and user community characteristics, etc. Finally possible future developments are addressed.     

基于微分进化算法的发电商机组出力综合性优化策略

提出了一种新的基于改进微分进化算法的电力市场机组出力综合性优化策略。根据机组出力与市场电价之间的协调联动关系,以交易日售电总利润最大化为目标,综合考虑机组运行成本、阀点效应、环境保护成本、实际报价风险系数,构建了交易日机组分时段出力优化模型,由此得出机组的综合性发电优化方案。设计了一种加入随机扰动因子进行变异以克服收敛早熟的微分进化算法对所构建的具有非线性、非凸特性的动态规划模型进行快速准确地求解。算例的仿真分析结果验证了该方法的可行性和优越性。     

Organic–Inorganic Nanohybrids as Novel Thermoelectric Materials: Hybrids of Polyaniline and Bismuth(III) Telluride Nanoparticles

Thermoelectric materials have received much attention recently from the viewpoint of global environmental issues and effective utilization of energy resources. Especially those effective at relatively low temperature, such as below 100°C, which are usually abandoned without use, have become noteworthy recently. From this point of view, organic thermoelectric materials are most attractive, because they could be prepared at low cost and applied in various locations due to their flexibility. We have investigated the thermoelectric properties of organic conducting polymers such as polyaniline, polypyrrole, and polyphenylenevinylene, and succeeded in increasing the thermoelectric performance by selecting dopants, stretching conducting films, etc. Recently we have focused on new systems of organic–inorganic hybrid thermoelectric materials. Herein we present the preparation of a novel system of hybrids of polyaniline and bismuth(III) telluride nanoparticles, starting from bismuth(III) chloride and tetrachlorotellurium by using polyvinylpyrrolidone as a protecting reagent, as well as their thermoelectric properties. The hybrids prepared by this particular method showed much higher thermoelectric performance than the starting organic conducting polymer.     

LED在隧道照明工程中的应用研究

LED作为新型的光源,具有许多优越的性能,尤其是良好的节能性,正在快速的应用到隧道照明之中。文章详细介绍了LED发展的国内外概况,LED在隧道照明中的需求以及LED的基本分类和光源的特性,并对隧道内常用照明光源的性能进行了比较;阐述了隧道照明的设计规范、准则和设计要求,并通过举例展示LED在实际工程中的应用效果和节能特性;针对现阶段我国LED发展情况,分析了LED存在的一些问题和解决的方法,最后指出LED未来的发展方向：高功率、低成本、标准化、智能化和多元化。