Preparation of Zn-doped TiO2 nanotubes electrode and its application in pentachlorophenol photoelectrocatalytic degradation

Zn-doped titanium oxide （TiO2） nanotubes electrode was prepared on a titanium plate by direct anodic oxidation and immersing method in sequence. Field emission scanning electron microscopy （FESEM） showed that the Zn-doped TiO2 nanotubes were well aligned and organized into high density uniform arrays with diameter ranging from 50 to 90 nm. The length and the thickness were about 200 and 15 nm respectively. TiO2 anatase phase was identified by X-ray diffraction （XRD）. X-ray photoelectronspectroscopy （XPS） indicated that Zn ions were mainly located on the surface of TiO2 nanotubes in form of ZnO clusters. Compared with TiO2 nanotubes electrode, about 20 nm red shift in the spectrum of UV-vis absorption was observed. The degradation of pentachlorophenol （PCP） in aqueous solution under the same condition （initial concentration of PCP： 20 mg/L; concentration of Na2SO4：0.01 mol/L and pH： 7.03） was carried out using Zn-doped TiO2 nanotubes electrode and TiO2 nanotubes electrode. The degradation rates of PCP using Zn-doped TiO2 nanotubes electrode were found to be twice and 5.8 times as high as that using TiO2 nanotubes electrode by UV radiation （400 μw/cm^2） and visible light radiation （4500 μw/cm^2）, respectively. 73.5% of PCP was removed using Zn-doped TiO2 nanotubes electrode against 45.5% removed using TiO2 nanotubes electrode in 120 min under UV radiation. While under visible light radiation, the degradation efficiency of PCP was 18.4% using Zn-doped TiO2 nanotubes electrode against 3.2% using TiO2 nanotubes electrode in 120 min. The optimum concentration of Zn doping was found to be 0.909%. The PCP degradation efficiencies of the 10 repeated experiments by Zn-doped TiO2 nanotubes electrode were rather stable with the deviation within 3.0%.     

基于ABAQUS强度折减法分析库水位下降对边坡稳定性影响

三峡水库自运行以来,库水下降成为滑坡复活的一个诱因.本文根据库区水位调度方案,利用ABAQUS软件模拟库水位在175～145m的下降过程,考虑饱和-非饱和渗流场与应力场耦合理论效应,并采用强度折减法分析库水下降对树坪滑坡稳定性的影响.分析结果表明:三峡水库以0.21m/d的速度由175m降至145m时,树坪滑坡前缘会产生一定的变形,滑坡后缘和中部,基本上未产生变形,目前树坪滑坡处于较稳定状态,但在库水反复变动及降雨作用下,可能会面临失稳的危险.其成果将为库区滑坡治理提供一定的理论依据.     

用刚塑性有限元法分析超塑性反挤压成形

本文用刚塑性有限元法分析超塑性反挤压成形的流动规律，定量地分析了影响超塑性变形抗力的因素，预测了反挤压变形抗力和变形区的应力应变分布规律，为预测超塑性材料的反挤压变形抗力、速度场及等效应变速率提供了计算机模拟实验的通用程序。     

Simulation of maximum light use efficiency for some typical vegetation types in China

MAXIMUM LIGHT USE EFFICIENCY(ΕMAX)IS THE USE RATE OF PHOTOSYNTHETICALLY ACTIVE RADIATION BY VEGETATION IN AN IDEAL CONDITION WITHOUT ANY CONSTRAINTS.IT IS A PHYSIOLOGICAL ATTRIBUTE OF PLANT ITSELF.THE VALUE OFΕMAX IS DIFFERENT FOR DIFFERENT VEGETATION TYPES[1―5].IT IS A KEY PARAMETER FOR THE ESTIMATION OF NET PRIMARY PRODUCTIVITY(NPP)DRIVEN WITH REMOTE SENSING DATA.THERE…     

电厂远程专家分析平台的建立

提出了建立电厂远程专家分析平台的整体方案．合理构建了电厂远程实时运行数据库平台，基于此数据库平台，进行专业应用软件的开发．介绍了远程实时监视、远程经济性分析、远程仿真、远程故障诊断等专业软件的开发思路.     

计算机绘制曲线、曲面的数学方法

本文讲述目前在CAG和CAD设计过程中所遇到的曲线和曲面的数学模型,给出主要类型的曲线和曲面确定的几何条件、方程及其简单的几何性质。为解决三维图形的计算机显示问题,给出三维图形在计算机上显示的数学公式。     

氮在饱和土壤层中迁移转化特征研究

通过室内土柱实验，研究了氮在包气带不同土质层中饱水条件下迁移转化的特征；建立了一维饱和土壤层中氮迁移的预测模型。研究结果表明：氮对地下水的污染因子是硝酸根；土质是影响土壤氮迁移的重要因素之一。在迁移转化环境条件相同的情况下，随着土壤颗粒中粘粒含量的增加，土层的净化容量增加，其中土层的反硝化反应速率的增加是硝酸根去除的决定性因素。     

地理信息系统发展动态及在水资源管理方面的应用

地理信息系统（ＧｅｏｇｒａｐｆｏｉｃＩｎｆｏｒｍａｔｉｏｎＳｙｓｔｅｍ，ＧＩＳ）具有高效的空间数据管理和灵活的空间数据综合分析能力，在国外得到了广泛应用，国内也正在研究和应用。本文在搜集和阅读大量国内外文献的基础上，综述了ＧＩＳ的发展动态及趋势，着重介绍了国内外ＧＩＳ在水资源管理方面的应用概况，并对ＧＩＳ在水资源管理中的应用作了展望。     

A theoretical exploration of the origin and early evolution of a pandemic

A virus that can cause a global pandemic must be highly adaptive to human conditions.Such adaptation is not likely to have emerged suddenly but,instead,may have...     

基于Xsim平台的防空导弹武器系统仿真平台设计

以系统仿真技术在防空导弹武器系统的方案论证、优化设计、飞行试验预测、作战效能评估等方面中的应用为背景,提出了一种基于Xsim平台的防空导弹武器系统仿真平台设计方法。论述了该平台的总体架构设计、模型设计以及仿真流程设计,给出了设计思路。完成了某防空导弹武器系统仿真平台的应用开发,实践表明该平台可以较好的开展防空导弹武器系统作战过程仿真,可用于支撑防空武器装备各阶段的仿真工作,提升复杂战场环境下防空武器装备研发论证及设计能力。