气-固流化床中TiO2光催化剂的载体选择与催化动力学研究

在自制的流化床光催化反应装置中进行了TiO2光催化剂的载体选择与催化动力学研究,考察了石英砂、陶瓷球、粗孔硅胶和活性炭颗粒四种栽体的负载型TiO2催化剂光催化降解甲苯的性能及TiO2／粗孔硅胶的催化反应动力学。结果表明,粗孔硅胶是最适用于气固流化床光催化反应体系的载体;TiO2／粗孔硅胶光催化氧化甲苯反应符合Langmuir—Hinshelwood动力学模型,反应速率常数k为2．06262mg／（m^3·min）,吸附平衡常数K为0．03683m^3／mg。     

半导体光催化氧化反应降解废水中有机污染物的研究进展

介绍了一种降解废水中有机污染物的高效氧化方法（AOP）－半导体光催化氧化法及其作用原理与反应机理；总结了近年来提高半导体光催化效率的方法：半导体光催化剂的改性、光催化剂的固定化、加电子接受剂或空穴接受剂，特别是采用AOP与生化降解法相结合的方法，使废水的处理更经济、有效。综述了近两年该技术在处理废水中有机污染物方面的应用。     

光催化技术在降解无机含氮污染物方面的应用

光催化技术是一种新兴的高效节能绿色环保技术，本文在介绍半导体光催化反应机理的基础上、对NOx、NO2^-污染物光催化降解的现状、提高半导体光催化剂活性的途径、光催化技术发展中存在问题等进行了综述，重点介绍了半导体光催化技术在降解无机含氮污染物方面的应用。     

水处理中光催化氧化剂的研究进展

该文介绍了光催化氧化技术的原理,从传统光催化剂的改性、新型光催化剂开发等角度阐述了光催化降解水中污染物的研究进展,分析了提高光催化反应效果的途径和今后光催化氧化剂的研发方向.     

光催化氧化降解水中有机污染物的研究进展

光催化氧化能降解直至矿化多种有机污染物，是一种极具应用前景的水处理技术．对光催化氧化在国内外的研究和应用现状进行了介绍，包括均相和非均相光催化氧化机理、影响因素、实际应用、反应动力学、反应器、催化剂等，并讨论光催化氧化目前存在的问题及今后研究的发展方向．     

光催化TiO2薄膜研究进展及其影响因素

提高光催化剂的光催化活性是多相光催化剂能否工业化应用的关键，文章介绍了半导体多相光催化材料的理论及应用的发展现状，探讨了玻璃表面TiO2薄膜光催化性能的影响因素及提高其光催化降解效率的途径。     

掺铜方法对二氧化钛光催化氧化还原性能的影响

采用浸渍法、水解沉淀法、机械混合法制备了铜掺杂的TiO2光催化剂.利用XRD,XPS,TPR等手段对不同样品进行了表征,以乙酸水溶液的光催化氧化降解及二氧化碳光催化还原为反应探针,对3种催化剂光催化活性进行了评价.结果表明,不同方法掺铜影响催化剂表面性质如吸附氧、元素价态及分布,进而影响光催化性能.吸附氧的性能以及存在合适比例的氧化还原对Cu+/Cu2+导致浸渍法制备的掺铜TiO2光催化剂具有最好的光催化活性.     

纳米TiO2光催化氧化甘氨酸及其氧化机理的研究

研究了纳米TiO2对甘氨酸的光催化氧化性能及其氧化机理．结果表明，在实验浓度范围内，甘氨酸的光催化氧化符合准一级动力学反应．纳米TiO2的用量和溶液pH值都影响光催化反应．外加无机氧化物，能有效地捕获光致电子，增加溶液中羟基自由基的浓度，提高甘氨酸的光催化氧化能力．     

流化光催化反应器降解水中有机污染物

采用溶胶一凝胶结合CO2超临界干燥方法与浸渍法制得了颗粒型与薄膜型TiO2光催化剂，选择苯酚和苯胺为炼厂废水难降解污染物的模型物，通过流化光催化反应器与固定式光催化反应器考察了反应条件对苯酚、苯胺降解的影响．实验结果表明，溶胶—凝胶结合CO2超临界干燥方法有利于制很大比表面、大孔容、高活性TiO2催化剂，流化光催化反应器对苯酚、苯胺的降解效果要优于浆式反应器与固定式反应器，光催化方法适宜于对低浓度污染物废水的深度处理，优化反应条件有利于提高光催化效率．     

光催化技术研究进展

光催化技术是一种新兴的高效节能现代污水处理技术,从半导体光催化方法、反应机理、各类污染物光催化降解的现状、提高半导体光催化剂活性的途径、光催化技术发展中存在问题等方面分别论述了半导体光催化技术现状及发展趋势.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。