超临界制备Ti02光催化剂及其活性研究

以钛酸丁脂为钛源，用溶胶-凝胶法制得催化剂前驱体，用超临界干燥法处理获得大孔及高比表面积的TiO2超细颗粒；该样品在苯酚光催化降解反应中显示出优良的催化性能，其催化活性显著优于由直接干燥法处理获得的TiO2颗粒，而且催化剂具有良好的热稳定性，即使经过973K的高温焙烧，仍能保持良好的催化活性．结合催化剂的系列表征，包括XRD、TEM、氮气吸附-脱附等温线、XPS等，初步讨论了超临界干燥法对改善TiO2光催化活性的结构因素．     

迷宫流鼓泡光催化反应器结构对甲基橙降解性能的影响

设计了新型迷宫式鼓泡光催化反应器(LBPR),以30～40目活性碳为载体,采用溶胶-凝胶法制备了负载型TiO2薄膜颗粒光催化剂,对含甲基橙废水进行光催化降解.考察了反应器内折流板数量与出水液面高度等结构参数及液速对有机物降解性能的影响.结果表明:当折流板为12块,液面高度为4 cm时,在液量0.011 1 m3/h、催化剂4.8 g/L的完全流化的操作条件下反应1.5 h,降解率达到100%.此外还考察了催化剂带出量及其在反应器中的停留时间随液体流量以及折流板数的变化关系.     

超临界制备TiO2光催化剂及其活性研究

以钛酸丁脂为钛源，用溶胶-凝胶法制得催化剂前驱体，用超临界干燥法处理获得大孔及高比表面积的TiO2超细颗粒；该样品在苯酚光催化降解反应中显示出优良的催化性能，其催化活性显著优于由直接干燥法处理获得的TiO2颗粒，而且催化剂具有良好的热稳定性，即使经过973K的高温焙烧，仍能保持良好的催化活性．结合催化剂的系列表征，包括XRD、TEM、氮气吸附-脱附等温线、XPS等，初步讨论了超临界干燥法对改善TiO2光催化活性的结构因素．     

载银TiO2及AgCl光催化降解有机污染物的研究现状

TiO2是一种优良的光催化材料，在TiO2表面负载金属银能显著提高其光催化活性，目前在TiO2表面沉积银的方法主要有溶胶-凝胶法、光化学沉积法、Ag2CO3法、银镜反应法、光催化还原金属离子法等。在对掺银改善纳米二氧化钛光催化性能的研究基础上，人们发现了卤化银作为光催化剂的光催性能。通过比较发现，AgCl在光催化降解水中有机污染物的过程中应该有与TiO2相似的反应机理。     

TiO_2纳米粒子的制备及光催化性能研究

文章以三氯化钛、氨水为原料,琼脂为反应介质,通过凝胶网格法制备锐钛矿型TiO2纳米粒子,采用XRD、SEM对产品进行了表征;对TiO2光催化氧化处理苯酚类废水溶液进行了研究,讨论了催化剂用量、苯酚质量浓度、脱色时间等因素对降解率的影响。实验表明,TiO2具有良好的光催化活性,可以有效地对苯酚类废水进行降解,纳米TiO2的光催化活性明显高于普通氧化钛。     

POMs/TiO2复合催化剂光催化降解染料废水的研究

采用溶胶-凝胶方法表面修饰TiO2制备了几种POMs/TiO2复合光催化剂,考察了催化剂在紫外光照射下对模拟染料废水(茜素红溶液)的光催化降解行为.结果表明:POMs/TiO2复合催化剂较纯TiO2光催化降解茜素红活性明显提高,其中复合催化剂Cr3OSiW12/TiO2光催化降解模拟染料废水(茜素红溶液)效果最佳.反应最佳条件:催化剂为Cr3OSiW12/TiO2,多酸质量分数为0.5%,催化剂用量为15 mg,茜素红溶液浓度为0.1mmol/L.茜素红降解质量分数可达74.6%.     

醋酸对玻璃负载TiO2膜光催化的影响

以钛酸丁酯、乙醇、硝酸为原料,采用溶胶-凝胶法制备玻璃负载型TiO2膜,用醋酸浸渍对其进行表面修饰以增加其光催化活性,用直接耐晒蓝染料模拟废水中难降解的有机污染物.研究结果表明,醋酸浸渍可以增加坡璃负载型TiO2膜光催化活性,当采用0 25mol/L醋酸浸渍玻璃负载型TiO2膜1h,TiO2膜120min内降解率由13 8%提高到42%.     

TiO2的微波辐射Sol-Gel法制备及其光催化性能

采用微波辐射Sol-Gel法在石英砂表面制备负载型TiO2光催化剂，考察不同加热方式。微波功率以及微波加热温度对溶胶质量的影响，微波加热反应制备的溶胶粒子平均粒径小于常规加热反应制备得到的溶胶粒子，微波加热反应适宜条件是微波功率600W，反应温度为90℃、以苯酚为光催化降解研究对象，考察了两种方式制备的负载型TiO2光催化剂的催化性能，实验结果表明微波辐射Sol-Gel法制备的负载型TiO2光催化剂光催化性能也优于常规Sol-Gel法制备的负载型TiO2光催化剂。     

半导体光催化氧化技术的研究进展

作为一种高级氧化工艺，半导体光催化氧化技术能有效降解多种对环境有害的污染物，使污染物矿化为CO2、H2O及其他无机小分子物质．在诸多半导体光催化剂中，TiO2由于无毒、催化活性高、氧化能力强、稳定性好、成本低，成为最常用、也是最具潜力的一种光催化剂．阐述了TiO2光催化氧化的反应机理，介绍了决定TiO2光催化性能的因素及提高其活性的方法，总结了光催化反应器的发展及影响光催化反应效率的因素，并展望了半导体光催化氧化技术的前景，指出了今后的研究方向．     

纳米TiO2薄膜的制备及光催化活性研究

用溶胶一凝胶法在玻璃基片上制备了均匀透明的Ti02薄膜，并以苯酚的降解反应为模型，研究了纳米Ti02薄膜的光催化活性．结果表明薄膜晶粒大小为23．0nrn，呈锐钛矿型，沿(101)晶面具有择优取向性；10h内苯酚的降解率为66％，苯酚光催化降解反应符合一级动力学规律．     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to