A3钢电弧喷锌及锌涂层的耐蚀性

选择不同的喷涂工艺参数，使用沈阳工业大学研制的ＸＤＰ－２电弧喷涂机，在Ａ３钢上喷锌及喷锌加封闭等防腐处理，采用中性盐雾试验，浸泡试验不同喷涂工艺参数方法对徐层耐蚀性的影响及喷锌对Ａ３钢基体的保护效果，实验表明：喷涂工艺参数对涂层耐蚀性影响较大。喷锌、尤其喷锌封闭对Ａ３钢基体有很好的保护效果。     

伞齿轮精锻模超塑成形热喷涂层的超塑性固相扩散焊接

本文研究了３Ｃｒ２Ｗ８ＶＡ钢伞齿轮精锻模型腔火焰喷涂Ｇ１１２ＷＣ合金层及在模具精密成形时涂层的超塑性扩散焊接。在８２０℃，应变速率ε为３×１０－４ｓ－１的压缩条件下．基材和涂层均发生超塑协调变形，实现稳定可靠的超塑固相连接。研究表明，此时涂层孔洞闭合，涂层颗粒间界及涂层与基材的结合界面完全焊合。超塑性扩散焊接涂层的结合强度与高频和火焰重熔涂层相当，其耐磨性比高频重熔和火焰重熔高２０％～３０％，比改善前３Ｃｒ２Ｗ８ＶＡ模具高达６０％以上。     

酸度对A3钢在CO2的3%NaCl溶液中的腐蚀影响及缓蚀研究

利用失重法和电化学方法研究了酸度对Ａ３钢在ＣＯ２的３％氯化钠溶液中的腐蚀影响和咪唑类缓蚀剂ＨＡ,ＨＢ的缓蚀及缓蚀机理。结果表明：酸度对Ａ３钢在ＣＯ２的３％氯化钠溶液中腐蚀影响较大,与ＨＡ,ＨＢ的缓蚀效果差不多,是以控制阴极为主的混合型缓蚀剂。     

电厂锅炉管的高温腐蚀及金属陶瓷涂层防护

对火电站锅炉过热器用钢钢研１０２、Ｔ９１、ＴＰ３４７进行了高温氧化及模拟煤燃烧时碱金属硫酸盐（Ｎａ２ＳＯ４Ｋ２ＳＯ４）沉积在金属表面而发生的热腐蚀进行了腐蚀动力学研究，并针对２００ＭＷ发电机组常用的１０２钢采用表面喷涂Ｃｒ３Ｃ２－ＮｉＣｒＡｌ金属陶瓷涂层以提高其热腐蚀抗力．结果表明，高温氧化性能ＴＰ３４７钢最好，氧化速率符合抛物线规律；而１０２钢的氧化速率几乎呈直线规律．热腐蚀实验中，３种整体材料腐蚀后的质量增加都接近直线规律，说明它们抗热腐蚀的性能都比较差，涂层能有效的隔离腐蚀介质，防止基体氧化和腐蚀     

焊接热影响区组织对腐蚀疲劳的影响

利用焊接热模拟技术，在Ｇｌｅｅｂｌｅ－１５００热模拟机上模拟了ＨＡＺ粗晶区和正火区组织，采用四点弯曲疲劳法测定了Ａ５３７钢的热模拟组织在３．５％ＮａＣｌ水溶液和空气中的裂纹扩展速率，并测定了组织的电化学极化曲线，分析了各种不同组织对ｄａ／ｄｎ－△Ｋ关系的影响，研究了模拟ＨＡＺ组织的腐蚀疲劳机理。     

钢套钢直埋蒸汽管道外套管的腐蚀与防护

本文分析了钢套钢直埋蒸汽管道外套钢管在土壤介质中受到电化学腐蚀的机理，同时提出防腐涂层与阴极保护联合保护的解决方案。     

3％NaCl溶液中55％Al－Zn－1．6％Si合金镀层电化学参数测定及电偶腐蚀的电化学行为

提出了一种弱极化曲线测量数据计算机处理方法，并计算了５５％Ａｌ－Ｚｎ－１．６％Ｓｉ合金镀层在３％ＮａＣｌ溶液中腐蚀过程的电化学参数，研究了镀件在３％ＮａＣｌ溶液中发生整体腐蚀加速的机理．结果表明，镀层表面微电偶局部腐蚀的发展形成了基体钢与镀层金属的宏观电偶腐蚀，电偶电位Ｅｇ随时间的正移，使镀层金属的溶解电流密度迅速增大，钢基体受到的保护效应减小．     

陶瓷涂层的火焰喷涂及其耐磨性能

本文介绍了采用氧乙炔火焰喷涂Ａｌ２Ｏ３－ＴｉＯ２陶瓷材料。对其耐磨性能和机理进行的试验研究结果表明，在Ａｌ２Ｏ３中加入一定量的ＴｉＯ２不仅使Ａｌ２Ｏ３可以采用氧乙炔火焰喷涂，并且涂层的孔隙率下降，抗压强度增加，耐磨性能提高。     

高温下等离子喷涂涂层的减摩和抗磨特性

采用等离子喷涂工艺以最佳工艺参数制得 Ｃｒ２Ｏ３涂层。在 ＳＲＶ高温摩擦磨 损试验机上测量了该涂层与Ａｌ２Ｏ３球对磨从室温到８００℃时的摩擦系数和磨损量，结 果发现摩擦系数和磨损量都随温度上升而下降。 ＡＥＳ和 ＳＥＭ分析和观察磨损表面结 果表明；常温时涂层磨损机制为断裂磨损；高温时磨损表面发生材料转移和塑性流动， 并且在涂层表面有致密保护膜生成，该致密保护膜不仅降低摩擦系数而且降低涂层磨损。 文中还讨论了负荷对摩擦系数和涂层磨损的影响。     

等离子喷涂搪瓷瓷釉涂层的耐腐蚀性能

通过添加改性剂改性瓷釉,采用等离子喷涂技术喷涂在Q235钢表面形成耐腐涂层,利用SEM等手段对其微观结构进行了分析和表征,用静态腐蚀实验和电化学腐蚀实验对涂层的耐腐蚀性能进行了研究。研究结果表明,所有涂层在碱性溶液中都基本不腐蚀;所有涂层在酸性溶液中的腐蚀程度都比基体钢板小,且改性剂为NiO的涂层的耐酸腐蚀性能稍优于改性剂为TiO_2的涂层;涂层的耐电化学腐蚀能力要优于基体钢板,且添加NiO的涂层的耐电化学腐蚀性能稍优于添加TiO_2的涂层。搪瓷瓷釉涂层在一定程度上提高了基体钢板的耐腐蚀性能。     

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.     

Features of Women''s language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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