边界润滑条件下摩擦化学反应机理研究

对边界润滑条件下,摩擦化学反应中的应力效应和热效应进行了研究,研究结果表明,应力可激发摩擦化学反应,应力效应和热效应均可增强摩擦化学反应。摩擦化学反应中形成稳定化学反应膜时,试件的磨损量最低,摩擦系数是小,磨擦学系统的温度最低。     

含磷添加剂在植物油中的摩擦学性能

为了分析含磷添加剂在植物油中的摩擦学性能，选择磷酸三丁酯(TBP)和磷酸三苯酯(TPP)作为植物油添加剂，利用四球机对比法进行了摩擦磨损试验。分析了植物油与含磷添加剂之间的作用机理，含上述添加剂的植物油在摩擦过程中发生了摩擦化学反应，生成了由甘油脂和摩擦化学反应产物组成的边界润滑膜，从而改善植物油的摩擦学性能。结果表明，TBP和TPP能明显改善植物油的抗磨性，并有效提高植物油的承载能力。     

钢表面氧氮处理层对硫化烯烃润滑的作用

利用球－盘试验机研究了４０Ｃｒ钢表面氧氮处理层对添加剂硫化烯烃作用效果的影响，并利用多种表面分析仪器分析了其机理。结果表明，由于氧氮处理表面的氧化膜可促进化学反应膜ＦｅＳ的生成，加上该氧化膜本身的作用，使其摩擦表面上由ＦｅＳ和氧化铁组成的边界润滑膜更厚且结构更致密，导致硫化烯烃与氧氮处理表面的配合具有更好的抗擦伤和抗磨效果。     

硅酸乙酯在天然生漆膜表面的化学修饰

通过硅酸乙酯和生漆膜的化学反应,对天然生漆膜进行化学修饰.用红外光谱、扫描电子显微镜和热重法等,对该修饰膜进行测试表征.结果表明,漆膜易与硅酸乙酯发生化学反应并生成致密的漆酚硅聚合物修饰膜.与生漆膜相比,该修饰膜具有更优异的耐热性和耐酸碱腐蚀性能.     

润滑分子特性对纳米级流体膜失效的影响

为研究 nm级流体膜的失效情况 ,采用 NGY- 2型nm级膜厚测量仪 ,根据光干涉相对光强原理 ,对纯滚动点接触的中心区进行润滑膜厚度测量。观察不同载荷和速度下纯烷烃及加入少量酸时的流体膜厚度的变化情况 ,考察流体效应膜的失效情况。实验表明 :使用烷烃作润滑剂时 ,当压力增至某一定值时有一个临界点 ,当速度低于此点时 ,膜厚剧减 ,此时润滑膜不再具有流体特征 ,此点是润滑膜失效点 ,它与压力、速度、润滑剂的粘度以及分子极性有关。加入少量极性添加剂后所形成的润滑膜可承受较大的载荷 ,并能确保nm级流体膜不失效 ;在较高压力下 ,要在接触区形成流体膜就必须施加更高的速度或使用较大粘度的润滑剂 ;极性添加物的加入能提高流体膜的承载能力     

纳米级润滑膜失效实验研究

采用光干涉法相对光强原理对点接触中心区进行了润滑膜厚度测量,该方法在垂直方向的分辨率可达0．5nm,水平方向可达1 μm．讨论了膜厚与压力,速度和润滑油粘度之间的关系,观察和分析了流体润滑膜的失效现象．实验结果表明如果接触压力足够小或者润滑油粘度足够高,即使在一个很低的速度下也能清晰地观察到流体动压润滑效应．当压力增至某一定值,在膜厚—速度曲线上可观察到一个转折点,当速度降到此点以下时,润滑膜厚度将很快减小到几个分子层厚,此时,润滑膜不再具有流体润滑特征,即流体润滑膜失效．对不同粘度的润滑剂,失效点会出现在不同的速度和压力下．要使接触区在较高的压力下形成流体膜就必须施加更高的速度或使用更大粘度的润滑油．最后建立了失效点的压力、速度和润滑油粘度之间的关系．     

金属Ni阳极溶解与钝化的机理研究

本文采用动电位扫描方法研究了硫酸盐水溶液中的金属Ni阳极过程。金属Ni阳极溶解与钝化表现为电荷传递分步进行、并以失去第一个电子的电化学反应为控制步骤的不可逆电极过程。金属Ni阳极正常溶解速度与电解质溶液组成浓度无关,而钝化是由于阳极极化电位较高时失去第二个电子的电化学反应直接生成固态NiO成相膜复盖电极表面所引起。综合实验研究事实和理论分析结果,本文提出了金属Ni阳极溶解与钝化反应的可能机理。     

T302添加剂对摩擦副抗胶合性能影响

通过对T302添加剂的润滑性能及抗胶合性能试验研究,发现T302添加剂能显著改善滑动摩擦副的抗胶合性能及润滑油的润滑性能,通过分析磨斑表面X射线衍射图谱(XPS),发现该种添加剂作用下,摩擦副表面形成了聚合物膜,使得摩擦力减小了,随着载荷的增大,添加剂在摩擦热产生高温作用下,部分原子如C、S同表面金属发生化学反应,生成了FeSO4 ,FeS 等物质.结合咬死失效后的表面形貌及咬死失效后滑动摩擦副表观特征分析,分析了该种添加剂作用下抗咬死性能提高的原因.     

热压碳化硼表面自润滑膜的生成

研究了热压碳化硼表面自润滑膜的生成.在实验条件下,未经热处理的碳化硼摩擦副的摩擦因数由起始阶段的0.35～0.40,随滑行距离的增加而减小至0.25左右.对摩擦前后接触面进行X射线衍射分析,结果表明接触界面发生了摩擦化学反应,生成了B     

锌合金压铸射嘴身失效行为分析

针对锌合金压铸时射嘴身的早期失效问题,通过组织分析发现,射嘴身材料中存在着的大量夹杂物和网状碳化物的缺陷以及M300钢本身的高温回火脆性,是射嘴身失效的主要原因.压铸时高速高压的锌合金熔体会与M300钢发生化学反应,生成Fe-Zn相的腐蚀产物,在射嘴身内腔腐蚀出沟槽,而高速锌合金熔体的冲击应力又进一步诱发沟槽内裂纹的扩展,从而促使了早期失效行为的发生.     

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