铜超微粉末的表面改性及其抗氧化性能

采用液相化学还原法制备了粒径约为５０ｎｍ的铜粉。研究了高分子吸附对铜粉在空气中的稳定性影响及粉末在水溶液中的稳定性。分别采用表面包银和磷化处理的方法，提高了铜粉的抗化性能，使５０ｎｍ铜超微粉末能稳定地存在于空气中，磷化处理后铜粉末的氧化温度高于２２０℃。     

以抗坏血酸为还原剂的超细铜粉的制备及其热稳定性

采用液相化学还原法，以抗坏血酸为还原剂，制备了５００ｎｍ至７μｍ不同粒径范围的超细铜粉，研究了该法的制备工艺及偻末在空气中的热稳定性。采用葡萄糖预还原法制备了粒径为１μｍ的均匀超细铜粉，改善了铜粉末的粒度分布。研究了干燥过程对粉末团聚程度的影响。     

改进的溶胶-凝胶法制备超细铜粉

对溶胶－凝胶法进行了改进，由溶胶直接制备出超细铜粉，找到了制备超细铜的Ｇ分散剂及最佳制备条件，并获得了平均粒径为１０ｎｍ的铜粉。     

高分子保护化学还原法制备纳米Ag粉

以聚乙烯吡咯烷酮为高分子保护剂，以水合肼为还原剂，在水溶液中制备了平均粒径为３０～１００ｎｍ的球型银粉。结果表明：水合肼和ＡｇＮＯ＿３的比例较大、反应时间适当延长，有利于提高银粉产率。较高的反应温度和添加细小晶种有利于形成小晶粒银粉。保护剂与银盐的比例是影响银粉团聚和形状的关键参数，该比例为１：１时效果最佳，银颗粒彼此相互不团聚，颗粒呈球型，粒度小于１００ｎｍ。     

液相沉淀法制备纳米铜粉

用甲醛做还原剂,采用液相沉淀法制备铜钠米粒子.经TEM和XRD表征,粒子形貌为球形,平均粒径为30 nm左右,粒径分布窄,粒子分布均匀,无硬团聚,为立方晶系单质铜粉.该铜粉表面经钝化处理,提高了抗氧化的能力,可以在空气中保存.     

液相沉淀法制备纳米铜粉

用甲醛做还原剂，采用液相沉淀法制备铜钠米粒子．经TEM和XRD表征，粒子形貌为球形，平均粒径为30nm左右，粒径分布窄，粒子分布均匀，无硬团聚，为立方晶系单质铜粉．该铜粉表面经钝化处理，提高了抗氧化的能力，可以在空气中保存．     

电化学法制备纳米铜粉

在十二烷基硫酸钠、吐温80、苯、正丁醇、十二烷基硫醇和硫酸铜混合而成的乳液中,采用电化学合成的方法制备稳定的、粒径均匀的Cu纳米颗粒.采用XRD、TEM及FT-IR对所制备的Cu纳米颗粒的结构、形貌、粒径大小及表面键合性质进行表征.结果表明,制备的纳米铜粉为球型颗粒,分散较好,尺寸较为均匀,约为60~80 nm,并且具有立方晶型结构;得到的纳米铜颗粒表面含有一层有机物质,形成了包覆层较薄的核壳结构,这种包覆层阻止了纳米铜粉在空气中或水中的团聚和氧化,起到提高纳米铜颗粒的分散性和稳定性的作用.     

铜颗粒填充型铜-聚苯醚复合导电胶制备及性能研究

该文采用粒径在50 nm～10μm之间不同规格的铜粉制备导电胶,对铜粉粒径大小、纳米铜粉添加量、聚苯醚与四氢呋喃质量比以及不同表面修饰方式等对导电胶电阻率及弯曲强度的影响进行了研究,并采用扫描电子显微镜(SEM)方法研究了复合材料的微观形貌。结果表明,通过控制铜粉与聚苯醚的比例,可制得不同电阻率和弯曲强度的导电胶。在铜粉与四氢呋喃溶液质量比为1∶6、聚苯醚与四氢呋喃质量比为1∶8. 9,40℃下固化时间为4 h时可使制备时间最短,材料性能较好。     

超细铜粉粒径和形貌的研究

采用电解法、机械球磨法和化学法制备了超细铜粉 ,利用扫描电镜对其粒径和形貌特征进行了分析 ,讨论了各种制备方法对铜粉粒径、形貌特征产生的影响     

铜酞菁废水资源化处理工艺研究

以资源化处理铜酞菁废水为目的,采用沉淀-吹脱-SBR法处理铜酞菁废水,对于沉淀的铜采用葡萄糖-水合肼还原法制备超细铜粉。分析了投加量、水温、pH对处理效果的影响。结果表明:超细铜粉为0.3～0.9μm的类球形,出水能够达到国家一级排放标准。     

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