一维Burgers方程的格子Boltzmann模型

从对流扩散的角度给出了一维Ｂｕｒｇｅｒｓ方程的格子Ｂｌｏｔｚａｍａｎｎ模型， 模型的特点，并和模拟结果进行了比较。     

二维反应扩散方程的格子Boltzmann方法模拟

建立了二维反应的散方程五速四方格子模型的格子Boltzann方法，进行计算机模拟演化，分析模拟结果，并与SChen利用七速六方格子模型得到的结果进行比较，得出在模拟求解流速为零情况下的反应扩散方程时，这两种格子模型是一致的结论。     

完全气体格子Boltzmann热模型

为建立一种具有任意比热比的完全气体多速度格子 Boltzm ann热模型 ,引入粒子的势能来调整压能与热力学能的关系 ;利用 Chapm an- Enskog方法从 BGK型的格子Boltzmann方程推导出了 Navier- Stokes方程和能量方程。对一维正弦波形式的能量衰减过程进行了模拟 ,测得的热扩散率与理论预测值相吻合。还模拟了绕加热平板的二维强制热对流问题 ,结果合理     

格子Boltzmann方法中不同边界处理及不同体力项表达式的对比分析

简要介绍了格子Boltzm ann方法以及耦合温度的格子Boltzm ann方法,就LBM采用不同边界处理分别对二维方腔自然对流进行了模拟以及对比。同时,推导出LBM中更为完整的体力项的表达式,并采用简化的体力项与较完整体力项分别进行数值模拟,将结果进行了对比分析。模拟的结果与前人的结果吻合良好。     

一维有源扩散方程的格子B0ltzmann方法

给出了一维有源扩散方程的格子Ｂｏｌｔｚｍａｎｎ模型，从统计物理换有度导出了宏观有源扩散方程，确定了局域平衡分布函数Ｃｈａｐｍａｎ－Ｅｓｋｏｇ展开的待定系数，计算机模拟结果和理论结果一致。     

用格子Boltzmann方法计算椭圆柱绕流的阻力

用格子Boltzmann方法模拟椭圆柱绕流, 研究椭圆柱形状对阻力的影响. 对圆柱绕流问题进行了数值模拟, 阻力系数的数值计算结果与相关文献数值相符. 计算了当Re=200, 椭圆柱纵轴长度不变、 横轴长度逐渐变大时几种不同形状的椭圆柱绕流, 并用插值方法处理了曲线边界, 用动量转换法计算了曲线边界受力. 计算得到了不同形状椭圆柱绕流的流线、 涡线以及阻力系数随横轴/纵轴长度比的变化趋势. 通过分析流线和涡线的变化, 给出了阻力变化的机理.     

Burgers方程定态激波解的格子Boltzmann方法模拟

用一维５速格子Ｂｏｌｔｚｍａｎｎ方法推导一维Ｂｕｒｇｅｒｓ方程,采用Ｃｈａｐｍａｎ－Ｅｎｓｋｏｇ展开的局域平衡分布函数形式并由守恒方程确定其展开系数。最后用格子Ｂｏｌｔｚｍａｎｎ方法模拟了对流系数ｖ＝１,扩散系数Ｄ＝０．３３３３的一维Ｂｕｒｇｅｒｓ方程的激波解。计算机数值模拟结果与理论解析解精确吻合。     

圆柱绕流的格子Boltzmann模拟

针对流体力学中模拟圆柱绕流的边界层内部流动问题,采用格子Boltzmann方法,用两个分布函数分别定义涡量和流函数,得到用两个格子Boltzmann方程建立的模型。以数值为例,圆柱绕流的数值模拟结果符合经典的理论结果。与直接模拟Navier-Stokes方程相比,该方法计算模型简单,分布函数简单,易于计算。     

可压Euler方程的格子Boltzmann方法:二维情形

根据微观和宏观之间的质量、动量和能量守恒原理，构建了一个可用于模拟可压流体的D2V19格子Boltzmann模型，利用Chapman—Enskog分析可从该模型推导出宏观流体力学方程-Euler方程．利用该模型对三种典型激波管进行数值模拟并与Riemann解析解进行比较和分析，发现该模型能较好的捕捉激波，精度令人满意，证明了该模型对可压流体的适用性．该模型适用于气体多方指数为任意值的系统．     

Burgers方程的格子Boltzmann方法模拟

用一维格子Boltzmann方法构造O(ε^4)的Burgers方程模型．格子Boltzmann方法的数值模拟结果与具有特定边界条件的Burgers方程的解析解精确吻合．     

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…     

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。     

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     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.