大体积混凝土温度场高速求解方法的改进

在超松弛预条件共轭梯度法(SSOR-PCG)的基础上,提出了变初值的迭代方法.该方法用前一时间步的温度值作为下一时间步的初值,与原来方法相比,求解速度可提高1/3左右.采用该迭代解法编制了温度场有限元程序,并对某碾压混凝土重力坝的瞬态温度场进行了仿真计算.计算结果表明,该方法具有很快的求解速度,20万自由度的温度场计算,求解1次(1个时间步)只需31-s.     

阵列侧向电法测井的快速反演

在介绍阵列侧向电极系工作原理及快速正演计算的基础上,通过计算分析了Marquardt法线性反演过于依赖初值及迭代反演速度慢的不足。为避免迭代反演的缺陷,研究了采用BP神经网络进行测井快速反演的方法。通过对测井响应进行井眼校正等预处理,可有效减少网络训练所需样本数,提高反演效率。通过对比不同网络结构的计算精度与计算效率,选取了22个隐含层节点的3层网络,反演结果与真值吻合较好。该反演方法不需给定初值,不需迭代计算,反演100组参数用一般计算机仅耗时3 s。     

求一类多维函数总极值点的综合数值方法

本文综合三咱较为有效的求总极值的确定型方法和随机型方法，提出自动寻找好的初始迭代点以较为方便地获取一类多维函数的总极值点的数值方法，这种方法只需在求局部极值算法程序中加入一个初值点选择模块就可获得总极值点求解程序，多个算便表明，该方法对一类多维函数的总极值点求解是很有效的。     

旋转声源延迟时间方程求解的数值研究

为提高气动噪声时域数值算法的计算速度,针对亚音速匀速圆周运动的点声源,将延迟时间方程的求解问题转化为求抛物线与余弦曲线的交点,转化后的方程形式简洁并且数值计算效率更高.使用分段二次函数对延迟时间方程中的余弦函数进行替换,得到一种新的高精度迭代初值计算方法,并分别采用Newton迭代和Halley迭代算法求解延迟时间方程.研究表明:相对于通常的固定初值给定法,所提出的分段二次近似迭代初值计算方法可以减少约20％的计算时间,且Halley迭代算法具有较好的计算效率和收敛特性.     

多层框架计算的位移迭代法

以位移为未知量，导出求解多层框架的迭代格式，并详细讨论迭代初值的选取方法。与传统的迭代法相比，未知量数目大大减少，公式推导容易理解，迭代过程直观，书写量小，适当选取初值可减少迭代次数。文后给出算例。     

钢管混凝土拱桥扣索一次张拉索力优化改进算法

为避免施工中反复调索的繁琐工作,同时保证钢拱肋松索成拱后线形满足期望要求,基于零阶优化法,运用大型有限元分析软件ANSYS,开展钢管拱肋扣索一次张拉索力优化研究. 提出基于扣索内力法确定索力迭代初值并在各迭代子步中对程序自动搜索值进行宏观调整的改进算法. 算例表明：改进算法可提高迭代效率和计算精度,按优化出的索力和预抬量进行施工控制,钢拱肋松索成拱线形与设计值吻合良好,克服了传统力学法调索中存在的较大马鞍形变形问题.     

无机物及化学反应热力学计算软件

在建成的无机热力学数据库和水溶液热力学数据库的基础上，利用ＦｏｘＰｒｏ数据库管理系统的数据检索和查询功能以及Ｃ＋＋语言的计算功能，编制了一套热力学计算软件．该程序可完成任何温度下气、固体和水溶液中离子、分子和化学反应（电极反应）的热力学计算等．程序可自动检索库中的数据，用户可通过键盘输入缺少的数据或修改已有数据，可自动配平化学反应（电极反应）方程式，可自动生成水溶液中分子的电离反应．程序设计简单，代码少，运算速度快，计算结果准确，通用性较好．     

多元混合物相包线的Newton-Raphson算法

详细介绍了一种计算多元混合物相包线的Newton Raphson多变量迭代算法。以Newton Raphson方法为代表的多变量迭代算法 ,其关键在于选择迭代变量和计算初值。在每一计算点分析各变量变化的敏感性 ,选择出适当的指定变量和迭代变量 ,并利用已求点的性质 ,通过两点三次样条插值为新计算点提供初值。对 4种典型的油气藏混合流体的相包线进行了计算 ,结果表明 ,该算法对于不同组成特点的多组分流体混合物均可以稳定、快速地收敛。相包线上临界点、温度和压力极值点的计算结果与丹麦相态计算软件包的计算结果相符。     

一种配电网潮流计算混合算法

针对牛顿—拉弗森法对初值反应敏感的固有缺陷，利用配电网的辐射状结构特点，提出了一种配电网潮流计算混合算法，使用逆流—顺流法的第一次迭代结果作为牛顿—拉弗森法的计算初值，既解决了牛顿—拉弗森法的初值敏感性问题，又提高了收敛速度．测试结果表明，混合算法在迭代次数和收敛速度上有优势．     

一种电力网络潮流计算的综合算法

针对牛顿-拉夫逊法对初值要求严格,迭代速度快的特点,利用电力网的结构特点,使用高斯-塞得尔迭代法的第一次迭代结果作为牛顿-拉夫逊法的计算初值。这样既解决了牛顿-拉夫逊法对初值要求高的问题,又提高了收敛速度。计算结果表明,综合算法在迭代次数和收敛速度上有优势。     

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