基于知识的冲压产品与工艺集成建模方法

结合当前智能设计技术的发展，研究了面向工艺设计的冲压特征建模方法，建立了单特征定义与冲压工艺性评价模型、工艺规则的集成机制；分析了工步排样中的知识集成策略，给出了集成工步排样总体事例模型和工序间关系分析模型的设计方法；总结了集成知识模型的几何处理技术，提出了基于CAD平台进行几何处理的基本原理。应用结果表明，集成知识模型能有效提高冲压工艺设计能力。     

薄壁铝型材挤压成形的一种有效模拟方法

基于大变形弹塑性有限元理论和有限体积法基本原理，建立了金属塑性成形的弹塑性UL有限元列式以及塑性流动中的有限体积控制方程．提出了有限元模拟系统到有限体积模拟系统的数据传递和信息继承方法。建立了铝型材挤压成形有限元/有限体积法复合模拟系统，对铝型材挤压过程进行了数值模拟，预示金属在成形中的塑性变形行为，从而为模具设计及工艺参数选取提供理论依据．     

基于事例推理的质量故障处理系统的研究

基于事例推理是人工智能中的一种重要推理技术。以质量管理系统的设计与开发为背景，在分析质量故障处理的特点和应用现状的基础上，提出了一种基于事例推理的质量故障处理方法。它克服了传统的基于规则推理系统获取、描述准确知识困难的瓶颈，提高了自学习能力。     

应用有限元法校核铝型材挤压模工作带设计

本文探讨了应用有限元法校核铝型材挤压模工作带设计的可能性，提出了计算方案及相关问题的处理方法     

薄壁铝型材挤压有限体积分步模拟

建立了铝型材挤压成形有限体积法分步模拟系统．研究了有限体积分步求解方法关键技术，实现了各分步有限体积模拟系统的数据传递和信息继承．在每一分步计算中，占用相对较少的计算机资源，可划分更为细致的有限体积网络．利用该方法成功地模拟了薄壁类铝型材挤压成形过程，并对成形中应力、应变及温度场分布的演化进行了分析．研究结果表明，有限体积分步法是模拟薄壁类铝型材挤压成形过程的有效方法．     

基于UG/OPEN的铝型材挤压模具设计系统开发

分析了铝型材挤压模具的设计流程,在铝型材挤压模具设计数据流图的基础上,以UG NX为开发平台,综合运用各种UG/OPEN开发技术开发了铝型材挤压模具设计系统,包括用户菜单、模具文件新建界面、截面数据处理、工艺参数处理、挤压模具结构设计与结构生成等模块.该设计系统与UG NX无缝集成,运行稳定可靠,大大提高了铝型材挤压模具的设计效率和质量.     

基于事例推理的短期负荷预测

将人工智能中的事例推理(CBR)技术引入到电力系统短期负荷预测中，针对传统规则专家系统知识获取的“瓶颈”问题，事例推理充分利用另一种知识资源(以往预测成功的例子)来解决新的预测问题．以前的预测行为作为历史事例以一定的结构和方式存储在事例库中，对于新的预测问题，从事例库中找寻相似事例，并利用其结论，确定新问题的解决方法．实际算例表明，对于短期负荷预测问题，基于事例推理的预测系统在预测精度上优于单一的数学模型，具有较强的实用性．     

初探不同挤压速度对铝型材挤压过程的影响

在实际操作过程中,作为铝型材挤压过程中的重点工艺条件之一,挤压速度的不同往往会直接影响到铝型材挤压产品的质量、模型的使用时间、生产的效率以及挤压力等,而挤压过程中的相关工艺参数是决定挤压工艺成功或失败的重要条件,也是铝型材挤压过程的重要影响因素.本文主要分析了挤压过程中因挤压速度不同,而导致的温度、模具荷载、材料流动等因素对铝型材挤压的影响,并总结出一定的规律.     

铝型材挤压有限元和有限体积对比模拟

研究了有限元法(FEM)和有限体积法(FVM)模拟金属塑性成形的基本理论和求解方法．针对铝合金门窗型材制品截面形状十分复杂、壁薄而成形坯料厚的具体特点，分别采用FEM和FVM对其挤压成形过程进行了对比模拟．结果表明，FEM计算效率高，但在模拟终成形阶段时，由于频繁的网格再划分，造成模拟结果严重失真；FVM避免了网格再划分问题，模拟精度高，但计算时间长．提出了采用FEM模拟铝型材挤压预成形，FVM模拟终成形的复合模拟方法，解决了料厚而壁薄这类铝型材挤压成形的数值模拟问题。     

基于B曲线插值约束的曲面变形技术

在CAD／CAS领域，随着基于样条曲线的模型逐渐成为主导趋势，进一步带动了高度自由曲面建模技术的发展．目前有关曲面的大量的研究致力于从标准显式曲面的几何参数生成到隐式曲面的基于边界的挤压变形处理，并产生了一系列有效的算法．然而，其繁琐的几何参数输入、过于复杂的数学计算局限了设计者的使用．笔者描述了直观、自然的自由曲面绘制，以及基于曲面上B样条曲线插值约束的曲面变形技术，从而进一步高效地实现了自由曲面的整体修改操作，并通过实验检验了其高效性．     

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