小湾电站高边坡系统锚固与排水的优化设计方法

据小湾电站地下厂房进水口开挖高边坡的岩体结构与工程地质特征,采用基于结构面网络模拟的随机楔体稳定分析方法对边坡的稳定性进行了三维分析。进一步运用风险分析理论对边坡系统锚杆与预应力锚索的布置进行了优化设计,最后运用结构面网络模拟理论对排水方案进行了优化设计。     

Researches on Cartographic Database-Based Interactive Three-Dimensional Topographic Map

With the development of computer graphics, the three-dimensional (3D) visualization brings new technological revolution to the traditional cartography. Therefore, the topographic 3D-map emerges to adapt to this technological revolution, and the applications of topographic 3D-map are spread rapidly to other relevant fields due to its incomparable advantage. The researches on digital map and the construction of map database offer strong technical support and abundant data source for this new technology, so the research and development of topographic 3D-map will receive greater concern. The basic data of the topographic 3D-map are rooted mainly in digital map and its basic model is derived from digital elevation model (DEM) and 3D-models of other DEM-based geographic features. In view of the potential enormous data and the complexity of geographic features, the dynamic representation of geographic information becomes the focus of the research of topographic 3D-map and also the prerequisite condition of 3D query and analysis. In addition to the equipment of hardware that are restraining, to a certain extent, the 3D representation, the data organization structure of geographic information will be the core problem of research on 3D-map. Level of detail (LOD). space partitioning, dynamic object loading (DOL) and object culling are core technologies of the dynamic 3D representation. The objectselection, attribute-query and model-editing are important functions and interaction tools for users with 3D-maps provided by topographic 3D-map system, all of which are based on the data structure of the 3D-model. This paper discusses the basic theories, concepts and cardinal principles of topographic 3I)-map,expounds the basic way to organize the scene hierarchy of topographic 3D-map based on the node mechanism and studies the dynamic representation technologies of topographic 3D-map based on LOD, space partitioning, DOL and object culling. Moreover. such interactive operation functions are explored, in this paper, as spatial query, scene editing and management of topographic 3D-map. Finally, this paper describes briefly the applications of topographic 3D-map in its related fields.     

Computational study of tetrahedral Al–Si and octahedral Al–Mg ordering in phengite

 As part of a wider study of the nature and origins of cation order–disorder in micas, a variety of computational techniques have been used to investigate the nature of tetrahedral and octahedral ordering in phengite, K₂ ^[6](Al₃Mg)^[4](Si₇Al)O₂₀(OH)₄. Values of the atomic exchange interaction parameters J _n used to model the energies of order–disorder were calculated. Both tetrahedral Al–Si and octahedral Al–Mg ordering were studied and hence three types of interaction parameter were necessary: for T–T, O–O and T–O interactions (where T denotes tetrahedral sites and O denotes octahedral sites). Values for the T–T and O–O interactions were taken from results on other systems, whilst we calculated new values for the T–O interactions. We have demonstrated that modelling the octahedral and tetrahedral sheets alone and independently produces different results from modelling a whole T–O–T layer, hence justifying the inclusion of the T–O interactions. Simulations of a whole T–O–T layer of phengite indicated the presence of short-range order, but no long-range order was observed. Received: 8 August 2002 / Accepted: 14 February 2003 Acknowledgements The authors are grateful to EPSRC (EJP) and the Royal Society (CIS) for financial support. Monte Carlo simulations were performed on the Mineral Physics Group's Beowulf cluster and the University of Cambridge's High Performance Computing Facility.     

Global thermal and dynamical perturbations due to Cretaceous mantle avalanche

The numerical models of mantle convection agree to depict avalanches behaviour according to the level of endothermicity of the spinel → perovskite phase change. Their potential effects on the global thermal and dynamical states of the mantle have been computed thanks to a numerical code, which takes into account both the 400-km exothermic and the 660-km endothermic phase changes. The cycle followed by the avalanches is: local layering, destabilization of the 660-km thermal layer, travelling and spreading on the core, and reappearing of the local layering. Therefore, mantle convection is characterized by quiet periods of partial layering embedded in catastrophic events. During the avalanche, the amplitude of the surface velocity is multiplied by two, which would imply an enhanced plate tectonic and ridge activities. The global thermal effects of the avalanche are compatible with a high mantle temperature and an acceleration of Earth's rotation during the Cretaceous. They also offer a coherent explanation to locate the origin of mantle plumes both within the CMB and just below the transition zone.     

一次梅雨锋降水系统三维风场双、三雷达对比研究

2002年，“我国重大气候和天气灾害的形成机理与预测理论研究”项目首次启用三多普勒天气雷达组网对暴雨系统进行同步观测，作者使用MUSCAT技术对6月24日梅雨锋雨带上的一个中β系统进行了双、三多普勒雷达三维风场对比分析，表明大气中低层辐合线是此次暴雨系统的一个重要特征。     

重磁遗传算法三维反演中高速计算及有效存储方法技术

将地下场源区域规则划分成很多小长方体单元，并且通过反演确定这些单元的物性变 化，勾画出场源的分布图像，这种方式逐步成为重磁反演，特别是三维反演的重要方向；遗 传算法等非线性技术进行该类反演将逐步成为发展趋势. 本文指出，在应用遗传算法进行该 类反演过程中，隐含着数据量较大时超常规的计算量，它已成为制约该类反演充分发挥作用 的瓶颈问题；同时，本文提出了针对性的分离并存储几何格架的计算策略、以及独特的几何 格架等效压缩存储技术，可以从根本上提高非线性反演计算速度，为该类反演的有效应用奠 定了坚实的基础.     

长白山天池火山区上地壳三维速度层析成像

利用三维地震透射观测系统所获得的莫霍界面反射波对长白山天池火山区下方上地壳的三维速度细结构进行了反演计算，得到了研究区下方地壳内不同深度的P、S波速度层析成像和VP/VS扰动分布图像，结果表明，天池火山区及其周边速度结构所呈现出的非均匀性变化与该区的地质构造和岩浆系统的存在有着密切的关系，异常变化比较明显的低P波速度异常体分布和高VP/VS扰动体意味这些介质体处在“软化高温”的状态，这与该地区广泛分布的地热异常和低Q值结构的研究结果是一致的.     

论航空影像的纹理与描述

本文在前人研究的基础上，提出以中心像元的近邻像元，而不是近邻像元的组合，作为纹理基元，纹理基元的灰度统计规律反映出影像纹理的特征，这种特征可以用马尔柯夫随机场（ＭＲＦ）来描述，其特征参数可以作为纹理分类的依据。通过实验分析，证明本文的提法是合理的。     

The identification and criteria of short-term seismicity gap before a great earthquake

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3-D structural reconstruction of Moho in the Tangshan earthquake area by using inversion of curved interface

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