http://www.sciencedirect.com/science/article/pii/S1674987111001411

正Three-dimensional geological modeling(3DGM) assists geologists to quantitatively study in three-dimensional(3D) space structures that define temporal and spatial relationships between geological objects.The 3D property model can also be used to infer or deduce causes of geological objects.3DGM technology provides technical support for extraction of diverse geoscience information,3D modeling,and quantitative calculation of mineral resources.Based on metallogenic concepts and an ore deposit model, 3DGM technology is applied to analyze geological characteristics of the Tongshan Cu deposit in order to define a metallogenic model and develop a virtual borehole technology;a BP neural network and a 3D interpolation technique were combined to integrate multiple geoscience information in a 3D environment. The results indicate:(1) on basis of the concept of magmatic-hydrothermal Cu polymetallic mineralization and a porphyry Cu deposit model,a spatial relational database of multiple geoscience information for mineralization in the study area(geology,geophysics,geochemistry,borehole,and cross-section data) was established,and 3D metallogenic geological objects including mineralization stratum,granodiorite, alteration rock,and magnetic anomaly were constructed;(2) on basis of the 3D ore deposit model,23,800 effective surveys from 94 boreholes and 21 sections were applied to establish 3D orebody models with a kriging interpolation method;(3) combined 23,800 surveys involving 21 sections,using VC++ and OpenGL platform,virtual borehole and virtual section with BP network,and an improved inverse distance interpolation(IDW) method were used to predict and delineate mineralization potential targets (Cu-grade of cell not less than 0.1%);(4) comparison of 3D ore bodies,metallogenic geological objects of mineralization,and potential targets of mineralization models in the study area,delineated the 3D spatial and temporal relationship and causal processes among the ore bodies,alteration rock,metallogenic stratum,intrusive rock,and the Tongshan Fault.This study provides important technical support and a scientific basis for assessment of the Tongshan Cu deposit and surrounding exploration and mineral resources.     

HyLogger-3, a visible to shortwave and thermal infrared reflectance spectrometer system for drill core logging: functional description

Australian Geological Surveys are the custodians of a major national asset in the form of historically drilled and archived drill cores of the top few kilometres of the continent acquired by government agencies and companies over many decades. The AuScope National Virtual Core Library (NVCL) component of the AuScope Earth Model comprises geological/rock samples, technology, people and database/delivery infrastructure located in six nationally distributed nodes and is aimed at extracting additional value from this asset. The technology components of the NVCL comprise an integrated suite of hardware (HyLogger-3) and software (TSG-Core) systems for the imaging and hyperspectral characterisation of drill cores in their original core trays and the interpretation of their contained oxide, carbonate, hydrous and anhydrous silicate mineralogy. The HyLogger-3 includes state-of-the-art Fourier Transform Spectrometers that continuously measure calibrated spectral reflectance from nominal 10 by 18 mm fields of view. These spectra are in turn passed through a series of automatic and semi-automatic pre-processing and mineralogical unmixing algorithms. These, along with numerous other tools in TSG-Core, output a variety of mineralogical and image products for use by scientists in many branches of the earth sciences. This paper provides a functional overview of the HyLogging hardware and software tools available in each of Australia's Geological Surveys.     

Validation study of the distinct lattice spring model (DLSM) on P-wave propagation across multiple parallel joints

A validation study of the distinct lattice spring model (DLSM) for wave propagation problems is performed. DLSM is a microstructure-based numerical model, which is meshless and has advantages in modelling dynamic problems where stress wave propagation is important. To verify the applicability of DLSM to modelling wave propagation through a discontinuous medium, the virtual wave source (VWS) method is used to obtain analytical solutions for wave propagation across a jointed rock mass. Numerical modelling results of the commercial code UDEC are selected as the reference. The effects of particle size and lattice rotation angle on wave propagation are first studied. Then, the results of wave transmission across a single joint with a different joint stiffness and across multiple parallel joints with different joint spacings are derived with DLSM, UDEC and VWS. These results are in good agreement with each other. Therefore, the capability of DLSM to model P-wave propagation across jointed rock mass is verified, which provides confidence for the further application of DLSM to modelling more complex problems.     

高速网上3维海量地形数据的实时交互浏览的实现

针对高速网上3维海量地形数据传输和显示特点，提出了一套海量地形数据处理、存储方法，包括数据的预处理和数据的存储结构，数据存储有利于高速网络访问；并根据人的视觉生理特征，提出了一种多分辨率地形表示模板形成，较好地处理了实时交互游览地形的真实感和巨大数据需求之间的冲突。设计了一种适合网络实时传输海量地形数据的传输协议，使系统充分利用网络带宽同时又不浪费带宽。通过在中国高速互联试验网络NFSCNet上的大量演示，表明所提出的技术方案是切实可行的，证明了高速网对3维海量地形实时交互浏览的必要性和可行性。     

高频面波方法的若干新进展

面波多道分析方法(MASW)通过分析高频瑞雷波确定浅地表剪切波速度.在过去的20年中, 由于该方法具有非侵入性、无损、高效及价格低的特点, 越来越受到浅地表地球物理和地质工程学界的重视, 视为未来最有希望的技术之一.这篇综述论文将介绍中国地质大学(武汉)浅地表地球物理团队近年来在研究高频面波的传播理论和应用中取得的部分成果.非几何波是一种仅存在于浅地表介质, 尤其是未固结的沉积物中的独特的地震波.它的存在对快速而准确地获得表层S波速度有一定价值.我们的研究表明非几何波是一种具有频散特性的泄漏波.泄漏波的存在可能导致将其误认为瑞雷波的基阶或高阶能量, 从而造成模式误判.这种模式误判会导致错误的反演结果.我们通过求取高基阶分离后的瑞雷波格林函数证明虚震源法瑞雷波勘探的可行性.这个结果将极大地降低野外瑞雷波勘探成本.勒夫波多道分析方法(MALW)中未知参数比瑞雷波的少, 这使得勒夫波的频散曲线比瑞雷波的简单.因此, 勒夫波反演更稳定, 非唯一性更低.勒夫波数据生成的能量图像通常比瑞雷波的清晰, 并具有更高的分辨率, 从而可以更容易地拾取精确的勒夫波的相速度.利用雅克比矩阵分析波长与探测深度的关系表明对相同波长的基阶模式而言, 瑞雷波的探测深度是勒夫波的1.3~1.4倍; 而两种波的相同波长的高阶模式波的探测深度相同.我们也尝试了时间域勒夫波反演.按照勒夫波分辨率将地球模型剖分成了不同尺寸的块体, 利用反卷积消除了地震子波对勒夫波波形的影响, 通过更新每个块体的S波速度来拟合勒夫波波形, 从而获得地下S波速度模型.该方法不基于水平层状模型假设, 适用于任意二维介质模型.     

Installing single-propeller twin-rudder system with less asymmetric maneuvering motions

The inflow characteristics to each one of the rudders of single-propeller twin-rudder system are investigated. It is shown that this inflow is not parallel to ship's centerline. This may result in asymmetric maneuvering characteristic of the ship thereby reducing ship's maneuvering performance. For this purpose, a method of installing single-propeller twin-rudder system is proposed. This method is called “virtual zero rudder angle” arrangement. Here, each one of the twin-rudder is set at an angle corresponding to the inflow to the rudder. The improvement in ship's maneuvering characteristics with “virtual zero rudder angle” arrangement is investigated using experiments and numerical simulations for different ship types. It is shown that this arrangement may also improve ship's propulsion performance.     

An efficient method for rendering linear symbols on 3D terrain using a shader language

With the extensive application of virtual geographic environments and the rapid development of 3D visualization analysis, the rendering of complex vector lines has attracted significant attention. Although there are many rendering algorithms in 3D geographic information system (GIS), they are not sufficiently flexible to meet the requirements for rendering linear symbols composed of diverse colors and shapes. However, the interactive rendering of a scene and the accuracy of the symbols are important components for large-scale, complex vector lines. In this paper, we propose a graphics processing unit (GPU)-accelerated algorithm for rendering linear symbols on 3D terrain. Symbol rendering is embedded within the terrain-rendering process, and vector lines are encoded in a 3D texture and then transferred to the GPU. A set of visual properties are used to enrich the expression of symbols with the help of geometric operations in the fragment shader. A series of experiments demonstrate that the proposed method can be utilized for drawing various pixel-exact linear symbols and can achieve real-time rendering efficiency.     

虚拟现实技术及其在地球科学中的应用

虚拟现实技术以其具有的沉浸感、交互性、实时性、构想性等特点而越来越为广大地学工作者所关注。本文首先介绍了虚拟现实系统的组成,之后综述了近几年国内外地球科学部分领域应用虚拟现实技术的研究文献。与传统方法相比,虚拟现实技术在很大程度上提高了科学研究的效率,能提供更丰富的可视化和交互环境,使科学家能够操纵多达GB甚至TB级数据,以一种身临其境方式来对研究对象进行观察、分析和实时操作,而无需科研人员到达现场。通过虚拟现实系统,能将尽可能多学科的数据放到同一个环境下,增强科研人员研究问题的深度和广度,避免得出错误结论。同时能重塑不可再生资源,避免了在科学研究的同时对其造成的破坏,有助于科学知识在公众中的传播。与西方发达国家相比,我国的（沉浸式）虚拟现实技术在地学领域的应用还处在起步阶段,在拥有大量高精度LiDAR地形数据的活动构造等领域亟待引入该项技术,以一种全新的视野来重新审视地球科学研究,并推动该学科在未来的发展。     

虚拟土安全战略及其在县域土地可持续利用中的应用--以广西都安和田东县对比分析为例

运用"虚拟土战略",构建以县级为尺度的虚拟土安全战略评价体系,基于此体系对西部典型缺粮县(都安县)和产粮基地(田东县)的土地虚拟战略机制的评价基础上, 衡量对比两县是否具备实施虚拟土战略标准,最终提出有效"虚拟土"措施与对策,致使解决由于土地资源短缺所带来的粮食安全问题,同时提高县的经济、改善生态环境、使本县人们的逐步奔小康, 促进该县可持续发展.