Scaling the 3-D Mohr circle and quantification of paleostress during fluid pressure fluctuation – Application to understand gold mineralization in quartz veins of Gadag (southern India)

In this study, orientations of 157 quartz veins occurring in metabasalts of the Gadag region (Dharwar craton, southern India) are used to plot the 3-D Mohr stress circle, which provides information about relative stress/fluid pressure (P_f) conditions, as well as stress state during P_f fluctuation. To scale the 3-D Mohr circle, vein orientation data are integrated with (a) available estimates from fluid inclusions of highest recorded P_f (390 MPa) and lowest recorded P_f (50 MPa) and (b) intrinsic rupture criterion that empirically quantify rock properties. Based on the scaled 3-D Mohr circle, the absolute magnitudes of the three principal stresses are quantified for high and low P_f. Of 157 veins investigated here, 14 veins are identified as having favourable orientation for dilation at high as well as low P_f. These 14 veins have a mean strike of 150°, which is similar to the orientation of the gold-bearing quartz lodes reported in the region. The effective normal stress (σ′_n = σ_n−P_f) prevalent during dilation of fracture/fabric anisotropy with 150° strike is calculated to be −11.5 MPa at high P_f, and −1.0 MPa at low P_f. Thus, it is interpreted that in the Gadag region, a change in σ′_n of 10.5 MPa prevailed during P_f fluctuation and associated separation of gold from the fluid.     

Mapping and evaluation the process,pattern and potential of urban growth in China

In this paper, the night-time light (NTL hereafter) data obtained by the Defence Meteorological Satellite Programme's Operational Line scan System (DMSP/OLS) were used to extract urban light index (ULI) for analysing urban growth and patterns in China. A unit circle mode was established to perform a comprehensive analysis and calculation of the variation of various types of urban land covers. In order to verify the ULI ability in extracting urban spatial patterns, eight typical cities were selected to make a comparison therein using Landsat TM/ETM + data. The objectives of this research include: 1) mapping temporal process of the urban growth; 2) exploring spatial characteristics of eight typical cities; 3) analysing spatial distribution pattern of primary urban agglomerations, and 4) assessing potential and tendency for urbanization in the future. The research results indicate that: the spatial pattern features of ULI generally agree with those of the features of urban pattern extracted from Landsat TM data. The morphological change of the urban light space can reflect the objective characteristics of the evolution of urban space. The study further illustrated that the NTL Data are applicable for extracting urban space information and have the potential to deepen understanding of urban space expansion.     

1976年以来香港入境旅游关系圈变化及指示性

入境旅游是衡量一个旅游目的地发展和国际化程度的重要标志。本文引入社会学人际关系理论与地理学距离衰减理论相结合,提出入境旅游关系圈（ITRC）的三层结构概念模型：周边圈、洲内圈和洲际圈。随后,以香港为案例提出了香港入境旅游关系圈（HKITRC）概念模型假设与实际HKITRC变化的指示性假设。在1976-2013年香港各入境客源地的旅游统计数据的基础上,利用空间分层与时间分段的方法对40年来实际HKITRC的变化及指示性进行了深入的实证分析。研究结果验证了假设,总结得出了40年来实际HKITRC三层结构和其内部各地区的变化规律,也证明了实际HKITRC变化对签证政策、人口规模、政治归属、文化传统和经济兴衰这5种因素的指示性。研究对学界及业界认识旅游目的地入境旅游关系圈的变化规律及其指示作用有一定启发和现实意义。     

祁连山北麓地貌信息熵与山体演化阶段分析

利用定量化的手段分析地貌演化的阶段和趋势,是地貌学研究领域的一个重大的理论课题。在地理信息系统软件ArcGIS和ArcView的支持下,利用数字高程模型提取祁连山北麓的河网和流域。利用Strahler积分计算了各个流域的地貌信息熵,按照主夷平面的高度将祁连山北麓的各个流域分为不同的部分,它们具有不同的地貌信息熵值。结果显示,祁连山地区正在进入戴维斯侵蚀旋回的幼年期阶段。     

旋转体三维重建方法研究

提出了一种新的旋转体三维重建方法。在该方法的实现过程中，首先利用旋转平台获取了旋转体的影像，然后基于物方的空间圆重建方法精确测量旋转体的上口，从而得到旋转体的旋转轴，再根据影像的方位元素对影像进行纠正，使得旋转体的轮廓线在影像上的成像左右对称。最后直接用纠正后的影像精确计算旋转体的形状。在理论上讲，利用一张影像就可以实现旋转体的三维重建，但在本文中使用了多张照片，主要是为了获取整个旋转体的纹理。对实际的旋转体进行三维重建，结果证明该方法是有效的。     

圆曲线斜巷腰线标定方法探讨

根据伪倾角法标设腰线的原理，推导出圆曲线斜巷腰线标定的伪倾角计算公式。     

应用Rankine理论的主动土压力计算

应用应力圆将Rankine理论计算主动土压力的方法延伸至坡面具有倾斜角的粘性填土，得出主动土压力强度沿墙背呈非线性分布的规律。根据填土倾斜角对填土内摩擦角的相对关系，导出土压力大小及作用点深度的计算公式，并绘制出曲线，以备查用。     

东营三角洲高频旋回划分与浊积砂体预测

笔者运用高分辨率层序地层学理论和分析方法,利用钻井、测井及三维地震资料对三角洲内部基准面旋回的各种界面识别,进行基准面旋回的划分和对比研究,最后分析三角洲各期基准面旋回和浊积砂体的分布规律,从而对东营三角洲的岩性油气藏进一步勘探提供一些科学依据.