各向异性矿化特征的分析与模拟 及其在储量估算中的应用

矿化作用往往是地质事件及局部过程共同作用的结果,导致矿体空间形态复杂多变、矿石品位呈各向异性、尺度不一的非线性空间变异模式.传统方法无论是在矿石量的计算方面还是在矿块内平均品位的确定上都存在多种误差,并且无法实现信息的动态管理及直观表达.文章以安庆铜矿中心矿区为例,采用对数块kriging与三维地学模拟技术相结合的方法...     

基于三棱柱的三维地质体建模及可视化研究

建立可视化的三维地质模型是地质信息可视化的一个研究重点,能够为各种地质现象描述提供科学依据。本文主要研究了基于三棱柱的模型构造,提出了三棱柱的改进数据结构和切割的构形以及算法,并且在VC6.0环境下,采用OpenGL作为图形开发工具,实现了三维地质体的可视化,解决了地质体剖切和基坑开挖等问题。     

Probing the Obscuring Medium Around Active Nuclei Using Masers: The Case of 3C 403

We report the first detection of a water megamaser in a radio-loud galaxy, 3C 403, and present a follow-up study using the VLA. 3C 403 has been observed as a part of a small sample of FR II galaxies with evidence of nuclear obscuration. The isotropic luminosity of the maser is 1200 L. With a recessional velocity of cz 17680 km s^–1 it is the most distant water maser so far reported. The line arises from the densest (> 10⁸ cm^–3) interstellar gas component ever observed in a radio-loud galaxy. Two spectral features are identified, likely bracketing the systemic velocity of the galaxy. Our interferometric data clearly indicate that these arise from a location within 0.1 (110 pc) from the active galactic nucleus. We conclude that the maser spots are most likely associated with the tangentially seen parts of a nuclear accretion disk, while an association with dense warm gas interacting with the radio jets cannot yet be ruled out entirely.     

异常结构三维综合系统的开发和应用

地球化学异常结构三维综合系统的开发和应用是为了满足地球化学多维异常体系的研究而逐步展开的。应用于深部找矿预测的多维异常结构方法,从钻孔岩芯直接采样,获得了具有真三维属性的地球化学数据,研究者迫切需要在三维场景下对所获三维地球化学数据进行解读和表达。异常结构三维综合系统(3D-MDAS)是利用三维可视化和地质体三维建模技术,在MapGIS K9平台上进行二次开发获得的。本系统实现了地上、地下数据模型的一体化显示,实现了实体模型与属性模型的耦合一体化显示,在此基础上还可以对异常结构进行空间分析,建立三维地球化学找矿模型。笔者详细阐述了三维异常结构3D综合系统的三维建模思路和技术,并用安徽马头矿区的实际应用成果给以说明。     

区域气候模式RegCM3应用研究综述

回顾了区域气候模式RegCM的发展历史,并对最近推出的RegCM3模式目前的应用进展情况进行了分类总结,同时讨论了今后的研究方向和其中存在的不足。     

徕卡三维激光扫描系统在建筑物精细建模中的应用

三维激光扫描技术作为一种新的测绘技术手段改变了传统的测量模式,利用三维激光扫描技术可以快速、高效、连续地获取海量的点云数据,通过处理可以快速得到被测目标的三维模型。本文主要结合徕卡Scan Station P40三维激光扫描系统介绍其在复杂建筑物精细建模中的应用,通过对点云数据及建模精度分析,得出了有益的结论。     

Structural evolution of the Bayanhongor region, west-central Mongolia

Most of previous models suggest that the Central Asia Orogenic Belt grew southward in the Phanerozoic. However, in the Bayanhongor region in west-central Mongolia, volcanic arc, accretionary prism, ophiolite, and passive margin complexes accreted northeastward away from the Baydrag micro-continent, and hence the region constitutes the southwestern part of a crustal-scale syntaxis close to the west. The syntaxis should be original, because presumably reorientation due to strike-slip faulting can be ignored. It is reconfirmed that the Baydrag eventually collided with another micro-continent (the Hangai) to the northeast. A thick sedimentary basin developed along the southern passive margin of the Hangai micro-continent. This region is also characterized by an exhumed metamorphosed accretionary complex and a passive margin complex, which are both bounded by detachment faults as well as basal reverse faults which formed simultaneously as extrusion wedges. This part of the Central Asia Orogenic Belt lacks exhumed crystalline rocks as observed in the Himalayas and other major collisional orogenic belts. In addition, we identified two phases of deformation, which occurred at each phase of zonal accretion as D1 through Cambrian and Devonian, and a synchronous phase of final micro-continental collision of Devonian as D2. The pre-collisional ocean was wide enough to be characterized by a mid-ocean ridge and ocean islands. Two different structural trends of D1 and D2 are observed in accretionary complexes formed to the southwest of the late Cambrian mid-ocean ridge. That is, the relative plate motions on both sides of the mid-ocean ridge were different. Accretionary complexes and passive margin sediments to the northeast of the mid-ocean ridge also experienced two periods of deformation but show the same structural trend. Unmetamorphosed cover sediments on the accretionary prism and on the Hangai micro-continent experienced only the D2 event due to micro-continental collision. These unmetamorphosed sediments form the hanging walls of the detachment faults. Moreover, they were at least partly derived from an active volcanic arc formed at the margin of the Baydrag micro-continent.     

直流电阻率法2.5维正演的外推瀑布式多重网格法

引入外推瀑布式多重网格法(EXCMG)求解2.5维直流电阻率有限元计算形成的大型稀疏线性方程组,结合基于地址矩阵的压缩存贮方式以及最优化离散波数,使得2.5维电阻率正演程序的计算速度大大提高而内存需求大大减小.研究结果表明:EXCMG法的收敛速度与网格尺寸无关,计算速度明显优于不完全Cholesky共轭梯度(ICCG)...     

一种基于立方体小栅格的K邻域快速搜索算法

提出了一种新的基于立方体小栅格的K邻域搜索算法。首先,采用二次划分的方法将点云划分到相应的立方体小栅格中;然后,为采样点所在的立方体小栅格确定最终子空间、内子空间和外子空间,结合采样点的球空间,就能很快确定该采样点的K邻域的搜索范围。与已有方法相比,该算法具有更高的搜索效率。     

Effects of N:P ratio of Artemisia ordosica on growth influenced by soil calcium carbonate

Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.