Information structure analysis for quantitative assessment of mineral resources and the discovery of a silver deposit     

Wang  Yutian  Tan  Bingqi  Wang  Yifeng  Wu  Jiangtao 《Natural Resources Research》1994,3(4):284-294

We propose an information-structure-analysis (ISA) method to quantify the correlations between quantitative and qualitative variables as well as within each type of variable. This method is applied to the evaluation of mineral resources in the western Zheijiang Province of China. The district contains a number of silver-bearing Fe–Cu–Pb–Zn mineral deposits near igneous complexes and FeCuPbZn zones away from the complexes. Silver anomalies occur not only in the known Fe–Cu–Zn–Pb deposits, but also in the country rock, suggesting the possible existence of silver deposits far from the igneous complexes.The tonnage distribution of silver is modeled by Monte Carlo simulation. This simulation is conducted on the basis of the correlations between silver (Ag) and lead (Pb), since no known data on silver is available. The known tonnage distribution of lead in 11 control cells was used to approximate the tonnage distribution of silver in the Monte Carlo simulation. With ISA and Monte Carlo methods, the total amount of potential polymetallic resources in 49 cells in the western Zhejiang Provice is predicted. Significantly, a deposit with about 24 tonnes of silver has been found within our exploration target area.  相似文献   

China's small town urbanization program: Criticism and adaptation     

Tan KC 《GeoJournal》1993,29(2):155-162

China's 12,000 designated towns and more than 40,000 rural market towns have experienced a major transformation since the institution of rural reforms in the late 1970s. Rural industrialization based on the concept of leaving the soil but not the village, entering the factory but not the town has contributed to the revitalization of many small towns. But this rural urbanization has also brought about a number of problems in the countryside, leading many to propose the adoption of the concept ofleaving the soil and the village as another basis of China's small town urbanization. This essay attempts to examine this transformation, particularly the recent criticism and adjustment made to the small town urbanization program.  相似文献   

“三角形法”在区域国土资源综合评价中的应用^*——以湖北大别山区为例     

谭传凤 《地理研究》1990,9(3):57-67

本文建立了国土资源评价的指标系统,应用“三角形法”进行了综合评价,高度概括了区域国土资源的宏观特征。  相似文献   

An electrochemical study of pyrite oxidation in the presence of carbon coatings in cyanide medium     

H. Tan  D. Feng  J.S.J. van Deventer  G.C. Lukey 《International Journal of Mineral Processing》2006,80(2-4):153-168

The anodic and cathodic behaviour of pyrite with clay and different carbon coatings of activated carbon, graphite and carbonaceous matter in cyanide medium was investigated using the potentiodynamic method. The presence of clay coating did not change the polarisation curve appearance for either the anodic oxidation of pyrite or the cathodic reduction of oxygen or the potential of the current plateau, but only decreased the plateau current especially at a higher coating thickness. The presence of the carbon coatings marginally shifted the rest potential for pyrite to a more anodic position and slightly changed the polarisation curve appearance for pyrite oxidation. The current density for pyrite oxidation largely increased in the presence of the carbon coatings, the potential at the plateau shifted to more cathodic positions, and the plateau width became smaller. These effects became more noticeable at a higher coating thickness. The activated carbon, graphite and carbonaceous matter coatings performed similarly in affecting pyrite oxidation at a similar thickness. The carbon coatings significantly increased the limiting current densities for oxygen reduction on pyrite, and the limiting current plateau became steeper at a higher coating thickness. The carbon coatings increased the limiting current density for oxygen reduction to a similar extent at a low coating thickness, but increased to varied extents at a higher coating thickness. The carbon coatings also greatly increased the cathodic current density for gold reduction on pyrite. The enhancement of pyrite oxidation and oxygen or gold reduction on pyrite by the carbon coatings was likely attributed to the electrochemical interaction between pyrite and the carbon materials with electron-rich surfaces and high conductivity. The presence of the carbon coatings significantly increased the oxidation of pyrite in aerated cyanide solutions and the preg-robbing of pyrite especially at a higher coating thickness.  相似文献   

中国近海初级生产力的遥感研究及其时空演化     

檀赛春  石广玉 《地理学报(英文版)》2006,16(4):447-457

1 Introduction Ocean primary productivity controls the exchange of carbon dioxide at the air-sea interface and plays an important role in the global carbon cycle and climate change. Most oceanographic research on primary productivity has focused on the ma…  相似文献   

Dissolved trace elements in river water: spatial distribution and the influencing factor, a study for the Pearl River Delta Economic Zone, China   总被引：1，自引：0，他引：1  

T. P. Ouyang  Z. Y. Zhu  Y. Q. Kuang  N. S. Huang  J. J. Tan  G. Z. Guo  L. S. Gu  B. Sun 《Environmental Geology》2006,49(5):733-742

Twenty-nine water samples were collected from different river channels of the Pearl River Delta Economic Zone, China. An inductively coupled plasma-mass spectromonitor (ICP-MS) was used to measure concentrations of the trace elements in these samples. The results suggest that the average concentrations of rare earth elements in river water show an increasing trend from the West River, the North River, the rivers of the Pearl River Delta, and the Shenzhen River to the East River. Relatively high concentrations of heavy metals appear in the East River, the rivers of the Pearl River Delta and the Shenzhen River, while the West River and the North River have relatively low heavy metal concentrations. Trace element concentrations in samples collected near urban or industrial areas are much higher than those of samples collected from distant areas, away from urban and industrial areas. After natural conditions, human activities have significant influence on the trace element concentrations in river water. This trace element concentration’s spatial distribution in the river water from the Pearl River Delta Economic Zone is actually an integrated effect of natural conditions and human activity.  相似文献   

加强工程施工项目管理措施与建议     

谭永强 《中国煤田地质》2005,17(5):131-132,138

结合项目施工管理的经验,从建立项目管理班子、项目评估和合同评审签订、人力资源的优化配置、强化劳务管理、责任成本管理、建立激励约束机制六个方面来探讨加强工程项目管理办法,并同时提出了加强工程项目管理的具体措施与建议.  相似文献   

Ekman动量近似下中间边界层模式中的风场结构   总被引：2，自引：0，他引：2  

Tan Zhemin  Wang Yuan 《大气科学进展》2002,19(2):266-278

发展了一个准三维的、中等复杂的边界层动力学模式，该模式包含了EKman动量近似下的惯性加速度和Blackadar的非线性湍流粘性系数，它进一步改进了Tan和Wu(1993）提出的边界层理论模型。该模型在数值计算复杂性上与经典Ekman模式相类似，但由于包含了Ekman动量近似下的惯性项，使得该模式比传统Ekman模式更近于实际过程。中详细地比较了该模式与其他简化边界层模式在动力学上的差异，结果表明：在经典的Ekman模式中，由于忽略了流动的惯性项作用，导致在气旋性切变气流（反气旋性切变气流）中风速和边界层顶部的垂直速度的高估（低估），而在半地转边界层模式中，由于高估了流动惯性项的作用，结果与经典Ekman模式相反。同样，该模式可以应用于斜压边界层，对于Ekman动量下的斜压边界层风场同时具有经典斜压边界层和Ekman动量近似边界层的特征。  相似文献   

工业革命以来青藏高原与南极冰芯高分辨率甲烷记录对比研究     

徐柏青  姚檀栋  Chappellaz J 《冰川冻土》2002,24(5):477-483

自工业革命以来全球大气CH4含量呈快速的增长趋势, 但达索普冰芯记录所显示的北半球中低纬度地区大气CH4增长的启动时间要晚于极地冰芯记录近100 a. 由于受北半球人类活动CH4排放、CH4在大气中的寿命及大气中CH4的传输等过程的影响, 最近150 a以来, 中低纬度大气CH4与南极大气CH4含量在不同的时段表现出不同的净积累量和增长速率, 且20世纪两次世界大战期间达索普冰芯记录明确显示出人类活动排放的减缓使大气CH4呈负增长. 对比研究认为, 到20世纪中叶人类活动的甲烷排放已达到极高值, 中低纬度大气中CH4增长率及年积累逐步趋于平稳且略有降低. 可以认定, 工业革命以来中低纬度地区大气CH4与南极大气CH4含量的变化在不同的时段在受控于人类活动影响的同时, CH4在大气中的行为和传输过程以及东亚中低纬度季风气候的影响决定了两地之间大气CH4含量变化存在显著的差异.  相似文献   

冰芯记录中末次间冰期-冰期旋回气候突变事件的研究进展   总被引：9，自引：2，他引：9  

王有清  姚檀栋 《冰川冻土》2002,24(5):550-558

冰芯记录中的气候变化是古气候研究中的重要组成部分. 极地、中低纬度和热带地区的冰芯记录表明, 在冰期间冰期旋回大尺度气候变化背景下, 全球经历了一系列数百年至千年时间尺度的快速气候突变事件, 诸如末次间冰期的干冷事件、末次冰期的DansgaardOeschger事件、 Heinrich事件和Younger Dryas事件等, 虽然这些穿插在冰阶中的暖湿气候事件、间冰阶中的干冷气候事件的成因、机制和影响范围还存在明显的不确定性. 主要介绍不同区域冰芯记录中末次间冰期冰期旋回这些气候突变事件发生的时间、过程和机制等的研究进展.  相似文献