Quantitative analyses of the spatial distribution of fault structures can provide a theoretical basis for forecasting prospective ore deposits. Characteristics and complexity of fault structure distribution in the Qit...Quantitative analyses of the spatial distribution of fault structures can provide a theoretical basis for forecasting prospective ore deposits. Characteristics and complexity of fault structure distribution in the Qitianling area, Southern Hunan Province, China, were quantitatively calculated and appraised by fractal and multifractal methods to evaluate the relation between fault structures and ore-prospecting potential. The results show that the lengths of faults can be modeled as multifractals. Multifractal spectra evidently reflect the characteristics of the scaling of fault structures. The box- counting dimension value （D） of fault structures is equal to 1.656, as indicates complexity of the spatial distribution of faults and favorable structural conditions for the formation of ore deposits. Moreover, the D values of sub-regions were calculated and isopleths of their fractal dimension values were plotted accordingly. Overlay analyses of isopleths of fractal dimension values and distributions of known ore deposits show that areas with the larger fractal dimension values of fault structures have more ore deposits. This spatial coupling relationship between D values and ore deposits can be used to forecast and explore other ore deposits. On the basis of complexity theory for ore-forming systems, three exploration targets with high D values were delineated as prospective ore deposits.展开更多
Commercially pure titanium( CP Ti) sheets show typical planar anisotropy due to inherently crystallographic texture and rolling process. To characterize the initial,planar,plastic anisotropy of CP Ti sheets in forming...Commercially pure titanium( CP Ti) sheets show typical planar anisotropy due to inherently crystallographic texture and rolling process. To characterize the initial,planar,plastic anisotropy of CP Ti sheets in forming process,uniaxial tensile tests of cold-rolled TA1 sheets at 0°,45° and 90° to the rolling direction were performed at room temperature,corresponding stress-strain curves and Lankford coefficient( r value) were obtained. Based on Hill'48 and Barlat'89 yield criteria,the anisotropic behavior of TA1 sheets was investigated. In order to verify the accuracy of two models,the experimental values of yield stress and r were compared with predicted ones. It revealed that Barlat '89 criterion with M = 6 is the best agreement with experimental data,and the obtained model can be used in the simulation of forming process.展开更多
Geological, geophysical, geochemical and remote sensing comprehensive studies show that big ore-prospecting potentiality is contained in the eastern section of the Gangdise Mountains, Tibet. There are various minerali...Geological, geophysical, geochemical and remote sensing comprehensive studies show that big ore-prospecting potentiality is contained in the eastern section of the Gangdise Mountains, Tibet. There are various mineralization types with dominant types of porphyry and exhalation. According to their relations with tectonic evolution, they are divided into four kinds of metallogenic series as follows: magmatic type (Cr, Pt, Cu, Ni) and exhalation type (Cu, Pb, Zn, Ag) ore deposit series related to Neo-Tethys oceanic crust subduction action (125-96 Ma); epithermal type (Au, Ag, Pb, Zn, Sb), altered fractured rock type (Cu, Mo) and skarn rock type (Cu) ore deposit series related to arc-continental collision; porphyry type (Cu, Mo), cryptoexplosion breccia type (Cu, Au, Pb, Zn), shear zone type (Au, Ag, Sb) and skarn rock type (Cu, Fe) ore deposit series with relation to post-orogenic extensional strike-slip. From subductive complex to the north, zoning appears to be crystallization differentiation type (segregation type)-shear zone type (altered rock type)-skarn rock type, epithermal type-porphyry type-porphyry type and exhalation type-exhalation type-hydrothermal filling-replacement type. The ore deposit is characterized by multi-places from the same source, parity and multi-stage, hypabyssal rock from the deep source and poly genetic compound as a whole.展开更多
This paper is aimed at presenting some suggestions to candidates who are taking the IELTS to get higher marks in speaking section.The first suggestion is from psychological aspect,using a variety of self-help material...This paper is aimed at presenting some suggestions to candidates who are taking the IELTS to get higher marks in speaking section.The first suggestion is from psychological aspect,using a variety of self-help materials to improve confidence.The second is to take a close look at the marking criteria of IELTS and make good use of it.The third encourages students to form a habit of thinking critically through invoking a range of academic perspectives.Evidences show that the suggestions are effective in raising scores on the speaking component since they have ever been applied to some students of the author.展开更多
基金financially supported by the China Geological Survey Project(Grant No.1212011121101)
文摘Quantitative analyses of the spatial distribution of fault structures can provide a theoretical basis for forecasting prospective ore deposits. Characteristics and complexity of fault structure distribution in the Qitianling area, Southern Hunan Province, China, were quantitatively calculated and appraised by fractal and multifractal methods to evaluate the relation between fault structures and ore-prospecting potential. The results show that the lengths of faults can be modeled as multifractals. Multifractal spectra evidently reflect the characteristics of the scaling of fault structures. The box- counting dimension value （D） of fault structures is equal to 1.656, as indicates complexity of the spatial distribution of faults and favorable structural conditions for the formation of ore deposits. Moreover, the D values of sub-regions were calculated and isopleths of their fractal dimension values were plotted accordingly. Overlay analyses of isopleths of fractal dimension values and distributions of known ore deposits show that areas with the larger fractal dimension values of fault structures have more ore deposits. This spatial coupling relationship between D values and ore deposits can be used to forecast and explore other ore deposits. On the basis of complexity theory for ore-forming systems, three exploration targets with high D values were delineated as prospective ore deposits.
基金Sponsored by the Key Technologies R&D Program(Grant No.2011BAE13B05)the National Natural Science Foundation of China(Grant No.51075031)
文摘Commercially pure titanium( CP Ti) sheets show typical planar anisotropy due to inherently crystallographic texture and rolling process. To characterize the initial,planar,plastic anisotropy of CP Ti sheets in forming process,uniaxial tensile tests of cold-rolled TA1 sheets at 0°,45° and 90° to the rolling direction were performed at room temperature,corresponding stress-strain curves and Lankford coefficient( r value) were obtained. Based on Hill'48 and Barlat'89 yield criteria,the anisotropic behavior of TA1 sheets was investigated. In order to verify the accuracy of two models,the experimental values of yield stress and r were compared with predicted ones. It revealed that Barlat '89 criterion with M = 6 is the best agreement with experimental data,and the obtained model can be used in the simulation of forming process.
文摘Geological, geophysical, geochemical and remote sensing comprehensive studies show that big ore-prospecting potentiality is contained in the eastern section of the Gangdise Mountains, Tibet. There are various mineralization types with dominant types of porphyry and exhalation. According to their relations with tectonic evolution, they are divided into four kinds of metallogenic series as follows: magmatic type (Cr, Pt, Cu, Ni) and exhalation type (Cu, Pb, Zn, Ag) ore deposit series related to Neo-Tethys oceanic crust subduction action (125-96 Ma); epithermal type (Au, Ag, Pb, Zn, Sb), altered fractured rock type (Cu, Mo) and skarn rock type (Cu) ore deposit series related to arc-continental collision; porphyry type (Cu, Mo), cryptoexplosion breccia type (Cu, Au, Pb, Zn), shear zone type (Au, Ag, Sb) and skarn rock type (Cu, Fe) ore deposit series with relation to post-orogenic extensional strike-slip. From subductive complex to the north, zoning appears to be crystallization differentiation type (segregation type)-shear zone type (altered rock type)-skarn rock type, epithermal type-porphyry type-porphyry type and exhalation type-exhalation type-hydrothermal filling-replacement type. The ore deposit is characterized by multi-places from the same source, parity and multi-stage, hypabyssal rock from the deep source and poly genetic compound as a whole.
文摘This paper is aimed at presenting some suggestions to candidates who are taking the IELTS to get higher marks in speaking section.The first suggestion is from psychological aspect,using a variety of self-help materials to improve confidence.The second is to take a close look at the marking criteria of IELTS and make good use of it.The third encourages students to form a habit of thinking critically through invoking a range of academic perspectives.Evidences show that the suggestions are effective in raising scores on the speaking component since they have ever been applied to some students of the author.
