Induced polarization （IP） 3D tomography with the similar central gradient array combines IP sounding and IP profiling to retrieve 3D resistivity and polarization data rapidly. The method is characterized by high spa...Induced polarization （IP） 3D tomography with the similar central gradient array combines IP sounding and IP profiling to retrieve 3D resistivity and polarization data rapidly. The method is characterized by high spatial resolution and large probing depth. We discuss data acquisition and 3D IP imaging procedures using the central gradient array with variable electrode distances. A 3D geoelectric model was constructed and then numerically modeled. The data modeling results suggest that this method can capture the features of real geoelectric models. The method was applied to a polymetallic mine in Gansu Province. The results suggest that IP 3D tomography captures the distribution of resistivity and polarization of subsurface media, delineating the extension of abrupt interfaces, and identifies mineralization.展开更多
Vast grasslands are found in the walnut-fruit forest region of southern Kyrgyzstan,Middle Asia.Located above the worldwide unique walnutfruit forests and used for grazing,they play a pivotal role in the mixed mountain...Vast grasslands are found in the walnut-fruit forest region of southern Kyrgyzstan,Middle Asia.Located above the worldwide unique walnutfruit forests and used for grazing,they play a pivotal role in the mixed mountain agriculture of local farmers.Accordingly,these pastures are subject to an increasing utilization pressure reflecting the changing political and social conditions in the transformation process from a Soviet republic to an independent state.A first detailed analysis of mountain pasture vegetation in the Ferghana Range answers the following questions:What are the main plant community types among Kyrgyzstan's mountain pastures? What are the main environmental gradients that shape their species composition? Which phytogeographical distribution types are predominant? How does grazing affect community composition and species richness in these grasslands? Species composition was classified by cluster analysis;underlying environmental gradients were explored using DCA.A dataset of 395 relevés was used for classification,and a subset of 79 relevés was used in a DCA to analyze the correlation between vegetation,environment,and grazing impact.The investigated pastures were classified into four distinctive plant communities.The site factors altitude,heat load,inclination and grazing impact were found to be the major determinants of the vegetation pattern.A significant overlap between floristic composition and structural and spatial properties was shown.The majority of the species pool consisted of Middle Asian endemics and Eurosiberian species.However,disturbance-tolerant species played a significant role with respect to species composition and coverage of the herbaceous layer in vast areas of southern Kyrgyzstan's mountain pastures.In general,an intense grazing impact is clearly reflected by both species composition and structural variables of plant communities.The highly diverse and unique ecosystem is modified by an increasing utilization pressure.In order to maintain vital processes and functioning of this valuable ecosystem-in both economical and ecological terms-,it is indispensable to adopt appropriate pasture management strategies.展开更多
In this work, the 'retention time gradient effect' of gradient GC columns is intensively studied to establish some equations and formulas for structure calculation of chromatographic columns. In addition, the ...In this work, the 'retention time gradient effect' of gradient GC columns is intensively studied to establish some equations and formulas for structure calculation of chromatographic columns. In addition, the relevant computer programs are designed.展开更多
基金funded jointly by the National High Technology Research and Development Program(863 Program:No.2014AA06A610)special funds for basic scientific research business expenses of the Chinese Academy of Geological Sciences(No.YYWF201632)the National Major Scientific Instruments and Equipment Development Projects(No.2011YQ050060)
文摘Induced polarization （IP） 3D tomography with the similar central gradient array combines IP sounding and IP profiling to retrieve 3D resistivity and polarization data rapidly. The method is characterized by high spatial resolution and large probing depth. We discuss data acquisition and 3D IP imaging procedures using the central gradient array with variable electrode distances. A 3D geoelectric model was constructed and then numerically modeled. The data modeling results suggest that this method can capture the features of real geoelectric models. The method was applied to a polymetallic mine in Gansu Province. The results suggest that IP 3D tomography captures the distribution of resistivity and polarization of subsurface media, delineating the extension of abrupt interfaces, and identifies mineralization.
基金the joint project "The Impact of the Transformation Process on Human-Environmental Interactions in Southern Kyrgyzstan" supported by the Volkswagen Foundation
文摘Vast grasslands are found in the walnut-fruit forest region of southern Kyrgyzstan,Middle Asia.Located above the worldwide unique walnutfruit forests and used for grazing,they play a pivotal role in the mixed mountain agriculture of local farmers.Accordingly,these pastures are subject to an increasing utilization pressure reflecting the changing political and social conditions in the transformation process from a Soviet republic to an independent state.A first detailed analysis of mountain pasture vegetation in the Ferghana Range answers the following questions:What are the main plant community types among Kyrgyzstan's mountain pastures? What are the main environmental gradients that shape their species composition? Which phytogeographical distribution types are predominant? How does grazing affect community composition and species richness in these grasslands? Species composition was classified by cluster analysis;underlying environmental gradients were explored using DCA.A dataset of 395 relevés was used for classification,and a subset of 79 relevés was used in a DCA to analyze the correlation between vegetation,environment,and grazing impact.The investigated pastures were classified into four distinctive plant communities.The site factors altitude,heat load,inclination and grazing impact were found to be the major determinants of the vegetation pattern.A significant overlap between floristic composition and structural and spatial properties was shown.The majority of the species pool consisted of Middle Asian endemics and Eurosiberian species.However,disturbance-tolerant species played a significant role with respect to species composition and coverage of the herbaceous layer in vast areas of southern Kyrgyzstan's mountain pastures.In general,an intense grazing impact is clearly reflected by both species composition and structural variables of plant communities.The highly diverse and unique ecosystem is modified by an increasing utilization pressure.In order to maintain vital processes and functioning of this valuable ecosystem-in both economical and ecological terms-,it is indispensable to adopt appropriate pasture management strategies.
文摘In this work, the 'retention time gradient effect' of gradient GC columns is intensively studied to establish some equations and formulas for structure calculation of chromatographic columns. In addition, the relevant computer programs are designed.
