Joint inversion based on a correlation constraint utilizes a linear correlation function as a structural constraint.The linear correlation function contains a denominator,which may result in a singularity as the objec...Joint inversion based on a correlation constraint utilizes a linear correlation function as a structural constraint.The linear correlation function contains a denominator,which may result in a singularity as the objective function is optimized,leading to an unstable inversion calculation.To improve the robustness of this calculation,this paper proposes a new method in which a sinusoidal correlation function is employed as the structural constraint for joint inversion instead of the conventional linear correlation function.This structural constraint does not contain a denominator,thereby preventing a singularity.Compared with the joint inversion method based on a cross-gradient constraint,the joint inversion method based on a sinusoidal correlation constraint exhibits good performance.An application to actual data demonstrates that this method can process real data.展开更多
Carbon-bearing stratum normally features low resistance and high polarization.If the lithostratigraphy of the exploration area contains large amounts of carbon,the induced polarization anomaly caused by metal sulfide ...Carbon-bearing stratum normally features low resistance and high polarization.If the lithostratigraphy of the exploration area contains large amounts of carbon,the induced polarization anomaly caused by metal sulfide ore bodies will be inundated by the high polarization of carbon-containing wall rock.In this work,we adopted time-domain induced polarization(TDIP)and controlled-source audio-frequency magnetotellurics(CSAMT)on deep prospecting of the carbon-bearing stratum of the Ar Horqin Banner,Inner Mongolia.The underground medium is divided into target geologic bodies according to the geological information within the known exploration line borehole,and the physical properties of various target geologic bodies are calculated using weighted averages to build a geologic-geophysical model that can fit the observation data.Consequently,we can determine the range and morphological characteristics of the electrical properties of the ore-bearing geologic bodies in the inversion results in the study area.Then we can use the characteristics summarized from the known exploration line to interpret unknown exploration line.Results indicated that,when the diff erence in physical properties between the ore body and interference wall rock is not clear,the geologic body can be classifi ed via the paragenetic(associated)assemblage relations of the underground medium.Geological interpretation is guided by the comprehensive physical properties of ore-bearing geologic bodies to avoid interferences.展开更多
In this study,Shengli fault depression,Tangyuan fault basin,and northern Songliao Basin in Yitong‒Yilan fault zone of Heilongjiang province are considered the research areas for geothermal anomaly.Based on the tempera...In this study,Shengli fault depression,Tangyuan fault basin,and northern Songliao Basin in Yitong‒Yilan fault zone of Heilongjiang province are considered the research areas for geothermal anomaly.Based on the temperature of the deep thermal reservoir,the hydrothermal fl uid channel,caprock thickness,and the mode of heat transfer,which are the main factors controlling the geothermal reservoir formation,we examined geothermal resource system of the underground HDR in this area.First,we inversed the aeromagnetic data,calculated the Curie isotherm depth,analyzed the geothermal distribution characteristics,and estimated the temperature of the deep heat source.Second,we applied the controlled source audio frequency magnetotelluric(CSAMT)and magnetotelluric(MT)methods to obtain the deep electrical structure of the study area.We determined the thickness of the caprock and the hydrothermal fluid channel.Finally,we obtained the borehole geothermal steady-state temperature measurement data and water sample chemical analysis data from the logging temperature curves of 24 wells to infer the mode of heat transfer.Based on the results,we built a model of the geothermal system of the sedimentary basin in this area.The results show that the depth of Curie isotherm in the study area is 17–39 km.The resistivity of sedimentary caprock in the north of Songliao basin is low,and there exists a deep heat source,which is mainly thermal convection.In contrast,in Shengli and Tangyuan fault basins,heat conduction is dominant.Based on the geothermal system model,we conclude that the area from Daqing to Lindian in Songliao basin has a thermal-convection-dominated sedimentary basin geothermal system.Heat exchange is realized by the upwelling of mantle-derived thermal materials through fracture channels.The thick sedimentary caprock reduces the heat loss.It can be a target for sustainable development and utilization of HDR.展开更多
Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decreas...Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decrease the proliferation of astroglial cells and therefore reduce excessive gliosis and glial scar formation after focal ischemia.Methods:Cerebral infarction model was induced by photothrombosis method.Rats were examined using MRI,and lesion volumes were estimated on day 3 post-infarction.The expression of glial fibrillary acidic protein(GFAP) and proliferating cell nuclear antigen(PCNA) was observed by immunofluorescence staining.Protein levels for GFAP,PCNA,Cyclin A and Cyclin B1 were determined by Western blot analysis from the ischemic and sham animals sacrificed at 3,7,30 days after operation.Results:Cell cycle inhibitor olomoucine significantly suppressed GFAP and PCNA expression and reduced lesion volume after cerebral ischemia.In parallel studies,we found dense astroglial scar in boundary zone of vehicle-treated rats at 7 and 30 days.Olomoucine can markedly attenuate astroglial scar formation.Western blot analysis showed increased protein levels of GFAP,PCNA,Cyclin A and Cyclin B1 after ischemia,which was reduced by olomoucine treatment.Conclusion: Our results suggested that astroglial activation,proliferation and subsequently astroglial scar formation could be partially inhibited by regulation of cell cycle.Cell cycle modulation thereby provides a potential promising strategy to treat cerebral ischemia.展开更多
基金supported by the National Key Research and Development Project of China(No:2017YFC0602201)
文摘Joint inversion based on a correlation constraint utilizes a linear correlation function as a structural constraint.The linear correlation function contains a denominator,which may result in a singularity as the objective function is optimized,leading to an unstable inversion calculation.To improve the robustness of this calculation,this paper proposes a new method in which a sinusoidal correlation function is employed as the structural constraint for joint inversion instead of the conventional linear correlation function.This structural constraint does not contain a denominator,thereby preventing a singularity.Compared with the joint inversion method based on a cross-gradient constraint,the joint inversion method based on a sinusoidal correlation constraint exhibits good performance.An application to actual data demonstrates that this method can process real data.
基金The Research is funded by Comprehensive Intelligent Mapping System and Application of Geological Survey(DD20190415)Exploration and Development Tracking and Result Integration of Energy and Important Mineral Resources(DD20190457)Resource Assessment and Prediction for Main Tectonic Metallogenetic Domains in the World(DD20190459).
文摘Carbon-bearing stratum normally features low resistance and high polarization.If the lithostratigraphy of the exploration area contains large amounts of carbon,the induced polarization anomaly caused by metal sulfide ore bodies will be inundated by the high polarization of carbon-containing wall rock.In this work,we adopted time-domain induced polarization(TDIP)and controlled-source audio-frequency magnetotellurics(CSAMT)on deep prospecting of the carbon-bearing stratum of the Ar Horqin Banner,Inner Mongolia.The underground medium is divided into target geologic bodies according to the geological information within the known exploration line borehole,and the physical properties of various target geologic bodies are calculated using weighted averages to build a geologic-geophysical model that can fit the observation data.Consequently,we can determine the range and morphological characteristics of the electrical properties of the ore-bearing geologic bodies in the inversion results in the study area.Then we can use the characteristics summarized from the known exploration line to interpret unknown exploration line.Results indicated that,when the diff erence in physical properties between the ore body and interference wall rock is not clear,the geologic body can be classifi ed via the paragenetic(associated)assemblage relations of the underground medium.Geological interpretation is guided by the comprehensive physical properties of ore-bearing geologic bodies to avoid interferences.
基金the State Key Research and Development Plan.Comprehensive Airborne Geophysics Exploration System Integration and Technical Demonstration(No.2017YFC0602201)。
文摘In this study,Shengli fault depression,Tangyuan fault basin,and northern Songliao Basin in Yitong‒Yilan fault zone of Heilongjiang province are considered the research areas for geothermal anomaly.Based on the temperature of the deep thermal reservoir,the hydrothermal fl uid channel,caprock thickness,and the mode of heat transfer,which are the main factors controlling the geothermal reservoir formation,we examined geothermal resource system of the underground HDR in this area.First,we inversed the aeromagnetic data,calculated the Curie isotherm depth,analyzed the geothermal distribution characteristics,and estimated the temperature of the deep heat source.Second,we applied the controlled source audio frequency magnetotelluric(CSAMT)and magnetotelluric(MT)methods to obtain the deep electrical structure of the study area.We determined the thickness of the caprock and the hydrothermal fluid channel.Finally,we obtained the borehole geothermal steady-state temperature measurement data and water sample chemical analysis data from the logging temperature curves of 24 wells to infer the mode of heat transfer.Based on the results,we built a model of the geothermal system of the sedimentary basin in this area.The results show that the depth of Curie isotherm in the study area is 17–39 km.The resistivity of sedimentary caprock in the north of Songliao basin is low,and there exists a deep heat source,which is mainly thermal convection.In contrast,in Shengli and Tangyuan fault basins,heat conduction is dominant.Based on the geothermal system model,we conclude that the area from Daqing to Lindian in Songliao basin has a thermal-convection-dominated sedimentary basin geothermal system.Heat exchange is realized by the upwelling of mantle-derived thermal materials through fracture channels.The thick sedimentary caprock reduces the heat loss.It can be a target for sustainable development and utilization of HDR.
基金This study was supported by a grant from the National Nature Science Foundation of China(No.30230140,30400142)
文摘Background:Astrocytes become reactive following many types of CNS injuries.Excessive astrogliosis is detrimental and contributes to neuronal damage.We sought to determine whether inhibition of cell cycle could decrease the proliferation of astroglial cells and therefore reduce excessive gliosis and glial scar formation after focal ischemia.Methods:Cerebral infarction model was induced by photothrombosis method.Rats were examined using MRI,and lesion volumes were estimated on day 3 post-infarction.The expression of glial fibrillary acidic protein(GFAP) and proliferating cell nuclear antigen(PCNA) was observed by immunofluorescence staining.Protein levels for GFAP,PCNA,Cyclin A and Cyclin B1 were determined by Western blot analysis from the ischemic and sham animals sacrificed at 3,7,30 days after operation.Results:Cell cycle inhibitor olomoucine significantly suppressed GFAP and PCNA expression and reduced lesion volume after cerebral ischemia.In parallel studies,we found dense astroglial scar in boundary zone of vehicle-treated rats at 7 and 30 days.Olomoucine can markedly attenuate astroglial scar formation.Western blot analysis showed increased protein levels of GFAP,PCNA,Cyclin A and Cyclin B1 after ischemia,which was reduced by olomoucine treatment.Conclusion: Our results suggested that astroglial activation,proliferation and subsequently astroglial scar formation could be partially inhibited by regulation of cell cycle.Cell cycle modulation thereby provides a potential promising strategy to treat cerebral ischemia.
