The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallo...The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we di展开更多
This paper established a numerical model for a solid oxide fuel cell （SOFC） button cell, focusing on the effects of finger-like channels on the gas transport process in the anode support. The current densities of ch...This paper established a numerical model for a solid oxide fuel cell （SOFC） button cell, focusing on the effects of finger-like channels on the gas transport process in the anode support. The current densities of channelled button cell and un-channelled button cell are compared at different operating temperature and voltage with H2 as the fuel. The H2 transport is discussed in detail, such as the mole fraction distribution of H2 in the porous layer, the diffusion flux and convective flux of Ha. It is found that the performance of SOFC can be improved by 2.60 % at 800 ~C, 0.5 V, com- pared with un-channelled SOFC due to the improved gas transport by the finger-like channels. Then, the model is further extended to study 2D-planar SOFC fuelled with syngas. The mole fraction gradients of H2, CO, CH4 and CO are all substantially reduced by the finger-like channels compared to un-channelled planar cell. It is found that the SOFC performance is improved by 5.93 % at 800℃, 0.5 V, when syngas fuel is used. The present study clearly demonstrated that the use of finger-like channels in the anode support is effective in improving the gas transport and the SOFC performance. The present model can be employed for subsequent optimization of the channel configuration for further performance improvement.展开更多
There is not much correlation between sand content and P-wave impedance in faulted basins,and the prediction results cannot be guaranteed. Due to sedimentary facies control,there is inconsistency between sand content ...There is not much correlation between sand content and P-wave impedance in faulted basins,and the prediction results cannot be guaranteed. Due to sedimentary facies control,there is inconsistency between sand content and low frequency trend of P-wave impedance,causing problems for seismic inversion modeling,which directly affects final seismic inversion results. The acoustic impedance increases with burial depth. When the same layers of sand and shale formation endure different compaction,the acoustic impedance values will be different. Therefore,The seismic inversion modeling of faulted basin is different from that of conventional basins.The authors built an inversion model using uncompact sandstone percentage,directly compensating for the low frequency trend of the inversion model. In addition,the model's intermediate frequency is similar to P-wave impedance,ensuring that the inversion results are converged correctly. The final results of the inversion can be used directly as sandstone percentage. The aforementioned method was applied to Liaohe Beach in the Bijialing region and obtained optimistic lithology inversion effects: the results were correlated well with the depositional facies map and with lithology in the well borehole. The inversion results can be used to define the sand body horizontally and can separate sand bodies vertically,which is very difficult on conventional seismic section.Therefore the inversion results played an important role in reservoir prediction.展开更多
Numerical back analysis is a valuable tool available to rock mechanics researchers and practitioners.Recent studies related to back analysis methods focused primarily on applications of increasingly sophisticated opti...Numerical back analysis is a valuable tool available to rock mechanics researchers and practitioners.Recent studies related to back analysis methods focused primarily on applications of increasingly sophisticated optimization algorithms(primarily machine learning algorithms)to rock mechanics problems.These methods have typically been applied to relatively simple problems;however,more complex back analyses continue to be conducted primarily through ad hoc manual trial-and-error processes.This paper provides a review of the basic concepts and recent developments in the field of numerical back analysis for rock mechanics,as well as some discussion of the relationship between back analysis and more broadly established frameworks for numerical modelling.The challenges of flexible constraints,non-uniqueness,material model limitations,and disparate data sources are considered,and representative case studies are presented to illustrate their impacts on back analyses.The role of back analysis(or“model calibration”)in bonded particle modelling(BPM),bonded block modelling(BBM),and synthetic rock mass(SRM)modelling is also considered,and suggestions are made for further studies on this topic.展开更多
Beijing often suffers under heavy smog.During such events which occur mostly in autumn and winter,people are desperate for fresh air.The formation of heavy smog is due to foremost human induced air pollution,but geogr...Beijing often suffers under heavy smog.During such events which occur mostly in autumn and winter,people are desperate for fresh air.The formation of heavy smog is due to foremost human induced air pollution,but geographic and meteorological conditions,especially below a surface inversion,play an important role.We propose to destroy the inversion by pumping air from above the inversion layer to the surface layer to alleviate the severity of the smog.While long-term air quality improvement depends on the reduction of air pollution emission,air pumping may provide relief in the interim for the Beijing citizens.We estimate that an air pumping at a rate 2×10~7m^3s^(–1)can lead to significantly improved air quality in Beijing,due to(1)direct clean air input;(2)increased instability and vertical mixing and(3)a positive radiation-mixing feedback.The pumping requires an energy input of 10 GW,comparable with the energy consumption in Beijing for air conditioning in summer.We propose to use wind energy from Inner Mongolia for the pumping,which has currently an installed wind energy capacity of 70GW.展开更多
基金jointly supported by the National Key R&D Program of China(Grant No.2016YFC0600201)China Geological Survey project(Grant Nos.DD20190012,DD20160082)the National Natural Science Foundation of China(Grant Nos.92062108,41630320,41574133)。
文摘The Zhuxi tungsten deposit in Jiangxi Province,South China,contains a total W reserve of about 2.86 Mt at an average grade of 0.54 wt%WO3,representing the largest W deposit in the world.Numerous studies on the metallogeny of the deposit have included its timing,the ore-controlling structures and sedimentary host rocks and their implications for mineral exploration.However,the deep nappe structural style of Taqian-Fuchun metallogenic belt that hosts the W deposit,and the spatial shape and scale of deeply concealed intrusions and their sedimentary host rocks are still poorly defined,which seriously restricts the discovery of new deposits at depth and in surrounding areas of the W deposit.Modern 3 D geological modeling is an important tool for the exploration of concealed orebodies,especially in brownfield environments.There are obvious density contrast and weak magnetic contrast in the ore-controlling strata and granite at the periphery of the deposit,which lays a physical foundation for solving the 3 D spatial problems of the ore-controlling geological body in the deep part of the study area through gravity and magnetic modeling.Gravity data(1:50000)and aeromagnetic data(1:50000)from the latest geophysical surveys of 2016-2018 have been used,firstly,to carry out a potential field separation to obtain residual anomalies for gravity and magnetic interactive inversion.Then,on the basis of the analysis of the relationship between physical properties and lithology,under the constraints of surface geology and borehole data,human-computer interactive gravity and magnetic inversion for 18 cross-sections were completed.Finally,the 3 D geological model of the Zhuxi tungsten deposit and its periphery have been established through these 18 sections,and the spatial shape of the intrusions and strata with a depth of 5 km underground were obtained,initially realizing―transparency‖for ore-controlling bodies.According the analysis of the geophysical,geochemical,and geological characteristics of the Zhuxi tungsten deposit,we di
基金supported by a Grant(PolyU 152127/14E) from Research Grant Council,University Grants Committee,Hong Kong SAR
文摘This paper established a numerical model for a solid oxide fuel cell （SOFC） button cell, focusing on the effects of finger-like channels on the gas transport process in the anode support. The current densities of channelled button cell and un-channelled button cell are compared at different operating temperature and voltage with H2 as the fuel. The H2 transport is discussed in detail, such as the mole fraction distribution of H2 in the porous layer, the diffusion flux and convective flux of Ha. It is found that the performance of SOFC can be improved by 2.60 % at 800 ~C, 0.5 V, com- pared with un-channelled SOFC due to the improved gas transport by the finger-like channels. Then, the model is further extended to study 2D-planar SOFC fuelled with syngas. The mole fraction gradients of H2, CO, CH4 and CO are all substantially reduced by the finger-like channels compared to un-channelled planar cell. It is found that the SOFC performance is improved by 5.93 % at 800℃, 0.5 V, when syngas fuel is used. The present study clearly demonstrated that the use of finger-like channels in the anode support is effective in improving the gas transport and the SOFC performance. The present model can be employed for subsequent optimization of the channel configuration for further performance improvement.
基金Supported by Project of National Natural Science Foundation(No.41430322)
文摘There is not much correlation between sand content and P-wave impedance in faulted basins,and the prediction results cannot be guaranteed. Due to sedimentary facies control,there is inconsistency between sand content and low frequency trend of P-wave impedance,causing problems for seismic inversion modeling,which directly affects final seismic inversion results. The acoustic impedance increases with burial depth. When the same layers of sand and shale formation endure different compaction,the acoustic impedance values will be different. Therefore,The seismic inversion modeling of faulted basin is different from that of conventional basins.The authors built an inversion model using uncompact sandstone percentage,directly compensating for the low frequency trend of the inversion model. In addition,the model's intermediate frequency is similar to P-wave impedance,ensuring that the inversion results are converged correctly. The final results of the inversion can be used directly as sandstone percentage. The aforementioned method was applied to Liaohe Beach in the Bijialing region and obtained optimistic lithology inversion effects: the results were correlated well with the depositional facies map and with lithology in the well borehole. The inversion results can be used to define the sand body horizontally and can separate sand bodies vertically,which is very difficult on conventional seismic section.Therefore the inversion results played an important role in reservoir prediction.
基金funding support from National Institute for Occupational Safety and Health(NIOSH)(Grant No.200-2016-90154)。
文摘Numerical back analysis is a valuable tool available to rock mechanics researchers and practitioners.Recent studies related to back analysis methods focused primarily on applications of increasingly sophisticated optimization algorithms(primarily machine learning algorithms)to rock mechanics problems.These methods have typically been applied to relatively simple problems;however,more complex back analyses continue to be conducted primarily through ad hoc manual trial-and-error processes.This paper provides a review of the basic concepts and recent developments in the field of numerical back analysis for rock mechanics,as well as some discussion of the relationship between back analysis and more broadly established frameworks for numerical modelling.The challenges of flexible constraints,non-uniqueness,material model limitations,and disparate data sources are considered,and representative case studies are presented to illustrate their impacts on back analyses.The role of back analysis(or“model calibration”)in bonded particle modelling(BPM),bonded block modelling(BBM),and synthetic rock mass(SRM)modelling is also considered,and suggestions are made for further studies on this topic.
基金supported by the National Natural Science Foundation of China(Grant No.91537211)
文摘Beijing often suffers under heavy smog.During such events which occur mostly in autumn and winter,people are desperate for fresh air.The formation of heavy smog is due to foremost human induced air pollution,but geographic and meteorological conditions,especially below a surface inversion,play an important role.We propose to destroy the inversion by pumping air from above the inversion layer to the surface layer to alleviate the severity of the smog.While long-term air quality improvement depends on the reduction of air pollution emission,air pumping may provide relief in the interim for the Beijing citizens.We estimate that an air pumping at a rate 2×10~7m^3s^(–1)can lead to significantly improved air quality in Beijing,due to(1)direct clean air input;(2)increased instability and vertical mixing and(3)a positive radiation-mixing feedback.The pumping requires an energy input of 10 GW,comparable with the energy consumption in Beijing for air conditioning in summer.We propose to use wind energy from Inner Mongolia for the pumping,which has currently an installed wind energy capacity of 70GW.
