To meet the growing demand for socioeconomic development,a large amount of groundwater is extracted from confined aquifers worldwide.The North China Plain has experienced considerable groundwater depletion and subside...To meet the growing demand for socioeconomic development,a large amount of groundwater is extracted from confined aquifers worldwide.The North China Plain has experienced considerable groundwater depletion and subsidence during the past six decades.In this study,we use Sentinel-1A/B SAR images from 2015 to 2020 to map the ground subsidence of the Tianjin–Langfang area.Three subsiding zones centered at Guangyang,Wuqing–Bazhou,and Jinghai are identified with maximum subsidence rates of 98.1,121.8,and 104.7 mm/yr.Seasonal and long-term signals are separated from time series subsidence and hydraulic measurements using continuous wavelet transform to retrieve aquifer parameters.The long-term subsidence,which fits well with an exponential decaying model,remarkably slows down in our study area.The elastic skeletal storage coefficients range between 0.52×10−3 and 9.66×10−3.We then retrieve the spatial–temporal variations of total groundwater storage,recoverable groundwater storage,and irreversible groundwater storage.Groundwater storage depletion rates are apparently reducing,which benefits from the operation of the South-to-North Water Transfer Project and local groundwater management practices.展开更多
Multi-temporal InSAR technique can implement continuous earth surface deformation detection with long time scale and wide geographical coverage.In this paper,we first employ the Small Baseline Subset method to survey ...Multi-temporal InSAR technique can implement continuous earth surface deformation detection with long time scale and wide geographical coverage.In this paper,we first employ the Small Baseline Subset method to survey potential landslides in Guide County,Qinghai Province,which is identified as a loess landslide prone area for geological and climate conditions.Two anomalous deformation regions are detected by L-band Phased Array and L-band Synthetic Aperture Radar stacks.Then,qualitative and quantitative evaluations of the measuring points are given for understanding the distribution regularity of deformation.Finally,preliminary correlation between the time-series deformation and triggering factors is analyzed to explore the driving mechanism for landslide movement.The results demonstrate that L-band SAR has high potential in landslide monitoring applications and can be used as the basis for landslide recognizing,precursory information extracting,and early warning.展开更多
Palladium-based alloy is a kind of material with a high glass forming ability and can be easily formed into an amorphous state. After an annealing process, it can also be maintained at a crystallized state. To study t...Palladium-based alloy is a kind of material with a high glass forming ability and can be easily formed into an amorphous state. After an annealing process, it can also be maintained at a crystallized state. To study the thermal and electrical transport properties of crystallized palladium-based alloys, the steady-state T-type method, standard four-probe method, and AC heating-DC detecting T-type method were used to measure the thermal conductivity, electrical conductivity, and Seebeck coeffi- cient of crystallized Pd4oNiloCu3oP2o and Pd43Nilo- Cu27P2o alloys respectively. The results show that compared to amorphous samples, the thermal conductivity and electrical conductivity of crystallized palladium-based alloys are significantly higher, while the Seebeck coeffi- cient is lower. The ratio of crystallized and amorphous thermal conductivity is higher for Pd43Ni10Cu27P2o alloy fiber which has a higher glass forming ability, while the ratio of electronic thermal conductivity almost remains constant for both alloy fibers. The results also show that the slope of electrical resistivity to temperature is a function of elemental composition for crystallized quaternary palla- dium-based alloy fibers. The sensitivity of thermal conductivity and electrical conductivity to the composition is high, while the correlation between Seebeck coefficient and composition is relatively weak.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41702376,42001368 and 42174043).
文摘To meet the growing demand for socioeconomic development,a large amount of groundwater is extracted from confined aquifers worldwide.The North China Plain has experienced considerable groundwater depletion and subsidence during the past six decades.In this study,we use Sentinel-1A/B SAR images from 2015 to 2020 to map the ground subsidence of the Tianjin–Langfang area.Three subsiding zones centered at Guangyang,Wuqing–Bazhou,and Jinghai are identified with maximum subsidence rates of 98.1,121.8,and 104.7 mm/yr.Seasonal and long-term signals are separated from time series subsidence and hydraulic measurements using continuous wavelet transform to retrieve aquifer parameters.The long-term subsidence,which fits well with an exponential decaying model,remarkably slows down in our study area.The elastic skeletal storage coefficients range between 0.52×10−3 and 9.66×10−3.We then retrieve the spatial–temporal variations of total groundwater storage,recoverable groundwater storage,and irreversible groundwater storage.Groundwater storage depletion rates are apparently reducing,which benefits from the operation of the South-to-North Water Transfer Project and local groundwater management practices.
基金The authors would like to thank Japan Aerospace Exploration Agency(JAXA)for providing the PALSAR data sets via the ALOS-RA4 project(PI1440)This work was supported by the National Key Basic Research Program of China[grant number 2013CB733205].
文摘Multi-temporal InSAR technique can implement continuous earth surface deformation detection with long time scale and wide geographical coverage.In this paper,we first employ the Small Baseline Subset method to survey potential landslides in Guide County,Qinghai Province,which is identified as a loess landslide prone area for geological and climate conditions.Two anomalous deformation regions are detected by L-band Phased Array and L-band Synthetic Aperture Radar stacks.Then,qualitative and quantitative evaluations of the measuring points are given for understanding the distribution regularity of deformation.Finally,preliminary correlation between the time-series deformation and triggering factors is analyzed to explore the driving mechanism for landslide movement.The results demonstrate that L-band SAR has high potential in landslide monitoring applications and can be used as the basis for landslide recognizing,precursory information extracting,and early warning.
文摘Palladium-based alloy is a kind of material with a high glass forming ability and can be easily formed into an amorphous state. After an annealing process, it can also be maintained at a crystallized state. To study the thermal and electrical transport properties of crystallized palladium-based alloys, the steady-state T-type method, standard four-probe method, and AC heating-DC detecting T-type method were used to measure the thermal conductivity, electrical conductivity, and Seebeck coeffi- cient of crystallized Pd4oNiloCu3oP2o and Pd43Nilo- Cu27P2o alloys respectively. The results show that compared to amorphous samples, the thermal conductivity and electrical conductivity of crystallized palladium-based alloys are significantly higher, while the Seebeck coeffi- cient is lower. The ratio of crystallized and amorphous thermal conductivity is higher for Pd43Ni10Cu27P2o alloy fiber which has a higher glass forming ability, while the ratio of electronic thermal conductivity almost remains constant for both alloy fibers. The results also show that the slope of electrical resistivity to temperature is a function of elemental composition for crystallized quaternary palla- dium-based alloy fibers. The sensitivity of thermal conductivity and electrical conductivity to the composition is high, while the correlation between Seebeck coefficient and composition is relatively weak.
