The Fringe Projection Profilometry(FPP)system with a single exposure time or a single projection intensity is limited by the dynamic range of the camera,which can lead to overexposure and underexposure of the image,re...The Fringe Projection Profilometry(FPP)system with a single exposure time or a single projection intensity is limited by the dynamic range of the camera,which can lead to overexposure and underexposure of the image,resulting in point cloud loss or reduced accuracy.To address this issue,unlike the pixel modulation method of projectors,we utilize the characteristics of color projectors where the intensity of the three-channel LED can be controlled independently.We propose a method for separating the projector's three-channel light intensity,combined with a color camera,to achieve single exposure and multi-intensity image acquisition.Further,the crosstalk coefficient is applied to predict the three-channel reflectance of the measured object.By integrating clustering and channel mapping,we establish a pixel-level mapping model between the projector's three-channel current and the camera's three-channel image intensity,which realizes the optimal projection current prediction and the high dynamic range(HDR)image acquisition.The proposed method allows for high-precision three-dimensional(3D)data acquisition of HDR scenes with a single exposure.The effectiveness of this method has been validated through experiments with standard planes and standard steps,showing a significant reduction in mean absolute error(44.6%)compared to existing singleexposure HDR methods.Additionally,the number of images required for acquisition is significantly reduced(by 70.8%)compared to multi-exposure fusion methods.This proposed method has great potential in various FPP-related fields.展开更多
A systematic understanding of the mechanism in the rectification and capacitance of nanochannels and their regulation with the electrolyte concentration and electrical bias is pivotal for its wide applications to nano...A systematic understanding of the mechanism in the rectification and capacitance of nanochannels and their regulation with the electrolyte concentration and electrical bias is pivotal for its wide applications to nanofluidic electronics,ion separation,energy storage,and molecule sensing.Single unipolar and bipolar cylindrical nanochannels through polymer film were fabricated using single ion bombardment and track etching.Cyclic voltammetry results show that the bipolar nanochannel switches from rectification to capacitance as the electrolyte concentration decreases.Electrochemical impedance spectroscopy revealed that the capacitive impedance fraction in the bipolar nanochannel is regulated by electrolyte concentration and voltage.The switch from rectification to capacitance in the polymer nanochannel is well explained through a fluidic p-n junction model with a variable ion depletion layer regulated by the applied bias voltage,which is supported by the multi-physics simulation using Poisson-Nernst-Planck and Navier-Stokes solution.This work provides a mechanistic insight into the ionic current rectification and ionic capacitance in complex ionic nanochannels and paves the way for biomimetic nanofluidic electronics design.展开更多
Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress i...Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress interference,which results in uneven fracture propagation. It is common practice to use “balls” to temporarily plug fractureopenings in order to lessen liquid intake and achieve uniform propagation in each cluster. In this study, a diameteroptimization model is introduced for these plugging balls based on a multi-cluster fracture propagationmodel and a perforation dynamic abrasion model. This approach relies on proper consideration of the multiphasenature of the considered problem and the interaction force between the involved fluid and solid phases. Accordingly,it can take into account the behavior of the gradually changing hole diameter due to proppant continuousperforation erosion. Moreover, it can provide useful information about the fluid-dynamic behavior of the consideredsystem before and after plugging. It is shown that when the diameter of the temporary plugging ball is1.2 times that of the perforation hole, the perforation holes of each cluster can be effectively blocked.展开更多
Evapotranspiration is an important parameter used to characterize the water cycle of ecosystems.To under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qing...Evapotranspiration is an important parameter used to characterize the water cycle of ecosystems.To under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qinghai-Tibet Plateau,an open-path eddy covariance system was set up to monitor the forest from November 2020 to October 2021 in a core area of the Three Parallel Rivers in the Qing-hai-Tibet Plateau.The results show that the evapotranspira-tion peaked daily,the maximum occurring between 11:00 and 15:00.Environmental factors had significant effects on evapotranspiration,among them,net radiation the greatest(R^(2)=0.487),and relative humidity the least(R^(2)=0.001).The energy flux varied considerably in different seasons and sensible heat flux accounted for the main part of turbulent energy.The energy balance ratio in the dormant season was less than that in the growing season,and there is an energy imbalance at the site on an annual time scale.展开更多
Background Weaning causes redox dyshomeostasis in piglets,which leads to hepatic oxidative damage.Microbederived antioxidants(MA)have great potential for anti-oxidat ion.This study aimed to investigate changes in hepa...Background Weaning causes redox dyshomeostasis in piglets,which leads to hepatic oxidative damage.Microbederived antioxidants(MA)have great potential for anti-oxidat ion.This study aimed to investigate changes in hepatic redox system,mitochondrial function and apoptosis after weaning,and effects of MA on growth performance and liver health in weaning piglets.Methods This study consisted of 2 experimets.In the both experiments,piglets were weaned at 21 days of age.In Exp.1,at 21(W0),22(W1),25(W4),28(W7),and 35(W14)days of age,6 piglets were slaughtered at each timepoint.In Exp.2,piglets were divided into 2 groups:one received MA gavage(MA)and the other received saline gavage(CON).At 25 days of age,6 piglets from each group were sacrificed.Results In Exp.1,weaning caused growth inhibition and liver developmental retardation from W0 to W4.The mRNA sequencing between W0 and W4 revealed that pathways related to"regulation of apoptotic process"and"reactive oxygen species metabolic process"were enriched.Further study showed that weaning led to higher hepatic content of reactive oxygen species(ROS),H_(2)O_(2) and O_(2)~-.Weaning enhanced mitochondrial fission and suppressed their fusion,activated mitophagy,thus triggering cell apoptosis.In Exp.2,MA improved growth performance of piglets with higher average daily gain(ADG)and average daily feed intake(ADFI).The hepatic ROS,as well as products of oxidative damage malonaldehyde(MDA)and 8-hydroxy-2'-deoxyguanosine(8-OHdG)in the MA group decreased significantly than that of the CON group.The MA elevated mitochondrial membrane potential,increased activity of mitochondrial respiratory chain complexes(MRC)ⅠandⅣ,enhanced mitochondrial fusion and reduced mitophagy thus decreasing cell apoptosis.Conclusions The present study showed that MA improved the growth performance of weaning piglets and reversed weaning-induced oxidative damage,mitochondrial dysfunction,and apoptosis.Our results suggested that MA had promising prospects for maintaining liver health in weaning piglets and provided a reference for studies of liver diseases in humans.展开更多
Casing deformation and frac-hit pose significant challenges to the development of deep shale gas in southern Sichuan Basin.By analyzing the mechanism and main control factors of casing deformation and frac-hit,two kin...Casing deformation and frac-hit pose significant challenges to the development of deep shale gas in southern Sichuan Basin.By analyzing the mechanism and main control factors of casing deformation and frac-hit,two kinds of risk assessment methods were defined,and the overall prevention and control concept and practice were formulated.The results show that initial stress,pore pressure,fault development and large scale fracturing in local block are the main factors leading to the deformation.The development of fracture through well group and uncontrolled fracturing fluid volume are the main factors leading to pressure channeling.Based on this,the risk classification technology of casing deformation and frac-hit is established,and the dual-optimal,dual-control concept and technology are formed.In terms of the prevention and control of casing deformation,the formation of small-diameter bridge plug fracturing,large section combined fracturing,glass beads cementing,singlewell staggered and platform straddle fracturing mode,dual-dimension controlled and lift fracturing,hyperbolic diagnosis,etc.Frac-hit prevention and control formed pump sequence optimization mode,physical and chemical temporary plugging and other methods.The above technology achieved casing deformation rate decreased from 50.4%to 25.4%,frac-hit rate decreased from 58.6%to 33.9%,and the average well kilometer EUR reached 0.52e0.7 million square meters,an increase of 7.7%compared with the previous research,with remarkable results.展开更多
文摘The Fringe Projection Profilometry(FPP)system with a single exposure time or a single projection intensity is limited by the dynamic range of the camera,which can lead to overexposure and underexposure of the image,resulting in point cloud loss or reduced accuracy.To address this issue,unlike the pixel modulation method of projectors,we utilize the characteristics of color projectors where the intensity of the three-channel LED can be controlled independently.We propose a method for separating the projector's three-channel light intensity,combined with a color camera,to achieve single exposure and multi-intensity image acquisition.Further,the crosstalk coefficient is applied to predict the three-channel reflectance of the measured object.By integrating clustering and channel mapping,we establish a pixel-level mapping model between the projector's three-channel current and the camera's three-channel image intensity,which realizes the optimal projection current prediction and the high dynamic range(HDR)image acquisition.The proposed method allows for high-precision three-dimensional(3D)data acquisition of HDR scenes with a single exposure.The effectiveness of this method has been validated through experiments with standard planes and standard steps,showing a significant reduction in mean absolute error(44.6%)compared to existing singleexposure HDR methods.Additionally,the number of images required for acquisition is significantly reduced(by 70.8%)compared to multi-exposure fusion methods.This proposed method has great potential in various FPP-related fields.
基金supported by the National Key R&D Program of China(Grant No.2021YFA1601400)the National Natural Science Foundation of China(Grant Nos.12241201,1197283,12375287,and U1632271).
文摘A systematic understanding of the mechanism in the rectification and capacitance of nanochannels and their regulation with the electrolyte concentration and electrical bias is pivotal for its wide applications to nanofluidic electronics,ion separation,energy storage,and molecule sensing.Single unipolar and bipolar cylindrical nanochannels through polymer film were fabricated using single ion bombardment and track etching.Cyclic voltammetry results show that the bipolar nanochannel switches from rectification to capacitance as the electrolyte concentration decreases.Electrochemical impedance spectroscopy revealed that the capacitive impedance fraction in the bipolar nanochannel is regulated by electrolyte concentration and voltage.The switch from rectification to capacitance in the polymer nanochannel is well explained through a fluidic p-n junction model with a variable ion depletion layer regulated by the applied bias voltage,which is supported by the multi-physics simulation using Poisson-Nernst-Planck and Navier-Stokes solution.This work provides a mechanistic insight into the ionic current rectification and ionic capacitance in complex ionic nanochannels and paves the way for biomimetic nanofluidic electronics design.
基金supported by the National Natural Science Foundation of China (No.U21B2071).
文摘Deep shale gas reserves that have been fractured typically have many relatively close perforation holes. Due to theproximity of each fracture during the formation of the fracture network, there is significant stress interference,which results in uneven fracture propagation. It is common practice to use “balls” to temporarily plug fractureopenings in order to lessen liquid intake and achieve uniform propagation in each cluster. In this study, a diameteroptimization model is introduced for these plugging balls based on a multi-cluster fracture propagationmodel and a perforation dynamic abrasion model. This approach relies on proper consideration of the multiphasenature of the considered problem and the interaction force between the involved fluid and solid phases. Accordingly,it can take into account the behavior of the gradually changing hole diameter due to proppant continuousperforation erosion. Moreover, it can provide useful information about the fluid-dynamic behavior of the consideredsystem before and after plugging. It is shown that when the diameter of the temporary plugging ball is1.2 times that of the perforation hole, the perforation holes of each cluster can be effectively blocked.
基金supported by the CAS"Light of West China"Program(2021XBZG-XBQNXZ-A-007)the National Natural Science Foundation of China(31971436)the State Key Laboratory of Cryospheric Science,Northwest Institute of Eco-Environment and Resources,Chinese Academy Sciences(SKLCS-OP-2021-06).
文摘Evapotranspiration is an important parameter used to characterize the water cycle of ecosystems.To under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qinghai-Tibet Plateau,an open-path eddy covariance system was set up to monitor the forest from November 2020 to October 2021 in a core area of the Three Parallel Rivers in the Qing-hai-Tibet Plateau.The results show that the evapotranspira-tion peaked daily,the maximum occurring between 11:00 and 15:00.Environmental factors had significant effects on evapotranspiration,among them,net radiation the greatest(R^(2)=0.487),and relative humidity the least(R^(2)=0.001).The energy flux varied considerably in different seasons and sensible heat flux accounted for the main part of turbulent energy.The energy balance ratio in the dormant season was less than that in the growing season,and there is an energy imbalance at the site on an annual time scale.
基金supported by the National Natural Science Foundation of China(Gant no.32272903)。
文摘Background Weaning causes redox dyshomeostasis in piglets,which leads to hepatic oxidative damage.Microbederived antioxidants(MA)have great potential for anti-oxidat ion.This study aimed to investigate changes in hepatic redox system,mitochondrial function and apoptosis after weaning,and effects of MA on growth performance and liver health in weaning piglets.Methods This study consisted of 2 experimets.In the both experiments,piglets were weaned at 21 days of age.In Exp.1,at 21(W0),22(W1),25(W4),28(W7),and 35(W14)days of age,6 piglets were slaughtered at each timepoint.In Exp.2,piglets were divided into 2 groups:one received MA gavage(MA)and the other received saline gavage(CON).At 25 days of age,6 piglets from each group were sacrificed.Results In Exp.1,weaning caused growth inhibition and liver developmental retardation from W0 to W4.The mRNA sequencing between W0 and W4 revealed that pathways related to"regulation of apoptotic process"and"reactive oxygen species metabolic process"were enriched.Further study showed that weaning led to higher hepatic content of reactive oxygen species(ROS),H_(2)O_(2) and O_(2)~-.Weaning enhanced mitochondrial fission and suppressed their fusion,activated mitophagy,thus triggering cell apoptosis.In Exp.2,MA improved growth performance of piglets with higher average daily gain(ADG)and average daily feed intake(ADFI).The hepatic ROS,as well as products of oxidative damage malonaldehyde(MDA)and 8-hydroxy-2'-deoxyguanosine(8-OHdG)in the MA group decreased significantly than that of the CON group.The MA elevated mitochondrial membrane potential,increased activity of mitochondrial respiratory chain complexes(MRC)ⅠandⅣ,enhanced mitochondrial fusion and reduced mitophagy thus decreasing cell apoptosis.Conclusions The present study showed that MA improved the growth performance of weaning piglets and reversed weaning-induced oxidative damage,mitochondrial dysfunction,and apoptosis.Our results suggested that MA had promising prospects for maintaining liver health in weaning piglets and provided a reference for studies of liver diseases in humans.
文摘Casing deformation and frac-hit pose significant challenges to the development of deep shale gas in southern Sichuan Basin.By analyzing the mechanism and main control factors of casing deformation and frac-hit,two kinds of risk assessment methods were defined,and the overall prevention and control concept and practice were formulated.The results show that initial stress,pore pressure,fault development and large scale fracturing in local block are the main factors leading to the deformation.The development of fracture through well group and uncontrolled fracturing fluid volume are the main factors leading to pressure channeling.Based on this,the risk classification technology of casing deformation and frac-hit is established,and the dual-optimal,dual-control concept and technology are formed.In terms of the prevention and control of casing deformation,the formation of small-diameter bridge plug fracturing,large section combined fracturing,glass beads cementing,singlewell staggered and platform straddle fracturing mode,dual-dimension controlled and lift fracturing,hyperbolic diagnosis,etc.Frac-hit prevention and control formed pump sequence optimization mode,physical and chemical temporary plugging and other methods.The above technology achieved casing deformation rate decreased from 50.4%to 25.4%,frac-hit rate decreased from 58.6%to 33.9%,and the average well kilometer EUR reached 0.52e0.7 million square meters,an increase of 7.7%compared with the previous research,with remarkable results.
