One-dimensional(1D)micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors.However,in the axial direction of micro/nanowires,the carriers can tra...One-dimensional(1D)micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors.However,in the axial direction of micro/nanowires,the carriers can transport freely driven by an external electric field,which usually produces large dark current and low detectivity.Here,an UV photodetector built from three cross-intersecting ZnO microwires with double homo-interfaces is demonstrated by the chemical vapor deposition and physical transfer techniques.Compared with the reference device without interface,the dark current of this ZnO double-interface photodetector is significantly reduced by nearly 5 orders of magnitude,while the responsivity decreases slightly,thereby greatly improving the normalized photocurrent-to-dark current ratio.In addition,ZnO double-interface photodetector exhibits a much faster response speed(~0.65 s)than the no-interface device(~95 s).The improved performance is attributed to the potential barriers at the microwire-microwire homo-interfaces,which can regulate the carrier transport.Our findings in this work provide a promising approach for the design and development of high-performance photodetectors.展开更多
To study the seepage and deformation characteristics of coal at high temperatures,coal samples from six different regions were selected and subjected to computed tomography(CT)scanning studies.In conjunction with ANSY...To study the seepage and deformation characteristics of coal at high temperatures,coal samples from six different regions were selected and subjected to computed tomography(CT)scanning studies.In conjunction with ANSYS software,3 D reconstruction of CT images was used for the establishment of fluidsolid conjugate heat transfer model and coal thermal deformation model based on the microstructures of coal.In addition,the structure of coal was studied in 2 D and 3 D perspectives,followed by the analysis of seepage and deformation characteristics of coal at high temperatures.The results of this study indicated that porosity positively correlated with the fractal dimension,and the connectivity and seepage performances were roughly identical from 2 D and 3 D perspectives.As the porosity increased,the fractal dimension of coal samples became larger and the pore-fracture structures became more complex.As a result,the permeability of coal samples decreased.In the meantime,fluid was fully heated,generating high-temperature water at outlet.However,when the porosity was low,the outlet temperature was very high.The average deformation of coal skeleton with different pore-fracture structures at high temperatures showed a trend of initial increase and subsequent decrease with the increase of porosity and fractal dimension.The maximum deformation of coal skeleton positively correlated with connectivity but negatively correlated with the fractal dimension.展开更多
Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for...Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for a longer time in the lung.Recent studies have found that they can be transported into various extra-pulmonary organs by crossing the air-blood barrier(ABB).Therefore,to understand the adverse effects of UFPs,it is crucial to thoroughly investigate their bio-distribution and clearance pathways in vivo after inhalation,as well as their toxicological mechanisms.This review highlights emerging evidence on the bio-distribution of UFPs in pulmonary and extra-pulmonary organs.It explores how UFPs penetrate the ABB,the blood-brain barrier(BBB),and the placental barrier(PB)and subsequently undergo clearance by the liver,kidney,or intestine.In addition,the potential underlying toxicological mechanisms of UFPs are summarized,providing fundamental insights into how UFPs induce adverse health effects.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62074148,61875194,11727902,12074372,11774341,11974344,61975204,and 11804335)the National Ten Thousand Talent Program for Young Topnotch Talents,the Key Research and Development Program of Changchun City(Grant No.21ZY05)+2 种基金the 100 Talents Program of the Chinese Academy of Sciences,Youth Innovation Promotion Association,CAS(Grant No.2020225)Jilin Province Science Fund(Grant No.20210101145JC)XuGuang Talents Plan of CIOMP。
文摘One-dimensional(1D)micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors.However,in the axial direction of micro/nanowires,the carriers can transport freely driven by an external electric field,which usually produces large dark current and low detectivity.Here,an UV photodetector built from three cross-intersecting ZnO microwires with double homo-interfaces is demonstrated by the chemical vapor deposition and physical transfer techniques.Compared with the reference device without interface,the dark current of this ZnO double-interface photodetector is significantly reduced by nearly 5 orders of magnitude,while the responsivity decreases slightly,thereby greatly improving the normalized photocurrent-to-dark current ratio.In addition,ZnO double-interface photodetector exhibits a much faster response speed(~0.65 s)than the no-interface device(~95 s).The improved performance is attributed to the potential barriers at the microwire-microwire homo-interfaces,which can regulate the carrier transport.Our findings in this work provide a promising approach for the design and development of high-performance photodetectors.
基金supported by the National Natural Science Foundation of China(Project Nos.51934004,51674158,51574158,and 51474106)the Major Program of Shandong Province Natural Science Foundation(ZR2018ZA0602)+2 种基金the Taishan Scholar Talent Team Support Plan for Advantaged&Unique Discipline Areasthe Science and technology support plan for Youth Innovation of colleges and universities in Shandong Province(2019KJH006)the special funds for Taishan scholar project(TS20190935)。
文摘To study the seepage and deformation characteristics of coal at high temperatures,coal samples from six different regions were selected and subjected to computed tomography(CT)scanning studies.In conjunction with ANSYS software,3 D reconstruction of CT images was used for the establishment of fluidsolid conjugate heat transfer model and coal thermal deformation model based on the microstructures of coal.In addition,the structure of coal was studied in 2 D and 3 D perspectives,followed by the analysis of seepage and deformation characteristics of coal at high temperatures.The results of this study indicated that porosity positively correlated with the fractal dimension,and the connectivity and seepage performances were roughly identical from 2 D and 3 D perspectives.As the porosity increased,the fractal dimension of coal samples became larger and the pore-fracture structures became more complex.As a result,the permeability of coal samples decreased.In the meantime,fluid was fully heated,generating high-temperature water at outlet.However,when the porosity was low,the outlet temperature was very high.The average deformation of coal skeleton with different pore-fracture structures at high temperatures showed a trend of initial increase and subsequent decrease with the increase of porosity and fractal dimension.The maximum deformation of coal skeleton positively correlated with connectivity but negatively correlated with the fractal dimension.
基金funded by the National Key Research and Development Program of China(2019YFC1804503 to YX)the National Natural Science Foundation of China(82003414 to YX).
文摘Ambient particles severely threaten human health worldwide.Compared to larger particles,ultrafine particles(UFPs)are highly concentrated in ambient environments,have a larger specific surface area,and are retained for a longer time in the lung.Recent studies have found that they can be transported into various extra-pulmonary organs by crossing the air-blood barrier(ABB).Therefore,to understand the adverse effects of UFPs,it is crucial to thoroughly investigate their bio-distribution and clearance pathways in vivo after inhalation,as well as their toxicological mechanisms.This review highlights emerging evidence on the bio-distribution of UFPs in pulmonary and extra-pulmonary organs.It explores how UFPs penetrate the ABB,the blood-brain barrier(BBB),and the placental barrier(PB)and subsequently undergo clearance by the liver,kidney,or intestine.In addition,the potential underlying toxicological mechanisms of UFPs are summarized,providing fundamental insights into how UFPs induce adverse health effects.