Since 3D printed hard materials could match the shape of bone,cell survival and fate determination towards osteoblasts in such materials have become a popular research target.In this study,a scaffold of hardmaterial f...Since 3D printed hard materials could match the shape of bone,cell survival and fate determination towards osteoblasts in such materials have become a popular research target.In this study,a scaffold of hardmaterial for 3D fabrication was designed to regulate developmental signal(Notch)transduction guiding osteoblast differentiation.We established a polycaprolactone(PCL)and cell-integrated 3D printing system(PCI3D)to reciprocally print the beams of PCL and cell-laden hydrogel for a module.This PCI3D module holds good cell viability of over 87%,whereas cells show about sixfold proliferation in a 7-day culture.The osteocytic MLO-Y4 was engineered to overexpress Notch ligand Dll4,making up 25%after mixing with 75%stromal cells in the PCI3D module.Osteocytic Dll4,unlike other delta-like family members such as Dll1 or Dll3,promotes osteoblast differentiation and themineralization of primary mouse and a cell line of bone marrow stromal cells when cultured in a PCI3D module for up to 28 days.Mechanistically,osteocytic Dll4 could not promote osteogenic differentiation of the primary bone marrow stromal cells(BMSCs)after conditional deletion of the Notch transcription factor RBPjκby Cre recombinase.These data indicate that osteocytic Dll4 activates RBPjκ-dependent canonical Notch signaling in BMSCs for their oriented differentiation towards osteoblasts.Additionally,osteocytic Dll4 holds a great potential for angiogenesis in human umbilical vein endothelial cells within modules.Our study reveals that osteocytic Dll4 could be the osteogenic niche determining cell fate towards osteoblasts.This will open a new avenue to overcome the current limitation of poor cell viability and low bioactivity of traditional orthopedic implants.展开更多
Gibberellin(GA)functions in plant growth and development.However,genes involved in the biosynthesis and regulation of GA in crop plants are poorly understood.We isolated the mutant gad5-1(GAAssociated Dwarf 5),charact...Gibberellin(GA)functions in plant growth and development.However,genes involved in the biosynthesis and regulation of GA in crop plants are poorly understood.We isolated the mutant gad5-1(GAAssociated Dwarf 5),characterized by dwarfing,short internodes,and dark green and short leaves.Map-based gene cloning and allelic verification confirmed that ZmGAD5 encodes ent-kaurenoic acid oxidase(KAO),which catalyzes KA(ent-kaurenoic acid)to GA12 conversion during GA biosynthesis in maize.ZmGAD5 is localized to the endoplasmic reticulum and is present in multiple maize organs.In gad5-1,the expression of ZmGAD5 is severely reduced,and the levels of the direct substrate of KAO,KA,is increased,leading to a reduction in GA content.The abnormal phenotype of gad5-1 was restored by exogenous application of GA3.The biomass,plant height,and levels of GA12 and GA3 in transgenic Arabidopsis overexpressing ZmGAD5 were increased in comparison with the corresponding controls Col-0.These findings deepen our understanding of genes involved in GA biosynthesis,and could lead to the development of maize lines with improved architecture and higher planting-density tolerance.展开更多
Reactive oxygen species(ROS)are produced as undesirable by-products of metabolism in various cellular compartments,especially in response to unfavorable environmental conditions,throughout the life cycle of plants.Str...Reactive oxygen species(ROS)are produced as undesirable by-products of metabolism in various cellular compartments,especially in response to unfavorable environmental conditions,throughout the life cycle of plants.Stressinduced ROS production disrupts normal cellular function and leads to oxidative damage.To cope with excessive ROS,plants are equipped with a sophisticated antioxidative defense system consisting of enzymatic and non-enzymatic components that scavenge ROS or inhibit their harmful effects on biomolecules.Nonetheless,when maintained at relatively low levels,ROS act as signaling molecules that regulate plant growth,development,and adaptation to adverse conditions.Here,we provide an overview of current approaches for detecting ROS.We also discuss recent advances in understanding ROS signaling,ROS metabolism,and the roles of ROS in plant growth and responses to various abiotic stresses.展开更多
To harness the rich solar energy resources in Xinjiang Region of Northwest China,this study tries to address the issue of lack of downward surface shortwave radiation(DSSR)observations and the need to improve the accu...To harness the rich solar energy resources in Xinjiang Region of Northwest China,this study tries to address the issue of lack of downward surface shortwave radiation(DSSR)observations and the need to improve the accuracy of satellite retrieval and numerical simulation of DSSR under varied sky and meteorological conditions.(1)A two-layer aerosol model specific to Xinjiang was developed to capture the vertical distributions of aerosols based on multiple data sources including lidar,GPS sounding,ground meteorological observations,and profiles from the ECMWF reanalysis version 5(ERA5)data.The results show that the ERA5/PBLH(planetary boundary layer height)and ERA5/ALH(aerosol layer height)could be used to establish the two-layer aerosol model and characterize the vertical distribution of aerosols in Xinjiang Region.(2)Using the Santa Barbara Discrete Atmospheric Radiative Transfer(SBDART)model,a localized inverse model of clear-sky DSSR was established.After parameter adjustment and using the optimal combination of input parameters for DSSR simulation together with the two-layer aerosol model,the model-simulated DSSR(DSSRSBD)under clear-sky conditions improved significantly compared to the initial results,with all fitting indices greatly improved.(3)In addition,the study demonstrated that the impact of the two-layer aerosol model on DSSR was more pronounced under dust conditions than clear-sky conditions.(4)Using the localized clear-sky DSSR inversion model and its required parameters,simulations were also conducted to capture the spatiotemporal distribution of DSSR under clear-sky conditions in Xinjiang from 2017 to 2019.The annual average DSSR_(SBD)under clear-sky conditions in Xinjiang during 2017–2019 was 606.78 W m^(-2),while DSSR from CERES(DSSR_(CER))under the same conditions was generally higher(703.95 W m^(-2)).(5)It is found that satellite remote sensing products experienced data loss in high-altitude snow areas,where numerical simulation technology could serve as a valuable complement.展开更多
The Altyn Tagh fault is the northern boundary of Tibetan Plateau. As one of the most well-known strike-slip fault in the world, great achievements on tectonic deformation and Late Qua- ternary slip rate have been made...The Altyn Tagh fault is the northern boundary of Tibetan Plateau. As one of the most well-known strike-slip fault in the world, great achievements on tectonic deformation and Late Qua- ternary slip rate have been made. However, there is a long-lasting debate on whether the Altyn Tagh fault extends into the Jinta Basin or even eastward. In this paper, we use satellite image interpretation, field investigation, trench excavation, and optical stimulated luminescence dating to study newly found NS striking scarps in the eastern end of Jinta Nan Shan. The results are as follows： firstly, a group of normal faults develop on terrace T2 of Heihe River, the total length amounts to -40 km, total scarp height is 304-5 m; secondly, four paleoseismic events have been interpreted from three trenches, approximate ages of events are 79.97±19.14 ka BP, 62.55±13.10~55.41±10.77 ka BP, before 16.89±2.08 ka BP, 8.52±1.49 ka BP, respectively; thirdly, just like NS normal faults in the western end of Altyn Tagh fault, the newly found NS extensional faults are likely the terminating tectonics of the eastern end of Altyn Tagh fault, the large Altyn Tagh fault may end in the eastern end of Jinta Nan Shan.展开更多
Cell source is the key to decellularized matrix(DM)strategy.This study compared 3 cell types,osteocytes with/without dominant active Wnt/β-catenin signaling(daCO and WTO)and bone marrow stromal cells(BMSCs)for their ...Cell source is the key to decellularized matrix(DM)strategy.This study compared 3 cell types,osteocytes with/without dominant active Wnt/β-catenin signaling(daCO and WTO)and bone marrow stromal cells(BMSCs)for their DMs in bone repair.Decellularization removes all organelles and>95%DNA,and retained>74%collagen and>71%GAG,maintains the integrity of cell basement membrane with dense boundaries showing oval and honeycomb structure in osteocytic DM and smooth but irregular shape in the BMSC-DM.DM produced higher cell survival rate(90%)and higher proliferative activity.In vitro,daCO-DM induces more and longer stress fibers in BMSCs,conducive to cell adhesion,spreading,and osteogenic differentiation.8-wk after implantation of the critical-sized parietal bone defect model,daCO-DM formed tight structures,composed of a large number of densely-arranged type-I collagen under polarized light microscope,which is similar to and integrated with host bone.BV/TV(>54%)was 1.5,2.9,and 3.5 times of WTO-DM,BMSC-DM,and none-DM groups,and N.Ob/T.Ar(3.2×10^(2)/mm^(2))was 1.7,2.9,and 3.3 times.At 4-wk,daCO-DM induced osteoclastogenesis,2.3 times higher than WTO-DM;but BMSC-DM or none-DM didn't.daCO-DM increased the expression of RANKL and MCSF,Vegfa and Angpt1,and Ngf in BMSCs,which contributes to osteoclastogenesis,angiogenesis,and neurogenesis,respectively.daCO-DM promoted H-type vessel formation and nerve markersβ3-tubulin and NeuN expression.Conclusion:daCO-DM produces metabolic and neurovascularized organoid bone to accelerate the repair of bone defects.These features are expected to achieve the effect of autologous bone transplantation,suitable for transformation application.展开更多
Gas molecules(such as CH4,CO,H2O,H2S,NH_3)adsorption on the pure and Au-doped WO3(001)surface have been studied by Density functional theory calculations with generalized gradient approximation.Based on the the calcul...Gas molecules(such as CH4,CO,H2O,H2S,NH_3)adsorption on the pure and Au-doped WO3(001)surface have been studied by Density functional theory calculations with generalized gradient approximation.Based on the the calculation of adsorption energy,we found the most stable adsorption site for gas molecules by comparing the adsorption energies of different gas molecules on the WO3(001)surface.We have also compared the adsorption energy of five different gas molecules on the WO3(001)surface,our calculation results show that when the five kinds of gases are adsorbed on the pure WO3(001)surface,the order of the surface adsorption energy is CO>H2S>CH4>H2O>NH3.And the results show that NH3 is the most easily adsorbed gas among the other four gases adsorbed on the surface of pure WO3(001)surface.We also calculated the five different gases on the Au-doped WO3(001)surface.The order of adsorption energy was found to be different from the previous calculation:CO>CH4>H2S>H2O>NH3.These results provide a new route for the potential applications of Au-doped WO3 in gas molecules adsorption.展开更多
The SnO_(2)-based family is a traditional but important gas-sensitive material.However,the requirement for high working temperature limits its practical application.Much work has been done to explore ways to improve i...The SnO_(2)-based family is a traditional but important gas-sensitive material.However,the requirement for high working temperature limits its practical application.Much work has been done to explore ways to improve its gas-sensing performance at room temperature(RT).For this report,SnO_(2),SnO,and SnO/SnO_(2) heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination.Pure SnO_(2) requires a high operating temperature(145℃),while SnO/SnO_(2) heterojunction exhibits an excellent performance for sensing NO_(2) at RT.Moreover,SnO/SnO_(2) exhibits a fast response,of 32 s,to 50 ppm NO_(2) at RT(27℃),which is much faster than that of SnO(139 s).The superior sensing properties of SnO/SnO_(2) heterojunction are attributed to the unique hierarchical structures,large number of adsorption sites,and enhanced electron transport.Our results show that SnO/SnO_(2) heterojunction can be used as a promising high-performance NO_(2) sensitive material at RT.展开更多
A novel low-temperature SnO_(2) gas sensor was prepared and studied on silicon nanostructures formed by femtosecond laser irradiation.By applying a bias voltage on the silicon substrate to alter the charge distributio...A novel low-temperature SnO_(2) gas sensor was prepared and studied on silicon nanostructures formed by femtosecond laser irradiation.By applying a bias voltage on the silicon substrate to alter the charge distribution on the surface of the SnO_(2),carbon monoxide(CO),and ammonia(NH_(3))gas can be distinguished by the same sensor at room temperature.The experimental results are explained with a mechanism that the sensor works at low temperature because of adsorption of gas molecules that trap electrons to the surface of the SnO_(2).展开更多
Heat pipes play a critical role in determining the operations,safety,and energy efficiency of electronics.The main focus to improve the heat pipe performance is on the evaporator design or wicking structures.However,t...Heat pipes play a critical role in determining the operations,safety,and energy efficiency of electronics.The main focus to improve the heat pipe performance is on the evaporator design or wicking structures.However,the intrinsic limitation comes from the condenser,which is fundamentally constrained by inefficient filmwise condensation(FWC).In this study,we successfully achieved a peak effective thermal conductivity(keff)of~140 kW/(m·K)on widely used groove heat pipes by implementing sustianble dropwise condensation(DWC)and integrating with enhanced evaporator.To better understand the working mechanisms of the ultraefficient heat pipe,both the evaporator and condenser of the heat pipes have been modified accordingly.Our results show that up to 296%enhancements on the keff can be achieved under various inclination angles by only inducing DWC in the condenser section.The drawback of temperature fluctuations induced by DWC in smooth heat pipes appears to be effectively solved using the grooves‐wicking structure.Furthermore,by integrating the nanostructured evaporator,the keff of the heat pipe can be boosted up to 517%compared to conventional groove heat pipes.This study,for the first time,demonstrates the huge potential of engineering both the condenser and evaporator simultaneously in developing ultraefficient heat pipes.展开更多
基金the National Natural Science Foundation of China(Nos.U1601220,82072450,and 81672118)Chongqing Science and Technology Commission-Basic Science and Frontier Technology Key Project(No.cstc2015jcyjBX0119)Chongqing Medical University Intelligent Medicine Research Project(No.ZHYX202115).
文摘Since 3D printed hard materials could match the shape of bone,cell survival and fate determination towards osteoblasts in such materials have become a popular research target.In this study,a scaffold of hardmaterial for 3D fabrication was designed to regulate developmental signal(Notch)transduction guiding osteoblast differentiation.We established a polycaprolactone(PCL)and cell-integrated 3D printing system(PCI3D)to reciprocally print the beams of PCL and cell-laden hydrogel for a module.This PCI3D module holds good cell viability of over 87%,whereas cells show about sixfold proliferation in a 7-day culture.The osteocytic MLO-Y4 was engineered to overexpress Notch ligand Dll4,making up 25%after mixing with 75%stromal cells in the PCI3D module.Osteocytic Dll4,unlike other delta-like family members such as Dll1 or Dll3,promotes osteoblast differentiation and themineralization of primary mouse and a cell line of bone marrow stromal cells when cultured in a PCI3D module for up to 28 days.Mechanistically,osteocytic Dll4 could not promote osteogenic differentiation of the primary bone marrow stromal cells(BMSCs)after conditional deletion of the Notch transcription factor RBPjκby Cre recombinase.These data indicate that osteocytic Dll4 activates RBPjκ-dependent canonical Notch signaling in BMSCs for their oriented differentiation towards osteoblasts.Additionally,osteocytic Dll4 holds a great potential for angiogenesis in human umbilical vein endothelial cells within modules.Our study reveals that osteocytic Dll4 could be the osteogenic niche determining cell fate towards osteoblasts.This will open a new avenue to overcome the current limitation of poor cell viability and low bioactivity of traditional orthopedic implants.
基金the National Natural Science Foundation of China(U21A20206,Chun-Peng Song)the Project of Sanya Yazhou Bay Science and Technology City(SCKJJYRC-2022-78,Baozhu Li)+1 种基金the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(21IRTSTHN019,Siyi Guo)the 111 Project of China(D16014).
文摘Gibberellin(GA)functions in plant growth and development.However,genes involved in the biosynthesis and regulation of GA in crop plants are poorly understood.We isolated the mutant gad5-1(GAAssociated Dwarf 5),characterized by dwarfing,short internodes,and dark green and short leaves.Map-based gene cloning and allelic verification confirmed that ZmGAD5 encodes ent-kaurenoic acid oxidase(KAO),which catalyzes KA(ent-kaurenoic acid)to GA12 conversion during GA biosynthesis in maize.ZmGAD5 is localized to the endoplasmic reticulum and is present in multiple maize organs.In gad5-1,the expression of ZmGAD5 is severely reduced,and the levels of the direct substrate of KAO,KA,is increased,leading to a reduction in GA content.The abnormal phenotype of gad5-1 was restored by exogenous application of GA3.The biomass,plant height,and levels of GA12 and GA3 in transgenic Arabidopsis overexpressing ZmGAD5 were increased in comparison with the corresponding controls Col-0.These findings deepen our understanding of genes involved in GA biosynthesis,and could lead to the development of maize lines with improved architecture and higher planting-density tolerance.
基金supported by the National Natural Science Foundation of China(U21A20206,32322010)the Program for Innovative Research Team(in Science and Technology)at the University of Henan Province(21IRTSTHN019)。
文摘Reactive oxygen species(ROS)are produced as undesirable by-products of metabolism in various cellular compartments,especially in response to unfavorable environmental conditions,throughout the life cycle of plants.Stressinduced ROS production disrupts normal cellular function and leads to oxidative damage.To cope with excessive ROS,plants are equipped with a sophisticated antioxidative defense system consisting of enzymatic and non-enzymatic components that scavenge ROS or inhibit their harmful effects on biomolecules.Nonetheless,when maintained at relatively low levels,ROS act as signaling molecules that regulate plant growth,development,and adaptation to adverse conditions.Here,we provide an overview of current approaches for detecting ROS.We also discuss recent advances in understanding ROS signaling,ROS metabolism,and the roles of ROS in plant growth and responses to various abiotic stresses.
基金Science and Technology Planning Program of Xinjiang(2022E01047)National Natural Science Foundation of China(42030612 and 41905131)+2 种基金Scientific Research Program Funded by Education Department of Shaanxi Provincial Government(23JK0625)Natural Science Basic Research Program of Shaanxi Province(2021JQ-768)Social Science Planning Fund Program of Xi’an City(23JX150)。
文摘To harness the rich solar energy resources in Xinjiang Region of Northwest China,this study tries to address the issue of lack of downward surface shortwave radiation(DSSR)observations and the need to improve the accuracy of satellite retrieval and numerical simulation of DSSR under varied sky and meteorological conditions.(1)A two-layer aerosol model specific to Xinjiang was developed to capture the vertical distributions of aerosols based on multiple data sources including lidar,GPS sounding,ground meteorological observations,and profiles from the ECMWF reanalysis version 5(ERA5)data.The results show that the ERA5/PBLH(planetary boundary layer height)and ERA5/ALH(aerosol layer height)could be used to establish the two-layer aerosol model and characterize the vertical distribution of aerosols in Xinjiang Region.(2)Using the Santa Barbara Discrete Atmospheric Radiative Transfer(SBDART)model,a localized inverse model of clear-sky DSSR was established.After parameter adjustment and using the optimal combination of input parameters for DSSR simulation together with the two-layer aerosol model,the model-simulated DSSR(DSSRSBD)under clear-sky conditions improved significantly compared to the initial results,with all fitting indices greatly improved.(3)In addition,the study demonstrated that the impact of the two-layer aerosol model on DSSR was more pronounced under dust conditions than clear-sky conditions.(4)Using the localized clear-sky DSSR inversion model and its required parameters,simulations were also conducted to capture the spatiotemporal distribution of DSSR under clear-sky conditions in Xinjiang from 2017 to 2019.The annual average DSSR_(SBD)under clear-sky conditions in Xinjiang during 2017–2019 was 606.78 W m^(-2),while DSSR from CERES(DSSR_(CER))under the same conditions was generally higher(703.95 W m^(-2)).(5)It is found that satellite remote sensing products experienced data loss in high-altitude snow areas,where numerical simulation technology could serve as a valuable complement.
基金jointly supported by the Basic Research Project, Institute of Earthquake Prediction, China Earthquake Administration (No. 2013IESLZ07)the National Natural Science Foundation of China (No. 41602225)the Special Fund for China Earthquake Research (No. 201408023)
文摘The Altyn Tagh fault is the northern boundary of Tibetan Plateau. As one of the most well-known strike-slip fault in the world, great achievements on tectonic deformation and Late Qua- ternary slip rate have been made. However, there is a long-lasting debate on whether the Altyn Tagh fault extends into the Jinta Basin or even eastward. In this paper, we use satellite image interpretation, field investigation, trench excavation, and optical stimulated luminescence dating to study newly found NS striking scarps in the eastern end of Jinta Nan Shan. The results are as follows： firstly, a group of normal faults develop on terrace T2 of Heihe River, the total length amounts to -40 km, total scarp height is 304-5 m; secondly, four paleoseismic events have been interpreted from three trenches, approximate ages of events are 79.97±19.14 ka BP, 62.55±13.10~55.41±10.77 ka BP, before 16.89±2.08 ka BP, 8.52±1.49 ka BP, respectively; thirdly, just like NS normal faults in the western end of Altyn Tagh fault, the newly found NS extensional faults are likely the terminating tectonics of the eastern end of Altyn Tagh fault, the large Altyn Tagh fault may end in the eastern end of Jinta Nan Shan.
基金National Natural Science Foundation of China U1601220(X.T.),81672118(X.T.),82072450(X.T.),82002310(Y.M.)Chongqing Science and Technology Commission—Basic Science and Frontier Technology Key Project cstc2015jcyjBX0119(X.T.)CQMU Program for Youth Innovation in Future Medicine,W0075(Y.M.).
文摘Cell source is the key to decellularized matrix(DM)strategy.This study compared 3 cell types,osteocytes with/without dominant active Wnt/β-catenin signaling(daCO and WTO)and bone marrow stromal cells(BMSCs)for their DMs in bone repair.Decellularization removes all organelles and>95%DNA,and retained>74%collagen and>71%GAG,maintains the integrity of cell basement membrane with dense boundaries showing oval and honeycomb structure in osteocytic DM and smooth but irregular shape in the BMSC-DM.DM produced higher cell survival rate(90%)and higher proliferative activity.In vitro,daCO-DM induces more and longer stress fibers in BMSCs,conducive to cell adhesion,spreading,and osteogenic differentiation.8-wk after implantation of the critical-sized parietal bone defect model,daCO-DM formed tight structures,composed of a large number of densely-arranged type-I collagen under polarized light microscope,which is similar to and integrated with host bone.BV/TV(>54%)was 1.5,2.9,and 3.5 times of WTO-DM,BMSC-DM,and none-DM groups,and N.Ob/T.Ar(3.2×10^(2)/mm^(2))was 1.7,2.9,and 3.3 times.At 4-wk,daCO-DM induced osteoclastogenesis,2.3 times higher than WTO-DM;but BMSC-DM or none-DM didn't.daCO-DM increased the expression of RANKL and MCSF,Vegfa and Angpt1,and Ngf in BMSCs,which contributes to osteoclastogenesis,angiogenesis,and neurogenesis,respectively.daCO-DM promoted H-type vessel formation and nerve markersβ3-tubulin and NeuN expression.Conclusion:daCO-DM produces metabolic and neurovascularized organoid bone to accelerate the repair of bone defects.These features are expected to achieve the effect of autologous bone transplantation,suitable for transformation application.
基金the Key Projects of National Natural Science Foundation of China(U1704255)the National Natural Science Foundation of China(11804081)+6 种基金the National Natural Science Foundation of China(Grant No.21603109)the Henan Joint Fund of the National Natural Science Foundation of China(Grant No.U1404216)the Natural Science Foundation of Henan Province(182102210305)the Natural Science Foundation of Henan Province(19B430003,20A430016,182300410288)the Key Research Project for the Universities of Henan Province(19A140009)the Doctoral Foundation of Henan Polytechnic University(B2018-38)the Open Project of Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province(LRME201601)。
文摘Gas molecules(such as CH4,CO,H2O,H2S,NH_3)adsorption on the pure and Au-doped WO3(001)surface have been studied by Density functional theory calculations with generalized gradient approximation.Based on the the calculation of adsorption energy,we found the most stable adsorption site for gas molecules by comparing the adsorption energies of different gas molecules on the WO3(001)surface.We have also compared the adsorption energy of five different gas molecules on the WO3(001)surface,our calculation results show that when the five kinds of gases are adsorbed on the pure WO3(001)surface,the order of the surface adsorption energy is CO>H2S>CH4>H2O>NH3.And the results show that NH3 is the most easily adsorbed gas among the other four gases adsorbed on the surface of pure WO3(001)surface.We also calculated the five different gases on the Au-doped WO3(001)surface.The order of adsorption energy was found to be different from the previous calculation:CO>CH4>H2S>H2O>NH3.These results provide a new route for the potential applications of Au-doped WO3 in gas molecules adsorption.
基金the support from the National Natural Science Foundation of China(Grant No.52073165)the Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(Grant No.KLIFMD202202)the Natural Science Foundation of Shaanxi Provincial Department of Education(Grant No.20JT008).
文摘The SnO_(2)-based family is a traditional but important gas-sensitive material.However,the requirement for high working temperature limits its practical application.Much work has been done to explore ways to improve its gas-sensing performance at room temperature(RT).For this report,SnO_(2),SnO,and SnO/SnO_(2) heterojunction was successfully synthesized by a facile hydrothermal combined with subsequent calcination.Pure SnO_(2) requires a high operating temperature(145℃),while SnO/SnO_(2) heterojunction exhibits an excellent performance for sensing NO_(2) at RT.Moreover,SnO/SnO_(2) exhibits a fast response,of 32 s,to 50 ppm NO_(2) at RT(27℃),which is much faster than that of SnO(139 s).The superior sensing properties of SnO/SnO_(2) heterojunction are attributed to the unique hierarchical structures,large number of adsorption sites,and enhanced electron transport.Our results show that SnO/SnO_(2) heterojunction can be used as a promising high-performance NO_(2) sensitive material at RT.
基金supported by the National Science Foundation under Grant No.[CMMI-1031111].
文摘A novel low-temperature SnO_(2) gas sensor was prepared and studied on silicon nanostructures formed by femtosecond laser irradiation.By applying a bias voltage on the silicon substrate to alter the charge distribution on the surface of the SnO_(2),carbon monoxide(CO),and ammonia(NH_(3))gas can be distinguished by the same sensor at room temperature.The experimental results are explained with a mechanism that the sensor works at low temperature because of adsorption of gas molecules that trap electrons to the surface of the SnO_(2).
基金The National Aeronautics and Space Administration,Grant/Award Number:20‐EPSCoR2020‐0064。
文摘Heat pipes play a critical role in determining the operations,safety,and energy efficiency of electronics.The main focus to improve the heat pipe performance is on the evaporator design or wicking structures.However,the intrinsic limitation comes from the condenser,which is fundamentally constrained by inefficient filmwise condensation(FWC).In this study,we successfully achieved a peak effective thermal conductivity(keff)of~140 kW/(m·K)on widely used groove heat pipes by implementing sustianble dropwise condensation(DWC)and integrating with enhanced evaporator.To better understand the working mechanisms of the ultraefficient heat pipe,both the evaporator and condenser of the heat pipes have been modified accordingly.Our results show that up to 296%enhancements on the keff can be achieved under various inclination angles by only inducing DWC in the condenser section.The drawback of temperature fluctuations induced by DWC in smooth heat pipes appears to be effectively solved using the grooves‐wicking structure.Furthermore,by integrating the nanostructured evaporator,the keff of the heat pipe can be boosted up to 517%compared to conventional groove heat pipes.This study,for the first time,demonstrates the huge potential of engineering both the condenser and evaporator simultaneously in developing ultraefficient heat pipes.
