The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of produ...The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of production-living-ecological spaces for sustainable and high-quality development in the TGRA.This study investigated the dynamic variation of production-living-ecological spaces in the TGRA by employing land use data in 2000,2005,2010,2015,and 2018,and detected the influencing factors by using the Geographic detector(GeoDetector).Results implied that the structure and dynamic trajectories of production-living-ecological spaces in the TGRA varied in both horizontal and vertical directions,and the study area was dominated by ecological space.A spatial orientation towards the northeast was detected in the evolution of production-living-ecological spaces during 2000-2018.In terms of quantity,the transition from ecological space(grassland and woodland)to agriculture land accounted for the largest proportion from 2000 to 2018.However,the reverse transition from agriculture land to ecological space has increased since 2000 with the efforts of“Grain for Green”.In terms of temporal scale,there was a fluctuating trend in production space with the continuous expansion of living space,while ecological space showed an inverted U-shaped trend during 2000-2018.The dynamic pattern of production-living-ecological spaces in the TGRA was influenced by both physical and socio-economic variables as basic determinants and dominant driving factors,respectively.Finally,the harmonization and protection of production-living-ecological spaces still require policy-makers’efforts.This work may have potential in advancing our understanding about land use conflicts,and provide a reference for rational layout of spatial functions and the realization of sustainable development in the TGRA.展开更多
Control over magnetic properties by optical stimulation is not only interesting from the physics point of view,but also important for practical applications such as magneto-optical devices.Here,based on a simple tight...Control over magnetic properties by optical stimulation is not only interesting from the physics point of view,but also important for practical applications such as magneto-optical devices.Here,based on a simple tight-binding(TB)model,we propose a general theory of light-induced magnetic phase transition(MPT)in antiferromagnets.Considering the fact that the bandgap of the antiferromagnetic(AFM)phase is usually larger than that of the ferromagnetic(FM)one for a given system,we suggest that light-induced electronic excitation prefers to stabilize the FM state over the AFM one,and will induce an MPT from AFM phase to FM phase once a critical photocarrier concentration(αc)is reached.This theory has been confirmed by performing firstprinciples calculations on a series of 2D van der Waals(vd W)antiferromagnets.Interestingly,a linear relationship betweenαc and the intrinsic material parameters is obtained,in agreement with our TB model analysis.Our general theory paves a new way to manipulate 2D magnetism with high speed and superior resolution.展开更多
Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propo...Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.展开更多
A main challenge for the development of two-dimensional devices based on atomically thin transition-metal dichalcogenides(TMDs)is the realization of metal–semiconductor junctions(MSJs)with low contact resistance and ...A main challenge for the development of two-dimensional devices based on atomically thin transition-metal dichalcogenides(TMDs)is the realization of metal–semiconductor junctions(MSJs)with low contact resistance and high charge transport capability.However,traditional metal–TMD junctions usually suffer from strong Fermi-level pinning(FLP)and chemical disorder at the interfaces,resulting in weak device performance and high energy consump-tion.By means of high-throughput first-principles calculations,we report an attractive solution via the formation of van der Waals(vdW)contacts between metallic and semiconducting TMDs.We apply a phase-engineering strategy to create a monolayer TMD database for achieving a wide range of work func-tions and band gaps,hence offering a large degree of freedom to construct TMD vdW MSJs with desired contact types.The Schottky barrier heights and contact types of 728 MSJs have been identified and they exhibit weak FLP(-0.62 to-0.90)as compared with the traditional metal–TMD junctions.We find that the interfacial interactions of the MSJs bring a delicate competition between the FLP strength and carrier tunneling efficiency,which can be uti-lized to screen high-performance MSJs.Based on a set of screening criteria,four potential TMD vdW MSJs(e.g.,NiTe_(2)/ZrSe_(2),NiTe_(2)/PdSe_(2),HfTe_(2)/PdTe_(2),TaSe_(2)/MoTe_(2))with Ohmic contact,weak FLP,and high carrier tunneling probability have been predicted.This work not only provides a fundamental understanding of contact properties of TMD vdW MSJs but also renders their huge potential for electronics and optoelectronics.展开更多
基金the National Natural Science Foundation of China(41971215,42371205)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2022317).
文摘The Three Gorges Reservoir Area(TGRA)is an important ecological barrier in the Yangtze River Basin,China.Therefore,it is of great importance to understand the spatio-temporal variation and the driving factors of production-living-ecological spaces for sustainable and high-quality development in the TGRA.This study investigated the dynamic variation of production-living-ecological spaces in the TGRA by employing land use data in 2000,2005,2010,2015,and 2018,and detected the influencing factors by using the Geographic detector(GeoDetector).Results implied that the structure and dynamic trajectories of production-living-ecological spaces in the TGRA varied in both horizontal and vertical directions,and the study area was dominated by ecological space.A spatial orientation towards the northeast was detected in the evolution of production-living-ecological spaces during 2000-2018.In terms of quantity,the transition from ecological space(grassland and woodland)to agriculture land accounted for the largest proportion from 2000 to 2018.However,the reverse transition from agriculture land to ecological space has increased since 2000 with the efforts of“Grain for Green”.In terms of temporal scale,there was a fluctuating trend in production space with the continuous expansion of living space,while ecological space showed an inverted U-shaped trend during 2000-2018.The dynamic pattern of production-living-ecological spaces in the TGRA was influenced by both physical and socio-economic variables as basic determinants and dominant driving factors,respectively.Finally,the harmonization and protection of production-living-ecological spaces still require policy-makers’efforts.This work may have potential in advancing our understanding about land use conflicts,and provide a reference for rational layout of spatial functions and the realization of sustainable development in the TGRA.
基金supported by the National Natural Science Foundation of China(Grant Nos.11991061,11825403,and 12188101)the Guangdong Major Project of Basic and Applied Basic Research(Future functional materials under extreme conditions-2021B0301030005)the support from the National Natural Science Foundation of China(NSAF,Grant No.U1930402)。
文摘Control over magnetic properties by optical stimulation is not only interesting from the physics point of view,but also important for practical applications such as magneto-optical devices.Here,based on a simple tight-binding(TB)model,we propose a general theory of light-induced magnetic phase transition(MPT)in antiferromagnets.Considering the fact that the bandgap of the antiferromagnetic(AFM)phase is usually larger than that of the ferromagnetic(FM)one for a given system,we suggest that light-induced electronic excitation prefers to stabilize the FM state over the AFM one,and will induce an MPT from AFM phase to FM phase once a critical photocarrier concentration(αc)is reached.This theory has been confirmed by performing firstprinciples calculations on a series of 2D van der Waals(vd W)antiferromagnets.Interestingly,a linear relationship betweenαc and the intrinsic material parameters is obtained,in agreement with our TB model analysis.Our general theory paves a new way to manipulate 2D magnetism with high speed and superior resolution.
基金Project supported by the National Natural Science Foundation of China(Grant No.NSFC 12175107)the Natural Science Foundation of Nanjing Vocational University of Industry Technology,China(Grant No.YK22-02-08)+3 种基金the Qing Lan Project of Jiangsu Province,Chinathe Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX23_0964)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20230347)the Fund from the Research Center of Industrial Perception and Intelligent Manufacturing Equipment Engineering of Jiangsu Province,China(Grant No.ZK21-05-09)。
文摘Photonic spin Hall effect(PSHE), as a novel physical effect in light–matter interaction, provides an effective metrological method for characterizing the tiny variation in refractive index(RI). In this work, we propose a multi-functional PSHE sensor based on VO_(2), a material that can reveal the phase transition behavior. By applying thermal control, the mutual transformation into different phase states of VO_(2) can be realized, which contributes to the flexible switching between multiple RI sensing tasks. When VO_(2) is insulating, the ultrasensitive detection of glucose concentrations in human blood is achieved. When VO_(2) is in a mixed phase, the structure can be designed to distinguish between the normal cells and cancer cells through no-label and real-time monitoring. When VO_(2) is metallic, the proposed PSHE sensor can act as an RI indicator for gas analytes. Compared with other multi-functional sensing devices with the complex structures, our design consists of only one analyte and two VO_(2) layers, which is very simple and elegant. Therefore, the proposed VO_(2)-based PSHE sensor has outstanding advantages such as small size, high sensitivity, no-label, and real-time detection, providing a new approach for investigating tunable multi-functional sensors.
基金National Natural Science Foundation of China,Grant/Award Number:62174151Natural Science Foundation of Zhejiang Province,Grant/Award Numbers:LZ22F040003,Q21A050007。
文摘A main challenge for the development of two-dimensional devices based on atomically thin transition-metal dichalcogenides(TMDs)is the realization of metal–semiconductor junctions(MSJs)with low contact resistance and high charge transport capability.However,traditional metal–TMD junctions usually suffer from strong Fermi-level pinning(FLP)and chemical disorder at the interfaces,resulting in weak device performance and high energy consump-tion.By means of high-throughput first-principles calculations,we report an attractive solution via the formation of van der Waals(vdW)contacts between metallic and semiconducting TMDs.We apply a phase-engineering strategy to create a monolayer TMD database for achieving a wide range of work func-tions and band gaps,hence offering a large degree of freedom to construct TMD vdW MSJs with desired contact types.The Schottky barrier heights and contact types of 728 MSJs have been identified and they exhibit weak FLP(-0.62 to-0.90)as compared with the traditional metal–TMD junctions.We find that the interfacial interactions of the MSJs bring a delicate competition between the FLP strength and carrier tunneling efficiency,which can be uti-lized to screen high-performance MSJs.Based on a set of screening criteria,four potential TMD vdW MSJs(e.g.,NiTe_(2)/ZrSe_(2),NiTe_(2)/PdSe_(2),HfTe_(2)/PdTe_(2),TaSe_(2)/MoTe_(2))with Ohmic contact,weak FLP,and high carrier tunneling probability have been predicted.This work not only provides a fundamental understanding of contact properties of TMD vdW MSJs but also renders their huge potential for electronics and optoelectronics.
