The luminescence of most phosphors activated with rare earth ions decreases when the doping amounts of activators exceed their critical concentrations,while some phosphors with special anisotropic structures have been...The luminescence of most phosphors activated with rare earth ions decreases when the doping amounts of activators exceed their critical concentrations,while some phosphors with special anisotropic structures have been found to have no concentration quenching effect.In this work,an unusual concentration quenching phenomenon being different from the two mentioned above was observed in GdGaTi_(2)O_(7):xEu^(3+),that is,the luminescence intensity of the phosphors remains almost constant in the concentration range of x from 0.3 to 0.6,and it is obviously quenched when x is greater than 0.6.The reason for this phenomenon is deduced to be closely connected with the preferential distribution of quenching centres along the one-dimensional chains of rare earth ions in the host.The results of the first-principle calculations show that the confined chains for energy migration favour the formation of defects,and the formation energy of Gd vacancies in the chains increases with the concentration of Eu^(3+).This special chain structure accelerates the quenching of luminescence for phosphors with higher contents of Eu^(3+),thereby resulting in the unusual concentration-dependent luminescence in GdGaTi_(2)O_(7):Eu^(3+).Moreover,the relatively balanced and excellent comprehensive performances of GdGaTi_(2)O_(7):Eu^(3+),including high doping concentration,quantum efficiency of 71%,colour purity of 93.5%,colour rendering index of 91,and high thermal stability(the luminescence intensity at 400 K is 71%of that at room temperature),indicate a promising application prospect as a red component in WLEDs.展开更多
Aqueous Mg–air batteries are promising candidates for large-scale energy storage,but their practical application is significantly hindered by water-induced parasitic reactions and the chunk effect.In this study,tauri...Aqueous Mg–air batteries are promising candidates for large-scale energy storage,but their practical application is significantly hindered by water-induced parasitic reactions and the chunk effect.In this study,taurine(Tau)is an effective electrolyte additive for aqueous Mg–air batteries utilizing various magnesium anodes.The non-sacrificial Tau molecules,possessing both donor and acceptor groups,disrupt the inherent hydrogen bond network of H_(2)O and replace solvated H_(2)O in the Mg^(2+)solvation sheath,forming dynamic adsorption on Mg and creating a hydrophobic electric double layer.Consequently,taurine inhibits H_(2)O attack on Mg,promoting uniform Mg stripping.An appropriate amount of Tau not only enhances the discharge activity of the AZ31 anode but also suppresses its self-discharge phenomenon,achieving a surprising effect of simultaneously boosting voltage and anode utilization.Therefore,0.2 M Tau was identified as the optimal electrolyte concentration and successfully incorporated in Mg–air batteries utilizing various routine Mg anodes(such as VW83,VW103,and LA103Z).The results demonstrate that Tau effectively enhances the discharge properties for Mg–air batteries employing various magnesium anodes.展开更多
Since the 1990s,femtosecond laser two-photon absorption(TPA),which enables point-by-point photopolymerization,has been a tool for making threedimensional(3D)microstructures.Approximately 10 years later,Kawata et al.im...Since the 1990s,femtosecond laser two-photon absorption(TPA),which enables point-by-point photopolymerization,has been a tool for making threedimensional(3D)microstructures.Approximately 10 years later,Kawata et al.improved the spatial resolution of TPA fabrication to120 nm,far beyond the diffraction limit of the 780 nm laser source.1 The essential mechanism of this nanoscale fabrication lies in the nonlinear effect,in which TPA-induced photopolymerization occurs only in the vicinity of the focal spot.展开更多
Non-Hermitian(NH)systems have revealed unique topological phenomena that are not observed in Hermitian counterparts,such as novel topology classifications and the NH skin effect.In periodic NH systems,eigenenergies be...Non-Hermitian(NH)systems have revealed unique topological phenomena that are not observed in Hermitian counterparts,such as novel topology classifications and the NH skin effect.In periodic NH systems,eigenenergies become complex and exhibit windings in the complex plane,while eigenstate winding numbers,which are strictly integers in Hermitian systems,can take half-integer values.However,direct experimental observation of NH winding of both eigenenergies and eigenstates,especially the half-integer winding,remains a significant challenge.In this work,we utilize the orbital angular momentum(OAM)synthetic dimension to construct an NH topological lattice and achieve direct observation of both eigenstate and eigenenergy windings.We report the first experimental observation of a half-integer eigenstate winding number,and reveal the intrinsic relationship between the direction in the NH skin dynamics and eigenenergy windings.Furthermore,by partitioning the OAM chain into two semi-infinite chains,we observe zero boundary modes and demonstrate that their distributions are jointly determined by the winding numbers of both the eigenstates and eigenenergies.This work provides comprehensive insights into NH topologies and offers a new experimental platform for exploring NH phenomena.展开更多
基金financially supported by grants from the National Natural Science Foundation of China(NSFC no.51972347)the GDAS Project of Science and Technology Development(nos 2022GDASZH-2022010104,2022GDASZH-2022030604-04).
文摘The luminescence of most phosphors activated with rare earth ions decreases when the doping amounts of activators exceed their critical concentrations,while some phosphors with special anisotropic structures have been found to have no concentration quenching effect.In this work,an unusual concentration quenching phenomenon being different from the two mentioned above was observed in GdGaTi_(2)O_(7):xEu^(3+),that is,the luminescence intensity of the phosphors remains almost constant in the concentration range of x from 0.3 to 0.6,and it is obviously quenched when x is greater than 0.6.The reason for this phenomenon is deduced to be closely connected with the preferential distribution of quenching centres along the one-dimensional chains of rare earth ions in the host.The results of the first-principle calculations show that the confined chains for energy migration favour the formation of defects,and the formation energy of Gd vacancies in the chains increases with the concentration of Eu^(3+).This special chain structure accelerates the quenching of luminescence for phosphors with higher contents of Eu^(3+),thereby resulting in the unusual concentration-dependent luminescence in GdGaTi_(2)O_(7):Eu^(3+).Moreover,the relatively balanced and excellent comprehensive performances of GdGaTi_(2)O_(7):Eu^(3+),including high doping concentration,quantum efficiency of 71%,colour purity of 93.5%,colour rendering index of 91,and high thermal stability(the luminescence intensity at 400 K is 71%of that at room temperature),indicate a promising application prospect as a red component in WLEDs.
基金supported by the National Key Research and Development Program of China(grant no.2023YFB3710900 and 2021YFB3701004)the National Natural Science Foundation of China(grant no.51971054,52171055)+1 种基金the China Postdoctoral Science Foundation(2023M743274)the Liaoning Province Science and Technology Plan Project(2023JH2/101700356).
文摘Aqueous Mg–air batteries are promising candidates for large-scale energy storage,but their practical application is significantly hindered by water-induced parasitic reactions and the chunk effect.In this study,taurine(Tau)is an effective electrolyte additive for aqueous Mg–air batteries utilizing various magnesium anodes.The non-sacrificial Tau molecules,possessing both donor and acceptor groups,disrupt the inherent hydrogen bond network of H_(2)O and replace solvated H_(2)O in the Mg^(2+)solvation sheath,forming dynamic adsorption on Mg and creating a hydrophobic electric double layer.Consequently,taurine inhibits H_(2)O attack on Mg,promoting uniform Mg stripping.An appropriate amount of Tau not only enhances the discharge activity of the AZ31 anode but also suppresses its self-discharge phenomenon,achieving a surprising effect of simultaneously boosting voltage and anode utilization.Therefore,0.2 M Tau was identified as the optimal electrolyte concentration and successfully incorporated in Mg–air batteries utilizing various routine Mg anodes(such as VW83,VW103,and LA103Z).The results demonstrate that Tau effectively enhances the discharge properties for Mg–air batteries employing various magnesium anodes.
基金supported by the National Key R&D Program of China(no.2022YFB4600400)the National Natural Science Foundation of China(nos.T2325014,62205174,and 623B2042).
文摘Since the 1990s,femtosecond laser two-photon absorption(TPA),which enables point-by-point photopolymerization,has been a tool for making threedimensional(3D)microstructures.Approximately 10 years later,Kawata et al.improved the spatial resolution of TPA fabrication to120 nm,far beyond the diffraction limit of the 780 nm laser source.1 The essential mechanism of this nanoscale fabrication lies in the nonlinear effect,in which TPA-induced photopolymerization occurs only in the vicinity of the focal spot.
基金supported by the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0301400 and 2021ZD0301200)the National Natural Science Foundation of China(Grants No.11874343,92365205,11974334,12404576,and W2411001)+3 种基金the Postdoctoral Innovative Talents Support program(BX20230349)China Postdoctoral Science Foundation Funded Project(2024M763125)Xiaomi Young Talents Program,the Fundamental Research Funds for the Central Universities(Grant No.WK2030000085)the USTC Major Frontier Research Program(Grant No.LS2030000002).
文摘Non-Hermitian(NH)systems have revealed unique topological phenomena that are not observed in Hermitian counterparts,such as novel topology classifications and the NH skin effect.In periodic NH systems,eigenenergies become complex and exhibit windings in the complex plane,while eigenstate winding numbers,which are strictly integers in Hermitian systems,can take half-integer values.However,direct experimental observation of NH winding of both eigenenergies and eigenstates,especially the half-integer winding,remains a significant challenge.In this work,we utilize the orbital angular momentum(OAM)synthetic dimension to construct an NH topological lattice and achieve direct observation of both eigenstate and eigenenergy windings.We report the first experimental observation of a half-integer eigenstate winding number,and reveal the intrinsic relationship between the direction in the NH skin dynamics and eigenenergy windings.Furthermore,by partitioning the OAM chain into two semi-infinite chains,we observe zero boundary modes and demonstrate that their distributions are jointly determined by the winding numbers of both the eigenstates and eigenenergies.This work provides comprehensive insights into NH topologies and offers a new experimental platform for exploring NH phenomena.
