An effective approach for optimizing the rotor contour for variable reluctance(VR)resolver is presented.Using this approach,the procedure for optimizing the rotor is divided into two parts:the establishment of initial...An effective approach for optimizing the rotor contour for variable reluctance(VR)resolver is presented.Using this approach,the procedure for optimizing the rotor is divided into two parts:the establishment of initial shape curve,and then computation for the optimization.In order to simplify the process of the former,a shape function is constructed.And the latter is carried out by Taguchi optimization method and finite element method(FEM).An example of a 3-10 VR resolver is used to present the procedure of the optimization,and the testing results confirmed the effectivity of the approach.展开更多
The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of ...The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of a resolver is approached. And a polyphase multipole resolver is developed in the brushless DC torque motor. Finally, the experimental results are presented to illustrate the improvement of ripple torque in the brushless DC torque motor with the polyphase multipole resolver.展开更多
随着校园周边交通量的增加,交叉口的交通拥堵问题愈发严重,对行人和车辆的通行造成了较大困扰。为有效提高交叉口的通行效率,减少交通延误与排队长度,本文基于多元数据,利用Synchro交通仿真系统对校园周边的海棠路与丁香路交叉口进行了...随着校园周边交通量的增加,交叉口的交通拥堵问题愈发严重,对行人和车辆的通行造成了较大困扰。为有效提高交叉口的通行效率,减少交通延误与排队长度,本文基于多元数据,利用Synchro交通仿真系统对校园周边的海棠路与丁香路交叉口进行了信号优化研究。通过对现状交通流量数据的收集与分析,建立交叉口的仿真模型,评估现有信号配时方案的不足之处。基于流量/容量比率(V/C ratio)、控制延误(Control Delay)和服务水平(LOS)等关键指标,对信号配时方案进行了调整与优化。优化后的信号配时方案显著降低了高峰期的排队长度,改善了各交通流向的通行效率,并提高了整体的服务水平。结果表明:燃料消耗由155升降低至105升,减少了约32%,优化效果明显;停车次数从1359次/小时减少至1121次/小时,降低了约17.5%;总延误时间从549.2秒缩短至520.1秒,减少了约5.3%;交叉口的总体服务水平由E提升为D。研究表明,基于多元数据的Synchro信号优化对缓解校园周边交叉口的交通拥堵、提高通行效率和道路安全具有重要作用。With the increasing traffic volume around campuses, congestion at intersections has become more severe, causing significant challenges for pedestrians and vehicles. To effectively improve the efficiency of intersection traffic flow and reduce delays and queue lengths, this study conducts a signal optimization analysis for the intersection of Haitang Road and Dingxiang Road near a campus, using the Synchro traffic simulation system and multi-source data. By collecting and analyzing the existing traffic flow data, a simulation model of the intersection was established to evaluate the shortcomings of the current signal timing plan. Based on key indicators such as volume-to-capacity ratio (V/C ratio), control delay, and level of service (LOS), adjustments and optimizations were made to the signal timing. The optimized signal timing plan significantly reduced queue lengths during peak hours, improved traffic flow efficiency across all directions, and enhanced the overall level of service. Results showed that fuel consumption was reduced from 155 liters to 105 liters, a decrease of approximately 32%;the number of stops decreased from 1359 stops/hour to 1121 stops/hour, reducing by about 17.5%;and total delay time was reduced from 549.2 seconds to 520.1 seconds, a decrease of approximately 5.3%. The overall level of service of the intersection was improved from E to D. The study indicates that Synchro signal optimization based on multi-source data plays a crucial role in alleviating congestion, enhancing traffic efficiency, and improving road safety at campus-area intersections.展开更多
From October 30 to November 1,2025,Chinese President Xi Jinping traveled to the Republic of Korea(ROK)to attend the 32nd Asia-Pacific Economic Cooperation(APEC)Economic Leaders’Meeting and also pay a state visit to t...From October 30 to November 1,2025,Chinese President Xi Jinping traveled to the Republic of Korea(ROK)to attend the 32nd Asia-Pacific Economic Cooperation(APEC)Economic Leaders’Meeting and also pay a state visit to the country.This was Xi Jinping’s first overseas trip following the conclusion of the fourth plenary session of the 20th Communist Party of China Central Committee,underscoring its importance on China’s diplomatic agenda.展开更多
In this paper,we study the nonlinear stability problem for the two-dimensional Boussinesq system around the Couette flow in a finite channel with Navier-slip boundary condition for the velocity and Dirichlet boundary ...In this paper,we study the nonlinear stability problem for the two-dimensional Boussinesq system around the Couette flow in a finite channel with Navier-slip boundary condition for the velocity and Dirichlet boundary condition for the temperature with small viscosityνand small thermal diffusionμ.We establish that if the initial perturbation velocity and initial perturbation temperature satisfy ||u_(0)||H^(2)≤ε_(0) min{μ,ν}1/2, and ||θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||_(H^(1))≤εi min{μ,ν}^(5/6),for some smallε0 andε1 independent ofμ,ν,then the solution of the two-dimensional NavierStokes Boussinesq system does not transition away from the Couette flow for any time.展开更多
Nonlinear energy transfer is represented through eddy viscosity and stochastic forcing within the framework of resolvent analysis.Previous investigations estimate the contribution of eddy-viscosity-enhanced resolvent ...Nonlinear energy transfer is represented through eddy viscosity and stochastic forcing within the framework of resolvent analysis.Previous investigations estimate the contribution of eddy-viscosity-enhanced resolvent opera-tor to nonlinear energy transfer.The present article estimates the contribution of stochastic forcing to nonlinear energy transfer and demonstrates that the contribution of stochastic forcing cannot be ignored.These results are achieved by numerically comparing the eddy-viscosity-enhanced resolvent operator and stochastic forcing with nonlinear energy transfer in turbulent channel flows.Furthermore,the numerical results indicate that composite resolvent operators can improve the prediction of nonlinear energy transfer.展开更多
Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring th...Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring these radicals in reactions and investigating their structure-reactivity effect.In this work,vibrationally resolved laser-induced fluorescence(LIF)spectrum of the 3-cyclohexyl-1-propoxy radical was obtained in supersonic jet condition.Low energy conformers G′_(1)T_(2)G_(3)and T_(1)T_(2)G_(3)were identified as the spectral carriers.A red shift of the spectrum compared to that of the straight chain alkoxy radical with same number of carbon atoms suggested that the cyclohexyl ring was a slightly better electron donor than the linear alkyl group.Studies also showed that theαandβC cyclohexyl substitutions significantly weakened theβC-C bonds of the radicals,and conversely,the strength of the C-C bonds on cyclohexyl ring decreased as its distance from the O radical decreased.When cyclohexyl substitution occurred atγC,the stability of the 3-cyclohexyl-1-propoxy radical became comparable to that of straight chain alkoxy radicals.展开更多
Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for...Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for spatial domain identification tasks.Currently,most methods define adjacency relation between cells or spots by their spatial distance in SRT data,which overlooks key biological interactions like gene expression similarities,and leads to inaccuracies in spatial domain identification.To tackle this challenge,we propose a novel method,SpaGRA(https://github.com/sunxue-yy/SpaGRA),for automatic multi-relationship construction based on graph augmentation.SpaGRA uses spatial distance as prior knowledge and dynamically adjusts edge weights with multi-head graph attention networks(GATs).This helps SpaGRA to uncover diverse node relationships and enhance message passing in geometric contrastive learning.Additionally,SpaGRA uses these multi-view relationships to construct negative samples,addressing sampling bias posed by random selection.Experimental results show that SpaGRA presents superior domain identification performance on multiple datasets generated from different protocols.Using SpaGRA,we analyze the functional regions in the mouse hypothalamus,identify key genes related to heart development in mouse embryos,and observe cancer-associated fibroblasts enveloping cancer cells in the latest Visium HD data.Overall,SpaGRA can effectively characterize spatial structures across diverse SRT datasets.展开更多
Granulomatosis with polyangiitis(GPA)poses significant therapeutic challenges due to its susceptibility to concurrent infections and frequent relapses.Professor SHI Zaixiang proposed the therapeutic theory of lifting ...Granulomatosis with polyangiitis(GPA)poses significant therapeutic challenges due to its susceptibility to concurrent infections and frequent relapses.Professor SHI Zaixiang proposed the therapeutic theory of lifting depression and removing blood stasis,resolving phlegm and dispelling nodulation for GPA management.He identified the core pathogenesis as“Qi collapse with collateral obstruction and phlegm-stasis intermingling”,establishing the treatment principle of comprehensive intervention through ascending ancestral Qi,activating blood circulation,and resolving phlegm-stasis nodules.In clinical practice,Professor SHI emphasizes maintaining immune homeostasis with herbal medicine to enhance efficiency,while dynamically balancing Qi,blood,Yin,and Yang.Notably,he highlights the critical role of emotional factors in autoimmune disease progression.A representative case was provided to elucidate his clinical reasoning in GPA treatment.展开更多
Silicene,a silicon analog of graphene,holds promise for next-generation electronics due to its tunable bandgap and larger spin-orbit coupling.Despite extensive efforts to synthesize and characterize silicene on metal ...Silicene,a silicon analog of graphene,holds promise for next-generation electronics due to its tunable bandgap and larger spin-orbit coupling.Despite extensive efforts to synthesize and characterize silicene on metal substrates,bondresolved imaging of its atomic structure has remained elusive.Here,we report the fabrication and bond-resolved characterization of silicene on Au(111)substrate.Three silicene phases tuned by surface reconstruction and annealing temperatures are achieved.Using CO-terminated scanning tunneling microscopy(STM)tips,we resolve these silicene phases with atomic precision,determining their bond lengths,local strain,and geometric configurations.Furthermore,we correlate these structural features with their electronic properties,revealing the effect of strain and substrate interactions on the electronic properties of silicene.This work establishes silicene's intrinsic bonding topology and resolves longstanding controversies in silicene research.展开更多
Photocatalysts show broad application potential in clean energy conversion by utilizing solar energy for chemical transformations[1–3].However,single-component photocatalysts are severely limited in practical applica...Photocatalysts show broad application potential in clean energy conversion by utilizing solar energy for chemical transformations[1–3].However,single-component photocatalysts are severely limited in practical applications due to narrow light absorption ranges and high recombination rates of photogenerated carriers[4].S-scheme heterojunctions preserve optimal redox potentials,offering broad application prospects in solar energy conversion and environmental remediation[5,6].Since photocatalytic reactions occur predominantly at the material interface,a spatially resolved investigation of charge transfer is essential for understanding carrier dynamics at the nanoscale[7].In this context,the highlighted study employs Kelvin probe force microscopy(KPFM)to elucidate the real-space charge-transfer mechanisms in CdS/BiOBr S-scheme heterojunctions,providing direct and quantitative insight into interfacial charge behavior[8].展开更多
The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced application...The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced applications in nanoelectronics.However,an explicit analysis of its lattice dynamics and vibrational symmetries,pivotal for understanding the material’s peculiar ferroelectric and ferroionic behaviors,remains incomplete.Here,we employ angle-resolved polarized Raman spectroscopy in concert with first-principles calculations to systematically unravel the anisotropic lattice vibrations of CIPS single crystals.By analyzing the polarization-dependent Raman intensities,we determine the symmetry assignments and Raman tensors of all major vibrational modes,revealing good agreement with theoretical predictions.Furthermore,we demonstrate the utility of Raman spectroscopy as a sensitive and non-invasive probe for structural and ferroelectric order evolution by examining temperature-driven phase transitions and thickness-dependent polarization suppression in CIPS.Our findings establish a foundational framework for correlating lattice dynamics with functional properties in CIPS and provide a methodological blueprint for studying other vdW ferroelectrics.展开更多
This letter demonstrates an experimental approach to measuring the angular-momentum-resolved population of excited states in laser-produced argon ions.By measuring the spectra of free induction decay emissions corresp...This letter demonstrates an experimental approach to measuring the angular-momentum-resolved population of excited states in laser-produced argon ions.By measuring the spectra of free induction decay emissions corresponding to the resonant transitions between Rydberg states,the relative population of the Rydberg states is obtained with known Einstein A-coefficients.This study deepens the mechanistic understanding of coherent dynamics in laser-driven ionic excited states,and establishes experimental benchmarks essential for validating and refining advanced quantum kinetic models in strong-field physics.展开更多
文摘An effective approach for optimizing the rotor contour for variable reluctance(VR)resolver is presented.Using this approach,the procedure for optimizing the rotor is divided into two parts:the establishment of initial shape curve,and then computation for the optimization.In order to simplify the process of the former,a shape function is constructed.And the latter is carried out by Taguchi optimization method and finite element method(FEM).An example of a 3-10 VR resolver is used to present the procedure of the optimization,and the testing results confirmed the effectivity of the approach.
文摘The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of a resolver is approached. And a polyphase multipole resolver is developed in the brushless DC torque motor. Finally, the experimental results are presented to illustrate the improvement of ripple torque in the brushless DC torque motor with the polyphase multipole resolver.
文摘随着校园周边交通量的增加,交叉口的交通拥堵问题愈发严重,对行人和车辆的通行造成了较大困扰。为有效提高交叉口的通行效率,减少交通延误与排队长度,本文基于多元数据,利用Synchro交通仿真系统对校园周边的海棠路与丁香路交叉口进行了信号优化研究。通过对现状交通流量数据的收集与分析,建立交叉口的仿真模型,评估现有信号配时方案的不足之处。基于流量/容量比率(V/C ratio)、控制延误(Control Delay)和服务水平(LOS)等关键指标,对信号配时方案进行了调整与优化。优化后的信号配时方案显著降低了高峰期的排队长度,改善了各交通流向的通行效率,并提高了整体的服务水平。结果表明:燃料消耗由155升降低至105升,减少了约32%,优化效果明显;停车次数从1359次/小时减少至1121次/小时,降低了约17.5%;总延误时间从549.2秒缩短至520.1秒,减少了约5.3%;交叉口的总体服务水平由E提升为D。研究表明,基于多元数据的Synchro信号优化对缓解校园周边交叉口的交通拥堵、提高通行效率和道路安全具有重要作用。With the increasing traffic volume around campuses, congestion at intersections has become more severe, causing significant challenges for pedestrians and vehicles. To effectively improve the efficiency of intersection traffic flow and reduce delays and queue lengths, this study conducts a signal optimization analysis for the intersection of Haitang Road and Dingxiang Road near a campus, using the Synchro traffic simulation system and multi-source data. By collecting and analyzing the existing traffic flow data, a simulation model of the intersection was established to evaluate the shortcomings of the current signal timing plan. Based on key indicators such as volume-to-capacity ratio (V/C ratio), control delay, and level of service (LOS), adjustments and optimizations were made to the signal timing. The optimized signal timing plan significantly reduced queue lengths during peak hours, improved traffic flow efficiency across all directions, and enhanced the overall level of service. Results showed that fuel consumption was reduced from 155 liters to 105 liters, a decrease of approximately 32%;the number of stops decreased from 1359 stops/hour to 1121 stops/hour, reducing by about 17.5%;and total delay time was reduced from 549.2 seconds to 520.1 seconds, a decrease of approximately 5.3%. The overall level of service of the intersection was improved from E to D. The study indicates that Synchro signal optimization based on multi-source data plays a crucial role in alleviating congestion, enhancing traffic efficiency, and improving road safety at campus-area intersections.
文摘From October 30 to November 1,2025,Chinese President Xi Jinping traveled to the Republic of Korea(ROK)to attend the 32nd Asia-Pacific Economic Cooperation(APEC)Economic Leaders’Meeting and also pay a state visit to the country.This was Xi Jinping’s first overseas trip following the conclusion of the fourth plenary session of the 20th Communist Party of China Central Committee,underscoring its importance on China’s diplomatic agenda.
文摘In this paper,we study the nonlinear stability problem for the two-dimensional Boussinesq system around the Couette flow in a finite channel with Navier-slip boundary condition for the velocity and Dirichlet boundary condition for the temperature with small viscosityνand small thermal diffusionμ.We establish that if the initial perturbation velocity and initial perturbation temperature satisfy ||u_(0)||H^(2)≤ε_(0) min{μ,ν}1/2, and ||θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||H^(1)+|||D_(x)|^(1/3)θ_(0)||_(H^(1))≤εi min{μ,ν}^(5/6),for some smallε0 andε1 independent ofμ,ν,then the solution of the two-dimensional NavierStokes Boussinesq system does not transition away from the Couette flow for any time.
基金supported by the National Natural Science Foundation of China(NSFC)Basic Science Center Program for Multiscale Problems in Nonlinear Mechanics(Grant No.11988102).
文摘Nonlinear energy transfer is represented through eddy viscosity and stochastic forcing within the framework of resolvent analysis.Previous investigations estimate the contribution of eddy-viscosity-enhanced resolvent opera-tor to nonlinear energy transfer.The present article estimates the contribution of stochastic forcing to nonlinear energy transfer and demonstrates that the contribution of stochastic forcing cannot be ignored.These results are achieved by numerically comparing the eddy-viscosity-enhanced resolvent operator and stochastic forcing with nonlinear energy transfer in turbulent channel flows.Furthermore,the numerical results indicate that composite resolvent operators can improve the prediction of nonlinear energy transfer.
基金supported by the National Natural Science Foundation of China(No.22173012 and No.21773011).
文摘Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring these radicals in reactions and investigating their structure-reactivity effect.In this work,vibrationally resolved laser-induced fluorescence(LIF)spectrum of the 3-cyclohexyl-1-propoxy radical was obtained in supersonic jet condition.Low energy conformers G′_(1)T_(2)G_(3)and T_(1)T_(2)G_(3)were identified as the spectral carriers.A red shift of the spectrum compared to that of the straight chain alkoxy radical with same number of carbon atoms suggested that the cyclohexyl ring was a slightly better electron donor than the linear alkyl group.Studies also showed that theαandβC cyclohexyl substitutions significantly weakened theβC-C bonds of the radicals,and conversely,the strength of the C-C bonds on cyclohexyl ring decreased as its distance from the O radical decreased.When cyclohexyl substitution occurred atγC,the stability of the 3-cyclohexyl-1-propoxy radical became comparable to that of straight chain alkoxy radicals.
基金supported by the National Natural Science Foundation of China(Nos.62303271,U1806202,62103397)the Natural Science Foundation of Shandong Province(ZR2023QF081)Funding for open access charge:the National Natural Science Foundation of China(Nos.62303271,U1806202).
文摘Recent advances in spatially resolved transcriptomics(SRT)have provided new opportunities for characterizing spatial structures of various tissues.Graph-based geometric deep learning has gained widespread adoption for spatial domain identification tasks.Currently,most methods define adjacency relation between cells or spots by their spatial distance in SRT data,which overlooks key biological interactions like gene expression similarities,and leads to inaccuracies in spatial domain identification.To tackle this challenge,we propose a novel method,SpaGRA(https://github.com/sunxue-yy/SpaGRA),for automatic multi-relationship construction based on graph augmentation.SpaGRA uses spatial distance as prior knowledge and dynamically adjusts edge weights with multi-head graph attention networks(GATs).This helps SpaGRA to uncover diverse node relationships and enhance message passing in geometric contrastive learning.Additionally,SpaGRA uses these multi-view relationships to construct negative samples,addressing sampling bias posed by random selection.Experimental results show that SpaGRA presents superior domain identification performance on multiple datasets generated from different protocols.Using SpaGRA,we analyze the functional regions in the mouse hypothalamus,identify key genes related to heart development in mouse embryos,and observe cancer-associated fibroblasts enveloping cancer cells in the latest Visium HD data.Overall,SpaGRA can effectively characterize spatial structures across diverse SRT datasets.
基金supported by the Seventh Batch of National Academic Experience Inheritance Project for Senior TCM Experts from the National Administration of Traditional Chinese Medicine(No.GZYRJS[2022]76)the Sixth Batch of Beijing Municipal Academic Experience Inheritance Project for TCM Experts from Beijing Administration of Traditional Chinese Medicine(No.JZYKZ[2019]139).
文摘Granulomatosis with polyangiitis(GPA)poses significant therapeutic challenges due to its susceptibility to concurrent infections and frequent relapses.Professor SHI Zaixiang proposed the therapeutic theory of lifting depression and removing blood stasis,resolving phlegm and dispelling nodulation for GPA management.He identified the core pathogenesis as“Qi collapse with collateral obstruction and phlegm-stasis intermingling”,establishing the treatment principle of comprehensive intervention through ascending ancestral Qi,activating blood circulation,and resolving phlegm-stasis nodules.In clinical practice,Professor SHI emphasizes maintaining immune homeostasis with herbal medicine to enhance efficiency,while dynamically balancing Qi,blood,Yin,and Yang.Notably,he highlights the critical role of emotional factors in autoimmune disease progression.A representative case was provided to elucidate his clinical reasoning in GPA treatment.
基金Project supported by the National Natural Science Foundation of China(Grant No.12474181)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021B0301030002 and 2024A1515010656)the Guangdong Science and Technology Project(Grant No.2021QN02X859)。
文摘Silicene,a silicon analog of graphene,holds promise for next-generation electronics due to its tunable bandgap and larger spin-orbit coupling.Despite extensive efforts to synthesize and characterize silicene on metal substrates,bondresolved imaging of its atomic structure has remained elusive.Here,we report the fabrication and bond-resolved characterization of silicene on Au(111)substrate.Three silicene phases tuned by surface reconstruction and annealing temperatures are achieved.Using CO-terminated scanning tunneling microscopy(STM)tips,we resolve these silicene phases with atomic precision,determining their bond lengths,local strain,and geometric configurations.Furthermore,we correlate these structural features with their electronic properties,revealing the effect of strain and substrate interactions on the electronic properties of silicene.This work establishes silicene's intrinsic bonding topology and resolves longstanding controversies in silicene research.
文摘Photocatalysts show broad application potential in clean energy conversion by utilizing solar energy for chemical transformations[1–3].However,single-component photocatalysts are severely limited in practical applications due to narrow light absorption ranges and high recombination rates of photogenerated carriers[4].S-scheme heterojunctions preserve optimal redox potentials,offering broad application prospects in solar energy conversion and environmental remediation[5,6].Since photocatalytic reactions occur predominantly at the material interface,a spatially resolved investigation of charge transfer is essential for understanding carrier dynamics at the nanoscale[7].In this context,the highlighted study employs Kelvin probe force microscopy(KPFM)to elucidate the real-space charge-transfer mechanisms in CdS/BiOBr S-scheme heterojunctions,providing direct and quantitative insight into interfacial charge behavior[8].
基金supported by the National Natural Science Foundation of China(Grant Nos.12474089,12574102 for L.Y.and L.F.,and 12404102 for J.Z.)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions(for L.Y.and L.F.)+2 种基金the Natural Science Foundation of the Jiangsu Province(Grant No.BK20230806 for J.Z.)Southeast University Interdisciplinary Research Program for Young Scholars(Grant No.2024FGC1008 for J.Z.)the support by the State Key Laboratory of Solid State Microstructures(Nanjing University)(No.M37067)。
文摘The layered van der Waals(vdW)ferroelectric CuInP2S6(CIPS)exhibits unique cation-hopping-driven phenomena that bring about unconventional properties with intriguing mechanisms and hold promise for advanced applications in nanoelectronics.However,an explicit analysis of its lattice dynamics and vibrational symmetries,pivotal for understanding the material’s peculiar ferroelectric and ferroionic behaviors,remains incomplete.Here,we employ angle-resolved polarized Raman spectroscopy in concert with first-principles calculations to systematically unravel the anisotropic lattice vibrations of CIPS single crystals.By analyzing the polarization-dependent Raman intensities,we determine the symmetry assignments and Raman tensors of all major vibrational modes,revealing good agreement with theoretical predictions.Furthermore,we demonstrate the utility of Raman spectroscopy as a sensitive and non-invasive probe for structural and ferroelectric order evolution by examining temperature-driven phase transitions and thickness-dependent polarization suppression in CIPS.Our findings establish a foundational framework for correlating lattice dynamics with functional properties in CIPS and provide a methodological blueprint for studying other vdW ferroelectrics.
基金supported by the National Natural Science Foundation of China(Grant Nos.12234020,12474281,12450403,and 12274461)the Science and Technology Innovation Program of Hunan Province(Grant No.2022RC1193)。
文摘This letter demonstrates an experimental approach to measuring the angular-momentum-resolved population of excited states in laser-produced argon ions.By measuring the spectra of free induction decay emissions corresponding to the resonant transitions between Rydberg states,the relative population of the Rydberg states is obtained with known Einstein A-coefficients.This study deepens the mechanistic understanding of coherent dynamics in laser-driven ionic excited states,and establishes experimental benchmarks essential for validating and refining advanced quantum kinetic models in strong-field physics.
