The influence of electron-phonon interactions on third-harmonic generation in a square quantum well is investigated. The first- and third-harmonic generation coefficient is obtained by using compact-density-matrix app...The influence of electron-phonon interactions on third-harmonic generation in a square quantum well is investigated. The first- and third-harmonic generation coefficient is obtained by using compact-density-matrix approach and iterative method, and the numerical results are presented for a GaAs square quantum well. The results show that the third-harmonic generation coefficient is obviously enhanced after considering the influence of electron-phonon interactions.展开更多
Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of ...Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been calculated.The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained.展开更多
The photo-induced ultrafast electron dynamics in both anatase and rutile TiO_(2) are investigated by using the Boltzmann transport equation with the explicit incorporation of electron-phonon scattering rates.All struc...The photo-induced ultrafast electron dynamics in both anatase and rutile TiO_(2) are investigated by using the Boltzmann transport equation with the explicit incorporation of electron-phonon scattering rates.All structural parameters required for dynamic simulations are obtained from ab initio calculations.The results show that although the longitudinal optical modes significantly affect the electron energy relaxation dynamics in both phases due to strong Fr?hlich-type couplings,the detailed relaxation mechanisms have obvious differences.In the case of a single band,the energy relaxation time in anatase is 24.0 fs,twice longer than 11.8 fs in rutile.This discrepancy is explained by the different diffusion distributions over the electronic Bloch states and different scattering contributions from acoustic modes in the two phases.As for the multiple-band situation involving the lowest six conduction bands,the predicted overall relaxation times are about 47 fs and 57 fs in anatase and rutile,respectively,very different from the case of the single band.The slower relaxation in rutile is attributed to the existence of multiple rate-controlled steps during the dynamic process.The present findings may be helpful to control the electron dynamics for designing efficient TiO_(2)-based devices.展开更多
The electron-phonon interaction influences on lineax and nonfineax optical absorption in cylindrical quantum wires （CQW） with an infinite confining potential axe investigated. The optical absorption coefficients are...The electron-phonon interaction influences on lineax and nonfineax optical absorption in cylindrical quantum wires （CQW） with an infinite confining potential axe investigated. The optical absorption coefficients are obtained by using the compact-density-matrix approach and iterative method, and the numerical results are presented for GaAs CQW. The results show that the electron-phonon interaction makes a distinct influence on optical absorption in CQW. The electron-phonon interaction on the wave functions of electron dominates the values of absorption coefficients and the correction of the electron-phonon effect on the energies of the electron makes the absorption peaks blue shift and become wider. Moreover, the electron-phonon interaction influence on optical absorption with an infinite confining potential is different from that with a finite confining potential.展开更多
The confined longitudinal-optical （LO） phonon and surface-optical （SO） phonon modes of a free-standing annular cylindrical quantum dot are derived within the framework of dielectric continuum approximation. It is ...The confined longitudinal-optical （LO） phonon and surface-optical （SO） phonon modes of a free-standing annular cylindrical quantum dot are derived within the framework of dielectric continuum approximation. It is found that there exist two types of SO phonon modes： top SO （TSO） mode and side SO（SSO） mode in a cylindrical quantum annulus. Numerical calculation on CdS annulus system has been performed. Results reveal that the two different solutions of SSO mode distribute mainly at the inner or outer surfaces of the annulus. The dispersion relations and the coupling intensions of phonons in a quantum annulus are compared with those in a cylindrical quantum dot. It is found that the dispersion relations of the two different structures are similar, but the coupling intension of the phonon-electron interaction in quantum annulus is larger than that in quantum dot. The Hamiltonians describing the free phonon modes and their interactions with electrons in the system are also derived.展开更多
Using an expression of optical conductivity,based on the linear response theory,the Green's function technique and within the Holstein Hamiltonian model,the effect of electron-phonon interaction on the optical con...Using an expression of optical conductivity,based on the linear response theory,the Green's function technique and within the Holstein Hamiltonian model,the effect of electron-phonon interaction on the optical conductivity of graphene plane is studied.It is found that the electron-phonon coupling increases the optical conductivity of graphene sheet in the low frequency region due to decreasing quasiparticle weight of electron excitation while the optical conductivity reduces in the high frequency region.The latter is due to role of electrical field's frequency.展开更多
XB_(2)(X=Mg and Al)compounds have drawn great attention for their superior electronic characteristics and potential applications in semiconductors and superconductors.The study of phonon thermal transport properties o...XB_(2)(X=Mg and Al)compounds have drawn great attention for their superior electronic characteristics and potential applications in semiconductors and superconductors.The study of phonon thermal transport properties of XB_(2)is significant to their application and mechanism behind research.In this work,the phonon thermal transport properties of three-dimensional(3D)and two-dimensional(2D)XB_(2)were studied by first-principles calculations.After considering the electron-phonon interaction(EPI),the thermal conductivities(TCs)of 3D Mg B_(2)and 3D Al B_(2)decrease by 29%and 16%which is consistent with experimental values.Moreover,the underlying mechanisms of reduction on lattice TCs are the decrease in phonon lifetime and heat capacity when considering quantum confinement effect.More importantly,we are surprised to find that there is a correlation between quantum confinement effect and EPI.The quantum confinement will change the phonon and electron characteristics which has an impact on EPI.Overall,our work is expected to provide insights into the phonon thermal transport properties of XB_(2)compounds considering EPI and quantum confinement effect.展开更多
By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shift （PS） and the PS due to electron-phonon interaction （EPI） of R-line of MgO：Cr^3＋ have been calculated, respectively. The ca...By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shift （PS） and the PS due to electron-phonon interaction （EPI） of R-line of MgO：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. The behaviors of the pure electronic PS of R-line of MgO：Cr^3＋ and the PS of its R-line due to EPI are different. It is the combined effect of them that gives rise to the total PS of R-line, which has satisfactorily explained the experimental results. The comparison between the feature of R-line PS of MgO：Cr^3＋ and that of R1-line PS of ruby has been made.展开更多
Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electro...Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electron-PR phonons interaction in an asymmetrical wurtzite quantum well （QW） are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculation on an asymmetrical Alo.25Gao.75N/GaN/Alo.15Gao.ssN wurtzite QW were performed. The results reveal that there are infinite branches of PR phonon modes in the systems. The behaviors of frequency forbidden of PR modes in the asymmetric QWs have been clearly observed. The mathematical and physical origins for these features have been analyzed in depth. The PR optical phonon branches have been distinguished and labelled reasonably in terms of the oscillating properties of the PR modes in the well-layer material. Moreover, the amplitudes and frequency properties of the electron-PR modes coupling functions in the barrier and well materials have also been analyzed from both of the mathematical and physical viewpoints.展开更多
The effects of electron-phonon interaction have to be taken into account for the physical process in a small system of condensed matters.The electron-phonon interaction in a I-D finite lattice system has been analyzed...The effects of electron-phonon interaction have to be taken into account for the physical process in a small system of condensed matters.The electron-phonon interaction in a I-D finite lattice system has been analyzed.The relation between the electron-phonon interaction and the symmetric properties of electronic states and phonons are considered,the transition probabilities are discussed.展开更多
We present our theoretical investigations on the effects of disorder on the electron-phonon interaction in semiconducting GaAs system. Both the temperature (T) and disorder (electron mean free path l) dependences of t...We present our theoretical investigations on the effects of disorder on the electron-phonon interaction in semiconducting GaAs system. Both the temperature (T) and disorder (electron mean free path l) dependences of the electron-phonon scattering rate have been determined. On consideration of the dynamic screening, we find a significant change in the temperature exponent as well as the pre factor from the earlier reported temperature power law dependence result ?T6 obtained under static screening. Also the dynamic screening makes a noticeable change in the character of the dependence of scattering rate on the mean free path from the static screening result.展开更多
As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises s...As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises structural concerns,and the latter is of aerodynamic interest.Thus,panel aeroelasticity in shock-dominated flow represents a vital topic for the development and optimization of supersonic vehicles and propulsion systems.This review systematically summarizes recent advances in the methodologies applied to capture structural and fluid dynamics,including theoretical models,numerical simulations,and wind tunnel experiments.The application of data-driven modal decomposition,an advanced technique to extract physically crucial features,on the topic is introduced.From the perspective of FSIs,the distinctive aeroelastic behaviors in shock-dominated flow,including hysteresis phenomena and nonlinear responses,are highlighted.From the perspective of SBLIs,the modifications in their spatial and temporal characteristics imposed by the aeroelastic responses are emphasized.Motivated by the interaction between the shock waves and structural response,different strategies have been proposed to implement aeroelastic suppression and shock control,which have the potential to enhance structural safety and aerodynamic performance in the next generation of high-speed flight vehicles.展开更多
This study reveals the critical role of multiscale interaction within the westerly wind bursts(WWBs)west of the MJO convection in modulating the prediction skill for the November MJO event during the DYNAMO(Dynamics o...This study reveals the critical role of multiscale interaction within the westerly wind bursts(WWBs)west of the MJO convection in modulating the prediction skill for the November MJO event during the DYNAMO(Dynamics of the Madden–Julian Oscillation)field campaign.The characteristics of the MJO convection envelope are obtained by the largescale precipitation tracking method,and a novel metric is introduced to quantify the prediction skill for the MJO convection in the ECMWF reforecast.The ECMWF forecast exhibits approximately 17 days in skillful prediction for the MJO convection—significantly lower than that derived from the global measure.The reforecast ensembles are further classified into high and low skill catalogs based on the mean prediction skill during the observed WWBs period.High-skill ensembles exhibit significantly enhanced low-level westerlies,amplified MJO convection,and reduced spatial separation between the low-level westerlies and MJO convection during the WWBs period,indicating stronger coupling between the large-scale circulation and the convection.Mechanistic analysis reveals that enhanced westerlies in high-skill ensembles can transfer more high-frequency energy to the MJO convection through the flux convergence of interaction energy for MJO convection development,resulting in better prediction skill.展开更多
Cytochrome c(cyt c)is released from mitochondria into the cytosol upon apoptotic stimulation,ultimately triggering programmed cell death.Recent studies have revealed that transfer RNA(tRNA)interacts with cyt c,impedin...Cytochrome c(cyt c)is released from mitochondria into the cytosol upon apoptotic stimulation,ultimately triggering programmed cell death.Recent studies have revealed that transfer RNA(tRNA)interacts with cyt c,impeding the formation of the apoptosome complex and thereby suppressing apoptosis.To elucidate the molecular mechanism underlying the interaction between cyt c and tRNA,nuclear magnetic resonance(NMR)-based chemical shift perturbation and intensity analysis were employed to characterize the binding interface between cyt c and tRNAphe.The findings demonstrate that cyt c primarily engages with tRNAphe through its 70–85Ω-loop and N-terminalα-helix.This interaction sterically hinders the accessibility of small molecules,such as H_(2)O_(2),to the hydrophobic pocket of cyt c,consequently attenuating its peroxidase activity.Furthermore,oxidative modification of cyt c,particularly the carbonylation of positively charged lysine residues,weakens this interaction.展开更多
Using observational and reanalysis datasets,this study explores the mechanisms by which the interactions among multi-timescale flows impacted the onset of rapid intensification(RI)of Typhoon Hato(2017).Hato(2017)forme...Using observational and reanalysis datasets,this study explores the mechanisms by which the interactions among multi-timescale flows impacted the onset of rapid intensification(RI)of Typhoon Hato(2017).Hato(2017)formed within a northwest–southeast-oriented synoptic-scale(with periods<10 days)wave train,concurring with a developing intraseasonal(10–90 days)oscillation and an elongated low-frequency(>90 days)monsoon trough in the western North Pacific.Impacted by continuously increasing vertical wind shear,the TC long maintained a highly asymmetric convective structure.Prior to RI onset,the synoptic-scale circulation and the inner-core asymmetric convection of Hato(2017)greatly strengthened,which are the key factors believed to trigger RI.A multi-timescale eddy kinetic energy budget indicates that the wind convergence associated with the intraseasonal circulation and monsoon trough led to barotropic energy conversion that largely enhanced the synoptic-scale cyclonic circulation.Besides,the pronounced increases in midlevel relative humidity(RH)and surface latent heat flux(LHF)were observed upshear before RI onset,which were primarily driven by the strong intraseasonal and synoptic-scale RH anomalies and the strengthened low-level wind speed,respectively.The increased LHF and midlevel RH,together with the enhanced downshear confluence between synoptic-scale and Intraseasonal Oscillation(ISO)/low-frequency winds,could have helped the intensification of asymmetric convection that supports RI onset.Overall,this study suggests that the interactions across multiple timescales may create favorable dynamic and thermodynamic conditions that promoted RI onset,offering new insights into RI processes for highly asymmetric tropical cyclones like Hato(2017).展开更多
Existing quantitative trait locus(QTL)mapping had low efficiency in identifying small-effect and closely linked QTL-by-environment interactions(QEIs)in recombinant inbred lines(RILs),especially in the era of global cl...Existing quantitative trait locus(QTL)mapping had low efficiency in identifying small-effect and closely linked QTL-by-environment interactions(QEIs)in recombinant inbred lines(RILs),especially in the era of global climate change.To address this challenge,here we integrate the compressed variance component mixed model with our GCIM to propose 3vGCIM for identifying QEIs in RILs,and extend 3vGCIM-random to 3vGCIM-fixed.3vGCIM integrates genome-wide scanning with machine learning,significantly improving power.In the mixed full model,we consider all possible effects and control for all possible polygenic backgrounds.In simulation studies,3vGCIM exhibits higher power(∼92.00%),higher accuracy of the estimates for QTL position(∼1.900 cM2)and effect(∼0.050),and lower false positive rate(∼0.48‰)and false negative rate(<8.10%)in three environments of 300 RILs each than ICIM(47.57%;3.607 cM2,0.583;2.81‰;52.43%)and MCIM(60.30%;5.279 cM2,0.274;2.17‰;39.70%).In the real data analysis of rice yield-related traits in 240 RILs,3vGCIM mines more known genes(57–60)and known gene-by-environment interactions(GEIs)(14–19)and candidate GEIs(21–23)than ICIM(27,2,and 7),and MCIM(21,1,and 3),especially in small-effect and linked QTLs and QEIs.This makes 3vGCIM a powerful and sensitive tool for QTL mapping and molecular QTL mapping.展开更多
The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration...The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.展开更多
Existing rehabilitation exoskeleton robots suffer from poor compatibility with the human limb coupling method,large internal power loss,and poor wearable performance,which seriously affect the rehabilitation ability o...Existing rehabilitation exoskeleton robots suffer from poor compatibility with the human limb coupling method,large internal power loss,and poor wearable performance,which seriously affect the rehabilitation ability of these robots.Therefore,this study proposes a variable stiffness humancomputer interaction contact unit module(VSHCUM)based on the granular jamming mechanism.It is characterized by a double-layer chamber structure:the inner layer is a granular chamber,and the outer layer is an air chamber.The interaction force is transmitted by embedding a rigid support in the inner layer.Unlike the common flexible-belt interactive contact unit,when the exoskeleton is bound to the patient's limb,vSHCUM can realize adaptive fitting of the patient's limb shape using the pressure change in the double-chamber structure.Simultaneously,by adjusting the vacuum level of the granular chamber,the stiffness of the interactive contact unit can be adjusted by a factor of more than five,and the internal work loss caused by self-pulling deformation during the auxiliary force transfer process can be reduced.展开更多
The antioxidant activity of selenium-containing soybean peptides(SePPs)has been previously demonstrated,despite their limited absorption in the small intestine.This study investigates the antioxidant mechanism of a se...The antioxidant activity of selenium-containing soybean peptides(SePPs)has been previously demonstrated,despite their limited absorption in the small intestine.This study investigates the antioxidant mechanism of a selenium-containing tetrapeptide,Ser-Phe-Gln-SeM(SFQSeM),identified from SePPs,with particular emphasis on its interaction with the intestinal microbiota and its role in modulating host antioxidant defenses.The effects of SFQSeM were evaluated in a D-galactose-induced oxidative stress model and an antibiotictreated mouse model.SFQSeM supplementation significantly reduced the oxidative stress in D-galactosetreated mice.It also promoted the growth of beneficial bacteria and increased the levels of acetate,butyrate and lactate in the intestine(P<0.05).In the antibiotic-treated mouse model,depletion of the intestinal microbiota significantly reduced hepatic glutathione peroxidase(GSH-Px)activity(26.6%)and glutathione peroxidase 1(GPx-1)expression(48.77%)compared to normal mice supplemented with SFQSeM(P<0.05).In contrast to Na_(2)SeO_(3)and selenomethionine,SFQSeM effectively restored the diversity of the intestinal microbiota disrupted by antibiotics.Lactobacillus,Lachnospiraceae_NK4A136_group,and Muribaculaceae were identified as predominant bacteria in the SFQSeM group,and were strongly associated with increased hepatic GSH-Px activity and GPx-1 mRNA expression(P<0.05).In conclusion,intestinal microbiota enhances the antioxidant efficacy of SFQSeM by modulating microbial composition,producing active metabolites,and converting SFQSeM into a bioactive form of selenium.展开更多
Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudst...Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudstone subjected to THM interactions were investigated by triaxial tests.The underlying micro-mechanisms were revealed using microscopic tests.The triaxial test results indicate that the strength parameters of silty mudstone decrease by 89.50%(deformation modulus),78.15%(peak strength),70.58%(cohesion),and 48.65%(friction angle)under 16 THM cycles,a load of 300 kPa,and alternating between 0℃water immersion and 60℃drying.The SEM test results indicate that the deterioration of silty mudstone strength primarily results from hydrothermal-expansion softening and cracking driven by the TLHM interactions.The specimens manifest shear failure under confining pressure exceeding 140 kPa.Furthermore,a new constitutive model considering hydrothermalexpansion strain and non-linear deformation characteristics was developed.The discrepancy between the experimentally measured peak strength and the damage constitutive model prediction remains below 5%.The proposed model is verified to be in satisfactory agreement with the experimental results.The self-designed THM apparatus overcomes the limitations of traditional investigations,enabling simultaneous consideration of thermal,hydraulic,and mechanical interactions.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 60478010, the Science and Technology Committee of Guangdong Province of China under Grant Nos. 2004B10301014 and 04105406, Science and Technology Bureau of Guangzhou under Grant Nos. 200J1-C0031 and 2004J1-C0226, and Education Bureau of Guangzhou under Grant No. 2024
文摘The influence of electron-phonon interactions on third-harmonic generation in a square quantum well is investigated. The first- and third-harmonic generation coefficient is obtained by using compact-density-matrix approach and iterative method, and the numerical results are presented for a GaAs square quantum well. The results show that the third-harmonic generation coefficient is obviously enhanced after considering the influence of electron-phonon interactions.
文摘Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been calculated.The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained.
基金supported by the National Natural Science Foundation of China(No.22033006,No.21833006 and No.21773191)。
文摘The photo-induced ultrafast electron dynamics in both anatase and rutile TiO_(2) are investigated by using the Boltzmann transport equation with the explicit incorporation of electron-phonon scattering rates.All structural parameters required for dynamic simulations are obtained from ab initio calculations.The results show that although the longitudinal optical modes significantly affect the electron energy relaxation dynamics in both phases due to strong Fr?hlich-type couplings,the detailed relaxation mechanisms have obvious differences.In the case of a single band,the energy relaxation time in anatase is 24.0 fs,twice longer than 11.8 fs in rutile.This discrepancy is explained by the different diffusion distributions over the electronic Bloch states and different scattering contributions from acoustic modes in the two phases.As for the multiple-band situation involving the lowest six conduction bands,the predicted overall relaxation times are about 47 fs and 57 fs in anatase and rutile,respectively,very different from the case of the single band.The slower relaxation in rutile is attributed to the existence of multiple rate-controlled steps during the dynamic process.The present findings may be helpful to control the electron dynamics for designing efficient TiO_(2)-based devices.
基金Scientific Research Fired of the Education Department of Zhejiang Province of China
文摘The electron-phonon interaction influences on lineax and nonfineax optical absorption in cylindrical quantum wires （CQW） with an infinite confining potential axe investigated. The optical absorption coefficients are obtained by using the compact-density-matrix approach and iterative method, and the numerical results are presented for GaAs CQW. The results show that the electron-phonon interaction makes a distinct influence on optical absorption in CQW. The electron-phonon interaction on the wave functions of electron dominates the values of absorption coefficients and the correction of the electron-phonon effect on the energies of the electron makes the absorption peaks blue shift and become wider. Moreover, the electron-phonon interaction influence on optical absorption with an infinite confining potential is different from that with a finite confining potential.
基金the Scientific and Technology Project of Guangzhou Municipal Government under Grant No.2004J1-C0327
文摘The confined longitudinal-optical （LO） phonon and surface-optical （SO） phonon modes of a free-standing annular cylindrical quantum dot are derived within the framework of dielectric continuum approximation. It is found that there exist two types of SO phonon modes： top SO （TSO） mode and side SO（SSO） mode in a cylindrical quantum annulus. Numerical calculation on CdS annulus system has been performed. Results reveal that the two different solutions of SSO mode distribute mainly at the inner or outer surfaces of the annulus. The dispersion relations and the coupling intensions of phonons in a quantum annulus are compared with those in a cylindrical quantum dot. It is found that the dispersion relations of the two different structures are similar, but the coupling intension of the phonon-electron interaction in quantum annulus is larger than that in quantum dot. The Hamiltonians describing the free phonon modes and their interactions with electrons in the system are also derived.
文摘Using an expression of optical conductivity,based on the linear response theory,the Green's function technique and within the Holstein Hamiltonian model,the effect of electron-phonon interaction on the optical conductivity of graphene plane is studied.It is found that the electron-phonon coupling increases the optical conductivity of graphene sheet in the low frequency region due to decreasing quasiparticle weight of electron excitation while the optical conductivity reduces in the high frequency region.The latter is due to role of electrical field's frequency.
基金financially supported by the National Natural Science Foundation of China(Nos.51720105007,52076031 and 51806031)the Fundamental Research Funds for the Central Universities(No.DUT19RC(3)006)the computing resources from Super-computing Center of Dalian University of Technology。
文摘XB_(2)(X=Mg and Al)compounds have drawn great attention for their superior electronic characteristics and potential applications in semiconductors and superconductors.The study of phonon thermal transport properties of XB_(2)is significant to their application and mechanism behind research.In this work,the phonon thermal transport properties of three-dimensional(3D)and two-dimensional(2D)XB_(2)were studied by first-principles calculations.After considering the electron-phonon interaction(EPI),the thermal conductivities(TCs)of 3D Mg B_(2)and 3D Al B_(2)decrease by 29%and 16%which is consistent with experimental values.Moreover,the underlying mechanisms of reduction on lattice TCs are the decrease in phonon lifetime and heat capacity when considering quantum confinement effect.More importantly,we are surprised to find that there is a correlation between quantum confinement effect and EPI.The quantum confinement will change the phonon and electron characteristics which has an impact on EPI.Overall,our work is expected to provide insights into the phonon thermal transport properties of XB_(2)compounds considering EPI and quantum confinement effect.
文摘By means of improved ligand-field theory, the ＂pure electronic＂ pressure-induced shift （PS） and the PS due to electron-phonon interaction （EPI） of R-line of MgO：Cr^3＋ have been calculated, respectively. The calculated results are in very good agreement with the experimental data. The behaviors of the pure electronic PS of R-line of MgO：Cr^3＋ and the PS of its R-line due to EPI are different. It is the combined effect of them that gives rise to the total PS of R-line, which has satisfactorily explained the experimental results. The comparison between the feature of R-line PS of MgO：Cr^3＋ and that of R1-line PS of ruby has been made.
基金The project supported by the Science and Technology Project of Adwnced Academy of Guangzhou City under Grant No. 2060, National Natural Science Foundation of China under Grant Nos. 60276004 and 60390073, and the Scientific Research Foundation for the Returned 0verseas Chinese Scholars of the Ministry of Education of China
文摘Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electron-PR phonons interaction in an asymmetrical wurtzite quantum well （QW） are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculation on an asymmetrical Alo.25Gao.75N/GaN/Alo.15Gao.ssN wurtzite QW were performed. The results reveal that there are infinite branches of PR phonon modes in the systems. The behaviors of frequency forbidden of PR modes in the asymmetric QWs have been clearly observed. The mathematical and physical origins for these features have been analyzed in depth. The PR optical phonon branches have been distinguished and labelled reasonably in terms of the oscillating properties of the PR modes in the well-layer material. Moreover, the amplitudes and frequency properties of the electron-PR modes coupling functions in the barrier and well materials have also been analyzed from both of the mathematical and physical viewpoints.
文摘The effects of electron-phonon interaction have to be taken into account for the physical process in a small system of condensed matters.The electron-phonon interaction in a I-D finite lattice system has been analyzed.The relation between the electron-phonon interaction and the symmetric properties of electronic states and phonons are considered,the transition probabilities are discussed.
文摘We present our theoretical investigations on the effects of disorder on the electron-phonon interaction in semiconducting GaAs system. Both the temperature (T) and disorder (electron mean free path l) dependences of the electron-phonon scattering rate have been determined. On consideration of the dynamic screening, we find a significant change in the temperature exponent as well as the pre factor from the earlier reported temperature power law dependence result ?T6 obtained under static screening. Also the dynamic screening makes a noticeable change in the character of the dependence of scattering rate on the mean free path from the static screening result.
基金supported by the National Natural Science Foundation of China(No.12372233)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.25GH01020005)the“111 Project”of China(No.B17037)。
文摘As a multidisciplinary phenomenon,panel aeroelasticity in shock-dominated flow is featured by two primary interactions:Fluid-Structure Interactions(FSIs)and Shock-Boundary Layer Interactions(SBLIs).The former raises structural concerns,and the latter is of aerodynamic interest.Thus,panel aeroelasticity in shock-dominated flow represents a vital topic for the development and optimization of supersonic vehicles and propulsion systems.This review systematically summarizes recent advances in the methodologies applied to capture structural and fluid dynamics,including theoretical models,numerical simulations,and wind tunnel experiments.The application of data-driven modal decomposition,an advanced technique to extract physically crucial features,on the topic is introduced.From the perspective of FSIs,the distinctive aeroelastic behaviors in shock-dominated flow,including hysteresis phenomena and nonlinear responses,are highlighted.From the perspective of SBLIs,the modifications in their spatial and temporal characteristics imposed by the aeroelastic responses are emphasized.Motivated by the interaction between the shock waves and structural response,different strategies have been proposed to implement aeroelastic suppression and shock control,which have the potential to enhance structural safety and aerodynamic performance in the next generation of high-speed flight vehicles.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.U2442206,42205067,and 41922035)the National Key R&D Program of China(Grant No.2024YFC3013100)the Key Research Program of Frontier Sciences of CAS(Grant No.QYZDB-SSW-DQC017).
文摘This study reveals the critical role of multiscale interaction within the westerly wind bursts(WWBs)west of the MJO convection in modulating the prediction skill for the November MJO event during the DYNAMO(Dynamics of the Madden–Julian Oscillation)field campaign.The characteristics of the MJO convection envelope are obtained by the largescale precipitation tracking method,and a novel metric is introduced to quantify the prediction skill for the MJO convection in the ECMWF reforecast.The ECMWF forecast exhibits approximately 17 days in skillful prediction for the MJO convection—significantly lower than that derived from the global measure.The reforecast ensembles are further classified into high and low skill catalogs based on the mean prediction skill during the observed WWBs period.High-skill ensembles exhibit significantly enhanced low-level westerlies,amplified MJO convection,and reduced spatial separation between the low-level westerlies and MJO convection during the WWBs period,indicating stronger coupling between the large-scale circulation and the convection.Mechanistic analysis reveals that enhanced westerlies in high-skill ensembles can transfer more high-frequency energy to the MJO convection through the flux convergence of interaction energy for MJO convection development,resulting in better prediction skill.
基金financial support from National Key R&D Program of China(2018YFA0704002,2018YFE0202300,2023YFA1607500)National Natural Science Foundation of China(22174152,21991081,2204167,21505153,21675170,2147514621735007,and 22204167)+2 种基金Hubei Provincial Natural Science Foundation of China(2023AFA041)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0540300)Funding of Wuhan Special Project for Knowledge Innovation(2023020201010085).
文摘Cytochrome c(cyt c)is released from mitochondria into the cytosol upon apoptotic stimulation,ultimately triggering programmed cell death.Recent studies have revealed that transfer RNA(tRNA)interacts with cyt c,impeding the formation of the apoptosome complex and thereby suppressing apoptosis.To elucidate the molecular mechanism underlying the interaction between cyt c and tRNA,nuclear magnetic resonance(NMR)-based chemical shift perturbation and intensity analysis were employed to characterize the binding interface between cyt c and tRNAphe.The findings demonstrate that cyt c primarily engages with tRNAphe through its 70–85Ω-loop and N-terminalα-helix.This interaction sterically hinders the accessibility of small molecules,such as H_(2)O_(2),to the hydrophobic pocket of cyt c,consequently attenuating its peroxidase activity.Furthermore,oxidative modification of cyt c,particularly the carbonylation of positively charged lysine residues,weakens this interaction.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFF0807000)supported by the National Natural Science Foundation of China(Grant Nos.42305004,42175073 and 42175013)supported partly by the China Postdoctoral Science Foundation(Grant No.2023M743283).
文摘Using observational and reanalysis datasets,this study explores the mechanisms by which the interactions among multi-timescale flows impacted the onset of rapid intensification(RI)of Typhoon Hato(2017).Hato(2017)formed within a northwest–southeast-oriented synoptic-scale(with periods<10 days)wave train,concurring with a developing intraseasonal(10–90 days)oscillation and an elongated low-frequency(>90 days)monsoon trough in the western North Pacific.Impacted by continuously increasing vertical wind shear,the TC long maintained a highly asymmetric convective structure.Prior to RI onset,the synoptic-scale circulation and the inner-core asymmetric convection of Hato(2017)greatly strengthened,which are the key factors believed to trigger RI.A multi-timescale eddy kinetic energy budget indicates that the wind convergence associated with the intraseasonal circulation and monsoon trough led to barotropic energy conversion that largely enhanced the synoptic-scale cyclonic circulation.Besides,the pronounced increases in midlevel relative humidity(RH)and surface latent heat flux(LHF)were observed upshear before RI onset,which were primarily driven by the strong intraseasonal and synoptic-scale RH anomalies and the strengthened low-level wind speed,respectively.The increased LHF and midlevel RH,together with the enhanced downshear confluence between synoptic-scale and Intraseasonal Oscillation(ISO)/low-frequency winds,could have helped the intensification of asymmetric convection that supports RI onset.Overall,this study suggests that the interactions across multiple timescales may create favorable dynamic and thermodynamic conditions that promoted RI onset,offering new insights into RI processes for highly asymmetric tropical cyclones like Hato(2017).
基金supported by the National Natural Science Foundation of China(32270673 and 32470657).
文摘Existing quantitative trait locus(QTL)mapping had low efficiency in identifying small-effect and closely linked QTL-by-environment interactions(QEIs)in recombinant inbred lines(RILs),especially in the era of global climate change.To address this challenge,here we integrate the compressed variance component mixed model with our GCIM to propose 3vGCIM for identifying QEIs in RILs,and extend 3vGCIM-random to 3vGCIM-fixed.3vGCIM integrates genome-wide scanning with machine learning,significantly improving power.In the mixed full model,we consider all possible effects and control for all possible polygenic backgrounds.In simulation studies,3vGCIM exhibits higher power(∼92.00%),higher accuracy of the estimates for QTL position(∼1.900 cM2)and effect(∼0.050),and lower false positive rate(∼0.48‰)and false negative rate(<8.10%)in three environments of 300 RILs each than ICIM(47.57%;3.607 cM2,0.583;2.81‰;52.43%)and MCIM(60.30%;5.279 cM2,0.274;2.17‰;39.70%).In the real data analysis of rice yield-related traits in 240 RILs,3vGCIM mines more known genes(57–60)and known gene-by-environment interactions(GEIs)(14–19)and candidate GEIs(21–23)than ICIM(27,2,and 7),and MCIM(21,1,and 3),especially in small-effect and linked QTLs and QEIs.This makes 3vGCIM a powerful and sensitive tool for QTL mapping and molecular QTL mapping.
基金supported by the National Key Laboratory of Helicopter Aeromechanics Fund(No.2024-CXPT-GF-JJ-093-05).
文摘The complex aerodynamic interaction between tandem tilt-wing and multi-rotor directly affects the wing surface flow and rotor thrust,making it a critical factor during the tilt transition process of this configuration of rotorcraft.The aerodynamic interaction of tandem tilt-wing and multi-rotor is investigated based on the CFD method.The aerodynamic effect of multi tilt-rotor is simulated as virtual disk modeling by adding source terms to the Navier-Stokes equations,effectively reducing the calculation time while maintaining the accuracy of aerodynamic interaction calculations.Aerodynamic forces and flow field characteristics of the tandem tilt-wing and multi-rotor under different tilt angles are compared between cases with and without aerodynamic interaction.Furthermore,the differences in aerodynamic forces between dynamic tilt transition and fixed-angle conditions were compared.The results show that the aerodynamic interaction of multi-rotor obviously increases the lift of front tilt-wing at different tilt angles,the wing lift under interaction is increased by more than 40%compared with isolated wing at tilt angle of 15°for the computation in this paper,which is related to the increase of wing flow velocity and the suppression of flow separation caused by multi-rotor;the wing blocking effect will increase rotor thrust,especially near the tilt angles of 30°and 45°;the increases of rear wing lift and rear rotor thrust under aerodynamic interaction are not significant because of suppression by the front wing’s downwash;the unsteady effects during dynamic tilting have a relatively minor impact on aerodynamic interaction,with the aerodynamic forces on the rotors and wings during the dynamic tilting process showing little difference from those under corresponding fixed tilt angles.
基金Supported by National Key R&D Program of China(Grant Nos.2022YFC3601704,2023YFB4706100)National Natural Science Foundation of China(Grant Nos.U23A20338,62203149).
文摘Existing rehabilitation exoskeleton robots suffer from poor compatibility with the human limb coupling method,large internal power loss,and poor wearable performance,which seriously affect the rehabilitation ability of these robots.Therefore,this study proposes a variable stiffness humancomputer interaction contact unit module(VSHCUM)based on the granular jamming mechanism.It is characterized by a double-layer chamber structure:the inner layer is a granular chamber,and the outer layer is an air chamber.The interaction force is transmitted by embedding a rigid support in the inner layer.Unlike the common flexible-belt interactive contact unit,when the exoskeleton is bound to the patient's limb,vSHCUM can realize adaptive fitting of the patient's limb shape using the pressure change in the double-chamber structure.Simultaneously,by adjusting the vacuum level of the granular chamber,the stiffness of the interactive contact unit can be adjusted by a factor of more than five,and the internal work loss caused by self-pulling deformation during the auxiliary force transfer process can be reduced.
基金Financial support from the National Natural Science Foundation of China(32502106)One health Interdisciplinary Research Project,Institute of One Health Science,Ningbo University(NBUOH202502)the Ningbo Top Talent Project(215-432094250).
文摘The antioxidant activity of selenium-containing soybean peptides(SePPs)has been previously demonstrated,despite their limited absorption in the small intestine.This study investigates the antioxidant mechanism of a selenium-containing tetrapeptide,Ser-Phe-Gln-SeM(SFQSeM),identified from SePPs,with particular emphasis on its interaction with the intestinal microbiota and its role in modulating host antioxidant defenses.The effects of SFQSeM were evaluated in a D-galactose-induced oxidative stress model and an antibiotictreated mouse model.SFQSeM supplementation significantly reduced the oxidative stress in D-galactosetreated mice.It also promoted the growth of beneficial bacteria and increased the levels of acetate,butyrate and lactate in the intestine(P<0.05).In the antibiotic-treated mouse model,depletion of the intestinal microbiota significantly reduced hepatic glutathione peroxidase(GSH-Px)activity(26.6%)and glutathione peroxidase 1(GPx-1)expression(48.77%)compared to normal mice supplemented with SFQSeM(P<0.05).In contrast to Na_(2)SeO_(3)and selenomethionine,SFQSeM effectively restored the diversity of the intestinal microbiota disrupted by antibiotics.Lactobacillus,Lachnospiraceae_NK4A136_group,and Muribaculaceae were identified as predominant bacteria in the SFQSeM group,and were strongly associated with increased hepatic GSH-Px activity and GPx-1 mRNA expression(P<0.05).In conclusion,intestinal microbiota enhances the antioxidant efficacy of SFQSeM by modulating microbial composition,producing active metabolites,and converting SFQSeM into a bioactive form of selenium.
基金supported by“the National Natural Science Foundation of China(52378440,52078067,52078066,42477143,52408458)the Key Science and Technology Program in the Transportation Industry(2022-MS1-032,2022-MS5-125)+4 种基金the Natural Science Foundation of Hunan Province(2023JJ10045)the Outstanding Innovative Youth Training Program of Changsha City(kq2305023)Scientific Research Foundation of Hunan Provincial Education Department(24B0292)Water Resources Science and Technology Project of Hunan Province(XSKJ2023059-41)the Guangxi Key Research and Development Program(AB23075184)。
文摘Understanding the deterioration behaviors and mechanisms of rocks under thermo-hydromechanical(THM)interactions is crucial for mitigating slope instability.In this study,the physicomechanical properties of silty mudstone subjected to THM interactions were investigated by triaxial tests.The underlying micro-mechanisms were revealed using microscopic tests.The triaxial test results indicate that the strength parameters of silty mudstone decrease by 89.50%(deformation modulus),78.15%(peak strength),70.58%(cohesion),and 48.65%(friction angle)under 16 THM cycles,a load of 300 kPa,and alternating between 0℃water immersion and 60℃drying.The SEM test results indicate that the deterioration of silty mudstone strength primarily results from hydrothermal-expansion softening and cracking driven by the TLHM interactions.The specimens manifest shear failure under confining pressure exceeding 140 kPa.Furthermore,a new constitutive model considering hydrothermalexpansion strain and non-linear deformation characteristics was developed.The discrepancy between the experimentally measured peak strength and the damage constitutive model prediction remains below 5%.The proposed model is verified to be in satisfactory agreement with the experimental results.The self-designed THM apparatus overcomes the limitations of traditional investigations,enabling simultaneous consideration of thermal,hydraulic,and mechanical interactions.
