Quasi-zero-stiffness(QZS)vibration isolators have been widely studied,because they show excellent high static and low dynamic stiffnesses and can effectively solve low-frequency and ultralow-frequency vibration.Howeve...Quasi-zero-stiffness(QZS)vibration isolators have been widely studied,because they show excellent high static and low dynamic stiffnesses and can effectively solve low-frequency and ultralow-frequency vibration.However,traditional QZS(T-QZS)vibration isolators usually adopt linear damping,owing to which achieving good isolation performance at both low and high frequencies is difficult.T-QZS isolators exhibit hardening stiffness characteristics,and their vibration isolation performance is even worse than that of linear vibration isolators under a large excitation amplitude.Therefore,this study proposes a QZS isolator with a shear-thinning viscous damper(SVD)to improve the vibration isolation performance of the T-QZS isolators.The force-velocity relation of the SVD is obtained,and a dynamic model is established for the isolator.The dynamic responses of the system are solved using the harmonic balance method(HBM)and the Runge-Kutta method.The vibration isolation performance of the system is evaluated using force transmissibility,and the isolator parameters are analyzed.The results show that compared with the T-QZS isolators,the proposed QZS-SVD isolator achieves the lower initial vibration isolation frequency and peak value,and exhibits better vibration isolation performance at medium and high frequencies.Moreover,the proposed isolator can withstand a large excitation amplitude in the effective vibration isolation range.展开更多
Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes...Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Sr_(n+1)IrnO_(3n+1)(n=1,2)is doped with carriers.While electron-doped Sr_(n+1)IrnO_(3n+1)(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr_(3)Ir_(2)O_(7)single crystals[Sr_3(Ir_(1-x)Fe_x)_(2)O_(7)]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr_(3)Ir_(2)O_(7)have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr_(3)Ir_(2)O_(7).Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr_(3)Ir_(2)O_(7),thereby offering a powerful strategy to modulate MIT in this material system.展开更多
The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as disti...The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as distinct electronic structures in both bulk and surface states of the material.An interesting next step is to manipulate the electronic states in this system.Here,we report angle-resolved photoemission spectroscopy(ARPES)evidence for a surface-induced orbitalselective band reconstruction in Cs V_(3)Sb_(5).A significant energy shift of the electron-like band aroundΓand a moderate energy shift of the hole-like band around M are observed as a function of time.This evolution is reproduced in a much shorter time scale by in-situ annealing of the Cs V_(3)Sb_(5) sample.Orbital-resolved density functional theory(DFT)calculations reveal that the momentum-dependent band reconstruction is associated with different orbitals for the bands aroundΓand M,and the time-dependent evolution points to the change of sample surface that is likely caused by the formation of Cs vacancies on the surface.Our results indicate the possibility of orbital-selective control of the band structure via surface modification,which may open a new avenue for manipulating exotic phenomena in this material system,including superconductivity.展开更多
Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism an...Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism and strong electronic correlations—two essential ingredients for unconventional superconductivity,are absent in this V-based Kagome metal.CsCr_(3)Sb_(5) is a newly discovered Cr-based parallel of CsV_(3)Sb_(5),in which magnetism appears with charge density wave and superconductivity at different temperature and pressure regions.Enhanced electronic correlations are also suggested by theoretical proposals due to the calculated flat bands.Here,we report angle-resolved photoemission measurements and firstprinciples calculations on this new material system.Electron energy bands and the associated orbitals are resolved.Flat bands are observed near the Fermi level.Doping dependent measurements on Cs(V_(1-x)Cr_(x))_(3)Sb_(5) reveal a gradually enhanced band renormalization from CsV_(3)Sb_(5) to CsCr_(3)Sb_(5),accompanied by distinct spatial symmetry breaking states in the phase diagram.展开更多
The superconducting ground state of kagome metals AV_(3)Sb_(5)(where A stands for K,Rb,or Cs)emerges from an exotic charge density wave(CDW)state that potentially breaks both rotational and time reversal symmetries.Ho...The superconducting ground state of kagome metals AV_(3)Sb_(5)(where A stands for K,Rb,or Cs)emerges from an exotic charge density wave(CDW)state that potentially breaks both rotational and time reversal symmetries.However,the specifics of the Cooper pairing mechanism,and the nature of the interplay between these two states remain elusive,largely due to the lack of momentum-space(k-space)superconducting energy gap structure.By implementing Bogoliubov quasiparticle interference(B QPI)imaging,we obtain k-space information on the multiband superconducting gap structureΔ_(SC)^(i)(k)in pristine CsV_(3)Sb_(5).We show that the estimated energy gap on the vanadium d_(xy/x^(2)-y^(2))orbital is anisotropic but nodeless,with a minimal value located near the M point.Interestingly,a comparison ofΔ_(SC)^(i)(k)with the CDW gapΔ_(CDW)^(i)(k)obtained by angle-re solved photoemission spectro scopy(ARPES)reveals direct k-space competition between the se two order parameters,i.e.,the opening of a large(small)CDW gap at a given momentum corresponds to a small(large)superconducting gap.When the long-range CDW order is suppressed by replacing vanadium with titanium,we find a nearly isotropic energy gap on both the V and Sb bands.This information will be critical for identifying the microscopic pairing mechanism and its interplay with intertwined electro nic orders in this kagome superconductor family.展开更多
Short-chain dehydrogenases/reductases(SDRs)are ubiquitously distributed across diverse organisms and play pivotal roles in the growth,as well as endogenous and exogenous metabolism of various substances,including drug...Short-chain dehydrogenases/reductases(SDRs)are ubiquitously distributed across diverse organisms and play pivotal roles in the growth,as well as endogenous and exogenous metabolism of various substances,including drugs.The expression levels of SDR genes are reportedly upregulated in the fenpropathrin(FEN)-resistant(FeR)strain of Tetranychus cinnabarinus.However,the functions of these SDR genes in acaricide tolerance remain elusive.In this study,the activity of SDRs was found to be significantly higher(2.26-fold)in the FeR strain compared to the susceptible strain(SS)of T.cinnabarinus.A specific upregulated SDR gene,named SDR112C1,exhibited significant overexpression(3.13-fold)in the FeR population compared with that in the SS population.Furthermore,the expression of SDR112C1 showed a significant increase in the response to FEN induction.Additionally,knockdown of the SDR112C1 gene resulted in decreased SDR activity and reduced mite viability against FEN.Importantly,heterologous expression and in vitro incubation assays confirmed that recombinant SDR112C1 could effectively deplete FEN.Moreover,the overexpression of the SDR112C1 gene in Drosophila melanogaster significantly decreased the toxicity of FEN to transgenic fruit flies.These findings suggest that the overexpression of SDR SDR112C1 is a crucial factor contributing to FEN tolerance in T.cinnabarinus.This discovery not only enhances our understanding of SDR-mediated acaricide tolerance but also introduces a new family of detoxification enzymes to consider in practice,beyond cytochrome P450s,carboxyl/choline esterases and glutathione S-transferases.展开更多
The realm of high-end equipment necessitates the development of plate-type metastructures integrating lightweight,high static load-bearing,and superior low-frequency dynamic performance.However,the rapid on-demand inv...The realm of high-end equipment necessitates the development of plate-type metastructures integrating lightweight,high static load-bearing,and superior low-frequency dynamic performance.However,the rapid on-demand inverse design of such platetype metastructures remains challenging.This study proposes a “data + non-data” hybrid-driven inverse design(HDID) method for a class of locally resonant plate-type multifunctional metastructure(LRPMM).The LRPMM primarily comprises two spiral plates,a square honeycomb core,and a cylinder.Its load-bearing and dynamic performance are characterized by bending stiffness and flexural wave bandgap,respectively,both investigated through theoretical and numerical methods.The bandgap is predicted through the synthesis of a discrete dimensionality-reduction strategy and the plane-wave expansion method.Based on this,a dataset is generated,and a forward prediction network model is trained.Then,a “data + non-data” model is constructed to target the customization of bending stiffness and flexural wave bandgap.The core of the hybrid-driven tandem neural network model lies in the fact that pre-trained forward prediction network models are employed for predicting the flexural wave bandgap with a strongly nonlinear property,while physical equations are used to characterize the bending stiffness with a weakly nonlinear property.Results demonstrate that the proposed HDID method can improve the design efficiency by over 10% while ensuring high accuracy,compared with the conventional data-driven inverse design(DDID) method.Notably,the proposed method enables the design of the metastructure with a bending stiffness of 18315 N m,an equivalent density of 2 g cm ^(-3),and effective flexural wave suppression in the frequency range of 55.9-94.5 Hz.Finally,vibration suppression experiments are conducted to validate the effectiveness of the proposed HDID method.展开更多
Correlation-driven superconductivity has been predicted in the kagome lattice for a long time.The recent discovery of superconductivity and charge density wave(CDW)in the new kagome familyAV_(3)Sb_(5)(A=K,Rb,Cs)[1]has...Correlation-driven superconductivity has been predicted in the kagome lattice for a long time.The recent discovery of superconductivity and charge density wave(CDW)in the new kagome familyAV_(3)Sb_(5)(A=K,Rb,Cs)[1]has generated a hot debate on whether this family is a real platform to host exotic superconducting pairing(such as d+id or f-wave)as predicted by the Kagome-Hubbard model[2-4].Experimentally,the results from different techniques seem to be very contradictory at the beginning[5,6].展开更多
基金Project supported by the Key Program of National Natural Science Foundation of China(No.11832009)the National Natural Science Foundation of China(Nos.11902085 and 12172095)the Natural Science Foundation of Guangdong Province of China(No.2021A1515010320)
文摘Quasi-zero-stiffness(QZS)vibration isolators have been widely studied,because they show excellent high static and low dynamic stiffnesses and can effectively solve low-frequency and ultralow-frequency vibration.However,traditional QZS(T-QZS)vibration isolators usually adopt linear damping,owing to which achieving good isolation performance at both low and high frequencies is difficult.T-QZS isolators exhibit hardening stiffness characteristics,and their vibration isolation performance is even worse than that of linear vibration isolators under a large excitation amplitude.Therefore,this study proposes a QZS isolator with a shear-thinning viscous damper(SVD)to improve the vibration isolation performance of the T-QZS isolators.The force-velocity relation of the SVD is obtained,and a dynamic model is established for the isolator.The dynamic responses of the system are solved using the harmonic balance method(HBM)and the Runge-Kutta method.The vibration isolation performance of the system is evaluated using force transmissibility,and the isolator parameters are analyzed.The results show that compared with the T-QZS isolators,the proposed QZS-SVD isolator achieves the lower initial vibration isolation frequency and peak value,and exhibits better vibration isolation performance at medium and high frequencies.Moreover,the proposed isolator can withstand a large excitation amplitude in the effective vibration isolation range.
基金supported by the National Natural Science Foundation of China(Grant No.12074358)the National Key Research and Development Program of China(Grant No.2024YFA1408103)+2 种基金the International Partnership Program of the Chinese Academy of Sciences(Grant No.123GJHZ2022035MI)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000015)。
文摘Metal-insulator transition(MIT)in perovskite iridium oxides Sr_(n+1)IrnO_(3n+1)represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin-orbit coupling(SOC).MIT takes place when Sr_(n+1)IrnO_(3n+1)(n=1,2)is doped with carriers.While electron-doped Sr_(n+1)IrnO_(3n+1)(n=1,2)systems have been extensively investigated,hole-doped samples are still limited.Here,we report the first growth of Fe-doped(hole-doped)Sr_(3)Ir_(2)O_(7)single crystals[Sr_3(Ir_(1-x)Fe_x)_(2)O_(7)]with the doping level 0.1≤x≤0.28.An MIT behavior is observed at the doping level of x~0.16 from resistivity measurements.Electronic structures of Fe-doped Sr_(3)Ir_(2)O_(7)have been revealed by angle-resolved photoemission spectroscopy(ARPES)measurements.The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr_(3)Ir_(2)O_(7).Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr_(3)Ir_(2)O_(7),thereby offering a powerful strategy to modulate MIT in this material system.
基金supported by the National Natural Science Foundation of China(Grant Nos.11832009,12172095,and 11902085)the Natural Science Foundation of Guangdong Province(Grant No.2021A1515010320)We are also very grateful to the anonymous reviewers for their contributions.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.WK3510000008 and WK3510000012)USTC start-up fund+3 种基金supported by the UC Santa Barbara NSF Quantum Foundry funded via the Q-AMASE-i program under award DMR-1906325the NSF Materials Research Science and Engineering Center at UC Santa Barbara(DMR-1720256)support from the California Nano Systems Institute through the Elings Fellowship programsupported by the National Science Foundation Graduate Research Fellowship Program under Grant No.DGE1650114。
文摘The two-dimensional(2 D)kagome superconductor Cs V_(3)Sb_(5) has attracted much recent attention due to the coexistence of superconductivity,charge orders,topology and kagome physics,which manifest themselves as distinct electronic structures in both bulk and surface states of the material.An interesting next step is to manipulate the electronic states in this system.Here,we report angle-resolved photoemission spectroscopy(ARPES)evidence for a surface-induced orbitalselective band reconstruction in Cs V_(3)Sb_(5).A significant energy shift of the electron-like band aroundΓand a moderate energy shift of the hole-like band around M are observed as a function of time.This evolution is reproduced in a much shorter time scale by in-situ annealing of the Cs V_(3)Sb_(5) sample.Orbital-resolved density functional theory(DFT)calculations reveal that the momentum-dependent band reconstruction is associated with different orbitals for the bands aroundΓand M,and the time-dependent evolution points to the change of sample surface that is likely caused by the formation of Cs vacancies on the surface.Our results indicate the possibility of orbital-selective control of the band structure via surface modification,which may open a new avenue for manipulating exotic phenomena in this material system,including superconductivity.
基金the support by the National Natural Science Foundation of China(Grant Nos.52273309,and 52261135638)the Fundamental Research Funds for the Central Universities(Grant No.WK3510000015)+10 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the International Partnership Program of the Chinese Academy of Sciences(Grant No.123GJHZ2022035MI)the support by the National Key R&D Program of China(Grant No.2023YFA1406304)the National Natural Science Foundation of China(Grant No.U2032208)the support by the National Natural Science Foundation of China(Grant Nos.12474158,12234017,and 12488101)the National Key R&D Program of China(Grant No.2024YFA1408103)Anhui Initiative in Quantum Information Technologies(Grant No.AHY170000)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302800)Beijing Institute of Technology was supported by the National Key R&D Program of China(Grant Nos.2020YFA0308800,and 2022YFA1403400)the National Natural Science Foundation of China(Grant No.92065109)the Beijing Natural Science Foundation(Grant Nos.Z210006,Z190006)。
文摘Kagome metal CsV3Sb5 has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors.Nevertheless,magnetism and strong electronic correlations—two essential ingredients for unconventional superconductivity,are absent in this V-based Kagome metal.CsCr_(3)Sb_(5) is a newly discovered Cr-based parallel of CsV_(3)Sb_(5),in which magnetism appears with charge density wave and superconductivity at different temperature and pressure regions.Enhanced electronic correlations are also suggested by theoretical proposals due to the calculated flat bands.Here,we report angle-resolved photoemission measurements and firstprinciples calculations on this new material system.Electron energy bands and the associated orbitals are resolved.Flat bands are observed near the Fermi level.Doping dependent measurements on Cs(V_(1-x)Cr_(x))_(3)Sb_(5) reveal a gradually enhanced band renormalization from CsV_(3)Sb_(5) to CsCr_(3)Sb_(5),accompanied by distinct spatial symmetry breaking states in the phase diagram.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1602600,and 2018YFA0305602)the National Natural Science Foundation of China(Grant Nos.11888101,12074364,52273309,and 52261135638)+5 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB25000000)the Anhui Initiative in Quantum Information Technologies(Grant No.AHY160000)the Fundamental Research Funds for the Central Universities(Grant Nos.WK3510000012,and WK3510000015)the Major Basic Program of the Natural Science Foundation of Shandong Province(Grant No.ZR2021ZD01)。
文摘The superconducting ground state of kagome metals AV_(3)Sb_(5)(where A stands for K,Rb,or Cs)emerges from an exotic charge density wave(CDW)state that potentially breaks both rotational and time reversal symmetries.However,the specifics of the Cooper pairing mechanism,and the nature of the interplay between these two states remain elusive,largely due to the lack of momentum-space(k-space)superconducting energy gap structure.By implementing Bogoliubov quasiparticle interference(B QPI)imaging,we obtain k-space information on the multiband superconducting gap structureΔ_(SC)^(i)(k)in pristine CsV_(3)Sb_(5).We show that the estimated energy gap on the vanadium d_(xy/x^(2)-y^(2))orbital is anisotropic but nodeless,with a minimal value located near the M point.Interestingly,a comparison ofΔ_(SC)^(i)(k)with the CDW gapΔ_(CDW)^(i)(k)obtained by angle-re solved photoemission spectro scopy(ARPES)reveals direct k-space competition between the se two order parameters,i.e.,the opening of a large(small)CDW gap at a given momentum corresponds to a small(large)superconducting gap.When the long-range CDW order is suppressed by replacing vanadium with titanium,we find a nearly isotropic energy gap on both the V and Sb bands.This information will be critical for identifying the microscopic pairing mechanism and its interplay with intertwined electro nic orders in this kagome superconductor family.
基金funded by the National Natural Science Foundation of China(U2202202)the National Key Research,Development Program of China(2023YFD1400000)Chongqing China Three Gorges Museum independent project(3GM2022-KTZ06).
文摘Short-chain dehydrogenases/reductases(SDRs)are ubiquitously distributed across diverse organisms and play pivotal roles in the growth,as well as endogenous and exogenous metabolism of various substances,including drugs.The expression levels of SDR genes are reportedly upregulated in the fenpropathrin(FEN)-resistant(FeR)strain of Tetranychus cinnabarinus.However,the functions of these SDR genes in acaricide tolerance remain elusive.In this study,the activity of SDRs was found to be significantly higher(2.26-fold)in the FeR strain compared to the susceptible strain(SS)of T.cinnabarinus.A specific upregulated SDR gene,named SDR112C1,exhibited significant overexpression(3.13-fold)in the FeR population compared with that in the SS population.Furthermore,the expression of SDR112C1 showed a significant increase in the response to FEN induction.Additionally,knockdown of the SDR112C1 gene resulted in decreased SDR activity and reduced mite viability against FEN.Importantly,heterologous expression and in vitro incubation assays confirmed that recombinant SDR112C1 could effectively deplete FEN.Moreover,the overexpression of the SDR112C1 gene in Drosophila melanogaster significantly decreased the toxicity of FEN to transgenic fruit flies.These findings suggest that the overexpression of SDR SDR112C1 is a crucial factor contributing to FEN tolerance in T.cinnabarinus.This discovery not only enhances our understanding of SDR-mediated acaricide tolerance but also introduces a new family of detoxification enzymes to consider in practice,beyond cytochrome P450s,carboxyl/choline esterases and glutathione S-transferases.
基金supported by the Hebei Natural Science Foundation (Grant No.A2024203026)the National Natural Science Foundation of China (Grant No.12572030)。
文摘The realm of high-end equipment necessitates the development of plate-type metastructures integrating lightweight,high static load-bearing,and superior low-frequency dynamic performance.However,the rapid on-demand inverse design of such platetype metastructures remains challenging.This study proposes a “data + non-data” hybrid-driven inverse design(HDID) method for a class of locally resonant plate-type multifunctional metastructure(LRPMM).The LRPMM primarily comprises two spiral plates,a square honeycomb core,and a cylinder.Its load-bearing and dynamic performance are characterized by bending stiffness and flexural wave bandgap,respectively,both investigated through theoretical and numerical methods.The bandgap is predicted through the synthesis of a discrete dimensionality-reduction strategy and the plane-wave expansion method.Based on this,a dataset is generated,and a forward prediction network model is trained.Then,a “data + non-data” model is constructed to target the customization of bending stiffness and flexural wave bandgap.The core of the hybrid-driven tandem neural network model lies in the fact that pre-trained forward prediction network models are employed for predicting the flexural wave bandgap with a strongly nonlinear property,while physical equations are used to characterize the bending stiffness with a weakly nonlinear property.Results demonstrate that the proposed HDID method can improve the design efficiency by over 10% while ensuring high accuracy,compared with the conventional data-driven inverse design(DDID) method.Notably,the proposed method enables the design of the metastructure with a bending stiffness of 18315 N m,an equivalent density of 2 g cm ^(-3),and effective flexural wave suppression in the frequency range of 55.9-94.5 Hz.Finally,vibration suppression experiments are conducted to validate the effectiveness of the proposed HDID method.
基金supported by the National Natural Science Foundation of China(11888101)the National Key R&D Program of China(2017YFA0303000)+1 种基金the Anhui Initiative in Quantum Information Technologies(AHY160000)the Innovation Program for Quantum Science and Technology(2021ZD0302802)。
文摘Correlation-driven superconductivity has been predicted in the kagome lattice for a long time.The recent discovery of superconductivity and charge density wave(CDW)in the new kagome familyAV_(3)Sb_(5)(A=K,Rb,Cs)[1]has generated a hot debate on whether this family is a real platform to host exotic superconducting pairing(such as d+id or f-wave)as predicted by the Kagome-Hubbard model[2-4].Experimentally,the results from different techniques seem to be very contradictory at the beginning[5,6].
