Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPFE)simulations,co-deformation and instability of hetero-phase interface in different material systems were herein...Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPFE)simulations,co-deformation and instability of hetero-phase interface in different material systems were herein studied for polycrystalline metal matrix composites(MMCs).Local stress and strain fields in two types of 3layer MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive deformations.Accordingly,more severe strain-induced interface instability can be observed in the fcc/bcc systems than in the fcc/fcc systems upon refining to metallic nanolayered composites(MNCs).By detailed analysis of stress and strain localization,it has been demonstrated that the interface instability is always accompanied by high-stress concentration,i.e.,thermodynamic characteristics,or high strain prevention i.e.,kinetic characteristics,at the hetero-phase interface.It then follows that the thermodynamic driving forceG and the kinetic energy barrier Q during dislocation and shear banding can be adopted to classify the deformation modes,following the so-called thermo-kinetic correlation.Then by inserting a high density of high-energy interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-phase interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,thus efficiently suppressing the shear band,stabilizing the hetero-phase interface,and obtaining an exceptional combination in strength and ductility.Such hetero-phase interface chosen by a couple of thermodynamics and kinetics can be defined as breaking the thermo-kinetic correlation and has been proposed for artificially designing MNCs.展开更多
Electrocatalytic nitrogen reduction reaction(NRR)is considered as an attractive approach for ammonia synthesis under mild conditions.A bottleneck of NRR is the exploration of efficient catalysts for accelerating react...Electrocatalytic nitrogen reduction reaction(NRR)is considered as an attractive approach for ammonia synthesis under mild conditions.A bottleneck of NRR is the exploration of efficient catalysts for accelerating reaction kinetics,among which heterogeneous structures possessing distinct atomic arrangement could modify electronic structure,and therefore altering their NRR activity.Here,we report a facile strategy for fabricating hetero-phase metal oxides derived from metal organic framework that are further integrated with Au nanoparticles as NRR catalysts.The phase composition of zirconia can be easily adjusted by simply changing the reaction temperature,where the monoclinic and tetragonal phases with the roughly close proportions have a distinct interface,leading to a strong interaction between Au and ZrO_(2).The enhanced interaction renders Au to be more electropositive and facilitates stronger binding to N_(2).As a result,a remarkable ammonia yield of 22.32μg h^(-1)mg_(cat.)^(-1) and a Faradaic efficiency of 31.92%can be achieved at low overpotential.This work is expected to pave the way for the design of heterogeneous structures and the exploration of hetero-phase nanostructures in boosting the electrocatalytic NRR.展开更多
The mechanism of liquid phase back-mixing in the liquid-solid fluidized bed has been studied.The radial parabolic distribution of liquid velocity is found to be the main motivation of particles’circulating movement w...The mechanism of liquid phase back-mixing in the liquid-solid fluidized bed has been studied.The radial parabolic distribution of liquid velocity is found to be the main motivation of particles’circulating movement which in trun causes the liquid back-mixing.The liquid back-mixing can be reduced by evening the radial distribution of liquid velocity.This is achieved by a hetero-pores distributor which has a resistant coefficient distribution analogous to that of liquid velocity.The experimental result shows that the hetero-pores distributor reduces the liquid back- mixing effectively.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance i...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance in TMDs based transistors seriously hinders their applications in complementary electronics.In this work,we show that an Ohmic homojunction n-type tungsten diselenide(WSe_(2))transistor is realized through spatially controlling cesium(Cs)doping region near the contacts.We find that the remarkable electron doping effect of Cs stimulates a semiconductor to metal(2H to 1T')phase transition in WSe_(2),and hence the formation of 2H-1T’hetero-phase contact.Our method significantly optimizes the WSe_(2) transport behavior with a perfect low subthreshold swing of-61 mV/dec and ultrahigh current on/off ratio exceeding-10^(9).Meanwhile,the electron mobility is enhanced by nearly 50 times.We elucidate that the ideal n-type behavior originates from the negligible Schottky barrier height of~19 meV and low contact resistance of-0.9Ωk·μm in the 2H-1T’homojunction device.Moreover,based on the Ohmic hetero-phase configuration,a WSe_(2) inverter is achieved with a high gain of~270 and low power consumption of-28 pW.Our findings envision Cs functionalization as an effective method to realize ideal Ohmic contact in 2D WSe_(2) transistors towards high performance complementary electronic devices.展开更多
基金support of the National Natural Science Foundation of China(No.52130110 and 51901182)the Research Fund of the State Key Laboratory of Solidification Process-ing(No.2022-TS-01).
文摘Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPFE)simulations,co-deformation and instability of hetero-phase interface in different material systems were herein studied for polycrystalline metal matrix composites(MMCs).Local stress and strain fields in two types of 3layer MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive deformations.Accordingly,more severe strain-induced interface instability can be observed in the fcc/bcc systems than in the fcc/fcc systems upon refining to metallic nanolayered composites(MNCs).By detailed analysis of stress and strain localization,it has been demonstrated that the interface instability is always accompanied by high-stress concentration,i.e.,thermodynamic characteristics,or high strain prevention i.e.,kinetic characteristics,at the hetero-phase interface.It then follows that the thermodynamic driving forceG and the kinetic energy barrier Q during dislocation and shear banding can be adopted to classify the deformation modes,following the so-called thermo-kinetic correlation.Then by inserting a high density of high-energy interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-phase interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,thus efficiently suppressing the shear band,stabilizing the hetero-phase interface,and obtaining an exceptional combination in strength and ductility.Such hetero-phase interface chosen by a couple of thermodynamics and kinetics can be defined as breaking the thermo-kinetic correlation and has been proposed for artificially designing MNCs.
基金supported by the National Natural Science Foundation(Nos.22075133 and 21701086)。
文摘Electrocatalytic nitrogen reduction reaction(NRR)is considered as an attractive approach for ammonia synthesis under mild conditions.A bottleneck of NRR is the exploration of efficient catalysts for accelerating reaction kinetics,among which heterogeneous structures possessing distinct atomic arrangement could modify electronic structure,and therefore altering their NRR activity.Here,we report a facile strategy for fabricating hetero-phase metal oxides derived from metal organic framework that are further integrated with Au nanoparticles as NRR catalysts.The phase composition of zirconia can be easily adjusted by simply changing the reaction temperature,where the monoclinic and tetragonal phases with the roughly close proportions have a distinct interface,leading to a strong interaction between Au and ZrO_(2).The enhanced interaction renders Au to be more electropositive and facilitates stronger binding to N_(2).As a result,a remarkable ammonia yield of 22.32μg h^(-1)mg_(cat.)^(-1) and a Faradaic efficiency of 31.92%can be achieved at low overpotential.This work is expected to pave the way for the design of heterogeneous structures and the exploration of hetero-phase nanostructures in boosting the electrocatalytic NRR.
文摘The mechanism of liquid phase back-mixing in the liquid-solid fluidized bed has been studied.The radial parabolic distribution of liquid velocity is found to be the main motivation of particles’circulating movement which in trun causes the liquid back-mixing.The liquid back-mixing can be reduced by evening the radial distribution of liquid velocity.This is achieved by a hetero-pores distributor which has a resistant coefficient distribution analogous to that of liquid velocity.The experimental result shows that the hetero-pores distributor reduces the liquid back- mixing effectively.
基金the financial support from the National Natural Science Foundation of China(Nos.U2032147,21872100 and 62004128)Singapore MOE Grants MOE-2019-T2-1-002+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB30000000)Fundamental Research Foundation of Shenzhen(Nos.JCYJ20170817100405375 and JCYJ20190808152607389).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have been rapidly established as promising building blocks for versatile atomic scale circuits and multifunctional devices.However,the high contact resistance in TMDs based transistors seriously hinders their applications in complementary electronics.In this work,we show that an Ohmic homojunction n-type tungsten diselenide(WSe_(2))transistor is realized through spatially controlling cesium(Cs)doping region near the contacts.We find that the remarkable electron doping effect of Cs stimulates a semiconductor to metal(2H to 1T')phase transition in WSe_(2),and hence the formation of 2H-1T’hetero-phase contact.Our method significantly optimizes the WSe_(2) transport behavior with a perfect low subthreshold swing of-61 mV/dec and ultrahigh current on/off ratio exceeding-10^(9).Meanwhile,the electron mobility is enhanced by nearly 50 times.We elucidate that the ideal n-type behavior originates from the negligible Schottky barrier height of~19 meV and low contact resistance of-0.9Ωk·μm in the 2H-1T’homojunction device.Moreover,based on the Ohmic hetero-phase configuration,a WSe_(2) inverter is achieved with a high gain of~270 and low power consumption of-28 pW.Our findings envision Cs functionalization as an effective method to realize ideal Ohmic contact in 2D WSe_(2) transistors towards high performance complementary electronic devices.
