In this paper, a new physically based constitutive model is developed for hexagonal close-packed metals, especially the Ti-6Al-4V alloy, subjected to high strain rate and different temperatures based on the microscopi...In this paper, a new physically based constitutive model is developed for hexagonal close-packed metals, especially the Ti-6Al-4V alloy, subjected to high strain rate and different temperatures based on the microscopic mechanism of plastic deformation and the theory of thermally activated dislocation motion. A global analysis of constitutive parameters based on the Latin Hypercube Sampling method and the Spearman＇s rank correlation method is adopted in order to improve the identification efficiency of parameters. Then, an optimal solution of constitutive parameters as a whole is obtained by using a global genetic algorithm composed of an improved niche genetic algorithm, a global peak determination strategy and the local accurate search techniques. It is concluded that the proposed constitutive modal can accurately describe the Ti-6Al-4V alloy＇s dynamic behavior because the prediction results of the model are in good agreement with the experimental data.展开更多
Using a double templating method by electroless deposition within a templating organic porous mold,we fabricate a monolayer of hexagonal-close-packed metallic nanoshells,each with a small opening.Light transmission sp...Using a double templating method by electroless deposition within a templating organic porous mold,we fabricate a monolayer of hexagonal-close-packed metallic nanoshells,each with a small opening.Light transmission spectra of the metallic nanoshell arrays are measured,which show transmission resonances at specific wavelengths whose positions are observed to be independent of the incident angle as well as light polarizations.More interestingly,the resonance wavelengths of Mie plasmon modes are also independent of the surrounding medium.Further numerical simulations confirm these transmission resonances and reveal that they are attributed to the excitations of highly localized dipolar,quadrupolar and hexapolar Mie plasmon modes,which are highly confined within metallic nanoshells.展开更多
Employing ab initio calculations, we systematically investigated tile energy paths of [1012] twin-related lattice reorientation in hexagonal metals Be, Mg, Sc, Ti, Co, Y, Zr, Tc, Ru, Gd, Tb, Dy, Ho, Er, Tin, Lu, Hf, R...Employing ab initio calculations, we systematically investigated tile energy paths of [1012] twin-related lattice reorientation in hexagonal metals Be, Mg, Sc, Ti, Co, Y, Zr, Tc, Ru, Gd, Tb, Dy, Ho, Er, Tin, Lu, Hf, Re, and Os. Among the studied systems, lattice reorientation energy increases in the order of Mg, Gd, Tb, Dy, Zr, Tc, Ti, Ho, Y, Co, Er, Sc, Be, Tin, Lu, Hf, Re, Ru and Os. The reorientation process consists of shear and shuffle components. Concerning the significance of shuffle, these hexagonal metals fall into two groups. In the first group, which includes Mg, Co, Ru, Re and Os, regardless of the shear amount, subsequent shuffle is an energy-uphill process, while in the second group, which includes Ti, Tc, Be, Y. Gd, Tb, Dy, Ho, Zr, Er, Sc, Hf, Lu and Tin, shuffle becomes an energy-downhill process if shear component reaches an adequate level （at least 60%）. These results qualitatively explain the present observation of lattice reorientation in hexagonal metals, and shed light upon a general understanding on the [1012] twinning behavior in the aim of improving materials properties.展开更多
The addition of hexagonal-close-packed(hcp)non-rare-earth elements Zr,Ti and Co,to the 10-component hep rare-earth-based high-entropy alloys(HEAs)with a composition of ScYLaNdGdTbDyHoErLuX(X=Zr,Co and Ti)was investiga...The addition of hexagonal-close-packed(hcp)non-rare-earth elements Zr,Ti and Co,to the 10-component hep rare-earth-based high-entropy alloys(HEAs)with a composition of ScYLaNdGdTbDyHoErLuX(X=Zr,Co and Ti)was investigated.The enthalpy of mixing between elements was found to have a significant effect on the formation of phases.The addition of Co combines with elements that had a strong chemical affinity to form intermetallic compounds by the effect of enthalpy.Ti was added with all elements with poor chemical affinity and exhibited rejection to form a phase alone.These were the two terminal manifestations of the role of enthalpy over entropy.Part of Zr was soluble in the matrix under the action of entropy,while the other part had a greater affinity for Sc than the other elements to form a precipitate under the action of enthalpy.This was the result of the local balance between the effect of enthalpy and entropy.The solid solution of the elements had different degrees of strengthening effect,among which Zr had the most excellent strengthening effect from 185 to 355 MPa,so the solid solution strengthening model and precipitation strengthening model were proposed to predict the strength of the alloy with the addition of Zr effectively.展开更多
Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigu...Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,etc.Among all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely reported.Up to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional elements.Their phase transformation and magnetic properties have also aroused wide concern.This study summarizes the above results and provides the forecast to the future.展开更多
Metallic hydrogen could be not only high-efficiency fuel for nuclear fusion and high explosive but also a high-temperature superconductor. The study of metallic hydrogen is of great help to solving some important prob...Metallic hydrogen could be not only high-efficiency fuel for nuclear fusion and high explosive but also a high-temperature superconductor. The study of metallic hydrogen is of great help to solving some important problems in the field of geophysics and astrophysics, such as the electronic and magnetic properties of the giant planets (Jupiter and Saturn) and their evolution, processes. So the study of metallic hydrogen is of momentous significance both theoretically and practically. In 1935 Wigner and Huntington pro-展开更多
Hexagonal boron nitride(h-BN)exhibits unique physicochemical properties,and the interfaces it forms with metals are crucial for the development of next-generation electronic devices,catalysts,and high-performance comp...Hexagonal boron nitride(h-BN)exhibits unique physicochemical properties,and the interfaces it forms with metals are crucial for the development of next-generation electronic devices,catalysts,and high-performance composite materials.This review focuses on interface engineering within h-BN/metal systems,systematically analyzing the interfacial characteristics associated with two primary approaches:in situ growth and ex situ compositing.Specifically,during the in situ growth of h-BN thin films on metal substrates,the metal substrate and growth conditions exert multifaceted influences on film quality through interfacial coupling.For ex situ preparation of h-BN/metal composites,interface construction is synergistically determined by h-BN dimension,matrix properties,and the fabrication process.This review aims to elucidate the fundamental principles and unique mechanisms of h-BN/metal interface control,thereby providing strategic insights for the designing and optimizing advanced h-BN-based functional devices and composite materials.展开更多
Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transpar...Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transparent,flexible,and mechanically robust neural electrodes with high electrochemical performance remains challenging.In this study,we fabricated transparent(72.7%at 570 nm),mechanically robust(0.05%resistance change after 50k bending cycles)ultrathin Au microelectrodes for micro-electrocorticography(µECoG)using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer.These transparentµECoG arrays,fabricated with biocompatible gold,exhibit excellent electrochemical properties(0.73Ω·cm^(2))for neural recording and stimulation with long-term stability.We recorded brain surface waves in vivo,maintaining a low baseline noise and a high signalto-noise ratio during acute and two-week recordings.In addition,we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm^(2)laser power density.This approach shows great potential for scalable,implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.展开更多
With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Wang QiangBin(王强斌)at the CAS Key Laboratory of Nano-Bio Interface,Division of N...With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Wang QiangBin(王强斌)at the CAS Key Laboratory of Nano-Bio Interface,Division of Nanobiomedicine and i-Lab,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,revealed the role of metal alloy crystal structure in oxygen evolution reaction,which was recently published in Angew Chem Int Ed(2019,58(18):6099—6103).展开更多
We have investigated twin boundaries in double-lattice hexagonal close-packed metallic materials,focusing on their atomic geometry.Combining accurate ab-initio methods and large-scale atomistic simulations we address ...We have investigated twin boundaries in double-lattice hexagonal close-packed metallic materials,focusing on their atomic geometry.Combining accurate ab-initio methods and large-scale atomistic simulations we address the following two fundamental questions:(i)What are the possible intrinsic twin boundary structures in hcp crystals?(ii)Are these structures stable against small distortions?In order to help end a decade-long controversy over the experimental observations of the atomic structures of twin boundaries,we have determined the energetics,spectra,and transition mechanisms of the twin boundaries.Our results confirm that the mechanical stability controls structures which are observed.展开更多
As a very promising epitaxy technology,the remote epitaxy has attracted extensive attention in recent years,in which graphene is the most used interlayer material.As an isomorphic of graphene,two-dimensional(2D)hexago...As a very promising epitaxy technology,the remote epitaxy has attracted extensive attention in recent years,in which graphene is the most used interlayer material.As an isomorphic of graphene,two-dimensional(2D)hexagonal boron nitride(h-BN),is another promising interlayer for the remote epitaxy.However,there is a current debate on the feasibility of using h-BN as interlayer in the remote epitaxy.Herein,we demonstrate that the potential field of sapphire can completely penetrate monolayer h-BN,and hence the remote epitaxy of ZrS_(2) layers can be realized on sapphire substrates through monolayer h-BN.The field of sapphire can only partially penetrate the bilayer h-BN and result in the mixing of remote epitaxy and van der Waals(vdWs)epitaxy.Due to the weak interfacial scattering and high crystalline quality of ZrS_(2) epilayer,the ZrS_(2) photodetector with monolayer h-BN shows the best performance,with an on/off ratio of more than 2×10^(5) and a responsivity up to 379 mA·W^(-1).This work provides an efficient approach to prepare single-crystal transition metal dichalcogenides and their heterojunctions with h-BN,which have great potential in developing large-area 2D electronic devices.展开更多
基金the financial support by the National Natural Science Foundation of China Academy of Engineering Physicsthe jointly set-up"NSAF"joint fund under Contract No.U1430119
文摘In this paper, a new physically based constitutive model is developed for hexagonal close-packed metals, especially the Ti-6Al-4V alloy, subjected to high strain rate and different temperatures based on the microscopic mechanism of plastic deformation and the theory of thermally activated dislocation motion. A global analysis of constitutive parameters based on the Latin Hypercube Sampling method and the Spearman＇s rank correlation method is adopted in order to improve the identification efficiency of parameters. Then, an optimal solution of constitutive parameters as a whole is obtained by using a global genetic algorithm composed of an improved niche genetic algorithm, a global peak determination strategy and the local accurate search techniques. It is concluded that the proposed constitutive modal can accurately describe the Ti-6Al-4V alloy＇s dynamic behavior because the prediction results of the model are in good agreement with the experimental data.
基金Supported by the National Basic Research Program of China(No 2012CB921501)the National Natural Science Foundation of China(Nos 11174137,11104136,11021403,11004146)+1 种基金the Fundamental Research Funds for the Central Universities(No 1115020403)the Priority Academic Program Development(PAPD).
文摘Using a double templating method by electroless deposition within a templating organic porous mold,we fabricate a monolayer of hexagonal-close-packed metallic nanoshells,each with a small opening.Light transmission spectra of the metallic nanoshell arrays are measured,which show transmission resonances at specific wavelengths whose positions are observed to be independent of the incident angle as well as light polarizations.More interestingly,the resonance wavelengths of Mie plasmon modes are also independent of the surrounding medium.Further numerical simulations confirm these transmission resonances and reveal that they are attributed to the excitations of highly localized dipolar,quadrupolar and hexapolar Mie plasmon modes,which are highly confined within metallic nanoshells.
基金supported financially by the National Key Research and Development Program of China(No.2016YFB0701304)the National Natural Science Foundation of China(No.51671195)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2015151)
文摘Employing ab initio calculations, we systematically investigated tile energy paths of [1012] twin-related lattice reorientation in hexagonal metals Be, Mg, Sc, Ti, Co, Y, Zr, Tc, Ru, Gd, Tb, Dy, Ho, Er, Tin, Lu, Hf, Re, and Os. Among the studied systems, lattice reorientation energy increases in the order of Mg, Gd, Tb, Dy, Zr, Tc, Ti, Ho, Y, Co, Er, Sc, Be, Tin, Lu, Hf, Re, Ru and Os. The reorientation process consists of shear and shuffle components. Concerning the significance of shuffle, these hexagonal metals fall into two groups. In the first group, which includes Mg, Co, Ru, Re and Os, regardless of the shear amount, subsequent shuffle is an energy-uphill process, while in the second group, which includes Ti, Tc, Be, Y. Gd, Tb, Dy, Ho, Zr, Er, Sc, Hf, Lu and Tin, shuffle becomes an energy-downhill process if shear component reaches an adequate level （at least 60%）. These results qualitatively explain the present observation of lattice reorientation in hexagonal metals, and shed light upon a general understanding on the [1012] twinning behavior in the aim of improving materials properties.
基金financially supported by the Natural Science Foundation of Shanxi Province,China (Nos. 201901D111105 and 201901D111114)the Key Research and Development Program of Shanxi Province (No.202102050201008)+1 种基金the National Science Foundation,United States (Nos.DMR-1611180 and 1809640)the U.S.Army Research Office (Nos.W911NF-131-0438 and W911NF-19-2-0049)
文摘The addition of hexagonal-close-packed(hcp)non-rare-earth elements Zr,Ti and Co,to the 10-component hep rare-earth-based high-entropy alloys(HEAs)with a composition of ScYLaNdGdTbDyHoErLuX(X=Zr,Co and Ti)was investigated.The enthalpy of mixing between elements was found to have a significant effect on the formation of phases.The addition of Co combines with elements that had a strong chemical affinity to form intermetallic compounds by the effect of enthalpy.Ti was added with all elements with poor chemical affinity and exhibited rejection to form a phase alone.These were the two terminal manifestations of the role of enthalpy over entropy.Part of Zr was soluble in the matrix under the action of entropy,while the other part had a greater affinity for Sc than the other elements to form a precipitate under the action of enthalpy.This was the result of the local balance between the effect of enthalpy and entropy.The solid solution of the elements had different degrees of strengthening effect,among which Zr had the most excellent strengthening effect from 185 to 355 MPa,so the solid solution strengthening model and precipitation strengthening model were proposed to predict the strength of the alloy with the addition of Zr effectively.
基金financial support from the National Natural Science Foundation of China (No 51671020)Fundamental Research Funds for the Central Universities (No. FRF-MP-19-013)。
文摘Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,etc.Among all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely reported.Up to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional elements.Their phase transformation and magnetic properties have also aroused wide concern.This study summarizes the above results and provides the forecast to the future.
文摘Metallic hydrogen could be not only high-efficiency fuel for nuclear fusion and high explosive but also a high-temperature superconductor. The study of metallic hydrogen is of great help to solving some important problems in the field of geophysics and astrophysics, such as the electronic and magnetic properties of the giant planets (Jupiter and Saturn) and their evolution, processes. So the study of metallic hydrogen is of momentous significance both theoretically and practically. In 1935 Wigner and Huntington pro-
基金supported by the National Key R&D Program of China(2024YFA1209800)the National Natural Science Foundation of China(52371013)the Natural Science Foundation of Tianjin City(22JCZDJC00020).
文摘Hexagonal boron nitride(h-BN)exhibits unique physicochemical properties,and the interfaces it forms with metals are crucial for the development of next-generation electronic devices,catalysts,and high-performance composite materials.This review focuses on interface engineering within h-BN/metal systems,systematically analyzing the interfacial characteristics associated with two primary approaches:in situ growth and ex situ compositing.Specifically,during the in situ growth of h-BN thin films on metal substrates,the metal substrate and growth conditions exert multifaceted influences on film quality through interfacial coupling.For ex situ preparation of h-BN/metal composites,interface construction is synergistically determined by h-BN dimension,matrix properties,and the fabrication process.This review aims to elucidate the fundamental principles and unique mechanisms of h-BN/metal interface control,thereby providing strategic insights for the designing and optimizing advanced h-BN-based functional devices and composite materials.
基金supported in part by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2022-NR069917,RS-2024-00416319)in part by the‘DGIST intramural grant’(25-IRJoint-03)+1 种基金in part by an Ideas Grant from the National Health and Medical Research Council(NHMRC)of Australia(APP1188414)in part by the Interdisciplinary Research Initiatives Program from College of Engineering and College of Medicine,Seoul National University(grant no.800-20240490).
文摘Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging,and high-temporal-resolution electrical recording and stimulation.However,fabricating transparent,flexible,and mechanically robust neural electrodes with high electrochemical performance remains challenging.In this study,we fabricated transparent(72.7%at 570 nm),mechanically robust(0.05%resistance change after 50k bending cycles)ultrathin Au microelectrodes for micro-electrocorticography(µECoG)using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer.These transparentµECoG arrays,fabricated with biocompatible gold,exhibit excellent electrochemical properties(0.73Ω·cm^(2))for neural recording and stimulation with long-term stability.We recorded brain surface waves in vivo,maintaining a low baseline noise and a high signalto-noise ratio during acute and two-week recordings.In addition,we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm^(2)laser power density.This approach shows great potential for scalable,implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.
文摘With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Wang QiangBin(王强斌)at the CAS Key Laboratory of Nano-Bio Interface,Division of Nanobiomedicine and i-Lab,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,revealed the role of metal alloy crystal structure in oxygen evolution reaction,which was recently published in Angew Chem Int Ed(2019,58(18):6099—6103).
基金the financial supports of the Max-Planck Society at the Max-Planck-Institut fur Eisenforschung GmbH.the support from the Academy of Sciences of the Czech Republic through the Fellowship of J.E.Purkyne.
文摘We have investigated twin boundaries in double-lattice hexagonal close-packed metallic materials,focusing on their atomic geometry.Combining accurate ab-initio methods and large-scale atomistic simulations we address the following two fundamental questions:(i)What are the possible intrinsic twin boundary structures in hcp crystals?(ii)Are these structures stable against small distortions?In order to help end a decade-long controversy over the experimental observations of the atomic structures of twin boundaries,we have determined the energetics,spectra,and transition mechanisms of the twin boundaries.Our results confirm that the mechanical stability controls structures which are observed.
基金supported by the National Natural Science Foundation of China(Nos.62274151 and 61874106)the Natural Science Foundation of Beijing Municipality(No.4212045)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB43000000).
文摘As a very promising epitaxy technology,the remote epitaxy has attracted extensive attention in recent years,in which graphene is the most used interlayer material.As an isomorphic of graphene,two-dimensional(2D)hexagonal boron nitride(h-BN),is another promising interlayer for the remote epitaxy.However,there is a current debate on the feasibility of using h-BN as interlayer in the remote epitaxy.Herein,we demonstrate that the potential field of sapphire can completely penetrate monolayer h-BN,and hence the remote epitaxy of ZrS_(2) layers can be realized on sapphire substrates through monolayer h-BN.The field of sapphire can only partially penetrate the bilayer h-BN and result in the mixing of remote epitaxy and van der Waals(vdWs)epitaxy.Due to the weak interfacial scattering and high crystalline quality of ZrS_(2) epilayer,the ZrS_(2) photodetector with monolayer h-BN shows the best performance,with an on/off ratio of more than 2×10^(5) and a responsivity up to 379 mA·W^(-1).This work provides an efficient approach to prepare single-crystal transition metal dichalcogenides and their heterojunctions with h-BN,which have great potential in developing large-area 2D electronic devices.
