In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,cry...In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.展开更多
Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical pr...Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.展开更多
Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecu...Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecular exchange reaction—requires strict control of ambient humidity and immediate thermal annealing treatment,raising manufacturing costs and causing fast nucleation of perovskite films.We report herein a self-buffered molecular migration strategy to slow down the intermolecular exchange reaction by introducing a n-butylammonium bromide shielding layer,which limits moisture diffusion into intermediate-phase film.This further endows the notably wide nucleation time and humidity windows for perovskite crystallization in ambient air.Consequently,the optimized 1.68 e V-bandgap n-i-p structured PSC reaches a record-high reverse-scan(RS)PCE of 22.09%.Furthermore,the versatility and applicability of as-proposed self-buffered molecular migration strategy are certified by employing various shielding materials and 1.53 eV-/1.77 eV-bandgap perovskite materials.The n-i-p structured PSCs based on 1.53 eV-and 1.77 eV-bandgap perovskite films achieve outstanding RS PCEs of 25.23%and 19.09%,respectively,both of which are beyond of the state-of-the-art ambient-air processed PSCs.展开更多
The design of customized crystal plane heterojunction can effectively leverage the optimal anisotropic interaction of crystal plane,thereby enhancing photocatalytic activity.In this study,Co_(3)O_(4) exposed(111),(110...The design of customized crystal plane heterojunction can effectively leverage the optimal anisotropic interaction of crystal plane,thereby enhancing photocatalytic activity.In this study,Co_(3)O_(4) exposed(111),(110),and(100)crystal planes(designated as HCO,NCO,and CCO,respectively)were synthesized and successfully coupled with Cd_(0.5)Zn_(0.5)S(CZS).Among these composites,the HCO/CZS exhibited best hydrogen evolution activity.In conjunction with DFT calculations and femtosecond transient absorption spectroscopy,it has been found that:the crystal plane interaction between HCO and CZS enabled the composite catalyst to exhibit optimal anisotropy in crystal plane carrier transport,crystal plane active sites,and crystal plane electronic structure.This interaction induces a redistribution of electrons at their contact interface,thereby establishing a built-in electric field that facilitates the formation of ohmic heterojunction between HCO and CZS.The synergistic effect of the ohmic heterojunction and crystal plane anisotropy not only decreases the Gibbs free energy of hydrogen adsorption but also facilitates the efficient spatial separation and rapid transfer of electron-hole pairs.This study offers valuable insights into the customization of crystal plane heterojunctions,aiming to maximize anisotropic interactions between crystal planes in order to enhance photocatalytic hydrogen evolution.展开更多
Machine learning has revolutionized many fields,including materials science.However,predicting the properties of crystalline materials using machine learning faces challenges in input encoding,output versatility,and i...Machine learning has revolutionized many fields,including materials science.However,predicting the properties of crystalline materials using machine learning faces challenges in input encoding,output versatility,and interpretability.We introduce Crystal BERT,an adaptable transformer-based framework integrating space group,elemental,and unit cell information.This novel structure can seamlessly combine diverse features and accurately predict various physical properties,including topological properties,superconducting transition temperatures,dielectric constants,and more.Crystal BERT provides insightful interpretations of features influencing target properties.Our results indicate that space group and elemental information are crucial for predicting topological and superconducting properties,underscoring their intricate nature.By incorporating these features,we achieve91%accuracy in topological classification,surpassing prior studies and identifying previously misclassified materials.This research demonstrates that integrating diverse material information enhances the prediction of complex material properties,paving the way for more accurate and interpretable machine learning models in materials science.展开更多
Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operati...Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.展开更多
In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide a...In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna,coupled to photonic crystal waveguide through photonic crystal cavity,and radiated outward through slots at the top layer of antenna.The simulation results show that the antenna achieves a peak gain of 13.45 dBi at 360 GHz,a half-power beam width of 10.9°,and a side lobe level of−13.9 dB.The antenna based on photonic crystal has the advantages of low profile,low loss,and high radiation efficiency,which can be applied to terahertz wireless communication systems.展开更多
The microstructure and related property evolution induced by dynamic recrystallization(DRX)and static recrystallization(SRX)in thermo-mechanical process are two critical factors for the metal forming.The DRX and SRX a...The microstructure and related property evolution induced by dynamic recrystallization(DRX)and static recrystallization(SRX)in thermo-mechanical process are two critical factors for the metal forming.The DRX and SRX are determined by the grain level deformation and sequentially coupled.In order to fully capture the microstructure and mechanical property evolution,a crystal plasticity finite element based modelling method for DRX and SRX is proposed in the current work.The grain level deformation is calculated with crystal plasticity which is coupled with the recrystallization model straightforwardly,and both the grain deformation and microstructure evolution are updated simultaneously.The proposed method is validated with discontinuous DRX experiments and the effects of initial deformation conditions are well-captured.Two controversial mechanisms for recrystallization microstructure evolution,i.e.oriented nucleation and growth selection,are discussed in the current framework with the advantages of accurate grain level deformation and interaction predictions.Furthermore,the sequentially coupled DRX and SRX are modelled seamlessly in the current work which provides a critical method for fully integrated thermo-mechanical processes analysis.展开更多
The samples of single crystal superalloy DD6 are grit blasted and then heat treated either with the standard heat treatment procedure or in the temperature range of 1 000-1 250 ℃ for 4-16 h at vacuum atmosphere, then...The samples of single crystal superalloy DD6 are grit blasted and then heat treated either with the standard heat treatment procedure or in the temperature range of 1 000-1 250 ℃ for 4-16 h at vacuum atmosphere, then the recrystallization behavior of DD6 alloy is investigated. The results show that the equiaxed recrystallization grains form in the 7 phase region where the as-cast γ＇ phases have been dissolved completely, and cellular recrystallization forms in the region where the ascast γ＇ phases have been dissolved partially. The cellular recrystallization area consists of cellular grains, and the cellular grain consists of cubic γ＇ phase, lamellar γ＇ phase and γ＋γ＇. The coexistence of the equiaxed recrystallization zones and cellular recrystallization zones is a re- crystallized characteristic of the cold worked single crystal samples which are heat treated at a temperature lower than the solu- tion temperature. When the heating temperature is higher than 1 150 ℃, with the increase of heat treating temperature, the equiaxed recrystallization zone expands, whereas the cellular recrystallization zone shrinks. All the deformed regions are consumed by equiaxed recrystallization after annealing at solution temperature.展开更多
In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-dept...In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.展开更多
随着量子计算技术的不断发展,依赖传统公钥密码体制三大功能(密钥协商/数字签名/公钥加密)的各种应用系统将不再安全.为应对量子威胁,以美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)为首的国际标准...随着量子计算技术的不断发展,依赖传统公钥密码体制三大功能(密钥协商/数字签名/公钥加密)的各种应用系统将不再安全.为应对量子威胁,以美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)为首的国际标准组织积极征集与部署后量子密码(Post Quantum Cryptography,PQC)算法的标准化工作,致力于在真正实用型量子计算机问世之前,提前完成传统公钥密码算法到PQC算法的迁移过渡.Crystals-Dilithium是NIST-PQC标准中的一种基于格的数字签名算法,其安全性高,运算速度快,是实现抵抗量子攻击数字签名算法的重要路径之一.本文从主流Crystals-Dilithium数字签名算法的理论基础出发,从底层关键组件的优化方法和整体硬件构架设计方法着手,围绕硬件资源优化和性能优化等现有方法和成果对比展开分析介绍,为研究者们后续研究探明方向,希望为设计性能与硬件资源均衡的后量子数字签名密码芯片提供有力参考.展开更多
Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here...Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here,with an in-situ real-time monitoring system for MAPbBr3 PSCs growth during the antisolvent vapor-assisted crystallization(AVC)process,the growth curves of MAPbBr3 PSCs are obtained and the growth kinetics are theoretically modeled.Two important factors,including antisolvent vapor flux and initial precursor concentration,have been investigated experimentally for their impacts on crystal quality.By controlling the antisolvent vapor flux,the nucleation of PSCs at the container-solution interface can be regulated;while by controlling the initial precursor concentration,the crystal quality can be improved.The optimized MAPbBr3 PSCs exhibited significantly high qualities,with the narrowest reported full width at half maximum(0.00637°)of X-ray diffraction rocking curve as reported,a trap-state density as low as 2.12×10^(10 )cm^(−3),and a mobility-lifetime(μτ)product of 1.4×10^(−2) cm^(2) V^(−1).The fabricated X-ray detectors demonstrated optimal performance at an electric field of 20 V/mm,with a sensitivity of 9.02×10^(3)μC Gy^(−1) cm^(−2) and the lowest detectable dose rate of 0.08μGy s^(−1) under irradiation with continuum X-ray energy up to 20 keV.This work provides valuable insights for the development of high-quality PSCs for direct radiation detection.展开更多
For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable sur...For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable surface and interfacial properties.Various single crystal types,including metals,semiconductors,ceramics,organics,and nanocrystals,exhibit superior catalytic selectivity and stability in reactions such as water splitting and carbon/nitrogen cycles,benefiting from high electrical conductivity,tunable energy bands,and active sites with high surface energy.Through surface modification,interfacial atomic doping,and heterostructure construction,the distribution of active sites,electronic structure,and mass transport can be precisely regulated,significantly optimizing the catalytic kinetics of single crystal materials.In situ characterizations elucidate catalytic mechanisms at the atomic scale,while emerging methods like AI-assisted synthesis and bio-template directed growth offer pathways to overcome bottlenecks in the precision and cost of single crystal preparation.In addressing stability challenges in complex environments,strategies such as organic-inorganic hybridization and gradient interface design effectively mitigate interfacial instability.Future research should focus on cross-scale structural regulation and multidisciplinary integration to facilitate the transition of single crystal electrocatalysts from fundamental research to industrial applications,enabling efficient energy conversion.展开更多
We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5...We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5185 nm,b=0.5327 nm,c=0.7378 nm,α=β=90°and V=0.203784 nm3 are obtained by fitting powder X-ray diffraction data.The Mohr's hardnesses along three axes are 6.94,7.27,and 7.44.The thermal expansion coefficient of b axis is 4.20×10^(-6)k^(-1)and the density is 5.88 g/cm3.The thermal conductivities are characterized as K_(a)=6.24,K_(b)=5.57,and K_(c)=6.83 W/(m·K).Meanwhile,the refractive index,absorption and emission spectra in triaxial di-rections are determined.Besides,level lifetimes of 4l11/2 and 413/2 are 0.86 and 2.83 ms.Finally,the~2.7μm multiwavelength laser outputs are observed with maximum average power of 628 mW and beam quality factors M_(x)^(2)/M_(y)^(2) of 1.42/1.45.The results prove that the Er:GYAP crystal is a promising gain medium for generating mid-infrared lasers.展开更多
Photonic crystal surface emitting lasers(PCSELs)utilize the Bragg diffraction of two-dimensional photonic crystals to achieve a single-mode output with a high power and a small divergence angle,and has recently attrac...Photonic crystal surface emitting lasers(PCSELs)utilize the Bragg diffraction of two-dimensional photonic crystals to achieve a single-mode output with a high power and a small divergence angle,and has recently attracted much attention^([1−3]).In 2023,Kyoto University reported GaAs-based 945 nm PCSELs with a continuous-wave(CW)single-mode output power of exceeding 50 W,and a narrow beam divergence angle of 0.05°,demonstrating a brightness of 1 GW·cm^(−2)·sr^(−1),which rivals those of the existing bulky lasers^([4]).展开更多
In this study,a batch of φ12 mm Cs_(2)LiYCl_(6):Ce crystals codoped with different contents of Cu^(+)and Sc^(3+)was successfully grown using the Multi-ampule Bridgeman method.A new emission peaking at 418 nm is found...In this study,a batch of φ12 mm Cs_(2)LiYCl_(6):Ce crystals codoped with different contents of Cu^(+)and Sc^(3+)was successfully grown using the Multi-ampule Bridgeman method.A new emission peaking at 418 nm is found in the photoluminescence spectra of CLYC:Ce codoped with Cu^(+)ion.Codoping Cu^(+)or Sc^(3+)both increases the proportion of intrinsic self-trapped exciton(STE)luminescence,and extends the excitation band of Ce^(3+),especially in Cu^(+)codoped samples,where a new absorption peak at 248 nm can be identified.The light yield of Cu^(+)codoped samples remains largely unchanged,but the energy resolution shows a slight deterioration.Both light yield and energy resolution degrade after Sc^(3+)codoping,and the effect is much severe than that of Cu^(+)codoped samples.X-ray induced afterglow can be suppressed after Cu^(+)codoping and low content of Sc^(3+)codoping.The scintillation decay variation also depends on the codoping ions and their contents.展开更多
Reaction crystallization method is a common cocrystal synthesis approach attributed to the advantage of avoiding individual crystallization of insoluble components,but faces the defects of soluble components precipita...Reaction crystallization method is a common cocrystal synthesis approach attributed to the advantage of avoiding individual crystallization of insoluble components,but faces the defects of soluble components precipitated due to organic solvent volatilization and the formation of unwanted solvates.Our group recently proposed a slurry method based on deep eutectic solvents(DESs)for cocrystal synthesis,which is green,safe and can avoid solvate formation.However,some reactions only produce insoluble raw materials rather than cocrystals due to insufficient activity of the soluble cocrystal co-formers in DESs.Herein,combining the dual benefits of the two methods,a novel reaction crystallization method based on DESs was proposed and employed for cocrystal synthesis of nicotinamide,carbamazepine and theophylline,which can prevent individual crystallization,unwanted solvate formation,and soluble component precipitation,providing a promising alternative for green and efficient synthesis of cocrystals.展开更多
Mg_(x)(Ni_(0.8)La_(0.2))_(100-x),where x=60,70,80,exhibiting a nanocrystalline microstructure,were prepared through the crystallization of amorphous alloys.The investigation encompassed the phase constitution,grain si...Mg_(x)(Ni_(0.8)La_(0.2))_(100-x),where x=60,70,80,exhibiting a nanocrystalline microstructure,were prepared through the crystallization of amorphous alloys.The investigation encompassed the phase constitution,grain size,microstructural stability,and hydrogen storage properties.Crystallization kinetics,along with in-situ high-energy XRD characterization,revealed a concentrated and synchronous crystallization of Mg_(2)Ni and RE-Mg-Ni ternary phases with the increase in La and Ni content.The attributed synchronous crystallization process was found to be a result of the close local affinity of Mg_(2)Ni and RE-Mg-Ni ternary phases,as assessed by the thermodynamic Miedema model.Significant secondary phase pinning effect,arising from the high likelihood of well-matching phase structures between Mg_(2)Ni,LaMg_(2)Ni,and LaMgNi_(4),was validated through both the edge-to-edge matching model prediction and experimental observation.Thefine and homogeneous microstructure was shown to be a consequence of fast crystallization kinetics and the secondary phase pinning effect.Improved activation performance and cycling stability were observed,stemming from grain refinement and excellent microstructural stability.Our study provides insights into mechanism of grain refinement of nanocrystalline microstructure tailored by phase constitution and crystallization kinetics in the amorphous-crystallization route.We also demonstrate the potential of material design guided by phase equilibria and crystallographic predictions to improve nanocrystalline with excellent microstructural stability.展开更多
Poly(L-lactic acid)(PLLA)has been widely concerned because of its excellent biodegradability and biocompatibility.However,the poor crystallization ability of PLLA during the molding process not only leads to weak mech...Poly(L-lactic acid)(PLLA)has been widely concerned because of its excellent biodegradability and biocompatibility.However,the poor crystallization ability of PLLA during the molding process not only leads to weak mechanical properties but also reduces the processing efficiency,which limits the application of PLLA greatly.Enhancing crystallization ability of PLLA via introducing inorganic nanoparticles usually sacrifices biodegradability or transparency.Here,the microfine fibers with stereocomplex(SC)crystallites were incorporated into PLLA film to tailor the crystallization ability of PLLA as well as the mechanical properties.The results confirmed that the crystallization ability of PLLA matrix under different circumstances could be greatly enhanced by a few amounts of SC crystalline fibers,and synchronously enhanced tensile strength and ductility were also achieved,especially at relatively high temperature.Due to the relatively homogeneous dispersion of SC crystalline fibers and the similar refractive index between components,the PLLA-based film also exhibited high transparency,up to 85%-90%depending on the content of SC crystalline fibers.This work provides guidance for manufacturing transparent PLLA-based packaging materials with good crystallization capability and mechanical properties.展开更多
Based on the relationship between deformation microstructures and grain orientations,three characteristic Cu single crystals were used to investigate the opposite effects of ultrasonic superimposed high-strain-rate on...Based on the relationship between deformation microstructures and grain orientations,three characteristic Cu single crystals were used to investigate the opposite effects of ultrasonic superimposed high-strain-rate on the dislocation motion during ultrasonic welding(UW).The results revealed that equiaxed dislocation cells and discontinuous dynamic recrystallization(DRX)grains dominated in the joint microstructures.Three Cu single crystal joints exhibited an isotropic trend in grain orientation,welding quality,and microscopic mechanical properties.The preferred dislocation behaviors and DRX modes were further analyzed by modelling the stored energy difference,indicating that high mobility of intra-granular dislocations and homogeneous dislocation motion induced by the ultrasonic excitation were the intrinsic factors contributing to the formation of isotropic microstructures and welding quality.展开更多
基金Funded by the National Key Research Program(No.2024-1129-954-112)National Natural Science Foundation of China(No.52372033)Guangxi Science and Technology Major Program(No.AA24263054)。
文摘In current research,Li_(2)O-Al_(2)O_(3)-SiO_(2)glass-ceramics were prepared by conventional meltquenching and subsequent heat treatment method.The effect of Al_(2)O_(3)content on microstructures,thermal properties,crystallization behaviours and mechanical properties were investigated.FTIR,Raman spectroscopy and nuclear magnetic resonance spectroscopy microstructure analysis showed that the silico-oxygen network was damaged,while the increase of[AlO_(4)]content repaired the glass network,and finally made the glass network have better connectivity,with the decrease of SiO_(2).The thermal analysis confirmed the increasing glass transition and crystallization temperatures from growing Al_(2)O_(3)content.In addition,different crystal phases can be precipitated in the glass matrix,such as LiAlSi_(4)O_(10),Li_(2)Si_(2)O_(5) in glass with low Al_(2)O_(3)content,the combination of Li_xAl_xSi_(1-x)O_(2),LiAlSi_(3)O_(8),Li_(2)SiO_(3)in glass with intermediate Al_(2)O_(3)content,and the combination of LiAlSi_(2)O_(6),SiO_(2)in glass with high Al_(2)O_(3)content.The hardness of as-prepared glass gradually increases with the increase of the Al_(2)O_(3)content.The Vickers hardness of the glass-ceramics is highly dependent on the Al_(2)O_(3)content in the glass and the heat treatment temperatures,reaching a maximum of 10.11 GPa.Scanning electron microscope images show that the crystals change from spherical to massive and finally to sheet.The change of glass structure,crystal phase and morphology is the main reason for the different mechanical properties.
基金Funded by Shandong Provincial Youth Innovation Team Development Plan of Colleges and Universities(No.2022KJ100)National Natural Science Foundation of China(No.52172019)。
文摘Waste glass fibers were used as the main raw materials to prepare foamed glass-ceramics with 0-14 wt%H_(3)BO_(3)as a flux agent.The effects of H_(3)BO_(3)on the crystallization process,foaming behavior,and physical properties of CaO-MgO-Al_(2)O_(3)-SiO_(2)foamed glass-ceramics were investigated.The results showed that the main crystalline phase of the foamed glass-ceramics was anorthite with diopside as a minor crystalline phase,which exhibited a typical surface crystallization process.The addition of H_(3)BO_(3)modified the surface of glass powders and inhibited crystal precipitation obviously.The low melting point of H_(3)BO_(3)and the decrease of crystallinity jointly promoted the growth of pores,resulting in a reduction of bulk density and an increase in porosity.The compressive strength and thermal conductivity of the samples were linearly related to the bulk density.In particular,the sample added with 10 wt%H_(3)BO_(3)exhibited excellent properties,possessing a low coefficient of thermal conductivity 0.081 W/(m·K)and relatively high compressive strength 3.36 MPa.
基金the financial support from the National Key R&D Program of China(2021YFF0500500)the National Natural Science Foundation of China(62474131,62274132,and 62204189)。
文摘Ambient-air,moisture-assisted annealing is widely used in fabricating perovskite solar cells(PSCs).However,the inherent sensitivity of perovskite intermediate-phase to moisture—due to fast and spontaneous intermolecular exchange reaction—requires strict control of ambient humidity and immediate thermal annealing treatment,raising manufacturing costs and causing fast nucleation of perovskite films.We report herein a self-buffered molecular migration strategy to slow down the intermolecular exchange reaction by introducing a n-butylammonium bromide shielding layer,which limits moisture diffusion into intermediate-phase film.This further endows the notably wide nucleation time and humidity windows for perovskite crystallization in ambient air.Consequently,the optimized 1.68 e V-bandgap n-i-p structured PSC reaches a record-high reverse-scan(RS)PCE of 22.09%.Furthermore,the versatility and applicability of as-proposed self-buffered molecular migration strategy are certified by employing various shielding materials and 1.53 eV-/1.77 eV-bandgap perovskite materials.The n-i-p structured PSCs based on 1.53 eV-and 1.77 eV-bandgap perovskite films achieve outstanding RS PCEs of 25.23%and 19.09%,respectively,both of which are beyond of the state-of-the-art ambient-air processed PSCs.
文摘The design of customized crystal plane heterojunction can effectively leverage the optimal anisotropic interaction of crystal plane,thereby enhancing photocatalytic activity.In this study,Co_(3)O_(4) exposed(111),(110),and(100)crystal planes(designated as HCO,NCO,and CCO,respectively)were synthesized and successfully coupled with Cd_(0.5)Zn_(0.5)S(CZS).Among these composites,the HCO/CZS exhibited best hydrogen evolution activity.In conjunction with DFT calculations and femtosecond transient absorption spectroscopy,it has been found that:the crystal plane interaction between HCO and CZS enabled the composite catalyst to exhibit optimal anisotropy in crystal plane carrier transport,crystal plane active sites,and crystal plane electronic structure.This interaction induces a redistribution of electrons at their contact interface,thereby establishing a built-in electric field that facilitates the formation of ohmic heterojunction between HCO and CZS.The synergistic effect of the ohmic heterojunction and crystal plane anisotropy not only decreases the Gibbs free energy of hydrogen adsorption but also facilitates the efficient spatial separation and rapid transfer of electron-hole pairs.This study offers valuable insights into the customization of crystal plane heterojunctions,aiming to maximize anisotropic interactions between crystal planes in order to enhance photocatalytic hydrogen evolution.
基金supported by the Natural Science Foundation of China(Grant Nos.12350404 and 12174066)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302600)+2 种基金the Science and Technology Commission of Shanghai Municipality(Grant Nos.23JC1400600,24LZ1400100,and 2019SHZDZX01)sponsored by“Shuguang Program”supported by Shanghai Education Development FoundationShanghai Municipal Education Commission。
文摘Machine learning has revolutionized many fields,including materials science.However,predicting the properties of crystalline materials using machine learning faces challenges in input encoding,output versatility,and interpretability.We introduce Crystal BERT,an adaptable transformer-based framework integrating space group,elemental,and unit cell information.This novel structure can seamlessly combine diverse features and accurately predict various physical properties,including topological properties,superconducting transition temperatures,dielectric constants,and more.Crystal BERT provides insightful interpretations of features influencing target properties.Our results indicate that space group and elemental information are crucial for predicting topological and superconducting properties,underscoring their intricate nature.By incorporating these features,we achieve91%accuracy in topological classification,surpassing prior studies and identifying previously misclassified materials.This research demonstrates that integrating diverse material information enhances the prediction of complex material properties,paving the way for more accurate and interpretable machine learning models in materials science.
基金the Natural Science Foundation of Jiangsu Province(No.BK20240679)National Natural Science Foundation of China(No.22101134)are greatly acknowledged。
文摘Traditional desorption methods in porous sorbents rely heavily on energy-intensive processes such as heating,vacuum pumping,or inert gas purging[1].While effective,these approaches incur substantial energy and operational costs,particularly for hydrocarbons with high boiling points or strong host-vip interactions[2].This is the same case in the newly-developed macrocyclebased crystalline adsorbents,namely nonporous adaptive crystals(NACs).To address these challenges,a recent study published in Angewandte Chemie International Edition by Jie,Ma,and co-workers reported an innovative molecular-"squeeze"triggered desorption mechanism in NACs[3-5].Specifically,ethyl acetate(EA)triggers vip desorption without penetrating the crystal pores or voids.Instead,EA molecules interact with the crystal surface through supramolecular forces,causing the adaptive closure of voids and the subsequent release of vip molecules.Unlike conventional sponges that rely on mechanical squeeze to deform themselves in the bulk for vip release,these macrocycle crystals undergo structural deformation at the molecular level and condensed phase when exposed to vaporized molecules.Because of the similar behavior between sponges and such NACs,the authors name them as sponge-likemacrocyclecrystals.
基金supported by the National Natural Science Foundation of China(No.62375031)the Basic Research Project of Chongqing Science and Technology Commission(No.CSTC-2021jcyj-bsh0194)the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJQN202200602)。
文摘In this paper,a terahertz slotted waveguide array antenna is designed based on photonic crystal,which can realize efficient radiation of terahertz waves.The electromagnetic wave is fed from the rectangular waveguide at the bottom of the antenna,coupled to photonic crystal waveguide through photonic crystal cavity,and radiated outward through slots at the top layer of antenna.The simulation results show that the antenna achieves a peak gain of 13.45 dBi at 360 GHz,a half-power beam width of 10.9°,and a side lobe level of−13.9 dB.The antenna based on photonic crystal has the advantages of low profile,low loss,and high radiation efficiency,which can be applied to terahertz wireless communication systems.
基金supported by the National Natural Science Foundation of China(Nos.52105384 and U2141215).
文摘The microstructure and related property evolution induced by dynamic recrystallization(DRX)and static recrystallization(SRX)in thermo-mechanical process are two critical factors for the metal forming.The DRX and SRX are determined by the grain level deformation and sequentially coupled.In order to fully capture the microstructure and mechanical property evolution,a crystal plasticity finite element based modelling method for DRX and SRX is proposed in the current work.The grain level deformation is calculated with crystal plasticity which is coupled with the recrystallization model straightforwardly,and both the grain deformation and microstructure evolution are updated simultaneously.The proposed method is validated with discontinuous DRX experiments and the effects of initial deformation conditions are well-captured.Two controversial mechanisms for recrystallization microstructure evolution,i.e.oriented nucleation and growth selection,are discussed in the current framework with the advantages of accurate grain level deformation and interaction predictions.Furthermore,the sequentially coupled DRX and SRX are modelled seamlessly in the current work which provides a critical method for fully integrated thermo-mechanical processes analysis.
文摘The samples of single crystal superalloy DD6 are grit blasted and then heat treated either with the standard heat treatment procedure or in the temperature range of 1 000-1 250 ℃ for 4-16 h at vacuum atmosphere, then the recrystallization behavior of DD6 alloy is investigated. The results show that the equiaxed recrystallization grains form in the 7 phase region where the as-cast γ＇ phases have been dissolved completely, and cellular recrystallization forms in the region where the ascast γ＇ phases have been dissolved partially. The cellular recrystallization area consists of cellular grains, and the cellular grain consists of cubic γ＇ phase, lamellar γ＇ phase and γ＋γ＇. The coexistence of the equiaxed recrystallization zones and cellular recrystallization zones is a re- crystallized characteristic of the cold worked single crystal samples which are heat treated at a temperature lower than the solu- tion temperature. When the heating temperature is higher than 1 150 ℃, with the increase of heat treating temperature, the equiaxed recrystallization zone expands, whereas the cellular recrystallization zone shrinks. All the deformed regions are consumed by equiaxed recrystallization after annealing at solution temperature.
基金supported by Natural Science Foundation of Shandong Province(Nos.ZR2022YQ42,ZR2021JQ15,ZR2021QE011,ZR2021ZD20,2022GJJLJRC-01)Innovative Team Project of Jinan(No.2021GXRC019)the National Natural Science Foundation of China(Nos.52022037,52202366).
文摘In contrast to research on active sites in nanomaterials,lithium tantalate single crystals,known for their exceptional optical properties and long-range ordered lattice structure,present a promising avenue for in-depth exploration of photocatalytic reaction systems with fewer constraints imposed by surface chemistry.Typically,the isotropy of a specific facet provides a perfect support for studying heteroatom doping.Herein,this work delves into the intrinsic catalytic sites for photocatalytic nitrogen fixation in iron-doped lithium tantalate single crystals.The presence of iron not only modifies the electronic structure of lithium tantalate,improving its light absorption capacity,but also functions as an active site for the nitrogen adsorption and activation.The photocatalytic ammonia production rate of the iron-doped lithium tantalate in pure water is maximum 26.95μg cm^(−2)h^(−1),which is three times higher than that of undoped lithium tantalate.The combination of first-principles simulations with in situ characterizations confirms that iron doping promotes the rate-determining step and changes the pathway of hydrogenation to associative alternating.This study provides a new perspective on in-depth investigation of intrinsic catalytic active sites in photocatalysis and other catalytic processes.
文摘随着量子计算技术的不断发展,依赖传统公钥密码体制三大功能(密钥协商/数字签名/公钥加密)的各种应用系统将不再安全.为应对量子威胁,以美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)为首的国际标准组织积极征集与部署后量子密码(Post Quantum Cryptography,PQC)算法的标准化工作,致力于在真正实用型量子计算机问世之前,提前完成传统公钥密码算法到PQC算法的迁移过渡.Crystals-Dilithium是NIST-PQC标准中的一种基于格的数字签名算法,其安全性高,运算速度快,是实现抵抗量子攻击数字签名算法的重要路径之一.本文从主流Crystals-Dilithium数字签名算法的理论基础出发,从底层关键组件的优化方法和整体硬件构架设计方法着手,围绕硬件资源优化和性能优化等现有方法和成果对比展开分析介绍,为研究者们后续研究探明方向,希望为设计性能与硬件资源均衡的后量子数字签名密码芯片提供有力参考.
基金supported by the National Key Research and Development Program of China(No.2020YFB2206103)the Na-tional Natural Science Foundation(Nos.61975196,62274160,and 62250010)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB43020100)the Youth Innova-tion Promotion Association of the Chinese Academy of Sciences(2021111).
文摘Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here,with an in-situ real-time monitoring system for MAPbBr3 PSCs growth during the antisolvent vapor-assisted crystallization(AVC)process,the growth curves of MAPbBr3 PSCs are obtained and the growth kinetics are theoretically modeled.Two important factors,including antisolvent vapor flux and initial precursor concentration,have been investigated experimentally for their impacts on crystal quality.By controlling the antisolvent vapor flux,the nucleation of PSCs at the container-solution interface can be regulated;while by controlling the initial precursor concentration,the crystal quality can be improved.The optimized MAPbBr3 PSCs exhibited significantly high qualities,with the narrowest reported full width at half maximum(0.00637°)of X-ray diffraction rocking curve as reported,a trap-state density as low as 2.12×10^(10 )cm^(−3),and a mobility-lifetime(μτ)product of 1.4×10^(−2) cm^(2) V^(−1).The fabricated X-ray detectors demonstrated optimal performance at an electric field of 20 V/mm,with a sensitivity of 9.02×10^(3)μC Gy^(−1) cm^(−2) and the lowest detectable dose rate of 0.08μGy s^(−1) under irradiation with continuum X-ray energy up to 20 keV.This work provides valuable insights for the development of high-quality PSCs for direct radiation detection.
基金supported by National Natural Science Foundation of China(No.52202366)Taishan Scholar Project of Shandong Province(tstp20240515,tsqn202312217)+1 种基金Natural Science Foundation of Shandong Province(China,No.2025HWYQ-050,ZR2021QE011,ZR2022QH072,ZR2021QE284)the King Abdullah University of Science and Technology,the Center of Excellence for Renewable Energy and Storage Technologies.
文摘For emerging renewable and sustainable energy technologies,single crystal materials have become key materials to enhance electrocatalytic performance because of their atomic-level ordered structures and tailorable surface and interfacial properties.Various single crystal types,including metals,semiconductors,ceramics,organics,and nanocrystals,exhibit superior catalytic selectivity and stability in reactions such as water splitting and carbon/nitrogen cycles,benefiting from high electrical conductivity,tunable energy bands,and active sites with high surface energy.Through surface modification,interfacial atomic doping,and heterostructure construction,the distribution of active sites,electronic structure,and mass transport can be precisely regulated,significantly optimizing the catalytic kinetics of single crystal materials.In situ characterizations elucidate catalytic mechanisms at the atomic scale,while emerging methods like AI-assisted synthesis and bio-template directed growth offer pathways to overcome bottlenecks in the precision and cost of single crystal preparation.In addressing stability challenges in complex environments,strategies such as organic-inorganic hybridization and gradient interface design effectively mitigate interfacial instability.Future research should focus on cross-scale structural regulation and multidisciplinary integration to facilitate the transition of single crystal electrocatalysts from fundamental research to industrial applications,enabling efficient energy conversion.
基金the National Natural Science Foundation of China(52102012)Natural Science Foundation of Anhui Province(2208085QF217)the Fundamental Research Funds for the Central Universities(WK5290000004)。
文摘We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5185 nm,b=0.5327 nm,c=0.7378 nm,α=β=90°and V=0.203784 nm3 are obtained by fitting powder X-ray diffraction data.The Mohr's hardnesses along three axes are 6.94,7.27,and 7.44.The thermal expansion coefficient of b axis is 4.20×10^(-6)k^(-1)and the density is 5.88 g/cm3.The thermal conductivities are characterized as K_(a)=6.24,K_(b)=5.57,and K_(c)=6.83 W/(m·K).Meanwhile,the refractive index,absorption and emission spectra in triaxial di-rections are determined.Besides,level lifetimes of 4l11/2 and 413/2 are 0.86 and 2.83 ms.Finally,the~2.7μm multiwavelength laser outputs are observed with maximum average power of 628 mW and beam quality factors M_(x)^(2)/M_(y)^(2) of 1.42/1.45.The results prove that the Er:GYAP crystal is a promising gain medium for generating mid-infrared lasers.
基金funded by National Key R&D Program of China(Grant Nos.2024YFB3612200,2023YFB3609601,2022YFB3604300,2022YFB2802801,2022YFB3604802)Natural Science Foundation of China(Grant Nos.U24A20300,62174174,62274177,62275263,62325406,62374172,62304242,62304240,62404241)+4 种基金Youth Innovation Promotion Association of CAS(Grant Nos.2022323 and 2022324)Key R&D Program of Jiangsu Province(Grant No.BE2023018-2)Basic Research Program of Jiangsu(Grant No.BK20240126)Suzhou Science and Technology Program(Grant Nos.SYC2022089,ZXL2024379,and ZXL2024376)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A1515110482 and 2022A1515110004).
文摘Photonic crystal surface emitting lasers(PCSELs)utilize the Bragg diffraction of two-dimensional photonic crystals to achieve a single-mode output with a high power and a small divergence angle,and has recently attracted much attention^([1−3]).In 2023,Kyoto University reported GaAs-based 945 nm PCSELs with a continuous-wave(CW)single-mode output power of exceeding 50 W,and a narrow beam divergence angle of 0.05°,demonstrating a brightness of 1 GW·cm^(−2)·sr^(−1),which rivals those of the existing bulky lasers^([4]).
基金Project supported by the National Key Research and Development Program,China(2022YFB3503600)Manned Space Station Engineering Space Science and Applications Program(MSAP)(ZDBS-ZRKJZTLC011)+3 种基金National Natural Science Foundation of China,China(11975303,12211530561,12305211)Shanghai Municipal Natural Science Foundation,China(21TS1400100)CAS Cooperative Research Project(121631KYSB20210017)CAS Project for Young Scientist in Basic Research(YSBR-024)。
文摘In this study,a batch of φ12 mm Cs_(2)LiYCl_(6):Ce crystals codoped with different contents of Cu^(+)and Sc^(3+)was successfully grown using the Multi-ampule Bridgeman method.A new emission peaking at 418 nm is found in the photoluminescence spectra of CLYC:Ce codoped with Cu^(+)ion.Codoping Cu^(+)or Sc^(3+)both increases the proportion of intrinsic self-trapped exciton(STE)luminescence,and extends the excitation band of Ce^(3+),especially in Cu^(+)codoped samples,where a new absorption peak at 248 nm can be identified.The light yield of Cu^(+)codoped samples remains largely unchanged,but the energy resolution shows a slight deterioration.Both light yield and energy resolution degrade after Sc^(3+)codoping,and the effect is much severe than that of Cu^(+)codoped samples.X-ray induced afterglow can be suppressed after Cu^(+)codoping and low content of Sc^(3+)codoping.The scintillation decay variation also depends on the codoping ions and their contents.
基金financially supported by National Natural Science Foundation of China(Nos.22101204 and 22271220)the project grant from the Innovation and Strengthening Project of Guangdong Pharmaceutical University-Special Project of the Guangdong Education Commission(No.2020KZDZX1128)+1 种基金the Research Projects of the Chinese Medicine Council of Guangdong Province(No.20231209)the Key Laboratory of Tropical Medicinal Resource Chemistry of the Ministry of Education at Hainan Normal University(No.RDZH2023001)。
文摘Reaction crystallization method is a common cocrystal synthesis approach attributed to the advantage of avoiding individual crystallization of insoluble components,but faces the defects of soluble components precipitated due to organic solvent volatilization and the formation of unwanted solvates.Our group recently proposed a slurry method based on deep eutectic solvents(DESs)for cocrystal synthesis,which is green,safe and can avoid solvate formation.However,some reactions only produce insoluble raw materials rather than cocrystals due to insufficient activity of the soluble cocrystal co-formers in DESs.Herein,combining the dual benefits of the two methods,a novel reaction crystallization method based on DESs was proposed and employed for cocrystal synthesis of nicotinamide,carbamazepine and theophylline,which can prevent individual crystallization,unwanted solvate formation,and soluble component precipitation,providing a promising alternative for green and efficient synthesis of cocrystals.
基金supported by National Natural Science Foundation of China(51761034,51961032,51962028 and 52261041)Innovation Foundation of Inner Mongolia University of Science and Technology(2019YQL03)+2 种基金Major Science and Technology Project of Inner Mongolia(2021ZD0029)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT23005,NJYT23007)Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(NMGIRT2401).
文摘Mg_(x)(Ni_(0.8)La_(0.2))_(100-x),where x=60,70,80,exhibiting a nanocrystalline microstructure,were prepared through the crystallization of amorphous alloys.The investigation encompassed the phase constitution,grain size,microstructural stability,and hydrogen storage properties.Crystallization kinetics,along with in-situ high-energy XRD characterization,revealed a concentrated and synchronous crystallization of Mg_(2)Ni and RE-Mg-Ni ternary phases with the increase in La and Ni content.The attributed synchronous crystallization process was found to be a result of the close local affinity of Mg_(2)Ni and RE-Mg-Ni ternary phases,as assessed by the thermodynamic Miedema model.Significant secondary phase pinning effect,arising from the high likelihood of well-matching phase structures between Mg_(2)Ni,LaMg_(2)Ni,and LaMgNi_(4),was validated through both the edge-to-edge matching model prediction and experimental observation.Thefine and homogeneous microstructure was shown to be a consequence of fast crystallization kinetics and the secondary phase pinning effect.Improved activation performance and cycling stability were observed,stemming from grain refinement and excellent microstructural stability.Our study provides insights into mechanism of grain refinement of nanocrystalline microstructure tailored by phase constitution and crystallization kinetics in the amorphous-crystallization route.We also demonstrate the potential of material design guided by phase equilibria and crystallographic predictions to improve nanocrystalline with excellent microstructural stability.
基金supported by the Sichuan Science and Technology Program(No.2023ZHCG0050)the China Postdoctoral Science Foundation(No.2023M742883)+2 种基金the Science and Technology Innovation Fund for Basic Scientific Research Operating Expenses of Central Universities(No.2682023CX002)the New Interdisciplinary Cultivation Fund of SWJTU(No.2682022KJ040)SEM characterizations were supported by the Analytical and Testing Center of Southwest Jiaotong University。
文摘Poly(L-lactic acid)(PLLA)has been widely concerned because of its excellent biodegradability and biocompatibility.However,the poor crystallization ability of PLLA during the molding process not only leads to weak mechanical properties but also reduces the processing efficiency,which limits the application of PLLA greatly.Enhancing crystallization ability of PLLA via introducing inorganic nanoparticles usually sacrifices biodegradability or transparency.Here,the microfine fibers with stereocomplex(SC)crystallites were incorporated into PLLA film to tailor the crystallization ability of PLLA as well as the mechanical properties.The results confirmed that the crystallization ability of PLLA matrix under different circumstances could be greatly enhanced by a few amounts of SC crystalline fibers,and synchronously enhanced tensile strength and ductility were also achieved,especially at relatively high temperature.Due to the relatively homogeneous dispersion of SC crystalline fibers and the similar refractive index between components,the PLLA-based film also exhibited high transparency,up to 85%-90%depending on the content of SC crystalline fibers.This work provides guidance for manufacturing transparent PLLA-based packaging materials with good crystallization capability and mechanical properties.
基金supported by the National Natural Science Foundation of China(Nos.52175310,52232004)the Launch Research Program of Fuzhou University,China(No.XRC-23083)+1 种基金the Education&Research Project of Fujian Province,China(No.JAT231003)the Open Test Fund for Valuable Instruments and Equipment of Fuzhou University,China(No.2024T036).
文摘Based on the relationship between deformation microstructures and grain orientations,three characteristic Cu single crystals were used to investigate the opposite effects of ultrasonic superimposed high-strain-rate on the dislocation motion during ultrasonic welding(UW).The results revealed that equiaxed dislocation cells and discontinuous dynamic recrystallization(DRX)grains dominated in the joint microstructures.Three Cu single crystal joints exhibited an isotropic trend in grain orientation,welding quality,and microscopic mechanical properties.The preferred dislocation behaviors and DRX modes were further analyzed by modelling the stored energy difference,indicating that high mobility of intra-granular dislocations and homogeneous dislocation motion induced by the ultrasonic excitation were the intrinsic factors contributing to the formation of isotropic microstructures and welding quality.
