Accurately predicting the mechanical behavior of pure metals at different radiation doses and prescribing the microstructure evolutions,such as the dislocation structures,remain challenging.This work introduces a 3D h...Accurately predicting the mechanical behavior of pure metals at different radiation doses and prescribing the microstructure evolutions,such as the dislocation structures,remain challenging.This work introduces a 3D hybrid numerical simulation scheme that integrates finite element(FE)and finite difference(FD)modules.The FE module is used to implement the crystal plasticity model,while the FD module is used to solve the reaction-diffusion model regarding dislocation nucleation and transportation.Our hybrid model successfully replicates the mechanical behavior of pristine Cu single crystals and provides details of dislocation cell structures that agree with the experimental observation.Furthermore,the model effectively reflects the irradiation hardening effects for Cu single crystals and demonstrates the formation of dislocation channels and shear band type of strain localization.Our work offers an effective approach for predicting the mechanical responses and the safety evaluation of pure metals in extreme working conditions.展开更多
Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homog...Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homogenous distribution of nanomaterials,which is essential for enhancing their performance while also reducing production costs.In this work,we achieve uniform and stable dispersion of various nano-materials through the confinement effect generated by the stereocomplex cross-linked network formed by the combination of poly(L-lactic)acid and poly(D-lactic)acid.The unique confinement effect of poly-lactic acid(PLA)isomers is universal and significantly enhances the dispersion of nanomaterials in both PLA solutions and films.To demonstrate the efficacy of our approach,we disperse aggregation-induced emission(AIE)molecules within PLA,which leads to the production of PLA films exhibiting improved fluorescence property.This work provides an effective solution for the preparation of nanocomposite ma-terials that are both high-performing and cost-efficient.展开更多
Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphen...Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphene is therefore highly desired yet still suffers from a slow growth rate and poor layer uniformity.Meanwhile,graphene wrinkles,including folds and ripples,form during cooling due to the thermal contraction mismatch between graphene and the metal substrates,and have been far from suppressed or eliminated,especially in bilayer graphene,which would greatly degrade the extraordinary properties of graphene.Here we report the ultrafast growth of wafer-scale fold-free bilayer graphene by chemical vapor deposition.Through well-tuning the alloy thickness and strain regulation of the single-crystal CuNi(111)/sapphire,the full coverage of a 2-inch fold-free bilayer graphene wafer via mainly isothermal segregation has been achieved as fast as 30 s.The tensile-strained CuNi(111)film reduces the thermal contraction mismatch and suppresses the formation of graphene folds during cooling,which is directly observed through in situ optical microscopy.The ultraflat bilayer graphene exhibits wafer-scale uniformity in electrical performance and enhanced mechanical property comparable to the exfoliated ones.Our results offer a promising route for largescale production of bilayer graphene and enable its various applications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12325202,12172005,and 11988102)。
文摘Accurately predicting the mechanical behavior of pure metals at different radiation doses and prescribing the microstructure evolutions,such as the dislocation structures,remain challenging.This work introduces a 3D hybrid numerical simulation scheme that integrates finite element(FE)and finite difference(FD)modules.The FE module is used to implement the crystal plasticity model,while the FD module is used to solve the reaction-diffusion model regarding dislocation nucleation and transportation.Our hybrid model successfully replicates the mechanical behavior of pristine Cu single crystals and provides details of dislocation cell structures that agree with the experimental observation.Furthermore,the model effectively reflects the irradiation hardening effects for Cu single crystals and demonstrates the formation of dislocation channels and shear band type of strain localization.Our work offers an effective approach for predicting the mechanical responses and the safety evaluation of pure metals in extreme working conditions.
基金supported by the National Key R&D Program of China(No.2022YFB3804204)the National Natural Science Foundation of China(Nos.52127805,52102090,12172005,and 12325202)+1 种基金the Fundamental Research Funds for the Central Uni-versities(No.2232022D-04)the Innovation and Development Sup-port Plan for Key Industries in Southern Xinjiang(No.2022DB011).
文摘Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homogenous distribution of nanomaterials,which is essential for enhancing their performance while also reducing production costs.In this work,we achieve uniform and stable dispersion of various nano-materials through the confinement effect generated by the stereocomplex cross-linked network formed by the combination of poly(L-lactic)acid and poly(D-lactic)acid.The unique confinement effect of poly-lactic acid(PLA)isomers is universal and significantly enhances the dispersion of nanomaterials in both PLA solutions and films.To demonstrate the efficacy of our approach,we disperse aggregation-induced emission(AIE)molecules within PLA,which leads to the production of PLA films exhibiting improved fluorescence property.This work provides an effective solution for the preparation of nanocomposite ma-terials that are both high-performing and cost-efficient.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172005,11988102,and 11890681)the National Key R&D Program of China(Grant Nos.2022YFB3806100 and 2020YFE0204200).
基金This work was supported by the National Natural Science Foundation of China(Nos.52021006,T2188101,and 22105009)Beijing National Laboratory for Molecular Sciences(No.BNLMSCXTD-202001)+1 种基金the Tencent Foundation(No.XPLORER PRIZE)We acknowledge Molecular Materials and Nanofabrication Laboratory(MMNL)in the College of Chemistry at Peking University for the use of instruments.
文摘Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphene is therefore highly desired yet still suffers from a slow growth rate and poor layer uniformity.Meanwhile,graphene wrinkles,including folds and ripples,form during cooling due to the thermal contraction mismatch between graphene and the metal substrates,and have been far from suppressed or eliminated,especially in bilayer graphene,which would greatly degrade the extraordinary properties of graphene.Here we report the ultrafast growth of wafer-scale fold-free bilayer graphene by chemical vapor deposition.Through well-tuning the alloy thickness and strain regulation of the single-crystal CuNi(111)/sapphire,the full coverage of a 2-inch fold-free bilayer graphene wafer via mainly isothermal segregation has been achieved as fast as 30 s.The tensile-strained CuNi(111)film reduces the thermal contraction mismatch and suppresses the formation of graphene folds during cooling,which is directly observed through in situ optical microscopy.The ultraflat bilayer graphene exhibits wafer-scale uniformity in electrical performance and enhanced mechanical property comparable to the exfoliated ones.Our results offer a promising route for largescale production of bilayer graphene and enable its various applications.
