Based on machine learning,the high-dimensional fitting of potential energy surfaces under the framework of first principles provides density-functional accuracy of atomic interaction potential for high-precision and l...Based on machine learning,the high-dimensional fitting of potential energy surfaces under the framework of first principles provides density-functional accuracy of atomic interaction potential for high-precision and large-scale simulation of alloy materials.In this paper,we obtained the high-dimensional neural network(NN)potential function of uranium metal by training a large amount of first-principles calculated data.The lattice constants of uranium metal with different crystal structures,the elastic constants,and the anisotropy of lattice expansion of alpha-uranium obtained based on this potential function are highly consistent with first-principles calculation or experimental data.In addition,the calculated formation energy of vacancies in alpha-and beta-uranium also matches the first-principles calculation.The calculated site of the most stable self-interstitial and its formation energy is in good agreement with the findings from density functional theory(DFT)calculations.These results show that our potential function can be used for further large-scale molecular dynamics simulation studies of uranium metal at low pressures,and provides the basis for further construction of potential model suitable for a wide range of pressures.展开更多
Using the experimental results given in literatures about the contact angle, θ and the work of adhesion, W, for nonreactive liquid metal / solid UO_2 systems, the validity and feasibility of the different existing mo...Using the experimental results given in literatures about the contact angle, θ and the work of adhesion, W, for nonreactive liquid metal / solid UO_2 systems, the validity and feasibility of the different existing models for calculating W in the metal /ox- ide systems are discussed. It can be shown that the models assuming that only metal atom-oxygen ion interactions existing at the interfaces are unable to explain the experimental results for W. More reasonable model should take into account both metal atom-oxygen ion and metal atom-oxide metal cation interactions, the proportion of the latter is balanced by the stoichiometry of the oxide. By applying the model recently set up by the authors for binary alloy / oxide systems, one can use the experimental and calculated values of θ and W for various metal / UO_2 systems to predict the influence of metallic additions on the contact angle and the work of adhesion of a given metal / UO_2 system.展开更多
基金Beijing Computational Science Research Center(CSRC)the National Natural Science Foundation of China(Grant Nos.52161160330 and U2230402)。
文摘Based on machine learning,the high-dimensional fitting of potential energy surfaces under the framework of first principles provides density-functional accuracy of atomic interaction potential for high-precision and large-scale simulation of alloy materials.In this paper,we obtained the high-dimensional neural network(NN)potential function of uranium metal by training a large amount of first-principles calculated data.The lattice constants of uranium metal with different crystal structures,the elastic constants,and the anisotropy of lattice expansion of alpha-uranium obtained based on this potential function are highly consistent with first-principles calculation or experimental data.In addition,the calculated formation energy of vacancies in alpha-and beta-uranium also matches the first-principles calculation.The calculated site of the most stable self-interstitial and its formation energy is in good agreement with the findings from density functional theory(DFT)calculations.These results show that our potential function can be used for further large-scale molecular dynamics simulation studies of uranium metal at low pressures,and provides the basis for further construction of potential model suitable for a wide range of pressures.
文摘Using the experimental results given in literatures about the contact angle, θ and the work of adhesion, W, for nonreactive liquid metal / solid UO_2 systems, the validity and feasibility of the different existing models for calculating W in the metal /ox- ide systems are discussed. It can be shown that the models assuming that only metal atom-oxygen ion interactions existing at the interfaces are unable to explain the experimental results for W. More reasonable model should take into account both metal atom-oxygen ion and metal atom-oxide metal cation interactions, the proportion of the latter is balanced by the stoichiometry of the oxide. By applying the model recently set up by the authors for binary alloy / oxide systems, one can use the experimental and calculated values of θ and W for various metal / UO_2 systems to predict the influence of metallic additions on the contact angle and the work of adhesion of a given metal / UO_2 system.
