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Machine learning-based interatomic potential for simulating irradiation damage mechanisms in ZrC

Journal of Materials Science & Technology 2026年 242卷 75-91页

作者： Chang-jie Ding Xiao-yang Wang Xiang-yan Li Wei-shu Yang Xiao-lin Li Yan-ge Zhang Yi-chun Xu Chang-song Liu Xuebang Wu Institute of Solid State Physics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei 230031 China University of Science and Technology of China Hefei 230026 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Molecular dynamics simulation of irradiation damage is critical for understanding microstructural evolution and defect formation in zirconium carbide (ZrC). However, the absence of a suitable interatomic potential remains a challenge. Here, we develop a precise deep-neural-network based machine learning interatomic potential tailored for investigating irradiation damage in ZrC. Our model accurately reproduces the energetics and kinetics of native point defects, thermodynamics properties, surface energies, and generalized stacking fault energies. We further explore collision cascades spanning a range of primary knock-on atom energies (from 1 keV to 40 keV), types (C and Zr), and directions (〈100〉, 〈010〉, and 〈111〉) at 300 K. The results reveal carbon interstitial atoms and vacancies as the dominant point defects, consistent with first-principles calculations, with the notable formation of carbon-rich clusters within collision cascades. These carbon-rich defect clusters, resembling “black-dot” structures in experimental observations, emerge directly in collision cascades and remain thermodynamically stable at low temperatures due to the low mobility of Zr interstitial atoms. In contrast to the absence of dislocation loops in the collision cascade simulations, our results suggest a thermally-driven mechanism for the formation and transformation of 1/3 〈111〉 and 1/2 〈110〉 dislocation loops. This work enriches our understanding of the irradiation damage mechanism in ZrC and other carbide ceramics.

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Plasticity and melting characteristics of metal Al with Ti-cluster under shock loading

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Chinese physics B 2021年第7期30卷 200-208页

作者： Dong-Lin Luan Ya-Bin Wang Guo-Meng Li Lei Yuan Jun Chen School of Mechatronic Engineering Beijing Institute of TechnologyBeijing 100081China System Engineering Research Institute Beijing 100094China Beijing Special Vehicle Research Institute Beijing 100072China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Center for Applied Physics and Technology Peking UniversityBeijing 100871China

Impurity agglomeration has a significant influence on shock response of metal *** this paper,the mechanism of Ti-clusters in metal Al under shock loading is investigated by non-equilibrium molecular dynamics *** results show that the Ti-cluster has obvious effects on the dislocation initiation and melting of bulk ***,the Ti clusters induces the strain concentrate and leads the dislocations to be initiated from the interface of Ti ***,dislocation distribution from the Ti-cluster model results in a formation of a grid-like structure,while the dislocation density is reduced compared with that from the perfect Al ***,the critical shock velocity of dislocation from the Ti-cluster model is lower than from perfect Al ***,it is also found that the temperature near the interface of Ti-cluster is100 K–150 K higher than in the other areas,which means that Ti-cluster interface melts earlier than the bulk area.

关键词： molecular dynamics impurity cluster dislocation shock loading

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NUMERICAL SIMULATION of REACTOR NEUTRON NOISE BASED on DISCRETE ORDINATE FINITE ELEMENT METHOD 29

NUMERICAL SIMULATION of REACTOR NEUTRON NOISE BASED on DISCR...

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2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Yuan, Baoxin Luo, Xin Zeng, Herong Huang, Huan Zheng, Jie Yang, Wankui Zhang, Songbao Zhong, Bin Wei, Junxia Ying, Yangjun China Academy of Engineering Physics Insititute of Nuclear Physics and Chemistry Mianyang China Institute of Applied Physics and Computational Mathematics Beijing China

ISBN: (纸本)9780791886366

At present, the technology of reactor neutron noise is developing rapidly, which can not only be used to measure some intrinsic parameters of the reactor core, but also be used for core fault diagnosis. The theoretical solution of reactor neutron noise is of great significance for providing information on the directivity of core faults, and its analytical solution is extremely difficult or even impossible. Therefore, it is necessary to study the numerical simulation method of reactor neutron noise. In this work, the governing equations of the neutron noise problem are firstly established based on the discrete ordinate finite element theory, the equations take the reactor steady-state parameters and the core disturbance cross-section as input parameters. Secondly, the frequency domain solver FrequencyDomain-SNSolver of neutron noise is developed, which is capable of acquiring steady-state parameters, reading disturbance cross-section and calculating neutron noise. Finally, for a calculation case of an experimental reactor core, the neutron noise distribution and spectrum under perturbation are obtained by using the developed FrequencyDomain-SNSolver. This work can provide some reference and technical support for related research. © 2022 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Finite element method

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THE GLOBAL COMBINED QUASI-NEUTRAL AND ZERO-ELECTRON-MASS LIMIT OF NON-ISENTROPIC EULER-POISSON SYSTEMS

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Acta Mathematica Scientia 2022年第4期42卷 1666-1680页

作者： Yongfu YANG Qiangchang JU Shuang ZHOU College of Science Hohai UniversityNanjing 211100China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Chengxi Junior High School Suzhou215128 China

We consider a non-isentropic Euler-Poisson system with two small parameters arising in the modeling of unmagnetized plasmas and *** the basis of the energy estimates and the compactness theorem,the uniform global existence of the solutions and the combined quasi-neutral and zero-electron-mass limit of the system are proved when the initial data are close to the constant equilibrium *** particular,the limit is rigorously justified as the two parameters tend to zero independently.

关键词： Non-isentropic Euler-Poisson system global smooth solutions uniform energy estimates global convergence compactness

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Gamma ray multiplicity of a^(240)Pu solid sphere simulated by JMCT

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Nuclear Science and Techniques 2022年第5期33卷 8-15页

作者： Huan-Huan Ding Fan Gao Chang-Bing Lu Rui Li Chen-Guang Li Zhao-Hong Mo Dun-Fu Shi Ming Su De-Shan Zhao Mao-Bing Shuai Zhong-Hua Xiong Bin-Yuan Xia Yun Bai Institute of Materials China Academy of Engineering PhysicsMianyang 621908China The 93147th Unit of PLA Mianyang 621000China CAEP Software Center for High Performance Numerical Simulation Beijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Determining the mass of plutonium metal is an important research objective in the field of nuclear material accounting and *** on the 3D neutron and photon transport code JMCT(Jointed Monte Carlo Transport),the gamma ray multiplicity of ^(240)Pu was simulated in this study,and the average number of gamma rays leaking from ^(240)Pu solid spheres with different masses was also *** simulation results show that there is a oneto-one correspondence between the average number of gamma rays and the mass of ^(240)Pu solid spheres in the range of 0.50–3.00 *** result provides a basis for using the average number of gamma rays to account for the mass of ^(240)Pu.

关键词： ^(240)Pu JMCT Gammaraymultiplicity Solid sphere mass Surface-to-volumeratio

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Existence of Global Attractor for Weakly Damped FDS Nonlinear Wave Equations

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Annals of applied mathematics 2024年第4期40卷 333-345页

作者： Boling Guo Ying Zhang Institute of Applied Physics and Computational Mathematics Beijing 100088China The Graduate School of China Academy of Engineering Physics Beijing 100088China

The paper investigates the well-posedness of global solutions and the existence of global attractors for weakly damped FDS nonlinear wave *** establishes the well-posedness of weak solutions using Galerkin approximation and a priori ***,a dynamical system is constructed based on the well-posedness of the *** existence of a bounded absorbing set for the equations and the smooth properties of the operator semigroup are presented,leading to the existence of a global attractor.

关键词： Global attractors a priori estimate FDS nonlinear wave equations

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Correlations in interacting electron liquids: Many-body statistics and hyperuniformity

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Physical Review B 2024年第10期110卷 104201页

作者： Haina Wang Rhine Samajdar Salvatore Torquato Department of Chemistry Department of Physics Princeton Center for Theoretical Science Princeton Materials Institute Program in Applied and Computational Mathematics

Disordered hyperuniform many-body systems are exotic states of matter with novel optical, transport, and mechanical properties. These systems are characterized by an anomalous suppression of large-scale density fluctuations compared to ordinary liquids. The structure factor of disordered hyperuniform systems often obeys the scaling relation S(k)∼Bkα with B,α>0 in the limit k→0. Ground states of d-dimensional free fermionic gases, which are fundamental models for many metals and semiconductors, are key examples of quantum disordered hyperuniform states with important connections to random matrix theory. However, the effects of electron-electron interactions as well as the polarization of the electron liquid on hyperuniformity have not been explored thus far. In this paper, we systematically address these questions by deriving the analytical small-k behaviors (and, associated, α and B) of the total and spin-resolved structure factors of quasi-one-dimensional, two-dimensional, and three-dimensional electron liquids for varying polarizations and interaction parameters. We validate that these equilibrium disordered ground states are hyperuniform, as dictated by the fluctuation-compressibility relation. Interestingly, free fermions, partially polarized interacting fermions, and fully polarized interacting fermions are characterized by different values of the small-k scaling exponent α and coefficient B. In particular, partially polarized fermionic liquids exhibit a unique form of multihyperuniformity, in which the net configuration exhibits a stronger form of hyperuniformity (i.e., larger α) than each individual spin component. The detailed theoretical analysis of such small-k behaviors enables the construction of corresponding equilibrium classical systems under effective one- and two-body interactions that mimic the pair statistics of quantum electron liquids. Our paper thus reveals that highly unusual hyperuniform and multihyperuniform states can be achieved in simple

关键词： Electronic structure Quantum many-body systems Two-dimensional electron gas

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A Partial RKDG Method for Solving the 2D Ideal MHD Equations Written in Semi-Lagrangian Formulation on Moving Meshes with Exactly Divergence-Free Magnetic Field

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Advances in applied mathematics and Mechanics 2023年第4期15卷 932-963页

作者： Shijun Zou Xijun Yu Zihuan Dai Fang Qing Xiaolong Zhao School of Mathematical Sciences Peking UniversityBeijing 100871China Institute of Applied Physics and Computational Mathematics Beijing 100088China Department of Mathematics Southern University of Science and TechnologyShenzhenGuangdong 518055China School of Mathematics and Statistics Zhengzhou UniversityZhengzhouHenan 450001China

A partial Runge-Kutta Discontinuous Galerkin(RKDG)method which preserves the exactly divergence-free property of the magnetic field is proposed in this paper to solve the two-dimensional ideal compressible magnetohydrodynamics(MHD)equations written in semi-Lagrangian formulation on moving quadrilateral *** this method,the fluid part of the ideal MHD equations along with zcomponent of the magnetic induction equation is discretized by the RKDG method as our previous paper[47].The numerical magnetic field in the remaining two directions(i.e.,x and y)are constructed by using the magnetic flux-freezing principle which is the integral form of the magnetic induction equation of the ideal *** the divergence of the magnetic field in 2D is independent of its z-direction component,an exactly divergence-free numerical magnetic field can be obtained by this *** propose a new nodal solver to improve the calculation accuracy of velocities of the moving meshes.A limiter is presented for the numerical solution of the fluid part of the MHD equations and it can avoid calculating the complex eigen-system of the MHD *** numerical examples are presented to demonstrate the accuracy,non-oscillatory property and preservation of the exactly divergence-free property of our method.

关键词： Ideal compressible MHD equations semi-Lagrangian formulation exactly divergence-free magnetic field Runge-Kutta discontinuous Galerkin method

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Compressive holographic sensing simplifies quantitative phase imaging

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Light(Science & Applications) 2023年第6期12卷 946-948页

作者： Jiawei Sun Juergen W.Czarske Competence Center for Biomedical Computational Laser Systems(BIOLAS) TU DresdenDresdenGermany Laboratory of Measurement and Sensor System Technique(MST) TU DresdenHelmholtzstrasse 1801069 DresdenGermany Cluster of Excellence Physics of Life TU DresdenDresdenGermany Institute of Applied Physics TU DresdenDresdenGermany

Quantitative phase imaging (QPI) has emerged as method for investigating biological specimen and technical objects. However, conventional methods often suffer from shortcomings in image quality, such as the twin image artifact. A novel computational framework for QPI is presented with high quality inline holographic imaging from a single intensity image. This paradigm shift is promising for advanced QPI of cells and tissues.

关键词： holographic phase shortcomings

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A multi-material diagnosis method based on high-energy proton radiography

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Matter and Radiation at Extremes 2023年第4期8卷 47-54页

作者： Feng Chen Haibo Xu Junhui Shi Xinge Li Na Zheng Zhejiang Lab Hangzhou 310000China Institute of Applied Physics and Computational Mathematics Beijing 100094China Graduate School of China Academy of Engineering Physics Beijing 100088China

Diagnosis of fluids is extremely significant at high temperatures and high *** an advanced imaging technique,high-energy proton radiography has great potential for application to the diagnosis of high-density *** high-energy proton radiography,an angular collimator can control the proton flux and thus enable material diagnosis and reconstruction of *** this paper,we propose a multimaterial diagnostic method using angular *** method is verified by reconstructing the density distribution from the proton flux obtained via theoretical calculations and numerical *** simulate a 20 GeV proton imaging system using the Geant4 software toolkit and obtain the characteristic parameters of single-material *** design several concentric spherical objects to verify the *** discuss its application to detonation *** results show that this method can determine the material and boundary information about each component of a multi-material ***,it can be used to diagnose a mixed material and reconstruct densities in a detonation.

关键词： density. method. method

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