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Chinese Physics B 2024年第9期33卷 433-442页

作者： Kaixuan Li Cheng Ning Ye Dong Chuang Xue institute of applied Physics and computational mathematics Beijing 100088China

For investigating efficiently the stagnation kinetic-process of Z-pinch,we develop a novel modified electrostatic implicit particle-in-cell algorithm in radial one-dimension for Z-pinch simulation in which a small-angle cumulative binary collision algorithm is *** our algorithm,the electric field in z-direction is solved by a parallel electrode-plate model,the azimuthal magnetic field is obtained by Ampere’s law,and the term for charged particle gyromotion is approximated by the cross product of the averaged velocity and magnetic *** simulation results of 2 MA deuterium plasma shell Zpinch,the mass-center implosion trajectory agrees generally with that obtained by one-dimensional MHD simulation,and the plasma current also closely aligns with the external *** phase space diagrams and radial-velocity probability distributions of ions and electrons are *** main kinetic characteristic of electron motion is thermal equilibrium and oscillation,which should be oscillated around the ions,while that of ion motion is implosion *** the region of stagnation radius,the radial-velocity probability distribution of ions transits from the non-equilibrium to equilibrium state with the current increasing,while of electrons is basically the equilibrium *** the initial ion density and current peak are not high enough,the ions may not reach their thermal equilibrium state through collisions even in its stagnation phase.

关键词： Z-pinch particle-in-cell ion heating charged particle collisions

INCOMPRESSIBLE LIMIT OF IDEAL MAGNETOHYDRODYNAMICS IN A DOMAIN WITH BOUNDARIES

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Acta Mathematica Scientia 2024年第4期44卷 1441-1465页

作者： Qiangchang JU Jiawei WANG institute of applied Physics and computational mathematics Beijing 100088China

We study the incompressible limit of classical solutions to compressible ideal magneto-hydrodynamics in a domain with a flat *** boundary condition is characteristic and the initial data is *** first establish the uniform existence of classical solutions with respect to the Mach ***,we prove that the solutions converge to the solution of the incompressible MHD *** particular,we obtain a stronger convergence result by using the dispersion of acoustic waves in the half space.

关键词： incompressible limit ideal MHD equations boundary condition general initial data

STABLE RECOVERY OF SPARSELY CORRUPTED SIGNALS THROUGH JUSTICE PURSUIT DE-NOISING

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Journal of computational mathematics 2024年第1期42卷 271-288页

作者： Ningning Li Wengu Chen Huanmin Ge institute of applied Physics and computational mathematics Beijing 100088China Beijing Sport University Beijing 100084China

This paper considers a corrupted compressed sensing problem and is devoted to recover signals that are approximately sparse in some general dictionary but corrupted by a combination of interference having a sparse representation in a second general dictionary and measurement *** provide new restricted isometry property(RIP)analysis to achieve stable recovery of sparsely corrupted signals through Justice Pursuit De-Noising(JPDN)with an additional *** main tool is to adapt a crucial sparse decomposition technique to the analysis of the Justice Pursuit *** proposed RIP condition improves the existing representative *** simulations are provided to verify the reliability of the JPDN model.

关键词： Justice Pursuit De-Noising Restricted isometry property Corrupted compressed sensing Signal recovery

Ionization Potential Depression Model for Warm/Hot and Dense Plasmas

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Chinese Physics Letters 2024年第8期41卷 45-57页

作者： Chensheng Wu Fuyang Zhou Jun Yan Xiang Gao Yong Wu Chunhua Zeng Jianguo Wang institute of applied Physics and computational mathematics Beijing 100088China Faculty of Science Kunming University of Science and TechnologyKunming 650500China

For warm/hot and dense plasmas(WDPs),ionization potential depression(IPD)plays a crucial role in determining its ionization balance and understanding the resultant microscopic plasma properties.A sophisticated and unified IPD model is necessary to resolve those existing discrepancies between theoretical and experimental ***,the applicability of those widely used IPD models nowadays is limited,especially for the nonlocal thermodynamic equilibrium(non-LTE)dense plasma produced by short-pulse *** this work,we propose an IPD model that considers inelastic atomic processes,in which three-body recombination and collision ionization processes are found to play a crucial role in determining the electron distribution and IPD for a *** IPD model is validated by reproducing latest experimental results of Al plasmas with a wide-range condition of 70 eV–700 eV temperature and 0.2–3 times solid density,as well as a typical non-LTE system of hollow Al *** is demonstrated that the present IPD model has a significant temperature dependence due to the consideration of the inelastic collision *** a lower computational cost and wider application range of plasma conditions,the proposed model is expected to provide a promising tool to study the ionization balance and the atomic processes,as well as the related radiation and particle transports properties of the WDP.

关键词： properties. collision determining

Reflection behavior of insensitive explosive detonation propagating around a cylinder

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Acta Mechanica Sinica 2024年第7期40卷 55-65页

作者： Zixuan Zhang Yuan Wang Xiaomian Hu Haitao Chen institute of applied Physics and computational mathematics Beijing 100094China Graduate School of China Academy of Engineering Physics Beijing 100088China

Insensitive explosive detonation has wide applications in compressing and driving inert materials,and thereby the interaction between detonation and inert materials has received more *** this paper,a two-dimensional numerical simulation based on the Euler multiphase flow framework is used to investigate the reflection behavior of the insensitive explosive detonation propagating around a *** results show that there is a critical incident angle,defined as transition angle for detonation propagating around the cylinder,below which the regular reflection(RR)on the cylinder surface is *** the incident angle is greater than the transition angle,RR changes to Mach *** transition angle is larger than that obtained by polar curve theory and the change of incident angle is used to interpret above *** addition,the influence of cylindrical radius and detonation reaction zone width on the reflection behavior is *** the cylindrical radius increases,the height of Mach stem increases while the transition angle decreases and gradually approaches the value in pole curve *** Neumann reflection is observed when the reaction zone width is relatively *** is because the energy release rate in the reaction zone is high for small reaction zone width,resulting in the formation of a series of compression waves near the cylindrical interface.

关键词： Insensitive explosive detonation Cylindrical inert material Reflection behavior

Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction

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Matter and Radiation at Extremes 2024年第5期9卷 109-114页

作者： Jing Yang Xinxin Wang Liang Xu Qiannan Wang Yi Sun Jiangtao Li Lin Zhang Yinghua Li Yuying Yu Pei Wang Qiang Wu Jianbo Hu Laboratory for Shock Wave and Detonation Physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100094China

We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray *** experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction ***,we observe a deviation from the widely accepted isentropic release assumption,with the temperature of the fragments being found to be more than 100 K higher than expected,owing to the release of plastic work during dynamic *** findings are further verified through extensive large-scale molecular dynamics simulations,in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids,leading to an increase in *** findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.

关键词： dynamic release diffraction

Semi-hydro-equivalent design and performance extrapolation between 100 kJ-scale and NIF-scale indirect drive implosion

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Matter and Radiation at Extremes 2024年第1期9卷 25-34页

作者： Huasen Zhang Dongguo Kang Changshu Wu Liang Hao Hao Shen Shiyang Zou Shaoping Zhu Yongkun Ding Laboratory of computational Physics Institute of Applied Physics and Computational MathematicsBeijing 10088China institute of applied Physics and computational mathematics Beijing 10088China

Extrapolation of implosion performance between different laser energy scales is investigated for indirect drive through a semi-hydroequivalent *** radiation transport is non-hydro-equivalent,the peak radiation temperature of the hohlraum and the ablation velocity of the capsule ablator are not scale-invariant when the sizes of the hohlraum and the capsule are scale-varied.A semi-hydro-equivalent design method that keeps the implosion velocity V_(i),adiabat α_(F),and P_(L)/R_(hc)^(2) (where P_(L) is the laser power and R_(hc) is the hohlraum and capsule scale length)scale-invariant,is proposed to create hydrodynamically similar *** semi-hydro-equivalent design and the scaled implosion performance are investigated for the 100 kJ Laser Facility(100 kJ-scale)and the National Ignition Facility(NIF-scale)with about 2 MJ laser *** is found that the one-dimensional implosion performance is approximately hydro-equivalent when V_(i) and α_(F) are kept the *** to the non-hydro-equivalent radiation transport,the yield-over-clean without α-particle heating(YOC_(noα))is slightly lower at 100 kJ-scale than at NIF-scale for the same scaled radiation asymmetry or the same initial perturbation of the hydrodynamic *** overall scaled two-dimensional implosion performance is slightly lower at 100 *** general Lawson criterion factor scales asχ_(noα) ^(2D)∼S^(1.06±0.04)(where S is the scale-variation factor)for the semi-hydro-equivalent implosion design with a moderate YOC_(noα).Our study indicates that χ_(noα)≈0.379 is the minimum requirement for the 100 kJ-scale implosion to demonstrate the ability to achieve marginal ignition at NIF-scale.

关键词： performance transport slightly

Research on Multi-Scale Feature Fusion Network Algorithm Based on Brain Tumor Medical Image Classification

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Computers, Materials & Continua 2024年第6期79卷 5313-5333页

作者： Yuting Zhou Xuemei Yang Junping Yin Shiqi Liu Graduate School China Academy of Engineering PhysicsBeijing100000China Department of computational mathematics Beijing Institute of Applied Physics and Computational MathematicsBeijing100000China National Key Laboratory of computational Physics Beijing100088China Shanghai Zhangjiang institute of mathematics Shanghai201203China

Gliomas have the highest mortality rate of all brain *** classifying the glioma risk period can help doctors make reasonable treatment plans and improve patients’survival *** paper proposes a hierarchical multi-scale attention feature fusion medical image classification network(HMAC-Net),which effectively combines global features and local *** network framework consists of three parallel layers:The global feature extraction layer,the local feature extraction layer,and the multi-scale feature fusion layer.A linear sparse attention mechanism is designed in the global feature extraction layer to reduce information *** the local feature extraction layer,a bilateral local attention mechanism is introduced to improve the extraction of relevant information between adjacent *** the multi-scale feature fusion layer,a channel fusion block combining convolutional attention mechanism and residual inverse multi-layer perceptron is proposed to prevent gradient disappearance and network degradation and improve feature representation *** double-branch iterative multi-scale classification block is used to improve the classification *** the brain glioma risk grading dataset,the results of the ablation experiment and comparison experiment show that the proposed HMAC-Net has the best performance in both qualitative analysis of heat maps and quantitative analysis of evaluation *** the dataset of skin cancer classification,the generalization experiment results show that the proposed HMAC-Net has a good generalization effect.

关键词： Medical image classification feature fusion transformer

Driver at 10 MJ and 1 shot/30 min for inertial confinement fusion at high gain:Efficient,compact,low-cost,low laser-plasma instabilities,beam color selectable from 2ω/3ω/4ω,applicable to multiple laser fusion schemes

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Matter and Radiation at Extremes 2024年第4期9卷 4-7页

作者：隋展蓝可 Shanghai institute of Laser Plasma China Academy of Engineering PhysicsShanghai 201800China instituteof applied Physics and computational mathematics Beijing 100094China

The achievement of ignition at the National Ignition Facility(NIF)has prompted a global wave of further research on inertial fusion energy(IFE).However,IFE requires a target gain G of 30-100,and it is hard to achieve fusion at such high gain with the energy,configuration,and technical approach of the ***,we present a conceptual design for a next-generation laser driver that is applicable to multiple laser fusion schemes and provides 10 MJ,2-3 PW at 3ω(or 2ω,in which case the energy and power can be higher),and one shot per 30 min,with the aim of achieving G>*** is also efficient,compact,and low in cost,and it has low susceptibility to laser-plasma instabilities.

关键词： applicable compact instabilities

Strong-coupling superconductivity with Tc above 70 K in Be-decorated monolayer T-graphene

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 99-105页

作者： Liu Yang Peng-Fei Liu Hao-Dong Liu Ya-Ping Li Na Jiao Hong-Yan Lu Bao-Tian Wang Ping Zhang School of Physics and physical Engineering Qufu Normal UniversityQufu 273165China institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China institute of applied Physics and computational mathematics Beijing 100088China

Using first-principles calculations,we predict a new type of two-dimensional(2D)beryllium(Be)-decorated T-graphene named BeC_(2),where Be atoms are inserted into C–C bonds linking the carbon tetrarings of *** band structure shows that BeC_(2)is metallic,thus,the possible phonon-mediated superconductivity is explored based on the Eliashberg *** calculated electron-phonon coupling(EPC)constantλis up to 4.07,and the corresponding superconducting critical temperature(Tc)is 72.1 K,approaching the liquid nitrogen *** reason for the high Tc is the strong *** it is proved to be an anisotropic single-gap superconductor by analyzing the superconducting gap?kof BeC_(2).The electronic susceptibility calculation shows strong nesting effect in BeC_(2).Since rare 2D superconductors show such a strong EPC constantλwhich originates from the coupling between electrons in C-pzorbital and in-plane vibrations of Be and C atoms,the predicted BeC_(2)provides a new platform for investigating strong EPC 2D superconductor.

关键词： two-dimensional carbon-based superconductor electron-phonon coupling strong coupling high superconducting critical temperature