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Mechanical responses and crystal plasticity model of CoCrNi medium-entropy alloy under ramp wave compression

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Matter and Radiation at Extremes 2024年第5期9卷 93-108页

作者： Jinlei Dong Xuping Zhang Guiji Wang Xianqian Wu Binqiang Luo Xuemiao Chen Fuli Tan Jianheng Zhao Chengwei Sun institute of {1. physics China Academy of Engineering PhysicsMianyang 621999China institute of Mechanics Chinese Academy of SciencesBeijing 100190China institute of Applied Electronics China Academy of Engineering PhysicsMianyang 621999China

It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys(MEAs)under high strain rates and *** this study,the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression(RWC)with a strain rate of 1.5 s^(−1..The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced *** characterizations reveal that grain refinement and abundant micromechanisms,including dislocation slip,stacking faults,nanotwin network,and Lomer–Cottrell locks,collectively contribute to its excellent performance during ***,dense deformation twins and shear bands intersect,forming a weave-like microstructure that can disperse deformation and enhance *** the basis of these observations,we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms,providing a relatively accurate quantitative description of the multiscale behavior under *** results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during *** research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA,positioning it as a promising material for use under extreme dynamic conditions.

关键词： deformation alloy microstructure

Benchmark experiment on slab^(238)U with D-T neutrons for validation of evaluated nuclear data

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Nuclear Science and Techniques 2024年第2期35卷 145-159页

作者： Yan-Yan Ding Yang-Bo Nie Yue Zhang Zhi-Jie Hu Qi Zhao Huan-Yu Zhang Kuo-Zhi Xu Shi-Yu Zhang Xin-Yi Pan Chang-Lin Lan Jie Ren Xi-Chao Ruan Key Laboratory of Nuclear Data China Institute of Atomic EnergyBeijing 102413China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China institute of {1. physics China Academy of Engineering PhysicsMianyang 62100China

A benchmark experiment on^(238)U slab samples was conducted using a deuterium-tritium neutron source at the China institute of Atomic *** leakage neutron spectra within energy levels of 0.8-1. MeV at 60°and 1.0°were measured using the time-of-flight *** samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3,6,and 9 *** leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of^(238)U evaluated neutron data from CENDL-3.2,ENDF/B-Ⅷ.0,JENDL-5.0,and *** on the comparison,the deficiencies and improvements in^(238)U evaluated nuclear data were *** results showed the following.(1.The calculated results for CENDL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60°and 1.0°.(2)The calculated results of CENDL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 1.0°.(3)The calculated results for CENDL-3.2 significantly overestimated the measurements in the 3-8.5 MeV energy interval at 60°and 1.0°.(4)The calculated results with JENDL-5.0 were generally consistent with the measurement results.

关键词： Leakage neutron spectra Uranium D-T neutron source Evaluated nuclear data

First-principles study of structural and electronic properties of multiferroic oxide Mn_(3)TeO_(6) under high pressure

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Chinese physics B 2024年第7期33卷 448-454页

作者：潘小龙王豪柳雷陈向荣耿华运 College of physics Sichuan UniversityChengdu 610065China National Key Laboratory of Shock Wave and Detonation physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyang 621900China HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking UniversityBeijing 100871China

Mn_(3)TeO_(6)(MTO) has been experimentally found to adopt a P2_(1./In structure under high pressure,which exhibits a significantly smaller band gap compared to the atmospheric R3 *** this study,we systematically investigate the magnetism,structural phase transition,and electronic properties of MTO under high pressure through first-principles *** R3 and P2_(1./n phases of MTO are antiferromagnetic at zero *** R3 phase transforms to the P2_(1./n phase at 7.5 8 GPa,accompanied by a considerable volume collapse of about 6.47%.Employing the accurate method that combines DFT+U/and GW,the calculated band gap of R3 phase at zero pressure is very close to the experimental values,while that of the P2_(1./n phase is significantly *** main reason for this difference is that the experimental study incorrectly used the Kubelka-Munk plot for the indirect band gap to obtain the band gap of the P2_(1./n phase instead of the Kubelka-Munk plot for the direct band ***,our study reveals that the transition from the R3 phase to the P2_(1./n phase is accompanied by a slight reduction in the band gap.

关键词： magnetism phase transition band gap high pressure

Enhanced soft magnetic properties of SiO_(2)-coated FeSiCr magnetic powder cores by particle size effect

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Chinese physics B 2024年第10期33卷 405-412页

作者： Mingyue Ge Likang Xiao Xiaoru Liu Lin Pan Zhangyang Zhou Jianghe Lan Zhengwei Xiong Jichuan Wu Zhipeng Gao Joint Laboratory for Extreme Conditions Matter Properties School of Mathematics and PhysicsSouthwest University of Science and TechnologyMianyang 621010China Southwest institute of Applied Magnetism Mianyang 621010China institute of {1. physics China Academy of Engineering PhysicsMianyang 621900China Sichuan Civil-military Integration institute Mianyang 621010China

It has been known that metal FeSiCr powders with large average particle sizes have been typically employed to prepare magnetic powder cores(SMCs),with few studies reported on the influence of magnetic properties for original powders with various average particle sizes less than 1.*** this work,SiO_(2)-coated FeSiCr SMCs with different small particle sizes were synthesized using the sol-gel *** contribution of SiO_(2)coating amount and voids to the soft magnetic properties was *** mechanism was revealed such that smaller particle sizes with less voids could be beneficial for reducing core loss in the *** optimizing the core structure,permeability and magnetic loss of 26 and 262 kW/cm^(3)at 1.0 kHz and 50 mT were achieved at a particle size of 4.8m and ethyl orthosilicate addition of 0.1.mL/*** best DC stacking performance,reaching 87%,was observed at an ethyl orthosilicate addition rate of 0.25 mL/g under 1.0 *** to other soft magnetic composites(SMCs),the FeSiCr/SiO_(2)SMCs exhibit significantly reduced magnetic *** further reduces the magnetic loss of the powder core,providing a new strategy for applications of SMCs at high frequencies.

关键词： FeSiCr SiO_(2) size effect magnetic properties DC superposition

Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

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Defence Technology（防务技术） 2024年第5期35卷 151-167页

作者： Chenyang Wu Xiaowei Chen Qiguang He State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyHaidian DistrictBeijing 100081China institute of {1. physics China Academy of Engineering PhysicsMianyang 621900SichuanChina

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective *** this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud *** damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear *** main impact stage lasts a short time and is the basis of the rear plate *** the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear *** further analyze the damage mechanism and damage distribution characteristics of the rear plate in ***,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris *** on the relationship,the features of typical damage areas are identified by the localized fine *** the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

关键词： Damage of rear plate Debris cloud Secondary impact Hypervelocity yaw impact FE-SPH adaptive method

The dry-hot feedback between soil moisture and atmosphere and the accelerated global warming

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Science China Earth Sciences 2024年第3期67卷 890-891页

作者： Tianjun ZHOU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Greenhouse gas (GHG) emissions have been increasing due to human activities since the Industrial Revolution, resulting in continuous warming of the global climate system and significant drought over a large parts of global land, both have shown a non-linear growth trend in recent decades(Berg et al., 201.;Zhou et al., 201.;IPCC, 2021..

关键词： warming moisture drought

Calculation of ship motions in steep waves with restoring and Froude-Krylov forces on an adaptive panel mesh with Gauss and analytic integration methods

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Journal of Hydrodynamics 2024年第2期36卷 275-289页

作者： Malwin Wermbter Moustafa Abdel-Maksoud institute for {1. Dynamics and Ship Theory Hamburg University of TechnologyHamburgGermany

The impulse response method is a frequently used method to calculate ship seakeeping *** this paper,the restoring and Froude-Krylov calculation is conducted with constant evaluation of panel pressures as well as Gauss quadrature and an analytical *** applied panel grid is coarsened by an adaptive algorithm which is based on a normal vector *** comparison of methods is based on grid convergence studies which are followed by a verification of forces with computational fluid dynamics(CFD)results on the fixed duisburg test case in *** with experimental results in head,oblique and following waves show that all integration methods are *** exact integration is numerically sensitive in some *** quadrature is highly accurate;however,the additional effort is not beneficial since the geometrical accuracy has-stronger influence on the force amplitudes than the integration *** grid coarsening reduces the simulation time and is accurate up to a level,where the panel length comes close the *** added resistance at the investigated Froude number of 0.05 shows higher uncertainty levels,this applies to the results of both the numerical methods and model tests.

关键词： Ship hydrodynamics seakeeping impulse response method added resistance wave loads

A comprehensive diagnostic system of ultra-thin liquid sheet targets

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High Power Laser Science and Engineering 2024年第3期12卷 41-50页

作者： Ziyang Peng Zhengxuan Cao Xuan Liu Yinren Shou Jiarui Zhao Shiyou Chen Ying Gao Pengjie Wang Zhusong Mei Zhuo Pan Defeng Kong Shirui Xu Zhipeng Liu Yulan Liang Tianqi Xu Tan Song Xun Chen Qingfan Wu Yujia Zhang Zihao Zhang Xueqin Yan Wenjun Ma State Key Laboratory of Nuclear physics and Technology School of PhysicsPeking UniversityBeijingChina National Key Laboratory of Shock Wave and Detonation physics Institute of Fluid PhysicsChina Academy of Engineering PhysicsMianyangChina Center for Relativistic Laser Science Institute for Basic ScienceGwangjuRepublic of Korea institute of Radiation {1. Helmholtz-Zentrum Dresden RossendorfDresdenGermany Beijing Laser Acceleration Innovation Center BeijingChina institute of Guangdong Laser Plasma Technology GuangzhouChina

To meet the demands of laser-ion acceleration at a high repetition rate,we have developed a comprehensive diagnostic system for real-time and in situ monitoring of liquid sheet targets(LSTs).The spatially resolved rapid characterizations of an LST’s thickness,flatness,tilt angle and position are fulfilled by different subsystems with high *** the help of the diagnostic system,we reveal the dependence of thickness distribution on collision parameters and report the 238-nm liquid sheet generated by the collision of two liquid *** methods for the flatness and tilt angle of LSTs have also been provided,which are essential for applications of laser-driven ion acceleration and others.

关键词： diagnostics laser-ion acceleration liquid sheet targets

The Persistence and Zonal Scale of Atmospheric Dipolar Modes

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Advances in Atmospheric Sciences 2024年第3期41卷 478-492页

作者： Jie SONG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP)Chinese Academy of SciencesBeijing 100029China

This study investigates the relationship between the persistence and the zonal scale of atmospheric dipolar modes(DMs). Results from the daily data of ERA5 and the long-term output of an idealized atmospheric model show that the atmospheric DMs with a broader(narrower) zonal scale dipolar structure possess a longer(shorter) persistence. A detailed vorticity budget analysis indicates that the persistence of a hemispheric-scale DM(1.1.DM) and a regional or sectoral DM(1.8 DM) in the model both largely rely on the persistence of the nonlinear eddy forcing. Linear terms can indirectly reduce the persistence of the anomalous nonlinear eddy forcing in a 1.8 DM by modifying the baroclinicity via the arousal of anomalous vertical motions. Therefore, the atmospheric DMs with a broader(narrower) zonal scale possess a longer(shorter) persistence because the effects of the linear terms are less(more) pronounced when the atmospheric DMs have better(worse) zonal symmetry. Further analyses show that the positive eddy feedback effect is weak or even absent in a 1.8DM and the high-frequency eddy forcing acts more like a concomitant phenomenon rather than a leading driving factor for a 1.8 DM. Thus, the hemispheric-scale DM and the regional or sectoral DMs are different, not only in their persistence but also in their dynamics.

关键词： NAM NAO eddy feedback persistence linear term