检索结果-内蒙古大学图书馆

A new format for the elastic scattering differential cross section covariance of charged particles

Annals of Nuclear Energy 2025年 222卷

作者： Han, Xu Liu, Jie Chen, Zhen-Peng Ye, Tao China Academy of Engineering Physics Beijing100193 China State Key Laboratory of Nuclear Physics and Technology Institute of Heavy Ion Physics School of Physics Peking University Beijing100871 China Department of Physics Tsinghua University Beijing100084 China Institute of Applied Physics and Computational Mathematics Beijing100094 China

For the elastic scattering of charged particles, there is no clear format in the ENDF-6 document to publish the covariance data of the differential cross sections. Since the covariance data is a function of both energy and angle, the publication of the raw data will make the data file extremely large and is difficult to be used in the nuclear data processing programs. In this paper, we proposed a new format for publishing this data. The angular distributions of correlation coefficients are fitted using a superposition equation and the fitting parameter values along with the standard deviation data are published, which can be used to reconstruct the covariance matrix. Based on the Generalized Reduced R-matrix theory, the RAC program (R-matrix analysis code) was employed to evaluate the experimental data of all nuclear reaction channels associated with the 7Be system. The 6Li(p, p)6Li reaction of the 7Be system were selected as an example for testing the proposed data format. The calculated results show that the amount of released data with the new format is only 1/10 of the original covariance raw data and the accuracy is reduced by only 5.21%, which indicates the proposed new format is effective and reliable. © 2025 Elsevier Ltd

关键词： Elastic scattering

来源：评论

学校读者我要写书评

暂无评论

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

引用

Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： Q.K.Liu L.Deng Q.Wang X.Zhang F.Q.Meng Y.P.Wang Y.Q.Gao H.B.Cai S.P.Zhu Graduate School China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230026China Shanghai Institute of Laser Plasma Shanghai 201800China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China School of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BSRS)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BSRS evolution driven by broadband lasers.

关键词： scattering kinetic simplified

来源：评论

学校读者我要写书评

暂无评论

A First Collision Source Method Using Spherical Harmonics Method for Arbitrary Shape and Order Finite Element Mesh

SSRN

引用

SSRN 2023年

作者： Dai, Tao Xu, Longfei Li, Baiwen Shen, Huayun Shi, Xueming Institute of Applied Physics and Computational Mathematics Haidian District Beijing100094 China

The discrete ordinates (SN ) method is a highly effective and accurate angular discretization method for the neutron transport equation, but suffers from the inherent ray effect in low-scattering regions. The first collision source (FCS) method employing the methods without ray effect to obtain the uncollided flux is a common ray effect mitigation technique. In this paper, a novel FCS method using the spherical harmonics (PN ) method to calculate the uncollided flux is proposed. The PN for the first collision source method (PN-FCS) possesses distinctive advantages in several aspects: (1) it can be applied in the problem containing reflective boundary conditions, (2) it uses the discontinuous Galerkin method to perform spatial discretization, and thus can be easily applied in arbitrary shape and order finite element meshes, (3) it can be effectively calculated in parallel on distributed meshes, (4) the accuracy and computational cost can be flexibly adjusted. Besides, the filter technique is adopted to improve the performance of the PN method in stream-dominated regions. The PN -FCS method has been implemented in two- and three-dimensional neutron transport code and tested by various testing problems. Numerical results show that the PN -FCS method can effectively mitigate the ray effect. © 2023, The Authors. All rights reserved.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

REMARKS ON THE CAUCHY PROBLEM OF THE ONE-DIMENSIONAL VISCOUS RADIATIVE AND REACTIVE GAS

引用

Acta Mathematica Scientia 2020年第4期40卷 1020-1034页

作者： Yongkai LIAO Institute of Applied Physics and Computational Mathematics Beijing 100088China

This paper is concerned with the large-time behavior of solutions to the Cauchy problem of a one-dimensional viscous radiative and reactive *** on the elaborate energy estimates,we develop a new approach to derive the upper bound of the absolute temperature by avoiding the use of auxiliary functions Z(t)and W(t)introduced by Liao and Zhao[*** Equations,2018,265(5):2076-2120].Our results also improve upon the results obtained in Liao and Zhao[*** Equations,2018,265(5):2076-2120].

关键词： large-time behavior viscous radiative and reactive gas Cauchy problem large initial data

来源：评论

学校读者我要写书评

暂无评论

Electronic processes in collisions between nitrogen ions and hydrogen atoms

引用

Physical Review A 2024年第6期110卷 062820-062820页

作者： C. C. Jia Y. Y. Qi J. J. Niu Y. Wu J. G. Wang A. Dubois N. Sisourat J. W. Gao Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Sorbonne Université CNRS UMR 7614 Laboratoire de Chimie Physique-Matière et Rayonnement 75005 Paris France College of Mechanical Engineering Jiaxing University Jiaxing 314001 China School of Physics Hangzhou Normal University Hangzhou 311121 China

In order to interpret and predict the behavior and properties of fusion plasma, accurate cross sections for electronic processes in collisions between plasma impurities and atomic hydrogen are required. In this work, we investigate the electron capture (or charge exchange), target excitation, and ionization processes occurring in collision of N4+ with atomic hydrogen in a broad energy domain ranging from 0.06 to 225 keV/u. We consider N4+ ground-state N4+(2s) and also N4+(2p) since the impurities in the edge plasma environment may be excited due to collisions with electrons and ions or atoms. Total and partial cross sections in both spin-averaged and spin-resolved cases are calculated using a two-active-electron semiclassical asymptotic-state close-coupling approach. For electron capture cross sections the present results show overall good agreement with available experimental data for both total and partial cross sections, and the origins of observed discrepancies are discussed. Furthermore, we provide data for target excitation and ionization processes, which are essential to improve our understanding of this relevant collision system.

关键词： Ground state

来源：评论

学校读者我要写书评

暂无评论

-Robust Error Analysis of Two Nonuniform Schemes for Subdiffusion Equations with Variable-Order Derivatives

引用

Journal of Scientific Computing 2023年第2期97卷 1-21页

作者： Huang, Chaobao An, Na Chen, Hu Yu, Xijun School of Statistics and Mathematics Shandong University of Finance and Economics Jinan China School of Mathematics and Statistics Shandong Normal University Jinan China School of Mathematical Sciences Ocean University of China Qingdao China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing China

In this paper, we will consider the variable-order subdiffusion initial-boundary value problem with weakly singular solutions. By using the nonuniform L1 scheme and nonuniform Alikhanov scheme in time, two efficient numerical methods (which we call L1 FEM and Alikhanov FEM) are developed, where the finite element method is used in space. Firstly, an improved error analysis is given for the L1 FEM of Huang and Chen (Appl Math Lett 139:108559, 2023), and the derived error bounds remain valid as $$\alpha (t^*)\rightarrow 1^-$$ for $$0\le t^*\le T$$ . To obtain the $$\alpha $$ -robust optimal convergent analysis for Alikhanov FEM, the truncation error of the Alikhanov scheme for the variable-order Caputo derivative and an $$\alpha $$ -robust bound on the complementary discrete kernels $$\mathbb {P}_j^{(n)}$$ are presented. Combining these two results with an $$\alpha $$ -robust discrete fractional Gronwall inequality, the optimal convergent results in $$L^\infty (L^2)$$ norm and $$L^\infty (H^1)$$ norm are derived. Furthermore, by adopting a simple postprocessing technique of the numerical solution, a higher convergence order in space is obtained. Finally, a numerical example is presented to verify the optimal theoretical convergent result.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Kinetic model and Vlasov simulation verification of two-ion decay instability

引用

Physical Review E 2023年第2期108卷 025206-025206页

作者： D. J. Liu Qing Wang X. M. Li S. T. Zhang R. J. Cheng X. X. Li S. Y. Lv Z. M. Huang Qiang Wang Z. J. Liu L. H. Cao C. Y. Zheng Institute of Applied Physics and Computational Mathematics Beijing 100094 China HEDPS Center for Applied Physics and Technology and State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing 100871 China HEDPS Center for Applied Physics and Technology and College of Engineering Peking University Beijing 100871 China

A kinetic theory is developed to describe the longitudinal decay of two-ion decay (TID): The pump ion-acoustic wave (IAW) decays into two daughter IAWs with a longer wavelength. The instability growth rate and threshold are given by the theory. Both the simulations of full kinetic Vlasov and hybrid Vlasov (kinetic ions and Boltzmann electrons) are employed to verify the theory and have a high quantitative agreement with the theory for 8≤ZTe/Ti≤15, where Z is the ion charge number and Ti(Te) is the ion (electron) temperature. The kinetic model developed here solves a long-standing problem that the simple fluid theory underestimates growth rate by a factor of 2∼3. Also, a reasonable explanation is given to the typical characteristics of TID that the dependence curves of subharmonic growth rate γ and wave number k.

关键词： High-energy-density plasmas Inertial confinement fusion Ion-acoustic instability Ion-acoustic waves Laser-plasma interactions Nonlinear phenomena in plasmas Plasma instabilities Plasma turbulence Stimulated Brillouin & Raman scattering in plasmas

来源：评论

学校读者我要写书评

暂无评论

Enumeration and Representation Theory of Spin Space Groups

引用

Physical Review X 2024年第3期14卷 031038页

作者： Xiaobing Chen Jun Ren Yanzhou Zhu Yutong Yu Ao Zhang Pengfei Liu Jiayu Li Yuntian Liu Caiheng Li Qihang Liu Department of Physics and Shenzhen Institute for Quantum Science and Engineering National Center for Applied Mathematics Shenzhen and Department of Mathematics Guangdong Provincial Key Laboratory of Computational Science and Material Design Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices

Fundamental physical properties, such as phase transitions, electronic structures, and spin excitations, in all magnetic ordered materials, were ultimately believed to rely on the symmetry theory of magnetic space groups. Recently, it has come to light that a more comprehensive group, known as the spin space group (SSG), which combines separate spin and spatial operations, is necessary to fully characterize the geometry and underlying properties of magnetic ordered materials. However, the basic theory of SSG has seldom been developed. In this work, we present a systematic study of the enumeration and the representation theory of the SSG. Starting from the 230 crystallographic space groups and finite translation groups with a maximum order of eight, we establish an extensive collection of over 100 000 SSGs under a four-index nomenclature as well as international notation. We then identify inequivalent SSGs specifically applicable to collinear, coplanar, and noncoplanar magnetic configurations. To facilitate the identification of the SSG, we develop an online program that can determine the SSG symmetries of any magnetic ordered crystal. Moreover, we derive the irreducible corepresentations of the little group in momentum space within the SSG framework. Finally, we illustrate the SSG symmetries and physical effects beyond the framework of magnetic space groups through several representative material examples, including a candidate altermagnet RuO2, spiral spin polarization in the coplanar antiferromagnet CeAuAl3, and geometric Hall effect in the noncoplanar antiferromagnet CoNb3S6. Our work advances the field of group theory in describing magnetic ordered materials, opening up avenues for deeper comprehension and further exploration of emergent phenomena in magnetic materials.

关键词： Electronic structure Magnetic order Spin texture Noncollinear magnets Density functional theory Group theory

来源：评论

学校读者我要写书评

暂无评论

Isomerization in highly excited states of triply charged carbon dioxide ions produced by intense laser fields

引用

Physical Review A 2024年第5期110卷 053110-053110页

作者： Ruichao Dong Ahai Chen Jinze Feng Shuai Zhang Wenbin Jiang Xiaoqing Hu Yong Wu Jianguo Wang Xincheng Wang Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201210 China University of Chinese Academy of Sciences Beijing 100049 China Center for Transformative Science and School of Physical Science and Technology ShanghaiTech University Shanghai 201210 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China

It is commonly accepted that the isomerization process primarily occurs in lowly charged molecular states, while highly charged states typically favor a direct fragmentation pathway through Coulomb repulsion. In the current experiment with an intense 800-nm laser field, a three-body isomerization pathway leading to intermediate O22+ formation and subsequent dissociation is observed in highly excited states of CO23+. It is confirmed by the calculated potential energy curves that CO23+ molecular ions in highly excited states with a linear geometry could transition through conical intersections into low-lying states with a bond angle around 70∘ (e.g., 62A1→12A1, 102B1→12B1), finally leading to oxygen molecule ions formation via isomerization. The present findings demonstrate that isomerization-induced change in molecular structures is a universal and nonnegligible phenomenon, even in triply charged molecular ions, providing insights into the photoinduced ultrafast processes in Earth's primitive atmosphere and benefit the understanding of CO2-dominated planetary atmospheres.

关键词： Photodissociation

来源：评论

学校读者我要写书评

暂无评论

Equation of state for boron nitride along the principal Hugoniot to 16 Mbar

引用

Matter and Radiation at Extremes 2024年第5期9卷 77-86页

作者： Huan Zhang Yutong Yang Weimin Yang Zanyang Guan Xiaoxi Duan Mengsheng Yang Yonggang Liu Jingxiang Shen Katarzyna Batani Diluka Singappuli Ke Lan Yongsheng Li Wenyi Huo Hao Liu Yulong Li Dong Yang Sanwei Li Zhebin Wang Jiamin Yang Zongqing Zhao Weiyan Zhang Liang Sun Wei Kang Dimitri Batani National Key Laboratory of Plasma Physics Laser Fusion Research CenterChina Academy of Engineering PhysicsMianyang 621900China HEDPS Center for Applied Physics and Technologyand College of PhysicsPeking UniversityBeijing 100871China HEDPS Center for Applied Physics and Technologyand School of EngineeringPeking UniversityBeijing 100871China Institute of Plasma Physics and Laser Microfusion Hery 2301-497 WarszawaPoland Universitéde Bordeaux CNRSCEACELIA(Centre Lasers Intenses et Applications)UMR 5107F-33405 TalenceFrance Institute of Applied Physics and Computational Mathematics Beijing 100094China

The thermodynamic properties of boron nitride under extreme pressures and temperatures are of great interest and importance for materials science and inertial confinement fusion physics,but they are poorly understood owing to the challenges of performing experiments and realizing ab initio ***,we report the first shock Hugoniot data on hexagonal boron nitride at pressures of 5–16 Mbar,using hohlraum-driven shock waves at the SGIII-p laser facility in *** density functional theory molecular dynamics calculations closely match experimental data,validating the equations of state for modeling the shock response of boron nitride and filling a crucial gap in the knowledge of boron nitride properties in the region of multi-Mbar pressures and eV *** results presented here provide fundamental insights into boron nitride under the extreme conditions relevant to inertial confinement fusion,hydrogen–boron fusion,and high-energy-density physics.

关键词： boron Hugoniot extreme

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：