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Analysis of Optic and Electric Combines Measurement Uncertainty Under Strong Impact Loading 1

International Conference on Optoelectronics and Measurement, ICOM 2019

作者： Zheng, Miao Wei, Lan Institute of Applied Physics and Computational Mathematics Beijing100094 China

ISBN: (数字)9789813341104

ISBN: (纸本)9789813341098

When the metal material undergoes a series of physical processes such as strong impact loading, unloading, reverse stretching and reloading in the complex system, the layer fracture of the material is easy to occur in the reverse stretching stage. In order to study the movement behavior and law of metal material under strong impact loading, the free surface particle velocity and the movement process of the sample surface with time were obtained by the verify of DISAR and electric probe measurement technique. In this paper, the uncertainty sources of two kinds of test systems are analyzed, and the test error ranges are given respectively. In the two dimensional Lagrange hydrodynamics program, the layer fracture processing function considering void growth, polymerization and collapse effect is added to carry out numerical simulation research. The simulation results show that the layer fracture occurs in the process of loading and unloading, and the experimental data are in good agreement with the simulation results. The width of the platform and the takeoff height of the speed curve are basically the same, and the relative error is not more than 10%. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Fracture

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Simulation of cylinder SGEMP radiated by X-ray 4

Simulation of cylinder SGEMP radiated by X-ray

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4th International Conference on Radiation Effects of Electronic Devices, ICREED 2021

作者： Sun, Huifang Zhang, Lingyu Yang, Wenyuan Institute of Applied Physics and Computational Mathematics Beijing100094 China

ISBN: (纸本)9781665441681

The whole 3D simulation of SGEMP from X-ray to electromagnetic field environment is realized by developing 3D PIC code with compiling MC function modules in it, so that photoelectrons of arbitrary energy, angular, spatial and time distributions which calculated by transport code JMCT could be transformed into the initial current source used in PIC simulation directly. The simulation results are analyzed preliminarily. It is obtained that the emitted current is 0.11 A while the electric field could get 100 kV/m and magnetic field is over 1.6×10-6 T when the blackbody X-ray of temperature 1 keV and emitted fluence 1 J/cm2 perpendicularly irradiates the side of cylindrical object with material of A1 and height of 2.0 cm, radius of 1.0 cm. © 2021 IEEE

关键词： Electromagnetic fields

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Long-lived oscillations of metastable states in neutral atom systems

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Physical Review B 2024年第15期110卷 155114页

作者： Siva Darbha Milan Kornjača Fangli Liu Jan Balewski Mark R. Hirsbrunner Pedro L. S. Lopes Sheng-Tao Wang Roel Van Beeumen Katherine Klymko Daan Camps Applied Mathematics and Computational Research Division 1284 Soldiers Field Road Boston Massachusetts 02135 USA Department of Physics and Institute for Condensed Matter Theory

Metastable states arise in a range of quantum systems and can be observed in various dynamical scenarios, including decay, bubble nucleation, and long-lived oscillations. The phenomenology of metastable states has been examined in quantum many-body systems, notably in one-dimensional (1D) ferromagnetic Ising spin systems and superfluids. In this paper, we study long-lived oscillations of metastable and ground states in 1D antiferromagnetic neutral atom chains with long-range Rydberg interactions. We use a staggered local detuning field to achieve confinement. Using theoretical and numerical models, we identify novel spectral signatures of quasiparticle oscillations distinct to antiferromagnetic neutral atom systems and interpret them using a classical energy model of short-range meson repulsion. Finally, we evaluate the experimental accessibility of our proposed setup on current neutral-atom platforms and discuss experimental feasibility and constraints.

关键词： Antiferromagnetism Nonequilibrium statistical mechanics Quantum quench Quantum simulation Rydberg gases Rydberg atoms & molecules Exact diagonalization

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Hard constraint learning approaches with trainable influence functions for evolutionary equations

arXiv

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arXiv 2025年

作者： Zhang, Yushi Su, Shuai Wang, Yong Yao, Yanzhong Institute of Applied Physics and Computational Mathematics Beijing100088 China Graduate School of China Academy of Engineering Physics Beijing100088 China National Key Laboratory of Computational Physics Beijing100088 China School of Mathematics Statistics and Mechanics Beijing University of Technology Beijing100124 China

This paper develops a novel deep learning approach for solving evolutionary equations, which integrates sequential learning strategies with an enhanced hard constraint strategy featuring trainable parameters, addressing the low computational accuracy of standard physics-Informed Neural Networks (PINNs) in large temporal domains. Sequential learning strategies divide a large temporal domain into multiple subintervals and solve them one by one in a chronological order, which naturally respects the principle of causality and improves the stability of the PINN solution. The improved hard constraint strategy strictly ensures the continuity and smoothness of the PINN solution at time interval nodes, and at the same time passes the information from the previous interval to the next interval, which avoids the incorrect/trivial solution at the position far from the initial time. Furthermore, by investigating the requirements of different types of equations on hard constraints, we design a novel influence function with trainable parameters for hard constraints, which provides theoretical and technical support for the effective implementations of hard constraint strategies, and significantly improves the universality and computational accuracy of our method. In addition, an adaptive time-domain partitioning algorithm is proposed, which plays an important role in the application of the proposed method as well as in the improvement of computational efficiency and accuracy. Numerical experiments verify the performance of the method. The data and code accompanying this paper are available at https://***/zhizhi4452/HCS. Copyright © 2025, The Authors. All rights reserved.

关键词： Deep learning

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Probing H2 Double Ionization with Bicircular Laser Fields

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Physical Review Letters 2024年第14期132卷 143201-143201页

作者： Zhenning Guo Zhihe Zhang Yongkai Deng Jiguo Wang Difa Ye Jie Liu Yunquan Liu State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University Beijing 100871 China Center for Applied Physics and Technology HEDPS Peking University Beijing 100871 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Graduate School China Academy of Engineering Physics Beijing 100193 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China

We present a kinematically complete study on strong-field double ionization of H2 molecules in two-color bicircular laser fields. The releasing times of electrons and protons are recorded with the double-hand attoclock. We observe the relative emission angles of two electrons oscillate with the kinetic energy release of protons, indicating the internal concerted four-body fragmentation. Using a three-dimensional molecular semiclassical ensemble model, we have disentangled the attosecond correlated electron emission in H2 double ionization. This work reveals the strong electron-nuclear coupling in the molecular bond breaking and may open up a new approach to experimentally accessing the intramolecular electron and bond dynamics with bicircular fields.

关键词： Molecular dissociation Multiphoton or tunneling ionization & excitation Photodissociation Photoemission Ultrafast phenomena

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Numerical Simulation of Proppant Transport in Hydraulic Fractures of Conglomerate Reservoirs Based on Multi-phase Particle-in-Cell Method 12th

Numerical Simulation of Proppant Transport in Hydraulic Frac...

引用

12th International Field Exploration and Development Conference, IFEDC 2022

作者： Wen, Zhi-Cheng Zhang, Lie-Hui Tang, Hui-Ying Zeng, Jun-Sheng Zhang, Jing Wang, Ying-Wei Zhao, Yu-Long State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Chengdu China Institute of Applied Physics and Computational Mathematics Beijing China Research Institute of Exploration and Development PetroChina Xinjiang Oilfield Company Karamy China

ISBN: (纸本)9789819919635

The gravel particles affect the propagation of hydraulic fractures in conglomerate reservoirs. A hydraulic fracture can bypass or penetrate to propagate along a gravel particle, making the fracture geometry complex. Both the complexity of fracture geometry and presence of gravel particles have an important influence on the proppant transport and the fracture conductivity. By properly representing the grave particles, a two-dimensional multiphase particle-in-cell (MP-PIC) method was used to study the effects of grave particles and fracturing fluid viscosity on the transport behavior and placement characteristic of proppants in a hydraulic fracture of conglomerate reservoirs. The result indicates that the presence of grave particles exerts a complicated dynamic effect on proppants and significantly affects the horizontal transport and vertical settling of proppants. Proppants may be difficult to reach the specific region near the grave particles. Increasing the fracturing fluid viscosity can effectively improve proppant transport and placement. The presented paper first uses the MP-PIC method to carried out a numerical simulation study on proppant transport in a hydraulic fracture of conglomerate reservoirs and can provide theoretical guidance for the hydraulic fracturing of conglomerate reservoirs. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

关键词： Proppants

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基于SO(3)群几何精确Kirchhoff梁理论的细长梁动力学

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Acta Mechanica Sinica 2024年第4期40卷 212-225页

作者：安志朋王斌侯云森刘铖 MOE Key Laboratory of Dynamics and Control of Flight Vehicle School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China CAEP Software Center for High Performance Numerical Simulation Beijing100088China Institute of Applied Physics and Computational Mathematics Beijing100088China

本研究旨在开发一种高效的细长梁单元,精确描述细长柔性结构的大变形和大旋转,在现有细长梁单元研究的基础上,提出一种基于SO(3)群活动标架的二阶几何精确Kirchhoff梁单元(GEKBF),用于细长梁的动力学研究.首先,在此标架中推导出运动学... 详细信息

本研究旨在开发一种高效的细长梁单元,精确描述细长柔性结构的大变形和大旋转,在现有细长梁单元研究的基础上,提出一种基于SO(3)群活动标架的二阶几何精确Kirchhoff梁单元(GEKBF),用于细长梁的动力学研究.首先,在此标架中推导出运动学描述和几何、本构和动态平衡方程及其线性化.然后,引入相对扭转角的二阶插值函数,以提高单元的收敛性,通过选择合适的标架来开发旋转矢量参数化.它可以显著减少由刚体旋转引起的几何非线性,并提高描述当前标架下单元旋转公式的计算效率.此外,考虑了参考标架的影响,并使用空间平行移动而非时间平行移动,简化了弹性力和雅可比矩阵的推导.使用李群广义α-方法求解李群上的半离散运动方程.最后,通过数值实例验证了GEKBF的准确性,包括静力学和动力学.

关键词：平行移动标架弹性力旋转矢量细长梁柔性结构半离散动态平衡

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Multi-Electron Transfer of Ar^(+) Colliding with Ne Atoms Based on a Time-Dependent Density-Functional Theory

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Chinese physics Letters 2021年第6期38卷 24-29页

作者： Shuai Qin Cong-Zhang Gao Wandong Yu Yi-Zhi Qu School of Optoelectronics University of Chinese Academy of SciencesBeijing 100049China Institute of Applied Physics and Computational Mathematics Beijing 100088China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China

The multi-electron capture and loss cross-sections of Ar^(+)-Ne collisions are calculated at absolute energies in the few-keV/*** calculations are performed using a novel inverse collision framework,in the context of a time-dependent density functional theory,combined with molecular *** extraction of the capture and loss probabilities is based on the particle-number projection technique,originating from nuclear physics,but validly extended to represent many-electron *** agreement between experimental and theoretical data is found,which clearly reveals the non-negligible post-collision decay of the projectile’s electrons,providing further evidence for the applicability of the approach to complex many-electron collision systems.

关键词： dynamics collision negligible

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A New Matrix Feature Selection Strategy in Machine Learning Models for Certain Krylov Solver Prediction

SSRN

引用

SSRN 2023年

作者： Sun, Hai-Bing Jing, Yan-Fei Xu, Xiao-Wen School of Mathematical Sciences Institute of Computational Science University of Electronic Science and Technology of China Sichuan Chengdu611731 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100088 China

Numerical simulation processes in scientific and engineering applications require efficient solution of large sparse linear systems, and variants of Krylov subspace solvers with various preconditioning techniques have been developed. However, it is time consuming for practitioners with trial and error to find a high-performance Krylov solver for a given linear system. Therefore, it is instructive to select a better solver intelligently among a solver set before applying it to solve a linear system. One promising direction of solver selection is to apply machine learning methods to construct a mapping from the matrix features to the candidate solvers. However, the computation of some matrix features is quite difficult. In this paper, we design a new selection strategy of matrix features to reduce computing cost, and then employ the selected features to construct a machine learning classifier to predict an appropriate solver for a given linear system. Numerical experiments on two attractive GMRES-type solvers for solving linear systems from the University of Florida Sparse Matrix Collection and Matrix Market verify the efficiency of our strategy, not only reducing the computing time of features and construction time of classifier, but also keeping more than 90\% prediction accuracy. © 2023, The Authors. All rights reserved.

关键词： Linear systems

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Oxidation, mutual diffusion and crack behaviors of high-throughput prepared CrAl coating on Zry-4 in steam at 1200 °C

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Corrosion Science 2025年 253卷

作者： Zhu, Chaowen Zhang, Weina Zeng, Song Li, Muhong Qi, Lin Chen, Chen Meng, Yan Zhang, Ke Shen, Huahai Zhou, Xiaosong Han, Xiaochun Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang621900 China Institute of Applied Physics and Computational Mathematics China Academy of Engineering Physics Beijing100084 China

The compositionally graded CrAl coating was deposited on Zry-4 substrates by high-throughput magnetron sputtering. The oxidation, mutual diffusion and crack behaviors of CrAl coating in steam at 1200 °C exhibited strongly dependence on the initial Al concentration (NAl0). As NAl0 increased, the surface oxide transformed from the single-layer Cr2O3 to the bi-layer Cr2O3/α-Al2O3, and subsequently to the single-layer α-Al2O3. The transition point from the internal to the external oxidation was determined as 18.0 at% Al. The dependence of the thickness of the surface oxide layer and interdiffusion layers (IDLs) on NAl0 was demonstrated. The theoretical model of interface diffusion based on the Fick's second law was proposed. The Al reservoir was directly affected by the inward diffusion of Al rather than the oxidation process until the Al content decreased to a critical level. The cracks were caused by the stress when the α-Al2O3 formed internally, while they were a consequence of the aggregation of pores when the α-Al2O3 formed externally. Cracks and pores accumulated the ingress of O and outward diffusion of Zr, resulting in the failure of the CrAl coating © 2025 Elsevier Ltd

关键词： Aluminum coatings

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