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Application of the asynchronous advantage actor–critic machine learning algorithm to real-time accelerator tuning

Nuclear Science and Techniques 2019年第10期30卷 133-141页

作者： Yun Zou Qing-Zi Xing Bai-Chuan Wang Shu-Xin Zheng Cheng Cheng Zhong-Ming Wang Xue-Wu Wang Key Laboratory of Particle and Radiation Imaging(Tsinghua University) Ministry of EducationBeijing 100084China Laboratory for Advanced Radiation Sources and Application Tsinghua UniversityBeijing 100084China Department of Engineering Physics Tsinghua UniversityBeijing 100084China State Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear TechnologyXian 710000China

This paper describes a real-time beam tuning method with an improved asynchronous advantage actor–critic(A3C)algorithm for accelerator *** operating parameters of devices are usually inconsistent with the predictions of physical designs because of errors in mechanical matching and ***,parameter optimization methods such as pointwise scanning,evolutionary algorithms(EAs),and robust conjugate direction search are widely used in beam tuning to compensate for this ***,it is difficult for them to deal with a large number of discrete local *** A3C algorithm,which has been applied in the automated control field,provides an approach for improving multi-dimensional *** A3C algorithm is introduced and improved for the real-time beam tuning code for *** in which optimization is achieved by using pointwise scanning,the genetic algorithm(one kind of EAs),and the A3C-algorithm are conducted and compared to optimize the currents of four steering magnets and two solenoids in the low-energy beam transport section(LEBT)of the Xi’an Proton Application *** currents are determined when the highest transmission of a radio frequency quadrupole(RFQ)accelerator downstream of the LEBT is *** optimal work points of the tuned accelerator were obtained with currents of 0 A,0 A,0 A,and 0.1 A,for the four steering magnets,and 107 A and 96 A for the two ***,the highest transmission of the RFQ was 91.2%.Meanwhile,the lower time required for the optimization with the A3C algorithm was successfully *** with the A3C algorithm consumed 42%and 78%less time than pointwise scanning with random initialization and pre-trained initialization of weights,respectively.

关键词： Real-time beam tuning Parameter optimization Asynchronous advantage actor–critic algorithm Low-energy beam transport

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Giant electro-optic effect in chiral topological semimetal RhSi

arXiv

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arXiv 2021年

作者： Li, Zhi Gao, Yuewen Gu, Yu Zhang, Shengli Iitaka, Toshiaki Liu, W.M. MIIT key Laboratory of Advanced Display Materials and Devices Ministry of Industry and Information Technology Institute of optoelectronics & Nanomaterials Nanjing University of Science and Technology Nanjing210094 China Discrete Event Simulation Research Team RIKEN Center for Computational Science 2-1 Hirosawa Saitama Wako351-0198 Japan Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China

We studied the linear electro-optic effect of chiral topological semimetal RhSi which is characterized by high-fold chiral fermions separated in energy space. We identify that the general second order conductivity (formula presented) includes a real symmetric component and an imaginary antisymmetric component, which are from the inter-band shift and intra-band injection current with frequency ω, respectively. The (formula presented) is significantly enhanced by the high electron velocity and nontrivial band topology of chiral fermion, and modifies the phase velocity of light wave. We also predict that the electro-optic coefficient (formula presented) of chiral crystal RhSi is about 7000 pm/V at photon energy 0.01 eV and 1.1 eV, which is about 200 times that of widely used LiNbO3 crystal. The giant electro-optic coefficient renders a relatively low half-wave voltage in order of hundreds volt, and demonstrates potential application as electro-optic crystals for the wavelength in the second telecom window of optical fiber communications. Copyright © 2021, The Authors. All rights reserved.

关键词： Optical fibers

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A hyperelastic model for hollow fiber-reinforced composites at finite deformation

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Mechanics of Materials 2025年 207卷

作者： Wang, Jialin Chen, Liangbin Hao, Meirong Chen, Yang Guo, Zaoyang Liang, Jun School of Science Harbin Institute of Technology Guangdong Shenzhen518055 China School of Civil Aviation Northwestern Polytechnical University Shaanxi Xi'an710072 China Research & Development Institute of Northwestern Polytechnical University in Shenzhen Northwestern Polytechnical University Guangdong Shenzhen518063 China Division of Atmosphere and Aerospace Information Technology Beijing Institute of Technology Guangdong Zhuhai519088 China Institute of Advanced Structure Technology Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology Beijing100081 China State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing100081 China

This study introduces a micromechanics-based constitutive model to describe the effective hyperelastic behaviors of hollow fiber-reinforced composites under finite deformation. The multiplicative decomposition approach is employed to decompose a general deformation into three fundamental deformations: isochoric uniaxial deformation along the fiber direction, equi-biaxial deformation on the transverse plane, and pure shear deformation. Based on this multiplicative decomposition, the free energy density function of the composites is thus additively decomposed into the three corresponding components. Subsequently, the effective free energy density functions of the composite for triaxial deformation (composed of the isochoric uniaxial deformation along the fiber direction and equi-biaxial deformation on the transverse plane), along-fiber shear, and transverse shear are derived using a cylindrical composite element model. The total free energy density function of the composite is then obtained by summing the contributions of these decomposed deformations. To validate the proposed model, finite element simulations based on representative volume elements are conducted. The effects of fiber volume fraction, fiber/matrix stiffness ratio, and wall thickness of hollow fiber on the effective mechanical behaviors of the composites are explored. The theoretical predictions show excellent agreement with numerical results for all considered cases, demonstrating that the proposed model reliably predicts the effective mechanical response of hollow fiber-reinforced composites under finite deformation. Finally, to further validate the prediction accuracy and computational efficiency of the developed model, it is applied to the structural analysis of a cantilever beam, with results compared to those obtained using the FE2 method. This comparative analysis demonstrates again the accuracy and efficiency of the proposed approach in practical structural analysis. © 2025

关键词： Fiber reinforced plastics

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Multi-parameter mechanistic study on the influence of vaporizer fuel atomization characteristics on combustor ignition and flame propagation processes

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Energy 2025年 330卷

作者： Sun, Bolun Liu, Xin Xiong, Shihang Sun, Bonan Song, Wenyan Le, Jialing Li, Jianping Wang, Li Li, Yahui Zhu, Xuejian School of Power and Energy Northwestern Polytechnical University Xi'an710129 China Hubei Key Laboratory of Advanced Aerospace Propulsion Technology System Design Institute of Hubei Aerospace Technology Academy Wuhan430040 China AECC Hunan Aviation Powerplant Research Institute Zhuzhou412002 China Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi'an710119 China

To address light-round failure during ignition in the vaporizer combustor of micro and small gas turbine engine (MS-GTE), this study investigates the effects of multiple parameters on atomization characteristics using PDPA and shadowgraphy. The results indicate that the inward contraction of spray distribution promotes flame propagation within a single vaporizer but hinders it between adjacent vaporizers. Increasing the exit diameter improves turbulent shear and fuel mist distribution while reducing SMD at the spray boundary. Circumferential holes at the exit induce localized wall-attached vortices that expand spray coverage outward while reducing SMD and mitigating inward spray contraction. Higher air pressure differential promotes continuous-phase breakup and spray expansion. Elevated wall temperatures enhance atomization, though this improvement tends to saturate at higher levels. Furthermore, ignition and light-round experiments were conducted using a three-sector combustor with high-speed imaging to validate the atomization findings. Vaporizers with larger exit diameters improve atomization uniformity and fuel mist dispersion, enabling shorter ignition and light-round timing at lower fuel-air ratios. The circumferential holes expand fuel mist dispersion, filling fuel vacuum regions between adjacent vaporizers and significantly enhancing ignition and light-round performance. The dominant mechanisms in each phase determine how various vaporizer configurations influence ignition and light-round behavior. © 2025

关键词： Gas turbines

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Erratum: “simulation of chiral motion of excitation within the ground-state manifolds of neutral atoms” [APL Quantum 1, 036109 (2024)]

APL Quantum

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APL Quantum 2024年第3期1卷

作者： Hao-Yuan Tang Xiao-Xuan Li Jia-Bin You Xiao-Qiang Shao Center for Quantum Sciences and School of Physics Northeast Normal University Changchun 130024 China Sino-European Institute of Aviation Engineering Civil Aviation University of China Tianjin 300300 China Institute of High Performance Computing A*STAR (Agency for Science Technology and Research) 1 Fusionopolis Way Connexis Singapore 138632 Center for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education Northeast Normal University Changchun 130024 China

In the original version of this article initially published,1 there were still some typographical errors that should be corrected.

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simulation of chiral motion of excitation within the ground-state manifolds of neutral atoms

APL Quantum

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APL Quantum 2024年第3期1卷

Laser-induced gauge fields in neutral atoms serve as a means of mimicking the effects of a magnetic field, providing researchers with a platform to explore behaviors analogous to those observed in condensed matter systems under real magnetic fields. Here, we propose a method to generate chiral motion in atomic excitations within the neutral atomic ground-state manifolds. This is achieved through the application of polychromatic driving fields coupled to the ground–Rydberg transition, along with unconventional Rydberg pumping. The scheme offers the advantage of arbitrary adjustment of the effective magnetic flux by setting the relative phases between different external laser fields. In addition, the effective interaction strength between the atomic ground states can be maintained at 10 kHz, surpassing the capabilities of the previous approach utilizing Floquet modulation. Notably, the proposed method can be readily extended to implement a hexagonal neutral atom lattice, serving as the fundamental unit in realizing the Haldane model.

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Dflow, a Python framework for constructing cloud-native AI-for-Science workflows

arXiv

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arXiv 2024年

作者： Liu, Xinzijian Han, Yanbo Li, Zhuoyuan Fan, Jiahao Zhang, Chengqian Zeng, Jinzhe Shan, Yifan Yuan, Yannan Xu, Wei-Hong Liu, Yun-Pei Zhang, Yuzhi Wen, Tongqi York, Darrin M. Zhong, Zhicheng Zheng, Hang Cheng, Jun Zhang, Linfeng Wang, Han DP Technology Beijing100080 China Institute of Molecular Science and Applied Chemistry School of Chemistry Xi'an Jiaotong University Xi'An710049 China Department of Mechanical Engineering The University of Hong Kong Hong Kong School of Physics Peking University Beijing100871 China AI for Science Institute Beijing100080 China HEDPS CAPT College of Engineering Peking University Beijing100871 China Laboratory for Biomolecular Simulation Research Center for Integrative Proteomics Research Department of Chemistry and Chemical Biology Rutgers University PiscatawayNJ08854-8087 United States Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo315201 China IKKEM Xiamen361005 China State Key Laboratory of Physical Chemistry of Solid Surface Collaborative Innovation Center of Chemistry for Energy Materials College of Chemistry and Chemical Engineering Xiamen University Xiamen361005 China Department of Physics University of Science and Technology of China Hefei230026 China Suzhou Institute for Advanced Research University of Science and Technology of China Suzhou215123 China Institute of Artificial Intelligence Xiamen University Xiamen361005 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100094 China

In the AI-for-science era, scientific computing scenarios such as concurrent learning and high-throughput computing demand a new generation of infrastructure that supports scalable computing resources and automated workflow management on both cloud and high-performance supercomputers. Here we introduce Dflow, an open-source Python toolkit designed for scientists to construct workflows with simple programming interfaces. It enables complex process control and task scheduling across a distributed, heterogeneous infrastructure, leveraging containers and Kubernetes for flexibility. Dflow is highly observable and can scale to thousands of concurrent nodes per workflow, enhancing the efficiency of complex scientific computing tasks. The basic unit in Dflow, known as an Operation (OP), is reusable and independent of the underlying infrastructure or context. Dozens of workflow projects have been developed based on Dflow, spanning a wide range of projects. We anticipate that the reusability of Dflow and its components will encourage more scientists to publish their workflows and OP components. These components, in turn, can be adapted and reused in various contexts, fostering greater collaboration and innovation in the scientific community. Copyright © 2024, The Authors. All rights reserved.

关键词： Reusability

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The Effects of Parameter Variations on the Torque Control of Induction Motor

The Effects of Parameter Variations on the Torque Control of...

引用

Conference on Vehicle Control and Intelligence (CVCI)

作者： Feixiang Zhao Jianwei Zhang Dongmei Wu Guoqing Liu Wensong Lang Pinglai Wang Automotive Research Institute China National Heavy Duty Truck Group Co.ltd. Jinan China State Key Laboratory of Automotive Simulation and Control Jilin University Changchun China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan China

ISBN: (数字)9781728184975

ISBN: (纸本)9781728184982

By analyzing the principle and method of the direct vector control torque control method for induction motor, an analysis method of the influence of motor parameter changes on the accuracy of motor electromagnetic torque control under steady-state conditions is proposed, and the application of four common flux observations is derived. In direct vector control, the error function of the electromagnetic torque is estimated. The influence of the change of induction motor parameters on the torque control accuracy is theoretically analyzed, and the simulation is verified by Simulink. The simulation proves that the method can correctly analyze the torque control accuracy under the condition of induction motor vector control without complicated calculations.

关键词： Resistance Inductance Torque Induction motors Torque control Stators Observers

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Omitted variable bias in single-pollutant epidemiological models for estimating long-term health effects of ambient fine particulate matter and ozone

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Journal of Hazardous Materials 2025年 494卷 138590页

作者： Xue, Tao Deng, Jianyu Ni, Xueqiu Kang, Ning Tong, Mingkun Li, Pengfei School of Public Health Peking University Health Science Centre Beijing100191 China Advanced Institute of Information Technology Peking University Hangzhou311215 China State Key Joint Laboratory of Environment Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing100871 China Institute of Medical Technology Peking University Health Science Centre Beijing100191 China

Long-term exposure to PM2.5 and O3 is linked to various adverse health outcomes. However, many epidemiological studies on their health effects use single-pollutant models, leading to omitted variable bias (OVB). The percent bias, based on the classical OVB formula, depends on the PM2.5-O3 correlation and unobservable true effects. Data were sourced from two recent meta-analyses of the log-linear link between all-cause mortality and per-unit exposure to PM2.5 or O3. We then developed a new meta-regression method to correct biases, and its performance was verified through simulation. The OVB for PM2.5 or O3 can vary greatly from positive to negative across different spatial scales (like country, sub-national region, or city). By applying this method to 24 individual estimates, we found that a 10 μg/m³ increase in PM2.5 was linked to a 7.4 % increase in all-cause mortality risk, while O3’s association with all-cause mortality was not significant, which implies that PM2.5 must be considered in epidemiological analyses to obtain reliable effect estimates for O3. Our findings offer novel methodologies for the systematic assessment of the health effects of multiple pollutants. This contribution holds significant potential in fortifying health intervention strategies and minimizing the health risks posed by air pollution to the public. © 2025 Elsevier B.V.

关键词： Air quality

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Giant anomalous Nernst effect in noncollinear antiferromagnetic Mn-based antiperovskite nitrides

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Physical Review Materials 2020年第2期4卷 024408-024408页

作者： Xiaodong Zhou Jan-Philipp Hanke Wanxiang Feng Stefan Blügel Yuriy Mokrousov Yugui Yao Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement Ministry of Education School of Physics Beijing Institute of Technology Beijing 100081 China Peter Grünberg Institut and Institute for Advanced Simulation Forschungszentrum Jülich and JARA 52425 Jülich Germany Institute of Physics Johannes Gutenberg University Mainz 55099 Mainz Germany

The anomalous Nernst effect (ANE)—the generation of a transverse electric voltage by a longitudinal heat current in conducting ferromagnets or antiferromagnets—is an appealing approach for thermoelectric power generation in spin caloritronics. The ANE in antiferromagnets is particularly convenient for the fabrication of highly efficient and densely integrated thermopiles as lateral configurations of thermoelectric modules increase the coverage of heat source without suffering from the stray fields that are intrinsic to ferromagnets. In this work, using first-principles calculations together with a group theory analysis, we systematically investigate the spin-order-dependent ANE in noncollinear antiferromagnetic Mn-based antiperovskite nitrides Mn3XN(X=Ga, Zn, Ag, and Ni). The ANE in Mn3XN is forbidden by symmetry in the R1 phase but amounts to its maximum value in the R3 phase. Among all Mn3XN compounds, Mn3NiN presents the most significant anomalous Nernst conductivity of 1.80AK−1m−1 at 200 K, which can be further enhanced if strain, electric, or magnetic fields are applied. The ANE in Mn3NiN, being one order of magnitude larger than that in the famous Mn3Sn, is the largest one discovered in antiferromagnets so far. The giant ANE in Mn3NiN originates from the sharp slope of the anomalous Hall conductivity at the Fermi energy, which can be understood well from the Mott relation. Our findings provide a host material for realizing antiferromagnetic spin caloritronics that promises exciting applications in energy conversion and information processing.

关键词： Spintronics Thermoelectric effects Antiferromagnets First-principles calculations

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