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arXiv 2024年

作者： Wei, Wenyin Hua, Jiankun Knieps, Alexander Liang, Yunfeng Institute of Plasma Physics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Forschungszentrum Jülich GmbH Institute of Fusion Energy and Nuclear Waste Management – Plasma Physics Jülich52425 Germany International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

This study extends the functional perturbation theory (FPT) of dynamical systems, which was initially developed for investigating the shifts of magnetic field line trajectories within the chaotic edge region of plasma when subjected to global perturbations. By contrast, invariant tori reside in the ordered regions of phase space. In magnetic confinement fusion (MCF) devices, these tori manifest as closed flux surfaces, with their nested structure governing radial transport and thus playing a critical role in confinement performance. Using the method of variation as a mathematical foundation, this Letter derives formulae that characterize the deformation of invariant tori under perturbation. These results provide new tools for targeted topology control in tokamak operations and for optimizing stellarator designs by enhancing predictive capability for flux surface *** Codes Primary: 37D10, Secondary: 34D10, 37N05, 37N10, 37M21, 37J40, 39A33, 39B52, 76W05, 78M30 Copyright © 2024, The Authors. All rights reserved.

关键词： Perturbation techniques

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On the shifts of stable and unstable manifolds of a hyperbolic cycle under perturbation

arXiv

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arXiv 2024年

作者： Wei, Wenyin Hua, Jiankun Knieps, Alexander Liang, Yunfeng Institute of Plasma Physics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Forschungszentrum Jülich GmbH Institut für Energie- und Klimaforschung - Plasmaphysik Jülich52425 Germany International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China

Stable and unstable manifolds, originating from hyperbolic cycles, fundamentally characterize the behaviour of dynamical systems in chaotic regions. This letter demonstrates that their shifts under perturbation, crucial for chaos control, are computable with minimal effort using functional derivatives by considering the entire system as an argument. The shifts of homoclinic and heteroclinic orbits, as the intersections of these manifolds, are readily calculated by analyzing the movements of the intersection *** Codes Primary: 37D10, Secondary: 39A33, 39B52, 76W05, 78M30 Copyright © 2024, The Authors. All rights reserved.

关键词： Dynamical systems

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A Novel Resonant Frequency Tracking Control for Linear Compressor Based on MRAS Method

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CES Transactions on Electrical Machines and Systems 2020年第3期4卷 227-236页

作者： Wei Xu Qizhe Wang Xiang Li Yi Liu Jianguo Zhu State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan430074China School of Electrical and Information Engineering University of SydneySydneyNSW 2006Australia

To optimize the efficiency of the linear compressor,its operating frequency must be controlled equal to the system resonant *** traditional resonant frequency tracking control algorithm relies on the steady state characteristics of the system,which suffers from slow convergence speed,low accuracy and slow system *** order to solve these problems,a novel resonant frequency tracking control for linear compressor based on model reference adaptive system(MRAS)is proposed in this paper,and the parameter adaptive rate is derived by the Popov's hyperstability theory,so that the system resonant frequency can be directly calculated through the parameter adaptive ***,the traditional algorithm needs to calculate the piston stroke signal by integrating the back-EMF,which has the problem of integral *** algorithm proposed in this paper only needs the velocity signal,and the accuracy of the velocity calculation can be ensured by utilizing the self-adaptive band-pass filter(SABPF),thereby greatly improving the accuracy of the resonance frequency *** results verify the effectiveness of the proposed algorithm.

关键词： linear compressor linear oscillating motor(LOM) resonant frequency tracking control model reference adaptive system(MRAS)

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Hybrid thin-film lithium niobate micro-ring acousto-optic modulator for microwave-to-optical conversion

arXiv

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arXiv 2024年

作者： Wan, Lei Huang, Jiying Wen, Meixun Li, Huan Zhou, Wenfeng Yang, Zhiqiang Chen, Yuping Liu, Huilong Zeng, Siqing Liu, Dong Yang, Shuixian Dai, Daoxin Li, Zhaohui School of Physics Ningxia University Yinchuan750021 China Department of Electronic Engineering College of Information Science and Technology Jinan University Guangzhou510632 China State Key Laboratory of Extreme Photonics and Instrumentation Center for Optical & Electromagnetic Research College of Optical Science and Engineering International Research Center for Advanced Photonics Zhejiang University Zijingang Campus Hangzhou310058 China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems Sun Yat-sen University Guangzhou510275 China Zhuhai519000 China

Highly efficient acousto-optic modulation plays a vital role in the microwave-to-optical conversion. Herein, we demonstrate a hybrid thin-film lithium niobate (TFLN) racetrack micro-ring acousto-optic modulator (AOM) implemented with low-loss chalcogenide (ChG) waveguide. By engineering the electrode configuration of the interdigital transducer, the double-arm micro-ring acousto-optic modulation is experimentally confirmed in nonsuspended ChG loaded TFLN waveguide platform. Varying the position of blue-detuned bias point, the half-wave-voltage-length product VπL of the hybrid TFLN micro-ring AOM is as small as 9 mV·cm. Accordingly, the acousto-optic coupling strength is estimated to be 0.48 Hz s1/2 at acoustic frequency of 0.84 GHz. By analyzing the generation of phonon number from the piezoelectric transducer, the microwave-to-optical conversion efficiency is calculated to be 0.05%, approximately one order of magnitude larger than that of the state-of-the-art suspended counterpart. Efficient microwave-to-optical conversion thus provides new opportunities for low-power-consumption quantum information transduction using the TFLN-ChG hybrid piezo-optomechanical devices. © 2024, CC BY.

关键词： Thin films

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Turning a hot spot into a cold spot:polarization-controlled Fano-shaped local-field responses probed by a quantum dot

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Light(Science & Applications) 2020年第1期9卷 417-428页

作者： Juan Xia Jianwei Tang Fanglin Bao Yongcheng Sun Maodong Fang Guanjun Cao Julian Evans Sailing He Centre for Optical and Electromagnetic Research State Key Laboratory of Modern Optical InstrumentationNational Engineering Research Center for Optical InstrumentationJORCEPCollege of Optical Science and EngineeringZhejiang University310058 HangzhouChina School of Physics Huazhong University of Science and Technology430074 WuhanChina Centre for Optical and Electromagnetic Research ZJU-SCNU Joint Center of PhotonicsSouth China Academy of Advanced OptoelectronicsSouth China Normal University510006 GuangzhouChina Department of Electromagnetic Engineering School of Electrical EngineeringRoyal Institute of TechnologyS-10044 StockholmSweden

Optical nanoantennas can convert propagating light to local *** local-field responses can be engineered to exhibit nontrivial features in spatial,spectral and temporal domains,where local-field interferences play a key ***,we design nearly fully controllable local-field interferences in the nanogap of a nanoantenna,and experimentally demonstrate that in the nanogap,the spectral dispersion of the local-field response can exhibit tuneable Fano lineshapes with nearly vanishing Fano dips.A single quantum dot is precisely positioned in the nanogap to probe the spectral dispersions of the local-field *** controlling the excitation polarization,the asymmetry parameter q of the probed Fano lineshapes can be tuned from negative to positive values,and correspondingly,the Fano dips can be tuned across a broad spectral ***,at the Fano dips,the local-field intensity is strongly suppressed by up to ~50-fold,implying that the hot spot in the nanogap can be turned into a cold *** results may inspire diverse designs of local-field responses with novel spatial distributions,spectral dispersions and temporal dynamics,and expand the available toolbox for nanoscopy,spectroscopy,nano-optical quantum control and nanolithography.

关键词： quantum local dispersion

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A method for power system transient stability assessment based on transfer learning

A method for power system transient stability assessment bas...

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2020 IEEE Power and Energy Society General Meeting, PESGM 2020

作者： Ren, Junyu Chen, Jinfu Li, Benyu Zhao, Ming Shi, Hengchu You, Hao Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China Yunnan Electric Power Dispatching and Controlling Center Kunming China

ISBN: (纸本)9781728155081

Traditional machine learning models are subject to changes in the data distribution. Once the topology of power grid changes, the distribution of power grid data will change, resulting in the consequence that the former transient stability assessment model based on machine learning is no longer applicable and needs to be retrained. However, the power network after the topology changes cannot provide enough data for the training of the new model. To solve the problem above, this paper proposes a method of power system transient stability assessment based on transfer learning, which fully taps the potential of past data and assists a small amount of newly acquired data in training the model. The simulation results on the CEPRI36 system show that the proposed method can effectively improve the accuracy of original classification models, especially for weak classifiers with insufficient generalization ability. The disadvantage of transfer learning lies in the long training time, which still needs to be improved. © 2020 IEEE.

关键词： Topology

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The Modern Control technology of the Linear Generator for Oceanic Wave Energy Conversion System 13

The Modern Control Technology of the Linear Generator for Oc...

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13th International Symposium on Linear Drives for Industry Applications, LDIA 2021

作者： Farrok, Omar Kiran, Mahbubur Rahman Islam, Md. Rabiul Xu, Wei Department of Electrical and Electronic Engineering Ahsanullah University of Science and Technology Tejgaon I/A Dhaka1208 Bangladesh Department of Electrical and Electronic Engineering Green University of Bangladesh Dhaka Bangladesh School of Electrical Computer and Telecommunications Engineering Faculty of Engineering and Information Sciences University of Wollongong NSW2522 Australia State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan430074 China

ISBN: (纸本)9781728172101

Electrical power generation from the oceanic wave is one of the noteworthy footsteps in the field of renewable energy resource based energy conversion system. There are different technologies regarding electricity generation by using linear electrical generators along with the wave energy devices. This paper presents various control technologies of the linear generator that are widely been used for harvesting oceanic wave energy. Several controllers are discussed that are used to control the voltage, current, and power flow of the linear generator. Mathematical models of different controllers are discussed. Connection of the controller with the linear generator, input, output, outcome, and method of the controller with their pros and cons are presented as well. In addition, testing devices and their controls for the linear generator are presented with their schematic diagram. This paper would play vital role to the researcher for the future development of the linear generator for oceanic wave energy conversion. © 2021 IEEE

关键词： Controllers

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Efficient Model Training in Edge Networks with Hierarchical Split Learning

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IEEE Transactions on Mobile Computing 2025年

作者： Zhang, Songge Wu, Wen Song, Lingyang Shen, Xuemin Peking University Shenzhen Graduate School School of Electronic and Computer Engineering Shenzhen518055 China Pengcheng Laboratory Frontier Research Center Shenzhen518055 China Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Beijing100871 China Xiangtan University Hunan Institute of Advanced Sensing and Information Technology Xiangtan China University of Waterloo Department of Electrical and Computer Engineering WaterlooN2L 3G1 Canada

In this paper, we propose an efficient model training scheme, named Group-based Hierarchical Split Learning (GHSL), which can accelerate the artificial intelligence (AI) training process in edge networks in a "first-sequential-then-parallel" manner. Specifically, the proposed scheme hierarchically splits an AI model into a user-side and server-side model, while dividing a number of users into multiple groups. Users in each group train user-side models with the interaction of the shared server-side model sequentially;different groups perform the above training process parallelly;the AI models of each group are aggregated into a global model. We also carry out the convergence analysis for the proposed scheme over non-independent and identically distributed data, which reveals that the convergence rate depends on user grouping. Furthermore, we propose a data-driven two-stage user grouping algorithm to minimize the overall training delay, taking user resource heterogeneity and the black-box training process into account. The proposed algorithm first utilizes the Gaussian process regression approach to determine the number of groups, and then employs the coalition game theory to determine the optimal user grouping decision. Comprehensive simulation results demonstrate that the proposed scheme can reduce training delay, user-side computational workload, and communication overhead by up to 19%, 53%, and 54%, respectively, comparing to state-of-the-art benchmarks. © 2002-2012 IEEE.

关键词： Game theory

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advanced single-crystal layered Ni-rich cathode materials for next-generation high-energy-density and long-life Li-ion batteries

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Physical Review Materials 2022年第7期6卷 070201-070201页

作者： Jianming Sun Xin Cao Haoshen Zhou Energy Technology Research Institute National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba 305-8568 Japan Graduate School of System and Information Engineering University of Tsukuba 1-1-1 Tennoudai Tsukuba 305-8573 Japan Center of Energy Storage Materials & Technology College of Engineering and Applied Sciences Jiangsu Key Laboratory of Artificial Functional Materials National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 People's Republic of China

Benefiting from the high specific capacity and output voltage, Ni-rich layered oxides are one of the most promising commercial cathodes for next-generation high-energy-density Li-ion batteries (LIBs). However, typical Ni-rich cathode materials generally inherit polycrystal (PC) morphology from their precursors, which induces severe crack generations and side reactions, resulting in the rapid decay of structural and electrochemical stability upon cycling. In contrast, the Ni-rich cathodes with single-crystal (SC) morphology display remarkable structural stability and long cycle life by means of superior mechanical strength and limited side reactions, which is expected to solve the instinctive problems of PC counterparts. Herein, the synthesis strategies and the growth mechanisms of SC Ni-rich oxides are introduced and summarized in detail. Moreover, the significant differences in electrochemical behaviors between PC and SC cathodes are comprehensively compared in various voltage windows. Furthermore, the corresponding structural evolutions and morphology changes are also systematically investigated and analyzed. Additionally, the state-of-the-art characterization techniques for SC materials are elaborated. Altogether, in this review, we not only unravel the fundamental understandings of SC Ni-rich cathode materials but also provide an effective guide for realizing high-energy-density LIBs with long cycle life.

关键词： Electrochemical properties

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Application of 3D MHD equilibrium calculation to RMP experiments in the J-TEXT tokamak

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Plasma Science and technology 2021年第8期23卷 70-81页

作者： Zhaosu WANG Yunfeng LIANG Zhonghe JIANG Jie HUANG Yasuhiro SUZUKI Alexander KNIEPS Song ZHOU Jinyu XIONG Jiankun HUA Zhipeng CHEN Zhongyong CHEN Nengchao WANG Zhoujun YANG Yonghua DING Yuan PAN International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China Forschungszentrum Jülich GmbH Institute für Energie-und Klimaforschung—Plasmaphysik52425 JülichGermany Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China National Institutes of Fusion Sciences National Institutes of Natural SciencesOroshi-cho322-6Toki 509-5292Japan SOKENDAI The Graduate University for Advanced StudiesOroshi-cho322-6Toki 509-5292Japan Chengdu University Chengdu 610106People's Republic of China

The application of resonant magnetic perturbation(RMP)coils could break the initial axisymmetry and change the magnetic topology in tokamak *** understand the plasma equilibrium response to the RMP fields,three-dimensional(3 D)non-linear magnetohydrodynamics equilibrium calculations have been carried out using the HINT code for an RMP field-penetration experiment on *** HINT code does not assume perfectly nested flux surfaces,and is able to consider directly the change of magnetic topology due to the RMP field *** between 3 D equilibrium calculations and experimental observations are *** magnetic topologies calculated by HINT were compared with the field topologies obtained from a vacuum approximation *** turns out that the effects of redistribution of plasma pressure and current due to the formation of magnetic islands at various resonant rational surfaces should be considered self-consistently for understanding the change of magnetic *** changes include changes in the shape and size of magnetic islands,and the distribution of stochastic fields around the magnetic islands and at the plasma boundary,which plays an important role for plasma-wall interactions.

关键词： 3D equilibrium RMP magnetic topology

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