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arXiv 2025年

作者： Zhong, Xin Lin, Weiwei Pan, Kejia Wu, Pinxia Zhang, Jiajing Zhan, Zhiliang Xiao, Wenbo School of information engineering Jiangxi University of Science and Technology Ganzhou341000 China Jiangxi College of Applied Technology Ganzhou341000 China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural Resources Ganzhou341000 China Hunan Shaofeng Institute for Applied Mathematics Xiangtan411105 China School of Mathematics and Statistics HNP-LAMA Central South University Changsha410083 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100088 China School of science Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China

—Traditional three-dimensional magnetotelluric (MT) numerical forward modeling methods, such as the finite element method (FEM) and finite volume method (FVM), suffer from high computational costs and low efficiency due to limitations in mesh refinement and computational resources. We propose a novel neural network architecture named MTAGU-Net, which integrates an attention gating mechanism for 3D MT forward modeling. Specifically, a dual-path attention gating module is designed based on forward response data images and embedded in the skip connections between the encoder and decoder. This module enables the fusion of critical anomaly information from shallow feature maps during the decoding of deep feature maps, significantly enhancing the network’s capability to extract features from anomalous regions. Furthermore, we introduce a synthetic model generation method utilizing 3D Gaussian random field (GRF), which accurately replicates the electrical structures of real-world geological scenarios with high fidelity. numerical experiments demonstrate that MTAGU-Net outperforms conventional 3D U-Net in terms of convergence stability and prediction accuracy, with the structural similarity index (SSIM) of the forward response data consistently exceeding 0.98. Moreover, the network can accurately predict forward response data on previously unseen datasets models, demonstrating its strong generalization ability and validating the feasibility and effectiveness of this method in practical applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Decoding

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Interfacial Thermal Transport and Energy Dissipation in Multilayer PdSe2 Field Effect Transistors

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Advanced Materials 2025年第0期 e2503264页

作者： Xie, Jiaqiu Yu, Zehao Sun, Yuanchen Gan, Qikang Liu, Chenhan Wang, Lei Zhang, Lifa Zhao, Yunshan Phonon Engineering Research Center of Jiangsu Province Ministry of Education Key Laboratory of NSLSCS Center for Quantum Transport and Thermal Energy Science Institute of Physics Frontiers and Interdisciplinary Sciences School of Physics and Technology Nanjing Normal University Nanjing210023 China National Laboratory of Solid-State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Micro- and Nano-scale Thermal Measurement and Thermal Management Laboratory Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems School of Energy and Mechanical Engineering Nanjing Normal University Nanjing210046 China

The continuous miniaturization of 2D electronic circuits results in increased power density during device operation, leading to heat localization and placing higher demands on their performance thresholds. The risk to thermal breakdown and subsequent damage, due to the energy dissipation in the 2D semiconductor field-effect transistors (FETs) supported on the bulk substrates, represents a significant challenge in maintaining their optimal performance. Herein, this study investigates energy dissipation behavior in multilayer PdSe2 FETs for the first time. The high-field breakdown behavior is firstly studied in multilayer PdSe2 FETs on SiO2/Si substrates, where a maximum current density of ≈2.74 MA cm−2 is observed, which is comparable to that of multilayer black phosphorus FET and significantly higher—by about five times—than that of multilayer MoS2 FET. Additionally, the thermal boundary conductance (TBC) of PdSe2/SiO2 interface is measured at room temperature using Raman thermometry. The TBC is found to be ≈12–13 MW m−2 K−1, which is relatively low compared to the other known solid–solid interfaces, indicating that enhancing the performance of PdSe2 FETs can be possible by optimizing the TBC at the PdSe2/SiO2 interface. These findings provide valuable insights for design of high-quality and high-performance PdSe2 electronic and optoelectronic devices. © 2025 Wiley-VCH GmbH.

关键词： Multilayers

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Two-mode terms in Wigner transport equation elucidate anomalous thermal transport in amorphous silicon

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Physical Review B 2025年第9期111卷 094206-094206页

作者： Jin Yang Xueyan Zhu Alan J. H. McGaughey Yee Sin Ang Wee-Liat Ong ZJU-UIUC Institute College of Energy Engineering Zhejiang University Jiaxing Haining Zhejiang 314400 China China Academy of Engineering Physics Software Center for High Performance Numerical Simulation Beijing 100088 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Mechanical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Science Mathematics and Technology Singapore University of Technology and Design 487372 Singapore State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou Zhejiang 310027 China

Over the past decades, our understanding of thermal transport in amorphous materials has predominantly relied on the inherently harmonic Allen-Feldman theory, which has been found to be insufficient. In this study, the Wigner transport formalism is adopted to explicitly account for anharmonicity. In studying the thermal transport in amorphous silicon, the results highlight that amorphous materials are not generally computationally equivalent to crystals with disordered primitive cells. A method that leverages the properties of the two-mode terms in the Wigner transport formalism is proposed to predict the bulk thermal conductivity of amorphous materials using finite-size models. In doing so, the need for mode classification schemes required in the Allen-Feldman theory is eliminated, and similarities are discovered between the two-mode terms and the carriers commonly used to describe thermal transport in amorphous materials, i.e., propagons, diffusons, and locons. Two competing trends are identified that shed light on the recently discovered anomalous decrease in the high-temperature thermal conductivity in some amorphous materials.

关键词： Heat transfer

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Varying contributions of fast and slow responses cause asymmetric tropical rainfall change between CO_(2) ramp-up and ramp-down

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science Bulletin 2022年第16期67卷 1702-1711,M0004页

作者： Shijie Zhou Ping Huang Shang-Ping Xie Gang Huang Lin Wang Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100190China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Scripps Institution of Oceanography University of California San DiegoLa Jolla CA 92093USA Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Tropical rainfall is important for regional climate around the *** a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally ***,we analyze an idealized CO_(2) removal experiment from the Carbon Dioxide Removal Model Intercomparison Project(CDRMIP)and show that the tropical rainfall change features a stronger pattern during CO_(2) ramp-down than ramp-up,even under the same global mean temperature increase,such as the 2℃ goal of the Paris *** tropical rainfall during CO_(2) ramp-down increases over the equatorial Pacific with a southward extension,and decreases over the Pacific intertropical convergence zone and South Pacific convergence *** asymmetric rainfall changes between CO_(2) ramp-down and ramp-up result from time-varying contributions of the fast and slow oceanic responses to CO_(2) forcing,defined as the responses to abrupt CO_(2) forcing in the first 10 years and thereafter,respectively,in the abrupt-4xCO_(2) *** fast response follows the CO_(2) evolution,but the slow response does not peak until 60 years after the CO_(2) *** slow response features a stronger El Niño-like pattern,as the ocean dynamical thermostat effect is suppressed under stronger subsurface *** delayed and stronger slow response leads to stronger tropical rainfall changes during CO_(2) *** results indicate that returning the global mean temperature increase to below a certain goal,such as 2℃,by removing CO_(2),may fail to restore tropical convection distribution,with potentially devastating effects on climate worldwide.

关键词： Tropical rainfall Fast and slow responses Sea surface warming pattern CDRMIP

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Resolved magnetohydrodynamic wave lensing in the solar corona

arXiv

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arXiv 2024年

作者： Zhou, Xinping Shen, Yuandeng Yuan, Ding Keppens, Rony Zhao, Xiaozhou Fu, Libo Tang, Zehao Wang, Jiaoyang Zhou, Chengrui College of Physics and Electronic Engineering Sichuan Normal University Chengdu610068 China Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Shenzhen Key Laboratory of Numerical Prediction for Space Storm Institute of Space Science and Applied Technology Harbin Institute of Technology Guangdong Shenzhen China Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Beijing China Centre for mathematical Plasma Astrophysics Department of Mathematics KU Leuven Celestijnenlaan 200B LeuvenB-3001 Belgium

Electromagnetic wave lensing, a common physical phenomenon recognized in visible light for centuries, finds extensive applications in manipulating light in optical systems such as telescopes and cameras. Magnetohydrodynamic wave is a common perturbation phenomenon in the corona. By using high spatio-temporal resolution observations from the Solar Dynamics Observatory, here, we report the observation of a magnetohydrodynamic wave lensing in the highly ionized and magnetized coronal plasma, where quasi-periodic wavefronts emanated from a flare converged at a specific point after traversing a coronal hole. The entire process resembles an electromagnetic wave lensing from the source to the focus. Meanwhile, the magnetohydrodynamic wave lensing is well reproduced through a magnetohydrodynamic numerical simulation with full spatio-temporal resolution. We further investigate potential applications for coronal seismology, as the lensing process encodes information on the Alfvén speed, in conjunction with favorable geometric and density variations. Copyright © 2024, The Authors. All rights reserved.

关键词： Electromagnetic waves

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Graph-GIC: A Smart and Parallelized Geomagnetically Induced Current Modelling Algorithm Based on Graph Theory for Space Weather Applications

arXiv

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arXiv 2024年

作者： Chen, Wen Yuan, Ding Feng, Xueshang Poedts, Stefaan Zou, Zhengyang Feng, Song Zhu, Yuxuan Yin, Tong Shenzhen Key Laboratory of Numerical Prediction for Space Storm School of Aerospace Harbin Institute of Technology Guangdong Shenzhen518055 China Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Beijing China Centre for Mathematical Plasma Astrophysics Department of Mathematics KU Leuven LeuvenB-3001 Belgium State Key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology China Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming650500 China Institute of Physics University of Maria Curie-Sklodowska ul. Marii Curie-Sklodowskiej 1 Lublin20-031 Poland

Geomagnetically Induced Current (GIC) refers to the electromagnetic response of the Earth and its conductive modern infrastructures to space weather and would pose a significant threat to high-voltage power grids designed for the alternative current operation. To assess the impact of space weather on the power grid, one needs to calculate the GIC on a national or continental scale. In this study, we developed a smart and parallelized GIC modelling algorithm, Graph GIC. This algorithm deploys a graph representing a power grid in a single-line diagram, in which substations/transformers act as nodes and transmission lines as edges. With these denotations, a power grid and its electric parameters are mathematically represented with an adjacency matrix and an admittance matrix. We used sparse matrix and parallelisation techniques to expedite the intensive computation in cases of large-scale power grids. The Graph GIC was validated with a benchmark grid, applied to the GIC calculation of the 500 kV power grid of Guangdong, China, and conducted preliminary analysis on the grid’s susceptibility to geomagnetic storms. The Graph GIC algorithm has the advantage of an intuitive and highly scalable graph representation of a power grid at any scale. It achieves high-accuracy calculation and a speedup of about 18 times after parallelisation. This algorithm could be applied to assess the impact of space weather on a power grid up to continental scales and could be incorporated into global space weather modelling frameworks. Copyright © 2024, The Authors. All rights reserved.

关键词： Matrix algebra

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Dual-Frequency Vortex Beam Generation Using Coding Metasurface

Dual-Frequency Vortex Beam Generation Using Coding Metasurfa...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Junfeng Li Xianglin Kong Fengjun Wang Zhuowei Miao Xiaoyi Wang Xiaopeng Shen Shengjun Zhang Lei Zhao School of Information and Control Engineering China University of Mining and Technology Xuzhou China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China School of Information Science and Engineering Southeast University Nanjing China Department of Electrical Engineering Polytechnique Montreal Montreal Quebec Canada School of Materials Science and Physics China University of Mining and Technology Xuzhou China

This paper presents a dual-frequency coding metasurface (CM) for vortex beam generation. The metasurface unit cell is realized with two symmetric metal layers separated by a dielectric substrate. Each metal layer consists of an outer square ring, a middle square ring, and an inner rhombus patch. Two out-of-phase transmitting states in two bands are achieved by rotating the inner rhombus patch by 90 °. Two 1 = + 2 vortex beams are then realized in two different bands by properly distributing the two states on the metasurface aperture. A metasurface with $30 \times 30$ elements is designed, simulated, and experimentally demonstrated. The experimental results agree well with the simulating ones, showing that the metasurface achieves a high transforming efficiency in both Ku (13.6-14.8GHz) band and Ka (26.7-27.7 GHz) band.

关键词： Wireless communication Electric potential Analytical models Computational modeling Dielectric substrates Metals Apertures

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Research on dual-polarisation printed dipole antenna for spherical near-field measurements

Research on dual-polarisation printed dipole antenna for sph...

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IET International Radar Conference 2018, IRC 2018

作者： Zheng, Pei Liu, JiaQi Wang, ShangYue Zhang, Ran Fan, Hu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

Here a dual-polarisation printed dipole antenna for spherical near-field measurements is proposed. The printed dipole employs double-layered structure to obtain low cross-polarisation and uses irregular patch to get wide bandwidth. Two such dipoles are cross arranged to form a dual-polarisation dipole antenna. Simulated results show that the bandwidth is over 72% when VSWR is less than 3, the cross-polarisation ratio is better than 30 dB, the port isolation between two dipoles is better than −26 dB, while good radiation performance is also obtained. All the results above prove that the crossed arrangement structure will not affect the performance of the printed dipole, and the strength of mutual coupling between probes can be neglected. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Dipole antennas

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Research on near-field focusing algorithm of reconfigurable reflect-array

Research on near-field focusing algorithm of reconfigurable ...

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IET International Radar Conference 2018, IRC 2018

作者： Liu, Hong Yan Zheng, Pei Wang, Chao Guo, Lei Zhang, Xin Yu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In this study, the near-field beam focusing algorithm of reconfigurable reflect array for security imaging application is proposed. The proposed near-field focusing algorithm is based on classic array method, which is usually adopted for far-field pattern calculation. In order to satisfy the near-field imaging application, the imaging distance is added to array method, and the improved formula can calculate the shifting phase of every array element precisely. In addition, due to discrete phase characteristic of reconfigurable reflect array, a phase choice method based on trigonometric function is used in authors' design. Based on the proposed algorithm, the shifting phase of every element is calculated and obtained the simulated beam focusing patterns. Meanwhile, the calculated shifting phase is written to whole array by field-programmable gate array, the near-field beam scanning patterns is measured and the measured results are in good agreement with the simulated ones. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Field programmable gate arrays (FPGA)

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Thermodynamic nonequilibrium effects in three-dimensional high-speed compressible flows: Multiscale modeling and simulation via the discrete Boltzmann method

arXiv

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arXiv 2025年

作者： Guo, Qinghong Gan, Yanbiao Yang, Bin Wu, Yanhong Lai, Huilin Xu, Aiguo Fujian Normal University Fuzhou350117 China Hebei Key Laboratory of Trans-Media Aerial Underwater Vehicle North China Institute of Aerospace Engineering Langfang065000 China School of Energy and Safety Engineering Tianjin Chengjian University Tianjin300384 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P. O. Box 8009-26 Beijing100088 China National Key Laboratory of Shock Wave and Detonation Physics Mianyang621999 China HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing100081 China

Three-dimensional (3D) high-speed compressible flow is a typical nonlinear, nonequilibrium, and multiscale complex flow. Traditional fluid mechanics models, based on the quasi-continuum assumption and near-equilibrium approximation, are insufficient to capture significant discrete effects and thermodynamic nonequilibrium effects (TNEs) as the Knudsen number increases. To overcome these limitations, a discrete Boltzmann modeling and simulation method, rooted in kinetic and mean-field theories, has been developed. By applying Chapman-Enskog multiscale analysis, the essential kinetic moment relations Φ = (M0,M1,M2,0,M2,M3,1,M3,M4,2,M4,M5,3) for characterizing second-order TNEs are determined. These relations Φ are invariants in coarse-grained physical modeling, providing a unique mesoscopic perspective for analyzing TNE behaviors. A discrete Boltzmann model, accurate to second-order in the Knudsen number, is developed to enable multiscale simulations of 3D supersonic flows. As key TNE measures, nonlinear constitutive relations (NCRs), are theoretically derived for the 3D case, offering a constitutive foundation for improving macroscopic fluid modeling. The NCRs in three dimensions exhibit greater complexity than their two-dimensional counterparts. This complexity arises from increased degrees of freedom, which introduce additional kinds of nonequilibrium driving forces, stronger coupling between these forces, and a significant increase in nonequilibrium components. At the macroscopic level, the model is validated through a series of classical test cases, ranging from one-dimensional to 3D scenarios, from subsonic to supersonic regimes. At the mesoscopic level, the model accurately captures typical TNEs, such as viscous stress and heat flux, around mesoscale structures, across various scales and orders. This work provides kinetic insights that advance multiscale simulation techniques for 3D high-speed compressible flows. Copyright © 2025, The Authors. All rights reserve

关键词： Compressible flow

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