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Thermal shock of subsurface material with plastic flow during scuffing

Friction 2023年第1期11卷 64-75页

作者： Chuanwei ZHANG Han ZHAI Dong SUN Dezhi ZHENG Xiaoli ZHAO Le GU Liqin WANG MIIT Key Laboratory of Aerospace Bearing Technology and Equipment Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150080China

The thermal shock of subsurface material with shear instability and severe plastic flow during scuffing was *** scuffing damage of M50 steel was tested using a high-speed rolling-sliding contact test rig,and the transient temperature during scuffing was calculated using the Fourier transform method considering the effects of both frictional heat and plastic *** results show that a thermal shock with a rapid rise and subsequent rapid decrease in the contact temperature is generated in the subsurface *** frictional power intensity generates a high temperature rise,leading to the austenitization of the subsurface ***,the plastic flow is generated in the subsurface layer under the high shear stress,and the resulting plastic strain energy generates a further temperature ***,a rapid decrease in the contact temperature quenches the material,resulting in clear shear slip bands and retained austenite in the subsurface layers of the M50 steel.

关键词： scuffing thermal shock high temperature plastic flow

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Enhancement mechanism of plastic stress in nanocrystalline metals using carbon nanotubes: Molecular simulation and characterization

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Science China Technological Sciences 2025年第5期68卷 106-116页

作者： Fei WANG Li LI Xinli JIANG Xuelin WANG Yujin HU State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and Technology College of Mechanical Engineering Taiyuan University of Technology

The instability of nanograined metals and the degradation of their mechanical properties primarily arise from pronounced grain boundary(GB) sliding and migration at extremely small grain sizes(GS). This study explores the incorporation of carbon nanotubes(CNTs) into nanocrystalline metals to enhance plastic flow stress by impeding metal deformation. The results demonstrate that CNTs increase the critical stress of pure polycrystalline metals as GS increases. The relationship between plastic flow stress and GS in the composites is modeled using Hall-Petch and inverse Hall-Petch frameworks. As GS increases, the dominant plastic strengthening mechanism transitions from GB sliding hindrance via CNTs to a combined effect that mitigates GB sliding and intragranular stacking faults. Additionally, the study evaluates how CNT length, wall number, and functionalization influence plastic strengthening. Hence, these findings provide a theoretical foundation for the design of mechanically stable nanocrystalline metal composites.

关键词： nanocrystalline metal carbon nanotube molecular dynamics microstructure analysis grain boundary sliding

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A MIMO Neural Network Integrated with Maximum Likelihood Phase Recovery for Transoceanic Coherent Transmission

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Journal of Lightwave technology 2025年第12期43卷 5536-5544页

作者： Wang, Kaihui Wang, Chen Zheng, Tianqi Long, Jianyu Sang, Bohan Zhou, Wen Yu, Jianjun Fudan University State Key Laboratory of ASIC and System School of Information Science and Technology Shanghai200433 China

We proposed a low-complexity multi-input multi-output neural network integrated with a maximum likelihood phase recovery algorithm (MIMO-NN-BMLPR), which is adopted in long-haul coherent optical communication. Neural network based equalization can effectively overcome the nonlinear distortions induced during long-haul transmission. However, the forward neural network equalizer is difficult to track the phase of coherent optical signals. We integrate an additional maximum likelihood phase recovery layer with the MIMO-NN structure so that the phase noise can be compensated. In this work, 8-channel 100-GBaud dual-polarization (DP) PS-16QAM signals are successfully transmitted over 6400km and satisfy the normalized generalized mutual information (NGMI) threshold at 0.86. The proposed MIMO-NN-BMLPR integrates the low-complexity phase estimation with the NNE to improve the performance. Compared with the traditional DSP structure, the proposal prolongs the distance by 48.84% with a 39.80% complexity reduction. © 1983-2012 IEEE.

关键词： Optical communication

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Microscopic strengthening and failure mechanisms of graphene/Al composite: A molecular dynamics study

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Progress in Natural Science:Materials International 2024年第4期34卷 720-730页

作者： Huijuan Guo Xiaoyan Sun Liang Chen Yuhui Zhao Kaiqiang Shen Xiangshan Kong State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University Intelligent Manufacturing Department Yantai Engineering and Technology College

This study focused on the microscopic strengthening and failure mechanisms of the Al matrix reinforced by graphene(Gr), and the effects of number of layers, chirality, and arrangement of Gr were calculated based on the molecular dynamics simulation. The results revealed that the Young's modulus and yield strength were significantly enhanced by the addition of Gr. In Gr/Al composites with monolayer Gr, the zigzag Gr exhibited a better ultimate strain than the armchair Gr, indicating that the plastic deformation was affected by the chirality, and the dislocation hindrance and load transfer were the dominated strengthening mechanisms. The crack in the armchair Gr was limited to follow straight paths, while that in zigzag Gr extended in a petal-like manner across multiple directions. In Gr/Al composite with multilayer Gr, the dispersing Gr showed a stronger strengthening effect than the stacking Gr, and the strengthening effect increased with increasing the volume fraction of Gr. The dispersing Gr strongly hindered the movement of dislocations, while the Al matrix in the composite with stacking Gr could retard the folding of Gr. Moreover, Gr nanosheets fractured layer by layer rather than simultaneously fractured in the Gr/Al composites with multilayer Gr.

关键词： Molecular dynamics Gr/Al composites Strengthening Failure

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Experimental demonstration of 220-GHz terahertz signals wireless transmission over 4.6 km

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Science China(Information Sciences) 2025年第1期68卷 386-388页

作者： Yi WEI Jianjun YU Mingxu WANG Xiongwei YANG Qiutong ZHANG Jingwen TAN Bing ZHANG Ying WU Yang HAN Peng TIAN Wen ZHOU Kaihui WANG Feng ZHAO State Key Laboratory of ASIC and System Key Laboratory for Information Science of Electromagnetic Waves (MoE)School of Information Science and Technology Fudan University School of Electronic Engineering Xi'an University of Posts and Telecommunications

The advancement of terahertz (THz) communication technology drives the evolution of wireless communication systems,offering novel pathways and technical means for the development of future 6G communication *** wireless communication systems are often constrained by bandwidth limitations of electronic devices in high frequency ***,THz communication technology leverages the characteristics of electromagnetic waves to transcend these limitations,enabling communication athigher frequencies and wider bandwidths.

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Fast electrothermal coupling calculation method for supporting digital twin construction of electrical equipment

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High Voltage 2023年第2期8卷 390-400页

作者： Xiaosong Zhu Youyuan Wang Ruixiao Meng Shi Long Shaowen Wu State Key Laboratory of Power Transmission Equipment and System Security and New Technology(Chongqing University) ChongqingChina

The failure of electrical equipment directly or indirectly caused by overheating has become one of the main reasons for equipment *** real-time condition monitoring method of electrical equipment based on digital twin(DT)has received extensive attention and is considered as a technology with great engineering values and excellent application ***,the current calculation of DT mostly relies on the traditional finite element method(CFEM).This method becomes less computationally efficient as the size of the DT increases,especially for electrical equipment with high *** is difficult to meet the requirements real-time calculation in ***,starting from the algorithm optimization and parallel architecture,based on the weighted residual method and stabilised conforming nodal integration,a novel discrete method of electrothermal coupling equation is proposed and the data storage structure of the algorithm from the bottom layer is redesigned,and the corresponding GPU and multi-core CPU parallel framework are ***,taking the high voltage bushing as an example,the correctness of the method in this paper is verified by the CFEM code and commercial software *** the same grid and accuracy requirement,the calculation time is shortened by at least five times than *** the method is easy to extend to other types of multi-physics calculations.

关键词： electrical coupling method

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WaveCRNet: Wavelet Transform-Guided Learning for Semantic Segmentation in Adverse Railway Scenes

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IEEE Transactions on intelligent Transportation systems 2025年第6期26卷 8794-8809页

作者： Wang, Zhangyu Liao, Zhihao Wang, Pengcheng Chen, Peng Luo, Wenwen Beihang University State Key Laboratory of Intelligent Transportation System School of Transportation Science and Engineering Beijing100191 China Beihang University School of Cyber Science and Technology Beijing100191 China

Semantic segmentation is pivotal in autonomous train perception, significantly impacting the system's intelligence and reliability. However, its performance in railway scenes is hindered by various challenges, including severe weather conditions, low-light situations, tunnel settings, and diverse and dynamic unstructured scenes. To address these challenges, this study proposes WaveCRNet, a novel architecture for real-time semantic segmentation in challenging conditions, simulating wavelet-constrained PID controller in feature and wavelet space. This study first designs an effective wavelet information enhancement algorithm using a differentiable wavelet transform to bridge the gap between the wavelet and feature information domains. Then, the wavelet-guided attention pag module (WAPM) is introduced to guide the learning and fusion of detailed features based on wavelet priors. Moreover, the traditional wavelet transforms are spectral aliasing and shift sensitivity. Inspired by dual-tree complex wavelet transform (DTCWT), the DTCWT-based channel reconstruction module (DCRM) is designed to assist the channel-based learning of boundary information from coarse to fine. Finally, the proposed architecture is evaluated by the public dataset RailSem19. The experimental results validate the consistent performance gains between accuracy and inference speed, improving by 63.7% mIoU and 87 FPS, surpassing those of the advanced methods for real-time segmentation. © 2000-2011 IEEE.

关键词： Semantic Segmentation

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Identifying the real fracture hidden in rock microcrack zone by acoustic emission energy

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International Journal of Mining Science and technology 2024年第6期34卷 731-746页

作者： Yuekun Xing Bingxiang Huang Guangqing Zhang Binghong Li Hang Xu Xuejie Jiao Yang Yu Taisen Han Jinlong Chen State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing 102249China

Identifying the real fracture of rock hidden in acoustic emission(AE)source clusters(AE-depicted microcrack zone)remains challenging and *** we revealed the AE energy(representing dissipated energy)distribution rule in the rock microcrack zone and proposed an AE-energy-based method for identifying the real fracture.(1)A set of fracture experiments were performed on granite using wedgeloading,and the fracture process was detected and recorded by *** microcrack zone associated with the energy dissipation was characterized by AE sources and energy distribution,utilizing our selfdeveloped AE analysis program(RockAE).(2)The accumulated AE energy,an index representing energy dissipation,across the AE-depicted microcrack zone followed the normal distribution model(the mean and variance relate to the real fracture path and the microcrack zone width).This result implies that the nucleation and coalescence of massive cracks(i.e.,real fracture generation process)are supposed to follow a normal distribution.(3)Then,we obtained the real fracture extension path by joining the peak positions of the AE energy normal distribution curve at different cross-sections of the microcrack ***,we distinguished between the microcrack zone and the concealed real fracture within *** deviation was validated as slight as 1–3 mm.

关键词： GeoEnergy exploitation Rock fracture Fracture identification Acoustic emission AE energy analysis

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A Stability-guaranteed Model Predictive Control for Autonomous Surface Vessel Trajectory Tracking based on Lyapunov Theory

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IEEE Transactions on Transportation Electrification 2025年第3期11卷 7885-7896页

作者： Chen, Linying Qiu, Qianqian Li, Mengxia Chen, Pengfei Huang, Yaming Mou, Junmin Wuhan University of Technology State Key Laboratory of Maritime Technology and Safety School of Navigation Wuhan430063 China Wuhan University of Technology State Key Laboratory of Maritime Technology and Safety Intelligent Transportation Systems Research Center Wuhan430063 China

This article explores the trajectory tracking problem of an Autonomous Surface Vessel (ASV). As an optimization-based time-domain method, Model Predictive Control (MPC) has incomparable advantages in solving constrained multi-input multi-output system problems. However, ensuring the stability of the MPC is challenging. This article proposes a Stability-Guaranteed Model Predictive Control (SMPC) method by adding the Lyapunov constraint into the linearized MPC framework. The Lyapunov constraint transformed from the backstepping control law restricts the first action of MPC to guarantee closed-loop stability. Furthermore, the stability and recursive feasibility conditions are theoretically derived. Simulation results demonstrate that the proposed SMPC has better tracking and robustness compared with the backstepping methods. © 2025 IEEE.

关键词： Predictive control systems

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High-density, high-frequency and large-scale electrohydrodynamic drop-on-demand jetting via a protruding polymer-based printhead design

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Microsystems & Nanoengineering 2024年第6期10卷 267-277页

作者： Yongqing Duan Weili Yang Qiming Wang Zhaoyang Sun Haoyu Guo Zhouping Yin State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhanChina Flexible Electronics Research Center Huazhong University of Science and TechnologyWuhanChina

Electrohydrodynamic(EHD)printing has critical merits in micro/nanoscale additive manufacturing because of its ultrahigh resolution and wide ink compatibility,making it an advantageous choice for electronics manufacturing,high-resolution prototyping,and biological component ***,EHD printing is currently limited by its rather low throughput due to the lack of high-frequency and high-density multi-nozzle *** paper presents a novel EHD printhead with a protruding polymer-based nozzle *** insulated,hydrophobic,and protruding polymer nozzle array with an appropriate geometric structure can effectively address key problems in multi-nozzle jetting,such as electrical crosstalk,electrical discharge,liquid flooding,and nonuniform *** investigating the influence of the electrical and geometric characteristics of the nozzle arrays on the electrical crosstalk behavior and fabricating the optimized nozzle array via MEMS technology,we achieve an EHD printhead with a large scale(256),high density(127 dpi),and high jetting frequency(23 kHz),and addressable jetting can be realized by adding independently controllable extractors underneath the nozzle *** functional materials,such as quantum dots,perovskite,and nanosilver inks,can be ejected into high-resolution patterns through the optimized nozzle array,demonstrating the great prospects of our designed printhead in electronics *** MEMS-compatible printhead design lays the foundation for high-throughput fabrication of micro/nanostructures and promotes practical applications of EHD printing in functional electronics and biomedical/energy devices.

关键词： printing nozzle electronics

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