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Bauschinger effect in nano-grinding of 3C-SiC: A molecular dynamics study

Wear 2025年

作者： Zhao, Xiangyang Tang, Yunqing Chen, keyang Cai, Yukui Liang, Xiaoliang Liu, Zhanqiang Li, Dongyang School of Mechanical Engineering Shandong University Jinan250061 China State Key Laboratory of Advanced Equipment and Technology for Metal Forming Shandong University Jinan250061 China Key Laboratory of High Efficiency and Clean Mechanical Manufacture of Ministry of Education Jinan250061 China Key National Demonstration Center for Experimental Mechanical Engineering Education Jinan250061 China Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology Guilin University of Electronic Technology Guilin541004 China Department of Chemical and Materials Engineering University of Alberta EdmontonABT6G 2H5 Canada

The Bauschinger effect typically occurs in ductile materials and influences their tribological behaviors. However, this phenomenon is rarely reported in brittle materials. The nano-scale plastic deformation observed in brittle materials implies that the Bauschinger effect may also occur during their nano-tribological processes. In this study, molecular dynamics simulations were employed to evaluate the Bauschinger effect in cubic silicon carbide (3C-SiC) and its effect on nano-grinding of 3C-SiC. The results show that defects generated in 3C-SiC during shear deformation recover upon reversal of the shear direction, and defects near the surface of 3C-SiC workpiece generated during nano-grinding also recover upon reversal of the grinding direction, which validates the hypothesis that the Bauschinger effect may occur in 3C-SiC and could benefit its machinability. The Bauschinger effect during bi-directional grinding could help significantly reduce the damage and roughness to the surface of 3C-SiC and also help lower the machining resistance. Such benefits from the Bauschinger effect are found to be more pronounced at relatively lower temperatures, which makes the machinability of 3C-SiC during the bi-directional grinding at relatively lower temperatures comparable to that during the unidirectional grinding at higher temperatures. Therefore, taking advantage of the Bauschinger effect could help lower the operation temperature for high-quality and high-efficiency grinding of 3C-SiC with reduced defects, roughness, and resistance. This study provides an insight into the nano-tribological behaviors of brittle materials and demonstrates an effective approach for their ultra-precision machining. © 2025 Elsevier B.V.

关键词： Machinability

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Polarization-independent, high-NA edge detection with nonlocal metasurfaces

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Optics Letters 2025年第11期50卷 3517-3520页

作者： Yalong Liu Xiaoxin Li Bojian Shi Qi Jia Yanxia Zhang Yanyu Gao Wenya Gao Fangkui Sun Yongyin Cao Rui Feng Weiqiang Ding Institute of Advanced Photonics School of Physics Harbin Institute of Technology Harbin 150001 China Key Laboratory of Micro-Nano Optical-acoustic-electronic System of Ministry of Industry and Information Technology Harbin 150001 China fengrui_0223@*** Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 China

optical analog computing based on flat optical structures offers significant advantages in system miniaturization, loss reduction, and computational speed compared to traditional systems requiring complex optical configurations. However, existing metasurface schemes for analog image processing suffer from critical limitations, including polarization dependence, bandwidth constraints, and restricted numerical aperture (NA). In this work, we demonstrate a robust and easy-to-fabricate nonlocal dielectric metasurface, which can readily perform polarization-independent edge detection with extended bandwidth and high NA. The isotropic two-dimensional second-order differentiation operations under arbitrary polarization conditions, including unpolarized illumination, are realized by leveraging the magnetic dipole resonance (MD). This scheme enables real-time, high-quality edge detection, featuring a bandwidth of 48 nm centered at 1064 nm and a NA of up to 0.5. This work provides a novel, to the best of our knowledge, approach for achieving polarization-independent edge detection, paving the way for practical applications in optical computing and imaging systems.

关键词： Biomedical imaging Edge detection Imaging systems Machine vision optical computing optical imaging

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A study on the fretting wear characteristic of Inconcel 718 alloys formed by selective laser melting(SLM)

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Wear 2025年

作者： Xu, Zhi-biao Lu, Hao-wen Zeng, Xin-yi Wang, Xiao-yi Wu, Hao Peng, Jin-fang Zhu, Min-hao College of Intelligent Manufacturing Guangzhou Maritime University Guangzhou510725 China School of Rail Transportation Wuyi University Jiangmen529020 China Guangdong Key Laboratory of Materials and Equipment in Harsh Marine Environment School of Naval Architecture and Ocean Engineering Guangzhou Maritime University Guangzhou510725 China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu 610031 China Shandong Key Laboratory of Advanced Aluminum Materials and Technology Binzhou256606 China

The selective laser melting (SLM) technology has plays pivotal role in aerospace equipment, medical instrument, mold manufacturing and nuclear power industries due to its ability to rapidly fabricate intricate parts in recent *** methods like casting and forging often lead to Inconel 718 alloy parts with issues such as element segregation, coarse grain and structural simplicity. All such shortcomings are overcome by SLM technology, it's enabling to production Inconel 718 alloy parts with complex, fine grained and high density. Given the increasing reliance on SLM for creating Inconel 718 alloys, there is growing interest in the operational characteristics of these materials, including their mechanical, fatigue, and fretting wear properties. This study explores the fretting wear properties of Inconel 718 alloy produced by SLM, using an in-house designed fretting wear tester under various normal loads and displacement amplitudes. The coefficient of friction (COF) curve and friction force displacement (Ft-D) data during the fretting wear process were analyzed for a detailed dynamic responds. Additionally, the fretting wear damage and cross-section morphology were examined using a scanning electron microscope (SEM) and a three-dimensional profilometer (3D).The results show that the COF curve and Ft-D curve during the fretting wear process are greatly affected by the displacement amplitude and normal load. With the increase of normal load or the decrease of displacement amplitude, the fretting running state changes from the gross slip regime (GSR) to the mixed slip regime (MSR) and finally to the partial slip regime (PSR), and the most serious material damage occurs when the fretting state runs in the MSR. During the shift from the PSR to the MSR and the GSR, the fretting wear mechanism evolves from predominantly adhesive wear and abrasive wear to a dominance of fatigue wear and material delamination. The fretting wear damage of the material is influenced b

关键词： Fatigue damage

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Ultra-wide-field-of-view high-resolution cascaded spectral imaging system

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Optics Express 2025年第10期33卷 22030-22041页

作者： Xuhui Li Yanhong Gao Rudong Xue Yiqun Ji Shujun Sun School of Optoelectronic Science and Engineering Soochow University Suzhou 215006 China Collaborative Innovation Center of Suzhou Nano Science and Technology & Engineering Research Center of Digital Imaging and Display of Education Ministry of China Soochow University Suzhou 215006 China Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou 215006 China School of Optical and Electronic Information Suzhou City University & Suzhou Key Laboratory of Biophotonics Suzhou 215104 China Nanjing Research Institute on Simulation Technique Nanjing 210016 China jiyiqun@***

Spectral imaging combines the advantages of spectroscopy as an analytical tool with the two-dimensional object visualization obtained by optical imaging. At present, spectral imaging systems suffer from severe scale-dependent geometric aberrations. This prevents the simultaneous realization of a wide field of view (FOV) and high resolution. Here we propose an ultra-wide-FOV high-resolution cascaded spectral imaging system (URIS), which captures an ultra-wide-FOV panchromatic image with a folding monocentric lens and obtains high-resolution spectral images after local aberration correction by the spectral imaging sub-channels. The key issue of how the position of the aperture stop affects the illumination uniformity of the sub-channels has been studied, contributing to achieving the spectral images stitching between adjacent sub-channels and improving the performance of the processed spectral image. The URIS is optimally designed with 19 spectral imaging sub-channels to cover a full FOV of about 110°. It achieves an excellent spatial resolution of 0.075 mrad and a high spectral resolution of 4 nm theoretically. An experiment is also demonstrated to verify the wide FOV and the uniformity of sub-channels of URIS, confirming the correctness of the theoretical study. URIS has great advantages in spectral imaging of large macroscopic scenes, inspiring various machine vision applications.

关键词： Imaging systems optical components optical imaging optical systems Spatial resolution systems design

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Laser cladding WC/Fe composite coating on nose rail of turnout: Microstructure characteristics and wear behaviors

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Wear 2025年

作者： Ding, Haohao Cui, Tong Wang, Wenjian Lin, Qiang Wang, Liang Yang, Yi Yang, Wenbin Zhang, Qunli Xiao, Qian Qi, Huan Tribology Research Institute State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu610031 China Mechanical Industry Key Laboratory of Damage Mechanism and Protection Technology for High-speed Friction Pairs Southwest Jiaotong University Chengdu610031 China Institute of Laser Advanced Manufacturing Zhejiang University of Technology Hangzhou310023 China Chengdu Qingshi Laser Technology Co. Ltd Chengdu610213 China State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastucture East China Jiaotong University Nanchang330013 China

The nose rail of turnout is suffering from severe impact and sliding wear due to its irregular structure. As a surface repairing technology, laser cladding has an application possibility to improve the wear resistance. Furthermore, WC particles possess high hardness and good wettability with Fe-base alloys. Therefore, the laser cladding process of WC/Fe composite coating on nose rail is optimized and the wear behavior is explored. WC/Fe composite coatings with different WC contents (0-40 wt%) are produced on the nose rail material (high manganese steel) using a MMRO-2 fiber laser. It is found that with the increase in WC content, the microstructure size is reduced, the proportion of equiaxed dendrites is increased and the hardness is improved. When the WC content is increased to 40 wt%, cracks are formed during cladding. To solve this problem, three optimization methods are explored: adjustment of laser energy density, laser remelting and ultrasonic vibration assistance. The results show that the increase in the energy density, remelting power, vibration amplitude could reduce the number of cracks. Finally, impact and sliding tests are performed to study the wear behavior of WC/Fe composite coating. It is found that with the increase in WC content to 30 wt%, both the impact and sliding wear resistances of coating are enhanced. With the continuing increase to 40 wt%, the impact wear resistance is reduced but the sliding wear resistance is slightly increased. The impact damage form is predominated by spalling, and the sliding damage form is dominated by ploughing. Comparing the three optimization methods, laser remelting could reduce the wear resistant due to the decline of coating hardness. However, improving the vibration amplitude could increase the wear resistance due to the increased hardness and decreased microstructure size. © 2025 Elsevier B.V.

关键词： Manganese steel

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Hysteretic responses of nanomechanical resonators based on crumpled few-layer graphene

arXiv

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arXiv 2025年

作者： Lu, Heng Yang, Chen Zhang, Ce Zhang, YuBin Chen, FengNan Ying, Yue Zhang, Zhuo-Zhi Song, Xiang-Xiang Deng, Guang-Wei Yan, Ying Moser, Joel School of Optoelectronic Science and Engineering Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou215006 China Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou215006 China CAS Key Laboratory of Quantum Information 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 Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu610054 China

Manipulating two-dimensional materials occasionally results in crumpled membranes. Their complicated morphologies feature an abundance of folds, creases and wrinkles that make each crumpled membrane unique. Here, we prepare four nanomechanical resonators based on crumpled membranes of few-layer graphene and measure their static response and the spectrum of their dynamic response. We tune both responses with a dc voltage applied between the membrane and an underlying gate electrode. Surprisingly, we find that all four resonators exhibit hysteretic responses as the gate voltage is increased and then decreased. Concomitant discontinuities in the static response and in the vibrational resonant frequencies indicate a sudden change in the shape and in the tensile strain of the membranes. We also find that the hystereses can be removed and regular responses can be restored by annealing the resonators. We hypothesize that the hysteretic nature of the responses may originate from an interplay between the rugged morphology of the membranes and adsorbates trapped within the confine of the folds. © 2025, CC BY-NC-ND.

关键词： Tensile strain

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Optimizing edge-enabled system for detecting green passion fruits in complex natural orchards using lightweight deep learning model

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Computers and Electronics in Agriculture 2025年 234卷

作者： Li, Hongwei Chen, Jiasheng Gu, Zenan Dong, Tianyun Chen, Jiqing Huang, Junduan Gai, Jingyao Gong, Hao Lu, Zhiheng He, Deqiang School of Mechanical Engineering Guangxi University 100 Daxue East Road Nanning530004 China School of Artificial Intelligence South China Normal University Foshan528225 China Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology School of Mechanical Engineering Guangxi University Nanning530004 China College of Engineering South China Agricultural University 483 Wushan Road Guangzhou510641 China

To address labor shortages and rising costs, developing cost-effective fruit detection technology capable of functioning effectively in complex orchard environments is especially crucial for the advancement of robotic passion fruit harvesting systems. Moreover, achieving edge device-based efficient detection is highly expected under field conditions given its operating portability and cost-effective effects. This study proposed an improved YOLOv8n model for automatic passion fruits detection. First of all, a ParNet attention mechanism was added to the C2f module of YOLOv8n to improve feature extraction. To extract more information about small targets in the images, an additional detection layer was added for small targets in the Neck network. Furthermore, a SlimNeck architecture was employed to optimize the original neck part, reducing the model parameters while maintaining detection performance. The proposed model was trained and tested using a dataset divided by Hold-out, achieving an accuracy of 96.0 %, a recall rate of 83.7 %, and a mAP@0.5 of 91.9 %. The model size was optimal with 2,650,300 parameters, 10.4G FLOPs, and an inference speed of 115fps in Windows-based platform. Compared to the other state-of-the-art deep learning models such as YOLOv4-Tiny, YOLOv5n, YOLOv6n, YOLOv7-Tiny, YOLOv8n, YOLOv9, YOLOv10n, YOLOv11n, Faster R-CNN and SSD, the improved YOLOv8n model showcased overall superior detection performance. When deploying this proposed model on Nvidia Jetson Orin Nano, the inference speed of the improved model was 28.15fps in the C++ environment using the TensorRT API, showing real-time detection performance. This study can provide basic technology for passion fruit robotic harvesting on the basis of the potable edge devices. © 2025 Elsevier B.V.

关键词： Deep reinforcement learning

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Machine learning screening and DFT calculations for exploring Cs2Ag0.75X0.25BiCl6 (X=Na, K, Rb) double perovskites as underwater photovoltaic materials

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Solar Energy Materials and Solar Cells 2025年 289卷

作者： Chen, Changcheng Han, Zhao Xu, Yaxin Wang, Zhengjun Tuo, Yali Du, Yuxi Yun, Xiongfei Shi, Shaohang Xie, Jiangzhou Gao, Shuli Chen, Wen Dong, Chao Ji, Yuxiao Guan, Xiaoning Liu, Gang Lu, Pengfei School of Science Xi'an University of Architecture and Technology Xi'an710055 China MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter Key Laboratory for Advanced Materials and Mesoscopic Physics of Shaanxi Province School of Physics Xi'an Jiaotong University Xi'an710049 China School of Mechanical and Manufacturing Engineering University of New South Wales SydneyNSW2052 Australia State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Beijing100876 China Key Laboratory of Eco Planning & Green Building Ministry of Education Tsinghua University Beijing100080 China

Underwater vehicles, sensors, and autonomous systems heavily rely on stable energy supplies, which remain a key limiting factor in their practical applications. Traditional silicon-based solar cells are restricted in underwater applications due to their low light absorption efficiency and poor mechanical stability. In this study, we employed machine learning to screen perovskite materials with suitable bandgaps and constructed a vacuum-ordered Cs2AgBiCl6 double perovskite model. Subsequently, through first-principles calculations, we systematically investigated the structural, electronic, optical, and mechanical properties of Cs2Ag0.75X0.25BiCl6 (X = Na, K, Rb) double perovskites to assess their potential in underwater photovoltaic devices. The results demonstrate that Cs2Ag0.75X0.25BiCl6 double perovskites exhibit excellent photovoltaic performance, particularly with bandgaps between 1.8 and 2.3 eV, making them ideal for underwater photovoltaic applications. optical calculations show that these materials have a high light absorption coefficient, reaching up to 1.56×105 cm−1. Cs2Ag0.75Na0.25BiCl6, in particular, achieved a power conversion efficiency of 19.18 % with a bandgap of 1.83 eV, exhibiting high light absorption capacity. In terms of mechanical performance, Cs2Ag0.75Rb0.25BiCl6 displayed significant anisotropy, enhancing its mechanical stability under complex water flow conditions. In conclusion, the vacuum-ordered Cs2Ag0.75X0.25BiCl6 double perovskites exhibit excellent overall performance, providing important theoretical support for the development of efficient and reliable underwater photovoltaic materials. © 2025

关键词： Machinability

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Symmetry breaking of large-amplitude parametric oscillations in a few-layer graphene nanomechanical resonator

arXiv

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arXiv 2025年

作者： Yang, Chen Zhang, YuBin Lu, Heng Zhang, Ce Chen, FengNan Yan, Ying Xue, Fei Eichler, Alexander Moser, Joel School of Optoelectronic Science and Engineering Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou215006 China Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou215006 China School of Physics Hefei University of Technology Hefei230601 China Laboratory for Solid State Physics ETH Zürich Zürich8093 Switzerland

Graphene nanomechanical resonators are well suited for the study of parametric oscillations. Their large frequency tunability and their pronounced nonlinearities enable an efficient modulation of their resonant frequency. Here, we present measurements of the response of a few-layer graphene nanomechanical resonator driven by a large parametric pump at frequency 2ω and a weak external drive at ω, where ω is set near the mechanical resonant frequency ω0. The pump actuates the resonator beyond the threshold for large-amplitude parametric oscillations, while the drive breaks the symmetry of the parametric phase states. By increasing and decreasing a gate voltage to detune ω0 in the presence of the pump and the drive, we observe a double hysteresis in the response. The double hysteresis reveals the existence of two possible large-amplitude vibrational states whose phase difference is nearly π radians. We deterministically prepare the resonator in either one of these states by cycling the gate voltage. We measure the stationary occupation probabilities of the two states in the presence of a white Gaussian force noise, and find that they strongly depend on the amplitude and on the phase of the external drive. Parametric oscillations with broken phase symmetry hold promise as units of binary information. Their phase states can be mapped to biased bi-modal degrees of freedom, such as Ising spins in an external magnetic field. Our work invites future studies on coupled graphene parametric resonators whose phase states may be mapped to a system of Ising spins. © 2025, CC BY.

关键词： Natural frequencies

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Transient energy conversion in marine fuel cells: Multiphysics analysis of heat/mass transfer under realistic oceanic roll conditions

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Energy Conversion and Management 2025年 338卷

作者： Zheng Dong Yanjun Chen Deqiang He Guangxi Key Laboratory of Manufacturing System and Advanced Manufacturing Technology School of Mechanical Engineering Guangxi University Nanning 530004 China

Proton exchange membrane fuel cell (PEMFC) technology has emerged as a promising high-efficiency and zero-emission power solution for marine propulsion systems. While inertial forces induced by vessel motion are known to affect PEMFC performance, the specific impact mechanisms under rolling conditions remain unexplored. This study presents a systematic investigation of PEMFC dynamic characteristics under ocean rolling motion through a three-dimensional transient model integrating multiphysics coupling. The developed framework combines hydrodynamic analysis with dynamically updated rolling kinematics. The results show that the rolling motion leads to a maximum reduction of 9.89% in the fuel cell’s output power, a maximum fluctuation of 16.14% in the current density, and a 23.55% fluctuation in temperature. The magnitudes of these fluctuations escalate with decreasing rolling periods and increasing rolling angles. Additionally, higher operating voltages and lower operating pressures mitigate rolling-induced perturbations. Regarding the rolling effects, the streamwise inertial force emerges as a dominant factor. The rolling motion drives the redistribution of hydrogen and oxygen concentrations, modulates flow velocities, and alters pressure gradients within the flow channels. Consequently, these multiphysics interactions disrupt electrochemical kinetics, resulting in variability in hydrogen consumption (including efficiency losses) and thermal heterogeneity in the membrane.

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