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A fast fully coupled FEM/BEM method for structural-acoustic interaction problems with a uniformly moving source

Engineering Analysis with Boundary Elements 2025年 177卷

作者： Sun, Ruihua Wu, Haijun Wang, Siyuan Gou, Yinong Jiang, Weikang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China Institute of Vibration Shock and Noise Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong University Shanghai China

When a structure moves uniformly at high-speed, the structural-acoustic coupling significant alters the acoustic field distribution compared to conditions without coupling. We propose a hybrid numerical method combining the finite element method (FEM) for structural vibration and the convective boundary element method (BEM) for sound propagation in uniform flow to predict the acoustic field of a uniformly moving body. We introduce the acoustic-analogy Lorentz (a-a Lorentz) transformation to accelerate the convective BEM. To establish the structural-acoustic coupling condition, we derive a mapping method for different physical fields and spacetimes based on the time and space transformations of the a-a Lorentz transformations. A fully coupled solution scheme based on the fast multipole method (FMM) has been developed. By integrating the FEM matrix into the boundary element equation, we eliminate structural degrees of freedom and address the ill-conditioned issue of the direct coupling matrix. Additionally, the FMM efficiently handles large-scale problems. We construct a semi-analytical model to verify the proposed method's correctness and efficiency. The impact of varying Mach numbers and structural elasticity modulus on the coupling effect is analyzed indicating that coupling analysis is essential under high-speed conditions. A full-fuselage model is computed to validate the method's efficiency for large-scale problems. © 2025

关键词： Boundary element method

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pH-driven interfacial bond dynamics enable high-efficiency low-damage polishing of fused silica with CeO2 based slurries

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Journal of Materials Processing Technology 2025年 341卷

作者： Li, Fukun Bai, Yang Hu, HaiXiang Qiao, Guanbo Li, Lingzhong Zhang, Feng Zhang, Xuejun Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun130033 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Advanced Manufacturing for Optical System Jilin Changchun130033 China

Achieving atomic-level surface integrity while maintaining a high material removal rate (MRR) remains a fundamental challenge in the polishing of fused silica due to its high hardness and brittleness. This study establishes a novel mechanistic framework for understanding how pH-driven interfacial bond dynamics govern chemo-mechanical polishing processes. By integrating multiscale experimental characterization (XPS, FTIR, Raman spectroscopy) with ReaxFF molecular dynamics simulations, we demonstrate for the first time that the dynamic equilibrium between the formation and rupture of Ce–O–Si interfacial bonds directly control removal efficiency and surface quality. Alkaline conditions enhance OH– activity, facilitating Si–O bond hydrolysis and stable Ce–O–Si linkage formation, resulting in the highest MRR (397.6 nm/min). Acidic environments promote citrate-mediated Ce3+ complexation and nanocluster dispersion, enabling a rolling mechanism that achieves ultra-smooth surfaces (Sq = 0.086 nm). In contrast, neutral pH conditions suffer from PEG adsorption blocking active sites, leading to a 62 % reduction in MRR relative to alkaline systems. A 12.2-fold increase in MRR compared to SiO2 abrasives (32.67 nm/min) confirms that chemical interfacial dynamics, rather than mechanical abrasion alone, are critical to material removal. This fundamental advancement provides a broadly generalizable theoretical basis for designing efficient, low-damage precision polishing processes across oxide-based optical materials and beyond. © 2025

关键词： Fused silica

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Selection for Schottky Barrier Diodes with Various On-Resistance in Full-SiC Voltage Source Converters

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IEEE Transactions on Industry Applications 2025年

作者： Chen, Yuzhi Li, Chi Liu, Jianwei Wu, Yifan Liu, Zicheng Zheng, Zedong Tsinghua University State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Beijing 100084 China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan 430074 China

In Silicon Carbide based voltage source converters (VSCs), pairing Schottky barrier diodes (SBDs) presents trade-offs. While SBDs reduce the freewheeling loss and mitigate the adverse effects of bipolar conduction, their junction capacitance also contributes to increased switching loss. This paper proposes a systematic selection strategy for SBDs aimed at enhancing converter efficiency, using on-resistance as the design variable. A three-phase VSC with 1.2 kV MOSFETs and four sets of 1.2 kV SBDs is demonstrated as the case study. The static and switching characteristics for MOSFET/SBD pair are measured and analyzed over a wide temperature range. VSC efficiency is evaluated in both inverter and rectifier modes under different operating conditions. It appears that VSC using SBDs with 126% of the MOSFETs' resistance exhibits an overall superior performance. A 4 kW full-SiC VSC prototype is developed to validate the proposed selection strategy. Compared to other SBDs, using the recommended selection enhances VSC efficiency by up to 2% (± 0.5%) under light loads while maintaining high performance under medium and heavy loads. Compared to freewheeling by the body diode, using the recommended selection enhances VSC efficiency by an average of 0.4% (± 0.1%) across nearly the entire load range. © 1972-2012 IEEE.

关键词： efficiency on-resistance Schottky barrier diodes selection strategy SiC MOSFETs voltage source converter

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Designing Large-Element-Spacing Arrays for Diverse Modular Subarrays Through Iterative Convex Relaxation Optimization

Designing Large-Element-Spacing Arrays for Diverse Modular S...

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European Conference on Antennas and Propagation, EuCAP

作者： Gongqing Yang Hui Zeng Zhenhai Xu Wei Dong The State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System National University of Defense Technology Changsha China College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha China

ISBN: (数字)9788831299107

ISBN: (纸本)9798350366327

This paper introduces a novel modular subarray design method that employs large-element-spacing modular subarrays. By strategically designing the structure and placement of the basic modular units, the method effectively suppresses grating lobes caused by large inter-element spacings (exceeding half a wavelength). Traditional large-element-spacing array designs are always non-modular, leading to inconvenience in design, manufacturing, assembly, and maintenance. The proposed modular design simplifies production and assembly while maintaining excellent pattern performance. The design outcomes are obtained through Iterative Convex Relaxation Optimization. Numerical simulations and analyses confirm the efficacy of the proposed design.

关键词： Optimization models Design methodology Europe Production Numerical simulation Iterative algorithms Maintenance Gratings Optimization Assembly

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Structural, electrical, phonon, and optical properties of 2D metals: A DFT calculation

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Journal of Applied Physics 2025年第16期137卷

作者： Li, Dongbo Wu, Long Huang, Kaifeng Yu, Liang Wang, Haini Yu, Yaqi Da, Liangguo Tang, Yunqing School of Mechanical and Electrical Engineering Huainan Normal University Huainan232038 China Human-Computer Collaborative Robot Joint Laboratory of Anhui Province Huainan232038 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 Ministry of Education School of Mechanical Engineering Shandong University Jinan250061 China

We investigated the structure, electrical, phonon, and optical properties of 2D metals (goldene, silverene, and copperene) by density functional theory. The results of the electronic band structure reveal that goldene and copperene exhibit metallic characteristics, whereas silverene demonstrates semimetallic properties. The results of the electronic density of states show that the s-d-orbital coupling is the strongest in goldene, followed by silverene, and the weakest in copperene. The s-d-orbital coupling has the effect of softening phonons and reducing lattice thermal conductivity. Phonon property analysis demonstrates that there are no imaginary frequencies in the phonon dispersion curves of goldene, silverene, and copperene, indicating their dynamic stability. The results of optical properties show that goldene and copperene exhibit high absorptivity, reflectivity, conductivity, and refractive index in the low-frequency region, and the optical properties of the three 2D metals gradually converge to the same as the frequency increases. This research provides a theoretical foundation and guidance for exploring novel two-dimensional metal materials. © 2025 Author(s).

关键词： Density (optical)

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Pulsating Torque Suppression of Flux Reversal Machines Based on Specific Harmonic Contributions of Rotor Permeance and PM MMF

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IEEE Transactions on Industry Applications 2025年

作者： Li, Junzhou Gao, Yuting Zhang, Chaofeng Zha, Xiaoming Qu, Ronghai Wuhan University School of Electrical Engineering and Automation Wuhan430072 China Key Laboratory of Integrated Energy Power Equipment and System Security Hubei430206 China State Grid Henan Electric Power Research Institute Zhengzhou450052 China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

Flux reversal machines (FRMs) exhibit high torque density, but also significant pulsating torque, including cogging torque and torque ripple. Traditional methods fail to separate the harmonics that affect torque density and pulsating torque, leading to a degradation of torque density when reducing pulsating torque. Therefore, to maintain torque density and simultaneously reduce pulsating torque, this paper proposes a novel FRM configuration incorporating shape designs for the rotor and permanent magnets (PMs). First, the key generation mechanisms of cogging torque, average torque, and torque ripple are thoroughly examined, with analytical expressions derived to classify the torque contributions of all air-gap magnetic field harmonics into negative-effect and positive-effect components. Further, the rotor and PM shapes are designed to enhance the positive-effect components and reduce the negative-effect ones of the air-gap permeance and magnetomotive force (MMF). The impacts of geometric parameters are evaluated by using a sensitivity-based hierarchical optimization approach. Then, the proposed FRM is comprehensively compared with a conventional FRM in terms of back-electromotive force (EMF), cogging torque, average torque, torque ripple, efficiency, etc. The results indicate that the proposed machine configuration achieves reductions in cogging torque and torque ripple by 90% and 86.8%, respectively, while maintaining consistent average torque. Finally, a 12-slot/10-pole FRM prototype was built and tested to validate the effectiveness of the proposed machine topology. © 1972-2012 IEEE.

关键词： Permanent magnets

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Stacking-, strain-engineering induced altermagnetism, multipiezo effect, and topological state in two-dimensional materials

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Applied Physics Letters 2025年第16期126卷

作者： Xun, Wei Liu, Xin Zhang, Youdong Wu, Yin-Zhong Li, Ping School of Electronic Engineering Jiangsu Vocational College of Electronics and Information Huaian223003 China School of Physical Science and Technology Suzhou University of Science and Technology Suzhou215009 China State Key Laboratory for Mechanical Behavior of Materials Center for Spintronics and Quantum System School of Materials Science and Engineering Xi'an Jiaotong University Shaanxi Xi'an710049 China State Key Laboratory for Surface Physics Department of Physics Fudan University Shanghai200433 China State Key Laboratory of Silicon and Advanced Semiconductor Materials Zhejiang University Hangzhou310027 China

Altermagnetism, a recently identified form of unconventional antiferromagnetism (AFM), enables the removal of spin degeneracy in the absence of net magnetization that provides a platform for the low power consumption and ultra-fast device applications. However, a little attention has been paid to the relationship between stacking, strain, and altermagnet, the multipiezo effect, and the topological state. Here, we propose a mechanism to realize the altermagnet, the multipiezo effect, and the topological state in two-dimensional (2D) materials by the stacking and strain engineering. Based on the analysis of symmetry, we find that the spin splitting feature related to the Ut, PTt, M z U t , or M z PTt symmetries in altermagnet multilayers. In addition, we find that the stacking engineering can effectively realize the transform from antiferromagnetism to altermagnetism and semiconductor to metal for the Janus bilayer V2SeTeO. More interestingly, the strain not only induces an intriguing multipiezo effect, encompassing the piezovalley, piezomagnetism, and piezoelectric, but also achieves the abundant topological phase. Our findings offer a generalized direction for manipulating the spin splitting, valley polarization, and topological states, promoting practical application of valleytronic and spintronic devices based on two-dimensional altermagnets. © 2025 Author(s).

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Aeroengine remaining useful life prediction via integrating enhanced inverted transformer and spatiotemporal graph learning

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ISA Transactions 2025年

作者： Sun, Shilong Ding, Hao Zhao, Zida Zhou, Yu Wang, Dong Xu, Wenfu School of Robotics and Advanced Manufacturing College of Artificial Intelligence Harbin Institute of Technology Shenzhen China Guangdong Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics Shenzhen China College of Computer Science and Software Engineering Shenzhen University Shenzhen518060 China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai200240 China

Accurate prediction of aeroengine Remaining Useful Life (RUL) is critical for ensuring flight safety, minimizing maintenance costs, and improving operational efficiency. This study proposes a novel model, the Fourier-Enhanced Inverted Transformer with Graph-Augmented Spatiotemporal Modeling (FIT-GSTM), to enhance RUL prediction performance. FIT-GSTM combines an inverted Transformer with a Spatiotemporal Graph Convolutional Network (STGCN) to effectively capture global spatiotemporal dependencies across multi-sensor data. To further enrich feature representation, the model incorporates Fast Fourier Transform (FFT) to extract frequency-domain information and fuses it with time-domain features, enhancing robustness to noise. Additionally, the integration of Memory Tokens and Reversible Instance Normalization (RevIN) strengthens the model's ability to retain long-term dependencies and adapt to heterogeneous data distributions. Experimental evaluations on the C-MAPSS dataset demonstrate that FIT-GSTM achieves superior RUL prediction accuracy and generalization compared to existing methods, highlighting its potential for real-world deployment in aeroengine health management. © 2025 ISA

关键词： Fast Fourier transforms

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Modified Kelvin-Voigt fractional derivative model for viscoelasticity measurement in optical coherence elastography

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Chinese Optics Letters 2025年第1期23卷 93-101页

作者： Chenming Yang Zhongliang Li Nan Nan Teng Liu Yaoli Luo Xiangzhao Wang Advanced Light Source and System R&D Center Department of Advanced Optical and Microelectronic EquipmentShanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China

Optical coherence elastography(OCE)can quantitatively obtain the viscoelasticity of tissues using rheological models and is widely applied to the clinical diagnosis of ***,commonly used rheological models in OCE do not account for the distinctive dependence of high-frequency storage and loss moduli on frequency in tissues,which results in the rheological models failing to accurately measure the viscoelastic properties of *** this paper,a modified Kelvin-Voigt fractional derivative model is presented based on the power-law behavior of soft tissues and the dependence of high-frequency complex shear modulus on frequency in living *** the rheometer and OCE tests,the modified model can provide the prediction of the power-law relationship between the low-frequency shear viscosity and frequency;compared with the Kelvin-Voigt and Kelvin-Voigt fractional derivative models,the modified model has a higher goodness-of-fit(accuracy>96%)for the high-frequency storage moduli of gelatin ***,the proposed model can reduce the root mean square error of fit by approximately 83%for the high-frequency(1–128 kHz)storage modulus of the polydimethylsiloxane phantoms obtained from publicly available ***,the modified model accurately predicts the mechanical properties of biomimetic materials over a wide frequency range,with the potential to more accurately reflect pathological changes in tissues.

关键词： optical coherence tomography optical coherence elastography viscoelasticity rheological model

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A phenotype-independent "label-capture-release" process for isolating viable circulating tumor cells in real-time drug susceptibility testing

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Innovation 2025年第5期6卷 100805页

作者： Lao, Zhiqi Ren, Xiaoxue Zhuang, Dehua Xie, Lingxia Zhang, Yucong Li, Wei Chen, Yue Li, Penghui Tong, Liping Chu, Paul K. Wang, Huaiyu Institute of Biomedicine and Biotechnology Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China Shenzhen518020 China Departments of Physics Materials Science and Engineering and Biomedical Engineering City University of Hong Kong Hong Kong SAR999077 China Key Laboratory of Biomedical Imaging Science and System Chinese Academy of Sciences Shenzhen518055 China State Key Laboratory of Biomedical Imaging Science and System Shenzhen518055 China

Although various strategies have been proposed for enrichment of circulating tumor cells (CTCs), the clinical outcomes of CTC detection are far from satisfactory. The prevailing methodologies for CTC detection are generally oriented toward naturally occurring targets;however, misdetection and interference are prevalent due to the diverse phenotypes and subpopulations of CTCs, which are highly heterogeneous. Here, a CTC isolation system based on the "label-capture-release" process is demonstrated for the precise and highly efficient enrichment of CTCs from clinical blood samples. On the basis of the abnormal glycometabolism of tumor cells, the surface of CTCs can be decorated with artificial azido groups. By utilizing bio-orthogonal plates designed with dibenzocyclooctane (DBCO) and disulfide groups, with the aid of anti-fouling effects, CTCs labeled with azido groups can be captured through a copper-free click reaction and subsequently released via disulfide reduction. The technique has been shown to label tumor cells with the epithelial cell adhesion molecule (EpCAM)+ and EpCAM− phenotypes in both adherent and suspended states. Moreover, it effectively isolates all epithelial, interstitial, and hybrid phenotypes of CTCs from clinical blood samples collected from dozens of patients across more than 10 cancer types. Compared to the clinically approved CTC detection system, our strategy demonstrates superior performance from the perspective of broad-spectrum and accurate recognition of heterogeneous CTCs. More importantly, most of the captured CTCs can be released with the retention of living activity, making this technique well suited for downstream applications such as drug susceptibility tests involving viable CTCs. © 2025 The Author(s)

关键词： Blood

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