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Trans-scale simulation reveals snowball effect in Li dendrite growth processes

Journal of Alloys and Compounds 2025年 1030卷

作者： Wen, Houguang Zhang, Maolin Wang, Saijing Zhao, Zhuo Wang, Yuan Yan, Yangxi Zhang, Dongyan Sun, Xiaofei School of Advanced Materials and Nanotechnology Xidian University Xi'an710071 China Shaanxi Key Laboratory of High-Orbits-Electron Materials and Protection Technology for Aerospace Xidian University Xi'an710071 China State Key Laboratory for Manufacturing System Engineering School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China

Li-based rechargeable batteries have played a critical role in the sustainable energy development strategy. However, the uncontrolled Li dendrites growth, which causes the poor cycling performance and safety concerns, has become their main drawback. Due to the sealed environment of the battery and the active reactivity of Li metal, in situ studies of Li dendrites are challenging. This work presents a trans-scale simulation method for modeling the Li dendrite growth process in Li-based batteries. First, a 2D Li metal battery model (2D LBM) was established to simulate Li nucleation sites at the nanoscale. Then, based on the growth process of nucleation sites in the 2D LBM, a phase-field model was established to simulate the Li dendrite growth process at the macroscopic scale. Furthermore, an in-situ observation experiment of the Li dendrite growth process was performed to illustrate the rationality of the simulation. This study shows the dynamic evolution of the micro-parameters inside the battery and reveals a snowball effect during the Li dendrite growth processes. This work provides a new perspective on understanding the mechanism of Li dendrite growth. © 2025 Elsevier B.V.

关键词： Lithium-ion batteries

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Data-Efficient Synchronous Machine Winding Short Circuit Faults Diagnosis Based on Frequency Response Analysis and Active Learning

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IEEE Sensors Journal 2025年第11期25卷 19804-19815页

作者： Chen, Yu Zhao, Zhongyong Liu, Jiangnan Wang, Wei Yao, Chenguo Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Wuhan430074 China Southwest University College of Engineering and Technology Chongqing400716 China Yibin Academy of Southwest University Sichuang64400 China Guangzhou Power Supply Bureau of Guangdong Power Grid Co. Ltd Guangzhou510620 China Chongqing University State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing400044 China

Winding short-circuit (SC) faults are a prevalent issue in synchronous machines, and the accurate and timely identification of these faults is critical for maintaining power system stability. Current methods for inspecting synchronous machine windings often rely on periodic inspections based on human expertise. Numerous studies have explored the application of deep learning (DL) models for detecting synchronous machine winding SC faults. However, these models often exhibit excessive complexity and overlook physical overhead, leading to inefficient utilization of computational power and data resources. To address these limitations, this study proposes a dual-channel deep learning (DL) model integrated with the active learning (AL) query strategy. In this study, winding SC faults are manually simulated on a 5 kVA synchronous machine, and corresponding frequency response analysis (FRA) data are recorded. Subsequently, the proposed method is validated on the test set and benchmarked against previous studies. Experimental results demonstrate that the proposed method significantly reduces the data annotation effort and accelerates model training to the order of seconds (under 5 seconds) while maintaining satisfactory accuracy (≥ 95%). Comparative experimental results further indicate that the proposed model, requiring only 1/20th of the labeled training samples used in previous studies, achieves a substantial reduction of approximately 99.8% in both model parameters and training time. © 2001-2012 IEEE.

关键词： Synchronous machinery

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Effect of the configuration and concentration of B-doping on the thermal properties and structural stability of graphene: A theoretical study

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Diamond and Related Materials 2025年 156卷

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

The thermal properties and structural stability of B-doped graphene were investigated by employing density functional theory (DFT), ab initio molecular dynamics (AIMD), and molecular dynamics (MD) simulations, with a focus on the effects of doping configuration and concentration. DFT calculations indicate that B-doping reduces the cohesive energy of graphene, consequently diminishing its structural stability. Among the three B double-doping configurations, only the para configuration exhibits a phonon dispersion without imaginary frequencies, whereas both meta and ortho configurations show imaginary frequencies, indicating structural instability. The AIMD results further demonstrate that B-doped graphene preferentially undergoes cleavage at B[sbnd]B bonds, leading to decreased structural stability. MD results show that B-doping significantly reduces the thermal conductivity of graphene. At a doping concentration is 0.6 %, the thermal conductivity of meta and para configurations decreases to 48.08 % and 54.6 % of that of the pristine graphene, respectively. The results of phonon properties show that B-doping reduces the phonon participation rate and induces strong phonon localization at the B-doped site. These results and conclusions will provide valuable theoretical insights for the thermal design of graphene-based semiconductor devices. © 2025 Elsevier B.V.

关键词： Temperature distribution

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Simultaneous enhancement of sensitivity, resonant frequency, and overload capability of piezoresistive accelerometers by heavily-doped fillet structures on sensing beams

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IEEE Sensors Journal 2025年第11期25卷 19138-19146页

作者： Xia, Yong Wang, Tao Lv, Yang Han, Xiangguang Yu, Mingzhi Tan, Renjie Huang, Mimi Jia, Chen Zhao, Libo Sun, Lin Yang, Ping Lu, Dejiang Xi'an Jiaotong University School of Mechanical Engineering State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies Xi'an710049 China Ningbo CRRC Times Transducer Technology Co. LTD Department of Basic Research and Development Ningbo315021 China Research Institute for Intelligent Sensing Technology and System School of Instrument Science and Technology State Key Laboratory for Manufacturing Systems Engineering State Industry-Education Integration Center for Medical Innovations International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies Xi'an Jiaotong University Xi'an710049 China Shandong Laboratory of Advanced Materials and green Manufacturing at Yantai Yantai264000 China

High sensitivity, high natural frequency, and high overload capability are desired for accelerometers used in industrial applications, but simultaneously enhancing all is challenging. Here, via designing novel heavily-doped fillet structures, we prove the sensitivity, resonant frequency, and overload capability can be simultaneously enhanced. The enhancements are attributed to regulations of stress concentration and effective sensing regions by the heavily-doped fillets. The sensors with and without fillets are designed, fabricated, packaged, and tested. The results show a sensitivity of 0.31±0.02 mV/g@5V, a natural frequency of 37.87±2.09 kHz, and an overload of 10040.17±531.76 g for sensors with 10-μm fillets, which are superior to 0.27±0.01 mV/g@5V, 34.13±0.90 kHz, and 7368.55±843.92 g for those no-fillet counterparts. Additionally, the developed sensor further exhibited feasibility in air-bearing vibration monitoring. The proposed design is envisioned to give insights into the novel designs of high-performance stress-based sensors, including accelerometers, pressure sensors, and strain gauges. © 2001-2012 IEEE.

关键词： Strain gages

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Kinematics and Dynamics Hessian Matrices of Manipulators Based on Screw Theory

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Chinese Journal of Mechanical Engineering 2015年第2期28卷 226-235页

作者： ZHAO Tieshi GENG Mingchao CHEN Yuhang LI Erwei YANG Jiantao Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University

The complexity of the kinematics and dynamics of a manipulator makes it necessary to simplify the modeling ***,the traditional representations cannot achieve this because of the absence of coordinate ***,the coordinate invariant method is an important research ***,the rigid-body acceleration,the time derivative of the twist,is proved to be a screw,and its physical meaning is *** on the twist and the rigid-body acceleration,the acceleration of the end-effector is expressed as a linear-bilinear form,and the kinematics Hessian matrix of the manipulator（represented by Lie bracket）is ***,Newton-Euler＇s equation is rewritten as a linear-bilinear form,from which the dynamics Hessian matrix of a rigid body is *** formulae and the dynamics Hessian matrix are proved to be coordinate *** to the principle of virtual work,the dynamics Hessian matrix of the parallel manipulator is gotten and the detailed dynamic model is *** index of dynamical coupling based on dynamics Hessian matrix is *** the end,a foldable parallel manipulator is taken as an example to validate the deduced kinematics and dynamics *** screw theory based method can simplify the kinematics and dynamics of a manipulator,also the corresponding dynamics Hessian matrix can be used to evaluate the dynamical coupling of a manipulator.

关键词： kinematics dynamics Hessian matrix parallel manipulator screw theory

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Ultra-fast, high-power MUTC Photodiodes with bandwidth-efficiency product over 130 GHz × 100%

arXiv

引用

arXiv 2025年

作者： Li, Linze Long, Tianyu Yang, Xiongwei Zhang, Zhouze Wang, Luyu Wang, Jingyi Wang, Mingxu Lu, Juanjuan Yu, Jianjun Chen, Baile School of Information Science and Technology ShanghaiTech University Shanghai201210 China Fastphide Photonics Shanghai201210 China China State Key Laboratory of ASIC and System Fudan University Shanghai200433 China Key Laboratory for Information Science of Electromagnetic Waves Shanghai Institute for Advanced Communication and Data Science Fudan University Shanghai200433 China School of Information Science and Technology Fudan University Shanghai200433 China

The accelerating demand for wireless communication necessitates wideband, energy-efficient photonic sub-terahertz (sub- THz) sources to enable ultra-fast data transfer. However, as critical components for THz photonic mixing, photodiodes (PDs) face a fundamental trade-off between quantum efficiency and bandwidth, presenting a major obstacle to achieving high-speed performance with high optoelectronic conversion efficiency. Here, we overcome this challenge by demonstrating an InP-based, waveguide-integrated modified unitraveling carrier photodiode (MUTC-PD) with a terahertz bandwidth exceeding 200 GHz and a bandwidth-efficiency product (BEP) surpassing 130 GHz × 100%. Through the integration of a spot-size converter (SSC) to enhance external responsivity, alongside optimized electric field distribution, balanced carrier transport, and minimized parasitic capacitance, the device achieves a 3-dB bandwidth of 206 GHz and an external responsivity of 0.8 A/W, setting a new benchmark for BEP. Packaged with WR-5.1 waveguide output, it delivers radiofrequency (RF) power exceeding -5 dBm across the 127-185 GHz frequency range. As a proof of concept, we achieved a wireless transmission of 54 meters with a single-line rate of up to 120 Gbps, leveraging photonics-aided technology without requiring a low-noise amplifier (LNA). This work establishes a pathway to significantly enhance optical power budgets and reduce energy consumption, presenting a transformative step toward high-bandwidth, high-efficiency sub-THz communication systems and next-generation wireless networks. Copyright © 2025, The Authors. All rights reserved.

关键词： Budget control

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Long-Lived Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence for Optoelectronic Devices

SSRN

引用

SSRN 2025年

作者： Wang, Ping Wang, Hanyu Long, Chunye Guan, Yan Wang, Yang Wu, Chengheng Wang, Pu Wang, Fuzhi Xie, He-Lou Key Lab of Environment-friendly Chemistry and Application in Ministry of Education Key Laboratory of Polymeric Materials and Application Technology of Hunan Province Key Laboratory of Advanced Functional Polymer Materials of Colleges Universities of Hunan Province College of Chemistry Xiangtan University Hunan Province Xiangtan411105 China Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of Education Center for Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing100871 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of New Energy North China Electric Power University Beijing102206 China

Organic thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) materials have merited enormous application prospects in organic optoelectronics. In spite of this, long-lived TADF and RTP dual emissions based on single polymers still face great challenge. In this work, we develop a monomer (CzBT) with twisted electron donating carbazole and electron withdrawing benzothiadiazole (D-A) structure and then copolymerize it with N-isopropylacrylamide (NIPAM) to achieve TADF and RTP dual-emission polymers (NP1-50~NP1-1000). They not only exhibit high efficiency (20%) and long-lived (268 ms) TADF emission, but also present red RTP emission with lifetime reaching 240 ms. Theoretical calculations confirm that the introduction of twisted D-A structure and heteroatoms can not only provide appropriate ΔEST (0.21 eV) between the singlet and triplet states to promote long-lived TADF, but also enhance spin orbital coupling for RTP emission. High performance active optical waveguide with quite low optical loss coefficient of 0.097 dB/mm was obtained for NP1-50 fiber. When applied to solution-processable organic light emitting diodes (OLED) devices, it yields excellent current efficiency of 62.7 cd/A with small efficiency roll-off and maximum luminance of 90858 cd/m2. This class of polymers pave the road for high efficiency optoelectronic devices. © 2025, The Authors. All rights reserved.

关键词： Fluorescence

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Electric Field Manipulation of Rydberg states for Very Low Frequency Fields Detection

arXiv

引用

arXiv 2025年

作者： Chen, Minze Feng, Haonan Gao, Ge Zhu, Zhiao Li, Zhongxiang Wu, Zhonghuai Xiao, Wei Dai, Weidong Peng, Peng Zheng, Dezhi State Key Laboratory of Environment Characteristics and Effects for Near-Space Beijing Institute of Technology Beijing100081 China National Key Laboratory of Science and Technology on Space-Born Intelligent Information Processing Beijing100081 China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing100081 China Jiaxing314019 China Zhuhai519088 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China Taizhou Meteorological Bureau Taizhou318000 China Chongqing Caeri Robot Technology Co. Ltd. Chongqing400722 China

The very low frequency(VLF) band is widely used in submarine communication and geophysical exploration for its strong penetration and long-distance propagation. This paper theoretically and experimentally investigates Rydberg EIT in 133Cs vapor under VLF and DC fields. A model is established to describe the EIT spectral response under dual-field conditions, with theoretical predictions showing agreement with experimental results. We propose a novel calibration-free method to measure VLF electric fields, bypassing traditional Stark shift measurements. This method detects additional splitting intervals of Stark sublevels, separated from the degenerate energy level under a DC field. This phenomenon arises from the averaging effect of sublevel sinusoidal oscillations in the spectrum induced by the VLF field. The splitting interval is proportionally dependent on the VLF field amplitude. The VLF electric field sensor is enhanced by increasing the strength of the DC field, extending the traceable measurement limit for weak VLF electric fields by more than an order of magnitude. This work highlights the potential for precise VLF electric field measurements, significantly advancing the calibration-free detection capabilities of Rydberg atom sensors for low-frequency applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Rydberg states

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Stacking, Strain-Engineering Induced Altermagnetism, Multipiezo Effect, and Topological state in Two-Dimensional Materials

arXiv

引用

arXiv 2025年

作者： Xun, Wei Liu, Xin Zhang, Youdong Wu, Yin-Zhong Li, Ping Jiangsu Engineering Research Center for Design and Application of Intelligent Detection Equipment 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, as a newly identified form of unconventional antiferromagnetism, 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, the rare attention has been paid to the relationship between stacking, strain and altermagnet, multipiezo effect and topological state. Here, we propose a mechanism to realize the altermagnet, multipiezo effect, and topological state in two-dimensional 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, MzUt, or MzPTt 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 Jauns 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, CC BY.

关键词： Antiferromagnetism

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Kinetostatics Analysis of a Novel 6-DOF Parallel Manipulator with Three Planar Limbs and Equipped with Three Fingers

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 919-927页

作者： LU Yi LI Xuepeng College of Mechanical Engineering Yanshan University Key Laboratory of Parallel Robot and Mechatronic System of Hebei Province Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education

It is significant to develop a robot hand with high rigidity by a 6-DOF parallel manipulator（PM）.However,the existing6-DOF PMs include spherical joint which has less capability of pulling force bearing,less rotation range and lower precision under alternately heavy loads.A novel 6-DOF PM with three planar limbs and equipped with three fingers is proposed and its kinematics and statics are analyzed systematically.A 3-dimension simulation mechanism of the proposed manipulator is constructed and its structure characteristics is *** kinematics formulae for solving the displacement,velocity,acceleration of the platform,the active legs and the fingers are *** statics formulae are derived for solving the active forces of PM and the finger *** analytic example is given for solving the kinematics and statics of proposed manipulator and the analytic solved results are verified by the simulation *** is proved from the error analysis of analytic solutions and simulation solutions that the derived analytic formulae are correct and provide the theoretical and technical foundations for its manufacturing,control and application.

关键词： parallel manipulator planar limbs finger kinematics statics

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