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Elastic wave propagation and attenuation characteristics of roof fracture source

Geomechanics and Engineering 2025年第4期40卷 295-305页

作者： Zhang, Peng-Fei Zhao, Tong-Bin Gong, Xu-Fei Tan, Yan Guo, Chuan-Qing College of Energy and Mining Engineering Shandong University of Science and Technology Qingdao266590 China State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and Technology Qingdao266590 China Shandong Key Laboratory of Intelligent Prevention and Control of Dynamic Disaster in Deep Mines Shandong University of Science and Technology Qingdao266590 China Energy Group Co. Ltd. Jining No.2 Coal Mine Jining272012 China

Abstract. The propagation attenuation law of elastic waves generated by rock mass fractures in strata is of great significance in explaining engineering problems, such as rock bursts. In this study, a wave velocity model was established based on the actual stratum conditions of the Jining No.2 coal mine in China. The propagation process of different types of elastic waves is simulated using the elastic wave equation and finite difference method. The attenuation coefficients of various elastic wave parameters propagating at different positions were calculated. Based on the calculated results, an attenuation equation for the elastic wave energy is proposed. The results show that the propagation of S-waves and P-waves in strata is similar to each other, and wave pattern transformation occurs at the interface of the strata. The magmatic rocks played a role in channeling and reflecting elastic wave propagation, leading to the occurrence of low-energy aftershocks in the coal seams. The peak displacement, peak stress, and energy density of the elastic wave that propagated to the coal seam after the siltstone layer fracture of the roof of the 3down coal seam decreased to 28%, 25%, and 9% of the source, respectively. The attenuation of elastic wave energy is highly correlated with the propagation distance, and the attenuation equation can be represented as an exponential function. These results are of great significance for revealing the propagation attenuation process of elastic waves in the stratum. © 2025 Techno-Press, Ltd.

关键词： Exponential functions

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NO_(2) gas sensor with high selectivity and fast response based on Pt-loaded nanoporous GaN

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International Journal of Minerals,Metallurgy and Materials 2025年第4期32卷 964-972页

作者： Dan Han Xiaoru Liu Donghui Li Jiexu Shi Yu Wang Yuxuan Wang Hongtao Wang Shengbo Sang Shanxi Key Laboratory of Micro/Nano Sensors&Artificial Intelligence Perception College of Integrated CircuitsTaiyuan University of TechnologyTaiyuan030024China Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education Taiyuan University of TechnologyTaiyuan 030024China Shanxi Research Institute of 6D Artificial Intelligence Biomedical Science Taiyuan 030032China

In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with the catalysis of *** gas sensor gained excellent sensitivity to NO_(2) at a concentration range of 200 ppm to 100 ppb,benefiting from the loading of Pt nanoparticles,and exhibited a short response time(22 s)and recovery time(170 s)to 100 ppm of NO_(2) at room temperature with excellent selectivity to NO_(2) compared with other *** phenomenon was attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt,which not only provided more electrons for the adsorption of NO_(2) molecules but also occupied effective sites,causing poor sites for other *** low detection limit of Pt/NP-GaN was 100 ppb,and the gas sensor still had a fast response 70 d after ***,the gas-sensing mechanism of the gas sensor was further elaborated to determine the reason leading to its improved *** significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials,leading to the improvement of the gas properties of gas sensors.

关键词： nanoporous gallium nitride platinum nitrogen dioxide gas sensor

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Dynamic and Static Simulation Analysis and Optimisation Design of DC220V Permanent Magnetic Detacher 7

Dynamic and Static Simulation Analysis and Optimisation Desi...

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7th International Conference on Electric Power Equipment - Switching technology, ICEPE-ST 2024

作者： Dai, Dongyun Zhuo, Kaicai You, Yimin Wang, Xiankun Wang, Xu School of Electrical Engineering and Automation Xiamen University of Technology Xiamen Key Laboratory of Frontier Electric Power Equipment and Intelligent Control Xiamen China

ISBN: (纸本)9798350388947

In order to solve the problems of too long action time and low action reliability of electromagnetic type tripping release of vacuum circuit breaker. This paper researches and designs a kind of rated control voltage is DC220V, tripping action time is less than 15ms, tripping current is less than 2A permanent magnetic detacher. Firstly, Solidworks software is applied to establish the 3D model of the permanent magnet detacher and simplify the model. Considering the key components of the permanent magnet detacher, Maxwell simulation software is applied to analyze the dynamic and static simulation of the permanent magnet detacher, which finally meets the design requirements and is verified by tests. The test results show that the designed permanent magnetic detacher can shorten the breaking time of vacuum circuit breaker from the original 30ms to less than 15ms under its rated control voltage. The research results of this thesis can provide guidance for the simulation and optimization design of permanent magnet detacher, which has certain engineering application value. © 2024 IEEE.

关键词： Permanent magnets

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Research on a Permanent Magnet Trip Device for DC Miniature Circuit Breakers 7

Research on a Permanent Magnet Trip Device for DC Miniature ...

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7th International Conference on Electric Power Equipment - Switching technology, ICEPE-ST 2024

作者： You, Yimin Pan, Yiwei Dai, Dongyun Wang, Lizhi School of Electrical Engineering and Automation Xiamen University of Technology Xiamen Key Laboratory of Frontier Electric Power Equipment and Intelligent Control Xiamen China

ISBN: (纸本)9798350388947

The article investigates the structure of a permanent magnet tripping device used in non-polarized DC miniature circuit breakers, proposing a permanent magnet arrangement relative to the moving iron core as an alternative to the traditional built-in spring design. Dynamic and static characteristics of this permanent magnet tripping device were calculated using simulation software and compared with those of a traditional tripping device. The results indicate that when a short-circuit current occurs, the permanent magnet tripping device can execute tripping actions more accurately and rapidly compared to the traditional design, ensuring efficient and stable operation of the miniature circuit breaker. Subsequent transient tripping experiments conducted on circuit breakers equipped with both types of tripping devices validated the accuracy of these findings. © 2024 IEEE.

关键词： Permanent magnets

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Research on gesture recognition method based on PSO optimized LSTM for surface muscle signals 6

Research on gesture recognition method based on PSO optimize...

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6th Asia Symposium on Image Processing, ASIP 2024

作者： Dai, Jianyi Lu, Guangda Qin, Zhuanpin Guo, Xiaoqian Liu, Xinlin Yin, Qianhan Tianjin University of Technology and Education Tianjin Key Laboratory of Information Sensing and Intelligent Control Hexi District No. 1310 Tianjin300222 China

ISBN: (纸本)9798350376159

(sEMG) Surface EMG signals can quickly and accurately reflect the movement intention of human body, gesture recognition by sEMG has been widely studied in the field of human-robot interaction in rehabilitation robots, in order to improve the accuracy of gesture recognition. A gesture recognition method based on PSO optimised LSTM for surface muscle signals is investigated. Firstly, the S_Dbw method is used to evaluate the clustering validity of the time domain features of the surface EMG signals, and the feature (MAV)combination of absolute mean +(RMS)root mean square (RMS)+ (VAR) variance is selected as the feature space and input to the model of the depth algorithm. Secondly, in order to solve the problem of cumbersome parameter debugging and low accuracy of (LSTM)Long Short-Term Memory neural network (LSTM), Particle Swarm Optimization-Long Short-Term Memory PSO-LSTM algorithm is proposed and combined with convolutional neural network (convolutional neural network, CNN) and Long Short-Term Memory LSTM. The experimental results show that the PSO-LSTM model has an average recognition accuracy of 94.1%, which is 8.3% and 4.7% higher than the CNN and LSTM, and the average training time of the LSTM model is reduced by 35.52s compared to the LSTM. Therefore, it is advantageous to use PSO-LSTM model in gesture sEMG signal recognition and classification. © 2024 IEEE.

关键词： Convolutional neural networks

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Research on human movements push up counter based on media-pipe artificial intelligence 6

Research on human movements push up counter based on media-p...

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6th Asia Symposium on Image Processing, ASIP 2024

作者： Saido, Balde Lu, Guangda Qin, Zhuanpin Yin, Xianhan Dai, Jianyi Guo, Xiaoqian Tianjin University of Technology and Education Tianjin Key Laboratory of Information Sensing and Intelligent Control Hexi District No. 1310 Tianjin300222 China

ISBN: (纸本)9798350376159

This paper introduces a project that integrates pose estimation and deep learning to evaluate exercise performance and provide real-time feedback on repetition counts during workouts. Using machine learning in the fitness sector, the study focuses on accurately tracking and counting exercise repetitions, which is beneficial for physical education and competitive fitness events. The paper presents a novel real-time push-up counting method based on 2D video analysis, utilizing Media-pipe for precise pose estimation and motion analysis. By following the push-up guidelines set by the National Academy of Sports Medicine, the method differentiates between correct and incorrect push-up forms. The experimental results show that the proposed method achieves an accuracy of 90.00%, precision of 91.67%, recall of 91.67%, and an F1-Score of 91.66%. The integration of pose estimation and deep learning in the fitness industry offers new opportunities for improving workout monitoring, ensuring proper form, and optimizing fitness outcomes for individuals of different fitness levels. © 2024 IEEE.

关键词： Sports medicine

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Fractional core-based collapse mechanism and structural optimization in complex systems

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Science China(Information Sciences) 2023年第9期66卷 168-183页

作者： Shubin SI Changchun LV Zhiqiang CAI Dongli DUAN Jurgen KURTHS Zhen WANG School of Mechanical Engineering Northwestern Polytechnical University Key Laboratory of Industrial Engineering and Intelligent Manufacturing(Ministry of Industry and Information Technology) School of Information and Control Engineering Xi'an University of Architecture and Technology Instiute of Physics Humboldt-University Potsdam Institute for Climate Impact Research

Catastrophic and major disasters in real-world systems ranging from financial markets and ecosystems, often show generic early-warning signals that may indicate a collapse. Hence, understanding the collapse mechanism of a complex network and predicting its process are of uttermost importance. However, these challenges are often hindered by the extremely high dimensionality of the underlying *** present here the concept of the fractional core(F-core) that considers the contribution of the network topology and dynamics to systematically analyze the collapse process in such networks, and encompass a broad range of dynamical systems, from mutualistic ecosystems to regulatory dynamics. We offer testable predictions on the tipping point, and, in particular, prove that the extinction of the maximum F-core of a network is an efficient indicator of whether a system completely collapses. The results show that the death of species or cells in a low-order F-core may improve the average density and have little influence on the tipping point. Generally, the principle of the F-core demonstrates how complex systems collapse and opens an innovative optimization strategy to uncover the optimal structure of systems.

关键词： collapse mechanism tipping point structural optimization complex systems phase transition

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Structural Optimization of Shielding Cover For 24kV and 72.5kV Vacuum Interrupters 7

Structural Optimization of Shielding Cover For 24kV and 72.5...

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7th International Conference on Electric Power Equipment - Switching technology, ICEPE-ST 2024

作者： Sang, Zhongqing Zhang, Yan You, Yimin Dai, Dongyun Tu, Yuanting Wang, Xu School of Electrical Engineering and Automation Xiamen University of Technology Xiamen Key Laboratory of Frontier Electric Power Equipment and Intelligent Control Xiamen China

ISBN: (纸本)9798350388947

Vacuum interrupters are widely used in power transmission and distribution systems, vacuum interrupters factory test inspection, some products will appear insulation breakdown phenomenon, resulting in a decline in the overall yield rate. Therefore, this paper is aimed at improving the insulation performance of vacuum interrupter this problem to carry out in-depth research. This paper adopts the finite element analysis method to carry out electric field simulation calculations, through the establishment of a 3D model of the 24kV spiral groove contact vacuum interrupter chamber, insulation optimization of the internal structure of the vacuum interrupter chamber, it can be obtained that the vacuum interrupter chamber overall electric field strength with the reduction of the length of the main shielding cover, overall electric field strength decreases with decreasing angle of the main shield edge flap;72.5kV cup-shaped contact vacuum interrupter using finite element analysis method, change the length of the bellows shield cover for electric field strength simulation calculation. According to the simulation results, the electric field strength at the crest gradually decreases with increasing length of the bellows shield. It is concluded that the length of the main shielding cover of the vacuum interrupter, the angle of turning out of the edge of the main shielding cover, and the length of the bellows shield cover have an important influence on the insulation performance of the vacuum interrupter. © 2024 IEEE.

关键词： Bellows

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Kalman Filter Adaptive Speed Tracking control for High-speed Trains with Noise Interference 7

Kalman Filter Adaptive Speed Tracking Control for High-speed...

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7th International Conference on intelligent Robotics and control Engineering, IRCE 2024

作者： Zhang, Chunli Xie, Yuwei Yan, Lei Qian, Fucai Xi'an University of Technology Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing College of Automation and Information Engineering Xi'an China

ISBN: (纸本)9798350352399

In this paper, high-speed train is regarded as a single prime point, a new tracking control method combining adaptive control and Kalman filtering is proposed. This paper solves the noise interference problem in the tracking control process of high-speed train. The method first linearises the original system, then uses Kalman filtering to do model estimation, and the controller is designed for the predictive model through adaptive control. Finally, MATLAB is used to simulate and verify the effectiveness of this method. This proposed method successfully solves the problems of nonlinearity, noise interference and unknown parameters in system. The error caused by resistance in the high-speed train tracking control process can be dealt with effectively. © 2024 IEEE.

关键词： Kalman filters

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A Cycling Friendliness Measurement System for Dockless Bike-sharing Dynamic Scheme

Journal of Network Intelligence

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Journal of Network Intelligence 2023年第4期8卷 1557-1569页

作者： Li, Ben Huang, Dejuan Liao, Lyuchao Xiao, Hankun Ma, Huankun Fujian Provincial Universities Key Laboratory of Industrial Control Data Analysis Fujian Provincial Universities Engineering Research Center for Intelligent Driving Technology School of Transportation Fujian University of Technology Fuzhou350118 China

The rapid growth of Dockless Bike-sharing (DLBS) provides an excellent opportunity to meet the strong demand for convenient green travel services. However, with the increasing number of cyclists and DLBS, the issue of DLBS friendliness faces several challenges: (1) the hardness of renting in empty fences;(2) the difficulty of parking in overload fences;(3) different road conditions have different effects on cycling friendliness. To deal with these challenges, we design a DLBS friendliness (DLBSF) sys-tem, consisting of DLBS recommendation (DLBSR) system and DLBS scoring (DLBSS) system to comprehensively alleviate the problem of decreasing friendliness. The former optimizes cycling friendliness by first identifying the overload fences where the morning peak tide phenomenon is most prominent, and then provides guidance for cyclists to park the nearest idle fences. The latter gives the riding friendliness scheme by scoring and analyzing each road section to improve friendliness. Experiments on real-world DLBS datasets verify the accuracy, effectiveness, and feasibility of the proposed DLBSF system. © 2023, Taiwan Ubiquitous Information CO LTD. All rights reserved.

关键词： Fences

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