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2024 3rd International Conference on Acoustics, Fluid Mechanics and Engineering, AFME 2024

作者： Gao, Zhe Wei, Ming Li, Wensen Chen, Cunzhuang Li, Changle Zhao, Jie State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150000 China Hubei Institute of Aerospace Chemical Technology Xiangyang441003 China

Solid propellant is one of the main components of rocket engines, and the casting of low-viscosity propellant slurry usually uses a vacuum casting process. During the vacuum casting process, the rheological properties of solid propellant slurry are complex, and the theoretical analytical method cannot intuitively and accurately analyze its flow characteristics. Therefore, this paper numerically simulates the casting process through simulation software, uses the Herschel-Bulkley model to characterize the changes in the flow characteristics of solid propellant slurry during the vacuum casting process, and studies the effects of different hopper angles and anti-break vacuum plug shapes on the slurry's rheological properties. By analyzing parameters such as slurry mass flow rate, velocity, residual amount in the hopper, and surface pressure of the plug, the appropriate hopper angle and the bottom edge angle of the anti-break vacuum plug are selected. Finally, the slurry leveling characteristics under suitable hopper and plug conditions are analyzed. The results indicate that a hopper angle of 140° and an anti-break vacuum plug bottom angle of 120° are optimal. The entire vacuum casting process takes approximately 42 seconds, and the overall slurry leveling is good. As the casting progresses, the slurry gradually compacts and levels out, and the bubbles at the bottom of both sides of the combustion chamber gradually disappear. © Published under licence by IOP Publishing Ltd.

关键词： Hoppers

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Development of a Four-Dimensional Diagnostic Analysis Model for Assessing Ensemble Forecast Uncertainty

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Journal of Meteorological Research 2025年第2期39卷 288-302页

作者： Fei PENG Yuejian ZHU Jing CHEN Xiaoli LI Jian TANG CMA Earth System Modeling and Prediction Centre China Meteorological Administration （CMA） State Key Laboratory of Severe Weather Science and Technology China Meteorological Administration Key Laboratory of Earth System Modeling and Prediction China Meteorological Administration National Meteorological Centre China Meteorological Administration

Evaluating whether an ensemble prediction system(EPS) can accurately represent forecast uncertainty is a key aspect of model development and ensemble forecast applications. In this study, a four-dimensional diagnostic analysis model for assessing ensemble forecast uncertainty is proposed, by analyzing the relationship between the ensemble spread and root-mean-square error(RMSE) of the ensemble mean in terms of their temporal evolution(one-dimensional) and spatial distribution(three-dimensional), together with use of the linear variance calibration(LVC) *** on this model and the daily operational forecast data of the China Meteorological Administration(CMA) global EPS(CMA-GEPS) in December 2022–November 2023, characteristics of the CMA-GEPS forecast uncertainty are diagnosed and analyzed, and compared against the state-of-the-art operational global EPS of ECMWF. Generally,there is a deficiency in CMA-GEPS, which underestimates the forecast uncertainty, especially in the tropics. However, at certain initialization times in some seasons and over some locations, the spread appears greater than the RMSE, indicating an overestimation of forecast uncertainty. Moreover, CMA-GEPS performs better in capturing the forecast uncertainty of lower-level variables than upper-level variables; and in comparison with the mass and thermal fields, the forecast uncertainty of the dynamic field is better represented. Diagnostic analysis using the LVC method reveals that the relevance between the ensemble variance and the ensemble mean error variance of CMA-GEPS increases with forecast lead time, and the problem of underestimated forecast uncertainty is continuously alleviated. In addition, ECMWF EPS behaves distinctly better than CMA-GEPS in representing the forecast uncertainty and its growth process, the reasons for which are discussed and elucidated from the perspective of shortcomings in the methods to generate the initial and model perturbations, the ensemble size, and the f

关键词： diagnostic analysis ensemble forecast ensemble variance-error variance relationship forecast uncertainty spread-error relationship

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Complete Gait Phase Recognition Based on Muscle Synergy Using PSO-CNN-LSTM Algorithm

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IEEE Sensors Journal 2025年第10期25卷 16775-16786页

作者： Zhang, Kewen Li, Xiaoling Chen, Xin Yu, Longjie Jin, Yinan Fan, Bingfei Du, Mingyu Bao, Guanjun Wu, Xinyu Cai, Shibo Zhejiang University of Technology College of Mechanical Engineering Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang Province Hangzhou310023 China Zhejiang University of Technology College of Mechanical Engineering Hangzhou310023 China ZJUT Yinhu Research Institute of Innovation and Entrepreneurship Zhejiang University of Technology Fuyang Hangzhou310023 China Shenzhen Institutes of Advanced Technology Guangdong Provincial Key Laboratory of Robotics and Intelligent System Chinese Academy of Sciences Key Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institutes of Advanced Technology Shenzhen518055 China

Accurately recognizing gait phases, by applying proper instrumentation and measurement, is significant in walking rehabilitation training for patients with impaired mobility. In this study, seven phases of complete stand-walk–stand cycle as well as continuous daily walking were recognized based on muscle synergy and particle swarm optimization (PSO)-convolutional neural network (CNN)-long short-term memory (LSTM) model. First, the complete stand-walk–stand walking cycle was divided into starting phase, terminal swing phase, loading response phase, mid-stance phase, terminal stance phase, initial swing phase, and stopping phase, based on the features of surface electromyography (sEMG) collected by portable sEMG acquisition system and measured motion data of lower limb. Second, a muscle weight matrix and an activation sequence matrix were calculated by using nonnegative matrix factorization (NMF). Finally, a PSO-CNN-LSTM network was designed to recognize the complete stand-walk–stand cycle by applying the abovementioned matrices as input. Fourteen subjects volunteered to perform linear walking experiments under procedure to verify the feasibility of the proposed approach by comparing results with other classifiers and features. Experimental results show that the proposed approach was capable of achieving an average recognition accuracy of up to 85.384%. This work will offer a promising gait recognition method for rehabilitation robots to achieve natural and flexible human-robot interaction. © 2001-2012 IEEE.

关键词： Non-negative matrix factorization

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Multi-view fully connected graph to fuse multi-sensor signals for mechanical equipment remaining useful life prediction

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Journal of Manufacturing systems 2025年 80卷 1029-1052页

作者： Wu, Jinxin He, Deqiang Jin, Zhenzhen Zhao, Ming Li, Xianwang Chen, Yanjun Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology School of Mechanical Engineering Guangxi University Nanning530004 China State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive Zhuzhou412001 China Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic Technology 541004 China Guangxi Liugong Machinery Co. Ltd Liuzhou545007 China

Accurate remaining useful life prediction is essential for enhancing equipment reliability and optimizing maintenance strategies. However, existing methods struggle to effectively integrate multi-sensor data while quantifying uncertainty. To address these challenges, a multi-view fully connected graph neural network is proposed for multi-sensor mechanical equipment remaining useful life prediction. Firstly, local fully connected graphs and global graphs are constructed to comprehensively characterize the multi-view spatial correlations from global and local views. Meanwhile, the graph convolution operations are performed on local and global graphs to extract the intricate spatial dependencies within multi-sensor signals. Then, the learned multi-view spatial representations are fed into the temporal convolutional network to capture the temporal dependencies across sensor timestamps. Finally, a joint optimization network is developed to simultaneously predict the remaining useful life and its associated prediction interval, enabling uncertainty quantification. Extensive experiments on two multi-sensor monitoring degradation datasets demonstrate the superior performance of the proposed model, offering valuable technical support for predictive maintenance. © 2025 The Society of Manufacturing Engineers

关键词： Predictive maintenance

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Development of a high-resolution near-surface meteorological forcing dataset for the Third Pole region

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Science China Earth Sciences 2025年第4期68卷 1274-1290页

作者： Yaozhi JIANG Wenjun TANG Kun YANG Jie HE Changkun SHAO Xu ZHOU Hui LU Yingying CHEN Xin LI Jiancheng SHI School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu611731China Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing100084China National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and ResourcesInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Tsinghua University(Department of Earth System Science)-Xi’an Institute of Surveying and Mapping Joint Research Center for Next-Generation Smart Mapping Beijing100084China National Space Science Center Chinese Academy of SciencesBeijing100190China

Recently,the Third Pole(TP)region has experienced rapid environmental *** data are essential for hydrometeorological and ecological applications but still have large uncertainties on the TP owing to the heterogeneous land surface,complex terrain,and sparse weather *** this study,a long-term(1979–2020)high-resolution(1/30°)meteorological forcing dataset for the TP(TPMFD)was developed,as a sister to the widely used China Meteorological Forcing Dataset(CMFD).The TPMFD comprises seven components necessary for driving land surface *** have previously contributed precipitation and downward shortwave radiation data for the TPMFD,and this study presents the development of five other components and focuses on validations for all ***,2-meter air temperature,2-meter specific humidity,10-meter wind speed,and surface air pressure were generated by combining the fifth-generation atmospheric reanalysis for European Center for Medium-Range Weather Forecasts(ERA5),a short-term high-resolution atmospheric simulation,and in situ observations,and the downward longwave radiation was calculated using semi-physical *** cross-validation and independent-validation demonstrated that most variables in the developed dataset outperformed those in widely used reanalysis datasets,including ERA5,ERA5-Land,and the Global Land Data Assimilation system(GLDAS).This dataset is expected to be beneficial for climate analyses and modeling applications of land-surface processes on the TP.

关键词： Meteorological data Third Pole High-resolution Data downscaling and merging

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SGT-LLC: LiDAR Loop Closing Based on Semantic Graph with Triangular Spatial Topology

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IEEE robotics and Automation Letters 2025年第4期10卷 3326-3333页

作者： Wang, Shaocong Cao, Fengkui Wang, Ting Chen, Xieyuanli Shao, Shiliang Shenyang Institute of Automation Chinese Academy of Sciences State Key Laboratory of Robotics Shenyang110016 China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang110016 China University of Chinese Academy of Sciences Beijing110003 China National University of Defense Technology College of Intelligence Science and Technology Changsha410003 China

Inspired by how humans perceive, remember, and understand the world, semantic graphs have become an efficient solution for place representation and location. However, many current graph-based LiDAR loop closing methods focus on extracting adjacency matrices or semantic histograms to describe the scene, which ignore a lot of multifaceted topology information for efficiency. In this letter, we propose a LiDAR loop closing method based on semantic graph with triangular spatial topology (SGT-LLC), which fully considers both semantic and spatial topological information. To ensure that descriptors contain robust spatial information while maintaining good rotation invariance, a local descriptor based on semantic topological encoding and triangular spatial topology is proposed, which can effectively correlate scenes and estimate 6-DoF poses. In addition, we aggregate local descriptors from various nodes in the graph using fuzzy classification to create lightweight database and efficient global search. Extensive experiments on KITTI, KITTI360, Apollo, MulRAN and MCD datasets prove the superiority of our approach, compared with state-of-art methods. © 2025 IEEE.

关键词： Graph theory

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Interdecadal Change of Relationship between North Atlantic Oscillation and Tropical Cyclone Genesis Frequency over the Western North Pacific

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Journal of Climate 2025年第8期38卷 1855-1870页

作者： Wang, Zhen Zhou, Botao Zhao, Jiuwei State Key Laboratory of Climate System Prediction and Risk Management Key Laboratory of Meteorological Disaster Ministry of Education Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Nanjing China School of Atmospheric Sciences Nanjing University of Information Science and Technology Nanjing China

This article investigates the relationship between spring (March–May) North Atlantic Oscillation (NAO) and the tropical cyclone genesis frequency (TCGF) over the western North Pacific (WNP) from June to November. It is found that their relationship appears insignificant from 1950 to 1971, intensifies significantly from 1972 to 2010, and then weakens again since 2011. The interdecadal change of this relationship is strongly influenced by the meridional displacement of the North Atlantic jet stream (NAJS). During 1972–2010, the NAJS is located southward, facilitating the spread of Rossby wave energy to the equatorial region and enhancing the NAO impact on sea surface temperatures (SSTs) over the tropical North Atlantic (TNA). Generally, positive (negative) phases of the NAO relate to negative (positive) TNA SST anomalies in spring, subsequently triggering positive (negative) SST anomalies in the central Pacific through the wind–evaporation–SST feedback. The central Pacific SST anomalies, intensifying from summer to autumn, lead to a basin-uniform circulation anomaly over the WNP and ultimately control the WNP TCGF. Conversely, in the other two periods, owing to the northward shift of the NAJS, the influence of the NAO is constrained to the extratropics, thereby disrupting the linkage between the NAO and TNA SST anomalies. As a result, the interannual relationship of spring NAO with the WNP TCGF weakens. The decadal meridional shift of the NAJS is supposed to be associated with the phase transition of the Pacific decadal oscillation. © 2025 American Meteorological Society.

关键词： Tropical cyclone

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Edge-Cloud Cooperation-Driven Intelligent Sustainability Evaluation Strategy Based on IoT and CPS for Energy-Intensive Manufacturing Industries

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IEEE Internet of Things Journal 2025年第9期12卷 12287-12297页

作者： Ma, Shuaiyin Huang, Yuming Chen, Yanping Xiao, Qinge Xu, Jun Leng, Jiewu Xi’an University of Posts and Telecommunications Shaanxi Key Laboratory of Network Data Analysis and Intelligent Processing Xi’an Key Laboratory of Big Data and Intelligent Computing School of Computer Science and Technology Xi’an710121 China Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China Xidian University Advanced Manufacturing Technology Innovation Center Guangzhou Institute of Technology Guangzhou510555 China Guangdong University of Technology Guangdong Provincial Key Laboratory of Computer Integrated Manufacturing System State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment Guangzhou510006 China

The advancement of the Industry 5.0 in information technology has led to increased interest in integrating edge-cloud cooperation with Internet of Things (IoT) and cyber-physical system (CPS) designs. This integration effectively reduces service delays and provides real-time analysis feedback to physical spaces, attracting attention from both academia and industry. These advanced technologies enhance production system intelligence, their alignment with circular economy principles for promoting sustainability has been overlooked. To address this gap, this article proposes an intelligent sustainability evaluation strategy driven by edge-cloud cooperation, IoT, and CPS. The proposed approach aims to enhance production sustainability and intelligence through circular economy perspectives. It introduces improved gray relation analysis and deep clustering network techniques to extract meaningful insights from diverse indicators within the evaluation system. By analyzing relationships between different equipment and workshops, it provides an analytical method that enhances production efficiency while reducing energy consumption and resource waste. To further validate the proposed method, an illustrative example using a partner company’s production data demonstrates its accuracy. © 2014 IEEE.

关键词： Circular economy

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Influence of different anodised nanoporous structures on the anti-icing and electrical properties of transmission Al lines

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High Voltage 2025年第1期10卷 167-177页

作者： Xu Dai Yuan Yuan Jie Xiao Chenghao Jiang Xujiang Hua Huiying Xiang Tao Zhu Guoyong Liu Jiang Zhou Ruijin Liao State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina College of Materials Science and Engineering Chongqing UniversityChongqingChina Dongfang Electric Machinery Co. LtdDeyangChina

Ice accumulation of overhead transmission lines can lead to serious damage to power *** nanostructured Al conductors are proposed to replace the de-icing or ice-melting equipment for economic advantages,good anti-icing properties and robust electrical *** under different direct current densities is adopted to fabricate two nanostructures on Al conductors,including the reticular and honeycomb-like nanoporous *** to pure Al conductors,the anodised surface of honeycomb-like nanoporous structures exhibits lower ice adhesion(3.82 kPa)and ice *** conductor steel reinforced treated in the proposed method has also been validated to exhibit a significant anti-glaze icing ***-tionally,corona performance and line loss are experimentally measured and calculated to prove good electrical *** 0.27 A Al strand shows the highest corona inception voltage(27.86 kV)and the lowest AC resistance(4.65Ω/km),which is attributed to the good dielectric property and heat ***,the proposed anti-icing transmission conductors show profound application potential for power systems.

关键词： electrical structures properties

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Causes of Winter Persistent Extreme Cold Events in Northeastern China

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Advances in Atmospheric Sciences 2025年第4期42卷 780-793页

作者： Ming YANG Qingjiu GAO Tim LI State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China Department of Atmospheric Sciences University of Hawaii at ManoaHonoluluHI 96822USA

Persistent(5-day or longer)extreme cold events(ECEs)over northeastern China during the boreal winter of 1979–2020 are investigated using daily minimum temperature(Tmin)from the China Meteorological Data *** extreme cooling area and intensity indices associated with the ECEs exhibit a dominant 10–40-day periodicity,indicating a close link with atmospheric intraseasonal oscillations(ISOs).The ECEs are categorized into W-and *** the former,the low-frequency cooling associated with the ISO first penetrates into the western boundary of the northeastern China domain and later occupies the entire domain at its peak *** upper-tropospheric circulation associated with this type is characterized by a northwest–southeast-oriented Rossby wave train,expanding from the Ural Mountains to the western Pacific *** the latter,the cooling invades the northern boundary first and then penetrates into the entire *** upper tropospheric precursory signal associated with this type is a zonally oriented negative geopotential height anomaly,which slowly moves southward.A downward-propagating signal is observed in the stratospheric potential vorticity field prior to the peak cooling,implying a possible stratospheric *** addition to the W-and N-types,ECEs can also occur in a localized region near either at the northern or southern boundary of the domain.

关键词： extreme cold events low-frequency ISO mode Rossby wave train composite analysis downward propagation potential vorticity

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