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Holocene Dynamics of Vegetation Cover and Their Driving Mechanisms in Asian Drylands

Journal of Earth Science 2025年第2期36卷 839-842页

作者： Shengqian Chen Yuanhao Sun Guoqiang Ding Xianyong Cao Alpine Paleoecology and Human Adaptation Group State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and ResourcesInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China MOE Key Laboratory of West China's Environmental System College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China

0 *** Asian drylands,encompassing the northern East Asian monsoon region(NMA),the westerlies-dominated arid central Asia(ACA)and arid west Asia(AWA),are ecologically fragile areas and among the most sensitive regions to global *** regions are significant dust sources of the Northern Hemisphere(e.g.,Uno et al.,2009),playing a vital role in global climate change and marine biogeochemical cycles.

关键词： dynamics marine biogeochemical cycles global changethese asian drylandsencompassing east asian monsoon arid central asia aca driving mechanisms Holocene

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Hybrid Models for Forecasting Allocative Localization Error in Wireless Sensor Networks

International Journal of Cognitive Computing in Engineering

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International Journal of Cognitive Computing in Engineering 2025年 6卷 333-350页

作者： Li, Guo Sheng, Hongyu State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China College of Robotics Beijing Union University Beijing 100101 China

This study presents a machine learning-based approach to forecast Allocative Localization Error (ALE) in Wireless Sensor Networks (WSNs), addressing challenges such as dynamic network topologies and resource constraints. The approach utilizes Radial Basis Function (RBF) models enhanced with advanced optimization algorithms, including Coot Optimization Algorithm (COA), Smell Agent Optimization (SAO), and Northern Goshawk Optimization (NGO) to improve ALE prediction accuracy. Hybrid models (RBCO, RBSO, and RFNG) are developed by integrating these optimization techniques, which refine critical RBF parameters, such as spread and center selection, through iterative optimization. Furthermore, an ensemble framework (RSNC) combines all three optimizers with RBF to achieve superior performance. The proposed methods are validated using R2 and RMSE metrics, demonstrating their ability to minimize ALE, optimize resource allocation, and extend network lifespans. The study highlights the practical applicability of these models in real-world scenarios, such as environmental monitoring and industrial automation, offering enhanced efficiency and economic benefits. The RFNG model, in particular, achieved the lowest Mean Absolute Relative Error (MARE) of 0.049, demonstrating superior performance compared to other approaches in the test section. Moreover, RBNG obtained 0.069 and 0.978 values for the RMSE and R2, respectively, which were the most suitable values compared to other models, namely RBGO, RBSO, RSNC, and RBF. The results indicate that the proposed hybrid models significantly improve the prediction of ALE, leading to more efficient node deployment and better network management. This research provides valuable insights into leveraging machine learning for WSN optimization, benefiting researchers, network engineers, and industries relying on sensor networks for applications such as environmental monitoring, smart cities, and asset tracking. © 2025

关键词： Radial basis function networks

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Evetac Meets Sparse Probabilistic Spiking Neural Network: Enhancing Snap-Fit Recognition Efficiency and Performance

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IEEE robotics and Automation Letters 2025年第6期10卷 5353-5360页

作者： Fang, Senlin Ding, Haoran Liu, Yangjun Liu, Jiashu Zhang, Yupo Li, Yilin Kong, Hoiio Yi, Zhengkun Faculty of Data Science City University of Macau 999078 China Chinese Academy of Sciences Guangdong Provincial Key Laboratory of Robotics and Intelligent System Shenzhen Institutes of Advanced Technology Shenzhen518055 China City University of Hong Kong Hong Kong University of Macau 999078 China Shenzhen Institute of Advanced Technology Shenzhen518055 China City University of Macau 999078 China Guangdong Provincial Key Laboratory of Robotics and Intelligent System Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen518055 China City University of Macau Faculty of Data Science 999078 China Chinese Academy of Sciences Key Laboratory of Biomedical Imaging Science and System Shenzhen518055 China

Snap-fit peg-in-hole assembly is common in industrial robotics, particularly for 3 C electronics, where fast and accurate tactile recognition is crucial for protecting fragile components. Event-based optical sensors, such as Evetac, are well-suited for this task due to their high sparsity and sensitivity in detecting small, rapid force changes. However, existing research often converts event data into dense images and processing them with dense methods, leading to higher computational complexity. In this letter, we propose a Sparse Probabilistic Spiking Neural Network (SPSNN) that utilizes sparse convolutions to extract features from the event data, avoiding computations on non-zero cells. We introduce the Forward and Backward Propagation Through Probability (FBPTP) method, which enables simultaneous gradient computation across all time steps, eliminating the need for the step-by-step traversal required by traditional Forward and Backward Propagation Through Time (FBPTT). Additionally, the Temporal Weight Prediction (TWP) method dynamically allocates weights for different time outputs, enhancing recognition performance with minimal impact on model efficiency. We integrate the Evetac sensor compactly into our robotic system and collected two datasets, named Tactile Event Ethernet (TacEve-Eth) and Tactile Event Type-C (TacEve-TC), corresponding to cantilever and annular snap-fit structures. Experiments show that the SPSNN achieves the superior trade-off between recognition performance and efficiency compared to other widely used methods, achieving the highest average recognition performance while reducing inference time by over 90% compared to FBPTT-based dense SNN baselines. © 2016 IEEE.

关键词： Robotic assembly

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Direct Ink Writing Method of Fractal Wearable Flexible Sensor Based on Conductive Graphene/Polydimethylsiloxane Ink

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Journal of Shanghai Jiaotong university(Science) 2025年第1期30卷 18-26页

作者： CHEN Junling GAO Feiyang ZHANG Liming ZHENG Xiongfei State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang110016China School of Mechanical Engineering Shenyang Ligong UniversityShenyang110159China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of SciencesShenyang110169China

Flexible electronic technology has laid the foundation for complex human-computer interaction system,and has attracted great attention in the field of human motion detection and soft *** has received an extensive attention due to its excellent electrical conductivity;however,how to use it to fabricate wearable flexible sensors with complex structures remains *** this study,we studied the rheological behavior of graphene/polydimethylsiloxane ink and proposed an optimal graphene ratio,which makes the ink have an good printability and conductivity at the same ***,based on the theory of Peano fractal layout,we proposed a two-dimensional structure that can withstand multi-directional tension by replacing the traditional arris structure with the arc *** that,we manufactured circular arc fractal structure sensor by adjusting ink composition and printing structure through direct ink writing ***,we evaluated the detection performance and repeatability of the *** method provides a simple and effective solution for fabricating wearable flexible sensors and exhibits the potential to fabricate 3D complex flexible electronic devices.

关键词： direct ink writing conductive graphene ink wearable flexible sensor strain sensing fractal structure

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A novel rotor dynamic balancing method based on blade tip clearance measurement without the once per revolution sensor

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Chinese Journal of Aeronautics 2025年第2期38卷 445-458页

作者： Weibo LI Weimin WANG Shuai ZHANG Jiale WANG Yulong LIN Tianqing LI Key Lab of Engine Health Monitoring-Control and Networking of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of High-end Compressor and System Technology Beijing University of Chemical TechnologyBeijing 100029China

The existence of the aeroengine casing,limited monitoring points,and multi-fault characteristics make obtaining the rotor’s vibration transmission characteristics challenging,resulting in difficulties accurately identifying the rotor *** paper utilizes a high-frequency composite sensor to monitor the engine’s blade tip clearance(BTC)and extracts unbalanced information from BTC signals for rotor dynamic balancing,while avoiding the need for the once per revolution(OPR)***,the vibration characteristics of the rotor-blade system under multi-fault conditions are ***,based on BTC measurement,a none OPR method and an unbalance identification method are proposed,in which the radial vibration of the blade tip in the BTC signals at different speeds is extracted and operated in the time domain to obtain the rotor unbalanced vibration,the signal is reconstructed,and cross-correlation analysis is used to accurately identify the magnitude and phase of the unbalanced ***,a rotor test bench is utilized for experimental *** results reveal that the dynamic balancing method based on the BTC signal can more precisely identify the rotor unbalance than the traditional rotor dynamic balancing *** application of this technique will effectively improve engine health management and fault prediction.

关键词： Aeroengine Rotor unbalance Composite sensor None once per revolution Blade tip clearance Dynamic balancing

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Dynamic responses of a piezoelectric semiconductor sandwich cylindrical shell covered with FGPS layers

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International Journal of Mechanics and Materials in Design 2025年 1-21页

作者： Zhu, Changsong Xu, Ziqi Liu, Jinxi State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

This paper focuses on the linear dynamic responses of a piezoelectric semiconductor (PS) sandwich cylindrical shell covered with functionally graded piezoelectric semiconductor (FGPS) layers. The PS sandwich cylindrical shell is composed of a PS core layer and two FGPS surface layers. The FGPS surface layer consists of the metal material (i.e., aluminum) and piezoelectric semiconductor material (i.e., zinc oxide). According to the virtual work, strain energy as well as kinetic energy of the FGPS sandwich cylindrical shell, the vibration governing differential equations are achieved on the basis of Hamilton’s principle. Then the theoretical solutions of the vibration responses are obtained by solving the governing equations with Navier method. Through numerical examples, the effect of the functionally graded index, thickness ratio, initial electron concentration and excitation frequency on the dynamic responses of the FGPS sandwich cylindrical shell is analyzed. The main novelty of the manuscript is that the induced electric potential, perturbation of electron concentration and radial displacement of the FGPS sandwich cylindrical shell may be regulated effectively by designing a proper initial electron concentration and applying an appropriate excitation frequency. The multi-field coupling mechanism among carrier, polarization as well as deformation is demonstrated. The current outcomes also show that the geometric parameter, circumference wave number and functionally graded index have a significant effect on the vibration frequency and damping characteristic of the FGPS sandwich cylindrical shell. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.

关键词： Piezoelectric materials

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Surge Characteristics of Planar-Gate Silicon Carbide MOSFET in the Third Quadrant

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IEEE Transactions on Power Electronics 2025年第8期40卷 10635-10648页

作者： Liang, Binqi Cui, Xiang Zheng, Feilin Li, Xuebao Li, Hongji Chen, Zhongyuan Jin, Rui Tang, Xinling State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Beijing Institute of Smart Energy Huairou Laboratory Beijing China Beijing Huairou Laboratory Beijing China

The planar-gate SiC MOSFET exhibits multiple conduction modes when operating in the third quadrant. As the current injection level increases, such as during surge events or other extreme conditions, the conduction characteristics are influenced by both the gate voltage and temperature. To gain a comprehensive understanding of the surge behavior of SiC planar MOSFET in the third quadrant, it is necessary to incorporate temperature calculations to deeply analyze the conduction mechanisms under varying operating conditions and high currents. In this article, experimental methods are used to investigate the surge conduction characteristics of SiC planar MOSFET in the third quadrant, and the surge capability of the device at different gate voltages is evaluated. Furthermore, scanning electron microscopy (SEM) is employed to analyze chip failures, and the mechanisms of surge-induced failure at various gate voltages are summarized. Finally, an electro-thermal coupling model for surge conditions in SiC planar MOSFET in the third quadrant is established. By integrating temperature calculations, the conduction modes under surge conditions are quantitatively analyzed, the results of modeling calculations showing good agreement with experimental data. The findings of this article provide valuable insights into the conduction characteristics and reliability assessment of SiC planar MOSFET in the third quadrant. © 1986-2012 IEEE.

关键词： MOSFET devices

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Physics-Based Predictions of the Month-by-Month Summer Western North Pacific Anomalous Anticyclone

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Journal of Climate 2025年第10期38卷 2187-2203页

作者： Zhu, Zhiwei Yang, Ying Liu, Boqi 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 State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing China

This study identified the distinct predictors of the western North Pacific anomalous anticyclone (WNPAC) in June, July, and August and revealed their independent influencing mechanisms on the formation of the summer WNPAC in each corresponding month. For the June WNPAC (AC_Jun), the North Atlantic warming (NAW) in April–May induces subsequently enhanced convection over the Indian Ocean and suppressed the convection over the tropical central Pacific, leading to AC_Jun via the Gill-type response. Meanwhile, the warming tendency over the western North Pacific from February to April, which reflects the slow decay of El Niño, results in AC_Jun through Indian Ocean warming. For the July WNPAC (AC_Jul), the cooling tendency from April to June over the central and eastern tropical Pacific is the sole predictor, which results in AC_Jul through the wind–evaporation–SST feedback. For the August WNPAC (AC_Aug), the tropical Atlantic warming (TAW) in June and July and the Bering Strait sea ice slow melting (BSSM) from April to May are the two predictors. While TAW has a similar influence on AC_Aug to that of NAW on AC_Jun, BSSM makes for AC_Aug by strengthening the westerly jet and subsequently atmosphere–ocean coupling over the North Pacific. Using these predictors, three physics-based empirical models (PEMs) for the seasonal predictions of AC_Jun, AC_Jul, and AC_Aug are conducted, which all outperform the National Centers for Environmental Prediction Climate Forecast system (CFS), shedding light on improving the seasonal prediction of the East Asian summer climate. © 2025 American Meteorological Society.

关键词： Heat flux

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Experimental Study on Geometry Characteristics of Turbulent Premixed Flames for Natural Gas/Air Mixtures

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Journal of Thermal Science 2025年第1期34卷 268-282页

作者： ZHENG Weilin WANG Qijiao XIAO Huahua CHEN Xiaoxiao XIE Fan ZENG Wen Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace UniversityShenyang 110136China State Key Laboratory of Fire Science University of science and Technology of ChinaHefei 230027China AVIC Shenyang Aircraft Design and Research Institute Shenyang 110035China

In this study,focusing on the geometry characteristics of spherical expanding flame,the turbulent premixed flames of natural gas/air mixtures were investigated in a fan-stirred turbulent *** effects of initial temperature(T=300-400 K),initial pressure(P=0.1-0.3 MPa),turbulence intensity(u'=1.0-2.7 m/s),oxygen volumetric percentage(φ(O_(2))=15%-21%)and carbon dioxide volumetric percentage(φ(CO_(2))=0-20%)were delved *** flame profile under the Cartesian coordinate system was derived from the schlieren images taken by the high-speed ***,from both macroscopic and microscopic perspectives,the influence of experimental conditions on the flame geometry characteristics was explored through flame front extraction,wavelet decomposition and network *** results demonstrate that for significant flame wrinkling,changes in species concentrations and turbulence intensity have more pronounced effects on the flame wrinkling *** wrinkling of the flame front maintains a certain degree of similarity,as evidenced by the locally concentrated distribution of the angles of the maximum fluctuation *** disturbance energy under large-scale(D6-D8)disturbances exhibits relatively high values with a similar trend,exerting a significant impact on the geometry characteristics of the flame *** peaks of correlation degree are scattered either with the decomposition scale or the development of flame radius,indicating no linear correlation between different detail ***,the probability distribution of node degrees in key wrinkled regions exhibits different trends with that of large-scale wrinkling and disturbance energy,especially with changes in initial *** occurs because the number of key wrinkles varies based on the perturbation's strength or the region's ***,an increase in the fluctuation frequency of the flame's local radius may not necessarily lead to an increase in the number of key folded regions.

关键词： geometry characteristics large-scale wrinkling wavelet decomposition network topology fan-stirred turbulent combustor

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Revealing the Impact of Ferromagnetic Elements on Fe-Based Amorphous Alloy Properties via ab initio Molecular Dynamics Simulations and Experiments

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Chinese Physics Letters 2025年第1期42卷 102-113页

作者： Jin-Hua Xiao Da-Wei Ding Lin Li Yi-Tao Sun Mao-Zhi Li Wei-Hua Wang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Institute of Physics Chinese Academy of SciencesBeijing 100190China Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices Renmin University of ChinaBeijing 100872China

A high saturation magnetic flux density(Bs)is essential for the development of Fe-based amorphous alloys for electromagnetic devices and ***,achieving a high Bs often compromises the glass-forming ability(GFA)of Fe-based amorphous *** study investigates the effects of ferromagnetic elements(Fe,Co,and Ni)on the microstructure and magnetic properties of Fe86B7C7 amorphous alloys through experiments and ab initio molecular dynamics *** analyzing both the experimental and simulation results,the relationship between the atomic structures,GFA,and magnetic properties of these amorphous alloys was *** results indicate that the GFA of the alloys is correlated with the proportion of icosahedral and body-centered cubic *** addition of Co and Ni not only improved the GFA of the alloys but also effectively increased the overall magnetic moment with an appropriate amount of Co and a small amount of *** increase in the magnetic moment primarily arises from the enhancement of the magnetic moment of Fe atoms,resulting from the redistribution between the spin-up and spin-down electrons of Fe-3d orbits,as well as the strong exchange interactions between Fe and Co and Fe–Ni *** results obtained offer valuable insights into the correlation between the atomic structure and magnetic properties of these amorphous alloys and suggest potential directions for the optimization of Fe-based amorphous alloys.

关键词： alloys microstructure magnetic

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