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Aggregation Modeling of system Frequency Response Under Inertia Control of Grid-following Direct-drive Wind Turbine

Dianli Xitong Zidonghua/Automation of Electric Power systems 2025年第10期49卷 39-48页

作者： Jiang, Chao Yang, Dongfeng Guo, Shujia Liu, Xiaojun Zhou, Shuyu Cao, Zhichong Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education Northeast Electric Power University Jilin132012 China School of Automation and Electrical Engineering Zhejiang University of Science and Technology Hangzhou310023 China State Grid Jilin Electric Power Research Institute Changchun130000 China

The inertia control of grid-following direct-drive wind turbines significantly influences the system frequency response pattern afrer disturbances. However, current research has not clearly identified the dominant response link of direct-drive wind turbines in frequency regulation, while the modeling is too complicated to be suitable for frequency characteristic analysis. Therefore, the linearized models under inertia control are derived for two typical types of direct-drive wind turbines according to the aerodynamic equations, generator models, power control link, and control circuit structure. The fast physical process of current control-boost circuit/stator voltage dynamic loop is clearly understood and reasonably ignored. It is revealed that the two types of direct-drive wind turbines have a common frequency response mechanism which can be described as the cascade effect of the speed regulator-wind rotor motion equation. Furthermore, combined with the frequency response model of synchronous unit, the aggregation model of system frequency response under the inertia control of grid-following direct-drive wind turbines is constructed, and the aggregation model is reduced to a second-order model by the balance truncation method for analytical calculation of frequency extremes. The accuracy and applicability of the aggregation model and its reduced-order model are verified by MATLAB/Simulink simulation, and the influence of control parameters and system states on frequency dynamic characteristics and stability margin is analyzed. © 2025 Automation of Electric Power systems Press. All rights reserved.

关键词： Electric power system control

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Comprehensive understanding of microplastics in compost: Ecological risks and degradation mechanisms

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science of the Total Environment 2025年 958卷 178104页

作者： Dong, Dazhuang Gao, Wenjing Li, Lele Liu, Yuxin Dai, Yaodan State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing100875 China Department of Earth and Space Science University of Science and Technology of China Anhui Hefei230026 China School of Resources and Environmental Engineering Hefei University of Technology Hefei230009 China

The introduction of microplastics (MPs) into soil ecosystems via compost application has emerged as a critical environmental concern. However, the ecological risks and degradation behavior of MPs in compost remain insufficiently understood. This review addresses these gaps by synthesizing recent findings on MPs in composting systems, focusing on their sources, impacts on compost quality, ecological risks, and degradation mechanisms. MP sources vary significantly across compost matrices-domestic waste, sludge, and agricultural waste‑leading to differences in their types and quantities. MPs adversely impact compost quality by disrupting its physical structure and impairing fertility, aeration, and water retention. Furthermore, their persistence after compost application can result in long-term environmental accumulation, posing risks to soil ecosystems and biological health. This review also explores the aging and degradation of MPs during composting, a complex process influenced by physical, chemical, and biological mechanisms. Finally, we propose future research directions, emphasizing the development of standardized methodologies to assess MP behavior in compost and strategies to mitigate associated risks. These insights contribute to advancing sustainable waste management and environmental protection practices. © 2024 Elsevier B.V.

关键词： Compost Degradation mechanisms Ecological risks Influencing factors Microplastics

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Immobilizing PdCd dual-atom sites on rhombic dodecahedral nitrogen-doped carbon matrix for enhancing electrocatalytic CO2 reduction reaction

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Chemical Engineering Journal 2025年 513卷

作者： Gong, Yanlong Ran, Xiaoli Yang, Xiaohong Xiong, Shixian Gu, Feng Wang, Shufen Li, Jiangcheng Fu, Haitao An, Xizhong Key Laboratory for Ecological Metallurgy of Multimetallic Mineral Ministry of Education Northeastern University Shenyang110819 China Shenyang110819 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate System Jiangxi University of Science and Technology Nanchang330013 China Alber Particle Science and Technology Research Institute Jiangxi Nanchang330000 China Qingdao266101 China

Developing novel and efficient catalysts is the key for enhancing the electrochemical reduction performance of carbon dioxide (CO2RR) that is considered as a promising strategy for achieving carbon neutrality. In this work, we, for the first time, report a Pd–Cd dual-atom catalyst embedded in a rhombic dodecahedral nitrogen-doped carbon matrix (PdCd DACs–NCrd) that is designed for breaking the limitation of linear scaling relationships and overcoming the defects of current single atomic catalysts (SACs) of CO2RR. The as-prepared PdCd DACs–NCrd exhibits exceptional selectivity for converting CO, achieving a Faradaic efficiency (FEco) of 98.99 % at −0.62 V (vs. RHE) and over 95 % of its initial CO selectivity after 60 h of electrolysis. Density functional theory (DFT) calculation reveals that introducing Cd single atom adjacent to Pd single atom results in a weak d–d orbital coupling, boosting the bridging adsorption of *COOH intermediates and the desorption of CO product, and suppressing the H2 evolution competitive reaction. These unique electrochemical properties in turn improve the selectivity, activity, and stability of the PdCd DACs–NCrd towards CO2–CO conversion. © 2025

关键词： Reaction intermediates

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Big-data-driven vessel destination prediction for smart port management

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Engineering Applications of Artificial Intelligence 2025年 154卷

作者： Chen, Jin Zhang, Qiang Liang, Maohan Peng, Chang Chen, Chen Sanya Institute Hunan University of Science and Technology China National Key Laboratory of Space Integrated Information System China Hubei Key Laboratory of Inland Shipping Technology School of Navigation Wuhan University of Technology China Department of Civil and Environmental Engineering National University of Singapore Singapore College of Computer Science and Electronic Engineering Hunan University China

The accurate prediction of vessel destinations is crucial for enhancing maritime traffic efficiency, optimizing port management, and improving regional economic analysis. However, destination information in Automatic Identification system (AIS) data is often missing or inaccurate, which undermines the reliability of maritime analytic. Traditional vessel destination prediction methods primarily focus on measuring trajectory similarities, which results in high computational complexity. This study develops a deep learning approach to vessel destination prediction by transforming the problem into an image classification task. Rasterized images of historical destination ports and vessel trajectories are generated, incorporating AIS data within a fixed spatial context. A multi-scale residual convolutional network is constructed to extract relevant trajectory and port distribution features. To enhance the representation of trajectory endpoints, which are critical for predicting the destination port, a multi-attention mechanism is introduced. This mechanism increases the learning weight assigned to endpoint features, improving prediction accuracy. Finally, a classification network predicts the destination port based on the extracted features. The performance of the proposed method is evaluated using AIS data from the Denmark Strait. Experimental results demonstrate that the model outperforms existing methods, highlighting its potential for applications in smart port management and maritime traffic optimization. © 2025 Elsevier Ltd

关键词： Waterway transportation

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A Game-Theoretic Approach for Satellites Beam Scheduling and Power Control in a Mega Hybrid Constellation Spectrum Sharing Scenario

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IEEE Internet of Things Journal 2025年

作者： Li, Wei Jia, Luliang Chen, Yingwu Chen, Quan Yan, Jungang Qi, Nan National University of Defense Technology College of Systems Engineering Changsha China Space Engineering University College of Space Information Beijing China National University of Defense Technology College of Aerospace Science and Engineering Changsha China Nanjing University of Aeronautics and Astronautics Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology Nanjing210016 China

A mega hybrid constellation of Low Earth Orbit (LEO) and Geosynchronous Orbit (GEO) satellites represents a typical architecture for future space networks. However, the emergence of such large constellations exacerbates the shortage of spectrum resources. To address this issue, this paper investigates a hierarchical optimization method for beam scheduling and power control of LEO satellites, aiming to extend the available spectrum by sharing the downlink spectrum of GEO satellites. In the upper-layer optimization, a many-to-one matching game model is constructed to achieve optimal matching of LEO satellite beams and LEO Users (LU). A distributed beam matching learning algorithm (DBMLA) is designed to find a stable matching solution for the model, with the convergence of the algorithm theoretically proven. In the lower-layer optimization, an LEO beam power level optimization game model is developed for discrete LEO beam power levels. This model is demonstrated to be an exact potential game with at least one Nash Equilibrium (NE). To solve this NE, a dynamic power allocation logarithmic learning algorithm (DPALLA) is proposed. simulation results verify that the proposed DBMLA-DPALLA hierarchical optimization scheme effectively balances convergence time and accuracy compared to traditional independent optimization strategies. By leveraging the combined effects of the two optimization strategies, it better mitigates the co-channel interference experienced by GEO satellites and improves the average network satisfaction of the LUs. © 2025 IEEE.

关键词： Cochannel interference

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Generative AI-Enhanced Cooperative MEC of UAVs and Ground Stations for Unmanned Surface Vehicles 59

Generative AI-Enhanced Cooperative MEC of UAVs and Ground St...

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59th Annual Conference on Information sciences and systems, CISS 2025

作者： You, Jiahao Jia, Ziye Dong, Chao Wu, Qihui Han, Zhu Nanjing University of Aeronautics and Astronautics The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology Nanjing211106 China Southeast University National Mobile Communications Research Laboratory Nanjing211111 China University of Houston Department of Electrical and Computer Engineering HoustonTX77004 United States Kyung Hee University Department of Computer Science and Engineering Seoul446-701 Korea Republic of

ISBN: (纸本)9798331513269

The increasing deployment of unmanned surface vehicles (USVs) require computational support and coverage in applications such as maritime search and rescue. Unmanned aerial vehicles (UAVs) can offer low-cost, flexible aerial services, and ground stations (GSs) can provide powerful supports, which can cooperate to help the USVs in complex scenarios. However, the collaboration between UAVs and GSs for USVs faces challenges of task uncertainties, USVs trajectory uncertainties, heterogeneities, and limited computational resources. To address these issues, we propose a cooperative UAV and GS based robust multi-access edge computing framework to assist USVs in completing computational tasks. Specifically, we formulate the optimization problem of joint task offloading and UAV trajectory to minimize the total execution time, which is in the form of mixed integer nonlinear programming and NP-hard to tackle. Therefore, we propose the algorithm of generative artificial intelligence-enhanced heterogeneous agent proximal policy optimization (GAI-HAPPO). The proposed algorithm integrates GAI models to enhance the actor network ability to model complex environments and extract high-level features, thereby allowing the algorithm to predict uncertainties and adapt to dynamic conditions. Additionally, GAI stabilizes the critic network, addressing the instability of multi-agent reinforcement learning approaches. Finally, extensive simulations demonstrate that the proposed algorithm outperforms the existing benchmark methods, thus highlighting the potentials in tackling intricate, cross-domain issues in the considered scenarios. © 2025 IEEE.

关键词： Unmanned surface vehicles

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Effect of 20 MeV proton irradiation on the electrical properties of β-Ga2O3 Schottky barrier diodes with field plate

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Applied Physics Letters 2025年第16期126卷

作者： Feng, Yahui Guo, Hongxia Zhang, Jinxin Ouyang, Xiaoping Bai, Ruxue Zheng, Xuefeng Ma, Xiaohua Hao, Yue State Key Laboratory of Wide-Bandgap Semiconductor Devices and Integrated Technology Faculty of Integrated Circuit Xidian University Xi'an710071 China The School of Materials Science and Engineering Xiangtan University Xiangtan411105 China National Key Laboratory of Strong Pulse Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China The School of Space Science and Technology Xidian University Xi'an710071 China

In this Letter, the impact of 20 MeV proton irradiation on β-Ga2O3 Schottky barrier diodes (SBDs) with field plates has been investigated. After proton irradiation with fluences of 2 × 1012 and 5 × 1012 p/cm2, the forward current density (JF) decreased from 294.0 to 250.5 and 192.0 A/cm2, respectively. The turn-on voltage (Von) increased from 0.78 to 0.82 and 0.84 V, as measured by current-voltage (I-V) testing. Capacitance-voltage (C-V) measurements showed that the net carrier concentration in the lightly doped drift region of β-Ga2O3 decreased from 1.95 × 1016 to 1.83 × 1016 and 1.38 × 1016 cm−3 after proton irradiation. Additionally, C-V measurements at different frequencies reveal that capacitance gradually decreases as proton fluence increases, though the frequency has little effect on capacitance. The effect of proton irradiation on β-Ga2O3 SBDs was also characterized using low-frequency noise and x-ray photoelectron spectroscopy. The results indicated that the voltage noise spectral density (Sv) gradually increases with proton fluence and bias voltage before and after irradiation due to the introduction of defects. This study provides an important reference for the reliability assessment of β-Ga2O3 SBDs. © 2025 Author(s).

关键词： Schottky barrier diodes

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Co-Existing Fast and Slow Afterslip Processes Following the 2015 Gorkha (Mw 7.8) Earthquake Resolved by Full Time-Series Inversion

SSRN

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SSRN 2025年

作者： Zhao, Zeyan Yue, Han Zhang, Jian Hu, Yan Zhou, Yijian Liu-Zeng, Jing Wang, Kang School of Earth and Space Sciences Peking University Beijing China Institute of Deep Space Sciences Deep Space Exploration Laboratory Hefei China School of Earth and Space Sciences University of Science and Technology of China Hefei China Department of Earth and Planetary Sciences University of California RiversideCA United States School of Earth System Science Institute of Surface‐Earth System Science Tianjin University Tianjin China EarthScope Consortium Inc

The 2015 Gorkha (Mw=7.8) earthquake ruptured the downdip portion of the Main Himalayan Thrust. Afterslip following this event provides valuable insights into the frictional properties on the thrust interface, yet its amplitude and distribution remain controversial. In this study, we incorporate long-term GNSS and InSAR data and correct for the viscoelastic relaxation simulated using a regional 3-D viscoelastic model. We adopt the corrected data in a novel inversion algorithm and resolve two spatially separated afterslip processes with different decay times: fast afterslip near the bottom of the coseismic rupture, possibly stopped the mainshock and triggered the Mw 7.3 aftershock 17 days later, and slow afterslip extending further downdip. By comparing the afterslip and aftershock patterns, we identify distinct partitioning of seismic and aseismic slip behaviors at the bottom of the seismogenic zone, which reflects local heterogeneities in frictional properties at the transition depths. © 2025, The Authors. All rights reserved.

关键词： Miocene

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Low shrinkage Cf/SiC composites by vat photopolymerization of polycarbosilane containing precursor slurry and PIP process

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Ceramics International 2025年

作者： Jin, Baojie Li, Shan Zheng, Xinqi Hu, Chuanqi Wang, Xuye Chen, Zihuan Duan, Wenyan Liu, Bingshan Cui, Congcong Li, Wei Zhang, Ge Wang, Gong Technology and Engineering Centre of Space Utilization Chinese Academy of Sciences Beijing100094 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China Key Laboratory of Optical System Advanced Manufacturing Technology Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun130033 China

Carbon fiber reinforced silicon carbide (Cf/SiC) composites were fabricated using vat photopolymerization (VPP) technology and precursor infiltration and pyrolysis (PIP) process. The photosensitive slurry was firstly prepared by blending SiC powder, mixed photosensitive resin and chopped carbon fiber. By introducing ceramic precursor vinyl hydropolycarbosilane (VHPCS) into the photosensitive slurry, the flexural strength of the green bodies was enhanced and the linear shrinkage of the debinding bodies was decreased. When the addition of VHPCS was 20 wt%, the flexural strength of the green bodies reached 37.37 MPa, and the linear shrinkage after debinding was 3.82%. Then the influence of different chopped carbon fiber content on various properties of Cf/SiC composites was investigated. When the carbon fiber content was 15 vol%, the flexural strength and bulk density, and porosity of the Cf/SiC composites measuring 190.20 ± 18.57 MPa, 2.40 ± 0.01 g/cm3, and 1.21 ± 0.08%, respectively. TEM and XRD confirmed the existence of C, 6H-SiC, and 3C-SiC in the matrix, where 6H-SiC exhibited crystalline characteristics and 3C-SiC exhibited amorphous characteristics. This work provides a new strategy for VPP additive manufactured Cf/SiC complex structure. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Bending strength

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Low-Earth Orbital Lifetime Prediction Based on Parameter Sensitivity Analysis and Deep Learning

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IEEE Transactions on Aerospace and Electronic systems 2025年

作者： Chen, Shun-Yi Yang, Zhen Wang, Hua Lu, Lin State Key Laboratory of Space System Operation and Control Changsha410073 China National University of Defense Technology College of Aerospace Science and Engineering Changsha410073 China China Astronaut Research and Training Center Beijing100094 China

This article proposes an intelligent prediction method for the orbital lifetime of resident space objects (RSOs) in low Earth orbit. This method is intended to satisfy the computational efficiency and accuracy requirements when predicting the large-scale RSOs. It helps to analyze the distribution and uncertainty of RSOs' lifetime. First, based on the semi-analytical orbit prediction model, a parameter sensitivity analysis method for the orbital lifetime is proposed, and the parameters that affect the orbital lifetime are investigated. Second, using a fully connected neural network, an orbital lifetime prediction model is established based on deep learning. The hyperparameters of the deep learning model are optimized using the black-winged kite algorithm. Finally, by combining the sensitivity analysis with the deep learning model, an intelligent prediction method is proposed for the rapid prediction of orbital lifetime. simulation results show that the proposed intelligent prediction method accurately determines the orbital lifetime of RSOs and has higher prediction efficiency than the traditional prediction method. The research results provide an effective calculation and analysis tool for predicting the orbital lifetime of large-scale RSOs in the future. © 2025 IEEE.

关键词： Prediction models

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