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Chinese Journal of electrical engineering 2024年第1期10卷 12-20页

作者： Hein Htet Aung Yuhuai Wang Jin Li ying zhang Tatsuo Takada School of electrical and Information engineering Tianjin UniversityTianjin 300072China Department of Power Generation and Transformation engineering Baoding Technical College of Electric PowerBaoding 071051China Measurement and electric Machine Control Laboratory Tokyo City UniversityTokyo 158-8557Japan

epoxy resin is widely used in the support,insulation,and packaging components of electrical equipment owing to their excellent insulation,thermal,and mechanical ***,epoxy-resin insulation often suffers from thermal and mechanical stresses under extreme environmental conditions and a compact design,which can induce electrical tree degradation and insulation failure in electrical *** this study,the photoelastic method is employed to investigate the thermal-mechanical coupling stress dependence of the electrical treeing behavior of epoxy *** electrical tree growth morphology and stress distribution were observed using the photoelastic *** correlation between the tree length and overall accumulated damage with an increase in mechanical stress is *** results show that compressive stress retards the growth of electrical trees along the electric field,while tensile stress has accelerating *** proves that the presence of thermal stress can induce more severe accumulated damage.

关键词： epoxy resin electrical tree degradation thermal stress mechanical stress photoelastic effects

Tropical Cyclone Monitoring and Analysis Techniques: A Review

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Journal of Meteorological Research 2024年第2期38卷 351-367页

作者： Chuanhai QIAN ying LI yinglong XU Xin WANG Zenghai zhang Gaozhen NIe Da LIU Shiwen zhang Institute for Development and Programme Design China Meteorological AdministrationBeijing 100081 Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081 National Meteorological Centre China Meteorological AdministrationBeijing 100081 National Satellite Meteorological Centre China Meteorological AdministrationBeijing 100081

Tropical cyclones(TCs),including tropical depressions and different categories of typhoons,hurricanes,and cyclonic storms,mostly originate over the oceans in the absence of direct ***,detailed monitoring and analysis of TCs has always been an unsolved *** the recent 20 years,great changes have taken place in domestic and foreign TC monitoring techniques,imposing a significant impact on TC operations and *** new technologies and products gradually emerge to support operations,with improved monitoring *** this paper,the progress on TC monitoring and analysis via meteorological satellites,radars,and airplanes in China and the world is reviewed,compared,and summarized,with special focuses on multisatellite fusion observations,in situ aircraft measurements,and some unconventional observation equipment such as rockets,saildrones,and underwater *** this basis,the paper points out future directions for improving TC monitoring and analysis in aid of better TC forecast and early warning.

关键词： tropical cyclone(TC) monitoring and analysis meteorological satellite aircraft reconnaissance

Low-viscosity oligoether esters(Oees)as high-efficiency lubricating oils:Insight on their structure‒lubricity relationship

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Friction 2024年第6期12卷 1133-1153页

作者： Hanwen WANG ying WANG Ping WeN Lin MA Mingjin FAN Rui DONG Chunhua zhang Shaanxi Key Laboratory of Phytochemistry College of Chemistry&Chemical EngineeringBaoji University of Arts and SciencesBaoji 721013China Key Laboratory of Shaanxi Province for Development and Application of New Transportation energy Chang’an UniversityXi’an 710064China

Development of energy-efficient lubricants is a way to reduce energy consumption for transportation,with the tendency to design molecules that are beneficial in reducing the viscosity of synthetic *** esters(Oees),as a low-viscosity ester base oil,have characteristics such as simple synthesis and excellent lubrication effect;however,the application of Oees in tribology field has rarely been *** objective of the present study is to investigate the effect of structure on the lubricating performance of Oees and to develop a predictive model for Oees based on quantitative structure‒property relationship(QSPR)through a combination of experiment and statistical *** showed that glycol chains contribute positively to lubrication with the ether functional groups increasing the sites of *** to branched-chain Oees,straight-chain Oees exhibited reduced wear,which was mainly due to the thicker adsorption film formed by the straight-chain ***,carbon films were detected on lightly worn surfaces,indicating that Oees underwent oxidation during the friction *** on the results of principal component analysis(PCA)and partial least squares(PLS),it could be found that the predictive models of viscosity‒temperature performance,thermal stability performance,coefficient of friction(COF),and wear volume(WV)performed well and *** them,COF and WV can be best predicted with an R^(2) of about 0.90.

关键词： oligoether esters(Oees) low-viscosity ester friction wear quantitative structure-property relationship(QSPR)

Dynamic access task scheduling of LeO constellation based on space-based distributed computing

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Journal of Systems engineering and electronics 2024年第4期35卷 842-854页

作者： LIU Wei JIN Yifeng zhang Lei GAO Zihe TAO ying Institute of Telecommunication and Navigation Satellites China Academy of Space TechnologyBeijing 100094China Innovation Center of Satellite Communication System China National Space AdministrationBeijing 100094China

A dynamic multi-beam resource allocation algorithm for large low earth orbit(LeO)constellation based on on-board distributed computing is proposed in this *** allocation is a combinatorial optimization process under a series of complex constraints,which is important for enhancing the matching between resources and requirements.A complex algorithm is not available because that the LeO on-board resources is *** proposed genetic algorithm(GA)based on two-dimen-sional individual model and uncorrelated single paternal inheri-tance method is designed to support distributed computation to enhance the feasibility of on-board application.A distributed system composed of eight embedded devices is built to verify the algorithm.A typical scenario is built in the system to evalu-ate the resource allocation process,algorithm mathematical model,trigger strategy,and distributed computation *** to the simulation and measurement results,the proposed algorithm can provide an allocation result for more than 1500 tasks in 14 s and the success rate is more than 91%in a typical *** response time is decreased by 40%com-pared with the conditional GA.

关键词： beam resource allocation distributed computing low earth obbit(LeO)constellation spacecraft access task scheduling

Medium-and long-term sustainable supply approaches and strategies for essential and typical strategic resources in China

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Frontiers of engineering Management 2024年第3期11卷 576-583页

作者： Ting YAO Zhen-ying LI Yue-Jun zhang School of economics and Trade Hunan University of Technology and BusinessChangsha 410205China Center for Resource and environmental Management Hunan UniversityChangsha 410082China Business School Hunan UniversityChangsha 410082China

This paper examines sustainable supply strategies for essential and strategic resources in China,addressing both domestic requirements and global supply *** the context of intense global competition for resources and substantial internal demand,China’s significant role as a major consumer and global supplier is pivotal in the dynamics of the global supply *** study highlights China’s dependence on imports for essential resources and the critical need for resilient supply chains to enhance national security and promote environmental *** referencing international experiences and accounting for China’s specific circumstances,this study proposes strategic initiatives,including updating the strategic resource catalog,imposing export controls on key minerals,promoting resource conservation,and enhancing global *** strategies aim to reduce external dependencies and support global resource *** proposed framework can help policymakers ensure long-term resource security and manage resources more effectively in complex global landscapes.

关键词： resources sustainable supply supply chain security stability

Analysis of China’s PM_(2.5)and ozone coordinated control strategy based on the observation data from 2015 to 2020

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Journal of environmental Sciences 2024年第4期138卷 385-394页

作者： Liuwei Kong Mengdi Song Xin Li ying Liu Sihua Lu Limin Zeng Yuanhang zhang State Key Joint Laboratory of environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China

The coordinated control of PM_(2.5)and ozone has become the strategic goal of national air pollution *** the gradual decline in PM_(2.5)concentration and the aggravation of ozone pollution,a better understanding of the coordinated control of PM_(2.5)and ozone is urgently ***,we collected and sorted air pollutant data for 337 cities from 2015 to 2020 to explore the characteristics of PM_(2.5)and ozone pollution based on China’s five major air pollution *** results show that it is necessary to continue to strengthen the emission reduction in PM_(2.5)and ozone precursors,and control NO_(x) and VOCs while promoting a dramatic emission reduction in PM_(2.5).The primary method of curbing ozone pollution is to strengthen the emission control of VOCs,with a long-term strategy of achieving substantial emission reductions in NO_(x),because VOCs and NO_(x) are also precursors to PM_(2.5);hence,their reductions also contribute to the reduction in PM_(2.5).Therefore,the implementation of a multipollutant emission reduction control strategy aimed at the prevention and control of PM_(2.5)and ozone pollution is the only means to realize the coordinated control of PM_(2.5)and ozone.

关键词： PM_(2.5) Ozone Coordinated control Multipollutant reduction

Development review and the prospect of oil shale in-situ catalysis conversion technology

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Petroleum Science 2024年第2期21卷 1385-1395页

作者： Li Wang Chen-Hao Gao Rui-ying Xiong Xiao-Jun zhang Ji-Xiang Guo The Unconventional Oil and Gas Institute China University of Petroleum-BeijingBeijing102200China

As an unconventional resource, oil shale possesses abundant reserves and significant potential for industrial applications. The rational and efficient development of oil shale resources holds immense importance in reducing national energy demand. In-situ catalytic technology, characterized by its high efficiency, low pollution, and minimal energy consumption, represents a key direction for future oil shale development. This paper provides a comprehensive review of research progress in in-situ oil shale mining technology, oil shale pyrolysis catalysts, the pyrolysis mechanism of kerogen, and the compatibility of different heating processes and catalysts. Furthermore, the paper proposes future research directions and prospects for oil shale in-situ catalytic technology, including reservoir modification, highefficiency catalyst synthesis, injection processes, and high-efficiency heating technology. These insights serve as valuable technical references for the advancement of oil shale in-situ catalytic technology.

关键词： Oil shale In-situ catalytic technology Pyrolysis catalyst Kerogen pyrolysis mechanism

Intramolecular carbon isotope of propane from coal-derived gas reservoirs of sedimentary basins:Implications for source,generation and post-generation of hydrocarbons

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Geoscience Frontiers 2024年第4期15卷 230-244页

作者： Xiaofeng Wang Peng Liu Wenhui Liu Changjie Liu ying Lin Dongdong zhang State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China College of Safety Science and engineering Xi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Shale Oil and Gas enrichment Mechanisms and effective Development Petroleum Exploration and Production Research InstituteSINOPECBeijing 100083China Northwest Institute of eco-environment and Resources Chinese Academy of SciencesLanzhou 730000China Department of earth and Planetary Sciences University of CaliforniaRiversideRiversideCA 92521USA

An intramolecular isotopic study was conducted on natural gases collected from coal-derived gas reser-voirs in sedimentary basins of China to determine their position-specific isotope *** propane from the Turpan-Hami Basin exhibited negativeΔc-T(δ13Ccentral-δ13Cterminal)values ranging from-3.9‰to-0.3‰,with an average of-2.1‰.Propane from the Ordos Basin,Sichuan Basin,and Tarim Basin showed positiveΔC-T values,with averages of 1.3‰,5.4‰and 7.6‰,*** carbon isotope compositions reveal the precursors and the propane generation pathways in the petroliferous *** formed from the thermal cracking of TypeⅢkerogen has largerδ13Ccentral andδ13Cterminal values than propane from TypeⅠ/Ⅱ*** precursor for natural gases collected in this study is identified to be TypeⅢ*** our data to calculated results for thermal cracking of TypeⅢkerogen,we found that propane from the low-maturity gas reservoir in the Turpan Basin was generated via the i-propyl radical pathway,whereas propane from the Sulige tight gas reservoir in the Ordos Basin was formed via the n-propyl radical pathway.δ13Cterminal values covered a narrow range across basins,in contrast toδ*** terminal carbon position in propane is less impacted by microbial oxidation and more relevant to maturity levels and ***,δ13Cterminal has a good potential to infer the origin and maturity level of natural *** examining post-generation processes,we proposed an improved identification strategy for microbial oxidation of natural gases,based on the position-specific carbon isotope distributions of *** from the Liaohe Depression of the Bohai Bay Basin and the Sichuan Basin were detected of post-generation microbial ***,position-specific carbon isotope composition of propane provides new insights into the generation mechanism and post-generation processes of natural gas in the geological period at the atomic level.

关键词： Intramolecular isotope Position-specific isotope Kinetic isotope effects Microbial anaerobic oxidation

Rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)} with fast-responsive photochromism and switchable luminescence properties

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Journal of Rare earths 2024年第2期42卷 286-292,I0003页

作者： Hong Cui Yanli Yang Xue Bai Xu Han Wensha zhang ying Lu Shuxia Liu Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of education College of ChemistryNortheast Normal UniversityChangchun 130024China

Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{Re(DMF)_(4)(H_(2)O)_4Re(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](Re = La(1),Pr(2),Sm(3),eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution *** analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by Re^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic ***,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(eu)display strong characteristic emissions of rare earth ions based on f-f ***,compound4(eu) has a longer fluorescence lifetime up to 566.74 μ***,co mpounds 3(Sm) and 4(eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.

关键词： Inorganic-organic hybrid Keggin-type polyoxometalates Rare earths Photochromism Photoluminescence

event-triggered H_(∞) consensus control for input-constrained multi-agent systems via reinforcement learning

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Control Theory and Technology 2024年第1期22卷 25-38页

作者： Jinxuan zhang Chang-e Ren College of Information engineering Capital Normal UniversityBeijing100089China

This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.

关键词： H_(∞)optimal control Input constrains Multi-agent systems(MASs) Reinforcement learning(RL)