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Stationary Almost Markov ε-Equilibria for discounted Stochastic Games with Borel Spaces and Unbounded Payoffs

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Journal of Systems Science & Complexity 2024年第4期37卷 1672-1684页

作者： WU Yiting ZHANG Junyu HUANG song School of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China School of Software and Microelectronics Peking UniversityBeijing 100871China

This paper is concerned with nonzero-sum discrete-time stochastic games in Borel state and action spaces under the expected discounted payoff *** payoff function can be *** transition probability is a convex combination of finite probability measures that are dominated by a probability measure on the state space and depend on the state *** suitable conditions,the authors establish the existence of stationary almost Markov ε-equilibria and give an approximation method via some stochastic games with bounded ***,a production game is introduced to illustrate the applications of the main result,which generalizes the bounded payoff case.

关键词： Almost Markovε-equilibrium Borel state space expected discounted payoff criterion nonzero-sum stochastic games unbounded payoffs

design,fabrication,and characterization of hierarchical mechanical metamaterials

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Frontiers of Mechanical Engineering 2024年第1期19卷 73-83页

作者： Jian song Junfei YAN Bengang YI Automotive Engineering Research Institute BYD Auto Industry Co.Ltd.Shenzhen 518000China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China

Natural mechanical materials,such as bamboo and bone,often exhibit superior specific mechanical properties due to their hierarchical porous *** the principle of hierarchy as inspiration can facilitate the development of hierarchical mechanical metamaterials(HMMs)across multiple length scales via 3d *** this work,we propose self-similar HMMs that combine octet-truss(OCT)architecture as the first and second orders,with cubic architecture as the third or more *** HMMs were fabricated using stereolithography 3d printing,with the length sizes ranging from approximately 200µm to the centimeter *** compressive stress–strain behaviors of HMMs exhibit a zigzag characteristic,and the toughness and energy absorption can be significantly enhanced by the hierarchical *** compressive moduli are comparable to that of natural materials,and the strengths are superior to that of most polymer/metal foams,alumina hollow/carbon lattices,and other natural ***,the flexural stress–strain curves exhibit a nonlinear behavior,which can be attributed to the hierarchical architecture and local damage *** relatively high mechanical properties can be attributed to the synergistic effect of the stretch-dominated OCT architecture and the bending-dominated cube ***,an ultralight HMM-integrated unmanned aerial vehicle(HMM-UAV)was successfully designed and *** HMM-UAV is~85%lighter than its bulk counterpart,remarkably extending the flight duration time(~53%).This work not only provides an effective design strategy for HMMs but also further expands the application benchmark of HMMs.

关键词： 3d printing mechanical metamaterials hierarchical architecture mechanical behavior unmanned aerial vehicle(UAV)

Assessments of data-driven deep Learning Models on One-Month Predictions of Pan-Arctic Sea Ice Thickness

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Advances in Atmospheric Sciences 2024年第7期41卷 1379-1390页

作者： Chentao song Jiang ZHU Xichen LI Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis ***,deep learning predictions of sea ice thickness(SIT)have yet to receive ample *** this study,two data-driven deep learning(dL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/*** models enable monthly predictions of Arctic SIT without considering the complex physical processes *** comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both dL models can effectively predict the spatiotemporal features of SIT *** the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most *** models also demonstrate robust performances in predicting SIT and SIE during extreme *** effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications.

关键词： Arctic sea ice thickness deep learning spatiotemporal sequence prediction transfer learning

Noninvasive beam diagnosis based on the TM_(010)mode

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Nuclear Science and Techniques 2024年第7期35卷 115-125页

作者： Chuang-Ye song Wen-Hui Huang department of Engineering Physics Tsinghua University BeijingBeijing100084China of Education Beijing100084China

A resonant cavity based on the TM_(010)mode is an effective tool for noninvasive beam characterization. This technique has the advantages of a high signal-to-noise ratio, compact structure, and is related to multiple parameters compared with other beam monitors. In this study, high-precision measurements of the bunch charge, arrival time, bunch length, and energy parameters based on the TM_(010)mode are discussed. A cavity beam arrival time monitor(BAM) utilizing a phase cavity has been widely used in many facilities. Regarding bunch-length measurements, the influence of the beam energy, beam offset,and longitudinal spectrum on the TM_(010)mode are carefully considered to reduce errors, and the theoretical resolution of two cavities with different frequencies is analyzed. Owing to the dependence of the beam velocity of the beam loss factor, this method can also be used for the detection low beam energy using two cavities with the same frequency but different cavity lengths. A set of three cavities with different lengths and frequencies of 1.902 and 11.424 GHz is presented for measuring the four aforementioned parameters.

关键词： TM_(010)mode Noninvasive diagnosis Beam length Low energy

The Extended Hybrid Carrier-Based Multiple Access Technology for High Mobility Scenarios

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China Communications 2024年第1期21卷 53-68页

作者： Ge song Xiaojie Fang Xuejun Sha School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering *** this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless *** employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution *** implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is *** addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access *** proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility *** results have verified the feasibility and advantages of the proposed *** with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications.

关键词： extended hybrid carrier system high mo-Received:Jun.09,2023 Revised:Nov.20,2023 Editor:Yuanwei Liu bility communications multiple access

Functionalization of cellulose carbon dots with different elements(N,B and S)for mercury ion detection and anti-counterfeit applications

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Chinese Chemical Letters 2024年第7期35卷 355-359页

作者： Xiaoning Li Quanyu Shi Meng Li Ningxin song Yumeng Xiao Huining Xiao Tony d.James Lei Feng Second Affiliated Hospital of dalian Medical University Dalian 116023China Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control Department of Environmental Science and EngineeringNorth China Electric Power UniversityBaoding 071003China department of Chemical Engineering and Limerick Pulp&Paper Centre University of New Brunswick15 Dineen DriveFredericton NB E3B 5A3Canada department of Chemistry University of BathBath BA27AYUnited Kingdom School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Mercury ion(Hg^(2+)),as one of the most toxic heavy metal ions,accumulates easily in the environment,which can generate potential hazards to the ecosystem and human *** effectively detect and remove Hg^(2+),we fabricated four types of carbon dots(Cds)using carboxymethyl nanocellulose as a carbon source doped with different elements using a hydrothermal *** the Cds exhibited a strong fluorescence emission,excitation-dependent emission and possessed good water ***,the four fluorescent Cds were used for Hg^(2+)recognition in aqueous solution,where the Cds-N exhibited better sensitivity and selectivity for Hg^(2+)detection,with a low limit of detection of 8.29×10^(-6)mol/*** was determined that the fluorescence quenching could be ascribed to a photoinduced charge-transfer processes between Hg^(2+)and the *** addition,the Cds-N were used as a smart invisible ink for anticounterfeiting,information encryption and ***,the Cds-N were immersed into a cellulose(CMC)-based hydrogel network to prepare fluorescent hydrogels capable of simultaneously detecting and adsorbing Hg^(2+).We anticipate that this research will open possibilities for a green method to synthesize fluorescent Cds for metal ion detection and fluorescent ink production.

关键词： Carbon dots Functional groups Hg^(2+)detection Mechanism Anti-counterfeiting

Mechanism and experimental study on the fruit detachment of Chinese wolfberry through reciprocating vibration

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 47-58页

作者： song Mei Jinpeng Wang Zhiyu song dunbing Tang Cheng Shen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Nanjing Research Institute for Agricultural Mechanization Ministry of Agriculture and Rural AffairsNanjing 210014China Nanjing Forestry University Nanjing 210037China

In order to realize the efficient and high-quality mechanical picking for Chinese wolfberry,firstly,the forced reciprocating vibration picking principle of the Chinese wolfberry branch was studied,and the mechanical model of vibration picking was established based on the simplified cantilever model,and the response analysis and solution of all positions for the branch were carried *** the same time,the critical mechanical model of fruit detachment under the condition of fruit hanging on branches was established,and the theoretical values of inertia force for each component of the branch were ***,through actual measurement and finite element modeling,the natural frequency and forced vibration response simulation for each component of the branch of Chinese wolfberry terminal branch model were both studied,and the relationship between single-point periodic excitation force and high-quality fruit shedding parameters was ***,according to the conclusion of the picking model,a test bench with many groups of adjustable parameters was ***,the last branch of fruit-hanging Chinese wolf berry for Ningqi No.1 was taken as the experimental object,a four-level orthogonal experiment was designed with three factors:frequency,amplitude and entrance ***,the net picking rate,damage rate and false picking rate were taken as the evaluating indicators,referring to the comprehensive scores of the three *** was concluded that the primary and secondary relations of factors affecting the picking effect are frequency,amplitude and entrance angle,and the best operation parameters are frequency of 20 Hz,amplitude of 15 mm,and entrance angle of 45°,then,a hand-held vibration picker with setting parameters was trial-produced,and the optimal parameter combination was verified in the Chinese wolfberry planting base of the National Chinese wolfberry Engineering and Technology Research *** results showed that the net picking rate of rip

关键词： Chinese wolfberry branches reciprocating vibration inertial force orthogonal experiment

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai song Hui KANG Min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back Scatter diffraction(EBSd),Scanning Electron Microscopy(SEM),X-Ray diffraction(XRd),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORdS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

dynamic Constraint-driven Event-Triggered Control of Strict-Feedback Systems Without Max/Min Values on Irregular Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 569-580页

作者： Zhuwu Shao Yujuan Wang Zeqiang Li Yongduan song the State Key Laboratory of Power Transmission Equipment&System Security and New Technology and the School of AutomationChongqing UniversityChongqing 400044China IEEE

This work proposes an event-triggered adaptive control approach for a class of uncertain nonlinear systems under irregular *** the constraints considered in most existing papers,here the external irregular constraints are considered and a constraints switching mechanism(CSM)is introduced to circumvent the difficulties arising from irregular output *** on the CSM,a new class of generalized barrier functions are constructed,which allows the control results to be independent of the maximum and minimum values(MMVs)of constraints and thus extends the existing ***,we proposed a novel dynamic constraint-driven event-triggered strategy(dCdETS),under which the stress on signal transmission is reduced greatly and no constraints are violated by making a dynamic trade-off among system state,external constraints,and inter-execution *** is proved that the system output is driven to close to the reference trajectory and the semi-global stability is guaranteed under the proposed control scheme,regardless of the external irregular output *** also verifies the effectiveness and benefits of the proposed method.

关键词： Adaptive control dynamic constraint-driven event-triggered control irregular output constraints nonlinear strict-feed-back systems