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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

Utilizing a metal-forging inspired chain combing strategy to enhance properties and expand applications of Nylon 66 plastic via heat inducing

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Nano Research 2024年第3期17卷 2164-2171页

作者： junyu Yang Jiangwei Zhang Nan Wang Guangyuan Zhou Division of Energy Materials Daglian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Innovation Center of Energy Material and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot 010021China

The mechanical properties of engineering plastics can be enhanced through effective surface mechanical treatment(SMT),which can be applied to various types of engineering plastics,eliminating the limitations of conventional polymer processing and could potentially extend their applications and improve their performance and reliability as structural-functional *** by metal forging,this work proposes a simple and effective SMT strategy to enhance the mechanical properties of polyamide 66(PA66).Tensile tests have shown that SMTed PA66 samples exhibit significant improvements in both Young’s modulus and ultimate tensile strength(UTS),with a 2104 MPa Young’s modulus,almost double that of the pristine samples,and a 35.56%increase in UTS,reaching 183 ***,the modulus within the localized SMTed surface layer could reach up to 14 GPa,which is approximately 14 times higher than that of the pristine *** Vickers hardness within the localized SMTed surface layer can be doubled,reaching 10.72 Hv,and the crystallinity can increase by approximately 20%compared to the untreated ***,force field molecular dynamics(FFMD)simulations were conducted to investigate the ternary relationship between the SMT method,PA66’s molecular structure,and its *** combination of MD simulations and versatile structural characterizations provides evidence that the SMT method’s mechanism,under heat induction,results in a chain-combing procedure that changes the polymer’s molecular morphology microscopically and enhances its mechanical properties macroscopically.

关键词： Nylon 66 mechanical properties hardness crystallinity structural characterizations molecular dynamics simulation

A dual-mode optical thermometer based on dual-excitation Bi^(3+),Sm^(3+)co-doped Y_(4)GeO_(8) phosphors

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Journal of Rare Earths 2024年第8期42卷 1437-1446,I0002页

作者： Danyu Zhang Yuxuan Luo junyu Chen Lianjie Li Hai Guo Department of Physics Zhejiang Normal UniversityJinhua321004China

Dual-excitation and dual-emission Y_(4)GeO_(8):Bi^(3+),Sm^(3+)phosphors were manufactured by traditional solidphase sintering *** X-ray diffraction,morphology,photoluminescence,energy transfer process and temperature sensing properties of Y_(4)GeO_(8):Bi^(3+),Sm^(3+)samples were comprehensively *** Y4GeO_(8):Bi^(3+),Sm^(3+)phosphors exhibit characteristic emissions of Bi^(3+)(^(3)P_(1)→^(1)S_(0)) and Sm^(3+)(^(4)G_(5/2)→^(6)H)under both 290 and 347 nm *** fluorescence intensity ratio and Commission International de L'Eclairage coordinates modes,Y_(4)GeO_(8):Bi^(3+),Sm^(3+)samples present excellent temperature measurement *** maximum relative sensitivity(S_(r-max)) values of the former are 1.55%/K(460 K,290 nm excitation) and 0.82%/K(506 K,347 nm excitation).The S_(r-max)(x) values of the latter are 0.21 %/K(437 K,290 nm excitation) and 0.15%/K(513 K,347 nm excitation).These results illustrate that Y_(4)GeO_(8):Bi^(3+),Sm^(3+)phospho rs can be used as a candidate material for a dual-mode optical thermometer under dual-excitation.

关键词： Dual-mode optical thermometer Luminescent properties Y_(4)GeO_(8):Bi^(3+) Sm^(3+)phosphors Rare earths

Domain Engineering the Flexoelectric Response of BaTiO_(3)–SrTiO_(3) Binary Films:A Phase Field Study

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Acta Mechanica Solida Sinica 2024年第4期37卷 590-597页

作者： junyu Tao Fan Zhang Jianyuan Zhang Weijin Chen Yue Zheng School of Materials Shenzhen Campus of Sun Yat-sen UniversityShenzhen518107China Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-sen UniversityGuangzhou510275China State Key Laboratory of Optoelectronic Materials and Technologies School of PhysicsSun Yat-sen UniversityGuangzhou510275China Centre for Physical Mechanics and Biophysics School of PhysicsSun Yat-sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China

The flexoelectric effect describes the interplay between material polarization and strain *** much research has focused on control strategies for flexoelectricity,the impact of ferroelectric domain structure on the flexoelectric effect remains *** phase field simulations,we conduct a comparative study on the flexoelectric response of two types of BaTiO_(3)–SrTiO_(3) binary films:BaTiO_(3)–SrTiO_(3) multilayers and(Ba,Sr)TiO_(3) solid *** findings reveal that the flexoelectric response of these two systems,at the same Ba/Sr ratio,differs not only in magnitude but also in other aspects like temperature dependence,linearity,and hysteresis,due to their different ferroelectric domain structures and evolution *** study deepens our current understanding of flexoelectricity in ferroelectrics and suggests“domain engineering”as a potential way to tailor this effect.

关键词： Ferroelectric Flexoelectricity Multilayers Solid solution Phase field

Weakly-supervised instance co-segmentation via tensor-based salient co-peak search

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Frontiers of Computer Science 2024年第2期18卷 83-92页

作者： Wuxiu QUAN Yu HU Tingting DAN junyu LI Yue ZHANG Hongmin CAI School of Computer Science Guangdong Polytechnic Normal UniversityGuangzhou 510665China School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006China

Instance co-segmentation aims to segment the co-occurrent instances among two *** task heavily relies on instance-related cues provided by co-peaks,which are generally estimated by exhaustively exploiting all paired candidates in point-to-point ***,such patterns could yield a high number of false-positive co-peaks,resulting in over-segmentation whenever there are mutual *** tackle with this issue,this paper proposes an instance co-segmentation method via tensor-based salient co-peak search(TSCPS-ICS).The proposed method explores high-order correlations via triple-to-triple matching among feature maps to find reliable co-peaks with the help of co-saliency *** proposed method is shown to capture more accurate intra-peaks and inter-peaks among feature maps,reducing the false-positive rate of co-peak *** having accurate co-peaks,one can efficiently infer responses of the targeted *** on four benchmark datasets validate the superior performance of the proposed method.

关键词： weakly-supervised co-segmentation co-peak tensormatching deep network instance segmentation

Reheat effect on the improvement in efficiency of the turbine driven by pulse detonation

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Defence Technology（防务技术） 2024年第1期31卷 200-210页

作者： junyu Liu Zhiwu Wang Zixu Zhang Junlin Li Weifeng Qin Jingjing Huang School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Mechanical Engineering College Xi’an Shiyou UniversityXi’an 710065China

Due to the strong unsteadiness of pulse detonation,large flow losses are generated when the detonation wave interacts with the turbine blades,resulting in low turbine *** that the flow losses are dissipated into the gas as heat energy,some of them can be recycled during the expansion process in subsequent stages by the reheat effect,which should be helpful to improve the detonationdriven turbine *** this into account,this paper developed a numerical model of the detonation chamber coupled with a two-stage axial turbine,and a stoichiometric hydrogen-air mixture was *** improvement in turbine efficiency attributable to the reheat effect was calculated by comparing the average efficiency of the stages with the efficiency of the two-stage *** research indicated that the first stage was critical in suppressing the flow unsteadiness caused by pulse detonation,which stabilized the intake condition of the second stage and consequently allowed much of the flow losses from the first stage to be recycled,so that the efficiency of the two-stage turbine was *** a 95%confidence level,the efficiency improvement was stable at 4.5%—5.3%,demonstrating that the reheat effect is significant in improving the efficiency of the detonation-driven turbine.

关键词： Pulse detonation turbine engine Hydrogen detonation Turbine efficiency Reheat effect Multi-cycle detonation

Effect of End Shape on Flow and Heat Transfer Characteristics of Two Parallel Plates

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Journal of Thermal Science 2024年第3期33卷 815-832页

作者： ZHANG Guang HONG Tianxiao WANG Dongrui XIN Jialin TAO junyu LIN Zhe Key Laboratory of Fluid Transmission Technology of Zhejiang Province Zhejiang Sci-Tech UniversityHangzhou310018China

Flow around a pair of flat plates is a basic hydrodynamics *** this paper,the flow and heat transfer characteristics of two parallel plates with different edge shapes are numerically *** different inclined angles,the influence of chamfered and rounded structures with different sizes at the end-edge on unsteady flow and heat transfer characteristics of two parallel plates are *** is found that the instability and unsteadiness of flow decrease with the increase of end-edge size,and the non-uniformity of wake velocity of both rounded and chamfered plates decreases *** non-uniformity of wake temperature increases firstly and then decreases at a small inclined angle,and the amplitude becomes the largest when S_(rou)(S_(cha))=3,while it basically keeps monotonically increasing at a large inclined ***,the global heat transfer performance of the flat plate is obviously affected by the end-edge modification,especially the chamfered *** the increase of chamfered size,the global Nusselt number basically shows the decreasing *** study provides a theoretical basis for the application of plate-shape structure in engineering fields.

关键词： two parallel plates end shape flow characteristic heat transfer numerical simulation

From the perspective of experimental practice: High-throughput computational screening in photocatalysis

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Green Energy & Environment 2024年第1期9卷 1-6页

作者： Yunxuan Zhao junyu Gao Xuanang Bian Han Tang Tierui Zhang Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China Institute for AI Industry Research(AIR) Tsinghua UniversityBeijing100084China

Photocatalysis,a critical strategy for harvesting sunlight to address energy demand and environmental concerns,is underpinned by the discovery of high-performance photocatalysts,thereby how to design photocatalysts is now generating widespread interest in boosting the conversion efﬁ-ciency of solar *** the past decade,computational technologies and theoretical simulations have led to a major leap in the development of high-throughput computational screening strategies for novel high-efﬁciency *** this viewpoint,we started with introducing the challenges of photocatalysis from the view of experimental practice,especially the inefﬁciency of the traditional“trial and error”***-sequently,a cross-sectional comparison between experimental and high-throughput computational screening for photocatalysis is presented and discussed in *** the basis of the current experimental progress in photocatalysis,we also exempliﬁed the various challenges associated with high-throughput computational screening ***,we offered a preferred high-throughput computational screening procedure for pho-tocatalysts from an experimental practice perspective(model construction and screening,standardized experiments,assessment and revision),with the aim of a better correlation of high-throughput simulations and experimental practices,motivating to search for better descriptors.

关键词： Photocatalysis High-throughput computational screening Photocatalyst Theoretical simulations Experiments

A Survey on Model Predictive Control of DFIGs in Wind Energy Conversion Systems

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1085-1104页

作者： Shuo Yan junyu Chen Minghao Wang Yongheng Yang Jose M.Rodriguez STEM College RMIT UniversityMelbourneAustralia Hong Kong Polytechnic University Hong KongChina State Key Laboratory of Internet of Things for Smart City(UM) Department of Electrical and Computer EngineeringUniversity of MacaoMacaoChina College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Universidad San Sebastin Campus BellavistaSantiago de ChileCLSantiago de Chile 000000Chile IEEE

This paper presents a comprehensive study on the model predictive control(MPC)of doubly fed induction generators(DFIG)in wind energy conversion systems(WECS);in particular the MPC of the rotor side *** general principle of prevalent MPC strategies is discussed to introduce the theoretical framework in the first ***,mainstream and high-performance MPC methods of DFIGs have been identified as model predictive current control(MPCC),model predictive torque control(MPTC),and model predictive power control(MPPC).Starting from analyzing dynamic models,these MPC strategies are investigated in terms of operating principles and technical *** paper further investigates implementation of MPC strategies in unbalanced *** on the quantitative and qualitative analysis of several case studies,performance of various MPC schemes is compared and their special features are *** for designing MPC strategies of DFIGs in WECS are provided.

关键词： Doubly fed induction generator(DFIG) model predictive control(MPC) wind energy