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An Online Q-Learning Method for Linear-Quadratic Nonzero-Sum Stochastic Differential Games with Completely Unknown Dynamics

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Journal of Systems Science & Complexity 2024年第5期37卷 1907-1922页

作者： zhang bao-Qiang WANG Bing-Chang CAO Ying School of Control Science and Engineering Shandong UniversityJinan 250000China

In this paper,the authors design a reinforcement learning algorithm to solve the adaptive linear-quadratic stochastic n-players non-zero sum differential game with completely unknown *** each player,a critic network is used to estimate the Q-function,and an actor network is used to estimate the control input.A model-free online Q-learning algorithm is obtained for solving this kind of *** is proved that under some mild conditions the system state and weight estimation errors can be uniformly ultimately bounded.A simulation with five players is given to verify the effectiveness of the algorithm.

关键词： Actor-critic algorithm model-free adaptive control nonzero-sum stochastic game reinforcement learning

Thermodynamic and thermoelectric properties of titanium oxycarbide with metal vacancy

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 787-795页

作者： bao zhang Jiusan Xiao Shuqiang Jiao Hongmin Zhu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Innovation Group of Marine Engineering Materials and Corrosion Control Southern Marine Science and Engineering Guangdong LaboratoryZhuhai 519080China Tohoku University Sendai 980-8579Japan

Normal titanium oxycarbide exhibits an excellent electrical conductivity and a high carrier concentration of approximately 10^(21) cm^(-3);however,the low Seebeck coefficient limits the thermoelectric *** this study,first-principle calculations demonstrate that the metal vacancy of titanium oxycarbide weakens the density of state passing through the valence band at the Fermi level,impairing the carrier concentration and enhancing carrier *** analysis justifies the formation of titanium oxycarbide with metal vacancy through solid-state *** electron microscopic images demonstrate the segregation of metal vacancy based on the observation of the defect-rich and single-crystal face-centered cubic *** vacancy triggers the formation of vacancy-rich and single-crystal face-centered cubic *** aggregation of metal vacancy leads to the formation of the vacancy-rich region and other regions with a semi-coherent interface,suppressing the carrier concentration from 1.71×10^(21) to 4.5×10^(20) cm^(-3) and resulting in the Seebeck coefficient from -11μV/K of TiC_(0.5)O_(0.5) to -64μV/K at 1073 ***,vacancies accelerate electron migration from 1.65 to 4.22 cm^(-2)·V^(-1)·s^(-1),maintaining high *** figure of merit(ZT)increases more than five orders of magnitude via the introduction of metal vacancy,with the maximum figure of 2.11×10^(-2) at 1073 *** results indicate the potential thermoelectric application of metal-oxycarbide materials through vacancy engineering.

关键词： titanium oxycarbide metal vacancy thermoelectric first-principle calculation thermodynamics

Stress redistribution in multi-stage hydraulic fracturing of horizontal wells in shales

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Petroleum Science 2015年第4期12卷 628-635页

作者： Yi-Jin Zeng Xu zhang bao-Ping zhang Sinopec Research Institute of Petroleum Engineering

Multi-stage hydraulic fracturing of horizontal wells is the main stimulation method in recovering gas from tight shale gas reservoirs, and stage spacing deter- mination is one of the key issues in fracturing design. The initiation and propagation of hydraulic fractures will cause stress redistribution and may activate natural fractures in the reservoir. Due to the limitation of the analytical method in calculation of induced stresses, we propose a numerical method, which incorporates the interaction of hydraulic fractures and the wellbore, and analyzes the stress distri- bution in the reservoir under different stage spacing. Simulation results indicate the following：（1） The induced stress was overestimated from the analytical method because it did not take into account the interaction between hydraulic fractures and the horizontal wellbore. （2） The hydraulic fracture had a considerable effect on the redis- tribution of stresses in the direction of the horizontal wellbore in the reservoir. The stress in the direction per- pendicular to the horizontal wellbore after hydraulic frac- turing had a minor change compared with the original in situ stress. （3） Stress interferences among fractures were greatly connected with the stage spacing and the distance from the wellbore. When the fracture length was 200 m, and the stage spacing was 50 m, the stress redistribution due to stage fracturing may divert the original stress pat- tern, which might activate natural fractures so as to generate a complex fracture network.

关键词： Shale gas - Horizontal well Multi-stagefracturing Complex fracture Stage spacing - Inducedstress

Design of on-chip 15-18 GHz ultra low noise amplifier

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The Journal of China Universities of Posts and Telecommunications 2014年第4期21卷 15-18,31页

作者： GAO Yuan zhang bao-jun zhang Bo School of Electronic Engineering Xi'an University of Posts and Telecommunications

With rapid development communication system, high signal to noise ratio （SNR） system is required. In high frequency bandwidth, high loss, low Q inductors and high noise figure is a significant challenge with on-chip monolithic microwave integrated circuits （MMICs）. To overcome this problem, high Q, low loss transmission line characteristics was analyzed. Compared with the same inductor value of the lumped component and the transmission line, it has a higher Q value and lower loss performance in high frequency, and a 2-stage common-source low noise amplifier （LNA） was presented, which employs source inductor feedback technology and high Q low loss transmission line matching network technique with over 17.6 dB small signal gain and 1.1 dB noise figure in 15 GHz-18 GHz. The LNA was fabricated by WIN semiconductors company 0.15 μm gallium arsenide （GaAs） P high electron mobility transistor （P-HEMT） process. The total Current is 15 mA, while the DC power consumption is only 45 mW.

关键词： LNA GAAS P-HEMT MMIC K-bAND

Metabolic and transcriptomic analyses elucidate a novel insight into the network for biosynthesis of carbohydrate and secondary metabolites in the stems of a medicinal orchid Dendrobium nobile

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Plant Diversity 2023年第3期45卷 326-336页

作者： Yu-Wen zhang Yu-Cen Shi Shi-bao zhang Key Laboratory of Economic Plants and Biotechnology Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina Yunnan Key Laboratory for Wild Plant Resources Kunming 650201YunnanChina University of Chinese Academy of Sciences Beijing 100049China Lijiang Forest Biodiversity National Observation and Research Station Kunming Institute of BotanyChinese Academy of SciencesLijiang 674100YunnanChina

Dendrobium nobile is an important medicinal and nutraceutical *** the ingredients of *** have been identified as polysaccharides,alkaloids,amino acids,flavonoids and bibenzyls,our understanding of the metabolic pathways that regulate the synthesis of these compounds is ***,we used transcriptomic and metabolic analyses to elucidate the genes and metabolites involved in the biosynthesis of carbohydrate and several secondary metabolites in the stems of ***.A total of 1005 metabolites and 31,745 genes were detected in the stems of *** majority of these metabolites and genes were involved in the metabolism of carbohydrates(fructose,mannose,glucose,xylulose and starch),while some were involved in the metabolism of secondary metabolites(alkaloids,β-tyrosine,ferulic acid,4-hydroxybenzoate and chrysin).Our predicted regulatory network indicated that five genes(AROG,PYK,DXS,ACEE and HMGCR) might play vital roles in the transition from carbohydrate to alkaloid *** analysis identified that six genes(ALDO,PMM,BGLX,EGLC,XYLB and GLGA) were involved in carbohydrate metabolism,and two genes(ADT and CYP73A) were involved in secondary metabolite *** analyses also indicated that phosphoenol-pyruvate(PEP) was a crucial bridge that connected carbohydrate to alkaloid *** regulatory network between carbohydrate and secondary metabolite biosynthesis established will provide important insights into the regulation of metabolites and biological systems in Dendrobium species.

关键词： Dendrobium nobile Transcriptome Metabolome Polysaccharides Alkaloids Secondary metabolite biosynthesis

Observer-based Variable Universe Adaptive Fuzzy Controller Without Additional Dynamic Order

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International Journal of Automation and computing 2014年第4期11卷 418-425页

作者： Hai-Gang Guo bao-Jie zhang School of Mathematics and Statistics Henan University of Science and Technology School of Mathematics and Information Science Qujing Normal University

A high-precision fuzzy controller, based on a state observer, is developed for a class of nonlinear single-input-single-output(SISO) systems with system uncertainties and external disturbances. The state observer is introduced to resolve the problem of the unavailability of state variables. Assisted by the observer, a variable universe fuzzy system is designed to approximate the ideal control law. Being auxiliary components, a robust control term and a state feedback control term are designed to suppress the influence of the lumped uncertainties and remove the observation error, respectively. Different from the existing results, no additional dynamic order is required for the control design. All the adaptive laws and the control law are built based on the Lyapunov synthesis approach, and the signals involved in the closed-loop system are guaranteed to be uniformly ultimately bounded. Simulation results performed on Duffing forced oscillation demonstrate the advantages of the proposed control scheme.

关键词： Variable universe fuzzy system observer strictly positive real (SPR) condition dynamic order σ-modification adaptive bounding technique

Accumulated-state-error-based event-triggered sampling scheme and its application to H∞ control of sampled-data systems

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Science China(Information Sciences) 2024年第6期67卷 328-341页

作者： Xian-Ming zhang Qing-Long HAN bao-Lin zhang Xiaohua GE Dawei zhang School of Science Computingand Engineering TechnologiesSwinburne University of Technology College of Automation and Electronic Engineering Qingdao University of Science & Technology School of Mathematics Shandong University

This paper is concerned with event-triggered H∞control of sampled-data systems. Its novelties lie in three aspects:（i） A novel accumulated-state-error-based event-triggered scheme is introduced by comparing the integral of the state error from tk to t with the system state sampled at tk. This condition works well due to the fact that the so-called Zeno behaviour does not occur.（ii） A novel Lyapunov functional is constructed to establish a criterion to ensure some certain H∞performance of the closed-loop system. This Lyapunov functional is dependent on the integral of the state error involved in the event-triggered scheme.（iii） Under the event-triggered sampling scheme, suitable state-feedback controllers can be designed rather than be given a priori. Moreover, a self-triggered implementation of the proposed event-triggered sampling scheme is presented as well. Finally, a batch reactor model and an inverted pendulum system are given to demonstrate the effectiveness of the proposed method.

关键词： event-triggered sampling self-triggered implementation H ∞ control looped-functional

The Hyperspace of the Regions below Continuous Maps with the Fell Topology

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Acta Mathematica Sinica,English Series 2012年第1期28卷 57-66页

作者： Zhong Qiang YANG bao Can zhang Department of Mathematics Shantou UniversityShantou 515063P.R.China Chengyi College Jimei UniversityXiamen 361021P.R.China

For a Tychonoff space X, we use ↓USCF（X） and↓CF（X） to denote the families of the hypographs of all semi-continuous maps and of all continuous maps from X to I = [0, 1] with the subspace topologies of the hyperspace Cldf（X × I） consisting of all non-empty closed sets in X × I endowed with the Fell topology. In this paper, we shall show that there exists a homeomorphism h： ↓USCF（X） → Q = [-1, 1]^∞ such that h（↓ CF（X））： co ： {（Xn） E Q ｜ limn→ ∞ xn = O} if and only if X is a locally compact separable metrizable space and the set of isolated points is not dense in X.

关键词： Fell topology hyperspace upper semi-continuous Hilbert cube

Experimental observation on a small-scale thermoacoustic prime mover

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 205-209页

作者： JIN Tao zhang bao-sen TANG Ke bao Rui CHEN Guo-bang Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China

A miniature thermoacoustic prime mover, consuming heat to radiate sound, may be considered as a potential way of heat management in microcircuits because of its simplicity and stability. A prototype with variable resonant tube length of 10 to 25 cm was built, and experiments were carried out to observe its performance, such as onset temperature, oscillation amplitude and operating frequency. The results with atmospheric air showed that proper structures and operating conditions can make the system start an oscillation at a temperature lower than 100 ℃, which proves the feasibility of potential usage in electronic units. The influences of stack position, heat input power or tube inclination on the oscillation amplitude, onset temperature and operating frequency are also presented.

关键词： Thermoacoustics Miniaturization Onset temperature