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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 University

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 dynamics. For 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 problems. It 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

A toroidal SAW gyroscope with focused IDTs for sensitivity enhancement

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Microsystems & Nanoengineering 2024年第2期10卷 47-56页

作者： Lu Tian Haitao Zhao qiang Shen Honglong chang Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an710072China

A surface acoustic wave(SAW)gyroscope measures the rate of rotational angular velocity by exploiting a phenomenon known as the SAW gyroscope *** a gyroscope is a great candidate for application in harsh environments because of the simplification of the suspension vibration mechanism necessary for traditional microelectromechanical system(MEMS)***,for the first time,we propose a novel toroidal standing-wave-mode SAW gyroscope using focused interdigitated transducers(FIDTs).Unlike traditional SAW gyroscopes that use linear IDTs to generate surface acoustic waves,which cause beam deflection and result in energy dissipation,this study uses FIDTs to concentrate the SAW energy based on structural features,resulting in better focusing performance and increased SAW *** experimental results reveal that the sensitivity of the structure is 1.51µV/(°/s),and the bias instability is 0.77°/s,which are improved by an order of magnitude compared to those of a traditional SAW ***,the FIDT component can enhance the performance of the SAW gyroscope,demonstrating its superiority for angular velocity *** work provides new insights into improving the sensitivity and performance of SAW gyroscopes.

关键词： angular deflection gyroscope

Recent Advances in Asymmetric Structural Composites for Excellent Electromagnetic Interference Shielding: A Review

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Chinese Journal of Polymer Science 2024年第6期42卷 693-710页

作者： Ying Zhou Bai Xue Lan Xie chang-Mei Wu qiang Zheng Department of Polymer Materials and Engineering College of Materials and Metallurgy Guizhou University National Engineering Research Center for Compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane Processes State Key Laboratory of Public Big Data Guizhou University Department of Polymer Science and Engineering Zhejiang University

Since electromagnetic pollution is detrimental to human health and the environment, numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE) via designing the hierarchical structures for electromagnetic interference(EMI) shielding polymer composites. Among the plentiful structures, the asymmetric structures are currently a hot spot, principally categorizing into multi-layered, porous, fibrous, and segregated asymmetric structures, which endows the high EMI shielding performance for polymer composites incorporated with magnetic, conductive, and/or dielectric micro/nano-fillers, due to the “absorption-reflection-reabsorption” shielding mechanism. Therefore, this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties, which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G) technology.

关键词： Asymmetric structure Microano functional filler Polymer composite Electromagnetic interference shielding

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research International 2024年第4期31卷 849-860页

作者： Guang-mei Yang Cheng Yuan chang Liu qiang Wang Guang-qiang Li Yong-shun Zou Ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were *** influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was *** results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based *** TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and ***_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,*** ***_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten *** damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration

Distributed IRS-Aided DF Relaying Systems:Performance Analysis and Optimization

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China Communications 2024年第6期21卷 129-145页

作者： Sun qiang Qian Panpan Chen Xiaomin ju Jinjuan Wang jue Zhang Jiayi School of Information Science and Technology Nantong UniversityNantong 226019China Nantong Research Institute for Advanced Communication Technologies Nantong 226019China School of Electronic and Information Engineering Nantong Vocational UniversityNantong 226007China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China

Intelligent reflecting surface(IRS)is a newly emerged and promising paradigm to substantially improve the performance of wireless communications by constructing favorable communication channels via properly tuning massive reflecting *** paper considers a distributed IRS aided decode-and-forward(DF)relaying system over Nakagami-m fading *** on a tight approximation for the distribution of the received signalto-noise ratio(SNR),we first derive exact closed-form expressions of the outage probability,ergodic capacity,and energy efficiency for the considered ***,we propose the optimal IRS configuration considering the energy efficiency and pilot ***,we compare the performance between the distributed IRS-aided DF relaying and multi-IRS-only systems,and verify the analytical results by using monte carlo simulations.

关键词： configuration energy efficiency ergodic capacity intelligent reflecting surface IRS outage probability

Ag-doped Ti_(3)C_(2)T_(x) sensor:A promising candidate for lowconcentration H_(2)S gas sensing

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High Voltage 2024年第3期9卷 537-545页

作者： Fuping Zeng Xiaoxuan Feng Xiaoyue Chen Hao Qiu Yiming Yan qiang Yao ju Tang School of Electrical Engineering and Automation Wuhan UniversityWuhanChina Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy Resources WuhanChina State Grid Chengdu Electric Power Supply Company ChengduChina State Grid Chongqing Electric Power Research Institute ChongqingChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina

Trace hydrogen sulphide(H_(2)S)could reflect the severity of insulation faults in gas-insulated switchgear(GIS),therefore,accurate and fast detection of low-concentration H_(2)S is important for on-line monitoring,fault diagnosis,and state evaluation in ***-Ti_(3)C_(2)T_(x) chemiresistive-type sensors were fabricated via drop-coating with self-reduction synthesised Ag-doped Ti_(3)C_(2)T_(x).The as-prepared sensors exhibited an excel-lent sensitivity and selectivity to H_(2)S with an extremely low detection of limit of 18.57 parts per billion(ppb)at 25℃(room temperature).The response of Ag-Ti_(3)C_(2)T_(x) sensor to 10 parts per million(ppm)H_(2)S was enhanced~12 times than that of the pristine Ti_(3)C_(2)T_(x) *** compositing of Ti_(3)C_(2)T_(x) with Ag nanoparticles(NPs)enabled the fast response/recovery time for H_(2)S *** analysis found that the enhanced H_(2)S sensing performances could be attributed to chemical sensitisation,adsorbed oxygen species regulation and high Brunauer–Emmett–Teller(BET)surface *** study paves the way for Ag-Ti_(3)C_(2)T_(x) as room-temperature sensing materials to detect low-concentration H_(2)S in GIS.

关键词： insulation diagnosis attributed

Understanding the Impact of H_(2) Diffusion Energy on the Formation Efficiency of H_(2) on the Interstellar Dust Grain Surface

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Research in Astronomy and Astrophysics 2024年第9期24卷 190-198页

作者： Xiaoying Guo Wasim Iqbal qiang chang Xiao-Hu Li School of Physics and Optoeletronic Engineering Shandong University of TechnologyZibo 255000China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesUrumqi 830011China

We use microscopic Monte Carlo simulation techniques to investigate the impact of H_(2)diffusion energy on the recombination efficiency of H_(2)on interstellar dust grain surfaces under diffuse and translucent cloud *** constructed five models representing different possible conditions encountered by adsorbed H and H_(2)on interstellar dust *** implemented adsorption sites with multiple binding energies for surface species;the Encounter-Desorption mechanism was also *** study focused on silicate surfaces in diffuse clouds and water ice surfaces in translucent *** results show that the recombination efficiency of H_(2)on dust surfaces decreases as H_(2)diffusion energy *** interesting finding of this work is that considering different binding sites for H and H_(2)gives rise to multiple steady phases,during which the recombination efficiency remains constant with a change in H_(2)diffusion energy.

关键词： astrochemistry atomic processes ISM:molecules

Paleoclimatic application of spectral parameters to the eolian red clay of the Jianzha Basin,northeastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1952-1966页

作者： Chaofeng FU ju’e TIAN Xinwen XU Yougui SONG jun ZUO Feng WANG Lin CHEN Pengfei LI Xiaoke qiang The School of Earth Science and Resources Chang’an UniversityXi’an 710054China State Key Laboratory of Loess and Quaternary Geology Institute of Earth and EnvironmentCASXi’an 710061China College of Urban and Environmental Science Northwest UniversityXi’an 710069China CAS Center for Excellence in Quaternary Science and Global change Xi’an 710061China

Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and *** measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic *** obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic *** results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ^(18)O *** results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital *** parameters,such as AS1400,D1400/D1900 and D1900(where AS represents the asymmetry of the absorption peaks around1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering *** spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at~8.5 Ma and global climatic cooling at~7.2 Ma,and thus they are applicable as both regional and global paleoenvironmental indicators.

关键词： Visible/near-infrared spectroscopy Short-wave infrared spectroscopy Paleoclimatic indicators Red clay Tibetan Plateau

Enhancing volatile fatty acids production from waste activated sludge: The role of pretreatment by N,N-bis(carboxymethyl)-L-glutamate (GLDA)

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Environmental Science and Ecotechnology 2024年第5期21卷 149-157页

作者： chang Liu Lin Li Linji Xu Tanglong Zhang qiang He Xiaodong Xin Key Laboratory of the Three Gorges Reservoir Region's Eco-environment Ministry of EducationCollege of Environment and EcologyChongqing UniversityChongqing400045PR China Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan523808PR China

N,N-bis(carboxymethyl)-L-glutamate(GLDA)is an eco-friendly chelating agent that effectively extracts multivalent metal ions from waste activated sludge(WAS)flocs,which could potentially alter their ***,the effect of GLDA on the production of volatile fatty acids(VFAs)from WAS is not well ***,we demonstrate that pretreatment with GLDA at a concentration of 200 mmol per kg VSS results in a significant increase of 142%in extractable extracellular polymeric substances and enhances the total VFAs yield by 64%compared to untreated *** reveal GLDA's capability to mobilize organic-binding multivalent metal ions within sludge ***,post-pretreatment analyses showed the release of 69.1 mg L^(-1) of Ca and 109.8 mg L^(-1) of Fe ions from the flocs,leading to a more relaxed floc structure and a reduced apparent activation energy(10.6 versus 20 kJ mol1)for WAS *** dynamic simulations further demonstrate GLDA's preferential binding to Fe3þand Ca2þover Mg2þ.Our study suggests that GLDA pretreatment causes minimal disruption to reactor stability,thereby indicating the stability of microbial community *** has emerged as a viable pretreatment agent for enhancing volatile fatty acids production from waste activated sludge.

关键词： Anaerobic fermentation Pretreatment Resource recovery Multivalent metals Solubilization