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Near-field wideband beam training for ELAA with uniform circular array

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Science China(Information Sciences) 2024年第6期67卷 370-383页

作者： yuhao CHEN Linglong DAI Department of Electronic Engineering Tsinghua UniversityBeijing National Research Center for Information Science and Technology (BNRist)

Extremely large-scale antenna array(ELAA) at millimeter wave(mmWave) and Terahertz(THz)band has been considered a key technology for combating high attenuation in high-frequency bands in future6G communications. Uniform circular arrays(UCAs) have attracted much attention because of their ability to provide flat beamforming gain at all angles. To realize efficient beamforming, beam training is widely used to acquire channel state information. However, with a large antenna number, the beam training overhead in ELAA systems becomes overwhelming. moreover, with a large bandwidth, the beam defocus effect severely degrades beam training accuracy. To address these issues, this paper proposes a frequency-dependent focusing(FDF)-based beam training scheme to realize effective beam training in near-field wideband ELAA systems with UCA. Specifically, we first analyze the FDF property of UCA, where signals at different subcarriers can simultaneously focus on different distances. Then, by exploiting the FDF property to search different distances using different subcarriers simultaneously, we design a hierarchical codebook and propose an FDFbased beam training scheme. To reveal the effectiveness of the proposed scheme, we compare its necessary beam training overhead with that of existing schemes. Finally, the simulation results demonstrate that the proposed scheme can achieve accurate beam training in near-field wideband UCA systems with a low beam training overhead.

关键词： extremely large-scale antenna array (ELAA) uniform circular array (UCA) near-field wideband beam training

An Azo-PDMS-based wearable UV sensor with the optimized photo response mode for dual sensing and synchronous detection

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Science China(Technological Sciences) 2022年第1期65卷 179-190页

作者： QI yuhao ZHENG JunPing Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China

A wearable UV sensor is designed to realize UV detection and a warning effect on people’s excessive UV *** is noteworthy that the photoelectric system and supporting material of the most conventional sensor are *** unstable connection between the two components and the complicated construction method makes the sensor susceptible to external motion interference and prone to ***,we developed a unique photo response mode of the UV sensor based on a novel photo responsive *** azobenzene-containing polydimethylsiloxane(Azo-PDMS)film was prepared as the outer layer of the *** integrated the functions of photo response source,support and protection,which realized the direct contact and rapid response to the UV light *** nanotube(CNT),wrapped in the middle of Azo-PDMS films as an inner layer,transformed the photomechanical response signal into the photoelectric *** photo response mode endows the sensor with excellent anti-motion interference capabilities and a true sense of UV-strain synchronous monitoring performance,which is of great significance to the practical application of wearable *** addition,based on the excellent properties of Azo-PDMS,the sensor can also protect the human body from UV damage,self-repair after fracture,and realize personalized customization through 3 D *** makes a breakthrough in the design and construction of wearable UV sensors and paves a new way to optimize sensor photo response modes.

关键词： azobenzene polydimethylsiloxane wearable UV sensor synchronous detection

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Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

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Journal of Energy Chemistry 2025年第01期 286-308页

作者： yuhao Peng Yuefeng Song Ihar Razanau Juanxiu Xiao Wei Xiao Di Hu Guoxiong Wang College of Chemistry and molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences Laboratory of Physical-Chemical Technologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key Laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of Chemical and Environmental Engineering University of Nottingham Ningbo China

Methane, an abundant one-carbon（C1） resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO2emissions and coke deposition. Electrochemical conversion of methane（ECM） using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO2emission.

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Risk-averse Contextual Multi-armed Bandit Problem with Linear Payoffs

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Journal of Systems Science and Systems Engineering 2023年第3期32卷 267-288页

作者： Yifan Lin yuhao Wang Enlu Zhou School of Industrial and Systems Engineering Georgia Institute of TechnologyAtlantaGAUSA

In this paper we consider the contextual multi-armed bandit problem for linear payoffs under a risk-averse *** each round,contexts are revealed for each arm,and the decision maker chooses one arm to pull and receives the corresponding *** particular,we consider mean-variance as the risk criterion,and the best arm is the one with the largest mean-variance *** apply the Thompson sampling algorithm for the disjoint model,and provide a comprehensive regret analysis for a variant of the proposed *** T rounds,K actions,and d-dimensional feature vectors,we prove a regret bound of O((1+ρ+1/ρ)d In T ln K/δ√dKT^(1+2∈)ln K/δ1/e)that holds with probability 1-δunder the mean-variance criterion with risk tolerance p,for any 0monstrated via a portfolio selection problem.

关键词： Multi-armed bandit context risk-averse Thompson sampling

Support Recovery of Gaussian Graphical model with False Discovery Rate Control

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Journal of Systems Science & Complexity 2023年第6期36卷 2605-2623页

作者： ZHANG yuhao LIU Yanhong WANG Zhaojun School of Mathematics and Statistics Jiangsu Normal UniversityXuzhou221116China School of Statistics and Data Science Nankai UniversityTianjin300071China

This paper focuses on the support recovery of the Gaussian graphical model(GGM)with false discovery rate(FDR)*** graceful symmetrized data aggregation(SDA)technique which involves sample splitting,data screening and information pooling is exploited via a node-based way.A matrix of test statistics with symmetry property is constructed and a data-driven threshold is chosen to control the FDR for the support recovery of *** proposed method is shown to control the FDR asymptotically under some mild *** simulation studies and a real-data example demonstrate that it yields a better FDR control while offering reasonable power in most cases.

关键词： False discovery rate Gaussian graphical model support recovery symmetrized data aggregation

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DELAY-DEPENDENT STABILITY OF LINEAR MULTISTEP METHODS FOR NEUTRAL SYSTEMS WITH DISTRIBUTED DELAYS

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Journal of Computational Mathematics 2022年第3期40卷 484-498页

作者： yuhao Cong Shouyan Wu Shanghai Customs College Shanghai 201204China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

This paper considers the asymptotic stability of linear multistep(LM)methods for neutral systems with distributed *** particular,several sufficient conditions for delay-dependent stability of numerical solutions are obtained based on the argument *** quadrature formulae are used to compute the *** algorithm is proposed to examine the delay-dependent stability of numerical *** numerical examples are performed to verify the theoretical results.

关键词： Neutral systems with distributed delays Linear multistep methods Delaydependent stability Argument principle

Skidding and spinning investigation for dry-lubricated angular contact ball bearing under combined loads

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Friction 2023年第11期11卷 1987-2007页

作者： yuhao ZHAO Zikui MA Yanyang ZI State Key Laboratory for Manufacturing and Systems Engineering Xi’an Jiaotong UniversityXi’an 710049China Schaeffler Trading(Shanghai)Co. Ltd.(Anting R&D Center)Shanghai 201804China

Sliding and spinning behaviors significantly affect the performance of rolling bearings,especially for dry-lubricated bearings,micro and macro sliding may lead to increased wear of the solid lubricating film.A unified rolling contact tribology analytical model is proposed for dry-lubricated angular contact ball bearings(ACBBs)considering the extreme conditions including high combined loads and rolling contact effects.A comprehensive solution framework is proposed to ensure the robustness of the model under different loading *** equations are solved to study the effects of friction coefficients,rotating speeds,and combined loads on the skidding and spinning characteristics of the *** results show that the rolling contact effects and combined loads significantly affect the skidding and spinning performance of the *** analysis reveals that the skidding mechanism is related to the interaction between ball kinematical motion and traction *** developed analytical model is proved to more accurately predict the bearing kinematical and tribological behavior as it discards the raceway control hypothesis and considers the macro/micro-slipping,creepage,and self-spinning motions of the ball,which is validated using both the existing pure axial loading dry-lubricated ACBB model and the classical Jones–Harris *** study would provide some guidance for the structure and lubrication design of dry-lubricated ACBBs.

关键词： angular contact ball bearing dry lubrication rolling contact skidding spinning

Topological magnetoelectric response in ferromagnetic axion insulators

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National Science Review 2024年第2期11卷 8-14页

作者： yuhao Wan Jiayu Li Qihang Liu Department of Physics and Shenzhen Institute for Quantum Science and Engineering(SIQSE) Southern University of Science and Technology Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Guangdong Provincial Key Laboratory for Computational Science and Material Design Southern University of Science and Technology

The topological magnetoelectric effect （TME） is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface ***,we theoretically propose that axion insulators with a simple ferromagnetic configuration,such as the MnBi2Te4/（Bi2Te3）nfamily,provide an ideal playground to realize the *** the designed triangular prism geometry,all the surface states are magnetically *** a vertical electric field,the surface Hall currents give rise to a nearly half-quantized orbital moment,accompanied by a gapless chiral hinge mode circulating in ***,the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric *** work paves the way for direct observation of the TME in realistic axion-insulator materials.

关键词： topological magnetoelectric effect axion insulator magnetic topological materials

Static output feedback stabilization for second-order singular systems using model reduction methods

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Applied Mathematics and Mechanics(English Edition) 2021年第3期42卷 457-466页

作者： Zheng WANG yuhao CONG Xiulin HU Department of Mathematics Shanghai UniversityShanghai 200444China Shanghai Customs College Shanghai 201204China Department of Mathematics and Physics Hefei UniversityHefei 230601China

In this paper,the static output feedback stabilization for large-scale unstable second-order singular systems is ***,the upper bound of all unstable eigenvalues of second-order singular systems is ***,by using the argument principle,a computable stability criterion is proposed to check the stability of secondorder singular ***,by applying model reduction methods to original systems,a static output feedback design algorithm for stabilizing second-order singular systems is presented.A simulation example is provided to illustrate the effectiveness of the design algorithm.

关键词： second-order singular system static output feedback model reduction method argument principle

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