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Research in Astronomy and Astrophysics 2024年第7期24卷 158-169页

作者： Yining Wang Rui Sun Tianyuan Deng Chenghui zhao Peixuan zhao Jiayi Yang Peng Jia Huigen Liu Jilin Zhou College of Electronic Information and Optical Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Astronomy&Space Science Nanjing UniversityNanjing 210093China Peng Cheng Lab Shenzhen 518066China

The China Space Station Telescope(CSST)is a telescope with 2 m diameter,obtaining images with high quality through wide-field *** its first observation cycle,to capture time-domain observation data,the CSST is proposed to observe the Galactic halo across different *** data have significant potential for the study of properties of stars and ***,the density of stars in the Galactic center is high,and it is a well-known challenge to perform astrometry and photometry in such a dense star *** paper presents a deep learning-based framework designed to process dense star field images obtained by the CSST,which includes photometry,astrometry,and classifications of targets according to their light curve *** simulated CSST observation data,we demonstrate that this deep learning framework achieves photometry accuracy of 2%and astrometry accuracy of 0.03 pixel for stars with moderate brightness mag=24(i band),surpassing results obtained by traditional ***,the deep learning based light curve classification algorithm could pick up celestial targets whose magnitude variations are 1.7 times larger than magnitude variations brought by Poisson photon *** anticipate that our framework could be effectively used to process dense star field images obtained by the CSST.

关键词： techniques photometric-methods data analysis-astrometry

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bifunctional noble-metal-free cocatalyst coating enabling better coupling of photocatalytic CO_(2)reduction and H_(2)O oxidation on direct Z-scheme heterojunction

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Nano Research 2024年第6期17卷 5022-5030页

作者： Wei zhao Weihao Mo Yan Zhang Lingxuan Hu Yiyi Zheng Zhulei Chen Xiangyue Niu Yuling zhao Lichun Liu Shuxian Zhong Song bai Key Laboratory of the Ministry of Education for Advanced Catalysis Materials College of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004China College of biological Chemical Sciences and Engineering and Nanotechnology Research InstituteJiaxing UniversityJiaxing 314001China College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China College of Chemical and biological Engineering Zhejiang UniversityHangzhou 310058China School of biological and Chemical Engineering Panzhihua UniversityPanzhihua 617000China

Selective loading of spatially separated redox cocatalysts on direct Z-scheme heterojunctions holds great promise for advancing the efficiency of artificial photosynthesis,which however is limited to the photodeposition of noble metal cocatalysts and the fabrication of hollow double-shelled semiconductor ***,the co-exposure of discrete cocatalyst and semiconductor increases the product diversity when both the exposed sites of which participate in CO_(2)***,we present a facile and versatile protocol to overcome these limitations via surface coating of Z-scheme heterojunctions with bifunctional noble-metal-free *** Cu_(2)O/Fe_(2)O_(3)(CF)as a model heterojunction and layered Ni(OH)_(2)as a model cocatalyst,it is found that Ni(OH)_(2)lying on the surfaces of Cu_(2)O and Fe_(2)O_(3)separately co-catalyzes the CO_(2)reduction and H_(2)O *** experimental and theoretical investigation reveals that the Ni(OH)_(2)outer layer:(i)mitigates the charge recombination in CF and balances their transfer and consumption;(ii)reduces the rate-determining barriers for CO_(2)-to-CO and H_(2)O-to-O_(2)conversion,(iii)suppresses the side proton reduction occurring on CF,and(iv)protects the CF from component *** expected,the redox reactions stoichiometrically proceed,and significantly enhanced photocatalytic activity,selectivity,and stability in CO generation are achieved by the stacked Cu_(2)O/Fe_(2)O_(3)@Ni(OH)_(2)in contrast to *** study demonstrates the significance of the synergy between bifunctional cocatalysts and Z-scheme heterojunctions for improving the efficacy of overall redox reactions,opening a fresh avenue for the rational design of artificial photosynthetic systems.

关键词： Z-scheme heterojunction bifunctional cocatalyst CO_(2)reduction H_(2)O oxidation stoichiometric redox reaction

Dix-Type Multi-Component Scholte Wave Dispersion Inversion without Initial Model

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Journal of Earth Science 2024年第4期35卷 1393-1396页

作者： Linjing zhao Xiangchun Wang Xiaobo Liu School of Geophysics and Information Technology China University of GeosciencesBeijing 100083China Key Laboratory of Intraplate Volcanoes and Earthquakes Ministry of EducationChina University of GeosciencesBeijing 100083China School of Ocean Sciences China University of GeosciencesBeijing 100083China Key Laboratory of Polar Geology and Marine Mineral Resources Ministry of EducationChina University of GeosciencesBeijing 100083China

0 INTRODUCTION Scholte wave dispersion curves contain rich information regarding seafloor media and have therefore attracted increasing attention(Wang et al.,2022;Dong et al.,2021;Du et al.,2020).Ocean bottom seismometer(ObS)data are widely used in the study of seafloor medium information(Wang et al.,2024),and contain rich surface wave information.

关键词： seafloor wave Inversion

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Geometry characteristics and wide temperature behavior of silicon-based GaN surface acoustic wave resonators with ultrahigh quality factor

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Science China(Information Sciences) 2024年第2期67卷 267-278页

作者： Guofang YU Renrong LIANG Haiming zhao Lei XIAO Jie CUI Yue zhao Wenpu CUI Jing WANG Jun XU Jun FU Tianling REN School of Integrated Circuits Tsinghua University beijing National Research Center for Information Science Technology Tsinghua University

Surface acoustic wave(SAW) resonators with an ultrahigh Q-factor are designed and fabricated on silicon-based gallium nitride(GaN/Si). The temperature-dependent performance is characterized over a wide range, from 10 to 500 K. Finite element analysis is employed to guide the design of the SAW resonator from indications of the Rayleigh mode and weak propagation direction dependence of SAW in the c-plane of GaN/Si. The SAW resonator with 100 pairs of interdigital transducers(IDT), 100 pairs of grating reflectors(GR) for each side, aperture size of 80 μm, metallization ratio of 0.5, and electrode width of 500 nm resonates at 1.9133 GHz accordingly with an ultrahigh Q-factor of 7622 at room temperature, which contributes the fr× Qr, up to 14.583×1012Hz. A resonator operating over 10 to 500 K indicates an approximately linear decreasing temperature dependence above 280 K while being approximately constant below 40 K. The fitting to resonator characteristics using the modified butterworth Van Dyke(m bVD) model reveals a reduction in both the electrode and mechanical losses while worsening the dielectric loss with cooling down.

关键词： GaN/Si SAW resonator ultrahigh Q-factor temperature-dependent performance mbVD losses

Multivariate Time Series Anomaly Detection based on Spatial-Temporal Network and Transformer in Industrial Internet of Things

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Computers, Materials & Continua 2024年第8期80卷 2815-2837页

作者： Mengmeng zhao Haipeng Peng Lixiang Li Yeqing Ren Information Security Center State Key Laboratory ofNetworking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing100876China National Engineering Laboratory for Disaster backup and Recovery Beijing University of Posts and TelecommunicationsBeijing100876China Department of Information Science and Engineering Zaozhuang UniversityZaozhuang277160China

In the Industrial Internet of Things(IIoT),sensors generate time series data to reflect the working *** the systems are attacked,timely identification of outliers in time series is critical to ensure *** many anomaly detection methods have been proposed,the temporal correlation of the time series over the same sensor and the state(spatial)correlation between different sensors are rarely considered simultaneously in these *** to the superior capability of Transformer in learning time series *** paper proposes a time series anomaly detection method based on a spatial-temporal network and an improved ***,the methods based on graph neural networks typically include a graph structure learning module and an anomaly detection module,which are ***,in the initial phase of training,since neither of the modules has reached an optimal state,their performance may influence each *** scenario makes the end-to-end training approach hard to effectively direct the learning trajectory of each *** interdependence between the modules,coupled with the initial instability,may cause the model to find it hard to find the optimal solution during the training process,resulting in unsatisfactory *** introduce an adaptive graph structure learning method to obtain the optimal model parameters and graph *** on two publicly available datasets demonstrate that the proposed method attains higher anomaly detection results than other methods.

关键词： Multivariate time series anomaly detection spatial-temporal network Transformer

Unraveling the atomic interdiffusion mechanism of NiFe_(2_)O_(4)oxygen carriers during chemical looping CO_(2)conversion

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Carbon Energy 2024年第8期6卷 105-121页

作者： Da Song Yan Lin Shiwen Fang Yang Li Kun zhao Xinfei Chen Zhen Huang Fang He Zengli zhao Hongyu Huang Fanxing Li Guangzhou Institute of Energy Conversion Chinese Academy of SciencesGuangzhouChina School of Energy Science and Engineering University of Science and Technology of ChinaHefeiChina College of Mechanical and Electrical Engineering Zhongkai University of Agriculture and EngineeringGuangzhouChina College of Chemistry and bioengineering Guilin University of TechnologyGuilinChina North Carolina State University RaleighNorth CarolinaUSA

by employing metal oxides as oxygen carriers,chemical looping demonstrates its effectiveness in transferring oxygen between reduction and oxidation environments to partially oxidize fuels into syngas and convert CO_(2)into ***,NiFe_(2_)O_(4)oxygen carriers have demonstrated remarkable efficiency in chemical looping CO_(2)***,the intricate process of atomic migration and evolution within the internal structure of bimetallic oxygen carriers during continuous high‐temperature redox cycling remains ***,the lack of a fundamental understanding of the complex ionic migration and oxygen transfer associated with energy conversion processes hampers the design of high‐performance oxygen ***,in this study,we employed in situ characterization techniques and theoretical calculations to investigate the ion migration behavior and structural evolution in the bulk of NiFe_(2_)O_(4)oxygen carriers during H2 reduction and CO_(2)/lab air oxidation *** discovered that during the H2 reduction step,lattice oxygen rapidly migrates to vacancy layers to replenish consumed active oxygen species,while Ni leaches from the material and migrates to the *** the CO_(2)splitting step,Ni migrates toward the core of the bimetallic oxygen carrier,forming Fe–Ni *** the air oxidation step,Fe–Ni migrates outward,creating a hollow structure owing to the Kirkendall effect triggered by the swift transfer of lattice *** metal atom migration paths depend on the oxygen transfer *** discoveries highlight the significance of regulating the release–recovery rate of lattice oxygen to uphold the structures and reactivity of oxygen *** work offers a comprehensive understanding of the oxidation/reduction‐driven atomic interdiffusion behavior of bimetallic oxygen carriers.

关键词： chemical looping CO_(2)splitting density functional theory in situ characterization ionic migration

AWeb Application Fingerprint Recognition Method based on Machine Learning

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 887-906页

作者： Yanmei Shi Wei Yu Yanxia zhao Yungang Jia School of Integrated Circuit Science and Engineering Tianjin University of TechnologyTianjin300382China College of International business Zhejiang Yuexiu UniversityShaoxing312030China School of Public Administration Zhejiang Gongshang UniversityHangzhou310018China Tianjin branch of National Computer Network Emergency Response Technical Team/Coordination Center of China Tianjin300100China

Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and *** fingerprint recognition methods,which rely on preannotated feature matching,face inherent limitations due to the ever-evolving nature and diverse landscape of web *** response to these challenges,this work proposes an innovative web application fingerprint recognition method founded on clustering *** method involves extensive data collection from the Tranco List,employing adjusted feature selection built upon Wappalyzer and noise reduction through truncated SVD dimensionality *** core of the methodology lies in the application of the unsupervised OPTICS clustering algorithm,eliminating the need for preannotated *** transforming web applications into feature vectors and leveraging clustering algorithms,our approach accurately categorizes diverse web applications,providing comprehensive and precise fingerprint *** experimental results,which are obtained on a dataset featuring various web application types,affirm the efficacy of the method,demonstrating its ability to achieve high accuracy and broad *** novel approach not only distinguishes between different web application types effectively but also demonstrates superiority in terms of classification accuracy and coverage,offering a robust solution to the challenges of web application fingerprint recognition.

关键词： Web application fingerprint recognition unsupervised learning clustering algorithm feature extraction automated testing network security

Impacts of inter-satellite links on the ECOM model performance for bDS-3 MEO satellites

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Satellite Navigation 2024年第1期5卷 140-154页

作者： Chao Yang Jing Guo Xiaolong Xu Longyu Wang Qile zhao GNSS Research Center Wuhan UniversityNo.129 Luoyu RoadWuhan430079China

Inter-satellite link(ISL)plays an essential role in current and future Global Navigation Satellite System(GNSS).In this study,we investigate the impact of ISL observations on precise orbit determination for beiDou-3 Navigation Satellite System(bDS-3)Medium Earth Orbit(MEO)satellites based on different Extended CODE Orbit Models(ECOM).Thanks to the better observation geometry of the Ka-band ISL data compared to the L-band data for bDS-3 MEO satellites,the ISL solution substantially reduces Orbit boundary Discontinuity(ObD)errors,except for C30,which suffers from unstable Ka-band hardware *** the external quality analysis,ISL significantly enhances the reliability of the orbit of MEO satellites manufactured by the China Academy of Space Technology(CAST).The standard deviation(STD)of the satellite laser ranging(SLR)residuals is approximately 2.5 cm,and the root mean square(RMS)is reduced by 10–23%compared to L-band ***,the Sun-elongation angle dependent systematic error in SLR residuals nearly vanishes based on the reduced 5-parameter ECOM(ECOM1)or extended 7-parameter ECOM(ECOM2)with ISL *** is because the ISL reduces the correlation between state parameters and solar radiation pressure(SRP)parameters as well as those among SRP parameters,leading to a more accurate estimation of both orbit and SRP perturbations,particularly those along b *** confirms that the deficiency of the SRP models for bDS-3 CAST satellites can be compensated by using better observation geometry from ISL *** the other hand,for the satellite manufactured by Shanghai Engineering Center for Microsatellites(SECM),the ISL allows for a more accurate estimation of the bc_(1)parameter in the ECOM1 *** only reduces linear systematic error,possibly because the impact generated by the satellite bus cannot be entirely absorbed by the b-direction parameters.

关键词： bDS-3 MEO Inter-satellite link Solar radiation pressure ECOM

GLObAL CONVERGENCE OF A CAUTIOUS PROJECTION bFGS ALGORITHM FOR NONCONVEX PRObLEMS WITHOUT GRADIENT LIPSCHITZ CONTINUITY

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Acta Mathematica Scientia 2024年第5期44卷 1735-1746页

作者： Gonglin YUAN Xiong zhao Jiajia YU School of Mathematics and Information Science Center for Applied Mathematics of Guangxi(Guangxi University)Guangxi UniversityNanning530004China

A cautious projection bFGS method is proposed for solving nonconvex unconstrained optimization *** global convergence of this method as well as a stronger general convergence result can be proven without a gradient Lipschitz continuity assumption,which is more in line with the actual problems than the existing modified bFGS methods and the traditional bFGS *** some additional conditions,the method presented has a superlinear convergence rate,which can be regarded as an extension and supplement of bFGS-type methods with the projection ***,the effectiveness and application prospects of the proposed method are verified by numerical experiments.

关键词： cautious bFGS nonconvex problems Lipschitz continuity projection technique global convergence

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Understanding Discrepancy of Power System Dynamic Security Assessment with Unknown Faults: A Reliable Transfer Learning-based Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 427-431页

作者： Chao Ren Han Yu Yan Xu zhao Yang Dong School of Computer Science and Engineering Nanyang Technological UniversitySingapore School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore

This letter proposes a reliable transfer learning(RTL)method for pre-fault dynamic security assessment(DSA)in power systems to improve DSA performance in the presence of potentially related unknown *** takes individual discrepancies into consideration and can handle unknown faults with incomplete *** experiment results demonstrate high DSA accuracy and computational efficiency of the proposed RTL *** analysis shows RTL can guarantee system performance.

关键词： Adversarial training dynamic security assessment maximum classifier discrepancy missing data transfer learning