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Resolution-enhanced single-pixel imaging using the Hadamard transform matrix

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Chinese Physics B 2023年第12期32卷 652-656页

作者：别书航王晨晖吕瑞兵鲍倩倩付强孟少英陈希浩 Key Laboratory of Optoelectronic Devices and Detection Technology College of PhysicsLiaoning UniversityShenyang 110036China

We propose a single-pixel imaging(SPI)method to achieve a higher-resolution image via the Hadamard transform *** traditional SPI schemes,this new method recovers images by correlating single-pixel signals with synchronized transformed patterns of Hadamard bases that are actually projected onto the digital micromirror *** transform pattern is obtained through the inverse Fourier transform of the pattern acquired by Gaussian filtering of each Hadamard basis in the frequency *** proposed scheme is based on a typical SPI experimental setup and does not add any hardware complexity,enabling the transformation of Hadamard matrices and image reconstruction through data processing ***,this approach could be considered as an alternative option for achieving fast SPI in a diffraction-limited imaging system,without the need for additional hardware.

关键词： single-pixel imaging Gaussian filtering resolution enhancement

Optimal condition analysis of target localization using multi-agents with uncertain positions

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Control Theory and Technology 2025年第1期23卷 131-144页

作者： Yi Hou Ning hao Fenghua He chen xie Yu Yao School of Aerospace Harbin Institute of TechnologyHarbin150001HeilongjiangChina

This paper delves into the problem of optimal placement conditions for a group of agents collaboratively localizing a target using range-only or bearing-only *** challenge in this study stems from the uncertainty associated with the positions of the agents,which may experience drift or disturbances during the target localization ***,we derive the Cramer-Rao lower bound(CRLB)of the target position as the primary analytical ***,we establish the necessary and sufficient conditions for the optimal placement of *** on these conditions,we analyze the maximal allowable agent position error for an expected mean squared error(MSE),providing valuable guidance for the selection of agent positioning *** analytical findings are further validated through simulation experiments.

关键词： Cramer-Rao lower bound(CRLB) Target localization Uncertain sensor position Multi-agent systems

Federated local causal structure learning

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Science China(Information Sciences) 2025年第03期68卷 110-124页

作者： Kui YU chen RONG hao WANG Fuyuan CAO Jiye LIANG School of Computer and Information Hefei University of Technology School of Computer and Information Technology Shanxi University

Local causal structure learning(LCS) efficiently identifies a set of direct neighbors of a specified variable from observational data. Additionally, it distinguishes direct causes and direct effects of this variable without learning the entire causal structure. While many LCS algorithms have been proposed, they do not consider the data privacy-preserving problem,which has attracted extensive attention from academia and industry. To address this issue, we propose a federated local causal structure learning(FedLCS) algorithm to learn local causal structures in privacy-preserving data in a federated ***, FedLCS introduces a layer-wise federated local skeleton learning algorithm to construct the local skeleton. Based on this skeleton, it introduces a federated local skeleton orientation algorithm and an extension-and-backtracking orientation algorithm to orient the edges. Finally, FedLCS uses a federated local extension-and-backtracking orientation algorithm to orient the remaining edges. Extensive experiments on benchmark, synthetic, and real datasets demonstrate that FedLCS can learn the local causal structure of a given variable in a federated setting.

关键词： local causal structure learning federated learning directed acyclic graph privacy-preserving data federated layer-wise strategy

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On the ionospheric response in the Taiwan region to Typhoon Meranti in September 2016

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Geodesy and Geodynamics 2025年第1期16卷 29-41页

作者： Peng chen Mingzhu xiong Yibin Yao hao chen Fucai Tang Liangcai Qiu Yuchen Zhang College of Geomatics Xi'an University of Science and Technology State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and Technology Chinese Academy of Science School of Geodesy and Geomatics Wuhan University Key Laboratory of Geospace Environment and Geodesy Ministry of Education Wuhan University

Previous studies have revealed that typhoons can affect the ionosphere. This paper uses GNSS observations provided by GNSS tracking stations of Taiwan region, ERA5 gravity wave dissipation products,and Himawari-8 band 07 brightness temperature observation data to analyze the impact of Typhoon Meranti on Taiwan region's ionosphere from September 13 to 15, 2016. In addition to the daily effects of traveling ionospheric disturbances(TIDs), TIDs of various intensities caused by Meranti-induced gravity waves were observed during this period, which is inseparable from the state of the typhoon and the topographic features during its progress. The ionospheric disturbance caused by the edge of a typhoon is usually larger than that at the typhoon eye. When the typhoon approached Taiwan region with high intensity on September 14, it was observed that the gravity waves caused by the typhoon had a wavelength of about 174-293 km, a period of 13.5-23.5 min, and a propagation speed of 142-302 m/s. When the vortex structure of a typhoon interacts with complex surfaces such as mountains, it is easier to excite more medium-scale gravity waves. The origin that excites gravity waves and causes ionospheric anomalies is different from the location of the typhoon eye and changes over time. The gravity waves caused by the typhoon lasted for three days in the central mountains of Taiwan region. Still, background wind conditions restricted the propagation of gravity waves from the mesosphere to the thermosphere and led to TID predominantly concentrated between 06:00 and 13:00 UT each day.

关键词： Typhoon GNSS TEC TID Gravity waves

Meteorological effects on sources and future projection of nitrogen deposition to lakes in China

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Journal of Environmental Sciences 2025年第5期151卷 100-112页

作者： cheng Shi hao Guo Xue Qiao Jingsi Gao Ying chen Hongliang Zhang Department of Biological and Ecological Engineering Oregon State UniversityCorvallisOR 97331USA State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Institute of New Energy and Low-carbon Technology Sichuan UniversityChengdu 610065China Engineering Technology Development Center of Urban Water Recycling Shenzhen PolytechnicShenzhen 518055China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan UniversityShanghai 200438China IRDR ICoE on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health Fudan UniversityShanghai 200438China

Lake ecosystems are extremely sensitive to nitrogen growth,which leads to water quality degradation and ecosystem health *** depositions,as one of the main sources of nitrogen in water,are expected to change under future climate change ***,it remains not clear how nitrogen deposition to lakes respond to future meteorological *** this study,a source-oriented version of Community Multiscale Air Quality(CMAQ)Model was used to estimate nitrogen deposition to 263 lakes in 2013 and under three RCP scenarios(4.5,6.0 and 8.5)in *** total deposition of 58.2 Gg nitrogen was predicted for all lakes,with 23.3 Gg N by wet deposition and 34.9 Gg N by dry *** and ammonium in aerosol phase are the major forms of wet deposition,while NH3 and HNO_(3)in gas phase are the major forms of dry *** emissions contribute to 57%of wet deposition and 44%of dry *** future meteorological conditions,wet deposition is predicted to increase by 5.5%to 16.4%,while dry deposition would decrease by 0.3%to 13.0%.Changes in wind speed,temperature,relative humidity(RH),and precipitation rates are correlated with dry and wet deposition *** predicted changes in deposition to lakes driven by meteorological changes can lead to significant changes in aquatic chemistry and ecosystem *** from future emission scenarios,different climate scenarios should be considered in future ecosystem health evaluation in response to nitrogen deposition.

关键词： Deposition Nitrogen Lakes CMAQ Meteorological variations

Role of iron ore in enhancing gasification of iron coke:Structural evolution,influence mechanism and kinetic analysis

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 58-69页

作者： Jie Wang Wei Wang Xuheng chen Junfang Bao Qiuyue hao Heng Zheng Runsheng Xu School of Chemistry and Materials Science Hubei Engineering UniversityXiaogan 432000China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081China Institue of Ironmaking Technology Baosteel Central Research InstituteShanghai 201999China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The utilization of iron coke provides a green pathway for low-carbon *** uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was ***,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric *** findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and *** provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron *** the heating rate in non-isothermal gasification can enhance the reactivity of iron *** metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon *** kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore ***,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.

关键词： low-carbon ironmaking iron coke gasification structural evolution kinetic model

Machine learning-based grayscale analyses for lithofacies identification of the Shahejie formation, Bohai Bay Basin, China

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Petroleum Science 2025年第1期22卷 42-54页

作者： Yu-Fan Wang Shang Xu Fang hao Hui-Min Liu Qin-Hong Hu Ke-Lai xi Dong Yang National Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Shengli Oilfield Branch Company SINOPEC

It is of great significance to accurately and rapidly identify shale lithofacies in relation to the evaluation and prediction of sweet spots for shale oil and gas reservoirs. To address the problem of low resolution in logging curves, this study establishes a grayscale-phase model based on high-resolution grayscale curves using clustering analysis algorithms for shale lithofacies identification, working with the Shahejie Formation, Bohai Bay Basin, China. The grayscale phase is defined as the sum of absolute grayscale and relative amplitude as well as their features. The absolute grayscale is the absolute magnitude of the gray values and is utilized for evaluating the material composition(mineral composition + total organic carbon) of shale, while the relative amplitude is the difference between adjacent gray values and is used to identify the shale structure type. The research results show that the grayscale phase model can identify shale lithofacies well, and the accuracy and applicability of this model were verified by the fitting relationship between absolute grayscale and shale mineral composition, as well as corresponding relationships between relative amplitudes and laminae development in shales. Four lithofacies are identified in the target layer of the study area: massive mixed shale, laminated mixed shale, massive calcareous shale and laminated calcareous shale. This method can not only effectively characterize the material composition of shale, but also numerically characterize the development degree of shale laminae, and solve the problem that difficult to identify millimeter-scale laminae based on logging curves, which can provide technical support for shale lithofacies identification, sweet spot evaluation and prediction of complex continental lacustrine basins.

关键词： Shale Machine learning Absolute grayscale Relative amplitude Grayscale phase model Lithofacies identification

Research progress of catalysts for direct coal liquefaction

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Journal of Energy Chemistry 2025年第1期100卷 481-497页

作者： Wei Song Penggao Liu xinyue chen Ting Wang Chunrong He Rui hao Kaiyu Liu State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830017XinjiangChina College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuo 454003HenanChina Hunan Provincial Key Laboratory of Chemical Power Sources College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083HunanChina

Coal direct liquefaction technology is a crucial contemporary coal chemical technology for efficient and clean use of coal resources. The development of direct coal liquefaction technology and the promotion of alternative energy sources are important measures to guarantee energy security and economic security. However, several challenges need to be addressed, including low conversion rate, inadequate oil yield, significant coking, demanding reaction conditions, and high energy consumption. Extensive research has been conducted on these issues, but further exploration is required in certain aspects such as pyrolysis of macromolecules during the liquefaction process, hydrogen activation, catalysts' performance and stability, solvent hydrogenation, as well as interactions between free radicals to understand their mechanisms better. This paper presents a comprehensive analysis of the design strategy for efficient catalysts in coal liquefaction, encompassing the mechanism of coal liquefaction, catalyst construction,and enhancement of catalytic conversion efficiency. It serves as a comprehensive guide for further research endeavors. Firstly, it systematically summarizes the conversion mechanism of direct coal liquefaction, provides detailed descriptions of various catalyst design strategies, and especially outlines the catalytic mechanism. Furthermore, it addresses the challenges and prospects associated with constructing efficient catalysts for direct coal liquefaction based on an understanding of their action mechanisms.

关键词： Direct coal liquefaction Catalysts Mechanismof action Solvent hydrogenation

Mechanistic insight into the synergy between nickel single atoms and nanoparticles on N-doped carbon for electroreduction of CO_(2)

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Journal of Energy Chemistry 2025年第1期100卷 327-336页

作者： Mingdong Sun Wenwen Guan Cailing chen Chao Wu xiaoling Liu Biao Meng Tao chen Yu Han Jun Wang Shibo xi Yu Zhou State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816JiangsuChina Advanced Membranes and Porous Materials Center Physical Sciences and Engineering DivisionKing Abdullah University of Science and TechnologyThuwal 23955-6900Saudi Arabia Institute of Sustainability for Chemicals Energy and EnvironmentA*STAR(Agency for ScienceTechnology and Research)Jurong IslandSingapore 627833Singapore College of Materials Science and Engineering Sichuan UniversityChengdu 610065SichuanChina

The synergy of single atoms(SAs)and nanoparticles(NPs)has demonstrated great potential in promoting the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR);however,the rationalization of the SAs/NPs proportion remains one challenge for the catalyst ***,a Ni2+-loaded porous poly(ionic liquids)(PIL)precursor synthesized through the free radical self-polymerization of the ionic liquid monomer,1-allyl-3-vinylimidazolium chloride,was pyrolyzed to prepare the Ni,N co-doped carbon materials,in which the proportion of Ni SAs and NPs could be facilely modulated by controlling the annealing *** catalyst Ni-NC-1000 with a moderate proportion of Ni SAs and NPs exhibited high efficiency in the electrocatalytic conversion of CO_(2)into *** Ni K-edge X-ray absorption near-edge structure(XANES)spectra and theoretical calculations were conducted to gain insight into the synergy of Ni SAs and *** charge transfer from Ni NPs to the surrounding carbon layer and then to the Ni SAs resulted in the electron-enriched Ni SAs active *** the electroreduction of CO_(2),the coexistence of Ni SAs and NPs strengthened the CO_(2)activation and the affinity towards the key intermediate of*COOH,lowering the free energy for the potential-determining*CO_(2)→*COOH step,and therefore promoted the catalysis efficiency.

关键词： Single atom catalyst Synergy effect cO2 reduction Carbon catalyst Electrocatalysis