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Metal-to-insulator transitions in 3d-band correlated oxides containing Fe compositions

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 48-59页

作者： Yiping yu yuchen Cui Jiangang He Wei Mao Jikun chen Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of EducationUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Institute of Industrial Science The University of Tokyo4-6-1 KomabaMeguro-kuTokyo 153-8505Japan

Metal-to-insulator transitions (MITs),which are achieved in 3d-band correlated transitional metal oxides,trigger abrupt variations in electrical,optical,and/or magnetic properties beyond those of conventional *** such material families,iron(Fe:3d^(6)4s^(2))-containing oxides pique interest owing to their widely tunable MIT properties,which are associated with the various valence states of *** potential electronic applications also show promise,given the large abundance of Fe on *** MIT properties triggered by critical temperature (TMIT) were reported for ReFe_(2)O_(4)(Fe^(2.5+)),ReBaFe_(2)O_(5)(Fe^(2.5+)),Fe_(3)O_(4)(Fe^(2.67+)),Re_(1/3)Sr_(2/3)FeO_(3)(Fe^(3.67+)),Re Cu_(3)Fe_(4)O_(12)(Fe^(3.75+)),and Ca_(1-x)Sr_(x)FeO_(3)(Fe^(4+))(where Re represents rare-earth elements).The common feature of MITs of these Fe-containing oxides is that they are usually accompanied by charge ordering transitions or disproportionation associated with the valence states of ***,we review the material family of Fe-containing MIT oxides,their MIT functionalities,and their respective *** the perspective of potentially correlated electronic applications,the tunability of the TMITand its resultant resistive change in Fe-containing oxides are summarized and further compared with those of other materials exhibiting MIT *** particular,we highlight the abrupt MIT and wide tunability of TMITof Fe-containing quadruple perovskites,such as Re ***,their effective material synthesis still needs to be further explored to cater to potential applications.

关键词： metal-to-insulator transitions Fe-containing oxides charge ordering charge disproportionation

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Promoted surface charge density from interlayer Zn–N_(4) configuration in carbon nitride for enhanced CO_(2) photoreduction

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Nano Research 2024年第4期17卷 2400-2409页

作者： Xianjin Shi yu Huang Gangqiang Zhu Wei Peng Meijuan chen State Key Laboratory of Loess and Quaternary Geology(SKLLQG) Key Laboratory of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Center of Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China School of Physics and Information Technology Shaanxi Normal UniversityXi’an 710062China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an 710049China

The solar-driven reduction of CO_(2) into valuable products is a promising method to alleviate global environmental problems and energy ***,the low surface charge density limits the photocatalytic conversion performance of CO_(2).Herein,a polymeric carbon nitride(PCN)photocatalyst with Zn single atoms(Zn1/CN)was designed and synthesized for CO_(2) *** results of the CO_(2) photoreduction studies show that the CO and CH_(4) yields of Zn1/CN increased fivefold,reaching 76.9 and 22.9μmol/(g·h),respectively,in contrast to the unmodified ***+plasma-etched X-ray photoelectron spectroscopy and synchrotron radiation-based X-ray absorption fine structure results reveal that Zn single atom is mainly present in the interlayer space of PCN in the Zn–N_(4) *** characterizations indicate that the interlayer Zn–N_(4) configuration can amplify light absorption and establish an interlayer charge transfer ***-assisted Kelvin probe force microscopy confirms that more photogenerated electrons are delivered to the catalyst surface through interlayer Zn–N_(4) configuration,which increases its surface charge ***,in-situ infrared spectroscopy combined with density functional theory calculation reveals that promoted surface charge density accelerates key intermediates(*COOH)conversion,thus achieving efficient CO_(2) *** work elucidates the role of internal single atoms in catalytic surface reactions,which provides important implications for the design of single-atom catalysts.

关键词： single-atom catalysts photocatalytic CO_(2)reduction interlayer modification charge transfer dynamics surface charge density

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Tuning Structural and Electronic Configuration of FeN_(4) via External S for Enhanced Oxygen Reduction Reaction

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Energy & Environmental Materials 2024年第2期7卷 93-101页

作者： Shidong Li Lixue Xia Jiantao Li Zhuo chen Wei Zhang Jiexin Zhu Ruohan yu Fang Liu Sungsik lee Yan Zhao Liang Zhou Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Foshan 528200China Chemical Sciences and Engineering Division Argonne National Laboratory9700 South Cass AvenueLemontIL 60439USA NRC(Nanostructure Research Centre) Wuhan University of TechnologyWuhan 430070China X-ray Science Division Advanced Photon SourcesArgonne National Laboratory9700 South CassAvenueLemontIL 60439USA State Key Laboratory of Silicate Materials for Architectures International School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China Hubei Longzhong Laboratory Xiangyang 441000China

The Fe-N-C material represents an attractive oxygen reduction reaction electrocatalyst,and the FeN_(4)moiety has been identified as a very competitive catalytic active *** tuning of the coordination structure of FeN_(4)has an essential impact on the catalytic ***,we construct a sulfur-modified Fe-N-C catalyst with controllable local coordination environment,where the Fe is coordinated with four in-plane N and an axial external *** external S atom affects not only the electron distribution but also the spin state of Fe in the FeN_(4)active *** appearance of higher valence states and spin states for Fe demonstrates the increase in unpaired *** the above characteristics,the adsorption and desorption of the reactants at FeN_(4)active sites are optimized,thus promoting the oxygen reduction reaction *** work explores the key point in electronic configuration and coordination environment tuning of FeN_(4)through S doping and provides new insight into the construction of M-N-C-based oxygen reduction reaction catalysts.

关键词： coordination structure electronic configuration FeN_(4)moiety oxygen reduction reaction sulfur doping

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Sound event localization and detection based on deep learning

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Journal of Systems Engineering and Electronics 2024年第2期35卷 294-301页

作者： ZHAO Dada DING Kai QI Xiaogang chen yu FENG Hailin School of Mathematics and Statistics Xidian UniversityXi’an 710071China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China

Acoustic source localization(ASL)and sound event detection(SED)are two widely pursued independent research *** recent years,in order to achieve a more complete spatial and temporal representation of sound field,sound event localization and detection(SELD)has become a very active research *** paper presents a deep learning-based multioverlapping sound event localization and detection algorithm in three-dimensional ***-Mel spectrum and generalized cross-correlation spectrum are joined together in channel dimension as input *** features are classified and regressed in parallel after training by a neural network to obtain sound recognition and localization results *** channel attention mechanism is also introduced in the network to selectively enhance the features containing essential information and suppress the useless ***,a thourough comparison confirms the efficiency and effectiveness of the proposed SELD *** experiments show that the proposed algorithm is robust to reverberation and environment and can achieve higher recognition and localization accuracy compared with the baseline method.

关键词： sound event localization and detection(SELD) deep learning convolutional recursive neural network(CRNN) channel attention mechanism

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High-resolution recognition of FOAM modes via an improved EfficientNet V2 based convolutional neural network

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Frontiers of physics 2024年第3期19卷 175-183页

作者： Youzhi Shi Zuhai Ma Hongyu chen Yougang Ke yu chen Xinxing Zhou International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and ApplicationsSchool of Physics and ElectronicsHunan Normal UniversityChangsha 410081China Key Laboratory of Hunan Province on Information Photonics and Freespace Optical Communications School of Information Science and EngineeringHunan Institute of Science and TechnologyYueyang 414006China

Vortex beam with fractional orbital angular momentum (FOAM) is the excellent candidate for improving the capacity of free-space optical (FSO) communication system due to its infinite modes. Therefore, the recognition of FOAM modes with higher resolution is always of great concern. In this work, through an improved EfficientNetV2 based convolutional neural network (CNN), we experimentally achieve the implementation of the recognition of FOAM modes with a resolution as high as 0.001. To the best of our knowledge, it is the first time this high resolution has been achieved. Under the strong atmospheric turbulence (AT) (C_(n)^(2)=10^(-15)m^(-2/3)), the recognition accuracy of FOAM modes at 0.1 and 0.01 resolution with our model is up to 99.12% and 92.24% for a long transmission distance of 2000 m. Even for the resolution at 0.001, the recognition accuracy can still remain at 78.77%. This work provides an effective method for the recognition of FOAM modes, which may largely improve the channel capacity of the free-space optical communication.

关键词： OAM free-space optical communication deep learning convolutional neural network

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Metal-to-insulator transition in platinum group compounds

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Rare Metals 2024年第8期43卷 3460-3474页

作者： yu-Xuan Xia Jian-Gang He Nuo-Fu chen Ji-Kun chen School of New Energy North China Electric Power UniversityBeijing102206China School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China Key Laboratory of Advanced Materials and Devices for PostMoore Chips(Ministry of Education) School of Materials Science and EngineeringJniversity of Science and Technology BeijingBeijing 100083China

The metal-to-insulator transition(MIT) as usually achieved in 3d-orbital transitional metal(TM) compounds opens up a new paradigm in correlated electronics via triggering abrupt variations in their transportation *** to such 3d-orbital TM compounds,the MIT within the platinum group(Pg) element compounds based on the 4d-and 5d-orbital configurations is more complicated,owing to their elevation in the spinorbit coupling and meanwhile weakened intra-atomic Coulomb *** brings in a new freedom to regulate the balance in their metallic or semiconductive orbital configurations,while their MIT properties can be potentially combined with their spintronic properties to enable new electronic ***,we review the electronic transport and MIT behaviors within the existing family of Pg-containing compounds,particularly those showing first-order MIT behaviors that can be useful in correlated *** is also hoped that summarizing the presently reported Pg-containing MIT compounds will lead to the discovery of more new material families and/or new mechanisms associated with the Pg-containing compounds showing MIT properties.

关键词： Metal-to-insulator transition Platinum group compounds Electron correlation Spin-orbital coupling

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Detecting compromised accounts caused by phone number recycling on e-commerce platforms: taking Meituan as an example

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Frontiers of Information Technology & Electronic Engineering 2024年第8期25卷 1077-1095页

作者： Min GAO Shutong chen Yangbo GAO Zhenhua ZHANG yu chen yupeng LI Qiongzan YE Xin WANG Yang chen School of Computer Science Fudan UniversityShanghai 200438China Shanghai Key Lab of Intelligent Information Processing Fudan UniversityShanghai 200438China Meituan Beijing 100005China Department of Interactive Media Hong Kong Baptist UniversityHong Kong 999077China

Phone number recycling(PNR)refers to the event wherein a mobile operator collects a disconnected number and reassigns it to a new *** has posed a threat to the reliability of the existing authentication solution for e-commerce ***,a new owner of a reassigned number can access the application account with which the number is associated,and may perform fraudulent *** solutions that employ a reassigned number database from mobile operators are costly for e-commerce platforms with large-scale ***,alternative solutions that depend on only the information of the applications are *** this work,we study the problem of detecting accounts that have been compromised owing to the reassignment of phone *** analysis on Meituan's real-world dataset shows that compromised accounts have unique statistical features and temporal *** on the observations,we propose a novel model called temporal pattern and statistical feature fusion model(TSF)to tackle the problem,which integrates a temporal pattern encoder and a statistical feature encoder to capture behavioral evolutionary interaction and significant operation *** experiments on the Meituan and IEEE-CIS datasets show that TSF significantly outperforms the baselines,demonstrating its effectiveness in detecting compromised accounts due to reassigned numbers.

关键词： Phone number recycling Neural networks E-commerce Compromised account detection

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Evaluation and attribution of trends in compound dry-hot events for major river basins in China

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Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO chengchao GUO yu TIAN Fang YANG Wenlong chen Xiaohong chen Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual *** climate change,compound dry and hot events become more frequent on a global *** paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and *** attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river *** is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze *** West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and *** the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern ***,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period

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Swelling of Spherical Polyelectrolyte Gels

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Chinese Journal of Polymer Science 2024年第9期42卷 1386-1392,I0009页

作者： Ming-yu Duan Jia-Dong chen Yi-Ming Liu Zhao-Feng Peng Guang chen Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijing 100871China

Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug *** this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt *** minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt *** compare our predictions for the swelling ratio with experimental measurements,which show excellent *** addition,we employ a finite element method to assess the applicability range of our theoretical model and *** anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.

关键词： Gels Polyelectrolytes Swelling Stimuli-responsive Electrostatic interaction Cell model

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Interregional Value-Added Tax in the Era of E-Commerce: Tax Policy Design Based on Big Data from Online Retailing

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Journal of Social Computing 2024年第1期5卷 46-57页

作者： yu chen Luwei Xiang Hu Yang School of Public Finance and Taxation Central University of Finance and EconomicsBeijing 100008China School of Management and Economics The Chinese University of Hong KongShenzhen 518172China School of Information Central University of Finance and EconomicsBeijing 100008China

The value-added tax(VAT)in China is levied and allocated based on the origin *** the background of the increasing substitution of online retail for traditional offline retail,this mechanism will exacerbate the disparity of regional tax revenue,and intensify tax competition among local ***,reconsidering the allocation mechanism of value-added tax in China can be an important policy decision,and it is influenced by various economic and social ***,we utilize large-scale retail transaction data from an e-commerce platform to measure regional disparities in retail and consumption among different regions and then reveals present tax policy results in revenue imbalance in different ***,we establish a model based on game theory to illustrate how the origin principle leads to fierce tax competition among ***,by establishing and solving tax allocation models between local governments and the central government,this study simulates and calculates the degree of revenue imbalance under different scenarios and attempts to propose policy *** results indicate that implementing the destination principle will reduce regional tax ***,adjusting the allocation ratio between the central government and local governments based on city levels is advantageous for further reducing regional tax revenue disparities.

关键词： value-added tax e-commerce destination principle origin principle

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