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Unraveling role of double-exchange interaction in electrochemical water oxidation by external magnetic field

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Rare Metals 2024年第1期43卷 289-297页

作者： Jun Li Jun-Ming Li Hong Hong Dong-Xue liu qing-Qi Cao dun-Hui Wang National Laboratory of Solid State Microstructures and Jiangsu Provincial Key Laboratory for Nanotechnology Nanjing UniversityNanjing 210093China School of Electronics and Information Hangzhou Dianzi UniversityHangzhou 310018China

Double-exchange(DE) interaction plays an important role in electrocatalytic oxygen evolution reaction(OER).However,precise achievement of DE interaction often requires foreign dopants or vacancy engineering,leading to destabilization of the catalysts and deterioration of *** contrast,the utilization of environmentally friendly,contactless,and continuously adjustable magnetic fields to study the OER process is profitable to avoid aforementioned interference factors and further elucidate the direct relationship_(0.5)between DE interaction and OER ***,by using cobalt hydroxide carbonate(Co(OH)(CO_(3))·xH_(2)O,CoHC) nanostructures as a proof-of-concept study,external magnetic fields are carefully implemented to verify the role of DE interaction during water oxidation *** studies reveal that external magnetic fields effectively enhance the reaction rate of the catalyst,the overpotential decreases from 386 to 355 mV(100 mA·cm^(-2)),while Tafel slopes drastically decline from 93 to 67 mV·dec^(-1)(1.0 T).Moreover,magnetic field increment exhibits robust *** in situ Raman and impedance measurements under external field,it can be found that magnetic field promotes the electron migration between Co^(2+) and Co^(3+) in the CoHC catalysts with the assistance of DE interactions,thus boosting the OER efficiency.

关键词： Magnetic field Double-exchange(DE)interaction Electrocatalysis Oxygen evolution reaction(OER) Cobalt hydroxide carbonate

Conceptual design and configurations selection of S/H-UAVs based on Q-rung dual hesitant double layer FQFD

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Chinese Journal of Aeronautics 2024年第9期37卷 193-205页

作者： dun YANG Li liu Wencan BAI Weiyong TIAN School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

For the conceptual design phase of Unmanned Aerial Vehicles(UAVs),a process for conceptual design and configuration selection of Solar/Hydrogen powered UAVs(S/H-UAVs)is *** design requirements of S/H-UAVs were analyzed *** proposed process used Fuzzy Quality Function Deployment(FQFD)to establish logical and quantitative ***,in order to appropriately describe the hesitancy of experts while making decision,it used Q-Rung Dual Hesitant Fuzzy Sets(QRDHFS)to score the *** addition,a decision-making framework is proposed to perform a logical selection of typical layouts based on defuzzi-fication method and Technique for Order Preference by Similarity to the Ideal Solution(TOPSIS).The present process has been applied for S/*** resulting set of design requirements con-sists of three categories:Mission Requirements(MRs),Engineering Characteristics(ECs)and Tech-nical Indicators(TIs).Four typical layouts of S/H-UAVs were sorted and *** performance of four typical layouts were evaluated and the Strut-Braced Wing(SBW)with external hydrogen storage was selected as the best layout for S/H-UAVs.

关键词： Hybrid powered UAV Conceptual design Q-Rung Dual Hesitant Fuzzy Set(QRDHFS) Quality function deployment Strut-braced wing

Enhanced hydrogen evolution reaction in FePt film with remanence due to decrease in domain walls

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Rare Metals 2024年第3期43卷 1108-1115页

作者： Hong Hong Dong-Xue liu Jun Li Jun-Ming Li Li-Qian Wu Bo Yang qing-Qi Cao dun-Hui Wang National Laboratory of Solid State Microstructures Collaborative Innovation Center of Advanced MicrostructuresJiangsu Provincial Key Laboratory for NanotechnologySchool of PhysicsNanjing UniversityNanjing210093China Hangzhou Dianzi University Hangzhou310018China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Material Science and EngineeringNortheastern UniversityShenyang110819China

As an effective strategy to improve the properties of electrocatalysts,magnetic field-assisted electrocatalytic water splitting has attracted increasing attention ***,the corresponding enhancements mostly depend on the exertion of an external magnetic field during electrochemical reactions,which results in a high cost of industrial production,and makes the magnetic field manipulation of electrocatalysis become a challenging *** this work,instead of the external magnetic field,a bias magnetic field is self-supplied by the remanence state of a ferromagnetic electrocatalyst of *** to the assistance of this bias magnetic field,the FePt film in the remanence state shows the overpotential of 229 mV during hydrogen evolution reaction,which is much lower than that in its demagnetization state(283 mV).Our findings demonstrate that the remanence in ferromagnetic electrocatalysts can improve the catalytic performance,which is attributed to the decrease in domain walls.

关键词： Remanence Magnetic domains Electrocatalysis Hydrogen evolution reaction(HER)

QAAS:quick accurate auto-scaling for streaming processing

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Frontiers of Computer Science 2024年第1期18卷 5-15页

作者： Shiyuan liu Yunchun LI Hailong YANG Ming dun Chen CHEN Huaitao ZHANG Wei LI State Key Laboratory of Software Development Environment Beijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China School of Cyber Science and Technology Beihang UniversityBeijing 100191China School of Computer Science and Technology Xi’an Jiaotong UniversityXi’an 710049China

In recent years,the demand for real-time data processing has been increasing,and various stream processing systems have *** the amount of data input to the stream processing system fluctuates,the computing resources required by the stream processing job will also *** resources used by stream processing jobs need to be adjusted according to load changes,avoiding the waste of computing *** present,existing works adjust stream processing jobs based on the assumption that there is a linear relationship between the operator parallelism and operator resource consumption(e.g.,throughput),which makes a significant deviation when the operator parallelism *** paper proposes a nonlinear model to represent operator *** divide the operator performance into three stages,the Non-competition stage,the Non-full competition stage,and the Full competition *** our proposed performance model,given the parallelism of the operator,we can accurately predict the CPU utilization and operator *** with actual experiments,the prediction error of our model is below 5%.We also propose a quick accurate auto-scaling(QAAS)method that uses the operator performance model to implement the auto-scaling of the operator parallelism of the Flink *** to previous work,QAAS is able to maintain stable job performance under load changes,minimizing the number of job adjustments and reducing data backlogs by 50%.

关键词： stream processing performance model auto-scaling

Evolution of High-energy Electron Distribution in Pulsar Wind Nebulae

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Research in Astronomy and Astrophysics 2024年第7期24卷 198-214页

作者： Yi-Ming liu Hou-dun Zeng Yu-Liang Xin Si-Ming liu Yi Zhang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031China

In this paper,we analyze the spectral energy distributions of 17 powerful(with a spin-down luminosity greater than10~(35)erg s~(-1))young(with an age less than 15,000 yr)pulsar wind nebulae(PWNe)using a simple timein-dependent one-zone emission *** aim is to investigate correlations between model parameters and the ages of the corresponding PWNe,thereby revealing the evolution of high-energy electron distributions within *** findings are as follows:(1)The electron distributions in PWNe can be characterized by a double power-law with a super-exponential cutoff.(2)As PWNe evolve,the high-energy end of the electron distribution spectrum becomes harder with the index decreasing from approximately 3.5 to 2.5,while the low-energy end spectrum index remains constant near 1.5.(3)There is no apparent correlation between the break energy or cutoff energy and the age of PWNe.(4)The average magnetic field within PWNe decreases with age,leading to a positive correlation between the energy loss timescale of electrons at the break energy or the high-energy cutoff and the age of the PWN.(5)The total electron energy within PWNe remains constant near 2×10~(48)erg,while the total magnetic energy decreases with age.

关键词： radiation mechanisms non-thermal-ISM general-ISM supernova remnants-gamma-rays general

Contact engineering for temperature stability improvement of Bi-contacted MoS2 field effect transistors

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Science China(Information Sciences) 2024年第6期67卷 172-179页

作者： Zizheng liu qing ZHANG Xiaohe HUANG Chunsen liu Peng ZHOU State Key Laboratory of Integrated Chip and Systems School of MicroelectronicsZhangjiang Fudan International Innovation CenterFudan University Frontier Institute of Chip and System Shanghai Key Lab for Future Computing Hardware and SystemFudan University Shaoxin Laboratory

Semimetallic bismuth（Bi） is one of the most effective strategies for reducing the contact resistance of two-dimensional transition metal dichalcogenide field effect transistors（FETs）. However, the low melting point of Bi contact（271.5℃） limits its reliable applications. In this study, we demonstrated that the temperature stability of Bi-contacted electrodes could be improved by inserting a high-melting point semimetallic antimony（Sb） between the Bi contacting layer and the gold（Au） capping layer. The proposed Bi/Sb/Au contact electrodes tended to form a metal mixture with a continuous surface during the heating process（Voids appeared on the surface of the Bi/Au contact electrodes after heating at 120℃）. Because of the improved contacting layer formed by the semimetal Bi/Sb alloy, the fabricated Bi/Sb/Au-contacted molybdenum sulfide（MoS2） FETs with different gate lengths demonstrated higher on-state current stability after heating treatment than the Bi/Au contact. Because of the Bi/Sb/Au contact and poly（methyl methacrylate） package, the MoS2FETs demonstrated time stability of at least two months from the almost unchanged transfer characteristics. The electrical stability indicates that the insertion of semimetallic Sb is a promising technology for reliable Bi-based contact.

关键词： temperature stability semimetallic bismuth contact semimetallic antimony contact MoS$_{2}$ FETs time stability

Formation and ecological response of sand patches in the protection system of Shapotou section of the Baotou-Lanzhou railway,China

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Journal of Arid Land 2024年第2期16卷 298-313页

作者： dun Yaoquan QU Jianjun KANG Wenyan LI Minlan liu Bin WANG Tao SHAO Mei Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China College of Urban and Environmental Sciences Northwest UniversityXi'an 710100China Zhongwei Works Section of China Railway Lanzhou Bureau Group Company Limited Zhongwei 755000China

The development of bare patches typically signifies a process of ecosystem *** the protection system of Shapotou section of the Baotou-Lanzhou railway,the extensive emergence of bare sand patches poses a threat to both stability and ***,there is limited knowledge regarding the morphology,dynamic changes,and ecological responses associated with these sand ***,we analyzed the formation and development process of sand patches within the protection system and its effects on herbaceous vegetation growth and soil nutrients through field observation,survey,and indoor analysis *** results showed that sand patch development can be divided into three stages,i.e.,formation,expansion,and stabilization,which correspond to the initial,actively developing,and semi-fixed sand patches,*** average dimensions of all sand patch erosional areas were found to be 7.72 m in length,3.91 m in width,and 0.32 m in *** actively developing sand patches were the largest,and the initial sand patches were the *** the stage of formation and expansion,the herbaceous community composition changed,and the plant density decreased by more than 50.95%.Moreover,the coverage and height of herbaceous plants decreased in the erosional area and slightly increased in the depositional lobe;and the fine particles and nutrients of soils in the erosional area and depositional lobe showed a decreasing *** the stabilization phases of sand patches,the area from the inlet to the bottom of sand patches becomes initially covered with *** and 0-2 cm surface soil condition improved in the erosional area,but this improvement was not yet evident in the depositional *** such as disturbance,climate change,and surface resistance to erosion exert notable influences on the formation and dynamics of sand *** results can provide evidence for the future treatment of sand patches and the management of the pro

关键词： railway protection system sand patch morphology vegetation characteristic soil property

Preferential Formation of Ethylene via Electrocatalytic CO_(2) Reduction on Mesoporous Cu_(2)O Nanoparticles:Synergistic Effects of Pore Structure Confinement and Surface Amine

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Chinese Journal of Chemistry 2024年第16期42卷 1846-1852页

作者： Haifeng Zhang dun Li Zhifang Chen Yingying Wang Haoyu Sun Feng liu Maochang liu Yiqun Zheng Hongwen Huang School of Chemistry Chemical Engineering and MaterialsJining UniversityQufuShandong 273155China College of Materials Science and Engineering Hunan UniversityChangshaHunan 410082China Health Management Department Shandong Vocational College of Light IndustryZiboShandong 255300China International Research Center for Renewable Energy National Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiotong UniversityXi'anShaanxi 710049China

We present a facile synthetic strategy to create mesoporous Cu_(2)O nanocrystals with tunable pore structures and surface functional groups of amine derivatives for efficient and preferable electrochemical conversion of CO_(2) into *** structural characteristics of theseCu_(2)O nanocrystals can be manipulated using a set of amine derivatives,such as pyridine,4,4'-bipyridine,and hexamethylenetetramine,during the oxidative etching process of Cu nanocrystals by bubbling gaseous oxygen in N,N-dimethylformamide *** amine derivatives not only serve as surface functional groups but also significantly affect the resulting pore *** synergistic effect of pore structure confinement and surface amine functionalization leads to the superb Faradaic efficiency(FE)of 51.9% for C_(2)H_(4),respectively,together with the C_(2)H_(4) partial current density of -209.4 mA·cm^(-2) at -0.8 V *** hydrogen electrode(RHE).The relatively high selectivity towards C_(2)H_(4) was investigated using DFT simulations,where 4,4'-bipyridine functionalized Cu_(2)O seemed to favor the C_(2)H_(4) formation with the low free energy of the *** study provides a feasible strategy to manipulate the pore structure and surface functionalization of mesoporous Cu_(2)O nanocrystals by regulating the oxidative etching process,which sheds light on the rational preparation of high-performance CO_(2)RR electrocatalysts.

关键词： Amines Ethylene Cuprous oxide CO_(2)reduction Mesoporous materials

A generalized deep neural network approach for improving resolution of fluorescence microscopy images

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Journal of Innovative Optical Health Sciences 2024年第6期17卷 53-65页

作者： Zichen Jin qing He Yang liu Kaige Wang State Key Laboratory of Cultivation Base for Photoelectric Technology and Functional Materials National Center for International Research of Photoelectric Technology&Nano-Functional Materials and ApplicationKey Laboratory of Photoelectronic Technology of Shaanxi ProvinceInstitute of Photonics and Photon-TechnologyNorthwest UniversityXi'an 710127P.R.China

Deep learning is capable of greatly promoting the progress of super-resolution imaging technology in terms of imaging and reconstruction speed,imaging resolution,and *** paper proposes a deep neural network based on a generative adversarial network(GAN).The generator employs a U-Net-based network,which integrates Dense Net for the downsampling *** proposed method has excellent properties,for example,the network model is trained with several different datasets of biological structures;the trained model can improve the imaging resolution of different microscopy imaging modalities such as confocal imaging and wide-field imaging;and the model demonstrates a generalized ability to improve the resolution of different biological structures even out of the *** addition,experimental results showed that the method improved the resolution of caveolin-coated pits(CCPs)structures from 264 nm to 138 nm,a 1.91-fold increase,and nearly doubled the resolution of DNA molecules imaged while being transported through microfluidic channels.

关键词： Deep learning super-resolution imaging generalized model framework generation adversarial networks image reconstruction.