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Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai SONG hui KANG min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back Scatter Diffraction(EBSD),Scanning Electron Microscopy(SEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

Metagenomics reveals the microbial community and functional metabolism variation in the partial nitritation-anammox process:From collapse to recovery

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Journal of Environmental Sciences 2024年第1期135卷 210-221页

作者： Hong Wang hui Gong Xiaohu Dai min Yang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China BIOMATH Department of Data Analysis and Mathematical ModellingGhent UniversityGhent 9000Belgium

Mainstream partial nitritation-anammox(PNA)process easily suffers from performance instability and even reactor collapse in ***,it is of great significance to unveil the characteristic of performance recovery,understand the intrinsic mechanism and then propose operational *** this study,we combined long-term reactor operation,batch tests,and metagenomics to reveal the succession of microbial community and functional metabolism variation from system collapse to *** aeration control(0.10-0.25mg O_(2)/L)was critical for performance *** was also found that Candidatus Brocadia became the dominant flora and its abundance increased from 3.5%to 11.0%.Significant enhancements in carbon metabolism and phospholipid biosynthesis were observed during system recovery,and the genes abundance related to signal transduction was dramatically *** up-regulation of sdh and suc genes showed the processes of succinate dehydrogenation and succinyl-CoA synthesis might stimulate the production of amino acids and the synthesis of proteins,thereby possibly improving the activity and abundance of AnAOB,which was conducive to the performance ***,the increase in abundance of hzs and hdh genes suggested the enhancement of the anammox *** in the abundance of key genes involved in nitrogen metabolism indicated that nitrogen removal pathway was more diverse after system *** achievement of performance recovery was driven by anammox,nitrification and denitrification coupled with dissimilatory nitrate reduction to *** results provide deeper insights into the recovery mechanism of PNA system and also provide a potential regulation strategy for the stable operation of the mainstream PNA process.

关键词： Partial nitritation-anammox Metagenomics Microbial community Functional metabolism Recovery

Moderate Deviations for Parameter Estimation in the Fractional Ornstein–Uhlenbeck Processes with Periodic Mean

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1308-1324页

作者： hui JIANG Shi min LI Wei Gang WANG School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China The People's Bank of China Operations Ofice of Nanjing Branch Nanjing 210016P.R.China School of Statistics and Mathematics Zhejiang Gongshang UniversityHangzhou 310018P.R.China

In this paper,we study the asymptotic properties for the drift parameter estimators in the fractional Ornstein-Uhlenbeck process with periodic mean function and long range *** Cremér-type moderate deviations,as well ... 详细信息

关键词： Cramér-type moderate deviation fractional Ornstein-Uhlenbeck process parameter estimation multiple Wiener-Ito integrals

Structure and 2p decay mechanism of^(18)Mg

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Nuclear Science and Techniques 2024年第6期35卷 145-154页

作者： Long Zhou De-Qing Fang Si-min Wang hui Hua Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics NSFC and Fudan UniversityShanghai 200438China School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China

The recently discovered,extremely proton-rich nuclide 18 Mg exhibits ground-state decay via two sequential two-proton(2p)emissions through the intermediate nucleus,*** study investigates the structure and the initial 2p decay mechanism of^(18)Mgby examining the density and correlations of the valence protons using a three-body Gamow coupled-channel *** results show that the ground state of^(18)Mgis significantly influenced by the continuum,resulting in a significant s-wave ***,based on the current framework,this does not lead to a significant deviation in mirror symmetry in either the structure or spectroscopy of the 18Mg-18C ***,the time evolution analysis of the^(18)Mgground state suggests a simultaneous 2p emission during the first step of *** observed nucleon-nucleon correlations align with those of the light-mass 2p emitters,indicating a consistent decay behavior within this nuclear region.

关键词： Structure of^(18)Mg Two-proton decay Proton-proton correlation

Identification of Early Warning Signals of Infectious Diseases in Hospitals by Integrating Clinical Treatment and Disease Prevention

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Current Medical Science 2024年第2期44卷 273-280页

作者： Lei ZHANG min-ye LI Chen ZHI min ZHU hui MA Sixth Medical Center Chinese PLA General HospitalBeijing100048China The Nursing Department Chinese PLA General HospitalBeijing 100853China

The global incidence of infectious diseases has increased in recent years,posing a significant threat to human *** typically serve as frontline institutions for detecting infectious ***,accurately identifying warning signals of infectious diseases in a timely manner,especially emerging infectious diseases,can be ***,there is a pressing need to integrate treatment and disease prevention data to conduct comprehensive analyses aimed at preventing and controlling infectious diseases within *** paper examines the role of medical data in the early identification of infectious diseases,explores early warning technologies for infectious disease recognition,and assesses monitoring and early warning mechanisms for infectious *** propose that hospitals adopt novel multidimensional early warning technologies to mine and analyze medical data from various systems,in compliance with national strategies to integrate clinical treatment and disease ***,hospitals should establish institution-specific,clinical-based early warning models for infectious diseases to actively monitor early signals and enhance preparedness for infectious disease prevention and control.

关键词： infectious disease disease prevention and control medical data warning signals

Membrane-less MoO_(3-x)@TiO_(2)-bromine battery with excellent rate capability and cyclic stability

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Journal of Energy Chemistry 2024年第6期93卷 316-321,I0008页

作者： Wenjie Huang hui Wang Bin Yuan Liuzhang Ouyang Lichun Yang min Zhu School of Materials Science and Engineering Guangdong Provincial Key Laboratory of Advanced Energy Storage MaterialsSouth China University of TechnologyGuangzhou 510640GuangdongChina

Bromine has attracted significant attention as a cathode material for aqueous batteries due to its high reduction potential of 1.05 V(Br_(3)^(-)+2e~-■3Br~-),impressive theoretical specific capacity of 223 mA h g^(-1),and rapid reaction kinetics in the ***,searching for compatible anode materials to match with bromine has posed a challenge due to its highly corrosive *** this study,we developed oxygen-deficient MoO_(3) with TiO_(2) coating(referred to as MoO_(3-x)@TiO_(2))as an anode material to pair with a bromine cathode in static full *** oxygen deficiency contributes to enhanced electronic and protonic diffusion within the MoO_(3-x)lattice,while the TiO_(2) coating mitigates structural dissolution and proton trapping during *** MoO_(3-x)@TiO_(2) demonstrates fast charge storage kinetics and excellent resistance to bromine *** impressive compatibility between MoO_(3-x)@TiO_(2) and bromine enables the construction of membrane-less full batteries with exceptional rate capability and cyclic *** MoO_(3-x)@TiO_(2)-bromine battery achieves an energy density of70.8 W h kg^(-1)at a power density of 328.1 W kg^(-1),showcasing an impressive long-term cyclic life of 20,000 *** study provides valuable insights for the development of high-performance aqueous secondary batteries.

关键词： Molybdenum trioxide Oxygen deficiency TiO_(2)coating Compatibility Bromine-based battery

Compositional tuning of A2B7-type La0.7-xYxMg0.3Ni3.5 alloys for gaseous hydrogen storage

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Journal of Rare Earths 2024年第10期42卷 1912-1919页

作者： Junkun Du hui Wang Renheng Tang Jiangwen Liu Liuzhang Ouyang min Zhu School of Materials Science and Engineering Guangdong Engineering Technology Research Center of Advanced Energy Storage MaterialsSouth China University of Technology

Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage,as well as successful application as nickel-metal hydride batteries *** this work,Y substitution was carried out to adjust the gaseous hydrogen storage properties of A2B7-type *** results indicate a multiphase structure in the alloys comprised of the main rhombohedral Gd2Co7and PuNi3phases,with a small amount of ***,the Y substitution results in higher abundance of the *** alloy La0.42Y0.28Mg0.3Ni3.5exhibits a hydrogen storage cap acity of 1.55 wt% at 298 K and a desorption plateau pressure of 0.244 *** addition,this alloy demonstrates a stable cycle life by a capacity retention of 94.2% after 50 cycles,with the main capacity degradation occurring during the initial 20 *** work accentuates the potential of the La-Y-Mg-Ni-based superlattice alloys for applications in solid-state hydrogen storage.

关键词： A2B7-type La–Mg–Ni alloys Cycle performance Desorption plateau pressure Hydrogen storage Rare earths Y substitution

Synthesis,chemical bonding and reactivity of new medium-sized polyarsenides

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Chinese Chemical Letters 2024年第7期35卷 497-501页

作者： Xu-hui Yue Xiang-Wen Zhang hui-min He Lei Qiao Zhong-ming Sun State Key Laboratory of Element-Organic Chemistry Tianjin Key Lab for Institution Rare Earth Materials and ApplicationsSchool of Materials Science and EngineeringNankai UniversityTianjin 300350China Department of Physics Institute of Computational and Applied PhysicsTaiyuan Normal UniversityJinzhong 030619China

Gaining an understanding of the growth mechanism from single atoms to clusters and bulk materials continues to present a ***,it is important to explore the evolving trends of clusters in the structure and properties during the size *** this work,we report the synthesis and characterization of two medium-sized chain-like polyarsenic anions.[As_(21)]^(3-)represents a trimeric example of polyarsenic anion assembled through oxidative coupling of As_(7)^(3-)*** anion As_(18)^(4-)included in[As_(18)MO_(2)(CO)_(8)]^(4-)is regarded as formed by two realgar-type As_(8)subunits connected by a dinuclear AsAs *** As_(18)cluster was previously predicted by theory,and this is the first time successfully synthesized using wet chemistry ***,small-sized polyarsenides As_(2)^(2-)and As_(10)^(2-)were found in compound[K(18-crown-6)]_(3)[As_(10)]_(0.5)[As_(4){Mo(CO)_(3)}_(2)]_(0.5)·*** these,the former exhibits coordination with metal ***-crystal X-ray diffraction combined with quantum chemical calculations revealed the formation of double bonded As_(2)^(2-)stabilized by metal carbonyl *** work demonstrates a novel synthetic approach for the preparation of new polyarsenides and highlights their intriguing bonding characteristics,laying the foundation for the synthesis of such compounds and paving the way for their potential applications.

关键词： Polyarsenide Zintl anions Chain-like cluster DFT calculations AdNDP

Phase field modeling of grain stability of nanocrystalline alloys by explicitly incorporating mismatch strain

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Rare Metals 2024年第7期43卷 3370-3382页

作者： min Zhou Hong-hui Wu Yuan Wu hui Wang Xiong-Jun Liu Sui-He Jiang Xiao-Bin Zhang Zhao-Ping Lu Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083Cnina Institute for Carbon Neutrality University of Science and TechnologyBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Ab st ra ct Nanocrystalline materials exhibit unique properties due to their extremely high grain boundary(GB) ***,this high-density characteristic induces grain coarsening at elevated temperatures,thereby limiting the widespread application of nanocrystalline *** experimental observations revealed that GB segregation and second-phase pinning effectively hinder GB migration,thereby improving the stability of nanocry stalline *** this study,a mouified phase-field model that integrates mismatch strain,solute segregation and precipitation was developed to evaluate the influence of lattice misfit on the thermal stability of nanocrystalline *** simulation results indicated that introducing a suitable mismatch strain can effectively enhance the microstructural stability of nanocrystalline *** synergizing precipitation with an appropriate lattice misfit,the formation of second-phase particles in the bulk grains can be suppressed,thereby facilitating solute segregation/precipitation at the *** concentrated solute segregation and precipitation at the GBs effectively hinders grain migration,thereby preventing grain *** findings provide a new perspective on the design and regulation of nanocrystalline alloys with enhanced thermal stability.

关键词： Phase field model Mismatch strain Second-phase precipitation Grain boundary segregation Nanocrystalline alloys