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Modified constitutive models for Inconel 718 considering current density and temperature in electrically assisted forming process

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Chinese Journal of Aeronautics 2024年第2期37卷 524-540页

作者： Xuan CUI rui zhao Min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

Electrically Assisted Forming(EAF)technology has obvious advantages in material *** develop an effective constitutive model considering electrical effects,room temperature and electrically assisted quasi-static uniaxial tensile tests were conducted using ultrathin nickelbased superalloy plates with a thickness of 0.25 *** research focused on the two most widely recognized effects:the Joule thermal and the electric athermal *** mechanism of current action can be divided into two scenarios:one considering the Joule thermal effect only,and the other considering both effects *** basic constitutive models,namely the Modified-Hollomon model and the Johnson-Cook(J-C)model,were selected to be optimized through the classification of two different situations,and four optimized constitutive models were *** was found that the J-C model with simultaneous consideration of the Joule thermal effect and electric athermal effect had the best prediction effect by comparing the results of these four ***,the accuracy of the optimization model was verified by finite element simulation of the electrically assisted stretching optimization *** results show that the constitutive model can effectively predict the temperature effect caused by the Joule heat effect and the athermal effect of current on the material.

关键词： Joule heating Elastoplasticity Plastic deformation Superalloys Constitutive models

Revisit of GeV Gamma-Ray Emission from Orion B with the Fermi Large Area Telescope

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Research in Astronomy and Astrophysics 2024年第9期24卷 128-135页

作者： Wei Zeng Xiao-Na Sun rui-Zhi Yang Jia-Chun He zhao-Dong Shi ting-ting Ge Yun-Feng Liang En-Wei Liang Guangxi Key Laboratory for Relativistic Astrophysics School of Physics Science and TechnologyGuangxi UniversityNanning 530004China Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Labrotory for Research in Galaxies and Cosmology University of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China

We revisit the γ-ray emission above 300 Me V towards the massive star-forming region of Orion B by adopting14 yr observations with the Fermi Large Area Telescope and utilizing the updated software *** extended γ-ray emission region around Orion B is resolved into two components(region Ⅰ and region Ⅱ).The γ-ray spectrum of region I agrees with the predicted γ-ray spectrum assuming the cosmic ray(CR)density is the same as that of Alpha Magnetic Spectrometer(AMS-02)measured ***γ-ray emissivity of region II appears to be deficit at low energy band(E<3 GeV).Through modeling we find that CR densities exhibit a significant deficit below 20 Ge V,which may be caused by a slow diffusion inside the dense *** is probably caused by an increased magnetic field whose strength increases with the gas density.

关键词： (ISM:)cosmic rays gamma-rays:ISM (Galaxy:)open clusters and associations:individual(NGC 2023 NGC 2024 NGC 2068 and NGC 2071)

Plasma-exfoliated g-C_(3)N_(4) with oxygen doping: tailoring photocatalytic properties

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 27-39页

作者： Yuxin Li Junxin Guo rui Han zhao Wang National Engineering Research Centre of Industry Crystallization Technology School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Heteroatom doping and defect engineering have been proposed as effective ways to modulate the energy band structure and improve the photocatalytic activity of g-C_(3)N_(4). In this work, ultrathin defective g-C_(3)N_(4) was successfully prepared using cold plasma. Plasma exfoliation reduces the thickness of g-C_(3)N_(4) from 10 nm to 3 nm, while simultaneously introducing a large number of nitrogen defects and oxygen atoms into g-C_(3)N_(4). The amount of doped O was regulated by varying the time and power of the plasma treatment. Due to N vacancies, O atoms formed strong bonds with C atoms, resulting in O doping in g-C_(3)N_(4). The mechanism of plasma treatment involves oxygen etching and gas expansion. Photocatalytic experiments demonstrated that appropriate amount of O doping improved the photocatalytic degradation of rhodamine B compared with pure g-C_(3)N_(4). The introduction of O optimized the energy band structure and photoelectric properties of g-C_(3)N_(4). Active species trapping experiments revealed ·O_(2)^(–) as the main active species during the degradation.

关键词： graphitic carbon nitride cold plasma oxygen doping nitrogen defect visible-light photocatalysis

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

Examination of two-phase behaviors in porous media during pool boiling

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Science China(Technological Sciences) 2024年第6期67卷 1695-1713页

作者： ZHANG ZhiHao GUAN ShuYa WU rui zhao ChangYing School of Mechanical Engineering Shanghai Jiao Tong University

The enhancement of pool boiling heat transfer using porous media has been extensively *** the two-phase distribution and evolution in porous media are crucial to the heat transfer performance,including the critical heat flux(CHF)and heat transfer coefficient(HTC),direct observation of the two-phase flow inside the media is limited owing to the blockage of the direct view from the porous *** this study,pool boiling visualization experiments were conducted on porous samples with different throat widths in deionized *** results showed that the HTC increased with the throat ***,the growth-contraction cycle of the vapor region and the formation and drying of the wall liquid film inside the porous media were *** vapor region,including the maximum and minimum areas in the boiling cycle,was quantitatively ***,the relationship between the minimum gas-phase area and HTC peak was identified.A one-dimensional transient model was developed considering solid skeleton heat conduction,liquid film evaporation,and vapor region growth to quantitatively study the influence of heat flux on the internal two-phase *** model successfully captured the maximum gas-phase area,duration of boiling cycles,and HTC trends at specific heat *** results of this quantitative study provide insights into the internal two-phase distribution and evolution induced by pool boiling.

关键词： porous media two-phase behaviors pool boiling

Self-initiated static-dynamic state transition behavior and triggering mechanism of strain rockburst using three-dimensional discrete element method

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Underground Space 2024年第3期16卷 143-163页

作者： Yuan Qian Cheng zhao rui Wei rui Zhang Lin Huang Huiguan Chen Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China School of Engineering Tibet UniversityLhasaTibet850000China

The accurate understanding of rockburst mechanism poses a global challenge in the field of rock *** for strain rockburst,achieving self-initiated static-dynamic state transition is a crucial step in the formation of catastrophic ***,the state transition behavior and its impact on rockburst have not received sufficient attention,and are still poorly ***,this study specifically focuses on the state transition behavior,aiming to investigate its abrupt transition process and formation mechanism,and triggering effects on *** facilitate the study,a novel burst rock-surrounding rock combined laboratory test model is proposed and its effectiveness is validated through experiment ***,corresponding numerical models are established using the three-dimensional(3D)discrete element method(DEM),enabling successful simulation of static brittle failure and rockbursts of varying intensities under quasi-static displacement loading ***,through secondary development,comprehensive recording of the mechanical and energy information pertaining to the combined specimen system and its subsystems is *** a result of numerical investigation studies,the elastic rebound dynamic behavior of the surrounding rock was discovered and identified as the key factor triggering rockburst and controlling its *** impact loading on the burst rock,induced by elastic rebound,directly initiates the dynamic processes of rockburst,serving as the direct ***,the transient work and energy convergence towards the burst rock resulting from elastic rebound are recognized as the inherent cause of ***,it has been observed that a larger extent of surrounding rock leads to a stronger elastic rebound,thereby directly contributing to a more intense *** findings can provide novel theoretical insights for the exploring of rockburst mechanism and the development of monitoring and

关键词： Strain rockburst Static-dynamic state transition Self-initiation Triggering mechanism Elastic rebound Discrete element method

Broadband intelligent programmable metasurface with polarization-modulated self-adaptive electromagnetic functionality switching

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Photonics Research 2024年第7期12卷 1395-1409页

作者： XIMING LI rui XU XIAOFENG SUN YUAN zhao zhao YANG GUOHONG DU College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China

Programmable metasurfaces have received a great deal of attention due to their ability to dynamically manipulate electromagnetic(EM) waves. Despite the rapid growth, most of the existing metasurfaces require manual control to switch among different functionalities, which poses severe limitations on practical applications. Here, we put forth an intelligent metasurface that has self-adaptive EM functionality switching in broadband without human participation. It is equipped with polarization discrimination antennas(PDAs) and feedback components to automatically adjust functionalities for the different incident polarization information.

关键词： equipped adjust polarization

The Multi-parameter Test of Gravitational Wave Dispersion with Principal Component Analysis

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Research in Astronomy and Astrophysics 2024年第5期24卷 140-150页

作者： Zhi-Chu Ma rui Niu Wen zhao CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

In this work, we consider a conventional test of gravitational wave(GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity(GR)along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis(PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multiparameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.

关键词： gravitational waves-gravitation-black hole physics

Causal Analysis Between Rice Growth and Cadmium Accumulation and Transfer under Arbuscular Mycorrhizal Inoculation

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Rice science 2024年第2期31卷 226-236页

作者： zhao ting WANG Li YANG Jixian MA Fang State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

Cadmium(Cd)contamination in rice has been a serious threat to human *** investigate the effects of arbuscular mycorrhizal fungi(AMF)on the Cd translocation in rice,a controlled pot experiment was *** results indicated that AMF significantly increased rice biomass,with an increase of up to 40.0%,particularly in root biomass by up to 68.4%.Notably,the number of prominent rice individuals also increased,and their plasticity was enhanced following AMF *** led to an increase in the net photosynthetic rate and antioxidant enzyme activity of *** the AMF treatment group,the Cd concentration in the rice roots was significantly higher(19.1%‒68.0%)compared with that in the control ***,the Cd concentration in the rice seeds was lower in the AMF treatment group,indicating that AMF facilitated the sequestration of Cd in rice roots and reduced Cd accumulation in the *** coefficients varied across different treatments,suggesting that AMF inoculation reduced the direct impact of soil Cd concentration on the total Cd accumulation in *** translocation of Cd was consistently associated with simultaneous growth dilution and compensatory accumulation as a result of mycorrhizal *** study quantitatively analyzed this process through path analysis and clarified the causal relationship between rice growth and Cd transfer under the influence of AMF.

关键词： cadmium transfer dilution effect heavy metal immobilization mycorrhizal effect path analysis phenotypic plasticity