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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

Phase-Field Simulation of Sintering Process:A Review

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1165-1204页

作者： ming Xue min Yi State Key Laboratory ofMechanics and Control forAerospace Structures&Institute for Frontier Science&Key Laboratory for Intelligent Nano Materials and Devices of ministry of Education&College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics(NUAA)Nanjing210016China

Sintering,a well-established technique in powder metallurgy,plays a critical role in the processing of high melting point materials.A comprehensive understanding of structural changes during the sintering process is essential for effective product *** phase-field method stands out for its unique ability to simulate these structural *** its widespread application,there is a notable absence of literature reviews focused on its usage in sintering ***,this paper addresses this gap by reviewing the latest advancements in phase-field sintering models,covering approaches based on energy,grand potential,and entropy *** characteristics of various models are extensively discussed,with a specific emphasis on energy-based models incorporating considerations such as interface energy anisotropy,tensor-form diffusion mechanisms,and various forms of rigid particle motion during ***,the paper offers a concise summary of phase-field sintering models that integrate with other physical fields,including stress/strain fields,viscous flow,temperature field,and external electric *** conclusion,the paper provides a succinct overview of the entire content and delineates potential avenues for future research.

关键词： Phase-field model review sintering additive manufacturing

Highly Elastic,Bioresorbable Polymeric Materials for Stretchable,Transient Electronic Systems

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Nano-Micro Letters 2024年第6期16卷 1-13页

作者： jeong‑woong Shin Dong‑je Kim Tae‑min jang won Bae Han joong Hoon Lee Gwan‑jin Ko Seung min Yang Kaveti Rajaram Sungkeun Han Heeseok Kang jun Hyeon Lim Chan‑Hwi Eom Amay j.Bandodkar Hanul min Suk‑won Hwang KU‑KIST Graduate School of Converging Science and Technology Korea University145 Anam‑roSeongbuk‑guSeoul 02841Republic of Korea SK Hynix 2091Gyeongchung‑daeroBubal‑eupIcheon‑siGyeonggi‑do 17336Republic of Korea Hanwha Systems Co. Ltd.188Pangyoyeok‑roBundang‑guSeongnam‑siGyeonggi‑do 13524Republic of Korea Department of Electrical and Computer Engineering North Carolina State UniversityRaleighNC 27606USA Center for Advanced Self‑Powered Systems of Integrated Sensors and Technologies(ASSIST) North Carolina State UniversityRaleighNC 27606USA Department of Integrative Energy Engineering Korea University145 Anam‑roSeongbuk‑guSeoul 02841Republic of Korea Biomaterials Research Center Korea Institute of Science and Technology(KIST)5 Hwarang‑ro 14‑gilSeongbuk‑guSeoul 02792Republic of Korea Semiconductor R&D Center Samsung Electronics Co.Ltd.Hwaseong‑siGyeonggi‑do 18448Republic of Korea Center for Advanced Biomolecular Recognition Biomedical Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea

Substrates or encapsulants in soft and stretchable formats are key components for transient,bioresorbable electronic systems;however,elastomeric polymers with desired mechanical and biochemical properties are very limited compared to nontransient ***,we introduce a bioresorbable elastomer,poly(glycolide-co-ε-caprolactone)(PGCL),that contains excellent material properties including high elongation-at-break(with conducing polymers,yields stretchable,conductive composites for degradable interconnects,sensors,and actuators,which can reliably function under external *** of device components with wireless modules demonstrates elastic,transient electronic suture system with on-demand drug delivery for rapid recovery of postsurgical wounds in soft,time-dynamic tissues.

关键词： Biodegradable elastomer Conductive polymer composites Biomedical device Transient electronics

Association of daily sitting time and leisure-time physical activity with body fat among ***

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journal of Sport and Health Science 2024年第2期13卷 195-203页

作者： jingwen Liao min Hu Kellie Imm Clifton j.Holmes jie Zhu Chao Cao Lin Yang Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion Guangzhou Sport UniversityGuangzhou 510500China Scientific Research Center Guangzhou Sport UniversityGuangzhou 510500China Division of Epidemiology&Genetics Department of Population and Public Health SciencesKeck School of Medicine of the University of Southern CaliforniaLos AngelesCA 90033USA Program in Physical Therapy Washington University School of MedicineSt.LouisMO 63110USA Center for Human Nutrition Washington University School of MedicineSt.LouisMO 63110USA Department of Plastic and Reconstructive Surgery Shanghai East HospitalTongji UniversityShanghai 200070China Department of Cancer Epidemiology and Prevention Research Alberta Health ServicesCalgary T2S 3C3Canada Department of Oncology and Community Health Sciences University of CalgaryCalgary T2N 1N4Canada

Background:Prolonged sitting and reduced physical activity lead to low energy ***,little is known about the joint impact of daily sitting time and physical activity on body fat *** investigated the independent and joint associations of daily sitting time and physical activity with body fat among ***:This was a cross-sectional analysis of *** representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or *** sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity *** fat(total and trunk fat percentage)was determined via dual X-ray ***:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past *** fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both *** stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently *** the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/***:Prolonged daily sitting time was associated with increased body fat among *** higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

关键词： Adults Body fat distribution Physical activity Sitting time

An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

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journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： wen-Zhao Liu min Li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties

Normalized Solution for p-Kirchhoff Equation with a L2-supercritical Growth

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 414-429页

作者： Zhi-min REN Yong-yi LAN School of Sciences Jimei UniversityXiamen 361005China

In this paper,we investigate the following p-Kirchhoff equation{∫R^(N)|u|^(2)dx=ρ,(a+b)∫RN(|Δu}^(p)+|u|^(p))dx)(-Δpu+|u|^(p-2u)=|u|^(s-2)u+μu,x∈R^(N),where a>0,b≥0,p>0 are constants,constants,p*=N-P/Np is the critical Sobolev exponent,μis a Lagrange multiplier,-Δpu=-div(|Δu|_(p-2)u),2we demonstratethat he p-Kirchhoff equation has a normalized solution using the mountain pass lemma and some analysis techniques.

关键词： p-Kirchhoff equation normalized solution mountain-pass lemma

Probing the Kinematic Signatures of Planet Formation in the Gas Disk of MwC 480

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Research in Astronomy and Astrophysics 2024年第6期24卷 110-118页

作者： min Zhao Haochuan Yu Zhengxiang Li Department of Astronomy Beijing Normal UniversityBeijing 100875China Sub-department of Astrophysics Department of PhysicsUniversity of OxfordOxfordOX13RHUK

The disk around MwC 480 has shown multiple substructures in both dust and gas observations,possibly suggesting ongoing planet formation in *** this paper,we explore the gas kinematics of the MwC 480 disk by analyzing the archival Atacama Large Millimeter/submillimeter Array observations of^(12)CO(j=2-1),^(13)CO(j=2-1),and C^(18)O(j=2-1).By modeling the line-of-sight velocities,inferred from the Doppler shifts of the emission lines,we are able to decompose the three-dimensional(3D)velocity field of the disk into rotational,radial,and vertical *** analysis reveals the presence of large-scale gas flows in the(r,z)***,we identify potential meridional flows across various heights as traced by all three CO isotopologues in the 80–120 au region,possibly associated with ongoing planet formation activities in this ***,we find upward flows near 200 au for all three CO isotopologues,which may point to the presence of disk winds.

关键词： protoplanetary disks planet-disk interactions planet-star interactions

Quantitative Applications of weather Satellite Data for Nowcasting:Progress and Challenges

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journal of Meteorological Research 2024年第3期38卷 399-413页

作者： jun LI jing ZHENG Bo LI min min Yanan LIU Chian-Yi LIU Zhenglong LI wPaul MENZEL Timothy j.SCHMIT john L.CINTINEO Scott LINDSTROM Scott BACHMEIER Yunheng XUE Yayu MA Di DI Han LIN Innovation Centre for Fengyun Meteorological Satellite(FYSIC) National Satellite Meteorological CentreChina Meteorological AdministrationBeijing100081China School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen University and Southern Laboratory of Ocean Science and EngineeringZhuhai519082China Key Laboratory of Geographic Information Science(ministry of Education) East China Normal UniversityShanghai200241China Research Center for Environmental Changes Academia SinicaTaipei11529China Cooperative Institute for Meteorological Satellite Studies University of Wisconsin-MadisonMadisonWI53706USA Sensors and Calibration Branch STAR/NESDISMadisonWI53706USA wuxi University Wuxi214105China School of Computer Science Chengdu University of Information TechnologyChengdu610225China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing210044China Key Laboratory of Spatial Data mining and Information Sharing of ministry of Education National and Local Joint Engineering Research Center of Satellite Geospatial Information TechnologyFuzhou UniversityFuzhou350108China

Monitoring and predicting highly localized weather events over a very short-term period,typically ranging from minutes to a few hours,are very important for decision makers and public *** these events usually relies on radar observations through monitoring and *** advanced high-resolution imaging and sounding observations from weather satellites,nowcasting can be enhanced by combining radar,satellite,and other data,while quantitative applications of those data for nowcasting are advanced through using machine learning *** applications include monitoring the location,impact area,intensity,water vapor,atmospheric instability,precipitation,physical properties,and optical properties of the severe storm at different stages(pre-convection,initiation,development,and decaying),identification of storm types(wind,snow,hail,etc.),and predicting the occurrence and evolution of the *** observations can provide information on the environmental characteristics in the preconvection stage and are very useful for situational awareness and storm *** paper provides an overview of recent progress on quantitative applications of satellite data in nowcasting and its challenges,and future perspectives are also addressed and discussed.

关键词： weather satellite quantitative applications nowcasting pre-convection

Body-force modeling considering induced upstream effects for a transonic compressor with total temperature distortion

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Chinese journal of Aeronautics 2024年第6期37卷 7-19页

作者： jiahui QIU Chen YANG wenqiang ZHANG min ZHANG juan DU Digital Twin Research Center Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China School of Engineering and Science University of Chinese Academy of SciencesBeijing 100190China National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine Chinese Academy of SciencesBeijing 100190China School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

To numerically study the impact of total temperature distortion on a transonic compressor with reduced computational costs,a Body-Force Model(BFM)is ***,the interactions between the distorted flow and the compressor are analyzed using full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)results and the orbit *** is found that the induced swirl distortion and the mass flux nonuniformity are intensified in the compressor upstream flow field.A correction factor is thus added to the BFM to account for the effect of the induced swirl,which is crucial for the accurate representation of distortion transfer in the ***,steady simulations with large-amplitude 180circumferential total temperature distortion are performed using the developed *** is shown that the distorted compressor map simulated with the BFM matches well with URANS *** circumferential phase shift of total temperature and the generation of the additional total pressure distortion across the rotor are in line with the time-averaged URANS flow *** compressor upstream effects on the distorted inflow can also be exactly *** above-mentioned results demonstrate the BFM developed in this paper can effectively capture the distorted flow features inside the compressor,and significantly reduce the computational costs by five orders of magnitude compared with URANS.

关键词： Upstream effect Orbit method Induced swirl distortion Body force model Correction factor Time-averaged URANS