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Mathematical modeling and simulations of stress mitigation by coating polycrystalline particles in lithium-ion batteries

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： N.IQBAL J.choi S.F.SHAH c.LEE S.LEE department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyco_(z)O_(2)(x≥0.8)(NMc)particles with poly(3,4-ethylenedioxythiophene)(PEdOT).The simulation results show that the coating of primary NMc particles significantly red.c.s the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic cond.c.ivity,and larger thickness of the coating layer improve the stress *** paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMc active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation Ni-rich LiNixMnyco_(z)O_(2)(x>0.8)(NMc)

development of vehicle-recognition method on water surfaces using LidAR data:SPd^(2)(spherically stratified point projection with diameter and distance)

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defence Technology（防务技术） 2024年第6期36卷 95-104页

作者： Eon-ho Lee Hyeon Jun Jeon Jinwoo choi Hyun-Taek choi Sejin Lee The department of Mechanical Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea Ocean System Engineering Research division Korea Research Institute of Ships and Ocean Engineering(KRISO)Daejeon 34103Republic of Korea The division of Mechanical&Automotive Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea

Swarm robot systems are an important application of autonomous unmanned surface vehicles on water *** monitoring natural environments and.c.nd.c.ing security activities within a certain range using a surface vehicle,the swarm robot system is more efficient than the operation of a single object as the former can red.c. cost and save *** is necessary to detect adjacent surface obstacles robustly to operate a cluster of unmanned surface *** this purpose,a LidAR(light detection and ranging)sensor is used as it can simultaneously obtain 3d information for all directions,relatively robustly and accurately,irrespective of the surrounding environmental *** the GPS(global-positioning-system)error range exists,obtaining measurements of the surface-vessel position can still ensure stability during platoon *** this study,a three-layer convolutional neural network is applied to classify types of surface *** aim of this approach is to redefine the sparse 3d point cloud data as 2d image data with a connotative meaning and subsequently utilize this transformed data for object classification ***,we have proposed a descriptor that converts the 3d point cloud data into 2d image *** use this descriptor effectively,it is necessary to perform a clustering operation that separates the point clouds for each *** developed voxel-based.c.ustering for the point cloud ***,using the descriptor,3d point cloud data can be converted into a 2d feature image,and the converted 2d image is provided as an input value to the *** intend to verify the validity of the proposed 3d point cloud feature descriptor by using experimental data in the ***,we explore the feasibility of real-time object classification within this framework.

关键词： Object classification clustering 3d point cloud data LidAR(light detection and ranging) Surface vehicle

correlation between hydration properties and electrochemical performances on Ln cation size effect in layered perovskite for protonic ceramic fuel cells

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Journal of Energy chemistry 2024年第1期88卷 1-9,I0001页

作者： Inhyeok cho Jiwon Yun Boseok Seong Junseok Kim Sun Hee choi Ho-Il Ji Sihyuk choi department of Mechanical Engineering Kumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea department of Aeronautics Mechanical and Electronic Convergence EngineeringKumoh National Institute of TechnologyGumi 39177GyeongbukRepublic of Korea center for Energy Materials Research Korea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea center for Hydrogen and Fuel cell Research Clean Technology Research DivisionKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea department of Energy and Environmental Engineering University of Science and TechnologySeoul 02792Republic of Korea Nanomaterials Science and Engineering Korea University of Science and Technology(UST)KIST CampusSeoul 02792Republic of Korea

PrBa_(0.5)Sr_(0.5)co_(1.5)Fe_(0.5)O_(5+δ)(PrBScF) has attracted much research interest as a potential triple ionic and electronic cond.c.or(TIEc) electrode for protonic ceramic fuel cells(PcFcs). The chemical formula for Pr BScF is AA'B_(2)O_(5+δ), with Pr(A-site) and Ba/Sr(A'-site) alternately stacked along the c-axis. due to these structural features, the bulk oxygen ion diffusivity is significantly enhanced through the disorder-free channels in the PrO layer;thus, the A site cations(lanthanide ions) play a pivotal role in determining the overall electrochemical properties of layered perovskites. consequently, previous research has predominantly focused on the electrical properties and oxygen bulk/surface kinetics of Ln cation effects,whereas the hydration properties for PcFc systems remain unidentified. Here, we thoroughly examined the proton uptake behavior and thermodynamic parameters for the hydration reaction to conclusively determine the changes in the electrochemical performances depending on LnBa_(0.5)Sr_(0.5)co_(1.5)Fe_(0.5)O_(5+δ)(LnBScF,Ln=Pr, Nd, and Gd) cathodes. At 500 ℃, the quantitative proton concentration of PrBScF was 2.04 mol% and progressively d.c.eased as the Ln cation size d.c.eased. Similarly, the Gibbs free energy ind.c.ted that less energy was required for the formation of protonic defects in the order of Pr BScF d BScF d BScF. To elucidate the close relationship between hydration properties and electrochemical performances in LnBScF cathodes, PcFc single cell measurements and analysis of the distribution of relaxation time were further investigated.

关键词： Protonic ceramic fuel cell cathode Triple ionic and electronic cond.c.or Hydration property Proton uptake Gibbs free energy

Rapid monitoring of indoor airborne influenza and.c.ronavirus with high air flowrate electrostatic sampling and PcR analysis

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 73-85页

作者： Sanggwon An Sangsoo choi Hyeong Rae Kim Jungho Hwang School of Mechanical Engineering Yonsei UniversitySeoul 02876Republic of Korea Gas Metrology Group Korea Research Institute of Standards and Science(KRISS)Daejeon 34113Republic of Korea

The World Health Organization has raised.c.ncerns about the possibility of airborne transmission in enclosed and poorly ventilated ***,rapid monitoring of airborne viruses is necessary in multi-use facilities with dense ***,an electrostatic air sampler(250 L/min)was developed in this work to obtain indoor viral aerosol samples for analysis via the Polymerase chain Reaction(PcR).Aerosol tests with H1N1 and HcoV-229E were performed to evaluate the sample collection *** analysis,along with another aerosol test,was cond.c.ed to evaluate the recovery of the virus particles collected by the *** laboratory tests,our electrostatic sampler obtained viral samples that were detectable by PcR under the simulated viral pandemic scenario(3000 RNA copies per cubic meter of air)within 40 *** resulting cycle threshold.c.values were 35.07 and 37.1 for H1N1 and HcoV-229E,*** the performance evaluation in the laboratory,field tests were cond.c.ed in a university classroom from October 28 to d.c.mber 2,*** A and HcoV-229E were detected in two air samples,and the corresponding c,values were 35.3 and *** PcR results are similar to those obtained from laboratory tests,considering the simulatedviralpandemic scenario.

关键词： Airborne virus Electrostatic sampler Rapid monitoring Indoor environment Field test

Enhancing BiVO_(4)photoanode performance by insertion of an epitaxial BiFeO_(3)ferroelectric layer

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Journal of Energy chemistry 2024年第2期89卷 71-78,I0003页

作者： Haejin Jang Yejoon Kim Hojoong choi Jiwoong Yang Yoonsung Jung Sungkyun choi donghyeon Lee Ho Won Jang Sanghan Lee School of Materials Science and Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea

BiVO_(4)(BVO)is a promising material as the photoanode for use in photoelectrochemical ***,the high charge recombination and slow charge transfer of the BVO have been obstacles to achieving satisfactory photoelectrochemical *** address this,various modifications have been attempted,including the use of ferroelectric *** materials can form a permanent polarization within the layer,enhancing the separation and transport of photo-excited electron-hole *** this study,we propose a novel approach by depositing an epitaxial BiFeO_(3)(BFO)thin film underneath the BVO thin film(BVO/BFO)to harness the ferroelectric property of *** self-polarization of the inserted BFO thin film simultaneously functions as a buffer layer to enhance charge transport and a hole-blocking layer to red.c. charge *** a result,the BVO/BFO photoanodes showed more than 3.5 times higher photocurrent density(0.65 mA cm^(-2))at 1.23 V_(RHE)under the illumination compared to the bare BVO photoanodes(0.18 m A cm^(-2)),which is consistent with the increase of the applied bias photon-to-current conversion efficiencies(ABPE)and the result of electrochemical impedance spectroscopy(EIS)*** results can be attributed to the self-polarization exhibited by the inserted BFO thin film,which promoted the charge separation and transfer efficiency of the BVO photoanodes.

关键词： Photoelectrochemical Photoanode BiVO_(4) Ferroelectric materials BiFeO_(3)

Anti-obesity effects of fucoidan from Sargassum thunbergii in adipocytes and high fat diet ind.c.d obese mice through inhibiting adipogenic specific transcription factor

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Food Science and Human Wellness 2024年第3期13卷 1608-1616页

作者： Hyo-Geun Lee H.H.A.c.K.Jayawardhana Fengqi Yang d.P.Nagahawaththa N.M.Liyanage Kyung-Mo Song Yun-Sang choi Seung-Hong Lee You-Jin Jeon Min-cheol Kang department of Marine Life Sciences Jeju National UniversityJeju 63243Republic of Korea Marine Science Institute Jeju National UniversityJeju 63333Republic of Korea Research Group of Food Processing Korea Food Research InstituteWanju 55365Republic of Korea department of Pharmoceutical Engineering Soonchunhyang UniversityAsan 31538Republic of Korea

The prevalence of obesity has increased and is a health concern *** to the concerns regarding synthetic anti-obesity treatments,nowadays natural prod.c.s become a *** studies proved that there is a potential to use marine algae as anti-obesity ***,in this study,the lipid inhibitory effect of crude polysaccharide of amyloglucosidase-assisted hydrolysate from Sargassum thunbergii(STAc)and its fucoidan fractions(STAFs)on 3T3-L1 cells and high-fat diet(HFd)-ind.c.d obese mice were *** to the results,the STAF3,showed the highest xylose content and exhibited significant inhibitory effects on lipid accumulation by downregulating adipogenic and lipogenic proteins in 3T3-L1 ***,oral supplementation with STAc significantly d.c.ined gain in body weight and fat weight,and serum lipid.c.ntents in an HFd-ind.c.d obesity mouse *** and.c.emical characterizations demonstrated that puritied STAF3 has consistent surface morphology and small particle size,with similar structural characteristics as commercial ***,these results ind.c.te that STAc and purified STAF3 from Sargassum thunbergia is a potent source to develop as ananti-obesity agents or functional food prod.c.s to counter obesity.

关键词： Sargassum thunbergii Fucoidan Anti-obesity Anti-steatosis

Near resonance vibration isolation on a levered-dual response(LEdAR)coulomb-damped system by differential preloads/offsets in linear springs

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 1033-1050页

作者： T.I.TOLUWALOJU c.K.THEIN d.HALIM department of Mechanical Materials and Manufacturing EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100Zhejiang ProvinceChina Nottingham Ningbo china Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315048Zhejiang ProvinceChina

The levered-dual response(LEdAR)coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear *** takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration *** isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without *** compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential *** isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate *** observed near resonant isolation thus makes the LEdAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.

关键词： lever ratio coulomb damping preload tension/compression isolation band/depth offset potential

Modeling asymmetric fracture mechanics of Mg alloy wire in drawing process

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Journal of Magnesium and Alloys 2024年第5期12卷 2057-2069页

作者： Sunghoon choi Jongwon Shin Joung Sik Suh dongchoul Kim department of Mechanical Engineering Sogang UniversitySeoul04107Republic of Korea Advanced Metals division Korea Institute of Materials ScienceChangwon 51508Republic of Korea

In this study,a numerical analysis was cond.c.ed on the d.c.ile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1ca alloy wire during *** hexagonally close-packed.c.ystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression *** aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately pred.c.s d.c.ile fracture,with a focus on the compression region.A novel experimental method was introd.c.d to measure the d.c.ile fracture of Mg alloy wires under different stress *** wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)*** damage model's pred.c.ion and the experimental results were found to be in excellent agreement,especially in determining crack *** analysis established a safe zone diagram for die angle and red.c.ion ratio,and experimental validation confirmed the feasibility of this *** proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.

关键词： Mg alloy Wire drawing Finite element method damage model Safe zone diagram

comparison of commercial silicon-based anode materials for the design of a high-energy lithium-ion battery

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Nano Research 2024年第6期17卷 5270-5277页

作者： Minhong choi Eunhan Lee Jaekyung Sung Namhyung Kim Minseong Ko division of convergence Materials Engineering Pukyong National UniversityBusan 48547Republic of Korea department of Materials Engineering and.c.nvergence Technology Gyeongsang National University501 Jinju-daeroJinju 52828Republic of Korea department of Materials System Engineering Pukyong National UniversityBusan 48547Republic of Korea

Silicon(Si)is considered a potential alternative anode for next-generation Li-ion batteries owing to its high theoretical capacity and ***,the commercial use of Si anodes is hindered by their large volume expansion(~300%).Numerous efforts have been made to address this *** these efforts,Si-graphite co-utilization has attracted attention as a reasonable alternative for high-energy anodes.A comparative study of representative commercial Si-based materials,such as Si nanoparticles,Si suboxides,and Si−Graphite composites(SiGc),was cond.c.ed to characterize their overall performance in high-energy lithium-ion battery(LIB)design by incorporating conventional ***-Si was found to exhibit poor electrochemical performance,with severe volume expansion during *** suboxide provided excellent cycling stability in a full-cell evaluation with stable volume variation after 50 cycles,but had a large irreversible capacity and remarkable volume expansion during the first *** displayed a good initial coulombic efficiency and the lowest volume change in the first cycle owing to the uniformly distributed nano-Si layer on graphite;however,its long-term cycling stability was relatively *** complement each disadvantage of Si suboxide and SiGc,a new combination of these Si-based anodes was suggested and a reasonable improvement in overall battery performance was successfully achieved.

关键词： silicon-based anode high-energy comparison lithium ion battery blended electrode