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Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： s.W.Wi Y.s.lee Department of Physics and integrative institute of Basic sciences Soongsil University

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence sensitizer Rare earths

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 reduces 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 conductivity,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)

Present status of the KsTAR superconducting Magnet system Development

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Plasma science and Technology 2004年第5期6卷 2445-2450页

作者： Keeman Kim H.K.Park K.R.Park B.s.Lim s.i.lee M.K.Kim Y.Chu W.H.Chung s.H.Baek J.Y.Cho H.Yonekawa A.Chertovskikh Y.B.Chang J.s.Kim C.s.Kim D.J.Kim N.H.song K.P.Kim Y.J.song i.s.Woo W.s.Han D.K.lee Y.K.Oh K.W.Cho J.s.Park G.s.lee H.J.lee T.K.Ko s.J.lee National NationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalNationalKorea Atomic Energy Research InstituteDaejeonRepublic of KoreaYonsei UniversitySeoulRepublic of KoreaYonsei UniversitySeoulRepublic of Korea Fusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science InstituteDaejeonRepublic of KoreaFusion R&D CenterKorea Basic Science

The mission of Korea superconducting Tokamak Advanced Research (KsTAR)project is to develop an advanced steady-state superconducting tokamak for establishing a scientificand technological basis for an attractive fusion reactor. Because one of the KsTAR mission is toachieve a steady-state operation, the use of superconducting coils is an obvious choice for themagnet system. The KsTAR superconducting magnet system consists of 16 Toroidal Field (TF) coils and14 Poloidal Field (PF) coils. internally-cooled Cable-in-Conduit Conductors (CiCC) are put into usein both the TF and PF coil systems. The TF coil system provides a field of 3.5 T at the plasmacenter and the PF coil system is able to provide a flux swing of 17 V-sec. The major achievement inKsTAR magnet-system development includes the development of CiCC, the development of a full-size TFmodel coil, the development of a coil system for background magnetic-field generation , theconstruction of a large-scale superconducting magnet and CiCC test facility. TF and PF coils are inthe stage of fabrication to pave the way for the scheduled completion of KsTAR by the end of 2006.

关键词： superconducting magnet KsTAR CiCC

superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong s.W.lee W.J.Kim Department of Materials science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy superplasticity severe plastic deformation Grain size Grain growth

A statistical study of Magnetic Flux Emergence in solar Active Regions Prior to strongest Flares

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Research in Astronomy and Astrophysics 2024年第4期24卷 147-160页

作者： Alexander s.Kutsenko Valentina i.Abramenko Andrei A.Plotnikov Crimean Astrophysical Observatory p/o NauchnyCrimea298409Russia

Using the data on magnetic field maps and continuum intensity for solar Cycles 23 and 24,we explored 100 active regions(ARs)that produced M5.0 or stronger *** focus on the presence/absence of the emergence of magnetic flux in these ARs 2-3 days before the strong flare *** found that 29 ARs in the sample emerged monotonically amidst quiet-sun.A major emergence of a new magnetic flux within a pre-existing AR yielding the formation of a complex flare-productive configuration was observed in another 24 *** 30 ARs,an insignificant(in terms of the total magnetic flux of pre-existing AR)emergence of a new magnetic flux within the pre-existing magnetic configuration was observed;for some of them the emergence resulted in a formation of a configuration with a small δ-sunspot;11 out of 100 ARs exhibited no signatures of magnetic flux emergence during the entire interval of *** six cases the emergence was in progress when the AR appeared on the Eastern limb,so that the classification and timing of emergence were not *** conclude that the recent flux emergence is not a necessary and/or sufficient condition for strong flaring of an *** flux emergence rate of flare-productive ARs analyzed here was compared with that of flare-quiet ARs analyzed in our previous *** revealed that the flare-productive ARs tend to display faster emergence than the flare-quiet ones do.

关键词： sun:activity sun:flares sun:magnetic fields

Enhancing identity Protection in Metaverse-Based Psychological Counseling system

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Computers, Materials & Continua 2024年第1期78卷 617-632页

作者： Jun lee Hanna lee seong Chan lee Hyun Kwon Department of Game software Hoseo UniversityAsan-si31499Korea Yatav Enter Seoul04799Korea Department of Artificial intelligence and Data science Korea Military AcademySeoul01805Korea

Non-face-to-face psychological counseling systems rely on network technologies to anonymize information regard-ing client ***,these systems often face challenges concerning voice data leaks and the suboptimal communication of the client’s non-verbal expressions,such as facial cues,to the *** study proposes a metaverse-based psychological counseling system designed to enhance client identity protection while ensuring efficient information delivery to counselors during non-face-to-face *** proposed systemincorporates a voicemodulation function that instantlymodifies/masks the client’s voice to safeguard their ***,it employs real-time client facial expression recognition using an ensemble of decision trees to mirror the client’s non-verbal expressions through their avatar in the metaverse *** system is adaptable for use on personal computers and smartphones,offering users the flexibility to access metaverse-based psychological counseling across diverse *** performance evaluation of the proposed system confirmed that the voice modulation and real-time facial expression replication consistently achieve an average speed of 48.32 frames per second or higher,even when tested on the least powerful smartphone ***,a total of 550 actual psychological counseling sessions were conducted,and the average satisfaction rating reached 4.46 on a 5-point *** indicates that clients experienced improved identity protection compared to conventional non-face-to-face metaverse counseling ***,the counselor successfully addressed the challenge of conveying non-verbal cues from clients who typically struggled with non-face-to-face psychological *** proposed systemholds significant potential for applications in interactive discussions and educational activities in the metaverse.

关键词： Metaverse counseling system face tracking identity protection

Pyrometallurgical recycling of end-of-life lithium-ion batteries

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international Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1554-1571页

作者： Juheon lee Kwang Won Park il sohn sanghoon lee Department of Materials science and Engineering Seoul 03722Korea Yonsei industry Cooperation Center Yonsei UniversitySeoul 03722Korea RD solution Wanju gunJeollabuk do 55365Korea

The global importance of lithium-ion batteries(LiBs)has been increasingly underscored with the advancement of high-performance energy storage ***,the end-of-life of these batteries poses significant challenges from environmental,economic,and resource management *** review paper focuses on the pyrometallurgy-based recycling process of lithium-ion batteries,exploring the fundamental understanding of this process and the importance of its *** on the high energy consumption and emission gas issues of the pyrometallurgical recycling process,we systematically analyzed the capital-intensive nature of this process and the resulting technological ***,we conducted an in-depth discussion on the future research directions to overcome the existing technological barriers and *** review will provide valuable insights for researchers and industry stakeholders in the battery recycling field.

关键词： spent lithium-ion batteries recycling sustainability lithium valuable metal

Enhancement of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： i.sardar M.D.Hossain M.s.sikder M.N.i.Khan M.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Department of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Department ofComputer science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh Material science Division Atomic Energy CentreDhaka1000Bangladesh

spinel cubic ferrites have huge applications in me mory and high frequency *** the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important *** article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and *** X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTiR),field emission scanning electron microscopy(FEsEM),energy dispersive X-ray(EDX),vibrating sample magnetometer(VsM),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the *** XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped *** densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu *** FTiR analysis also proves the spinel cubic phase of the *** average grain size of the ferrites is obtained via FEsEM images,and it is increased from 121 to 198 *** analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ***,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the *** permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric *** dependent resistivity and impedance analysis also show the improved *** the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity

Regulating interfacial stability of siO_(x) anode with fluoride-abundant solid–electrolyte interphase by fluorine-functionalized additive

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Rare Metals 2024年第2期43卷 671-681页

作者： subin lee Taeeun Yim Advanced Batteries Laboratory Department of ChemistryIncheon National UniversityIncheon22012Republic of Korea Research institute of Basic sciences College of Natural ScienceIncheon National UniversityIncheon22012Republic of Korea

silicon oxide(siO_(x))has received remarkable attention as a next-generation battery material;however,the sudden decrease in the cycling retention constitutes a significant challenge in facilitating its ***(2,2,2-trifluoroethyl)phosphite(TTFP),which can control parasitic reactions such as the pulverization of siO_(x)anode materials and electrolyte decomposition,has been proposed to improve the lifespan of the *** electrochemical reduction of TTFP results in solid-electrolyte interphase(sEi)layers that are mainly composed of LiF,which occur at a higher potential than the working potential of the siO_(x)anode and carbonate-based *** electrolyte with TTFP exhibited a substantial improvement in cycling retention after 100 cycles,whereas the standard electrolyte showed acutely decreased *** thickness of the siO_(x)anode with TTFP also changed only slightly without any considerable delamination spots,whereas the siO_(x)anode without TTFP was prominently deformed by an enormous volume expansion with several internal *** cycled siO_(x)anode with TTFP exhibited less increase in resistance after cycling than that in the absence of TTFP,in addition to fewer decomposition adducts in corresponding X-ray photoelectron spectroscopy(XPs)analyses between the cycled siO_(x)*** results demonstrate that TTFP formed sEi layers at the siO_(x)interface,which substantially reduced the pulverization of the siO_(x)anode materials;in addition,electrolyte decomposition at the interface decreased,which led to improved cycling retention.

关键词： Lithium-ion batteries(LiBs) silicon oxide anode Electrolyte Additive solid-electrolyte interphases(sEi) Tris(2,2,2-trifluoroethyl)phosphite