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Journal of Materials Science & Technology 2021年第30期89卷 24-35页

作者： jin-sung park Gi Dae park Yun Chan Kang Department of Materials Science and Engineering Korea UniversityAnam-DongSeongbuk-GuSeoul136-713Republic of Korea

Efforts have been made to develop a promising anode material with a novel composition for sodiumion batteries(SIBs).In this study,the sodium-ion storage mechanism of transition metal selenite that comprises transition metal cation coupled with two anions is *** cobalt selenite(CoSeO_(3))-carbon composite nanofibers containing numerous pores are synthesized via electrospinning *** heat treatment of the electrospun nanofibers containing selenium,CoSe_(2)nanoclusters are *** the subsequent oxidation,CoSe_(2)transformed into amorphous CoSeO_(3)and some part of carbon was oxidized into CO_(2),leaving the pores inside the *** unveil the electrochemical reaction mechanism,analytical methods including cyclic voltammetry,ex-situ X-ray photoelectron spectroscopy,ex-situ transmission electron microscopy,and in-situ electrochemical impedance spectroscopy techniques were *** on the analyses,the following conversion reaction from the second cycle onward is suggested:CoO+xSeO_(2)+(1-x)Se+4(x+1)Na^(+)+4(x+1)e~-?Co+(2x+1)Na_(2)O+Na_(2)***,the electrochemical properties of porous CoSeO_(3)-carbon composite nanofibers are analyzed in *** anode material exhibited stable cycle stability up to 200 cycles at 0.5 A g^(-1)and high rate performance up to 5 A g^(-1).

关键词： Anode materials Sodium-ion batteries Conversion reaction Metal selenite Electrospinning

Porous FeS nanofibers with numerous nanovoids obtained by Kirkendall diffusion effect for use as anode materials for sodium-ion batteries

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Nano Research 2017年第3期10卷 897-907页

作者： Jung Sang Cho jin-sung park Yun Chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea Department of Engineering Chemistry Chungbuk National University Chungbuk 361-763 Republic of Korea

Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation. The post-treatment of the as-spun Fe（acac）3-polyacrylonitrile composite nanofibers in an air atmosphere yielded hollow Fe2O3 nanofibers due to Ostwald ripening. The ultrafine Fe2O3 nanocrystals formed at the center of the fiber diffused toward the outside of the fiber via Ostwald ripening. On sulfidation, the Fe2O3 hollow nanofibers were transformed into porous FeS nanofibers, which contained numerous nanovoids. The formation of porosity in the FeS nanofibers was driven by nanoscale Kirkendall diffusion. The porous FeS nanofibers were very structurally stable and had superior sodium-ion storage properties compared with the hollow Fe2O3 nanofibers. The discharge capacities of the porous FeS nanofibers for the Ist and 150th cycles at a current density of 500 mA.g-1 were 561 and 592 mA.h-g-1, respectively. The FeS nanofibers had final discharge capacities of 456, 437, 413, 394, 380, and 353 mA-h.g-1 at current densities of 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 A.g-1, respectively.

关键词： iron sulfide sodium-ion batteries Kirkendall effect nanofibers electrospinning

Chemical and mechanical properties of stainless, environment-friendly, and nonflammable Mg alloys (SEN alloys): A review

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Journal of Magnesium and Alloys 2024年第3期12卷 841-872页

作者： Jong Un Lee Hyun Ji Kim Sang-Cheol jin Ye jin Kim Young Min Kim Bong Sun You Jun Ho Bae sung Hyuk park Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Metallurgical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Missile Research Institute Agency for Defense DevelopmentDaejeon 34060Republic of Korea

This review article provides overall understanding of stainless,environment-friendly,and nonflammable Mg alloys(SEN alloys)recently developed at the Korea Institute of Materials *** alloys are produced by adding small amounts of Ca and Y(each<1 wt%)into commercial Mg–Al based alloys,resulting in exceptional ignition and corrosion resistances and impressive mechanical *** main advantages of SEN alloys are as follows.(1)A dense multi-oxide layer of SEN alloys comprising MgO,CaO,and Y_(2)O_(3) impedes the outward dispersion of Mg vapor and the inward penetration of O_(2) during oxidation,thereby enhancing the oxidation and ignition resistances.(2)The presence of Ca-and Y-based second-phase particles in SEN alloys can enhance their corrosion resistance because Ca-containing particles prevent the spread of corrosion,and the replacement of Al-containing particles with less noble ones containing Y(e.g.,Al–Mn–Y or Al–Y particles)retards corrosion.(3)The addition of minor amounts of Ca and Y renders excellent mechanical properties due to improved strengthening *** enhanced properties are attributed to more pronounced dynamic recrystallization and grain refining behaviors caused by the second-phase particles during extrusion.(4)Despite the presence of various types of second-phase particles,the fatigue properties of SEN9 alloys are similar to those of commercial AZ91 alloys.(5)Simultaneous introduction of Ca and Y suppresses the formation of Mg17Al12 discontinuous precipitates during aging,leading to the enhanced elongation of aged SEN alloys.(6)Adding mischmetal into the SEN9 alloy leads to a six-fold enhancement in ***,the studies conducted on SEN alloys demonstrate their excellent ignition and corrosion resistances and mechanical properties,which broaden the industrial applications of Mg alloys by addressing their inherent weaknesses.

关键词： SEN magnesium alloy Corrosion resistance Ignition resistance Mechanical properties Extrudability.

Practical operating flexibility of a bifunctional freestanding membrane for efficient anion exchange membrane water electrolysis across all current ranges

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Carbon Energy 2024年第9期6卷 306-324页

作者： Hong-jin Son Jeemin Hwang Min Young Choi Seung Hee park Jae Hyuk Jang Byungchan Han sung Hoon Ahn Department of Bio-Chemical Engineering Chosun UniversityGwangjuRepublic of Korea Fuel Cell Research and Demonstration Center Hydrogen Energy Research DivisionKorea Institute of Energy Research(KIER)Buan-gunJeollabuk-doRepublic of Korea Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoulRepublic of Korea Center for Research Equipment Korea Basic Science InstituteDaejeonRepublic of Korea

This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic ***,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is *** method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss *** evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis *** technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current *** symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient *** results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology.

关键词： AEM water electrolysis fibrous membrane iR correction free operational stability symmetric configuration

Highly Aligned Ternary Nanofiber Matrices Loaded with MXene Expedite Regeneration of Volumetric Muscle Loss

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Nano-Micro Letters 2024年第4期16卷 269-292页

作者： Moon sung Kang Yeuni Yu Rowoon park Hye jin Heo Seok Hyun Lee Suck Won Hong Yun Hak Kim Dong‑Wook Han Department of Cogno‑Mechatronics Engineering College of Nanoscience and NanotechnologyPusan National UniversityBusan 46241Republic of Korea Medical Research Institute School of MedicinePusan National UniversityYangsan 50612Republic of Korea Department of Anatomy School of MedicinePusan National UniversityYangsan 50612Republic of Korea Engineering Research Center for Color‑Modulated Extra‑Sensory Perception Technology Pusan National UniversityBusan 46241Republic of Korea Department of Biomedical Informatics School of MedicinePusan National UniversityYangsan 50612Republic of Korea Periodontal Disease Signaling Network Research Center and Dental and Life Science Institute School of DentistryPusan National UniversityYangsan 50612Republic of Korea BIO‑IT Fusion Technology Research Institute Pusan National UniversityBusan 46241Republic of Korea Present Address:Osstem Implant Inc. Seoul 07789Republic of Korea

Current therapeutic approaches for volumetric muscle loss(VML)face challenges due to limited graft availability and insufficient *** overcome these limitations,tissue-engineered scaffolds have emerged as a promising *** this study,we developed aligned ternary nanofibrous matrices comprised of poly(lactide-co-ε-caprolactone)integrated with collagen and Ti_(3)C_(2)T_(x)MXene nanoparticles(NPs)(PCM matrices),and explored their myogenic potential for skeletal muscle tissue *** PCM matrices demonstrated favorable physicochemical properties,including structural uniformity,alignment,microporosity,and *** vitro assays revealed that the PCM matrices promoted cellular behaviors and myogenic differentiation of C2C12 ***,in vivo experiments demonstrated enhanced muscle remodeling and recovery in mice treated with PCM matrices following VML *** insights from next-generation sequencing revealed that MXene NPs facilitated protein and ion availability within PCM matrices,leading to elevated intracellular Ca^(2+)levels in myoblasts through the activation of inducible nitric oxide synthase(i NOS)and serum/glucocorticoid regulated kinase 1(SGK1),ultimately promoting myogenic differentiation via the m TOR-AKT ***,upregulated i NOS and increased NO–contributed to myoblast proliferation and fiber fusion,thereby facilitating overall myoblast *** findings underscore the potential of MXene NPs loaded within highly aligned matrices as therapeutic agents to promote skeletal muscle tissue recovery.

关键词： Ti_(3)C_(2)T_(x)MXene nanoparticle Ternary nanofibrous matrices Myogenesis Regeneration of volumetric muscle loss Next generation sequencing

Hard-to-Soft Transition in Radial Buckling of Multi-Concentric Nanocylinders

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World Journal of Mechanics 2012年第1期2卷 42-50页

作者： sung-jin park Motohiro Sato Tetsuro Ikeda Hiroyuki Shima Department of Urban and Environment Engineering University of Incheon Incheon Korea Division of Applied Physics Faculty of Engineering Hokkaido University Sapporo Japan Division of Engineering and Policy for Sustainable Environment Faculty of Engineering Hokkaido University Sapporo Japan Division of Engineering and Policy for Sustainable Environment Graduate School of Engineering Hokkaido University Sapporo Japan

We investigate the cross-sectional buckling of multi-concentric tubular nanomaterials, which are called multiwalled carbon nanotubes (MWNTs), using an analysis based on thin-shell theory. MWNTs under hydrostatic pressure experience radial buckling. As a result of this, different buckling modes are obtained depending on the inter-tube separation d as well as the number of constituent tubes N and the innermost tube diameter. All of the buckling modes are classified into two deformation phases. In the first phase, which corresponds to an elliptic deformation, the radial stiffness increases rapidly with increasing N. In contrast, the second phase yields wavy, corrugated structures along the circumference for which the radial stiffness declines with increasing N. The hard-to-soft phase transition in radial buckling is a direct consequence of the core-shell structure of MWNTs. Special attention is devoted to how the variation in d affects the critical tube number Nc, which separates the two deformation phases observed in N -walled nanotubes, i.e., the elliptic phase for N Nc. We demonstrate that a larger d tends to result in a smaller Nc, which is attributed to the primary role of the interatomic forces between concentric tubes in the hard-to-soft transition during the radial buckling of MWNTs.

关键词： Carbon Nanotube Buckling Radial Corrugation High Pressure Phenomenon Van der Waals Coupling Multiple Core-Shell Structure Thin Shell Theory

Random pinhole attenuator for high-power laser beams

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High Power Laser Science and Engineering 2024年第3期12卷 116-121页

作者： Seong Cheol park Hyeok Yun jin Woo Yoon Seong Ku Lee Jae Hee sung Il Woo Choi Chang Hee Nam Kyung Taec Kim Department of Physics and Photon Science Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea Center for Relativistic Laser Science Institute for Basic ScienceGwangjuRepublic of Korea Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea

The intensity attenuation of a high-power laser is a frequent task in the measurements of optical *** intensity can be attenuated by inserting an optical element,such as a partial reflector,polarizer or absorption *** devices are,however,not always easily applicable,especially in the case of ultra-high-power lasers,because they can alter the characteristics of a laser beam or become easily *** this study,we demonstrated that the intensity of a laser beam could be effectively attenuated using a random pinhole attenuator(RPA),a device with randomly distributed pinholes,without changing the beam *** this device,a multi-PW laser beam was successfully attenuated and the focused beam profile was measured without any alterations of its *** addition,it was confirmed that the temporal profile of a laser pulse,including the spectral phase,was ***,the RPA possesses significant potential for a wide range of applications.

关键词： high-power laser intensity attenuation laser diagnostics

Acetylacetone-TiO_(2) Promoted Large Area Compatible Cascade Electron Transport Bilayer for Efficient Perovskite Solar Cells

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Energy & Environmental Materials 2024年第2期7卷 221-228页

作者： Hyong Joon Lee jin Kyoung park jin Hyuck Heo Sang Hyuk Im Department of Chemical and Biological Engineering Korea University145 Anam-ro Seongbuk-guSeoul 17104Korea

In designing efficient perovskite solar cells(PSCs),the selection of suitable electron transport layers(ETLs)is critical to the final device performance as they determine the driving force for selective charge ***_(2)nanoparticles(NPs)based ETLs have been a popular choice for PSCs due to superior electron mobility,but their relatively deep-lying conduction band energy levels(ECB)result in substantial potential ***,TiO_(2)NPs establish favorable band alignment owing to shallower ECB,but their low intrinsic mobility and abundant surface trap sites impede the final *** this reason,constructing a cascaded bilayer ETL is highly desirable for efficient PSCs,as it can rearrange energy levels and exploit on advantages of an individual *** this study,we prepare SnO_(2)NPs and acetylacetone-modified TiO_(2)(Acac-TiO_(2))NPs and implement them as bilayer SnO_(2)/Acac-TiO_(2)(BST)ETL,to assemble cascaded energy band ***_(2)contributes to rapid charge carrier transport from high electron mobility while Acac-TiO_(2)minimizes band-offset and effectively suppresses interfacial ***,the optimized BST ETL generates synergistic influence and delivers power conversion efficiency(PCE)as high as 23.14%with open-circuit voltage(V_(oc))reaching 1.14 ***,the BST ETL is transferred to a large scale and the corresponding mini module demonstrates peak performance of 18.39%PCE from 25 cm^(2)aperture ***,the BST-based mini module exhibit excellent stability,maintaining 83.1%of its initial efficiency after 1000 h under simultaneous 1 Sun light-soaking and damp heat(85℃/RH 85%)environment.

关键词： acetylacetone large area perovskite solar cells TiO_(2)

Electrochemically Deposited CZTSSe Thin Films for Monolithic Perovskite Tandem Solar Cells with Efficiencies Over 17%

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Energy & Environmental Materials 2024年第1期7卷 147-152页

作者： Sun Kyung Hwang Ik Jae park Se Won Seo Jae Hyun park So Jeong park jin Young Kim Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Korea Department of Applied Physics Sookmyung Women's UniversitySeoul 04310Korea Research Institute of Advanced Materials and Systems Sookmyung Women's UniversitySeoul 04310Korea Research Institute of Advanced Materials(RIAM) Seoul National UniversitySeoul 08826Korea

In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom ***,we firstly demonstrate an efficient monolithic two-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom *** surface roughness(R_(rms))of the CZTSSe thin film could be reduced from 424 to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode,which can be further reduced to 22 nm after the subsequent ion-milling *** perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell,resulting in the efficient perovskite/CZTSSe tandem solar *** the current matching between two subcells involving the thickness control of the perovskite layer,the best performing tandem device exhibited a high conversion efficiency of 17.5%without the hysteresis effect.

关键词： CZTSSe monolithic tandem solar cells perovskite solution process surface roughness control

Real-Time Tunable Gas Sensing Platform Based on SnO_(2) Nanoparticles Activated by Blue Micro-Light-Emitting Diodes

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Nano-Micro Letters 2024年第12期16卷 103-119页

作者： Gi Baek Nam Jung-El Ryu Tae Hoon Eom Seung Ju Kim Jun Min Suh Seungmin Lee sungkyun Choi Cheon Woo Moon Seon Ju park Soo Min Lee Byungsoo Kim sung Hyuk park jin Wook Yang Sangjin Min Sohyeon park sung Hwan Cho Hyuk jin Kim Sang Eon Jun Tae Hyung Lee Yeong Jae Kim Jae Young Kim Young Joon Hong Jong-In Shim Hyung-Gi Byun Yongjo park Inkyu park Sang-Wan Ryu Ho Won Jang Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Research Laboratory of Electronics Department of Mechanical EngineeringMassachusetts Institute of TechnologyCambridgeMA 02139USA Ming Hsieh Department of Electrical and Computer Engineering University of Southern CaliforniaLos AngelesCA 90089USA Department of Display Materials Engineering Soonchunhyang UniversityAsan 31538Republic of Korea Department of Photonics and Nanoelectronics BK21 FOUR ERICA-ACE CenterHanyang University ERICAAnsan 15588Republic of Korea Department of Nanotechnology and Advanced Materials Engineering Sejong UniversitySeoul 05006Republic of Korea Department of Electronics Information and Communication EngineeringKangwon National UniversitySamcheok 25913Republic of Korea Advance Institute of Convergence Technology Seoul National UniversitySuwon 16229Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Department of Physics Chonnam National UniversityGwangju 500-757Republic of Korea

Micro-light-emitting diodes(μLEDs)have gained significant interest as an activation source for gas sensors owing to their advantages,including room temperature operation and low power ***,despite these benefits,challenges still exist such as a limited range of detectable gases and slow *** this study,we present a blueμLED-integrated light-activated gas sensor array based on SnO_(2)nanoparticles(NPs)that exhibit excellent sensitivity,tunable selectivity,and rapid detection with micro-watt level power *** optimal power forμLED is observed at the highest gas response,supported by finite-difference time-domain ***,we first report the visible light-activated selective detection of reducing gases using noble metal-decorated SnO_(2)*** noble metals induce catalytic interaction with reducing gases,clearly distinguishing NH3,H2,and ***-time gas monitoring based on a fully hardwareimplemented light-activated sensing array was demonstrated,opening up new avenues for advancements in light-activated electronic nose technologies.

关键词： Micro-LED Gas sensor array Low power consumption Metal decoration Real-time detection