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Tribological behavior of TiN,AlTiN,and AlTiCrN coatings in atmospheric and vacuum environments

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Friction 2024年第11期12卷 2611-2626页

作者： Youn-Hoo HWANG Kuk-Jin seo Tae-Hyeong kiM You Jin min Yuzhen LIU Dae-Eun kiM Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Mechatronics and Energy Engineering Ningbo Tech UniversityNingbo 315211China

In this study,the tribological characteristics of TiN,AlTiN,and AlTiCrN coatings sliding against a SUS420J1 stainless steel pin were investigated in atmospheric and vacuum *** coatings were deposited on SUS440C substrates using the arc-physical vapor deposition *** friction and wear behavior of the coatings were evaluated based on the systematic analyses of the friction coefficient data as well as the physical and chemical state of the wear *** results revealed that the friction coefficients of the SUS440C specimen and AlTiCrN coatings increased,whereas those of the TiN and AlTiN coatings decreased when the environment was changed from atmospheric to *** was confirmed that the formation of an oxide layer and adsorption of oxides on the surface were dominant factors that influenced the tribological behavior in the atmospheric *** the other hand,the compatibility,oxidation inhibition,and droplets of the surface mainly affected the frictional characteristics in the vacuum *** results of this work are expected to aid in the selection of proper coating materials for tribological systems operating in a vacuum.

关键词： friction wear coating vacuum TiN

A Solvent-Free Covalent Organic Framework Single-Ion Conductor Based on Ion-Dipole Interaction for All-Solid-State Lithium Organic Batteries

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Nano-Micro Letters 2024年第12期16卷 189-200页

作者： Zhongping Li Kyeong-seok Oh Jeong-min seo Wenliang Qin Soohyoung Lee Lipeng Zhai Changqing Li Jong-Beom Baek Sang-Young Lee Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-RoSeodaemun-GuSeoul 03722Republic of Korea School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)50 UNIST-GilEonyang-EupUlju-GunUlsan 44919Republic of Korea Henan Key Laboratory of Functional Salt Materials Center for Advanced Materials ResearchZhongyuan University of TechnologyZhengzhou 450007People’s Republic of China Department of Battery Conflation Engineering Yonsei University50Yonsei-RoSeodaemun-GuSeoul 03772Republic of Korea Department of Battery Engineering Yonsei University50Yonsei-RoSeodaemun-GuSeoul 03772Republic of Korea

Single-ion conductors based on covalent organic frameworks(COFs)have garnered attention as a potential alternative to currently prevalent inorganic ion conductors owing to their structural uniqueness and chemical ***,the sluggish Li+conduction has hindered their practical ***,we present a class of solvent-free COF single-ion conductors(Li-COF@P)based on weak ion-dipole interaction as opposed to traditional strong ion-ion *** ion(Li+from the COF)-dipole(oxygen from poly(ethylene glycol)diacrylate embedded in the COF pores)interaction in the Li-COF@P promotes ion dissociation and Li+migration via directional ionic *** by this single-ion transport behavior,the Li-COF@P enables reversible Li plating/stripping on Li-metal electrodes and stable cycling performance(88.3%after 2000 cycles)in organic batteries(Li metal anode||5,5’-dimethyl-2,2’-bis-p-benzoquinone(Me2BBQ)cathode)under ambient operating conditions,highlighting the electrochemical viability of the Li-COF@P for all-solid-state organic batteries.

关键词： Solid organic single-ion conductors Solvent-free covalent organic frameworks All-solid-state Li organic batteries Ion-dipole interaction Pore functionalization

Comparative efficacy and optimal duration of first-line antibiotic regimens for acute otitis media in children and adolescents:a systematic review and network meta-analysis of 89 randomized clinicaltrials

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World Journal of Pediatrics 2024年第3期20卷 219-229页

作者： min seo kim Jae Han kim seohyun Ryu Seung Won Lee Dong Keon Yon Eunyoung kim Ai Koyanagi Elena Dragioti Jae Il Shin Lee Smith Samsung Advanced Institute forHealth Sciences&Technology(SAIHST) Samsung Medical CenterSungkyunkwan UniversitySeoulRepublic of Korea Yonsei University Collegeof Medicine SeoulRepublicof Korea Department of Precision Medicine Sungkyunkwan University School of MedicineSuwonRepublic of Korea Center for Digital Health Medical Science Research InstituteKyung Hee University College of MedicineSeoulRepublic of Korea Evidence-Based Research Laboratory Department of Clinical Pharmacy and Pharmaceutical CareCollege of PharmacyChung-Ang UniversitySeoulRepublic of Korea Parc Sanitari Sant Joan de Deu/CIBERSAM/ISCIII Universitat de BarcelonaFundacio Sant Joan de Déu.Sant Boi de LlobregatBarcelonaSpain ICREA Pg.Lluis Companys 23BarcelonaSpain Pain and Rehabilitation Centre and Department of Medical and Health SciencesLinkoping University58185 LinkopingSweden Department of Pediatrics Yonsei University College of MedicineYonsei-ro 50Seodaemun-gu8044Seoul 03722Republic of Korea Centre for Health Performanceand WellbeingAnglia Ruskin UniversityCambridge CB11PTUK Research Laboratory Psychology of Patients Families&Health ProfessionalsDepartment of NursingSchool of Health SciencesUniversity of IoanninaIoannina 45500Greece

Introduction Antibiotic use for acute otitis media(AOM)is one of the major sources of antimicrobial ***,the effective minimal antibiotic duration for AOM remains ***,guidelines often recommend broad ranges(5-10 days)of antibiotic use,yet the clinical impact of such a wide window has not been *** We systematically searched PubMed/MEDLINE,Embase,Scopus,Web of Science,and Cochrane Library from database inception to 6 October *** meta-analysis was conducted on randomized controlled trials that assessed antibiotic treatment for AOM in children(PROSPERO CRD42020196107).Results For amoxicillin and amoxicillin-clavulanate,7-day regimens were noninferior to 10-day regimens in clinical responses[amoxicillin:risk ratio(RR)0.919(95%CI 0.820-1.031),amoxicillin-clavulanate:RR 1.108(0.957-1.282)],except for≤2 *** the third-generation cephalosporins,7-day and 10-day regimens had similar clinical responses compared to placebo[7-day:RR 1.420(1.190-1.694),10-day:RR 1.238(1.125-1.362)compared to placebo].However,5-day regimens of amoxicillin-clavulanate and third-generation cephalosporins were inferior to 10-day *** to amoxicillin,a shorter treatment duration was tolerable with *** Our findings indicated that 1O days of antibiotic use may be unnecessarily long,while the treatment duration should be longer than 5 ***,5-day regimens would be sufficient for a modest treatment *** findings revealed that the current wide range of recommended antibiotic durations may have influenced the clinical outcome of AOM,and a narrower antibiotic duration window should be re-established.

关键词： Amoxicillin-potassium Amoxicillin Antibacterial agents Cephalosporins Duration of therapy

Realizing High Thermoelectric Performance in n-Type Se-Free Bi2Te3 Materials by Spontaneous Incorporation of FeTe2 Nanoinclusions

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Energy & Environmental Materials 2024年第4期7卷 344-354页

作者： Jamil Ur Rahman Woo Hyun Nam Yong-Jae Jung Jong Ho Won Jong-min Oh Nguyen Van Du Gul Rahman Víctor M.García-Suárez Ran He Kornelius Nielsch Jung Young Cho Won-seon seo Jong Wook Roh Sang-il kim Soonil Lee Kyu Hyoung Lee Hyun Sik kim Weon Ho Shin Leibniz Institute for Solid State and Materials Research Advanced Materials Convergence R&D Division Korea Institute of Ceramic Engineering & Technology Department of Electronic Materials Engineering Kwangwoon University Department of Energy Engineering Dankook University Faculty of Fundamental Science Phenikaa University Department of Physics Quaid-i-Azam University Departamento de Física Universidad de Oviedo Nanomaterials and Nanotechnology Research Center-CINN Department of Materials Science and Engineering Yonsei University School of Nano & Materials Science and Engineering Kyungpook National University Department of Materials Science and Engineering University of Seoul School of Materials Science and Engineering Changwon National University

Bi2Te3-based materials have drawn much attention from the thermoelectric community due to their excellent thermoelectric performance near room ***,the stability of existing n-type Bi2（Te,Se）3materials is still low due to the evaporation energy of Se (37.70 kJ mol-1) being much lower than that of Te (52.55 kJ mol-1).The evaporated Se from the material causes problems in interconnects of the module while degrading the efficiency.

关键词： Bi2Te3 energy harvesting FeTe2 nanoinclusion n-type materials thermoelectric

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting

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Frontiers in Energy 2024年第3期18卷 378-389页

作者： Zhao-ting SHANG Tang-ming LI Bing-qian HU min LIU Wang-ting LU Fan YU Yun ZHENG Key Laboratory of Optoelectronic Chemical Materials and Devices of ministry of Education College of Optoelectronic Materials and TechnologyJianghan UniversityWuhan 430056China Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China Department of Chemical Engineering University of WaterlooWaterlooOntario N2L 3G1Canada

The use of two-dimensional(2D)layered metal-organic frameworks(MOFs)as self-sacrificial templates has been proven to be a successful method to create high-efficiency Selenium(Se)-containing electrocatalysts for overall water ***,two strategies are then utilized to introduce Se element into the Co–Fe MOF,one being the etching of as-prepared MOF by seo_(2) solution,and the other,the replacing of SCN−with SeCN−as the construction *** electrochemical activity of the pristine 2D MOF and their calcinated derivatives for catalyzing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is evaluated and further *** is found that the effect of introducing Se on improving electrochemical catalytic activity is significant for the HER ***,the calcinated derivative in the replacing method exhibits an overpotential of 235 mV for HER and 270 mV for OER at a current density of 10 mA/*** comparing the two methods of introducing Se element into MOF,similar electrocatalytic activity can be achieved on the their calcinated *** high electrochemical performance of 2D CoFe-MOF derivatives may be resulted from the unique 2D hierarchical porous structure and strong synergistic effect between different components in the material.

关键词： 2D MOF selenium(Se)-containing materials hydrogen evolution reaction(HER) oxygen evolution reaction(OER)

Effect of internal sloshing on added resistance of ship

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Journal of Hydrodynamics 2017年第1期29卷 13-26页

作者： min-Guk seo Yonghwan kim Dong-min Park Korea Research Institute of Ships and Ocean Engineering DaejeonKorea Department of Naval Architecture and Ocean Engineering Seoul National UniversitySeoulKorea

The motion responses of ships carrying liquid cargo are affected not only by external wave excitation, but also by internal sloshing-induced forces and moments. Sloshing flow is coupled with the ship motion. This means the added resistance in waves may change when sloshing occurs inside the tank of the ship. In this study, the motion responses and added resistance of a ship, coupled with the sloshing-induced internal forces and moments are considered by using the linear potential theory. The three-dimensional Rankine panel method, in which the physical quantities are represented by using B-spline basis function, is applied. The sloshing flow of inner tanks is also simulated by Using the Rankine panel method and linearized boundary value problem. To study the added resistance, a near-field method, which integrates the second-order pressure on a body surface, is applied. The model ship is a blunt modified Wigley model with two inner tanks. Numerical results obtained without inner tanks are compared with the experimental data, and then the effect of filling ratio of inner tanks on ship motion and added resistance are observed. The components that induce added resistance are examined, and the effects of surge motion on sloshing flow and added resistance are briefly considered. This study shows that the sloshing flow inside the inner tanks may significantly influence not only the motion responses, but also added resistance, especially, when the incident wave frequency approaches the resonance frequency of the sloshing flow.

关键词： Added resistance sloshing seakeeping coupled effect Rankine panel method

Facile synthesis of fully ordered L10-FePt nanoparticles with controlled Pt-shell thicknesses for electrocatalysis

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Nano Research 2017年第8期10卷 2866-2880页

作者： Yonghoon Hong Hee Jin kim Daehee Yang Gaehang Lee ki min Nam Myung-Hwa Jung Young-min kim Sang-II Choi Won seok seo Department of Chemistry Sogang University Seou104107 Republic of Korea Department of Chemistry and Green-Nano Materials Research Center Kyungpook National University Daegu 41566 Repubfic of Korea Korea Basic Science Institute and University of Science and Technology Daejeon 34133 Republic of Korea Department of Chemistry Mokpo National University Jeonnam 58554 Republic of Korea Department of Physics Sogang University Seoul 04107 Republic of Korea Center for Integrated Nanostructure Physics Institute for Basic Science (IBS) Suwon 16419 Repubfic of Korea Department of Energy Science Sungkyunkwan University (SKKU) Suwon 16419 Republic of Korea

We report a simple one-step approach for the synthesis of -4 nm uniform and fully L10-ordered face-centered tetragonal （fct） FePt nanoparticles （NPs） embedded in -60 nm MCM-41 （fct-FePt NPs@MCM-41）. We controlled the Pt-shell thickness of the fct-FePt NPs by treating the fct-FePt NPs@MCM-41 with acetic acid （HOAc） or hydrochloric acid （HC1） under sonicafion, thereby etching the surface Fe atoms of the NPs. The fct-FePt NPs deposited onto the carbon support （fct-FePt NP/C） were prepared by mixing the fct-FePt NPs@MCM-41 with carbon and subsequently removing the MCM-41 using NaOH. We also developed a facile method to synthesize acid-treated fct-FePt NP/C by using a HF solution for simultaneous surface-Fe etching and MCM-41 removal. We studied the effects of both surface-Fe etching and Pt-shell thickness on the electrocatalytic properties of fct-FePt NPs for the methanol oxidation reaction （MOR）. Compared with the non-treated fct-FePt NP/C catalyst, the HOAc-treated and HCl-treated catalysts exhibit up to 34% larger electrochemically active surface areas （ECASAs）; in addition, the HCl-treated fct-FePt NP （with -1.0 nm Pt shell）/C catalyst exhibits the highest specific activity. The HF-treated fct-FePt NP/C exhibits an ECASA almost 2 times larger than those of the other acid-treated fct-FePt NP/C catalysts and shows the highest mass activity （1,435 mA·mgPt^-1, 2.3 times higher than that of the commercial Pt/C catalyst） and stability among the catalysts tested. Our findings demonstrate that the surface-Fe etching for the generation of the Pt shell on fct-FePt NPs and the Pt-shell thickness can be factors for optimizing the electrocatalysis of the MOR.

关键词： FePt face centered tetragonal bimetallic methanol oxidation reaction electrocatalysts

Engineered NiCo-LDH nanosheets- and ZnFe_(2)O_(4) nanocubes-decorated carbon nanofiber bonded mats for high-rate asymmetric supercapacitors

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Green Energy & Environment 2022年第6期7卷 1228-1240页

作者： Jae-Gyoung seong Tae Hoon Ko Danyun Lei Woong-ki Choi Yun-Su Kuk min-Kang seo Byoung-Suhk kim Department of Organic Materials&Fiber Engineering Jeonbuk National University567 Baekje-daeroDeokjin-guJeonju-siJeollabuk-do54896Republic of Korea Department of BIN Convergency Technology Jeonbuk National University567 Baekje-daeroDeokjin-guJeonju-siJeollabuk-do54896Republic of Korea Korea Institute of Carbon Convergence Technology Jeonju54852Republic of Korea Department of Environmental Biology and Water Engineering College of Urban ConstructionWuchang Shouyi UniversityWuhan430064China

In this work,we have prepared the hierarchically nanostructured core–shell NiCo layered double hydroxide(NiCo-LDH)nanosheets-and ZnFe_(2)O_(4) nanocubes-decorated polyacrylonitrile(PAN)/pitch-based carbon nanofibers(PPCNs)webs(NiCo-LDH@PPCNs as cathode and ZnFe_(2)O_(4)@PPCNs as anode materials)with the bonded network structure by a facile and scalable hydrothemal ***,the low-cost pitch with lower softening point(~90℃)as co-precursor was utilized to produce the PAN/pitch-based carbon nanofibers(PPCNs)with enhanced electrical *** obtained PPCNs with pitch content of 30%(PP30CNs)electrode material delivered higher specific capacitance(~67 F g^(-1))than that(~48 F g^(-1))of the PAN-based carbon nanofibers(PCNs)at 1 A g^(-1),due to the increased electrical conductivity and lower interfacial charge transfer resistance(RCT)of~0.16 ***,the NiCo-LDH-decorated PP30CNs(NiCoLDH@PP30CNs)as cathode material showed superior specific capacitance of 1162 F g^(-1) at 1.0 A g^(-1) and ultra-high retention rate of 91.56%at 10 A g^(-1).The ZnFe_(2)O_(4)@PP30CNs as anode material also showed higher specific capacitance of 282 F g^(-1) at 1 A g^(-1) and good rate capability with capacitance retention of 56.73%at 10 A g^(-1).The as-fabricated asymmetric NiCo-LDH@PP30CNs//ZnFe_(2)O_(4)@PP30CNs hybrid supercapacitor device delivered a specific capacitance of~98 F g^(-1) at 1 A g^(-1) and excellent capacitance retention of~88%after 5000 charge–discharge cycles.

关键词： Carbon nanofiber Pitch Asymmetric Rate capability Supercapacitor

Effect of friction on the contact stress of a coated polymer gear

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Friction 2020年第6期8卷 1169-1177页

作者： Su-min BAE Kuk-Jin seo Dae-Eun kiM Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea

Polymer gears are used extensively in various ***,durability issues have been emerging because of friction at gear tooth contact *** extend the lifetime of polymer gears,a low-frictional coating has been considered as a possible *** this study,a finite element simulation method was performed to investigate the contact stress between a pair of coated polymer *** simulation included various friction coefficients(COFs)for studying the effects of friction during the *** results revealed that the friction causes the contact stress to shift over the roll angle,which is attributed to the direction of the sliding friction based on a free-body *** also investigated the effects of coating and found that a thin coating has little effect on the bulk deformation behavior of the ***,the stress distribution in the coating at the pitch point was investigated as the COF *** zero friction,three notable stress regions were observed:1)the center of the surface,2)the end of the contact,and 3)the overall contact *** COF was increased in the micro-slip region of the contact interface,both tensile and compressive stresses in the coating *** study provides significant aid to engineers for understanding the stress response of the coating applied to polymer gears to achieve an optimal design.

关键词： coating contact stress finite element method(FEM) friction polymer gear