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Journal of Energy Chemistry 2021年第1期30卷 326-331,I0011页

作者： Jiyeon lee jong Gyeong Kim Chanho Pak Graduate Program of Energy Technology School of Integrated TechnologyInstitute of Integrated TechnologyGwangju Institute of Science and TechnologyGwangju 61005Republic of Korea

Fuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and *** fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and ***,their final product is only water,instead of pollutants like carboFuel cells are one of the most competitive alternative energy sources because their theoretical efficiency is~15%higher than that of internal combustion engines (ICEs) and they are considered cleaner and *** fuel cells are used to replace ICEs in cars and energy conversion systems,the system efficiency increases;furthermore,the process becomes more environmentally-friendly because fuel cells produce electricity by using only hydrogen and oxygen,obtained by purifying atmospheric air by filtering out dust and ***,their final product is only water,instead of pollutants like carbon dioxide.n dioxide.

关键词： Non-precious-metal catalyst Oxygen reduction reaction Size effect Electrolyte accessibility Alkaline fuel cell

Microstructural evolution of pre-twinned Mg alloy with annealing temperature and underlying boundary migration mechanism

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Journal of Magnesium and Alloys 2023年第8期11卷 2953-2966页

作者： Ye Jin Kim jong Un lee Gyo Myeong lee Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea

This study investigates the variations in the microstructural characteristics of a pre-twinned Mg alloy with the temperature of the subsequent annealing *** this end,a rolled AZ31 alloy is compressed to 3%plastic strain along the rolling direction(RD)to activate{10-12}twinning and is subsequently annealed at 200,250,300,350,and 400℃.Numerous{10-12}twins are formed throughout the compressed material,leading to the formation of a RD-oriented *** an annealing temperature of 200℃,no microstructural variations occur during *** the annealing temperature increases from 250 to 400℃,the residual strain energy and remaining twin boundaries of the annealed material decrease owing to the promoted static recovery and the increased area fraction of twin-free grown ***,an increase in the annealing temperature results in a gradual microstructural transition from a fully twinned grain structure to a completely twin-free grain *** microstructural evolution during annealing is predominantly governed by the movement of high-angle grain boundaries via a strain-induced boundary migration mechanism,and a few twin boundaries migrate above 350℃because of their lower boundary *** boundary migration behavior and resultant microstructural evolution are discussed in detail based on the variations in boundary mobility and driving force for boundary migration with annealing temperature.

关键词： Rolled Mg alloy {10-12}twin Grain growth Boundary migration Annealing

Interfacial Behaviors of Basalt Fiber‑Reinforced Polymeric Composites: A Short Review

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Advanced Fiber Materials 2022年第6期4卷 1414-1433页

作者： Seong‑Hwang Kim jong‑Hoon lee jong‑Woo Kim Seul‑Yi lee Soo‑Jin Park Department of Chemistry Inha University100 InharoIncheon 22212South Korea

Basalt fibers(BFs)have emerged as a promising thermal insulation material for various applications,such as fireproof clothes/walls and protective equipment in military and civil *** have many desirable characteristics,such as low thermal conductivity,excellent flame resistance,exceptional mechanical strength,facile manipulability,environmental friendliness,and ***,the low intrinsic interfacial properties of BFs due to their chemical inertness and macro-scaled sizes have been a challenge for high performance of BFs-reinforced polymeric composites(BFRPs).Since the mechanical properties of BFRPs significantly depend on the interfacial interaction between the fibers and the matrix,it is critical to understand how incorporating BFs influences the properties of the *** this end,the aim of this review is to report on recent research progress with emphasis on the interfacial behavior in *** relationships between the fiber–matrix interfacial adhesion and the mechanical properties of the BFRPs are briefly described with systematic and up-to-date surface modification techniques summarized into two categories:surface modifications(“wet”and“dry”)and multi-scaled ***,several strategies for increasing the interfacial adhesion of BFs within the polymeric matrix to provide new ideas and insight for future research on the BFRPs are discussed.

关键词： Basalt fibers Polymeric matrix Surface modification Interface

Novel Architecture of OneM2M-Based Convergence Platform for Mixed Reality and IoT

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Computers, Materials & Continua 2022年第4期71卷 51-69页

作者： Seungwoon lee Woogeun kil Byeong-hee Roh SJ Kim Jin-suk Kang Department of Computer Engineering and Department of AI Convergence Network Ajou UniversitySuwon16499Korea Howard R.Hughes College of Engineering University of NevadaLas VegasNV89154USA AST Co.Ltd. Suwon16681Korea

There have been numerous works proposed to merge augmented reality/mixed reality(AR/MR)and Internet of Things(IoT)in various ***,they have focused on their specific target applications and have limitations on interoperability or reusability when utilizing them to different domains or adding other devices to the *** paper proposes a novel architecture of a convergence platform for AR/MR and IoT systems and *** proposed architecture adopts the oneM2M IoT standard as the basic framework that converges AR/MR and IoT systems and enables the development of application services used in general-purpose environments without being subordinate to specific systems,domains,and device *** implement the proposed architecture utilizing the open-source oneM2M-based IoT server and device platforms released by the open alliance for IoT standards(OCEAN)and Microsoft HoloLens as an MR device *** also suggest and demonstrate the practical use cases and discuss the advantages of the proposed architecture.

关键词： Internet of things(IoT) augmented realty(AR) mixed reality(MR) microsoft HoloLens oneM2M convergence platform

Relationship between intraocular pressure and parameters of obesity in ocular hypertension

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International Journal of Ophthalmology(English edition) 2020年第5期13卷 794-800页

作者： Min Won Ahn Ji Woong lee jong Hoon Shin jong Soo lee Busan Sungmo Eye Hospital Busan 48064Korea Department of Ophthalmology Pusan National University College of Medicine and Medical Research Institute of Pusan National University HospitalBusan 49241Korea Department of Ophthalmology Pusan National University Yangsan HospitalYangsan 50612Korea

AIM:To evaluate the correlation between intraocular pressure(IOP)and various obesity-related health factors in patients with ocular hypertension in ***:A total of 40850 subjects underwent age,sex,body weight,and height assessments and automated multiphasic tests,including non-contact tonometry,automated perimetry,fundus photography,systolic/diastolic blood pressure measurement,and evaluation of obesity-related health parameters such as obesity index,body mass index(BMI),a body shape index(ABSI),and waist-to-height ratio(WtHR).Subjects were divided into ocular hypertension group and normal IOP group according to IOP after matching of age and ***:Of 40850 participants,1515(3.7%)had ocular hypertension,and 1515 with normal IOP were selected as controls using propensity score *** mean IOP of control group was 15.3±2.3 mm Hg,compared with 23.3±1.6 mm Hg in ocular hypertension ***,obesity index,BMI,and WtHR in the ocular hypertension group were significantly higher than in the normal IOP group(P<0.001,P<0.001,P=0.009,P=0.002).IOP of ocular hypertension was positively correlated with obesity index(P=0.027)and BMI(P=0.016),whereas IOP of control was positively correlated with blood pressure(P<0.001,P=0.002),obesity index(P<0.001),BMI(P<0.001),and WHtR(P=0.002).Systolic blood pressure(β=0.022,P<0.001)and body weight(β=0.016,P=0.02)were precursors of IOP in normal subjects,but sex(male;β=-0.231,P=0.008)and obesity index(β=-0.007,P=0.017)were precursors of ocular hypertension according to multiple regression ***:Among various obesity-related health parameters,obesity index is the best indicator for further increase in IOP in ocular hypertension group.

关键词： intraocular pressure ocular hypertension body mass index body shape index waist-to-height ratio

Design,Fabrication,and Analysis of Flapping and Folding Wing Mechanism for a Robotic Bird

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Journal of Bionic Engineering 2020年第2期17卷 229-240页

作者： Seung Wan Ryu jong Gu lee Hyoun Jin Kim Department of Mechanical&Aerospace Engineering and Automation Systems Research Institute Seoul National UniversitySeoul 08826Republic of Korea

Emulating periodic main wing movement of a bird for generating lift and thrust remains a significant challenge in developing a robotic *** sequences of main wing motion are comprised of flapping,folding,bending,and *** this paper,we concentrate on the flapping and folding motion,and design two wing mechanisms based on a 4-bar linkage structure:one is only for Flapping Motion(FM)and the other is for simultaneous Flapping and Folding Motion(FFM)during a wing *** derive relationships between length and angle of links to analyze kinematic characteristics of the mechanisms and conduct an optimization to select the length parameters of links that allow maximization of the flapping *** run a simulation to confirm the performance of the optimized parameters by examining physical properties,and fabricate two wing mechanisms *** particular,the folding motion is achieved without using an additional *** measurements to investigate a lift profile of each mechanism and their quantitative comparison of the performance of both types confirm the benefits of the folding motion in the perspectives of wing frequency and *** expect that our kinematic formulation,design procedures,and comparative measurement results can help develop a wing mechanism to create a truly biomimetic robotic bird.

关键词： biomimetic robotic bird flapping and folding wing mechanism wing kinematics force measurement

Surface-roughened current collectors for anode-free all-solid-state batteries

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Journal of Energy Chemistry 2022年第7期31卷 248-257,I0007页

作者： Donghee Gu Hyoungchul Kim jong-Ho lee Sangbaek Park Energy Materials Research Center Korea Institute of Science and Technology(KIST)Seoul 02792.Republic of Korea School of Civil Environmental and Architectural EngineeringKorea University.Seoul 02841.Republic of Korea Division of Nanoscience and Technology University of Science and Technology(UST)Seoul02792.Republicof Korea Department of Materials Science and Engineering Chungnam National UniversityDaejeon 34134.Republic of Korea

Anode-free all-solid-state batteries(AFASSBs), composed of a fully lithiated cathode and a bare current collector(CC) that eliminates excess lithium, can maximize the energy density(because of a compact cell configuration) and improve the safety of solid-state systems. Although significant progress has been made by modifying CCs in liquid-based anode-free batteries, the role of CCs and the mechanism of Li formation on CCs in AFASSBs are still unexplored. Here, we systematically investigate the effect of the surface roughness of the CCs on the Li plating/stripping behavior in AFASSBs. The results show that the moderately roughened CC substantially improves the Coulombic efficiency and cycle stability of AFASSBs owing to the increased contact points between the solid electrolyte and the roughened CC. In contrast, the excessively roughened CC deteriorates the performance owing to the contact ***, an ex situ interface analysis reveals that the roughened surface of the CC could suppress the interfacial degradation during the Li ion extraction from a sulfide solid electrolyte to a CC. This provides an indication to the origin that hinders the electrochemical performance of AFASSBs. These findings show the potential for the application of surface-engineered CCs in AFASSBs and provide guidelines for designing advanced CCs.

关键词： Anode-free Solid-state batteries Current collectors Surface roughness Li formation

In situ thickness control of black phosphorus field-effect transistors via ozone treatment

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Nano Research 2016年第10期9卷 3056-3065页

作者： Suhyun Kim Younghun Jung jong-Young lee Gwan-Hyoung lee Jihyun Kim Department of Chemical and Biological Engineering Korea University Seou102841 Republic of Korea Department of Materials Science and Engineering Yonsei University Seou103722 Republic of Korea

A simple and reproducible method to control the thickness of black phosphorus flakes in real time using a UV/ozone treatment is demonstrated. Back-gated black phosphorus field-effect transistors （FETs） were fabricated using thick black phosphorus flakes obtained by thinning of black phosphorus, as oxygen radicals generated by UV irradiation formed phosphorus oxides on the surface. In order to monitor the thickness effect on the electrical properties, the fabricated FETs were loaded in the UV/ozone chamber, where both the optical （micro-Raman spectroscopy and optical microscopy） and electrical properties （current-voltage characteristics） were monitored in situ. We observed an intensity decrease of the Raman modes of black phosphorus while the field-effect mobility and on/off ratio increased by 48% and 6,800%, respectively. The instability in ambient air limits the investigation and implementation of ultra-thin black phosphorus. However, the method reported in this study allowed us to start with thick black phosphorous flakes, providing a reliable approach for optimizing the electrical performance of black phosphorus-based electronic devices. We believe that these results can motivate further studies using mono- and few-layer black phosphorus.

关键词： black phosphorus in situ thinning UV/ozone treatment

Preparation of SnO Nanosheets and SnO_2 Fine Powders by Hydrazine Method

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稀有金属材料与工程 2006年第A3期35卷 43-46页

作者： Kang-Min Kim jong-Heun lee Department of Materials Science & Engineering Korea UniversitySeoul 136-713Korea

SnO nanosheets and SnO_2 nanopowder were prepared by hydrazine (N_2H_4)-based chemical routes and their gas sensing characteristics were investigated.A SnCl_2-Hydrazine complex (Sn[ N_2H_4)_x]·yH_2O) was formed by a reaction between a SnCl_2 aqueous solution and N_2H_4·H_*** this complex was heat-treated at 450℃,SnO_2 nanopowders were prepared by the decomposition of the *** sensor fabricated from the SnO_2 nano powders showed a good recovery,fast response and high sensitivity for CO 50μg/g (R_a/R_g=1.87),C_2H_5OH 100μg/g (R_a/R_g=4.80),and acetone 100μg/g (R_a/R_g=1.50).SnO nano- sheets could be prepared when a NaOH solution was added to the solution containing the ***_2 nano sheets prepared by the oxidation of SnO nanosheets at 700℃in air atmosphere also showed a good sensitivity R_a/R_g=1.79) for CO 50μg/g at 400℃.The hydrazine method provided an effective tool to controlling the morphology and oxidation state of the tin oxide powders.

关键词： SnO2 SnO hydrazine method gas sensor nanosheets nanopowders

Are prostatic calculi independent predictive factors of lower urinary tract symptoms？

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Asian Journal of Andrology 2010年第2期12卷 221-226页

作者： Sung-Woo Park jong-kil Nam Sang-Don lee Moon-Kee Chung Medical Research Institute and Department of Urology Pusan National University Yangsan Hospital Yangsan 626-770Korea

We determined the correlation between prostatic calculi and lower urinary tract symptoms （LUTS）,as well as the predisposing factors of prostatic calculi. Of the 1 527 patients who presented at our clinic for LUTS,802underwent complete evaluations,including transrectal ultrasonography,voided bladder-3 specimen and international prostatic symptoms score （IPSS）. A total of 335 patients with prostatic calculi and 467 patients without prostatic calculi were divided into calculi and no calculi groups,respectively. Predictive factors of severe LUTS and prostatic calculi were determined using uni/multivariate analysis. The overall IPSS score was 15.7±9.2 and 14.1±9.1 in the calculi and no calculi group,respectively （P = 0.013）. The maximum flow rate was 12.1±6.9 and 14.2±8.2 mL s^（-1） in the calculi and no calculi group,respectively （P = 0.003）. On univariate analysis for predicting factors of severe LUTS,differences on age （P = 0.042）,prostatic calculi （P = 0.048） and prostatitis （P = 0.018） were statistically significant. However,on multivariate analysis,no factor was significant. On multivariate analysis for predisposing factors of prostatic calculi,differences on age （P〈0.001） and prostate volume （P = 0.001） were significant. To our knowledge,patients who have prostatic calculi complain of more severe LUTS. However,prostatic calculi are not an independent predictive factor of severe LUTS. Therefore,men with prostatic calculi have more severe LUTS not only because of prostatic calculi but also because of age and other factors. In addition,old age and large prostate volume are independent predisposing factors for prostatic calculi.

关键词： micturition prostate prostatic diseases