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Effect of Fe_2P in LiFePO_4/Fe_2P composite on electrochemical properties synthesized by MA and control of heat condition

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Rare Metals 2006年第z2期25卷 179-183页

作者： PARK jong Suk lee Kyung Tae lee Kyung Sub Department of Material Science and Engineering Hanyang University Seoul 133-731 Korea

In order to control the size and distribution of the high conductive Fe2P in LiFePO4/Fe2P composite, two different cooling rates (Fast: 15 ℃·min-1, Slow: 2 ℃·min-1) were employed after mechanical alloying. The discharge capacity of the fast cooled was 83 mAh·g-1 and the slow cooled 121 mAh·g-1. The particle size of the synthesized powder was examined by transmission electron microscopy and distribution of Fe2P was characterized using scanning electron microscopy (SEM). In addition, two-step heat treatment was carried out for better distribution of Fe2P. X-ray diffraction (XRD) and Rietveld refinement reveal that LiFePO4/Fe2P composite consists of 95.77% LiFePO4 and 4.33% of Fe2P.

关键词： LiFePO4/Fe2P composite mechanical alloying heat treatment discharge capacity

Response of phenology- and yield-related traits of maize to elevated temperature in a temperate region

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The Crop Journal 2017年第4期5卷 305-316页

作者： Dana Shim Kyu-jong lee Byun-Woo lee Department of Plant Science Seoul National University Seoul 151-921 Republic of Korea Research Institute for Agriculture and Life Sciences Seoul National University Seoul 151-921 Republic of Korea

Extreme high temperatures detrimental to maize production are projected to occur more frequently with future climate *** and yield-related traits were investigated under several levels of elevated temperature in two early-maturing hybrid cultivars:Junda 6(grown in northeastern China)and Chalok 1(grown in South Korea).They were cultivated in plastic houses in Suwon,Korea(37.27°N,126.99°E)held at target temperatures of ambient(AT),AT+1.5°C,AT+3°C,and AT+5°C at one sowing date in 2013 and three different sowing dates in *** and reproductive growth durations showed variation depending on sowing date,experimental year,and *** duration tended to decrease,but not necessarily,with temperature elevation,but somewhat increased again above a certain *** temperature-dependent variation was greater during grain filling than in the vegetative period before *** temperature showed no significant effects on duration or peak dates of silking and anthesis,and thus on anthesis–silking *** yield tended to decrease with temperature elevation above ambient,showing a sharper linear decrease with mean growing season temperature increase in Junda 6 than in Chalok *** decrease in kernel number accounted for a much greater contribution to the yield reductions due to temperature elevation than did the decrease in individual kernel weight in both *** harvestable kernel weight was not significantly affected by temperature elevation *** number showed a linear decrease with mean growth temperature from early ear formation to early grain-filling stage,with Junda 6 showing a much severer decrease than Chalok *** number reduction due to temperature elevation was attributable more to the decrease in differentiated ovule number than to the decrease in kernel set in Chalok 1,but largely to the decrease of kernel set in Junda 6.

关键词： Maize Elevated temperature Phenology Yield Yield-related traits

Preparation of TiAlN/ZrN and TiCrN/ZrN multilayers by RF magnetron sputtering

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中国有色金属学会会刊：英文版 2009年第4期19卷 795-799页

作者： jong-Kook lee G won-Seung YANG Department of Advanced Materials Engineering Chosun University BK21 Education Center of Mould Technology for Advanced Materials and Parts Chosun University

Titanium-based nitride coatings on cutting tools,press molds and dies can be used to prolong their life cycle because of their superior corrosion and oxidation ***/ZrN and TiCrN/ZrN multilayer coatings were prepared by RF magnetron sputtering,and their microstructural evolution and corrosion resistance during heat treatment were *** TiAlN/ZrN and TiCrN/ZrN multilayer coatings are degraded by heating up to 600 ℃ with the formation of oxides particles on the *** the heat treatment,the TiCrN/ZrN and TiAlN/ZrN multilayer coatings show the lowest corrosion current density and the highest polarization resistance at temperature range of 400-500 ℃.Consequently,the TiAlN/ZrN and TiCrN/ZrN multilayer coatings show good corrosion resistance at temperature range of 400-500 ℃ during heating.

关键词：射频磁控溅射溅射制备氮化锆多层膜钛铝耐腐蚀性腐蚀电流密度

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

The use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in South Korea

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Journal of Forestry Research 2019年第3期30卷 1131-1137页

作者： jong-U Kim Woo-shin lee Eun-Jae lee Department of Forest Sciences Seoul National University Seoul 08826Republic of Korea Urban Planning Research Division Daejeon Sejong Research InstituteDaejeon 34863Republic of Korea

In this study, we examined the use of artificial nest boxes by Siberian flying squirrels (Pteromys volans) in three coniferous and mixed forests in Gangwon Province, South Korea. Six hundred and twelve boxes with different sized entry holes (ranging from 3 to 7 cm in diameter) were placed in the forests between 2004 and 2009. Pteromys volans used nine boxes in the coniferous forests and two boxes in the mixed forests. The squirrels only used boxes with entrance holes measuring 3.5, 4, and 5 cm in diameter, showing a strong and moderate preference for boxes with 5 and 4-cm holes, respectively, and a strong avoidance for boxes with 3- and 7-cm holes. Therefore, we suggest placing artificial nest boxes with entrance holes 5 cm in diameter to encourage breeding activity. Most nests made in the artificial boxes were composed of fibrous materials from woody vines. We recommend placing artificial nest boxes with holes of 5-cm diameter in coniferous forests, which support dense populations of P. volans, to survey whether this approach would positively affect the breeding habits and population maintenance of this species.

关键词： Artificial nest box Coniferous forests Nest materials Siberian flying squirrel Woody vines

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

Electrolyte accessibility of non-precious-metal catalysts with different spherical particle sizes under alkaline conditions for oxygen reduction reaction

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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

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

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