Transparent Conductive Films of Copper Nanofiber Network Fabricated by Electrospinning

Kim, Sungyeoul,Lee, Hyundong,Kim, Dahye,Ko, DaAe,Kim, Dojin,Kim, Hyojin,Yoon, Soon-Gil Hindawi Limited 2015 Journal of nanomaterials Vol.2015 No.-

<P>Cu nanofiber networks can be a good alternative of the Ag nanowire of high electrical conductivity while having the advantage of low price. An electrospinning method was developed to fabricate copper nanofiber network for use as a transparent conductive film on glass substrate. The effects of liquid diluents for electrospinning processability were examined in relation to the subsequent Cu nanofiber formation processes. Electrospinning solutions of copper acetate/polyvinyl alcohol (PVA) and copper nitrate trihydrate/polyvinyl butyral (PVB) were investigated. The polymer mixing solutions influenced the subsequent annealing temperatures for removal of the polymers and reduction of the formed CuO nanofibers to Cu metal nanofibers. The morphology and structures of the formed nanofiber networks were examined by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and so forth. The mixture with PVB provided lower annealing temperatures suitable for application to flexible substrates.</P>

영수증 인식을 활용한 냉장고 내 식품 관리 시스템 개발

김해강(Haekang Kim),서주원(Juwon Seo),손다애(Daae Son),김은민(Eunmin Kim),한규필(Kyuphil Han),오병우(Byoungwoo Oh) 한국정보기술학회 2023 Proceedings of KIIT Conference Vol.2023 No.6

ISDS의 최신 판정 동향: 적법절차를 중심으로

김갑유(Kap-You Kim),조아라(Ara Cho),김다애(Daae Kim) 법무부 국제법무정책과 2020 통상법률 Vol.- No.147

산화철-탄소나노튜브 나노복합체의 암모니아 가스센서 응용

이현동,김다혜,고다애,김도진,김효진,Lee, Hyundong,Kim, Dahye,Ko, DaAe,Kim, Dojin,Kim, Hyojin 한국재료학회 2016 한국재료학회지 Vol.26 No.4

Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with $500^{\circ}C/2h$ oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.

Fully Gravure-Printed D Flip-Flop on Plastic Foils Using Single-Walled Carbon-Nanotube-Based TFTs

Noh, J,Minhun Jung,Kyunghwan Jung,Gwangyong Lee,Joonseok Kim,Soyeon Lim,Daae Kim,Youngchul Choi,Yoonjin Kim,Subramanian, V,Gyoujin Cho IEEE 2011 IEEE electron device letters Vol.32 No.5

<P>Since D flip-flop is one of the indispensable building blocks in integrated circuit (IC) design, providing a successful way to print D flip-flop on plastic foils will be the first step to reach fully printed flexible IC. Here, the network structure of single-walled carbon nanotubes (SWNTs) as an active layer has been employed to print the driver and load thin-film transistors (TFTs) of the D flip-flop. The same physical dimensions of driver and load TFTs were first developed to fully gravure print the D flip-flop because of the advantage of tunable electrical properties of network density of SWNTs. Therefore, the circuit design and printing becomes simpler and more convenient than using general design rules. Furthermore, the SWNT network structure in the active layer can also minimize the fluctuation of threshold voltages (<I>V</I><SUB>th</SUB>) of SWNT-TFTs because of the use of the same physical dimensions in TFTs. The resulting gravure-printed D flip-flop shows a clock-to-output delay of 23 ms for 20-Hz clock signal. This is the first reported D flip-flop performance using all gravure-printing method yet achieved.</P>

Effect of Y-doping on the phase relation and electrical properties of Fe-doped BaZrO₃

Kim, Dongyoung,Lee, Daae,Joo, Jong Hoon Elsevier 2018 Journal of the European Ceramic Society Vol.38 No.2

<P><B>Abstract</B></P> <P>The effects of the co-doping of Y in Fe-doped BaZrO<SUB>3</SUB> (BaZr<SUB>0.7-<I>y</I> </SUB>Fe<SUB>0.3</SUB>Y<I> <SUB>y</SUB> </I>O<SUB>3-</SUB> <I> <SUB>δ</SUB> </I>) on the phase relation and electrical properties are investigated in this study. While a single phase is formed up to <I>y</I> =0.1 by the substitution of Y for Zr-sites (phase-1), the amphoteric substitution of Y for both Zr-sites and Ba-site (phase-2) is observed above <I>y</I> =0.1. Electrical conductivity measurements suggest that <I>p</I>-type conduction prevails under an oxidizing atmosphere. The hole conductivity increases with an increase of Y concentration up to <I>y</I> =0.1, but a further increase of Y concentration causes a decrease in the conductivity. The maximum conductivities of both bulk and grain boundary are obtained at <I>y</I> =0.1, and a further increase of Y concentration leads to a decrease of the conductivity due to the possible formation of phase-2 with the partial replacement of Y for Ba-sites ( Y B a • ). Partial proton conductivity is also improved by Y-doping up to <I>y</I> =0.1, but a further doping cannot contribute to an increase in the proton conductivity. The results indicate that the mixed proton and hole conductivity of Fe-doped BaZrO<SUB>3</SUB> can be improved by the co-doping of a rare-earth acceptor (Y<SUP>3+</SUP>), but the doping level is limited to <I>y</I> =0.1 to avoid the formation of phase-2.</P>

Simultaneous A- and B- site substituted double perovskite (AA’B₂O_5+<i>δ</i>) as a new high-performance and redox-stable anode material for solid oxide fuel cells

Lee, Daae,Kim, Dongyoung,Son, Seung Jae,Kwon, Young-il,Lee, Younki,Ahn, Jou-Hyeon,Joo, Jong Hoon Elsevier 2019 Journal of Power Sources Vol.434 No.-

<P><B>Abstract</B></P> <P>In this study, a novel PrBa<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Fe<SUB>2-x</SUB>Ge<SUB>x</SUB>O<SUB>5+δ</SUB> (PBSFG) double perovskite is first introduced by the co-substitution of Sr for A-sites and Ge for B-sites as a high-performance and redox-stable anode material for solid oxide fuel cells. The modification of the A-sites of PrBaFe<SUB>2</SUB>O<SUB>5+<I>δ</I> </SUB> by Sr-doping (PBSF) significantly enhances electrical conductivity of PBSF under a reducing atmosphere by several orders of magnitude at 800 °C. Subsequently, Ge-doping on B-sites leads to meaningful increases in oxygen ion conductivity of PBSFG, and is owing to increases in the oxygen vacancy concentration. The electrochemical performances of PBSFG-Ce<SUB>0.9</SUB>Gd<SUB>0.1</SUB>O<SUB>2-δ</SUB> (GDC) are evaluated using a composite anode with a GDC|Zr<SUB>0.79</SUB>Sc<SUB>0.2</SUB>Ce<SUB>0.01</SUB>O<SUB>2-δ</SUB> (ScSZ)|GDC electrolyte (~100 μm) and a La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Co<SUB>0.2</SUB>Fe<SUB>0.8</SUB>O<SUB>3-<I>δ</I> </SUB> (LSCF) cathode. The cell shows critical improvement in the maximum power density (838.4 mW cm<SUP>−2</SUP> at 800 °C) relative to the PrBaFe<SUB>2</SUB>O<SUB>5+<I>δ</I> </SUB> composite (497.6 mW cm<SUP>−2</SUP>). Moreover, it shows good redox-cycle stability from fuel to air under a current load.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Simultaneous A- and B-site doped double perovskite is proposed as a new SOFC anode. </LI> <LI> Electrical conductivity is enhanced by A-site modification by Sr doping. </LI> <LI> Oxygen diffusivity is meaningfully improved by B-site modification by Ge doping. </LI> <LI> The anode shows high performance and excellent redox cycle stability. </LI> </UL> </P>

ChemInform Abstract: A New Diarylheptanoid Glycoside from the Stem Bark of Alnus hirsuta and Protective Effects of Diarylheptanoid Derivatives in Human HepG2 Cells.

Park, Daae,Kim, Hyoung Ja,Jung, Seo Yun,Yook, Chang-Soo,Jin, Changbae,Lee, Yong Sup WILEY-VCH Verlag 2010 Chem Inform Vol.41 No.30

<P>ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.</P>

A New Diarylheptanoid Glycoside from the Stem Bark of <i>Alnus hirsuta</i> and Protective Effects of Diarylheptanoid Derivatives in Human HepG2 Cells

Park, Daae,Kim, Hyoung Ja,Jung, Seo Yun,Yook, Chang-Soo,Jin, Changbae,Lee, Yong Sup The Pharmaceutical Society of Japan 2010 Chemical & pharmaceutical bulletin Vol.58 No.2

<P>To search for secondary metabolites of <I>Alnus hirsuta</I> (Betulaceae), various chromatographic separations of the ethyl acetate soluble fraction of the stem bark of <I>A. hirsuta</I> led to the isolation of a new diarylheptanoid glycoside, (3<I>R</I>)-1,7-bis-(4-dihydroxyphenyl)-3-heptanol 3-<I>O</I>-β-<SMALL>D</SMALL>-glucopyranosyl(1→3)-β-<SMALL>D</SMALL>-xylopyranoside (13) and twelve diarylheptanoid derivatives, namely, oregonin (1), rubranoside A (2), hirsutanonol 5-<I>O</I>-β-<SMALL>D</SMALL>-glucopyranoside (3), rubranoside B (4), rubranoside C (5), hirsutanonol (6), hirsutenone (7), (5<I>S</I>)-<I>O</I>-methylhirsutanonol (8), platyphylloside (9), platyphyllonol 5-<I>O</I>-β-<SMALL>D</SMALL>-xylopyranoside (10), aceroside VII (11) and platyphyllenone (12). Isolates were assessed for their hepatoprotective effects against <I>tert</I>-butylhydroperoxide (<I>t</I>-BHP)-induced toxicity in HepG2 cells. Of these isolates, compounds 1—8 showed significant hepatoprotective effects on <I>t</I>-BHP-induced damage to HepG2 cells, with 8 exhibiting the greatest protective effect (50.7±3.7% at a concentration of 10 μ<SMALL>M</SMALL>).</P>

COVID-19 상황에서 재택근무자들의 가족생활 경험 연구

조은숙(Eunsuk Cho),김다애(Daae Kim) 한국가족학회 2021 가족과 문화 Vol.33 No.3

본 연구는 코로나19 팬데믹 상황에서 시작된 재택근무가 당사자 및 가족원의 일상생활과 가족관계에 어떤 변화를 가져왔는지를 재택근무자의 경험을 중심으로 탐색하였다. 이를 위하여 코로나 상황으로 인해 재택근무로 전환된 기혼 성인 연구참여자 7명(남4명, 여3명)을 눈덩이표집법으로 모집하여 온라인 화상 심층면접을 통해 자료를 수집하였다. 면접내용은 전사되었으며 주제분석법(Braun & Clarke, 2006)을 활용하여 분석되었다. 분석결과 재택근무자의 가족생활경험은 5개의 주제, ‘융통성 있는 시간 사용과 시간 여유’, ‘가사노동/자녀돌봄의 증가와 적응’, ‘자녀와 함께 있음으로 인한 정서적 만족’, ‘부부간 다툼도 대화도 많아짐’, ‘가족원의 일상적 면모를 새로 알게 됨’으로 나타났다. 참여자들은 출퇴근 압박 없는 여유로운 삶, 일과 자녀돌봄의 병행이 가능한 점, 자녀와 함께 있을 시간이 늘어난 점, 그리고 함께 있으면서 가족원들이 서로를 더 많이 알게 되는 것 등이 가족관계를 더 풍요롭게 하는 것으로 경험하며 재택근무에 전반적 만족감을 표하였다. 그러나 형편상 가사노동과 자녀 돌봄에 틈틈이 시간을 할애해야 하는 상황에 처한 참여자들은 남녀를 막론하고 재택근무의 불편함을 호소하기도 하였으며 부부간의 사소한 갈등이 이전보다 늘어나기도 하였다. 이러한 결과에 기초하여 연구자들은 재택근무가 ‘일-가족 간 갈등’의 좋은 대안으로 활용되기 위해서는 가사노동과 돌봄노동의 공평한 배분과 건강한 의사소통 등의 가족문화개선이 전제 될 필요가 있음을 논의하였다. This study explored the family life and relationship of telecommunters under the COVID-19 situation. Seven married telecommuters (4 males & 3 females) were recruited through snowballing method, and data were obtained through in-depth interviews using video conference platform(Zoom). Interview transcripts were analyzed using Braun & Clarke(2006)‘s thematic analysis method. The results showed 5 themes: “Flexible time use and time spare,” “Increased domestic labor and child care caused accommodation,” “Emotionally satisfied with being with children,” “Increased quarrel as well as dialogue with partners,” and “Recognized family members’ new aspects”. Participants expressed overall satisfaction with telecommuting, experiencing a relaxed life without commuting pressure, the compatability of work-childcare, increased time being with children, and the fact that family members get to know each other more while being together. However, the participants, who were forced to devote partial time to domestic labor and child care, complained of the uncomfortableness of telecommuting, regardless of gender, and minor conflicts between couples increased than before. Based on these results, authors discussed the need to improve family culture such as fair distribution of domestic and care labor and healthy communication in order to import telecommuting as a good resolution to classic “Work-family conflict.”