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Structural and Electrical Properties of (Ba,Sr,Ca)TiO3 Thick Films doped with Dy 2O3 (Dy2O3를 첨가한 (Ba,Sr,Ca)TiO3 후막의 구조 및 전기적 특성 연구)

  • Noh, Hyun-Ji;Park, Sang-Man;Yun, Sang-Eun;Lee, Sung-Gap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.8
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    • pp.680-684
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    • 2007
  • In this study, we investigated the effects of structural and electrical properties of $(Ba_{0.6},\;Sr_{0.3},\;Ca_{0.1})TiO_3$ thick films with variation $Dy_2O_3$ contents. $(Ba_{0.6},\;Sr_{0.3},\;Ca_{0.1})TiO_3$ powders, prepared by the sol-gel method, were mixed organic vehicle. The BSCT thick films doped with 0.1, 0.3, 0.5, 0.7 mol% $Dy_2O_3$ were fabricated by the screen-printing techniques on the alumina substrates and the structural and dielectric properties were investigated with variation of $Dy_2O_3$ doping contents. All BSCT thick films were sintered at $1420^{\circ}C$, for 2hr. In the TG-DTA analysis, the formation of the polycrystalline perovskite phase was observed at around $670 ^{\circ}C$. In the XRD analysis, all BSCT thick films showed the cubic perovskite structure. The average thickness of BSCT thick films was approximately $65{\mu}m$. The Curie temperature decreased with increasing $Dy_2O_3$ amount. The relative dielectric constant and dielectric loss of BSCT thick films doped with $Dy_2O_3$ 0.1 mol% were 6267 and 2.6 %, respectively.

Development of Mixed Conducting Ceramic Membrane for High Purity Hydrogen and Carbon Production from Methane Direct Cracking (복합전도성 세라믹 분리막의 탄화수소 직접분해에 의한 고순도 수소와 탄소 제조)

  • Kim, Ji-Ho;Choi, Duck-Kyun;Kim, Jin-Ho;Cho, Woo-Seok;Hwang, Kwang-Taek
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.5
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    • pp.649-655
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    • 2011
  • Methane direct cracking can be utilized to produce $CO_x$ and $NO_x$-free hydrogen for PEM fuel cells, oil refineries, ammonia and methanol production. We present the results of a systematic study of methane direct cracking using a mixed conducting oxide, Y-doped $BaZrO_3$ ($BaZr_{0.85}Y_{0.15}O_3$), membrane. In this paper, dense $BaZr_{0.85}Y_{0.15}O_3$ membrane with disk shape was successfully sintered at $1400^{\circ}C$ with a relative density of more 93% via addition of 1 wt% ZnO. The ($BaZr_{0.85}Y_{0.15}O_3$) membrane is covered with Pd as catalyst for methane decomposition with an DC magnetron sputtering method. Reaction temperature was $800^{\circ}C$ and high purity methane as reactant was employed to membrane side with 1.5 bar pressure. The $H_2$ produced by the reaction was transported through mixed conducting oxide membrane to the outer side. In addition, it was observed that the carbon, by-product, after methane direct cracking was deposited on the Pd/ZnO-$BaZr_{0.85}Y_{0.15}O_3$ membrane. The produced carbon has a shape of sphere and nanosheet, and a particle size of 80 to 100 nm.

Structural and Dielectric Properties of (Ba,Sr,Ca)$TiO_3$ Thick films Doped with $Dy_{2}O_{3}$ ($Dy_{2}O_{3}$가 첨가된 (Ba,Sr,Ca)$TiO_3$ 후막의 구조 및 유전 특성)

  • Yun, Sang-Eun;Lee, Sung-Gap;Park, Sang-Man;Noh, Hyun-Ji;Lee, Young-Hie;Bae, Seon-Gi
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1275-1276
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    • 2007
  • For fabrication of $BaTiO_3$ system Ferroelectric thick films, (Ba,Sr,Ca)$TiO_3$ (BSCT) powders, prepared by using the alkoxide-based sol-gel method, were doped $MnCO_3$ as acceptor and $Dy_{2}O_{3}$ as donor. $MnCO_3$ and $Dy_{2}O_{3}$-doped (Ba,Sr,Ca)$TiO_3$ thick films were fabricated by screen printing techniques on high purity alumina substrates. The structure and dielectric properties were investigated with variation of $Dy_{2}O_{3}$ amount. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure and no pyrochlore phase was observed. The average grain size and thickness of specimens no doped with $Dy_{2}O_{3}$ was 1.32mm, 52mm, respectively. The relative dielectric constant decreased and dielectric loss increased with increasing amount of $Dy_{2}O_{3}$ dopant, the values of the BSCT thick films no doped with $Dy_{2}O_{3}$ were 4043 and 0.4% at 1 kHz, respectively. The relative dielectric constant gradually decreased in the measured frequency range from 0.1 to 100 kHz

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Effects of Tree-spray of Calcium Agent, Coating Agent, GA4+7 + BA and Paper Bagging on Russet Prevention and Quality of 'Gamhong' Apple Fruits (칼슘제, 피막제, GA4+7 + BA의 수체살포 및 봉지씌우기에 의한 '감홍' 사과의 동녹 방지와 과실품질)

  • Moon, Young-Ji;Nam, Ki-Woong;Kang, In-Kyu;Moon, Byung-Woo
    • Horticultural Science & Technology
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    • v.34 no.4
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    • pp.528-536
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    • 2016
  • This study was conducted to examine the effect of 0.4% of $CaCl_2$, $2H_2O$, $1mg{\cdot}L^{-1}$ of Calmodulin (CaM)-SH, 250-folds of coating agent (WE-36), 1,000-folds of $GA_{4+7}+BA$ and 3 types of paper bagging treatments on russet incidence and fruit quality attributes of 'Gamhong' apple. The pattern of russet occurrence was slightly different for 4 years (from 2012 to 2015) in 'Gamhong' apple. The russet occurrence was lowest in $GA_{4+7}+BA$ treatment at 20 days after full bloom (DAFB), compared with other treatments. The $GA_{4+7}+BA$ treatment increased fruit weight at 20 DAFB, while the other fruit quality attributes were not influenced. The russet occurrence was lower not only in a single bag application than in untreated ones but also in yellow bagging and discolored bagging applications than in a white bagging application. The russet occurrence in a bagging application was lower at 20 DAFB than at 30 and 40 DAFB, while fruit quality attributes were not affected by bagging applications. The russet incidence was lower in $GA_{4+7}+BA$ twice treatments at 20 and 30 DAFB, and calcium coated bag at 30 DAFB after $GA_{4+7}+BA$ treatment at 20 DAFB than in untreated fruit. The rate of russet incidence was lowest at equator region in $GA_{4+7}+BA$ treatment, compared with the other fruit regions. Overall, the results suggest that one and/or two applications of $GA_{4+7}+BA$ (1,000-folds) treatment at 20 DAFB should reduce the risk of russet incidence in 'Gamhong' fruit.

Simultaneous Detection of Barley Virus Diseases in Korea (국내 맥류에 발생하는 바이러스병 동시진단 방법)

  • Lee, Bong-Choon;Bae, Ju-Young;Kim, Sang-Min;Ra, Ji-Eun;Choi, Nak Jung;Choi, Man Young;Park, Ki Do
    • Research in Plant Disease
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    • v.23 no.4
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    • pp.363-366
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    • 2017
  • Barley mild mosaic virus (BaMMV), Barley yellow mosaic virus (BaYMV) and Barley yellow dwarf virus (BYDV) have been identified as an important causative agents for an economically important disease of winter barley in Korea. In this study, a multiplex reverse transcription polymerase chain reaction (mRT-PCR) method was used for the simultaneous detection. Three sets of virus-specific primers targeted to the capsid protein coding genes of BaMMV, BaYMV and BYDV were used to amplify fragments that were 594 bp, 461 bp, and 290 bp, respectively. Several sets of primers for each target virus were evaluated for their sensitivity and specificity by multiplex RT-PCR. The optimum primer concentrations and RT-PCR conditions were determined for the multiplex RT-PCR. The mRT-PCR assay was found to be a better and rapid virus diagnostic tool of specific barley diseases and potential for investigating the epidemiology of these viral diseases.