• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.740-746
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• 2007

The potential candidates for IT-SOFCs cathode materials, $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) and $La_{0.6}Ba_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LBCF) powders, were synthesized by a EDTA-citrate combined method from $Sr(NO_3)_2$, $Ba(NO_3)_2$, $La(NO_3)_3{\cdot}6H_2O$, $Co(NO_3)_2{\cdot}6H_2O$, $Fe(NO_3)_3{\cdot}9H_2O$, citric acid and $EDTA-NH_3$. The cathode performance of symmetrical electrochemical cells consisting of BSCF-GDC or LBCF-GDC composite electrodes and a GDC electrolyte was investigated using by AC impedance spectroscopy at the temperature range of 500 to $700^{\circ}C$. It was found that a single phase perovskite could be successfully synthesized when the precursor is heated at $850^{\circ}C$ for 2 h. Due to thermal expansion mismatch between BSCF and GDC, the composite cathodes with lower GDC content than 45 wt% were peeled off from the GDC electrolyte and their electrode polarization resistance was estimated to be high. The thermal expansion coefficient of BSCF-GDC composites was decreased with increasing the GDC content and the electrode peeling off did not occur in BSCF-45 and 55 wt% GDC composites. BSCF-45 wt% GDC composite electrode showed the lowest area specific resistances (ASR) of 0.15 and $0.04{\Omega}{\cdot}cm^2$ at 600 and $700^{\circ}C$, respectively. On the other hand, LBCF-GDC composite cathodes showed higher ASR than the BSCF-45 and 55 wt% GDC and their cathode performance were decreased with the GDC content.

• Journal of Plant Biotechnology
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• v.42 no.3
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• pp.228-234
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• 2015

Using either the apical or axillary bud of the endangered species Abeliophyllum distichum Nakai, we tested the effect of bud position and culture method on shoot proliferation and rooting. In shoot proliferation, the axillary bud explant was more effective than the apical bud and the effect was fostered by BA treatment, whereas no differences were observed in shoot elongation by the explant position. Spontaneous rooting was observed in the MS basal medium and resulted in conspicuous differences in the explant position : more than 80% in apical bud explant and 28% in axillary bud explant was achieved, respectively. The positional effects were also observed in BA pre-treatments: generally vertical culture method appeared to be better in shoot proliferation, growth, and rooting than that of the horizontal culture method regardless of the BA pre-treatment duration. The highest shoot multiplication was achieved through the vertical culture method with axillary bud explant, whereas the best shoot elongation and rooting was obtained using the vertical culture method with the apical bud explant. Apical bud explant was superior to axillary bud explant in ex vitro micro-cuttings and revealed a significant difference in shoot growth and root development. The above results suggest that explant position and culture method influence the efficiency of micropropagation for a rare and endangered plant Abeliophyllum distichum.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.559-563
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• 2016

Recently, a barium(Ba) and an iodine(I) being studied as a conventional lead(Pb) alternatives of shielding material has excellent shieding rate, but the characteristic x-ray photons in the energy range near 30 keV line is released. In this study, with bismuth oxide(BiO) coupled barium sulfate($BaSO_4$) double layer, transmitted spectra, shieding rates and relative weighting rates were evaluated to validate the applicability of eco-friendly double layer shieding structure using monte carlo simulations as a prior study. From the evaluation results, in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer, the shieding rate showed 1.9% and 3.9% higher than 0.6mm thickness of Pb single layer, respectively. In addition, the relative weight also 28% and 34.5% lower than 0.6mm-Pb in 0.4mm and 0.5mm thickness of BiO layers coupled with top 0.1mm-$BaSO_4$ layer.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.271-277
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• 2014

To overcome the limitations of the solid oxide fuel cells (SOFCs) due to the high temperature operation, there has been increasing interest in proton conducting fuel cells (PCFCs) for reduction of the operating temperature to the intermediate temperature range. In present work, the perovskite $BaCe_{0.85-x}Zr_xY_{0.15}O_{3-\delta}$ (BCZY, x = 0.1, 0.3, 0.5, and 0.7) were synthesized via solid state reaction (SSR) and adopted as an electrolyte materials for PCFCs. Powder characteristics were examined using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer, Emmett and Teller (BET) surface area analysis. Single phase BCZY were obtained in all compositions, and chemical stability was improved with increasing Zr content. Anode-supported cell with $Ni-BaCe_{0.55}Z_{0.3}Y_{0.15}O_{3-\delta}$ (BCZY3) anode, BCZY3 electrolyte and BCZY3-$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-\delta}$ (BSCF) composite cathode was fabricated and electrochemically characterized. Open-circuit voltage (OCV) was 1.05 V, and peak power density of 370 ($mW/cm^2$) was achieved at $650^{\circ}C$.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.177-183
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• 2016

The present study was conducted to establish the suppression condition of lateral root development for producing high-quality peanut sprouts. The result of Chamsiru or 6BA treatment on peanut sprouts 'Jopyeong' and 'Vietnam' showed that the higher concentration of the solutions showed the better effect for suppressing lateral root development, regardless of the kinds of lateral root inhibitor. Compared to Chamsiru, 6BA showed better effect for suppressing lateral root development, and the effect was more obvious for 'Jopyeong' than 'Vietnam'. The alternant irrigation of Chamsiru and 6BA solution could produce high-quality peanut sprouts by inhibiting bacteria activity in solution and promoting of hypocotyl and root growth, while suppressing the lateral root development. The treatment of mixture solution of $GA_3$ and Chamsiru improved the overall growth of peanut sprouts, and the effect was the highest in the treatment of '$GA_3\;50mg{\cdot}L^{-1}$ + Chamsiru $8.40mg{\cdot}L^{-1}$'.

• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.301-305
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• 2016

We investigate proton conduction in a nonstoichiometric ${\Sigma}3$ $BaZrO_3$ (210)[001] tilt grain boundary using density functional theory (DFT). We employ the space charge layer (SCL) and structural disorder (SD) models with the introduction of protons and oxygen vacancies into the system. The segregation energies of proton and oxygen vacancy are determined as -0.70 and -0.54 eV, respectively. Based on this data, we obtain a Schottky barrier height of 0.52 V and defect concentrations at 600K, in agreement with the reported experimental values. We calculate the energy barrier for proton migration across the grain boundary core as 0.61 eV, from which we derive proton mobility. We also obtain the proton conductivity from the knowledge of proton concentration and mobility. We find that the calculated conductivity of the nonstoichiometric grain boundary is similar to those of the stoichiometric ones in the literature.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.1050-1053
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• 2009

상용화 되고 있는 Pt/BaO/$Al_2O_3$촉매에 Iron을 첨가량에 따른 흡장량의 증가를 알아내기 위한 실험을 실행하였다. $SO_2$를 포함하고 있는 배기가스중의 NOx를 제거하기 위해 SOx 존재 하에서 Pt/Co/BaO/$Al_2O_3$촉매에 Iron량을 증감하여 흡장량을 비교분석하였으며, 10%에서 높은 흡장 면적을 나타내었다. XRD와 BET 결과 고온 소성시 흡장량 감도는 Pt의 열화 소결이 원인인 것으로 나타난다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.19-21
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• 1993

The perovskite type ferroelectrics has been studied to make a flim out of ceramic capacitor with large capacity and miniaturization. In this study. we make a capacitor in small size and high capacity, and measure SEM and dielectric permitivity of BCTM ceramic capacitor.

• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.94-94
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• 2007

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1504-1506
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• 2002

$(Ba_{0.6-x}-Sr_{0.4}Ca_x)TiO_3$ (x=0.10, 0.15, 0.20, y=$0.0{\sim}3.0$) powders were fabricated by the sol-gel method, and BSCT thick films were fabricated by the silk-screen printing method. Their structural and dielectric properties were investigated with variation of composition ratio. All BSCT thick films showed a homogeneous structure without presence of the second phase. BSCT film thickness, obtained by three cycle of printing, was approximately $80{\mu}m$. The dielectric constant and dielectric loss of the 3-coated BSCT(50/40/10) thick film were approximately 1700 and 0.07%, respectively.