• 열처리공학회지
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• 제27권4호
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• pp.180-184
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• 2014

In order to make clear relationship between high temperature tensile properties and fine microstructure of rapidly solidified cast-type Ni-base superalloys without heat treatment required for consolidation process, tensile test was carried out by changing strain rate from $5{\times}10^{-5}s^{-1}$ to $2{\times}10^{-2}s^{-1}$ and test temperature from $900^{\circ}C$ to $1050^{\circ}C$ using IN738LC and Rene'80 melt-spinning ribbons by twin roll process which were superior to ribbons by single roll process from the viewpoint of structure homogeneity. The dependence of tensile strength on strain rate and test temperature was studied and strain rate sensitivity, m, were estimated from tensile test results. From this study, it was found that tensile strength was influenced by ${\gamma}^{\prime}$ particle diameter, test temperature and strain rate, and m of ribbons exhibited above 0.3 over $950^{\circ}C$.

• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.109-113
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• 2015

초임계 이산화탄소 발전 시스템 구축을 위해서는 고온, 고압의 열악한 환경에 노출되는 터빈, 열 교환기, 압축기와 같은 핵심 부품들의 내식성 평가는 반드시 수행되어야 한다. 이를 위해 후보소재 3종 Ferritic-Martensitic Steel (T92), Austenitic Steel (SS316L), Ni-based Alloy (IN738LC)를 선정하여 고온의 유사 초임계 $CO_2$ 발전 환경에서의 내식성 평가를 진행하였다. $600^{\circ}C$, $700^{\circ}C$의 2개의 온도 구간에서 $CO_2$ 분위기를 조성하여 800 시간 동안 노출시킨 뒤, Weight Change, Surface Morphology, Cross Section, Composition을 분석하였다. Cr-rich Protective Layer를 형성하는 Ni-based Alloy와 Fe/Cr-rich oxide를 형성하는 Austenitic Steel은 우수한 부식 저항성을 보인 반면에 Ferritic-Martensitic Steel은 높은 Weight Change와 Fe-rich Non-Protective Oxide가 관찰되어 상대적으로 낮은 부식 저항성을 보였다.

• Genomics & Informatics
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• 제8권1호
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• pp.50-57
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• 2010

Mercuric chloride, a model nephrotoxicant was used to elucidate time- and dose- dependent global gene expression changes associated with proximal tubular toxicity. Rat kidney cell lines NRK-52E cells were exposed for 2, 6 and 12 hours and with 3 different doses of mercuric chloride. Cell viability assay showed that mercuric chloride had toxic effects on NRK-52E cells causing 20% cell death (IC20) at $40{\mu}M$ concentration. We set this IC20 as high dose concentration and 1/5 and 1/25 concentration of LC20 were used as mid and low concentration, respectively. Analyses of microarray data revealed that 738 genes were differentially expressed (more than two-fold change and p<0.05) by low concentration of mercuric chloride at least one time point in NRK-52E cells. 317 and 2,499 genes were differentially expressed at mid and high concentration of mercuric chloride, respectively. These deregulated genes showed a primary involvement with protein trafficking (CAV2, CANX, CORO1B), detoxification (GSTs) and immunity and defense (HMOX1, NQO1). Several of these genes were previously reported to be up-regulated in proximal tubule cells treated with nephrotoxicants and might be aid in promoting the predictive biomarkers for nephrotoxicity.