• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제36회 동계학술대회 초록집
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• pp.111.2-111.2
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• 2009

• BMB Reports
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• 제32권5호
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• pp.480-485
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• 1999

Tyrosine phenol-lyase of thermophilic Symbiobacterium sp. SC-1, which is obligately and symbiotically dependent on thermophilic Bacillus sp. SK-1, was purified and characterized. The enzyme is composed of four identical subunits and contains approximately 1 mol of pyridoxal 5'-phosphate (PLP) per mol subunit as a cofactor. The enzyme showed absorption maxima at 330 and 420 nm, and lost this absorption profile by treatment with phenylhydrazine. The apparent dissociation constsnt, $K'_D$, for PLP was determined with the apoenzyme to be about $1.2\;{\mu}M$. The isoelectric point was 4.9. The optimal temperature and pH for the $\alpha,\beta$-elimination of L-tyrosine were found to be $80^{\circ}C$ and pH 8.0, respectively. The substrate specificity of the enzyme was very broad: L-amino acids including L-tyrosine, 3,4-dihydroxyphenyl-L-alanine (L-DOPA), L-cysteine, L-serine, S-methyl-L-cysteine, $\beta$-chloro-L-alanine, and S-(o-nitrophenyl)-L-cysteine all served as substrates. D-Tyrosine and D-serine were also decomposed into pyruvic acid and ammonia at rates of 7% and 31% relative to their corresponding L-enantiomers, respectively. D-Alanine, which was inert as a substrate in a, $\beta$-elimination, was the only D-amino acid racemized by the enzyme. The $K_m$ values for L-tyrosine, L-DOPA, S-(o-nitrophenyl)-L-cysteine, $\beta$-chloro-L-alanine, and S-methyl-L-cysteine were 0.19, 9.9, 0.36, 12, and 5.5 mM, respectively.

• Bulletin of the Korean Chemical Society
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• 제23권1호
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• pp.140-142
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• 2002

• 청정기술
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• 제16권1호
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• pp.19-25
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• 2010

결정성의 셀룰로우스를 수소분위기하에서 다양한 귀금속 촉매를 이용하여 폴리올로 전환시키는 연구를 수행하였다. 촉매는 단일 귀금속(Pt, Ru, Ir, Rh, Pd)을 활성탄에 습식함침법으로 담지시켜서 제조하였으며, Pt/$\gamma-Al_2O_3$와 Pt/H-mordenite를 비교촉매로 사용하였다. 생성물은 고압액체크로마토그래피로 분석하였다. 촉매는 질소흡착, X-선 회절법, 유도결합플라즈마분광법(ICP-AES), 수소-승원환원분석($H_2$-TPR), 그리고 일산화탄소 화학흡착을 통하여 분석하였다. 셀룰로우스의 전환율은 사용한 촉매와 연관관계가 낮은 것으로 나타났으며 활성탄에 담지된 귀금속 촉매중에서 Pt/AC가 높은 폴리올의 수득률에 바람직한 것으로 조사되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.275-278
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• 2001

Ferroelectric PZT thin films were fabricated on the RuO$_2$/Pt, Pt bottom electrode with a PZT(53/47) metal alkoxide solutions. All PZT thin films showed a uniform grain structure without the presence of rosette structure. The PZT thin films were etched as a function of Cl$_2$/Ar and additive CF$_4$ into Cl$_2$(80%)/Ar(20%). The etch rates of PZT thin films were 1970 ${\AA}$/min at 30 % additive CF$_4$ into Cl$_2$(80%)/Ar(20%). The remanent polarization and leakage current density in PZT thin film on the RuO$_2$/Pt were 64.2 ${\mu}$C/cm$^2$, 1.4${\times}$10$\^$-6/ respectively.

• 자원리싸이클링
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• 제21권3호
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• pp.15-20
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• 2012

본 논문에서는 연료전지 막전극접합체에서 막분리 및 염산침출법을 이용하여 백금과 루테늄을 침출하는 연구를 하였다. 증류수, 10 vol.% 부탄올 용액, 15 vol.% 양이온 계면활성제(Koremul-LN-7)를 이용하여 연료전지 막전극접합체의 전해질막과 확산층을 침지법으로 촉매입자의 분산 없이 분리하였다. 그리고 질산 또는 과산화수소를 산화제로 하고 사용하는 염산에 의해 분리된 가스확산층의 촉매에 함유된 백금과 루테늄 금속을 침출하는 연구를 하였다. 과산화수소를 산화제로 사용하였을 때 백금과 루테늄의 침출율이 더 높았으며 최적 조건은 $90^{\circ}C$에서 염산 농도 8 M, 과산화수소 첨가량 5 M, 침출시간 6시간이었다. 이 조건에서 백금의 침출률은 98%, 루테늄의 침출율은 71.5%였다.

• Nuclear Engineering and Technology
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• 제30권2호
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• pp.99-111
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• 1998

Chemical composition of the insoluble residue in a simulated spent PWR fuel(SIMRJEL) were studied. SIMFUELS were prepared by adding calculated amount of FP(fission product) elements with a burnup of 3.6% FIMA(fission per initial metal atom) to uranium in nitrate solution, evaporating the mixed solution to dryness, calcining at 90$0^{\circ}C$ in a stream of 4% H$_2$ + 96% He, and heating the pellet at 140$0^{\circ}C$ under high and low oxygen potentials. Insoluble residue was obtained from the dissolution of the SIMFUEL with HNO$_3$(1 : 1). The chemical composition of the SIMFUELs and the insoluble residues was determined by EPMA(electron probe microanalysis), XPS(X-ray photoelectron spectroscopy) and by XRD (X-ray diffraction) measurements. All of the insoluble residues suspended and precipitated were composed mainly of Mo, Ru with a small amount of Zr, Rh, Pd and Cd. The amount of insoluble residue(<1 wt.%) and a Mo/Ru ratio decreased with increasing oxygen potential. Formation of the zirconium molybdate precipitate, ZrMo$_2$O$_{7}$(OH)$_2$($H_2O$)$_2$, was observed in the residues. The possible role of Mo on the phase formation was discussed in regard to oxygen potential.l.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.40.2-40.2
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• 2007

• 한국진공학회:학술대회논문집
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• 한국진공학회 1997년도 제12회 학술발표회 논문개요집
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• pp.38-38
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• 1997

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.52.2-52.2
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• 2007