• 한국미생물·생명공학회지
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• 제24권6호
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• pp.687-692
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• 1996

Xylanase (EC 3.2.1.8) was purified approximately 4.3 fold from Aspergillus niger SFN-416 by ammonium sulfate fractionation, Sephadex G-100 gel filtration and DEAE-Sephacel ion exchange chromatography. Molecular weight of the enzyme was approximately 42,000 daltons. The optimum pH and temperature of the enzyme activity were 5.5 and 50$\circ$C, respectively. The enzyme activity was enhanced by Fe$^{2+}$, and inhibited by Hg$^{2+}$. The activity was decreased by addition of methanol, ethanol, isopropanol and 1-butanol at a concentration of 10%(v/v).

• Mycobiology
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• 제32권2호
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• pp.74-78
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• 2004

An alkaline protease produced by Aspergillus niger C-15 was purified and characterized. The enzyme was purified 19.41-fold with a specific activity of 74150 U/mg and a recovery of 34.4% by gel filtration and ion exchange chromatography. The molecular weight of the enzyme was estimated to be 34 kDa. The optimum pH and temperature for the protease activity were pH 8.0 and $60^{\circ}C$, respectively. The enzyme activity inhibited by EDTA suggests that the preparation contains a metalloprotease. The enzyme activity of the metalloprotease was completely inhibited by 5 mM $HgCl_2$ and $FeCl_3$, while partially inhibited by $CuSO_4$, and $MnCl_2$. When polyols such as glycerol, mannitol, sorbitol and xylitol, were added to the reaction medium, most polyols tested enhanced protease activity. Especially, glycerol showed the highest effect. The alkaline metalloprotease was stable at high temperature and retained more than 90% of the initial activity at $60^{\circ}C$ and 86.4% under addition of glycerol.

• 한국재료학회지
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• 제12권6호
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• pp.427-430
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• 2002

Plasma nitrocarburizing treatment was performed for SCM 435 steel by using a plasma ion nitriding system. The effects of the variation of nitrogen and methan contents upon the hardened layer was investigated. Both the thickness of the compound layer and the amount of $\varepsilon$ phase in the compound layer increased with increasing nitrogen content. However, the thickness of the compound layer decreased due to unstable plasma for an atmosphere containing 90% $N_2$ gas content in the gas mixture. The amount of $\varepsilon$phase in the compound layer increased with increasing $CH_4$ gas content. For $CH_4$ gas content more than 2% in the gas mixture, the thickness of the compound layer decreased due to the formation of $\theta$ phase.

• KSBB Journal
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• 제8권2호
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• pp.110-114
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• 1993

Vinblastine, an anticancer agent was produced by chemical coupling of two different monomeric indole alkaloids, vinblastine and catharanthine in the presence of ferric ion. Vindoline was efficiently extracted from the leaves of vinca (Cafharanthus roseus) by using supercritical carbon dioxide, whereas catharanthine was chemically extracted from the in vitro cultured hairy roots. The extracted crude monomeric precursors were purified by a two-step preparative TLC. The coupling reaction was carried out in the 0.1M glycine buffer(pH 2.0, 5ml) containing 40mM FeC13 with purified vindoline(0.3mg) and catharanthine(0.3mg) at 4$^{\circ}C$. The production yields (weight %) of vinblastine and 3', 4'-anhy-drovinblastine in the products were 23.2 and 26.0, respectively. The produced vinblastine was confirmed by FAB-MS.

• Journal of Applied Biological Chemistry
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• 제44권2호
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• pp.71-76
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• 2001

Methanol extract and solvent fractions of Aster scaber Thunb. were tested to elucidate antioxidative characteristics in vitro. Methanol extract showed strong inhibition on linoleic acid autoxidation and conjugated diene production. Hexane and diethyl ether fractions showed stronger chelating effect on $10^{-4}M\;FeCl_3$ than the other fractions. Butanol fraction had the strongest capacity on $10^{-3}M\;CuSO_4$ similar to ${\alpha}$-tocopherol. Synergistic effect of butanol fraction with histidine, methionine, and lysine on linoleic acid autoxidation had been observed. Contents of total phenol, vitamin E, vitamin C, and carotenoid were evaluated. From the results, Aster scaber Thunb. could be expected to play a role as an antioxidant in vivo.

• Fibers and Polymers
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• 제7권2호
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• pp.105-111
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• 2006

Coating the fibre surface by in situ oxidative chemical polymerisation of polypyrrole (using $FeCl_3$ as oxidant) is a readily industrial applicable way to give electrical properties to wool with good ageing stability [1], although pre-treatments are required to avoid damage of the cuticle surface due to the acidic condition of the process. FT-IR and EDX analysis reveal that organic sulphonates and sulphates, used as dopants, are absorbed by wool, while chlorine ions are preferably embedded on the polypyrrole layer. The resulting electrical conductivity seems mainly due to the presence of chlorine as counter-ion of polypyrrole; nevertheless, the presence of arylsulphonate in the polymerisation bath increases the electrical conductivity of the coating layer.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.309-310
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• 2005

Some minor elements(Al, B, Ba, Ca, Cd, Co, Cr, Cu, Gd, Mg, Mn, Mo, Nd, Ni, P, Pb, Si, Sn, Sr, Ti, V, Yb, Zn and Zr) in iron compounds such as the S/G sludge of a power plant were separated from iron by anionic and cationic exchange methods. If a ICP-AES or AAS determination follows this method, minor elements of more than 2 or 20 ppm of Fe can be determined with an error less than 20% except Sn and Mo. Alkaline elements were excluded from this study since they can be easily recovered from an anionic exchange. Application to real sludge samples is ongoing.

• 한국의류산업학회지
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• 제5권3호
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• pp.283-288
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• 2003

Large quantity of metal mordant in natural dyeing has been used. For environmental reason, there is a need to reduce the amount of metal mordant and suggest the optimum amount of metal mordant in dyeing process. In this study, the relationship between mordant concentration and dyeing property was investigated. Various metal mordant concentrations of AI, Cu, Fe, Sn, were studied (from 1 to 5%). After treatment of mordant on cotton fabric, the concentration of metal ion in used mordant solution was quantified. There was no significant difference of the tone of color in mordant concentration from 1% to 5%, Therefore, there is no need to increase mordant concentration over 1%. chitosan treated cotton fabric showed a significant increase in dyeing affinity compared to untreated cotton fabric (the value of ${\Delta}E$ was 20). chitosan increased dye affinity significantly in the presence of mordant. It can be suggested that chitosan itself can replace metal mordants in the future.

• 약학회지
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• 제47권6호
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• pp.356-360
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• 2003

Nitroso-2-naphthol-3,6-disulfonic acid, disodium salt (NRS) was used as an organic ligand to prepare basic drug-selective polymeric membrane electrode. The sensing membrane of the electrode consited of basic drug-meta1(II)-NRS as an ion-exchanger site in a poly(vinyl chloride) matrix plasticized with 2-nitrophenyl octyl ether (NPOE). The metal ions used were Fe$^{2+}$, Co$^{2+}$, Ni$^{2+}$ and Cu$^{2+}$. The electrodes exhibited fast and wide linear response in the basic drug concentration of 10$^{-5}$ ∼10$^{-3}$ mol/l with a response slope of 50∼60 mV/decade in a buffer solution of pH 4∼8. The electrodes exhibited good selectivity for many basic compounds.mpounds.

• 한국세라믹학회지
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• 제37권11호
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• pp.1065-1070
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• 2000

TiO$_2$의 첨가가 Mn-Zn ferrites의 전자기적 물성에 미치는 효과에 대해 연구하였다. TiO$_2$의 첨가량이 증가함에 따라 밀도와 전기비저항이 증가된 반면 초기투자율은 감소하였다. TiO$_2$의 첨가에 따라 Fe$^{2+}$ ion의 증가에 기인하여 전력손실의 최소 값을 나타내는 온도가 저온으로 이동하였다. TiO$_2$를 0.12wt% 첨가한 시편의 경우, 100 kHz, 200 mT, 8$0^{\circ}C$ 측정 조건에서는 소결온도가 증가함에 따라 전력손실이 감소하였으며 125$0^{\circ}C$ 소결한 시편이 340 mW/㎤으로 가장 낮은 값을 보였다. 500 kHz, 50 mT, 8$0^{\circ}C$의 측정 조건에서는 소결 온도가 감소함에 따라 전력손실이 감소하였으며 115$0^{\circ}C$ 소결한 시편이 105 mW/㎤으로 가장 낮은 전력손실 값이 관찰되었다.