• Bulletin of the Korean Chemical Society
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• 제23권11호
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• pp.1664-1666
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• 2002

• 열처리공학회지
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• 제14권2호
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• pp.103-109
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• 2001

Plasma nitrocarburising and post oxidation were performed on SM45C steel using a plasma nitriding unit. Nitrocarburising was carried out with various methane gas compositions with 4 torr gas pressure at $570^{\circ}C$ for 3 hours and post oxidation was carried out with 100% oxygen gas atmosphere with 4 torr at different temperatures for various times. It was found that the compound layer produced by plasma nitrocarburising consisted of predominantly ${\varepsilon}-Fe_{2-3}(N,C)$ and a small proportion of ${\gamma}-Fe_4(N,C)$. With increasing methane content in the gas mixture, ${\varepsilon}$ phase compound layer was favoured. In addition, when the methane content was further increased, cementite was observed in the compound layer. The very thin oxide layer on top of the compound layer was obtained by post oxidation. The formation of Oxide phase was initially started from the magnetite($Fe_3O_4$) and with increasing oxidation time, the oxide phase was increased. With increasing oxidation temperature, oxide phase was increased. However the oxide layer was split from the compound layer at high temperature. Corrosion resistance was slightly influenced by oxidation times and temperatures.

• 한국재료학회지
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• 제14권4호
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• pp.265-269
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• 2004

Plasma nitrocarburising and post oxidation were performed on SCM435 steel by a pulsed plasma ion nitriding system. Plasma oxidation resulted in the formation of a very thin ferritic oxide layer 1-2 $\mu\textrm{m}$ thick on top of a 15～25 $\mu\textrm{m}$ $\varepsilon$-F $e_{2-3}$(N,C) nitrocarburized compound layer. The growth rate of oxide layer increased with the treatment temperature and time. However, the oxide layer was easily spalled from the compound layer either for both oxidation temperatures above $450^{\circ}C$, or for oxidation time more than 2 hrs at oxidation temperature $400^{\circ}C$. It was confirmed that the relative amount of $Fe_2$$O_3$, compared with $e_3$$O_4$, increased rapidly with the oxidation temperature. The amounts of ${\gamma}$'-$Fe_4$(N,C) and $\theta$-$Fe_3$C, generated from dissociation from $\varepsilon$-$Fe_{2-3}$ /(N,C) phase during $O_2$ plasma sputtering, were also increased with the oxidation temperature.e.

• 열처리공학회지
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• 제7권3호
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• pp.206-218
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• 1994

In 50%$NH_3+Air+N_2$ atmospheres, the effect of air additions on the growth characteristics of the compound layer during oxynitriding at $570^{\circ}C$ for 2hr in carbon and alloy steels has been investigated. The ammount of apparent residual ammonia during oxynitriding has shown to be increased with air additions(9~36 Vol. %) and X-ray diffraction analysis of case oxynitreded has shown that the compound layer consist of ${\varepsilon}-Fe_{2-3}$(N, C) phase and ${\gamma}^{\prime}-Fe_4$(N,C) phase. In the case of carbon steels, the thickness of oxide layer, compound layer and porous layer and the amount of ${\varepsilon}-Fe_{2-3}$(N,C) phase in the compound layer were increased with additions of air in 50%$NH_3+N_2$ atmospheres. At the same gas composition, the thickenss of oxide layer, compound layer and porous layer in alloy steels showed slightly thin layer thickness compared to those of carbon steels and the ${\gamma}^{\prime}-Fe_4$(N,C) phase in the compound layer of alloy steels was found barely. Therefore, the most obvious effect of air addition in the gas nitriding atmosphere has been found to in crease further kinetics of nitriding reaction.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.448-452
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• 2001

An Experimental study was carried out to develop a simple method of processing copper waste sludge which is produced by PBC manufacturing. The procedure is based on leaching of wet sludge in 2N H$_2$SO$_4$, and the solid / liquid ratio is controlled approximately at 1/10. The recovery of copper is 85.4%, and pH of the leachate is 3.20. Adding ammonia solution into leachate forms ammine, and hydroxide compounds derived from other impurities in leachate at pH 10. The hydroxide compound can be treated by ferrite process, and the product is a stable oxide compound. Then the ammine solution is heated to evaporate ammonia, and the copper hydroxide is formed. Heating at 8$0^{\circ}C$by aeration, copper hydroxide is transformed into copper oxide with a purity of 98.4%. This process can recover most copper from sludge and the residue can be stabilized by the formation of a stable oxide compound which is not hazardous to environment.

• 한국표면공학회지
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• 제55권2호
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• pp.84-90
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• 2022

With the growing interest in energy storage and conversion systems including secondary batteries, capacitors, and water electrolysis, various electrode materials are being developed to improve the energy efficiency. Among them, graphene is regarded as one of the promising candidates owing to its exceptional properties - large surface area, and excellent electrical conductivity. Herein, we report a facile one-step electrochemical approach to synthesize exfoliated graphene/Fe oxide compound. The effect of experimental conditions - the types of applied voltage, kinds of counter electrodes, acidity of electrolyte on the synthesis of graphene/Fe oxide compound is investigated.

• 한국유기농업학회지
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• 제22권3호
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• pp.469-481
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• 2014

본 연구진은 신규 미생물인 Nocardia sp. CS682 균주에서 항균물질인 nargenicin을 확보하고, 그 유도체 5종을 확보하여 그람양성, 음성 및 다약제 내성균에 대한 항균 효능 및 LPS로 자극된 대식세포에서의 nitric oxide 생성 억제능을 확인하였다. Nargenicin 유도체들은 nargenicin 및 vancomycin에 비교하여 우수한 항균 활성을 보여주었으며, compound 4 및 5는 광범위한 항균 효능 외에 nitric oxide 생성 억제능을 보여 항균-항염효과를 가지는 dual effector로써 감염, 면역 질환에 응용 가능성을 시사하였다. Nargenicin 유도체들은 향후 염증반응에서의 면역 조절 기작에 대한 추가 연구가 필요할 것으로 사료된다.

• 생명과학회지
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• 제28권5호
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• pp.509-516
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• 2018

노각나무(Stewartia koreana) 잎 에틸아세테이트 분획으로부터 quercetin (1), quercitrin (2), hyperin (3), quercetin-3-O-(6"-O-galloyl)-${\beta}$-D-galactopyranoside (4), kaempferol-3-o-[2",6"-di-o-(trans-p-coumaroyl)]-${\beta}$-D-glucopyranoside (5)의 5종의 플라보노이드를 분리하였으며, 이들 5종 성분의 염증 반응에 대한 활성을 분석하기 위하여 LPS를 처리한 대식세포에서 산화질소(NO) 생성 억제활성을 측정하였다. 이들 5종 성분 중 compound 4, 5는 노각나무에서 처음으로 분리된 것으로 항염증 활성에 대한 보고도 없다. 분광분석법으로 확인된 노각나무 잎 유래 성분들은 LPS 처리한 대식세포의 NO 생성을 유의적으로 저해하였으며, 특히 kaempferol-3-o-[2",6"-di-o-(transp-coumaroyl)]-${\beta}$-D-glucopyranoside (5)는 가장 강한 억제효과(17.17%, 5.0%, 3.92%, 6.32% and 63.35% inhibition of compound 1, 2, 3, 4 and 5 at $10{\mu}g/ml$)를 나타냈다. 또한, 이러한 NO 생성 억제효과는 inducible nitric oxide synthase(iNOS) 단백질 발현 억제를 통한 것으로 나타났다. 따라서, 본 연구에서 새로 분리된 플라보놀인 kaempferol-3-o-[2",6"-di-o-(trans-p-coumaroyl)]-${\beta}$-D-glucopyranoside (5)는 노각나무 잎의 항염증 활성을 나타내는 주요 물질로 사료된다.

• 한국재료학회지
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• 제14권5호
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• pp.322-327
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• 2004

Copper-based leadframe sheets were oxidized in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched Brazil-nut (SBN) specimens. The SBN specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under mixed-mode (mode I + mode II) loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The results revealed that the failure paths were strongly dependent on the oxide type. In case of brown oxide, hackle-type failure was observed and failure path lay near the EMC/CuO interface with a little inclining to CuO at all case. On the other hand, in case of black oxide, quite different failure path was observed with respect to the distance from the tip of pre-crack and phase angle. Different failures occurred with oxide type is presumed to be due to the difference in microstructure of the oxides.

• 생약학회지
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• 제30권2호
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• pp.173-176
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• 1999

Bioassay-guided fractionation of a $H_2O$ extract of the roots of Gentiana scabra has furnished 5-(hydroxymethyl)-2-furfural (1) as an inhibitory compound for nitric oxide (NO) production in murine macrophage RAW 264.7 cells stimulated with $interferon-{\gamma}$ plus lipopolysaccharide. Compound 1 showed the moderate inhibition of NO production with $IC_{50}$ value of $803\;{\mu}M$.