• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.3
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• pp.117-121
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• 2003

Nickel(Ni) powders were prepared from the mixture of nickel chloride and magnesium stearate by a hydrogen reduction process, and the effect of reaction temperature and the addition of magnesium stearate on the chracteristics of the powders were investigated. The effect of size reduction of nickel particles was observed in the presence of magnesium stearate owing to the inhibition of excess growth of paricles. The size reduction and the degree of agglomeration of the particles affected by the amounts of liqiud phase, which related to the increase of magnesium stearate.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.63-70
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• 2001

Sodium persulfate, prestogen W, prestogen EB, citric acid 및 thiourea의 첨가에 따른 $H_2O_2$ 표백 효과가 연구되었다. Sodium persulfate(1%), Prestogen EB(15.0%)를 $H_2O_2$ 활성제로 첨가하여 표백할 경우 기존 $H_2O_2$ 표백(86.0% ISO)보다 표백 펄프의 백색도가 2-3% ISO 더 증가하였다. $H_2O_2$ 표백 후 thiourea를 첨가하여 표백하는 산화-환원 연속표백(87.9% ISO)에서도 $H_2O_2$ 표백 후 FAS로 2단 표백(88.3% ISO)을 한 경우와 비슷한 백색도를 나타내었다. 한편 표백 펄프의 인장지수, 파열지수 그리고 인열지수는 기존 표백 또는 Prestogen EB를 첨가할 경우 높고 sodium persulfate 첨가에서 가장 낮았다. 산화-환원 연속 표백된 펄프의 강도도 기존 $H_2O_2$ 표백보다 미세하게 낮았다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.92-93
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• 2014

주석 도금시 발생하는 주석 폐 도금 슬러지로부터 주석을 회수하기 위해 염산 직접 침출방법과 환원 열처리($700^{\circ}C{\sim}1100^{\circ}C$)후 염산 침출방식을 고찰하였다. 폐 슬러지의 염산 직접 침출시 주석의 침출율은 40% 이하였다. 폐 슬러지를 수소분위기하에서 $700^{\circ}C$, $800^{\circ}C$, $900^{\circ}C$, $1100^{\circ}C$로 열처리한 후에 염산을 이용하여 침출시에는 환원된 주석의 침출율이 97% 이상이었고, 온도가 $800^{\circ}C$일 때 침출율이 98.2 %로 가장 효과가 좋았다.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.35-41
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• 2011

Temperature programmed reduction experiments for Fe- and Co-oxides were performed and weight losses were carefully measured to calculate the extent of reduction. Addition of nickel and palladium affected the reduction by lowering the DTG peak temperature. Reduction experiments for the oxides on alumina were also studied and the effect of nickel and palladium addition was confirmed. And that was explained by means of increased adsorption of hydrogen and increased diffusion ability of the surface hydrogen.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1045-1051
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• 1997

Three kinds of model melanoidins adjusted to have the same brown color intensity were made from glucose-glycine, glucose-lysine, xylose-arginine and their antioxidative properties were determined. The antioxidative activities of these model melanoidins in linoleic acid emulsion system were determined by ferric thiocyanate method, conjugated diene contents, peroxide value and electron donating ability by DPPH. Xylose-arginine melanoidin showed the strongest antioxidative activity and electron donating ability. The antioxidative effect of melanoidin could be reliably predicted by determining peroxide value and DPPH method. Each melanoidin was separated on Sephadex G-50 column, and brown color intensity, reducing power, ninhydrin positive reaction and antioxidative activity of each fraction were determined. The antioxidative activities of melanoidin fractions showed strong correlation with their brown color intensity and especially to their reducing power. In spite of same brown color intensity, there is no big differences between these model melanoidins, thus xylose-arginine showing strongest antioxidative activity followed by glucose-lysine and glucose-glycine melanoidin. Xylose-arginine melanoidin also showed the strongest electron donating activity and broad range of reducing power when fractionated on Sephadex G-50, which was different tendency from the other model melanoidin.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.285-294
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• 1994

Some supported gold catalysts were prepared by impregnation and coprecipitation methods. Effect of gold addition and active sloe formation were studied by investigating particle sizes of gold, amounts of oxygen adsorbed, adsorption properties of CO and NO, and reduction and oxidation properties, etc.. The gold particles of the catalyst by impregnation were irregular and very large as 30~100 nm, but those by coprecipitation were uniform and ultra-fine as about 4 nm. On $Au/Al_2O_3$ catalyst, the addition of gold to inactive $Al_2O_3$ caused the decomposition of $N_2O$, and CO was not irreversibly adsorbed while $O_2$ was atomically and irreversibly adsorbed. The adsorption sites of oxygen were attributed to the active sites which were restricted to the circumference of hemispherical gold particle-support interface rather than all atoms on the surface of gold particle. Also, CO was reversibly and irreversibly adsorbed on $Al_2O_3$ at low temperature, and the addition of gold weakened both reversible and irreversible adsorptions. The affinity for CO on $Au/Co_3O_4$ catalyst decreased conspicuously compared to $Co_3O_4$. The effect of gold addition did not appear in reduction step but did remarkably in reoxidation step; the added gold promoted the reoxidation of the reduced cobalt atoms.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.164-170
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• 2010

In organic agriculture, cover crops are used for weed control. Cover crops inhibited weed germination or growth by allelopathy or shading effects. In this study, we used rye as cover crop to control weed in organic soybean field. The main treatment was rye using method such as living mulch, incorporating and mowing. Sub-treatment was rye planting density and soybean planting density. One month after soybean sowing, weed emergency and growth had been highly suppressed by rye in all treatments. Living mulch treatment was the best effective way to control the weed about 92%, and mowing treatment was the second about 75% compare to control. The weed control efficiency between rye planting densities was similar during one month. Soybean planting density treatment was same result as rye planting density. As a result of this experiment, we recommend rye as living mulch in one row planting.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.254-260
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• 2015

The effect of the extraction solvent on the physiological properties of the peel of the Korean pear (Pyrus pyrifolia cv. Niitaka) was evaluated. The total phenol content was highest in the 80%(wt) methanol extract, whereas flavonoid content was highest in the 80% ethanol extract. The antioxidant activities of the extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities, and their reducing power. The water and 80% methanol extracts of the pear peel had highest DPPH and ABTS radical scavenging activities, and reducing power, respectively. The inhibition of ${\alpha}$-glucosidase was highest in the 80% methanol extract, and alcohol dehydrogenase activity was highest in the water extract. All three extracts had similar antimicrobial activity. Because water, 80% ethanol, and 80% methanol extracts exhibited high activities in different assays of physiological properties, each solvent could be used for specific purposes.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.117.2-118
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• 2003

절임식품은 우리 고유의 먹거리이지만 체계적인 연구가 부족하여 품질표준화가 이루어지지 않고 있어 우리의 전통식품을 세계적인 식품으로 개발하기 위해서는 전통식품을 과학화하고 현대화할 수 있는 연구가 필요하다. 새로운 된장절임 가공법을 개발하고자 blanching, salting, drying 등의 전 처리를 행한 후 된장 절임기간에 따른 새송이 버섯의 수분함량, 염도, 색상, 조직특성, 관능특성 등의 변화를 조사하였다. 된장절임기간에 따른 새송이 버섯의 수분함량 변화는 숙성시간이 경과함에 따라 감소하였으며 염도는 시간이 지남에 따라 증가하는 경향을 보였으나 무처구를 제외하고는 숙성 30일 이후부터는 변화가 거의 없었다. 숙성기간에 따른 색상의 변화를 보면 블랜칭이 매우 효과적으로 변색을 방지하였다. 숙성 30일부터는 모든 처리구에서 강도가 저하하는 경향을 보였으며 관능평가 결과 숙성 40일째에 맛과 조직감 그리고 기호도 등 모든 항목에서 B(B)와 E(BSD) 처리구가 높은 점수를 받아 관능적 품질 특성이 가장 우수하였다. 이상의 결과로 볼 때 전처리공정에 있어서는 7$0^{\circ}C$에서 10분간 블랜칭처리한 B(B)처리구가 가장 우수하였으나 된장 절임후 숙성기간이 경과함에 따라서는 7$0^{\circ}C$에서 10분간 블랜칭처리후 5% 염용액에서 72시간 절임한 후 4$0^{\circ}C$에서 30분간 탈염하고, 다시 5$0^{\circ}C$의 온도에서 3시간 건조시킨 E(BSD)처리구도 우수한 품질을 유지할 수 있어 새송이 버섯을 이용한 장류절임가공법으로 활용이 가능함을 확인하였다.d, citric acid 그리고 shikimic acid가 검출되었고 수확시기에 3품종에서 모두 malic acid 함량이 가장 높았고 malic acid와 citric acid의 함량이 풍수와 신고에서는 약 0.3%, 추황은 0.4% 이상으로 나타났다. 또한 3품종 모두에서 총산과 같은 추세로 성숙기의 유기산의 함량이 생장초기의 함량보다 많이 감소되었음을 알 수 있었다. 배의 가용성 고형물은 전체적으로 과실의 성장이 진행됨에 따라 증가하는 추세를 나타내었다. 풍수와 신고 과피의 총당과 환원당은 거의 같은 추세로 증가하였고 성숙이 가까워지면서 환원당이 감소하였다. 배 과육의 총당과 환원당 또한 거의 같은 추세로 증가를 하다가 수확 전 20일 혹은 30일부터 총당의 함량은 계속 증가하지만 환원당의 함량은 큰 변화가 없는 것으로 나타났다. 배 과실의 전반 성장과정에 있어서 전분함량은 감소하였고 총탄수화물의 함량은 과육에서는 증가하나 과피에서는 반대로 감소하는 경향을 보였다. 풍수의 전분함량은 최고 2.19%에서 0.23%로 감소하였고 신고에서는 0.43%로 추황에서는 0.48%로 감소하였다. 배 유리당은 fructose, glucose, sorbitol, sucrose 둥 4종류의 당이 검출되었고 3품종 모두에서 생장과정 중 비환원당인 sucrose 함량은 계속 증가하였고 fructose, glucose, sorbitol의 함량(추황의 sorbitol을 제외)은 생장이 촉진됨에 따라 증가하다가 다시 점차적으로 감소하였다. 이러한 결과는 총당과 환원당의 측정결과와 일치한 것으로 나타났다. 결론적으로 배의 성장에 따라 산 함량은 감소하였고 당 함량은 증가하였다.luco-pyranosi

• Analytical Science and Technology
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• v.11 no.6
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• pp.460-468
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• 1998

Schiff base ligands such as $SOPDH_2$, $SNDH_2$, $EBNH_2$, and $PBNH_2$ and their Co(II) complexes such as [$Co(II)(SND)(H_2O)_2$], [$Co(II)(SOPD)(H_2O)_2$], [$Co(II)(EBN)(H_2O)$], and [$Co(II)(PBN)(H_2O)$] have been synthesized. The mole ratio of Shiff base ligand to cobalt(II) for the Co(II) complexes was found to be 1:1. Also these complexes have been configurated with hexa-coordination. Reduction of dioxygen was investigated by cyclic voltammetry at glassy carbon electrodes modified with Schiff base Co(II) complexes in 1 M KOH aqueous solution. At modified glassy carbon electrode with Schiff base Co(II) complexes, reduction peak current of oxygen was increased and peak potential was shifted to more positive direction compared to bare glassy carbon electrode. The electrokinetic parameters such as number of electron and exchange rate constant were calculated from the results of cyclic voltammogrms. The reduction of dioxygen at glassy carbon electrode has been $2e^-$ reaction pathway. Exchange rate constant at glassy carbon electrode modified with Co(II) complexes was increased 2~10 times compared to bare electrode.