• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.225-237
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• 2018

This study was conducted to compare nutritional analysis and neuroprotective effect of 5 cultivars of Diospyros kaki (Dungsi, Godongsi, Gojongsi, Gabjubaekmok, and Bansi). In nutritional analysis, three free sugars: sucrose, glucose, and fructose, and six fatty acids: tartaric acid, hexadecanoic acid, palmitic acid, oleic acid, octadecenamide, and octadecane, were detected. Potassium and phosphorus levels were the highest in inorganic component analysis, and glutamic acid and aspartic acid were the highest contents in amino acid analysis. Vitamin C was detected in all cultivars. Total phenolic content was the highest in Dungsi. Antioxidant activities such as ABTS (3-ethylbenzothiazoline-6-sulfonic acid), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activities, FRAP (ferric reducing/antioxidant power), and MDA (malondialdehyde) inhibitory effect were the highest in Gabjubaekmok. Acetylcholinesterase inhibitory activity, cell viability, intracellular reactive oxygen species (ROS) accumulation, and lactate dehydrogenase (LDH) release were measured to confirm the neuroprotective effect in MC-IXC cells. Gabjubaekmok showed significant acetylcholinesterase (AChE) inhibition and neuroprotection.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.6.1-6.1
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• 2010

원자층 증착 기술 (Atomic Layer Deposition)은 기판 표면에서 한 원자층의 화학적 흡착 및 탈착을 이용한 nano-scale 박막 증착 기술이기 때문에, 표면 반응제어가 우수하며 박막의 물리적 성질의 재현성이 우수하고, 대면적에서도 균일한 두께의 박막 형성이 가능하며 우수한 계단 도포성을 확보 할 수 있다. 최근 ALD에 의한 박막증착 방법 중 플라즈마를 이용한 ALD 증착 방법에 대한 다양한 연구가 진행되고 있다. 플라즈마는 반응성이 좋은 이온과 라디컬을 생성하여 소스간 반응성을 좋게 하여, 소스 선택의 폭을 넓어지게 하고, 박막의 성질을 좋게 하며, 생산성을 높일 수 있는 장점이 있다. 그러나 플라즈마를 사용함으로써 플라즈마 내에 이온들이 가속되서 박막 증착 중에 기판 및 박막에 손상을 입혀 박막 특성을 열화 시킬 가능성이 있다. 따라서 플라즈마 발생 영역을 기판으로부터 멀리 떨어뜨린 원거리 플라즈마 원자층 공정이 개발 되었다. 이 기술은 플라즈마에서 생성된 ion이 기판이나 박막에 닫기 전에 전자와 재결합 되거나 공정 chamber에서 소멸하여 그 영향을 최소하고 반응성이 좋은 라디칼과의 반응만을 유도하여 향상된 막질을 얻을 수 있도록 하였다. 따라서 이 원거리 플라즈마 원자층 증착기술은 나노 테크놀러지 소자 개발하기 위한 나노 박막 기술에 있어서 그 활용이 점점 확대될 것이다. 그 적용으로써 리모트 플라즈마 원자층 증착 방법을 이용한 고유전 물질 개발이 있다. 반도체 소자의 고집적화 및 고속화가 요구됨에 따라 집적회로의 크기를 혁신적으로 축소하여 스위칭 속도(switching speed)를 증가시키고, 전력손실 (power dissipation)을 줄이려는 시도가 이루어지고 있다. 그 중 하나로 고유전율 절연막은 트렌지스터 소자의 스케일링 과정에 수반하여 커지는 게이트 누설 전류를 억제하기 위한 목적으로 도입되었다. 유전율이 크면 동일한 capacitance를 내는데 필요한 물리적인 두께를 늘릴 수 있어 전자의 tunneling을 억제할 수 있고 전력손실을 줄일 수 있기 때문이다. 이와 같은 고유전율 물질이 게이트 산화막으로 사용되기 위해서 높은 유전상수 열역학적 안정성, 낮은 계면 전하밀도, 낮은 EOT, 전극 물질과의 양립성 등의 특성이 요구되는데, 이에 따라 많은 유전물질에 대한 연구가 진행되었다. 기존 gata oxide를 대체하기 위한 가장 유력한 후보 재료로 주목 받고 있는 high-k 물질들로는 Al2O3, HfO2, ZrO2, La2O3 등이 있다. 본 발표에서는 ALD의 종류에 따른 기술을 소개하고 그 응용으로 고유전율 물질 개발 연구 (고유전율 산화물 박막의 증착, 고유전율 산화물의 열적 안정성 평가, Flatband 매카니즘 규명, 전기적 물리적 특성 분석)에 대해서 발표 하고자 한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.122-122
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• 2014

수중방전을 환경분야에 적용하기 위한 플라즈마 부상법이 개발되었다. 플라즈마 부상법은 물 속에서 발생시킨 플라즈마가 가지고 있는 주요특성 중 물리적 특징인 쇼크웨이브, UV조사, 버블생성 등과 화학적 특징인 OH라디칼 및 염소산화물 생성 등을 이용하여 물 속에 존재하는 용존성 및 입자성 물질을 부상분리 기법으로 제거하는 공법이다. 유기물을 제거하는 기작으로는 침전, 여과, 분해 등이 있고, 이를 구현하기 위한 공정으로 중력침강법, 부상분리법, 멤브레인법, 미생물법 등이 있다. 이 중에서 가압공기부상법은 침강법에 비해 부지면적을 적게 소모하고 처리시간이 50% 이상 감소되는 특징이 있다. 가압공기부상법은 물 속에 공기를 과포화시킨 후 노즐을 통해 재분사할 때 발생하는 압력차에 의해 미세기포가 발생함을 이용하여 유기물을 분리하는 공법이다. 그러나, 가압용 장비 및 반송수가 필요하고, 미생물분리는 불가능한 단점이 있다. 이에 본 연구에서는 미생물살균과 유기물 분리가 동시에 일어나는 플라즈마를 이용한 부상분리기법을 개발하였다. 본 연구에서는 난분해성 용존유기물인 휴믹산 100 mg/L의 플라즈마 공기부상법에 의한 제거능을 확인하였다. 용존성 휴믹산을 입자성 물질로 전환하여 플록을 형성시키고자 알루미늄설페이트(Al2(SO4) $3{\cdot}18H2O$)를 100 mg/L 주입하였고, 침출수와 같이 염도가 높은 물을 모사하고자 35 g/L의 염화나트륨을 첨가한 상태에서 방전을 실시하였다. 방전에 사용된 전원은 EESYS사에서 제작한 펄스형 고전압 전원장치를 사용하였고 최대 15 kW의 출력 중 6 kW의 전력을 인가하였다. 전극 한 개는 2 mm 텅스텐봉을 세라믹튜브로 감싼 구조로 총 사용전극은 28개이다. 전극 한 개당 대략 200 Watt의 전력이 소모되며 이 때 최대의 버블이 생성됨을 확인하였다. 전극 1개에서 생성되는 버블의 부피는 14 mL/min 로 측정되었다. 버블의 크기는 평균 70 um이고 가압공기부상법에서 최적공기크기로 제시하고 있는 40~80 um 의 버블은 약 80% 가량 생성된다. 본 연구에서 사용된 반응시스템에서의 물의 높이는 약 500 mm 이고 전체 40 L의 수조가 3개의 벽으로 분리되어 4개의 수조로 분리되었다. 각 수조는 하부에 7개의 전극을 포함하고 있다. 플라즈마 발생시 생성되는 기포는 약 1분 방전 후에 포화농도에 도달하며 방전종료 후 약 4분간 수체 내에 남아있게 된다. 이를 공정에 적용하여 1분 방전 및 4분 휴지의 순서로 플라즈마를 인가하였다. 휴믹산 용액의 유량을 2 lpm 으로 운전하였을 때 최종 처리율은 94% 이고 이때의 대장균 살균능은 99%이다.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.2
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• pp.5-13
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• 2024

This study was conducted to investigate the effect of salinity stress on the antioxidant and anti-inflammatory activities of Crepidiastrum sonchifolium. The plant was treated with NaCl at concentrations of 0, 50, 100, and 200mM for 6 weeks. After treatment, the whole plant was collected, and 70% ethanol extracts were prepared. The DPPH radical scavenging activity was highest in the order of NaCl treatment concentrations of 0, 100, and 50mM, while the 200mM treatment group showed the lowest radical scavenging. The total phenol and total flavonoid contents showed very similar results to the antioxidant activity depending on the NaCl concentration, confirming that the phenolic compounds of the plant can contribute to the antioxidant capacity against salinity stress. In addition, the investigation of the effect of NaCl-treated C. sonchifolium extract on the inhibition of NO production in the LPS-stimulated mouse macrophage cell line (Raw 264.7) revealed that NO production significantly decreased in the 1,000㎍/mL treatment group across all NaCl concentration groups. But, the high concentration (1,000㎍/mL) treatment of the 100mM and 200mM NaCl treatment groups was found to have a negative effect on cell survival. These results suggest that radical scavenging activity is highest in healthy plants and that they produce antioxidants to respond to NaCl salinity stress up to 100mM. However, a high NaCl concentration of 200mM has a negative effect on the physiological activity of the plants. Compared with the results of the previously reported growth index, it is thought that the growth and physiological activity of plants can be positively affected in an NaCl treatment environment of 50mM or less.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.190-195
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• 1999

The thermal pyrolysis of chlorodifluoromethane (R22) for producting tetrafluoroethylene (TFE) has been studied using the tubular reactor designed by the authors. The reaction temperature over $600{\sim}850^{\circ}C$, residence time over 0.005~0.6 sec, and steam/R22 ratio 3 to 30 were varied through experiments to analyze the effect of these variables on the conversion of R22 and selectivity for TFE. We have provided the guidelines for the optimal operation and design for the pyrolysis reactor. With increasing the dilution ratio, not only the conversion of R22 but also the selectivity for TFE increase. The optimum range of reaction temperature was $700{\sim}750^{\circ}C$ and the residence time 0.07~0.1 sec. In the kinetic study, first order rate equation was fitted well with the experimental data. This indicates that the main reaction step is a $CF_2$ generation from R22 pyrolysis. The range of activation energy for the rate constant was obtained 44.7~48 kcal/mol.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.486-492
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• 2009

Wet oxidations (WO) of quinoline in aqueous solution were carried out at $225^{\circ}C$ and $250^{\circ}C$. In the WO at $250^{\circ}C$, quinoline was degraded completely within 30 min and the reduction in total organic carbon (TOC) of 63% was achieved during 120 min. However, the rate of the reduction in TOC was only 13% within 240 min during the WO at $225^{\circ}C$. Nicotinic and acetic acid were found to be main intermediates formed during the oxidation of quinoline. With the addition of the homogeneous catalyst $CuSO_4$ or more easily oxidizable phenol, WOs of quinoline were also carried out under moderate conditions at $200^{\circ}C$. The catalytic WO with $CuSO_4$ of 0.20 g/L showed the destruction rates of quinoline and TOC comparable to those in the WO at $250^{\circ}C$. The WOs of quinoline-phenol mixture exhibited induction periods to degrade quinoline and phenol during which free radicals were produced to initiate WOs. With increasing initial concentrations of phenol at a given initial concentration of quinoline, the induction periods in the destructions of quinoline and phenol became shorter and the reduction in TOC increased from 60% to 75% during 180 min of the WOs. The reduction rate of an induction period decreased as increasing the initial concentration ratio of phenol to quinoline. On the other hand, phenol degradation in the WOs of quinoline-phenol mixtures required a longer induction period and proceeded slower compared to the case of the WO of phenol.

• Food Science and Preservation
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• v.24 no.7
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• pp.1025-1033
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• 2017

In this study, Ledum palustre L. was extracted by 4 different methods (LPW, hot water extraction; LPA, autoclave extraction; LPU, ultrasonification extraction; LPE, 70% ethanol extraction) and LPE was fractionated by using polarity difference of each solvent and used as 4 samples (LPE/H, the n-hexane layer; LPE/E, the EtOAc layer; LPE/B, the n-BuOH layer; LPE/W, the $H_2O$ layer). Antioxidant activities of Ledum palustre L. extracts were measured by DPPH and ABTS. As a result, the DPPH and ABTS radical scavenging showed high activities with LPE (82.3%, 99.8%) and LPE/E (91.8%, 99.6%) at the concentration of $1,000{\mu}g/mL$. The anti-inflammatory activities of LPE and LPE/E were measured by the inhibitory activity against NO, $PGE_2$, TNF-${\alpha}$, IL-$1{\beta}$ and IL-6 production on LPS-stimulated Raw 264.7 macrophages. As a result of MTT assay, cell viabilities of LPE and LPE/E were more than 90% at $25{\mu}g/mL$. NO and $PGE_2$ productions were inhibited by LPE (NO: 50%, $PGE_2$: 70%) and LPE/E (NO: 57%, $PGE_2$: 73%) at the concentration of $25{\mu}g/mL$. The inhibition activities against TNF-${\alpha}$, IL-$1{\beta}$, IL-6 production were 24%, 47% and 40% at the concentration of $25{\mu}g/mL$ of LPE. In particular, LPE/E showed 51%, 57% and 62% inhibition activities at the same concentration, respectively. From the above results, it can be concluded that $1,000{\mu}g/mL$ of LPE and LPE/E have the high antioxidant activities similar with Vitamin C, and $25{\mu}g/mL$, the low concetration of LPE and LPE/E have excellent anti-inflammatory activities. Therefore, if more research about anti-aging, whitening and antimicrobial activity of Ledum palustre L. extracts is carried out in the future, it will be possible to use them as effective materials for the prevention and treatment of inflammatory diseases and in the areas of functional foods and cosmetics.

• Journal of Mushroom
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• v.18 no.1
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• pp.45-52
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• 2020

Termitomyces albuminosus has been recognized to have the best mushrooms in China, in terms of taste and aroma. The efficacy of these mushrooms has been recorded in the botanical list. However, research on the development of their artificial culture methods is necessary. In this study, we prepared an organic solvent extract and a hot water extract to understand the development of compounds and functional foods with antioxidant and anti-inflammatory activities. The IC₅₀ value of DPPH radical scavenging activity of the hot water extract (TA4) was 1.5 mg/mL and the IC₅₀ value of the MeOH fraction (TA2) was 1.93 mg/mL. The anti-inflammatory activity was investigated by the inhibition of NO production. EtOAc fraction (TA1) is a crude extract, but 79% of NO production was inhibited at 100 ㎍/mL. NO was not produced at 200 ㎍/mL. TA1-5-6, from TA1 inhibited NO production by 15% as compared to the positive control at 15 ㎍/mL, and completely inhibited NO production at 30 ㎍/mL. No cytotoxicity was observed at 50 ㎍/mL. TA2-1-5 from the MeOH fraction (TA2) inhibited more than 75% of NO production at 30 ㎍/mL; cytotoxicity was very low even at 50 ㎍/mL. In conclusion, by selective solvent selection, it was possible to manufacture an extract with no cytotoxicity and excellent biological activities. Furthermore, the extracts showed potential for developing various functional foods and drugs.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.576-583
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• 2019

The effect of aeration process in causing changes in the prosapogenin content and the antioxidant activity of red ginseng powder extracts was investigated. With respect to the color change of the extracts, the L-value and b-value decreased significantly with the lapse of extraction time both with and without the aeration process. The a-value increased with the lapse of the extraction time in the non-aeration process but decreased in the aeration process. This result suggests that when the aeration process was performed, the lightness, yellowness, and redness decreased with the lapse of the extraction time, resulting in a darker color. The total polyphenolic and total flavonoid contents were the highest at 0.84 and 0.96 mg Gallic Acid Equivalent (GAE)/mL, 21.77 and 21.93 mg GAE/mL at 24 h and 36 h, respectively for the aerated red ginseng powder extracts. The DPPH, ABTS, H₂O₂ scavenging activity, and reducing power were measured to confirm the antioxidant effects of red ginseng powder extracts after the aeration process. Thus, the antioxidant activity was increased in the aerated red ginseng powder extracts. In addition, when comparing the contents of Rb1, Rg1, and Rg3, the content of Rg3 was significantly different, and it was confirmed that a large amount was produced in the aerated red ginseng extracts. These results indicate that the red ginseng extracts subjected to the aeration process are superior than the ones processed by the non-aeration process.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.569-574
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• 2007

This study was performed to investigate the biological activities of roasted (RE) and non-roasted (NRE) hot water extract samples from Euonymus alatus leaf by measuring DPPH radical scavenging, total polyphenol content, hydroxyl radical scavenging, superoxide dismutase (SOD)-like activity, anti-inflammatory activity, and inhibitory effects on ${\alpha}-amylase$ and ${\alpha}-glucosidase$ in vitro. The $IC_{50}$ values fur DPPH free radical scavenging activity of the NRE and RE hot water extracts were $19.1{\mu}g/mL$ and $21.9{\mu}g/mL$, respectively, and their total polyphenol contents were estimated as 9.6 mg/g for NRE and 10.6 mg/g for RE. Both NRE and RE scavenged the hydroxyl radical in a concentration-dependent manner, but their activities were lower than that of BHA. It was also shown that SOD-like activity was dependent on NRE and RE concentration, and the SOD-like activity of NRE was slightly higher than that of RE. The highest SOD-like activity obtained from NRE was 20% at a concentration of 3 mg/mL. Neither NRE nor RE seemed to have an effect on ${\alpha}-amylase$ and ${\alpha}-glucosidase$ inhibition. Finally, the hot water extracts of NRE and RE significantly decreased the concentration of LPS-induced NO in RAW 264.7 cells, indicating anti-inflammatory activity.