• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.814-821
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• 2000

In order to investigate the possible use of omija extract as natural preservatives for nabak kimchi omija extract was tested for antioxidation and electron-donating ability and further more antimicrobial activites against lactic acid bacteria of nabak kimchi. The concentration of the test sample used were 0.5, 1.0, 1.5, 2.0%. Antioxidative activity measured the TBA value, when omija extract concentration % is higher the antioxidation effect were more evident with the increased omija extract concentrations, and showed a high electron donating activity more than 1.0%. As the result of isolated lactic acid bacteria from nabak kimchi the primary separation tool 117 strains, of these 4 strains which had excellent growth and a strong acid formation capability was selected the second time and Lactobacillus brevis, Lactococcus faecalis, Leuconostoc mesenteriodes, Lactobacillus palantarum were identified. After measuring the antimicrobial activity of the four lactid acid bacteris, except Lactobacillus brevis the other three bacteria showed strong antimicrobial activities. The results suggest the possible use of the omija extract as natural preservative for nabak kimchi.

• Journal of Nutrition and Health
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• v.36 no.2
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• pp.117-124
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• 2003

This study was designed to test the effect of Korean traditional tea materials on oxygen-free radical metabolism in lead (Pb) -administered rats. Male rats were divided into normal, Pb-control (Pb-Con) and Pb-water extract of green tea (Camellia sinensis; GT) , persimmon leaf (Diospyros kaki; PL) , safflower seed (Carhamus tinctorius: SS) , Du-Zhong (Eucommia ulmoides; EU) groups, respectively. Pb intoxication was induced by administration of lead acetate (25 mg/kg. B.W., oral) weekly. The extract was administered based on 1.26 g of raw material/kg B.W./day for 4 weeks. When the GT, PL, SS and EU were supplemented to the Pb-administered rats, hepatic lipid peroxide levels were significantly lower compared to the Pb-Con group. Hepatic cytochrom P-450 content and aminopyrine N-demethylase activity was lower in the Pb-Con group than in the normal group, whereas xanthine oxidase activity was significantly elevated in Pb-administered rats. The water extract of GT, PL, SS and EU supplementation attenuated changes in enzyme activities generating reactive oxygen species in the liver. Hepatic superoxide dismutase, catalase and glucose 6-phosphate dehydrogenase activities were significantly higher in the Pb-Con group than in the normal group, while monoamine oxidase activity also tended to increase in the Pb-administered rats. However, glutathione peroxidase and glutathione S-transferase activities, and glutathione content significantly decreased through Pb intoxication. The supplementation of GT, PL, SS and EU induced alleviation changes of hepatic antioxidant enzyme activity.

• Food Science and Preservation
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• v.31 no.1
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• pp.161-172
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• 2024

This study investigated the anti-obesity effects of lactic acid bacteria ferments cultured in industrial medium with ethanol extract of ramie leaf (Boehmeria nivea L.). On the 4th day of fermentation, the maximum live cell counts were 8.75-8.85 log CFU/mL, pH was 3.74-3.79, and total acidity was 2.07-2.19%. The fermentation of lactic acid bacteria on the fourth day resulted in the amount of lactic acid reaching 1,676.03-1,910.12 mg%. The lipase inhibitory activities of Lactiplantibacillus plantarum (L. plantarum) JBLAB0101 (FRLPLA) and Lactobacillus rhamnosus GG (LGG, (FRLLGG)) ferments were 30.10%, and 25.63%, respectively, at a concentration of 0.5 mg/mL. The lipid accumulation, leptin production, PPAR-γ and SREBP-1c mRNA levels were decreased to 37.54%, 54.64%, 24.18%, and 31.32%, respectively, at 200 ㎍/mL concentration of FRLPLA. These results suggest that anti-obesity effect could be increased by lactic acid bacteria in industrial medium with extract of ramie leaf.

• Applied Biological Chemistry
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• v.35 no.2
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• pp.82-86
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• 1992

This research was carried out to investigate antimutagent effect of peach enzymatic browning reaction products(PEBRP) obtained by reacting each of polyphenol compounds with oxidase extracted from Korea-cultivated peach. In methods, rec-assay with B. subtilis strains $H17(rec^+)\;and\;M45(rec^-)$, and Ames test with S. typhimurium TA98 and TA100 were used. The spore rec-assay of PEBRP, pyrogallol, hydroxyhydroquinone, homocatechol and caffeic acid were not showed mutagenicity. In the effects of various metal ions$(Al^{3+},\;Cu^{2+},\;Fe^{2+},\;Mn^{2+},\;Ni^{2+},\;Pb^{2+},\;Zn^{2+})$ on the rec-assay, all PEBRP except caffeic acid was increased inhibition zone(5 mm) only with $Zn^{2+}$. In paticular, the Py-PEBRP was decreased the difference of inhibition zone of growth on MMC(mitomycin C). In results of Ames test, all PEBRP were not showed mutagenicity on S. typhimurium TA98 and TA100; however, Ca-PEBRP and Hca-PEBRP were suppressed mutagenic effects on Trp-P-1 and B(a)P in the presence of S-9Mix.

• Journal of Conservation Science
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• v.29 no.4
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• pp.297-309
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• 2013

Iron objects become corroded at fast speed from the moment when they are excavated, so it is needed to control corrosion through processes of conservation treatment. However, re-corrosion mostly takes place in excavate iron objects, although they have already gone through the process of conservation treatment, and it is more difficult to carry out the second conservation treatment of re-corroded excavated iron objects than the first conservation treatment, and it requires a longer period of time to treat them as well. In this study, aims to discover factors of re-corrosion by scientifically analyzing corrosion products generated during the process of storage after the process of conservation treatment. The finished on conservation treatment of the iron artifacts, which were unearthed from three ancient site in Gyeongju by using the same conservation method between 2002 and 2009, re-corrosion condition observed on the packaging-iron artifacts. Focused on 9 target forged iron artifacts among them, this study analyzed the physical changes by mass measurement, naked-eye and microscopic observations and the chemical changes by SEM-EDS, XRD, IC and ICP analysis. The results show that the yellowish brown corrosion products formed on the facing surface of part dropped from the artifacts had different associated forms but acicular shape. In addition, the acicular shape became clearer as the color changed from red to yellowish brown. According to the process when the conservation treatment was completed, the mass of the artifacts increased in proportion to the corrosion products and the chloride ion ($Cl^-$) concentration had a tendency to increase relatively. ${\beta}$-FeOOH (akaganeite) was confirmed in the XRD analysis for the corrosion products of all the collected samples. As a result of ICP analysis, $Na^+$ and $Ca^{2+}$ components were confirmed.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.658-664
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• 2006

$\rho$, $\alpha$-dimethyl benzyl alcohol was resolved by the biphasic dynamic kinetic resolution (DKR). Acidic zeolite was used as a racemization catalyst while immobilized enzyme was employed for kinetic resolution. The effects of the process variables including nature of acyl donor, reaction temperature, substrate concentration, ratio of the two catalysts and stirring rate on the conversion and enantiomeric purity of the product were investigated. In DKR of $\rho$, $\alpha$-dimethyl benzyl alcohol, the product of 99% ee was obtained with a maximum yield of 88%. The high performance of the catalyst system was maintained in the condition of higher TON and under repeated use.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.166-169
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• 2002

본 연구는 콘크리트 배합시 염분의 함량이 구조물의 부식에 미치는 영향을 조사하기 위하여 수행되었다. 콘크리트는 물 : 포틀랜트 cemente : 자갈 : 모래의 비율을 1 : 1.78 : 5.35 : 4.73의 비율로 하여 배합하였으며 염분의 함량은 0-3.5wt%의 범위에서 철근의 부식을 연구하였다. 부식특성을 연구하기 위하여 부식전위를 2년간 측정하였으며 이를 콘크리트 파괴 후의 철근의 외관 부식도와 비교하였다. 옥내와 옥외에 두었을 때 부식속도의 차이는 없었으며 염분의 함량이 증가함에 따라 활성이 큰 전위값이 측정되었다. 전위값이 낮은 시편은 부동태 피막이 파괴되어 부식이 진행하고 있었으며, 전위값이 높은 시편에서는 부식생성물이 관찰되지 않았다. 본 실험의 결과로 보강용 강재의 부식손상 정도를 자연전위 측정방법을 통하여 콘크리트내 보강용 철근의 부식거동 및 부식속도에 대한 비괴적인 전기화학적 기술로서 구조물의 손상여부를 확인할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.286-286
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• 2011

현재의 NEDO (New Energy and industrial technology Development Organization) style Si 정련은 두 단계로 구분되어 있다. 고출력 집속 전자빔을 이용한 금속 실리콘의 1차 용융과 대기압 근처의 플라즈마 아크 용해를 이용해서 B, P를 약간의 반응성 가스를 첨가 하여 제거하는 방법이다. 그러나 저가형 실리콘을 생산하려는 취지와 달리 두 가지의 고가 장비가 필요하다. E-beam melting 장치에서도 반응성이 높은 라디칼을 생성할 수 있다면 하나의 장비에서 두 가지의 정련 작업을 진행시킬 수 있다. 본 연구에서는 고진공에서(< 10-4 Torr) 동작하는 E-beam의 성능에 전혀 영향을 주지 않으면서 플라즈마를 용이하게 생성 시킬 수 있는 방법을 개발하고 이를 적용하여 실제 금속 순도 실리콘 내에 존재하는 B, P가 제거되는지 확인하는 것을 연구 내용으로 한다. 본 연구는 MG (Metal Grade) - Si 을 플라즈마 보조 전자빔 정련을 이용하여 정련한 Si 의 불순물 함량의 개선 효과를 조사하는 것이다. MG-Si 의 정련 방법 중에서 고출력 집속 전자빔을 이용하여 휘발성 오염물질을 제거 후, 플라즈마 아크 용해를 이용해서 B 를 제거하는 방법을 접목시켰다. MG-Si 에 DC power 와 전자빔을 집속시켜서 정련을 하면 챔버 내의 잔류 수증기가 플라즈마에 의해 분해되어 O를 생성하고, B와 반응을 하여 BO 형태로 제거가 된다. 방전 전압 700 V 와 전자빔 가속 전압이 4.5 kV, 방출 전류는 11 A, 진공 챔버 내의 압력은 $7.2{\times}10^{-4}$ Torr에서 정련을 진행하여 B를 제거했다.

• Korean Journal of Materials Research
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• v.5 no.3
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• pp.333-344
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• 1995

Cu를 함유한 2종의 저합금 고장력강(HSLA-A, HSLA-B)\ulcorner 기계적 성질에 미치는 시효처리의 영향을 조사하였다. 탄소량이 적음에도 불구하고 Cu첨가로 석출물을 생성시킴으로서 2합금 모두 $650^{\circ}C$에서 시효한 경우 양호한 강도(HSLA-A:Y.S 703Mpa, E.L 22.6% HSLA-B:Y.S 810 Mpa, E.L 23.8%)와 인성(HSLA-A:271.4J, HSLA-B:197.5J at -5$0^{\circ}C$)의 조합을 나타내었다. 50$0^{\circ}C$에서 시효할 때 가장 높은 항복 강도를 나타내나 인성은 아주 낮은 값을 나타내었다. 50$0^{\circ}C$이상 시효 온도가 증가하면 강도는 감소하고 인성은 증가하였다. HSLA-B강의 강도가 HSLA-A 강보다 높은데, \ulcorner칭 상태에서의 강도 차이는 경화능을 증가시키는 원소인 Ni, Mn, Mo, Cu의 첨가량 차이에 의한 기지 조직의 차이에 의한 것이며, 시효한 상태에서의 강도 차이는 기지 조직과 석출 강화에 기여하는 Cu량의 차이에 의한 것으로 판단된다. 시효 경화 곡선에서 $700^{\circ}C$에서의 경도 증가는 오스테나이트-페라이트 2상 영역으로부터 냉각시 생성된 “M-A constituents”에 의한 것이다. HSLA-A강과 HSLA-B강의 충격 천이 온도는 각각 -1$25^{\circ}C$와 -145$^{\circ}C$이었다.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.1-5
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• 2016

For obtain fermentable sugar, we conducted acid hydrolysis with lignocellulosic biomass without enzyme. The lignocellulosic biomass used pinus rigida and Palm residues (EFB; empty fruit bunches). In the acid hydrolysis, we consider the hydrolysis condition to reduce a denatured sugar. So this study was conducted 2-step acid hydrolysis. First-step hydrolysis used high concentration (72 wt%) sulfuric acid at $80^{\circ}C$. At the condition, we obtained 11.49 wt%, 32 wt% glucose conversion for pinus rigida and EFB. After the step, the liquor was dilute until 9~15 wt% acid concentration and conducted second hydrolysis at $50{\sim}120^{\circ}C$. In the second hydrolysis, we obtained maximum glucose conversion (pinus rigida 86.8 wt% (39 g/L) and EFB 95.3 wt% (32.4 g/L)) at 9 wt% acid concentration and $120^{\circ}C$ for 80 min. All samples through the process are analyzed on the basis of mass balance.