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        검색결과 84

        21.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지역별 백리향 지상부 잎의 phenols 성분의 효과적인 추출을 알아보기 위해 추출용매를 달리하여 추출하고, GC-MS로 분석한 결과thymol과 carvacrol을 포함한 phenol함량이 methanol 추출 시 울릉도, 제주 중간산지, 경기도, 제주도 고산지, 강원도 종이 각각 92.21, 84.92, 77.43, 74.16, 73.51%로 추출되었으며, ethanol 추출 시 전체 추출 성분 중 강원도, 제주도 중간산종, 경기도, 울릉도, 제주고산종이 각각 93.64, 93.62, 90.74, 89.52, 72.65% 순으로 나타났다. Hexane을 용매로 추출하였을 때에는 강원도와 울릉도 서식의 백리향은 거의 100, 95.71%의 phenol만 추출되었다.
        4,000원
        22.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the total phenol contents, antioxidative activities and antibacterial activities of twenty species of entomopathogenic fungi. The total phenol content was highest in Aspergillus flavus (553.0±52.15 ㎍/g) and A. parasiticus (529.9±60.10 ㎍/g). On the other hand those in other strains were within the range of 26.6~121.9 ㎍/g. The antioxdative activity was shown in the most of strains and the highest DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging activity was observed in A. flavus (90.9±2.90%) and A. parasiticus (77.9±4.13%). This result indicated that the antioxidative activities were very correlated with the total phenol contents. The antibacterial activitiy was found in the every tested pathogenic bacteria. Especially, the antibacterial activity was strongest against Listeria monocytogenes and Escherchia coli.
        4,000원
        24.
        2009.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A mathematical model was written for simulating the removal of phenol from wastewater in enzyme-loaded membrane reactor (EMR). The numerical simulation program was developed so as to predict the degradation of phenol through an EMR. Numerical model proves to be effective in searching for optimal operating conditions and creating an optimal microenvironment for the biocatalyst in order to optimize productivity. In this study, several dimensionless parameters such as Thiele Modulus (Φ2, dimensionless Michaelis-Menten constant (ξ), Peclet number (Pe) were introduced to simplify their effects on system efficiency. In particular, the study of phenol conversion at different feed compositions shows that low phenol concentrations and high Thiele Modulus values lead to higher reactant degradation.
        4,200원
        26.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        식용꽃인 꽃베고니아(Begonia semperflorens ‘Superolympia White’), 토레니아(Torenia fournieri ‘Crown Pink’), 팬지(Viola tricolor ‘Solvetsunny Royal’) 및 펠라고니움(Pelargonium grandiflorum ‘Jessie Jarrett’) 추출물의 총페놀 함량, 전자공여능 및 세포독성에 미치 는 영향을 조사하였다. 에탄올 추출물의 총 페놀함량은 펠라고니움의 경우 531.57mg/100g으로 높게 나타났으 나 토레니아는 30.98mg/100g, 팬지는 14.62mg/100g, 꽃베고니아는 5.77mg/100g으로 낮게 나타났다. 전자공 여능은 꽃베고니아, 토레니아, 팬지의 열수 및 에탄올 추출물은 500g·mL-1에서는 모두 69.4% 이하를 나타 냈으나 펠라고니움의 열수 및 에탄올 추출물은 125g·mL-1에서도 각각 94% 내외를 나타내었다. 세포 생존율은 토레니아와 팬지의 열수 및 에탄올 추출물 처리구에서는 95% 이하를 나타내어 세포사가 일어난 것으로 추정되었다. 히스타민 억제효과는 펠라고니움 추출물의 경우 91% 이상을 나타냈으나 토레니아 추출 물은 51-66%, 팬지 추출물은 14-24%, 꽃베고니아 추 출물은 1~2%의 억제 효과만 나타났다.
        4,000원
        27.
        2006.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Activated carbon fiber could be prepared at 973 K by catalytic activation using potassium hydroxide. Phenol resin fiber (Kynol) was impregnated with potassium hydroxide ethanol solution, carbonized and activated at 973 K, resulting in activated carbon fibers with different porosities. The potassium hydroxide accelerated the activation of the fiber catalytically to form narrow micropore preferentially in carbon dioxide atmosphere. The narrow micropore volume of 0.3~0.4 cc/g, total pore volume of 0.3~0.8 cc/g, mean pore width of 0.5~0.7 nm was obtained in the range of 20~50% burnoff.
        4,000원
        28.
        2006.06 KCI 등재 구독 인증기관·개인회원 무료
        The objective of this study was to identify the variation of individual phenol content and antioxidant activity in commercial oyster mushrooms and phellinus mushrooms . The total phenol content varied from 3488.2 to 7161.9 g g-1 in oyster mushroom(Pleurotus spp.). The total phenol content varied from 23390.3 to 26878.3 g g-1 in phellinus mushroom, containing about from four times to seven times more than oyster mushrooms. Among the seventy nine oyster mushroom varieties examined, Bupyeongsoyeob had the highest total phenol content and Keunneutari 1 had the lowest total phenol content. Most of king oyster mushroom(Pleurotus eryngii) varieties and ferula oyster mushroom(Pleurotus ferula)had tendency of low total phenol content. EDA(Electron Donating ability) using DPPH varied from 9.3 to 73.6% in according to oyster mushroom varieties. Most of king oyster mushroom had low antioxidant activity. We believe that the content of functional substances like total phenol content and the antioxidant activities in commercial oyster and phellinus mushrooms could be improved and such varieties strengthed might be selected for the utilization of future breeding resources, based from the results of our study.
        32.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the biological treatment of industrial wastewater containing high concentration of phenol, isolation and characterization of phenol - degrading bacterium were carried out. A bacterial strain P2 capable of degrading phenol was isolated from contaminate
        4,000원
        33.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alkylation of phenol with tert-butanol in the liquid phase on mordenite was studied. The influence of many reaction parameters such as calcination temperature, reaction temperature, t-butanol/phenol molar ratio on catalytic properties was discussed. The main products were 2,4-di-t-butylphenol, o-t-butylphenol, p-t-butylphenol, the last of these was wanted product. In order to enhance the selectivity of p-t-butylphenol, optimum conditions were recommended at 500℃ calcination temperature, 140℃ reaction temperature, 1.0 molar ratio of reactants over mordenite. P-t-butylphenol was formed with 90% isomer selectivity at optimum conditions after 4hr reaction. On the basis of the behavior obtained in the cases mentioned, optimum conditions and catalytic properties for t-butylation of phenol were provided.
        4,000원
        35.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        다양한 수질 오염원 중 페놀과 같은 유기화합물은 배출조건이 비정상적인 경우 기존의 처리방법으로 제거하거나 파괴하기 어렵다. 수용액으로부터 페놀을 분리하기 위한 최근의 연구들은 활성탄에 의한 흡착, 용매 추출 등에 의해 수행되어져 왔으며, 물-기름 유화에 기초를 둔 액막법이 기존의 기술들을 대체하기 위한 방법으로 시험되어져 왔다. 본 연구에서는 tri-n-butyl phosphate(TBP)와 액상 고분자를 지지액막의 액막용액으로 선정하여 수용액상의 페놀을 분리하였다. 공급측 페놀 농도를 변화시키고 다양한 액막용액을 사용하여 이들이 페놀분리에 미치는 효과를 연구하였다. TBP를 운반체로 사용한 경우의 실험결과들은 용매추출에서 주로 사용되고 있는 methyl isobutyl ketone(MIBK)보다 높은 물질전달속도를 보여주었으며, 선택한 액상고분자 중 polypropylene glycol 4000(PPG-4000), polybutylene glycol 500(PBG 500)의 경우 MIBK와 유사하거나 조금 높은 값을 나타내었다.
        4,000원
        36.
        1996.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 흡착과 막분리를 결합시킨 혼성 시스템을 폐수처리에 응용하기 위한 기초 연구로서, 페놀을 분말활성탄에 의해 흡착하고, 흡착된 페놀을 활성탄과 함께 정밀여과에 의해 분리하였다. 분말활성탄의 입자크기가 클수록 여과저항은 감소하였으며, 활성탄의 양이 적을수록 단절점(break point) 이전의 투과농도 변화율과 페놀 부하 변화율은 증가하였다. 분말활성탄의 입자크기가 작을수록 활성탄의 외표면적과 경막물질전달계수의 증가로 인해 단절점 전의 투과농도는 감소하였다.
        4,000원
        37.
        1996.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cinnamoyl ester(PGEFC) of poly(phloroglucinol-formaldehyde) glycidyl ether which has photosensitive functional group was prepared to apply to photoresist. Photosensitivity of PGEFC was estimated by the solubility difference in organic solvent before and after exposure to light. The yield of residual film was calculated by immersing the sample-coated quartz plates in the solvent which was used in coating. The yield of the residual film which was closely related to the sensitivity of the film, was affected by the degree of polymerization of the backbone resin, sensitizers and their concentration. The sensitivity was depended upon the degree of polymerization. Most of effective sensitizer for PGEFC among the sensitizers was 2, 6-dichloro-4-nitroaniline.
        4,000원
        38.
        1995.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Three potato cultivars, Sumi,Daejima and Namjak, were prepared as slices. They were dipped in distilled water for 20 seconds. The potato slices were packed in polyethylene bags and stored at 5℃. Browning degree, total phenol and chlorogenic acid contents and polyphenol oxidase (PPO) activity were measured. And the correlation analysis of browning parameters were conducted. The results were as follows. There were increase in browning degree, phenolic content and PPO activity during cold storage of potato slices with different cultivars. Among three cultivars, Sumi showed the highest browning degree, phenolic content and PPO activity and also showed the highest % increse of browning and PPO activity during cold storage. On the contrary, Daejima was the lowest. But Daejima showed the highest % increase in phenolic contents during cold storage. With Sumi, browning degree was significantly correlated with PPO activity and phenolic contents (p〈0.05). With Daejima and Namjak, a significant correlation was found between browning degree and PPO activity (p〈0.05). From the above results, enzymatic browning reactions of potato slices and factors affecting them were dependent on cultivar. Among the tested three cultivars, Daejima showed the lowest browning degree during cold storage and thus seems to be desirable for minimal processing.
        4,000원
        39.
        1994.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is well known that the adsorption character of activated carbon is dependent on the specific surface area and pore volume, but the relationship between the surface-chemical structure and the adsorption character has not been studied very often. The purpose of this study is to investigate the effect of the acidic surface functional groups of activated carbon and the adsorption characteristics of low concentration phenol. So three types of activated carbons and four different treatments were introduced to this isotherm experiment. These treatments were nontreatment, 1N $HNO_3$ treatment, 6N $HNO_3$ treatment, $H_2O_2$ treatment. The conclusions of this study are as followings. If the initial concentration of phenol is high as 5mg/l, the adsorption is dependent on the specific surface area. If the initial concentration of phenol is low as $100{\mu}g/l$, the adsorption is dependent on the average pore volume. The acidic surface functional groups prevent the adsorption of phenol molecules to activated carbon. And the adsorbed amount decreases more for $HNO_3$ treatment than for $H_2O_2$ treatment and more for concentrated $HNO_3$ treatment than for dilute $HNO_3$ treatment.
        4,000원
        40.
        1994.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the rapid industrialization, an ever-increasing quantity and kind of new organic compounds pose environmental problems due to their toxicity and physiological effect. However, research on the biodegradation of these compounds under anaerobic condition is very limited inspite of its efficiency and economical advantage. In this research, the pH effect on the ring cleavage of phenol under anaerobic condition was investigated, and the theory of phase separation was applied to the degradation of phenol for investigating the role of acidogenic bacteria. Results, obtained from biochemical methane potential(BMP) assay for 15.5 days of incubation, showed that acidic condition was more desirable for phenol degradation than alkaline condition. By both unacclimated methanogenic granular sludge and two mixed cultures, phenol was completely removed within six weeks of incubation with a gas conversion rate of over 86% of theoretical one. However, phenol was not degraded by unacclimated acidogenic culture, and thus it is considered as a syntrophic substrate. In case of phase separated biochemical methane potential(PSBMP) assay, in which acidogenic and methanogenic culture were seeded separately and consecutively, those that had been subjected to normal acidogens for 3 to 4 weeks showed higher gas production than those seeded with sterile or frozen culture.
        4,000원
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