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        검색결과 18

        1.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        양이온 계면활성제인 tetradecyltrimethylammonium bromide (TTAB)에 의한 크레졸 이성질 체의 가용화에 미치는 치환기, 온도 그리고 NaCl과 n-부탄올과 같은 첨가제의 효과를 UV-Vis법으로 측정하였다. 가용화상수(K8)값은 o-크레졸<m-크레졸<p-크레졸 순으로 증가하였으며, 온도의 증가에 따라 이들 K8값은 감소하였다. 크레졸 이성질체들의 가용화에 대하여 계산한 ΔG0값과 ΔH0값은 모두 음의 값을 나타내었다. 그러나 ΔS0값은 모두 양의 값을 나타내었다. 또한 ΔG0값은 n-부탄올의 농도가 증가할수록 증가하는 경향을 그러나 NaCl의 농도가 증가할수록 더욱 감소하는 경향을 보였다. 이러한 사실들로부터 크레졸 이성질체들의 가용화에는 엔탈피와 엔트로피가 동시에 기여하고 있으며, 또한 크레졸분자들이 가용화되는 위치는 미셀의 표면이나 palisade층에서 주로 이루어짐을 알 수 있다.
        4,000원
        2.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Eruca sativa (E. sativa)는 루꼴라라고 불리우고 이탈리아 요리에 많이 사용되는 식물로 Brassicaceae 속에 속하는 다년생 식물이다. E. sativa를 70% 에탄올로 환류추출 및 농축하고 (ES), n-hexane (EHex), ethyl acetate (EEA), chloroform (ECHCl3), n-butyl alcohol (EBuOH) 및 water (EDW) 용매 극성별로 분획하여 미백 효능을 규명하고 화장품 소재로서의 응용성을 연구하였다. ES, EHex, EEA, ECHCl3, EBuOH 및 EDW의 mushroom tyrosinase 활성 저해를 평가한 결과 EEA가 가장 유의하게 저해하였으며, B16F10 멜라노마 세포 내에서의 멜라닌 생성을 확인한 결과 ES, EEA 및 EBuOH 를 처리하였을 때 멜라닌 생성이 유의하게 저해되었으며, 특히 EEA 분획물에서 가장 효과가 뛰어났다. 피부염과 여드름을 일으키는 황색포도상구균, 여드름 원인균을 포함한 8종의 세균, 진균에 대해 ES, EHex, EEA, ECHCl3, EBuOH 및 EDW의 항균력과 방부력 시험을 평가한 결과 EEA는 8종의 균 모두 효과적으로 항균력을 나타냈다. ES를 0.05, 0.1%를 함유하여 제조한 토너와 에멀션은 기존 처방에서 방부력을 증가 시켜 천연보존제 역할을 할 수 있을 것으로 판단된다. ES를 토너, 에멀션 제형에 0.05, 0.1%로 첨가하여 일광, -20, 4, 25, 55 ℃ 조건에서 4 개월동안 안정성을 평가한 결과 pH 및 점도에 대한 영향은 크게 없었 으나 대조군 및 ES를 첨가한 에멀션 55 ℃에서 분리가 일어나는 것을 확인하였다. 또한, 피부침투시험을 통해 EEA는 6 hr에서 0.058%가 침투되어 임상적인 효능을 예측할 수 있었다. 천연소재 E. sativa는 미백 기능성화장품 소재 및 천연 항균 보존제로 활용 가치가 있을 것으로 사료된다.
        4,200원
        3.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        n-Butanol is used to assess how odor intensity correction affects judges’ evaluation of the odor intensity based on the concentration. The odor intensity correction effect is verified by using three types of test solutions which are used for the selection of judges based on their concentration levels. The correction effect is statistically analyzed according to gender, odorant type, and concentration on the group and individual level. The result shows that n- Butanol correction affects the odor intensity evaluation for three odorants in different ways. In most cases, n- Butanol correction increases the panelists' sensitivity to the odor intensity change, and results to be close to the theoretical value. The female panelists can more accurately evaluate the sourness intensity of acetic acid after n- Butanol correction. All panelists regardless of gender can more accurately evaluate the fishiness intensity of trimethylamine after n-Butanol correction. For evaluating the caramel smell intensity of methylcyclopentenolone, a full panel without n-Butanol correction is recommended. Therefore, n-Butanol correction should be included in the process of judge selection and the odor intensity assessment.
        4,300원
        4.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The stench of various sources has become a complex issue that all governments must face and solve. n-Butanol is often used as an odor intensity reference for daily air quality monitoring and evaluation. However, its odor space, including odor sensation and odor effect, is still not fully understood, especially in wide concentration ranges. This study described n-butanol odor character profiles with objective descriptors. They are mostly presented as “odorless” or “offensive” at low concentrations, and frequently characterized as “chemical” or “medicinal” at high concentrations. The semantic differential shows that n-butanol odor is a negative emotional odor rather than a positive one. The principal component analysis shows that the representative factors of the n-butanol sensibility structure according to the sensibility evaluation are expressed with diverse sensibility vocabulary, and ‘esthetics’ represent its characterless nature. The good linearity between intensity and concentration, the near absence of gender difference, diverse odor types rather than a specific type, and ease with which to make a wide range of concentrations, makes n-butanol a candidate to be considered as a suitable standard odorant.
        4,000원
        5.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        아닐린 수용액에서의 암모늄형 양이온성 계성면활성제 (DTAB, TTAB 및 CTAB)의 미셀화에 대한 임계미셀농도(CMC)값을 UV-Vis법으로 측정하였다. 290K ~ 314K 사이에서 측정된 양이온성 계면활성제의 CMC값의 변화로부터 미셀화에 대한 Gibbs 자유에너지(ΔG⁰)값을 구하고, 이 값으로부터 엔탈피(ΔH⁰)와 엔트로피(ΔS⁰)를 계산하고 분석하였다. 또한 n-부탄올 및 염화나트륨의 농도 변화가 미셀화에 미치는 영향을 열역학적 함수를 이용하여 비교·분석하였다. 실험한 온도 구간 및 첨가제의 농도 범위 내에서 측정된 모든 ΔG⁰ 값은 음의 값을 나타냈었으며, 엔탈피(ΔH⁰) 변화값은 모두 음의 값을 그리고 엔트로피(ΔS⁰) 변화값은 모두 양의 값을 나타내었다. 아닐린 수용액에서 양이온성 계면활성제의 미셀화는 자발적 발열반응이며, 열역학적 값들로부터 계산된 등구조온도에 의하면 이들 계면활성제의 미셀화는 엔탈피(ΔH⁰)와 엔트로피(ΔS⁰)가 거의 동일하게 기여하고 있음을 알 수 있었다.
        4,000원
        6.
        2018.11 구독 인증기관·개인회원 무료
        High performance polydimethylsiloxane (PDMS) membranes for n-butanol recovery were fabricated using a tri-functional crosslinker containing the phenyl group. In order to understand the role of the functional group structure and cross-linking density in pervaporation performance, PDMS membranes were prepared using tri-functional crosslinker containing other functional groups (hexyl and cyclohexyl) and conventional tetra-functional crosslinker. The relationship between the polymer structure-performance was discussed based on the sorption and diffusion properties of the membranes. As a result, the phenyl-based PDMS membrane exhibited the pervaporation performance owing to the strong hydrophobicity and chain rigidity of the phenyl group compared to other PDMS membranes even at high butanol concentration and high temperature conditions.
        7.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The autoignition characteristics of n-heptane/n-butanol were investigated both experimentally and numerically. The effects of oxygen concentration and exhaust gas recirculation rate on the autoignition characteristics were evaluated. A rapid compression machine was employed to measure ignition delay times of blended fuels. A numerical study on the ignition delay time was performed using the CHEMKIN-PRO software to calculate ignition delay time and predict the chemical species in the combustion process. The results revealed that the ignition delay time increased with decreasing oxygen concentration due to the thermal load effect of nitrogen. The oxidation reaction of n-heptane in a low temperature regime was limited with decreasing oxygen concentration. The ignition delay time sharply decreased with exhaust gas recirculation because of the intermediate species in the exhaust gas. Exhaust gas recirculation reduced first ignition delay dramatically. However, the time interval between the first and main ignition increased with increased exhaust gas recirculation.
        4,000원
        8.
        2017.11 구독 인증기관·개인회원 무료
        Polydimethylsiloxane (PDMS) membranes were fabricated using a new class of UV-curable PDMS (UV-PDMS) and conventional heat-curable PDMS (Heat-PDMS) materials for n-butanol recovery. In addition, mixed matrix membranes (MMMs) were prepared using silicalite-1 particles as a additive to improve the recovery efficiency of n-butanol. To understand the structure-performance relationship, the surface/cross-sectional morphology and roughness of the PDMS membranes and MMMs were characterized using SEM and AFM, respectively. Consequently, when 20 % of silicalite-1 particles was loaded, the UV-curable MMM exhibited 58 % increased flux with similar separation factor compared to the heat-curable MMM, which is attributed to enlarged the effective membrane surface area resulting from its unique morphology.
        9.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The gas sensor sensitivity value of three methods (simple application method, vaporization method, and chamber method) were compared in order to establish a method for the measurement of liquid odor substances. In order to select the representative sensors from among the 16 sensors constituting the gas sensor array, cluster analysis, regression analysis, and correlation analysis were performed. Sensors with excellent correlation in terms of reactivity were selected as representative sensors of each measurement method. As a result, it was shown that the reactivity and the correlation increased in the order of simple application method < vaporization method < chamber method. Through a variance analysis using the sensitivity values of selected representative sensors, it was shown that the simple application method had statistical significance at the level of 99.9% (p<0.001) in three of the representative sensors in four clustering groups. The vaporization method and the chamber method showed statistical significance at a level of 99.9% (p<0.001) for all representative sensors in each clustering group. If the reactivity were improved by controlling the sensitivity of the sensor, the simple application method and vaporization method could also be used as a method of measuring the liquid material with gas sensor array.
        4,000원
        11.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In Korea, yam with thermal treatment is widely used to produce tea and beverage, which appeals to all age groups. To better understand the antioxidative activity of thermal treatment yam (Dioscorea batatas DECNE.), n-butanol and ethyl acetate extracts were evaluated with different antioxidant testing system. Their antioxidant activities, including ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power as well as total phenol contents were assessed in vitro. Results showed ethyl acetate extract (51.63±2.51 mg CAE/g) possessed similar total phenol content compared with n-butanol extract (53.93±1.00 mg CAE/g). Ethyl acetate extract also exhibited similarly stronger antioxidant activity compared with n-butanol extract apart from ABTS radical scavenging activity assay.
        4,000원
        12.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed at evaluating the antioxidant activity of raw yam (Dioscorea batatas DECNE.) extracted by n-butanol and ethyl acetate. The antioxidant activities, including ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power as well as total phenol contents were studied in vitro. Results showed ethyl acetate extract (111.88±0.66 mg CAE/g) possessed higher total phenol content than n-butanol extract (78.68±0.58 mg CAE/g). Ethyl acetate extract exhibited stronger antioxidant activity compared with n-butanol extract apart from reducing power assay.
        4,000원
        13.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        n-Butanol and ethyl acetate extracts of thermal treatment yam (Dioscorea batatas DECNE.) belonging to the family Dioscoreaceae were measured for their radical scavenging activity and lipid peroxidation inhibition ability. In this study, ethyl acetate extract showed the most potent antioxidant activity evaluated by ferrous ion chelating activity and NO radical scavenging activity. Nevertheless, n-butanol extract was more effective in inhibiting linoleic acid peroxidation. A significant difference between n-butanol extract and ethyl acetate extract in nitrite scavenging activity β-carotene bleaching assays could not be found. Also, the results of this study showed that thermal treatment yam could be used as easily accessible source of natural antioxidants and as a possible food supplement.
        4,000원
        14.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, n-butanol and ethyl acetate extracts were prepared from raw yam (Dioscorea batatas DECNE.). Their antioxidative potencies were investigated employing various in vitro methods, such as ferrous ion chelating, β-carotene bleaching assay, lipid peroxidation inhibition and nitric oxide (NO) radical scavenging and nitrite scavenging activity. The n-butanol fraction was assayed to possess stronger antioxidant activity by β-carotene bleaching assay, lipid peroxidation inhibition and NO radical scavenging activity. However, ethyl acetate extract was more effective in chelating ferrous ion and scavenging nitrite. Based on the results obtained, yam is a potential active ingredient that could be applied in antioxidation as well as bio-health functional food to take a good part in prevention of human diseases and aging.
        4,000원
        15.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 Pebax-2533 판형 분리막을 1-프로판올과 n-부탄올 혼합용매를 이용하여 용해, 건조하여 제조하였고 time-lag 장치를 이용하여 CO2, N2 투과특성을 평가하였다. 제조된 분리막은 평가조건에 따라서 130-288 barrer의 CO2 투 과율을 가졌으며, CO2/N2 투과선택도는 5-8이었다. Time-lag 장치의 주입부 압력이 증가함에 따라서, 투과온도가 낮아짐에 따라서, 그리고 혼합용매의 n-부탄올 양이 증가함에 따라서 CO2 투과도는 감소하였다. 이러한 실험 자료는 Pebax-2533 분리 막의 CO2 투과율이 CO2 용해에 매우 의존할 것이라 예측과 달리, CO2 용해뿐만 아니라 CO2 확산도 매우 중요한 단계임을 의미하였다.
        4,000원
        16.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        소수성 ZSM-5 분리막을 결정성장핵의 수열합성 2차 성장법으로 다공성 스테인레스 스틸 지지체의 안쪽에 합성하였으며, 이렇게 제조한 분리막을 이용하여 n-부탄올 수용액으로부터 n-부탄올을 선택적으로 분리하였다. 공급 수용액의 농도 변화 및 운전 온도의 변화에 따른 투과증발 특성을 관찰하였다. 공급 수용액 내의 n-부탄올 농도를 각각 0.001, 0.005, 0.01 그리고 0.015 몰분율로, 운전 온도는 25C, 35℃ 그리고 45℃로 바꾸면서 실험하였다. 운전 온도가 45℃인 실험조건에서 공급측 n-부탄올의 몰분율이 0.001에서 0.015로 증가함에 따라 n-부탄올의 플럭스는 약 2g/㎡/hr 에서 27g/㎡/hr 로 크게 증가하였다. 이 결과로 투과물 내의 n-부탄올의 농도가 0.0016 몰분율에서 0.052 몰분율로 상당히 증가함을 알 수 있었다. 공급 농도가 0.015인 상태에서 운전 온도가 25℃에서 45℃로 증가함에 따라 n-부탄올의 플럭스는 약 13g/㎡/hr 에서 27g/㎡/hr 로 크게 증가하였으며, 투과물 내의 n-부탄올 농도도 따라서 0.045에서 0.052로 증가함을 관찰할 수 있었다.
        4,000원
        17.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 PVDF/PDMS 복합막을 제조하여 부탄올을 농축을 위한 투과증발특성에 대해 알아보았다. 또한 복합막의 제조 방법에 따른 투과특성을 알아보기 위해 지지층의 PVDF 농도변화와 활성층의 경화조건에 따라 투과증발 최적막을 선정하였다. 이 막을 사용하여 공급액의 농도, 온도 및 순환 유속을 변화시켜 부탄올의 투과특성에 미치는 영향에 대해 알아보았다. 그 결과 공급액의 농도, 온도, 순환 유속이 증가할 경우 부탄올의 플럭스와 투과 농도가 증가함을 확인하였으며 상용막인 GKSS사의 PVDF/POMS 복합막과 비교한 결과 부탄올 투과 플럭스, 투과 농도, 선택도 등 모두 높은 값을 나타내었다.
        4,000원
        18.
        2016.10 서비스 종료(열람 제한)
        Background : This study, the fraction for testing the efficacy of the Astragalus extract was concentrated active ingredient. The concentrated fraction was applied to a cosmetic material that Astragalus testing results confirmed that the improved efficacy. Methods and Results : The fractions were performed using an n-butanol solvent for increasing the efficacy of the Astragalus extract, by using the material fractions collected to compare and ultimately an increase in whitening and wrinkle efficacy. The solvent to be used in the fractions was used for the n-butanol good dissolution to the effective substance(Astragaloside, Isoflavonoid). It increased approximately 6.5 times the sample extract and the n-butanol fraction of the Astragalus as a result Astragaloside 15 ppm, 97 ppm respectively analyzed by HPLC equipment, isoflavonoid content was confirmed by an increase in the content of the fractions increased 4.5 times to 280 ppm, 1,260 ppm. Tyrosinase inhibitory effect, respectively IC50 5.70 mg/mL, IC50 1.02 mg/mL to, Collagenase producing ability is IC50 4.88 mg/mL, IC50 0.93 mg/mL with n-butanol fraction was good whitening, anti-wrinkle efficacy than the extract. Sensory evaluation was conducted in the same amount of sample, using a purified Astragalus cosmetics received high marks. Stability evaluation(MTT assay) was checked for more than 100% cell viability at the concentration 2,000 ppm. Conclusion : n-butanol fraction of Astragalus was subjected to a component analysis and In vitro test, it was confirmed an increase active ingredient content. The results of sensory evaluation and stability evaluation, it was confirmed been made to improve qualities as a cosmetic materials.