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        검색결과 34

        1.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, blending oils of diesel oil and butanol were used as fuel oil for diesel engine to measure combustion pressure, fuel consumption, air ratio and exhaust gas emission due to various operating conditions such as engine revolution and torque. Using these data, the results of analyzing the engine performance, combustion characteristics and exhaust emission characteristics such as NOx (nitrogen oxides), CO2 (carbon dioxide), CO (carbon monoxide) and soot were as follows. The fuel conversion efficiency at each load was highest when driven in the engine revolution determined by a fixed pitch propeller law. Except 30% butanol blending oil, fuel conversion efficiency of the other fuel oils increased as the load increased. Compared to diesel oil, using 10% and 20% butanol blending oil as fuel oil was advantageous in terms of thermal efficiency, but it did not have a significant impact on the reduction of exhaust gas emissions. On the other hand, future research is needed on the results of the 20% butanol blending oil showing lower or similar levels of smoke concentration and carbon monoxide emission rate other than those types of diesel oil.
        4,000원
        2.
        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
        3.
        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
        4.
        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
        5.
        2019.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.
        4,000원
        6.
        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
        7.
        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
        8.
        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.
        9.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        FASs (fluoroalkylsilanes)로 표면 개질한 소수성 막에 대한 부탄올/물, 이소프로판올/물 용액의 수착(sorption)량을 측정하였으며 이들 수착 특성을 Hansen 용해도 파라미터를 이용하여 해석하였다. 부탄올의 수착량이 이소프토판올보다 많았으며, 이는 부탄올의 용해도 파라미터(δt = 20.4)와 FASs 소수성 막의 용해도 파라미터(δt = 16.9)와의 차이가 이소프로판올 (δt = 24.6)과의 차이보다 작기 때문인 것으로 설명할 수 있다. 극성력(δp) 측면에서 살펴보면, FASs 극성력(δp = 4.6)과 부탄올의 극성력(δp = 6.3)과의 차이가 FASs 극성력(δp = 4.6)과 이소프로판올의 극성력(δp = 9.0)과의 차이보다 작다. 이는 부탄올-FASs 간의 극성력 차이가 이소프로판올-FASs 간의 극성력 차이보다 작아서 부탄올-FASs 간의 상호인력이 크다는 것 을 의미하며, 수착량이 크게 나타나는 결과를 설명할 수 있다. 본 실험결과로부터 막에 대한 알코올의 수착특성, 용매에 대한 용질의 용해도 등을 분석하는데 용해도 파라미터를 이용할 수 있음을 알 수 있다.
        4,000원
        10.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 (주)파인텍에서 제조한 제올라이트 4A 분리막을 이용하여 물/메탄올, 물/부탄올 혼합물의 투과증발 실험을 수행하였다. 분리막을 투과한 기체분자들은 액체질소트랩을 이용하여 포집하였으며, 기체크로마토그래피(TCD)를 이 용하여 혼합물의 조성을 분석하였다. 실험을 통해 물과 메탄올(분리계수 최대 250 이상), 물과 부탄올(분리계수 최대 1,500 이상)의 혼합물에서 선택적으로 물을 분리하는 것을 확인하였다. GMS (generalized Maxwell Stefan) 이론을 적용하여 2성분 계의 투과증발 거동을 모사하였으며, 상수추정을 통하여 제올라이트 비지지체의 흡착상수 및 확산상수를 구하였다. 제올라이 트 4A 분리막의 경우 기공의 크기가 물보다는 크고, 메탄올, 부탄올 보다는 작기 때문에, 알코올로부터 물을 분리시키는 공정 에 적용시킬 수 있다. 바이오 에탄올 분리, 부탄올 분리, 막반응기, 하이브리드 반응-탈수 공정 등에 적용할 수 있을 것으로 사료된다.
        4,300원
        11.
        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
        12.
        2017.11 구독 인증기관·개인회원 무료
        이산화탄소를 이용한 메탄올 합성반응과정에서 생성되는 물, 메탄올, 부탄올로 이루어진 혼합용액에서 제올라이트 분리막을 이용하여 물을 분리시키기 위해 투과증발실험을 진행하였다. 투과증발실험에서 사용된 분리막은 ㈜파인텍에서 합성된 제올라이트 분리막을 공급받아 사용하였다. 투과증발실험에서는 물을 분리하는 성능을 확인하기 위해 가스크로마토그래피 등의 실험장비와 성능지표 를 나타내는 계산식들을 사용하였다. 실험을 통해 물과 메탄올(분리계수 최대 250 이상), 물과 부탄올(분리계수 최대 1500 이상)의 혼합물에서 선택적으로 물 을 분리하는 것을 확인하였다. GMS (Generalized Maxwell Stefan) 이론을 적용 하여 2성분계의 투과증발 거동을 모사하였으며, 상수추정(parameter estimation) 을 통하여 제올라이트 비지지체의 흡착상수 및 확산상수를 구하였다.
        13.
        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.
        14.
        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
        15.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Butanol has an ability to improve the ignition quality due to its lower latent heat of vaporization; it has an advantage to reduce a volume of a fuel tank because its energy density is higher than that of ethanol. Also, butanol-diesel oil blending quality is good because butanol has an effect to prevent the phase-separation between two fuels. Even if the blended oil contains water, it can reduce the corrosion of the fuel line. Thus, it is possible to use butanol-diesel oil blended fuel in diesel engine without modification, and it may reduce the environment pollution due to NOx and particulate and the consumption of diesel oil. Therefore, some studies are being advanced whether butanol is adequate as an alternative fuel for diesel engines, and the results of the combustion and exhaust gas emission characteristics are being presented. Though the injection and spray characteristics of butanol are more important in diesel combustion, the has not yet dealt with the matter. In this study, the influence in which differences of physical properties between butanol and diesel oil may affect the injection and spray characteristics such as injection rate, penetration, spray cone angle, spray velocity and process of spray development were examined by using CRDI system, injection rate measuring device and spray visualization system. The results exhibited that the injection and macroscopic spray characteristics of two fuels were nearly the same.
        4,000원
        17.
        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
        18.
        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
        20.
        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
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