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        검색결과 85

        61.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        곤충생태원을 인공적으로 조성한 후 곤충의 다양성 변화를 조사하고 기주식물과의 관계를 구명하고자 조성 후 1년 차인 1998년부터 2001년까지 4년간 발생하는 곤충 종을 조사하였다. 식재 4년차인 2001년 4월부터 11월까지 조사된 곤충으로 총 11목 138과 343종 5,744개체가 채집되었다. 곤충의 발생은 4월부터 7월 사이에 다양한 종이 출현하였으며, 특히 6월 말에 가장 많은 곤충 종들이 출현하였고 딱정벌레목의 곤충이 종 및 개체수에서 가장 많았다. 우점종으로는 딱정벌레목의 등빨간먼지벌레, 나비목의 배추흰나비, 노린재목의 투명잡초노린재 순이었다.
        4,000원
        67.
        2000.09 구독 인증기관 무료, 개인회원 유료
        골재의 입도에 따른 SBS 개질 아스팔트 혼합물의 점탄성 물성 및 피로공용 특성을 소개하였다. 아스팔트 바인더와 혼합물의 열역학적 거동분석을 위해 DSR 시험과 일축인장 크립시험을 실시하였다. 골재의 입도와 SBS 개질재가 피로공용성에 미치는 영향을 평가하기 위하여 7종의 아스팔트 혼합물에 대해 일축인장 피로시험을 실시하였다. DSR 및 일축인장 크립시험결과, 골재의 입도에 관계없이 SBS 개질 아스팔트 혼합물이 일반 아스팔트 혼합물에 비해 고온에서 소성변형에 대한 저항성이 큰 것으로 나타났다. Superpave 아스팔트 바인더 규격의 피로인자 G*sinδ는 아스팔트 혼합물의 피로 공용성 평가에 사용하기에는 부적절한 것으로 사료된다. 일축인장피로시험결과, 골재의 입도(밀입도, Superpave입도, SMA입도)에 관계없이 SBS 개질 아스팔트 혼합물이 일반 혼합물에 비해 약 10배 이상 피로수명이 큰 것으로 나타났다. 장기노화후의 경우에 있어서도 SBS 개질 혼합물의 피로수명이 일반 혼합물에 비해 높게 나타났다. 골재의 입도변화는 SBS 개질재에 비해 피로공용성에 미치는 영향이 적었다. SMA 혼합물에 첨가한 셀룰로오스 섬유는 혼합물의 점탄성 물성이나 피로공용성에 미치는 영향이 미미하였으나, Draindown을 방지하는 데는 효과적이었다. SMA 입도에 SBS 개질아스팔트를 사용할지라도 Draindown 방지를 위해서는 셀룰로오스 섬유를 첨가할 필요가 있을 것으로 사료된다.
        4,900원
        70.
        1994.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was done to evaluate the effects of grape variety, pH and sugar contents on textural and sensory properties of grape pectin jelly. As a gelling agent, pectin 1% was selected due to highest sensory scores in preparatory experiments and also nutritional and economical reasons. To get the proximate composition of grape extract, moisture, pH, reducing sugar, and total titratable acidity was measured. Grape pectin jellies, made by 12 different recipies, were tested by sensory and instrumental evaluatoin. The results were as follows; 1) Hardness and chewiness were lowered in grape jelly which has lower pH and lower sugar contents. 2) People preferred grape jelly which has lower hardness, brittleness and sweetness, and higher sourness. 3) Comparing overall quality, Recipe C1 in Jelly 1 and recipe B1 in Jelly 2 were chosen as best. 4) Sensory hardness showed positive correlation with instrumental hardness, brittleness and chewiness.
        4,000원
        71.
        2021.12 KCI 등재 서비스 종료(열람 제한)
        비전통(unconventional) 에너지 자원 중 최근 각광받고 있는 셰일 가스의 회수율을 높이기 위해서는 저류층의 공극 구조 연구가 필수적이다. 본 연구에서는 대면적으로 입자나 형상 분포를 확인 할 수 있도록 개발된 분석 장치인 대면적 자동화 입자 분석 시스템(Scanning Electron Microscope Particle Analysis, SELPA)을 활용하여 셰일 가스 저류층 시료의 공극 분포를 관찰하였다. 본 연구에서는 리아드 분지에서 시추된 A-068 시추공 시료 중 방해석이 주 구성 광물인 시료를 대상으로 연구를 수 행하였다. SELPA를 이용하여 시료 내 수십 나노에서 수백 마이크로미터 크기의 공극을 관찰하였 고 각 공극의 크기 별 비율을 확인하였다. 같은 영역의 표면을 대상으로 각각 1000배, 3000배, 5000 배의 배율로 이미지를 관찰하여 공극의 분포를 확인한 결과 최소 3000배 이상의 배율에서 관찰 해야 100 nm 이하의 공극까지 관찰되어 작은 스케일의 공극 분포까지 분석할 수 있는 것이 확인 되었다. 본 연구에서 소개된 방법론을 통해 셰일 가스 저류층을 포함한 비전통 자원의 저류층 내 공극의 분포를 단시간에 파악할 수 있는 방법론이 확인되었으며 향후 비전통 저류층 내 공극 구 조 파악에 활용할 수 있을 것이 기대된다.
        72.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        비전통 저류층에서 에너지 자원의 회수율을 높이기 위해서는 저류층 내의 미세 공극 형태와 연결도 등을 포함하는 공극 구조 연구가 필수적이다. 본 연구에서는 셰일 저류층 내 나노스케일의 공극 구조 연구에 적합한 조건과 방법을 찾기 위해 집속 이온 빔 시스템(Focused Ion Beam, FIB)과 이온 밀링 시스템(Ion Milling System, IMS)을 이용하여 분석을 진행하였다. 셰일 저류층 내 공극 구조 연구를 위해 리아드 분지에서 획득된 A-068 시추공의 시료를 사용하였다. 각 시료마다 특성이 다르기 때문에 시료 전처리 방법과 조건을 달리하여 최적의 조건을 찾았고 FE-SEM을 이용하여 공극 이미지를 획득하였다. 연구 결과 국소 부위의 공극구조를 관찰하기 위해서는 FIB를 사용하여 시표 표면을 밀링 후 바로 공극 이미지를 얻는 것이 효율적이고 반면에 넓은 면적을 단시간에 밀링하여 여러 공극 구조를 관찰하기 위해서는 IMS를 이용해야 한다는 것을 확인했다. 특히 탄산염 광물 함량이 높고 강도가 큰 암석에 대해서는 FIB보다는 IMS를 활용하여 밀링을 수행해야 공극 구조 관찰이 가능하다는 사실이 밝혀졌다. 본 연구를 통해 셰일 저류층 내 공극 구조 관 찰을 위한 방법이 정립되었으며 향후 이를 이용한 셰일 가스 저류층 시료 분석을 통해 공극의 크기나 형태 가 셰일가스 회수 증진에 미치는 영향을 밝힐 수 있을 것이다.
        73.
        2018.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the quality of fresh-cut lettuce after a washing treatment with aqueous thyme extracts of differing concentration. Four different concentrations of thyme extract were employed: 0.001% (w/v, TEA), 0.005% (w/v, TEB), 0.01% (w/v, TEC), 0.05% (w/v, TED), while distilled water was used as a control. Measurements of O2 concentration, CO2 concentration, total aerobic bacteria, CIE L*, a*, b*, browning index, total phenolic contents and enzymatic activities were investigated on day 0, 1, 3, 5, and 7 at 10 . The O2 concentration in TEB were higher than those in other samples during storage, and the CO2 concentration in TEB and TEC were significantly lower than in other samples on day 7. There was no significant difference in the total aerobic bacteria counts between treatments (p<0.05). The samples treated with TEB and TEC showed higher L* (lightness) values, but lower browning indexes, total phenolic compound levels, and enzymatic activities (polyphenol oxidase, peroxidase) than other samples during storage. Specifically, on day 7, the browning index of Cont reached 0.25, while those in the TEB and TEC were about 0.15. The L* in Cont decreased from 69.50 to 58.92, while TEB and TEC were values of 65.61 and 63.20, respectively. These results reveal that 0.005-0.01% thyme extract was effective as a washing treatment inhibited the browning of fresh-cut lettuce and is thus expected to be a useful natural extract for maintaining the quality of fresh-cut lettuce.
        74.
        2018.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The purpose of this study is to present the results as basic data for establishing proper storage conditions and distribution conditions of actual farms at point of increasing concern about hygiene and palatabiltiy of consumers to food. In this study, three farmhouses of dried persimmons prepared using different storage conditions were selected in Sangju (Korea). The dried persimmons were stored for 90 days. Changes in temperature and humidity were measured with a temperature and humidity recorder under each storage condition, and physicochemical analysis and sensory evaluation were performed. The average temperatures of farmhouse A, B and C were approximately -22--23℃, -19--18℃ and -25℃ respectively. The humidities of A, B and C were 62-63%, 59-60%, and 66-67%, respectively, and the moisture contents of all farmhouses increased during the storage period, with farmhouse B showing the most rapid increase. Free sugars increased, except for those from farmhouse C. Persimmons from farmhouse B showed the greatest changes in chewiness and hardness. The values of a* and b* were significantly decreased in persimmons from farmhouse B, and the color difference value of farmhouse B was dramatically increased. Sensory evaluation showed that the color preference tended to decrease compared with the initial value. Only farmhouse B showed decreased overall acceptability. Moreover, farmhouse B had the highest storage temperature and lowest humidity. Therefore, our results showed that storage at a low temperature and high humidity was important for manufacturing high-quality dried persimmons.
        75.
        2017.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Aralia elata Seemann (AE) has long been used as a folk medicine for the treatment of various diseases including diabetes mellitus, anti-arthritic, and anti-gastric ulcer agent in Korea, Japan, and China. This study was performed to establish a simple and reliable HPLC/UV analytical method for determination of most active anti-hypertensive compound, a 3-O-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl hederagenin 28-O-β-D-xylopyranosyl(1→6)-β-D-glucopyranosylester (HE) for the standardization of the shoot extract of AE as a health functional food ingredient. The quantitative analytical method of HE was optimized by HPLC analysis using reverse-phase C18 column at 40°C with H2O and acetonitrile (70:30, v/v) as an isocratic mobile phase at a flow rate of 1.0 mL/min and detection wavelength of UV 205 nm. This HPLC/UV analytical method showed good specificity and high linearity in the tested range of 0.03125-2.0mg/ml with excellent coefficient of determination (R2) of 0.9999. The limit of detection and limit of quantification were 12.0 μg/mL and 36.5 μg/mL, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 0.2% and 0.1%, respectively. These results indicate that the established HPLC/UV analytical method is very simple, specific, precise, accurate, and reproducible and thus can be useful for the quantitative analysis of HE as a functional anti-hypertensive compound in AE extract.
        76.
        2017.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study the physicochemical properties and antioxidant capacities of ginger (Zingiber officinale Rosc) Jungkwa with different kinds of sweeteners were determined. Jungkwa made with different sugars (sugar, xylitol, honey or oligosaccharides) were compared in aspect of physiochemical properties, antioxidant activities, total phenolic contents and sensory evaluation. Moisture contents Jungkwa treated different kinds of oligosaccarides showed highest value, in the order of honey, xylitol and sugar. L* value of Jungkwa treated with xylitol was the highest, a* value of Jungkwa treated with honey, sugar Jungkwa were higher then others. Free sugar contents of Jungkwa treated with sugar showed the highest value in sucrose, glucose and galactose. Jungkwa with xylitol showed lowest value in all free sugar contents. Hardness and chewiness of Jungkwa treated with xylitol showed the highest value. The antioxidant activity measured by DPPH and ABTS radical scavenging activity and total penolic content were the highest in Jungkwa treated with honey, followed by Jungkwa treated with xylitol, oligosaccharides and sugar. Appearance and color of oligosaccarides and honey treated Jungkwa were preferred. In ginger taste, sweetness, chewiness were highest in sugar treated Jungkwa (not significant difference in treatments). As a result, honey treated Jungkwa has higher antioxidant activity and quality than other sugar treatments.
        77.
        2016.10 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        To examine the utilization possibility of defective coffee beans, non-defective and defective coffee bean were compared by means of its physiochemical properties and antioxidant capacities measured by DPPH radical scavenging activity, FRAP assay, total phenol contents, functional component (trigonelline, caffeine, chlorogenic acid) contents. After roasting process, pH and soluble solid contents of coffee extracts decreased; L* value decreased while a* and b* values increased. DPPH radical scavenging activities of defective green bean extracts were higher than that of non-defective green bean extracts. Immature green bean extract showed the highest radical scavenging activity. In FRAP assay, green bean extracts ranged from 15.28~21.80 mM TE which was higher than roasted bean extracts which showed 14.81~16.38 mM TE. Total phenol contents of green bean extracts ranged 191.06~256.25 mg% GAE which was higher than that of roasted bean extracts showed 161.91~173.44 mg% GAE. The contents of trigonelline, caffeine, chlorogenic acid in immature green bean extract were the highest, which showed 895.20 mg/L, 825.85 mg/L and 3,836.94 mg/L respectively. Each contents were decreased after roasting process. Results of this study suggest that defective coffee bean can be used as a functional food material.
        79.
        2015.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The influence of different roasting temperatures, times and extraction methods on the quality characteristics of Omija (Schizandra chinensis) seed oils was investigated. Roasted Omija seeds were divided into five groups based on roasting temperature-time conditions: no roasting (Raw) and roasting [R11: 150℃, 10 min, R12: 150℃, 20 min, R21: 250℃, 10 min, R22: 250℃, 20 min (R22)]. Oils from each of the raw and roasted Omija seeds were obtained by solvent (n-hexane) and press (machine) extraction. The L* values decreased, but the a* and b* values increased with increasing the roasting temperature and time. The L* values were lower in the press-extracted oils than in the solvent-extracted oils. The peroxide value (POV) of Omija seed oils decreased with increasing the roasting temperature-time values. The POV value was higher in the press-extracted oils than in the solvent-extracted oils. ABTS (2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) radical inhibition of Omija seed oils was higher in the solvent-extracted oils than in the press-extracted oils, but there were no significant differences between the two oils. The four major kinds of fatty acid methyl esters detected in Omija seed oils were methyl butyrate, methyl hexanoate, methyl arachidate, and methyl eicosanoate. In conclusion, Omija seed oils obtained by solvent extraction and at higher roasting temperature-time values were more effective antioxidants.
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