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        검색결과 728

        561.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        진세노사이드(인삼 사포닌)는 인삼의 대표적 약리성분 중의 하나로 생물학적 활성을 가진 배당체 화합물 이다. 이들 사포닌은 가수분해 되어 저분자화 되었을 때, 항주름 및 항산화, 항암 등에 높은 약리효능효과를 나타 낸다. 본 연구에서는 인삼 esculin 배지를 활용하여 β-glucosidase 활성을 가진 균주를 분리하였고 인삼 사포 닌 전환을 미생물을 이용하여 수행하였다. 본 균주들을 16S rRNA sequencing을 통하여 동정하여 본 결과 Stenotrophomonas rhizopilae strain GFC09로 확인되였다. 균주의 최적 활성 조건을 결정하기 위해 조효소 1 mM와 인삼사포닌 Rb1과 함께 배양한 후 생물학적 전환을 TLC, HPLC를 사용하여 확인하였다. 조효소에 의 한 인삼 사포닌 Rb1의 전환 경로는 다음과 같다. LB: RbNeobio R&D center, Gyeonggi-do 16954, Korea →Rd→FNeobio R&D center, Gyeonggi-do 16954, Korea→compound K, TSB: Rb1→Rd→ F2. 가수 분해된 생성된 물질은 NMR로 구조 동정하였다. 전환 산물의 효능 분석결과, 콜라겐 생성을 농도 의존적으로 증가시키는 것이 관찰되었다. 이에 본 연구에서는 ginsenoside F2와 compound K 함유 인삼 전환 산물의 주름 개선 소재로서 활용가능성을 확인하였다.
        562.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        본 논문에서는 양친매성물질인 C12-20 알킬글루코사이드, C14-22 알코올 및 베헤닐알코올로 구성된 액정 에멀젼을 제조하고 그 특성 및 in vitro 피부 투과 연구를 수행하였다. 액정 에멀젼의 배합비 실험 결과, C12-20 알킬글루코사이드 0.8%, C14-22 알코올 3.2% 및 베헤닐알코올 4%에서 선명한 액정 구조가 관찰되었다. 액정 에 멀젼과 비교군으로 O/W 에멀젼의 물리적 특성을 비교한 결과, 액정 에멀젼과 O/W 에멀젼의 점성은 각각 1871.26 ∼ 1.15 Pa⋅s 및 1768.69 ∼ 1.14 Pa⋅s이었으며, 전단응력은 액정 에멀젼은 190.45 ∼ 919.38 Pa, O/W 에멀젼은 178.68 ∼ 909.18 Pa로 측정되었다. 저장 탄성률은 액정 에멀젼은 4487.82 ∼ 8195.59 Pa, O/W 에멀젼은 3428.53 ∼ 9157.45 Pa, 탄성에 대한 점성의 비인 tan (delta) 값은, 액정 에멀젼은 0.23 ∼ 0.25, O/W 에멀젼은 0.43 ∼ 0.19로 나타났다. 경피 수분 함량 측정 결과, 액정 에멀젼은 O/W 에멀젼에 비하 여 사용 후 1 h부터 6 h까지 유의적으로 더 높은 피부 수분 함량을 나타냈으며, 경피 수분 손실에서는 30 min부터 4 h까지 유의적으로 수분 손실 억제 효과를 나타내었다. 글리시리직애씨드를 이용한 피부 투과 실험 결과, 24 h 동안 피부 투과량은 액정 에멀젼(64.58 μg/cm2), O/W 에멀젼(37.07 μg/cm2), 부틸렌글라이콜 용액(41.05 μg/cm2) 순으로 나타났고, 시간별 투과능 관찰 결과는 8 h 이후부터 액정 제형에서 피부 투과능이 증가하는 것으 로 나타났다. 결론적으로 액정 에멀젼은 피부의 보습 효과를 증진시킬 뿐만 아니라 기능성 소재의 효율적인 피부 전달체로서 응용 가능성이 있음을 시사한다.
        563.
        2015.11 서비스 종료(열람 제한)
        In this study, the malt residue was torrefied. The torrefaction of malt residue was investigated in a horizontal tubular reactor under nitrogen flow at a temperature ranging from 200 to 450℃. This study presents the effects of torrefaction on the basic characteristics of malt residue. The torrefied malt residue products were characterized in terms of their energy yield, ash content and volatile fraction. The gaseous products were also analyzed. It was found that the malt residue undergoes changes in their physical and chemical properties during torrefaction. Furthermore, the energy and mass yield were found to decrease with an increase in the torrefaction temperature, whereas the higher heating value increased gradually up to 450℃ on increasing the torrefaction temperature.
        564.
        2015.10 서비스 종료(열람 제한)
        The purpose of this research is to evaluate the mechanical characteristics of lathe scrap reinforced cementitious composites. For this purpose, the cementitious composites containing lathe scrap were made for 2mm width and 40mm length of lathe scrap, and then the mechanical characteristics such as compressive strength, splitting tensile strength, flexural strength, and elastic modulus of the cementitious composites were estimated. It was observed from the test results that splitting tensile strength and flexural strength of the cementitious composites were significantly improved than plain mortar but compressive strength and elastic modulus were only a slightly increased.
        565.
        2015.10 서비스 종료(열람 제한)
        The purpose of this research is to evaluate the standard deviation and coefficient of variation for flexural strength of lathe scrap reinforced cementitious composites. For this purpose, the cementitious composites containing lathe scrap were repeatedly made 5 times for water-binder ratio of 30%, 2mm width and 40mm length of lathe scrap, and then the standard deviation and coefficient of variation of the cementitious composites were estimated. It was observed from the test results that the standard deviation and coefficient of variation of the cementitious composites were slightly larger than plain mortar but did not matter much.
        566.
        2015.09 KCI 등재 서비스 종료(열람 제한)
        Soybean is one of the important food crop around the world. Especially in East Asia, it is the main ingredient for traditional food like soy sauce and soy paste. The double cropping system including soybean following onion, Chinese cabbage, and potato is widely adopted in Southern region of Korea. In this system, sowing date of second crop (soybean) can be delayed depending on first crops’ growth period and weather condition. When planting date is delayed it is known that soybean yield is declined because of shorter vegetative growth period and earlier flowering induced by warm temperature and changes in photoperiod. The objective of this study was to determine soybean growth and yield responses as plant populations at late planting date. Field experiment was conducted at Department of Functional Crop, National Institute of Crop Science, RDA located in Miryang, Gyeongsangnam-Do for two years (‘13-’14) in upland field with mid-late maturity cultivar Daewon. A split-plot block design was used with three replications. Main plots were three sowing dates from June 20 to July 20 with 15 days intervals, and subplots were 4 levels of planting densities. Data of maturity (R8) was recorded, yield components and yield were examined after harvesting. Experimental data were analyzed by using PROC GLM, and DMRT were used for mean comparison. Optimum planting population for maximizing soybean yield in late planting which compared with standard population. In mid-June planting, higher planting density causes increased plant height and decreased diameter which lead to higher risk of lodging, however, reduced growth period due to late planting alleviated this problem. Therefore higher seeding rates can provide protection against low seedling emergence caused by late planting in this region.
        567.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        정밀안전진단시 콘크리트 강도를 추정하기 위한 방법으로 강도추정식을 이용한 방법이 많이 사용되며, 이용되는 추정식은 외국에서 이미 제안된 식이 대부분이고, 적용되는 추정식에 따라서 추정강도의 차이가 심하게 발생하며, 전반적으로 강도추정의 신뢰도가 낮아져 정밀안전진단 결과의 신뢰성에도 상당한 영향을 미친다. 이런 문제점은 일부 국한된 부분에서 발생하게 되어 다수의 실험을 통하여 신뢰도를 높일 수 있다. 본 논문은 이와 같은 필요성을 포괄하기 위해 실내압축강도와 관련된 신뢰도 평가식을 제안하였다. 확률론적 기법을 이용하여 신뢰도 평가식의 유용성을 검증하였으며 실내압축강도와 추정압축강도의 추이 그래프를 비교하였다. 비교결과, 본 연구에서 제시된 신뢰도 평가식의 유용성을 확인하였다.
        568.
        2015.05 KCI 등재 서비스 종료(열람 제한)
        본 논문은 강섬유 대신 철근집합체를 사용하여 초고강도 섬유보강 콘크리트 부재의 최대하중 이후 연성거동을 유도하는 것을 목적으로 한다. 강섬유와 철근집합체의 조합을 가진 직사각형 콘크리트 보에 대한 휨거동 실험을 수행하였다. 강섬유의 혼입률은 0%, 0.7%, 1%, 1.5%, 2%이고, 연성거동을 유도하기 위한 종방향 철근 집합체의 철근비는 0.0036, 0.016, 0.028 그리고 0.036이다. 이러한 실험 요소의 조합으로 15개의 초고강도 콘크리트보가 제작되었다. 강섬유 뿐만 아니라 종방향의 철근 집합체도 초고강도 콘크리트보의 연성거동을 유도하는데 효과를 가지고 있다. 강섬유 혼입률 0.7%와 철근비 0.028인 철근집합체를 사용할 경우 가장 경제적인 조합임을 볼 수 있다. 하중과 처짐관계, 콘크리트 응력의 변화 및 균열양상 등이 좁은 간격을 가진 작은 직경의 종방향 철근 집합체의 유용성을 나타내고 있다.
        569.
        2015.05 서비스 종료(열람 제한)
        Torrefaction is a treatment which serves to improve the properties of biomass in relation to thermochemical processing techniques for energy generation. In this study, the torrefaction of sewage sludge, which is a non-lignocellulosic waste was investigated in a horizontal tubular reactor under nitrogen flow at temperature ranging from 150-600℃. The torrefied sewage sludge products were characterized in terms of their energy yield, ash content and volatile fraction. The energy and mass yields decreased with an increase in the torrefaction temperature. The pelletization and the combustion characteristics of the torrefied sewage sludge was studied in isothermal and non-isothermal conditions.
        570.
        2015.04 서비스 종료(열람 제한)
        The purpose of this research is to investigate characteristics of cementitious composites containing lathe scrap to use it as a alternative materials of steel fiber. For this purpose, the cementitious composites containing lathe scraps were made according to 5mm, 10mm, and 20mm in lengths for their widths of 2mm and 4mm, respectively. It was observed from the test result that the cementitious composites containing lathe scraps were most largely increased than plain mortar in the compressive and flexural strengths when its width is 2mm and its length is 5 to 10mm.
        571.
        2015.04 서비스 종료(열람 제한)
        This study intends to suggest a methodology of normalization of inspected highway bridges damage. The noticeable point is to normalize the amount of the inspected accumulated damage on bridges according to a normalizing scale. The normalized damages represent such a characteristics of the bridges. With the normalized damage data, a future maintenance cost can be estimated that can be applicable for determining long-term maintenance strategy.
        572.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        The photocatalytic decomposition characteristics of toluene, acetone, and methyl mercaptan (MM) by UV reactor installed with TiO2-coated perforated plane were studied. The removal efficiency of single toluene, acetone, and MM vapor was increased with increasing oxygen concentration, but decreased with increasing inlet concentration. Elimination capacity of single toluene, acetone, and MM vapor was obtained to be 628 g/m3․day, 1,041 g/m3․day, and 2,158 g/m3․day, respectively. Also, the photocatalytic decomposition of binary vapor consisted of toluene and acetone, toluene and MM, acetone and MM were observed. Elimination capacity of toluene mixed with acetone, toluene mixed with MM, acetone mixed with toluene, acetone mixed with MM, MM mixed with toluene, and MM mixed with acetone was 327 g/m3․day, 512 g/m3․day, 128 g/m3․ day, 266 g/m3․day, 785 g/m3․day and 883 g/m3․day, respectively. The inhibitory effect of acetone was higher than MM in photocatalytic decomposition of toluene, the inhibitory effect of toluene was higher than MM photocatalytic decomposition of acetone, and the inhibitory effect of toluene was higher than acetone in photocatalytic decomposition of MM.
        573.
        2015.03 KCI 등재 서비스 종료(열람 제한)
        The feasibility of PS-D2EHPA/TBP beads prepared by immobilizing two extractants D2EHPA and TBP in polysulfone to remove Sr(II) from aqueous solution was investigated in batch system. Batch experiments were carried out to study equilibrium isotherms, kinetics, and thermodynamics. Equilibrium data were fitted using Langmuir, Freundlich, Redlich– Peterson, and Dubinin-Radushkevich equation models at temperatures of 298 K, 313 K, and 328 K. The removal capacity of Sr(II) by PS-D2EHPA/TBP beads obtained from Langmuir model was 2.41 mg/g at 298 K. The experimental data were well represented by pseudo-second-order model. The removal process of Sr(II) by PS-D2EHPA/TBP beads prepared in this study was found to be feasible, endothermic, and spontaneous.
        574.
        2015.01 KCI 등재 서비스 종료(열람 제한)
        The solid-phase extractant PS-D2EHPA/TBP was prepared by immobilizing two extractants D2EHPA and TBP in polysulfone (PS). The prepared PS-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal of Cu(II) from aqueous solution was investigated in batch system. The experiment data were obeyed the pseudo-second-order kinetic model. Equilibrium data were well fitted by Langmuir model and the removal capacity of Cu(II) by solid extractant PS-D2EHPA/TBP obtained from Langmuir model was 3.11 mg/g at 288 K. The removal capacity of Cu(II) was increased according to increasing pH from 2 to 6, but the removal capacity was decreased below pH 3 remarkably.
        575.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        In this study, the photocatalytic decomposition characteristics of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed methyl mercaptan (MM) by UV reactor installed with TiO2-coated perforated plate were studied. The photocatalytic decomposition rate of single toluene, toluene mixed with benzene, toluene mixed with acetone, and toluene mixed with MM fitted well on Langmuir-Hinshelwood (L-H) kinetics equation. The maximum elimination capacity was obtained to be 628 g/m3·d for single toluene, 499 g/m3·d for toluene mixed with benzene, 318 g/m3·d for toluene mixed with acetone, and 513 g/m3·d for toluene mixed with MM, respectively. The negative effect in photocatalytic decomposition of toluene are found to be in the order of acetone>benzene>MM.
        576.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 우리 식생활과 가장 밀접한 관계가 있는 고추(청고추, 홍고추)를 유기 및 관행으로 재배하여 품질특성과 기능성성분 함량을 비교 분석하였다. 유기 및 관행재배 고추의 품질특성은 pH, 가용성고형물 함량, 경도 및 색도를 분석하였다. 그 결과 유기 및 관행재배 고추의 가용성고형물이 유기재배에서 2.6~10% 높은 경향을 나타내었으나 경도는 관행재배에서 높게 나타났다. 기능성 성분은 클로로필 함량, ASTA 값, 총페놀성화합물 함량 및 SEM을 통한 세포조직을 검토하여 비교분석 하였다. 청고추의 경우 유기재배에서 관행재배에 비해 녹색도(-a value)값이 더 높게 나타났으며 chlorophyll 함량 또한 a, b, total 값이 전반적으로 높게 나타났다. 홍고추의 경우 유기재배에서 붉은색의 정도를 나타내는 ASTA 값이 28% 더 높게 나타났다. 또한 항산화효과가 있는 것으로 알려진 총페놀성화합물 함량은 청고추와 홍고추에서 모두 유기재배가 관행재배 보다 더 높은 것으로 조사되었다. 따라서 고추 유기재배의 경우 고추 색깔에 관계없이 품질특성 측면에서 색택이 더 우수하고 기능성 측면에서 또한 더 우수한 것으로 사료된다.
        577.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        Abstract PS-D2EHPA beads were prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polysulfone (PSf). The removal experiments of Cu(II) and Pb(II) by the prepared PS-D2EHPA beads were conducted batchwise. The removal efficiency of Cu(II) and Pb(II) by PS-D2EHPA beads was increased with increasing pH of solution. The removal rate of Cu(II) and Pb(II) was well described by the pseudo-second-order kinetic model. The maximum removal capacity of Cu(II) and Pb(II) obtained from Langmuir isotherm were 2.58 mg/g and 12.63 mg/g, respectively. External mass transfer coefficients for the removal of Cu(II) and Pb(II) by PS-D2EHPA beads were obtained 0.61×10-2∼ 5.87×10-2 /min and 1.55×10-2∼8.53×10-2 /min, respectively and diffusion coefficients were obtained 1.32×10-4∼ 3.98×10-4 cm2/min and 1.80×10-4∼2.28×10-4 cm2/min, respectively.
        578.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        This paper proposes an underwater localization algorithm using probabilistic object recognition. It is organized as follows; 1) recognizing artificial objects using imaging sonar, and 2) localizing the recognized objects and the vehicle using EKF(Extended Kalman Filter) based SLAM. For this purpose, we develop artificial landmarks to be recognized even under the unstable sonar images induced by noise. Moreover, a probabilistic recognition framework is proposed. In this way, the distance and bearing of the recognized artificial landmarks are acquired to perform the localization of the underwater vehicle. Using the recognized objects, EKF-based SLAM is carried out and results in a path of the underwater vehicle and the location of landmarks. The proposed localization algorithm is verified by experiments in a basin.
        579.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        Acoustic signal is crucial for the autonomous navigation of underwater vehicles. For this purpose, this paper presents a method of acoustic source localization. The proposed method is based on the probabilistic estimation of time delay of acoustic signals received by two hydrophones. Using Bayesian update process, the proposed method can provide reliable estimation of direction angle of the acoustic source. The acquired direction information is used to estimate the location of the acoustic source. By accumulating direction information from various vehicle locations, the acoustic source localization is achieved using extended Kalman filter. The proposed method can provide a reliable estimation of the direction and location of the acoustic source, even under for a noisy acoustic signal. Experimental results demonstrate the performance of the proposed acoustic source localization method in a real sea environment.
        580.
        2014.11 서비스 종료(열람 제한)
        Anaerobic Baffled Reactor(ABR)는 혐기성 소화 공정 중 하나로 주로 중소규모의 폐수처리에 사용되며 반응조 내부에 설치된 격벽(Baffle)에 의해 산생성과 메탄생성의 공간적 분리가 뚜렷하고, 일정 수준의 고액분리 효과를 기대할 수 있으며, 비교적 짧은 HRT(Hydraulic Retention Time)와 긴 SRT(Solids Retention Time)를 유지할 수 있다는 장점이 있다. 본 연구에서는 ABR 공정을 이용하여 하수처리공정에서 발생하는 1차 슬러지를 안정화시키는 과정에서 메탄생성을 억제하고 산생성을 최대화하여 고농도의 유기산(Volatile Fatty Acid, VFA)을 생산하고자 하였다. 이때 생산되는 유기산은 후단 탈질반응조의 외부 탄소원으로 이용되어 후탈질 공정으로 유입되는 고농도의 NO3-N을 제거하도록 하였다. 최적 설계 인자 도출을 위하여 ABR 형태의 산발효조와 탈질반응조의 HRT, SRT 및 슬러지 반송과 폐기량이 VFA 생성 및 탈질에 미치는 영향을 살펴보았다. 실험실 규모의 연구결과 HRT 2, 4, 6 및 8일에서 ABR공정을 통한 1차 슬러지 유입 SCOD대비 VFA 생성율은 각각 107±121, 35±87, -82±9 및 -82±12%로 HRT 2일에서 가장 높은 산 생성율을 나타내었으며, HRT 6일 및 8일에서는 긴 체류시간으로 인해 생성된 유기산의 상당량이 메탄으로 전환되면서 VFA 생성율이 저하되는 결과를 보였다. 또한 각 조건에서 생산되는 VFA를 탈질반응조의 유입탄소원으로 이용하였을 때, 유입되는 SCOD의 70% 이상이 탈질에 사용되었으며, NO3-N의 제거율은 평균 82±11% 수준의 탈질효율을 확인하였다.