• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.741-746
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• 2005

To investigate the basic information and the possibility of ACE-inhibitory peptides for antihypertension materials, goat's caisin (CN) was hydrolyzed by various proteolytic enzymes and ACE-inhibitory peptides were separated and purified. ACE-inhibition ratios of enzymatic hydrolysates of goat's CN and various characteristics of ACE-inhibitory peptides were determined. ACE-inhibition ratios of goat's CN hydrolysates were shown the highest with 87.84% by pepsin for 48 h. By Sephadex G-25 gel chromatograms, Fraction 3 from goat's CN hydrolysates by pepsin for 48 h was confirmed the highest ACE-inhibition activity. Fraction 3 g and Fraction 3 gh from peptic hydrolysates by RP-HPLC to first and second purification were the highest in ACE-inhibition activity, respectively. The most abundant amino acid was leucine (18.83%) in Fraction 3 gh of ACE-inhibitory peptides after second purification. Amino acid sequence analysis of Fraction 3 gh of ACE-inhibitory peptides was shown that the Ala-Tyr-Phe-Tyr, Pro-Tyr-Tyr and Tyr-Leu. IC$_{50}$ calibrated in peptic hydrolysates at 48 h, Fraction 3, Fraction 3 g and Fraction 3 gh from goat's CN hydrolysates by pepsin for 48 h were 29.89, 3.07, 1.85 and 0.87 g/ml, respectively. Based on the results of this experiment, goat's CN hydrolysates by pepsin were shown to have ACE-inhibitory activity.

• 한국환경과학회지
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• 제16권10호
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• pp.1197-1202
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• 2007

Adsorption experiments of binary mixed gases composed of acetone/methylethylketone (MEK), MEK/benzene, MEK/toluene, and benzene/toluene were carried out on activated carbon fixed-bed. The variations of equilibrium adsorption capacity according to type and fraction of binary gas were investigated. In case of binary gases composed of acetone/MEK and benzene/toluene, equilibrium adsorption capacities of MEK and toluene were increased according to the increase of fraction of MEK and toluene, but equilibrium adsorption capacities of acetone and benzene were decreased. In case of binary gases composed of MEK/benzene and MEK/toluene, equilibrium adsorption capacities of benzene and toluene were increased according to the increase of fraction of benzene and toluene, but equilibrium adsorption capacities of MEK was decreased.

• 한국주조공학회지
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• 제14권5호
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• pp.438-446
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• 1994

The effect of various thermomechanical treatments on the structure and rheological behaviour of Al-6.2wt%Si alloy in its solidification range were investigated using a Searle type high temperature viscometer. During continuous cooling, the viscosity increases gradually with increasing fraction of solidified alloy, until a critical fraction of solidified alloy is reached above which the viscosity sharply increases. The viscosity of the slurry, at a given volume fraction wolid, decreased with increasing shear rate. The size and morphology of primary solid particles during stirring is influenced strongly by shear rates, cooling rates, volume fraction and stirring time of solid. Morphological changes during stirring as a function of solid volume fractions, shear rate and processing time were also reported. In this study, the size of primary solid particles in these alloys consistently increases and the it`s aspect ratio decrease with the increase in fraction solid and decrease in shear rate. Crystal morphology changes from rosette type to spheroid type with the increase in shear rate and solid fraction.

• Journal of Korean Society for Atmospheric Environment
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• 제16권E호
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• pp.47-57
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• 2000

This study focuses on the investigation of the effects of windspeed and particle size on the dust control characteristics inside a test dome built in the Port of Inchon to reduce the fugitive dust originating from the handling of animal feed stuff in the open pile area. The flow field inside the test dome and the trajectories of the particles were calculated using a commercial CFD code, FLUENT, assuming that the animal feed stuff handling activity took place inside the test dome. It was found from the simulation results that high windspeed and small particle size give rise to the increase in both the escaped fraction and the suspended fraction of the particles emitted from the animal feed stuff handing activity. Here, high escaped fraction represents the high possibility of fugitive dust problem outside the test dome, whereas high suspended fraction means the high possibility of severe dust pollution inside the test dome. Ore simulation results clearly show that the existing test dome was not designed properly to meet the proposed goal, low escaped fraction and low suspended fraction. Hence, we suggest the need of an efficient ventilation system inside the dome to control the dust.

• Preventive Nutrition and Food Science
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• 제11권1호
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• pp.6-9
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• 2006

This study was conducted to evaluate the antioxidant activity of each fraction from Sedum sarmentosum. Antioxidant activity of each fraction was measured using the DPPH radical assay, the ferric thiocyanate (FTC) method, and thiobarbituric acid (TBA) method. The antioxidant activities were then compared with that of BHT(synthetic antioxidant). The ethyl acetate and butanol fractions were found to have significant DPPH radical scavenging activity, with scavenging potencies showing 90.61 % and 87.02%, respectively. Total phenolic compound contents, determined according to the Folin-Denis method, were found to be in the order of ethyl acetate>butanol>ethanol>chloroform>aqueous fraction. From the results, we have been able to establish a positive correlation between the antioxidant activity and the total phenolic compound content of the sample. The antioxidant activity in a linoleic acid system was measured using the ferric thiocyanate (FTC) method and thiobarbituric acid (TBA) method. The ethyl acetate fraction had the highest antioxidant activity among the tested fractions. On the basis of these results, the ethyl acetate fraction provided equivalent or higher antioxidant activity as compared to BHT. These results suggest that Sedum sarmentosum is a potentially useful antioxidant for foods, cosmetics, and medicine.

• 한국학교수학회논문집
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• 제23권2호
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• pp.203-222
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• 2020

교육과정이 의도하는 목적을 달성하는데 교사의 역할은 중요하기 때문에 교사가 갖추어야 할 지식에 대한 연구가 중요하게 다루어져 왔다. 이 중에서 '교수학적 내용 지식'은 교사의 전문성을 부각시킬 수 있는 지식으로, 본 연구에서는 분수 나눗셈에 대해 초등학생들이 제시할 수 있을 것으로 생각되는 문제해결 방법에 대한 초등 예비교사들의 지식을 분석하였다. 본 연구에 참여한 예비교사들은 대학 교육과정 중 수학과 교육 필수 강좌를 모두 마친 상태였으며, 이들을 대상으로 분수 나눗셈의 4가지 유형에 대해 조사연구를 실시하였다. 연구 결과, 초등 예비교사들은 균등 분배 문제-포함제-등분제-단위 비율 결정 상황의 순으로 빈도수를 나타내었으며, 전형적인 알고리즘뿐만이 아니라, 그림을 이용하거나 식을 이용한 경우에서도 의미 있는 반응들을 제시하였다. 이를 바탕으로 예비교사 교육기간에 분수 나눗셈의 여러 가지 해결 방법을 서로 공유하면서 이에 대한 지식을 갖출 필요성을 제안하였다.

• 한국자원식물학회지
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• 제26권1호
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• pp.111-118
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• 2013

본 연구에서는 붉은장목수수(Sorglum Bicolor M.) MeOH 추출물과 분획물들의 다양한 생리활성을 비교하기 위하여 항산화(DPPH assay, 환원력, 총 페놀 및 플라보노이드 함량), 항당뇨(${\alpha}$-Glucosidase 저해활성 및 ${\alpha}$-Amlyase 저해활성), 항암(MTT assay) 활성을 관찰 하였다. 항산화활성의 경우 EtOAc fraction이 높은 총 페놀과 플라보노이드 함량을 나타내었으며, DPPH assay와 reducing power 결과 역시 EtOAc fraction과 MeOH fraction이 positive control로 사용한 ${\alpha}$-tocopherol보다 우수한 활성을 나타냈다. ${\alpha}$-Glucosidase, ${\alpha}$-amlyase 저해능 평가 결과 D.W. fraction이 가장 높은 활성을 보였으며 n-BuOH fraction과 MeOH extract도 활성을 나타내었다. 암세포인 AGS, HT29, HCT116세포주에 대한 세포독성 연구인 MTT assay에서는 EtOAc, n-BuOH, D.W. fraction을 처리한 처리구에서 독성을 보였으며 이중 n-BuOH fraction이 모든 세포주에서 농도 의존적으로 세포독성을 가지는 것을 확인할 수 있었다. 연구결과 붉은장목수수의 추출물 EtOAc fraction의 항산화활성, D.W. fraction의 항당뇨활성, n-BuOH fraction의 암세포에 대한 독성과 관련된 화합물의 분리 및 구조규명에 관한 연구가 필요 할 것으로 사료되어지며, normal cell에 대한 MTT assay를 진행하여 항암활성에 관한 연구를 진행하여 붉은장목수수 추출물을 이용한 다양한 건강기능식품과 의약품 개발을 통해 건강 증진과 질병으로부터 보호 받을 수 있을 것으로 기대한다.

• 과학교육연구지
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• 제46권1호
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• pp.109-120
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• 2022

분수 나눗셈에서는 실세계 상황에서 식을 찾는 과정과 역으로 식에 맞는 상황을 만드는 과정, 나눗셈식을 해결하는 방법과 표준 알고리즘의 정당화 과정 등이 중요하면서도 이해하기 어려운 학습 내용이다. 본 연구에서는 예비교사들의 분수 나눗셈식에 맞는 문장제 만들기와 문장제 해결에 이용한 방법을 분석하였다. 초등 예비교사들은 피제수가 제수보다 작은 분수 나눗셈에서 그 반대인 경우보다 문장제 만들기에 어려움을 가지고 있었고, 문장제 만들기에서도 전형적인 오류를 나타내었다. 문장제 해결에서는 문제 상황에 따라 이용한 방법에 차이가 나타났다. 본 연구를 통해 예비교사 교육과정에서 분수 나눗셈 지도에 관한 지도 방법의 재고와 학년 간 반응 결과의 차이를 고려할 때 예비교사들의 '교수와 내용에 관한 지식'의 형성 과정에 관한 분석이 이루어질 필요가 있다.

• 대기
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• 제29권4호
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• pp.381-390
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• 2019

This study investigates the impacts of urban land-use fraction and temperature advection on the urban heat island intensity over the Seoul metropolitan area using the UM (Unified Model) with the MORUSES (Met Office Reading Urban Surface Exchange Scheme) during the heat wave over the region from 2 to 8, August 2016. Two simulations are performed with two different land-use type, the urban (urban simulation) and the urban surfaces replaced with grass (rural simulation), in order to calculate the urban heat island intensity defined as the 1.5-m temperature difference between the urban and the rural simulations. The land-use type for the urban simulation is obtained from Korea Ministry of Environment (2007) land-use data after it is converted into the types used in the UM. It is found that the urban heat island intensity over high urban-fraction regions in the metropolitan area is as large as 1℃ in daytime and 3.2℃ in nighttime, i.e., the effects of urban heat island is much larger for night than day. It is also found that the magnitude of urban heat island intensity increases linearly with urban land-use fraction. Spatially, the estimated the urban heat island intensities are systematically larger in the downwind regions of the metropolitan area than in the upwind area due to the effects of temperature advection. Results of this study indicate that urban surface fraction in the city area and temperature advection play a key role in determining the spatial distribution and magnitude of urban heat island intensity.

• 대한수학교육학회지:수학교육학연구
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• 제10권1호
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• pp.103-113
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• 2000

A case study was conducted to investigate the understandings of the subject matter knowledge and pedagogical content knowledge held by 63 elementary preservice teachers in dealing with the division by a fraction. The study results showed that, in terms of the subject matter knowledge, the preservice teachers did not have a conceptual understanding of the division by a fraction and, in terms of the pedagogical content knowledge, they depended heavily on algorithms without a conceptual understanding of the meaning of the division by a fraction.