• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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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.

• Journal of Environmental Science International
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• v.16 no.10
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.E
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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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• v.11 no.1
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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.

• Journal of Korea Foundry Society
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• v.14 no.5
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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.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.111-118
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• 2013

The objective of this study was to determine the biological activities of Sorglum bicolor extracts. Organic fractions, including n-Hexane, EtOAc, and n-BuOH fractions were obtained from the methanol extract of Sorglum bicolor M.. In DPPH radical scavenging activity, $SC_{50}$ values of methanol extract and EtOAc fraction were exhibited $0.66{\pm}0.26{\mu}g/mL$ and $1.03{\pm}0.02{\mu}g/mL$, respectively. Contents of total polyphenol and flavonoids in EtOAc fraction, which were much higher than those of other fractions, were 58.12 mg/g and 4.79 mg/g respectively. Also, effects of reducing power was strongly showed in EtOAc fraction. ${\alpha}$-Glucosidase and ${\alpha}$-amlyase inhibition activities were showed the higher effect in D.W. fraction ($2.83{\mu}g/mL$, $36.64{\mu}g/mL$). In MTT assay in the AGS, HT29 and HCT116 cell lines were significantly higher in the n-BuOH fraction than in the other fractions at $50{\mu}g/mL$ concentration of extracts.

• Journal of the Korean School Mathematics Society
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• v.23 no.2
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• pp.203-222
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• 2020

Because the role of the teacher is important for the education to actualize the goals of the curriculum, the interest about the teacher's knowledges has been addressed as an important research topic. Among them, the pedagogical content knowledge is the knowledge that can emphasize the professionalism of the teacher. In this study, I analyzed the elementary pre-service teachers' the problem solving strategies that they imagined the methods that elementary school students can think about fraction division. Pre-service teachers who participated in this study were completed all of the mathematics education courses in the pre-service teachers' education courses. The research was conducted using the four type-problems of fraction division. The results showed that elementary pre-service teachers responded in the order of equal sharing problem-measurement division-partitive division-context of determination of a unit rate problem. They presented significant responses not only with typical algorithms but also with pictures or expressions. On the basis of this research, we have to take an interest in the necessity of sharing and recognizing various methods of fraction division in pre-service teachers education.

• Journal of Science Education
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• v.46 no.1
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• pp.109-120
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• 2022

Fraction division is the content that is important but difficult to learn because it includes the process of finding a numerical expression in the real-world context, the process of making a context that matches a numerical expression, how to solve division, and the justification of standard algorithm. This study analyzes the word problems and problem solving methods about fraction division which elementary pre-service teachers represented. Pre-service teachers have more difficulty in making word problem where the dividend is less than the divisor and they also show typical errors in making the word problems. There were differences in the methods presented according to the contexts of division in problem solving. Through this study, it is necessary to rethink the teaching methods for fraction division instruction in the curriculum for pre-service teachers and analyze the formation process of 'knowledge for content and teaching' because of the differences in responses between grades.

• Atmosphere
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• v.29 no.4
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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.

• Journal of Educational Research in Mathematics
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• v.10 no.1
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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.