• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.28-35
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• 2016

The in-situ thermal response test for the design of a ground heat exchanger of geothermal heat pumps have difficulty in predicting the outlet temperature according to the variation of conditions due to the expense and time. This paper suggests a 3-D CFD analysis method to predict the heat transfer performance of vertical type ground heat exchanger, which is mostly used in national, and the outlet temperature and the slope of two in-situ thermal response tests were compared to test the proposed CFD reliability. The results of CFD analysis showed that the outlet temperature was predicted to within $0.5^{\circ}C$ of the actual value and the slope was predicted to within 1.6%. The reliability of the CFD analysis method was confirmed using this process, and the outlet temperature prediction of the two in-situ thermal response tests was obtained by changing ${\pm}20%$ of the flow rate and the effective thermal conductivity conditions, respectively. The results of CFD analysis showed that the outlet temperature of Case 1 was 28.0 (-20%) and $29.6^{\circ}C$ (+20%) for the flow rate variation and $29.6^{\circ}C$ (-20%) and $28.0^{\circ}C$ (+20%) for the effective thermal conductivity variation, and the outlet temperature of Case 2 was 28.4 (-20%) and $29.8^{\circ}C$ (+20%) for the flow rate variation and $29.7^{\circ}C$(-20%) and $28.4^{\circ}C$(+20%) for the effective thermal conductivity variation.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.100-108
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• 2020

20th century music has been recognized as disconnected. Some criticized that it is not music. This controversy has been continued over decades in music history. This study applied Darwin's evolutionary theory to John Cage's 4'33", the most popular music in 20th century and tried to prove musical continuity embedded in it. 4'33" has always been a subject of controversy because it has no sound. However, the study found out that 4'33" has the common musical factor, the rest. 4'33" can be interpreted as the variation of the rest in evolutionary view. The rest has undergone a variety of variations in form and meaning since the beginning of the musical notation and was suitable for a new musical environment changed in 20th century. In the evolutionary view, 4'33" is evolved music, not disconnected.

• The Journal of the Korea Contents Association
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• v.20 no.7
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• pp.223-232
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• 2020

This study aims to examine the trend of research articles for the age of youth at 20s during 10 years through topic modeling and keyword network analysis. In results, 'incomes', 'program', 'business start-up', and 'culture' were selected as main keywords, and the research articles were classified into six topics, which were employment support services, values, unstable life, government support policies, religious views, and business start-up support services. Additionally, we found the youth at 20s had higher rate of efficacy for digital technology, pursued efficient consumption of digital information, showed meaningful and athetical patterns of consumption, tried to search for their identity, and showed realistic action in daily. Finally, we raised some questions for value gap among aging groups, inbalance of regional development, and income inequality and suggested long-term youth policies to solve fundamental problems of youth at 20s.

• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.777-786
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• 2003

The purpose of this study was to compare the perception of men's lower body shape in the 60s with that in the 20s. On hundred and seven men in the 60s and 178 men in the 20s participated in the survey and measurements. The results were as follows : 1. It was perceived that men in the 60s had broader girth but lighter weight than men in the 20s. The research revealed that men in the 60s was more satisfied with their lower body shape than men in the 20s. 2. It was also found that the ideal size of men in the 60s was broader in the girth of their waist and hip, shorter in their height, and lighter in their weight compared to men in the 20s. 3. It showed a difference in the satisfaction with their body shape between men in the 60s and the 20s. The satisfaction with their lower body shape of men in the 60s was more affected by their perception than by their real measured size. On the other hand, the satisfaction of men in the 20s was affected by their perception as much as by their measured size. 4. If we look at the perception and satisfaction in relation with their body types, we found that there was a difference in the girth of their waist, abdomen, hip, and weight depending on their body types. And men in the 20s showed greater differences in their perception and satisfaction depending on their body types, compared to men in the 60s. 5. The measured size of men in the 20s had greater differences depending on their body types than that of men in the 60s. On the contrary, the ideal size of men in the 60s had greater differences than that of men in the 20s.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1182-1185
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• 2002

The objective of this study was to investigate the effect of long light regime (20 h light and 4 h dark, 20L:4D) and short light regime (4 h light and 20 h dark, 4L:20D) on egg production and egg characteristics of laying geese. Thirty-six laying birds, 4 replicates of 3 birds per treatment were allotted to three light regimes, i.e., 20L:4D, 4L:20D, and natural light (NAT) from March 7 to June 20. Results showed that the geese in 20L:4D consumed 54 g less feed per goose daily and laid 17.5 less eggs per goose (p<0.05) comparing to those in 4L:20D. The number of days from initiation of light treatment till cease of laying was 22 days shorter (p<0.05) in 20L:4D comparing to that in NAT. Five geese (41.7%) in 4L:20D kept laying by the end of applying light regime. Weight and surface area of the eggs in 4L:20D were greater (p<0.05) comparing to those in the other two light regimes. It is concluded that the period of egg production in goose could be manipulated by light regime in the ways such as using short light regime of 4 h light daily to prolong egg production through summer and using long light regime of 20 h light daily to induce cease of egg production.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.475-478
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• 2003

Bacillus subtilis K-20 chunggukjang is widely used in making soy sauces and bean pastes which are Korean traditional fermented foods. Bacillus subtilis K-20 chunggukjang was cultured, and fermented at $40^{\circ}C$ and 90% humidity for 96 hr after homogenizing with garlic, garlic and onion, and garlic, onion, and ginger. As a result, a product with pizza flavor and taste was obtained from Bacillus subtilis K-20. This product could be used as a functional food to promote immunity.

• Journal of Adhesion and Interface
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• v.13 no.4
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• pp.156-162
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• 2012

Polyurethane (PU)/organoclay nanocomposites were prepared by mixing UV curable urethane acrylate oligomer with organoclay, and a subsequent curing by UV irradiation. As organoclays, commercially available Cloisite 20A (C20A) and acrylsilane modified C20A were used. XRD and TEM analyses revealed that the UV cured PU/clay nanocomposites formed intercalated nanocomposites, and acrylsilane modified C20A are dispersed more finely than unmodified C20A in PU matrix. DMTA, pencil hardness and adhesion test onto PET substrate showed that the clay nanolayers induced an increase in the properties, and the enhancement in the properties was more pronounced in the PU/acrylsilane modified C20A nanocomposites than in the PU/unmodified C20A nanocomposites. It was also observed that the PU/surface modified clay nanocomposites showed remarkably lower shrinkage upon UV curing than the unfilled PU. The nanocomposites showed excellent optical transparency but lower gloss as compared to unfilled PU.

• Journal of the Korean Society of Costume
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• v.51 no.7
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• pp.111-121
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• 2001

The purpose of this study was to investigate the historical changes, and analyze functions and characteristics of western men's underclothes in the second half of the 20C. This study will examine how the social backgrounds influenced on the changes of the functions of men's underclothes and how the changes of outer garments were reflected on underclothes in the second half of the 20C. In the early, the second half of the 20C, underwears of functions was continued to cleanliness and comforts. In the later of the 20C, underwears came to be seen as expressing male sexual power when it became body-conscious. By the changes of outer garments. underclothes changed the same size of proportion. In the late 1960's, the turtleneck type of shirts were copied by outer garments, and we understand that underwear can influence on outer garments. The ruffles of the 18th century reappeared in the 1960's. This reactionism of the late 20C tells us about the relation between social environments and underwear. So the social backgrounds influenced on the formativeness of men's underclothes. We understand that underwear can influence on outer garments and outer garments can influence on underwear, too. The important characteristics of the second half of the 20C were the remarkable resemblance of some styles to those of the Past and the occasional blurring of the distinction between underwear and outerwear.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.143-150
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• 2018

Oil-in-water emulsion was prepared using cinnamoyl surfactants as emulsifiers. Cinnamoyl surfactants used in the present study were polyoxyethylene (20) sorbitan monolaurate-cinnamic acid conjugate (TW20CA), polyoxyethylene (20) cetyl ether-cinnamic acid conjugate (CE20CA), and polyoxyethylene(20) oleyl ether-cinnamic acid conjugate (OE20CA). The emulsion stabilized with TW20CA was the most stable, possibly because the polyoxyethylene segment of TW20CA would sterically stabilize the oil droplets effectively. In vivo UV protecting efficacy of surfactant and emulsion was investigated by determining the minimum amount of UV light (MAUL) to induce a black point on the back of hairless mice (HRM2). The mean MAUL of PARSOL, OE20CA, and emulsion stabilized with TW20CA was $1046.5mJ/cm^2$, $1163mJ/cm^2$, and $1308.5mJ/cm^2$, respectively. The high UV-protecting efficacy of the emulsion could be ascribed to not only the UV-absorbing property of cinnamoyl group but also the UV-scattering property of the oil droplets.

• Journal of Practical Agriculture & Fisheries Research
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• v.5 no.1
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• pp.20-27
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• 2003

This experiment was carried out to develop an acclimatization system of tissue cultured seedling in Zantedeschia spp. There was not different in percentage of leaf emergence by the media compost of acclimatization but tuber was enlarged in sand(50%)+peatmoss(50%) treatment after 6 months growth. The optimum time for the acclimatizantion of Zantedeschia spp. was from the 20th of March to 20th of April. During this time, rate of acclimatization reached over 90 percentage. However on the 20th of august, acclimatization was low to 64-70.4 percentage. Size of tuber was enlarged in planting on the 20th of March. The weight of tuber was better in 10×10cm density of planting than others.