• Geotechnical Engineering
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• v.13 no.5
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• pp.5-18
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• 1997

Anisotropy in strength and deformation characteristics of isotropically consolidated sande prepared by pluviating through air was studied by plane strain compression tests. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. The strains for direction of bmazimum principal stress and direction of minimum principal strews were measured continuously from $10^{-6}\; to 10^{-2}$. The following results were obtained for all sands. The behaviour at strains leas than about 0.001% was elastic and isotropic regardless of the angle $\delta\; of\; the\;\sigma$ direction relative to the bedding plane. However, the sands became gradually more anisotropic as the strain increased to the extent exceeding the elastic limit. The peak strength was noticeably anisotropic with a similar trend. Thus, the angle of internal friction $\phi\; decreased \;as\;\delta$ decreased from $90^{\circ}$, and the ratio of the smallest to largest values of was between 0.82 and 0.90. The l has a minimum at $\delta=0^{\circ}~30^{\circ}$ depending on the hypes of sand. The residual strength became isotropic again.

• Polymer(Korea)
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• v.32 no.5
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• pp.470-477
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• 2008

Core shell binder of organic/organic pair that has two different properties within a particle were prepared by a step emulsion polymerization of methacrylate (MMA), styrene (St), ethyl acrylate (EA), butyl acrylate (BA), and 2-HEMA by using an water soluble initiator(APS) in the presence of an anionic surfactant (SDBS). Unwoven tensile strength of the core shell binder after processing and measuring the PSt/PMMA/2-HEM core shell with the binder is a value represents the highest was $10.75\;kg_f$/2.5cm, elongation measurements PEA/PBA core shell binder showed the highest value was 120.00%. In conclusion, using the core shell binders were able to control the mechanical properties such as tensile strength and elongation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.46-53
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• 2017

This paper shows a length of wirecutter using an analysis based on Rotorcraft's control input and taxiing speed. In case of selecting an inappropriate length of wirecutter which applies to rotorcraft for safety, this causes a collision between blade and wirecuter, or an accident by wire. We review the control input which was used in development stage, and establish the conditions of control input which are needed in taxiing. Based on these conditions, we review the collision possibility between blade and wirecutter through analysis in case of 20, 40, 60 kts taxiing speed. Following, this result is verified by comparison with that of a simulation test in rotorcarft. Finally, in case of high collision possibility, we presented the downsize length to avoid the collision and increment of non-protective area in flight, simultaneously.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.299-304
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• 2005

There have been many efforts to use anionic hydrogels as oral protein delivery carriers due to their pH-responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid-co-methacryloxyethyl glucoside) [P(MAA-co-MEG)] hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation $M_t/M_{\infty}=kt^n$ was used to calculate the exponent, n, describing the Fickian or non-Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation-controlled in the swelling medium of pH 7.0 that was higher than the $pK_a$ of the gels. Experimental results of time-dependent swelling behavior of the gels were analyzed with several mathematical models. Using ATR-FTIR spectroscopy, the effect of ionization of the carboxylic acid groups in the polymer networks on the water transport mechanism was investigated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1352-1370
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• 2010

In this paper, we investigated the shadow area of radio programs which are currently being broadcast via FM 102.5 MHz in Jeollabuk-do consisting of 6 cities and 8-guns. The field strength data of FM 102.5 MHz was used with criterion of shadow area. As a result, the field strength of the eastern mountainous area in Jeollabuk-do was very low. We also measured, compared and analyzed the field strength of 102.5 MHz(TBN-Jeonju), 100.7 MHz(KBS) and 99.1 MHz (MBC) in Jeollabuk-do. Based on the field strength data, we tried to find what correlation exists and how much influence is between difference of antenna output power and solution of shadow area. In result, enhancement of antenna output power is not solution in terms of reducing the shadow Area of 102.5 MHz(TBN-Jeonju). In addition, we measured, compared and analyzed the field strength of 102.5 MHz(TBN-Jeonju) and 106.9 MHz(EBS). In fact, the relay stations with 104.1 MHz, 104.9 MHz, 105.3 MHz and 107.5 MHz of EBS FM has a number of FM relay stations in the eastern mountainous area of Jeollabuk-do. As a result, we confirmed that EBS almost did not have shadow area in the eastern mountainous area of Jeollabuk-do based on the field strength data. As in the case of EBS and KBS, we suggest installing TBN-Jeonju FM relay station with the best solution to reducing the shadow area to extend the audible range of TBN-Jeonju.

• The Korean Journal of Mycology
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• v.12 no.4
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• pp.183-188
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• 1984

This paper was concerned with the investigation on the species of fungi detected in indoor environments. Mycological survey on the wall of buildings and houses in Seoul was performed from December 26, 1983 to February 11, 1984. The collected fungi with the sterilized cotton rod were caltivated and isolated in the Potato-Detrose Agar medium with chloramphenicol. The fungi detected in hospital were Cladosporium sp., Penicillium sp., Alternaria sp., Chaetomium sp. and others. The fungi detected in household were Penicillium sp., Alternaria sp., Aspergillus sp., Cladosporium sp., Rhizopus sp., Trichoderma sp. and others. The kitchen of household was more contaminated by fungi than the living room and others. In hospital, it was much contaminated by the same species of the aboves on the wall of lobby and refectory. As the above results were recognized, the higher humidity and the more poor ventilation, the more species and amount of fungi were contaminated. Further studies on the identification of pathogenic fungi should be continued. The proper regulation for the hygienic maintenance of indoor environment in household, hospital and other public buildings should be recommended as well.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.586-592
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• 2015

This study was performed to determine optimum approaches for control of microorganisms in school refectories and kitchens. A reduction of more than 5.0 log CFU/mL was noted for Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Streptococcus mutans after treatment with 5 ppm ozone water for 60 s. Treatment of different vegetables with ozone water for 5 min showed bactericidal effects with 2-4 log reduction of viable cell number; the bactericidal effects differed according to the kinds of vegetables. The viable cell number on kitchen apparatus and tableware was not detected by ozone water treatment for 60 s. In addition, the count of the bacteria floating in the air in refectories and kitchens decreased 2.0 log CFU/1,000 L air to 0-1 CFU/1,000 L air on treatment with 45 ppm ozone gas for 12 hr. Therefore, ozone water and ozone gas may be good candidates as antimicrobial agents that can be used to improve sanitary conditions in school refectories and kitchens.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.107-116
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• 2014

The purpose of this study is to verify the applicability of concept mapping in the process of planning social welfare program based on community network. Concept mapping is a kind of decision-making method that structuralized complex ideas and presented visually. Already, concept mapping is widely utilized in counseling, nursing and public health area to plan and evaluation their program and service. For recent, effectiveness of concept mapping has been reported. Concept mapping is a effective decision-making method that they recognize outcome gap between service provider and client, reach the outcome's consensus in counseling and nursing, medical area. In this study, we conceptualized 3rd year outcomes of Community Impact Project that was supported from Busan Chest using concept mapping. This CI project intervenes children and youth who lives in Buk-gu, Busan. Concept mapping has six stages-preparation, collecting ideas, structuring statements, representing statement, interpreting the results of the analysis, applying the results. We followed these steps. The participants were working at social welfare organizations, total 11 persons. We obtained 60 statements and analyzed using multidimensional scaling. we collected 5 clusters, cluster 1 'awareness and attitude change of children and youth', cluster 2 'social system change of children and youth', cluster 3 'friendly community formation', cluster 4 'community people change', cluster 5 'service provider change'. As a result, among total 5 clusters formed, 'awareness and attitude change of children and youth' came to the strongest outcomes. When concept mapping was applied to the program planning, the consensus of the opinion came easily in the decision-making process, and the participants were empowered. In addition, clear conceptualization on each element of the program planning was made.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.565-576
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• 2011

This study was conducted to describe forest stand characteristics of the habitats of Allium victorialis var. platyphyllum population from the ecological analysis of classification of vegetation types, importance values, species diversity, interspecific association and community similarity in Ulleung Island and Mt. Hambaek, in which investigated by 48 plots ($10m{\times}10m$). The vegetation studied was classified into 1 community group, 2 communities, 2 groups and 3 subgroups for a species unit and divided by 5 units for a vegetation unit. In the Fagus engleriana group (vegetation unit 1, 2 and 3), importance value of A. victorialis var. platyphyllum in herb layer showed relatively higher value than other units. Importance value of A. victorialis var. platyphyllum in herb layer had higher value. In the analysis of interspecific association, most of the species associated positively to A. victorialis var. platyphyllum belonged to habitat features of valley area and sub-alpine zone. Therefore, it was considered that the growing environment of A. victorialis var. platyphyllum population was closely correlated to soil moisture and air humidity.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.446-458
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• 2018

The media is not just a means of conveying social reality, but is also a political economic subject that restructures social reality. The perceptions and attitudes of the people who read the news can be influenced by the content and direction of the media. Therefore, it is very important to understand and discuss the characteristics of news coverage produced by media. In the case of issues closely related to economic benefits rather than general socio-economic issues, more objective arguments and confirmation of facts are required. In this study, we tried to understand how real estate policy, which is one of the major political and economic issues of S. Korean society, is covered in the media. After analyzing media coverage, we concluded that it was somewhat unreasonable to look at facts about real estate policy objectively and make realistic alternatives, because the framework and attitudes expressed in the articles varied by newspaper.