• Journal of the Korean Magnetics Society
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• v.26 no.2
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• pp.39-44
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• 2016

Determination of the structural, electronic, and magnetic properties of the magnetically doped bismuth-telluride alloys are drawing lots of interest in the fields of the thermoelectric application as well as the research on magnetic interaction and topological insulator. In this study, we performed the first-principles electronic structure calculations within the density functional theory for the Gd doped bismuth-tellurides in order to study its magnetic properties and magnetic phase stability. All-electron FLAPW (full-potential linearized augmented plane-wave) method is employed and the exchange correlation potentials of electrons are treated within the generalized gradient approximation. In order to describe the localized f-electrons of Gd properly, the Hubbard +U term and the spin-orbit coupling of the valence electrons are included in the second variational way. The results show that while the Gd bulk prefers a ferromagnetic phase, the total energy differences between the ferromagnetic and the antiferromagnetic phases of the Gd doped bismuth-telluride alloys are about ~1meV/Gd, indicating that the stable magnetic phase may be changed sensitively depending on the structural change such as defects or strains.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.409-419
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• 2014

In accordance with the global age, countries in the world try to dedicate to collaboration among them through ODA (Official Development Assistance), in order to solve the-rich-get-richer and the poor-get-poorer problems among countries, to develop the developing countries' economies, and to improve their level of social welfare. Also, Korea is so active in ODA as a member of OECD, even if it is in the initial process. Nowadays, in Korea, the importance of ODA in the field of port has been brought into relief. Accordingly, the paper intends to analyze the dilemma structure of port ODA from the perspectives both of new institutionalism and Samaritan's dilemma game, and it tries to seek the improvements of ODA institutions to create effective outcomes based on the analysis. Through the analysis, dilemma structure was identified regarding the institutions of port ODA. And the results of the analysis suggested the improvements of port ODA institutions including strengthening of on-the-spot aid system, establishment of payoffs system for inducing recipient countries' efforts, and institutionalization of reliable threat. It would contribute to develop the theoretical model of ODA analysis and create effective outcomes of ODA in the field of ports.

• Journal of Korean Home Economics Education Association
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• v.26 no.4
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• pp.35-50
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• 2014

This study is a discussion about specific directions and strategies for development of subsequent curriculum of practical arts(technology ome economics) based on two issues ; developing curriculum which is 'connecting elementary-secondary course' and 'based on key competence'. Specific Study is as in the following. First, in the aspect of home economics, this study explored the meaning of connection between elementary-secondary courses, and in the process of curriculum development, we explored implicit problems through strategies that come out from elementary-secondary courses. Second, we search what the key competence is in terms of home economics, and the meaning of developing curriculum based on the key competence. For this, we examine the meaning of development of subject matters curriculum based on key competence and the conditions and tasks for developing curriculum for home economics based on key competence. Third, on the basis of discussion we explore the way to realize these two issues, already mentioned, into development of subsequent curriculum for home economics. For this, this study examines the academic interaction between home economics of elementary and secondary courses unifying the names of the subject, systematic understanding about development of curriculum based on key competence, finding strategies for appealing the subject, and practical instances. Through this study, we expect more active interaction between home economics from elementary and secondary courses and academic discussion for development of curriculum.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.315-326
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• 2015

Temporal and spatial variations of surface water temperature in Jinju Bay for the period of 2010~2011 were studied using the data from temperature monitoring buoys deployed at 17 stations in the south coast of Korea. Water temperature shows the maximum late in January and the minimum early in August. Seasonal variation of water temperatures at the north part of the bay is smaller than the middle and the south. In summer, the lowest and the highest of maximum water temperature are distributed around Jijok Channel which is located at the south of the bay. The fluctuations of water temperatures at Noryang and Daebang Channel are smaller than others because of vertical mixing caused by passage of strong tidal currents. Wind and strong currents affect on the stratification of the surface water layer near Daebang Channel. High temperatures come in frequently around the north area when eastward constant flows appear at neap tide as blowing westerly in the springtime at Noryang Channel. Spectral analyses of temperature records show significant peaks at 7~20 day periods at Noryang Channel, 7~20 day and semidiurnal at the west coast of Changsun Island and Jijok Channel and 7~20 day and diurnal at the middle of the bay. Temperature fluctuation at Noryang Channel shows high coherence and has leading phase with those at other stations in the bay. However, the phase of temperature fluctuation at Noryang Channel falls behind that at Daebang Channel. Daebang Channel has an influence on the temperature fluctuation only at the west and middle part of the bay. Cross-correlation analyses for the temperature fluctuation show that Jinju Bay could be classified into six areas; Noryang Channel, the area of convergence and divergence at the north, Daebang Channel, the west coast of Changsun Island, the mixing area at the middle of the bay and the south inside of the bay, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.185-196
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• 1991

The rice culture, the most representative farming in humid regions of East Asia, have been playing a decisive role in supplying finance and staple food of the nations. This situation must be formed with exchange of techniques and interests in the matter betwen China, Korea and Japan. Especially Korea was obligated to playa bridge role because of geographical conditions, thereby the situations of agriculture were repeatedly reclaimed, and recovered by changes of cultures during external aggression, and internal disturbances. Thus, it is obvious that development of rice culture and its techniques was being undaunted in Korea. Nevertheless, in history of Korea, the documents of the government on chronicles of the dynasty were plentiful, while they were very poor in countryside and rural communities, so that it is very hard to search the transition process of rice culture and its techniques. Finally, the faming books that were begun editing from the early Chosun dynasty are here divided chronically and examined, and also the interrelationships are compared and discussed here. The objectives of this study were to discuss the following questions？ How were the dryfarming techniques, introduced from the ancient China by the end of Koryo dynasty, established to fit for our situations？ What were the basis for reestablishment of the techniques with originality？ How were they continued and changed through the internal and external wars in the Chosun dynasty？ What were suggested from these continuously results by the end of the Chosun dynasty?

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.5
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• pp.436-442
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• 2008

Graphite material has been recognized as a very competitive candidate for reflector, moderator, and structural material for very high temperature reactor (VHTR). Since VHTR is operated up to $900-950^{\circ}C$, small amount of impurity may accelerate the oxidation and degradation of carbon graphite, which results in increased porosity and lowered fracture toughness. In this study, ultrasonic wave propagation properties were investigated for both as-received and degradated material, and the feasibility of ultrasonic testing (UT) was estimated based on the result of ultrasonic property measurements. The ultrasonic properties of carbon graphite were half, more than 5 times, and 1/3 for velocity, attenuation, and signal-to-noise (S/N) ratio respectively. Degradation reduces the ultrasonic velocity slightly by 100 m/s, however the attenuation is about 2 times of as-receive state. The results of probability of detection (POD) estimation based on S/N ratio for side-drilled-hole (SDHs) of which depths were less than 100 mm were merely affected by oxidation and degradation. This result suggests that UT would be reliable method for nondestructive testing of carbon graphite material of which thickness is not over 100 mm. In accordance with the result produced by commercial automated ultrasonic testing (AUT) system, human error of ultrasonic testing is barely expected for the material of which thickness is not over 80 mm.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.1
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• pp.55-61
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• 2015

When a radiation detector is applied to the measurement of the radioactivity of high-level of radioactive materials or the rapid response to the nuclear accident, several collimators with the different inner radii should be prepared according to the level of dose rate. This makes the in-situ measurement impractical, because of the heavy weight of the collimator. In this study, an IRIS collimator was developed so as to have a function of controlling the inner radius, with the same method used in optical camera, to vary the attenuation ratio of radiation. The shutter was made to have the double tungsten layers with different phase angles to prevent the radiation from penetrating owing to the mechanical tolerance. The performance evaluation through the MCNP code was conducted by calculating the attenuation ratio according to the inner radius of the collimator. The attenuation ratio was marked on the outer scale ring of the collimator. It is expected that when a radiation detector with the IRIS collimator is used for the in-situ measurement, it can change the attenuation ratio of the incident photon to the detector without replacing the collimator.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.3
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• pp.343-347
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• 2018

We synthesized 1, 2-hexanediol galactoside (HD-Gal) from HD using Escherichia coli (E. coli) ${\beta}-galactosidase$ (${\beta}-gal$), in which the reaction is generally called as transgalactosylation (reverse hydrolysis). In this study, we investigated how much HD-Gal and HD had a cytotoxic effect on HaCaT cell, in order to compare HD-Gal with HD in terms of the cytotoxicity of human skin cell. Cell proliferation assay and phase-contrast microscope observation were used for investigating the cytotoxicity. As a result, HD-Gal had not cytotoxic effect on HaCaT cell in the concentration range from 42.2 to 211 mM. In addition, when we observed the cells using microscopy, there was no change in the cell morphology. Meanwhile, when 42.2 mM and 84.4 mM HD were treated on HaCaT cell, we did not observe the cytotoxicity; however, when 168.8 mM and 211 mM HD were on HaCaT cell, HD had a higher cytotoxic effect on HaCaT cell. In addition, when HD was treated on the cells regardless of the concentration of HD, there were obvious changes in cell morphology and cell number. It was expected hopefully that HD-Gal would be applicable as a substitute for HD as a less toxic preservative in views of safety, health, and well-being.

• Journal of Korea Port Economic Association
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• v.31 no.3
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• pp.141-153
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• 2015

This paper is an attempt to analyze the comparative advantage of Busan Port to China. For this, we use the market comparative advantage index, which is a version of the revealed comparative advantage index. The market comparative advantage index (MCA) uses trade patterns to identify the sectors in which a region has a comparative advantage, in this case by comparing Busan Port's trade profile with the world average (China). The indices are calculated at the commodity level of the HS four-digit classification. The export data used in this study are obtained from the Korea International Trade Association. Exports to China accounted for almost one third of Korean exports in 2014. There are, however, structural differences among the main export items of Busan Port. This paper, therefore, employs MCA indices to reveal the behaviors of the ten main export items, which are "HS3920-other plates/sheets/film/foil of plastics," "HS7606-aluminum plates/sheets/strip," "HS8479-unspecified machines/medical appliances," "HS8486-machines for semiconductor devices or wafers," "HS8529-parts for transmission apparatus for television," "HS8703-motor vehicles for the transport of persons," "HS8708-parts of motor vehicles," "HS9001-optical fibers," and "HS9013-liquid crystal devices." The study shows that export competitiveness of nine items increases, the exception being HS8703. However, China's import ratios of seven of the nine items for which the MCA indices go up are on the decrease, which means that it would be hard to expand the export market for these seven items, despite the higher MCA indices. Since the shares of the port's total exports to China of HS3907, HS8486, HS8529, HS9001, and HS9013 in total exports to China increase together with China's import ratio decreasing, these items may have promising export markets. MCA increases of HS7606 and HS8479 are attributable to China's lower import ratio, rather than a higher export share, so higher MCA indices do not guarantee higher export competitiveness for these items.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.680-692
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• 2000

An assessment instrument dealing with secondary students' views on the nature of science was developed in this study. The features in aspects of the nature of science are generally accepted as characterizing the scientific enterprise and we have focused on are: 1) the purposes of the scientific enterprise, 2) the nature of scientific enquiry, 3) the nature and status of scientific knowledge, and 4) the nature and functioning of the scientific community. The questionnaire is made of three sections; that is, "Scientific Question", "Experiment", and "Belief". The Scientific Questions probe was designed to examine the ways in which learners mark out science as a particular domain, and particularly the types of questions that they think are open to scientific investigation. The Experiment probe was designed to throw light on the ways in which learners may think about theories and their relationship to evidence in a range of contexts. A related aim concerns the sorts of activities that learners consider to be experiments, and their reasons for this. The Belief probe was designed to see whether students are able to articulate the grounds for their acceptance of a proposition and, if they are, to explore the nature of these grounds. The reliability of the instrument developed in this study was found to be 0.86.