• Applied Microscopy
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• v.30 no.4
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• pp.389-401
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• 2000

The mouse for identifying the histological changes of kidney were also divided into the two groups; treated with only $HgCl_2$ (4 mg/kg), the group treated with $HgCl_2$ and squalene (200 mg/kg). The $HgCl_2$ treated only one time at first day. The squalene treated two times a day (12 hours interval) for every day. Each groups were divided into the five groups; 6, 12, 24, 48 and 72 hours after treated $HgCl_2$ and squalene. Historical changes of the kidneys were investigated by electron microscope. The group with only $HgCl_2$ showed that the nuclear membrane was shrinked, the inner membrane (cristae) of the mitochondria were destructed, and ribosomes on the rough endoplasmic reticulum were lost. The group treated with $HgCl_2$ and Squalene showed that the nuclear membrane was more rounded, the cristae of the mitochondria were almost normal shape, and more ribosomes on the rough endoplasmic reticulum were attached. Therefore , we concluded that squalene has significantly protective effects in kidney to harmful $HgCl_2$.

• Journal of the Korean Geographical Society
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• v.1
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• pp.67-82
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• 1963

This paper examined the settlement and evolution of the Namdo Food Festival holding in Nakan folk village since 1994. The Namdo Food Festival is a representative event tourism in Chonnam which beautifully displays Nakan eup-sung's folk landscape and Namdo's traditional food, a prime tourist resource. Since 1994, the Namdo Food Festival has steadily evoloved in the scale aspects of the program budget, and the number of visitors participating in festiva. In addition, the period of the food festival was fixed for a week, early in October. The majority of visitors to the festival was from Kwangju. Moreover, visitors from other provinces have steadily increased, in particular visitors from Yeongnam province such as Pusas and Kyeongnam provinces have increased since 1996. In order to settle down and develop the Namdo Food Festival, the followings should be done change of the ownership from public to private sector, training of professional entertainers, development of programs which can reinforce historical aspects and placeness of Nakan folk village, adoption of management technoques for the local economic activities, and extension of linkage with tourists places around Nakan folk village, reflection of tourists interests and needs through a continuoua tourist's behaviour analysis.

• Journal of the Korean GEO-environmental Society
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• v.5 no.4
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• pp.33-45
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• 2004

In the present study, more systematic laboratory model tests under various conditions are carried out to investigate load-sharing characteristics among the granular pile and adjacent soils and bearing capacity characteristics with different pile lengths. Further to evaluate effects of both a loading area and a spacing of pile installation on the bearing capacity and bearing capacity characteristics of each pile in group, model test results are also analyzed for the purpose of an efficient design of granular compaction piles. From the analysis of the model test results, it is found that the ultimate capacity of granular compaction group piles increases with a decrease in the installation distance among granular piles. It is also found that the dominant failure mode of the granular compaction piles is bulging failure. It is further realized that the length of a granular pile could not significantly affect on the ultimate granular pile capacity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.11-19
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• 2015

We present the results of a multi-material numerical investigation of the propagation of a combustible gas mixture detonation in narrow metal tubes. We use an experimentally tuned one step Arrhenius chemical reaction and ideal gas equation of state (EOS) to describe stoichiometric $H_2-O_2$ and $C_2H_4-O_2$ detonations. The purely plastic deformations of copper and steel tubes are modeled using the Mie-Gruneisen EOS and Johnson-Cook strength model. To precisely track the interface motion between the detonating gas and the deforming wall, we use the hybrid particle level-sets within the ghost fluid framework. The calculated results are validated against the experimental data because the results explain the process of the generation and subsequent interaction of the expansion wave with the high-strain-rate deformation of the walls.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.449-458
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• 2010

The e-Learning quality assurance is a part of responsibility for education in latest information age, and should be understood as a basic direction for qualitative enhancement rather than quantifiable expansion. In such a context, this study sought to survey latest trends of e-Learning quality assurance activities deployed around overseas countries, so that it could give possible implications on how to plan and perform e-Learning quality assurance in Korea. So, this study focused on surveying actual conditions, coverage, target and useful indices of e-Learning quality assurance activities deployed by 9 institutions across 5 countries, and characterizing those activities across 5 countries. As a result, this study could find out its implications such as acquisition of various resources available for e-Learning, nationwide consolidation of e-Learning quality assurance activities, development of specialists in e-Learning quality assurance, and choice and focus for e-Learning quality assurance system. In other words, it was found that e-Learning quality assurance should be approached from nationwide standpoint in the interest of better educational quality, rather than from viewpoint of task.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.356-361
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• 2012

Recently, even though the researches on renewable energy like geothermal, wind, solar energy have been performed widely, its use-rate in total energy is still low. This study was carried out to investigate the performance of hybrid heating system, which consisted of solar collector of thermosyphon tube type and X-L pipe boiler. Especially, new type of solar collector was tried and compared with double tube type and, futhermore, performance and safety on X-L pipe boiler were investigated. As the results, efficiency of solar collector of thermosyphon tube type was higher 20.7% than that of double tube type, mainly due to its structural characteristics. It was also confirmed that temperature of special heat medium used X-L pipe boiler rose up about 20% rapidly in comparison with that of pure water.

• The Journal of the Petrological Society of Korea
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• v.28 no.4
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• pp.307-317
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• 2019

Petrological studies were performed on the Sanbangsan lava dome, located in the southwest of Jeju Island Volcanic Field. According to the lava ejection method, it is 'an internal primitive form' that is gradually pushed up and expanded by continuous magma injection from the bottom to the top of the vent and it corresponds to the 'low lava dome'. The rocks are partly plotted in the field of benmoreite, but mostly plotted in the field of trachyte of the Cox et al.(1979) classification diagram, and also mainly plotted in the field of trachyte of Le Maitre et al.(2002) and Zr/TiO₂-Nb/Y classification diagram. Therefore, the expression that described the rock of Sanbangsan lava dome as 'trachy-andesite' should be corrected to 'trachyte'. The volcanic rocks that consists in the Sanbangsan lava dome are trachyte containing normative quartz and shows differentiation trend in the range of 59.75-63.46 wt.% SiO₂.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.293-299
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• 2014

The bentonite, a buffer material, is essential for the deep geological disposal of HLW (high-level radioactive waste), and it is important to know its characteristic long-term evolution in the underground environment. With an assumption that the concentration of aqueous copper ions will increase if copper-coated materials on a metal canister are corroded, we examined some characteristic ion-exchanges and cation release phenomena occurring in the bentonite clay (montmorillonite) interacted with aqueous Cu cations. During the interaction between dissolved copper and bentonite, Na rather than Ca cations in the expandable clay were preferentially replaced by Cu ions in the experiment. In addition, the Cu-exchanged montmorillonite was characterized by an asymmetric X-ray diffracted pattern with relatively collapsed interlayers compared to the raw sample. These results indicate that the gradual change of the original bentonite property may occur in a underground disposal condition. We are going to further study the characteristic chemical and mineralogical changes of the bentonite buffer to be used for the disposal site by conducting additional experiments.

• Journal of the Korean Magnetics Society
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• v.3 no.1
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• pp.7-12
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• 1993

The effects of Mn, Cr or Co addItion on the magnetic properties of Fe-Ni Invar alloys were investigated. The composition range of the three additives is up to 5wt%. In the temperature range of room temperature-$250^{\circ}C$, the variation of specific magnetization with the addition of Mn, Cr or Co in the Fe-Ni alloys except for 5wt% Co shows the phenomenon characteristics of the Invar effect, viz., the specific magnetization decreases very abrubtly with the temperature and the dependence of temperature on the specific magnetization is in the mixed form of $T^{3/2}$ and $T^{2}$. In the room temperature, the amount of increase in the specific magnetization, Curie temperature and coercivity is in order of Co > Cr > Mn. In the case of 5wt% Co an anomalous phenomena were observed due to the occurrance of ferromagnetic $\alpha$ phase which reduces the invar effect.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.484-489
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• 2002

Hot-pressure sintered laminar composites with alumina/zirconia or mullite/zirconia as an outer layer and alumina/zircon (resulting in reaction-bonded mullite/zirconia during sintering) as an inner layer were fabricated by tape casting and lamination. Various forms of crack were observed in sintered laminar composites, these cracks included channel cracks in the outer layer, transverse cracks in the inner layer and interface cracks debonding interlayer. Based on detailed microscopic observations, the cracks were attributed to thermal expansion mismatch between the oxides consisting of the each layer. In particular, the interlayer and transverse cracks were confirmed in the laminates consisted of the mullite/zirconia system as the outer layers, however, those cracks were not observed in the alumina/zirconia system used. In addition, the crack propagation did not exhibit same behavior in the two kinds of outer layer when the indentation load was applied.