• The Journal of the Petrological Society of Korea
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• v.7 no.1
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• pp.1-14
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• 1998

Dangsanbong volcano, which is located on the coast of the western promontory of Cheju Island, occurs in such a regular pattern on the sequences which represent an excellent example of an eruptive cycle. The volcano comprises a horseshoe-shaped tuff cone and a younger nested cinder cone on the crater floor, which are overlain by a lava cap at the top of the cinder cone, and wide lava plateau in the moat between two cones and in the northern part. The volcanic sequences suggest volcanic processes that start with Surtseyan eruption, progress through Strombolian eruption and end with Hawaiian eruption, and then are followed by rock fall from sea cliff of the tuff cone and by air fall from another crater. It is thought that the eruptive environments of the tuff cone could be mainly emergent because the present cone is located on the coast, and standing body of sea water could play a great role. It is thought that the now emergent part of the tuff cone was costructed subaerially because there is no evidence of marine reworking. The emergent tuff cone is characterized by distinctive steam-explosivity that results primarily from a bulk interaction between rapidly ascending magma and external water. The sea water gets into the vent by flooding accross or through the top or breach of northern tephra cone. Dangsanbong tuff cone was constructed from Surtseyan eruption which went into with tephra finger jetting explosion in the early stage, late interspersed with continuous upruch activities, and from ultra-Surtseyan jetting explosions producting base surges in the last. When the enclosure of the vent by a long-lived tephra barrier would prevent the flooding and thus allow the vent to dry out, the phreatomagmatic activities ceased to transmit into magmatic activity of Strombolian eruption, which constructed a cinder cone on the crater floor of the tuff cone Strombolian eruption ceased when magma in the conduit gradually became depleted in gas. In the Dangsanbong volcano, the last magmatic activity was Hawaiian eruption which went into with foundation and effusion of basalt lava.

• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.777-783
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• 2018

The purpose of this study was to investigate the degree of tearing of the rubber when the spike of the syringe connector was connected to the bottle of the contrast medium composed of the rubber compound type and to investigate the presence of the synthetic rubber due to tearing and grinding and the size of the pulverized product when the pulverized matters rubber was detected. As a result, in the case of tearing degree, the front side of the first contact with the end of the syringe connector was torn more than the back side by about $3.14{\pm}0.04mm$, and the pulverized matters was detected on average 7 to 15 on the 10 contrast mediums. The average particle size was measured to be about $7.89{\pm}0.31{\mu}m$. In addition, it is necessary to develop a micro_filter type automatic injection system for blocking off the pulverized matters as well as additional experiments through various experiments and analysis methods, and it is considered that interest of related organizations will be needed in preparation of fatal accidents when pulverized matters is introduced.

• Journal of the Korean Society of Costume
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• v.16
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• pp.15-42
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• 1991

A nation's culture isn't consisted by the characteristics of the nation only, but it is greatly affected by the geographical features and natural conditions, and it could be also dominated by the continual effect through mutual contact on economic exchange or social problem and political interests with neighboring countries. It is a well known fact that the contact of culture between Korea and Mongolia established under the special political situation that Corea was invaded by Won. But more basically, the Nomad including Mongolia had influenced upon neighboring countries, therefore, our country was also greatly influenced on consisting of our own culture by them. Moreover. the fact that our language belongs to their language's category(mostly Tweigru and Mongolian language) proves that the origin of our culture was deeply related with Mongolia. Accordingly, we could not limit the cultural relation between Korea and Mongolia within a special era. But especially, since unification of China by Mongolia, Won which appeared as a new great nation had dominated Corea for one hundred years, and the Corea's costume culture had a point of conversion to the mongolian. Therefore, this study expects to comment upon the relations of costume between Corea and Mongolia from a view point of Corea's tribute and royal gifts gifts by Mongolia written on the reference literatures. 1) From the ancient times, between our country and Mongolia there has been a direct or indirect exchange caused by the people's movement or invasion due to very closed neighboring. The relations between Corea and Mongolia have started from the mongolia's requests of tribute for the reason why they helped Corea against the Keoran's invasion, and these relation had continued by King Kongmin's age. 2) Mongolia had plundered a tribute such as dress, cereals, horses, military supplies, soldiers, maiden and little girls etc. from Corea, and therefore, a great confusion occurred on political, economic and social fields. And since King Chungyoul of Corea got married with a Princess of Won, the Corea's position was placed as the Buma nation(nation of son in law) and then high class people of Corea preferred to follow the mongolian costume such as Byunbal (pigtail), Ho dress (mongolian dress), Rouges, Chockturi (a kind of formal cap) and Doturak pigtail ribbon, and some have been applied up to date. On the other hand, the custom of Corea had transmitted to the Mongolian nobility, they called it "Corea Yang(style)". 3) The costume of Corea could be divided into three different periods, the first is the period influenced by Tang and Song's regime, the second is affected by the Won's costume and the third is applying the Myung's regime in the end of Corea. The Mongolian dress was based on the Ho dress form and it has been developed through compounding artistic traditional fields and foreign customs in long history. And Mongolia is composed of various tribes, therefore, they have their own dress for each tribe. Our country and Mongolia had a similar dress form based on Ho dress and both used the Chacksukunggo (jacket with small sleeves and slacks) and Seon(line). And the ornaments of costume such as Chockturi, Doturak pigtail ribbon and Rouges had transmitted and fixed down as a traditional wedding garment, but the Rouges has been used by noble women from the ancient times in our country. Since a member of the Society of Korean Costume has visited Mongolia in August 1990 for the first time, I really recognized the neccesity of more detailed study on the costume relation between Korea and Mongolia, and I will proceed with the study on various fields of costume under cooperation of Institute of Oriental Academy of Mongolia.

• Applied Microscopy
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• v.31 no.4
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• pp.333-345
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• 2001

The mature sperms of three species of cephalopods (Octopus minar, Octopus ocellatus, Todarodes pacificus) were observed by electron microscopy. The results obtained are as follows: The sperm lengths of Octopus minor and Octopus ocellatus of octopods are long and they are about $390{\mu}m$ and $125\sim130{\mu}m$, respectively, but the sperm length of Todarodes pacificus is short and about $35{\mu}m$. The sperm of Octopus minor has a helical acrosome and a head bent a little like a banana while Octopus ocellatus of octopod has a twisted acrosome and a long rod-shaped head. A number of horizontal stripes are observed as a periodic structure in their subacrosome cavities and dense plugs are formed in the cavities of their heads. On the other hand, the acrosome of Todarodes pacificus is circular cap-shaped, and its head is long and oval. It is notable that two small cavities were observed in its basal acrosome. Juxtanuclear acrosomal materials of high electron density filled the subacrosomal cavity. In the middle piece of mature sperms of Octopus minor and Octopus ocellatus, the mitochondria form the mitochondrial sleeve, but the numbers of mitochondria differ between the species so that they are $11\sim12$ and $8\sim9$, respectively. Meanwhile, in the middle piece of mature sperms of Todarodes pacificus, the mitochondria are separated from the axoneme, forming a mitochondrial spur in which $10\sim13$ mitochondria and some electron dense materials concentrate. The axoneme of Octopus minor, Octopus ocellatus and Todarodes pacificus are of 9+2 type in common, surrounded by 9 coarse fibres. A number of glycogen were observed only in the axoneme of Todarodes pacificus. The coarse fibres were found as far as the main piece of sperm tail in Octopks minor and Todarodes pacificus, while to the end piece of sperm tail in Octopus ocellatus.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.491-501
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• 2022

Bentonite has been proposed as a buffer and backfill material for high-level radioactive waste repository. Under such repository environment conditions, bentonite is subjected to combined thermal, hydrological, mechanical, and chemical processes. This study evaluates the feasibility of applying X-ray CT technology on the characterization of bentonite under hydration conditions using a newly developed testing cell. The cylindrical cell is made of platic material, with a removable cap to place the sample, enabling to apply vertical pressure on the sample and to measure swelling pressure. The hydration test was carried out with a sample made of Gyeonju bentonite, with a dry density of 1.4 g/cm³, and a water content of 20%. The sample had a diameter of 27.5 mm and a height of 34 mm. During the test, water was injected at a constant pressure of 0.207 MPa, and lasted for 7 days. After one day of hydration, bentonite swelled and filled out the space inside the cell. Moreover, CT histograms showed how the hydration process induced an initial increase and later progressive decrease on the density of the sample. Detailed profiles of the mean CT value, CT standard deviation, and CT gradient provided more details on the hydration process of the sample and showed how the bottom and top regions exhibited a decrease on density while the middle region showed an increase, especially during the first two days of hydration. Later, the differences in CT values with respect to the initial state decreased, and were small at the end of testing. The formation and later reduction of cracks was also characterized through CT scanning.