• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.482-490
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• 2006

Deep caries in primary molars without early intervention frequently induce a pulpal disease and consequent abscess lesion in surrounding tissue. Especially in many furcation radiolucent lesions of primary molars, accessory canals in furcation areas of primary molars play an important role in theses pathological progress. Although the studies of these communication canals in furcation area of human permanent molar well documented, there has been little research showing their existence in primary molar. For the purpose of understanding the morphological characteristics of accessory canals at furcation areas of primary molars and examining its frequency and patency, 52 specimen teeth were observed under the scanning electro-microscope and tested with dye penetration under vacuum pressure, and obtained the results as follows : 1. In SEM study, the frequency of accessory foramina viewed from the external and internal furcation area was 60% and 35% respectively. Likewise the diameter of the accessory canals was within the range of $11{\sim}107{\mu}m$ and $12{\sim}62{\mu}m$ respectively. 2. The frequency of patent accessory canals evidenced by the dye penetrated under the vacuum suction at furca areas in primary molars was 50% among the 20 specimen teeth tested.

• Applied Microscopy
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• v.30 no.1
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• pp.89-100
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• 2000

We observed the salivary ducts of two species of snails, Achatina fulica and Incilaria fruhstoferi with an electron microscope, and obtained the following results. The intralobular and interlobular ducts of Achatina fulica assume the forms of round or ellipsoidal doughnuts. The boundaries between the endothelial cells are not clear. It is also found that the cytoplasm of the endothelial cells consists of the membrane infolded in interdigital form, and there are well -developed microvilli at the apical portion of the cytoplasm. On the other hand, the intralobular and interlobular ducts of Incilaria fruhtoferi consist of the irregular simple columnar epithelia. The high electron dense cytoplasm is filled with the irregular round granules. The microvilli at the apical portion of the cytoplasm are not so well-developed as those in Achatina fulica. In the salivary duct of Achatina fulica, the lumen has narrow and long tubular structure. The boundaries between the endothelial cells are not clear. The cytoplasm is full of many vacuoles and electron lucent granules. At the apical portion of the cytoplasm, lots of short and thin microvilli are found. The salivary duct of Incilaria fruhstorferi is wider ($65\times250{\mu}m$ in diameter) than that of Achatina fulica, and consists of endothelial cells of the same structures. At the apical portion of those endothelial cells, a lot of junction apparatus such as desmosomes are observed. The vessels in the salivary ducts of Achatina fulica and Incilaria fruhstoferi are observed mainly in the connective tissues between the salivary glands. The endothelial cell of the vessel has the irregular structure and looks dark due to the high electron density. These cells protrude their filopodia and phagocytosize foreign bodies.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.247.2-247.2
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• 2014

플라즈마 전파 속도와 전자 온도를 조사하기 위해 ICCD카메라(Intensified Charge-Coupled Device Camera, 이하 ICCD)를 이용하여 대기압 저온 플라즈마제트의 방전 이미지를 촬영하였다. 사용된 플라즈마 제트 장치는 유리관 안에 주사기 바늘형 전극이 들어있는 형태이다. 전극의 내경은 1.3 mm, 외경은 1.8 mm, 총 길이는 39.0 mm이며 재질은 스테인레스강이다. 유리관의 내경은 2.0 mm, 외경은 2.4 mm, 총 길이는 80.0 mm이다. 입력 전압은 3.0 kV이며 구동 주파수는 40 kHz이다. 아르곤과 질소의 혼합가스 비율은 각각 100:1, 98:2, 95:5을 사용하였으며 총 가스유량은 400 sccm이다. 각각의 비율별로 군속도는 267 km/s, 305 km/s, 313 km/s이며 이온 음향 속도는 1.16 km/s, 1.24 km/s, 1.25 km/s이고, 전자 온도는 0.55 eV, 0.63 eV, 0.65 eV로 관찰되었다.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.21-42
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• 2015

This paper shows the case of the evolution of Korean e-Government services in the theoretical lens of Actor-Network Theory and Structuration Theory. It presents how human actors (i.e. presidents and the central administrations) and non-human actors (i.e. law, standards, and relay systems) have established as the one network together, and how this network affects the evolution of Korean e-Government services. This case demonstrates in public sector can adopt not only Actor-Network Theory, but also Structuration Theory to explain both micro and macro contexts. The practical implications are given especially for the developing countries in pursuing the rapid development process of e-Government services.

• Journal of the Korean Society for information Management
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• v.21 no.3
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• pp.227-250
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• 2004

In order to design effective electronic records management systems, it is viable to consider both traditional principles of records management, proven to be effective, and the characteristics of digital information. ISO 15489, an international standard for records management, is acknowledged as the most useful guidelines for this goal. The present study extracted basic principles of electronic records management from its provisions of 7 functional steps. It then compared the principles to system requirements of three system design criterion, developed by Department of Defense(U.S.A.) Public Records Office(Britain). and European Union respectively. Common requirements, included in all three criterion. were then searched in the Korean standard of developing automated systems for records centers. Finally, suggestions were made to develop a Korean standard for electronic records management system, elaborating from the core requirements of the system found by the present study.

• The Korean Journal of Zoology
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• v.23 no.4
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• pp.219-228
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• 1980

The ultrastructures of the granular glands in the asiatic land salamander (Hynobius leechi) skin were observed by means of electron microsope The results were as follows; 1. The granular gland of the asiatic land salamander skin consisted of a body of gland and a duct. The body of the granular gland consisted of the glandular epithelial cells and the myoepithelial cells. The duct of the granular gland consisted of the keratinocytes. 2. The glandular epithelial cells in the asiatic land salamander skin were divided into the dark cell and the light cells in accordance with the electron density of the cytoplasm. 3. The secretory granules of the granular glands were round or oval in form and were divided into the various granules, showing the secretory granules showing weak electron density had the parts showing strong electron density near the granular membrane. 4. It is supposed that showing the different electron densities of the granules in a glandular epithelial cell is due to different mature stages and to different level of water absorption, and the chemical components of the granules showing different electron densities are identical.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1287-1292
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• 2018

In case of fire, the information related with the fire need to be provided to fire fighters in order to extinguish the fire efficiently. However, existing fire detection systems have the problem not to provide the data of the fire to fire fighters visually. In this paper, we propose the fire spot system using a cloud server to solve this problem. In the proposed system, the sensors installed in a building collect the gas and temperature data and store them into the cloud database using a wireless network. For fire fighters in the field, the details and history of the fire spot are displayed visually on top of the blue print retrieved from the cloud database using a smart device.

• Applied Microscopy
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• v.33 no.4
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• pp.315-323
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• 2003

The fine structural characteristics of the spinnerets and spigots of the silk producing apparatus in the adult funnel-web spider, Agelena limbata, were analysed with the light and scanning electron microscopes. Silk producing apparatus of this spider was composed of three pairs of spinnerets (anterior, median, posterior) and four different types of spigots-ampullates, tubuliforms, pyriforms and aciniforms. By the examination of their ultrastructural characteristics, it has been revealed that each spigot on the spinnerets are connected through the typical silk gland within abdominal cavity. Among the three pairs of spinnerets, the posterior pairs were highly elongated and has most characteristic features. Two pairs of large ampullates were connected to anterior spinneret and another two pairs of small ampullates to median spinnerets. Spigots of the tubuliforms were observed only in female and were connected both of median and posterior spinnerets respectively. While spigots of the pyriforms were connected on the anterior spinnerets but aciniforms on both of median and posterior spinnerets respectively.

• Geophysics and Geophysical Exploration
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• v.3 no.2
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• pp.48-52
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• 2000

We have calculated and analyzed the electromagnetic responses of buried conductive pipes due to a horizontal magnetic dipole source on the pound using a three-dimensional (3-D) finite element method to provide useful guidelines for designing electromagnetic pipe locator and for field operation of the system. For single buried pipe, the horizontal component and the horizontal difference of the vertical component of magnetic field show peaks above the pipe. When comparing the width of response curves of both cases around the peak, horizontal difference of vertical component of magnetic field shows much narrower peak, 2 times narrower at a half of maximum amplitude, than that of horizontal component of magnetic field. Accordingly, we can pinpoint the horizontal location of pipe on the ground more accurately by measuring the horizontal difference of vertical component of magnetic fold. Moreover, it will have a merit in determining the depth of pipe, because the equation for depth estimation is defined just above the pipe. When there are two buried pipes separated by two meters with each other, the response of horizontal difference of vertical component of magnetic field has two separate peaks each of which is located above the pipe whereas horizontal magnetic field response has only one peak above the pipe just below the transmitter. Thus, when there exist more than a buried pipe, measuring the horizontal difference of vertical magnetic field can effectively detect not only the pipe under transmitter but also adjacent ones. The width of response curves also indicates higher resolving ability of horizontal difference of vertical component of magnetic field.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.3
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• pp.307-317
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• 2023

Due to increasing demand for aesthetics, zirconia crowns have become a popular choice for treating primary molars. However, there is limited literature available comparing the survival rates of zirconia crowns with those of other restorative materials. The objective of this study was to compare the 36-month survival rates of zirconia crowns and stainless steel crowns for proximal caries, as well as to analyze failure types associated with each crown type. Electronic medical records and radiographs of 1,061 primary molars from 498 patients treated with 2 types of prefabricated crowns at Chosun University Dental Hospital and 2 private dental clinics between 2017 and 2019 were collected and analyzed. The survival rate of zirconia crowns was found to be lower compared to that of stainless steel crowns. Regarding the groups without pulp treatment, the survival rate of stainless steel crowns was significantly higher than that of zirconia crowns. However, in the groups that received pulp therapy, no significant difference in the survival rates was observed between the two preformed crowns. Notably, abnormal root resorption or periapical lesions were identified as the primary cause of restorative failure in stainless steel crowns, whereas loss of restoration was the predominant cause in zirconia crowns. This study holds valuable implications for clinicians when selecting preformed crowns for primary molars.