• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.97-102
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• 2008

Purpose: Periodontal intrabony defects have great deal of importance since they contribute to the development of periodontal disease. Current treatment regimens for intrabony defects involve grafting of numerous bony materials, GTR using biocompatible barriers, and biomodification of root surface that will encourage the attachment of connective tissue. Xenograft using deproteinized bovine bone particles seems to be very convenient to adjust because it doesn't require any donor sites or imply the danger of cross infections. These particles are similar to human cancellous bone in structure and turned out to be effective in bone regeneration in vivo. We here represent the effectiveness of grafting deproteinized bovine bone particles in intrabony defect and furcation involvements that have various numbers of bony walls. Materials and methods: Open flap debridement was done to remove all root accretions and granulation tissue from the defects within persisting intrabony lesions demonstrating attachment loss of over 6mm even 3 months after nonsurgical periodontal therapy have been completed. Deproteinized bovine bone particles($BBP^{(R)}$, Oscotec, Seoul) was grafted in intrabony defects to encourage bone regeneration. Patients were instructed of mouthrinses with chlorohexidine-digluconate twice a day and to take antibiotics 2-3 times a day for 2 weeks. They were check-up regularly for oral hygiene performance and further development of disease. Probing depth, level of attachment and mobility were measured at baseline and 6 months after the surgery. The radiographic evidence of bone regenerations were also monitored at least for 6 months. Conclusion: In most cases, radio-opacities increased after 6 months. 2- and 3-wall defects showed greater improvements in pocket depth reduction when compared to 1-wall defects. Class I & II furcation involvements in mandibular molars demonstrated the similar results with acceptable pocket depth both horizontally and vertically comparable to other intrabony defects. Exact amount of bone gain could not be measured as the re-entry procedure has not been available. With in the limited data based on our clinical parameter to measure pocket depth reduction following $BBP^{(R)}$ grafts, it was comparable to the results observed following other regeneration techniques such as GTR.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.3
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• pp.212-220
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• 2015

Purpose: Candida albicans can cause mucosal disease in many vulnerable patients. Also they are associated with denture-related stomatitis. Electrolyzed water is generated by electric current passed via water using various metal electrodes and has antimicrobial activity. The aim of this study was to investigate antifungal activity of electrolyzed water on C. albicans biofilm. Materials and Methods: C. albicans was cultured by sabouraud dextrose broth and F-12 nutrient medium in aerobic and 5% $CO_2$ condition to form blastoconidia (yeast) and hyphae type, respectively. For formation of C. albicans biofilm, C. albicans was cultivated on rough surface 6-well plate by using F-12 nutrient medium in $CO_2$ incubator for 48 hr. After electrolyzing tap water using various metal electrodes, the blastoconidia and hyphal type of C. albicans were treated with electrolyzed water. C. albicans formed blastoconidia and hyphae type when they were cultured by sabouraud dextrose broth and F-12 nutrient medium, respectively. Results: The electrolyzed water using palladium electrode (EWP) exhibited antifungal effect on blastoconidia of C. albicans. Also, the EWP significantly has antifungal activity against C. albicans biofilm and hyphae. In the electrolyzed water using various metal electrodes, only the EWP have antifungal activity. Conclusion: The EWP may use a gargle solution and a soaking solution for prevention of oral candidiasis and denture-related stomatitis due to antifungal activity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.62-62
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• 2008

As micro-system move toward higher speed and miniaturization, requirements for embedding the passive components into printed circuit boards (PCBs) grow consistently. They should be fabricated in smaller size with maintaining and even improving the overall performance. Miniaturization potential steps from the replacement of surface-mount components and the subsequent reduction of the required wiring-board real estate. Among the embedded passive components, capacitors are most widely studied because they are the major components in terms of size and number. Embedding of passive components such as capacitors into polymer-based PCB is becoming an important strategy for electronics miniaturization, device reliability, and manufacturing cost reduction Now days, the dielectric films deposited directly on the polymer substrate are also studied widely. The processing temperature below $200^{\circ}C$ is required for polymer substrates. For a low temperature deposition, bismuth-based pyrochlore materials are known as promising candidate for capacitor $B_2Mg_{2/3}Nb_{4/3}O_7$ ($B_2MN$) multi layers were deposited on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system at room temperature. The physical and structural properties of them are investigated by SEM, AFM, TEM, XPS. The dielectric properties of MIM structured capacitors were evaluated by impedance analyzer (Agilent HP4194A). The leakage current characteristics of MIM structured capacitor were measured by semiconductor parameter analysis (Agilent HP4145B). 200 nm-thick $B_2MN$ muti layer were deposited at room temperature had capacitance density about $1{\mu}F/cm^2$ at 100kHz, dissipation factor of < 1% and dielectric constant of > 100 at 100kHz.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.736-746
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• 2011

This study aims tried to present develop a management plan for about old and big trees and legally protected trees by investigating through the present the current status and the distribution of the legally protected trees and old and big tree that range in Gwangju, South Korea. The number of legally protected plants that distributed in Gwangju City is 68 individual trees from 9 species. The largest number was found in Gwangsan-gu (18 trees). The total number of the old and big trees that are distributed in Gwangju City was confirmed as 155 individual trees from 10 species. It must to be corrected to a correct plant species name that species name is written in review articles incorrectly. The average vitality rate of the legally protected plants was 1.2 and the status of ground was 1.7 on average. And the vitality rate of the old and big trees was 1.3 and the status of ground was 2.0 on average. Vitality are not significantly different between the legally protected trees and old and big trees. Ground status of old and big trees worse than legally protected trees. Gingko biloba (found in Gwangsan-gu Songdaedong Daechon village) was only legally protected plant that requires urgent management due to low vitality rate (between 3.2 and 4.0). Among old and big trees Salix glandulosa which is found in Gwangsan-gu Sansu-dong Gamdong village was only one that requires urgent care. The most important status for the old and big tree is securing minimal space for growth. Therefore, we conclude that the most urgent measure in the management and projection of old and big trees and legally protected plants is removal of asphalt or cement above the surface of root system.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.1
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• pp.12-31
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• 1999

Topex/Poseidon satellite altimetric data are used to estimate characteristics on the oceanic and atmospheric correction factors, and the mean sea level and its variations in the Yellow Sea, the East China Sea and the East Sea from September 1992 through August 1994(70cycles). For the atmospheric correction factors, the variations of dry troposphere, humid troposphere, ionosphere and inverted barometer were very small as a few centimeters, but the variations of electromagnetic bias were higher than other factors. For the oceanic correction factors, the variations of ocean tide(35cm in track 127 and 60cm in track 214) showed high ranges compared to elastic tide(5cm in track 127 and 1cm in track 214) and loading tide(1.8cm in track 127 and 1cm in track 214). It should be understood that the variations of ocean free surface is mainly under the influence of, firstly, ocean tide and, secondly, electromagnetic bias. Mean sea level in the Yellow Sea are higher than in the rest of Seas. Then its range generally comprised between -60cm and 210cm with mean value of about 100cm. Also its variations showed high values in the Yellow Sea and East China Sea, especially 5.689cm in Youngampo. This result is mainly due to the effects of local topography and tidal current.

• Corrosion Science and Technology
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• v.13 no.1
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• pp.28-35
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• 2014

Recently, the fuel oil of diesel engines of marine ships has been increasingly changed to heavy oil of low quality as the oil price is getting higher and higher. Therefore, the spiral gear attached at the motor of the oil purifier which plays an important role to purify the heavy oil is also easy to expose at severe environmental condition due to the purification of the heavy oil in higher temperature. Thus, the material of the spiral gear requires a better mechanical strength, wear and corrosion resistance. In this study, the heat treatment(tempering) with various holding time at temperature of $500^{\circ}C$ was carried out to the alloy of Cu-7Al-2.5Si as centrifugal casting, and the properties of both hardness and corrosion resistance with and without heat treatment were investigated with observation of the microstructure and with electrochemical methods, such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram, and a.c. impedance. in natural seawater solution. The ${\alpha}$, ${\beta}^{\prime}$ and ${\gamma}_2$ phases were observed in the material in spite of no heat treatment due to quenching effect of a spin mold. However, their phases, that is, ${\beta}^{\prime}$ and ${\gamma}_2$ phases decreased gradually with increasing the holding time at a constant temperature of $500^{\circ}C$. The hardness more or less decreased with heat treatment, however its corrosion resistance was improved with the heat treatment. Furthermore, the longer holding time, the better corrosion resistance. In addition, when the holding time was 48hrs, its corrosion current density showed the lowest value. The pattern of corroded surface was nearly similar to that of the pitting corrosion, and this morphology was greatly observed in the case of no heat treatment. It is considered that ${\gamma}_2$ phase at the grain boundary was corroded preferentially as an anode. However, the pattern of general corrosion exhibited increasingly due to decreasing the ${\gamma}_2$ phase with heat treatment. Consequently, it is suggested that the corrosion resistance of Cu-7Al-2.5Si alloy can be improved with the heat treatment as a holding time for 48 hrs at $500^{\circ}C$.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.121-126
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• 2015

In general, the pearlescent pigment is a pigment which was used for optical characteristics like pearl, rainbow and metallic luster. Titanium dioxide coated mica plate developed by DuPont in 1965 is currently being used as a main part of pearlescent pigment for cosmetics. Although the smooth and clear surface substrate laminated with 2 ~ 3 ingredients is thicker than a previous monolayer coated substrate, it has been applied for cosmetics as the optical interference powder to realize stronger shine and brighter interference color than monolayer one. In this study, we developed a new optical interference powder with thinner and higher chroma than a current pearlescent pigment for the strong luster and bright interference color. It was prepared from the manufacturing process, in which the coated titanium dioxide precursor was changed and crystallized by coating and heat treatment process with a half of dividing the coated amount of titanium dioxide. We confirmed the dense coating of titanium dioxide grain with Scanning Electron Microscope and measured superior crystallization degree compared with a monolayer coated pearlescent pigment by X-ray Diffraction. It is concluded that our new pearlescent pigment had higher reflectivity of light and stronger interference color than previous products.

• Geophysics and Geophysical Exploration
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• v.18 no.4
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• pp.223-231
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• 2015

Self-potential (SP) is sensitive to groundwater flow and there are many causes to generate SP. Among many mechanisms of SP, pore-fluid flow in porous media can generate potential without any external current source, which is referred to as electrokinetic potential or streaming potential. When calculating SP responses on the surface due to geothermal fluid within an engineered geothermal system (EGS) reservoir, SP anomaly is usually considered to be generated by fluid injection or production within the reservoir. However, SP anomaly can also result from geothermal water fluid within EGS reservoirs experiencing temperature changes between injection and production wells. For more precise simulation of SP responses, we developed an algorithm being able to take account of SP anomalies produced by not only water injection and production but also the fluid of geothermal water, based on three-dimensional finite-element-method employing tetrahedron elements; the developed algorithm can simulate electrical potential responses by both point source and volume source. After verifying the developed algorithm, we assumed a simple geothermal reservoir model and analyzed SP responses caused by geothermal water injection and production. We are going to further analyze SP responses for geothermal water in the presence of water production and injection, considering temperature distribution and geothermal water flow in the following research.

• Fire Science and Engineering
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• v.28 no.5
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• pp.8-13
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• 2014

The purpose of this study is to analyze the damage pattern when overcurrent is applied to a thermal magnetic type molded case circuit breaker (MCCB) using a Primary Current Injection Test System (PCITS). When an overcurrent of 150 A was applied to the PCITS for 5 seconds with the trip bar of an MCCB being damaged, it was found that the surface of the temperature control device (bimetallic strip) positioned at the right was significantly carbonized. When an overcurrent of 300 A was applied to the PCITS for 5 s under the same conditions, the entire temperature control device was deteriorated, becoming flattened and in close contact with the MCCB. When an overcurrent of 450 A was applied to the PCITS for 5 s, the coil of the temperature control device was melted and disconnected. In addition, it was observed that the contacts, the enclosure and upper cover were deformed and there was a trace of carbonization on them. When approximately 3 s had elapsed after an overcurrent of 600 A was applied, white smoke occurred inside the MCCB and a flame was radiated out, after which the overcurrent supply stopped with "phutt" (whomp) sound. It was observed that when the same type of MCCB is damaged by a general flame, the surfaces of its handle, terminal, arc divider (extinguisher) and temperature control device were carbonized uniformly. In addition, it was found that the trip bar of the operating mechanism was melted down and the metal operation pin was moved while being tripped.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.627-636
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• 2002

While typhoons were passing by the coastal and offshore waters around the Korean peninsula, the variations of the sea surface temperature (SST) were studied. To study on the variation, the data related to the 22 typhoons among 346 typhoons which occurred in the western Pacific during 1990∼1999, daily measured field SSTs at coastal and offshore, and imageries from advanced very high resolution radiometer on NOAA satellite during 1990∼1999 were used. The average variations of the SSTs were -0.9℃ at coastal waters and -2℃ at offshore around the Korean peninsula while the typhoons were passing by. In very near coastal waters from the land, the SST was not changed because the bottom depth of the coastal waters was shallower than the depth of thermalcline, while the typhoon was passing. The temporal and spatial variation of SSTs at coastal waters in summer were depended on the various types of the typhoons＇paths which were passing through the Korean peninsula. When a typhoon passed by the western parts including the Yellow Sea of the Korean peninsula upwelling cold water occurred along the eastern coastal waters of the peninsula. The reason was estimated with the typhoon that was as very strong wind which blew from south toward north direction along the eastern shore of the peninsula, led to the Ekman transport from near the eastern coastal area toward the offshore. While cold water was occurring in the eastern coast, a typhoon passed over the coastal area, the cold water disappeared. The reason was estimated that the cold water was mixed up with the surrounding warm water by the effect of the typhoon. While a cold water was occurring in the eastern coast, a typhoon passed by the offshore of the eastern coast, there were the increasing of the SST as well as the disappearing of the cold water. While a typhoon was passing by the offshore of the eastern coast, the cold water which resulted from the strong tidal current in the western coast of the peninsula was horizontally spread from the onshore to the offshore. We think that the typhoon played the role of the very strong wind which was blowing from north toward south. Therefore, the Ekman transport occurred from the onshore toward the offshore of the western coast in the Korean peninsula.