• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.547-554
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• 2004

The surface characteristics of restoration such as surface roughness and droplet contact angle are important part for the process of bacterial adhesion. The purpose of this study is to compare plaque adhesion by measuring roughness, droplet contact angle, and amount of accumulated plaque on the surfaces of composite resins. Four kinds of composite resins, Z-100(Z1), Durafil(DF), Filtek supreme(FS), Clearfil AP X(CA) were used. Ten samples were divided into unpolished and polished group. Surface roughnesses and droplet contact angles were measured by profilometer and goniometer. Plaque weight gains are measured. The results were as follows: 1. The experimental group were rougher than the control group. Surface roughnesses were decreased in the following order; (Z1, DF, CA)>FS in the control group, and CA>Z1>(FS, DF) in the experimental group(P<0.05). 2 The control group showed larger contact angle than the experimental group. Contact angles were decreased in the following order; CA>(FS, DF, Z1) in the control group, and (CA, DF)>(FS, Z1) in the experimental group(P<0.05). 3. The experimental group showed more much plaque than the control group. The amounts of plaque accumulation in vitro were decreased in the following order; Z1>(DF, FS)>CA in the control group, and Z1>FS>(CA, DF) in the experimental group. The latter showed more much plaque than the former(P<0.05). 4. There were stronger correlation between plaque deposition and contact angle (P<0.05) than that of plaque deposition and surface roughness.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1369-1382
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• 2007

To find proper water quality management strategy for oxygen consumption organic matters in Jinhae bay, the physical process and net supply/decomposition in terms of COD was estimated by three-dimensional eco-hydrodynamic modeling. The estimation results of physical process in terms of COD showed that transportation of COD was dominant in loading area from land to sea, while accumulation of COD was dominant in $middle{\sim}bottom$ level. In case of surface level, the net supply rate of COD was $0{\sim}60\;mg/m^2/day$. The net decomposition rate of COD was $0{\sim}-0.05\;mg/m^2/day$($-5{\sim}-10$ m, in depth) to 2 level, and $-0.05{\sim}-0.20\;mg/m^2/day(10m{\sim})$ to bottom level. These results indicate that the biological decomposition and physical accumulation of COD are occurred for the most part of Jinhae Bay bottom. The variation of net supply or net decomposition rate of COD as reducing land based input loading is also remarkable. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters to improve the water quality of Jinhae Bay.

• Ocean and Polar Research
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• v.24 no.3
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• pp.227-236
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• 2002

For ten firn cores, from both the eastern and the western side of Lambert Glacier basin (LGB), snow accumulation rate and isotopic temperature were measured far the recent 50 years. Results show that snow accumulation for five cores over the eastern side of LGB (GC30, GD03, GD15, DT001, and DT085) at Wilks Land and Princess Elizabeth Land increases, whereas it decreases at the western side (Core E, DML05, W200, LGB 16, and MGA) at Dronning Maud Land, Mizuho Plateau and Kamp Land. For the past decades, the increasing rate was $0.34-2.36kg\;m^{-2}a^{-1}$ at the eastern side and the decreasing rate was $-0.01\;-\;-2.36kg\;m^{-2}\;a^{-1}$ at the western side. Temperatures at the eastern LGB were also increased with the rate of $0.02%o\;a^{-l}$. At the western LGB it was difficult to see clear trends, which were confirmed by Instrumental temperature records at coastal stations. Although statistic analysis and modeling results display that both surface temperature and accumulation rate has increased trends in Antarctic ice sheet during 1950-2000, the regional distributions were much more different for different geographic areas. We believe that ice-core records at Wilks Land and Princess Elizabeth Land reflect the real variations of SST and moisture change in the southern India Ocean. For the Kamp Land and Dronning Maud Land, however circulation pattern was different, by which the climate was more complicated. The International Trans-Antarctic Scientific Expedition (ITASE) aimed to reveal an overall spatial pattern of climate change over Antarctic ice sheet for the past 200 years. This study points the importance of continental to regional circulation to annual-decadal scale climate change in Antarctica.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.4
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• pp.549-565
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• 1998

Porcelain is considered to be one of the materials of choice for restoration where esthetics is of concern. But porcelain surface without final glazing treatment may induce undesirable results such as inflammatory response on adjacent soft tissues due to plaque accumulation and increased wear of opposing teeth. Therefore, rough porcelain surface must be smoothened by final glazing treatment or chairside polishing procedure. The purpose of this study was to compare the surface roughness among self-glazed, overglazed and polished porcelain with various polishing kit, and to detect which phase of polishing is optimal in clinic. Specimens were fabricated with Vita VMK porcelain. The surface treatment of each group was performed as follows. Group 1 : overglazing treatment Group 2 : self-glazing treatment Group 3 : polishing with the Truluster Polishing System for Porcelain(Brasseler, U.S.A.) Group 4 : polishing with the Exa Cerapol Adjustment kit (Edenta dental products, Switzerland) followed by finishing with diamond-filled polishing paste Group 5 : polishing with the Shofu Porcelain Adjustment kit (Shofu inc., Japan) followed by finishing with diamond-filled polishing paste. At each polishing steps, the measurement of Ra and Rq values were performed, and the surface was examined by scanning electron microscope. The results were as follows : 1. Overglazing treatment brought smoother surface than self-glazing treatment. 2. Polishing systems without porcelain polishing paste did not make better result than self-glazing treatment. 3. Polishing system with porcelain polishing paste made similar result to overglazing treatment. 4. Applying diamond-filled polishing paste after using polishing system which has no porcelain polishing paste produced surface as smooth as overglazing treatment does.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.347-352
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• 1999

This cDNAs were cloned with the aid of the polymerase chain reaction (PCR) by sequences based on cloned rat LH/CG and FSH receptor cDNAs. A cDNAs of LHR and FSHR were transfected into the 293 cells. Several clonal cell lines were obtained expressing different numbers of cell surface receptors. One cell lines for each LHR and FSHR were chosen, and a corresponding cell lines expressing the wild type LHR and FSHR were selected based on the number of cell surface receptor for the particular LHR and FSHR. The abilities of the LHR and FSHR to transduce the hCG and FSH signals were measured by quantitating cAMP accumulation in cells incubated with increasing concentrations of hCG and FSH. The cAMP accumulation effects for these receptors were increased by the increasing concentrations of hCG and FSH. Thus, most of the receptors expressed in cells transfected with LHR and FSHR could be detected by measuring hormone binding and cAMP response, and can utilize to study the structure function and signal transduction of the choriogonadotropins and glycoprotein hormones.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1114-1119
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• 2004

The biofilms on pipe walls in water distribution systems are of interest since they can lead to chlorine demand, coliform growth, pipe corrosion, and water taste and odor problems. As such, the study described in this paper is part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different source waters on the water quality in various distribution systems. The project was based on 18 independent pilot distribution systems (PDS), each being fed by a different water blend (7 finished waters blended in different proportions). The source waters compared were groundwater, surface water, and brackish water, which were treated in a variety of pilot distribution systems, including reverse osmosis (RO) (desalination), both membrane and chemical softening, and ozonation-biological activated carbon (BAC), resulting in a total of 7 different finished waters. The observations from this study consistently demonstrated that unlined ductile iron was more heavily colonized by a biomass than galvanized steel, lined ductile iron, and PVC (in that order) and that the fixed biomass accumulation was more influenced by the nature of the supporting material than by the water quality (including the secondary residual levels). However, although the bulk liquid water cultivable bacterial counts (i.e. heterotrophic plate counts or HPCs) did not increase with a greater biofilm accumulation, the results also suggested that high HPCs corresponded to a low disinfectant residual more than a high biofilm inventory. Furthermore, temperature was found to affect the biofilms, plus the AOC was important when the residual was between 0.6 and 2.0 mg $Cl_2/l$. An additional aspect of the current study was that the potential of the exoproteolytic activity (PEPA) technique was used along with a traditional so-called destructive technique in which the biofilm was scrapped off the coupon surface, resuspended, and cultivated on an R2A agar. Both techniques indicated similar trends and relative comparisons among the PDSs, yet the culturable biofilm values for the traditional method were several orders of magnitude lower than the PEPA values.

• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.346-350
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• 2015

In this study, we carried out an investigation of the etch characteristics of TiO₂ thin films and the selectivity of TiO₂ to SiO₂ in adaptive coupled C1₂/Ar plasma. The maximum etch rate of the TiO₂ thin film was 136±5 nm/min at a gas mixing ratio of C1₂/Ar (75%:25%). The X-ray photoelectron spectroscopy (XPS) analysis showed the efficient destruction of oxide bonds by the ion bombardment as well as the accumulation of low volatile reaction products on the etched surface.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.37-39
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• 2009

The physicochemical properties of the fatty acid monomolecular Arachidic Acid, Stearic Acid films surface structure has been studied by AFM. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is gas state, liquid state, solid state. Formation that prevent when gas phase state and liquid phase state measure but could know organic matter that molecules form equal and stable film when molecules were not distributed evenly, and accumulated in solid state only.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.66-75
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• 1997

This study was undertaken to investigate tribology characteristics of the alumina ceramics($Al_2O_3$) of the various purity for the variation of ambient condition such as air and vacuum. The wear test was carried out under different experimental condition using the wear test device, which was designed for this study, and in which the annular surface of wear testing specimens as well as mate specimen made of STB2 steel, were subjected to sliding speed, applied load and the sliding distance. The results obtained were as follows. As the ambient pressure decreases, the friction coefficient increases because the protective layer made of absorption due to decrease of the amount of ambient gas can not be formed. As the friction coefficient paticularly for 85% alumina lower than 95% and 99.7% in the alumina purity increases by an influence of heat accumulation caused by small elastic modulus and thermal conductivity. The friction surface of ceramics can be protected in the air by the influence of the oxides transfered from STB2. However, in the vacuum, the protective layer made of the absorption substance can not be formed due to the decrease of ambient gas.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.41-46
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• 2003

In recent days, it is usual case to extend the dwelling area to the balcony which is provided by service area. But the use of the extended area can be arisen discomfort with a view point of thermal environment by excessive heat accumulation in summer and excessive cold draft in winter. In this study, the skills were reviewed to improve the thermal environment of the extended area and evaluations were carried out. Additional heat supply by heat-convector installed at the lower end of the curtain wall can improve the thermal environment of the extended area and also arise surface temperature of the curtain wall surface. And aluminum plate installed under the floor could not improve the thermal environment but it was effective to shortening the initial heating time.