• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.827-832
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• 2005

In this study, thin electrolyte layer was prepared by 8YSZ ($8mol\%$ Yttria-Stabilized Zirconia) slurry dip and sol coating onto the porous anode support in order to reduce ohmic resistance. 8YSZ polymeric sol was prepared from inorganic salt of nitrate and XRF results of xerogel powder exhibited similar results $(99.2\pm1wt\%)$ compared with standard sample (TZ-8YS, Tosoh Co.). The dense and thin YSZ film with $1{\mu}m$ thickness was synthesized by coating of 0.7M YSZ sol followed by heat-treatment at $600^{\circ}C$ for 1 h. Thin film electrolyte sintered at $1400^{\circ}C$ showed no gas leakage at the differential pressure condition of 3 atm.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.98-103
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• 2007

To isolate probiotic lactic acid bacteria for animal, we have screened the microorganisms from chicken feces, by random selection and agar well diffusion assay. Among them, CPM-7 strain showing superior inhibitory activity against Escherichia coli was selected. By examining carbohydrates utilization, morphologic property and 16S rRNA gene sequence, CPM-7 strain was identified as Lactobacillus salivarius, then named L. salivarius CPM-7. L. salivarius CPM-7 produced thirteen enzymes in the test using API ZYM kit, and showed resistance to low pH and bile salts. It survived at pH 2 for 30 min. and pH 3 for 6 hr. And, it was able to grow in MRS medium containing 0.2% (w/v) bile salts. L. salivarius CPM-7 adhered to the jejunal epithelium cells of pig. Both the supernatant of L. salivarius CPM-7 and the its neutralized one showed high inhibitory activity against E. coli K88.

• Journal of Welding and Joining
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• v.35 no.3
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• pp.68-74
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• 2017

Characteristics of dissimilar metal welds between alloy steel ASTM A387 Gr. 91 and carbon steel ASTM A516 Gr.70 made with Flux cored arc welding(FCAW) have been evaluated in terms of microstructure, mechanical strength, chemical analysis by EDS as well as corrosion test. Three heat inputs of 15.0, 22.5, 30.0kJ/cm were employed to make joints of dissimilar metals with E71T-1C wire. Post-weld heat treatment was carried out at $750^{\circ}C$ for 2.5 h. Based on microstructural examination, Intragranular polygonal ferrite and grainboundary ferrite were formed only in first layer of weld metal. Another layers consisted of acicular ferrite and $Widmannst{\ddot{a}}tten$ ferrite. The amount of acicular ferrite was increased with decreasing heat input and layer. Heat affected zone of alloy steel showed the highest hardness due to the formation of tempered martensite and lower bainite. Lower and upper bainite were formed in heat affected zone of carbon steel. Tensile strengths of dissimilar metal welds decreased with increasing heat inputs. Dissimilar metal welds showed a good hot cracking resistance due to the low HCS index below 4. The salt spray test of dissimilar metals welds showed that the weight loss rate by corrosion below 170 hours was decreased with increasing heat inputs due to the increase of the amount of acicular ferrite.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.565-568
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• 2008

Domestic area of most be happened chloride deicer damage. Because daily mean temperature is below 0$^{\circ}C$ from the area of domestic most. Concrete durability influence Air Content. Presently, We used to AE(air-entraining agent) for increase freeze-thaw durability. So, on concrete Air Spacing ratio used $200{\mu}m{\sim}230{\mu}m$ in Canada and under $250{\mu}m$ in Japan institution. Use of Air content has been and will continue to be a major part of concrete durability and scaling. Chloride-containing chemicals such as calcium chloride or rock salt are main deicers for the road. The prepared optimum mix concrete in this study show that freeze-thaw and scaling resistance of Non-AE(air content 1.5%) and AE (air content 4.5%, 7.2%). Solution concentrations of deicing agent were good result, and the pore system and change of hydration products is not difference comparing before freeze-thaw test.

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.236-246
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• 2010

In preparative anti-corrosive coating experiments, polyaniline was obtained by reacting an oxidizing agent with the monomer aniline. Further, the primer coating was prepared using a variety of widely-used materials such as urethane resin. For the top coating, epoxy resin and acrylic urethane resin were used. Characteristics of the coatings were assessed according to KS and ASTM specifications, and the structure of the polyaniline was characterized using FT-IR and TGA. For analysis of anti-corrosive properties in salt-spray experiments, measurements of the oxidation state of iron and surface atomic analysis were conducted using XPS and SEM-EDX. Unlike general anti-corrosive coatings which exhibit anti-corrosive effects only as a primer coating, the anti-corrosive coatings using polyaniline as the anti-corrosive pigment showed a marked synergistic effect with the top coatings. In other words, the top coatings not only produce a fine view effect, but also increase, through interaction with the primer coatings, the resistance to diffusion of corrosive factors from the external environment. It was also found that, unlike the heavy metal oxide-forming layer of the passive barrier alone, the polyaniline anti-corrosive pigment oxidized iron at the interface with the iron substrate to form a passive barrier in the oxidic layer, and itself formed a potential barrier layer with anti-corrosive factors from the external environment. Although the passive layer was damaged, the damaged area did not become completely oxidized iron; on the contrary, it showed a tendency to reduction. This can be interpreted such that a passive layer is formed again on the damaged area, and that at the same time there is a tendency to self-healing.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.53-58
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• 2017

In this study, to overcome a complicated shoe adhesion process such as buffing, pre-treatment by primer in the rubber component of the shoe, we studied adhesion and mechanical properties with rubber compound added $MgCl_2$. We determined adhesion properties of $MgCl_2$ content. Especially, the rubber containing $MgCl_2$ exhibited good adhesion properties to water-based adhesion. Since $MgCl_2$ is a water-soluble salt, it was judged that this phenomenon occurred. The results are confirmed by contact angle and surface morphology measurement. In addition, in the case of rubber compound added $MgCl_2$, the crosslinking efficiency was increased and the NBS resistance was increased.

• Corrosion Science and Technology
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• v.6 no.5
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• pp.219-226
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• 2007

Pre-construction primer (PCP), or shopprimer, have been applied to steel plates to control temporary corrosion during ship fabrication. For surface preparation at ship block stage, in common shipyard practices, welding beads, burnt and rusted areas shall be blasted or power tool cleaned and the contamination such as zinc salt shall be removed with blasting or power tool. Whereas, the sound film of PCP needs not to be removed or roughened as the paint having good compatibility with PCP is used for the first coat. In many cases, however, full blasting or sweep blasting on the sound PCP treated block assemblies was requested. There still has been argument about the legitimacy of this practice, thus, it is critical to evaluate the quality of the coating system applied on the sound PCP retained condition, comparing with the one applied on the full blasted or sweep blasted condition. In this study, two different epoxy systems for water ballast tank were applied on the surfaces with sound PCP condition, full blasted condition, and sweep blasted condition. Coating performances such as durability, anti-corrosion, cathodic disbondment resistance were evaluated. The test results clearly indicated that the sound film of PCP needed not to be removed or roughened as the paint having good compatibility with PCP based on inorganic zinc silicate.

• Korean Journal of Microbiology
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• v.9 no.2
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• pp.55-60
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• 1971

Among 50 yeasts of red pepper paste isolated and identified in the previous report, 12 strains of yeast which possess osmophilic and non-film characteristics were examined their growth rates and alcohol fermentation ability in red pepper medium. 5 strains of yeast possessing powerful growth rates and excellent alcohol fermentation ability were selected as excellent yeasts in this experiment. And their cultural conditions, salt resistance and red pepper concentration upon the growth were examined in this report. The results obtained were as follows ; 1) Among 12 strains of yeast, Saccharomyces cerevisiae group II(strain $D_1$), Saccharomyces oviformis($D_2$), Saccharomyces steineri($M_3$), Saccharomyces rouxii($D_9$) and Saccharomyces mellis($G_8$) were selected as excellent yeasts. 2) Among 5 strains of yeast selected, the strain $D_1$ and $D_2$showed the best alcohol fermentation ability and the best fermentative flavour. 3) The optimum temperature for growth of the strain $D_1$ and $D_2$ was $25^{\circ}C$$M_3$, $D_9$ and $G_8$ $30^{\circ}C$$D_1$ and $D_2$ was $62^{\circ}C$$M_3$,$D_9$ and $G_8$ ws 60.deg.C with treatment for 10 minutes. 4) The optimum pH for growth of all strains was around 5.0. 5) The strain $D_1$ and $M_3$were grown exceedingly well on the emdia containing 3 percent of NaCl and $D_2$,$D_9$ and $G_8$ on the media containing 6 percent of NaCl. 6) In the case of 5 percent of red pepper liquor added 5 percent of glucose was more nutritional than in the case of 5 percent glucose only. However, the growth rates of yeasts were restrained by the increase of red pepper concentration.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.334-344
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• 2014

The objective of this study was to evaluate the microbiological and physicochemical characteristics, and the antagonistic activity against Helicobacter pylori ATCC 43504, of yogurt fermented with the lactic acid bacteria from Baikkimchi kept under cold storage. The viable cell counts, titratable acidity, viscosity, and total solid content of the yogurt were different according to the bacterial strains used for fermentation. There was no significant change (P>0.05) in the various properties of refrigerated yogurt. Among the tested strains, the strongest resistance against artificial gastric juice and bile salt was found for Lactobacillus brevis BK11 and Lactobacillus paracasei BK57. Due to high lactic acid levels obtained from these two lactic acid bacteria, yogurt may show good anti-Helicobacter effects according to the time-kill assay. In particular, yogurt fermented with L. brevis BK11 significantly reduced the number of H. pylori adhering to gastric epithelial AGS cells and the urease activity of this pathogen (P<0.05).

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.397-405
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• 2001

In clod weather regions, a strong seasonal wind brings sea salts to the land. In addition to it, recently, the spreading amount of deicing salts has increased numerously for purpose of removing snow and ice. Thus the salts environment around concrete structures becomes so severe that various damages of concrete due to applied salts will be brought up. Much of countries such as America, Europe etc. is carried out study for effects of deicing salts on concrete. However, there are not test methods for deterioration of concrete subjected to both freezing-thawing and chloride in Korea. In this study, we carried out test for the compound deterioration subjected to both freezing-thawing and chloride attack, to investigate the effects of sodium chloride on the deterioration of concrete. The test was performed to investigate the effects of cement type, strength and air content on the scaling deterioration of concrete. As a result, the scaling deterioration was accelerated in the presence of salts. And the resistance to scaling was strongly influenced by the type of cement, the strength and air content of concrete.