• Journal of Conservation Science
• /
• v.1 no.1 s.1
• /
• pp.60-79
• /
• 1992

In relation to the scientific conservation treatment of ancient gilt bronze, the gold film coated on the bronze excavated from Hwangnam Great Tomb of Old Silla Kingdom(A. D. 5C) was studied in the view of coating technology and metallurgy of bronze. The uniform and dense gold film containing $2.44\sim12.40%$ of Hg with the thickness of $5.99\sim12.97{\mu}m$ was found to be coated on the bronze objects by amalgam coating method. On silver objects, the film with the thickness of $19.96{\mu}m$ was coated also continously and uniformly with gold by the same method. The bronze objects was fabricated by forging technique and contained almost $4.7\sim11.5%$ of Pb. Its microstructure was $\alpha-phase$ solid solution including Pb segregation in the matrix. The amount of $0.4\sim2.0%$ Zn was added in the bronze for the purpose of easy fabricating of Cu alloy. Based on the data studied, the gold film on bronze sample was reproduced by amalgam coating method and compared with the ancient gold film.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.849-852
• /
• 2008

In the wheel tracking test to evaluate abrasion resistance for concrete surface coating materials applied parking lot, weight of the wheel, test temperature, scattered sand amount, wheel speed, etc. various test condition is used for reliable evaluating the abrasion resistance performance of surface coating materials and the results depends on the test condition. In this paper, we carried experimental study as following on abrasion resistance with 2kinds of different environmental conditions. - Commons : real car tire with 300kg of load, 5km/h of speed, 80,000 cycle. - Control A : no other deterioration condition - Control B : scattering 1.0g of sand per every 30rounds from 1m height.

• Korean Journal of Materials Research
• /
• v.25 no.10
• /
• pp.503-508
• /
• 2015

In this work, ceramic coatings were prepared on Al7075 aluminum alloy using microarc oxidation (MAO) process in a silicate-fluoride based electrolyte solution. The effect of $OH^-$ concentration, by adding NaOH to the solution on the microstructural and mechanical properties of the coating was investigated. Surface morphology and cross sectional view of the coating was analyzed using SEM while XRD was used to examine the phase compositions of the coatings. From XRD ${\alpha}-Al_2O_3$ phase was found to be increased by adding NaOH to the electrolyte. Thereby, the hardness and the wear properties of the MAO coatings were found to be superior to those of the coatings prepared without NaOH addition or with amount maximum than 2 g/l NaOH. Moreover, the morphology of the coatings was transformed form nodule-based cluster to crater based structure with the addition of NaOH to the MAO electrolyte solution.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.5
• /
• pp.1-8
• /
• 2014

In this study, the influence of the physical properties of ink such as ink dispersity and emulsified amount on the printability of a coated paper was investigated with seven kinds of cyan inks. In addition, two kinds of coating formulations were tested to evaluate the effect of coating structure on the coated paper printability. It was found that the cyan ink with $2{\mu}m$ pigment size had the best dispersibility and hence the ink showed a best ink density on the two kinds of coated papers. When the emulsified ink A with IPA 20 wt% had a lower viscosity than emulsified ink B with IPA 10 wt%, the emulsified ink A showed relatively high value of the ink transfer rate in comparison with emulsified ink B. Despite the high value of ink transfer rate, the coated paper did not show a good printability because those inks with low viscosity due to a strong emulsification were easy to make print mottle on the coated paper.

• Progress in Superconductivity and Cryogenics
• /
• v.4 no.1
• /
• pp.13-16
• /
• 2002

$SrZrO_3 $resistive oxide barriers on Ag sheathed Bi2223 tapes were prepared by the sol-gel and dip coating method to reduce AC coupling loss. The performance of the dip-coated $SrZrO_3 $ thin films was evaluated in terms of bond strength by varying the Sr/Zr mol ratio and the amount of organic vehicle (ethyl cellulose and a-terpineol) additives. The bond strength of the coatings increased as the Sr/Zr ratio decreased and the amount of organic vehicle rose, respectively. It was found that the effect of organic vehicle addition was more pronounced, suggesting that the adherence of the $SrZrO_3 $ films on Bi2223 tapes was governed primarily by the amount of organic vehicle additive.

• Journal of the Korean institute of surface engineering
• /
• v.31 no.1
• /
• pp.24-33
• /
• 1998

Effects of pH and supporting salts on the characteristics of electrogalvanzied coating in sulfate bath are investigated. The fine grain size is obtained and the whiteness with the amount of supporting salts or pH increased at more than current density of 100A/$dm^2$<\TEX>, With supporting salts increased, the electro-conductivity of the bulk solution increases and the cell voltage decreases, while the width of the cathode burned edge gets wider because it seems that the increased overpotential the vicinity of cathode causes the decreases, of limiting current density. When the amount of supporting salts or pH of sulfate bath decreases, the zinc crystals have preferred orientation (001) planes. However when the amount of supporting salts or pH increase, the crystal texture has less (001) planes and gets to have random crystal planes.

• The Journal of Korean Medicine
• /
• v.31 no.1
• /
• pp.23-29
• /
• 2010

Objective: The aim of this prospective, case-controlled study was to assess the difference of the amount of tongue coating between halitosis and non-halitosis patients using a digital tongue diagnosis system (DTDS). Methods: Sixty-five patients complaining of oral malodor were recruited for the study. The level of volatile sulfur compounds (VSC) in the oral cavity of the patients was measured by a portable gas chromatography. All patients were then divided into two groups, the halitosis group ($H_2S{\geq}1.5ng$/10ml, or $CH_3SH{\geq}0.5ng$/10ml) and the non-halitosis group ($H_2S$<1.5ng/10ml and $CH_3SH$<0.5ng/10ml), according to the VSC level criteria published by Tonzetich. Tongue images of the two groups were acquired and analyzed by DTDS, followed by the analysis of the tongue coating scores. Results: The tongue coating scores of the halitosis group were significantly higher than of the non-halitosis group (P=0.033). Furthermore, the difference of the posterior tongue coating between the two groups was more significant (P=0.000). Conclusions: Halitosis patients were shown to have a thicker tongue coating than those in the non-halitosis group. Moreover, the posterior dorsum of the tongue should be observed more cautiously when dealing with halitosis patients. Also, the progress and state of the patient's symptom of halitosis as diagnosed objectively by the portable gas chromatography could also possibly be analyzed instead by the DTDS tongue coating score.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.4
• /
• pp.229-236
• /
• 2014

In this study, the method to improve the electrochemical performance of $LiFePO_4$ by carbon coating and morphology control into porous structure was studied. The synthesis of $LiFePO_4$ was done by coprecipitation method by two step procedure. In the first step $FePO_4$ precursor was synthesized by coprecipitation method, followed by impregnation of lithium into the precursor at $750^{\circ}C$. The carbon coating was done by both physical and chemical coating processes. Using the physical coating process, the amount of coating layer was 6% and the capacity achieved was 125 mAh/g. In case of chemical coating process, the active material delivered 130~140 mAh/g, which is about 40% improvement of delivered capacity compared to uncoated $LiFePO_4$. For the morphology control into porous structure, we added nano particles of $Al_2O_3$ or $SiO_2$ into the active materials and formed the nanocomposite of ($Al_2O_3$ or $SiO_2$)/$LiFePO_4$. Between them, $SiO_2/LiFePO_4$ porous nanocomposite showed larger capacity of 132 mAh/g.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.24 no.1
• /
• pp.148-172
• /
• 1997

Sixty human premolar teeth were used for this in vitro study. After each tooth was sectioned mesiodistally, one half was used for the experimental group and the other half for the control. Three groups were made for each fluoride applying method and twenthy teeth were assigned to each group. Ten teeth were used for evaluating total fluoride amount and the other ten were used for firmly-bound fluoride. Fluorshield was used for fluoride-releasing sealant and 1.23% APF, 0.05% NaF were used for topical application fluorides. Each tooth was cleaned with a tooth brush using nonfluoride containing pumice before the experiment. In the sealant group, fluoroshield was applied to the enamel surface without etching procedure and stored in $37^{\circ}C$ saline for 30 days. After 30 days, sealant was removed with explorer without scratching the enamel surface and washed with distilled water and dried. In the APF group, each tooth was immersed in 1.23% APF for 30 min then washed and dried in the same manner. In the NaF group, each tooth was immersed in 0.05% NaF for 24 hours then washed and dried as described above. After each fluoride regimen was applied, ten teeth were randomly selected from each group and immersed in 1M KOH solution for 24 hours to remove loosely-bound fluoride possibly deposited by the three different fluorides applied. In each group, total fluoride amount deposited and the amount of enamel removed by acid biopsy were calculated. After loosely-bound fluoride was removed, firmly-bound fluoride deposited and the amount of enamel removed by acid biopsy were also calculated. Total fluoride amount deposition was significantly increased in the APF and NaF groups, but not in the sealant group. Amount of enamel removed by acid-biopsy was also significantly diminished in the APF and NaF groups, but not in the sealant groups. After loosely-bound fluoride was removed from each groups, no statistical difference was found in the amount of firmly-bound fluoride in any groups. Also no effect of firmly-bound fluoride on enamel dissolution was shown in any groups after loosely-bound fluoride was removed from each group. In conclusion, topical application method of APF or NaF is more effective than fluoride-releasing sealant application to make $CaF_2$ coating on enamel surface and $CaF_2$ coating is the main source for anticariogenic effect of fluoride. However, longterm anticariogenic effect of fluoride-releasing sealant should be further evaluated.

• Journal of Environmental Health Sciences
• /
• v.26 no.3
• /
• pp.103-110
• /
• 2000

This study was conducted from January to December in Kwang-ju city, 1999. Calculated methods were studied by emission factors in each industrial species. The results was that total emission rate of VOC was calculated at a mount of 12305 ton/year as coating(49.4) > vehicles(27.4) > gasoline vapors(6.1) > petroleum refineries(5.6) > graphic arts(4.4) > road covering(4.1) > dry cleang(3.0%) respectively. In vehicles emission rate, passenger car and taxi were about 2,700 ton/yr(60%) of total vehicle emission(3,300 ton/yr). The amount of building emission rate was about 1,900 ton/yr(30%) of total coating emission 6,083 ton/yr.