• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.1
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• pp.27-34
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• 2015

Many applications of nanoparticles have been developed since 1970s. Surface plasmon resonance (SPR) effect can be generated at the surface of nanoparticles by illumination. SPR is the resonant oscillation of conduction electrons at the surface material stimulated by incident light. The collisions between excited electrons and metal atoms can cause the production of thermal energy (photothermal effect). Here, we presented the development of thermo-cosmetics using photothermal effect of gold nanoparticles. Gold nanoparticles (GNPs) were chosen for it's low toxicity. We also and investigated the cell biocompatibility and heating effectiveness for photothermal effect of GNPs. Synthesized GNPs were verified by UV-vis spectrophotometer, where GNP has a characteristic absorbance spectrum. Concentration of GNP was measured by atomic absorption analyzer. The cytotoxicity was confirmed by MTT assay and double staining assay. Photothermal effect of GNP was demonstrated by the thermal increasing properties depending on GNP concentration, which was taken by an IR-thermal camera with a xenon lamp as the light source. If the thermal effect of GNP is applied for thermo-cosmetics, it can supply heat to skin by converting solar energy into thermal energy. Thus, cosmetics containing GNPs can provide benefits to people in the cold region or winter season for maintaining skin temperature, which lead to a positive effect on skin health.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.280-293
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• 2002

In this study, we analyzed the long-term distribution patterns of $CH_4$ determined from the Moo-Ahn (MAN) observatory in relation with those derived from the world major background monitoring sites. Comparison of the data were made using those data sets collected for the period between Aug. 1995 to Dec. 1991. The mean $CH_4$ concentration of MAN observatory was measured to be 1898${\pm}$85.3 ppb, recording the highest concentration of all the monitoring sites. When the concentration of $CH_4$ for different stations was compared over latitudinal scale, its concentration appeared to increase systematically as a function of latitude with an exception of MAN (and the other Korean monitoring site at Tae Ahn). Moreover, such phenomenon was more distinctive in Northern than Southern Hemisphere. According to the analysis of the monthly distribution patterns of $CH_4$ at MAN observatory, its concentration level began to increase from the months of February/March and peaked during August. In addition, when the level of oscillation in monthly concentrations (between the maximum and minimum values) was checked, differences were significant between MAN and other monitoring stations. If the rate of concentration change was checked using the data sets collected for this limited time period in terms of linear regression analysis, results for MAN showed the highest annual increasing rate of 16.5 ppb. It is hence suggested that the largest variability in the $CH_4$ distribution patterns at MAN observatory may be reflected by the high irregularity in its source/sink processes.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.215-223
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• 1973

A potent citric acid producing strain was selected by an extensive screening test of the yeasts isolated from the various sources. These experiments were conducted to identify the selected strain and investigate the cultural conditions for citric acid production. The results obtained were as fellows: 1. The selected strain of yeast was identified to Hansenula anomala var. anomala by a taxnoomic study of Lodder. 2. The optimum conditions for citric acid production in the basal medium containing 10% glucose were: temperature $30^{\circ}C$, the concentration of $CaCO_3$ 3% and the velocity of oscillation 110 oscills/min. 3. As a nitrogen source ol the basal medium $NH_4Cl(0.1%)$ was the most effective for citric acid production. Organic nitrogen sources such as peptone were adequate for growth of the strain but not for citric acid production. 4. The most effective concentration of glucose was 10% in yield ratio of citric acid from sugar. 5. The addition of defatted rape seed, defatted perilla or defatted rice bran to the medium was effective for citric acid production. When 5% extract solution of defatted rape seed was added, the citric acid production was increased as much as 40% as compared with the case of adding yeast extract(0.2%). 6. The most effective concentration of $KH_2PO_4$ and $MgSO_4{\cdot}7H_2O$ in the medium(for citric acid Production) was 0.05% and 0.025% respectively. 7. Under the optimum cultural conditions, the growth of the strain was continued up to 5 days and the increase of citric acid production was continued up to 6 days, showing the yield ratio of 46% to glucose.

• Journal of the Korean earth science society
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• v.22 no.4
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• pp.327-338
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• 2001

In this study, the short-term variability of methane concentrations were investigated over 24-hr scale. The data obtained form the Moo-Ahn (MAN) station located in the western coastal area of Korea were analyzed from various respects to describe its distribution characteristics over short term scale. The MAN data were compared with those obtained from the two major background observatory sites: Point Barrow (Alaska) and Mauna Loa (Hawaii). The mean concentration of methane for the whole study period, when computed using the daily mean values, was found to be 1898${\pm}$85.3ppb (N=812). The mean values for the two comparable sites were observed to be 1832${\pm}$29.6ppb (N=823) for Point Barrow and 1745${\pm}$14.8ppb (N=818) for Mauna Loa. According to the analysis of frequency distribution. the mode value for the MAN area is found to be 1900ppb, but the mean concentration for Point Barrow and Mauna Loa are shown to have relatively low values of 1850 and 1750ppb, respectively. When examined over diurnal scale, the CH$_4$data for the MAN area exhibit a rather consistent trend; CH$_4$level is low during the daytime (after 6:00 A.M) and rises during the nighttime. The findings of the generally enhanced methane concentration in the MAN station may be explained form various respects. One of the most important reasons is that the MAN area is under the influence of various source processes relative to all the other stations under consideration. The short-term distribution patterns for the MAN station are hence characterized not only by the high methane concentration but also by the high oscillation in its CH$_4$concentration level.