• Journal of Astronomy and Space Sciences
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• v.34 no.2
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• pp.99-103
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• 2017

The sun is not equally bright over the whole sphere, but rather is darkened toward the limb. This effect is well-known as limb darkening. The limb darkening coefficient is defined by the ratio of the center intensity to limb intensity. In this study, we calculate the limb darkening coefficient using the photospheric intensity estimated from solar images taken by solar and helispheric observatory (SOHO) and solar dynamics observatory (SDO). The photospheric intensity data cover almost two solar cycles from May 1996 to December 2016. The limb darkening coefficient for a size of 0.9 diameter is about 0.69 and this value is consistent with solar limb darkening. The limb darkening coefficient estimated from SOHO shows a temporal increase at solar maximum and a gradual increase since the solar minimum of 2008. The limb darkening coefficient estimated from SDO shows a constant value of about 0.65 and a decreasing trend since 2014. The increase in the coefficient reflects the effect of weakened solar activity. However, the decrease since 2014 is caused by the aging effect.

• Journal of the Korean Home Economics Association
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• v.18 no.1
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• pp.25-33
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• 1980

Effect of various batter ingredients o acid value, peroxide value, darkening of oil, and changes in volume after frying at 180- $190^{\circ}C$ for 3 times were determined. Organoleptic evaluation was also performed on the fried products. Fried product wit egg yolk raised the acid value, absorbed volume and darkening of frying oil than the control but the peroxide value was the lowest. on the contrary, fried product without egg lowered the acid value, absorbed volume and darkening of frying oil than the control but the peroxide value was high, and the sensory evaluation scores were generally higher in fried product without egg than in the product with egg yolk. In genera, fired products with potato, or potato plus ascorbic acid or carrot lowered the acid value, peroxide value, absorbed volume, and the darkening of frying oil. fried potato 0products were also favorable to the taste panel.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.251-252
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• 2008

We fabricated silica glass optical fiber containing PbSe quantum-dots (QD) of average size 3.2 nm. The response time of the PbSe-QD doped optical fiber was measured to be around 200 ps. However, after exposure to 1064 nm laser emission for 15 minutes, the response time dramatically reduced to around 2.5 ps, which may be due to photo-darkening effect.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.325-332
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• 1969

An attempt has been made to investigate the nature of the characteristic darkening reaction occurring in the rice bran oil during the storage. Several pigments were separated by using column and thin layer chromatography of the pigments was made in the light of the knowledge of absorption spectral behavior. The presence of trace amount of iron and phytosteryl esters of ferulic acid (3-methoxy-4-hydroxy-cinnamic acid) was found to be responsible for the development of the characteristic color in rice bran oil. The model reactions with the ferulate, iron and fatty acids could be suggested the mechanism.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.533-534
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• 2009

• Electrical & Electronic Materials
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• v.7 no.2
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• pp.100-106
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• 1994

A bilayer film consisting of a layer of a-Se$_{75}$ Ge$_{25}$ with a surface layer of silver -100[.angs.] thick and a monolayer film of a-Se$_{75}$ Ge$_{25}$ are irradiated with 9[keV] Ga$^{+}$ ion beam. The Ga$^{+}$ ion (10$^{16}$ [ions/cm$^{2}$] exposed a-Se$_{75}$ Ge$_{25}$ and Ag/a-Se$_{75}$ Ge$_{25}$ thin films show an increase in optical absorption, and the absorption edge on irradiation with shifts toward longer wavelength. The shift toward longer wavelength called a "darkening effect" is observed also in film exposure to optical radiation(4.5*10$^{20}$ [photons/cm$^{2}$]). The 0.3[eV] edge shift for ion irradiation films is about twice to that obtained on irradiation with photons. These large changes are primarily due to structural changes, which lead to high etch selectivity and high sensitivity.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.259-266
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• 2007

It has been proposed that the mode of action of nisin against vegetative cells and spores of Clostridium botulinum is different. However, clear explanation is not available. Therefore, nisin action against vegetative cells and spores of C. botulinum was investigated in this study. Nisin was added at various stages of spore-to-vegetative cell transition and changes to sensitivity to the bacteriocin were observed. Different nisin preparation (Nisaplin or pure nisin) was compared for their activity against different stages of spore transformation of C. botulinum ATCC 25763. Germination was measured by determining loss of heat resistance and observing phase darkening of spores under phase-contrast microscope. Nisin acted bactericidally against vegetative cells, but acted sporostatically against spores of C. botulinum under the same concentration. This bactericidal and sporostatic action of nisin was dependent on the concentration of nisin used. Presence of nisin during spore activation by heat increased subsequent phase darkening and germination rates. However, nisin inhibited the germination and the outgrowth, when it was added after heat activation stage. Findings from this study suggest that the time of addition of nisin is very important for the effective control of spores during the heating process of foods. In addition, it may be possible to apply nisin at the stage of processing that coincides with the most sensitive stage of spore transformation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.82-85
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• 1997

To develop an active material for skin darkening, we examined the effect of 300 plants on tyrosinase activity and found only Caesalpinia sappan has an ability to increase tyrosinase activity highly and melanin contents in B-16 melanoma cells. A compound increasing tyrosinase activity and melanin production was isolated from Caesalpinia sappan Lignum. Brazilin was identified as a new active agent. Brazilin increases the tyrosinase activity and malanin production of B-16 melanoma cells. In conclusion, it seems that brazilin cal be used as a new sunless tanning agent.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.264-265
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• 2003

광 회절한계를 극복한 기록밀도 향상 기술로 대두된 근접장 응용 정보저장기술은 차세대 광 정보저장의 핵심기술로 간주되고 있다. 근접장을 응용한 기술에는, 근접장 헤드구조의 관점에서, 근접장 효과 렌즈(SIL), 탐침형, 미소구멍레이저, 안테나 구조 등 나노크기 Aperture를 가지는 구조 등이 있다. 그러나 각각의 근접장 헤드구조에 적합한 특히, 탐침형 근접장 방식에 적합한 근접장 매체에 대한 활발한 연구는 아직 진행되고 있지 않다. (중략)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.435-440
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• 2002

In this study, we have investigated photo-induced changes of optical energy gap( $E_{OP)}$ and photoluminescence (PL) in amorphous ($\alpha$-) S $e_{100-x}$G $e_{x}$ (x=5, 25 and 33) thin films prepared by conventional thermal evaporation method. In the $\alpha$-S $e_{100-x}$G $e_{x}$ thin film, the $E_{OP}$ is obtained by a linear extrapolation of the ($\alpha$hν)$^{\frac{1}{2}}$ versus hν plot to the energy axis using the optical absorption coefficient ($\alpha$) calculated from the extinction coefficient k measured in the wavelength range of 290~900nm. Although the values of $\Delta$ $E_{OP}$ are very different, all films exhibit photo-induced photo-darkening (PD) effect that is a red shift of $E_{OP}$ . In particular, $\Delta$ $E_{OP}$ in $\alpha$-S $e_{75}$ G $e_{25}$ thin film exhibits the largest value (i, e., $\Delta$ $E^{OP}$ ~40meV for $\alpha$-S $e_{95}$ G $e_{5}$ , $\Delta$ $E_{OP}$ ~200meV for $\alpha$-S $e_{75}$ G $e_{25}$ , $\Delta$ $E_{OP}$ ~130meV for $\alpha$-S $e_{67}$ G $e_{33}$ ). PL spectra in $\alpha$-SeGe by hν$_{HeCd}$ have no-Stokes shift (SS) and show a tendency dependent on both composition and illumination time. We explain the energy-induced phenomena such as the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..tc..