• Journal of Korean Society for Atmospheric Environment
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• v.24 no.E2
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• pp.74-82
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• 2008

We have examined seasonal and annual means of clear-sky solar noon and daily erythemal ultraviolet-B irradiances measured in Anmyeon. The intensity of the EUV-B irradiance is mainly dependent on solar zenith angle (SZA) and total ozone amounts on clear day conditions. The daily maximum occurs near solar noon time and the highest monthly accumulated EUV-B is seen in July in Anmyeon. The maximum daily variation occurs in June and July due to precipitation and clouds. The 7-year trend of EUV-B irradiance shows that it is slightly increasing. Additionally, we could confirm that aerosol effects such as Asian Dust decreases the EUV-B irradiance reaching the ground surface by 35% to 60%. For more than 45% of the summer days, EUV-B irradiacne was high enough that the UV index registered higher than category Extremely High. This information will be very important for evaluation of the UV index for prevention of both skin cancer and ecosystem damages as well as to understand UV climatology over the Korean Peninsula.

• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.321-333
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• 1998

In order to derive the UV color - effective temperature relation, we calculated the effective temperature and ultraviolet color index for about 118 IUE standard stars. Using differential correction method, the effective temperature was obtained by the best fittings of IUE low-dispersion spectra to the Kurucz model (1993), and the UV color index was calculated from the magnitude differences of the UV wavelength between 2750 $\AA$ and 2950 $\AA$. The temperature determined by the Kurucz model fittings was consistent with that obtained by other investigators (Malagnini & Morossi 1990, Malagnini et al. 1986), except for the low temperature stars. The relations between UV color - effective temperature also was similar to that in Kurucz model.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.2
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• pp.223-233
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• 2006

We analyzed the monthly and seasonal mean of the daily Erythemal Ultraviolet-B (EUV-B, $280{\sim}320nm$) irradiance operating in Pohang, Anmyeon, Gosan, Mokpo and Kangnung with UV-Biometer (Solar Light Co., Model No. 501) at clear-sky noon during the period from 1999 to 2004. Also, we investigated the seasonal and regional characteristics for the UV index over the Korean Peninsula. The daily maximum occurred near solar southing time and the highest monthly accumulated EUV-B irradiance appeared in July and August at each regional observatory. The monthly mean value of the clear-sky EUV-B irradiance in Pohang, Anmyeon, Gosan, Mokpo and Kangnung showed 196.6, 161.8, 221.9, $171.5mWm^{-2}\;and\;179.7mWm^{-2}$ near noon in July respectively. The annual mean value of the daily accumulated EUV-B irradiance in Pohang, Anmyeon, Gosan, Mokpo and Kangnung were 1.8, 2.1, 2.2, $1.8kJm^{-2}\;and\;1.5kJm^{-2}$ respectively. The UV Index (UVI) showed above UVI 7(High) more than 90 days during one year over the Korean Peninsula.

• Journal of Life Science
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• v.8 no.3
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• pp.272-278
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• 1998

To investigate the effects of different UV-B levels on plant growth, cucumber plants were subjected to three levels of biologically effective ultraviolet-B(UV--$B^{BE}$ radiation [daily dose : 0.03(No UV-B), 6.40(Low UV-B) and 11.30 (High UV-B) kJ $m^{-2}$, UV--$B^{BE}$] in the growth chambers for 3 weeks during the early growth period. High and low levels of UV-B irradiation drastically decreased both dry weight and leaf area, but increased specific leaf weight of cucumber. Plants subjected to UV-B resulted in 30% and 20% reduction of photosynthesis rate by high and low UV-B, respectively. However, respiration rate was not affected by the UV-B. With increasing UV-B intensity, total chlorophyll contents were decreased linearly, while the contents of flavonoid were increased linearly. These results suggest that the present levels of UV-B may affect the growth of cucumber plant compared with a UV-B-free condition. It is likely that the growth of cucumber will be affected by enhanced UV-B due to ozone depletion in the near future.

• Biomedical Science Letters
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• v.12 no.4
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• pp.349-354
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• 2006

Induction of apoptosis allows the organism to get rid of abnormal cells and also of tumor cells. Understanding the mechanism involved in Ultraviolet radiation (UV) induced apoptosis may improve its therapeutic efficacy. In this study, we present expression of poly (ADP-ribose) polymerase (PARP) during apoptosis induced by UV in HeLa $S_3$ cells. Four different assays were performed in this study: morphological assessment of apoptotic cells and cell viability, DNA fragmentation analysis by agarose gel electrophoresis, quantitative assay of fragmented DNA, and expression of PARP by the western blot analysis. The percentages of apoptotic HeLa $S_3$ cells irradiated with $75J/m^2$ UV was increased continuously from 3 hrs incubation. DNA ladder pattern was appeared at 6 hrs. The amount of nucleosomal DNA fragments in cells treated UV increased from 3 to 12 hrs incubation and gradually decreased. The cleavage of PARP in HeLa $S_3$ cells irradiated with UV was induced, and the cleavage of PARP was more delayed in the cells pretreated with $5J/m^2$ UV and subsequently irradiated with $75J/m^2$ UV. than that in the cells only irradiated with $75J/m^2$ UV. Thus these data suggest that the cleavage of PARP relates with DNA fragmentation associated with apoptosis.

• Animal cells and systems
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• v.1 no.4
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• pp.637-640
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• 1997

Raf-1, a cytoplasmic serine/threonine protein kinase, serves as a central intermediate in many signaling pathways in cell proliferation, differentiation, and development. In this study, we investigated that B-raf, Drosophila homolog of the human c-raf-1, is involved in ultraviolet (UV) responsive events by using hypomorphic mutant $D-raf^{c110}$ and Draf-lacZ transgenic fly. At first, effect of UV damage on the survival of wild-type and $D-raf^{C110}$ strains was examined. In terms of $1/LD_{50}$ value, the relative ratio of UV sensitivities of wild-type versus $D-raf^{C110}$ strain was 1 : 2.2. By using quantitative $\beta$-galactosidase activity analysis, transcriptional activity of the D-raf gene promoter was also examined in UV-irradiated Draf-lacZ transgenic larvae. UV irradiation increased the expression of lacZ reporter gene in Draf-lacZ transgenic fly. However, in $D-raf^{C110}$ strain the transcriptional activity of D-raf gene promoter by UV irradiation was extensively reduced. Results obtained in this study suggest that D-raf plays a role in UV response, leading to better survival of Drosophila to UV damage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.62-65
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• 2005

We studied the nematic liquid crystal (NLC) alignment capability by the Ultraviolet (UV) alignment method on a-C:H thin-films, and investigated electro-optical performances of the UV aligned twisted nematic (TN)-liquid crystal display (LCD) with the UV exposure on a-C:H thin film surface. A good LC alignment by UV irradiation on a-C:H thin-film surfaces was achieved. Monodomain alignment of the UV aligned TN-LCD can be observed. The good electro-optical (EO) characteristics of the UV aligned TN-LCD was observed with oblique UV exposure on the a-C:H thin film surface for 1min.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.295-298
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• 2001

This paper presents mechanical properties and weatherability of FRP pole used for a distribution line about high strength and good insulation properties. The experiment strength obtained in cantilever beam test are comparable to ES standards. The environmental factors, such as elevated temperatures, high humidity, and corrosive fluids, and ultraviolet(UV) rays, influence on the performance of Polymeric matrix composite.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.135-142
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• 2010

To investigate the effects of ultraviolet(UV-B) on growth and biochemical defense responses of plant, garden balsam (Impatiens balsamina L.) was subjected to enhanced UV-B irradiation [daily dose: 0.02 (No UV-B) and 11.34 (enhanced UV-B) kJ $m^{-2}$ ; $UV-B_{BE}$] for 3 weeks. Enhanced UV-B drastically inhibited leaf area as well as dry weight of garden balsam. The content of malondialdehyde was significantly increased by about 50% after 3 weeks of UV-B irradiation. The ratios of dehydroascorbate/ascorbate and oxidized glutathione/reduced glutathione were also considerably increased by UV-B irradiation. Three major polyamines of garden balsam leaves: putrescine, spermidine and spermine were observed. All polyamine contents were increased with UV-B irradiation. The enzyme (superoxide dismutase, ascorbate peroxidase etc.) activities of garden balsam were increased by the UV-B enhancement. Based on the results, enhanced UV-B caused oxidative stress in garden balsam and biochemical protection responses might be activated to prevent from damaging effects of oxidative stress generated by UV-B irradiation.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.5 s.164
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• pp.659-669
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• 2007

The purpose of this study was to investigate the degradation of silk fabrics dyed with gardenia and sappanwood by Ultraviolet Light(UV). To asses the effect of uv on dyed silk fabrics, physical and chemical properties of samples were explored. K/S value rapidly decreased with increasing exposure time. Mordanting improved ultraviolet-cut ability and the sappanwood dyed samples were superior to those of gardenia dyed in ultraviolet-cut ability. Color progressively faded away as uv exposure time increased, accordingly, $L^*,\;a^*,\;b^*$, H/VC, ${\Delta}E$ were changed. Morphological change observed with SEM represented degradation of silk fabrics from the outer fibril to the inner fibril. Tensile Strength abruptly decreased as uv exposure time increased and the mordanted samples showed higher tensile strength than the unmordanted. FT-IR analysis confirmed that main peaks at 3297 and $1704cm^{-1}$ band for silk fabric were due to N-H and C=O stretching, gardenia peaks at 1654 and $668cm^{-1}$ band representing C=O(ester), C=C(alken) and O-C=O(carboxylic acids) of crocin and sappanwood peaks at $1715cm^{-1}$ band representing C=O(cyclic keton) of brazilin appeared on the samples exposed for 14 days, but these peaks indicating colorants after 28 days of uv exposure faded away due to prolonged exposure of uv.