• Title, Summary, Keyword: UV (ultraviolet) light

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Harmful Effects of UV Light on the Skin (피부에 대한 자외선의 유해작용)

  • 안병길
    • Proceedings of the SCSK Conference
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    • pp.69-78
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    • 1992
  • It is well hewn that ultraviolet light(UV) penetrates into the skin depends on the wavelength and causes many biochemical reactions in the skin. The enormous amount of information reveals that UV effects sun-burn, sun-tan and photoaging etc. In addition to these, it is now recognized that UV initiates immuno-suppression, and associated with this, skin cancer. In this review, I tried to illuminate the processes of injurious effects of UV on the skin.

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Effects of Ultraviolet-B Radiation on Photosynthesis in Tobacco (Nicotiana tabacum cv. Petit Havana SR1) Leaves (자외선-B 스트레스에 대한 담배 잎의 광합성 능의 변화)

  • Lee, Hae-Youn;Park, Youn-Il;Hong, Young-Nam
    • Korean Journal of Environmental Agriculture
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    • v.26 no.3
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    • pp.239-245
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    • 2007
  • The effect of ultraviolet-B (UV-B) radiation on photosynthesis was studied by the simultaneous measurements of $O_2$ evolution and chlorophyll (Chl) fluorescence in tobacco leaves. When the tobacco leaves were teated with UV-B (1 $W{\cdot}m^{-2}$), the maximal photosynthetic $O_2$, evolution (Pmax; 4.60 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) was decreased with increasing time of UV-B treatment showing 80% decline after 4 h treatment. Chl fluorescence parameters were also affected by ultraviolet-B. Fo was increased while both Fm and Fv were decreased, resulted in the decreased of photochemical efficiency of PSII (Fv/Fm). Non-radiative dissipation of absorbed light as heat as estimated as NPQ (Fm/Fm' - 1) was also decreased with increasing time of UV-B treatment while the extent of photochemical quenching (qP) was not changed. Thus, the ratio of (1-qP)/NPQ parameter was also increased with increasing time of UV-B treatment indicating PSII is under the threat of photoinhibition. The result indicate that UV-B primarily decreases the capacity to dissipate excitation energy by trans-thylakoid pH, which in turn inhibits PSII activity.

ULTRAVIOLET FLUX VARIATION OF EPSILON AURIGAE

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.7 no.1
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    • pp.57-69
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    • 1990
  • The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 $AA$ to 3050 $AA$. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

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A study on the polarized spectacle lens with photochromic UV blocking function of refractive index 1.60 (굴절률 1.60 광변색성 자외선 차단기능을 갖는 편광안경렌즈 연구)

  • Han, Doo-Hee
    • Journal of Convergence for Information Technology
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    • v.8 no.1
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    • pp.147-152
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    • 2018
  • A polarizing spectacle lens having a perfect blocking of ultraviolet light and a partial blocking of blue light and having photochromic properties has been developed. It is a functional spectacle lens which can be used as a spectacle lens in the daytime, which plays a role of sunglass in a space with strong ultraviolet rays, dramatically reducing glare caused by late-night driving or reflected light. Photochromism was recovered in 0.5 second dark reaction and 3 seconds recovery time. The polarization function was about 95%. Ultraviolet rays were completely blocked and blue light was reduced by about 30%. A lens that combines photochromic and UV blocking and polarization functions is the first attempt at investigating the domestic market.

Transmission of Solar Light according the Relative CDOM Concentration of the Sea-ice-covered Pacific Arctic Ocean (태평양 북극 결빙 해역 내 유색 용존 유기물 CDOM 분포에 따른 태양광 투과 비교)

  • Kang, Sung-Ho;Kim, Hyun-Choel;Ha, Sun-Yong
    • Ocean and Polar Research
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    • v.40 no.4
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    • pp.281-288
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    • 2018
  • The transmission of solar light according to the distribution of chromophoric dissolved organic matter (CDOM) was measured in the Pacific Arctic Ocean. The Research Vessel Araon visited the ice-covered East Siberian and Chukchi Seas in August 2016. In the Arctic, solar [ultraviolet-A (UV-A), ultraviolet-B (UV-B), and photosynthetically active radiation (PAR)] radiation reaching the surface of the ocean is primarily protected by the distribution of sea ice. The transmission of solar light in the ocean is controlled by sea ice and dissolved organic matter, such as CDOM. The concentration of CDOM is the major factor controlling the penetration depth of UV radiation into the ocean. The relative CDOM concentration of surface sea water was higher in the East Siberian Sea than in the Chukchi Sea. Due to the distribution of CDOM, the penetration depth of solar light in the East Siberian Sea (UV-B, $9{\pm}2m$; UV-A, $13{\pm}2m$; PAR, $36{\pm}4m$) was lower than in the Chukchi Sea (UV-B, $15{\pm}3m$; UV-A, $22{\pm}3m$; PAR, $49{\pm}3m$). Accelerated global warming and the rapid decrease of sea ice in the Arctic have resulted in marine organisms being exposed to increased harmful UV radiation. With changes in sea ice covered areas and concentrations of dissolved organic matter in the Arctic Ocean, marine ecosystems that consist of a variety of species from primary producers to high-trophic-level organisms will be directly or indirectly affected by solar UV radiation.

WTP UV Disinfection System (국내하수처리장 자외선소독조 운영실태 및 기술동향)

  • Lee, J.Y.;Kim, Y.T.;Lee, T.J.
    • 유체기계공업학회:학술대회논문집
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    • pp.126-132
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    • 2005
  • UV disinfection system allows the disinfection of municipal and industrial water and wastewater without the use of expensive chlorination and dechlorination techniques, labor intensive equipments In traditional ultraviolet systems the UV lamps are seperated from water by quartz sleeves. quartz is one of. the few materials that is virtually transparent to UV light, the UV lamp is placed inside the Quartz sleeve. UV light from the lamp is passed through the quartz and into the water, thereby providing disinfection. In fluoropolymer tube-used non-contact UV systems, the water flows through fluoropolymer plastic tubes. banks of UV lamps surround these tubes such that each tube gets exposed to ultra violet light from all sides. in non-contact design the lamps operates at almost constant temperature. this design is extremly efficient in the utilization of UV energy and superior to conventional contact- systems.

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Degradation of Natural Dyed Silk Fabrics under Ultraviolet Light(UV) -Focused on Gardenia and Sappanwood- (자외선에 의한 천연 염색 견직물의 취화 연구 -치자, 소목 염색을 중심으로-)

  • Shin, Youn-Sook;Choi, Seung-Youn
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.5
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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.

A Water Tap Equipped with a Sterlization/Purification System of Non-contact UV-lamp (비접촉식 자외선램프를 이용한 살균/정화 수도꼭지)

  • Min, Kyoung-Won;Won, Jong-Heon;Lee, Hyun-Cheol;Han, Dong-Youl
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.3-7
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    • 2007
  • Ultraviolet light(UV-C, wavelength: 200~280nm) is employed profitably for sterilizing drinking water. For most water serving apparatus such as a water purifier, a water cooler and heater, a coffee vending machine and etc., pre-sterilized water may be contaminated secondarily with bacillary inhabitation in a container before serving. In consideration of this problem, a household water tap which is equipped with a sterilization/Purification device in combination with non-contact UV-lamp, was designed to sterilize and purify water at the last outlet just before serving. Hopefully this simple but creative item may be commercialized for household and public use.

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Driving Method of Ultraviolet Sensor for Fire alarms using Pulse Width Modulation (PWM을 이용한 화재 감지를 위한 자외선 센서의 구동 방법)

  • Lim, Byung-Hyun;Ko, Nak-Yong;Hwang, Jong-Sun;Kim, Yeong-Min
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.31-35
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    • 2004
  • We propose driving method of Ultraviolet sensor for fire alarms using pulse width modulation that used to fire detector with sensor of private-use detectable light energy as ultraviolet in energy of electromagnetic-wave type radiate from flame, when combustible burn with contain carbon,. Ultraviolet sensor is UV Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research designed driving circuit with UV sensors and proposed method of false alarm reduced to resemble fire. the result propers the prevention and extinction of fire technique degree, certificated operation of detector.

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