• Title/Summary/Keyword: ultraviolet light

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Ultraviolet Spectrophotometry of VV Cephei

  • Kang, Young-Woon
    • Bulletin of the Korean Space Science Society
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    • 1992.10a
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    • pp.14-14
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    • 1992
  • The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately30,OOOK, based en the flux distributions durstributions during egress, Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350A,2550A and :!850A have been analyzed by the modified Wilson and Oevinney light curve program. the radii of the B star and M star were deduced to 0.05 and 0.22 of uint separation, respectively. The UV light curves show anevidence that the light was attenuated by the highly opaque atmosphere of the M star

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ULTRAVIOLET SPECTROPHOTOMETRY OF VV CEPHEI

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.9 no.1
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    • pp.111-119
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    • 1992
  • The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350 ${\AA}$, 2550 ${\AA}$ and 2850 ${\AA}$ have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atmosphere of the M star.

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Circuit Design of Ultraviolet Flame-Sensor for Fire-Fighting Appliances (자외선 센서를 이용한 화재감지기 응용 회로 설계)

  • Kim, Yeong-Min;Kim, Jong-Man
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.1-5
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    • 2008
  • In this paper, we proposed that when combustible burn with ultraviolet radiation, introduce fire detector with sensor of private-use detectable light energy as ultraviolet in energy of electromagnetic-wave type radiate from flame. This research using ultraviolet flame sensor is pyro-electric ultraviolet sensor based black body radiation theory. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV flame detector and proposed method of false alarm reduced to resemble fire. the result proposed the prevention and extinction of fire technique degree, certificated operation of detector.

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Enhanced Photocatalytic Activity of 3,4,9,10-Perylenetetracarboxylic Diimide Modified Titanium Dioxide Under Visible Light Irradiation

  • Kim, Ji-Won;Kim, Hee-Sung;Yu, Kook-Hyun;Fujishima, Akira;Kim, Young-Soon
    • Bulletin of the Korean Chemical Society
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    • v.31 no.10
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    • pp.2849-2853
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    • 2010
  • A method to improve the photocatalytic activity of titanium dioxide by modification with a sensitizer and a metal oxide is proposed. To achieve this goal, we used metal oxides as dopants. In particular, $CaWO_4$ and $Gd_2O_2S$:Tb were used because their 2.6 eV and 2.2 eV band gap energy and optical properties have a large positive effect on photocatalysis. The improvement in the photocatalytic activity of $TiO_2$ modified with $Gd_2O_2S$:Tb under ultraviolet light irradiation is described in a previous study. The present work focuses on the sensitization of metal oxide-modified $TiO_2$. Having observed the ultraviolet-visible absorption spectra of 3,4,9,10-Perylenetetracarboxylic diimide in the wide visible-light region from 400 nm to 650 nm and the broad peaks in its photoluminescence spectra at 695 nm and 717 nm, we decided to use this perylene dye to sensitize modified $TiO_2$ to enhance its activity as a visible-light harvesting photocatalyst. We also explored the positive effects thin-film surface changes stemming from ultraviolet pre-treatment have on photocatalytic activity. Finally, we subjected several metal oxide-modified $TiO_2$ products sensitized by the perylene dye to ultraviolet pre-treatment, obtaining the most active photocatalysts.

p-n heterojunction composed of n-ZnO/p-Zn-doped InP (n-ZnO/p-Zn doped InP의 p-n 이종접합 형성에 관한 연구)

  • Shim, Eun-Sub;Kang, Hong-Seong;Kang, Jeong-Seok;Bang, Seong-Sik;Lee, Sang-Yeol
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.126-129
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    • 2001
  • A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

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p-n Heterojunction Composed of n-ZnO/p-Zn-doped InP

  • Shim, Eun-Sub;Kang, Hong-Seong;Kang, Jeong-Seok;Pang, Seong-Sik;Lee, Sang-Yeol
    • Transactions on Electrical and Electronic Materials
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    • v.3 no.1
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    • pp.1-3
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    • 2002
  • A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed typical I-V characteristics. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

p-n heterojunction composed of n-ZnO/p-Zn-doped InP (n-ZnO/p-Zn doped InP의 p-n 이종접합 형성에 관한 연구)

  • 심은섭;강홍성;강정석;방성식;이상렬
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.126-129
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    • 2001
  • A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process ws performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

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Development and Efficiency-Stabilization of UV Blocking Agents Used to Skincare (피부 미용에 있어서 자외선 차단제의 개발 및 유효 안전성)

  • Kim, S.C.;Nam, K.D.;Lee, H.W.
    • Journal of the Korean Applied Science and Technology
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    • v.12 no.2
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    • pp.157-163
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    • 1995
  • The ultraviolet blocking agents used to skincare are largely classified ultraviolet scattering agent and ultraviolet absorbent agents. There are UVC, UVB, and UBA in ultraviolet ray(UV) showing shorter wavelength than visible light. Both visible light and UVA give rise to 1st dark-skinned phenomena. On exposure of the skin to UV, phenomena of skin variation are termed sunburn or suntan. There are chronic and acute adverse reactions in skin response to UV. The latter is caused by UVB, which has mainly effects on the skin. But lately due to destruction of ozone layer, UVA has more serious irritation on the skin than UVB. In this paper spectrometric properties of UV absorbent agents such as PABA, octyl-PABA, Urocanic acid, and 2-hydroxy-4-methoxy benzophenone in vitro have been investigate. As results, it was found that the three fomer were more suitable than the last. UV scattering measurements on the sample used inorganic pigments showed that pigments containing titanium dioxide had a better scattering effects than the inorganic pigments such as $Fe_2O_3$, $Al_2O_3$, etc.

Introduction of Ultraviolet/Infrared Flame Detector and Method for False Detection Prevention (자외선/적외선 불꽃감지기 소개 및 오동작 방지를 위한 연구)

  • Lim, Byung-Hyun;Ko, Nak-Yong;Hwang, Jong-Sun;Kim, Yeong-Min;Kim, Jong-Man
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05b
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    • pp.8-11
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    • 2003
  • We propose that when combustible burn with contain carbon, introduce fire detector with sensor of private-use detectable light energy as infrared and ultraviolet in energy of electromagnetic-wave type radiate from flame, method for correct discrimination to resemble fire produce false alarm of detector such as sun light, hot object radiation, are welding. This research using infrared sensor is pyroelectric infrared sensor based black body radiation theory. 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 introduced UV/IR compound type flame detector and proposed method of false alarm reduced to resemble fire. The result propres the prevention and extinction of fire technique degree, certificated operation of detector.

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