• Title/Summary/Keyword: Sun Light

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Effect of Growth Retardants on the Growth of Periila fuetescens var. acuta (차즈기(Perilla frutescens var. acuta)의 생육에 미치는 생장억제제의 영향)

  • Lee, Jong-Suk;Park, Young-Min
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.2
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    • pp.1-11
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    • 2004
  • The purpose of this study was to determine usability as potted flowers and garden plants by controlled plant height using growth retardants. There was no significant difference on the dwarfing effect according to the degree of exposure the sun, but growth was well under full exposure to the sun. The plant height was decreased by application of Cycocel (CCC), Bonzi (paclobutrzol), Ancymidol, and Uniconazole compared to the control group, and treatment of Bonzi $5mg{\cdot}L^{-1}$ was most dwarfing effect for both full sun exposure or 70% controlled shading condition. No consistent different was found in stem diameter, leaf color change, the content of chlorophyll and anthocyanin when the concentration of plant growth retardants was altered. These factors were affected only by light intensity. In comparison to the results of the control group, leaf length, leaf width, plant width and petiole length were all reduced by the application of growth retardants.

Comparison of reproducibility of prepared tooth impression scanning utilized with white and blue light scanners (백색광과 청색광 스캐너를 이용한 지대치 인상체 스캐닝의 반복재현성 비교)

  • Jeon, Jin-Hun;Sung, Hwan-Kyung;Min, Byung-Kuk;Hwang, Jae-Sun;Kim, Ji-Hwan;Kim, Woong-Chul
    • Journal of Technologic Dentistry
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    • v.37 no.4
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    • pp.213-218
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    • 2015
  • Purpose: The purpose of this study compared of reproducibility of prepared tooth impression scanning utilized with white and blue light scanners. Methods: To evaluate reproducibility with white and blue light scanners, the impression of premolar were rotated by $10^{\circ}{\sim}20^{\circ}$ and scanned. These data were compared with the first 3-D data (STL file), and the error sizes were measured (n=5). Independent t test was used to evaluation the reproducibility of impression of premolar with white versus blue light scanners through discrepancies of mean, RMS (${\alpha}=0.05$). Results: Discrepancies of mean with regard to reproducibility were $11.2{\mu}m$, $5.8{\mu}m$, respectively, with white and blue light scanners (p<0.047). And discrepancies of RMS with regard to reproducibility were $33.4{\mu}m$, $18.8{\mu}m$, respectively, with white and blue light scanners (p<0.045). Conclusion: Our results indicate a good reproducibility of prepared tooth impression digitized with blue light scanner more than that with white light scanner.

Measurements and characterizations of cerenkov light in fiber-optic radiation sensor irradiated by high energy electron beam (고에너지 전자선 측정을 위한 광섬유 방사선 센서에서의 체렌코프 빛 측정 및 분석)

  • Jang, Kyoung-Won;Cho, Dong-Hyun;Jeong, Sun-Cheol;Jun, Jae-Hun;Lee, Bong-Soo;Kim, Sin;Cho, Hyo-Sung;Park, Sung-Yong;Shin, Dong-Ho
    • Journal of Sensor Science and Technology
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    • v.15 no.3
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    • pp.186-191
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    • 2006
  • In general, Cerenkov light is produced by a charged particle that passes through a medium with a velocity greater than that of visible light. Although the wavelength of Cerenkov light is very broad, the peak is in the almost visible range from 400 to 480 nm. Therefore, it always causes a problem to detect a real light signal that is generated in the scintillator on the fiber-optic sensor tip for dose measurements of high-energy electron beam. The objectives of this study are to measure, characterize and remove Cerenkov light generated in a fiber-optic radiation sensor tip to detect a real light signal from the scintillator. In this study, the intensity of Cerenkov light is measured and characterized as a function of incident angle of electron beam from a LINAC, and as a function of the energy of electron beam. As a measuring device, a photodiode-amplifier system is used, and a subtraction method using a background optical fiber is investigated to remove Cerenkov light.

Real-time Soft-shadow using Shadow Atlas (그림자 아틀라스를 이용한 부드러운 그림자 생성 방법)

  • Park, Sun-Yong;Yang, Jin-Suk;Oh, Kyoung-Su
    • Journal of the Korea Computer Graphics Society
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    • v.17 no.2
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    • pp.11-16
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    • 2011
  • In computer graphics, shadows play a very important role as a hint of inter-object distance as well as themselves in terms of realism. To represent shadows, some traditional methods such as shadow mapping and shadow volume have been frequently used for the purpose. However, the rendering results are not natural since they assume the point light. On the contrary, an area light can render soft-shadows, but its computation is too burdensome due to integral over the whole light source surface. Many alternatives have been introduced, back-projection of occluder onto the light source to get visibility of light or filtering of shadow boundary by calculating size of penumbra. But they also have problems of light bleeding or ringing effects because of low order approximation, or low performance. In this paper, we describe a method to improve those problems using shadow atlas.