• 제목/요약/키워드: light spectrum

검색결과 775건 처리시간 0.033초

Extraction of the atmospheric path radiance in relation to retrieval of ocean color information from the TM and SeaWiFS imageries

  • Ahn, Yu-Hwan;Shanmugam, P.
    • 한국GIS학회:학술대회논문집
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    • 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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    • pp.241-246
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    • 2004
  • The ocean signal that reaches the detector of an imaging system after multiple interactions with the atmospheric molecules and aerosols was retrieved from the total signal recorded at the top of the atmosphere (TOA). A simple method referred to as 'Path Extraction' applied to the Landsat-TM ocean imagery of turbid coastal water was compared with the conventional dark-pixel subtraction technique. The shape of the path-extracted water-leaving radiance spectrum resembled the radiance spectrum measured in-situ. The path-extraction was also extended to the SeaWiFS ocean color imagery and compared with the standard SeaWiFS atmospheric correction algorithm, which relays on the assumption of zero water leaving radiance at the two NIR wavebands (765 and 865nm). The path-extracted water-leaving radiance was good agreement with the measured radiance spectrum. In contrast, the standard SeaWiFS atmospheric correction algorithm led to essential underestimation of the water-leaving radiance in the blue-green part of the spectrum. The reason is that the assumption of zero water-leaving radiance at 755 and 865nm fails due to backscattering by suspended mineral particles. Therefore, the near infrared channels 765 and 865nm used fur deriving the aerosol information are no longer valid for turbid coastal waters. The path-extraction is identified as a simple and efficient method of extracting the path radiance largely introduced due to light interaction through the complex atmosphere carried several aerosol and gaseous components and at the air-sea interface.interface.

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아로니아 추출물에 의한 직물의 천연염색과 염액의 Spectrum 분석 (Analysis of naturally Dyed Textile Fabrics by using Aronia Extract)

  • 원아영;김종준
    • 패션비즈니스
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    • 제22권1호
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    • pp.124-134
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    • 2018
  • This study examined the dyeing characteristics and spectrum of cotton and silk by using dyeing solution extracted from aronia. The value $L^{\ast}$ which indicates the brightness of cotton regardless of mordant increases with increasing pH from pH 3.5 to pH 10.5. The color difference value(${\Delta}E$) of the cotton was generally high in pH 3.5 regardless of mordant existence. The silk showed the highest ${\Delta}E$ value in pH 3.5 dye solution as cotton did. On the other hand, the silk with mordant dyed showed the highest ${\Delta}E$ value in pH 7. Silk fabrics dyed with Aronia solution turns out red in pH 3.5, blue in pH 7 and yellow in pH 10.5. This is because of the amino acid, one of the silk ingredients, combines with a part of anthocyanin to show blue. As the result of the spectrum measurement, the maximum absorption wavelength of Aronia solution was increased in the order of pH 10.5, pH 3.5 and pH 7, regardless of extraction temperature and mordant. The measurement results of color fastness to washing and color fastness to light are generally low. Therefore, there is a need for further study to improve color fatness in the future.

2-밴드 모델을 이용한 발광다이오드의 발광 재결합계수에 대한 이론적 고찰 (A Study on the Radiative Recombination Coefficients based on the two band model in Light Emitting Diodes)

  • 김현성;심종인
    • 한국광학회:학술대회논문집
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    • 한국광학회 2008년도 동계학술발표회 논문집
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    • pp.365-366
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    • 2008
  • The spontaneous emission spectrum and the radiative recombination coefficient were analytically derived from the two band model for both the bulk (3-D) and the quantum well(2-D) structures of GaN-based Wurtzite crystal.

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Dynamic Quasi-Elastic Light Scattering Measurement of Biological Tissue

  • Youn, Jong-In;Lim, Do-Hyung
    • 대한의용생체공학회:의공학회지
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    • 제28권2호
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    • pp.169-173
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    • 2007
  • During laser irradiation, mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in accelerated stress relaxation. Clinically, laser-assisted cartilage reshaping may be used to recreate the underlying cartilaginous framework in structures such as ear, larynx, trachea, and nose. Therefore, research and identification of the biophysical transformations in cartilage accompanying laser heating are valuable to identify critical laser dosimetry and phase transformation of cartilage for many clinical applications. quasi-elastic light scattering was investigated using Ho : YAG laser $(\lambda=2.12{\mu}m\;;\;t_p\sim450{\mu}s)$ and Nd:YAG Laser $(\lambda=1.32{\mu}m\;;\;t_p\sim700{\mu}s)$ for heating sources and He : Ne $(\lambda=632.8nm)$ laser, high-power diode pumped laser $(\lambda=532nm)$, and Ti : $Al_2O_3$ femtosecond laser $(\lambda=850nm)$ for light scattering sources. A spectrometer and infrared radiometric sensor were used to monitor the backscattered light spectrum and transient temperature changes from cartilage following laser irradiation. Analysis of the optical, thermal, and quasi-elastic light scattering properties may indicate internal dynamics of proteoglycan movement within the cartilage framework during laser irradiation.

아르곤 레이저의 소아치과에서의 임상적 적용 (CLINICAL APPLICATION OF ARGON LASER IN PEDIATRIC DENTISTRY)

  • 이미나;이상훈;김종철
    • 대한소아치과학회지
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    • 제24권1호
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    • pp.139-147
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    • 1997
  • Argon laser used in this case report, is special in having two wavelength of 488, 514nm blue-green visible light spectrum. Blue light is used for composite resin polymerization and caries detection. Green light is used for soft tissue surgery and coagulation. Maximum absorption of this laser light occurs in red pigmentation such as hemoglobin. The argon laser may be well-suited for selective destruction of blood clots and hemangioma with minimal damage to adjacent tissues. Argon laser light penetrates tissue to the 1 mm depth, so its thermal intensity is lower than $CO_2$ laser light. Also, due to its short wavelength it can be focused in a small spot and even single gene can be excised by this laser and microscopy. After applicating argon laser to 4 patient for surgical procedure and to 1 patient for curing the composite resin, following results were obtained. 1. Improved visibility were gained due to hemostasis and no specific technique were needed according to easy recontouring of the tissue. 2. Ability to use by contact mode, tactile sense was superior but tissue dragability and accumulation of tissue on the tip needed sweeping motion. 3. Additive local anesthetic procedure was needed. 4. No suture and less curing time reduced chair time, this made argon laser available in pediatric dentistry.

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Screening and identification of bioorganic light-emitting substances from marine macrophytes

  • Jung, Sang Mok;Lee, Han Seong;Lee, Han Joo;Kang, Seul Gi;Son, Ji Su;Jeon, Jae Hyuk;Chae, Hee Baik;Shin, Hyun Woung
    • ALGAE
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    • 제30권2호
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    • pp.171-179
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    • 2015
  • Organic light-emitting materials in marine macrophytes from various coastal environments were identified. Twentyeight species from the solvent fractions were examined and identified as candidates for bioorganic light-emitting materials using photoluminescence (PL) spectra and gas chromatography-mass spectrometry. We selected 16 solvent fractions from a total of 1,221 prepared from Ishige okamurae, Sargassum confusum, Grateloupia elliptica, Chondracanthus intermedius, Porphyra yezoensis, Meristotheca papulosa, Gelidium amansii, and Scytosiphon lomentaria. The maximum light-emitting PL spectra appeared at various colors, mainly between blue and green, based on chromaticity coordinates, from solvent fractions of M. papulosa, G. amansii, G. elliptica, P. yezoensis, S. lomentaria, I. okamurae, and C. intermedius. These results will contribute to the development of novel organic light-emitting materials.

가시광선의 파장과 광도가 광중합형 복합레진의 경화에 미치는 영향 (THE EFFECTS OF WAVELENGTH AND INTENSITY OF VISIBLE LIGHT ON THE CURING OF VISIBLE LIGHT CURED COMPOSITE RESIN)

  • 이채경;허복
    • Restorative Dentistry and Endodontics
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    • 제14권1호
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    • pp.149-159
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    • 1989
  • The purpose of this study was to assess the effects of wavelength and intensity of light curing units on the curing of composite resin. The wavelength and intensity of nine units were evaluated with Optical Multichannel Analyzer and Radiometer. Two-part split stainless steel mold with a cylindrical hole-3.0mm in diameter, 6.0mm in hgieht-was prepared. After placing a Mylar strip between two parts, 100 specimens were made by inserting each of four composite resins into the mold and irradiating for 20 seconds with five light units alternatively. The curing depths were measured by scraping method and evaluated by two-way ANOVA. And Vicker's hardness measurements were made on the longitudinally sectioned surface at 0.5mm interval. The results were as follows: 1. Visilux 2 showed a narrow spectral band within the effective wavelength in initiating polymerization and the highest intensity. Translux showed the diffuse spectrum of wavelength and the lower light intensity. 2. Visilux 2 showed the highest curing effect in any composite resin and then followed by Optilux, Efos 35, Heliomat and Translux. (p < 0.01) 3. Durafill showed the deepest curing depth in any light unit and then followed by Bisfil M, Silux and Heliosit. (p < 0.01). 4. Maximum hardness values showed 0.1mm and 0.5mm under top surface and then gradually decreased with depth.

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Bleaching Herbicides의 제초활성에 영향을 미치는 온도 및 광의 영향 (Influences of Temperature and Light on the Herbicidal Activity of Bleaching Herbicides)

  • 김진석;나지영;조광연
    • 한국잡초학회지
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    • 제9권3호
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    • pp.230-237
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    • 1989
  • Bleaching herbicides(oxyfluorfen, oxadiazon, paraquat)의 작용발현에 영향을 미치는 온도 및 광의 효과를 조사한 결과 oxyfluorfen 과 oxadiazon의 제초활성은 $10-35^{\circ}C$에서 온도가 증가될수록 높았으며 온도의 효과는 제초작용 발현단계(photooxidation) 보다는 그 이전 단계에서 더욱 큰 영향이었다. 처리약제 모두 광도가 높을수록 활성이 강하였으며 paraquat 는 광질간의 활성차이가 없었으나 oxyfluorfen 및 oxadiazon 은 챙색광에서 높은 활성을 보였고 이들 두 약제에 대한 광의 효과는 광합성 및 호흡의 전자전달계나 carotenoid 생합성 보다는 chlorophyll 생합성 과정과 일정한 관련이 있다.

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가시오갈피 기내 식물체의 생장, 형태형성 및 eleutheroside 함량에 미치는 발광다이오드의 효과 (Effects of LED on Growth, Morphogenesis and Eleutheroside Contents of in vitro Cultured Plantlets of Eleutherococcus senticosus Maxim)

  • 정재훈;김영선;문흥규;황성진;최용의
    • 한국약용작물학회지
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    • 제17권1호
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    • pp.39-45
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    • 2009
  • The effects of red, blue, and far-red light by illumination of light emitting diodes (LEDs) on growth, morphogenesis and eleutheroside contents of in vitro plantlets of Eleutherococcus senticosus were examined. As a control, plantlets were grown under a broad spectrum white fluorescent lamp (16/8 h illumination). The length of plantlets grown under the red/blue LEDs was taller than those under fluorescent lamps. Leaf area, root length and fresh weight of plantlets were highest under blue light compared to other kinds of light sources. Chlorophyll contents in plantlets grown under fluorescent lamps were higher than those in plantlets grown under LED illumination. Production of eleuthroside B and E in plantlets was highest under blue LED. However, production of eleuthroside E1 was highest under fluorescent lamps. These results suggest that plant growth and eleuthroside accumulation can be controlled by wave length of light under LED illumination system.

외부광잡음에 의한 실내외 가시광 무선통신 성능 변화 분석 (Performance Analysis of Indoor/Outdoor Visible Light Communication System Influenced by External Noise Light)

  • 양세훈;김덕래;김현승;손용환;한상국
    • 한국통신학회논문지
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    • 제36권12B호
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    • pp.1595-1600
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    • 2011
  • IM/DD 방식을 이용한 가시광 무선 통신의 성능 저하를 발생시키는 인공광과 태양광에 의한 잡음 레벨을 분석하였다. 통신 성능을 확인하기 위해 LED에 QPSK로 변조된 50ksymbol/sec의 신호를 2MHz의 부반송파에 전송하였으며 PD를 통해 수신된 신호의 EVM과 스펙트럼을 분석하였다. 또한 차광막을 이용하여 신호의 성능을 향상시켰으며 이를 통해 IM/DD방식으로 실외 가시광 통신이 가능함을 확인하였다.