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        검색결과 11

        1.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국제 해상교통량 및 물동량이 증가함에 따라 한반도 주변해역의 선박유동량도 늘어나고 있으며 이에 따라 크고 작은 항구가 위치하고 있는 남해에서의 해양 사고도 꾸준히 발생하고 있다. 특히 선박간의 충돌 및 침몰 사고는 인적 및 물적 피해뿐만 아니라 해양환경오염을 유발하기 때문에 광역의 범위를 고해상도로 볼 수 있는 인공위성을 통한 신속한 선박탐지가 필요하다. 본 연구에서는 광학 인공위성 아리랑 2호 관측자료를 활용하여 광양만 인근해역의 각 채널 별 반사도 값을 비교 분석하여 새로운 선박탐지지수를 제시하였다. 선박 분류를 위해 그 선박탐지지수의 역치를 0.1로 설정하였고, RGB 합성영상과 비교하였을 때 대다수의 선박을 탐지하였음을 보여주었다. 연구해역에 포함되어 있는 큰 규모의 선박을 선정 후, 선박 주변의 공간적 반사도 분포를 분석하였다. 그 결과 선박 북서방향에 위치한 균일한 형태의 선박그림자를 확인할 수 있었다. 이는 태양의 위치가 남동방향에 위치하고 있음을 나타내고 있으며, 실제 위성영상이 촬영된 시기의 방위각은 144.80o로 영상내의 그림자의 위치를 통해 태양의 방위각을 유추할 수 있다. 그림자의 반사도는 주변 바다 및 선박에 비해 낮은 0.005 값을 나타냈고, 선수 및 선미에 따라 높이차가 달라짐을 보였다. 이는 선박의 갑판 및 구조물의 높이를 반영한 것으로 판단된다. 본 연구 결과는 연안 해상사고 발생 시 실종선박 수색기술에 고해상도 광학 인공위성 영상이 활용될 수 있음에 의의가 있다.
        4,000원
        6.
        2013.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We demonstrate optical cross-sectional imaging system implemented with high-resolution interferometry and present oral diagnostic imaging results obtained without any physical sectioning. High-resolution interferometry could be performed with utilizing broadband optical source and employment of beam scanning device to high-resolution interferometer constitutes optical imaging system for non-invasive cross-sectional view at real-time. The optical imaging system is implemented with fiber-optic devices for compactness and optical probe head is realized by using single mode optical fiber and miniaturized actuator, which is properly designed for the application to dental imaging. The basic performance of the optical imaging system, for example, such as resolution, imaging depth, and sensitivity is suggested to prove high-resolution optical imaging performance. Feasibility of the developed optical imaging system performance in the application of dental diagnostic is proved with demonstrating non-invasively obtained cross-sectional images. The imaging quality suggested in the images could be applied to assessment of oral diseases and used for alternative imaging modality to X-ray diagnostic method overcoming disadvantage of low-image resolution. The imaging performance enabling real-time image reconstruction also could be exploited as early oral diagnostic apparatus prior to microscopic observation under H&E staining.
        4,300원
        7.
        2011.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the results of our high resolution optical spectroscopic monitoring campaign (⋋ = 3800 ~ 8800 Å, R = 30000 - 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between November 26 and December 29, 2010, and FU Orionis itself on January 26, 2011. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 Å. We resolve the Hα and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and red-shifted broad features.
        4,000원
        9.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The results of the Crab pulsar observations with the photometrical MANIA (Multichannel Analysis of Nanosecond Intensity Alterations) complex at the 6-m telescope are presented. More than 12 millions photons in UBVR-bands simultaneously with time resolution of 10-7s were detected. Using the original software for search for optical pulsar period, we obtained the light curves of the object with time resolution of about 3.3 μs. Their detailed analysis gives the spectral change during pulse and subpulse, the shape of the pulse peaks, which are plateaus (with the duration of about 50 μs for the main pulse), limits for an amplitude of fine temporal (stochastic and regular) structure of pulse and sub pulse and the interpulse space intensity. The results of CCD-spectroscopy of the Crab pulsar show that its summarized spectrum is flat. There are no lines, neither emission nor absorbtion ones. Upper limit for line intensity or depth is 3.5% with the confidence probability of 95%.
        10.
        1990.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-l,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.Optical resolution of aminoalcohols had been achived efficiently by use of (R)-2,2'-dihydroxy-1,1'-binaphtholphosphoric acid as the resolving agent in various organic solvents. Racemic aminoalcohols were resolved very easily and high enantiomer yield (about 70% e,e) in THF. On the other hand, absolute configuration of resolved aminoalcohol was (R)-configuration but one of the Valinnol and Phhenylglycinol was anti-type because of sterichindrance.
        4,000원
        11.
        2012.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Observations with milliarsecond resolution using the Navy Optical Interferometer have been obtained for a number of stellar systems which include high-mass binaries, eclipsing binaries, and radio stars. These observations also reveal the previously unseen companions in single-lined spectroscopic binaries via directly measured flux ratios. We will present examples of published and ongoing research efforts of these systems to illustrate how an optical interferometer contrib\-utes to our knowledge of stars, their environment, and companions. These studies include a conclusive revealing of the previously unseen companion in the single-lined binary Φ Herculis, the direct determination of orbital parameters in the wide and close orbits of Algol, and revealing the orbit of β Lyrae with spatially resolved images of the Hα emission.