• 한국결정성장학회지
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• 제15권3호
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• pp.114-119
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• 2005

This study has been carried out with the eight HPHT processed NOUV diamonds - two yellow, two yellowish green, two green and two orangy yellow color stones. The gemological properties of these diamonds included a highly saturated body color, graphitized fractures around the girdles, tension cracks around crystalline inclusions, long-wave UV with medium yellowish green to a very strong yellowish green luminescence, and short-wave UV with faint yellowish green to a strong yellowish green luminescence. Distinctive features of spectroscopic properties include absorption peaks at 415 nm and 503 nm a strong absorption band at $460{\sim}480nm$ and a H2 center at 986nm. Infrared spectra showed an absorption peak at $1344cm^{-1}$ (C center), which is the characteristics related to single substitutional nitrogen.

• 천문학회지
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• 제18권2호
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• pp.100-110
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• 1985

The HI features associated with HII regions and radio sources in the galactic-plane are searched in the Maryland-Green Bank Galactic 21-cm Line Survey. Among the twenty-eight such objects, twenty-five show HI depression features, two no feature, and an emission feature with excess HI brightness temperature. Most of these feature are surrounded by strong HI emissions. The depth of the HI depression is proportional to the radio continuum brightness temperature. The angular dimensions of the HI feature and radio source are comparable. The small HI depressions shown at the positions of HII region located in the outer solar circle are considered to be HI self-absorption features of very cold HI gas.

• 천문학회보
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• 제41권1호
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• pp.38.1-38.1
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• 2016

Gamma ray burst, the most brightest explosion phenomena in the current universe is well suited for study of high redshift universe. We report the afterglow multi-wavelength observation and GTC spectroscopy follow up of GRB 140304A which was exploded at z=5.283. The spectrum was shown damped Lyman alpha features and a series of absorption lines S, Si, SiII*, Oi, CII, CII*, SiIV are clearly detected at common redshift. Clear optical flares are detected when X-ray flare happened and a possible gamma-ray excess also. At this conference, we report on implications for the GRB host and environments using its absorption features which place the results in context to other well studied high redshift GRBs and studies about the ejecta using its observed flaring activities.

• 천문학회보
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• 제44권1호
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• pp.41.3-41.3
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• 2019

Ices in interstellar environments are well traced mostly by their absorption features in the near- to mid-infrared spectrum. The infrared camera (IRC) aboard AKARI provides us the near-infrared spectroscopic data which cover $2.5-5.0{\mu}m$ with a spectral resolution of R ~ 120. Our AKARI spectroscopic survey of young stellar objects (YSOs), including low-luminosity protostars and background stars, revealed the absorption features of $H_2O$, $CO_2$, CO, and XCN ice components. We present near-infrared spectra of the observed targets and compare their ice abundances with those previously derived from various YSOs and the background stars behind dense molecular clouds and cores. In addition, we suggest possible science cases for SPHEREx, NASA's new near-infrared space observatory, based on the results from our AKARI IRC spectroscopic study.

• Journal of Astronomy and Space Sciences
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• 제17권2호
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• pp.125-132
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• 2000

Long-slit spectra, covering the wavelength range 4050~5150$\AA$, have been used to investigate the radial behavior of absorption line features (G4300, Fe4383, Ca4455, Fe4531, Fe4668, and H$\beta$) along the major and minor axes of the bulge of M104. The heliocentric recession velocity of M104 has been derived as 1260$\pm$190${kms}^{-1}$. The strength of a number of metal absorption lines is decreasing with increasing radius, and the minor axis shows much steeper radial line gradients than the major axis. Line index of H$\beta$ has an opposite trend to other metal lines, i.e., increasing outward. The results in this paper imply that the properties of absorption line index distribution in M104 bulge have in many aspects similar trends to those of elliptical galaxies.

• 천문학회보
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• 제19권
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• pp.6.1-6.1
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• 1994

• 한국진공학회지
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• 제5권1호
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• pp.33-38
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• 1996

The induced linewidth, frequency shift and absorption spectrum for a molecular dipole in the vicinity of a phase -conjugate mirror have been investgated within a classical phenomenological model, with particularreference to the technique of optical phase conjugation by a surface. While the shifts and the widths show similar characteristics as those obtained recently by Bochove who considered the problem within the context of four-wave mixing, the results obtained in the present model can be defined uniquely with the possibility of an infinite lifetime for the excited admolecule . Furthermore, the absorption lineshape obtained here some interesting features which depend on both the magnitude and the phase of the complex reflectivity of the mirror.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.222-227
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• 2003

Recent advances in room-temperature, visible and near-IR diode laser sources for telecommunication, optical data storage applications are enabling combustion diagnostics system based on diode laser absorption spectroscopy. In contrast to some traditional sampling-based gas-sensing instruments, tunable diode laser absorption spectroscopy system is advantageous because of their non-invasive nature, high sensitivity, fast response time and real-time measurement capability. So, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor system arc now appearing for a variety of applications. The objective of this research is to take advantage of distributed feed-back diode laser and measure the $CO_{2}$ concentration (by using direct absorption and wavelength modulation spectroscopy methods). In addition to survey spectra of $CO_{2}$ bands and spectroscopic parameters between 1565 and 1579 run were computed at temperatures between 296 and 1200 K (by using HITRAN 2000 database). It experimentally found out that the features of direct absorption and wavelength modulation spectroscopy methods.

• 한국지형학회지
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• 제21권4호
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• pp.121-131
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• 2014

이 연구에서는 카올리나이트의 분광반사 특성과 ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) 영상 자료를 이용하여 경상남도 하동지역 고령토 광산의 분포를 추출하였다. ASTER 영상의 광물별 파장 흡수 밴드특성을 이용하여 고령토 광상의 주 구성 광물인 카올리나이트의 분포 양상을 추출하기 위해서 밴드 비연산 모델을 적용하였다. 분광반사 특성 곡선에 따르면 카올리나이트는 Al-OH에 의해서 0.96과 $2.18{\mu}m$ 파장 인근에서 흡수특성이 나타나며, $1.24{\mu}m$와 $1.38{\sim}1.41{\mu}m$에서 OH의 영향을 받는다. 이러한 카올리나이트 분광특성을 ASTER 영상에 적용하여 현재 개발 중인 고령토 광산을 포함하여 채굴적 등의 분포를 판독하였다.

• 천문학회지
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• 제36권spc1호
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• pp.21-27
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• 2003

In the present study, we have investigated morphology and evolution of small-scale Ha dynamic features on the quiet sun by analyzing video magnetograms and high resolution Ha images simultaneously taken for 5 hours at Big Bear Solar Observatory on April 18, 1997. From comparisons between time sequential longitudinal magnetograms and H$\alpha$ images covering $150" {\times} 150"$, several small-scale H$\alpha$ dynamic features have been observed at a site of magnetic flux cancellation. A close relationship between such features and cancelling magnetic fluxes has been revealed temporarily and spatially. Our results support that material injection by chromospheric magnetic reconnect ion may be essential in supporting numerous small-scale H$\alpha$ dynamical absorption features, being in line with recent observational studies showing that material injection by chromospheric magnetic reconnect ion is essential for the formation of solar filaments.