• Bulletin of the Korean Chemical Society
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• 제15권2호
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• pp.145-150
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• 1994

The low temperature luminescence and excitation, room-temperature UV-visible and infrared spectra of [Cr(${\pm})chxn_3]Cl_3$ (chxn=trans-1,2-cyclohexanediamine) have been measured. It is found that the zero-phonon line in the excitation spectrum splits into two components by $47\;cm^{-1}$. The eight electronic transitions due to spin-allowed and spin-forbidden are assigned. As expected, nitrogen atoms of chxn ligand have strong ${\sigma}-donor $properties toward chromium(Ⅲ). The positions and splittings of sharp-line transitions are analyzed as a function of the Cartesian bite (${\alpha}$) and twist (${\beta}$) angles to predict the metal-ligand geometry.

• 천문학회지
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• 제40권1호
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• pp.1-7
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• 2007

About 10 percent of quasars are known to exhibit deep broad absorption troughs blueward of prominent permitted emission lines, which are usually attributed to the existence of outflows slightly above he accretion disk around the supermassive black hole. Typical widths up to 0.2c of these absorption roughs indicate the velocity scales in which special relativistic effects may not be negligible. Under he assumption of the ubiquity of the broad absorption line region in quasars, the broad emission line flux will exhibit Thomson scattered components from these fast outflows. In this paper, we provide our Monte Carlo calculation of linear polarization of singly Thomson scattered line radiation with the careful considerations of special relativistic effects. The scattering region is approximated by a collection of rings that are moving outward with speeds ${\upsilon}=c{\beta}<0.2c$ near the equatorial plane, and the scattered line photons are collected according to its direction and wavelength in the observer's rest frame. We find that the significantly extended red tail appears in the scattered radiation. We also find that the linear degree of polarization of singly Thomson scattered line radiation is wavelength-dependent and hat there are significant differences in the linear degree of polarization from that computed from classical physics in the far red tail. We propose that the semi-forbidden broad emission line C III]1909 may be significantly contributed from Thomson scattering because this line has small resonance scattering optical depth in the broad absorption line region, which leads to distinct and significant polarized flux in this broad emission line.

• Journal of Photoscience
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• 제11권1호
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• pp.19-23
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• 2004

The sharp-line absorption spectrum of microcrystalline samples of cis-[Cr(cycb)$Cl_2$]Cl (cycb=rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been measured between 13000 and $16000 cm^{-1}$ at temperatures down to 5K. The 77K emission and excitation spectra, and 298 K infrared and visible absorption spectra have also been measured. The nine electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using the observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex. The zero-phonon line in the sharp-line absorption spectrum splits into two components by $240 cm^{-1}$ , and the $large ^2$$_E{g}$ splitting can be reproduced by the modem ligand field theory. It is confirmed that nitrogen atoms of the macrocyclic cycb ligand have a strong $\sigma$-donor character, but chloride ligand has weak $\sigma$- nd $\pi$-donor properties toward chromium(III) ion.n.

• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.903-908
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• 2005

The sharp-line absorption and emission spectra of $(H_{13}O_6)${$trans-[Cr(Me_2tn)_2Br_2]$}$_2Br_2(ClO_4)\;(Me_2$tn = 2,2-dimethyl-1,3-diaminopropane) have been measured between 13000 $cm^{-1}$ and 16000 $cm^{-1}$ at 5 K. The 298 K infrared and visible absorption spectra have also been measured. The nine electronic bands due to spin-allowed and spin-forbidden transitions were assigned. Using observed transitions, a ligand field analysis has been performed to probe the ligand field properties of coordinated atoms in the title chromium(III) complex ion. The zero-phonon line in the sharp-line absorption spectrum splits into two components by 286 $cm^{-1}$, and the large $^2E_g$ splitting can be reproduced by the modern ligand field theory. It is confirmed that nitrogen atoms of the Me2tn ligand have a strong $\sigma$-donor character, but the bromide has weak $\sigma$- and $\pi$-donor properties toward chromium(III) ion.

• 천문학회보
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• 제44권2호
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• pp.48.1-48.1
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• 2019

We found a diffuse Hα feature with a large size of ~2' around a Herbig star, MWC 1080. It shows a strong correlation with the elongated outflow cavity centered on the star. To investigate the diffuse Hα source and the molecular cavity in detail, we carried out the high-resolution NIR spectroscopy using IGRINS. We detected six hydrogen Brackett line series, seven H2 lines, and an [Fe II] forbidden line. With the obtained spatial, kinematic, and line ratio results, we discuss the characteristics of the central MWC 1080A, the NE outflow cavity, and the SE molecular cloud regions separately. Most of the bright Brγ sources around MWC 1080A were found to be reflection nebulae, but a point-like Brγ source close to another young star, MWC 1080E, was identified as a distinct source due to MWC 1080E itself. The narrow components of the H2 lines observed around MWC 1080A were found to trace PDRs located on the wall of the main outflow cavity. Based on the shock-excited H2 and [Fe II] lines detected just inside a bow-shock shape Hα feature, we suggest that it represents the actual shock at the head of the NE outflow from MWC 1080A. Also, we newly detected the shock-excited H2 and [Fe II] lines with highly blueshifted velocities in the SE molecular cloud region. They could be related to unrevealed outflows from other young stars existing around MWC 1080A.

• 한국지구과학회지
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• 제29권5호
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• pp.419-427
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• 2008

The Galactic planetary nebulae emit many strong recombination and forbidden lines. By analyzing such lines, the physical condition of the planetary nebulae has been inferred using the strategically important diagnostic line ratios. In order to fully understand the physical condition of a planetary nebula and to derive its chemical abundances, the photoionization model codes, e.g., CLOUDY and NEBULA, were employed for an analysis of gaseous nebular spectra. For the well-studied, relatively simple planetary nebula NGC 7026, theoretical investigation was done with about the same input parameters in models. The predictions made by both codes seem to be in good accord. However, the predicted physical conditions, such as electron temperature and density, are slightly different. Especially, the electron temperatures are predicted to be higher in CLOUDY, which may cause a problem in chemical abundance determination. Our analysis shows that the main discordance may occur due to the diffuse radiation.

• Journal of Photoscience
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• 제7권3호
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• pp.97-101
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• 2000

The 77 K emission and excitation spectra, and 298 K infrared and absorption spectra of mer-[CrCl(en)(dpt)]ZnCl$_4$(en=1,2-diaminoethane; dpt=1,5,9-triazanonane) have been measured. Ligand field electronic transitions due to spin-allowed and spin-forbidden are assigned. The zero-phonon line in the excitation spectrum splits into two components by 151$cm^{-1}$ /, and large$^2$E$^{g}$ splitting can be reproduced by the modern ligand field theory. It is confirmed that nitrogen atoms of the en and dpt ligands have a strong $\delta$-donor character, but chloride ligand has weak $\delta$-and $\pi$-donor properties toward chromium(III) ion.

• 천문학회보
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• 제39권2호
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• pp.75.1-75.1
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• 2014

We present the result of a long-slit spectroscopic study of DG Tau, which is known to emanate parsec-scale outflows. To study the kinematics and physical properties of the jet, we obtained the optical emission lines of $H{\alpha}$, [OI], [NII], and [SII] from HH 158 and HH 702 using the long-slit spectrograph at Bohyunsan Optical Astronomical Observatory. HH 158 shows the peak radial velocity in a range of ~ - 270 to - 30 km s-1. HH 702, located at 11' away from DG Tau shows the velocity of ~ - 80 km s-1. The proper motion velocities of detected knots are estimated through the comparisons with the locations of those knots in the previous studies. We also examine the variations of physical parameters depending on the velocity distribution and the distance from the source using line ratio maps derived from obtained forbidden emission lines.

• Journal of Photoscience
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• 제7권1호
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• pp.21-26
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• 2000

The photoemission and excitation spectra of cis-[Cr(cyclam)F$_2$]ClO$_4$ (cyclam = 1,4,8,11-tetraazacy-clotetradecane) taken at 77 K are reported. The 298 K mid- and far-infrared spectra are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. The zero-phonon line In the excitation spectrum splits into two components by 169 cm$^{1}$, and the large $^2$E$_{g}$ splitting can be reproduced by the ligand field theory. According to the ligand field analysis, we can confirm that nitrogen atoms of the cyclam ligand have a strong c-donor character, and fluoride ligand also has strong $\sigma$- and $\pi$-donor properties toward chromium(III) ion.n.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.59-63
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• 2003

Modal properties of guided waves along circular dispersive double negative (DNG) index metamaterial rod waveguides are numerically investigated. Identical forms of dispersive dielectric and magnetic material constants are used for simplicity. For degenerated azimuthally symmetric mode, a multimode region, a single mode region, a band gap region and a forbidden region are found which cannot be observed in the case of the conventional dielectric rod waveguide. As the normalized frequency goes down, discrete guided modes are continuously generated, which is a reverse property of conventional dielectric rod waveguide. Also, there are high-frequency cutoffs, which have been generally examined in dispersive circular geometries such as a plasma column or a plasma Goubau line. In the single mode region, both the low- and high-frequency cutoffs are existed where the propagation constants are continued between the guided oscillating and surface modes.