• Title/Summary/Keyword: Spectroscopic studies

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SPECTROSCOPIC STUDIES OF STARBURST GALAXIES ; THE DYNAMICAL STRUCTURE OF BLUE COMPACT DWARF CALAXY HARO 6

  • Chun, Mun-Suk;Moon, Hong-Kyu;Sung, Eon-Chang
    • Journal of Astronomy and Space Sciences
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    • v.12 no.1
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    • pp.1-13
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    • 1995
  • We carried out photometric and spectroscopic observatious of the blue compact dwarf galaxy Haro 6 in the Virgo Cluster of Galaxies. The long-slit spectroscopy was employed at three position angles, $\Phi$=$0^{\circ}$, $\Phi$=$30^{\circ}$, and $\Phi$=$120^{\circ}$with CCD camera mounted on the Cassegrain Spectrograph. Based on the mean intrinsic axial ratio < $q_0$ >=0.3, we derived inclination I of the system as $44^{\circ}$using our composite V-band CCD image. Careful analysis on the velocity field of the system shows an asymptotically fiat rotation curve with the maximum rotational velocity $V(r)_{max}$ reaches about 12km/sec. The calculation of the dynamical mass of Haro 6 with a simple mass model is briefly discussed with emphasis on the mass to luminosity ratio. From the IRAS Point Source Cataloque, we derived dust-to-gas ratio which indicates relatively low dust content, thus tempting us to conjecture the youth of the system.

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Real-time Spectroscopic Ellipsometry studies of the Effect of Preparation Parameters on the Coalescence Characteristics of Microwave-PECVD Diamond Films

  • Hong, Byungyou
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1998.06a
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    • pp.49-54
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    • 1998
  • The growth of diamond films in plasma enhanced chemical vapor deposition(PECVD) processes requires high substrate temperatures and gas pressures, as well as high-power excitation of the gas source. Thus determining the substrate temperature in this severe environment is a challenge. The issue is a critical one since substrate temperature is a key parameter for understanding and optimizing diamond film growth. The precise Si substrate temperature calibration based on rapid-scanning spectroscopic ellipsometry have been developed and utilized. Using the true temperature of the top 200 ${\AA}$ of the Si substrate under diamond growth conditions, real time spectroellipsometry (RTSE) has been performed during the nucleation and growth of nanocrystallind thin films prepared by PECVD. RTSE shows that a significant volume fraction of nondiamond(or{{{{ {sp }^{2 } -bonded}}}}) carbon forms during thin film coalescence and is trapped near the substrate interface between ∼300 ${\AA}$ diamond nuclei.

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SPECTROSCOPY OF PLANETS AND COMETS (거대 행성들과 혜성들의 분광학)

  • KIM SANG JOON;LEE YOUNG SIEK;YI YU;KIM YOUNG HA
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc1
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    • pp.31-38
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    • 2000
  • We have presented detected molecules, atoms, radicals, ions, and dimers in the atmospheres of planets and comets from Earth-based and spaceborne observatories during the last 3 decades. We have reviewed spectroscopic studies on the auroral emissions and air glows of the giant planets, and briefly summarized spectroscopic observations of dimers in the atmospheres of the giant planets and Titan. In particular, we highlighted the recent detections of new molecular emissions and absorptions in the spectra of the giant planets, Titan, and recent bright comets from spaceborne or ground-based observatories. We also reviewed current models and theories of the origin and evolution of the solar system, and implications of isotopic ratios in these atmospheres.

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SPECTROSCOPIC STUDIES IN X-RAY ASTRONOMY (X-선 천문 분야의 분광관측 연구)

  • CHOI CHUL-SUNG
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc1
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    • pp.73-83
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    • 2000
  • X-ray astronomy deals with measurements of the electromagnetic radiation in the energy range of $E\~0.1-100 keV (\lambda\~0.12-120{\AA})$. The wavelength of X-ray is comparable to the size of atoms, so that the photons in the X-ray range are usually produced and absorbed by the atomic processes. Since the launch of the first X-ray astronomy satellite 'Uhuru' in 1970, technological advances in a launch capability and a detection capability make X-ray astronomy one of the most rapidly evolving fields of astronomical research. Particularly, a spectral resolving power $E/{\Delta}E$ has been increased by an order of 2 - 3 (in the energy range of 0.1 - 10 keV) during the past 30years. In this paper, I briefly review a developing process of the resolving power and spectroscopic techniques. Then I describe important emission/absorption lines in X-ray astronomy, as well as diagnostics of gas property with line parameters.

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Spectroscopic characterization of electroluminescent ZnS:Cu,Cl phosphor coated by sol-gel process

  • Lee, You-Hui;Han, Chi-Hwan;Han, Sang-Do;Chang, Mi-Youn;Sharma, Gaytri.;Park, Youn-Bong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1323-1326
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    • 2005
  • The photoluminescence, electroluminescence and surface properties of ZnS:Cu,Cl phosphor coated by sol-gel process were studies. Na-silicate was used as precursor coating material. pH of solution and the concentration of Na-silicate are the important conditions to obtain the uniform coating on the phosphors. Also, the electroluminescent devices were made with Na-silicate coated phosphor. The spectroscopic characterization is performed by photospectrometer.

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ULTRAVIOLET AND VISIBLE SPECTROSCOPIC DATABASE FOR ATOMS AND MOLECULES IN CELESTIAL OBJETS

  • Kim, Sang-J.
    • Publications of The Korean Astronomical Society
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    • v.9 no.1
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    • pp.111-166
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    • 1994
  • I have developed a UV and visible spectroscopic database (UVSD) for atoms and molecules, which are found in interstellar medium, stars, galaxies, and in the atmospheres of the earth, planets, satellites, and comets. This UV and visible database, which is machine-readable, consists of three different sub-databases depending upon the characteristics of the sub-databases: (A) atomic and molecular line listings from laboratory observations or theoretical studies; (B) absorption spectra measured in laboratories; and (C) solar UV, visible, and infrared spectral atlases. The UVSD is in a very initial stage of development compared with other well organized and established infrared and microwave databases. In order to make a good quality and complete database, substantial efforts should be made for the acquisition of scattered important data from laboratories or institutions, and then the acquired heterogeneous data should be peer-reviewed and standardized.

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Investigation on the Interaction of Gabapentin with Bovine Serum Albumin by Spectroscopic Techniques

  • Ashoka, S.;Seetharamappa, J.;Kandagal, P.B.;Shaikh, S.M.T.
    • Journal of Photoscience
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    • v.12 no.3
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    • pp.113-117
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    • 2005
  • Spectroscopic investigations on the interaction of gabapentin (GBP) with bovine serum albumin (BSA) were reported. The association constant of GBP-BSA system was determined at different temperatures (298, 302, 306 and 311 K) based on the fluorescence quenching results. The GBP was found to quench the fluorescence of BSA through static mechanism. Thermodynamic parameters, the standard enthalpy change, $({\Delta}H^o)$ and the standard entropy change $({\Delta}S^o)$ were observed to be $-9.61{\pm}0.008\;kJ\;mol^{-1}$ and $3.58{\pm}0.011\;Jmol^{-1}K{-1}$ respectively. These indicated that the hydrophobic and electrostatic forces played a role in the interaction of GBP with BSA. The negative value of ${\Delta}G^o$ revealed that the binding reaction is spontaneous. The circular dichroism studies indicated the conformational changes in BSA upon interaction with GBP. The effect of some metal ions on the binding constant was also investigated.

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Radial gradients of line indices within the Galactic globular clusters

  • Jo, Jae-Il;Yun, Seok-Jin
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.84.2-84.2
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    • 2010
  • Radial changes of stellar population within the Galactic globular clusters have been reported in many spectroscopic and photometric studies. We present new integrated spectroscopic data for 24 Galactic globular clusters and have measured line indices within various aperture sizes. Radial gradients have been investigated for the Balmer lines and metal lines (Mgb). Our results show an increase in the strength of the Balmer lines toward the centres in some clusters including NGC7078, NGC7089, and NGC6934, in which colour gradients also have been detected previously. However, some other clusters show little trend or even an increase toward the outskirt in the Balmer lines. Metal sensitive lines generally have an anti-correlation with the Balmer lines. We discuss possible stellar populations being responsible for the radial change in line indices.

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Spectroscopic Studies of TP6F PI Switched by Hole-Injection

  • Lee, Gyeong-Jae;Im, Gyu-Uk;Kim, Dong-Min;Lee, Mun-Ho;Gang, Tae-Hui;Jeong, Seok-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.297-298
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    • 2011
  • Metal/poly (4,4'-aminotriphen-ylene hexafluoroisopropylidenediphthalimide) (TP6F PI)/metal structure exhibited an electrically volatile phase transition with high (OFF) or low (ON) resistive states when voltage between electrodes swept. Here, we demonstrate a noble set-up in which holes are injected by photoelectron emission process during the voltage sweep instead of direct charge carrier injection via metal electrode, which enables direct investigation into changed electronic structures of TP6F PI both in ON and OFF states using photoemission spectroscopy methods. In the I-V measurement, TP6F PI shows a non-volatile behavior. In spectroscopic results, this non-volatile behavior is leaded from the structural modification of the O=C double bond in phthalimide of TP6F PI by hole injection.

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Surface-Enhanced Raman Spectroscopic Studies of Oriented Monolayers on Electrode Surfaces

  • Yoon, Wan-Shik;Im, Jung-Hyuk;Kim, Jae-Ho
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.699-705
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    • 1995
  • Monolayers of hypericin, a photodynamic polycyclic quinoidal compound, were prepared at the air-water interface, and were transferred to metal substrates to form Langmuir-Blodgett (LB) monolayers. The structural characteristics of hypericin LB monolayers and self-assembled (SA) monolayers were investigated using surface-enhanced resonance Raman scattering (SERRS) spectroscopy. Both the spectroscopic data and the surface pressure - area (${\pi}-A$) isotherms suggest that hypericin forms ${\pi}-{\pi}$ aggregates that orient vertically to the subphase surface. Whereas the ordering and orientation of control was less effective in SA monolayers, a higher structural regularity was attained in LB systems. The effect of subphase on the structural integrity of the monolayer was also investigated.

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