• Title/Summary/Keyword: Laboratory spectroscopy

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INTENSIVE OBSERVATION OF SAND AND DUST STORMS USING GROUND-BASED FOURIER TRANSFORM INFRARED SPECTROSCOPY IN ANMYEON, KOREA

  • Lee, Byung-Il;Kim, Yoon-Jae;Sohn, Eun-Ha;Kim, Mee-Ja;Lee, Kwang-Mog;Park, Joong-Hyun
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.142-145
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    • 2007
  • In order to analyze hyper-spectral properties of Sand and Dust Storm (SDS), dust observation experiment has been performed at the Korea Global Atmosphere Watch Center (KGAW) in Anmyeon form early March to middle of May, 2007. We measured down-welling radiances by using ground-based Fourier Transform Infrared Spectroscopy (FT-IR) at the time of overpass of AIRS. And radiative transfer model simulation has been carried out to estimate the effects of size distribution, components, and altitude of SDS over the high resolution infrared spectrum in the range of 500-1500 $cm^{-1}$ with a line-by-line radiative transfer model and compared them with FT-IR and AIRS/Aqua observing data.

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VISIBLE/NEAR-IR REFLECTANCE SPECTROSCOPY FOR THE CLASSIFICATION OF POULTRY CARCASSES

  • Chen, Yud-Ren
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.403-412
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    • 1993
  • This paper presents the progress of the development of a nondestructive technique for the classification of normal, septicemic , and cadaver poultry carcasses by the Instrumentation and Sensing Laboratory at Beltsville, Maryland, U.S.A. The Sensing technique is based on the diffuse reflectance spectroscopy of poultry carcasses.

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Impedance Spectroscopy of ${\pi}$-Conjugated Organic Materials

  • Kim, Seong-Hyun;Chu, Hye-Yong;Zyung, Taeh-Young;Yang, Yong-Suk
    • ETRI Journal
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    • v.26 no.2
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    • pp.161-166
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    • 2004
  • AC electrical properties of organic light-emitting diodes with poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV), poly[2,5-bia(dimethyloctylsilyl)-1,4-phenylenevinylene] (BDMOS-PPV), and tris-(8-hydroxyquinolate)-aluminum $(AlQ_3)$ as light-emitting materials are studied. The frequency-dependent real and imaginary parts of impedance were fitted using an equivalent circuit. We found that the conduction mechanism is a space-charge limited current with exponential trap distribution.

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Phase Imaging of Worn Surface of TiN Coating and Interpretation by Force Spectroscopy

  • Hyo Sok;Chizhik, S-A;I Luzinov
    • KSTLE International Journal
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    • v.1 no.2
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    • pp.69-75
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    • 2000
  • The paper compares topography, phase contrast and force spectroscopy in atomic force microscopy data for evaluating the microheterogeneity of surface layer. The worn surface of ion-plated TiN coating was measured using both a laboratory-built and a commercial AFM. The results of analysis revealed structural and micromechanical heterogeneity of the worn surfaces. We demonstrated that the phase image allows relatively qualitative estimation of elastic modulus of the sample surface. The tribolayer formed in the worn surface possessed much lower stiffness than the original coating. It is shown that the most stable phase imaging is provided with a stiff cantilever. In this case, phase contrast is well conditioned, first of all, by microheterogeneity of elastic properties of the investigated surfaces. In this study an attempt was also made to correlate the results of phase imaging with that of the farce spectroscopy. The joint analysis of information on the surface properties obtained by the phase imaging and quantitative data measured with the force spectroscopy methods allows a better understanding of the nature of the surface micromechanical heterogeneity.

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Phase identification of $C_3N_4$ in CN films prepared by rf plasma chemical vapor deposition and dc magnetron sputtering

  • Fu, Dejun;Wu, Dawei;Zhang, Zhihong;Meng, Xianquan;He, Mengbing;Guo, Huaixi;Peng, Yougui;Fan, Xiangjun
    • Journal of the Korean Vacuum Society
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    • v.7 no.s1
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    • pp.140-148
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    • 1998
  • We prepared $C_3N_4$ films by rf plasma enhanced chemical vapor deposition(PCVD) and alternating $C_3N_4$/TiN composite films by dc magnetron sputtering. X-ray diffraction (XRD) and transmission electron diffraction (TED) revealed that the structure of the films is amorphous or polycrystalline, depending on deposition conditions and heat treatment. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of $sp_3\; and sp _2$ hybridized C atoms bonded with N atoms in the tetrahedral and hexagonal configurations, respectively. Graphite-free $C_3N_4$ films were obtained by PCVD under optimal conditions. To prepare well crystallized $C_3N_4$ films by magnetron sputtering, we introduced negatively biased gratings in the sputtering system. CN films deposited at grating voltages (Vg) lower than 400V are amorphous. Crystallites of cubic and $\beta$-$C_3N_4$ were formed at increased voltages.

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Preparation of Highly Visible-Light Photocatalytic Active N-Doped TiO2 Microcuboids

  • Zhao, Kang;Wu, Zhiming;Tang, Rong;Jiang, Yadong
    • Journal of the Korean Chemical Society
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    • v.57 no.4
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    • pp.489-492
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    • 2013
  • N-doped $TiO_2$ microcuboids were successfully prepared by a simple one-pot hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. It was found that the N-doped $TiO_2$ microcuboids enhanced absorption in the visible light region, and exhibited higher activity for photocatalytic degradation of model dyes. Based on the experimental results, a visible light induced photocatalytic mechanism was proposed for N-doped anatase $TiO_2$ microcuboids.

Measurement of the excited Xe atoms density of matastable state$(1S_5)$ under various binary gas mixtures(Ne-Xe) by Laser Absorption Spectroscopy.

  • Lee, Jun-Ho;OH, P.Y.;Moon, M.W.;Ko, B.D.;Jeong, J.M.;Lee, H.J.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1218-1220
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    • 2005
  • We have developed laser absorption spectroscopy system for the measurement of excited Xe atoms in micro-discharged AC-PDP plasma. In this study, we have measured the absorption signals for the $1S_5$ xenon metastable state in the PDP cell with the various gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) under fixed gas pressure of 350 Torr and the eletrode gap distance of 50um. It is found that the maximum excited xenon densities are $1.2^{\ast}10^{12}\;cm^{-3}$, $1.8^{\ast}10^{12}\;cm^{-3}$ and $2.7^{\ast}10^{12}cm^{-3}$ for gas mixtures of Ne-Xe(1%), Ne-Xe(4%) and Ne-Xe(10%) respectively, in this experiment.

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Relationship between Exciton Lifetime and Energy Transfer in Light Emitting Polymers

  • Yu, Jae-Woong;Kim, Jai-Kyeong;Cho, Hyun-Nam;Kim, Dong-Young;Song, Nam-Woong;Kim, Dong-Ho;Kim, Chung-Yup
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.209-210
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    • 2000
  • The energy transfer from photoexcited polyvinylcarbazole (PVK) chromophores with a bandgap of 3.7 eV as a donor to fluorophores of poly(dihexylfluorenevinylene) (PDHFV) or poly(dihexylfluorenedihexoxyphenylenevinylene) (PDHFHPV) as an acceptor in bilayered specimens should be carried out since the spectral overlap pairs fulfills the requirement for the $F{\"{o}}rster-type$ condition. However, the energy transfer rate from the chromophores with a wider bandgap to the fluorophores with a narrower bandgap is proved to be strongly dependent on the lifetime ratio between the excitons.

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