• Title, Summary, Keyword: Spectroscopy

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Monitoring Oxidation Behavior of [C70]Fullerene by Ultrasonic Spectroscopy ([C70]풀러렌 산화 반응의 거동에 관한 초음파 분광학적 고찰)

  • Ko, Weon Bae
    • Elastomers and Composites
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    • v.49 no.2
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    • pp.155-159
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    • 2014
  • High resolution ultrasonic spectroscopy was used to observe the oxidation of [$C_{70}$]fullerene with 3-chloroperoxy benzoic acid in 1,2-dichlorobenzene. UV-vis spectroscopy and X-ray diffraction confirmed the resulting roducts of [$C_{70}$]fullerene oxidation.

The Chemical Constituents from Unidentified Sponge (해면의 화학적 성분 연구)

  • Park, Seon Gu;Paul J. Scheuer
    • Journal of the Korean Chemical Society
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    • v.38 no.2
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    • pp.169-173
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    • 1994
  • The previously reported cytotoxic metabolites, against the KB cell line, xestoquinone, halenaquinol sulfate and $halenaquinol^{5,6}$ were isolated from the unidentified sponge collected in October 1992, Manado Bay, Sulawesi in Indonesia. Their structure were elucidated by $^1H-,\;^{13}C$-NMR, $^1H-,\;^{13}C$(1 bond) Heteronuclear Multiple Quantum Coherence Spectroscopy$(HMQC)^1$, $^1H-,\;^{13}C$C(2 and 3 bond) Heteronuclear multiple Bond Correlation Spectroscopy$(HMBC)^2$, Electron Impact Mass Spectroscopy(EI ms), Ultraviolet Spectroscopy(UV), and Infrared Spectroscopy(IR)

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Consideration of Temperature and Slip Correction for Photothermal Spectrometry

  • Lee, Jeonghoon
    • Asian Journal of Atmospheric Environment
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    • v.9 no.1
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    • pp.86-90
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    • 2015
  • Temperature was considered to estimate the minimum detectable absorption coefficient of aerosol particles from photothermal spectroscopy. Light energy absorbed by subsequent emission from the aerosol results in the heating of the aerosol sample and consequently causes a temperature change as well as changes in thermodynamic parameters of the sample. This thermal effect is the basis of photothermal spectroscopy. Photothermal spectroscopy has several types of techniques depending on how the photothermal effects are detected. Photothermal interferometry traces the photothermal effect, refractive index, using an interferometer. Photoacoustic spectroscopy detects the photothermal effect, sound wave, using a microphone. In this study, it is suggested that the detection limit for photothermal spectroscopy can be influenced by the introduction of a slip correction factor when the light absorption is determined in a high temperature environment. The minimum detectable absorption coefficient depends on the density, the specific heat and the temperature, which are thermodynamic properties. Without considering the slip correction, when the temperature of the environment is 400 K, the minimum detectable absorption coefficient for photothermal interferometry increases approximately 0.3% compared to the case of 300 K. The minimum detectable absorption coefficient for photoacoustic spectroscopy decreases only 0.2% compared to the case of 300 K. Photothermal interferometry differs only 0.5% point from photoacoustic spectroscopy. Thus, it is believed that photothermal interferometry is reliably comparable to photoacoustic spectroscopy under 400 K.

Three-Dimensional Fluid Flow Analysis of Photoacoustic Spectroscopy Cell for Measurement of Automotive Exhaust Gas (자동차 배출가스 측정을 위한 Photoacoustic Spectroscopy Cell의 3차원 유동장 해석)

  • 김현철;박종호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.2
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    • pp.111-118
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    • 2003
  • Recently, environmental damage to urban area becomes serious problem due to the exhaust emissions by increasing the number of vehicle. Especially, exhaust emission from diesel vehicles are blown to be harmful to human health and environment. Photoacoustic Spectroscopy system is very useful technology for simultaneous and continuous measurement of the various components of the automotive exhaust gas. In this study, in order to reduce emission gases from automobile, we tried to develop the measurement system of Photoacoustic Spectroscopy. To improve performance of high sensitive Photoacoustic Spectroscopy system for automotive exhaust emissions, the shape of Photoacoustic Spectroscopy cell was optimized to use the flow analysis. And Exhaust emission data of the 1,500cc gasoline engine was fixed the working fluid. The characteristics of fluid flow for cell were analyzed by various conditions in detail.

The Chemical Constituents from the Sponge Spongia sp. (해면 Spongia sp.의 화학적 성분 연구)

  • Park, Sun-Ku;Oh, Chang-Sok;Scheuer, Paul-J.
    • Journal of the Korean Chemical Society
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    • v.39 no.4
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    • pp.301-305
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    • 1995
  • The cytotoxic metabolites, against the KB cell line, halenaquinone, epispongiatriol and aldisin were isolated from the sponge Spongia sp. collected in September 1992, Manado Bay, Sulawesi in Indonesia. Their structures were elucidated by 1H, 13C NMR, 1H 13C(1 bond) Heteronuclear Multiple Quantum Coherence Spectroscopy (HMQC), 1H 13C(2 and 3 bond) Heteronuclear Multiple Bond Correlation Spectroscopy (HMBC), Electron Impact Mass Spectroscopy (EI ms) and Infrared Spectroscopy (IR).

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LONG-SLIT SPECTROSCOPY FOR EXTENDED OBJECTS (면천체(EXTENDED OBJECTS)에 대한 긴 슬릿 분광관측 연구)

  • SUNG EON-CHANG
    • Publications of The Korean Astronomical Society
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    • v.15 no.spc1
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    • pp.39-60
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    • 2000
  • We will discuss two-dimmensional spectrophotometry including long-slit spectroscopy and narrow-band imaging. The basic principles, applications, and techniques of observations and data reduction of spectroscopy and spectrophotometry for extended objects are described. This discussion will focus on practical long-slit spectroscopy using a Cassegrain spectrograph attached with 2 or 4m class telescopes and on imaging spectrophotometry using narrow-band interference filter sets. We will discuss scientific applications.

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Coherent Control of Autler-Townes Splitting in Photoelectron Spectroscopy: The Effect of Laser Intensity and Laser Envelope

  • Qin, Chaochao;Zhai, Hongsheng;Zhang, Xianzhou;Liu, Yufang
    • Bulletin of the Korean Chemical Society
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    • v.35 no.11
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    • pp.3294-3298
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    • 2014
  • We theoretically investigated the coherent control of Autler-Townes splitting in photoelectron spectroscopy of K2 molecule within an ultrafast laser pulse by solving the time-dependent Schrodinger equation using a quantum wave packet method. It was theoretically shown that we can manipulate the splitting of photoelectron spectroscopy by altering the laser intensity. Furthermore, it was found that the percentages of each peak in photoelectron spectroscopy can be controlled by changing the envelope of the laser pulse.

Coherent Two-Dimensional Optical Spectroscopy

  • Cho, Min-Haeng
    • Bulletin of the Korean Chemical Society
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    • v.27 no.12
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    • pp.1940-1960
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    • 2006
  • Theoretical descriptions of two-dimensional (2D) vibrational and electronic spectroscopy are presented. By using a coupled multi-chromophore model, some examples of 2D spectroscopic studies of peptide solution structure determination and excitation transfer process in electronically coupled multi-chromophore system are discussed. A few remarks on perspectives of this research area are given.