• Title, Summary, Keyword: spectra

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A Study on the High Resolution Infrared Spectra of an Asymmetric Top Molecule $CF_2Cl_2$

  • Jung, Hyun-Chai
    • Bulletin of the Korean Chemical Society
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    • v.9 no.5
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    • pp.275-280
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    • 1988
  • The high resolution IR spectra of freon-12($CF_2Cl_2$) for the bands of 671cm$^{-1},\;922cm^{-1},\;1102cm^{-1},\;and\;1160cm^{-1}$ were taken and the rotational vibrational analysis has been carried out. The band types of $671cm^{-1}\;and\;1102cm^{-1}$ were confirmed to be A and those of $922cm^{-1}\;and\;1160cm^{-1}$ were confirmed to be B. The theoretically synthesized spectra were matched with the experimentally obtained spectra to get some informations of the molecular rotational behavior as well as the overall band shape of the spectra.

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CARS Spectra of HCI, N₂, and C₂H₂ in the Gas Phase

  • 백선종;김중희;박주연;이성열;김홍래
    • Bulletin of the Korean Chemical Society
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    • v.16 no.9
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    • pp.810-813
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    • 1995
  • Coherent anti-Stokes Raman scattering (CARS) spectra of HCl, N2, and the ν1 fundamental of C2H2 have been measured in the gas phase. The measured spectra show rotational structures which originate from the Q-branch transitions. The spectra have successfully been simulated with proper selection rules, line positions, and relative intensities from room temperature Boltzmann population distributions. The vibration-rotation interaction constant α of HCl in the ground electronic state has been measured from the rotationally resolved CARS spectra which is α=0.3076 cm-1. Possibilities of optical pumping and of measuring state specific energy distributions of molecules are discussed.

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Expert System Approach for Vapor-Phase Infrared Spectra of Aromatic Compounds

  • Pyo Dongjin;Hwang Hoon;Lee Junyeoun
    • Bulletin of the Korean Chemical Society
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    • v.13 no.2
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    • pp.148-155
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    • 1992
  • Computerized interpretation of vapor phase infrared spectra using a novel expert system approach for spectra/structure correlation for vapor phase spectra is introduced. Rapid identification of aromatic functional groups of components in gaseous mixture can be achieved using this expert system.

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Self-Modeling Curve Resolution Analysis of On-line Near Infrared Spectra Measured during the Melt-Extrusion Transesterification of Ethylene/Vinylacetate Copolymer

  • Sasic, Slobodan;Kita, Yasuo;Furukawa, Tsuyoshi;Watari, Masahiro;Siesler, Heinz W.;Ozaki, Yukihiro
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • pp.1284-1284
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    • 2001
  • The transesterification of molten ethylene/vinylacetate (EVA) copolymers by octanol as a reagent and sodium methoxide as a catalyst in an extruder has been monitored by on-line near infrared (NIR) spectroscopy. A total of 60 NIR spectra were acquired for 37 minutes with the last spectrum recorded 31 minutes after the addition of octanol and catalyst was stopped. The experimental spectra show strong baseline fluctuations which are corrected for by multiplicative scatter correction (MSC). The chemometric methods of orthogonal projection approach (OPA) and multivariate curve resolution (MCR) were used to resolve the spectra and to derive concentration profiles of the species. The detailed analysis reveals the absence of completely pure variables that leads to small errors in the calculation of pure spectra. The initial estimation of a concentration that is necessary as an input parameter for MCR also presents a non-trivial task. We obtained results that were not ideal but applicable for practical concentration control. They enable a fast monitoring of the process in real-time and resolve the spectra of the EVA copolymer and the ethylene/vinyl alcohol (EVAL) copolymer to be very close to the reference spectra. The chemometric methods used and the decomposed spectra are discussed in detail.

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THE SPECTRAL DETERMINATIONS OF THE JOIN OF TWO FRIENDSHIP GRAPHS

  • Abdian, Ali Zeydi;Moez, Amirhossein Morovati
    • Honam Mathematical Journal
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    • v.41 no.1
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    • pp.67-87
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    • 2019
  • The main aim of this study is to characterize new classes of multicone graphs which are determined by their adjacency spectra, their Laplacian spectra, their complement with respect to signless Laplacian spectra and their complement with respect to their adjacency spectra. A multicone graph is defined to be the join of a clique and a regular graph. If n is a positive integer, a friendship graph $F_n$ consists of n edge-disjoint triangles that all of them meet in one vertex. It is proved that any connected graph cospectral to a multicone graph $F_n{\nabla}F_n=K_2{\nabla}nK_2{\nabla}nK_2$ is determined by its adjacency spectra as well as its Laplacian spectra. In addition, we show that if $n{\neq}2$, the complement of these graphs are determined by their adjacency spectra. At the end of the paper, it is proved that multicone graphs $F_n{\nabla}F_n=K_2{\nabla}nK_2{\nabla}nK_2$ are determined by their signless Laplacian spectra and also we prove that any graph cospectral to one of multicone graphs $F_n{\nabla}F_n$ is perfect.

Response Spectra of 2016 Gyeongju Earthquake and Comparison with Korean Standard Design Spectra (2016년 경주지진 스펙트럼과 한국표준설계스펙트럼의 비교)

  • Kim, Jae Kwan;Kim, Jung Han;Lee, Jin Ho;Heo, Tae Min
    • Journal of the Earthquake Engineering Society of Korea
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    • v.21 no.6
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    • pp.277-286
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    • 2017
  • On September 12, 2016, Gyeongju earthquake occurred. Its local magnitude was announced to be $M_L=5.8$ by Korea Meteorological Administration (KMA). Ground motion data recorded at KMA, EMC and KERC stations was obtained from their data bases. From the data, horizontal and vertical response spectra, and V/H ratio were calculated. The horizontal spectrum was defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. Applying the same procedure, the shape and transition periods of vertical spectrum was obtained. These results were compared with the Korean standard design spectra, which were developed from domestic and overseas intraplate earthquake records. The response spectra of Gyeongju earthquake were found to be almost identical with the newly proposed design spectra. Even the V/H ratios showed good agreement. These results confirmed that the method adopted when developing the standard design spectra were valid and the developed design spectra were reliable.

Studies on the Components of Fruits of Forsythia Koreana NAKAI (III). Occurrence of Ursolic Acid in the Fruits of Forsythia Koreana (Forsythia Koreana NAKAI 씨 (토연교)의 성분에 관한 연구 (III). Ursolic acid의 분리 및 확인)

  • Sae Hee Chang;Jae Soon Kim
    • Journal of the Korean Chemical Society
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    • v.17 no.6
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    • pp.444-449
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    • 1973
  • From the methanol extract of the fruits of Forsythia Koreana NAKAI a sapogenin and its derivatives were isolated. Through the mass spectra, ultraviolet spectra, nuclear magnetic resonance spectra, elemental analysis and chemical tests it was identified as ursolic acid.

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High Fidelity Color Capturing of CCD-Camera System by Using of Spectral Sensitivity Model (스펙트럼 특성 모델을 이용한 CCD카메라 시스템의 고성능 칼라 Capturing)

  • 이상진;신윤철;김일도;김문철
    • Proceedings of the IEEK Conference
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    • pp.1751-1754
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    • 2003
  • CCD Camera System으로 capture 한 image를 표준 display장치로 재현할 때 capture 할 당시의 원 피사체의 모습을 그대로 재현하여야만 한다. 그러나 일반 consumer 용 camera system의 CCD channel spectral sensitivity 특성이 인간의 spectral sensitivity(1(λ), m(λ), 5(λ)) 특성과 일치하지 않고, linear transform의 관계도 성립하지 않음으로써 capturing시 근본적인 color error가 발생하게 된다. 기존의 CCD Camera System 에서는 CCD sensor 의 color 정보와 display 장치의 color 정보와의 단순한 산술적인 관계로 color를 재구성하는 방법을 사용하고 있어 원 피사체의 color 를 그대로 재현할 수가 없다. 본 논문에서 제시하는 알고리즘은 CCD 의 channel spectral sensitivity특성 과 CIE-color matching function과의 관계를 고려하여 color를 재구성함으로써 color error를 줄이도록 하였다 제시된 알고리즘의 color error를 검증하기 위하여 물체의 고유반사율을 알고 있는 AGFA IT8.7-2 test chart(283 spectra), Dupont Paint Chips(120 spectra), Mcbeth Color Checker(64 spectra) 및 Natural Objects(170 spectra) 등 다양한 objects spectra(637 spectra) [1][2]를 이용하여 기존 방법의 알고리즘과 비교하여 보았다.

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Floor Response Spectra Analysis Including Correlations of Multiple Support Motions (층간의 상관관계를 고려한 다중 층응답스펙트럼 해석)

  • 윤정방;현창헌;공재식;윤재석
    • Computational Structural Engineering
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    • v.6 no.4
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    • pp.67-72
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    • 1993
  • This paper deals with the response spectra analysis method of the secondary structures including the correlation effect between the nonuniform multiple support excitations. Based on the random vibration theory, the multiple floor response spectra and the cross-correlation coefficient spectra of the floor motions are derived from the design ground response spectra. The example analysis results show that the proposed method yields more accurate results than those by the conventional multiple floor response spectra method without the correlation effects of the support motions. The present method may be easily employed in the seismic design of the secondary structures in engineering practice.

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Normalization and Search of the UV/VIS Spectra Measured from TLC/HPTLC (TLC/HPTLC에서 측정된 자외/가시부 스펙트럼의 표준화 및 검색)

  • Kang, Jong-Seong
    • YAKHAK HOEJI
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    • v.38 no.4
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    • pp.366-371
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    • 1994
  • To improve the identification power of TLC/HPTLC the in situ reflectance spectra obtained directly from plates with commercial scanner are used. The spectrum normalization should be carried out prior to comparing and searching the spectra from library for the identification of compounds. Because the reflectance does not obey the Lambert-Beer's law, there arise some problems in normalization. These problems could be solved to some extent by normalizing the spectra with regression methods. The spectra are manipulated with the regression function of a curve obtained from the correlation plot. When the parabola was used as the manipulating function, the spectra were identified with the accuracy of 97% and this result was better than that of conventionally used the point and area normalization method.

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