• Title, Summary, Keyword: spectra

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Application of Fourier Transform Infrared Speactorcopy to Qualitative and Quantitative Analysis of Fiber Blends(I) - Qualitative Analysis of Cotton Fiber Blends by FTIR- (Fourier Transform IR에 의한 혼방섬유의 정성 및 정량분석(I) -면 혼방품의 정성분석에의 FTIR 적용-)

  • 김갑진;윤병숙
    • Textile Science and Engineering
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    • v.23 no.3
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    • pp.1-1
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    • 1986
  • The IR spectra of cotton, PET, nylon 6, viscose rayon, polyproplene, acrylic and acetate rayon were obtained by using a FTIR spectrometric method. All these spectra were weight-normalized to a sample weight of 2 mg. The theoretical weight-normalized spectra of cotton/other fiber [A] at various blend ratios were obtained by the method as follows: the normalized cotton spectrum was multiplied with the scale factor, FC which was the corresponding value to the blend ratio of cotton. The same method as above was applied to the fiber(A) using the scale factor FA. Then the two spectra were added to produce the theoretical spectrum of the cotton/A fiber with that blend ratio. The peak-characterization data of these the theoretical IR spectra of cotton blends at various blend ratios could be well offered for qualitative analysis of cotton blends.

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Prediction Equation of Spectral Acceleration Responses in Low-to-Moderate Seismic Regions using Domestic and Overseas Earthquake Records (국내·외 계기지진 정보를 활용한 중·약진 지역의 스펙트럴 가속도 응답 예측식)

  • Shin, Dong Hyeon;Kim, Hyung Joon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.2
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    • pp.77-86
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    • 2018
  • This study develops an empirical prediction equation of spectral acceleration responses of earthquakes which can induce structural damages. Ground motion records representing hazards of low-to-moderate seismic regions were selected and organized with several influential factors affecting the response spectra. The empirical equation and estimator coefficients for acceleration response spectra were then proposed using a robust nonlinear optimization coupled with a regression analysis. For analytical verification of the prediction equation, response spectra used for low-to-moderate seismic regions were estimated and the predicted results were comparatively evaluated with measured response spectra. As a result, the predicted shapes of response spectra can simulate the graphical shapes of measured data with high accuracy and most of predicted results are distributed inside range of correlation of variation (COV) of 30% from perfectly correlated lines.

Simulations of Two-Dimensional Electronic Correlation Spectra

  • Kim, Hak Jin;Jeon, Seong Jun
    • Bulletin of the Korean Chemical Society
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    • v.22 no.8
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    • pp.807-815
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    • 2001
  • Two-dimensional (2D) correlation method, which generates the synchronous and the asynchronous 2D spectrum by complex cross correlation of the Fourier transformed spectra, is an analysis method for the changes of the sample spectrum induced by vari ous perturbations. In the present work, the 2D electronic correlation spectra have been simulated for the cases where the sample spectrum composed of two gaussian bands changes linearly. When only the band amplitudes of the sample spectrum change, the synchronous spectrum shows strong peaks at the band centers of the sample spectrum, but the asynchronous spectrum does not make peaks. When the sample spectrum shifts without changing intensity and width, the synchronous spectrum shows peaks around the initial and final positions of the band maximum and the asynchronous spectrum shows long peaks spanning the shifting range. The band width change produces the complex 2D correlation spectra. When the sample spectrum shifts with band broadening, the width change by 50% of full width at half maximum (FWHM) does not give so large an effect on the correlation spectrum as the spectral shift by one half of FWHM of the sample spectrum.

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Qualitative Analysis by Derivative Spectrophotometry (II) - Computer-assisted spectral analysis using derivative spectra and Root Mean of Squares of differences -

  • Park, Man-Ki;Park, Jeong-Hill;Cho, Jung-Hwan
    • Archives of Pharmacal Research
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    • v.12 no.4
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    • pp.289-294
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    • 1989
  • A computer program which can differentiate compounds whose absorbance spectra are very similar was developed. The program. [SPECMAN PLUS], written in Pascal provides automated spectral comparison techniques, utilizing the values of Root Mean of Squares (RMS) of differences. This comparison routine of the program can deal with spectra of compounds different concentrations and different spectral recording resolutions. In addition, the program was designed applicable to any spectral data of digital form. The program was applied to the UV spectra of 13 pencillins and 5 cephalosporins, whose absorbance spectra are so similar. As a result, all compounds examined could be differentiated from each other.

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On the Mechanics of Impact Resistant Stitched Spectra/Vinylester Woven Laminate Composites (스티칭에 의한 Spectra/비닐에스테르 적층복합재료의 내충격성 변화에 관한 연구)

  • Lee, Seung-Ho;Gang, Tae-Jin;Uk, Jong-Il
    • Textile Science and Engineering
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    • v.31 no.1
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    • pp.32-36
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    • 1994
  • The mechanical and impact properties of the stitched Spectra composite was studied. The Spectra fiber reinforced vinylester composites were stitched with plain stitch to improve mechanical and impact resistant properties. The Spectra liber was used as a stitching thread and the composites were stitched twice in alternating sequence with plain stitch. The stitched composite showed different behavior with stitch densities in tensile and flexural properties. The effect of stitching has been changed with the mechanical properties measured under different restrained condition. The stitching has improved the preserving properties of the woven laminate composite structure by restricting the damage propagation.

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Beta particle energy spectra shift due to self-attenuation effects in environmental sources

  • Alton, Thomas Theakston;Monk, Stephen David;Cheneler, David
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1483-1488
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    • 2017
  • In order to predict and control the environmental and health impacts of ionizing radiation in environmental sources such as groundwater, it is necessary to identify the radionuclides present. Beta-emitting radionuclides are frequently identified by measuring their characteristic energy spectra. The present work shows that self-attenuation effects from volume sources result in a geometry-dependent shift in the characteristic spectra, which needs to be taken into account in order to correctly identify the radionuclides present. These effects are shown to be compounded due to the subsequent shift in the photon spectra produced by the detector, in this case an inorganic solid scintillator ($CaF_2:Eu$) monitored using a silicon photomultiplier. Using tritiated water as an environmentally relevant, and notoriously difficult to monitor case study, analytical predictions for the shift in the energy spectra as a function of depth of source have been derived. These predictions have been validated using Geant4 simulations and experimental results measured using bespoke instrumentation.

Effect of Smooth Hysteretic Behavior for Inelastic Response Spectra (비탄성 응답스펙트럼에 대한 완만한 곡선형 이력거동의 영향)

  • Song, Jong-Keol
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.1
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    • pp.1-9
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    • 2010
  • The actual hysteretic behavior of structural elements and systems is closer to smooth hysteretic behavior than piece-wise linear behavior. This paper presents a methodology for computing the constant-ductility inelastic response spectra for smooth hysteretic behaviors. The effect of the hysteretic smoothness on the inelastic response spectra for acceleration, displacement, and input energy is evaluated. The results indicate that increasing smoothness in the hysteretic behavior decreases the inelastic response spectra.

Simulation of 3QMAS NMR Spectra for Mordenite with the Point Charge Model

  • chae, Seen-Ae;Han, Oc-Hee
    • Journal of the Korean Magnetic Resonance Society
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    • v.9 no.1
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    • pp.67-73
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    • 2005
  • $^{27}AI$ triple quantum magic angle spinning (3QMAS) NMR spectra of several mordenite (MOR) sample were simulated with the point charge model method and compared with experimental 3QMAS spectra. Signal positions from different tetrahedral (T) sites in 3QMAS spectra are mainly governed by local structures of T sites such as T-O-T angles and T-O bond lengths. When preparation methods, cations in addition to Si/Al rations vary, the local structures of T sites in MOR change enough to alter signal patterns in 3QMAS of MOR. This inhibits to study the of Al distribution variation over 4 different T sites in mordenite during process such as dealumination by 3QMAS spectra.

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Comparative Evaluation of Nonlinear Seismic Responses of Bridge Structures Using Different Analysis Technique (해석방법에 따른 교량 구조물의 비선형지진응답 비교연구)

  • Kwon, Kyong-Il;Joe, Yang-Hee;Kim, Jae-Suk
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.396-404
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    • 2005
  • Nonlinear responses of structures may be obtained through three different methods. They are time-history analysis techniques, response spectrum method, and R-factor method. The nonlinear response spectrum method is frequently used in the practice, because the time history analysis method is time-consuming and complicated. There are two different approaches in obtaining the nonlinear response spectrum, which results in "constant displacement ductility spectra" and "constant damage spectra", respectively. The nonlinear response spectra of the various time-histories had been computed and the results were comparatively evaluated in this study. The study results showed that the existing constant displacement ductility spectra can induce unconservative design especially for the structures on soft soil base. This unconservatism can be removed by using the newly proposed constant damage spectra.

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