• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.625-629
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• 2011

A quantitative analysis of the decreasing rate of the monomer and increasing rate of the polymerization was made by monitoring radiation level increments using Raman spectroscopy within the therapeutic radiation range for a normoxic polymethacrylic acid gel dosimeter. The gel dosimeter was synthesized by stirring materials such as gelatin, distilled water, methacrylic acid, hydroquinone and tetrakis phosphonium chloride at $50^{\circ}C$, and the synthesized gel was contained in a 10- mm diameter and 32-mm high vial to conduct measurement. 24 hours after gel synthesis, it was irradiated from 0 Gy to 20 Gy by 2 Gy using a Co-60 radiotherapy unit. With use of the Cryo FE-SEM, structural changes in the 0 Gy and 10 Gy gel dosimeters were investigated. The Raman spectra were acquired using 532-nm laser as the excitation source. In accordance with fitting the changes in C-COOH stretching (801 $cm^{-1}$), C=C stretching (1639 $cm^{-1}$) and vinyl $CH_2$ stretching (3114 $cm^{-1}$) vibrational modes for monomer and $CH_2$ bending vibrational mode (1451 $cm^{-1}$) for polymer, sensitive parameter S for each mode was calculated. The values of S for monomer bands and polymer band were ranged in $6.0{\pm}2.6$ Gy and $7.2{\pm}2.3$ Gy, respectively, which shows a relatively good conformity of the decreasing rate of monomer and the increasing rate of polymerization within the range of error.

• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.223-243
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• 1996

We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the $1200 - 1800{\AA}$ range where the temporal variation of solar irradiation is significant. The solar spectrum in this spectral range shows many emission lines, which cause a significant Swings effect. We derived fluorescence efficiencies of the bands as functions of heliocentric velocity and cometocentric distance using a high resolution spectrum of the sun. We compared our model with a spectrum of comet P/Halley obtained with the IUE, and estimated that the UV Swings effects are less than 20 fluorescence efficiencies for the most bands of the A-X system. We discuss the temporal variation of solar UV irradiation and its effects on the fluorescence efficiencies. The study of the A-X system also requites knowledge of vibrational and rotational fluorescent processes in the infrared and radio regions because the majority of CO molecules in the coma is in the ground rotational states. The solar infrared spectrum near 5 microns, where the fundamental band of CO occurs, contains strong absorption lines of the fundamental band and hot bands of CO and its isotopes. We derived fluorescence efficiencies of the infrared band as functions of heliocentric velocity and cometrocentric distance. The solar absorption lines near 5 microns cause a 20 reduction of the g-factor of the fundamental band at heliocentric velocities close to 0 km/sec. We discuss the effects of neutral and electron collisions on the fluorescence efficiencies of the infrared and UV bands.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1281-1281
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• 2001

Near-infrared (NIR) spectra have bean measured for high-density (HDPE), linear low-density (LLDPE), and low-density (LDPE) polyethylene in pellet or thin films. The obtained spectra have been analyzed by conventional spectroscopic analysis methods and chemometrics. By using the second derivative, principal component analysis (PCA), and two-dimensional (2D) correlation analysis, we could separate many overlapped bands in the NIR. It was found that the intensities of some bands are sensitive to density and crystallinity of PE. This may be the first time that such bands in the NIR region have ever been discussed. Correlations of such marker bands among the NIR spectra have also been investigated. This sort of investigation is very important not only for further understanding of vibration spectra of various of PE but also for quality control of PE by vibrational spectroscopy. Figure 1 (a) and (b) shows a NIR reflectance spectrum of one of the LLDPE samples and that of PE, respectively. Figure 2 shows a PC weight loadings plot of factor 1 for a score plot of PCA for the 16 kinds of LLDPE and PE based upon their 51 NIR spectra in the 1100-1900 nm region. The PC loadings plot separates the bands due to the $CH_3$ groups and those arising form the $CH_2$ groups, allowing one to make band assignments. The 2D correlation analysis is also powerful in band enhancement, and the band assignments based upon PCA are in good agreement with those by the 2D correlation analysis.(Figure omitted). We have made a calibration model, which predicts the density of LLDPE by use of partial least square (PLS) regression. From the loadings plot of regression coefficients for the model , we suggest that the band at 1542, 1728, and 1764 nm very sensitive to the changes in density and crystalinity.

• Animal Bioscience
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• v.36 no.8
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• pp.1190-1198
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• 2023

Objective: To our knowledge, there are few studies on the correlation between internal structure of fermented products and nutrient delivery from by-products from coffee processing in the ruminant system. The objective of this project was to use advanced mid-infrared vibrational spectroscopic technique (ATR-FT/IR) to reveal interactive correlation between protein internal structure and ruminant-relevant protein and energy metabolic profiles of by-products from coffee processing affected by added-microorganism fermentation duration. Methods: The by-products from coffee processing were fermented using commercial fermentation product, called Saus Burger Pakan, consisting of various microorganisms: cellulolytic, lactic acid, amylolytic, proteolytic, and xylanolytic microbes, for 0, 7, 14, 21, and 28 days. Protein chemical profiles, Cornell Net Carbohydrate and Protein System crude protein and CHO subfractions, and ruminal degradation and intestinal digestion of protein were evaluated. The attenuated total reflectance-Ft/IR (ATR-FTIR) spectroscopy was used to study protein structural features of spectra that were affected by added microorganism fermentation duration. The molecular spectral analyses were carried using OMNIC software. Molecular spectral analysis parameters in fermented and non-fermented by-products from coffee processing included: Amide I area (AIA), Amide II (AIIA) area, Amide I heigh (AIH), Amide II height (AIIH), α-helix height (αH), β-sheet height (βH), AIA to AIIA ratio, AIH to AIIH ratio, and αH to βH ratio. The relationship between protein structure spectral profiles of by-products from coffee processing and protein related metabolic features in ruminant were also investigated. Results: Fermentation decreased rumen degradable protein and increased rumen undegradable protein of by-products from coffee processing (p<0.05), indicating more protein entering from rumen to the small intestine for animal use. The fermentation duration significantly impacted (p<0.05) protein structure spectral features. Fermentation tended to increase (p<0.10) AIA and AIH as well as β-sheet height which all are significantly related to the protein level. Conclusion: Protein structure spectral profiles of by-product form coffee processing could be utilized as potential evaluators to estimate protein related chemical profile and protein metabolic characteristics in ruminant system.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.54.1-54.1
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• 2016

Stellar wind and radiation pressure from massive stars can trigger the formation of new generation of stars. The sequential age distribution of stars, the morphology of cometary globules, and bright-rimmed clouds have been accepted as evidence of triggered star formation. However, these characteristics do not necessarily suggest that new generation of stars are formed by the feedback of massive stars. In order to search for any physical connection between star forming events, we have initiated a study of gas and stellar kinematics in NGC 1893, where two prominent cometary nebulae are facing toward O-type stars. The spectra of gas and stars in optical and near-infrared (NIR) wavelength are obtained with Hectochelle on the 6.5m MMT and Immersion GRating INfrared Spectrograph on the 2.7m Harlan J. Smith Telescope at McDonald observatory. In this study, the radial velocity field of gas across the cluster is investigated using $H{\alpha}$ and [N II] ${\lambda}$ 6584 emission lines, and that of the cometary nebula Sim 130 is also probed using 1-0 S(1) transition line of $H_2$. We report a distinctive velocity field of the cometary nebulae and many ro-vibrational transitions of $H_2$ even at high energy levels in the NIR spectra. These properties indicate the interaction between the cometary nebulae and O-type stars, and this fact can be a clue to triggered star formation in NGC 1893.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1519-1524
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• 2008

We have investigated the photophysics of the acetone radical cation in the vacuum ultraviolet energy region by multiphoton ionization combined with time-of-flight mass spectrometry in a cluster beam. We have found that the loss of methyl radical from the acetone radical cations is remarkably suppressed at 10.5 eV when they are solvated by a few neutral acetone molecules. The cluster ion mass spectra obtained by nanosecond and picosecond laser pulses reveal that there are intermolecular processes, occurring in several tens of picoseconds, which are responsible for the survival of the acetone cations in clusters. This remarkable solvation effect on the yield of the methyl radical loss from the acetone cation can be rationalized by the intracluster vibrational energy redistribution and the self-catalyzed enolization which compete with the methyl radical loss process.

• The Journal of the Convergence on Culture Technology
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• v.4 no.2
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• pp.155-160
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• 2018

In this study, the experiments for surface enhancement of silver mirror substrates were done, where we checked the characteristics of silver surface made by Tollen's and ${\gamma}$- irradiation method. The surface enhancement of Indigo carmine was analyzed by silver mirror and silver sol surfaces. The assignments of the vibrational bands shown in SERS spectra are given based on both literature and the semi-empirical calculations at the PM3 methods. We deduced that the adsorption orientation of Indigo carmine was little tilted perpendicular to the silver surfaces by using of the surface selection rules.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.2
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• pp.116-121
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• 2000

The temperature profiles of gas phase and the concentration profiles of GaN precursors in an inverted OMVPE reactor have been carried out by in-situ Raman spectroscopy. Pure rotational Raman scattering from the carrier gas (rd) was used to determine the temperature profiles in the reactor, and a large temperature gradient perpendicular the susceptor surface was observed. The homogeneous gas phase decompositions of the OMVPE precursors were investigated by the vibrational Raman spectra, and it was found that the pyrolyses of $NH_3$ and TMGa begin above 800 K and 650 K, respectively, but a noticeable amount of precursors remain undecomposed even in the region very close to the susceptor.

• Journal of The Korean Astronomical Society
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• v.34 no.1
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• pp.35-40
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• 2001

For the planned experiments of Korea Sounding Rocket-III (KSR-III), we have constructed a model of MUV dayglow in the mid-latitude. The model computes relative intensities of individual emission lines in the Vegard-Kaplan and 2PG band systems of $N_2$ in the wavelength range of 2500-3500${\AA}$. In addition to the emission lines, solar scattered continuum was computed by an extended LOWTRAN7 code, in which we have included solar scattering in altitudes higher than 100 km by using MSIS90 thermosphere model. Ratios among vibrational bands of VK and 2PG system, were computed from the observed MUV dayglow spectra of Cleary et al. (1995). The model provides MUV dayglow intensitiy profiles with a wavelength resolution of 3.13${\AA}$ as a function of altitude. The computed intensity profiles have been utilized in designing the KSR-III airglow photometers.

• Journal of Integrative Natural Science
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• v.3 no.3
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• pp.153-156
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• 2010

Oxidation behaviors of porous silicon were investigated by the measurement of area of $SiO_2$ vibrational peaks in FT-IR spectra during thermal oxidation of porous silicon at corresponding temperatures. Visible photoluminescent porous silicon samples were obtained from an electrochemical etch of n-type silicon of resistivity between 1-10 ${\Omega}/cm$. The etching solution was prepared by adding an equal volume of pure ethanol to an aqueous solution of HF. The porous silicon was illuminated with a 300 W tungsten lamp for the duration of etch. Etching was carried out as a two-electrode galvanostatic procedure at applied current density of 200 $mA/cm^2$ for 5 min. The porosity of samples prepared was about 80%. After formation of porous silicon, the samples were thermally oxidized at $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$, respectively. The growth rate of $SiO_2$ layer of porous silicon was investigated by using FT-IR spectroscopy. The effect of oxidation of porous silicon was presented.