• Title/Summary/Keyword: ultraviolet absorption

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CO TO H2 RATIO OF INTERSTELLAR MOLECULAR CLOUDS IN THE DIRECTIONS OF EARLY TYPE STARS (초기형 별 방향 성간운의 CO 와 H2 비율 계산)

  • Park, Jae-Woo;Lee, Dae-hee;Min, Kyoung-Wook
    • Journal of Astronomy and Space Sciences
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    • v.21 no.4
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    • pp.243-248
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    • 2004
  • We present measurements of interstellar CO absorption lines in the spectra of 7 early-type stars that were observed with the FUSE(Far Ultraviolet Spectroscopic Explore.) Among 54 early-type target stars in the Galactic disk and halo observed with the BBFS(Berkeley Extreme and Far-ultraviolet Spectrometer), we choose 7 program stars (HD 37903, HD 97991, HD 149881, HD 156110, HD 164794, HD 214080 and HD 219188) which have only a single velocity component in the high-resolution optical measurements, in order to avoid line blending. To analyze the CO molecule, we select the E-X (0-0) band at $1076{\AA}$, which has a large oscillate. strength and is not blended with other interstellar absorption lines. We detect the CO absorption lines in three (HD 37903, HD 164794, and HD 214080) out of seven targets, and derive CO column densities for those targets. We also estimated the CO to $H_2$ ratios toward the three stars, based on the previously estimated $H_2$ column densities.

The Effect of Benzophenone Derivatives on the Shielding of Ultraviolet Rays and Light-fastness of the Dyed Fabrics (벤조페논 유도체의 자외선 차단 효과 및 염색물의 일광견뢰도에 미치는 영향)

  • 김종규;김태경;박태수;임용진
    • Textile Coloration and Finishing
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    • v.10 no.4
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    • pp.53-61
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    • 1998
  • The absorptions of ultraviolet rays of benzophenone derivatives were investigated in terms of the position of substituent, especially hydroxyl group. When the derivatives were added to the aqueous solution of Rhodamin B, which has very low light-fastness, all of them delayed the photofading of Rhodamin B solution. But on the fabrics, only the derivatives with the hydroxyl group at 2-position showed the good ability of ultraviolet rays absorption. The benzophenone derivatives absorb ultraviolet rays to form a hydrogen bond between hydroxyl group and carbonyl group, and return to their original structure by releasing heat energy. In solution, the derivatives can form a intermolecular hydrogen bond, and absorb the ultraviolet rays. But on the fabric, the intermolecular hydrogen bond is impossible, only hydroxyl group of 2-position forms a intramolecular hydrogen bond, and that makes the derivatives on the fabric absorb ultraviolet rays.

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The chemical effects of milking machine detergents on the rubber composition of the newly-developed teat cup liners (착유기 세척제가 신개발 젖소 유두컵 라이너용 고무조성물 재질에 미치는 화학적 영향)

  • Lee, Jeong-Chi
    • Korean Journal of Veterinary Service
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    • v.41 no.2
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    • pp.125-131
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    • 2018
  • This study investigated the effects of the alkaline detergent and acid rinse used for cleaning milking machines on the rubber composition of the newly-developed teat cup liners. The samples prepared for use in the clean-in-place process were analyzed by ultraviolet spectrophotometer, ion chromatography and liquid chromatography. In the absorption spectrum of the first sample solution, the form of absorbance or absorption peak was largely different, compared to the absorption spectrum of alkaline detergent alone, but in the absorption spectra of the second and third sample solutions, the absorbance decreased, which was similar to the absorption spectrum in the pure acid detergent. In the ion chromatogram, two main peaks only, which might be shown by the pure alkaline detergent alone, were measured. In the liquid chromatograms, however, new peaks were observed in addition to the two main peaks caused by the pure alkaline detergent alone, which suggested that various molecular materials were created or eluted from the liner by the reaction with the alkaline detergent, but when washed with the acid detergent, any ion species were not produced. Therefore, we propose that an acid rinse should be applied, after cleaning the milking machine with the alkaline detergent.

Analysis of Ozone Concentration by TD and Q-mass Method

  • Lee, Dong-Gyu;Lee, Joon-Ung
    • Transactions on Electrical and Electronic Materials
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    • v.5 no.4
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    • pp.161-165
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    • 2004
  • In order to get oxidizing power enough for growth of a superconductive thin film with oxide gas, concentrated ozone was used. As a method for concentrating ozone, a method for concentrating ozone by adsorbing ozone selectively into silica-gel beads is adopted, and this concentration is analyzed by the ultraviolet absorption method, the thermal decomposition method and the Q-mass analyzing method. Thermal decomposition method is most effective for measurement of a high concentration of ozone. Ozone as concentrated by the adsorption method got to have a concentration of 97 mol % at the maximum, and it was identified that the concentration of the ozone gas was stable for the time while a thin film was formed.

Studies on Toxic Metabolites Occurring in Foods(I) Screen test of Aflatoxin in Some Korean Fermented Soybean Foods (식품중(食品中) 유독성(有毒性) 대사산물(代謝産物)에 관(關)하여(제(第) 1 보(報)) 수종(數種)의 한국(韓國) 대두발효식품중(大豆醱酵食品中)에 Aflatoxin 유무(有無)의 검색(檢索)에 관(關)하여)

  • Lee,, Tai-Young;Lee,, Sang-Kyu
    • Korean Journal of Food Science and Technology
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    • v.1 no.1
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    • pp.78-84
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    • 1969
  • An attempt has been made to investigate the possible occurrence of aflatoxins, a group of micotoxin which are toxic metabolites produced by Aspergillus flavus, and aflatoxin like substances in fungal fermented soybean products such as meju and soybean paste. Chloroform extracts from 15 samples which has been defated with petroleum ether are subjected to separations with thin-layer chromatography on silica gel washed with methanol prior to film coating, improves the chromatographic separation and ultraviolet absorption spectral identification. In addition to fluorescencing spot having an Rf value which is same as aflatoxin $B_1$, many of the fluorescencing spots have been occurred in every sample examined. Each fluorescencing spot is scratched and the ethanol extracts are subjected to further separation with thin-layer chromatography. Each fluorescence substance is eluted with ultra violet transparent absolute ethanol and the ultraviolet absorption spectra are checked. None of the absorption curve of eluates shsow accordance with the curve of aflatoxin. 2, 4-Dinitrophenyl hydrazine reagent, Tollen's reagent and ninhydrin reagent are applied on the chromatogram- The data show that aflatoxin is not present in any of the fungal preparations examined.

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Preparation of Polyynes by the Laser Ablation of Graphite in Water and Organic Solvents

  • Shin, Seung-Keun;Park, Seung-Min
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.597-600
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    • 2012
  • Polyynes were formed by laser ablation of a graphite target in deionized water ($H_2O$ and $D_2O$) and various organic solvents such as acetonitrile, n-hexane, and c-hexane and were identified by analyzing ultraviolet (UV) absorption and Raman spectra. We assigned the major UV absorption peaks that coincided with the electronic transitions corresponding to linear polyyne chains. The UV absorption peak intensities of a polyyne solution decreased as the holding temperature of the solution increased. Also, the absorption spectra of polyynes obtained by laser ablation of a graphite target at different volume fractions of $H_2O$ and $D_2O$ were examined.

The Absorption Spectra of Substituted Azoxybenzenes and the Additivity of the their Absorption Maxima (Azoxybenzene 系化合物들의 分光學的硏究 및 그 最大吸收波長의 加成性)

  • Hahn, Chi-Sun
    • Journal of the Korean Chemical Society
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    • v.6 no.2
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    • pp.170-175
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    • 1962
  • The ultraviolet and visable absorption spectra of trans, cis-azoxybenzene, substituted azoxybenzenes and their conjugate acids have been studied. The 320-350$m{\mu}$ main bands of free-base of azoxybenzenes are due to ${\pi}{\to}{\pi}^{\ast}$ transition. These bands of their conjugate acids shown bathochromic shift into visible range. The following emperical relationship between absorption maxima of the main bands was found. ${\lambda}_{max}={\lambda}^{\circ}_{max}+{\Delta}{\lambda}_x+{\Delta}{\lambda}_y$ This relationship in terms of wave number is also hold in good agreement. ${\nu}={\nu}_{\circ}-({\Delta}{\nu}_x+{\Delta}{\nu}_y)$

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A Study on the UV-cut Properties of Cotton Fabrics Treated with UV-absorber (자외선 흡수제 처리 면직물의 소비성능 개선(제1보) - 자외선 차단성능에 관한 연구 -)

  • 강미정;권영아
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.5
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    • pp.925-932
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    • 2001
  • The influence of ultraviolet(UV)-ray in sun light on human skin has been noted. Textiles can provide protection against harmful UV-radiation. Normally UV-absorbing finishes are used to get better protection. The purpose of this study is to evaluate the UV-cut properties of cotton fabrics treated with UV-absorber. 2,2-dihydroxy-4,4-dimethoxbenzophenone, as UV-absorber was applied to 100% cotton fabric. Reagents added in finishing solution were Triton X-100, polyethylene glycol 400, and $MgCl_2{\cdot}6H_2O$, and C.I. Direct Red 81. Both untreated and treated cotton fabrics were exposed to a xenon arc lamp for 20 and 80 hours. UV absorption spectra of finishing solutions and UV transmission spectra of fabrics were measured by the UV/VIS spectrophotometer. The results of this study can be summarized as follows. The results of this study can be summarized as follows. Absorption and the related transmission spectra were modified in a controlled way with UV-absorber. Absorption effect of UV-absorber was improved by adding Triton X-100, PEG 400, and $MgCl_2{\cdot}6H_2O$ in finishing solution. The UV absorption of finishing solution was in the following order: U/D/T/P/M>D/T/P/M> D/T> D/P, D>U/T/P/M>U/T>T/P/M>T. The UV transmittance of cotton fabrics was remarkably decreased by the application of UV-absorber and additives. The UV-cut properties were most improved by the application of U/D/T/P/M.

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Measurement of Hydroxyl Radical Density at Bio-Solutions Generated from the Atmospheric Pressure Non-Thermal Plasma Jet

  • Kim, Yong Hee;Hong, Young June;Uhm, Han Sub;Choi, Eun Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.494-494
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    • 2013
  • Atmospheric pressure non-thermal plasma of the needle-typed interaction with aqueous solutions has received increasing attention for their biomedical applications [1]. In this context, surface discharges at bio-solutions were investigated experimentally. We have generated the non-thermal plasma jet bombarding the bio-solution surface by using an Ar gas flow and investigated the emission lines by OES (optical emission spectroscopy) [2]. Moreover, The non-thermal plasma interaction with bio-solutions has received increasing attention for their biomedical applications. So we researched, the OH radical density of various biological solutions in the surface by non-thermal plasma were investigated by Ar gases. The OH radical density of DI water; deionized water, DMEM Dulbecco's modified eagle medium, and PBS; 1x phosphate buffered saline by non-thermal plasma jet. It is noted that the OH radical density of DI water and DMEM are measured to be about $4.33{\times}1016cm-3$ and $2.18{\times}1016cm-3$, respectively, under Ar gas flow 250 sccm (standard cubic centimeter per minute) in this experiment. The OH radical density of buffer solution such as PBS has also been investigated and measured to be value of about $2.18{\times}1016cm-3$ by the ultraviolet optical absorption spectroscopy.

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Photocatalytic Properties of TiO2 Thin Films Prepared by RF Sputtering (RF Sputtering법으로 제조된 TiO2 박막의 광촉매 특성)

  • Jeong, Min-ho;Jin, Duk-yong;Hayashi, Y.;Choi, Dae-kue
    • Korean Journal of Materials Research
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    • v.13 no.3
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    • pp.185-190
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    • 2003
  • Titanium dioxide films were prepared by RF sputtering method on glass for various oxygen partial pressures at power 270 W. The crystal structure, photocatalytic property and the hydrophilicity of $TiO_2$thin film the deposition conditions were investigated. Crystallized anatase phase was observed in $TiO_2$film deposited at the ratio of oxygen partial pressure 10% and 20% for 2 hrs. As the increase of deposition time, the grain size and void size of $TiO_2$film have increased and also $V_2$films have been good crystallinity. The ultraviolet-visible light absorption of $TiO_2$films was increased with increasing of deposition time and occured chiefly at the wavelength between 280 and 340 nm. The absorption band was shifted to a longer wave length as deposition time increased. Water contact angle on the X$TiO_2$film of anatase structure was decreased with increasing ultraviolet illumination time and became lower than $11^{\circ}$ from $83^{\circ}$. When hydrophilic $TiO_2$film changed by enough ultraviolet illumination was stored in the dark, the film surface gradually turned to hydrophobic state.