• Title/Summary/Keyword: UV -Vis spectra

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Photoisomerization of Cellulose Derivatives Obtained from Homogeneous System (균질계에서 얻은 셀룰로오스 유도체의 광이성질화 현상 연구)

  • No, Young-Ran;Park, Keun-Ho;Lee, Soo
    • Journal of the Korean Applied Science and Technology
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    • v.17 no.4
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    • pp.273-278
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    • 2000
  • Cellulose tosylate(CT) was prepared by reaction of cellulose with p- toluenesulfonylchloride in DMAc/LiCl homogeneous system. In order to study a reversible photoisomerization of disperse red 1(DR-1) attached on natural polymer, cellulose tosylate containing DR-1(DR-1/CT adduct) was prepared at $110^{\circ}C$ in DMAc, and the changes of UV/Vis spectra of its solutions and thick film were investigated by alternate irradiation technique. Form the UV/Vis spectra of DR-1/CT adduct dissolved in cosolvents, such as DMAc, DMAc/THF, DMAc/benzene, and DMAc/chloroform and irradiated with 360 nm and 450 nm ligths, we found out changes of UV/Vis spectra were reversible in all solvents systems and we found out changes of UV/Vis spectra were reversible at thick film, also.

The Dyeing Properties of Korean Knotweed Extract(Ⅱ) - The UV-visible Spectrophotometric Characteristics of Korean Knotweed Extracts - (호장근 추출액에 의한 염색성(Ⅱ) - 호장근 추출액의 자외 · 가시부 분광 특성 -)

  • Kim, Mi Suk;Choe, Seok Cheol
    • Textile Coloration and Finishing
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    • v.13 no.5
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    • pp.10-10
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    • 2001
  • The Purpose of this study was to investigate spectrophotometric characteristics of Korean knotweed extracts. The properties were evaluated by it′s extracting solvent, effect of metallic ion, variations of pH values and effect of light exposure. The results were as following; The highest absorbance was found in methanol extract of Korean knotweed, while the lowest absorbance was carbon tetrachloride extract. The UV-vis. spectra of Korean knotweed colors in several solvents showed hypsochromic shift of n-π/sup */ transition with the polarity of solvent. Absorbance and peak of UV-vis. spectra of Korean knotweed colors became lower and broader by addition of metallic ion. The light stability in irradiation with xenon ]amp of the color solution with Cu were higher than those of Al and Fe. The UV-vis. spectra of Korean knotweed extracts in various pH values showed bathochromic shift under alkaline condition, and their peaks disappeared after 5 hours exposure.

The Dyeing Properties of Korean Knotweed Extract( II ) - The UV-visible Spectrophotometric Characteristics of Korean Knotweed Extracts - (호장근 추출액에 의한 염색성(II) -호장근 추출액의 자외 . 가시부 분광 특성 -)

  • 김미숙;최석철
    • Textile Coloration and Finishing
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    • v.13 no.5
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    • pp.298-305
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    • 2001
  • The Purpose of this study was to investigate spectrophotometric characteristics of Korean knotweed extracts. The properties were evaluated by it's extracting solvent, effect of metallic ion, variations of pH values and effect of light exposure. The results were as following; The highest absorbance was found in methanol extract of Korean knotweed, while the lowest absorbance was carbon tetrachloride extract. The UV-vis. spectra of Korean knotweed colors in several solvents showed hypsochromic shift of $n->\pi^*$ transition with the polarity of solvent. Absorbance and peak of UV-vis. spectra of Korean knotweed colors became lower and broader by addition of metallic ion. The light stability in irradiation with xenon ]amp of the color solution with Cu were higher than those of Al and Fe. The UV-vis. spectra of Korean knotweed extracts in various pH values showed bathochromic shift under alkaline condition, and their Peaks disappeared after 5 hours exposure.

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A Study on photoisomerization of cellulose acetate containing disperse red 1 (Disperse red 1을 함유하고 있는 셀룰로오스 아세테이트의 광이성화에 관한 연구)

  • Lee, Soo;Park, Keun-Ho;Jung, Dong-Soon
    • Journal of the Korean Applied Science and Technology
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    • v.16 no.4
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    • pp.273-279
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    • 1999
  • In order to study a reversible photoisomerization of disperse red l(DR 1) attached on natural polymers, cellulose acetate containing DR l(DR 1/CA adduct) was prepared, and the changes of UV/VIS spectra of its solution(benzene, DMAc). thick film, and LB film were investigated by alternate irradiation with two different wave length lights. DR 1/CA adduct was prepared through tosylation of partially hydrolyzed cellulose acetate followed by reaction with DR 1 at $100^{\circ}C$ in pyridine. From the UV/VIS spectra of DR 1/CA adduct dissolved in DMAc solvent including phosphoglyceride before and after irradiation at 360nm and 45Onm, we found out the changes of UV/VIS spectra were reversible. In addition, the change of UV/VIS spectra of this adduct solution was strongly depended on the sorts of solvents and temperature. As the temperature was increased, UV/VIS spectra of this adduct solution in DMF showed blue shift. These results provided this solution could be applied to a temperature sensor. In the thick film case, we also obtained similar results with solution case. LB monolayer and trilayer from DR 1/CA adduct was obtained by scattering the solution including phosphoglyceride on water surface at the surface pressure of 8mN/m. After irradiation on that LB monolayer and trilayer, the reversible photoisomerization was also detected. From these results we concluded DR 1/CA adduct was suitable for the application to data storage and optical switch, etc.

UV-Vis Spectra of N, N'-Bis(4′-Aminophenyl)-1,4-quinonenediimine Doped With $H_{4}SiW_{12}O_{40}$

  • Jian Gong;Cui, Xiu-Jun;Chen, Ya-Guang;Xie, Zhong-Wei;Qu, Lun-Yu
    • Macromolecular Research
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    • v.12 no.1
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    • pp.22-25
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    • 2004
  • We have synthesized aniline oligomer composites by using heteropoly acid (H$_4$SiW$_{12}$O$_{40}$ ) as a dopant. The doping and dedoping processes of the aniline oligomer composites were investigated with the aid of UV- Vis spectra. The bands of the aniline oligomer at 572 nm weakened or disappeared, and the bands at 268, 412, and 771 nm appeared, after the aniline oligomer was doped. When the solution of the aniline oligomer doped with H$_4$SiW$_{12}$O$_{40}$ was kept at lower values of pH, the aniline oligomer could not be dedoped by dilution. The turning point of doping and dedoping occurred at pH 5.5. The band at 771 nm shifted towards longer wavelengths when the aniline oligomer composites were synthesized using acetone as the solvent. This observation indicates that the molecular chain became stretched. In addition, we also investigated the change of the electronic absorption spectra of the composites with respect to the time laid up.id up.

Emission Spectroscopy of Unstable Molecules using a Fourier Transform Spectrometer (Fourier Transform 분광기를 이용한 불안정한 분자의 방출분광학)

  • Sang Kuk Lee;Un Sik Kim
    • Journal of the Korean Chemical Society
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    • v.37 no.4
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    • pp.371-377
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    • 1993
  • Fourier Transform UV/VIS spectrometer has been modified for emission spectroscopy with the technique of supersonic expansion, in which the unstable molecular radical $CH_3S$ has been generated in a jet by a high voltage DC discharge. The fluorescence spectra of the supersonically cooled radical have been recorded on a Fourier Transform UV/VIS spectrometer. The ratio of signal to noise of the spectra has been improved substantially. Also the rotational structure has been clearly resolved for $CH_3S$ molecular radical.

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Photocatalytic Performance of ZnS and TiO2 Supported on AC Under Visible Light Irradiation

  • Meng, Ze-Da;Cho, Sun-Bok;Ghosh, Trisha;Zhu, Lei;Choi, Jong-Geun;Park, Chong-Yeon;Oh, Won-Chun
    • Korean Journal of Materials Research
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    • v.22 no.2
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    • pp.91-96
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    • 2012
  • AC and ZnS modified $TiO_2$ composites (AC/ZnS/$TiO_2$) were prepared using a sol-gel method. The composite obtained was characterized by Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, scanning electron microscope (SEM) analysis, and according to the UV-vis absorption spectra (UV-vis). XRD patterns of the composites showed that the AC/ZnS/$TiO_2$ composites contain a typical single and clear anatase phase. The surface properties as observed by SEM present the characterization of the texture of the AC/ZnS/$TiO_2$ composites, showing a homogenous composition in the particles showing the micro-surface structures and morphology of the composites. The EDX spectra of the elemental identification showed the presence of C and Ti with Zn and S peaks for the AC/ZnS/$TiO_2$ composite. UV-vis patterns of the composites showed that these composites had greater photocatalytic activity under visible light irradiation. A rhodamine B (Rh.B) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of Rh.B was determined using UV/Vis spectrophotometry. An increase in the photocatalytic activity was observed. From the photocatalytic results, the excellent activity of the Y-fullerene/$TiO_2$ composites for the degradation of methylene blue under visible irradiation could be attributed to an increase in the photo-absorption effect caused by the ZnS and to the cooperative effect of the AC.

Studies on the Natural dyes( I ) -extraction and UV, VIS spectrum of coloring matter of gromwell- (천연염료에 관한 연구 ( I ) -자근색소의 추출 및 자외가시분광특성-)

  • Cho Kyung Rae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.11 no.3 s.25
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    • pp.25-32
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    • 1987
  • The purpose of this study is to investigate optical behaviour of coloring matter of gromwell -extracted by water, acetic acid/methanol, and the other solvents. The results were as following: UV, VIS spectra of the solution of coloring matter of gromwell extracted by water at below $80^{\circ}C$ did not reveal in the range of the visible light wavelength and coloring matter of gromwell decomposed to blue particle at $95^{\circ}C$. The solution extracted by acetic acid/methanol was tinged with reddish purple and its spectra shifted to the longer wavelength according to increase of the solvent temperature. The color of the solution extracted by water became extinct as time went by, but that extracted by acetic acid/methanol kept up original color. In case of dried gromwell, extraction by acetic acid/methanol was easier than by water, and variation of spectra did not appear but showed hypochromic shift.

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Spectroscopic Characteristics of Gemstones with Color Change Effect (변색 효과 보석들의 분광학적 특성)

  • Ahn, Yong-Kil;Seo, Jin-Gyo;Park, Jong-Wan
    • Journal of the Mineralogical Society of Korea
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    • v.22 no.2
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    • pp.81-86
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    • 2009
  • The luminescence and fluorescence were investigated by photoluminescence spectroscopy for six gemstones which exhibit color change effect. The shape of luminescence peaks appears different when observed by a photoluminescence spectroscopewith a 514 nm Ar laser source. However, it was not possible to observe the difference in the spectra between the natural and synthetic origins for the same type of gemstones. It was found that the photoluminescence spectrum was related to the crystal structure of the stones. Photoluminescence spectra using a 325 nm He-Cd source reveal that fluorescence is relatively strong for synthetic alexandrite, synthetic color change sapphire and natural alexandrite comparing to the rest of gemstones examined.

The Analysis of Lanthanides Using UV-VIS Spectrometer (UV-VIS 흡광광도법으로 란탄족원소들의 정량분석에 관한 연구)

  • Ji, Bong Il;Kim, Ha Seok;Ha, Yeong Gu
    • Journal of the Korean Chemical Society
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    • v.34 no.6
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    • pp.616-621
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    • 1990
  • The spectrophotometric methods for the determination of Nd, Pr, Sm, Eu, Ho, Er were developed, using the multicomponent method of absorption spectra cointerference. The absorption spectra of individual Nd, Pr, Sm, Eu, Ho, Er, mixture of Sm, Eu, Ho, Er in hydrochloric acid solutions were investigated, and also a band register which includes the molar absorptions for all trivalent Nd, Pr, Sm, Eu, Ho and Er absorption band maxima were measured. The spectrophotometric determination of Nd, Pr, Sm, Eu, Ho and Er were investigated using the analytically significant absorption bands at 444.2, 575.1, 401.7, 394.2, 416.6, and 379.7 nm, respectively.

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