• Title, Summary, Keyword: uv-spectra

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On the UV and IR Spectra of Dioxane Lignin from Bamboo Culm (죽재(竹材) Dioxane Lignin의 UV, IR Spectrum에 대하여)

  • Moon, Chang-Kuck;Jo, Jong-Soo
    • Journal of the Korean Wood Science and Technology
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    • v.15 no.4
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    • pp.26-31
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    • 1987
  • The ultraviolet and infrared spectra of dioxane lignin from bamboo were investigated. 1. Spectrum curve type considerably resembled that of wood lignin. There were 3 absorption peak positions at 210nm(max. peak), at 260-270nm(shallow mini. peak), at 280nm(lower max. peak) as in the wood lignin spectra. 2. The lower minimum peak near at 280 nm is the typical peak of lignin. This peak does not exist exactly at 280 nm but from 282nm to 285nm in this bamboo UV spectra. The absorption intensities are equal in this region and the peak is not sharp. 3. The absorption band of aromatic nucleus is near at wave number $1550cm^{-1}$ in the IR spectra of bamboo lignin. The intensity at about 1040-$1130cm^{-1}$ and at about 1230-$1275cm^{-1}$ were similar in the hardwood lignin but reverse to that of softwood lignin spectrum.

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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.

Removal of Rhodamine B in Water by Ultraviolet Radiation Combined with Electrolysis(II) (전기분해와 UV 조사에 의한 수중 Rhodamine B의 제거(II))

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
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    • v.18 no.6
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    • pp.667-674
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    • 2009
  • This study has carried out to evaluate the effect of NaCI as electrolyte of single (electrolysis and UV process) and complex (electrolysis/UV) processes for the purpose of removal and mineralization of Rhodamine B (RhB) dye in water. It also evaluated the synergetic effect on the combination of electrolysis and UV process. The experimental results showed that RhB removal of UV process was decreased with increase of NaCl, while RhB removal of electrolysis and electrolysis/UV process was increased with increase of NaCI. The decolorization rate of the RhB solution in every process was more rapid than the mineralization rate identified by COD removal. The latter took longer time for further oxidation. Absorption spectra of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the bulk solution: concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the breakup of the chromophores. It was observed that RhB removal in electrolysis/UV process is similar to the sum of the UV and electrolysis. However, it was found that the COD of RhB could be degraded more efficiently by the electrolysis/UV process than the sum of the two individual process. A synergetic effect was demonstrated in electrolysis/UV process.

Calculated and Experimental UV and IR Spectra of Oligo-para-phenylenes

  • Park, Kwangyong;Lee, Tae-Won;Yoon, Min-Ju;Choe, Jong-In
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.531-538
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    • 2014
  • The quantum mechanical properties of a series of oligo-para-phenylenes (2-11) were characterized using DFT B3LYP/6-311G(d,p) calculations. The global minimum among the various torsional conformers of an oligo-p-phenylene is calculated to be a twist conformation. A less stable planar conformation, in which all the dihedral angles in oligo-p-phenylene are restricted to be planar, has also been calculated. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of the two different conformations (twisted and planar) of the oligo-p-phenylenes were analyzed. The energy differences between the HOMOs and LUMOs of the substrates are in accord with the maximum absorption peaks of the experimental UV spectra of 2-6. The calculated normal vibrational modes of 2-6 were comparable with their experimental IR spectra.

Intrinsic UV Reflection and Fluorescence Studies for Water Sorption in Polycarbonate, Polyurethane and Poly(Ethylene Terephthalate) Films

  • Kim Min Sun;Sung Chong Sook Paik
    • Fibers and Polymers
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    • v.6 no.2
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    • pp.127-130
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    • 2005
  • Intrinsic UV reflection and fluorescence behaviors of polycarbonate, polyurethane and poly(ethylene terephthalate) films were investigated in order to characterize the interaction of water in these films. During water sorption process, UV reflection spectra of polycarbonate and polyurethane films showed little peak position changes. Fluorescence emission spectra of polycarbonate films showed red spectral shifts from 332 nm with water immersion time. This red-shifted peak could be due to phenyl-2-phenoxybenzoate, which is one of the major thermal degradation products in polycarbonate. Fluorescence peaks of polyurethane films appeared at two different positions and the ratio of these peak intensities increased with increasing immersion time. In the case of PET films, the UV reflection spectrum showed the peak intensity around 340 nm to change in response to water sorption. The fluorescence near 388 nm probably due to ground state dimer exhibited sensitivity with water sorption, when excited at 340 nm.

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.

Development of Identification System of Derivative Spectra of Pharmaceuticals by Fast Hartley Transform (고속 하틀리 변환에 의한 의약품 미분스펙트럼의 확인 시스템의 개발)

  • 이숙연;노일협;박만기;박정일;조정환
    • YAKHAK HOEJI
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    • v.35 no.1
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    • pp.1-6
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    • 1991
  • Fast Hartley transform(FHT) was used for the identification of derivative UV spectra of pharmaceuticals, with the advantages of relatively shorter computing time of FHT and more precise results. The arccosine value of dot product of two vectors of normalized FHT coefficients calculated from two compared derivative spectra was a reasonable parameter for the spectral identification. Using this parameter, the similar patterns of derivative spectra of 13 penicillins can be differenciated from each other. The concentration difference and the minor contamination did not interfere the results of identification procedures. All these procedures of identification were accomplished successfully by the computer program, [SPECMAN PLUS] version 1.30, which was developed for this article.

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Paeonol-glycoside of the Root of Pycnostelma paniculatum Kitagawa (산해박의 배당체(配糖體)에 관한 연구(硏究))

  • Lee, Heum-Sook;Han, Dae-Suk;Kang, Tak-Lim
    • Korean Journal of Pharmacognosy
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    • v.11 no.2
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    • pp.66-68
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    • 1980
  • Paeonol-glycoside could be extracted and isolated from the fresh roots of Pycnostelma paniculatum Kitagawa and compared with paeonolide(paeonol-6-[L-arabinosyl]-${\beta}-D-glucoside)$ by IR and UV spectra. By saponification with mineral acid, it was known that isolated glycoside was composed of aglycon and sugar parts. Aglycon was identified by comparing with paeonol by TLC and UV spectra. Of two kinds of sugar, only glucose was identified by GLC.

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Photohysical Properties of New Psoralen Derivatives:Psoralens Linked to Adenine through Polymethylene Chains

  • Yoo, Dong-Jin;Park, Hyung-Du;Kim, Ae-Rhan;Rho, Young S.;Shim, Sang-Chul
    • Bulletin of the Korean Chemical Society
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    • v.23 no.9
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    • pp.1315-1327
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    • 2002
  • The model compounds, 8-methoxypsoralen-CH2O(CH2)n-adenine (MOPCH2OCnAd, n=2, 3, 5, 6, 8, and 10) in which 5 position of 8-methoxypsoralen (8-MOP) is linked by various lengths of polymethylene bridge to N9 of adenine. UV absorption spectra are identical with the sum of MOPCH2OC3 and adenine absorption spectra. Solvent effects on the UV absorption and fluorescence emission spectra indicate that the lowest excited singlet state is the $(\pi${\rightarrow}$\pi*)$ state. The spectral characteristics of the fluorescence of MOPCH2OCnAd are strongly dependent upon the nature of the solvents. The fluorescence emission spectra in aprotic solvents are broad and structureless due to the excimer formation through the folded conformation accelerated by hydrophobic ${\pi}-{\pi}$ stacking interaction. Increasing polarity of the protic solvents leads to higher population of unfolded conformation stabilized through favorable solvation and H-bonding, and consequently to an increase in the fluorescence intensity, fluorescence lifetime, and a shift of fluorescence maximum to longer wavelengths. The decay characteristics of the fluorescence in polar protic solvents shows two exponential decays with the lifetimes of 0.6-0.8 and 1.6-1.9 ns in 5% ethanol/water, while MOPCH2OC3 shows 0.5 and 1.7 ns fluorescence lifetimes. The long-lived component of fluorescence can be attributed to the relaxed species (i.e., the species for which the solvent reorientation (or relaxation) has occurred), while the short-lived components can be associated with the unrelaxed, or only partially relaxed, species.