• Title, Summary, Keyword: uv-spectra

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Dyeing of Cotton Fabrics using Residual Parts of Cultivated Pteridium aquilinum (재배 고사리 부산물을 활용한 면직물의 염색)

  • Lee, Hyesun;Kang, Eunyoung
    • Textile Coloration and Finishing
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    • v.26 no.1
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    • pp.53-62
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    • 2014
  • This study examined the dyeability, color fastness and functionality of cotton fabrics dyed with residual parts of cultivated Pteridium aquilinum. UV-Vis absorption spectrum, TLC and FT-IR spectra analysis showed that colorants of Pteridium aquilinum are a mixture of pyrogallol tannin and catechol tannin. Optimum dyeing conditions was confirmed colorant concentration of 500% at $100^{\circ}C$ for 60 minutes. Color fastness followed to washing, rubbing, perspiration and light as 4-5, 5, 4-5(acidic), 3-4(alkaline) and 2, respectively. Deodorization rates of ammonia($NH_3$) and acetic acid ($CH_3COOH$) were analyzed 88.8% and 78.0%. UV protection rate was 94.2% of UV-A and 96.8% of UV-B. UV protection factor(UPF) was 27. Therefore residual parts of cultivated Pteridium aquilinum could be used for a new functional colorant.

Separating of Falcarinol from Acanthopanax senticosus (가시오가피(Acanthopanax senticosus)에서 polyacetylene계 화합물인 falcarinol의 동정)

  • Kim, Seong-Ju;Chang, Kyu-Seob
    • Korean Journal of Food Science and Technology
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    • v.37 no.3
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    • pp.360-363
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    • 2005
  • To detect falcarinol in Acanthopanax senticosus, its stem and bark were extracted with methanol fractionated with petroleum ether and diethyl ether, and separated by silica gel column chromatography, Resulting six crude samples were compared with standard falcarinol through TLC on silica gel plates. Fraction 6 showed $R_{f}$ value of 0.46 similar to that of standard falcarinol. Through analytical reverse phase HPLC/PDA, UV spectra of standard falcarinol and traction 6 recorded between 200 and 340 nm showed identical peaks and UV spectra patterns. GC/MS revealed standard falcarinol and fraction 6 have equal retention times of 7.4 and 8.5 min before and after TMS-derivatization, respectively. Standard falcarinol and fraction 6 showed more similar spectrum patterns after TMS-derivatization than before. These results confirm presence of falcarinol in A. senticosus.

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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Analyses of Additives Applied in a Polycarbonate (폴리카보네이트에 사용된 첨가제의 분석)

  • Kim, Seog-Jun
    • Analytical Science and Technology
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    • v.13 no.3
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    • pp.282-290
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    • 2000
  • In this study, polymer additives were extracted and separated by Soxhlet extraction method and the dissolution-precipitation method from a polycarbonate (optical grade) which completely absorbed UV light below 390 nm. Analytical techniques such as UV-Vis spectroscopy, FT-IR, and HPLC were applied to analyze additives in polycarbonate. Separated materials from the polycarbonate may be a complex mixture containing additives such as UV stabilizer, antioxidants (primary and secondary), monomers, and oligomers. Several compounds such as bisphenol A, Irganox 1010, and Cyasorb UV-5411 were identified by chromatograms and UV spectra obtained from RP HPLC analysis using Bondapak $C_{18}$ column, methanol mobile phase, and a photodiode array (PDA) detector. Also, the content of UV-5411 in the polycarbonate was about 0.12 wt% by a quantitative analysis through UV spectroscopy.

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Improvement in Long-Term Stability and Photovoltaic Performance of UV Cured Resin Polymer Gel Electrolyte for Dye-Sensitized Solar Cell

  • Park, Geun Woo;Hwang, Chul Gyun;Jung, Jae Won;Jung, Young Mee
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4093-4097
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    • 2012
  • We introduced a new UV-cured resin polymer gel as an electrolyte for dye-sensitized solar cells (DSSCs) that is cured with UV irradiation to form a thin film of UV-cured resin polymer gel in the cells. The gel film was characterized and its potential for use as an electrolyte in DSSCs was investigated. This new UV-cured resin polymer gel was successfully applied as a gel polymer electrolyte in DSSCs overcoming the problems associated with the liquid electrolytes in typical DSSCs. The effect of ${\gamma}$-butylrolactone (GBL) on the long-term stability and photovoltaic performance in DSSCs using this UV-cured resin polymer gel electrolyte was also investigated. The results of the energy conversion efficiency, ionic conductivity and Raman spectra of the UV-cured resin polymer gel electrolyte with the addition of 6 wt % GBL to the UV-cured resin polymer electrolyte showed good long-term stability and photovoltaic performance for the DSSCs with the UV-cured polymer gel electrolyte.

ON THE HOMOGENEITY OF THE EXTINCTION LAW IN OUR GALAXY

  • Bondar, A.;Galazutdinov, G.;Patriarchi, P.;Krelowski, J.
    • Journal of The Korean Astronomical Society
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    • v.39 no.3
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    • pp.73-80
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    • 2006
  • We analyze the extinction law towards several B1V stars-members of our Galaxy, searching for possible discrepancies from the galactic average extinction curve. Our photometric data allow to build extinction curves in a very broad range: from extreme UV till infrared. Two-colour diagrams, based on the collected photometric data from the ANS UV satellite, published UBV measurements and on the infrared 2MASS data of the selected stars, are constructed. Slopes of the fitted straight lines are used to build the average extinction curve and to search for discrepant objects. The selected stars have also been observed spectroscopically from the Terskol and ESO Observatories; these spectra allow to check their Sp/L's. The spectra of only about 30% of the initially selected objects resemble closely that of HD144470, considered as the standard of B1 V type. Other spectra either show some emission features or belong clearly to another spectral types. They are not used to build the extinction curve. Two-colour diagrams, constructed for the selected B1 V stars, showing no emission stellar features, prove that the interstellar extinction law is homogeneous in the Galaxy. Both the shape of the curve and the total-to-selective extinction ratio do not differ from the galactic average and the canonical value(3.1) respectively. The circumstellar emissions usually cause some discrepancies from the average interstellar extinction law; the discrepancies observed in the extraterrestrial ultraviolet, usually follow some misclassifications.

Optical Properties of (V, Pr)-doped ZrSiO4 Green Pigments (바나듐과 프라세오디뮴을 사용한 지르콘녹색안료의 광학적 특성)

  • Pyon, Kyu-Ri;Lee, Byung-Ha
    • Journal of the Korean Ceramic Society
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    • v.47 no.3
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    • pp.249-255
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    • 2010
  • To investigate optical properties of (V, Pr)-doped $ZrSiO_4$ green pigments, samples were prepared by the ceramic method using NaF and NaCl as mineralizers. They were characterized by X-ray diffraction, UV-Vis spectroscopy and Raman spectroscopy. The changes of color in the samples during heating and effect of mineralizers were studied in terms of valence of the vanadium and praseodymium in the zircon matrix. (V, Pr)-doped $ZrSiO_4$ pigments give rise to green coloration in $800^{\circ}C$. The oxidation state of V and Pr ions of pigments in the glazed samples were confirmed by UV-Vis absorption spectra. This absorption spectra showed three typical bands of trivalent Pr at the 445, 480~490, 592 nm due to f-f transitions and two broad bands of 302~380, 400~500 nm due to f-d transitions of tetravalent Pr. According to the increasing amounts of $Pr_6O_{11}$, the two broad bands showed decreasing intensity at 290, 640 nm due to d-d transitions of tetravalent V.

Surface Plasmon Resonances of Metal Colloidal Particles Synthesized by a Photo-Chemical Process (광화학적 방법을 이용한 금속입자의 합성과 광학적 특성 연구)

  • Ko, Min-Jin;Plawsky, Joel
    • Journal of the Korean Chemical Society
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    • v.43 no.1
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    • pp.1-7
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    • 1999
  • Metal colloidal particles have been prepared by a photo-chemical process in an aqueous solution containing semiconductor nanocrystallites. Metal colloidal particles produced in CdS and AgBr exhibit different absorption spectra. Au particles produced in solution with CdS show typical Au plasmon resonance absorption spectra. On the other hand Ag particles in solution with AgBr shows surface plasmon resonance absorption spectra which are red-shifted, as compared to that of a dispersion of homogeneous Ag colloidal particles in the same host. The extent of red-shift depends on the UV illumination time. This phenomenon is interpreted within the context of effective medium theory for small volume fractions. From the theory, a metal coated particle predicts Ag plasmon resonance, red shifted with respect to 400 nm that would be associated with a silver particle in solution. The absorption peak position is very sensitive to the coating thickness.

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Synthesis and Light-emitting Properties of Poly (fluorene) Copolymers Containing EDOT Comonomer

  • Hwang, Do-Hoon;Park, Moo-Jin;Lee, Ji-Hoon
    • Journal of Information Display
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    • v.5 no.4
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    • pp.12-17
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    • 2004
  • A series of statistical random copolymers of dioctylfluorene (DOF) and 3,4-ethylenedioxythiophene (EDOT) were synthesized by Ni (0) mediated polymerization and their light-emitting properties were compared with poly (9,9-di-n-octylfluorene) (PDOF). The synthesized polymers were characterized using UV-vis spectroscopy, TGA, photoluminescence (PL) & electroluminescence (EL) spectroscopy and by conducting molecular weight studies. The resulting polymers were found to be thermally stable and readily soluble in organic solvents. The UV-visible absorption and PL emission spectra of the copolymers were gradually red-shifted as the fraction of EDOT in copolymers increased. Light-emitting devices were fabricated in an ITO (indium-tin oxide)/PEDOT/polymer/Ca/Al configuration. Interestingly, the EL spectra of these devices were similar to the PL spectra of the corresponding polymer film. However, the EL devices constructed from the copolymer showed more than 10 times higher efficiency level than the devices constructed from the PDOF homopolymer. This higher efficiency is possibly the result of better charge carrier balance in the copolymer systems due to the lower HOMO levels of the copolymers in comparison to that of PDOF homopolymer.

Synthesis of Praseodymium-Doped TiO2 Nanocatalysts by Sol-Microwave and Their Photocatalytic Activity Study

  • Huang, Fengping;Wang, Shuai;Zhang, Shuang;Fan, Yingge;Li, Chunxue;Wang, Chuang;Liu, Chun
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2512-2518
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    • 2014
  • The praseodymium-doped $TiO_2$ photocatalyst samples, which could degrade methyl orange under UV irradiation, were prepared by sol-microwave method for improving the photocatalytic activity of $TiO_2$. The resulting materials were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra, Fourier transform infrared spectra (FTIR) and Ultraviolet-visible diffuse reflectance spectra (UV-vis DRS). It was found Pr doping retarded the growth of crystalline size and the phase transformation from anatase to rutile, and narrowed the band gap energy. Praseodymium doping brought about remarkable improvement in the photoactivity. The optimal dopant amount of Pr was 2% by molar of cement and the calcination temperature was $500^{\circ}C$ for the best photocatalytic activity. The improvement of photocatalytic activity was ascribed to the occurrence of lattice distortion and the effective containment of the recombination of the electron-hole by $Pr^{3+}$.