• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.137-140
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• 2006

This paper describes a technique combining chemometrics with UV spectroscopy for the determination of the concentra tions of two tissue additives (i.e., wet strength and softening agents) in a cellulose fiber containing solution. In single as ent solutions, the concentration of the additive can be measured by UV spectroscopy at the wavelength where the species having absorption. For a binary (i.e., containing two additives) solution system, the spectral characterization is very complicated. However, if aided by a chemometrical calibration technique, each additive in the binary solution can be quantified simultaneously. The present method is very rapid and simple, it can easily perform a continuous measurement in the changes in the additives' concentration after fiber addition, and therefore this becomes a valuable tool for the adsorption kinetics study of chemical additives onto the cellulose fibers. The time-dependent adsorption behaviors of the wet-strength, softening agent, and their both on fiber were also presented.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.243-251
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• 2008

Analyses of UV-Vis spectrum and reflectance are useful tools to identify pearls of which color was naturally made or chemically changed. Contents of some trace elements of pearls by using ED-XRF may give us the information that the pearls were originated from marine shells or freshwater shells, and may give us whether the pearls were chemically treated or not. Three types of chemically untreated pearls, freshwater cultured, Akoya cultured and Tahitian cultured, were treated with silver nitrate. UV-Vis absorbance spectrum of Ag was changed after treatment, and reflectance of pearls was decreased. Absorbance of natural black colored Tahitian cultured pearls at 400, 500 and 700 nm was observed. Natural black colored freshwater cultured pearls showed two characteristic absorption patterns in UV-Vis spectra at 380-400, 480-500 nm. Unlike naturally black colored Tahitian cultured pearls, the absorption spectrum at 700 nm could not be found from black freshwater cultured pearls. Manganese was not detected in the pearls from marine shells, and strontium content of the pearls from marine cultured shells was higher than that from freshwater cultured shells. According to ED-XRF analysis, Ag contents of silver nitrate treated pearls increased as more time passed, because silver ion invaded to nacre layer of the pearls. Since Ag content of the black pearls known as untreated ranged under 0.1%, analysis of Ag content may used to distinguish the black pearls are treated or not in marketplace.

• 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.

• Journal of the Korean Ceramic Society
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• v.34 no.9
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• pp.993-1001
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• 1997

The (0.8PPV+0.2DMPPV) copolymer and silica/borosilicate composites were synthesized by sol-gel process. The organic-inorganic hybrid solution was prepared by using of (0.8PPV+0.2DMPPV) copolymer precursor solution as a raw material for organic components and TEOS and TMB for glass components. Then by drying the solution in vacuum at 5$0^{\circ}C$ for 7days and subsequent heat treatment in vacuum at 15$0^{\circ}C$~30$0^{\circ}C$ for 2h~72h with heating rate of 0.2$^{\circ}C$/min and 1.8$^{\circ}C$/min, the organic-inorganic composites were synthesized. Microstructural evolution of the composites was characterized by DSC, IR spectrocopy, UV/VIS spectroscopy, and TEM. Elimination of the polymer precursor and degradation of the polymer were observed by DSC and Si-O and trans C=C absorption peaks were identified by IR spectra. The polymer was found to be successfully incorporated into the glass matrix and it was confirmed by the absorption peaks from the polymer in the UV/VIS spectra and the TEM results. The absorption peak of the composites was found to shift toward short wavelength side compared to that of the pure polymer and the amount of the blue shift increased with increasing the heat treatment temperature and heat treatment time and with decreasing the heating rate.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.39-42
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• 2006

Titania sols or powders were are very promising materials for environment as photocatalyst. The band gap energy of $TiO_2$ has been known to be 2.8 to 3.2 eV. But the measuring system of its band gap is usually depend on absorption properties. Thus, in this study, absorption properties of $TiO_2$ sols prepared by hydrothermal process were researched with the effect of various particle sizes and concentrations. The mean particle size in $TiO_2$ sols increased as 15 nm to 60 nm, absorption graph measured by UV-Vis spectrometer shows to move red-shift. When dilute solution added with $2^n$ in $TiO_2$, the band gap energy increases as linear function.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.479-482
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• 2000

We investigated UV-vis absorbances to observe photoisimerization and effect of temperature using the mixture solution in chloroform and the LB monolayer mixed with DLPE and 8A5H containing azobenzene which shows reversible cis-trans isomerization irradiated by alternate lights. We could find that the absorption spectrum of the mixtures solution and LB monolayer was reversibly induced to photoisomerization irradiated by Uv of both and visible lights, in addition the absorbance by alternate temperatures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.1
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• pp.12-20
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• 2010

Metamictization and color change in zircons from Cambodia and Tanzania were investigated. Elements analysis to detect radioactivity of elements such as U and Th, and spectroscopic analysis using UV-VIS and Fourier transform infrared spectroscopy were performed. According to the UV-VIS spectroscopic analysis, it was perceived that many and high intense absorption peaks appeared in blue and colorless zircons, while less and low intense absorption peaks appeared in uranium contained green and yellow zircons. It was found that those stones have made progress to the metamictization. After heat treatment, we could detect opposite results. As the results of FTIR spectroscopy analysis, in the metamict green and yellow zircon, it is showed that 3-phonon combination mode bands of $[SiO_4]^{4-}$ internal vibration in the region of 3100~3400 $cm^{-1}$ are broad and some of them disappear. However, the disappeared bands are observed again due to restored crystal lattice by the heat treatment. Also, $U^{4+}$ peaks that can detect the uranium content in zircon appears at near 4800 $cm^{-1}$ in the green and yellow samples. From this investigation, we could observe the metamictization effect and color change in uranium-bearing zircon by heat treatment using spectroscopic analysis.

• Korean Journal of Materials Research
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• v.27 no.9
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• pp.459-465
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• 2017

Nano-sized Zinc selenide (ZnSe) powder was successfully synthesized using Zn and Se precursors in a hydrothermal process. Temperature for the synthesis was varied from $95^{\circ}C$ to $180^{\circ}C$ to evaluate its influence on the microstructural properties of the synthetic particles. ZnSe powder thus fabricated was characterized using various analytical tools such as SEM, XRD, TEM and UV-Vis methods. Two types of ZnSe particles, that is, the precipitated particle and the colloidal particles, were identified in the analysis. The precipitated particles were around 100 nm in average size, whereas the average size of the colloidal particles was around 20 nm. The precipitated particles made at $150^{\circ}C$ and $180^{\circ}C$ were found to be a single phase of ZnSe; however, an inhomogeneous phase was obtained at the lower synthesis temperature of $95^{\circ}C$, suggesting that the temperature for the synthesis should be over $100^{\circ}C$. The precipitated particles were inactive in the UV-Vis absorption investigation, whereas the colloidal particles showed that absorptions occurred at 380 nm in the UV-Vis spectrum.

• 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.