• Elastomers and Composites
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• v.50 no.3
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• pp.217-222
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• 2015

Carbon-nickel nanocomposites were prepared by the reaction of fullerene ($C_{60}$) and nickel hydroxide in an electric furnace at $700^{\circ}C$ for 2 h. The hybrid carbon-nickel nanocomposites were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The kinetics and catalytic activity of the carbon-nickel nanocomposites in the reduction of 4-nitrophenol were confirmed by UV-vis spectroscopy.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.334-336
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• 2003

Polyaniline(PANi) composite panicles were synthesized by chemical oxidation polymerization of aniline in presence of Poly-N-Isopropyl acryl amide(PNIPAM). The PANi panicles are formed in the reaction medium deposited onto non-conducting PNIPAM template to produce PANi-coated composite panicles. The formation of composite was confirmed by FT-IR spectroscopy, and UV-VIS spectroscopy, and their morphological structures were examined by scanning electron microscopy(SEM). From the experimental results, it was determined that PANi was successfully coated onto non-conducting PANIPAM.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.611-615
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• 2013

Vanadium oxide ($VO_2$) and tungsten-doped vanadium oxide (W-$VO_2$) powder, well known as thermochromic materials, were prepared from vanadium pentoxide ($V_2O_5$) and oxalic acid dihydrate by hydrothermal and calcination process. The crystal structure and thermochromic property of samples were analyzed using FE-SEM, XRD, XPS, DSC, and UV-Vis-NIR spectroscopy. With increasing the doping amount of W, the phase transition temperature of W-$VO_2$ sample decreased from $70^{\circ}C$ to $42^{\circ}C$. When heating W-$VO_2$ sample above the phase transition temperature, the UV-Vis-NIR spectrum was not changed in the visible range and shifted towards a low transparency in the full name (NIR) region.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.49-49
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• 2009

Nanocomposites of gold nanoparticles and multi-walled carbon nanotubes (MWNTs) were prepared by electrostatic interaction. Gold nanopartic1es were stabilized by polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS) and poly(sodium-4-styrenesulfonate) (PSS) in aqueous medium, and MWNTs were modified by poly(diallyldimethylammonium)chloride (PDDA) in water. The as-perpared Au-MWNT nanocomposites were structurally and electrically characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV/Vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and cyclo voltammetry (CV). UV/Vis spectra of Au-MWNT nanocomposites showed the characteristic surface plasmon bands in the range of ~515nm, depending on the stabilizers. There is only slight change on the band shape with variation of stabilizing agents for gold nanoparticles. Through FE-SEM and TEM images, the distribution of gold, nanoparticles on the sidewalls of MWNTs was deliberately investigated on Au-MWNT nanocomposites treated with different stabilizers. XPS and CV showed redistribution of electron densities and changes in the binding energy states of nanopartic1es in nanocomposite respectively.

• 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.

• BMB Reports
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• v.42 no.4
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• pp.223-226
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• 2009

We measured the pH-induced spectral changes of yeast iso-1-cytochrome c on silver nanoparticle surfaces using surface-enhanced resonance Raman scattering (SERRS) at 457.9 nm. At a pH of ~3, the Met80 ligand in yeast iso-1-cytochrome c is assumed to dissociate, leading to a marked conformational change as evidenced by the vibrational spectral shifts. The Soret band at ~410 nm in the UV-Vis spectrum shifted to ~396 nm at pH~3, indicating a transition from a low spin state to a high spin state from a weak interaction with a water molecule. Thus, SERRS spectroscopy can measure the pH-induced denaturalization of cyt c adsorbed on metal nanoparticle surfaces at a lower concentration with a better sensitivity than ordinary resonance Raman spectroscopy.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.15-21
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• 1988

The Polarographic behavior of 1-(2-thiazolylazo)-2-naphthol (TAN) in acetonitrile solution was studied. From the DC polarograms of TAN in acetonitrile solution, the type of reduction current and the effect of proton donor such as water have been investigated. In order to explain the reduction mechanism, the number of the electrons for each reduction step was measured by controlled potential coulometric technique and the electrolysis products were identified by UV-Vis spectroscopy and IR spectroscopy. The results were shown that the reduction of TAN in acetonitrile solution occurred with four-one electron steps. In addition, each reduction step was considerably reversible and the reduction current was diffusion controlled.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.296-301
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• 1999

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).

• Polymer(Korea)
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• v.28 no.6
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• pp.545-550
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• 2004

The refractive index of thin copolymer film was controlled by photo-degradation of chromophores in the copolymer. FTIR and UV/Vis spectroscopy were employed to elucidate the effect of chemical structure on refractive index changes after photobleaching. The decrease of refractive index of the film by photobleaching can be ascribed to the decrease of polarizability of polymer molecules through breakage of C =C bond in the chromophore. Due to the selective photoreaction of the chromophores which align along the film plane, refractive index of the copolymer film measured in TE mode decreases faster than that in TM mode. Polarized ATR-FTIR spectroscopy was used to verify such a difference in refractive index of the film.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.730-734
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• 1993

The electrochemical reduction behavior or Biliverdin (BV) in N,N-dimethylformamide solvent was studied by DC polarography, cyclic voltammetry and the controlled potential coulometry. The reduced product was indentified by UV-Vis spectroscopy. In DC polarogram, two reduction waves of BV were founded. The half wave potentials of two reduction waves were -0.71 and -0.91 V vs. Ag/Ag$^+$ respectively. The current type of the 1st reduction wave was diffusion-controlled and the 2nd was diffusion current containing a little kinetic current. The 1st electrochemical reduction process was irreversible and BV reduced to Bilirubin.