Browsing by Author "Arda, Ertan"
Now showing items 1-7 of 7
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A comparison of fluorescence and UV-visible spectrometry techniques for thermal phase transitions of agarose gels
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Publisher and Date:(Springer, 2015)In this study thermoreversible phase transitions of high (HMP) and low (LMP) melting point agarose gels were investigated by using the UV-vis and fluorescence spectroscopy techniques. Pyranine was added to the aqueous solution of agarose as a fluorescence-probe. Transmitted light (I (tr)) and fluorescence emission (I (fl)) intensities from the gel samples with different agarose concentrations were monitored during the heating (gel-sol) and cooling (sol-gel) processes. For the both techniques gel-sol ...
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Effects of GNP addition on optical properties and band gap energies of PMMA films
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Publisher and Date:(Wiley, 2019)In this study the effects of graphene nanoplatelet (GNP) doping on the optical parameters (absorption coefficient alpha and extinction coefficient k) and the optical transition energies (optical band gap and Urbach energies) of poly(methyl methacrylate)/graphene nanoplatelet (PMMA/GNP) composite films were studied. PMMA/GNP composite films with various GNP mass fractions were prepared by spin coating technique. The absorbance (A) changes of the prepared composites were measured by using UV-Vis ...
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Electrical and optical percolations in PMMA/GNP composite films
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Publisher and Date:(Taylor & Francis Ltd, 2018)Effects of graphene nanoplatelet (GNP) addition on the electrical conductivity and optical absorbance of poly(methyl methacrylate)/graphene nanoplatelet (PMMA/GNP) composite films were studied. Optical absorbance and two point probe resistivity techniques were used to determine the variations of the optical and electrical properties of the composites respectively. Absorbance intensity A and surface resistivity R-s of the composite films were monitored as a function of GNP mass fraction (M) at room ...
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Electrical and optical percolations of polystyrene latex-multiwalled carbon nanotube composites
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Publisher and Date:(Academic Press Inc Elsevier Science, 2010)Electrical conductivity and optical transmittance properties of polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composite films were investigated. Composite films were prepared by mixing of various mass fractions of MWCNT in PS-water dispersions. After water evaporates powder composite films were annealed at 175 degrees C above the glass transition of PS for 20 min. Photon transmission and two point probe resistivity techniques were employed to determine the variations of the optical and the ...
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Electrical optical and fluorescence percolations in P(VAc-co-BuA)/MWCNT composite films
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Publisher and Date:(Taylor & Francis Ltd, 2013)Effects of multiwall carbon nanotube (MWCNT) addition on the electrical conductivities optical transparencies and fluorescence emissions of poly(vinyl acetate-co-butyl acrylate) (P(VAc-co-BuA))/MWCNT composite films were studied. Optical transmission fluorescence emission and two point probe resistivity techniques were used to determine the variations of the optical fluorescence and electrical properties of the composites respectively. Transmitted photon intensity (I-tr) fluorescence emission ...
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Fractal Dimensions of kappa-Carrageenan Gels during Gelation and Swelling
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Publisher and Date:(Taylor & Francis Inc, 2018)A photon scattering technique for research on the sol-gel and gel-sol transitions in kappa-carrageenan-water systems with various carrageenan contents (CC) was utilized for characterizing the fractal dimensions during gelation and swelling. It was observed that the scattered photon intensity I-sc increased at all temperatures with an increase in the CC when I-sc was monitored against temperature. Additionally the sol-gel transition temperatures were found to be much lower than the gel-sol transition ...
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Thermal Phase Transitions of Agarose in Various Compositions: A Fluorescence Study
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Publisher and Date:(Springer/Plenum Publishers, 2011)The effect of agarose content on thermal phase transitions of the agarose gels was investigated by using Steady State Fluorescence (SSF) method. Scattered light I(sc) and fluorescence intensity I(fl) were monitored against temperature during heating and cooling processes to investigate phase transitions. Two regions were observed during the heating and cooling processes. At the high temperature region double helix to coil (h-c) transition took place. However during the cooling process coil to ...
