Browsing by Subject "Energy dispersive X ray spectroscopy"

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    Hydrazine oxidation at gold nanoparticles and poly(bromocresol purple) carbon nanotube modified glassy carbon electrode
    (Elsevier, 2014) Koçak S.; Aslişen B.
    Bromocresol purple monomers were polymerized electrochemically at carbon nanotube modified glassy carbon electrode surface and obtained electrodes were donated as poly(BCP)/CNT/GCE. After electrochemical polymerization, Au nanoparticles were doped on the polymer film carbon nanotube modified glassy carbon electrode surface by electrochemical reduction from their acidic solutions. Modified electrodes are characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical behavior of hydrazine oxidation was investigated at gold nanoparticles modified poly(BCP)/CNT electrodes in pH 10.0 phosphate buffer solution. The obtained results were compared with other modified electrodes. The best catalytic activity was obtained at AuNPs/poly(BCP)/CNT/GCE due to the shift of oxidation peak to more negative values than other electrodes with a higher current value. The peak potential and current oxidation of hydrazine were obtained at AuNPs/poly(BCP)/CNT/GCE (-28 mV, 205 μA) and poly(BCP)/CNT/GCE (427 mV, 80 μA). Under optimal conditions, the calibration curves for hydrazine were obtained over the range of 5.0 × 10-7-1.0 × 10-3 M. The limit of detection for hydrazine was calculated as 1.0 × 10-7 M for AuNPs/poly(BCP)/CNT/GCE. © 2014 Elsevier B.V.
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    Thermoluminescence kinetic parameters of beta irradiated the zinc gallate phosphor using different methods
    (Elsevier Ltd, 2023) Altowyan A.S.; Sonsuz M.; Kaynar Ü.H.; Hakami J.; Ayvacikli M.; Topaksu M.; Can N.
    The ZnGa2O4 phosphor material was synthesised through the gel combustion method, and its structural characteristics were studied via X-ray powder diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The XRD result indicates the generation of ZnGa2O4 in spinal cubic phase with a 25 nm crystalline size. The synthesized phosphor was irradiated using a90Sr/90Y source with a dose range of 0.1 Gy–100 Gy. For measuring thermoluminescence (TL), a linear heating rate of 2 °Cs−1 was applied to the sample in a temperature range of 25 °C–450 °C. The TL experiment revealed two peak maxima located at 180 °C and 304 °C and a shoulder around 70 °C. By preheating at 110 °C, the low temperature peak at 70 °C is removed. Both the depth and frequency factors of electron traps were determined using various heating rates (VHR), Tm-Tstop combined with initial rise (IR), and Computerised Glow Curve Deconvolution (CGCD). In both the Tm-Tstop and CGCD methods, six overlapping glow peaks were detected below the main glow peaks. The calculated activation energy values and peak maximum temperatures agree well with each other. The depths of electron traps calculated by different methods were found to be between 0.4 and 1.4 eV. We observed that both peak maximum temperatures and the area under glow peaks gradually decreased with an increase in the heating rate. Both Peak 1 and Peak 2 show sublinear relationship between 0.1-5Gy and 10–100 Gy. The findings of the present study show that the phosphors can serve as effective TLDs. © 2023 Elsevier Ltd and Techna Group S.r.l.