Makale 2010-2019 yılları

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https://kurumsalarsiv.tenmak.gov.tr/handle/20.500.12878/270

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Browsing Makale 2010-2019 yılları by Subject "Annealing"

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    ESR and TL studies of irradiated Anatolian laurel leaf (Laurus nobilis L.)
    (Taylor and Francis Ltd., 2012) Tepe Çam, Semra; Aydaş, Canan; Engin, Birol; Yüce, Ülkü Rabia; Aydın, Talat; TAEK-SANAEM
    Laurel leaf (Laurus nobilis L.) samples originated from Turkey were analyzed by Electron Spin Resonance (ESR) and Thermoluminescence (TL) techniques before and after gamma irradiation. Unirradiated (control) loreal leaf samples exhibit a weak ESR singlet centered at g = 2.0020. Besides this central signal, two weak satellite signals situated about 3 mT left and right to it in radiation-induced spectra. The dose-response curve of the radiation-induced ESR signal at g = 2.0187 (the left satellite signal) was found to be described well by a power function.Variation of the left satellite ESR signal intensity of irradiated samples at room temperature with time in a long-term showed that cellulosic free radicals responsible from the ESR spectrum of loreal leaves were not stable but detectable still after 100 days. Annealing studies at four different temperatures were used to determine the kinetic behaviour and activation energy of the radiation-induced cellulosic free radicals responsible from the left satellite signal (g = 2.0187) in laurel leaves. TL measurements of the polymineral dust isolated from the laurel leaf samples allowed distinguishing between irradiated and unirradiated samples.
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    Identification of irradiated sage tea (Salvia officinalis L.) by ESR spectroscopy
    (Elsevier B.V., 2010-04) Tepe Çam, Semra; Engin, Birol; TAEK-SANAEM
    The use of electron spin resonance (ESR) spectroscopy to accurately distinguish irradiated from unirradiated sage tea was examined. Before irradiation, sage tea samples exhibit one asymmetric singlet ESR signal centered at g=2.0037. Beside this central signal, two weak satellite signals situated about 3 mT left and right to it in radiation-induced spectra. Irradiation with increasing doses caused a significant increase in radiation-induced ESR signal intensity at g=2.0265 (the left satellite signal) and this increase was found to be explained by a polynomial varying function. The stability of that radiation-induced ESR signal at room temperature was studied over a storage period of 9 months. Also, the kinetic of signal at g = 2.0265 was studied in detail over a temperature range of 313-353 K by annealing samples at different temperature for various times.