Sağlık Hizmetleri Meslek Yüksekokulu / Vocational School of Health Services
Permanent URI for this collectionhttps://hdl.handle.net/11727/3080
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Item Landau mean-field model with the cubic term for the alpha-beta transition in quartz(2020) Ates, S.; Yurtseven, H.Thermodynamic quantities are calculated as a function of temperature by using Landau mean-field model for the alpha-beta transition in quartz. By expanding the Gibbs free energy in terms of the order parameter (Q) with the cubic term (Q(3)), the temperature dependence of the relevant thermodynamic quantities are predicted using the heat capacity (C-P), which is fitted to the experimental data from the literature for the alpha-beta transition in quartz. Our results indicate that the Landau mean-field model is adequate to describe the first-order alpha-beta transition in quartz.Item Resonant frequency shifts related to the elastic constants near the alpha-beta transition in quartz(2019) Yurtseven, H.; Ates, S.The resonant frequency shifts of vibrational modes are related to the elastic constants at various temperatures for the alpha-beta transition in quartz (T-c = 573.0 degrees C for alpha-quartz and 574.3 degrees C for beta-quartz). This correlation is constructed on the basis of the spectroscopic modifications of the Pippard relations near the alpha-beta transition in quartz by using the observed data from the literature. Our results indicate that the elastic properties can be described from the spectroscopic parameters (frequency shifts) as we have studied here for the alpha-beta transition in quartz. Using those relations, elastic constants can also be obtained from the frequency shifts near the phase transitions of various crystalline systems. (C) 2018 Elsevier B.V. All rights reserved.