El SAYED YOUSEF
Articles written in Bulletin of Materials Science
Volume 35 Issue 6 November 2012 pp 961-967
Glass samples have been synthesized in quaternary system based on TeO2–oxide within composition, 85TeO2–5Nb2O5–5ZnO–5Ag2O, 68TeO2–5Nb2O5–20ZnO–7Na2O and [(75−𝑥)TeO2–5Nb2O5–20ZnO–𝑥PbO, 𝑥 = 7, 18 mol%]. Structural characterization of the glasses was studied with respect to their thermal stability, refractive indices, third order nonlinear optical susceptibility, IR spectra and Vickers hardness. For four different prepared glasses, density in the range from 5.3744 to 6.0731 g.cm-1, the glass transition temperature (𝑇g) in the range from 326 to 350 °C and refractive indices, 𝑛, in the range from 2.1273 to 2.2123 at 435 nm and Vickers hardness, 𝐻v, in the range from 2.91 to 3.44 GPa were determined. The value of third order nonlinear optical susceptibilities |𝜒(3)| ≈ 17.9 .10-13 esu of glass within composition, 68TeO2–5Nb2O5–20ZnO–7PbO, was measured by using degenerate four-wave mixing (DFWM).
Volume 40 Issue 3 June 2017 pp 555-560
Quaternary tellurite glasses with composition 75TeO$_2$–5WO$_3$–15Nb$_2$O$_5$–5M$_x$O$_y$ in mol%, where M$_x$O$_y$ =(Na$_2$O, Ag$_2$O, ZnO, MgO, CuO, NiO, TiO$_2$, MnO$_2$), were prepared by the normal melt-quenching method. The ultrasonic velocities (longitudinal and shear) were measured in these glasses using the pulse-echo technique at room temperature. Their elastic moduli, microhardness and Debye temperature were calculated and discussed in terms of the modifier’s ionicity and quantitatively in terms of number of bonds per unit volume and the cross-link density. In this study, the values of ultrasonic velocities, elastic moduli, Debye temperature and microhardness were found to be strongly dependent on three factors, namely: (i) modifier’s ionicity; (ii) trigonal pyramid (TeO$_3$)/trigonal bipyramid (TeO$_4$) ratio; and (iii) glass transition temperature $T_g$. We used the Makishima and Mackenzie’s model to calculate the theoretical elastic moduli and to indicatethat the experimental values were in good agreement with the theoretical values.
Volume 45, 2022
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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