المؤلفون: Murata, T.¹ (AUTHOR), Nakane, S.¹ (AUTHOR), Yamazaki, H.¹ (AUTHOR), Al-Mukadam, R.² (AUTHOR), Deubener, J.^1,2 (AUTHOR) joachim.deubener@tu-clausthal.de

المصدر: Journal of Non-Crystalline Solids. Apr2023, Vol. 605, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *LITHIUM silicates, *LIQUIDUS temperature, *LITHIUM, *HETEROGENOUS nucleation, *THERMODYNAMICS, *RATE of nucleation

مستخلص: • Glasses along the lithium disilicate – lithium metasilicate join were prepared. • Heterogeneous crystal nucleation was studied by HTOM and DSC. • The maximum nucleation rate was highest for a glass containing ∼63 mol% silica. • The first crystallite consisted of intergrown lithium metasilicate and quartz. • Viscosity at the maximum nucleation rate for each melt was almost constant. The heterogeneous crystal nucleation of five glasses along the compositional join between lithium disilicate and lithium metasilicate was studied by differential scanning calorimetry (DSC) and high-temperature optical microscopy (HTOM). In addition to DSC and HTOM, liquidus temperature and viscosity were measured. DSC and HTOM consisted of 147–378 repetitive cooling runs for each melt and method. DSC and HTOM showed that the crystal nucleation rate was highest for a glass of ∼63 mol% silica and that the first crystallite consisted of intergrown lithium metasilicate and quartz. In the case of DSC, primary crystallization of lithium disilicate was additionally observed, which was treated as an oxygen-related artifact. The viscosity at the maximum nucleation rate was almost constant for each melt, while the liquidus temperature resulting from the linear extrapolation of the DSC-endotherm for a heating rate of 0 K min−1 was 20–30 K higher than that calculated from thermodynamic properties. [ABSTRACT FROM AUTHOR]

المؤلفون: Murata, T.¹ thmurata@ktmail.ktokai-u.ac.jp, Mouri, T.²

المصدر: Journal of Non-Crystalline Solids. Jul2007, Vol. 353 Issue 24/25, p2403-2407. 5p.

مصطلحات موضوعية: *FLUORESCENCE, *RADIOACTIVITY, *ABSORPTION, *SPECTRUM analysis

مستخلص: Abstract: Absorption and fluorescence spectra of Bi ions in multi-component oxide glasses melted in air were measured. Absorption bands in the range of 400–1000nm and fluorescence bands at round 1210nm were only detected in the silicate, borosilicate, borate, and germanate glasses with or without a small amount of alkali or alkaline-earth oxides. The relative IR fluorescence intensity increased with decreasing basicity of matrix glasses and with adding the Al2O3. The compositional dependence of the relative IR fluorescence intensity and the IR fluorescence mechanism are discussed in terms of redox reaction and energy diagram of bismuth-related species in oxide glasses. [Copyright &y& Elsevier]

المؤلفون: Murata, T.¹ murata@asem.kyushu-u.ac.jp, Sato, M.², Yoshida, H.³, Morinaga, K.¹

المصدر: Journal of Non-Crystalline Solids. Feb2005, Vol. 351 Issue 4, p312-316. 5p.

مصطلحات موضوعية: *FLUORESCENCE, *SPECTRUM analysis, *SOLUTION (Chemistry), *RADIOACTIVITY

مستخلص: Abstract: Fluorescence spectra of Ce3+ ions in silicate, borate, and phosphate glasses melted in Ar were measured. The relative fluorescence intensity of Ce3+ in the ultraviolet region increased in the order of R=Ba, Ca, Sr, and Mg in the 20Li2O–20RO–60SiO2 glass samples and with decreasing BaO content in the BaO–B2O3 glass samples, respectively. In contrast, the relative fluorescence intensity of Ce3+ did not change with varying the glass composition in phosphate glass samples. The compositional dependence of the relative fluorescence intensity of Ce3+ is discussed in terms of redox reaction of Ce3+–Ce4+ in oxide glasses. [Copyright &y& Elsevier]

المؤلفون: Sakaguchi, S., Todoroki, S., Murata, T.

المصدر: Journal of Non-Crystalline Solids; 1997, Vol. 220 Issue: 2 p178-186, 9p

المؤلفون: Murata, T., Torisaka, M., Takebe, H., Morinaga, K.

المصدر: Journal of Non-Crystalline Solids; 1997, Vol. 220 Issue: 2 p139-146, 8p