Search results for "GLASS"
showing 10 items of 1153 documents
Физика и химия стеклообразующих систем. Выпуск 6
1979
В сборнике публикуются результаты по исследованию физических свойств и по синтезу оксидных стекол и тонких некристаллических слоев.
Физика и химия стеклообразующих систем. Выпуск 5
1977
В настоящем выпуске публикуются работы в области физики и химии оксидных стеклообразующих систем.
Par aptiekas stikla labvērtības noteikšanu
1933
Kopsavilkums vācu valodā.
Synthesis and characterization of chalcogenide glasses from the system Ga-Ge-Sb-S and preparation of a single-mode fiber at 1.55 μm
2008
International audience; The aim of this work is to study different compositions in the Ga-Ge-Sb-S system for the definition of two compositions compatible with the elaboration of a single-mode fiber at the 1.55 μm telecom wavelength. The variations of the glass transition temperature (Tg), the dilatation coefficient (α) and the refractive index (n) have been studied for two glasses series: GaxGe25−xSb10S65 (series 1), Ga5Ge25−xSb10S60+x (series 2). This study has lead to the choice of the Ga4Ge21Sb10S65 composition as clad glass for the preparation of the single-mode fiber and Ga5Ge20Sb10S65 composition as the core. The discrepancies for the studied parameters between the core and clad comp…
Investigation of water sorption and aluminum releases from high viscosity and resin modified glass ionomer.
2019
Background High viscosity glass ionomer cement (HVGIC) and resin-modified glass ionomer cement (RMGIC) have recently been clinically preferred thanks to their numerous advantages. However, initial moisture contamination has a negative effect on the mechanical and physical properties of these cements. The aim of this study was in vitro of HVGICs and RMGICs, with and without surface protection, on water sorption, solubility and release of aluminum. Material and Methods In this study, as HVGICs; Equia Forte, IonoStar Plus, Riva Self Cure; as RMCIS, Ionolux and Riva Light Cure; and as control, Z250 universal composite was used. Equia coat, Voco varnish and Riva coat were chosen as surface prote…
Water absorption and hydrothermal ageing of epoxy adhesives reinforced with amino-functionalized graphene oxide nanoparticles
2021
Abstract The study is focused on quantitative characterization of water absorption and hydrothermal ageing effects in a room-temperature amine cured epoxy adhesive widely used in automotive, aerospace, construction, and marine industries. Amino-functionalized graphene oxide (mGO) nanoparticles were incorporated into the epoxy (up to 1.72 wt.%) enabled cross-linking reactions and providing high interfacial adhesion, superior reinforcement efficiency and enhanced resistance to hydrothermal ageing of nanocomposites. Anomalous water absorption accompanied by progressive weight loss of samples (down to 7%) is fitted by two-stage models considering additive and coupled contribution from water dif…
OH-related Infrared Absorption Bands in Oxide Glasses
2005
We report the infrared activity, in the spectral region of the OH stretching modes, of different composite silicate glasses whose chemical composition is established by X-ray fluorescence measurements. The analysis of the absorption line profiles is made in terms of different spectral contributions, Gaussian in shape. The comparison with analogous spectra obtained in vitreous silica samples with impurity concentrations < 100 part per million moles is evidence of the effects of the different oxides on the vibrational properties of the OH groups. In particular, for oxide glasses a red shift of the composite band at about 3670 cm(-1), assigned to the OH stretching modes of free Si-OH groups an…
In-situ observation of beta-ray induced UV optical absorption in a-SiO2: radiation darkening and room temperature recovery
2006
International audience; We studied the optical absorption in the 3.0-6.2 eV range induced in bulk amorphous SiO2 by beta-ray irradiation up to similar to 1 MGy at room temperature. The induced absorption was measured in situ both during irradiation and in the post irradiation time. Our data evidence E', center as the main defect induced by irradiation and the partial decay of their absorption band at about 5.8 eV after irradiation. A quantitative analysis of the time evolution of the induced absorption shows that the transmission recovery observed after irradiation is compatible with the reaction of radiation-induced defects with H-related (H-2, H2O) species diffusing in the amorphous matrix
Mechanism of crystallization of fast fired mullite-based glass–ceramic glazes for floor-tiles
2006
Abstract The mechanism of crystallization from a B 2 O 3 -containing glass, with composition based in the CaO–MgO–Al 2 O 3 –SiO 2 system, to a glass–ceramic glaze was studied by different techniques. Glass powder pellets were fast heated, simulating current industrial tile processing methods, at several temperatures from 700 to 1200 °C with a 5 min hold. Microstructural study by field emission scanning electron microscopy revealed that a phase separation phenomenon occurred in the glass, which promoted the onset of mullite crystallization at 900 °C. The amount of mullite in the glass heated between 1100 and 1200 °C was around 20 wt%, as determined by Rietveld refinement. The microstructure …
Effect of boron oxide on the microstructure of mullite-based glass-ceramic glazes for floor-tiles in the CaO–MgO–Al2O3–SiO2 system
2006
Abstract The effect of increasing replacement of Al2O3 by B2O3 in a parent glass on the sintering and further crystallization of mullite was investigated. The composition of the parent glass was chosen in the mullite primary phase field of the CaO–MgO–Al2O3–SiO2 quaternary system. Glass powder pellets were heated under standard (10 °C/min and 2 h of hold time) and fast heatings (25 °C/min and 5 min of hold time) at different temperatures from 700 to 1190 °C. Sintering of B2O3-containing glasses took place in the range between 850 and 1050 °C. X-ray diffraction results showed that mullite formed as unique crystalline phase for glasses containing amounts of B2O3 larger than 6 wt%. For lower a…