![]() A dilute solution of uranium nitrate dissolved in water was forced through nanoporous silica gel at fixed and controlled water flow rates. Trace quantities of a uranyl dissolved in water were measured using a simple optical method. Uranyl adsorption kinetics within silica gel: dependence on flow velocity and concentration This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er 3+ to Er 2+ ions. The concentration levels of these point defects are much lower in γ-ray irradiated sol- gel silica glasses. This happens in the sol- gel aluminum- silica glass after an exposure to γ-rays (kGy) and in sol- gel silica glass after an exposure to electrons (MGy). Electron paramagnetic resonance studies reveal the presence of E′ δ point defects. The radiation-induced attenuation of Er 3+ -doped sol- gel silica is found to increase with erbium content. The sol- gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol- gel technique. A possible application of these sol- gel glasses could be their use in harsh radiation environments. The aim of the present paper is to report the effect of radiation on the Er 3+ -doped sol- gel silica glasses. León Pichel, Mónica Ollier, Nadège El Hamzaoui, Hicham Bigot, Laurent Savelii, Inna Bouazaoui, Mohamed Poumellec, Bertrand Lancry, Matthieu Ibarra, Angel Radiation hardening in sol- gel derived Er3+-doped silica glasses Finally, we have determined that the effect of supercritical drying on the fractal nature of condensed silica gels is not appreciable The fractal dimension of the porous silica structures was found to be process dependent. For comparison, we have also generated porous silica glasses by rupturing dense silica and computed their fractal dimension. The self-similarity of aerogel structures was investigated by evaluating their fractal dimension from geometric correlations. Care was taken to reproduce the sol- gel condensation reaction that forms the gel backbone as realistically as possible and to thereby produce credible gel structures. We have used molecular dynamics simulations based on a three-body potential with charge transfer to generate nanoporous silica aerogels. Using x-ray photoelectron spectroscopy, we have shown that with a decrease in the surface water on the film, its hydrophilicity increases logarithmically.įractal dimensions of silica gels generated using reactive molecular dynamics simulations Atomic force microscopic analysis revealed that the silica films prepared with low water had a rough surface (âˆ❃0 nm), while the films prepared with high water had a smoother surface (âˆ❂ nm). Instead, adding water into the sol resulted in silica films with an average water contact angle greater than 60 deg. for a long time (6 months) without any UV irradiation. The average water contact angle of the silica films prepared with low water content and annealed at 300 deg. C and then annealed in a temperature range of 200-500 deg. ![]() The transparent coated films were dried at 100 deg. Two kinds of sol- gel silica thin films were fabricated by dip-coating of glass substrates in two different solutions with low and high water. In this investigation, sol- gel synthesized nanoporous silica thin films, annealed at different temperatures, with long time superhydrophilic property have been studied. Ganjoo, S Azimirad, R Akhavan, O Moshfegh, A Z International Nuclear Information System (INIS) Persistent superhydrophilicity of sol- gel derived nanoporous silica thin films
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