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11.
Nanosized TiO2 particles (nTiO2) are usually coated with an Al(OH)3 layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles
are exposed to UV radiation. Therefore, it is vital to insure the structural stability of these particles in the environment
where the protective layer may be damaged and adverse health and environmental effects can occur. This study utilized X-ray
analysis (SEM–EDS) to provide a qualitative and semi-quantitative assessment of the chemical and physical characteristics
of Al(OH)3-coated original and damaged nTiO2 particles (used in sunscreen lotion formulations) in the presence of both swimming pool and seawater. Also, by utilizing
statistical tools, a distribution of Al/Ti (%) on the particle surface was determined and evaluated. It was found that 45 min
of treatment with swimming pool and seawater significantly induced the redistribution of Al/Ti (%), which changed the surface
characteristics of particles and, therefore, may have induced undesired photo-activity and the consequent formation of free
radicals. 相似文献
12.
Minvydas Ragulskis Loreta Saunoriene Jurate Ragulskiene 《Optics and Lasers in Engineering》2006,44(11):1209-1218
Inverse problem of reconstruction of dynamic displacements from the fringe pattern generated by time average reflection moiré is investigated in this paper. A technique for numerical simulation of time average smoothed reflection moiré fringes is proposed. The smoothing procedure is incorporated into the finite element formulation of the problem. Reconstruction of the field of deflections is illustrated for a centrally clamped disk. Such techniques can be effectively exploited in hybrid numerical–experimental procedures for different objects and grating geometries. 相似文献
13.
Lidia González Jurate Simokaitiene Xavier Ramis Josep Maria Salla Ana Mantecón Angels Serra 《Journal of polymer science. Part A, Polymer chemistry》2008,46(9):3088-3097
A new epoxy resin derived from Meldrum acid (DGMA) was synthesized by a two steps synthetic procedure and structurally characterized by the usual spectroscopic techniques and elemental analysis. Ytterbium and lanthanum triflates were tested as cationic initiators to cure this resin and its mixtures with diglycidylether of bisphenol A (DGEBA) in several proportions. By FTIR‐ATR spectroscopy the evolution of the groups, which participate in the curing was followed. The evolution of the curing and the Tg of the materials were studied by differential scanning calorimetry and the kinetic parameters were calculated applying isoconversional procedures. Ytterbium triflate led to a quicker curing than lanthanum. The thermal stability of the materials obtained was evaluated by thermogravimetry and the higher thermal degradability of the materials containing DGMA was confirmed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3088–3097, 2008 相似文献
14.
Dalia Jonynaite Darius Jasaitis Rimantas Raudonis Algirdas Selskis Remigijus Juskenas Jurate Senvaitiene Aivaras Kareiva 《Central European Journal of Chemistry》2012,10(5):1574-1583
In the present work, the formation of cobalt aluminium spinel (CoAl2O4) as well as novel cobalt neodymium-aluminates with nominal compositions of CoAl1.75Nd0.25O4, CoAl1.5Nd0.5O4 and CoAlNdO4 by an aqueous sol-gel process and the sinterability of the products are investigated. The metal ions, generated by dissolving
starting materials of metals in the diluted acetic acid were complexed by 1,2-ethanediol to obtain the precursors for the
mixed metal ceramics. The phase purity of the synthesized compounds was characterized by powder X-ray diffraction analysis
and infrared spectroscopy. The microstructural evolution and morphological features of the products were studied by scanning
electron microscopy and atomic force microscopy, which together with the optical characterization of these new compounds showed
that the sol-gel-derived materials could be successfully used as effective cobalt-based ceramic pigments.
相似文献
15.
Loreta Saunoriene Kamilija Jablonskaite Jurate Ragulskiene Minvydas Ragulskis 《Entropy (Basel, Switzerland)》2022,24(5)
A computational technique for the determination of optimal hiding conditions of a digital image in a self-organizing pattern is presented in this paper. Three statistical features of the developing pattern (the Wada index based on the weighted and truncated Shannon entropy, the mean of the brightness of the pattern, and the p-value of the Kolmogorov-Smirnov criterion for the normality testing of the distribution function) are used for that purpose. The transition from the small-scale chaos of the initial conditions to the large-scale chaos of the developed pattern is observed during the evolution of the self-organizing system. Computational experiments are performed with the stripe-type patterns, spot-type patterns, and unstable patterns. It appears that optimal image hiding conditions are secured when the Wada index stabilizes after the initial decline, the mean of the brightness of the pattern remains stable before dropping down significantly below the average, and the p-value indicates that the distribution becomes Gaussian. 相似文献