Search results for "Gel"
showing 10 items of 3561 documents
Investigation on sol–gel synthesized Ag-doped TiO2 cermet thin films
2005
Abstract Undoped TiO 2 and Ag–TiO 2 (up to 23 at.% Ag) cermet thin films and polycrystalline powders have been prepared by sol–gel process. Their structure, composition, surface morphology and optical properties have been investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and ultraviolet–visible spectroscopy (UV–VIS spectroscopy). It has been observed that while Ag does not form a solid solution with TiO 2 , it promotes the anatase to rutile phase transformation. The transformation temperature decreases from 827 °C for undoped TiO 2 to about 650 °C fo…
Preparation and Characterization of Nanostructured Fe-TiO2 Thin Films Produced by Electrophoretic Deposition
2013
Fe-TiO2 thin films have been produced by a sol-electrophoretic deposition method on metallic Ti foil substrates. X-ray diffractograms and Raman spectra confirms the anatase structure of deposited and annealed Fe-TiO2 films. Obtained Fe-TiO2 thin films demonstrate photoactivity under visible light radiation due to the doping with Fe3+ ions. Open circuit potential results shows that increase of the film thickness and surface area improves the photoactivity of Fe-TiO2.
Photocatalytic thin films of TiO2 formed by a sol-gel process using titanium tetraisopropoxide as the precursor
2008
Abstract Thin TiO 2 films were prepared with the dip-coating technique by using sols deriving from titanium tetraisopropoxide. TiO 2 films were formed on glass substrates previously covered by a SiO 2 layer obtained from a tetraethylortosilicate sol. The films, after a thermal treatment at 673 K, mainly consisted of TiO 2 anatase. The samples were characterised by X-ray diffraction, UV–Vis spectroscopy, scanning electron microscopy and atomic force microscopy. The photoactivity of the various films was tested by using as probe reaction the photo-oxidation of 2-propanol in gas-solid regime. The photoreactivity results indicated that the TiO 2 films were efficient for degrading 2-propanol und…
Phase formation in mixed TiO2-ZrO2 oxides prepared by sol-gel method
2011
Pure titania, zirconia, and mixed oxides (3—37 mol.% of ZrO2) are prepared using the sol-gel method and calcined at different temperatures. The calcined samples are characterized by Raman spectroscopy, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption porosimetry. Measurements reveal a thermal stability of the titania anatase phase that slightly increases in the presence of 3—13 mol.% of zirconia. Practically, the titania anatase-rutile phase transformation is hindered during the temperature increase above 700 C. The mixed oxide with 37 mol.% of ZrO2 treated at 550 C shows a new single amorphous phase with a surface area of the…
On the topography of Herbst's and Grandry's corpuscles in the adult and embryonic duck-bill
1932
Izvilkums no: Acta Zoologica, Bd. 12, 1931.
Zur Topographie der Herbst'schen und Grandry'schen Körperchen im adulten und embryonalen Entenschnabel [Herbsta un Grandry ķermenīšu topogrāfija piea…
1931
Teksts vācu valodā, kopsavilkums latviešu valodā.
THE DIASCIA FLOWER AND ITS BEE - AN OIL-BASED SYMBIOSIS IN SOUTHERN AFRICA
1984
As has been formerly shown, the double-spurred flowers of the South African genus Diascia (Scrophulariaceae) produce fatty oil as a primary attractant. Their oil-collecting pollinators have so far remained unknown. It is concluded from the morphology and from direct evidence of flower visitation that the recently established Melittid genus Rediviva represents the co-evolved pollinator group of these plants, at the same time demonstrating the presence of “manual” oil collectors in Southern Africa. The bees must introduce their especially equipped forelegs into the paired spurs of Diascia for harvesting the oil, thereby pollinating the flower. In the described case, a new species, Rediviva em…
“Facts Are Grasped by Us in Pictures (PT, 2.1). Remarks on Pictures and Facts in Wittgenstein’s Tractatus
2023
This paper proposes a (re)reading of the famous section in the Tractatus Logico-philosophicus, 2.1: “We picture facts to ourselves” and its relation to the similar section in the Prototractatus, 2.1: “Facts are grasped by us in images”. We reject the dominant solution that interprets the relation between facts and images as an isomorphic relation and propose that instead it is an internal relation: there are no facts that are not perceived through images. In other words: For us, linguistic animals, there is no world independent of language.
Lanza Damiani Angelina
2010
La voce illustra la vita e l'opera della scrittrice rosminiana Angelina Lanza (1879-1936)
Il mangiare e il bere come figure rivelative dell'esistenza umana / Eating and Drinking as "disclosing" Figures of human Existence
2015
The Author offers an anthropological and philosophical reflexion about same main human activities, such as eating and drinking, to show how they disclose a deep symbolic meaning, essential to the ultimate fulfillment of our life