Search results for "scanning electron"
showing 10 items of 667 documents
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…
High photodegradation and antibacterial activity of BN–Ag/TiO 2 composite nanofibers under visible light
2018
To develop material with good photocatalytic properties for organic compound degradation and bacterial removal, we produced Ag/TiO2 and BN–Ag/TiO2 composite nanofibers that included controlled amounts of boron nitride (BN) nanosheets and silver (Ag). After annealing at 500 °C under air, we used scanning electron microscopy, transmission electron microscopy, Brunauer–Emmet–Teller analysis, X-ray diffraction, energy-dispersive X-ray spectroscopy, Raman spectroscopy, UV-visible reflectance spectroscopy and room temperature photoluminescence to investigate the morphological, structural and optical properties of all samples. The photocatalytic tests using methylene blue under visible light, in r…
New hydrogel matrices based on chemical crosslinked α,β -polyas parthydrazide: Synthesis, characterization and in vivo biocompatibility studies
1996
New swellable micromatrices of α,β-polyasparthydrazide (PAHy) crosslinked with glutaraldehyde were prepared. The effect of crosslinking agent concentration was evaluated. In particular, crosslinking density affected aqueous dynamic swelling and glass-transition temperature of the material. The structure of prepared networks was also studied by scanning electron microscopy and X-ray analysis. Finally, biocompatibility of PAHy derivatives was investigated in vivo by subcutaneous implantation and in oral administration to laboratory animals.
Cation and anion electrochemically assisted solid-state transformations of malachite green
2020
[EN] The possibility of the electrochemical promotion of different solid-to-solid transformations including the performance of successive cation and anion insertion processes has been tested using malachite green, a triphenylmethane dye, in contact with aqueous NaCl electrolyte. Electrochemical data using the voltammetry of microparticles methodology reveal significant differences with the solution phase electrochemistry of the dye. Voltammetric data, combined with atomic force microscopy, focusing ion beam-field emission scanning electron microscopy, and high-resolution field emission scanning electron microscopy permit characterization of the oxidative dissolution, oxidation with anion in…
Composite Thin Film by Hydrogen-Bonding Assembly of Polymer Brush and Poly(vinylpyrrolidone)
2005
Based on hydrogen-bonding layer-by-layer (LBL) assembly in aqueous solution, poly(vinylpyrrolidone) (PVPON) and a spherical polymer brush with a poly(methylsilsesquioxane) (PSQ) core and poly(acrylic acid) (PAA) hair chains were used to fabricate composite multilayer thin films. Hydrogen bonding as the driving force was confirmed by FT-IR spectrometry. A simple method (Filmetric F20) was introduced to determine the thickness and refractive index of the films. The film thickness was found to be a linear function of the number of bilayers. The average increase in thickness per bilayer is 28.3 nm. The film morphology was characterized with scanning electron microscopy and atomic force microsco…
Synthesis of new molybdenum–tungsten, vanadium–tungsten and vanadium–molybdenum–tungsten oxynitrides from freeze-dried precursors
2004
Abstract Interstitial molybdenum–tungsten, vanadium–tungsten and vanadium–molybdenum–tungsten oxynitrides in the solid solution series Mo1−zWz(OxNy) and V1−zWz(OxNy) (z=0, 0.2, 0.4, 0.5, 0.6, 0.8, 1), and V1−u−zMouWz(OxNy) (u, z=0.2, 0.33, 0.4, 0.6; u+z
V2O5 nanowires with an intrinsic iodination activity leading to the formation of self-assembled melanin-like biopolymers
2011
V2O5 nanowires act as biomimetic catalysts resembling vanadium haloperoxidases (V-HPO). The nanowires display iodinating activity as confirmed by a colorimetric assay using thymol blue (TB), UV/Vis spectrophotometry and mass spectrometry (FD-MS). In the presence of dopamine these nanowires catalyze the fast and efficient synthesis of melanin-like biopolymers under mild conditions (aqueous solution, neutral pH and room temperature). The resulting melanin-like biopolymer obtained by the V2O5 nanowire catalysts was characterized by scanning electron microscopy (SEM), X-ray diffraction, UV-Vis, FT-IR and electric conductivity resembling the natural biopolymer both in its chemical and morphologi…
Consolidation and protection by nanolime: recent advances for the conservation of the graffiti, Carceri dello Steri Palermo and of the 18th century l…
2014
Abstract Nanolime dispersed in 2-propanol was extensively used for the consolidation of wall paintings. The knowledge of the advances of this methodology dealing with all the possible effects associated with the nanolime new material in conservation is fundamental to assess and improve the technique. In this paper, four different dispersions of Ca(OH) 2 nanoparticles were characterised by Small Angle X-rays Scattering technique (SAXS) and Transmission Electron Microscopy (TEM) in order to achieve information on size, shape, polydispersity, agglomeration, and crystal structure (by SAED patterns) of the particles. Once characterised, the dispersions were tested in two different case studies, …
The Electrical Properties of Ba1-ySryZrxTi1-xO3Solid Solution
2011
A lead-free solid solution Ba0.80Sr0.20Ti0.75Zr0.25O3 was prepared by a conventional technology. The structure and morphology of investgated samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The studies of electric conductivity were performed depending on temperature and frequency of electric measuring field. The activation energy was calculated from the Arrhenius plots.
Effect of Zr4+Doping on the Electrical Properties of BaTiO3Ceramics
2011
The BaZrxTi1-xO3 for 0⩽x⩽15 ceramics were prepared by a conventional solid state reaction method and were determined by an X-ray diffraction (XRD) and scanning electron microscopy (SEM) for crystallographic, surface morphological and compositional studies. A single phase with perovskite structure was identified in the samples at room temperature. No significant impurities were detected in an EDS spectrum and the samples are in good stoichiometric ratio. The temperature dependence of electric conductivity was evaluated in the temperature range from 300 to 550 K for a selected frequency by a HP4284 LCR meter. The activation energy was calculated from the Arrhenius plots.