Navegação Ciências Exatas e da Terra por Assunto "Difração de raios X"
Resultados 1-20 de 40
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Composition, atomic transport, and chemical stability of ZrAl/sub x/O/sub y/ ultrathin films deposited on Si(001)
(2001) [Artigo de periódico]The stability of a ZrAlxOy film sputtered on Si upon thermal annealing in vacuum or in O2 was investigated. X-ray diffraction indicated that the as-deposited film was amorphous and remained so after annealing. Rutherford ... -
A dispenser–reactor apparatus applied for in situ XAS monitoring of Pt nanoparticle formation
(2015) [Artigo de periódico]In situ time-resolved X-ray absorption spectroscopy (XAS) measurements collected at the Pt L3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser–reactor ... -
Environment of hafnium and silicon in Hf-based dielectric films : an atomistic study by x-ray absorption spectroscopy and x-ray diffraction
(2005) [Artigo de periódico]The atomic structure of HfSiO and HfSiON was investigated before and after thermal annealing using x-ray diffraction and x-ray absorption spectroscopy. In HfSiO, the Hf atoms are arranged in a monoclinic HfO2 structure ... -
Estudo da influência dos padrões de emissão das espécies do plasma de carbonitretação nas propriedades superficiais de TiCN
(2015) [Artigo de periódico]As intensidades de emissão das espécies N2 +, H, C, NH, N2, Ar e CN do plasma de carbonitretação (usando os gases Ar+N2+CH4) foram medidas por espectroscopia de emissão óptica (OES) em pressão e temperatura constantes ... -
Ferromagnetic nanoclusters formed by Mn implantation in GaAs
(2005) [Artigo de periódico]Ferromagnetic clusters were incorporated into GaAs samples by Mn implantation and subsequent annealing. The composition and structural properties of the Mn-based nanoclusters formed at the surface and buried into the GaAs ... -
First-principles calculation of the structure and elastic properties of a 3D-polymerized fullerite
(2002) [Artigo de periódico]In this paper we present results obtained from first-principles calculations concerning the crystal structure and elastic properties of a three-dimensional-polymerized fullerite. The orthorhombic structure we studied was ... -
Hardness evaluation, stoichiometry and grain size of titanium nitride obtained with plasma nitriding on Ti-6AI-4V samples
(2010) [Artigo de periódico]Titanium nitride films were formed on the surface of Ti-6Al-4V discs by plasma nitriding (glow discharge) in different N2:H2 atmospheres at several substrate temperatures. In this study the influence of the process parameters ... -
Integrity of hafnium silicate/silicon dioxide ultrathin films on Si
(2002) [Artigo de periódico]Rapid thermal annealing at 1000 °C of (HfO2)12x(SiO2)x pseudobinary alloy films deposited on Si were performed in N2 or O2 atmospheres. The effects on the atomic transport, structure, and composition were investigated using ... -
Ion implantation in β-Ga2O3 : Physics and technology
(2021) [Artigo de periódico]Gallium oxide, and in particular its thermodynamically stable β-Ga2O3 phase, is within the most exciting materials in research and technology nowadays due to its unique properties. The very high breakdown electric field ... -
Ion irradiation-induced foams in antimonide binary alloys : a combination of small energy bandgap with giant surface-to-bulk ratio
(2020) [Artigo de periódico]This is a short review about the ion irradiation-induced foams in antimonide films. III–V semiconductors like InSb and GaSb can be transformed into solid foams with nanometric dimensions upon irradiation with swift heavy ... -
Lattice strain distribution resolved by X-ray Braggsurface diffraction in an Si matrix distorted by embedded FeSi2 nanoparticles
(2013) [Artigo de periódico]Out-of-plane and primarily in-plane lattice strain distributions, along the two perpendicular crystallographic directions on the subsurface of a silicon layer with embedded FeSi2 nanoparticles, were analyzed and resolved ... -
Magnetic and structural properties of Fe-implanted cubic GaN
(2016) [Artigo de periódico]In this article, we report on structural and magnetic properties of cubic GaN epitaxial layers implanted with Fe ions and subsequently subjected to thermal annealing. The epitaxial quality of the layers was studied by X-ray ... -
Mechanical strain and damage in Si implanted with O and N ions at elevated temperatures : evidence of ion beam induced annealing
(2001) [Artigo de periódico]The accumulation of damage and the development of mechanical strain in crystalline Si (c-Si) by O and N ion implantation to doses up to 431017 cm-² at elevated temperatures have been studied using Rutherford backscattering ... -
Mineralogical of a highly-weathered soil by the Rietveld Method
(2010) [Artigo de periódico]A caracterização mineralógica por meio da quantificação dos minerais presentes em solos brasileiros por difração de raios X usando o Método de Rietveld é, ainda, pouco comum. Neste trabalho foi realizada a quantificação ... -
Phase evolution and magnetic properties of a high-energy ball-milled hematite-alumina system
(2004) [Artigo de periódico] -
Potential control of oxygen non-stoichiometry in cerium oxide and phase transition away from equilibrium
(2020) [Artigo de periódico]Cerium oxide (ceria, CeO2) is a technologically important material for energy conversion applications. Its activities strongly depend on redox states and oxygen vacancy concentration. Understanding the functionality of ... -
Pressure-induced phase transitions and volume changes in Hf02 up to Gpa
(1993) [Artigo de periódico]The phase transformations and pressure-volume dependence of Hf02 have been investigated at room temperature by angle-dispersive powder x-ray diffraction under high pressure to 50 GPa in a diamond anvil cell. The phase ... -
Pressure-induced structural phase transitions in zirconia under high pressure
(1993) [Artigo de periódico]Angular-dispersive x-ray in situ powder-diffraction experiments have been performed on pure zirconia, Zr02, at room temperature under high pressure up to 50 GPa. Under increasing pressure four phases were successively ... -
Pressure induced water insertion in the defect pyrochlore nh/sub 4/nbwo/sub 6/
(1997) [Artigo de periódico]A sudden and reversible increase of about 5% in the unit cell volume of ammonium tungstoniobate at pressures around 2.5 GPa was observed with pressure transmitting media containing water. This behavior was attributed to ... -
Quantificação por DRX dos componentes carbonosos presentes no pó de balão do alto-forno
(2011) [Artigo de periódico]A difração de raios X (DRX) é uma técnica padrão para caracterizar a estrutura cristalina dos materiais. Ela também pode ser utilizada para quantificar o tamanho dos cristalitos (Lc ) dos materiais carbonosos. Este trabalho ...
