A5022344607- X-ray Diffraction in Crystallography
- Solar and Space Plasma Dynamics
- Advanced ceramic materials synthesis
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Astronomy and Astrophysical Research
- Advanced materials and composites
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Nuclear materials and radiation effects
- Microstructure and Mechanical Properties of Steels
- Historical Astronomy and Related Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Microstructure and mechanical properties
- Astronomical Observations and Instrumentation
- Glass properties and applications
- Impact of Light on Environment and Health
- Catalysis and Oxidation Reactions
- Aluminum Alloys Composites Properties
- Advancements in Solid Oxide Fuel Cells
- Atmospheric Ozone and Climate
- Thermal and Kinetic Analysis
- Chaos control and synchronization
- Experimental and Theoretical Physics Studies
Universidad de Extremadura
2013-2022
A modified application of the variance method, using pseudo-Voigt function as a good approximation to X-ray diffraction profiles, is proposed in order obtain microstructural quantities such mean crystallite size and root-mean-square (r.m.s.) strain. Whereas method its original form applicable only well separated reflections, this technique can be employed cases where there line-profile overlap. Determination r.m.s. strain for several crystallographic directions nanocrystalline cubic sample...
The main properties (integral breadth, FWHM, Fourier transform) of the split Voigt function have been analysed. These are important in study X-ray diffraction peaks. In this way, some lines a sample quartz and zirconia has analysed by using single line methods, describing instrumental-spectral asymmetric peaks means functions.
A worked example of polytypism is presented, aimed at assisting undergraduates in the learning and instructors teaching this topic. In particular, crystallography concept, not necessarily obvious for beginners, illustrated pedagogically using to that end model case prolific silicon carbide (SiC). On basis concepts are easily assimilated by students ( i.e. simple topological constraints) article first presents a unified description phenomenon SiC allows one understand without difficulty...
An analysis of the sunspot observations made by Hevelius during 1642-1645 is presented. These records are only systematic just before Maunder Minimum. We have studied different phenomena meticulously recorded after translating original Latin texts. re-evaluate groups this period and obtain an average value 7% greater than that calculated from his given in current group database. Furthermore, active day fraction obtained work Hevelius' previous to Minimum significantly solar activity level...
This work presents a fast and direct controlled routine for the fabrication of fully dense alumina based on reactive spark plasma sintering (reactive-SPS) boehmite (γ-AlOOH) nano-powders obtained by sol–gel technique. The evolution transition aluminas during has been studied. Some powders were seeded with α-Al2O3 particles prior to gelation. Boehmite exhibited at 1070 °C, enhancing transformation kinetics lowering required temperature more than 100 °C. For comparison, other samples prepared...
An alternative formulation of the variance method for line-broadening analysis polycrystalline materials is presented. It maintains theoretical basis earlier formulations method, but differs in manner calculating coefficients line profiles. In proposed formulation, these are evaluated analytically terms shape parameters Voigt functions fitted to X-ray diffraction data. Explicit expressions thus derived (surface-weighted) crystal sizes and (root-mean-square) lattice microstrains from integral...
Accurate quantitative X‐ray diffraction analysis of SiC‐based ceramics is difficult because the significant overlap Bragg reflections from different SiC polytypes. In this regard, Rietveld method a powerful tool for accurate and precise phase/polytype compositions in these materials. study, we have used two types codes liquid‐phase‐sintered specimen: FULLPROF, which based on classical approach, BGMN, new fundamental parameter approach. both cases, effect texture corrections precision also...
In 1997 the Sun and Earth passed through equatorial plane of Jupiter therefore orbital planes its main satellites. During this period, mutual eclipses occultations occurred were observed. We investigate precision catalogue to produce improved data for development dynamical models. Light curves recorded by observers international campaign PHEMU97 organized Institut de Mécanique Céleste, Paris, France. made 275 observations 148 events from 42 sites. For each observation, information is given...