Method Of Rietveld
Mostrando 25-36 de 90 artigos, teses e dissertações.
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25. Synthesis and Crystal Structure of Three New Quaternary Compounds in the system Cu-Mn-III-Se3 (III = Al, Ga, In)
Chalcogenide alloys CuMnAlSe3, CuMnGaSe3 and CuMnInSe3, new members of the semiconductor system I-II-III-VI3, were synthetized and structurally characterized by the Rietveld method using X-ray powder diffraction data. All compounds crystallize in the tetragonal space group P4 2c (Nº 112) with a CuFeInSe3-type structure.
Mat. Res.. Publicado em: 05/02/2018
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26. Influence of pH in Obtaining Indium Tin Oxide Nanoparticles by Microwave Assisted Solvothermal Method
A systematic study about synthesis of In1-xSnxO2 (ITO) nanostructured crystals by microwave-assisted solvothermal method is reported. Different solutions using InCl3.4H2O and SnCl4.5H2O precursors in ethylene glycol solvent were prepared in distinct pHs (acid and basic ones). The syntheses were performed at 200 ºC using a heating rate of 50 ºC min-1 and so
Mat. Res.. Publicado em: 22/01/2018
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27. Local piezo-response for lead-free Ba0.9Ca0.1Ti0.9Zr0.1O3 electro-ceramic by switching spectroscopy
The purpose of this work is to determine the effective piezoelectric coefficient (d33) and the macro ferroelectric hysteresis behavior for the Ba0.9Ca0.1Ti0.9Zr0.1O3 (BCZT). The sample was prepared by the modified Pechini method and it was sintered at 1250 ºC for 5 h. The refinements of X-ray diffraction (XRD) patterns obtained by the Rietveld method sugges
Mat. Res.. Publicado em: 11/01/2018
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28. Synthesis and Characterization of LiCoO2 from Different Precursors by Sol-Gel Method
Lithium cobalt oxide, LiCoO2, widely used as cathode in lithium ion batteries was synthesized and their structural and electronic properties investigated. The crystalline powders were prepared by the sol-gel method with four complexing agents: citric acid, glycine, starch and gelatin. These syntheses were compared with the blank test (without complexing agen
J. Braz. Chem. Soc.. Publicado em: 2017-11
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29. Effect of dissolution kinetics on flotation response of calcite with oleate
Abstract Phosphate flotation performance can be influenced by the dissolution kinetics of the minerals that compose the ore. The purpose of this work was to investigate the effect of dissolution kinetics on flotation response with oleate (collector) of calcites from different origins and genesis. The calcite samples were first purified and characterized by x
Braz. J. Chem. Eng.. Publicado em: 2017-10
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30. Structure and Physical Properties of the LaBiFe2O6 Perovskite Produced by the Modified Pechini Method
In this paper the synthesis of the LaBiFe2O6 material by the modified Pechini method is reported. Structural, morphologic, magnetic and optic experimental studies were performed. Rietveld refinement of x-ray diffraction patterns revealed that LaBiFe2O6 crystallizes in an orthorhombic perovskite structure (space group Pnma, # 62). Scanning electron microscopy
Mat. Res.. Publicado em: 24/07/2017
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31. A New Dynamic Powder Consolidation Technique Using Shock Waves
Techniques for shock consolidation of powders have been developed for different purposes, including the synthesis of diamond from carbon powder. In this work, a new device configuration for dynamic consolidation is proposed. It consists of three coaxial tubes, with a conical cover made of explosive at the top of the device. The inner tube contains the powder
Mat. Res.. Publicado em: 13/07/2017
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32. Kinetics of Thermal Transformation of Synthetic Al-Maghemites into Al-Hematites
ABSTRACT Maghemite (γ-Fe2O3) and hematite (α-Fe2O3) are important iron oxides in Brazilian soils derived from basalt. Maghemite can transform into hematite when exposed to high temperatures. However, isomorphic substitution (e.g., Al3+) may largely influence this process. We analyzed the kinetics of thermal transformation of Al-maghemites into Al-hematites
Rev. Bras. Ciênc. Solo. Publicado em: 27/04/2017
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33. Al and PEG Effect on Structural and Physicochemical Properties of CoFe2O4
In this work, pure and Alumina doped cobalt ferrite nanoparticles CoFe2−xAlxO4 (for x = 0.44) have been synthesized by the sol gel method. The influence of alumina doping on the morphological and mechanical properties of CoFe2O4 nano-particles were investigated by means of X-ray powder diffraction (XRD) and rietveld analysis. XRD analysis confirmed that th
Mat. Res.. Publicado em: 06/03/2017
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34. Kinetics of Formation and Crystal Structure Determination of Sr4Al6O12SO4
The sulphoaluminate of strontium, Sr4Al6O12SO4, was synthesized by solid state reaction from mixture of SrCO3, Al2O3 and SrSO4 (3:3:1 molar ratio) as pellets. The kinetics of formation has been studied in the range of temperature between 850ºC and 1100ºC using quantitative X-ray powder diffraction data (XRD) analysis. Likewise, at room temperature, the cry
Mat. Res.. Publicado em: 09/02/2017
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35. Rietveld Method in the Analysis of Polymorphism in Mebendazole Tablets Acquired in Brazil’s Drugstores
Mebendazole (MBZ) is an anthelmintic medicine known to exhibit the polymorphs A, B and C, where polymorph C is the one indicated for tablets. Mebendazole commercial tablets (references, generics and similars) were analyzed in this work using X-ray powder diffraction data and the Rietveld method (RM) aiming at characterizing and quantifying crystal phases. Fo
J. Braz. Chem. Soc.. Publicado em: 2015-09
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36. Abrasive blasting contamination in Super Duplex and carbon steels - a quantification approach by rietveld analysis
A methodology for quantifying the contamination after abrasive blasting by Aluminum Oxide and Martensitic Carbon Steel particles in Super Duplex and Carbon Steel substrates has been developed. The method consisted of performing x-ray diffraction in the blasted steel substrates and calculating the particle contamination using Rietveld Quantitative Method. In
Mat. Res.. Publicado em: 2014-10