Results 251 to 260 of about 17,786 (291)

Rietveld Structure Refinement of Zeolite ECR-1

Chemistry of Materials, 2005
In this work, we present the structure refinement of ECR-1 to give the first direct evidence of the proposed structure of this synthetic zeolite. In fact, a model of the structure of ECR-1 was proposed on the basis of high-resolution transmission electron microscopy (HRTEM) evidence and the structure solution of the synthetic gallo-silicate TNU-7, but ...
GUALTIERI, Alessandro, S. FERRARI, GALLI, Ermanno, F. DI RENZO, W. VAN BEEK   +4 more
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A rietveld refinement of NaCl-type Ca5Y4S11

Journal of Solid State Chemistry, 1995
The crystal structure of Ca{sub 5}Y{sub 4}S{sub 11} [a = 6.942(1) {angstrom}, {alpha} = 33.380(5){degrees}, space group R3m, No. 166, Z = (2/11), D{sub x} = 3.042 g cm{sup -3}] was determined using Rietveld refinement of X-ray powder diffraction data collected with CuK{alpha}{sub 1} radiation using a Guiner-Haegg camera.
John G. Thompson, Ray L. Withers, L.Carlos Otero-Diaz   +2 more
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Rietveld refinement study of pyrite crystals

Journal of Alloys and Compounds, 2005
Abstract Rietveld refinement was performed for two samples prepared from natural pyrite (a polymorph of iron disulphide or iron persulphide, FeS 2 ) single crystals originating from Navajun (Spain) and from Ural Mts. (Russia). The present refinements provide the following crystallographic data: a  = 5.41784(2) and 5.41819(2) A, x  = 0.3848(1) and 0.
W. Paszkowicz, J.A. Leiro
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Strontium in the collinsite structure: Rietveld refinement

Crystallography Reports, 2003
The crystal structure of a strontium variety of a rare phosphate—mineral collinsite (Ca2 − x Srx)2Mg[PO4] · 2H2O was solved from powder X-ray diffraction data (λ CuK α radiation, Ni filter, 12.36° ≤ 2θ ≤ 100.00°, scan step 0.02°, exposure time per step 15 s) by the Rietveld method (R wp = 4.15%, R F = 1.03%, R B = 2.46%); a = 5.8219(1) A, b = 6.8319(2)
O. V. Yakubovich, Yu. K. Kabalov, P. G. Gavrilenko, R. P. Liferovich, W. Massa   +4 more
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Synthesis and rietveld refinement of MgO nanoparticles

AIP Conference Proceedings, 2020
Magnesium oxide (MgO) nanoparticles were synthesized using nitrate-citrate sol-gel route and the sample yield was annealed at 300°C, 450°C and 700°C for getting size distribution. Structural characterization was done by powder X-ray diffraction (XRD) measurements.
Himani Bhoi, Pragya Joshi, Khushboo Punia, Ganesh Lal, Sudhish Kumar   +4 more
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Crystal structure of zirconia by Rietveld refinement

Science in China Series A: Mathematics, 1999
The crystal structures and phase transformation of zirconia ceramics have been investigated by means of X-ray powder diffraction and Rietveld powder diffraction profile fitting technique. A structural transition from monoclinic to tetragonal occurs when Y2O3 and2 are doped into zirconia. The space group of the tetragonal structure is P42/nmc,Z=2.
Daning Wang, Yongquan Guo, Kaiming Liang, Kun Tao   +3 more
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Structure of α-polypivalolactone: a refinement based on the Rietveld method

Polymer, 1988
Abstract A comparative study is carried out on the structure of the α form of polypivalolactone obtained (i) from the analysis of oriented-fibre X-ray diffraction diagrams, (ii) from conformational energy calculations and (iii) by refining the first two models through best fitting on the powder X-ray diffraction profile according to the Rietveld ...
BRUCKNER S., MEILLE, STEFANO VALDO, PORZIO W.   +2 more
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Mathematical aspects of Rietveld refinement

1993
Abstract The method of least squares is a powerful technique for estimating the values of the adjustable parameters in a model, M(x), that predicts the values of a set of observable quantities, y. One seeks the minimum, as a function of x, of the quadratic form.
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Rietveld refinement and electrical properties of LiTiFeO4

AIP Conference Proceedings, 2017
Nanoparticles of Ti4+ substituted lithium ferrite LiTiFeO4 were prepared by the sol-gel auto combustion method. The sintered sample was characterized by X-ray diffraction to study the structural properties. The crystallite size obtained by Scherrer formula using XRD data is 22nm. The Rietveld refinement of the obtained XRD pattern was carried out using
Jitendra S. Kounsalye, Ashok V. Humbe, Pankaj P. Khirade, Apparao R. Chavan, K. M. Jadhav   +4 more
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Chapter 9. Rietveld Refinement

2008
A polycrystalline powder can be represented in reciprocal space as a set of nested spherical shells positioned with their centers at the origin1(Figure 9.1). These shells arise from the reciprocal lattice points from the myriad (e.g.
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