scholarly journals Local Structure EXAFS Study of Nd2CuO4and Nd1.85Ce0.15CuO4Using Multiple-Scattering Data-Analysis

1997 ◽  
Vol 7 (C2) ◽  
pp. C2-1237-C2-1238 ◽  
Author(s):  
F. Sperandini ◽  
A. Di Cicco
Keyword(s):  
Data Analysis ◽  
Multiple Scattering ◽  
Local Structure ◽  
Scattering Data ◽  
Exafs Study

XANES and EXAFS of YBa2Cu3O≈7: Multiple scattering data analysis and evidence for a structural distortion at Tc

1989 ◽  
Vol 158 (1-3) ◽  
pp. 469-470 ◽  
Author(s):  
S. Della Longa ◽  
A. Di Cicco ◽  
S. Stizza ◽  
M. De Santis ◽  
K. Garg ◽  
...  
Keyword(s):  
Data Analysis ◽  
Multiple Scattering ◽  
Structural Distortion ◽  
Scattering Data

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

scholarly journals Cramér-Rao Bound Study of Multiple Scattering Effects in Target Separation Estimation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Edwin A. Marengo ◽  
Paul Berestesky
Keyword(s):  
Multiple Scattering ◽  
Born Approximation ◽  
Single Scattering ◽  
Scattering Data ◽  
Approximation Model ◽  
Scattering Parameters ◽  
Helmholtz Operator ◽  
Scattering Effects ◽  
Cramer Rao Bound ◽  
Multiple Scattering Effects

The information about the distance of separation between two-point targets that is contained in scattering data is explored in the context of the scalar Helmholtz operator via the Fisher information and associated Cramér-Rao bound (CRB) relevant to unbiased target separation estimation. The CRB results are obtained for the exact multiple scattering model and, for reference, also for the single scattering or Born approximation model applicable to weak scatterers. The effects of the sensing configuration and the scattering parameters in target separation estimation are analyzed. Conditions under which the targets' separation cannot be estimated are discussed for both models. Conditions for multiple scattering to be useful or detrimental to target separation estimation are discussed and illustrated.

Characterization of alumina powder using multiple small-angle neutron scattering. I. Theory

1985 ◽  
Vol 18 (6) ◽  
pp. 467-472 ◽  
Author(s):  
N. F. Berk ◽  
K. A. Hardman-Rhyne
Keyword(s):  
Particle Size ◽  
Phase Shift ◽  
Neutron Scattering ◽  
Multiple Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Scattering Data ◽  
Alumina Powder ◽  
Beam Broadening

Microstructural parameters of high-purity alumina powder are determined quantitatively throughout the bulk of the material using small-angle neutron scattering techniques. A unified theoretical and experimental approach for analyzing multiple scattering data is developed to obtain values for particle size, volume fraction and surface area. It is shown how particle size and volume fraction can be measured in a practical way from SANS data totally dominated by incoherent multiple scattering (`beam broadening'). The general phase-shift dependence of single-particle scattering is incorporated into the multiple scattering formalism, and it is also shown that the diffractive limit (small phase shift) applies even for phase shifts as large as unity (particle radii of order 1 μm). The stability of the Porod law against multiple scattering and the phase-shift scale are described, a useful empirical formula for analysis of beam broadening data is exhibited, and the applicability of the formulations to polydispersed systems is discussed.

scholarly journals Global Small-Angle X-ray Scattering Data Analysis of Triacylglycerols in the Molten State (Part I)

2018 ◽  
Vol 122 (45) ◽  
pp. 10320-10329 ◽  
Author(s):  
Amin Sadeghpour ◽  
Marjorie Ladd Parada ◽  
Josélio Vieira ◽  
Megan Povey ◽  
Michael Rappolt
Keyword(s):  
Data Analysis ◽  
Small Angle ◽  
Scattering Data ◽  
Molten State ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Local structure of the MgxNixCoxCuxZnxO(x=0.2) entropy-stabilized oxide: An EXAFS study

2017 ◽  
Vol 100 (6) ◽  
pp. 2732-2738 ◽  
Author(s):  
Christina M. Rost ◽  
Zsolt Rak ◽  
Donald W. Brenner ◽  
Jon-Paul Maria
Keyword(s):  
Local Structure ◽  
Exafs Study

Multiple-scattering x-ray absorption investigation of the local structure around substitutional Ge impurities in Ag

1999 ◽  
Vol 60 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Adriano Filipponi ◽  
Michael Borowski ◽  
Francesca Natali
Keyword(s):  
Multiple Scattering ◽  
Local Structure ◽  
X Ray ◽  
X Ray Absorption

Local structure determination using total scattering data

2021 ◽  
Author(s):  
Simon J.L. Billinge ◽  
Sandra H. Skjaervoe ◽  
Maxwell W. Terban ◽  
Songsheng Tao ◽  
Long Yang ◽  
...  
Keyword(s):  
Structure Determination ◽  
Local Structure ◽  
Scattering Data ◽  
Total Scattering
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