scholarly journals Challenges in Rietveld Refinement and Structure Visualization in Ceramics

2021 ◽  
Author(s):  
Touseef Ahmad Para ◽  
Shaibal Kanti Sarkar

The most common and basic characterization in the field of material science is the almighty X-ray diffraction (XRD). In every institute, every research report and every manuscript, concerning material properties, the X-ray diffraction pattern is essentially found. Although the basis of these works relies on the fact that X-ray diffraction pattern was found to be matching with some structure in a database, the in depth significance of the various characteristic diffraction manifestations of various physical characters are rarely discussed. Most of the researchers (especially beginners) are either not aware of the prowess of X-ray based characterizations, or have not been introduced to it properly or may be sometimes they are not interested in its results at all. The decreased interest (later) in the results from such studies might be for not being productive enough for time spending or non-effectiveness in justifying the motivation of the work. The former two are more related to the availability and accessibility of study material for the development of core concepts. Most of the institutes always do not have access to the span-wide scientific literature and the researchers joining these institutions are partly affected. In this context the effective open-access and free availability of intech-open, it is prudent to at least attempt to accumulate, assimilated and aggregate the concepts related to X-ray diffraction in a single package. The chapter is an attempt in the path of this route.

2013 ◽  
Vol 29 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Ana Palčić ◽  
Ivan Halasz ◽  
Josip Bronić

The crystal structure of copper(ii) citrate monohydrate (C6H4O7Cu2·H2O) has been solved from a mixture powder diffraction pattern. Approach to indexing, structure solution and Rietveld refinement of multiphase diffraction patterns is discussed. Rietveld refinement is carried out employing free-atom refinement and rigid body refinement.


2007 ◽  
Vol 63 (a1) ◽  
pp. s190-s190
Author(s):  
M. Dahbi ◽  
I. Saadoune ◽  
K. Edström ◽  
T. Gustafsson

Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.


Author(s):  
Daniel C. Pease

A previous study demonstrated that tissue could be successfully infiltrated with 50% glutaraldehyde, and then subsequently polymerized with urea to create an embedment which retained cytomembrane lipids in sectioned material. As a result, the 180-190 Å periodicity characteristic of fresh, mammalian myelin was preserved in sections, as was a brilliant birefringence, and the capacity to bind OsO4 vapor in the hydrophobic bilayers. An associated (unpublished) study, carried out in co-operation with Drs. C.K. Akers and D.F. Parsons, demonstrated that the high concentration of glutaraldehyde (and urea) did not significantly alter the X-ray diffraction pattern of aldehyde-fixed, myelin. Thus, by itself, 50% glutaraldehyde has little effect upon cytomembrane systems and can be used with confidence for the first stages of dehydration.


1962 ◽  
Vol 8 (7) ◽  
pp. 251-252
Author(s):  
Jorge Angus

2019 ◽  
Vol 15 ◽  
pp. 102605
Author(s):  
Ian Gregory Shuttleworth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. K. Eseev ◽  
A. A. Goshev ◽  
K. A. Makarova ◽  
D. N. Makarov

AbstractIt is well known that the scattering of ultrashort pulses (USPs) of an electromagnetic field in the X-ray frequency range can be used in diffraction analysis. When such USPs are scattered by various polyatomic objects, a diffraction pattern appears from which the structure of the object can be determined. Today, there is a technical possibility of creating powerful USP sources and the analysis of the scattering spectra of such pulses is a high-precision instrument for studying the structure of matter. As a rule, such scattering occurs at a frequency close to the carrier frequency of the incident USP. In this work, it is shown that for high-power USPs, where the magnetic component of USPs cannot be neglected, scattering at the second harmonic appears. The scattering of USPs by the second harmonic has a characteristic diffraction pattern which can be used to judge the structure of the scattering object; combining the scattering spectra at the first and second harmonics therefore greatly enhances the diffraction analysis of matter. Scattering spectra at the first and second harmonics are shown for various polyatomic objects: examples considered are 2D and 3D materials such as graphene, carbon nanotubes, and hybrid structures consisting of nanotubes. The theory developed in this work can be applied to various multivolume objects and is quite simple for X-ray structural analysis, because it is based on analytical expressions.


2020 ◽  
Vol 7 (21) ◽  
pp. 4197-4221 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Jiří Sejkora

The structure, hydrogen bonding, X-ray diffraction pattern and mechanical properties of six important uranyl carbonate minerals, roubaultite, fontanite, sharpite, widenmannite, grimselite and čejkaite, are determined using first principles methods.


1995 ◽  
Vol 80 (7-8) ◽  
pp. 869-872 ◽  
Author(s):  
George D. Guthrie ◽  
David L. Bish ◽  
Robert C. Reynolds

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