The Determination of α-Cristobalite in Airborne Dust by X-Ray Diffraction — Theory and Practice

1989 ◽  
pp. 585-592
Author(s):  
M. Jeyaratnam ◽  
N. G. West
Keyword(s):  
Diffraction Theory ◽  
Theory And Practice ◽  
X Ray Diffraction ◽  
Airborne Dust ◽  
X Ray

Determination of Thickness of Multiple Layer Thin Films by X-ray Diffraction Technique

1995 ◽  
Vol 39 ◽  
pp. 637-643
Author(s):  
J. Chaudhuri ◽  
F. Hashmi
Keyword(s):  
Thin Films ◽  
Diffraction Theory ◽  
Scanning Electron Microscopy Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multiple Layer ◽  
Crystal Model ◽  
Microscopy Data ◽  
Secondary Extinction

In this study, the equations based on x-ray diffraction theory were developed to determine the thickness of multiple layer thin films. The kinematical expression of the integrated reflected intensity from the substrate and films was corrected for the primary and secondary extinction effects assuming a mosaic crystal model. As an example of the application of the method, thicknesses of a double heterostructure system, namely AlAs/AIGaAs/GaAs, were determined. Good agreement was obtained between the results from the x-ray measurement and scanning electron microscopy data demonstrating high precision of this technique.

Rapid Composition-Depth With X-Ray Diffraction: Theory and Practice

1985 ◽  
Vol 29 ◽  
pp. 193-202
Author(s):  
Karl E. Wiedemann ◽  
Jalaiah Unnam
Keyword(s):  
Diffraction Theory ◽  
Lattice Parameter ◽  
Crystal Defects ◽  
Theory And Practice ◽  
X Ray Diffraction ◽  
Parameter Calibration ◽  
X Ray ◽  
Depth Profiles ◽  
Deconvolution Techniques ◽  
Composition Depth Profile

AbstractHigh precision composition-depth profiles can be determined quickly using a recent development. This method requires that noncompositional broadening arising from the instrument, crystal defects, and the radiation source be removed from the diffraction pattern before calculating the composition-depth profile. Effective deconvolution techniques, profiling theory, methodology of profiling, and the effect of residual noncompositional broadening on the profile are discussed. Examples include statistical analyses of error in the profile due to random counting errors and variance in the lattice parameter calibration.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

New Coordination Compounds of Fe(III) with Organic Ligands

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihaela Flondor ◽  
Ioan Rosca ◽  
Doina Sibiescu ◽  
Mihaela-Aurelia Vizitiu ◽  
Daniel-Mircea Sutiman ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Complex Compounds ◽  
Organic Ligands ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Chemical Analysis ◽  
Structural Formulae ◽  
Paramagnetic Properties

In this paper the synthesis and the study of some complex compounds of Fe(III) with ligands derived from: 2-(4-chloro-phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (HL1), 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsulfanyl-ethanone(HL2), and 2-(4-chloro-phenylsulfanyl)-1-(3,5-dibromo-2-hydroxy-phenyl)-ethanone (HL3) is presented. The characterization of these complexes is based on method as: the elemental chemical analysis, IR and ESR spectroscopy, M�ssbauer, the thermogravimetric analysis and X-ray diffraction. Study of the IR and chemical analysis has evidenced that the precipitates form are a complexes and the combination ratio of M:L is 1:2. The central atoms of Fe(III) presented paramagnetic properties and a octaedric hybridization. Starting from this precipitation reactions, a method for the gravimetric determination of Fe(III) with this organic ligands has been possible. Based on the experimental data on literature indications, the structural formulae of the complex compounds are assigned.

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