Influence of temperature and point defects on the X-ray diffraction pattern of graphite

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.

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Cytomembrane Preservation in Tissue Dehydrated Only With Glutaraldehyde and Epon 812 Resin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072046 ◽

1973 ◽

Vol 31 ◽

pp. 320-321

Author(s):

Daniel C. Pease

Keyword(s):

Diffraction Pattern ◽

X Ray Diffraction ◽

High Concentration ◽

Unpublished Study ◽

X Ray ◽

Sectioned Material

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 An associated (unpublished) study, carried out in co-operation with Drs.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.

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Pearl Testing Through only One X-Ray Diffraction Pattern

The Journal of Gemmology ◽

10.15506/jog.1962.8.7.251 ◽

1962 ◽

Vol 8 (7) ◽

pp. 251-252

Author(s):

Jorge Angus

Keyword(s):

Diffraction Pattern ◽

X Ray Diffraction ◽

X Ray

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Efficient methods of X-ray diffraction pattern inversion

Results in Physics ◽

10.1016/j.rinp.2019.102605 ◽

2019 ◽

Vol 15 ◽

pp. 102605

Author(s):

Ian Gregory Shuttleworth

Keyword(s):

Diffraction Pattern ◽

X Ray Diffraction ◽

X Ray

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X-ray diffraction analysis of matter taking into account the second harmonic in the scattering of powerful ultrashort pulses of an electromagnetic field

Scientific Reports ◽

10.1038/s41598-021-83183-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

M. K. Eseev ◽

A. A. Goshev ◽

K. A. Makarova ◽

D. N. Makarov

Keyword(s):

Electromagnetic Field ◽

Diffraction Analysis ◽

Diffraction Pattern ◽

Second Harmonic ◽

Ultrashort Pulses ◽

X Ray Diffraction ◽

X Ray ◽

Scattering Spectra ◽

Technical Possibility ◽

2D And 3D

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.

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The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

Scientific Reports ◽

10.1038/s41598-021-81017-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mikolaj Grabowski ◽

Ewa Grzanka ◽

Szymon Grzanka ◽

Artur Lachowski ◽

Julita Smalc-Koziorowska ◽

...

Keyword(s):

Quantum Wells ◽

High Temperatures ◽

Point Defects ◽

X Ray Diffraction ◽

Helium Ions ◽

X Ray ◽

Sapphire Substrates ◽

Transmission Electron ◽

The Impact ◽

Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

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The crystal structures and mechanical properties of the uranyl carbonate minerals roubaultite, fontanite, sharpite, widenmannite, grimselite and čejkaite

Inorganic Chemistry Frontiers ◽

10.1039/d0qi00933d ◽

2020 ◽

Vol 7 (21) ◽

pp. 4197-4221 ◽

Cited By ~ 1

Author(s):

Francisco Colmenero ◽

Jakub Plášil ◽

Jiří Sejkora

Keyword(s):

Mechanical Properties ◽

Hydrogen Bonding ◽

Diffraction Pattern ◽

Crystal Structures ◽

First Principles ◽

X Ray Diffraction ◽

Carbonate Minerals ◽

X Ray ◽

Uranyl Carbonate

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.

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Modeling the X-ray diffraction pattern of opal-CT

American Mineralogist ◽

10.2138/am-1995-7-823 ◽

1995 ◽

Vol 80 (7-8) ◽

pp. 869-872 ◽

Cited By ~ 42

Author(s):

George D. Guthrie ◽

David L. Bish ◽

Robert C. Reynolds

Keyword(s):

Diffraction Pattern ◽

X Ray Diffraction ◽

X Ray

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PREPARATION OF ANTIMONY-PLATINUM SURFACE ALLOY ELECTRODE BY ATOM DIFFUSION IN THE SOLID PHASE

International Journal of Modern Physics B ◽

10.1142/s0217979206040751 ◽

2006 ◽

Vol 20 (25n27) ◽

pp. 3999-4004

Author(s):

HIROSHI MATSUI ◽

KAZUFUMI WATANABE

Keyword(s):

Diffraction Pattern ◽

Low Temperatures ◽

Solid Phase ◽

Electrochemical Measurement ◽

X Ray Diffraction ◽

Platinum Surface ◽

X Ray ◽

Atom Diffusion ◽

Heat Treated ◽

Titanium Substrates

Antimony-platinum bilayers were prepared on titanium substrates by the two-step electrodeposition in the usual baths, and then surface alloys were formed by the atom diffusion in the solid phase. The simple antimony layer was little influenced by the substrate in both the measurements of X-ray diffraction and the i - E characteristic in a sulfuric acid solution. Regarding the bilayers, the catalytic activity in hydrogen evolution reaction was very sensitive to the presence of platinum, while the hydrogen adsorbability was quite insensitive. An interaction between antimony and platinum was confirmed by the appearance of a new dissolution wave in the electrochemical measurement and the occurrence of a new diffraction in the X-ray diffraction pattern after the heat-treatment of about 400°C. Although the new diffraction disagreed with any of the reported alloys, clear diffraction pattern of PtSb 2 alloy was observed, when the bilayers were heat-treated at about 600°C for one hour. Considering the penetration depth of X-ray, the alloying of antimony and platinum seems to occur also at low temperatures at least at the top surface.

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