Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Shock Wave Compression of NaCl Single Crystals observed by Flash-X-Ray Diffraction

1978 ◽  
Vol 33 (8) ◽  
pp. 918-923 ◽  
Author(s):  
F. Müller ◽  
E. Schulte
Keyword(s):  
Shock Wave ◽  
Single Crystals ◽  
Observation Time ◽  
Plane Shock ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wave Compression ◽  
Shock Wave Compression ◽  
Diffraction Patterns ◽  
Set Up

Flash-x-ray-diffraction patterns (FXD) with an exposure time of 4 ns of NaCl single crystals compressed by plane shock waves are obtained at pressures of about 30 kbar. From the diffraction patterns the compression is determined and compared with Hugoniot data. During shock load the lattice shows an uniaxial compression. While in case of measurements at the free surface an observation time of only a few nanoseconds is available, this experimental set-up allows an observation time of two microseconds.

High Density Bulk Shape Rapid Consolidation of the Yba2Cu307-X Superconductor

1989 ◽  
Vol 169 ◽  
Author(s):  
S. V. Rele ◽  
R. V. Raman ◽  
H. S. Meeks ◽  
R. L. Anderson ◽  
R. N. Shelton ◽  
...  
Keyword(s):  
Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Volume Fraction ◽  
One Step ◽  
Hollow Cylinders ◽  
Diffraction Patterns ◽  
Set Up ◽  
Cylinders And Spheres ◽  
High Processing

AbstractA novel rapid densification technique for fabrication of bulk shape YBa2Cu307–xsuperconductor is presented. The Ceracon process is a one‐step, quasi‐isostatic consolidation route utilizing conventional P/M equipment and set‐up. The Ceracon technology has enabled successful fabrication of bulk, shapes such as discs, cylinders, hollow cylinders and spheres along with significant increases in the density up to 95‐98% of the theorertical. The superconducting volume fraction is preserved due to short hold times at the operating temperatures and avoidance of high processing temperatures. Results based on densities, microstructure, susceptibility measurements, X‐ray diffraction patterns and TGA measurements are discussed.

scholarly journals X-Ray Diffraction from Magnetically Oriented Microcrystal Suspension

2014 ◽  
Vol 70 (a1) ◽  
pp. C1136-C1136
Author(s):  
Kazuaki Aburaya ◽  
Chiaki Tsuboi ◽  
Fumiko Kimura ◽  
Kenji Matsumoto ◽  
Masataka Maeyama ◽  
...  
Keyword(s):  
Single Crystal ◽  
Magnetic Circuit ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
Uv Curable ◽  
X Ray ◽  
Novel Method ◽  
Diffraction Patterns ◽  
Magnetic Field Generator

A three dimensionally magnetically oriented microcrystal array (3D-MOMA) is attractive to determination of a crystal structure as well as a molecular structure because it does not require a single crystal with sufficient size and quality for diffraction studies. We have developed a novel method to fabricate 3D-MOMA and determined several crystal structures using the 3D-MOMAs[1],[2]. However, the structure determination through MOMA requires a solidification treatment with UV curable monomer prior to X-ray diffraction experiment. We have developed a new X-ray diffractometer equipped with a magnetic field generator, which makes it possible to collect diffraction data without the solidification treatment. In this poster, we describe X-ray diffraction analyses of a magnetically oriented microcrystal suspension (MOMS) of L-alanine without the solidification treatment. A suspension of L-alanine microcrystals was poured in a glass capillary and rotated at a constant speed in a magnetic circuit attached in the X-ray diffractometer. Then, diffraction images were collected every 60 seconds. In the initial phase, the diffraction pattern showed a broad shape similar to that from a powder sample. As time goes on, diffraction patterns have gradually changed to single-crystal like patterns. After 2 hours, the shape of diffraction spots became as sharp as that of a single crystal. This observation shows that the microcrystals are oriented in the same direction. Owing to the improvement of the magnetic circuit and X-ray diffractometer, the quality of the diffraction has been greatly improved compared to that reported previously[3]. Further details of the analyses will be shown in the poster.

scholarly journals Liquid-Phase Catalytic Oxidation of Limonene to Carvone over ZIF-67(Co)

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 374 ◽  
Author(s):  
Yizhou Li ◽  
Yepeng Yang ◽  
Daomei Chen ◽  
Zhifang Luo ◽  
Wei Wang ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Catalytic Oxidation ◽  
Heterogeneous Catalyst ◽  
Product Selectivity ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Mild Conditions ◽  
Before And After ◽  
Diffraction Patterns

Liquid-phase catalytic oxidation of limonene was carried out under mild conditions, and carvone was produced in the presence of ZIF-67(Co), cobalt based zeolitic imidazolate framework, as catalyst, using t-butyl hydroperoxide (t-BHP) as oxidant and benzene as solvent. As a heterogeneous catalyst, the zeolitic imidazolate framework ZIF-67(Co) exhibited reasonable substrate–product selectivity (55.4%) and conversion (29.8%). Finally, the X-ray diffraction patterns of the catalyst before and after proved that ZIF-67(Co) acted as a heterogeneous catalyst, and can be reused without losing its activity to a great extent.

X-Ray Diffraction and Electron-Microscope Studies of the Brush Border Membrane of Guinea Pig Intestinal Epithelial Cells

1970 ◽  
Vol 7 (2) ◽  
pp. 373-386
Author(s):  
A. R. LIMBRICK ◽  
J. B. FINEAN
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Intestinal Epithelial Cells ◽  
Electron Density Profile ◽  
Molecular Organization ◽  
Intestinal Epithelial ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Condensed Systems

Low-angle X-ray diffraction patterns have been obtained from condensed systems of brush border membranes which contain up to 30% water and also from hydrated samples of the lipid extracts of the membranes. The diffraction bands obtained from the hydrated membranes were orders (up to n=8) of a lamellar repeating unit of about 30 nm which included 2 membrane units. By referring to electron micrographs of these condensed membrane preparations, an electron density profile of the brush border membrane has been evaluated, and its significance in relation to the molecular organization of the membrane is discussed.

Developments in Analytical Diffraction Using Isotopic X-Ray Sources

1970 ◽  
Vol 14 ◽  
pp. 139-145
Author(s):  
W. S. Toothacker ◽  
L. E. Preuss
Keyword(s):  
Exposure Time ◽  
Specific Activity ◽  
X Rays ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Oak Ridge ◽  
Position Sensitive ◽  
Diffraction Patterns ◽  
Intense Source

AbstractLobov et al., in Leningrad, and workers at this laboratory have been working on the idea of using x rays from radioactive sources for x ray diffraction analysis. The Russians have been using iron-55 produced by the (n, Y) reaction in their work with a small focusing camera which operates in the back reflection region. We have been using iron-55 produced by the (p,n) reaction in conjunction with a small Debye-Scherrer camera. The preliminary work of this laboratory was reported at this conference two years ago. At that time a 13 mCi iron-55 source was used in a two inch diameter Debye-Scherrer camera to obtain x-ray diffraction patterns of LiF. The exposure times were of the order of 120 hours and the reflection from the 200 plane was about 3 degrees wide. Since that time a new and more intense source has been constructed at Oak Ridge National Laboratories. With the new source it was possible to produce LiF diffraction patterns of the same density and resolution as before in a period of less than ten hours.The above mentioned diffraction patterns were made with the LiF powder placed in a 1.0 mm diameter glass capillary. After reduction of the glass capillary diameter to 0.5 mm and appropriate reduction of the collimator width, we were able to improve the resolution considerably with no accompanying reduction in line density. The LiF patterns obtained in this way required an exposure time of about 20 hours and the width of the reflection from the 200 plane has been reduced to about 1.5 degrees.Hence we are able to report a reduction in exposure time from 116 hours to 20 hours and an increase in resolution by a factor of two over the data reported here two years ago. Thus the concept of using x rays from an isotope for powder diffraction has changed from a laboratory curiosity into a technique with practical possibilities. Both sources mentioned above were produced by the (p, n) reaction. The 135 mCi source had a specific activity of about 400 Ci/gm. Since iron-55 sources have been made with specific activities of about 1000 Ci/gm, a considerable decrease in exposure time could be accomplished by using such a source. The application to this work of a position sensitive proportional counter as developed by Semmler will also be discussed.

Evidence for cooling-rate-dependent icosahedral short-range order in a Cu–Zr–Al metallic glass

2014 ◽  
Vol 47 (6) ◽  
pp. 1906-1911 ◽  
Author(s):  
Helmut Hermann ◽  
Uta Kühn ◽  
Horst Wendrock ◽  
Valentin Kokotin ◽  
Björn Schwarz
Keyword(s):  
Metallic Glass ◽  
Cooling Rate ◽  
Short Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rate Dependent ◽  
Icosahedral Clusters ◽  
Thermal Displacements ◽  
The Difference ◽  
Diffraction Patterns

Samples of Cu47.5Zr47.5Al5metallic glass were prepared at different cooling rate,R. The dependence of the X-ray diffraction patterns onRwas analysed by comparing them with corresponding patterns of computer-simulated models generated at different cooling rates as well. The observed changes in the experimental diffraction patterns are reproduced by the simulations, showing an increasing fraction of icosahedral clusters with decreasing cooling rate. The difference of the fractions of icosahedrally coordinated atoms in mould-cast and rapidly quenched Cu47.5Zr47.5Al5averages to 3 (1)%. Different frozen-in thermal displacements and different density are ruled out as a possible origin for the experimental observations.

Residual stress measurement on the I12 JEEP beamline at Diamond Light Source

2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
A. M. Korsunsky ◽  
X. Song ◽  
F. Hofmann ◽  
B. Abbey ◽  
M. Xie ◽  
...  
Keyword(s):  
Light Source ◽  
Stress Measurement ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Loading Direction ◽  
Diffraction Patterns ◽  
Set Up ◽  
Energy Dispersive Diffraction

One of the multiple capabilities of the new Joint Engineering, Environmental and Processing (JEEP) beamline I12 at Diamond Light Source is the set-up for polychromatic high-energy X-ray diffraction for the study of polycrystalline deformation and residual stresses. The results and interpretation of the first experiments carried out on JEEP are reported. Energy dispersive diffraction patterns from titanium alloy Ti-6Al-4V were collected using the new 23-cell ‘horseshoe’ detector and interpreted using Pawley refinement to determine the residual elastic strains at the macro- and meso-scale. It provides a clear demonstration of the tensile-compressive hardening asymmetry of the hexagonal close-packed grains oriented with the basal plane perpendicular to the loading direction.

Carbonization Effect on Phase Structures of Zirconium Oxides with 2-3 Percent Yttrium

2014 ◽  
Vol 936 ◽  
pp. 181-186
Author(s):  
Zhi Qin Xue ◽  
Yong Quan Guo
Keyword(s):  
Tetragonal Phase ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconium Oxides ◽  
Percent Yttrium ◽  
Before And After ◽  
Cubic Structure ◽  
Diffraction Patterns ◽  
Rietveld Structural Refinement

Phase evolutions and structures of zirconium oxides with 2 percent yttrium before and after carbonization have been systemically studied with X-ray diffraction and Rietveld structural refinement. The carbonization decreases the structural stability of original ZrO2. According to the X-ray diffraction patterns, three phases with monoclinic, tetragonal and cubic structure coexist after carbonization. With increasing carbonizing temperature, the content of tetragonal phase in ZrO2with 2% mol Y2O3 doped increases，however, the phase content of monoclinic phase decreases. The content of tetragonal phase in ZrO2with 3% mol Y2O3doped increases greatly after carbonization. It implies that carbonization is beneficial for the formation of ZrO2tetragonal phase.

Reactive Adsorption of Sulfur Compounds from FCC Gasoline on NiO/γ-Al2O3

2009 ◽  
Vol 79-82 ◽  
pp. 2219-2222 ◽  
Author(s):  
Hai Yan Yin ◽  
Chun Hu Li ◽  
Lin Xue Wang ◽  
Ying Min Yu
Keyword(s):  
Nitrogen Adsorption ◽  
Sulfur Compounds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fcc Gasoline ◽  
Reactive Adsorption ◽  
Before And After ◽  
Desulfurization Efficiency ◽  
Diffraction Patterns ◽  
Sulfur Adsorption

NiO/γ-Al2O3 adsorbent was prepared by wet impregnated method. XRD, SEM-EDS, nitrogen adsorption techniques were used to characterize the adsorbents and GC-FPD was utilized to analyze the composition of gasoline before and after reaction. X-ray diffraction patterns indicate that noncrystal NiO particles are supported on the surface of γ-Al2O3. The results show that NiO/γ-Al2O3 adsorbent could be used to remove sulfur compounds and is effective on removing benzothiophene (BT). The maximum desulfurization efficiency appears when NiO content reaches 16%, and the total sulfur adsorption capacity is 1.84mg/g, however for 16%Ni/γ-Al2O3 the value reaches 3.495mg/g.

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