scholarly journals Solidified Fillings of Nanopores

2005 ◽  
Vol 876 ◽  
Author(s):  
Patrick Huber ◽  
Klaus Knorr
Keyword(s):  
Pore Diameter ◽  
Stacking Faults ◽  
Pore Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Medium Length ◽  
Close Packed Structure ◽  
Packed Structure ◽  
Diffraction Patterns ◽  
Selection Of

AbstractWe present a selection of x-ray diffraction patterns of spherical (He, Ar), dumbbell- (N2, CO), and chain-like molecules (n-C9H20, n-C19H40) solidified in nanopores of silica glass (mean pore diameter 7nm). These patterns allow us to demonstrate how key principles governing crystallization have to be adapted in order to accomplish solidification in restricted geometries. 4He, Ar, and the spherical close packed phases of CO and N2 adjust to the pore geometry by introducing a sizeable amount of stacking faults. For the pore solidified, medium-length chainlike n-C19H40 we observe a close packed structure without lamellar ordering, whereas for the short-chain C9H20 the layering principle survives, albeit in a modified fashion compared to the bulk phase.

Powder diffraction analysis of an interstratified marcasite/pyrite structure

1995 ◽  
Vol 10 (3) ◽  
pp. 198-203 ◽  
Author(s):  
Neil E. Johnson ◽  
Sidney S. Pollack ◽  
Elizabeth A. Frommell ◽  
Patricia A. Eldredge
Keyword(s):  
Catalytic Activity ◽  
Stacking Faults ◽  
Catalyst Precursor ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Naturally Occurring ◽  
Benzylic Carbon ◽  
Diffraction Peaks ◽  
Diffraction Patterns

A synthetic catalyst precursor formed by sulfiding ferrihydrite (Fe3+O(OH)) in the presence of a hydrogen donor produces X-ray diffraction patterns resembling a mixture of both naturally occurring FeS2 polymorphs marcasite and pyrite. The diffraction peaks display a differential broadening, however, wherein only those peaks coincident to both marcasite and pyrite are strong and sharp, a feature that cannot be accounted for by a simple physical mixture. The broadening is analogous to that found in hexagonal cobalt, where occasional stacking faults produce interstratification of the hexagonal and cubic close-packed forms, resulting in strongly coherent diffraction only along the stacking direction. The crystal structures of marcasite and pyrite are virtually identical if viewed perpendicular to the (101) and (001) planes, respectively. Calculation of diffraction patterns based upon models of interstratifying marcasite and pyrite layers along these planes demonstrates that a sequence with marcasite-to-pyrite and pyrite-to-marcasite stacking fault probabilities of 0.22 provides a good fit to the experimental pattern. This interstratified material is a precursor to a species that shows catalytic activity for cleaving C-C bonds between aromatic rings and benzylic carbon atoms at low (<350 °C) temperatures.

Stacking fault model of ∊-martensite and itsDIFFaXimplementation

2011 ◽  
Vol 44 (4) ◽  
pp. 779-787 ◽  
Author(s):  
Stefan Martin ◽  
Christiane Ullrich ◽  
Daniel Šimek ◽  
Ulrich Martin ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Electron Backscatter Diffraction ◽  
Stacking Faults ◽  
Stacking Fault ◽  
X Ray Diffraction ◽  
Contrast Imaging ◽  
X Ray ◽  
Austenitic Transformation ◽  
Electron Channelling ◽  
Diffraction Patterns

Plastic deformation of highly alloyed austenitic transformation-induced plasticity (TRIP) steels with low stacking fault energy leads typically to the formation of ∊-martensite within the original austenite. The ∊-martensite is often described as a phase having a hexagonal close-packed crystal structure. In this contribution, an alternative structure model is presented that describes ∊-martensite embedded in the austenitic matrixviaclustering of stacking faults in austenite. The applicability of the model was tested on experimental X-ray diffraction data measured on a CrMnNi TRIP steel after 15% compression. The model of clustered stacking faults was implemented in theDIFFaXroutine; the faulted austenite and ∊-martensite were represented by different stacking fault arrangements. The probabilities of the respective stacking fault arrangements were obtained from fitting the simulated X-ray diffraction patterns to the experimental data. The reliability of the model was proven by scanning and transmission electron microscopy. For visualization of the clusters of stacking faults, the scanning electron microscopy employed electron channelling contrast imaging and electron backscatter diffraction.

The Structure and Porosity of Fe62-xCo10WyMexY8B20-y Alloys in the Amorphous and Crystalline States (where: Me = Mo, Nb; x = 0, 1, 2; y = 0, 1, 2)

2017 ◽  
Vol 68 (1) ◽  
pp. 22-27
Author(s):  
Marcin Nabialek ◽  
Pawel Pietrusiewicz ◽  
Michal Szota ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Andrei Victor Sandu
Keyword(s):  
Pore Diameter ◽  
Copper Plate ◽  
X Ray Diffraction ◽  
Amorphous Halo ◽  
Casting Method ◽  
Average Pore ◽  
X Ray ◽  
Crystallization Method ◽  
Injection Casting ◽  
Diffraction Patterns

The investigated crystalline and amorphous samples were obtained by crystallization of the liquid alloy on a water-cooled copper plate and by an injection-casting method, respectively. In each case, the structure of the samples was determined by examination of the obtained X-ray diffraction patterns. The diffraction patterns of samples produced by the injection casting method were characterized by a single broad peak called the amorphous halo. The samples produced by the crystallization method were shown to feature within their structure the following phases:YB2, Fe2Y, �-Fe, Co5Y, and B6Co23. Further research, performed using computer tomography, revealed the existence of pores within the samples. The crystalline-structure samples were found to feature a lower average pore diameter.

Rietveld Analysis of Ceramic Nuclear Waste Forms

1993 ◽  
Vol 333 ◽  
Author(s):  
T.J. White ◽  
H. Mitamura
Keyword(s):  
Rietveld Method ◽  
Amorphous Material ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Waste Forms ◽  
Simulated Waste ◽  
Diffraction Patterns ◽  
Nuclear Waste Forms ◽  
Selection Of

ABSTRACTPowder X-ray diffraction patterns were collected from three titanate waste forms - a calcine powder, a prototype ceramic without waste, and a ceramic containing 10 wt% JW-A simulated waste - and interpreted quantitatively using the Rietveld method. The calcine consisted of fluorite, pyrochlore, rutile, and amorphous material. The prototype waste form contained rutile, hollandite, zirconolite and perovskite. The phase constitution of the JW-A ceramic was freudenbergite, loveringite, hollandite, zirconolite, perovskite and baddeleyite. Procedures for the collection of X-ray data are described, as are assumptions inherent in the Rietveld approach. A selection of refined crystal data are presented.

Structural and Electronic Studies of C60 Films Deposited Using a New Technique of Neutral Cluster Beam Deposition

1994 ◽  
Vol 349 ◽  
Author(s):  
Zhong-Min Ren ◽  
Zhi-Feng Ying ◽  
Xia-Xing Xiong ◽  
Mao-Qi He ◽  
Yuan-Cheng Du ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Neutral Cluster ◽  
X Ray ◽  
Close Packed Structure ◽  
Oxygen Contamination ◽  
Packed Structure ◽  
A New Technique ◽  
Cluster Beams ◽  
Cluster Beam Deposition

ABSTRACTC50 films, are deposited on Si(111) substrates using neutral cluster beams of fullerenes generated from a crucible with a special nozzle. X-ray diffraction (XRD) have been used to investigate the structural properties of C50 films, which indicate highly textural films as close-packed structure with strong (110) XRD assignment and 400Å for correlation length. Raman spectrum indicates the existence of stable C60 films. X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) measurements are carried out to analyze the electronic properties of the films. The resistivity to contamination of C50 film deposited here is better than that deposited by MBE. Different kinds of oxygen contamination on the surfaces of C50 films and HDPG are detected by the results of O 1s XPS analyses.

Cu2ZnSnSe4 thin films prepared by selenization of precursor evaporated from Cu2ZnSnSe4 and Na2Se

2014 ◽  
Vol 1603 ◽  
Author(s):  
Mitsuki Nakashima ◽  
Toshiyuki Yamaguchi ◽  
Masanobu Izaki
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thin Film Solar Cells ◽  
X Ray Diffraction ◽  
X Ray ◽  
Epma Analysis ◽  
Close Packed Structure ◽  
Columnar Grains ◽  
Packed Structure ◽  
Selenization Process

ABSTRACTCu2ZnSnSe4 thin films were prepared by using the synthesized Cu2ZnSnSe4 ingot and Na2Se powder at various Na2Se/Cu2ZnSnSe4 mole ratio as evaporation materials for selenization process. From EPMA analysis, the composition was approximately constant even if the Na2Se/Cu2ZnSnSe4 mole ratio increased. X-ray diffraction studies revealed that the thin films had a kesterite Cu2ZnSnSe4 structure and the foreign phases disappeared with increasing the Na2Se/Cu2ZnSnSe4 mole ratio. The Na2Se addition enhanced to grow thin films having a close-packed structure and columnar grains. The values of Voc and Isc in Cu2ZnSnSe4 thin film solar cells increased with increasing the Na2Se/Cu2ZnSnSe4 mole ratio.

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.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

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