Density and Packing in Uranium Based Metallic Glasses

1985 ◽  
Vol 57 ◽  
Author(s):  
A. J. Drehman
Keyword(s):  
Metallic Glasses ◽  
Excess Volume ◽  
Nearest Neighbor ◽  
Glass Composition ◽  
Neighbor Distance ◽  
Compositional Dependence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Compositional Range ◽  
Nearest Neighbor Distance

AbstractDensity and x-ray diffraction measurements were performed over a wide compositional range of U-Fe and U-Co metallic glass ribbons. The compositional dependence of both the density and the average nearest neighbor distance exhibits a change in slope at approximately 28 at.% transition metal. This suggests an “ideal” glass composition possessing a minimum excess volume. A qualitative model of atomic packing is proposed, which is based on the compositional dependence of the atomic volume and nearest neighbor distance.

scholarly journals X-ray Diffraction Analysis of NdCl3 Melt

1990 ◽  
Vol 45 (5) ◽  
pp. 623-626 ◽  
Author(s):  
Kazuo Igarashi ◽  
Mineo Kosaka ◽  
Masahiro Ikeda ◽  
Junichi Mochinaga
Keyword(s):  
Coordination Number ◽  
Short Range ◽  
Nearest Neighbor ◽  
Correlation Method ◽  
Neighbor Distance ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Nearest Neighbor Distance ◽  
Short Range Structure

Abstract The structure of molten NdClj at 800 CC has been investigated by X-ray scattering and the correlation method. The nearest neighbor distance and coordination number of Nd-Cl are 2.77 Ä and 5.5 A, respectively. The Nd-Nd and CI-CI distances are 5.08 and 4.04 Ä, respectively. The average nearest neighbor distance and coordination number decrease markedly on melting, and the resulting short range structure of the melt is approximately octahedral

Nanocrystalline Solid Solutions of Cu/Co and Other Novel Nanomaterials

1996 ◽  
Vol 457 ◽  
Author(s):  
A. S. Edelstein ◽  
V. G. Harris ◽  
D. Rolison ◽  
J. H. Perepezko ◽  
D. Smith
Keyword(s):  
Heat Treatment ◽  
Lattice Constant ◽  
Solid Solutions ◽  
Nearest Neighbor ◽  
Neighbor Distance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vegard’S Law ◽  
Minimum Heat ◽  
Special Case

ABSTRACTA brief review will be given of the preparation, synthesis and properties of the Cu/Co system. The special case of the synthesis of nanocrystalline Cu.80Co.20 by precipitation and reduction of hydroxides is discussed in more detail. It was found that the lattice constant of nanocrystalline Cu.80Co.20. determined from x-ray diffraction measurements, approximately fits Vegard's Law and the average nearest neighbor distance from both the Cu and Co atoms, determined from EXAFS measurements, ir shifted from their bulk values. Samples given the minimum heat treatment needed to reduce the hydroxides contained Co-rich regions. Heat treatments cause the Co to segregate preferentially onto the surface of the Cu crystals. The presence of the Co delays the oxidation of the Cu surfaces.

Observations of coexistence of FCC and HCP phases in C60 by HREM

1992 ◽  
Vol 50 (1) ◽  
pp. 110-111
Author(s):  
Z.G. Li ◽  
Paul J. Fagan
Keyword(s):  
Carbon Atom ◽  
Crystalline Structure ◽  
Diffraction Data ◽  
Large Scale ◽  
Nearest Neighbor ◽  
Neighbor Distance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Correct Structure

Since the discovery of a large scale synthesis of fullerenes there has been intense interest in the structure of these materials. The first diffraction data suggested that crystalline C60 had a hexagonal close-packed (hep) structure with a nearest neighbor distance of 10.04 Å. The possibility of a disordered stacking of C60 molecules was first noted in this study. Since then, there has been some confusion regarding the exact crystalline structure of C60 as determined by electron and X-ray diffraction. In particular, a diffraction feature corresponding to a spacing of 8.7 Å has been noted in several studies. Recendy there had been a growing consensus that fcc is the correct structure for sublimed C60. Although the internal carbon atom arrangement of the C60 molecules cannot be determined, the actual packing and defects in C60 crystals over small and relatively large regions are readily seen by HRTEM. We have found by direct imaging a relatively large region of defect-free hep packing of C60 spheres sublimed onto a relatively cool microscopy grid.

Extended x-ray absorption fine structure study on amorphous Nd–Fe–B alloys

1998 ◽  
Vol 13 (8) ◽  
pp. 2132-2138 ◽  
Author(s):  
Hiroyuki Kageyama ◽  
Kohei Kadono ◽  
Kohei Fukumi ◽  
Tetsuji Saito ◽  
Toshiro Kuji
Keyword(s):  
Local Structure ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Nearest Neighbor ◽  
Amorphous Structure ◽  
Neighbor Distance ◽  
X Ray ◽  
Melt Spun ◽  
Nearest Neighbor Distance ◽  
X Ray Absorption

The local structure and crystallization behavior of Nd15Fe77Bx (x = 2−14) melt-spun alloys were studied by Nd L3 extended x-ray absorption fine structure (EXAFS). The conventional x-ray powder diffractometry studies showed that the Nd–Fe–B melt-spun ribbons had the amorphous structure regardless of the boron content. EXAFS studies of the local structure around the Nd atom confirmed that the Nd–Fe–B melt-spun alloys had the amorphous structure and virtually the same nearest neighbor distance from the Nd atom. The amorphous alloys were heated by a differential scanning calorimetry in order to investigate the variation in the local structure during the crystallization process by EXAFS measurements. Although no appreciable difference was found in the nearest neighbor distance of the Nd atom between the amorphous alloys and the crystallized alloys, the small variation in the nearest neighbor distance during the crystallization process was detected by EXAFS measurements.

scholarly journals Inverse Design of Fe-Based Bulk Metallic Glasses Using Machine Learning

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 729
Author(s):  
Junhyub Jeon ◽  
Namhyuk Seo ◽  
Hwi-Jun Kim ◽  
Min-Ha Lee ◽  
Hyun-Kyu Lim ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Metallic Glasses ◽  
Alloy Composition ◽  
Relevant Literature ◽  
Bulk Metallic Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ann Models ◽  
Wide Scale ◽  
Artificial Neural Network Ann

Fe-based bulk metallic glasses (BMGs) are a unique class of materials that are attracting attention in a wide variety of applications owing to their physical properties. Several studies have investigated and designed the relationships between alloy composition and thermal properties of BMGs using an artificial neural network (ANN). The limitation of the wide-scale use of these models is that the required composition is yet to be found despite numerous case studies. To address this issue, we trained an ANN to design Fe-based BMGs that predict the thermal properties. Models were trained using only the composition of the alloy as input and were created from a database of more than 150 experimental data of Fe-based BMGs from relevant literature. We adopted these ANN models to design BMGs with thermal properties to satisfy the intended purpose using particle swarm optimization. A melt spinner was employed to fabricate the designed alloys. X-ray diffraction and differential thermal analysis tests were used to evaluate the specimens.

scholarly journals The Structural Stability of Soft Magnetic Fe-Co-Zr-W-B Metallic Glasses Investigated by the in-situ X-ray Diffraction

2014 ◽  
Vol 126 (1) ◽  
pp. 66-67
Author(s):  
S. Michalik ◽  
J. Bednarcik ◽  
P. Pawlik ◽  
R. Matija ◽  
P. Sovak
Keyword(s):  
Structural Stability ◽  
Metallic Glasses ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray

scholarly journals Anomaly Detection Based on Local Nearest Neighbor Distance Descriptor in Crowded Scenes

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Xing Hu ◽  
Shiqiang Hu ◽  
Xiaoyu Zhang ◽  
Huanlong Zhang ◽  
Lingkun Luo
Keyword(s):  
Anomaly Detection ◽  
Nearest Neighbor ◽  
Computation Time ◽  
Compact Representation ◽  
Feature Descriptor ◽  
Neighbor Distance ◽  
Low Level ◽  
Feature Descriptors ◽  
Nearest Neighbor Distance ◽  
Crowded Scenes

We propose a novel local nearest neighbor distance (LNND) descriptor for anomaly detection in crowded scenes. Comparing with the commonly used low-level feature descriptors in previous works, LNND descriptor has two major advantages. First, LNND descriptor efficiently incorporates spatial and temporal contextual information around the video event that is important for detecting anomalous interaction among multiple events, while most existing feature descriptors only contain the information of single event. Second, LNND descriptor is a compact representation and its dimensionality is typically much lower than the low-level feature descriptor. Therefore, not only the computation time and storage requirement can be accordingly saved by using LNND descriptor for the anomaly detection method with offline training fashion, but also the negative aspects caused by using high-dimensional feature descriptor can be avoided. We validate the effectiveness of LNND descriptor by conducting extensive experiments on different benchmark datasets. Experimental results show the promising performance of LNND-based method against the state-of-the-art methods. It is worthwhile to notice that the LNND-based approach requires less intermediate processing steps without any subsequent processing such as smoothing but achieves comparable event better performance.

Hydrogen absorption in CuTi metallic glasses. I. X-ray diffraction measurements

1985 ◽  
Vol 15 (10) ◽  
pp. 2069-2083 ◽  
Author(s):  
B Grzeta ◽  
K Dini ◽  
N Cowlam ◽  
H A Davies
Keyword(s):  
Metallic Glasses ◽  
Hydrogen Absorption ◽  
X Ray Diffraction ◽  
X Ray
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