Search results for "Annealing"

Structure determination of thin CoFe films by anomalous x-ray diffraction

2012

This work reports on the investigation of structure-property relationships in thin CoFe films grown on MgO. Because of the very similar scattering factors of Fe and Co, it is not possible to distinguish the random A2 (W-type) structure from the ordered B2 (CsCl-type) structure with commonly used x-ray sources. Synchrotron radiation based anomalous x-ray diffraction overcomes this problem. It is shown that as grown thin films and 300 K post annealed films exhibit the A2 structure with a random distribution of Co and Fe. In contrast, films annealed at 400 K adopt the ordered B2 structure.

A comparative study of heterostructured CuO/CuWO4 nanowires and thin films

2017

Authors are grateful to Reinis Ignatans for XRD measurements.

Mechanical and structural characterizations of gamma- and alpha-alumina nanofibers

2015

Abstract We investigate the applicability of alumina nanofibers as a potential reinforcement material in ceramic matrix compounds by comparing the mechanical properties of individual nanofibers before and after annealing at 1400 °C. Mechanical testing is performed inside a scanning electron microscope (SEM), which enables observation in real time of the deformation and fracture of the fibers under loading, thereby providing a close-up inspection of the freshly fractured area in vacuum. Improvement of both the Young's modulus and the breaking strength for annealed nanofibers is demonstrated. Mechanical testing is supplemented with the structural characterization of the fibers before and afte…

Optimization of thermal coefficient of electrical resistivity of Co-Ti-Si thin films due to laser-induced chemical reactions

2001

The CO2 laser induced optimization of the thermal coefficient of electrical resistivity in Co-Ti-Si thin films is realized. The X-ray diffraction studies of the annealed Co- Ti-Si films confirm that the changes of electrical properties are related to forming a small structure of crystalline compounds Ti5Si3 and CoSi2 in an amorphous matrix.

An XRD, TEM and Raman study of experimentally annealed natural monazite

2002

The healing of radiation damage in natural monazite has been experimentally studied in annealing experiments using XRD, TEM, Raman microprobe and cathodoluminescence analysis. The starting material was a chemically homogeneous monazite from a Brazilian pegmatite with a concordant U–Pb age of 474 ± 1 Ma and a U–Th/He age of 479 Ma. The monazite shows nm-scale defects induced by radioactive decay. The Xray pattern of the unheated starting material revealed two distinct monazite ''phases'' A and B with slightly different lattice parameters. Monazite A shows sharp reflections of high amplitudes and slightly expanded lattice parameters (1% in volume) compared to a standard monazite. Phase B exhi…

Isotactic polypropylene solidification under pressure and high cooling rates. A master curve approach

2000

Solidification in industrial processes very often involves flow fields, high thermal gradients and high pressures: the development of a model able to describe the polymer behavior becomes complex. Recently a new equipment has been developed and improved to study the crystallization of polymers when quenched under pressure. An experimental apparatus based on a modified, special injection moulding machine has been employed. Polymer samples can be cooled at a known cooling rate up to 100 °C/s and under a constant pressure up to 40 MPa. Density, Micro Hardness (MH), Wide angle X-ray diffraction (WAXD), and annealing measurements were then used to characterize the obtained sample morphology. Res…

1975

The density of crystals of poly(ethylene terephthalate), (PETP), Qc is checked by X-ray diffraction assuming a triclinic unit cell and the indices of reflections as found by Bunn. The following unit cell dimensions are found: a = 4,48A, b = 5,85A, c = 10,75 A, α = 99,5°, β = 118,4°, and γ = 111,2°. This gives the density Qc as 1,515g/cm3 which is about 4% higher than that reported by Bunn. Negligible differences in spacings for samples annealed at different temperatures (120°C–260°C) have been found. Only for an annealing temperature of 100°C the higher d-values lead to Qc = 1,484g/cm3. For undrawn PETP films annealed at 250°C the same value of Qc as for drawn PETP was obtained on the basis…

Optimization of impurity profile for p-n junction in heterostructures

2005

We analyze the dopant diffusion in p-n-junction in heterostructure, by solving the diffusion equation with space-varying diffusion coefficient. For a step-wise spatial distribution we find the optimum annealing time to decrease the p-n-junction thickness and to increase the homogeneity of impurity concentration in p or n regions.

Kinetics of dimer F2 type center annealing in MgF2 crystals

2018

Authors are greatly indebted to V. Lisitsyn, A. Ch. Lushchik and R.Vila for stimulating discussions. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement number 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The calculations were performed using facilities of the Stuttgart Supercomputer Center (project DEFTD 12939).

Quantum Random Walks – New Method for Designing Quantum Algorithms

2008

Quantum walks are quantum counterparts of random walks. In the last 5 years, they have become one of main methods of designing quantum algorithms. Quantum walk based algorithms include element distinctness, spatial search, quantum speedup of Markov chains, evaluation of Boolean formulas and search on "glued trees" graph. In this talk, I will describe the quantum walk method for designing search algorithms and show several of its applications.