Search results for "Acte"
showing 10 items of 9295 documents
Low energy nano diffraction (LEND) – A versatile diffraction technique in SEM
2019
Abstract Electron diffraction is a powerful characterization method that is used across different fields and in different instruments. In particular, the power of transmission electron microscopy (TEM) largely relies on the capability to switch between imaging and diffraction mode enabling identification of crystalline phases and in-depth studies of crystal defects, to name only examples. In contrast, while diffraction techniques have found their way into the realm of scanning electron microscopy (SEM) in the form of electron backscatter diffraction and related techniques, on-axis transmission diffraction is still in its infancy. Here we present a simple but versatile setup that enables a ‘…
An anomalous wave formation at the Al/Cu interface during magnetic pulse welding
2020
This paper reports an anomalous wave formation at an Al/Cu bimetallic interface produced by magnetic pulse welding. The mechanism of the anomalous wave formation is investigated using both metallurgical characterization and the interface kinematics. It reveals that the anomalous wave is formed with the combination of the intermediate zone and the interdiffusion zone with a thickness of 70 nm, wherein the intermediate zone is caused by the local melting due to the high shear instability, and the interdiffusion zone is formed below the melting point of aluminum combined with ultrahigh heating and cooling rates of about 10^13 °C s^−1. A multiphysics simulation of impact welding has been perfor…
Co-Deposition and Characterization of Hydroxyapatite-Chitosan and Hydroxyapatite-Polyvinylacetate Coatings on 304 SS for Biomedical Devices
2019
During the last decades, biomaterials have been deeply studied to perform and improve coatings for biomedical devices. Metallic materials, especially in the orthopedic field, represent the most common material used for different type of devices thanks to their good mechanical properties. Nevertheless, low/medium resistance to corrosion and low osteointegration ability characterizes these materials. To overcome these problems, the use of biocoatings on metals substrate is largely diffused. In fact, biocoatings have a key role to confer biocompatibility properties, to inhibit corrosion and thus improve the lifetime of implanted devices. In this work, the attention was focused on Hydroxyapatit…
Preparation and Characterization of Nanocrystalline Gadolinium Oxide Powders and Films
2020
Due to its magnetic, electrical, absorption, and emission properties, nanoscale gadolinium oxide is widely used in various fields. In this research, nanocrystalline Gd2O3 powders and films on glass substrates have been produced by the extraction-pyrolytic method. X-ray diffraction analysis revealed the formation of single phase Gd2O3 with cubic crystal structure and the mean crystallite size from 9 to 25 nm in all produced materials. The morphology of samples has been characterized by scanning electron microscopy and transmission electron microscopy.
Nanoporous characterization of modified humidity-sensitive MgO-Al 2 O 3 ceramics by positron annihilation lifetime spectroscopy method
2019
The work was supported by the Ukrainian Ministry of Education and Science. H. Klym thanks Prof. O. Shpotyuk for the fruitful discussion.
Positron annihilation characterization of free volume in microand macro-modified Cu0.4Co0.4Ni0.4Mn1.8O4ceramics
2016
Free volume and pore size distribution size in functional micro and macro-micro-modified Cu0.4Co0.4Ni0.4Mn1.8O4 ceramics are characterized by positron annihilation lifetime spectroscopy in comparison with Hg-porosimetry and scanning electron microscopy technique. Positron annihilation results are interpreted in terms of model implication positron trapping and ortho-positronium decaying. It is shown that free volume of positron traps are the same type for macro and micro modified Cu0.4Co0.4Ni0.4Mn1.8O4 ceramics. Classic Tao-Eldrup model in spherical approximation is used to calculation of the size of nanopores smaller than 2 nm using the ortho-positronium lifetime.
Study of the Secondary Electron Yield in Dielectrics Using Equivalent Circuital Models
2018
[EN] Secondary electron emission has an important role on the triggering of the multipactor effect; therefore, its study and characterization are essential in radio-frequency waveguide applications. In this paper, we propose a theoretical model, based on equivalent circuit models, to properly understand charging and discharging processes that occur in dielectric samples under electron irradiation for secondary electron emission characterization. Experimental results obtained for Pt, Si, GaS, and Teflon samples are presented to verify the accuracy of the proposed model. Good agreement between theory and experiments has been found.
Processing, basic characterization and standard dielectric measurements on PLZT x/65/35 (2≤x≤13) ceramics
2016
ABSTRACTThe influence of external stress (0-800bar) on the dielectric properties of PLZT x/65/35 (2≤x≤13) ceramics was investigated. Applying uniaxial pressure leads to a change in the peak intensity of the electric permittivity (ϵ), of its frequency dispersion as well as in the dielectric hysteresis. The peak intensity of ϵ becomes broader and shifts to lower temperatures for PLZT x/65/35 with x = 2, 4, 6, 7, 9.75, 10, 11 and 13, with increasing pressure, on heating. It was concluded that applying uniaxial pressure induces an increase of Tm, and thus has similar effects as the increase of the Ti ion concentration in the PZT system. Results based on nanoregion switching processes under comb…
Influence of “Productive” Impurities (Cd, Na, O) on the Properties of the Cu 2 ZnSnS 4 Absorber of Model Solar Cells
2021
The research has been supported by grant of the Ministry of Education and Science of the Republic of Kazakhstan AP09562784. The authors (D. Sergeyev) acknowledges the provision of SCAPS-1D software by Prof. Marc Burgelman. The research of A.I. Popov has been supported by the Institute of Solid State Physics (ISSP), University of Latvia (UL). ISSP UL as the Centre of Excellence is supported through the Framework Program for Euro-pean Universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-TeamingPhase2 under Grant Agreement No. 739508, CAMART2 project.
Space‐vector state dynamic model of SynRM considering self‐ and cross‐saturation and related parameter identification
2020
This study proposes a state formulation of the space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) considering both saturation and cross-saturation effects. The proposed model adopts the stator currents as state variables and has been theoretically developed in both the rotor and stator reference frames. The proposed magnetic model is based on a flux versus current approach and relies on the knowledge of 11 parameters. Starting from the definition of a suitable co-energy variation function, new flux versus current functions have been initially developed, based on the hyperbolic functions and, consequently, the static and dynamic inductance versus current functions have be…