Search results for "Applied Physics"
showing 10 items of 1226 documents
Deposition of hollow sphere In2O3 coatings by liquid flame spray
2019
Hollow sphere In(OH)3 coatings were deposited by a simple liquid flame spray with hollow sphere In(OH)3 suspension, which was synthesized by improved soft template methods. The morphology of the In...
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.
B-Scan image analysis for position and shape defect definition in plates
2016
Definition of size, shape and location of defects into a mechanical component is of extreme importance in the manufacturing industry in general and particularly in high-tech applications, and in applications that can become dangerous due to the structural failure of mechanical components. In this paper, a laser-UT system has been used to define position and shape of internal defects in aluminum plates. An infrared pulsed laser is used to generate ultrasonic waves in a point of the plate and a CW laser interferometer is used as receiver to acquire the out-of-plane displacements due to the ultrasonic waves in another point of the plate. The method consists of acquiring a B-Scan map on which s…
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.
Morphological and magnetic analysis of Fe nanostructures on W(110) by using scanning tunneling microscopy and Lorentz microscopy
2016
Abstract We investigated morphological features and magnetic properties of epitaxial Fe nanostructures (films, stripes and nanoparticles) on a W(110) surface with monoatomic steps preferentially along the direction. The nanostructures were prepared in ultra-high vacuum by using electron-beam evaporation and subsequent annealing at different temperatures. Scanning tunneling microscopy measurements in-situ revealed elongated Fe nanostructures with aspect ratios of up to . The observable shape and orientation (along or perpendicular to the monoatomic steps of the substrate) of the nanostructures depended substantially on the preparation parameters. By capping the system with 7 monolayers of Pt…
Molecular dynamics simulations of nanometric metallic multilayers: Reactivity of the Ni-Al system
2011
The reactivity of a layered Ni-Al-Ni system is studied by means of molecular dynamics simulations, using an embedded-atom method type potential. The system, made of an fcc-Al layer embedded in fcc-Ni, is initially thermalized at the fixed temperature of 600 K. The early interdiffusion of Ni and Al at interfaces is followed by the massive diffusion of Ni in the Al layer and by the spontaneous phase formation of $B2$-NiAl. The solid-state reaction is associated with a rapid system heating, which further enhances the diffusion processes. For longer times, the system may partly lose some its $B2$-NiAl microstructure in favor of the formation of $L{1}_{2}$-${\mathrm{Ni}}_{3}\mathrm{Al}$. This st…
Mechanical characterisation of pentagonal gold nanowires in three different test configurations: A comparative study.
2019
Abstract Mechanical characterisation of individual nanostructures is a challenging task and can greatly benefit from the utilisation of several alternative approaches to increase the reliability of results. In the present work, we have measured and compared the elastic modulus of five-fold twinned gold nanowires (NWs) with atomic force microscopy (AFM) indentation in three different test configurations: three-point bending with fixed ends, three-point bending with free ends and cantilevered-beam bending. The free-ends condition was realized by introducing a novel approach where the NW is placed diagonally inside an inverted pyramid chemically etched in a silicon wafer. In addition, all thre…
An investigation into the fracture behaviour of honeycombs with density gradients
2020
International audience; In this study we perform an experimental and computational investigation about the fracture behaviour of polymer honeycombs presenting gradients in terms of lattice density. Such lattice relative density variations are introduced with the aim of mimicking the micro-morphology encountered in some natural materials, such as several kinds of woods, which seems related to the ability of the corresponding macro-material to delay the propagation of fracture under certain conditions. Starting from the conclusions of previous computational analyses, we perform a few experimental tensile tests on ABS model honeycombs obtained by additive manufacturing, with the aim of getting…
Interaction of carbon with microstructural defects in a W-Re matrix: An ab initio assessment
2019
The interaction of carbon atoms with point defects and the core of edge and screw dislocations with Burgers vector a 0 / 2 ⟨ 111 ⟩ in W and a W-Re matrix is studied by means of ab initio calculations. The structure and energetics of the ground-state atomic configurations are presented and rationalized. It is found that di-vacancies, which are thermally unstable in pure W according to the state-of-the-art ab initio calculations, can nucleate at C and Re-C complexes, which fill the gap in the explanation of the emergence of nanovoids observed experimentally under irradiation. Also, on the basis of the recent experimental evidence and our calculations, the temperature ranges for the manifestat…
Performance evaluation and stability of silicide-based thermoelectric modules
2020
Abstract Long-term studies on thermoelectric generators based on N-type magnesium silicide (Mg2.01Si0.49Sn0.5Sb0.01) and P-type higher manganese silicide (Mn0.98Mo0.02Si1.73Ge0.02) materials are presented, in the operating temperature range of 200 °C–400 °C. Emphasis is put on the performance and reliability of the current collector configuration, especially on the hot side of the module, and on the thermomechanical stresses that are created during operation and lifetime testing as a result of large temperature gradients experienced across the thermoelectric legs. With silver (Ag) paste as contact material, the long term-stability of the uni-couples was carried out on non-metalized legs and…