Search results for " Physical"
showing 10 items of 20855 documents
Production of Nano-Sized Co<sub>3</sub>O<sub>4</sub> by Pyrolysis of Organic Extracts
2016
The most promising application field of materials based on nano-sized Co3O4 is catalysis. The method of production is one of the factors, which greatly affects the catalytic activity of Co3O4 catalysts. The aim of this research is to study possibilities of a new promising extractive-pyrolytic method (EPM) for the production of Co3O4 nanopowders and silica- and ceria-supported Co3O4 nanocomposites. Solutions of cobalt hexanoate in hexanoic acid and trioctylammonium tetrachlorocobaltate in toluene preliminary produced by solvent extraction were used as precursors. The precursors’ thermal stability, phase composition, morphology and the magnetic properties of the final products of pyrolysis we…
Luminescence of F2 and F3 + centres in LiF crystals irradiated with 12 MeV 12C ions
2018
Dependences of the nanohardness and photoluminescence of F 2 and F 3 + centers on the depth in LiF crystals irradiated with 12 MeV 12 C ions to fluences 10 10 -10 15 ions/cm 2 were studied using laser scanning confocal microscopy, luminescent spectroscopy, and the nanoindentation method. The nanohardness measurements showed a significant hardening effect at the end of the ion run with the dominant contribution of defects formed by the mechanism of elastic collisions. The observed attenuation of the luminescence intensity at high fluences is associated with the intense nucleation of dislocations as traps for aggregate color centers.
Pressure-induced insulator-to-metal transition in α-SnWO4
2016
In-situ high-pressure W L1 and L3 edges x-ray absorption and mid-infrared spectroscopies complemented by first-principles calculations suggest the existence of pressure- induced insulator-to-metal transition in α-SnWO4 in the range of 5-7 GPa. Its origin is explained by a symmetrization of metal-oxygen octahedra due to a strong interaction of Sn 5s, W 5d and O 2p states along the b-axis direction, leading to a collapse of the band gap.
Recent improvements on micro-thermocouple based SThM
2017
The scanning thermal microscope (SThM) has become a versatile tool for local surface temperature mapping or measuring thermal properties of solid materials. In this article, we present recent improvements in a SThM system, based on a micro-wire thermocouple probe associated with a quartz tuning fork for contact strength detection. Some results obtained on an electrothermal micro-hotplate device, operated in active and passive modes, allow demonstrating its performance as a coupled force detection and thermal measurement system.
Space charge behavior of different insulating materials employed in AC and DC cable systems
2017
In this work, the space charge accumulation in three different XLPE based material has been carried out by using the PEA (Pulsed Electro-Acoustic) method. The specimens provided by a cables industry have been subjected to the same DC stress during polarization time at environment temperature. Afterwards, the high voltage generator has been turned off and the amount residual charge has been evaluated. The space charge profiles during polarization and depolarization have been carried out and compared. Finally, the distribution of electric field within the samples has been reported. In particular, the maximum distortion of electric field has been calculated by taking into account the distribut…
First experiments on applying the gasdynamic ECR ion source for negative hydrogen ion production
2017
This article has no abstract. peerReviewed
Application of the reduced I-V Blaesser’s characteristics in predicting PV modules and cells conversion efficiency in medium and high insolation cond…
2017
Abstract The article presents theoretical foundations of application of the reduced I-V Blaesser’s characteristics in predicting a photovoltaic cell/module (PV) efficiency, together with calculation procedures. A detailed analysis of the error of this transformation method of characteristics was carried out. Its practical application in predicting efficiency of operation of various PV cells and modules in medium and high insulation conditions was demonstrated. The practical suitability of the presented method in early detection of ageing phenomena, such as, for example, absorber degradation taking place in PV modules, was demonstrated. The article was prepared on the basis of the results of…
Computational volumetric reconstruction of integral imaging with improved depth resolution considering continuously non-uniform shifting pixels
2018
Abstract In this paper, we propose a new computational volumetric reconstruction technique of three-dimensional (3D) integral imaging for depth resolution enhancement by using non-uniform and integer-valued shifting pixels. In a typical integral imaging system, 3D images can be recorded and visualized using a lenslet array. In previous studies, many computational reconstruction techniques such as computational volumetric reconstruction and pixel of elemental images rearrangement technique (PERT) have been reported. However, a computational volumetric reconstruction technique has low visual quality and depth resolution because low-resolution elemental images and uniformly distributed shiftin…
Integral-Imaging display from stereo-Kinect capture
2017
In this paper, we propose a new approach in order to improve the quality of microimages and display them onto an integral imaging monitor. Our main proposal is based on the stereo-hybrid 3D camera system. Originally, hybrid camera system has dissimilarity itself. We interpret our method in order to equalize the hybrid sensor's characteristics and 3D data modification strategy. We generate integral image by using synthetic back-projection mapping method. Finally, we project the integral image onto our proposed display system. We illustrate this procedure with some imaging experiments in order to prove an advantage of our approach.
Determination of Core Size Dependency on the EMI Suppression in Cable Ferrites
2020
Electromagnetic Compatibility (EMC) engineering should be approached via the systems approach, considering EMC throughout the design to anticipate possible electromagnetic interferences (EMI) problems. Nevertheless, an EMI source may appear when the designed device is supplied via an external power system or it is connected to another device to communicate to it. In these both cases, the cables or interfaces that interconnect the systems could represent the EMI source. Thereby, one of the most common techniques for reducing EMI in cables is the application of an EMI suppressor such as sleeve ferrite cores to them. The advantage of this solution is that it does not involve redesign the elect…