Search results for "SYSTEMS"
showing 10 items of 11952 documents
Measurements on partial discharge in on‐site operating power transformer: a case study
2018
This study presents the case study of a substation in-service power transformer referred to the on-site partial discharge (PD) detection and evaluation methods. An original methodology for simultaneous application of three methods is proposed: electrical, acoustic and ultra-high frequency. Transformer is powered by the power grid and no external generator is required according to the proposed methodology. Furthermore, several possibilities of applying these concurrent measurements and benefits of such solution in terms of result interpretation, interference resistance and on-site measurement applicability are indicated. The proposed methodology allows for a fast, accurate and secure PD diag…
A General Mathematical Formulation for the Determination of Differential Leakage Factors in Electrical Machines with Symmetrical and Asymmetrical Ful…
2018
This paper presents a simple and general mathematical formulation for the determination of the differential leakage factor for both symmetrical and asymmetrical full and dead-coil windings of electrical machines. The method can be applied to all multiphase windings and considers Gorges polygons in conjunction with masses geometry in order to find an easy and affordable way to compute the differential leakage factor, avoiding the adoption of traditional methods that refer to the Ossanna's infinite series, which has to be obviously truncated under the bound of a predetermined accuracy. Moreover, the method described in this paper allows the easy determination of both the minimum and maximum v…
Guest Editorial
2019
Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²
Effect of Cu doping on Ba0.95Pb0.05TiO3 electrical properties studied by means of electrical impedance spectroscopy
2019
The ceramics of 0.95BaTiO3–0.05PbTiO3+Xwt.%CuO (X = 0.05, 0.1, 1, 3) were prepared by a solid phase reaction. The structural and morphology studies were carried out by means of X-ray diffraction te...
Inhomogeneous electron distribution in InN nanowires: Influence on the optical properties
2012
In this work, we study theoretically and experimentally the influence of the surface electron accumulation on the optical properties of InN nanowires. For this purpose, the photoluminescence and photoluminescence excitation spectra have been measured for a set of self-assembled InN NWs grown under different conditions. The photoluminescence excitation experimental lineshapes have been reproduced by a self-consistent calculation of the absorption in a cylindrical InN nanowires. With the self-consistent model we can explore how the optical absorption depends on nanowires radius and doping concentration. Our model solves the Schrodinger equation for a cylindrical nanowire of infinite length, a…
Enabling partially reconfigurable IP cores parameterisation and integration using MARTE and IP-XACT
2012
International audience; This paper presents a framework which facilitates the parameterization and integration of IP cores into partially reconfigurable SoC platforms, departing from a high-level of abstraction. The approach is based in a Model-Driven Engineering (MDE) methodology, which exploits two widely used standards for Systems-on-Chip specification, MARTE and IP-XACT. The presented work deals with the deployment level of the MDE approach, in which the abstract components of the platform are first linked to the lower level IP-XACT counterparts. At this phase, information for parameterization and integration is readily available, and a synthesizable model can be obtained from the gener…
Effects of Thermal Neutron Irradiation on a Self-Refresh DRAM
2020
International audience; In this study, static and dynamic test methods were used to define the response of a self-refresh DRAM under thermal neutron irradiation. The neutron-induced failures were investigated and characterized by event cross-sections, soft-error rate and bitmaps evaluations, leading to an identification of permanent and temporarily stuck cells, block errors, and single-bit upsets.
Ab initio calculations of CaZrO3, BaZrO3, PbTiO3 and SrTiO3 (001), (011) and (111) surfaces as well as their (001) interfaces
2019
We carried out ab initio calculations for technologically important ABO3 perovskites, like, CaZrO3, BaZrO3, PbTiO3 and SrTiO3, their (001), (011) and (111) surfaces as well as (001) interfaces. For...
Thermal expansion and polarization of (1-x)PNN-xPT solid solutions
2019
The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x = 0-0.8. The anomalous and lattice contributions to deformation and...
Anomalies of dielectric properties and conductivity in single domain LiNbO3:Zn crystals
2016
ABSTRACTA study of the temperature dependence of dielectric constant, conductivity, and piezoelectric modulus in the single-domain state of LiNbO3 crystals modified by Zn admixture at threshold concentration is reported. Unipolarity of the LiNbO3:Zn crystals is observed to increase after treatment of brand-new samples by high-temperature electro-diffusion annealing and by subsequent high-temperature annealing of short-circuited samples. The observed effects are explained as a result of meta-stable residual domains collapsing at high temperature the collapse being assisted by disintegration of charged clusters stabilizing domain walls. The rise of unipolarity is accompanied by anomalies on t…