Search results for "ELECTRICITY"
showing 10 items of 1225 documents
NEUTRON IRRADIATION EFFECTS IN PZ and PZT THIN FILMS
2005
ABSTRACT Neutron irradiation effects on highly oriented antiferroelectric PbZrO3 (PZ) and ferroelectric PbZr0.53Ti0.47O3 (PZT) thin films are investigated in view of their possible application as a temperature sensitive element in a new bolometer system for fusion devices like ITER. All investigated thin films were prepared by a sol-gel technique and by pulsed laser deposition (PLD) respectively. The dielectric properties were investigated in a frequency range from 1 to 250 kHz and at temperatures up to 400°C, prior to and after irradiation to a neutron fluence of 3 * 1022 m−2 (E > 0.1 MeV). After irradiation, the films were anneald in several steps up to 400°C in order to remove the radiat…
Combined heat and power generation with a HCPV system at 2000 suns
2015
In the framework of the FAE “Fotovoltaico ad Alta Efficienza” (“High Efficiency Photovoltaic”) Research Project funded by the Sicilian Region under the program PO FESR Sicilia 2007/2013 4.1.1.1, we have developed an innovative solar CHP system for the combined production of heat and power at the high concentration level of 2000 suns [1]. This work shows the experimental results obtained on FAE-HCPV modules and analyses the behaviour of the system. The solar radiation is concentrated on commercial InGaP/InGaAs/Ge triple-junction solar cells designed for intensive work. The primary optics is a rectangular off-axis parabolic mirror (with a size of 46x46 = 2116 cm2 in a projection normal to the…
An all-organic steroid–D–π-A modular design drives ferroelectricity in supramolecular solids and nano-architectures at RT
2011
Confluence of a modular design approach and self-assembly with a 'steroid-D-π-A' module generates spontaneous polarization in solids and for the first time in nano-architectures constituted from organogels, at room temperature (RT).
Electroelastic Analysis of Piezoelectric Composite Laminates by Boundary Integral Equations
2004
A boundary integral representation for the electroelastic state in piezoelectric composite laminates subjected to axial extension, bending, torsion, shear/bending, and electric loadings is proposed. The governing equations are presented in terms of electromechanical generalized variables by the use of a suitable matrix notation. Thus, the three-dimensional electroelasticity solution for piezoelectric composite laminates is generated from a set of two partially coupled differential equations defined on the cross section of each individual ply within the laminate. These ply equations are linked through the interface conditions, which allow restoration of the model of the laminate as a whole. …
Structural characterization of relaxor ferroelectric PbMg 1/3 Nb 2/3 O 3 -PbTiO 3 thin film heterostructures deposited by pulsed laser ablation
2000
Highly oriented and epitaxial films of relaxor ferroelectric PbMg1/3Nb2/3O3-PbTiO3 (PMN-PT) with a composition (68/32) near the morphotropic phase boundary were deposited by pulsed laser ablation on La0.5Sr0.5CoO3 bottom electrodes, deposited on MgO (100) and LaAlO3 (100). The formation of crystalline phases, epitaxy, film–electrode–substrate orientation relationships and crystal perfection were studied by X-ray diffraction and scanning electron microscopy. The structural properties were found to depend on the deposition conditions and substrate. Correlation of both the dielectric and relaxor properties in the heterostructures and the structural properties of the PMN-PT films was observed.
Revisiting the electronic properties of Molecular Semiconductor – Doped Insulator (MSDI) heterojunctions through impedance and chemosensing studies
2015
Abstract The core activity of this work was to give a new interpretation of the electronic behavior of Molecular Semiconductor – Doped Insulator heterojunctions (MSDI), a new organic device combining two molecular materials with very different electronic properties. We focused on understanding the phenomenon occurring at the interface of fluorinated and non-fluorinated phthalocyanines that appears to be a determining factor for the electronic charge transport in the two-component thin film and ultimately deciding the nature of gas sensing, as illustrated with ozone and ammonia chosen as examples of accepting and donating gases. The impedance measurements showed that the Schottky contact bet…
Thermal imaging in artificial nonlinear media
1997
A method has been developed to determine the temperature distribution of ferroelectric surfaces and volumes. Based on the nonlinear optical effect of second harmonic generation (SHG) in highly nonlinear ferroelectric coating, demonstration of 2D thermosensing has been performed in the wide temperature range (77 K - 600 K). Physical concept of SHG thermal imaging, design of thermosensitive coating and experimental verification of the method has been discussed.
Low Cost Electrical Current Sensors with Extremely Wide Measurement Range
2015
A new electrical current measurement system is presented. It features the ability to dynamically and automatically change its measurement range to the sensed current amplitude without user action. It also exhibits galvanic isolation and near zero insertion loss characteristics.
Molecular Semiconductors — Doped Insulator (MSDI) heterojunctions as new conductometric devices for chemosensing in wet atmosphere.
2015
Most of the gas sensors are based on resistors with inorganic materials and more rarely on other conductometric devices (diodes or transistors). Conductometric sensors have also been designed with molecular materials. Thus, in 2009, Molecular Semiconductor — Doped-insulator (MSDI) heterojunctions were built around a heterojunction between a molecular semiconductor (MS) and a doped-insulator (DI). The MS must be more conductive than the sublayer to take advantage of the heterojunction. The MS is generally of p-type and DI can be of p-type (p-MSDI) or n-type (n-MSDI) material. The energy barrier at the interface depends on the difference in the charge carrier density in the two layers, leadin…
Surface Periodic Domain Engineering in Congruent Lithium Tantalate Crystals
2006
First experiments with the novel electric field Surface Periodic Poling technique have been carried out on Lithium Tantalate. Optimal poling parameters gave 50:50 mark-to-space ratio in the micron scale with good uniformity and high repeatability.