Search results for " Elettroni"
showing 10 items of 1073 documents
Rayleigh-instability-driven dewetting of thin Au and Ag films on indium-tin-oxide surface under nanosecond laser irradiations
2013
Investigations have been carried out on laser-beam-induced nanoparticle (NP) formation in thin (5 nm) Au and Ag films on indium-tin-oxide substrate. After the irradiation the films were observed to break-up into NPs through a dewetting mechanism. This mechanism was investigated as a Rayleigh-instability- driven process. In fact, for each used laser fluence, the resulting Au and Ag NPs' mean size and surface-to-surface mean distance were quantified and correlated between them in the framework of the Rayleigh-instability theory showing an excellent agreement. © The Institution of Engineering and Technology 2013.
Defects in III-N LEDs: experimental identification and impact on electro-optical characteristics
2022
III-N light-emitting-diodes (LEDs) are subject of intense investigations, thanks to their high efficiency and great reliability. The quality of the semiconductor material has a significant impact on the electro-optical performance of LEDs: for this reason, a detailed characterization of defect properties and the modeling of the impact of defects on device performance are of fundamental importance. This presentation addresses this issue, by discussing a set of recent case studies on the topic; specifically, we focus on the experimental characterization of defects, and on the modeling of their impact on the electro-optical characteristics of the devices.
Dangerous Effects Induced on Power MOSFETs by Terrestrial Neutrons
2013
This paper investigates the effects that terrestrial neutrons can induce on power MOSFETs when they are biased during their normal working conditions especially in inverters for photovoltaic applications. After a brief review of power MOSFETs failure phenomena caused by neutron irradiation (with emphasis on so called “Single Event Effects” (SEE)), the results of an accelerated test performed with the Am-Be source at the University of Palermo are discussed.
Photoresponse of graphene ruthenium-complex heterostructures
2015
The aim of this study is to understand the photoresponse of a Ruthenium-complex/graphene heterostructure. Early work demonstrated that light detection by graphene field effect devices was enhanced by dropcasting Ruthenium Complex molecules. Here we proposed to fabricate a new class of devices where the Ruthenium-complex molecules are embedded between two layer of CVD monolayer graphene.
EMI Worsening in a SMPS with Non-linear Inductor
2022
This paper is focused on the input current in a Switched Mode Power Supply (SMPS) in which the power inductor is exploited up to the saturation showing a non-linear behaviour. The input current exhibits a distortion due to the non-linearity. The electromagnetic interference (EMI) caused by the ripple at switching frequency, superimposed to the DC value of the input current, requires a suitable design of the input differential mode (DM) filter. The input current is analyzed both in the time and frequency domain for different operating conditions, and it is compared to a SMPS equipped with a traditional linear inductor.
Time domain symmetry parameters analysis for series arc fault detection
2022
This paper presents a feasibility study of exploiting the symmetry of some parameters for series arc fault detection in electrical circuits. The considered parameters are defined in the time domain and they are based on the current signal derivative and the evaluation of cross-correlation between subsequent observation windows. The analysis is carried out for AC systems, starting from an experimental characterization, which has been carried out in accordance with the Standard UL 1699 requirements for "unwanted tripping tests"and "operation inhibition tests"of arc fault circuit interrupters (AFCIs). The results obtained in different load conditions show that the proposed parameters can be us…
Autonomie locali e politiche pubbliche per l’economia digitale
2019
La rivoluzione digitale ha causato in questi anni un significativo disalli- neamento tra chi subisce le conseguenze delle nuove forme economiche e la distribuzione delle responsabilità regolative tra i diversi attori. Il risultato è che le città sono le più colpite dai cambiamenti in atto, ma non sempre hanno strumenti adeguati a fronteggiare le novità e interpretarle secondo i propri bisogni e necessità. A partire da queste premesse, il presente lavoro analizza l’impatto delle tecnologie digitali sul tessuto socio-economico delle città e ragiona sulle contrapposte esigenze di politiche ritagliate sulle spe- cificità locali e, al contempo, di regole omogenee per il mercato. Su questa inelim…
Effect of the Si doping on the properties of AZO/SiC/Si heterojunctions grown by low temperature pulsed laser deposition
2020
Abstract The structural and photoelectrical properties of Al-doped ZnO (AZO)/SiC/p-Si and AZO/SiC/n-Si heterojunctions, fabricated at low temperature by pulsed laser deposition, were investigated by means of a number of techniques. Raman analysis indicates that SiC layers have the cubic 3C-SiC phase, whilst X-ray diffraction measurements show that AZO films exhibit a hexagonal wurtzite structure, highly textured along the c-axis, with average crystallites size of 35.1 nm and lattice parameter c of 0.518 nm. The homogeneous and dense surface morphology observed by scanning electron microscopy was confirmed by atomic force microscopy images. Moreover, UV–Vis-NIR spectra indicated a high trans…
Physiological parameters measurements in a cardiac cycle via a combo PPG-ECG system
2015
In this paper, we present an innovative way to measure some physiological parameters (such as the pre-ejection period, the pulse transit time, the blood pressure) in a cardiac cycle. A combo PPG-ECG system has been developed and employed to extract both the ECG signal from standard limb leads and simultaneously the photoplethysmography signal from the wrist and the forearm, to calculate the pre-ejection period. This system represents an easy and non-invasive technique to determine these biomedical parameters without using expensive impedance cardiography equipment.
Computationally Efficient Innovative Techniques for the Design-Oriented Simulation of Free-Running and Driven Microwave Oscillators
2014
Analysis techniques for injection-locked oscillators/amplifiers (ILO) can be broadly divided into two classes. To the first class belong methods with a strong and rigorous theoretical basis, that can be applied to rather general circuits/systems but which are very cumbersome and/or time-consuming to apply. To the second class belong methods which are very simple and fast to apply, but either lack of validity/accuracy or are applicable only to very simple or particular cases. In this thesis, a novel method is proposed which aims at combining the rigorousness and broad applicability characterizing the first class of analysis techniques above cited with the simplicity and computational efficie…