Search results for "MOBILITY"
showing 10 items of 922 documents
Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs
2019
GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (R) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (R) characteristic…
DC and 1/f noise characterization of cryogenically cooled pseudomorphic HEMT's
2002
Pseudomorphic (AlGaAs/InGaAs/GaAs) HEMT's have exhibited the best noise performance over the entire LF-to-microwave frequency range if compared to MESFET's and conventional GaAs HEMT's, due to either a reduced flicker noise, a lower G/R contribution and a smaller high-field diffusion noise. We have recently investigated the microwave (up to 18 GHz) noise properties of packaged pseudomorphic HEMT's from 290 K down to cryogenic temperature values. The current experimental work is aimed at extending such analysis to the LF noise range and at low temperatures. Cryogenic noise spectra (1 Hz to 100 KHz) and DC characteristics have therefore been recorded and the relevant observations on the devic…
Impact of contact resistance on the electrical properties of MoS2 transistors at practical operating temperatures
2017
Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance, RC, associated with the Schottky barrier between source/drain metals and MoS2 currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2 FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (μ) an…
TEMPERATURE DEPENDENT NOISY MODELS OF PSEUDOMORPHIC HEMTs
1994
From a complete characterization in terms of noise and scattering parameters carried out at room temperature in the 8–16 GHz frequency range, the noisy small‐signal model of a pseudomotphic HEMT series has been extracted. The transistor scattering parameters have been subsequently measured at lower temperatures (down to −50 °C) by placing the device text fixture in a thermo‐controlled chamber. The model effectiveness has then been tested by determining the circuit element values at the different temperatures and by observing the model noise performance.
Impact of cloud processes on aerosol particle properties: results from two ATR-42 flights in an extended stratocumulus cloud layer during the EUCAARI…
2011
Abstract. Within the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project, the Meteo France research aircraft ATR-42 was operated from Rotterdam airport during May 2008, to perform scientific flights dedicated to the investigation of aerosol-cloud interactions. Therein, the objective of this study is to illustrate the impact of cloud processing on the aerosol particles physical and chemical properties. The presented results are retrieved from measurements during a double-flight mission from Rotterdam (Netherlands) to Newcastle (UK) and back using data measured with compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS) and Scanning Mobility Particle Sizer (SMPS…
Strategie e contro-strategie per una città a misura d’uomo?
2018
Le strategie che da qualche anno vengono messe in campo per “costruire” città sostenibili si confrontano con i temi ambientali declinati in differenti campi. Tra questi, certamente, quello della mobilità riveste un ruolo chiave. Per tale ragione le città da tempo si stanno dotando di Piani per la mobilità sostenibile puntando sul rafforzamento del trasporto pubblico e sulle piste ciclabili. La città di Palermo, nell’ottica di migliorare e integrare i vari sistemi di trasporto, ha redatto diversi progetti di infrastrutture per le piste ciclabili finalizzati a un cambiamento delle abitudine delle persone, con conseguenti benefici ambientali. Questi progetti agiscono fortemente sugli spazi urb…
EMPLOYMENT OF CATIONIC SOLID-LIPID NANOPARTICLES AS RNA CARRIERS
2007
Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. In this article, the suitability of cationically modified solid-lipid nanoparticles (SLN) as a nonviral vector for gene delivery was investigated, in order to obtain stable materials able to condense RNA. Cationic SLN were produced by microemulsion using Compritol ATO 888 as matrix lipid, Pluronic F68 as tenside, and dimethyldioctadecylammonium bromide (DDAB) as cationic lipid. The resulting particles were approximately 100 nm in size and showed a highly positive surface charge (+41 mV) in water. Size and shape were further characterized by scanning electron microscopy (SEM) measurements. M…
Impact of hydrothermal alteration processes on element mobility and potential environmental implications at the Sousaki solfataric field (Corinthia -…
2020
Abstract Samples of efflorescences and encrustations of hydrothermal origin were collected at Sousaki (Greece) and analysed for their mineralogical (XRD) and chemical composition. Solutions obtained both from mineralization with HNO3 and from leaching with deionised water were analysed for major (ICP-OES), minor and trace metals (ICP-MS) and sulfate contents (IC). Results evidence the dependence of the chemical and mineralogical composition on micro-environmental conditions i.e. humidity, oxygen-rich or -poor environment, exposed or sheltered from meteoric agents. In fact, the presence of highly soluble sulfate minerals with elevated contents of many metals (e.g. Mg, Al, Fe, Mn, Cr, Ni, etc…
Natural emotion: progetti di itinerari naturalistici e nuovi accessi al patrimonio archeologico di Tindari
2019
The exceptional orographic and natural conditions, together with the cultural and patrimonial ones, of our territory have become the landscape of relations between the spaces where silence, slowdown and acceleration define the urban and human imagination of the territories of the very different minor centers among them by topographical location, by cultural and linguistic traditions and specificities. What future for the smaller centers? This is one of the questions of the contribution that it intends to face closely the role of the architectural project in the fragile territory of the minor centers where it is possible to find the constants in the critical issues of the participants that c…
La inmigración y el género como factores clave de la movilidad educativa en España
2021
En este trabajo analizamos los determinantes del logro educativo para la población inmigrante en España, así como su grado de movilidad intergeneracional educativa, comparando estos resultados con el resto de residentes en nuestro país. Como fuente de información, utilizamos la encuesta EU-SILC de 2011, que incluye un módulo de transmisión intergeneracional de pobreza. Gracias a este módulo, podemos conocer el nivel académico de los progenitores y compararlo con el alcanzado por sus hijos. Para analizar los determinantes del logro educativo, utilizamos una estimación de máxima verosimilitud, teniendo en cuenta variables del propio individuo, de su familia y de su entorno, mientras que el es…