Search results for "Epos"
showing 10 items of 1649 documents
Sull’espressione non prototipica dell’agentività nei testi siciliani del XIV secolo
2009
L’esistenza di più opzioni lessicali per la codifica dell’agente nelle costruzioni passive dell’italoromanzo è sempre stata assunta come semplice dato di fatto. Tuttavia, un’analisi accurata dei testi rivela l’esistenza di una distribuzione funzionale, che si manifesta in modo coerente, sebbene non identico, nei diversi vernacoli. Sulla base di quest’osservazione, viene formulata e testata l’ipotesi secondo cui tale distribuzione sia semanticamente determinata: essa si motiva nel tipo di rappresentazione dell’evento codificato dalle due preposizioni, che articola in forme diverse la nozione di agentività. Sullo sfondo di un approccio teorico di matrice cognitivista e sulla base di un esame …
Sputtered SiOxNy thin films: improving optical efficiency of liquid crystal diffuser elements in multi-focal near-to-eye display architecture
2021
In this work we present reactive sputtered SiOxNy films with a variable refractive index as a convienent solution for contrast improvement of liquid crystal diffuser multi stacks in near-to-eye AR/VR displays. The focus concerns minimization of light reflections between internal structures, in particular ITO, by optimizing internal layers through tailored properties of thin film coatings, as well as subsequent laser patterning of thin film stack. Inorganic thin films have been deposited on glass by physical vapor deposition. Corresponding refractive index, thickness, uniformity and dielectric characteristics and other electro-optical properties have been measured and their impact on the res…
Structural and in situ vibrational study of luminescent cluster assembled silicon thin films
2006
A Low Energy Cluster Beam Deposition apparatus is employed to produce cluster assembled silicon thin films (1-500 nm thick) by using a laser vaporization source. The generated clusters are studied since their formation through time of flight mass spectra and the calculated size in the gas phase are compared with those of the deposited aggregates obtained through Dynamic Scanning Force Microscopy. The deposited material is also studied "in situ" by Raman and infrared spectroscopy. The spectra reveal that the as deposited clusters are hydrogenated with negligible amount of oxide. A comparison of the film properties before and after their air exposure shows that the exposition induces a consis…
Low-cost high-haze films based on ZnO nanorods for light scattering in thin c-Si solar cells
2015
Light scattering from ZnO nanorods (NR) is investigated, modeled, and applied to a solar cell. ZnO NR (120-1300 nm long, 280-60 nm large), grown by low-cost chemical bath deposition at 90 degrees C, exhibit diffused-to-total transmitted light as high as 70% and 30% in the 400 and 1000 nm wavelength range, respectively. Data and scattering simulation show that ZnO NR length plays a crucial role in light diffusion effect. A transparent ZnO NR film grown on glass and placed on top of a 1 mu m thick c-Si solar cell is shown to enhance the light-current conversion efficiency for wavelengths longer than 600 nm. (C) 2015 AIP Publishing LLC.
Solar blind detectors based on AlGaN grown on sapphire
2005
Solar blind detectors have been fabricated based on AlGaN heterostructures grown on sapphire by molecular beam epitaxy or chemical vapour deposition. MSM and Schottky detectors were investigated. High performance devices have been obtained thanks to an optimization of the material crystalline quality (including the suppression of cracks) and of the process. We show that the spectral limitations of MSM detectors are dictated by intrinsic phenomena that are analysed in details while the responsivity and detectivity also depends on the technological process with a special emphasis on the geometry of finger and contact pads. One and two dimensional arrays have been fabricated and preliminary re…
Surface preparation influence on the initial stages of MOCVD growth of TiO2 thin films
2006
In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS), completed by ex situ atomic force microscopy (AFM) analyses, were performed in order to compare the initial stages of MOCVD growth of TiO 2 thin films on two different surface types. The first type was a silicon native oxide free hydrogen terminated surface and the second one was a silicon dioxide surface corresponding to a thin layer of 3.5 nm thick in situ thermally grown on silicon substrate. Si(100) was used as substrate, and the growths of TiO 2 thin films were achieved with titanium tetraisopropoxide (TTIP) as precursor under a temperature of 675 °C, a pressure of 0.3 Pa and a deposition time of 1 h. Whate…
Modelling sediment delivery processes by a stream tube approach
1999
Abstract The sediment delivery processes due to the travel along a hydraulic path having an uniform slope and to the concave shape of the path are modelled. In particular, using a power equation for modelling the slope profile and RUSLE with two different expressions of the topographic factors, a criterion to define the erosion active slope length, i.e. the slope length in which no deposition processes occur, is initially proposed. Then, the RUSLE equation is adapted to concave profiles by a correction factor of the topographic factors depending on slope curvature. Finally, the deduced relationships (equations (19) and (27)) for correcting the topographic factors for a concave slope are exp…
TCO/Ag/TCO transparent electrodes for solar cells application
2014
Among transparent electrodes, transparent conductive oxides (TCO)/metal/TCO structures can achieve optical and electrical performances comparable to, or better than, single TCO layers and very thin metallic films. In this work, we report on thin multilayers based on aluminum zinc oxide (AZO), indium tin oxide (ITO) and Ag deposited by RF magnetron sputtering on soda lime glass at room temperature. The TCO/Ag/TCO structures with thicknesses of about 50/10/50 nm were deposited with all combinations of AZO and ITO as top and bottom layers. While the electrical conductivity is dominated by the Ag intralayer irrespective of the TCO nature, the optical transmissions show a dependence on the natur…
Mechanisms for Translocation of Heavy Metals from Soil to Epigeal Mosses
2011
The mechanisms for translocation of heavy metals from soil to epigeal mosses were investigated. The first mechanism was demonstrated for (137)Cs and involved the uplifting of the pollutant-containing dust from the soil, followed by the local secondary deposition on surfaces of epigeal mosses and epiphytic lichens. The second mechanism involved the diffusion of metal cations from the soil through water wetting the moss into the gametophyte. The mechanism was demonstrated by measuring the electric conductance of wetted gametophytes with single ends immersed in solutions of Cu and Na salts. In addition, the concentrations of Cu and Cd were compared in moss samples exposed to the natural soil a…
Influence of environmental factors on the spatial distribution and diversity of forest soil in Latvia
2012
This study was carried out to determine the spatial relationships between environmental factors (Quaternary deposits, topographical situation, land cover, forest site types, tree species, soil texture) and soil groups, and their prefix qualifiers (according to the international Food and Agricultural Organization soil classification system World Reference Base for Soil Resources [FAO WRB]). The results show that it is possible to establish relationships between the distribution of environmental factors and soil groups by applying the generalized linear models in data statistical analysis, using the R 2.11.1 software for processing data from 113 sampling plots throughout the forest terri…