Search results for "Epos"

Temperature and time dependent electron trapping in Al2O3 thin films onto AlGaN/GaN heterostructures

2022

In this article, the charge trapping phenomena in Al2O3 thin films grown by atomic layer deposition (ALD) on AlGaN/GaN heterostructures have been studied by time-dependent capacitance–voltage (C-V) measurements as a function of temperature. In particular, monitoring the transient of the capacitance enabled us to estimate the maximum depth of the insulating layer interested by the negative charge trapping effect under our bias stress conditions and to determine a charge traps density in the bulk Al2O3 in the order of 3 × 1019 cm−3. A temperature dependent C-V analysis up to 150 °C demonstrated the presence of two competitive mechanisms that rule the electron capture and emission in the Al2O3…

Microtomographic Quantification of Hydraulic Clay Mineral Displacement Effects During a CO2 Sequestration Experiment with Saline Aquifer Sandstone

2013

We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the…

Fossil wood in Middle–Upper Jurassic marine sedimentary cycles of France: relations with climate, sea-level dynamics, and carbonate-platform environm…

1998

Abstract Vegetation, climate, and sea-level oscillations interact in complex ways. Intuition suggests that climatic variations are recorded in geological deposits by both fossil phytoclasts and sediments. Therefore investigation of palaeobotanical remains within a precise sedimentological framework may help to decipher this much-debated interaction. A database of 129 Jurassic (Bathonian–Oxfordian) fossil wood samples from France is used here as a case study. The palaeoenvironment (freshwater swamp, carbonate lagoon, shoreface, argillaceous offshore) and the second-order relative sea-level phases were determined for each datum. There is no correlation between the wood genera distribution and…

One My scale subsidence of carbonate sedimentary bodies and the viscosity of the lower crust

2004

Abstract The possibility of flow of the lower crust under the load produced by carbonate sedimentary accumulations is investigated through the example of the Paris basin during the Middle Jurassic (i.e. Bathonian). Depositional geometries, water depths and sedimentary environments have been estimated and correlated for 164 sites spread over a surface of 380 per 220 km for three successive periods lasting each less than 0.8 My. A signal of relative vertical displacement has been extracted from water-depth and sedimentary thickness. Data have then been interpolated to produce maps of velocity of vertical displacement, sedimentation rate, water depth, and water-depth variation between two peri…

FACIES HETEROGENEITY AND SEDIMENTARY PROCESSES ALONG A TECTONICALLY-CONTROLLED CARBONATE SLOPE: A CASE STUDY FROM THE CRETACEOUS OF WESTERN SICILY (I…

2020

Analysis of Organic Aerosols Using a Micro-Orifice Volatilization Impactor Coupled to an Atmospheric-Pressure Chemical Ionization Mass Spectrometer

2014

We present the development and characterization of a combination of a micro-orifice volatilization impactor (MOVI) and an ion trap mass spectrometer (IT/MS) with an atmospheric-pressure chemical ionization (APCI) source. The MOVI is a multi-jet impactor with 100 nozzles, allowing the collection of aerosol particles by inertial impaction on a deposition plate. The pressure drop behind the nozzles is approximately 5%, resulting in a pressure of 96 kPa on the collection surface for ambient pressures of 101.3 kPa. The cut-point diameter (diameter of 50% collection efficiency) is at 0.13 μm for a sampling flow rate of 10 L min–1. After the collection step, aerosol particles are evaporated by he…

THE SEMANTIC NETWORK OF THE LATIN PREPOSITION PER: A DIACHRONIC INVESTIGATION

2020

Proponiamo qui i risultati di uno studio corpus-based sugli slittamenti diacronici osservabili nel network semantico della preposizione per in latino. Sulla base della Cognitive Grammar, descriviamo la semantica di per situandola lungo un continuum che procede dal concreto all’astratto, a partire da un contenuto schematico originario; discutiamo, quindi, i percorsi attraverso i quali i nuovi significati astratti emergono attraverso sli ttamenti metonimici, focalizzando la nostra attenzione sui ruoli causali e sulla caratteristica di animatezza.

Accounting meets economics: towards an ‘accounting view’ of money.

2018

Questo studio pone le fondamenta dell’ “Approccio Contabile” (“Accounting View”) alla moneta. Sulla base dei principi di Ragioneria Generale riconosciuti internazionalmente, lo studio argomenta che le monete emesse dallo stato e dalla banca centrale non costituiscono debito e che nei regimi di riserva frazionaria soltanto una quota della moneta emessa dalle banche commerciali pu essere considerata quale debito. Lo studio chiarisce come il signoraggio associato all’emissione di queste monete debba essere contabilizzato nei bilanci delle istituzioni emittenti ed esamina le implicazioni di ci`o per la corretta comprensione della moneta. Il nuovo approccio fa luce su argomenti quali la vera nat…

Platinum-doped CeO2 thin film catalysts prepared by magnetron sputtering.

2010

The interaction of Pt with CeO(2) layers was investigated by using photoelectron spectroscopy. The 30 nm thick Pt doped CeO(2) layers were deposited simultaneously by rf-magnetron sputtering on a Si(001) substrate, multiwall carbon nanotubes (CNTs) supported by a carbon diffusion layer of a polymer membrane fuel cell and on CNTs grown on the silicon wafer by the CVD technique. The synchrotron radiation X-ray photoelectron spectra showed the formation of cerium oxide with completely ionized Pt(2+,4+) species, and with the Pt(2+)/Pt(4+) ratio strongly dependent on the substrate. The TEM and XRD study showed the Pt(2+)/Pt(4+) ratio is dependent on the film structure.

Growth and composition of nanostructured and nanoporous cerium oxide thin films on a graphite foil.

2015

The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of the layers with different thicknesses performed by energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and X-ray photoelectron spectroscopy have pointed to the reduction of the cerium oxide layers. In the deposited layers, cerium was present in mixed Ce(3+) and Ce(4+) valence. Ce(3+…