Search results for "passiv"

Recent advances in using Photocurrent Spectroscopy for the Characterization of Passive Films on Metals and Metallic Alloys

2020

La Spettroscopia a Fotocorrente (PCS) viene qui presentata come tecnica d’indagine non distruttiva, utile per lo studio delle proprietà elettroniche di film passivi accresciuti su metalli e leghe metalliche. In questo lavoro sono stati studiati tramite PCS film passivi di acciai inossidabili quali AISI 304L, AISI 316L e Duplex 2507, accresciuti in soluzione 0.25 M di NaOH a 82°C, condizione simulante l’ambiente aggressivo tipico di operazioni di pulizia nell’industria del food and beverage. Il band gap dei film passivi cambia notevolmente dopo l’immersione per gli acciai 304L e 316L, con un arricchimento in Fe dei film passivi durante il trattamento. Per l’acciaio Duplex invece, il film pas…

Marqueurs d'une structuration extensive jurassique en arrière de la marge nord-téthysienne (monts du Mâconnais, Bourgogne, France)

2000

Structural analysis of extensional faults in the Mâconnais Hills shows that low-intensity extensional phenomena occurred back from the passive margin of the Ligurian Tethys, the axis of which lay some 400 km southeast of the study area in Mid-Jurassic times. Storm-induced rip current directions and coral lens positions suggest that the palaeotopography was maintained by early faulting.

Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy

1999

Abstract Stratigraphic studies and facies analysis integrated with a new geological and structural survey of the Meso-Cenozoic units outcropping in the Campania–Lucania Apennines, southern Italy, allowed us to restore the palaeogeographic pattern and the tectonic evolution of the chain during Oligo-Miocene times. The southern Apennines are a N150°-striking and NE-verging fold-and-thrust belt mainly derived from the deformation of the African–Apulian passive margin. Four wide belts with different features have been recognized in the chain area. From east to west the following units outcrop: (a) successions characterized by basinal to marginal facies, ranging in age from Cretaceous to Miocene…

Evolution tectonique méso-cénozoïque du bassin de Paris: contraintes stratigraphiques 3D

2000

Abstract 3D stratigraphic geometries of the intracratonic Meso-Cenozoic Paris Basin were obtained by sequence stratigraphic correlations of around 1 100 wells (well-logs). The basin records the major tectonic events of the western part of the Eurasian Plate, i.e. opening and closure of the Tethys and opening of the Atlantic. From earlier Triassic to Late Jurassic, the Paris Basin was a broad subsiding area in an extensional framework, with a larger size than the present-day basin. During the Aalenian time, the subsidence pattern changes drastically (early stage of the central Atlantic opening). Further steps of the opening of the Ligurian Tethys (base Hettangian, late Pliensbachian;...) and…

Assessment of exposure to environmental tobacco smoke in young adolescents following implementation of smoke-free policy in Italy.

2009

We investigated acute and chronic exposure to environmental tobacco smoke (ETS) in a cohort of young adolescents using urinary cotinine and hair nicotine testing after recent implementation of Italian smoke free legislation. Study subjects were 372 Italian young adolescents, between 10 and 16 years of age from the principal city of Sicily, Palermo. Urine and hair samples were collected between November 2005 and May 2006, when the legislation to ban smoking in all the enclosed places of employment (including bars, restaurants, pubs) was completely enforced. An exhaustive questionnaire including sociodemographic characteristics and active and passive exposure to cigarette smoking was complete…

Die passivischen Ausdrücke der medizinischen Fachsprache

1998

Growth of passive layers on nickel during their voltammetric anodic dissolution in a weakly acid medium

2006

Abstract Quartz crystal microbalance in combination with voltammetry has been used for studying the electrochemical oxidation behaviour of a nickel deposit in a weakly acid medium. The instantaneous mass/charge ratio (Fdm/dQ) analysis allows to obtain the fraction of charge consumed in the passivation process, and, that way, the experimental kinetic equation of the passive layer growth. This experimental law has been fitted to the theoretical equation derived from the point defect model theory under voltammetric conditions.

Characteristic Excitation Wavelength Dependence of Fluorescence Emissions in Carbon "quantum" Dots

2017

Carbon "quantum" dots (CDots), generally defined as small carbon nanoparticles with various surface passivation schemes, have emerged to represent a rapidly advancing and expanding research field. CDots are known for their bright and colorful fluorescence emissions, where the colorfulness is associated with the emissions being excitation wavelength dependent. In this work, CDots with 2,2′-(ethylenedioxy)bis(ethylamine) (EDA) for surface functionalization were studied systematically by using steady-state and time-resolved fluorescence methods. The observed fluorescence quantum yields are strongly excitation wavelength dependent, and the dependence apparently tracks closely the observed absor…

Surface passivation of gallium selenide by nitrogen implantation

2002

In this paper we report on the characterization of nitrogen-implanted single-crystal GaSe samples. Nitrogen atoms were implanted at 80 keV, with doses ranging from 4 × 10 13 to 10 15 N + ions cm -2 . Next, samples were aged in open air and characterized by small-area XPS, together with an unimplanted clean surface, in order to quantify the effects of the nitrogen implantation. In general, we found that the oxidation was fully prevented in N + -implanted samples.

Chloride role in the surface of nickel electrode

1998

The chloride ion participation in the dissolution process on nickel electrodes in acid media as well as in the formation of the passive layer and in the pitting corrosion induction were studied. Composite electrodes containing nickel powder dispersed in a polymeric matrix show similar processes to those observed in polycrystalline nickel. Furthermore, phenformine hydrochloride inhibits the dissolution process due to the adsorption of the organic cation on the metal surface, although it does not protect the metal from pitting corrosion. Electrochemical impedance spectroscopy data allowed us to propose a physical model for the role of chloride ion in the dissolution and passivation processes …