990 research outputs found
Epitaxial thin films oxides on Fe: what happens when a low dimensional oxide grows on a highly reactive metal substrate?
No full textThe investigation of oxide films with a thickness of a few nanometers or below grown on another substrate is a scientific topic that has recently attracted a huge amount of experimental and theoretical research work [1].
In this contribution we shall focus on some of the recent advances in understanding the formation of transition metal oxide/Fe interfaces [2,3]. Fe can be considered on the one hand as a prototypical example of ferromagnetic material, and on the other hand as an example of a highly reactive metal. The former characteristic makes it particularly appealing for spintronic applications and magnetic storage media, while the latter makes the preparation of well-defined oxide/metal interfaces a difficult task. For this reason, despite the large body of literature focusing on the preparation and characterization of ultra-thin oxide films on inert materials such as noble and quasi noble metals, comparatively little is known about the atomic scale mechanisms driving the formation of the transition metal oxide/Fe interfaces.
In the first part of the talk we shall discuss the stabilization of single-layer-thick oxide films on Fe, by using selected examples involving the deposition of transition metals on the well-ordered and defect-free Fe(001)-p(1 × 1)O surface. This is characterized by one oxygen atom per surface unit cell which can be used as a reservoir for the stabilization and investigation of Fe-supported twodimensional transition metal oxides [4,5], avoiding at the same time the Fe oxidation occurring when more traditional preparation procedures (such as for instance metal deposition in a reactive oxygen atmosphere) are employed.
In the second part we shall discuss the growth of oxide films out of the interfacial layer, with particular emphasis on the growth mode leading at the same time to sharp interfaces, useful to correctly modeling the interfacial physical phenomena, and atomically flat surfaces, crucial to allow scanning probe microscopy studies down to the atomic scale.
References: [1] See e.g. S.Valeri and G. Pacchioni, eds., Oxide Ultrathin Films (Wiley-VCH Verlag, Weinheim,2011).
[2] M. Finazzi, L. Duò, and F. Ciccacci, Surf. Sci. Rep. 64, 139 (2009).
[3] M. Finazzi, L. Duò, and F. Ciccacci, eds., Magnetic Properties of Antiferromagnetic Oxide Materials: Surfaces, Interfaces and Thin Films (Wiley-VCH Verlag, Weinheim, 2010).
[4] A. Picone, G. Bussetti, M. Riva, A. Calloni, A. Brambilla, L. Duò, F. Ciccacci, and M. Finazzi, Phys. Rev. B 86, 075465 (2012).
[5] A. Picone, G. Fratesi, M. Riva, G. Bussetti, A. Calloni, A. Brambilla, M.I. Trioni, L. Duò, F. Ciccacci, M. Finazzi, Phys. Rev. B 87 (2013) 085403
Ancora alcune riflessioni sul rapporto fra amicizia e diritto nell'antica Roma
No full textNel contributo sono studiati alcuni testi letterari utili per precisare aspetti particolari del rapporto fra amicizia e diritto nella rappresentazione dei romani nella repubblica e agli inizi del principat
The dynamic coregionalization model in air quality risk assessment
No full textOne major role of environment agencies is to provide concise indicators about a country's air quality and its impact on population health. On the one hand, such environmental indicators must be easily understood by the public and on the other, they should be useful to compare air quality over different years. Indeed, it is important to assess whether any actions undertaken to improve air quality have been successful or not (Scott, 2007).
When the sets of airborne pollutants measured at different monitoring sites are different, it is not always clear how to define daily and yearly indicators for the whole country or how to evaluate their uncertainty. Moreover, it is not straightforward to compare across years when in each year, the structure of the monitoring network (sites included), the quantity of missing data and meteorological conditions differ.
In order to define a sound statistical framework within which to address the above issues, the dynamic coregionalization model introduced by Fassò and Finazzi (2010 and 2011) is considered. Based on temporal and spatial latent variables, the model is a multivariate hierarchical space-time model able to cope with missing data and with data coming from heterogeneous monitoring networks, where different pollutants may be measured at different sites.
When only the temporal latent variable is considered, the model can be used to derive a daily air quality indicator for the entire region of interest. If different pollutants have different impacts on population health, then a weighted indicator can be evaluated. When a set of covariates and the latent spatial variable are also included, the model can provide either daily or yearly average concentration maps for the pollutants considered.
By applying non-parametric bootstrap techniques, quantities such as the probability that a pollutant exceeds a threshold level L over a period of time at a particular point in space, the expected number of days that L has been exceeded during the year and the probability that L has been exceeded for at least N days can be evaluated. These results can then be related to population figures in order to assess population exposure and risk. This approach is illustrated using Scottish air quality data for 6 pollutants for the year 2009
Le definizioni romane dell'obbligazione
No full textLe definizioni romane dell'obbligazioneRoman definitions of the obligatio
Il “sus balteatus” e la bolgia che «assanna»: animali e retorica in Dante
No full textIl contributo indaga alcuni loci danteschi in cui procedimenti retorici dal peculiare statuto transuntivo (applicazione di topoi metaletterari e concretizzazioni di astratti) si intrecciano con elementi figurativi tratti dal mondo animale. L’analisi si concentra dapprima sulla riflessione dedicata al principio della "convenientia" e al concetto di "discretio" di De vulg. el., II 1, 9, dimostrando lo spiccato retroterra tecnico-teorico dell'immagine del "sus balteatus". La seconda sezione si sofferma sull'impiego traslato del lemma "azzannare" di Inf., XVIII 98-99, che sancisce la parziale zoomorfizzazione della bolgia degli adulatori
«Non è nuova a li orecchi miei tal arra». Una metafora economica in Dante e la sua fortuna medievale
No full textStudio della metafora economica dell'arra in Dante, con escursioni anche in Petrarca e Boccaccio. Ricostruzione delle principali fonti classiche, tardoantiche e medievali alla base del traslato
Acute vs chronic effects of l-dopa on bladder function in patients with mild Parkinson disease
No full textTo compare acute and chronic effects of l-dopa on bladder function in levodopa-naive Parkinson disease (PD) patients who had urinary urgency
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