Search results for "RAMAN"

Nudo femminile. Intervento di conservazione di un dipinto incompleto di Giacomo Manzù

2009

L'opera di Giacomo Manzù (Bergamo 1908- Roma 1991) oggetto di questo lavoro, sebbene incompleta,presenta degli elementi che si possono riscontrare di frequente nell'ambito della produzione pittorica del Maestro. In particolare il dipinto, realizzato con tecnica mista su compensato, ci rimanda, anche per l'impostazione delle figure, ad altre due opere: Donna nuda con sedia, 1958, carbone su legno biacno e Donna con sedia, 1947, carbone matita e tempera. Dietro la tavola è posta inoltre un'etichetta del Gementeemuseum dell'Aia, Olanda, che ha permesso di individuare il titolo, Nudo femminile, e che testimonia la presenza temporanea del dipinto in una mostra allestita presso il museo olandese.…

Nanostructured anatase TiO2 densified at high pressure as advanced visible light photocatalysts

2015

This study reports on characterization and photoactivity of nanostructured TiO2 samples, which have been permanently densified under high pressures, up to 2.1 GPa. Commercial Mirkat 211 anatase has been used as a benchmark sample, in order to investigate the effect of unidirectional high pressure on structural, optical and photocatalytic properties of TiO2. Vibrational Raman spectroscopy shows that the treatment does not cause transitions among the different crystalline phases of titanium dioxide. UV-vis diffuse reflectance spectra reveal that increasing pressure gives rise to a shift of the absorption onset towards higher wavelength enhancing the photoactivity under visible radiation. Samp…

Davide Bramante Rizzuto Arte

2013

Indagini non Distruttive per una Migliore Conoscenza dei Documenti dell'Archivio Storico Diocesano di Palermo

2008

Un soffitto ligneo intagliato miniato del XV secolo in Sicilia. Studio e Indagini Diagnostiche

2009

Incoherent Dispersive Shocks and Spectral Collapse

2014

We predict the existence of incoherent dispersive shock waves and collapse-like singularities that occur in the spectral evolution of incoherent optical waves propagating in a noninstantaneous nonlinear medium.

Spectral long-range interaction of temporal incoherent solitons.

2014

We study the interaction of temporal incoherent solitons sustained by a highly noninstantaneous (Raman-like) nonlinear response. The incoherent solitons exhibit a nonmutual interaction, which can be either attractive or repulsive depending on their relative initial distance. The analysis reveals that incoherent solitons exhibit a long-range interaction in frequency space, which is in contrast with the expected spectral short-range interaction described by the usual approach based on the Raman-like spectral gain curve. Both phenomena of anomalous interaction and spectral long-range behavior of incoherent solitons are described in detail by a long-range Vlasov equation.

Raman spectroscopy study of β-irradiated silica glass

2003

International audience; Natural and synthetic silica glass samples with different OH content have been submitted to β-irradiation at different doses from 106 to 5 × 109 Gy in a Van de Graaff accelerator. Structural changes under irradiation have been analyzed by Raman spectroscopy. The main findings are: (i) a decrease of the Si–O–Si angular dispersion and the average Si–O–Si angle as a function of dose and (ii) an increase of number of three-membered SiO4 ring concentration during irradiation. These results show therefore that purely electronic excitation from β-irradiation induces in a-SiO2 small but significant structural changes of the SiO4 membered ring statistics (size and dispersion)…

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…

Nitrogen interstitial defects in silicon. A quantum mechanical investigation of the structural, electronic and vibrational properties

2019

The vibrational features of eight interstitial nitrogen related defects in silicon have been investigated at the first principles quantum mechanical level by using a periodic supercell approach, a hybrid functionals, an all electron Gaussian type basis set and the Crystal code. The list includes defects that will be indicated as Ni (one N atom forming a bridge between two Si atoms), Ni-Ns (one interstitial and one substitutional N atom linked to the same Si atom), Ni-Ni (two Ni defects linked to the same couple of silicon atoms) and Ni-Sii-Ni (two Ni defects linked to the same interstitial silicon atom). Four 〈0 0 1〉 split interstitial (dumbbell) defects have also been considered, in which …