Search results for " surfaces."
showing 10 items of 173 documents
Ulrich bundles on K3 surfaces
2019
We show that any polarized K3 surface supports special Ulrich bundles of rank 2.
On the topology of surfaces with the generalised simple lift property.
2020
In this paper, we study the geometry of surfaces with the generalised simple lift property. This work generalises previous results by Bernstein and Tinaglia, and it is motivated by the fact that leaves of a minimal lamination obtained as a limit of a sequence of properly embedded minimal disks satisfy the generalised simple lift property.
A theoretical study of the gas-phase chemi-ionization reaction between uranium and oxygen atoms
2005
The U+O chemi-ionization reaction has been investigated by quantum chemical methods. Potential-energy curves have been calculated for several electronic states of UO and UO+. Comparison with the available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemi-ionization reaction U+O -> UO++e(-) is proposed. The U+O and Sm+O chemi-ionization reactions are the first two metal-plus-oxidant chemi-ionization reactions to be studied theoretically in this way.
Observation and analysis of Fano-like lineshapes in the Raman spectra of molecules adsorbed at metal interfaces
2015
Surface enhanced Raman spectra from molecules (bipyridyl ethylene) adsorbed on gold dumbells are observed to become increasingly asymmetric (Fano-like) at higher incident light intensity. The electronic temperature (inferred from the anti-Stokes (AS) electronic Raman signal increases at the same time while no vibrational AS scattering is seen. These observations are analyzed by assuming that the molecule-metal coupling contains an intensity dependent contribution (resulting from light-induced charge transfer transitions as well as renormalization of the molecule metal tunneling barrier). We find that interference between vibrational and electronic inelastic scattering routes is possible in …
THE ROLE OF THERMOGRAPHY IN THE NON-DESTRUCTIVE EVALUATION OF HISTORICAL ARCHITECTURAL SURFACES. Some observation about the method and its purpose
2014
Infrared-Thermography (IRT) has become a supporting tool for the investigation of historical structures and facades. Using the non-destructive testing method for the detection can give a profound knowledge about the current status of the object and the state of decay, about different kinds of discontinuities at historical facades, of construction details and of thermal bridges in the facades. Different case studies of thermographic surveys on some Sicilian monuments are presented and discussed to illustrate how the method can offer applicable information about the investigated objects and demonstrate its reasonable integration into conservation projects.
Current-induced domain wall motion in nanoscale ferromagnetic elements
2011
The manipulation of a magnetic domain wall (DW) by a spin polarized current in ferromagnetic nanowires has attracted tremendous interest during the last years due to fundamental questions in the fields of spin dependent transport phenomena and magnetization dynamics but also due to promising applications, such as DW based magnetic memory concepts and logic devices. We comprehensively review recent developments in the field of geometrically confined domain walls and in particular current induced DW dynamics. We focus on the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in DWs. After considering the different DW structures in ferrom…
The gas-phase chemiionization reaction between samarium and oxygen atoms: A theoretical study
2004
The Sm + O chemiionization reaction has been investigated theoretically using a method that allows for correlation and relativistic effects. Potential energy curves have been calculated for several electronic states of SmO and SmO+. Comparison with available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemiionization reaction Sm + O is proposed. The importance of spin–orbit coupling in the excited states of SmO, in allowing this chemiionization reaction to take place, has been revealed by these calculations. This paper shows the metal-plus-oxidant chemiionization reaction.
Experimental data collection and modelling of dry deposition velocities for urban surfaces
2018
Dry deposition process is recognized as an important pathway among the removal processes of radioactive pollutants in atmosphere. There is not a unique and accepted theoretical description of involved dry deposition phenomena due to the complexity of the fluid-dynamic processes that influence the deposition flux, but also because there is a lack of experimental data covering all scenarios of interest. In this paper, that is the result of a National Research Program a research activity conducted by DEIM Department of the University of Palermo and ENEA and funded by the Italian Minister of Economic Development, a new schema for parameterization of particle dry deposition velocity on urban are…
The 3D modelling of musive surfaces for a monitoring protocol
2022
In questo lavoro l'utilizzo della metodologia digitale tridimensionale per la scansione di superfici musive è stato indagato nell'ambito dell'intervento di restauro di un mosaico pavimentale all'interno della Cappella Palatina di Palermo. Grazie alla possibilità di sezionare il modello di maglia con un software di rappresentazione digitale, è stato possibile confrontare la superficie della maglia con una superficie piana di riferimento allo scopo di valutare uno dei declini della posta dei pavimenti musivi, ovvero l'abrasione delle superfici In this paper the use of three-dimensional digital methodology for scanning musive surfaces was investigated within the restoration intervention on a f…
Deformation
2020
In the continuous model of a solid object, which is ideally considered composed of such material points that each one of them is surrounded by a dense neighbourhood fully occupied by other points, the deformation is a variation carried out by a transformation, which does not preserve isometry. Deformations differ from displacements caused by rigid motions. For a closed boundary curve in the three-dimensional space, Plateau wondered what surfaces would minimize the potential surface energy. Deformation was held to underlie the evolution of biological forms, described by the “Cartesian transformations”, or the interpolation function of landmarks covariation over a thin-plate spline, the perce…