Search results for "FeO"

Da Riccardo Quartararo a Cristoforo Faffeo. Un capolavoro del Museo Diocesano di Palermo restaurato e riscoperto

2016

Il volume, concepito secondo una metodologia multidisciplinare, propone all'attenzione degli studiosi nuovi dati per la conoscenza di una tavola dipinta dell'ultimo quarto del XV secolo proveniente al Museo Diocesano di Palermo dalla Cattedrale; finora attribuita a Riccardo Quartararo e identificata come Santa Cecilia solo per la presenza dell'angelo musico, l'opera viene qui correttamente riconosciuta, dopo il restauro, come Santa Barbara per l'imponente torre retrostante e attribuita al pittore napoletano Cristoforo Faffeo sulla base non solo di analogie stilistico-formali, ma di evidenze tecnico-esecutive e scientifiche nel confronto con altre opere riferite allo stesso e al Quartararo; …

Jauno viduslaiku koncepcija Nikolaja Berdjajeva filozofijā un tās aktualitāte mūsdienās

2015

Maģistra darbs veltīts krievu filozofa N.Berdjajeva 1924.gadā sarakstītajam darbam „Jaunie viduslaiki” un šajā darbā pausto ideju aktualitātei mūsdienās. Jauno viduslaiku koncepcija tiek apskatīta N.Berdjajeva vēstures filozofijas, varas metafizikas un citu XIX gs. beigu XX gs. sākuma Krievijas liberālās inteliģences pārstāvju ideju kontekstā. Tiek izpētīta koncepcijas rašanās un recepcija Krievijā. Jauno viduslaiku koncepcijas aktualitāte mūsdienās tiek analizēta galvenokārt saistībā ar Krieviju. Autors aplūko feodālās arhaikas elementu atgriešanos mūsdienu Krievijas sabiedrībā un N.Berdjajeva Jaunajiem viduslaikiem tuvo krievu sociologa un filozofa A.Zinovjeva virs-sabiedrības modeli.

Orfeo Boselli e la “nobiltà” della scultura

2002

Orfeo Boselli, scultore, teorico e restauratore, non ha lasciato significativa traccia di sé in nessuno dei campi in cui ebbe modo di cimentarsi e persino delle sue vicende biografiche e della sua produzione artistica si hanno notizie frammentarie. Sebbene il suo nome compaia in diversi testi di critica d’arte, la sua figura scivola silenziosa nel panorama dell’estetica seicentesca e, a tutt’oggi, non esistono opere monografiche che valorizzino il ruolo, certamente non secondario, che questo scultore, considerato “minore” dagli storici dell’arte, svolse nel dibattito teorico del suo tempo. Le Osservazioni della scoltura antica si inseriscono nella tradizione avviata dai teorici del Quattroc…

Orfeo in Sicilia: il mito nell'opera di Bufalino

2003

Orfeo o Tamiri? Cantori traci in Sicilia

2009

Orpheus and Thamyris are connected on the literary and iconographic levels, but reveal several divergencies as well. On an early Sicilian krater and an early Paestan hydria from Selinous, the depictions of Orpheus and Thamyris respectively allow us to reconsider the significance of the two singers as symbol of the Thracian music, in the Sicilian context and evaluate the use of these figurative subjects on Sicilian vases. The identity of the two musicians is not clearcut; the focal point is the music, in particular the Thracian, which acquires a divine and regenerating value in relation to the theme of the Underworld.

Dielectric properties and ac conductivities of Bi1−xSmxFeO3 ceramics

2019

Dielectric permittivity, dielectric losses and ac-conductivity of polycrystalline Bi1−xSmxFeO3 (x = 0; 0.05; 0.1; 0.15; 0.2) are measured in the frequency range 1 kHz–10 MHz and in the temperature range 25–600 °C. Anomalies have been observed at the 200 °C, 300 °C and at the Néel temperature. It has been demonstrated that doping with Sm has enhanced the dielectric properties and increased conduction in the frequency region 1 MHz) and at a certain temperature Tm, depending on the composition Bi1−xSmxFeO3, the conductivity reaches a maximum. The results are discussed with reference to the model of correlated barrier hopping.

Investigations of Low Temperature Phase Transitions in BiFeO3Ceramic by Infrared Spectroscopy

2011

In this paper, results of new infrared FIR-MIR measurements (wavenumber range of 4000–100 cm−1) in the range of the temperature 300 ÷ 8 K of the BiFeO3 ceramic are presented. Below 200 K only one symmetric band at ca. 800 cm−1 is visible. The full width at half maximum of this band decreases exponentially on cooling. The shape of the band at ca. 545 cm−1connected with A1 (TO) mode also changes between 60–40 K, this is in the vicinity of the phase transition at 50 K. Initially a broad band reveals its components as shoulder bands. Theirs FWHM decrease with cooling.

New solutions of the hamiltonian and diffeomorphism constraints of quantum gravity from a highest weight loop representation

1991

Abstract We introduce a highest weight type representation of the Rovelli-Smolin algebra of loop observables for quantum gravity. In terms of this representation, new solutions of the hamiltonian and diffeomorphism constraints are given. Assuming the locality of the quantum hamiltonian constraint we show that any functional depending on the generalized link class of the disjoint union of arbitrary simple loops is a solution. Finally we argue that this is the general solution in the irreducible representation space.

Solvable Models for radiating Black Holes and Area-preserving Diffeomorphisms

1995

Solvable theories of 2D dilaton gravity can be obtained from a Liouville theory by suitable field redefinitions. In this paper we propose a new framework to generate 2D dilaton gravity models which can also be exactly solved in the semiclassical approximation. Our approach is based on the recently introduced scheme to quantize massless scalar fields coupled to 2D gravity maintaining invariance under area-preserving diffeomorphisms and Weyl transformations. Starting from the CGHS model with the new effective action we reestablish the full diffeomorphism invariance by means of an adequate family of field redefinitions. The original theory is therefore mapped into a large family of solvable mo…

Moduli spaces of discrete gravity

2003

Spectral triples describe and generalize Riemannian spin geometries by converting the geometrical information into algebraic data, which consist of an algebra $A$, a Hilbert space $H$ carrying a representation of $A$ and the Dirac operator $D$ (a selfadjoint operator acting on $H$). The gravitational action is described by the trace of a suitable function of $D$. In this paper we examine the (path-integral-) quantization of such a system given by a finite dimensional commutative algebra. It is then (in concrete examples) possible to construct the moduli space of the theory, i.e. to divide the space of all Dirac operators by the action of the diffeomorphism group, and to construct an invaria…