Search results for "Insula"
showing 10 items of 735 documents
Exotic Spin-Orbital Physics in Hybrid Oxides
2016
We compare the effective spin-orbital super\-exchange triggered by magnetic $3d$ impurities with $d^3$ and $d^2$ configurations and either no orbital degree of freedom (orbital dilution) or hole replacing a doublon (charge dilution) in a $4d^4$ Mott insulator with $S=1$ spins. Impurities causing orbital dilution act either as spin defects decoupled from the surrounding ions, or generate orbital polarons along $d^3$-$d^4$ hybrid bonds. The exchange on these bonds determines which orbital is occupied by a doublon on the host site. In case of charge dilution by $3d^2$ impurities additional $\propto T_i^+T_j^+$ terms arise which enhance orbital fluctuations. We show that such terms may radicall…
Quando i recinti tracimeranno. Lo sprawl e le insulae dello ZEN 2
2008
Dal 1989 mi interesso al quartiere ZEN di Palermo, al quale ho dedicato la tesi di dottorato, alcuni articoli, una monografia, molte lezioni, diversi progetti e, ovviamente, moltissimi sopralluoghi. Sono trascorsi, quindi, circa venti anni dalla fase iniziale di studio e ho avuto modo, in questo periodo, di seguire quelle trasformazioni che, insieme al quartiere, hanno riguardato l’area più a nord della Piana dei Colli. Punti di vista privilegiati per seguire e comprendere tali mutamenti sono il Monte Pellegrino e la strada panoramica che, almeno per una parte, si srotola, come un nastro, lungo il fianco che limita ad est il parco de La Favorita. Da molti degli sguardi offerti dal monte, c…
Stikla pakešu konstruktīvo parametru automatizēta noteikšana
2021
Maģistra darba mērķis ir izstrādāt programmatūru, kas pēc ievades datiem spēj būvinženierim parādīt vairākus iespējamos stikla paketes uzbūves variantus, kas atbilst konstruktīvajām prasībām normatīvos. Darbā implementēti vadlīnijās aprakstīti vienkāršojumi, lai izveidotu ātri aprēķināmus galīgo elementu modeļus. Uz ~2 miljonu galīgo elementu modeļu aprēķinu bāzes ir trenēti neironu tīklu “surogāta modeļi”. Iegūta >98% precizitāte, izmantojot Google piedāvātu automatizētu mašīnmācīšanās risinājumu. Izveidotie neironu tīklu modeļi sasniedz ~160-kārtīgu ātruma palielinājumu salīdzinot ar galīgo elementu aprēķiniem, vienu pilnu stiklu paketes izvērtējumu paātrinot līdz ~300 milisekundēm. Šāds …
Quantitative reconstruction of hydroclimate variability over the last 200 kyr in the West Mediterranean
2022
The data show the quantitative annual, winter and summer precipitation reconstructions (mm/yr) from southern Iberian Peninsula for the last ~200,000 years (Camuera et al., 2022), based on the previously published fossil pollen data from the Padul-15-05 lake sediment record (Ramos-Román et al., 2018a, b; Camuera et al., 2019, 2021). The Padul-15-05 record, located in southern Spain (37º00'39''N, 3º36'14''W, 726 masl), was retrieved during summer 2015 from the current edge of the lake using a Rolatec RL-48-L hydraulic percussion coring machine. The quantitative precipitation reconstructions were performed using the performance statistics of the Weighted Averaging-Partial Least Squares (WA-PLS…
Topological polarization, dual invariants, and surface flat band in crystalline insulators
2020
We describe a three-dimensional crystalline topological insulator (TI) phase of matter that exhibits spontaneous polarization. This polarization results from the presence of (approximately) flat bands on the surface of such TIs. These flat bands are a consequence of the bulk-boundary correspondence of polarized topological media, and contrary to related nodal line semimetal phases also containing surface flat bands, they span the entire surface Brillouin zone. We also present an example Hamiltonian exhibiting a Lifshitz transition from the nodal line phase to the TI phase with polarization. Utilizing elasticity tetrads, we show a complete classification of 3D crystalline TI phases and invar…
Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
2019
We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for microscopic tight-binding and low-energy continuum models. We predict qualitative differences between local and non-local interaction schemes which could be distinguished experimentally. In the flat band limit where the pair potential exceeds the band width we show that the superfluid weight and BKT temperature are determined by multiband processes and quantum geometry of the band.
Mystemys giganteus n. gen. et sp.: an enigmatic and rare cricetid from the Terre Rosse M013 fissure filling (Gargano, Southeastern Italy).
2016
Mystemys giganteus is a new strongly endemic cricetid that occurs only in the recently discovered M013 Terre Rosse fissure filling of the Gargano area. This species was presented alongside the other taxa of the M013 fissure in a previous paper and it is here described in detail. Although the material includes only five molars, Mystemys is exceptional for its very large size (length of M1: 6.23 mm) and peculiar morphology. The molars are heavy built with bulged and robust cusps, tubercular crests, narrow valleys, very thick and crenulated enamel. The morphological features of Mystemys are very carefully described, with special focus on the evolutionary modifications induced by isolation. The…
Hacia el actor profesional en el teatro peninsular del Renacimiento
2015
Los albores del Renacimiento peninsular ven nacer unas prácticas escénicas dependientes del Poder, creadas y desarrolladas en la Corte por los llamados padres del teatro castellano y portugués: Juan del Encina, Lucas Fernández y Gil Vicente. No siempre se ha prestado atención a su producción desde el punto de vista de la puesta en escena y aún menos a los actores que la ejecutaron. Esta Tesis Doctoral pretende abrir una senda hacia el estudio de la actuación de estos primeros representantes luso-castellanos, durante la etapa anterior a la profesionalización del oficio. La investigación se inicia mediante la elaboración de un marco teórico que recupera los materiales que marcaron el desarrol…
Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future.
2020
As the need for green and effective utilization of energy continues to grow, the advancements in the energy and power electronics industry are constantly driven by this need, as both industries are intertwined for obvious reasons. The developments in the power electronics industry has over the years hinged on the progress of the semiconductor device industry. The semiconductor device industry could be said to be on the edge of a turn into a new era, a paradigm shift from the conventional silicon devices to the wide band gap semiconductor technologies. While a lot of work is being done in research and manufacturing sectors, it is important to look back at the past, evaluate the current progr…
The resonant state at filling factor {\nu} = 1/2 in chiral fermionic ladders
2017
Helical liquids have been experimentally detected in both nanowires and ultracold atomic chains as the result of strong spin-orbit interactions. In both cases the inner degrees of freedom can be considered as an additional space dimension, providing an interpretation of these systems as synthetic ladders, with artificial magnetic fluxes determined by the spin-orbit terms. In this work, we characterize the helical state which appears at filling $\nu=1/2$: this state is generated by a gap arising in the spin sector of the corresponding Luttinger liquid and it can be interpreted as the one-dimensional (1D) limit of a fractional quantum Hall state of bosonic pairs of fermions. We study its main…