970 resultados para mixing of states


Relevância:

90.00% 90.00%

Publicador:

Resumo:

“A Narratological Analysis of D. M. Thomas’s The White Hotel (1981)” originated within a seminar on British Postmodernist Literature during the first Master’s Degree in “British and North-American Culture and Literature” (2001-04) at the Universidade da Madeira set up by the Department of English and German Studies. This dissertation seeks to present a narratological analysis of Thomas’s novel. The White Hotel stands as a paradigmatic example of the kind of literature that has dominated the British literary scene in the past three decades, commonly referred to as postmodernist fiction, owing to its formal craftsmanship (multiplicity of narrative voices and perspectives, mixing of differing genres and text types, inclusion of embedded narratives) alongside the handling of what are deemed as postmodernist topoi (the distinction between truth and lies, history and fantasy, fact and fiction, the questioning of the nature of aesthetic representation, the role the author and the reader hold in the narrative process, the instability of the linguistic sign, the notion of originality and the moral responsibility the author has towards his/her work), The narratological approach carried out in this research reveals that Thomas’s text constitutes an aesthetic endeavour to challenge the teleological drive that is inherent in any narrative, i. e., the inevitable progression towards a reassuring end. Hence, the subversion of narrative telling, which is a recurrent feature in Thomas’s remaining literary output, mirrors the contemporary distrust in totalising, hierarchised and allencompassing narratives. In its handling of historical events, namely of the Holocaust, The White Hotel invites us to reassess the most profound beliefs we were taught to take for granted: progress, reality and truth. In their place the novel proposes a more flexible conception of both the world and art, especially of literary fiction. In other terms, the world appears as a brutal chaotic place the subject is forced to adjust to. Accordingly, the literary work is deemed hybrid, fragmented and open. So as to put forth the above-mentioned issues, this research work is structured in three main chapters. The initial chapter – “What is Postmodernism?” – advances a scrutiny not only of the seminal but also of more recent studies on postmodernist literary criticism. Following this, in Chapter II – “Postmodernist British Fiction” – a brief overview of postmodernist British fiction is carried out, focusing on the fictional works that, in my opinion, are fundamental for the periodising of British postmodernism. In addition, I felt the need to include a section – “D. M. Thomas as a Postmodernist Novelist” – in which the author’s remaining literary output is briefly examined. Finally, Chapter III – “A Narratological Analysis of The White Hotel” – proposes a narratological analysis of the novel according to the particular Genettian analytical model. To conclude, my dissertation constitutes an approach to D. M. Thomas’s The White Hotel as a text whose very existence is substantiated in the foregrounding of the contingency of all discourses, meeting the postmodernist precepts of openness and subversion of any narrative that claims to be true, globalising and all-inclusive.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Persistent photoconductivity (PPC) in vanadyl phthalocyanine (VOPc) organic light-emitting diodes was investigated using photoconductive time response, photocurrent-voltage characteristics and charge extraction in linearly increasing voltage (CELIV) measurements. The experiments were performed in phase 1 (amorphous) and in phase 2 (crystalline) samples obtained by the physical vapour deposition (PVD) technique over ITO/glass electrodes with an Al covering electrode. The results indicated a photoconductivity with a long decay time in phase 1 VOPc described by a stretched exponential relaxation. The device showed a rectifying behaviour and the mobility of holes was measured by CELIV, following a dispersive model. In crystalline samples the PPC effect was not observed and the dominant mechanism of transport of holes was hopping in a Gaussian density of states.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The FePt alloy undergoes the cubic to tetragonal lattice transformation in the ferromagnetic state. We calculated the electronic structure for both cubic and tetragonal structures using the FPLAPW method with APW + lo. Comparing the density of states of the cubic and tetragonal structures, it is expected that the lattice transformation is caused by the band Jahn-Teller effect. (C) 2009 Elsevier B.V. All rights reserved.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Density functional calculation at B3LYP level was employed to study the surface oxygen vacancies and the doping process of Co, Cu and Zn on SnO2 (110) surface models. Large clusters, based on (SnO2)(15) models, were selected to simulate the oxidized (Sn15O30), half-reduced (Sn15O29) and the reduced (Sn15O28) surfaces. The doping process was considered on the reduced surfaces: Sn13Co2O28, Sn13Cu2O28 and Sn13Zn2O28. The results are analyzed and discussed based on a calculation of the energy levels along the bulk band gap region, determined by a projection of the monoelectron level structure on to the atomic basis set and by the density of states. This procedure enables one to distinguish the states coming from the bulk, the oxygen vacancies and the doping process, on passing from an oxidized to a reduced surface, missing bridge oxygen atoms generate electronic levels along the band gap region, associated with 5s/5p of four-/five-fold Sn and 2p of in-plane O centers located on the exposed surface, which is in agreement with previous theoretical and experimental investigations. The formation energy of one and two oxygen vacancies is 3.0 and 3.9 eV, respectively. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The structural and electronic properties of bulk and both oxidized and reduced SnO2(110) surfaces as well as the adsorption process of O-2 on the reduced surface have been investigated by periodic DFT calculations at B3LYP level. The lattice parameters, charge distribution, density of states and band structure are reported for the bulk and surfaces. Surface relaxation effects have been explicitly taken into account by optimizing slab models of nine and seven atomic layers representing the oxidized and reduced surfaces, respectively. The conductivity behavior of the reduced SnO2(110) surface is explained by a distribution of the electrons in the electronic states in the band gap induced by oxygen vacancies. Three types of adsorption approaches of O-2 on the four-fold tin at the reduced SuO(2)(110) surface have been considered. The most exothermic channel corresponds to the adsorption of O-2 parallel to the surface and to the four-fold tin row, and it is believed to be associated with the formation of a peroxo O-2(2-) species. The chemisorption of O-2 on reduced SnO2(110) surface causes a significant depopulation of states along the band gap and it is shown to trap the electrons in the chemisorbed complex producing an electron-depleted space-charge layer in the inner surface region of the material in agreement with some experimental evidences. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

90.00% 90.00%

Publicador:

Resumo:

A strong greenish-light photoluminescence (PL) emission was measured at room temperature for disordered and ordered powders of CaMoO4 prepared by the polymeric precursor method. The structural evolution from disordered to ordered powders was accompanied by XRD. Raman spectroscopy, and TEM imagery. High-level quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states. Complex cluster vacancies [MoO3 center dot V-O(z)] and [CaO7 center dot V-O(z)] (where V-O(z) = V-O(X), V-O(center dot), V-O(center dot center dot)) were suggested to be responsible to the appearance of new states shallow and deeply inserted in the band gap. These defects give rise to the PL in disordered powders. The natural PL emission of ordered CaMoO4 was attributed to an intrinsic slight distortion of the [MoO4] tetrahedral in the short range.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The problem of a fermion subject to a general mixing of vector and scalar potentials in a two-dimensional world is mapped into a Sturm-Liouville problem. Isolated bounded solutions are also searched. For the specific case of an inversely linear potential, which gives rise to an effective Kratzer potential in the Sturm-Liouville problem, exact bounded solutions are found in closed form. The case of a pure scalar potential with their isolated zero-energy solutions, already analyzed in a previous work, is obtained as a particular case. The behavior of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed. The nonrelativistic limit of our results adds a new support to the conclusion that even-parity solutions to the nonrelativistic one-dimensional hydrogen atom do not exist. (c) 2004 Elsevier B.V. All rights reserved.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The problem of a spinless particle subject to a general mixing of vector and scalar screened Coulomb potentials in a two-dimensional world is analyzed and its bounded solutions are found. Some unusual results, including the existence of a bona fide solitary zero-eigenmode solution, are revealed for the Klein-Gordon equation. The cases of pure vector and scalar potentials, already analyzed in previous works, are obtained as particular cases.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The problem of a fermion subject to a general mixing of vector and scalar screened Coulomb potentials in a two-dimensional world is analyzed and quantization conditions are found.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The problem of a fermion subject to a convenient mixing of vector and scalar potentials in a two-dimensional space-time is mapped into a Sturm-Liouville problem. For a specific case which gives rise to an exactly solvable effective modified Poschl-Teller potential in the Sturm-Liouville problem, bound-state solutions are found. The behaviour of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed. The Dirac delta potential as a limit of the modified Poschl-Teller potential is also discussed. The problem is also shown to be mapped into that of massless fermions subject to classical topological scalar and pseudoscalar potentials. Copyright (C) EPLA, 2007.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The problem of fermions in the presence of a pseudoscalar plus a mixing of vector and scalar potentials which have equal or opposite signs is investigated. We explore all the possible signs of the potentials and discuss their bound-state solutions for fermions and antifermions. The cases of mixed vector and scalar Poschl-Teller-like and pseudoscalar kink-like potentials, already analyzed in previous works, are obtained as particular cases.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)