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Now showing items 31-40 of 50
Interação plasmon-fônon LO em superredes semicondutoras
(Universidade Federal de São Carlos, 2008-10-07)
This work presents a Raman investigation of the optical vibrations in highly doped In-GaAs/InP and GaAs/AlGaAs superlattices (SL s). The InGaAs/InP SL s grown with different
periods were analyzed using polarized Raman ...
Ordenamento ferromagnético em poli(3-hexiltiofeno) à temperatura ambiente
(Universidade Federal de São Carlos, 2009-07-14)
In this work we present, for the first time, a systematic study of magnetic properties of an alkyl derivative of thiophene: the poly(3-hexylthiophene) prepared in acetonitrile. This polymer was investigated in different ...
Ansatz de Bethe para cadeias quânticas de spin-1 com condições de contorno
(Universidade Federal de São Carlos, 2002-03-21)
The procedure for obtaining integrable open spin chain Hamiltonians via reflection
matrices explicitly carried out for some three-state vertex models. We have considered
the 19-vertex models of Zamolodchikov-Fateev and ...
Processos quânticos em cavidades com a geometria variável.
(Universidade Federal de São Carlos, 2004-03-11)
In this thesis, we study the quantum de ection of ultracold particles by mirrors, the shrinking of free wave packets, the tunnelling of narrow Gaussian packets through delta potentials and the entanglement between the modes ...
Regras de ocupação e influência de dopantes trivalentes em matrizes cerâmicas transparentes de PLZT 9/65/35
(Universidade Federal de São Carlos, 2009-10-01)
In this work, were investigated the occupancy of rare-earth ions in lattice site of the ferroelectric system (Pb,La)(Zr,Ti)O3, or PLZT. The influence on the structural, microestructural, dielectric, ferroelectric, optical ...
O efeito Casimir dinâmico e decoerência
(Universidade Federal de São Carlos, 2008-07-03)
In this thesis we first demonstrate that the inevitable action of the environment can be substantially weakened when considering appropriate nonstationary quantum systems. Beyond protecting quantum states against decoherence, ...
Estudo de efeitos quânticos em redes de junções Josephson SNS e SIS com composição Nb-CuxAlyOz-Nb através da indução de vórtices por conseqüência do tamanho de rede
(Universidade Federal de São Carlos, 2009-10-16)
In this thesis we studied the quantum effects in networks of Josephson junctions under the induction of vortices and as a consequence of the size of the sample itself. For this, it also was carried out all the instrumentation ...
Modelos magnéticos com frustração e diluição
(Universidade Federal de São Carlos, 2006-12-08)
In this work, we investigate the effect of dilution and frustration in the thermodynamic properties and the phase diagrams using the quasi-two-dimensional Heisenberg and Ising models. We use the Zubarev Green´s function ...
Estudos de avalanches de vórtices em filmes supercondutores de Nb e MgB2
(Universidade Federal de São Carlos, 2008-10-28)
If a type-II superconductor is cooled down in a zero applied field and subsequently an external field, larger than the first critical field, is applied, vortices enter through the sample borders until they are captured by ...
Origem dos momentos magnéticos localizados em ligas de cromo com metais de transição por oscilações de Friedel
(Universidade Federal de São Carlos, 2006-08-02)
The fundamental magnetic properties of chromium and its alloys Cr(1¡x)Nb(x) and Cr(1¡x)V(x), were investigated with the aim to achieve a better comprehension about the nature of the spin density waves. Was dened the edge ...