II Encontro da Pós-Graduação

em Física e Astronomia da UFSC

Dias 5 a 9 de Maio de 2014.

Braso UFSC

Resumos Submetidos

Lista de resumos de todas as apresentações (poster: icone poster e oral: icone oral) submetidos até o momento.

PosterA QM/MM method for long range charge transfer
Diego A. Hoff; Robson da Silva; Bruno C. Hamel; Luis G. C. Rego
Neste trabalho apresentamos um método capaz de descrever as dinâmicas
eletrônica (quântica) e nuclear (clássica) de sistemas moleculares e
supramoleculares considerando, entre outros, os efeitos de interação
carga - dipolo induzido e o acoplamento entre os graus de liberdade
eletrônicos e nucleares. Desta forma, é possível descrever a
dinâmica quântica do sistema eletrônico ao longo da evolução da
dinâmica molecular.
PosterCharacterization of LBL films containing Pheophytin-b
Gisele E. Nunes Pauli; Felipe B. Araruna; José Roberto S. A. Leite; Carla Eiras; Otemberg Souza Chaves; Severino Gonçalves Brito Filho; Maria de Fátima Vanderlei Souza; Ivan H. Bechtold;
The self-assembled layer-by-layer (LbL) technique is a method based on alternate adsorption of oppositely charged polyelectrolytes, through electrostatic interactions, leading to well organized films with a precise control of the film thickness [1]. Due to its versatility and simplicity, it has been explored for a wide variety of systems including those containing azodyes [2, 3], biological systems [4], etc. Pheophytin-b is a compound derived from chlorophyll, with nanobiomedical properties that have been studied for use in Photodynamic Therapy [5].
In this work we produce LbL films with pheophytin-b (isolated from the plant Turnera subulata, and the biological material collected Campus UFPB/ Paraiba), together with a cationic polymer poly(allylamine hydrochloride) (PAH). The multilayer formation was investigated via UV–Vis spectroscopy by monitoring the 410 nm absorption band associated to pheo-b, where distinct molecular interactions between the materials were verified. The morphology of the films was analyzed by atomic force microscopy (AFM). The electrochemical properties through redox behavior of pheo-b were studied with cyclic voltammetry. The produced films were applied as sensors for hydrogen peroxide detection. In terms of sensing, PAH/pheo-b films exhibited promising results.

Keywords: Pheophytin-b, Layer-by-Layer (LBL) technique, Biosensors.

[1] G. Decher, Science 277, 1232, (1997).
[2] V. Zucolotto, P. J. Strack, F. R. Santos, D. T. Balogh, C. J. L. Constantino, C. R. Mendonça and O. N. Oliveira, Thin Solid Films, 453, 110, ( 2004).
[3] Nunes, G.E.; Sehnem, A.L.; and Bechtold, I.H. Liquid Crystals,Vol. 39, No. 2, p.205, 2012.
[4] Crespilho, F. N.; Zucolotto, V.; Siqueira Jr., J. R.; Constantino, C. J. L.; Nart, F. C.; Oliveira Jr., O. N. Environ. Sci. Techol., 39, 5385, 2005.
[5] Ribeiro, J. N.; Jorge, R. A.; Silva, A. R.; Flores, A. V.; Ronchi1, L. M.; Tedesco, A. C. Ecl. Quím.,Vol. 32, No. 1: p.7, 2007.
OralResolving galaxies in time and space: Applying STARLIGHT to CALIFA data cubes
A. L. de Amorim; R. Cid Fernandes; Perez, E.;R. Garcia Benito; R. M. Gonzalez Delgado; S. F. Sanchez; B. Husemann; J. Falcon Barroso; P. Sanchez-Blazquez; C. J. Walcher; D. Mast
Fossil record methods based on spectral synthesis techniques have
matured over the past decade, and their application to integrated
galaxy spectra fostered substantial advances on the understanding of
galaxies and their evolution. Yet, because of the lack of spatial
resolution, these studies are limited to a global view, providing no
information about the internal physics of galaxies.Motivated by the
CALIFA survey, which is gathering Integral Field Spectroscopy over the
full optical extent of 600 galaxies, we have developed an end-to-end
pipeline which: (i) partitions the observed data cube into Voronoi
zones in order to, when necessary and taking due account of correlated
errors, increase the S/N, (ii) extracts spectra, including propagated
errors and bad-pixel flags, (iii) feeds the spectra into the STARLIGHT
spectral synthesis code, (iv) packs the results for all galaxy zones
into a single file, (v) performs a series of post-processing
operations, including zone-to-pixel image reconstruction and unpacking
the spectral and stellar population properties into multi-dimensional
time, metallicity, and spatial coordinates.This work provides a
description of this whole pipeline and its data products. These
include 3D cubes of the stellar formation history, 2D maps of galaxy
properties such as the v-field, stellar extinction, mean ages and
metallicities, mass surface densities, star formation rates on
different time scales and normalized in different ways, 1D averages in
the temporal and spatial dimensions, projections of the stellar light
and mass growth (x,y,t) cubes onto radius-age diagrams, etc. The
results illustrate the richness of the combination of IFS data with
spectral synthesis, providing a glimpse of what is to come from CALIFA
and future IFS surveys.
OralObjetos Compactos Estelares e Modelos Relativísticos
James R. Torres; Debora P. Menezes
O objetivo deste trabalho é descrever a matéria no interior dos objetos compactos remanescentes de uma explosão de supernova usando modelos relativísticos conhecidos na literatura. O desafio é encontrar a equação de estado que resulte no perfil estelar que esteja de acordo com as massas dos pulsares recentemente descobertos. Abordaremos além da matéria hadrônica a matéria estelar puramente quarkiônica levando em conta a conjectura da matéria estranha.
OralReduced dimensionality induced magnetic stripe phase in Fe nanoislands
Jeison A. Fischer; Soo-hyon Phark; Marco Corbetta; Dirk Sander; André A. Pasa; Jürgen Kirschner
Low-dimensionality in itinerant magnetic materials often leads to magnetic ground states of non-collinear magnetic order [1], such as spin helices and skyrmions. Recent theoretical works predicted that competing exchange interactions induce a spin helix in bcc Fe(110) monolayers [2]. Here we report an observation of a magnetic stripe phase with a period of 1.28 nm in bilayer Fe nanoislands on Cu(111) [3]. In-field spin-polarized scanning tunneling microscopy and spectroscopy reveals that the stripe phase originates from a helical spin ordering. Together with theoretical insights [2], our finding provides compelling experimental evidence that a non-collinear magnetic ordering can be stabilized in a system where a long-range antiferromagnetic exchange interaction is enhanced due to a reduced dimensionality.

[1] S. Mühlbauer, B. Binz, F. Jonietz, C. Pfleiderer, A. Rosch, A. Neubauer, R. Georgii, P. Böni, Science 323, 915 (2009).
[2] K. Nakamura, N. Mizuno, T. Akiyama, T. Ito, A. Freeman, J. Appl. Phys. 99, 08N501 (2006).
[3] A. Biedermann, W. Rupp, M. Schmid, P. Varga, Phys. Rev. B 73, 165418 (2006).
Desenvolvido por Maurício Girardi Schappo.
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