Molecular engineering strategies to control photo-induced birefringence and surface-relief gratings on layer-by-layer films from an azopolymer

The interactions governing adsorption of layer-by-layer (LBL) films from an azopolymer, PS-119(R), and poly(allylamine hydrochloride) (PAH) have been controlled by modifying the pH of the solutions used to form the films. The thickness per bilayer was varied by one order of magnitude, from 10 to 240 A, as the pH changed from 4 to 10. Thick layers were formed at higher pHs because in this case the PAH is only partially charged adopting a loopy conformation. This change in molecular conformation caused the kinetics of isomerization and mass transport to be much slower than at lower pHs. The writing time defined as the time to achieve 50% of maximum birefringence dropped from 110 to 18 min for films prepared from solutions with pH 10 and pH 4, respectively. This decrease is probably due to the higher free volume for isomerization in the films prepared at lower pHs, in which PAH molecules are less coiled than at higher pHs. For the same reason, the rate of inscription of surface-relief gratings with an interference pattern of p-polarized light was also much slower at higher pHs. (C) 2003 Elsevier B.V. All rights reserved.

Otimização de processos semi-automáticos de detecção de alterações aplicadas ao cadastro imobiliário

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O senhor dos anéis: a tradutora na obra traduzida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A saúde mental no Programa de Saúde da Família: estudo sobre práticas e significações de uma equipe

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Entorno da sustentabilidade: a reserva da biosfera do Cinturão Verde da cidade de São Paulo (1971 – 2008)

Pós-graduação em História - FCLAS

Escrita e diálogo: heterogeneidade no gênero prova discursiva de língua portuguesa do vestibular da UFG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inverse relaxation effect of azo-dye molecules: The role of the film anisotropy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tailoring the refractive index of Ge-S based glass for 3D embedded waveguides operating in the mid-IR region

The photosensitivity of GeSx binary glasses in response to irradiation to femtosecond pulses at 800 nm is investigated. Samples with three different molecular compositions were irradiated under different exposure conditions. The material response to laser exposure was characterized by both refractometry and micro-Raman spectroscopy. It is shown that the relative content of sulfur in the glass matrix influences the photo-induced refractive index modification. At low sulfur content, both positive and negative index changes can be obtained while at high sulfur content, only a positive index change can be reached. These changes were correlated with variations in the Raman response of exposed glass which were interpreted in terms of structural modifications of the glass network. Under optimized exposure conditions, waveguides with positive index changes of up to 7.8x10−3 and a controllable diameter from 14 to 25 μm can be obtained. Direct inscription of low insertion losses (IL = 3.1 – 3.9 dB) waveguides is demonstrated in a sample characterized by a S/Ge ratio of 4. The current results open a pathway towards the use of Ge-S binary glasses for the fabrication of integrated mid-infrared photonic components.

Processo e produção visual do graffitti na cidade de Bauru/SP - Brasil: um estudo etnográfico

The graffiti is a calligraphic inscription or a drawn painted or engraved over a supported not normally used for this purpose. This artistic manifestation has been gaining more notoriety as an element of expression, reflection and actuation in the urban environment, since it is present in the streets and public ways reaching many observers with different repertoires and looks. This recent movement in Brazil has its first records in the early 80’s, but it is noteworthy that this event continues in an emergence process, consolidating increasingly as an artistic movement, in broad development, elaborating new technics, readjust and re-signifying its elements, re-improving and generating different values for the spaces. With the purpose to map the graffiti artists in Bauru/SP – Brazil, it was done an ethnography that allows to point some specific local characteristics; the relation between the artist and the city, and; the relation between the townsman and the graffiti.

O estilo em psicanálise: o discurso do analista como arte do bem dizer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)