¿Un espectroscopio casero? : jugando con los espectros en las ciencias para el mundo contemporáneo.

Las técnicas de análisis de espectros, utilizadas en astrofísica, ofrecen una oportunidad excelente para motivar al alumnado en la materia de Ciencias para el mundo contemporáneo impartida en primero de bachillerato. Además, resulta sencillo y barato construir un pequeño espectroscopio analítico para pasar de la teoría a la práctica. Se pasa revista a varias páginas web en las que se explican diferentes maneras de construir espectroscopios caseros, a partir de materiales diversos y fáciles de conseguir.

Dispersión de la luz. Espectros.

Se hace un repaso por el desarrollo que han tenido experimentos y descubrimientos relacionados con la luz, tales como: la dispersión de la luz, el acromatismo, la espectroscopia, el descubrimiento del helio, la extensión del espectro, prismas y redes, la energía de las radiaciones y las aplicaciones de la espectroscopia.

Espectros e silhuetas em uma cidade: imagens da mulher no cinema brasileiro de 1896 a 1928

O presente trabalho analisa a mulher na produção cinematográfica brasileira de 1896/1928, período que cobre um momento importante do debate sobre as alterações dos papéis sociais em meio às alterações trazidas com a modernidade.O Cinema Brasileiro apresenta-se como um

Crescimento in vitro e aclimatização de Cattleya loddigesii Lindley (Orchidaceae) com carvão ativado sob dois espectros luminosos

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

Síntese e caracterização de compostos de coordenação homolépticos e heterolépticos com o ligante ácido kójico

The present work has as main objective to contribute to the coordination chemistry of the ligand kojic acid, with the synthesis and characterization of the homoleptic compounds [Al(kj)3], [Fe(kj)3], [Fe(kj)2], [Cu(kj)2] e [Ru(kj)3], and the new heteroleptic complexes, trans- K2[Fe(kj)2(CN)2] and trans-Na2[Ru(kj)2(CN)2]. The obtained compounds were characterized by vibrational spectroscopy in the infrared region (IV) and Electronic spectroscopy in the ultraviolet and visible region (Uv-Vis). The infrared results indicated the coordination of the bidentate ligand kojic acid, due to reductions in the values of the stretching frequencies of the carbonyl and double bonds, compared to the free ligand for all complexes obtained. The presence of new vibrational modes indicated the change of symmetry of the molecules in the new compounds synthesized. Additionally, the presence of vibrational modes assigned to metal-oxygen also contributed to confirm the ligand coordinating to the metal ions. Through this technique, was also possible to perform correlations of the numbers of vibrational modes, in the region 1400-900 cm-1 and the compounds geometry. The heteroleptic compounds exhibited υC≡N in 2065 and 2053 cm-1, respectively, for the trans-K2[Fe(kj)2(CN)2] and trans-Na2[Ru(kj)2(CN)2], indicating coordination of the cyano ligand to metal ions FeII e RuII. Comparing the obtained values with literature data was possible to identify the complex isomerism as trans. In relation to the results of electronic spectroscopy, studies of pH variation of kojic acid provided information on the distribution of electron density in the molecule, showing characteristic spectral profile of kojic ion and its protonated form (Hkj, kojic acid), with two bands at 215 and 269 nm, or deprotonated (kj-), with bands at 226 and 315 nm. The electronic spectra obtained for all complexes in aqueous medium, in the ultraviolet region, exhibited variations of the energies assigned to kojic acid intraligand transitions while in the visible region, only transitions assigned to charge transfer of iron and ruthenium complex have been identified

Espectros fractais em sistemas nanoestruturados e cristais fotônicos

The study of the elementary excitations such as photons, phonons, plasmons, polaritons, polarons, excitons and magnons, in crystalline solids and nanostructures systems are nowdays important active field for research works in solid state physics as well as in statistical physics. With this aim in mind, this work has two distinct parts. In the first one, we investigate the propagation of excitons polaritons in nanostructured periodic and quasiperiodic multilayers, from the description of the behavior for bulk and surface modes in their individual constituents. Through analytical, as well as computational numerical calculation, we obtain the spectra for both surface and bulk exciton-polaritons modes in the superstructures. Besides, we investigate also how the quasiperiodicity modifies the band structure related to the periodic case, stressing their amazing self-similar behavior leaving to their fractal/multifractal aspects. Afterwards, we present our results related to the so-called photonic crystals, the eletromagnetic analogue of the electronic crystalline structure. We consider periodic and quasiperiodic structures, in which one of their component presents a negative refractive index. This unusual optic characteristic is obtained when the electric permissivity and the magnetic permeability µ are both negatives for the same range of angular frequency ω of the incident wave. The given curves show how the transmission of the photon waves is modified, with a striking self-similar profile. Moreover, we analyze the modification of the usual Planck´s thermal spectrum when we use a quasiperiodic fotonic superlattice as a filter.

Espectros Clínicos da Trombose Venosa Cerebral

Introduction. Cerebral Venous Thrombosis has a highly variable clinical presentation. Four major syndromes had been described in patients with cerebral venous thrombosis: isolated intracranial hypertension, focal neurological deficits, focal or generalized seizures and disturbances of consciousness and cognitive dysfunction. Method. We describe five consecutive patients admitted to our service with a diagnosis of cerebral venous thrombosis, highlighting the different possibilities of clinical presentation and prognosis. Discussion. The diagnosis of cerebral venous thrombosis should be considered in patients with acute, subacute or chronic headache, with or without signs of intracranial hypertension or focal deficits, even in the absence of cerebrovascular risk factors. Treatment should be started as soon as the diagnosis is confirmed and consists of reversal of the underlying cause when known, control of seizures and intracranial hypertension, and antithrombotic therapy.

Análise quantitativa de espectros de absorção no infravermelho de compósitos odontológicos fotoativados

Pós-graduação em Ciência dos Materiais - FEIS

Fabricação e caracterização de filmes finos de perileno: arquitetura molecular e aplicações sensoriais

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

Espectros de reflectância difusa como técnica auxiliar na caracterização da emissão de CO2 e atributos do solo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Propriedades fotoluminescentes de PbMoO4 obtidos a partir dos métodos de coprecipitação e processamento hidrotérmico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de queilite actínica por espectroscopia micro FT-IR

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Espectros de raios-x em MEV indicam associação entre Al e Si em plantas acumuladoras de Al do Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)