Brillouin Scattering
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Hot electron transport properties in characteristics of wurtzite GaN MESFETs using a five-valley model
Ensemble Monte Carlo simulations have been carried out to investigate the effects of upper valleys on the characteristics of wurtzite GaN MESFETs. Electronic states within the conduction band valleys at the Γ1, U, M, Γ3 and K are represented by non-parabolic ellipsoidal valleys centred on important symmetry points of the Brillouin zone. The following scatt
Brazilian Journal of Physics. Publicado em: 2010-09
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2. Controle e interação de fonons e fotons em fibras opticas de cristal fotonico / Control and interaction of phonons and photons in photonic crystal fibers
Techniques that may allow control and tight confinement of photons and phonons in photonic crystal fibers (PCFs) are investigated in this thesis. By means of robust numerical methods to solve Maxwell equations, a new kind of PCF with a tubular core is proposed. Simulations and experimental results show that such structure is able to confine light tighly insi
Publicado em: 2008
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3. Brillouin scattering in photonic fibers / Espalhamento Brillouin em fibras fotonicas
ormado.
Publicado em: 2006
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4. Estudo de amplificadores parametricos para sistemas de comunicações opticas de altas taxas de transmissão / Study of parametric amplifiers for high bit rate optical communication systems
This thesis presents a theoretical and experimental study on fiber optics parametric amplifiers. For the double-pumped case, we show the performance of the amplifier in terms of spectral bandwidth and gain uniformity, both fundamental properties for WDM applications. By using short dispersion shifted fibers and highly non-linear fibers, we made parametric am
Publicado em: 2006
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5. Sensores distribuidos utilizando efeitos não-lineares em fibras opticas para aplicação em estruturas inteligentes
Sensores distribuídos a fibra óptica representam uma tecnologia chave para o desenvolvimento de estruturas inteligentes, uma vez que podem ser totalmente integrados aos materiais da estrutura. Efeitos ópticos não lineares podem ser utilizados para implementar esta nova classe de sensores, sem a necessidade da construção de componentes sensores individu
Publicado em: 2004
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6. Propriedades magneticas de sistemas com eletrons fortemente correlacionados : MgB2 supercondutor, CaB6 semicondutor e, EuB6 semi-metalico ferromagnetico
Esta tese é o resultado da investigação de dois temas principais: o composto supercondutor MgB2 e o sistema semicondutor Ca1-xRxB6 dopado com terras raras R. O composto MgB2 é conhecido desde 1950, porém, só recentemente foi descoberto como sendo um supercondutor (tipo II) com uma temperatura crítica Tc @ 40 K. Esta descoberta realimentou o interesse
Publicado em: 2004
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7. ESTUDIO DE LA DISPERSIÓN CROMÁICA Y EFECTOS NO LINEALES EN FIBRAS DE DISPERSIÓN DESPLAZADA / STUDY OF CHROMATIC DISPERSION AND NONLINEAR EFFECTS IN SHIFTED DISPERSION FIBER OPTIC SYSTEM / ESTUDO DA DISPERSÃO CROMÁTICA E EFEITOS NÃO LINEARES EM FIBRAS DE DISPERSÃO DESLOCADA
This work presents a study on the mathematical determination of the total chromatic dispersion, zero dispersion wavelength and nonlinear optical effects in dispersion shifted (DS) fiber optic system. A methodology to determine the chromatic dispersion and zero dispersion wavelength is proposed using the equivalent step index model and the similarity of the t
Publicado em: 2001
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8. Espalhamento Raman dependente da temperatura no condutor superionico B-Eucrypte
By using Raman scattering techniques, we have studied the normal modes of vibration and the dynamics of the ionic motion in the superionic conductor b-Eucryptite, as a function of temperature, from room temperature to ~ 750ºC. Our results have proved that the high ionic conductivity it displays (~ 10-2 W-1cm-1, at 600ºC), can be explained in terms of the h
Publicado em: 1980
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9. Brillouin light scattering measurement of the elastic properties of aligned multilamella lipid samples
Brillouin measurements of the elastic properties are presented for aligned multilamella samples of both pure dipalmitoyl phosphatidylcholine at various temperatures and water concentrations and for the same compound containing 33 mol% cholesterol at various temperatures and two water concentrations. For pure dipalmitoyl phosphatidylcholine the elastic moduli
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10. Elasticity of MgO and a primary pressure scale to 55 GPa
We have studied the elasticity and pressure–density equation of state of MgO in diamond cells to 55 GPa and have doubled the previous pressure limit of accurate elasticity determinations for crystals. Integrating single-crystal velocity data from Brillouin scattering measurements and density data from polycrystalline x-ray diffraction, we obtained the
The National Academy of Sciences.