Spectral Theory
Mostrando 13-24 de 100 artigos, teses e dissertações.
-
13. Structural characterization from empirical modeling and GRART model evaluation in the Eucalyptus spp. canopies spectral characterization / Caracterização estrutural a partir de modelos empíricos e avaliação do modelo GRART na caracterização espectral de dosséis de Eucalyptus spp
Empirical modeling and models based on transfer theory have been applied to estimate quantitative information from spectral data and from their relationships with canopy biophysical parameters. Both modeling strategies have been explored here in order to estimate structural and spectral information from extit{Eucalyptus} spp. (eucalipto) canopies. Correlati
Publicado em: 2010
-
14. Desempenho de codigo turbo quaternario em sistemas de multiplexação por divisão de frequencias ortogonais / Performance of quaternary turbo codes in orthogonal frequency division multiplex systems
This study evaluates the performance of quaternary turbo codes, with generator matrix G = [7, 5] for the constituent convolutional codes and s-random interleaving , in an OFDM transmission system. This performance is measured in terms of bit error rate versus energy per bit to unilateral noise power spectral density ratio. The results obtained are analyzed c
Publicado em: 2010
-
15. Estudo da microcirculação na hanseníase virchowiana com o uso da microscopia de luz ortogonal polarizada e com laser-doppler fluxometria / Microcirculation s research in leprosy with orthogonal polarization special imaging and laser doppler
Leprosy is an infectious disease with unique characteristics. One of them is the fact that it compromises not only the cutaneous and adnexial innervation, but also the innervation of the cutaneous microcirculation. Several articles indicate the impact of disautonomy on the microcirculatory level, citing the example of changes in vasomotor level. The present
Publicado em: 2010
-
16. Reconstrução intranodal da solução numérica gerada pelo método espectronodal constante para problemas Sn de autovalor em geometria retangular bidimensional / Nodal reconstruction scheme for the numerical solution generated by the constant spectral nodal method for Sn eingenvalue problem in X, Y geometry
In this dissertation the spectral nodal method SD-SGF-CN, cf. spectral diamond spectral Green s function - constant nodal, is used to determine the angular fluxes averaged along the edges of the homogenized nodes in heterogeneous domains. Using these results, we developed an algorithm for the reconstruction of the node-edge average angular fluxes within the
Publicado em: 2009
-
17. Existencia e estabilidade de ondas viajantes periodicas para alguns modelos dispersivos / Existence and stability of periodic travelling waves for some dispersive models
The goal of this thesis is to study the properties of solutions of some dispersive differential equations. First, we develop a local and global well-posedness theory for the regularized Benjamin-Ono equation in the periodic setting, then, we show that the Cauchy problem for this equation (in both periodic and nonperiodic cases) cannot be solved by an iterati
Publicado em: 2009
-
18. Synthesis, characterization, DFT and Td-dfT study of the [Fe(mnt)(L)(t-BuNC) 2] octahedral complex (L = phen, bipy)
FeBr2 has reacted with an equivalent of mnt2- (mnt = cis-1,2-dicyanoethylene-1,2-dithiolate) and the α-diimine L (L = 1,10'-phenantroline, 2,2'-bipyridine) in THF solution, and followed by adding of t-butyl-isocyanide to give [Fe(mnt)(L)(t-BuNC)2] neutral compound. The products were characterized by infrared, UV-visible and Mössbauer spectroscopy, besides
Química Nova. Publicado em: 2009
-
19. Spectroscopies of photoluminescence and excitation of MgGa2O4 samples doped with Mn2+. / Espectroscopia de fotoluminescência e excitação de amostras MgGa2O4 dopadas com Mn2+
This work presents the room temperature photoluminescence and excitation spectroscopes data of MgGa2O4 samples doped with 0.5% and 10.0% Mn2+. The polycrystalline samples were produced by solid-state reaction at high temperature and characterized with X ray Diffraction and SEM. The photoluminescence spectra showed emission at green and red spectral regions,
Publicado em: 2009
-
20. Descrição acústica dos sons vocálicos anteriores do inglês e do português realizados por professores de inglês língua estrangeira no Oeste Potiguar / Description of the acoustic vowel sounds of English and previous made by the Portuguese teachers of English language foreign in the West Potiguar
The study acoustically compared Brazilian Portuguese (BP) front vowels to similar sounds found in the English as a Foreign Language (EFL) as realized by teachers of English in western Rio Grande do Norte. We analized PB [i, e, E] and EFL [i, I, E, Q], as well as the diphthong [eI] in both languages. In order to ground our research theoretically, we made use
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/08/2008
-
21. High temperature Raman spectra of L-leucine crystals
Single crystal samples of L-leucine, C6H13NO2, a fundamental aliphatic amino acid of the human body, have been studied by Raman spectroscopy at temperatures from 300 to 430 K over the spectral range from 50 to 3100 cm-1. A tentative assignment of all bands is given. For high temperatures, several modifications on the Raman spectra were observed at about 353
Brazilian Journal of Physics. Publicado em: 2008-03
-
22. Comportamento assintótico para soluções de certas equações diferenciais funcionais periódicas / Asymptotic behavior of solutions to certain periodic functional differential equations
We are interested in the study of the asymptotic behavior of the solutions of a class of linear autonomous Functional Differential Equations (FDE) of neutral type, where the coeficients of the non neutral part are periodic functions with common period w and the time delays are multiples of w. We employ the spectral theory for linear operators applied to the
Publicado em: 2008
-
23. THE HOMOLOGY OF SOME ISOSPECTRAL MANIFOLDS / HOMOLOGIA DE VARIEDADES ISOESPECTRAIS
For (Lambda) a real, diagonal matrix of simple spectrum, we consider O(lambda), the isospectral manifold of real, symmetric matrices conjugate to (Lambda), and (Tau)(Lambda), the isospectral manifold of tridiagonal matrices in O(Lambda).We compute the homologies of both manifolds, combining techniques of Morse theory and integrable systems. As a consequence,
Publicado em: 2008
-
24. A dinamica por tras da sequencia espectral / The dynamic behind the spectral sequence
In this work, we present an algorithm for a chain complex C and its di_erential given by a connection matrix which determines an associated spectral sequence (Er, dr). More specifically, a system spanning Er in terms of the original basis of C is obtained as well as the identi_cation of all di_erentials dr p : Er p ! Er p?r. In exploring the dynamical implic
Publicado em: 2008