Eigenmodes
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Stability of the envelope evolution of a cold-fluid corkscrewing elliptic beam in a uniform-focusing magnetic field
The envelope oscillations of a cold-fluid corkscrewing elliptic beam in a uniform-focusing magnetic field are studied. In particular, by linearizing the generalized beam envelope equations, the eigenmodes of small-amplitude envelope oscillations are calculated for a cold-fluid corkscrewing elliptic beam oscillating about its equilibrium. All of the eigenmode
Publicado em: 2011
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2. On asymptotic analysis of spectral problems in elasticity
The three-dimensional spectral elasticity problem is studied in an anisotropic and inhomogeneous solid with small defects, i.e., inclusions, voids, and microcracks. Asymptotics of eigenfrequencies and the corresponding elastic eigenmodes are constructed and justified. New technicalities of the asymptotic analysis are related to variable coefficients of diffe
Latin American Journal of Solids and Structures. Publicado em: 2011
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3. Projeto de transdutores baseados em placas piezelétricas através do método de otimização topológica. / Design of transducers based on piezoelectric plates by using the topology optimization method.
Sensores e atuadores baseados em placas piezelétricas têm apresentado uma crescente demanda no campo denominado Estruturas Inteligentes, incluindo o desenvolvimento de atuadores para aplicações de resfriamento e bombeamento de fluidos, transdutores para novos coletores de energia, e diversas outras aplicações que apresentem requisitos quasi -estáticos
Publicado em: 2011
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4. Microlasers de cavidades estadio aplicados a detecção nanovolumetrica / Stadium cavities microlasers applied to the nanovolumetric detection
This work presents the development of resonant cavities based on chaotic billiard geometries built with semiconductor active optical medium for sensing applications. In spite of the classically chaotic behavior of the stadium, the quantum description of the problem in the semi-classical limit shows unexpected accumulations of the density of probability on cl
Publicado em: 2010
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5. ANÁLISE DE ESTABILIDADE DE ESCOAMENTOS VISCOSOS E VISCOELÁSTICOS / LINEAR STABILITY ANALYSIS OF VISCOUS AND VISCOELASTIC FLOWS
Steady state,two-dimensional flows may become unstable under two and three-dimensional disturbances, if the flow parameters exceed some critical values. In many practical situations, determining the parameters at which the flow becomes unstable is essential. The complete understanding of viscous and viscoelastic flows requires not only the steady state solut
Publicado em: 2007
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6. The sinusoid as the longitudinal profile in backward-wave oscillators of large cross sectional area
High-power generation in backward-wave oscillators (BWO) of large section requires that the beam electrons flowing close to the corrugated wall interact efficiently with surface waves supported by a periodic structure. Such waves are described by the superposition of slow-wave space harmonics of the operating mode. The present paper reports on design tools f
Brazilian Journal of Physics. Publicado em: 2004-12
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7. Ordem e caos em plasmas magnetizados
The objective of this thesis is to present a clear understanding of some important nonlinear phenomena that are common in space and laboratory plasmas. Specifically,the present analytical and numerical studies have focused on the properties of electromagnetic turbulence as well as associated coherent structures and chaotic behaviors in a multi-component magn
Publicado em: 1999
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8. Measurement of erythrocyte membrane elasticity by flicker eigenmode decomposition.
We have studied the flickering of erythrocytes at wavelengths comparable to the cell dimension. To do this we have analyzed the edge fluctuations of the cell to a resolution of 5 nm by combining phase contrast microscopy with fast image processing. By measuring the edge excitations simultaneously at four orthogonal positions around the cell, the eigenmodes o
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9. Harmonic vibrations and thermodynamic stability of a DNA oligomer in monovalent salt solution.
We compute the full harmonic vibrational spectrum and eigenmodes of a DNA oligomer, d(C-G)3, in optimized B and Z conformations in various ionic environments (0.01-5.0 M NaCl). The statistical interactions of DNA with the diffuse ionic cloud surrounding it in solution are approximately represented within the potential of mean force framework. The lowest eige
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10. Analysis of flow-structure interaction in the larynx during phonation using an immersed-boundary method
A recently developed immersed-boundary method is used to model the flow-structure interaction associated with the human phonation. The glottal airflow is modeled as a two-dimensional incompressible flow driven by a constant subglottal pressure, and the vocal folds are modeled as a pair of three-layered, two-dimensional, viscoelastic structures. Both the flui
Acoustical Society of America.
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11. Stable relativistic/charge-displacement channels in ultrahigh power density (≈1021 W/cm3) plasmas
Robust stability is a chief characteristic of relativistic/charge-displacement self-channeling. Theoretical analysis of the dynamics of this stability (i) reveals a leading role for the eigenmodes in the development of stable channels, (ii) suggests a technique using a simple longitudinal gradient in the electron density to extend the zone of stability
The National Academy of Sciences.
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12. RNA hairpin-folding kinetics
Based on the complete ensemble of hairpin conformations, a statistical mechanical model that combines the eigenvalue solutions of the rate matrix and the free-energy landscapes has been able to predict the temperature-dependent folding rate, kinetic intermediates, and folding pathways for hairpin-forming RNA sequences. At temperatures higher than a “glass
The National Academy of Sciences.