Wave Breaking
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Efeitos de distribuição de carga na instabilidade de estados com partículas aprisionadas em Free-Electron Lasers
O free-electron laser (FEL) surgiu como uma nova fonte de radiação eletromagnética. O presente trabalho trata do efeito de carga em um FEL específico: de passagem única; e, sendo que as interações relevantes são entre o feixe e o campo magnético e entre os elétrons (não são estudados os campos auto consistentes do laser). Encontram-se as equaçõ
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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2. Waves in nuclear matter / Ondas na matéria nuclear
Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configu
Publicado em: 2009
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3. Ordem-desordem: uma avaliação estrutural do Ba(ZrxTi1-x)O3 / Order-disorder: an evaluation structural of Ba(ZrxTi1x)O3
This work have as aim, the synthesis of ceramic powders of Ba(ZrxTi1x)O3 (x = 0, 0.25, 0.50, 0.75 and 1) by the polymeric precursor method and investigate the degree of structural order-disorder of these systems by different characterization techniques, such as: thermogravimetric analysis (TA), differential thermal analysis (DTA), X-ray diffraction (XRD), Ra
Publicado em: 2009
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4. Quebra de simetria de cargas em estruturas eletrônicas blindadas
In this thesis, we will study the screening phenomenon in electronic structures based on a charge symmetry breaking model. For a Thomas-Fermi potential exp(qr)=r, this theory predicts that the nuclear charge , in the ground state of the screened Hydrogen atom, is degenerated ! (; ), giving rise to a dual charge in the electron wavefunction. In this
Publicado em: 2008
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5. Instrusion of the potential vorticity in the upper troposferic over south tropical atlantic and its relation with precipitation over NE of Brazil / Intrusão de vorticidade potencial na alta troposfera sobre o Atlântico tropical sul e sua relação com a precipitação no NE do Brasil
The Northeast Brazil (NEB) presents a great interannual variability of precipitation that can probably be explained by some atmospherics phenomenon of large scale. A system that can have some relationship with this variability is the intrusion event, characterised by Rossby wave breaking that provokes a connection between the tropical and extratropical regio
Publicado em: 2006
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6. VORTEX STATES IN UNCONVENTIONAL SUPERCONDUCTORS / ESTADOS DE VORTICES EM SUPERCONDUTORES NAO-CONVENCIONAIS
The theory of Bardeen, Cooper and Schrieffer (BCS) had great success in explaining most properties of superconducting materials. These materials, where BCS applies, are denominated conventional superconductors. the experimental evidence of unconventional superconductivity in several materials reopened discussions about the phenomenon. While, in conventional
Publicado em: 2002
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7. Espectroscopia Ãptica nÃo linear em sistemas atÃmicos envolvendo nÃveis de Rydberg
In this thesis we study nonlinear optical effects in alkali vapors, in which Rydberg levels play the role of near resonant intermediate levels, focusing our attention in processes such as: four wave mixing (FWM), two photon absorption, sum frequency generation (SF) and difference frequency generation (DF). We analyze a FWM process with two-photon transitions
Publicado em: 2002
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8. Wave energy and intertidal productivity
In the northeastern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Poste
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9. Precise tuning of barnacle leg length to coastal wave action.
Both spatial and temporal variation in environmental conditions can favour intraspecific plasticity in animal form. But how precise is such environmental modulation? Individual Balanus glandula Darwin, a common northeastern Pacific barnacle, produce longer feeding legs in still water than in moving water. We report here that, on the west coast of Vancouver I
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10. A simulation study of the effects of cardiac anatomy in ventricular fibrillation
In ventricular fibrillation (VF), the principal cause of sudden cardiac death, waves of electrical excitation break up into turbulent and incoherent fragments. The causes of this breakup have been intensely debated. Breakup can be caused by fixed anatomical properties of the tissue, such as the biventricular geometry and the inherent anisotropy of cardiac co
American Society for Clinical Investigation.
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11. Termination of spiral waves during cardiac fibrillation via shock-induced phase resetting
Multiple unstable spiral waves rotating around phase singularities (PSs) in the heart, i.e., ventricular fibrillation (VF), is the leading cause of death in the industrialized world. Spiral waves are ubiquitous in nature and have been extensively studied by physiologists, mathematicians, chemists, and biologists, with particular emphasis on their movement an
National Academy of Sciences.
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12. Membrane and acto-myosin tension promote clustering of adhesion proteins
Physicists have studied the aggregation of adhesive proteins, giving a central role to the elastic properties of membranes, whereas cell biologists have put the emphasis on the cytoskeleton. However, there is a dramatic lack of experimental studies probing both contributions on cellular systems. Here, we tested both mechanisms on living cells. We compared, f
National Academy of Sciences.