Magnetic Dipole
Mostrando 13-24 de 52 artigos, teses e dissertações.
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13. Operador dipolo-dipolo na base de momento angular: um complemento ao estudo de ressonância magnética nuclear
The relationship between the magnetic dipole-dipole potential energy function and its quantum analogue is presented in this work. It is assumed the reader is familiar with the classical expression of the dipolar interaction and has basic knowledge of the quantum mechanics of angular momentum. Except for these two points only elementary steps are involved.
Química Nova. Publicado em: 2008
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14. Microscopic theory of spin waves in magnetic nanowires / Teoria microscÃpica de ondas de spin em nanofios magnÃticos
The dynamical behavior of spins in magnetic materials is affected by its geometry and dimensionality. One can find several new results in the literature exploiting the magnetic properties of low dimension systems with different geometries, since the development of new devices such as: nanosensors, high density magnetic storage, etc., is closely related to ne
Publicado em: 2007
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15. Monte Carlo simulations of ultrathin magnetic dots
In this work we study the thermodynamic properties of ultrathin ferromagnetic dots using Monte Carlo simulations. We investigate the vortex density as a function of the temperature and the vortex structure in monolayer dots with perpendicular anisotropy and long-range dipole interaction. The interplay between these two terms in the hamiltonian leads to an in
Brazilian Journal of Physics. Publicado em: 2006-09
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16. Coherent properties and rabi oscillations in two-level donor systems
Coherent properties and Rabi oscillations in two-level donor systems, under terahertz excitation, are theoretically investigated. Here we are concerned with donor states in bulk GaAs and GaAs - (Ga, Al)As quantum dots. We study confinement effects, in the presence of an applied magnetic field, on the electronic and on-center donor states in GaAs - (Ga, Al)As
Brazilian Journal of Physics. Publicado em: 2006-06
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17. Construção de uma armadilha de dipolo com laser de CO2. / Constrution of a dipole trap using a CO2 laser
In this work we present the construction of an optical dipole trap using a CO2 laser, which involves the use of news and modern technologies never utilized by our group up to now. We have builded a new trap chamber with large optical access, used atomic dispensers as an atomic source and a high power CO2 laser and its optical components. We have demonstrated
Publicado em: 2006
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18. VÃrtices NÃo-Abelianos com Acoplamento NÃo-MÃnimo em um Background Gravitacional
The main purpose of this thesis is to investigate how the non-Abelian gauge symmetry affects the solutions of the equations of motion in some field theory models. We concern ourselves specifically with three dimensional field theories. We will note here that planar systems give us the needed informations about the theories approached here. Topological defect
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/07/2005
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19. Chiral bands in 105Rh
The 105Rh nucleus has been studied by in-beam gamma spectroscopy with the heavy-ion fusion-evaporation reaction 100Mo(11B, 02ngamma) at 43 MeV. A rich variety of structures was observed at high and low spin, using gamma - gamma - t and gamma - gamma - particle coincidences and directional correlation ratios. Four magnetic dipole band
Brazilian Journal of Physics. Publicado em: 2004-09
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20. Stochastic Molecular Dynamics of colloidal particles
Colloidal particles move in the carrier liquid under the action of several forces and torques. When the particles carry a dipole moment, electric or magnetic, as in ferrofluids, the rotational and translational motions are coupled because the field on a particle depends on the spatial and directional distribution of the others and the force and torque on it
Brazilian Journal of Physics. Publicado em: 2004-06
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21. The Ising model and real magnetic materials
The factors that make certain magnetic materials behave similarly to corresponding Ising models are reviewed. Examples of extensively studied materials include Dy(C2H5SO4)3.9H2) (DyES), Dy3Al5O12 (DyAlG), DyPO4, Dy2Ti2O7, LiTbF4, K2CoF4, and Rb2CoF4. Various comparisons between theory and experiment for these materials are examined. The agreement is found to
Brazilian Journal of Physics. Publicado em: 2000-12
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22. Estrutura nuclear e competição entre modos de decaimento de ressonancia gigantes
The low-lying leveI structure of the odd-mass Pb isotopes ( 193A205) is investigated in terms of the projected BCS approximation (PBCS) with one- and three- quasiparticle. A surface delta interaction (SDI) is used as residual interaction. Excitation energies, spectroscopic factors magnetic dipole and electric quadrupole moments are calculated and compared wi
Publicado em: 1997
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23. THE BUILDING OF A MAGNETOCARDIOGRAPHER AND PROPOSAL OF A MULTIPLE DIPOLE CARDIAC MODEL IN MAGNETOCARDIOGRAPHY / CONSTRUÇÃO DE UM MAGNETOCARDIÓGRAFO E PROPOSTA DE UM MODELO DE MÚLTIPLOS DIPOLOS EM MAGNETOCARDIOGRAFIA
Foi construído um magnetocardiógrafo supercondutor utilizando-se um SQUID (Superconductor Quantum Interference Device), capaz de medir campos magnéticos da ordem de 10 -8 gauss. Este aparelho foi utilizado para se testar a validade de um modelo cardíaco de múltiplos dipolos para magnetocardiografia. O modelo foi implementado através de um simulador el�
Publicado em: 1982
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24. Zero-quantum frequency-selective recoupling of homonuclear dipole-dipole interactions in solid state nuclear magnetic resonance
We describe a method for measuring magnetic dipole-dipole interactions, and hence distances, between pairs of like nuclear spins in a many-spin system under magic-angle spinning (MAS). This method employs a homonuclear dipolar recoupling sequence that creates an average dipole-dipole coupling Hamiltonian under MAS with full zero-quantum symmetry, including b
U.S. Government.