Adiabatic Pulses
Mostrando 1-6 de 6 artigos, teses e dissertações.
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1. Caracterização tectono-estratigráfica da sequência transicional na sub-bacia de Sergipe
This thesis deals with the tectonic-stratigraphic evolution of the Transitional Sequence in the Sergipe Sub-basin (the southern segment of the Sergipe-Alagoas Basin, Northeast Brazil), deposited in the time interval of the upper Alagoas/Aptian stage. Sequence boundaries and higher order internal sequences were identified, as well as the structures that affec
Publicado em: 2008
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2. "NMR imaging methodology using a single adiabatic inversion pulse." / "Metodologia de imagens de NMR que utiliza um único pulso adiabático de inversão."
Baseado em uma seqüência já conhecida de Multislice Spin Echo convencional, implementamos uma seqüência do tipo Modified Driven Equilibrium Fourier Transform (MDEFT) adiabática multislice em um sistema de 2T e um de microimagens (9.4T). Essa metodologia utiliza, como pulso de inversão, um pulso de RF com modulação em amplitude e freqüência, conhec
Publicado em: 2004
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3. Descrição analítica da magnetização induzida pela metodologia GMAX / Analytical description of the magnetization induced by the GMAX sequence
A metodologia GMAX, (Gradient-Modulated Adiabatic Excitation), caracteriza-se pelo uso de pulsos adiabáticos para localização de volumes em espectroscopia e seleção de fatias em MRI. A sua utilidade surge do interessante perfil de inversão da magnetização transversal induzido ao longo da amostra. Entretanto, a interpretação desse comportamento tem
Publicado em: 2003
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4. “Shim pulses” for NMR spectroscopy and imaging
A way to use adiabatic radiofrequency pulses and modulated magnetic-field gradient pulses, together constituting a “shim pulse,” for NMR spectroscopy and imaging is demonstrated. These pulses capitalize on phase shifts derived from probe gradient coils to compensate for nonlinear intrinsic main magnetic field homogeneity for spectroscopy, as well as for
National Academy of Sciences.
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5. Three-dimensional phase-encoded chemical shift MRI in the presence of inhomogeneous fields
A pulse sequence consisting of an excitation pulse and two adiabatic full-passage pulses with scaled relative peak amplitudes is combined with phase encoding to recover chemical shift information within 3D images in a 1D inhomogeneous static magnetic field with a matched rf field gradient. The results are discussed in the context of ex situ magnetic resonanc
National Academy of Sciences.
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6. FAST CARS: Engineering a laser spectroscopic technique for rapid identification of bacterial spores
Airborne contaminants, e.g., bacterial spores, are usually analyzed by time-consuming microscopic, chemical, and biological assays. Current research into real-time laser spectroscopic detectors of such contaminants is based on e.g., resonance fluorescence. The present approach derives from recent experiments in which atoms and molecules are prepared by one (
National Academy of Sciences.