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Adiabatic MRI Pulses
Adiabatic radio frequency (RF) pulses are used in magnetic resonance imaging (MRI) to achieve excitation that is insensitive to spatial inhomogeneities in the excitation field or off-resonances in the sampled object. Nuclear magnetic resonance (NMR) experiments are often performed with surface transceiver coils that have desirable sensitivity, but have the disadvantage of producing an inhomogeneous excitation field. This inhomogeneous field causes spatial variations in spin flip angles, which, in turn, causes errors and degrades the receiver’s sensitivity. RF pulses can be designed to create low-variation flip-angles or uniform magnetization inversion across a sample, even in the presence of inhomogeneities such as B1-variation and off-resonance. Analysis - Adiabatic Excitation Principles Traditional RF Excitation In traditional MRI RF excitation, an RF pulse, B1, is applied with a frequency that is resonant with the nutation frequency of the spins of interest. In the frame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperbolic Secant Adiabatic Pulse Progression
Hyperbolic is an adjective describing something that resembles or pertains to a hyperbola (a curve), to hyperbole (an overstatement or exaggeration), or to hyperbolic geometry. The following phenomena are described as ''hyperbolic'' because they manifest hyperbolas, not because something about them is exaggerated. * Hyperbolic angle, an unbounded variable referring to a hyperbola instead of a circle * Hyperbolic coordinates, location by geometric mean and hyperbolic angle in quadrant I * Hyperbolic distribution, a probability distribution characterized by the logarithm of the probability density function being a hyperbola * Hyperbolic equilibrium point, a fixed point that does not have any center manifolds * Hyperbolic function, an analog of an ordinary trigonometric or circular function * Hyperbolic geometric graph, a random network generated by connecting nearby points sprinkled in a hyperbolic space * Hyperbolic geometry, a non-Euclidean geometry * Hyperbolic group, a fin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweep Diagram For Hyperbolic Secant Pulse
Sweep or swept may refer to: Cleaning * Sweep, the action of using a brush to clean * Chimney sweep, a worker who clears ash and soot from chimneys * Street sweeper, a person's occupation, or a machine that cleans streets * Swept quartz, a cleaning of quartz crystal from alkali metal ions Arts, entertainment, and media * ''Sweep'' (book series), a fictional series by Cate Tiernan * Sweep (puppet), a character on the British children's television series ''The Sooty Show'' * Sweep, an ability keyword in '' Magic: The Gathering'' * Sweep-picking, a guitar technique * Sweeps period, a system of calculating viewership for television programming * ''Swept'' (album), a 1991 album by the English singer Julia Fordham Detection * Bug sweeping, the common name for electronic counter surveillance * Minesweeper (ship), a small naval ship designed to engage in minesweeping * Minesweeping, the practice of removing explosive mines * Radio-frequency sweep, the action of scanning a radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
