منابع مشابه
Broadband population inversion in solid state NMR
We present theory, simulations and experimental demonstrations of composite 1T pulses for population inversion in coupled spin systems such as occur in solid state NMR. The composite 1T pulses are phase-shifted rf pulse sequences designed to invert spins over a larger range of dipole or quadrupole couplings than a conventional1T pulse, for a given rfpower. We discuss a previously proposed theor...
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A typical geoacoustic inversion procedure involves powerful source transmissions received on a large-aperture receiver array. A more practical approach is to use a single moving source and/or receiver in a low signal to noise ratio (SNR) setting. This paper uses single-receiver, broadband, frequency coherent matched-field inversion and exploits coherently repeated transmissions to improve estim...
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New NMR broadband inversion pulses that compensate both for resonance offset and radiofrequency (RF) inhomogeneity are described. The approach described is a straightforward computer optimization of an initial digitized waveform generated from either a constant-amplitude frequency sweep or from an existing composite inversion pulse. Problems with convergence to local minima are alleviated by th...
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Received (to be inserted Revised by Publisher) Matched eld acoustic inversion techniques were investigated using data from sparsely populated vertical receiving arrays and a single receiver element. The purpose of considering sparse data sets is to investigate, under simulation, the feasibility of reducing the number and complexity of acoustic measurements needed for geo{acoustic inversion. The...
متن کاملPopulation inversion by chirped pulses
In this paper, we analyze the condition for complete population inversion by a chirped pulse over a finite duration. The nonadiabatic transition probability is mapped in the two-dimensional parameter space of coupling strength and detuning amplitude. Asymptotic forms of the probability are derived by the interference of nonadiabatic transitions for sinusoidal and triangular pulses. The qualitat...
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ژورنال
عنوان ژورنال: Physical Review Letters
سال: 1983
ISSN: 0031-9007
DOI: 10.1103/physrevlett.51.775