The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform

Geoffrey Bodenhausen - One of the best experts on this subject based on the ideXlab platform.

  • broadband Decoupling in nmr with frequency modulated chirp pulses
    Chemical Physics Letters, 1995
    Co-Authors: Riqiang Fu, Geoffrey Bodenhausen
    Abstract:

    In NMR of spins with I = 1/2 in an isotropic phase, it is demonstrated by simulation and expt. that virtually unlimited bandwidths can be decoupled effectively by using chirp pulses with linear frequency modulation for adiabatic inversion combined with phase-cycles and supercycles similar to those used in composite pulse Decoupling. The av. radio-frequency amplitude required is modest compared to other techniques. In applications with inhomogeneous radio-frequency fields, as in magnetic resonance imaging and localized spectroscopy with surface coils, the radio-frequency amplitude can be apodized at the rising and falling edges of chirp pulses to improve adiabatic behavior. [on SciFinder (R)]

Riqiang Fu - One of the best experts on this subject based on the ideXlab platform.

  • broadband Decoupling in nmr with frequency modulated chirp pulses
    Chemical Physics Letters, 1995
    Co-Authors: Riqiang Fu, Geoffrey Bodenhausen
    Abstract:

    In NMR of spins with I = 1/2 in an isotropic phase, it is demonstrated by simulation and expt. that virtually unlimited bandwidths can be decoupled effectively by using chirp pulses with linear frequency modulation for adiabatic inversion combined with phase-cycles and supercycles similar to those used in composite pulse Decoupling. The av. radio-frequency amplitude required is modest compared to other techniques. In applications with inhomogeneous radio-frequency fields, as in magnetic resonance imaging and localized spectroscopy with surface coils, the radio-frequency amplitude can be apodized at the rising and falling edges of chirp pulses to improve adiabatic behavior. [on SciFinder (R)]

Mark Rance - One of the best experts on this subject based on the ideXlab platform.

  • suppression of the effects of cross correlation between dipolar and anisotropic chemical shift relaxation mechanisms in the measurement of spin spin relaxation rates
    Molecular Physics, 1992
    Co-Authors: Arthur G Palmer, Nicholas J Skelton, Walter J Chazin, Peter E Wright, Mark Rance
    Abstract:

    Cross correlation between dipolar and anisotropic chemical shift relaxation mechanisms complicates measurements of heteronuclear spin-spin relaxation rate constants by the Carr-Purcell-Meiboom-Gill (CPMG) technique if the magnitudes of the chemical shift anisotropy and the dipolar interaction are comparable. Experimental schemes are described that attenuate the effects of cross correlation and permit accurate measurements of spin-spin relaxation rate constants for heteronuclei with significant chemical shift anisotropies. The theoretical analysis is confirmed by measurements of 15N and 13C spin-spin relaxation in a peptide. Application of 180° pulses to the protons directly attached to the heteronuclei in synchrony with the even echoes of the heteronuclear spins yields more accurate results than continuous irradiation of the protons with a composite pulse Decoupling sequence or application of a single 180° pulse to the protons in the middle of the CPMG pulse train.

Arthur G Palmer - One of the best experts on this subject based on the ideXlab platform.

  • suppression of the effects of cross correlation between dipolar and anisotropic chemical shift relaxation mechanisms in the measurement of spin spin relaxation rates
    Molecular Physics, 1992
    Co-Authors: Arthur G Palmer, Nicholas J Skelton, Walter J Chazin, Peter E Wright, Mark Rance
    Abstract:

    Cross correlation between dipolar and anisotropic chemical shift relaxation mechanisms complicates measurements of heteronuclear spin-spin relaxation rate constants by the Carr-Purcell-Meiboom-Gill (CPMG) technique if the magnitudes of the chemical shift anisotropy and the dipolar interaction are comparable. Experimental schemes are described that attenuate the effects of cross correlation and permit accurate measurements of spin-spin relaxation rate constants for heteronuclei with significant chemical shift anisotropies. The theoretical analysis is confirmed by measurements of 15N and 13C spin-spin relaxation in a peptide. Application of 180° pulses to the protons directly attached to the heteronuclei in synchrony with the even echoes of the heteronuclear spins yields more accurate results than continuous irradiation of the protons with a composite pulse Decoupling sequence or application of a single 180° pulse to the protons in the middle of the CPMG pulse train.

Glaser, Steffen J. - One of the best experts on this subject based on the ideXlab platform.

  • Next‐Generation Heteronuclear Decoupling for High‐Field Biomolecular NMR Spectroscopy
    SelectedWorks, 2019
    Co-Authors: Schilling Franz, Warner, Lisa R., Gershenzon Naum, Skinner, Thomas E., Sattler Michael, Glaser, Steffen J.
    Abstract:

    Ultra‐high‐field NMR spectroscopy requires an increased bandwidth for heteronuclear Decoupling, especially in biomolecular NMR applications. Composite pulse Decoupling cannot provide sufficient bandwidth at practical power levels, and adiabatic pulse Decoupling with sufficient bandwidth is compromised by sideband artifacts. A novel low‐power, broadband heteronuclear Decoupling pulse is presented that generates minimal, ultra‐low sidebands. The pulse was derived using optimal control theory and represents a new generation of Decoupling pulses free from the constraints of periodic and cyclic sequences. In comparison to currently available state‐of‐the‐art methods this novel pulse provides greatly improved Decoupling performance that satisfies the demands of high‐field biomolecular NMR spectroscopy