Generation and Application of Ultra-High-Intensity Magnetic Field Gradient Pulses for NMR Spectroscopy

Galvosas, Petrik; Stallmach, Frank; Seiffert, G.; Kärger, Jörg; Kaess, U.; Majer, G.

doi:10.1006/jmre.2001.2381

Cited by 154 publications

(103 citation statements)

References 26 publications

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“…Typische Parameter für 1 H-PFG-NMR-Untersuchungen mit der 13-Intervall-Pulsfolge am Spektrometer Fegris 400NT (400 MHz): [18] (908-1808)-HF-Pulsabstand t = 500 ms, Breite der gepulsten …”

Section: Experimentellesunclassified

NMR‐Untersuchungen zur Diffusion von Kohlenwasserstoffen im metall‐organischen Netzwerk MOF‐5

et al. 2006

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“…Typische Parameter für 1 H-PFG-NMR-Untersuchungen mit der 13-Intervall-Pulsfolge am Spektrometer Fegris 400NT (400 MHz): [18] (908-1808)-HF-Pulsabstand t = 500 ms, Breite der gepulsten …”

Section: Experimentellesunclassified

NMR‐Untersuchungen zur Diffusion von Kohlenwasserstoffen im metall‐organischen Netzwerk MOF‐5

et al. 2006

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“…Recent progress in the PFG NMR instrumentation and the thus obtained enhanced sensitivity have made it possible that today even in this short-time limit of PFG NMR more profound information may be deduced 18,19,24 .…”

Section: Short-time Limit Of the Effective Diffusivitymentioning

confidence: 99%

“…The diffusion measurements were carried out at a proton resonance frequency of 400 MHz (nhexane) and a fluorine resonance frequency of 376.4 MHz (tetrafluoromethane) using the home-built NMR spectrometer FEGRIS 400 NT 19 . The spectrometer is equipped with a ultrahigh intensity pulsed field gradient facility consisting of an actively shielded Anti-Helmholtz gradient coil and two Techron gradient current amplifiers connected in push-pullconfiguration 19 .…”

Section: Introductionmentioning

confidence: 99%

“…The spectrometer is equipped with a ultrahigh intensity pulsed field gradient facility consisting of an actively shielded Anti-Helmholtz gradient coil and two Techron gradient current amplifiers connected in push-pullconfiguration 19 . In order to circumvent the possibly disturbing influence of internal field gradients, the 13-interval pulse sequence with alterning pulsed field gradients was employed 20 .…”

Section: Introductionmentioning

confidence: 99%

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Boundary effects of molecular diffusion in nanoporous materials: A pulsed field gradient nuclear magnetic resonance study

Geier

Snurr

Stallmach

et al. 2004

The Journal of Chemical Physics

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ABSTARCTThe boundary conditions of intraparticle diffusion in nanoporous materials may be chosen to approach the limiting cases of either absorbing or reflecting boundaries, depending on the host-guest system under study and the temperature of measurement. Pulsed field gradient nuclear magnetic resonance (PFG NMR) is applied to monitor molecular diffusion of nhexane and of an n-hexane -tetrafluoromethane mixture adsorbed in zeolite crystallites of type NaX under either of these limiting conditions. Taking advantage of the thus established peculiarities of mass transfer at the interface between the zeolite bulk phase and the surrounding atmosphere, three independent routes for probing the crystal size are compared.These techniques are based on (i) the measurement of the effective diffusivity under complete confinement, (ii) the application of the so-called NMR tracer desorption technique and (iii) an analysis of the time dependence of the effective diffusivity in the short-time limit where, by an appropriate variation of the adsorbate and the measuring conditions, the limiting cases of reflecting and adsorbing boundaries could be considered. All these techniques are found to yield coinciding results, which are in excellent agreement with the crystal sizes determined by microscopy.2

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“…The magnet is a wide bore 9.4T superconducting type (Bruker, Germany) and is used with a MARAN ULTRA console (Resonance Instruments, GB) with a Direct Binary Coded Current Source [20] for gradient pulse generation, whilst the instrument is triggered at a constant mains voltage phase to avoid hum artefacts. Using a stimulated gradient echo sequence with compensation for a shift in echo position caused by imperfect gradient pulses [20], a sample volume of 0.5ml is tested in the actively shielded anti-helmholtz type probe at a range of temperatures for distilled water and gellan gum. These experiments allow rapid assessment of the stability of the preparation and its sensitivity to minor changes in temperature.…”

Section: P O S T P R I N T ( P R O O F C O P Y )mentioning

confidence: 99%

Robust spatially resolved pressure measurements using MRI with novel buoyant advection-free preparations of stable microbubbles in polysaccharide gels

Morris

Bencsik

Nestle

et al. 2008

Journal of Magnetic Resonance

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MRI of fluids containing lipid coated microbubbles has been shown to be an effective tool for measuring the local fluid pressure. However, the intrinsically buoyant nature of these microbubbles precludes lengthy measurements due to their vertical migration under gravity and pressure-induced coalescence. A novel preparation is presented which is shown to minimize both these effects for at least 25 minutes. By using a 2% polysaccharide gel base with a small concentration of glycerol and 1,2-Distearoyl-sn-Glycero-3-Phosphocholine coated gas microbubbles, MR measurements are made for pressures between 0.95 and 1.44 bar. The signal drifts due to migration and amalgamation are shown to be minimized for such an experiment whilst yielding very high NMR sensitivities up to 38% signal change per bar.

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Generation and Application of Ultra-High-Intensity Magnetic Field Gradient Pulses for NMR Spectroscopy

Cited by 154 publications

References 26 publications

NMR‐Untersuchungen zur Diffusion von Kohlenwasserstoffen im metall‐organischen Netzwerk MOF‐5

NMR‐Untersuchungen zur Diffusion von Kohlenwasserstoffen im metall‐organischen Netzwerk MOF‐5

Boundary effects of molecular diffusion in nanoporous materials: A pulsed field gradient nuclear magnetic resonance study

Robust spatially resolved pressure measurements using MRI with novel buoyant advection-free preparations of stable microbubbles in polysaccharide gels

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