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Nuclear quadrupole resonance

About: Nuclear quadrupole resonance is a research topic. Over the lifetime, 3531 publications have been published within this topic receiving 38801 citations. The topic is also known as: Nuclear quadrupole resonance spectroscopy & NQR.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigated the structure of v -B 2 O 3 (v -B O 6 versus BO 3 ) by using MD simulations and found that the number of boron atoms in boroxol rings is higher in the structures generated with slow cooling than the predicted one of 80%.
Abstract: Several structural investigations using diffraction techniques, Raman spectroscopy, nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) have supported the idea that the structure of vitreous B 2 O 3 ( v -B 2 O 3 ) is built up predominantly by planar B 3 O 6 rings. Most Molecular Dynamics (MD) studies can be better understood by a continuous random network of BO 3 . In this work the structure of v -B 2 O 3 has been investigated by MD simulations. The magnitude of the differences in model density samples is studied as a function of the ratio of structural units (B 3 O 6 versus BO 3 ). The difference in this ratio in generated structures was obtained by two cooling cycles: Cycle I is simulating a quenched structure while the Cycle II intents to reproduce a slowly cooled structure. It is shown that for structures containing several hundred atoms MD simulations give a considerable variation for the ratio of building units. The computed density for the obtained structures could not reach experimental density values for either of the cooling cycles. The number of boron atoms in boroxol rings is higher in the structures generated with slow cooling but is less than the predicted one of 80%.

13 citations

Journal ArticleDOI
TL;DR: A 14N nuclear quadrupole resonance system designed to detect prohibited substances in the frequency range of 0.4–6 MHz, using low-power and frequency sweeping excitation and several technical solutions for noise reduction during data acquisition such as the use of fiber optic communication or battery-powered low-noise amplifier.

13 citations

Journal ArticleDOI
TL;DR: The temperature dependence of the 23NaOH pure quadrupole resonance (NQR) frequency has been studied from 77 to 550 K and shows a change in slope and a discontinuous change in frequency of 6±2 kHz at the orthorhombic to monoclinic phase transition at 505 K as mentioned in this paper.
Abstract: The temperature dependence of the 23NaOH pure quadrupole resonance (NQR) frequency has been studied from 77 to 550 K and shows a change in slope and a discontinuous change in frequency of 6±2 kHz at the orthorhombic to monoclinic phase transition at 505 K. At 292 K the 23Na NQR frequency is 1.778±0.001 MHz, η<0.04. The temperature dependence of the deuterium quadrupole coupling was fit to a librating molecule model between 293 and 570 K (QCC=245±2 kHz, η=0.05±0.01 at 293 K) and confirms that the frequency of the OD− libration decreases in the high temperature monoclinic phase.

13 citations

Journal ArticleDOI
TL;DR: The results of nuclear quadrupole resonance (NQR) studies of intramolecular complexes in halogen-containing organic compounds of metals of Group IVA are reviewed in this article.

13 citations

Proceedings ArticleDOI
09 Jul 2009
TL;DR: An overview of recent research in the detection of explosives using nuclear quadrupole resonance is presented and mathematical models for the data for different acquistion techniques are presented and various state of the art detection algorithms are evaluated.
Abstract: Nuclear quadrupole resonance (NQR) is a radio frequency spectroscopic technique that can be used to detect solid-state compounds containing quadrupolar nuclei, a requirement fulfilled by most high explosives (and narcotics). In this paper, we present an overview of recent research in the detection of explosives using this technique. We also present mathematical models for the data for different acquistion techniques and discuss different state of the art detection algorithms. Finally, we evaluate various algorithms on measured and simulated NQR data.

13 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202237
202116
202036
201928
201829