Extraction of dipolar coupling constants from low-frequency electrically detected magnetic resonance and near-zero field magnetoresistance spectra via least squares fitting to models developed from the stochastic quantum Liouville equation

2021 ◽  
Vol 130 (23) ◽  
pp. 234401
Author(s):  
Elias B. Frantz ◽  
Nicholas J. Harmon ◽  
David J. Michalak ◽  
Eric M. Henry ◽  
Michael E. Flatté ◽  
...  
1989 ◽  
Vol 67 (3) ◽  
pp. 454-459 ◽  
Author(s):  
William P. Power ◽  
Roderick E. Wasylishen ◽  
Ronald D. Curtis

Simultaneous observation of anisotropic chemical shielding and dipolar coupling in polycrystalline monophosphazenes has been used to obtain information on the 31P–14N spin pair. Phosphorus-31 chemical shielding tensor components have been determined; the most shielded component was found to lie along the P=N bond. The 31P–14N dipolar coupling constants have provided P=N bond lengths from powder samples, equivalent for all compounds within experimental error; the value obtained for N–(triphenylphosphoranylidene)-aniline is in excellent agreement with that obtained in a recent X-ray diffraction study. Features of crystallographic significance have been determined from the solid-state nuclear magnetic resonance spectra for two of the compounds without resorting to diffraction techniques. Information on the magnitude and orientation of the 14N electric field gradient tensor has been inferred from 31P MAS spectra and abinitio calculations. Keywords: monophosphazenes, dipolar nmr, 31P chemical shielding anisotropies, solid-state nmr.


1988 ◽  
Vol 89 (11) ◽  
pp. 6623-6635 ◽  
Author(s):  
R. Kreis ◽  
A. Thomas ◽  
W. Studer ◽  
R. R. Ernst

2018 ◽  
Vol 41 (5) ◽  
pp. 1458-1467 ◽  
Author(s):  
Shizeng Lu ◽  
Hongliang Yu ◽  
Xiaohong Wang

The steady-state detection of burning flame temperature plays an important role in the modelling, state identification and optimization control of the cement clinker burning process. In this paper, the steady-state detection method of burning flame temperature based on wavelet transform and least squares method is studied. First, the burning flame temperature data were detected accurately using a video detection device. Then, the temperature signal was decomposed into the high-frequency and low-frequency components based on the wavelet transform method, and the wavelet basis function and the decomposition layer were determined by least squares fitting error. Thus, the signal trend item can be obtained by removing the high-frequency component that represents the signal noise, and reconstructing the low-frequency component that reflects the basic trend of the signal. On this basis, the first derivative of the trend was further obtained, and the steady-state detection threshold was set to achieve steady state-detection of the burning flame temperature. The results showed that the method proposed in this paper can accurately extract the burning flame temperature trend and realize steady-state detection. This paper provides a feasible method for the steady-state detection of burning temperature.


2020 ◽  
Author(s):  
Dudari B. Burueva ◽  
James Eills ◽  
John W. Blanchard ◽  
Antoine Garcon ◽  
Román Picazo Frutos ◽  
...  

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>


2020 ◽  
Vol 67 (7) ◽  
pp. 1669-1673
Author(s):  
Nicholas J. Harmon ◽  
Stephen R. Mcmillan ◽  
James P. Ashton ◽  
Patrick M. Lenahan ◽  
Michael E. Flatte

2021 ◽  
Vol 130 (6) ◽  
pp. 065701
Author(s):  
Elias B. Frantz ◽  
David J. Michalak ◽  
Nicholas J. Harmon ◽  
Eric M. Henry ◽  
Stephen J. Moxim ◽  
...  

2020 ◽  
Author(s):  
Dudari B. Burueva ◽  
James Eills ◽  
John W. Blanchard ◽  
Antoine Garcon ◽  
Román Picazo Frutos ◽  
...  

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>


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