The determination of the electron density distribution of an ionosphere layer in the presence of an external magnetic field

1954 ◽  
Vol 5 (1-6) ◽  
pp. 11-27 ◽  
Author(s):  
John M. Kelso
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution

scholarly journals High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

IUCrJ ◽  
2016 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
E. I. Howard ◽  
B. Guillot ◽  
M. P. Blakeley ◽  
M. Haertlein ◽  
M. Moulin ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Fatty Acid ◽  
High Resolution ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Room Temperature ◽  
Water Molecules ◽  
X Ray

Crystal diffraction data of heart fatty acid binding protein (H-FABP) in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively). These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA) binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium) positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

The electron density distribution in the topside ionosphere I. Magnetic-field-alined strata

1964 ◽  
Vol 281 (1387) ◽  
pp. 450-458 ◽  
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Probe ◽  
Electron Density Distribution ◽  
Topside Ionosphere ◽  
Electric Permittivity ◽  
Measuring Head ◽  
Flat Disk ◽  
Method Of Measurement

1. The method of measurement of electron density The measurement of the electron density distribution in the topside ionosphere is made by a radio-frequency electron probe which was developed for this satellite. This probe measures the local electric permittivity of the medium in the vicinity of the satellite using a probing frequency of 10 Mc/s and from a knowledge of the permittivity the electron density is readily calculated. The electrodes consist of a pair of flat disk-shaped grids, 4 in. in diameter and spaced 3 1|2 in. apart. These grids are supported on the ends of two short tubes which, in turn, are mounted on a small junction box. This complete unit, which forms the measuring head, is fixed on the end of a retractable boom which extends about 3 ft. from the hull of the satellite. The permittivity is measured in terms of the current that flows between the two electrodes in response to a constant applied signal of 3 V r.m.s. This signal is provided by a 10 Mc/s crystal controlled oscillator, the amplitude being electronically stabilized at the above value.

Modelling the Electron Density Distribution in the July 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 535-539 ◽  
Author(s):  
F. Clette ◽  
P. Cugnon ◽  
J.-R. Gabryl
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Legendre Polynomials ◽  
Electron Density Distribution ◽  
Large Scale ◽  
Symmetry Axis ◽  
Rotation Axis ◽  
Magnetic Field Axis ◽  
The Mean

AbstractUsing intensity and polarization maps computed from white-light observations of the July 11, 1991 solar eclipse, we present axisymmetrical models of the large-scale electron density distribution in the corona. These models are based on an expansion in Legendre polynomials, and are flexible enough to fit individual features, like streamers and holes. Furthermore, as the symmetry axis of our models can take any orientation, we consider two plausible configurations, aligned on the rotation axis or the mean bipolar magnetic field axis. Their respective abilities to reproduce a strongly non-spherical global magnetic structure are then compared.

Electron-density distribution in CuFeS2 as determined by 63,65Cu NMR in an internal magnetic field

2013 ◽  
Vol 80 (3) ◽  
pp. 351-356 ◽  
Author(s):  
A. I. Pogoreltsev ◽  
A. N. Gavrilenko ◽  
V. L. Matukhin ◽  
B. V. Korzun ◽  
E. V. Schmidt
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Internal Magnetic Field
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