Wave-induced plasma transport in the magnetic drift frequency range

1985 ◽  
Vol 28 (2) ◽  
pp. 538 ◽  
Author(s):  
M. Rosenberg ◽  
N. A. Krall ◽  
J. B. McBride
Keyword(s):  
Plasma Transport ◽  
Frequency Range ◽  
Drift Frequency ◽  
Wave Induced

On wave-induced stress in a ship executing symmetric motions

1973 ◽  
Vol 275 (1247) ◽  
pp. 1-32 ◽  
Keyword(s):  
Natural Vibration ◽  
Bending Moment ◽  
Natural Vibration Frequency ◽  
Frequency Range ◽  
Induced Stress ◽  
Head Waves ◽  
Rational Explanation ◽  
Different Response ◽  
Wave Matching ◽  
Wave Induced

The equation of motion of a simple beam in head waves is solved in terms of modal responses. Examination of the resulting expression for wave-induced bending moment indicates that at lower wave frequencies large fluctuating stresses are generally associated with 'ship-wave matching', a phenomenon governed by the relative geometry of ship and wave; whereas large stresses in the higher frequency range are the result of 'resonant encounter' during which the encounter frequency of ship with wave corresponds to a natural vibration frequency of the ship as a beam. The contrasting characteristics of these different response mechanisms are shown to provide a rational explanation of the fluctuating stresses induced in large or flexible ships in confused seas.

scholarly journals Variations of Helicon Wave-induced Radial Plasma Transport in Different Experimental Conditions

1994 ◽  
Vol 47 (3) ◽  
pp. 315 ◽  
Author(s):  
V Petržílka
Keyword(s):  
Plasma Density ◽  
Plasma Transport ◽  
Plasma Confinement ◽  
Experimental Conditions ◽  
Magnetostatic Field ◽  
Directed Transport ◽  
Helicon Wave ◽  
Transport Velocity ◽  
Plasma Radius ◽  
Wave Induced

Variations of the helicon wave-induced radial plasma transport are presented depending on values of the plasma radius, magnetostatic field, plasma density and the frequency of the helicon wave. It is shown that the value of the helicon wave-induced transport may be significant for plasma confinement; this is demonstrated, for the experiments BASIL and SHEILA. Whereas m = +1 helicons induce an inward-directed transport and thus improve the confinement, m = -1 helicons induce an outward-directed transport velocity.

Remote launching of plasma modes in the drift frequency range

1997 ◽  
Vol 39 (3) ◽  
pp. 367-374 ◽  
Author(s):  
V V Abrakov ◽  
A Ye Petrov ◽  
K A Sarksyan ◽  
N N Skvortsova ◽  
C Hidalgo ◽  
...  
Keyword(s):  
Frequency Range ◽  
Drift Frequency

The mode transition process in collisional drift waves and self-consistent plasma diffusion across a magnetic field

1977 ◽  
Vol 55 (15) ◽  
pp. 1356-1359 ◽  
Author(s):  
R. Jones
Keyword(s):  
Magnetic Field ◽  
Transition Process ◽  
Plasma Transport ◽  
Drift Waves ◽  
Mode Transition ◽  
Linear Mode ◽  
Drift Wave ◽  
Self Consistent ◽  
Plasma Diffusion ◽  
Wave Induced

Drift wave induced cross field plasma transport is observed to destabilize new drift instabilities which then act to quench the original linear mode and enhance diffusion.

On helicon wave induced radial plasma transport

1993 ◽  
Vol 43 (12) ◽  
pp. 1203-1211 ◽  
Author(s):  
V. Petržílka
Keyword(s):  
Plasma Transport ◽  
Helicon Wave ◽  
Wave Induced

Density-based discrimination of protein and RNA in the ribosome

1992 ◽  
Vol 50 (1) ◽  
pp. 464-465
Author(s):  
Joachim Frank
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Dark Field Image ◽  
Dark Field ◽  
Frequency Range ◽  
Bright Field ◽  
Contrast Transfer Function ◽  
Pass Filter

Cryo-electron microscopy combined with single-particle reconstruction techniques has allowed us to form a three-dimensional image of the Escherichia coli ribosome.In the interior, we observe strong density variations which may be attributed to the difference in scattering density between ribosomal RNA (rRNA) and protein. This identification can only be tentative, and lacks quantitation at this stage, because of the nature of image formation by bright field phase contrast. Apart from limiting the resolution, the contrast transfer function acts as a high-pass filter which produces edge enhancement effects that can explain at least part of the observed variations. As a step toward a more quantitative analysis, it is necessary to correct the transfer function in the low-spatial-frequency range. Unfortunately, it is in that range where Fourier components unrelated to elastic bright-field imaging are found, and a Wiener-filter type restoration would lead to incorrect results. Depending upon the thickness of the ice layer, a varying contribution to the Fourier components in the low-spatial-frequency range originates from an “inelastic dark field” image. The only prospect to obtain quantitatively interpretable images (i.e., which would allow discrimination between rRNA and protein by application of a density threshold set to the average RNA scattering density may therefore lie in the use of energy-filtering microscopes.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

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