Anomalous Acoustic Dispersion in Centrosymmetric Crystals with Soft Optic Phonons

1970 ◽  
Vol 1 (3) ◽  
pp. 1227-1234 ◽  
Author(s):  
J. D. Axe ◽  
J. Harada ◽  
G. Shirane
Keyword(s):  
Acoustic Dispersion

Dispersion relations, rays and ray splitting in magnetohelioseismology

2005 ◽  
Vol 364 (1839) ◽  
pp. 333-349 ◽  
Author(s):  
P.S Cally
Keyword(s):  
Strong Field ◽  
Mode Conversion ◽  
Low Frequency ◽  
Active Regions ◽  
Dispersion Relations ◽  
Near Surface ◽  
Wave Splitting ◽  
Proper Account ◽  
Acoustic Dispersion ◽  
Field Inclination

Local helioseismology seeks to probe the near surface regions of the Sun, and in particular of active regions. These are distinguished by their strong magnetic fields, yet current local techniques do not take proper account of this. Here, we first derive appropriate gravito-magneto-acoustic dispersion relations, and then use these to examine how acoustic rays entering regions of strong field split into fast and slow components, and the subsequent fates of each. Specifically, two types of transmission point, where wave energy can transfer from the fast to slow branch (or vice versa) are identified; one close to the equipartition level where the sound and Alfvén speeds coincide, and one higher up near the acoustic cutoff turning point. This second type only exists for rays of low frequency or low l though. In accord with recent studies of fast-to-slow mode conversion from the perspective of p-modes, magnetic field inclination is found to have significant consequences for wave splitting.

scholarly journals Kinetic and Activation Characteristics of Structure Rearrangement Processes in Ethoxylated Isononylphenol Derivates

2020 ◽  
pp. 17-30
Author(s):  
S. V. Mysik
Keyword(s):  
Activation Parameters ◽  
Liquid Structure ◽  
Relaxation Theory ◽  
Structure Rearrangement ◽  
Collective Processes ◽  
Region Data ◽  
Calculation Results ◽  
Acoustic Spectra ◽  
Rearrangement Processes ◽  
Acoustic Dispersion

The paper presents the calculation results of the kinetic and activation characteristics of fast and ultrafast structure rearrangement processes in liquid hydroxyethylated derivates of isononylphenol (ОНФn). Parameters were calculated using the relaxation theory of acoustic spectroscopy of liquids based on the analysis of the acoustic spectra of speed and sound absorption of the hydroxyethylated derivates of isononylphenol. The paper shows that two simple regions of acoustic dispersion can describe the acoustic spectra in the frequency range from 12 MHz to 2 GHz and the temperature range from 253 K to 323 K. The dispersion region data in the hydroxyethylated derivates of isononylphenol correspond to the interconnected reactions of OH ... O bonding and breaking in chain associates and spatially branched network structures. It is noted that the change in the spatial structure of liquid hydroxyethylated derivates of isononylphenol can be considered as a set of the large number of independent (for non-collective processes) and interconnected (for collective processes) local rearrangements of the liquid structure as a result of the thermal motion of molecules. The proposed molecular mechanism of acoustic relaxation and the kinetic model of fast and ultrafast structure rearrangement processes of the hydroxyethylated derivates of isononylphenol made it possible to explain the main experimental results and to calculate the kinetic and activation characteristics of the structure rearrangement processes of the hydroxyethylated derivates of isononylphenol. This model and the kinetic and activation parameters of the hydroxyethylated derivates of isononylphenol can find application in development of various technologies for using nonionic surfactants.

Acoustic dispersion and the ultrasound absorption of freon vapor

1972 ◽  
Vol 9 (3) ◽  
pp. 331-332
Author(s):  
S. G. Komarov ◽  
A. N. Solov'ev ◽  
E. P. Sheludyakov
Keyword(s):  
Ultrasound Absorption ◽  
Acoustic Dispersion

Acoustic dispersion in glow discharge plasma: A phenomenological analysis

2002 ◽  
Vol 14 (1) ◽  
pp. 427-429 ◽  
Author(s):  
V. S. Soukhomlinov ◽  
V. Y. Kolosov ◽  
V. A. Sheverev ◽  
M. V. Ötügen
Keyword(s):  
Glow Discharge ◽  
Discharge Plasma ◽  
Phenomenological Analysis ◽  
Glow Discharge Plasma ◽  
Acoustic Dispersion

Acoustic dispersion in a ball-shaped surface acoustic wave device

2007 ◽  
Vol 90 (21) ◽  
pp. 214105 ◽  
Author(s):  
Kazushi Yamanaka ◽  
Kanwar Jit Singh ◽  
Naoya Iwata ◽  
Takuji Abe ◽  
Shingo Akao ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Shaped Surface ◽  
Surface Acoustic Wave Device ◽  
Acoustic Wave Device ◽  
Wave Device ◽  
Acoustic Dispersion

The measurement of acoustic dispersion in loosely consolidated, saturated sediments using a water‐filled impedance tube

2002 ◽  
Vol 112 (5) ◽  
pp. 2363-2363
Author(s):  
Preston S. Wilson ◽  
Eun‐Joo Park ◽  
Ronald A. Roy ◽  
William M. Carey
Keyword(s):  
Impedance Tube ◽  
Acoustic Dispersion

scholarly journals Acoustic dispersion in a two-dimensional dipole system

2008 ◽  
Vol 78 (4) ◽  
Author(s):  
Kenneth I. Golden ◽  
Gabor J. Kalman ◽  
Zoltan Donko ◽  
Peter Hartmann
Keyword(s):  
Two Dimensional ◽  
Dipole System ◽  
Acoustic Dispersion
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