Waveguide dispersion curves identification at low-frequency using two actuators and phase perturbations

2019 ◽  
Vol 146 (4) ◽  
pp. 2443-2451 ◽  
Author(s):  
Yoav Vered ◽  
Ran Gabai ◽  
Izhak Bucher
Keyword(s):  
Low Frequency ◽  
Dispersion Curves ◽  
Waveguide Dispersion

scholarly journals Краевые колебания нанолент графана

2018 ◽  
Vol 60 (5) ◽  
pp. 1029
Author(s):  
А.В. Савин
Keyword(s):  
Force Field ◽  
Frequency Spectrum ◽  
High Frequency ◽  
Low Frequency ◽  
Dispersion Curves ◽  
Linear Vibrations ◽  
The Mean

AbstractUsing the COMPASS force field, natural linear vibrations of graphane (graphene hydrogenated on both sides) nanoribbons are simulated. The frequency spectrum of a graphane sheet consists of three continuous intervals (low-frequency, mid-frequency, and narrow high-frequency) and two gaps between them. The construction of dispersion curves for nanoribbons with a zigzag and chair structure of the edges show that the frequencies of edge vibrations (edge phonons) can be present in the gaps of the frequency spectrum. In the first type of nanoribbons, two dispersion curves are in the low-frequency gap of the spectrum and four dispersion curves in the second gap. These curves correspond to phonons moving only along the nanoribbon edges (the mean depth of their penetration toward the nanoribbon center does not exceed 0.15 nm).

DETERMINATION OF SPATIAL ATTENUATION OF NORMAL WAVES IN A SHALLOW SEA

2019 ◽  
pp. 37-42
Author(s):  
U.V. Makhnev ◽  
O.I. Piskunova ◽  
A.T. Trofimov
Keyword(s):  
Attenuation Coefficient ◽  
Low Frequency ◽  
Sound Field ◽  
Pulse Method ◽  
Dispersion Curves ◽  
Frequency Region ◽  
Shallow Sea ◽  
Normal Waves ◽  
Spatial Attenuation

This article discusses the possibility of estimating the spatial attenuation coefficient in the low-frequency region (<100 Hz) for individual normal waves and for the integral sound field created by a moving ship. A pulse method was used to resolve and obtain dispersion curves of normal waves. Estimates of the attenuation coefficient were obtained, and the possibility of determining the attenuation coefficient from noise signals of navigation was investigated.

Comparison of Two Methods in Solving Rayleigh Dispersion Curves

2011 ◽  
Vol 66-68 ◽  
pp. 1848-1853
Author(s):  
Bo Qin ◽  
Yan Mei Cao ◽  
He Xia
Keyword(s):  
Thin Layer ◽  
Frequency Domain ◽  
High Frequency ◽  
Low Frequency ◽  
Dispersion Curves ◽  
Layered Soil ◽  
Layer Method ◽  
Soil Model ◽  
Thin Layer Method

The Rayleigh dispersion curves of multilayered soil are calculated by means of thin-layer method and rapid scalar method, respectively, in which two-layered and three-layered soil model are adopted. In addition, the disperse properties of multilayered soil are analyzed, and it is found that thin layer method is superior to rapid scalar method in low frequency domain, while in the high frequency domain it has little difference between each other.

Zur Auswertung dielektrischer Relaxations­ messungen / Transformation method for evaluation of dielectric measurements

1977 ◽  
Vol 32 (9) ◽  
pp. 1059-1060 ◽  
Author(s):  
G. Schufmann ◽  
W. Gunßer
Keyword(s):  
Complex Permittivity ◽  
Low Frequency ◽  
Good Method ◽  
Transformation Method ◽  
Dispersion Curves ◽  
Dielectric Measurements ◽  
Complex Polarizability

Transformation of the complex permittivity ε* in a complex polarizability α' proved to be a good method for observing low frequency dispersions in solids. The effect of transformation is due to a shift in the maxima of the dispersion curves to higher frequencies.

THE HYDROGEN ION EFFECT IN WHISTLER DISPERSION

1960 ◽  
Vol 38 (12) ◽  
pp. 1642-1653 ◽  
Author(s):  
R. E. Barrington ◽  
T. Nishizaki
Keyword(s):  
Simple Formula ◽  
Low Frequency ◽  
Dispersion Curves ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Positive Ions ◽  
Filtering Technique ◽  
Low Altitude

Four low-altitude whistlers have been carefully analyzed by a specially developed filtering technique. In each case the low-frequency portions of the resulting dispersion curves show similar departures from the simple [Formula: see text] law developed by Eckersley. The departures are found to be of the form and magnitude predicted by Storey on the assumption that the propagation is partly supported by the light hydrogen ions of the exosphere. If it is assumed that the observed deviations are due only to hydrogen ions, and that above some transitional level the positive ions are mostly hydrogen, an estimate of 1000 km for the height of the transitional level is obtained.

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