scholarly journals Reduced models in the medium-frequency range for general external structural-acoustic systems

1998 ◽  
Vol 103 (6) ◽  
pp. 3393-3406 ◽  
Author(s):  
Christian Soize
Keyword(s):  
Frequency Range ◽  
Medium Frequency ◽  
Reduced Models ◽  
Medium Frequency Range

Reduced Models for Computational Structural Acoustics in the Medium-Frequency Range

1999 ◽  
Author(s):  
Christian Soize
Keyword(s):  
Frequency Band ◽  
Three Dimensional ◽  
Energy Operator ◽  
Structural Acoustics ◽  
Frequency Range ◽  
Medium Frequency ◽  
Reduced Models ◽  
Acoustic Cavity ◽  
Frequency Behavior ◽  
Medium Frequency Range

Abstract This paper deals with a method in computational structural acoustics adapted for constructing reduced models in the medium-frequency range to a general three-dimensional dissipative structure consisting of an anisotropic, inhomogeneous, viscoelastic bounded medium coupled with an internal acoustic cavity. The reduced models are obtained using the Ritz-Galerkin method for which the projection subspace corresponds to the dominant eigensubspace of the energy operator of the structure in the medium-frequency band of analysis. A basic example is presented to validate the method, for which the structure and the internal acoustic cavity have a medium-frequency behavior in the frequency band of analysis.

Topographic Analysis of Steady-State Visual Evoked Potentials (SVEPs) in The Medium Frequency Range in Migraine With and Without Aura

Cephalalgia ◽  
1992 ◽  
Vol 12 (4) ◽  
pp. 244-249 ◽  
Author(s):  
Franco M Puca ◽  
Marina de Tommaso ◽  
Maria A Savarese ◽  
Sergio Genco ◽  
Addolorata Prudenzano
Keyword(s):  
Steady State ◽  
Frequency Range ◽  
Medium Frequency ◽  
Topographic Analysis ◽  
Absolute Power ◽  
Interhemispheric Coherence ◽  
The Mean ◽  
Student’S T ◽  
Medium Frequency Range ◽  
Student’S T Test

Topographic analysis of SVEPs in the medium frequencies range was performed in 30 migraineurs without aura, 20 migraineurs with aura and in 20 control subjects. The mean absolute power values of the fundamental component F1, the subharmonic F1/2 and the first harmonic F2, corrected by logarithmic transformation, were computed in each group and then compared using Student's t-test. The interhemispheric coherence of the F1 component was also evaluated. The 18, 21 and 27 Hz F1 components were increased in both migraineurs with and without aura, particularly in the temporo-parietal regions. The 24 Hz F1 component was augmented only in migraineurs without aura in the parieto-occipital regions in comparison with migraineurs with aura and controls. Migraine with aura patients had a reduced interhemispheric coherence mostly of 12 Hz and 15 Hz F1 components in frontal and temporo-parietal regions. Results of the study confirm abnormalities of SVEPs in migraineurs with and without aura. These consist of widespread increases of F1 components in the medium frequency range over the temporo-parietal regions.

Measurements of the Surface Elasticity in Medium Frequency Range Using the Oscillating Bubble Method

1998 ◽  
Vol 208 (1) ◽  
pp. 34-48 ◽  
Author(s):  
Klaus-Dieter Wantke ◽  
Horst Fruhner ◽  
Jiping Fang ◽  
Klaus Lunkenheimer
Keyword(s):  
Surface Elasticity ◽  
Frequency Range ◽  
Medium Frequency ◽  
Medium Frequency Range
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