scholarly journals High frequency intravascular photoacoustic (IVPA) imaging for differentiating arterial wall layered structures

2012 ◽  
Author(s):  
Xiang Li ◽  
Wei Wei ◽  
Qifa Zhou ◽  
K. Kirk Shung ◽  
Zhongping Chen
Keyword(s):  
High Frequency ◽  
Arterial Wall ◽  
Layered Structures

Fundamental properties of surface waves in lossless stratified structures

2010 ◽  
Vol 466 (2120) ◽  
pp. 2447-2469 ◽  
Author(s):  
Guido Valerio ◽  
David R. Jackson ◽  
Alessandro Galli
Keyword(s):  
Surface Waves ◽  
Dispersion Equation ◽  
High Frequency ◽  
Low Frequency ◽  
Layered Structures ◽  
Graphical Solution ◽  
Fundamental Properties ◽  
The Past ◽  
Permittivity And Permeability ◽  
Constitutive Parameters

This paper is focused on dispersive properties of lossless planar layered structures with media having positive constitutive parameters (permittivity and permeability), possibly uniaxially anisotropic. Some of these properties have been derived in the past with reference to specific simple layered structures, and are here established with more general proofs, valid for arbitrary layered structures with positive parameters. As a first step, a simple application of the Smith chart to the relevant dispersion equation is used to prove that evanescent (or plasmonic-type) waves cannot be supported by layers with positive parameters. The main part of the paper is then focused on a generalization of a common graphical solution of the dispersion equation, in order to derive some general properties about the behaviour of the wavenumbers of surface waves as a function of frequency. The wavenumbers normalized with respect to frequency are shown to be always increasing with frequency, and at high frequency they tend to the highest refractive index in the layers. Moreover, two surface waves with the same polarization cannot have the same wavenumber at a given frequency. The low-frequency behaviours are also briefly addressed. The results are derived by means of a suitable application of Foster’s theorem.

Validation of in vivo noninvasive high-frequency ultrasonography of the arterial wall layers

2001 ◽  
Vol 27 (6) ◽  
pp. 751-756 ◽  
Author(s):  
Kenny A Rodriguez-Macias ◽  
Tord Naessen ◽  
David Bergqvist
Keyword(s):  
High Frequency ◽  
Arterial Wall ◽  
High Frequency Ultrasonography

DEFECT DETECTION IN MULTI-LAYERED STRUCTURES USING HIGH FREQUENCY GUIDED WAVES

2011 ◽  
Author(s):  
B. Masserey ◽  
E. Kostson ◽  
P. Fromme ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Defect Detection ◽  
High Frequency ◽  
Guided Waves ◽  
Layered Structures

scholarly journals Investigating the Effect of Dimension Parameters on Sound Transmission Losses in Nomex Honeycomb Sandwich

2020 ◽  
Vol 10 (9) ◽  
pp. 3109 ◽  
Author(s):  
Da Wang ◽  
Suchao Xie ◽  
Zhejun Feng ◽  
Xiang Liu ◽  
Yingli Li
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Layered Structures ◽  
Test Method ◽  
Core Material ◽  
Impedance Tube ◽  
Tube Test ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb

In this study, an impedance tube test was performed to explore the influence of various dimension parameters of Nomex honeycomb sandwich core material on sound transmission loss (STL). The parameters investigated included the size of the honeycomb cells and thickness of the face sheets and honeycomb cores, and the effects of single- and double-layered sandwich structures were also explored. The boundary element and finite element methods were used to simulate test results. The results show that the size of the honeycomb cells has an insignificant effect on STL. Increasing the thickness of face sheets can move the STL valley point of the material at high frequency (around 5 kHz) in the low-frequency direction and increase the STL in parts of the high frequency band. Increasing the thickness of the honeycomb core can improve STL, on the whole, but the magnitude of the improvement effect becomes weakened after the thickness of the core reaches 30 mm. The STL of double-layered structures was found to be superior to that of the single-layered structures. The simulations reveal that the trends in the STL curves of the honeycomb sandwich panels are influenced by the structural mode of the panels, and are related to the resonance of the materials. The results and relevant conclusions obtained through the above research verify that the law of influence of the structure dimension parameters on the STL measured by the impedance tube is similar to that of the large panel. This can provide a reference for the application of the impedance tube test method in structural noise reduction design.

High-frequency signal processing using magnetic layered structures

2009 ◽  
Vol 321 (14) ◽  
pp. 2048-2054 ◽  
Author(s):  
R.E. Camley ◽  
Z. Celinski ◽  
T. Fal ◽  
A.V. Glushchenko ◽  
A.J. Hutchison ◽  
...  
Keyword(s):  
Signal Processing ◽  
High Frequency ◽  
Layered Structures ◽  
Frequency Signal ◽  
High Frequency Signal
Sign in / Sign up

Export Citation Format

Share Document