Results 231 to 240 of about 35,755 (265)

Group velocity, phase velocity, and dispersion in human calcaneusin vivo

The Journal of the Acoustical Society of America, 2007
Commercial bone sonometers measure broadband ultrasonic attenuation and/or speed of sound (SOS) in order to assess bone status. Phase velocity, which is usually measured in frequency domain, is a fundamental material property of bone that is related to SOS, which is usually measured in time domain.
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Phonon dispersion sheets and group velocities in GaAs

Journal of Physics: Condensed Matter, 1990
Phonon frequencies on two dispersion sheets for TA modes have been determined by inelastic neutron scattering on the (001) and the (011) planes at 12 K. Phonon group velocities for these phonons have been derived. The results are used to calculate heat transport properties.
B Dorner, D Strauch
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Group-velocity dispersion in an all-pass Bragg filter

Optics Letters, 1994
On the basis of previously performed theoretical analysis it is shown that a slanted volume grating acts as an all-pass filter with nonlinear dispersion when the diffracted wave is evanescent. An analytical expression for the grating transfer function applicable over a wide angular range of mutual orientation of the initial wave and grating vectors is ...
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Energy transport in dispersive media and superluminal group velocities

Physics Letters A, 1997
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Supercontinuum in the anomalous group-velocity dispersion region

Journal of the Optical Society of America B, 1992
We compute numerically the time-domain characteristics and the spectral distribution of an intense femtosecond pulse with its center frequency in the anomalous group-velocity dispersion region, that is, propagating in a one-spatial-dimension Kerr medium (optical fiber).
Barry Gross, Jamal T. Manassah
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Huge group-velocity dispersion in a photonic crystal

SPIE Proceedings, 2005
We investigated the group-velocity dispersion of a one dimensional uniform photonic crystal by the optical transmission method. For application in optical communications, the wavelength should be near one of the two edges of a photonic bandgap. Four kinds of dispersion-compensation may be obtained with a photonic crystal.
Zhengbiao Ouyang, Yanyan Cai, Qingsheng Meng, Yali Lu, Yiling Sun, Dengguo Zhang, Shuangchen Ruan, Jingzhen Li   +7 more
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Causality and acoustic group velocity in dispersive media

The Journal of the Acoustical Society of America, 2005
This talk examines two specific issues related to causality and the group velocity of acoustic pulses in dispersive media. First, the causal prediction of group velocity from attenuation with finite-bandwidth Kramers-Kronig (K-K) relations is discussed.
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Group velocity and nonlinear dispersive wave propagation

Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, 1973
Abstract By the use of a Hamiltonian formulation, a basic group velocity is defined as the derivative of frequency with respect to wavenumber keeping action density constant, and is shown to represent an incremental action velocity in the general nonlinear case.
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Weakly nonlinear dispersive waves: group velocity

Journal of Plasma Physics, 1982
For slowly varying wave trains in a linear system, it is known that a quantity proportional to the square of the amplitude propagates with the group velocity. It is shown here, by considering a specific problem of longitudinal waves in a hot electron-plasma and using an asymptotic analysis, that this result continues to be valid even when weak ...
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Retrieving S-wave velocity from surface wave multimode dispersion curves with DispINet

Journal of Applied Geophysics, 2021
Lei Fu, Lei Pan, Sheng Dong
exaly