Determinations of shear wave speeds of sound and attenuation coefficients are reported for soft tissues, a silicone rubber reference material, and a gel used in manufacturing ultrasonically tissue-mimicking materials. Fresh bovine tissues were investigated, including calfskin, liver, cardiac muscle, and striated muscle. Because of the very large shear wave attenuation coefficients, reasonably a...

The dispersion equation is analyzed for waves in a strongly magnetized, electron-positron plasma in which counterstreaming electrons are cold in their respective rest frames. For propagation parallel to the magnetic field the dispersion equation factorizes into equations for two longitudinal modes and four transverse modes. Instabilities occur in both longitudinal and transverse modes, with the...

In this study, the effect of small-scale of both nanostructure and nano-fluid flowing through it on the natural frequency and longitudinal wave propagation are investigated. Here, the stationary and axially moving single-walled carbon nanotube conveying fluid are studied. The boundary conditions for the stationary nanotube is considering clamped-clamped and pined-pined and for the axially movin...

Wegeneralize the theory of Cooper-pairing by spin excitations in themetallic antiferromagnetic state to include situationswith electron and/or hole pockets.We show that Cooper-pairing arises from transverse spinwaves and fromgapped longitudinal spinfluctuations of comparable strength. However, each of these interactions, projected on a particular symmetry of the superconducting gap, acts primar...

Background: The theory of microstretch elastic bodies was first developed by Eringen (1971, 1990, 1999, 2004). This theory was developed by extending the theory of micropolar elastcity. Each material point in this theory has three deformable directors. Methods: The governing equations of a transversely isotropic microstretch material are specialized in x-z plane. Plane wave solutions of these g...

In this paper we present the first detailed study of the excitation of high phase velocity plasma waves by colinear optical mixing. The plasma wave frequency and wavenumber, hence the phase velocity, are directly measured using Thomson scattering. The amplitude of the plasma wave and therefore the longitudinal electric field is inferred from the magnitude of the Thomson scattered light. For a m...

When an ultrasonic wave is incident on a water/solid interface generally three waves are excited in the solid: one longitudinal and two shear. The complex amplitudes of the transmitted waves depend on the material properties and the angle of incidence. At incident angles higher than the first critical angle an evanescent longitudinal wave is excited near the surface. To satisfy the boundary con...

We study the longitudinal motion of beam particles under the action of a single resonator wave induced by the beam itself. Based on the method of multiple scales we derive a system of coupled amplitude equations for the slowly varying part of the longitudinal distribution function and for the resonator wave envelope, corresponding to an arbitrary wave number. The equation governing the slow evo...

This paper describes the methods of sampling design and data collection of Wave 1, 2 and 3 of the International Tobacco Control (ITC) China Survey, with major focus on longitudinal features of the study. Key measures of quality of the survey data, such as retention rates and final sample sizes, are presented. Sample replenishment procedures are outlined, including the addition of a new city, Ku...

A high-order continuum model is developed to study wave propagation in nanowires. By using the model, heterogeneous nanostructure effects can be captured especially for high wave frequency cases. Surface stress effects are also included by using the incremental deformation approach. The governing equations of motion in the nanowire are derived including both the strain-independent and strain-de...