A corrugated magnetic reflector is realized by adding a bias field to a static magnetic mirror. This permits real-time manipulation of a cold-atom cloud on time scales down to 100 ms. We show that rotation of the bias field generates a traveling corrugation of adjustable depth and velocity. Momentum is transferred from the traveling wave to the atoms, resulting in a displacement of the cloud th...

Abstract The example of vertical propagation acoustic plane waves in the atmosphere is used to establish that reflectionless occurs only continuously stratified media for which wave equations with variable pressure perturbation and vibrational velocity coefficients are reduced—via same transformation impedance profile, inversely proportional refractive index—to a comparison equation constant co...

recordings of ambient noise or microtremors are increasingly used to find valuable information on soil in one dimension at a given site. ambient vibrations, which are assumed to be mainly composed of surface waves, can be used to determine the surface wave dispersion curve in order to retrieve shear wave velocity profile. in this regard, microtremors are usually recorded simultaneously in an ar...

In this paper we setup a model based on complex medium (composite), which considers randomly distributed characteristics of medium. A finitedifference method (FDM) of estimating velocity for composite based on elastic-wave theory is used. The FDM wave equation using stress-particle velocity equations, and the scheme is second–order accurate in time and eight-order accurate in space, In order to...

GABRIELS, P., SNIEDER, . and NOLET, G. 1987, In Situ Measurement of Shear-Wave Velocity in Sediments with Higher-Mode Rayleigh Waves, 35,187-196. A seismic survey was carried out on a tidal flat in the SW-Netherlands in order to determine shear-wave velocities in sediments by means of higher-mode Rayleigh waves. The dispersion properties of these Rayleigh waves were measured in the 2-D amplitud...

We have developed a method for three-dimensional simultaneous velocity and density inversion using traveltimes of local earthquakes and gravity data. The purpose of this method is to constrain the velocity inversion and increase the spatial resolution of shallow velocity structures by introducing additional gravity data. The gravity data contributes to the Pand S-wave velocity models by imposin...

The propagation and radiation properties of dual composite right/left-handed (D-CRLH) transmission line metamaterials are presented, and validated experimentally with a 1D microstrip prototype. In its fast-wave regime, this structure operates as a leaky-wave antenna capable of backfire-to-endfire radiation scanning with beam squinting smaller than that of conventional CRLH (C-CRLH) antennas. It...

In the present paper, the Zelt algorithm has been extended for ray tracing through an anisotropic model. In anisotropic media, the direction of the propagated energy generally differs from that of the plane-wave propagation. This makes velocity values to be varied in different directions. Therefore, velocity modeling in such media is completely different from that in an isotropic media. The vel...

development of ultrasound technique has not been progressing for evaluating the internal quality of fruits as fast as that of processed foods. in this research for quality assessment of pear fruit (shah miveh variety) an ultrasonic measurement system was constructed to transmit and receive the ultrasonic waves. the apparatus included a pulser-receiver, a pair of 75 khz ultrasonic transducers wi...

Asymptotic expansions for small Strouhal number, valid for arbitrary subsonic Mach number, are derived for the solution of a simple problem of the interaction between an acoustic wave, a jet flow and a pipe, based on Munt's [ l ] exact formal solution. These expansions relate to the pressure and velocity fluctuations in the jet flow and in the far field, and to the reflection coefficient, end-i...