An analysis of wave front motion in weakly coupled doped semiconductor superlattices is presented. If a dimensionless doping is sufficiently large, the superlattice behaves as a discrete system presenting front propagation failure and the wave fronts can be described near the threshold currents J(i) (i=1,2) at which they depin and move. The wave front velocity scales with current as |J-J(i)|(1/...

[1] This study compares the atmospheric total precipitable water (PWV) obtained by Atmospheric Infrared Sounder (AIRS) with radiosondes and the European Centre for Medium-range Weather Forecasts (ECMWF) operational analysis products during December 2003 and January 2004. We find that PWV from AIRS Level 3 (daily gridded) data is about 9% drier while ECMWF is 14% moister than sondes at the two g...

Stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. In all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. The dependency of per...

summary based on the results of the analysis of site effects, mostly those with shear wave velocity and the fundamental period chosen as the basis for classification. in revision of earthquake resistant design regulations for buildings, classification of lands should be subject to the field conditions, geological, geotechnical, geophysical, and laboratory tests.in this context, the average shea...

Love waves are generally less employed than Rayleigh waves in near-surface shear-wave (S-wave) investigations because acquiring S-wave data is not as easy as acquiring P-wave data. The dispersion of Love waves, however, is independent of Poisson’s ratio. This character can be the valuable basis to improve the S-wave velocity imaging. The sensitivity of earth properties to the dispersion curve o...

A 2D finite element model for the solution of wave equations is developed. The fluid is considered as incompressible and irrotational. This is a difficult mathematical problem to solve numerically as well as analytically because the condition of the dynamic boundary (Bernoulli’s equation) on the free surface is not fixed and varies with time. The finite element technique is applied to solve non...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...

[1] We apply seismic interferometry to strong-motion records to detect the near-surface (i.e., an upper few hundred meters deep) change in anisotropy caused by the MW 9.0 Tohoku-Oki earthquake on 11 March 2011. We show that the earthquake increased the difference between fast and slow shear-wave velocities arising from shear-wave splitting in most parts of northeastern Japan, but it did not sig...

optimization of reservoir parameters is an important issue in petroleum exploration and production. the ant colony optimization(aco) is a recent approach to solve discrete and continuous optimization problems. in this paper, the ant colony optimization is usedas an intelligent tool to estimate reservoir rock properties. the methodology is illustrated by using a case study on shear wave velocity...