Results 251 to 260 of about 8,674 (299)

Backscatter coefficient estimation using array transducers

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1994
This paper describes an extension of our broadband method for estimating backscatter coefficients from random media to include data from array transducers. Four different transducer designs have now been considered: oneand two-dimensional linear arrays, annular arrays, and single-element focused pistons commonly used in mechanical sector scanners.
M F, Insana, T J, Hall, L T, Cook
openaire   +2 more sources

Backscatter coefficient imaging using a clinical scanner

Medical Physics, 1992
A clinical ultrasound scanner has been integrated with a digital data acquisition system to record echo signals for off‐line processing of quantitative acoustic backscatter images. The method used to determine backscatter coefficients accounts for experimental factors related to the beam directivity function, the transmitting and receiving electronics,
E J, Boote, J A, Zagzebski, E L, Madsen
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Polarization and atmospheric backscatter coefficient measurements

Applied Optics, 1989
Recently, it was pointed out that polarization effects must be considered in hard target calibration of lidars. A vector theory of radiometry is developed, and it is demonstrated for a real nonideal target that the reflectance is a matrix quantity and not a scalar quantity, and all its components must be measured.
openaire   +2 more sources

Clinical assessment of the backscatter coefficient in osteoporosis

1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118), 2002
Current commercial ultrasound "bone densitometers" process only the through-transmitted signals while failing to extract additional information contained in the scattered signals. This work was conducted to investigate the clinical interest of a backscatter ultrasound technique for bone characterization in 24 healthy premenopausal (group N), 24 ...
P. Laugier, P. Giat, C. Chappard, C. Roux, G. Berger   +4 more
openaire   +1 more source

Analytical Expressions for the Electron Backscattering Coefficient

Physica Status Solidi (a), 1989
Several analytical expressions for the electron backscattering coefficient for massive homogeneous samples are compared with experimental data, directing special attention to the dependence of this quantity on the electron acceleration energy. It is shown that this dependence generally cannot be neglected.
H. -J. August, J. Wernisch
openaire   +1 more source

An energy-dependent electron backscattering coefficient

Journal of Applied Physics, 1987
An energy-dependent electron backscattering coefficient is derived based on the continuous slowing down approximation and the Bethe stopping power. Backscattering coefficients are given for 10–50-keV electrons incident on bulk and thin-film aluminum, silver, and gold targets.
W. Williamson, A. J. Antolak, R. J. Meredith   +2 more
openaire   +1 more source

Backscattering of low energy electrons from carbon films deposited on aluminum: A Monte Carlo simulation

Journal of Applied Physics, 2004
The low energy backscattering coefficient for the special case of film of carbon deposited on aluminum is investigated. The backscattering coefficient as a function of the primary energy shows an interesting property, i.e.
Maurizio Dapor, Dapor Maurizio
exaly   +2 more sources

Backscattering coefficient of a perturbed sinusoidal surface

IEEE Transactions on Antennas and Propagation, 1984
A coherent model for scattering from a randomly perturbed periodic surface is developed using the Kirchhoff approximation. It is intended to model wave scattering from ground surfaces with row directions. Results are illustrated and compared with an incoherent scatter model and measured backscattering angular curves from ploughed fields.
null Hyo Eom, A. Fung
openaire   +1 more source

The reflection coefficient in stimulated parmetric backscattering

Journal of Applied Physics, 1977
The step-function approximation of the anomalous reflection coefficient in laser-induced parametric backscattering currently used in the theory of nonlinear laser plasma interactions is improved using a simple exponential derived from elliptic functions. The validity of the single-reflection analysis is reaffirmed.
Chung Yu, Hsiung Hsu
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Spectral backscattering coefficient in coastal waters

International Journal of Remote Sensing, 2005
Based on 186 field observations in the Oslo Fjord of irradiance and radiance and 105 laboratory measurements of beam attenuation, this analysis demonstrates that the ratio between the backscattering coefficient b pb and the scattering coefficient b p of the particles is wavelength dependent and not a constant value.
E. Aas, J. Høkedal, K. Sørensen
openaire   +1 more source