Results 251 to 260 of about 5,564 (299)

Separation of Channel Backscattering Coefficients in Nanoscale MOSFETs

IEEE Transactions on Electron Devices, 2004
Channel backscattering coefficients in the k/sub B/T layer (near the source) of 1.65-nm-thick gate oxide, 68-nm gate length bulk n-channel MOSFETs are systematically separated into two distinct components: the quasithermal-equilibrium mean-free-path for backscattering and the width of the k/sub B/T layer.
M -J Chen, Ming-Jer Chen
exaly   +2 more sources

Improved Resolution Backscatter Coefficient Imaging

Ultrasonic Imaging, 1991
This paper reports the extension of a method for imaging acoustic backscatter coefficients that allows for greater spatial resolution in the resulting images. This is done by using a broad-band excitation pulse and short-duration time gates in the analysis.
E J, Boote, T J, Hall, E L, Madsen, J A, Zagzebski   +3 more
openaire   +3 more sources

Terrain backscattering coefficient generator

IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010), 2003
A generator for producing backscattering coefficient (/spl sigma//sup 0/) values for several terrain types under varying measurement conditions is developed. The types of terrain include soils and rocks, trees, grasses, shrubs, short vegetation, roads, urban areas, dry snow, and wet snow with measurements coming from the University of Michigan (Ulaby ...
R. Mediavllla, W. O'Connor, V. Pyati
openaire   +2 more sources

Instrument-Independent Acoustic Backscatter Coefficient Imaging

Ultrasonic Imaging, 1988
This paper presents an adaptation of a method for determining acoustic backscatter coefficients to produce quantitative ultrasound images. Backscattered echo signals are recorded from a region to be imaged and backscatter coefficients are determined and related to spatial position.
E J, Boote, J A, Zagzebski, E L, Madsen, T J, Hall   +3 more
openaire   +3 more sources

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
openaire   +2 more sources

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