Results 261 to 270 of about 104,884 (306)

Relative Spectral Attenuation Coefficients of Water

Applied Optics, 1967
The relative variation of attenuation coefficient with wavelength has been studied in the laboratory for distilled water and seawater. The study was for the purpose of locating any very fine structure in the attenuation vs wavelength curve. The spectral region from 3750 A to 6850 A was examined with 0.2 A resolution; water paths were 9.7 m and 19.5 m ...
L F, Drummeter, G L, Knestrick
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Estimation of the Slope of the Acoustic Attenuation Coefficient

Ultrasonic Imaging, 1984
In this paper, a theoretical framework is developed which removes the Gaussian assumption commonly used in ultrasonic attenuation estimation based on mean frequency shift. The theory is developed for general non-Gaussian spectra and for media whose attenuation coefficient is nonlinear with frequency.
S, Shaffer, D W, Pettibone, J F, Havlice, M, Nassi   +3 more
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Mass-attenuation coefficients of beta particles

International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes, 1990
Abstract A method to obtain mass-attenuation coefficients of β particles is described. This method is based upon the simulation of β emission by means of the β energy spectrum. The range of the β particle is chosen as random incidence by means of range distribution of monoenergetic electrons which have the same energy as the β particle.
CENGIZ, AHMET, OZMUTLU, C
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An accurate parametrisation of the X-ray attenuation coefficient

Physics in Medicine & Biology, 1980
A parametrisation starting from the fundamental theory of photon-electron interactions has been devised. In this note the authors report the expression obtained and the accuracy achieved for elements common in tissue and contrast media.
D J, Hawkes, D F, Jackson
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Attenuation and reflection coefficient nomogram

Ultrasonics, 1974
Abstract A nomogram is described for the determination of the sound pressure reflection coefficient R and the round-trip loss 2 α L when using the pulse-echo buffer rod technique.
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An Anisotropic Modelling for the Determination of Regional Attenuation Coefficients

Natural Hazards, 1998
The anisotropic attenuation of macroseismic intensity for a seismogenetic zone is dealt with using a new modelling of intensity distribution. The analysis, carried out starting from the intensity maps of the earthquakes of different seismogenetic zones of Central and Southern Italy, allows the determination of the attenuation coefficients for each ...
TERAMO, Antonio, TERMINI, Domenica, STILLITANI E., BOTTARI, Antonio   +3 more
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MEASUREMENT OF ATTENUATION COEFFICIENTS IN NATURAL WATER COLUMNS

Environmental Toxicology and Chemistry, 1987
Abstract Light scattering and light absorption by particulates and humic substances in natural waters can significantly affect the photoreaction rates of chemicals in aquatic systems. These scattering and absorption processes are quantitatively described by the use of an empirical parameter, the diffuse attenuation coefficient, K.
John S. Winterle, Doris Tse, William R. Mabey   +2 more
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Linear attenuation coefficients for compensator based imrt

Australasian Physics & Engineering Sciences in Medicine, 2007
With rapid technological improvements in computer driven 3-D radiotherapy treatment planning systems (RTPS) the use of compensating filters for intensity modulated radiation therapy (IMRT) will dramatically increase the ease of treatment. The procedure for commissioning .decimal (Sanford, Florida) compensators involved the measurement of the effective ...
T, Bartrum, M, Bailey, V, Nelson, M, Grace   +3 more
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Absolute values of attenuation coefficients in computed tomography

Physics in Medicine & Biology, 1979
A reconstruction is made of the water box of a water box scanner; identical measurements result at each sampling position (ignoring quantum noise); zero values emerge after convolution and their back-projection sum is also zero. The water box is then filled with any other uniform medium and the procedure repeated.
null C H Marshall, null J C Gore, null P S Tofts   +2 more
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Method for Estimating the Diffuse Attenuation Coefficient from the Beam Attenuation Coefficient in the Waters of the Black Sea

Fundamental and Applied Hydrophysics
The vertical attenuation coefficient of downward irradiance is one of the hydro-optical characteristics that determine the parameters of the light field in the sea. Information from the vertical attenuation coefficient of downward irradiance (or the diffuse attenuation coefficient) is necessary when determining an important biological and ecological ...
V. I. Mankovsky, E. V. Mankovskaya
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