Zobrazeno 1 - 10
of 37
pro vyhledávání: '"Robert F. Gragg"'
Publikováno v:
International Journal of Quantum Chemistry. 16:695-704
We arrive at transition probabilities for a laserlike system by neglecting wave properties of matter and radiation, and treating the problem, in an analogy to chemical systems, entirely in a number representation. Thus, for example, stimulated emissi
Publikováno v:
IEEE Journal of Oceanic Engineering. 32:897-914
Diverse aspects of stochastic processes, time-series analysis, fractal geometry, and manufacturing technology are brought together to provide a unified theoretical framework for the mathematical characterization and physical fabrication of scale-mode
Autor:
Robert F. Gragg
Publikováno v:
The Journal of the Acoustical Society of America. 114:1387-1394
Analytic methods are used to formulate the impact of a random dynamic sea surface on the space-frequency characteristics of bistatic reverberation. A narrow-band point source is positioned beneath the time-dependent surface of a range-independent oce
Publikováno v:
The Journal of the Acoustical Society of America. 110:2878-2901
In this article acoustic scattering by a random rough interface that separates a fluid incident medium from an underlying uniform scattering medium, either fluid or elastic solid, in cases for which the Bragg scale lies within the power-law tail of t
Autor:
Robert F. Gragg, David M. Drumheller
Publikováno v:
The Journal of the Acoustical Society of America. 110:2270-2275
An algorithm is presented for the numerical evaluation of a fundamental but intractable integral that occurs in the physical theory of scattering from random rough surfaces. It is based on a rational-function approximation to an integrand factor, aug
Autor:
Robert F. Gragg
Publikováno v:
Wave Motion. 27:95-115
A series of energy-conserving generalized rotations is applied to the Helmholtz equation for a weakly nonuniform one-dimensional medium. These transformations decouple the wave field, to arbitrary order in the strength of the nonuniformity, into coun
Autor:
Robert F. Gragg, Daniel Wurmser
Publikováno v:
The Journal of the Acoustical Society of America. 98:473-483
An analytic expression is found for the scattered spectrum that is produced when a model dynamic bubble plume is ensonified by a continuous wave (cw) signal. The plume is of the ‘‘intermediate’’ type—with an interior sound speed well below
Autor:
Daniel Wurmser, Robert F. Gragg
Publikováno v:
The Journal of the Acoustical Society of America. 94:319-329
The acoustic field scattered from a bubble plume near the ocean surface is evaluated. It is assumed that the total field obeys the wave equation below a flat pressure‐release air/sea interface, and that the interior of the plume can be represented
Autor:
Bruce H. Pasewark, Robert F. Gragg
Publikováno v:
The Journal of the Acoustical Society of America. 89:682-690
High‐resolution algorithms are potentially able to outperform conventional linear methods at the task of beamforming, i.e., spatial‐spectrum estimation, and in controlled experiments or simple computer simulations they often do prove superior. In
Publikováno v:
The Journal of the Acoustical Society of America. 122(5)
An underwater acoustic experiment with a two-dimensional rough interface, milled from a slab of PVC, was performed at a tank facility. The purpose was to verify the predictions of numerical models of acoustic rough surface scattering, using a manufac