Zobrazeno 1 - 10
of 40
pro vyhledávání: '"D.N. MacLennan"'
Publikováno v:
ICES Journal of Marine Science. 61:201-210
During acoustic surveys for biomass estimation, fish aggregations near the seabed may not be correctly measured due to false detection of the bottom echo. The extent of this problem depends on the spatial and density features of the near-seabed aggre
Autor:
J.R. Dunn, D.N. MacLennan
Publikováno v:
Journal of Sound and Vibration. 97:321-331
Tungsten carbide spheres have been used as reference targets to calibrate echosounders. The target strength depends upon the longitudinal and transverse stress wave speeds, c1 and c2, in the sphere. These may be estimated from the resonance frequenci
Autor:
D.N. MacLennan
Publikováno v:
Journal of Sound and Vibration. 110:511-522
The time varied gain (TVG) of a sonar is intended to remove the range dependence of echo strength. The conventional “40 log R” and “20 log R” TVG functions, which apply to single and distributed targets respectively, provide exact compensatio
Autor:
D.N. MacLennan
Publikováno v:
Fisheries Research. 1:23-33
Present techniques for predicting the drag of fishing nets are analysed. They are inaccurate when applied to modern demersal trawls, and they overestimate the significance of netmouth geometry. The measured net drag at constant speed does not vary si
Autor:
D.N. MacLennan
Publikováno v:
Fisheries Research. 2:160-162
Akademický článek
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Akademický článek
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Publikováno v:
Deep Sea Research and Oceanographic Abstracts. 18:543-544
Autor:
D.N. MacLennan
Publikováno v:
Electronics Letters. 3:139
A circuit is described which allows full-wave rectification of from 1.5mV to 5V in amplitude, and from 0 to 200 kHz in frequency. A bridge arrangement is used, with four field-effect transistors connected in the arms of the bridge and switched by the