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521.
The near wave field generated by the travelling atmospheric pressure zone over a stratified fluid is studied within the framework of the linear theory of long waves allowing for the Coriolis force. The exact solution of the problem as a set of single integrals is deduced for the model distribution of pressures. The characteristics of the near wave field have been computed for the Väisälä-Brunt frequency profile takeu from observations. Their dependences on the geographical latitude and the wave generator travelling rate are analysed.Translated by Mikhail M. Trufanov. 相似文献
522.
An elongated sea bed depression (pit), 80 by 125 m and 10 m deep located on the Grand Banks of Newfoundland was identified on high resolution surficial geophysical survey lines and investigated using a manned submersible. The pit occurs at the termination of a long (greater than 3 km) iceberg scour, 1.5 m deep, and 80 m wide in 91 m of water. It is similar to other depressions in the region that indent the sea bed up to seven times deeper than the surrounding deepest iceberg furrows. The pit is interpreted to be the sea bed response to impact and loading by a rolling and grounding iceberg. The iceberg scour and pit appear to be of recent origin. 相似文献
523.
A. A. Bezborodov S. L. Gokchen V. N. Eremeev I. T. Konuk A. K. Saidam E. M. Tirasin 《Physical Oceanography》1991,2(3):227-231
The hydrological and hydrochemical structures of the upper 300 m water column of the Black Sea in autumn 1988 have been studied. Regularities in the distribution of the physico-chemical characteristics in the zone of interaction between aerobic and anaerobic waters as well as the topography of the H2S zone boundary and its connection with a certain density gradient have been found.Translated by Mikhail M. Trufanov. 相似文献
524.
525.
Reproductive variability in North Sea plaice, sole, and cod 总被引:4,自引:1,他引:4
Rijnsdorp A. D.; Daan N.; van Beek F. A.; Heessen H. J. L. 《ICES Journal of Marine Science》1991,47(3):352-375
526.
M. V. Ramana 《Geo-Marine Letters》1986,6(1):1-5
Satellite imagery and offshore magnetic data were analysed to correlate regional tectonic elements on the inner continental
shelf off Konkan and the adjacent Deccan plateau. Three statistically important lineament trends—N-S, WNW-ESE and ENE-WSW—that
prevail on land are correlatable well with the offshore trends. This positive correlation suggests simultaneous deformation.
The major magnetic lineament observed off Jaigad Bay, west coast of India, may be the extension of onshore lineaments. The
correlation of both the offshore and onshore trends indicates that the fracture pattern of the crystalline basement has also
controlled the offshore structural pattern. 相似文献
527.
A method is proposed to study the transport of a passive additive in the atmospheric surface layer with the use of the atmospheric transfer function. This method makes it possible to estimate the spatial distribution of the concentration of a passive additive in the atmospheric surface layer from the additive’s surface source without experimentally determining the vertical profile of the transport coefficient or without resorting to various hypotheses for the character of its behavior. The transfer function, which contains the information on the wind-field structure, can be obtained from simple one-point measurements of surface-and air-temperature fluctuations and from subsequent spectral processing of the data. The effects of the wind-velocity profile and turbulence on the spatial distribution of additive concentration are assessed. This method allows one to simplify experiments during development and verification of the models of atmospheric diffusion. This method may also be useful in emergency situations to predict the propagation of hazardous additives. 相似文献
528.
Adaptive optimal control of an autonomous underwater vehicle in the dive plane using dorsal fins 总被引:1,自引:0,他引:1
In this paper, adaptive control of low speed bio-robotic autonomous underwater vehicles (BAUVs) in the dive plane using dorsal fins is considered. It is assumed that the model parameters are completely unknown and only the depth of the vehicle is measured for feedback. Two dorsal fins are mounted in the horizontal plane on either side of the BAUV. The normal force produced by the fins, when cambered, is used for the maneuvering. The BAUV model considered here is non-minimum phase. An indirect adaptive control system is designed for the depth control using the dorsal fins. The control system consists of a gradient based identifier for online parameter estimation, an observer for state estimation, and an optimal controller. Simulation results are presented which show that the adaptive control system accomplishes precise depth control of the BAUV using dorsal fins in spite of large uncertainties in the system parameters. 相似文献
529.
We present the results of numerical experiments aimed at the simulation of the circulation of waters and transport of impurities
in the Balaklava Bay for typical wind conditions established on the basis of the analysis of the data of in-situ measurements. The currents are computed by using the nonlinear σ-coordinate model. The specific features of the integral
circulation and three-dimensional structure of the current field are investigated. The statistical characteristics of currents
are estimated on the basis of the in-situ data on winds and model calculations. Possible scenarios of propagation of impurities from the coastal sources are analyzed
for various hydrodynamic conditions. It is shown that the localized eddy structures in the current fields (in combination
with the zones of intense vertical motion) can result in a complex character of the transport of substances in the bay and
lead to the formation of local regions of maximum concentrations of impurities on the boundary of the north and central parts
of the bay.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 43–58, July–August, 2005. 相似文献
530.
Diet restriction induced autophagy: a lysosomal protective system against oxidative- and pollutant-stress and cell injury 总被引:1,自引:0,他引:1
Moore MN 《Marine environmental research》2004,58(2-5):603-607
Nutrient deprivation or dietary restriction (DR) confers protection against ageing and stress in many animals and induced lysosomal autophagy is part of this mechanism. The effects of dietary restriction on the toxicity of copper and the polycyclic aromatic hydrocarbon phenanthrene have been investigated in the common marine mussel Mytilus edulis. The findings show that DR-induced autophagy facilitates the recovery of the digestive gland (i.e., molluscan liver analogue) from cell injury caused by both copper and phenanthrene. It is inferred that DR-induced autophagy and lysosomal proteolysis results in improved cellular "housekeeping" through the more efficient removal of oxidatively and pollutant damaged proteins (e.g., protein carbonyls, protein adducts, etc.) and that this contributes to stress resistance. 相似文献