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81.
A. S. Samodurov 《Physical Oceanography》2006,16(3):129-140
We study the dynamic features of propagation of subsurface gravitational lenses and the conditions of changes in the modes
of control over their motion by various internal and external forces. As these forces, we study the action of drag, molecular
and turbulent viscosity due to the presence of internal and external forces, and deceleration caused by the effects of double
diffusion. We also analyze the modes of propagation of small-scale gravitational lenses. The information about these lenses
taken from the literature is supplemented and generalized.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 3–14, May–June, 2006. 相似文献
82.
Miller B.S. Zosuls A.L. Ketten D.R. Mountain D.C. 《Oceanic Engineering, IEEE Journal of》2006,31(1):87-94
Previous research on the cetacean auditory system has consisted mostly of behavioral studies on a limited number of species. Little quantitative physiologic data exists on cetacean hearing. The frequency range of hearing varies greatly across different mammalian species. Differences among species correlate with differences in the middle-ear transfer function. Middle-ear transfer functions depend on the mechanical stiffness of the middle ear and the cochlear input impedance. The purpose of this study was to measure the middle-ear stiffness for the bottlenose dolphin (Tursiops truncatus), a species specialized for underwater high-frequency hearing and echolocation. Middle-ear stiffness was measured with a force probe that applied a known displacement to the stapes and measured the restoring force. The average middle-ear stiffness in ten dolphin ears was 1.37 N//spl mu/m, which is considerably higher than that reported for most terrestrial mammals. The relationship between middle-ear stiffness and low-frequency hearing cutoff in Tursiops was shown to be comparable to that of terrestrial mammals. 相似文献
83.
84.
A new approach to constraining seawater δ34S and sulphate concentration using francolite‐bound sulphate reveals an abrupt increase in δ34S to +50‰ around the Early–Middle Cambrian boundary. Such high δ34S values are best explained by increased rates of pyrite burial due to ocean anoxia coupled with an increased sensitivity of the ocean sulphate reservoir to perturbations due to low sulphate concentrations of 500–700 μgL?1. We argue that the spread of anoxic waters at this time was partly the result of greenhouse warming related to the eruption of the Kalkarindji Large Igneous Province of northern Australia and that it triggered the collapse of early metazoan reef ecosystems during the latest Early Cambrian. Mass extinctions of the last 260 Myr have all coincided with enhanced volcanic activity, while several are also associated with positive shifts in seawater δ34S. Extending this correlation back in time further implicates volcanically induced climate change as a major determining factor in biosphere evolution. Terra Nova, 18, 257–263, 2006 相似文献
85.
86.
J. C. A. Miller-Jones R. P. Fender E. Nakar 《Monthly notices of the Royal Astronomical Society》2006,367(4):1432-1440
We present a collation of the available data on the opening angles of jets in X-ray binaries, which in most cases are small (≲10°). Under the assumption of no confinement, we calculate the Lorentz factors required to produce such small opening angles via the transverse relativistic Doppler effect. The derived Lorentz factors, which are in most cases lower limits, are found to be large, with a mean >10, comparable to those estimated for active galactic nuclei (AGN) and much higher than the commonly assumed values for X-ray binaries of 2–5. Jet power constraints do not, in most cases, rule out such high Lorentz factors. The upper limits on the opening angles show no evidence for smaller Lorentz factors in the steady jets of Cygnus X-1 and GRS 1915+105. In those sources in which deceleration has been observed (notably XTE J1550−564 and Cygnus X-3), some confinement of the jets must be occurring, and we briefly discuss possible confinement mechanisms. It is however possible that all the jets could be confined, in which case the requirement for high bulk Lorentz factors can be relaxed. 相似文献
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90.
Radiation exposure and Mission Strategies
for Interplanetary Manned Missions (REMSIM) 总被引:1,自引:0,他引:1
C. Cougnet N. B. Crosby S. Eckersley C. Foullon V. Guarnieri S. Guatelli D. Heynderickx A. Holmes-Siedle C. Lobascio S. Masiello P. Nieminen G. Parisi P. Parodi M. A. Perino M. G. Pia R. Rampini P. Spillantini V. Tamburini E. Tracino 《Earth, Moon, and Planets》2004,94(3-4):279-285
Cosmic radiation is an important problem for human interplanetary missions. The “Radiation Exposure and Mission Strategies for Interplanetary Manned Missions–REMSIM” study is summarised here. They are related to current strategies and countermeasures to ensure the protection of astronauts from radiation during interplanetary missions, with specific reference to: radiation environment and its variability; radiation effects on the crew; transfer trajectories and associated fluences; vehicle and surface habitat concepts; passive and active shielding concepts; space weather monitoring and warning systems. 相似文献