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排序方式: 共有378条查询结果,搜索用时 31 毫秒
151.
Toshio Uchida 《Monthly notices of the Royal Astronomical Society》1998,297(1):315-322
The force-free magnetosphere around an obliquely rotating pulsar is studied. The basic equations reduce to two equations for two Euler potentials. One of the Euler potentials is regarded as a generalization of the stream function of the poloidal magnetic field lines in an axisymmetric rotator. Two divergence-free vectors become tangential to the surface on which this Euler potential is constant. 相似文献
152.
153.
154.
Makoto Yoshikawa 《Celestial Mechanics and Dynamical Astronomy》1987,40(3-4):233-272
When asteroids are in the secular resonance 6, the variation of the eccentricity becomes very large. In this paper, the dynamics of this secular resonance 6 is investigated by a simple analytical model, in which the third degree terms of the eccentricity and inclination are taken into account. The eccentricity variations of asteroids located near this resonance are represented clearly by the diagrams of equi-Hamiltonian curves on the plane of
versuse (
the longitude of perihelion of asteroids and Saturn,e: the eccentricity of asteroids). These diagrams predict that the eccentricity of these asteroids suffers a large increase or decrease, and that the secular resonance argument
librates about 0° and 180°. In order to confirm these predictions, numerical integrations are carried out over one million years. By these integrations, it is found that the eccentricity of secular resonant asteroids becomes more than 0.8, and that the libration about 0° also exists, as well as the libration about 180°. The strongly depopulated region in the asteroidal belt, which corresponds to the position of the secular resonance 6, is also explained well by this analytical model. 相似文献
155.
Tsugunobu Nagai Masaynki Kuwashima Makoto Kawamura Tsuyoshi Kohno 《Planetary and Space Science》1979,27(7):1035-1037
It is suggested that the drop out of the 1.2–4 MeV proton flux, observed by the geostationary satellite GMS, was due to the Earthward shift of the particle boundary in all local time. The particle boundary motions are associated with substorm activities. 相似文献
156.
H.-R. Wenk G. Ischia N. Nishiyama T. Uchida 《Physics of the Earth and Planetary Interiors》2005,152(3):191-199
Ringwoodite Mg2SiO4 with spinel structure is an important phase in the earth's mantle transition zone. Controlled deformation experiments showed that ringwoodite underwent ductile deformation when compressed axially at 6-10 GPa and at room temperature in a multianvil D-DIA deformation apparatus. Texture evolution during cyclic compression has been recorded in situ using X-ray transparent anvils with monochromatic synchrotron X-ray diffraction and a two-dimensional detector. Quantitative analysis of the images with the Rietveld method revealed a 1 1 0 fiber texture. By comparing this texture pattern with polycrystal plasticity simulations, it is inferred that {1 1 1}〈 1 0〉 slip is the dominant deformation mechanism in ringwoodite, consistent with high temperature mechanisms observed in other spinel-structured materials. Although strong ringwoodite textures may develop in the transition zone, the contribution to bulk anisotropy is minimal due to the weak single-crystal anisotropy. 相似文献
157.
Nitrate and phosphate uptake kinetics ofChattonella antiqua were examined under light and dark conditions. The uptake kinetics ofC. antiqua followed the Michaelis-Menten equation. The maximal uptake rates (V max) of nitrate and phosphate in the dark were 86 and 93% of those in the light, respectively. The half-saturation constants (K 8 ) were not significantly affected by illumination and were comparable to those of other phytoplankton. However, specific maximal uptake rates ofC. antiqua for these substrates were much smaller than those of other phytoplankton. 相似文献
158.
Atsuhiko Isobe Masafumi Kamachi Yukio Masumoto Hiroshi Uchida Tsurane Kuragano 《Journal of Oceanography》2004,60(2):321-328
The seasonal variation of the Kuroshio transport south of Japan has been investigated using the results of an assimilation
model. Annual and semiannual variations of the transport and dynamic depth anomaly are reconstructed by CEOF (complex orthogonal
empirical function) analysis. In the basin west of the Izu-Ogasawara Ridge, the annual component of the variation propagates
westward with the phase speed of the long Rossby wave associated with the first baroclinic mode. The variation also shows
a similar tendency to that reproduced in a wind-driven, two-layer model with a ridge. This suggests that the annual variation
revealed in the assimilation model is associated with the baroclinic first mode of motion excited above the Izu-Ogasawara
Ridge. Furthermore, it is found that both the semiannual component and the annual component are important members determining
the seasonal variation of the Kuroshio transport south of Japan. The semiannual component is revealed as a double gyre pattern
in the basin west of the Izu-Ogasawara Ridge.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
159.
Makoto Kashiwai 《Journal of Oceanography》1985,41(1):1-10
A self-excited oscillation of tidal flow occurs in a tidal channel-basin system with a narrow and high speed inflowing tidal jet. The mechanism of this oscillation was examined through hydraulic experiments. Results show that the oscillation is caused by alternation in the strength of asymmetric residual circulation caused by a biased supply of vorticity by asymmetric tidal vortex pairs, and that the mechanism of alternation also depends on negative feed-back between the residual circulation and the vorticity supply.The unstable state of the flow suggested the possibility of controlling the tidal current and tidal exchange in the channel-basin system and this was confirmed experimentally. Under fixed tidal conditions and with fixed basin dimensions, the tidal residual circulation was controlled to form two strong clockwise and anticlockwise circulations or a single circulation by changing the shape of the bay entrance. 相似文献
160.