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291.
In this paper we prove the existence of ring-type bounded motion in an isolated system consisting of a massive point particle and a homogeneous cube. We study the case of planar motion where the particle moves in a symmetry plane of the cube and we use a rotating frame of reference with its center at the mass center of the cube and its axes coinciding with the symmetry axes of the cube. We prove that, for negative values of the total energy and properly chosen values of the total angular momentum, the relative distance of the bodies has an upper and a lower bound-i.e., the regions of possible motion lie inside an annulus around the cube (motion inside a ring or an island). 相似文献
292.
D.G. King-Hele 《Planetary and Space Science》1985,33(10):1145-1153
The satellite 1967-11G, which had an orbital inclination of 40°, passed through the 14th-order resonance with the Earth's gravitational field in 1974. The changes in its orbital inclination at resonance have been analysed to obtain values for four lumped 14th-order harmonics in the geopotential, with accuracies equivalent to about 5 cm in geoid height. Analysis of the eccentricity was also attempted, but did not yield useful results.As no previous satellite analysed at 14th-order resonance has had an inclination near 40°, the results have proved to be valuable in determining individual 14th-order harmonics in the geopotential. 相似文献
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295.
The gray crystalline hematite at Meridiani Planum first discovered by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) instrument occurs as spherules that have been interpreted as concretions. Analysis of the TES and mini-TES spectra shows that no 390 cm−1 feature is present in the characteristic martian hematite spectrum. Here, we incorporate the mid-IR optical constants of hematite into a simple Fresnel reflectance model to understand the effect of emission angle and crystal morphology on the presence or absence of the 390 cm−1 feature in an IR hematite spectrum. Based on the results we offer two models for the internal structure of the martian hematite spherules. 相似文献
296.
X. Bai T.K. Gaisser A. Karle K. Rawlins G.M. Spiczak Todor Stanev 《Astroparticle Physics》2006,25(6):361-367
The muon flux at the South Pole was measured for five zenith angles, 0°, 15°, 35°, 82.13° and 85.15° with a scintillator muon telescope incorporating ice Cherenkov tank detectors as the absorber. We compare the measurements with other data and with calculations. 相似文献
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298.
It is pointed out that the total amount of microwave radiation that could possibly be generated by all the graphite needles in space would be considerably smaller than the observed total energy of the cosmic microwave background radiation. The question of relevant optical depth of the cloud containing the needles has been examined. It is found that the optical depth is not sufficiently large for the cloud to radiate like a black body. 相似文献
299.
During a campaign of optical observations at high latitude, a bi-dimensional study of the wave structure of the OH layer has been performed in December 1981 from Sodankyla (Finland). This site is one of the three stations of the EISCAT ionosphere sounding system. It has been found that a wave field covering an area of 1 million km2 may extend to latitudes as high as 70°N. The OH wave structure shows many similarities with noctilucent clouds. The fairly large horizontal wavelength, of the order of 40 km cannot easily be explained by a wave motion at an interface. The observed wave structure seems to be a result of the propagation of an internal gravity wave in the 80–100 km region. This wave structure was often recorded during the same time as an active aurora was present. As a result, it appears that the perturbation might be correlated with particle precipitations at auroral latitudes. 相似文献
300.
Methods of Hierarchical Control of Water Quality Taking into Account Manipulations of the Center and Countermoves of Enterprises 总被引:2,自引:1,他引:1
Methods of hierarchical control including manipulations of a Center and the countermove of enterprises are considered using as an example a dynamic two-level model of river water quality control in the presence of point pollution sources and in the absence of nonpoint sources. 相似文献