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941.
The apparent yearly precession of the solar globe has been defined and described in some detail. Line-of-sight velocities less than ±18 m s-1 occur at the solar disk. The importance of the line-of-sight component of the precession in general, and as a test velocity in contemporary photospheric velocity research is pointed out. 相似文献
942.
Petr Vaníček 《Astrophysics and Space Science》1971,12(1):10-33
The concept of spectral analysis using least-squares is further developed to remove any undesired influence on the spectrum. The influence of such a systematic noise can be eliminated without the necessity of knowing the magnitudes of the noise constituents. The technique can be used for irregularly spaced as well as equidistantly spaced data. The response to random noise is found to be constant in the frequency domain and its expected level is derived. Presence of random noise in the analyzed time series is shown to transform the spectrum merely linearly. Examples of applications of the technique are presented. 相似文献
943.
Pavel Voráček 《Astrophysics and Space Science》1979,65(2):397-413
From the general theory of relativity a relation is deduced between the mass of a particle and the gravitational field at the position of the particle. For this purpose the fall of a particle of negligible mass in the gravitational field of a massive body is used. After establishing the relativistic potential and its relationship to the rest mass of the particle, we show, assuming conservation of mass-energy, that the difference between two potential-levels depends upon the value of the radial metric coefficient at the position of an observer. Further, it is proved that the relativistic potential is compatible with the general concept of the potential also from the standpoint of kinematics. In the third section it is shown that, although the mass-energy of a body is a function of the distance from it, this does not influence the relativistic potential of the body itself. From this conclusion it follows that the mass-energy of a particle in a gravitational field is anisotropic; isotropic is the mass only. Further, the possibility of an incidental feed-back between two masses is ruled out, and the law of the composition of the relativistic gravitational potentials is deduced. Finally, it is shown, by means of a simple model, that local inhomogeneities in the ideal fluid filling the Universe have negligible influence on the total potential in large regions. 相似文献
944.
Pavel Voráček 《Astrophysics and Space Science》1989,161(1):165-166
A possible solution is presented of the issue of the ascertained zero cosmological constant in connection to its high value expected from the existence of vacuum energy density. The answer should be that in the metric space the virtual particle pairs arise together with a correlated negative quantum energy defect, so that the total mass-energy of every pair precisely equals zero. The various observed phenomena can still be explained. 相似文献
945.
946.
947.
Solar Physics - In this paper we examine the elemental composition of the 0.1?–?1 MeV?nucleon?1 interplanetary heavy ions from H to Fe in corotating interaction... 相似文献
948.
949.
M. J. Reiner K.-L. Klein M. Karlický K. Jiřička A. Klassen M. L. Kaiser J.-L. Bougeret 《Solar physics》2008,249(2):337-354
We report here on the solar origin of distinctive radiation characteristics observed for a decametric type III solar radio burst that was associated with a major solar flare and CME on 11 April 2001. The associated decimeter (Ond?ejov) and meter (Potsdam) wavelength emissions, as well as the GOES soft X-ray lightcurve, suggest that there were two successive events of energy release and electron acceleration associated with this solar eruption. The Nançay radioheliograph images and additional evidence of plasmoid propagation suggest that the second event of electron acceleration resulted from coronal reconfigurations, likely caused by the erupting CME. These observational analyses provide new insights into the physical origin of the distinguishing characteristics of complex type III-like radio emissions that are typically observed at decameter wavelengths during major solar eruptive events. 相似文献
950.
Stephen A. Norton Randall H. Perry Jasmine E. Saros George L. JacobsonJr. Ivan J. Fernandez Jiří Kopáček Tiffany A. Wilson Michael D. SanClements 《Journal of Paleolimnology》2011,46(1):107-122
The sediment record from a 5.3-m core from Sargent Mountain Pond, Maine USA indicates strong co-evolutionary relationships
among climate, vegetation, soil development, runoff chemistry, lake processes, diatom community, and water and sediment chemistry.
Early post-glacial time (16,600–12,500 Cal Yr BP) was dominated by deposition of mineral-rich sediment, low in organic matter
and secondary hydroxides of Al and Fe; pollen indicate tundra conditions; diatom taxa indicate pH between 7.5 and 8, and total
P concentrations of about 25 μg L−1, favoring higher productivity. Chemical weathering was rapid, with high alkalinity, pH, Ca, and P in runoff. As climate ameliorated,
about 12,500 Cal Yr BP, forest vegetation became established; soils would have developed vertical zonation, including organic
matter accumulation, and incipient podzolic horizons, with accumulating secondary hydroxides of Al and Fe that sequestered
P in the soils. Labile minerals (primarily apatite, Ca5(PO4)3(OH,F,Cl)) became depleted in the soil, further reducing the supply of P to the lake. Dissolved organic carbon (DOC) from
soil organic matter mobilized Al and Fe to the lake where Al(OH)3 (primarily) and Fe(OH)3 (minor) were precipitated. The sedimenting hydroxides adsorbed P from the water column, further reducing bioavailable P.
These long-term trends of moderating climate, and changing terrestrial biology, soils, and aquatic chemistry and phytoplankton
were interrupted by the 1,000-year long Younger Dryas cooling, which led to a temporary reversal of these processes, a period
that ended with the major onset of Holocene warming. The sequestration of P by soils would have strengthened because of long-term
soil acidification and pedogenesis. The lake was transformed from a more productive, high P, high pH, low DOC system into
an oligotrophic, relatively low P, acidic, humic lake over a period of 16,600 years, a natural trend that continues. In contrast
to many human-affected lakes that become increasingly eutrophic, many lakes become more oligotrophic during their history.
The precursors for that are: (1) absence of human land-use in watersheds, (2) bedrock lithology and soil with a paucity of
soluble Ca-rich minerals, and (3) vegetation that promotes the accumulation of soil organic matter, podzolization, and increased
export of metal-DOC complexes, particularly Al. 相似文献