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931.
A. Gil M.V. Alania 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
We study the temporal evolution of the power rigidity spectrum of the first (27 days) and the second (14 days) harmonics of the 27-day variation of the galactic cosmic ray intensity measured by neutron monitors in the period of 1965–2002. The rigidity spectrum of these variations can be approximated by a power law. We show the rigidity spectra of the first and the second harmonics of the 27-day variation of the galactic cosmic ray intensity have similar time profiles. These spectra are hard (γ ≈ 0.5 ± 0.1) and soft (γ ≈ 1.1 ± 0.2) during solar maximum and minimum activity, respectively. We ascribe this to the alternation of the sizes of the modulation regions responsible for the 27-day variation of the galactic cosmic ray intensity in different epochs of solar activity. Especially, the average radial sizes of the modulation regions of the 27-day variation and the heliolatitudinal extension of the heliolongitudinal asymmetry are smaller during solar minimum than during solar maximum. We show also, that the temporal changes of the power rigidity spectra of the first and the second harmonics of the 27-day variation of the galactic cosmic ray intensity are in a negative correlation with the changes of the rigidity spectrum of the corresponding 11-year variation. 相似文献
932.
To calculate the unsteady helicopter motion, we propose a simplifying approach consisting in the fact that the numerical solution
of equations of nonlinear nonstationary aerodynamics and flight dynamics are made successively in time intervals. As an example,
the results of calculating the helicopter motion in descent are presented. The mathematical model and algorithm can be used
for calculating the unsteady motion of different helicopters. 相似文献
933.
R. Devaraj K. Sankarasubramanian Surekha Kamath 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Multi-slit spectropolarimeter is a next-generation spectropolarimeter to obtain vector magnetic field information at high spatial, spectral, and temporal resolution for studying the magnetic structures on the Sun. Once developed, it can be used as ground based instrument at solar observatories, also as a space payload for various solar missions. A high spectral resolution is invariably an important parameter for accurate vector magnetic field measurements and faster cadence is required for the study of dynamical evolution of structures (e.g., solar flares, sunspots etc.) on the Sun and hence better understanding on the physics behind their evolution. 相似文献
934.
A. I. Golovanov 《Russian Aeronautics (Iz VUZ)》2010,53(3):243-249
The constitutive relations and plastic flow rule are derived from the thermodynamics equations. The known procedures of determining
the plastic strain rate value are described. A calculation algorithm is presented that is based on the incremental loading,
linearization of the virtual power equation and the projection method. A numerical example is presented. 相似文献
935.
In this paper, the results of an experimental study concerning average heat transfer in an annular channel with flow swirling
by an endless screw and spherical grooves on the convex surface are presented. Also analyzed is the heat and hydraulic efficiency
of grooves application under conditions being considered. 相似文献
936.
937.
938.
Ch. I. Chaban R. T. Ripetskyj E. L. Kordyum N. A. Kit 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,23(12):2011-2016
Under gravistimulation, dark-grown protonemata of Pottia intermedia revealed negative gravitropism with a growth rate of approximately 28 μm·h−1 at room temperature (20 °C). In 7 days, the protonema formed a bundle of vertically oriented filaments. At an elevated temperature (30 °C), bundles of vertically growing filaments were also formed. However, both filament growth rate and amplitude of the gravicurvature were reduced. Red light (RL) irradiation induced a positive phototropism of most apical protonemal cells at 20 °C. In a following period of darkness, approximately two-thirds of such cells began to grow upward again, recovering their negative gravitropism. RL irradiation at the elevated temperature caused a partial increase in the number of protonemal cells with negative phototropism, but the protonemata did not exhibit negative gravitropism after transfer to darkness. The negative gravitropic reaction was renewed only when protonemata were placed at 20 °C. A dramatic decrease in starch amount in protonemal apical cells, which are sensitive to both gravity and light, occurred at the higher temperature. Such a decrease may be one of the reasons for the inhibition of the protonemal gravireaction at the higher temperature. The observation has a bearing on the starch-statolith theory. 相似文献
939.
K Kobayashi T Kaneko T Saito 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,24(4):461-464
A wide variety of organic compounds, which are not simple organics but also complex organics, have been found in planets and comets. We reported that complex organics was formed in simulated planetary atmospheres by the action of high energy particles. Here we characterized the experimental products by using chromatographic and mass spectrometric techniques. A gaseous mixture of CO, N2 and H2O was irradiated with high energy protons (major components of cosmic rays). Water-soluble non-volatile substances, which gave amino acids after acid-hydrolysis, were characterized by HPLC and mass spectrometry. Major part of the products were complex compounds with molecular weight of several hundreds. Amino acid precursors were produced even when no water was incorporated with the starting materials. It was suggested that complex molecules including amino acid precursors were formed not in solution from simple molecules like HCN, but directly in gaseous phase. 相似文献
940.
A. Peraiah 《Space Science Reviews》1999,87(3-4):465-538
We have reviewed the principle of invariance, its applications and its usefulness for obtaining the radiation field in semi-infinite
and finite atmospheres. Various laws of scattering in dispersive media and the consequent radiation field are studied. The
H-functions and X- and Y-functions in semi-infinite and finite media respectively are derived in a few cases. The Discrete
Space Theory (DST) which is a general form of the Principle of Invariance is described. The method of addition of layers with
general properties, is shown to describe all the properties of multiple scattering. A few examples of the application of DST
such as polarization, line formation in expanding stellar atmospheres, etc., and a numerical analysis of DST are presented.
Other developments in the theory of radiative transfer are briefly described.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献