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51.
We use the equations of nonlinear theory of shallow shells to solve the problem of stability of thin elastic isotropic cylindrical
shells, with small initial shape imperfections, that are under the action of external uniform pressure. The problem solution
is constructed by the Rayleigh-Ritz method with the approximation of the shell midsurface displacement by double functional
sums in trigonometric and beam functions. The system of nonlinear algebraic equations is solved by using the methods of continuation
with respect to a close-to-best parameter. For the initial imperfections of the shells, we use their normalized deflections
from the limit points of overcritical branches of the loading trajectories. We consider various cases of the shell fixation
and support under loading by lateral and hydrostatic uniform pressure. We also construct the range of values of the critical
pressure, which, with the maximal deviation of the shell shape from the cylindrical shape up to 30%, covers practically all
known experimental data. 相似文献
52.
53.
Optics and Spectroscopy - Studies published in the period from 2014 to 2018 that are aimed at creating nondispersive and photoacoustic IR gas analyzers with LED radiation sources based on... 相似文献
54.
Matveev Vladimir B. Semenov-Tian-Shansky Michel 《Letters in Mathematical Physics》2019,109(6):1269-1270
Letters in Mathematical Physics - 相似文献
55.
Russian Physics Journal - The work of external sources uniformly distributed in a homogeneous plasma and exciting in it a circularly polarized wave with phase velocity lower than the velocity of... 相似文献
56.
Albrecht J Matveev AT Strempfer J Habermeier HU Shantsev DV Galperin YM Johansen TH 《Physical review letters》2007,98(11):117001
Anisotropic penetration of magnetic flux in MgB(2) films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, the anisotropy of the critical current being 6%. At lower temperatures the penetration occurs via abrupt dendritic avalanches that preferentially propagate perpendicular to the surface steps. This inverse anisotropy in the penetration pattern becomes dramatic very close to 10 K where all flux avalanches propagate in the strongest pinning direction. The observed behavior is fully explained using a thermomagnetic model of the dendritic instability. 相似文献
57.
We study a system of one-dimensional electrons in the regime of strong repulsive interactions, where the spin exchange coupling J is small compared with the Fermi energy, and the conventional Tomonaga-Luttinger theory does not apply. We show that the tunneling density of states has a form of an asymmetric peak centered near the Fermi level. In the spin-incoherent regime, where the temperature is large compared to J, the density of states falls off as a power law of energy epsilon measured from the Fermi level, with the prefactor at positive energies being twice as large as that at the negative ones. In contrast, at temperatures below J the density of states forms a split peak with most of the weight shifted to negative epsilon. 相似文献
58.
The procedure of aperture synthesis by an incoherent source during displacement of the receiving system in space is considered.
The advantages of the method are the possibility of aperture synthesis with the help of antenna arrays consisting of two receivers
and its applicability to both the source of a quasimonochromatic signal and that possessing a continuous spectrum. The method
is applicable with the same limitations as the known methods using the procedures of signal phasing. The results of mathematical
simulation of the synthesis upon location of two sources with close frequencies at different distances and in the presence
of noise, as well as the results of the in situ experiment with a reverberation interference, are given. The algorithm for
decreasing the time of aperture synthesis without resolution deterioration is proposed and tested in situ. 相似文献
59.
We have developed a nonperturbative theory of the energy losses by fast heavy structured ions in their collisions with neutral complex atoms by taking into account all of the possible, including multiple, excitations and ionizations of both projectile and target. We have been able to achieve a significant simplification of the problem by considering multielectron targets and by restricting our analysis to highly charged structured ions with charges much larger than unity, when the characteristic size of the electron coat of the projectile ion is much smaller than that of the neutral target atom. The errors in the approximations used and in the calculations of inelastic cross sections are estimated. We have derived formulas for the effective stopping similar to the well-known Bethe-Bloch formulas. To illustrate the contribution from multielectron excitations of the ion coat to the effective stopping, we make a comparison with the calculations based on the perturbation theory. The energy losses of U q+ (10 ≤ q ≤ 70) ions in their collisions with argon atoms and the energy losses of Pb and Bi ions on several targets have been calculated. A comparison with experiment is made. 相似文献
60.
A nonperturbatve theory of energy losses of fast heavy multiply charged structural ions in collisions with neutral complex atoms is elaborated with allowance for simultaneous excitations of ionic and atomic electron shells. Formulas for the effective deceleration that are similar to the well-known Bethe-Bloch formulas are derived. By way of example, the energy lost by partially stripped U q+ ions (10 ≤ q ≤ 70) colliding with argon atoms and also the energy lost by Au, Pb, and Bi ions colliding with various targets are calculated. The results of calculation are compared with experimental data. 相似文献