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91.
The nonlinear problem of the expansion of a uniform spherical cluster, which consists of ions with a charge sufficient to
accelerate relativistic energies has been solved precisely. It has been shown that relativistic non-linearity is responsible
for the formation of an expanding shell-type structure. The space-time and energy characteristics of the relativistically
exploding cluster have been found. 相似文献
92.
R. N. Nurmukhametov A. V. Shapovalov A. M. Sergeev A. I. Kovalev N. S. Kushakova I. A. Khotina 《Journal of Applied Spectroscopy》2011,78(3):344-351
Absorption spectra and fluorescence parameters (spectra, quantum yields, and lifetimes) were obtained for a number of branched
oligophenylenes (OPh) with long-wavelength chromophores such as p-quaterphenyl (OPh4-2), p-pentaphenyl (OPh5), and p-hexaphenyl (OPh6) and for oligofluorenylphenylenes (OFl) in solutions and films. It is demonstrated that the absorption spectrum
of OPh4-2 is a superposition of p-quaterphenyl, p-terphenyl, and diphenyl absorption bands taken in a ∼3:2:2 ratio. The obtained OPh5 and OPh6 absorption and fluorescence
spectra are shown to be determined mainly by the longest-wavelength chromophores, p-pentaphenyl and p-hexaphenyl, respectively. It is demonstrated that the obtained compounds contain traces of impurities with fluorescence at
longer wavelengths than that of the base material. The branched oligomers exhibit high fluorescence quantum yields in solutions,
those for OPh5 and OPh6 reaching 1. Transparent fluorescent films were produced from all of the synthesized oligomers. 相似文献
93.
The induced modulation of the exciton density in a system consisting of spatially separated layers of a two-dimensional electron
gas and indirect dipolar excitons is studied theoretically. In particular, it is shown that an external potential causes Friedel
oscillations in the density of excitons due to their interaction with electrons. Possibilities for experimental observation
of this effect are briefly discussed. 相似文献
94.
A. I. Kuklin A. D. Rogov Yu. E. Gorshkova P. K. Utrobin Yu. S. Kovalev A. V. Rogachev O. I. Ivankov S. A. Kutuzov D. V. Soloviov V. I. Gordeliy 《Physics of Particles and Nuclei Letters》2011,8(2):119-128
The results of experimental and computer-modeling investigations of neutron spectra and fluxes obtained with cold and thermal
moderators at the IBR-2 reactor (Joint Institute for Nuclear Research (JINR), Dubna) are presented. These studies are for
the YuMO small-angle neutron scattering (SANS) spectrometer (IBR-2 beamline 4). The neutron spectra have been measured for
two methane cold moderators for the standard configuration of the SANS instrument. The data from both moderators under different
conditions of their operation are compared. The ratio of experimentally determined neutron fluxes of cold and thermal moderators
is shown at different wavelengths. Monte Carlo simulations have been carried out to determine the spectra for cold-methane
and thermal moderators. The results of calculations of the ratio of neutron fluxes of cold and thermal moderators at different
wavelengths are demonstrated. In addition, the absorption of neutrons in the air gaps on the way from the moderator to the
investigated sample is presented. SANS with the protein apoferritin was done with both cold methane and a thermal moderator
and the data were compared. The prospects for the use of a cold moderator for a SANS spectrometer at IBR-2 are discussed.
The advantages of using the YuMO spectrometer with a thermal moderator with respect to the tested cold moderator are shown. 相似文献
95.
96.
97.
The dynamics of the ferromagnetic order parameter in thin magnetic films is strongly affected by the magnetomechanical coupling at certain resonance frequencies. By solving the equation of motion of the coupled mechanical and magnetic degrees of freedom we show that the magnetic field induced magnetization switching can be strongly accelerated by the lattice and illustrate the possibility of magnetization reversal by mechanical actuation. 相似文献
98.
We experimentally show that, when stimulated Brillouin scattering is generated in optical fiber by use of monochromatic cw pump radiation, the transmitted pump radiation exhibits spectral broadening that is much narrower than the classical homogeneous gain-narrowed Brillouin bandwidth. The bandwidth is practically independent of the pump strength, fiber characteristics, and the waveguide-induced inhomogeneously broadened bandwidth of the Stokes emission. We show that these properties arise from strong parametric coupling of the Stokes and pump signals in the pump-depletion region. 相似文献
99.
The conversion of 0.1–2.0 M aqueous ethanol solutions in the carbonate electrolyte by treatment with a microdischarge at an anode made of the AMg-6 aluminum–magnesium alloy was studied. It was shown that the microdischarge treatment leads to degradation of ethanol yielding hydrogen, carbon monoxide, 1–4 hydrocarbons, methanol, formaldehyde, acetaldehyde, 1,2-propylene glycol, 2,3-butylene glycol, water, and acetic acid. The mechanism of relevant processes is discussed, which suggests a multiplicity of ethanol degradation pathways in vapor–gas bubbles. 相似文献
100.
The theory of the coherent photogalvanic valley Hall effect in two-dimensional systems with the Dirac spectrum of charge carriers is formulated. The study deals with a two-dimensional sample irradiated by two electromagnetic waves, at the fundamental and doubled frequencies. Both frequencies exceed the band gap of the material, whereas the wave with the fundamental frequency having circular polarization and a high intensity is taken into account in a nonperturbative manner. The wave at the doubled frequency is linearly polarized and the electrical conductivity of the two-dimensional system is calculated with respect to it. The effect under study manifests itself as the dc Hall current in the direction orthogonal to the electric field of the weak electromagnetic wave. It is assumed that, in equilibrium, the sample is in the insulating state with the completely occupied valence band and empty conduction band. The strong electromagnetic wave induces a nonequilibrium filling of the bands and the system passes to a strongly nonequilibrium steady state. The behavior of the Hall current in the case of nonequilibrium distribution functions is analyzed both including and disregarding the intraband relaxation and interband recombination. 相似文献