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Том 44, № 12 (2017)
- Год: 2017
- Статей: 9
- URL: https://journals.rcsi.science/1068-3356/issue/view/14118
Article
Behavioral model of macromolecules in a turbulent flow and its analytical consequences
Аннотация
A mathematical dependence relating physicochemical properties of diluted solutions of high-molecular polymers to the increment of the bulk velocity of the turbulent solution flow in comparison with pure solvent is derived. Based on the obtained dependence, boundary conditions of the Toms effect manifestation are deduced.
347-349
Using a plane wave approximation in simulation of radiation distribution in an X-ray Talbot interferometer
Аннотация
This study is devoted to the analysis of the plane-wave approximation applicability to X-ray radiation incident on an object. Based on simple calculations, it is shown that an X-ray tube focal spot 0.4 × 0.8 mm in size at distances of ~1 m can be considered as a point source; however, the plane-wave approximation for such X-ray radiation with energy E = 22keV is valid for radiation source–object distances much longer than 10 m.
350-352
Photoluminescence properties of silicon nanocrystals grown by nanosecond laser ablation of solid-state targets in an inert gas atmosphere
Аннотация
It was found that the photoluminescence intensity decay kinetics of nanocrystalline silicon layers formed by nanosecond laser ablation of crystalline silicon targets in a helium atmosphere exhibit a power-law behavior with an exponent from 0.9 to 1.5, depending on the temperature and luminescence photon energy in the range of 1.4–1.8 eV, which indicates photoexcited carrier recombination controlled by dissipative tunneling processes in silicon nanocrystal ensembles in a suboxide matrix.
353-356
Diffusion filling with fuel gas of high-gain direct-drive cryogenic targets
Аннотация
To provide continuous operation of a reactor based on inertial confinement fusion (ICF), the thermonuclear burn region should be refilled with fuel with a frequency of 1 million targets per day. The first stage in the target production is diffusion filling of polymeric (CH) shells with fuel gas which is deuterium (D2) or deuterium–tritium (DT) mixture. The results of simulation of filling reactor-scale CH-shells (Ø ~ 4 mm) to a pressure of ~1100 atm at 300 K in the mode with a constant pressure gradient are presented. Simple and two-layer shells of compact and porous polymers are considered. The problems of constructing an optimum DT-filling scheme avoiding CH-shell fracture due to tritium beta decay are discussed.
357-364
365-367
Charged particles bunch–accelerator extraction window matching
Аннотация
The criterion for matching the charged particle bunch with the accelerator beam extraction window, which consists in minimizing the emittance of the accelerated beam extracted through a metal foil, is derived using the distribution function for moving particles scattered on foil nuclei. A technique for constructing the phase portrait of the scattered bunch and the criterion for minimizing its area (emittance) are presented. The formula relating the emittances of incident and scattered bunches and the ellipse equation describing the phase portrait of the matched bunch are derived.
368-370
Visible luminescence enhancement methods in SiGe/Si heterostructures
Аннотация
The possibility of increasing the photoluminescence signal of Si1−xGex/Si quantum wells in the visible spectral range due to a change in the conduction band structure and the interaction of many-body states with plasma oscillations of metal nanoparticles is studied. The sample band structure was controlled using a uniaxial strain of ∼10−4. It is found that such an approach allows an increase in the emission intensity of biexcitons in the quantum well (x = 9%) by a factor of 2.4 at a temperature of 5 K. Metal nanoparticles deposited on the sample surface with a protective layer thickness of 20 nm allowed us to increase the luminescence intensity of quantum wells approximately by a factor of 2.7.
371-373
Interaction of pulsed laser radiation with a polycarbonate-based composite
Аннотация
Abstract—The interaction of pulsed laser radiation with foil-clad polycarbonate containing diffraction gratings is studied. It is found that the laser beam reflected from diffraction gratings is selffocused in polycarbonate bulk and becomes a seed for changing the polycarbonate structure, which leads to the glass transition and growth of ordered structures with symmetry features, which gives rise to the light dispersion effect in composites. A probable formation mechanism of ordered structures in polycarbonate during irradiation is proposed.
374-379
γ-families with halos observed by X-ray emulsion chamber in EAS and the estimate of the p+He fraction in primary cosmic rays at E0 = 1–100 PeV
Аннотация
The experimental γ-families in which events called “halos” were detected using X-ray emulsion chambers (XRECs) of the PAMIR experiment are described. The halo nature is explained within the standard model of nuclear interactions. Based on events with halo, the fraction of p+He in primary cosmic rays (PCR) was estimated. It is shown that the PCR mass composition remains mixed in the range E0 = 1–100 PeV.
380-384