The relaxation times of localized states of antimony donors in unstrained and strained germanium uniaxially compressed along the 111 crystallographic direction are measured at cryogenic temperatures. ...The measurements are carried out in a single-wavelength pump–probe setup using radiation from the Novosibirsk free electron laser (NovoFEL). The relaxation times in unstrained crystals depend on the temperature and excitation photon energy. Measurements in strained crystals are carried out under stress bar
S
> 300, in which case the ground-state wavefunction is formed by states belonging to a single valley in the germanium conduction band. It is shown that the application of uniaxial strain leads to an increase in the relaxation time, which is explained by a decrease in the number of relaxation channels.
The first stage of the linear accelerator of the Siberian Circular Photon Source (SKIF) accelerator facility has been successfully commissioned at the Budker Institute of Nuclear Physics, Siberian ...Branch, Russian Academy of Sciences (BINP). This test accelerator facility includes the radiofrequency (RF) gun, magnet system, RF accelerating structures, and diagnostic and control system elements. The aim of the work at the facility is to verify the correctness of solutions chosen for the accelerator design, as well as to get operation experience and to measure the beam parameters that will determine the successful work of the overall SKIF complex. This article describes the main subsystems of the test accelerator facility and briefly presents the first operation results concerning the beam parameters.
γ'Ni
3
Al-based casting alloys have a lower density, higher melting point and resistance to oxidation, and a higher ceiling of operating temperatures than modern heat-resistant nickel alloys. The ...article discusses the features of the electronic structure and crystallization of domestic (such as VKNA/VIN) and the most advanced foreign (γ' + γ) low-alloyed γ'Ni
3
Al-based alloys (
IC
type), and experimental data on the nature of the structures formed during directional crystallization of alloys with different types of alloying and on the nature of the distribution of components in the γ'Ni
3
Al and γNi phases and structural components in the cellular-dendritic structure of single crystals with 〈111〉 and 〈001〉 crystallographic orientation are presented. The influence of heat treatment on the microstructure, distribution of alloying elements, and mechanical properties of the VKNA type alloys is investigated in a wide range of temperature–time parameters. A comparative analysis of the effect of temperature and duration of heat treatment and cooling rate after heat treatment on the heat resistance of alloys showed that, unlike other Ni
3
Al-based alloys, for single crystals from the VKNA type economically alloyed alloys and parts made from them (uncooled working blades of aviation gas turbine engines, nozzle apparatuses, jet nozzle spacers, and other parts of the hot path of gas turbine engines), a short-term heat treatment (1150°C/1 h) is necessary and sufficient to relieve casting stresses. The alloys demonstrate high heat resistance at 1100–1200°C and the ability to withstand short-term casting temperatures up to 1250–1300°C.
The article deals with the methodological issues of data preparation for the human capital block of the dynamic input-output model of the Russian economy and analyzes the results of a long-term ...forecast prepared based on this model.
A series of copolymers of
N
-methyl-
N
-vinylacetamide and
N
-methyl-
N
-vinylamine hydrochloride with an average content of charged groups of (4.4 ± 0.2) mol % and molecular mass in the range of ...22 <
M
× 10
–3
, g/mol < 630 are synthesized and characterized. Fractions are studied by sedimentation-diffusion methods in 0.2 mol/L NaCl under almost suppressed polyelectrolyte effects. In salt-free aqueous solutions, their viscous flow is investigated and intrinsic viscosity is determined as η ≡ lim(∂lnη
r
/∂
c
) at
c
→ 0. The results are compared with the previous data obtained for the copolymer containing (15.7 ± 0.5) mol % of charged groups and the homopolymer. It is shown that the type of intrinsic viscosity dependence on the molecular mass of the copolymer containing 4.4 mol % of charged groups is typical of chains manifesting intrachain volume interactions, while at a 15.7 mol % content of charged groups the type of the dependence is characteristic of chains demonstrating intrachain short-range effects; hence, the chains behave as rigid-chain, permeable. The statistical segment lengths of copolymer macromolecules in salt-free solutions and in 0.2 mol/L NaCl are determined. The data are analyzed in terms of the normalized Kuhn–Mark–Houwink–Sakurada relation.
Background.
Learning about morphological and biological features of pollen is very important to make correct estimations of plant productivity and breeding efficiency.
Materials and methods
. The ...viability of black currant pollen was analyzed in 2019 at the Laboratory for Long-Term Storage of Plant Genetic Resources, N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). Eleven black currant cultivars of various ecogeographic and genetic origin maintained at Pushkin and Pavlovsk Laboratories of VIR served as the material for the research. Pollen viability was tested on an artificial medium with 10% sucrose and 0.8% agar. Morphological studies were carried out using light and confocal laser scanning microscopy at the Palynology Laboratory and the Core Centrum of Cell and Molecular Technologies in Plant Science housed by the Komarov Botanical Institute (BIN).
Results and conclusion
. The prevailing adverse weather conditions in 2019 produced a negative impact on the process of male generative structure formation. The level of pollen viability, depending on the cultivar, ranged from 17.98 to 58.60%. After exposure to liquid nitrogen (–196°C) for 6 months, the number of germinated pollen grains increased 1.1 to 3.2 times in all the studied cultivars, except one (‘Pozdnyaya poslevoennaya’, k-7652). A palynomorphological study revealed that reduced pollen viability in some cultivars (‘Krasnoyarskaya 1018’, k-7607; ‘Tsema’, k-25900; ‘Pozdnyaya poslevoennaya’, k-7652) was associated with morphological deviations in the sporoderm structure (small pollen grains, exine thickening and formation of verrucate mesoporium surfaces). A low positive correlation was observed between the level of pollen viability and the diameters of the pore (r = 0.43) and pollen grain (r = 0.27). An insignificant negative correlation was apparent between the level of viability and the exine thickness (r = –0.33).
Procedure of early detection of a gradual change in insulating materials properties (disorder) is developed on the basis of thermal conductivity degradation under the hostility exposure. In the ...procedure of Bayesian statement development for early detection of a gradual disorder beside the initial data in which the disorder is searching it is proposed to use the additional information from indicators indirectly proofing a possible disorder. The simulated results showed that the value of delay in the detection of gradual change beginning of thermal conductivity in various insulating materials is reduced by an average of 20% in comparison with the existing procedures. The worked out procedure is meant for implementation in information-measuring systems of materials properties and process characteristics control.
100 years after the birth of polymer science, it can be stated that viscometry of dilute polymer solutions is the most popular method among molecular hydrodynamics methods, the purpose of which is to ...obtain the molecular characteristics of individual polymer chains. The viscous flow of dilute aqueous solutions of polyelectrolytes–statistical copolymers of N-methyl-N-vinylacetamide and N-methyl-N-vinylamine hydrochloride was investigated in the range of ionic strengths from the minimum (10–6 M) to the maximum possible 6 M NaCl. Intrinsic viscosities were determined as ∂lnηr/∂c at c → 0. The obtained generalized dependence of the intrinsic viscosity on the ionic strength of the solution in a double logarithmic scale is sigmoidal. The intrinsic viscosity values change insignificantly in the range 10–6–10–4 M. The nature of the change in the hydrodynamic volume of charged macromolecules in the entire range of ionic strengths of solutions is discussed in comparison with the theory of single polyelectrolyte macromolecule in the salt solution developed by Vasilevskaya et al., 26.
An algorithm for compensating image distortions under the influence of the surface deformation of the background screen when using the shadow background method. The efficiency of the algorithm is ...confirmed. We experimentally determined the optimal marker to be used for searching on the image. We examined the capabilities of the algorithm in compensating for the shift and rotation of the surface of the background screen with an mean square deviation of not more than 0.43 pixels, determined by cross-correlation processing.
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