602 research outputs found
Mass and momentum transfer by solitary internal waves in a shelf zone
The evolution of large amplitude internal waves propagating towards the shore and more specifically the run up phase over the "swash" zone is considered. The mathematical model describing the generation, interaction, and decaying of solitary internal waves of the second mode in the interlayer is proposed. The exact solution specifying the shape of solitary waves symmetric with respect to the unperturbed interface is constructed. It is shown that, taking into account the friction on interfaces in the mathematical model, it is possible to describe adequately the change in the phase and amplitude characteristics of two solitary waves moving towards each other before and after their interaction. It is demonstrated that propagation of large amplitude solitary internal waves of depression over a shelf could be simulated in laboratory experiments by internal symmetric solitary waves of the second mode
Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of
Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It’s highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more
Influence of ionic balance on the process of microcrystal AgBr (111) maturing
The research of the effect of photosensitivity level increase found in the process of maturing microcrystals AgBr with octahedron facets (111) without addition of sulphur containing additives (natural maturing) is carried out. It is stated that formation of sensitivity centres occurs during modification of AgBr (111) microcrystal form owing to difference of chemical potentials of microcrystal sides. Thus, the direct proofs of silver nature of sensitivity centres at maturing of AgBr (111) microcrystals in the conditions involved are obtained. The reasons of absence of natural maturing for AgBr microcrystals of a cubic facet (100) and flat AgBr (Т-МC) microcrystals are discussed
The spatial distribution the thickness of polymer powder coatings for ultrasonic sensors
© Published under licence by IOP Publishing Ltd. Objects of research are coatings and technology of their applying to the piezoelectric elements for ultrasound. Results of studies the distribution coating thickness according to different modes of coating process are presented. Experimentally confirmed the simulation results of the movement gas suspension on the electrostatic field in the electrode system "needle - plane"
Quantitative and qualitative analysis of sunflower pollen (<i>Helianthus</i> L.) and it’s use in breeding work
Background. In breeding work, it is necessary to take into account such an important feature as male sterility of the hybrids obtained. If a plant has visually visible anthers and pollen, the quality of the pollen grains themselves may be low. It is necessary to carry out not only a visual analysis, but also a cytological study of pollen in order to properly assess the reproductive potential of plants.Materials and methods. Wild species, some cultivars, lines and hybrids of sunflower from the collection of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources were taken as objects of research. The plants were grown on the fields of Kuban Experiment Station. Pollen was collected from preinsulated inflorescences, fixed in FAA solution and stained with acetocarmine. The ratio of fertile pollen grains to the total number of pollen grains (in %) was calculated, the diameter of the pollen grains was measured, and variability curves were drawn.Results. Mature pollen grains in sunflower are rounded, tricolpate-poral, threecelled; the average pollen diameter in cultivated sunflower is 28–32 μm; in wild species, the range is from 20– 22 μm to 32–34 μm. All accessions were divided into three groups. Fertile: high level of fertility (75–99%) and low morphological heterogeneity of pollen; the variation curve for the average diameter was characterized by one distinct peak. Most of the studied accessions were included here: cultivars, most of the lines and some of the wild species. Semi-fertile: the number of well-stained pollen grains is below 75%; there are differences in the degree of staining and size of the pollen; the variation curve had additional peaks. This group included some of the lines, hybrids and wild species. The greatest morphological heterogeneity was observed in the group of perennial interspecific hybrids. Sterile: pollen grains were absent or were observed very sporadically.Conclusion. To assess the fertility of plants, it is important not only to determine the degree of staining in pollen grains, but also to rank them by diameter and construct variation curves to reveal morphological heterogeneity of pollen
Protective matching polymer powder coating of piezoelectric element
Objects of research are coatings and technology of their applying to the piezoelectric elements for ultrasound. Acoustic impedance and thicknesses of matching layers for medical ultrasound transducers have been defined. In this paper performance characteristics of coating systems with predetermined properties have been selected. The conditions for selection of polymer powder paint for quarter wave matching layer have been determined. Conditions of forming polymer powder coatings have been proposed. © Published under licence by IOP Publishing Ltd
Phase equilibria, crystal structure and oxygen nonstoichiometry of the complex oxides in Sm – (Sr, Ba) – (Co, Fe) – O systems
Received: 18.01.2018. Accepted: 14.02.2018. Published: 10.05.2018.Present paper contains available information on the phase equilibria in the Sm – (Sr, Ba) – (Co, Fe) – O systems, including the synthesis routes used, crystal structure, which is often depended on oxygen nonstoichiometry, the data on thermodynamic stability of complex oxides, the obtained results on the homogeneity ranges of solid solutions, formed in the systems, and graphical presentation of phase relations in a form of phase diagrams
O desenvolvimento de um componente motivacional e de valor da criatividade dos estudantes do primeiro ano
The article is devoted to the study and identification of ways to increase the development of the motivational and value component of the creativity of first-year students. The authors actualize the problem of activating professionally-oriented creative activity of students in the modern educational process, specify the concept of professional creativity. In the study, the authors identify and theoretically substantiate the ways of developing the motivational and value component of the creativity of first-year students in the educational space of the university on the example of the Belgorod Institute of Arts and Culture, offering an experimental model of the gradual development of professional creativity. A practical study of the development of the motivational and value component of the creativity of first-year students, which formed the basis of the general theory of professional creativity, was conducted.El artículo está dedicado al estudio e identificación de formas de incrementar el desarrollo del componente motivacional y valorativo de la creatividad de los estudiantes de primer año. Los autores actualizan el problema de activar la actividad creativa orientada profesionalmente de los estudiantes en el proceso educativo moderno, especifican el concepto de creatividad profesional. En el estudio, los autores identifican y fundamentan teóricamente las formas de desarrollar el componente motivacional y de valor de la creatividad de los estudiantes de primer año en el espacio educativo de la universidad en el ejemplo del Instituto Belgorod de Artes y Cultura, ofreciendo un modelo experimental. del desarrollo gradual de la creatividad profesional. Se realizó un estudio práctico del desarrollo del componente motivacional y de valor de la creatividad de los estudiantes de primer año, que formó la base de la teoría general de la creatividad profesional.O artigo dedica-se ao estudo e identificação de formas de aumentar o desenvolvimento do componente motivacional e valorativo da criatividade dos alunos do primeiro ano. Os autores atualizam o problema de ativar a atividade criativa profissionalmente orientada dos alunos no processo educacional moderno, especificando o conceito de criatividade profissional. No estudo, os autores identificam e fundamentam teoricamente as formas de desenvolver o componente motivacional e valorativo da criatividade dos alunos do primeiro ano no espaço educacional da universidade a exemplo do Instituto Belgorod de Artes e Cultura, oferecendo um modelo experimental do desenvolvimento gradual da criatividade profissional. Foi realizado um estudo prático do desenvolvimento do componente motivacional e valorativo da criatividade dos alunos do primeiro ano, que constituiu a base da teoria geral da criatividade profissional
Biological peculiarities and cultivation of groundnut (a review)
Peanut is one of the most important crops in the Fabaceae Lindl. (Leguminosae L.) family. South America is considered to be the homeland of peanut, but now this crop is cultivated in America, Africa, Australia, Europe and Asia. The modern phylogenetic system of the genus Arachis L. includes 79 wild species and one cultivated species of common peanut (A. hypogaea L.). Diploid species contain 2n = 20 chromosomes of the A, B or D genome, tetraploids have A and B genomes. The А and В genomes are sequenced. Special biological features of all peanut varieties are the presence of chasmogamous and cleistogamous flowers and the development of pods only underground (geocarpy). Along with high requirements for improving the quality of oil and food products, much attention is paid to their safety: resistance to aflatoxin contamination and mitigation of allergenicity. Peanut cultivars vary in plant habit, shape and color of pods and seeds. Their growing season in Africa, Latin America and Asia is from 160 to 200 days, so early-ripening forms need to be selected for the south of the Russian Federation. Breeders from the Pustovoit Institute of Oil Crops (VNIIMK) have developed peanut cultivars with a yield of 2.0–3.3 t/ha and growing season duration of 115–120 days, adaptable to the environments of Krasnodar Territory. At present, there is no large-scale peanut production in Russia, nor any breeding efforts are underway. As for the world, along with conventional breeding practices (individual selection, intra- and interspecies crosses, etc.), peanut is widely involved in genomic studies. A number of cultivars highly resistant to pests, diseases and drought have been released. Over 15,000 peanut accessions are preserved in the world’s gene banks, including 1823 accessions in the collection of the Vavilov Institute (VIR). Utilization of the worldwide genetic resources of peanut and use of modern research technologies will contribute to the revival of peanut cultivation in Russia
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