902 research outputs found
Petro fabric characteristics of olivine from xenoliths, peridotites, and basalts (from Canary Islands, Kuznetsk Alatau and Yoko-Dovyren Massif)
This paper presents results of study of petro fabric specific characteristics of olivine from xenoliths, peridotites, and basalts (from Canary Islands, Kuznetsk Alatau and Yoko-Dovyren Massif
Sedimentary deposits and petrography of the basalts of the island of Tenerife of the Canary archipelago (Spain)
The article is devoted to the study of sedimentary deposits on the slopes of the Teide volcano and petrography of the volcanic rocks of the island of Tenerife of the Canary archipelago (Spain). A description of the sediments, which are presented on the island's territory, and an analysis of the features of the material composition of rocks are given
Application of hydrogenation to low-temperature cleaning of the Si(001) surface in the processes of molecular-beam epitaxy: Investigation by STM, RHEED and HRTEM
Structural properties of the clean Si(001) surface obtained as a result of
low-temperature (470--650C) pre-growth annealings of silicon wafers in a
molecular-beam epitaxy chamber have been investigated. To decrease the cleaning
temperature, a silicon surface was hydrogenated in the process of a preliminary
chemical treatment in HF and NH_4F aqueous solutions. It has been shown that
smooth surfaces composed by wide terraces separated by monoatomic steps can be
obtained by dehydrogenation at the temperatures > 600C, whereas clean surfaces
obtained at the temperatures < 600C are rough. It has been found that there
exists a dependence of structural properties of clean surfaces on the
temperature of hydrogen thermal desorption and the process of the preliminary
chemical treatment. The frequency of detachment/attachment of Si dimers from/to
the steps and effect of the Ehrlich-Schwoebel barrier on ad-dimer migration
across steps have been found to be the most probable factors determining a
degree of the resultant surface roughness.Comment: 8 pages, 8 figures; version accepted to J. Appl. Phy
Experience of universities in practice-oriented training personnel for high-tech enterprises
Different options have been considered of work-based learning (WBL) in Russian and foreign universities. Special attention is given to the variant of PBL - project learning (PL) on training bachelors. Basic concepts and principles have been discussed dealing with the organization of PL developed by Aalborg University - one of the founders of this teaching technique. Тhe advisability is shown of organizing special courses of introduction to project learning in the first two semesters.peer-reviewe
Analysis of the problems of formation of calligraphic skills in primary school pupils
The article presents the results of a study of calligraphic writing skills in primary school pupils of the general education school and analyzes problems with the acquisition of these skills.В статье представлены результаты исследования каллиграфического навыка письма у обучающихся начальных классов общеобразовательной школы, проведен анализ трудностей овладения данным навыком
Impact of High-Temperature, High-Pressure Synthesis Conditions on the Formation of the Grain Structure and Strength Properties of Intermetallic Ni[3]Al
The impact of the preliminary load on 3Ni+Al powder mixture and the impact of the duration of the delay in application of compacting pressure to synthesis product under the conditions of continuous heating of the mixture up to its self-ignition on the grain size and strength properties of the synthesized Ni[3]Al intermetallide material have been studied. The grain structure of the intermetallide synthesized under pressure was studied by means of metallography, transmission electron microscopy and EBSD analysis, with the dependence of ultimate tensile strength on the grain size in the synthesized intermetallide having been investigated at room temperature and at temperatures up to 1000°С. It is shown that an increase in the pressure preliminarily applied to the initial mixture compact results in reduced grain size of the final intermetallide, whereas an increase in pre-compaction time makes the grain size increased. A decrease in the grain size increases the ultimate tensile strength of the intermetallide. The maximum value of the ultimate tensile strength in the observed anomalous temperature dependence of this strength exhibits a shift by 200°С toward higher temperatures, and the ultimate strength of the synthesized intermetallide at 1000°С increases roughly two-fold
Regulation of flavonoid biosynthesis in representatives of the tribe Phaseoleae DC.
Flavonoids play a crucial role in plant metabolism. Many of them have antioxidant activity, and they are also pigments that render a variety of colors to plant tissues. Foods rich in flavonoid compounds are considered as functional components of a healthy diet. Currently, there is an increased interest in studying genetic mechanisms underlying the coloration of plants. Flavonoid biosynthesis pathways are controlled by two groups of genes. Structural genes encode enzymes, while regulatory genes are responsible for transcription factors that activate the expression of structural genes. Transcription factors that belong to R2R3-Myb, bHLH-Myc and WDR families form the ternary MBW complex, which is involved in regulating the expression of structural genes of flavonoid biosynthesis. The mechanisms of regulation of the anthocyanins and proanthocyanidin biosynthesis by the MBW complex are described in detail for the model plant Arabidopsis thaliana L. This review summarizes data on the regulation of phenolic pigment biosynthesis and the features of phenolic pigment accumulation in plant tissues in the main representatives of the Phaseoleae tribe: soybean Glycine max (L.) Merr., common bean Phaseolus vulgaris L., adzuki bean Vigna angularis (Willd.) Ohwi & Ohashi, and cowpea V. unguiculata (L.) Walp. The species discussed in this review are the most important food legumes in many countries of the world and they comprise the staple food in diets of millions of people. Identification and characterization of the genes controlling the flavonoid biosynthesis pathways are necessary for successful breeding of modern varieties with an increased dietary value. Identification of the flavonoid accumulation patterns is essential for solving the problem of broadening the diversity of plant products
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