Investigation of the effect of crystal defects on nonpolar a-GaN films grown by metalorganic chemical vapor deposition on r-sapphire substrates is presented. Samples were grown at different ...temperatures and the same V/III ratio. High-temperature nucleation in combination with low-temperature GaN buffer layer growth was used to achieve a smooth morphology and “mirror” surface. The macrostructures of the defects were investigated using a scanning electron microscope. Defect concentration via dislocation type correlation was analyzed by diffractometry investigation. Structural quality was investigated via x-ray diffraction. The correlation between the densities of mixed threading dislocations and V-defects was determined. It was detected that the origin of V-defects on the a-plane and c-plane was the same despite having completely different geometries and structures. We also investigated the dependence of V-defect density on a-GaN film growth temperature at a constant hydrogen flow through a triethylgallium source, and we also investigated how the V/III ratio influenced the V-defect structure. Optimum growth parameters for defect concentration reduction were determined.
The first test results of synthetic diamond grown by CVD for a fast neutron detector are reported. The detector has size - 5 × 5 mm. The Pt contacts formed to both substrate sides were 4×4 mm. The ...detector was irradiated by 14 MeV neutrons from a D-T generator. The obtained registration efficiency was 0.63 · 10−2 pulses/neutron.
The results of the research on the functional properties of waxy wheat flour, obtained from the spring waxy wheat grain of the Biskvitna variety, adapted for agro-climatic conditions of the Kharkiv ...region, in comparison with white wheat flour, are presented. It is found that waxy wheat flour contains 16.8% less raw gluten than the reference sample, the gluten is 18.8% less elastic and 21.4% more stretchy, has a light gray color and can be attributed to the II group of quality. Waxy wheat flour has a 1.8 times higher water-holding capacity, its starch begins to gelatinize at a lower temperature, while the maximum viscosity of the waxy wheat flour starch paste is almost 1.6 times higher than that of the reference sample. It is established that falling number of waxy wheat flour is only 68 s that more than 5 times lower than that one of wheat flour. The model dough system prepared from the waxy wheat flour has a 6.9% better lifting power in comparison to the system prepared from the wheat flour. Baking tests for sponge cakes, biscuits, fruitcakes and muffins with the substitution 25.0 to 75.0% of white flour to waxy wheat flour was performed. With an increasing of the dosage of waxy wheat flour a tendency of the increasing of the dough stickiness in all samples tested was observed. The baked goods tested were distinguished by good quality indicators, although in fruitcakes and muffins with a dosage of waxy wheat flour of more than 50.0%, the formation of large gas cells unevenly distributed in the crumb was noticed. Addition of 25.0% of waxy wheat flour causes an increase of the specific volume and porosity of sponge cakes by 11.1 and 9.3% respectively. With a further increase in the dosage of waxy wheat flour, the specific volume and porosity of the samples tested are verging to the reference sample. All samples of fruitcakes and muffins were not differ significantly in terms of specific volume and porosity. According to the results of the research conducted, it is suggested to use waxy wheat flour, obtained from the grain of Biskvitna variety, for the production of sponge cakes and biscuits in an amount of up to 75.0%, for fruitcakes and muffins - in an amount of up to 25.0% instead of wheat flour.
By the original method, using the sequential high-purity Mn and Sb metals evaporation, followed by annealing under high vacuum conditions, MnSb semiconductor films were synthesized. It is shown that ...the high chemical activity of nanostructured Mn and Sb films significantly reduces the manganese antimonide evaporation temperature. Films are p- type and have a high charge carriers mobility.
Abstract
Current investigation is focused on In
x
Ga
1-x
P and In
x
Al
1-x
P epitaxial layers growth. Multicomponent nanoheterostructures are the main materials for a contemporary triple-cascade ...solar cell, and for perspective photovoltaic devices. The optimal In
x
Ga
1-x
P and In
x
Al
1-x
P growth process characteristics are determined. In
x
Ga
1-x
P epitaxial layers (with In & Ga varied on Ge), and In
x
Al
1-x
P layers (with Al & In varied on Ge and GaAs) are investigated. During investigation X-ray diffractometry was used. Based on results of X-ray diffractometry the lattice parameter and In / Ga / Al ratio in the structure were detected. Solid phase versus the gas phase composition correlation was found based on the lattice parameters. It is determined that diffraction X-ray peaks broadening can be used as a parameter for the heterostructure perfection analyze. For the In
x
Ga
1-x
P solid solution (X = 45–53 %) and for In
x
Al
1-x
P solid solution (X = 46-51 %) a high quality of the single-crystal structure and a slight diffraction X-ray peaks broadening are detected.
The influence of the charge treatment by ultrahigh dilution (UHD) technology on oxide single crystals grown by the Czochralski technique was studied for monoclinic MgMoO4 crystals doped by 1 at. % of ...Nd3+ ions. The series of 10 Nd:MgMoO4 crystals was grown from the charges that were subjected to UHD treatment, as well as from the charges treated with two types of control or with no special treatment at all. The grown crystals were studied by X-ray powder diffraction analysis, inductively coupled plasma atomic emission spectroscopy, mass-spectrometry, optical absorption, emission spectroscopy and luminescence kinetic analysis. We found that: (i) wetting of MgO + MoO3 mixture by a water-ethanol solution before calcining leads to some enrichment of the mixture with MoO3, whereas the wetting of the charge after the calcining leads to some enrichment of it with MgO; (ii) congruent melting composition of MgMoO4 crystal is in the field of some MoO3 excess; (iii) the solid-phase solubility of the excess MoO3 in MgMoO4 probably does not depend on temperature, whereas the solid-phase solubility of the excess MgO in MgMoO4 crystal depends on temperature. We suggest that the corresponding solidus line passes through the range of retrograde solubility; (iv) the crystals grown within this range are characterized by the enhanced Nd3+ segregation coefficient between the crystal and the melt (approximately 0.006 versus 0.004); (v) unit cell parameters of MgMoO4 crystal with the excess of MoO3 are larger than those of the crystal of the stoichiometric composition and of the crystal with the excess of MgO; (vi) the shapes of the optical absorption and luminescence spectra of Nd:MgMoO4 crystal do not depend on the charge treatment; (vii) luminescence decay kinetics are single-exponential for all the studied crystals, the luminescence decay time being different for the crystals grown from the charges that underwent different types of treatment; (viii) the luminescence intensity of Nd:MgMoO4 crystal grown from the charge that underwent UHD treatment before calcining (solid-phase synthesis) is reduced by an order of magnitude in comparison with the other studied crystals.
The article presents the results of studying the technological properties of emmer flour obtained from the grain of the variety Golikovska, in comparison with commercial patent wheat flour. It has ...been found that emmer flour contains 1.4 times as much crude gluten and 1.3 times as much dry gluten as wheat flour does. It has been shown that gluten of emmer flour is 1.2 times less strong and 1.3 times more elastic than gluten of wheat flour, and can be included in the 2nd group of quality. According to the results of farinographic tests, it has been established that the experimental emmer dough sample is formed 2 minutes earlier and is 3 times less stable than wheat dough. The results of the alveographic tests have shown that, compared to wheat dough, the tenacity of emmer dough is lower by 25.9%, the extensibility is higher by 26.3%, its alveogram configuration ratio is lower by 36.4%, and its baking strength is lower by 28.2%. It has been established that the starch of emmer flour starts being gelatinised (turning into paste) a little later and at a slightly higher temperature than wheat flour starch does. The maximum viscosity of wheat starch paste is by 58.3% higher than that of emmer starch paste. It has been established that the falling number of emmer flour is by 9.6% smaller in comparison with that of wheat flour. The dough-raising capacity of model yeast dough systems prepared from emmer flour is by 25.0% better than it is in model systems made from wheat flour. It has been found that in emmer yeast dough, fermentation processes are more intensive than in wheat yeast dough: at the end of fermentation, the emmer dough had by 13.3% higher titrated acidity and had formed by 12.5% more carbon dioxide. The volume of emmer dough was by 16.7% higher than that of wheat dough. The sensory evaluation of unleavened and yeasted puff pastries made from emmer flour has shown that they are not inferior in quality to baked products made from wheat flour, have a regular shape and a bright crust colour, and are large in volume.
The extremely rapid development of an information-aware society requires the effective regulation of the state policy in the field of combating cybercrime. The rapid development of technology creates ...new opportunities in the use of information space, but new opportunities entail new threats in this area. In order to prevent and develop an effective mechanism to repel existing and future threats in the field of cyberspace, it is necessary to study the purpose, tasks and principles of the state policy in the field of combating cybercrime.
The purpose of the article is to define the concept of the term of “politics”, in a broad sense, the concept of “state policy”, on the basis of scientific works of scholars, setting the tasks of the state policy in combating cybercrime.
The methodological basis of the study is modern general and special methods of scientific cognition, the use of which is determined by a systematic approach.
The author of the article considers the scientific works of foreign and domestic scholars who have studied the concept of politics and the concept of state policy in a broad sense. The author has formulated own vision of the terms of “state policy” and “state policy in the field of combating cybercrime”. The study found out that the purpose of state policy in the field of combating cybercrime is to create conditions for the safe operation of cyberspace and its effective use in the interests of individuals, society and the state. The list of tasks of the state policy in the field of counteraction to cybercrime is formulated. It was found out that the purpose and tasks of the state policy in the field of combating cybercrime determine the system of principles, which should be the basis for such a policy. The priority system of principles of the state policy in the field of combating cybercrime is highlighted. The publication will be useful for students, cadets, teachers, post-graduate students and doctoral students of higher education in the field of jurisprudence, as well as anyone interested in the state policy in the sphere of combating cybercrime.
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