Shishulin A.V.1, Potapov A.A., Shishulina A.V.
ON THE TRANSITION BETWEEN FERROMAGNETIC AND PARAMAGNETIC STATES IN MESOPOROUS MATERIALS WITH FRACTAL MORPHOLOGY.
In this paper, we have shown how the presence of pores and pore morphology influence on magnetic phase transition temperatures in mesoporous ferromagnetic materials. Model calculations have demonstrated the possibility to obtain macroscopic mesoporous samples with notably reduced Curie temperatures which is also further depressed in the case the pore morphology is more complicated. The results have been obtained on the basis of the experimentally verified correlation between the Curie temperature and cohesive energy of the material and illustrated using the examples of pure mesoporous iron, nickel and cobalt while pore morphology has been determined by the methods of fractal geometry. Several practical applications of mesoporous materials with tuned values of the Curie temperature have also been discussed in the final section.
Ibrayev N.Kh., Dzhanabekova R.Kh., Amanzholova G.S.
SPECTRAL AND LUMINESCENT PROPERTIES OF CARBON QUANTUM DOTS FUNCTIONALIZED WITH N- AND S-CONTAINING GROUPS.
In the presented work, carbon quantum dots were obtained by microwave synthesis based on citric acid and L-cysteine. The resulting particles were characterized by electron and probe microscopy, dynamic light scattering and Fourier transform infrared spectroscopy. The spectral and luminescent properties were investigated for the initial solution of carbon quantum dots, as well as solutions obtained as a result of dialysis of the synthesized product. It is shown that all samples exhibit the same optical properties. At the same time, the measurement of quantum yields showed that carbon dots that have passed through the dialysis membrane have the best fluorescent ability.
Surzhikov A.P., Маlyshev A.V., Lysenko Е.N., Sheveleva E.A., Stary O., Ghyngazov A.S.
ELECTROMIGRATION IN LITHIUM-TITANIUM FERRITE CERAMICS SINTERED IN RADIATION-THERMAL MODE
The study investigates electro-migration in Li–Ti ferrite ceramic samples sintered in radiation-thermal mode. To reveal radiation effects, similar measurements are performed for samples sintered in thermal mode. The effect of the state of grain boundaries and the presence of a low-melting additive on electrical properties of sintered ferrites is studied. It is found that structural rearrangement during radiation-thermal sintering occurs in early sintering stages, including the heating period. Study demonstrates that such behavior associated with radiation-induced intensification of the liquid phase spreading over the array of powder grains. In addition, it was shown that structural transformation may be caused by stimulation of intergranular slippage.
DETERMINATION OF CRITICAL DOSES OF RADIATION DAMAGE TO ALN CERAMIC UNDER IRRADIATION OF HELIUM AND HYDROGEN IONS
The work is devoted to the study of the radiation damage kinetics to heat-conducting, insulating and mechanical properties in polycrystalline ceramics based on aluminum nitride under irradiation of helium and hydrogen ions, as well as the determination of critical doses that cause maximum irreversible consequences. The choice of ions for irradiation is due to the ability to simulate the radiation damage processes during the accumulation of helium and hydrogen ions in the structure of the near-surface layer with the subsequent formation of gas-filled bubbles. During the studies carried out, it was found that at doses of irradiation with helium ions above 1х1017 ion/cm2, there is a sharp deterioration in thermal conductivity and a decrease in ceramic resistance, which is associated with the onset of the formation of helium bubbles and partial embrittlement of the near-surface layer. However, an increase in the radiation dose above 5×1017 ion/cm2 does not lead to significant changes in thermal conductivity and insulation characteristics, which indicates the effect of radiation damage accumulation and a decrease in the ceramic degradation rate. In contrast to irradiation with helium ions, irradiation with hydrogen ions to doses higher than 1-3х1017 ion/cm2 does not lead to significant changes in the thermal insulation characteristics, which indicates the ceramic resistance to hydrogen absorption processes.
Ibrayev N.Kh., Afanasyev D.A., Omarova G.S.
FEATURES OF STIMULATED EMISSION OF A MEROCYANINE DYE IN THE PORES OF ANODIZED ALUMINUM
The results of the study of the spectral-luminescent properties and the generation of stimulated emission of merocyanine dye molecules in a porous aluminum oxide films are presented. The addition of silver nanoparticles to the porous aluminum oxide films leads to an increase in the absorption cross section and an increase in the quantum yield of dye fluorescence in the alumina films. However, in the alumina films with silver nanoparticles, the generation of stimulated emission of dye molecules was not detected. We also studied the effect of polymethyl methacrylate polymer deposited on the surface of the alumina films with a dye on the spectral-luminescent properties and generation of stimulated emission of this dye. An increase in the optical density in the absorption band of the dye and an increase in the fluorescence intensity in samples with a deposited polymethyl methacrylate film are observed. The generation threshold of polymethine dye is reduced by a factor of 40 in the porous aluminum oxide sample with polymethyl methacrylate.
Rakhadilov B.K., Akatan K., Maulet M., Kabdrakhmanova S.K., Magazov N.M.
ИССЛЕДОВАНИЕ ВЛИЯНИЯ ЭЛЕКТРОННОГО ПУЧКА НА ФИЗИКО-ХИМИЧЕСКИЕ СВОЙСТВА ПОЛИАМИДА 6.
In this research work has been studied the effect of electron irradiation on the properties and structure of PA6 polyamide. The treatment was carried out with an industrial pulse accelerator in air with an irradiation dose in the range of 100-400 kGy. The processed polymer was also studied by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray phase analysis and differential scanning calorimetry. According to the results of the study was known that electron beam treatment affects the crystal structure of polyamide-PA6, reducing its size. Also, it was found that the radiation dose of 200 kGy is optimal for preserving the crystal structure in comparison with 100, 300 and 400 kGy.
Zeinidenov А.К., Abisheva А.К., Ilyassov B.R., Aimukhanov А.К., Abilmazhinov S.E.
INFLUENCE OF STRUCTURAL FEATURES OF ZNO FILMS ON OPTICAL AND PHOTOELECTRIC CHARACTERISTICS OF INVERTED POLYMER SOLAR ELEMENTS
In this work we investigated the effect of preliminary annealing of zinc acetate solution films on the morphology, structure, optical properties of the formed ZnO films and also on the photovoltaic properties of polymer solar cells based on the obtained ZnO films. It was found that the pre-annealing temperature significantly affects the morphology and structure of the obtained ZnO films. At pre-annealing temperatures below 200 oC the films have a strongly relief morphology (wrinkled morphology), while at pre-annealing temperatures above 200oC the surface morphology of the films is smooth. The relief of ZnO films affects the photocurrent density of solar cells. Cells based on ZnO films with wrinkled morphology showed a higher photocurrent compared to smooth morphology, which is due to strong light scattering and, as a result, the optical path of light in the photoactive layer is increased due to multiple reflection of light in the wrinkled structure of ZnO. In addition, with increasing pre-annealing temperature, the photovoltage of solar cells and the rate of recombination of charge carriers increases, but the diffusion coefficient of charge carriers decreases, which indicates an increase in the density of defects in the crystal lattice of ZnO. Thus, it has been shown that smooth or highly relief thin ZnO films with controlled properties can be obtained from a zinc acetate solution.
Moiseeva K.M., Krainov A.Yu., Krainov D.A.
COMBUSTION OF ALUMINUM POWDER-AIR SUSPENSION IN A SWIRL FLOW
The article is devoted to the numerical solution of the problem of the combustion of powder metal fuel in a combustion chamber with swirling flow. A physico-mathematical model of the flow of an air suspension of aluminum powder in a swirling flow in a cylindrical combustion chamber with a sudden expansion is presented. The physical and mathematical formulation of the problem is based on the approaches of the mechanics of two-phase reacting media. The solution was carried out using the arbitrary discontinuity decay method. The results of a numerical parametric study of the features of the combustion of an air suspension of aluminum powder depending on its composition, the axial flow rate of the mixture at the entrance to the combustion chamber, and the value of the swirl speed are shown.
Manatbayev R.K., Kalassov N.B., Amankeldi L.B.
NUMERICAL INVESTIGATION OF THE OCCURRENCE OF A CONCENTRATION-POLARIZATION LAYER
This work describes the appearance of a concentration polarizing boundary layer on the membrane surface during the separation of the H2/CO2 gas mixture. Concentration polarization occurs when the rejection solution accumulates near the surface of the membrane, forming a boundary layer. The inclusion of concentration polarization effects in the processing of porous walls creates additional difficulties. The boundary layer formed by concentration polarization can be considered as a type of a second porous wall with a lower permeability than the membrane. The main difficulty in modeling this situation is to determine the appropriate boundary conditions for the concentration on the wall, since the concentrations on the wall will constantly change, and the wall geometry itself may change over time due to particle deposition. To account for this effect, a numerical approach was developed, which is discussed in this work.
Mekhtiyev A.D.1,2, Sarsikeyev Y.Z. 1, Yugay V.V.3, Neshina Y.G.3, Alkina A.D.
THERMOACOUSTIC ENGINE AS A LOW-POWER COGENERATION ENERGY SOURCE FOR AUTONOMOUS CONSUMER POWER SUPPLY
The article deals with the issue of using a thermoacoustic engine as a low-power cogeneration source of energy for autonomous consumer power supply capable of operating on various types of fuel and wastes subject to combustion. The analysis of the world achievements in this field of energy has been carried out. A number of advantages make it very promising for developing energy sources capable of complex production of electrical and thermal energy with a greater efficiency than that of present day thermal power plants. The proposed scheme of a thermal power plant is based on the principle of a Stirling engine, but it uses the most efficient and promising thermoacoustic converter of heat into mechanical vibrations, which are then converted into electric current. The article contains a mathematical apparatus that explains the basic principles of the developed thermoacoustic engine. To determine the main parameters of the thermoacoustic engine, the methods of computer modeling in the DeltaEC environment have been used. A layout diagram of the laboratory sample of a thermal power plant has been proposed and the description of its design has been given. It has been proposed to use dry saturated steam as the working fluid, which makes it possible to increase the generated power of the thermoacoustic engine.
Kubich V.I., Cherneta O.G., Yurov V.M.
INFLUENCE OF BORINATION, BORON CEMENTATION OF STEEL 45 AND VISCOSITY OF A LUBRICANT ON THE PARAMETERS OF ADHESION BOND IN THE STEEL 45 – 40X SYSTEM.
In the work, the regularities of changes in the shear strength of the adhesive bond τ and the piezoelectric coefficient β in the metal systems “steel 45 – 40X”, “steel 45+В-40Х”, “steel 45+ВС-40Х” were obtained during physical modeling of the materials I-20A, Wolf 10W-40, TAD-17i, Litol-24 with distinctive dynamic viscosities using the additional equipment of the SMTs-2 friction machine. It has been established that a twofold increase in the shear rate causes a decrease in the piezoelectric coefficient in the “steel 45+VS – 40X” system by a factor of 1.2-1.6 for Wolf 10W-40, TAD-17i, Litol-24 lubricants and its relative similarity independent of dynamic viscosity. At the same time, a twofold increase in the shear rate in the “steel 45+B-40X” system also causes a decrease in the piezoelectric coefficient by a factor of 1.16-1.38 for all tested lubricants and its alignments, as in the “steel 45+VS” system, does not observed. It was found that the clearly expressed regularity of the effect of the equivalent dynamic viscosity on the strength of the adhesive bond at p = 0 MPa is not revealed, and the nature of the manifestation is predetermined by a possible change in the mechanism of intermolecular interaction, which depends on the structure of the molecules of lubricants. It was determined that the piezoelectric coefficient naturally decreases with an increase in dynamic viscosity in the entire considered range of normal pressures.
Amelkovich Yu.A., Nazarenko O.B., Smirnova I.N., Zadorozhnaya T.A.
COMPARATIVE STUDY OF THE EFFECT OF FLAME RETARDANTS ON THE IGNITION TEMPERATURE OF EPOXY COMPOSITES.
The disadvantage of polymeric materials, including epoxy resins, is their increased fire hazard. Reducing the flammability of polymeric materials is a serious problem that needs to be addressed. One of the ways to reduce the flammability of polymers is the introduction of special additives into the polymer matrix with flame retarding properties, which leads to a change in the nature of the processes occurring during the combustion of the polymer, or to blocking the combustion process with non-combustible or inhibiting substances. In this work, aluminum trihydroxide, melamine polyphosphate, and melamine poly(magnesium phosphate) were used as flame retardants to enhance the flame-resistant properties of epoxy resin. The filler loading in the epoxy composites was 10 wt. %. The experimental studies have been carried out to determine the ignition temperature of the produced epoxy composites. The data obtained were compared with the ignition temperature of a control sample of epoxy resin without filler. The results indicated that the incorporation of all the flame retardants studied resulted in an increase in the ignition temperature. The ignition temperature of the samples filled with melamine polyphosphate and melamine poly(magnesium phosphate) increased by 28 and 11 °C, respectively. However, the best result was obtained for a sample filled with aluminum trihydroxide: the ignition temperature of this sample was 40 °C higher than that of the unfilled epoxy resin.
Zhanabaev Z.Zh., Ussipov N.M.*, Khokhlov S.A.
SCALE-INVARIANT AND WAVE NATURE OF THE HUBBLE PARAMETER.
The value of the global Hubble parameter corresponding to astrophysical observations was determined theoretically without using ʌСDM models. A nonlinear fractal model of the connection between the distance to the observed galaxy and its coordinate is proposed. Distance is defined as a fractal measure, the measurement scale of which, in contrast to the known fractal models, corresponds to the deviation of the desired measure itself from its fixed value (radius of zero gravity), relative to which the scale invariance is assumed. We used the dimension of our proposed specific anisotropic fractal, which simulates the increase in the distance to the observation point. It is shown that this dimension is also the maximum dimension of the strange attractor of the phase portrait of the equation of gravitational waves and sets of galaxies from different catalogs.
Vitkovskaya I.S., Batyrbayeva M.Zh.
SATELLITE DATA PROCESSING ALGORITHM IN THE PROCESS OF FORMATION OF THE TIME SERIES OF VEGETATION INDEXES.
The diverse spectral indexes computed from the satellite images are used extensively in the world practice of remote sensing of the Earth from space. This approach proved its validity for the satellite monitoring of the underlying terrain, detection of ongoing changes and trends of their dynamic patters. Accumulated prodigious amount of satellite data, the state-of-the-art methods of thematic interpretation gave rise to creation of services providing free access to both images and to image processing results. Notwithstanding the foregoing, in the furtherance of the local and regional scale it turns out that usage of the end products of thematic processing of space information supplied by the known available services was not efficient on all occasions. Consequently, we may need to generate our own archives of the long-term series of satellite indexes. The volume of files containing the digital index matrices computed based on the MODIS satellite low resolution data subject to the complete coverage of the territory of Kazakhstan surpasses 4 Gb. This often results in the delayed computations, and on frequent occasions in infeasibility of computation of a full matrix when the medium specs computers are employed. This article is focused on the satellite data processing algorithm in the process of formation of the time series of vegetation indexes. As a consequence, the multi-year archive of vegetation indexes (over a period of 2001-2020), which provided a basis for trend analysis of the underlying terrain, determination of their future trends and forecasting of their changes was created within the territory of the Republic.
Kambarova Zh.T.1*, Saulebekov A.O., Kopbalina K.B., Tussupbekova A.K., Saulebekova D.A.
ABOUT THE POSSIBILITY OF CREATING AN EFFICIENT ENERGY ANALYZER OF CHARGED PARTICLE BEAMS BASED ON AXIALLY-SYMMETRIC OCTUPOLE-CYLINDRICAL FIELD.
One of the problems in creating systems for energy analysis of charged particles beams is to determine the deflecting field and calculation the shape of the deflecting electrodes. This article is devoted to the study of the possibility of creating an effective energy analyzer of charged particle beams based on multipole electrode systems. A previously unstudied type of a multipole-cylindrical field – an electrostatic axially-symmetrical octupole-cylindrical field was chosen as the deflecting field. The field is formed by using the superposition of an electrostatic cylindrical field and a circular octupole of various contributions. The family of the equipotentials of cylindrical octupoles with planes of symmetry and antisymmetry is calculated. The calculation and analysis of equipotential portraits of the electrostatic axially-symmetric octupole-cylindrical fields with different weight contributions of the cylindrical field and circular octupole are carried out.