The effect of different concentrations of aluminosilicate fly ash cenospheres, as well as silver-coated aluminosilicate fly ash cenospheres, on the structure and thermal properties of polymeric composites has been studied. In the scope of this work, composites based on styrene–butadiene–styrene triblock copolymer and aluminosilicate cenospheres with different ratios between components in the mixture have been studied. By using optical microscopy, it has been shown that aluminosilicate cenospheres introduced into the polymeric matrix through a solution are evenly distributed throughout the entire volume of the film, with no formation of any aggregates or agglomerates. Thermal analysis has shown that cenospheres provide an increase in the thermal resistance of composites. At the same time, the increase in the aforementioned thermal parameters is correlated to a great extent with the amount of filler. By using infrared spectroscopy, it has been shown that the IR spectra of the composites exhibit new signals corresponding to the stretching vibrations of SiO2 and metal oxides.

The use of industrial waste to develop new value-added materials and reduce their environmental impact is one of the most important tasks of science and industry, which can largely solve the problem of waste pollution. This work is aimed at studying the effect of different concentrations of fly ash aluminosilicate cenospheres on the structure and properties of elastomeric composites. In this work, using laboratory rollers, composite materials based on ethylene-propylene-diene rubber (EPDM-40) with different mass fractions of fly ash (10, 20 and 30 %) were obtained. Using the method of optical microscopy, the microstructure of mixtures of EPDM and aluminosilicate cenospheres was studied and it was shown that the filler content of more than 30% increases the content of larger cenosphere agglomerates in the structure, which indicates interfacial separation in mixtures, probably due to the fact that mechanical mixing on mixing equipment does not allow to achieve a uniform distribution of the filler throughout the elastomeric matrix. The IR spectra show the appearance of new absorption bands in the region. 1400 – 800 cm–1, corresponding to Si – O – Si stretching vibrations present in aluminosilicate cenospheres. According to the thermogravimetry data of the studied compositions, the introduction of aluminosilicate cenospheres contributed to a slight increase in the thermal stability of the tested composition with a cenosphere content of more than 30%. The influence of the concentration of aluminosilicate cenospheres on the resistance of composites to aggressive media was analyzed and it was found that the introduction of a cenosphere filler in an amount of 10 to 30 % in a mixture based on EPDM can increase the oil and petrol resistance of materials.

In this paper, we aim to formulate a new rubber material for the diaphragm of press vulcanizers, which are crucial in automotive tire production. Rubber mixtures used to produce diaphragms of vulcanizers, that is, isobutylene-isoprene rubber (IIR), ethylene-propylene-diene monomer (EPDM) rubber, and chlorinated paraffins (CP) are examined. Curing, mechanical, and dynamic properties of rubber compounds were studied. As per our findings, it was shown that IIR/EPDM/CP rubber combination is a good material to produce diaphragms of vulcanizers. It was able to increase the service time of the diaphragm under cyclic loading deformation at high temperatures as compared to conventional rubber materials. Rheometric characteristics, namely, torque maximum, torque minimum, cure time, initial curing time, and cure rate index, were determined using an oscillating rheometer.

Samples with quantum dots (QDs) of narrow-gap semiconductors of the A3B5 group (indium antimonide) and the A2B6 group (mercury selenide) have been studied. The absorption spectra of the investigated QDs are analyzed and the correspondence of the maxima in the spectral characteristics to the model representations of the calculated electronic energy spectrum for this materials is assessed. It is concluded that used model representations requires refinement, primarily due to the fact that studied objects are nanocrystals with complex geometry. Keywords: quantum dots, indium antimonide, mercury selenide, electronic energy spectrum.

Samples with quantum dots (QDs) of narrow-gap semiconductors of the A3B5 group (indium antimonide) and the A2B6 group (mercury selenide) have been studied. The absorption spectra of the investigated QDs are analyzed and the correspondence of the maxima in the spectral characteristics to the model representations of the calculated electronic energy spectrum for this materials is assessed. It is concluded that used model representations requires refinement, primarily due to the fact that studied objects are nanocrystals with complex geometry.

Samples with narrow-gap semiconductor quantum dots (QDs) of the A3B5 group (indium antimonide) and A2B6 group (mercury selenide) have been investigated. Absorption spectra of the QDs under study have been analyzed. Correspondence between maxima in the spectral characteristics and model concepts of the calculated electron energy spectrum for the materials under consideration has been estimated. It is concluded that the used model concepts should be refined, primarily concerning that the objects of study are nanocrystals with a complex geometry.

The impact of the shape of indium-antimonide quantum dots on some important electrical parameters is investigated by the analysis of their optical spectra, transmission electron microscopy, scanning tunneling microscopy, particle size measurements, and scanning electron microscopy. It is shown that the real shape (spherical and cubic models) of quantum dots with the same characteristic size has a noticeable effect on the energy spectrum of the investigated objects and, accordingly, their electrical and optical properties.

Features of the mechanisms of field electron emission in the “tunneling microscope probe–indium antimonide quantum dot (QD)” system have been revealed and analyzed in a temperature interval of 23–150°C. Analysis of the tunneling current–voltage characteristics led to the conclusion that there are different mechanisms of electron transport from the metal probe of tunneling microscope and field electron emission via discrete energy levels of indium antimonide QDs at various temperatures.

In this work, we studied the influence of the shape of the indium antimonide quantum dots of on some important electrophysical parameters by spectral characteristics analysis, transmission electron microscopy, scanning tunneling microscopy, a laser particle size analyzer, and scanning electron microscopy. It is shown that the real form of quantum dots (spherical and cubic models) at the same characteristic size will noticeably affect the energy spectrum of the investigated objects and, accordingly, their electrophysical and optical properties.

The paper identifies and analyzes the features of the mechanism of field emission in the tunneling microscope probe – indium antimonide quantum dot system in the temperature range of 23—150 °C. The analysis of the tunneling CVCs made it possible to conclude that there are different mechanisms of electron transfer from the metal probe of the tunneling microscope and the field emission of electrons through discrete energy levels of the indium antimonide quantum dot at different temperatures.

In this paper we have analyzed the broadening of the levels of the energy spectrum of indium antimonide quantum dots with a change of sample temperature. The position of the levels was determined by processing normalized differential tunneling current-voltage characteristics using the "cubic" model of a quantum dot. Comparison of the calculated values of spectrum broadening with experimental results showed qualitative and quantitative agreement between the results. It is concluded that with a decrease in the quantum dot size and, accordingly, an increase in the energy gap epsilon c1 - epsilon v1, the broadening in percentage will decrease, which should lead to an increase in the temperature stability of the electrophysical parameters.

The mechanisms of current transport through indium antimonide quantum dots (QDs) have been examined by analyzing normalized differential tunneling current–voltage characteristics. Electron tunneling with the discrete spectrum of QDs taken into account has been studied. The positions of the first three levels of their electronic spectrum have been estimated. It has been demonstrated that the mechanism of the observed field emission from a film structure of colloidal indium antimonide QDs is characterized adequately by the Morgulis–Stratton theory in the range of electric-field intensities corresponding to the experimental conditions.

The paper is devoted to investigation of mechanochemical halide modification of siloxane rubber (SKTV) using chlorine and fluorine-containing modifiers. Rubber compounds based on modified and original unmodified, siloxane rubbers were prepared. Rheological and curing properties of obtained rubbers were examined. In the established time optimum vulcanizates were obtained and their physical, mechanical and some special properties were studied. In order to study the molecular mobility of the modified rubbers ESR-spectroscopy study was carried out. The analysis of molecular mobility of modified rubbers has shown previously unknown regularities of mechanochemical halide modification of siloxane rubber using chlorine and fluorine-containing modifiers. The rheological and curing properties of the initial and modified rubbers were investigated. The application fields of halogen modified rubbers was determined.

Some important properties of the InSb and CdSe quantum dots, such as size and energy spectrum, were studied by method of normalized differential tunneling current-voltage characteristics. The results of size evaluation are qualitatively and quantitatively consistent with the results obtained by TEM and analysis of spectral dependence of absorption coefficient and luminescence with an error less than 15%. During the study it was also shown, that method of normalized differential tunneling current-voltage characteristics also allows us to analyze the energy spectrum of semiconductor quantum dots (position of the first three energy levels).

Abstract The mechanisms of current transport through indium antimonide quantum dots (QDs) have been examined by analyzing normalized differential tunneling current–voltage characteristics. Electron tunneling with the discrete spectrum of QDs taken into account has been studied. The positions of the first three levels of their electronic spectrum have been estimated. It has been demonstrated that the mechanism of the observed field emission from a film structure of colloidal indium antimonide QDs is characterized adequately by the Morgulis–Stratton theory in the range of electric-field intensities corresponding to the experimental conditions.

The photolysis of dry benzoyl peroxide (BP) at 77 K in the 480–236 nm range of wavelengths and an ethanol solution is studied via EPR. It is determined that the main photochemical process in irradiating BP at λ = 480–365 nm is the direct photodissociation of the O–O peroxide bonds and C–H bonds of benzene rings to form benzoyloxy radicals and atomic hydrogen, which likely forms via a two-quantum mechanism. The quantum yield of primary intermediates is φ ≈ 2.7 × 10−5. Upon subsequent irradiation of a sample using light with λ = 300–236 nm, benzoyloxy radicals release carbon dioxide and transform into phenyl radicals with a quantum yield of φ ≈ 3 × 10−4. At 120–145 K, phenyl radicals react with double bonds of aromatic rings of PB to form phenyl-substituted cyclohexadienyl radicals vanishing at 273 K. Quantum chemical calculations of the radical structures of photolyzed peroxide are made with the density functional approach (B3LYP/6-311g), and good agreement between the experimental and theoretical parameters is noted. Calculations show that in the structure of benzoyloxy radicals, the spin density is distributed almost equally between the two oxygen atoms of the radical, due to the conjugation of the unpaired electron to the lone p electron pair on the oxygen atom of the C=O group. In the photolysis of BP solutions in ethanol at λ ≥ 365 nm, solvent radicals form via sensitized photolysis through the reaction between primary benzoyloxy radicals and solvent molecules.

This work is devoted to study of halide mechanochemical modification of nitrile-butadiene rubber (BNCS-18AN) with a chlorine-containing reagent. In previous studies, the optimal parameters for modification were established. The modification was carried out in a laboratory rubber mixer. The obtained halogen-containing rubbers were investigated using ESR spectroscopy. Rubber compounds based on obtained chlorinated butadiene-nitrile rubbers (CNBR), were prepared and their tensile stress-strain properties and curing characteristics were investigated. Vulcanization of rubber compounds was carried out under the established optimal conditions. Physical and mechanical properties of the rubbers were determined. Subsequent studies showed the most probable regularities of the mechanochemical halide modification of nitrile butadiene rubber (BNCS-18AN) with a chlorine-containing modifier (CHCl) in a rubber mixer.

The field electron emission from individual grains on the surface of Si and III–V semiconductors, namely, gallium arsenide, indium arsenide, and indium antimonide is investigated by scanning tunneling microscopy. From the correspondence of the functional dependence of the I – V characteristic to the theory, the emission mechanism is determined as direct tunneling through a depleted or enriched subsurface layer at the voltages V < 1 V and the tunneling emission from the surface electronic states at the voltages V > 1 V. A field-emission threshold of (1–5) × 10 6 V/cm is obtained, which is significantly lower than the values for metals and carbon. The determining factors of this emission mechanism are the Schottky effect, the localization and size quantization of “light” electrons in the surface area of III–V semiconductors, and the presence of a subsurface depletion layer in silicon. According to the data obtained for the values of the field-emission threshold, indium antimonide in the form of submicron grain particles is the most efficient field emitter.

AbstractThe field electron emission from individual grains on the surface of Si and III–V semiconductors, namely, gallium arsenide, indium arsenide, and indium antimonide is investigated by scanning tunneling microscopy. From the correspondence of the functional dependence of the I – V characteristic to the theory, the emission mechanism is determined as direct tunneling through a depleted or enriched subsurface layer at the voltages V < 1 V and the tunneling emission from the surface electronic states at the voltages V > 1 V. A field-emission threshold of (1–5) × 10^6 V/cm is obtained, which is significantly lower than the values for metals and carbon. The determining factors of this emission mechanism are the Schottky effect, the localization and size quantization of “light” electrons in the surface area of III–V semiconductors, and the presence of a subsurface depletion layer in silicon. According to the data obtained for the values of the field-emission threshold, indium antimonide in the form of submicron grain particles is the most efficient field emitter.

Abstract The possibility of obtaining indium antimonide nanoparticles by method of liquid chemical etching was analyzed. The dependence of obtained nanoparticles size on the etching time and composition of the etcher has been investigated. The nanoparticles were etched in solutions prepared on the basis of the peroxide-ammonia mixture; cetyltrimethylammonium bromide, a cationic surfactant, was used to stabilize the surface of the nanoparticles. The obtained quantum dots of indium antimonide were studied by the methods of differential normalized tunnel current-voltage characteristics, electron microscopy, particle size analysis and spectral dependence of the absorption coefficient.