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The high-rate convergence of copper cylindrical shells with a diameter of 48 mm and a wall thickness of 4 mm is studied at various intensities of explosive loading. Two structural mechanisms of the loss of stability of the radial deformation front are described. A diagram of structural changes reflecting the successive stages of the convergence process is presented. An interrelation is found between the number of protrusions on the shell surfaces during their corrugation at the intensity of explosive loading. It was found that high-rate longitudinal deformation during convergence has a pulsating character. It was found that the temperature rises to ~500°С in the center of the converged shell and that it can be higher than 1000°С at a high rate of spall-pore collapse.

Results of a field–experimental study on the applicability of continuous-cast medium-carbon 55 grade steel sparingly alloyed with chromium to the manufacturing of hardness IV and V class grinding balls 40 mm in diameter are presented. The possibility of the stable production of hardness IV class grinding balls is shown since chromium added in small quantities facilitates the hardness stabilization over the half of the ball radius and increases the volumetric hardness by 2–3 HRC figures. The established increase in the volumetric hardness did not allow for the HRC 57 level to be reached to certify the balls as the hardness V class products. Rational process variables have been recommended to ensure the production of 40-mm-in-diameter grinding balls for the V hardness class of continuous-cast medium-carbon 55 grade steel on the ShPS 30–80 ball-rolling mill.

An analytical model of the equation of state is developed based on theoretical ideas about the structure of TATB. ^The model is validated against experimental data obtained in static and dynamic experiments. The theoretically sound equation of state was used to match different experimental data in order to maximize the use of empirical information. It is expected that the use of the equation of state will increase the accuracy of the description of thermodynamic parameters of unreacted TATB in numerical simulations of shock-wave and detonation processes.

Metallography has been used in this study to investigate copper samples cut from cylindrical shells collapsed under shock wave loading. Spallation phenomena (either the shell is divided into concentric rings, or a wide zone with spallation cavities and cracks is formed), which occur in shells under shock wave loading are considered. High-rate deformation during inertial convergence heals pores and cracks. Traces of healing remain in the microstructure. Various cases of nonradial convergence, when a stable circular deformation front is lost, are observed. Bends appear on the thin-walled shell and the shell crumples during its converging. Periodically arranged protrusions form on the inner surface of the thick-walled shells. They subsequently join together, converging to the center of the shell. A wave-shaped relief, protrusions, dents, and corrugation on the outer surface indicate the loss of stability.

It is shown that one area for development of the internal market for aluminum is formation of a branch (geographical) structure for processing it, including use of recycling scrap accumulated within a region based on newly created production with a broad range of finished product output. Under conditions of a typical regional producer ALTEK dynamics of forming the level of mechanical properties within the scope of a round cast workpiece manufacture – extrusion – heat treatment production system are studied. It is shown that the indices achieved are adequate for fulfilling the requirements of the majority of users. At the same time, further development of the production cycle is possible by creating a complete operational control system for both semiproduct and finished product quality.

It is shown that linear-dendritic block copolymers poly(N-isopropylacrylamide)–block–polyphenylenegermane can be prepared by the polymerization of N-isopropylacrylamide in the presence of bis(pentafluorophenyl)germane followed by activated polycondensation with tris(pentafluorophenyl)germane. The properties of the dilute solutions and Langmuir monolayers of the functional polymers and the linear-dendritic block copolymers of N-isopropylacrylamide are studied.

The behaviors of two systems are considered: a low-molecular system (a binary mixture of low-molecular components) and a polymer system (mixture of a macromolecules and a low-molecular dopant) whose components reversibly bind to form dimers capable of liquid-crystal ordering. The general theory of binary-mixture structuring, where two processes occur—self-assembly of mesogenic dimers of the mixture components and their self-organization—is presented. The theory demonstrates general laws of the behavior of low-molecular and polymer systems as well as differences related to the features of polymer thermodynamics.

The article deals with the influence of the power level of the generation of a CO2 laser on its electrical and dynamic characteristics. The dependences obtained will make it possible to take into account the effect of the generation level on the discharge characteristics when calculating the stability of systems for stabilizing the radiation power of gas-discharge lasers.

Purpose: The purpose was to measure the concentrations of various cytokines and growth factors (including vascular endothelial growth factor [VEGF] and pigment epithelium-derived factor [PEDF]) in the vitreous of patients with proliferative diabetic retinopathy (PDR) and to investigate interaction between inflammatory and proliferative factors in the genesis of PDR. Materials and Methods : Vitreous samples from 32 eyes with PDR and 25 eyes without diabetes mellitus and signs of DR (control) were collected. Vitreous concentrations of VEGF, PEDF, monocyte chemotactic protein-1 (MCP-1), interleukin-4 (IL-4), IL-6, IL-8, IL-10, IL-17A, and secretory immunoglobulin A (sIgA) were simultaneously measured using enzyme-linked immunoassay. Results : Vitreous levels of VEGF, PEDF, IL-17A, IL-6, IL-8, IL-4, and sIgA were significantly (Π < 0.05) higher in eyes with PDR compared to control. The concentration of VEGF was more than 17-times higher than in control, and the concentration of PEDF was not changed oppositely and was also higher (1.45-times) compared to control, that may indicate disturbances of compensatory mechanisms in angiogenesis regulation in PDR. Significant (Π < 0.05) positive correlations were observed between vitreous concentrations of VEGF and IL-17ΐ (r = 0.45), VEGF and IL-8 (r = 0.48), VEGF and IL-4 (r = 0.51), PEDF and IL-17ΐ (r = 0.48), PEDF and IL-8 (r = 0.59), MCP-1 and PEDF (r = 0.72), MCP-1 and IL-8 (r0 = 0.45), IL-4 and IL-17ΐ (r = 0.65), IL-4 and IL-8 (r = 0.71), IL-8 and IL-17ΐ (r = 0.59). Conclusions: Significantly raised levels of inflammatory and proliferative factors and numerous positive correlations between them may demonstrate a significant role of activation of vascular proliferation and local inflammation in the pathogenesis of PDR.

The current-voltage characteristics of a glow discharge flowing in narrow long tubes corresponding to helium-new lasers are investigated. Studies were conducted on a specially designed layout, which includes discharge tubes of different diameters. The model was connected to the pumping and filling system, which allows varying the gas content and the working pressure. The discharge was excited in mixtures based on helium and neon. A technique has been obtained for the analytical calculation of current-voltage characteristics, based on taking into account the gas heating during discharge.

We demonstrate superconducting niobium nitride nanowires folded on top of lithium niobate substrate. We report of 6% system detection efficiency at 20 s-1 dark count rate at telecommunication wavelength (1550 nm). Our results shown great potential for the use of NbN nanowires in the field of linear and nonlinear integrated quantum photonics.

In this work current-voltage characteristics of a glow discharge flowing in narrow long tubes are investigated. The studies were carried out on a specially developed layout, which includes discharge tubes of various diameters. The model was connected to the pumping and filling system, which allows varying the gas content and working pressure. The discharge was excited in pure carbon dioxide gas, as well as mixtures based on it: carbon dioxide with nitrogen in the ratio 1:1, carbon dioxide with helium in the ratio 1:8, and also carbon dioxide, nitrogen and helium in the ratio 1:1:8. An approximating expression is obtained for the CVC in the form of a power function including the discharge current, the length of the discharge gap, and the longitudinal potential gradient calculated in the automated mode.

Specific features of heating of a mechanically activated 3Ni + Al mixture during synthesis in the thermal explosion mode are considered. Based on the authors’ criterion of the minimum curvature of the heating rate logarithm as a function of inverse temperature, the activation energies of the synthesis process in the above-mentioned system are determined and the temperature intervals of the Arrhenius dependence and self-deceleration segments on thermograms are found. A kinetic function structure analysis shows that synthesis follows the laws of homogeneous kinetics with the reaction order close to unity. The calculated activation energies are anomalously low, as compared with conventional self-propagating high-temperature synthesis in this system.

Already commercialized and some of the most promising technologies of nitrogen oxide reduction in automotive diesel exhaust are compared. The Boreskov Institute of Catalysis (Siberian Branch, Russian Academy of Sciences) is developing an advanced method for the selective catalytic reduction of NO x with synthesis gas produced on board by the catalytic conversion of diesel fuel. The activity of the Ag/Al2O3 catalytic system in NO x reduction by H2 + CO admixtures is studied for both a model composition of the exhaust gas and under real diesel operation conditions.

Special features of linear and nonlinear propagation of coherent light beams in two-dimensional photorefractive photonic lattices optically induced in the lithium niobate crystal doped with iron are experimentally investigated. The two-dimensional gratings are formed by consecutive recording of two one-dimensional photorefractive gratings in the crystal. Experiments were performed using He-Ne laser irradiation with a wavelength of 633 nm.

To study the nature of anisotropy effects in samples of polymer (PVA) films containing nanoparticles of magnetite the depth selective conversion Mossbauer spectroscopy (for layer-by-layer phase and magnetic analysis), saturation isothermal remanent magnetization (SIRM) and natural remanent magnetization measurements (NRM) in three mutual—orthogonal directions and atomic force microscopy were used. These investigations revealed formation of “in plane” direction of linear Fe 3 O 4 nanoparticles chains and their number increase with nanoparticles concentration growth in the samples. Significant influence of polymer matrix on macroscopic magnetic properties was revealed from the temperature dependences of saturation magnetization and Mossbauer spectra.

To perform the catalytic conversion of natural gas to synthesis gas, a compact radial reactor supplied with a structured porous metal catalyst has been designed. The reactor was tested at normal pressure using natural gas and air. The reactor can operate without preheating of the inlet gas mixture. A novel structured porous metal catalyst was developed on the basis of the 7% Ni/α-Al 2 O 3 commercial catalyst and Ni-Cr powders. The catalyst is characterized by a low hydraulic pressure drop and a high tortuosity coefficient of the regular structure. The coefficient of heat conductivity of the structured catalyst and the coefficient of mass transfer between a gas flow and the catalyst were determined in special experiments. The catalyst temperature and outlet gas concentrations were experimentally investigated with respect to the gas-air flow rate and methane concentration in the mixture. The catalyst temperature drop along the reactor radius was no higher than 230 °C. The maximum catalyst temperature does not exceed 1090 °C for all runs. At volumetric flow rates of the gas mixture of 4000-40 000 h -1 and O 2 /CH 4 ratios of 0.6-0.9, methane is completely converted, and the maximum space time yield (STY) of the reactor is about 1 L of CH 4 per second per liter of reactor. A mathematical model for this process was developed. The results of modeling agree well with the experimental data. One possible application of the developed syngas generator in internal combustion engines is discussed.

The results from studying the transient processes induced by a shock in porous TATB, obtained using an original and tested method based on employing the soft X-ray component of synchrotron radiation, are presented. The method enables us to determine the parameters of a shock-wave striker, the distribution of velocity and density behind the front of the shock and detonation wave, and the characteristics of flow after a shock wave is reflected from a rigid wall, all in one experiment. Trials with charges 1.8 and 1.9 g/cm3 in density show that modes such as the absence of detonation and initiation in direct and reflected shock waves, are possible depending on the loading conditions.

The pulsed NMR, isopiestic and pycnometric methods are applied to investigate the physicochemical properties of softwood [GOST (State Standard) 9571-89] and hardwood [GOST 28172-89] celluloses, as well as flax cellulose [GOST 10330-76, 9394-76], both in the initial state and subjected to chemical treatment. Possible changes occurring in the supramolecular structure of a polymer are analyzed. The structural and sorption characteristics of the investigated samples are calculated. Their water absorption capacities are determined.

The velocity of delayed hydride cracking in irradiated E110 alloy (0.01% hydrogen) and zircalloy-2 (0.078% hydrogen) is predicted. It is shown that the velocity of cracking in VVER and RBMK fuel-element cladding is lower than in the stronger BWR fuel-element cladding. The maximum predicted velocity of cracking in E110 alloy is 2·10–7 m/sec and is reached at 533 K. Below this temperature, the cracking process in both materials studied follows the Arrhenius law with activation energy 53–56 kJ/mole.

In this work current-voltage characteristics of a glow discharge in neon and helium in long discharge tubes of various diameters at different pressures are investigated. Dependence of the longitudinal gradient of the plasma potential in the positive column of the pressure for different diameter of the discharge tube is found. Depending on the accommodation coefficient of electrons in various diameters, pressures and gas filling discharge gaps are obtained. The possibility of using described techniques for the calculation of parameters of the plasma glow discharge laser is shown.

Calculations of the quasiperiodic and stochastic regimes of three‐dimensional convection of a silicon melt (Pr = 0.015) have been performed for a rotating vessel whose complicated shape is typical of crucibles used in growing crystals by the Czochralski method. A large set of data on the structure of the convection and the spectral composition of pulsations has been obtained. The influence of the rotation of a crystal and a crucible on the convection and the thermal state of a melt has been investigated.

In this work an expression for the dynamic resistance of a glow discharge flowing in long tubes is obtained and analyzed. The expression describes the physical processes occurring in the positive column of a glow discharge. The frequency dependences of the active and reactive components as well as the dynamic resistance module for the discharge conditions corresponding to CO2–lasers have been calculated. Based on the simulation results developed a computer program in the C# programming language for modeling the dynamic resistance discharge of glow discharge lasers.

The kinetics of heterogeneous decomposition of methylsilane in a pumped hot-wall reactor were studied just below the critical partial pressure for homogeneous decomposition. The activation energies of the process derived from gas-phase conversion measurements and from deposition rates of SiC were found to be equal (about 230 kJ/mol). The nature of the diluent (H2, He, or Ar) has only a weak effect on the reaction order in methylsilane (m ≃= 1 ), as well as on the composition and structure of amorphous Si0.53C0.47 films.

Some features of discrete diffraction of light, which manifest themselves in the possibility of its linear and nonlinear localization in one or several waveguide elements, in photorefractive photonic superlattices optically induced in lithium niobate crystals, and in planar optical waveguides based on this material, have been experimentally investigated.

In this paper features of the structure formation of nanoscale coatings (TiN)–(AlN)– (Ti–Al–N) in the vacuum arc discharge plasma are considered. The composition and structure of the formed nanoscale coatings are studied. The main factors influencing the quality of the formed coatings are shown.

In this work experimental current-voltage characteristics of a glow discharge occurring in long tubes for a wide range of discharge conditions (pressure, diameter of the discharge tube, nature of the gas) were obtained. On the basis of the current-voltage characteristics was calculated the longitudinal potential gradient in the positive column. With the help of the developed computer program was calculated the electron temperature for discharge conditions corresponding to the experiment. The technique is based on the use of the balance equations of ionization in gas discharges occurring in long narrow tubes, and provides the possibility for calculation of the discharge plasma parameters, both in pure gases and in multicomponent mixtures. Based on the experimental values of the longitudinal potential gradient in the positive column and the calculated values of the electron temperature was calculated the dependence of accommodation coefficient for the electrons from the discharge conditions. The compliance between the experimental and reference data was obtained.

When a metal plate is subjected to a strong shock impact, its free surface emits a flow of particles of different sizes (shock-wave "dusting"). Traditionally, the process of dusting is investigated by the methods of pulsed x-ray or piezoelectric sensor or via an optical technique. The particle size ranges from a few microns to hundreds of microns. The flow is assumed to include also finer particles, which cannot be detected with the existing methods yet. On the accelerator complex VEPP-3-VEPP-4 at the BINP there are two experiment stations for research on fast processes, including explosion ones. The stations enable measurement of both passed radiation (absorption) and small-angle x-ray scattering on synchrotron radiation (SR). Radiation is detected with a precision high-speed detector DIMEX. The detector has an internal memory of 32 frames, which enables recording of the dynamics of the process (shooting of movies) with intervals of 250 ns to 2 μs. Flows of nano- and microparticles from free surfaces of various materials (copper and tin) have been examined. Microparticle flows were emitted from grooves of 50-200 μs in size and joints (gaps) between metal parts. With the soft x-ray spectrum of SR one can explore the dynamics of a single microjet of micron size. The dynamics of density distribution along micro jets were determined. Under a shock wave (~ 60 GPa) acting on tin disks, flows of microparticles from a smooth surface were recorded.

The Zeldovich-Neumann-Doering theory of ideal detonation allows one to describe adequately the detonation of charges with near-critical diameter. For smaller diameters, detonation velocity can differ significantly from an ideal value expected based on equilibrium chemical thermodynamics. This difference is quite evident when using non-ideal explosives; in certain cases, this value can be up to one third of ideal detonation velocity. Numerical simulation of these systems is a very labor-consuming process because one needs to compute the states inside the chemical reaction zone, as well as to obtain data on the equation of state of high-explosive detonation products mixture and on the velocity of chemical reaction; however, these characteristics are poorly studied today. For practical purposes, one can use the detonation shock dynamics model based on interrelation between local velocity of the front and its local curvature. This interrelation depends on both the equation of state of explosion products, and the reaction velocity; but the explicit definition of these characteristics is not needed. In this paper, experimental results are analyzed. They demonstrate interrelation between the local curvature of detonation front and the detonation velocity. Equation of detonation front shape is found. This equation allows us to predict detonation velocity and shape of detonation wave front in arbitrary geometry by integrating ordinary differential equation for the front shape with a boundary condition at the charge edge. The results confirm that the model of detonation shock dynamics can be used to describe detonation processes in non-ideal explosives.

The method of thermal desorption in a vacuum, with gaseous products recorded by mass-spectrometry, was applied to study the state of the surface of diamond and graphite.

Studies of iodine stress corrosion of fuel-element cladding in water-cooled reactors began in the sixties in connection with leaking of elements under transient conditions. These studies led to some understanding of the effect iodine on the strength of zirconium alloy cladding, and to consideration of possible mechanisms of iodine cracking, diffusional mechanisms among them. The development of a failure model involving iodine diffusion has been restricted by the concept of slow permeation of iodine in zirconium and its alloys, although no quantitative expression for iodine diffusion in zirconium alloys has been obtained. Considering that experimental studies of corrosion cracking make it seem advisable to make use of a diffusional model for working out the mechanism of stress corrosion cracking. In this article, the authors have undertaken the task of determining the parameters of iodine diffusion in Zr-1% Nb alloy used for VVER-1000 fuel element cladding, in a temperature range close to the working temperature.

X-ray photoelectron spectroscopy was used to investigate the surface functional groups of natural diamond and graphite. An analysis of the spectra of the core shells made it possible to establish the presence of hydroxyl (ether), carbonyl, and carboxyl-like groups. It is shown that it is possible to identify acid oxyfunctional groups within the framework of a cluster approach.

To study the nature of anisotropy effects in samples of polymer (PVA) films containing nanoparticles of magnetite, depth selective conversion Mossbauer spectroscopy (for layer‐by‐layer phase and magnetic analysis), natural remanent magnetization Jn measurements in three mutual — orthogonal directions and atomic force microscopy were used. These investigations revealed formation of the “in plane” direction of linear Fe3O4 nanoparticles chains and their number increases with nanoparticles concentration growth in the samples.

The problem of long-term storage of nuclear-safe ceramics (NSC) supposedly containing plutonium, transition and rare-earth metals oxides is connected first with the necessity of the plutonium isotope enhanced diffusional release prognostication at storage temperatures. For lack of experimental features on diffusion processes in NSC, our estimations are based on the literature data for thermal-activated and radiation-enhanced diffusion (TAD and RED, respectively) of U and Pu in UO2 and (U, Pu)O2 oxides.

The effect of low-pressure He plasma on properties of nanoporous organosilicate glasses low-k films with 24% and 33% open porosity is studied. The influence of ions, VUV radiation, and metastable atoms are extracted separately using a special experimental system designed for this purpose. The low-k films treated in He plasma were exposed to O or H atoms in the downstream of high-pressure O2 or H2 rf discharge. The changes in chemical composition and structure occurring in low-k films were measured before and after all treatments. The loss probabilities of oxygen and hydrogen atoms on the low-k film surface were measured for both treated and pristine films. It is shown that the film pretreatment in He plasma leads to the noticeable densification of the top surface layer up to complete sealing all the films studied. The sealing layer prevents O atoms from deep penetration to the film bulk and carbon extraction. The sealing mechanism related to the joint impact of low-energy ions and VUV photons with metasta...

Using the CNDO method, a number of hydroxy-containing systems were calculated. The results are compared with IR spectroscopic data on the frequencies and acidity of surface OH groups and their dependence on the electronegativity of the atom to which the OH group is bonded.

A study of the effect of the conditions of obtaining aluminum hydroxide and alumina on the properties of the powders showed that fine milling and washing with water increase their dispersion and decreases the content of the alkali compounds. After fine milling and washing with water, the phase composition of the commercial-grade alumina undergoes a change: its a-Al2O3 content decreases due to the transformation into the hydrated forms of Al2O3. Fine milling and washing of the alumina obtained from anode slimes lead to a significant reduction of the content of the alkali compounds in it and significantly improve the degree of sintering at 1650°C at a specific surface less than that of the milled commercial-grade alumina, i.e., the sintering temperature is 100°C lower than that required for the milled alumina of KirAF.

Cluster models of the MgO surface have been calculated by a semi empirical method. The energies of transitions between the surface states localized on ions of definite coordination are dependent on their coordination numbers. The lower transition energies correspond to a lower coordination number of oxygen ions.

Cluster models calculated by a semiempirical CNDO method are used to describe properties of the surface hydroxy groups of beryllium oxide. The results are compared with those obtained from IR studeies and with data on BeO energy bands.

A description and justification is given of a technique for measuring the spectral dependences of the absolute quantum yields of iodine atoms in the l(2P1/2) and I(2P3/2) states in photolysis of RI organic iodides. Data are presented and interpreted for RI = CF3I, C2F5I, CF3CFICF3, C3F7I, and CF3OCF2CF2I. The proposed model is checked by means of calculations of the electron density distribution in RI.

Cluster models of MgO surface OH groups have been studied by the semi-empirical CNDO method. The calculated stretching vibration frequencies of OH bonds and localized electron excitation energies on the OH-groups are shown to depend on the oxygen atom coordination.