Home – Home – Jornals – Atmospheric and Oceanic Optics 2020 number 3

High-pressure phases (ringwoodite, maskelynite, and jadeite) present as coarse-grained fragments in the shock-melt vein of the Dhofar 922 L6 chondrite were studied by scanning electron microscopy and Raman spectroscopy. Ringwoodite and jadeite crystallized from melted plagioclase and olivine fragments, respectively, at the cooling-decompression stage. We assume that the high contents of Fe and Mg in maskelynite-jadeite aggregates are due to a miscibility gap in the hedenbergite-jadeite and diopside-jadeite joins at ~600 and ~700 °C, respectively. The P - T conditions of the formation of shock-melt veins are estimated at >19 GPa and >2150-2300 °C.

The mineral composition, petrography, and petrochemistry of middle Cambrian diopside porphyry basalts of the Ust’-Sema Formation in Gorny Altai are considered in comparison with ankaramites of different geodynamic settings. The basalts of the Ust’-Sema Formation are enriched in phenocrysts of high-Mg clinopyroxene (Mg# ≤ 94) (20 to 40-50 vol.%) with a high content of Cr2O3 (up to 1.11 wt.%), enclosed in the clinopyroxene-plagioclase microlitic groundmass. In addition, there are minor phenocrysts of saussuritized plagioclase (An49-71), olivine replaced by secondary minerals, amphibole with Mg# = 55.7-68.2, and Cr-spinel with Cr# = 36.2-41.7. Inclusions of Cr-spinel in high-Mg clinopyroxene are richer in Cr (Cr# ≤ 72.8). The basalts of the Ust’-Sema Formation are chemically heterogeneous and are subdivided into two main groups: high-Ca (MgO = 7.98-14.77 wt.% and CaO/Al2O3 = 1.0-1.8) and low-Ca (MgO = 2.84-9.89 wt.% and CaO/Al2O3 = 0.2-0.9). The obtained data on the high-Ca basalts of the Ust’-Sema Formation show that the rocks are similar to the reviewed ankaramites and thus can be assigned to this type of rocks. The low-Ca basalts of the Ust’-Sema Formation might have resulted from the fractionation of ankaramitic melt in intermediate magma chambers. The Gorny Altai ankaramites formed through the melting of the wehrlitized suprasubductional lithospheric mantle during the closure of the Paleoasian Ocean.

Data on gabbro-dolerite pyrite-chalcopyrite-pyrrhotite, quartz vein sphalerite-chalcopyrite, and associated early and late gold-telluride-palladium mineralization of the Krutoi ore occurrence (Pai-Khoi Ridge, Yugor Peninsula) are presented. The early (magmatic) gold-telluride-palladium mineralization is represented by minerals of the ternary system Ag-Au-Cu, palladium antimonides and stibiotellurides, and platinum arsenides, and the late (hydrothermal) one, by minerals of the binary systems Au-Ag and Au-Pd as well as mercury, lead, and silver tellurides. Sudburyite and testibiopalladite have been first found in the Krutoi ore occurrence; moreover, testibiopalladite has been first discovered in the Pai-Khoi Ridge. Their chemical compositions and Raman spectra have been examined. The results of sulfide sulfur, oxygen, and carbon isotope studies of calcium-containing minerals of chalcopyrite-quartz veinlets suggest assimilation of the material of the host deposits by the ore-forming mantle fluids. The fluid inclusions in the veinlets are divided into nitrogen-methane and carbon dioxide-nitrogen according to the composition of the gas phase. It has been established that the mineral-forming fluids were poorly saturated with gas. Magnesium and calcium salts were predominant in them. The temperature of the formation of quartz in the chalcopyrite-quartz veinlets is close to 300-490 °C, and sphalerite-chalcopyrite and associated late gold-telluride-palladium mineralization formed at temperatures not exceeding 260 °C.

We present results of geochemical studies of the upper Mesozoic deposits of the Strelka and Malaya Tynda depressions and U-Th-Pb (LA-ICP-MS) geochronological and Lu-Hf isotope-geochemical studies of detrital zircons from these deposits. It is shown that the Strelka and Malaya Tynda depressions, adjacent to the Mongol-Okhotsk orogenic belt in the north and extending along the boundary between the southern framing of the North Asian Craton and the orogenic belt, are marginal troughs. These troughs are filled with thick beds of Mesozoic marine (at the bottom) and continental (at the top) metaterrigenous rocks, with an increase in the grain size of clastic material up the section; the rocks should be regarded as molasses. The results of U-Th-Pb geochronological studies of detrital zircons from metaterrigenous rocks of the Strelka and Malaya Tynda depressions, on the one hand, and the eastern part of the Mongol-Okhotsk Orogenic Belt, on the other, show that orogenic processes in the east of the belt were completed at the Early-Middle Jurassic boundary. The depressions began to form after the complete closure of the Mongol-Okhotsk basin and the formation of an orogenic structure at its place. Then they were filled with material supplied both from the Selenga-Stanovoi and Dzhugdzhur-Stanovoi superterranes on the southern framing of the North Asian Craton and from the Mongol-Okhotsk Belt, which was a mountain-folded structure in the Middle Jurassic.

A 1.8 m thick core of the Holocene (7.9 ¹⁴C kyr BP) sediments of Lake Itkul’ (Novosibirsk Region) has been studied. Based on the geochemical and lithostratigraphic properties of the bottom sediments, we have established the following stages of the lake evolution: (1) the beginning of sedimentation, 7.8-7.0 14С kyr BP; (2) extreme shallowing with a probable complete drying, ~7.0-5.5 14С kyr BP; (3) rise in the water level, ~5.5-4.3 14С kyr BP; (4) repeated shallowing, 4.3-2.8 14С kyr BP; and (5) subsequent watering, 2.8-0 14С kyr BP. At present, the lake again tends to shallowing. We have established that Lake Itkul’ has mineral sediments with a high content of carbonates (up to 64%). The high concentrations of HCO₃^- and Ca²⁺ and stable saturation (S/St > 1) of the surface water cause a shift of the carbonate-calcium equilibrium toward the carbonate formation. The studied authigenic carbonates are aragonite and fine-grained aggregates of poorly crystallized calcite particles with different Mg contents. Aragonite is both biogenic (mollusk and ostracode shells) and chemogenic (formed during the lake shallowing). In addition to carbonates, the lacustrine sediments contain mixed-layer aluminosilicates, feldspars, and quartz. The presence of pyrite throughout the sediment section indicates reducing conditions and the activity of sulfate-reducing microorganisms. Carbonates (especially aragonite) are significantly enriched in strontium. Manganese does not form its own minerals but is present as an isomorphic impurity in authigenic carbonates.

We propose and test a method for probabilistic estimation of the scale and structure (distribution of helium concentrations in free gas, accumulations of different sizes, localization zones, and stratigraphic complexes) of helium and helium-containing gas resources. Summarizing the available geological information about the structure of the sedimentary cover and data on the revealed accumulations of helium-containing gases, we have first made probabilistic estimation of the scale and structure of their resources as well as helium resources in the central and southern areas of the Lena-Tunguska province. The forecast results will serve as a reliable basis for geological and economic estimation of helium resources, for long-term planning of gas field development in East Siberia and the Republic of Sakha, and for helium industrialization in these regions.

We propose a facies-stratigraphic zoning of the Vasyugan and Georgievka horizons in the sedimentary cover of the West Siberian Basin, including the southern part of the Kara Sea. Based on the typification of well sections and taking into account the paleogeography of the Callovian-Kimmeridgian deposits, we have recognized 12 regions with different structures of the Vasyugan and Georgievka horizons. The Purpei-Vasyugan area is divided into three subareas according to the structure of the Vasyugan Formation including the petroliferous horizon Yu₁. Transition zones have been recognized between the Vasyugan Formation and the bordering Abalak, Tatar, and Naunak formations along the western, southern, and eastern boundaries of the area, respectively. The results of zoning of the Callovian-Kimmeridgian deposits, including the petroliferous horizon Yu₁, can be used on planning of exploration work, for selecting standard facies models, and for predicting the petrophysical properties of a reservoir.

This is an overview of existing methods for joint analysis and inversion of geophysical data, including conventional techniques and alternative options based on simultaneous and sequential inversion of different data sets and posterior analysis of separate inversion results. Advantages and disadvantages of different methods are compared using examples of typical cases, and the respective practical recommendations are provided for each method.

XIV International Conference on pulsed lasers and their applications (AMPL) was held in Tomsk in September 15-20, 2019. The Conference was traditionally devoted to results of theoretical and experimental studies of physical and chemical processes in laser active media; the newest active media and pumping methods; new laser technologies; fundamental topics of laser physics; application of lasers in science, engineering, medicine and other spheres; discussion of problems and difficulties in development of laser-based equipment; new optical technologies.

The results of experimental studies of the influence of pumping conditions on the spectral and temporal characteristics of IR Ar I laser radiation upon excitation of the active medium by a pulsed inductive longitudinal discharge are presented. The lasing was obtained at transitions of neutral argon atoms at wavelengths of 1213, 1240, 1270, 1694, and 1791 nm in pure argon and its mixtures with helium and neon. The optical pulses length was (5 ± 1) ns (FWHM); the radiation energy attained 0.1 mJ.

An IR laser, which operates in the region 900-2050 nm at transitions of Xe I atoms and is pumped by pulsed inductive cylindrical discharge, has been created. Xenon and its mixtures with helium and argon were used as active media. The influence of the composition of the active gas medium on the intensity of Xe I atom radiation was experimentally studied. The lasing spectrum consisted of three lines with wavelengths of 904.5, 1733, and 2026 nm. The intensity ratio strongly depended on the composition of the active medium. The duration of the optical radiation pulses attained 8 ± 1 ns (FWHM).

When the Ne + Tl gas-vapor mixture was excited by an electron beam, laser generation was obtained and investigated with excitation of the upper levels in the charge exchange reaction at ion lines with λ = 1,922; 1,385; 0,595; 0,695 and 0,707 mm; the lasing at the first two lines was obtained for the first time. In the studied range of pump parameters, a linear dependence of the lasing power on the pumping power was revealed, indicating the efficiency of electron-beam excitation. An average radiation power of 44 mW was reached at λ = 595 nm at a pulse repetition frequency of 1 kHz with an efficiency of ~ 0,06%. A numerical simulation of the laser energy characteristics was carried out.

A transverse-pumped sodium vapor active element has been developed. A possibility of lasing at resonant transitions upon active medium excitation using nanosecond pulses of various energies and spectral conditions has been experimentally investigated. The medium was pumped using a dye laser and a CuBr laser. Radiation was detected on sodium D lines when pumping with CuBr laser yellow emission line.

Lasing energy of 10 mJ was obtained for the first time under nitrogen pumping by a pulsed inductive discharge with a pulsed power higher than 1 MW. The lasing pulse length of the inductive nitrogen laser created was (8.5 ± 0.5) ns (FWHM). The lasing was obtained at two wavelengths of 337.1 and 357.7 nm. The lasing beam had a ring cross section with a diameter of about 33 mm and a width of about 2 mm.

The conditions for the formation of THz radiation in ZnGeP₂ single crystals when generating a difference frequency are considered. It is shown that two-frequency laser pumping sources with lasing pulse duration of ~ 1 ns are required to implement effective THz radiation. It is suggested to use a “generator - amplifier” system of a strontium vapor laser (at the Sr I transitions in the region 3 mm and Sr II in the region 1 mm) as such a source of IR radiation. The conditions of population inversion are considered, under which the lasing pulse duration is ~ 1 ns in the active medium of the strontium vapor laser. It is shown that the use of the “generator -amplifier” system can increase the average lasing power of the strontium vapor laser in proportion to the increase in the volume of active medium of the amplifier.

A laboratory prototype of a complex for high-speed visual-optical diagnostics of plasma-chemical synthesis in powder mixtures is described. The processes are initiated by microwave radiation of a gyrotron. The laboratory prototype allows imaging processes in the reactor and spectra of the resulting radiation. The prototype includes video cameras, spectrometers, and a synchronization system and suggests a possibility of installing an active filtration system based on metal vapor active media. The resulted images of the process of synthesis of various ceramic micro- and nanoparticles are presented. It is shown that the use of temporal filtering of optical images does not completely suppress the background radiation impact.

The results of laboratory experiments on recording the backscattered IR laser radiation from aerosol particles containing organic impurities are presented. The studies were performed at the laboratory test bench according to the lidar sensing scheme along a controlled optical path. Aqueous aerosol and aqueous solutions were used as model media. Aerosol and solutions contained organic impurities: tryptophan, isopropyl alcohol, glycerin, and nicotinamide adenine dinucleotide (NADH). For research in the IR range, the experimental complex was modified. The UV laser was replaced with an IR laser during this upgrade. A liquid-nitrogen-cooled mercury-cadmium-telluride based IR detector was used to record backscatter signals. A possibility of using IR lasers with scanning the radiation frequency for remote sensing of atmospheric organic aerosols is shown.

The results of lidar probing of tropospheric aerosols in Kaliningrad, Russia (54°N, 20°E) are presented. The observations used a two-wave atmospheric lidar (with wavelengths of 532 and 1064 nm), which allows investigation of properties of troposphere up to altitudes of 10-12 km. The measurements carried out in the period 2011-2018 made it possible to determine the features of the vertical structure and the dynamics of aerosol particles. The analysis of the observations revealed intensification of the waves in the range of acoustic-gravity waves in the troposphere during the passage of a solar terminator.

The paper presents an experimental setup, experiments on measuring and calculation of light pressure on structural materials for different angles of incidence of light. This calculation is necessary to determine the materials lighting properties and the total forces moment of solar pressure. As a construction material, industrial metal fiber (net-textile) was used. Net-textile is the material of large-diameter spacecraft antennas. More than 4 000 experimental measurements of the transmittance and reflection coefficients of net-textile were carried out for the calculation.

Based on the numerical simulations in ANSYS software the design of the monomorph (unimorph) deformable mirror has been developed. The control electrodes pattern, which allows reproducing aberrations up to 5th order (the first 21 Zernike modes) on the light aperture with high fidelity, was chosen. All important characteristics of the monomorph mirror were calculated: electrodes influence functions, reproduction errors of the given aberrations, gravitational sag of the mirror, mirror surface deformation due to ambient temperature changing, thermal deformations and thermal field due to the incident laser beam, and natural frequencies of the mirror. The results show a possibility of the effective use of this mirror as an element of adaptive optics systems.

This paper deals with the convergence of spectral and conditional spectral models that are used to simulate a stochastic structure of the sea surface undulation and rogue ocean waves. We study the convergence of spatial-temporal and spatial models.

This paper deals with a difference scheme of second order of approximation for one-dimensional Maxwell's equations using the Laquerre transform. Supplementary parameters are introduced into this difference scheme. These parameters are obtained by minimizing the difference approximation error of the Helmholtz equation. The values of these optimal parameters are independent of the step size and the number of nodes in the difference scheme. It is shown that application of the Laguerre decomposition allows obtaining a higher accuracy of approximation of the equations in comparison with similar difference schemes when using the Fourier decomposition. The finite difference scheme of second order with parameters was compared to the difference scheme of fourth order in two cases. The use of an optimal difference scheme when solving the problem of electromagnetic impulse propagation in an inhomogeneous medium yields the accuracy of the solution compatible with that of the difference scheme of fourth order. When solving the inverse problem, the second order difference scheme makes possible to attain a higher accuracy of the solution as compared to the difference scheme of fourth order. In the considered problems, the application of the difference scheme of second order with supplementary parameters has decreased the calculation time of a problem by 20-25 per cent as compared to the fourth order difference scheme.

In this article, we discuss a fourth-order accurate scheme based on non-polynomial spline in tension approximations for the solution of quasi-linear parabolic partial differential equations. The proposed numerical method requires only two half-step points and a central point on a uniform mesh in the spatial direction. This method is derived directly from a continuity condition of the first-order derivative of a non-polynomial tension spline function. The stability of the scheme is discussed using a model linear PDE. The method is directly applicable to solving singular parabolic problems in polar systems. The proposed method is tested on the generalized Burgers-Huxley equation, the generalized Burgers-Fisher equation, and Burgers' equations in polar coordinates.

We study all possible symmetric two-level difference schemes on arbitrary extended stencils for the Schrödinger equation and for the heat conductivity equation. We find the coefficients of the schemes from the conditions under which a maximum possible order of approximation on the main variable is attained. From a set of maximally exact schemes, a class of absolutely stable schemes is isolated. To investigate the stability of the schemes, the Neumann criterion is numerically and analytically verified. It is proved that the property of schemes to be absolutely stable or unstable significantly depends on the order of approximation on the evolution variable. As a result of the classification it was possible to construct absolutely stable schemes up to the tenth order of accuracy on the main variable.

An approach to studying the influence of the electric field on the flame with separate consideration of the effects of curving and extending of the plane flame is proposed. The degree of deformation can be used as a factor determining the action efficiency. Based on the results obtained by combined application of particle image velocimetry and spectral zonal registration, the change in the degree of deformation of the flame of a Bunsen-type burner located between flat electrodes is estimated.

The PIV and PLIF OH methods were used to experimentally study the structure of a jet impinging on a flat surface with swirl and combustion of a propane-air mixture with an equivalence ratio of 0.7 at distances between the nozzle and the surface H / d = 1 and 3 and in the absence of the impinged surface. The swirl parameter was 0.41 and 1.0, and the Reynolds number was 5000. It is concluded that for both values of the swirl parameter, the presence of the surface leads to the formation of an extended central cone-shaped recirculation zones. For H / d = 3 and 2, the intensity of OH fluorescence near the impinged surface and inside the recirculation zone significantly reduced. This effect is presumably caused by a decrease in the temperature of combustion products in the recirculation zone, including in the neighborhood of the flame front.

Combustion of FTi70 industrial ferrotitanium containing 65.9% of Ti and a model alloy of iron with 30.6% of Ti in nitrogen is described. It is shown that the degree of nitriding of the combustion products of industrial ferrotitanium is low. The distribution of nitrogen along the sample diameter is uneven. The dilution of the alloy with the final product increases in the degree of nitriding. The study of the combustion of the model alloy concludes that the degree of nitriding increases along with the melting point of the initial alloy. The composition of the combustion products of ferrotitanium is described.

The numerical simulation method is used to analyze the influence of a unit cell size on the burning rate of a donor-acceptor system. The cell size determines the fragmentation of a combustion wave. It is determined during calculations that, with an increase in the unit cell size, the average burning rate of the sample decreases. The combustion limits of a cellular system with external heat removal from the sample surface are determined: an increase in the unit cell size contributes to expansion of the combustion limits of the sample. The principal possibility of the synthesis in a chemical furnace for the cellular formation of the structure of the reacting system is shown.

Physicochemical changes occurring in an oxide shell of boron particles during heating are extremely important for the oxidation and combustion of boron, including those in solid propellant compositions. The Al₂O₃, MgO, MgF₂, Al, and Mg impurities were experimentally discovered in an oxide layer on boron particles obtained by various methods. The goal of this work is to determine the effect of these impurities on the thermal behavior of boron oxide, with particular attention paid to evaporation of B₂O₃. The temperature and thermal effects of reactions between the components are thermoanalytically determined, and the processes of dehydration, melting, and evaporation of boron oxide are analyzed in detail. The enthalpy of evaporation of boron oxide, starting at a temperature above 1 300^oC is experimentally determined, and is equal to 347 ± 3 kJ/mol. An interaction is observed between magnesium fluoride and boron oxide at a temperature of about 1 000^oC with a mass loss corresponding to the content of magnesium fluoride and the formation of gas-phase boron fluoride. It is established that boron dissolved in oxide has virtually no effect on the evaporation of the boron oxide melt, while the addition of Al₂O₃ or MgO significantly increases its thermal stability. Based on the analysis of the results obtained, an assumption is made about the effect of impurities on boron activity in the processes of boron ignition and combustion.

The effect of the modification of ASD-4 micron-sized aluminum powder with iron oxide on its oxidation in air is investigated. The modification consisted of coating the surface of metal particles with gel based on Fe(OH)(HCOO)₂ and ethylene glycol monomethyl ether, CH₃OC₂H₄OH, followed by heat treatment in air. It was found that the presence of iron oxide generally has a positive effect on the dynamics of oxidation ASD-4 powder when heated in air. The oxidation rate of modified powders increases with increasing content of iron oxide in them. X-ray diffraction analysis using a synchrotron radiation source under heating to 1 000 ^oC showed that the samples contained only the main phases γ-Al₂O₃ and α-Al₂O₃, γ-Fe₂O₃ and α-Fe₂O₃, and other iron oxides or intermetallic compounds were not found. At a mass concentration of 10 % Fe, an earlier appearance of the phase α-Al₂O₃ is observed and the exothermic peak of maximum heat release is shifted to lower temperatures (893 ^oC) compared to the unmodified ASD-4 powder (1 045 ^oC).

An approach to the mathematical modeling of the suppression of thermal decomposition and flame burning of forest fuels is proposed which is different from the well-known approaches in that a pyrolyzed FF layer is represented as a heterogeneous structure with high porosity and the thermophysical characteristics of this layer are described within the framework of additive mathematical models of thermal conductivity, heat capacity, and density. Experimental studies of the main thermophysical characteristics (thermal conductivity, heat capacity, thermal diffusivity) of typical FFs were performed. Mathematical modeling of heat- and mass-transfer processes under the conditions considered was performed, and the suppression characteristics of the destruction reaction of a typical FF were determined using the values of thermophysical characteristics established in the experiments. The ranges of the integral characteristics of FF flame suppression while varying the thermophysical characteristics of FF within the permissible limits were identified.

A comparative analysis of maximum pressures in a solid rocket motor obtained using exponential and real pressure dependences of the solid propellant burning rate on was performed. It is shown that at high exponents in the burning law, there is a large (tens of percent) difference between the maximum motor pressure obtained by the above two methods. In the case where the exponent is in the range of 0.3–0.4, the exponential pressure dependence of the burning rate overestimates motor pressure only by 2–3%.

This paper describes an experimental study pertaining to laser ignition of igniters of liquid rocket engines operating on such fuels as O_2g + kerosene, O_2g + ethanol, and O_2g + H_2g, and to how they ignite the fuel of a model combustion chamber. A quartz fiber based optical spark plug is described, which allows for multiple ignition of the igniter and the combustion chamber without replacing the spark plug. This study also touches upon possible types of pulsed lasers used in the laser ignition system, a fiber-optic laser igniter that remain insulated and efficient at a combustion chamber pressure of up to 10 MPa and more than 100 ignition cycles.

Cellular detonation in suspensions of two fractions of submicron and nano-sized aluminum particles is studied by numerical methods. Approaches of mechanics of heterogeneous media are used. The transition from the continuum to free-molecular regime of the flow around the particles is taken into account in the processes of interphase interaction. Particle combustion is described within the framework of the previously developed model of reduced kinetics. The results calculated for two-dimensional flows in a plane channel reveal significant differences from suspensions of two fractions of microparticles, where degeneration of transverse waves is observed. In the present study, weakly regular and irregular cellular structures are formed, which is also confirmed theoretically on the basis of the acoustic analysis based on the Barthel method.

Results of experimental investigations in a flow-type annular cylindrical combustor with an outer diameter of 503 mm are reported. The influence of air addition to products of continuous spin detonation of CH₄/mH₂-air mixtures on the parameters of detonation waves, pressure in the combustor, and specific impulse is considered. It is demonstrated that addition of air to detonation products increases the velocity of continuous spin detonation, the pressure in the combustor, and the thrust, whereas the specific flow rate of the fuel decreases.

A closed mathematical model of continuous spin detonation with the chemical kinetics equation correlated with the second law of thermodynamics is developed for a hydrogen-air mixture within the framework of quasi-three-dimensional unsteady gas-dynamic formulation. The model takes into account the reverse influence of the oscillation processes in the combustor on the injection system of the mixture components. For comparisons with experimental data, the numerical simulations are performed for the geometric parameters of the flow-type annular combustor with an outer diameter of 306 mm used in the experiments. For the flow rates of the mixture varied in the interval 73.1-171.3 kg/(s·m²), the one-wave, two-wave, and three-wave regimes of continuous spin detonation are calculated, the flow structure is analyzed, the specific impulses are determined, and comparisons with experimental data are performed. It is shown that the use of a simplified single-stage kinetic scheme of hydrogen oxidation, which was used in some investigations, for simulating continuous spin detonation leads to results that differ from the experimental data by several times.

Shock-wave initiation of chemical reaction in pressed pellets of a stoichiometric mixture of Al and CuO powders in a steel tube was studied. The dynamics of the chemical transformations in the heterogeneous flow of reaction products of the mixture during dispersion of the pressed pellet material in a rarefaction wave was investigated. From the results of pyrometric measurements, the maximum brightness temperature of chemical reaction products was ≈3 500 K.

This paper presents the results of measuring the thresholds of explosive decomposition of PETN-coal under the action of laser radiation pulses (λ= 1 064 nm and τ= 14 ns). Samples whose thickness is 1 mm and whose densities are 1.1 and 1.7 g/cm³ with inclusions of submicron particles of brown coal (750 nm) are investigated. A minimum explosive threshold of 1.8 J/cm² is reached with a concentration of inclusions of 0.5 % (by weight). The explosion is adiabatic. Composites with a density of 1.1 g/cm³ have a scattering matrix. A minimum explosive threshold of 2.3 J/cm² is obtained for a concentration of inclusions of 1 %. An extinction rate is estimated: k_ext = 135 cm^-1. Radiation is absorbed at a depth of <0.1 mm. Explosive decomposition in an unirradiated section develops according to the shock-wave mechanism of explosive combustion.

This paper describes an experimental study of the shock compression of samples simulating media with a given porosity using epoxy-based spheroplastics with filler made of glass microspheres with volume concentrations of 0.27 and 0.55. Shock adiabats in a pressure compression range of 0.1-1.2 GPa are obtained. The shock compression pressure at which the fracture of the used microspheres begins is estimated. The dependence between the nature of deformation and the concentration of microspheres in the sample is established.

This paper presents the results of metallographic analysis of the melting of C1 lead under shock-wave loading and unloading. Loading of lead samples in a titanium capsule was carried out by a plane shock wave using an aluminum projectile 6 mm thick, which was accelerated by detonation products of an explosive. The results of metallographic analysis of samples in the initial state, subjected to heat treated under normal conditions, and recovered after shock-wave loading are given. Melting traces were found in lead after shock-wave loading by a pressure of 25.6 GPa and subsequent unloading.