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The possibility of controlling the development rate of the incomplete staged of the discharge sliding over a solid dielectric surface is experimentally shown. Depending on the gas pressure and power supply voltage, the development rate of the incomplete stage of the discharge in air sliding over the solid dielectric surface is determined. It is shown that the discharge development rate varies from 1.4 × 106 to 7.8 × 106 cm/s in the pressure range from 10 to 60 Torr voltage from 4 to 12 kV. Emission of the second positive system of nitrogen dominates in the emission spectrum of the incomplete sliding discharge.

This paper presents an analysis on the possibilities of controlling the radiation pattern of Yagi-type multielement plasma vibrator antennas. The plasma vibrator antenna in its operating band is shown as a narrow-band filter. In a multielement linear plasma vibrator antenna, turning off a passive plasma vibrator makes it possible to control the beam width electronically.

Conditions for gas ionization in the field of a slow surface wave excited by a microwave source are considered. The gas ionization rate and the plasma density distribution over the radius of the discharge tube were studied by the optical method. The experiments were conducted in a dielectric tube with a radius much smaller than the tube length, the gas pressure being ~1–3 Torr. It is shown that the stationary distribution of the plasma density is determined by diffusion processes.

Characteristics of the plasma layer (a plasma antenna of dipole type), excited by the radiation of a transmitter such as the carrier density distribution over the radius of the dielectric tube (near the boundary) and the growth rate of the plasma region along the tube length are considered. It is shown that it is possible to distinguish such typical dimensions as the radius of the dielectric tube, the radius of the plasma column, and the thickness of the skin layer, and, depending on relationships between these dimensions, consider the influence of the transition layer on excitation of the surface wave in the plane or cylindrical symmetry.

A reflector plasma array antenna is investigated. A plasma array with a controlled pattern is created with the help of a discharge creeping over a dielectric surface. The scattering microwave radiation pattern is calculated for the vertical and horizontal polarizations of the radiation incident on the plasma array.

Lasers, sources of coherent UV and vacuum UV radiation, plasmachemical reactors, reactors for cleaning fouled gases, etc., can be classified as devices the working medium of which is plasma formed as a result of the interaction of a high-current relativistic electronic beam with gas. Efficiency of such devices which are united under the common name “systems of injection gas electronics” (SIGE) depends mainly on the efficiency of energy transfer from a beam to gas (ηg = Wg/Wb) and that of the transform of the energy transferred to gas into the energy of the ultimate product Win (ηin = Win/Wg). As a special case of SIGE, an experimental bench laser is considered. The new efficient method of pumping is supposed to be implemented on this laser to optimize the energy contribution ηg and useful output ηin.

The aggregate stability of aqueous sols prepared from the OX-50 Aerosil is investigated at pH 35-10 in the KCl and BaCl2 concentration range 10−4−10−1 M. It is demonstrated that the results obtained can be explained in the framework of the classical Derjaguin-Landau-Verwey-Overbeek theory of the stability of lyophobic colloids. It is revealed that, for the OX-50 nanoparticles, there is a region of parameters of the dispersion medium for which long-range interactions between particles due to the predominance of the molecular (dispersion) attractive forces over the ionic electrostatic forces can lead to coagulation of the sol.

Fluorescence spectra induced by a He-Ne laser in a complex biological medium (blood plasma) are studied. The statistical analysis of the spectra reveals regular correlations between the spectral parameters and concentration of substances known as porphyrinic pigments. The common factors of the spectral characteristics of fluorescence spectra are chosen as the diagnostic parameters. A model for differential diagnostics based on factor analysis is proposed.

The equations are obtained for effective coefficients of correlated random fields of permeability and porosity in a fractal porous medium. The fields have log-normal distributions. The refined perturbation theory is formulated that uses some ideas of the Wilson renormalization group. The theoretical results are compared with the results of a direct numerical modeling and the results of the conventional perturbation theory. The advantages of the refined perturbation theory over the conventional perturbation theory are demonstrated.

The impact of metal plates is considered within the framework of the model of a viscous incompressible fluid. The beginning of the wave-formation process in the model is equivalent to the initial stage of origination of instability of a steady flow in Landau’s scenario. To establish the correspondence between the model and the real process, a series of experiments is performed on a symmetric impact of plates made of an aluminum alloy with identical impact angles and different velocities of the contact point. At high values of the Reynolds number and, hence, at high velocities of the contact point, wave excitation is shown to have a soft character; at lower values of Reynolds number, there exists a metastability region where the wave-excitation regime is rather hard; at even lower Reynolds numbers, no action can lead to wave formation, as it follows from the theory. Thus, Landau’s model of origination of instability of a steady fluid flow is found to agree with the process of wave formation in an oblique impact of metal plates.

The infrared transmittance spectra and dark conductivity of wafers fabricated from nanocrystalline silicon powder (nc-Si) have been studied. The initial nc-Si powder is first synthesized by laser-induced silane dissociation, with the temperature of the surrounding buffer gas varied from 20 to 250°C, and then compacted at pressures from 108 to 109 Pa. It is found that compaction of the nc-Si powder results in formation of Si-H, Si-CHx, and Oy-Si-Hx structures (x, y=1–3). The formed structures break down under annealing, with the Si-H and Si-CHx complexes disintegrating at the lowest annealing temperature (t = 160°C). The dark conductivityof the nc-Si wafers is shown to increase along with the buffer gas temperature at which the starting powder was prepared. Two temperature regions are found in which the dark conductivity behaves in radically different ways. At wafer temperatures T ≥ 270 K, conductivity is mediated by free carriers, whereas, at lower temperatures, electron transport is governed by hopping conduction over localized states in the band gap.

A mathematical model describing the form of the surface of propagating wave energy is suggested.

Ultrafine powders with a mean particle diameter (20–30) nm were synthesized from high purity SiH 4 by laser-induced gas phase reactions and studied by transmission electron microscopy. Results showed that the powders consisted of Si crystals with an amorphous shell, or spherical Si crystals without the shell. Twinning of crystals often took place. Both types of crystals: poly and mono were observed inside an amorphous shell. The mechanism of the formation of all types of nanoparticles is proposed.

Subgrid modeling of a filtration flow of a fluid in an inhomogeneous porous medium is considered. An expression for the effective permeability coefficient for the large‐scale component of the flow is derived using the scale‐invariance hypothesis. The model obtained is verified by numerical simulation of the complete problem.

The development of a high-voltage discharge above the water surface is considered. The peculiarity of the observed type of discharge is explained by the process of water evaporation.

The experimental results on breakdown characteristics of a discharge gap containing water vapor are presented. The results obtained show that the breakdown voltage between metal electrodes placed above water and when one electrode is immersed in water significantly increases at a saturated vapor temperature of 90°C and above. This effect can be an explanation of the features of the electric discharge development above the water surface.

This review paper presents the results obtained during the development and study of three high-power wide-aperture CO 2 lasers (λ=10.6 μm) pumped with a discharge controlled by an electron beam. In developing these lasers, the method of formation of a space discharge at elevated pressures due to uniform ionization of the working mixture by an electron beam with an energy of some hundreds of kiloelectron-volts was used, which was proposed by researchers at the Instute of High-Current Electronics (IHCE).

Macrodefects of the structure of samples produced by explosive compaction of an aluminum powder were examined. The areas of the new contact particle surfaces produced by high-rate deformation were measured by stereological methods. The eddy current method was used to measure the macroscopic electric conductivity of the compacts. From these data, the mean sizes and number of macrodefects per unit volume of a compact were calculated. The techniques employed can be useful for an analysis of the structure of composite materials produced by various methods.

The propagation of a plane shock wave of constant intensity over a powder metallic medium in the presence of a magnetic field is considered. The compression of the magnetic field by a shock–induced conducting wave in the medium is studied in detail. It is assumed that the magnitude of the macroscopic electric conduction increases monotonically from zero to its maximum and is constant behind the shock–wave front. The problem of determining the magnetic field is solved under the assumption that the characteristic time of field variation is much greater than the time required for convection and diffusion through the front. The dependence of the magnetic field on the coordinate and the time inside the shock–wave front is established.

The gauge transformation of the hydrodynamic equations of superfluidity and superconductivity is considered. The vortex and heat momentum densities are defined and their evolution equations are derived. The physical meaning of these quantities is analyzed. The Lagrangian invariants of the new set of equations, which are similar to those obtained by Hollman for classical hydrodynamics, are derived.

Electromagnetic processes in flat thermocouples made of metals with varying conductivity under conditions of dynamic loading with a traveling load are studied. The distribution of the electric potential over the thermocouple surface is shown to carry information on the velocity field and the strained state of the thermocouple materials. An experimental procedure for validating various theoretical models of continua under high-velocity deformation is proposed. As an illustration, results of numerical simulations for flow of an ideal incompressible fluid are presented.

Compaction of a powdered aluminum alloy reinforced by high-strength metallic and ceramic fibers in a flat layer under a running explosive loading is studied. The values of the compaction pressure of the matrix material and of the failure pressure of ceramic fibers are found. The structure of the compacts obtained and the character of failure are analyzed.

Equilibrium statistical mechanics is used for describing two-dimensional vortices in an unbounded incompressible ideal fluid. Both the energy and angular momentum integrals and a set of invariants are taken into account. The latter follows from the condition that any vorticity distribution can be obtained from an initial distribution by a differentiable areas-preserving transformation. The equations for the statistically equilibrium vorticity and passive admixture distributions are derived. It is argued that taking subsidiary invariants into account weakens the arbitrariness associated with the choice of a finite-dimensional approximation of the flow. The case in which the vorticity cloud behaves like a thermodynamic system undergoing an ordering phase transition is discussed.

A simple and sufficiently accurate method is proposed for estimating the parameters of shockwave loading of porous materials under conditions of complete compaction of the material to the density of a monolith.

The foil-method and metallographic studies of powdered material particle orientation in specimens subjected to loading are used to show that upon regular reflection of colliding shock waves the flow in the region where they branch is homogeneous. A well expressed high-speed flow of material behind the Mach wave from exists for irregular reflections. In the shock wave branching region, two qualitatively different flowregimes are possible: without high-speed flow slippage, and with such slippage. Flow without slippage is found at shock wave amplitudes below some threshold value, dependent on the initial density of the powdered metal. A transition zone in the form of a viscous wake exists at the boundary of the high-speed and low-speed flows. A numerical solution of the model problem of mixing of two homogeneous flows of viscous liquid was carried out. By comparing calculation results to experiments which recorded characteristic viscous wake parameters, it was established that the effective viscosity of a shock-compressed copper powder with dispersion < 60 μm comprises ∼0.01 m2/sec, with the material remaining in the solid state at a density close to that of a monolithic specimen.

A method has been developed for measuring the temperature of a cumulative jet using the thermoelectric effect. The temperature of a copper jet formed under shock loading of a specimen with a semispherical cavity has been measured.

Methods and results of tests of biomedical parameters of a new accessory circulation apparatus based on implantable axial blood pump are discussed in this work. Bench tests were directed toward determining energy parameters and pump-induced injury of blood cells. The results of the tests allowed efficiency of the developed system to be evaluated within a wide range of working load.

Thermoelectric effects in a bimetal plate loaded by a gliding detonation wave are explored. The electric–potential distribution is measured on the surface of such a thermocouple which is nonuniformly heated as a result of high–rate deformation. Experimental results are used to determine the stress state of the metal and are compared to calculations performed within the framework of the Mie—Gruneisen model.

A system of dissipative modes in an incompressible flow of space dimensions d>or=2 is considered. The self-induced phase chaos is shown to arise in the motions of very small scales, which are fed by the large-scale ones through repeated nonlinear interactions. This property is used to derive the equations for the Fourier amplitudes. Solutions similar to those derived previously for turbulent fluctuations in the dissipation range are obtained. Properties of the short-scale intermittency are analysed. The authors show that no coherence and intermittency can be built up at asymptotically high wavenumbers.

The method of spectroscopy with temporal and spatial resolution was used in an investigation of the collision, with a ring-shaped obstacle, of a plasma created by interaction of laser radiation with a solid target. This collision excited autoionizing states of C II and C III ions. The velocities of ions with diiferent ionization multiplicities, as well as the electron density ne and the electron temperature Te were determined by an expanding plasma flux, and the density and temperature were also found for the case when the plasma collided with the obstacle. The kinetics of excitation of autoionizing states was determined when the pressure of a buffer gas in the vacuum chamber was varied. The spatial distributions of ne and Te were used to analyze the mechanism of excitation of the autoionizing states.

A pulsed TEA CO2 laser was used in an investigation of the influence of the pump radiation parameters (mode composition, wavelength, pulse duration), of the focusing conditions, of the properties of the material (absorption coefficient), and of the operating conditions (temperature) on the efficiency of conversion to the second harmonic and on the angular dependences of phase matching in ZnGeP2 crystals. The calculated results were found to be in good agreement with the experimental data.

The authors have improved a procedure for preoperatively preparing patients with progressive drug-resistant fibrocavernous tuberculosis. This has been achieved by using ultraviolet laser irradiation (wavelength 248 nm) of the cavity walls in the multimodality treatment of this disease. Endocavitary laser irradiation increases preoperative preparation and surgical treatment and reduces the number of postoperative complications.

Collision of metal plates is treated in the frames of model of a viscous incompressible liquid. In such terms a wave formation process corresponds to an initial stage of occurrence of turbulence in accordance to L.D.Landau’s scenario. To verify conformity between the theoretic description and the real process, a series of experiments on symmetric collision of aluminum plates is carried out with identical collision angles and different velocities of a collision point. It is established that with great magnitudes of the Reynolds number R and consequently, with the big velocities of a collision point, excitation of wave formation has soft type, with smaller magnitudes of R there is an area of metastability where the mode of excitation has rigid type, and with even smaller magnitudes of R any influence does not lead to wave formation in conformity with Landau’s theory.

The wafers of thickness 60μm÷100μm were made at compression of nanocrystalline silicon (nc-Si) powders in a range of pressures from 108 up to 109 Pa. Optical and electrical properties ofthese wafers have been investigated by means of registration of IR transmission spectra and dark conductivities. Analysis of IR absorption spectra of wafers shows that structures Si-H, Si-CHx and Ox-Si-Hy (x,y=1÷3) are formed at a pressing of nc-Si powder. We believe that these structures are formed at pressing of powder after break of links in network of a silicon atoms and consequent saturation of Si-dangling bonds by hydrogen, carbon or oxygen atoms which are located on free surfaces of silicon particles. It is found that dark conductivity of a wafer is depending on temperature of buffer gas in which original powder is formed. Wafers which have been made of the powders created at higher temperatures of a buffer gas flow had more pronounced hydrogen microstructure and higher dark conductivity. Analysis of dark conductivity vs. temperature T of the wafer shows that at the temperatures higher than approximately 270K the conductivity follows Arrhenius behavior with single activation energy, and at lower ones, conductivity is depending on T as: σ=(A/T1/2)-exp(-B/T1/4). Last equation allows asserting that variable-range hopping is mechanism oftransport in nc-Si wafers at temperatures T

A new method is proposed for investiging the behavior of the nucleus of a living cell with damage to different parts. A laser set-up based on a projection microscope with image time scan has been designed. A new type of N2-laser is used as an external source of the affecting radiation. The construction allows one to irradiate a biological object with the radiation from a copper laser which forms the base of the projection microscope.

The found bactericidal activity of ozone and oxygen mixture containing ozone, 10 mg/l, and ozoned solutions of furacilin (dilution 1:5000) and chlorohexidine (0.05%) against the nonspecific microflora and Mycobacteria tuberculosis allowed them to be used in the treatment of 55 patients with pleural empyema. Analyzing the outcomes of treatment in these patients versus 59 matched patients indicated that local ozone therapy accelerated sanitation and stimulation of reparative processes in this disease on the average by a fortnight. Local ozone therapy used in the preoperative preparation of patients with pulmonary tuberculosis and pleural empyema reduced the number of purulent postoperative complication to 17.7% versus 30.4% in the controls, enhanced the efficiency of multimodality treatment by 15.6% and reduced mortality by 9.5%. Analyzing the results of prevention of purulent bronchopleural complications after pleuropulmonectomy in 31 patients in the experimental group and in 35 in the control one showed that with local ozone therapy, complications occurred in 16.1 and 28.6%, respectively, and the efficiency of surgical management increased by 13.1% and mortality rates reduced by 9.6%.

Rocks have a developed porous structure that determines the fuid flows, waves and other proceses in them. It has been recognized that the scale invariant models may approximate the porous structure.

Silicon nanopowders produced by CO2-laser-induced decomposition of SiH4 in a flow reactor have been investigated. The particles of these powders can be described as polycrystalline silicon grains surrounded by a Si-amorphous shells.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The energy of the fully developed turbulence is excited at some large scale and is transferred through the inertial range to the viscous scales. While the transfer, the spatial intermittency is growing up and the small scale fluctuations occupy very small fraction of space [1]. Natural theoretical framework for the non intermittent pulsations is the original Kolmogorov (1941) scaling hypothesis [1] and the renormalization group technique [2], [3], [4], [5]. Intermittency induces corrections to simple scaling. Teodorovich [6] studied intermittency corrections by analyzing the infrared divergence within the framework of the field-theoretical renormalization group.

The main purpose of explosive compaction of porous reinforced and nonreinforced materials is the obtaining of strong compacts with the density close to the monolithic density. As is known, only the dynamic regime of explosive compaction allows for the solution of the problem. This way, the increase in the accuracy of calculation of the pressure value in a porous material results in the possibility of a more optimal selection of the initial loading parameters to provide the dynamic compaction regime throughout the depth of the sample under consideration. We present a technique for rough estimating loading parameters in powder materials for the case of strong shock waves. The comparison of the experimental results with the calculated shape of the shock wave has shown that the discrepancy of the results does not exceed 5%.

The investigation of the tendency in the development of benign hyperplasia of the prostate is a crucial point in decision on the treatment initiation, schedule and policy. In view of this, the knowledge of the intensity of cellular proliferation and secretion, i.e. prostatic functional activity, in line with detrusor assessment is held essential. Optimal criteria of this value can be obtained by histological examination of prostatic biopsies, investigation of androgen and estrogen receptors in distant adenomatous nodes, by comparison of various biochemical ingredients in prostatic secretion. Twelve biochemical ingredients of prostatic secretion were studied in patients of the control group, in those with prostatic stones, adenoma, chronic prostatitis. The treatment included either androgenic, or antiandrogenic, or estrogenic therapy. Prostatic secretion biochemistry analyzed mathematically showed fluctuations in zinc ions concentration which appeared most significant. It is inferred that zinc ion concentration in prostatic secretion must be considered a significant means of overall evaluation of prostatic function able to represent the capacity of glandular epithelium for response to androgenic stimulation or estrogenic (antiandrogenic) inhibition of secretory and proliferative processes.