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A method for measuring a gas flow rate is proposed based on ultrasonic sounding of the turbulent flow in a pipe with subsequent cross-correlation processing of signals passed through the flow in two pipe sections. It has been shown that information on the velocity of vortices is obtained from the pipe center due to focusing of ultrasound by a pipe wall. The velocities of vortices were measured using an ultrasonic flow meter and simultaneously by two mutually spaced heat–loss anemometers. Based on the correlation measurements of the time delay it has been shown that the velocity of vortices is less than the maximum flow velocity in the center measured using the Pitot–Prandtl tube. The possibility of measuring the volumetric gas flow rate using the data on the speed of vortices has been demonstrated.

Experience gained from the operation of nuclear power plants shows that emergencies or incorrect actions of the personnel may give rise to water hammer phenomena, which exert additional impacts on the pipelines and equipment. Condensation-induced water hammer (CIWH) is one of the most destructive kinds of water hammer. Experimental studies of CIWH were carried out in a number of scientific organizations around the world. The main features of the experimental facilities used in the world are considered. For studying the CIWH phenomena occurring in a horizontal channel, a special experimental test facility was set up in 2018 at the Elektrogorsk Research and Engineering Center for Nuclear Power Plants’ Safety (EREC). The facility’s test section and the parameters of experimental regimes are described. Fifty-two experiments were carried out on the facility under different initial and boundary conditions for three values of the water flowrate supplied to the facility (1, 3, and 5 t/h), two values of water temperature (30 and 60°С), and two values of vapor pressure in the test section (0.6 and 1.0 MPa). In all experiments, CIWH phenomena were recorded. As an example, one experimental regime was considered in detail, and the CIWH occurrence mechanism is described proceeding from the readings of pressure and level gages and temperature sensors. The described experimental regime was modeled using the RELAP5 and WAHA thermal-hydraulic codes. The effect that the size of nodalization diagram cells and the integration time step have on the computation results is analyzed. The significant amount of experimental points obtained from the study can be used for setting up a database for validating computer codes.

Compression of a fiber array with a deuterated target mounted on its axis is studied at the Angara-5-1 facility (3.5 MA, 100 ns). Cylindrical arrays with an initial diameter of 12 mm made from polypropylene fibers with a diameter of 13.4 µm are used. The number of fibers varied from 30 to 120. The target with the density of 0.08–0.2 g/cm3 and the diameter of 1 mm was made on the basis of deuterated polyethylene. A 10‑frame ultra-high-speed X-ray camera, optical slit scans, an integral X-ray pinhole camera, vacuum X-ray diodes, a crystal spectrograph, and neutron detectors are used to measure the plasma parameters in the Z‑pinch. It is found that the dynamics of plasma compression and evolution of local plasma formations, which are sources of neutrons and soft X-ray emission in the energy range of E > 150 eV, depend on the load configuration: the number of fibers, diameter, and density of the deuterated target. Efficient compression of the liner plasma, high concentration and temperature of the compressed target state, as well as the highest neutron yield (8 × 109 neutron/pulse) are observed in experiments with arrays with the fiber number of 60, inside which the target with the diameter of 1 mm and density of 0.2 g/cm3 was placed. The electron density and temperature of the hot plasma in local formations are estimated as ne ≈ 1021 cm–3, Te ≈ 1 keV, respectively. The average neutron energy was 2.6 ± 0.2 MeV. The intensity of the plasma formation $$\dot {m}$$ [in µg/(cm2 ns)] of polypropylene fibers under the action of the discharge current of the facility is determined in experiments with fiber arrays.

The generation of accelerated electron beams in a high-current Z-pinch formed by the implosion of wire cylindrical tungsten arrays on an Angara-5-1 facility is studied. The most intense characteristic and bremsstrahlung X-ray radiation of fast electrons is recorded from the central region of the pinch at the pin-ching stage. The transverse size of the radiation source in the characteristic tungsten radiation Lα is ~1.5‒1.8 mm, which is close to the transverse size of the radiation source in the soft X-ray emission (1‒1.5 mm). The current of accelerated electrons generated during the implosion of the wire array and the formation of a pinch is on the order of the Alfven current (IA). This result is consistent with the estimate of the current of accelerated electrons made from the measured characteristic radiation intensity Lα of tungsten under the assumption that the mean free path of fast electrons in a pinch is on the order of its length.

We have studied the fracture problem of layered media under combined dynamic loading. The effect of background harmonic vibrations on the amplitude of the main force pulse is analyzed. The features of fracture from such a combined action are demonstrated using a simple 2D model (a circular membrane on an elastic base). As the condition of adhesive layer rupture, the incubation time criterion is used. It is shown that the threshold amplitude of breaking action can be substantially reduced by correctly choosing the excitation frequency even for low intensities of the background field.

This article describes the experimental and theoretical studies of the mechanisms of failure of ABS polymer in the range of strain rates of 10–4–103 s–1 at different temperatures of testing (from an ambient temperature of 23 to 100°C). The alteration of the type of failure as a function of the strain rate and temperature is analyzed. Based on the structure–time approach, a model of the temperature–rate superposition is proposed.

The implosion of combined loads consisting of an outer wire (fiber) array and inner cylindrical target was studied experimentally at the Angara-5-1 facility (3.5 MA, 100 ns) at currents of up to 3.5 MA. The experiments were carried out with 12- and 20-mm-diameter outer arrays made of 15-μm-diameter aluminum wires, composite arrays made of aluminum wires and 25-μm-diameter kapron fibers, and arrays made of kapron fibers with a 1-μm-thick aluminum coating. The number of wires varied from 10 to 40. The targets were made of agar-agar or low-density deuterated polyethylene. The parameters of the Z-pinch plasma were determined using the Angara-5-1 diagnostic complex, which included optical streak cameras, X-ray frame cameras, X-ray detectors, X-ray pinhole cameras, neutron detectors, and a mica-crystal X-ray spectrograph. It is established that the plasma compression dynamics and the formation of local plasma structures generating neutrons depend on the load configuration: the array diameter, the number of wires (fibers), and the diameter and density of the target. The most efficient compression and the highest plasma parameters (the compression ratio and plasma temperature), as well as the highest neutron yield, were achieved in experiments with 12-mm-diameter aluminum wire arrays inside which a 1-mm-diameter deuterated target with a mass density of 0.3 g/cm3 was installed As a result of collision of the bulk of the array mass with the inner target, a compact pinch with a diameter of ≈0.5 mm forms. The pinch formation is accompanied by the generation of a soft X-ray pulse. The development of MHD instabilities in the pinch plasma results in the formation of multiple hot spots (HSs) on the pinch axis with a typical size of 200–300 μm and an electron temperature of 0.4–0.7 keV. The HS formation is accompanied by emission of neutrons with a mean energy of 2.7 ± 0.2 MeV. The maximum neutron yield achieved in these experiments was 2.6 × 1010 neutrons/shot.

Experimental and theoretical data for the strength performance of 1230 aluminum alloy under tension in the quasi-static and dynamic ranges of loading parameters are presented. Using the structural temporal approach and the sign-perturbed sums algorithm, the feasibility of raising the strain rate of a specimen by decreasing its geometrical size has been estimated.

Test results are presented for an additive material prepared of acrylonitrile-butadiene-styrene on a 3D printer. Dynamic tension experiments have been carried out using a tower-type drop hammer with an accelerator. Data obtained from different specimens demonstrate that high-strain-rate tensile experiments are feasible if the working part of the specimen is decreased. A theoretical analysis of test data using the incubation time criterion has been performed, and it has been found that analytical results are in good agreement with experimental data.

The possibility of control over the deformation and strength properties of annular structures by choosing temperature intervals of their operation is demonstrated. Identical mechanical actions on “metal muscles” at different temperatures results in considerable changes in their strength potentialities. A wire of diameter 2 mm made of Ti–Ni 50.6 at % alloy is tested.

The mechanical properties of the additive material prepared from acrylonitrile–butadiene–styrene plastic are studied experimentally on a 3D printer in the quasi-static and dynamic regimes. The strength curve describing the nonlinear dependence of the critical stress on the strain rate is constructed using the incubation time. The characteristic incubation time τ is determined by comparing the theoretical curve with the experimental data.

—A technique of ultrasonic action on ring-shaped titanium nickelide samples, which stimulates the shape memory effect, is described. The possibility of ultrasound-induced operation of ring-shaped force elements is shown.

Dynamic spalling tests have been run on two batches of 30KhN4M steel samples. Experimental data have been processed with the classical technique based on solution of the elastic wave equation. Three samples have been revealed that demonstrated the failure-delay effect under testing. The incubation-time criterion has been used to show the conditions of emergence of failure delay with the example of triangular loading pulses. A rate strength curve has been constructed for the other samples. It has been shown that the limiting strengths under dynamic loads considerably differ for samples from different batches despite the same chemical composition and static strength.

A method for processing the results of dynamic spall fracture tests, based on the exact solution of the wave equation, and its commonly used simplified version based on the assumed unique relation between the free surface velocity drop and the ultimate medium fracture stress, are analyzed. Using the considered exact solutions of the wave technique, tensile stress pulses during spalling are determined. The obtained stress levels at the fracture point are compared with the spall strength calculated by the velocity drop technique. The cases of agreement and disagreement of the results obtained using both techniques are shown. By the example of differently shaped loading pulses, possible scenarios of sample fracture are presented, in particular, the probability of the fracture delay effect is shown, which can be lost in the simplified processing method.

The processes of ultrasonically-assisted drilling (UAD) and the dynamic tests on split Hopkinson pressure bar (SHPB), fracture in which is implemented at various structural-scale levels, are considered. The simulation of UAD based on the Hertz contact problem and the structural−time criterion is presented. The problem of using the value of the fracture incubation time and its linear size obtained from the tests on SHPB in the simulation is considered. A principle of equal power is used for converting the strength parameters into another structural−scale level. The theoretical curve obtained in the simulation is compared with the results of experiments on conventional drilling (CD) and UAD.

The implosion dynamics of a pinch with a highly inhomogeneous initial axial distribution of the load mass was studied experimentally. A cascade array consisting of a double nested tungsten wire array and a coaxial inner cylindrical shell located symmetrically with respect to the high-voltage electrodes was used as a load of the Angara-5-1 high-current generator. The cylindrical foam shell was half as long as the cathode− anode gap, and its diameter was equal to the diameter of the inner wire array. It is shown experimentally that two stages are typical of the implosion dynamics of such a load: the formation of two separate pinches formed as a result of implosion of the wire array near the cathode and anode and the subsequent implosion of the central part of the load containing the cylindrical foam shell. The conditions are determined at which the implosion of the central part of the pinch with the foam cylinder is preceded by intense irradiation of the foam with the soft X-ray (SXR) emission generated by the near-electrode pinches and converting it into the plasma state. Using such a load, which models the main elements of the scheme of a dynamic hohlraum for inertial confinement fusion, it is possible to increase the efficiency of interaction between the outer accelerated plasma sheath and the inner foam shell by preionizing the foam with the SXR emission of the near-electrode pinches.

Results from experimental studies on the implosion of arrays made of kapron fibers coated with different metals (Al, In, Sn, and Bi) are presented. It is shown that the power, total energy, and spectrum of radiation emitted by the imploding array depend on the number of metallized fibers and the mass of the metal layer deposited on them but are independent of the metal characteristics (density, atomic number, etc.). Analysis of frame X-ray images shows that the Z-pinches formed in the implosion of metallized kapron fiber arrays are more stable than those formed in wire arrays and that MHD perturbations in them develop at a slower growth rate. Due to the lower rate of plasma production from kapron fibers, the plasma formed at the periphery of the array forms a layer that plays the role of a hohlraum wall partially trapping soft X-ray emission of the Z-pinch formed in the implosion of the material of the deposited metal layer. The closure of the anode aperture doubles the energy of radiation emitted in the radial direction.

The effect of induced transparency of thin Al foils radiatively heated by intense extreme ultraviolet (EVU) radiation has been observed. The radiation of the plasma of Z-pinches appearing under the compression of tungsten liners at the Angara-5-1 facility has been used as the radiation that heats the Al foil (peak illumination on the foil ~0.55 TW/cm2) and is transmitted through it. The photoabsorption has been studied in the formed aluminum plasma at temperatures of ~10–30 eV in the density range of ~1–20 mg/cm3 in the wavelength range of ~5–24 nm. Absorption lines of Al4+...7+ ions have been identified in the experimental spectrum. In addition, radiative gas-dynamic simulations of the foil heating and expansion have been performed taking into account radiation transfer processes.

The structure-time approach is used to develop an analytical model that makes it possible to predict the dependences of the acoustic cavitation threshold of water on temperature and background pressure. The calculated dependences are compared with the results of experiments carried out in the leading laboratories. It is demonstrated that the proposed approach allows the estimation of the effect of the acoustic field on the phase state of the substance under study. The calculated liquid-vapor phase curves for water in the presence of acoustic fields are presented.

Methods and results of studies of the radiation spectra of high-current Z-pinches with different elemental compositions are presented. To examine a wide spectral range (Ehν = 30–3000 eV), two diagnostics tools were used—a transmission grating and a reflecting mica crystal. The radiation characteristics of the pinch are determined by its elemental composition. For currents of 2–3 MA and low-Z elements (aluminum), the hard end of the radiation spectrum is represented by spectral lines with clearly pronounced K lines, while for high-Z elements (tungsten), the spectrum lies in the softer photon energy range and is quasi-continuous. Two methods of spectrum processing were used to determine the plasma parameters. The parameters of aluminum plasma were traditionally determined from the intensity ratios of the K lines taking into account the plasma transparency for these lines. The spectra of tungsten plasma were compared with the results of computer simulations of pinch compression with allowance for both magnetohydrodynamic and plasma radiation processes. The applicability of these methods of spectral analysis is discussed.

An analytical model is developed for the behavior of the cutting force during ultrasonic rotary polishing, and it is based on the concepts of dynamic fracture mechanics and the solution to the problem of impact surface fracture. The dependence of the threshold fracture energy obtained in the problem of erosion using a structure-time approach is used to construct the cutting force model. The dependences of the cutting force on the material feed rate and the rate of tool rotation are obtained, and the developed model is shown to be efficient to explain the effects observed in experiments.

Results are presented from measurements of the anisotropy of energy losses in high-current Z-pinches produced by the implosion of wire arrays at the ANGARA-5-1 facility at load currents of up to 4MA. The energy losses were measured in the radial direction and along the pinch axis from the anode side. The main diagnostics were time-integrated thermocouple calorimeters, nanosecond X-ray diodes (XRDs) with different filters, and a foil radiation calorimeter with a time resolution of 2 μs. The azimuthal anisotropy of energy losses was measured for different wire array configurations and different shapes of the high-voltage electrode. The presence of strong initial azimuthal inhomogeneity of the wire mass distribution (sectioned arrays), as well as the use of conical electrodes instead of plane ones, does not increase the azimuthal inhomogeneity of the total energy losses. For cylindrical wire arrays, energy losses in the radial direction are compared with those along the pinch axis. According to XRD and calorimetric measurements, the radiation yield per unit solid angle along the pinch axis is two to three times lower than that in the radial direction. In the axial direction, the energy flux density of the expanding plasma is two to three times lower than the radiation intensity. The measured radiation yield across the pinch is 2.5–5 kJ/sr, while that along the pinch axis is 1–2 kJ/sr. The results obtained by means of XRDs agree to within measurement errors with those obtained using the radiation calorimeter. It is found that the energy per unit solid angle carried by the expanding plasma in the radial direction does not exceed 10% of the soft X-ray yield. Analysis of the structure of time-integrated pinhole images and signals from the radial and axial XRDs shows that radiation emitted in the radial direction from the hot central region of the pinch is partially screened by the less dense surrounding plasma halo, whereas radiation emitted in the axial direction is a superposition of the emissions from the hot dense central region of the pinch and the colder less dense peripheral plasma.

An analytical model is proposed that allows predicting the effect of an acoustic field on the phase equilibrium conditions of liquid continua. Under the conditions of an arbitrary ultrasonic wave, an equilibrium interaction value analogous to the effect on the phase state of a substance is determined with use of the incubation time criterion. As an example, improved phase diagrams are built for the state of water affected by ultrasonic waves with frequencies in the range 10–100 kHz.

The structural-temporal approach is used for analyzing the energy required for fracture. The behaviors of the threshold fracture energy in the impact of spherical and cylindrical particles against an elastic half-space are compared. It is shown that the threshold energy minimum can be attained using spherical particles. The plots of the dependence of the threshold energy on the impact duration and on the particle radius are constructed for the cases under investigation.

The possibility of detecting a weak desired signal passed through gas among signals propagating in the pipe wall when sounding the flow with clamp-on probes is demonstrated. The possibility of applying this method to measurement of gas flow rate in large-size pipelines is also shown.

Results are presented from measurements of the radiation spectra of the Z-pinch tungsten plasma produced during the implosion of cylindrical wire arrays with a linear mass of 200–400 μg/cm and an initial diameter of 12–20 mm at a current of ∼3 MA in the experiments performed at the Angara-5-1 facility. The radiation spectra in the photon energy range of 50–900 eV were recorded on a UF-4 X-ray film by using a spectrograph with a transmission grating. The radiation spectrum in the photon energy range of 1–3 keV was recorded using a crystalline panoramic spectrograph. A curtain shutter was used to protect the transmission grating from fast microparticles produced due to the erosion of high-voltage electrodes. The total radiation yield was measured with a thermocouple calorimeter. It is shown that most of the tungsten plasma radiation energy is emitted in the photon energy range of 80–300 eV. Measurements of the spectral intensity of pinch radiation with a spatial resolution along the pinch radius showed that the effective transverse diameter of the pinch did not exceed 2 mm, which agrees with independent current measurements of the pinch size. The results of measurements of the spectral intensity of pinch radiation were compared with calculations per-formed under the assumption of a stationary homogeneous plasma.

Results are presented from experimental studies of the spatial distribution of the density of matter in the central part of the discharge gap and the formation of the temporal profile of the X-ray power in the course of implosion of quasi-spherical wire arrays at discharge currents of up to 4 MA. The spatial distribution of the X-ray intensity in the central part of the discharge gap and the temporal profile of the X-ray power are used as implosion characteristics of quasi-spherical wire arrays. The quasi-spherical arrays were formed by the radial stretching of unstrained wires of initially cylindrical and conical wire arrays under the action of the electrostatic field. The temporal profile of the output X-ray pulse in the photon energy range of 0.1–1 keV is shown to depend on both the geometrical parameters of the quasi-spherical array and the longitudinal distribution of its mass. It is found that a 40% increase in the wire mass due to deposition of an additional mass in the equatorial region of a quasi-spherical array leads to a 15% increase in the average current radius of the pinch and a 30% decrease in the X-ray yield. Experiments with quasi-spherical arrays made of kapron fibers with deposited Al and Bi conducting layers were also carried out. It is demonstrated that application of such arrays makes it possible to control the profile and duration of the generated X-ray pulse by varying the mass, material, and location of the deposited layer. It is found that deposition of an additional mass in the form of a thin Bi stripe on tungsten wires near the cathode end of the array allows one to mitigate the influence of the cathode zipper effect on the pinch compression and formation of the X-ray pulse in tungsten arrays.

The self-demodulation of acoustic pulses in the near zone of an acoustic radiator is studied both theoretically and experimentally. In the experiment, the aforementioned nonlinear process is studied for three types of biological tissues.

A radiation foil bolometer intended for measuring radiation-energy fluxes and plasma flows in high-power pulsed plasma X-ray sources is studied. In the bolometer, the radiation or ion-flow energy is absorbed by a 13-μm-thick niobium foil preliminarily heated to T ≈ 1900 K by a quasi-constant current lasting 2 s. Radiation from the foil was fed through an 8-m-long light guide to a semiconductor photodetector. The sensitivity of the instrument obtained from the results of calibrations is 0.56 J/V cm2. The time resolution of this technique (∼2.5 μs) is determined by the foil heating time. In experiments with megaampere Z-pinches, the time resolution attained allows detection of the radiation energy independently of the energy of expanding plasma flows. In this case, the photoelectric effect from X-rays and the conductivity of expanding plasma do not affect the operation of the radiation bolometer. The working capacity of the bolometer was demonstrated at the Angara-5-1 facility in experiments with high-current Z-pinches with a radiation output energy of 50–100 kJ/pulse. The measurements performed have shown that the energy flux density of plasma expanding in the direction perpendicular to the pinch axis is at most 5% of the energy flux density of soft X-rays.

Transient processes associated with gas bubble excitation by ultrasonic pulses are investigated based on the numerical solution to the Rayleigh-Plesset equation. The results are used to consider ultrasonic methods of gas bubble detection and sizing in liquids and biological tissues on the basis of linear and nonlinear bubble properties. The possibility of frequency separation of signals received from bubbles with different sizes in the case of their pulsed excitation is experimentally demonstrated.

Results are presented from experimental and theoretical studies of the efficiency of using a CO2 laser to create a high-power source of 13- to 14-nm EUV radiation for lithography. For a laser intensity of ∼2 × 1011 W/cm2, a conversion efficiency of kEUV ≃ 1.5% was achieved on a plane solid Sn target. The calculated gas dynamics and population kinetics of Sn plasma ions agree qualitatively with experimental results.

The results of a study of a radiating Z-pinch with a profiled initial gas-density distribution over the z axis are presented. The gas distribution with the density maximum and transverse-size minimum at the discharge-gap center is formed by a pulsed gas valve with a specially designed nozzle. The parameters of X-ray radiation are measured for pinches formed in gaseous neon at currents of up to 200 kA. The experimentally selected gas density ensures the formation of a region with a typical size of less than 1 mm at the discharge-gap center. This region emits X-ray radiation in the keV photon-energy range in a time of less than 5 ns. Prospects for the development of an X-ray source based on this mechanism are discussed.

Results are presented from experimental studies and numerical simulations of three-dimensional dynamics of the plasma produced in the Angara-5-1 facility by the electrical implosion of conical wire arrays at currents of up to 3 MA. The arrays were made of 6-to 8-μm-diameter tungsten wires, the inclination angle of the generatrix with respect to the axis being from 15° to 42°. The results of two-dimensional MHD simulations are compared with experimental data. The formation dynamics of the plasma precursor is found to be different for cylindrical and conical arrays. As the cone angle increases, the duration of the X-ray pulse increases, while the height of the pinch radiating zone decreases.

A study is made of the Z-pinch plasma expansion after the current is switched off. Measurements were carried out in experiments on the implosion of tungsten wire arrays in the Angara-5-1 facility. It is found experimentally that, at a distance of 2 m from the pinch, the ion velocity in the expanding Z-pinch plasma is about (2.5–4.0) × 107 cm/s, which substantially exceeds the thermal velocity of tungsten ions. A model describing the plasma expansion process is proposed that is based on the ambipolar acceleration mechanism. The results of numerical simulations are compared with the experimental data.

Investigation of the influence of divalent metal cations on the induction of plasminogen catalytic activity by monoclonal antibody IV-Ic showed that the presence of metal cations in the reaction medium changes the induction by slowing down or accelerating the process. Ions of Zn(2+), Mn(2+), and Cu(2+) completely inhibit activation. Ions of Co(2+) and Ni(2+) decrease the rate of the first and second phases of the reaction more than 2 times. Ca(2+) ions do not have any effect on the activation rate. Ions of Mg(2+), Ba(2+), and Sr(2+) increase the rate of the first phase of the reaction by 1.5, 2.0, and 2.0 times and the rate of the second phase by 2.0, 3.8, and 4.7 times, correspondingly. Sr(2+) ions have the strongest stimulating effect on plasminogen activation by monoclonal antibody IV-Ic. Investigation of the dose dependent effect of Sr(2+) on the rate of plasminogen activation by monoclonal antibody IV-Ic showed stimulating effect of Sr(2+) at concentrations from 0.1 to 1.0 mM with half maximum at 0.6 mM. However, Sr(2+) ions do not affect amidolytic activity of plasmin and activation of plasminogen by streptokinase. Sr(2+) ions also do not affect monoclonal antibody IV-Ic binding to plasminogen. The effect of Sr(2+) is specific and mediated by the IV-Ic component. The presence of metal cations affects conformational changes in the process of active site formation. Metal cations also affect structure of the plasminogen molecule active site in the complex with monoclonal antibody IV-Ic and enzyme-substrate interaction. The effect of alpha(2)-antiplasmin on the induction of plasminogen catalytic activity by monoclonal antibody IV-Ic in range of concentrations from 5 to 30 nM has been studied. alpha(2)-Antiplasmin at concentration 30 nM almost completely inhibits induction of plasminogen catalytic activity by monoclonal antibody IV-Ic at the ratio plasminogen/alpha(2)-antiplasmin of 3 : 1. This can be explained by competition of alpha(2)-antiplasmin and monoclonal antibody IV-Ic for the lysine-binding sites of plasminogen and inhibition of the active center in activated complex plasminogen*-mAB IV-Ic. Divalent metal cations and alpha(2)-antiplasmin are important factors in induction of plasminogen catalytic activity by monoclonal antibody IV-Ic.

In the physics of the wire array implosion the amount of the substance left on the periphery of the initial wire array at the moment of final liner implosion is an essential factor. Estimates show that plasma with a small mass fraction (a few percent of the initial wire array mass) may shunt an appreciable current fraction which can result in changing output characteristics of implosion. The given paper reports the investigation into the plasma density distribution on the periphery of the initial wire array near the moment of final implosion.

Results are presented from experiments on the X-ray backlighting of the axial region of an imploding high-current multiwire liner. Backlighting was performed with the use of an X-pinch serving as a source of soft X-ray emission, which was recorded by pin diodes. The use of several filters with different passbands in front of the pin diodes allowed the interpretation of the results of measurements in experiments with cascade composite liners. The sensitivity of the diagnostics was ≈125 µg/cm2 for a plasma of high-Z elements (W) and ≈220 µg/cm2 for a plasma of low-Z elements (C, O, N) at a photon energy of the probing radiation of 1.0–1.5 keV. An advantage of the method is its high time resolution (≈1 ns) and the possibility of the separation in time of the emission bursts from Z-and X-pinches on the liner axis. The method does not impose restrictions on the pulse duration of the backlighting radiation source.

The features are studied of plasma production in the initial stage of implosion of hollow cylindrical wire arrays at electric-field growth rates of 1012 V/(cm s). The results are presented from the analysis of both UV emission from the wire plasma and the discharge parameters in the initial stage of the formation of a Z-pinch discharge. It is found that, a few nanoseconds after applying voltage to a tungsten wire array, a plasma shell arises on the wire surface and the array becomes a heterogeneous system consisting of metal wire cores and a plasma surrounding each wire (a plasma corona). As a result, the current switches from the wires to the plasma. A further heating and ionization of the wire material are due primarily to heat transfer from the plasma corona. A model describing the primary breakdown along the wires is created with allowance for the presence of low-Z impurities on the wire surface.

Prolonged plasma creation in heterogeneous liners, in which the liner substance is separated into two phase states (a hot plasma and a cold skeleton), is investigated both experimentally and theoretically. This situation is typical of multiwire, foam, and even gas liners in high-current high-voltage facilities. The main mechanisms governing the rate at which the plasma is created are investigated, and the simplest estimates of the creation rate are presented. It is found that, during prolonged plasma creation, the electric current flows through the entire cross section of the produced plasma shell, whose thickness is comparable with the liner radius; in other words, a current skin layer does not form. During compression, such a shell is fairly stable because of its relatively high resilience. It is shown that, under certain conditions, even a thick plasma shell can be highly compressed toward the discharge axis. A simplified numerical simulation of the compression of a plasma shell in a liner with prolonged plasma creation is employed in order to determine the conditions for achieving regimes of fairly compact and relatively stable radial compression of the shell.

A construction of an effective nonrenormalizable superpotential has been discussed within the approach of a four-dimensional heterotic superstring with free fermions on the world sheet. On the basis of N=2 superconformal theory, useful selection rules that take into account all global symmetries have been obtained within the formalism of covariant vertices and the ghost-picture-changing operation. The results have been applied to the model featuring the effective observable gauge group U(5)×U(3)H, which includes the non-Abelian horizontal group and which describes (3+1) generation. The full superpotential of the model up to sixth order inclusive has been obtained, and its coupling constants have been calculated. The quark-lepton mass spectrum of the model has been discussed with allowance for contributions from nonrenormalizable terms.

Experimental data on acoustic cavitation in cryogenic liquids are analyzed using a criterion based on the incubation time concept. An analogous approach was successfully used earlier for analyzing the cavitation resistance of degassed and sea water at constant temperature. The proposed criterion takes into account the change in the static cavitation threshold and incubation time upon an increase in temperature.

The results of spectral measurements of radiation from microsecond gas Z-pinch are presented. The pinch current is 250 kA with a rise time of 1 μs. At the maximum nitrogen-pinch compression, the radiation spectrum corresponds to the emission of helium-, lithium-, and beryllium-like ions. The spectral-intensity peak lies within the spectral range 15–25 nm, which corresponds to the 2s-3p transitions of Li-and Be-like ions and to higher-energy transitions of these ionization states (2s-4p, 2s-5p, and 2s-6p). The spectra are measured in the first, second, and third diffraction orders. The total yield of X rays measured by a thermocouple-based calorimeter was 45 J at a 2-kJ electric energy stored in the capacitor bank. The pinch-radiation intensity and the spectra obtained experimentally are compared to the results of two-dimensional simulation of the emitting-plasma plasma dynamics using the ZETA radiation-magnetic hydrodynamic code.

Time evolution of the X-ray spectrum of a lead ion plasma generated by CO2 laser pulses with an energy of 100 J and a duration of 15 ns was measured using an X-ray polychromator with six channels covering the quantum energy range from 180 to 1850 eV. The plasma temperature was determined by comparing the results of measurements with the calculated X-ray emission spectra. The electron temperature measured well agrees with the calculated data.