Experimental equation of state of the shape memory alloy Ti50Ni48Fe2 AT 0-8 GPa and 298 K

The influence of hydrostatic pressures (up to 8 GPa) at 298 K on the pressure curves of the volume and volume elastic modulus of the B2 phase of Ti₅₀Ni₄₈Fe₂ single crystals is investigated by an ultrasonic pulse-phase technique. It is proposed on analysis of the results that the alloy undergoes a B2→R martensitic, transition at 4.0–5.4 GPa. It is shown that the universal equation of state accurately describes the pressure dependence of volume over the entire pressure range. Institute of Strength Physics and Materials Science, Siberian Division, Russian Academy of Sciences. Institute of High-Pressure Physics, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 48–53, August, 1997.     

Gas-filled position-sensitive detectors of thermal neutrons at the Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences

The manufacturing line for the development and fabrication of position-sensitive detectors of thermal neutrons has been organized at the Petersburg Nuclear Physics Institute of the Russian Academy of Sciences. Three detectors with sensitive regions 300 × 170 (prototype), 200 × 200, and 300 × 300 mm in size have been constructed to date. The detectors represent multiwire proportional chambers with cathode data readout to a delay line. The devices are filled with the ³He/CF₄ gas mixture. These detectors are intended for modernizing the detector systems of the Vector and Membrana-2 diffractometers (VVR-M reactor, Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences, Gatchina, Russia).     

The role of excited species in UV-laser materials ablation

UV-laser ablation is described in terms of a two-level system in which the excitation energy is dissipated via stimulated emission, thermal relaxation, and activated desorption of excited species. For thermal relaxation times t _T>10^–9 s and E* E (activation energies for excited-state and ground-state species) the model predicts high ablation rates at moderate surface temperatures, typically below 2000° C.On leave from General Physics Institute, Russian Academy of Sciences, 117942 Moscow, RussiaOn leave from Institute of Applied Physics, Russian Academy of Sciences, 603600 Nizhnii Novgorod, RussiaOn leave from L.D. Landau Theoretical Physics Institute, Russian Academy of Sciences, 142432 Chernogolovka, Moscow region, Russia     

Features of evolution of the substructure in the creep of dispersion-hardened nickel

A study is made of the laws governing high-temperature creep and the evolution of the substructure in dispersion-hardened alloy Ni — 3 vol. % HfO₂ during its free annealing and creep. The polygonized substructure was formed in the alloy prior to annealing. An analysis is made of structural transformations at different structural levels and the mechanism of high-temperature creep in the alloy. Institute of the Physics of Strength and Materials Science, Siberian Branch of the Russian Academy of Sciences. All-Republic Engineering-Technical Center, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 83–89, March, 1998.     

Inductive-capacitive source with electrically exploded interruptor working into a capacitive load

Pulsed charging of a capacitance C_l from an LC circuit with a fast exploding-wire current interruptor is investigated by physical modeling and magnetohydrodynamic calculations. It is shown that the efficiency of energy transfer to the load is highest in the matched-explosion mode h_e/h₀=1. The energy density injected into the conductor by the time C_l is connected should be equal to the sublimation energy of the metal. With these and other defining conditions, the voltage U_l across the load is given naturally by the capacitance ratio, U_l/U₀=K=0.73(C/C_l). An overvoltage K=4–6.6 was actually obtained at an energy-transfer efficiency of ≅0.5. Institute of Heavy-Current Electronics, Siberian Division, Russian Academy of Sciences, and Institute of Electrophysics, Ural Division, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 45–51, December, 1995.     

Premartensitic and martensitic transformations in Ti49Ni51 single crystal: Ageing effect

The influence of isochronous annealing on the phase composition, long-range atomic-order parameter S in the B2 phase, premartensitic structure, and martensitic transformation sequence and temperatures in a Ti₄₉Ni₅₁ single crystal was studied by X-ray and neutron-diffraction. Ageing the test alloy was found to bring about concurrent changes in the type of the intermediate shear structure involved and in the sequence of martensitic transormations in the premartensitic temperature range studied. The increase in the order parameter for the B2 phase was most pronounced in passing from the zonal stage of ageing to the growth stage of the Ti₃Ni₄ precipitates, as revealed by X-ray diffraction. No apparent correlation between the type of the premartensitic structure, R-transformation temperature, and order parameter variations was observed. At the same time, the martensite start temperature into the B19′ phase was directly proportional to variations in S. Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences. Institute of Physics of Metals, Urals Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 64–70, July, 1999.     

Experimental observations of the stepped Cu-atom ionization in the active medium of a Cu laser

An optogalvanic effect in a pulsed copper-vapor laser is discovered and investigated. It is found that the generalized deexcitation rate constant of the resonance level to the ionization state of the active medium is <σv>∼ (3±1)·10⁻⁷ cm³·s⁻¹. An optothermal effect caused by the hysteresis of the optogalvanic phenomenon is found experimentally. The feasibility of measuring the stepped ionization constants of resonance and metastable states for a number of metal atoms in a pulse-discharge plasma is discussed. Institute of Physics of Semiconductors of the Siberian Branch of the Russian Academy of Sciences; Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences; Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences; Tomsk State University. Translated from Izvestiya Vysshikh Uchebhykh Zavedenii, Fizika, No. 8, pp. 57–62, August, 1999.     

On the possibilities of studying supernova neutrinos at Baksan

We consider the possibilities of studying a supernova collapse neutrino burst at Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) using the proposed 5-kt target-mass liquid scintillation spectrometer. Attention is given to the influence of mixing angle ? ₁₃ on the expected rates and spectra of neutrino events.     

New Magneto-Optical Effect in Co-Doped CuGeO3

We report the anomalous effect of the polarization dependence of electron paramagnetic resonance absorption in CuGeO₃ doped with 2% of Co. While the resonance line of Cu²⁺ chains is independent of the microwave polarization in the Faraday geometry, the resonant mode of Co impurity exhibits a strong polarization dependence for all directions of the external magnetic field. Possible reasons of such behavior are discussed. Authors' address: Alexey V. Semeno, Department of Low-Temperature and Cryogenic Engineering, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov ulitsa 38, Moscow 119991, Russian Federation     

Study of the hadronic component of extensive air showers at the Carpet-2 EAS array

A method for the detection of hadrons with a muon detector at the Carpet-2 EAS array (Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences) has been described. Events induced by cosmic-ray hadrons have a signature that makes it possible to reliably distinguish them from muons. The characteristics of the hadronic component of extensive air showers with N _e ≥ 10⁵ have been presented.     

Shirshov Oceanology Institute of the Russian Academy of Sciences and the Russian Acoustical Society invite specialists to the XI Brekhovskikh’s Workshop on Ocean Acoustics and the XVII Session of the Russian Acoustical Society dedicated to the memory of Academician L.M. Brekhovskikh

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Shirshov Oceanology Institute of the Russian Academy of Sciences and the Russian Acoustical Society invite specialists to the XI Brekhovskikh’s Workshop on Ocean Acoustics and the XVII Session of the Russian Acoustical Society dedicated to the memory of Academician L.M. Brekhovskikh     

High-pressure pulsed CO2 lasers

This paper presents a large body of data allowing one to determine the energy, time, and spectral characteristics of high-pressure pulsed CO₂ lasers over wide ranges of parameters. Institute of High-Current Electronics, Siberian Division of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 19–28, April, 2000.     

Electric dipole echo in solid solutions

A theory of microwave electric dipole echo in solid solutions is formulated in the example of (KBr)_1–x(KCN)_x. The behavior of the echo is attributed to tunneling CN^– molecules, which are treated as analogs of two-level systems in glasses. A concentration-dependent density of states of the two-level system is used in the calculations. The difference between the behavior of the echo signal in solid solutions and the behavior of the echo in glasses and spin systems is indicated. New echo signals associated with asymmetry of the double-well potential are found.Branch of the Institute of Solid-State and Semiconductor Physics, Academy of Sciences of Belarus, Vitebsk. Physicotechnical Institute, Kazan Science Center, Russian Academy of Sciences, Kazan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 49–58, July, 1993.     

Modeling of a pump discharge for chemical non-chain-reaction HF lasers

A model of a pump discharge for a chemicalHF laser in aNe/SF ₆/C₂H₆ gaseous mixture excited with a self-maintained discharge is described. The results of numerical modeling are presented. It is shown that the density of positive and negative ions in the current maximum of such discharges exceeds the electron density by two orders of magnitude. Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 63–66, August, 1999.     

The role of excited species in UV-laser materials ablation

The stability of a planar surface upon pulsed UV-laser irradiation is studied with special emphasis on polymer ablation. Here, we consider a two-level system in which the excitation energy is dissipated via stimulated emission, non-radiative transitions, and activated desorption of excited species. With thermal relaxation times t _T10^–10 s the ablation front turns out to become stable. This could explain the smooth surfaces obtained after pulsed UV-laser ablation of pure and stress free organic polymers. The situation is quite different for materials, for example metals, where fast thermal relaxation of the excitation energy within times, typically, t _T<10^–11 s, gives rise to instabilities which result in surface roughening.On leave from the Institute of General Physics, Russian Academy of Sciences, 117942 Moscow, RussiaOn leave from the Institute of Applied Physics, Russian Academy of Sciences, 603600 Nishnii Novgorod, Russia     

High-power high-pressure pulsed CO2 lasers

The results of investigations and development of high-pressureCO ₂ lasers are considered. It is shown that the high-pressure active medium allows radiation pulses to be formed with smooth tuning of frequency and duration over wide ranges. Data on small-size wide-apertureCO ₂ lasers with an output pulse energy up to 5 kJ are presented. Institute of High-Current Electronics of the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 74–77, August, 1999.     

Jubilee Scientific Conference of the Division of Combustion and Explosion of Semenov Institute of Chemical Physics of the Russian Academy of Sciences

Jubilee Scientific Conference of the Division of Combustion and Explosion

Jubilee Scientific Conference of the Division of Combustion and Explosion of Semenov Institute of Chemical Physics of the Russian Academy of Sciences     

Powerful pulsed electrophysical transformers from the Institute of High-Current Electronics,Siberian Branch of the Russian Academy of Sciences

Problems in the creation and exploitation of powerful pulsed electrophysical transformers, developed at the Institute of High-Current Electronics, Siberian Branch of the Russian Academy of Sciences, are discussed. The power of the largest installations is 2.5·10¹² W (pulsed). The small size, the outside location of the main components requiring maintenance, and the absence of large volumes of transformer oil make the pulsed transformers competitive with pulsed voltage generators. Institute of High-Current Electronics, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 58–66, December, 1995.     

Static multipole polarizability of atoms and ions in the Thomas-Fermi model

A method based on the Thomas-Fermi model for the electrostatic potential is proposed to calculate the multipole polarizabilities α _K of atoms and ions. In the case of highly charged ions an equation having a simple analytical form is derived. The dipole α₁ and quadrupole α₂ polarizabilities of atoms and ions with more than half-filled electron shells are calculated. Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva, Lebedev Physics Institute, Russian Academy of Sciences, Moscow, Vol. 195, pp. 179–194, 1989.