Table of contents

Mass determination methods and their results for ten black holes in X-ray binary systems are summarised. A unified interpretation of the radial velocity and optical light curves allows one to reliably justify the close binary system model and to prove the correctness of determination of the optical star mass function f_v(m).The orbit plane inclination i can be estimated from an analysis of optical light curve of the system, which is due mainly to the ellipsoidal shape of the optical star (the so-called ellipticity effect). The component mass ratio q = m_x/m_v is obtained from information about the distance to the binary system as well as from data about rotational broadening of absorption lines in the spectrum of the optical star. These data allow one to obtain from the value of f_v(m) a reliable value of the black hole mass m_x or its low limit, as well as the optical star mass m_v. An independent estimate of the optical star mass m_v obtained from information about its spectral class and luminosity gives us test results. Additional test comes from information about the absence or presence of X-ray eclipses in the system. Effects of the non-zero dimension of the optical star, its pear-like shape, and X-ray heating on the absorption line profiles and the radial velocity curve are investigated. It is very significant that none of ten known massive (m_x > 3M) X-ray sources considered as black hole candidates is an X-ray pulsar or an X-ray burster of the first kind.

A review is given of crystallographic, magnetic and electric properties of lanthanum manganites and related materials with a giant magnetoresistance (GMR). An analysis of experimental data for partially substituted manganites shows that if the spontaneous magnetic moment is unsaturated, the material is being in a phase-separated ferro-antiferromagnetic state. One possible GMR mechanism consists in a change of such a state under the magnetic field. If the magnetic moment of these materials is saturated, they display a resistivity peak in the vicinity of the Curie point. It is caused by the interaction of the charge carriers with spatial fluctuations of the electric potential and local magnetization. Suppression of this peak by the magnetic field leads to a GMR in ferromagnetic conductors.

Being the source of light quanta in optoelectronic devices like semiconductor lasers and light-emitting diodes, radiation recombination processes are of great importance in the constituent semiconducting structures. The latter consist of thin epitaxial layers, and their radiative recombination efficiency depends on structural imperfections such as dislocations, usually acting as nonradiative recombination centres, and point defects. Since these imperfections usually have a nonuniform layer distribution, radiation characteristics are distributed inhomogeneously over the layers and small-scale structural elements. For such structures, therefore, cathodoluminescence scanning microscopy, controlling the microlevel distribution of radiation characteristics, is an irreplaceable research tool. The effective use of this technique requires a correct understanding of the radiation-producing processes occurring during the electron probe–semiconductor interaction. A knowledge of the potential and the information capacity of the method is essential.

Current hypotheses concerning the breaking of mirror symmetry in the bioorganic world are reviewed critically. Two interrelated aspects of the problem, matrix structured homochiral macromolecules and enantiospecific functions capable of keeping homochiral structures replicating, are discussed. Two basic approaches to symmetry breaking, namely evolutionary selection and asymmetric origin scenarios, are considered, whose underlying hypotheses are shown to be inherently inconsistent.

Depending on pressure–temperature conditions, fullerite crystals can transform as to the well-known carbon phases, graphite and diamond, and to new metastable crystalline and amorphous modifications. The mechanical properties, density and structural data of the latter are reviewed. It is concluded that the crystalline C₆₀ phases possess mechanical characteristics 2-3 times lower than that for the diamond; amorphous states of carbon with a large share of the sp³-configurations have mechanical properties close to those of the diamond. The analysis of current literature enables us to conclude that the diamond has the highest elastic moduli among the carbon materials studied up to date.

On April 23 and 25, 1996, the seminar "Mesoscopic and strongly correlated systems" was held at the P L Kapitza Institute for Physical Problems Russian Academy of Sciences. The talks presented were the following: (1) V D Kulakovskii (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka) 'Correlation effects in an electron-hole quantum-well magnetoplasma'; (2) Yu V Dubrovskii, VG Popov, E E Vdovin, Yu N Khanin, I A Larkin (Institute of Microelectronics Technology, Russian Academy of Sciences, Chernogolovka), T G Andersson, J Tordson (Chalmers University, Goteborg, Sweden), J-C Portal, D K Maude (High Magnetic Fields Laboratory, Grenoble, France) 'Tunnelling resonances in a single-barrier heterostructure'; (3) V E Kravtsov (L D Landau Institute of Theoretical Physics, Russian Academy of Sciences) 'Wave function multifractality and energy level statistics near the Anderson transition'; (4) G B Lesovik (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka), A L Fauchere, J Blatter (Institute of Theoretical Physics at ETH) 'Scattering matrix description of nonlinear transport in NS contacts'; (5) A Yu Kitaev (L D Landau Institute of Theoretical Physics, Russian Academy of Sciences) 'Quantum calculations'; (6) G Yu Logvenov, V A Oboznov, V V Ryazanov, A V Ustinov (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka) 'Vortex dynamics in one- and two-dimensional discrete Josephson structures'; (7) E S Soldatov, S P Gubin, A S Trifonov, V V Khanin, G B Khomutov S A Yakovenko (Physics Department of M V Lomonosov Moscow State University) 'Correlated electron tunnelling in a tunnelling cluster structure'; (8) V F Gantmakher, MV Golubkov, VN Zverev (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka) 'Superconducting response in highly resistive materials'; (9) VF Gantmakher, VN Zverev, VM Teplinskii (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka) 'Scaling relations in three-dimensional disordered superconductors'; (10) S A Gudoshnikov, O V Snigirev (Physics Department of M V Lomonosov Moscow State University) 'Scanning SQUID microscopes: design and applications' (11) S I Dorozhkin (Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka) 'Magneto-transport and magnetocapacitance of two-dimensional electronic systems in strong magnetic fields; the integer and fractional Hall effects, and the dielectric state'; et al.