Small-angle X-ray scattering study of the structure of self-organized polymer matrices and formation of imbedded metal nanoparticles

The structures of self-organizing polymer matrices based on collapsed gels and polyoctadecylsiloxanes have been studied by the methods of conventional and anomalous X-ray small-angle scattering with the use of the laboratory and synchrotron sources of X-ray radiation. The process of formation of metal nanoparticles in such matrices is also studied, their size distributions are calculated, and the models of localization of these particles in the polymer matrices are suggested. It is shown that growth of metal particles is controlled by the structure of the polymer network and is limited by the dimensions of its cells. The electron-density profiles of polycondensed octadecylsiloxane matrices are also calculated.     

Electron and phonon effects in superconducting tunnel detectors of x-radiation

Nb/Al/AlO_x/Nb superconducting tunnel junctions were investigated in the role of x-ray detectors. Amplitude spectra of pulses arising upon irradiation of tunnel junctions of different sizes by ⁵⁵Mn x-radiation were recorded at a temperature T=1.4 K. We also analyzed the temporal shape of the pulses. We considered the influence of diffuse motion of nonequilibrium quasiparticles, the inverse tunneling effect, and exchange of 2Δ phonons between electrodes, on the characteristics of the tunnel detectors. It is shown that phonon processes can bring about changes in the amplitude, duration, and polarity of the signal. Fiz. Tverd. Tela (St. Petersburg) 41, 1168–1175 (July 1999)     

Model investigations of wave formation in solid ice cover from the motion of a submarine

Komsomol'sk-on-Amur. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 2, pp. 78–81, March–April, 1994.     

Some laws governing the disproportionation of ions in condensed media

The laws governing the variation of the activation energy and the rate constant of the disproportionation of ions as functions of their oxidation number, the principal quantum number, the number of electrons in the valence shell, the symmetry of the arrangement of the ligands and their nature, and the outer-sphere environment have been substantiated.Translated from Teoreticheskaya i Éksperimental/naya Khimiya, Vol. 26, No. 5, pp. 591–596, September–October, 1990.     

Kinetics of the reduction of water by activated aluminum powder

Experimental investigations of the kinetics of reduction of water when it is reacted with activated aluminum suggest that the mechanisms for the processes at low and high temperatures differ in the activation energy and the pre-exponential factor. This is explained on the basis of the theory we developed previously for electron transfers from the solid phase to antibonding orbitals of the H₂O via tunneling and activation mechanisms.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 31, No. 4, pp. 238–242, July–August, 1995.     

Neutron yields upon irradiation of thick targets by ions with energies below 1.75 MeV/Nucleon

The yields of neutrons produced in thick LiF, Be, C, Al, Al₂O₃, and Cu targets irradiated by Li, C, and N ions with energies below 1.75 MeV/nucleon are measured on the DC-60 cyclotron at the Institute of Nuclear Physics, Astana Branch, Kazakhstan. The experimental angular distributions of the neutron yields from the targets are measured and an empirical equation to describe the distributions is proposed. The measured neutron yields are compared with the figures calculated by the LISE++ program. The measured and predicted neutron yields in the reactions coincide to within a factor of 2.     

Effect of the viscosity properties of ICE on the deflection of an ICE sheet subjected to a moving load

Steady-state rectilinear motion of a load on an ice sheet modeled by a viscoelastic plate is considered. The viscoelastic properties of ice are described using the linear Maxwell and Kelvin-Voigt models and a generalized Maxwell-Kelvin model. Calculated vertical displacements and strains of the ice plate are compared with available experimental data. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 147–157, May–June, 2009.     

Numerical solution of the problem of the effect of a shock pulse on an ice sheet

A mathematical formulation of the problem is given. A method is proposed to determine the initial velocities of points of an ice sheet subjected to a point shock pulse. An example of calculation of ice-sheet deflections is considered. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 152–159, March–April, 2008.     

Synthesis and investigation of stable copper nanoparticle colloids

The synthesis of stable nanoparticle colloids by laser ablation of the copper target in water and fragmentation of Cu + CuO nanopowder with pulsed fiber laser irradiation with a wavelength of 1064 nm and pulse duration of 100 ns has been investigated experimentally. The influence of the technological parameters on the nanoparticle size and stability of the colloid has been studied. It has been shown that the laser ablation creates the CuO spherical nanoparticles. Subsequent fragmentation makes it possible to reduce the nanoparticle size in a colloid and to produce a stable colloidal solution from an aqueous suspension of Cu + CuO nanopowder.