Numerical solution of the problem of sound emission by a cylindrical piezoelectric vibrator excited by electric pulses

A numerical method is proposed to solve the nonstationary wave problem for a piezoelectric ceramic cylinder immersed in a liquid and excited by an electric signal. The method uses a finite-difference scheme constructed by the integro-interpolation method. A numerical experiment is conducted to analyze the transients in a thin-walled cylinder excited by a step electric pulse.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 61, pp. 30–37, 1987.     

Structure and Energy Studies of β-Diketonates. X. Molecular Structure of Sc(aa)3 According to Gas-Phase Electron Diffraction Data

Synchronous electron diffraction and mass spectrometric investigation of the saturated vapor of scandium tris-acetylacetonate was carried out. It was stated that at 155(5)°C the vapor contains only monomeric Sc(aa)₃ molecules, whose structural parameters r _a , r _g , and r were determined. The internuclear distances in the chelate ring were found to be r (Sc–O) = 2.076(4) , r (O–C) = 1.271(3) , r (C–C_r) = 1.386(4) . The coordination polyhedron ScO₆ has a nearly antiprism structure of D ₃ symmetry. The angle of rotation of the O–O–O trigonal faces relative to their position in a regular prism is 26.8(1.1)°.     

Study of small variations of troposphere parameters by the radioacoustic sounding method

We consider a method based on the study of signal amplitude and phase variations in the radioacoustic sounding (RAS) of the atmosphere for the diagnostics of dynamical and wave processes in the troposphere. We give experimental data on phase variations of the RAS signal from scan to scan in daytime and nighttime sessions. Variations of the signal phase with characteristic time greater than 40 min are likely due to the passage of internal gravity waves (IGW) through the sounding region. The experimental data are in good agreement with the results of computer simulation of IGW propagation. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 11, pp. 1355–1364, November, 1997.     

Mathematical models and numerical methods for stability analysis of materials subjected to radiation pulses

We consider problems in modeling the interaction between a solid body and radiation pulses having intensity of order 10⁹–10¹⁵ W/m². We construct one-dimensional mathematical models for radiative damage to materials on the basis of the theory of thermal erosion and the kinetic theory of stability.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 70, pp. 67–73, 1990.     

Molecular structure of tris(dipivaloylmethanato)lutetium(iii) studied by gas electron diffraction and ab initio and DFT calculations

Combined gas electron diffraction/mass spectrometry (GED/MS) was used to determine the molecular structure of tris(dipivaloylmethanato)lutetium(III), Lu(dpm)(3)(dpm = 2,2,6,6-tetramethyl-heptane-3,5-dionato). Up to about 520-570 K the vapour consisted only of molecules Lu(dpm)(3). The experimental data recorded at 408(5) K indicate that the molecules have D(3) symmetry. The bond distances (r(h1)) in the chelate ring are Lu-O 2.197(6) Angstrom, C-O 1.270(4) Angstrom and C-C 1.390(6) Angstrom . Theoretical computations at the HF and DFT levels with basis sets up to 6-311G* afford structures similar to those found experimentally, with a distorted LuO(6) antiprism.