Some general questions of fast-electron transport

An inverse problem of fast-electron transport in a dielectric is proposed. This problem consists of determining the field distribution in the dielectric from the measured variations of functionals caused by an electric field within the dielectric. A method for solving the inverse problem on the basis of the general theory of variations in transport functionals is examined. It is shown that the distribution of the information functionals throughout the sample is required in order to determine the appropriate set of sources and functionals. The condition for the independence of the information functionals is obtained. It is also shown that if the variations of the transport functionals are measured and if the information functionals are known, the inverse problem of determining the field distribution reduces to the solution of a system of algebraic equations. Equations are derived for determining the value of the information required to calculate the information functionals.Translated from Izvestiya VUZ. Fizika, No. 6, pp. 25–29, June, 1973.     

Resonance size effect in relaxation of space charges in polymethyl methacrylate

The paper reports the results of measurements of the space-time properties of space charges in polymethyl methacrylate (PMMA) disks after a high-energy injection of electrons. Investigations by four independent methods (i.e., the through-probing, current, electrostatic, and sectioning methods) reveal that, first, the charge distribution is radially inhomogeneous regardless of the small ratio of the specimen thickness to diameter (1/10 to 1/30) and, second, space-time relaxation of charges occurs in a singular manner at diameters of 32, 65, and 130 mm.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 62–67, July, 1979.     

Action of the irregular Hecke operator of index p on the theta-series of a quadratic form

Let F be a positive-definite integral even matrix of even order. For an arbitrary prime number p and natural n one obtains an explicit expression for the image of the theta series of genus n of the matrix F, under the action of an irregular Hecke operator with index p, in the form of a linear combination of theta series.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 144, pp. 68–71, 1985.     

Mechanical and nonlinear elastic characteristics of polycrystalline AMg6 aluminum alloy and <Emphasis Type="Italic">n</Emphasis>-AMg6/C<Subscript>60</Subscript> nanocomposite

The influence of nanostructuring on the mechanical and nonlinear elastic characteristics of polycrystalline AMg6 aluminum alloy and n-AMg6/C₆₀ nanocomposite has been experimentally studied. The independent second- and third-order elastic coefficients are measured via the ultrasonic method. The thir-dorder elastic coefficients have been evaluated via the Tearstone–Bragger approach from the experimentally established velocities of shear and longitudinal bulk acoustic waves as the functions of the uniaxial compression in the studied samples. The nonlinear elastic properties are examined via the spectral acoustic technique in AMg6 aluminum alloy and n-AMg6/C₆₀ nanocomposite, and the nonlinear acoustic parameters are determined.     

Liquid-vapor equilibrium in the system acetone-methanol-<Emphasis Type="Italic">N</Emphasis>-butylpyridinium hexafluorophosphate

The liquid-vapor equilibrium in the system acetone-methanol-N-butylpyridinium hexafluorophosphate was studied at 313.15 K.     

Phenomenological model of the accumulation of a space charge by high-energy injection of electrons in high-resistivity materials

The assumption of a constant ratio of the density of free carriers to the total carrier density in the process of electron injection is used to develop a phenomenological model of the accumulation of a space charge by high-energy injection. Use is made of the concept of a quasi-Fermi level in the case of an exponential distribution of trap energies.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 96–98, May, 1980.     

Measurement of the probability of atomic capture and depolarization of negative muons in high-temperature superconductors

The possibility of investigating high-temperature superconductors (HTSC) by the μSR method with negative muons is discussed in the paper. The results of measurement of the probability of negative muon capture by oxygen and residual polarization of muons in the 1s-state of oxygen in some HTSC at room temperature are reported.