Mass-spectrometric thermal analysis of polymers based on furyl alcohol

Mass-spectrometric thermal analysis of samples of furan polymers obtained by heating furyl alcohol in a closed volume at 200 °C, 250 °C and 300 °C permitted determination of the qualitative composition of the gas products evolved from the polymers upon non-isothermal temperature increase from 20 to 1200 °C. The degree of unsaturation of the samples was evaluated quantitatively. The main features of the formation, degradation, structurization and carbonization of furan polymers were considered.     

On vertex parts of p-adic Feynman amplitudes

We reduce the calculation of the vertex parts of p-adic Feynman amplitudes to a recursive procedure for evaluating singular parts of certain integrals. We propose an algorithm for calculating these integrals in the general form. As an example, we consider vertex parts of amplitudes in the ? ⁴ theory.     

Concentrators of deformations and fracture of plastic bodies

An approach to the investigation of shape discontinuity regions as strain concentrators is proposed. The near-concentrator strain fields are determined on the basis of the theory of ideal rigid-plastic body; under the condition of plane deformation, their determination is reduced to integration of ordinary differential equations. The deformation as a function of the location of the plastic region and its shape evolution in the process of plastic flow is studied. The plastic flow is demonstrated to be not unique (within the framework of solution completeness). A deformation criterion for the choice of the preferred plastic flow is suggested. The fracture of a V-notched strip is considered. On the basis of the solutions obtained, an approach to the investigation of the fracture processes for more complicated models is formulated.     

Finite-dimensional parametric problems in inverse problems of astrophysics

Two inverse problems of astrophysics are considered: determining the velocity of the moon by the method of stellar eclipses (occultations of stars by the moon) and determining the geometrical parameters of double systems from light curve observations. These methods produce basic stellar data with accuracy several orders of magnitude higher than standard methods. The initial problems are ill-posed. A stable solution is obtained by finite-dimensional parametrization.Translated from Metody Matematicheskogo Modelirovaniya, Avtomatizatsiya Obrabotki Nablyudenii i Ikh Primeneniya, pp. 23–39, 1986.