Special Aspects of Microstructure,Deformation and Fracture of Bioinert Zirconium and Titanium-Niobium Alloys in Different Structural States

Russian Physics Journal - The characteristics of microstructure, deformation and fracture of Zr – 1 wt% Nb and Ti – 45 wt% Nb bioinert alloys in the coarse- and ultrafine-grained states...     

Computer simulation of the relation between mechanical behavior and structural evolution of oxide ceramics under dynamic loading

Computer simulation is used to investigate the deformation and damage processes taking place in brittle porous oxide ceramics under intense dynamic loading. The pore structure is shown to substantially affect the size of the fragments and the strength of the materials. In porous ceramics subjected to shock loading, deformation is localized in mesoscopic bands having characteristic orientations along, across, and at ∼45° to the direction of propagation of the shock wave front. The localized-deformation bands may be transformed into macroscopic cracks. A method is proposed for a theoretical estimation of the effective elastic moduli of ceramics with pore structure without resorting to well-known hypotheses for the relation between elastic moduli and porosity of the materials.     

Highly sensitive sensors of molecular compounds based on globular photonic crystals

It is shown that a highly sensitive sensor of molecular structures can be implemented based on the use of globular photonic crystals with a molecular compound introduced into their pores. The technique under development allows performing the spectral analysis of individual molecules in photonic crystal pores. In particular, these experiments showed the possibility of detecting extremely small amounts of molecules of the type of Rhodamine-6G dissolved in an aqueous medium at concentrations ??10^?7 g/cm³ (??10^?10 mol/ml).     

Investigation of the fusion-fission reaction 12C+208Pb

For the first time the cross section and angular distributions of fission fragments have been measured for the compound nucleus 220 Ra produced in the reaction 12 C+ 208 Pb at three energy values in the range from 0.5 to 8.0 r MeV below the fusion barrier calculated in terms of the Bass model. In the investigated energy range there is a plateau characterized by the relation W (180°)/ W (90°)=1.2 in the angular anisotropy of fission fragments.     

M p -groups not containing groups of quaternions

This paper continues the study of the class of Mp-groups introduced by V. P. Shunkov. We obtain a criterion of nonsimplicity of an infinite group which contains anMp-group and contains no group of quaternions. We also obtain a criterion for an infinite group to be an Mp-group.     

On Frobenius groups with noninvariant factor SL 2(3)

We obtain a nonsimplicity criterion of an infinite group containing an infinite class of Frobenius groups L _g = 〈a, g ⁻¹ ag〉 with complement SL ₂(3). __________ Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, No. 6, pp. 765–777, June, 2006.     

Phenomenological investigation of spectral effect of intermolecular interaction 1. Relation between intramolecular vibration characteristics and intermolecular properties of polyatomic molecules. theoretical discussion

Without considering any specific mechanism of intermolecular interaction, it is shown that the change in the vibrational spectrum of polyatomic molecules under the action of intermolecular forces can be reduced to a change of the power coefficients of the molecules. Formulas are obtained which permit the investigation of the dynamics of the molecules of liquids and solids. The shaping of the spectral line contour in the regions of both external and internal vibrations is considered from a single viewpoint which ultimately reduces to the fluctuation of the power coefficients.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 101–105, January, 1978.The author is profoundly grateful to Professor A. V. Sechkarev for attention to this work and valuable discussion.     

Gamma-ray multiplicities and fission modes in (208)Pb((18)O,f)

Two components in the M(gamma)(M) distribution were established in detailed measurements of mean gamma-ray multiplicities from fission fragments of (226)Th. For the first time in the M(gamma)(M) dependencies we were able to distinguish two components associated with primary and the final (after the neutron evaporation) fission fragments, and show that at the scission point M(gamma) is extremely sensitive to symmetric and asymmetric modes of fission. Theoretical calculations of the pre-scission shapes of the fissioning nuclei confirm our conclusions.