Identity period and thermal expansion coefficient for rare-earth hexaborides at temperatures of 5–320 K

The temperature dependences of the lattice spacing and thermal expansion coefficient for five hexaborides MB₆ (M=Ce, Pr, Nd, Gd, and Tb) are experimentally investigated.     

Neutron diffraction study of ordering in the γ-phase of the aluminium-magnesium system

In the present work neutron diffraction study is made of the ordering effekt within the whole region of the existence of the γ-phase of the Al-Mg system. Depending on thermal treatment conditions, the order coefficient S varies from 0.15 to 0.7 for compounds containing 59 and 60 at.% Mg at temperatures ∼330 and below 150°C, respectively. – At decreased annealing temperatures the ordinate of the highest ordering is shown to approach the composition which may be approximately characterized as Al₂Mg₃. The temperature increase results in the decrease of the ordering degree, and the ordinate of the highest ordering displaces to the composition which may be expressed as Al₁₂Mg₁₇. – Kurnakov's point is determined which is lying at ∼330°C for the composition containing 59 at.% Mg.     

Mobius Transforms for Linear Ordinary Differential Equations

The Mobius transforms for linear ordinary differential equations of the second order are examined. It is shown that this transform has some quasi-isospectral properties. Solutions of the Heun equation with one apparent singularity are constructed. Bibliography: 15 titles. __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 308, 2004, pp. 67–88.     

Polyethylene with improved environmental stress cracking resistance

The stress cracking resistance of low-pressure polyethylene can be improved by introducing finely dispersed mineral additives (TiO₂, SiO₂, Al₂O₃ · SiO₂) and surface-active agents (anthranilic, adipic, and sebacic acids; mannitol). The amounts needed to effectively increase the cracking resistance without detriment to the principal physicomechanical and other characteristics of the material have been determined.Mekhanika Polimerov, Vol. 4, No. 1, pp. 67–71, 1968Communication V of the series "Modification of the Structure and Properties of Polyolefins."     

Formation of ceramic solid solutions in a SrTiO<Subscript>3</Subscript>-BiScO<Subscript>3</Subscript> system

X-ray structural, X-ray phase, and dilatometric analyses were used to explore specific features of the formation of solid solutions in the (1 − x)SrTiO₃−xBiScO₃ system with x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5. It was found that the synthesis of solid solutions from the initial Bi₂O₃, Sc₂O₃, TiO₂, and SrCO₃ components is accompanied by a considerable increase in the linear dimensions of the samples, depending on their composition. Solid solutions with x > 0.1 are formed through intermediate phases (Sr₅Bi₆O₁₄ at x = 0.2; Sr_0.78Bi_2.22O₄ at x = 0.3; and Sr_2.25Bi_6.75O_12.38 at x = 0.4 and 0.5). It was shown that the samples with x = 0.2, 0.3, 0.4, and 0.5 have two phases: one with a cubic Pm3m structure and one with a tetragonal I4/mcm structure.