Reactions of platinum nitrile complexes with cyclotriphosphazenes containing pyridylalkylamino groups

Reactions of platinum(II) and platinum(IV) nitrile complexes with polydentate ligands, such as pentaphenoxy(2-pyridylmethylamino)cyclotriphosphazene, pentaphenoxy(3-pyridylmethylamino)cyclotriphosphazene, and pentaphenoxy(2-pyridylethylamino)cyclotriphosphazene, were studied. Platinum(IV) is reduced to platinum(II) upon complex formation; the pyridine and alkylamine nitrogen atoms coordinate to platinum(II) to form chelate rings. The compounds obtained were characterized by ¹H and ³¹P NMR and IR spectroscopy, FAB mass spectrometry, and other methods.     

Comparative Study of Intercalation of Zero-Valent Silver into the Cellulose Matrix by Raster and Transmission Microscopy

Diffusion-reduction interaction between microcrystalline cellulose and aqueous solution of AgNO₃ was studied in the absence (taking into account the reducing properties of cellulose) and in the presence of specific reductants. The resulting intercalates of cellulose and zero-valent silver were examined by raster and transmission electron microscopy. The morphological changes in cellulose after intercalation of silver nanoclusters as well as the nanocluster size distribution in the cellulose matrix were characterized.     

Comparative analysis and the coverage intervals of hair rare metal content in two Russian industrial centres

The existing data provide information on hair essential and toxic trace element content, whereas data on ultra-trace and rare elements are scarce. Therefore, the primary aim of the current study was to estimate hair levels and reference values of hair rare metal content using IUPAC recommendations in 2593 occupationally non-exposed adults living in Moscow and Novosibirsk (1900 women and 693 men). Hair Ag, Au, Ga, Ge, La, Rb, Tl, W and Zr content was assessed by inductively coupled plasma mass spectrometry with NexION 300D. Women were characterised by significantly higher hair Ag and Au levels than men, whereas men had increased La, Rb, Tl, W and Zr content as compared to women. Moscow inhabitants were characterised by significantly higher hair Au and Ge, and lower hair Ga, La, Rb, Tl, W and Zr content as compared to the ones from Novosibirsk. The coverage intervals of Ag, Au, Ga, Ge, La, Rb, Tl, W and Zr content in hair of the general sample of examinees calculated in accordance with IUPAC recommendations were 0.0278–0.2994, 0.0159–0.1812, 0.0062–0.0348, 0.0022–0.0066, 0.0023–0.0205, 0.0226–0.2083, 0.0002–0.0008, 0.0022–0.0120 and 0.0389–0.3521 μg/g, respectively. The obtained data indicate that both gender and geographical location affect hair rare metal content in adults.     

Evolution of the glow of an aerogel irradiated with a high-power pulse electron beam

The evolution of the glow of the energy-release zone in porous transparent aerogel, with a density of 0.03–0.25 g/cm³, which is irradiated by a high-power pulse electron beam, is studied experimentally. In addition to a fast (τ≤τ_beam) and a luminescent (τ≈10⁻⁶ s) glow components, a slow glow component (τ≈2×10⁻⁵ s) has been revealed. The appearance of this slow component is associated with an aerogel rarefaction wave and its destruction (cracking) arising after its isochoric bulk heating by electron radiation, which may occur due to an electrostatic field induced under irradiation. The discovered glow is utilized to visually determine the current position of the rarefaction wave front. The sound velocity measured as a function of the density of SiO₂ aerogels with porosities of 10–100 allowed us to experimentally determine the percolation parameter of the aerogel equation of state.     

Computer modeling of the dynamics of high-velocity impact and accompanying physical phenomena

Some results of mathematical modeling of high-velocity collisions of solid deformable bodies are presented. A model is presented of a porous elastoplastic medium whose matrix undergoes a polymorphic phase transition during deformation, and approaches to the calculation of dynamical failure are examined. Finite-difference methods for solving boundary-value problems are briefly reviewed. The interaction of projectiles, having different shape, with different targets (semiinfinite, two-layer, separated) is investigated and the process of spall failure in porous media and media undergoing a polymorphic phase transition is examined on the basis of mathematical modeling.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 5–48, August, 1992.     

Electron spin-lattice relaxation in layered cuprates and fullerides

A new technique of measuring extremely short electron spin-lattice relaxation times T₁～10^?6–10^?10 sec is developed and applied to study some oxide high-T_c materials, related compounds and fullerides RbC₆₀.     

Study of a converging short pressure pulse generated in a cylindrical polymer shell by an electron beam

This paper presents experimental and theoretical results from an investigation of the excitation and propagation of converging pressure waves in cylindrical shells made of polymethyl methacrylate (PMMA) producing spalling phenomena in the inner surface of the shell. It is found that fracture of the inner surface of a cylindrical shell requires a greater load as compared to the fracture of the rear side of a planar plate of the same material. The reasons for the observed phenomena are analyzed. The experimental results are compared with the results of a numerical simulation that takes into account phenomena occurring in the nonlinear region of elastoplastic deformation of polymer materials used as a base and in composite materials. Zh. Tekh. Fiz. 67, 88–94 (January 1997)     

Some special features of the transition to chaos in the self-modulation of surface spin waves

The results of experimental investigations of the transition from regular to stochastic self-modulation of intense surface spin waves are presented. It is found that the transition to chaos follows the scenario of a sequence of period-doubling bifurcations. The fractal dimensions and the Kolmogorov entropy are determined for different regimes. The experiments are performed on an apparatus consisting of a microwave oscillator with a spin-wave delay line in the feedback circuit. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 4, 243–246 (25 August 1997)