Nanostructurization in X-ray amorphous organic substances of geological origin

The nanosized structures of natural X-ray amorphous organic substances were examined with the use of atomic-force microscopy. The supramolecular structure types and particle sizes of natural solid bitumens from asphaltites to high anthraxolites were determined. It was shown that the supramolecular structure is suitable as a diagnostic structural criterion for grouping and subgrouping natural solid bitumens. Specific features of the nanostructure of Baltic amber were determined.     

Stochastic Dynamics of Flexible Systems with Motion Limiters

This paper presents an asymptotic analysis of the stochastic impact dynamics for a flexible structure with a unilateral rigid stop. The structure is modelled as an m.d.f. system in which one of the masses (the base) impacts on the stop. Assuming weak dissipation and weak coupling between the base and the secondary structure, we achieve the model reduction. Examination of the reduced model by the stochastic averaging method allows estimation of the statistical properties of the vibro-impact motion. A relationship between the responses of the secondary and primary structures is derived.     

Dependence of the enthalpies of formation of glycylglycinate complexes of nickel(II) on the composition of a mixed water-dimethylsulfoxide solvent

The heat effects of the complexation reactions of nickel(II) with a glycylglycinate ion in a water-dimethylsulfoxide solvent in a range of compositions of 0.00–0.60 molar parts of dimethylsulfoxide (DMSO) (an ionic strength of 0.1 was maintained using sodium perchlorate) were determined by means of calorimetry at 298.15 K. It is established that the exothermicity of complexation reactions rises by the first two steps and falls upon the addition of a third glycylglycinate anion with an increase in the concentration of DMSO. It is shown that the formation of mono- and bis-glycylglycinate complexes of nickel(II) in a water-DMSO solvent is determined mostly by the enthalpic contribution. It is concluded that the formation of tris-ligand complexes is more associated with the entropic contribution.     

Characteristics of Heteroassociates in the System Dimethylformamide-Water,According to Data of <Superscript>1</Superscript>H NMR Relaxation,Refractometry, Densimetry,and Acoustic Spectroscopy

The dimethylformamide-water system was studied by proton spin-spin relaxation (296 K) and refractometry (298 K), and the results in combination with published densimetric data (293 K) and data on the sound velocities (293 K) were used to simulate the associative equilibria. A consistent scheme of heteroassociative equilibria in the dimethylformamide-water system was suggested. The compositions of the heteroassociates were determined, and their stability constants (in the mole fraction scale), relaxation efficiency coefficients, limiting refractive indices, limiting sound velocities, and limiting densities were calculated.     

A study of the adsorption and surface properties of KSKG silica gel by gas chromatography

The adsorption properties of commercial wide-pore KSKG silica gel with respect to n-alkanes and their derivatives, the molecules of which possess different electron-donor and electron-acceptor properties, were studied by gas chromatography. The adsorption isotherms were used to determine the heats of adsorption, differential molar Helmholtz energies, and contributions of dispersion and specific (acid-base or donor-acceptor) interactions to these energies. The electron-donor and electron-acceptor characteristics of extremely hydroxylated silica gel surface were estimated. The electron-acceptor properties of the surface of KSKG were found to be much stronger than its electron-donor properties.     

Influence of the Inhomogeneous Surface Relief on the Magnetic and Magnetoelastic Properties of Amorphous Iron-Based Metal Alloys

The influence of the inhomogeneous surface relief on the magnetic and magnetoelastic properties of films, wires, and strips manufactured from amorphous iron-based metal alloys is investigated. It is demonstrated that the inhomogeneous surface relief is one of the main factors determining the magnetic and magnetoelastic properties of amorphous iron-based metal alloys. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 32–39, July, 2005.     

Nonstationary energy localization vs conventional stationary localization in weakly coupled nonlinear oscillators

In this paper we study the effect of nonstationary energy localization in a nonlinear conservative resonant system of two weakly coupled oscillators. This effect is alternative to the well-known stationary energy localization associated with the existence of localized normal modes and resulting from a local topological transformation of the phase portraits of the system. In this work we show that nonstationary energy localization results from a global transformation of the phase portrait. A key to solving the problem is the introduction of the concept of limiting phase trajectories (LPTs) corresponding to maximum possible energy exchange between the oscillators. We present two scenarios of nonstationary energy localization under the condition of 1:1 resonance. It is demonstrated that the conditions of nonstationary localization determine the conditions of efficient targeted energy transfer in a generating dynamical system. A possible extension to multi-particle systems is briefly discussed.