Waveforms in additional components of elastic bulk waves

Additional components in displacements of elastic wave fields are those which vanish in the case of propagation of homogeneous plane waves. For P-waves in a homogeneous isotropic solid, these are transverse components. Waveforms in additional components in simple models of non-time-harmonic elastic wave propagation with plane wavefronts are analyzed. It is demonstrated that the models based on homogeneous waves with a transverse structure and on inhomogeneous waves show a qualitative difference. Bibliography: 20 titles. Dedicated to V. M. Babich on the occasion of his 75th birthday Published in Zapiski Nauchnykh Seminarov POMI, Vol. 332, 2006, pp. 90–98.     

Asymptotics of an autoresonance soliton

Phase locking is studied in a one-dimensional medium under the action of an external force with slowly changing frequency. In a typical situation, the phase locking is described by a nonstationary nonlinear Schr¨odinger equation with external force. For large values of the time variable, the leading term of a space-localized growing asymptotic solution with soliton profile in the main order is constructed. It turned out that a time-growing asymptotic solution can be obtained for an external excitation with decreasing amplitude. Necessary growth conditions are deduced for such a solution in the presence of dissipation.     

Molecular dynamics simulation of deformation and fracture of graphene under uniaxial tension

The paper reports on molecular dynamics simulation of deformation and fracture of graphene under uniaxial tension. Dependences of Young’s modulus, critical force and fracture strain on the strain rate, temperature and angle between the tension direction and the graphene lattice are derived. The effect of defects on fracture of graphene is studied.     

Structure and energy of formation of β- and γ-cyclodextrin complexes with amino acid enantiomers

The interaction between cyclodextrins (CyD), β-CyD, and γ-CyD, and the L- and D-optical isomers of several amino acids (Ala, Leu, His, Phe) are calculated using DFT. It is found that the L-forms of the investigated amino acids bond more strongly to CyD, due to the different numbers of hydrogen bonds that form. The structures of the resulting complexes are analyzed.     

Gas chromatographic investigation of adsorption equilibria on graphitized thermal carbon black

Summary Retention volumes and heats of adsorption at low surface coverages of graphitized thermal carbon black (GTCB) for C₆–C₁₄ aromatic hydrocarbons have been determined. The dependence of heats of adsorption of these molecules on their structure and the number of carbon atoms in the molecule have been investigated. Substitution in the ring in methylbenzenes is not equivalent to the lengthening of the side-chain in the isomers of n-alkylbenzenes and gives rise to a much greater increase in the retention volumes and heats of adsorption.     

Point-like source solutions in modified gravity with a critical acceleration

We consider equations of modified gravity with critical accelerations and find its solutions for the point-like source by suggesting the appropriate symmetry of metrics in empty space-time.     

Modeling the crystallization of a Ti–Al nanoparticle by the molecular dynamics method

Crystallization of the Ti–Al intermetallide in the process of cooling from a melt at a constant volume has been simulated numerically using the molecular dynamics method.     

Phase Diagram of an Ethylene Glycol–Hexamethylphosphorotriamide System

The phase diagram of an ethylene glycol (EG)–hexamethylphosphorotriamide (HMPT) system is studied over two wide temperature intervals (+25°С…?90°С…+40°С) and (?150°С…+40°С) by means of differential scanning calorimetry using INTERTECH DSC Q100 and METTLER TA4000 DSC instruments (Switzerland) in the DSC30 mode with variable cooling/heating rates. Substantial overcooling of the liquid phase, a glass transition, and different types of interaction are observed in the system. No thermal effects are observed in intermediate range of concentrations during the slow cooling/heating processes, and the system remains liquid until the glass transition. The presence of such a metastable phase is attributed to a sharp rise in the viscosity of the system due to different kinds of interaction between the components. HMPT: 2EG and HMPT: EG compounds with crystallization temperatures of +5 and ?0.5°С, respectively, are observed upon rapid cooling and slow heating. Changes in enthalpy are calculated for all of the observed thermal effects. The distinction from the phase diagram of H₂O–HMFT (literary data) is explained by the difference in the interactions between system components and by the structural differences between EG and H₂O.     

Synthesis and electrochemical properties of lithium-vanadium bronze

Original method for synthesis of a lithium-vanadium bronze was developed. The method includes mechanical activation of a mixture of metavanadic acid and lithium carbonate in the course of a plastic flow under twisting.     

Dependence of the volume and viscosity of naphthalene-ethanol-octane solutions on composition at 298 K

The solubility of naphthalene in ethanol-octane mixtures was measured by the isothermal saturation method. The solution densities were determined and the partial and apparent molar volumes of naphthalene were calculated. The viscosity was measured with an Ubbelohde viscosimeter with a suspended level. All measurements were performed at 298.15 K. The results were discussed based on interactions in solution.