Growth of 1-Periodic Graphs

A new class of graphs is introduced: 1-periodic graphs. A problem on the form of the growth of these graphs is stated. For certain classes of graphs, a self-similar growth in the form of a polygon is proved. Certain general conjectures on the form of the growth are stated. Bibliography: 1 title.     

Production of superfine fibers by the electrospinning method

Weakly conducting fluid flows in an electric field in the presence of phase interfaces are investigated theoretically and experimentally. The object of the investigation is an axisymmetric jet. The analysis is carried out within the framework of electrohydrodynamics (EHD) with allowance for surface charge transfer on mobile interfaces. The jet shape is calculated at large distances from the outflow point. The theoretical and experimental data are compared for Newtonian and polymeric fluids.     

Synthesis of New 4,4a-Dihydroxanthones via [4+2]-Cycloaddition Reaction

Russian Journal of General Chemistry - The effect of electronic properties of substituents in the reactants on the [4+2]-cycloaddition of 3-vinyl-chromen-4-ones (dienes) and N-vinylpyrrolidines...     

Inverse problem in the layer-by-layer growth model

The problem of finding structural features of growing structures for which a specified growth shape is allowable is considered within the model of layer-by-layer growth of tilings or packings and the generalization of this model to connectivity graphs. In particular, the problem of revealing growth shapes that are impossible for periodic structures is solved.     

Efficient time integration in multiplicative inelasticity

In Shutov et al. (Comput Methods Appl Mech Eng 265:213–225, 2013), the numerical time integration of a famous large strain model of Maxwell fluid type has been considered. The underlying model is based on the multiplicative decomposition of the deformation gradient and includes a Neo-Hookean hyperelasticity relation as well as an incompressible viscous flow rule. Shutov et al. presented a time stepping algorithm for implicit time integration of the inelastic flow rule, which is based on Euler backward time discretisation, prevents error accumulation and is iteration free. In this contribution, the basic idea of the this approach is applied to more general models of multiplicative viscoelasticity. Here, extended hyperelastic relations including general functions of the first principal invariant of deformation tensors are regarded. An efficient time stepping algorithm is derived, where only one scalar equation for one scalar unknown has to be solved within every time step. The approach is applied to a specific viscoelastic model. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Morphology of integral (structural) polymer foams

The survey deals with the fundamental morphological parameters of integral (structural) polymer foams, which have a specific structure: a cellular core that gradually turns into a solid skin. Attempts are made to evaluate the effect and the contribution of the main parameters (the core, the skin, and the intermediate zone) on the strength properties of these foams. Further problems in the morphology of integral foams are discussed.     

Nanostructure Evolution of Oxide Dispersion Strengthened Steels under Fe Ion Irradiation at 350°C

Physics of Atomic Nuclei - Improved mechanical properties of oxide dispersion strengthened (ODS) steels, the advanced materials for the reactor core, are due to the high density of uniformly...     

Parametric amplification at low-frequency pumping and generation of four-mode entangled states

We show that parametric amplification at low-frequency pumping can be implemented in aperiodic nonlinear photonic crystals. In this process, the intensities of the waves with frequencies higher than the pumping frequency increase with increase in the interaction length as in the case of the standard process of parametric amplification at high-frequency pumping. The process under consideration includes a nondegenerate parametric down-conversion followed by two parametric up-conversions in the same pumping wave. As a result, generation at four new frequencies arises. Quantum analysis of the process demonstrates the presence of entanglement in the states of four modes. Talk presented at the oral issue of J. Russ. Laser Res. dedicated to the memory of Professor Vladimir A. Isakov, Professor Alexander S. Shumovsky, and Professor Andrei V. Vinogradov held in Moscow February 21–22, 2008.     

Study of the energy release region of a heavy-ion flux in nanomaterials by X-ray spectroscopy of multicharged ions

X-ray spectroscopic data are reported on the state of a silicon aerogel medium (SiO₂) irradiated by a Ni ion flux with an energy of 4.7 MeV/nucleon. Radiation from the electron transitions to the K shell in multicharged Si ions is detected with spatial resolution along the direction of the beam propagation in the medium. Calculations performed for the ionization state and population of the levels excited in the silicon atoms of the target provide the estimate T_e = 70–120 eV for the medium electron temperature in the ion tack region. Two-dimensional hydrodynamic calculations provide the estimate T_e = 60–116 eV for the same conditions and densities of 0.5–2.5 g/cm³ of the excited target medium.     

Second experiment at VASSILISSA separator on the synthesis of the element 112

The upgraded separator VASSILISSA was used to confirm results of previous experiments on the synthesis of the heavy isotopes of the element 112 obtained in complete-fusion reactions of ⁴⁸Ca and ²³⁸U. An additional reason was the non-observation of any events in the same reaction studied with the BGS separator at Berkeley. Limits of for the atomic mass number of the observed spontaneously fissioning isotope were measured. The obtained results on the decay mode, half-life and production cross-section are in agreement with those obtained in our first experiment.Received: 10 June 2003, Revised: 29 July 2003, Published online: 2 December 2003PACS: 23.60. + e decay - 25.70.-z Low and intermediate energy heavy-ion reactions - 25.85.Ca Spontaneous fission - 27.90. + b