Scattering matrix approach to large-scale photonic crystal circuits

We propose a scattering matrix approach to the modeling of large-scale photonic crystal circuits and show that the transmission properties of complex circuits can be accurately calculated on the basis of scattering matrices of individual photonic crystal devices and waveguides that connect them. In addition, we show that functional devices such as waveguide bends generally exhibit a discontinuous frequency dependence in the phases associated with their complex reflection and transmission coefficients and emphasize its importance for the adequate modeling of photonic crystal circuits.     

Self-trapping and stable localized modes in nonlinear photonic crystals.

We predict the existence of stable nonlinear localized modes near the band edge of a two-dimensional reduced-symmetry photonic crystal with a Kerr nonlinearity. Employing the technique based on the Green function, we reveal a physical mechanism of the mode stabilization associated with the effective nonlinear dispersion and long-range interaction in the photonic crystals.     

Multi-component structure of nonlinear excitations in systems with length-scale competition

We investigate the properties of nonlinear excitations in different types of soliton carrying systems with long-range dispersive interactions. We show that length-scale competition in such systems, universally results in a multi-component structure of nonlinear excitations which may lead to a new type of multistability: coexistence of different nonlinear excitations at the same value of the spectral parameter (i.e., velocity in the case of anharmonic lattices or frequency in nonlinear Schr?dinger models). Received 31 August 2000 and Received in final form 14 December 2000     

Preparation of an adhesion-reducing agent for synthetic caoutchouc in a tubular turbulent apparatus

Results of a study of the fundamental aspects of preparation of an adhesion-reducing agent for synthetic caoutchouc, based on commercial calcium stearate, are presented. A method for preparing an adhesion-reducing agent in a turbulent apparatus is suggested. The method yields SKI-3 isoprene caoutchouc satisfying the requirements to the content of stearic acid, with the content of chlorine ionsa in wastewater diminished by a factor of 1.8.     

Stratification dynamics and the development of electrothermal instability at the wire explosion

The stratification dynamics at wire explosion of copper and nickel wires (25 and 50 μm) in air is studied under current dwell conditions. Experimental and theoretical data are presented for the stratification of a core due to electrothermal instability. The evolution of strata during the quasi-adiabatic expansion of the core is studied, and it is shown that the elongation of strata and their dynamics are well described in terms of a model of electrothermal instability for conductors with different diameters.     

Disperse Composition of Titanium–Magnesium Catalyst Particles and <Emphasis Type="Italic">trans</Emphasis>-1,4-Polyisoprene Granules in Short-Time Polymerization

The disperse composition of trans-1,4-polyisoprene granules and supported titatium–magnesium catalyst particles in the ultrarapid polymerization of isoprene within 0.1–0.7 s is studied. It is shown that within this period the alteration of external and internal fragmentations occurs between two fractions of polymer granules that are formed by 0.1 s of polymerization and already contain significantly fragmented catalyst particles. The correlation between these processes and molecular mass characteristics of trans-1,4-polyisoprene is investigated. It is found that the external fragmentation is accompanied by a decrease in the average molecular masses of the polymer, while the internal fragmentation leads to formation of a higher molecular mass trans-1,4-polyisoprene. As a result, the fraction of polymer granules with a diameter of 7.5 μm is formed by 0.7 s of polymerization and replication to high conversions is developed on their basis.     

Hydrodynamic effect on the heterogeneity of active sites of butadiene polymerization upon formation of titanium catalyst in situ

The effect of hydrodynamic conditions of the reaction mixture flow during formation of active sites sites of butadiene polymerization on their distribution by kinetic and stereospecific heterogeneity was studied. The enhanced intensity of the turbulent mixing at the stage of formation of active sites results in lowering of the number of types of active sites of chain propagation and the polydispersity coefficient with changes in stereoregular composition of polybutadiene.     

Solitons in anharmonic chains with ultra-long-range interatomic interactions

We study the influence of long-range interatomic interactions on the properties of supersonic pulse solitons in anharmonic chains. We show that in the case of ultra-long-range (e.g., screened Coulomb) interactions three different types of pulse solitons coexist in a certain velocity interval: one type is unstable but the two others are stable. The high-energy stable soliton is broad and can be described in the quasicontinuum approximation. But the low-energy stable soliton consists of two components, short-range and long-range ones, and can be considered as a bound state of these components.