High-voltage conductivity of α-RbAg4I5, α-KAg4I5, and α-KCu4I5 superionic conductors

It is found that the conductivity of RbAg₄I₅, KAg₄I₅, and KCu₄I₅ solid electrolytes in the ??-phase rises with the electric field strength and tends to a limit value in fields on the order of 1 MV/m. The high-voltage limit of conductivity exceeds the low-voltage one by 100% or more. The application of an intense electric pulse raises the conductivity of the electrolytes by 35%, and the activated state exhibits an anomalously long relaxation time.     

Study of an Electromagnetic Wave Transmission Line Based on Coupled Dielectric Resonators

Doklady Physics - An analog of an optical waveguide in the form of a chain of metallic nanoparticles has been investigated using modified cylindrical dielectric resonators in the microwave band....     

Random coloring method in the combinatorial problem of Erdős and Lovász

The work deals with a combinatorial problem of P. Erd?s and L. Lovász concerning simple hypergraphs. Let denote the minimum number of edges in an n‐uniform simple hypergraph with chromatic number at least . The main result of the work is a new asymptotic lower bound for . We prove that for large n and r satisfying the following inequality holds where . This bound improves previously known bounds for . The proof is based on a method of random coloring. We have also obtained results concerning colorings of h‐simple hypergraphs. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 2012     

Molecular dynamics investigation of the helical structure of smectic C*

The numerical simulation of the behavior of the molecules of the DOBAMBC liquid crystal by the molecular dynamics method allowed us to find the change of the the conformation of molecules as a function of temperature and to reveal the helical structures with various pitches in the smectic phase C*. These results explained the anomalous temperature dependences of the order parameter at the molecular level, as well as the optical second harmonic generation in the region of smectic A.     

Dielectric properties of liquid crystals in polycapillary matrices

This paper reports on the results of investigations into the dielectric properties of liquid crystals embedded in polycapillary matrices and describes a technique for their measurement. It has been revealed that the chemical structure of the rigid core and the length of mobile alkyl groups of liquid-crystal molecules of the alkylcyanobiphenyl group substantially affect the equilibrium configuration of the liquid-crystal director in capillaries. The reorientation of liquid-crystal molecules embedded in capillaries in the nematic phase under the influence of an external magnetic field has been investigated.     

Reconstruction of the distribution function of relaxation times for 7CB and 7OCB liquid crystals from dielectric spectra

A technique for reconstructing the distribution function of relaxation times from the dielectric spectra measured over a wide range of frequencies is proposed and tested using 7CB and 7OCB liquid crystals as examples. The objective function, which is the sum of the squares of the differences between the calculated and measured permittivities, is minimized with the Mathcad program package. It is demonstrated that, in the case of parallel orientation of the molecular director with respect to the polarization of the ac electric field, the distribution function of relaxation times is consistent with the Debye relaxation model; however, there are insignificant deviations in the short-time interval corresponding to the high-frequency portion of the dielectric spectrum. For perpendicular orientation of the director, the distribution function of relaxation times exhibits specific features that are most pronounced for the 7OCB liquid crystal and probably reflect intramolecular motions of the rigid core and fragments of the alkyl chain.