Practical implementation of multilevel quantum cryptography

The physical principles of a quantum key distribution protocol using four-level optical systems are discussed. Quantum information is encoded into polarization states created by frequency-nondegenerate spontaneous parametric down-conversion in collinear geometry. In the scheme under analysis, the required nonorthogonal states are generated in a single nonlinear crystal. All states in the selected basis are measured deterministically. The results of initial experiments on transformation of the basis polarization states of a four-level optical system are discussed.     

Calculation of the rupture life of mechanical rubber goods

The stress-strain relation for an aging material is obtained from an analysis of a four-element model of a viscoelastic body with variable coefficients. In this formulation the problem of calculating the rupture life is divided into four steps: a) solution of the boundary-value problem of the theory of elasticity of an incompressible material; b) calculation of the stationary thermal field; c) solution of the rheological equation at the danger point; d) solution of the criterial equation for the local fracture time. An example of the calculation of the high-temperature rupture life of a rubber cord under constant load is given. The agreement with experiment is satisfactory.Riga Polytechnic Institute. Translated from Mekhanika Polimerov, No. 1, pp. 91–95, January–February, 1976.     

Reaction of Indium with Tricarbonylcyclopentadienyl-molybdenum(II) and -tungsten(II) Chlorides

The reactions of indium with tricarbonylcyclopentadienyl-molybdenum(II) and -tungsten(II) chlorides in donor solvents result in formation of compounds containing Mo-In and W-In bonds. The formalkinetic features of the metal oxidation with ⁵-C₅H₅Mo(CO)₃Cl in dimethylformamide were studied.     

Lipids, Lipophilic Components, and Biologically Active Fractions of Viburnum opulus L. Seeds

Methyl and triterpenyl fatty-acid esters and triterpenic acids are isolated and identified from seeds ofViburnum opulus(Caprifoliaceae). The biological activity of pigments and proteins is determined     

Reaction of perfluorinated vinyl ethers with diethylamine

Russian Journal of General Chemistry -     

Photolysis of 2-(Triorganostannyloxy)-3,6-di-tert-butyl-benzquinone-1,4 in Alkanes Solution

Abstract

Photolysis of 2-(trimethylstannyloxy)-3,6-di-tert-butyl-benzquinone-1,4 (I), 2-(triphenylstannyloxy)-3,6-di-tert-butyl-benzquinone-1,4 (II), and 2-(tribenzylstannyloxy)-3,6-di-tert-butyl-benzquinone-1,4 (III) by light with the wavelength 436 nm leads to the evolution of carbon mono- and dioxide and the formation of hydrocarbon radicals with their consequent recombination.

GRAPHICAL ABSTRACT     

Spike-burst synchronization in an ensemble of electrically coupled discrete model neurons

In this paper, we study the dynamics of a system of two model neurons interacting via the electrical synapse. Each neuron is described by a two-dimensional discontinuous map. A chaotic relaxational-type attractor, which corresponds to the spiking-bursting chaotic oscillations of neurons is shown to exist in a four-dimensional phase space. It is found that the dynamical mechanism of formation of chaotic bursts is based on a new phenomenon of generation of transient chaotic oscillations. It is demonstrated that transition from the chaotic-burst generation to the state of relative rest occurs with a certain time delay. A new characteristic which estimates the degree of synchronization of the spiking-bursting oscillations is introduced. The dependence of the synchronization degree on the strength of coupling of the ensemble elements is studied.     

Kinetics of heat-induced and photochemical transformations of quinonimines and their derivatives

Heat-induced transformations of N-[2,6-diisopropylphenyl]-3,5-di(tert-butyl)-, N-[2,6-diethylphenyl]-3,5-di(tert-butyl)-, and N-[2-methyl-6-ethylphenyl]-3,5-di(tert-butyl)-o-benzoquinonimines in nonane follow the first-order rate equation, whereas that of N-[2,5-di(tert-butyl)phenyl]-3,5-di(tert-butyl-o-benzoquinonimine obey the second-order rate equation. Kinetic parameters of these reactions have been determined. 4aH-Phenoxazine derivatives of quinonimines are intermediates of the heat-induced transformations following the first-order kinetics; under the irradiation with 405 nm light they undergo the ring opening to give the starting compounds with quantum yield close to unity.