Thermal effect in phase-periodic electron transport in disordered mesoscopic normal metal/superconductor structures

We report measurements of the temperature dependence of the amplitude of phase-periodic conductance oscillations in disordered normal metal (Ag) structures, attached to a superconducting (Al) wire at two points. The amplitude of oscillations reaches its maximum at temperatureT ^*, when the Thouless energy is of the order ofk _B T. The results are in agreement with recent calculations by Nazarov and Stoof [Phys. Rev. Lett. 76 (1996) 823].     

Non smooth dynamics of mechanical systems with history term

Models involving maximal monotone term and history (delay) term are considered in a mathematical and numerical point of view.     

Non-coercive Linear Elliptic Problems

We study here some linear elliptic partial differential equations (with Dirichlet, Fourier or mixed boundary conditions), to which convection terms (first order perturbations) are added that entail the loss of the classical coercivity property. We prove the existence, uniqueness and regularity results for the solutions to these problems.     

Synthesis, structures, and properties of new thiophosphorylated fullerenopyrrolidines. First example of the Pishchimuka reaction in fullerene derivatives

The reactions of fullerene C₆₀ with thiophosphorylated mono-or dialdehydes and N-methylglycine in toluene afforded new thiophosphorylated fullerenopyrrolidines, including those containing the free aldehyde group. The purity and compositions of the reaction products were confirmed by MALDI-TOF mass spectrometry and HPLC. The structures of the reaction products were established by two-dimensional homo-and heterocorrelation NMR experi-ments. The properties of the products were studied by cyclic voltammetry and quantum chemical methods. The Pishchimuka rearrangement in thiophosphorylated derivatives of fullerenopyrrolidines was performed for the first time, and thiol esters of phosphonic acids of fullerenopyrrolidines were prepared. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 489–497, March, 2006.     

Relaxor properties and the mechanism of conduction in TlInS<Subscript>2</Subscript> crystals exposed to gamma irradiation

The density of states at the energy levels associated with radiation-induced defects, the localization length of a defect center, and the hopping distance of charge carriers are determined in a TlInS₂ crystal. It is demonstrated that, by varying the dose of gamma irradiation, it is possible to control the dielectric properties of ferroelectrics and to attain a stable relaxor state. In the temperature range of existence of this state, charge carriers execute tunneling from electron levels in the band gap through potential barriers created by an incommensurate superstructure of the TlInS₂ crystal.     

Nickel catalysts for the addition polymerization of norbornene and its derivatives and for their copolymerization with ethylene

The addition polymerization of norbornene and its derivatives has been carried out in the presence of a nickel complex or carboxylate and an electron acceptor to obtain amorphous polymers with bicyclic units. Norbornene copolymers with conjugated dienes or ethylene cannot be obtained with these catalysts because of rapid chain transfer reactions. Norbornene can be copolymerized with ethylene under mild conditions in the presence of nickel phosphorylide chelates without using any cocatalyst. In most cases, the backbone of the resulting copolymer consists of alternating comonomer units. The new catalysts allow ethylene to be copolymerized with norbornene derivatives containing ester substituents.     

Synthesis of pyridyl(trichloromethyl)carbinols under interphase-catalysis conditions

The corresponding pyridyl(trichloromethyl)carbinols were obtained by reactions of 2- and 3-formylpyridine and 6-methyl-2-formylpyridine with chloroform in the presence of aqueous or solid alkali and an interphase catalyst. It is shown that carrying out the reaction in a liquid-solid system is more efficient than in a liquid-liquid system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 46–49, January, 1990.     

On the analysis of coordinate-dependent diffusion

Coordinate-dependent diffusion in solids, in which case the probability of presence of a vacancy, φ, and the probability of migration, γ, depend on coordinate x is analyzed. The coordinate dependence of parameters φ and γ is shown to cause the drift component of the diffusion flux. In the presence of this component, the direction of atomic motion may coincide (enhanced diffusion) or not coincide (retarded diffusion and up-diffusion) with the direction of the diffusion component. The criteria of enhanced diffusion, retarded diffusion, and up-diffusion are established. These criteria are specified by the behavior of function F(x)=φ(x)/γ(x).     

Gibbs measures for the SOS model with four states on a Cayley tree

We analyze the SOS (solid-on-solid) model with spins 0, 1, 2, 3 on a Cayley tree of order k ≥ 1. We consider translation-invariant and periodic splitting Gibbs measures for this model. The majority of the constructed Gibbs measures are mirror symmetric. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 149, No. 1, pp. 18–31, October, 2006.