Unoccupied Electron States of Ultrathin Films of Thiophene–Phenylene Cooligomers on the Surface of Polycrystalline Gold

Physics of the Solid State - Unoccupied electronic states in the energy range from 5 to 20 eV above the Fermi level have been studied in ultrathin films of dimethyl-substituted...     

Theoretical investigation of the angular-momentum dependence of the mean fission lifetime of excited nuclei

Physics of Atomic Nuclei - Mean fission lifetimes of nuclei excited to energies of 80 to 400 MeV were recently measured at the GANIL accelerator by the crystal-blocking technique. Those experiments...     

Creation of laser-plasma spherical clouds by means of bilateral radiation

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 30, No. 6, pp. 62–66, November–December, 1989.     

Characteristic features of cyclotrimerization of perfluoroalkyl- and perfluorooxaalkylacetylenes

Cyclotrimerization of perfluoroalkyl- and perfluorooxaalkylacetylenes has been studied under various conditions. A scheme of the reaction mechanim has been suggested.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1789–1792, October, 1994.     

Measurement of slow motions in solids with strong dipole interaction using multipulse sequence

A single scan NMR multipulse sequence has been proposed to study slow motions in solids with strong dipole interactions. Calculations of the solid echo decay time in the cases of internal motions and rigid lattice have been made and compared with the experimental data obtained in polycristalline cyclohexane and in fluorite single crystals.     

Influence of electromagnetic fluctuations on the resonant tunneling of electrons

We have considered the influence of electromagnetic fluctuations on electron tunneling via one non-degenerate resonant level, the problem that is relevant for electron transport through quantum dots in the Coulomb blockade regime. We show that the overall effect of the fluctuations depends on whether the electron bands in external electrodes are empty or filled. In the empty band case, depending on the relation between the tunneling rate Γ and characteristic frequency Ω of the fluctuations, the field either simply shifts the conductance peak (for rapid tunneling, Γ Ω) or broadens it (for Γ Ω). In the latter case, the system can be in three different regimes for different values of the coupling g between electrons and the field. Increasing interaction strength in the region g < 1 leads to gradual suppression of the conductance peak at the bare energy of the resonant level ε₀, while at g 1 it leads to the formation of a new peak of width at the energy ε₀ + E_cis a charging energy. For intermediate values of g the conductance is non-vanishing in the entire energy range from ε₀ to ε₀ + E_c. For filled bands the problem is essentially multi-electron in character. One consequence of this is that, in contrast to the situation with the empty band, the fluctuations of the resonant level do not suppress conductance at resonance for g < 1. At g> 1 a Coulomb gap appears in the position of the resonant level as a function of its bare energy which leads to suppression of conductance.     

Encryption and decryption of information in chaotic communication systems governed by delay-differential equations

We consider different ways for encryption and decryption of information in communication systems using chaotic signal of a time-delay system as a carrier. A method is proposed for extracting a hidden message in the case when the parameters of the chaotic transmitter are a priori unknown. For different configurations of the transmitter the procedure of information signal extraction from the transmitted signal is demonstrated using numerical data produced by nonlinear mixing of the chaotic signal of the Mackey–Glass system and frequency-modulated harmonic signal.     

Invariant cubature formulas of degree eleven which contain the Laplace operator

For the integral over the n-dimensional space with a radially symmetric weight function, two cubature formulas of degree eleven which are invariant under the group of hyperoctahedron are constructed. The formulas for the cubature sum contain the value of the Laplacian of the integrand at the point O(0, 0, ..., 0). Examples of approximate values of the parameters in these formulas are given.