Oligonucleotides containing arylacetylene residues: Synthesis and post-synthetic modification via [3+2] cycloaddition

The synthesis of a phosphoramidite reagent for 5′-modification of oligonucleotides by introducing an arylacetylene residue has been described. Using the reaction with 3-(perylen-3-yl)propyl azide as an example, it was shown that the acetylene derivatives of oligonucleotides synthesized using this reagent undergo Cu^I-catalyzed [3+2] dipolar cycloaddition. Fluorescent conjugates were obtained in high yields and characterized by mass spectra. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1220–1226, July, 2006.     

Structural characterization of self-organized nanostructures

Self-organized nano-objects fabricated in different semiconductor systems are currently at the focus of scientific interest because of their unique electronic properties. Transmission electron microscopy and high-resolution electron microscopy have been used to study the InAs quantum dots grown by molecular-beam epitaxy (MBE) on GaAs and InP substrates. Optimal imaging conditions for visualization of quantum dots were established. Size, shape, and stability of the equilibrium island arrays were analyzed with respect to the growth conditions. Both decrease and increase of the As pressure compared to the optimal value were shown to destroy the regular arrangement of the islands. Energy benefit due to the strain relaxation in the InAs islands is likely to be the driving force for their formation. Fiz. Tverd. Tela (St. Petersburg) 40, 849–851 (May 1998) Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor.     

Porous Structure of Activated Carbon Fibers

The dependence of the microporous structure of activated carbon fibers on the carbonization temperature of hydrate-cellulose fibers was studied by BET, TVFMP, and Horvath and Kawazoe techniques and methods of the nonlocal density functional theory. The surface energy distribution function was obtained, together with the micropore size distribution curves. It was shown that the effective micropore sizes calculated by the TVFMP method are close to the maximum of the distribution function found in terms of the theory of the density functional.     

Hall effect in La0.67−x CexSr0.33MnO3

An experimental study of the Hall effect and of magnetoresistance in polycrystalline La_0.67−x Ce_xSr_0.33MnO₃ samples (x=0, 0.07) is reported. It is shown that the normal Hall coefficient reverses sign at T ₀=360 K in both samples and that metallic conduction occurs for T<T ₀, while for T>T ₀ the conduction is by mechanisms operative in disordered materials. It has been established that doping with cerium brings about an increase in the metallic phase of the normal and anomalous Hall coefficients. A qualitative interpretation of the observed features is given. Fiz. Tverd. Tela (St. Petersburg) 40, 2085–2088 (November 1998)     

Thermal blooming of variable-radius beams in an approximation of small-perturbation theory

A general solution of the equations of geometrical optics is obtained that describes the weak thermal blooming of optical beams whose radius in the absence of blooming varies according to a known law (in particular, these are focused or defocused beams).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 2, pp. 135–142, February, 1993.     

A Discrete Analog of Euler's Summation Formula

In this paper, we prove a discrete analog of Euler's summation formula. The difference from the classical Euler formula is in that the derivatives are replaced by finite differences and the integrals by finite sums. Instead of Bernoulli numbers and Bernoulli polynomials, special numbers P_n and special polynomials P_n(x) introduced by Korobov in 1996 appear in the formula.     

Properties of subspaces of the space of affine functions

Conditions are presented for weak (strong) convergence, in the entire space A(x), of a sequence of positive operators to a fixed operator S on the basis of its weak (strong) convergence to S in a subspace. The criterion of Bauer's simplex is presented.Translated from Matematicheskie Zametki, Vol. 17, No. 2, pp. 307–318, February, 1975.In conclusion the author expresses his deep gratitude to Yu. A. Shashkin for his many valuable remarks.     

Optical methods of laser radar field processing

The book describes modern methods of receiving laser signals, viz., by interferometry, by nonlinear optics, by laser amplification, and by heterodyne mixing. The theory of these methods is considered as applied to the problem of laser radars. Investigated in detail are features such as the resolving power of interferometry and nonlinear-optics method, the efficiency of parametric conversion of laser signals, the sensitivity of laser amplifiers, and problems of optimal heterodyne detection. Methods of speckle interferometry and adaptive optics are described. The book is aimed at a large circle of scientists and engineers active in the problem of recording of laser signals, as well as to students in advanced courses of the corresponding specialties.N. D. Ustinov — General Editor.Translated from Metody Obrabotki Opticheskikh Polei v Lazernoi Lokatsii, pp. 3–269, 1983.