Lattice-supported surface solitons in nonlocal nonlinear media

We reveal that lattice interfaces imprinted in nonlocal nonlinear media support surface solitons that do not exist in other similar settings, including interfaces of local and nonlocal uniform materials. We show the impact of nonlocality on the domains of existence and stability of the surface solitons, focusing on new types of dipole solitons residing partially inside the optical lattice. We find that such solitons feature strongly asymmetric shapes and that they are stable in large parts of their existence domain.     

Alkoxylation and hydration of camphene in the presence of acid catalysts

The alkoxylation of camphene in the presence of various acid catalysts is studied. Alkylisobornyl ethers are obtained in high yields if the heteropolyacidsH ₄ SiW ₁₂O₄₀ andH ₃ PW ₁₂O₄₀ are used as the catalysts. The mechanism of the acid-catalyzed hydration of camphene in aqueous-alcohol solutions is examined. Nizhegorod State Technical University, 603000, Nizhnii Novgorod, ul. Minina, 24, fax (8312) 41 76 62; OAO “Lesosibirskii Rosin-Extraction Plant,” 663131, Krasnoyarsk Territory. Lesosibirsk-4, ul. Privokzalnaya, 2 fax (39145) 2 26 01. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 598–603, September–October, 1999.     

On the finite axiomatizability of varieties of commutative unary algebras

In this paper, it is proved that every variety of commutative unary algebras of a finite signature has a finite basis of identities.     

Dependence of radio emission from mercury on the structure and morphology of its outer layers

We present the results of a theoretical study of the dependence of radio emission from Mercury at wavelengths 0.3–76.8 cm on the structure and composition of its outer layer. Employing different models for the structure of this layer, we show that the radiative component of the heat flux strongly influences the effective temperature and its spectral characteristics. Using the two-stratum model, we demonstrate that account of morphological inhomogeneity over the depth of the outer layer is crucial for interpreting the data on radio emission from Mercury measured with high resolution over the planet’s surface. The obtained results may be useful for comparing experimental data with theory to determine the physical characteristics of the upper cover of Mercury. The results of this paper were partially reported at the XXVII Radio Astronomical Conference (St. Petersburg, November 10–14, 1997) [1]. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 3, pp. 203–214, March 1999.     

13C NMR spectra of the aminoglycoside antibiotics streptomycin and dihydrostreptomycin. Complete assignment of the signals

On the basis of the results of a study of the dependence of the chemical shifts of the¹³C NMR spectra streptomycin and dihydrostreptomycin over a wide pH range (from 1.0 to 10.0) and a comparison with the spectrum of streptidine in an acid medium, a complete assignment of the spectra of the antibiotics investigated has been made. The optimum pH values of solutions at which the clearest separation of the resonance signals in the spectra of streptomycin and dihydrostreptomycin have been determined (pH 1.0–7.0 and pH ≤ 8.6, respectively). All-Union Scientific-Research Institute of Antibiotics, Moscow. I. M. Sechinov 1st Moscow Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 695–700, September–October, 1980.     

Stress-intensity coefficients in an infinite plate with a crack in a nonuniform steady field

The stress-strain state around the end of a crack ¦x¦<, y=0 in the elastic plane (x, y) is considered for arbitrary given loads acting on the periphery of the crack and constant load at infinity. At the same time, there is a plane thermalstress state due to a steady heat flux parallel to the considered plane. An analytical expression is found for the stress-intensity coefficients in the given conditions, generalizing the case previously considered. A series of examples is given on the calculation of the intensity coefficients of purely temperature stresses in specific conditions of the thermal state of the elastic body. The results obtained may be used in constructing a theory of the time dependence of the strength in the gross failure of polymer materials.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 7–13, March, 1979.     

A new escape channel for ultracold neutrons in traps

A surprising new escape channel for ultracold neutrons (UCNs) in traps was reported recently. It could be relevant to the long-standing puzzle of the “too high” loss rate of UCNs from traps, which has yet to be completely understood and eliminated. In the present work we positively identify the new phenomenon and investigate it in detail. The escape of UCNs from traps is due to rare events in which their energy undergoes a small increase (∼10⁻⁷ eV). The reason for such an energy gain and its impact on the physics of UCN storage is still to be investigated. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 3, 175–180 (10 August 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

On the possibility of suppression of the self-frequency shift of the cnoidal waves in the medium with delayed nonlinear response by bandwidth-limited amplification

We both theoretically and numerically investigate conditions of the stable balance between competing processes of the Raman self-frequency shift and bandwidth-limited amplification of the periodical cnoidal waves. The dependencies of the initial wave form-factor and frequency shift necessary for the stable balance on the parameter describing degree of localisation of the wave energy are presented.     

Soliton mobility in nonlocal optical lattices

We address the impact of nonlocality in the physical features exhibited by solitons supported by Kerr-type nonlinear media with an imprinted optical lattice. We discover that the nonlocality of the nonlinear response can profoundly affect the soliton mobility, hence all the related phenomena. Such behavior manifests itself in significant reductions of the Peierls-Nabarro potential with an increase in the degree of nonlocality, a result that opens the rare possibility in nature of almost radiationless propagation of highly localized solitons across the lattice.     

Soliton spiraling in optically induced rotating Bessel lattices

We address soliton spiraling in optical lattices induced by multiple coherent Bessel beams and show that the dynamic nature of such lattices makes it possible for them to drag different soliton structures, setting them into rotation. We can control the rotation rate by varying the topological charges of lattice-inducing Bessel beams.