Sound field variations caused by intense internal waves in a shallow sea with a weak thermocline

Results of an experiment on investigating the fluctuations of a sound signal with a frequency of 295 Hz on a stationary 32-km-long acoustic path in a shallow sea are presented. Hydrological conditions on the path were characterized by the presence of a weak thermocline and a frequent occurrence of intense internal wave trains. The space-time characteristics of these internal waves were measured in detail. Experimental evidence of the repetition of the forms of internal solitons in the variations of the amplitude and phase of an acoustic signal was obtained.     

Explicit Formulas for Generalized Action–Angle Variables in a Neighborhood of an Isotropic Torus and Their Application

Different versions of the Darboux–Weinstein theorem guarantee the existence of action–angle-type variables and the harmonic-oscillator variables in a neighborhood of isotropic tori in the phase space. The procedure for constructing these variables is reduced to solving a rather complicated system of partial differential equations. We show that this system can be integrated in quadratures, which permits reducing the problem of constructing these variables to solving a system of quadratic equations. We discuss several applications of this purely geometric fact in problems of classical and quantum mechanics.     

Aspects of alpha-particle scattering and structure of the nuclear surface

The interaction of α particles above 5 MeV with a 2s-1d target is dominated by resonances. It cannot be described only in terms of a mean-field one-body potential. An analysis of the elastic α-particle scattering by ²⁸Si encourages the comprehension of the resonance states to be mainly fragments of a mixed-parity band. In the present article, the angular distributions of particles scattered by ³²S are analyzed in terms of such bands. The analysis of new data from an experiment made at Florida State University reveals the existence of states that do not belong to the above bands. This follows from a coupled-channel analysis of the elastic and inelastic (2⁺) cross sections. An α-particle structure at the nuclear surface is suggested.     

A Constraint Programming Approach to Extract the Maximum Number of Non-Overlapping Test Forms

This paper introduces a novel approach for extracting the maximum number of non-overlapping test forms from a large collection of overlapping test sections assembled from a given item bank. The approach involves solving maximum set packing problems (MSPs). A branch-and-bound MSP algorithm is developed along with techniques adapted from constraint programming to estimate lower and upper bounds on the optimal MSP solution. The algorithm is general and can be applied in other applications including combinatorial auctions. The results of computer simulations and experiments with an operational item bank are presented. An erratum to this article is available at .     

Quasiclassical spectral series of an electron in an axialsymmetric electric field (construction of asymptotics)

Using the Maslov techniques, we construct quasiclassical asymptotics for the Dirac operator in an axial-symmetric focusing electric field, which correspond in the h O limit to two types of classical motion of an electron: a helical motion with small oscillations around an equilibrium orbit, and a motion along an arbitrary (open) orbit in the plane perpendicular to the axis of the particle's drift.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 67–72, September, 1989.     

Geminal systems. 50. Solvolysis of 1-tosyloxy-Δ2-1,2,3-triazoline-5,5-dicarboxylate esters and the structure of the solvolysis product,O-tosyl-N-α,α-bis(ethoxycarbonyl)-β-methoxyethylhydroxylamine

Solvolysis of 1-tosyloxy-²-1,2,3-triazoline-5,5-dicarboxylic acid esters (1) occurs via elimination of N₂ and leads predominantly to N--hydroxylethyl-O-tosylhydroxylamines (II), whose structure was determined unequivocally by x-ray structural analysis. The mechanism of solvolysis of triazolines (I) is discussed, along with the structural characteristics and stabilization factors of the O-tosylhydroxylamine products (II).For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1820–1827, August, 1990.