Total absorption method for nonuniform layer

The possibilities of using the total absorption method for plasma diagnosis are examined both in the case of weak and strong absorption and in the intermediate case. A formula is obtained for the last two cases by which the distribution of the concentration of atoms along the plasma radius can be determined. For diagnosis purposes the distribution along the line of sight of the width of the absorption line and the distribution along the plasma radius of the halfwidth of the thin layer line, which specifically can be found from the asymmetrical self-reversed lines, must be measured. The limits of the applicability of the method are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 105–109, May, 1977.     

Auditory stream segregation in monkey auditory cortex: effects of frequency separation, presentation rate, and tone duration

Auditory stream segregation refers to the organization of sequential sounds into "perceptual streams" reflecting individual environmental sound sources. In the present study, sequences of alternating high and low tones, "...ABAB...," similar to those used in psychoacoustic experiments on stream segregation, were presented to awake monkeys while neural activity was recorded in primary auditory cortex (A1). Tone frequency separation (AF), tone presentation rate (PR), and tone duration (TD) were systematically varied to examine whether neural responses correlate with effects of these variables on perceptual stream segregation. "A" tones were fixed at the best frequency of the recording site, while "B" tones were displaced in frequency from "A" tones by an amount = delta F. As PR increased, "B" tone responses decreased in amplitude to a greater extent than "A" tone responses, yielding neural response patterns dominated by "A" tone responses occurring at half the alternation rate. Increasing TD facilitated the differential attenuation of "B" tone responses. These findings parallel psychoacoustic data and suggest a physiological model of stream segregation whereby increasing delta F, PR, or TD enhances spatial differentiation of "A" tone and "B" tone responses along the tonotopic map in A1.     

Local symmetry breaking by impurities and mode splitting in doped SmS

We introduce the idea of local symmetry breaking by impurities to explain the recently observed splitting of the J=0-->1 propagating excitation in doped Sm1-xYxS. While preserving the global cubic symmetry of the crystal, Y impurities change the local crystal-field environment of each Sm ion from cubic to tetragonal, thereby splitting the J=1 triplet into a m(i).J=0 level with energy Delta(1) and a m(i).J=+/-1 doublet with energy Delta(2)>Delta(1). A model with a randomly oriented quantization axis m(i) fits not only the observed mode frequencies but also their intensities, which strongly depends on the wave vector.     

Diophantine properties of measures invariant with respect to the Gauss map

Motivated by the work of D. Y. Kleinbock, E. Lindenstrauss, G. A. Margulis, and B. Weiss [8, 9], we explore the Diophantine properties of probability measures invariant under the Gauss map. Specifically, we prove that every such measure which has finite Lyapunov exponent is extremal, i.e., gives zero measure to the set of very well approximable numbers. We show, on the other hand, that there exist examples where the Lyapunov exponent is infinite and the invariant measure is not extremal. Finally, we construct a family of Ahlfors regular measures and prove a Khinchine-type theorem for these measures. The series whose convergence or divergence is used to determine whether or not µ-almost every point is ψ-approximable is different from the series used for Lebesgue measure, so this theorem answers in the negative a question posed by Kleinbock, Lindenstrauss, and Weiss [8].     

Orientationally degenerate (OH)− centers in perovskite-type proton-conducting oxides: Low-temperature thermodynamics and H/D isotope effects

It is shown that proton-associated dipole centers (OH)⁻ can provide significant, glasslike contributions to the low-temperature properties of perovskite-type proton conducting oxides, such as ABO_3−y , doped with cations of lower valence. These contributions result from the splitting of the orientationally degenerate states of dipole centers by random crystal fields and proton tunneling. It is demonstrated that H/D (or H/T) substitution leads to large and abnormal isotope effects for the properties caused by (OH)⁻ degenerate states. The text was submitted by the authors in English.