On multiple orthogonal polynomials for three Meixner measures

Multiple orthogonal polynomials for three discrete Meixner measures with identical exponential decay at infinity are studied. These polynomials are the denominators of the type II Hermite–Padé approximants to some hypergeometric functions. The limit distribution of zeros of such polynomials scaled in a certain way is described in terms of equilibrium logarithmic potentials and in terms of algebraic curves.     

Effect of gas pressure on amplitude and duration of electron beam current in a gas-filled diode

The parameters of an electron beam generated in helium in the pressure range p = 10⁻⁴−12 atm are studied. Nanosecond high-voltage pulses are applied to a gap between a tubular cathode and planar anode, which is made of 45-μm-thick AlBe foil. Behind the anode, an electron beam is detected at a helium pressure of 12 atm. The pressure dependence of the beam current amplitude shows three peaks at p ≈ 0.01, ≈ 0.07, and ≈ 3 atm. The beam-induced glow of a luminescent film placed behind the foil and the discharge glow at different helium pressures in the gas-filled diode are photographed.     

New Investigations of the Crystal Structure of Lead Germanate Pb5Ge3O11

Crystallography Reports - Perfect stoichiometric Pb5Ge3O11 single crystals have been synthesized by the flux method. Their cationic and anionic stoichiometry is confirmed by chemical analysis. The...     

Phase Modulations in a Speech Signal

Acoustical Physics - Mathematical models of the phase function and its parameters in speech-signal analysis problems have been investigated. The phase spectrum of a speech signal has been...     

Synergistic effects of encapsulated phthalocyanine complexes in MIL-101 for the selective aerobic oxidation of tetralin

Metal phthalocyanine complexes encapsulated in MIL-101, and used as "ship-in-a-bottle" catalysts, show outstanding TONs in the aerobic oxidation of tetralin.     

Tunable continuous-wave operation of a Cr3+,Li+:Mg2SiO4 laser

Room-temperature tunable cw laser oscillation of Cr3+ ions in forsterite crystals (Mg2SiO4) codoped with chromium and lithium has been demonstrated, for the first time to the authors' knowledge, in pumping a crystal with a Ti:sapphire laser into the first excited level of Cr3+ ions (4A2-4T2 transition). The laser is smoothly tunable in the region of 1095-1170 nm. A slope efficiency as great as 4.4% has been achieved.     

Flow instability in the zone of laminar axisymmetric boundary layer separation

The stability of flow with laminar boundary layer separation from a body of revolution aligned with an incompressible gas stream is investigated in a wind tunnel. In several experimental regimes with respect to the Reynolds number hot-wire anemometry is used to determine the main parameters of disturbances which grow behind the separation line, thus initiating transition to the turbulent flow state. The relations between the frequencies, the spatial growth rates of the most “hazardous” disturbances, and the integral characteristics of velocity profiles obtained in the study are in good agreement with the analogous data for plane separation flows.     

Saturated nitrogen-containing heterocycles. 12. Stereochemical properties of hydroxyalkylpyrrolidines using 13C NMR spectroscopy

The ¹³C NMR spectra of fifteen compounds in a series of alkyl- and arylsubstituted cis-isomers of hydroxyalkylpyrrolidines have been recorded, and they have been fully interpreted on the basis of configurational and conformational assignments.For Communication 11, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1201–1204, September, 1988.     

Anisotropy of the ionic conductivity of CsCu2Cl3 single crystals

The conductivity of CsCu₂Cl₃ single crystals (orthorhombic system, sp. gr. Cmcm) has been investigated for different electric-field directions, perpendicular to the crystallographic c axis and along it, in the temperature range 390–530 K. The increase in conductivity with temperature is due to the ion-carrier transport with activation energies E _a = 0.65 and 0.80 eV for the directions perpendicular to and along the crystallographic axis, respectively. The anisotropy of the crystal ionic conductivity is found to be σ_⊥c /σ_∥c ≈ 40 at 435 K. The thermally activated contribution to the conductivity in the CsCu₂Cl₃ structure is determined by the transport of Cu⁺ ions.