New autooscillation chemiluminescence reaction of 4-oxyquinoline oxidation by bromate ions

A new autooscillation chemiluminescence reaction of 4-oxyquinoline oxidation by bromate ions, catalyzed by cerium ions and tris-(2,2-dipyridine) ruthenium complexes, has been discovered.

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Observation of a new surface state on4He crystal interfaces

The equilibrium shape ofhcp ⁴He crystals has been studied at temperatures 0.05≤T≤0.7 K by means of a high precision optical interferometer. We find that the profile of the interfacial boundary, close to an almost horizontal c-facet, has a well-defined slope discontinuity separating two angular regions with different behavior of the surface stiffness. For surfaces tilted by an angle ϕ≤100 μrad with respect to the c-facet, we obtain, contrary to the linear angular dependence predicted by current theories.     

On permittivity measurement by a resonance method

In a quasioptical approximation we develop a theory of an open cavity with a dielectric plate placed normally to the cavity axis. We find conditions under which some natural frequencies of the cavity are practically independent of the plate position in the cavity. From experimental measurements of one of these frequencies and with variation of the length of the cavity with and without the plate, with the same oscillation- mode structure, we determine the refractive index and plate thickness. Coincidence between the obtained (design) thickness and mechanically measured one is a correctness criterion for the results obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 5, pp. 615–623, May, 1996.     

Effect of surface excitations on the reflection electron energy loss spectrum in silicon

The results of investigating the relative contribution of surface excitations to the reflection electron energy loss spectrum in pure silicon are presented. The primary electron energy is in the range 60–1000eV. Good agreement is obtained between the experimental values of the surface parameter P _S and theoretical calculations. The relative contribution of surface excitations is also determined by decomposing the integral reflection electron energy loss spectra into Gaussian curves.     

Vibrations of copper atoms in Pr2CuO4

The method of isotopic contrast in combination with inelastic neutron scattering has been used to investigate the vibrational spectrum of the copper atoms in Pr₂CuO₄. It is shown that the energy positions of the features of the vibrational spectrum of copper in Pr₂CuO₄ and CuO (which also has a planar oxygen coordination of copper) coincide. We conclude that the dynamical behavior of the copper atoms is formed mainly by their interaction with the nearest-neighbor oxygen atoms. Fiz. Tverd. Tela (St. Petersburg) 41, 1149–1153 (July 1999)     

Total Transformation of an Electromagnetic Wave Incident on a Corrugated Boundary between Transparent Dielectrics to a Transmitting Wave of the (-1)st-Order Harmonic

We present the results of a theoretical and experimental study of a new phenomenon of total transformation of an electromagnetic wave incident from a dielectric on a corrugated boundary between two transparent dielectrics to a transmitting wave of the (-1)st-order harmonic propagating in the other dielectric. The theoretical study is based on numerical solution of the full-wave equations for electromagnetic field. The experimental study is made using a Teflon prism with a corrugated surface located in a two-mirror resonator.     

Boson Peak in Amorphous Graphene in the Stable Random Matrix Model

Physics of the Solid State - The effect of disorder in the distribution of force constants on optical and acoustic phonons in the scalar model of crystalline graphene is studied for both...     

Wideband Windows for Millimeter- and Submillimeter-Wave Vacuum Devices

Radiophysics and Quantum Electronics - We present the results of a theoretical calculation and an experimental study of double-sided antireflective processing of a dielectric plate by creating a...     

Atomic dynamics of the α-(Al,Si)CuFe alloy: A crystalline approximant of a quasicrystal...

The atomic dynamics of the Al_0.550Si_0.070Cu_0.255Fe_0.125 alloy with the structure that approximates the structure of an icosahedral quasicrystal with a similar chemical composition has been investigated using inelastic neutron scattering. The partial vibrational spectra of copper, iron, and aluminum atoms and the total spectrum of thermal vibrations of the compound have been directly reconstructed from the experimental data for the first time. A combined analysis of the results obtained and the data on the atomic dynamics of the i-AlCuFe icosahedral quasicrystal has been performed.     

Low-energy lattice excitations in the decagonal Al-Ni-Fe and icosahedral Al-Cu-Fe quasicrystals and the (Al,Si)-Cu-Fe cubic phase

The specific heat of decagonal Al_71.3Ni_24.0Fe_4.7 and icosahedral Al₆₂Cu_25.5Fe_12.5 quasicrystals and the Al_55.0Si_7.0Cu_25.5Fe_12.5 cubic phase approximating the structure of the icosahedral alloy has been studied in the temperature range 4.2–40.0 K. All the three compounds exhibit low coefficients of the electronic heat capacity and pronounced deviations of the low-temperature lattice heat capacity from a cubic temperature law in the range 5–10 K. The results obtained by the thermodynamic method and inelastic neutron scattering have been compared and analyzed. It has been established that, at energies ɛ < 14 meV, the spectral density of thermal vibrations in the icosahedral quasicrystal is substantially higher than those in the cubic approximant and in decagonal quasicrystal.