Peculiarities of the interaction of dinitrobenzenes witht-BuNHMgBr andt-BuNHLi

Reactions ofm- andp-dinitrobenzenes witht-BuNHMgBr andt-BuNHLi were studied. The reactions afford azo- and azoxy-derivatives and products of nucleophilic substitution.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 739–741, April, 1993.     

Structures of two high-temperature Dy2TiO5 modifications

Single crystals of two structural modifications of high-temperature dysprosium titanate Dy₂TiO were grown. Using X-ray diffraction, the crystal structure of the cubic modification (space group Fd3m, a = 10.28(1)Å, Z = 10.4) was refined and the structure of a new monoclinic modification (space group B2/m, a = 10.33(1)Å, b = 3.653(5)Å, c = 7.306(6)Å, β = 90.00(7)°, Z = 2.4), which crystallizes in minor amounts together with the cubic phase, was determined. The lowering of symmetry from cubic to monoclinic is due to different distributions of the Dy³⁺ and Ti⁴⁺ cations over the sites present in the cubic cell.     

Crystal structure of sodium potassium zinc diphosphate NaKZnP2O7

Single crystals of NaKZnP₂O₇ were grown, and their crystal structure was determined by X-ray diffraction (space group P2₁/n, a = 12.585(5) Å, b = 7.277(5) Å, c = 7.428(5) Å, β = 90.00(5)°, Z = 4, 1916 F(hkl), R ₁ = 0.0461). The structure contains a 3D tetrahedral zinc phosphate framework with a system of intersecting channels running along the b and c axes. The sodium and potassium atoms are coordinated to six and seven oxygen atoms, respectively, and reside inside these channels; the potassium cations, which are larger than the sodium cations, are located at channel intersections.     

Ethylenediaminetetraacetato-monoperoxo complexes of vanadium(V)

Summary The monoperoxo complexes, M₂[VO(HEDTA)(O₂)]· 4H₂O, where M is K⁺ or NH ₄ ⁺ and H₄EDTA is ethylene-diaminetetraacetic acid, were prepared and characterized by Raman and i.r. spectra in the solid state and in aqueous solution. The single crystal X-ray study revealed a pentagonal bipyramidal anion structure with a tetradentate HEDTA(3—) ligand. The decomposition of complexes in aqueous solution to blue vanadium(IV) complexes as end products proceeds via a nonperoxo complex of vanadium.     

Study of the Anglular Structure of Emission from the Radio Galaxy 3C295 in the Decameter Wavelength Range

We present the results of observations of the angular structure of the radio source 3C295 at decameter waves using the URAN-1 and URAN-2 interferometers. It is shown that the radio image of 3C295 at these frequencies differs drastically from the structure of this object observed at higher frequencies. The simplest model of the structure of this radio galaxy, comprising one component with a Gaussian brightness distribution of angular size (7.4 ± 0.4)× (8.7± 0.4) at 25 MHz and (9.1± 0.5)× (10.6 ± 0.5) at 20 MHz, is determined. A decrease in the spectral density of the emission with decreasing frequency, observed below 50 MHz, is explained.     

Peskar' — An electron beam generator for industrial applications

The design of a electronic beam pulse generator for industrial applications is described. The parameters of the electron beam are 700 kV, 25 kA, and 1 μsec. The design features of the magnetic circuits and the test bench used to test and inspect them are described. Institute of High-Current Electronics, Siberian Division, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 98–102, December, 1995.     

Anomalous attenuation of longitudinal ultrasound in the intermediate state of pure type I superconductor

The dependence of ultrasonic attenuation on the direction of magnetic field H (H ⊥ k) in intermediate state of very pure gallium at T = 0.5°K was found to be anomalously different from the dependence observed at the same temperature and H = H_c in normal state. This phenomenon can be explained taking into account the anisotropy of the gallium Fermi surface.