Cation-exchange fabric prepared by electron beam-induced graft copolymerization of binary monomer mixture

Applying the electron-beam preirradiation method in air the cation - exchange fabric (CEF) containing sulfonic acid (R-SO₃H) groups was prepared by graft copolymerization of sodium styrenesulfonate with acrylic acid onto non woven polypropylene fabric. The effect of reaction conditions on the grafting yield and reaction mechanism was examined. The ion-exchange properties towards Cu(II) and Co(II) ions of the CEF were investigated depending on the form of the CEF and a pH of the solution. It was found that the synthesized CEF contains both strong acid groups (R-SO₃H) and weak acid (R-COOH) groups in almost equal proportion. The utilization of the CEF in Na₊ form allows to make the best use of its ion-exchange capacity.     

Study of optical and magneto-optical properties of CoFe–HfO2 granular magnetic films

Granular films of composition (CoFe)_x(HfO₂)_1−x with continuous variation of the Co_0.5Fe_0.5 volume fraction in the range 0.1<x<0.9 have been prepared by e-beam co-evaporation. The optical properties of the thin granular composite films have been determined from transmission and reflection spectra in the 300–1100 nm region. The optical characteristics of the granular films as a function of x were also determined by the ellipsometrical method at λ=632.8 nm. We find that the transmission and reflection spectra and the dielectrical function have anomalies near the percolation threshold at x_p≈0.45. The Faraday rotation in the films was determined at λ=632.8 nm. The spectral dispersion of Faraday effects have peak in the region of the plasmon frequency. The Faraday effect is greatly enhanced near x_p. The calculated optical and magneto-optical parameters, described in the framework of the effective medium approximation, are in qualitative agreement with experimental data.     

Optical properties of iron alloys with heavy rare-earth elements

Spectral-ellipsometric measurements by the Beatty method were made in the region from 1 eV to 4 eV at temperatures of 100, 293, and 700 K to determine the relation between the distinctive features of the optical absorption spectrum and the principal parameters of the electron energy spectrum in iron alloys with rare-earth elements. The fundamental bands of interband optical absorption of Fe₂-R alloys (R=Gd, Ho, Er) in the region 2.8–3.1 eV are formed by indirect transitions from d-like states, which are genetically bound to 3d–5d electrons of the transition metal and the rare-earth metal, in a state above the Fermi level.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 64–67, December, 1988.We thank our senior research colleague V. A. Domyshev for supplying the samples and carrying out the x-ray structure analysis.     

Studies of molybdenum in Mo?Ti oxide catalysts

ESR studies indicate that in Mo–Ti oxide catalysts prepared via the addition of ammonium paramolybdate to pasted titanium hydroxide, Mo⁵⁺ ions are observed in three states: in heteropoly blue, disperse MoO₃ and a solid substitutional solution in TiO₂.

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, , - , - Mo⁵⁺— , MoO₃ TiO₂.

     

Steroids of the spirostan and furostan series from plants of the genus Allium. XXI. Structure of alliospiroside a and alliofuroside a from Allium cepa

Two new steroid glycosides have been isolated from the generative organs (pericarps and peduncles) ofAllium cepa L.: alliospiroside A and alliofuroside A. According to chemical transformations and spectral characteristics, alliospiroside A has the structure of (25S)-spirost-5-ene-1,3-diol 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside]. The structure of (25S)-furost-5-ene-1,3,22,26-tetraol 20-O--D-glucopyranoside 1-O-[O--L-rhamnopyranosyl-(1 2)--L-arabinopyranoside] has been established for alliofuroside A.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 188–196, March–April, 1986.     

Magnetooptical properties of Co-SiO<Subscript>2</Subscript> granular films

The structural, optical, and magnetooptical properties of Co-SiO₂ granular films are studied. It is found that the magnetooptical response is considerably enhanced in samples with a metal component concentration close to the percolation threshold. The Co nanogranules formed in the SiO₂ matrix exhibit ferromagnetic properties and are ordered into the fcc structure, which is confirmed by magnetooptical investigations. The magnetooptical properties of nanocomposites are simulated in the effective-medium approximation. It is shown that the singularities found in the magnetooptical spectra are related to the excitation of plasmon resonances in granular films.