Structural Phase Transformations in Al/Pt Bilayer Thin Films during the Solid-State Reaction

A sequence of phases forming during the solid-phase reaction in Al/Pt bilayer thin films has been investigated by in situ electron diffraction. It is shown that the amorphous PtAl₂ phase forms first during the solid-phase reaction initiated by heating. Upon further heating, PtAl₂, Pt₂Al₃, PtAl, and Pt₃Al crystalline phases sequentially form, which is qualitatively consistent with an effective formation heat model. The content of phases forming during the reaction has been quantitatively analyzed and the structural phase transformations have been examined.

     

Fatty-acid composition of certain species of marine mycelial fungi

The fatty-acid composition of seven strains of marine mycelial fungi was studied. GC and GC—MS showed that marine fungi of the genus Penicillium synthesized fatty-acid mixtures of saturated and unsaturated acids of similar compositions with different percent contents. Fatty-acid profiles of fungi associated with holothuria Chiridota ochotensis were characterized for the first time. Producers of branched 15:0 and dichloro- and cyclopropane-containing acids were observed. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 18–20, January-February, 2009.     

Solid-state synthesis and atomic ordering in thin Cu/Au films (atomic ratio, Cu : Au = 3 : 1)

In situ transmission electron microscopy investigations of the processes of solid-state synthesis and atomic ordering in bilayer Cu/Au nanofilms (atomic ratio, Cu: Au = 3: 1) are conducted. It is found that solid-state synthesis starts at 170°C. A Cu₃Au atomic-disordered structure (Fm3m space group; lattice constant, a = 3.76 ± 0.01 Å) forms at 280°C. Annealing the film for 1 hour at 380°C produced a Cu₃AuI (L1₂ type) atomic-ordered superstructure, a Pm-3m space group, and lattice constant, a = 3.76 ± 0.01 Å in the bulk of the film.     

Channeling of Auroral Kilometric Radiation During Geomagnetic Disturbances

JETP Letters - The electromagnetic fields measured on the ERG satellite are presented and their comparative analysis with measurements on the WIND satellite is carried out. The possibility of...     

Vibrational spectrum of Li2B4O7 crystals

Polarized IR reflection spectra of Li₂B₄O₇ crystals are studied in a spectral range of 80–1600 cm^?1 and compared with their Raman spectra. Based on the results of the dispersion analysis of the spectra, the frequencies, damping constants, and oscillator strengths of all vibrations are determined. The inversion of frequencies of the longitudinal and transverse vibrations of the A ₁ and E symmetry in a range of 900–1150 cm^?1 is found. Based on the data thus obtained, the effective charges are calculated and the types of chemical bonds are analyzed for structural groups of the Li₂B₄O₇ crystal.