Synthesis and hydroxylation of 1-alkyl- and 7-alkyl- 1,3,7-triazapyrenium salts

The regioselectivity of quaternization of 1,3,5-triazapyrenes by alkyl halides has been studied. Oxidative hydroxylation of 1-alkyl- and 7-alkyl-1,3,7-triazapyrenium salts gives 1-alkyl-1,2-dihydro-1,3,7-triazapyren-2-ones or 7-alkyl-6,7-dihydro-1,3,7-triazapyren-6-ones respectively. In the absence of an oxidant the hydroxylation of the 1-alkyl-1,3,7-triazapyrenium salts leads to a hydrolytic cleavage of the heterocycle.     

Magnetic Properties of Monocrystal 57Fe/V Multilayers Investigated by CEMS,Nuclear Resonance Reflectivity in the Time Domain and Polarized Neutron Scattering

Hyperfine Interactions - We have performed a depth selective investigation of monocrystalline samples with composition [57Fe(10 ML)/V(5 ML)]20 and [57Fe(7 ML)/V(10 ML)]29 by means of synchrotron...     

Phase Transition in Y3Fe5O12 at High Pressures Observed by Raman Spectroscopy

JETP Letters - The vibrational properties of yttrium iron garnet Y3Fe5O12 at a high quasihydrostatic pressure are studied by the Raman spectroscopy method. Raman spectra are measured in a...     

Demonstrator of continuous-detonation air-breathing ramjet: Wind tunnel data

First experimental investigations were carried out into the detonation combustion of hydrogen in a demonstrator of an original-design air-breathing ramjet while blowing with an air flow at Mach 4 to 8 in an impulse wind tunnel, and for the first time under these conditions, continuous spin and longitudinal pulsed modes of detonation combustion of hydrogen in an annular combustor were detected.     

Interaction of elemental mercury with selenium surfaces: model experiments for investigations of superheavy elements copernicium and flerovium

The adsorption behavior of ¹⁹⁷Hg and ^183–185Hg on red amorphous selenium (red a-Se) and trigonal selenium (t-Se) was investigated experimentally by off-line and on-line gas chromatographic methods, in preparation of a sensitive chemical separation and characterization of the transactinides copernicium (Cn, Z = 112) and flerovium (Fl, Z = 114). Monte-Carlo simulations of a diffusion controlled deposition were in good agreement with the experimental results, assuming as interaction limits ?ΔH _ads ^red a-Se (Hg) > 85 kJ/mol, and ?ΔH _ads ^t-Se (Hg) < 60 kJ/mol. Both Se allotropes can be used as stationary surfaces in comparative gas-chromatographic chemical investigations of Cn and Fl.