Reactions of azinium ions. 4. Reactions of quinoxalinium salts with nitroalkanes — Single-stage path to tetraazaheterocycles with bridged and framework structures

The addition of the carbanions of nitroalkanes of N-alkylquinoxalinium salts in an alcohol medium leads to dibenzo [d,k]-1,3,6,10-tetrasubstituted tricyclo[7.3.1.0^2,7]-and tetracyclo[7.3.1.0^2,70^6,13]tridecanes.For Communication 3, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–399, March, 1986.     

Electrodynamics of a convective cloud

An attempt has been made to describe analytically the electrodynamics of a convective cloud on the basis of a one-dimensional convective cell with solid gas rotation. The cloud electrification is due to the interaction between heavy (large raindrops and particles of hail) and light (microparticles of water and ice) particles. As a result, the particles acquire unlike electric charges. The large-scale electric field in the cloud is stipulated by boundary effects and influences considerably the motion of the heavy fraction of aerosol particles. A scenario is proposed for the development of an intracloud charge, by which the large-scale electric field does not reach the breakdown value, staying at the level of the corona discharge field, while an increase in the irregular component of the electric field is continued and achieves the breakdown value in the small-scale electric cells induced by analogues of plasma beam instabilities. The basic electric discharge occurs against the background of multiple discharges inside the cell which provide for the leader lightning channel. Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, Nos. 1–2, pp. 123–137, January–February, 1997.     

Interaction of Large‐Scale and Small‐Scale Oscillations During Separation of a Laminar Boundary Layer

The mutual influence of shortwave oscillations (instability waves of the separated boundary layer) and longwave disturbances at the frequency of shedding of periodic largescale vortices is experimentally studied in flow separation behind a step. The possibility of controlling the process of vortex formation by exciting amplifying disturbances in the shear layer is demonstrated.     

Determination of Concentration of Rare Earth Ions Yb3+, Er3+, Tb3+, Ho3+, Tm3+ in Monocrystals of Yttriumaluminum Garnets on Basis of Magnetic Susceptibility

Crystals of solid solutions (R_xY_1-x)₃Al₅O₁₂ (where R is rare earth ion Er³⁺, Yb³⁺, Tb³⁺, Ho³⁺, Tm³⁺) with garnet structure were grown. The temperature dependencies of magnetic susceptibility for these crystals were obtained. On the basis of measurement of magnetic susceptibility a non-destructive technique for determining the concentration of rare earth ions in yttrium-aluminum garnets was developed.