Optical diagnostics of dispersing He plasma

An experimental study has been made of the characteristics of radiation from a dispersing helium plasma. From measurements of the space-time dependence of the line intensities of the helium 2³P — n³D series we obtained the distribution of the populations of the n³D levels for n=3–10. The study has shown that over a wide range of conditions the high-lying levels (n=5–10) are in equilibrium with electrons while a substantial deviation from equilibrium is observed for levels n=3, 4. From the energy distribution of the populations of the upper levels we determined the space-time dependence of the electron temperature, which reflects the process of effective electron cooling during dispersal of the plasma. The gas temperature was estimated from the populations of helium singlet and triplet levels with n=5. The time distribution of the electron density in the plasma was found from the Stark broadening of the spectral lines.Deceased.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 15–19, November, 1992.     

Plasma radiation emitted by dense mixtures of rare gases excited by an electron beam and by a discharge

An experimental investigation was made of the radiation emitted from a plasma formed by rare gases (He, Ne, Ar, Kr, Xe) excited by a beam of electrons with different parameters and by discharge pulses (P= 0.1–0.5 atm, I=1 kA, U=10–15 kV, C=0.25 F). An investigation was made of the spectral composition and time characteristics of the radiation, and of their dependences on the excitation conditions. New molecular bands were observed in the near-ultraviolet and visible ranges. The uniquely large widths of these bands could be of interest in the amplification of light in a wide spectral range.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 56–73, January, 1992.     

Bromination of 6-Methyl-5-nitrouracil

Russian Journal of Organic Chemistry - At bromination of 6-methyl-5-nitrouracil with bromine in methanol a mixture formed of the initial compound with...     

Rheological properties of acrylonitrile—acrylamide—styrene copolymer solutions synthesized by classical and controlled radical polymerizations

Russian Chemical Bulletin - The results of a comparative study of the rheological properties of acrylonitrile copolymers solutions synthesized by classical and controlled radical polymerizations in...     

Acid-Base Properties of 6-Methyluracil-5-carbonitrile and Its N-Methyl Derivatives

Russian Journal of General Chemistry - The constants of acid-base equilibrium of 6-methyluracil-5-carbonitrile in water were determined spectrophotometrically. For the first time,...     

Halogenation and nitration of 1-carboxymethyl-5-methyluracil. Halophilic reaction involving acetic anhydride

Russian Chemical Bulletin - 1-Carboxymethyl-5-halo-6-hydroxy-5-methyl-5,6-dihydrouracils and 1-carboxymethyl-6-hydroxy-5-methyl-5-mtro-5,6-dihydrouracils were synthesized for the first time by...     

On the Stability of Invariant Sets of Discontinuous Dynamical Systems

We establish sufficient conditions for the stability, asymptotic stability, and instability of invariant sets of discontinuous dynamical systems.