Distribution of a nonstationary electron beam in a dense gas

The problem of the temporal and spatial dependences of the parameters of the action of a modulated fast-electron beam on a dense gas is posed on the basis of the transport equation. The problem is simplified by making it nondimensional and by transforming to the Fokker-Planck approximation. A Green's function formalism is developed for this problem and is used to express the solution of the general nonstationary problem in the form of a convolution of a nonstationary boundary flow with a stationary Green's function. The use of the derived equation is illustrated using as an example the solution of a problem with the simplest stationary Green's function corresponding to the straight-ahead approximation. This approximation is used to consider a general relativistic case with model scattering cross sections. The methods and results of a numerical computer solution of the nonstationary problem of electron retardation in the upper layer of the atmosphere are surveyed.Translated from Trudy Ordena Lenina Fizicheskogo Instituta im. P. N. Lebedeva AN SSSR, Vol. 145, pp. 172–188, 1984.     

2-Benzopyrylium salts. 27. Some transformations of 6-oxodibenzo[a,g]-quinolizinium salts

The synthesis of 6-oxodibenzo[a,g]quinolizinium perchlorate — an analog of the alkaloid berberine — and a number of its derivatives, including mesoionic compounds, was accomplished on the basis of a 1-unsubstituted 3-(2-methylenecarboxyaryl)-2-benzopyrylium salt. The interconversions of the compounds obtained in this research were studied.See [1] for communication 26.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1381–1387, October, 1982.     

Formylation and vinylformylation of 2,3-cycloalkenobenzopyrylium salts

Heating of 2,3-cycloalkenobenzopyrylium salts in acetic anhydride with excess formylating agent (dimethylformamide, formanilide, N-formylmorpholine, and N-phenyl-N-methyl-aminoacrolein) gives monoiminium salts, the hydrolysis of which yields aldehydes or, in the presence of hydrosulfide, thioaldehydes. On treatment with the Vilsmeier complex, 1-methylquinaldinium salts give diiminium salts, which are hydrolyzed to the corresponding aldehydes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 733–736, June, 1971.     

Photochromic and thermochromic spiropyrans

The preparation of 1,3-dithiolanium salts from 1,2-ethanedithiol and carboxylic acid chlorides, the subsequent condensation of which with aromatic o-hydroxy aldehydes leads to spiropyrans of the dithiolane series, is described. The PMR spectra were studied, and the photochromic properties are discussed.See [1] for Communication 9.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 47–50, January, 1980.     

Segregation of Components as a Result of High‐Power Laser Irradiation of Heterogeneous Condensed Media

The effects of periodic segregation of components in metastable (supercooled or supersaturated) binary alloys in the course of kinetic phase transformations as a result of laser irradiation of heterogeneous systems were studied analytically. Nonlinear processes of temporal and spatial selforganization of concentrationrelated structures were simulated using (i) a selfconsistent system of timedependent twodimensional equations for the distribution function for the sizes and spatial coordinates of the newphase particles and (ii) balance equations for the temperature and concentration of dissolved components; the latter equations account for nonlinearity of the particlesource function, sinks, for dependences of the phasetransition temperature on the surface curvature of particles and on the concentration of components, and for diffusive motion of particles in space. The domain of existence for the instabilities under consideration and the characteristics of the formed crystallizationrelated periodic structures are determined. It is established that nanoclusters formed during supersaturation of crystallizing material may play an important role in generation of selfoscillatory crystallization modes. Hydrodynamic aspects of liquidphase concentrationrelated stratification in heterogeneous systems based on immiscible components are considered.     

Ecological Aspects of the Nuclear Problem. Remote Monitoring

New ecological aspects of the nuclear problem are considered, such as an assessment of the consequences of a steady increase in radiation dosage and its influence on the state of ecosystems and the health of the populace, the possibilities of preventing and localizing radiation accidents by building underground nuclear power stations, and means for efficient remote monitoring of radiation sources. A physical interpretation of phenomena accompanying the release of radioactivity is given. The high efficiency of radar-based monitoring is shown. The potentialities of using laser probing are discussed.     

The distribution function of atomic level populations in a plasma

An analytic form is obtained for the population distribution function in an atomic plasma as a series in successive time derivatives of the population of the first level. The first approximation includes the well-known method of a stationary sink. The quasistationary distribution obtained for hydrogen agrees well with numerical calculations of recombination and ionization, and for lithium, helium, and argon the quasistationary distribution gives qualitative agreement with numerical calculations.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 18–26, July–August, 1972.We should like to thank B. F. Gordiets for a helpful discussion.