Synthesis of acyclic quaternary ammonium compounds containing ω-alkoxyethyl and 2-hydroxyethyl substituents at the nitrogen atom

Russian Chemical Bulletin - A series of acyclic symmetric quaternary ammonium chlorides Me2(HOCH2CH2)N+(CH2CH2O)nR Cl– (n = 1, R = n-C9H19; n = 2, R = n-C6H13; n = 3, R = n-C3H7) was...     

Explicit integration of one problem of motion of the generalized Kowalevski top

In the problem of motion of the Kowalevski top in a double force field the four-dimensional invariant submanifold of the phase space was pointed out by [Kharlamov, M.P., 2002. Mekh. Tverd. Tela 32, 33–38]. We show that the equations of motion on this manifold can be separated by the appropriate change of variables, the new variables s₁, s₂ being elliptic functions of time. The natural phase variables (components of the angular velocity and the direction vectors of the forces with respect to the movable basis) are expressed via s₁, s₂ explicitly in elementary algebraic functions.     

Investigation of Ge and C layer deposition on a Si substrate using SIMS profiling

Structures grown using the technique of molecular-beam epitaxy during deposition of carbon and/or germanium atoms on an Si(111) surface were investigated experimentally and theoretically. Experimental profiles of in-depth component distribution were obtained using SIMS-profiling, whereas a complex technique of computer simulation taking into account diffusion and ballistic processes was applied for the calculated profiles.     

Tautomerism of Aza heterocycles: V. Structure of the spontaneous transformation products of 5-methyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo-[4,3-c]pyridin-3-one in crystal and solution

5-Methyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one exists as zwitterion with a proton localized on the nitrogen atom of the piperidine ring and negative charge delocalized over the pyrazololate fragment. The compound is stable in crystal but ustable in solution. Its chromatographic purification and attempts to recrystallize or synthesize by condensation of phenylhydrazine with alkyl 1-methyl-4-oxopiperidin-3-carboxylate on heating in alcohols or benzene lead to the formation of a complex mixture of products. Among these products, we isolated and identified 3a,3a′-methylenebis(5-methyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one), 1-methyl-3-(2-phenylhydrazinylidene)pyrrolidin-2-one, and 5-methyl-2-phenyl-3,5,6,7-tetrahydro-2H-pyrazolo[4,3-c]pyridine. The structure of methyl 3-(2-phenylhydrazinylidene)-4,5-dihydro-3H-pyrrole-2-carboxylate and 3a,5-dimethyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one was proved by NMR spectroscopy. 3a,5-Dimethyl-2-phenyl-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]pyridin-3-one was isolated as hydrochloride hydrate whose structure was determined by X-ray analysis.     

Separation of variables in the generalized 4th Appelrot class. II. Real solutions

We continue the analytical solution of the integrable system with two degrees of freedom arising as the generalization of the 4th Appelrot class of motions of the Kowalevski top for the case of two constant force fields [Kharlamov, RCD, vol. 10, no. 4]. The separated variables found in [Kharlamov, RCD, vol. 12, no. 3] are complex in the most part of the integral constants plane. Here we present the real separating variables and obtain the algebraic expressions for the initial Euler-Poisson variables. The finite algorithm of establishing the topology of regular integral manifolds is described. The article straightforwardly refers to some formulas from [Kharlamov, RCD, vol. 12, no. 3].     

Electromagnetic dissociation of relativistic 8B nuclei in nuclear track emulsion

Experimental data on fragmentation channels in peripheral interactions of ⁸B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process ⁸B → ⁷Be + p and to estimate its cross section. Events of ¹⁰C peripheral dissociation that were observed in the same exposure are described.     

Thermoelectric figure of merit of a material consisting of semiconductor or metal particles

It is found that the dimensionless thermoelectric figure of merit of a material consisting of a large number of ball-shaped semiconductor or metal particles can be much more than unity. The introduction of an insulator into the space between the particles is shown to sharply increase the power of the converter of heat energy into electric current energy.