Geometric theory of invariants of groups generated by reflections

A survey of results on a number of problems of the geometric theory of invariants of groups generated by orthogonal and skew reflections is given. The paper is a continuation of the author's surveys published in 1980 and 1984.Translated from Itogi Nauki i Tekhniki, Seriya Problemy Geometrii, Vol. 21, pp. 155–208, 1989.     

Quantum dynamics of single-photon detection

Dynamics of the elementary photoelectric conversion upon interaction of a single-photon mode with a bound electron in a one-dimensional rectangular potential well is considered. The spatial and temporal dynamics of the wave packet corresponding to a free photoelectron is investigated.     

Formation of peroxide compounds on the oxidation of lignin by oxygen in an organic solvent

The results are given of a determination of the steady-state concentrations of peroxide compounds on the oxidation of lignin by oxygen in dioxane. An iodometric method of determining peroxides was used, with spectrophotometric control of the amount of iodine formed. It was established that the achievable steady-state concentration of peroxide compounds on the oxidation of lignin is 0.28–0.44 wt. % of O_act (oxygen pressure 1 atm, temperature 50–80°C). With a rise in the temperature, the steady-state concentration of peroxide compounds decreased. The addition of water (30 vol. %) to the organic solvent led to an increase in the rate of accumulation of peroxide compounds. It has been shown that the presence of alkaline and acidic catalysts exerts no appreciable influence on the achievable steady-state concentration and the rate of accumulation of peroxide compounds during the oxidation of lignin.Bratsk Industrial Institute. All-Union Scientific Production Combine of the Pulp and Paper Industry, Leningrad. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 413–417, May–August, 1992.     

Influence of water on the mechanism of the electroreduction of 9-nitroanthracene in DMF

The comparison of the data on the preparative electroreduction of 9-nitroanthracene in the mixtures of DMF-H₂O was performed for the potentials of the first and second stages. It was shown that the protonation of the anion radicals of 9-nitroanthracene by water has virtually no influence on the course of their dimerization up to the content of the H₂O in the DMF equal to 50%. The sharp change in the ratio of the electrolysis products under the conditions of the two-electron ER of (I) when water is present in the solvent is explained by the high rate of protonation of the dianion of 9,9-dinitro-9,9, 10,10-tetrahydro-10,10-bianthryl by water and the subsequent reduction of this hydrodimer. The PMR spectra of the cis and trans isomers of 9,9-dihydroximino-9,9,10,10-tetrahydrobianthryl, which are formed by the reaction of the dimeric dianion with MeI and the subsequent thermal decomposition of the nitron ether, were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 873–877, April, 1991.     

Synthesis of ω- and (ω – 1)-acetylenic acids from five-, six-, or seven-membered cycloalkanones

A convenient method for the synthesis of - and ( – 1)-acetylenic acids involves free-radical oxidative scission of cycloalkanones containing five-, six, or seven-membered cycles to give the corresponding -olefinic acids followed by bromination of the latter and subsequent dehydrobromination under the action of alkalis.