Spatial amplification of a laser wave and the transverse spread of electrons in an undulator with a noncollinear configuration

The spatial amplification of a wave in a magnetostatic undulator with noncollinear electron and laser beams is studied in the framework of the dispersion relation for single-frequency and collective regimes. The dependence of the gain on the electron beam width is estimated with regard to the spatial boundedness of the beams. The laser power threshold at which the selection with respect to the transverse velocity is possible is obtained for a free-electron laser without inversion.     

Stereochemistry of 2-substituted 5,6-benzo-1,3,2-dioxarsepines

Russian Chemical Bulletin -     

PMR investigation of internal inhibited rotation in N1,N1-dimethyl-N2-trifluoro[chloro]acetylamidines of picolinic and nicotinic acids

Summary Hindered rotation around the bond in the N-acylamidines has been investigated by PMR spectroscopy, and the kinetic parameters of the hindered rotation have been determined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 758–762, April, 1981.     

Caste and Population Specificity of Termite Cuticule Hydrocarbons

The composition of hydrocarbons from the termites Reticulitermes lucifugus Rossi and Kalotermes flavicollis Fabr. belonging to different castes and populations was determined using GC and mass spectrometry. The role of cuticular hydrocarbons in olfactory recognition of termite caste and population status was demonstrated.__________Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–6, January–February, 2005.     

Stereochemistry of Seven-membered Heterocycles: XLIV. Spatial Structure of 4-R-3,5-Dioxabicyclo[5.1.0]octanes

4-R-3,5-Dioxabicyclo[5.1.0]octanes were prepared in good yields by reduction of the corresponding 8,8-dichloro derivatives in a system Li-t-BuOH. According to the data of dynamic ¹H and ¹³CNMR spectroscopy involving experiments in the NOESY mode the formal (R = H) at −93°C in (CD₃)₂CO exists in nearly equally occupied chair forms with endo- and exo-oriented three-membered ring. The like structure were found in the diastereomeric 4-Me(t-Bu)-analogs. The characteristic feature of ¹³C NMR spectra consists in considerable difference in the chemical shifts of the C⁸ atoms (Δδ∼16–17 ppm). The data on epimerization of diastereomers and calculations along AM1 procedure suggest for formal a three-component equilibrium including a twist-form.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 301–305.Original Russian Text Copyright © 2005 by Fedorenko, Baryshnikov, Khairutdinov, Vafina, Shtyrlin, Klochkov, Klimovitskii.     

Stereochemistry of seven-membered heterocycles 11. Isoenergy chair-twist conformation equilibrium in phthalylformal and its 2-phenyl derivative

Conclusions By means of dynamic¹³C NMR, spectra have been obtained for the frozen chair and twist conformers of phthalylformal and its 2-phenyl derivative. The -effects of the phenyl substituent have been analyzed for both conformational species. 2. The introduction of a phenyl group into position 2 of phthalylformal is not reflected in the magnitude of the conformational free energy.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1068–1071, May, 1983.     

Continuous organomagnesium synthesis of organometallic compounds

Continuous organomagnesium synthesis of a number of organic derivatives of 14th group elements of the periodic table was examined in a column apparatus with an agitator. An effect of a molar ratio of reactants, temperature in a reaction zone, and other factors was studied on the yield and composition of the products.