Structure and conversions of the condensation products of phenols with unsaturated carbonyl compounds

The reaction of 3,4-xylenol with crotonaldehyde leads to the formation of 2, 6, 7-trimethyl-4-(4, 5-dimethyl-2-hydroxyphenyl)chroman, whose structure is verified by IR and UV spectra, by the synthesis of the methyl and the benzoyl esters, and by the investigation of the conditions and the products of pyrolisis.The IR spectrum of a paste of IV in vaseline oil was recorded on a IKS-14 apparatus     

A stochastic model and a variance-reduction Monte-Carlo method for the calculation of light transport

We compare the transport theoretic and a stochastic approach of modeling light propagation in the atmosphere. Computations of LIDAR return signals using algorithms based on the two different approaches show very good agreement of the numerical data. Furthermore, a deeper analysis of the formulas for the LIDAR return signal obtained from two kinds of modeling shows that they are equivalent. Combining these approaches and introducing splitting techniques, variance reduction Monte Carlo methods and codes are designed which are adapted to the configuration of the LIDAR. These codes allow the calculation of multiple scattering effects with high accuracy. Finally, we point out the importance and some perspectives of ultilization of multiple scattering in laser remote sensing of clouds.     

Local degeneration of waves in a thin waveguide

A thin, curved waveguide of variable width with an impedance condition on one of the walls is considered. Local degeneration of normal waves is studied. Coefficients for the transformation of waves as they pass through points of local degeneration are found.     

Compact invariant sets of the Bianchi VIII and Bianchi IX Hamiltonian systems

In this Letter we prove that all compact invariant sets of the Bianchi VIII Hamiltonian system are contained in the set described by several simple linear equalities and inequalities. Moreover, we describe invariant domains in which the phase flow of this system has no recurrence property and show that there are no periodic orbits and neither homoclinic, nor heteroclinic orbits contained in the zero level set of its Hamiltonian. Similar results are obtained for the Bianchi IX Hamiltonian system.     

Finding of <Emphasis Type="Italic">L</Emphasis><Subscript>2,3</Subscript> lines of the 148.16-keV γ transition in the <Superscript>161</Superscript>Ho nucleus

The preliminary experimental data on the spectrum of internal-conversion electrons of the erbium fraction in the range of electron energies near ～140 keV are reported. A photographic plate with a spectrogram of erbium fraction, exposed on the spectrometer of the Laboratory of Nuclear Problems (Joint Institute for Nuclear Research), was then measured on the PAVIKOM-1 microscopic complex (Lebedev Physical Institute). Due to the large number of spectral lines in this region, it was previously impossible to determine the intensities of the L ₂ and L ₃ lines of internal-conversion electrons for the 148.16-keV transition in the ¹⁶¹Ho nucleus. The use of the PAVIKOM-1 microscopic complex with a resolution of 0.01% made it possible to identify these lines and determine their intensities.     

Investigation of silicon structures with periodically varying porosity by x-ray diffractometry methods

The features of formation of silicon structures with a periodically varying porosity are investigated by X-ray diffractometry. It is revealed that the magnitude of anode current density corresponding to the formation of a layer with higher porosity that is part of a multilayer porous structure also affects the porosity of a second, less porous layer. As time elapses, the single-crystalline matrix of which porous layers consist is amorphized and a structure consisting of amorphous layers with a periodically varying density arises.