Synthesis and the structure of tribromo(7-bromobicyclo[4.1.0]hept-7-yl)germane

A general procedure was developed for the synthesis of halocyclopropylgermanes. This procedure was used for the preparation of tribromo(7-bromobicyclo[4.1.0]hept-7-yl)germane. The molecular structure was established by GLC-mass spectrometry, ¹H NMR spectroscopy, and X-ray diffraction analysis.     

Blister Drop–Pellet Tests for Nitrates and Nitrites

A visual rapid test in the volume of a blister cell containing a mixture of dry reagents in the form of a pellet was proposed. This provides a rapid test effect immediately after opening the cell and adding several drops of a test liquid. Pellets were developed for the visual determination of nitrate ions in the concentration range 40–2000 mg/L; the pellets include azo and diazo components, organic acid, zinc powder, silica gel, and filler. The distribution of errors in visual determinations was studied for aqueous solutions and cucumber and tomato juices with the participation of unexperienced observers.     

Dipolar spirocyclic σ-complexes based on of 4,6-dinitrobenzofuroxan

The first dipolar spiro-σ-complexes with a superelectrophilic dinintrobenzofuroxan fragment and tropolone systems with diastereotopic substituents were synthesized. The kinetics of their enantiotopomerization, which occursvia cleavage-formation of the C_spiro-heteroatom bond, was studied by dynamic¹H NMR. The stereorigidity of dinitrobenzofuroxan spiro-complexes in this degenerated process increases in the series: tropolone<aminotropone<aminothiotropone≈aminotroponimine. The two last posses the highest kinetic stability compared to all known zwitterionic spiro-complexes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1509–1512, August, 1997.     

Study of Polarizer Characteristics with a High-Power Terahertz Free Electron Laser

Though wire grid and strip polarizers are widely used for control of submillimeter radiation, both calculated and experimentally measured values of their transmission are often contradict one another. We have measured the transmission of wire and thin-film photolithographic polarizers at a wavelength of 0.13-mm using 100 W free electron laser radiation and compared the results with previous experiments and calculations. Using a thin-film photolithographic polarizer we showed that radiation of the Novosibirsk FEL after traveling through a 14-m beamline is plane-polarized with the degree of polarization better than 99.6%.     

Visualization of radiation from a high-power terahertz free electron laser with a thermosensitive interferometer

A thermosensitive interferometer based on a plane-parallel glass plate is used for visualization of a high-power terahertz radiation. The plane wavefront of visible radiation emitted by a semiconductor laser is reflected from the two surfaces of the plate and forms on a screen an interference pattern recorded by a digital video camera. Terahertz radiation being measured is incident on the outer surface of the plate and heats a thin surface layer, which causes a shift of interference fringes. For K8 glass, a shift by one fringe corresponds to an absorbed energy of 5.1 J/cm². The problem of determining the sign of the phase shift was solved by comparing the interference patterns with the images obtained with an infrared imager sensitive to near IR radiation. The processing of interference patterns makes it possible to determine the power density distribution over the beam cross section of the Novosibirsk free electron laser. In these measurements, the absolute value of the beam power determined by integrating over the cross section was 65 ± 7 W for a 130-μm wavelength. Visualization of the complex image with a spatial resolution no worse than 1 mm and a frame repetition rate of 25 Hz is demonstrated.     

Modification of polycrystalline SnO2 and ZnO under the action of a high-power ion beam of nanosecond duration

The modification of polycrystalline oxides (SnO₂ and ZnO) under the action of a nanosecond high-power ion beam (HPIB) with current densities of 50–150 A/cm², which is accompanied by melting of initial particles of the surface layer, is investigated. It is established that submicron-sized particles of tetragonal SnO whose average size is 210 nm are formed on the SnO₂ surface irradiated by an ion beam with a current density of 150 A/cm². These particles have pronounced crystallographic faceting. When ZnO is irradiated by HPIBs with different current densities, a thin Zn film is formed in the sintered surface layer. Possible mechanisms of the observed conversions are discussed.     

Two-dimensional flows of a viscous binary fluid between moving solid boundaries

A class of exact solutions of hydrodynamic equations with additional Korteweg stresses is obtained which is characterized by a linear dependence of part of the velocity components on the space variable. In this class, exact solutions of two problems of binary fluid flow between moving flat solid boundaries was found. A family of particular exact solutions is obtained for the problem of viscous fluid flow between planes which approach or move away from each other according to a special law.     

Adducts of cobalt(ii) bis(salicylaldiminates) and redox-active phenoxazin-1-one: synthesis,structure, and magnetic properties

Adducts of cobalt(II) bis(salicylaldiminates) and 2,4,6,8-tetra-tert-butylphenoxazin-1-one were synthesized and their molecular and crystal structures were determined. According to the ESR and magnetochemical data, the metal atom is in the low-spin trivalent state (Co^III) due to the intramolecular electron transfer to the redox-active ligand. In the solid state, the mixedligand complexes are stable in air for several months, but in solution at elevated temperatures they dissociate to the starting components. Such a behavior detected by the temperature dependence of the effective magnetic moment is explained by the quantum chemical DFT calculations of the energy barriers of possible valence tautomeric dynamics, whose values were found to be higher than the enthalpy of dissociation.