Current Distribution in a Gyrotropic Microstrip Structure when Excited by a Plane Electromagnetic Wave

The problem of the distribution of the surface current density in a gyrotropic microstrip structure representing an infinitely thin ideally conducting strip arranged on a substrate of a chiral metamaterial metallized from one side and excited by a plane wave is reduced to a one-dimensional singular integral equation with a Cauchy singularity. The complex current distributions along the strip conductor are presented for different types of substrate and the wave-incidence angles.     

Electrochemical noise spectroscopy: Method of secondary Chebyshev spectrum

A new method of electrochemical noise diagnostics is presented: the method of the secondary Chebyshev spectrum based on the splitting of an individual spectral line in the primary Chebyshev spectrum with formation of a system of spectral lines of the secondary Chebyshev spectrum. Algorithm for calculation of the secondary Chebyshev spectrum is developed. The suggested method based on analysis of noises measured in a specific electrochemical system is tested. It is shown that the new method allows determining the differences in the state of the electrochemical system more reliably, than the method of primary Chebyshev noise spectra.     

Impedance and Photoadmittance of Passive Iron Electrodes in Different Solutions

Electric characteristics of the oxide film at the surface of an anodized iron electrode in 0.5 M Na₂SO₄, NaNO₃, and Na₂MoO₄ solutions are studied using the impedance and photoadmittance measurements and taking polarization curves. The impedance frequency spectra correspond to an equivalent circuit comprising two parallel (RC) chains connected in a series. The relaxation time of the high-frequency circuit approaches that of the photopotential; hence, it can be related to the impedance of the oxide film. The low-frequency component of the impedance describes the impedance of the film/solution interface. In the Na₂SO₄ solution, the oxide film resistance is significantly higher and the capacitance is lower than in two other solutions, which can be explained by the film thickening. The marked concurrent decrease in the resistance and increase in the capacitance of the film/solution interface at 1.2 V in all solutions is caused by oxygen adsorption, which precedes oxygen evolution.     

Iron complex redox system as a mediator for a dye-sensitized solar cell

Photoelectric parameters of a dye-sensitized solar cell (DSSC) based on nanocrystalline titania with an adsorbed commercial sensitizer Ruthenizer 505 and a redox system based on the [FeL₂] · 2Otf complex (where L = 4′-(4-bipyridyl)-2,2′:6′,2″-tert-pyridine and Otf^? =CF₃SO ₃ ^? ) as the mediator are studied. When illuminated with a power of 100 mW/cm2, the DSSC voltage with the mediator under study and the iodide/triiodide redox pair have close values of 470 and 480 mV, respectively. The current-voltage characteristics of the DSSC with the iron complex mediator are far lower than for the iodide/triiodide redox pair. Our data indicate the slower reduction kinetics of the oxidized sensitizer species for the iron complex. The reason for this may be associated with the shift of the redox potential toward positive values in going from the iodide/triiodide redox pair to the iron complex, and thereby a reduced driving force for the reduction of the oxidized sensitizer species. We also cannot rule out that the DSSC characteristics are affected by the reduction on the photoanode of the oxidized mediator species as a result of the high reversibility of the iron complex mediator redox system.     

Novel 2′-(pyridin-4-yl)-5′-(pyridin-2-yl)-1′-(pyridin-2-yl)methylpyrrolidinyl[60]fullerene-hydroxyoxo(5,10,15,20-tetraphenyl-21H,23H-porphynato) molybdenum(V) dyads

Interaction between hydroxyoxo(5,10,15,20-tetraphenylporphyrinato)molybdenum(V) and 2′-(pyridin-4-yl)-5′-(pyridin-2-yl)-1′-(pyridin-2-yl)methylpyrrolidinyl[60]fullerene in toluene has been studied by means of spectrophotometry. The reaction proceeds via two stages: rapidly established equilibrium between the reactants and their molecular complex 1: 1 [K = (1.97 ± 0.52) × 10⁴ L/mol] followed by slow irreversible displacement of hydroxy group into the second coordination sphere to form cationic outer sphere complex (k = 0.26 L s^?1 mol^?1). The effect of fullerene fragment on pyridine fragments coordination has been considered.     

Accelerator mass spectrometer for the Siberian Branch of the Russian Academy of Sciences

A concept of an accelerator mass spectrometer intended for the Siberian Branch of the Russian Academy of Sciences is suggested. Preliminary tests have been conducted, and a carbon isotope having a mass of 14 amu has been detected in a charcoal sample.     

Quantum-chemical interpretation of the mass spectra of pyrrole,furan, and thiophene

A simple quantum-chemical interpretation of the mass-spectrometric fragmentation of organic molecules in which the probability of the cleavage of the bonds under the influence of electron impact is related to their self-consistent -electron orders and the possible rearrangement processes are described on the basis of the long-range bond orders is proposed. This approach was tested in the case of pyrrole, furan, and thiophene.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 620–624, May, 1987.     

Structure of isohyperectine — An alkaloid fromHypecoum erectum

A base with the composition C₂₄H₂₁O₆N₃ isomeric with hyperectine which has been called isohyperectine, has been isolated from the epigeal part ofHypercoum erectum L., and its structure has been established by chemical and spectral methods.     

Perimidine in the hetarylation reaction

Indoles and pyrroles were hetarylated by perimidines in the presence of benzoyl chloride. N-Acyl derivatives of 2-indolyl(pyrrolyl)-2, 3-dihydroperimidine were synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1682–1685, December, 1976.