Three-dimensional modeling of amplitude-object imaging in scanning near-field optical microscopy

The imaging properties of the transmission-illumination mode of a scanning near-field optical microscope are investigated. Three-dimensional calculations of the power transmitted into classically allowed and forbidden regions for a nonsymmetrically positioned amplitude object are implemented by use of the finite-difference time-domain solution of Maxwell's equations. The evolution of the images with the distance from the object as well as the effect of the polarization of the illumination is shown. The computations show that for applications involving the imaging of an amplitude object, the use of the allowed light is preferred. Collection of light from both the allowed and the forbidden zones leads to degraded contrast and resolution.     

Ti/TiO2 indicator electrodes formed by plasma electrolytic oxidation for potentiometric analysis

Ti/TiO₂ indicator electrodes were prepared by plasma electrolytic oxidation (PEO) method in the tetraborate electrolyte and were used for potentiometric indication of chemical reactions of different types and for analysis of surface and industrial wastewaters on the example of potentiometric determination of alkalinity and chloride. The electrodes formed at current densities of 0.05, 0.1, 0.15 and 0.2 A/cm² are different in composition, surface morphology and electroanalytical properties. The electrodes formed at a current density of 0.05 A/cm² exhibit the highest pH-sensitivity and generate the highest analytical signal at the equivalence point in the acid–base and precipitation titrations. The maximum analytical signal at the equivalence point, exceeding in magnitude the analytical signal, obtained by classical Pt electrode in oxidation–reduction and complexometric titrations generates PEO layers formed at a current density of 0.05 A/cm² and a platinum-modified nanoparticles. The results of the potentiometric titration of the surface and technogenic waters using as indicator Ti/TiO₂ electrodes are comparable with the conventionally used glass electrode (to determine alkalinity) and Ag electrode (to the determine chloride) and the results of visual titration. The advantage of the obtained metal oxide systems is the ability to determine two hydrochemical parameters due to their multifunctionality and opportunity to work with a single electrode. In addition, these sensors offer some analytical characteristics such as sensitivity, good reproducibility, high mechanical stability and a simple preparation procedure.     

Salts of 2- or 3-haloalkylamines in the synthesis of <Emphasis Type="Italic">N</Emphasis>-aminoalkyl derivatives of heterocyclic and aromatic amines

Reactions of 2-haloethyl- or 3-halopropylamine salts with NH-substrates (indoline, 1,2,3,4-tetrahydroquinoline, aniline, and N-ethylaniline) in the presence of NaHCO₃ in water furnished various N-aminoalkyl derivatives of heterocyclic and aromatic amines.     

Effect of the Composition of Oxide Layers Formed by Plasma Electrolytic Oxidation on the Mechanism of Peroxide Oxidative Desulfurization

The peroxide oxidation of thiophene, thioanisole, and dibenzothiophene in the presence of Ce, Zr, Ce + Zr, W, and W + Zn oxide layers formed by plasma electrolytic oxidation on the titanium surface was studied. The composition of the resulting composites was found to affect the activity and conversion of the organosulfur substrates. It was shown by the radical inhibition method that the composites differed in the mechanism of their catalytic action.     

Effect of Heating Procedure and Annealing Temperature on Transmission Spectra of sp1-Carbon Films Synthesized by the Ion-Plasma Method

Journal of Applied Spectroscopy - The influence of the heating procedure and annealing temperature in air on the transmission spectra and morphology of linear-chain carbon films synthesized by the...     

Deposition of cobalt-containing films on titanium by plasma electrolytic oxidation

The possibility of forming Co-containing coatings on titanium by plasma electrolytic oxidation and by a combination of oxidation and impregnation methods using an aqueous solution of sodium silicate as the base electrolyte was examined. Comparative analysis of the composition and structure of the systems obtained and of their activity in oxidation of CO to CO₂ was performed.     

Crystal structure of cocrystals 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.05.9.03.11]dodecane with 7H-tris-1,2,5-oxadiazolo (3,4-b:3′,4′-d:3″,4″-f) azepine

The crystal structure of the bimolecular crystal of CL-20 with new promising highly energetic compound 7H-tris-1,2,5-oxadiazolo[3,4-b:3′,4′-d:3″,4″-f] azepine is obtained and studied.     

Growth and Study of Properties of Mixed Crystals (NH4)2NixCo1 –x(SO4)2 · 6H2O

Crystallography Reports - Mixed crystals (NH4)2NixCo1 –x(SO4)2 · 6H2O have been grown from aqueous solutions of different compositions by reducing the solution temperature in two growth...     

Growth and properties of mixed K2Ni x Co1−x (SO4)2 · 6H2O crystals

Optically homogeneous mixed K₂Ni _x Co_{(1 ? x)}(SO₄)₂ · 6H₂O crystals are grown from solutions of different compositions by the temperature-reduction technique in static and dynamic regimes. The optical characteristics of the grown crystals are measured: transmittance reaches 80% in the wavelength range of 240–290 nm and no more than 9% in the visible spectral range. The thermal stability of the crystals is studied. It is established that the thermal stability of mixed K₂Ni _x Co_{1 ? x} (SO₄)₂ · 6H₂O crystals is higher than that of K₂Co(SO₄)₂ · 6H₂O crystal. The defects of the mixed crystals grown in static and dynamic regimes are investigated by X-ray topography.     

Determination of Melting Points for A2B6 Compounds

A new technique of rapid heating, recording both the melting and evaporation processes in an open system was proposed to determine the melting points of A2B6 (A=Zn, Cd) compounds. The different melting character and temperatures were detected for the equiatomic and non-stoichiometric composition of A2B6. A fit of these data to previously obtained results was considered and the reasons for their discrepancy were discussed. This revised version was published online in July 2006 with corrections to the Cover Date.