Harrington’s desirability function for natural water quality assessment

The theoretical analysis of the possible application of Harrington’s desirability function for the state of natural ecosystems assessment was made. It was shown that the desirability function with double limiting should be used for water quality objects assessment. The function makes it possible to eliminate arbitrary rule while the number of quality classes at different ways of optimization (typification, classification etc.) of information was determined. This resulted in mathematically valid limitation to the maximum 5 types of the first level. It was underlined that if even one particular response or a particular desirability function does not satisfy the requirements, the general estimation should be considered unsatisfactory, in spite of the fact that the other parameters (properties) of the studied system were satisfied. The tables were made which gave the possibility to assess the up-to-date state of the Rybinsk Reservoir ecosystem according to the content of nutrients and organic matters on the basis of future mesurments. The seasonal pattern of hydrophysical, hydrochemical and hydrobiological processes should be taken into account in order to make more accurate the water quality assessment at the concrete time in the definite site in the Rybinsk Reservoir area.     

Five-membered 2,3-dioxo heterocycles: XCVIII. [4 + 2]-cycloaddition of alkyl vinyl ethers to 3-aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones. A new synthetic approach to heteroanalogs of 13(14→8)-abeo steroids

3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with alkyl vinyl ethers according to the [4 + 2]-cycloaddition pattern with formation of substituted (1S*,16R*)- and (1R*,16R*)-16-alkoxy-14-aryl-3,15-dioxa-10-azatetracyclo[8.7.0.0^1,13.0^4,9]heptadeca-4,6,8,13-tetraene-2,11,12-triones. The structure of (1S*,16R*)-7-chloro-16-ethoxy-14-phenyl-3,15-dioxa-10-azatetracyclo[8.7.0.0^1,13.0^4,9]heptadeca-4,6,8,13-tetraene-2,11,12-trione was determined by X-ray analysis. A new synthetic approach was developed to heteroanalogs of 13(14→8)-abeo steroids, substituted 3,15-dioxa-10-azatetracyclo[8.7.0.0^1,13.0^4,9]heptadecanes.     

Chemoselectivity control in the reaction of a dinuclear chloro-bridged cyclopalladated complex with potassium diphenylphosphide

Reactions of KPPh₂ with the dimeric cyclopalladated complex {Pd(N∩C)(μ-Cl)}₂1 derived from N,N-dimethylbenzylamine were studied using different reagent ratios, temperature, reaction time, concentrations and solvents. Complex 3, the μ-Cl-μ-PPh₂ analog of 1, was obtained in 76% yield in the one-hour reaction using the 1:1 ratio of dimer 1 and KPPh₂ in THF at rt. ortho-(Diphenylphosphino)benzylamine 4 was synthesized in 58% yield by reacting complex 1 with 4.5 equiv. of KPPh₂ in THF at rt. A possible mechanism of the aminophosphine formation is proposed on the basis of the experimental data including ³¹P{¹H} NMR spectra of reaction mixtures.     

Magnetic anisotropy of Tb-Co amorphous films

A systematic investigation of the magnetic properties of Tb-Co amorphous films prepared using radio-frequency ion sputtering in a uniform magnetic field has been carried out. The main regularities of the change in the magnetic anisotropy parameters as a function of the composition (8–43 at % Tb), measurement temperature (5–350 K), and annealing temperature (up to 200°C) have been established. It has been shown that their interpretation can be performed within the framework of the model that takes into account the fluctuating local magnetic anisotropy of the terbium ions, columnar microstructure, and anisotropy of elastic stresses.     

Erosion of solid surface under irradiation by high-power submicrosecond ion beams

The erosion of a solid surface under high-power pulsed ion beams is considered. The values of atom yield from an irradiated surface due to the evaporation are obtained by numerical simulation. The effect of beam parameters and target characteristics on atom emission intensity was investigated. The technological capabilities of high-power submicrosecond ion beams for solid surface etching are assessed.     

Luminescence of Single Semiconductor Nanocrystals at Room Temperature as Observed with Confocal Microscopy

Optics and Spectroscopy - Luminescent images of a few distinguishable alloyed semiconductor quantum dots obtained at room temperature using confocal scanning microscopy with spectral and temporal...