MATHEMATICS >
In the article, we consider the equation y′′=(λ-(1/k) y′2)(k/y+ 2y/(1-x2-y2)) in the semicircle 1-x2-y2>0, y=y(x)>0, kλ>0 , to which the generalized Toda lattices with a Hamiltonian containing two exponents reduce.
For sufficiently small in absolute value λ, this equation can be replaced by a simpler equation setting λ = 0. It is proved that the latter has one-dimensional symmetry group and reduces to a differential first-order equation, by means of which one can get an arbitrarily accurate description of the general solution of the simplified second-order equation near the boundary of the semicircle.
PHYSICS >
CHEMISTRY >
Film polarizers based on polyvinyl alcohol (PVA), a new dichroic dye – sodium 2-hydroxy-5-((2-methoxy-4-((4-sulfonatophenyl)diazenyl)phenyl)diazenyl) benzoate (M12), and mixtures of dichroic dyes polarizing in a wide spectral range (330–685 nm) are developed.
The work is devoted to the study of the influence of anion cadmium salts (chloride, nitrate and acetate) on the ligand function of the ion (CdBr42−)-selective electrode (ISE). The graphical form of the ligand functions of film electrodes in a wide concentration range of Cd2+-ions (from 1 ∙ 10–4 to 0.1 M) is described and the influence of anion cadmium salts on the function of the ISE is explained in details. It is established that the increase in the concentration of Cd2+-ions has a double impact on the response characteristics of the CdBr42−-selective electrode. Also, it is established that the most suitable response characteristics are peculiar to the ligand functions of the CdBr42−-selective electrode based on cadmium acetate. The mathematical model of the ligand functions of the ISE based on trianoniloctadecylammonium is calculated using the system of computer algebra Mathematica 6.0.
Activated ester of a carboxylic derivative of europium diethylenetriaminetetraacetate has been synthesized by the interaction of europium salt of diethylenetriaminepentaacetic acid aminoethylamide with di-N-succinimidyl-p-phthalate. This reagent was applied to introduce rare earth metal ions in animal immunoglobulins (monoclonal antibodies). The proteins labelled with Eu3+ provide the required characteristics of fluorescence intensity, background, sensitivity and selectivity in diagnostic systems of lanthanide immunofluorometric assay.
Introduction of molybdenum trioxide to gas sensing materials based on titanium dioxide results in a considerable increase of the output signal in the hydrogen-air environment. It is established that the value of the output signal reaches the maximum at the 1 mol. % MoO3 content in the composite material. Improved gas sensing characteristics of TiO2:MoO3 composite correlate with the structural and phase peculiarities of this system – the inhibition of TiO2 crystallization in the TiO2:MoO3 system, the shift of anatase-rutile phase transition to the higher temperature area in comparison with the temperature of this transition in unloaded TiO2, and with the presence of different types of tetrahonal distortions in MoO6 octahedrons, which ensures the MoO3 lattice high activity in the processes of hydrogen catalytic oxidation, and also with the crystallization of highly dispersed molybdenum oxide with a particle size of 10 nm.
Luminescent properties of Pr0.1La0.9InO3 and Pr0.0995La0.9005Cr0.005In0.995O3 solid solutions were investigated. It was shown that Pr0.1La0.9InO3 and Pr0.0995La0.9005Cr0.005In0.995O3 have a promising application as phosphors for white LEDs. It was found that Cr3+ ion is a good sensitizer of the Pr3+ ion photoluminescence in LaInO3-based phosphors.
BIOLOGY >
The influence of the pileup and mixing of water on the concentration of dissolved nitrate nitrogen, ammonium nitrogen, and phosphorus in the littoral zone of eutrophic Lake Obsterno (Belarus) has been studied.
This concentration was determined for the two types of the littoral zone – with and without water-air vegetation (Scirpus lacustris). After the pileup the concentrations of PO4–, NO3–, NH4+ ions increased. The increasing of PO4– was higher in the littoral zone without vegetation, but NH4+ – in the littoral with vegetation.
Thus, the pileup and mixing of water in the littoral zone lead to an increase in biogenic elements, which may influence the phytoplankton development.
TECHNICAL SCIENCES >
The article deals with the application of complex multifractal and wavelet analysis to describe material and surface structures qualitatively and quantitatively, which allows revealing the differences poorly distinguished with other separate methods and estimating system characteristics of structures and characterizing the process of structure self-organization. The formation by tearing friction surface structures for composite materials with additives of Al2O3 and SiC is described in comparable thermodynamic conditions. Adding SiC in comparison with Al2O3 promotes to a lesser extent the fragmentation and increase in frequency of setting and breaking processes. An additional introduction of graphite in even greater degree strengthens the distinctions between materials with SiC and Al2O3 additives, which results in the formation of the least ordered structures of the friction surface. Adding graphite to a reinforced SiC composite material results in increasing the non-equilibrium of thermodynamic conditions for structure formation.
SOCIAL SCIENCES AND HUMANITIES >
ISSN 2524-2431 (Online)