Formation of silver nanoparticles from a complex of Ag(I) with 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid in organic solvents

Specific features of the formation of silver nanoparticles upon the decomposition of the complex of Ag(I) with 2-[4,6-di(tert-butyl)-2,3-dihydroxyphenylsulfanyl]acetic acid in organic solvents characterized by large donor numbers (27–34) are studied. It is established that the stability of prepared organosols depends to a significant extent on the nature of a dispersion medium and the presence of water and oxygen in this medium. The Ag(I) complex is a solid precursor for the preparation of silver nanoparticles.     

Influence of Cobalt Intercalation on Processes in a Nickel-Zinc Battery with Nickel Oxide Electrode Fabricated from Spherical Nickel Hydroxide

The influence of cobalt on processes that occur in a nickel oxide electrode of a nickel-zinc battery, fabricated from spherical nickel hydroxide on foamed nickel support, was studied.     

Reaction of <Emphasis Type="Italic">N,N</Emphasis>′-bis(trimethylsilyl)dicyandiamide with bis(η<Superscript>5</Superscript>-cyclopentadienylvanadium) dichloride

1,3,5-Tris[bis(η⁵-cyclopentadienyl)chlorovanadium]melamin is prepared in high yield by the reaction of N,N′-bis(trimethylsilyl)dicyandiamide with bis(η⁵-cyclopentadienylvanadium) dichloride in tetrahydrofuran. As side products, trimethylchlorosilane and cyclopentadiene formed. Reaction of N,N′-bis(trimethylsilyl) dicyandiamide with benzoyl chloride results in the formation of tris(benzoyl)melamin.     

Epoxy and polyurethane adhesive materials of elad,aquapol, and acrolat brands and their components

Different groups of chemical products developed and produced at the Macromer Scientific and Manufacturing Company are described and recommended for use in adhesive compositions, including reactive diluents for epoxy compositions, urethane prepolymers, binders for photocurable materials, aqueous polyurethane dispersions. The main characteristics of binders for glues are presented, as well as the prospects for their application in formulas of adhesive compositions.     

Solubilization of Aliphatic Carboxylic Acids (C3-C6) by Sodium Dodecyl Sulfate and Brij 35 Micellar Pseudophases

The apparent dissociation constants of 1-propanoic, 1-butanoic, 1-pentanoic and 1-hexanoic acids were obtained for the first time in Brij 35 micellar solutions with concentration from 0.03 to 0.20 mol⋅L⁻¹ and sodium dodecyl sulfate (SDS) micellar solutions with concentrations from 0.01 to 0.30 mol⋅L⁻¹. A pronounced effect of Brij 35 micelles on the acid-base properties of aliphatic acids was observed. The binding constants, K _b, of carboxylic acids to micellar pseudophases of SDS and Brij 35 were estimated within the framework of the pseudophase model. The dependences of Gibbs energies of transfer from water to the micellar pseudophases were constructed, and Gibbs energies were evaluated for methylene and carboxylic group transfers into Brij 35 and SDS micelles. Comparison of the Gibbs energies of methylene group transfer from water to Brij 35 and SDS suggests that the mechanisms of hydrocarbon group transfer into the core of nonionic and anionic micelles involving the same monomer hydrophobic tail length are similar.     

Conservative finite-difference scheme for computer simulation of contrast 3D spatial-temporal structures induced by a laser pulse in a semiconductor

The numerical approach for computer simulation of femtosecond laser pulse interaction with a semiconductor is considered under the formation of 3D contrast time-dependent spatiotemporal structures. The problem is governed by the set of nonlinear partial differential equations describing a semiconductor characteristic evolution and a laser pulse propagation. One of the equations is a Poisson equation concerning electric field potential with Neumann boundary conditions that requires fulfillment of the well-known condition for Neumann problem solvability. The Poisson equation right part depends on free-charged particle concentrations that are governed by nonlinear equations. Therefore, the charge conservation law plays a key role for a finite-difference scheme construction as well as for solvability of the Neumann difference problem. In this connection, the iteration methods for the Poisson equation solution become preferable than using direct methods like the fast Fourier transform. We demonstrate the following: if the finite-difference scheme does not possess the conservatism property, then the problem solvability could be broken, and the numerical solution does not correspond to the differential problem solution. It should be stressed that for providing the computation in a long-time interval, it is crucial to use a numerical method that possessing asymptotic stability property. In this regard, we develop an effective numerical approach—the three-stage iteration process. It has the same economic computing expenses as a widely used split-step method, but, in contrast to the split-step method, our method possesses conservatism and asymptotic stability properties. Computer simulation results are presented.     

Calcium thorium phosphate (Whitlockite-type mineral). Synthesis and structure refinement

The crystal structure of a new calcium thorium phosphate has been refined by the full-profile Rietveld method using X-ray powder diffraction data. The sample has been synthesized by the sol-gel technique. The phosphate has been identified by X-ray powder diffraction and IR spectroscopy. The refined composition is represented by the formula Ca_10.26Th_0.12(PO₄)₇. The CaO _n and PO₄ polyhedra are distorted compared to the corresponding polyhedra in the basic compound β-Ca₃(PO₄)₂.