Corrosion-resistant composite coatings on biodegradable magnesium alloys: In vitro studies

A composite coating was formed on MA8, MA14, and MA12 magnesium alloys by plasma electrolytic oxidation with subsequent immersion of samples into a superdispersed polytetrafluoroethylene suspension. In vitro volumetry determined that using this coating significantly reduces the magnesium alloy dissolution rate. It was shown that superdispersed polytetrafluoroethylene seals pores of the coating, thus reducing the corrosion rate in an artificial medium that mimics human blood by ionic composition. However, the surface of the calcium phosphate coating (Ca: P = 1.61) containing hydroxyapatite remains open for contact with the environment. The obtained data suggested that the proposed method for surface treatment of MA8, MA14, and MA12 alloys is promising for producing biodegradable protective coatings on magnesium medical implants.     

Synthesis of cinnoline 1-oxides by the reaction of ortho-fluoronitrobenzenes with enediamines

Reaction of α-carbonylacetamidines existing in the enediamine tautomeric form with the substituted ortho-fluoronitrobenzene afforded products of the replacement of the fluorine by the α-C atom of amidine. The latter underwent cyclization into cinnoline 1-oxides on treatment with sodium hydride.     

The influence of a fluoroorganic modifier—stillage residues of alcohol-telomeres—on properties of filled poldienurethanes

The results of an investigation of the influence of stillage residues of polyfluorinated alcoholtelomeres on the properties of polydienurethane compositions and elastomers based on them are presented. It is shown that such modification allows one to raise the sedimentation stability of the compositions and increase the characteristics of physicochemical and dynamic properties of elastomers.     

Structure,Phase Composition and Properties of Rail Running Surface at Extremely Long Operation Time

Russian Physics Journal - The paper presents investigations of the structure, phase composition and properties of the rail running after bulk steel hardening. Investigations are performed at a...     

New Spin Probes: Tri- and Hexacationic Derivatives of Stable Tetrathiatriarylmethyl Radicals

Russian Journal of Organic Chemistry - The reaction of Finland trityl with tertiary aliphatic alcohols containing a terminal tertiary amino group, followed by quaternization of the amino groups,...     

Asymptotic Behavior of Solutions in Finite Difference Schemes

Many problems of numerically solving the Schrödinger equation require that we choose asymptotic distances many times greater than the characteristic size of the region of interaction. If the solution to one-dimensional equations can be immediately chosen in a form that preserves unitarity, the invariance of probability (in the form of, e.g., fulfilling an optical theorem) is a real problem for two-dimensional equations. An addition that does not exceed the discretization error and ensures a high degree of unitarity is proposed as a result of studying the properties of a discrete two-dimensional equation.     

Reconstruction of the Sea Bottom Parameters for Coherent Seismoacoustic Sounding: I. Decision Rules

We have developed an algorithm for reconstructing the geoacoustic parameters of bottom layers using parametric models of the formation of signals reflected from a layered halfspace during coherent sounding of the bottom of a sea shelf. We propose a method for layer-by-layer reconstruction that makes it possible to efficiently search for a solution in the multiparameter space with limited a priori data.     

Plasma Synthesis and XPS Attestation of Thin-Film Carbon Coatings with Predetermined sp-Hybridization

Physics of Atomic Nuclei - The diversity of carbon materials has allowed them to be used for fundamental and applied research to date. The newest modifications of carbon, such as nanodiamonds,...