D. Yu. Golovin

Electrodeposition of nickel nanoparticles onto multiwalled carbon nanotubes

The process of nickel nanoparticle nucleation and growth during galvanochemical deposition on the surface of multiwalled carbon nanotubes has been studied. The dependences of the morphology, size, and spacing of nickel nanoparticles on the deposition time at a current density of 5 and 0.5 A/dm2 are determined.

Single-domain magnetic nanoparticles in an alternating magnetic field as mediators of local deformation of the surrounding macromolecules

The forces, deformations, and stresses generated in macromolecules attached to single-domain magnetic nanoparticles under the influence of a low-frequency (nonheating) magnetic field have been analyzed analytically and numerically. It has been shown that, in bioactive macromolecules, an alternating magnetic field with an induction of 0.1–1.0 T and a circular frequency of ≲104 s−1 can induce forces up to several hundred piconewtons, absolute deformations up to a few tens of nanometers, as well as compressive and shear stresses exceeding 107 Pa. These mechanical stimuli are sufficient for a significant change of interatomic distances in active centers, conformation of macromolecules, and even a breaking of some bonds, which makes it possible to develop a new technological platform for targeted delivery of drugs, remote control of their activity, and cancer-cell destruction.

A new approach to the control of biochemical reactions in a magnetic nanosuspension using a low-frequency magnetic field

A new approach to the control of biochemical reactions in magnetic nanosuspensions exposed to a low-frequency (nonheating) magnetic field, which has a nanomechanical effect on macro-molecules chemically linked to magnetic nanoparticles (MNPs), is described. Experimental verification of this approach showed that a magnetic field with an intensity of from 15 to 220 kA/m and a frequency of 50 Hz affected the kinetics of a chemical reaction in an aqueous solution containing suspended MNPs of magnetite (FeO · Fe2O3) and chymotrypsin molecules linked to them through polymer bridges. The field dependence of the effect is shown. The effect is interpreted within the framework of a nanomechanical model taking into account the deformations, conformational change, and destruction of weak bonds in the enzyme macromolecule under the action of the forces applied to it during the orientation of MNPs in the field.

Electric thermal inspection of metal sheets

An electrothermal method of nondestructive inspection of conducting materials is proposed and tested experimentally. This method is based on filming the IR emission of the surface induced in a sheet sample excited by a millisecond current pulse. Subsequent computer processing of the nonstationary thermalfield patterns reveals millimeter and submillimeter defects and provides an opportunity to estimate their geometrical parameters and the temperature-diffusivity coefficient of the material.

Nanomechanical control of properties of biological membranes achieved by rodlike magnetic nanoparticles in a superlow-frequency magnetic field

It is proposed to use single-domain rodlike magnetic nanoparticles (MNPs) as mediators for nanomechanical control of properties of biological membranes and cells on the molecular or cellular level by exposing them to a homogeneous nonheating low-frequency magnetic field (AC MF). The trigger effect is achieved due to rotatory-oscillatory motion of MNPs in the AC MF, which causes the needed deformations in macromolecules of the membrane interacting with these MNPs.

Nonstationary Infrared Testing of Coatings on Exterior and Interior Surfaces of Metal Shells

A new method for nondestructive testing of coatings on exterior and interior surfaces of metal shells is proposed that is based on video monitoring of the infrared radiation emitted from the shell excited by shortterm external heating. Computer processing of the measured nonstationary field of temperature distribution on the outer surface allows defects with lateral dimensions on the order of or greater than the shell thickness to be revealed on the inner (inaccessible to observation) surface. Geometric characteristics of these defects can be evaluated.

Model of controlled drug release from functionalized magnetic nanoparticles by a nonheating alternating-current magnetic field

A magnetohydrodynamic model of controlled drug macromolecule release from transport magnetic nanoparticles covered by a polymer shell under the influence of a low-frequency (<1 kHz) nonheating magnetic field is described.

Classification of weakly bound ensembles of nanoparticles by determining nanomechanical characteristics

A new method for the characterization and express diagnostics of highly porous, loose, and other weakly bound media in bulk is described. This method is based on nanomechanical testing of milligram material specimens. A possibility of identifying ensembles of nanotube-containing carbon nanomaterials that have different morphologies and structures, as well as membranes that consist of polymer nanofibers, is demonstrated.