Nanotechnologies in Russia最新文献

To compensate for thermal stresses in high-temperature thermoelements (TEs), contact systems (CSs) are developed. These CSs contain nanocomposite damping layers formed by an array of carbon nanotubes (CNTs), in which the channels are partially filled with metal with high electrical conductivity. The CNTs are obtained by catalytic chemical vapor deposition using buffer layers based on Ti–Ni or Co–Nb–N. CNTs up to 7 μm thick are synthesized at a temperature of 700°C for 2 min. In the CSs, a Ni comutation layer up to 15 μm thick is formed on the surface of the CNTs by chemical or electrochemical deposition. Ni is deposited directly onto the CNT surface or onto a preliminarily sputtered Ni layer with a thickness from 100 to 500 nm. As a result, the TE legs with CSs are thermally stable up to 600°C. The CSs have a high adhesion strength up to 9.7 MPa and low specific contact resistance of about 10^–9 Ω m².

The characteristics of synthetic antiferromagnetic (SAF) nanostructures CoFeB/Ru/CoFe with a Ru layer thickness corresponding to the second antiferromagnetic (AF) maximum are obtained. The magnetization-reversal curves of SAF structures with a Ru thickness of 2.1, 2.3, and 2.5 nm are studied. The magnetization-reversal curves of CoFeB/Ru/CoFe structures under conditions of their fixation by an AF layer are presented. In addition, the magnetization-reversal curves of spin-tunnel magnetoresistive nanostructures with an AF layer and a SAF structure are presented, and an analysis of the thermal stability of structures with SAF is carried out.

Therapeutic agents based on monoclonal antibodies (mAbs) are successfully used in the diagnostics and treatment of a wide range of infectious and autoimmune diseases, as well as in the combating malignancies. Due to their high specificity, mAbs are used to target signalling or acting agents to a cell of interest in vivo. Thus, radioactively labelled antibodies are among important tools in nuclear medicine. Stringent control of the conformational integrity and aggregation stability of the mAb preparation is critical for successful biotherapeutic development. In this study, we describe the application of nanodifferential scanning fluorimetry (nanoDSF) to obtain a radioactively labelled monoclonal antibody (¹⁶¹Tb-DOTA-mAb). Using this method, we optimized the procedure of DOTA-mAb conjugate preparation and determined the storage conditions suitable for subsequent rapid radionuclide labelling of the conjugate.

A hypothesis, according to which a charged nanobubble in water with an energetically favorable structure is surrounded by a hydrate layer ~1 nm thick with a permittivity equal to ~3, on top of which a diffuse layer is placed, is energetically substantiated. This reduces the capacity of the nanobubble and increases its Coulomb pressure, for example, by 10 times at a radius of 4 nm, counteracting the Laplace pressure and stabilizing the nanobubble. A formula is given for approximating the pressure increase factor with an error of 20% at r₀ = 5–60 nm.

The change in the electrical characteristics of LED structures based on InGaN/GaN caused by high current flow in the pulsed mode is investigated. Stable switching between high-conductive (resistive) and low-conductive (light-emitting) states is discovered, which is accompanied by a change in current transfer mechanisms. The main switching mechanism is considered to be the movement of mobile defects and the formation of conductive filaments (channels) in the space-charge region.

The aim of this study is to develop nanomaterials based on porous frameworks for the targeted delivery of active compounds. Three metal-organic frameworks (MOFs) ZIF-8, UiO-66-NH₂, and MIL-100(Fe) are coated with surfactants (SAs) to enhance their bioavailability. The stability of MOFs during modification with SA solutions is studied. Based on data from powder X-ray diffraction and IR spectroscopy, the optimal MOF–SA pairs are identified. The adsorption and desorption dynamics of cationic (methylene blue) and anionic dyes (methyl orange) by the most promising composites are investigated. The obtained results and proposed patterns can be further used for loading active components, such as phytohormones, into MOF pores, considering the specifics of electrostatic interactions and potential binding via functional groups.

The interaction of water with air-dried membrane films and precursors of Nafion and Aquvion type membranes was investigated. The differential scanning calorimetry studies demonstrated the presence of free water in the films that was trapped at the stage of sample preparation. The dielectric spectroscopy results revealed two relaxation processes associated with the mobility of functionalized substituents in the polytetrafluoroethylene main chain for the polymers in the sulfonic acid form, with activation energies ranging from 12.9 to 33 kcal/mol, which indicates the “cooperativity” of local processes. The activation energies vary depending on both the length of a substituent and the distance between two neighboring substituents (the polymer chain parameter n). It was demonstrated by wide-angle X-ray scattering that an increase in the polymer chain parameter leads to an increase in the degree of crystallinity of Nafion copolymers in the sulfonyl fluoride form. The presence of “water-polymer” and “water-water” associates, as well as non-associated water molecules, was shown by infrared spectroscopy.

The features of the interaction of individual impurity-free nickel nanoparticles deposited onto the surface of highly oriented pyrolytic graphite, differing in terms of their geometric dimensions, with nitrous oxide (N₂O) are studied. It is found that the results of exposing the samples to N₂O depend on the nanoparticle shape and size. The surface of nickel nanoparticles with a height of 4–5 nm or more undergoes oxidation, while nickel nanoparticles with a height of up to 2 nm remain oxide free.

This paper presents for the first time the results of studying the influence of annealing modes of GaAs(111) substrates modified by focused ion beams on the transformation of the geometric characteristics of formed nanoholes due to the processes of local droplet etching. Experimental regularities of the influence of the number of ion beam passes, as well as the modes of substrate annealing (in an arsenic flux or its absence) on the shape, depth, and lateral size of nanoholes are established. The mechanism of transformation of the geometric characteristics of nanoholes formed at the points of influence of a focused ion beam during annealing under different modes leading to local droplet etching of the substrate at varying intensities is proposed.

The work briefly discusses: the development of photonic neural networks for artificial intelligence (AI) and the principles of their construction and stages of development. The types of training of AI neural networks, the advantages of such networks, as well as the scope of their application for creating more efficient AI systems based on the photonic approach are described.