Detonation nanodiamonds: from synthesis theory to application practice

The review is devoted to the current state of research and advances in the production and study of the properties of detonation nanodiamonds (DND), their application in technology and medicine. New data on the theory and practice of DND synthesis for the last 1–5 years are considered and systematized. It is shown that the zone of chemical reactions (ZCR) during the blust of explosive materials (EM) is decisive for the fractal pre-diamond structure formation, the final region of the nanodiamonds (1/3–3/4 of the diameter of the explosive charge) formation is determined. The possibility of predicting the DND yield and the influence of parameters on the synthesis process of nanodiamonds from individual EMs of binary and ternary compositions is shown, their optimal formulations are determined. The optimal ZCR width and the existence time of chemical reactions have been identified. The dependence of the DND yield on the nitrogen content in the EM was shown. The most effective method of DND purification and the possibility of obtaining graphite-diamond compositions of a given formulation are presented. The most informative indicators of nanodiamonds characterization are given. The magnetic properties of nanodiamonds are considered and the identity of the properties of DNDs from different EMs is shown. The characteristics of new compositions based on DND are indicated: electrochemical coatings (gold and chromium-diamond), thermal pastes, diamond-containing polymer filaments for a 3D printer, fuel compositions, enterosorbents, compatible with biosystems of the nanodiamond-drug composition.

Graphene breakthrough into future technology: the 2010 Nobel Prize in Physics Laureate Sir Konstantin Sergeevich Novoselov

The paper explores the research work of one of the youngest winners of the 2010 Nobel Prize in Physics, Konstantin Sergeevich Novoselov (born 23.08.1974). Since 2004 when the single-atom graphene was extracted and the research findings were published for the first time, the graphene breakthrough has been made. The paper focuses on the main milestones of Novoselov’s biography and analyzes his publishing activity between 2004 and 2018. The data confirming the highest number of citation of Novoselov’s publications in the world’s leading scientific journals are presented. Novoselov’s main scientific awards are listed.

Studies of the pore space of the UPM-K, UAM-50, UAM-100 composite ultrafiltration membrane

The development of methods for assessing the distribution of pores by radii (or diameters) and studying the microstructure of the surface of a membrane partition is an urgent task. The authors of the paper carried out experimental studies of the pore diameter distribution for the UPM-K ultrafiltration membrane, determined the porosity and hydrodynamic permeability of the UAM-50, UAM-100 membranes. The analysis of the experimental results showed that the UPM-K ultrafiltration membrane had an average pore diameter of 54 nm. The UAM-50 and UAM-100 membranes were characterized by an asymmetric structure (an active layer (dense) and a porous substrate), while the pores were 2.5–40 and 10–40 nm in size, respectively. The experiments on the study of the hydrodynamic permeability of UAM-50, UAM-100 ultrafiltration membranes when separating a solution of sodium lauryl sulfate showed that the kinetic response curves of the “membrane-solution” system were conventionally divided into two stages. The first stage of the process was faster and lasted only a few minutes. After 7.8 and 13.05 min, the hydrodynamic permeability decreased by ~ 27 %, 7 %, which was due to structural changes in the cellulose acetate layer under the action of mechanical load (transmembrane pressure). The second stage was slower – with a duration of ~ 33 and 60 min and a decrease in hydrodynamic permeability by 41 % and 11 %. Based on the analysis of the approximating function, the rate constants of the membrane separation of solutions and the empirical coefficients of the equation are found.

Anthracite-based activated carbons for the efficient solution of important environmental problems

This article examines the issues of environmental pollution as a result of man-made activities and determines the most effective ways to protect the biosphere with the help of carbon-adsorption technologies. Due to their physical and chemical properties, activated carbons are an ideal adsorbent and allow solving a wide range of environmental safety issues. Based on the theoretical assumptions expressed by Academician M. M. Dubinin, it is shown that anthracite is an excellent raw material for producing activated coal. A technology for obtaining СAS (Crushed Anthracite Sorbent) grade activated carbons from anthracite has been developed and its adsorption properties have been studied. Tests of СAS activated carbon in the purification of drinking water and wastewater, protection of the atmosphere from harmful gases and vapors, and detoxification of soils from herbicide residues were carried out. The necessity and requirements for the creation of new production facilities for active coals based on anthracite in Russian coal basins are substantiated.

High resolution transmission electron microscopy analysis of conical carbon nanotubes formed in the high isostatic pressure apparatus

Carbon nanotubes with “herringbone” layers structure synthesized in high isostatic pressure apparatus were studied by High Resolution Transmission Electron Microscopy (HRTEM) methods. Seven different values of semi-apex angles of graphene layers were observed in different nanotubes. It is shown that semi-apex angles approximately equal to 5, 15, 25 и 35 can be regarded only to the scroll structure of the nanotubes, while 10, 20 and 30 can be regarded to both scroll either nested graphene layers curved to cones due to the embedding of the pentagon’s to them. Thus, the observation of all (seven) of these values of semi-apex angles testifies presence of scroll nanotubes in the sample under study, though it does not exclude presence of nested-cone nanotubes.

Design of mechatronic engineering systems in digitalized traditional and additive manufacturing

The paper presents the analysis of the steps and stages of designing process equipment for traditional manufacturing. The features of building process equipment using energy flows and consumables are studied. Structural synthesis of mechatronic systems in digitalized manufacturing make it possible to add new stages to the process of creating process equipment for both traditional automated subtractive and new additive manufacturing. The processes of manufacturing parts without forming equipment described by the algorithms according to the proposed structural diagram of connections provide an opportunity to analyze the existing equipment and develop new equipment for laminate synthesis of products. The paper illustrates the use of methods and procedures for laminate synthesis and fabrication of parts from composite materials using process equipment based on the application of energy flows and material components for new additive and traditional subtractive manufacturing. Also, methods and diagrams for automation and computer-aided process control over product manufacturing are shown.

Geo-ecological characteristics of the small lakes bottom sediments in the North of Western Siberia

The article analyzes and provides data on the processes of accumulation of heavy metals by bottom sediments from the point of view of environmental assessment. The purpose of this paper is to identify the degree of anthropogenic influence on the lakes of the Tazovskiy and Surgut districts, and assess the ecological state of water bodies and adjacent territories. The main processes occurring in natural reservoirs, which lead to the transfer of toxicants into the environment, are considered. The data of quantitative chemical analysis of bottom sediments of two groups of natural reservoirs with an assessment of their ecological state according to the results of statistical processing of the measured values were obtained. Excess concentrations of metals were recorded: for mobile forms – 2200 times for Fe, 1050 times for Mn, 35 times for Cr, 20 times for Co, up to 15 times for Ni, 5 times for Cu, 3 times for Pb, for acid-soluble forms – 45 000 times for Fe, 550 times for Pb, up to 75 times for Ni, 525 times for Mn, 105 times for Cr, 50 times for Cu, 16 times for Co. The geochemical interpretation of the results of the factor analysis is presented.

Generation of high-intensity ultra-short optical pulses: 2018 Nobel Prize Winners in Physics Gerard Mourou and Donna Strickland

In the early 1980s, French physicist G. Mourou and his Canadian collaborator D. Strickland solved the problem of power drop by dispersing in time and space the processes of amplification and compression: a method of obtaining super-powerful chirped laser pulses (CPA – chirped pulse amplification). The paper presents brief biographical references to Mourou and Strickland. The 2018 Nobel Prize in Physics was awarded “for groundbreaking inventions in the field of laser physics”: Artur Isidorovich Ashkin (Ashkinazi, born 02.09.1922, USA), half of the prize “for the optical tweezers and their application to biological systems”; Gerard Albert Mourou and Donna Theo Strickland (became the third woman to be awarded the Nobel Prize in Physics) (quarterly premium) “for their method of generating high-intensity, ultra-short optical pulses”. Since that time all lasers have been built on a new principle: after the amplifiers place a compressor from diffraction bars. Instead of simply amplifying the pulse, it is first spread out on spectral components spread over time, then they are amplified separately, then again assembled into a single pulse. At each point in time, only a fraction of the pulse is amplified, not the entire pulse, allowing for a much higher peak intensity of laser light flow.

The effect of Dzyaloshinskii–Moriya interaction on direct and backward transition between magnetic states of Pt/Co/Ir/Co/Pr synthetic ferrimagnet

In this paper, we present the study of domain structure accompanying interstate transitions in Pt/Co/Ir/Co/Pr synthetic ferrimagnet (SF) of 1.1 nm thick and 0.6 – 1.0 nm thin ferromagnetic Co layers. Variation in the thickness of the thin layer causes noticeable changes in the domain structure and mechanism of magnetization reversal revealed by MOKE (Magneto-Optical Kerr Effect) technique. Magnetization reversal includes coherent rotation of magnetization of the ferromagnetic layers, generation of magnetic nuclei, spreading of domain walls (DW), and development of areas similar with strip domains, dependently on thickness of the thin layer. Inequivalence of the direct and backward transitions between magnetic states of SF with parallel and antiparallel magnetizations was observed in sample with thin layer thicknesses 0.8 nm and 1.0 nm. Asymmetry of the transition between these states is expressed in difference fluctuation fields and shapes of reversal magnetization nucleus contributing to the correspondent forward and backward transitions. We proposed simple model based on asymmetry of Dzyaloshinskii–Moriya interaction. This model explains competition between nucleation and domain wall propagation due to increase/decrease of the DW energy dependently on direction of the spin rotation into the DW in respect to external field.

A study of the structure and morphology of the graphite electrochemical exfoliation products

The paper presents a generalized analysis of the results of scanning electron microscopy, energy dispersive spectroscopy, and TG/DSC analysis of electrochemical exfoliation products from two types of initial graphite raw materials at different process temperatures in solutions of potassium hydroxide (KOH) and sulfuric acid (H2SO4). It is shown that an increase in the concentration of an alkaline electrolyte in the range from 0.1 to 1.0 molL–1 promotes the intensification of the process of separation and splitting of graphite into fragments. In the case of the formation of large fragments, the product contains a significant amount of intercalated potassium ions, which are not removed when the material is washed off. The products of electrochemical exfoliation of the spent electrocontact graphite material demonstrate structural heterogeneity, contain a significant amount of functional groups and impurities of the amorphous phase. Thermogravimetric curves have several sections of sample weight reduction. After heating these materials in an inert atmosphere to 900 °C, the total weight loss reaches 66 %. From a thermally expanded graphite foil, samples of nanographites, extremely homogeneous in chemical composition, with increased thermal stability and a minimum number of surface defects were obtained. The total weight loss of the samples when heated in an inert atmosphere to 900 °C does not exceed 17 %. It was shown that the replacement of an alkaline electrolyte with a sulfuric acid solution leads to an increase in the number of defects in the product.