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In this article, the expected resources of copper scrap in the Russian Federation have been analyzed, and their amounts and use through 2035 have been estimated. The conclusion on reducing the supply of copper scrap resources in the country in the mid-term prospects as a result of the change in based on the scrap generation and notable decline in the copper consumption in the country since the 1990s has been explained. In addition, the possible presence of uncollected scrap reserves, which may ultimately affect the operations of producers of copper and copper-containing products and lead to increased competition over the raw materials on the market, has been assessed and analyzed.

The analysis of biological data is a key topic in bioinformatics, computational genomics, molecular modeling, and systems biology. The methods covered in this article can reduce the cost of experiments aimed at obtaining biological data. The problem of the identifiability of mathematical models in physiology, pharmacokinetics, and epidemiology is considered. The processes considered are modeled using nonlinear systems of ordinary differential equations. The mathematical modeling of dynamic processes is based on the use of the mass conservation law. The problem of estimating the parameters characterizing the process under study raises the question of nonuniqueness. When the input and output data are known, it is useful to perform an a priori analysis of the relevance of these data. The definition of the identifiability of mathematical models is considered. Methods for the analysis of the identifiability of dynamic models are reviewed. In this review article, the following approaches are considered: the transfer function method applied to linear models (useful for the analysis of pharmacokinetic data, since a large class of drugs is characterized by linear kinetics); the Taylor series expansion method applied to nonlinear models; the differential algebra methods (the structure of this algorithm allows it to be run on a computer); and a method based on graph theory (this method allows for the analysis of the identifiability of the model and finding a proper reparametrization reducing the initial model to an identifiable one). The need to perform a priori identifiability analysis before estimating the parameters characterizing any process is demonstrated with several examples. The examples of identifiability analysis of mathematical models in medical biology are presented.

The blazing ability of multilayer-coated blazed gratings (MBGs) was systematically investigated via numerical calculation of the diffraction efficiency with a rigorous electromagnetic simulation code. It was found that the blazing condition is not exact and allows significant deviation from the ideal situation for ultra-dense MBGs. A mismatch of the interfaces of the multilayer (ML) stacks of adjacent grooves results in a modified effective blaze angle, which gives the opportunity to control and tune precisely the blaze angle via a proper choice of ML d-spacing. Also this allows a new kind of x-ray gratings that have a variable line spacing (VLS) as well as a variable blaze angle. Precise adjustment of a local blaze angle of a VLS MBG can be achieved with a laterally graded ML, providing very high diffraction efficiency for the whole area of the grating.

Imperfections in the multilayer stack deposited on a saw-tooth substrate are the main factor limiting the diffraction efficiency of extreme ultraviolet and soft x-ray multilayer-coated blazed gratings (MBGs). Since the multilayer perturbations occur in the vicinity of antiblazed facets of the substrates, reduction of the groove density of MBGs is expected to enlarge the area of unperturbed multilayer and result in higher diffraction efficiency. At the same time the grating should be optimized for higher-order operation in order to keep high dispersion and spectral resolution. In this work we show the validity of this approach and demonstrate significant enhancement of diffraction efficiency of MBGs using higher-order diffraction. A new record for diffraction efficiency of 52% in the second diffraction order was achieved for an optimized MBG with groove density of 2525  lines/mm at the wavelength of 13.4 nm.

Periodic and aperiodic Sb/B4C multilayer structures have been theoretically calculated and synthesised for the first time for the application in soft X-ray optics in the 80 A < l < 120 A range. The reflection spectra of the periodic multilayer mirrors are measured using synchrotron radiation and laser plasma-generated radiation. The experimental spectra are theoretically interpreted with the inclusion of transition layers and substrate roughness. The density of antimony layers is supposedly r(Sb) = 6.0 g cm-3, and the thickness of transition layers (if any) in the Sb/B4C multilayer structures does not exceed 10 A. A peak reflectivity of 19 % is attained at a wavelength of 85 A. An aperiodic mirror optimised for maximum uniform reflectivity in the 100 - 120 A range is tested employing the laser plasma radiation source.

Impact of Ar gas pressure (1-4 mTorr) on the growth of amorphous interlayers in Mo/Si multilayers deposited by magnetron sputtering was investigated by small-angle x-ray scattering (=0.154 nm) and methods of cross-sectional transmission electron microscopy. Some reduction of thickness of the amorphous inter-layers with Ar pressure increase was found, while composition of the layers was enriched with molybdenum. The interface modification resulted in raise of EUV reflectance of the Mo/Si multilayers.

Diffraction gratings with high efficiency and high groove density are required for EUV and soft x-ray spectroscopy techniques (such as Resonant Inelastic X-ray Scattering, RIXS) designed for state-of-the-art spectral resolution and throughput. A multilayer coated blazed grating (MBG) fabricated by deposition of a multilayer on a saw-tooth substrate could address these challenges. In order to obtain high diffraction efficiency one should provide perfect triangular grooves on a substrate and perfect replication of the groove profile during the multilayer deposition. However, multilayers trend to smooth out the corrugated surface of the substrates, resulting in the main limiting factor for efficiency of ultra-dense MBGs. Understanding of the growth of multilayers on saw-tooth substrates is a key for further grating improvement. In this work we investigate growth behavior of Al/Zr multilayers on saw-tooth substrates with a groove density of 10,000 lines/mm. We apply existing growth models to describe an evolution of Power Spectral Density functions of a grating surface during the multilayer deposition, and identify a main smoothing mechanism. We found that growth of flat multilayers is well modeled with surface diffusion caused by surface curvature as a main relaxation mechanism, while growth of the multilayer on saw-tooth substrates obeys different kinetics. Limitations of the linear approach and possible model improvements by accounting for an additional component of the surface diffusion flux, caused by a gradient of adatom concentration on a corrugated surface are discussed.

Early cleavages of the marine nematode Enoplus brevis are symmetrical and occur in synchrony. At the 2- to 16-cell stages, blastomeres are indistinguishable. The progeny of blastomeres was investigated by intracellular injections of fluorescent dyes and horse radish peroxidase. One blastomere of the 2-cell embryo gives rise to a compact group of cells occupying about half of an embryo. The border between labeled and unlabeled cells differs in each embryo dividing it to anterior-posterior, left-right or intermediate parts. At the 8-cell stage, one blastomere gives rise to only endoderm, whereas the other blastomeres produce progeny that form multiple cell types, including nerve, muscle and hypoderm cells, in various proportions. Thus the fates of the blastomeres of early E. brevis embryos, with the exception of the endoderm precursor, are not determined. The process of gastrulation in E. brevis is very similar to that in Caenorhabditis elegans and other nematodes. At the beginning of gastrulation, the 2-celled endoderm precursor lies on the surface of embryo and then sinks inwards. After labeling of cells on the ventral side (near endoderm precursor) at the beginning of gastrulation, their progeny differentiate predominantly into body muscles or pharyngeal cells of the first stage larva. Cells that are located more laterally give rise mainly to neurons. The dorsal blastomeres differentiated principally into hypoderm cells. Our study suggests that a precise cell lineage is not a necessary attribute of nematode development.

Diffraction efficiency of multilayer-coated blazed gratings (MBG) strongly depends on the perfection of the sawtooth-shaped layers in the overall composite structure. Growth of multilayers on sawtooth substrates should be carefully optimized to reduce groove profile distortion and, at the same time, to avoid significant roughening of multilayer interfaces. In this work, we report on a way to optimize growth of sputter-deposited Mo/Si multilayers on sawtooth substrates through variation of the sputtering gas pressure. We believe a new record for diffraction efficiency of 44% was achieved for an optimized MBG with groove density of 5250  lines/mm at the wavelength of 13.1 nm.

The damage threshold and damage mechanism of extreme-ultraviolet Sc/Si multilayer mirror coatings are investigated with focused nanosecond pulses at 46.9-nm radiation from a compact capillary-discharge laser. Damage threshold fluences of ∼0.08 J/cm^2 are measured for coatings deposited on both borosilicate glass and Si substrates. The use of scanning and transmission electron microscopy and small-angle x-ray diffraction techniques reveals the thermal nature of the damage mechanism. The results are relevant to the use of newly developed high-flux extreme-ultraviolet sources in applications.

The paper presents a metallographic investigation of samples of high-speed steel and structural steel with hard alloy coatings applied by electro-spark alloying. Metallographic investigation shows that there is a transition layer between the samples and their coatings where impurities of an electrode alloy material in the structure of the base material can be detected. This indicates that the technological process of the coating is accompanied by diffusion of the materials of the cathode and anode in the transition layer. Microhardness testing shows that the coating can be divided into two layers. The top layer consists of a reinforcing material of the electrode and the base material. It has high hardness, which decreases with the penetration of the coating into the sample because the coating and the base material is mixed. Also, there is the second transition layer, which has hardness lower than the hardness of the base material, i.e., in fact, a secondary temper layer. This layer is a result of high temperature exposure of the process of hardening. Metallographic investigation shows that physical-mechanical properties of the coating can be controlled by varying coating mode.

The paper presents a metallographic investigation of samples of high-speed steel and structural steel with hard alloy coatings applied by electro-spark alloying. Metallographic investigation shows that there is a transition layer between the samples and their coatings where impurities of an electrode alloy material in the structure of the base material can be detected. This indicates that the technological process of the coating is accompanied by diffusion of the materials of the cathode and anode in the transition layer. Microhardness testing shows that the coating can be divided into two layers. The top layer consists of a reinforcing material of the electrode and the base material. It has high hardness, which decreases with the penetration of the coating into the sample because the coating and the base material is mixed. Also, there is the second transition layer, which has hardness lower than the hardness of the base material, i.e., in fact, a secondary temper layer. This layer is a result of high temperature exposure of the process of hardening. Metallographic investigation shows that physical-mechanical properties of the coating can be controlled by varying coating mode.

The concept of the mean value of a function is used to interpret some population-dynamics equations. The well-known formula for the per capita growth rate r gives a precise mean value for any (not only exponentially growing) populations. This result is used to derive the birth and death rate equations of Paloheimo (1974) with minimal initial limitations.