To evaluate the effect of yield stress on hydrogen embrittlement (HE) of martensitic and ferritic steels, the effect of hydrogen (H) capture by structural inhomogeneities (hydrogen traps) and the effect of plastic deformation and stress on the mechanism of stress corrosion cracking (SCC) are considered. In the presence of hydrogen, the brittle fracture of high-strength martensitic steels consists of flat areas of intergranular fracture at the initial austenitic grain boundaries and quasi-brittle cracks at the boundaries of martensite blocks. In low-strength steels, brittle fracture manifests itself in the form of transgranular fracture of ferrite grains. The decrease in the characteristics of martensitic steels with an increase in the yield strength occurs due to an increase in the hydrogen concentration at the stage of anodic dissolution (AD) due to the growth of the carbide/matrix interface. The reason for the growth hydrogen concentration in ferritic steels is a large mechanical overstress, an increase in the number of active dissolution centers, the formation of an electrochemical pearlite-ferrite pair, and an increase in surface roughness with increasing deformation. It is concluded that the bell-shaped dependences of the critical stress of the transition from AD to SCC and other characteristics of mechanical tests on magnitude of the yield stress are due to different mechanisms of hydrogen accumulation in martensitic and ferritic steels.

The features of diffusion in two-phase (duplex) stainless steel (DSS), interaction the effect of hydrogen with trap sites in various steel structures, the influence of plastic deformation, local stresses and hydrogen concentrations on localized corrosion and hydrogen embrittlement Available data indicate that the diffusivity of DSS is insensitive to plastic deformation and increase in dislocation density, but it is influenced by grain boundaries and interfaces α/γ-phases The influence of hydrogen on stability is considered γ-phases, formation of second phases and hydrogen trap semi-coherent grain boundaries. The mechanisms that ensure crack propagation are discussed: brittle, associated with decohesion in the region of maximum hydrostatic stress, and plastic in the austenite phase—due to shear decohesion along the slip plane. Reviewed the influence of the yield stress of duplex steel on the susceptibility to hydrogen embrittlement, as well as on correlation of the steel embrittlement index with the total amount of absorbed hydrogen.

The success of genomic sequencing is impossible without the development of information technologies and mathematical methods for data processing to establish various characteristics of the analyzed objects (nucleic acids) and trends in their variation. The volume of experimental data from studying the genome has substantially increased, and new methods and algorithms are required for their processing. The evaluation of the parameters of images obtained from video cameras in the form of electrical signals is a primary step in processing the data from devices for genomic parallel sequencing. The next stage of processing is the construction of a nucleotide sequence according to algorithms that depend on the operation principle of a device for sequencing nucleic acids. Algorithms for assessing quality scores in all individual reads are important in this stage. The use of algorithms based on the analysis of k-mers is one of the ways to assess the quality score. Calculation of the number of occurrence of k-mers during the experiment on a parallel sequencing system makes it possible to assess the reliability of the analysis. In this paper, algorithms for processing data of a genetic analyzer are reviewed.

The success of genomic sequencing is impossible without the development of information technologies and mathematical methods for data processing to establish various features in the analyzed objects (nucleic acids) and trends in their changes. The volume of experimental data in the research of the genome has grown significantly, and new methods and algorithms are required for their processing. The primary stage of processing the data of devices for genomic parallel sequencing is the evaluation of the parameters of images obtained from video cameras in the form of electrical signals. The next stage of processing is the construction of a sequence of nucleotides according to algorithms that depend on the principle of operation of the device for sequencing nucleic acids. When performing this stage, algorithms for evaluating quality indicators for all individual readings (reads) are important. One of the ways to assess quality is to use algorithms based on the k-measure analysis methodology. The calculation of the number of occurrences of k-measures during the experiment on the parallel sequencing system makes it possible to assess the reliability of the analysis. In this article, algorithms for processing genetic analyzer data are considered.

To evaluate the effect of yield stress on hydrogen embrittlement (HE) of martensitic and ferritic steels, the effect of hydrogen (H) capture by structural inhomogeneities (hydrogen traps) and the effect of plastic deformation and stress on the mechanism of stress corrosion cracking (SCC) are considered. In the presence of hydrogen, the brittle fracture of high-strength martensitic steels consists of flat areas of intergranular fracture at the initial austenitic grain boundaries and quasi-brittle cracks at the boundaries of martensite blocks. In low-strength steels, brittle fracture manifests itself in the form of transgranular fracture of ferrite grains. The decrease in the characteristics of martensitic steels with an increase in the yield strength occurs due to an increase in the hydrogen concentration at the stage of anodic dissolution (AD) due to the growth of the carbide/matrix interface. The reason for the growth hydrogen concentration in ferritic steels is a large mechanical overstress, an increase in the number of active dissolution centers, the formation of an electrochemical pearlite-ferrite pair, and an increase in surface roughness with increasing deformation. It is concluded that the bell-shaped dependences of the critical stress of the transition from AD to SCC and other characteristics of mechanical tests on magnitude are due to different mechanisms of hydrogen accumulation in martensitic and ferritic steels.

The influence of metallurgical factors on stress corrosion cracking of steels of different classes in an aggressive NACE solution at 25°C is analyzed. The dependences of the stress leading to the transition from active corrosion to the mechanism of hydrogen embrittlement (critical stress) on the yield stress and the coefficient of stress concentration are plotted. The relationship between the critical stress, conditional yield stress, and overstress values is revealed. It is concluded that the loss of corrosion resistance for unalloyed steels with a yield stress below 500 MPa is caused by an increase in the hydrogen concentration during deformation of the material in a corrosive environment.

Проведен анализ влияния металлургических факторов на коррозионное растрескивание под напряжением сталей разного класса в агрессивном растворе NACE при 25oC. Получены зависимости напряжения перехода от активной коррозии к механизму водородного охрупчивания (критического напряжения) от величины предела текучести и коэффициента концентрации напряжений. Выявлена связь между критическим напряжением, условным пределом текучести и величиной перенапряжения. Сделан вывод о том, что потеря коррозионного сопротивления для нелегированных сталей с пределом текучести ниже 500 MPa обусловлена увеличением концентрации водорода в процессе деформации материала в коррозионной среде. Ключевые слова: коррозионное растрескивание под напряжением, водородное охрупчивание, предел текучести, коэффициент стойкости, сталь.

The analysis of data on stress corrosion cracking of different classes steels in sour H2S-CO2-Cl- solutions is carried out. The dependence of the time to failure and speed of stationary corrosion on the outside (the concentration of the solution components, temperature, the value of the tensile stress) and internal (the degree of alloying of Cr, Ni, Mo, the yield strength of steel) of the corrosion parameters is obtained The resulting expression will allow to evaluate the corrosion behavior and the possibility of using steel in an aggressive environment without long and expensive field tests.

We have analyzed the data on stress corrosion cracking of steels of various grades in acidic H2S–CO2–Cl– solutions. For the active region of corrosion, we have obtained the dependence of the lifetime and the steady-state corrosion rate on external (concentration of solution components, temperature, and tensile stress) and internal parameters of corrosion (Cr, Ni, and Mo doping level and conditional yield stress for steel). The resultant dependences will make it possible to estimate the corrosion behavior and the possibility of using steel in an aggressive environment without resorting to durable and costly natural tests.

The effects of various parameters on metabolism was analyzed in several homeothermic animals, including mammals, passerine birds, and humans. A Boltzmann equation was obtained for the basal metabolic rate, with the activation energy coinciding in magnitude with the energy of enzymatic cleavage of macroergic P–O bonds in adenosine triphosphate acid molecules. A dependence was obtained to relate the lifespan with the body temperature, body mass, basal metabolic rate, and Rubner’s constant.

Поступило в Редакцию 27 декабря 2017 г

Fragment analysis of DNA by the capillary gel-electrophoresis method is an effective tool for studying the DNA structure, which has a large number of applications (in particular, for genetic expertise of breeds and breed samples of a number of important crops). Fragment analysis of DNA is carried out in several stages. The stage of processing of the results of investigations includes the procedure of detection of peaks for standard DNA fragments. We list the features of the spectrum of the DNA fragment distribution, which necessitate the development of a new method for detecting peaks of a standard. We propose a method for their search based on comparison of the aggregate of standard lengths of DNA fragments and spectral peaks and describe the algorithm for implementing this method. We also consider in detail the critical stage of the algorithm, i.e., the choice of the threshold for the procedure of detection of peaks in the spectrum. The advantages and disadvantages of the method are enumerated and the results of testing are considered.

The influence of the dislocation mobility on the creep rate in aluminum has been estimated. In a steady state of creep, the dislocation mobility is varied by pinning dislocations using impurity atoms during heating. It has been shown that the change in the creep rate is proportional to the fraction of impurity atoms that migrate from the solid solution of deformed aluminum toward the dislocations.

Microobjects (strips) were formed by contact photolithography using Та/Ni80Fe20/Co90Fe10/Cu/Co90Fe10/Ru/Co90Fe10/Fe50Mn50/Ta spin-valves prepared by magnetron sputtering. A mutually perpendicular arrangement of uniaxial and unidirectional anisotropy axes in microobjects has been formed using two different thermomagnetic treatment regimes. The magnetoresistive sensitivity of spin valve and spin-valve-based microobject has been found to depend on the mutual arrangement of the easy magnetization axis and direction of magnetic field applied upon thermomagnetic treatment. The obtained data have been interpreted taking into account changes in the induced anisotropy and anisotropy due to the shape of the microobject.

The parameters of intergranular fracture of copper during creep under tension at T = 773 K and σ = 12.5 MPa are determined, and the contribution of grain-boundary porosity to the increase in the creep rate at stage III is estimated. The increase in the creep rate is shown to occur due to the pore-induced decrease in the grain boundary area, an increase in the mobile-dislocation density, and the deformation of the material because of the formation of pores and cracks.

The effect of uniform pressure on the activation parameters of the kinetic equation that describes the exponential dependence of the steady-state creep rate and the lifetime of polycrystalline metals on stress and temperature is estimated. It is shown that, under pressure, the parameters that determine the behavior of a metal under load are the activation energy and the internal stresses. The dependence of these parameters on the applied pressure is revealed.

A parameter is proposed to estimate the possibility of pore coalescence in deformed materials. It is shown that pore accumulation does not lead to the formation of macrocracks and subsequent fracture during uniaxial loading in the region of an exponential relation between the strain rate and the stress.