Scanning and transmission electron microscopies are used to study the microstructure and phase composition of the surface layer of Zr–1

Scanning and transmission electron microscopies are used to study the microstructure and phase composition of the surface layer of Zr-1% Nb alloy, which was subjected to treatment by nanosecond laser pulses. During laser treatment, a thin strengthened surface layer with the fine microstructure is found to form. The strengthening of the surface layer no less than 4 mu m thick is proved to be due to the formed twin micropackets consisting of martensite nanolamellas and nano-sized omega-Zr phase.

Methods of transmission and scanning electron microscopy are used to study premartenstic states and their relation to martensitic transformations in the alloys Cu–38 wt β _2^' , β2 → β _2^” , and β2 → γ _2^' are proposed based on the crystallographic data obtained in the premartensitic state.

Abstract—It is shown that the size and shape of cementite inclusions in eutectoid steel determine its magnetic properties in both unstrained and plastically strained states. In the case of the unstrained state, the coercivity of steel comprising a fine pearlite is found to be the highest, whereas the coercivity of steel comprising a coarse pearlite is the lowest. Tensile plastic deformation leads to an increase in the coercivity of samples and a decrease in their remanence and maximum magnetic susceptibility. The appearance of bend or a second maximum in the field dependences of the magnetic susceptibility measured along the deformation direction indicates the formation of the “easy-plane” magnetic texture caused by residual compressive stresses. Calculated magnetic anisotropy fields of initial unstrained samples of eutectoid steel differing in pearlite morphology are from 10.4 to 19.1 A/cm. The plastically strained samples exhibit an increase in the induced magnetic anisotropy and, therefore, in the residual stresses as compared to those observed for the unstrained state.

Neuron activity in two symmetrical areas of the prefrontal cortex in the left and right hemispheres of the rat brain (55 and 47 neurons, respectively) was recorded as the animals performed a behavioral choice task in a two-ring maze. Experiments were performed in two sets of conditions – i) working with a conditioned signal, when excursions to the side indicated by the signal were reinforced, and ii) without a signal, when any excursion was reinforced. The levels of involvement of a neuron in different steps of the behavioral program were evaluated in terms of the level of differential activity, i.e., differences in neuron activity in right- and left-sided performances. In conditions in which the animal took the decision without orienting itself to external signals (in two behavioral situations: working without signals and erroneous performance of the program), there was a predominance of differential activity in the left hemisphere. In correct performances of the program, activity dominated in the right hemisphere. This appears to be evidence of a consistent dynamic in the interaction between the hemispheres depending on external and internal conditions and the special role of the right hemisphere in learning mechanisms and inclusion of the external determinant in the adaptive response system.

The possibility of increasing the reversible deformation to 1.9% of corrosion-resistant steels 0.30C–14Cr–15Mn–4Si–3Ni–1V and 0.30C–14Cr–15Mn–4Si–3Ni,which exhibits the shape-memory effect has been shown. The increase has been achieved at the expense of a decrease in the chromium and carbon contents in an austenite matrix, which results from the decrease in the quenching temperature and increase in the time of destabilizing carbide aging.

The behavior of rats was studied in a two-ring maze in which the animal could make its own choice of one of two trajectories of the same length, independently returning to the start point. All maze sectors – starting chamber, signal sector, arm, and feeding sector – were separated by one-way doors. The time structure of passage through the maze sectors reflected both the level of the animal’s motivation and fully defined aspects of behavior, i.e., attention, short-term memory, and long-term memory, as well as the cognitive aspect, i.e., taking movement trajectory decisions on the basis of the conditioned signal presented, and the emotional aspect, i.e., assessment of the result of the action. Analysis of the time parameters of the activity allowed changes in various behavioral components to be evaluated in relation to treatment applied to the animals and ongoing status. We suggest that this behavioral model will be useful in different types of neuropharmacological, electrophysiological, and behavioral experiments.

При снижении температуры деформации от 573 до 203-77 K в стареющем аустенитном сплаве на основе железа (Fe-35.8Ni-2.6Ti) обнаружена резкая интенсификация аномальных процессов растворения наночастиц когерентной -фазы Ni3Ti при взаимодействия с дислокациями. Это связано с подавлением (при криогенных температурах) альтернативных диффузионных процессов выделения частиц, инициируемых точечными дефектами.

Database SPBLAKES was developed, containing vast authors’ and literary geographic, morphological, climatological, limnological, and other data on 1268 natural lakes in the territory of Leningrad oblast (LO), Russian Federation. The structure, format, and the current state of the database SPBLAKES are discussed. The geographic (coordinates, elevation above sea level, and administrative position) and statistical distributions of some lacustrine dimensional (area, volume, mean and maximal depths, etc.) and dimensionless (coastline indentation, specific drainage area, etc.) morphometric and hydrochemical (water salinity, pH) characteristics are evaluated, and the distribution of lakes by bed genesis is determined. The total areas (1.291 × 103 km2) and water volumes (4.44 × 103 km3) of lakes are evaluated, and the lake area share in the total area is calculated (0.016 or 1.6%). The database SPBLAKES can be expected to help solving various theoretical and applied limnological problems.

In an aging austenitic iron-based alloy (Fe–35.8Ni–2.6Ti), when the deformation temperature decreases from 573 to 203–77 K, a sharp intensification of anomalous processes of the dissolution of nanoparticles of the coherent γ'-Ni3Ti phase has been detected upon the interaction with dislocations. This is connected with the suppression (at cryogenic temperatures) of alternative diffusion processes of the precipitation of particles initiated by point defects.

The single unit activity of the monkey parietal cortex was studied during the task of alternative spatial selection. Simultaneously activities of 6--10 neurons were recorded. It was revealed that tonic impulse activity of parietal cortex neurons forms blocks. The structure of blocks reflects the structure of behavioral task and related to the achievement of interim targets in performing of be- havioral task. Earlier the formation of similar blocks of tonic activity was shown for unit activity of putamen and prefrontal cortex. Thus the data obtained evidence in favor of that grouping of tonic activity is not an individual feature of some structures but has more general character most likely typical and for other brain areas. Generally it shows that nerve control of complex much component behavior is accomplished in segments by formation of separate blocks in neuronal activity. These blocks are related to individual groups of actions which in combination lead to a final goal--performance of behavioral task in a whole. Key words: unit activity, behavior, monkey, parietal cortex.

A nanocrystalline Fe-Ni matrix strengthened by dispersed CrN and TiN nitrides has been produced on the ion-plasma-nitrided surfaces of the austenitic Fe-Ni 38 -Cr 15 and Fe-Ni 36 -Ti 4 alloys using cyclic “nitride dissolution-nitride precipitation” phase transformations induced by megaplastic deformation. The high-pressure torsion of the nitrided alloys has led to the dissolution of the CrN nitrides and Ni 3 Ti intermetallic compounds, which appeared in the matrix, in the surface layer and to the mechanical alloying of the nitrided subsurface layer and the unnitriderd bulk of the specimens. Subsequent annealing has resulted in the formation of secondary nitrides, which propagated to a depth substantially exceeding the thickness of the original nitrided layer.

: Animal behavior is studied using a two-ring maze in which the animal has to choose one of two paths, the same length and then self-returning to the starting compartment. All sections of the labyrinth: the starting chamber, signal space, arms and food compartment blocked by one-way doors. Time periods of passing different chambers reflect different aspects of behavior: level of motivation, attention, short-term and long-term memory, cognitive (make a decision) and emotion and etc. The analysis of these time parameters allows evaluate various behavioral components, depending on the impact on the animal. We suppose that this behavior model can be useful in various neurophysiology experiments.

The reasons for occurrence of photochemical smog in the cities of the Russian Federation have been studied, as well as the contribution of different sources to air pollution by formaldehyde, nitrogen oxides, ozone and other components. It has been concluded that there is a close interrelation between the concentrations of toxic substances in the troposphere.

Carbon dioxide is a marketable product. Large quantities of the product are used for carbamide production. The designs of two installations for obtaining liquid low-temperature СO2 in the cycle of medium pressure with subsequent feeding it into the units of carbamide synthesis are considered. In the first one for СО2 condensation the use of the liquid ammonia cold has been suggested; in the second one - the cold of an absorptive ammonia-water refrigerating unit has been proposed. Liquid carbon dioxide from these installations is moved by the pump to the carbamide production unit. The specific power inputs for carbon dioxide liquefaction and feeding with the pressure level of 15 MPa in both installations were lower by 25 % than in the compressor lines used nowadays.