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Experimental procedures are described for determining the dynamic strength properties of high-strength hard alloys. Results are provided for dynamic tests in compression, bending, and spailing. Failure of cylindrical strikers is studied in the case of collision with a target.

Dynamic tensile tests of materials were numerically modeled by the finite element method. In the calculations the elastoviscoplastic model of material was used, and the connectedness of thermal and deformation processes was taken into account. The limits of applicability of the test method under consideration were determined. The article also analyzes the methods of evaluating the strain rate for different levels of deformation in the range of loading rates 10–200 m/sec.

Conclusions 1.The mechanism that controls plastic deformation varies with decreasing stress level on the front of the elastic precursor during the propagation of an elastoplastic wave: collective shear near the contact surface, the mechanism of viscous dislocation damping as the elastic precursor decays, and the thermal-fluctuation mechanism as one moves away from the surface. This entire process is described by equation of state (3), and on individual segments, precursor decay may be satisfactorily described by equations with a more limited number of constants.2.The decay of the elastic precursor of a plane wave in steel 20, which can be predicted on the basis of the dislocation model of plastic flow (3), the parameters of which are determined from experimental data on static and dynamic tensioning, is in satisfactory agreement with experimental results.3.The Huygens dynamic limit, which is determined from the amplitude of the elastic precursor in the region of the latter's weak decay, corresponds to the static yield point eyx only for materials that are slightly sensitive to strain rate in the region en ? 103 sec-1; in the opposite case, it is 1.5–2 times higher than syx at a distance of 20–40 mm from the surface being loaded.4.The viscosity µt of the material, as determined from the decay of the elastic precursor near the loaded surface of a specimen, is an average value, the accuracy of which depends on the wave intensity s0 and the region of elastic-precursor propagation under consideration (0...x), and characterizes the average value of the material's viscosity at high strain rates en sec-1).

Two protein-coding regions (cytochrome b, ATPase 8, and part of ATPase 6) from mitochondrial DNA of Cottus kessleri, Cottocomephorus grewingki, and Cottocomephorus inermis-Baikalian endemic sculpins—were amplified via polymerase chain reaction, and sequenced. Two novel primers-L8352 (5'-TAAAGATTGGTGAC TCCCAACCACC) and H8773 (5'-GTAGGGAGT AAGCCCAATATGTT)-were used for the latter region. Phylogenies suggested by sequence divergence of the genes of ATPases appeared to be different from those computed from data for cytochrome b. The time of species branching was estimated as 1–2 million years (Myr) on the basis of merged sequences. Hence, members of the Baikalian cottoid species flock are much more distant from each other than members of the cichlid fish flocks of the great lakes of Africa (0.2 Myr). Topology of the phylogenetic tree does not contradict the relationships derived from morphological data. However, genetic distances suggest that C. grewingki and C. inermis are not sister species, contrary to general belief.