A nearby supernova (SN) explosion in the past can be confirmed by the detection of radioisotopes on Earth that were produced and ejected by the SN. We have now measured a well resolved time profile of the 60Fe concentration in a deep-sea ferromanganese crust and found a highly significant increase 2.8 Myr ago. The amount of 60Fe is compatible with the deposition of ejecta from a SN at a distanc...

Dynamic recrystallization (DRX) is almost universally observed in the microstructure of adiabatic shear bands. It is usually admitted that DRX results from the large temperatures that develop in the band along with very high local strains. This paper reports the observation of dynamically recrystallized nanograins in Ti6Al4V alloy specimens that were impact loaded to only half the failure strai...

Grain boundary segregation provides a method for stabilization of nanocrystalline metals – the selection of an alloying element that will segregate to the boundaries can lower the grain boundary energy, attenuating the driving force for grain growth. The segregation strength, relative to mixing enthalpy, of a binary system determines the propensity for segregation stabilization. This relationsh...

A constructive approach to theory of diffusion processes is proposed, which is based on application of both the symmetry analysis and method of modelling functions. An algorithm for construction of the modelling functions is suggested. This algorithm is based on the error functions expansion (ERFEX) of experimental concentration profiles. The high-accuracy analytical description of the profiles...

A family of [RE2M2L2(BA)6] (RE = Gd, Tb, Dy, Y; M = Co, Ni, Cu, Zn; L = 1,2-bis(2-hydroxy-3-methoxybenzylidene)hydrazine; BA = benzoic acid) complexes were synthesized and structurally and magnetically characterized. The magnetic interactions between spin centers were systematically investigated. The interactions of M-M (M = Co, Ni and Cu) and Gd-Ni/Cu were extracted from the fitting of the exp...

Rn×Rn S( x+ y 2 , η) e2iπ〈x−y, η〉 u(y) dy dη : such a linear operator extends as a continuous operator from S ′(Rn) to S(R) while, in the case when S ∈ S ′(Rn ×R) , one can still define Op(S) as a linear operator from S(R) to S ′(Rn) ; also, Op sets up an isometry from L(R×R) onto the space of Hilbert-Schmidt operators on L(R) . The sharp composition S1#S2 of two symbols, say lying in S(R×R) , ...

Fatigue resistance of nanocrystalline commercial pure titanium obtained by hydrostatic extrusion was investigated. Coarse grained titanium and Ti6Al4V alloy were used as the reference materials. The fatigue limit and fatigue life examined at constant stress amplitude, were found to increase significantly compared to those of the coarse-grained counterparts. It is suggested that the observed imp...