Investigation of the microstructure, mechanical properties and thermal stability of nanocomposite coatings based on amorphous carbon

The Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings based on amorphous carbon and the nanosized particles were synthesized by magnetron method. The results of the microstructure features and mechanical properties investigations of these coatings are presented. The thermal stability of microstructure and properties of these coatings at tempering up to 900°C were investigated. These coatings have a high (11–18 GPa) hardness, low (μ < 0.2) the coefficient of friction and high thermal stability of the microstructure and properties up to 700°C. The features of elastically stressed state of nanosized particles in these coatings were founded. A high local internal stresses in the TiC nanoscale particles do not observed

Thermal stability of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings

The results of the microstructure, mechanical and tribological properties investigations of Ti-C-Ni-Cr and Ti-C-Ni-Cr-Al-Si nanocomposite coatings based on amorphous carbon in the initial state and after the annealing to 900 °C are presented. The effect of annealing temperature on the microstructure, tribological and mechanical properties of Ti-C- Ni-Cr and Ti-C-Ni-Cr-Al-Si nanostructured coatings is discussed

Superconducting proximity effects in metals with a repulsive pairing interaction

Studies of the superconducting proximity effect in normal conductor/superconductor $(N/S)$ junctions almost universally assume no effective electron-electron coupling in the $N$ region. While such an approximation leads to a simple description of the proximity effect, it is unclear how it could be rigorously justified. We reveal a much more complex picture of the proximity effect in $N/S$ bilayers, where $S$ is a clean s-wave BCS superconductor and $N$ is a simple metal with a repulsive effective electron coupling. We elucidate the proximity effect behavior using a highly accurate method to self-consistently solve the Bogoliubov-deGennes equations. We present our results for a wide range of values of the interface scattering, the Fermi wave vector mismatch, the temperature, and the ratio $g$ of the effective interaction strengths in the $N$ and $S$ region. We find that the repulsive interaction, represented by a negative $g$, strongly alters the signatures of the proximity effect as can be seen in the spatial dependence of the Cooper pair amplitude and the pair potential, as well as in the local density of states near the interface.Comment: 12 pages, including 10 figures. To appear in Phys. Rev.

Numerical study of multiline CO laser frequency conversion in a ZnGeP2 crystal to the THz range

A numerical simulation was performed for frequency conversion of multiline CO laser radiation to the THz range by difference frequency generation in a ZnGeP2 crystal. It was shown that the difference frequencies spectrum can be tuned in the wavelength interval of 70–1300 μm by tuning the phase-matching angle in the range of 11° to 55°. The maximal peak power of difference frequencies radiation (integral over the spectrum) was ~0.23 W at 45° phase-matching angle, which corresponds to a peak power conversion efficiency of 6 × 10−5

Genome analysis of American minks reveals link of mutations in Ras-related protein-38 gene to Moyle brown coat phenotype

Over 35 fur colours have been described in American mink (Neovison vison), only six of which have been previously linked to specific genes. Moyle fur colour belongs to a wide group of brownish colours that are highly similar to each other, which complicates selection and breeding procedures. We performed whole genome sequencing for two American minks with Moyle (m/m) and Violet (a/a m/m /p/p) phenotypes. We identified two frame-shift mutations in the gene encoding Ras-related protein-38 (RAB38), which regulates the trafficking of tyrosinase-containing vesicles to maturing melanosomes. The results highlight the role of RAB38 in the biogenesis of melanosomes and melanin and the genetic mechanism contributing to hair colour variety and intensity. These data are also useful for tracking economically valuable fur traits in mink breeding programmes

Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1-Methylimidazolium Thiocyanate

We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Brønsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate-based protic ionic liquids for the ring-opening of donor-acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1-methylimidazolium thiocyanate under mild metal-free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three-membered ring affording pyrrolidine-2-thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time-efficient step. The ability of 1-methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)-annulation with 1-acyl-2-(2-hydroxyphenyl)cyclopropane, epoxide ring-opening and other organic transformations

Differential constraints and exact solutions of nonlinear diffusion equations

The differential constraints are applied to obtain explicit solutions of nonlinear diffusion equations. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the determining equations used in the search for classical Lie symmetries

Efficiency of different PCR-based marker systems for assessment of Iris pumila genetic diversity

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