The phase composition, morphology and compressibility of graphene-zirconia composite nanostructured powder

Nanostructured composite particles of nano- and submicron sizes were synthesized by a combination of sol-gel and sonochemical techniques. Their graphene content was 0.8-0.9 wt%. These layered particles consisted of graphene sheets in which zirconia nanocrystals were discretely incorporated. The synthesized powders were characterized using XRD, TEM, HRTEM, diffusion aerosol spectrometry and elemental analysis. A comparison of the compressibility modulus, limit values of linear section deformation and compressibility factor shows that the compressibility of the composite is difficult to achieve compared to that of pure zirconia, apparently, due to the low elasticity of graphene sheets.

Formation of Boron-Carbon Nanosheets and Bilayers in Boron-Doped Diamond: Origin of Metallicity and Superconductivity

The insufficient data on a structure of the boron-doped diamond (BDD) has frustrated efforts to fully understand the fascinating electronic properties of this material and how they evolve with doping. We have employed X-ray diffraction and Raman scattering for detailed study of the large-sized BDD single crystals. We demonstrate a formation of boron-carbon (B-C) nanosheets and bilayers in BDD with increasing boron concentration. An incorporation of two boron atoms in the diamond unit cell plays a key role for the B-C nanosheets and bilayer formation. Evidence for these B-C bilayers which are parallel to {111} planes is provided by the observation of high-order, super-lattice reflections in X-ray diffraction and Laue patterns. B-C nanosheets and bilayers minimize the strain energy and affect the electronic structure of BDD. A new shallow acceptor level associated with B-C nanosheets at ~37 meV and the spin-orbit splitting of the valence band of ~6 meV are observed in electronic Raman scattering. We identified that the superconducting transitions occur in the (111) BDD surfaces only. We believe that the origin of Mott and superconducting transitions is associated with the two-dimensional (2D) misfit layer structure of BDD. A model for the BDD crystal structure, based on X-ray and Raman data, is proposed and confirmed by density functional theoretical calculation.

[The characterization of bean yellow mosaic virus isolated from soybean]

The comparative characteristics of biological, physico-chemical and antigenic properties of bean yellow mosaic virus isolated from soybeans are shown. The obtained results indicate the existence of individual properties of the isolate which help to distinguish it from the typical strains and isolates studied previously in Ukraine by other authors.