Features of the Defect Structure of LiNbO:Mg:B Crystals of Different Composition and Genesis.

We proposed and investigated a refinement of technology for obtaining Mg-doped LiNbO (LN) crystals by co-doping it with B. LN:Mg (5.0 mol%) is now the most widely used material based on bulk lithium niobate.

Asymmetric Synthesis of Functionalized α-Amino Acid Derivatives via the γ-Pyrone Carbaldimine-Based Organocatalytic Mannich Reaction.

A powerful synthetic strategy for the asymmetric synthesis of enantiomerically enriched γ-functionalized α-amino acid derivatives based on the highly stereoselective proline-catalyzed Mannich-type reaction of pre-prepared or -generated γ-pyrone-derived aldimines with carbonyl compounds and subsequent transformations of multifunctional reaction products has been developed. A significant positive nonlinear effect was detected for the key organocatalytic reaction. The developed strategy was applied for facile gram-scale preparation of ()-γ-oxonorvaline, used for site-specific modification of proteins, and both enantiomers of amycolatolide A recently isolated from the lichen-derived actinomycete sp.

A new remarkable species of Xyletinus Latreille, 1809 (Coleoptera: Ptinidae: Xyletininae) from southern Kazakhstan.

Xyletinus (Xeronthobius) diaphanus sp. n. from southern Kazakhstan is described, illustrated, and compared with the known members of the subgenus.

Features of the Defect Structure and Luminescence of Nominally Pure Lithium Niobate Crystals Produced Using Different Technologies.

We have established that luminescence in lithium niobate crystals both congruent and near-stoichiometric (R ≈ 1) is due to point defects in the cationic sublattice and intraconfigurational transitions in the oxygen-octahedral NbO clusters. We have also determined that the main contribution to the luminescence in the visible and near IR regions is made by luminescence centers with the participation of Nb defects: the Nb-Nb bipolaron pair and the Nb-O defect in a congruent crystal. The minimum intensity of bipolaron luminescence has been observed in stoichiometric crystals obtained using different technologies.

Magnetotelluric data analysis using 2D inversion: A case study from Al-Mubazzarah Geothermal Area (AMGA), Al-Ain, United Arab Emirates.

Geothermal manifestations (hot springs) emerge in the Al-Mubazzarah Geothermal Area (AMGA), Al-Ain city, Abu Dhabi Emirate, United Arab Emirates. This paper presents the application and results of a Magnetotelluric (MT) survey, which was carried out in 2017 at the AMGA geothermal field. The MT method was used to investigate the variations in the electrical conductivity beneath the AMGA.