Belgorod State University

The paper presents a study of various structural-phase states of the Fe-Mn-5Si alloy after severe plastic deformation by equal channel angular pressing and high-pressure torsion. Various physical and mechanical characteristics of the alloy were experimentally measured and analyzed in the austenitic coarse-grained, nanostructured grain-subgrain and twinned states, as well as in the predominantly martensitic and two-phase ultrafine-grained states. Indentation methods were used to find that severe plastic deformation increases the modulus of elasticity, the work of elastic deformation, and its elastic component, reducing the contact rigidity of the indenter with the deformed material and the work of plastic deformation. In this case, the alloy in the two-phase state after deformation has the lowest modulus of elasticity and work of plastic deformation at the highest work of elastic deformation.

High-entropy topological insulator (Bi3/4Sb1/4)(2)(Te2/5Se2/5S1/5)(3) has been for the first time prepared by self-propagating high-temperature synthesis and melting methods. Single-crystalline thick-filmed sample with thickness of similar to 0.1 mm was applied to examine the photoresponse properties by using room-temperature chopped-light technique. Photodetector based on (Bi3/4Sb1/4)(2)(Te2/5Se2/5S1/5)(3) demonstrated strong photovoltaic response under irradiation of a white LED light, covering 420-730 nm range. The photocurrent increases from similar to 20 to similar to 55 mu A with the increase in intensity from 100 to 600 W/m(2) that is originated from the increase in the number of non-equilibrium carriers generated by light. Room-temperature responsivity and detectivity of the photodetector are similar to 8.7 mA/W and similar to 10(9) Jones, respectively.

CaSO4-based citrogypsum was used to prepare bulk samples of calcium sulfate hemihydrate (CaSO40.5H(2)O). To alter composition and improve conductivity, the samples were treated at 95 degrees C in 85 wt% orthophosphoric acid for 1 to 15 min. Within <1 min, CaSO40.5H(2)O transforms into CaSO42H(2)O. At longer times, partial dehydration converts part of the CaSO42H(2)O. back into CaSO40.5H(2)O, yielding a two-phase mixture. Acid treatment induces cation (2H(+) <-> Ca2+) and anion ((HPO4)(2-) <-> (SO4)(2-)) exchange, producing a transition from insulating to solid-electrolyte behavior. Weakly bound H+ ions, incorporated either by Ca2+ substitution or via (HPO4)(2-) residues, act as mobile charge carriers and enable proton conductivity. Residues that release protons convert to (PO4)(3-) groups, which can be displaced in an alternating field, generating ionic polarization and relaxation currents. The combined effects of H+ mobility and (PO4)(3-) polarization produce two arcs in AC impedance spectra. Conductivity parameters extracted with the Cole model strongly depend on sample composition.

This work presents a comprehensive methodology for synthesizing chemically pure two-dimensional molybdenum boride (MoB MBene) with a controlled morphology. The precursor MoAlB MAB phase was successfully synthesized via a molten-salt-assisted solid-state reaction, as confirmed by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. An optimized two-step chemical etching protocol, involving treatment with hydrofluoric acid followed by boiling in a sodium hydroxide solution, effectively removed the aluminum layers and accompanying impurities (AlF3, Na2Al22O34), yielding a chemically pure MoB powder. For the effective exfoliation of multilayer MoB into nanosheets, a two-step mechanical procedure was employed, comprising of preliminary ball milling in isopropyl alcohol to weaken the interlayer bonds and subsequent ultrasonication. The resulting exfoliated MoB MBene nanosheets exhibit an average lateral size of similar to 60 nm and an average thickness of similar to 4 nm, corresponding to a few atomic layers. The phase composition and high crystallinity of the exfoliated particles were confirmed by XRD and selected area electron diffraction (SAED) methods. The high yield of exfoliated particles (80-85 %) demonstrates the effectiveness of the developed methodology.

Invasive plant species present a growing ecological and economic challenge, and often adapt rapidly to their novel environments through complex demographic and evolutionary processes. Invasion genomics offers powerful tools to disentangle these processes, but most studies rely on geographically narrow sampling across native and non-native ranges. Erigeron canadensis is a cosmopolitan weed native to North America that has successfully invaded diverse climates worldwide. We used double-digest restriction site-associated DNA sequencing (ddRADseq) to investigate the genetic diversity and structure of 280 E. canadensis populations across the Northern Hemisphere. We found that native and non-native populations maintained comparable genetic diversity. Population structure analyses revealed four genetic clusters that were mainly differentiated along latitudinal and aridity gradients. However, one cluster was strongly overrepresented in the non-native compared to the native range. In the native range, genetic differentiation was shaped by spatial and environmental gradients, while in non-native regions human-mediated dispersal and repeated introductions disrupted environmentally driven genetic structure. Migration network analyses revealed limited intercontinental connectivity and a possible role of long-distance dispersal in within-range expansions. Genomic offset analyses showed that genotype-environment mismatches in non-native populations associated with reduced growth and reproduction. Together, our results indicate that the invasion dynamics of E. canadensis were driven by multiple introductions, population admixture, and lineage sorting, while some genotypes contributed disproportionately to the spread of this invader. The presence of apparent maladaptation suggests that even long-established invaders may still be evolving in response to their novel environment, raising concerns about potential future expansions.