Low-energy quasiparticle states at superconductor-CDW interfaces

Quasiparticle bound states are found theoretically on transparent interfaces of d-wave superconductors (dSC) with charge density wave solids (CDW), as well as s-wave superconductors (sSC) with d-density waves (DDW). These bound states represent a combined effect of Andreev reflection from the superconducting side and an unconventional quasiparticle Q-reflection from the density wave solid. If the order parameter for a density wave state is much less than the Fermi energy, bound states with almost zero energy take place for an arbitrary orientation of symmetric interfaces. For larger values of the order parameter, dispersionless zero-energy states are found only on (110) interfaces. Two dispersive energy branches of subgap quasiparticle states are obtained for (100) symmetric interfaces. Andreev low-energy bound states, taking place in junctions with CDW or DDW interlayers, result in anomalous junction properties, in particular, the low-temperature behavior of the Josephson critical current.Comment: 6 pages, 2 figure

HRTEM observation of the monoclinic-to-tetragonal (m-t) phase transition in nanocrystalline ZrO₂

The orientation relations m(100) || t(001), m[001] || t[110]; m(011) || t(100), m[001] || t[110]; m(100) || t(110), m[001] || t[001]; m(013) || t(116), m[001] || t[001]; (indices for the primitive tetragonal cell) have been found between the tetragonal (t) and monoclinic (m) domains during the electron irradiation-induced m-t phase transition observed in-situ with HREM within isolated zirconia nanoparticles. Geometric models of the m-t interfaces are proposed. Keywords High-resolution transmission electron microscopy, nanoparticles, orientation relations, polymorphism, zirconia, catalys

The Financial Component of the Scientific Publication’s Value Original article

Publication activity in modern society is presented as a driving force of scientific and technological development and as an indicator of university management reporting. The article is devoted to the study of approaches to determining the monetary value of a scientific publication, taking into account different behavior’s motives of researchers and teachers in higher education as authors. The methodological basis of the study was formed by concepts of creating a public good and financial good, concepts of scientific productivity and academic remuneration, neoclassical and neoinstitutional economic theories, approaches to the implementation of state policy in the field of science and education in terms of stimulating scientific publications. Research methods: critical and comparative analysis, with the inclusion of three groups of methods: a) the study of direct and indirect authors’ motives and traps in the publication of scientific papers; b) asset evaluation methods; c) a combination of socio-economic campaigns for monetary evaluation of the results of scientific research. Asset valuation approaches have been adapted to assess the scientific publication’s value from the position of the author as a beneficiary. The theoretical and practical significance of the research lies in the contribution to the value dimension of scientific publications for their authors in the conditions of academic capitalism with potential opportunities to receive monetary income from the results of their research

Coherent transport in homojunction between excitonic insulator and semimetal

From the solution of a two-band model, we predict that the thermal and electrical transport across the junction of a semimetal and an excitonic insulator will exhibit high resistance behavior and low entropy production at low temperatures, distinct from a junction of a semimetal and a normal semiconductor. This phenomenon, ascribed to the dissipationless exciton flow which dominates over the charge transport, is based on the much longer length scale of the change of the effective interface potential for electron scattering due to the coherence of the condensate than in the normal state.Comment: RevTeX 4.0, 13 pages, 5 b/w figures, 1 colour figure, 1 table. Version modified with respect to the original, which will appear in Physical Review Letters. This version includes the supplementary (EPAPS) material as an Appendix, and it is slightly longer than the accepted version (more text and references

Changes in the mountain river discharge in the northern Tien Shan since the mid-20th Century: Results from the analysis of a homogeneous daily streamflow data set from seven catchments

This study is an assessment of the changes in seasonal and monthly flow in seven catchments draining the northern Tien Shan Mountains in Central Asia over a period from the 1950s to the present day. The purpose is to provide a first assessment of the flow response to climate change in regionally important catchments given their contribution to the water resource. All the catchments have a natural flow regime, and are therefore sensitive to climate change, but differ in area, elevation and glacial extent. Trends in flow were characterised using the Mann-Kendall test for standard meteorological seasons and individual months for mean flow, five flow quantiles and peak-over-threshold series for the period 1974–2013 at all sites and from the 1950s where data were available. The results were related to trends in seasonal temperature and precipitation from the regional high elevation meteorological stations and glacier mass balance, equilibrium line altitude (ELA) and accumulation area ratio (AAR) records from the Tuyuksu glacier. The results show no reduction in streamflow in any catchment or season in the northern Tien Shan since the 1950s. Positive trends in all flow indicators, including peak over- threshold frequency, were observed in catchments with higher glacierization of over 10% and extensive presence of rock glaciers and permafrost indicating increased melt over the period which is characterised by a long-term increase in temperature. These trends were most evident in autumn and winter. In catchments with low glacierization, variability in summer flow was controlled primarily by precipitation of the preceding cold season. Correlation with glacier mass balance was weak but changes in ELA and AAR indicate that production of liquid runoff at higher elevations contributes to increased streamflow partly compensating for the declining glacier area. The observed changes in streamflow do not suggest any immediate problems with water availability in the northern Tien Shan. On the contrary, increased autumn and winter flows point at a more prolonged recharge of reservoirs and aquifers though eventually this water source will be exhausted

Heterogeneous Catalysis under pressure - In-situ neutron diffraction under industrial conditions

The present work describes the application of a tubular reactor that allows in-situ neutron diffraction on working catalysts at high pressures. The designed reactor enables the application to a sample of industrially-relevant reaction conditions, i.e., in a temperature range up to 330° C and 60 bar pressure, coupled with online gas-analysis. Application of the cell is demonstrated by ammonia synthesis over a commercial catalyst with diffraction data obtained from the high-resolution powder diffractometer, Echidna, at the Australian Nuclear Science and Technology Organisation, ANSTO

Comparative study of hydrotalcite-derived supported Pd₂Ga and PdZn intermetallic nanoparticles as methanol synthesis and methanol steam reforming catalysts

An effective and versatile synthetic approach to produce well-dispersed supported intermetallic nanoparticles is presented that allows a comparative study of the catalytic properties of different intermetallic phases while minimizing the influence of differences in preparation history. Supported PdZn, Pd2Ga, and Pd catalysts were synthesized by reductive decomposition of ternary Hydrotalcite-like compounds obtained by co-precipitation from aqueous solutions. The precursors and resulting catalysts were characterized by HRTEM, XRD, XAS, and CO-IR spectroscopy. The Pd2+ cations were found to be at least partially incorporated into the cationic slabs of the precursor. Full incorporation was confirmed for the PdZnAl-Hydrotalcite-like precursor. After reduction of Ga- and Zn-containing precursors, the intermetallic compounds Pd2Ga and PdZn were present in the form of nanoparticles with an average diameter of 6 nm or less. Tests of catalytic performance in methanol steam reforming and methanol synthesis from CO2 have shown that the presence of Zn and Ga improves the selectivity to CO2 and methanol, respectively. The catalysts containing intermetallic compounds were 100 and 200 times, respectively, more active for methanol synthesis than the monometallic Pd catalyst. The beneficial effect of Ga in the active phase was found to be more pronounced in methanol synthesis compared with steam reforming of methanol, which is likely related to insufficient stability of the reduced Ga species in the more oxidizing feed of the latter reaction. Although the intermetallic catalysts were in general less active than a Cu-/ZnO-based material prepared by a similar procedure, the marked changes in Pd reactivity upon formation of intermetallic compounds and to study the tunability of Pd-based catalysts for different reactions

Current Problems of the Tertiary Education Modernization and Reform Practices

The sphere of postgraduate studies is the most governance reform-sensitive element of high school educational system in Russia.The article focuses on the governmental decisions taken to address difficulties in high school modernization sphere. The article posits that the mainstream modernization vector of educational system connected with the upgraded scientific and pedagogical personnel education is performed in accordance with transformational process set forth in Bologna declaration signed by the Russian Federation. The Covid-19 pandemic challenged the postgraduate reform results in Russia. The article provides a thorough and discourse analysis of scientific publications, expert interviews and normative documents. The study concludes that the set of fundamental approaches to further Russian system of postgraduate studies is currently semi-functional.Current reforms seek to overcome a destructive impact of the current postgraduate studies system