120 research outputs found
Structure stability in the simple element sodium under pressure
The simple alkali metal Na, that crystallizes in a body-centred cubic
structure at ambient pressure, exhibits a wealth of complex phases at extreme
conditions as found by experimental studies. The analysis of the mechanism of
stabilization of some of these phases, namely, the low-temperature Sm-type
phase and the high-pressure cI16 and oP8 phases, shows that they satisfy the
criteria for the Hume-Rothery mechanism. These phases appear to be stabilized
due to a formation of numerous planes in a Brillouin-Jones zone in the vicinity
of the Fermi sphere of Na, which leads to the reduction of the overall
electronic energy. For the oP8 phase, this mechanism seems to be working if one
assumes that Na becomes divalent metal at this density. The oP8 phase of Na is
analysed in comparison with the MnP-type oP8 phases known in binary compounds,
as well as in relation to the hP4 structure of the NiAs-type
The Representation of the Image of Russia in Foreign National Mass Media Discourse
This article focuses on the representation of the image of Russia in the discourse of foreign media (2014–2020). Taking into account the definition of the image of the state as a special concept, the article claims the lexeme «Russia», as well as the identities associated with this image in political and mass-information discourse. This concept contains historical, metaphorical, evaluative, ethnocultural and associative layers. Based on scientific research on the problems of media discourse, image-formation, associations, and using the methods of critical discourse and conceptual metaphorical analysis, the article reveals the range of means of reaching the concept of «Russia» used by the media. Discourse depends on grammar, semiotics, semantics, structure and argumentation, therefore it is important to answer the questions: how do «they» speak about «us» and how is the image of «us» formed in text or speech? To achieve the goal, we had content analysis of massmedia and had the associative experimental technique too. These tools demonstrate the ideological values of the discourse in question and the associations that it forms in the minds of people. The paper suggests that the scheme of analysis of the image of state in the political mass media discourse, offered in it, can be applied to the investigation of images of other states
Simple Metals at High Pressure
In this lecture we review high-pressure phase transition sequences exhibited
by simple elements, looking at the examples of the main group I, II, IV, V, and
VI elements. General trends are established by analyzing the changes in
coordination number on compression. Experimentally found phase transitions and
crystal structures are discussed with a brief description of the present
theoretical picture.Comment: 22 pages, 4 figures, lecture notes for the lecture given at the Erice
course on High-Pressure Crystallography in June 2009, Sicily, Ital
Approaches to the construction of simulation model of the process optimization of rare plants microclonal propagation
The authors present approaches to constructing an imitation model for the optimization of the process of rare plants microclonal reproduction (on the example of the Belgorod region), which allow to identify the most effective ways of explants sterilization, to define the optimal composition of nutrient media for regenerants growth (tube plants) and growth regulators (phytohormones) for propagation of mini-plant
Breeding of Vicia faba L. in relation to drought resistance
The Yu.N. Kurkina field method was used to determine the drought tolerance of bean plants. An analysis of the totality of ecological and morphological traits of forage bean varieties of different origins revealed varieties with pronounced xeromorphicity with low plant heights and narrow leaves. The varieties with high drought resistance have been identifie
Evidence of local superconductivity in granular Bi nanowires fabricated by electrodeposition
An unusual enhancement of resistance (i.e., superresistivity) below a certain
characteristic temperature Tsr was observed in granular Bi nanowires. This
superresistive state was found to be dependent on the applied magnetic field
(H) as well as the excitation current (I). The suppression of Tsr by magnetic
field resembles that of a superconductor. The observed superresistivity appears
to be related to the nucleation of local superconductivity inside the granular
nanowire without long-range phase coherence. The phenomenon is reminiscent of
the Bose-insulator observed previously in ultra thin two-dimensional (2D)
superconducting films and 3D percolative superconducting films.Comment: 11 pages, 5 figures. submitted to PR
Effect of pressure on the Raman modes of antimony
The effect of pressure on the zone-center optical phonon modes of antimony in
the A7 structure has been investigated by Raman spectroscopy. The A_g and E_g
frequencies exhibit a pronounced softening with increasing pressure, the effect
being related to a gradual suppression of the Peierls-like distortion of the A7
phase relative to a cubic primitive lattice. Also, both Raman modes broaden
significantly under pressure. Spectra taken at low temperature indicate that
the broadening is at least partly caused by phonon-phonon interactions. We also
report results of ab initio frozen-phonon calculations of the A_g and E_g mode
frequencies. Presence of strong anharmonicity is clearly apparent in calculated
total energy versus atom displacement relations. Pronounced nonlinearities in
the force versus displacement relations are observed. Structural instabilities
of the Sb-A7 phase are briefly addressed in the Appendix.Comment: 10 pages, 8 figure
DETECTION OF TUBERCULOUS MYCOBACTERIA IN THE BLOOD OF PATIENTS WHEN SUSPECTING TUBERCULOUS SEPSIS
The increase in HIV patients manifesting clinical signs of sepsis requires up-to-date, rapid and reliable techniques for etiologic diagnostics.The analysis has included 53 publications related to various aspects of tuberculous bacteriemia, resources for its detection and their efficiency. According to the publications tuberculous mycobacteria in blood can be detected in HIV-positive patients with severe immune suppression (CD4: 17-18 cells/mcl) and presence of the following clinical and laboratory and X-ray signs: fever, severe anemia, paratracheal lymphoadenopathy, miliary dissemination. It is feasible to test the blood in order to detect tuberculous mycobacteria only in the very ill HIV positive patients in whom tuberculosis is suspected and it is impossible to collect sputum and there are no obvious signs of pulmonary lesions.The presence oftuberculous mycobacteria in blood isrelated to the high mortality level (up to 60%) and the immediate prescription of anti-tuberculosis therapy can reduce it. Antiretroviral therapy can reduce the chances of tuberculous sepsis development. Development and optimization of test systems for rapid detection of DNA of tuberculous mycobacteria in blood can be fairly promising for the diagnostics of the urgent tuberculosis
Digital therapeutics as an innovative area of logopedic work
В статье рассматривается перспективное направление цифровой терапии в восстановлении речи у пациентов с афазией.The article deals with the promising area of digital therapeutics for rehabilitation of the speech function in patients with aphasia
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