1,571 research outputs found
An ab-initio study of the electron-phonon coupling within a Cr(001)-surface
It is experimentally well established that the Cr(001)-surface exhibits a
sharp resonance around the Fermi level. However, there is no consensus about
its physical origin. It is proposed to be either due to a single particle dz2
surface state renormalised by electron-phonon coupling or the orbital Kondo
effect involving the degenerate dxz/dyz states. In this work we examine the
electron-phonon coupling of the Cr(001)-surface by means of ab-initio
calculations in the form of density functional perturbation theory. More
precisely, the electron-phonon mass-enhancement factor of the surface layer is
investigated for the 3d states. For the majority and minority spin dz2 surface
states we find values of 0.19 and 0.16. We show that these calculated
electron-phonon mass-enhancement factors are not in agreement with the
experimental data even if we use realistic values for the temperature range and
surface Debye frequency for the fit of the experimental data. More precisely,
then experimentally an electron-phonon mass-enhancement factor of 0.70~0.10 is
obtained, which is not in agreement with our calculated values of 0.19 and
0.16. Therefore, we conclude that the experimentally observed resonance at the
Cr(001)-surface is not due to polaronic effects, but due to electron-electron
correlation effects
Nonlinear acoustic waves in channels with variable cross sections
The point symmetry group is studied for the generalized Webster-type equation
describing non-linear acoustic waves in lossy channels with variable cross
sections. It is shown that, for certain types of cross section profiles, the
admitted symmetry group is extended and the invariant solutions corresponding
to these profiles are obtained. Approximate analytic solutions to the
generalized Webster equation are derived for channels with smoothly varying
cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to
Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic
corrections introduced mainly in the Introduction and References. Several
typos were also correcte
MECHANISM OF INNOVATIVE INFRASTRUCTURE OF SUPPORT OF SMALL BUSINESS DEVELOPMENT
The relevance of the stated theme is determined by the target setting of the Russian state to build a new economy of an innovative type, where small enterprises can become drivers of innovative development. The article investigates the issues of innovation development in Russia and in particular small innovative entrepreneurship. Based on the analysis of the current situation, the problems that hinder the innovative activity of small businesses have been identified, the main of which is the unformed mechanism of innovation infrastructure to support small business. The author’s interpretation of the mechanism of innovative infrastructure of support of small business has been offered. The сreated mechanism of innovation infrastructure to support small businesses can serve as the basis of scientific and instrumental approach to the formation of strategies and programs for the development of small innovative enterprises
ТЕХНОЛОГІЧНІ АСПЕКТИ ФОРМУВАННЯ КОМУНІКАТИВНОЇ КУЛЬТУРИ ФАХІВЦІВ СОЦІАЛЬНОГО ЗАХИСТУ
The reasonability of using modern educational technologies in the process of formation of communicative culture of social protection specialists is shown. These educational technologies determine the structure and content of the teaching and learning activities of students, methods of pedagogical influence on students’ professional and personal development. They guarantee the achievement of the expected results and reflect the design of the educational process according to a certain scheme that allows solving educational problems at a high methodicallevel.Обґрунтовується доцільність використання у процесі формування комунікативної культури майбутніх фахівців соціального захисту комплексу сучасних педагогічних технологій, що визначають структуру і зміст навчально-пізнавальної діяльності студентів, способи педагогічного впливу на їхній професійний і особистісний розвиток, гарантують досягнення очікуваного результату та забезпечують високий методичний рівень вирішення педагогічних завдань
Peculiarities of the process of psychological adaptation of foreign students of Ukrainian higher education institutions of medical profile, role of emotional intelligence in the socialization process
The dynamics of increasing rates of interstate educational migration of student youth exacerbates the problems of psychological adaptation and socialization of foreign students in the context of the recipient country’s society
Strong-field approximation for Coulomb explosion of H_2^+ by short intense laser pulses
We present a simple quantum mechanical model to describe Coulomb explosion of
H by short, intense, infrared laser pulses. The model is based on the
length gauge version of the molecular strong-field approximation and is valid
for pulses shorter than 50 fs where the process of dissociation prior to
ionization is negligible. The results are compared with recent experimental
results for the proton energy spectrum [I. Ben-Itzhak et al., Phys. Rev. Lett.
95, 073002 (2005), B. D. Esry et al., Phys. Rev. Lett. 97, 013003 (2006)]. The
predictions of the model reproduce the profile of the spectrum although the
peak energy is slightly lower than the observations. For comparison, we also
present results obtained by two different tunneling models for this process.Comment: 8 pages, 4 figure
Formation of system of support of development of small youth business
The results of the research of youth entrepreneurship problems have been adduced. Institutions and programs of its support have been considered. Measures to eliminate the identified problems of attracting young people to entrepreneurship have been recommended. The formation of a new program of support «Acceleration of youth entrepreneurship» and the creation of coordination centers in the subjects of the Russian Federation «Regional youth center» have been off red. The model of the system of support of small youth entrepreneurship, which will increase entrepreneurial activity among young people and create new jobs, has been presented
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