Self-energy embedding theory (SEET) for periodic systems

We present an implementation of the self-energy embedding theory (SEET) for periodic systems and provide a fully self-consistent embedding solution for a simple realistic periodic problem - 1D crystalline hydrogen - that displays many of the features present in complex real materials. For this system, we observe a remarkable agreement between our finite temperature periodic implementation results and well established and accurate zero temperature auxiliary quantum Monte Carlo data extrapolated to thermodynamic limit. We discuss differences and similarities with other Green's function embedding methods and provide the detailed algorithmic steps crucial for highly accurate and reproducible results

Renormalized spectral function for Co adatom on the Pt(111) surface

The strong Coulomb correlations effects in the electronic structure of magnetic Co adatom on the Pt(111) surface have been investigated. Using a realistic five d-orbital impurity Anderson model at low temperatures with parameters determined from first-principles calculations we found a striking change of the electronic structure in comparison with the LDA results. The spectral function calculated with full rotationally invariant Coulomb interaction is in good agreement with the quasiparticle region of the STM conductance spectrum. Using the calculated spin-spin correlation functions we have analyzed the formation of the magnetic moments of the Co impurity orbitals.Comment: 4 pages, 4 figure

The development of teachers’ media competence

The article discusses one of the most promising trends in modern education - media education. The authors defined with sufficient clarity the nature of concepts: media competence, media competence of teachers allocated its components and their for-mation system is constructed based on media competence. The author describes the method of formation of media competence of teachers, consisting of preparatory, theoretical and practical steps and discusses some results of an experimental study within the framework of the developed systemyesBelgorod State Universit

Role of three-particle vertex within dual fermion calculations

We investigate the influence of self-energy diagrams beyond the two-particle vertex level within dual fermion theory. Specifically, we calculate the local three-particle vertex and construct from it selected dual fermion self-energy corrections to dynamical mean field theory. For the two-dimensional Hubbard model, the thus obtained self-energy corrections are small in the parameter space where dual fermion corrections based on the two-particle vertex only are small. However, in other parts of the parameter space, they are of a similar magnitude and qualitatively different from standard dual fermion theory. The high-frequency behaviour of the self-energy correction is - surprisingly - even dominated by corrections stemming from the three-particle vertex

INVESTIGATIONS OF THE INFLUENCE OF THE TECHNOLOGICAL MODES OF MANUFACTURE OF PENOKERAMIC INSULATION PANELS IN THE MICROWAVE FIELD

 In modern technologies, high frequency (HF) and ultrahigh frequency (UHF) currents are widely used for heating and drying various materials in many industries [1, 2]. However, this method has not been used to form cellular structures. The presence of a simple method of obtaining a porous structure, by bringing solutions to boiling excess moisture in the fields of HD and microwave, will make it possible to improve industrial production, reduce electricity consumption, and reduce the cost of components, etc. [2, 3].Keywords: foam ceramics, diatomite, termal insulation, microsilica, sol-gel method.1Жугинисов М. Т., 2Селяев В. П., 1,3Нурлыбаев Р. Е., 1Орынбеков Е. С., 1Джолдасов А. А., 3Якупбаев С. А., 3Искаков А. А., 1Мурзагулова А. А. Исследования влияния  технологических режимов изготовления пенокерамических изоляционных панелей в свч – поле/ 1 «Казахский национальный исследовательский технический университет имени К.И. Сатпаева», г. Алматы, Республика Казахстан, 2«Национальный исследовательский Мордовский государственный университет им. Н.П. Огарева», г. Саранск, Россия, 3Товарищество с ограниченной ответственностью «SAVENERGY»,В современных технологиях широко используют токи высокой частоты (ТВЧ) и сверхвысокой частоты (СВЧ) для нагрева и сушки различных материалов во многих отраслях промышленности [1, 2]. Однако для формирования ячеистых структур этот метод до настоящего времени не применялся. Наличие простого метода получения пористой структуры, путем доведения растворов до выкипания избыточного количества влаги в полях ТВЧ и СВЧ даст возможность улучшить индустриальность производства, сократить расход электроэнергии, удешевить компоненты  т. д [2, 3]. Ключевые слова: пенокерамика, диатомит, теплоизоляция, микрокремнезем, золь-гель метод

ARC‐1, a sequence element complementary to an internal 18S rRNA segment, enhances translation efficiency in plants when present in the leader or intercistronic region of mRNAs

The sequences of different plant viral leaders with known translation enhancer ability show partial complementarity to the central region of 18S rRNA. Such complementarity might serve as a means to attract 40S ribosomal subunits and explain in part the translation‐enhancing property of these sequences. To verify this notion, we designed β‐glucuronidase (GUS) mRNAs differing only in the nature of 10 nt inserts in the center of their 41 base leaders. These were complementary to consecutive domains of plant 18S rRNA. Sucrose gradient analysis revealed that leaders with inserts complementary to regions 1105-1114 and 1115-1124 (‘ARC‐1') of plant 18S rRNA bound most efficiently to the 40S ribosomal subunit after dissociation from 80S ribosomes under conditions of high ionic strength, a treatment known to remove translation initiation factors. Using wheat germ cell‐free extracts, we could demonstrate that mRNAs with these leaders were translated more than three times more efficiently than a control lacking such a complementarity. Three linked copies of the insert enhanced translation of reporter mRNA to levels comparable with those directed by the natural translation enhancing leaders of tobacco mosaic virus and potato virus Y RNAs. Moreover, inserting the same leaders as intercistronic sequences in dicistronic mRNAs substantially increased translation of the second cistron, thereby revealing internal ribosome entry site activity. Thus, for plant systems, the complementary interaction between mRNA leader and the central region of 18S rRNA allows cap‐independent binding of mRNA to the 43S pre‐initiation complex without assistance of translation initiation factor

Applications of a finite-volume algorithm for incompressible MHD problems

We present the theory, algorithms and implementation of a parallel finite-volume algorithm for the solution of the incompressible magnetohydrodynamic (MHD) equations using unstructured grids that are applicable for a wide variety of geometries. Our method implements a mixed Adams-Bashforth/Crank-Nicolson scheme for the nonlinear terms in the MHD equations and we prove that it is stable independent of the time step. To ensure that the solenoidal condition is met for the magnetic field, we use a method whereby a pseudo-pressure is introduced into the induction equation; since we are concerned with incompressible flows, the resulting Poisson equation for the pseudo-pressure is solved alongside the equivalent Poisson problem for the velocity field. We validate our code in a variety of geometries including periodic boxes, spheres, spherical shells, spheroids and ellipsoids; for the finite geometries we implement the so-called ferromagnetic or pseudo-vacuum boundary conditions appropriate for a surrounding medium with infinite magnetic permeability. This implies that the magnetic field must be purely perpendicular to the boundary. We present a number of comparisons against previous results and against analytical solutions, which verify the code's accuracy. This documents the code's reliability as a prelude to its use in more difficult problems. We finally present a new simple drifting solution for thermal convection in a spherical shell that successfully sustains a magnetic field of simple geometry. By dint of its rapid stabilization from the given initial conditions, we deem it suitable as a benchmark against which other self-consistent dynamo codes can be tested

Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh