A new electromagnetic mode in graphene

A new, weakly damped, {\em transverse} electromagnetic mode is predicted in graphene. The mode frequency $\omega$ lies in the window $1.667<\hbar\omega/\mu<2$, where $\mu$ is the chemical potential, and can be tuned from radiowaves to the infrared by changing the density of charge carriers through a gate voltage.Comment: 5 pages, 4 figure

Threshold photoelectron photoion coincidence spectroscopy and selected ion flow tube reactions of CHF3: comparison of product branching ratios

The threshold photoelectron and threshold photoelectron photoion coincidence spectra of CHF$_3$ in the range 13.5 – 24.5 eV have been recorded. Ion yields and branching ratios have been determined for the three fragments CF$_3^+$, CHF2$^+$ and CF$^+$. The mean kinetic energy releases into fragment ions involving either C-H or C-F bond cleavage have been measured, and compared with statistical and impulsive models. CHF$_3^+$ behaves in a non-statistical manner characteristic of the small-molecule limit, with the ground electronic state and low-lying excited states of CHF$_3^+$ being largely repulsive along the C-H and C-F coordinates, respectively. The rate coefficients and product ion branching ratios have been measured at 298 K in a selected ion flow tube for the reactions of CHF$_3$ with a large number of gas-phase cations whose recombination energies span the range 6.3 through 21.6 eV. A comparison between the branching ratios from the two experiments, together with an analysis of the threshold photoelectron spectrum of CHF$_3$, shows that long-range charge transfer probably occurs for the Ar$^+$ and F$^+$ atomic ions whose recombination energies lie above ca. 15 eV. Below this energy, the mechanism involves a combination of short-range charge transfer and chemical reactions involving a transition state intermediate

Representations of sl(2,?) in category O and master symmetries

We show that the indecomposable sl(2,?)-modules in the Bernstein-Gelfand-Gelfand category O naturally arise for homogeneous integrable nonlinear evolution systems. We then develop a new approach called the O scheme to construct master symmetries for such integrable systems. This method naturally allows computing the hierarchy of time-dependent symmetries. We finally illustrate the method using both classical and new examples. We compare our approach to the known existing methods used to construct master symmetries. For new integrable equations such as a Benjamin-Ono-type equation, a new integrable Davey-Stewartson-type equation, and two different versions of (2+1)-dimensional generalized Volterra chains, we generate their conserved densities using their master symmetries

Numerical realization of spatial model of system building-base-ground

For example, a typical brick building is considered in the process of modeling and calculation of loaded deformed condition of the space system building-base-ground. The numerical implementation of the nonlinear problem in view of the structural destruction of materials by finite element method is in accordance with the developed algorithm. Crack propagation is presented in pattern and contour plots of stress and displacement, resulting from the calculation

Diacoptical analysis algorithms of topological site models of information backup and storage carrier

Diacoptical topological models of algorithms analysis describes the tape transportation mechanism with the account of the distribution of options of tape and fast algorithms for obtaining the characteristic polynomial of the transfer function of the system and for graphs of finite element model of the tape for two-node cubic and rod finite elements

Properties and Structural Transformations of Mgb2-tapes under the Action of Plasma Shock Waves

The current-carrying properties (

A multiloop improvement of non-singlet QCD evolution equations

An approach is elaborated for calculation of "all loop" contributions to the non-singlet evolution kernels from the diagrams with renormalon chain insertions. Closed expressions are obtained for sums of contributions to kernels $P(z)$ for the DGLAP equation and $V(x,y)$ for the "nonforward" ER-BL equation from these diagrams that dominate for a large value of $b_0$, the first $\beta$-function coefficient. Calculations are performed in the covariant $\xi$-gauge in a MS-like scheme. It is established that a special choice of the gauge parameter $\xi=-3$ generalizes the standard "naive nonabelianization" approximation. The solutions are obtained to the ER-BL evolution equation (taken at the "all loop" improved kernel), which are in form similar to one-loop solutions. A consequence for QCD descriptions of hard processes and the benefits and incompleteness of the approach are briefly discussed.Comment: 13 pages, revtex, 2 figures are enclosed as eps-file, the text style and figures are corrected following version, accepted for publication to Phys. Rev.

A Revision Of The Leaf Beetles Of The Poorly Known Chrysolina (Sahlbergiana) Species-Group In The Subgenus Pezocrosita (Coleoptera, Chrysomelidae)

Abstract: The subgenus Pezocrosita Jacobson, 1901, genus Chrysolina Motschulsky, 1860, currently includes 38 species, being divided into 7 species-groups. Among them, the Chrysolina (sahlbergiana) group remains the least studied, although it comprises the type species of the subgenus. The latter, Chrysolina sahlbergiana (Jacobson, 1901a), is shown to encompass 2 subspecies: Ch. sahlbergiana sahlbergiana and Ch. sahlbergiana jacobsoni (Lopatin, 1970). An amended description of Chrysolina hyperboreica Mikhailov, 2002, a local species endemic to the northern Ural Mountains within Sverdlovsk Province and previously known only from the male holotype, is given based on new material. A new species, Ch. korgonicasp. n., is described from western Altai. A key is given to all the four species of the group. The relict character of the Chrysolina (sahlbergiana) group is discussed based on disjunct distributions of its species and their associations with the former tundra-steppe communities. © 2021, Pleiades Publishing, Ltd

Numerical modelling of post-seismic rupture propagation after the Sumatra 26.12.2004 earthquake constrained by GRACE gravity data

In the last decades, the development of the surface and satellite geodetic and geophysical observations brought a new insights into the seismic cycle, documenting new features of inter-, co-, and post-seismic processes. In particular since 2002 satellite mission GRACE provides monthly models of the global gravity field with unprecedented accuracy showing temporal variations of the Earth's gravity field, including those caused by mass redistribution associated with earthquake processes. When combined with GPS measurements, these new data have allowed to assess the relative importance of afterslip and viscoelastic relaxation after the Sumatra 26.12.2004 earthquake. Indeed the observed post-seismic crustal displacements were fitted well by a viscoelastic relaxation model assuming Burgers body rheology for the asthenosphere (60-220 km deep) with a transient viscosity as low as 4× 1017 Pas and constant∼1019 Pas steady state viscosity in the 60-660-km depth range. However, even the low-viscosity asthenosphere provides the amplitude of strain which gravity effect does not exceed 50 per cent of the GRACE gravity variations, thus additional localized slip of about 1 m was suggested at downdip extension of the coseismic rupture. Post-seismic slip at coseismic rupture or its downdip extension has been suggested by several authors but the mechanism of the post-seismic fault propagation has never been investigated numerically. Depth and size of localized slip area as well as rate and time decay during the post-seismic stage were either assigned a priory or estimated by fitting real geodesy or gravity data. In this paper we investigate post-seismic rupture propagation by modelling two consequent stages. First, we run a long-term, geodynamic simulation to self-consistently produce the initial stress and temperature distribution. At the second stage, we simulate a seismic cycle using results of the first step as initial conditions. The second short-term simulation involves three substeps, including additional stress accumulation after part of the subduction channel was locked; spontaneous coseismic slip; formation and development of damage zones producing afterslip. During the last substep post-seismic stress leads to gradual∼1 m slip localized at three faults around∼100-km downdip extension of the coseismic rupture. We used the displacement field caused by the slip to calculate pressure and density variations and to simulate gravity field variations. Wavelength of calculated gravity anomaly fits well to that of the real data and its amplitude provides about 60 per cent of the observed GRACE anomaly. Importantly, the surface displacements caused by the estimated afterslip are much smaller than those registered by GPS networks. As a result cumulative effect of Burgers rheology viscoelastic relaxation (which explains measured GPS displacements and about a half of gravity variations) plus post-seismic slip predicted by damage rheology model (which causes much smaller surface displacements but provides another half of the GRACE gravity variations) fits well to both sets of the real data. Hence, the presented numerical modelling based on damage rheology supports the process of post-seismic downdip rupture propagation previously hypothesized from the GRACE gravity dat