Large-format laser range

New principle of large format scanning laser range construction for mobile object navigation realized on the basis of piezoelectric drive of laser beam inclination control has been suggested. Optimal drive parameters and laws of controlling range laser beam scanning were determined. Limiting angular format by azimuth coordinate (the most important one for navigation of water and ground mobile objects) up to hemisphere size is 180о. The proposed principle is approved in adaptive television automatic system, means of control and diagnostics of laser beam state at stochastic influenc

Bending of a circular plate with a radial crack whose flanks are in contact

Bending of the circle isotropic plate with radial crack with contact shores is investigated. For want of solving of a problem was considered, that the shores of a crack come in contact on the upper basis on all it’s length. A solving of a problem constructed with use of methods of the theory of functions of a complex variable and complex potentials. The system of singular integral equations was untied numerically with the help of method of mechanical quadratures. The numerical analysis of a problem is conducted, because of which constructed graphic dependence of contact pressure and moments intensity factor and strain intensity factor

Diagrammatic analysis of the Hubbard model:Stationary property of the thermodynamic potential

Diagrammatic approach proposed many years ago for strong correlated Hubbard model is developed for analyzing of the thermodynamic potential properties. The new exact relation between such renormalized quantities as thermodynamic potential, one-particle propagator and correlation function is established. This relation contains additional integration of the one-particle propagator by the auxiliary constant. The vacuum skeleton diagrams constructed from irreducible Green's functions and tunneling propagator lines are determined and special functional is introduced. The properties of such functional are investigated and its relation to the thermodynamic potential is established. The stationary properties of this functional with respect to first order changing of the correlation function is demonstrated and as a consequence the stationary properties of the thermodynamic potential is proved.Comment: 6 pages, 4 figure

Interaction of strongly correlated electrons and acoustical phonons

We investigate the interaction of correlated electrons with acoustical phonons using the extended Hubbard-Holstein model in which both, the electron-phonon interaction and the on-site Coulomb repulsion are considered to be strong. The Lang-Firsov canonical transformation allows to obtain mobile polarons for which a new diagram technique and generalized Wick's theorem is used. This allows to handle the Coulomb repulsion between the electrons emerged into a sea of phonon fields (\textit{phonon clouds}). The physics of emission and absorption of the collective phonon-field mode by the polarons is discussed in detail. Moreover, we have investigated the different behavior of optical and acoustical phonon clouds when propagating through the lattice. In the strong-coupling limit of the electron-phonon interaction, and in the normal as well as in the superconducting phase, chronological thermodynamical averages of products of acoustical phonon-cloud operators can be expressed by one-cloud operator averages. While the normal one-cloud propagator has the form of a Lorentzian, the anomalous one is of Gaussian form and considerably smaller. Therefore, the anomalous electron Green's functions can be considered to be more important than corresponding polarons functions, i.e., pairing of electrons without phonon-clouds is easier to achieve than pairing of polarons with such clouds.Comment: : 28 pages, 9 figures, revtex4. Invited paper for a special issue of Low Temperature Physics dedicated to the 20th anniversary of HTS

Strong interaction of correlated electrons with phonons: Exchange of phonon clouds by polarons

We investigate the interaction of strongly correlated electrons with phonons in the frame of the Hubbard-Holstein model. The electron-phonon interaction is considered to be strong and is an important parameter of the model besides the Coulomb repulsion of electrons and band filling. This interaction with the nondispersive optical phonons has been transformed to the problem of mobile polarons by using the canonical transformation of Lang and Firsov. We discuss in particular the case for which the on-site Coulomb repulsion is exactly cancelled by the phonon-mediated attractive interaction and suggest that polarons exchanging phonon clouds can lead to polaron pairing and superconductivity. It is then the frequency of the collective mode of phonon clouds being larger than the bare frequency, which determines the superconducting transition temperature.Comment: 23 pages, Submitted to Phys. Rev.

A rare case of tuberculous salpingitis

The objective of this study was to give an overview of a rare case of tuberculosis of the left fallopian tube in postmenopausal women. It is known that the isolated tuberculous salpingitis without spreading to the endometrium is extremely rare case. In our case, it simulated a cancer of appendages at the late stages that were proved by the increased level of CA-125. This fact as well as the macroscopic image of the left fallopian tube was incorrectly considered by the clinicians as a malignant neoplasm of fallopian tube. However, after pathomorphological examination of postoperative samples during histological study, the main method of verification of the diagnosis, revealed the specific granulomas in the samples that indicate the tubercular inflammation. It was considered by clinical and laboratory as data secondary focus