TOPOGRAPHIC-GEODETIC AND CARTOGRAPHIC SUPPORT OF THE ARCTIC ZONE OF THE RUSSIAN FEDERATION

A version of the project of the concept of topographic, geodetic and cartographic support of the Arctic zone of the Russian Federation based on the use of modern means and tools is presented, including its content. The results of the development in the Arctic, carried out with the participation of the authors in 1961-1967 and 1975-1992, are presented in detail. The strategic importance and great attention of the state structures to the development of the Arctic zone is underlined. The key moments of the development of topographic, geodetic and cartographic support for this region are given. The role of leading research institutes in this process is shown. The proposed concept includes six stages. When creating a planimetric geodetic base, the authors recommend an alternative innovative algorithm for determining the height H without first calculating the latitude B and use only satellite measurements. The extremely important question of converting geodetic coordinates B, L into rectangular plane coordinates x, y is considered. For the territory of the Russian Federation new developments are proposed, they use data from satellite determinations, a new approach to the determination of normal heights and the conversion of rectangular space coordinates into rectangular plane coordinates necessary for mapping. The required regulations of reference documentation for the topographic survey of the shelf are shown. The importance of implementing the concept in connection with the definition of the outer boundary of the continental shelf of the Arctic Ocean is shown

Metals in high magnetic field: a new universality class of Fermi liquids

Parquet equations, describing the competition between superconducting and density-wave instabilities, are solved for a three-dimensional isotropic metal in a high magnetic field when only the lowest Landau level is filled. In the case of a repulsive interaction between electrons, a phase transition to the density-wave state is found at finite temperature. In the opposite case of attractive interaction, no phase transition is found. With decreasing temperature $T$, the effective vertex of interaction between electrons renormalizes toward a one-dimensional limit in a self-similar way with the characteristic length (transverse to the magnetic field) decreasing as $\ln^{-1/6}(\omega_c/T)$ ($\omega_c$ is a cutoff). Correlation functions have new forms, previously unknown for conventional one-dimensional or three-dimensional Fermi-liquids.Comment: 13 pages + 4 figures (included

Plasmon phonon modes and optical resonances in n-GaN

We study theoretically and experimentally transverse and longitudinal electromagnetic waves in n-GaN epitaxial layers. The studies are carried out on the epitaxial layers with various doping levels. Simulation of the reflectivity and absorptivity spectra is performed in a wide frequency range. Additionally, the radiation emission spectra are simulated for various temperatures of the GaN epitaxial layer. It is shown that the resonance peculiarities of the optical spectra are located closely to the frequencies of the coupled plasmon phonon modes. Experimental studies of the reflectivity spectra have been performed in the spectral range 2-20 THz. The experimental spectra are well fitted by the simulated ones and can be used for contactless determination of the electron concentration and mobility in GaN epitaxial layers. The experimental and theoretical results of the present work provide insights for the development of GaN-based devices aimed to absorb/emit terahertz or mid infrared radiation selectively.Peer reviewe

Effects of an External Magnetic Field on the Interband and Intraband Optical Properties of an Asymmetric Biconvex Lens-Shaped Quantum Dot

The theoretical investigation of interband and intraband transitions in an asymmetric biconvex lens-shaped quantum dot are considered in the presence of an external magnetic field. The selection rules for intraband transitions are obtained. The behaviors of linear and nonlinear absorption and photoluminescence spectra are observed for different temperatures and magnetic field strengths. The second and third harmonic generation coefficients as a function of the photon energy are examined both in the absence and presence of an external magnetic field