298 research outputs found

    Classification of Perm krai areas according to prospectivity for oil fields acquisition

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    In modern conditions keeping high performance in oil exploration work implies development of the areas forming an unallocated subsoil reserve fund by acquiring licenses for the new oil fields.­ Resource potential of the current licence blocks depletes as good structures are surveyed and deposits are put into operation, hence exploration is required in the new areas. Oilfield exploration efficiency largely depends on resource potential of the plots, the state of their geologic and geophysic exploration, distance from infrastructure facilities, geologic parameters and readiness of developers to carry out survey and uncover the plots' potential. The licensing mechanism involves regular publication by governing bodies of large lists of the plots for them to be developed within a certain time period. It is crucial for developers to filter these lists to ignore least prospective plots and select the most prospective to perform a comprehensive assessment prior to acquisition. To minimize the time expenses and assess the largest amount of plots possible a filtering procedure has to be simple, transparent and based on the minimum number of quantitative criteria. The present paper describes a technique to assess prospectivity of oil plots in Perm krai by using probability-statistical methods and processing exploration data for the previous years

    Iron based superconductors: magnetism, superconductivity and electronic structure

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    Angle resolved photoemission spectroscopy (ARPES) reveals the features of the electronic structure of quasi-two-dimensional crystals, which are crucial for the formation of spin and charge ordering and determine the mechanisms of electron-electron interaction, including the superconducting pairing. The newly discovered iron based superconductors (FeSC) promise interesting physics that stems, on one hand, from a coexistence of superconductivity and magnetism and, on the other hand, from complex multi-band electronic structure. In this review I want to give a simple introduction to the FeSC physics, and to advocate an opinion that all the complexity of FeSC properties is encapsulated in their electronic structure. For many compounds, this structure was determined in numerous ARPES experiments and agrees reasonably well with the results of band structure calculations. Nevertheless, the existing small differences may help to understand the mechanisms of the magnetic ordering and superconducting pairing in FeSC.Comment: Invited Revie

    A specialized isotope mass spectrometer for noninvasive diagnostics of Helicobacter pylori infection in human beings

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    A specialized isotope mass spectrometer for noninvasive diagnostics of Helicobacter pylori infection in human beings based on the carbon-13 isotope breath test has been designed and constructed. Important stages of the work included (i) calculating a low-aberration mass analyzer, (ii) manufacturing and testing special gas inlet system, and (iii) creating a small-size collector of ions. The proposed instrument ensures 13C/12C isotopic ratio measurement to within 1.7‰ (pro mille) accuracy, which corresponds to requirements for a diagnostic tool. Preliminary medical testing showed that the mass spectrometer is applicable to practical diagnostics. The instrument is also capable of measuring isotopic ratios of other light elements, including N, O, B (for BF2+ ions), Ar, Cl, and

    PCT, spin and statistics, and analytic wave front set

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    A new, more general derivation of the spin-statistics and PCT theorems is presented. It uses the notion of the analytic wave front set of (ultra)distributions and, in contrast to the usual approach, covers nonlocal quantum fields. The fields are defined as generalized functions with test functions of compact support in momentum space. The vacuum expectation values are thereby admitted to be arbitrarily singular in their space-time dependence. The local commutativity condition is replaced by an asymptotic commutativity condition, which develops generalizations of the microcausality axiom previously proposed.Comment: LaTeX, 23 pages, no figures. This version is identical to the original published paper, but with corrected typos and slight improvements in the exposition. The proof of Theorem 5 stated in the paper has been published in J. Math. Phys. 45 (2004) 1944-195

    Quasi-periodic oscillations of small-scale magnetic structures and a specific method for measuring the differential rotation of the Sun

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    The SDO/HMI data with an angular resolution of 1 arcsec have been used to explore the differential rotation on the Sun, using an original p2p effect on the basis of the movement of small-scale magnetic structures in the photosphere of the Sun. It is shown that a stable p2p artifact inherent in the SDO/HMI data can be an effective tool for measuring the speed of various tracers on the Sun. In particular, in combination with the Fourier analysis, it allows us to investigate the differential rotation of the Sun at various latitudes. The differential rotation curve obtained from the SDO/HMI magnetograms by this method is in good agreement with the curves obtained earlier from ground-based observations

    QUASI-PERIODIC OSCILLATIONS OF SMALL-SCALE MAGNETIC STRUCTURES AND A SPECIFIC METHOD FOR MEASURING THE DIFFERENTIAL ROTATION OF THE SUN

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    The SDO/HMI data with an angular resolution of 1 arcsec have been used to explore the differential rotation on the Sun, using an original p2p effect on the basis of the movement of small-scale magnetic structures in the photosphere of the Sun. It is shown that a stable p2p artifact inherent in the SDO/HMI data can be an effective tool for measuring the speed of various tracers on the Sun. In particular, in combination with the Fourier analysis, it allows us to investigate the differential rotation of the Sun at various latitudes. The differential rotation curve obtained from the SDO/HMI magnetograms by this method is in good agreement with the curves obtained earlier from groundbased observations

    Projective Hilbert space structures at exceptional points

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    A non-Hermitian complex symmetric 2x2 matrix toy model is used to study projective Hilbert space structures in the vicinity of exceptional points (EPs). The bi-orthogonal eigenvectors of a diagonalizable matrix are Puiseux-expanded in terms of the root vectors at the EP. It is shown that the apparent contradiction between the two incompatible normalization conditions with finite and singular behavior in the EP-limit can be resolved by projectively extending the original Hilbert space. The complementary normalization conditions correspond then to two different affine charts of this enlarged projective Hilbert space. Geometric phase and phase jump behavior are analyzed and the usefulness of the phase rigidity as measure for the distance to EP configurations is demonstrated. Finally, EP-related aspects of PT-symmetrically extended Quantum Mechanics are discussed and a conjecture concerning the quantum brachistochrone problem is formulated.Comment: 20 pages; discussion extended, refs added; bug correcte

    Magnetohydrodynamic equilibria of a cylindrical plasma with poloidal mass flow and arbitrary cross section shape

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    The equilibrium of a cylindrical plasma with purely poloidal mass flow and cross section of arbitrary shape is investigated within the framework of the ideal MHD theory. For the system under consideration it is shown that only incompressible flows are possible and, conscequently, the general two dimensional flow equilibrium equations reduce to a single second-order quasilinear partial differential equation for the poloidal magnetic flux function ψ\psi, in which four profile functionals of ψ\psi appear. Apart from a singularity occuring when the modulus of Mach number associated with the Alfv\'en velocity for the poloidal magnetic field is unity, this equation is always elliptic and permits the construction of several classes of analytic solutions. Specific exact equlibria for a plasma confined within a perfectly conducting circular cylindrical boundary and having i) a flat current density and ii) a peaked current density are obtained and studied.Comment: Accepted to Plasma Physics & Controlled Fusion, 14 pages, revte

    Long quasi-periodic oscillations of the faculae and pores

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    Aims. The main goal of this work is to analyze the structural and temporal evolution of small-scale magnetic structures (SSMSs) observed in the solar atmosphere, such as solitary faculae and pores, and reveal long quasi-periodic oscillations of these structures.Methods. The statistical method of regression analysis and the wavelet transform were used to obtain the periods of oscillations and dependences between the parameters of magnetic structures and periods of oscillations.Results. Long-period oscillations with periods in the interval of 18-260 min are found for the structurally stable phase of SSMSs at the level of the solar photosphere. These long-period oscillations were interpreted as natural oscillations of the structurally stable long-lived magnetic structures around their equilibrium position. These oscillations, which are of similar nature, are observed in the chromospheric bright formations associated with photospheric SSMSs. Dependences between the magnetic field and the continuum intensity of the facula elements were found. It is shown that the continuum intensity of a SSMS decreases when its magnetic field increases
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