298 research outputs found
Classification of Perm krai areas according to prospectivity for oil fields acquisition
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
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
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
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
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
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
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
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 , in which four profile functionals of 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
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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