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Mathematical analysis of time series is shown to be applicable to assessing the factors governing benz[a]pyrene concentration in the Ufa River water. The contributions of the deterministic and random components to the total benz[a]pyrene concentration. Seasonal increase (October–January, March–April) and decrease (February, May–September) in benz[a]pyrene concentrations in the Ufa River are established. 相似文献
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The effect of the curvature of open magnetic field lines on the generation of electric fields in radio pulsars is considered in the framework of a Goldreich-Julian model, for both a regime with a free outflow of electrons from the neutron-star surface and the case of a small thermoemission current. An expression for the electron thermoemission current in a strong magnetic field is derived. The electric field associated with the curvature of the magnetic flux tubes is comparable to the field generated by the relativistic dragging of the inertial frames. 相似文献
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We consider the influence of a non-dipolar magnetic field on the gamma-ray emission from the polar regions of a radio pulsar. The pulsar is treated in a Goldreich-Julian model with a free flow of charge from the surface of the neutron star. When finding the intensity of the gamma-ray radiation of the pulsar tube, both curvature gamma-ray radiation from the primary electrons and non-resonance inverse Compton scattering of thermal photons from the polar cap on primary electrons are taken into account. When finding the height of the upper plate of the pulsar diode, we included only positrons created by the curvature radiation of primary electrons. We assumed that the polar cap is heated by the return positron current. The influence on the gamma-ray emission of variations in both the radius of curvature of the magnetic force lines and in the electric field due to the non-dipolarity of the magnetic field were taken into account. The presence of even weak non-dipolarity of the magnetic field leads to a sharp decrease in the intensity of the gamma-ray emission from the pulsar tube at energies 1–100 MeV, while the intensity of the inverse Compton radiation (at energies 1–100 GeV) varies only relatively weakly. 相似文献
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One of the effective mechanisms of neutrino energy losses in red giants, pre-supernovae and in the cores of white dwarfs is the emission of neutrino–antineutrino pairs in the process of plasmon decay. In this paper, we numerically calculate the emissivity due to plasmon decay in a wide range of temperatures 107 –1011 K and densities (2 × 102 –1014 ) g cm−3 . Numerical results are approximated by convenient analytical expressions. We also calculate and approximate by analytical expressions the neutrino luminosity of white dwarfs due to plasmon decay, as a function of their mass and internal temperature. This neutrino luminosity depends on the chemical composition of white dwarfs only through the parameter μe (the net number of baryons per electron) and is the dominant neutrino luminosity in all white dwarfs at the neutrino cooling stage. 相似文献
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Innokenty Kantor Leonid Dubrovinsky Catherine McCammon Anastasia Kantor Sakura Pascarelli Giuliana Aquilanti Wilson Crichton Maurizio Mattesini Rajeev Ahuja Jailton Almeida Vadim Urusov 《Physics and Chemistry of Minerals》2006,33(1):35-44
Combined X-ray powder diffraction, Mössbauer, and XANES spectroscopy in situ experiments revealed the transformation of cubic (Mg0.8Fe0.2)O ferropericlase to a rhombohedrally distorted phase at 35(1) GPa and room temperature. The Mössbauer spectroscopy results show that the rhombohedral distortion does not involve magnetic ordering. Combined with data from the literature, our results imply that the cubic to rhombodedral transition occurs in (Mg,Fe)O under conditions of non-hydrostatic stress over a wide range of composition (0.2≤x Fe≤1). 相似文献
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The effect of curvature of open magnetic-field tubes on the death lines of radio pulsars is studied. The solution is obtained in the framework of a Goldreich-Julian model for both dipolar and asymmetric magnetic fields. The tube-axis curvature can shift the death line appreciably toward either longer or shorter periods. If the field is dipolar and gamma rays are generated by the inverse Compton effect, the formation of secondary plasma is more efficient near the death line. In the case of an asymmetric magnetic field, the generation of radio emission beyond the tube of open field lines is possible. 相似文献
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L. N. Gagarina M. Yu. Vozhdaeva L. I. Kantor I. A. Mel’nitskii N. V. Trukhanova 《Water Resources》2009,36(5):513-517
It is shown that gasolines in water can be identified by the relative concentrations of the major aromatic components that
are most stable and typical of gasolines (references components): meta- + para-ethyltoluenes, 1,3,5-trimethylbenzene, ortho-ethyltoluenes,
and 1,2,4-trimethylbenzene. Three most widespread grades of gasoline are used as an example to show that the lower detection
limit of gasoline water pollution by chromatographic analysis with dynamic concentration of sample is 0.01 mg/dm3. 相似文献
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Increasingly, health outcomes are tied to nutritional opportunities based on the availability of foods and cultural patterns of consumption. This paper demonstrates how Esri Community Analyst can help in identifying at-risk communities. The methodology that results argues a means by which national data made available by Esri in a “one-stop shop” can be utilized in a simplified, user-friendly way to identify specific populations with higher prevalence of certain diseases and areas where nutritional needs are likely unmet. For demonstration purposes, this paper presents a case study for South Carolina, USA. 相似文献
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