408 research outputs found

    Enhanced magneto-optical Kerr effect in oxidized Co thin films

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    We have studied the structural and magneto-optical properties of postdeposition oxidized Co thin films. The oxidization process leads to the formation of a double-layered structure of fcc Co3O4 on top of metallic Co. The magneto-optical Kerr effect (MOKE), measured in the range 0.8 eV ⩽ EPh ⩽ 5.5 eV reveals characteristic dependencies of the MOKE spectra on annealing temperature and time. In particular, we observe resonance-type enhancements of the Kerr effects by up to a factor of 10 compared with unannealed metallic Co. The experimental data are quantitatively reproduced by bilayer optical stack calculations.One of the authors ~B.R.! has been gratefully supported by means of the Deutsche Forschungsgemeinschaft. One of the authors ~G.A.! thanks the Ministerio De Educacion y Ciencia ~Spain! for financial support.Peer reviewe

    Выбор оптимальных методов технологии и контроля при проведении гидроразрыва пласта ( на примере Самотлорского месторождения)

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    Представлен анализ текущего состояния разработки месторождения и основных методов повышения эффективности разработки. Произведен выбор оптимальных технологий с учетом их фильтрационноемкостных свойств. Показано влияние синтетического полимера на свойства проводимости трещин поле стадий ГРП.The analysis of the current state of development of the field and the main methods to improve development efficiency is presented. The selection of optimal technologies with taking into account their filtration-capacitive properties. The effect of synthetic polymer on the conductivity properties of fractures in the field of hydraulic fracturing stages

    Замена электродвигателя ПЭН турбоприводом на Кемеровской ТЭЦ

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    В данной работе рассматривается возможность замены электродвигателя ПЭН турбоприводом на Кемеровской ТЭЦ, с установкой турбопривода на существующий фундамент. Целью работы является оценка возможности увеличения отпуска электроэнергии от станции в результате уменьшения затрат на собственные нужды и повышение маневренности ТЭЦ.In this paper we consider the possibility of replacing the turbine drive motor PEN to Kemerovo CHP , with the installation of turbine drive on the existing foundation. The aim is to assess the possibility of increasing the supply of electric power from the plant by reducing the costs of their own needs and improving maneuverability CHP

    Asteroseismology with the WIRE satellite. I. Combining Ground- and Space-based Photometry of the Delta Scuti Star Epsilon Cephei

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    We have analysed ground-based multi-colour Stromgren photometry and single-filter photometry from the star tracker on the WIRE satellite of the delta scuti star Epsilon Cephei. The ground-based data set consists of 16 nights of data collected over 164 days, while the satellite data are nearly continuous coverage of the star during 14 days. The spectral window and noise level of the satellite data are superior to the ground-based data and this data set is used to locate the frequencies. However, we can use the ground-based data to improve the accuracy of the frequencies due to the much longer time baseline. We detect 26 oscillation frequencies in the WIRE data set, but only some of these can be seen clearly in the ground-based data. We have used the multi-colour ground-based photometry to determine amplitude and phase differences in the Stromgren b-y colour and the y filter in an attempt to identify the radial degree of the oscillation frequencies. We conclude that the accuracies of the amplitudes and phases are not sufficient to constrain theoretical models of Epsilon Cephei. We find no evidence for rotational splitting or the large separation among the frequencies detected in the WIRE data set. To be able to identify oscillation frequencies in delta scuti stars with the method we have applied, it is crucial to obtain more complete coverage from multi-site campaigns with a long time baseline and in multiple filters. This is important when planning photometric and spectroscopic ground-based support for future satellite missions like COROT and KEPLER.Comment: 13 pages, 12 figures, 4 tables. Fig. 4 reduced in quality. Accepted by A&

    High Avidity dsDNA Autoantibodies in Brazilian Women with Systemic Lupus Erythematosus: Correlation with Active Disease and Renal Dysfunction

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    We investigated in Brazilian women with SLE the prevalence and levels of high avidity (HA) dsDNA antibodies and tested their correlation with lupus activity and biomarkers of renal disease. We also compared these correlations to those observed with total dsDNA antibodies and antibodies against nucleosome (ANuA). Autoantibodies were detected by ELISA, while C3 and C4 levels were determined by nephelometry. Urine protein/creatinine ratio was determined, and lupus activity was measured by SLEDAI-2K. The prevalence of total and HA dsDNA antibodies was similar to but lower than that verified for ANuA. The levels of the three types of antibodies were correlated, but the correlation was more significant between HA dsDNA antibodies and ANuA. High avidity dsDNA antibodies correlated positively with ESR and SLEDAI and inversely with C3 and C4. Similar correlations were observed for ANuA levels, whereas total dsDNA antibodies only correlated with SLEDAI and C3. The levels of HA dsDNA antibodies were higher in patients with proteinuria, but their levels of total dsDNA antibodies and ANuA were unaltered. High avidity dsDNA antibodies can be found in high prevalence in Brazilian women with SLE and are important biomarkers of active disease and kidney dysfunction

    Abundance analysis of targets for the COROT / MONS asteroseimology missions I. Semi-automatic abundance analysis of the gamma Dor star HD 49434

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    One of the goals of the ground-based support program for the COROT and MONS/Roemer satellite missions is to select and characterise suitable target stars for the part of the missions dedicated to asteroseismology. While the global atmospheric parameters may be determined with good accuracy from the Stromgren indices, careful abundance analysis must be made for the proposed main targets. This is a time consuming process considering the long list of primary and secondary targets. We have therefore developed new software called VWA for this task. The VWA automatically selects the least blended lines from the atomic line database VALD, and consequently adjusts the abundance in order to find the best match between the calculated and observed spectra. The variability of HD 49434 was discovered as part of COROT ground-based support observations. Here we present a detailed abundance analysis of HD 49434 using VWA. For most elements we find abundances somewhat below the Solar values, in particular we find [Fe/H] = -0.13(14). We also present the results from the study of the variability that is seen in spectroscopic and photometric time series observations. From the characteristics of the variation seen in photometry and in the line profiles we propose that HD 49434 is a variable star of the gamma Doradus type.Comment: 10 pages, 6 figure

    Effects of parental acclimation and energy limitation in response to high CO2 exposure in Atlantic cod

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    Ocean acidification (OA), the dissolution of excess anthropogenic carbon dioxide in ocean waters, is a potential stressor to many marine fish species. Whether species have the potential to acclimate and adapt to changes in the seawater carbonate chemistry is still largely unanswered. Simulation experiments across several generations are challenging for large commercially exploited species because of their long generation times. For Atlantic cod (Gadus morhua), we present first data on the effects of parental acclimation to elevated aquatic CO2 on larval survival, a fundamental parameter determining population recruitment. The parental generation in this study was exposed to either ambient or elevated aquatic CO2 levels simulating end-of-century OA levels (~1100 µatm CO2) for six weeks prior to spawning. Upon fully reciprocal exposure of the F1 generation, we quantified larval survival, combined with two larval feeding regimes in order to investigate the potential effect of energy limitation. We found a significant reduction in larval survival at elevated CO2 that was partly compensated by parental acclimation to the same CO2 exposure. Such compensation was only observed in the treatment with high food availability. This complex 3-way interaction indicates that surplus metabolic resources need to be available to allow a transgenerational alleviation response to ocean acidification
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