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Sample records for line fe xiv

  1. Observations of Fe XIV Line Intensity Variations in the Solar Corona During the 21 August 2017 Solar Eclipse

    Science.gov (United States)

    Johnson, Payton; Ladd, Edwin

    2018-01-01

    We present time- and spatially-resolved observations of the inner solar corona in the 5303 Å line of Fe XIV, taken during the 21 August 2017 solar eclipse from a field observing site in Crossville, TN. These observations are used to characterize the intensity variations in this coronal emission line, and to compare with oscillation predictions from models for heating the corona by magnetic wave dissipation.The observations were taken with two Explore Scientific ED 102CF 102 mm aperture triplet apochromatic refractors. One system used a DayStar custom-built 5 Å FWHM filter centered on the Fe XIV coronal spectral line and an Atik Titan camera for image collection. The setup produced images with a pixel size of 2.15 arcseconds (~1.5 Mm at the distance to the Sun), and a field of view of 1420 x 1060 arcseconds, covering approximately 20% of the entire solar limb centered near the emerging sunspot complex AR 2672. We obtained images with an exposure time of 0.22 seconds and a frame rate of 2.36 Hz, for a total of 361 images during totality.An identical, co-aligned telescope/camera system observed the same portion of the solar corona, but with a 100 Å FWHM Baader Planetarium solar continuum filter centered on a wavelength of 5400 Å. Images with an exposure time of 0.01 seconds were obtained with a frame rate of 4.05 Hz. These simultaneous observations are used as a control to monitor brightness variations not related to coronal line oscillations.

  2. High-resolution Laboratory Measurements of Coronal Lines near the Fe IX Line at 171 Å

    Science.gov (United States)

    Beiersdorfer, Peter; Träbert, Elmar

    2018-02-01

    We present high-resolution laboratory measurements in the spectral region between 165 and 175 Å that focus on the emission from various ions of C, O, F, Ne, S, Ar, Fe, and Ni. This wavelength region is centered on the λ171 Fe IX channel of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory, and we place special emphasis on the weaker emission lines of Fe IX predicted in this region. In general, our measurements show a multitude of weak lines missing in the current databases, where the emission lines of Ni are probably most in need of further identification and reclassification. We also find that the wavelengths of some of the known lines need updating. Using the multi-reference Møller–Plesset method for wavelength predictions and collisional-radiative modeling of the line intensities, we have made tentative assignments of more than a dozen lines to the spectrum of Fe IX, some of which have formerly been identified as Fe VII, Fe XIV, or Fe XVI lines. Several Fe features remain unassigned, although they appear to be either Fe VII or Fe X lines. Further work will be needed to complete and correct the spectral line lists in this wavelength region.

  3. Fabry-Perot observations of [FeX] in the Cygnus Loop and IC443

    International Nuclear Information System (INIS)

    Ballet, J.; Rothenflug, R.; Soutoul, A.; Caplan, J.

    1988-01-01

    The authors present the first results of an observational program of SNRs in the coronal lines of [FeX] and [FeXIV] using Fabry--Perot spectrophotometer. These support previously published brightnesses

  4. Fine structure transitions in Fe XIV

    Science.gov (United States)

    Nahar, Sultana N.

    2013-07-01

    Results are reported for Fe XIV energy levels and transitions obtained from the ab initio relativistic Breit-Pauli R-matrix (BPRM) method. BPRM method developed under the Iron Project is capable of calculating very large number of fine structure energy levels and corresponding transitions. However, unlike in the atomic structure calculations, where levels are identified spectroscopically based on the leading percentage contributions of configurations, BPRM is incapable of such identification of the levels and hence the transitions. The main reason for it is that the percentage contributions can not be determined exactly from the large number of channels in the R-matrix space. The present report describes an identification method that uses considerations of quantum defects of channels, contributions of channel from outer regions, Hund's rule, and angular momenta algebra for addition and completeness of fine structure components. The present calculations are carried out using a close coupling wave function expansion that included 26 core excitations from configurations 2s22p63s2, 2s22p63s3p,2s22p63p2,2s22p63s3d, and 2s22p63p3d. A total of 1002 fine structure levels with n ⩽ 10, l⩽9, and 0.5 ⩽J⩽ 9.5 with even and odd parities and the corresponding 130,520 electric dipole allowed (E1) fine structure transitions, a most complete set for astrophysical modelings of spectral analysis and opacities, is presented. Large number of new energy levels are found and identified. The energies agree very well, mostly in less than 1% with the highest being 1.9%, with the 68 observed fine structure levels. While the high lying levels may have some uncertainty, an overall accuracy of energy levels should be within 10%. BPRM transitions have been benchmarked with the existing most accurate calculated transition probabilities with very good agreement for most cases. Based on the accuracy of the method and comparisons, most of the transitions can be rated with A (⩽10%) to C (

  5. Laboratory calibration of density-dependent lines in the extreme ultraviolet spectral region

    Science.gov (United States)

    Lepson, J. K.; Beiersdorfer, P.; Gu, M. F.; Desai, P.; Bitter, M.; Roquemore, L.; Reinke, M. L.

    2012-05-01

    We have been making spectral measurements in the extreme ultraviolet (EUV) from different laboratory sources in order to investigate the electron density dependence of various astrophysically important emission lines and to test the atomic models underlying the diagnostic line ratios. The measurement are being performed at the Livermore EBIT-I electron beam ion trap, the National Spherical Torus Experiment (NSTX) at Princeton, and the Alcator C-Mod tokamak at the Massachusetts Institute of Technology, which together span an electron density of four orders of magnitude and which allow us to test the various models at high and low density limits. Here we present measurements of Fe XXII and Ar XIV, which include new data from an ultra high resolution (λ/Δλ >4000) spectrometer at the EBIT-I facility. We found good agreement between the measurements and modeling calculations for Fe XXII, but poorer agreement for Ar XIV.

  6. Temperature diagnostic line ratios of Fe XVII

    International Nuclear Information System (INIS)

    Raymond, J.C.; Smith, B.W.; Los Alamos National Lab., NM)

    1986-01-01

    Based on extensive calculations of the excitation rates of Fe XVII, four temperature-sensitive line ratios are investigated, paying special attention to the contribution of resonances to the excitation rates and to the contributions of dielectronic recombination satellites to the observed line intensities. The predictions are compared to FPCS observations of Puppis A and to Solar Maximum Mission (SMM) and SOLEX observations of the sun. Temperature-sensitive line ratios are also computed for emitting gas covering a broad temperature range. It is found that each ratio yields a differently weighted average for the temperature and that this accounts for some apparent discrepancies between the theoretical ratios and solar observations. The effects of this weighting on the Fe XVII temperature diagnostics and on the analogous Fe XXIV/Fe XXV satellite line temperature diagnostics are discussed. 27 references

  7. An extreme Fe II emitter the narrow line quasar PHL 1092

    CERN Document Server

    Bergeron, J

    1980-01-01

    A search for Fe II emission in a sample of radio-quiet quasars has revealed the outstanding properties of PHL 1092. Intense Fe II lines dominate the entire spectrum, and the Fe II UV multiplets are nearly as strong as the optical ones. In contrast the extreme weakness of the Balmer and Mg II lines is striking. For the first time, Fe I lines are identified in an extra-galactic object. The lines are narrow, with a FWHM of 1300 km s/sup -1/. The presence of Fe II UV lines and Fe I lines from the ground state requires moderate column densities. However Fe/sup 0/ can exist only in a region completely shielded from the UV continuum. The weakness of Mg II and H beta relative to Fe II lines is best explained by their thermalization. The emitting region is of high electron density n/sub e/ approximately=10/sup 12/ cm/sup -3/, low temperature T approximately=10000K, and has an optical depth in the Fe II UV lines tau /sub UV/ approximately=10/sup 3/-10/sup 4/. It is speculated that for higher densities all the lines wou...

  8. Extreme Ultraviolet Emission Lines of Iron Fe XI-XIII

    Science.gov (United States)

    Lepson, Jaan; Beiersdorfer, P.; Brown, G. V.; Liedahl, D. A.; Brickhouse, N. S.; Dupree, A. K.

    2013-04-01

    The extreme ultraviolet (EUV) spectral region (ca. 20--300 Å) is rich in emission lines from low- to mid-Z ions, particularly from the middle charge states of iron. Many of these emission lines are important diagnostics for astrophysical plasmas, providing information on properties such as elemental abundance, temperature, density, and even magnetic field strength. In recent years, strides have been made to understand the complexity of the atomic levels of the ions that emit the lines that contribute to the richness of the EUV region. Laboratory measurements have been made to verify and benchmark the lines. Here, we present laboratory measurements of Fe XI, Fe XII, and Fe XIII between 40-140 Å. The measurements were made at the Lawrence Livermore electron beam ion trap (EBIT) facility, which has been optimized for laboratory astrophysics, and which allows us to select specific charge states of iron to help line identification. We also present new calculations by the Hebrew University - Lawrence Livermore Atomic Code (HULLAC), which we also utilized for line identification. We found that HULLAC does a creditable job of reproducing the forest of lines we observed in the EBIT spectra, although line positions are in need of adjustment, and line intensities often differed from those observed. We identify or confirm a number of new lines for these charge states. This work was supported by the NASA Solar and Heliospheric Program under Contract NNH10AN31I and the DOE General Plasma Science program. Work was performed in part under the auspices of the Department of Energy by Lawrence Livermore National Laboratory under Contract DEAC52-07NA27344.

  9. Infrared Fe II lines in Eta Carinae and a possible interpretation of infrared excesses

    International Nuclear Information System (INIS)

    Thackeray, A.D.

    1978-01-01

    The identification of very strong emission lines in the near infrared spectrum of Eta Carinae with newly recognised high-level transitions of Fe II raises the possibility that the infrared excesses of hot emission-line stars may be due to dielectronic recombination of Fe II. Johansson's Fe II lines also need to be considered in the interpretation of the infrared spectra of supernovae. (author)

  10. LARGE-AREA [Fe II] LINE MAPPING OF THE SUPERNOVA REMNANT IC 443 WITH THE IRSF/SIRIUS

    Energy Technology Data Exchange (ETDEWEB)

    Kokusho, Takuma; Nagayama, Takahiro; Kaneda, Hidehiro; Ishihara, Daisuke [Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Lee, Ho-Gyu; Onaka, Takashi, E-mail: kokusho@u.phys.nagoya-u.ac.jp [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2013-05-01

    We present the results of near-infrared (near-IR) [Fe II] line mapping of the supernova remnant IC 443 with IRSF/SIRIUS, using the two narrow-band filters tuned for the [Fe II] 1.257 {mu}m and [Fe II] 1.644 {mu}m lines. Covering a large area of 30' Multiplication-Sign 35', our observations reveal that [Fe II] filamentary structures exist all over the remnant, not only in an ionic shock shell, but also in a molecular shock shell and a central region inside the shells. With the two [Fe II] lines, we performed corrections for dust extinction to derive the intrinsic line intensities. We also obtained the intensities of thermal emission from the warm dust associated with IC 443, using the far- and mid-IR images taken with AKARI and Spitzer, respectively. As a result, we find that the [Fe II] line emission relative to the dust emission notably enhances in the inner central region. We discuss causes of the enhanced [Fe II] line emission, estimating the Fe{sup +} and dust masses.

  11. A Fe K Line in GRB 970508

    Science.gov (United States)

    Protassov, R.; van Dyk, D.; Connors, A.; Kashyap, V.; Siemiginowska, A.

    2000-12-01

    We examine the x-ray spectrum of the afterglow of GRB 970508, analyzed for Fe line emission by Piro et al (1999, ApJL, 514, L73). This is a difficult and extremely important measurement: the detection of x-ray afterglows from γ -ray bursts is at best a tricky business, relying on near-real satellite time response to unpredictable events; and a great deal of luck in catching a burst bright enough for a useful spectral analysis. Detecting a clear atomic (or cyclotron) line in the generally smooth and featureless afterglow (or burst) emission not only gives one of the few very specific keys to the physics local to the emission region, but also provides clues or confirmation of its distance (via redshift). Unfortunately, neither the likelihood ratio test or the related F-statistic commonly used to detect spectral lines adhere to their nominal Chi square and F-distributions. Thus we begin by calibrating the F-statistic used in Piro et al (1999, ApJL, 514, L73) via a simulation study. The simulation study relies on a completely specified source model, i.e. we do Monte Carlo simulations with all model parameters fixed (so--called ``parametric bootstrapping''). Second, we employ the method of posterior predictive p-values to calibrate a LRT statistic while accounting for the uncertainty in the parameters of the source model. Our analysis reveals evidence for the Fe K line.

  12. Clostridium XIV Meeting

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, Lee

    2016-08-28

    The 14th biannual Clostridium meeting was held at Dartmouth College from August 28 through 31, 2016. As noted in the meeting program (http://clostridiumxiv.com/wp-content/uploads/2016/09/Clostridium_XIV_program.pdf). the meeting featured 119 registered attendees, 33 oral presentations, 5 of which were given by younger presenters, 40 posters, and 2 keynote presentations, with strong participation by female and international scientists.

  13. Unresolved dielectronic satellites of the resonance line of heliumlike iron (Fe XXV)

    International Nuclear Information System (INIS)

    Bitter, M.; von Goeler, S.; Hill, K.W.; Horton, R.; Johnson, D.; Roney, W.; Sauthoff, N.; Silver, E.; Stodiek, W.

    1981-02-01

    (1s 2 nl - 1s2pnl, n greater than or equal to 3) dielectronic satellites of the resonance line of Fe XXV at 1.85 A have been observed from PLT (Princeton Large Torus) tokamak discharges and are used for a detailed comparison with theory. The necessary corrections for Doppler broadening measurements are discussed, and accurate satellite to resonance line ratios allowing for a determination of the total dielectronic recombination rate of Fe XXV are derived

  14. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae.

    Science.gov (United States)

    Keenan, F P; Aller, L H; Ryans, R S; Hyung, S

    2001-08-14

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d(6) levels of Fe III and among the 3d(2) levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures T(e) = 7,000-20,000 K and densities N(e) = 10(2)-10(8) cm(-3), whereas those for [Fe VII] are provided for T(e) = 10,000-30,000 K and N(e) = 10(2)-10(8) cm(-3). The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027.

  15. A comparison of theoretical and solar-flare intensity ratios for the Fe XIX X-ray lines

    International Nuclear Information System (INIS)

    Bhatia, A.K.; Mason, H.E.; Fawcett, B.C.; Phillips, K.J.H.

    1989-04-01

    Atomic data consisting of energy levels, g f-values and wavelengths are presented for the Fe XIX 2s 2 2p 4 -2s 2 2p 3 3s, 2s 2 2p 3 3d arrays that give rise to lines in solar flare and active-region X-ray spectra. Collision strengths and theoretical intensity ratios are given for the 2s 2 2p 4 -2s 2 2p 3 3d lines, which occur in the 13.2-14.3 A range. Solar spectra in this range include a large number of other intense lines, notably those due to He-like Ne (Ne IX). Although the Ne IX lines are potentially the most useful indicators of electron density in solar X-ray spectra, blending with the Fe XIX lines has been a major problem for previous analyses. Comparison of observed spectra with those calculated from the Fe XIX atomic data presented here and Ne IX lines from other work indicates that there is generally good agreement. We use the calculated Fe XIX and Ne IX line spectra and several observed spectra during a flare previously analysed to estimate electron density from Ne IX line ratios, thus for the first time properly taking into account blends with Fe XIX lines. (author)

  16. Solar Flare Termination Shock and Synthetic Emission Line Profiles of the Fe xxi 1354.08 Å Line

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Lijia [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA (United States); Li, Gang [Department of Space Science and CSPAR, University of Alabama in Huntsville, Huntsville, AL (United States); Reeves, Kathy; Raymond, John, E-mail: gang.li@uah.edu [Harvard-Smithsonian Center for Astrophysics, Boston, MA (United States)

    2017-09-01

    Solar flares are among the most energetic phenomena that occur in the solar system. In the standard solar flare model, a fast mode shock, often referred to as the flare termination shock (TS), can exist above the loop-top source of hard X-ray emissions. The existence of the TS has been recently related to spectral hardening of a flare’s hard X-ray spectra at energies >300 keV. Observations of the Fe xxi 1354.08 Å line during solar flares by the Interface Region Imaging Spectrograph ( IRIS ) spacecraft have found significant redshifts with >100 km s{sup −1}, which is consistent with a reconnection downflow. The ability to detect such a redshift with IRIS suggests that one may be able to use IRIS observations to identify flare TSs. Using a magnetohydrodynamic simulation to model magnetic reconnection of a solar flare and assuming the existence of a TS in the downflow of the reconnection plasma, we model the synthetic emission of the Fe xxi 1354.08 line in this work. We show that the existence of the TS in the solar flare may manifest itself in the Fe xxi 1354.08 Å line.

  17. ANALISIS KINERJA KEUANGAN PADA PT PERKEBUNAN NUSANTARA XIV MAKASSAR

    Directory of Open Access Journals (Sweden)

    Jefri Dominggus Simon

    2017-08-01

    Full Text Available JEFRI DOMINGGUS SIMON.2017. Thesis.4513012048. "Financial Performance Analysis at PT Perkebunan Nusantara XIV Makassar". (Mentored by Dr.Miah Said, SE., M.Si as consultant I and Muh.Kafrawi Yunus, SE., MM as consultant II. This study aims to analyze the financial performance of PT Perkebunan Nusantara XIV Makassar during 2013 until 2015 by using ratio analysis: Liquidity, solvency, Activity and Profitability. The results of this study indicate that based on Liquidity ratios including Current ratio, Quick ratio and Cash ratio has increased. In general, the ratio of Solvency is in a less good position, while for Profitability ratio of receivables turnover, inventory turnover and asset turnover fluctuated. In general, the activity ratio of PT Perkebunan Nusantara XIV Makassar in the period of 2013 to 2015 has decreased

  18. Hot rotating fp shell Fe isotopes near proton drip line

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2003-01-01

    F p shell 44-58 Fe nuclei have been investigated in highly excited state using the statistical theory of hot rotating nucleus. Effects of thermal and rotational excitation at drip line nuclei are studied

  19. X-ray line emission and plasma conditions in exploded Fe wires

    International Nuclear Information System (INIS)

    Burkhalter, P.G.; Dozier, C.M.; Stallings, C.; Cowan, R.D.

    1978-01-01

    Single-wire Fe spectra collected from two different exploded-wire generators (Gamble II and Owl II) were analyzed to determined the ionization stages produced in the plasmas. The temperature for the hot-plasma pinches for both generators was 1.4 +- 0.2 keV at which an abundance of Fe XXIV transitions is produced. The Fe K spectra from exploded wires are basically similar to those produced in the pinched plasma generated randomly in the vacuum spark; however, the exploded wires have lower plasma temperatures than the hottest pinches produced in the vacuum spark. A detailed interpretation of the Fe L spectra formed in the exploded wires permitted line and ionization stage identifications in the 7-12-A region. Such spectroscopic data is useful for analysis of complex Fe spectra generated in multitemperature plasma devices like Tokamaks

  20. Carbonate component reduces o,oEDDHA/Fe sorption on two-line ferrihydrite

    Science.gov (United States)

    Yunta, F.; Lucena, J. J.; Smolders, E.

    2012-04-01

    The o,oEDDHA/Fe is the most common and effective iron chelate used as fertilizer in calcareous soils. Several authors have reported that the anionic o,oEDDHA/Fe complex is adsorbed to soil components such as ferrihydrite. The bicarbonate anion may be a competing ion for this sorption, however no studies have yet identified the extent and mechanism of this interaction. The aim of this work was to study the carbonate (bicarbonate + carbonate) effect on EDDHA/Fe adsorption on two-line ferrihydrite. Two-line ferrihydrite was synthetized adding NaOH on a nitrate iron (III) solution up to a final pH to be 8.0 and allowing to age for 22 hours at 20°C. Dialyzed ferrihydrite was characterized by determining specific parameters such as Fe/OH ratio, BET surface, point zero of charge and x-ray diffraction. The sorption was performed at three pH levels (5, 7.5 and 9.5) and three initial carbonate concentrations (from 0 to 2 mM). Initial EDDHA/Fe, ferrihydrite and ionic strength concentrations were adjusted to 0.18 mM, 10 g L-1 and 5 mM respectively. Total dissolved FeEDDHA concentrations were quantified at 480 nm. The o,oEDDHA/Fe isomers (rac-o,oEDDHA/Fe and meso-o,oEDDHA/Fe) were separated and quantified by High Performance Liquid Chromatography (HPLC) fitting a photodiode array detector (PDA). Distribution factor (KD) and sorbed o,oEDDHA/Fe concentration were determined. Actual carbonate concentration was determined using a multi N/C analyzer. Ferrihydrite samples showed a typical XRD pattern of two-line ferrihydrite, two broad peaks at about 35 and 62° respectively. The BET surfaces (two replicates) were 259.2 ± 3.1 m2/g and 256.0 ± 2.5 m2/g. The Point Zero of Salt Effect (PZSE) was 7.9 ± 0.2 as bibliographically supported for all fresh and thus not rigorously de-carbonated ferrihydrite samples. The KD of the o,oEDDHA/Fe increased from 27.4 ± 0.6 to 304 ± 6 l/kg by decreasing pH from 9.5 and 5.0 when no carbonate was added. Increasing equilibrium carbonate

  1. 4p-5s transitions in In XIII, In XIV and In XV

    International Nuclear Information System (INIS)

    Carroll, P.K.; Costello, J.T.; O'Sullivan, G.

    1986-01-01

    The spectrum of an indium plasma produced by a 1.5 J, 25 ns ruby laser was recorded in the XUV. At wavelengths below 100 A, the spectrum is dominated by 4p-5s transitions in a number of ion stages. Many lines arising from 4p 6 4d-4p 5 4d5s, 4p 6 -4p 5 5s and 4p 5 -4p 4 5s transitions in In XIII, In XIV and In XV have been identified by isoelectronic extrapolation and Dirac-Fock calculations. (orig.)

  2. THE CORES OF THE FeLINES IN ACTIVE GALACTIC NUCLEI: AN EXTENDED CHANDRA HIGH ENERGY GRATING SAMPLE

    International Nuclear Information System (INIS)

    Shu, X. W.; Wang, J. X.; Yaqoob, T.

    2010-01-01

    We extend the study of the core of the Fe Kα emission line at ∼6.4 keV in Seyfert galaxies reported by Yaqoob and Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z H 23 cm -2 ) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Feline centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Feline is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources (∼94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 ± 3 eV. The mean FWHM from the subsample of 27 sources was 2060 ± 230 km s -1 . The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the Hβ optical emission-line widths (or, for one source, Brα), we find that there is no universal location of the Feline-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Feline flux from parsec-scale distances from the putative black hole, down to matter a factor ∼2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Feline EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Feline.

  3. Discrepancies between calculated and observed Fe XVII and Ni XIX solar coronal lines

    Energy Technology Data Exchange (ETDEWEB)

    Loulergue, M [Observatoire de Paris, Section de Meudon, 92 (France); Nussbaumer, H [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1975-12-01

    The 36-levels model atom Fe/sup +16/ of Loulergue and Nussbaumer (1973) is extended to a 51-levels atom including n=4 configuration. The earlier conclusion that relative intensities among the Fe XVII lines are not sufficiently sensitive to variations in electron densities and electron temperature to deduce these parameters from observed intensity ratios still holds. Discrepancies between calculated and observed relative intensities in Fe XVII and Ni XIX are attributed to blends or misidentifications.

  4. Chromospheric Evaporation in an M1.8 Flare Observed by the Extreme-ultraviolet Imaging Spectrometer (EIS) on Hinode

    Science.gov (United States)

    Doschek, G. A.; Warren, H. P.

    2012-12-01

    We discuss observations of chromospheric evaporation for a flare that occurred on 9 March 2012 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit reached almost the exact location of a significant energy input. Also, fortunately EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km/s upflows was observed in several locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, Fe XXIV, with simultaneous 20 - 60 km/s upflows in a host of million degree coronal lines from ions such as Fe XI - Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex. At a point close to strong energy input, the flare ions reveal an isothermal source with a temperature close to 14 MK. At this point there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. The results to be presented are refined from the preliminary data given above and combined with context AIA observations for a comparison with predictions of models of chromospheric evaporation as envisaged in the Standard Flare Model.

  5. Stellar and Laboratory XUV/EUV Line Ratios in Fe XVIII and Fe XIX

    Science.gov (United States)

    Träbert, Elmar; Beiersdorfer, P.; Clementson, J.

    2011-09-01

    A so-called XUV excess has been suspected with the relative fluxes of Fe XVIII and Fe XIX lines in XUV and EUV spectra of the star Capella as observed by the Chandra spacecraft [1] when comparing the observations with simulations of stellar spectra based on APEC or FAC. We have addressed this problem by laboratory studies using the Livermore electron beam ion trap (EBIT). Our understanding of the EBIT spectrum is founded on work by Brown et al. [2]. The electron density of the electron beam in an EBIT is compatible to the density in energetic stellar flares. In our experiments, the relative detection efficiencies of two flat-field grating spectrographs operating in the EUV (near 100 Å) and XUV (near 16 Å) ranges have been determined using the calculated branching ratio of 1-3 and 2-3 transition in the H-like spectrum O VIII. FAC calculations assuming several electron beam energies and electron densities serve to correct the EBIT observations for the Maxwellian excitation in a natural plasma. In the EUV, the line intensity pattern predicted by FAC agrees reasonably well with the laboratory and Capella observations. In the XUV wavelength range, agreement of laboratory and astrophysical line intensities is patchy. The spectral simulation results from FAC are much closer to stellar and laboratory observation than those obtained by APEC. Instead of claiming an XUV excess, the XUV/EUV line intensities can be explained by a somewhat higher temperature of Capella than the previously assumed T=6 MK. This work was performed under the auspices of the USDoE by LLNL under Contract DE-AC52-07NA27344 and was supported by the NASA under work order NNH07AF81I issued by the APRA Program. E.T. acknowledges support by DFG Germany. 1. P. Desai et al., ApJ 625, L59 (2005). 2. G. V. Brown et al., ApJS 140, 589 (2002).

  6. X-ray imaging of the Cr and Fe lines from Cassiopeia A

    NARCIS (Netherlands)

    Maeda, Y.; Sato, T.; Tsunemi, H.; Bamba, A.; Vink, J.; Terada, Y.; Takeda, T.; Sawada, M.; Gandhi, P.; Matsumoto, H.; Uchiyama, Y.; Helder, E.A.; Hiraga, J.; Hughes, J.P.; Kokubun, M.; Tamagawa, T.; Tsuboi, Y.; Ishida, M.; Petre, R.; Mitsuda, K.

    2014-01-01

    Follow-up Suzaku X-ray observations of a young supernova remnant Cassiopeia A carried out with a long exposure of ˜ 165 ksec in 2012. Owing to the high statistics of the data, the map of Cr-K line is made. The flux map of Cr-K line is similar to that of Fe-K. The similarity indicates that the

  7. Laboratory measurements of the x-ray line emission from neon-like Fe XVII

    International Nuclear Information System (INIS)

    Brown, G V; Beiersdorfer, P; Chen, H; Scofield, J; Boyce, K R; Kelley, R L; Kilbourne, C A; Porter, F S; Gu, M F; Kahn, S M; Szymkowiak, A E

    2006-01-01

    The authors have conducted a systematic study of the dominant x-ray line emission from Fe XVII. These studies include relative line intensities in the optically thin limit, intensities in the presence of radiation from satellite lines from lower charge states of iron, and the absolute excitation cross sections of some of the strongest lines. These measurements were conducted at the Lawrence Livermore National Laboratory electron beam ion trap facility using crystal spectrometers and a NASA-Goddard Space Flight Center microcalorimeter array

  8. Observed magnetic dipole transitions in the ground terms of Ti XIV, Ti XV, and Ti XVII

    International Nuclear Information System (INIS)

    Suckewer, S.; Fonck, R.; Hinnov, E.

    1979-09-01

    Four observed spectrum lines in titanium-containing tokamak discharges have been identified as follows: TiXIV 2s 2 2p 5 2 P/sub 1/2/ → 2 P/sub 3/2/ at 2115.3 A, TiXV 2s 2 2p 4 3P 1 → 3 P 2 at 2544.8 A, TiXVII 2s 2 2p 2 3 P 2 → 3 P 1 at 3834.4 A and 3 P 1 → 3 P 0 at 3371.5 A. The identifications are based on observed time behavior and correlation with intensities of resonance lines of other titanium ions, and on general agreement with predicted wavelengths and intensities

  9. Type XII and XIV collagens mediate interactions between banded collagen fibers in vitro and may modulate extracellular matrix deformability.

    Science.gov (United States)

    Nishiyama, T; McDonough, A M; Bruns, R R; Burgeson, R E

    1994-11-11

    Type XII and XIV collagens are very large molecules containing three extended globular domains derived from the amino terminus of each alpha chain and an interrupted triple helix. Both collagens are genetically and immunologically unique and have distinct distributions in many tissues. These collagens localize near the surface of banded collagen fibrils. The function of the molecules is unknown. We have prepared a mixture of native type XII and XIV collagens that is free of contaminating proteins by electrophoretic criteria. In addition, we have purified the collagenase-resistant globular domains of type XII or XIV collagens (XII-NC-3 or XIV-NC-3). In this study, we have investigated the effect of intact type XII and XIV and XII-NC-3 or XIV-NC-3 on the interactions between fibroblasts and type I collagen fibrils. We find that both type XII and XIV collagens promote collagen gel contraction mediated by fibroblasts, even in the absence of serum. The activity is present in the NC-3 domains. The effect is dose-dependent and is inhibited by denaturation. The effect of type XII NC-3 is inhibited by the addition of anti-XII antiserum. To elucidate the mechanism underlying this phenomenon, we examined the effect of XII-NC-3 or XIV-NC-3 on deformability of collagen gels by centrifugal force. XII-NC-3 or XIV-NC-3 markedly promotes gel compression after centrifugation. The effect is also inhibited by denaturation, and the activity of type XII-NC3 is inhibited by the addition of anti-XII antiserum. The results indicate that the effect of XII-NC-3 or XIV-NC-3 on collagen gel contraction by fibroblasts is not due to activation of cellular events but rather results from the increase in mobility of hydrated collagen fibrils within the gel. These studies suggest that collagen types XII and XIV may modulate the biomechanical properties of tissues.

  10. Transformation lines in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy

    International Nuclear Information System (INIS)

    Tanaka, Kikuaki; Hayashi, Toshimitsu; Fischer, F.D.; Buchmayr, B.

    1994-01-01

    Transformation lines, the martensite/austenite start and finish conditions in the stress-temperature plane, are determined in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy with two different experimental procedures. The transformation lines are shown to be almost linear with nearly the same slope. The martensitic transformation zone and the reverse transformation zone do not coincide, and the reverse transformation zone is very wide; T Af -T As ∼ 180 K. The strong dependence on the preloading of the transformation lines, especially of the reverse transformation lines, is examined. (orig.)

  11. QUASI-PERIODIC FLUCTUATIONS AND CHROMOSPHERIC EVAPORATION IN A SOLAR FLARE RIBBON OBSERVED BY HINODE /EIS, IRIS , AND RHESSI

    Energy Technology Data Exchange (ETDEWEB)

    Brosius, Jeffrey W.; Inglis, Andrew R. [Catholic University of America at NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States); Daw, Adrian N., E-mail: Jeffrey.W.Brosius@nasa.gov [NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States)

    2016-10-20

    The Hinode /Extreme-ultraviolet Imaging Spectrometer (EIS) obtained rapid cadence (11.2 s) EUV stare spectra of an M7.3 flare ribbon in AR 12036 on 2014 April 18. Quasi-periodic ( P ≈ 75.6 ± 9.2 s) intensity fluctuations occurred in emission lines of O iv, Mg vi, Mg vii, Si vii, Fe xiv, and Fe xvi during the flare's impulsive rise, and ended when the maximum intensity in Fe xxiii was reached. The profiles of the O iv–Fe xvi lines reveal that they were all redshifted during most of the interval of quasi-periodic intensity fluctuations, while the Fe xxiii profile revealed multiple components including one or two highly blueshifted ones. This indicates that the flare underwent explosive chromospheric evaporation during its impulsive rise. Fluctuations in the relative Doppler velocities were seen, but their amplitudes were too subtle to extract significant quasi-periodicities. RHESSI detected 25–100 keV hard-X-ray sources in the ribbon near the EIS slit's pointing position during the peaks in the EIS intensity fluctuations. The observations are consistent with a series of energy injections into the chromosphere by nonthermal particle beams. Electron densities derived with Fe xiv (4.6 × 10{sup 10} cm{sup −3}) and Mg vii (7.8 × 10{sup 9} cm{sup −3}) average line intensity ratios during the interval of quasi-periodic intensity fluctuations, combined with the radiative loss function of an optically thin plasma, yield radiative cooling times of 32 s at 2.0 × 10{sup 6} K, and 46 s at 6.3 × 10{sup 5} K (about half the quasi-period); assuming Fe xiv's density for Fe xxiii yields a radiative cooling time of 10{sup 3} s (13 times the quasi-period) at 1.4 × 10{sup 7} K.

  12. ASPIICS: a giant, white light and emission line coronagraph for the ESA proba-3 formation flight mission

    Science.gov (United States)

    Lamy, P. L.; Vivès, S.; Curdt, W.; Damé, L.; Davila, J.; Defise, J.-M.; Fineschi, S.; Heinzel, P.; Howard, Russel; Kuzin, S.; Schmutz, W.; Tsinganos, K.; Zhukov, A.

    2017-11-01

    Classical externally-occulted coronagraphs are presently limited in their performances by the distance between the external occulter and the front objective. The diffraction fringe from the occulter and the vignetted pupil which degrades the spatial resolution prevent useful observations of the white light corona inside typically 2-2.5 solar radii (Rsun). Formation flying offers and elegant solution to these limitations and allows conceiving giant, externally-occulted coronagraphs using a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at a distance of hundred meters [1, 2]. Such an instrument ASPIICS (Association de Satellites Pour l'Imagerie et l'Interférométrie de la Couronne Solaire) has been selected by the European Space Agency (ESA) to fly on its PROBA-3 mission of formation flying demonstration which is presently in phase B (Fig. 1). The classical design of an externally-occulted coronagraph is adapted to the formation flying configuration allowing the detection of the very inner corona as close as 0.04 solar radii from the solar limb. By tuning the position of the occulter spacecraft, it may even be possible to reach the chromosphere and the upper part of the spicules [3]. ASPIICS will perform (i) high spatial resolution imaging of the continuum K+F corona in photometric and polarimetric modes, (ii) high spatial resolution imaging of the E-corona in two coronal emission lines (CEL): Fe XIV and He I D3, and (iii) two-dimensional spectrophotometry of the Fe XIV emission line. ASPIICS will address the question of the coronal heating and the role of waves by characterizing propagating fluctuations (waves and turbulence) in the solar wind acceleration region and by looking for oscillations in the intensity and Doppler shift of spectral lines. The combined imaging and spectral diagnostics capabilities available with ASPIICS will allow mapping the velocity field of the corona both in the

  13. Evidence of Decay of Flux Ratio of Fe to Fe–Ni Line Features with ...

    Indian Academy of Sciences (India)

    2010-08-18

    Aug 18, 2010 ... measuring of the intensity and mean energy of the Fe and Fe–Ni line ... The instrumentation of the SLD payload, its in-flight calibration and operation ... reconnection process and also decays faster compared to many other ... measure vary over time and these factors mainly control the shape of the line. The.

  14. 25 CFR 36.41 - Standard XIV-Textbooks.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Standard XIV-Textbooks. 36.41 Section 36.41 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional Support § 36.41 Standard XIV—Textbooks. (a) Each school shal...

  15. UV and X-ray spectral lines of Be-like Fe ion for plasma diagnostics

    International Nuclear Information System (INIS)

    Murakami, Izumi; Kato, Takako; Dubau, J.

    1996-04-01

    We have calculated X-ray and UV spectra of the Be-like Fe (FeXXIII) ion using collisional-radiative model including all fine-structure transitions among the 2s 2 , 2s2p, 2p 2 , 2snl, and 2pnl levels where n = 3 and 4, adopting data for the collision strengths by Zhang and Sampson (1992) and by Sampson, Goett, and Clark (1984). Some line intensity ratios can be used for the temperature diagnostic. We show 5 ratios in UV region and 9 ratios in X-ray region as functions of electron temperature and density at 0.3keV e e = 1-10 25 cm -3 . The effect of cascade in these line ratios is discussed. (author)

  16. New Fe i Level Energies and Line Identifications from Stellar Spectra. II. Initial Results from New Ultraviolet Spectra of Metal-poor Stars

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Ruth C. [SETI Institute and Astrophysical Advances, 607 Marion Place, Palo Alto, CA 94301 (United States); Kurucz, Robert L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ayres, Thomas R., E-mail: peterson@ucolick.org [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-0389 (United States)

    2017-04-01

    The Fe i spectrum is critical to many areas of astrophysics, yet many of the high-lying levels remain uncharacterized. To remedy this deficiency, Peterson and Kurucz identified Fe i lines in archival ultraviolet and optical spectra of metal-poor stars, whose warm temperatures favor moderate Fe i excitation. Sixty-five new levels were recovered, with 1500 detectable lines, including several bound levels in the ionization continuum of Fe i. Here, we extend the previous work by identifying 59 additional levels, with 1400 detectable lines, by incorporating new high-resolution UV spectra of warm metal-poor stars recently obtained by the Hubble Space Telescope Imaging Spectrograph. We provide gf values for these transitions, both computed as well as adjusted to fit the stellar spectra. We also expand our spectral calculations to the infrared, confirming three levels by matching high-quality spectra of the Sun and two cool stars in the H -band. The predicted gf values suggest that an additional 3700 Fe i lines should be detectable in existing solar infrared spectra. Extending the empirical line identification work to the infrared would help confirm additional Fe i levels, as would new high-resolution UV spectra of metal-poor turnoff stars below 1900 Å.

  17. Prototype ATLAS IBL modules using the FE-I4A front-end readout chip

    Czech Academy of Sciences Publication Activity Database

    Albert, J.; Alex, M.; Alimonti, G.; Hejtmánek, Martin; Janoška, Zdenko; Korchak, Oleksandr; Popule, Jiří; Šícho, Petr; Sloboda, Michal; Tomášek, Michal; Vrba, Václav

    2012-01-01

    Roč. 7, NOV (2012), 1-45 ISSN 1748-0221 R&D Projects: GA MŠk LA08032 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * upgrade * tracker * silicon * FE-I4 * planar sensors * test beam Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.869, year: 2011 http://arxiv.org/abs/arXiv:1209.1906

  18. CHROMOSPHERIC EVAPORATION IN AN M1.8 FLARE OBSERVED BY THE EXTREME-ULTRAVIOLET IMAGING SPECTROMETER ON HINODE

    International Nuclear Information System (INIS)

    Doschek, G. A.; Warren, H. P.; Young, P. R.

    2013-01-01

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s –1 upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s –1 upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s –1 . We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive

  19. Chromospheric Evaporation in an M1.8 Flare Observed by the Extreme-ultraviolet Imaging Spectrometer on Hinode

    Science.gov (United States)

    Doschek, G. A.; Warren, H. P.; Young, P. R.

    2013-04-01

    We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s-1 upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s-1 upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s-1. We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive tests of

  20. Exploration report in mining reserve XIV

    International Nuclear Information System (INIS)

    Spoturno Pioppo, J.; Lara Vigil, P.

    1991-01-01

    This report has been referred to the antecedents and works developed in the mining Reservation XIV. This Reservation, covered a 1900 km2 surface, involving the aerial photography Valentines Cerro Chato, Chileno, Rossel y Rius, Sarandi del Yi and Cuchilla del Pescado. It has been reduced this area to western part of the aerial phothograpy Pavas, releasing other areas such as Chileno, Rossel y Rius, Cuchilla del Pescado y Cerro Chato. Finally, gold, sulphures, pirite and carbonates iron oxides findings have been found.

  1. Fe-Cluster Compounds of Chalcogenides: Candidates for Rare-Earth-Free Permanent Magnet and Magnetic Nodal-Line Topological Material.

    Science.gov (United States)

    Zhao, Xin; Wang, Cai-Zhuang; Kim, Minsung; Ho, Kai-Ming

    2017-12-04

    Fe-cluster-based crystal structures are predicted for chalcogenides Fe 3 X 4 (X = S, Se, Te) using an adaptive genetic algorithm. Topologically different from the well-studied layered structures of iron chalcogenides, the newly predicted structures consist of Fe clusters that are either separated by the chalcogen atoms or connected via sharing of the vertex Fe atoms. Using first-principles calculations, we demonstrate that these structures have competitive or even lower formation energies than the experimentally synthesized Fe 3 X 4 compounds and exhibit interesting magnetic and electronic properties. In particular, we show that Fe 3 Te 4 can be a good candidate as a rare-earth-free permanent magnet and Fe 3 S 4 can be a magnetic nodal-line topological material.

  2. The response of the Fe K\\alpha line to changes in the X-ray illumination of accretion discs

    OpenAIRE

    Ballantyne, D. R.; Ross, R. R.

    2002-01-01

    X-ray reflection spectra from photoionized accretion discs in active galaxies are presented for a wide range of illumination conditions. The energy, equivalent width (EW) and flux of the Fe K line are shown to depend strongly on the ratio of illuminating flux to disc flux, Fx/Fdisc, the photon index of the irradiating power-law, \\Gamma, and the incidence angle of the radiation, i. When Fx/Fdisc \\leq 2 a neutral Fe K line is prominent for all but the largest values of \\Gamma. At higher illumin...

  3. A TEST OF THE NATURE OF THE FE K LINE IN THE NEUTRON STAR LOW-MASS X-RAY BINARY SERPENS X-1

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chia-Ying; Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock, Detroit, MI 48202 (United States); Miller, Jon M. [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI48109-1046 (United States); Barret, Didier [Universite de Toulouse, UPS-OMP, Toulouse (France); Fabian, Andy C.; Parker, Michael L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); D’Aì, Antonino [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, via U. La Malfa 153, I-90146 Palermo (Italy); Bhattacharyya, Sudip [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Burderi, Luciano [Dipartimento di Fisica, Università degli Studi di Cagliari, SP Monserrato-Sestu, KM 0.7, I-09042 Monserrato (Italy); Salvo, Tiziana Di; Iaria, Rosario [Dipartimento di Fisica e Chimica, Universitá di Palermo, via Archirafi 36, I-90123 Palermo (Italy); Egron, Elise [INAF-Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); Homan, Jeroen [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-582D, Cambridge, MA 02139 (United States); Lin, Dacheng [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Miller, M. Coleman, E-mail: ft8320@wayne.edu [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 (United States)

    2016-04-20

    Broad Fe K emission lines have been widely observed in the X-ray spectra of black hole systems as well as in neutron star systems. The intrinsically narrow Fe K fluorescent line is generally believed to be part of the reflection spectrum originating in an illuminated accretion disk which is broadened by strong relativistic effects. However, the nature of the lines in neutron star low-mass X-ray binaries (LMXBs) has been a matter of debate. We therefore obtained the longest, high-resolution X-ray spectrum of a neutron star LMXB to date with a 300 ks Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of Serpens X-1. The observation was taken under the “continuous clocking” mode, and thus was free of photon pile-up effects. We carry out a systematic analysis and find that the blurred reflection model fits the Fe line of Serpens X-1 significantly better than a broad Gaussian component does, implying that the relativistic reflection scenario is much preferred. Chandra HETGS also provides a highest spectral resolution view of the Fe K region and we find no strong evidence for additional narrow lines.

  4. Properties of Fe, Ni and Zn isotope chains near the drip-line

    International Nuclear Information System (INIS)

    Tarasov, V.N.; Tarasov, D.V.; Kuprikov, V.I.; Gridnev, K.A.; Gridnev, D.K.; Gridnev, K.A.; Gridnev, D.K.; Kartavenko, V.G.; Greiner, W.; Kartavenko, V.G.

    2007-01-01

    The location of proton and neutron drip-lines and the characteristics of the neutron-deficient and the neutron-rich isotopes Fe, Ni and Zn on the basis of Hartree-Fock method with Skyrme forces (Ska, SkM * , Sly4) taking into account deformation was investigated. The calculations predict a big jump of deformation parameter up to β ∼ 0.4 for Ni isotopes in the neighborhood of N ∼ 62. The manifestation of magic numbers for isotopes 48 Ni, 56 Ni, 78 Ni and also for the stable isotope in the respect to neutron emission 110 Ni which is situated beyond the neutron drip-line is discussed

  5. International Conference Approximation Theory XIV

    CERN Document Server

    Schumaker, Larry

    2014-01-01

    This volume developed from papers presented at the international conference Approximation Theory XIV,  held April 7–10, 2013 in San Antonio, Texas. The proceedings contains surveys by invited speakers, covering topics such as splines on non-tensor-product meshes, Wachspress and mean value coordinates, curvelets and shearlets, barycentric interpolation, and polynomial approximation on spheres and balls. Other contributed papers address a variety of current topics in approximation theory, including eigenvalue sequences of positive integral operators, image registration, and support vector machines. This book will be of interest to mathematicians, engineers, and computer scientists working in approximation theory, computer-aided geometric design, numerical analysis, and related approximation areas.

  6. Insights into Resistance to Fe Deficiency Stress from a Comparative Study of In Vitro-Selected Novel Fe-Efficient and Fe-Inefficient Potato Plants

    Directory of Open Access Journals (Sweden)

    Georgina A. Boamponsem

    2017-09-01

    Full Text Available Iron (Fe deficiency induces chlorosis (IDC in plants and can result in reduced plant productivity. Therefore, development of Fe-efficient plants is of great interest. To gain a better understanding of the physiology of Fe-efficient plants, putative novel plant variants were regenerated from potato (Solanum tubersosum L. var. ‘Iwa’ callus cultures selected under Fe deficient or low Fe supply (0–5 μM Fe. Based on visual chlorosis rating (VCR, 23% of callus-derived regenerants were classified as Fe-efficient (EF and 77% as Fe-inefficient (IFN plant lines when they were grown under Fe deficiency conditions. Stem height was found to be highly correlated with internodal distance, leaf and root lengths in the EF plant lines grown under Fe deficiency conditions. In addition, compared to the IFN plant lines and control parental biotype, the EF plants including the lines named A1, B2, and B9, exhibited enhanced formation of lateral roots and root hairs as well as increased expression of ferritin (fer3 in the leaf and iron-regulated transporter (irt1 in the root. These morphological adaptations and changes in expression the fer3 and irt1 genes of the selected EF potato lines suggest that they are associated with resistance to low Fe supply stress.

  7. Fe-K LINE PROBING OF MATERIAL AROUND THE ACTIVE GALACTIC NUCLEUS CENTRAL ENGINE WITH SUZAKU

    International Nuclear Information System (INIS)

    Fukazawa, Yasushi; Hiragi, Kazuyoshi; Mizuno, Motohiro; Nishino, Sho; Hayashi, Katsuhiro; Yamasaki, Tomonori; Shirai, Hirohisa; Takahashi, Hiromitsu; Ohno, Masanori

    2011-01-01

    We systematically analyzed the high-quality Suzaku data of 88 Seyfert galaxies, about 31% of which are Compton-thick active galactic nuclei (AGNs). We obtained a clear relation between the absorption column density and the equivalent width (EW) of the 6.4 keV line above 10 23 cm -2 , suggesting a wide-ranging column density of 10 23 -10 24.5 cm -2 with a similar solid and an Fe abundance of 0.7-1.3 solar for Seyfert 2 galaxies. The EWs of the 6.4 keV line for Seyfert 1 galaxies are typically 40-120 eV, suggesting the existence of Compton-thick matter like the torus with a column density of >10 23 cm -2 and a solid angle of (0.15-0.4) x 4π, and no difference of neutral matter is visible between Seyfert 1 and 2 galaxies. An absorber with a lower column density of 10 21 -10 23 cm -2 for Compton-thin Seyfert 2 galaxies is suggested to be not a torus but an interstellar medium. These constraints can be understood by the fact that the 6.4 keV line intensity ratio against the 10-50 keV flux is almost identical within a range of 2-3 in many Seyfert galaxies. Interestingly, objects exist with a low EW, 10-30 eV, of the 6.4 keV line, suggesting that those torus subtends only a small solid angle of H >10 23 cm -2 indicates that the column density of the ionized material also increases together with that of the cold material. It is found that these features seem to change for brighter objects with more than several 10 44 erg s -1 such that the Fe-K line features become weak. This extends the previously known X-ray Baldwin effect on the neutral Fe-Kα line to ionized emission or absorption lines. The luminosity dependence of these properties, regardless of the scatter of black hole mass by two orders of magnitudes, indicates that the ionized material is associated with the structure of the parent galaxy rather than the outflow from the nucleus.

  8. Coronal emission-line polarization from the statistical equilibrium of magnetic sublevels. I. Fe XII

    International Nuclear Information System (INIS)

    House, L.L.

    1977-01-01

    A general formulation for the polarization of coronal emission lines is presented, and the physics is illustrated through application of the formulation to the lines of Fe XIII at 10747 and 10798 A. The goal is to present a foundation for the determination of the orientation of coronal magnetic fields from emission-line polarization measurements. The physics of emission-line polarization is discussed using the statistical equilibrium equations for the magnetic sublevels of a coronal ion. The formulation of these equations, which describe the polarization of the radiation field in terms of Stokes parameters, is presented; and the various rate parameters: both radiative and collisional: are considered. The emission Stokes vector is constructed from the solution of the equilibrium equations for a point in the corona where the magnetic field has an arbitrary orientation. On the basis of a model, a computer code for the calculation of emission-line polarization is briefly described and illustrated with a number of sample calculations for Fe XIII. Calculations are carried out for three-dimensional models that demonstrate the physics of the formation of emission-line polarization and illustrate how the degree of polarization and angle of polarization and their variations over the corona are related to the density and magnetic field structure. The models considered range from simple cases in which the density distribution with height is spherically symmetric and the field is radial or dipole to a complex case in which both the density and magnetic field distributions are derived from realistic three-dimensional distributions for the 1973 eclipse on the basis of K-coronameter measurements for the density and potential-field extrapolation of surface magnetic fields in the corona

  9. Detection of broad ultraviolet Fe II lines in the spectrum of NGC 1068

    International Nuclear Information System (INIS)

    Snijders, M.A.J.; Netzer, Hagai; Boksenberg, A.

    1986-01-01

    Ultraviolet observations of the nucleus of NGC 1068, obtained by the IUE over a period of 5 yr, are combined to give a high signal-to-noise spectrum of this source. The ultraviolet stellar continuum, obtained by comparison with ground-based data, is subtracted to show the nuclear non-stellar component. The resulting spectrum shows clearly the presence of strong broad FeII emission bands similar to those observed in many broad-line objects. Broad profiles are also seen in other strong emission lines. These observations confirm the recent discovery of an optical Seyfert type 1 spectrum in NGC 1068. (author)

  10. Peculiar time dependence of unexpected lines in delayed beam-foil X-ray spectra of V, Fe and Ni

    International Nuclear Information System (INIS)

    Ahmad, Nissar; Karn, Ranjeet K.; Marketos, Pan; Nandi, T.

    2005-01-01

    Delayed beam-foil X-ray spectra of highly charged ions of V, Fe and Ni show a few lines at energies higher than the H-like Lyman α-line of the respective projectile ions. These can only be attributed to heavier ions. Further the time dependence of such unexpected lines display a peculiar behavior. This work presents the experimental observations systematically

  11. Observation and modelling of the Fe XXI line profile observed by IRIS during the impulsive phase of flares

    Science.gov (United States)

    Polito, V.; Testa, P.; De Pontieu, B.; Allred, J. C.

    2017-12-01

    The observation of the high temperature (above 10 MK) Fe XXI 1354.1 A line with the Interface Region Imaging Spectrograph (IRIS) has provided significant insights into the chromospheric evaporation process in flares. In particular, the line is often observed to be completely blueshifted, in contrast to previous observations at lower spatial and spectral resolution, and in agreement with predictions from theoretical models. Interestingly, the line is also observed to be mostly symmetric and with a large excess above the thermal width. One popular interpretation for the excess broadening is given by assuming a superposition of flows from different loop strands. In this work, we perform a statistical analysis of Fe XXI line profiles observed by IRIS during the impulsive phase of flares and compare our results with hydrodynamic simulations of multi-thread flare loops performed with the 1D RADYN code. Our results indicate that the multi-thread models cannot easily reproduce the symmetry of the line and that some other physical process might need to be invoked in order to explain the observed profiles.

  12. Detailed single-crystal EPR line shape measurements for the single-molecule magnets Fe8Br and Mn12-acetate

    Science.gov (United States)

    Hill, S.; Maccagnano, S.; Park, Kyungwha; Achey, R. M.; North, J. M.; Dalal, N. S.

    2002-06-01

    It is shown that our multi-high-frequency (40-200 GHz) resonant cavity technique yields distortion-free high-field electron paramagnetic resonance (EPR) spectra for single-crystal samples of the uniaxial and biaxial spin S=10 single-molecule magnets (SMM's) [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O and [Fe8O2(OH)12(tacn)6]Br8.9H2O. The observed line shapes exhibit a pronounced dependence on temperature, magnetic field, and the spin quantum numbers (MS values) associated with the levels involved in the transitions. Measurements at many frequencies allow us to separate various contributions to the EPR linewidths, including significant D strain, g strain, and broadening due to the random dipolar fields of neighboring molecules. We also identify asymmetry in some of the EPR line shapes for Fe8 and a previously unobserved fine structure to some of the EPR lines for both the Fe8 and Mn12 systems. These findings prove relevant to the mechanism of quantum tunneling of magnetization in these SMM's.

  13. The Beam Line X NdFe-steel hybrid wiggler for SSRL

    International Nuclear Information System (INIS)

    Hoyer, E.; Halbach, K.; Humphries, D.; Marks, S.; Plate, D.; Shuman, D.; Karpenko, V.P.; Kulkarni, S.; Tirsell, K.G.

    1987-01-01

    A wiggler magnet with 15 periods, each 12.85 cm long, which achieves 1.40 T at a 2.1 cm gap (2.26T at 0.8 cm) has been designed and is now in fabrication at LBL. This wiggler will be the radiation source of the high intensity synchrotron radiation beam line for the Beam Line X PRT facility at SSRL. The magnet utilizes Neodymium-Iron (NdFe) material and Vanadium Permendur (steel) in the hybrid configuration to achieve simultaneously a high magnetic field and short period. Magnetic field adjustment is with a driven chain and ball screw drive system. The magnetic structure is external to an s.s. vacuum chamber which has thin walls, 0.76 mm thickness, at each pole tip for higher field operation. Magnetic design, construction details and magnetic measurements are presented

  14. Atomic data and spectral line intensities for Fe XVII

    International Nuclear Information System (INIS)

    Bhatia, A.K.; Doschek, G.A.

    2003-01-01

    Electron impact collision strengths and spontaneous radiative decay rates are calculated for Fe XVII. The data pertain to the 73 levels of the configurations, 2s 2 2p 6 , 2s 2 2p 5 3s, 2s 2 2p 5 3p 2s 2 2p 5 3d, 2s2p 6 3s, 2s2p 6 3p, 2s2p 6 3d, 2s 2 2p 5 4s, 2s 2 2p 5 4p, 2s 2 2p 5 4d, 2s2p 6 4s, 2s2p 6 4p, and 2s2p 6 4d. Collision strengths are calculated at 11 incident electron energies: 58.5, 65.0, 70.0, 76.0, 85.0, 127.5, 170.0, 212.5, 255.0, 340.0, and 425.0 Ry. This work is an improvement over our earlier work on Fe XVII in two respects: (1) configurations involving 4s, 4p, and 4d electrons have been added and (2) a broader range of incident electron energies is used in the computation of collision strengths and excitation rate coefficients. Relative spectral line intensities are calculated for astrophysically important transitions. These are obtained by computing the excitation rate coefficients (cm 3 s -1 ), i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 73 energy levels, assuming a collisional excitation model and an electron temperature of 4 x 10 6 K. This temperature is typical for Fe XVII when formed in equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for five electron densities and are given in this paper

  15. RF and microwave noise suppression in a transmission line using Fe-Si-Al/Ni-Zn magnetic composite films

    International Nuclear Information System (INIS)

    Lee, J. W.; Hong, Y. K.; Kim, K.; Joo, J.; Yoon, Y. W.; Kim, S. W.; Kim, Y. B.; Kim, K. Y.

    2006-01-01

    Radio-frequency (RF) and microwave noise suppression by using magnetic composite films on a microstrip line (MSL) was studied in the frequency range from 50 MHz to 13.5 GHz. The MSL was composed of a Cu transmission line, dielectric materials, and a Cu substrate. The Fe-Si-Al/Ni-Zn magnetic composite films were placed on the MSL, and the reflection and the transmission characteristics were investigated. We observed that RF and microwave noise suppression caused by the Fe-Si-Al/Ni-Zn magnetic composite films varied with the concentration ratio of the sendust (Fe-Si-Al) and the Ni-Zn ferrite. The frequency dependence of the power loss due to the composite films on the MSL was measured and the power loss increased at higher frequencies with increasing concentration of the sendust in the composites. The electromagnetic interference shielding efficiencies of the magnetic composite films in the far-field region are also discussed.

  16. Poliitika ja poeesia eesti graafikas : Tallinna XIV graafikatriennaal ja "Impact 5" / Andri Ksenofontov

    Index Scriptorium Estoniae

    Ksenofontov, Andri, 1962-

    2007-01-01

    Tallinna XIV graafikatriennaalist "Poliitiline/Poeetiline" ning rahvusvahelisest graafikakonverentsist "Impact 5" teemal "Lõigatud aeg" ja selle raames avatud näitustest (Vappu Thurlowi kureeritud "Lõigatud aeg" Adamson-Ericu muuseumis jpt.)

  17. Establishment of a novel feline leukemia virus (FeLV)-negative B-cell cell line from a cat with B-cell lymphoma.

    Science.gov (United States)

    Mochizuki, Hiroyuki; Takahashi, Masashi; Nishigaki, Kazuo; Ide, Tetsuya; Goto-Koshino, Yuko; Watanabe, Shinya; Sato, Hirofumi; Sato, Masahiko; Kotera, Yukiko; Fujino, Yasuhito; Ohno, Koichi; Uchida, Kazuyuki; Tsujimoto, Hajime

    2011-04-15

    We established a novel feline B-cell line, MS4, from the neoplastic pleural effusion of a cat with cutaneous B-cell lymphoma. Immunophenotype staining of the MS4 cells was positive for CD20, CD79α, and IgA and negative for CD3, CD4, CD5, CD8α, CD18, CD21, CD22, IgM, IgG, Ig light chain, and MHC class II. PCR analysis for immunoglobulin heavy chain gene rearrangements revealed a monoclonal rearrangement, whereas no clonal rearrangement of the T-cell receptor γ gene was detected. Southern blotting with an exogenous feline leukemia virus (FeLV) U3 probe revealed no integration of exogenous FeLV provirus. The MS4 cell line is the first FeLV-negative feline B-cell lymphoma cell line, and may be used to investigate the pathogenesis of spontaneously occurring feline lymphoma and the development of new therapies. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Optical design of visible emission line coronagraph on Indian space solar mission Aditya-L1

    Science.gov (United States)

    Raj Kumar, N.; Raghavendra Prasad, B.; Singh, Jagdev; Venkata, Suresh

    2018-03-01

    The ground based observations of the coronal emission lines using a coronagraph are affected by the short duration of clear sky and varying sky transparency. These conditions do not permit to study small amplitude variations in the coronal emission reliably necessary to investigate the process or processes involved in heating the coronal plasma and dynamics of solar corona. The proposed Visible Emission Line Coronagraph (VELC) over comes these limitations and will provide continuous observation 24 h a day needed for detailed studies of solar corona and drivers for space weather predictions. VELC payload onboard India's Aditya-L1 space mission is an internally occulted solar coronagraph for studying the temperature, velocity, density and heating of solar corona. To achieve the proposed science goals, an instrument which is capable of carrying out simultaneous imaging, spectroscopy and spectro-polarimetric observations of the solar corona close to the solar limb is required. VELC is designed with salient features of (a) Imaging solar corona at 500 nm with an angular resolution of 5 arcsec over a FOV of 1.05Ro to 3Ro (Ro:Solar radius) (b) Simultaneous multi-slit spectroscopy at 530.3 nm [Fe XIV],789.2 nm [Fe XI] and 1074.7 nm [Fe XIII] with spectral dispersion of 28mÅ, 31mÅ and 202mÅ per pixel respectively, over a FOV of 1.05Ro to 1.5Ro. (c) Multi-slit dual beam spectro-polarimetry at 1074.7 nm. All the components of instrument have been optimized in view of the scientific objectives and requirements of space payloads. In this paper we present the details of optical configuration and the expected performance of the payload.

  19. Optical design of visible emission line coronagraph on Indian space solar mission Aditya-L1

    Science.gov (United States)

    Raj Kumar, N.; Raghavendra Prasad, B.; Singh, Jagdev; Venkata, Suresh

    2018-04-01

    The ground based observations of the coronal emission lines using a coronagraph are affected by the short duration of clear sky and varying sky transparency. These conditions do not permit to study small amplitude variations in the coronal emission reliably necessary to investigate the process or processes involved in heating the coronal plasma and dynamics of solar corona. The proposed Visible Emission Line Coronagraph (VELC) over comes these limitations and will provide continuous observation 24 h a day needed for detailed studies of solar corona and drivers for space weather predictions. VELC payload onboard India's Aditya-L1 space mission is an internally occulted solar coronagraph for studying the temperature, velocity, density and heating of solar corona. To achieve the proposed science goals, an instrument which is capable of carrying out simultaneous imaging, spectroscopy and spectro-polarimetric observations of the solar corona close to the solar limb is required. VELC is designed with salient features of (a) Imaging solar corona at 500 nm with an angular resolution of 5 arcsec over a FOV of 1.05Ro to 3Ro (Ro:Solar radius) (b) Simultaneous multi-slit spectroscopy at 530.3 nm [Fe XIV],789.2 nm [Fe XI] and 1074.7 nm [Fe XIII] with spectral dispersion of 28mÅ, 31mÅ and 202mÅ per pixel respectively, over a FOV of 1.05Ro to 1.5Ro. (c) Multi-slit dual beam spectro-polarimetry at 1074.7 nm. All the components of instrument have been optimized in view of the scientific objectives and requirements of space payloads. In this paper we present the details of optical configuration and the expected performance of the payload.

  20. The Classic: On Rest and Pain: Lecture XIV.

    Science.gov (United States)

    Hilton, John

    2009-09-01

    This Classic article is a reprint of the original work by John Hilton, On Rest and Pain: Lecture XIV. An accompanying biographical sketch on John Hilton, MD, is available at DOI 10.1007/s11999-009-0927-2 . The Classic Article is reprinted with courtesy from Hilton J. On The Influence of Mechanical and Physiological Rest in the Treatment of Accidents and Surgical Diseases, and the Diagnostic Value of Pain. London, England: Bell and Daldy; 1863.

  1. High resolution X-ray spectra of solar flares. V. interpretation of inner-shell transitions in Fe XX-Fe XXIII

    International Nuclear Information System (INIS)

    Doschek, G.A.; Feldman, U.; Cowan, R.D.

    1981-01-01

    We discuss high-resolution solar flare iron line spectra recorded between 1.82 and 1.97 A by a spectrometer flown by the Naval Research Laboratory on an Air Force spacecraft launched on 1979 February 24. The emission line spectrum is due to inner-shell transitions in the ions Fe XX-Fe XXV. Using theoretical spectra and calculations of line intensities obtained by methods discussed by Merts, Cowan, and Magee, we derive electron temperatures as a function for time of two large class X flares. These temperatures are deduced from intensities of lines of Fe XXIII, Fe XXII, and Fe XXIV. Previous measurements by us have involved only lines of Fe XXIV and Fe XXV. We discuss the determination of the differential emission measure between about 12 x 10 6 K and 20 x 10 6 K using these temperatures. The possibility of determining electron densities in flare and tokamak plasmas using the inner-shell spectra of Fe XXI and Fe XX is discussed. We also discuss recent theoretical work by Mewe and Schrijver based on atomic data of Grineva, Safronova, and Urnov

  2. EMISSION LINES BETWEEN 1 AND 2 keV IN COMETARY X-RAY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Ian; Christian, Damian J. [Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dennerl, Konrad [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching Germany (Germany); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 (United States); Wolk, Scott J., E-mail: ian.ewing.794@my.csun.edu, E-mail: daman.christian@csun.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-01-20

    We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

  3. 3d-4p transitions in the soft X-ray spectra of Mo XIV and of isoelectronic Y to Ag ions from a low-inductance vacuum spark

    International Nuclear Information System (INIS)

    Klapisch, M.; Mandelbaum, P.; Schwob, J.L.; Bar-Shalom, A.; Schweitzer, N.

    1981-04-01

    Eight lines of 3d 10 4s - 3d 9 4s4p and 3d 10 4p-3d 9 4p 2 transitions of CuI-like Y XI to Ag XIX ions are identified in the 30-80 A range of spectra emitted from a low-inductance vacuum spark. Identification is based on isoelectronic analysis and comparison with ab-initio relativistic calculations. In the present paper is analyzed the spectra of Mo XIV

  4. The weak Fe fluorescence line and long-term X-ray evolution of the Compton-thick active galactic nucleus in NGC 7674

    Science.gov (United States)

    Gandhi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Del Moro, A.; Elvis, M.; Guainazzi, M.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Lamperti, I.; Malaguti, G.; Masini, A.; Matt, G.; Puccetti, S.; Ricci, C.; Rivers, E.; Walton, D. J.; Zhang, W. W.

    2017-06-01

    We present NuSTAR X-ray observations of the active galactic nucleus (AGN) in NGC 7674. The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work suggested the alternate possibility that the source is a recently switched-off AGN with the observed X-rays being the lagged echo from the torus. Our high-quality data show the source to be reflection-dominated in hard X-rays, but with a relatively weak neutral Fe Kα emission line (equivalent width [EW] of ≈ 0.4 keV) and a strong Fe xxvi ionized line (EW ≈ 0.2 keV). We construct an updated long-term X-ray light curve of NGC 7674 and find that the observed 2-10 keV flux has remained constant for the past ≈ 20 yr, following a high-flux state probed by Ginga. Light travel time arguments constrain the minimum radius of the reflector to be ˜ 3.2 pc under the switched-off AGN scenario, ≈ 30 times larger than the expected dust sublimation radius, rendering this possibility unlikely. A patchy Compton-thick AGN (CTAGN) solution is plausible, requiring a minimum line-of-sight column density (NH) of 3 × 1024 cm-2 at present, and yields an intrinsic 2-10 keV luminosity of (3-5) × 1043 erg s-1. Realistic uncertainties span the range of ≈ (1-13) × 1043 erg s-1. The source has one of the weakest fluorescence lines amongst bona fide CTAGN, and is potentially a local analogue of bolometrically luminous systems showing complex neutral and ionized Fe emission. It exemplifies the difficulty of identification and proper characterization of distant CTAGN based on the strength of the neutral Feline.

  5. The Weak Fe Fluorescence Line and Long-Term X-Ray Evolution of the Compton-Thick Active Galactic Nucleus in NGC7674

    Science.gov (United States)

    Ghandi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.; hide

    2017-01-01

    We present NuSTAR X-ray observations of the active galactic nucleus (AGN) in NGC7674.The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work suggested the alternate possibility that the source is a recently switched-off AGN with the observed X-rays being the lagged echo from the torus. Our high-quality data show the source to be reflection-dominated in hard X-rays, but with a relatively weak neutral Fe K(alpha) emission line (equivalent width [EW] of approximately 0.4 keV) and a strong Fe XXVI ionized line (EW approximately 0.2 keV).We construct an updated long-term X-ray light curve of NGC7674 and find that the observed 2-10 keV flux has remained constant for the past approximately 20 yr, following a high-flux state probed by Ginga. Light travel time arguments constrain the minimum radius of the reflector to be approximately 3.2 pc under the switched-off AGN scenario, approximately 30 times larger than the expected dust sublimation radius, rendering this possibility unlikely. A patchy Compton-thick AGN (CTAGN) solution is plausible, requiring a minimum line-of-sight column density (N(sub H)) of 3 x 10(exp 24) cm(exp -2) at present, and yields an intrinsic 2-10 keV luminosity of (3-5) x 10(exp 43) erg s(exp -1). Realistic uncertainties span the range of approximately (1-13) x 10(exp 43) erg s1. The source has one of the weakest fluorescence lines amongst bona fide CTAGN, and is potentially a local analogue of bolometrically luminous systems showing complex neutral and ionized Fe emission. It exemplifies the difficulty of identification and proper characterization of distant CTAGN based on the strength of the neutral Fe K line

  6. Computed oscillator strengths and energy levels for Fe III, Fe IV, Fe V, and Fe VI with calculated wavelengths and wavelengths derived from established data

    International Nuclear Information System (INIS)

    Fawcett, B.C.

    1989-01-01

    Calculated weighted oscillator strengths are tabulated for spectral lines of Fe III, Fe IV, Fe V, and Fe VI. The lines belong to transition arrays 3d 6 -3d 5 4p and 3d 5 4s-3d 5 4p in Fe III, 3d 5 -3d 4 4p and 3d 4 4s-3d 4 4p in Fe IV, 3d 4 -3d 3 4p and 3d 3 4s-3d 3 4p in Fe V, and 3d 3 -3d 2 4p and 3d 2 4s-3d 2 4p in Fe VI. For the calculations, Slater parameters are optimized on the basis of minimizing the discrepancies between observed and computed wavelengths. Configuration interaction was included among the 3d n , 3d n-1 4s, 3d n-2 4s 2 , 3d n-1 4d, and 3d n-1 5s even configurations and among the 3d n-1 4p, 3d n-2 4s4p, and 3d n-1 5p odd configurations, with 3p 5 3d n+1 added for Fe VI. Calculated wavelengths are compared with observational data, and the compositions of energy levels are listed. This completes a series of similar computations for these complex configurations covering Fe I to Fe VI

  7. Non-LTE line formation of Fe in late-type stars - IV. Modelling of the solar centre-to-limb variation in 3D

    DEFF Research Database (Denmark)

    Lind, K.; Amarsi, A. M.; Asplund, M.

    2017-01-01

    Our ability to model the shapes and strengths of iron lines in the solar spectrum is a critical test of the accuracy of the solar iron abundance, which sets the absolute zero-point of all stellar metallicities. We use an extensive 463-level Fe atom with new photoionization cross-sections for Fe I...

  8. Non-LTE Calculations of the Fe I 6173 Å Line in a Flaring Atmosphere

    Science.gov (United States)

    Hong, Jie; Ding, M. D.; Li, Ying; Carlsson, Mats

    2018-04-01

    The Fe I 6173 Å line is widely used in the measurements of vector magnetic fields by instruments including the Helioseismic and Magnetic Imager (HMI). We perform non-local thermodynamic equilibrium calculations of this line based on radiative hydrodynamic simulations in a flaring atmosphere. We employ both a quiet-Sun atmosphere and a penumbral atmosphere as the initial one in our simulations. We find that, in the quiet-Sun atmosphere, the line center is obviously enhanced during an intermediate flare. The enhanced emission is contributed from both radiative backwarming in the photosphere and particle beam heating in the lower chromosphere. A blue asymmetry of the line profile also appears due to an upward mass motion in the lower chromosphere. If we take a penumbral atmosphere as the initial atmosphere, the line has a more significant response to the flare heating, showing a central emission and an obvious asymmetry. The low spectral resolution of HMI would indicate some loss of information, but the enhancement and line asymmetry are still kept. By calculating polarized line profiles, we find that the Stokes I and V profiles can be altered as a result of flare heating. Thus the distortion of this line has a crucial influence on the magnetic field measured from this line, and one should be cautious in interpreting the magnetic transients observed frequently in solar flares.

  9. On the Calculation of the Fe K-alpha Line Emissivity of Black Hole Accretion Disks

    Energy Technology Data Exchange (ETDEWEB)

    Krawczynski, H.; Beheshtipour, B., E-mail: krawcz@wustl.edu [Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States)

    2017-11-01

    Observations of the fluorescent Fe K α emission line from the inner accretion flows of stellar mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei have become an important tool to study the magnitude and inclination of the black hole spin, and the structure of the accretion flow close to the event horizon of the black hole. Modeling spectral, timing, and soon also X-ray polarimetric observations of the Fe K α emission requires the calculation of the specific intensity in the rest frame of the emitting plasma. We revisit the derivation of the equation used for calculating the illumination of the accretion disk by the corona. We present an alternative derivation leading to a simpler equation, and discuss the relation to previously published results.

  10. PREFACE: Symmetries in Science XIV

    Science.gov (United States)

    Schuch, Dieter; Ramek, Michael

    2010-04-01

    Symmetries Logo This volume of the proceedings "Symmetries in Science XIV" is dedicated to the memory of our colleagues and dear friends Marcos Moshinsky and Yuriĭ Smirnov who regularly participated in these Symposia and were a great inspiration to many. We shall miss them. Dieter Schuch and Michael Ramek The international symposium "Symmetries in Science XIV" held at Collegium Mehrerau in Bregenz, Austria from July 19-24, 2009, attended by 32 scientists from 11 countries, was an experiment, performed by theoreticians. Aim of this experiment was to find out if the desire to revive or even continue this conference series was stronger than the very restricted pecuniary boundary conditions. It obviously was! After its establishment by Bruno Gruber in 1979, the biennial series settled in the very stimulating atmosphere of the monastery Mehrerau, which provided the ideal environment for a limited number of invited participants to exchange ideas, without parallel sessions, and pursue deeper discussions (at the latest in the evening at "Gasthof Lamm"). When the conference series terminated in 2003, former participants were quite disappointed. Meeting again at several (larger) conferences in subsequent years, there were repeated expressions of "the lack of a Bregenz-type meeting in our field nowadays" and the question of a possible "revitalization", even without external funding. After some hesitation, but also driven by our own desire to reinstate the series, we consulted Bruno who not only approved wholeheartedly but also offered his full support. It all finally led to the symposium in July 2009. The atmosphere was really like in the "good old days" and the interesting and thought-provoking presentations culminated in the publication of these Proceedings. We are grateful to Carl Bender for establishing contact with IOP making it possible for us to publish these Proceedings in the Journal of Physics Conference Series. A majority of the participants contributed to these

  11. Los precursores latinos de la f??bula espa??ola del siglo XIV

    OpenAIRE

    Van Dijk, Gert-Jan

    2015-01-01

    Recorrido por las obras latinas antiguas y medievales que conforman el conjunto fabul??stico atribuido durante la Edad Media a Esopo, en el que los escritores espa??oles del siglo XIV encuentran su fuente de inspiraci??n a la hora de incorporar f??bulas a sus colecciones de cuentos o a otros tipos de obras

  12. The toxicity of silver and silica nanoparticles in comparable human and mouse cell lines

    DEFF Research Database (Denmark)

    Foldbjerg, Rasmus; Beer, Christiane; Sutherland, Duncan S

    The toxicity of silica (SiO2) and PVP-coated silver (Ag) nanoparticles (NPs) was investigated in two pairs of human or mouse cell lines originating from lung epithelium (A549 and ASB-XIV) and macrophages (THP-1 and J744A.1). Both NPs were characterized in H2O and cell media and demonstrated to be...

  13. Properties of Fe, Ni and Zn isotopes near the drip-lines

    International Nuclear Information System (INIS)

    Tarasov, V.N.; Tarasaov, D.V.; Gridnev, K.A.; Gridnev, D.K.; Kartavenko, V.G.; Greiner, W.

    2008-01-01

    The position of the neutron and proton drip-lines as well as properties of the isotopes Fe, Ni and Zn with neutron excess and neutron deficit are studied within the Hartree–Fock approach with the Skyrme interaction (Ska, SkM*, Sly4). The pairing is taken into account on the basis of the BCS approach with the pairing constant G = (19.5/A)[1 ± 0.51(N-Z)/A]. Our calculations predict that for Ni isotopes around N = 62 there appears a sudden increase of the deformation parameter up to β = 0.4. The zone with such big deformation, where Ni isotopes are stable against one neutron emission stretches up to N = 78. The magic numbers effects for the isotopes 48 Ni, 56 Ni, 78 Ni, 110 Ni are discussed. The universality of the reasons standing behind the enhancement of stability of the isotopes 40 O and 110 Ni which are beyond the drip-line is demonstrated. Calculated values of the two-neutron separation energy, and proton and neutron root mean square radii for the chain of Ni isotopes show a good agreement with existing Hartree–Fock–Bogoliubov calculations of these values. (author)

  14. A quasi-continuous observation of the α-transition of Fe1+xS by Moessbauer line tracking

    International Nuclear Information System (INIS)

    Mendoza Zelis, P.; Pasquevich, G. A.; Veiga, A.; Fernandez van Raap, M. B.; Sanchez, F. H.

    2010-01-01

    Moessbauer absorption line tracking methodology, under a constant velocity strategy, is used for a quasi-continuous observation of the α-transition on slightly non stoichiometric Fe 1+x S alloy. To this end, two strategies were applied: an intelligent absorption line tracking with a control algorithm that uses the data measured in the previous region to establish the position of the next partial spectral range; and a predetermined line tracking in which temperature evolution of a partial spectral region of interest (ROI) is programmed. The latter uses results from the former, in order to achieve a quasi-continuous partial spectral observation. These experiments clearly demonstrate that line tracking allows a more efficient use of the radioactive source, as the effort is concentrated in a partial region of the spectra from which the desired information can be obtained.

  15. The profiles of Fe K α line from the inhomogeneous accretion flow

    Science.gov (United States)

    Yu, Xiao-Di; Ma, Ren-Yi; Li, Ya-Ping; Zhang, Hui; Fang, Tao-Tao

    2018-05-01

    The clumpy disc, or inhomogeneous accretion flow, has been proposed to explain the properties of accreting black hole systems. However, the observational evidence remains to be explored. In this work, we calculate the profiles of Fe K α lines emitted from the inhomogeneous accretion flow through the ray-tracing technique, in order to find possible observable signals of the clumps. Compared with the skewed double-peaked profile of the continuous standard accretion disc, the lines show a multipeak structure when the emissivity index is not very steep. The peaks and wings are affected by the position and size of the cold clumps. When the clump is small and is located in the innermost region, due to the significant gravitational redshift, the blue wing can overlap with the red wing of the outer cold disc/clump, forming a fake peak or greatly enhancing the red peak. Given high enough resolution, it is easier to constrain the clumps around the supermassive black holes than the clumps in stellar mass black holes due to the thermal Doppler effect.

  16. CHIANTI—AN ATOMIC DATABASE FOR EMISSION LINES. XIII. SOFT X-RAY IMPROVEMENTS AND OTHER CHANGES

    International Nuclear Information System (INIS)

    Landi, E.; Young, P. R.; Dere, K. P.; Del Zanna, G.; Mason, H. E.

    2013-01-01

    The CHIANTI spectral code consists of two parts: an atomic database and a suite of computer programs in Python and IDL. Together, they allow the calculation of the optically thin spectrum of astrophysical objects and provide spectroscopic plasma diagnostics for the analysis of astrophysical spectra. The database includes atomic energy levels, wavelengths, radiative transition probabilities, collision excitation rate coefficients, ionization, and recombination rate coefficients, as well as data to calculate free-free, free-bound, and two-photon continuum emission. Version 7.1 has been released, which includes improved data for several ions, recombination rates, and element abundances. In particular, it provides a large expansion of the CHIANTI models for key Fe ions from Fe VIII to Fe XIV to improve the predicted emission in the 50-170 Å wavelength range. All data and programs are freely available at http://www.chiantidatabase.org and in SolarSoft, while the Python interface to CHIANTI can be found at http://chiantipy.sourceforge.net.

  17. Results of Spectral Corona Observations in Solar Activity Cycles 17-24

    Science.gov (United States)

    Aliev, A. Kh.; Guseva, S. A.; Tlatov, A. G.

    2017-12-01

    The results of the work of the global observation network are considered, and a comparative analysis of the data of various coronal observatories is performed. The coronal activity index has been reconstructed for the period 1939-2016 based on the data of various observatories in Kislovodsk system. For this purpose, the corona daily intensity maps from the Sacramento Peak and Lomnický Štít observatories according to the Solar-Geophysical Data journal have been digitized; they supplement the data of other observatories. The homogeneity and continuity of the corona observations at the Kislovodsk station, including activity cycle 24, is confirmed. Unfortunately, the only observatory at present that continues observation of the spectral corona in Fe XIV 5303 Å and Fe XIV 6374 Å lines is the Kislovodsk astronomical station Mountain Astronomical Station (MAS) of the Central Astronomical Observatory, Russian Academy of Sciences (Pulkovo). The data on the combined corona in 5303 Å line are analyzed. It is shown that there is a high correlation of the intensity index of green corona with solar radiation measurements in the vacuum UV region. Data on the beginning of the new 25th activity cycle in the corona at high latitudes are presented.

  18. Line shape and thermal Kinetics analysis of the Fe2+ -band in Brazilian Green beryl

    International Nuclear Information System (INIS)

    Isotani, S.; Furtado, W.; Antonini, R.; Dias, O.L.

    1988-03-01

    The optical absorption spectra study through isothermal treatments of the σ- and Π-polarized bands of Fe 2+ -band is reported. It was shown a linear correlation between these bands through thermal treatments. Irradiation with γ-rays from 60 Co, showed the decrease of this band. The line shape analysis and the discussions lend us to assign the Π- and σ-polarized bands to Fe 2+ ions in the structural channels with and without neighbour water molecules, respectively. The kinetics analysis through a ''bimolecular-like'' model gives untrapping parameter with Arrhenius behavior. The retrapping and recombination parameters showed a behavior proportional to T 1/2 - T 1/2 o which were explained from free electron distribution of velocities and minimum untrapped electron energy due to a potential barrier of the trap. The kinetics cut-off temperature, T 0 , agrees with the previous experimental observation. (author) [pt

  19. BibSword Implementation of SWORD client in Invenio for the automated submission of digital objects to arXiv

    CERN Document Server

    Barras, Mathieu; Abou Khaled, Omar; Mugellini, Elena

    2010-01-01

    Since recently, arXiv offers a new submission interface implementing SWORD. SWORD is a brand new protocol that defines a simple way to deposit digital document on web repositories. The most part of digital documents submitted on Invenio are also deposited on arXiv. For this reason, it is a relevant added value for Invenio to offers such an automated “Forward to ArXiv” option to its users. The aim of this project is then to analyse, design and implements a library oriented SWORD client module (BibSword). This module will offer an user interface and will be integrated in the Invenio submission process.

  20. Electron spin resonance of Fe4+ in amethyst quartz

    International Nuclear Information System (INIS)

    Cox, R.T.

    1975-01-01

    The ESR spectrum of Fe 4+ was looked for in amethyst quartz. Besides saturated Fe 3+ lines, ESR lines of a new paramagnetic center whose spin-lattice relaxation time is relatively short were observed. They could be attributed to Fe 4+ [fr

  1. Accurate Wavelength Measurements and Modeling of Fe XV to Fe XIX Spectra Recorded in High-Density Plasmas between 13.5 and 17 Å

    Science.gov (United States)

    May, M. J.; Beiersdorfer, P.; Dunn, J.; Jordan, N.; Hansen, S. B.; Osterheld, A. L.; Faenov, A. Ya.; Pikuz, T. A.; Skobelev, I. Yu.; Flora, F.; Bollanti, S.; Di Lazzaro, P.; Murra, D.; Reale, A.; Reale, L.; Tomassetti, G.; Ritucci, A.; Francucci, M.; Martellucci, S.; Petrocelli, G.

    2005-06-01

    Iron spectra have been recorded from plasmas created at three different laser plasma facilities: the Tor Vergata University laser in Rome (Italy), the Hercules laser at ENEA in Frascati (Italy), and the Compact Multipulse Terawatt (COMET) laser at LLNL in California (USA). The measurements provide a means of identifying dielectronic satellite lines from Fe XVI and Fe XV in the vicinity of the strong 2p-->3d transitions of Fe XVII. About 80 Δn>=1 lines of Fe XV (Mg-like) to Fe XIX (O-like) were recorded between 13.8 and 17.1 Å with a high spectral resolution (λ/Δλ~4000) about 30 of these lines are from Fe XVI and Fe XV. The laser-produced plasmas had electron temperatures between 100 and 500 eV and electron densities between 1020 and 1022 cm-3. The Hebrew University Lawrence Livermore Atomic Code (HULLAC) was used to calculate the atomic structure and atomic rates for Fe XV-XIX. HULLAC was used to calculate synthetic line intensities at Te=200 eV and ne=1021 cm-3 for three different conditions to illustrate the role of opacity: optically thin plasmas with no excitation-autoionization/dielectronic recombination (EA/DR) contributions to the line intensities, optically thin plasmas that included EA/DR contributions to the line intensities, and optically thick plasmas (optical depth ~200 μm) that included EA/DR contributions to the line intensities. The optically thick simulation best reproduced the recorded spectrum from the Hercules laser. However, some discrepancies between the modeling and the recorded spectra remain.

  2. Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

    Science.gov (United States)

    Bruhweiler, F.; Verner, E.

    2008-03-01

    We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm -3) ] = 11.0, log [ΦH/(cm -2 s-1) ] = 20.5, and ξ/(1 km s-1) = 20, using Cloudy and an 830 level model atom for Fe II with energies up to 14.06 eV, gives a better fit to the UV Fe II emission than models with fewer levels. Our analysis indicates (1) the observed UV Fe II emission must be corrected for an underlying Fe II pseudocontinuum; (2) Fe II emission peaks can be misidentified as that of other ions in active galactic nuclei (AGNs) with narrow-lined BLRs possibly affecting deduced physical parameters; (3) the shape of 4200-4700 Å Fe II emission in I Zw 1 and other AGNs is a relative indicator of narrow-line region (NLR) and BLR Fe II emission; (4) predicted ratios of Lyα, C III], and Fe II emission relative to Mg II λ2800 agree with extinction corrected observed I Zw 1 fluxes, except for C IV λ1549 (5) the sensitivity of Fe II emission strength to microturbulence ξ casts doubt on existing relative Fe/Mg abundances derived from Fe II (UV)/Mg II flux ratios. Our calculated Fe II emission spectra, suitable for BLRs in AGNs, are available at http://iacs.cua.edu/people/verner/FeII. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 05-26555.

  3. A quasi-continuous observation of the {alpha}-transition of Fe{sub 1+x}S by Moessbauer line tracking

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Zelis, P., E-mail: pmendoza@fisica.unlp.edu.ar; Pasquevich, G. A.; Veiga, A.; Fernandez van Raap, M. B.; Sanchez, F. H. [Universidad Nacional de La Plata, CONICET, Depto. de Fisica, Fac. Ciencias Exactas, Instituto de Fisica La Plata (Argentina)

    2010-01-15

    Moessbauer absorption line tracking methodology, under a constant velocity strategy, is used for a quasi-continuous observation of the {alpha}-transition on slightly non stoichiometric Fe{sub 1+x}S alloy. To this end, two strategies were applied: an intelligent absorption line tracking with a control algorithm that uses the data measured in the previous region to establish the position of the next partial spectral range; and a predetermined line tracking in which temperature evolution of a partial spectral region of interest (ROI) is programmed. The latter uses results from the former, in order to achieve a quasi-continuous partial spectral observation. These experiments clearly demonstrate that line tracking allows a more efficient use of the radioactive source, as the effort is concentrated in a partial region of the spectra from which the desired information can be obtained.

  4. In vitro toxicity test and searching the possibility of cancer cell line extermination by magnetic heating with using Fe3O4 magnetic fluid

    International Nuclear Information System (INIS)

    Pham Hoai Linh; Nguyen Chi Thuan; Nguyen Anh Tuan; Pham Van Thach; Nguyen Xuan Phuc; Le Van Hong; Tran Cong Yen; Nguyen Thi Quy; Hoang Thi My Nhung; Phi Thi Xuyen

    2009-01-01

    A Fe 3 O 4 based magnetic fluid with different concentrations ranged between 0.15 ng/cell to 10 ng/cell (nano gram/cell) was used in the in vitro toxicity test on several cancer cell lines, Sarcoma 180, HeLa and H358. It shows that the fluid with a concentration of Fe 3 O 4 below 1.2 ng/cell is completely non-toxic for these cell lines. Even through in the presence of the highest concentration of 10 ng/cell, the cell viability still reaches more than 60%. The magnetic fluid with Fe 3 O 4 concentration of about 0.1 ng/cell was also used to search ex-vivo the possibility of Sarcoma 180 extermination by magnetic heating with an AC field of 120Oe and 184 KHz. The result shows that after a heat treatment for 30 min., 40% of Sarcoma 180 cells was killed.

  5. XIV International Conference on Mathematical Programming

    CERN Document Server

    Pardalos, Panos; Rapcsák, Tamás

    2001-01-01

    This volume contains refereed papers based on the lectures presented at the XIV International Conference on Mathematical Programming held at Matrahaza, Hungary, between 27-31 March 1999. This conference was organized by the Laboratory of Operations Research and Deci­ sion Systems at the Computer and Automation Institute, Hungarian Academy of Sciences. The editors hope this volume will contribute to the theory and applications of mathematical programming. As a tradition of these events, the main purpose of the confer­ ence was to review and discuss recent advances and promising research trends concerning theory, algorithms and applications in different fields of Optimization Theory and related areas such as Convex Analysis, Complementarity Systems and Variational Inequalities. The conference is traditionally held in the Matra Mountains, and housed by the resort house of the Hungarian Academy of Sciences. This was the 14th event of the long lasting series of conferences started in 1973. The organizers wish to...

  6. Juristas y Teólogos en el Siglo XIV Ibérico: La retórica del antisemitismo

    Directory of Open Access Journals (Sweden)

    Andrea Gayoso

    2014-02-01

    Full Text Available Este artículo trata de la introducción de las distintas teorías filosóficas y teológicas producidas en las universidades europeas de los siglos XIII y XIV en la Península Ibérica, y de cómo ellas afectaron y contribuyeron a transformar las relaciones multiculturales que caracterizaban la vida social, intelectual y legal hispánica hasta mediados del siglo XIV. Más específicamente, mi propósito es tratar aquí la influencia de la introducción del escotismo en este contexto, el cual los historiadores han denominado Convivencia.

  7. Collagen XII and XIV, New Partners of Cartilage Oligomeric Matrix Protein in the Skin Extracellular Matrix Suprastructure*

    Science.gov (United States)

    Agarwal, Pallavi; Zwolanek, Daniela; Keene, Douglas R.; Schulz, Jan-Niklas; Blumbach, Katrin; Heinegård, Dick; Zaucke, Frank; Paulsson, Mats; Krieg, Thomas; Koch, Manuel; Eckes, Beate

    2012-01-01

    The tensile and scaffolding properties of skin rely on the complex extracellular matrix (ECM) that surrounds cells, vasculature, nerves, and adnexus structures and supports the epidermis. In the skin, collagen I fibrils are the major structural component of the dermal ECM, decorated by proteoglycans and by fibril-associated collagens with interrupted triple helices such as collagens XII and XIV. Here we show that the cartilage oligomeric matrix protein (COMP), an abundant component of cartilage ECM, is expressed in healthy human skin. COMP expression is detected in the dermal compartment of skin and in cultured fibroblasts, whereas epidermis and HaCaT cells are negative. In addition to binding collagen I, COMP binds to collagens XII and XIV via their C-terminal collagenous domains. All three proteins codistribute in a characteristic narrow zone in the superficial papillary dermis of healthy human skin. Ultrastructural analysis by immunogold labeling confirmed colocalization and further revealed the presence of COMP along with collagens XII and XIV in anchoring plaques. On the basis of these observations, we postulate that COMP functions as an adapter protein in human skin, similar to its function in cartilage ECM, by organizing collagen I fibrils into a suprastructure, mainly in the vicinity of anchoring plaques that stabilize the cohesion between the upper dermis and the basement membrane zone. PMID:22573329

  8. Collagen XII and XIV, new partners of cartilage oligomeric matrix protein in the skin extracellular matrix suprastructure.

    Science.gov (United States)

    Agarwal, Pallavi; Zwolanek, Daniela; Keene, Douglas R; Schulz, Jan-Niklas; Blumbach, Katrin; Heinegård, Dick; Zaucke, Frank; Paulsson, Mats; Krieg, Thomas; Koch, Manuel; Eckes, Beate

    2012-06-29

    The tensile and scaffolding properties of skin rely on the complex extracellular matrix (ECM) that surrounds cells, vasculature, nerves, and adnexus structures and supports the epidermis. In the skin, collagen I fibrils are the major structural component of the dermal ECM, decorated by proteoglycans and by fibril-associated collagens with interrupted triple helices such as collagens XII and XIV. Here we show that the cartilage oligomeric matrix protein (COMP), an abundant component of cartilage ECM, is expressed in healthy human skin. COMP expression is detected in the dermal compartment of skin and in cultured fibroblasts, whereas epidermis and HaCaT cells are negative. In addition to binding collagen I, COMP binds to collagens XII and XIV via their C-terminal collagenous domains. All three proteins codistribute in a characteristic narrow zone in the superficial papillary dermis of healthy human skin. Ultrastructural analysis by immunogold labeling confirmed colocalization and further revealed the presence of COMP along with collagens XII and XIV in anchoring plaques. On the basis of these observations, we postulate that COMP functions as an adapter protein in human skin, similar to its function in cartilage ECM, by organizing collagen I fibrils into a suprastructure, mainly in the vicinity of anchoring plaques that stabilize the cohesion between the upper dermis and the basement membrane zone.

  9. Gyvulininkystė pietryčių Lietuvoje XIII-XIV a

    OpenAIRE

    Vitkūnas, Manvydas

    2006-01-01

    Gyvulininkystė XIII-XIV a. buvo viena svarbiausių ūkio šakų. Pietryčių Lietuvos archeologiniuose paminkluose surinktos osteologinės medžiagos tyrimų duomenimis, naminiai gyvuliai daugeliui gyventojų buvo pagrindiniu mėsos šaliniu. Pietryčių Lietuvos archeologiniuose paminkluose (Nemenčinės, Bradeliškių, Maišiagalos, Aukštadvario piliakalniuose, viduramžių Kernavės miesto vietoje, Vilniaus žemutinėje pilyje) naminių gyvulių kaulai sudarė dažniausiai 80-95%, o Maišiagalos piliakalnyje – net 99%...

  10. arXiv Wilson lines and UV sensitivity in magnetic compactifications

    CERN Document Server

    Ghilencea, D.M.

    2017-06-07

    We investigate the ultraviolet (UV) behaviour of 6D N=1 supersymmetric effective (Abelian) gauge theories compactified on a two-torus (T$_{2}$) with magnetic flux. To this purpose we compute offshell the one-loop correction to the Wilson line state self-energy. The offshell calculation is actually necessary to capture the usual effective field theory expansion in powers of (∂/Λ). Particular care is paid to the regularization of the (divergent) momentum integrals, which is relevant for identifying the corresponding counterterm(s). We find a counterterm which is a new higher dimensional effective operator of dimension d=6, that is enhanced for a larger compactification area (where the effective theory applies) and is consistent with the symmetries of the theory. Its consequences are briefly discussed and comparison is made with orbifold compactifications without flux.

  11. The rebirth of Supernova 1987A : a study of the ejecta-ring collision

    Science.gov (United States)

    Gröningsson, Per

    Supernovae are some of the most energetic phenomena in the Universe and they have throughout history fascinated people as they appeared as new stars in the sky. Supernova (SN) 1987A exploded in the nearby satellite galaxy, the Large Magellanic Cloud (LMC), at a distance of only 168,000 light years. The proximity of SN 1987A offers a unique opportunity to study the medium surrounding the supernova in great detail. Powered by the dynamical interaction of the ejecta with the inner circumstellar ring, SN 1987A is dramatically evolving at all wavelengths on time scales less than a year. This makes SN 1987A a great ``laboratory'' for studies of shock physics. Repeated observations of the ejecta-ring collision have been carried out using the UVES echelle spectrograph at VLT. This thesis covers seven epochs of high resolution spectra taken between October 1999 and November 2007. Three different emission line components are identified from the spectra. A narrow (~10 km/s) velocity component emerges from the unshocked ring. An intermediate (~250 km/s) component arises in the shocked ring, and a broad component extending to ~15,000 km/s comes from the reverse shock. Thanks to the high spectral resolution of UVES, it has been possible to separate the shocked from the unshocked ring emission. For the unshocked gas, ionization stages from neutral up to Ne V and Fe VII were found. The line fluxes of the low-ionization lines decline during the period of the observations. However, the fluxes of the [O III] and [Ne III] lines appear to increase and this is found to be consistent with the heating of the pre-shock gas by X-rays from the shock interactions. The line emission from the ejecta-ring collision increases rapidly as more gas is swept up by the shocks. This emission comes from ions with a range of ionization stages (e.g., Fe II-XIV). The low-ionization lines show an increase in their line widths which is consistent with that these lines originate from radiative shocks. The

  12. Two-gap superconductivity with line nodes in CsCa2Fe4As4F2

    Science.gov (United States)

    Kirschner, Franziska K. K.; Adroja, Devashibhai T.; Wang, Zhi-Cheng; Lang, Franz; Smidman, Michael; Baker, Peter J.; Cao, Guang-Han; Blundell, Stephen J.

    2018-02-01

    We report the results of a muon-spin rotation (μ SR ) experiment to determine the superconducting ground state of the iron-based superconductor CsCa2Fe4As4F2 with Tc≈28.3 K . This compound is related to the fully gapped superconductor CaCsFe4As4 , but here the Ca-containing spacer layer is replaced with one containing Ca2F2 . The temperature evolution of the penetration depth strongly suggests the presence of line nodes and is best modeled by a system consisting of both an s - and a d -wave gap. We also find a potentially magnetic phase which appears below ≈10 K but does not appear to compete with the superconductivity. This compound contains the largest alkali atom in this family of superconductors, and our results yield a value for the in-plane penetration depth of λa b(T =0 ) =244 (3 ) nm .

  13. Assessment of affinities of beta-CIT, beta-CIT-FE, and beta-CIT-FP for monoamine transporters permanently expressed in cell lines

    International Nuclear Information System (INIS)

    Okada, Tomoya; Fujita, Masahiro; Shimada, Shoichi; Sato, Kohji; Schloss, Patrick; Watanabe, Yoshiyuki; Itoh, Yasushi; Tohyama, Masaya; Nishimura, Tsunehiko

    1998-01-01

    We investigated the effects of three cocaine analogs, beta-CIT (2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane), beta-CIT-FE (2-beta-carbomethoxy-3-beta-(4-iodophenyl)-N-(2-fluoroethyl)-nortropane), and beta-CIT-FP (2-beta-carbomethoxy-3-beta-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane), on the uptake of [ 3 H]dopamine(DA), serotonin(5-HT), and 1-norepinephrine (NE) using cell lines permanently expressing DA, 5-HT, and NE transporters, respectively, to determine their affinities for these three transporters. We generated cell lines stably expressing DA, 5-HT, and NE transporters, respectively, by the Chen-Okayama method, and then tested the abilities of (-)cocaine, beta-CIT, beta-CIT-FE, beta-CIT-FP, and clomipramine to inhibit the uptake of [ 3 H]DA, 5-HT, and 1-NE. Ki values of beta-CIT, beta-CIT-FE, and beta-CIT-FP for [ 3 H]DA, 5-HT, 1-NE uptake were 6, 29, and 33 nM, 91, 133, and 130 nM, and 28, 113 and 70 nM, respectively, whereas those of cocaine and clomipramine were 316, 581, and 176 nM and > 10,000, 437, and 851 nM, respectively. Beta-CIT, beta-CIT-FE, and beta-CIT-FP were shown to be potent DA, 5-HT, and NE uptake inhibitors. Beta-CIT and beta-CIT-FP were highly potent and selective dopamine uptake inhibitors, and therefore might be useful for imaging of DA transporter with single photon emission computed tomography (SPECT) or positron emission tomography (PET)

  14. Iron and zinc availability in maize lines

    Directory of Open Access Journals (Sweden)

    Valéria Aparecida Vieira Queiroz

    2011-09-01

    Full Text Available The aim of this study was to characterize the Zn and Fe availability by phytic acid/Zn and phytic acid/Fe molar ratios, in 22 tropical maize inbred lines with different genetic backgrounds. The Zn and Fe levels were determined by atomic absorption spectrophotometry and the P through colorimetry method. Three screening methods for phytic acid (Phy analysis were tested and one, based on the 2,2'-bipyridine reaction, was select. There was significant variability in the contents of zinc (17.5 to 42 mg.kg-1, iron (12.2 to 36.7 mg.kg-1, phosphorus (230 to 400 mg.100 g-1, phytic acid (484 to 1056 mg.100 g-1, phytic acid P (140 to 293 mg.100 g-1 and available-P (43.5 to 199.5 mg.100 g-1, and in the available-P/total-P ratio (0.14 to 0.50, Phy/Zn (18.0 to 43.5 and Phy/Fe (16.3 to 45.5 molar ratios. Lines 560977, 560978 and 560982 had greater availability of Zn and lines 560975, 560977, 561010 and 5610111 showed better Fe availability. Lines 560975, 560977 and 560978 also showed better available-P/total-P ratio. Thus, the lines 560975, 560977 and 560978 were considered to have the potential for the development of cultivars of maize with high availability of Fe and/or Zn.

  15. THE MYSTERIOUS CASE OF THE SOLAR ARGON ABUNDANCE NEAR SUNSPOTS IN FLARES

    International Nuclear Information System (INIS)

    Doschek, G. A.; Warren, H. P.

    2016-01-01

    Recently we discussed an enhancement of the abundance of Ar xiv relative to Ca xiv near a sunspot during a flare, observed in spectra recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The observed Ar xiv/Ca xiv ratio yields an argon/calcium abundance ratio seven times greater than expected from the photospheric abundance. Such a large abundance anomaly is unprecedented in the solar atmosphere. We interpreted this result as being due to an inverse first ionization potential (FIP) effect. In the published work, two lines of Ar xiv were observed, and one line was tentatively identified as an Ar xi line. In this paper, we report observing a similar enhancement in a full-CCD EIS flare spectrum in 13 argon lines that lie within the EIS wavelength ranges. The observed lines include two Ar xi lines, four Ar xiii lines, six Ar xiv lines, and one Ar xv line. The enhancement is far less than reported in Doschek et al. but exhibits similar morphology. The argon abundance is close to a photospheric abundance in the enhanced area, and the abundance could be photospheric. This enhancement occurs in association with a sunspot in a small area only a few arcseconds (1″ = about 700 km) in size. There is no enhancement effect observed in the normally high-FIP sulfur and oxygen line ratios relative to lines of low-FIP elements available to EIS. Calculations of path lengths in the strongest enhanced area in Doschek et al. indicate a depletion of low-FIP elements.

  16. Geothermal Program Review XIV: proceedings. Keeping Geothermal Energy Competitive in Foreign and Domestic Markets

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    The U.S. Department of Energy`s Office of Geothermal Technologies conducted its annual Program Review XIV in Berkeley, April 8-10, 1996. The geothermal community came together for an in-depth review of the federally-sponsored geothermal research and development program. This year`s theme focused on ``Keeping Geothermal Energy Competitive in Foreign and Domestic Markets.`` This annual conference is designed to promote technology transfer by bringing together DOE-sponsored researchers; utility representatives; geothermal developers; equipment and service suppliers; representatives from local, state, and federal agencies; and others with an interest in geothermal energy. Program Review XIV consisted of eight sessions chaired by industry representatives. Introductory and overview remarks were presented during every session followed by detailed reports on specific DOE-funded research projects. The progress of R&D projects over the past year and plans for future activities were discussed. The government-industry partnership continues to strengthen -- its success, achievements over the past twenty years, and its future direction were highlighted throughout the conference. The comments received from the conference evaluation forms are published in this year`s proceedings. Individual papers have been processed for inclusion in the Energy Science and Technology Database.

  17. Cluster-based bulk metallic glass formation in Fe-Si-B-Nb alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, C L; Wang, Q; Li, F W; Li, Y H; Wang, Y M; Dong, C [State Key Laboratory of Materials Modification, Dalian University of Technology (DUT), Dalian 116024 (China); Zhang, W; Inoue, A, E-mail: dong@dlut.edu.c [Institute for Materials Research (IMR), Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

    2009-01-01

    Bulk metallic glass formations have been explored in Fe-B-Si-Nb alloy system using the so-called atomic cluster line approach in combination with minor alloying guideline. The atomic cluster line refers to a straight line linking binary cluster to the third element in a ternary system. The basic ternary compositions in Fe-B-Si system are determined by the inetersection points of two cluster lines, namely Fe-B cluster to Si and Fe-Si cluster to B, and then further alloyed with 3-5 at. % Nb for enhancing glass forming abilities. BMG rods with a diameter of 3 mm are formed under the case of minor Nb alloying the basic intersecting compositions of Fe{sub 8}B{sub 3}-Si with Fe{sub 12}Si-B and Fe{sub 8}B{sub 2}-Si with Fe{sub 9}Si-B. The BMGs also exhibit high Vickers hardness (H{sub v}) of 1130-1164 and high Young's modulous (E) of 170-180 GPa

  18. Grotrian diagrams of highly ionized iron Fe(VIII)-Fe(XXVI)

    International Nuclear Information System (INIS)

    Mori, Kazuo; Otsuka, Masamoto; Kato, Takako.

    1977-08-01

    Energy levels and Grotrian diagrams of Fe(VIII) to Fe(XXVI) are presented. This report summarized the data published recently up to 1976, and the wavelength tables compiled were converted to the Grotrian diagrams. The diagrams showing transition from one energy level to another are called Grotrian diagrams. Typical examples of the diagrams are found in the book by Bashkin et al. In the present diagrams, all lines are drawn in parallel, and connected to the extended lines from lower levels. As the results, locally dense packing of lines and figures is avoided. The ordinate of the diagrams indicates level energy, and the J values are shown on the left side of the levels. The wavelength values in angstrom unit are written in parallel with the vertical transition lines. This vertical lines show the resonance transition having absorption oscillator strength f larger than 0.1. The present diagrams are the combination of the tables of wavelength and energy level. Accordingly, the desired wavelength and level energy are easily found. The figures of wavelength are lined up in various groups, so that the characteristics of the transition can be discriminated at a glance. Wavelength and level energy have been mostly derived from experimental spectra in laboratory or solar plasma, except a few by Fawcett's prediction. (Kato, T.)

  19. Physical conditions in CaFe interstellar clouds

    OpenAIRE

    Gnacinski, P.; Krogulec, M.

    2007-01-01

    Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.

  20. Identification and Complete Genome Sequence Analysis of a Genotype XIV Newcastle Disease Virus from Nigeria

    Science.gov (United States)

    Shittu, Ismaila; Sharma, Poonam; Volkening, Jeremy D.; Solomon, Ponman; Sulaiman, Lanre K.; Joannis, Tony M.; Williams-Coplin, Dawn; Miller, Patti J.; Dimitrov, Kiril M.

    2016-01-01

    The first complete genome sequence of a strain of Newcastle disease virus (NDV) from genotype XIV is reported here. Strain duck/Nigeria/NG-695/KG.LOM.11-16/2009 was isolated from an apparently healthy domestic duck from a live bird market in Kogi State, Nigeria, in 2009. This strain is classified as a member of subgenotype XIVb of class II. PMID:26823576

  1. Identification and Complete Genome Sequence Analysis of a Genotype XIV Newcastle Disease Virus from Nigeria

    OpenAIRE

    Shittu, Ismaila; Sharma, Poonam; Volkening, Jeremy D.; Solomon, Ponman; Sulaiman, Lanre K.; Joannis, Tony M.; Williams-Coplin, Dawn; Miller, Patti J.; Dimitrov, Kiril M.; Afonso, Claudio L.

    2016-01-01

    The first complete genome sequence of a strain of Newcastle disease virus (NDV) from genotype XIV is reported here. Strain duck/Nigeria/NG-695/KG.LOM.11-16/2009 was isolated from an apparently healthy domestic duck from a live bird market in Kogi State, Nigeria, in 2009. This strain is classified as a member of subgenotype XIVb of class II.

  2. Non-equilibrium Modeling of the Fe XVII 3C/3D Line Ratio in an Intense X-Ray Free-Electron Laser Excited Plasma

    Science.gov (United States)

    Loch, S. D.; Ballance, C. P.; Li, Y.; Fogle, M.; Fontes, C. J.

    2015-03-01

    Recent measurements using an X-ray Free Electron Laser (XFEL) and an Electron Beam Ion Trap at the Linac Coherent Light Source facility highlighted large discrepancies between the observed and theoretical values for the Fe xvii 3C/3D line intensity ratio. This result raised the question of whether the theoretical oscillator strengths may be significantly in error, due to insufficiencies in the atomic structure calculations. We present time-dependent spectral modeling of this experiment and show that non-equilibrium effects can dramatically reduce the predicted 3C/3D line intensity ratio, compared with that obtained by simply taking the ratio of oscillator strengths. Once these non-equilibrium effects are accounted for, the measured line intensity ratio can be used to determine a revised value for the 3C/3D oscillator strength ratio, giving a range from 3.0 to 3.5. We also provide a framework to narrow this range further, if more precise information about the pulse parameters can be determined. We discuss the implications of the new results for the use of Fe xvii spectral features as astrophysical diagnostics and investigate the importance of time-dependent effects in interpreting XFEL-excited plasmas.

  3. ORIGIN OF THE GALACTIC DIFFUSE X-RAY EMISSION: IRON K-SHELL LINE DIAGNOSTICS

    Energy Technology Data Exchange (ETDEWEB)

    Nobukawa, Masayoshi [Department of Teacher Training and School Education, Nara University of Education, Takabatake-cho, Nara, 630-8528 (Japan); Uchiyama, Hideki [Faculty of Education, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529 (Japan); Nobukawa, Kumiko K.; Koyama, Katsuji [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Yamauchi, Shigeo, E-mail: nobukawa@nara-edu.ac.jp [Department of Physics, Nara Women’s University, Kitauoyanishimachi, Nara, 630-8506 (Japan)

    2016-12-20

    This paper reports detailed K-shell line profiles of iron (Fe) and nickel (Ni) of the Galactic Center X-ray Emission (GCXE), Galactic Bulge X-ray Emission (GBXE), Galactic Ridge X-ray Emission (GRXE), magnetic Cataclysmic Variables (mCVs), non-magnetic Cataclysmic Variables (non-mCVs), and coronally Active Binaries (ABs). For the study of the origin of the GCXE, GBXE, and GRXE, the spectral analysis is focused on equivalent widths of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α  lines. The global spectrum of the GBXE is reproduced by a combination of the mCVs, non-mCVs, and ABs spectra. On the other hand, the GRXE spectrum shows significant data excesses at the Fe i-K α and Fe xxv-He α  line energies. This means that additional components other than mCVs, non-mCVs, and ABs are required, which have symbiotic phenomena of cold gas and very high-temperature plasma. The GCXE spectrum shows larger excesses than those found in the GRXE spectrum at all the K-shell lines of iron and nickel. Among them the largest ones are the Fe i-K α , Fe xxv-He α , Fe xxvi-Ly α , and Fe xxvi-Ly β  lines. Together with the fact that the scale heights of the Fe i-K α , Fe xxv-He α , and Fe xxvi-Ly α lines are similar to that of the central molecular zone (CMZ), the excess components would be related to high-energy activity in the extreme envelopment of the CMZ.

  4. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    International Nuclear Information System (INIS)

    Shapovalova, A. I.; Burenkov, A. N.; Popović, L. Č.; Kovačević, J.; Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L.; Ilić, D.; Kovačević, A.; Kollatschny, W.; Bochkarev, N. G.; León-Tavares, J.; Mercado, A.; Benítez, E.; Dultzin, D.; De la Fuente, E.

    2012-01-01

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted Hα, Hβ, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the Hβ and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F max /F min ) of Ark 564 is between 1.5 for Hα and 1.8 for the Fe II lines. The correlation between the Fe II and Hβ flux variations is of higher significance than that of Hα and Hβ (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  5. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    Energy Technology Data Exchange (ETDEWEB)

    Shapovalova, A. I.; Burenkov, A. N. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Popovic, L. C.; Kovacevic, J. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L. [Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51-216, 72000 Puebla (Mexico); Ilic, D.; Kovacevic, A. [Isaac Newton Institute of Chile, Yugoslavia Branch, Belgrade (Serbia); Kollatschny, W. [Institut fuer Astrophysik, Georg-August-Universitaet, Goettingen (Germany); Bochkarev, N. G. [Sternberg Astronomical Institute, Moscow (Russian Federation); Leon-Tavares, J. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Mercado, A. [Universidad Politecnica de Baja California, Av. de la Industria 291, 21010 Mexicali, B.C. (Mexico); Benitez, E.; Dultzin, D. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, Mexico, D.F. 04510 (Mexico); De la Fuente, E., E-mail: ashap@sao.ru [Instituto de Astronomia y Meteorologia, Dpto. de Fisica CUCEI, Universidad de Guadalajara, Av. Vallarta 2602, 44130 Guadalajara, Jalisco (Mexico)

    2012-09-15

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted H{alpha}, H{beta}, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the H{beta} and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F{sub max}/F{sub min}) of Ark 564 is between 1.5 for H{alpha} and 1.8 for the Fe II lines. The correlation between the Fe II and H{beta} flux variations is of higher significance than that of H{alpha} and H{beta} (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  6. Multiepoch Spectropolarimetry of SN 2011fe

    International Nuclear Information System (INIS)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M.; Porter, Amber; Leising, Mark D.

    2017-01-01

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  7. Multiepoch Spectropolarimetry of SN 2011fe

    Energy Technology Data Exchange (ETDEWEB)

    Milne, Peter A.; Williams, G. Grant; Smith, Paul S.; Smith, Nathan; Jannuzi, Buell T.; Green, E. M. [University of Arizona, Steward Observatory, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Porter, Amber; Leising, Mark D. [118 Kinard Laboratory, Clemson University, Clemson, SC 29634 (United States)

    2017-01-20

    We present multiple spectropolarimetric observations of the nearby Type Ia supernova (SN) 2011fe in M101, obtained before, during, and after the time of maximum apparent visual brightness. The excellent time coverage of our spectropolarimetry has allowed better monitoring of the evolution of polarization features than is typical, which has allowed us new insight into the nature of normal SNe Ia. SN 2011fe exhibits time-dependent polarization in both the continuum and strong absorption lines. At early epochs, red wavelengths exhibit a degree of continuum polarization of up to 0.4%, likely indicative of a mild asymmetry in the electron-scattering photosphere. This behavior is more common in subluminous SNe Ia than in normal events, such as SN 2011fe. The degree of polarization across a collection of absorption lines varies dramatically from epoch to epoch. During the earliest epoch, a λ 4600–5000 Å complex of absorption lines shows enhanced polarization at a different position angle than the continuum. We explore the origin of these features, presenting a few possible interpretations, without arriving at a single favored ion. During two epochs near maximum, the dominant polarization feature is associated with the Si ii λ 6355 Å absorption line. This is common for SNe Ia, but for SN 2011fe the polarization of this feature increases after maximum light, whereas for other SNe Ia, that polarization feature was strongest before maximum light.

  8. Investigation of the dynamic NMR frequency shift for Fe57 in FeBO3

    International Nuclear Information System (INIS)

    Bun'kov, Yu.M.; Punkkinen, M.; Yulinen, E.E.

    1978-01-01

    NMR of Fe 57 in FeBO 3 is investigated by pulsed magnetic resonance techniques in the 2 to 70 K temperature range. A dynamic NMR frequency shift is observed which is due to coupling between the NMR oscillations and the low-frequency AFMR mode, the magnitude of which only slightly exceeds the micro-inhomogeneous broadening of the NMR line caused by the spread of the value of hyperfine field at the nuclei. Under these conditions the nuclear spin system possesses a number of unusual properties. Thus, broadening of the magnetic resonance line is uniform, the magnitude of the homogeneous broadening depends on the angle of deviation of the nuclear magnetization from the equilibrium axis, and an echo signal is detected which is similar to the ''solid echo'' in substances with dipole broadening of the magnetic resonance line

  9. THE SPECTRUM OF Fe II

    Energy Technology Data Exchange (ETDEWEB)

    Nave, Gillian [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States); Johansson, Sveneric, E-mail: gillian.nave@nist.gov [Lund Observatory, University of Lund, Box 43, SE-22100 Lund (Sweden)

    2013-01-15

    The spectrum of singly ionized iron (Fe II) has been recorded using high-resolution Fourier transform (FT) and grating spectroscopy over the wavelength range 900 A to 5.5 {mu}m. The spectra were observed in high-current continuous and pulsed hollow cathode discharges using FT spectrometers at the Kitt Peak National Observatory, Tucson, AZ and Imperial College, London and with the 10.7 m Normal Incidence Spectrograph at the National Institute of Standards and Technology. Roughly 12,900 lines were classified using 1027 energy levels of Fe II that were optimized to measured wavenumbers. The wavenumber uncertainties of lines in the FT spectra range from 10{sup -4} cm{sup -1} for strong lines around 4 {mu}m to 0.05 cm{sup -1} for weaker lines around 1500 A. The wavelength uncertainty of lines in the grating spectra is 0.005 A. The ionization energy of (130,655.4 {+-} 0.4) cm{sup -1} was estimated from the 3d{sup 6}({sup 5}D)5g and 3d{sup 6}({sup 5}D)6h levels.

  10. Broadband strip-line ferromagnetic resonance spectroscopy of soft magnetic CoFeTaZr patterned thin films

    Science.gov (United States)

    Gupta, S.; Kumar, D.; Jin, T. L.; Nongjai, R.; Asokan, K.; Ghosh, A.; Aparnadevi, M.; Suri, P.; Piramanayagam, S. N.

    2018-05-01

    In this paper, magnetic and magnetization dynamic properties of compositionally patterned Co46Fe40Ta9Zr5 thin films are investigated. A combination of self-assembly and ion-implantation was employed to locally alter the composition of Co46Fe40Ta9Zr5 thin film in a periodic manner. 20 keV O+ and 60 keV N+ ions were implanted at different doses in order to modify the magnetization dynamic properties of the samples in a controlled fashion. Magnetic hysteresis loop measurements revealed significant changes in the coercivity for higher influences of 5 × 1016 ions per cm2. In particular, N+ implantation was observed to induce two phase formation with high and low coercivities. Broadband strip-line ferromagnetic resonance spectroscopy over wide range of frequency (8 - 20 GHz) was used to study the magnetization dynamics as a function of ion-beam dosage. With higher fluences, damping constant showed a continuous increase from 0.0103 to 0.0430. Such control of magnetic properties at nano-scale using this method is believed to be useful for spintronics and microwave device applications.

  11. NEW Fe IX LINE IDENTIFICATIONS USING SOLAR AND HELIOSPHERIC OBSERVATORY/SOLAR ULTRAVIOLET MEASUREMENT OF EMITTED RADIATION AND HINODE/EIS JOINT OBSERVATIONS OF THE QUIET SUN

    International Nuclear Information System (INIS)

    Landi, E.; Young, P. R.

    2009-01-01

    In this work, we study joint observations of Hinode/EUV Imaging Spectrometer (EIS) and Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation of Fe IX lines emitted by the same level of the high energy configuration 3s 2 3p 5 4p. The intensity ratios of these lines are dependent on atomic physics parameters only and not on the physical parameters of the emitting plasma, so that they are excellent tools to verify the relative intensity calibration of high-resolution spectrometers that work in the 170-200 A and 700-850 A wavelength ranges. We carry out extensive atomic physics calculations to improve the accuracy of the predicted intensity ratio, and compare the results with simultaneous EIS-SUMER observations of an off-disk quiet Sun region. We were able to identify two ultraviolet lines in the SUMER spectrum that are emitted by the same level that emits one bright line in the EIS wavelength range. Comparison between predicted and measured intensity ratios, wavelengths and energy separation of Fe IX levels confirms the identifications we make. Blending and calibration uncertainties are discussed. The results of this work are important for cross-calibrating EIS and SUMER, as well as future instrumentation.

  12. Diffusion in ordered Fe-Si alloys

    International Nuclear Information System (INIS)

    Sepiol, B.; Vogl, G.

    1995-01-01

    The measurement of the diffusional Moessbauer line broadening in single crystalline samples at high temperatures provides microscopic information about atomic jumps. We can separate jumps of iron atoms between the various sublattices of Fe-Si intermetallic alloys (D0 3 structure) and measure their frequencies. The diffusion of iron in Fe-Si samples with Fe concentrations between 75 and 82 at% shows a drastic composition dependence: the jump frequency and the proportion between jumps on Fe sublattices and into antistructure (Si) sublattice positions change greatly. Close to Fe 3 Si stoichiometry iron diffusion is extremely fast and jumps are performed exclusively between the three Fe sublattices. The change in the diffusion process when changing the alloy composition from stoichiometric Fe 3 Si to the iron-rich side is discussed. (orig.)

  13. Excitation of spin waves in BiFeO3 multiferroic film by the slot line transducer

    Science.gov (United States)

    Korneev, V. I.; Popkov, A. F.; Solov'yov, S. V.

    2018-01-01

    Analysis of the efficiency of magnetoelectric excitation of spin-waves in BiFeO3 multiferroic films by a slot line is performed based on the solution of dynamic Ginzburg-Landau equations for the antiferromagnetic vector. The excitation efficiency is determined by the magnitude of the conversion coefficient of the electromagnetic wave to the spin wave by the slot line transducer or in other words, losses on conversion in the slot line. Calculations are made for a homogeneous antiferromagnetic state of the multiferroic in the presence of a sufficiently large magnetic field and for a spatially modulated spin state (SMSS) at zero magnetic field. It is shown that in the case of a homogeneous antiferromagnetic state, the losses on the excitation of spin waves exceed the excitation efficiency in the SMSS state; however, as the frequency approaches the spin excitation gap, it falls and becomes lower than in the SMSS state. Spin wave excitation in the presence of antiferromagnetic cycloid strongly depends on the relation of the slot width of the transducer to the cycloid periodicity and on the magnitude of the shift of the position of the transducer along the cycloid on its period. The usage of multiferroics for delay lines in the considered frequency range from 100 to 600 GHz requires significant reduction in conversion and propagation losses. More promising seems multiferroic usage in phase shifters and switches for this range.

  14. Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Frank

    2009-07-07

    In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

  15. El XIV Congreso Geológico Internacional de 1926 en España

    OpenAIRE

    Ayala Carcedo, Francisco Javier; Perejón, Antonio; Puche Riart, Octavio; Jordá Bordehore, Luis

    2005-01-01

    El XIV Congreso Geológico Internacional de 1926 ha sido el único organizado en España. Se exponen las características principales del mismo, a nivel temático y organizativo. Se analizan cuantitativamente el número de asistentes, las lenguas utilizadas, los países representados, las publicaciones, los autores y su productividad. Se muestra así el significado del congreso en la historia de los mismos, el predominio de geólogos franceses y alemanes, el predominio del trabajo individual y el limi...

  16. [The disgrace of Antoine Daquin, first physician of Louis XIV (1693)].

    Science.gov (United States)

    Peumery, J J

    1996-12-01

    Antoine Daquin, Principal Physician of Louis XIV and Earl of Jouy-en-Josas, was born in Paris. He was the son of Louis-Henri Daquin, Physician to Queen Marie de Médicis; his paternal grandfather, born in the Jewish religion, became converted to catholicism at Aquino, in Italy, whence his name d'Aquin, then Daquin. A. Daquin studied to be a doctor at Montpellier and graduated on 18 May 1648. He married Marguerite Gayant, Antoine Vallot's niece, Antoine Vallot being the Principal Physician of Louis XIV. This relationship permitted him to get the position of Principal Physician of the Queen, then, after Vallot's death, to succeed him, on 18 April 1672, as Principal Physician of the King. The kindliness of the King's mistress, Mme de Montespan, helped him in that appointment. Daquin was a good doctor, he turned out awkward: "great courtier, but rich, miser, grasping, wanting to establish his family anyway" said the Duc de Saint-Simon. He dared ask the King for the Archbishopric of Tours for his son: "it was the rock on which he broke up" said again Saint-Simon. On 2 November 1693, the comte de Pontchartrain came to his home by order of the King, to tell him, he was ordered to retire from Court without delay. It was forbidden him to come back or to write to the King. Guy-Crescent Fagon was designated "Premier Médecin" instead of him; but Fagon had worked at the undoing of Daquin, with a view to robbing him of his position, with the complicity of the King's new mistress, Mme de Maintenon. After his disgrace, Daquin retired probably to Moulins; he died obscurely in Vichy, on 17 May 1696. Today, Daquin is regarded as a victim of intrigues of Court, which explains his celebrity.

  17. Optical emission line spectra of Seyfert galaxies and radio galaxies

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1978-01-01

    Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from [O I] and [N I] through [Ne V] and [Fe VII] to [Fe X]. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger [O III] and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission. (Auth.)

  18. Explosive Chromospheric Evaporation and Warm Rain in a GOES C3 Flare Observed by IRIS, Hinode/EIS, and RHESSI

    Science.gov (United States)

    Brosius, J. W.; Inglis, A. R.

    2017-12-01

    IRIS and Hinode/EIS observed a C3.1 flare in AR 12002 in stare mode on 2014 March 15.GOES observed the flare to start at 00:21:35 UT and peak at 00:26:30 UT. The IRIS slitwas pointed near the center of the flare while the EIS slit was pointed 35 arcsec westof the IRIS slit. About 4 minutes before the GOES flare start, the C II and Si IV lineintensities observed by IRIS became (and remained) significantly greater than theirpre-flare average values; this indicates that the flare had begun and that thechromosphere and transition region were involved. IRIS first detected significant,blueshifted Fe XXI emission at 00:22:42 UT, by which time the C II and Si IV lineintensities had increased by factors around 100 and their profiles were significantlyredshifted. This combination of simultaneous, cospatial blueshifted Fe XXI emissionwith redshifted C II and Si IV emission indicates explosive chromospheric evaporation.SDO's HMI observed a localized area of enhanced magnetic field strength toward thesouthernmost portion of the EIS slit's position that appears to be connected to theflare site by faint loops evident in AIA 131 A emission. EIS spectra at this locationreveal intensity enhancements by factors up to about 1.7 in the Fe XIV and Fe XVI lineemission, and the emergence of faint Fe XXIII emission that is too weak to measurevelocities. Emission lines from the two coronal ions show redshifts of about 9 km/saround 00:24:00 UT. The density sensitive line intensity ratio of Fe XIV 264.7/274.2observed by EIS reveals an increase of electron density from (1.03+/-0.20)X10^9 /cm^3before the flare to (3.58+/-0.68)X10^9 /cm^3 during the flare. This combination ofredshifted coronal line emission and increased coronal electron density is consistentwith explosively evaporated flare material observed by IRIS falling as warm rain andaccumulating in the remote area observed by EIS. A thermal/nonthermal fit to the hardX-ray spectrum observed by RHESSI yields a nonthermal energy injection

  19. 3D-FE Modeling of 316 SS under Strain-Controlled Fatigue Loading and CFD Simulation of PWR Surge Line

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish [Argonne National Lab. (ANL), Argonne, IL (United States); Barua, Bipul [Argonne National Lab. (ANL), Argonne, IL (United States); Listwan, Joseph [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-03-01

    In financial year 2017, we are focusing on developing a mechanistic fatigue model of surge line pipes for pressurized water reactors (PWRs). To that end, we plan to perform the following tasks: (1) conduct stress- and strain-controlled fatigue testing of surge-line base metal such as 316 stainless steel (SS) under constant, variable, and random fatigue loading, (2) develop cyclic plasticity material models of 316 SS, (3) develop one-dimensional (1D) analytical or closed-form model to validate the material models and to understand the mechanics associated with 316 SS cyclic hardening and/or softening, (4) develop three-dimensional (3D) finite element (FE) models with implementation of evolutionary cyclic plasticity, and (5) develop computational fluid dynamics (CFD) model for thermal stratification, thermal-mechanical stress, and fatigue of example reactor components, such as a PWR surge line under plant heat-up, cool-down, and normal operation with/without grid-load-following. This semi-annual progress report presents the work completed on the above tasks for a 316 SS laboratory-scale specimen subjected to strain-controlled cyclic loading with constant, variable, and random amplitude. This is the first time that the accurate 3D-FE modeling of the specimen for its entire fatigue life, including the hardening and softening behavior, has been achieved. We anticipate that this work will pave the way for the development of a fully mechanistic-computer model that can be used for fatigue evaluation of safety-critical metallic components, which are traditionally evaluated by heavy reliance on time-consuming and costly test-based approaches. This basic research will not only help the nuclear reactor industry for fatigue evaluation of reactor components in a cost effective and less time-consuming way, but will also help other safety-related industries, such as aerospace, which is heavily dependent on test-based approaches, where a single full-scale fatigue test can cost

  20. Electron impact excitation of Fe-peak elements: forbidden transitions in the 3d5 manifold of Fe IV

    International Nuclear Information System (INIS)

    McLaughlin, B M; Hibbert, A; Scott, M P; Noble, C J; Burke, V M; Burke, P G

    2005-01-01

    Electron-impact excitation collision strengths of the Fe-peak element Fe IV are calculated in the close-coupling approximation using the R-matrix suite of codes PRMAT designed for parallel processors. One hundred and eight LS-coupled states arising from the 3d 5 , 3d 4 4s and 3d 4 4p configurations of Fe IV, are retained in the present calculations. Detailed multi-configuration interaction target wavefunctions are used with the aid of 3p 2 → 3d 2 electron promotions and a 4dbar correlation orbital in the present calculations. Effective collision strengths for optically forbidden transitions, which are extremely important in the analysis of lines in the Fe IV spectra, are obtained by averaging the electron collision strengths for a wide range of incident electron energies, over a Maxwellian distribution of velocities. Results are presented for electron temperatures (T e in Kelvin) in the range 3.3 ≤ Log T e ≤ 6.0 applicable to many laboratory and astrophysical plasmas for transitions within the 3d 5 manifold. The present results compared to previous investigations provide improved results for important lines in the Fe IV spectrum

  1. Fine-structure energy levels and radiative lifetime in Mo XIV

    International Nuclear Information System (INIS)

    Wang Xiaodong; Pei Dong; Jiang Renbin; Wang Wanjue

    2002-01-01

    Energy levels, radiative lifetime and various transition parameters for allowed transitions among the 1508 fine-structure levels belong to the (1s 2 2s 2 2p 6 3s 2 3p 6 ) 3d 10 4l, 3d 9 4l 2 , 3d 10 5l, 3d 9 4l4m, 3d 10 6l, 3d 10 7l and so on configurations of the Cu-like ions Mo XIV have been calculated by using the expanded fully relativistic GRASP code. The results are compared with those available in the literature, and the accuracy of the present data is assessed. Energy levels are expected to be accurate to within 0.81%. The authors have found some long lifetime levels

  2. 17. X avati XIV rahvusvaheline Tallinna graafikatriennaal, seekord ülddeviisi "Poliitiline/Poeetiline" all / Eve Kask

    Index Scriptorium Estoniae

    Kask, Eve

    2007-01-01

    Tallinna XIV graafikatriennaalist (Anders Kreugeri koostatud näitus "1987. Baltimaade graafika ja plakatid nõukogude aja viimasest kümnendist" ja põhinäitus "Poliitiline/Poeetiline" Kumu Kunstimuuseumis, Anders Härmi kuraatorinäitus "Poliitiline/Poeetiline" Tallinna Kunstihoones ja selle galeriis, Egle Kuckaite isikunäitus Tallinna Linnagaleriis, triennaali paneel Kadrioru Kunstimuuseumis). Triennaali peaauhinna sai Oscar Munos. Triennaaliga samaaegselt Tallinnas toimuvast rahvusvahelisest graafikakonverentsist "Impact 5" teemal "Lõigatud aeg", mille raames on avatud graafikanäitused

  3. L'escriptura i el llibre a la Catalunya Central als segles XIII i XIV

    OpenAIRE

    Torras i Cortina, Miquel

    2004-01-01

    Consultable des del TDX Títol obtingut de la portada digitalitzada Aquesta investigació reconstrueix la vida cultural de la ciutat de Manresa, a la Catalunya Central, al llarg dels segles XIII i XIV, amb el còdex baixmedieval com a fil conductor. L'estudi es basa en l'anàlisi de 305 documents amb mencions libràries (editats conjuntament), pràcticament tots ells inèdits, que procedeixen d'un buidatge exhaustiu dels fons notarials que custodien l'Arxiu Històric Comarcal de Manresa i l'Arx...

  4. [Determination of Total Iron and Fe2+ in Basalt].

    Science.gov (United States)

    Liu, Jian-xun; Chen, Mei-rong; Jian, Zheng-guo; Wu, Gang; Wu, Zhi-shen

    2015-08-01

    Basalt is the raw material of basalt fiber. The content of FeO and Fe2O3 has a great impact on the properties of basalt fibers. ICP-OES and dichromate method were used to test total Fe and Fe(2+) in basalt. Suitable instrument parameters and analysis lines of Fe were chosen for ICP-OES. The relative standard deviation (RSD) of ICP-OES is 2.2%, and the recovery is in the range of 98%~101%. The method shows simple, rapid and highly accurate for determination of total Fe and Fe(2+) in basalt. The RSD of ICP-OES and dichromate method is 0.42% and 1.4%, respectively.

  5. Clinical evaluation of neodymium-iron-boron (Ne2Fe14B) rare earth magnets in the treatment of mid line diastemas

    Science.gov (United States)

    Manoj-Kumar, Mitta; Gowri-Sankar, Singaraju; Chaitanya, Nellore; Vivek-Reddy, Ganugapanta; Venkatesh, Nettam

    2016-01-01

    Background To evaluate the closure of midline diastema using the Neodymium-Iron-Boron magnets and to compare the treatment duration of midline diastemas with the use of magnets compared to regular orthodontic treatment. Material and Methods Thirty patients with age group 12 to 30 years with the midline diastema ranging from 0.5 to 3mm were selected. These patients were divided into two groups. Diastema closure in one group was accomplished by conventional method, in other group was done with Ne2Fe14B magnets. These magnets were fitted to the labial surfaces of the maxillary central incisors such a way that the opposite poles of the magnets face each other. At each appointment, study models and radiographs were taken for study subjects and the midline diastema was measured using digital vernier calipers on the study models obtained. Descriptive statistics carried out using Paired t-test. Results Subjects treated with Ne2Fe14B magnets showed a significant difference compared to fixed orthodontic appliance subjects with respect to time of closure, rate of space closure and incisal inclination. Significant difference between 2 groups with reduction of 64.6 days in time to diastema closure in subjects treated with Ne2Fe14B magnets (Pclosure of mid line diastema in less duration of time. Key words:Midline diastema, Ne2Fe14B magnets, rare earth magnets, space closure. PMID:27034757

  6. Near-Infrared [Fe II] and H2 Study of the Galactic Supernova Remnants

    Science.gov (United States)

    Lee, Yong-Hyun; Koo, Bon-Chul; Lee, Jae-Joon; Jaffe, Daniel T.; Burton, Michael G.; Ryder, Stuart D.

    2018-01-01

    We have searched for near-infrared (NIR) [Fe II] (1.644 μm) and H2 1-0 S(1) (2.122 μm) emission features associated with Galactic supernova remnants (SNRs) using the narrow-band imaging surveys UWIFE / UWISH2 (UKIRT Widefield Infrared Survey for [Fe II] / H2). Both surveys cover about 180 square degrees of the first Galactic quadrant (7° reversal” phenomenon, i.e., the H2 emission features are detected outside the [Fe II] emission boundary. We carried out high resolution (R~40,000) NIR H- and K-band spectroscopy of the five SNRs showing the [Fe II]-H2 reversal (G11.2-0.3, KES 73, W44, 3C 396, W49B) using IGRINS (Immersion GRating INfrared Spectrograph). Various ro-vibrational H2 lines have been detected, which are used to derive the kinematic distances to the SNRs and to investigate the origin of the H2 emission. The detected H2 lines show broad line width (> 10 km s-1) and line flux ratios of thermal excitation. We discuss the origin of the extended H2 emission features beyond the the [Fe II] emission boundary.

  7. NMR measurements in milled GdCo2 and GdFe2 intermetallic compounds

    International Nuclear Information System (INIS)

    Tribuzy, C.V.B.; Guimaraes, A.P.; Biondo, A.; Larica, C.; Alves, K.M.B.

    1998-12-01

    We have used the nuclear magnetic resonance technique to study the magnetic and structural properties of the Gd-Co and Gd-Fe metallic systems, starting with the C15 laves phase intermetallic compounds, and submitting them to a high energy milling process. This leads to the amorphization of the samples, as determined by the X-ray diffraction spectra. For the Gd-Co system the NMR study used the 59 Co nucleus; in the Gd-Fe system, 155,157 Gd and 57 Fe were used. Both systems showed segregation of the pure elements, after a few hours of milling. In the Gd-Co system, a single line, of increasing width, was observed in the 59 Co spectrum. In the Gd-Fe system, the 155 Gd and 157 Gd resonances show three lines, arising from electrical quadrupole interaction. With increasing milling time, the lines broaden, and extra lines appear attributed to a cubic phase of Gd; this interpretation is supported by the X-ray analysis of the samples. The 57 Fe NMR spectrum of this system also informs on the direction of magnetization of the samples in the early stages of milling. From 1 h to 7 h of milling, a spectrum of α-Fe was observed. The study of the NMR line intensity as a function of radio frequency (r.f.) power in Gd Co 2 suggests the existence of regions of the samples with different degrees of disorder. We have observed the persistence of NMR signals from the original intermetallic compounds in the samples with up to 10 h and 7 h of milling, respectively, for Gd Co 2 and Gd Fe 2 . (author)

  8. Hyperfine field distribution of Fe83B17 glassy metal

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.

    1990-01-01

    Convolutions of Gaussian and Lorentzian lines are proposed to fit the Moessbauer spectrum of Fe 83 B 17 metallic glass. The hyperfine field distribution is constructed from three Gaussian lines corresponding to the individual line pairs. (author). 1 fig., 7 refs

  9. Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L.; Steefel, C.I.; Marcus, M.A.; Bargar, J.R.

    2010-04-01

    The readsorption of ferrous ions produced by the abiotic and microbially-mediated reductive dissolution of iron oxy-hydroxides drives a series of transformations of the host minerals. To further understand the mechanisms by which these transformations occur and their kinetics within a microporous flow environment, flow-through experiments were conducted in which capillary tubes packed with ferrihydrite-coated glass spheres were injected with inorganic Fe(II) solutions under circumneutral pH conditions at 25 C. Synchrotron X-ray diffraction was used to identify the secondary phase(s) formed and to provide data for quantitative kinetic analysis. At concentrations at and above 1.8 mM Fe(II) in the injection solution, magnetite was the only secondary phase formed (no intermediates were detected), with complete transformation following a nonlinear rate law requiring 28 hours and 150 hours of reaction at 18 and 1.8 mM Fe(II), respectively. However, when the injection solution consisted of 0.36 mM Fe(II), goethite was the predominant reaction product and formed much more slowly according to a linear rate law, while only minor magnetite was formed. When the rates are normalized based on the time to react half of the ferrihydrite on a reduced time plot, it is apparent that the 1.8 mM and 18 mM input Fe(II) experiments can be described by the same reaction mechanism, while the 0.36 input Fe(II) experiment is distinct. The analysis of the transformation kinetics suggest that the transformations involved an electron transfer reaction between the aqueous as well as sorbed Fe(II) and ferrihydrite acting as a semiconductor, rather than a simple dissolution and recrystallization mechanism. A transformation mechanism involving sorbed inner sphere Fe(II) alone is not supported, since the essentially equal coverage of sorption sites in the 18 mM and 1.8 mM Fe(II) injections cannot explain the difference in the transformation rates observed.

  10. Moessbauer study of Fe-Co nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ziyu [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou (China)]. E-mail: chenzy@lzu.edu.cn; Zhan Qingfeng; Xue Desheng; Li Fashen [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou (China); Zhou Xuezhi; Kunkel, Henry; Williams, Gwyn [Department of Physics and Astronomy, the University of Manitoba (Canada)

    2002-01-28

    Arrays of Fe{sub 1-x}Co{sub x} (0.0{<=}x{<=}0.92) nanowires have been prepared by an electrochemical process, co-depositing Fe and Co atoms into the pores of anodic aluminium; their compositions were determined by atomic absorption spectroscopy. Transmission electron microscope results show that the nanowires are regularly spaced and uniform in shape with lengths of about 7.5 {mu}m and diameters of 20 nm. The x-ray diffraction indicates a texture in the deposited nanowires. For the composition below 82 at.% cobalt, the nanowires had a body-centred-cubic structure with a [110] preferred orientation. For the 92 at.% cobalt sample, the alloy exhibited a mixture of bcc and face-centred-cubic structure. The room temperature {sup 57}Fe Moessbauer spectra of the arrays of Fe{sub 1-x}Co{sub x} nanowires have second and fifth absorption lines of the six-line pattern with almost zero intensity, indicating that the internal magnetic field in the nanowires lies along the long axis of the nanowire. The maximum values of the hyperfine field (B{sub hf} 36.6{+-}0.1 T) and isomer shift (IS=0.06{+-}0.01 mm s-1) occur for 44 at.% cobalt. The variations of the isomer shift and the linewidths with composition indicate that the Fe{sub 1-x}Co{sub x} alloy nanowires around the equiatomic composition are in an atomistic disordered state. (author)

  11. Electron density diagnostics in the 10-100 A interval for a solar flare

    Science.gov (United States)

    Brown, W. A.; Bruner, M. E.; Acton, L. W.; Mason, H. E.

    1986-01-01

    Electron density measurements from spectral-line diagnostics are reported for a solar flare on July 13, 1982, 1627 UT. The spectrogram, covering the 10-95 A interval, contained usable lines of helium-like ions C V, N VI, O VII, and Ne IX which are formed over the temperature interval 0.7-3.5 x 10 to the 6th K. In addition, spectral-line ratios of Si IX, Fe XIV, and Ca XV were compared with new theoretical estimates of their electron density sensitivity to obtain additional electron density diagnostics. An electron density of 3 x 10 to the 10th/cu cm was obtained. The comparison of these results from helium-like and other ions gives confidence in the utility of these tools for solar coronal analysis and will lead to a fuller understanding of the phenomena observed in this flare.

  12. Magnetic Properties and Microstructure of FeOx/Fe/FePt and FeOx/FePt Films

    Directory of Open Access Journals (Sweden)

    Jai-Lin Tsai

    2013-01-01

    Full Text Available The Fe(6 nm/FePt film with perpendicular magnetization was deposited on the glass substrate. To study the oxygen diffusion effect on the coupling of Fe/FePt bilayer, the plasma oxidation with 0.5~7% oxygen flow ratio was performed during sputtered part of Fe layer and formed the FeOx(3 nm/Fe(3 nm/FePt trilayer. Two-step magnetic hysteresis loops were found in trilayer with oxygen flow ratio above 1%. The magnetization in FeOx and Fe/FePt layers was decoupled. The moments in FeOx layer were first reversed and followed by coupled Fe/FePt bilayer. The trilayer was annealed again at 500°C and 800°C for 3 minutes. When the FeOx(3 nm/Fe(3 nm/FePt trilayer was annealed at 500°C, the layers structure was changed to FeOx(6 nm/FePt bilayer due to oxygen diffusion. The hard-magnetic FeOx(6 nm/FePt film was coupled with single switching field. The FeOx/(disordered FePt layer structure was observed with further annealing at 800°C and presented soft-magnetic loop. In summary, the coupling between soft-magnetic Fe, FeOx layer, and hard-magnetic L10 FePt layer can be controlled by the oxygen diffusion behavior, and the oxidation of Fe layer was tuned by the annealing temperature. The ordered L10 FePt layer was deteriorated by oxygen and became disordered FePt when the annealed temperature was up to 800°C.

  13. Electrochemical alkaline Fe(VI) water purification and remediation.

    Science.gov (United States)

    Licht, Stuart; Yu, Xingwen

    2005-10-15

    Fe(VI) is an unusual and strongly oxidizing form of iron, which provides a potentially less hazardous water-purifying agent than chlorine. A novel on-line electrochemical Fe(VI) water purification methodology is introduced. Fe(VI) addition had been a barrier to its effective use in water remediation, because solid Fe(VI) salts require complex (costly) syntheses steps and solutions of Fe(VI) decompose. Online electrochemical Fe(VI) water purification avoids these limitations, in which Fe(VI) is directly prepared in solution from an iron anode as the FeO42- ion, and is added to the contaminant stream. Added FeO42- decomposes, by oxidizing a wide range of water contaminants including sulfides (demonstrated in this study) and other sulfur-containing compounds, cyanides (demonstrated in this study), arsenic (demonstrated in this study), ammonia and other nitrogen-containing compounds (previously demonstrated), a wide range of organics (phenol demonstrated in this study), algae, and viruses (each previously demonstrated).

  14. Fe L-shell Excitation Cross Section Measurements on EBIT-I

    Science.gov (United States)

    Chen, Hui; Beiersdorfer, P.; Brown, G.; Boyce, K.; Kelley, R.; Kilbourne, C.; Porter, F.; Gu, M. F.; Kahn, S.

    2006-09-01

    We report the measurement of electron impact excitation cross sections for the strong iron L-shell 3-2 lines of Fe XVII to Fe XXIV at the LLNL EBIT-I electron beam ion trap using a crystal spectrometer and NASA-Goddard Space Flight Center's 6x6 pixel array microcalorimeter. The cross sections were determined by direct normalization to the well-established cross sections for radiative electron capture. Our results include the excitation cross section for over 50 lines at multiple electron energies. Although we have found that for 3C line in Fe XVII the measured cross sections differ significantly from theory, in most cases the measurements and theory agree within 20%. This work was performed under the auspices of the U.S. DOE by LLNL under contract No. W-7405-Eng-48 and supported by NASA APRA grants to LLNL, GSFC, and Stanford University.

  15. Origin of Magnetism in Hydrothermally Aged 2-Line Ferrihydrite Suspensions.

    Science.gov (United States)

    Cao, Liang; Jiang, Zhao-Xia; Du, Yong-Hua; Yin, Xin-Mao; Xi, Shi-Bo; Wen, Wen; Roberts, Andrew P; Wee, Andrew T S; Xiong, Yi-Min; Liu, Qing-Song; Gao, Xing-Yu

    2017-03-07

    As an iron oxyhydroxide, nanosized ferrihydrite (Fh) is important in Earth science, biology, and industrial applications. However, its basic structure and origin of its magnetism have long been debated. We integrate synchrotron-based techniques to explore the chemical structures of 2-line ferrihydrite and to determine the origin of its magnetism during hydrothermal aging in air. Our results demonstrate that both the magnetism and X-ray magnetic circular dichroism (XMCD) signal of 2-line ferrihydrite are enhanced with aging time, and that XMCD spectral patterns resemble that of maghemite (γ-Fe 2 O 3 ) rather than magnetite (Fe 3 O 4 ). Fe L-edge and K-edge X-ray absorption spectroscopy (XAS) further indicate formation of both maghemite and hematite (α-Fe 2 O 3 ) with increasing concentrations with longer hydrothermal aging time. Thus, magnetic enhancement with longer hydrothermal aging time is attributed to increasing maghemite concentration instead of a magnetically ordered ferrihydrite as previously reported. Moreover, L-edge and K-edge XAS spectra with different probing depths yield different ratios of these Fe oxides, which suggest the formation of a core (ferrihydrite-rich)-shell (with a mixture of both allotropes; α-Fe 2 O 3 and γ-Fe 2 O 3 ) structure during hydrothermal aging. Our results provide insights into the chemical evolution of 2-line ferrihydrite that reveal unambiguously the origin of its magnetism.

  16. Peculiar A star HD 43819 - A photographic region line-identification study

    International Nuclear Information System (INIS)

    Adelman, S.J.; The Citadel, Charleston, SC)

    1985-01-01

    A line identification study of the sharp-lined silicon star HD 43819 has been performed for the photographic region 3759-4924 A. Comparison of this star's spectrum with those of other silicon stars shows that it shares many of their apparent abundance anomalies. The TiII, CrII, FeI, and FeII spectra are well represented while the singly ionized rare earths are represented by at best a few lines per species. 21 references

  17. Productos vegetales utilizados en Madrid entre los siglos XIV y XIX

    Directory of Open Access Journals (Sweden)

    Menéndez de Luarca, Luis Ramón-Laca

    2005-12-01

    Full Text Available In an attempt to describe the plant culture of Madrid of the Middle Ages and Modern Age, this paper provides a list of some 300 vegetal products cited in various documents referring to the city dated to the fourteenth, sixteenth, seventeenth, eighteenth and nineteenth centuries. The identity of the 170 plants mentioned in these documents is discussed.

    Con la intención de esbozar una historia de la cultura madrileña de las plantas a lo largo de la Edad Media y la Edad Moderna, presentamos aquí una lista de aproximadamente 300 productos vegetales citados en diversos documentos de los siglos XIV, XVI, XVII, XVIII y XIX referentes a la ciudad de Madrid, incluyendo una hipótesis de identificación de las 170 especies correspondientes a dichos productos.

  18. Notarios públicos en Inglaterra en los siglos XIV y XV

    Directory of Open Access Journals (Sweden)

    Patrick Zutshi .

    2000-07-01

    Full Text Available En este artículo el profesor PatricK Zutshi, de la Universidad de Cambridge, analiza desde diversos ángulos el papel de los notarios públicos en Inglaterra durante los siglos XIV y XV, a partir de una serie de comentarios sobre el nombramiento, la formación académica, el tipo de investidura, la competencia, la organización gremial, los estatutos, etc., de las funciones notariales en contraste con las existentes en el continente. Esta reseña permite acercarse a los más complejos nexos entre las administraciones pública y la eclesiástica y a las sutiles y a veces tensas relaciones entre el imperio, el papado y los procesos de laicización de la administración en Inglaterra, anteriores al siglo XVI.

  19. XIV Mediterranean Conference on Medical and Biological Engineering and Computing

    CERN Document Server

    Christofides, Stelios; Pattichis, Constantinos

    2016-01-01

    This volume presents the proceedings of Medicon 2016, held in Paphos, Cyprus. Medicon 2016 is the XIV in the series of regional meetings of the International Federation of Medical and Biological Engineering (IFMBE) in the Mediterranean. The goal of Medicon 2016 is to provide updated information on the state of the art on Medical and Biological Engineering and Computing under the main theme “Systems Medicine for the Delivery of Better Healthcare Services”. Medical and Biological Engineering and Computing cover complementary disciplines that hold great promise for the advancement of research and development in complex medical and biological systems. Research and development in these areas are impacting the science and technology by advancing fundamental concepts in translational medicine, by helping us understand human physiology and function at multiple levels, by improving tools and techniques for the detection, prevention and treatment of disease. Medicon 2016 provides a common platform for the cross fer...

  20. Pouvoir et religion à la chapelle royale de Versailles sous Louis XIV Power and religion at the royal chapel of Versailles under Louis XIV

    Directory of Open Access Journals (Sweden)

    Alexandre Maral

    2007-12-01

    Full Text Available D’une manière peut‑être plus sensible que partout ailleurs, les objets et les insignes du pouvoir prennent une importance particulière dans le contexte du cérémonial liturgique de la religion catholique. À la chapelle royale de Versailles, la présence régulière du monarque et de sa cour complique encore la situation, d’autant que la desserte est assurée par deux corps distincts d’ecclésiastiques. Dépassant le simple cadre des préséances, Louis XIV a défini autour de sa personne royale un système rituel susceptible d’en manifester le caractère épiscopal dérivé du sacre. De même, l’enjeu juridictionnel représenté par la Chapelle royale se traduit par un jeu subtil d’attitudes, de gestes et de rites, chorégraphie sacrée qui accompagne et exprime les revendications des partisans et des adversaires de l’exemption du lieu de culte royal au regard du diocèse de Paris. Ce discours trouve un écho partiel dans le programme décoratif de la chapelle définitive du palais, achevée en 1710.Objects and symbols of power take on a particular importance in the liturgical ceremony of the Catholic Church, perhaps more so than in any other context. At the royal chapel of Versailles, the regular presence of the king and his court complicated the situation further, all the more so in that religious ceremony was administered by two distinct ecclesiastic bodies. Beyond the rules of precedence, Louis XIV had introduced around his royal persona a system of ritual that would manifest the episcopal identity conferred upon him by his coronation. Similarly, the jurisdictional authority represented by the royal chapel was conveyed in a subtle play of attitudes, gestures and rites, a symbolic choreography that accompanied and expressed the claims of the partisans and adversaries of the exemption of the royal place of worship with regard to the diocese of Paris. This stance was reflected in the decorative scheme of the palace

  1. Herziening van de zedendelicten? : Een analyse van Titel XIV, Tweede Boek, Wetboek van Strafrecht met het oog op samenhang, complexiteit en normstelling

    NARCIS (Netherlands)

    Lindenberg, Kai; van Dijk, Alwin

    2015-01-01

    De zedendelicten zoals omschreven in Titel XIV, Boek 2 van het Wetboek van Strafrecht, zijn geen rustig bezit. Sinds 1886 – en met name de laatste vijfentwintig jaar – is veel aan de zedentitel gesleuteld en toegevoegd. Diverse malen is daarbij gesproken over algehele herziening, maar uiteindelijk

  2. Herziening van de zedendelicten? : Een analyse van Titel XIV, Tweede Boek, Wetboek van Strafrecht met het oog op samenhang, complexiteit en normstelling

    NARCIS (Netherlands)

    Lindenberg, Kai; van Dijk, Alwin

    2016-01-01

    De zedendelicten zoals omschreven in Titel XIV, Boek 2 van het Wetboek van Strafrecht, zijn geen rustig bezit. Sinds 1886 – en met name de laatste vijfentwintig jaar – is veel aan de zedentitel gesleuteld en toegevoegd. Diverse malen is daarbij gesproken over algehele herziening, maar uiteindelijk

  3. Study of the reaction of astrophysical interest 60Fe(n,γ)61Fe via (d,pγ) transfer reaction

    International Nuclear Information System (INIS)

    Giron, S.

    2011-12-01

    60 Fe is of special interest in nuclear astrophysics. Indeed the recent observations of 60 Fe characteristic gamma-ray lines by the RHESSI and INTEGRAL spacecrafts allowed to measure the total flux of 60 Fe over the Galaxy. Moreover the observation in presolar grains of an excess of the daughter-nuclei of 60 Fe, 60 Ni, gives constraints on the conditions of formation of the early solar system. However, the cross-sections of some reactions involved in 60 Fe nucleosynthesis and included to stellar models are still uncertain. The destruction reaction of 60 Fe, 60 Fe(n, γ) 61 Fe, is one of them. The total cross-section can be separate into two contributions: the direct one, involving states below the neutron separation threshold of 61 Fe, and the resonant one.We improved 61 Fe spectroscopy in order to evaluate the direct capture part of the 60 Fe(n, γ) 61 Fe reaction cross-section. 60 Fe(n, γ) 61 Fe was thus studied via d( 60 Fe, pγ) 61 Fe transfer reaction with the CATS/MUST2/EXOGAM setup at LISE-GANIL. DWBA analysis of experimental proton differential cross-sections allowed to extract orbital angular momentum and spectroscopic factors of different populated states identified below the neutron threshold. A comparison of experimental results for 61 Fe with experimental results for similar nuclei and with shell-model calculations was also performed. (author) [fr

  4. Le règne de Louis XIV, ou la rupture définitive entre la société française et la monarchie

    OpenAIRE

    Bouveresse, Jacques

    2018-01-01

    Le règne de Louis XIV, comme Janus, présente deux faces. La première de ces faces qui correspond au vingt-cinq premières années du règne est brillante et lumineuse. Tout s’ordonne autour du roi dans un bel ordonnancement classique. Louis XIV est le maître de la guerre et de la paix. Il est entouré d’une cour brillante où il n’y a pas que des courtisans mais aussi beaucoup d’hommes capables et compétents. À partir des années 1680 – et à cet égard la révocation de l’Édit de Nantes en 1685 est u...

  5. Tradycje śląskiej kultury muzycznej. XIV Miȩdzynarodowa 299 Konferencja, Wrocław 2.–4. 3. 2016

    Czech Academy of Sciences Publication Activity Database

    Gabrielová, Jarmila

    2016-01-01

    Roč. 53, 2/3 (2016), s. 300-301 ISSN 0018-7003. [Tradycje śląskiej kultury muzycznej. XIV Miȩdzynarodowa Konferencja. Wrocław, 02.03.2016-04.03.2016] Institutional support: RVO:68378076 Keywords : music ological conference * Silesia * history of music Subject RIV: AL - Art, Architecture, Cultural Heritage

  6. High-Resolution X-Ray Spectra of the Symbiotic Star SS73 17

    Science.gov (United States)

    Eze, R. N. C.; Luna, G. J. M.; Smith, R. K.

    2010-01-01

    SS73 17 was an innocuous Mira-type symbiotic star until the International Gamma-Ray Astrophysics Laboratory and Swift discovered its bright hard X-ray emission, adding it to the small class of "hard X-ray emitting symbiotics." Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2.0 keV bandpass. We present here follow-up observations with the Chandra High Energy Transmission Grating and Suzaku that confirm the earlier detection of strong emission lines of Fe K(alpha) fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high-resolution spectrum also shows emission lines of other highly ionized ions as Si xiv and possibly S XVI. In addition, a re-analysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe xxv lines shows that these lines are thermal, not photoionized, in origin.With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling-flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.

  7. HIGH-RESOLUTION X-RAY SPECTRA OF THE SYMBIOTIC STAR SS73 17

    International Nuclear Information System (INIS)

    Eze, R. N. C.; Luna, G. J. M.; Smith, R. K.

    2010-01-01

    SS73 17 was an innocuous Mira-type symbiotic star until the International Gamma-Ray Astrophysics Laboratory and Swift discovered its bright hard X-ray emission, adding it to the small class of 'hard X-ray emitting symbiotics'. Suzaku observations in 2006 then showed it emits three bright iron lines as well, with little to no emission in the 0.3-2.0 keV bandpass. We present here follow-up observations with the Chandra High Energy Transmission Grating and Suzaku that confirm the earlier detection of strong emission lines of Fe Kα fluorescence, Fe XXV and Fe XXVI but also show significantly more soft X-ray emission. The high-resolution spectrum also shows emission lines of other highly ionized ions as Si XIV and possibly S XVI. In addition, a re-analysis of the 2006 Suzaku data using the latest calibration shows that the hard (15-50 keV) X-ray emission is brighter than previously thought and remains constant in both the 2006 and 2008 data. The G ratio calculated from the Fe XXV lines shows that these lines are thermal, not photoionized, in origin. With the exception of the hard X-ray emission, the spectra from both epochs can be fit using thermal radiation assuming a differential emission measure based on a cooling-flow model combined with a full and partial absorber. We show that acceptable fits can be obtained for all the data in the 1-10 keV band varying only the partial absorber. Based on the temperature and accretion rate, the thermal emission appears to be arising from the boundary layer between the accreting white dwarf and the accretion disk.

  8. Accurate projected augmented wave datasets for BaFe2As2

    International Nuclear Information System (INIS)

    Cao Chao; Wu Yuing; Hamdan, Rashid; Wang, Yunpeng; Cheng Haiping

    2010-01-01

    By carefully choosing parameters and including more semi-core orbitals as valence electrons, we have constructed a high-quality projected augmented wave dataset that yields results comparable to existing full-potential linearized augmented plane-wave calculations. The dataset was then applied to BaFe 2 As 2 to study the effects of different levels of structure optimization, as well as different choices of exchange-correlation functionals. It was found that the local density approximation exchange-correlation functional fails to find the correct spin-density-wave anti-ferromagnetic (SDW-AFM) ground state under full optimization, while the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional obtains the correct state but significantly overestimates the magnetism. The electronic structure of the SDW-AFM state is not very sensitive to structure optimizations with the PBE exchange-correlation functional because the positions of the As atoms are preserved under optimizations. We further investigated the Ba atom diffusion process on the BaFe 2 As 2 surface using the nudged elastic bands method. The Ba atom was found to be stable above the center of the squares formed by the surface As atoms, and a diffusion barrier of 1.2 eV was found. Our simulated scanning tunneling microscopy image suggests an ordered surface Ba atom structure, in agreement with Massee et al (2009 Phys. Rev. B 80 140507; van Heumen E et al 2010 arXiv:1009.3493v1).

  9. EVIDENCE FOR ULTRA-FAST OUTFLOWS IN RADIO-QUIET ACTIVE GALACTIC NUCLEI. II. DETAILED PHOTOIONIZATION MODELING OF Fe K-SHELL ABSORPTION LINES

    International Nuclear Information System (INIS)

    Tombesi, F.; Cappi, M.; Dadina, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.

    2011-01-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet active galactic nuclei (AGNs). These have been detected essentially through blueshifted Fe XXV/XXVI K-shell transitions. In the previous paper of this series we defined UFOs as those highly ionized absorbers with an outflow velocity higher than 10,000 km s –1 and assessed the statistical significance of the associated blueshifted absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. The present paper is an extension of that work. First, we report a detailed curve of growth analysis of the main Fe XXV/XXVI transitions in photoionized plasmas. Then, we estimate an average spectral energy distribution for the sample sources and directly model the Fe K absorbers in the XMM-Newton spectra with the detailed Xstar photoionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35% and that the majority of the Fe K absorbers are indeed associated with UFOs. The outflow velocity distribution spans from ∼10,000 km s –1 (∼0.03c) up to ∼100,000 km s –1 (∼0.3c), with a peak and mean value of ∼42,000 km s –1 (∼0.14c). The ionization parameter is very high and in the range log ξ ∼ 3-6 erg s –1 cm, with a mean value of log ξ ∼ 4.2 erg s –1 cm. The associated column densities are also large, in the range N H ∼ 10 22 -10 24 cm –2 , with a mean value of N H ∼ 10 23 cm –2 . We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7 keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton-thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected

  10. El Abad del Monasterio de Poblet como Limosnero Real y su rendición de cuentas (S. XIV

    Directory of Open Access Journals (Sweden)

    Ricard Monclús Guitart

    2006-07-01

    real –privilegios y obligaciones–, y lo que para nosotros ha sido más importante, los documentos que toda su administración conllevaba, así como conocer el proceso sobre el que se sustentaba la rendición de las cuentas de la limosna real, y como se produce un endurecimiento en el control de los registros a medida que nos acercamos a las postrimerías del siglo XIV.

  11. An X-ray survey of the central molecular zone: Variability of the Fe Kα emission line

    Science.gov (United States)

    Terrier, R.; Clavel, M.; Soldi, S.; Goldwurm, A.; Ponti, G.; Morris, M. R.; Chuard, D.

    2018-05-01

    There is now abundant evidence that the luminosity of the Galactic super-massive black hole (SMBH) has not always been as low as it is nowadays. The observation of varying non-thermal diffuse X-ray emission in molecular complexes in the central 300 pc has been interpreted as delayed reflection of a past illumination by bright outbursts of the SMBH. The observation of different variability timescales of the reflected emission in the Sgr A molecular complex can be well explained if the X-ray emission of at least two distinct and relatively short events (i.e. about 10 yr or less) is currently propagating through the region. The number of such events or the presence of a long-duration illumination are open questions. Variability of the reflected emission all over of the central 300 pc, in particular in the 6.4 keV Feline, can bring strong constraints. To do so we performed a deep scan of the inner 300 pc with XMM-Newton in 2012. Together with all the archive data taken over the course of the mission, and in particular a similar albeit more shallow scan performed in 2000-2001, this allows for a detailed study of variability of the 6.4 keV line emission in the region, which we present here. We show that the overall 6.4 keV emission does not strongly vary on average, but variations are very pronounced on smaller scales. In particular, most regions showing bright reflection emission in 2000-2001 significantly decrease by 2012. We discuss those regions and present newly illuminated features. The absence of bright steady emission argues against the presence of an echo from an event of multi-centennial duration and most, if not all, of the emission can likely be explained by a limited number of relatively short (i.e. up to 10 yr) events. Images of the Fe Kα emission as FITS files are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A102

  12. Constraining Line-of-sight Confusion in the Corona Using Linearly Polarized Observations of the Infrared FeXIII 1075nm and SiX 1430nm Emission Lines

    Science.gov (United States)

    Dima, G. I.; Kuhn, J. R.; Berdyugina, S.

    2017-12-01

    Measurements of the coronal magnetic field are difficult because of the intrinsically faint emission of coronal plasma and the large spurious background due to the bright solar disk. This work addresses the problem of resolving the confusion of the line-of-sight (LOS) integration through the optically-thin corona being observed. Work on developing new measuring techniques based on single-point inversions using the Hanle effect has already been described (Dima et al. 2016). It is important to develop a technique to assess when the LOS confusion makes comparing models and observations problematic. Using forward integration of synthetic emission through magnetohydrodynamic (MHD) models together with simultaneous linearly polarized observations of the FeXIII 1075nm and SiX 1430nm emission lines allows us to assess LOS confusion. Since the lines are both in the Hanle saturated regime their polarization angles are expected to be aligned as long as the gas is sampling the same magnetic field. If significant contributions to the emission is taking place from different regions along the LOS due to the additive nature of the polarized brightness the measured linear polarization between the two lines will be offset. The size of the resolution element is important for this determination since observing larger coronal regions will confuse the variation along the LOS with that in the plane-of-sky. We also present comparisons between synthetic linearly polarized emission through a global MHD model and observations of the same regions obtained using the 0.5m Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC) telescope located on Haleakala, Maui. This work is being done in preparation for the type of observations that will become possible when the next generation 4m DKIST telescope comes online in 2020.

  13. Characterisation of sub-micrometre features with the FE-EPMA

    Science.gov (United States)

    McSwiggen, P.

    2014-03-01

    The goal of this work is to compare two strategies for doing sub-micrometre analyses using the Fe-Ni binary system, as an example. The first approach involves reducing the overvoltage to 1 - 3 kV over the critical ionisation energy of the K X-ray lines. Using such a small overvoltage greatly restricts the size of the analytical volume. Upon entering the sample, the beam electrons quickly lose the additional energy required to excite the X-rays of interest. As a result, the K X-ray line for Fe and Ni will only be produced very near the surface. The second strategy is to use the L-lines for Fe and Ni, and drop the accelerating voltage to a level that will produce the smallest overall interaction volume of the beam electrons. Each strategy has its advantages and disadvantages that depend on the ultimate goal of the analysis and the elements involved. Both methods produce small analytical volumes. However, the L-lines from the transition elements are more problematic because of uncertainties with their mass absorption coefficients. Therefore, using the L-lines in low-kV analyses are more challenging to get good quantitative results. The advantage of using L-lines is that they travel a shorter distance within the sample, and therefore secondary fluorescence becomes less of an issue. The best results will come from a combination of these strategies. Using a multiple kV approach allows the user to select the optimum conditions for each element.

  14. Analyais of solar X-ray emission line profiles

    International Nuclear Information System (INIS)

    Burek, A.J.; Marrus, D.M.; Blake, R.L.; Fenimore, E.E.

    1981-01-01

    We report results of the analysis of the X-ray emission line profiles for the Ne X La and Fe XVII 4d 1 P 1 lines produced in an active region that was undergoing a radio and X-ray gradual rise and fall (GRF) in intensity. The spectra were obtained with collimated Bragg spectrometers launched on a rocket from White Sands Missile Range on 1976 March 26. Using a crystal of ammonium acid phthalate, we have fully resolved the Ne X La and Fe XVII 4d 1 P 1 lines, permitting an accurate determinination of the Ne X La intensity and allowing Doppler broadened profiles for lines formed from ions having greatly different atomic mass and charge to be measured. An isothermal model derived from the Ne IX/Ne X resonance line intensity ratio gives an electron temperature of 3.4 x 10 6 K. An isothermal model, however, fails to account for the intensities of all lines and continuum observed. All multitemperature models that do reproduce the observed relative line intensities require the presence of a hot plasma component with an electron temperature in excess of 5 x 10 6 K. The presence of a high temperature component is also suggested by the measured line to continuum ratio of 3.6 in the 12--15 A wavelength interval. Interpretation of the line profiles in terms of a multitemperature model requires an rms turbulence velocity of 48 +- 15 km s -1 for Fe XVII 1 P 1 and 74 +- 54 km s - 2exclamation for Ne X La at the 95% confidence level. Collimated scans across the active region show the presence of a compact source of intense X-ray emission close to the magnetic neutral line, which is very probably the GRF plasma

  15. A Survey of X-Ray Variability in Seyfert 1 Galaxies with XMM-Newton to study the soft excess and the broad Fe lines

    Science.gov (United States)

    Ponti, Gabriele

    The nature of the soft excess and the presence of the broad Fe lines is still nowadays highly debated because the different absorption/emission models are degenerate. Spectral variability studies have the potential to break this degeneracy. I will present the results of a spectral variability RMS survey of the 36 brightest type 1 Seyfert galaxies observed by XMM-Newton for more than 30 ks. More than 80 as already measured, on longer timescales, with RXTE (Markowitz et al. 2004). About half of the sample show lower variability in the soft energy band, indicating that the emission from the soft excess is more stable than the one of the continuum. While the other sources show a soft excess that is as variable as the continuum. About half of the sample do not show an excess of variability where the warm absorber component imprints its stronger features, suggesting that for these sources the soft excess is not produced by a relativistic absorbing wind. In a few bright and well exposed sources it has been possible to measure an excess of variability at the energy of the broad component of the Fe K line, in agreement with the broad emission line interpretation. For the sources where more than one observation was available the stability of the shape of the RMS spectrum has been investigated. Moreover, it will be presented the results of the computation of the excess variance of all the radio quiet type 1 AGN of the XMM-Newton database. The relations between variability, black hole mass, accretion rate and luminosity are investigated and their scatter measured.

  16. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Science.gov (United States)

    Rakshit, Suvendu; Stalin, C. S.

    2017-06-01

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z anti-correlated with Fe II strength but correlated with the width of the Hβ line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  17. Evidence for Ultra-Fast Outflows in Radio-Quiet AGNs. 2; Detailed Photoionization Modeling of Fe K-Shell Absorption Lines

    Science.gov (United States)

    Tombesi, Francesco; Clapp, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.; Dadina, M.

    2011-01-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher than 10,000km/s and assessed the statistical significance of the associated blue shifted FeK absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. In the present paper we report a detailed curve of growth analysis and directly model the FeK absorbers with the Xstar photo-ionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35%. The outflow velocity distribution spans from \\sim10,000km/s (\\sim0.03c) up to \\siml00,000kmis (\\sim0.3c), with a peak and mean value of\\sim42,000km/s (\\sim0.14c). The ionization parameter is very high and in the range log\\xi 3-6 erg s/cm, with a mean value of log\\xi 4.2 erg s/cm. The associated column densities are also large, in the range N_H\\siml0(exp 22)-10(exp 24)/sq cm, with a mean value of N_H\\siml0(exp23)/sq cm. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected cosmological feedback from AGNs and their study can provide important clues on the connection between accretion disks, winds and jets.

  18. Local hydrated structure of an Fe2+/Fe3+ aqueous solution: an investigation using a combination of molecular dynamics and X-ray absorption fine structure methods

    International Nuclear Information System (INIS)

    Ye Qing; Zhou Jing; Zhao Haifeng; Chen Xing; Chu Wangsheng; Zheng Xusheng; Marcelli, Augusto; Wu Ziyu

    2013-01-01

    The hydrated shell of both Fe 2+ and Fe 3+ aqueous solutions are investigated by using the molecular dynamics (MD) and X-ray absorption structure (XAS) methods. The MD simulations show that the first hydrated shells of both Fe 2+ and Fe 3+ are characterized by a regular octahedron with an Fe-O distance of 2.08Å for Fe 2+ and 1.96Å for Fe 3+ , and rule out the occurrence of a Jahn-Teller distortion in the hydrated shell of an Fe 2+ aqueous solution. The corresponding X-ray absorption near edge fine structure (XANES) calculation successfully reproduces all features in the XANES spectra in Fe 2+ and Fe 3+ aqueous solution. A feature that is located at energy 1 eV higher than the white line (WL) in an Fe 3+ aqueous solution may be assigned to the contribution of the charge transfer. (authors)

  19. Unshifted Metastable He I* Mini-broad Absorption Line System in the Narrow-line Type 1 Quasar SDSS J080248.18+551328.9

    Science.gov (United States)

    Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Ge, Jian; Wang, Huiyuan; Komossa, S.; Hamann, Fred; Zuther, Jens; Liu, Wenjuan; Lu, Honglin; Zuo, Wenwen; Yang, Chenwei; Yuan, Weimin

    2015-02-01

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ~ 1500 km s-1 centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n H ~ (1.0-2.5) × 105 cm-3 and a column density of N H ~ (1.0-3.2) × 1021 cm-2 and is located at R ~100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

  20. Temperature dependence of the magnetic excitation spectrum of Dy2Fe14B

    International Nuclear Information System (INIS)

    Loewenhaupt, M.; Fabi, P.; Sosnowska, I.; Frick, B.; Eccleston, R.

    1995-01-01

    We present inelastic magnetic neutron scattering spectra of polycrystalline Dy 2 Fe 14 B measured between 2 and 650 K employing different time-of-flight spectrometers. At the lowest temperatures we can identify in the magnetic excitation spectra the following features: (i) a dominant line at Δ=12 meV with a shoulder at 11.1 meV, and (ii) two weak lines at 3.8 and 5.5 meV. The temperature dependence of the average position Δ of the dominant line follows roughly the temperature dependence of the spontaneous magnetization of Y 2 Fe 14 B indicating that the energy of this mode is substantially fixed by the molecular fields of the surrounding Fe moments. Slight deviations, however, indicate that the Dy level spacing is not equidistant due to crystal field effects. ((orig.))

  1. Spectroscopic Diagnostics of Solar Magnetic Flux Ropes Using Iron Forbidden Line

    Science.gov (United States)

    Cheng, X.; Ding, M. D.

    2016-05-01

    In this Letter, we present Interface Region Imaging Spectrograph Fe xxi 1354.08 Å forbidden line emission of two magnetic flux ropes (MFRs) that caused two fast coronal mass ejections with velocities of ≥1000 km s-1 and strong flares (X1.6 and M6.5) on 2014 September 10 and 2015 June 22, respectively. The extreme-ultraviolet images at the 131 and 94 Å passbands provided by the Atmospheric Imaging Assembly on board Solar Dynamics Observatory reveal that both MFRs initially appear as suspended hot channel-like structures. Interestingly, part of the MFRs is also visible in the Fe xxi 1354.08 forbidden line, even prior to the eruption, e.g., for the SOL2014-09-10 event. However, the line emission is very weak and that only appears at a few locations but not the whole structure of the MFRs. This implies that the MFRs could be comprised of different threads with different temperatures and densities, based on the fact that the formation of the Fe xxi forbidden line requires a critical temperature (˜11.5 MK) and density. Moreover, the line shows a non-thermal broadening and a blueshift in the early phase. It suggests that magnetic reconnection at that time has initiated; it not only heats the MFR and, at the same time, produces a non-thermal broadening of the Fe xxi line but also produces the poloidal flux, leading to the ascension of the MFRs.

  2. SPECTROSCOPIC DIAGNOSTICS OF SOLAR MAGNETIC FLUX ROPES USING IRON FORBIDDEN LINE

    International Nuclear Information System (INIS)

    Cheng, X.; Ding, M. D.

    2016-01-01

    In this Letter, we present Interface Region Imaging Spectrograph Fe xxi 1354.08 Å forbidden line emission of two magnetic flux ropes (MFRs) that caused two fast coronal mass ejections with velocities of ≥1000 km s"−"1 and strong flares (X1.6 and M6.5) on 2014 September 10 and 2015 June 22, respectively. The extreme-ultraviolet images at the 131 and 94 Å passbands provided by the Atmospheric Imaging Assembly on board Solar Dynamics Observatory reveal that both MFRs initially appear as suspended hot channel-like structures. Interestingly, part of the MFRs is also visible in the Fe xxi 1354.08 forbidden line, even prior to the eruption, e.g., for the SOL2014-09-10 event. However, the line emission is very weak and that only appears at a few locations but not the whole structure of the MFRs. This implies that the MFRs could be comprised of different threads with different temperatures and densities, based on the fact that the formation of the Fe xxi forbidden line requires a critical temperature (∼11.5 MK) and density. Moreover, the line shows a non-thermal broadening and a blueshift in the early phase. It suggests that magnetic reconnection at that time has initiated; it not only heats the MFR and, at the same time, produces a non-thermal broadening of the Fe xxi line but also produces the poloidal flux, leading to the ascension of the MFRs.

  3. SPECTROSCOPIC DIAGNOSTICS OF SOLAR MAGNETIC FLUX ROPES USING IRON FORBIDDEN LINE

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, X.; Ding, M. D., E-mail: xincheng@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2016-05-20

    In this Letter, we present Interface Region Imaging Spectrograph Fe xxi 1354.08 Å forbidden line emission of two magnetic flux ropes (MFRs) that caused two fast coronal mass ejections with velocities of ≥1000 km s{sup −1} and strong flares (X1.6 and M6.5) on 2014 September 10 and 2015 June 22, respectively. The extreme-ultraviolet images at the 131 and 94 Å passbands provided by the Atmospheric Imaging Assembly on board Solar Dynamics Observatory reveal that both MFRs initially appear as suspended hot channel-like structures. Interestingly, part of the MFRs is also visible in the Fe xxi 1354.08 forbidden line, even prior to the eruption, e.g., for the SOL2014-09-10 event. However, the line emission is very weak and that only appears at a few locations but not the whole structure of the MFRs. This implies that the MFRs could be comprised of different threads with different temperatures and densities, based on the fact that the formation of the Fe xxi forbidden line requires a critical temperature (∼11.5 MK) and density. Moreover, the line shows a non-thermal broadening and a blueshift in the early phase. It suggests that magnetic reconnection at that time has initiated; it not only heats the MFR and, at the same time, produces a non-thermal broadening of the Fe xxi line but also produces the poloidal flux, leading to the ascension of the MFRs.

  4. High-resolution H-band spectroscopy of Be stars with SDSS-III/apogee. I. New Be stars, line identifications, and line profiles

    International Nuclear Information System (INIS)

    Chojnowski, S. Drew; Majewski, Steven R.; Hall, Matthew; Beaton, Rachael; Burton, Adam; Damke, Guillermo; Wilson, John; Whelan, David G.; Wisniewski, John P.; Shetrone, Matthew; Eikenberry, Steve; Hasselquist, Sten; Holtzman, Jon A.; Brewington, Howard; Brinkmann, J.; Mészáros, Szabolcs; Nidever, David; Schneider, Donald P.; Zasowski, Gail; Bizyaev, Dmitry

    2015-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has amassed the largest ever collection of multi-epoch, high-resolution (R∼22,500), H-band spectra for B-type emission line (Be) stars. These stars were targeted by APOGEE as telluric standard stars and subsequently identified via visual inspection as Be stars based on H i Brackett series emission or shell absorption in addition to otherwise smooth continua and occasionally non-hydrogen emission features. The 128/238 APOGEE Be stars for which emission had never previously been reported serve to increase the total number of known Be stars by ∼6%. Because the H band is relatively unexplored compared to other wavelength regimes, we focus here on identification of the H-band lines and analysis of the emission peak velocity separations (Δv p ) and emission peak intensity ratios (V/R) of the usually double-peaked H i and non-hydrogen emission lines. H i Br11 emission is found to preferentially form in the circumstellar disks at an average distance of ∼2.2 stellar radii. Increasing Δv p toward the weaker Br12–Br20 lines suggests these lines are formed interior to Br11. By contrast, the observed IR Fe ii emission lines present evidence of having significantly larger formation radii; distinctive phase lags between IR Fe ii and H i Brackett emission lines further supports that these species arise from different radii in Be disks. Several emission lines have been identified for the first time including C i 16895, a prominent feature in the spectra for almost a fifth of the sample and, as inferred from relatively large Δv p compared to the Br11–Br20, a tracer of the inner regions of Be disks. Emission lines at 15760 Å and 16781 Å remain unidentified, but usually appear along with and always have similar line profile morphology to Fe ii 16878. Unlike the typical metallic lines observed for Be stars in the optical, the H-band metallic lines, such as Fe ii 16878, never exhibit any evidence of

  5. An X- and Q-band Fe{sup 3+} EPR study of nanoparticles of magnetic semiconductor Zn{sub 1−x}Fe{sub x}O

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Sushil K., E-mail: skmisra@alcor.concordia.ca [Physics Department, Concordia University, Montreal, QC, Canada H3G 1M8 (Canada); Andronenko, S.I. [Physics Institute, Kazan Federal University, Kazan 420008 (Russian Federation); Thurber, A.; Punnoose, A. [Department of Physics, Boise State University, Boise, ID 83725-1570 (United States); Nalepa, A. [Max-Planck-Institut für Chemische Energie Konversion, Stifstrasse 34-36, 45470 Mülheim an der Ruhr (Germany)

    2014-08-01

    EPR studies on two types of nanoparticles of Fe{sup 3+} doped, 0.1–10%, ZnO, NL and QJ, prepared using similar chemical hydrolysis methods, in diethylene glycol, and in denatured ethanol solutions, respectively, were carried out at X-band (∼9.5 GHz) at 77 K and at Q-band (∼34.0 GHz) at 10, 80, and 295 K. To interpret the experimental results, EPR spectra were simulated by exact diagonalization of the spin-Hamiltonian matrix to identify the Fe ions at different magnetically active sites in these samples. The simulation for NL samples revealed that they contained (i) Fe{sup 3+} ions, which substituted for Zn ions, the zero-field splitting (ZFS) parameter which has a large distribution over the sample due to oxygen vacancies in the second coordination sphere; (ii) EPR signal from surface oxygen defects; and (iii) ferromagnetically (FM) coupled Fe ions with concentration of Fe more than 1%. The EPR spectra for QJ samples are very different from those for NL samples, exhibiting only rather intense FM EPR lines. The FM and EPR spectra in NL and/or QJ samples are found to vary strongly with differences in the surface morphology of nanoparticles. - Highlights: • X and Q band EPR studies on NL and QJ nanoparticles of Fe{sup 3+} doped ZnO at 10, 80, and 295 K. • Fe ions are present at different magnetically active sites in these samples. • NL samples consist of paramagnetic Fe{sup 3+} ions, and ferromagnetically coupled Fe ions. • QJ samples exhibit only intense ferromagnetic lines, different from QJ. • Spectra vary strongly with the surface morphology of nanoparticles.

  6. Quantum Monte Carlo detection of SU(2 symmetry breaking in the participation entropies of line subsystems

    Directory of Open Access Journals (Sweden)

    David J. Luitz, Nicolas Laflorencie

    2017-03-01

    Full Text Available Using quantum Monte Carlo simulations, we compute the participation (Shannon-R\\'enyi entropies for groundstate wave functions of Heisenberg antiferromagnets for one-dimensional (line subsystems of length $L$ embedded in two-dimensional ($L\\times L$ square lattices. We also study the line entropy at finite temperature, i.e. of the diagonal elements of the density matrix, for three-dimensional ($L\\times L\\times L$ cubic lattices. The breaking of SU(2 symmetry is clearly captured by a universal logarithmic scaling term $l_q\\ln L$ in the R\\'enyi entropies, in good agreement with the recent field-theory results of Misguish, Pasquier and Oshikawa [arXiv:1607.02465]. We also study the dependence of the log prefactor $l_q$ on the R\\'enyi index $q$ for which a transition is detected at $q_c\\simeq 1$.

  7. Angioplastia coronaria en la República Argentina. Comparación de los resultados en la fase hospitalaria de los estudios CONAREC V y CONAREC XIV

    Directory of Open Access Journals (Sweden)

    Sergio Baratta

    2007-01-01

    Full Text Available La angioplastia coronaria (ATC es una técnica para el tratamiento de la enfermedad coronaria que se encuentra en constante evolución. El registro CONAREC V relevó características de pacientes sometidos a angioplastia durante el año 1996. Diez años después publicamos los resultados del estudio CONAREC XIV. ObjetivoComparar las características demográficas y clínicas, la utilización de dispositivos y de pruebas funcionales, los resultados y las complicaciones de la ATC en el estudio CONAREC V con el estudio CONAREC XIV. Material y métodosSe unificaron las bases de datos de ambos protocolos. Se compararon las variables continuas por medio de la prueba de la t y las categóricas con la prueba de chi cuadrado. Se construyó un modelo de regresión logística para determinar si disminuyó la tasa de complicaciones en el año 2005, ajustando por confundidores.ResultadosLos pacientes del CONAREC XIV fueron más añosos (62,8 ± 10,8 versus 60,6 ± 10,9 años, con mayor prevalencia de hipertensión arterial (72,4% versus 61,3%; p < 0,001 y diabetes (19,2% versus 16,9%; p = 0,017 y menor de tabaquismo (22% versus 38%; p < 0,001; presentaron enfermedad de tres vasos (20,2% versus 14,8%; p < 0,001 y ATC de más de un vaso con mayor frecuencia (25,3% versus 11,8%; p < 0,001; se incrementaron el uso de stents (94,5% versus 48%; p < 0,001 y la indicación por cuadros estables (36,3% versus 18,2%; p < 0,001. El uso de pruebas funcionales en este contexto fue menor en el año 2005 (54% versus 65%; p < 0,001.En pacientes con infarto agudo de miocardio, en el CONAREC XIV se observó una prevalencia menor de infarto anterior (46% versus 57,8%; p < 0,005 y de shock cardiogénico (7,3% versus 13,5%; p = 0,017. La tasa de complicaciones mayores fue menor en el último protocolo, CONAREC XIV (3,1% versus 8,9%; p < 0,001. En el modelo multivariado, pertenecer al último estudio disminuyó el riesgo de padecer eventos (OR 0,41, IC 95% 0,26-0,64; p < 0

  8. Oxide ion diffusion mechanism related to Co and Fe ions in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ using in-situ X-ray absorption spectroscopy

    Science.gov (United States)

    Itoh, Takanori; Imai, Hideto

    2018-03-01

    The time changes of the white line and pre-edge intensities of Co and Fe K-edge in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3-δ (BSCF) were observed to estimate the oxide ion diffusion related to Co and Fe ions by using in - situ X-ray absorption spectroscopy (XAS) during oxidation. The 20 μm self-standing BSCF film was prepared for in - situ XAS measurements. The time changes of absorption were fitted to the exponential decay function with two terms. The longer relaxation time (τ), related to the oxide ion diffusion during the oxidation of BSCF, is dependent on temperature. The oxide ion diffusion coefficients (D) were calculated from the τ s estimated by in - situ XAS. The values of the activation energy (Ea) for D related to Co K-edge white line, Co pre-edge, and Fe pre-edge were 1.8-2.0 eV. The value of Ea for D related to Fe K-edge white line, however, was higher than other absorption values at approximately 2.3 eV. We discussed the oxide ion diffusion mechanism related to Co and Fe ions in BSCF using in - situ XAS.

  9. NLTE masking and the Kiev Fe I oscillator strengths

    International Nuclear Information System (INIS)

    Rutten, R.J.

    1983-01-01

    This contribution serves to advertise the empirical solar-spectrum determinations of the oscillator strengths of 860 Fe I lines by Gurtovenko and Kostik (1981), by showing that these Kiev data contain just the lines needed in cool-star abundance analyses, and by explaining why they are so good. (Auth.)

  10. Secondary particles precipitates in Be-Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Filippov, V. P., E-mail: vpfilippov@mephi.ru; Petrov, V. I.; Martynenko, S. S.; Salomasov, V. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

    2016-12-15

    Mössbauer spectra of monocrystalline Be-Fe alloy (0.85 % Fe) were obtained with the use of resonant detector after isothermal annealing at 600 °C for total duration of 2659 hours, and Mössbauer spectra of coarse-grained Be-Fe alloys (0,09-0,80 % Fe) samples were obtained after annealing at 500-600 °C for different durations. The alloys were prepared from the beryllium of different purity. Spectra of phases were fitted by a convolution equation of the three Lorentz lines. The coherent analysis of the solid solution decomposition process by means of the kinetic law classification and the secondary particles precipitate growth processes based on the diffusion models has been implemented. Nucleation on the numerous dislocation clusters and diffusion growth of the FeBe {sub 11} nano-particles are the dominant processes in the analyzed materials. The phase distribution, the incubation period and the diffusion path were obtained. The dependence between the impurity concentration and Mössbauer parameters of the phases is discussed.

  11. Secondary particles precipitates in Be-Fe alloys

    International Nuclear Information System (INIS)

    Filippov, V. P.; Petrov, V. I.; Martynenko, S. S.; Salomasov, V. A.

    2016-01-01

    Mössbauer spectra of monocrystalline Be-Fe alloy (0.85 % Fe) were obtained with the use of resonant detector after isothermal annealing at 600 °C for total duration of 2659 hours, and Mössbauer spectra of coarse-grained Be-Fe alloys (0,09-0,80 % Fe) samples were obtained after annealing at 500-600 °C for different durations. The alloys were prepared from the beryllium of different purity. Spectra of phases were fitted by a convolution equation of the three Lorentz lines. The coherent analysis of the solid solution decomposition process by means of the kinetic law classification and the secondary particles precipitate growth processes based on the diffusion models has been implemented. Nucleation on the numerous dislocation clusters and diffusion growth of the FeBe _1_1 nano-particles are the dominant processes in the analyzed materials. The phase distribution, the incubation period and the diffusion path were obtained. The dependence between the impurity concentration and Mössbauer parameters of the phases is discussed.

  12. ELLERMAN BOMBS AT HIGH RESOLUTION. II. TRIGGERING, VISIBILITY, AND EFFECT ON UPPER ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Vissers, Gregal J. M.; Rouppe van der Voort, Luc H. M.; Rutten, Robert J., E-mail: g.j.m.vissers@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)

    2013-09-01

    We use high-resolution imaging spectroscopy with the Swedish 1-m Solar Telescope (SST) to study the transient brightenings of the wings of the Balmer H{alpha} line in emerging active regions that are called Ellerman bombs. Simultaneous sampling of Ca II 8542 A with the SST confirms that most Ellerman bombs also occur in the wings of this line, but with markedly different morphology. Simultaneous images from the Solar Dynamics Observatory (SDO) show that Ellerman bombs are also detectable in the photospheric 1700 A continuum, again with differing morphology. They are also observable in 1600 A SDO images, but with much contamination from C IV emission in transition-region features. Simultaneous SST spectropolarimetry in Fe I 6301 A shows that Ellerman bombs occur at sites of strong-field magnetic flux cancellation between small bipolar strong-field patches that rapidly move together over the solar surface. Simultaneous SDO images in He II 304 A, Fe IX 171 A, and Fe XIV 211 A show no clear effect of the Ellerman bombs on the overlying transition region and corona. These results strengthen our earlier suggestion, based on H{alpha} morphology alone, that the Ellerman bomb phenomenon is a purely photospheric reconnection phenomenon.

  13. Modeling 13.3nm Fe XXIII Flare Emissions Using the GOES-R EXIS Instrument

    Science.gov (United States)

    Rook, H.; Thiemann, E.

    2017-12-01

    The solar EUV spectrum is dominated by atomic transitions in ionized atoms in the solar atmosphere. As solar flares evolve, plasma temperatures and densities change, influencing abundances of various ions, changing intensities of different EUV wavelengths observed from the sun. Quantifying solar flare spectral irradiance is important for constraining models of Earth's atmosphere, improving communications quality, and controlling satellite navigation. However, high time cadence measurements of flare irradiance across the entire EUV spectrum were not available prior to the launch of SDO. The EVE MEGS-A instrument aboard SDO collected 0.1nm EUV spectrum data from 2010 until 2014, when the instrument failed. No current or future instrument is capable of similar high resolution and time cadence EUV observation. This necessitates a full EUV spectrum model to study EUV phenomena at Earth. It has been recently demonstrated that one hot flare EUV line, such as the 13.3nm Fe XXIII line, can be used to model cooler flare EUV line emissions, filling the role of MEGS-A. Since unblended measurements of Fe XXIII are typically unavailable, a proxy for the Fe XXIII line must be found. In this study, we construct two models of this line, first using the GOES 0.1-0.8nm soft x-ray (SXR) channel as the Fe XXIII proxy, and second using a physics-based model dependent on GOES emission measure and temperature data. We determine that the more sophisticated physics-based model shows better agreement with Fe XXIII measurements, although the simple proxy model also performs well. We also conclude that the high correlation between Fe XXIII emissions and the GOES 0.1-0.8nm band is because both emissions tend to peak near the GOES emission measure peak despite large differences in their contribution functions.

  14. Observational study of ion-electron equilibration and of cloud evaporation in supernova remnants under the HEAO-2 guest investigator program. Final project report, 1 June 1985-30 September 1986

    International Nuclear Information System (INIS)

    Teske, R.G.

    1986-09-01

    Observations of three selected supernovae remnants (Cygnus Loop, IC 443, and Puppis A) were made in the forbidden coronal iron lines (Fe X) lambda 6374 and (Fe XIV) lambda 5303. The resulting data was compared quantitatively with Einstein images of the same objects, and an attempt was made to determine (a) the process by which ion and electron energies are equilibrated behind the shock front in the ISM and (b) whether cloud evaporation occurs within the hot remnant interiors. Spatially-resolved x-ray emission were modeled for Sedov-Taylor blast wave models of supernovae remnants (SNR) under conditions of non-equlibrium ionization. The computations are intended to provide results that can be directly compared with Einstein high resolution image (HRI) and imaging proportional counter (IPS) data. The computer program for predicting the spatial distribution of HRI and IPS counting rates was completed, and final testing of it had begun

  15. DETECTION OF REST-FRAME OPTICAL LINES FROM X-SHOOTER SPECTROSCOPY OF WEAK EMISSION-LINE QUASARS

    International Nuclear Information System (INIS)

    Plotkin, Richard M.; Gallo, Elena; Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, W. N.; Luo, Bin; Schneider, Donald P.; Fan, Xiaohui; Lira, Paulina; Richards, Gordon T.; Strauss, Michael A.; Wu, Jianfeng

    2015-01-01

    Over the past 15 yr, examples of exotic radio-quiet quasars with intrinsically weak or absent broad emission line regions (BELRs) have emerged from large-scale spectroscopic sky surveys. Here, we present spectroscopy of seven such weak emission line quasars (WLQs) at moderate redshifts (z = 1.4–1.7) using the X-shooter spectrograph, which provides simultaneous optical and near-infrared spectroscopy covering the rest-frame ultraviolet (UV) through optical. These new observations effectively double the number of WLQs with spectroscopy in the optical rest-frame, and they allow us to compare the strengths of (weak) high-ionization emission lines (e.g., C iv) to low-ionization lines (e.g., Mg ii, Hβ, Hα) in individual objects. We detect broad Hβ and Hα emission in all objects, and these lines are generally toward the weaker end of the distribution expected for typical quasars (e.g., Hβ has rest-frame equivalent widths ranging from 15–40 Å). However, these low-ionization lines are not exceptionally weak, as is the case for high-ionization lines in WLQs. The X-shooter spectra also display relatively strong optical Fe ii emission, Hβ FWHM ≲ 4000 km s −1 , and significant C iv blueshifts (≈1000–5500 km s −1 ) relative to the systemic redshift; two spectra also show elevated UV Fe ii emission, and an outflowing component to their (weak) Mg ii emission lines. These properties suggest that WLQs are exotic versions of “wind-dominated” quasars. Their BELRs either have unusual high-ionization components, or their BELRs are in an atypical photoionization state because of an unusually soft continuum

  16. X-ray spectral line coincidences between fluorine VIII (and IX) and transition metal lines

    International Nuclear Information System (INIS)

    Charatis, G.; Rockett, P.D.; Burkhalter, P.G.

    1983-01-01

    X-ray spectroscopy was performed in the 12 to 15 A region, recording L-shell lines from selected laser-irradiated transition metals. Line coincidences and near coincidences were identified between Fe, Cr, Mn, and Ni L-spectra, and F VIII and F IX K-shell lines. Wavelengths were determined to accuracies of 1 to 3 mA and will be utilized in selecting potential pumping candidates in future x-ray lasing schemes. High-resolution x-ray spectra were collected under controlled illumination and target conditions using 1.05 μm and 0.527 μm laser excitation with the KMS CHROMA laser

  17. Microbeam X-ray fluorescence mapping of Cu and Fe in human prostatic carcinoma cell lines using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, K.M.J.; Leitao, R.G.; Oliveira-Barros, E.G.; Oliveira, M.A.; Canellas, C.G.L.; Anjos, M.J.; Nasciutti, L.E.; Lopes, R.T., E-mail: kjose@nuclear.ufrj.br, E-mail: marcelin@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br, E-mail: roberta@lin.ufrj.br, E-mail: eligouveab@gmail.com, E-mail: maria_aparecida_ufrj@yahoo.com.br, E-mail: luiz.nasciutti@histo.ufrj.br, E-mail: roberta.leitao@uerj.br, E-mail: marcelin@uerj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Laboratorio de Instrumentacao Nuclear; Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Ciencias Biomedicas; Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Instituto de Fisica

    2017-11-01

    Cancer is a worldwide public health problem and prostate cancer continues to be one of the most common fatal cancers in men. Copper plays an important role in the aetiology and growth of tumours however, whether intratumoral copper is actually elevated in prostate cancer patients has not been established. Iron, an important trace element, plays a vital function in oxygen metabolism, oxygen uptake, and electron transport in mitochondria, energy metabolism, muscle function, and hematopoiesis. The X-ray microfluorescence technique (μXRF) is a rapid and non-destructive method of elemental analysis that provides useful elemental information about samples without causing damage or requiring extra sample preparations. This study investigated the behavior of cells in spheroids of human prostate cells, tumour cell line (DU145) and normal cell line (RWPE-1), after supplementation with zinc chloride by 24 hours using synchrotron X-ray microfluorescence (μSRXRF). The measurements were performed with a standard geometry of 45 deg of incidence, excited by a white beam using a pixel of 25 μm and a time of 300 ms/pixel at the XRF beamline at the Synchrotron Light National Laboratory (Campinas, Brazil). The results by SRμXRF showed non-uniform Cu and Fe distributions in all the spheroids analyzed. (author)

  18. Microbeam X-ray fluorescence mapping of Cu and Fe in human prostatic carcinoma cell lines using synchrotron radiation

    International Nuclear Information System (INIS)

    Rocha, K.M.J.; Leitao, R.G.; Oliveira-Barros, E.G.; Oliveira, M.A.; Canellas, C.G.L.; Anjos, M.J.; Nasciutti, L.E.; Lopes, R.T.; Universidade Federal do Rio de Janeiro; Universidade do Estado do Rio de Janeiro

    2017-01-01

    Cancer is a worldwide public health problem and prostate cancer continues to be one of the most common fatal cancers in men. Copper plays an important role in the aetiology and growth of tumours however, whether intratumoral copper is actually elevated in prostate cancer patients has not been established. Iron, an important trace element, plays a vital function in oxygen metabolism, oxygen uptake, and electron transport in mitochondria, energy metabolism, muscle function, and hematopoiesis. The X-ray microfluorescence technique (μXRF) is a rapid and non-destructive method of elemental analysis that provides useful elemental information about samples without causing damage or requiring extra sample preparations. This study investigated the behavior of cells in spheroids of human prostate cells, tumour cell line (DU145) and normal cell line (RWPE-1), after supplementation with zinc chloride by 24 hours using synchrotron X-ray microfluorescence (μSRXRF). The measurements were performed with a standard geometry of 45 deg of incidence, excited by a white beam using a pixel of 25 μm and a time of 300 ms/pixel at the XRF beamline at the Synchrotron Light National Laboratory (Campinas, Brazil). The results by SRμXRF showed non-uniform Cu and Fe distributions in all the spheroids analyzed. (author)

  19. Magnetic, electrical transport and electron spin resonance studies of Fe-doped manganite LaMn0.7Fe0.3O3+δ

    International Nuclear Information System (INIS)

    Liu, X.J.; Li, Z.Q.; Yu, A.; Liu, M.L.; Li, W.R.; Li, B.L.; Wu, P.; Bai, H.L.; Jiang, E.Y.

    2007-01-01

    We have investigated the magnetic, electrical transport and electron spin resonance (ESR) properties of polycrystalline Fe-doped manganite LaMn 0.7 Fe 0.3 O 3+ δ prepared by sol-gel method. A typical cluster-glass feature is presented by DC magnetization and AC susceptibility measurements and a sharp but shallow memory effect was observed. Symmetrical Lorentzian lines of the Mn/Fe spectra were detected above 120 K, where the sample is a paramagnetic (PM) insulator. When the temperature decreases from 120 K, magnetic clusters contributed from ferromagnetic (FM) interaction between Mn 3+ and Mn 3+ /Fe 3+ ions develop and coexist with PM phase. At lower temperature, these FM clusters compete with antiferromagnetic (AFM) ones between Fe 3+ ions, which are associated with a distinct field-cooled (FC) effect in characteristic of cluster-glass state

  20. THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

    International Nuclear Information System (INIS)

    Marinello, M.; Rodríguez-Ardila, A.; Garcia-Rissmann, A.; Sigut, T. A. A.; Pradhan, A. K.

    2016-01-01

    We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission

  1. THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

    Energy Technology Data Exchange (ETDEWEB)

    Marinello, M. [Universidade Federal de Itajubá, Rua Doutor Pereira Cabral 1303, 37500-903, Itajubá, MG (Brazil); Rodríguez-Ardila, A.; Garcia-Rissmann, A. [Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, Itajubá, MG, 37504-364 (Brazil); Sigut, T. A. A. [The University of Western Ontario, London, ON N6A 3K7 (Canada); Pradhan, A. K., E-mail: murilo.marinello@gmail.com [McPherson Laboratory, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210-1173 (United States)

    2016-04-01

    We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission.

  2. X-ray imaging spectroscopic diagnostics on Nike

    Science.gov (United States)

    Aglitskiy, Y.; Karasik, M.; Serlin, V.; Weaver, J. L.; Oh, J.; Obenschain, S. P.; Ralchenko, Yu.

    2017-10-01

    Electron temperature and density diagnostics of the laser plasma produced within the focal spot of the NRL's Nike laser are being explored with the help of X-ray imaging spectroscopy. Spectra of He-like and H-like ions were taken by Nike focusing spectrometers in a range of lower (1.8 kev, Si XIV) and higher (6.7 kev, Fe XXV) x-ray energies. Data that were obtained with spatial resolution were translated into the temperature and density as functions of distance from the target. As an example electron density was determined from He-like satellites to Ly-alpha in Si XIV. The dielectronic satellites with intensity ratios that are sensitive to collisional transfer of population between different triplet groups of double-excited states 2l2l' in Si XIII were observed with high spatial and spectral resolution Lineouts taken at different axial distances from the planar Si target show changing spectral shapes due to the different electron densities as determined by supporting non-LTE simulations. These shapes are relatively insensitive to the plasma temperature which was measured using different spectral lines. This work was supported by the US DOE/NNSA.

  3. La Maison du Roi sous Louis XIV, une troupe d’élite. Étude tactique

    OpenAIRE

    Chauviré, Frédéric

    2009-01-01

    La Maison du roi constitue le corps le plus prestigieux de l’armée royale. Mais c’est aussi une troupe d’élite, redoutée sur tous les champs de bataille. Sa supériorité tactique trouve son origine dans la singularité de sa doctrine de combat. Beaucoup plus manœuvrière que les régiments ordinaires, elle s’en distingue également par sa conduite de la charge : choix de l’arme blanche, adoption d’une allure élevée et recherche du choc. Les qualités de cette troupe expliquent que Louis XIV ait vou...

  4. Umbelliprenin-coated Fe3O4 magnetite nanoparticles: Antiproliferation evaluation on human Fibrosarcoma cell line (HT-1080)

    International Nuclear Information System (INIS)

    Khorramizadeh, M.R.; Esmail-Nazari, Z.; Zarei-Ghaane, Z.; Shakibaie, M.; Mollazadeh-Moghaddam, K.; Iranshahi, M.; Shahverdi, A.R.

    2010-01-01

    The potential applications of Fe 3 O 4 magnetite nanoparticles (MNPs) in nanomedicine as drug delivery systems are well known. In this study we prepared umbelliprenin-coated Fe 3 O 4 MNPs and evaluated the antiproliferative effect of combination in vitro. After synthesis of Fe 3 O 4 MNPs, particles were characterized by transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction spectroscopy techniques. The natural candidate compound - umbelliprenin- was isolated and identified and umbelliprenin-coated Fe 3 O 4 MNPs were prepared, using precipitation method. The surface chemistry of umbelliprenin-coated Fe 3 O 4 MNPs as well as their thermal decomposition characteristics was examined using Fourier transform infrared spectroscopy and Thermogravimetric Analyzer equipment, respectively. HT-1080 cells were cultured until the logarithmic phase of growth, and MTT assay was successfully carried out to evaluate the possible cytotoxic effects of umbelliprenin-coated Fe 3 O 4 MNPs in viable cells in vitro. The results demonstrated that umbelliprenin has moderate antiproliferative effects with IC 50 value of 50 μg/mL. However, the combination of umbelliprenin and Fe 3 O 4 MNPs showed the IC 50 value of 9 μg/mL. In other words, cell proliferation decreased to the remarkably-low proportion of 45% after treating cells with umbelliprenin-coated Fe 3 O 4 MNPs. This suggests that with the aid of nanoparticles as carriers, natural products may have even broader range of medical applications in future.

  5. Neon-like Iron Ion Lines Measured in NIFS/Large Helical Device (LHD) and Hinode/EUV Imaging Spectrometer (EIS)

    Science.gov (United States)

    Watanabe, Tetsuya; Hara, Hirohisa; Murakami, Izumi; Kato, Daiji; Sakaue, Hiroyuki A.; Morita, Shigeru; Suzuki, Chihiro; Tamura, Naoki; Yamamoto, Norimasa; Nakamura, Nobuyuki

    2017-06-01

    Line intensities emerging from the Ne-sequence iron ion (Fe XVII) are measured in the laboratory, by the Large Helical Device at the National Institute for Fusion Science, and in the solar corona by the EUV Imaging Spectrometer (EIS) on board the Hinode mission. The intensity ratios of Fe XVII λ 204.6/λ 254.8 are derived in the laboratory by unblending the contributions of the Fe XIII and XII line intensities. They are consistent with theoretical predictions and solar observations, the latter of which endorses the in-flight radiometric calibrations of the EIS instrument. The still remaining temperature-dependent behavior of the line ratio suggests the contamination of lower-temperature iron lines that are blended with the λ 204.6 line.

  6. Neon-like Iron Ion Lines Measured in NIFS/Large Helical Device (LHD) and Hinode /EUV Imaging Spectrometer (EIS)

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tetsuya; Hara, Hirohisa [National Astronomical Observatory, National Institutes of Natural Sciences 2-21-1 Osawa Mitaka Tokyo, 181-8588 (Japan); Murakami, Izumi; Kato, Daiji; Morita, Shigeru [SOKENDAI (Graduate University for Advanced Studies) Hayama, Miura-gun, Kanagawa, 240-0193 (Japan); Sakaue, Hiroyuki A.; Suzuki, Chihiro; Tamura, Naoki [National Institute for Fusion Science, National Institutes of Natural Sciences 322-6 Oroshi-cho, Toki Gifu, 509-5292 (Japan); Yamamoto, Norimasa [Chubu University 1200 Matsumoto-cho, Kasugai Aichi, 487-0027 (Japan); Nakamura, Nobuyuki, E-mail: watanabe@uvlab.mtk.nao.ac.jp [The University of Electro-Communications 1-5-1 Chofugaoka, Chofu Tokyo, 182-8585 (Japan)

    2017-06-10

    Line intensities emerging from the Ne-sequence iron ion (Fe xvii) are measured in the laboratory, by the Large Helical Device at the National Institute for Fusion Science, and in the solar corona by the EUV Imaging Spectrometer (EIS) on board the Hinode mission. The intensity ratios of Fe xvii λ 204.6/ λ 254.8 are derived in the laboratory by unblending the contributions of the Fe xiii and xii line intensities. They are consistent with theoretical predictions and solar observations, the latter of which endorses the in-flight radiometric calibrations of the EIS instrument. The still remaining temperature-dependent behavior of the line ratio suggests the contamination of lower-temperature iron lines that are blended with the λ 204.6 line.

  7. OLDTURKISHMEDICINE(XIV. - XVI. CENTURIESPROCEDURES FORMEASURINGAND DIMENSIONS ESKİ TÜRK TIBBINDA (XIV. - XVI. YÜZYILLAR ÖLÇÜLER VE ÖLÇME USULLERİ

    Directory of Open Access Journals (Sweden)

    Gürkan GÜMÜŞATAM

    2012-01-01

    Full Text Available Turkishhistory of science, and with it the language ofsciencehas advancedthe course ofTurkishXIV.-XV.centurymedicalbooksterms of the datacontainsrichdata. Theimportanceof scientificworkswrittenin thiscenturyTurkishphysiciansin the works ofthe eraby puttingadministratorsin favor ofTurkish,complied withrequests. In this way,Turkishas the language ofsciencehas grown. Since theTurkishworks ofwritingfromamong those wholivedcenturiesphysicianshaveindicated. Centuries,written inplain languageratherthanthe worksnextpostin the works ofthe erathatthe presence ofdifferenttypes offace, observethe waysof their usage. The presence oftherelevanttermsofthesedimensionsandscalesare also available. The names given tounitsof measure, scales, and their useof suchwords inthe relevant departmentsin terms ofreachingasource ofpharmaceuticalproductions. The majority ofdetectionand usesthese termsfromArabicand Persianformedthe subject ofthisreview. The datasetwasselectedsixmedicalbook. As a result,Turkish,Arabicand Persianas well asinclusionof measurementunitsby using thedrawingsinthe waysof expressionis the resulthad been reached. Türk bilim tarihi ve onunla birlikte gelişme göstermiş Türk bilim dilinin seyri XIV.-XVI. yüzyıl tıp kitaplarındaki veriler bakımından zengin bulgular içerir. İlmî eserlerin Türkçe yazılmasına önem gösterilen bu dönemde hekimler Türkçeden yana tavır koyarak devrin yöneticilerinin isteklerine uymuşlardır. Bu sayede Türkçe bilim dili olarak gelişme göstermiştir. Eserlerini Türkçe yazmaktan yana olanlar arasında belirtilen yüzyıllar arasında yaşamış hekimler de vardır. Sonraki yüzyılllarda yazılmış eserlere nazaran oldukça yalın bir dille kaleme alınmış devrin eserlerinde değişik türden söz varlığıyla karşılaşmakta, bunların kullanım yollarını gözlenebilmektedir. Bu söz varlığı arasında ölçüler ve ölçeklerle ilgili terimler de bulunur. Ölçü birimlerine verilen adlar,

  8. Properties of Narrow line Seyfert 1 galaxies

    Science.gov (United States)

    Rakshit, Suvendu; Stalin, Chelliah Subramonian; Chand, Hum; Zhang, Xue-Guang

    2018-04-01

    Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line 10 pixel-1. A strong correlation between the Hα and Hα emission lines is found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of Hα, Hα and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the R4570 - λEdd diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R>10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 ± 0.9) than BLSy1 galaxies (2.4 ± 0.8). It is anti-correlated with the Hα width but correlated with the FeII strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.

  9. On the X-ray lines in the afterglows of GRBs

    CERN Document Server

    Dar, Arnon; De Rújula, Alvaro; Dar, Arnon; Dado, Shlomo

    2003-01-01

    The observation of X-ray lines in the afterglow of GRB 011211 has been reported, and challenged. The lines were interpreted as blue-shifted X-rays characteristic of a set of photoionized ``metals'', located in a section of a supernova shell illuminated by a GRB emitted a couple of days after the supernova explosion. We show that the most prominent reported lines coincide with the ones predicted in the ``cannonball'' model of GRBs. In this model, the putative signatures are Hydrogen lines, boosted by the (highly relativistic) motion of the cannonballs (CBs). The corresponding Doppler boost can be extracted from the fit to the observed I-, R- and V-band light-curves of the optical afterglow of GRB 011211, so that, since the redshift is also known, the line energies are --in the CB model-- absolute predictions. We also discuss other GRBs of known redshift which show spectral features generally interpreted as Fe lines, or Fe recombination edges. The ensemble of results is very encouraging from the CB-model's poin...

  10. The local structure and magnetic interactions between Fe3+ and V4+ ions in lithium–phosphate glasses

    International Nuclear Information System (INIS)

    Andronache, Constantin I.

    2012-01-01

    Electron Paramagnetic Resonance (EPR) provides a useful tool not only as a probe of local structure and short range order in glasses, but also of magnetic interactions in the glasses containing suitable magnetic ions. We have analyzed the spectra of xFe 2 O 3 ·(100 − x)[P 2 O 5 ·Li 2 O] and x(Fe 2 O 3 ·V 2 O 5 )·(100 − x)[P 2 O 5 ·Li 2 O] glass systems, with 0 2 O 5 ·Li 2 O] stands for 50Li 2 O·50P 2 O 5 glass composition. For samples x > 50 mol % a study indicates the presence of crystalline α Fe 2 O 3 in the glasses. Observed spectra have resonance lines centered at g ∼ 4.3 and g ∼ 2.0 typical for Fe 3+ and V 4+ ions present in the oxide glasses. For low contend of transition metal (TM) oxides (Fe 2 O 3 or V 2 O 5 ·Fe 2 O 3 ) the spectra present a hyperfine structure typical for isolated V 4+ ions. With the increasing of TM content, the EPR absorption signal showing hyperfine structure superposed by a broad line without hyperfine structure characteristic for clustered ions. At high TM content, the vanadium hyperfine structure disappears and only the broad line can be observed in the spectra. -- Highlights: ► Lithium phosphate glass with Fe and V ions were investigated by means of EPR. ► The composition dependence of line intensity were investigated. ► The spin Hamiltonian parameters for VO 2+ were evaluated.

  11. Why the paper CERN-PH-EP-2009-015 (arXiv:0903.4762) is scientifically unacceptable

    CERN Document Server

    Bolshakova, A; Chelkov, G; Dedovitch, D; Elagin, A; Gostkin, M; Guskov, A; Krumshtein, Z; Nefedov, Yu; Nikolaev, K; Zhemchugov, A; Dydak, F; Wotschack, J; De Min, A; Ammosov, V; Gapienko, V; Koreshev, V; Semak, A; Sviridov, Yu; Usenko, E; Zaets, V

    2009-01-01

    The paper CERN-PH-EP-2009-015 (arXiv:0903.4762) by A. Bagulya et al. violates standards of quality of work and scientific ethics on several counts. The paper contains assertions that contradict established detector physics. The paper falls short of proving the correctness of the authors' concepts and results. The paper ignores or quotes misleadingly pertinent published work. The paper ignores the fact that the authors' concepts and results have already been shown wrong in the published literature. The authors seem unaware that cross-section results from the 'HARP Collaboration' that are based on the paper's concepts and algorithms are in gross disagreement with the results of a second analysis of the same data, and with the results of other experiments.

  12. Thermodynamics of the Solar Corona and Evolution of the Solar Magnetic Field as Inferred from the Total Solar Eclipse Observations of 11 July 2010

    Science.gov (United States)

    Habbal, Shadia Rifai; Druckmueller, Miloslav; Morgan, Huw; Ding, Adalbert; Johnson, Judd; Druckmuellerova, Hana; Daw, Adrian; Arndt, Martina B.; Dietzel, Martin; Saken, Jon

    2011-01-01

    We report on multi-wavelength observations of the corona taken simultaneously in broadband white light, and in seven spectral lines, H-alpha 656.3 nm, Fe IX 435.9 nm, Fe X 637.4 nm, Fe XI 789.2 nm, Fe XIII 1074.7 nm, Fe XIV 530.3 nm and Ni XV 670.2 nm. The observations were made during the total solar eclipse of 11 July 2010 from the atoll of Tatakoto in French Polynesia. Simultaneous imaging with narrow bandpass filters in each of these spectral lines and in their corresponding underlying continua maximized the observing time during less than ideal observing conditions and yielded outstanding quality data. The application of two complementary image processing techniques revealed the finest details of coronal structures at 1" resolution in white light, and 6.5" in each of the spectral lines. This comprehensive wavelength coverage confirmed earlier eclipse findings that the solar corona has a clear two-temperature structure: The open field lines, expanding outwards from the solar surface, are characterized by electron temperatures near 1 X 10(exp 6) K, while the hottest plasma around 2X 10(exp 6) K resides in loop-like structures forming the bulges of streamers. The first images of the corona in the forbidden lines of Fe IX and Ni XV, showed that there was very little coronal plasma at temperatures below 5 X 10(exp 5) K and above 2.5X 10(exp 6) K. The data also enabled temperature differentiations as low as 0:2 X 10(exp 6) K in different density structures. These observations showed how the passage of CMEs through the corona, prior to totality, produced large scale ripples and very sharp streaks, which could be identified with distinct temperatures for the first time. The ripples were most prominent in emission from spectral lines associated with temperatures around 10(exp 6) K. The most prominent streak was associated with a conical-shaped void in the emission from the coolest line of Fe IX and from the hottest line of Ni XV. A prominence, which erupted prior to

  13. Identification of S VIII through S XIV emission lines between 17.5 and 50 nm in a magnetically confined plasma

    Science.gov (United States)

    McCarthy, K. J.; Tamura, N.; Combs, S. K.; García, R.; Hernández Sánchez, J.; Navarro, M.; Panadero, N.; Pastor, I.; Soleto, A.; the TJ-II Team

    2018-03-01

    43 spectral emission lines from F-like to Li-like sulphur ions have been identified in the wavelength range from 17.5 to 50 nm in spectra obtained following tracer injection into plasmas created in a magnetically confined plasma device, the stellarator TJ-II. Plasmas created and maintained in this heliac device with electron cyclotron resonance heating achieve central electron temperatures and densities up to 1.5 keV and 8 × 1018 m-3, respectively. Tracer injections were performed with ≤6 × 1016 atoms of sulphur contained within ˜300 μm diameter polystyrene capsules, termed tracer encapsulated solid pellets, using a gas propulsion system to achieve velocities between 250 and 450 m s-1. Once ablation of the exterior polystyrene shell by plasma particles is completed, the sulphur is deposited in the plasma core where it is ionized up to S+13 and transported about the plasma. In order to aid line identification, which is made using a number of atomic line emission databases, spectra are collected before and after injection using a 1 m focal length normal incidence spectrometer equipped with a CCD camera. This work is motivated by the need to clearly identify sulphur emission lines in the vacuum ultraviolet range of magnetically confined plasmas, as sulphur x-ray emission lines are regularly observed in both tokamak and stellarator plasmas.

  14. Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) with Standard Reference Line for the Analysis of Stainless Steel.

    Science.gov (United States)

    Fu, Hongbo; Dong, Fengzhong; Wang, Huadong; Jia, Junwei; Ni, Zhibo

    2017-08-01

    In this work, calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is used to analyze a certified stainless steel sample. Due to self-absorption of the spectral lines from the major element Fe and the sparse lines of trace elements, it is usually not easy to construct the Boltzmann plots of all species. A standard reference line method is proposed here to solve this difficulty under the assumption of local thermodynamic equilibrium so that the same temperature value for all elements present into the plasma can be considered. Based on the concentration and rich spectral lines of Fe, the Stark broadening of Fe(I) 381.584 nm and Saha-Boltzmann plots of this element are used to calculate the electron density and the plasma temperature, respectively. In order to determine the plasma temperature accurately, which is seriously affected by self-absorption, a pre-selection procedure for eliminating those spectral lines with strong self-absorption is employed. Then, one spectral line of each element is selected to calculate its corresponding concentration. The results from the standard reference lines with and without self-absorption of Fe are compared. This method allows us to measure trace element content and effectively avoid the adverse effects due to self-absorption.

  15. A CEMS study of surface oxidation of Fe-Ni alloys

    International Nuclear Information System (INIS)

    Cruz, B.; Tabares, J.A.; Bohorquez, A.; Perez Alcazar, G.A.

    1997-01-01

    A study by conversion electron Moessbauer spectroscopy (CEMS) carried out by using a parallel plate avalanche counter with samples of Fe-Ni alloys (50 and 65 at.% Fe) is reported. Each sample was analyzed without oxidation and after heating it under an oxygen atmosphere at 200 C. All CEMS measurements were carried out at room temperature. In both samples (50 and 65 at.% Fe), without oxidation and after oxidation, the Moessbauer spectra showed a six line magnetic spectrum according to their ferromagnetic character, with a broad hyperfine field distribution (HFD), according to the disordered character of the alloys. The obtained mean hyperfine field (MHF) for the sample 50 at.% Fe was 30.9 T, meanwhile for the invar composition (65 at.% Fe) was 25.5 T, which is close to values previously reported by transmission Moessbauer spectroscopy (TMS). Results from the treated samples (with oxidation at 200 C) showed a difference in the surface composition as a result of this process. In the 50 at.% Fe sample, additionally appeared a double that could be assigned to an oxihydroxide of Fe 3+ . Otherwise, the 65 at.% Fe sample (invar) presented ferromagnetic oxides (α-Fe 2 O 3 and Fe 3 O 4 ) with a large relative area (82.5%). (orig.)

  16. The Vega of Granada in the late Middle Ages (XIV-XVI Centuries: almunias versus alquerías

    Directory of Open Access Journals (Sweden)

    Carmen Trillo San José

    2017-10-01

    Full Text Available Peri-urban areas of cities in Al-Andalus was a very diverse rural habitat. Aristocratic property was present in these environments and has received little attention. Indeed, we know very little about the elites of Al-Andalus in comparison to those of other western medieval countries. In this study we have examined the hinterland of the city of Granada during the Naṣrid era (XIV-XV centuries, paying special attention to two features of the distribution of its population: alquerías (villages, settlements of the rural community par excellence, and almunias or aristocatic estates.

  17. Cr(VI) retention and transport through Fe(III)-coated natural zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2012-06-30

    Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

  18. Operational method of a ferroelectric (Fe)-NAND flash memory array

    International Nuclear Information System (INIS)

    Wang, Shouyu; Takahashi, Mitue; Li, Qiu-Hong; Sakai, Shigeki; Takeuchi, Ken

    2009-01-01

    Operations of arrayed ferroelectric (Fe)-NAND flash memory cells: erase, program and read were demonstrated for the first time using a small cell array of four word lines by two NAND strings. The memory cells and select-gate transistors were all n-channel Pt/SrBi 2 Ta 2 O 9 /Hf-Al-O/Si ferroelectric-gate field effect transistors. The erase was performed by applying 10 µs wide 7 V pulses to n- and p-wells. The program was performed by applying 10 µs wide 7 V pulses to selected word lines. Accumulated read currents of 51 programmed patterns in the Fe-NAND flash memory cell array successfully showed distribution of the two distinguishable '0' and '1' states. The margin between the two states became wider by applying a verification technique in programming a cell out of the eight. Retention times of bit-line currents were obtained over 33 h for both the '0' and '1' states in a program pattern

  19. FeII/MgII Emission Line Ratio in High Redshift Quasars

    DEFF Research Database (Denmark)

    Dietrich, M.; Hamann, F.; Appenzeller, I.

    2003-01-01

    the evolution of the FeII/MgII ratio over a wider range in cosmic time, we measured this ratio for composite quasar spectra which cover a redshift range of 0 4 quasars must have started already at an epoch corresponding to z_f = 6 to 9, when the age of the universe was ~0.5 Gyr (H_o = 72 km/s/Mpc, Omega_M = 0...

  20. An experimental observation of the different behavior of ionic and neutral lines of iron as a function of number density in a binary carbon–iron mixture

    International Nuclear Information System (INIS)

    Sivakumar, P.; Taleh, L.; Markushin, Y.; Melikechi, N.; Lasue, J.

    2013-01-01

    We report on the dependence of the intensities of atomic and ionic lines emitted by a nanosecond laser-induced plasma on the atomic number densities of the constituents of a binary mixture formed of carbon and iron. We show that the packing density of the sample greatly affects the relative standard deviation of the emission lines. Furthermore, we show that the variation of the intensities of the C and Fe emission lines depends in a non-trivial way on the relative C–Fe concentration. The intensities of Fe neutral atomic lines behave differently than those of the ionic ones particularly at and above concentrations of 75%–80% Fe embedded in a carbon matrix. Unlike the emission from neutral Fe, those from ionic Fe yield a very sharp decrease followed by an equally strong increase of the emission lines over a relatively small range of relative concentration of C and Fe. To better investigate this effect, we have compared the results obtained with nanosecond-LIBS to those with femtosecond-LIBS and found that this phenomenon disappears. The physical interpretation of the sharp decrease followed by an equally sharp increase in the emission intensities from Fe ions as the concentration of Fe is increased requires more studies. - Highlights: ► The effects of the size of the particles on the fluctuations of the LIBS signals ► The variation of LIBS signals with the concentrations of Fe embedded in C is nontrivial. ► The intensities of neutral atomic lines can behave differently than those of ions

  1. CHEMICAL EVOLUTION OF THE UNIVERSE AT 0.7 < z < 1.6 DERIVED FROM ABUNDANCE DIAGNOSTICS OF THE BROAD-LINE REGION OF QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Sameshima, H. [Laboratory of Infrared High-resolution Spectroscopy, Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Yoshii, Y.; Kawara, K., E-mail: sameshima@cc.kyoto-su.ac.jp [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)

    2017-01-10

    We present an analysis of Mg ii λ 2798 and Fe ii UV emission lines for archival Sloan Digital Sky Survey (SDSS) quasars to explore the diagnostics of the magnesium-to-iron abundance ratio in a broad-line region cloud. Our sample consists of 17,432 quasars selected from the SDSS Data Release 7 with a redshift range of 0.72 <  z  < 1.63. A strong anticorrelation between the Mg ii equivalent width (EW) and the Eddington ratio is found, while only a weak positive correlation is found between the Fe ii EW and the Eddington ratio. To investigate the origin of these differing behaviors of Mg ii and Fe ii emission lines, we perform photoionization calculations using the Cloudy code, where constraints from recent reverberation mapping studies are considered. We find from calculations that (1) Mg ii and Fe ii emission lines are created at different regions in a photoionized cloud, and (2) their EW correlations with the Eddington ratio can be explained by just changing the cloud gas density. These results indicate that the Mg ii/Fe ii flux ratio, which has been used as a first-order proxy for the Mg/Fe abundance ratio in chemical evolution studies with quasar emission lines, depends largely on the cloud gas density. By correcting this density dependence, we propose new diagnostics of the Mg/Fe abundance ratio for a broad-line region cloud. In comparing the derived Mg/Fe abundance ratios with chemical evolution models, we suggest that α -enrichment by mass loss from metal-poor intermediate-mass stars occurred at z  ∼ 2 or earlier.

  2. Producción local, abastecimiento urbano y regulación municipal : el marco legal del vino en Bilbao (S. XIV-XVI

    Directory of Open Access Journals (Sweden)

    Ana María Rivera Medina

    2006-01-01

    Full Text Available En el presente trabajo pretendemos analizar la política intervencionista del Ayuntamiento de Bilbao, entre los siglos XIV y XVI, sobre el cultivo, producción y comercialización de vinos, tanto locales como foráneos, en un momento de transición: el paso de la Baja Edad Media al comienzo de la Modernidad. Intentaremos, igualmente, demostrar cómo el Ayuntamiento, máxima expresión del poder local, regula los distintos ámbitos de la viticultura, con el fin de proteger la producción local frente a la competencia de los vinos foráneos, con el propósito de lograr el abastecimiento de la Villa.The present article analyzes the interventionist politics of the City council of Bilbao, among the XIV and XVI centuries, on the cultivation, production and commercialization of wines, so much local as foreign, in a transition moment: the pass from the Late Middle Ages to the beginning of the Modern period. We will attempt, equally, to demonstrate how the City council, maximum expression of the local power, regulates the different environments of the viticulture, with the purpose of protecting the local production in front of the competition of the foreign wines, with the purpose of achieving the supply of the Villa.

  3. Magnetic, structural and electrical properties of ordered and disordered Co50Fe50 films

    International Nuclear Information System (INIS)

    Chen, Y.T.; Jen, S.U.; Yao, Y.D.; Wu, J.M.; Hwang, G.H.; Tsai, T.L.; Chang, Y.C.; Sun, A.C.

    2006-01-01

    Co 50 Fe 50 films with thickness varying from 100 to 500 A were deposited on a glass substrate by sputtering process, respectively. Two kinds of CoFe films were studied: one was the as-deposited film, and the other the annealed film. The annealing procedure was to keep the films at 400 deg. C for 5 h in a vacuum of 5x10 -6 mbar. From the X-ray study, we find that the as-deposited film prefers the CoFe(1 1 0) orientation. Moreover, the body-centered cubic (bcc) CoFe(1 1 0) line is split into two peaks: one corresponding to the ordered body-centered tetragonal (bct) phase, and the other, the disordered bcc phase. After annealing, the peak intensity of the ordered bct phase becomes much stronger, while that of the disordered bcc phase disappears. The annealing has also caused the ordered CoFe(2 0 0) line to appear. When the amount of the ordered bct phase in Co 50 Fe 50 is increased, the saturation magnetization (M s ) and coercivity (H c ) become larger, but the electrical resistivity (ρ) decreases. From the temperature coefficient of resistance (TCR) measurement, we learn that the bct grains in the CoFe film start to grow at temperature 82 deg. C

  4. Induction of apoptosis by Fe(salenCl through caspase-dependent pathway specifically in tumor cells

    Directory of Open Access Journals (Sweden)

    Nitika Pradhan

    2017-10-01

    Full Text Available Iron-based compounds possess the capability of inducing cell death due to their reactivity with oxidant molecules, but their specificity towards cancer cells and the mechanism of action are hitherto less investigated. A Fe(salenCl derivative has been synthesized that remains active in monomer form. The efficacy of this compound as an anti-tumor agent has been investigated in mouse and human leukemia cell lines. Fe(salenCl induces cell death specifically in tumor cells and not in primary cells. Mouse and human T-cell leukemia cell lines, EL4 and Jurkat cells are found to be susceptible to Fe(salenCl and undergo apoptosis, but normal mouse spleen cells and human peripheral blood mononuclear cells (PBMC remain largely unaffected by Fe(salenCl. Fe(salenCl treated tumor cells show significantly higher expression level of cytochrome c that might have triggered the cascade of reactions leading to apoptosis in cancer cells. A significant loss of mitochondrial membrane potential upon Fe(salenCl treatment suggests that Fe(salenCl induces apoptosis by disrupting mitochondrial membrane potential and homeostasis, leading to cytotoxity. We also established that apoptosis in the Fe(salenCl-treated tumor cells is mediated through caspase-dependent pathway. This is the first report demonstrating that Fe(salenCl can specifically target the tumor cells, leaving the primary cells least affected, indicating an excellent potential for this compound to emerge as a next-generation anti-tumor drug.

  5. Induction of apoptosis by Fe(salen)Cl through caspase-dependent pathway specifically in tumor cells.

    Science.gov (United States)

    Pradhan, Nitika; Pratheek, B M; Garai, Antara; Kumar, Ashutosh; Meena, Vikram S; Ghosh, Shyamasree; Singh, Sujay; Kumari, Shikha; Chandrashekar, T K; Goswami, Chandan; Chattopadhyay, Subhasis; Kar, Sanjib; Maiti, Prasanta K

    2014-10-01

    Iron-based compounds possess the capability of inducing cell death due to their reactivity with oxidant molecules, but their specificity towards cancer cells and the mechanism of action are hitherto less investigated. A Fe(salen)Cl derivative has been synthesized that remains active in monomer form. The efficacy of this compound as an anti-tumor agent has been investigated in mouse and human leukemia cell lines. Fe(salen)Cl induces cell death specifically in tumor cells and not in primary cells. Mouse and human T-cell leukemia cell lines, EL4 and Jurkat cells are found to be susceptible to Fe(salen)Cl and undergo apoptosis, but normal mouse spleen cells and human peripheral blood mononuclear cells (PBMC) remain largely unaffected by Fe(salen)Cl. Fe(salen)Cl treated tumor cells show significantly higher expression level of cytochrome c that might have triggered the cascade of reactions leading to apoptosis in cancer cells. A significant loss of mitochondrial membrane potential upon Fe(salen)Cl treatment suggests that Fe(salen)Cl induces apoptosis by disrupting mitochondrial membrane potential and homeostasis, leading to cytotoxity. We also established that apoptosis in the Fe(salen)Cl-treated tumor cells is mediated through caspase-dependent pathway. This is the first report demonstrating that Fe(salen)Cl can specifically target the tumor cells, leaving the primary cells least affected, indicating an excellent potential for this compound to emerge as a next-generation anti-tumor drug. © 2014 International Federation for Cell Biology.

  6. Identification of new fluorescence processes in the UV spectra of cool stars from new energy levels of Fe II and Cr II

    Science.gov (United States)

    Johansson, Sveneric; Carpenter, Kenneth G.

    1988-01-01

    Two fluorescence processes operating in atmospheres of cool stars, symbiotic stars, and the Sun are presented. Two emission lines, at 1347.03 and 1360.17 A, are identified as fluorescence lines of Cr II and Fe II. The lines are due to transitions from highly excited levels, which are populated radiatively by the hydrogen Lyman alpha line due to accidental wavelength coincidences. Three energy levels, one in Cr II and two in Fe II, are reported.

  7. Investigations of Deep-Level Fe-centres in Si by Mössbauer Spectroscopy

    CERN Multimedia

    Dietrich, M

    2002-01-01

    %IS359\\\\ \\\\Electronic, vibrational and diffusional properties of interstitial and substitutional Fe impurities in silicon are studied by $ ^{57} $Fe Mössbauer emission spectroscopy utilizing implanted radioactive $ ^{57}$Mn$^{+} $ parent ions from ISOLDE as probe atoms. Thus the electronic charge density and the impurity mean-square vibrational amplitude shall be determined for substitutional Fe$_{s} $ and for interstitial Fe$_{i}^{0/+} $ in its two different charge states. These quantities are complementary to previously determined hyperfine interaction parameters and are expected to shed light on the nature of the deviations between calculated and measured parameters. The supposedly different diffusivities of interstitial Fe$_{i}^{0} $ and Fe$_{i}^{+} $ shall be measured by the broadening of the Mössbauer lines, i.e. at a temperature where diffusion jumps occur on an atomic scale within the lifetime of the Mössbauer state.

  8. Fe-S Cluster Biogenesis in Isolated Mammalian Mitochondria

    Science.gov (United States)

    Pandey, Alok; Pain, Jayashree; Ghosh, Arnab K.; Dancis, Andrew; Pain, Debkumar

    2015-01-01

    Iron-sulfur (Fe-S) clusters are essential cofactors, and mitochondria contain several Fe-S proteins, including the [4Fe-4S] protein aconitase and the [2Fe-2S] protein ferredoxin. Fe-S cluster assembly of these proteins occurs within mitochondria. Although considerable data exist for yeast mitochondria, this biosynthetic process has never been directly demonstrated in mammalian mitochondria. Using [35S]cysteine as the source of sulfur, here we show that mitochondria isolated from Cath.A-derived cells, a murine neuronal cell line, can synthesize and insert new Fe-35S clusters into aconitase and ferredoxins. The process requires GTP, NADH, ATP, and iron, and hydrolysis of both GTP and ATP is necessary. Importantly, we have identified the 35S-labeled persulfide on the NFS1 cysteine desulfurase as a genuine intermediate en route to Fe-S cluster synthesis. In physiological settings, the persulfide sulfur is released from NFS1 and transferred to a scaffold protein, where it combines with iron to form an Fe-S cluster intermediate. We found that the release of persulfide sulfur from NFS1 requires iron, showing that the use of iron and sulfur for the synthesis of Fe-S cluster intermediates is a highly coordinated process. The release of persulfide sulfur also requires GTP and NADH, probably mediated by a GTPase and a reductase, respectively. ATP, a cofactor for a multifunctional Hsp70 chaperone, is not required at this step. The experimental system described here may help to define the biochemical basis of diseases that are associated with impaired Fe-S cluster biogenesis in mitochondria, such as Friedreich ataxia. PMID:25398879

  9. Mn and Fe Impurities in Si$_{1-x}$ Ge$_{x}$ alloys

    CERN Multimedia

    2002-01-01

    Following our investigations of Mn and Fe impurities in elemental semiconductors and in silicon in particular by means of on-line $^{57}$Fe Mössbauer spectroscopy, utilizing radioactive $^{57}$Mn$^{+}$ ion beams at ISOLDE, we propose to extend these studies to bulk and epitaxially-grown Si$_{1-x}$Ge$_{x}$ alloys. In these materials, although already successfully employed in electronic devices, little is known about point defects and important harmful 3d impurities. The experiments aim to determine a variety of fundamental properties: The lattice location of ion-implanted Mn/Fe, the electronic and vibrational properties of dilute Fe impurities in different lattice sites, the charge-state and composition dependence of the diffusivity of interstitial Fe on an atomic scale, the reactions and formation of complexes with lattice defects created by the $^{57}$Mn implantation or by the recoil effect in the nuclear decay to the Mössbauer state of $^{57m}$Fe. Feasibility studies in 2003 indicate that these aims can b...

  10. VizieR Online Data Catalog: New multiplet table for FeI (Nave+, 1994)

    Science.gov (United States)

    Nave, G.; Johansson, S.; Learner, R. C. M.; Thorne, A. P.; Brault, J. W.

    1995-02-01

    We have recorded spectra of iron-neon and iron-argon hollow cathode lamps in the region 1700A-5um (59,000-2000cm-1), with Fourier transform (FT) spectrometers at the National Solar Observatory, Tucson, Arizona, and Imperial College, London, UK, and with a high-resolution grating spectrograph at the National Institute of Standards and Technology, Gaithersburg, Maryland. The uncertainty of the strongest lines in the FT spectra is less than 0.002cm-1 (0.2mA at 3000A; 8mA at 2um). Pressure- and current-dependent shifts are less than 0.001cm-1 for transitions between low-lying levels, increasing to 0.006cm-1 for transitions between the most highly excited levels. We report 28 new energy levels of Fe I and revised values of another 818 levels. We have identified 9501 lines as due to 9759 transitions in Fe I, and these are presented in the form of a new multiplet table and finding list. This compares with the ~5500 lines due to 467 energy levels in the multiplet tables of Moore (1950, NBS Circ., No.488 and 1959, NBS Tech. note 30). The biggest increase is in the near-ultraviolet and near infrared, and many of the new lines are present in the solar spectrum. Experimental log (gf) values are included where they are available. A further 125 unidentified lines due to Fe I are given. (4 data files).

  11. Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating

    International Nuclear Information System (INIS)

    Brosius, Jeffrey W.; Daw, Adrian N.; Rabin, D. M.

    2014-01-01

    We present spatially resolved EUV spectroscopic measurements of pervasive, faint Fe XIX 592.2 Å line emission in an active region observed during the 2013 April 23 flight of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-13) sounding rocket instrument. With cooled detectors, high sensitivity, and high spectral resolution, EUNIS-13 resolves the lines of Fe XIX at 592.2 Å (formed at temperature T ≈ 8.9 MK) and Fe XII at 592.6 Å (T ≈ 1.6 MK). The Fe XIX line emission, observed over an area in excess of 4920 arcsec 2 (2.58 × 10 9 km 2 , more than 60% of the active region), provides strong evidence for the nanoflare heating model of the solar corona. No GOES events occurred in the region less than 2 hr before the rocket flight, but a microflare was observed north and east of the region with RHESSI and EUNIS during the flight. The absence of significant upward velocities anywhere in the region, particularly the microflare, indicates that the pervasive Fe XIX emission is not propelled outward from the microflare site, but is most likely attributed to localized heating (not necessarily due to reconnection) consistent with the nanoflare heating model of the solar corona. Assuming ionization equilibrium we estimate Fe XIX/Fe XII emission measure ratios of ∼0.076 just outside the AR core and ∼0.59 in the core.

  12. Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating

    Energy Technology Data Exchange (ETDEWEB)

    Brosius, Jeffrey W. [Catholic University of America at NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States); Daw, Adrian N. [NASA Goddard Space Flight Center, Solar Physics Laboratory, Code 671, Greenbelt, MD 20771 (United States); Rabin, D. M., E-mail: Jeffrey.W.Brosius@nasa.gov [NASA Goddard Space Flight Center, Heliophysics Science Division, Code 670, Greenbelt, MD 20771 (United States)

    2014-08-01

    We present spatially resolved EUV spectroscopic measurements of pervasive, faint Fe XIX 592.2 Å line emission in an active region observed during the 2013 April 23 flight of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-13) sounding rocket instrument. With cooled detectors, high sensitivity, and high spectral resolution, EUNIS-13 resolves the lines of Fe XIX at 592.2 Å (formed at temperature T ≈ 8.9 MK) and Fe XII at 592.6 Å (T ≈ 1.6 MK). The Fe XIX line emission, observed over an area in excess of 4920 arcsec{sup 2} (2.58 × 10{sup 9} km{sup 2}, more than 60% of the active region), provides strong evidence for the nanoflare heating model of the solar corona. No GOES events occurred in the region less than 2 hr before the rocket flight, but a microflare was observed north and east of the region with RHESSI and EUNIS during the flight. The absence of significant upward velocities anywhere in the region, particularly the microflare, indicates that the pervasive Fe XIX emission is not propelled outward from the microflare site, but is most likely attributed to localized heating (not necessarily due to reconnection) consistent with the nanoflare heating model of the solar corona. Assuming ionization equilibrium we estimate Fe XIX/Fe XII emission measure ratios of ∼0.076 just outside the AR core and ∼0.59 in the core.

  13. Curves of growth of spectral lines emitted by a laser-induced plasma: influence of the temporal evolution and spatial inhomogeneity of the plasma

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, J.A.; Bengoechea, J.; Aragon, C. E-mail: carlos.aragon@unavarra.es

    2003-02-03

    The curves of growth (COG) of five Fe I lines emitted from a laser-induced plasma, generated with Fe-Ni alloys in air at atmospheric pressure, have been investigated. Spectral lines with different energy levels and line widths, emitted with a broad range of optical depths, have been included in the study in order to check the validity of theoretical models proposed for COG generation, based in the radiative transfer within a plasma in local thermodynamic equilibrium. The COGs have been measured at time windows of 4-5 {mu}s and 15-18 {mu}s. The Stark widths of the Fe I lines have been obtained, and the line widths have been determined by measuring the plasma electron density at the time windows selected. It is shown that at a time window of 4-5 {mu}s, the inhomogeneity of the plasma magnitudes has an important influence on the COGs of intense lines. For this time window, a two-region model of the plasma has been used to generate theoretical COGs that describe satisfactorily the experimental curves of all the lines using a single set of plasma parameters. The results reveal the existence of considerable gradients between the inner and the outer plasma regions in the temperature (9400-7800 K) and in the density of Fe atoms (4x10{sup 16}-0.02x10{sup 16} cm{sup -3} for a sample with 100% Fe). On the contrary, at the time window 15-18 {mu}s, at which the plasma has suffered most of its expansion and cooling process, the COGs of all the lines may be described by a single-region model, corresponding to a plasma with uniform temperature (6700 K) and density of Fe atoms (0.06x10{sup 16} cm{sup -3} for a sample with 100% Fe). It is also shown that at initial times, the plasma inhomogeneity has an important effect in the line profiles of intense spectral lines, which are described by using the two-region model of the laser-induced plasma.

  14. Theory of Moessbauer line broadening due to diffusion

    International Nuclear Information System (INIS)

    Schroeder, K.; Wolf, D.; Dederichs, P.H.

    1981-12-01

    We have calculated the line broadening of the Moessbauer line due to diffusion of Moessbauer atoms via single vacanices. We take into account the perturbation of vacancy jumps in the neighbourhood of an impurity Moessbauer atom (e.g. Fe in Al) using the 5-frequency model. The anisotropy of the line width is given by the Fourier transform of the final distribution of a Moessbauer atom after an encounter with a vacancy. This distribution is calculated by Monte Carlo computer simulation. 3 figures, 1 tables

  15. Preparation of Fe3O4 magnetic nanoparticles coated with gallic acid for drug delivery

    Science.gov (United States)

    Dorniani, Dena; Hussein, Mohd Zobir Bin; Kura, Aminu Umar; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

    2012-01-01

    Background and methods Magnetic iron oxide nanoparticles were prepared using a sonochemical method under atmospheric conditions at a Fe2+ to Fe3+ molar ratio of 1:2. The iron oxide nanoparticles were subsequently coated with chitosan and gallic acid to produce a core-shell structure. Results X-ray diffraction demonstrated that the magnetic nanoparticles were pure Fe3O4 with a cubic inverse spinel structure. Transmission electron microscopy showed that the Fe3O4 nanoparticles were of spherical shape with a mean diameter of 11 nm, compared with 13 nm for the iron oxide-chitosan-gallic acid (FCG) nanocarriers. Conclusion The magnetic nanocarrier enhanced the thermal stability of the drug, gallic acid. Release of the active drug from the FCG nanocarrier was found to occur in a controlled manner. The gallic acid and FCG nanoparticles were not toxic in a normal human fibroblast (3T3) line, and anticancer activity was higher in HT29 than MCF7 cell lines. PMID:23166439

  16. Using Fe XXII to Determine the Electron Density of Stellar Coronae

    Science.gov (United States)

    Lepson, Jaan; Beiersdorfer, P.; Brown, G. V.; Clementson, J.; Gu, M. F.

    2010-03-01

    Lines from Fe XXII, both in the EUV and X-ray region, are known to be sensitive to the electron density and have in recent years been used as diagnostics of stellar coronae, such as AB Dor and Ex Hya. We have recently obtained spectral data from laboratory sources in which the electron density is known either from non-spectroscopic means or from K-shell density diagnostics. The densities of the laboratory sources range from 5x1011 cm-3 to 5x1014 cm-3. The measurements have been used to test the spectral models underlying the Fe XXII density diagnostic line ratios. This work was supported by the NASA APRA program and the DOE General Plasma Science program.

  17. Gamma ray production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb at 90 deg

    International Nuclear Information System (INIS)

    Zhou Hongyu; Tang Lin; Yan Yiming

    1986-11-01

    Discrete γ-ray spectra and production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb targets have been measured at 90 deg. using a 110.7cm 3 Ge(Li) detector. A single γ-ray peak was measured for C. For Al 34 γ lines, for Fe 41 γ lines, for V 61 γ lines and for Nb 79 γ lines were measured

  18. Rectifiability of Line Defects in Liquid Crystals with Variable Degree of Orientation

    Science.gov (United States)

    Alper, Onur

    2018-04-01

    In [2], H ardt, L in and the author proved that the defect set of minimizers of the modified Ericksen energy for nematic liquid crystals consists locally of a finite union of isolated points and Hölder continuous curves with finitely many crossings. In this article, we show that each Hölder continuous curve in the defect set is of finite length. Hence, locally, the defect set is rectifiable. For the most part, the proof closely follows the work of D e L ellis et al. (Rectifiability and upper minkowski bounds for singularities of harmonic q-valued maps, arXiv:1612.01813, 2016) on harmonic Q-valued maps. The blow-up analysis in A lper et al. (Calc Var Partial Differ Equ 56(5):128, 2017) allows us to simplify the covering arguments in [11] and locally estimate the length of line defects in a geometric fashion.

  19. Absorber transmissivities in 57Fe Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Ballet, O.

    1985-01-01

    Some useful relations are derived for the polarization dependent optical index of 57 Fe Moessbauer absorbers. Real rotation matrices are extensively used and, besides wave-direction dependence, their properties simplify also the treatment of texture and f-anisotropy. The derivation of absorber transmissivities from the optical index is discussed with a special emphasis on line overlapping. (Auth.)

  20. Vortex dynamics and irreversibility line in optimally doped SmFeAsO0.8F0.2 from ac susceptibility and magnetization measurements

    Science.gov (United States)

    Prando, G.; Carretta, P.; de Renzi, R.; Sanna, S.; Palenzona, A.; Putti, M.; Tropeano, M.

    2011-05-01

    Ac susceptibility and static magnetization measurements were performed in the optimally doped SmFeAsO0.8F0.2 superconductor. The field-temperature phase diagram of the superconducting state was drawn, and, in particular, the features of the flux lines were derived. The dependence of the intragrain depinning energy on the magnetic field intensity was derived in the thermally activated flux-creep framework, enlightening a typical 1/H dependence in the high-field regime. The intragrain critical current density was extrapolated in the zero-temperature and zero-magnetic-field limit, showing a remarkably high value Jc0(0)~2×107 A/cm2, which demonstrates that this material is rather interesting for potential future technological applications.

  1. MFM study of NdFeB and NdFeB/Fe/NdFeB thin films

    International Nuclear Information System (INIS)

    Gouteff, P.C.; Folks, L.; Street, R.

    1998-01-01

    Domain structures of NdFeB thin films, ranging in thickness between 1500 and 29 nm, have been studied qualitatively by magnetic force microscopy (MFM). Samples were prepared using a range of sputtering conditions resulting in differences in properties such as texture, coercivity and magnetic saturation. MFM images of all the films showed extensive interaction domain structures, similar to those observed in nanocrystalline bulk NdFeB. An exchange-coupled NdFeB/Fe/NdFeB trilayer with layer thicknesses 18 nm/15 nm/18 nm, respectively, was also examined using MFM. (orig.)

  2. THE 2014 MARCH 29 X-FLARE: SUBARCSECOND RESOLUTION OBSERVATIONS OF Fe XXI λ1354.1

    Energy Technology Data Exchange (ETDEWEB)

    Young, Peter R. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Tian, Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jaeggli, Sarah [Department of Physics, Montana State University, P.O. Box 173840, Bozeman, MT 59717 (United States)

    2015-02-01

    The Interface Region Imaging Spectrometer (IRIS) is the first solar instrument to observe ∼10 MK plasma at subarcsecond spatial resolution through imaging spectroscopy of the Fe XXI λ1354.1 forbidden line. IRIS observations of the X1 class flare that occurred on 2014 March 29 at 17:48 UT reveal Fe XXI emission from both the flare ribbons and the post-flare loop arcade. Fe XXI appears at all of the chromospheric ribbon sites, although typically with a delay of one raster (75 s) and sometimes offset by up to 1''. 100-200 km s{sup –1} blue-shifts are found at the brightest ribbons, suggesting hot plasma upflow into the corona. The Fe XXI ribbon emission is compact with a spatial extent of <2'', and can extend beyond the chromospheric ribbon locations. Examples are found of both decreasing and increasing blue-shift in the direction away from the ribbon locations, and blue-shifts were present for at least six minutes after the flare peak. The post-flare loop arcade, seen in Atmospheric Imaging Assembly 131 Å filtergram images that are dominated by Fe XXI, exhibited bright loop-tops with an asymmetric intensity distribution. The sizes of the loop-tops are resolved by IRIS at ≥1'', and line widths in the loop-tops are not broader than in the loop-legs suggesting the loop-tops are not sites of enhanced turbulence. Line-of-sight speeds in the loop arcade are typically <10 km s{sup –1}, and mean non-thermal motions fall from 43 km s{sup –1} at the flare peak to 26 km s{sup –1} six minutes later. If the average velocity in the loop arcade is assumed to be at rest, then it implies a new reference wavelength for the Fe XXI line of 1354.106 ± 0.023 Å.

  3. New thermodynamic measurements in the U-fe system

    Energy Technology Data Exchange (ETDEWEB)

    Labroche, D.; Dugne, O. [CEA Vallee du Rhone, Dept. de Technologie de l' Enrichissement, 26 - Pierrelatte (France); Rogez, J. [CTM, 13 - Marseille (France)

    2001-07-01

    The U-Fe phase diagram data from thermal measurements by Gordon, Grogan, Chapman and Michaud and from mass spectroscopic measurements by Gardie are generally in agreement. Two line compounds UFe{sub 2} and U{sub 6}Fe exist. The enthalpy of formation of UFe{sub 2} at 298 K is reported to be -32.4 kJ/mol by Akhachinskij, -61.8 kJ/mol by Kanno and -42.03 kJ/mol by Antony. This disagreement between the different authors requires some new measurements in order to improve the knowledge of this system. Moreover no data exists on the enthalpy of formation of U{sub 6}Fe and on the heat capacity of these two materials. The objective of this study is to measure these missing data in view of performing an assessment of the phase diagram. (author)

  4. Observations of the X-ray nova A0620-00 with the Ariel V crystal spectrometer/polarimeter

    International Nuclear Information System (INIS)

    Griffiths, R.E.; Rickets, M.J.; Cooke, B.A.

    1976-01-01

    The X-ray nova A0620-00 has been studied with the Ariel V crystal spectrometer/polarimeter for the presence of X-ray lines and polarization. Upper limits are obtained for the Si XIV, S XV and S XVI lines to a level of less than 2 eV at 3 sigma for the sulphur lines and 3.6 eV for Si XIV. No linear polarization is observed to a level of 2 per cent at 2.6 keV. These results are interpreted in terms of an accretion disk model for the source, in which the electron scattering depth tausub(es) approximately 20, and constraints are given on the disk geometry. (author)

  5. Preparation and Mechanical Properties of TiC-Fe Cermets and TiC-Fe/Fe Bilayer Composites

    Science.gov (United States)

    Zheng, Yong; Zhou, Yang; Li, Runfeng; Wang, Jiaqi; Chen, Lulu; Li, Shibo

    2017-10-01

    TiC-Fe cermets and TiC-Fe/Fe bilayer composites consisting of a pure Fe layer and a TiC-Fe cermets layer were fabricated by hot-pressing sintering. The pure Fe layer contributes to the toughness of composites, and the TiC-Fe cermets layer endows the composites with an improved tensile strength and hardness. The effect of TiC contents (30-60 vol.%) on the mechanical properties of TiC-Fe cermets and TiC-Fe/Fe bilayer composites was investigated. Among the TiC-Fe cermets, the 40 vol.% TiC-Fe cermets possessed the highest tensile strength of 581 MPa and Vickers hardness of 5.1 GPa. The maximum fracture toughness of 17.0 MPa m1/2 was achieved for the TiC-Fe cermets with 30 vol.% TiC. For the TiC-Fe/Fe bilayer composites, the 40 vol.% TiC-Fe/Fe bilayer composite owns the maximum tensile strength of 588 MPa, which is higher than that of 40 vol.% TiC-Fe cermets. In addition, the 33.5% increment of tensile strength of 30 vol.% TiC-Fe/Fe bilayer composite comparing with the 30 vol.% TiC-Fe cermets, which is attributed to the 30 vol.% TiC-Fe/Fe bilayer composite exhibited the largest interlaminar shear strength of 335 MPa. The bilayer composites are expected to be used as wear resistance components in some heavy wear conditions.

  6. Manganese Abundances in the Stars with Metallicities -1 <[Fe/H]< +0.3

    Science.gov (United States)

    Mishenina, T.; Gorbaneva, T.; Pignatari, M.; Thielemann, F.-K.; Korotin, S.

    2018-01-01

    We estimate the Mn abundances in the atmospheres of 247 F-G-K-type dwarf stars belonging to the thin and thick disk populations in the metallicity range -1 LTE approximation; the synthetic spectrum for the Mn lines was computed accounting for the hyperfine structure. Starting from the results obtained, we discuss the evolution of the [Mn/Fe] ratio with respect to [Fe/H] in the galactic disk.

  7. Discovery of New Coronal Lines at 2.843 and 2.853 μm

    Science.gov (United States)

    Samra, Jenna E.; Judge, Philip G.; DeLuca, Edward E.; Hannigan, James W.

    2018-04-01

    Two new emission features were observed during the 2017 August 21 total solar eclipse by a novel spectrometer, the Airborne Infrared Spectrometer (AIR-Spec), flown at 14.3 km altitude aboard the NCAR Gulfstream-V aircraft. We derive wavelengths in air of 2.8427 ± 0.00009 μm and 2.8529 ± 0.00008 μm. One of these lines belongs to the 3{{{p}}}53{{d}}{}3{{{F}}}3^\\circ \\to 3{{{p}}}53{{d}}{}3{{{F}}}4^\\circ transition in Ar-like Fe IX. This appears to be the first detection of this transition from any source. Minimization of residual wavelength differences using both measured wavelengths, together with National Institute of Standards and Technology (NIST) extreme ultraviolet wavelengths, does not clearly favor assignment to Fe IX. However, the shorter wavelength line appears more consistent with other observed features formed at similar temperatures to Fe IX. The transition occurs between two levels within the excited 3{{{p}}}53{{d}} configuration, 429,000 cm‑1 above the ground level. The line is therefore absent in photo-ionized coronal-line astrophysical sources such as the Circinus Galaxy. Data from a Fourier transform interferometer (FTIR) deployed from Wyoming show that both lines are significantly attenuated by telluric H2O, even at dry sites. We have been unable to identify the longer wavelength transition.

  8. Magnetic Compton scattering study of Laves phase ZrFe2 and Sc doped ZrFe2: Experiment and Green function based relativistic calculations

    Science.gov (United States)

    Bhatt, Samir; Mund, H. S.; Kumar, Kishor; Bapna, Komal; Dashora, Alpa; Itou, M.; Sakurai, Y.; Ahuja, B. L.

    2018-05-01

    Spin momentum densities of ferromagnetic ZrFe2 and Zr0.8Sc0.2Fe2 have been measured using magnetic Compton scattering with 182.65 keV circularly polarized synchrotron radiations. Site specific spin moments, which are responsible for the formation of total spin moment, have been deduced from Compton line shapes. At room temperature, the computed spin moment of ZrFe2 is found to be slightly higher than that of Sc doped ZrFe2 which is in consensus with the magnetization data. To compare the experimental data, we have also computed magnetic Compton profiles (MCPs), total and partial spin projected density of states (DOS) and the site specific spin moments using spin-polarized relativistic Korringa-Kohn-Rostoker method. It is observed that the spin moment at Fe site is aligned antiparallel to that of Zr site in both ZrFe2 and Zr0.8Sc0.2Fe2. The MCP results when compared with vibrating sample magnetometer based magnetization data, show a very small contribution of orbital moment in the formation of total magnetic moments in both the compounds. The DOS of ferromagnetic ground state of ZrFe2 and Zr0.8Sc0.2Fe2 are interpreted on the basis of a covalent magnetic model beyond the Stoner rigid band model. It appears that on alloying between a magnetic and a non-magnetic partner (with low valence), a polarization develops on the non-magnetic atom which is anti-parallel to that of the magnetic atom.

  9. Spectroscopy of peaks at microwave range for nanostructure SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} ferrite particles

    Energy Technology Data Exchange (ETDEWEB)

    Ariaee, Sina, E-mail: sina.ariaee@tabrizu.ac.ir; Mehdipour, Mostafa, E-mail: Mostafa_mehdipour67@yahoo.com; Moradnia, Mina, E-mail: mina.moradnia86@gmail.com

    2017-05-01

    In this paper, (SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4}) nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts utilizing the sodium hydroxide solution. The resulting precursors were heat-treated at 1100 °C for 4 h. After cooling in the furnace, the ferrite powders were pressed at 0.1 MPa and then sintered at 1200 °C for 4 h. The spectroscopy and characterization of peaks at the microwave range (X-band) for the nanostructure ferrite particles were investigated by the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. The extracted data from these theoretical and experimental results showed that the natural ferromagnetic resonance can be lead to the narrow peaks and the width of the peaks can be related to the periodic effects. Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); the narrow peak at (9.8 GHz) was remaining unchanged and consistent while the wide one was shifted from 11 GHz to 8.5 GHz by decreasing the thickness of the samples. These phenomena were also happened for SrFe{sub 12}O{sub 19} samples. The natural resonance was not happened due to the hard magnetic properties of these nano structure particles. - Highlights: • SrFe{sub 12}O{sub 19} and NiFe{sub 2}O{sub 4} nanostructure ferrite particles were synthesized via the co-precipitation of chloride salts. • Two kinds of peaks were seen for NiFe{sub 2}O{sub 4} at X-band (8–12 GHz); these phenomena were also happened for SrFe{sub 12}O{sub 19} samples. • The narrow peaks were remained unchanged and consistent while the wide ones were shifted by decreasing the thickness of the samples. • Characterization procedure was conducted utilizing the ferromagnetic resonance/transmit-line theories and Reflection Loss (RL) plots. • It was concluded that the natural ferromagnetic resonance can be lead to the narrow peaks while the wide ones can be related to the periodic effects.

  10. Proceedings of XIV Workshop on Nuclear Physics. VIII International Symposium on Nuclear and Related Techniques. WONP-NURT 2013

    International Nuclear Information System (INIS)

    2013-02-01

    This year 2013, the XIV Workshop on Nuclear Physics and VIII International Symposium on Nuclear and Related Techniques, WONP-NURT 2013 organized by the Center of Technological Applications and Nuclear Development from 5 to 8 February at the National Museum of Fine Arts. NURT is one of the key Cuban scientific meetings since 1997 dealing with the peaceful applications of nuclear techniques in several domains of the society. WONP and NURT provide an unique opportunity for the national and international scientific community to meet outstanding researchers and discuss current trends in several areas of theoretical, experimental and applied nuclear physics and related topics. The papers submitted to this event are presented in this CD-ROM

  11. Synthesis of Cd/(Al+Fe) layered double hydroxides and characterization of the calcination products

    International Nuclear Information System (INIS)

    Perez, M.R.; Barriga, C.; Fernandez, J.M.; Rives, V.; Ulibarri, M.A.

    2007-01-01

    Layered double hydroxides (LDHs) containing Cd(II), Al(III), and Fe(III) in the brucite-like layers with different starting Fe/Al atomic ratios and with nitrate as counteranion have been prepared following the coprecipitation method at a constant pH value of 8. An additional Cd(II),Al(III)-LDH sample interlayered with hexacyanoferrate(III) ions has been prepared by ionic exchange at pH 9. The samples have been characterized by elemental chemical analysis, powder X-ray diffraction (PXRD), and FT-IR spectroscopy. Their thermal stability has been assessed by thermogravimetric and differential thermal analyses (TG-DTA) and mass spectrometric analysis of the evolved gases. The PXRD patterns of the solids calcined at 800 deg. C show diffraction lines corresponding to Cd(Al)O and spinel-type materials, which precise nature (CdAl 2 O 4 , Cd 1-x Fe 2+x O 4 , or Cd x Fe 2.66 O 4 ) depends on location and concentration of iron in the parent material or precursor. - Graphical abstract: Layered double hydroxides (LDHs) containing Cd(II), Al(III), and Fe(III) in the brucite-like layers with different starting Fe/Al atomic ratios and with nitrate as counteranion have been prepared following the coprecipitation method. An additional Cd(II),Al(III)-LDH sample interlayered with hexacyanoferrate(III) ions has been prepared by ionic exchange. Calcination at 800 deg. C shows diffraction lines corresponding to CdO and to spinel-type materials. SEM micrograph of sample CdAlFe-N-0

  12. Fe atom exchange between aqueous Fe2+ and magnetite.

    Science.gov (United States)

    Gorski, Christopher A; Handler, Robert M; Beard, Brian L; Pasakarnis, Timothy; Johnson, Clark M; Scherer, Michelle M

    2012-11-20

    The reaction between magnetite and aqueous Fe(2+) has been extensively studied due to its role in contaminant reduction, trace-metal sequestration, and microbial respiration. Previous work has demonstrated that the reaction of Fe(2+) with magnetite (Fe(3)O(4)) results in the structural incorporation of Fe(2+) and an increase in the bulk Fe(2+) content of magnetite. It is unclear, however, whether significant Fe atom exchange occurs between magnetite and aqueous Fe(2+), as has been observed for other Fe oxides. Here, we measured the extent of Fe atom exchange between aqueous Fe(2+) and magnetite by reacting isotopically "normal" magnetite with (57)Fe-enriched aqueous Fe(2+). The extent of Fe atom exchange between magnetite and aqueous Fe(2+) was significant (54-71%), and went well beyond the amount of Fe atoms found at the near surface. Mössbauer spectroscopy of magnetite reacted with (56)Fe(2+) indicate that no preferential exchange of octahedral or tetrahedral sites occurred. Exchange experiments conducted with Co-ferrite (Co(2+)Fe(2)(3+)O(4)) showed little impact of Co substitution on the rate or extent of atom exchange. Bulk electron conduction, as previously invoked to explain Fe atom exchange in goethite, is a possible mechanism, but if it is occurring, conduction does not appear to be the rate-limiting step. The lack of significant impact of Co substitution on the kinetics of Fe atom exchange, and the relatively high diffusion coefficients reported for magnetite suggest that for magnetite, unlike goethite, Fe atom diffusion is a plausible mechanism to explain the rapid rates of Fe atom exchange in magnetite.

  13. The Moessbauer effect in Fe(III) HEDTA, Fe(III) EDTA, and Fe(III) CDTA compounds

    International Nuclear Information System (INIS)

    Prado, F.R.

    1989-01-01

    The dependence of Moessbauer spectra with pH value of Fe(III)HEDTA and Fe(III)CDTA compounds is studied. Informations on formation processes of LFe-O-FeL (L=ligand) type dimers by the relation of titration curves of Fe(III)EDTA, Fe(III)HEDTA and Fe(III)CDTA compounds with the series of Moessbauer spectra, are obtained. Some informations on Fe-O-Fe bond structure are also obtained. Comparing the titration curves with the series of Moessbauer spectra, it is concluded that the dimerization process begins when a specie of the form FeXOH α (X = EDTA, HEDTA, CDTA; α = -1, -2) arises. (M.C.K.) [pt

  14. Francesc Eiximenis y su época: finales del siglo XIV y principios del siglo XV

    Directory of Open Access Journals (Sweden)

    Pedro SANTONJA

    2009-11-01

    Full Text Available Durante el siglo XIV se producen algunos de los episodios más controvertidos de la historiografía: el tránsito de la economía feudal a la economía precapitalista, el cambio de una sociedad eminentemente rural a una sociedad urbana y mercantil, el nacimiento de una burguesía poderosa y culta, y la evolución de la cultura monástica, escriturística y contemplativa, a la cultura conventual, especulativa y escolástica. La edad de oro de la filosofía y de la teología llamadas «escolásticas», que florecieron, efectivamente, en las escuelas, coincide más bien con el período que se extiende aproximadamente entre 1228, comienzo de la enseñanza de Alberto Magno en Colonia, hasta 1350, fecha de la muerte de Guillermo de Ockam.

  15. Effectiveness of FeEDDHA, FeEDDHMA, and FeHBED in Preventing Iron-Deficiency Chlorosis in Soybean.

    Science.gov (United States)

    Bin, Levi M; Weng, Liping; Bugter, Marcel H J

    2016-11-09

    The performance of FeHBED in preventing Fe deficiency chlorosis in soybean (Glycine max (L.) Merr.) in comparison to FeEDDHA and FeEDDHMA was studied, as well as the importance of the ortho-ortho and ortho-para/rest isomers in defining the performance. To this end, chlorophyll production (SPAD), plant dry matter yield, and the mass fractions of important mineral elements in the plant were quantified in a greenhouse pot experiment. All three Fe chelates increased SPAD index and dry matter yield compared to the control. The effect of FeHBED on chlorophyll production was visible over a longer time span than that of FeEDDHA and FeEDDHMA. Additionally, FeHBED did not suppress Mn uptake as much as the other Fe chelates. Compared to the other Fe chelates, total Fe content in the young leaves was lower in the FeHBED treatment; however, total Fe content was not directly related to chlorophyll production and biomass yield. For each chelate, the ortho-ortho isomer was found to be more effective than the other isomers evaluated.

  16. NMR measurements in milled RE-TM2 compounds (RE=Gd and TM=Co, Fe)

    International Nuclear Information System (INIS)

    Tribuzy, C.V.; Guimaraes, A.P.; Biondo, A.; Larica, C.; Alves, K.M.B.

    1996-09-01

    Milled samples of the Laves phase intermetallic compounds Gd Fe 2 and Gd CO 2 were measured by NMR at 4.2 K. The milling was made from the crystalline intermetallic compounds, inside a cylindrical tool made of hard steel, under argon atmosphere, for several different time intervals. The initial compounds were produced from high purity elements in an arc furnace, under inert atmosphere. Their X-ray diffraction patterns agreed with those of the literature. The milling of Gd Fe 2 and of Gd CO 2 , induces amorphization. Above 1 hour the milling of Gd Fe 2 leads to segregation of α-Fe and formation of a Gd-Fe phase. These results are shown in the X-ray analysis. The spin-echo pulse NMR technique was utilized to study some structural and magnetic as a function of milling time. The measurements were made in a broad band pulse NMR spectrometer. The NMR spectra of the 155 Gd 157 Gd isotopes in Gd Fe 2 show a broadening and displacement of the NMR lines, reflecting the introduction of defects, some kind of disorder and also the formation of a new Gd-rich phase after 1 hour. This result is in agreement with the X-ray spectra. In both systems, the spectra of the amorphous samples show broader lines, and the measured hyperfine fields do not change much with milling. (author). 9 refs., 4 figs

  17. Internal Displacement Reactions in Multicomponent Oxides: Part I. Line Compounds with Narrow Homogeneity Range

    OpenAIRE

    Reddy, SNS; Leonard, DN; Wiggins, LB; Jacob, KT

    2005-01-01

    As a model of an internal displacement reaction involving a ternary oxide line compound, the following reaction was studied at 1273 K as a function of time, t: $Fe+NiTiO_3 = Ni + FeTiO_3$ Both polycrystalline and single-crystal materials were used as the starting $NiTiO_3$ oxide. During the reaction, the Ni in the oxide compound is displaced by Fe and it precipitates as a \\gamma -(Ni-Fe) alloy. The reaction preserves the starting ilmenite structure. The product oxide has a consta...

  18. Possibility for using of two Paulownia lines as a tool for remediation of heavy metal contaminated soil.

    Science.gov (United States)

    Tzvetkova, Nikolina; Miladinova, Kamelya; Ivanova, Katya; Georgieva, Teodora; Geneva, Marya; Markovska, Yuliana

    2015-01-01

    One-year-old two Paulownia lines (Ptomentosa x fortunei--TF 01 and R elongata x fortunei--EF 02) were grown, as pot experiment, in soil collected from the field of waste depository of Kremikovtzi ferrous metallurgical industry near Sofia. The soil was heavily polluted with Cd. Metals content (Ca, Mg, K, Na, Cd, Cu, Pb, Zn and Fe) in soil and its distribution in roots, stems and leaves of both lines was studied. The results showed that Ca and K accumulated more in stem, Mg, Na, Fe and Cd in root, while Pb, Cu and Zn in the leaves of both lines. The bloaccumulation factor (BF) and translocation factor (TF) were evaluated in order to determine the potential of plants in removing metals from contaminated soil. The BF for Fe, Pb, Cu and Zn in TF 01 line exceeded that of EF 02 line--5.6; 1.03; 1.20; 1.14 times, respectively. TF was higher in TF 01 line for Fe, Pb and Cd (6.0; 1.92 and 1.03, respectively), but not for Cu and Zn. The success of phytoremediation depends on plant growth and restricted distribution of heavy metals in shoots. Our results showed that stem length and total leaf area of Paulownia elongata x fortunei were higher than Paulownia tomentosa x fortuneibut BF for Cu and Zn and TF for Pb was less. BF for Cd was 1.7 times higher and TF for Zn was 1.03 times higher in Paulownia elongata x fortunei. Selected two lines (P. tomentosa x fortunei--TF 01 and P elongataxfortunei--EF02) were accumulators of Cu, Zn and Cd. Paulownia tomentosax fortunei accumulated more Pb and Zn in aboveground parts, while Paulownia elongata x fortunei--accumulated Zn only. These lines proved to be a promising species for phytoremediation of heavy metal polluted soils due to high biomass productivity.

  19. The effect of cooking and washing rice on the bio-accessibility of As, Cu, Fe, V and Zn using an on-line continuous leaching method.

    Science.gov (United States)

    Horner, Nolan S; Beauchemin, Diane

    2013-01-03

    A previously developed method based on continuous on-line leaching with artificial gastro-intestinal fluids was used to determine the bio-accessible fraction of As, Cu, Fe, V and Zn in brown and white rice from California by inductively coupled mass spectrometry (ICP-MS). Saliva generally accounted for the largest percentage of total element leached in comparison to gastric and intestinal juices. Arsenic speciation analysis was performed on the saliva and gastric juice leachates using ion exchange chromatography coupled to ICP-MS. The four most toxic species of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)), as well as Cl(-) in the gastric juice leachate, were successfully separated within 5.5min using a simple nitric acid gradient. While cooking rice had relatively little effect on total bio-accessibility, a change in species from As(V) and DMA to As(III) was observed for both types of rice. On the other hand, washing the rice with doubly deionized water prior to cooking removed a large percentage of the total bio-accessible fraction of As, Cu, Fe, V and Zn. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. The constructive process in the Cimorro zone in the the Cathedral of Avila, (century XII-XIV. Hypothesis and its verification through the analysis of Structural Stability Smart and Sustainable Offices (SSO

    Directory of Open Access Journals (Sweden)

    Mª A. Benito Pradillo

    2018-01-01

    Full Text Available This paper presents a hypothesis about the order in the constructive process for the head zone in the Cathedral of Ávila, called Cimorro. The hypothesis proposed in this area considers for its construction three different stages: XII Century, XIII Century and XIV Century. The proposed hypotesis have been verified with the Analysis of Stability realised. The theoretical Framework used is the Limit Analysis to Masonry Structures. After prooving the Structural Stability for each of the building stages, the following conclusions are made: Through the XII Century, the possibility of closing the central vault without Buttress System for a short period of time and the subsequent placement of a tribune is stated. A fortification formed by the barbican and the «adarves» were built during the XIII Century. In the XIV Century, the tribune is removed and replaced with the Buttress System with buttress and double flying buttress, which we can see nowadays.

  1. Structure of Fe(III) precipitates generated by Fe(0) electrocoagulation in the presence of groundwater ions

    Science.gov (United States)

    van Genuchten, C. M.; Pena, J.; Addy, S. E.; Gadgil, A. J.

    2012-12-01

    -ranged atomic pair correlations as 2-line ferrihydrite (2LFH), rather than lepidocrocite (Lp) which is generated in an NaCl electrolyte. However, when Ca or Mg is added to oxyanion electrolytes, Fe-Fe polymerization and particle size both tend to increase and a Lp-like material with characteristic Fe-O and Fe-Fe pair correlations is once again favored. The presence of either Ca or Mg also enhances the removal P, As(V), and to a lesser extent, Si per mass of Fe. The analysis from EXAFS and PDF spectra provide new insights into the polyhedral connectivity of nanoscale oxyanion-bearing HFO formed under a wide range of chemical conditions, improving predictions of EC performance in the field and allowing for knowledge-based improvements in the design of future EC systems. Our PDF data also show that the most disordered EC precipitate samples (formed at high oxyanion/Fe ratios) all share a similar "backbone" of 3-4 peaks beyond the first 4 Å, regardless of the oxyanion present during synthesis. Using 2LFH as a reference, we index all atomic pair correlations throughout the coherently scattering structure of our disordered samples.

  2. Moessbauer studies of the structural phase transitions in RbFeF4

    International Nuclear Information System (INIS)

    Baumeler, Hp.; Keller, H.; Kuendig, W.; Savic, I.M.; Wanklyn, B.M.

    1984-01-01

    RbFeF 4 exhibits two structural phase transitions (SPT), namely a first-order transition at 381 K and a second-order transition at 417 K. A detailed 57 Fe Moessbauer investigation of these SPT is presented. At pronounced discontinuities in the quadrupole splitting and the recoil-free fraction are observed, whereas at 417 K both quantities vary continuously with temperature. Both SPT are also seen in the area ratio of the single crystal quadrupole lines which reflects the tilting of the FeF 6 octahedra with respect to the c-axis. However, no noticeable indication of the SPT is found in the center shift. (Auth.)

  3. The Redshifted Hydrogen Balmer and Metastable He 1 Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec-scale Accretion Inflow?

    Science.gov (United States)

    Shi, Xi-Heng; Jiang, Peng; Wang, Hui-Yuan; Zhang, Shao-Hua; Ji, Tuo; Liu, Wen-Juan; Zhou, Hong-Yan

    2016-10-01

    The accretion of the interstellar medium onto central super-massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. However, few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example in which the rarely detected hydrogen Balmer and metastable He I absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg II, Fe II, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He I* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find that the absorbing medium is exposed to the radiation with ionization parameter U ≈ 10-1.8, and the density is n({{H}})≈ {10}9 {{cm}}-3. Thus the absorbing medium is located ˜4 pc away from the central engine. According to the similarity in the distance and physical conditions between the absorbing medium and the torus, we strongly propose the absorption line system as a candidate for the accretion inflow, which originates in the inner surface of the torus.

  4. Structure and magnetism in Co/X, Fe/Si, and Fe/(FeSi) multilayers

    Science.gov (United States)

    Franklin, Michael Ray

    Previous studies have shown that magnetic behavior in multilayers formed by repeating a bilayer unit comprised of a ferromagnetic layer and a non-magnetic spacer layer can be affected by small structural differences. For example, a macroscopic property such as giant magnetoresistance (GMR) is believed to depend significantly upon interfacial roughness. In this study, several complimentary structural probes were used to carefully characterize the structure of several sputtered multilayer systems-Co/Ag, Co/Cu, Co/Mo, Fe/Si, and Fe//[FeSi/]. X-ray diffraction (XRD) studies were used to examine the long-range structural order of the multilayers perpendicular to the plane of the layers. Transmission electron diffraction (TED) studies were used to probe the long-range order parallel to the layer plane. X-ray Absorption Fine Structure (XAFS) studies were used to determine the average local structural environment of the ferromagnetic atoms. For the Co/X systems, a simple correlation between crystal structure and saturation magnetization is discovered for the Co/Mo system. For the Fe/X systems, direct evidence of an Fe-silicide is found for the /[FeSi/] spacer layer but not for the Si spacer layer. Additionally, differences were observed in the magnetic behavior between the Fe in the nominally pure Fe layer and the Fe contained in the /[FeSi/] spacer layers.

  5. A new spectroscopic calibration to determine Teff and [Fe/H] of FGK dwarfs and giants

    Directory of Open Access Journals (Sweden)

    Teixeira G. D. C.

    2017-01-01

    Full Text Available We present a new spectroscopic calibration for a fast estimate of Teff and [Fe/H] for FGK dwarfs and GK giant stars. We used spectra from a joint sample of 708 stars, composed by 451 FGK dwarfs and 257 GK-giant stars with homogeneously determined spectroscopic stellar parameters. We have derived 322 EW line-ratios and 100 FeI lines that can be used to compute Teff and [Fe/H], respectively. We show that these calibrations are effective for FGK dwarfs and GK-giant stars in the following ranges: 4500 K < Teff < 6500 K, 2.5 < log g < 4.9 dex, and –0.8 < [Fe/H] < 0:5 dex. The new calibration has a standard deviation of 74 K for Teff and 0.07 dex for [Fe/H]. We use four independent samples of stars to test and verify the new calibration, a sample of giant stars, a sample composed of Gaia FGK benchmark stars, a sample of GK-giant stars from the DR1 of the Gaia-ESO survey, and a sample of FGK-dwarf stars. We present a new computer code, GeTCal, for automatically producing new calibration files based on any new sample of stars.

  6. Voyages of a successful text. The Dialogi of Gregory the Great in Medieval Sicily (XII-XIV Century

    Directory of Open Access Journals (Sweden)

    Rossana Barcellona

    2013-10-01

    Full Text Available This essay reconstructs two “Sicilian chapters” of great success from the Dialogi by Gregorius Magnus which were enjoyed in the medieval era. These are the legend of Placido (Placido is a Benedict's young disciple mentioned in the Dialogi, which has Sicily as a background, as recounted by Pietro, Deacon of Montecassino between the XI and the XII centuries, and the Sicilian vulgarization of the work, carried out by Giovanni Campolo in the first half of the XIV century. The literary voyage of Placido and the work of Campolo are two excellent examples of the circulation and the fruition of an exemplary and authoritative text. Each highlights the complex intricacy of religion, culture and politics in the various systems of power and in the various historical settings that the medieval age explored.

  7. X-ray emission lines from photoionized plasmas

    International Nuclear Information System (INIS)

    Liedahl, D.A.

    1992-11-01

    Plasma emission codes have become a standard tool for the analysis of spectroscopic data from cosmic X-ray sources. However, the assumption of collisional equilibrium, typically invoked in these codes, renders them inapplicable to many important astrophysical situations, particularly those involving X-ray photoionized nebulae, which are likely to exist in the circumsource environments of compact X-ray sources. X-ray line production in a photoionized plasma is primarily the result of radiative cascades following recombination. Through the development of atomic models of several highly-charged ions, this work extends the range of applicability of discrete spectral models to plasmas dominated by recombination. Assuming that ambient plasma conditions lie in the temperature range 10 5 --10 6 K and the density range 10 11 --10 16 cm -3 , X-ray line spectra are calculated over the wavelength range 5--45 angstrom using the HULLAC atomic physics package. Most of the work focuses on the Fe L-shell ions. Line ratios of the form (3s-2p)/(3d-2p) are shown to characterize the principal mode of line excitation, thereby providing a simple signature of photoionization. At electron densities exceeding 10 12 cm -3 , metastable state populations in the ground configurations approach their LTE value, resulting in the enrichment of the Fe L-shell recombination spectrum and a set of density-sensitive X-ray line ratios. Radiative recombination continua and emission lines produced selectively by Δn = 0 dielectronic recombination are shown to provide two classes of temperature diagnostics. Because of the extreme overionization, the recombination continua are expected to be narrow (ΔE/E much-lt 1), with ΔE = kT. Dielectronic recombination selectively drives radiative transitions that originate on states with vacancies in the 2s subshell, states that are inaccessible under pure RR population kinetics

  8. Musik-Stadt. Traditionen und Perspektiven urbaner Musikkulturen, XIV. mezinárodní kongres Gesellschaft für Musikforschung, Lipsko 28. září - 3. října 2008

    Czech Academy of Sciences Publication Activity Database

    Bajgarová, Jitka

    2008-01-01

    Roč. 45, 3-4 (2008), s. 401-403 ISSN 0018-7003. [ Musik -Stadt. Traditionen und Perspektiven urbaner Musik kulturen. XIV. internationaler Kongress der Gesellschaft für Musik forschung. Leipzig, 28.09.2008-03.10.2008] Institutional research plan: CEZ:AV0Z90580513 Keywords : music in the cities Subject RIV: AL - Art, Architecture, Cultural Heritage

  9. Strong 3D and 1D magnetism in hexagonal Fe-chalcogenides FeS and FeSe vs. weak magnetism in hexagonal FeTe.

    Science.gov (United States)

    Parker, David S

    2017-06-13

    We present a comparative theoretical study of the hexagonal forms of the Fe-chalcogenides FeS, FeSe and FeTe with their better known tetragonal forms. While the tetragonal forms exhibit only an incipient antiferromagnetism and experimentally show superconductivity when doped, the hexagonal forms of FeS and FeSe display a robust magnetism. We show that this strong magnetism arises from a van Hove singularity associated with the direct Fe-Fe c-axis chains in the generally more three-dimensional NiAs structure. We also find that hexagonal FeTe is much less magnetic than the other two hexagonal materials, so that unconventional magnetically-mediated superconductivity is possible, although a large T c value is unlikely.

  10. Formation of the Fe(II)-Fe(III) hydroxysulphate green rust during marine corrosion of steel

    International Nuclear Information System (INIS)

    Refait, Ph.; Memet, J.-B.; Bon, C.; Sabot, R.; Genin, J.-M.R.

    2003-01-01

    Rust layers formed on steel sheet piles immersed 1 m above the mud line for 25 years were analysed by Raman spectroscopy, scanning electron microscopy and elemental X-ray mappings (Fe, S, O). They consist of three main strata, the inner one mainly composed of magnetite, the intermediate one of iron(III) oxyhydroxides and the outer one of hydroxysulphate green rust GR(SO 4 2- ). Simulations of GRs formation in solutions having large [Cl - ]/[SO 4 2- ] ratios revealed that the hydroxysulphate GR(SO 4 2- ) was obtained instead of the hydroxychloride GR(Cl - ), as demonstrated by X-ray diffraction and transmission Moessbauer spectroscopy analyses. Measurements of the [S], [Fe] and [Cl] concentrations allowed us to establish that GR(SO 4 2- ) formed along with a drastic impoverishment of the solution in sulphate ions; the [Cl - ]/[SO 4 2- ] ratio increased from 12 to 240. The GR, acting like a 'sulphate pump', may favour the colonisation of the rust layers by sulphate reducing bacteria

  11. Study on feed forward neural network convex optimization for LiFePO4 battery parameters

    Science.gov (United States)

    Liu, Xuepeng; Zhao, Dongmei

    2017-08-01

    Based on the modern facility agriculture automatic walking equipment LiFePO4 Battery, the parameter identification of LiFePO4 Battery is analyzed. An improved method for the process model of li battery is proposed, and the on-line estimation algorithm is presented. The parameters of the battery are identified using feed forward network neural convex optimization algorithm.

  12. Strong 3D and 1D magnetism in hexagonal Fe-chalcogenides FeS and FeSe vs. weak magnetism in hexagonal FeTe

    Energy Technology Data Exchange (ETDEWEB)

    Parker, David S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-13

    We present a comparative theoretical study of the hexagonal forms of the Fe-chalcogenides FeS, FeSe and FeTe with their better known tetragonal forms. While the tetragonal forms exhibit only an incipient antiferromagnetism and experimentally show superconductivity when doped, the hexagonal forms of FeS and FeSe display a robust magnetism. We show that this strong magnetism arises from a van Hove singularity associated with the direct Fe-Fe c-axis chains in the generally more three-dimensional NiAs structure. We also find that hexagonal FeTe is much less magnetic than the other two hexagonal materials, so that unconventional magnetically-mediated superconductivity is possible, although a large Tc value is unlikely.

  13. Spin Hall magnetoresistance in Ta/CoFe2O4 nanostructures

    Science.gov (United States)

    Hui, Ya-Juan; Cheng, Wei-Ming; Zhang, Zhao-Bing; Ji, Hong-Kai; Cheng, Xiao-Min; You, Long; Miao, Xiang-Shui

    2016-07-01

    Spin Hall magnetoresistance (SMR) has been investigated in Ta/CoFe2O4 nanostructures grown on different substrates. Spin currents in CoFe2O4 films are electrically detected in adjacent Ta layers owing to inverse spin Hall effects. The sign of the magnetic-field-dependent resistivity signal shows different polarities along different axes, showing different spin-dependent electron transports. A cosinelike curve of the angular dependence signal with opposite polarity is observed in two orthogonal magnetization planes, whereas a basic line is observed in another plane, revealing the spin accumulation phenomenon. The roughness of the CoFe2O4 surface tuned by substrate strains is responsible for the extent of spin accumulations and the strength of the SMR signal in the nanostructures.

  14. Influence of FeEDDS, FeEDTA, FeDTPA, FeEDDHA, and FeSO4 on Marigold Growth and Nutrition, and Substrate and Runoff Chemistry

    Science.gov (United States)

    Objectives of the study were to determine effects of Fe source on plant growth, plant nutrition, substrate chemistry and runoff chemistry. Iron source (FS) treatments consisted of Fe-aminopolycarboxylic acid (APCA) complexones iron ethylenediaminetetraacetic acid (FeEDTA), iron [S, S']-ethylenediam...

  15. Preliminary optical design of the coronagraph for the ASPIICS formation flying mission

    Science.gov (United States)

    Vivès, S.; Lamy, P.; Saisse, M.; Boit, J.-L.; Koutchmy, S.

    2017-11-01

    Formation flyers open new perspectives and allow to conceive giant, externally-occulted coronagraphs using a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at approximately 100-150 m from the first one. ASPIICS (Association de Satellites Pour l'Imagerie et l'Interfromtrie de la Couronne Solaire) is a mission proposed to ESA in the framework of the PROBA-3 program of formation flying which is presently in phase A to exploit this technique for coronal observations. ASPIICS is composed of a single coronagraph which performs high spatial resolution imaging of the corona as well as 2-dimensional spectroscopy of several emission lines from the coronal base out to 3 R. The selected lines allow to address different coronal regions: the forbidden line of Fe XIV at 530.285 nm (coronal matter), Fe IX/X at 637.4 nm (coronal holes), HeI at 587.6 nm (cold matter). An additional broad spectral channel will image the white light corona so as to derive electron densities. The classical design of an externally occulted coronagraph is adapted to the detection of the very inner corona as close as 1.01 R and the addition of a Fabry-Perot interferometer using a so-called "etalon". This paper is dedicated to the description of the optical design and its critical components: the entrance optics and the FabryPerot interferometer.

  16. Politica e censura nella Francia di Louis XIV: Chavigny de La Bretonnière

    Directory of Open Access Journals (Sweden)

    Chiara Mainardi

    2012-06-01

    Full Text Available During the reign of Louis XIV French libertines were expressing their intellectual dissent by opposing absolutism and criticising historical and religious conflicts. While in France, before abrogating the Edict of Nantes, any opposition was suppressed, Chavigny de La Bretonnière supported a revolt against the Church and political power. The prominent role of clandestine literature in Old Regime France will be analysed in this paper by considering critical studies about libertinage. In particular, the political and antireligious discourse carried on by this author will be highlighted by taking into account his ‘lardons’, satirical articles against French government, his erotic novel La Religieuse en chemise and his ecclesiastic pamphlet Le Cochon mitré. In a true editorial campaign, Chavigny de La Bretonnière attaches French royal power, through the use of satire he depicts corrupted prelates as obscene creatures and he reforms libertine dialogue by enhancing broad political purposes. As a response to his critics and claims, Chavigny was kidnapped, tortured and imprisoned for life. His name disappeared from history.

  17. Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

    2017-09-15

    We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

  18. Moessbauer studies of the structural phase transitions in RbFeF/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Baumeler, Hp.; Keller, H.; Kuendig, W.; Savic, I.M.; Wanklyn, B.M.

    1984-03-20

    RbFeF/sub 4/ exhibits two structural phase transitions (SPT), namely a first-order transition at 381 K and a second-order transition at 417 K. A detailed /sup 57/Fe Moessbauer investigation of these SPT is presented. At pronounced discontinuities in the quadrupole splitting and the recoil-free fraction are observed, whereas at 417 K both quantities vary continuously with temperature. Both SPT are also seen in the area ratio of the single crystal quadrupole lines which reflects the tilting of the FeF/sub 6/ octahedra with respect to the c-axis. However, no noticeable indication of the SPT is found in the center shift.

  19. Paramagnetic resonance and susceptibility of ilmenite, FeTiO3 crystal

    Science.gov (United States)

    Mcdonald, P. F.; Parasiris, A.; Pandey, R. K.; Gries, B. L.; Kirk, W. P.

    1991-01-01

    Large high-purity single crystals of FeTiO3 with ilmenite structure have been grown from a stoichiometric melt of Fe2O3 and TiO2 under an inert atmosphere using the modified Czochralski technique. Susceptibility and X-band paramagnetic resonance studies have been performed. Susceptibility measurements indicate a Neel temperature of about 59 K. The paramagnetic resonance spectrum for magnetic field perpendicular to the crystal c axis consists of a portion of a single, very intense approximately Lorentzian absorption line with its peak at about 600 G and half width at half maximum almost 1200 G. The absorption extends to zero magnetic field. For magnetic field approximately parallel to the c axis, the paramagnetic absorption is much smaller and may be considered a superposition of two approximately Lorentzian line shapes. The magnetic resonance measurements indicate a weak temperature dependence and large angular anisotropy.

  20. Quantum-electrodynamic influences on the lifetime of metastable states

    International Nuclear Information System (INIS)

    Brenner, G.

    2007-01-01

    High-precision lifetime measurements of the metastable 1s 2 2s 2 2p 2 P 0 3/2 level in boronlike Ar XIV and the 3s 2 2p 2 P 0 3/2 level in aluminumlike Fe XIV were performed at the Heidelberg electron beam ion trap (HD-EBIT). The lifetimes were inferred by monitoring their optical decay curves resulting from the magnetic dipole (M1) transition 1s 2 2s 2 2p 2 P 0 3/2 - 2 P 0 1/2 and 3s 2 3p 2 P 0 3/2 - 2 P 0 1/2 to the ground state configuration with transition wavelengths of 441.256 nm and 530.29 nm, respectively. Possible systematic error sources were investigated by studying the dependence of the decay times of the curves on various trapping conditions with high statistical significance. A new trapping scheme for lifetime measurements at an EBIT has been applied and allowed to reach an unprecedented precision in the realm of lifetime determinations on highly charged ions. The results of 9.573(4)( +12 -5 ) ms (stat)(syst) for Ar XIV and 16.726(10)(+17) ms (stat)(syst) for Fe XIV with a relative accuracy of 0.14% and 0.13%, respectively, make these measurements for the first time sensitive to quantum electrodynamic effects like the electron anomalous magnetic moment (EAMM). The results, improving the accuracy of previous measurements by factors of 10 and 6, respectively, show a clear discrepancy of about 3σ and 4σ to the trend of existing theoretical models, which in almost all cases predict a shorter lifetime, when adjusted for the EAMM. The obvious disagreement between experimental results and the predictions points at the incompleteness of the theoretical models used. (orig.)

  1. Magnetic resonance and antiresonance in microwave transmission through nanocomposites with Fe{sub 3}Ni{sub 2} and FeNi{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Rinkevich, A.B. [M.N. Miheev Institute of Metal Physics Ural Branch of RAS, 18 S.Kovalevskaya St, Ekaterinburg 620990 (Russian Federation); Samoylovich, M.I. [OAO TsNITI “TEKHNOMASH”, 4 Ivana Franko St, Moscow 121108 (Russian Federation); Nemytova, O.V., E-mail: mif-83@mail.ru [M.N. Miheev Institute of Metal Physics Ural Branch of RAS, 18 S.Kovalevskaya St, Ekaterinburg 620990 (Russian Federation); Kuznetsov, E.A. [Nizhny Tagil branch of the Ekaterinburg state social-pedagogical university, 57 Krasnogvardeyskaya St, Nizhny Tagil 622031 (Russian Federation)

    2017-06-15

    Investigation of magnetic properties and microwave resonance phenomena in nanocomposites based on opal matrices containing the particles of intermetallide of Fe{sub 3}Ni{sub 2} and FeNi{sub 3} is carried out. The interactions which lead to the resonance changes of transmission and reflection coefficients are determined. Electromagnetic properties are measured in the millimeter frequency range. Special attention is paid to comparison between static and dynamic magnetic properties of nanocomposites. Frequency dependences of magnitude of lines of resonance features are obtained. Spectra of resonance and antiresonance are studied. The conditions when the magnetic antiresonance is observed are clarified. The X-ray phase analysis of the nanocomposites is performed and their structure is studied.

  2. Soft magnetic properties of hybrid ferromagnetic films with CoFe, NiFe, and NiFeCuMo layers

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong-Gu [Eastern-western Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Hwang, Do-Guwn [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Rhee, Jang-Roh [Dept. of Physics, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Lee, Sang-Suk, E-mail: sslee@sangji.ac.kr [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of)

    2011-09-30

    Two-layered ferromagnetic alloy films (NiFe and CoFe) with intermediate NiFeCuMo soft magnetic layers of different thicknesses were investigated to understand the relationship between coercivity and magnetization process by taking into account the strength of hard-axis saturation field. The thickness dependence of H{sub EC} (easy-axis coercivity), H{sub HS} (hard-axis saturation field), and {chi} (susceptibility) of the NiFeCuMo thin films in glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared using the ion beam deposition method was determined. The magnetic properties (H{sub EC}, H{sub HS}, and {chi}) of the ferromagnetic CoFe, NiFe three-layers with an intermediate NiFeCuMo super-soft magnetic layer were strongly dependent on the thickness of the NiFeCuMo layer.

  3. Synthesis of MIL-100(Fe at Low Temperature and Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Jing Shi

    2013-01-01

    Full Text Available MIL-100(Fe, a mesoporous metal-organic framework (MOF, has a large BET specific surface area and pore volume with the presence of a significant amount of accessible Lewis acid metal sites upon dehydration. The structural characteristics of MIL-100(Fe make it a good candidate for potential applications in gas storage, separation, and heterogeneous catalysis. Mainly, this MOF is obtained by the hydrothermal synthesis in a Teflon-lined autoclave at high temperature (>150°C under static conditions. However, this method has several disadvantages such as high temperature, high (autogenous pressure, long time, and comparable low MOF yield. Therefore, development of a facile method for synthesis of MIL-100(Fe is vitally important for fundamental understanding and practical application. Herein, MIL-100(Fe is synthesized by a facile low-temperature (90% still could be achieved, suggesting that this simple and energy saving method has the potential to be used practically.

  4. MIL-100-Fe derived N-doped Fe/Fe3C@C electrocatalysts for efficient oxygen reduction reaction

    Science.gov (United States)

    Guo, Dakai; Han, Sancan; Wang, Jiacheng; Zhu, Yufang

    2018-03-01

    N-doped porous Fe/Fe3C@C electrocatalysts were prepared by the pyrolysis of the hexamethylenetetramine (HMT)-incorporated MIL-100-Fe at different temperatures (700-1000 °C) under N2 atmosphere. Rotary evaporation of MIL-100-Fe and HMT solution could make more N-enriched HMT molecules enter into the pores of MIL-100-Fe, thus improving nitrogen contents of the final pyrolyzed samples. All pyrolyzed samples show porous textures with middle specific surface areas. The X-ray photoelectron spectroscopy (XPS) results demonstrate the successful introduction of N atoms into carbon framework. Sample Fe-N2-800 prepared by annealing the precursors with the HMT/MIL-100-Fe weight ratio of 2 at 800 °C exhibits the best electrocatalytic activity towards the oxygen reduction reaction (ORR) in terms of onset potential and current density because of high graphitic N and pyridinic N content. The enwrapped Fe/Fe3C nanoparticles and Fe-Nx active sites in these samples could also boost the ORR activity synergistically. Moreover, sample Fe-N2-800 demonstrates a dominant four electron reduction process, as well as excellent long-term operation stability and methanol crossover resistance. Thus, the N-doped Fe/Fe3C@C composites derived from the HMT-incorporated MIL-100-Fe are promising electrocatalysts to replace Pt/C for ORR in practical applications.

  5. The 54Fe(d,t)53Fe reaction and the neutron configuration in 54Fe

    International Nuclear Information System (INIS)

    England, J.B.A.; Ophel, T.R.; Johnston, A.; Zeller, A.F.

    1980-07-01

    The 54 Fe(d,t) 53 Fe reaction has been used to study the levels populated in 54 Fe in an attempt to establish the neutron configuration in 54 Fe. The states observed show clear evidence for a 2p-4h admixture in 54 Fe. In particular, the strength of the first 3/2 - level relative to the 7/2 - ground state transition is 3-4 times that in neighbouring N = 28 nuclei

  6. THE COMPLEX CIRCUMNUCLEAR ENVIRONMENT OF THE BROAD-LINE RADIO GALAXY 3C 390.3 REVEALED BY CHANDRA HETG

    Energy Technology Data Exchange (ETDEWEB)

    Tombesi, F.; Kallman, T.; Leutenegger, M. A. [X-ray Astrophysics Laboratory, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Reeves, J. N. [Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); Reynolds, C. S.; Mushotzky, R. F.; Behar, E. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Braito, V. [INAF—Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (Italy); Cappi, M., E-mail: francesco.tombesi@nasa.gov, E-mail: ftombesi@astro.umd.edu [Department of Physics, Technion 32000, Haifa 32000 (Israel)

    2016-10-20

    We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory . The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700–1000 eV associated with ionized Fe L transitions (Fe XVII–XX). An emission line at the energy of E ≃ 6.4 keV consistent with the Fe K α is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 ± 0.1 keV; (ii) a warm absorber with ionization parameter log ξ = 2.3 ± 0.5 erg s{sup −1} cm, column density log N {sub H} = 20.7 ± 0.1 cm{sup −2}, and outflow velocity v {sub out} < 150 km s{sup −1}; and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei.

  7. Statistical modeling of the reactions Fe(+) + N2O → FeO(+) + N2 and FeO(+) + CO → Fe(+) + CO2.

    Science.gov (United States)

    Ushakov, Vladimir G; Troe, Jürgen; Johnson, Ryan S; Guo, Hua; Ard, Shaun G; Melko, Joshua J; Shuman, Nicholas S; Viggiano, Albert A

    2015-08-14

    The rates of the reactions Fe(+) + N2O → FeO(+) + N2 and FeO(+) + CO → Fe(+) + CO2 are modeled by statistical rate theory accounting for energy- and angular momentum-specific rate constants for formation of the primary and secondary cationic adducts and their backward and forward reactions. The reactions are both suggested to proceed on sextet and quartet potential energy surfaces with efficient, but probably not complete, equilibration by spin-inversion of the populations of the sextet and quartet adducts. The influence of spin-inversion on the overall reaction rate is investigated. The differences of the two reaction rates mostly are due to different numbers of entrance states (atom + linear rotor or linear rotor + linear rotor, respectively). The reaction Fe(+) + N2O was studied either with (6)Fe(+) or with (4)Fe(+) reactants. Differences in the rate constants of (6)Fe(+) and (4)Fe(+) reacting with N2O are attributed to different contributions from electronically excited potential energy surfaces, such as they originate from the open-electronic shell reactants.

  8. Fe(III) mobilisation by carbonate in low temperature environments: Study of the solubility of ferrihydrite in carbonate media and the formation of Fe(III) carbonate complexes

    International Nuclear Information System (INIS)

    Grivé, Mireia; Duro, Lara; Bruno, Jordi

    2014-01-01

    Graphical abstract: - Highlights: • We have determined thermodynamic stabilities of Fe(III)-carbonate species. • We have determined the effect of those species on the solubility of ferrihydrite. • Results. • Highlight the importance of two Fe(III)-carbonate: FeOHCO 3 and Fe(CO 3 ) 3 3− . - Abstract: The linkage between the iron and the carbon cycles is of paramount importance to understand and quantify the effect of increased CO 2 concentrations in natural waters on the mobility of iron and associated trace elements. In this context, we have quantified the thermodynamic stability of mixed Fe(III) hydroxo-carbonate complexes and their effect on the solubility of Fe(III) oxihydroxides. We present the results of carefully performed solubility measurements of 2-line ferrihydrite in the slightly acidic to neutral–alkaline pH ranges (3.8–8.7) under constant pCO 2 varying between (0.982–98.154 kPa) at 25 °C. The outcome of the work indicates the predominance of two Fe(III) hydroxo carbonate complexes FeOHCO 3 and Fe(CO 3 ) 3 3− , with formation constants log * β° 1,1,1 = 10.76 ± 0.38 and log β° 1,0,3 = 24.24 ± 0.42, respectively. The solubility constant for the ferrihydrite used in this study was determined in acid conditions (pH: 1.8–3.2) in the absence of CO 2 and at T = (25 ± 1) °C, as log * K s,0 = 1.19 ± 0.41. The relative stability of the Fe(III)-carbonate complexes in alkaline pH conditions has implications for the solubility of Fe(III) in CO 2 -rich environments and the subsequent mobilisation of associated trace metals that will be explored in subsequent papers

  9. Spin structure of exchange biased heterostructures. Fe/MnF{sub 2} and Fe/FeF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, B

    2006-12-18

    In this work, the {sup 57}Fe probe layer technique is used in order to investigate the depth- and temperature-dependent Fe-layer spin structure of exchange biased Fe/MnF{sub 2} and Fe/FeF{sub 2} (pseudo-twinned) antiferromagnetic (AFM) systems by conversion electron Moessbauer spectroscopy (CEMS) and nuclear resonant scattering (NRS) of synchrotron radiation. Two kinds of samples with a 10 A {sup 57}Fe probe layer directly at or 35 A away from the interface, labeled as interface and center sample, respectively, were studied in this work. The results obtained by CEMS for Fe/MnF{sub 2} suggests that, at 80 K, i.e., above T{sub N}=67 K of MnF{sub 2}, the remanent state Fe-layer spin structure of the two studied samples are slightly different due to their different microstructure. In the temperature range from 300 K to 80 K, the Fe-layer spin structure does not change just by zero-field cooling the sample in remanence. For Fe/FeF{sub 2}, a continuous non-monotonic change of the remanent-state Fe spin structure was observed by cooling from 300 K to 18 K. NRS of synchrotron radiation was used to investigate the temperature- and depth-dependent Fe-layer spin structure during magnetization reversal in pseudo-twinned Fe/MnF{sub 2}. A depthdependent Fe spin structure in an applied magnetic field (applied along the bisector of the twin domains) was observed at 10 K, where the Fe spins closer to the interface are not aligned along the field direction. The depth-dependence disappears at 150 K. (orig.)

  10. Magnetic fields in proton solar flare of X17.2/4B class according to data of simultaneous measurements in a few spectral lines

    Science.gov (United States)

    Lozitsky, V.; Lozitska, N.

    2017-06-01

    Spectral-polarized magnetic field measurements in solar flare of 28 October 2003 of X17.2/4B class are compared in six FeI lines and in Hα line. Observations were carried out on Echelle spectrograph of horizontal solar telescope of Astronomical Observatory of Taras Shevchenko National University of Kyiv. Presented data relate to peak phase of flare and a place of photosphere outside sunspots where effective (average) magnetic field in FeI 6302.5 line was about 100 G and had S polarity. Measured splitting of emissive peaks in cores of strong FeI lines of 15th multiplet correspond to stronger fields, in range 550-700 G and S polarity too. Noticeablre splitting of emissive peaks (11-20 mÅ) were found also in Fe I 5434.527 line with effective Lande factor geff = -0.014. Value of this splitting and its sign indicate the existence of extremely strong fields of 25-50 kG of opposite (N) polarity which had negative Doppler velocities (lifting of plasma) on level of 1.7-2.2 km/sec. Magnetic field according to Hα line was 300 G and N polarity. Presented results indicate the essential inhomogeneity of magnetic field in flare volume which include the opposite polarities along the line of sight and wide range of effective magnetic fields.

  11. Production of Al-Si-Fe-Xalloys by Powder Mettalurgy

    Czech Academy of Sciences Publication Activity Database

    Školáková, A.; Novák, P.; Vojtěch, D.; Kubatík, Tomáš František

    2014-01-01

    Roč. 14, č. 3 (2014), s. 437-441 ISSN 1213-2489. [Mezinárodní konference „Mikroskopie a nedestruktivní zkoušení materiálů/3./. Litoměřice, 22.10.2014-24.10.2014] Institutional support: RVO:61389021 Keywords : Aluminium alloys * powder metallurgy * NiTi * mechanical alloying * reactive sintering Subject RIV: JG - Metallurgy http://journal.strojirenskatechnologie.cz/templates/obalky_casopis/XIV_2014-3.pdf

  12. How oxygen attacks [FeFe] hydrogenases from photosynthetic organisms

    Science.gov (United States)

    Stripp, Sven T.; Goldet, Gabrielle; Brandmayr, Caterina; Sanganas, Oliver; Vincent, Kylie A.; Haumann, Michael; Armstrong, Fraser A.; Happe, Thomas

    2009-01-01

    Green algae such as Chlamydomonas reinhardtii synthesize an [FeFe] hydrogenase that is highly active in hydrogen evolution. However, the extreme sensitivity of [FeFe] hydrogenases to oxygen presents a major challenge for exploiting these organisms to achieve sustainable photosynthetic hydrogen production. In this study, the mechanism of oxygen inactivation of the [FeFe] hydrogenase CrHydA1 from C. reinhardtii has been investigated. X-ray absorption spectroscopy shows that reaction with oxygen results in destruction of the [4Fe-4S] domain of the active site H-cluster while leaving the di-iron domain (2FeH) essentially intact. By protein film electrochemistry we were able to determine the order of events leading up to this destruction. Carbon monoxide, a competitive inhibitor of CrHydA1 which binds to an Fe atom of the 2FeH domain and is otherwise not known to attack FeS clusters in proteins, reacts nearly two orders of magnitude faster than oxygen and protects the enzyme against oxygen damage. These results therefore show that destruction of the [4Fe-4S] cluster is initiated by binding and reduction of oxygen at the di-iron domain—a key step that is blocked by carbon monoxide. The relatively slow attack by oxygen compared to carbon monoxide suggests that a very high level of discrimination can be achieved by subtle factors such as electronic effects (specific orbital overlap requirements) and steric constraints at the active site. PMID:19805068

  13. Fe-vacancy and superconductivity in FeSe-based superconductors

    Science.gov (United States)

    Wang, C. H.; Chen, T. K.; Chang, C. C.; Lee, Y. C.; Wang, M. J.; Huang, K. C.; Wu, P. M.; Wu, M. K.

    2018-06-01

    This review summarizes recent advancements in FeSe and related systems. The FeSe and related superconductors are currently receiving considerable attention for the high Tcs observed and for many similar features to the high Tc cuprate superconductors. These similarities suggest that understanding the FeSe based compounds could potentially help our understanding of the cuprates. We shall first review the common features observed in the FeSe-based system. It was found that with a careful control of material synthesizing processes, numerous rich phases have been observed in the FeSe-based system. Detailed studies show that the Fe-vacancy ordered phases found in the FeSe based compounds, which are non-superconducting Mott insulators, are the parent compounds of the superconductors. Superconductivity emerges from the parent phases by disordering the Fe vacancy order, often by a simple annealing treatment. Recent high temperature X-ray diffraction experiments show that the degree of structural distortion associated with the disorder of Fe-vacancy is closely related to volume fraction of the superconductivity observed. These results suggest the strong lattice to spin coupling are important for the occurrence of superconductivity in FeSe based superconductors.

  14. Effects of deviations from local thermodynamic equilibrium in the atmospheres of F supergiants. I. Overionization of Fe I atoms

    International Nuclear Information System (INIS)

    Boyarchuk, A.A.; Lyubimkov, L.S.; Sakhibullin, N.A.

    1985-01-01

    For a number of class F supergiants and dwarfs, non-LTE calculations have been made of the Fe I-Fe II ionization balance. It is shown that deviations from local thermodynamic equilibrium lead to a strong overionization of the Fe I atoms in the upper layers of the atmosphere. This confirms the conclusion obtained by Lyubimkov and Boyarchuk on the basis of an investigation of microturbulence in F supergiants. The reason for the overionization (compared with LTE) is the nonequality of the recombination and photoionization temperatures: To recombination processes there corresponds a local temperature T(/tau/), whereas the photoionization takes place under the influence of ultraviolet radiation from deeper and hotter layers of the atmosphere. The equivalent widths of some Fe I lines have been calculated. It is shown that neglect of the overionization in the analysis of sufficiently strong lines may lead to an underestimation of the iron abundance by an order of magnitude

  15. Exchange bias variations of the seed and top NiFe layers in NiFe/FeMn/NiFe trilayer as a function of seed layer thickness

    International Nuclear Information System (INIS)

    Sankaranarayanan, V.K.; Yoon, S.M.; Kim, C.G.; Kim, C.O.

    2005-01-01

    Development of exchange bias at the seed and top NiFe layers in the NiFe (t nm)/FeMn(10 nm)/NiFe(5 nm) trilayer structure is investigated as a function of seed layer thickness, in the range of 2-20 nm. The seed NiFe layer shows maximum exchange bias at 4 nm seed layer thickness. The bias shows inverse thickness dependence with increasing thickness. The top NiFe layer on the other hand shows only half the bias of the seed layer which is retained even after the sharp fall in seed layer bias. The much smaller bias for the top NiFe layer is related to the difference in crystalline texture and spin orientations at the top FeMn/NiFe interface, in comparison to the bottom NiFe/FeMn interface which grows on a saturated NiFe layer with (1 1 1) orientation

  16. Structural and magnetic properties of NdFeB and NdFeB/Fe films with Mo addition

    Energy Technology Data Exchange (ETDEWEB)

    Urse, M; Grigoras, M; Lupu, N; Chiriac, H, E-mail: urse@phys-iasi.ro [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)

    2011-07-06

    The influence of the Mo addition on the microstructure and magnetic properties of Nd-Fe-B and Nd-Fe-B/Fe films was studied. The coercivity is a key parameter in the control of technical performances of Nd-Fe-B films. A small amount of about 1 at.% Mo can enhance the coercivity of Nd-Fe-B film by controlling the growth of soft and hard magnetic grains. A coercivity of 22.1 kOe, a remanence ratio, M{sub r}/M{sub s}, of 0.83 and a maximum energy product of 8 MGOe were obtained for Ta/[NdFeBMo(1at.%)(540nm)/Ta films annealed at 650{sup 0}C for 20 minutes due to Mo precipitates formed at the Nd{sub 2}Fe{sub 14}B phase boundaries which prevent the nucleation and expansion of the magnetic domains. Simultaneous use of Mo as addition and the stratification of Nd-Fe-B-Mo films using Fe as spacer layer are important tools for the improvement of the hard magnetic properties of Nd-Fe-B films. The Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta multilayer film annealed at 620{sup 0}C exhibits an increase in the coercivity from 12.1 kOe to 22.8 kOe, in the remanence ratio from 0.77 to 0.80, and in the maximum energy product from 4.5 to 7.1 MGOe in comparison with Ta/Nd-Fe-B/Ta film. As compared to Ta/Nd-Fe-B/Ta film, the Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta film presents a decrease in the crystallization temperature of about 30{sup 0}C.

  17. Isotopic fractionation associated with [NiFe]- and [FeFe]-hydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hui; Gandhi, Hasand; Cornish, Adam J.; Moran, James J.; Kreuzer, Helen W.; Ostrom, Nathaniel; Hegg, Eric L.

    2016-01-30

    Hydrogenases catalyze the reversible formation of H2 from electrons and protons with high efficiency. Understanding the relationships between H2 production, H2 uptake, and H2-H2O exchange can provide insight into the metabolism of microbial communities in which H2 is an essential component in energy cycling. In this manuscript, we used stable H isotopes (1H and 2H) to probe the isotope effects associated with three [FeFe]-hydrogenases and three [NiFe]-hydrogenases. All six hydrogenases displayed fractionation factors for H2 formation that were significantly less than 1, producing H2 that was severely depleted in 2H relative to the substrate, water. Consistent with differences in their active site structure, the fractionation factors for each class appear to cluster, with the three [NiFe]-hydrogenases (α = 0.27-0.40) generally having smaller values than the three [FeFe]-hydrogenases (α = 0.41-0.55). We also obtained isotopic fractionation factors associated with H2 uptake and H2-H2O exchange under conditions similar to those utilized for H2 production, providing us with a more complete picture of the three reactions catalyzed by hydrogenases. The fractionation factors determined in our studies can be used as signatures for different hydrogenases to probe their activity under different growth conditions and to ascertain which hydrogenases are most responsible for H2 production and/or uptake in complex microbial communities.

  18. Comparison of explicit calculations for n = 3 to 8 dielectronic satellites of the FeXXV Kα resonance line with experimental data from the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Decaux, V.; Bitter, M.; Hsuan, H.; Hill, K.W.; von Goeler, S.; Park, H.; Bhalla, C.P.

    1991-12-01

    Dielectronic satellite spectra of the FeXXV Kα resonance line observed from the Tokamak Fusion Test Reactor (TFTR) plasmas have been compared with recent explicit calculations for the n = 3 to 8 dielectronic satellites as well as the earlier theoretical predictions, which were based on the 1/n 3 scaling law for n > 4 satellites. The analysis has been performed by least-squares fits of synthetic spectra to the experimental data. The synthetic spectra constructed from both theories are in good agreement with the observed data. However, the electron temperature values obtained from the fit of the present explicit calculations are in better agreement with independent measurements. 20 refs., 4 figs

  19. EPR spectroscopic investigations in 15BaO-25Li2O-(60-x) B2O3-xFe2O3 glass system

    Science.gov (United States)

    Bhogi, Ashok; Kumar, R. Vijaya; Kistaiah, P.

    2018-05-01

    Glasses with composition 15BaO-25Li2O-(60-x) B2O3 -xFe2O3 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1 mol %) were prepared by the conventional melt quenching technique. These glasses were characterized using X-ray diffraction (XRD). Electron paramagnetic resonance (EPR) investigations have been carried out as a function of iron ion concentration. The observed EPR spectra of Fe3+ ion exhibits resonance signals at g= 2.0, 4.3 and 8.0. The resonance signal at g= 4.3 is due to isolated Fe3+ ions in site with rhombic symmetry where as the g= 2.0 resonance signal is attributed to the Fe3+ ions coupled by exchange interaction in a distorted octahedral environment and the signal at g= 8.0 arises from axially distorted sites. The number of spins participating in resonance (N) and its paramagnetic susceptibilities (χ) have also been evaluated. The peak-to-peak line width ΔB for the resonance lines at g ≈ 4.3 and at g ≈ 2.0 is increasing as function of the iron ion content. The line intensity of the resonance centered at g ≈ 4.3 and at g ≈ 2.0 increases up to 0.8 mol% of Fe2O3 and for 1 mol% of Fe2O3 its value is found to decrease. The analysis of these results indicated that the conversion some of Fe3+ cations to Fe2+ ions beyond 0.8 mol%.

  20. Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Peterson, B. M.

    2005-01-01

    We study the low-contrast Fe II emission blends in the ultraviolet (1250--2200A) and optical (4000--6000A) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability ...... are correlated indicates that line fluorescence in a photoionized plasma, rather than collisional excitation, is responsible for the Fe II emission. The iron emission templates are available upon request....

  1. PHYSICAL CONDITIONS IN THE INNER NARROW-LINE REGION OF THE SEYFERT 2 GALAXY MARKARIAN 573

    International Nuclear Information System (INIS)

    Kraemer, S. B.; Trippe, M. L.; Crenshaw, D. M.; Fischer, T. C.; Melendez, M.; Schmitt, H. R.

    2009-01-01

    We have examined the physical conditions within a bright emission-line knot in the inner narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573 using optical spectra and photoionization models. The spectra were obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, through the 0.''2 x 52.''0 slit, at a position angle of -71. 0 2, with the G430L and G750M gratings. Comparing the spatial emission-line profiles, we found [Fe X] λ 6734 barely resolved, [O III] λ5007 centrally peaked, but broader than [Fe X], and [O II] λ3727 the most extended. Spectra of the central knot were extracted from a region 1.''1 in extent, corresponding to the full width at zero intensity in the cross-dispersion direction, of the knot. The spectra reveal that [Fe X] is broader in velocity width and blueshifted compared with lines from less ionized species. Our estimate of the bolometric luminosity indicates that the active galactic nucleus (AGN) is radiating at or above its Eddington luminosity, which is consistent with its identification as a hidden Narrow-Line Seyfert 1. We were able to successfully match the observed emission-line ratios with a three-component photoionization model. Two components, one to account for the [O III] emission and another in which the [Fe X] arises, are directly ionized by the AGN, while [O II] forms in a third component, which is ionized by a heavily absorbed continuum. Based on our assumed ionizing continuum and the model parameters, we determined that the two directly ionized components are ∼55 pc from the AGN. We have found similar radial distances for the central knots in the Seyfert 2 galaxies Mrk 3 and NGC 1068, but much smaller radial distances for the inner NLR in the Seyfert 1 galaxies NGC 4151 and NGC 5548. Although in general agreement with the unified model, these results suggest that the obscuring material in Seyfert galaxies extends out to at least tens of parsecs from the AGN.

  2. Influence of an Fe cap layer on the structural and magnetic properties of Fe49Pt51/Fe bi-layers

    International Nuclear Information System (INIS)

    Chao-Yang, Duan; Bin, Ma; Zong-Zhi, Zhang; Qing-Yuan, Jin; Fu-Lin, Wei

    2009-01-01

    The influences of an Fe cap layer on the structural and magnetic properties of FePt/Fe bi-layers are investigated. Compared with single FePt alloy films, a thin Fe layer can affect the crystalline orientation and improve the chemical ordering of L1 0 FePt films. Moreover, the coercivity increases when a thin Fe layer covers the FePt layer. Beyond a critical thickness, however, the Fe cover layer quickens the magnetization reversal of Fe 49 Pt 51 /Fe bi-layers by their exchange coupling

  3. Experimental design and methodology for a new Moessbauer scan experiment: absorption line tracking

    International Nuclear Information System (INIS)

    Veiga, A.; Pasquevich, G. A.; Zelis, P. Mendoza; Sanchez, F. H.; Fernandez van Raap, M. B.; Martinez, N.

    2009-01-01

    A new experimental setup and methodology that allows the automatic tracking of a Moessbauer absorption line as its energy position varies during the experiment is introduced. As a test the sixth spectral line of FeSn 2 was tracked while temperature was varied between room temperature and a value slightly above its Neel temperature.

  4. Structural and optical inhomogeneities of Fe doped GaN grown by hydride vapor phase epitaxy

    Science.gov (United States)

    Malguth, E.; Hoffmann, A.; Phillips, M. R.

    2008-12-01

    We present the results of cathodoluminescence experiments on a set of Fe doped GaN samples with Fe concentrations of 5×1017, 1×1018, 1×1019, and 2×1020 cm-3. These specimens were grown by hydride vapor phase epitaxy with different concentrations of Fe. The introduction of Fe is found to promote the formation of structurally inhomogeneous regions of increased donor concentration. We detect a tendency of these regions to form hexagonal pits at the surface. The locally increased carrier concentration leads to enhanced emission from the band edge and the internal T41(G)-A61(S) transition of Fe3+. In these areas, the luminescence forms a finely structured highly symmetric pattern, which is attributed to defect migration along strain-field lines. Fe doping is found to quench the yellow defect luminescence band and to enhance the blue luminescence band due to the lowering of the Fermi level and the formation of point defects, respectively.

  5. LiFePO4/C nanocomposites for lithium-ion batteries

    Science.gov (United States)

    Eftekhari, Ali

    2017-03-01

    LiFePO4, as the most famous member of the family of olivine-type lithium transition metal phosphates, is one of the promising candidates for the cathodes of lithium-ion batteries. However, its battery performance is limited by its low electrical conductivity and slow Li solid-state diffusion. Various methods have been attempted to improve the battery performance of lithium iron phosphate. Among them, compositing the LiFePO4 with carbon nanomaterials seems to be the most promising, as it is facile and efficient. Carbon nanomaterials usually serve as a conductive agent to improve the electrical conductivity while increasing the material porosity in which the solid-state diffusion distances are significantly shortened. Owing to the popularity of various carbonaceous nanomaterials, there is no straightforward line of research for comparing the LiFePO4/C nanocomposites. This review aims to provide a general perspective based on the research achievements reported in the literature. While surveying the research findings reported in the literature, controversial issues are also discussed. The possible contribution of pseudocapacitance as a result of functionalized carbon or LiFePO4 lattice defects is described, since from a practical perspective, a LiFePO4/C electrode can be considered as a supercapacitor at high C rates (with a specific capacitance as large as 200 F g-1). The Li diffusion in LiFePO4 has not been well understood yet; while the Li diffusion within the LiFePO4 lattice seems to be quite fast, the peculiar interfacial electrochemistry of LiFePO4 slows down the diffusion within the entire electrode by a few orders of magnitude.

  6. Mid-term periodicities and heliospheric modulation of coronal index ...

    Indian Academy of Sciences (India)

    PRITHVI RAJ SINGH

    2018-03-06

    Mar 6, 2018 ... long-term periodicity of ∼11 years, with different solar activities. The physical processes that occur inside the. Sun are reflected by a periodic character in terms of coronal index of coronal emission (Fe XIV 530.3 nm) during solar activity cycles. Recently, a link between the strength of photospheric magnetic ...

  7. XIV Jornadas de Redes de Investigación en Docencia Universitaria. Investigación, innovación y enseñanza universitaria: enfoques pluridisciplinares

    OpenAIRE

    Tortosa Ybáñez, María Teresa (coord.); Grau Company, Salvador (coord.); Álvarez Teruel, José Daniel (coord.)

    2016-01-01

    La investigación e innovación es un reto para la mejora de la calidad en la formación universitaria. Las Jornadas de Redes de la Universidad de Alicante tienen el compromiso con la comunidad universitaria de facilitar el intercambio de experiencias, promover el diálogo y la reflexión para identificar modos y buenas prácticas de enseñanza y generar conocimiento. A tal fin, las XIV Jornadas de Redes de Investigación en Docencia Universitaria se dirigen a docentes universitarios de todos los ámb...

  8. Microstructure and properties of multiphase sintered cermets Fe-Fe{sub 2}B; Mikrostruktura i wlasnosci spiekanych reakcyjnie cermetali Fe-Fe{sub 2}B

    Energy Technology Data Exchange (ETDEWEB)

    Nowacki, J. [Wydzial Inzynierii Materialowej, Politechnika Szczecinska, Szczecin (Poland); Klimek, L. [Instytut Inzynierii Materialowej i Technik Bezwiorowych, Politechnika Lodzka, Lodz (Poland)

    1998-12-31

    The process of multiphase sintering of iron in the vacuum has been analysed. As a result of the process iron-iron boride cermets have been produced. Fe-Fe{sub 2}B cermets were obtained as a result of sintering of the Fe and B pure elements in the vacuum. Attemps at sintering in the solid phase and with the participation of the liquid phase, the Fe-Fe{sub 2}B eutectic, have been made. Metallographic qualitative and quantitative studies, X-ray structural qualitative and qauantitative analysis allowed to determine the structure of Fe{sub 2}B cermets, as well as a description of the kinetics of quantitative changes in phase proportions in the course of sintering. It has been found that their structure varies widely depending on sintering parameters and the composition of the sinters. Measurements of the Fe-Fe{sub 2}B cermets hardness and measurements on wear during dry friction by the pin-on-disc method have shown distinct advantages of the cermets as a modern constructional materials. The hardness of Fe-Fe{sub 2}B cermets, depending on their chemical composition and sintering parameters, ranges widely from 150 to 1500 HV, and their resistance to wear is comparable to that of diffusively boronized steels. FeFe{sub 2}B cermets are a composite material in which iron boride, Fe{sub 2}B, with a hardness of about 1800 HV plays the role of the reinforcement,while iron-iron boride, Fe-Fe{sub 2}B, with a hardness of about 500 HV plays the role of matrix. The eutectic in the spaces between iron boride grains is composed of boron solid solution plates in iron with a hardness of arround 250 HV, and iron boride, Fe{sub 2}B, plates with a hardness of approximaly 1800 HV. The combination of such different materials, a hard reinforcement and a relatively plastic matrix produces favourable properties of the cermet thus produced high hardness (1500 HV) constant over whole cross section of the material, resistance of abrasive wear and acceptable ductility. The properties mentioned above

  9. Equilibrium Fe isotope fractionation between inorganic aqueous Fe(III) and the siderophore complex, Fe(III)-desferrioxamine B

    DEFF Research Database (Denmark)

    Dideriksen, Knud; Baker, Joel A.; Stipp, Susan Louise Svane

    2008-01-01

    be controlled by isotope fractionation between the free and complexed iron.We have determined the equilibrium Fe isotope fractionation induced by organic ligand activity in experiments with solutions having co-existing inorganic Fe(III) species and siderophore complexes, Fedesferrioxamine B (at pH 2). The two......-type fractionation during precipitation, this experiment yielded an isotope fractionation factor of a56Fesolution-solid=1.00027. Calculations based on these results indicate that isotopic re-equilibration is unlikely to significantly affect our determined equilibrium Fe isotope fractionation between inorganically...... and organically complexed Fe. To determine the equilibrium Fe isotope fractionation between inorganically and organically bound Fe(III), experiments with variable proportions of inorganic Fe were carried out at 25 °C. Irrespective of the proportion of inorganic Fe, equilibrium fractionation factors were within...

  10. Ferroelectric domains and phase evolution in (Fe:) KTa{sub 1−x}Nb{sub x}O{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hongyang; Cai, Kang; Fan, Ziran; Huang, Zhideng [Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Department of Materials Science and Engineering, Wuhan Institute of Technology, 693 Xiongchu Road, Wuhan 430073 (China); Ma, Zhibin, E-mail: mazb@wit.edu.cn [Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Department of Materials Science and Engineering, Wuhan Institute of Technology, 693 Xiongchu Road, Wuhan 430073 (China); Jia, Tingting; Kimura, Hideo [National Institute for Materials Science, Sengen 1-2-1, Tsukuba 305-0047 (Japan); Yang, Yuguo [New Materials Research Institute, Shandong Academy of Sciences, No. 19, Keyuan Road, Jinan 250014 (China); Matsumoto, Takao; Tohei, Tetsuya; Shibata, Naoya; Ikuhara, Yuichi [Institute of Engineering Innovation, School of Engineering, University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2017-08-15

    Highlights: • Three phase transitions were observed: the R–O, O–T, T–C evolutions. • KTN ferroelectric domain switching is because of the nano-polar-regions. • The domain evolution showed KTN has triangle shape, but Fe: KTN has straight line. - Abstract: The domain structures and phase evolution in mixed ferroelectric (Fe): KTa{sub 1−x}Nb{sub x}O{sub 3} (KTN) crystals were investigated. Temperature dependent Raman spectra show that Curie temperatures of KTN and Fe: KTN are far below room temperature, but the ferroelectric domain switching was still visualized by scanning probe microscopy at room temperature. These observed domains origin from the nano-regions near the grain boundaries. In addition, the intrinsic domains (triangle for KTN and straight line/stripe for Fe: KTN) could only be observed at low temperature by transmission electron microscopy. Three phase transitions in Fe: KTN crystals were found by Raman spectroscopy and dielectric testing: 175 K for Rhombohedral-to-Orthorhombic (R–O), 210 K for Orthorhombic-to-Tetragonal (O–T) and 250 K for Tetragonal-to-Cubic (T–C), which is consistent with the domain behavior.

  11. DISCOVERY OF Fe Kα X-RAY REVERBERATION AROUND THE BLACK HOLES IN MCG-5-23-16 AND NGC 7314

    International Nuclear Information System (INIS)

    Zoghbi, A.; Reynolds, C.; Cackett, E. M.; Miniutti, G.; Kara, E.; Fabian, A. C.

    2013-01-01

    Several X-ray observations have recently revealed the presence of reverberation time delays between spectral components in active galactic nuclei. Most of the observed lags are between the power-law Comptonization component, seen directly, and the soft excess produced by reflection in the vicinity of the black hole. NGC 4151 was the first object to show these lags in the iron K band. Here, we report the discovery of reverberation lags in the Fe K band in two other sources: MCG-5-23-16 and NGC 7314. In both objects, the 6-7 keV band, where the Feline peaks, lags the bands at lower and higher energies with a time delay of ∼1 ks. These lags are unlikely to be due to the narrow Feline. They are fully consistent with reverberation of the relativistically broadened iron Kα line. The measured lags, their time scale, and spectral modeling indicate that most of the radiation is emitted at ∼5 and 24 gravitational radii for MCG-5-23-16 and NGC 7314, respectively.

  12. Effectiveness of FeEDDHA, FeEDDHMA, and FeHBED in Preventing Iron-Deficiency Chlorosis in Soybean

    NARCIS (Netherlands)

    Bin, Levi M.; Weng, Liping; Bugter, Marcel H.J.

    2016-01-01

    The performance of FeHBED in preventing Fe deficiency chlorosis in soybean (Glycine max (L.) Merr.) in comparison to FeEDDHA and FeEDDHMA was studied, as well as the importance of the ortho-ortho and ortho-para/rest isomers in defining the performance. To this end, chlorophyll production (SPAD),

  13. Raman-spectroscopic (Fe/Fe+Mg, CO2) and Structural studies of Mg-Fe cordierites

    International Nuclear Information System (INIS)

    Haefeker, U.

    2013-01-01

    In the course of this dissertation synthetic hexagonal and orthorhombic Mg-Fe-cordierites have been investigated with Raman-spectroscopy and XRD methods. Cordierite´s Mg- and Fe-end-members as well as their Mg-Fe solid solutions with the chemical formula (Mg, Fe 2+ ) 2 Al 4 Si 5 O 18 *nH 2 O have been synthesized. Raman-data of synthetic hydrous Mg- and Fe-cordierites have been obtained in the wavenumber-region 100-1250 cm-1 and the experimental data were then compared with the results of quantum-mechanical calculations. 86 theoretical bands could be related to specific vibrational modes of the tetrahedral and octahedral sites of the cordierite structure. Maximum and mean deviation between experimentally-derived bands and calculated modes were ±7 cm -1 for Mg-cordierite and ±19 cm -1 for Fe-cordierite. Spectra comparison revealed a trend of peak downshifting as a consequence of Fe-incorporation. The calculations now allow more accurate interpretation of the Raman spectra with respect to structural changes of cordierite, resulting from Al-Si ordering and Mg-Fe exchange. Atomic motions in cordierite have been compared with those of the structurally similar mineral beryl. Investigations of 16 H 2 O-bearing synthetic well-ordered Mg-Fe-cordierites (XFe =0-1) with micro-Raman spectroscopy revealed a linear correlation between the Fe/Mg ratio and the position of certain Raman peaks. The peaks (wave-number Mg-/Fe-cordierite) at 122/111, 262/257, 430/418, 579/571, 974/967, and 1012/1007 cm -1 were selected for a detailed deconvolution analysis . The shifts of these peaks were then plotted vs. XFe and regression of the data lead to the formulation of a set of linear equations. In addition, the effect of different H 2 O contents and the degree of Al-Si ordering on the Fe/Mg determination were also investigated. Testing the calibration against data from six well-characterized natural cordierite samples yielded excellent agreement. Existing calibration diagrams for CO 2

  14. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-01-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaze, tourmaline and spodumene by measuring the first order Kα fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  15. Giant magnetoimpedance effect in sputtered single layered NiFe film and meander NiFe/Cu/NiFe film

    International Nuclear Information System (INIS)

    Chen, L.; Zhou, Y.; Lei, C.; Zhou, Z.M.; Ding, W.

    2010-01-01

    Giant magnetoimpedance (GMI) effect on NiFe thin film is very promising due to its application in developing the magnetic field sensors with highly sensitivity and low cost. In this paper, the single layered NiFe thin film and NiFe/Cu/NiFe thin film with a meander structure are prepared by the MEMS technology. The influences of sputtering parameters, film structure and conductor layer width on GMI effect in NiFe single layer and meander NiFe/Cu/NiFe film are investigated. Maximum of the GMI ratio in single layer and sandwich film is 5% and 64%, respectively. The results obtained are useful for developing the high-performance magnetic sensors based on NiFe thin film.

  16. Iron phosphate nanoparticles for food fortification: Biological effects in rats and human cell lines.

    Science.gov (United States)

    von Moos, Lea M; Schneider, Mirjam; Hilty, Florentine M; Hilbe, Monika; Arnold, Myrtha; Ziegler, Nathalie; Mato, Diogo Sales; Winkler, Hans; Tarik, Mohamed; Ludwig, Christian; Naegeli, Hanspeter; Langhans, Wolfgang; Zimmermann, Michael B; Sturla, Shana J; Trantakis, Ioannis A

    2017-05-01

    Nanotechnology offers new opportunities for providing health benefits in foods. Food fortification with iron phosphate nanoparticles (FePO 4 NPs) is a promising new approach to reducing iron deficiency because FePO 4 NPs combine high bioavailability with superior sensory performance in difficult to fortify foods. However, their safety remains largely untested. We fed rats for 90 days diets containing FePO 4 NPs at doses at which iron sulfate (FeSO 4 ), a commonly used food fortificant, has been shown to induce adverse effects. Feeding did not result in signs of toxicity, including oxidative stress, organ damage, excess iron accumulation in organs or histological changes. These safety data were corroborated by evidence that NPs were taken up by human gastrointestinal cell lines without reducing cell viability or inducing oxidative stress. Our findings suggest FePO 4 NPs appear to be as safe for ingestion as FeSO 4 .

  17. Note on: Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record, by Lieberman and Melott, arXiv preprint 0704.2896

    OpenAIRE

    Omerbashich, M.

    2007-01-01

    Lieberman and Melott built their recent arXiv preprint 0704.2896 on my published paper and (a preprint of) a subsequent comment by Liebermans associate Cornette. But had this group waited for the Cornette comment to actually appear in print together with the expected Reply, they would have learned that his comment exposes Cornettes confusion that likely was due to journal misprint of my figure. Thus 0704.2896 is baseless. Despite receiving the extended Reply with Errata, these authors still f...

  18. Study on tribological behaviors of Fe+ ion implanted in 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Zhang Aimin; Chen Jianmin; Shi Weidong; Liu Zhenmin

    2000-01-01

    2024 aluminum alloy was implanted with Fe + ions at a dose of 7x10 16 -3 x 10 17 Fe + /cm 2 . The depth profile of Fe element was investigated by Auger electron spectroscopy (AES). The composition of the surface layer was investigated by XRD with sample-tilting diffraction (STD) mode. The worn out surface was observed by scanning electron microscopy (SEM). Micro-hardness, friction and wear properties have been studied before and after Fe + implantation. An AES analysis shows Fe display Gaussian shape distributions. STD shows Al 5 Fe 2 formed during the implantation. Micro-hardness of surface layer was reduced after implantation, but it did not simply decrease with the increasing implantation doses. The friction and wear tests of implanted and unimplanted samples were carried out on a static-dynamic friction precise measuring apparatus. After implantation, the friction coefficient was reduced from 0.7 to 0.1; the wear resistance was improved remarkably, but decreased with increasing implantation dose. The wear mechanism of the unimplanted sample was adhesive wear, abrasive wear and plastic deformation. The wear reducing effect of Fe + ion induced on 2024 aluminum alloy is mainly attributed to tribooxidation of iron and transfixion of line defect. These two factors prevent the adhesive wear, abrasive wear and plastic deformation of 2024 aluminum alloy

  19. MCWASP XIV: International Conference on Modelling of Casting, Welding and Advanced Solidification Processes

    International Nuclear Information System (INIS)

    Yasuda, H

    2015-01-01

    The current volume represents contributed papers of the proceedings of the 14th international conference on ''Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP XIV)'', Yumebutai International Conference Center, Awaji island, Hyogo, Japan on 21 – 26 June, 2016. The first conference of the series 'Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP)' was started up in 1980, and this is the 14th conference. The participants are more than 100 scientists from industry and academia, coming from 19 countries. In the conference, we have 5 invited, 70 oral and 31 poster presentations on different aspects of the modeling. The conference deals with various casting processes (Ingot / shape casting, continuous casting, direct chill casting and welding), fundamental phenomena (nucleation and growth, dendritic growth, eutectic growth, micro-, meso- and macrostructure formation and defect formation), coupling problems (electromagnetic interactions, application of ultrasonic wave), development of experimental / computational methods and so on. This volume presents the cutting-edge research in the modeling of casting, welding and solidification processes. I would like to thank MAGMA Giessereitechnologie GmbH, Germany and SCSK Corporation, Japan for supporting the publication of contributed papers. Hideyuki Yasuda Conference Chairman Department of Materials Science and Engineering, Kyoto University Japan (preface)

  20. Molecular [(Fe3)–(Fe3)] and [(Fe4)–(Fe4)] coordination cluster pairs as single or composite arrays.

    Science.gov (United States)

    Sañudo, E Carolina; Uber, Jorge Salinas; Pons Balagué, Alba; Roubeau, Olivier; Aromí, Guillem

    2012-08-06

    The synthesis of molecular cluster pairs is a challenge for coordination chemists due to the potential applications of these species in molecular spintronics or quantum computing. The ligand H(4)L, 1,3-bis-(3-oxo-3-(2-hydroxyphenyl)-propionyl)-2-methoxybenzene, has been successfully used to obtain a series of such complexes using the basic Fe(III) trinuclear carboxylates as starting materials. Synthetic control has allowed the isolation of the two molecular cluster pairs that form the composite [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2)[Fe(3)O(PhCO(2))(5)(py)(H(2)L)](2) (1). The dimers of trinuclear units, [Fe(3)O(PhCO(2))(5)(H(2)O)(H(2)L)](2) (2) and [Fe(3)O(o-MePhCO(2))(5)(H(2)L)(py)](2) (3), and the dimers of tetranuclear units, [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2) (4) and [Fe(4)O(2)(o-MePhCO(2))(6)(H(2)L)(pz)](2) (5), are presented here. The magnetic properties of the reported aggregates show that they are pairs of semi-independent clusters weakly interacting magnetically as required for two-qubit quantum gates.

  1. Magnetic and thermal properties of amorphous TbFeCo alloy films

    Science.gov (United States)

    Wang, Ke; Dong, Shuo; Huang, Ya; Qiu, Yuzhen

    2017-07-01

    Amorphous TbFeCo material with perpendicular magnetic anisotropy is currently attracting more attention for potential applications in spintronic devices and logic memories. We systematically investigate magnetic, structural, thermal, optical and electrical properties of TbFeCo alloy films. It shows out-of-plane easy axis of the films turns into in-plane orientation after annealing. Significant increase in saturation magnetization in the temperature range between 400 and 450 °C is revealed by thermomagnetic measurements. The occurrence of crystallization and oxidation at high temperatures is confirmed by X-ray diffraction measurements. Pronounced changes in optical reflectance and sheet resistance are observed with temperature, in line with structural relaxation and change. The activation barriers for crystallization and oxidation are determined to be 1.01 eV and 0.83 eV, respectively, for FeCo-rich and Tb-rich samples. Better thermal stability against crystallization and oxidation is demonstrated in the FeCo-rich sample than the Tb-rich type. Our results provide some useful information for the alloy used in device fabrication.

  2. Homogeneity study of an Fe impurity in unalloyed Zn using PIXE

    International Nuclear Information System (INIS)

    Gamaz, Faziah; Chaves, Carlos; Waetjen, Uwe

    1999-01-01

    We have studied the distribution of an Fe impurity in unalloyed Zn material along line scans in spots of 1 mm diameter each using PIXE. In order to achieve the necessary precision (1%) in the determination of this low Fe content (about 100 mg/kg), a sufficient counting rate of Fe X-rays is needed without overloading the counting electronics with Zn X-rays at the same time. Therefore, the development of our PIXE analysis system had to take into account: (a) optimising the thickness of a Ni absorber foil in order to selectively reduce the counting rate of Zn without adding an unproportionally high Ni counting rate, (b) implementing a triggered ion beam deflection system capable of handling very high counting rates (up to 8 kcps), (c) developing the spectrum evaluation code to take account of the selective absorption by the Ni foil. The results of our PIXE measurements showed an inhomogeneity in Fe of up to 10%, considered too high to accept this zinc material as a new reference material

  3. A [4Fe-4S]-Fe(CO)(CN)-l-cysteine intermediate is the first organometallic precursor in [FeFe] hydrogenase H-cluster bioassembly

    Science.gov (United States)

    Rao, Guodong; Tao, Lizhi; Suess, Daniel L. M.; Britt, R. David

    2018-05-01

    Biosynthesis of the [FeFe] hydrogenase active site (the 'H-cluster') requires the interplay of multiple proteins and small molecules. Among them, the radical S-adenosylmethionine enzyme HydG, a tyrosine lyase, has been proposed to generate a complex that contains an Fe(CO)2(CN) moiety that is eventually incorporated into the H-cluster. Here we describe the characterization of an intermediate in the HydG reaction: a [4Fe-4S][(Cys)Fe(CO)(CN)] species, 'Complex A', in which a CO, a CN- and a cysteine (Cys) molecule bind to the unique 'dangler' Fe site of the auxiliary [5Fe-4S] cluster of HydG. The identification of this intermediate—the first organometallic precursor to the H-cluster—validates the previously hypothesized HydG reaction cycle and provides a basis for elucidating the biosynthetic origin of other moieties of the H-cluster.

  4. Study on adsorption of 99Tc on Fe, Fe2O3 and Fe3O4

    International Nuclear Information System (INIS)

    Liu Dejun; Fan Xianhua; Zhang Yingjie; Yao Jun; Zhou Duo; Wang Yong

    2004-01-01

    The absorption behavior of 99 Tc on Fe, Fe 2 O 3 and Fe 3 O 4 powders from aqueous 99 TcO 4 - solutions is studied by batch method in atmospheric conditions. After the adsorption reaches equilibrium, the valence state of 99 Tc in the aqueous solution is examined by extraction with tetraphenylarsonium chloride. The experimental results show that the adsorption ratio of 99 Tc on iron powders decreases with the increase of pH (in the range of 5-8) and of CO 3 2- concentration (in the range of 1 x 10 -8 -1 x 10 -2 mol/L). In opposite, the two factors have no significant influence on the absorption of 99 Tc on both Fe 2 O 3 and Fe 3 O 4 powders. The adsorption isotherms of 99 TcO 4 - on Fe, Fe 2 O 3 and Fe 3 O 4 powders can be well described by the Freundlich's equation. The major valence state of 99 Tc is deduced to be Tc(IV) when iron powders is used as the absorbent. In the case of Fe 2 O 3 or Fe 3 O 4 as an absorbent, the 99 Tc remains as the TcO 4 - form

  5. Atom exchange between aqueous Fe(II) and structural Fe in clay minerals.

    Science.gov (United States)

    Neumann, Anke; Wu, Lingling; Li, Weiqiang; Beard, Brian L; Johnson, Clark M; Rosso, Kevin M; Frierdich, Andrew J; Scherer, Michelle M

    2015-03-03

    Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories.

  6. Process and genes for expression and overexpression of active [FeFe] hydrogenases

    Science.gov (United States)

    Seibert, Michael; King, Paul W; Ghirardi, Maria Lucia; Posewitz, Matthew C; Smolinski, Sharon L

    2014-09-16

    A process for expression of active [FeFe]-hydrogenase in a host organism that does not contain either the structural gene(s) for [FeFe]-hydrogenases and/or homologues for the maturation genes HydE, HydF and HyG, comprising: cloning the structural hydrogenase gene(s) and/or the maturation genes HydE, HydF and HydG from an organisms that contains these genes into expression plasmids; transferring the plasmids into an organism that lacks a native [FeFe]-hydrogenase or that has a disrupted [FeFe]-hydrogenase and culturing it aerobically; and inducing anaerobiosis to provide [FeFe] hydrogenase biosynthesis and H?2#191 production.

  7. Photoelectron spectroscopy study of Fe-diluted Au-Fe alloys

    CERN Document Server

    Nahm, T U; Choi, B; Park, J S; Oh, S J; Cho, E J

    2003-01-01

    The electronic structure of Fe-diluted Au-Fe alloys has been studied by taking core-level and valence-band spectra using x-ray photoemission spectroscopy and synchrotron radiation. From the core-level spectroscopy, we found that the Fe 2p spectrum is composed of d sup 6 and d sup 7 multiplets from Fe impurity atoms. This behaviour is qualitatively discussed within the context of electron-electron interaction. In order to explore the electron-correlation effects in the valence band, we obtained Fe 3d partial spectral weights by taking advantage of the Cooper-minimum phenomenon of an Au 5d photoionization cross section. It was found that the spin-down states have an appreciable amount of spectral weights throughout the host Au 5d band, contrary to previous one-electron calculations predicting two-peak structure of the Fe 3d states. We suggest that this discrepancy results from the correlation effect of the Fe 3d electrons.

  8. Apache, Santa Fe energy units awarded two Myanmar blocks

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Myanmar's state oil company has awarded production sharing contracts (PSCs) on two blocks to units of Apache Corp. and Santa Fe Energy Resources Inc., both of Houston. That comes on the heels of a report by County NatWest Woodmac that notes Myanmar's oil production, currently meeting less than half the country's demand, is set to fall further this year. 150 line km of new seismic data could be acquired and one well drilled. During the initial 2 year exploration period on Block EP-3, Apache will conduct geological studies and conduct at least 200 line km of seismic data

  9. Colorimeter determination of Fe(II)/Fe(III) ratio in glass

    International Nuclear Information System (INIS)

    Baumann, E.W.; Coleman, C.J.; Karraker, D.G.; Scott, W.H.

    1987-01-01

    A colorimetric method has been developed to determine the Fe(II)/Fe(III) ratio in glass containing nuclear waste. Fe(II) is stabilized with pentavalent vanadium during dissolution in sulfuric and hydrofluoric acids. The chromogen is FerroZine (Hach Chemical Company), which forms a magenta complex with Fe(II). The two-step color development consists of determining the Fe(II) by adding FerroZine, followed by determining total Fe after the Fe(III) present is reduced with ascorbic acid. The method was validated by analyzing mixtures of ferrous/ferric solutions and nonferrous glass frit, and by comparison with Moessbauer spectroscopy. The effect of gamma radiation was established. The procedure is generally applicable to nonradioactive materials such as minerals and other glasses

  10. Spectroscopy and atomic physics of highly ionized Cr, Fe, and Ni for tokamak plasmas

    Science.gov (United States)

    Feldman, U.; Doschek, G. A.; Cheng, C.-C.; Bhatia, A. K.

    1980-01-01

    The paper considers the spectroscopy and atomic physics for some highly ionized Cr, Fe, and Ni ions produced in tokamak plasmas. Forbidden and intersystem wavelengths for Cr and Ni ions are extrapolated and interpolated using the known wavelengths for Fe lines identified in solar-flare plasmas. Tables of transition probabilities for the B I, C I, N I, O I, and F I isoelectronic sequences are presented, and collision strengths and transition probabilities for Cr, Fe, and Ni ions of the Be I sequence are given. Similarities of tokamak and solar spectra are discussed, and it is shown how the atomic data presented may be used to determine ion abundances and electron densities in low-density plasmas.

  11. Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

    Science.gov (United States)

    Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

    2002-01-16

    Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved.

  12. DISCOVERY OF Fe K{alpha} X-RAY REVERBERATION AROUND THE BLACK HOLES IN MCG-5-23-16 AND NGC 7314

    Energy Technology Data Exchange (ETDEWEB)

    Zoghbi, A.; Reynolds, C. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Cackett, E. M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St, Detroit, MI 48201 (United States); Miniutti, G. [Centro de Astrobiologia (CSIC-INTA), Dep. de Astrosica, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Kara, E.; Fabian, A. C., E-mail: azoghbi@astro.umd.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-04-20

    Several X-ray observations have recently revealed the presence of reverberation time delays between spectral components in active galactic nuclei. Most of the observed lags are between the power-law Comptonization component, seen directly, and the soft excess produced by reflection in the vicinity of the black hole. NGC 4151 was the first object to show these lags in the iron K band. Here, we report the discovery of reverberation lags in the Fe K band in two other sources: MCG-5-23-16 and NGC 7314. In both objects, the 6-7 keV band, where the Fe K{alpha} line peaks, lags the bands at lower and higher energies with a time delay of {approx}1 ks. These lags are unlikely to be due to the narrow Fe K{alpha} line. They are fully consistent with reverberation of the relativistically broadened iron K{alpha} line. The measured lags, their time scale, and spectral modeling indicate that most of the radiation is emitted at {approx}5 and 24 gravitational radii for MCG-5-23-16 and NGC 7314, respectively.

  13. Melting relations in the Fe-rich portion of the system FeFeS at 30 kb pressure

    Science.gov (United States)

    Brett, R.; Bell, P.M.

    1969-01-01

    The melting relations of FeFeS mixtures covering the composition range from Fe to Fe67S33 have been determined at 30 kb pressure. The phase relations are similar to those at low pressure. The eutectic has a composition of Fe72.9S27.1 and a temperature of 990??C. Solubility of S in Fe at elevated temperatures at 30 kb is of the same order of magnitude as at low pressure. Sulfur may have significantly lowered the melting point of iron in the upper mantle during the period of coalescence of metal prior to core formation in the primitive earth. ?? 1969.

  14. Superconducting fluctuation effect in CaFe0.88Co0.12AsF

    Science.gov (United States)

    Xiao, H.; Gao, B.; Ma, Y. H.; Li, X. J.; Mu, G.; Hu, T.

    2016-11-01

    Out-of-plane angular dependent torque measurements were performed on CaFe0.88Co0.12AsF single crystals. Superconducting fluctuations, featured by magnetic field enhanced and exponential temperature dependent diamagnetism, are observed above the superconducting transition temperature T c, which is similar to that of cuprate superconductors, but less pronounced. In addition, the ratio of T c versus superfluid density follows well the Uemura line of high-T c cuprates, which suggests the exotic nature of the superconductivity in CaFe0.88Co0.12AsF.

  15. Comparison of Ab initio low-energy models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe, and FeTe. Electron correlation and covalency

    International Nuclear Information System (INIS)

    Miyake, Takashi; Nakamura, Kazuma; Arita, Ryotaro; Imada, Masatoshi

    2010-01-01

    Effective low-energy Hamiltonians for several different families of iron-based superconductors are compared after deriving them from the downfolding scheme based on first-principles calculations. Systematic dependences of the derived model parameters on the families are elucidated, many of which are understood from the systematic variation of the covalency between Fe-3d and pnictogen-/chalcogen-p orbitals. First, LaFePO, LaFeAsO (1111), BaFe 2 As 2 (122), LiFeAs (111), FeSe, and FeTe (11) have overall similar band structures near the Fermi level, where the total widths of 10-fold Fe-3d bands are mostly around 4.5 eV. However, the derived effective models of the 10-fold Fe-3d bands (d model) for FeSe and FeTe have substantially larger effective onsite Coulomb interactions U - 4.2 and 3.4 eV, respectively, after the screening by electrons on other bands and after averaging over orbitals, as compared to ∼2.5 eV for LaFeAsO. The difference is similar in the effective models containing p orbitals of As, Se or Te (dp or dpp model), where U ranges from ∼4 eV for the 1111 family to ∼7 eV for the 11 family. The exchange interaction J has a similar tendency. The family dependence of models indicates a wide variation ranging from weak correlation regime (LaFePO) to substantially strong correlation regime (FeSe). The origin of the larger effective interaction in the 11 family is ascribed to smaller spread of the Wannier orbitals generating larger bare interaction, and to fewer screening channels by the other bands. This variation is primarily derived from the distance h between the pnictogen/chalcogen position and the Fe layer: The longer h for the 11 family generates more ionic character of the bonding between iron and anion atoms, while the shorter h for the 1111 family leads to more covalent-bonding character, the larger spread of the Wannier orbitals, and more efficient screening by the anion p orbitals. The screened interaction of the d model is strongly orbital

  16. X-ray fluorescence analysis of Fe, Mn, Cr and V in natural silicate crystals

    International Nuclear Information System (INIS)

    Dias, O.L.; Albuquerque, A.R.P.L.; Isotani, S.

    1983-04-01

    Concentrations of Fe, Mn, Cr and V were determined in samples of beryl, topaz, tourmaline and spodumene by measuring the first order K sub(α) fluorescence lines. The intensity of these lines were calibrated by using beryl as the standard matrix. The matrices were prepared in the form of pressed pellets with 4:1 mixture of beryl and boric acid, where transition metal oxides were added. (Author) [pt

  17. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Luping [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhan, Qingfeng, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Li, Run-Wei, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Tan, Xiaohua [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2016-03-15

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  18. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    International Nuclear Information System (INIS)

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Li, Run-Wei; Tan, Xiaohua

    2016-01-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  19. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Science.gov (United States)

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Tan, Xiaohua; Li, Run-Wei

    2016-03-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  20. Effect of Fe3O4 Nanoparticles on Skin Tumor Cells and Dermal Fibroblasts

    Directory of Open Access Journals (Sweden)

    Lirija Alili

    2015-01-01

    Full Text Available Iron oxide (Fe3O4 nanoparticles have been used in many biomedical approaches. The toxicity of Fe3O4 nanoparticles on mammalian cells was published recently. Though, little is known about the viability of human cells after treatment with Fe3O4 nanoparticles. Herein, we examined the toxicity, production of reactive oxygen species, and invasive capacity after treatment of human dermal fibroblasts (HDF and cells of the squamous tumor cell line (SCL-1 with Fe3O4 nanoparticles. These nanoparticles had an average size of 65 nm. Fe3O4 nanoparticles induced oxidative stress via generation of reactive oxygen species (ROS and subsequent initiation of lipid peroxidation. Furthermore, the question was addressed of whether Fe3O4 nanoparticles affect myofibroblast formation, known to be involved in tumor invasion. Herein, Fe3O4 nanoparticles prevent the expression alpha-smooth muscle actin and therefore decrease the number of myofibroblastic cells. Moreover, our data show in vitro that concentrations of Fe3O4 nanoparticles, which are nontoxic for normal cells, partially reveal a ROS-triggered cytotoxic but also a pro-invasive effect on the fraction of squamous cancer cells surviving the treatment with Fe3O4 nanoparticles. The data herein show that the Fe3O4 nanoparticles appear not to be adequate for use in therapeutic approaches against cancer cells, in contrast to recently published data with cerium oxide nanoparticles.

  1. First 2017-total-eclipse results from the Williams College team

    Science.gov (United States)

    Pasachoff, J.; Dantowitz, R.; Rusin, V.; Seiradakis, J. H.; Voulgaris, A.; Seaton, D. B.; Davis, A. B.; Lu, M.; Sliski, D.; Ladd, E. F.; Economou, T.; Peñaloza-Murillo, M. A.; Nagle-McNaughton, T.

    2017-12-01

    We report on a wide range of observations we carried out during the total solar eclipse of August 21, 2017. Our main site was on the campus of Willamette University, Salem, Oregon, at which we had a variety of telescopes, spectrographs, cameras, a grism, and terrestrial-atmospheric measuring devices. Our goals included differentiating between models of coronal heating through measuring power-spectra of coronal loops in the [Fe XIV] and [Fe X] emission lines at multi-Hertz cadence with a frame-transfer CCD and otherwise; following coronal structure over the solar-activity cycle; comparing the results of a full-MHD prediction with actual coronal streamers; studying the dynamics of coronal plumes given the minimum phase of the solar-activity cycle; measuring the variation of the corona over the solar-activity cycle from our continuing measurements of the green-line/red-line intensity ratio; studying a variety of additional coronal emisson lines; high-resolution coronal imaging compared with overlapping images from space coronagraphs aboard SoHO and STEREO; comparing with AIA/SDO, HMO/SDO, SUVI/GOES-16, and SWAP/PROBA2 space images; and more. Our research has been supported in large part by grants from the Committee for Research and Exploration of the National Geographic Society and from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation, with additional support from Sigma Xi. Additional support for undergraduate participation came from the NSF, the NASA Massachusetts Space Grant Consortium, and the Clare Booth Luce Foundation, with travel support from the Freeman Foote Fund, the Rob Spring Fund, the Brandi Fund, and other sources at Williams College.

  2. Near surface silicide formation after off-normal Fe-implantation of Si(001) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de; Pietsch, U. [Solid State Physics, University of Siegen, D-57068 Siegen (Germany); Lützenkirchen-Hecht, D. [Fachbereich C - Physik, Bergische Universität Wuppertal, D-42097 Wuppertal (Germany); Hübner, R.; Grenzer, J.; Facsko, S. [Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany)

    2014-07-14

    We report on formation of non-crystalline Fe-silicides of various stoichiometries below the amorphized surface of crystalline Si(001) after irradiation with 5 keV Fe{sup +} ions under off-normal incidence. We examined samples prepared with ion fluences of 0.1 × 10{sup 17} and 5 × 10{sup 17} ions cm{sup −2} exhibiting a flat and patterned surface morphology, respectively. Whereas the iron silicides are found across the whole surface of the flat sample, they are concentrated at the top of ridges at the rippled surface. A depth resolved analysis of the chemical states of Si and Fe atoms in the near surface region was performed by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy (XAS) using synchrotron radiation. The chemical shift and the line shape of the Si 2p core levels and valence bands were measured and associated with the formation of silicide bonds of different stoichiometric composition changing from an Fe-rich silicides (Fe{sub 3}Si) close to the surface into a Si-rich silicide (FeSi{sub 2}) towards the inner interface to the Si(001) substrate. This finding is supported by XAS analysis at the Fe K-edge which shows changes of the chemical environment and the near order atomic coordination of the Fe atoms in the region close to surface. Because a similar Fe depth profile has been found for samples co-sputtered with Fe during Kr{sup +} ion irradiation, our results suggest the importance of chemically bonded Fe in the surface region for the process of ripple formation.

  3. Communication dated 18 December 2000 received from the Permanent Mission of the United Kingdom to the International Atomic Energy Agency regarding amendments to article VI and XIV of the statute of the Agency

    International Nuclear Information System (INIS)

    2000-01-01

    The letter communicates the United Kingdom acceptance of the amendments to Articles VI and XIV of the IAEA Statute, agreed by the General Conference on 1 October 1999. The instrument of Notification of Acceptance, signed by the Foreign Secretary, Robin Cook, on 20 November 2000, has been deposited with the U.S. Government as the depository Government

  4. The ecological behaviour of 55Fe in plants and in the flesh of cattle and game

    International Nuclear Information System (INIS)

    Barwinek, F.; Kreuzer, W.; Sansoni, B.; Kernforschungsanlage Juelich G.m.b.H.

    1980-01-01

    98 samples of shrub lichens taken between 1965 and 1970, including 69 from the Federal Republic of Germany and 15 from Finland, mainly of the genus Cladonia, particularly the species Cladonia rangiferina and Cladonia silvatica, 5 samples of moss, 2 of heather and 4 of hay, and also meat samples taken from 12 Bavarian cattle slaughtered in the spring of 1970, 7 stags killed in the Eastern Carpathians in the autumn of 1969 and one chamois shot in the Lower Tauern mountains in the autumn of 1970, were all analysed for their contents of 55 Fe and stable Fe. The lichens contained between 0.7 - in 1970 - and a maximum of 139.0 nCi 55 Fe/kg dry matter - in 1965, or between 0.09 and 6.9 nCi/g ash. Their stable Fe contents varied between 0.234 and 1.990 mg/g dry matter or between 16.3 and 59.7 mg/Fe/g ash. Specific 55 Fe activities of between 231 pCi 55 Fe/mg Fe (1964) and 1.6 pCi 55 Fe/mg Fe (1970) can be calculated from these values. There were no obvious differences between the 55 Fe contamination of lichens of different species. This was also true of their contents of stable Fe. Cladonia furcata had the highest contents of 55 Fe and stable Fe, both relatively and absolutely. From 1965 onwards the 55 Fe-activities in the lichens examined declined in line with the drop in 55 Fe in the fall-out. (orig./AJ.) [de

  5. Preprints na comunicação científica da Física de Altas Energias: análise das submissões no repositório arXiv (2010-2015

    Directory of Open Access Journals (Sweden)

    Gonzalo Rubén Alvarez

    Full Text Available RESUMO A circulação de preprints na Física de Altas Energias (FAE remonta a mais de meio século, tendo como objetivos principais acelerar o processo de comunicação científica entre os pares e estimular o acesso livre à literatura especializada da área. O artigo analisa o conjunto de preprints submetidos às diferentes categorias FAE do repositório temático especializado arXiv no período 2010-2015 que foram posteriormente publicados em revistas peer review. Os indicadores bibliométricos demonstram a potencialidade dos preprints como canal precursor de difusão de resultados científicos visto que 70% das submissões foram em seguida absorvidas pelas principais revistas da FAE. Conclui que o êxito alcançado pelas iniciativas Open Access arXiv e INSPIRE-HEP favoreceu o intercâmbio de informações e conhecimentos entre os pesquisadores. O modelo proposto pela FAE pode incentivar cientistas de áreas com características similares a instalarem repositórios e bancos de dados de preprints para suas disciplinas com o intuito de fortalecer a comunicação das descobertas científicas.

  6. Clarifying roughness and atomic diffusion contributions to the interface broadening in exchange-biased NiFe/FeMn/NiFe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, V.P., E-mail: valberpn@yahoo.com.br [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Merino, I.L.C.; Passamani, E.C. [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Alayo, W. [Departamento de Física, Universidade de Pelotas, 96010-610 Pelotas (Brazil); Tafur, M. [Instituto de Ciências Exatas, Universidade Federal de Itajubá, 37500-903 Itajubá (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, 74001-970 Goiânia (Brazil); Magalhães-Paniago, R. [Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Alvarenga, A.D. [Instituto Nacional de Metrologia, 25250-020 Xerém (Brazil); Saitovitch, E.B. [Coordenação de Física Experimental e Baixas Energias, Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro (Brazil)

    2013-09-02

    NiFe(30 nm)/FeMn(13 nm)/NiFe(10 nm) heterostructures prepared by magnetron sputtering at different argon working pressures (0.27, 0.67 and 1.33 Pa) were systematically investigated by using specular and off-specular diffuse X-ray scattering experiments, combined with ferromagnetic resonance technique, in order to distinguish the contribution from roughness and atomic diffusion to the total structural disorder at NiFe/FeMn interfaces. It was shown that an increase in the working gas pressure from 0.27 to 1.33 Pa causes an enhancement of the atomic diffusion at the NiFe/FeMn interfaces, an effect more pronounced at the top FeMn/NiFe interface. In particular, this atomic diffusion provokes a formation of non-uniform magnetic dead-layers at the NiFe/FeMn interfaces (NiFeMn regions with paramagnetic or weak antiferromagnetic properties); that are responsible for the substantial reduction of the exchange bias field in the NiFe/FeMn system. Thus, this work generically helps to understand the discrepancies found in the literature regarding the influence of the interface broadening on the exchange bias properties (e.g., exchange bias field) of the NiFe/FeMn system. - Highlights: • Roughness and atomic diffusion contributions to the interface broadening • Clarification of the exchange bias field dependence on the interface disorder • Ferromagnetic, paramagnetic and antiferromagnetic phases at the magnetic interface • Magnetic dead layers formed by increasing the argon work pressure • Atomic diffusion in heterostructures prepared at higher argon pressure.

  7. An X- and Q-band Fe3+ EPR study of nanoparticles of magnetic semiconductor Zn1−xFexO

    International Nuclear Information System (INIS)

    Misra, Sushil K.; Andronenko, S.I.; Thurber, A.; Punnoose, A.; Nalepa, A.

    2014-01-01

    EPR studies on two types of nanoparticles of Fe 3+ doped, 0.1–10%, ZnO, NL and QJ, prepared using similar chemical hydrolysis methods, in diethylene glycol, and in denatured ethanol solutions, respectively, were carried out at X-band (∼9.5 GHz) at 77 K and at Q-band (∼34.0 GHz) at 10, 80, and 295 K. To interpret the experimental results, EPR spectra were simulated by exact diagonalization of the spin-Hamiltonian matrix to identify the Fe ions at different magnetically active sites in these samples. The simulation for NL samples revealed that they contained (i) Fe 3+ ions, which substituted for Zn ions, the zero-field splitting (ZFS) parameter which has a large distribution over the sample due to oxygen vacancies in the second coordination sphere; (ii) EPR signal from surface oxygen defects; and (iii) ferromagnetically (FM) coupled Fe ions with concentration of Fe more than 1%. The EPR spectra for QJ samples are very different from those for NL samples, exhibiting only rather intense FM EPR lines. The FM and EPR spectra in NL and/or QJ samples are found to vary strongly with differences in the surface morphology of nanoparticles. - Highlights: • X and Q band EPR studies on NL and QJ nanoparticles of Fe 3+ doped ZnO at 10, 80, and 295 K. • Fe ions are present at different magnetically active sites in these samples. • NL samples consist of paramagnetic Fe 3+ ions, and ferromagnetically coupled Fe ions. • QJ samples exhibit only intense ferromagnetic lines, different from QJ. • Spectra vary strongly with the surface morphology of nanoparticles

  8. Intensity of the Fe XV emission line corona, the level of geomagnetic activity and the velocity of the solar wind

    International Nuclear Information System (INIS)

    Bell, B.; Noci, G.

    1976-01-01

    The average solar wind velocity and the level of geomagnetic activity (Kp) following central meridian passage of coronal weak and bright features identified from Oso 7 isophotograms of Fe XV (284 A) are determined by the method of superposed epochs. Results are consistent with the concept that bright regions possess magnetic field of closed configurations, thereby reducing particle escape, while coronal holes possess open magnetic field lines favorable to particle escape or enhanced outflow of the solar wind. Coronal holes are identified with Bartels' M regions not only statistically but by linking specific long-lived holes with individual sequences of geomagnetic storms. In the study of bright region a subdivision by brightness temperature (T/sub b/) of associated 9.1-cm radiation was found to be significant, with the region s of higher T/sub b/ having a stronger inhibiting power on the outflow of the solar wind when they were located in the solar hemisphere on the same side of the solar equator as the earth. Regions of highest T/sub b/ most strongly depress the outflow of solar wind but are also the most likely to produce flare-associated great storms

  9. Synthesis of Fe Nanoparticles Functionalized with Oleic Acid Synthesized by Inert Gas Condensation

    Directory of Open Access Journals (Sweden)

    L. G. Silva

    2014-01-01

    Full Text Available In this work, we study the synthesis of monodispersed Fe nanoparticles (Fe-NPs in situ functionalized with oleic acid. The nanoparticles were self-assembled by inert gas condensation (IGC technique by using magnetron-sputtering process. Structural characterization of Fe-NPs was performed by transmission electron microscopy (TEM. Particle size control was carried out through the following parameters: (i condensation zone length, (ii magnetron power, and (iii gas flow (Ar and He. Typically the nanoparticles generated by IGC showed diameters which ranged from ~0.7 to 20 nm. Mass spectroscopy of Fe-NPs in the deposition system allowed the study of in situ nanoparticle formation, through a quadrupole mass filter (QMF that one can use together with a mass filter. When the deposition system works without quadrupole mass filter, the particle diameter distribution is around +/−20%. When the quadrupole is in line, then the distribution can be reduced to around +/−2%.

  10. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India)

    2017-06-20

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V -band light curves from the Catalina Real Time Transient Survey that span 5–9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe ii strength but correlated with the width of the H β line. The well-known anti-correlation of variability–luminosity and the variability–Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  11. Point defects in B.C.C. Fe-Al, Fe-Co, and Fe-Co-V ordered alloys

    International Nuclear Information System (INIS)

    Riviere, J.P.; Dinhut, J.F.

    1982-01-01

    Radiation damage produced at 20 K by 2.5 MeV electrons is studied in three B 2 type Fe-40 at % Al, Fe-Co, Fe-Co-V ordered alloys. The resistivity damage in Fe-40 at % Al ordered single crystals is found less effective in the directions. The results suggest that replacement collision chains are difficult to propagate along the direction. Frenkel pair creation superimposed with disordering can account for the resistivity damage in the initially ordered Fe-Co alloy. Informations concerning replacement collision sequences in direction are derived. During the recovery of all the alloys, three main stages are observed and an ordering enhancement occurs. (author)

  12. Mapping and characterization of the new adult plant leaf rust resistance gene Lr77 derived from Santa Fe winter wheat.

    Science.gov (United States)

    Kolmer, James A; Su, Zhenqi; Bernardo, Amy; Bai, Guihua; Chao, Shiaoman

    2018-04-25

    A new gene for adult plant leaf rust resistance in wheat was mapped to chromosome 3BL. This gene was designated as Lr77. 'Santa Fe' is a hard red winter cultivar that has had long-lasting resistance to the leaf rust fungus, Puccinia triticina. The objective of this study was to determine the chromosome location of the adult plant leaf rust resistance in Santa Fe wheat. A partial backcross line of 'Thatcher' (Tc) wheat with adult plant leaf rust resistance derived from Santa Fe was crossed with Thatcher to develop a Thatcher//Tc*2/Santa Fe F 6 recombinant inbred line (RIL) population. The RIL population and parental lines were evaluated for segregation of leaf rust resistance in three field plot tests and in an adult plant greenhouse test. A genetic map of the RIL population was constructed using 90,000 single-nucleotide polymorphism (SNP) markers with the Illumina Infinium iSelect 90K wheat bead array. A significant quantitative trait locus for reduction of leaf rust severity in all four tests was found on chromosome 3BL that segregated as a single adult plant resistance gene. The RILs with the allele from the resistant parent for SNP marker IWB10344 had lower leaf rust severity and a moderately resistant to moderately susceptible response compared to the susceptible RILs and Thatcher. The gene derived from Santa Fe on chromosome 3BL was designated as Lr77. Kompetitive allele-specific polymerase chain reaction assay markers linked to Lr77 on 3BL should be useful for selection of wheat germplasm with this gene.

  13. Thermodynamics of the Mo-Fe-C and W-Fe-C systems

    International Nuclear Information System (INIS)

    Kleykamp, H.

    1978-01-01

    A study on the reaction behaviour of the components of the Mo 2 C-Fe and WC-Fe systems is presented. Both systems are stable if the mono-phase carbides are in equilibrium with the Fe-C solid solution within fixed carbon concentrations, the limits of which are calculated in this paper. Gibbs energies of formation at 1273 K of the intermetallic phases, of the binary and of the ternary carbides in the Mo-Fe-C and W-Fe-C systems were determined. The Fe corner in the phase diagrams of both systems and the calculated C boundaries in the two-phase field γ-Fe(Mo,C)-Mo 2 C and the γ-Fe(W,C)-WC, respectively, based on this study, are shown in figures. (GSC) [de

  14. Dielectronic recombination of Be-like Fe ion

    International Nuclear Information System (INIS)

    Moribayashi, Kengo; Kato, Takako.

    1996-04-01

    Energy level(E), radiative transition probability(Ar), and autoionization rate(Aa) for Be-like Fe 22+ ion are calculated with use of Cowan's code. Using these atomic data, the dielectronic recombination rate coefficient(α) to the excited states and the intensity factor(Qd) of the dielectronic satellite lines have been calculated. The doubly excited states 1s 2 3lnl' as well as the 1s 2 2pnl of Fe 22+ ion are considered. The results are given in tables and figures. The n- and l-dependence for Ar, Aa, and α is studied. With use of it, Aa and Ar at large n are extrapolated. The dielectronic recombination processes from the 1s 2 2pnl and those from the 1s 2 3lnl' dominate at low and at high temperature, respectively. The qualitative different behaviors for E, Ar, and α between Be-like ions and He-like ions are discussed with use of atomic nuclear charge scaling. (author)

  15. Discovery of the double Doppler-shifted emission-line systems in the X-ray spectrum of SS 433

    Science.gov (United States)

    Kotani, Taro; Kawai, Nobuyuki; Aoki, Takashi; Doty, John; Matsuoka, Masaru; Mitsuda, Kazuhisa; Nagase, Fumiaki; Ricker, George; White, Nick E.

    1994-01-01

    We have used the CCD X-ray spectrometers on ASCA and resolved the X-ray emission line from the jet of SS 433 both into Doppler-shifted components with two distinct velocities, and into emission from different ionization states of iron, i.e., Fe XXV and Fe XXVI. This is the first direct detection of the two Doppler shifted beams in the X-ray spectra of SS 433 and allows the radial velocity of the jet along the line of sight to be determined with an accuracy comparable to the optical spectroscopy. We also found pairs of emission lines from other atomic species, such as ionized silicon and sulfur, with the Doppler shifts consistent with each other. This confirms the origin of the X-ray emission in the high temperature plasma in the jets.

  16. Radioiodination of cyclin dependent kinase inhibitor Olomoucine loaded Fe rate at Au nanoparticle and evaluation of the therapeutic efficacy on cancerous cells

    Energy Technology Data Exchange (ETDEWEB)

    Takan, Gokhan; Guldu, Ozge Kozgus; Medine, Emin Ilker [Ege Univ., Izmir (Turkey). Dept. of Nuclear Applications

    2017-06-01

    Magnetic nanoparticles have promising biomedical applications such as drug delivery, novel therapeutics and diagnostic imaging. Magnetic drug delivery combination works on the delivery of magnetic nanoparticles loaded with drug to the target tissue by means of an external magnetic field. Gold coated iron oxide (Fe rate at Au) nanoparticles can provide useful surface chemistry and biological reactivity. Covalent conjugation to the Fe rate at Au nanoparticles through cleavable linkages can be used to deliver drugs to tumor cells, then the drug can be released by an external. In this paper, purine based cyclin dependent kinases (CDKs) inhibitor Olomoucine (Olo) [2-(Hydroxyethylamino)-6-benzylamino-9-methylpurine] was loaded on gold coated iron oxide (Fe rate at Au) nanoparticles and radiolabeled with {sup 131}I to combine magnetic targeted drug delivery and radiotherapy. Fe rate at Au nanoparticles were synthesized by microemulsion method. The characterization of nanoparticles was examined by TEM, VSM and XRD. Amine activation was utilized by cysteamine hydrochloride and then CDI was used for conjugation of Olomoucine. Antiproliferative effect and cytotoxicity of Olomoucine loaded Fe rate at Au nanoparticles (Fe rate at Au-Olo) were investigated on MCF7 and A549 cell lines. Proliferation rate was decreased while uptake of Fe rate at Au-Olo on both cell lines was high in comparison with Olomoucine. Also, enhanced incorporation ratio was observed under external magnetic field.

  17. Radioiodination of cyclin dependent kinase inhibitor Olomoucine loaded Fe rate at Au nanoparticle and evaluation of the therapeutic efficacy on cancerous cells

    International Nuclear Information System (INIS)

    Takan, Gokhan; Guldu, Ozge Kozgus; Medine, Emin Ilker

    2017-01-01

    Magnetic nanoparticles have promising biomedical applications such as drug delivery, novel therapeutics and diagnostic imaging. Magnetic drug delivery combination works on the delivery of magnetic nanoparticles loaded with drug to the target tissue by means of an external magnetic field. Gold coated iron oxide (Fe rate at Au) nanoparticles can provide useful surface chemistry and biological reactivity. Covalent conjugation to the Fe rate at Au nanoparticles through cleavable linkages can be used to deliver drugs to tumor cells, then the drug can be released by an external. In this paper, purine based cyclin dependent kinases (CDKs) inhibitor Olomoucine (Olo) [2-(Hydroxyethylamino)-6-benzylamino-9-methylpurine] was loaded on gold coated iron oxide (Fe rate at Au) nanoparticles and radiolabeled with "1"3"1I to combine magnetic targeted drug delivery and radiotherapy. Fe rate at Au nanoparticles were synthesized by microemulsion method. The characterization of nanoparticles was examined by TEM, VSM and XRD. Amine activation was utilized by cysteamine hydrochloride and then CDI was used for conjugation of Olomoucine. Antiproliferative effect and cytotoxicity of Olomoucine loaded Fe rate at Au nanoparticles (Fe rate at Au-Olo) were investigated on MCF7 and A549 cell lines. Proliferation rate was decreased while uptake of Fe rate at Au-Olo on both cell lines was high in comparison with Olomoucine. Also, enhanced incorporation ratio was observed under external magnetic field.

  18. Al/Fe isomorphic substitution versus Fe{sub 2}O{sub 3} clusters formation in Fe-doped aluminosilicate nanotubes (imogolite)

    Energy Technology Data Exchange (ETDEWEB)

    Shafia, Ehsan [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy); Esposito, Serena [Università degli Studi di Cassino e del Lazio Meridionale, Department of Civil and Mechanical Engineering (Italy); Manzoli, Maela; Chiesa, Mario [Università di Torino, Dipartimento di Chimica and Centro Interdipartimentale NIS (Italy); Tiberto, Paola [Electromagnetism, I.N.Ri.M. (Italy); Barrera, Gabriele [Università di Torino, Dipartimento di Chimica and Centro Interdipartimentale NIS (Italy); Menard, Gabriel [Harvard University, Department of Chemistry and Chemical Biology (United States); Allia, Paolo, E-mail: paolo.allia@polito.it [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy); Freyria, Francesca S. [Massachusetts Institute of Technology, Department of Chemistry (United States); Garrone, Edoardo; Bonelli, Barbara, E-mail: barbara.bonelli@polito.it [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy)

    2015-08-15

    Textural, magnetic and spectroscopic properties are reported of Fe-doped aluminosilicate nanotubes (NTs) of the imogolite type, IMO, with nominal composition (OH){sub 3}Al{sub 2−x}Fe{sub x}O{sub 3}SiOH (x = 0, 0.025, 0.050). Samples were obtained by either direct synthesis (Fe-0.025-IMO, Fe-0.050-IMO) or post-synthesis loading (Fe-L-IMO). The Fe content was either 1.4 wt% (both Fe-0.050-IMO and Fe-L-IMO) or 0.7 wt% (Fe-0.025-IMO). Textural properties were characterized by High-Resolution Transmission Electron Microscopy, X-ray diffraction and N{sub 2} adsorption/desorption isotherms at 77 K. The presence of different iron species was studied by magnetic moment measurements and three spectroscopies: Mössbauer, UV–Vis and electron paramagnetic resonance, respectively. Fe{sup 3+}/Al{sup 3+} isomorphic substitution (IS) at octahedral sites at the external surface of NTs is the main process occurring by direct synthesis at low Fe loadings, giving rise to the formation of isolated high-spin Fe{sup 3+} sites. Higher loadings give rise, besides IS, to the formation of Fe{sub 2}O{sub 3} clusters. IS occurs up to a limit of Al/Fe atomic ratio of ca. 60 (corresponding to x = 0.032). A fraction of the magnetism related to NCs is pinned by the surface anisotropy; also, clusters are magnetically interacting with each other. Post-synthesis loading leads to a system rather close to that obtained by direct synthesis, involving both IS and cluster formations. Slightly larger clusters than with direct synthesis samples, however, are formed. The occurrence of IS indicates a facile cleavage/sealing of Al–O–Al bonds: this opens the possibility to exchange Al{sup 3+} ions in pre-formed IMO NTs, a much simpler procedure compared with direct synthesis.

  19. Diffusion of Nb in Fe and in some Fe alloys

    International Nuclear Information System (INIS)

    Kurokawa, S.; Ruzzante, J.E.; Hey, A.M.; Dyment, F.

    1981-01-01

    Diffusion data of microalloying elements such as Nb, V, Ti, are required when analysing the transformation and recrystallization behaviour of HSLA steels in order to optimize grain refinement and precipitation hardening. The diffusion behaviour of Nb in pure Fe, Fe 1.5 Mn, Fe 0.6 Si and Fe 1.5 Mn 0.6 Si has been measured between 1080 and 1200 0 C. Results indicate that Si increases Nb diffusivity while Mn decreases it. The sequence of diffusion coeficients values is: D sup(Nb) sub(Fe 1.5 Mn) [pt

  20. Magnetic and thermal properties of amorphous TbFeCo alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke, E-mail: K.Wang@hqu.edu.cn; Dong, Shuo; Huang, Ya; Qiu, Yuzhen

    2017-07-15

    Highlights: • Significant increase in magnetization is observed in TbFeCo upon crystallization. • The crystallization temperature is determined in the range between 400 and 450 °C. • The activation barriers for structural changes are obtained successfully. • Better thermal stability against crystallization and oxidation is demonstrated in FeCo-rich sample than Tb-rich type. - Abstract: Amorphous TbFeCo material with perpendicular magnetic anisotropy is currently attracting more attention for potential applications in spintronic devices and logic memories. We systematically investigate magnetic, structural, thermal, optical and electrical properties of TbFeCo alloy films. It shows out-of-plane easy axis of the films turns into in-plane orientation after annealing. Significant increase in saturation magnetization in the temperature range between 400 and 450 °C is revealed by thermomagnetic measurements. The occurrence of crystallization and oxidation at high temperatures is confirmed by X-ray diffraction measurements. Pronounced changes in optical reflectance and sheet resistance are observed with temperature, in line with structural relaxation and change. The activation barriers for crystallization and oxidation are determined to be 1.01 eV and 0.83 eV, respectively, for FeCo-rich and Tb-rich samples. Better thermal stability against crystallization and oxidation is demonstrated in the FeCo-rich sample than the Tb-rich type. Our results provide some useful information for the alloy used in device fabrication.

  1. First principles calculations of the magnetic and hyperfine properties of Fe/N/Fe and Fe/O/Fe multilayers in the ground state of cohesive energy

    Science.gov (United States)

    dos Santos, A. V.; Samudio Pérez, C. A.; Muenchen, D.; Anibele, T. P.

    2015-01-01

    The ground state properties of Fe/N/Fe and Fe/O/Fe multilayers were investigated using the first principles calculations. The calculations were performed using the Linearized Augmented Plane Wave (LAPW) method implemented in the Wien2k code. A supercell consisting of one layer of nitride (or oxide) between two layers of Fe in the bcc structure was used to model the structure of the multilayer. The research in new materials also stimulated theoretical and experimental studies of iron-based nitrides due to their variety of structural and magnetic properties for the potential applications as in high strength steels and for high corrosion resistance. It is obvious from many reports that magnetic iron nitrides such as γ-Fe4N and α-Fe16N2 have interesting magnetic properties, among these a high magnetisation saturation and a high density crimp. However, although Fe-N films and multilayers have many potential applications, they can be produced in many ways and are being extensively studied from the theoretical point of view there is no detailed knowledge of their electronic structure. Clearly, efforts to understand the influence of the nitrogen atoms on the entire electronic structure are needed as to correctly interpret the observed changes in the magnetic properties when going from Fe-N bulk compounds to multilayer structures. Nevertheless, the N atoms are not solely responsible for electronics alterations in solid compounds. Theoretical results showed that Fe4X bulk compounds, where X is a variable atom with increasing atomic number (Z), the nature of bonding between X and adjacent Fe atoms changes from more covalent to more ionic and the magnetic moments of Fe also increase for Z=7, i.e. N. This is an indicative that atoms with a Z number higher than 7, i.e., O, can produce several new alterations in the entire magnetic properties of Fe multilayers. This paper presents the first results of an ab-initio electronic structure calculations, performed for Fe-N and Fe

  2. Influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers, Fe/Cr/Fe- and Fe/MgO/Fe multilayers; Untersuchung der Morphologie und magnetische Eigenschaften von ionenstrahl-gesputterten Eisen-Einzelschichten, Fe/Cr/Fe- und Fe/MgO/Fe-Schichtsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Steeb, Alexandra

    2007-04-05

    In this PhD Thesis, the influence of the surface topography, morphology and structure on magnetic properties of ion beam sputtered iron layers on GaAs is examined. To analyze the structure of the produced iron films, low energy electron diffraction and scanning tunneling microscopy is employed. The utilized methods to investigate the magnetic properties are Kerr- and SQUID-magnetometry and ferromagnetic resonance. It is demonstrated that on untreated as well as on presputtered and heated GaAs substrates the sputtered iron films grow epitaxially. The least surface roughness of 1 A exhibit iron films grown on untreated GaAs, while iron films on heated GaAs have the highest roughness of 30 A. The largest crystal anisotropy constant is found for the presputtered GaAs/Fe-System. For this preparation method, two monolayers of iron are determined to be magnetically dead layers. At a film thickness of 100 A, 83% of the value for saturation magnetization of bulk iron are achieved. The small observed FMR-linewidths confirm the good bulk properties of the ion beam sputtered iron. Furthermore, an antiferromagnetic interlayer exchange coupling in sputtered Fe/Cr/Fe-films was achieved. For a thickness of 12 to 17 A of the chrome interlayer, a coupling strength up to 0.2 mJ/m{sup 2} is found. To account for the small coupling strength, a strong intermixing at the interface is assumed. Finally, epitaxial Fe/MgO/Fe/FeMn multilayers are deposited on GaAs. After the structuring, it is possible to detect tunneling processes in the tunneling contacts with current-voltage measurements. The tunnel magneto resistance values of 2% are small, which can be explained by the absence of sharp, well-defined interfaces between the Fe/FeMn and the Fe/MgO interfaces. These results demonstrate, that analog to MBE the ion beam sputtering method realizes good magnetic bulk properties. However, interface sensitive phenomena are weakened because of a strong intermixing at the interfaces. (orig.)

  3. Electroluminescence properties of Si MOS structures with incorporation of FeSi2 precipitates formed by iron implantation

    International Nuclear Information System (INIS)

    Chow, C.F.; Wong, S.P.; Gao, Y.; Ke, N.; Li, Q.; Cheung, W.Y.; Lourenco, M.A.; Homewood, K.P.

    2005-01-01

    Silicon MOS structures with FeSi 2 precipitates embedded in the MOS active region have been fabricated and the electroluminescence (EL) properties from these FeSi 2 -Si MOS structures were measured as a function of temperature from 80 K to 300 K. Clear EL signals were observed even at room temperature for samples prepared at appropriate processing conditions. The EL spectra consist of two peaks, one attributed to FeSi 2 and the other attributed to Si band edge emission. While the intensity of the FeSi 2 peak showed the usual thermal quenching behavior, the Si band edge emission showed the opposite trend with its intensity increased with increasing temperature. Details of the line shapes and their temperature dependence are analyzed and discussed

  4. The decay modes of proton drip-line nuclei with A between 42 and 47

    International Nuclear Information System (INIS)

    Borrel, V.; Dogny, S.; Guillemaud-Mueller, D.; Mueller, A.C.; Pougheon, F.; Sorlin, O.; Bazin, D.; Del Moral, R.; Dufour, J.P.; Faux, L.; Fleury, A.; Hubert, F.; Marchand, C.; Pravikoff, M.S.; Chubarian, G.G.

    1992-01-01

    Neutron-deficient isotopes with Z = 21 to 26 have been produced as projectile-like fragments of an intense 58 Ni GANIL beam of 69 MeV/nucleon. The nuclei selected by the upgraded LISE3 spectrometer were identified and implanted in a silicon detector telescope. The 43 Cr, 47 Fe and 46 Fe isotopes were identified for the first time whereas 45 Fe, 45 Mn, 44 Mn and 42 V were not observed, indicating probable instability of these nuclei against particle emission. Measurements of the half-lives of 43 Cr and 46 Mn have been performed and the analysis of their measured beta-delayed proton spectra has given, through the Isobaric Multiplet Mass Equation, an empirical estimation of their masses. Half-lives of 44 Cr, 43 V, 47 Fe and 46 Fe have also been measured. A discussion of various mass predictions for nuclei at the proton drip-line is given

  5. Gnevyshev peaks in solar radio emissions at different frequencies

    Directory of Open Access Journals (Sweden)

    R. P. Kane

    2009-04-01

    Full Text Available Sunspots have a major 11-year cycle, but the years near the sunspot maximum show two or more peaks called GP (Gnevyshev Peaks. In this communication, it was examined whether these peaks in sunspots are reflected in other parameters such as Lyman-α (the chromospheric emission 121.6 nm, radio emissions 242–15 400 MHz emanating from altitude levels 2000–12 000 km, the low latitude (+45° to −45° solar open magnetic flux and the coronal green line emission (Fe XIV, 530.3 nm. In the different solar cycles 20–23, the similarity extended at least upto the level of 609 MHz, but in cycle 22, the highest level was of 242 MHz. The extension to the higher level in cycle 22 does not seem to be related to the cycle strength Rz(max, or to the cycle length.

  6. HYDROGEN PERMITTED LINES IN THE FIRST NEAR-IR SPECTRA OF Th 28 MICROJET: ACCRETION OR EJECTION TRACERS?

    International Nuclear Information System (INIS)

    Coffey, Deirdre; Podio, Linda; Bacciotti, Francesca; Nisini, Brunella

    2010-01-01

    We report the first near-infrared detection of the bipolar microjet from T Tauri star ThA 15-28 (hereafter Th 28). Spectra were obtained with Very Large Telescope (VLT)/ISAAC for the slit both perpendicular and parallel to the flow to examine jet kinematics and gas physics within the first arcsecond from the star. The jet was successfully detected in both molecular and atomic lines. The H 2 component was found to be entirely blueshifted around the base of the bipolar jet. It shows that only the blue lobe is emitting in H 2 while light is scattered in the direction of the red lobe, highlighting an asymmetric extinction and/or excitation between the two lobes. Consistent with this view, the red lobe is brighter in all atomic lines. Interestingly, the jet was detected not only in [Fe II], but also in Brγ and Paβ lines. Though considered tracers mainly of accretion, we find that these high excitation hydrogen permitted lines trace the jet as far as 150 AU from the star. This is confirmed in a number of ways: the presence of the [Fe II] 2.13 μm line which is of similarly high excitation; H I velocities which match the jet [Fe II] velocities in both the blue and red lobe; and high electron density close to the source of >6 x 10 4 cm -3 derived from the [Fe II] 1.64, 1.60 μm ratio. These near-infrared data complement Hubble Space Telescope Imaging Spectrograph (HST/STIS) optical and near-ultraviolet data for the same target which were used in a jet rotation study, although no rotation signature could be identified here due to insufficient angular resolution. The unpublished HST/STIS Hα emission is included here alongside the other H I lines. Identifying Brγ and Paβ as tracers of ejection is significant because of the importance of finding strong near-infrared probes close to the star, where forbidden lines are quenched, which will help understand accretion ejection when observed with high spatial resolution instruments such as VLTI/AMBER.

  7. Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction

    Directory of Open Access Journals (Sweden)

    Lukas P. Feilen

    2017-05-01

    Full Text Available Physiological function and pathology of the Alzheimer’s disease causing amyloid precursor protein (APP are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs. The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.

  8. Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction.

    Science.gov (United States)

    Feilen, Lukas P; Haubrich, Kevin; Strecker, Paul; Probst, Sabine; Eggert, Simone; Stier, Gunter; Sinning, Irmgard; Konietzko, Uwe; Kins, Stefan; Simon, Bernd; Wild, Klemens

    2017-01-01

    Physiological function and pathology of the Alzheimer's disease causing amyloid precursor protein (APP) are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs). The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD) including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR) techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.

  9. Formation mechanisms of neutral Fe layers in the thermosphere at Antarctica studied with a thermosphere-ionosphere Fe/Fe+ (TIFe) model

    Science.gov (United States)

    Chu, Xinzhao; Yu, Zhibin

    2017-06-01

    With a thermosphere-ionosphere Fe/Fe+ (TIFe) model developed from first principles at the University of Colorado, we present the first quantitative investigation of formation mechanisms of thermospheric Fe layers observed by lidar in Antarctica. These recently discovered neutral metal layers in the thermosphere between 100 and 200 km provide unique tracers for studies of fundamental processes in the space-atmosphere interaction region. The TIFe model formulates and expands the TIFe theory originally proposed by Chu et al. that the thermospheric Fe layers are produced through the neutralization of converged Fe+ layers. Through testing mechanisms and reproducing the 28 May 2011 event at McMurdo, we conceive the lifecycle of meteoric metals via deposition, transport, chemistry, and wave dynamics for thermospheric Fe layers with gravity wave signatures. While the meteor injection of iron species is negligible above 120 km, the polar electric field transports metallic ions Fe+ upward from their main deposition region into the E-F regions, providing the major source of Fe+ (and accordingly Fe) in the thermosphere. Atmospheric wave-induced vertical shears of vertical and horizontal winds converge Fe+ to form dense Fe+ layers. Direct electron-Fe+ recombination is the major channel to neutralize Fe+ layers to form Fe above 120 km. Fe layer shapes are determined by multiple factors of neutral winds, electric field, and aurora activity. Gravity-wave-induced vertical wind plays a key role in forming gravity-wave-shaped Fe layers. Aurora particle precipitation enhances Fe+ neutralization by increasing electron density while accelerating Fe loss via charge transfer with enhanced NO+ and O2+ densities.Plain Language SummaryThe discoveries of neutral metal layers reaching near 200 km in the thermosphere have significant scientific merit because such discoveries challenge the current understandings of upper atmospheric composition, chemistry, dynamics, electrodynamics, and

  10. Low temperature Moessbauer study of amorphous Fe83B17

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.

    1987-01-01

    Information about changes in magnetic structures of metallic glass Fe 83 B 17 at low temperatures has been obtained by 57 Fe Moessbauer spectroscopy in the temperature range from 295 to 77 K. The mean values of the magnetic hyperfine field have been calculated from magnetic splitting of Moessbauer spectra. The angle between the direction of magnetization and the γ-ray direction θ obtained from line intensity ratios is given as a function of temperature. The curve shows a minimum at 120 K. The influence of decreasing temperature on the magnetic structure may be caused by a change in magnetic anisotropy and a reorientation of surface spins. The main contribution to the changes in θ comes from the reorientation of surface domains

  11. Effects of Fe fine powders doping on hot deformed NdFeB magnets

    International Nuclear Information System (INIS)

    Lin, Min; Wang, Huijie; Zheng, Jingwu; Yan, Aru

    2015-01-01

    The composite NdFeB magnets with blending melt-spun flakes and Fe fine powders were prepared by the hot-pressed and hot-deformed route. Characterizations of the hot-deformed NdFeB magnets affected by the doped Fe powders were tested. The doped Fe powders decrease the hot-deformed pressure when the strain is between 15 and 50%. XRD patterns show that the doped Fe powders have little influence on the c-axis alignment of hot-deformed NdFeB magnets in the press direction. The B r and the (BH) max get improved when the doped Fe powders are less than 3 wt%. The doped Fe of hot-deformed NdFeB magnets exists in the elongated state and the spherical state surrounded by the Nd-rich phase. With the Fe fraction increasing, the potential of magnet moves to the positive direction and the diameter of the Nyquist arc becomes larger, which indicate that the corrosion resistance improved effectively. The bending strength was enhanced by the elongated α-Fe phase embedded in the matrix 2:14:1 phase. - Highlights: • The doped Fe powders have little influence on the c-axis alignment of magnets. • The elongated Fe powders are more than the spherical Fe powders in the magnets. • The corrosion resistance is improved effectively with the increasing Fe fraction. • The bending strength is enhanced by the elongated α-Fe phase embedded in the matrix

  12. Effects of Fe fine powders doping on hot deformed NdFeB magnets

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Min, E-mail: linm@nimte.ac.cn [Ningbo Institute of Material Technology & Engineering Chinese Academy of Science, Ningbo 315201 (China); Wang, Huijie [Ningbo Jinji Strong Magnetic Material Company, Ningbo 315041 (China); Zheng, Jingwu [Zhejiang University of Technology, Hangzhou 310014 (China); Yan, Aru [Ningbo Institute of Material Technology & Engineering Chinese Academy of Science, Ningbo 315201 (China)

    2015-04-01

    The composite NdFeB magnets with blending melt-spun flakes and Fe fine powders were prepared by the hot-pressed and hot-deformed route. Characterizations of the hot-deformed NdFeB magnets affected by the doped Fe powders were tested. The doped Fe powders decrease the hot-deformed pressure when the strain is between 15 and 50%. XRD patterns show that the doped Fe powders have little influence on the c-axis alignment of hot-deformed NdFeB magnets in the press direction. The B{sub r} and the (BH){sub max} get improved when the doped Fe powders are less than 3 wt%. The doped Fe of hot-deformed NdFeB magnets exists in the elongated state and the spherical state surrounded by the Nd-rich phase. With the Fe fraction increasing, the potential of magnet moves to the positive direction and the diameter of the Nyquist arc becomes larger, which indicate that the corrosion resistance improved effectively. The bending strength was enhanced by the elongated α-Fe phase embedded in the matrix 2:14:1 phase. - Highlights: • The doped Fe powders have little influence on the c-axis alignment of magnets. • The elongated Fe powders are more than the spherical Fe powders in the magnets. • The corrosion resistance is improved effectively with the increasing Fe fraction. • The bending strength is enhanced by the elongated α-Fe phase embedded in the matrix.

  13. Measurement of the Radiative Decay of the Longest-Lived Level in the Fe XVII Spectrum

    Science.gov (United States)

    Brown, Gregory V.; Beiersdorfer, Peter; Träbert, Elmar

    2014-08-01

    The Fe XVII emission spectrum comprises several very prominent X-ray lines that play an important role in the study of many astrophysical objects. Among the Fe XVII X-ray lines, those emanating from a 3s level, i.e., lines 3F, 3G, and M2, invariably appear too strong compared to the lines emanating from a 3d level, i.e., lines 3C and 3D, when compared to theory. Two of the four 3s levels are metastable, which means they have a rather long radiative decay time compared to collisional processes. The decay rate of the 2p^53s J=2 level has recently been measured at the Livermore EBIT facility [J. R. Crespo López-Urrutia and P. Beiersdorfer, ApJ 721, 576 (2010)], and the scatter of predictions by a factor of 1.7 has been reduced to a measurement uncertainty of merely a few percent. Even longer-lived is the J=0 level of the same 2p^53s configuration. Theory predicts an exclusive magnetic dipole decay to the lowest J=1 level of the same 2p^53s configuration, i.e. to the upper level of line 3G. There appear to be fewer predictions for this rate than for the rates associated with the other Fe XVII levels. Various calculations yield a decay rate near 16 000 s-1 for this level (or a level lifetime near 63 µs). If this value is correct, electron-impact collisions affect line ratios tied to this level at densities between about 10^10 cm-3 and 10^13 cm-3, that is, exactly at many coronal densities of present interest. We have used the Livermore EBIT facility to measure the M1 decay rate of the 2p^53s J=0 level. We find a value commensurate with the value predicted by the Flexible Atomic Code.Work performed under auspices of U.S. D.o.E. by DE-AC52-07NA27344 and supported by NASA's APRA progam under Interagency Agreement NNG13WF991.

  14. comparison of elastic-plastic FE method and engineering method for RPV fracture mechanics analysis

    International Nuclear Information System (INIS)

    Sun Yingxue; Zheng Bin; Zhang Fenggang

    2009-01-01

    This paper described the FE analysis of elastic-plastic fracture mechanics for a crack in RPV belt line using ABAQUS code. It calculated and evaluated the stress intensity factor and J integral of crack under PTS transients. The result is also compared with that by engineering analysis method. It shows that the results using engineering analysis method is a little larger than the results using FE analysis of 3D elastic-plastic fracture mechanics, thus the engineering analysis method is conservative than the elastic-plastic fracture mechanics method. (authors)

  15. Paisaje forestal y representación social en Castilla (siglos XIV-XVI. Los montes de San Salvador de Oña (Burgos

    Directory of Open Access Journals (Sweden)

    Francisco REYES TÉLLEZ

    2014-12-01

    Full Text Available El objetivo principal de este artículo es tratar de analizar la representación social del paisaje forestal perteneciente al señorío del monasterio de San Salvador de Oña (Burgos, durante los siglos XIV-XVI, a partir de las descripciones que se realizan del mismo en la documentación judicial relacionada con pleitos, pesquisas, etc. por el uso y aprovechamiento de los bosques y montes, para procurar conocer cuál era la construcción simbólica de esos paisajes de los distintos agentes sociales, e intentar valorar si esa forma de aproximarnos al territorio nos puede aportar nuevos enfoques o posibilidades de interpretación en el estudio de esa realidad.

  16. Impacts of yttrium substitution on FMR line-width and magnetic properties of nickel spinel ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ishaque, M., E-mail: ishaqdgk1@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Ali, Irshad; Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Iqbal, M. Asif [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); College of E & ME, National University of Science and Technology, Islamabad (Pakistan); Islam, M.U. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2015-05-15

    The influence of yttrium (Y) substitution on ferromagnetic resonance (FMR), initial permeability, and magnetic properties of NiFe{sub 2}O{sub 4} ferrites were investigated. It was observed that the FMR line-width decreases with yttrium contents for the substitution level 0≤×≤0.06. Beyond this, the FMR line-width increases with yttrium contents. The nominal composition NiY{sub 0.12}Fe{sub 1.88}O{sub 4} exhibited the smallest FMR line-width ~282 Oe. A significant change in FMR position of nickel–yttrium (Ni–Y) ferrites was observed and it found to exist between 4150 and 4600 Oe. The saturation magnetization was observed to decrease with the increase of yttrium contents and this was referred to the redistribution of cations on octahedral. The coercivity increased from 15 Oe to 59 Oe by increasing the yttrium concentration. The initial permeability decreased from 110 to 35 at 1 MHz by the incorporation of yttrium and this was attributed to the smaller grains which may obstruct the domain wall movement and impede the domain wall motion. The magnetic loss factors of substituted samples exhibit decreasing behavior in the frequency range 1 kHz to 10 MHz. The smaller FMR line-width and reduced magnetic loss factor of the investigated samples suggest the possible use of these materials in high frequency applications. - Highlights: • Influence of Y{sup 3+} substitution on the properties of nickel ferrites is investigated. • Very small FMR line-width (282 Oe) is exhibited by these substituted ferrites. • Fourfold increase in coercivity was observed for NiY{sub 0.24}Fe{sub 1.76}O{sub 4} ferrites.

  17. Pr2Fe14B/α-Fe nanocomposites for thermal applications

    International Nuclear Information System (INIS)

    Silva, Suelanny Carvalho da

    2012-01-01

    In this work, Pr x Fe 94 - x B 6 (x = 6, 8, 10 and 12) nanostructured powders were prepared by a combination of hydrogenation, disproportionation, desorption and recombination (HDDR) process with high energy milling applied to the mixture of an as-cast alloy (Pr 14 Fe 80 B 6 ) and α-Fe. The produced nanoparticles showed magnetic properties comparable to those reported in hyperthermia studies. The optimal time to obtain the magnetic nanoparticles is 5 hours (at 900 rpm). It was verified that longer milling times cause an increase in carbon percentage on the particles. The carbon is derived from oleic acid added as a surfactant in the milling step. The nanocomposites exhibit coercive force ranging from 80 Oe (6.5 kAm -1 ) to 170 Oe (13.5 kAm -1 ) and magnetic moments in the range of 81 129 Am2kg -1 . From the X-ray diffraction analyses, only two phases were found in all samples: α-Fe and the magnetic phase Pr 2 Fe 14 B. Individual nanoparticles with diameter of about 20 nm were verified. The samples studied presented heating when exposed to an alternating magnetic field (f = 222 kHz e H max ∼3.7 kAm -1 ) comparable to reported in literature. Temperature variations (ΔT) of the powders were: 51 K for Pr 6 Fe 88 B 6 , 41 K for Pr 8 Fe 86 B 6 , 38 K for Pr 10 Fe 8 4 B 6 and T = 34 K for Pr 12 Fe 82 B 6 . The specific absorption rates (SARs) of the powders were 201 Wkg -1 for Pr 6 Fe 88 B 6 composition, 158 Wkg -1 on the composition Pr 8 Fe 86 B 6 , and 114 Wkg -1 for Pr 10 Fe 84 B 6 and Pr 12 Fe 82 B 6 compositions. (author)

  18. Microstructure and properties of multiphase sintered cermets Fe-Fe2B

    International Nuclear Information System (INIS)

    Nowacki, J.; Klimek, L.

    1998-01-01

    The process of multiphase sintering of iron in the vacuum has been analysed. As a result of the process iron-iron boride cermets have been produced. Fe-Fe 2 B cermets were obtained as a result of sintering of the Fe and B pure elements in the vacuum. Attemps at sintering in the solid phase and with the participation of the liquid phase, the Fe-Fe 2 B eutectic, have been made. Metallographic qualitative and quantitative studies, X-ray structural qualitative and qauantitative analysis allowed to determine the structure of Fe 2 B cermets, as well as a description of the kinetics of quantitative changes in phase proportions in the course of sintering. It has been found that their structure varies widely depending on sintering parameters and the composition of the sinters. Measurements of the Fe-Fe 2 B cermets hardness and measurements on wear during dry friction by the pin-on-disc method have shown distinct advantages of the cermets as a modern constructional materials. The hardness of Fe-Fe 2 B cermets, depending on their chemical composition and sintering parameters, ranges widely from 150 to 1500 HV, and their resistance to wear is comparable to that of diffusively boronized steels. FeFe 2 B cermets are a composite material in which iron boride, Fe 2 B, with a hardness of about 1800 HV plays the role of the reinforcement,while iron-iron boride, Fe-Fe 2 B, with a hardness of about 500 HV plays the role of matrix. The eutectic in the spaces between iron boride grains is composed of boron solid solution plates in iron with a hardness of arround 250 HV, and iron boride, Fe 2 B, plates with a hardness of approximaly 1800 HV. The combination of such different materials, a hard reinforcement and a relatively plastic matrix produces favourable properties of the cermet thus produced high hardness (1500 HV) constant over whole cross section of the material, resistance of abrasive wear and acceptable ductility. The properties mentioned above, resulting from the cermet

  19. Tuning high frequency magnetic properties and damping of FeGa, FeGaN and FeGaB thin films

    Directory of Open Access Journals (Sweden)

    Derang Cao

    2017-11-01

    Full Text Available A series of FeGa, FeGaN and FeGaB films with varied oblique angles were deposited by sputtering method on silicon substrates, respectively. The microstructure, soft magnetism, microwave properties, and damping factor for the films were investigated. The FeGa films showed a poor high frequency magnetic property due to the large stress itself. The grain size of FeGa films was reduced by the additional N element, while the structure of FeGa films was changed from the polycrystalline to amorphous phase by the involved B element. As a result, N content can effectively improve the magnetic softness of FeGa film, but their high frequency magnetic properties were still poor both when the N2/Ar flow rate ratio is 2% and 5% during the deposition. The additional B content significantly led to the excellent magnetic softness and the self-biased ferromagnetic resonance frequency of 1.83 GHz for FeGaB film. The dampings of FeGa films were adjusted by the additional N and B contents from 0.218 to 0.139 and 0.023, respectively. The combination of these properties for FeGa films are helpful for the development of magnetostrictive microwave devices.

  20. Controlled reduction of LaFe xMn yMo zO3/Al2O3 composites to produce highly dispersed and stable Fe0 catalysts: a Mössbauer investigation

    Directory of Open Access Journals (Sweden)

    Juliana Cristina Tristão

    2008-06-01

    Full Text Available In this work, controlled reduction of perovskites supported on Al2O3 was used to prepare thermally stable nanodispersed iron catalysts based on Fe0/La2O3/Al2O3. The perovskites composites LaFe0.90Mn0.08Mo0.02O3(25, 33 and 50 wt (% /Al2O3 and LaFe0.90Mn0.1O3(25 wt (% /Al2O3 were prepared and characterized by XRD, BET, TPR, SEM and Mössbauer spectroscopy. XRD for unsupported perovskite showed the formation of a single phase perovskite structure. The Mössbauer spectra of the perovskites were fitted with hyperfine field distribution model for the perovskite. Supported perovskites on Al2O3 showed a decrease of the hyperfine field in respect to unsupported perovskite, due to decrease of particle size and dispersion of the Fe3+ specimens on the support. Also showed broaden lines and relaxation effects due to the small particle size. To produce the Fe0 catalyst, the composite perovskite(25%/Al2O3 was reduced with H2 at 900, 1000 and 1100 °C for 1 hour. XRD data indicated the formation of Fe0 catalyst with particles sizes of ca. 35 nm. The Mössbauer spectrum showed the formation of metallic iron and doublets corresponding to species of octahedric Fe2+ and Fe3+ sites dispersed on Al2O3. These catalysts showed improved stability towards sintering even upon treatment at 1000 and 1100 °C under H2.

  1. Spectrophotometric analysis of vitamin E using Cu(I)-Bathocuproine or/and Fe(II)-2,4,6-tris-(2'-pyridyl)-s-triazine complexes

    International Nuclear Information System (INIS)

    Devi, I.; Memon, S. A.; Khuhawar, M.Y.

    2004-01-01

    Vitamin E (tocopherols and tocotrienols) antioxidants are determined by reducing Cu(II) to Cu(I) or Fe(III) to Fe(II) in presence of vitamin E and subsequent complexation of Cu(I) with bathocuproine and/or Fe(II) with 2,4,6-tris-(2'-pyridyl)-s-triazine (TPTZ). Both the reactions are monitored separately, Cu(I)-bathocuproine at 479 nm where as, Fe(II)-(TPTZ) at 595 nm spectrophotometrically. Linear calibration curves are achieved for both complexes between I to 5mu g ml-1 for vitamin E. The methods were applied for the determination of vitamin E in pharmaceutical preparations and edible oils. Vitamin E, from edible oils, was solvent extracted into n-hexane prior to saponification. Furthermore, a single lined flow was also examined. A larger excess of Cu(II) or Fe =(II) with different concentrations of vitamin E in buffer pH 4 was run on the line and constant amounts of reagent bathocuproine or TPTZ in each case was injected through the injector. The peak height shows a linear relationship for vitamin E between 0.5 to 2.5 mu g ml-1 for both complexes. (author)

  2. Interparticle interactions of FePt core and Fe{sub 3}O{sub 4} shell in FePt/Fe{sub 3}O{sub 4} magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hossein, E-mail: Akbari.ph@iauardabil.ac.ir [Department of Physics, Ardabil Branch, Islamic Azad University, Ardabil (Iran, Islamic Republic of); Zeynali, Hossein [Department of Physics, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Bakhshayeshi, Ali [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

    2016-02-22

    Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. In FePt/Fe{sub 3}O{sub 4} core/shell system, core thickness is 2 nm and shell thickness varies from zero to 2.5 nm. A theoretical model presented to calculate the shell thickness dependence of Coercivity. Presented model is compared with the results from Stoner–Wohlfarth model to interpret the shell thickness dependence of Coercivity in FePt/Fe{sub 3}O{sub 4} core/shell nanoparticles. There is a difference between the results from Stoner–Wohlfarth model and experimental data when the shell thickness increases. In the presented model, the effects of interparticle exchange and random magneto crystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve a better agreement with experimental data. For magnetic shells in FePt/Fe{sub 3}O{sub 4} core/shell, effective coupling between particles increases with increasing shell thickness which leads to Coercivity destruction for stronger couplings. According to the boundary conditions, in the harder regions with higher exchange stiffness, there is small variation in magnetization and so the magnetization modes become more localized. We discussed both localized and non-localized magnetization modes. For non-zero shell thickness, non-localized modes propagate in the soft phase which effects the quality of particle exchange interactions. - Highlights: • Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. • Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. • A theoretical model presented to calculate the shell thickness dependence of Coercivity. • Magnetic shells increase effective coupling between particles with increasing shell thickness. • Magnetization modes are more localized in the regions with

  3. In vitro application of Fe/MgO nanoparticles as magnetically mediated hyperthermia agents for cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chalkidou, A. [Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece); Molecular Oncology Laboratory, Theagenio Cancer Hospital, Alexandrou Simeonidi Street 2, 54 007 Thessaloniki (Greece); Simeonidis, K. [Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece); Angelakeris, M., E-mail: agelaker@auth.g [Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece); Samaras, T. [Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece); Martinez-Boubeta, C. [Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, Barcelona 08028 (Spain); Balcells, Ll. [ICMAB-CSIC, Campus UAB, Bellaterra 08193 (Spain); Papazisis, K. [Molecular Oncology Laboratory, Theagenio Cancer Hospital, Alexandrou Simeonidi Street 2, 54 007 Thessaloniki (Greece); Dendrinou-Samara, C. [Department of Chemistry, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece); Kalogirou, O. [Department of Physics, Aristotle University of Thessaloniki, 54 124 Thessaloniki (Greece)

    2011-03-15

    In this work we study the heating efficiency of Fe/MgO magnetic core/biocompatible shell nanoparticles and their in vitro application in magnetic hyperthermia on cancer cells. Different human breast cancer cell lines were used to assess the suitability of nanoparticles for in vivo application. The experiments revealed a very good cytotoxicity profile and significant uptake efficiency together with relatively high specific absorption rates and fast thermal response, features that are crucial for adequate thermal efficiency and minimum duration of treatment. - Research highlights: > Fe/MgO magnetic core/shell nanoparticles and their in vitro application for magnetic hyperthermia. > Very good cytotoxicity profile and significant uptake efficiency in three human breast cancer cell lines. > SAR values and fast thermal response guarantee adequate thermal efficiency and minimum treatment duration.

  4. The ability of current micro-velocity models to represent center-limb line profiles

    International Nuclear Information System (INIS)

    Evans, J.C.; Testerman, L.

    1975-01-01

    Results are presented on the ability of microturbulences, LTE line formation and a homogeneous thermal model to realistically represent the center-limb variation of temporally and spacially averaged solar line profiles. Three somewhat similar semi-empirical thermal models have been used in combination with five current microturbulence models which cover the gamut of homogeneous-isotropic to nonhomogeneous-anisotropic. From high resolution photoelectric data for (lambdalambda 5000-6000 at five μ-values(1,0.63,0.4,0.25,0.16) obtained at KPNO, were selected 17 Fe I and 5 Fe II line profiles to be unblended and symmetrized for study. An iterative scheme has been developed to calculate theoretical profiles for the various combination of models and compare them to the observed profile using the abundance at each limb position and the magnitude of the pressure broadening at the center of the disc as parameters. It was found that a microturbulence model, for which the radial and tangential components increase into deeper layers with xisub(tan)>xisub(rad), produces a reasonable good center-limb fit for lines less than 100mA. However for lines stronger than 140mA, microturbulence models with no depth dependence produce the best match between theory and observation. Thus there is reason to question the uniqueness of the microturbulence concept. (Auth.)

  5. Strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy

    International Nuclear Information System (INIS)

    Shi, Guodong; Chen, Xiaohua; Jiang, Han; Wang, Zidong; Tang, Hao; Fan, Yongquan

    2015-01-01

    A single crystal Cu–Fe alloy with finely dispersed precipitate Fe nanoparticles was fabricated in this study. The interface relationship of iron nanoparticle and copper matrix was analyzed with a high-resolution transmission electron microscope (HRTEM), and the effect of Fe nanoparticles on mechanical properties of single crystal Cu–Fe alloy was discussed. Results show that, the finely dispersed Fe nanoparticles can be obtained under the directional solidification condition, with the size of 5–50 nm and the coherent interface between the iron nanoparticle and the copper matrix. Single crystal Cu–Fe alloy possesses improved tensile strength of 194.64 MPa, and total elongation of 44.72%, respectively, at room temperature, in contrast to pure Cu sample. Nanoparticles which have coherent interface with matrix can improve the dislocation motion state. Some dislocations can slip through the nanoparticle along the coherent interface and some dislocations can enter into the nanoparticles. Thus to improve the tensile strength of single crystal Cu–Fe alloy without sacrificing the ductility simultaneously. Based on the above analyses, strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy was described

  6. Quantum-electrodynamic influences on the lifetime of metastable states; Quantenelektrodynamische Einfluesse auf die Lebensdauer metastabiler Zustaende

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, G.

    2007-07-17

    High-precision lifetime measurements of the metastable 1s{sup 2}2s{sup 2}2p{sup 2}P{sup 0}{sub 3/2} level in boronlike Ar XIV and the 3s{sup 2}2p {sup 2}P{sup 0}{sub 3/2} level in aluminumlike Fe XIV were performed at the Heidelberg electron beam ion trap (HD-EBIT). The lifetimes were inferred by monitoring their optical decay curves resulting from the magnetic dipole (M1) transition 1s{sup 2}2s{sup 2}2p{sup 2}P{sup 0}{sub 3/2}-{sup 2}P{sup 0}{sub 1/2} and 3s{sup 2}3p {sup 2}P{sup 0}{sub 3/2}-{sup 2}P{sup 0}{sub 1/2} to the ground state configuration with transition wavelengths of 441.256 nm and 530.29 nm, respectively. Possible systematic error sources were investigated by studying the dependence of the decay times of the curves on various trapping conditions with high statistical significance. A new trapping scheme for lifetime measurements at an EBIT has been applied and allowed to reach an unprecedented precision in the realm of lifetime determinations on highly charged ions. The results of 9.573(4)({sup +12}{sub -5}) ms (stat)(syst) for Ar XIV and 16.726(10)(+17) ms (stat)(syst) for Fe XIV with a relative accuracy of 0.14% and 0.13%, respectively, make these measurements for the first time sensitive to quantum electrodynamic effects like the electron anomalous magnetic moment (EAMM). The results, improving the accuracy of previous measurements by factors of 10 and 6, respectively, show a clear discrepancy of about 3{sigma} and 4{sigma} to the trend of existing theoretical models, which in almost all cases predict a shorter lifetime, when adjusted for the EAMM. The obvious disagreement between experimental results and the predictions points at the incompleteness of the theoretical models used. (orig.)

  7. Experimental phases diagram Zr-Fe and Zr-Sn-Fe of the Fe rich zone at a temperature of 1100oC

    International Nuclear Information System (INIS)

    Nieva, N.; Jimenez, J.; Gomez, A; Granovsky, M.S

    2010-01-01

    Zr-based alloys are frequently used in the nuclear energy industry; among these are the Zr-based Zircaloys whose main alloys are Sn and Fe. In order to experimentally evaluate part of the diagram of the binary Zr-Fe phases and the ternary Zr-Sn-Fe in the Fe-rich zone, different binary alloys in the area closest to the composition of the ZrFe 2 and Zr 6 Fe 23 compounds were designed as well as a ternary alloy of Zr-Sn-Fe in the Fe-rich region of the ternary system. All the alloys underwent a two month heat treatment at a temperature of 1100 o C. Later the phases that were present were identified using different complementary techniques (mainly X-ray diffraction and microanalysis). The clear presence of the Zr 6 Fe 23 phase was not observed in any of the alloys. A new ternary phase consisting approximately of Zr 2 0Sn 14 Fe 66 was verified in the ternary alloy

  8. 57Fe Moessbauer spectroscopic characterisation of a ferromanganese nodule from the Central Indian Ocean

    International Nuclear Information System (INIS)

    Dutta, R.K.; Chakravortty, V.

    1997-01-01

    The iron bearing phases present in a ferromanganese nodule from the Central Indian Ocean have been determined using 57 Fe Moessbauer spectroscopy. The Moessbauer results have been corroborated by XRD, IR and TG-DTA studies. The Moessbauer spectrum of a ferromanganese nodule shows a broad line width which indicates the presence of more than one iron bearing paramagnetic oxide or oxyhydroxide phases where iron is present as Fe 3+ . γ-FeOOH has been distinctly characterised as one of the iron bearing phases in the nodule. Other oxyhydroxide and oxide phases of iron in the nodule have been ruled out. A typical paramagnetic doublet persists even at very high temperature which has been proposed to be due to iron(III)phosphate. Formation of solid solution of Mn 2 O 3 -Fe 2 O 3 has been observed in the heat treated nodule at 1073 K, which has been characterised by the Moessbauer technique. (author)

  9. Modification of interlayer exchange coupling in Fe/V/Fe trilayers using hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Skoryna, J., E-mail: jskoryna@ifmpan.poznan.pl [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland); Marczyńska, A. [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland); Lewandowski, M. [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85 St., 61-614 Poznań (Poland); Smardz, L. [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland)

    2015-10-05

    Highlights: • Magnetic films and multilayers. • Thin films. • Hydrogen absorbing materials. • Magnetic measurements. • Exchange coupling. - Abstract: Fe/V/Fe trilayers with constant-thickness Fe and step-like wedged V sublayers were prepared at room temperature using UHV magnetron sputtering. The bottom Fe layer grows onto oxidised Si(1 0 0) substrate and shows relatively high coercivity. The top Fe layer grows on vanadium spacer and shows considerably lower coercivity. The planar growth of the Fe and V sublayers was confirmed in-situ by X-ray photoelectron spectroscopy. Results show that the Fe sublayers are weakly exchange coupled for d{sub V} > 1.4 nm. Results on the coercivity studies as a function of the V interlayer thickness show near d{sub V} ∼ 1.95 nm (∼2.45 nm) weak antiferromagnetic (ferromagnetic) coupling, respectively. The hydrogenation of the Fe/V/Fe trilayers leads to increase of the strength of the ferromagnetic interlayer exchange coupling.

  10. The effect of voids on the hardening of body-centered cubic Fe

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Ryosuke, E-mail: ryosuke.nakai@jupiter.qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Yabuuchi, Kiyohiro, E-mail: k-yabuuchi@iae.kyoto-u.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Nogami, Shuhei, E-mail: shuhei.nogami@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Hasegawa, Akira, E-mail: akira.hasegawa@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan)

    2016-04-01

    The mechanical properties of metals are affected by various types of defects. Hardening is usually described through the interaction between dislocations and obstacles, in the so-called line tension theory. The strength factor in the line tension theory represents the resistance of a defect against the dislocation motion. In order to understand hardening from the viewpoint of the microstructure, an accurate determination of the strength factor of different types of defects is essential. In the present study, the strength factor of voids in body-centered cubic (BCC) Fe was investigated by two different approaches: one based on the Orowan equation to link the measured hardness with the average size and density of voids, and the other involving direct observation of the interaction between dislocations and voids by transmission electron microscope (TEM). The strength factor of voids induced by ion irradiation estimated by the Orowan equation was 0.6, whereas the strength factor estimated by the direct TEM approach was 0.8. The difference in the strength factors measured by the two approaches is due to the positional relationship between dislocations and voids: the central region of a void is stronger than the tip. Moreover, the gliding plane and the direction of dislocation may also affect the strength factor of voids. This study determined the strength factor of voids in BCC Fe accurately, and suggested that the contribution of voids to the irradiation hardening is larger than that of dislocation loops and Cu-rich precipitates. - Highlights: • The strength factor of voids in BCC Fe was experimentally investigated. • The strength factor of voids estimated by the line tension theory was 0.6. • The strength factor of voids estimated by the bowing angle of dislocations was 0.8. • The different strength factors are due to the positional relationship.

  11. PREFACE: XIV Mexican School on Particles and Fields

    Science.gov (United States)

    Bashir, Adnan; Contreras, Guillermo; Raya, Alfredo; Tejeda-Yeomans, Maria Elena

    2011-03-01

    The XIV Mexican School on Particles and Fields took place from 8-12 November, 2010, in the colonial city of Morelia, Michoacan, Mexico. The format of the school was such that the morning sessions were devoted to theoretical and experimental reviews, whereas parallel thematic sessions were held in the afternoons. All the reviews and seminars were delivered by experts of international prestige on subjects which are of current interest to the global scientific community and are also actively pursued within Mexico. In order to equip the attending graduate students and post docs with the necessary introductory tools to allow them to benefit substantially from the specialized seminars, a series of mini-courses were offered prior to the event from 4-7 November 2010, in the Auditorium of the Faculty of Science of the University of Michoacan (UMSNH). The length of each course was about 5 hours, English being the language of instruction. An informal and friendly atmosphere was encouraged during the courses so that the students could overcome their inhibitions and actively participate in the discussions. A novel feature of this event was a colloquium aimed at the general public and younger students of pre-undergraduate level, which allowed the expert scientists to reach out to a wider community and raise their awareness and interest in one of the most fascinating and vital fields of knowledge. The XIV-MSPF was organized by the Division of Particles and Fields of the Mexican Physical Society. It was generously sponsored by several institutions: Consejo Estatal de Ciencia y Tecnológico (COECyT) del Estado de Michoacán, Universidad Michoacana de San Nicolás de Hidalgo, Universidad de Sonora, Universidad Nacional Autónoma de México, Universidad de Guanajuato, Universidad de Sinaloa, Centro de Investigaciones de Estudios Avanzados del IPN (CINVESTAV), Consejo Nacional de Ciencia y Tecnología (CONACyT), la Academia Mexicana de Ciencias and, most importantly, the Red Nacional

  12. Adhesive and Cohesive Strength in FeB/Fe2B Systems

    Science.gov (United States)

    Meneses-Amador, A.; Blancas-Pérez, D.; Corpus-Mejía, R.; Rodríguez-Castro, G. A.; Martínez-Trinidad, J.; Jiménez-Tinoco, L. F.

    2018-05-01

    In this work, FeB/Fe2B systems were evaluated by the scratch test. The powder-pack boriding process was performed on the surface of AISI M2 steel. The mechanical parameters, such as yield stress and Young's modulus of the boride layer, were obtained by the instrumented indentation technique. Residual stresses produced on the boride layer were estimated by using the x-ray diffraction (XRD) technique. The scratch test was performed in order to evaluate the cohesive/adhesive strength of the FeB/Fe2B coating. In addition, a numerical evaluation of the scratch test on boride layers was performed by the finite element method. Maximum principal stresses were related to the failure mechanisms observed by the experimental scratch test. Shear stresses at the interfaces of the FeB/Fe2B/substrate system were also evaluated. Finally, the results obtained provide essential information about the effect of the layer thickness, the residual stresses, and the resilience modulus on the cohesive/adhesive strength in FeB/Fe2B systems.

  13. Protonation/reduction dynamics at the [4Fe-4S] cluster of the hydrogen-forming cofactor in [FeFe]-hydrogenases.

    Science.gov (United States)

    Senger, Moritz; Mebs, Stefan; Duan, Jifu; Shulenina, Olga; Laun, Konstantin; Kertess, Leonie; Wittkamp, Florian; Apfel, Ulf-Peter; Happe, Thomas; Winkler, Martin; Haumann, Michael; Stripp, Sven T

    2018-01-31

    The [FeFe]-hydrogenases of bacteria and algae are the most efficient hydrogen conversion catalysts in nature. Their active-site cofactor (H-cluster) comprises a [4Fe-4S] cluster linked to a unique diiron site that binds three carbon monoxide (CO) and two cyanide (CN - ) ligands. Understanding microbial hydrogen conversion requires elucidation of the interplay of proton and electron transfer events at the H-cluster. We performed real-time spectroscopy on [FeFe]-hydrogenase protein films under controlled variation of atmospheric gas composition, sample pH, and reductant concentration. Attenuated total reflection Fourier-transform infrared spectroscopy was used to monitor shifts of the CO/CN - vibrational bands in response to redox and protonation changes. Three different [FeFe]-hydrogenases and several protein and cofactor variants were compared, including element and isotopic exchange studies. A protonated equivalent (HoxH) of the oxidized state (Hox) was found, which preferentially accumulated at acidic pH and under reducing conditions. We show that the one-electron reduced state Hred' represents an intrinsically protonated species. Interestingly, the formation of HoxH and Hred' was independent of the established proton pathway to the diiron site. Quantum chemical calculations of the respective CO/CN - infrared band patterns favored a cysteine ligand of the [4Fe-4S] cluster as the protonation site in HoxH and Hred'. We propose that proton-coupled electron transfer facilitates reduction of the [4Fe-4S] cluster and prevents premature formation of a hydride at the catalytic diiron site. Our findings imply that protonation events both at the [4Fe-4S] cluster and at the diiron site of the H-cluster are important in the hydrogen conversion reaction of [FeFe]-hydrogenases.

  14. Lattice locations and properties of Fe in Co/Fe co-implanted ZnO

    DEFF Research Database (Denmark)

    Gunnlaugsson, H.P.; Johnston, K.; Mølholt, T.E.

    2012-01-01

    The lattice locations and electronic configurations of Fe in 57Co/57Fe implanted ZnO (to (5‐6) × 1014 Fe/cm−2) have been studied by 57Fe Mössbauer emission spectroscopy. The spectra acquired upon room temperature implantation show ∼20% of the probe atoms as Fe2+ on perturbed Zn sites and the rema......The lattice locations and electronic configurations of Fe in 57Co/57Fe implanted ZnO (to (5‐6) × 1014 Fe/cm−2) have been studied by 57Fe Mössbauer emission spectroscopy. The spectra acquired upon room temperature implantation show ∼20% of the probe atoms as Fe2+ on perturbed Zn sites...... and the remaining fraction as Fe2+ in damage sites of interstitial character. After annealing at 773 K, ∼20% remain on crystalline sites, while the damage fraction has partly disappeared and instead a ∼30% fraction occurs as high‐spin Fe3+, presumably in precipitates. This suggests that precipitation of Co/Fe in ZnO...... likely takes place at relatively low temperatures, thus explaining some of the discrepancies in the literature regarding magnetic properties of 3d metal‐doped ZnO....

  15. Moessbauer Study of Electrodeposited Fe/Fe-Oxide Multilayers

    International Nuclear Information System (INIS)

    Kuzmann, E.; Homonnay, Z.; Klencsar, Z.; Vertes, A.; Lakatos-Varsanyi, M.; Miko, A.; Varga, L.K.; Kalman, E.; Nagy, F.

    2005-01-01

    Iron has been deposited electrochemically by short current pulses in Na-saccharin containing FeII-chloride and sulphate solution electrolytes. Combined electrochemical techniques with initial pulse plating of iron nanolayer and its subsequent anodic oxidation under potential control have been used for production of Fe/Fe-oxide multilayers. 57Fe CEM spectra of pulse plated iron revealed the presence of a minor doublet attributed mainly to γ-FeOOH in addition to the dominant sextet of α-iron. In the case of anodically oxidized pulse plated iron and of samples after repeated deposition of anodically oxidized pulse plated iron an additional minor doublet, assigned to ferrous chloride, also appears in the Moessbauer spectra. A significant change in the magnetic anisotropy of α-iron was observed with the anodic oxidation. The thickness of the layers were estimated from the CEM spectrum data by a modified computer program of the Liljequist method. The coercive field and the power loss versus frequency data showed that the pulse plated iron cores are good inductive elements up to several kHz frequencies

  16. Colorimetric determination of Fe2+/Fe3+ ratio in radioactive glasses

    International Nuclear Information System (INIS)

    Coleman, C.J.; Baumann, E.W.; Bibler, N.E.

    1992-01-01

    In the vitrification of nuclear wastes, the Fe 2+ /Fe 3+ ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe 2+ /Fe 3+ ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that will be produced in the Savannah River Site Defense Waste Processing Facility. The first step of the method is dissolution of finely crushed glass with a hydrofluoric/sulfuric acid mixture with ammonium vanadate added to preserve the Fe 2+ content of the glass during the dissolution. Boric acid is then added to complex fluoride and to destroy iron-fluoride complexes. After adjusting the solution to pH 5, FerroZine TM (trademark of the Hach Company, Loveland, CO) reagent is added to form a magenta-colored complex with Fe 2+ . The absorbance at 562 nm is measured by using a fiber optic-coupled photodiode array spectrophotometer. Ascorbic acid is then used to reduce all the iron in solution to Fe 2+ and the absorbance is again measured. The difference in absorbance measurements corresponds to the Fe 3+ in the sample and the Fe 2+ /Fe 3+ ratio can be calculated

  17. Behaviour of Fe4O5-Mg2Fe2O5 solid solutions and their relation to coexisting Mg-Fe silicates and oxide phases

    Science.gov (United States)

    Uenver-Thiele, Laura; Woodland, Alan B.; Miyajima, Nobuyoshi; Ballaran, Tiziana Boffa; Frost, Daniel J.

    2018-03-01

    Experiments at high pressures and temperatures were carried out (1) to investigate the crystal-chemical behaviour of Fe4O5-Mg2Fe2O5 solid solutions and (2) to explore the phase relations involving (Mg,Fe)2Fe2O5 (denoted as O5-phase) and Mg-Fe silicates. Multi-anvil experiments were performed at 11-20 GPa and 1100-1600 °C using different starting compositions including two that were Si-bearing. In Si-free experiments the O5-phase coexists with Fe2O3, hp-(Mg,Fe)Fe2O4, (Mg,Fe)3Fe4O9 or an unquenchable phase of different stoichiometry. Si-bearing experiments yielded phase assemblages consisting of the O5-phase together with olivine, wadsleyite or ringwoodite, majoritic garnet or Fe3+-bearing phase B. However, (Mg,Fe)2Fe2O5 does not incorporate Si. Electron microprobe analyses revealed that phase B incorporates significant amounts of Fe2+ and Fe3+ (at least 1.0 cations Fe per formula unit). Fe-L2,3-edge energy-loss near-edge structure spectra confirm the presence of ferric iron [Fe3+/Fetot = 0.41(4)] and indicate substitution according to the following charge-balanced exchange: [4]Si4+ + [6]Mg2+ = 2Fe3+. The ability to accommodate Fe2+ and Fe3+ makes this potential "water-storing" mineral interesting since such substitutions should enlarge its stability field. The thermodynamic properties of Mg2Fe2O5 have been refined, yielding H°1bar,298 = - 1981.5 kJ mol- 1. Solid solution is complete across the Fe4O5-Mg2Fe2O5 binary. Molar volume decreases essentially linearly with increasing Mg content, consistent with ideal mixing behaviour. The partitioning of Mg and Fe2+ with silicates indicates that (Mg,Fe)2Fe2O5 has a strong preference for Fe2+. Modelling of partitioning with olivine is consistent with the O5-phase exhibiting ideal mixing behaviour. Mg-Fe2+ partitioning between (Mg,Fe)2Fe2O5 and ringwoodite or wadsleyite is influenced by the presence of Fe3+ and OH incorporation in the silicate phases.

  18. Giant Faraday Rotation through Ultrasmall Fe0 n Clusters in Superparamagnetic FeO-SiO2 Vitreous Films.

    Science.gov (United States)

    Nakatsuka, Yuko; Pollok, Kilian; Wieduwilt, Torsten; Langenhorst, Falko; Schmidt, Markus A; Fujita, Koji; Murai, Shunsuke; Tanaka, Katsuhisa; Wondraczek, Lothar

    2017-04-01

    Magnetooptical (MO) glasses and, in particular, Faraday rotators are becoming key components in lasers and optical information processing, light switching, coding, filtering, and sensing. The common design of such Faraday rotator materials follows a simple path: high Faraday rotation is achieved by maximizing the concentration of paramagnetic ion species in a given matrix material. However, this approach has reached its limits in terms of MO performance; hence, glass-based materials can presently not be used efficiently in thin film MO applications. Here, a novel strategy which overcomes this limitation is demonstrated. Using vitreous films of x FeO·(100 - x )SiO 2 , unusually large Faraday rotation has been obtained, beating the performance of any other glassy material by up to two orders of magnitude. It is shown that this is due to the incorporation of small, ferromagnetic clusters of atomic iron which are generated in line during laser deposition and rapid condensation of the thin film, generating superparamagnetism. The size of these clusters underbids the present record of metallic Fe incorporation and experimental verification in glass matrices.

  19. 57Fe Moessbauer and magnetic studies of ErFe12-xNbx

    International Nuclear Information System (INIS)

    Wang, J L; Campbell, S J; Cadogan, J M; Tegus, O; Edge, A V J

    2005-01-01

    The structural and magnetic properties of ErFe 12-x Nb x compounds (x 0.6, 0.7 and 0.8) have been investigated by x-ray diffraction, ac susceptibility and dc magnetization measurements and 57 Fe Moessbauer spectroscopy. Refinements of the x-ray diffraction patterns show that the Nb atoms preferentially occupy the 8i sites; this can be understood in the terms of enthalpy effects and differences in the metallic radii. The average Fe-Fe distance at the different sites is found to behave as d Fe-Fe (8i)> d Fe-Fe (8j)> d Fe-Fe (8f). The unit cell volume increases slightly with increasing Nb content, consistent with the larger radius of Nb compared with Fe. A spin reorientation from easy-axis at room temperature to easy-cone at low temperatures has been detected for all compounds. The spin reorientation temperatures T sr in ErFe 12-x Nb x compounds remain essentially unchanged (T sr ∼42-44 K) with increasing Nb concentration, whereas a significant decrease in T sr (T sr1 ∼236-204 K; T sr2 ∼154-94 K) is obtained in DyFe 12-x Nb x from x = 0.6 to 0.8. This can be understood by taking the different crystal-field terms responsible for the spin reorientation in the two systems into account. We find that the spin-reorientation process is particularly sensitive to the sixth-order term B 60 O 60 of the crystal field acting on the Er 3+ ion, due to its large and positive value of γ J . 57 Fe hyperfine interaction parameters and magnetic moments values have been determined for the 8i, 8j and 8f sites from the Moessbauer spectra. The weighted average 57 Fe hyperfine field values were found to follow a T 2 dependence; this suggests that a single-particle excitation mechanism is responsible for reduction of the 3d-sublattice magnetization with increasing temperature

  20. Hyperfine fields of Fe in Nd2Fe14BandSm2Fe17N3

    Science.gov (United States)

    Akai, Hisazumi; Ogura, Masako

    2015-03-01

    High saturation magnetization of rare-earth magnets originates from Fe and the strong magnetic anisotropy stems from f-states of rare-earth elements such as Nd and Sm. Therefore the hyperfine fields of both Fe and rare-earth provide us with important pieces of information: Fe NMR enable us to detect site dependence of the local magnetic moment and magnetic anisotropy (Fe sites also contribute to the magnetic anisotropy) while rare-earth NQR directly give the information of electric field gradients (EFG) that are related to the shape of the f-electron cloud as well as the EFG produced by ligands. In this study we focus on the hyperfine fields of materials used as permanent magnets, Nd2Fe14BandSm2Fe17N3 from theoretical points of view. The detailed electronic structure together with the hyperfine interactions are discussed on the basis of the first-principles calculation. In particular, the relations between the observed hyperfine fields and the magnetic properties are studies in detail. The effects of doping of those materials by other elements such as Dy and the effects of N adding in Sm2Fe17N3 will be discussed. This work was supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

  1. Imaging and spectroscopic observations of the 9 March 2016 Total Solar Eclipse in Palangkaraya

    International Nuclear Information System (INIS)

    Kholish, Abdul Majid Al; Jihad, Imanul; Andika, Irham Taufik; Puspitaningrum, Evaria; Ainy, Fathin Q.; Ramadhan, Sahlan; Arifyanto, M. Ikbal; Malasan, Hakim L.

    2016-01-01

    The March 9 th 2016 total solar eclipse observation was carried out at Universitas Palangkaraya, Central Kalimantan. Time-resolved imaging of the Sun has been conducted before, after, and during totality of eclipse while optical spectroscopic observation has been carried out only at the totality. The imaging observation in white light was done to take high resolution images of solar corona. The images were taken with a DSLR camera that is attached to a refractor telescope (d=66 mm, f/5.9). Despite cloudy weather during the eclipse moments, we managed to obtain the images with lower signal-to-noise ratio, including identifiable diamond ring, prominence and coronal structure. The images were processed using standard reduction procedure to increase the signal-to-noise ratio and to enhance the corona. Then, the coronal structure is determined and compared with ultraviolet data from SOHO to analyze the correlation between visual and ultraviolet corona. The spectroscopic observation was conducted using a slit-less spectrograph and a DSLR camera to obtain solar flash spectra. The flash spectra taken during the eclipse show emissions of H 4861 Å, He I 5876 Å, and H 6563 Å. The Fe XIV 5303 Å and Fe X 6374 Å lines are hardly detected due to low signal-to-noise ratio. Spectral reduction and analysis are conducted to derive the emission lines intensity relative to continuum intensity. We use the measured parameters to determine the temperature of solar chromosphere. (paper)

  2. Ferromagnetic resonance on oxideless magnetic Fe and FeRh nanoparticles; Ferromagnetische Resonanz an oxidfreien magnetischen Fe und FeRh Nanopartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Trunova, Anastasia

    2009-05-25

    This work is dedicated to investigations of structural and magnetic properties of the colloidal Fe/Fe{sub x}O{sub y} nanocubes (13 nm) and the Fe{sub x}Rh{sub 100-x} core/shell nanoparticles (2 nm). As compared with other works, where the measurements on oxidized nanoparticles were carried out, we additionally performed investigations on nanoparticles in an oxide free state. In order to make the measurements on oxide free particles possible, oxygen- and hydrogenplasma was used to remove the ligands and reduce the oxide shell of the Fe nanocubes. The oxide free Fe nanocubes were covered with a Ag/Pt protective coating to prevent them from new oxidation. This method allowed carrying out the magnetic measurements on oxide free Fe nanocubes. Micromagnetic simulations as well as simulations of the high frequency susceptibility were used for the data analysing. It was found that both the g-factor g=2.09{+-}0.01 and the anisotropy constant K{sub 4}=(4.8{+-}0.5).10{sup 4} J/m{sup 3} coincide with that of bulk iron. However, the saturation magnetization M{sub S}(5 K)=(1.2{+-}0.12).10{sup 6} A/m differs from the bulk value by 30%. The reduction by 30% compared to the bulk value in the case of nanoparticles may be caused by the following possible reasons: a) the presence of inner oxide layer (approx. 10 at.%) that cannot be reduced; b) the anti-parallel order between magnetic moments of iron core and magnetic moments of antiferomagnetic iron oxide; c) some structural changes of the surface after plasma treatment. The obtained damping parameter {alpha}=0.03{+-}0.005 is ten times larger than that of the Fe layers as it is known for nanoparticles systems in general. The core/shell Fe{sub x}Rh{sub 100-x} nanoparticles (x=80,50) were produced under Ar-atmosphere and were sealed into a quartz tube to prevent oxidation. The analysis of g-factors shows that the value for the FePh nanoparticles with Fe-rich core is larger (g=2.08{+-}0.01) than that for the nanoparticles with Rh

  3. Infrared spectroscopic study of CaFe0.7Co0.3O3

    Science.gov (United States)

    Zhang, C. X.; Xia, H. L.; Dai, Y. M.; Qiu, Z. Y.; Sui, Q. T.; Long, Y. W.; Qiu, X. G.

    2017-08-01

    Temperature-dependent infrared spectroscopy has been investigated for CaFe0.7Co0.3O3 which undergoes a ferromagnetic transition at TC≈177 K . It is observed that the spectral weight is transferred from ˜4800 -14 000 cm-1 to ˜0 -4800 cm-1 as the temperature is lowered around TC. Such a large-range spectral weight transfer is attributed to the Hund's interaction. The phonons in CaFe0.7Co0.3O3 show minor asymmetric line shapes, implying relatively weak electron-phonon coupling compared with the parent compound CaFeO3. The optical conductivity also reveals a broad peak structure in the range of ˜700 -1500 cm-1. Fit by the model of single-polaron absorption, the broad peak is interpreted by the excitation of polarons. From the fitting parameters of the polaron peak, we estimate the electron-phonon coupling constant α ˜ 0.4 -0.5 , implying that CaFe0.7Co0.3O3 falls into the weak-coupling regime.

  4. Neutron capture resonances in 56Fe and 58Fe in the energy range from 10 to 100 keV

    International Nuclear Information System (INIS)

    Kaeppeler, F.; Wisshak, K.; Hong, L.D.

    1982-11-01

    The neutron capture cross section of 56 Fe and 58 Fe has been measured in the energy range from 10 to 250 keV relative to the gold standard. A pulsed 3 MV Van de Graaff accelerator and the 7 Li(p, n) reaction served as a neutron source. Capture gamma rays were detected by two C 6 D 6 detectors, which were operated in coincidence and anticoincidence mode. Two-dimensional data acquisition allowed to apply the pulse height weighting technique off-line. The samples were located at a flight path of 60 cm. The total time resolution was 1.2 ns thus allowing for an energy resolution of 2 ns/m. The experimental set-up was optimized with respect to low background and low neutron sensitivity. The additional flight path of 4 cm from the sample to the detector was sufficient to discriminate capture of sample scattered neutrons by the additional time of flight. In this way reliable results were obtained even for the strong s-wave resonances of both isotopes. The experimental capture yield was analyzed with the FANAC code. The energy resolution allowed to extract resonance parameters in the energy range from 10 to 100 keV. The individual systematic uncertainties of the experimental method are discussed in detail. They were found to range between 5 and 10% while the statistical uncertainty is 3-5% for most of the resonances. A comparison to the results of other authors exhibits in case of 56 Fe systematic differences of 7-11%. For 58 Fe the present results differ up to 50% from the only other measurement for this isotope. (orig.) [de

  5. Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

    2017-05-15

    Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.

  6. La couleur à Lille au xviie siècle, de Philippe IV à Louis XIV The colour of Lille in the seventeenth century, from Philippe IV to Louis XIV

    Directory of Open Access Journals (Sweden)

    Étienne Poncelet

    2007-06-01

    Full Text Available Pays polychrome, de pierres blanches ou bleues et de briques roses, jaunes ou noires, la Flandre manie depuis le Moyen Âge les jeux colorés de matériaux. Sa capitale wallonne, Lille, est la ville méridionale des Pays‑Bas catholiques où s’acclimatent les plantes de la compagnie des Indes néerlandaises et où se déroulent les « joyeuses entrées » des comtes, ducs de Bourgogne, archiducs et autres rois d’Espagne. Cette tradition de luxuriance se traduit à l’âge d'or bourguignon par une efflorescence de couleurs sur les édifices qui durera jusqu’à la prise de Lille par Louis XIV en 1667. Les portes « espagnoles » affichent leurs briques émaillées de couleur. L’hospice Comtesse placarde son retable de pierres peintes sur sa façade d’entrée. La Vieille Bourse colore ses façades au modèle d’un cabinet d’ébénisterie avec ses incrustations de pierres nacrées et de brique luisantes comme les écailles de tortue. Le style franco‑lillois transmettra ce goût pour la couleur à travers la reconstitution du centre ville au xviie siècle, ce dont témoigne le plan-relief de 1743. Les restaurations depuis une dizaine d’années retrouvent cette tradition de joie urbaine dans les autres « grand-places » des villes du Nord.A polychromatic land of white and blue stone and pink, yellow and black brick, Flanders has sought colour combinations in building materials since the Middle Ages. Its French-speaking capital, Lille, was the city in the south of the Catholic Netherlands where plants imported by the Dutch East Indies Company acclimatized and where the ‘Joyous Entry’ celebrations of the counts, Dukes of Burgundy, archdukes and kings of Spain took place. During the golden age of Burgundy, this tradition of luxuriance was reflected in the increasing use of colours on buildings, a trend that would endure until the siege of Lille by Louis XIV in 1667. The ‘Spanish’ gates display brickwork enamelled in

  7. Fe2O3/Reduced Graphene Oxide/Fe3O4 Composite in Situ Grown on Fe Foil for High-Performance Supercapacitors.

    Science.gov (United States)

    Zhao, Chongjun; Shao, Xiaoxiao; Zhang, Yuxiao; Qian, Xiuzhen

    2016-11-09

    A Fe 2 O 3 /reduced graphene oxide (RGO)/Fe 3 O 4 nanocomposite in situ grown on Fe foil was synthesized via a simple one-step hydrothermal growth process, where the iron foil served as support, reductant of graphene oxide, Fe source of Fe 3 O 4 , and also the current collector of the electrode. When it directly acted as the electrode of a supercapacitor, as-synthesized Fe 2 O 3 /RGO/Fe 3 O 4 @Fe exhibited excellent electrochemical performance with a high capability of 337.5 mF/cm 2 at 20 mA/cm 2 and a superior cyclability with 2.3% capacity loss from the 600th to the 2000th cycle.

  8. Ferromagnetic resonance study of sputtered NiFe/V/NiFe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Alayo, W., E-mail: willian.rodriguez@ufpel.edu.br [Departamento de Física – IFM, Universidade Federal de Pelotas, 96010-900 Rio Grande do Sul (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, RJ, 22290-180 (Brazil)

    2015-03-01

    The Ni{sub 81}Fe{sub 19}/V/Ni{sub 81}Fe{sub 19} heterostructures has been produced by magnetron sputtering and analyzed by ferromagnetic resonance. Two systems were investigated: the non symmetrical NiFe(50 Å)/V(t)/NiFe(30 Å) trilayers and the symmetrical NiFe(80 Å)/V(t)/NiFe(80 Å) trilayers, with variable ultrathin V thickness t. Ferromagnetic exchange coupling was evidenced for t below 10 Å by the excitation of the optic mode, in the case of the non symmetrical samples, and by the observation of a single resonance mode for the symmetrical trilayers. For larger V thickness, all samples exhibited two modes, which were attributed to the resonance of the individual NiFe layers with different effective magnetizations. The analysis with the equilibrium and resonance conditions provided the exchange coupling constants and effective magnetizations. - Highlights: • We present a study of symmetrical and non symmetrical NiFe/V/NiFe trilayers deposited on Si single crystals by ferromagnetic resonance (FMR) at room temperature. • For the non symmetrical trilayers, the FMR spectra show the optic and acoustic modes for samples with very thin V layer thicknesses, evidencing ferromagnetic exchange coupling, whereas, for larger V thickness, the spectra exhibited two well resolved modes associated to each independent NiFe layer. For the symmetrical trilayers, strong ferromagnetic exchange coupling is evidenced by the observation of a single resonance mode. • The analysis with the equilibrium condition and dispersion relation provides the exchange coupling constants and effective magnetizations.

  9. Fe-Vacancy-Induced Ferromagnetism in Tetragonal FeSe Thin Films

    International Nuclear Information System (INIS)

    Yong-Feng, Li; Gui-Bin, Liu; Li-Jie, Shi; Bang-Gui, Liu

    2009-01-01

    Motivated by recent experiments, we investigate structural, electronic, and magnetic properties of tetragonal FeSe with Fe vacancies using the state-of-the-art first-principles method. We show that Fe vacancies tend to stay in the same one of the two sublattices and thus induce ferromagnetism in the ground-state phase. Our calculated net moment is in good agreement with the experimental data available. Therefore, the ferromagnetism observed in tetragonal FeSe thin films is explained. It could be made controllable soon for spintronic applications

  10. Mössbauer Studies of Core-Shell FeO/Fe3O4 Nanoparticles

    Science.gov (United States)

    Kamzin, A. S.; Valiullin, A. A.; Khurshid, H.; Nemati, Z.; Srikanth, H.; Phan, M. H.

    2018-02-01

    FeO/Fe3O4 nanoparticles were synthesized by thermal decomposition. Electron microscopy revealed that these nanoparticles were of the core-shell type and had a spherical shape with an average size of 20 nm. It was found that the obtained FeO/Fe3O4 nanoparticles had exchange coupling. The effect of anisotropy on the efficiency of heating (hyperthermic effect) of FeO/Fe3O4 nanoparticles by an external alternating magnetic field was examined. The specific absorption rate (SAR) of the studied nanoparticles was 135 W/g in the experiment with an external alternating magnetic field with a strength of 600 Oe and a frequency of 310 kHz. These data led to an important insight: the saturation magnetization is not the only factor governing the SAR, and the efficiency of heating of magnetic FeO/Fe3O4 nanoparticles may be increased by enhancing the effective anisotropy. Mössbauer spectroscopy of the phase composition of the synthesized nanoparticles clearly revealed the simultaneous presence of three phases: magnetite Fe3O4, maghemite γ-Fe2O3, and wustite FeO.

  11. Neutron irradiation effects in Fe and Fe-Cr at 300 °C

    International Nuclear Information System (INIS)

    Chen, Wei-Ying; Miao, Yinbin; Gan, Jian; Okuniewski, Maria A.; Maloy, Stuart A.; Stubbins, James F.

    2016-01-01

    Fe and Fe-Cr (Cr = 10–16 at.%) specimens were neutron-irradiated at 300 °C to 0.01, 0.1 and 1 dpa. The TEM observations indicated that the Cr significantly reduced the mobility of dislocation loops and suppressed vacancy clustering, leading to distinct damage microstructures between Fe and Fe-Cr. Irradiation-induced dislocation loops in Fe were heterogeneously observed in the vicinity of grown-in dislocations, whereas the loop distribution observed in Fe-Cr is much more uniform. Voids were observed in the irradiated Fe samples, but not in irradiated Fe-Cr samples. Increasing Cr content in Fe-Cr results in a higher density, and a smaller size of irradiation-induced dislocation loops. Orowan mechanism was used to correlate the observed microstructure and hardening, which showed that the hardening in Fe-Cr can be attributed to the formation of dislocation loops and α′ precipitates. -- Graphical abstract: Addition of Cr in Fe suppressed the mobility of mobile 1/2<111> dislocation loops and increased the proportion of immobile <100> dislocation loops, leading to a transition of loop distribution from highly heterogeneous to uniform. Display Omitted

  12. Non-conventional ordering studied by magnetic resonance in Fe-doped manganites

    International Nuclear Information System (INIS)

    Gutierrez, J.; Siruguri, V.; Barandiaran, J.M.; Pena, A.; Lezama, L.; Rojo, T.

    2006-01-01

    Coexistence of ferromagnetic (FM) and paramagnetic (PM) phases in La 0.7 Pb 0.3 (Mn 1-x Fe x )O 3 (0.1=< x=<0.3) manganites is studied by the electron spin resonance (ESR) technique. Doping with Fe gives rise to a progressive decrease both in the low-temperature magnetic moment and magnetic order temperature values. Obtained spectra show narrow resonance signals above Curie temperature that transform to asymmetric Dyson-like signals as temperature decreases. The evolution of line width with temperature shows minima that correlate directly with the obtained paramagnetic Curie temperatures. Analysis of spectra above and below magnetic order temperatures reveals features of complex PM to FM transitions and coexistence of both type of phases in a wide range of temperatures

  13. Fe-N and (Fe, Ni)-N Fine Powders for Magnetic Recording

    International Nuclear Information System (INIS)

    Chen Ziyu; Li Fashen

    1998-01-01

    Combining Moessbauer spectroscopy with magnetic property measurement, we have studied Fe-N and (Fe, Ni)-N powders for magnetic recording. The typical particles of the core (α-Fe)/shell (γ'-Fe 4 N) structure have been successfully prepared. All the products are stabilized in a multi-organic solution. It has been found that the coercivity can be changed from 300 to 800 Oe by adjusting the shape of the particles. The special saturation magnetization of the particles can be adjusted from 120 to 180emu/g and their chemical stability is improved by substituting nickel for iron in γ'-Fe 4 N. Following experiments for corrosion resistance, it is expected that (Fe, Ni)-N and the core/shell particles will be applied as recording media in the near future

  14. Fe-N and (Fe, Ni)-N Fine Powders for Magnetic Recording

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ziyu; Li Fashen [Lanzhou University, Department of Physics (China)

    1998-12-15

    Combining Moessbauer spectroscopy with magnetic property measurement, we have studied Fe-N and (Fe, Ni)-N powders for magnetic recording. The typical particles of the core ({alpha}-Fe)/shell ({gamma}'-Fe{sub 4}N) structure have been successfully prepared. All the products are stabilized in a multi-organic solution. It has been found that the coercivity can be changed from 300 to 800 Oe by adjusting the shape of the particles. The special saturation magnetization of the particles can be adjusted from 120 to 180emu/g and their chemical stability is improved by substituting nickel for iron in {gamma}'-Fe{sub 4}N. Following experiments for corrosion resistance, it is expected that (Fe, Ni)-N and the core/shell particles will be applied as recording media in the near future.

  15. Structural, electronic and magnetic properties of partially inverse spinel CoFe2O4: a first-principles study

    International Nuclear Information System (INIS)

    Hou, Y H; Liu, Z W; Yu, H Y; Zhong, X C; Qiu, W Q; Zeng, D C; Wen, L S; Zhao, Y J

    2010-01-01

    Partially inverse spinel CoFe 2 O 4 , which may be prepared through various heat treatments, differs remarkably from the ideal inverse spinel in many properties. The structure of partially inverse spinel CoFe 2 O 4 as well as its electronic and magnetic properties through a systemic theoretical calculation of (Co 1-x Fe x ) Tet (Co x Fe 2-x ) Oct O 4 (x = 0, 0.25, 0.5, 0.75 and 1.0) have been investigated by the generalized gradient approximation (GGA) + U approach. It is found that the Co and Fe ions prefer their high spin configurations with higher spin moments at octahedral sites in all the studied cases, in line with experimental observations. The Co ions at the octahedral sites favour being far away from each other in the partial inverse spinels, which also show half metallicity at certain inversion degrees.

  16. Exchange biased FeNi/FeMn bilayers with coercivity and switching field enhanced by FeMn surface oxidation

    Directory of Open Access Journals (Sweden)

    A. V. Svalov

    2013-09-01

    Full Text Available FeNi/FeMn bilayers were grown in a magnetic field and subjected to heat treatments at temperatures of 50 to 350 °C in vacuum or in a gas mixture containing oxygen. In the as-deposited state, the hysteresis loop of 30 nm FeNi layer was shifted. Low temperature annealing leads to a decrease of the exchange bias field. Heat treatments at higher temperatures in gas mixture result in partial oxidation of 20 nm thick FeMn layer leading to a nonlinear dependence of coercivity and a switching field of FeNi layer on annealing temperature. The maximum of coercivity and switching field were observed after annealing at 300 °C.

  17. The lowest 5g-6h supermultiplet of Fe II

    International Nuclear Information System (INIS)

    Biemont, E.; Palmeri, P.

    1997-01-01

    The 3d 6 ( 5 D)6h subconfiguration of Fe II is established by means of 74 newly identified 5g-6h transitions. These lines are observed in a Fourier-transform spectrum of iron emitted from a hollow-cathode discharge in the region 5350-5410 cm -1 . The application of the ''quadrupolic'' approximation shows that the JK coupling is well represented in the 3d 6 6h configuration. The identification of the lines in the spectra was facilitated by the comparison of the observed intensities with oscillator strengths calculated in the framework of the relativistic Hartree-Fock (HFR) approximation and also by consideration of the full width at half maximum (FWHM) of the profiles. (orig.)

  18. Spin-dependent electronic transport characteristics in Fe4N/BiFeO3/Fe4N perpendicular magnetic tunnel junctions

    Science.gov (United States)

    Yin, Li; Wang, Xiaocha; Mi, Wenbo

    2018-01-01

    Perpendicular magnetic tunnel junctions (MTJs) have attracted increasing attention owing to the low energy consumption and wide application prospects. Herewith, against Julliere's formula, an inverse tunnel magnetoresistance (TMR) appears in tetragonal Fe4N/BiFeO3/Fe4N perpendicular MTJs, which is attributed to the binding between the interface resonant tunneling state and central (bordered) hot spots. Especially, antiferromagnetic BiFeO3 shows an extra spin-polarized resonant state in the barrier, which provides a magnetic-barrier factor to affect the tunneling transport in MTJs. Meanwhile, due to the spin-polarized transport in Fe4N/BiFeO3/Fe4N MTJs, the sign of TMR can be tuned by the applied bias. The tunable TMR and resonant magnetic barrier effect pave the way for clarifying the tunneling transport in other junctions and spintronic devices.

  19. Dust Destruction in the Supernova Remnant N49: Additional WiFeS Integral Field data AnalysisRachel Quigley, Rachael Huxford, Parviz Ghavamian, Mike Dopita

    Science.gov (United States)

    Quigley, Rachel; Ghavamian, Parviz

    2018-01-01

    Abstract:The supernova remnant N49, located in the Large Magellanic Cloud (LMC), is widely researched because of its relatively young age and its location near a dense, dusty molecular cloud in the interstellar medium (ISM). N49 has entered into its radiative phase more quickly than to be expected for the age of this remnant. As a consequence, N49 is showing signs that the diffuse hot interior is starting to cool and recombine. Using existing integral field spectra of SNR N49, different Fe emission lines and other spectral lines were extracted via python tools, following a similar approach to Dopita et al. (2016). At optical wavelengths, the dependence of [OIII]5007/4363 ratio on shock velocity is evident. This diagnostic is important because the [OIII]-emitting zone in low-velocity shocks of the cooling post-shock gas is hot. As the shock velocity increases, the temperature indicated by the [OIII] parameter falls. The dependence of Fe depletion lines on shock velocity is rather weak. Using [FeIII]:[OIII] diagnostic, the properties of dust destruction and production of dust in the SNR can be determined. Using this method, line ratios for other emission lines can be compared to the MAPPINGS predictions of Allen et al. (2008) to study the range of shock speeds present in the supernova remnant, where radiative shocks are driven into interstellar gas.

  20. Effect of Fe-Mn addition on microstructure and magnetic properties of NdFeB magnetic powders

    Science.gov (United States)

    Kurniawan, C.; Purba, A. S.; Setiadi, E. A.; Simbolon, S.; Warman, A.; Sebayang, P.

    2018-03-01

    In this paper, the effect of Fe-Mn alloy addition on microstructures and magnetic properties of NdFeB magnetic powders was investigated. Varied Fe-Mn compositions of 1, 5, and 10 wt% were mixed with commercial NdFeB type MQA powders for 15 minutes using shaker mill. The characterizations were performed by powder density, PSA, XRD, SEM, and VSM. The Fe-Mn addition increased the powder density of NdFeB/Fe-Mn powders. On the other side, particle size distribution slightly decreased as the Fe-Mn composition increases. Magnetic properties of NdFeB/Fe-Mn powders changed with the increasing of Fe-Mn content. SEM analysis showed the particle size of NdFeB/Fe-Mn powder was smaller as the Fe-Mn composition increases. It showed that NdFeB/Fe-Mn particles have different size and shape for NdFeB and Fe-Mn particles separately. The optimum magnetic properties of NdFeB/Fe-Mn powder was achieved on the 5 wt% Fe-Mn composition with remanence M r = 49.45 emu/g, coercivity H c = 2.201 kOe, and energy product, BH max = 2.15 MGOe.

  1. Preliminary design of bellows for the DNB beam source by EJMA and FE linear analysis

    International Nuclear Information System (INIS)

    Trapasiya, Shobhit; Muvvala, Venkata Nagaraju; Rambilas, P.; Gangadharan, Roopesh; Rotti, Chandramouli; Chakraborty, Arun Kumar; Sharma, Dheeraj Kumar

    2015-01-01

    In piping system, U-shaped Bellows are widely used among flexible elements. In general, bellows are typically design for Fatigue behavior according to the EJMA standard based on empirically generated fatigue curves. The present work proposes a methodology in the design of bellows by design by analyses and validates its design by EJMA standard. A linear FE approach is chosen to in line with the EJMA standard. The proposed methodology is benchmarked with the available literatures. The same practice is implemented in the preliminary design of a U-shaped bellows in the water line circuits of DNB beam source. DNB Beam Source is a negative ion source-based neutral beam generator for ITER operates at 100KV. The beam divergence (intrinsic) and magnetic fields from ITER torus causes deflection of beams. This calls for beam optic alignment, which are assured by BS Movement mechanism system. To accomplish the above movement requirements, bellows, which is a stringent of its kind (± 22 mm axial, ± 45 mm lateral within 400mm available space with single ply), is designed between the beam source and possible rigid interface-cooling lines coming from HVB. The paper describes right from conceptual stage to preliminary design. Optimization tools are adopted in the selecting bellow dimensions using MATLAB. At the end a coordinated approach between FE based assessment (in ANSYS) and widely applied code, EJMA is implemented for the validation of design and found FE approach is a very conservative than later in the present case. (author)

  2. Ab initio calculations of the Fe(II) and Fe(III) isotopic effects in citrates, nicotianamine, and phytosiderophore, and new Fe isotopic measurements in higher plants

    Science.gov (United States)

    Moynier, Frédéric; Fujii, Toshiyuki; Wang, Kun; Foriel, Julien

    2013-05-01

    Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ˜3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ˜1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem.

  3. Effects of metal ions on the reactivity and corrosion electrochemistry of Fe/FeS nanoparticles.

    Science.gov (United States)

    Kim, Eun-Ju; Kim, Jae-Hwan; Chang, Yoon-Seok; Turcio-Ortega, David; Tratnyek, Paul G

    2014-04-01

    Nano-zerovalent iron (nZVI) formed under sulfidic conditions results in a biphasic material (Fe/FeS) that reduces trichloroethene (TCE) more rapidly than nZVI associated only with iron oxides (Fe/FeO). Exposing Fe/FeS to dissolved metals (Pd(2+), Cu(2+), Ni(2+), Co(2+), and Mn(2+)) results in their sequestration by coprecipitation as dopants into FeS and FeO and/or by electroless precipitation as zerovalent metals that are hydrogenation catalysts. Using TCE reduction rates to probe the effect of metal amendments on the reactivity of Fe/FeS, it was found that Mn(2+) and Cu(2+) decreased TCE reduction rates, while Pd(2+), Co(2+), and Ni(2+) increased them. Electrochemical characterization of metal-amended Fe/FeS showed that aging caused passivation by growth of FeO and FeS phases and poisoning of catalytic metal deposits by sulfide. Correlation of rate constants for TCE reduction (kobs) with electrochemical parameters (corrosion potentials and currents, Tafel slopes, and polarization resistance) and descriptors of hydrogen activation by metals (exchange current density for hydrogen reduction and enthalpy of solution into metals) showed the controlling process changed with aging. For fresh Fe/FeS, kobs was best described by the exchange current density for activation of hydrogen, whereas kobs for aged Fe/FeS correlated with electrochemical descriptors of electron transfer.

  4. Dark Energy and Dark Matter Models

    OpenAIRE

    Sidharth, Burra G.

    2013-01-01

    Comment: 37 pages, latex, New Advances in Physic (91), 2013. arXiv admin note: substantial text overlap with arXiv:physics/0411224, arXiv:1011.4575, arXiv:physics/0609254, arXiv:1112.1773, arXiv:0803.4302, arXiv:0902.3342, arXiv:1201.0915, arXiv:physics/0608222, arXiv:physics/0403034, arXiv:physics/0404024, arXiv:0905.3896, arXiv:physics/0110040

  5. Influence of Ti in the β-Zr(Fe) phase stability at ambient temperature

    International Nuclear Information System (INIS)

    Coelho, J.S.

    1980-12-01

    Investigations of the Fe-Ti-Zr alloy system with concentrations ranging from 1 at.% Ti to 20 at.% Ti and with a fixed concentration of 4 at.% Fe were performed using X-Ray diffraction, Mossbauer Spectroscopy and Optical and Electronic Metallographies. The alloys were melted in arc furnace in argon atmosphere and after being homogenized, they were quenched from the beta field into cold water in order to retain the high temperature β-Zr(Fe)-Ti phase. The obtained results show that the beta phase was partially retained until the concentration of 7 at.% Ti and was completely retained at the concentration equal to or higher than 8 at.% Ti. It is assumed in Moessbauer Spectroscopy a doublet for the beta phase and a singlet for the supersatured α'-Zr(Fe)-Ti phase resulting from the martensitic transformation. The relative amount of each phase detected by Moessbauer Spectroscopy was measured by the relative area of the each spectral line. The stability of the beta phase at room temperature was discussed in terms of short-range ordering caused by the Fe-Ti bonds. Some related properties were discussed through the changing of the lattice parameter, isomer shift and quadrupole splitting. (Author) [pt

  6. Asymmetric interfaces in Fe/Ag and Ag/Fe bilayers prepared by molecular beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Tunyogi, A. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)]. E-mail: tunyogi@rmki.kfki.hu; Paszti, F. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Osvath, Z. [MTA Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest (Hungary); Tancziko, F. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Major, M. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary); Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)

    2006-08-15

    Single layers of Fe and Ag, as well as Fe/Ag (iron deposited first) and Ag/Fe bilayers were prepared by molecular beam evaporation onto Si. The samples were investigated with backscattering spectrometry (BS) and atomic force microscopy (AFM). BS spectra of Fe/Ag and Ag/Fe indicate a significant difference at the interface. In the case of Fe/Ag the Ag peak has a long tail at the interface, while for Ag/Fe the interface is abrupt. The tail in the Fe/Ag spectrum is too large to be caused by double or plural scattering. According to AFM, the effect of surface roughness is also negligible. In spite of the fact that Fe and Ag are completely immiscible in equilibrium, this tail, however, suggests that some Ag is located in the Fe layer. After annealing, both samples show mixing between the two layers; this is much larger again for Fe/Ag.

  7. Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2006-01-01

    The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

  8. Experimental and thermodynamic assessments of substitutions in the AlFeSi, FeMnSi, FeSiZr and AlCaFeSi systems (65 wt % Si) - solidification simulation

    International Nuclear Information System (INIS)

    Gueneau, C.; Ansara, I.

    1994-01-01

    The substitutions of Al Si, Fe Mn and Fe Zr in some intermetallic compounds of the Al-Fe-Si, Fe-Mn-Si and Fe-Si-Zr systems are modelled in the Si-rich corner using a two sublattice model. The solidification paths of the studied alloys are determined at equilibrium. The ascalculated phase volume fractions of the alloys are compared to the experimental ones. Finally, a solidification simulation using the Gulliver-Scheil's model is performed in order to explain the formation of some precipitates experimentally observed. (authors). 14 figs., 19 refs

  9. Magnetic and superconducting properties of Ir-doped EuFe2As2

    International Nuclear Information System (INIS)

    B Paramanik, U; Hossain, Z; L Paulose, P; Ramakrishnan, S; K Nigam, A; Geibel, C

    2014-01-01

    The magnetic and superconducting properties of 14% Ir-doped EuFe 2 As 2 are studied by means of dc and ac magnetic susceptibilities, electrical resistivity, specific heat and 151 Eu and 57 Fe Mössbauer spectroscopy (MS) measurements. Doping of Ir in EuFe 2 As 2 suppresses the Fe spin density wave transition and in turn gives rise to high temperature superconductivity below 22.5 K with a reentrant feature at lower temperature. Magnetization and 151 Eu Mössbauer data indicate that the Eu 2+ spins order magnetically below 18 K. 57 Fe MS studies show a line broadening in the absorption spectra below 18 K due to transferred hyperfine field from the magnetically ordered Eu sublattices. A pronounced λ-shape peak in the specific heat supports a second-order phase transition of Eu 2+ magnetic ordering with a strong ferromagnetic component, as confirmed by the magnetic field dependences of the transition. For a single crystal, the in-plane resistivity (ρ ab ) and out-of-plane susceptibility (χ c ) show superconducting transitions with zero resistance and diamagnetism, respectively. But the in-plane susceptibility (χ ab ) does not show any diamagnetic shielding against external fields. The observed non-zero resistance in the temperature range 10–17.5 K, below the superconducting transition temperature, suggests the possible existence of a spontaneous vortex state in this superconductor. (papers)

  10. Magnetic and structural properties of Cu0.85Fe0.15O system synthesized by co-precipitation

    International Nuclear Information System (INIS)

    Colorado, H. D.; Pérez Alcázar, G. A.

    2011-01-01

    Cu 0.94 Fe 0.06 O and Cu 0.85 Fe 0.15 O samples were synthesized by using the co-precipitation chemical method. Starting from aqueous solutions of copper nitrate, CuO (NO 3 ) 2 3H 2 O, iron nitrate, Fe (NO 3 ) 3 9H 2 O and sodium hydroxide as precipitating agent, NaOH. The precipitate of three samples for Cu 0.94 Fe 0.06 O and five for Cu 0.85 Fe 0.15 O of fine powder were calcined for 5 h at different temperatures. The obtained X rays diffraction patterns refined by the Rietveld method show the CuO characteristic pattern, showing that the Fe atoms enter to replace Cu atoms. Furthermore, it was obtained that the crystallite size decreases with calcination temperatures for Cu 0.94 Fe 0.06 O. The transmission Mössbauer spectroscopy showed that the samples present a disordered paramagnetic behavior due to the big value of the half-width of line of the quadrupolar splitting. Vibrating sample magnetometry confirms the paramagnetic character. The XRD results indicate that the material is nanostructured, due that the crystallite sizes are of the order of 10 nm for Cu 0.94 Fe 0.06 O and 40 nm for Cu 0.85 Fe 0.15 O.

  11. FeEDDHA-facilitated Fe uptake in relation to the behaviour of FeEDDHA components in the soil-plant system as a function of time and dosage.

    OpenAIRE

    Schenkeveld, W.D.C.; Temminghoff, E.J.M.; Reichwein, A.M.; Riemsdijk, van, W.H.

    2010-01-01

    FeEDDHA products are widely used to prevent and remedy Fe chlorosis in crops grown on calcareous soils. These products consist of a mixture of FeEDDHA components: racemic o,o-FeEDDHA, meso o,o-FeEDDHA, o,p-FeEDDHA and rest-FeEDDHA. The FeEDDHA components differ in physical and chemical properties, and as a consequence also in effectiveness as Fe fertilizer. In order to efficiently match dose, frequency and moment of FeEDDHA application with the Fe requirements of plants, it is important to un...

  12. The vertical metallicity gradient of the Milky Way disk: transitions in [α/Fe] populations

    International Nuclear Information System (INIS)

    Schlesinger, Katharine J.; Johnson, Jennifer A.; Rockosi, Constance M.; Lee, Young Sun; Beers, Timothy C.; Harding, Paul; Allende Prieto, Carlos; Bird, Jonathan C.; Schönrich, Ralph; Yanny, Brian; Schneider, Donald P.; Weaver, Benjamin A.; Brinkmann, Jon

    2014-01-01

    Using G dwarfs from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey, we have determined the vertical metallicity gradient in the Milky Way's disk and examined how this gradient varies for different [α/Fe] subsamples. Our sample contains over 40,000 stars with low-resolution spectroscopy over 144 lines of sight. It also covers a significant disk volume, between ∼0.3 and 1.6 kpc from the Galactic plane, and allows us to examine the disk in situ, whereas previous analyses were more limited in scope. Furthermore, this work does not presuppose a disk structure, whether composed of a single complex population or distinct thin and thick disk components. We employ the SEGUE Stellar Parameter Pipeline to obtain estimates of stellar parameters, [Fe/H], and [α/Fe] and extract multiple volume-complete subsamples of approximately 1000 stars each. Based on SEGUE's target-selection algorithm, we adjust each subsample to determine an unbiased picture of disk chemistry; consequently, each individual star represents the properties of many. The metallicity gradient is –0.243 −0.053 +0.039 dex kpc –1 for the entire sample, which we compare to various literature results. This gradient stems from the different [α/Fe] populations inhabiting different ranges of height above the Galactic plane. Each [α/Fe] subsample shows little change in median [Fe/H] with height. If we associate [α/Fe] with age, the negligible gradients of our [α/Fe] subsamples suggest that stars formed in different epochs exhibit comparable vertical structure, implying similar star formation processes and evolution.

  13. A (Si VI) (1.92 micrometer) coronal line survey of galactic nuclei

    Science.gov (United States)

    Marconi, A.; Moorwood, A. F. M.; Salvati, M.; Oliva, E.

    1994-11-01

    We present the results of a (Si VI) lambda 1.962 emission line survey of active, starburst and IRAS luminous galaxies. The line was only detected in known Seyfert type 1 and 2 nuclei confirming previous suggestions that (Si VI) is related to Seyfert activity. By modeling the formation of (Si VI) and (Fe VIII) lambda 6087 we find further strong evidence that these lines arise in gas photoionized by the active nucleus although collisional ionization e.g. by shock fronts may be important in some galaxies exhibiting (Fe VII) much greater than (Si VI). Our failure to detect (Si VI) in the IRAS ultraluminous galaxies does not exclude the possible presence of obscured Active Galactic Nuclei (AGNs), particularly as some of the known Seyferts were also not detected. Molecular hydrogen lines (a by-product of our spectra) are common in all galaxy types including several IRAS ultraluminous galaxies whose H2 equivalent widths (Wlambda less that 20 A) are 'normal'and much lower than the extreme value (Wlambda approximately = 70 A) found in NGC 6240 and NGC 1275. 'Bare' Seyferts have Wlambda(H2) less than 1 A and a factor greater than or approximately 10 lower than starbursts, and we do not confirm previous claims of H2 line emission in the quasar 3C273. Although the ratio of H2 to (Si VI) emission varies over a wide range it does not appear to provide a useful indicator of activity type or to impose constraints on the He excitation mechanism.

  14. Synthesis and characterization of magnetic Fe/CNTs composites with controllable Fe nanoparticle concentration

    International Nuclear Information System (INIS)

    Zhao Fan; Duan Hongyan; Wang Weigao; Wang Jun

    2012-01-01

    Fe/CNTs composites, with different concentrations of Fe nanoparticles (NPs) on carbon nanotube (CNT) surfaces, were successfully fabricated via a facile solvothermal method. The lengths of CNTs are up to 10 μm and the mean diameter of the Fe nanoparticles is about 25 nm. The structures, composition and magnetic properties of the Fe/CNTs were characterized by XRD, FTIR, FE-SEM, TEM and PPMS. We found that the concentrations of Fe nanoparticles depositing on the CNTs could be controlled by adjusting the initial mass ratio of ferrocene to CNTs. The Fe/CNTs composites display good ferromagnetic properties at room temperature, with a saturation magnetization of 125 emu/g-Fe and a coercivity of 276 Oe. The Curie temperature of the sample is about 1038 K, slightly lower than that (1043 K) of the bulk iron.

  15. Formation and stability of Fe-rich precipitates in dilute Zr(Fe) single-crystal alloys

    International Nuclear Information System (INIS)

    Zou, H.; Hood, G.M.; Roy, J.A.; Schultz, R.J.

    1993-02-01

    The formation and stability of Fe-rich precipitates in two α-Zr(Fe) single-crystal alloys with nominal compositions (I, 50 ppma Fe, and II, 650 ppma Fe) have been investigated (the maximum solid solubility of Fe in α-Zr is 180 ppma - 800 C). Optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to examine the characteristics of Fe-rich precipitates. SEM and TEM micrographs show that in as-grown alloy II, Zr 2 Fe precipitates are located at 'stringers'. Precipitates were not observed in as-grown alloy I. During annealing, below the solvus, Fe diffuses to the surfaces to form Zr 3 Fe precipitates in both alloys. The precipitates on the surfaces of alloy I tend to be star-like (0001) or pyramidal (1010), and their distribution is heterogeneous. Dissolution of Zr 3 Fe surface precipitates of alloy I (annealing above the solvus) leaves precipitate-like features on the surfaces. Zr 2 Fe precipitates in as-grown alloy II can be dissolved only by β-phase annealing. (Author) 8 figs., 18 refs

  16. Fast neutron Damage Studies on NdFeB Materials

    OpenAIRE

    Anderson, S.; Spencer, J.; Wolf, Z.; Boussoufi, M.; Baldwin, A.; Pellett, D.; Volk, J.

    2005-01-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and gamma’s over the life of the facility. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at the P...

  17. Investigation of the effect of Hollow Cathode in a Grimm-type source (Ar) on the excitation processes using Fe samples

    International Nuclear Information System (INIS)

    Weinstein, V.; Steers, E.B.M.

    2009-01-01

    Complete text of publication follows. Analytical spectroscopic applications using a Grimm Glow Discharge source sometimes require an increased sensitivity and therefore a higher signal to background ratio, which can be reached by using hollow cathode (HC) instead of plane samples. At the beginning of the 20 th century, intensity enhancements of emission lines using HC were observed and explained by longer residence time of sample atoms and consequently more collisional excitation. Later a HC was used with a Grimm source, to achieve higher sensitivity for lines of minor constituents. Recently the HC effect was further investigated for several metallic samples with a commercial GD-OES instrument (T.Gusarova., J. Anal. At. Spectrom., 2009., DOI: 10.1039/b814977a) for improvement of the signal to background ratio (SBR). The intensities and SBR from HC and plane cathode were compared, but only one or two lines could be observed for each element in the sample. The line intensities using plane and HC samples depend on the excitation processes occurring in the two cases. To make conclusions about the excitation mechanism differences, a large number of lines should be examined. Therefore we have recorded spectra over a wide wavelength range (approx. 200-600 nm) using a Fourier Transform Spectrometer (FTS), which allows simultaneous recording of spectra with a very high resolution. The 15 mm deep Fe HC sample and Fe plane cathode sample were analysed using argon as the carrier gas. The comparison of the data was made by calculating the ratio of intensities obtained from the HC sample to intensities of the plane cathode sample and plotting this against the excitation energy of Fe I, Fe II and Ar I, Ar II emission lines. Such plots link the intensity differences with the upper levels of the transitions and so help to clarify the relative importance of excitation processes. The experiments were also carried out at different currents, therefore the effect of the current on

  18. FeEDDHA-facilitated Fe uptake in relation to the behaviour of FeEDDHA components in the soil-plant system as a function of time and dosage.

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.; Temminghoff, E.J.M.; Reichwein, A.M.; Riemsdijk, van W.H.

    2010-01-01

    FeEDDHA products are widely used to prevent and remedy Fe chlorosis in crops grown on calcareous soils. These products consist of a mixture of FeEDDHA components: racemic o,o-FeEDDHA, meso o,o-FeEDDHA, o,p-FeEDDHA and rest-FeEDDHA. The FeEDDHA components differ in physical and chemical properties,

  19. Predictive FEM simulation of thermal shock damage in the refractory lining of steelmaking installations

    NARCIS (Netherlands)

    Damhof, F.; Brekelmans, W.A.M.; Geers, M.G.D.

    2011-01-01

    Thermal shock damage in the refractory lining of steelmaking installations is modelled using an experimentally validated constitutive damage framework which is coupled incrementally with a thermo-elastic FE package. Both non-local elasticity-based damage induced by temperature gradients and thermal

  20. The influence of a Cr-dopant on the properties of α-FeOOH particles precipitated in highly alkaline media

    International Nuclear Information System (INIS)

    Krehula, Stjepko; Music, Svetozar

    2009-01-01

    The effects of a Cr-dopant on the precipitation of acicular α-FeOOH particles, the formation of solid solutions, particle size and shape were investigated using X-ray powder diffraction (XRD), Moessbauer and Fourier transform infrared (FT-IR) spectroscopies and field emission scanning electron microscopy (FE-SEM). Acicular and monodisperse α-FeOOH particles were precipitated at a very high pH by heating the suspension obtained by adding a tetramethylammonium hydroxide solution to an aqueous solution of FeCl 3 . The influence of the Cr-dopant was investigated by addition of various amounts of Cr 3+ ions to the initial FeCl 3 solution, where r = 100[Cr]/([Cr] + [Fe]) stands for the added amount of Cr. XRD analysis of the obtained powders (with r values from 0 to 23.08) showed only the presence of the diffraction lines characteristic for α-FeOOH. Moessbauer spectroscopy showed a decrease in hyperfine magnetic field of α-FeOOH with an increase in Cr addition which indicates Cr incorporation into the α-FeOOH structure. The OH bending bands in the FT-IR spectra showed only a slight change in position with an increase in r, but the considerable increase in the lattice band wave number indicated a decrease in thickness of the lath-like α-FeOOH particles. This conclusion was confirmed by FE-SEM observations

  1. DISCOVERY OF ULTRA-FAST OUTFLOWS IN A SAMPLE OF BROAD-LINE RADIO GALAXIES OBSERVED WITH SUZAKU

    International Nuclear Information System (INIS)

    Tombesi, F.; Sambruna, R. M.; Mushotzky, R. F.; Reeves, J. N.; Gofford, J.; Braito, V.; Ballo, L.; Cappi, M.

    2010-01-01

    We present the results of a uniform and systematic search for blueshifted Fe K absorption lines in the X-ray spectra of five bright broad-line radio galaxies observed with Suzaku. We detect, for the first time in radio-loud active galactic nuclei (AGNs) at X-rays, several absorption lines at energies greater than 7 keV in three out of five sources, namely, 3C 111, 3C 120, and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blueshifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range v ≅ 0.04-0.15c. A fit with specific photoionization models gives ionization parameters in the range log ξ ≅ 4-5.6 erg s -1 cm and column densities of N H ≅ 10 22 -10 23 cm -2 . These characteristics are very similar to those of the ultra-fast outflows (UFOs) previously observed in radio-quiet AGNs. Their estimated location within ∼0.01-0.3 pc of the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN to the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGNs.

  2. Fe(II)/Fe(III)-Catalyzed Intramolecular Didehydro-Diels-Alder Reaction of Styrene-ynes.

    Science.gov (United States)

    Mun, Hyeon Jin; Seong, Eun Young; Ahn, Kwang-Hyun; Kang, Eun Joo

    2018-02-02

    The intramolecular didehydro-Diels-Alder reaction of styrene-ynes was catalyzed by Fe(II) and Fe(III) to produce various naphthalene derivatives under microwave heating conditions. Mechanistic calculations found that the Fe(II) catalyst activates the styrenyl diene in an inverse-electron-demand Diels-Alder reaction, and the consecutive dehydrogenation reaction can be promoted by either Fe(II)-catalyzed direct dehydrogenation or an Fe(III)-catalyzed rearomatization/dehydrogenation pathway.

  3. Mössbauer spectroscopic studies in U-Fe and U-Fe-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Alaka; Singh, L. Herojit; Rajagopalan, S.; Govindaraj, R., E-mail: govind@igcar.gov.in; Ramachandran, Renjith; Kalavathi, S.; Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2016-05-23

    {sup 57}Fe Mössbauer studies have been carried out in an alloy of U and Fe with atomic percentage in the ratio of 68%:32% in order to understand the local structure and valence of Fe atoms associated with different phases that may get formed. The effect of changes in the hyperfine parameters such as isomer shift and quadrupole splitting at Fe sites due to additional alloying of Zr has been studied in an alloy of U, Fe and Zr in the ratio of 44%:33%:23% respectively with respect to that of the U-Fe alloy chosen in the present study. Possible effect of solute clustering in these systems has been addressed in an analogous alloy of uranium and zirconium using positron lifetime spectroscopy.

  4. arXiv Proceedings, High-Precision $\\alpha_s$ Measurements from LHC to FCC-ee Geneva, Switzerland, October 2-13, 2015

    CERN Document Server

    d'Enterria, David; Alekhin, S.; Banfi, A.; Bethke, S.; Blümlein, J.; Chetyrkin, K.G.; Dissertori, G.; Garcia i Tormo, X.; Hoang, A.H.; Klasen, M.; Klijnsma, T.; Kluth, S.; Kneur, J.-L.; Kniehl, B.A.; Kolodrubetz, D.W.; Kühn, J.; Mackenzie, P.; Malaescu, B.; Mateu, V.; Mihaila, L.; Moch, S.; Mönig, K.; Pérez-Ramos, R.; Pich, A.; Pires, J.; Rabbertz, K.; Salam, G.P.; Sannino, F.; Soto i Riera, J.; Srebre, M.; Stewart, I.W.

    2015-01-01

    This document provides a writeup of all contributions to the workshop on "High precision measurements of $\\alpha_s$: From LHC to FCC-ee" held at CERN, Oct. 12--13, 2015. The workshop explored in depth the latest developments on the determination of the QCD coupling $\\alpha_s$ from 15 methods where high precision measurements are (or will be) available. Those include low-energy observables: (i) lattice QCD, (ii) pion decay factor, (iii) quarkonia and (iv) $\\tau$ decays, (v) soft parton-to-hadron fragmentation functions, as well as high-energy observables: (vi) global fits of parton distribution functions, (vii) hard parton-to-hadron fragmentation functions, (viii) jets in $e^\\pm$p DIS and $\\gamma$-p photoproduction, (ix) photon structure function in $\\gamma$-$\\gamma$, (x) event shapes and (xi) jet cross sections in $e^+e^-$ collisions, (xii) W boson and (xiii) Z boson decays, and (xiv) jets and (xv) top-quark cross sections in proton-(anti)proton collisions. The current status of the theoretical and experiment...

  5. Preclinical In Vitro and In Vivo Evaluation of [18F]FE@SUPPY for Cancer PET Imaging: Limitations of a Xenograft Model for Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    T. Balber

    2018-01-01

    Full Text Available Molecular imaging probes such as PET-tracers have the potential to improve the accuracy of tumor characterization by directly visualizing the biochemical situation. Thus, molecular changes can be detected early before morphological manifestation. The A3 adenosine receptor (A3AR is described to be highly expressed in colon cancer cell lines and human colorectal cancer (CRC, suggesting this receptor as a tumor marker. The aim of this preclinical study was the evaluation of F18FE@SUPPY as a PET-tracer for CRC using in vitro imaging and in vivo PET imaging. First, affinity and selectivity of FE@SUPPY and its metabolites were determined, proving the favorable binding profile of FE@SUPPY. The human adenocarcinoma cell line HT-29 was characterized regarding its hA3AR expression and was subsequently chosen as tumor graft. Promising results regarding the potential of F18FE@SUPPY as a PET-tracer for CRC imaging were obtained by autoradiography as ≥2.3-fold higher accumulation of F18FE@SUPPY was found in CRC tissue compared to adjacent healthy colon tissue from the same patient. Nevertheless, first in vivo studies using HT-29 xenografts showed insufficient tumor uptake due to (1 poor conservation of target expression in xenografts and (2 unfavorable pharmacokinetics of F18FE@SUPPY in mice. We therefore conclude that HT-29 xenografts are not adequate to visualize hA3ARs using F18FE@SUPPY.

  6. Contribution to the Study of the Relation between Microstructure and Electrochemical Behavior of Iron-Based FeCoC Ternary Alloys

    Directory of Open Access Journals (Sweden)

    Farida Benhalla-Haddad

    2012-01-01

    Full Text Available This work deals with the relation between microstructure and electrochemical behavior of four iron-based FeCoC ternary alloys. First, the arc-melted studied alloys were characterized using differential thermal analyses and scanning electron microscopy. The established solidification sequences of these alloys show the presence of two primary crystallization phases (δ(Fe and graphite as well as two univariante lines : peritectic L+(Fe↔(Fe and eutectic L↔(Fe+Cgraphite. The ternary alloys were thereafter studied in nondeaerated solution of 10−3 M NaHCO3 + 10−3 M Na2SO4, at 25°C, by means of the potentiodynamic technique. The results indicate that the corrosion resistance of the FeCoC alloys depends on the carbon amount and the morphology of the phases present in the studied alloys.

  7. Reactions of laser-ablated iron atoms and cations with carbon monoxide: Infrared spectra of FeCO+, Fe(CO)2+, Fe(CO)x, and Fe(CO)x- (x=1-4) in solid neon

    Science.gov (United States)

    Zhou, Mingfei; Andrews, Lester

    1999-06-01

    Laser-ablated iron atoms, cations, and electrons have been reacted with CO molecules during condensation in excess neon. The FeCO molecule is observed at 1933.7 cm-1 in solid neon. Based on isotopic shifts and density functional calculations, the FeCO molecule has the same 3Σ- ground state in solid neon that has been observed at 1946.5 cm-1 in a recent high resolution gas phase investigation [Tanaka et al., J. Chem. Phys. 106, 2118 (1997)]. The C-O stretching vibration of the Fe(CO)2 molecule is observed at 1917.1 cm-1 in solid neon, which is in excellent agreement with the 1928.2 cm-1 gas phase value for the linear molecule. Anions and cations are also produced and trapped, absorptions at 1782.0, 1732.9, 1794.5, and 1859.7 cm-1 are assigned to the linear FeCO-, Fe(CO)2-, trigonal planar Fe(CO)3-, and C3v Fe(CO)4- anions, respectively, and 2123.0, 2134.0 cm-1 absorptions to the linear FeCO+ and Fe(CO)2+ cations. Doping these experiments with CCl4 virtually eliminates the anion absorptions and markedly increases the cation absorptions, which confirms the charge identifications. Higher iron carbonyl Fe(CO)3, Fe(CO)4, and Fe(CO)5 absorptions are produced on photolysis.

  8. The role of water in generating Fe-depletion and the calc-alkaline trend

    Science.gov (United States)

    Zimmer, M. M.; Plank, T.

    2006-12-01

    Describing a magmatic suite as calc-alkaline (CA) or tholeiitic (TH) is a first order characterization, but existing classification schemes (AFM ternary plots and FeO*/MgO vs. SiO2) may convolute magmatic processes and can result in contradictory classification. The salient feature of TH vs. CA evolution is the extent of Fe enrichment or depletion in the magma. A plot of FeO* vs. MgO provides the most straightforward way to quantify Fe enrichment and to develop models for its origin. We present a new quantitative classification utilizing the FeO*-MgO plot, the tholeiitic index (THI) = Fe3-5/Fe8 (Fe3-5=average FeO* at 3-5 wt% MgO; Fe8=FeO* at 8 wt% MgO). THI of 1.2 indicates 20% FeO* enrichment from a magma's starting composition at Fe8, while THI of 0.8 indicates 20% depletion in FeO*. A magmatic suite is CA if THI is TH if THI is >1. Arcs range from 0.6 to 1.1, back arc basins from 1.1-1.3, and MORBs are \\ge1.6. This classification allows comparison of magmatic evolution on a global basis, regardless of starting composition, and is useful for quantitative comparison to liquid line of descent models. Hypotheses for generating CA magmas include high water contents, high pressure of crystallization, high oxygen fugacity, and high Mg# andesitic starting compositions. In order to test the control of H2O, we compare the THI to average magmatic water contents from undegassed melt inclusions and glasses (S>1000 ppm or CO2>50 ppm) from twenty-eight arc volcanoes and back arc basins, including new water contents from seven Aleutian volcanoes. The resulting negative correlation (R2=0.8) between water concentration and THI (with end-members at 0.8 wt% H2O, THI =1.3 and 6.1 wt% H2O, THI = 0.6) suggests water plays a fundamental role in generating the CA fractionation trend. MORB data plot off the trend at a higher THI, possibly related to lower oxygen fugacity during melting and/or crystallization. Models using the pMelts program are consistent with experimentally- and

  9. Stability of the high pressure phase Fe3S2 up to Earth's core pressures in the Fe-S-O and the Fe-S-Si systems

    Science.gov (United States)

    Zurkowski, C. C.; Chidester, B.; Davis, A.; Brauser, N.; Greenberg, E.; Prakapenka, V. B.; Campbell, A.

    2017-12-01

    Earth's core is comprised of an iron-nickel alloy that contains 5-15% of a light element component. The abundance and alloying capability of sulfur, silicon and oxygen in the bulk Earth make them important core alloy candidates; therefore, the high-pressure phase equilibria of the Fe-S-O and Fe-S-Si systems are relevant for understanding the possible chemistry of Earth's core. Previously, a Fe3S2 phase was recognized as a low-pressure intermediate phase in the Fe-FeS system that is stable from 14-21 GPa, but the structure of this phase has not been resolved. We report in-situ XRD and chemical analysis of recovered samples to further examine the stability and structure of Fe3S2 as it coexists with other phases in the Fe-S-O and Fe-S-Si systems. In situ high P-T synchrotron XRD experiments were conducted in the laser-heated diamond anvil cell to determine the equilibrium phases in Fe75S7O18 and Fe80S5Si15 compositions between 30 and 174 GPa and up to 3000 K. In the S,O-rich samples, an orthorhombic Fe3S2 phase coexists with hcp-Fe, Fe3S and FeO and undergoes two monoclinic distortions between 60 and 174 GPa. In the S,Si-rich samples, the orthorhombic Fe3S2 phase was observed up to 115 GPa. With increasing pressure, the Fe3S2 phase becomes stable to higher temperatures in both compositions, suggesting possible Fe3(S,O)2 or Fe3(S,Si)2 solid solutions. SEM analysis of a laser heated Fe75S7O18 sample recovered from 40 GPa and 1450 K confirms a Fe3(S,O)2 phase with O dissolved into the structure. Based on the current melting data in the Fe-S-O and Fe-S-Si systems, the Fe3(S,O)2 stability field intersects the solidus in the outer core and could be a possible liquidus phase in Fe,S,O-rich planetary cores, whereas Fe3S is the stable sulfide at outer core pressures in Fe,S,Si-rich systems.

  10. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    International Nuclear Information System (INIS)

    Miko, Annamaria; Kuzmann, Erno; Lakatos-Varsanyi, Magda; Kakay, Attila; Nagy, Ferenc; Varga, Lajos Karoly

    2005-01-01

    57 Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and 57 Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm -2 ) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm -2 ). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  11. Characterization of rust layer formed on Fe, Fe-Ni and Fe-Cr alloys exposed to Cl-rich environment by Cl and Fe K-edge XANES measurements

    International Nuclear Information System (INIS)

    Konishi, Hiroyuki; Mizuki, Jun'ichiro; Yamashita, Masato; Uchida, Hitoshi

    2005-01-01

    Chloride in atmosphere considerably reduces the corrosion resistance of conventional weathering steel containing a small amount of Cr. Ni is an effective anticorrosive element for improving the corrosion resistance of steel in a Cl-rich environment. In order to clarify the structure of the protective rust layer of weathering steel, Cl and Fe K-edge X-ray absorption near edge structure (XANES) spectra of atmospheric corrosion products (rust) formed on Fe, Fe-Ni and Fe-Cr alloys exposed to Cl-rich atmosphere were measured. The Fe K-XANES measurements enable the characterization of mixture of iron oxides such as rust. The chemical composition of the rust was determined by performing pattern fitting of the measured spectra. All the rust is composed mainly of goethite, akaganeite, lepidocrocite and magnetite. Among these iron oxides, akaganeite in particular is the major component in the rust. Additionally, the amount of akaganeite in the rust of Fe-Ni alloy is much greater than that in rust of Fe-Cr alloy. Akaganeite is generally considered to facilitate the corrosion of steel, but our results indicate that akaganeite in the rust of Fe-Ni alloy is quantitatively different from that in rust of Fe-Cr alloy and does not facilitate the corrosion of steel. The shoulder peak observed in Cl K-XANES spectra reveals that the rust contains a chloride other than akaganeite. The energy of the shoulder peak does not correspond to that of any well-known chlorides. In the measured spectra, there is no proof that Cl, by combining with the alloying element, inhibits the alloying element from acting in corrosion resistance. The shoulder peak appears only when the content of the alloying element is lower than a certain value. This suggests that the generation of the unidentified chloride is related to the corrosion rate of steel. (author)

  12. Speciative Determination of Dissolved Inorganic Fe(II), Fe(III) and Total Fe in Natural Waters by Coupling CPE with FAAS

    International Nuclear Information System (INIS)

    Gurkan, R.; Altunay, N.

    2013-01-01

    A new cloud point extraction (CPE) method for the preconcentration of trace iron speciation in natural waters prior to determination by flame atomic absorption spectrometry (FAAS) was developed in the present study. In this method, Fe(II) sensitively and selectively reacts with Calcon carboxylic acid (CCA) in presence of cetylpyridinium chloride (CPC) yielding a hydrophobic complex at pH 10.5, which is then entrapped in surfactant-rich phase. Total Fe was accurately and reliably determined after the reduction of Fe(III) to Fe(II) with sulfite. The amount of Fe(III) in samples was determined from the difference between total Fe and Fe(II). CPC was used not only as an auxiliary ligand in CPE, but also as sensitivity enhancement agent in FAAS. The nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114) was used as an extracting agent. The analytical variables affecting CPE efficiency were investigated in detail. The preconcentration/enhancement factors of 50 and 82 respectively, were obtained for the preconcentration of Fe(II) with 50 mL solution. Under the optimized conditions, the detection limit of Fe(II) in linear range of 0.2-60 μg L/sup -1/ was 0.06 μg L/sup -1/. The relative standard deviation was 2.7 percentage (20 μg L/sup -1/, N: 5), recoveries for Fe(II) were in range of 99.0-102.0 percentage for all water samples including certified reference materials (CRMs). In order to verify its accuracy, two CRMs were analyzed and the results obtained were statistically in good agreement with the certified values. (author)

  13. The thermal evolution of Mercury's Fe-Si core

    Science.gov (United States)

    Knibbe, Jurriën Sebastiaan; van Westrenen, Wim

    2018-01-01

    We have studied the thermal and magnetic field evolution of planet Mercury with a core of Fe-Si alloy to assess whether an Fe-Si core matches its present-day partially molten state, Mercury's magnetic field strength, and the observed ancient crustal magnetization. The main advantages of an Fe-Si core, opposed to a previously assumed Fe-S core, are that a Si-bearing core is consistent with the highly reduced nature of Mercury and that no compositional convection is generated upon core solidification, in agreement with magnetic field indications of a stable layer at the top of Mercury's core. This study also present the first implementation of a conductive temperature profile in the core where heat fluxes are sub-adiabatic in a global thermal evolution model. We show that heat migrates from the deep core to the outer part of the core as soon as heat fluxes at the outer core become sub-adiabatic. As a result, the deep core cools throughout Mercury's evolution independent of the temperature evolution at the core-mantle boundary, causing an early start of inner core solidification and magnetic field generation. The conductive layer at the outer core suppresses the rate of core growth after temperature differences between the deep and shallow core are relaxed, such that a magnetic field can be generated until the present. Also, the outer core and mantle operate at higher temperatures than previously thought, which prolongs mantle melting and mantle convection. The results indicate that S is not a necessary ingredient of Mercury's core, bringing bulk compositional models of Mercury more in line with reduced meteorite analogues.

  14. Emission lines of [K V] in the optical spectra of gaseous nebulae.

    Science.gov (United States)

    Keenan, Francis P; Aller, Lawrence H; Espey, Brian R; Exter, Katrina M; Hyung, Siek; Keenan, Michael T C; Pollacco, Don L; Ryans, Robert S I

    2002-04-02

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 A)/I(4163.3 A) as a function of electron density (N(e)). This ratio is found to be very sensitive to changes in N(e) over the density range 10(3) to 10(6) cm(-3), but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical N(e) diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope, reveals that the [K v] 4122.6 A line in this object is badly blended with Fe ii 4122.6 A. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum.

  15. Moessbauer studies of superexchange interactions in NiFe sub 2 O sub 4

    CERN Document Server

    Kim, S J; Kim, C S; Lee, S W

    2000-01-01

    NiFe sub 2 O sub 4 has been studied using Moessbauer spectroscopy and X-ray diffraction. The crystal was found to have a inverse cubic spinel structure with the lattice constant a sub 0 =8.326+-0.003 A. Moessbauer spectra of NiFe sub 2 O sub 4 was obtained at various absorber temperatures from 13 K to the Neel temperature. The Moessbauer spectra consisted of two sets of six lines corresponding to Fe sup + sup 3 at the tetrahedral (A) and the octahedral (B) sites. The temperature dependence of the magnetic hyperfine fields at sup 5 sup 7 Fe nuclei at the tetrahedral (A) and the octahedral (B) sites was analyzed by the Neel theory of ferrimagnetism. The intersublattice A-O-B and intrasublattice A-O-A superexchange interactions were found to be antiferromagnetic with strengths of J sub A sub - sub B =-25.0 k sub B and J sub A sub - sub A =-4.0 K sub B , respectively, while the intrasublattice B-O-B superexchange interaction is ferromagnetic with a strength J sub B sub - sub B =4.2 k sub B.

  16. Properties of porous FeAlOy/FeAlx ceramic matrix composite ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 7. Properties of porous FeAlO/FeAl ceramic matrix composite influenced by mechanical activation of FeAl powder. V Usoltsev S Tikhov A Salanov V Sadykov G Golubkova O Lomovskii. Volume 36 Issue 7 December 2013 pp 1195-1200 ...

  17. Obtention of the TiFe compound by high-energy milling of Ti+Fe and TiH{sub 2}+Fe powder mixtures; Obtencao do composto TiFe a partir da moagem de alta energia de misturas Ti+Fe e TiH{sub 2}+Fe

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, R.B.; Dammann, E.D.C.C.; Rocha, C.J.; Leal Neto, R.M., E-mail: railson.falcao@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais. Lab. de Intermetalicos

    2010-07-01

    In this work TiFe compound was obtained by two process routes involving high-energy ball milling: mechanical alloying from Ti and Fe powders (route 1) and mechanical milling from TiH{sub 2} and Fe powders, both followed by an annealing heat treatment. Shaker and planetary ball mills were utilized for times varying from 1-25 hours. Milled and annealed powders were characterized by SEM and X-ray diffraction analyses. TiFe compound was formed in both routes. A strong powder adherence in the milling vial and balls occurred with route 1 in both mills. Powder adherence was significantly reduced by using TiH{sub 2} (route 2) mainly in the planetary mill, in spite of TiFe formation has only occurred after the annealing treatment. (author)

  18. Spectrophotometric speciation of Fe(II) and Fe(III) using hydrazone-micelle systems and flow injections

    International Nuclear Information System (INIS)

    Khojali, Inas Osman

    1999-04-01

    Two hydrazones were synthesised, namely salicylhyrazone (SH) and trihydroxyacetophenone (THAPH) were synthesised with the objective of developing a method for determining of Fe(II) and Fe(III) in the presence of each other and hence the total iron.those hydrazones were selected so as to combine the ability of phenolic compounds to complex Fe(III) ions and the complexing characteristics of hydrazones. The complexes of Fe(II) S H and Fe(III) S H as well those of Fe(II)-THAPH and Fe(III)-THAPH had shown maximum absorbance at λ=412 nm which was not not modified by presence of micelles i.e. sodium n-dodecyl sulphate (SDS) and n-hexa dodecyl pyridinium bromide. The maximum absorbance for all complexes takes place around a neutral pH. Generally, in addition, of n-hexa dodecylpyridinium bromide to fe(II)-SH and Fe(III)-SH absorbance of the complexes increases with increasing the concentration of the micelle. The effects of the addition of sodium n-dodecyle sulphate (SDS) to Fe(III)-SH is also studied. Generally, increasing the concentration of the micelle decrease the absorbance of the complexes. To study the effect of the presence of Fe(II) and Fe(III) on the determination of each other,mixtures of Fe(II)-SH and Fe(III)-SH are studied. However, the use of ascorbic acid as a reducing reagent for Fe(III) did not produce the needed results but non reducible results, which may be due to the masking effect of ascorbic acid and thus making the metal not available to the ligand. However, conversion of Fe(II) to Fe(III) prior to the determination was avoided as this requires the use of oxidant, which will oxidise the ligand as well. To establish the condition for the maximum absorbance of THAPH complexes, the effect of the base was investigated by using sodium and ammonium hydroxide. Generally, increasing the concentration of the base decreases the abosrbance. as expected, ammonium hydroxide produced positive results than sodium hydroxide. After establishing the optimum Fi

  19. CO-Bridged H-Cluster Intermediates in the Catalytic Mechanism of [FeFe]-Hydrogenase CaI.

    Science.gov (United States)

    Ratzloff, Michael W; Artz, Jacob H; Mulder, David W; Collins, Reuben T; Furtak, Thomas E; King, Paul W

    2018-06-20

    The [FeFe]-hydrogenases ([FeFe] H 2 ases) catalyze reversible H 2 activation at the H-cluster, which is composed of a [4Fe-4S] H subsite linked by a cysteine thiolate to a bridged, organometallic [2Fe-2S] ([2Fe] H ) subsite. Profoundly different geometric models of the H-cluster redox states that orchestrate the electron/proton transfer steps of H 2 bond activation have been proposed. We have examined this question in the [FeFe] H 2 ase I from Clostridium acetobutylicum (CaI) by Fourier-transform infrared (FTIR) spectroscopy with temperature annealing and H/D isotope exchange to identify the relevant redox states and define catalytic transitions. One-electron reduction of H ox led to formation of H red H + ([4Fe-4S] H 2+ -Fe I -Fe I ) and H red ' ([4Fe-4S] H 1+ -Fe II -Fe I ), with both states characterized by low frequency μ-CO IR modes consistent with a fully bridged [2Fe] H . Similar μ-CO IR modes were also identified for H red H + of the [FeFe] H 2 ase from Chlamydomonas reinhardtii (CrHydA1). The CaI proton-transfer variant C298S showed enrichment of an H/D isotope-sensitive μ-CO mode, a component of the hydride bound H-cluster IR signal, H hyd . Equilibrating CaI with increasing amounts of NaDT, and probed at cryogenic temperatures, showed H red H + was converted to H hyd . Over an increasing temperature range from 10 to 260 K catalytic turnover led to loss of H hyd and appearance of H ox , consistent with enzymatic turnover and H 2 formation. The results show for CaI that the μ-CO of [2Fe] H remains bridging for all of the "H red " states and that H red H + is on pathway to H hyd and H 2 evolution in the catalytic mechanism. These results provide a blueprint for designing small molecule catalytic analogs.

  20. Magnetic and structural characterizations on nanoparticles of FePt, FeRh and their composites

    International Nuclear Information System (INIS)

    Ko, Hnin Yu Yu; Suzuki, Takao; Nam, Nguyen T.; Phuoc, Nguyen N.; Cao Jiangwei; Hirotsu, Yoshihiko

    2008-01-01

    The various compositions of FePt and FeRh nanoparticles, and their composite particles have been fabricated by the solution-phase chemical method and their magnetic properties characterized. High-resolution transmission electron microscopic observations indicate that mono-dispersed FeRh and FePt/FeRh nanoparticles are fabricated with the average size of 3-5 nm. However, larger size particles are distributed in the annealed state. From X-ray diffraction results, the as-deposited FeRh nanoparticles reveal a chemically disordered fcc structure which can be transformed into CsCl-type structure through thermal annealing. Similarly, the annealed FePt nanoparticles show the L1 0 -phase fct structure although the fcc structure is apparent in the as-deposited state. It is also found that the first time in the exchange bias effect in the composite of ferromagnetic (FePt) and anti-ferromagnetic (FeRh) nanoparticles; result in a shift of the hysteresis loop after field cooling process

  1. Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Miko, Annamaria [Bay Zoltan Institute for Material Science (Hungary); Kuzmann, Erno, E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Lakatos-Varsanyi, Magda [Bay Zoltan Institute for Material Science (Hungary); Kakay, Attila [Research Institute for Solid State Physics and Optics (Hungary); Nagy, Ferenc [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics (Hungary)

    2005-09-15

    {sup 57}Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and {sup 57}Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t{sub on} = 2 ms), with short relaxation time (t{sub off} = 9 ms) and low current density (I{sub p} = 0.05 Acm{sup -2}) or at short deposition time (t{sub on} = 1 ms) with long relaxation time (t{sub off} = 250 ms) and high current density (I{sub p} = 1.0 Acm{sup -2}). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

  2. Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

    Science.gov (United States)

    Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; Till, Claire P.; Lee, Jong-Mi; Toner, Brandy M.; Marcus, Matthew A.

    2017-08-01

    Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). We present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.

  3. Structural and magnetic study of mechanically deformed Fe rich FeAlSi ternary alloys

    International Nuclear Information System (INIS)

    Legarra, E.; Apiñaniz, E.; Plazaola, F.

    2012-01-01

    Highlights: ► Addition of Si to binary Fe–Al alloys makes the disordering more difficult. ► Si addition opposes the large volume increase found in FeAl alloys with deformation. ► Disordering induces a redistribution of non-ferrous atoms around Fe atoms in Fe 75 Al 25−x Si x and Fe 70 Al 30−x Si x . ► Addition of Si to binary Fe 75 Al 25 and Fe 70 Al 30 alloys opposes the magnetic behavior induced by Al in the magnetism of Fe. ► Si inhibits the para-ferro transition found in Fe 60 Al 40 alloy with disordering. - Abstract: In this work we study systematically the influence of different Al/Si ratios on the magnetic and structural properties of mechanically disordered powder Fe 75 Al 25−x Si x , Fe 70 Al 30−x Si x and Fe 60 Al 40−x Si x alloys by means of Mössbauer spectroscopy, X-ray diffraction and magnetic measurements. In order to obtain different stages of disorder the alloys were deformed by different methods: crushing induction melted alloys and ball milling annealed (ordered) alloys using different number of balls and speed. X-ray and Mössbauer data show that mechanical deformation induces the disordered A2 structure in these alloys. The results indicate that addition of Si to binary Fe–Al alloys makes the disordering more difficult. In addition, X-ray diffraction patterns show that the normalized lattice parameter variation of the disordered alloys of each composition decreases monotonically with Si content, indicating clearly that Si addition opposes the large volume increase found in FeAl alloys with deformation. The study of the hyperfine fields indicates that there is a redistribution of non-ferrous atoms around Fe atoms with the disordering; indeed, there is an inversion of the behavior of the hyperfine field of the Fe atoms. On the other hand, the magnetic measurements indicate that addition of Si to binary Fe 75 Al 25 and Fe 70 Al 30 alloys opposes the magnetic behavior induced by Al in the magnetism of Fe.

  4. Topological Superconductivity on the Surface of Fe-Based Superconductors.

    Science.gov (United States)

    Xu, Gang; Lian, Biao; Tang, Peizhe; Qi, Xiao-Liang; Zhang, Shou-Cheng

    2016-07-22

    As one of the simplest systems for realizing Majorana fermions, the topological superconductor plays an important role in both condensed matter physics and quantum computations. Based on ab initio calculations and the analysis of an effective 8-band model with superconducting pairing, we demonstrate that the three-dimensional extended s-wave Fe-based superconductors such as Fe_{1+y}Se_{0.5}Te_{0.5} have a metallic topologically nontrivial band structure, and exhibit a normal-topological-normal superconductivity phase transition on the (001) surface by tuning the bulk carrier doping level. In the topological superconductivity (TSC) phase, a Majorana zero mode is trapped at the end of a magnetic vortex line. We further show that the surface TSC phase only exists up to a certain bulk pairing gap, and there is a normal-topological phase transition driven by the temperature, which has not been discussed before. These results pave an effective way to realize the TSC and Majorana fermions in a large class of superconductors.

  5. Spectral distribution of Fe2+ photoionization cross section in InP:Fe

    International Nuclear Information System (INIS)

    Iikawa, F.

    1985-01-01

    Measurements of Fe 2+ ( 5 E) photoionization cross section in InP at 80 0 K, using constant current photoconductivity technique, were done. The spectrum presents a threshold energy of ∼ 0,65 eV due to the transition from Fe 2+ charge state, in the ground state, to Fe 3+ with an electron emission for the minimum conduction band. In the measurement of photoluminescence at ∼ 2 0 K, a wide emission of Fe complexe with the strong lattice interaction. In order to analyse the experimental data of Fe 2+ cross section in InP, a theoretical model was used. (M.C.K.) [pt

  6. Interstitial Fe in MgO

    CERN Document Server

    Mølholt, T E; Gunnlaugsson, H P; Svane, A; Masenda, H; Naidoo, D; Bharuth-Ram, K; Fanciulli, M; Gislason, H P; Johnston, K; Langouche, G; Ólafsson, S; Sielemann, R; Weyer, G

    2014-01-01

    Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

  7. Layered structure analysis of multilayers by X-ray reflectometry using the Cu-Kβ line

    International Nuclear Information System (INIS)

    Usami, Katsuhisa; Ueda, Kazuhiro; Hirano, Tatsumi; Hoshiya, Hiroyuki; Narishige, Shinji.

    1997-01-01

    The suitability of X-ray reflectometry using the Cu-K β line for layered structure analysis of NiFe/Cu/NiFe/Ta layered films was studied. Structural parameters such as film thickness, density, and interface width can be determined more accurately than by Cu-K α1 X-ray reflectometry, owing to the abnormal dispersion effect. The standard deviations in determination of film thicknesses were within ±0.3% for NiFe and Ta films and ±0.03 nm for 2 nm Cu film. Those for the densities and interface widths were within ±2% and ±0.04 nm for all films, respectively. Analysis of some layered films regarding the change in Cu film thickness showed that in all these samples the density of the films most closely reflected the density of bulk material, and the interface width between the upper NiFe and Cu films increased with increasing Cu film thickness. (author)

  8. Proteolytic cleavage orchestrates cofactor insertion and protein assembly in [NiFe]-hydrogenase biosynthesis.

    Science.gov (United States)

    Senger, Moritz; Stripp, Sven T; Soboh, Basem

    2017-07-14

    Metalloenzymes catalyze complex and essential processes, such as photosynthesis, respiration, and nitrogen fixation. For example, bacteria and archaea use [NiFe]-hydrogenases to catalyze the uptake and release of molecular hydrogen (H 2 ). [NiFe]-hydrogenases are redox enzymes composed of a large subunit that harbors a NiFe(CN) 2 CO metallo-center and a small subunit with three iron-sulfur clusters. The large subunit is synthesized with a C-terminal extension, cleaved off by a specific endopeptidase during maturation. The exact role of the C-terminal extension has remained elusive; however, cleavage takes place exclusively after assembly of the [NiFe]-cofactor and before large and small subunits form the catalytically active heterodimer. To unravel the functional role of the C-terminal extension, we used an enzymatic in vitro maturation assay that allows synthesizing functional [NiFe]-hydrogenase-2 of Escherichia coli from purified components. The maturation process included formation and insertion of the NiFe(CN) 2 CO cofactor into the large subunit, endoproteolytic cleavage of the C-terminal extension, and dimerization with the small subunit. Biochemical and spectroscopic analysis indicated that the C-terminal extension of the large subunit is essential for recognition by the maturation machinery. Only upon completion of cofactor insertion was removal of the C-terminal extension observed. Our results indicate that endoproteolytic cleavage is a central checkpoint in the maturation process. Here, cleavage temporally orchestrates cofactor insertion and protein assembly and ensures that only cofactor-containing protein can continue along the assembly line toward functional [NiFe]-hydrogenase. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. A method for determination of [Fe3+]/[Fe2+] ratio in superparamagnetic iron oxide

    Science.gov (United States)

    Jiang, Changzhao; Yang, Siyu; Gan, Neng; Pan, Hongchun; Liu, Hong

    2017-10-01

    Superparamagnetic iron oxide nanoparticles (SPION), as a kind of nanophase materials, are widely used in biomedical application, such as magnetic resonance imaging (MRI), drug delivery, and magnetic field assisted therapy. The magnetic property of SPION has close connection with its crystal structure, namely it is related to the ratio of Fe3+ and Fe2+ which form the SPION. So a simple way to determine the content of the Fe3+ and Fe2+ is important for researching the property of SPION. This review covers a method for determination of the Fe3+ and Fe2+ ratio in SPION by UV-vis spectrophotometry based the reaction of Fe2+ and 1,10-phenanthroline. The standard curve of Fe with R2 = 0.9999 is used for determination the content of Fe2+ and total iron with 2.5 mL 0.01% (w/v) SPION digested by HCl, pH = 4.30 HOAc-NaAc buffer 10 mL, 0.01% (w/v) 1,10-phenanthroline 5 mL and 10% (w/v) ascorbic acid 1 mL for total iron determine independently. But the presence of Fe3+ interfere with obtaining the actual value of Fe2+ (the error close to 9%). We designed a calibration curve to eliminate the error by devising a series of solution of different ratio of [Fe3+]/[Fe2+], and obtain the calibration curve. Through the calibration curve, the error between the measured value and the actual value can be reduced to 0.4%. The R2 of linearity of the method is 0.99441 and 0.99929 for Fe2+ and total iron respectively. The error of accuracy of recovery and precision of inter-day and intra-day are both lower than 2%, which can prove the reliability of the determination method.

  10. Oxygen abundance in metal-poor dwarfs, derived from the forbidden line

    Science.gov (United States)

    Spite, M.; Spite, F.

    1991-12-01

    The oxygen abundance is redetermined in a few metal-poor dwarfs, using the oxygen forbidden line at 630 nm rather than the oxygen triplet at 777 nm previously used by Abia and Rebolo (1989). The ratios form O/Fe are clearly lower than the previous ones and are in agreement with the ratios found in the metal-poor red giants, suggesting that no real difference exists between dwarfs and giants. Finally, it can be argued that, pending the acquisition of additional information, the oxygen abundances derived from the forbidden line are more reliable than the abundances found from the triplet.

  11. Electric quadrupole interaction in cubic BCC α-Fe

    International Nuclear Information System (INIS)

    Błachowski, A.; Komędera, K.; Ruebenbauer, K.; Cios, G.; Żukrowski, J.; Górnicki, R.

    2016-01-01

    Mössbauer transmission spectra for the 14.41-keV resonant line in "5"7Fe have been collected at room temperature by using "5"7Co(Rh) commercial source and α-Fe strain-free single crystal as an absorber. The absorber was magnetized to saturation in the absorber plane perpendicular to the γ-ray beam axis applying small external magnetic field. Spectra were collected for various orientations of the magnetizing field, the latter lying close to the [110] crystal plane. A positive electric quadrupole coupling constant was found practically independent on the field orientation. One obtains the following value V_z_z = +1.61(4) × 10"1"9 Vm"−"2 for the (average) principal component of the electric field gradient (EFG) tensor under assumption that the EFG tensor is axially symmetric and the principal axis is aligned with the magnetic hyperfine field acting on the "5"7Fe nucleus. The nuclear spectroscopic electric quadrupole moment for the first excited state of the "5"7Fe nucleus was adopted as +0.17 b. Similar measurement was performed at room temperature using as-rolled polycrystalline α-Fe foil of high purity in the zero external field. Corresponding value for the principal component of the EFG was found as V_z_z = +1.92(4) × 10"1"9 Vm"−"2. Hence, it seems that the origin of the EFG is primarily due to the local (atomic) electronic wave function distortion caused by the spin–orbit interaction between effective electronic spin S and incompletely quenched electronic angular momentum L. It seems as well that the lowest order term proportional to the product L·λ·S dominates, as no direction dependence of the EFG principal component is seen. The lowest order term is isotropic for a cubic symmetry as one has λ=λ 1 for cubic systems with the symbol 1 denoting unit operator and λ being the coupling parameter. - Highlights: • Precision of MS the same as MAPON • Real scans versus magnetization direction • A challenge for ab initio calculations

  12. Comparison in the electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8} insulator with YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Guan, X.Y. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Pan, M. [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Zhao, Y., E-mail: yzhao@home.swjtu.edu.cn [Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, Ministry of Education, Superconductivity R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

    2013-10-15

    Highlights: • The electronic structure of YBa{sub 2}Fe{sub 3}O{sub 8}, YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} were investigated by XPS. • The core-level and valence-band structures of these systems are different. • The density of states at Fermi level is related to the superconductivity. -- Abstract: The electronic structure and chemical states of relevant elements of YBa{sub 2}Fe{sub 3}O{sub 8} are investigated using X-ray photoemission spectroscopy (XPS), compared with those of YBa{sub 2}Cu{sub 3}O{sub 7} and SmFeAsO{sub 0.8}F{sub 0.2} superconductors. The typical differences and similarities in core-level and valence-band structures of these systems have been detected, strongly suggesting that the superconductivity have the finite density of states around Fermi level. Several features of O1s, Y3d, Ba3d, and Fe2p core lines in XPS spectra are also carefully compared and analyzed.

  13. Electric-field tunable perpendicular magnetic anisotropy in tetragonal Fe4N/BiFeO3 heterostructures

    Science.gov (United States)

    Yin, Li; Wang, Xiaocha; Mi, Wenbo

    2017-07-01

    Electric field control on perpendicular magnetic anisotropy (PMA) is indispensable for spintronic devices. Herewith, in tetragonal Fe4N/BiFeO3 heterostructures with the FeAFeB/Fe-O2 interface, PMA in each Fe4N layer, not merely interfacial layers, is modulated by the electric field, which is attributed to the broken spin screening of the electric field in highly spin-polarized Fe4N. Moreover, the periodical dx y+dy z+dz2 and dx y+dx2-y2 orbital-PMA oscillation enhances the interactions between adjacent FeAFeB and (FeB)2N atomic layers, which benefits the electric field modulation on PMA in the whole Fe4N atomic layers. The electric-field control on PMA in Fe4N/BiFeO3 heterostructures is favored by the electric-field-lifted potential in Fe4N.

  14. Magnetic nanowires (Fe, Fe-Co, Fe-Ni – magnetic moment reorientation in respect of wires composition

    Directory of Open Access Journals (Sweden)

    Kalska-Szostko Beata

    2015-03-01

    Full Text Available Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX, scanning electron microscopy (SEM, and X-ray diffraction (XRD, respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered or chemical composition (Co or Ni. The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS.

  15. Electron microscopy and diffraction of barium-lanthanum ferrites: Ba/sub x/La/sub 1-x/FeO/sub 3-y/

    Energy Technology Data Exchange (ETDEWEB)

    Parras, M.; Vallet-Regi, M.; Gonzalez-Calbet, J.M.; Alario-Franco, M.; Grenier, J.C.

    1988-05-01

    The system formed by Ba/sub 2/Fe/sub 2/O/sub 5/ and LaFeO/sub 3/ has been studied at the microstructural level. Four different phases, which are metrical multiples of the perovskite cubic cell, appear as a function of the Ba/La ratio. Their microstructure ranges from three-dimensional multitwinning, as in LaFeO/sub 3/, to an apparently stoichiometric line phase of Ba/sub 2/Fe/sub 2/O/sub 5/ composition with parameters a = 23.40(1) A, b = 11.71(1) A, c = 7.05(1) A, and ..beta.. = 98/sup 0/3(1)'. For 0 < x < 0.25, cubic regions appear within a LaFeO/sub 3/ matrix. When x = 0.33, a double perovskite cell is intergrown with a single one. Such a single cubic perovskite is the only phase obtained in the 0.33 < x < 0.66 range.

  16. Fe-Impregnated Mineral Colloids for Peroxide Activation: Effects of Mineral Substrate and Fe Precursor.

    Science.gov (United States)

    Li, Yue; Machala, Libor; Yan, Weile

    2016-02-02

    Heterogeneous iron species at the mineral/water interface are important catalysts for the generation of reactive oxygen species at circumneutral pH. One significant pathway leading to the formation of such species arises from deposition of dissolved iron onto mineral colloids due to changes in redox conditions. This study investigates the catalytic properties of Fe impregnated on silica, alumina, and titania nanoparticles (as prototypical mineral colloids). Fe impregnation was carried out by immersing the mineral nanoparticles in dilute Fe(II) or Fe(III) solutions at pH 6 and 3, respectively, in an aerobic environment. The uptake of iron per unit surface area follows the order of nTiO2 > nAl2O3 > nSiO2 for both types of Fe precursors. Impregnation of mineral particles in Fe(II) solutions results in predominantly Fe(III) species due to efficient surface-mediated oxidation. The catalytic activity of the impregnated solids to produce hydroxyl radical (·OH) from H2O2 decomposition was evaluated using benzoic acid as a probe compound under dark conditions. Invariably, the rates of benzoic acid oxidation with different Fe-laden particles increase with the surface density of Fe until a critical density above which the catalytic activity approaches a plateau, suggesting active Fe species are formed predominantly at low surface loadings. The critical surface density of Fe varies with the mineral substrate as well as the aqueous Fe precursor. Fe impregnated on TiO2 exhibits markedly higher activity than its Al2O3 and SiO2 counterparts. The speciation of interfacial Fe is analyzed with diffuse reflectance UV-vis analysis and interpretation of the data in the context of benzoic oxidation rates suggests that the surface activity of the solids for ·OH generation correlates strongly with the isolated (i.e., mononuclear) Fe species. Therefore, iron dispersed on mineral colloids is a significant form of reactive iron surfaces in the aquatic environment.

  17. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  18. High-frequency permeability of electroplated CoNiFe and CoNiFe-C alloys

    International Nuclear Information System (INIS)

    Rhen, Fernando M.F.; McCloskey, Paul; O'Donnell, Terence; Roy, Saibal

    2008-01-01

    We have investigated CoNiFe and CoNiFe-C electrodeposited by pulse reverse plating (PRP) and direct current (DC) techniques. CoNiFe(PRP) films with composition Co 59.4 Fe 27.7 Ni 12.8 show coercivity of 95 A m -1 (1.2 Oe) and magnetization saturation flux (μ 0 M s ) of 1.8 T. Resistivity of CoNiFe (PRP) is about 24 μΩ cm and permeability remains almost constant μ r ' ∼475 up to 30 MHz with a quality factor (Q) larger than 10. Additionally, the permeability spectra analysis shows that CoNiFe exhibits a classical eddy current loss at zero bias field and ferromagnetic resonance (FMR) when biased with 0.05 T. Furthermore, a crossover between eddy current and FMR loss is observed for CoNiFe-PRP when baised with 0.05 T. DC and PRP plated CoNiFe-C, which have resistivity and permeability of 85, 38 μΩ cm, μ r '=165 and 35 with Q>10 up to 320 MHz, respectively, showed only ferromagnetic resonance losses. The ferromagnetic resonance peaks in CoNiFe and CoNiFe-C are broad and resembles a Gaussian distribution of FMR frequencies. The incorporation of C to CoNiFe reduces eddy current loss, but also reduces the FMR frequency

  19. NifI inhibits nitrogenase by competing with Fe protein for binding to the MoFe protein

    International Nuclear Information System (INIS)

    Dodsworth, Jeremy A.; Leigh, John A.

    2007-01-01

    Reduction of substrate by nitrogenase requires direct electron transfer from the Fe protein to the MoFe protein. Inhibition of nitrogenase activity in Methanococcus maripaludis occurs when the regulatory protein NifI 1,2 binds the MoFe protein. This inhibition is relieved by 2-oxoglutarate. Here we present evidence that NifI 1,2 binding prevents association of the two nitrogenase components. Increasing amounts of Fe protein competed with NifI 1,2 , decreasing its inhibitory effect. NifI 1,2 prevented the co-purification of MoFe protein with a mutant form of the Fe protein that forms a stable complex with the MoFe protein, and NifI 1,2 was unable to bind to an AlF 4 - -stabilized Fe protein:MoFe protein complex. NifI 1,2 inhibited ATP- and MoFe protein-dependent oxidation of the Fe protein, and 2OG relieved this inhibition. These results support a model where NifI 1,2 competes with the Fe protein for binding to MoFe protein and prevents electron transfer

  20. Local moments and electronic correlations in Fe-based Heusler alloys: Kα x-ray emission spectra measurements

    International Nuclear Information System (INIS)

    Svyazhin, Artem; Kurmaev, Ernst; Shreder, Elena; Shamin, Sergey; Sahle, Christoph J.

    2016-01-01

    Heusler alloys are a property-rich class of materials, intensively investigated today from both theoretical and real-world application points of view. In this paper, we attempt to shed light on the role of electronic correlations in the Fe_2MeAl group (where Me represents all 3d elements from Ti to Ni) of Heusler alloys. For this purpose, we have investigated the local moments of iron by means of the x-ray emission spectroscopy technique. To obtain numerical values of local moments, the Kα-FWHM method has been employed for the first time. In every compound of the group, the presence of a local moment on the Fe atom was detected. As has been revealed, the values of these moments are temperature-independent, pointing to an insufficiency of a pure itinerant approach to magnetism in these alloys. We also comprehensively compare the usage of Kβ main lines and Kα spectra as tools for the probing of local moments and point out the significant advantages of the latter. - Highlights: • Local spin moments of iron in Fe_2MeAl (Me = Ti … Ni) Heusler alloys were investigated by means of x-ray emission spectroscopy. • Independence of the local moments from temperature confirms their localized nature. • A local moment value of iron in Fe_2MeAl raises with the atomic number of element Me. • The applicability of the Kα x-ray emission line for extracting local moment values of 3d elements was established.

  1. Na7 [Fe2S6 ] , Na2 [FeS2 ] and Na2 [FeSe2 ] : New 'reduced' sodium chalcogenido ferrates

    Science.gov (United States)

    Stüble, Pirmin; Peschke, Simon; Johrendt, Dirk; Röhr, Caroline

    2018-02-01

    Three new 'reduced' FeII containing sodium chalcogenido ferrates were obtained applying a reductive synthetic route. The mixed-valent sulfido ferrate Na7 [Fe2S6 ] , which forms bar-shaped crystals with metallic greenish luster, was synthesized in pure phase from natural pyrite and elemental sodium at a maximum temperature of 800 °C. Its centrosymmetric triclinic structure (SG P 1 bar , a = 764.15(2), b = 1153.70(2), c = 1272.58(3) pm, α = 62.3325 (7) , β = 72.8345 (8) , γ = 84.6394 (8) ° , Z = 3, R1 = 0.0185) exhibits two crystallographically different [Fe2S6 ] 7 - dimers of edge-sharing [FeS4 ] tetrahedra, with somewhat larger Fe-S distances than in the fully oxidized FeIII dimers of e.g. Na6 [Fe2III S6 ] . In contrast to the localized AFM ordered pure di-ferrates(III), the Curie-Weiss behavior of the magnetic susceptibility proves the rarely observed valence-delocalized S = 9/2 state of the mixed-valent FeIII /FeII dimer. The nearly spin-only value of the magnetic moment combined with the chemical bonding not generally differing from that in pure ferrates(II) and (III), provides a striking argument, that the reduction of the local Fe spin moments observed in all condensed sulfido ferrate moieties is connected with the AFM spin ordering. The two isotypic ferrates(II) Na2 [FeS2 ] and Na2 [FeSe2 ] with chain-like structural units (SG Ibam, a = 643.54(8)/ 660.81(1), b = 1140.2(2)/1190.30(2) c = 562.90(6)/585.59(1) pm, Z = 4, R1 = 0.0372/0.0466) crystallize in the K2 [ZnO2 ] -type structure. Although representing merely further members of the common series of chalcogenido metallates(II) Na2 [MIIQ2 ] , these two new phases, together with Na6 [FeS4 ] and Li2 [FeS2 ] , are the only examples of pure FeII alkali chalcogenido ferrates. The new compounds allow for a general comparison of di- and chain ferrates(II) and (III) and mixed-valent analogs concerning the electronic and magnetic properties (including Heisenberg super-exchange and double-exchange interactions

  2. Structural and magnetic properties of Ce/Fe and Ce/FeCoV multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tixier, S; Boeni, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Mannix, D; Stirling, W G [Liverpool Univ. (United Kingdom); Lander, G H

    1997-09-01

    Ce/Fe and Ce/FeCoV multilayers have been grown by magnetron sputtering. The interfaces are well defined and the layers are crystalline down to an individual layer thickness of 20 A. Ce/FeCoV multilayers show sharper interfaces than Ce/Fe but some loss of crystallinity is observed. Hysteresis loops obtained by SQUID show different behaviour of the bulk magnetisation as a function of the layer thickness. Fe moments are found by Moessbauer spectroscopy to be perpendicular to the interfaces for multilayers with small periodicity. (author) 2 figs., 2 refs.

  3. Electronic Properties of LiFePO4 and Li doped LiFePO4

    International Nuclear Information System (INIS)

    Zhuang, G.V.; Allen, J.L.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

    2005-01-01

    The potential use of different iron phosphates as cathode materials in lithium-ion batteries has recently been investigated.1 One of the promising candidates is LiFePO4. This compound has several advantages in comparison to the state-of-the-art cathode material in commercial rechargeable lithium batteries. Firstly, it has a high theoretical capacity (170 mAh/g). Secondly, it occurs as mineral triphylite in nature and is inexpensive, thermally stable, non-toxic and non-hygroscopic. However, its low electronic conductivity (∼10-9 S/cm) results in low power capability. There has been intense worldwide research activity to find methods to increase the electronic conductivity of LiFePO4, including supervalent ion doping,2 introducing non-carbonaceous network conduction3 and carbon coating, and the optimization of the carbon coating on LiFePO4 particle surfaces.4 Recently, the Li doped LiFePO4 (Li1+xFe1-xPO4) synthesized at ARL has yield electronic conductivity increase up to 106.5 We studied electronic structure of LiFePO4 and Li doped LiFePO4 by synchrotron based soft X-ray emission (XES) and X-ray absorption (XAS) spectroscopies. XAS probes the unoccupied partial density of states, while XES the occupied partial density of states. By combining XAS and XES measurements, we obtained information on band gap and orbital character of both LiFePO4 and Li doped LiFePO4. The occupied and unoccupied oxygen partial density of states (DOS) of LiFePO4 and 5 percent Li doped LiFePO4 are presented in Fig. 1. Our experimental results clearly indicate that LiFePO4 has wideband gap (∼ 4 eV). This value is much larger than what is predicted by DFT calculation. For 5 percent Li doped LiFePO4, a new doping state was created closer to the Fermi level, imparting p-type conductivity, consistent with thermopower measurement. Such observation substantiates the suggestion that high electronic conductivity in Li1.05Fe0.95 PO4 is due to available number of charge carriers in the material

  4. Effect of the oxidation rate and Fe(II) state on microbial nitrate-dependent Fe(III) mineral formation

    Science.gov (United States)

    Senko, John M.; Dewers , Thomas A.; Krumholz, Lee R.

    2005-01-01

    A nitrate-dependent Fe(II)-oxidizing bacterium was isolated and used to evaluate whether Fe(II) chemical form or oxidation rate had an effect on the mineralogy of biogenic Fe(III) (hydr)oxides resulting from nitrate-dependent Fe(II) oxidation. The isolate (designated FW33AN) had 99% 16S rRNA sequence similarity to Klebsiella oxytoca. FW33AN produced Fe(III) (hydr)oxides by oxidation of soluble Fe(II) [Fe(II)sol] or FeS under nitrate-reducing conditions. Based on X-ray diffraction (XRD) analysis, Fe(III) (hydr)oxide produced by oxidation of FeS was shown to be amorphous, while oxidation of Fe(II)sol yielded goethite. The rate of Fe(II) oxidation was then manipulated by incubating various cell concentrations of FW33AN with Fe(II)sol and nitrate. Characterization of products revealed that as Fe(II) oxidation rates slowed, a stronger goethite signal was observed by XRD and a larger proportion of Fe(III) was in the crystalline fraction. Since the mineralogy of Fe(III) (hydr)oxides may control the extent of subsequent Fe(III) reduction, the variables we identify here may have an effect on the biogeochemical cycling of Fe in anoxic ecosystems.

  5. Magnetic properties of FeZr{sub 2} and Fe{sub 2}Zr intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Prajapat, C. L., E-mail: prajapat@barc.gov.in; Singh, M. R.; Mishra, P. K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Chattaraj, D. [Product Development Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Mishra, R. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Ravikumar, G. [Scientific Information Resources Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India)

    2016-05-23

    Magnetic properties of Fe-Zr system, viz., FeZr{sub 2} and Fe{sub 2}Zr have been studied. Both the compounds show soft ferromagnetic behavior. Curie temperature is well above the room temperature. Lower saturation magnetization for the zirconium rich sample, FeZr{sub 2}, could be due to possible donation of electrons from the Zr-rich neighbors to Fe atoms or diminution of long range magnetic order by defects.

  6. Synthesis and characterization of polypropiolate sodium (PPNa)-Fe3O4 nanocomposite

    International Nuclear Information System (INIS)

    Bahceci, S.; Unal, B.; Baykal, A.; Soezeri, H.; Karaoglu, E.; Esat, B.

    2011-01-01

    Highlights: · Polypropiolate sodium (PPNa)-Fe 3 O 4 nanocomposite was successfully synthesized by reflux route. · FT-IR, TGA and TEM analyses showed that the presence of PPNa onto the surface of Fe 3 O 4 NP's. · Magnetization measurements revealed that (PPNa)-Fe 3 O 4 nanocomposite has superparamagnetic properties at room temperature. · Magnetic core size, particle size and crystallite size are coinciding with each other. · It is pointed out that the a.c. conductivity of the nanocomposite studied here obeys the well-known power law of frequency in which it also varies with temperatures. - Abstract: Polypropiolate sodium (PPNa)-Fe 3 O 4 nanocomposites were successfully synthesized by the precipitation of Fe 3 O 4 in the presence of sodium polypropiolate and followed by reflux route. Structural, morphological, electrical and magnetic properties evaluation of the nanocomposite were performed by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), vibrating scanning magnetometry (VSM) and conductivity measurements. Crystalline phase was identified as magnetite with an average crystallite size of 7 ± 3 nm as estimated from X-ray line profile fitting. Particle size estimated from TEM, by log-normal fitting, is ∼9 ± 1 nm. FT-IR analysis shows that the binding of PPNa on the surface of iron oxide is through bidentate linkage of carboxyl group. TGA analysis showed the presence of 20% PPNa around 80% magnetic core (Fe 3 O 4 )...PPNa-Fe 3 O 4 nanocomposite show superparamagnetic characteristics at room temperature. It is found that the a.c. conductivity of the nanocomposites obeys the well-known power law of frequency in which it also depends on temperature. Additionally, its d.c. conductivity showed that two operating regions of the activation energy. Both real and imaginary parts of either permittivity exhibit almost the same attitudes which are the indication of

  7. Removal of FePO4 and Fe3(PO4)2 crystals on the surface of passive fillers in Fe0/GAC reactor using the acclimated bacteria

    International Nuclear Information System (INIS)

    Lai, Bo; Zhou, Yuexi; Yang, Ping; Wang, Juling; Yang, Jinghui; Li, Huiqiang

    2012-01-01

    Highlights: ► Fe 3 (PO 4 ) 2 and FePO 4 crystals would weaken treatment efficiency of Fe 0 /GAC reactor. ► Fe 3 (PO 4 ) 2 and FePO 4 crystals could be removed by the acclimated bacteria. ► FeS and sulfur in the passive film would be removed by the sulfur-oxidizing bacteria. ► Develop a cost-effective bio-regeneration technology for the passive fillers. - Abstract: As past studies presented, there is obvious defect that the fillers in the Fe 0 /GAC reactor begin to be passive after about 60 d continuous running, although the complicated, toxic and refractory ABS resin wastewater can be pretreated efficiently by the Fe 0 /GAC reactor. During the process, the Fe 3 (PO 4 ) 2 and FePO 4 crystals with high density in the passive film are formed by the reaction between PO 4 3− and Fe 2+ /Fe 3+ . Meanwhile, they obstruct the formation of macroscopic galvanic cells between Fe 0 and GAC, which will lower the wastewater treatment efficiency of Fe 0 /GAC reactor. In this study, in order to remove the Fe 3 (PO 4 ) 2 and FePO 4 crystals on the surface of the passive fillers, the bacteria were acclimated in the passive Fe 0 /GAC reactor. According to the results, it can be concluded that the Fe 3 (PO 4 ) 2 and FePO 4 crystals with high density in the passive film could be decomposed or removed by the joint action between the typical propionic acid type fermentation bacteria and sulfate reducing bacteria (SRB), whereas the PO 4 3− ions from the decomposition of the Fe 3 (PO 4 ) 2 and FePO 4 crystals were released into aqueous solution which would be discharged from the passive Fe 0 /GAC reactor. Furthermore, the remained FeS and sulfur (S) in the passive film also can be decomposed or removed easily by the oxidation of the sulfur-oxidizing bacteria. This study provides some theoretical references for the further study of a cost-effective bio-regeneration technology to solve the passive problems of the fillers in the zero-valent iron (ZVI) or Fe 0 /GAC reactor.

  8. On the maximal operators of Riesz logarithmic means of Vilenkin-Fourier series

    OpenAIRE

    Tephnadze, George

    2014-01-01

    Comment: Vilenkin system, Riesz logarithmic means, martingale Hardy space. arXiv admin note: text overlap with arXiv:1410.6101, arXiv:1410.6416, arXiv:1410.7204, arXiv:1410.7635, arXiv:1410.6186, arXiv:1410.7075, arXiv:1410.6102

  9. The Abundances of the Fe Group Elements in AV 304, an Abundance Standard in the Small Magellanic Cloud

    Science.gov (United States)

    Peters, Geraldine J.; Lanz, Thierry; Bouret, Jean-Claude; Proffitt, Charles R.; Adelman, Saul J.; Hubeny, Ivan

    2018-06-01

    AV 304 is a B0.5 IV field star in the Small Magellanic Cloud with ultra-sharp spectral lines that has emerged as an abundance standard. We have combined recent spectroscopic observations from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope with archival data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and ESO’s VLT/UVES to determine the abundances of the Fe group elements (Ti, V, Cr, Mn, Fe, Co, & Ni). The analysis was carried through using the Hubeny/Lanz NLTE programs TLUSTY/SYNSPEC. The COS observations were secured with the G130M, G160M, G185M, and G225M gratings. Combined with the FUSE data, we have achieved spectral coverage in the UV from 950 to 2400 A. Measurable lines from the Fe group, except for a very few multiplets of Fe II, III are not observed in optical spectra. The following stellar parameters were found: Teff = 27500±500 K, log g = 3.7±0.1 cm/s2, Vturb= 1±1 km/s, and v sin i = 8 ±2 km/s. The Fe abundance appears to be only slightly lower than the mean depletion in the SMC, but the other Fe group elements are underabundant by 0.3 dex or more. This study confirmed the low abundance of nitrogen (-1.25 dex relative to the solar value) that was reported by Peters & Adelman (ASP Conf. Series, 348, p. 136, 2006). Whereas the light elements are delivered to the ISM by core-collapse supernovae (CCSNe), the Fe group elements are believed to come mostly from low/intermediate mass binaries containing white dwarfs that undergo SNe Ia explosions. A single SNe Ia can deliver 0.5 solar masses of pure Fe (and maybe Mn) to the ISM compared with about 0.07 solar masses from a CCSNe. It appears that there is very little processed material from its interior in the atmosphere of AV 304 and that the star did not form from an interstellar cloud that was enriched by material from earlier supernova activity. Support from STScI grants HST-GO-14081.002 and HST-GO-13346.022, and USC’s Women in Science and Engineering (WiSE) program is

  10. Optimization of Fe2+ supplement in anaerobic digestion accounting for the Fe-bioavailability.

    Science.gov (United States)

    Cai, Yafan; Zhao, Xiaoling; Zhao, Yubin; Wang, Hongliang; Yuan, Xufeng; Zhu, Wanbin; Cui, Zongjun; Wang, Xiaofen

    2018-02-01

    Fe is widely used as an additive in anaerobic digestion, but its bioavailability and the mechanism by which it enhances digestion are unclear. In this study, sequential extraction was used to measure Fe bioavailability, while biochemical parameters, kinetics model and Q-PCR (fluorescence quantitative PCR) were used to explore its mechanism of stimulation. The results showed that sequential extraction is a suitable method to assess the anaerobic system bioavailability of Fe, which is low and fluctuates to a limited extent (1.7 to -3.1wt%), indicating that it would be easy for Fe levels to be insufficient. Methane yield increased when the added Fe 2+ was 10-500mg/L. Appropriate amounts of Fe 2+ accelerated the decomposition of rice straw and facilitated methanogen metabolism, thereby improving reactor performance. The modified Gompertz model better fitted the results than the first-order kinetic model. Feasibility analysis showed that addition of Fe 2+ at ≤50mg/L was suitable. Copyright © 2017. Published by Elsevier Ltd.

  11. Chemical consequences of the nuclear reactions 58Fe(n,γ)59Fe and 57Co(EC)57Fe in soluble Prussian Blue

    DEFF Research Database (Denmark)

    Fenger, Jes; Maddock, A. G.; Siekierska, K. E.

    1970-01-01

    KFe[Fe(CN)6],H2O was prepared with 58Fe in either the cation or the complex, and both samples were neutron-irradiated and analysed for free and complexed 59Fe. Parallel experiments were performed on K4[Fe(CN)6],3H2O. In Prussian Blue the retention in the hexacyano-complex is ca. 5% and can be inc...

  12. A non-local thermodynamical equilibrium line formation for neutral and singly ionized titanium in model atmospheres of reference A-K stars

    Science.gov (United States)

    Sitnova, T. M.; Mashonkina, L. I.; Ryabchikova, T. A.

    2016-09-01

    We construct a model atom for Ti I-II using more than 3600 measured and predicted energy levels of Ti I and 1800 energy levels of Ti II, and quantum mechanical photoionization cross-sections. Non-local thermodynamical equilibrium (NLTE) line formation for Ti I and Ti II is treated through a wide range of spectral types from A to K, including metal-poor stars with [Fe/H] down to -2.6 dex. NLTE leads to weakened Ti I lines and positive abundance corrections. The magnitude of NLTE corrections is smaller compared to the literature data for FGK atmospheres. NLTE leads to strengthened Ti II lines and negative NLTE abundance corrections. For the first time, we have performed NLTE calculations for Ti I-II in the 6500 ≤ Teff ≤ 13 000 K range. For four A-type stars, we derived in LTE an abundance discrepancy of up to 0.22 dex between Ti I and Ti II, which vanishes in NLTE. For four other A-B stars, with only Ti II lines observed, NLTE leads to a decrease of line-to-line scatter. An efficiency of inelastic Ti I + H I collisions was estimated from an analysis of Ti I and Ti II lines in 17 cool stars with -2.6 ≤ [Fe/H] ≤ 0.0. Consistent NLTE abundances from Ti I and Ti II were obtained by applying classical Drawinian rates for the stars with log g ≥ 4.1, and neglecting inelastic collisions with H I for the very metal-poor (VMP) giant HD 122563. For the VMP turn-off stars ([Fe/H] ≤ -2 and log g ≤ 4.1), we obtained the positive abundance difference Ti I-II already in LTE, which increases in NLTE. Accurate collisional data for Ti I and Ti II are necessary to help solve this problem.

  13. Numerical Methods for Plate Forming by Line Heating

    DEFF Research Database (Denmark)

    Clausen, Henrik Bisgaard

    2000-01-01

    Line heating is the process of forming originally flat plates into a desired shape by means of heat treatment. Parameter studies are carried out on a finite element model to provide knowledge of how the process behaves with varying heating conditions. For verification purposes, experiments are ca...... are carried out; one set of experiments investigates the actual heat flux distribution from a gas torch and another verifies the validty of the FE calculations. Finally, a method to predict the heating pattern is described....

  14. Perpendicular exchange coupling effects in ferrimagnetic TbFeCo/GdFeCo hard/soft structures

    Science.gov (United States)

    Wang, Ke; Wang, Yahong; Ling, Fujin; Xu, Zhan

    2018-04-01

    Bilayers consisting of magnetically hard TbFeCo and soft GdFeCo alloy were fabricated. Exchange-spring and sharp switching in a step-by-step fashion were observed in the TbFeCo/GdFeCo hard/soft bilayers with increasing GdFeCo thickness. A perpendicular exchange bias field of several hundred Oersteds is observed from the shift of minor loops pinned by TbFeCo layer. The perpendicular exchange energy is derived to be in the range of 0.18-0.30 erg/cm2. The exchange energy is shown to increase with the thickness of GdFeCo layer in the bilayers, which can be attributed to the enhanced perpendicular anisotropy of GdFeCo layer in our experimental range.

  15. Preparation and characterization of Fe3O4@Au-C225 composite targeted nanoparticles for MRI of human glioma.

    Science.gov (United States)

    Ge, Yaoqi; Zhong, Yuejiao; Ji, Guozhong; Lu, Qianling; Dai, Xinyu; Guo, Zhirui; Zhang, Peng; Peng, Gang; Zhang, Kangzhen; Li, Yuntao

    2018-01-01

    To study the characterization of Fe3O4@Au-C225 composite targeted MNPs. Fe3O4@Au-C225 was prepared by the absorption method. The immunosorbent assay was used to evaluate its absorption efficiency at C225 Fc. ZETA SIZER3000 laser particle size analyzer, ultraviolet photometer and its characteristics were analyzed by VSM. the targeting effect of Fe3O4@Au-C225 composite targeted MNPs on U251 cells in vitro were detected by 7.0 Tesla Micro-MR; and subcutaneous transplanted human glioma in nude mice were performed the targeting effect in vivo after tail vein injection of Fe3O4@Au-C225 composite targeted MNPs by MRI. The self-prepared Fe3O4@Au composite MNPs can adsorb C225 with high efficiency of adsorption so that Fe3O4@Au-C225 composite targeted MNPs were prepared successfully. Fe3O4@Au-C225 composite targeted MNPs favorably targeted human glioma cell line U251 in vitro; Fe3O4@Au-C225 composite targeted MNPs have good targeting ability to xenografted glioma on nude mice in vivo, and can be traced by MRI. The Fe3O4@Au-C225 composite targeted MNPs have the potential to be used as a tracer for glioma in vivo.

  16. Exchange-coupled Fe3O4/CoFe2O4 nanoparticles for advanced magnetic hyperthermia

    Science.gov (United States)

    Glassell, M.; Robles, J.; Das, R.; Phan, M. H.; Srikanth, H.

    Iron oxide nanoparticles especially Fe3O4, γ-Fe2O3 have been extensively studied for magnetic hyperthermia because of their tunable magnetic properties and stable suspension in superparamagnetic regime. However, their relatively low heating capacity hindered practical application. Recently, a large improvement in heating efficiency has been reported in exchange-coupled nanoparticles with exchange coupling between soft and hard magnetic phases. Here, we systematically studied the effect of core and shell size on the heating efficiency of the Fe3O4/CoFe2O4 core/shell nanoparticles. The nanoparticles were synthesized using thermal decomposition of organometallic precursors. Transmission electron microscopy (TEM) showed formation of spherical shaped Fe3O4 and Fe3O-/CoFe2O4 nanoparticles. Magnetic measurements showed high magnetization (≅70 emu/g) and superparamagnetic behavior for the nanoparticles at room temperature. Magnetic hyperthermia results showed a large increase in specific absorption rate (SAR) for 8nm Fe3O4/CoFe2O4 compared to Fe3O4 nanoparticles of the same size. The heating efficiency of the Fe3O4/CoFe2O4 with 1 nm CoFe2O4 (shell) increased from 207 to 220 W/g (for 800 Oe) with increase in core size from 6 to 8 nm. The heating efficiency of the Fe3O4/CoFe2O4 with 2 nm CoFe2O4 (shell) and core size of 8 nm increased from 220 to 460 W/g (for 800 Oe). These exchange-coupled Fe3O4/CoFe2O4 core/shell nanoparticles can be a good candidate for advanced hyperthermia application.

  17. [{sup 18}F]FE-SUPPY and [{sup 18}F]FE-SUPPY:2 - metabolic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Haeusler, Daniela [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Nics, Lukas [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Nutritional Sciences, Univ. of Vienna, A-1090 Vienna (Austria); Mien, Leonhard-Key [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Ungersboeck, Johanna [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Inorganic Chemistry, Univ. of Vienna, A-1090 Vienna (Austria); Lanzenberger, Rupert R. [Dept. of Psychiatry and Psychotherapy, Medical Univ. of Vienna, A-1090 Vienna (Austria); Shanab, Karem [Dept. of Drug and Natural Product Synthesis, Univ. of Vienna, A-1090 Vienna (Austria); Sindelar, Karoline M. [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Viernstein, Helmut [Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Wagner, Karl-Heinz [Dept. of Nutritional Sciences, Univ. of Vienna, A-1090 Vienna (Austria); Dudczak, Robert; Kletter, Kurt [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Wadsak, Wolfgang [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Inorganic Chemistry, Univ. of Vienna, A-1090 Vienna (Austria); Mitterhauser, Markus [Dept. of Nuclear Medicine, Medical Univ. of Vienna, A-1090 Vienna (Austria); Dept. of Pharmaceutical Technology and Biopharmaceutics, Univ. of Vienna, A-1090 Vienna (Austria); Hospital Pharmacy of the General Hospital of Vienna, A-1090 Vienna (Austria)], E-mail: markus.mitterhauser@meduniwien.ac.at

    2010-05-15

    Introduction: Recently, [{sup 18}F]FE-SUPPY and [{sup 18}F]FE-SUPPY:2 were introduced as the first positron emission tomography (PET) tracers for the adenosine A{sub 3} receptor. Thus, aim of the present study was the metabolic characterization of the two adenosine A{sub 3} receptor PET tracers. Methods: In vitro carboxylesterase (CES) experiments were conducted using incubation mixtures containing different concentrations of the two substrates, porcine CES and phosphate-buffered saline. Enzymatic reactions were stopped by adding acetonitrile/methanol (10:1) after various time points and analyzed by a high-performance liquid chromatography (HPLC) standard protocol. In vivo experiments were conducted in male wild-type rats; tracers were injected through a tail vein. Rats were sacrificed after various time points (n=3), and blood and brain samples were collected. Sample cleanup was performed by an HPLC standard protocol. Results: The rate of enzymatic hydrolysis by CES demonstrated Michaelis-Menten constants in a micromolar range (FE-SUPPY, 20.15 {mu}M, and FE-SUPPY:2, 13.11 {mu}M) and limiting velocities of 0.035 and 0.015 {mu}M/min for FE-SUPPY and FE-SUPPY:2, respectively. Degree of metabolism in blood showed the following: 15 min pi 47.7% of [{sup 18}F]FE-SUPPY was intact compared to 33.1% of [{sup 18}F]FE-SUPPY:2; 30 min pi 30.3% intact [{sup 18}F]FE-SUPPY was found compared to 15.6% [{sup 18}F]FE-SUPPY:2. In brain, [{sup 18}F]FE-SUPPY:2 formed an early hydrophilic metabolite, whereas metabolism of [{sup 18}F]FE-SUPPY was not observed before 30 min pi Conclusion: Knowing that metabolism in rats is several times faster than in human, we conclude that [{sup 18}F]FE-SUPPY should be stable for the typical time span of a clinical investigation. As a consequence, from a metabolic point of view, one would tend to decide in favor of [{sup 18}F]FE-SUPPY.

  18. A new high-pressure phase of Fe2SiO4 and the relationship between spin and structural transitions

    Science.gov (United States)

    Yamanaka, T.; Kyono, A.; Nakamoto, Y.; Kharlamova, S. A.; Struzhkin, V. V.; Gramsch, S.; Mao, H.; Hemley, R. J.

    2013-12-01

    Structure transformation of Fe2SiO4 Angle-dispersive powder x-ray diffraction was carried out at beam line 16-BMD APS. Structure of a new high-pressure phase of I-Fe2SiO4 spinel was determined by Rietveld profile fitting of x-ray diffraction data up to 64GPa at ambient temperature. A structural transition from the cubic spinel to the new structure was observed at 34GPa. Diffraction patterns taken at 44.6GPa and 54.6GPa indicate a two-phase mixture of spinel and new high-pressure phase. Reversible transition from I-Fe2SiO4 to spinel was confirmed. Laser heating experiment at 1500K proved the decomposition of Fe2SiO4 spinel to two oxides of FeO and SiO2. Spin transition X-ray emission measurements of Fe2SiO4 were carried out up to 65GPa at ambient temperature at beam line 16-IDD APS. The spin transition exerts an influence to Fe2SiO4 spinel structure and triggers two distinct curves of the lattice constant in the spinel phase. Although the compression curve of the spinel is discontinuous at approximately 20 GPa, Fe Kβ emission measurements show that the transition from a high spin (HS) to an intermediate spin (IS) state begins at 17GPa in the spinel phase. The IS electronic state is gradually enhanced with pressure, which results in an isostructural phase transition. HS-to-LS transition of iron bearing spinels starts from 15.6GPa in Fe3O4 and 19.6GPa in Fe2TiO4. The transition is more capable due to Fe2+ in the octahedral site. The extremely shortened octahedral bonds result in a distortion of 6-fold cation site. New structure of Fe2SiO4 Monte Carlo method was applied to find candidates for the high-pressure phase using the diffraction intensities with fixed lattice constants determined by DICVOL. Rietveld profile fitting was then performed using the initial model. The new structure is a body centered orthorhombic phase (I-Fe2SiO4) with space group Imma and Z=4, with two crystallographically distinct FeO6 octahedra. Silicon exists in six-fold coordination in I-Fe2Si

  19. Fe biomineralization mirrors individual metabolic activity in a nitrate-dependent Fe(II-oxidizer

    Directory of Open Access Journals (Sweden)

    Jennyfer eMIOT

    2015-09-01

    Full Text Available Microbial biomineralization sometimes leads to periplasmic encrustation, which is predicted to enhance microorganism preservation in the fossil record. Mineral precipitation within the periplasm is however thought to induce death, as a result of permeability loss preventing nutrient and waste transit across the cell wall. This hypothesis had however never been investigated down to the single cell level. Here, we cultured the nitrate reducing Fe(II oxidizing bacteria Acidovorax sp. strain BoFeN1 that have been previously shown to promote the precipitation of a diversity of Fe minerals (lepidocrocite, goethite, Fe phosphate encrusting the periplasm. We investigated the connection of Fe biomineralization with carbon assimilation at the single cell level, using a combination of electron microscopy and Nano-Secondary Ion Mass Spectrometry (NanoSIMS. Our analyses revealed strong individual heterogeneities of Fe biomineralization. Noteworthy, a small proportion of cells remaining free of any precipitate persisted even at advanced stages of biomineralization. Using pulse chase experiments with 13C-acetate, we provide evidences of individual phenotypic heterogeneities of carbon assimilation, correlated with the level of Fe biomineralization. Whereas non- and moderately encrusted cells were able to assimilate acetate, higher levels of periplasm encrustation prevented any carbon incorporation. Carbon assimilation only depended on the level of Fe encrustation and not on the nature of Fe minerals precipitated in the cell wall. Carbon assimilation decreased exponentially with increasing cell-associated Fe content. Persistence of a small proportion of non-mineralized and metabolically active cells might constitute a strategy of survival in highly ferruginous environments. Eventually, our results suggest that periplasmic Fe biomineralization may provide a signature of individual metabolic status, which could be looked for in the fossil record and in modern

  20. Cysteine as a ligand platform in the biosynthesis of the FeFe hydrogenase H cluster.

    Science.gov (United States)

    Suess, Daniel L M; Bürstel, Ingmar; De La Paz, Liliana; Kuchenreuther, Jon M; Pham, Cindy C; Cramer, Stephen P; Swartz, James R; Britt, R David

    2015-09-15

    Hydrogenases catalyze the redox interconversion of protons and H2, an important reaction for a number of metabolic processes and for solar fuel production. In FeFe hydrogenases, catalysis occurs at the H cluster, a metallocofactor comprising a [4Fe-4S]H subcluster coupled to a [2Fe]H subcluster bound by CO, CN(-), and azadithiolate ligands. The [2Fe]H subcluster is assembled by the maturases HydE, HydF, and HydG. HydG is a member of the radical S-adenosyl-L-methionine family of enzymes that transforms Fe and L-tyrosine into an [Fe(CO)2(CN)] synthon that is incorporated into the H cluster. Although it is thought that the site of synthon formation in HydG is the "dangler" Fe of a [5Fe] cluster, many mechanistic aspects of this chemistry remain unresolved including the full ligand set of the synthon, how the dangler Fe initially binds to HydG, and how the synthon is released at the end of the reaction. To address these questions, we herein show that L-cysteine (Cys) binds the auxiliary [4Fe-4S] cluster of HydG and further chelates the dangler Fe. We also demonstrate that a [4Fe-4S]aux[CN] species is generated during HydG catalysis, a process that entails the loss of Cys and the [Fe(CO)2(CN)] fragment; on this basis, we suggest that Cys likely completes the coordination sphere of the synthon. Thus, through spectroscopic analysis of HydG before and after the synthon is formed, we conclude that Cys serves as the ligand platform on which the synthon is built and plays a role in both Fe(2+) binding and synthon release.

  1. Magnetic defects in KTaO{sub 3} and KTaO{sub 3}:Fe nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Golovina, Iryna; Shanina, Bela; Kolesnik, Sergiy [Institute of Semiconductor Physics of NAS of Ukraine, pr. Nauki 41, 03028 Kyiv (Ukraine); Geifman, Ilia [Quality Engineering Education, Buffalo Grove, IL 60089 (United States); Andriiko, Alexander [National Technical University of Ukraine ' ' KPI' ' , 03056 Kyiv (Ukraine)

    2012-11-15

    Magnetic defects in non-doped and iron-doped nanopowders of KTaO{sub 3} were studied by resonance and static magnetic measurements. The resonance spectra and hysteresis loops of KTaO{sub 3}:Fe nanocrystalline powders were observed and investigated for the first time. Unlike bulk crystals, both non-doped and doped nanopowders exhibit two types of resonance lines, paramagnetic ones from the isolated Fe{sup 3+} ions and a ferromagnetic signal from ions involved in clusters. Theoretical description and full identification of the electron paramagnetic resonance (EPR) spectra were made. It was established that low doping (up to 0.4 mol%) increases the number of paramagnetic Fe{sup 3+} centers with axial and rhombic symmetries, and has no effect on the centers with cubic symmetry and magnetic clusters. Analysis of the temperature dependence of the spectra showed that the cluster's resonance line follows the Bloch law ''T{sup 3/2}'', which indicates a ferromagnetic nature of the cluster. A partial collapse of the ferromagnetic subsystem in the temperature range of 100-400 K was also found. Magnetization and other characteristics of ferromagnetic and paramagnetic subsystems were determined. An average cluster size was estimated to be equal to a length of 6.2 nm and the fractional volume of the ferromagnetic cluster system was found. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. NEAR-INFRARED SPECTROSCOPY OF NEARBY SEYFERT GALAXIES: IS THERE EVIDENCE FOR SHOCK EXCITATION IN NARROW-LINE REGIONS?

    Energy Technology Data Exchange (ETDEWEB)

    Terao, K. [Graduate School of Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Nagao, T.; Toba, Y. [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Hashimoto, T. [National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan (China); Yanagisawa, K. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Honjo 3037-5, Kamogata-cho, Asaguchi, Okayama 719-0232 (Japan); Matsuoka, K. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Ikeda, H. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 (Japan); Taniguchi, Y., E-mail: terao@cosmos.phys.sci.ehime-u.ac.jp [The Open University of Japan, Wakaba 2-11, Mihama-ku, Chiba 261-8586 (Japan)

    2016-12-20

    One of the important unsettled problems regarding active galactic nuclei (AGNs) is the major ionization mechanism of gas clouds in AGN narrow-line regions (NLRs). In order to investigate this issue, we present our J -band spectroscopic observations of a sample of 26 nearby Seyfert galaxies. In our study, we use the flux ratio of the following two forbidden emission lines, [Fe ii]1.257  μ m and [P ii]1.188  μ m, because it is known that this ratio is sensitive to the ionization mechanism. We obtain the [Fe ii]/[P ii] flux ratio or its lower limit for 19 objects. In addition to our data, we compile this flux ratio (or its lower limit) for 23 nearby Seyfert galaxies from the literature. Based on the collected data, we find that three Seyfert galaxies show very large lower limits of the [Fe ii]/[P ii] flux ratios (≳10): NGC 2782, NGC 5005, and Mrk 463. It is thus suggested that the contribution of the fast shock in the gas excitation is significantly large for them. However, more than half of the Seyfert galaxies in our sample show moderate [Fe ii]/[P ii] flux ratios (∼2), which is consistent with pure photoionization by power-law ionizing continuum emission. We also find that the [Fe ii]/[P ii] flux ratio shows no clear correlation with the radio loudness, suggesting that the radio jet is not the primary origin of shocks in NLRs of Seyfert galaxies.

  3. Short-range order of amorphous FeNiB alloy after neutron irradiation

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.; Baluch, S.; Cirak, J.; Lipka, J.

    1990-01-01

    Transmission Moessbauer spectroscopy was used to study irradiation-induced changes in the short-range order of an amorphous Fe 80-x Ni x B 20 alloy. Neutron irradiation led to an increase of the width of a hyperfine field distribution implying atomic rearrangement towards disordering. Changes in a mean value of a HFD and Moessbauer line areas can be associated with a reorientation of spins due to radiation damage. (orig.)

  4. Resonant Ni and Fe KLL Auger spectra photoexcited from NiFe alloys

    International Nuclear Information System (INIS)

    Koever, L.; Cserny, I.; Berenyi, Z.; Egri, S.; Novak, M.

    2005-01-01

    Complete text of publication follows. KLL Auger spectra of 3d transition metal atoms in solid environment, measured using high energy resolution, give an insight into the details of the local electronic structure surrounding the particular atoms emitting the signal Auger electrons. Fine tuning the energy of the exciting monochromatic photons across the K-absorption edge, features characteristic to resonant phenomena can be identified in the spectra. The shapes of the resonantly photoexcited KLL Auger spectra induced from 3d transition metals and alloys are well interpreted by the single step model of the Auger process, based on the resonant scattering theory. The peak shapes are strongly influenced by the 4p partial density of unoccupied electronic states around the excited atom. High energy resolution studies of KLL Auger spectra of 3d transition metals using laboratory X-ray sources, however, request very demanding experiments and yield spectra of limited statistical quality making the evaluation of the fine details in the spectra difficult. The Tunable High Energy XPS (THE- XPS) instrument at BW2 offers optimum photon x and energy resolution for spectroscopy of deep core Auger transitions. For the present measurements high purity polycrystalline Ni and Fe sheets as well as NiFe alloy samples of different compositions (Ni 80 Fe 20 , Ni 50 Fe 50 , Ni 20 Fe 80 ) were used. The surfaces of the samples were cleaned by in-situ argon ion sputtering. The measurements of the Ni and Fe KL 23 L 23 Auger spectra of the metal and alloy samples were performed with the THE-XPS instrument using high electron energy resolution (0.2 eV). In Fig.1, the measured Fe KL 23 L 23 spectrum, photoexcited at the Fe K absorption edge from Fe metal, is compared with the respective spectrum excited from a Ni 50 Fe 50 alloy. A significant broadening of the 1 D 2 peak and an enhancement of the spectral intensity at the low energy loss part of this peak observed in the alloy sample, while the

  5. Microstructure, Texture, and Mechanical Behavior of As-cast Ni-Fe-W Matrix Alloy

    Science.gov (United States)

    Rao, A. Sambasiva; Manda, Premkumar; Mohan, M. K.; Nandy, T. K.; Singh, A. K.

    2018-04-01

    This article describes the tensile properties, flow, and work-hardening behavior of an experimental alloy 53Ni-29Fe-18W in as-cast condition. The microstructure of the alloy 53Ni-29Fe-18W displays single phase (fcc) in as-cast condition along with typical dendritic features. The bulk texture of the as-cast alloy reveals the triclinic sample symmetry and characteristic nature of coarse-grained materials. The alloy exhibits maximum strength ( σ YS and σ UTS) values along the transverse direction. The elongation values are maximum and minimum along the transverse and longitudinal directions, respectively. Tensile fracture surfaces of both the longitudinal and transverse samples display complete ductile fracture features. Two types of slip lines, namely, planar and intersecting, are observed in deformed specimens and the density of slip lines increases with increasing the amount of deformation. The alloy displays moderate in-plane anisotropy ( A IP) and reasonably low anisotropic index ( δ) values, respectively. The instantaneous or work-hardening rate curves portray three typical stages (I through III) along both the longitudinal and transverse directions. The alloy exhibits dislocation-controlled strain hardening during tensile testing, and slip is the predominant deformation mechanism.

  6. Electrical resistivity surface for FeO-Fe2O3-P2O5 glasses

    Science.gov (United States)

    Vaughan, J. G.; Kinser, D. L.

    1975-01-01

    The dc electrical properties and microstructure of x(FeO-Fe2O3)-(100-x)P2O5 glasses were investigated up to a maximum of x = 75 mol %. Results indicate that, in general, the minimum resistivity of the glass does not occur at equal Fe(2+) and Fe(3+) concentrations, although for the special case where x = 55 mol % the minimum does occur at Fe(2+)/Fe total = 0.5, as reported by other investigators. Evidence presented shows that the position of the minimum resistivity is a function of total iron content. The minimum shifts to glasses richer in Fe(2+) at higher total iron concentrations.

  7. Synthesis and characterization of bracelet-like magnetic nanorings consisting of Ag-Fe3O4 bi-component nanoparticles.

    Science.gov (United States)

    Zhou, Shuai; Chen, Qianwang

    2011-09-14

    Stable bracelet-like magnetic nanorings, formed by Ag-Fe(3)O(4) nanoparticles with an average size around 40 nm, have been successfully prepared in large scale by means of reducing Ag(+) and Fe(3+) simultaneously under mild conditions. In the reaction, tiny grains of silver are used as seeds to prompt small Fe(3)O(4) nanoparticles to grow larger, which is essential to enhance the magnetic dipole-dipole interactions, while only superparamagnetic Fe(3)O(4) nanoparticles (about 10 nm in size) can be obtained in the absence of Ag seeds. The XRD, TEM, SAED and the EDS line scan data reveal that these nanoparticles are in the core-shell structure. These magnetic Ag-Fe(3)O(4) nanoparticles assembled into nanorings by magnetic dipole-dipole interactions with a diameter of 100-200 nm. The saturation magnetization of the nanorings is 39.5 emu g(-1) at room temperature. The MRI images indicate that these kind of nanorings have the potential application in diagnostics as a T(2) MRI contrast agent. This journal is © The Royal Society of Chemistry 2011

  8. Role of PO4 tetrahedron in LiFePO4 and FePO4 system.

    Science.gov (United States)

    Zeng, Yuewu

    2015-06-01

    Using high resolution transmission electron microscopy with image simulation and Fourier analysis, the Li1- x FePO4 (x < 0.01), Li1- x FePO4 (x ∼ 0.5), and FePO4 particles, prepared by charging or discharging the 053048 electrochemical cells (thickness: 5 mm, width: 30 mm, height: 48 mm) and dismantled inside an Ar-filled dry box, were investigated. The high resolution images reveal: (1) the solid solution of Li1- x FePO4 (x < 0.01) contains some missing Li ions leading PO4 group distorted around M1 tunnel of the unit cell; (2) the texture of the particles of Li1- x FePO4 (x ∼0.5) has homogeneously distributed compositional domains of LiFePO4 and FePO4 resulting from spinodal decomposition which promote Li ion easily getting into the particle due to uphill diffusion, (3) the particles of FePO4 formed in charging have heavily distorted lattice and contain some isolated LiFePO4 , (4) interface between LiFePO4 and FePO4 and between amorphous and crystal region provides the lattice distortion of small polarons. © 2015 Wiley Periodicals, Inc.

  9. A New Test of Copper and Zinc Abundances in Late-type Stars Using Ultraviolet Cu II and Zn II Lines

    Science.gov (United States)

    Roederer, Ian U.; Barklem, Paul S.

    2018-04-01

    We present new abundances derived from Cu I, Cu II, Zn I, and Zn II lines in six warm (5766 ≤ {T}eff} ≤ 6427 K), metal-poor (‑2.50 ≤ [Fe/H] ≤ ‑0.95) dwarf and subgiant (3.64 ≤ log g ≤ 4.44) stars. These abundances are derived from archival high-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and ground-based optical spectra from several observatories. Ionized Cu and Zn are the majority species, and abundances derived from Cu II and Zn II lines should be largely insensitive to departures from local thermodynamic equilibrium (LTE). We find good agreement between the [Zn/H] ratios derived separately from Zn I and Zn II lines, suggesting that departures from LTE are, at most, minimal (≲0.1 dex). We find that the [Cu/H] ratios derived from Cu II lines are 0.36 ± 0.06 dex larger than those derived from Cu I lines in the most metal-poor stars ([Fe/H] McDonald Observatory of the University of Texas at Austin.

  10. Electric-field effects on magnetic anisotropy in Pd/Fe/Pd(0 0 1) surface

    International Nuclear Information System (INIS)

    Haraguchi, Shinya; Tsujikawa, Masahito; Gotou, Junpei; Oda, Tatsuki

    2011-01-01

    Electric-field (EF) effects have been studied on magnetic anisotropy in the metallic surfaces Pt/Fe/Pt(0 0 1) and Pd/Fe/Pd(0 0 1) by means of the first-principles electronic structure calculation which employs the generalized gradient approximation. The variation of anisotropy energy with respect to the EF is found to be opposite to each other. The modulus rate of the variation is larger by a few factors in the Pt substrate than in the Pd one. These results agree qualitatively well with the available experimental data. The electronic structures are presented and the origins in EF effects are discussed along a line of the second perturbative fashion.

  11. Microstructure, magnetic and Moessbauer studies on spark-plasma sintered Sm-Co-Fe/Fe(Co) nanocomposite magnets

    Energy Technology Data Exchange (ETDEWEB)

    Rao, N V Rama; Saravanan, P; Gopalan, R; Raja, M Manivel; Rao, D V Sreedhara; Chandrasekaran, V [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India); Sivaprahasam, D [International Advanced Research Centre for Powder Metallurgy and New Materials Hyderabad-500 005 (India); Ranganathan, R [Saha Institute of Nuclear Physics, Kolkata-700 064 (India)], E-mail: rg_gopy@yahoo.com

    2008-03-21

    Nanocomposite powders comprising Sm-Co-Fe intermetallic phases and Fe(Co) were synthesized by high-energy ball milling and were consolidated into bulk magnets by the spark-plasma sintering (SPS) technique. While the microstructure of the SPS samples was characterized by transmission electron microscopy (TEM), the solubility of Fe in different phases was investigated using Moessbauer spectroscopy. TEM studies revealed that the spark-plasma sintered sample has Sm(Co,Fe){sub 5} as a major phase with Sm{sub 2}(Co,Fe){sub 17}, Sm(Co,Fe){sub 2} and Fe(Co) as secondary phases. The size of the nanocrystalline grains of all these phases was found to be in the range 50-100 nm. The Moessbauer spectra of the as-milled powders exhibited two different subspectra: a sextet corresponding to the Fe phase and a broad sextet associated with the Fe(Co) phase; while that of the SPS sample showed four different subspectra: a sextet corresponding to Fe and other three sextets corresponding to the Fe(Co), Sm(Co,Fe){sub 5} and Sm{sub 2}(Co,Fe){sub 17} phases; these results are in accordance with the TEM observation. Recoil magnetization and reversible susceptibility measurements revealed magnetically single phase behaviour of the SPS magnets.

  12. Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

    Energy Technology Data Exchange (ETDEWEB)

    Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

    2016-03-15

    Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

  13. Combined Effects of Fe3O4 Nanoparticles and Chemotherapeutic Agents on Prostate Cancer Cells In Vitro

    Directory of Open Access Journals (Sweden)

    Kanako Kojima

    2018-01-01

    Full Text Available Patients with metastatic castration-resistant prostate cancer (mCRPC have poor outcomes. Docetaxel (DTX-based therapy is a current standard treatment for patients with mCRPC. Approaches combining conventional chemotherapeutic agents and nanoparticles (NPs, particularly iron oxide NPs, may overcome the serious side effects and drug resistance, resulting in the establishment of new therapeutic strategies. We previously reported the combined effects of Fe3O4 nanoparticles (Fe3O4 NPs with DTX on prostate cancer cells in vitro. In this study, we investigated the combined effects of Fe3O4 NPs and rapamycin or carboplatin on prostate cancer cells in vitro. Treatment of DU145 and PC-3 cells with Fe3O4 NPs increased intracellular reactive oxygen species (ROS levels in a concentration-dependent manner. Treatment of both cell lines with 100 μg/mL Fe3O4 NPs for 72 h resulted in significant inhibition of cell viability with a different inhibitory effect. Combination treatments with 100 µg/mL Fe3O4 NPs and 10 µM carboplatin or 10 nM rapamycin in DU145 and PC-3 cells significantly decreased cell viability. Synergistic effects on apoptosis were observed in PC-3 cells treated with Fe3O4 NPs and rapamycin and in DU145 cells with Fe3O4 NPs and carboplatin. These results suggest the possibility of combination therapy with Fe3O4 NPs and various chemotherapeutic agents as a novel therapeutic strategy for patients with mCRPC.

  14. Fe/V and Fe/Co (0 0 1) superlattices: growth, anisotropy, magnetisation and magnetoresistance

    International Nuclear Information System (INIS)

    Nordblad, P.; Broddefalk, A.; Mathieu, R.; Blomqvist, P.; Eriksson, O.; Waeppling, R.

    2003-01-01

    Some physical properties of BCC Fe/V and Fe/Co (0 0 1) superlattices are reviewed. The dependence of the magnetic anisotropy on the in-plane strain introduced by the lattice mismatch between Fe and V is measured and compared to a theoretical derivation. The dependence of the magnetic anisotropy (and saturation magnetisation) on the layer thickness ratio Fe/Co is measured and a value for the anisotropy of BCC Co is derived from extrapolation. The interlayer exchange coupling of Fe/V superlattices is studied as a function of the V layer thickness (constant Fe thickness) and layer thickness of Fe (constant V thickness). A region of antiferromagnetic coupling and GMR is found for V thicknesses 12-14 monolayers. However, surprisingly, a 'cutoff' of the antiferromagnetic coupling and GMR is found when the iron layer thickness exceeds about 10 monolayers

  15. The 1.5 Ms Observing Campaign on IRAS 13224-3809: X-ray Spectral Analysis I.

    Science.gov (United States)

    Jiang, J.; Parker, M. L.; Fabian, A. C.; Alston, W. N.; Buisson, D. J. K.; Cackett, E. M.; Chiang, C.-Y.; Dauser, T.; Gallo, L. C.; García, J. A.; Harrison, F. A.; Lohfink, A. M.; De Marco, B.; Kara, E.; Miller, J. M.; Miniutti, G.; Pinto, C.; Walton, D. J.; Wilkins, D. R.

    2018-03-01

    We present a detailed spectral analysis of the recent 1.5 Ms XMM-Newton observing campaign on the narrow line Seyfert 1 galaxy IRAS 13224-3809, taken simultaneously with 500 ks of NuSTAR data. The X-ray lightcurve shows three flux peaks, registering at about 100 times the minimum flux seen during the campaign, and rapid variability with a time scale of kiloseconds. The spectra are well fit with a primary powerlaw continuum, two relativistic-blurred reflection components from the inner accretion disk with very high iron abundance, and a simple blackbody-shaped model for the remaining soft excess. The spectral variability is dominated by the power law continuum from a corona region within a few gravitational radii from the black hole. Additionally, blueshifted Ne X, Mg XII, Si XIV and S XVI absorption lines are identified in the stacked low-flux spectrum, confirming the presence of a highly ionized outflow with velocity up to v = 0.263 and 0.229 c. We fit the absorption features with xstar models and find a relatively constant velocity outflow through the whole observation. Finally, we replace the bbody and supersolar abundance reflection models by fitting the soft excess successfully with the extended reflection model relxillD, which allows for higher densities than the standard relxill model. This returns a disk electron density ne > 1018.7 cm-3 and lowers the iron abundance from Z_Fe=24^{+3}_{-4}Z_⊙ with ne ≡ 1015 cm-3 to Z_Fe=6.6^{+0.8}_{-2.1}Z_⊙.

  16. Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems.

    Science.gov (United States)

    Sowers, Tyler D; Adhikari, Dinesh; Wang, Jian; Yang, Yu; Sparks, Donald L

    2018-05-25

    Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high coassociation with OC in soils containing high Fe content, increase OC sorption extent to poorly crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation. We performed STXM-NEXAFS analysis on 2-line ferrihydrite reacted with leaf litter-extractable dissolved OC and citric acid in the absence and presence of Ca. Organic carbon was found to highly associate with Ca ( R 2 = 0.91). Carboxylic acid moieties were dominantly sequestered; however, Ca facilitated the additional sequestration of aromatic and phenolic moieties. Also, C NEXAFS revealed polyvalent metal ion complexation. Our results provide evidence for the presence of Fe-Ca-OC ternary complexation, which has the potential to significantly impact how organo-mineral associations are modeled.

  17. Fe/Ni thin films temperature investigation with MgO and SiO2 interfaces by ferromagnetic resonance

    International Nuclear Information System (INIS)

    Zyubin, A; Orlova, A; Astashonok, A; Kupriyanova, G; Nevolin, V

    2011-01-01

    In this work the temperature study of magnetic – resonance properties of the structures such as Fe/MgO/Ni, Fe/SiO2/Ni differing thickness of spacer and of method of preparation was carried out by FMR. These systems are investigated to estimate their applicability in model creation experiments for a spintronics devices research [1–4]. The special attention was given to the temperature dependence research of three layer films linewidths. The out-of-plane temperature dependences of FMR signal position and line widths have been measured for Fe/Ni samples with MgO and Si/SiO2 interfaces in static position of 0 and 90 degrees rotation angle to the external static magnetic field. The extracted magnetic parameters such as linewidths and resonance field position were studied.

  18. Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Adam D.; Dopita, Michael A.; Davies, Rebecca; Hampton, Elise; Kewley, Lisa; Banfield, Julie; Groves, Brent; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Sairam, Lalitha [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Kharb, Preeti [National Centre for Radio Astrophysics—Tata Institute of Fundamental Research, Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007 (India); Scharwächter, Julia [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii 96720 (United States); Shalima, P. [Regional Institute of Education, Manasagangotri, Mysore 570006 (India); Sundar, M. N. [Jain University, 3rd Block Jayanagar, Bengaluru 560011 (India); Zaw, Ingyin, E-mail: adam.thomas@anu.edu.au [New York University (Abu Dhabi), 70 Washington Sq. S, New York, NY 10012 (United States)

    2017-09-01

    We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3 m telescope to obtain spectra with a spectral resolution of R  = 7000 in the red (540–700 nm) and R  = 3000 in the blue (350–570 nm), over an integral field of 25 × 38 arcsec{sup 2} with 1 × 1 arcsec{sup 2} spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities, and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe vii] λ 6087 is shown to be correlated with [O iii]/H β . Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.

  19. High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

    Directory of Open Access Journals (Sweden)

    Anabil Gayen

    2013-01-01

    Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

  20. Line Evolution of the Nova V5587 Sgr from Early to Nebula Phase

    Directory of Open Access Journals (Sweden)

    T. Kajikawa

    2015-02-01

    Full Text Available The spectral evolution of the nova V5587 Sgr has been monitored at Koyama Astronomical Observatory and Higashi-Hiroshima Observatory, Japan, from the early to nebula phase. The nova rebrightened several times. The spectra during the early phase showed emission lines of H α, H β, O I, He I, He II, N II, Fe II. Nova V5587 Sgr is classified into the Fe II type. The helium abundance of the nova is estimated as N(He/N(H = 0.134 ± 0.09. The light curve, the spectral evolution, and the helium abundance in V5587 Sgr are similar to those of the nova PW Vul.