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Bucknell C Webb - One of the best experts on this subject based on the ideXlab platform.
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magnetic and structural characterization of sputtered Fen multilayer films
Journal of Magnetism and Magnetic Materials, 1992Co-Authors: Michael A Russak, Christopher V Jahnes, E Klokholm, Mark E Re, Bucknell C WebbAbstract:The magnetic and structural properties of ferromagnetic Fen thin films. Fen/Fen (ferromagnetic/paramagnetic) and Fen/SiO2 multilayers deposited in a rotational dc magnetron sputter system were investigated. Monolithic films containing ⋍ 2at% N2had 4πMs, values ⋍ 25 kG magnetostriction (λs) has been related to N2 content and film thickness. λs could be varied significantly over a range of compositions where 4πMs was > 22 kG by adjusting thickness and nitrogen. content. Lamination reduced easy- and hard-axis coercivity to < Oe. Lorentz microscopy indicated that the ferromagnetic Fen layers in the Fen/Fen films were exchanged coupled while those in the Fen/SiO2 films were magnetostatically coupled.
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magnetic and structural characterization of sputtered Fen multilayer films
Journal of Applied Physics, 1991Co-Authors: Michael A Russak, Christopher V Jahnes, E Klokholm, Mark E Re, Bucknell C WebbAbstract:The magnetic and structural properties of ferromagnetic Fen thin films, Fen/Fen (ferromagnetic/paramagnetic), and Fen/SiO2 multilayers deposited in a rotational dc magnetron sputter system were investigated. Monolithic films containing ≂2 at. % N2 had 4πMs values ≂25 kG. The Fe16N2 phase has been identified by electron microdiffraction in these films. Saturation magnetostriction (λs) has been related to N2 content and can be varied from −3×10−6 to 5×10−6 in a range of compositions where 4πMs is ≳22 kG. Lamination reduced easy and hard axis coercivity to <1 Oe and produced single domain configurations in yoke‐shaped structures. Lorentz microscopy indicated that the ferromagnetic Fen layers in the Fen/Fen films were exchanged coupled while those in the Fen/SiO2 films were magnetostatically coupled.
Michael R Lieber - One of the best experts on this subject based on the ideXlab platform.
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the Fen 1 family of structure specific nucleases in eukaryotic dna replication recombination and repair
BioEssays, 1997Co-Authors: Michael R LieberAbstract:Unlike the most well-characterized prokaryotic polymerase, E. Coli DNA pol I, none of the eukaryotic polymerases have their own 5′ to 3′ exonuclease domain for nick translation and Okazaki fragment processing. In eukaryotes, Fen-1 is an endo-and exonuclease that carries out this function independently of the polymerase molecules. Only seven nucleases have been cloned from multicellular eukaryotic cells. Among these, Fen-1 is intriguing because it has complex structural preferences; specifically, it cleaves at branched DNA structures. The cloning of Fen-1 permitted establishment of the first eukaryotic nuclease family, predicting that S. cerevisiae RAD2 (S. pombe Rad13) and its mammalian homolog, XPG, would have similar structural specficity. The Fen-1 nuclease family includes several similar enzymes encoded by bacteriophages. The crystal structures of two enzymes in the Fen-1 nuclease family have been solved and they provide a structural basis for the interesting steric requirements of Fen-1 substrates. Because of their unique structural specificities, Fen-1 and its family members have important roles in DNA replication, repair and, potentially, recombination. Recently, Fen-1 was found to specifically associate with PCNA, explaining some aspects of Fen-1 function during DNA replication and potentially in DNA repair.
Michael A Russak - One of the best experts on this subject based on the ideXlab platform.
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magnetic and structural characterization of sputtered Fen multilayer films
Journal of Magnetism and Magnetic Materials, 1992Co-Authors: Michael A Russak, Christopher V Jahnes, E Klokholm, Mark E Re, Bucknell C WebbAbstract:The magnetic and structural properties of ferromagnetic Fen thin films. Fen/Fen (ferromagnetic/paramagnetic) and Fen/SiO2 multilayers deposited in a rotational dc magnetron sputter system were investigated. Monolithic films containing ⋍ 2at% N2had 4πMs, values ⋍ 25 kG magnetostriction (λs) has been related to N2 content and film thickness. λs could be varied significantly over a range of compositions where 4πMs was > 22 kG by adjusting thickness and nitrogen. content. Lamination reduced easy- and hard-axis coercivity to < Oe. Lorentz microscopy indicated that the ferromagnetic Fen layers in the Fen/Fen films were exchanged coupled while those in the Fen/SiO2 films were magnetostatically coupled.
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magnetic and structural characterization of sputtered Fen multilayer films
Journal of Applied Physics, 1991Co-Authors: Michael A Russak, Christopher V Jahnes, E Klokholm, Mark E Re, Bucknell C WebbAbstract:The magnetic and structural properties of ferromagnetic Fen thin films, Fen/Fen (ferromagnetic/paramagnetic), and Fen/SiO2 multilayers deposited in a rotational dc magnetron sputter system were investigated. Monolithic films containing ≂2 at. % N2 had 4πMs values ≂25 kG. The Fe16N2 phase has been identified by electron microdiffraction in these films. Saturation magnetostriction (λs) has been related to N2 content and can be varied from −3×10−6 to 5×10−6 in a range of compositions where 4πMs is ≳22 kG. Lamination reduced easy and hard axis coercivity to <1 Oe and produced single domain configurations in yoke‐shaped structures. Lorentz microscopy indicated that the ferromagnetic Fen layers in the Fen/Fen films were exchanged coupled while those in the Fen/SiO2 films were magnetostatically coupled.
H Fujimori - One of the best experts on this subject based on the ideXlab platform.
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crystal structure and magnetic properties of the compound Fen
Journal of Alloys and Compounds, 1993Co-Authors: K Suzuki, H Morita, T Kaneko, H Yoshida, H FujimoriAbstract:Abstract The compound Fen was prepared as a single phase by d.c. reactive sputtering. Its crystal structure was determined by X-ray diffraction measurements to be the zinc blende type f.c.c. structure. This compound Fen is stable up to 593 K and decomposes into Fen+Fe2N above 593 K. The present sample exhibits a micromagnetic character at low temperatures, which is considered to be related to the antiferromagnetism of the Fen compound.
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Soft Magnetic Properties of Fen/FeBN Multi-layers
IEEE Translation Journal on Magnetics in Japan, 1992Co-Authors: S. Ohnuma, H Fujimori, F. Matsumoto, T. MasumotoAbstract:stract-The magnetic and structural properties of multilayered Fen/FeBN films prepared by dual-target sputtering were investigated. Laminating FeBN films with Fen films increases the electrical resistivity (R) by up to 200 μΩ-cm, decreases slightly the saturation magnetization and results in excellent soft magnetic properties (coercivity ≤0.2 Oe and permeability ≥1000) over a wide range of film thickness combinations; this despite the fact that single FeBN films have a high R of about 400 μΩ-cm, a Bs of about 12 kG and semi-hard magnetic properties with perpendicular magnetic anisotropy. SEM observations suggest that the soft magnetic properties of Fen/FeBN multilayer films originate in their in-plane anisotropy and the fine grain texture of the films. Despite film thicknesses exceeding 2 μm, a permeability of about 1000 was maintained even near 100 MHz. The extended frequency response of the permeability is without doubt due to the increased electrical resistivity of films when laminated with FeBN.
César Pulgarín - One of the best experts on this subject based on the ideXlab platform.
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principal parameters affecting virus inactivation by the solar photo Fenton process at neutral ph and μm concentrations of h2o2 and fe2 3
Applied Catalysis B-environmental, 2015Co-Authors: E Ortegagomez, Anna Carratala, Fernandez P Ibanez, M Ballesteros M Martin, J Sanchez A Perez, César PulgarínAbstract:The inactivation of the coliphage MS2 (a human virus indicator) by solar photo-Fenton at near neutral pH in carbonate buffer solution matrix was evaluated. The effects of reactant concentration (H2O2, Fe2+, Fe3+) and solar irradiance on the photo-Fenton process were studied. Specifically, the solar exposure/Fe3+ treatment showed a strong dependence on the iron concentration and solar irradiance intensity leading to complete inactivation (from 10(6) PFU mL(-1) to the detection limit) with 1 mg L-1 of Fe3+ and 60 min of solar irradiance (45 W m(-2)). The MS2 inactivation observed with the photo-Fenton process (solar exposure/H2O2/Fe2+/3+) carried out with Fe3+, was faster than with Fe2+ (detection limit achieved at 20 min and 50 min, respectively). Moreover, virus inactivation by photo-Fenton under different solar irradiance values (15,30 and 45 W m(-2)), H2O2 and Fe3+ concentrations (0.1, 0.5 and I mg L-1) and different pH values (6, 7 and 8) were evaluated. In order to validate the efficiency of the photo-Fenton process at near neutral pH on virus inactivation, the photocatalytic treatment was carried out in natural water (Lake Geneva, Switzerland) and with a human virus (Echovirus). Finally, a conceptual mechanistic interpretation was proposed regarding how solar photo-Fenton acts on viruses in water, involving the key species Fe2+, Fe3+, H2O2, solar irradiance, organic matter, and their possible reactions and interactions. (C) 2015 Elsevier B.V. All rights reserved.
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The effect of Fe2+, Fe3+, H2O2 and the photo-Fenton reagent at near neutral pH on the solar disinfection (SODIS) at low temperatures of water containing Escherichia coli K12
Applied Catalysis B: Environmental, 2010Co-Authors: Dorothee Spuhler, Julian Andr??s Rengifo-herrera, Julián Andrés Rengifo-herrera, César PulgarínAbstract:The effect of Fe2+, Fe3+, H2O2 and the photo-Fenton system (Fe2+ or 3+/H2O2/hv) on solar water disinfection (SODIS) at low temperature and at near neutral pH are discussed in detail. We focus on Escherichia coli K12 suspended in either MilliQ water, water containing mineral ions and in MilliQ water enriched with resorcinol, a model for natural organic matter (NOM). Recently, the photo-Fenton reagent at near neutral pH and at millimolar concentrations (0.6 mg-1 Fe2+ or 3+ and 10 mg L-1 H2O2), was demonstrated to be highly efficient not only for the acceleration of solar disinfection of river water, but also for the elimination of NOM, which is a known precursor for halogenated disinfection byproducts. In this work, these effects were systematically assessed at laboratory scale and in well controlled conditions excluding thermal inactivation. Besides the highly bactericidal properties of the photo-Fenton system at near neutral pH, a bactericidal effect of Fe2+ alone and of Fe3+ under irradiation (Fe3+/hv) were also observed. This was associated with diffusion and intracellular dark Fenton reactions for Fe2+, while the effect of Fe3+/hv was attributed to the adsorption of Fe3+ on the bacterial cell wall and subsequent photosensitization of these iron-bacteria exciplexes, leading to the direct oxidation of the cell membrane and the generation of ROS close to the target microorganism. In MilliQ water, photo-inactivation rates for E. coli were increased by 200% in the presence of Fe2+/hv compared to the basic SODIS system (hv) and up to 250% in the presence of Fe2+/H2O2/hv. When Fe3+ was added, photo-inactivation was enhanced up to 135% for Fe3+/hv and 145% for Fe3+/H2O2/hv. Inorganic ions contained in mineral water did generally inhibit the beneficial effect of Fe2+ or 3+ and H2O2 on bacterial inactivation. In contrast, the systems containing model NOM (resorcinol in MilliQ water, corresponding to 30 mg TOC L-1) resulted in a higher iron-photo-assisted bacterial inactivation. This was associated with the formation of Fe3+-organo bounds, which are stable at near neutral pH and undergo photosensitization under solar radiation leading to the generation of ROS and the oxidation of the organic compounds. Photo-inactivation in the presence of the photo-Fenton reagent was enhanced up to 320% for Fe2+/H2O2/hv and 355% for Fe3+/H2O2/hv, with a simultaneous mineralization of 90% TOC within 4 h. Based on these experimental results and supported by literature, a mechanistic interpretation of iron-catalyzed solar water disinfection is proposed, which illustrates the possible pathways involved in photo-inactivation of E. coli in the presence of Fe2+, Fe3+ and H2O2. ?? 2010 Elsevier B.V. All rights reserved.