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Sample records for br cu fe

  1. The Amounts of As, Au, Br, Cu, Fe, Mo, Se and Zn in Normal and Uraemic Human whole Blood. A. Comparison by Means of Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Quantitative determination of the elements As, Au, Br, Cu, Fe, Mo, Se and Zn have been performed in normal and uraemic human whole blood by means of H2SO4 - H-O- digestion, distillation and ion exchange, combined with gamma-spectrometric analysis. The uraemic blood was found to contain about 10 times as much As and twice as much Mo as did the normal blood. As regards Fe, the uraemic blood contained slightly less than the normal blood. For the other elements there were no detectable difference

  2. Preparation and characterization of poly(glycidyl methacrylate)-grafted magnetic nanoparticles: Effects of the precursor concentration on polyol synthesis of Fe3O4 and [PMDETA]0/[CuBr2]0 ratios on SI-AGET ATRP

    Science.gov (United States)

    Jiang, Liping; Zhou, Xuyang; Wei, Guyun; Lu, Xiaoduo; Wei, Weiping; Qiu, Jianhua

    2015-12-01

    Polymer brushes based on poly(glycidyl methacrylate) (PGMA) have been successfully grafted from the surface of silica coated iron oxide (Fe3O4@SiO2) nanoparticles via surface-initiated activators generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The size of the nanoparticles could be adjusted from 7.3 to 9.6 nm by varying the precursor concentration of iron(III) acetylacetonate. The Fe3O4 nanoparticles possessed a highly crystalline structure, and the saturation magnetization of the as-prepared magnetite was strongly related to the particle size. Furthermore, the grafted PGMA content on the magnetic nanoparticles could be controlled by varying the ligand to transition metal ratio in a N,N,N‧,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr2 catalyst system. The maximum grafted content was 23.1% at a ratio of [PMDETA]0/[CuBr2]0 = 2:1.

  3. The association between content of the elements S, Cl, K, Fe, Cu, Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis

    DEFF Research Database (Denmark)

    Laursen, Jens; Milman, Nils; Pind, Niels;

    2014-01-01

    PROJECT: Meta-analysis of previous studies evaluating associations between content of elements sulphur (S), chlorine (Cl), potassium (K), iron (Fe), copper (Cu), zinc (Zn) and bromine (Br) in normal and cirrhotic autopsy liver tissue samples. PROCEDURE: Normal liver samples from 45 Greenlandic...... Inuit, median age 60 years and from 71 Danes, median age 61 years. Cirrhotic liver samples from 27 Danes, median age 71 years. Element content was measured using X-ray fluorescence spectrometry. STATISTICS: Dual hierarchical clustering analysis, creating a dual dendrogram, one clustering element....... The analysis discriminated between elements in normal and cirrhotic livers. The other dendrogram clustered elements in four clusters: sulphur and chlorine; copper and bromine; potassium and zinc; iron. There were significant correlations between the elements in normal liver samples: S was associated with Cl, K...

  4. Electrical conductivity studies on CuBr containing Al2O3 particles

    Science.gov (United States)

    Dubec, P. M.; Wagner, J. B., Jr.

    1984-01-01

    The conductivity of CuBr was studied and the role of a second phase, Al2O3, dispersed in CuBr was tested. CuBr melts at 493 C and exhibits three phases in the solid state. CuBr is a good ionic conductor with a transport number for copper ions of virtually unity with weighed proportions of the appropriate chemicals used. The CuBr materials were heated above melting point of CuBr, and the samples were sandwiched between copper electrodes. The ac conductivity, was determined at 1 kHz between 25 and 440 C depending on the sample. It was shown that at low temperatures, the conductivity for CuBr (Al2O3) increased by as much as 100, whereas in the beta phase the conductivity of CuBr containing Al2O3 decreased. The electrical conductivity studies are in agreement with earlier data.

  5. A mechanism of Cu work function reduction in CsBr/Cu photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Matthew T.; Hess, Wayne P.; Shluger, AL

    2016-03-14

    Thin films of CsBr deposited on Cu(100) have been proposed as next-generation photocathode materials for applications in particle accelerators and free-electron lasers. However, the mechanisms underlying an improved photocathode performance remain poorly understood. We present density Functional Theory (DFT) calculations of the work function reduction following the application of CsBr thin film coatings to Cu photocathodes. The effects of structure and van der Waals forces are examined. Calculations suggest that CsBr films can reduce the work function by around 1.5 eV, which would explain the exponential increase in quantum efficiency (QE) of coated vs. uncoated photocathodes. A model explaining experimentally observed laser activation of photocathode is provided whereby the photo-induced creation of di-vacancies at the surface, and their subsequent diffusion throughout the lattice and segregation at the interface leads to a further increase in QE after a period of laser irradiation.

  6. GMI in FeCuNbSiB/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Correa, M.A. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil)]. E-mail: mmacorrea@gmail.com; Viegas, A.D.C. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Silva, R.B. da [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Andrade, A.M.H. de [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Sommer, R.L. [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro, RJ (Brazil)

    2006-10-01

    Very high magnetoimpedance (MI) measured at frequencies up to 1.8 GHz in single and multilayered thin films with composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} and (Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9}+Cu) are reported. The magnetic properties of both systems are also compared. MI ratio as high as 300% for the multilayered samples were obtained.

  7. {[Cu2Br3]n[Cu(H-Leof)2]·2H2O} where Leof is Levofloxacin%{[Cu2Br3]n[Cu(H-Leof)2]·2H2O}(Leof是左氟沙星)

    Institute of Scientific and Technical Information of China (English)

    王锡森; 唐云志; 熊仁根

    2005-01-01

    The crystal structure of {[Cu2Br3]n[Cu(H-Leof)2]· 2H2O} (1) comprises of [Cu(H-Leof)2] + cations, [Cu2Br3]nanions and lattice water molecules. And anion is a 1-D chain formed through alternative Cu-Br dimer and triangular geometry. CCDC: 274841.

  8. RbCuFe(PO42

    Directory of Open Access Journals (Sweden)

    Mongi Ben Amara

    2013-08-01

    Full Text Available A new iron phosphate, rubidium copper(II iron(III bis(phosphate, RbCuFe(PO42, has been synthesized as single crystals by the flux method. This compound is isostructural with KCuFe(PO42 [Badri et al. (2011, J. Solid State Chem. 184, 937–944]. Its structure is built up from Cu2O8 units of edge-sharing CuO5 polyhedra, interconnected by FeO6 octahedra through common corners to form undulating chains that extend infinitely along the [011] and [01-1] directions. The linkage of such chains is ensured by the PO4 tetraedra and the resulting three-dimensional framework forms quasi-elliptic tunnels parallel to the [101] direction in which the Rb+ cations are located.

  9. [Oxidation of mercury by CuBr2 decomposition under controlled-release membrane catalysis condition].

    Science.gov (United States)

    Hu, Lin-Gang; Qu, Zan; Yan, Nai-Qiang; Guo, Yong-Fu; Xie, Jiang-Kun; Jia, Jin-Ping

    2014-02-01

    CuBr2 in the multi-porous ceramic membrane can release Br2 at high temperature, which was employed as the oxidant for Hg0 oxidation. Hg0 oxidation efficiency was studied by a membrane catalysis device. Meanwhile, a reaction and in situ monitoring device was designed to avoid the impact of Br2 on the downstream pipe. The result showed that the MnO(x)/alpha-Al2O3 catalysis membrane had a considerable "controlled-release" effect on Br2 produced by CuBr2 decomposition. The adsorption and reaction of Hg0 and Br2 on the surface of catalysis membrane obeyed the Langmuir-Hinshelwood mechanism. The removal efficiency of Hg0 increased with the rising of Br2 concentration. However, when Br2 reached a certain concentration, the removal efficiency was limited by adsorption rate and reaction rate of Hg0 and Br2 on the catalysis membrane. From 473 K to 573 K, the variation of Hg0 oxidation efficiency was relatively stable. SO2 in flue gas inhibited the oxidation of Hg0 while NO displayed no obvious effect.

  10. Modeling of Output Characteristics of a UV Cu+ Ne-CuBr Laser

    Directory of Open Access Journals (Sweden)

    Snezhana Georgieva Gocheva-Ilieva

    2012-01-01

    Full Text Available This paper examines experiment data for a Ne-CuBr UV copper ion laser excited by longitudinal pulsed discharge emitting in multiline regime. The flexible multivariate adaptive regression splines (MARSs method has been used to develop nonparametric regression models describing the laser output power and service life of the devices. The models have been constructed as explicit functions of 9 basic input laser characteristics. The obtained models account for local nonlinearities of the relationships within the various multivariate subregions. The built best MARS models account for over 98% of data. The models are used to estimate the investigated output laser characteristics of existing UV lasers. The capabilities for using the models in predicting existing and future experiments have been demonstrated. Specific analyses have been presented comparing the models with actual experiments. The obtained results are applicable for guiding and planning the engineering experiment. The modeling methodology can be applied for a wide range of similar lasers and laser devices.

  11. Hyperfine and magnetic properties of Fe-Cu clusters and Fe precipitates embedded in a Cu matrix

    Energy Technology Data Exchange (ETDEWEB)

    Klautau, A B [Faculdade de Fisica, Universidade Federal do Para, 66075-110, Belem, PA (Brazil); Socolovsky, L M [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires, C1063ACV, Buenos Aires (Argentina); Nogueira, R N [Faculdade Taboao da Serra, 06768-000, Taboao da Serra, SP (Brazil); Petrilli, H M, E-mail: aklautau@ufpa.b [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

    2009-12-16

    Using the first-principles real-space linear muffin-tin orbital method within the atomic sphere approximation (RS-LMTO-ASA) we study hyperfine and local magnetic properties of substituted pure Fe and Fe-Cu clusters in an fcc Cu matrix. Spin and orbital contributions to magnetic moments, hyperfine fields and the Moessbauer isomer shifts at the Fe sites in Fe precipitates and Fe-Cu alloy clusters of sizes up to 60 Fe atoms embedded in the Cu matrix are calculated and the influence of the local environment on these properties is discussed.

  12. A Comparative Kinetics Study between Cu/SSZ-13 and Fe/SSZ-13 SCR Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Wang, Yilin; Kollar, Marton; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2015-11-09

    Cu- and Fe/SSZ-13 catalysts with the same Cu(Fe)/Al ratios are synthesized using the same parent SSZ-13 starting material. The catalytic performance for both fresh and hydrothermally aged catalysts is tested with NO and NH3 oxidation, and standard SCR reactions under steady-state conditions, and standard and fast SCR under temperature-programmed conditions. For standard SCR, Cu/SSZ-13 shows much better low-temperature performance which can be explained by NH3-inhibition of Fe/SSZ-13. During hydrothermal aging, both catalysts undergo dealumination but Fe/SSZ-13 dealuminates more severely. For aged catalysts, Cu/SSZ-13 gains oxidation activities due to formation of CuOx. However, Fe/SSZ-13 loses oxidation activities although formation of FeOx clusters and FeAlOx species also occur. Because of such physical properties differences, aged Cu/SSZ-13 loses while Fe/SSZ-13 maintains high-temperature SCR selectivities. A physical mixture of aged catalysts provides stable SCR performance in a wide temperature range and is able to decrease N2O formation at high reaction temperatures. This suggests that Fe/SSZ-13 can be used as a cocatalyst for Cu/SSZ-13 for transportation applications. During temperature-programmed SCR reactions, weak hysteresis is found during standard SCR due to NH3 inhibition. For fast SCR, hysteresis caused by NH4NO3 inhibition is much more significant. NH4NO3 deposition is greatly enhanced by Brønsted and Lewis acidity of the catalysts.

  13. Antiperovskite Chalco-Halides Ba3(FeS4)Cl, Ba3(FeS4)Br, and Ba3(FeSe4)Br with Spin Super-Super Exchange

    OpenAIRE

    Xian Zhang; Kai Liu; Jian-Qiao He; Hui Wu; Qing-Zhen Huang; Jian-Hua Lin; Zhong-Yi Lu; Fu-Qiang Huang

    2015-01-01

    Perovskite-related materials have received increasing attention for their broad applications in photovoltaic solar cells and information technology due to their unique electrical and magnetic properties. Here we report three new antiperovskite chalco-halides: Ba3(FeS4)Cl, Ba3(FeS4)Br, and Ba3(FeSe4)Br. All of them were found to be good solar light absorbers. Remarkably, although the shortest Fe-Fe distance exceeds 6 Å, an unexpected anti-ferromagnetic phase transition near 100 K was observed ...

  14. Fe and Cu isotope mass balances in the human body

    Science.gov (United States)

    Balter, V.; Albarede, F.; Jaouen, K.

    2011-12-01

    The ranges of the Fe and Cu isotope compositions in the human body are large, i.e. ~3% and ~2%, respectively. Both isotopic fractionations appear to be mainly controlled by redox conditions. The Fe and Cu isotope compositions of the tissues analyzed so far plot on a mixing hyperbolae between a reduced and an oxidized metals pools. The reduced metals pool is composed by erythrocytes, where Fe is bounded to hemoglobin as Fe(II) and Cu to superoxide-dismutase as Cu(I). The oxidized metals pool is composed by hepatocytes, where Fe and Cu are stored as Fe(III) ferritin and as Cu(II) ceruloplasmine, respectively. The position of each biological component in the δ56Fe-δ65Cu diagram therefore reflects the oxidation state of Fe and Cu of the predominant metal carrier protein and allows to quantify Fe and Cu fluxes between organs using mass balance calculations. For instance, serum and clot Fe and Cu isotope compositions show that current biological models of erythropoiesis violates mass conservation requirements, and suggest hidden Fe and Cu pathways during red blood cells synthesis. The results also show that a coupled Fe-Cu strong gender isotopic effect is observed in various organs. The isotopic difference between men and women is unlikely to be due to differential dietary uptake or endometrium loss, but rather reflects the effect of menstrual losses and a correlative solicitation of hepatic stores. We speculate that thorough studies of the metabolism of stable isotopes in normal conditions is a prerequisite for the understanding of the pathological dysregulations.

  15. Electrodeposited Ni,Fe,Co and Cu single and multilayer nanowire arrays on anodic aluminum oxide template

    Institute of Scientific and Technical Information of China (English)

    Bobomurod HAMRAKULOV; In-Soo KIM; M.G.LEE; B.H.PARK

    2009-01-01

    The Ni, Fe, Co and Cu single and multilayer nanowire arrays to make perpendicular magnetic recording media were fabricated with nanoporous anodic aluminum oxide (AAO) templates from Watt solution and additives by the DC electrodeposition. The results show that the diameters of Ni, Fe, Co and Cu single and multilayer nanowires in AAO templates are 40-80 nm and the lengths are about 30 μm with the aspect ratio of 350-750. The magnetic properties of the prepared nanowires are different under different electrodepositing conditions. The remanences (Br) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires, and coercivity (Hc) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires. These are compatible with the required conditions of high density magnetic media devices that should have the low coercivity to easily success magnetization and high remanence to keep magnetization after removal of magnetic field.

  16. Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

    Science.gov (United States)

    Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

    2011-12-01

    Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

  17. Magnetic dilution in the cadmium-doped spin ladder compound Cdx Cu1 - x (quinoxaline) Br2

    Science.gov (United States)

    Keith, Brian; Landee, Chris; Turnbull, Mark

    2011-03-01

    Both Cu (quinoxaline) (Br2) and Cu (quinoxaline) (Cl2) are examples of molecule-based magnets where the CuX4 dimers are linked into ladders by quinoxaline molecules, where X is either Cl or Br. The rung exchange occurs through the bridging halides while the rail exchange occurs through the quinoxaline rings. Introducing random rung interactions into the system [ Cu (quinoxaline) (Br2)1-x (Cl2)x ] has caused the spin gap to close, in contrast with the gapped pure spin ladder parents. Crystal growth of non-magnetic-doped molecular magnets, CdxCu1 - x (2 , 3 - dimethylpyrazine)Br2 , have been performed for several values of the nominal conentration, x, and have been confirmed. The magnetizations and susceptibilities of the magnetically diluted ladder assemblage are presented along with a comparison of the effects of dilution from the pure case (x=0).

  18. Charge transfer and relativistic effects in the low-lying electronic states of CuCl, CuBr and CuI

    NARCIS (Netherlands)

    Sousa, C; DeJong, WA; Broer, R; Nieuwpoort, WC; Jong, W.A. de

    1997-01-01

    The spectral transitions and the character of the low-lying excited states of the copper halides, CuX (X = Cl, Br, I) are studied by means of two different relativistic computational approaches. One is based on the CASSCF/CASPT2 approach with operators accounting for scalar relativistic effects eval

  19. Coordination variation of hydrated Cu2+/Br1- ions traversing the interfacial water in mesopores

    Science.gov (United States)

    Wang, Q.; Huang, X. F.; Li, C. X.; Pan, L. Q.; Wu, Z. H.; Hu, T. D.; Jiang, Z.; Huang, Y. Y.; Cao, Z. X.; Sun, G.; Lu, K. Q.

    2012-06-01

    Resolution of the atomistic and electronic details about the coordination structure variation of hydrated ions in the interfacial water is still a tough challenge, which is, however, essentially important for the understanding of ion adsorption, permeation and other similar processes in aqueous solutions. Here we report the tracing of coordination structure variation for hydrated Cu2+/Br1- ions traversing the interfacial water in Vycor mesopores (ϕ = 7.6 nm) by employing both X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopies. By controlled desorption/adsorption of water, the filling fraction of the mesopores, thus the water layer thickness, can be adjusted, which in turn effects the variation of coordination structure of the ions therein. It is found that both Cu2+ and Br1- ions prefer staying exclusively in the core water, and in this circumstance no ion pairs have been detected in the solution of concentrations up to 1.0 M. Following capillary decondensation occurring at a filling fraction of ˜35% which corresponds to a water layer of about three monolayers, Br1- ions begin immediately to reconstruct their first coordination shell, characterized by ionic dehydration, shrinkage of ion-water bond length, and formation of ion pairs. In contrast, Cu2+ ions can retain a bulk-like coordination structure till being driven to bond directly to the pore surface when the filling fraction is below 20%. At the final stage of dehydration via thermal vacuum treatment at 110°C, Cu2+ ions can be completely reduced to the Cu1+ state, and recover at room temperature only when the filling fraction is above 14%. These results may be inspirable for the investigation of similar problems concerning hydrated ions in water solution under different confining conditions.

  20. Coordination variation of hydrated Cu2+/Br1− ions traversing the interfacial water in mesopores

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2012-06-01

    Full Text Available Resolution of the atomistic and electronic details about the coordination structure variation of hydrated ions in the interfacial water is still a tough challenge, which is, however, essentially important for the understanding of ion adsorption, permeation and other similar processes in aqueous solutions. Here we report the tracing of coordination structure variation for hydrated Cu2+/Br1- ions traversing the interfacial water in Vycor mesopores (ϕ = 7.6 nm by employing both X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopies. By controlled desorption/adsorption of water, the filling fraction of the mesopores, thus the water layer thickness, can be adjusted, which in turn effects the variation of coordination structure of the ions therein. It is found that both Cu2+ and Br1- ions prefer staying exclusively in the core water, and in this circumstance no ion pairs have been detected in the solution of concentrations up to 1.0 M. Following capillary decondensation occurring at a filling fraction of ∼35% which corresponds to a water layer of about three monolayers, Br1- ions begin immediately to reconstruct their first coordination shell, characterized by ionic dehydration, shrinkage of ion-water bond length, and formation of ion pairs. In contrast, Cu2+ ions can retain a bulk-like coordination structure till being driven to bond directly to the pore surface when the filling fraction is below 20%. At the final stage of dehydration via thermal vacuum treatment at 110°C, Cu2+ ions can be completely reduced to the Cu1+ state, and recover at room temperature only when the filling fraction is above 14%. These results may be inspirable for the investigation of similar problems concerning hydrated ions in water solution under different confining conditions.

  1. Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Canellas, C.G.L. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Carvalho, S.M.F. [State Institute of Hematology Arthur de Siqueira Cavalcanti, 20.211-030 Rio de Janeiro (Brazil); Anjos, M.J. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro, 20.559-900 Rio de Janeiro (Brazil); Lopes, R.T., E-mail: ricardo@lin.ufrj.br [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil)

    2012-07-15

    In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18-50 suffering from SCA and sixty healthy volunteers aged 18-60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: Black-Right-Pointing-Pointer Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. Black-Right-Pointing-Pointer It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Black-Right-Pointing-Pointer There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. Black-Right-Pointing-Pointer The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

  2. Thermal stability of Al-Cu-Fe icosahedral alloys

    Science.gov (United States)

    Bessière, M.; Quivy, A.; Lefebvre, S.; Devaud-Rzepski, J.; Calvayrac, Y.

    1991-12-01

    A stable ideally quasiperiodic phase exists in a small range of concentration, close to the composition Al{62}Cu{25.5}Fe{12.5}. Reducing the iron content, or replacing small amounts of copper by aluminium, lead to icosahedral alloys which exhibit around 650 ^{circ}C structural transformations of unclear nature: in the X-ray powder diffraction pattern, the peak profiles become purely Lorentzian (Al{62.3}Cu{25.3}Fe{12.4}) or diffuse “side-bands” appear in the tails of the Bragg peaks (Al{63}Cu{24.5}Fe{12.5}). In the last case long annealing treatments eventually transform the Bragg peaks into diffuse peaks located at positions clearly off the ideal icosahedral symmetry. Small deviations from this composition range lead to Bragg peaks with shoulders whatever the heat-treatment may be; perfect icosahedral order is never obtained for these compositions (Al{63,25}Cu{24,5}Fe{12,25}, Al{64}Cu{24}Fe{12}, Al{63}Cu{25}Fe{12}). Une phase stable idéalement quasipériodique existe dans un petit domaine de concentration, au voisinage de la composition Al{62}Cu{25,5}Fe{12,5}. La diminution de la teneur en fer, ou le remplacement de faibles quantités de cuivre par de l'aluminium, conduisent à des alliages icosaédriques qui subissent vers 650 ^{circ}C des transformations structurales dont la nature n'est pas clairement identifiée: dans le diagramme de diffraction des rayons X sur poudre, les profils de raies deviennent purement Lorentziens (Al{62,3}Cu{25,3}Fe{12,4}) ou bien des raies diffuses apparaissent dans le pied des pics de Bragg (Al{63}Cu{24,5}Fe{12,5}). Dans ce dernier cas un long traitement de recuit transforme finalement les pics de Bragg en des pics diffus localisés à des positions clairement en dehors de celles correspondant à la symétrie icosaédrique idéale. De faibles écarts à ce domaine de compositions conduisent à des diagrammes de rayons X où les pics de Bragg sont épaulés quel que soit le traitement thermique ; l'ordre icosaédrique parfait n

  3. Spin-current injection and detection in κ-(BEDT-TTF2Cu[N(CN2]Br

    Directory of Open Access Journals (Sweden)

    Z. Qiu

    2015-05-01

    Full Text Available Spin-current injection into an organic semiconductor κ-(BEDT-TTF2Cu[N(CN2]Br film induced by the spin pumping from an yttrium iron garnet (YIG film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF2Cu[N(CN2]Br film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF2Cu[N(CN2]Br. We found that the voltage signal in the κ-(BEDT-TTF2Cu[N(CN2]Br/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions.

  4. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    International Nuclear Information System (INIS)

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe86B7C7 alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe3C and α-Fe phase impedes the devitrification. • Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity

  5. Preparation of 24Mg-Fe-Cu Target

    Institute of Scientific and Technical Information of China (English)

    FAN; Qi-wen; DU; Ying-hui; ZHANG; Rong

    2012-01-01

    <正>The three-layer-sandwich targets of 24Mg-Fe-Cu needed to be prepared in the physics experiment. The middle layers are thin ferromagnetic Fe layers of about 3.2 mg/cm2. The recoil stopper layers are thick crystallized and defect-free Cu layers of about 15 mg/cm2. The thickness of the 24Mg target layers is about 300 μg/cm2, and the uniformity should be better than 90%.

  6. Superparamagnetism in CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grima-Gallardo, P.; Alvarado, F.; Munoz, M.; Duran, S.; Quintero, M.; Nieves, L.; Quintero, E.; Tovar, R.; Morocoima, M. [Centro de Estudios en Semiconductores (CES), Fac. Ciencias, Dpto. Fisica, Universidad de Los Andes, Merida (Venezuela); Ramos, M.A. [Laboratorio de Difraccion y Fluorescencia de Rayos-X, Instituto Zuliano de Investigaciones Tecnologicas (INZIT), La Canada de Urdaneta, Estado Zulia (Venezuela)

    2012-06-15

    The temperature dependencies of DC magnetic susceptibilities, {chi}(T), of CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys were measured in a SQUID apparatus using the protocol of field cooling (FC) and zero FC (ZFC). The FC curves of both samples reflect a weak ferromagnetic (or ferrimagnetic) behavior with a nearly constant value of {chi}(T) in the measured temperature range (2-300 K) indicating that the critical temperatures (T{sub c}) are >300 K. The ZFC curves diverges from FC, showing irreversibility temperatures (T{sub irr}) of {proportional_to}250 K for CuFeInTe{sub 3} and >300 K for CuFeGaTe{sub 3}, suggesting that we are dealing with cluster-glass systems in a superparamagnetic state. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Cu clustering stage before the crystallization in Fe-Si-B-Nb-Cu amorphous alloys

    DEFF Research Database (Denmark)

    Ohnuma, M.; Hono, K.; Onodera, H.;

    1999-01-01

    -enriched clusters. The average diameter and interparticle distance of the Cu-enriched clusters have also been estimated by SANS. An exothermic reaction is observed above the Curie Temperature in the DSC curves of the Fe-Si-B-Nb-Cu alloys. The onset temperature of the exothermic reaction is shifted to lower...... crystallization reaction. The number of the clusters estimated by 3DAP is large enough to provide heterogeneous nucleation sites to all bcc/D0(3) Fe-Si crystals which appear at higher temperatures. This fact indicates that the distribution of nanocrystalline Fe-Si is strongly affected by that of the Cu...

  8. Itinerant magnetism in metallic CuFe2Ge2.

    Science.gov (United States)

    Shanavas, K V; Singh, David J

    2015-01-01

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  9. Magnetic behaviour investigation on symmetric spin valves of Co/Cu/NiFe and NiFe/Cu/Co

    Institute of Scientific and Technical Information of China (English)

    李铁; 沈鸿烈

    2002-01-01

    In this paper, we have obtained and investigated the magnetic behaviours of the ferromagnetic layer in thesymmetric spin valves of Co/Cu/NiFe and NiFe/Cu/Co by measuring with a vibrating sample magnetometer andanalysing in terms of the multi-domain Ising models. It has been found that some magnetic layer can have quitedifferent magnetic behaviours in different structures of spin valves, depending on the properties of the under-layer. Inour investigation, we have found that the magnetic behaviour of a Co layer depends mainly on the magnetization of theunder-layer, whereas this is not the case for the NiFe layer.

  10. Effect of Cu surface segregation on the exchange coupling field of NiFe/FeMn bilayers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The NiFe/FeMn bilayers with different buffer layers (Ta or Ta/Cu) were prepared by magnetron sputtering.Results show that the exchange coupling field of NiFe/FeMn films with Ta buffer is higher than that of the films with Ta/ Cu buffer. We analysed the reasons by investigating the crystallographic texture, surface roughness and surface segregation of both films, respectively. We found that the decrease of the exchange coupling fields of NiFe/FeMn films with Ta/Cu buffer layers was mainly caused by the Cu surface segregation on NiFe surface.

  11. Magnetic properties of nanostructured CuFe2O4

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

    1999-01-01

    The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...... size while the coercive force, shift of the hysteresis loop, magnetic hardness, and saturation magnetization at 4.2 K increase with decreasing average grain size. At 295 K the coercive-field dependence on the average grain size is described, with particles showing superparamagnetic relaxation effects......-energy ball milling in an open container with grain sizes ranging from 9 to 61 nm. Superparamagnetic relaxation effects have been observed in milled samples at room temperature by Mossbauer and magnetization measurements. At 15 K, the average hyperfine field of CuFe2O4 decreases with decreasing average grain...

  12. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.D., E-mail: fanxd@seu.edu.cn; Shen, B.L., E-mail: blshen@seu.edu.cn

    2015-07-01

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe{sub 86}B{sub 7}C{sub 7} alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe{sub 3}C and α-Fe phase impedes the devitrification. • Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity.

  13. Stress-impedance effects in layered FeSiB/Cu/FeSiB films with a meander line structure

    International Nuclear Information System (INIS)

    Stress-impedance (SI) effects were realized in layered FeSiB/Cu/FeSiB films with a meander line structure by magnetron sputtering on thin glass substrate. The SI effects were studied in the frequency range of 1-40MHz for the layered FeSiB/Cu/FeSiB films with different film thickness of FeSiB film and Cu layer. Experimental results show that the values of SI ratio increase nearly linear with the deflection of the layered FeSiB/Cu/FeSiB films at high frequencies, and a large negative SI ratio of -18.3% at a frequency of 25MHz with the deflection of 1000μm is obtained in the layered FeSiB/Cu/FeSiB films with a thicker FeSiB film, which is very attractive for the applications of stress sensors

  14. Magnetic properties of nanostructured CuFe2O4

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

    1999-01-01

    The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...... size while the coercive force, shift of the hysteresis loop, magnetic hardness, and saturation magnetization at 4.2 K increase with decreasing average grain size. At 295 K the coercive-field dependence on the average grain size is described, with particles showing superparamagnetic relaxation effects...

  15. Characterization of Microstructure and Magnetic Properties of NdFeB Magnet with Dy, Al and Cu Additions

    Institute of Scientific and Technical Information of China (English)

    Lü Yousheng; Chen Yiqing; Su Yong; Cheng Wenhao; Xiong Yongfei; Yi Xiaofei; Zhou Qingtao

    2007-01-01

    A new alloy of Nd33.5Dy0.99Febal.Al0.52Cu0.1B1.15 (%, mass fraction) was fabricated by powder metallurgy. The effects of Dy, Al and Cu additions on the microstructure and magnetic properties of sintered NdFeB magnet were investigated. The additions of Dy, Al and Cu are effective to refine grains and improve coercivity. Moreover, suitable amounts of Dy, Al and Cu lead to a demagnetization curve with good rectangularity. It is found that the sintered NdFeB magnet has relatively high magnetic performance of Br=12.17kGs, jHc=13.52kOe and (BH)max=34.71MGOe. The sintered NdFeB sample was examined by magnetic force microscope which revealed the domain structures at the surface. It is revealed that the mean Nd2Fe14B grain size is significantly larger than the average scale of the magnetic contrast. An explanation about this is that most Nd2Fe14B grains in sintered NdFeB alloy are dominated with the muhidomain structures when the magnet is in thermally demagnetization state.

  16. Quantum-well states and induced magnetism in Fe/CuN/Fe bcc (001) trilayers

    DEFF Research Database (Denmark)

    Niklasson, A.M.N.; Mirbt, S.; Skriver, Hans Lomholt;

    1996-01-01

    We have used a first-principles Green's function technique to investigate the formation of magnetic moments in Fe/Cu-N/Fe bcc (001) trilayers. We show that the magnetic moment in the paramagnetic spacer material to a first approximation may be described as a linear superposition of the magnetic...

  17. Reactions of Cu(I)Br with aziridine derivatives. Synthesis, characterization and crystal structures of monomeric, dimeric and hexameric aziridine (= az) complexes of the formal type [CuBr(az)2]n (n = 1, 2) and [CuBr(az)]6.

    Science.gov (United States)

    Bobka, Roman; Roedel, J Nicolas; Wirth, Stefan; Lorenz, Ingo-Peter

    2010-11-14

    The first syntheses of monomeric and oligomeric aziridine complexes of copper(I) are described. Cu(I)Br (1) reacts with a series of different aziridine derivatives (C(2)H(3)PhNH (2), C(2)H(2)Me(2)NH (3), C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2) (4)) to give the neutral dimeric complex [CuBr(C(2)H(3)PhNH)(2)](2) (5) and the ionic hexameric complex [Cu(6)Br(5)(C(2)H(2)Me(2)NH)(6)]Br (6) with terminal bound aziridine ligands as well as the neutral monomeric complex [CuBr(C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2))] (7) where the dimerized aziridine acts as a N,N'-chelating ligand. After purification, all of the complexes were fully characterized and their IR, (1)H and (13)C NMR spectra are reported and discussed. The single crystal structure analysis revealed distorted tetrahedral geometry for the copper(I) centres in the complexes 5 and 6 and a trigonal planar structure for complex 7. In the oligomers the copper centres are bridged by two μ(2)- (5) or two μ(3)- and three μ(4)-bromido ligands (6), respectively.

  18. Magnetic transitions in botallackite-structure Cu{sub 2}(OH){sub 3}Br and Cu{sub 2}(OH){sub 3}I

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, X.G., E-mail: zheng@cc.saga-u.ac.j [Department of Physics, Faculty of Science and Engineering, Saga University, Saga 840-8502 (Japan); Department of Physics, School of Engineering, Saga University, Saga 840-8502 (Japan); Yamashita, T.; Hagihala, M.; Fujihala, M. [Department of Physics, School of Engineering, Saga University, Saga 840-8502 (Japan); Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Fukuoka 812-8581 (Japan)

    2009-04-15

    The deformed pyrochlore lattice compound clinoatacamite, Cu{sub 2}(OH){sub 3}Cl, shows intriguing magnetism and 1/4 substitution of Cu with nonmagnetic Zn leads to the two-dimensional kagome lattice ZnCu{sub 3}Cl{sub 2}(OH){sub 6} that exhibits spin liquid behaviour. These findings renewed interest in botallackite Cu{sub 2}(OH){sub 3}Cl, which is a polymorphous structure of clinoatacamite Cu{sub 2}(OH){sub 3}Cl possessing a two-dimensional triangular lattice. The present work investigates the effect of halogen ions on the magnetic transitions in the botallackite structure. Similar to the antiferromagnetic Cu{sub 2}(OH){sub 3}Cl (T{sub N}=7.2 K), Cu{sub 2}(OH){sub 3}Br and Cu{sub 2}(OH){sub 3}I both showed antiferromagnetic transitions at T{sub N}=10 and 14 K, respectively. Long-range order also exists in Cu{sub 2}(OH){sub 3}Br as exemplified by the muSR study. The experimental results suggest that the magnetic coupling on the triangular lattice is dominated by the super-exchange interaction through the halogen ions. Further detailed comparison studies on these botallackite-structure compounds are expected to clarify the spin configuration on this triangular lattice.

  19. Reduction of nitrobenzene by the catalyzed Fe/Cu process

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; LI Ping; FAN Jinhong

    2008-01-01

    The polarization behavior of the couple Fe/Cu in 100 mg/L nitrobenzene aqueous solution was studied using Evans coupling diagrams. The results indicated that the iron corrosion was limited by both anodic and cathodic half-cell reactions under the neutral conditions and cathodically controlled under the alkaline conditions. Batch experiments were performed to study the effect of solution pH, reaction duration, concentration, type of electrolyte and dissolved oxygen (DO) on the reduction of nitrobenzene by the catalyzed Fe/Cu process. This process proved effective in the pH range of 3 to 11. The conversion efficiency of nitrobenzene at pH ≈ 10.1 was almost the same as that under highly acid conditions (pH ≈ 3). The degradation of nitrobenzene fell into two phases: adsorption and surface reduction, and the influence of adsorption and mass transfer became more extensive with solution concentration. The reduction rate decreased in the presence of DO in the solution, indicating that a need for aeration was eliminated in the catalyzed Fe/Cu process. Accordingly, spending on energy consumption would be reduced. Economic analysis indicated that merely 0.05 kg was required for the treatment of a ton of nitrobenzene-containing water with pH from 3 to 11. The catalyzed Fe/Cu process is cost-effective and of practical value.

  20. Kinetic process of mechanical alloying in Fe50Cu50

    DEFF Research Database (Denmark)

    Huang, J.Y.; Jiang, Jianzhong; Yasuda, H.;

    1998-01-01

    It is shown that mechanical alloying in the immiscible Fe-Cu system is governed by the atomic shear event and shear-induced diffusion process. We found that an alpha-to-gamma phase transformation, as evidenced by the Nishiyama-Wasserman orientation relationship, occurs by simultaneous shearing...

  1. Preparation and characterization of electrodeposited Fe and Fe/Cu nanowires

    Science.gov (United States)

    Dubois, S.; Chassaing, E.; Duvail, J. L.; Piraux, L.; Waals, M. G.

    1999-09-01

    Fe and Fe/Cu multilayered nanowires with layer thicknesses in the 10nm range were successfully synthesized within the voids of nanoporous polycarbonate membranes and characterized by transmission electron microscopy. Magnetization measurements show that the shape anisotropy of individual Fe wires dominates the magnetic properties. Fe(8 nm)/Cu(10 nm) multilayered nanowires show CPP-GMR ratios as large as 12% at low temperature. The variations of the CPP-GMR as a function of the Cu layer thickness are consistent with the Valet-Fert model. Our data yield a value of about 0.3 for the bulk spin asymmetry coefficient β. Des nanofilaments constitués de Fe ou de multicouches Fe/Cu sont élaborés par dépôt électrochimique à l'intérieur des pores de membranes polycarbonate et caractérisés en microscopie électronique à transmission. Les propriétés magnétiques des nanofils de Fe sont très largement dominées par l'anisotropie de forme des fils. La magnéto-résistance géante (MRG) de multicouches Fe(8 nm)/Cu(10 nm) atteint 12 % à basse température tandis que la variation de la MRG est en bon accord avec le modèle de Valet-Fert. La valeur du coefficient d'asymétrie de spin β associé aux collisions au sein des couches de Fe est de l'ordre de 0.3.

  2. Spin-current injection and detection in κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Z., E-mail: qiuzy@imr.tohoku.ac.jp; Hou, D. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Uruichi, M. [Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585 (Japan); Uchida, K. [Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Yamamoto, H. M. [Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585 (Japan); RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan); Saitoh, E. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan)

    2015-05-15

    Spin-current injection into an organic semiconductor κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br. We found that the voltage signal in the κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions.

  3. The wavelength dependence of the photodissociation cross-section of CH 3Br chemisorbed on Cu{111}

    Science.gov (United States)

    Lamont, C. L. A.; Conrad, H.; Bradshaw, A. M.

    1993-01-01

    The photodissociation of methylbromide adsorbed on Cu{111} has been investigated as a function of the photon energy between 2.6 and 6.0 eV using a Xe arc lamp. The photodissociation products remaining on the surface, identified using HREELS, are CH 3 (in a C 3v configuration) and Br. In subsequent thermal desorption CH 4, C 2H 4, H 2 and CuBr are detected. The cross-section curve as a function of the wavelength shows an onset at 2.6 eV and a maximum of 1.2 × 10 -20 cm 2 at 3.5 eV. The results are compared with those obtained on a Pt{111} surface and both sets of data are interpreted within the framework of a one-step charge transfer model involving electron excitation from the substrate d-band into the σ ∗ CBr antibonding orbital.

  4. Time evolution of morphology in mechanically alloyed Fe-Cu

    KAUST Repository

    Wille, Catharina Gabriele

    2011-05-01

    Being widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility and characterised by a large positive heat of mixing. In addition to the detailed analysis of ball milled Fe-Cu powders by means of Atom Probe Tomography (APT), site specific structural analysis has been performed in this study using Transmission Electron Microscopy (TEM).In this contribution results on powders with low Cu concentrations (2.5-10 at%) are presented. Combining a ductile element (Cu, fcc) and a brittle one (Fe, bcc), striking differences in morphology were expected and found on all length-scales, depending on the mixing ratio of the two elements. However, not only could the atomic mixing of Fe and Cu be evaluated, but also the distribution of impurities, mostly stemming from the fabrication procedure. The combination of APT and TEM enables a correlation between the structural evolution and the chemical mixing during the milling process. For the first time, a clear distinction can be drawn between the morphological evolution at the surface and in the interior of the powder particles. This became possible owing to the site specific sample preparation of TEM lamellae by Focussed Ion Beam (FIB). Surprisingly, the texture arising from the ball milling process can directly be related to the classical rolling texture of cold rolled Fe. In addition, full homogeneity can be achieved even on the nano-scale for this material as shown by APT, resulting in an extended miscibility region in comparison to the equilibrium phase diagram. Grain sizes were determined by means of XRD and TEM. The strain corrected XRD results are in very good agreement with the values derived by TEM, both confirming a truly nanocrystalline structure. © 2011 Elsevier B.V.

  5. Itinerant magnetism in metallic CuFe2Ge2.

    Directory of Open Access Journals (Sweden)

    K V Shanavas

    Full Text Available Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  6. Nanophase stability in a granular FeRh-Cu system

    Science.gov (United States)

    Barua, Radhika; Jimenez-Villacorta, Felix; Shield, J. E.; Heiman, D.; Lewis, L. H.

    2013-05-01

    A granular system of FeRh-based nanoprecipitates (˜10-15 nm diameter) embedded in a rapidly solidified copper ribbon matrix was found to transit from a metastable tetragonal L10 (AuCu-1-type) structure to a stable B2 (CsCl-type) structure upon annealing-induced coarsening to ˜94 nm. The hysteretic magnetic transition observed at ˜100 K develops a gradual broadening that accompanies the L10 → B2 crystal structure transition. It is proposed that the Cu matrix influences the structural and magnetic properties of the FeRh-based nanoparticles through interfacial strain and chemical effects. These results emphasize the sensitivity of the magnetostructural response of FeRh to changes in the nanostructural scale, and provide pathways for tailoring the transition.

  7. The energetic and structural properties of bcc NiCu, FeCu alloys: a first-principles study

    OpenAIRE

    Xie, Yao-Ping; Zhao, Shi-Jin

    2011-01-01

    Using special quasirandom structures (SQS's), we perform first-principles calculations studying the metastable bcc NiCu and FeCu alloys which occur in Fe-Cu-Ni alloy steels as precipitated second phase. The mixing enthalpies, density of state, and equilibrium lattice parameters of these alloys are reported. The results show that quasi-chemical approach and vegard rule can well predict the energetic and structural properties of FeCu alloys but fail to yield that of NiCu. The reason rests with ...

  8. 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

  9. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se; Akansel, Serkan; Thersleff, Thomas; Brucas, Rimantas; Lansaker, Pia; Leifer, Klaus; Svedlindh, Peter [Department of Engineering Sciences, Uppsala University, 75121 Uppsala (Sweden); Harward, Ian; Celinski, Zbigniew [Department of Physics, University of Colorado, Colorado Springs, Colorado 80918 (United States); Ranjbar, Mojtaba; Dumas, Randy K. [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Jana, Somnath; Pogoryelov, Yevgen; Karis, Olof [Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Åkerman, Johan [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista (Sweden)

    2015-01-26

    Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

  10. Phase Transformations in Low-Fe Alloys of the Al-Cu-Fe System

    Institute of Scientific and Technical Information of China (English)

    Liming Zhang

    2004-01-01

    Microstructure and phase transformation in the Al-Cu-Fe alloys of the approximate compositional range of 20 -50 at.% Cu and 2 - 10 Fe at.% have been investigated from samples quenched from their respective temperatures by means of different thermal analysis, magnetothermal analysis, scanning electron microscopy, electron probe analysis and powder X-ray diffraction. Representative phase transformations categorized as polymorphic, discontinuous precipitation,quasi-binary eutectoid, and ternary transitional U-type phase transformation are presented. These phase transformations were found to have a common feature which consumes the β phase and appears the φ phase. A schematic diagram was proposed to demonstrate the transition processes with decreasing temperature.

  11. Ionothermal synthesis and structural characterization of [Cu(C4H6N2)4]Br2 and [Ni(C4H6N2)4]Br2

    Indian Academy of Sciences (India)

    Hong Wang; Bin Lu; Jingxiang Zhao; Qinghai Cai

    2015-07-01

    The ionothermal synthesis and spectroscopic, thermal and structural characterization of two new compounds [Cu(C4H6N2)4]Br2 (1) and [Ni(C4H6N2)4]Br2 (2) [(C4H6N2) = N-methylimidazole] are reported. In both 1 and 2, the central metal Cu (or Ni) ion adopts a square planar geometry and is bonded to the N-atoms of four terminal N-methylimidazole ligands.

  12. Magnetoresistive properties of multilayer film systems based on Fe/Cu and Fe/Cr

    Directory of Open Access Journals (Sweden)

    O.V. Synashenko

    2009-01-01

    Full Text Available Magnetoresistive properties of multilayer film systems based on Fe and Cu or Cr were investigated at room temperature. Factors, which influence on the magnetoresistance (MR value change, were studied. In Fe/Cu film system, in which the individuality of separate layers holds, the substrate change from amorphous pyroceramic to monocrystalline Si(111 leads to the MR ratio increase by 35 %, that is connected with magnetic ordering in bottom epitaxial Fe layer. Thermal annealing of the samples to 700 K leads to vanishing of the odd effect in MR in perpendicular geometry and MR increase by two times in parallel geometries. Investigations of [Fe(dFe/Cr(1]10 system showed, that the Fe thickness changes from 0,31 to 1,5 nm, and this leads to the MR magnitude change from 0,03-0,05 % to 1-3 % subject to the different measurement geometries, which is interpreted by Fe granule formation in matrix of solid solution (Fe, Cr.

  13. Low temperature penetration depth of κ-(ET)2Cu[N(CN)2]Br

    Science.gov (United States)

    Fletcher, J. D.; Carrington, A.; Giannetta, R. W.; Schlueter, J.

    2007-03-01

    Several experimental results have suggested that the quasi-2D organic metal κ-(ET)2Cu[N(CN)2]Br is host to some form of unconventional superconductivity. The presence of gap nodes in the superconducting order parameter should be detectable through power law behavior in the penetration depth at low temperature. The most accurate measurements of the temperature dependent penetration depth to date show a fractional power law, λT^1.5. However, these measurements were not performed at sufficiently low temperatures to determine whether this was due to the combination of gap nodes and the effects of impurity scattering, or due to an intrinsic form of exotic pair excitation. Using a radio frequency (rf) tunnel diode technique in a dilution fridge we have extended these measurements to T ˜ 75 mK (˜0.006 Tc). Special care has been taken to eliminate heating effects at these temperatures due to the presence of the small applied rf field. Data at the lowest temperature are more consistent with a nodal state in the presence of impurities.

  14. Mechanical alloying in the Fe-Cu system

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gente, C.; Bormann, R.

    1998-01-01

    in the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms...... for the preparation of materials under highly non-equilibrium conditions in systems with positive heats of mixing by mechanical alloying....

  15. Structural properties of amorphous and nanocrystallized Fe-Cu-Nb-Si-B and Fe-Gd-Cu-Nb-Si-B ribbons

    International Nuclear Information System (INIS)

    The influence of Gd addition on the structural properties of Fe-Cu-Nb-Si-B nanocrystallized and amorphous alloys is studied. The crystallization temperature increases and the microstructure of the annealed samples changes. Gd addition induces the formation of Gd-Fe-B phases. In fully crystallized Fe-Gd-Cu-Nb-Si-B alloys the α-Fe(Si), Fe-Nb-B, Gd3Fe62B14 and Gd1.1Fe4B4 phases are observed. The evolution of the microstructure is followed as a function of the cumulative effects of annealing time and temperature. The results suggest the transformation of the metastable Gd3Fe62B14 phase into Gd1.1Fe4B4 and α-Fe. The hyperfine parameters of the Gd3Fe62B14 Moessbauer contribution are reported. (orig.)

  16. Thermal spikes in Ag/Fe and Cu/Fe ion beam mixing

    International Nuclear Information System (INIS)

    Ion beam mixing has been studied since 1980, and since then a lot of experimental and theoretical work has been done and knowledge has been gathered. Nevertheless, there are still many fundamental aspects that need to be clarified and with that aim many experiments need to be performed. Copper and iron are miscible in the liquid state, while silver and iron are not. However, both systems are thermally immiscible in the solid state. In order to have an insight into the importance of mixing within thermal spikes during ion beam irradiation, we deposited Cu/Fe and Ag/Fe bilayers onto Si substrates and irradiated them at room temperature with 2 MeV Cu and 2.5 MeV Au ions. A combination of Rutherford backscattering spectrometry (RBS) and atomic force microscopy (AFM) was used to analyze the atomic transport at the interface and the morphology changes of the samples. From the element profiles at the interface we conclude a mixing efficiency, which is indeed larger than the prediction of the ballistic model in the Cu/Fe system and smaller in the Ag/Fe system. Since ballistic mixing is expected in any case, we argue that demixing and phase separation in the Ag/Fe system occur in the thermal spike phase of the cascade as a consequence of the positive heat of mixing. Further mixing does occur in the thermal spike in the Cu/Fe system and they remain mixed even at the solid state because of the high cooling rate. In addition, ion irradiation induces a large surface roughening of the Ag and Cu top layers as proven by AFM. This effect is important for the correct interpretation of the results. Furthermore, this recrystallization affects also the interface, producing a rough interface, that appears in the RBS spectra as an atomic 'diffusion' at the interface

  17. Synchrotron X-Ray Study on Structures of Ni80Fe20/Cu Superlattices

    Institute of Scientific and Technical Information of China (English)

    XU Ming; LUO Guang-Ming; CHAI Chun-Lin; YANG Tao; MAI Zhen-Hong; LAI Wu-Yan; WU Zhong-Hua; WANG De-Wu

    2001-01-01

    We have shown that, in contrast to the results in the literature, the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element (Cu). The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak. Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices. Upon annealing, the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.

  18. Three novel Cu6S6 cluster-based coordination compounds: synthesis, framework modulation and the sensing of small molecules and Fe(3+) ions.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Si-Zhe; Zhou, Rui-Sha; Shao, Jia; Qiu, Xiao-Min; Jia, Ying-Ying; Wang, Jun; Zhang, Xiao

    2016-08-01

    Three novel Cu6S6 cluster-based coordination compounds formulated as [Cu(mpymt)3]2 (1), {(CuBr4)[Cu(mpymt)6]}n (2), and {(CuI6)[Cu(mpymt)6]}n (3) (Hmpymt = 4-methylpyrimidine-2-thione), have been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 shows a distorted octahedral core of six copper atoms (Cu6S6) constructed from four α and two β type N[double bond, length as m-dash]C-SH parts from six mpymt(-) anions. Compound 2 displays an interesting 3D framework constructed from Cu6S6 and Cu4Br4 Cu(i) clusters simultaneously, interestingly, six mpymt(-) with α type N[double bond, length as m-dash]C-SH parts are involved in the formation of Cu6S6. Compound 3 displays an infinite 1D framework constructed from Cu6S6 and Cu6I6 Cu(i) clusters, notably, four α and two β type N[double bond, length as m-dash]C-SH parts are involved in the formation of the Cu6S6 cluster, however, only mpymt(-) ligands containing α type N[double bond, length as m-dash]C-SH parts form the bridged Cu6I6 cluster. The experimental results reveal that halogen ions finely modulate the structural features of compounds 1-3. The fluorescent properties of compounds 1-3 in the solid state and in various solvent emulsions were investigated in detail, the results of which indicate that compounds 1-3 are all highly sensitive naked eye colorimetric sensors for NB, 2-NT and Fe(3+) (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

  19. Three novel Cu6S6 cluster-based coordination compounds: synthesis, framework modulation and the sensing of small molecules and Fe(3+) ions.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Si-Zhe; Zhou, Rui-Sha; Shao, Jia; Qiu, Xiao-Min; Jia, Ying-Ying; Wang, Jun; Zhang, Xiao

    2016-08-01

    Three novel Cu6S6 cluster-based coordination compounds formulated as [Cu(mpymt)3]2 (1), {(CuBr4)[Cu(mpymt)6]}n (2), and {(CuI6)[Cu(mpymt)6]}n (3) (Hmpymt = 4-methylpyrimidine-2-thione), have been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 shows a distorted octahedral core of six copper atoms (Cu6S6) constructed from four α and two β type N[double bond, length as m-dash]C-SH parts from six mpymt(-) anions. Compound 2 displays an interesting 3D framework constructed from Cu6S6 and Cu4Br4 Cu(i) clusters simultaneously, interestingly, six mpymt(-) with α type N[double bond, length as m-dash]C-SH parts are involved in the formation of Cu6S6. Compound 3 displays an infinite 1D framework constructed from Cu6S6 and Cu6I6 Cu(i) clusters, notably, four α and two β type N[double bond, length as m-dash]C-SH parts are involved in the formation of the Cu6S6 cluster, however, only mpymt(-) ligands containing α type N[double bond, length as m-dash]C-SH parts form the bridged Cu6I6 cluster. The experimental results reveal that halogen ions finely modulate the structural features of compounds 1-3. The fluorescent properties of compounds 1-3 in the solid state and in various solvent emulsions were investigated in detail, the results of which indicate that compounds 1-3 are all highly sensitive naked eye colorimetric sensors for NB, 2-NT and Fe(3+) (NB = nitrobenzene and 2-NT = 2-nitrotoluene). PMID:27377475

  20. Superconducting spin valve effect and triplet superconductivity in CoO$_x$/Fe1/Cu/Fe2/Cu/Pb multilayer

    OpenAIRE

    Leksin, P. V.; Garifyanov, N. N.; Kamashev, A. A.; Fominov, Ya. V.; Schumann, J.; Hess, C.; KATAEV V.; Buechner, B.; Garifullin, I. A.

    2015-01-01

    We report magnetic and superconducting properties of the modified spin valve system CoOx/Fe1/Cu/Fe2/Cu/Pb. Introduction of a Cu interlayer between Fe2 and Pb layers prevents material interdiffusion process, increases the Fe2/Pb interface transparency, stabilizes and enhances properties of the system. This allowed us to perform a comprehensive study of such heterostructures and to present theoretical description of the superconducting spin valve effect and of the manifestation of the long-rang...

  1. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    Science.gov (United States)

    Sirohi, Anshu; Singh, Chandan K.; Thakur, Gohil S.; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Haque, Zeba; Gupta, L. C.; Kabir, Mukul; Ganguli, Ashok K.; Sheet, Goutam

    2016-06-01

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (˜47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  2. Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

    International Nuclear Information System (INIS)

    Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly (α = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

  3. Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T., E-mail: catarine@lin.ufrj.b, E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear. Lab. de Instrumentaco Nuclear; Carvalho, Silvia M.F., E-mail: silvia@hemorio.rj.gov.b [State Institute of Hematology Arthur de Siqueira Cavalcanti (HEMORIO), Rio de Janeiro, RJ (Brazil); Bellido, Alfredo Victor B., E-mail: alfredo@ien.gov.b [Federal Fluminense University (UFF), Niteroi, RJ (Brazil). Chemistry Inst.; Anjos, Marcelino J., E-mail: marcelin@lin.ufrj.b [State University of Rio de Janeiro (UERJ), RJ (Brazil). Physics Inst.

    2011-07-01

    Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly ({alpha} = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

  4. CuFe2 O4 -CuO Nanocomposites as Promising Materials for Solar Hydrogen Generation

    Science.gov (United States)

    Razavi, Mehdi; Amrollahi, Pouya; Yazdimamaghani, Mostafa; Tayebi, Lobat; Vashaee, Daryoosh

    2014-03-01

    Currently, hydrogen is produced, almost exclusively, by waterelectrolysis. This method can take advantage of economies of scale and most established techniques of producing hydrogen. We developed a nanocomposite material system composed of CuFe2O4 and CuO semiconductor particles to produce hydrogen by electrolysis of water. The nanocomposite powder was prepared using the sol-gel method. Techniques of X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, transmission electron microscopy and UV diffuse reflectance analysis were employed to characterize the synthesized products.The results confirmed the formation of CuFe2O4-CuO nanocomposite powder. The hydrogen evolution was successfully observed over the new hetero-system of CuFe2O4-CuO. The electrolysis activity depended on the concentration of CuO in the system. In order to enhance the hydrogen production, we further optimized the composite material versus the concentration of the compounds.

  5. A route for recycling Nd from Nd-Fe-B magnets using Cu melts

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Martina; Gebert, Annett, E-mail: a.gebert@ifw-dresden.de; Stoica, Mihai; Uhlemann, Margitta; Löser, Wolfgang

    2015-10-25

    Phase evolutions in Nd-Fe-B magnet/Cu systems have been explored with regard to Nd recycling. It was demonstrated that large scale phase separation into a ferromagnetic Fe(B)-rich ingot core with α-Fe main phase and a non-magnetic (Cu,Nd)-rich ingot rim takes place upon arc melting with Cu fractions ≥ 21.5 wt.-%. The re-solidification of the Nd{sub 2}Fe{sub 14}B magnet main phase is suppressed. The rim consists of the Cu{sub 2}Nd main phase and CuNd/Cu{sub 4}Nd minority phases in which Al traces from the magnetic material are gathered. Induction melting of such Nd-Fe-B/Cu mixtures can support the separation of these phase regions with very sharp boundaries. Main features of liquid phase separation and microstructure evolution have been interpreted on the basis of Nd-Fe-Cu phase diagram data. The key advantage with respect to Nd recycling from Nd-Fe-B permanent magnet scrap is the substantial accumulation of Nd in the (Cu,Nd)-rich region of the phase separated solidified specimen, which can be easily detached from the Fe-rich part by mechanical-magnetic treatments. Such portions contained up to ∼44 wt.-% Nd (25 at.-%) in first lab-scale experiments. Nd recovery from the (Cu,Nd)-rich fractions is possible by exploiting the large chemical property differences between the reactive rare earths elements and Cu. - Highlights: • phase evolution analysis in Nd-Fe-B magnet/Cu systems with regard to Nd recycling. • Cu ≥ 21 wt.-%, large scale phase separation- Fe(B)-rich ingot core, (Cu,Nd)-rich rim. • high Nd content (∼44 wt.-%) of (Cu,Nd)-rich region, mechanical-magnetic treatments.

  6. A route for recycling Nd from Nd-Fe-B magnets using Cu melts

    International Nuclear Information System (INIS)

    Phase evolutions in Nd-Fe-B magnet/Cu systems have been explored with regard to Nd recycling. It was demonstrated that large scale phase separation into a ferromagnetic Fe(B)-rich ingot core with α-Fe main phase and a non-magnetic (Cu,Nd)-rich ingot rim takes place upon arc melting with Cu fractions ≥ 21.5 wt.-%. The re-solidification of the Nd2Fe14B magnet main phase is suppressed. The rim consists of the Cu2Nd main phase and CuNd/Cu4Nd minority phases in which Al traces from the magnetic material are gathered. Induction melting of such Nd-Fe-B/Cu mixtures can support the separation of these phase regions with very sharp boundaries. Main features of liquid phase separation and microstructure evolution have been interpreted on the basis of Nd-Fe-Cu phase diagram data. The key advantage with respect to Nd recycling from Nd-Fe-B permanent magnet scrap is the substantial accumulation of Nd in the (Cu,Nd)-rich region of the phase separated solidified specimen, which can be easily detached from the Fe-rich part by mechanical-magnetic treatments. Such portions contained up to ∼44 wt.-% Nd (25 at.-%) in first lab-scale experiments. Nd recovery from the (Cu,Nd)-rich fractions is possible by exploiting the large chemical property differences between the reactive rare earths elements and Cu. - Highlights: • phase evolution analysis in Nd-Fe-B magnet/Cu systems with regard to Nd recycling. • Cu ≥ 21 wt.-%, large scale phase separation- Fe(B)-rich ingot core, (Cu,Nd)-rich rim. • high Nd content (∼44 wt.-%) of (Cu,Nd)-rich region, mechanical-magnetic treatments

  7. Theory of singlet-ground-state magnetism. Application to field-induced transitions in CsFeCl3 and CsFeBr3

    DEFF Research Database (Denmark)

    Lindgård, P.-A.; Schmid, B.

    1993-01-01

    In the singlet ground-state systems CsFeCl3 and CsFeBr3 a large single-ion anisotropy causes a singlet ground state and a doubly degenerate doublet as the first excited states of the Fe2+ ion. In addition the magneteic interaction is anisotropic being much larger along the z axis than perpendicular...... to it. Therefore, these quasi-one-dimensional magnetic model systems are ideal to demonstrate unique correlation effects. Within the framework of the correlation theory we derive the expressions for the excitation spectrum. When a magnetic field is applied parallel to the z axis both substances have...

  8. Thermal Stability of CoFe/Cu/CoFe/IrMn Top Spin Valve

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guang-Hong; WANG Yin-Gang; QI Xian-Jin

    2009-01-01

    We present a study of thermal stability of the top spin valve with a structure of seed Ta (5nm)/Co75Fe25 (5nm)/Cu (2.5nm)/Co75Fe25n (5nm)/Ir20 Mn80 (12nm)/cap Ta (8nm) deposited at room temperature by magnetron sputtering. A vibrating sample magnetometer fixed with a heater was used to record the magnetic hysteresis loops at variational temperatures and x-ray diffraction was performed to characterize the structure of the multilayer.The exchange field Hex and the coercivity of the pinned CoFe layer Hcp decrease monotonically with increasing temperature.The coercivity of the free CoFe layer Hcf in the spin valve shows a maximum at 498K.The temperature dependences of Hex,Hcp and Hcf have also been discussed.

  9. Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu nanowires

    Indian Academy of Sciences (India)

    R S Liu; S C Chang; I Baginskiy; S F Hu; C Y Huang

    2006-07-01

    Highly ordered composite nanowires with multilayer Ni/Cu and NiFe/Cu have been fabricated by pulsed electrodeposition into nanoporous alumina membrane. The diameter of wires can be easily varied by pore size of alumina, ranging from 30 to 100 nm. The applied potential and the duration of each potential square pulse determine the thickness of the metal layers. The nanowires have been characterized by transmission electron microscopy (TEM), magnetic force microscopy (MFM), and vibrating sample magnetometer (VSM) measurements. The MFM images indicate that every ferromagnetic layer separated by Cu layer was present as single isolated domain-like magnet. This technique has potential use in the measurement and application of magnetic nanodevices.

  10. Atom probe study of Cu-segregation in thermal aging of binary Fe-Cu alloys

    International Nuclear Information System (INIS)

    Fe-Cu binary alloy is commonly used as a prototype model alloy for Pressurized Water Reactor (PWR) pressure vessel steels, especially for the study of radiation damage. This is because of the fact that Cu is one of the main solutes, segregation of which is known to cause major embrittlement in reactor pressure vessel (RPV) steels under nuclear radiation. Interestingly, similar solute segregation is often noticed in case of radiation-free long-term thermal aging experiments as well. Therefore, thermal aging experiment which is considerably simpler can be effectively utilized to study the solute segregation behaviour and emulate radiation-induced damage. With this objective, a series of binary Fe-Cu alloys with Cu concentration varying from 0.1 at. % - 1.4 at. % were prepared by vacuum arc melting. They were subsequently cold-rolled, followed by homogenization at 800 C and water quenching. The homogenized samples were then aged at 500 C for the following different durations: 1, 3, 5, 8, 25, 50 and 100 h. 3DAP is an indispensable tool to study solute segregation at this length scale, and the current study will present the results of a detailed 3DAP investigation of the evolution of the thermal damage in these binary prototype alloys. (author)

  11. Magnetoresistance of electrodeposited NiFeCu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Esmaili, S., E-mail: esmaili@shirazu.ac.ir [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Bahrololoom, M.E. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Peter, L. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary)

    2012-01-01

    NiFeCu alloy films were electrodeposited from baths containing nickel sulfate and/or nickel sulfamate. All samples were pulse plated in the potentiostatic mode. The room temperature magnetoresistances of the films were measured showing anisotropic magnetoresistances up to 1.5%. The anisotropic magnetoresistances increased with the addition of sulfamic acid to the sulfate bath. Samples deposited from the bath with high sulfamate concentration showed a giant magnetoresistance behavior. To characterize the films, scanning electron microscopy and X-ray diffraction were used.

  12. Cu-Ni-Fe anodes having improved microstructure

    Science.gov (United States)

    Bergsma, S. Craig; Brown, Craig W.

    2004-04-20

    A method of producing aluminum in a low temperature electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten electrolyte having alumina dissolved therein in an electrolytic cell containing the electrolyte. A non-consumable anode and cathode is disposed in the electrolyte, the anode comprised of Cu--Ni--Fe alloys having single metallurgical phase. Electric current is passed from the anode, through the electrolyte to the cathode thereby depositing aluminum on the cathode, and molten aluminum is collected from the cathode.

  13. Damping capacity of nanoquasicrystalline Al-Cu-Fe materials

    Energy Technology Data Exchange (ETDEWEB)

    Ustinov, A I [E O Paton Electric Welding Institute, 11 Bozhenko Str., Kyiv 03680 (Ukraine); Polishchuk, S S; Skorodzievskii, V S; Bliznuk, V V [G V Kurdyumov Institute of Metal Physics, 36 Vernadsky Str., Kyiv 03142 (Ukraine)], E-mail: polis7@yandex.ru

    2008-02-15

    An influence of the grain size of quasicrystalline Al-Cu-Fe materials (QCs) on their damping capacity at the alternate loading has been investigated in the strain amplitude range of 1.25x10{sup -4} and in the temperature range 20-350 deg. C. It has been established that damping capacity of the nanometer-sized QCs at heating is essentially higher than that of submicron-sized ones. Logarithmic decrement of the QCs is found to increase progressively in whole strain amplitude range as temperatures go higher than some threshold value. Possible mechanisms of dissipation of mechanical energy in nanometer-sized QCs at elevated temperatures are discussed.

  14. Magnetization reversal of Fe ultrathin film on Cu (100)

    Institute of Scientific and Technical Information of China (English)

    He Wei; Zhan Qing-Feng; Wang De-Yong; Chen Li-Jun; Cheng Zhao-Hua

    2008-01-01

    The magnetization reversal of Fe/Cu(100) ultrathin films grown at room temperature is investigated by using an in situ magneto-optical Kerr effect polarimcter with a magnet that can rotate in a plane of incidence.There occur spin reorientation transitions from out-of-plane to in-plane magnetizations in 8 and 12 monolayers (ML) thick iron films.The coercive fields axe observed to be proportional to the reciprocal of the cosine with respect to the easy axis,suggesting that the domain-wall displacement plays a main role in the magnetization reversal process.

  15. Induced anisotropy in nanocrystalline FeCuNbSiB

    International Nuclear Information System (INIS)

    The kinetics of induced anisotropy Kind was studied in nanocrystalline Fe73.5Cu1Nb3Si13.5B9, as well as in the amorphous precursor and in amorphous Fe78B13Si9. The nanocrystalline alloy was produced from the precursor by annealing at 813 K for 1 h and possessed an average FeSi grain size of 13 nm, as determined from x-ray diffraction. Annealing in a 0.2 T field at 723--773 K, above Tc of the amorphous phase, resulted in low values of Kind. The data were compared to the micromagnetic theory of Kronmueller to determine activation energy spectra. Kind for the nanocrystalline alloy is well described by this theory, however, with an activation energy spectrum that is much narrower than for the amorphous alloys. The limiting value of the anisotropy is K∞ ∼ 13 J/m3 consistent with that expected for the anisotropy in Fe-20at%.Si with the DO3 structure

  16. Electromagnetic properties of Fe53Ni47 and Fe53Ni47/Cu granular composite materials in the microwave range

    Science.gov (United States)

    Massango, Herieta; Tsutaoka, Takanori; Kasagi, Teruhiro

    2016-09-01

    The electromagnetic proprieties of Fe53Ni47 granular composite materials and Fe53Ni47/Cu hybrid granular composites have been studied by measuring the relative complex permeability and permittivity spectra as well as the ac electrical conductivity. In the Fe53Ni47 composite, the variation of the ac conductivity at 1 kHz with the particle volume content shows an insulator–metal transition at the percolation threshold at 61 vol% particle content. A negative permeability spectrum due to the magnetic resonance in Fe53Ni47 particles was observed in the 85 vol% composite. Meanwhile, the negative permittivity spectrum caused by the plasmoinc state of the percolated Fe53Ni47 particle clusters appears at 90 vol%. The Fe53Ni47/Cu hybrid composite containing 85 vol% of Fe53Ni47/Cu hybrid particle as filers shows the percolative metallic properties; the ac conductivity increases with increasing the Cu particle volume fraction in the Fe53Ni47/Cu particle system. The negative permittivity spectrum appears above the Cu particle volume fraction of 0.16; the double negative characteristic was observed at that of 0.20 and 0.24 hybrid composites in the frequency range from 300 MHz to 1.8 GHz in the absence of the external magnetic field.

  17. The tunable quantum spin ladder Cu(Qnx)(Cl{sub (1−x)}Br{sub x}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Povarov, K.Yu., E-mail: povarovk@phys.ethz.ch [Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich (Switzerland); Lorenz, W.E.A. [Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich (Switzerland); Xiao, F.; Landee, C.P. [Department of Physics, Clark University, Worcester, MA 01610 (United States); Krasnikova, Y. [P.L. Kapitza Institute for Physical Problems RAS, 119334, Moscow (Russian Federation); Moscow Institute for Physics and Technology, 141700 Dolgoprudny (Russian Federation); Zheludev, A. [Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich (Switzerland)

    2014-12-15

    We report magnetic, specific heat and ESR measurements on a series of S=1/2 spin ladder compounds Cu(Qnx)(Cl{sub (1−x)}Br{sub x}){sub 2}. Down to T=2 K all the observables can be described by the spin ladder model with about 1% of S=1/2 impurities in the background, which are present even in a nominally pure Cu(Qnx)Cl{sub 2} and Cu(Qnx)Br{sub 2}, for the whole range of 0≤x≤1. We extract ladder exchange constants J{sub l}(x) and J{sub r}(x) as well as the gap value Δ(x) by comparing the experimental data to quantum Monte-Carlo simulations. As the ESR measurements show the g-factor of impurities to be precisely equal to g-factor of the ladder spins, we suppose the impurities to be the consequence of structural defects resulting in broken ladder ends. - Highlights: • A family of isostructural spin-ladder compounds was investigated. • A variation in exchange parameters with the degree of chemical substitution was found. • A small amount of paramagnetic spins was attributed to structural defects in a ladder.

  18. Magnetic Torque Studies of π-d System κ-(BDH-TTP)2FeX4 (X = Br, Cl)

    Science.gov (United States)

    Sugii, Kaori; Takai, Kazuyuki; Tsuchiya, Satoshi; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Wada, Atsushi; Ichikawa, Shun; Yamada, Jun-ichi; Enoki, Toshiaki

    2014-02-01

    Systematic measurements of the magnetic torque of organic π-d conductors κ-(BDH-TTP)2FeX4 (X = Br, Cl) have been performed to investigate the magnetic properties. The Fe 3d spins of both salts show antiferromagnetic (AF) orders at low temperatures. A simple two-sublattice model is found to well reproduce the essential features of the torque data in the AF states. The exchange interaction and anisotropic parameter of the ligand field obtained by the simulations are consistent with previous experimental results.

  19. Corrosion behaviour of Al-Cu-Fe alloys containing a quasicrystalline phase

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen-Saarivirta, Elina; Tiainen, Tuomo

    2004-06-15

    Corrosion of quasicrystalline and related crystalline phases coexisting in Al-Cu-Fe alloys with the compositions of Al{sub 60}Cu{sub 27.5}Fe{sub 12.5}, Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}, Al{sub 65}Cu{sub 20}Fe{sub 15} and Al{sub 67.5}Cu{sub 20}Fe{sub 12.5} was studied in saline, acidic, neutral and basic solutions. The corrosion behaviour of the alloys was explored by potentiodynamic polarisation experiments, while the microstructural studies by X-ray diffraction and scanning electron microscopy yielded information on the phase structure and its changes as a result of the polarisation experiments. The results of the study indicated that the composition and relative amount of phases present in Al-Cu-Fe alloys are the key parameters defining the corrosion behaviour of the alloy. In saline solutions, the corrosion potentials were in the range where a homogeneous dissolution of the alloy, followed by a redeposition of Cu, took place, the corrosion rate being mainly determined by the amount of Cu-rich phases present in the structure. In acidic solutions, the Cu-rich phases remained untouched by corrosion, whereas phases containing less Cu were susceptible to corrosion. In neutral and basic solutions, oxidation was the primary surface reaction. However, Cu was found to introduce pores into the oxide layer and Fe to inhibit the oxidation process. Therefore, in neutral and basic solutions, the quasicrystalline phase, with intermittent Cu and Fe contents with respect to other phases present in the Al-Cu-Fe alloys studied, showed the best corrosion performance.

  20. Corrosion behaviour of Al-Cu-Fe alloys containing a quasicrystalline phase

    International Nuclear Information System (INIS)

    Corrosion of quasicrystalline and related crystalline phases coexisting in Al-Cu-Fe alloys with the compositions of Al60Cu27.5Fe12.5, Al62.5Cu25Fe12.5, Al65Cu20Fe15 and Al67.5Cu20Fe12.5 was studied in saline, acidic, neutral and basic solutions. The corrosion behaviour of the alloys was explored by potentiodynamic polarisation experiments, while the microstructural studies by X-ray diffraction and scanning electron microscopy yielded information on the phase structure and its changes as a result of the polarisation experiments. The results of the study indicated that the composition and relative amount of phases present in Al-Cu-Fe alloys are the key parameters defining the corrosion behaviour of the alloy. In saline solutions, the corrosion potentials were in the range where a homogeneous dissolution of the alloy, followed by a redeposition of Cu, took place, the corrosion rate being mainly determined by the amount of Cu-rich phases present in the structure. In acidic solutions, the Cu-rich phases remained untouched by corrosion, whereas phases containing less Cu were susceptible to corrosion. In neutral and basic solutions, oxidation was the primary surface reaction. However, Cu was found to introduce pores into the oxide layer and Fe to inhibit the oxidation process. Therefore, in neutral and basic solutions, the quasicrystalline phase, with intermittent Cu and Fe contents with respect to other phases present in the Al-Cu-Fe alloys studied, showed the best corrosion performance

  1. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.;

    2009-01-01

    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly...... by the spin Luttinger-liquid state of the ladder subunits. We determine directly the order parameter (transverse magnetization), the ordering temperature, the spin structure, and the critical exponents around the transition. We introduce a minimal microscopic model for the interladder coupling and calculate...

  2. Structure and thermodynamic properties of a weakly-coupled antiferromagnetic spin-1/2 chain compound (C5H12N)CuBr3

    OpenAIRE

    Pan, B. Y.; Wang, Y.; Zhang, L J; Li, S. Y.

    2013-01-01

    Single crystals of a metal organic complex \\ce{(C5H12N)CuBr3} (\\ce{C5H12N} = piperidinium, pipH for short) have been synthesized and the structure was determined by single-crystal X-ray diffraction. \\ce{(pipH)CuBr3} crystallizes in the monoclinic group $C$2/$c$. Edging-sharing \\ce{CuBr5} units link to form zigzag chains along the $c$ axis and the neighboring Cu(II) ions with spin-1/2 are bridged by bi-bromide ions. Magnetic susceptibility data down to 1.8 K can be well fitted by the Bonner-Fi...

  3. Kinetic study of the annealing reactions in Cu-Ni-Fe alloys; Estudio cinetico de las reacciones de recocido en aleaciones de Cu-Ni-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E.

    2014-07-01

    The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi{sub 3} phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi{sub 3} phase. (Author)

  4. Compressibility of nanostructured Fe-Cu materials prepared by mechanical milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J.S.; Gerward, Leif;

    1999-01-01

    The compressibility of nanostructured Fe-Cu materials prepared by mechanical milling has been investigated by in-situ high-pressure x-ray diffraction using synchrotron radiation. It is found that the bulk modulus of both fcc-Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable...

  5. Electronic structure of nanosized bcc Cu precipitates in Fe-Cu alloys studied by positron 2D-ACAR

    International Nuclear Information System (INIS)

    Based on the finding with the use of the coincidence Doppler measurements that the nanosized Cu precipitates are coherently embedded in the Fe-Cu matrix alloy, taking a bcc structure and acting as efficient positron traps, we measured 2D-ACARs of carefully grown and heat treated single crystals of Fe-Cu. We found that the precipitates have a Fermi surface with 12 necks touching the {110} Bragg planes of the bcc Brillouin zone, which contrasts distinctly with that of the bulk Cu with 8 necks touching the {111} Bragg planes of the fcc Brillouin zone. The 3 dimensional momentum reconstruction of the 2D-ACAR data showed that the Fermi surface cutoff of the Cu precipitates is blurred considerably as compared with that of bulk fcc Cu, suggesting a marked size effect in the momentum distribution. (orig.)

  6. Penentuan Kualitas Aluminium Ingot Dengan Pengukuran Kadar Fe, Si Dan Cu, Menggunakan Optical Emission Spectrometer

    OpenAIRE

    Putra, Andika

    2012-01-01

    Based on the research results were found: for the first aluminum has a purity of Al =99,81% (Fe 0,1445%, Si 0,0473% and Cu 0,0003%), the second almunium has purity of Al = 99.92%, (Fe 0,0521%, Si 0,0335% and Cu 0,0002%),the third aluminum has purity of Al = 99.81%,(Fe 0,1475%, Si 0,0442% and Cu 0,0002%), the fourth alumunium has purity of Al = 99.91% , (Fe 0,0463%, Si 0,0373% and Cu = 0,0001%), the fifth aluminum has purity of Al = 99.82%, (Fe 0,1406%, Si 0,0421% and Cu 0,0003%), t...

  7. Study of Microstructure and Magnetic Properties of Pr-Fe-B-Cu Permanent Magnets by Hot Deformation

    Institute of Scientific and Technical Information of China (English)

    陈秀云; 姜忠良; 高天明; 吴严; 杨昌平; 朱静

    2002-01-01

    The relationship between the microstructures and magnetic properties of rare earth cast permanent Pr-Fe-B-Cu alloys by hot deformation was studied. Fine and well-aligned column grains can be obtained by using a proper solidification mould with a high cooling rate. The soft magnetic phase α-Fe can be removed during proper annealing treatment. Hot pressing can produce the anisotropy and refine the grain size, so that the magnetic properties are greatly improved. The technique has the advantages of simple processing, low cost and high benefit, compared with the common sintering processing. Under the condition of the deformation temperature of 1073 K, 90% strain and strain rate of 40×10-3 s-1, the magnetic properties obtained are: Br=1.05 T, i Hc=955 kAm-1, (BH)max=207 kJ*m-3.

  8. 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.

  9. On the concentration and separation of the trace-elements fe, cu, zn, mn, pb, mo and co : Paper chromatography

    NARCIS (Netherlands)

    Erkelens, P.C. van

    1961-01-01

    Paper chromatographic separations are described by which the minor constituents of biological ashes are separated either into: (Pb) - Mn - Co - (Pb) - Cu - Fe, Mo, Zn; or into: Cu, Mn, Co - Pb - Fe - Mo - Zn.

  10. Sliding Friction of Al-Cu-Fe-B Quasicrystals

    Institute of Scientific and Technical Information of China (English)

    Xiying ZHOU; Peiyao LI; Junming LUO; Shiqiang QIAN; Jianhua TONG

    2004-01-01

    Dry sliding friction between the Al59Cu25.5Fe12.5B3 quasicrystals (QCs)/coating of the diamond-like carbon (DLC) was carried out by self-made tribometer under different conditions. The influences of four parameters (temperature, sliding velocity, applied load, atmosphere) on friction and wear of quasicrystal surface were studied. Microstructure of quasicrystal, morphology of worn surface, and wear debris were observed by scanning electron microscopy (SEM).The results showed that for QCs, the friction coefficient and roughness of worn surface were influenced by the parameters, especially greatly by the temperature. With rise of the applied load and sliding velocity, the friction coefficient decreased. The dominant wear mechanism at 350℃ was delamination for QCs. The cracks formed on the worn surface during the friction. Moreover, phase transformation was not observed on worn surface of QCs at 350℃. All the results are discussed and explained.

  11. Comparative study of radiation damage accumulation in Cu and Fe

    Science.gov (United States)

    Caturla, M. J.; Soneda, N.; Alonso, E.; Wirth, B. D.; Díaz de la Rubia, T.; Perlado, J. M.

    2000-01-01

    Bcc and fcc metals exhibit significant differences in behavior when exposed to neutron or heavy ion irradiation. Transmission electron microscopy (TEM) observations reveal that damage in the form of stacking fault tetrahedra (SFT) is visible in copper irradiated to very low doses, but that no damage is visible in iron irradiated to the same total dose. In order to understand and quantify this difference in behavior, we have simulated damage production and accumulation in fcc Cu and bcc Fe. We use 20 keV primary knock-on atoms (PKAs) at a homologous temperature of 0.25 of the melting point. The primary damage state was calculated using molecular dynamics (MD) with empirical, embedded-atom interatomic potentials. Damage accumulation was modeled using a kinetic Monte Carlo (kMC) algorithm to follow the evolution of all defects produced in the cascades. The diffusivities and binding energies of defects are input data for this simulation and were either extracted from experiments, the literature, or calculated using MD. MD simulations reveal that vacancy clusters are produced within the cascade core in the case of copper. In iron, most of the vacancies do not cluster during cooling of the cascade core and are available for diffusion. In addition, self-interstitial atom (SIA) clusters are produced in copper cascades but those observed in iron are smaller in number and size. The combined MD/kMC simulations reveal that the visible cluster densities obtained as a function of dose are at least one order of magnitude lower in Fe than in Cu. We compare the results with experimental measurements of cluster density and find excellent agreement between the simulations and experiments when small interstitial clusters are considered to be mobile as suggested by recent MD simulations.

  12. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two sepa- rated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respec- tively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) drop- lets with the same size.

  13. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    DAI FuPing; CAO ChongDe; WEI BingBo

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two separated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respectively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) droplets with the same size.

  14. Template-grown NiFe/Cu/NiFe nanowires for spin transfer devices.

    Science.gov (United States)

    Piraux, Luc; Renard, Krystel; Guillemet, Raphael; Matéfi-Tempfli, Stefan; Matéfi-Tempfli, Maria; Antohe, Vlad Andrei; Fusil, Stéphane; Bouzehouane, Karim; Cros, Vincent

    2007-09-01

    We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena. The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications. PMID:17715984

  15. A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

    Science.gov (United States)

    A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

  16. Investigation of magnetic structure on (C5H12N)CuBr3 system on the basis of DFT study and orbital interaction

    Science.gov (United States)

    Lee, Changhoon; Hong, Jisook; Shim, Ji Hoon; Pohang Univ of Sci; Tech Team

    2015-03-01

    The (C5H12N)CuBr3 compound crystallizes in the monoclinic group C2/c. Magnetic susceptibility data down to 1.8 K can be well fitted for the antiferromagnetic spin-1/2 chain, giving the intrachain magnetic coupling constant Jintra ~ -17 K. At zero field, (pipH)CuBr3 shows 3D order below TN = 1.68 K. Calculated by the mean-field theory, the interchain coupling constant Jinter = - 0.91 K is obtained and the ordered magnetic moment is about 0.23 μB. However, the interchain interaction should be strong unlike experimental observation. From the analysis of local structure, the Jinter spin dimer show the possibility of good orbital overlap via Cu-O...O-Cu path in which angle for Cu-O...O-Cu is 161° indicating strong interchain interaction via Cu-O...O-Cu path. The magnetic structure of (C5H12N)CuBr3 system in terms of orbital interaction could anticipated by two-leg spin ladder which such spin ladders interact ferromagnetically to form ladder. In this study, we evaluated spin exchange interactions of (pipH)CuBr3 based on DFT calculations to find the magnetic structure of this system. As a consequence, the Jinter interaction is strong and the magnetic structure of this system, indeed, is described by two-leg spin ladder. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2060341)

  17. Nanometer Stripe Microstructure of Supersaturated Solid Solution in Fe-Cu Alloy

    Institute of Scientific and Technical Information of China (English)

    REN Hui-ping; WANG Hai-yan; LIU Zong-chang; AN Zhi-guo

    2007-01-01

    Strengthening due to precipitation of Cu in the α-Fe matrix is an important phenomenon utilized in the design of HSLA steels. In the present work, the microstructure of supersaturated solid solution in Fe-1.18%Cu binary alloy was investigated by means of high resolution electron microscopy. The results indicated that the solid solution was heterogeneous, there were lots of Cu atom clusters, which consisted of diffractive stripe microstructure similar to twin crystal. Orientation deviation was observed between two (110)α planes in diffractive stripes, which results in light and shade contrast. Furthermore, formation mechanisms of the nanometre stripe microstructure were discussed in terms of the interaction of Cu and Fe atoms in the Fe-Cu binary alloys.

  18. Synchrotron X—Ray Study on Structures of Ni80Fe20/Cu Superlattices

    Institute of Scientific and Technical Information of China (English)

    杨涛; 麦振洪; 赖武彦; 吴忠华; 王德武; XUMing; 罗光明; 柴春林

    2001-01-01

    We have shown that,in contrast to the results in the literature,the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element(Cu).The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak.Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices.Upon annealing,the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.

  19. Direct Measurement of the Metastable Liquid Miscibility Gap in Fe-Co-Cu Ternary Alloy System

    Institute of Scientific and Technical Information of China (English)

    CAO Chong-De; Georg P.G(O)RLER

    2005-01-01

    @@ The metastable liquid-liquid phase separation in undercooled Fe-Co-Cu ternary alloy melts (XCu = 0.10-0.84;XCo:XFe = 1:3,1:1 and 3:1) is investigated by differential thermal analysis in combination with glass fluxing technique. In almost every case, the undercooling of the homogeneous alloy melt was sufficient to reach the boundary line of the submerged miscibility gap. The differential-thermal-analysis signals indicate that this separation into a (Fe, Co)-rich liquid phase L1 and a Cu-rich liquid L2 is exothermic and proceeds until the rapid solidification of the L1 phase occurs. At a given Cu concentration and with the increase of Co content, the phase separation temperatures decrease monotonically between the corresponding values of the boundary systems Fe-Cu and Co-Cu. The boundary lines of the miscibility gap, which are determined for the three quasi-binary cross-sections of the (Fe, Co)-Cu alloy system, show remarkably flat domes. The occurrence of the liquid phase separation shows an evident influence on the subsequent γ-Fe(Co, Cu)→α-Fe(Co, Cu) solid phase transformation.

  20. Structural evolutions of the mechanically alloyed Al70Cu20Fe10 powders

    Indian Academy of Sciences (India)

    Musa Göğebakan; Bariş Avar

    2011-10-01

    Elemental mixtures of Al, Cu, Fe powders with the nominal composition of Al70Cu20Fe10 were mechanically alloyed in a planetary ball mill for 80 h. Subsequent annealing of the as-milled powders were performed at 600–800°C temperature range for 4 h. Structural characteristics of the mechanically alloyed Al70Cu20Fe10 powders with the milling time and the heat treatment were investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and differential thermal analysis (DTA). Mechanical alloying of the Al70Cu20Fe10 did not result in the formation of icosahedral quasicrystalline phase (i-phase) and a long time milling resulted in the formation of -Al(Cu,Fe) solid solution phase (-phase). The i-phase was observed only for short-time milled powders after heat treatment above 600°C. The -phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation indicated that a suitable technique to obtain a large amount of quasicrystalline powders is to use a combination of short-time milling and subsequent annealing.

  1. Adsorption and catalytic combustion of ARB on CuO-Fe2O3

    Institute of Scientific and Technical Information of China (English)

    WU Rongcheng; QU Jiuhui; HE Hong; YU Yunbo

    2003-01-01

    CuO-Fe2O3 composite material with strong magnetism and a large surfacearea is prepared by the co-precipitate method. Its adsorption properties towards Acid Red B (ARB) and the regeneration by catalytic combustion of organic compounds have been studied. The results show that the prepared CuO-Fe2O3 composite is an excellent adsorbent for ARB adsorption at acid condition. The presence of Cl- has no effect on ARB adsorption. But the can inhibit ARB adsorption. After being recovered by the magnetic separation method, the adsorbent can be regenerated by catalytic oxidation of absorbate at 300℃ in air atmosphere. The combustion reactions of ARB in the presence or absence of CuO-Fe2O3 are studied by in situ diffuse reflection FTIR. The results indicate that, in the presence of CuO-Fe2O3, the degradation temperature is significantly lowered by the catalysis of CuO-Fe2O3, and ARB can be oxidized completely without volatile organic compound by-product; in comparison, in the absence of CuO-Fe2O3, the temperature needed for oxidation of ARB is higher and the reaction is incomplete with some N-containingharmful compounds produced. The reusability of CuO-Fe2O3 is also studied in successive seven adsorption-regeneration cycles.

  2. Dechlorination of carbon tetrachloride by the catalyzed Fe-Cu process

    Institute of Scientific and Technical Information of China (English)

    XU Wen-ying; GAO Ting-yao

    2007-01-01

    The electrochemical reduction characteristics of carbon tetrachloride (CT) were investigated using cyclic voltammetry in this study. In addition, the difference in reduction mechanisms of CT between Master Builders' iron and the catalyzed Fe-Cu process was discussed. The results showed that CT was reduced directly on the surface of copper rather than by atomic hydrogen produced at the cathode in the catalyzed Fe-Cu process. The reduction was realized largely by atomic hydrogen in Master Builders' iron. The entire CT in 350 ml aqueous solution with 320 mg/L was reduced to trichloromethane and dichloromethane in 2.25 h when 100 g of scrap iron with Fe/Cu ratio of 10:1 (w/w) were used. Moreover, the reduction rate slowed with time. CT could be reduced at acidic, neutral and alkaline pH from solution by Fe-Cu bimetallic media, but the mechanisms were different. The degradation rate was not significantly influenced by pH in the catalyzed Fe-Cu process; in Master Builders' iron it clearly increased with decreasing pH. The kinetics of the reductions followed pseudo-first order in both cases. Furthermore, the reductions under acidic conditions proceeded faster than that under the neutral and alkaline conditions. The catalyzed Fe-Cu process was superior to Master Builders' iron in treating CT-containing water and this advantage was particularly noticeable under alkaline conditions. The reduction was investigated in the cathode (Cu) and anode (Fe) compartments respectively, the results showed that the direct reduction pathway played an important role in the reduction by the catalyzed Fe-Cu process. The catalyzed Fe-Cu process is of practical value.

  3. Novel Fluorescent Chemosensors Based on Tryptophan Unit for Cu2+ and Fe3+ in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    CHENG Peng-fei; XU Kuo-xi; YAO Wen-yong; KONG Hua-jie; KOU Li; MA Xiao-dan; WANG Chao-jie

    2013-01-01

    We reported four fluorescent chemosensors containing tryptophan units.The fluorescence spectrum titration experiments suggest that chemosensors 1,2,3 and 4 are highly selective for Cu2+ and Fe3+ over Li+,Na+,K+,Co2+,Zn2+,Ni2+,Hg2+ and Cr3+ via forming complexes with Cu2+ or Fe3+,which is confirmed by dramatical quench of fluoreseence in aqueous solution at pH 7.4,thus making all the chemosensors suitable for Cu2+ and Fe3+ fluorescent sensors.

  4. Conversion of syngas to higher alcohols over Cu-Fe-Zr catalysts induced by ethanol

    Institute of Scientific and Technical Information of China (English)

    Hongtao Zhang; Xiaomei Yang; Lipeng Zhou; Yunlai Su; Zhongmin Liu

    2009-01-01

    Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method,it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol,the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.

  5. A General and Efficient CuBr2-Catalyzed N-Arylation of Secondary Acyclic Amides

    Institute of Scientific and Technical Information of China (English)

    王满刚; 于华; 尤心稳; 吴军; 商志才

    2012-01-01

    A general and efficient Cu(II)-catalyzed cross-coupling method is reported for the preparation of acyclic tertiary amides. Generally moderate to excellent yields and functional group tolerance were obtained with secondary acyclic amides and aryl halides as substrates in toluene.

  6. Kinetic analysis of the factors limiting the output power of the Ne-CuBr UV laser

    Institute of Scientific and Technical Information of China (English)

    Mao Bang-Ning; Pan Bai-Liang; Chen Li; Wang Ya-Juan; Yao Zhi-Xin

    2009-01-01

    The parametric optimization of the Ne-CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model.Consistent characteristics of the optimization process are obtained by comparing with the experimental results.Simulation results show that neon ions come into being along with considerable depletion of the ground-state copper atoms.And the optimization of the discharge tube diameter is the tradeoff between the specific output photon density and the total active volume.Both the optimal neon gas pressure and the optimal reservoir temperature result from the balance between the neon ion density and the ground-state copper atom density to arrive at a maximum of their product.

  7. Crystal Structure and Physical Properties of π--d System κ-(BDH-TTP)2FeBr4

    Science.gov (United States)

    Sugii, Kaori; Takai, Kazuyuki; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Wada, Atsushi; Ichikawa, Shun; Yamada, Jun-ichi; Mori, Takehiko; Enoki, Toshiaki

    2013-05-01

    The structure and physical properties of metallic magnetic conductor κ-(BDH-TTP)2FeBr4 (BDH-TTP: 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene) are investigated. It has a layered structure of BDH-TTP donor sheets extended along the ac-plane, which are sandwiched by FeBr4 anion sheets. The π electrons on the BDH-TTP sheets show simple metallic behavior down to 30 mK. The magnetic susceptibility obeys the Curie--Weiss law mainly associated with the Fe3+ d spins (S = 5/2), and indicates the presence of an anitiferromagnetic (AF) transition at TN = 3.9 K. In the AF state, a steep S-shaped increase of the magnetization at 1.5 T (HSF) in the field parallel to the a-axis (H\\parallel a) is found, which is ascribed to a spin-flop transition. In addition, the magnetization curves for H\\parallel b and H\\parallel c show an inflection point at Hc = 3.1 T, suggesting the spin canting configuration in the bc-plane. A possible AF spin structure based on the magnetization data and molecular orbital calculations features triangular lattice consisting of the Fe d electron spins and the donor π electron spins. Possible origins responsible for the spin canting, Dzyaloshinskii--Moriya interaction, spin frustration effect, and anisotropy of the ligand field, are discussed. A steep decrease of the magnetoresistance in the AF state observed at HSF for H\\parallel a proves that the strong π--d interaction seriously affects the electron transport in the donor system. An anomalous broadening of the ESR linewidth in the critical region above TN is suggestive of the development of a magnetic short range order, for which the low-dimensionality in the spin system is responsible.

  8. EXAFS STUDY OF THE SHORT RANGE STRUCTURE OF NANOCRYSTALLINE BCC-Fe80Cu20 SOLID SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Yang; X.J. Bai; T.C. Kuang; G.M. Wang; S. Q. Wei

    2002-01-01

    The structure of bcc-Fe80 Cu2o solid solution produced by mechanical alloying of theelemental bcc-Fe and fcc-Cu powders has been studied using X-ray diffraction and theextended X-ray absorption fine structure (EXAFS) techniques. The disappearance ofelemental Fe and Cu X-ray diffraction (XRD) peaks and the presence of bcc structuralXRD peaks illustrate the formation of a nanocrystalline single-phase bcc-Fe80 Gu20solid solution. From the EXAFS results, the clear observation of Cu atoms taking onbcc coordination in the solid solution and Fe atoms remaining bcc structure furtherverifies the reality of atomic alloying between Fe and Cu atoms and the lattice changeof Cu from fcc to bcc. However, the supersaturated bcc solid solution is not chemicallyuniform, i.e., some regions are rich in Fe atoms and other regions rich in Cu atoms.

  9. Solute redistribution during phase separation of ternary Fe-Cu-Si alloy

    Science.gov (United States)

    Luo, S. B.; Wang, W. L.; Xia, Z. C.; Wu, Y. H.; Wei, B.

    2015-06-01

    Ternary Fe48Cu48Si4 immiscible alloy was rapidly solidified under the containerless microgravity condition inside a drop tube. Liquid phase separation took place in the alloy melt and led to the formation of various segregated structures. The core-shell structure consisting of Fe-rich and Cu-rich zones and the homogenously dispersed structure were the major structural morphologies. Phase field simulation results revealed that the two-layer core-shell was the final structure of liquid phase separation. The solute redistribution of liquid Fe48Cu48Si4 alloy experienced the macroscopic solute distribution induced by liquid phase separation, the secondary phase separation within the separated liquid phases and the solute trapping during rapid solidification. Energy dispersive spectroscopy analysis showed that the solute Si was enriched in the Fe-rich zone whereas depleted in the Cu-rich zone. In addition, both αFe and (Cu) phases in the Fe-rich zone exhibited a conspicuous solute trapping effect. As compared with (Cu) phase, αFe phase had a stronger affinity with solute Si.

  10. Effect of Applied Current Density on Morphological and Structural Properties of Electrodeposited Fe-Cu Films

    Institute of Scientific and Technical Information of China (English)

    Umut Sarac; M. Celalettin Baykul

    2012-01-01

    A detailed study has been carried out to investigate the effect of applied current density on the composition, crystallographic structure, grain size, and surface morphology of Fe-Cu films. X-ray diffraction (XRD) results show that the films consist of a mixture of face-centered cubic (fcc) Cu and body centered cubic (bcc) ~-Fe phases. The average crystalline size of both Fe and Cu particles decreases as the applied current density becomes more negative. Compositional analysis of Fe-Cu films indicates that the Fe content within the films increases with decreasing current density towards more negative values. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to investigate the surface morphology of Fe-Cu films. It is observed that the surface morphology of the films changes from dendritic structure to a cauliflower structure as the applied current density becomes more negative. The surface roughness and grain size of the Fe-Cu films decrease with decreasing applied current density towards more negative values.

  11. Development and Oxidation Behavior of Al-Cu-Fe Quasicrystalline Coating on Ti Alloy

    Institute of Scientific and Technical Information of China (English)

    Fei CAI; Chungen ZHOU; Huibin XU; Shengkai GONG

    2004-01-01

    An oxidation resistant Al-Cu-Fe quasicrystalline coating was fabricated on substrate of Ti alloy by Iow pressure plasma spraying (LPPS) method. As-sprayed Al-Cu-Fe coating has a rapidly solidified lamellar microstructure consisting of quasicrystalline phase and crystalline phase. The formation of quasicrystalline coating is related to the annealing. The results from the oxidation experiments showed that Al-Cu-Fe quasicrystalline coating improved the oxidation resistance of Ti-base alloys. During the oxidation period there is no evident spallation of the coating from the substrate. Oxide formed on the surface of Al-Cu-Fe quasicrystalline coating after oxidation consisted of Al2O3. Oxidation occurs leading to a change of concentration and phase transformation in the coating surface. Selective oxidation of Al transforms the quasicrystalline phase into the phase.

  12. The electrical conductivity characteristics of Fe/Cu nano-scale multilayer materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mathematical model for describing the relationship betweenelectrical conductivity and the thickness of bilayer, ratio of sublayer thickness of a nano-scale multilayer material (MLM) is presented. Fe/Cu MLM was synthesized by electron beam physical vapor deposition (EB-PVD) technique, and the dependence of electrical conductivity of Fe/Cu MLM on the bilayer thickness and ratio of sublayer thickness were investigated. It is shown that the electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness decreases sharply when the thickness of bilayer becomes thinner than 30 nm. When the bilayer thickness is kept constant, the electrical conductivity linearly decreases with the increasing ratio of sublayer thickness. The values of parameters in the model were obtained by fitting the measured results of electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness. It is found that the calculated values agree well with measured ones.

  13. Photocatalytic Characterization of Fe- and Cu-Doped ZnO Nanorods Synthesized by Cohydrolysis

    Directory of Open Access Journals (Sweden)

    Young Rang Uhm

    2013-01-01

    Full Text Available Fe- and Cu-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn, Fe, and Cu nanopowders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60°C for 24 h to obtain the precipitates from the hydrolysis of Zn and dopants (Cu and Fe. The TEM results for ZnO with and without metal doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing doping content, the UV-vis spectra were shifted to a long wavelength and this result indicates that the band gap was changed by the metal doping. The values of phenol degrading Fe- and Cu-doped ZnO by a solar simulator were measured to be 60 and 75%, respectively.

  14. Partial and integral enthalpies of mixing of Cu-Fe-Ti melts at 1873 K

    Science.gov (United States)

    Abdulov, A. R.; Dreval', L. A.; Agraval, P. G.; Turchanin, M. A.

    2009-10-01

    The partial enthalpy of mixing of titanium in Cu-Fe-Ti melts are studied by high-temperature isoperibolic calorimetry at 1873 K in the composition range x Ti = 0-0.6 along three sections with a ratio x Fe / x Cu = 1/3, 1, and 3. The integral enthalpy of mixing of the ternary melts is calculated by integrating the Gibbs-Duhem equation and is described in terms of the Redlich-Kister-Muggianu model. Function Δ H demonstrates negative values over a wide concentration range. The contribution of a ternary interaction to the enthalpy of mixing of Cu-Fe-Ti melts is mainly positive. The first partial enthalpies of mixing of Al, Sn, Si, Y, Zr, Hf, and Ni with Cu-Fe-Ti melts are negative and indicate an increase of the thermodynamic stability of the liquid phase upon the dissolution of these additions.

  15. Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO2 mediated heterogeneous activation of peroxymonosulfate.

    Science.gov (United States)

    Ding, Yaobin; Tang, Hebin; Zhang, Shenghua; Wang, Songbo; Tang, Heqing

    2016-11-01

    Microscaled CuFeO2 particles (micro-CuFeO2) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO2 was of pure phase and a rhombohedral structure with size in the range of 2.8±0.6μm. The micro-CuFeO2 efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO4-), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO2 was observed to be 6.9 and 25.3 times that of micro-Cu2O and micro-Fe2O3, respectively. The enhanced activity of micro-CuFeO2 for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO2 can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu2O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO2 was effective in the studied actual aqueous environmental systems. PMID:27329789

  16. Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

    KAUST Repository

    Ma, Hongbin

    2016-01-01

    In this work, we accurately measure the electrical properties of individual Fe30Co61Cu9/Cu multilayered nanowires using nanomanipulators in in situ scanning electron microscopy to reveal that interfacial transition layers are influential in determining their transport behaviors. We investigate the morphology, crystal structure and chemistry of the Fe30Co61Cu9/Cu multilayered nanowires to characterize them at the nanoscale. We also compare the transport properties of these multilayered nanowires to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed analysis of the electrical data reveals that interfacial transition layers influence the electrical properties of multilayered nanowires and are likely to have a strong impact on the life of nanodevices. This work contributes to a basic understanding of the electrical parameters of individual magnetic multilayered nanowires for their application as functional building blocks and interconnecting leads in nanodevices and nanoelectronics, and also provides a clear physical picture of a single multilayered nanowire which explains its electrical resistance and its source of giant magnetoresistance. © The Royal Society of Chemistry 2016.

  17. Heteropoly acid promoted Cu and Fe catalysts for the selective catalytic reduction of NO with ammonia

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Mossin, Susanne L.; Riisager, Anders;

    2011-01-01

    Cu/TiO2, Fe/TiO2 and heteropoly acid promoted Cu/TiO2, Fe/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD, NH3-TPD, H2-TPR and EPR. The catalysts exhibited only crystalline TiO2 phases with the active metals and promoters in highly dispersed state. The acidic properties...

  18. Microstructural and magnetic characterizations of CoFeCu electrodeposited in self-assembled mesoporous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fortas, G., E-mail: g.fortas@gmail.com [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Haine, N. [Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Sam, S.; Gabouze, N. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Saifi, A. [Université Mouloud Mammeri, laboratoire de physique et de chimie quantique, BP No. 17 RP Hasnaoua Tizi-Ouzou 15000 (Algeria); Ouir, S. [Université Said SDB, Route De Soumaa BP 270, Blida (Algeria); Menari, H. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria)

    2015-03-15

    Self-assembled mesoporous silicon with quasi-regular pore arrangements has been fabricated by the electrochemical anodization process in hydrofluoric acid solution. CoFeCu was electrodeposited in this structure from a bath containing sodium acetate as a complexing agent with a pH value of 5. The effect of current density on the morphology, the structure and the magnetic properties of CoFeCu deposit was studied by SEM, EDS, DRX and VSM. It has been shown that the morphology and structure of samples were strongly influenced by the current density and etching duration. The micrographs show the vertical and branched nanowires and also a discontinuous growth of wires. Further, the growth of a thick layer from the grain boundaries of released CoFeCu wires is produced. The magnetic hysteresis loops demonstrate that the CoFeCu nanowires exhibit easy magnetic axis perpendicular to the PS channels axis when the current density varied from 3 to 10 mA/cm{sup 2}. Nevertheless, they reveal a no magnetic anisotropy of CoFeCu nanostructures deposited only in the outside of porous silicon, probably due to the vanishing the shape anisotropy. - Highlights: • CoFeCu deposit has been electrodeposited on self assembled mesoporous silicon. • SEM observation shows that CoFeCu embedded in Porous silicon channels. • Magnetic measurements show the anisotropy magnetic behavior of CoFeCu nanostructures. • The growth rate of nanowires is enhanced with an increase of current density.

  19. Metastable fcc-Fe film epitaxially grown on Cu(100) single-crystal underlayer

    Science.gov (United States)

    Ohtake, Mitsuru; Shimamoto, Kohei; Futamoto, Masaaki

    2013-05-01

    Fe film of 40 nm thickness is prepared on fcc-Cu(100) single-crystal underlayer at room temperature by ultra-high vacuum molecular beam epitaxy. The film growth and the detailed structure are investigated by reflection high-energy electron diffraction, cross-sectional high-resolution transmission electron microscopy (HR-TEM), and x-ray diffraction (XRD). An Fe single-crystal with metastable fcc structure nucleates on the underlayer. The HR-TEM shows that fcc lattice is formed from the Fe/Cu interface up to the film surface. A large number of misfit dislocations are introduced around the Fe/Cu interface due to an accommodation of lattice mismatch. Dislocations exist up to the film near surface. The lattice constant is estimated by XRD to be a = 0.3607 nm. The film shows a ferromagnetic property, which reflects the property of fcc-Fe crystal with high-spin ferromagnetic state.

  20. Effect of Boron and Cerium on Corrosion Resistance of Cu -Fe -P Alloy

    Science.gov (United States)

    Zou, Jin; Lu, Lei; Lu, De-ping; Liu, Ke-Ming; Chen, Zhi-bao; Zhai, Qi-jie

    2016-03-01

    The effects of B and Ce on the corrosion resistance of Cu-0.22Fe-0.06P alloy were investigated by salt spray and electrochemical tests. The corrosion morphology was studied by scanning electron microscopy. The corrosion products were characterized by energy-dispersive x-ray spectroscopy and x-ray diffraction analysis. The impurity content was determined by inductively coupled plasma mass spectrometry. The conductivity was measured using an eddy current conductivity meter. The grains of Cu-0.22Fe-0.06P alloy were refined by the addition of B and Ce. The electrochemical corrosion process of alloy is retarded due to purification effect of B and Ce. After the addition of a trace amount of B, the corrosion resistance of the alloy decreased. The corrosion resistance of Cu-0.22Fe-0.06P-0.025B-0.05Ce was better than that of Cu-0.22Fe-0.06P-0.025B due to the fact that the purification effect of Ce is better than that of B. The main corrosion products of the Cu-Fe-P alloys in a NaCl solution are Cu2Cl(OH)3 and Cu2O. The addition of trace amounts of B and Ce did not change the components of the corrosion product.

  1. Fe and Co nanostructures embedded into the Cu(100) surface: Self-Organization and magnetic properties

    International Nuclear Information System (INIS)

    The self-organization and magnetic properties of small iron and cobalt nanostructures embedded into the first layer of a Cu(100) surface are investigated using the self-learning kinetic Monte Carlo method and density functional theory. The similarities and differences between the Fe/Cu(100) and the Co/Cu(100) are underlined. The time evolution of magnetic properties of a copper monolayer with embedded magnetic atoms at 380 K is discussed

  2. Overlapping solid solubility in mechanically alloyed Fe-Ni and Fe-Cu

    Science.gov (United States)

    Schilling, P. J.; Palshin, V.; Tittsworth, R. C.; He, J. H.; Ma, E.

    2003-12-01

    Solid solutions formed by mechanical alloying in the negative heat of mixing Fe-Ni system and the positive heat of mixing Fe-Cu system were studied. X-ray absorption near edge structure (XANES) spectroscopy data were analyzed to obtain the phase fractions and phase compositions for various overall compositions across the bcc/fcc two-phase region. For both systems, at each nominal composition of the powder mixture, the two solutions formed both have the same composition as the overall alloy. It is concluded that the two-phase coexistence represents an extended region of overlapping solubility for the two phases, rather than the usual two-phase region or a clear switchover at the concentration where the two phases have the same free energy. In terms of these features, the two binary systems, one with negative heat of mixing and one with positive heat of mixing, behave the same way. The external forcing action of mechanical alloying at low temperatures drives the system toward composition homogenization. There is no stable or metastable equilibrium, and the common tangent construction and lever rule are not applicable. What results is a novel two-phase coexistence which is defined by a region of overlapping solubility, rather than the normal solubility gap. That there can be two polymorphs at each composition even after the long ball-milling treatment represents a new type of steady-state two-phase coexistence that is completely different from the normal two-phase region dictated by thermodynamics.

  3. Overlapping solid solubility in mechanically alloyed Fe-Ni and Fe-Cu

    International Nuclear Information System (INIS)

    Solid solutions formed by mechanical alloying in the negative heat of mixing Fe-Ni system and the positive heat of mixing Fe-Cu system were studied. X-ray absorption near edge structure (XANES) spectroscopy data were analyzed to obtain the phase fractions and phase compositions for various overall compositions across the bcc/fcc two-phase region. For both systems, at each nominal composition of the powder mixture, the two solutions formed both have the same composition as the overall alloy. It is concluded that the two-phase coexistence represents an extended region of overlapping solubility for the two phases, rather than the usual two-phase region or a clear switchover at the concentration where the two phases have the same free energy. In terms of these features, the two binary systems, one with negative heat of mixing and one with positive heat of mixing, behave the same way. The external forcing action of mechanical alloying at low temperatures drives the system toward composition homogenization. There is no stable or metastable equilibrium, and the common tangent construction and lever rule are not applicable. What results is a novel two-phase coexistence which is defined by a region of overlapping solubility, rather than the normal solubility gap. That there can be two polymorphs at each composition even after the long ball-milling treatment represents a new type of steady-state two-phase coexistence that is completely different from the normal two-phase region dictated by thermodynamics

  4. [Cu2R2BrLi(thf)3], R = Si(SiMe3)3–a complex containing five-coordinate silicon in a three-centre two-electron bond (thf = tetrahydrofuran)

    OpenAIRE

    Heine, Andreas; Herbst-Irmer, Regine; Stalke, Dietmar

    1993-01-01

    The title compound is obtained from the reaction of (Me3Si)3SiLi(thf)3 with CuBr in n-hexane and structurally characterised by X-ray diffraction; in [Cu2R2BrLi(thf)3], R = Si(SiMe3)3 one silyl ligand is bridging a very short Cu–Cu bond, resulting in a three-centre two-electron bond, while the second is terminally bound to copper; the other copper atom is linked to a lithium atom via a Cu Br Li bridge.

  5. Geomaterials related to photovoltaics: a nanostructured Fe-bearing kuramite, Cu3SnS4

    Science.gov (United States)

    Di Benedetto, Francesco; Bencistà, Ilaria; D'Acapito, Francesco; Frizzera, Silvia; Caneschi, Andrea; Innocenti, Massimo; Lavacchi, Alessandro; Montegrossi, Giordano; Oberhauser, Werner; Romanelli, Maurizio; Dittrich, Herbert; Pardi, Luca A.; Tippelt, Gerold; Amthauer, Georg

    2016-09-01

    The successful synthesis of nanoparticles of Fe-bearing kuramite, (Cu,Fe)3SnS4, is reported in this study. Nanocrystalline powders were obtained through a mild, environmentally friendly and scalable solvothermal approach, in a single run. The sample was the object of a multidisciplinary investigation, including X-ray diffraction and absorption, scanning electron microscopy and microanalysis, electron paramagnetic resonance, diffuse reflectance and Mössbauer spectroscopy as well as SQUID magnetometry. The nanoparticles consist of pure Fe-bearing kuramite, exhibiting tetragonal structure. The valence state of the metal cations was assessed to be Cu+, Sn4+ and Fe3+. The material presents a band gap value of 1.6 eV, which is fully compatible with solar cell applications. The uptake of Fe by nanokuramite opens a compositional field where the physical properties can be tuned. We thus foster the application of Fe-bearing nanokuramite for photovoltaics and energy storage purposes.

  6. Preparation of nanometer FeCuP alloy and its application in decomposition of PH3

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800 ℃ to 400-500 ℃. The decomposition rate of phosphine achieved 100%.

  7. Atomic-partial vibrational density of states of i-AlCuFe quasicrystals

    CERN Document Server

    Parshin, P P; Brand, R A; Dianoux, A J; Calvayrac, Y

    2002-01-01

    We present new results on the separation of the atomic-partial vibrational density of states for the ternary quasicrystal i-Al sub 6 sub 2 Cu sub 2 sub 5 sub . sub 5 Fe sub 1 sub 2 sub . sub 5. The decomposition into three atomic-partial functions, Al-, Cu- and Fe-g(E), has been performed self-consistently with the calculation of the multi-phonon contributions. The results show the surprising result that both Cu- and Fe-g(E) are strongly peaked. The low-energy regions of Al- and Cu-g(E) show strong deviations from Debye behaviour due to the presence of non-propagating low-energy vibrational states. (orig.)

  8. The lattice structure of nanocrystalline Fe-Cu-Si-B alloys

    Science.gov (United States)

    Liu, X. D.; Lu, K.; Ding, B. Z.; Hu, Z. Q.; Zhu, J.; Jiang, J.

    1994-02-01

    Nanocrystalline Fe-Cu-Si-B alloys with different grain sizes were synthesized by crystallization of an amorphous alloy. Two nanophases, α-Fe(Se) and Fe 2B, were noticed in all samples. XRD results reveal that the lattice constant of the α-Fe(Si) phase increases; the a-axis is elongated and the c-axis is shortened in the Fe 2B phase upon reducing the grain size. Based on the thermodynamic analysis, the changes in the lattice parameters were attributed to the solution of vacancies in the above two phases. Owing to the lattice distortion of the α-Fe(Si) and Fe 2B phases, the crystallite with small size is found to exhibit a disordered character to some extent, which is manifested by large values of the half linewidth (HLW) and isomer shift (IS) of various Fe configurations in the Mössbauer parameters.

  9. Changes in the real structure and magnetoresistance of Co90Fe10/Cu and Co90Fe10/Cu85Ag10Au5 multilayers after annealing

    International Nuclear Information System (INIS)

    Annealing of the (1.1 nm Co90Fe10/2.2 nm Cu)x20 and (1.1 nm Co90Fe10/2.2 nm Cu85Ag10Au5)x20 multilayers at 235 deg. C improved their magnetoresistance as compared to the virgin samples. Annealing at higher temperatures resulted in degradation of the magnetoresistance effect. This observation raised the motivation of a detailed structural study using small-angle X-ray scattering, wide-angle X-ray diffraction, electron diffraction and transmission electron microscopy with the aim to link the structural changes in the system to the changes in the magnetoresistance. The structure studies have shown that the maximum of the magnetoresistance observed after annealing at 235 deg. C is related to the separation of Co90Fe10 and Cu, which are partly intermixed at interfaces after the deposition process. The decay of the GMR effect at higher annealing temperatures is caused by an increase of the interface roughness, which led in the Co90Fe10/Cu multilayers to occurrence of non-continuous interfaces and to short-circuiting of magnetic layers. In the Cu85Ag10Au5 multilayers, the combination of small-angle X-ray scattering and wide-angle X-ray diffraction has shown that Cu85Ag10Au5 did not form an alloy with the nominal composition: Only a part of Au and Ag was dissolved in the copper structure; the remainder of Ag and Au formed precipitates

  10. The microstructure of liquid immiscible Fe-Cu-based in situ formed amorphous/crystalline composite

    International Nuclear Information System (INIS)

    In the microstructures of slowly and rapidly cooled liquid of the immiscible alloy Fe30Cu32Ni10Si13Sn4B9Y2 two distinct regions were observed following arc melting and slow cooling, confirming that liquid/liquid phase separation had occurred. Rapid cooling from a temperature within the liquid immiscibility gap, melt spinning, resulted in an amorphous/crystalline composite, formed from the previously melted Fe- and Cu-rich regions, respectively. Transmission electron microscopic studies of this melt-spun ribbon revealed the glassy nature of the Fe-rich matrix, as well as of the Fe-rich spheres formed within the previously existing Cu-rich liquid

  11. Structure and magnetic properties of Fe63.5Co10Cu1Nb3Si13.5B9 alloy

    OpenAIRE

    D. Szewieczek; T. Raszka

    2006-01-01

    Purpose: In this paper results of experience of influence a structure (amorphous, amorphous after structuralrelaxation and nanocrystal) and influence a corrosion medium, which was 1 M solution NaCl, on magneticproperties (initial magnetic permeability μp, relative magnetic permeability μw, coercive field Hc, remanenceBr and saturation magnetisation Bs) on Fe63.5Co10Cu1Nb3Si13.5B9 alloy have been presented.Design/methodology/approach: The material was obtained by the method of rapid cooling fr...

  12. Facile synthesis and excellent recyclable photocatalytic activity of pine cone-like Fe3O4@Cu2O/Cu porous nanocomposites.

    Science.gov (United States)

    Wang, Haisheng; Hu, Yongan; Jiang, Yang; Qiu, Lingguang; Wu, Haibin; Guo, Ben; Shen, Yuhua; Wang, Yang; Zhu, Ling; Xie, Anjian

    2013-04-14

    L-Cys-modified Fe3O4 was first prepared by a one-step partially-reduced method under mild conditions. Then, novel pine cone-like Fe3O4@Cu2O/Cu nanocomposites (NCs) with photomagnetic difunction were successfully synthesized via a one-pot solvothermal method on Fe3O4 without any additional linker or reducer. The average diameter of the as-synthesized products was about 4 μm, and the products were orderly assembled into many sheets with an average thickness of ~100 nm, possessing a porous structure. A possible formation mechanism of Fe3O4@Cu2O/Cu NCs involving interfacial recognization of ions, nucleation, aggregation, in situ transformation from Cu2O to Cu and Ostwald ripening process is proposed. The pine cone-like porous composites show excellent photocatalytic activity such that MO degradation efficiency is about 96% at an irradiation time of 20 min under visible light. Also, the composites present higher stability than Fe3O4@Cu2O and do not exhibit any significant loss after five recycles for the photodegradation of MO. The above results demonstrate that Cu could improve the photocatalytic activity of NCs and also inhibit the photocorrosion behavior of NCs. These novel Fe3O4@Cu2O/Cu composite materials are ideal candidates in water treatment and environmental cleaning as well as in magnetic applications, etc. PMID:23380894

  13. Oxidation of two ternary Fe-Cu-5Al alloys in 1×105 Pa pure oxygen at 700 ℃

    Institute of Scientific and Technical Information of China (English)

    XIANG Jun-huai; NIU Yan; WU Wei-tao; LIU Guo-dong

    2006-01-01

    The oxidation of two two-phase ternary Fe-Cu-Al alloys containing about 5% Al(mole fraction),one Fe-rich and one Cu-rich,were studied at 700 ℃ in 1×105 Pa pure oxygen. The Fe-rich alloy (Fe-15Cu-5Al) shows two quasi-parabolic stages,with a large increase of the parabolic rate constant after about 4 h. The presence of 5% Al does not change greatly the oxidation rate of Fe-15Cu-5Al with respect to a binary Fe-Cu alloy of similar composition,which was quite different from the situation of the same alloys oxidized at 800 ℃. Oxidation of Fe-15Cu-5Al at 700 ℃ produced an outer layer of iron oxides and an inner layer containing a mixture of copper metal,iron and aluminium oxide. On the contrary,the Cu-rich Fe-85Cu-5Al alloy presents a rather irregular kinetic behavior,with formation of an inner continuous alumina thin layer and a rather irregular outer layer. The outer layer with a rather irregular thickness was mainly composed of a matrix of copper oxides plus some aluminium and iron oxides presenting in the deep part of the layer at certain locations. As a result of the formation of a protective alumina layer,the presence of 5% Al greatly reduced the oxidation rate of Fe-85Cu-5Al with respect to a binary Fe-Cu alloy of similar composition,which was also quite different from the situation of the same alloys oxidized at 800 ℃. Moreover,the oxidation rate at 700 ℃ of the Fe-85Cu-5Al alloy was much lower than that of Fe-15Cu-5Al alloy due to the same reason..

  14. Synthesis, Structure and Photoluminescent Properties of the 2D Coordination Polymers Based on Cu2Br2 Unit with Flexible Thioether%基于柔性硫醚与Cu2Br2单元二维配位聚合物的合成、结构和荧光性质

    Institute of Scientific and Technical Information of China (English)

    李冬青; 时文娟

    2009-01-01

    A complex [Cu2Br2(L)2]2 (1) (L=bis (2-pyrimidinylthio)methane) has been synthesized and structurally characterized. Complex 1 contains dinuclear Cu2Br2 units, which are linked by ditopic L to form a 2D layer structure with a 36-membered macrometallocycle. The adjacent layers are further connected through interpyrimidyl rings C-H strong green solid-state photoluminescence, due to metal-to-ligand charge-transfer (MLCT) at room temperature. CCDC: 711434.

  15. First principles calculation of stable structure and adhesive strength of plated Ni/Fe(100) or Cu/Fe(100) interfaces

    Institute of Scientific and Technical Information of China (English)

    Ryota NAKANISHI; Koji SUEOKA; Seiji SHIBA; Makoto HINO; Koji MURAKAMI; Ken MURAOKA

    2009-01-01

    A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed. Ni or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) substrate. Other calculations showed that the interfaces of Ni (5 atomic layers)/Fe(100) (5 layers) or Cu (5 atomic layers)/Fe(100) (5 layers) had square lattices. The orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100), Ni[011]//Fe[010], and Similar results were obtained for Cu/Fe(100) interfaces. This structure was supported by TEM analysis of plated Ni layer on Fe(100) surfaces. The adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) interface. The experimental results of Hull cell iron plated with Ni or Cu supported the results of the calculation. These results indicate that the first principles calculation, which deals with the ideal interface at the atomic scale, has the potential to evaluate the adhesion strength of metallic material interfaces.

  16. Electron spin resonance insight into broadband absorption of the Cu3Bi(SeO32O2Br metamagnet

    Directory of Open Access Journals (Sweden)

    A. Zorko

    2016-05-01

    Full Text Available Metamagnets, which exhibit a transition from a low-magnetization to a high-magnetization state induced by the applied magnetic field, have recently been highlighted as promising materials for controllable broadband absorption. Here we show results of a multifrequency electron spin resonance (ESR investigation of the Cu3Bi(SeO32O2Br planar metamagnet on the kagome lattice. Its mixed antiferromagnetic/ferromagnetic phase is stabilized in a finite range of applied fields around 0.8 T at low temperatures and is characterized by enhanced microwave absorption. The absorption signal is non-resonant and its boundaries correspond to two critical fields that determine the mixed phase. With decreasing temperature these increase like the sublattice magnetization of the antiferromagnetic phase and show no frequency dependence between 100 and 480 GHz. On the contrary, we find that the critical fields depend on the magnetic-field sweeping direction. In particular, the higher critical field, which corresponds to the transition from the mixed to the ferromagnetic phase, shows a pronounced hysteresis effect, while such a hysteresis is absent for the lower critical field. The observed hysteresis is enhanced at lower temperatures, which suggests that thermal fluctuations play an important role in destabilizing the highly absorbing mixed phase.

  17. Quantum Monte Carlo simulation of antiferromagnetic spin ladder (C5H12N)2CuBr4

    Science.gov (United States)

    Freitas, Augusto S.

    2016-07-01

    In this paper I present a Quantum Monte Carlo (QMC) study of the magnetic properties of an antiferromagnetic spin ladder (C5H12N)2CuBr4. This compound is the prototype of the Heisenberg model for a two leg spin ladder in the presence of an external magnetic field. The susceptibility phase diagram has a rounded peak in the vicinity of T=7.4 K, obeys Troyer's law for low temperatures, and Curie's law for high temperatures. I also study the susceptibility diagram in low temperatures and I found the spin gap Δ=9.26 K, in good concordance with the experimental value, 9.5 K. In high field, I present a diagram of magnetization as a function of temperature. In the vicinity of a critical field, Hci, the magnetization scales with T1/2 and this result was found also in the QMC simulation. In all the results, there is a very good concordance with the experimental data. I also show in this paper that the spin gap is null and the susceptibility is proportional to T for low temperatures when relatively high values of the ladders' coupling is taken in account.

  18. Recrystallization Behavior of CoCrCuFeNi High-Entropy Alloy

    Science.gov (United States)

    Park, Nokeun; Watanabe, Ikuto; Terada, Daisuke; Yokoyama, Yoshihiko; Liaw, Peter K.; Tsuji, Nobuhiro

    2015-04-01

    We investigated the recrystallization behavior of a cold-rolled CoCrCuFeNi high-entropy alloy (HEA). Two different face-centered cubic phases having different chemical compositions and lattice constants in the as-cast specimen have different chemical compositions: One phase was the Cu-lean matrix and the other was the Cu-rich second phase. The second phase remained even after a heat treatment at 1373 K (1100 °C) and Cu enriched more in the Cu-rich second phase. The calculated mixing enthalpies of both Cu-lean and Cu-rich phases in the as-cast and heat-treated specimens explained that Cu partitioning during the heat treatment decreased the mixing enthalpy in both phases. In the specimens 90 pct cold rolled and annealed at 923 K, 973 K, and 1073 K (650 °C, 700 °C, and 800 °C), recrystallization proceeded with increasing the annealing temperature, and ultrafine recrystallized grains with grain sizes around 1 μm could be obtained. The microhardness tended to decrease with increasing the fraction recrystallized, but it was found that the microhardness values of partially recrystallized specimens were much higher than those expected by a simple rule of mixture between the initial and cold-rolled specimens. The reason for the higher hardness was discussed based on the ultrafine grain size, sluggish diffusion expected in HEAs, and two-phase structure in the CoCrCuFeNi alloy.

  19. Assessment of Post-eutectic Reactions in Multicomponent Al-Si Foundry Alloys Containing Cu, Mg, and Fe

    Science.gov (United States)

    Javidani, Mousa; Larouche, Daniel; Grant Chen, X.

    2015-07-01

    Post-eutectic reactions occurring in Al-Si hypoeutectic alloys containing different proportions of Cu, Mg, and Fe were thoroughly investigated in the current study. As-cast microstructures were initially studied by optical and electron microscopy to investigate the microconstituents of each alloy. Differential scanning calorimetry (DSC) was then used to examine the phase transformations occurring during the heating and cooling processes. Thermodynamic calculations were carried out to assess the phase formation under equilibrium and in nonequilibrium conditions. The Q-Al5Cu2Mg8Si6 phase was predicted to precipitate from the liquid phase, either at the same temperature or earlier than the θ-Al2Cu phase depending on the Cu content of the alloy. The AlCuFe-intermetallic, which was hardly observed in the as-cast microstructure, significantly increased after the solution heat treatment in the alloys containing high Cu and Fe contents following a solid-state transformation of the β-Al5FeSi phase. After the solution heat treatment, the AlCuFe-intermetallics were mostly identified with the stoichiometry of the Al7Cu2Fe phase. Thermodynamic calculations and microstructure analysis helped in determining the DSC peak corresponding to the melting temperature of the N-Al7Cu2Fe phase. The effect of Cu content on the formation temperature of π-Al8Mg3FeSi6 is also discussed.

  20. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  1. Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

    Science.gov (United States)

    Kurtan, U; Amir, Md; Baykal, A; Sözeri, H; Toprak, M S

    2016-03-01

    Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water. PMID:27455668

  2. TPR and TPD studies of effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts

    Indian Academy of Sciences (India)

    Olusola O James; Biswajit Chowdhury; Sudip Maity

    2013-05-01

    Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe-Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3→Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe-Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe-Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

  3. Rietveld refinement of the mixed boracite Fe(1.59)Zn(1.41)B(7)O(13)Br.

    Science.gov (United States)

    Ulloa-Godínez, Sandra; Rosales, Ivonne; Bucio, Lauro; Farías, Mario H; Campa-Molina, Jorge

    2009-01-01

    The structural characterization of the new iron-zinc hepta-borate bromide with composition Fe(1.59)Zn(1.41)B(7)O(13)Br, prepared by chemical transport is reported. A rigid-body model with constrained generalized coordinates was defined in order to hold the positions of the B atoms at reasonable inter-atomic distances that typically would reach unacceptable values because of the weak scattering power of boron. There are three independent sites for the B atoms of which two are tetra-hedrally coordinated. The bond-valence sum around the third B atom, located on a threefold rotation axis, was calculated considering two cases of coordination of boron with oxygens: trigonal-planar and tetrahedral. The contribution of the fourth O atom to the bond-valence sum was found to be only 0.06 v.u., indicating the presence of a very weak bond in the right position to have a distorted tetra-hedral coordination in favour of the trigonal-planar coordination for the third B atom. X-ray fluorescence (XRF) was used to determinate the Fe/Zn ratio. PMID:21578040

  4. Spark plasma sintering of a nanocrystalline Al-Cu-Mg-Fe-Ni-Sc alloy

    Science.gov (United States)

    Zúñiga, Alejandro; Ajdelsztajn, Leonardo; Lavernia, Enrique J.

    2006-04-01

    The microstructure and aging behavior of a nanocrystalline Al-Cu-Mg-Fe-Ni-Sc alloy was studied. The nanocrystalline powders were produced by milling at liquid nitrogen temperature and then consolidated using spark plasma sintering (SPS). The microstructure after SPS consisted of a bimodal aluminum grain structure (coarse-grained and fine-grained regions), along with Al9FeNi and Al2CuMg particles dispersed throughout. The microstructure observed in the as-consolidated sample is rationalized on the basis of high current densities that are generated during sintering. Solution treatment and aging of the SPS Al-Cu-Mg-Fe-Ni-Sc sample resulted in softening instead of hardening. This observation can be explained by the reduced amount of Cu, Mg, and Si in solid solution available to form S' Al2CuMg due to the precipitation of Al7FeCu2 and Si-rich particles, and by the fact that rodlike S' Al2CuMg particles could only precipitate out in the coarse-grained regions, greatly decreasing their influence on the hardness. This lack of precipitation in the fine-grained region is argued to represent a new physical observation and is rationalized on the basis of physical and thermodynamic effects. The nanocrystalline SPS Al-Cu-Mg-Fe-Ni-Sc sample was also extremely thermally stable, retaining a fine-grained structure even after solution treatment at 530°C for 5 h. The observed thermal stability is rationalized on the basis of solute drag and Zener pinning caused by the impurities introduced during the cryomilling process.

  5. Distribution of Ca, Fe, Cu and Zn in primary colorectal cancer and secondary colorectal liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ebraheem, A. [Department of Radiography, City Community and Health Sciences, City University, London, EC1V 0HB (United Kingdom); Mersov, A. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main St. West. Hamilton, Ontario, L8S 4L8 (Canada); Gurusamy, K. [HPB and Liver Transplant Surgery, Royal Free and University College School of Medicine, UCL and Royal Free NHS trust, London (United Kingdom); Farquharson, M.J., E-mail: farquhm@mcmaster.c [Department of Medical Physics and Applied Radiation Sciences, McMaster University, 1280 Main St. West. Hamilton, Ontario, L8S 4L8 (Canada)

    2010-07-21

    A microbeam synchrotron X-ray fluorescence ({mu}SRXRF) technique has been used to determine the localization and the relative concentrations of Zn, Cu, Fe and Ca in primary colorectal cancer and secondary colorectal liver metastases. 24 colon and 23 liver samples were examined, all of which were formalin fixed tissues arranged as microarrays of 1.0 mm diameter and 10 {mu}m thickness. The distribution of these metals was compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cells. Histological details were provided for each sample which enable concentrations of all elements in different tissue types to be compared. In the case of liver, significant differences have been found for all elements when comparing tumour, normal, necrotic, fibrotic, and blood vessel tissues (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have also been found to be significantly different among tumour, necrotic, fibrotic, and mucin tissues in the colon samples (Kruskal Wallis Test, P<0.0001). The concentrations of all elements have been compared between primary colorectal samples and colorectal liver metastases. Concentration of Zn, Cu, Fe and Ca are higher in all types of liver tissues compared to those in the colon tissues. Comparing liver tumour and colon tumour samples, significant differences have been found for all elements (Mann Whitney, P<0.0001). For necrotic tissues, significant increase has been found for Zn, Ca, Cu and Fe (Mann Whitney, P<0.0001 for Fe and Zn, 0.014 for Ca, and 0.001 for Cu). The liver fibrotic levels of Zn, Ca, Cu and Fe were higher than the fibrotic colon areas (independent T test, P=0.007 for Zn and Mann Whitney test P<0.0001 for Cu, Fe and Ca). For the blood vessel tissue, the analysis revealed that the difference was only significant for Fe (P=0.009) from independent T test.

  6. Post-irradiation annealing behavior of neutron-irradiated FeCu, FeMnNi and FeMnNiCu model alloys investigated by means of small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, F. [Helmholtz-Zentrum Dresden-Rossendorf, POB 510119, 01314 Dresden (Germany); Ulbricht, A., E-mail: a.ulbricht@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, POB 510119, 01314 Dresden (Germany); Lindner, P. [Institut Laue-Langevin Grenoble, BP 156, 38042 Grenoble Cedex 9 (France); Keiderling, U. [Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Malerba, L. [SCK-CEN Mol, Boeretang 200, 2400 Mol (Belgium)

    2014-11-15

    Neutron irradiation of reactor pressure vessel steels gives rise to the formation of thermodynamically stable and unstable nano-features. The present work is focused on the stability of Cu-, Mn- and Ni-containing solute clusters in model alloys exposed to post-irradiation annealing. Fe0.1Cu, Fe1.2Mn0.7Ni and Fe1.2Mn0.7Ni0.1Cu (wt%) model alloys irradiated up to neutron exposures of 0.1 and 0.19 dpa (displacements per atom) were annealed at stepwise increasing temperatures in the range from 300 °C (i.e. near irradiation temperature) to 500 °C and characterized by means of small-angle neutron scattering (SANS). We have found characteristic differences in the annealing behavior of the alloys. In particular, there is a non-trivial (synergistic–antagonistic) interplay of Mn/Ni and Cu.

  7. Microstructure and mechanical properties of Fe-Cu-Sn sintered alloy%Fe-Cu-Sn烧结体的显微组织与力学性能

    Institute of Scientific and Technical Information of China (English)

    何娟; 王日初; 彭超群; 郑虎春

    2011-01-01

    分别采用水雾化Fe-30%Cu合金粉末和单质Sn、Fe、Cu元素粉末为原料制备Fe-Cu-Sn合金,研究原料粉末和Sn含量(质量分数)对Fe-Cu-Sn烧结体致密度、冲击韧性、硬度和抗弯强度的影响.结果表明:与采用元素混合粉末相比,采用合金化程度较高的Fe-30%Cu(质量分数,下同)合金粉末为原料能大幅提高850℃烧结的Fe-Cu-5%Sn合金的致密度和力学性能,其致密度由82.8%提高到94.3%,硬度、冲击韧性和抗弯强度分别提高52%、84%和109%:当Sn的质量分数w(Sn)为3%-15%时,随着Sn质量分数增加,合金的硬度增大,冲击韧性和抗弯强度先增加后减小,其中w(Sn)为5%时,其抗弯强度和冲击韧性都较高,分别为977 MPa和11.6 J/cm2.当烧结体为"双重结构"组织时,其力学性能显著提高.

  8. Interfacial tension studies between Fe-Cu-Ni sulfide and halo-norilsk basalt slag system

    Institute of Scientific and Technical Information of China (English)

    SU; Shangguo

    2005-01-01

    The interfacial tension of the matte/halo-Norilsk basalt slag systems of FeS-Cu2S-Ni3S2 and FeO-FeS were investigated using the sessile drop technique. The results indicate that interfacial tension decreases with increasing copper and nickel contents in the matte of FeS-Cu2S-Ni3S2 system while it increases with increasing oxygen content in the matte of FeO-FeS system. It is inferred from these results that two conditions are critical for the formation of giant Cu-Ni sulfide deposits. One is that mafic-ultramafic parent magma of sulfide deposits should be rich in copper and nickel where due to the low interfacial tension, it is difficult to form sulfide droplet in the early stage of magma evolution. In other words, sulfide liquid conglomeration occurs more difficultly. The other condition is that the magma emplacement should be shallow; and a lot of faults occur in the magma emplacement field. Since oxygen content is high in the environment, interfacial tension is high, which helps sulfide liquid conglomeration and consequently Cu-Ni sulfide deposits form.

  9. The effect of magnetic layer thickness on magnetic properties of Fe/Cu multilayer nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Almasi-Kashi, M., E-mail: almac@kashanu.ac.ir [Department of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan (Iran, Islamic Republic of); Ramazani, A. [Department of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan (Iran, Islamic Republic of); Kheyri, F.; Jafari-Khamse, E. [Department of Physics, University of Kashan, Kashan (Iran, Islamic Republic of)

    2014-04-01

    Fe/Cu multilayer nanowires were ac-pulse electrodeposited into the anodic aluminum oxide templates prepared by a two-step mild anodization technique. Transmission electron microscopy images showed the distinct layers with a relatively high contrast. A highly pure layer (∼99%) was achieved by tuning the proper ions ratio and optimizing the off-time between pulses of each layer in the single electrodeposition bath. Fe/Cu multilayer nanowires with 38 nm diameter were obtained. The effect of reducing the Fe layer thickness on the magnetic properties of Fe/Cu multilayer nanowires was investigated. It was seen that reducing the Fe layer thickness, thereby variation of rode- to disc-like multilayer nanowires, caused to rotate the magnetic easy axis from parallel to perpendicular to the wires axis. - Highlights: • Changing off-time and ac voltage enables control in segments of multilayer nanowire. • As TEM images show thickness of alternative layers was adjustable by pulse numbers. • A new technique was introduced to grow compositionally-modulated multilayer nanowire. • Two distinct Fe and Cu diffraction peaks indicates formation of two distinct phases. • Identical coercivity in IP and OOP configurations ascribed vanishing shape anisotropy.

  10. Fabrication of Cu2O/γ-FeOOH heterojunction solar cells using electrodeposition

    Science.gov (United States)

    Vequizo, Junie Jhon M.; Ichimura, Masaya

    2014-04-01

    Cu2O/γ-FeOOH heterojunction solar cells were fabricated using galvanostatic-potentiostatic electrodeposition methods. The γ-FeOOH films showed n-type conductivity with a band gap of 2.2 eV. The electrodeposited Cu2O/γ-FeOOH heterojunction exhibited photovoltaic characteristics with a short-circuit current density of 0.95 mA/cm2 and open-circuit voltage of 0.11 V. Using core-level spectroscopy, it was demonstrated that the Cu2O/FeOOH heterostructure exhibited a type II junction with a valence band offset of 0.8 eV. The conduction band minimum of Cu2O was predicted to be higher than that of γ-FeOOH by 0.7 eV. This finding indicates that the γ-FeOOH material can be regarded as a suitable hetero-partner of other p-type absorbers.

  11. Preparation and characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu

    OpenAIRE

    Corredor, Edna C.

    2012-01-01

    El objetivo del trabajo realizado en esta tesis titulada: Preparation and magnetic characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu es establecer relaciones entre las propiedades magnéticas de sistemas nanoestructurados y sus dimensiones físicas o factores estructurales que aparecen al reducirse la dimensión espacial a dos, en el caso de películas delgadas, y a una en el caso de elementos patronados. Los sistemas objeto de estudio se caracterizan por se...

  12. Preparation and characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu

    OpenAIRE

    Corredor Vega, Edna Consuelo; Ciria Remacha, Miguel Ángel; Arnaudas Pontaque, José Ignacio

    2013-01-01

    El objetivo del trabajo realizado en esta tesis titulada: Preparation and magnetic characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu es establecer relaciones entre las propiedades magnéticas de sistemas nanoestructurados y sus dimensiones físicas o factores estructurales que aparecen al reducirse la dimensión espacial a dos, en el caso de películas delgadas, y a una en el caso de elementos patronados. Los sistemas objeto de estudio se caracterizan por se...

  13. Magnetic ordering of Fe atoms in the YBa2(Cu/0. 95/Fe/0. 05/)3O(7. 01) superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Liubutin, I.S.; Terziev, V.G.; Morozov, O.N. (Institut Kristallografii, Moscow (USSR))

    1990-11-01

    Moessbauer spectroscopy detected the magnetic ordering of Fe atoms in YBa2(Cu/0.95/Fe/0.05/)3O(y) in both the superconducting and the nonsuperconducting states. It is shown that, in the superconducting sample, the superconductivity coexists with magnetic ordering of the Fe atoms in Cu1 nodes. In the nonsuperconducting sample, the Fe atoms in the Cu1 nodes have a magnetic-ordering point (20 K) which is reduced by 10 K upon transition to the superconducting state. 15 refs.

  14. 快淬态纳米晶Fe-Cu-Ta-Si-B软磁金属薄带的制备%Preparation of As-quenched Nanocrystalline Fe-Cu-Ta-Si-B Soft Magnetic Ribbons

    Institute of Scientific and Technical Information of China (English)

    胡季帆; 李波; 秦宏伟

    2009-01-01

    Fe-Cu-Ta-Si-B纳米晶金属薄带可以通过快淬技术直接制备,而无需退火过程.对比Fe-Cu-Ta-Si-B快淬纳米晶薄带,发现相同Cu含量下,a-Fe(Si)更易在Fe-Cu-Nb-Si-B快淬态薄带中析出.在快淬态Fe-Cu-Ta-Si-B金属薄带中,适当高的Cu含量有利于α-Fe(Si)的成核;但过高的Cu含量反而弱化了纳米晶化,这是由于团簇效应粗化了Cu颗粒的尺寸,却减少了a-Fe(Si)的有效成核位置.

  15. Facile synthesis of Fe-incorporated CuO nanoarrays with enhanced electrochemical performance for lithium ion full batteries

    Energy Technology Data Exchange (ETDEWEB)

    Heng, Bojun [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Department of Applied Physics, Wuhan University of Science and Technology, Wuhan, 430065 (China); Qing, Chen; Wang, Hai; Sun, Daming; Wang, Bixiao [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China)

    2015-11-15

    CuO nanoarrays (CNAs) and Fe-incorporated CuO nanoarrays (FCNAs) were fabricated by hydrothermal method. Addition of Fe salt to the reaction mixture allowed the introduction of iron oxide onto the CNAs surface, which was characterized by XPS and HRTEM. Introducing Fe ion into reaction precursor significantly affected not only the morphologies of as-prepared products but also their electrochemical performance as anode for lithium ion full battery. The FCNAs electrodes showed higher specific capacity and better capacity retention at different current densities than that of CNAs. - Highlights: • Fe-incorporated CuO nanoarrays were fabricated by hydrothermal method. • Fe salt in reaction mixture leads to iron oxides forming on the surface of CuO. • Fe-incorporating improves the lithium ion battery performance of CuO anodes.

  16. Precipitation behavior of B2-like particles in Fe-Cu binary alloy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The precipitation behavior in Fe-Cu binary alloy was investigated under transmission electron microscope (TEM) during aging at 650℃ for the time range of to 300 h. In addition to the zones with higher copper content and -Cu were observed, a metastable phase with B2-like structure was found in the early stage of the precipitation process, which is quite different from the equilibrium copper phase shown inthe Fe-Cu binary phase diagram and has perfect coherent relationship to the -Fe matrix. The appearance of B2-like structure is very important concerning the mechanism of aging strengthening effect and mechanical properties of corresponding engineering steels and alloys containing copper.

  17. In Vitro Evaluation of Cu, Fe, and Zn Bioaccessibility in the Presence of Babassu Mesocarp.

    Science.gov (United States)

    Fioroto, Alexandre Minami; Nascimento, Angerson Nogueria; Oliveira, Pedro Vitoriano

    2015-07-22

    In vitro gastrointestinal digestion of babassu mesocarp in the absence and presence of milk and lignin was performed to evaluate the bioaccessibility of Cu, Fe, and Zn. Extractions using NaOH solutions (pH 7 and 12) were carried out to evaluate the interactions of Cu(II), Fe(III), and Zn(II) with the extracted compounds and with the washed mesocarp. Studies using reference solutions showed a decrease in the free concentration of the elements in the presence of mesocarp. Phytate, a component present in the mesocarp, can be the main compound responsible for the elements' interactions with mesocarp. Lignin increases the elements' soluble fractions; however, the elements' concentrations in the dialyzed fractions, representing the bioaccessible portion, were very low. On the other hand, Cu, Fe, and Zn bioaccessibility in milk was not influenced by the mesocarp. PMID:26134249

  18. Synthesis of higher alcohols over highly dispersed Cu-Fe based catalysts derived from layered double hydroxides.

    Science.gov (United States)

    Han, Xinyou; Fang, Kegong; Zhou, Juan; Zhao, Lu; Sun, Yuhan

    2016-05-15

    Highly dispersed Cu-Fe based catalysts with Fe/Cu molar ratios ranging from 0.2 to 1 were prepared via thermal decomposition of layered double hydroxides (LDHs) precursors and tested for higher alcohol synthesis (HAS) via CO hydrogenation. The catalysts were characterized using different techniques such as XRD, TEM, XPS, and H2-TPR. It was demonstrated that the Cu and Fe ions were highly dispersed in the brucite-like layers of the LDHs. With increased Fe/Cu atomic ratio, the tetrahedrally coordinated Cu ion content, Cu reduction temperatures, and the spacing of layers initially increase until the Fe/Cu ratio reaches 0.5 and then decrease. In addition to the catalytic evaluation for CO hydrogenation and catalyst characterization, the relationships between the physical-chemical properties of the catalysts and their catalytic performances were also investigated. It was also found that the alcohols/hydrocarbons ratios correlate linearly with the tetrahedrally coordinated Cu ion content. Moreover, higher reduction temperatures of Cu species as well as larger spacing between the layers in the catalyst are favorable for the synthesis of alcohols. The incorporation of a suitable amount of Fe is beneficial for the production of higher alcohols, with the best catalytic performance (alcohol selectivity of 20.77% and C2+ alcohol selectivity of 48.06%) obtained from a Fe/Cu atomic ratio of 0.5. PMID:26943001

  19. Development and characterization of the CU ground MAX-DOAS instrument: lowering RMS noise and first measurements of BrO, IO, and CHOCHO near Pensacola, FL

    OpenAIRE

    S. Coburn; Dix, B.; R. Sinreich; Volkamer, R.

    2011-01-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is directly proportional to the root mean square (RMS) of the residu...

  20. The CU ground MAX-DOAS instrument: characterization of RMS noise limitations and first measurements near Pensacola, FL of BrO, IO, and CHOCHO

    OpenAIRE

    S. Coburn; Dix, B.; R. Sinreich; Volkamer, R.

    2011-01-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer (O4) in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is proportional to the root mean square (RMS) of the residual spectrum th...

  1. Surface segregation and surface tension in liquid Fe-Cu alloys

    International Nuclear Information System (INIS)

    A simple statistical mechanics model has been used to study the temperature dependence of the surface properties of Fe-Cu liquid alloys. The calculated values for the composition dependence of surface segregation indicates that Cu atoms segregate to the surface and, in addition, that the surface tension in Fe-Cu alloys decreases with increasing copper content. Furthermore, our formalism is able to predict the temperature dependence of the surface properties for the liquid alloy based only on knowledge of the results at the melting point. This illustrates that the model used provides a simple recipe to extract information in the undercooled region about the dependence of surface properties in liquid binary alloys. In addition, close to the decomposition temperature, the surface concentration of Cu increases sharply in the undercooled region. (orig.)

  2. The anomaly Cu doping effects on LiFeAs superconductors.

    Science.gov (United States)

    Xing, L Y; Miao, H; Wang, X C; Ma, J; Liu, Q Q; Deng, Z; Ding, H; Jin, C Q

    2014-10-29

    The Cu substitution effect on the superconductivity of LiFeAs has been studied in comparison with Co/Ni substitution. It is found that the shrinking rate of the lattice parameter c for Cu substitution is much smaller than that of Co/Ni substitution. This is in conjugation with the observation of ARPES that shows almost the same electron and hole Fermi surfaces (FSs) size for undoped and Cu substituted LiFeAs sample, except for a very small hole band sinking below Fermi level with doping. This indicates that there is little doping effect at Fermi surface by Cu substitution, in sharp contrast to the more effective carrier doping effect by Ni or Co. PMID:25299428

  3. Relation between Charpy impact properties and magnetism in thermally aged Fe-Cu model alloys

    International Nuclear Information System (INIS)

    This study demonstrates the possibility of applying magnetic methods to pressure vessel surveillance for irradiation embrittlement at nuclear power plants. Charpy impact test and magnetic hesteresis measurement were preformed on thermally aged Fe-1.0wt%Cu model alloys with and without pre-deformation. DBTT increased with increasing aging time. However, magnetic hysteresis parameters showed nonmonotonical changes. The phenomena are discussed in terms of Cu precipitation behavior and dislocation structure. (author)

  4. Environmental impact and potential utilization of historical Cu-Fe-Co slags.

    Science.gov (United States)

    Veselská, Veronika; Majzlan, Juraj

    2016-04-01

    Historical slags from the past Fe and Cu-Co production were investigated in order to evaluate either their potential for utilization or their long-term environmental risk for unsupervised old smelting areas. Here, we studied ferrous slags produced during the recovery of Fe from siderite-Cu ores in Slovakia and two different types of non-ferrous slags produced during the recovery of Cu and Co from Kupferschiefer ores in Germany. The glassy character, rare occurrence of primary silicate phases, and the lack of secondary phases in Cu slags indicate their stability for a prolonged period of time. Electron microprobe analytical work showed that the metals and metalloids (Cu, Co, Fe, Zn, Pb, As) are largely encased in droplets of matte and metal alloys and remain protected by the glassy matrix with its low weathering rate. Fe and Co slags are composed of high-temperature silicates such as wollastonite, cristobalite, as well as olivine, feldspar, quartz, leucite, pyroxene, and pyroxenoids. The presence of secondary phases attests to a certain degree metal release owing to weathering. Assuming minimal contents of metals in slags after a treatment with dilute H2SO4, slags could be used as pozzolanas for addition to cement. PMID:26681328

  5. Distribution of Cu, Fe, Mn, and Zn in Two Mangroves of Southern Brazil

    Directory of Open Access Journals (Sweden)

    Ana Paula Lang Martins Madi

    2015-12-01

    Full Text Available ABSTRACT This study assessed the relation between Cu, Fe, Mn, and Zn in the soils of the mangroves of Antonina and Guaratuba, on the coastline of the State of Paraná, and in the leaf tissues of A. shauerianaR. mangle, and L. racemosa through the analysis of correlation levels between these two compartments. Leaf samples were collected for ten individuals of each species in a 1000 m2 area delimited in each mangrove. Soil samples from 0-10 cm depth were taken from under the crown projection area of the selected trees to be submitted to chemical analysis. In the soils, metallic micronutrients presented the following order: Fe > Mn > Zn > Cu. In the leaves, concentrations were species dependent. InA. shaueriana and R. mangle, the profile was Mn > Fe > Zn > Cu, while in L. racemosa, the sequence was: Fe > Mn > Zn > Cu. Correlation analyses revealed only four significant correlations for Mn, Zn, and Cu in the soil and plant compartments. These results suggested that significant correlations depended on abiotic factors, inhibition between the elements, and immobilization and/or adsorptions of these metals by the soil.

  6. Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

    Indian Academy of Sciences (India)

    U Turgut

    2004-11-01

    Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a 241Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (K) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

  7. Mogućnost uklanjanja olova iz industrijske Cu-Pb-Fe legure injektiranjem argonom

    OpenAIRE

    B. Oleksiak

    2009-01-01

    Mogućnost uklanjanja olova iz industrijske CU-Pb-Fe legure injektiranjem argonom. Članak daje rezultate istraživanja uklanjanja olova iz industrijske Cu-PB-Fe legure primjenom injektiranja argonom. Opiti su provedeni na pogonskoj leguri u Tvornici bakra "Glogow II". Kao temeljna oprema rabljena je pećna cijev, koja omogućava zagrijavanje uzorka iznad temperature 1773 K. Sva istraživanja su provedena na temperaturama 1473 K, 1523 K, 1573 K i strujom plina 5,55×10-6, 6,94×10-6, 8,33×10-6, 9,72×...

  8. Modeling and analysis of soybean (Glycine max. L Cu/Zn, Mn and Fe superoxide dismutases

    Directory of Open Access Journals (Sweden)

    V. Ramana Gopavajhula

    2013-01-01

    Full Text Available Superoxide dismutase (SOD, EC 1.15.1.1 is an important metal-containing antioxidant enzyme that provides the first line of defense against toxic superoxide radicals by catalyzing their dismutation to oxygen and hydrogen peroxide. SOD is classified into four metalloprotein isoforms, namely, Cu/Zn SOD, Mn SOD, Ni SOD and Fe SOD. The structural models of soybean SOD isoforms have not yet been solved. In this study, we describe structural models for soybean Cu/Zn SOD, Mn SOD and Fe SOD and provide insights into the molecular function of this metal-binding enzyme in improving tolerance to oxidative stress in plants.

  9. Cu(2+) and Fe(2+) mediated photodegradation studies of soil-incorporated chlorpyrifos.

    Science.gov (United States)

    Rafique, Nazia; Tariq, Saadia R; Ahad, Karam; Taj, Touqeer

    2016-03-01

    The influences of Cu(2+) and Fe(2+) on the photodegradation of soil-incorporated chlorpyrifos were investigated in the present study. The soil samples spiked with chlorpyrifos and selected metal ions were irradiated with UV light for different intervals of time and analyzed by HPLC. The unsterile and sterile control soil samples amended with pesticides and selected metals were incubated in the dark at 25 °C for the same time intervals. The results of the study evidenced that photodegradation of chlorpyrifos followed the first-order kinetics. The dissipation t0.5 of chlorpyrifos was found to decrease from 41 to 20 days under UV irradiation. The rate of chlorpyrifos photodegradation was increased in the presence of both metals, i.e., Cu(2+) and Fe(2+). Thus, initially observed t0.5 of 19.8 days was decreased to 4.39 days in the case of Cu(+2) and 19.25 days for Fe(+2). Copper was found to increase the rate of photodegradation by 4.5 orders of magnitude while the microbial degradation of chlorpyrifos was increased only twofold. The microbial degradation of chlorpyrifos was only negligibly affected by Fe(2+) amendment. The studied trace metals also affected the abiotic degradation of the pesticide in the order Cu(2+) > Fe(2+). PMID:26507736

  10. Crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4 from X-ray powder diffraction

    Indian Academy of Sciences (India)

    G E Delgado; A J Mora; P Grima-Gallardo; M Muñoz; S Durán; M Quintero; J M Briceño

    2015-08-01

    The crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4, belonging to the system I–II2–III–VI4, were characterized using X-ray powder diffraction data. Both compounds crystallize in the tetragonal space group I42m (No. 121), = 2, with unit cell parameters = 5.609(1) Å, = 10.963(2) Å for CuFe2AlSe4 and = 5.6165(3) Å, = 11.075(1) Å for CuFe2GaSe4. These compounds are isostructural with CuFe2InSe4, and have a normal adamantane stannite structure.

  11. Neutron diffraction study of magnetic ordering in PrCu2Si2, PrCu2Ge2, PrFe2Ge2 and NdFe2Ge2

    International Nuclear Information System (INIS)

    A neutron diffraction study of polycrystalline PrCu2Si2, PrCu2Ge2, PrFe2Ge2 and NdFe2Ge2 intermetallics carried out at liquid helium temperature shows the presence of a collinear antiferromagnetic order below Tsub(N). Magnetic moment, parallel to the c-axis is localized on RE ions only. The magnetic structure of these compounds consists of ferromagnetic layers perpendicular to the c-axis coupled antiferromagnetically with sequence +-+- for PrCu2Si2 and PrCu2Ge2 and +--+ for PrFe2Ge2 and NdFe2Ge2. The RE moments amount close to the free ion values for Fe containing compounds but are smaller in those containing Cu suggesting a fairly strong influence of crystal field. (author)

  12. Fine scale remobilisation of Fe, Mn, Co, Ni, Cu and Cd in contaminated marine sediment

    DEFF Research Database (Denmark)

    Tankere-Muller, Sophie; Zhang, Hao; Davison, William;

    2007-01-01

    to less than 0.3 μM. With both DET and DGT measurements, there were sharply defined maxima of Cu and Cd within 2 mm of the sediment water interface, consistent with their release from organic material as it is oxidised. There was a Co maximum about 5–8 mm lower than the Cu and Cd maxima, apparently...... that the localised mobilisation of metals was associated with recent diagenetic processes, rather than the depositional history. There were substantial fluxes of Cu and Cd to the overlying water. Even though there were steep gradients of Fe, Mn, Ni and Co within 1 cm of the sediment–water interface...

  13. Delafossite CuFeO2 thin films electrochemically grown from a DMSO based solution

    International Nuclear Information System (INIS)

    Highlights: • A detailed electrochemical study about the electrodeposition of CuFeO2 from DMSO solution is presented. • The use of a precise quantity of chloride ion as complexing agent is decisive in order to obtain stoichiometric compounds (Cu:Fe ratio 1:1). • As-grown compounds were amorphous. Thus, a thermal treatment was required in order to obtain crystalline CuFeO2 with delafossite structure. • The formation of CuFeO2 was confirmed by XRD and XPS analyses. • Through optical measurements, four absorption in different spectrum regions were characterized: A IR absorption (Eg(IR) = 1.64 eV), two visible absorptions (Egdir(vis) = 2.35 eV, and Egind(vis) = 2.03 eV) and an UV absorption (Egind(UV) = 3.37 eV). - Abstract: This study shows the results obtained in the direct electrodeposition of CuFeO2 thin films from a DMSO based solution. First, a detailed electrochemical study was carried out in order to determinate the best condition for the CuFeO2 electrodeposition. The films were obtained potentiostatically from a 0.01 M CuCl2 + 0.005 M Fe(ClO4)3 + 0.1 M LiClO4 solution in the presence of molecular oxygen at 50 °C onto FTO/glass substrates. In all cases, the time of electrodeposition was 1000 s. The grown films presented a yellow-reddish color and exhibit an homogeneous aspect. Analyses of composition carried out through EDS, shown that a stoichiometric composition (atomic relation Cu:Fe = 1:1) is obtained at a potential of –0.6 V. However, as-grown films analyzed through XRD experiences did not evidence the presence of CuFeO2 compound presumably because it is amorphous. An annealing treatment at 650° C for 30 minutes in an argon atmosphere was necessary to transform the solid phase of the as grown films in crystalline CuFeO2. Furthermore, the presence of CuFeO2 has been confirmed through XPS analyses. UV-vis analyzes shown a ladder-like appearance due to the presence of several absorption edges from the IR to the UV spectrum region. The most

  14. A GREENER SYNTHESIS OF CORE (FE, CU)-SHELL (AU, PT, PD AND AG) NANOCRYSTALS USING AQUEOUS VITAMIN C

    Science.gov (United States)

    A greener method to fabricate the novel core (Fe and Cu)-shell (noble metals) metal nanocrystals using aqueous ascorbic acid (vitamin C) is described. Transition metal salts such as Cu and Fe were reduced using ascorbic acid, a benign naturally available antioxidant, and then add...

  15. Solution-based synthesis and characterization of Cu{sub 2}FeSnS{sub 4} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Li Liang; Liu Xiuyong; Huang Jian [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Cao Meng, E-mail: caomeng@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Chen Shiyou [Key Laboratory of Polar Materials and Devices, East China Normal University, Shanghai 200241 (China); Shen Yue; Wang Linjun [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer We synthesis Cu{sub 2}FeSnS{sub 4} nanocrystals with hot injection method. Black-Right-Pointing-Pointer We characterize the structure and morphology of Cu{sub 2}FeSnS{sub 4} nanocrystals. Black-Right-Pointing-Pointer The band gap of Cu{sub 2}FeSnS{sub 4} nanocrystals is determined from the absorption spectra. - Abstract: Cu{sub 2}FeSnS{sub 4} nanocrystals were cost-effectively synthesized by thermal reactions of metal salts and sulfur in a hot oleylamine solution. Stannite structured Cu{sub 2}FeSnS{sub 4} nanocrystals with diameters of about 15-25 nm were obtained, analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The morphology of the continuous Cu{sub 2}FeSnS{sub 4} thin films was characterized by scanning electron microscopy (SEM) and the average compositions of the nanocrystals were determined by energy dispersive X-ray analysis (EDX). High-resolution X-ray photoemission spectroscopy (XPS) analysis of the four constituent elements indicated Cu (I), Fe (II), Sn (IV) and sulfide ions. The band gap of as-synthesised Cu{sub 2}FeSnS{sub 4} nanocrystals is about 1.33 eV determined by the UV-vis-NIR absorption spectra measurement, which indicates its possible solar cell applications.

  16. Improvement of Thermal Stability of Nd-Tb-Fe-Co-B Sintered Magnets by Additions of Pr, Ho, Al, and Cu

    Directory of Open Access Journals (Sweden)

    A. A. Lukin

    2012-01-01

    Full Text Available The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡. The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,2515(Fe0,71Co0,29bal ⋅ Al0,9Cu0,1B8,5 (at. % after optimal thermal treatment {1175 K (3,6–7,2 ks with slow (12–16 ks cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.

  17. Adsorption of arsenate on Cu/Mg/Fe/La layered double hydroxide from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yanwei [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Zhu, Zhiliang, E-mail: zzl@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Qiu, Yanling [Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized. Black-Right-Pointing-Pointer The average pore size of the materials with about 16 nm indicated that the mesoporous structures existed in the Cu/Mg/Fe/La-LDHs. Black-Right-Pointing-Pointer The adsorption capacity of As(V) increased with the increment of La{sup 3+} content in the LDH. Black-Right-Pointing-Pointer The maximum adsorption capacity of the synthesized Cu/Mg/Fe/La-LDH for arsenate was 43.5 mg/g. - Abstract: A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized and used for the removal of arsenate from aqueous solutions. The purpose of incorporation of La{sup 3+} into LDHs was tried to enhance the uptake efficiency of arsenate and broaden the application field of LDHs functional materials. Effects of various physico-chemical factors such as solution pH, adsorbent dosage, contact time and initial arsenate concentrations on the adsorption of arsenate onto Cu/Mg/Fe/La-LDH were investigated. Results showed that the removal efficiency of arsenate increased with the increment of the lanthanum content in Cu/Mg/Fe/La-LDH adsorbents, and the optimized lanthanum content was 20% of the total trivalent metals composition (Fe{sup 3+} and La{sup 3+}). The adsorption isotherms can be well described by Langmuir equation, and the adsorption kinetics of arsenate followed the pseudo-second-order kinetic model. Coexistent ions such as HPO{sub 4}{sup 2-}, CO{sub 3}{sup 2-}, SO{sub 4}{sup 2-}, Cl{sup -} and NO{sub 3}{sup -} exhibited obvious competition with arsenate for the adsorption on Cu/Mg/Fe/La-LDH. The solution pH significantly affected the removal efficiency, which was closely related to the change of arsenate species distribution under different pH conditions. The predominant adsorption mechanism can be mainly attributed to the processes including ion exchange and layer ligand exchange.

  18. Comparative investigation of CuFe2O4 nano and microstructures for structural, morphological, optical and magnetic properties

    Science.gov (United States)

    Raja, G.; Gopinath, S.; Raj, R. Azhagu; Shukla, Arun K.; Alhoshan, Mansour S.; Sivakumar, K.

    2016-09-01

    CuFe2O4 nanocrystals were synthesized by the sol-gel method (SGM) and microwave method (MM) by using sucrose as a fuel. The structural, morphological, optical and magnetic properties of the products were determined and characterized in detail by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). The XRD results confirmed the formation of cubic phase CuFe2O4. The formation of CuFe2O4 nano and microstructures were confirmed by HR-SEM. Photoluminescence emissions were determined by PL spectra, respectively. The relatively high saturation magnetization (78.22 emu/g) of CuFe2O4-MM shows that it is ferromagnetic and low saturation magnetization (35.98 emu/g) of CuFe2O4O-SGM confirms the super paramagnetic behavior.

  19. Effects of Si/Al Ratio on Cu/SSZ-13 NH3-SCR Catalysts: Implications for the active Cu species and the Roles of Brønsted Acidity

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Washton, Nancy M.; Wang, Yilin; Kollar, Marton; Szanyi, Janos; Peden, Charles HF

    2015-09-03

    Cu/SSZ-13 catalysts with three Si/Al ratios of 6, 12 and 35 were synthesized with Cu incorporation via solution ion exchange. The implications of varying Si/Al ratios on the nature of the multiple Cu species that can be present in the SSZ-13 zeolite are a major focus of this work, as highlighted by the results of a variety of catalyst characterization and reaction kinetics measurements. Specifically, catalysts were characterized with surface area/pore volume measurements, temperature programmed reduction by H2 (H2-TPR), NH3 temperature programmed desorption (NH3-TPD), and DRIFTS and solid-state nuclear magnetic resonance (NMR) spectroscopies. Catalytic properties were examined using NO oxidation, ammonia oxidation, and standard ammonia selective catalytic reduction (NH3-SCR) reactions on selected catalysts under differential conditions. Besides indicating possible variably active multiple Cu species for these reactions, the measurements are also used to untangle some of the complexities caused by the interplay between redox of Cu ion centers and Brønsted acidity. All three reactions appear to follow a redox reaction mechanism, yet the roles of Brønsted acidity are quite different. For NO oxidation, increasing Si/Al ratio lowers Cu redox barriers, thus enhancing reaction rates. Brønsted acidity appears to play essentially no role for this reaction. For standard NH3-SCR, residual Brønsted acidity plays a significant beneficial role at both low- and high-temperature regimes. For NH3 oxidation, no clear trend is observed suggesting both Cu ion center redox and Brønsted acidity play important and perhaps competing roles. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of

  20. Comparison study of Cu-Fe-Ti and Co-Fe-Ti oxide catalysts for selective catalytic reduction of NO with NH3 at low temperature.

    Science.gov (United States)

    Zhu, Lin; Zhong, Zhaoping; Yang, Han; Wang, Chunhua

    2016-09-15

    In this paper, a series of Cu-Fe-Ti and Co-Fe-Ti oxide catalysts were prepared by sol gel method. Cu-Fe-Ti and Co-Fe-Ti oxide catalysts showed the moderate catalytic activity for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The catalysts with the molar ratio as 4:1:10 (M:Fe:Ti) were selected as the representatives for comparison of reaction properties and H2O resistance, which were denoted as Cu-Fe/TiO2 and Co-Fe/TiO2 respectively. The characterization results manifested Co-Fe/TiO2 owned more adsorption capacity of the reactants and Cu-Fe/TiO2 had better redox ability. The in situ DRIFTS experiments indicated that adsorbed NH3 species and nitrate species both exhibited reaction activity for Co-Fe/TiO2, while nitric oxide was only be reduced by adsorbed NH3 species through Eley-Rideal mechanism for Cu-Fe/TiO2 at 150°C. Co-Fe/TiO2 exhibited the better resistance to H2O and its temperature window shifted towards the higher temperature in presence of 10vol% H2O, while the SCR activity of Cu-Fe/TiO2 was inhibited significantly in the whole temperature range investigated. The suppression of adsorption and activation for NH3 and NOx might be the reasons for the reversible inactivation, which was confirmed by the inhibitation of catalytic activities for separation NH3 and NO oxidation under the wet condition. We speculated that different thermal stability of adsorbed species and redox capacity of catalysts leaded to the different SCR behavior in absence and presence of H2O. PMID:27280535

  1. Effects of ultrasonic field in pulse electrodeposition of NiFe film on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, R. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Yow, H.K. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia)], E-mail: hkyow@mmu.edu.my; Ong, B.H. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Manickam, R. [Electronics Faculty, Tyndale Education Group Pte Ltd., 188942 (Singapore); Saaminathan, V. [School of Material Science and Engineering, Nanyang Technological University, 639798 (Singapore); Tan, K.B. [Department of Chemistry, Universiti Putra Malaysia, Serdang, 43400 (Malaysia)

    2009-07-29

    NiFe film was pulse electrodeposited on conductive Cu substrate under galvanostatic mode in the presence of an ultrasonic field. The NiFe film electrodeposited was subjected to structural and surface analyses by X-ray diffraction, energy dispersive X-ray spectroscopy, surface profiling and scanning electron microscopy, respectively. The results show that the ultrasonic field has significantly improved the surface roughness, reduced the spherical grain size in the range from 490-575 nm to 90-150 nm, and increased the Ni content from 76.08% to 79.74% in the NiFe film electrodeposited.

  2. Mechanical alloying in Fe2O3-MO (M: Zn, Ni, Cu, Mg) systems

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gerward, Leif; Mørup, Steen

    1999-01-01

    Mechanical alloying processes in four Fe2O3MO (M: Zn, Ni, Cu, Mg) systems by high-energy ball milling from simple oxide powder mixtures in both open and closed tungsten carbide containers have been investigated by x-ray powder diffraction and Mossbauer spectroscopy. Mechanisms for the formation o...

  3. The structure and magnetic properties of a powder FeCuNbSiB material

    International Nuclear Information System (INIS)

    We investigated the influence of milling on the structure and magnetic properties of Fe73.5Cu1Nb3Si13.5B9 alloy as a function of milling time. We found that with an increase of milling time the size of the powder decreases and both the coercivity and the volume fraction of the crystalline phase increase

  4. Fine-particle magnetism in nanocrystalline Fe-Cu-Nb-Si-B at elevated temperatures

    International Nuclear Information System (INIS)

    Magnetic interactions between the nanocrystalline particles in FeCuNbSiB are studied above the Curie temperature of the intergranular amorphous phase. It is shown that with increasing volume fraction of nanocrystalline particles, the interparticle interaction increasingly suppresses superparamagnetic fluctuations and the transition to superferromagnetic behavior is observed. ((orig.))

  5. Cu substitution effects on the local magnetic properties of Ba(Fe(1-x)Cu(x))(2)As(2): a site-selective (75)As and (63)Cu NMR study.

    Science.gov (United States)

    Takeda, Hikaru; Imai, Takashi; Tachibana, Makoto; Gaudet, Jonathan; Gaulin, Bruce D; Saparov, Bayrammurad I; Sefat, Athena S

    2014-09-12

    We take advantage of the site-selective nature of the ^{75}As and ^{63}Cu NMR techniques to probe the Cu substitution effects on the local magnetic properties of the FeAs planes in Ba(Fe_{1-x}Cu_{x})_{2}As_{2}. We show that the suppression of antiferromagnetic Fe spin fluctuations induced by Cu substitution is weaker than a naive expectation based on a simple rigid band picture, in which each Cu atom would donate three electrons to the FeAs planes. Comparison between ^{63}Cu and ^{75}As NMR data indicates that spin fluctuations are suppressed at the Cu and their neighboring Fe sites in the tetragonal phase, suggesting the strongly local nature of the Cu substitution effects. We attribute the absence of a large superconducting dome in the phase diagram of Ba(Fe_{1-x}Cu_{x})_{2}As_{2} to the emergence of a nearly magnetically ordered FeAs plane under the presence of orthorhombic distortion.

  6. Synthesis and Crystal Structure of a Novel Mixed Nido-like and Half-open Cubane-like Cluster [(n-Bu)4N]3[MoS4Cu5Br6

    Institute of Scientific and Technical Information of China (English)

    LIU,Quai(刘泉); XU,Qing-Feng(徐庆锋); ZHANG,Yong(张勇); CHEN,Jin-Xiang(陈金香); ZHOU,Zhi-Feng(周志峰); LANG,Jian-Ping(郎建平)

    2002-01-01

    Reaction of (NH4)2MoS4 with [Cu(MeCN)4] (BF4) and (nBu)4NBr in CH2Cl2 afforded a new hexanuclear cluster [ ( nBu)4N]3[MoS4Cu5Br6] (1). 1 crystallizes in the monoclinic system, space group P21/c, with lattice parameters a =1.17383(4) nm, b = 2.40136(4) nm, c = 2.64112(5) nm,β =94.2020(5)°, V=7.4247(5) nm3andZ=4. The structure of the [MoS4Cu5Br6]3- trianion of 1 is composed of one nidolike [MoS3Cu3] core and one half-open cubane-like [MoS3Cu3Br] core, which are interconnected by sharing the of 0.2622(6)-0.2692(5) nm.

  7. Comparative study on the reactivity of Fe/Cu bimetallic particles and zero valent iron (ZVI) under different conditions of N2, air or without aeration.

    Science.gov (United States)

    Xiong, Zhaokun; Lai, Bo; Yang, Ping; Zhou, Yuexi; Wang, Juling; Fang, Shuping

    2015-10-30

    In order to further compare the degradation capacity of Fe(0) and Fe/Cu bimetallic system under different aeration conditions, the mineralization of PNP under different aeration conditions has been investigated thoroughly. The results show that the removal of PNP by Fe(0) or Fe/Cu system followed the pseudo-first-order reaction kinetics. Under the optimal conditions, the COD removal efficiencies obtained through Fe(0) or Fe/Cu system under different aeration conditions followed the trend that Fe/Cu (air)>Fe/Cu (N2: 0-30 min, air: 30-120 min)>control-Fe (air)>Fe/Cu (without aeration)>Fe/Cu (N2)>control-Fe (N2). It revealed that dissolved oxygen (DO) could improve the mineralization of PNP, and Cu could enhance the reactivity of Fe(0). In addition, the degradation of PNP was further analyzed by using UV-vis, FTIR and GC/MS, and the results suggest that Fe/Cu bimetallic system with air aeration could completely break the benzene ring and NO2 structure of PNP and could generate the nontoxic and biodegradable intermediate products. Meanwhile, most of these intermediate products were further mineralized into CO2 and H2O, which brought about a high COD removal efficiency (83.8%). Therefore, Fe/Cu bimetallic system with air aeration would be a promising process for toxic refractory industry wastewater.

  8. Multifractal analysis of the strength of Fe-Cu paragenetic relationships in eastern Tianshan, China

    Science.gov (United States)

    Zhao, Jie; Wang, Wenlei; Cheng, Qiuming

    2016-04-01

    Paragenetic association of elements is a natural and important geological phenomenon reflecting the geochemical behavior of elements during various geo-processes. Because of intrinsic characteristics, different elements of paragenetic association may also be generated. As a result, the respective material sources could be shifted from the original locations, and the strength of paragenetic association of elements could be declined. Therefore, study of paragenetic association of elements can help in locating material source, characterizing migration form, and indicating precipitation conditions. Resulted from complicated and cascade geo-processes, the strength of paragenetic relationship between elements presents variations in space. To examine influences of the strength of paragenetic association of elements on polymetallic mineralization, the current research proposes a data processing procedure that includes non-linear regression and multifractal analysis of the resulting regression coefficients. This procedure is currently tested in the eastern Tianshan mineral district, China, and encouraging results are being derived. In this research, geographically weighted regression (GWR), which is a non-linear statistical method, is used to examine the relationship between Fe and Cu concentrations in eastern Tianshan mineral district, China. This local regression method allows calculation of coefficients for Fe and Cu concentrations at every individual location. Therefore, the variation of the strength of Fe-Cu paragenetic association across the study area can be derived. Furthermore, a multifractal method, spectrum-area (S-A) analysis is applied to the regression coefficient map in order to delineate locations strong associated with Fe-Cu mineralization. Anomalies indicating very strong paragenetic association are separated from background. In addition, noise indicating locations with strong paragenetic relationships but that are not suitable for Fe-Cu mineralization are

  9. Solderability of Electrodeposited Fe-Ni Alloys with Eutectic SnAgCu Solder

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Solderabilities of electrodeposited Fe-Ni alloys with SnAgCu solder were examined by wetting balance measurements and compared to those of pure Ni and pure Fe platings. Excellent solderability was found on the Ni-52Fe plating as both the wetting force and kinetics approached or exceeded those on the pure Ni. However,upon further increase in Fe content to 75 at. pct, the solderability of the alloy was severely degraded even though it was still better than that of the pure Feplating. X-ray photoelectron spectroscopy showed that such a strong dependence of solderability on Fe content is related to the much thinner, incomplete oxide coverage of Ni-rich plating surface.

  10. Fabrication and fibre matrix interface characteristics of Cu/C(Fe composite

    Directory of Open Access Journals (Sweden)

    Li Y.

    2009-01-01

    Full Text Available Cu/C composites were successfully fabricated by three step electro-deposition. The effects of hot pressure temperature and alloy element Fe on the interface characteristic of Cu/C composite were investigated. The results showed that the hot pressure temperature and interface characteristic have a great effect on mechanical properties of the composite. The tensile strength and hardness increase firstly and then decrease with the increasing of hot pressure temperature, and a tensile rupture appears when the hot pressure temperature is 650, 700 and 900oC. The addition of alloy element Fe not only improves the tensile strength and the lateral shear strength of the Cu/C composite, but also changes the interface bond type from the physical bond type to the chemical bond type.

  11. Effect of Fe and Cu on Electrochemical Characteristics of Low-Co AB5 Type Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhu Xilin; Zhou Yu; Chong Fayao; Li Xiaochun; Pan Weilin

    2004-01-01

    In order to further reduce the cost of AB5 type rare earth-based hydrogen storage alloy, a low-Co AB5 type hydrogen storage alloy were by substituting Co with Cu and Fe.The characteristics of these alloys have been investigated by means of XRD, PCT, and measurement of electrochemical capacity and cycle life.The test results show that the effect of these two kinds of substituting elements on discharge capacity is CuFe, and the cycle life is on the contrary.Both of them have no distinct influence on activity speed, but activity speed increases with the decrease of Co.By the order way, the high discharge rate characteristics rise with the addition of Cu and decreasing of Co.

  12. EFFECT OF COPPER ON PASSIVITY AND CORROSION BEHAVIOR OF FE-XC-5CU ALLOY

    Directory of Open Access Journals (Sweden)

    M. Ferhat

    2014-06-01

    Full Text Available The correlation between corrosion behavior rate of annealed Fe-xC-5Cu alloys and their microstructure and phase composition is presented. The metallurgical analyses, including, X-Ray diffraction (XRD, the scanning electron microscopy (SEM with energy dispersive analysis (EDX, and induction hardening characterization are conducted to study the Fe-C-Cu alloys. Corrosion parameters in H2SO4 1N solution have been established by carrying out electrochemical studies such as potentiodynamic (Tafel polarization and linear polarization, LP and electrochemical impedance spectroscopy (EIS. The coupled effect copper/microstructure is discussed. Alloying Cu showed a beneficial effect on hypoeutectoid steel and harmful effect on hypereutectoid steel. The improved corrosion resistance is related to cementite morphology and by a copper dissolution/re-deposition process.

  13. EFFECT OF COPPER ON PASSIVITY AND CORROSION BEHAVIOR OF FE-XC-5CU ALLOY

    Directory of Open Access Journals (Sweden)

    M. Ferhat

    2015-07-01

    Full Text Available The correlation between corrosion behavior rate of annealed Fe-xC-5Cu alloys and their microstructure and phase composition is presented. The metallurgical analyses, including, X-Ray diffraction (XRD, the scanning electron microscopy (SEM with energy dispersive analysis (EDX, and induction hardening characterization are conducted to study the Fe-C-Cu alloys. Corrosion parameters in H2SO4 1N solution have been established by carrying out electrochemical studies such as potentiodynamic (Tafel polarization and linear polarization, LP and electrochemical impedance spectroscopy (EIS. The coupled effect copper/microstructure is discussed. Alloying Cu showed a beneficial effect on hypoeutectoid steel and harmful effect on hypereutectoid steel. The improved corrosion resistance is related to cementite morphology and by a copper dissolution/re-deposition process.

  14. 'Venus trapped, Mars transits': Cu and Fe redox chemistry, cellular topography and in situ ligand binding in terrestrial isopod hepatopancreas.

    Science.gov (United States)

    Kille, P; Morgan, A J; Powell, K; Mosselmans, J F W; Hart, D; Gunning, P; Hayes, A; Scarborough, D; McDonald, I; Charnock, J M

    2016-03-01

    Woodlice efficiently sequester copper (Cu) in 'cuprosomes' within hepatopancreatic 'S' cells. Binuclear 'B' cells in the hepatopancreas form iron (Fe) deposits; these cells apparently undergo an apocrine secretory diurnal cycle linked to nocturnal feeding. Synchrotron-based µ-focus X-ray spectroscopy undertaken on thin sections was used to characterize the ligands binding Cu and Fe in S and B cells of Oniscus asellus (Isopoda). Main findings were: (i) morphometry confirmed a diurnal B-cell apocrine cycle; (ii) X-ray fluorescence (XRF) mapping indicated that Cu was co-distributed with sulfur (mainly in S cells), and Fe was co-distributed with phosphate (mainly in B cells); (iii) XRF mapping revealed an intimate morphological relationship between the basal regions of adjacent S and B cells; (iv) molecular modelling and Fourier transform analyses indicated that Cu in the reduced Cu(+) state is mainly coordinated to thiol-rich ligands (Cu-S bond length 2.3 Å) in both cell types, while Fe in the oxidized Fe(3+) state is predominantly oxygen coordinated (estimated Fe-O bond length of approx. 2 Å), with an outer shell of Fe scatterers at approximately 3.05 Å; and (v) no significant differences occur in Cu or Fe speciation at key nodes in the apocrine cycle. Findings imply that S and B cells form integrated unit-pairs; a functional role for secretions from these cellular units in the digestion of recalcitrant dietary components is hypothesized. PMID:26935951

  15. Characterizing As, Cu, Fe and U solubilization by natural waters

    OpenAIRE

    Noubactep, C.; Schöner, A.; Schubert, M

    2008-01-01

    The effects of carbonate concentration and the presence of in-situ generated iron oxide and hydroxide phases (iron oxyhydroxides) on arsenic (As), copper (Cu), and uranium (U) release from natural rocks were investigated under oxic conditions and in the pH range from 6 to 9. For this purpose non-disturbed batch experiments were conducted with a constant amount of each contaminant bearing rock/mineral and different types of water (deionised, mineral, spring, and tap water). For comparison para...

  16. More Cu, more problems: Decreased CO2 conversion ability by Cu-doped La0.75Sr0.25FeO3 perovskite oxides

    Science.gov (United States)

    Daza, Yolanda A.; Maiti, Debtanu; Hare, Bryan J.; Bhethanabotla, Venkat R.; Kuhn, John N.

    2016-06-01

    The effect of Cu doping on the conversion of CO2 to CO was investigated on H2-reduced La0.75Sr0.25FeO3 perovskite oxides. Six La0.75Sr0.25Fe1 -YCuYO3 perovskites, labeled Cu100*Y (with Y = 0, 0.10, 0.25, 0.50, 0.75, and 1) were synthesized and characterized through X-ray diffraction (XRD), temperature-programmed oxygen vacancy formation, and temperature-programmed reduction (TPR). The incorporation of Cu facilitates the formation of oxygen vacancies at lower temperatures but also increased the instability of the perovskite. DFT simulations suggested that the Cu10 sample is favored to produce oxygen vacancies compared to Cu0 and Cu25 samples, which was consistent with experimental oxygen vacancy formation results. For the Cu0, Cu10, and Cu25 samples, temperature-programmed CO2 conversion (TPO-CO2) after isothermal H2-reduction at 450 °C and post-reduction XRD were performed to evaluate the ability of the materials to convert CO2 at low temperatures and to identify the crystalline phases active in the reaction. The peak conversion of CO2 to CO was achieved 30 °C lower on the Cu10 sample versus the Cu0, but less CO was produced, due to a decreased re-oxidation activity of the Cu-doped samples. CO production was inhibited in the Cu25 sample, likely due to a combined effect of poor CO2 dissociative chemisorption energies on metallic Cu and increased thermodynamic stability of the oxygen vacant perovskites. Control experiments (Cu deposited onto La0.75Sr0.25FeO3) indicated the stability of the copper-containing perovskite oxides phases was the primary limiting factor preventing CO formation from CO2.

  17. Anomalous grain growth in nanocrystalline Fe73.5Cu1Nb3Su13.5B9 alloys

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    1997-01-01

    The grain growth of the FeSi phase during the crystallization process of the amorphous Fe73.5Cu1Nb3Si13.5B9 alloy was studied using transmission electron microscopy and x-ray diffractometry. An anomalous grain growth behaviour of the FeSi phase in the samples annealed in temperature range from 74...

  18. Changes of microstructure and magnetic properties of Nd-Fe-B sintered magnets by doping Al-Cu

    Energy Technology Data Exchange (ETDEWEB)

    Ni Junjie [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); College of Materials Science and Engineering, Liaocheng University, Liaocheng 252000 (China); Ma Tianyu [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yan Mi, E-mail: mse_yanmi@zju.edu.cn [Department of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

    2011-11-15

    The microstructural and magnetic properties of Al{sub 100-x}Cu{sub x} (15at%{<=}x{<=}45 at%) doped Nd-Fe-B magnets were studied. The distribution and alloying effects of Cu or Al on the intergranular microstructure were investigated by thermodynamic analysis, differential scanning calorimetery and microscopy techniques. It was observed that when the Cu content of Al{sub 100x}Cu{sub x} exceeds to 25 at%, the (Pr, Nd)Cu and CuAl{sub 2} phases form in these magnets. The formation of (Pr, Nd)Cu phase depends on the negative formation enthalpy of (Pr, Nd)Cu and the exclusive distribution of Cu in the intergranular regions. The eutectic reaction between (Pr, Nd)Cu phase and (Pr, Nd) occurs at 480 deg. C, which forms the liquid phase that dissolves the (Pr, Nd){sub 2}Fe{sub 14}B surface irregularities and thus increases the quantities of (Pr, Nd)-rich phase at the grain boundaries. These changes benefit the grain boundary microstructure, especially the distribution of (Pr, Nd)-rich phase, which effectively improves the intrinsic coercivity {sub i}H{sub c} due to the decreases of exchange coupling between the (Pr, Nd){sub 2}Fe{sub 14}B grains. - Highlights: > Cu/Al effects on Nd-Fe-B structure depend on their distribution/alloying behaviors. > Cu exclusively distributes in grain boundaries different from Al and has negative mixing heat with Nd. > (Pr,Nd)Cu phase besides CuAl{sub 2} forms in grain boundaries with Cu content increase. > (Pr,Nd)Cu phases optimize microstructure and increase magnetic properties.

  19. Effect of small additions of Cu and Cr on crystallization of Fe80B9Si11 amorphous alloy

    International Nuclear Information System (INIS)

    By means of differential thermal and X-ray structure analyses, as well as, by measurement of microstrength one studied the effect of small additions of chromium and copper on the peculiarities of crystallization of Fe80B9Si11 amorphous alloy (Fe79Cr1B9Si11 and Fe79Cu1B9Si11). Chromium was determined to stabilize Fe3B nonequilibrium phase the formation of which resulted in eutectic type of crystallization at early stages while copper was determined to enable formation of α-Fe and Fe2B equilibrium phases and primary crystallization with precipitation of α-Fe primary crystals

  20. Thermodynamic analysis of binary Fe85B15 to quinary Fe85Si2B8P4Cu1 alloys for primary crystallizations of α-Fe in nanocrystalline soft magnetic alloys

    Science.gov (United States)

    Takeuchi, A.; Zhang, Y.; Takenaka, K.; Makino, A.

    2015-05-01

    Fe-based Fe85B15, Fe84B15Cu1, Fe82Si2B15Cu1, Fe85Si2B12Cu1, and Fe85Si2B8P4Cu1 (NANOMET®) alloys were experimental and computational analyzed to clarify the features of NANOMET that exhibits high saturation magnetic flux density (Bs) nearly 1.9 T and low core loss than conventional nanocrystalline soft magnetic alloys. The X-ray diffraction analysis for ribbon specimens produced experimentally by melt spinning from melts revealed that the samples were almost formed into an amorphous single phase. Then, the as-quenched samples were analyzed with differential scanning calorimeter (DSC) experimentally for exothermic enthalpies of the primary and secondary crystallizations (ΔHx1 and ΔHx2) and their crystallization temperatures (Tx1 and Tx2), respectively. The ratio ΔHx1/ΔHx2 measured by DSC experimentally tended to be extremely high for the Fe85Si2B8P4Cu1 alloy, and this tendency was reproduced by the analysis with commercial software, Thermo-Calc, with database for Fe-based alloys, TCFE7 for Gibbs free energy (G) assessments. The calculations exhibit that a volume fraction (Vf) of α-Fe tends to increase from 0.56 for the Fe85B15 to 0.75 for the Fe85Si2B8P4Cu1 alloy. The computational analysis of the alloys for G of α-Fe and amorphous phases (Gα-Fe and Gamor) shows that a relationship Gα-Fe ˜ Gamor holds for the Fe85Si2B12Cu1, whereas Gα-Fe Fe85Si2B8P4Cu1 alloy at Tx1 and that an extremely high Vf = 0.75 was achieved for the Fe85Si2B8P4Cu1 alloy by including 2.8 at. % Si and 4.5 at. % P into α-Fe. These computational results indicate that the Fe85Si2B8P4Cu1 alloy barely forms amorphous phase, which, in turn, leads to high Vf and resultant high Bs.

  1. Development and characterization of the CU ground MAX-DOAS instrument: lowering RMS noise and first measurements of BrO, IO, and CHOCHO near Pensacola, FL

    Directory of Open Access Journals (Sweden)

    S. Coburn

    2011-01-01

    Full Text Available We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS instrument to retrieve bromine oxide (BrO, iodine oxide (IO, formaldehyde (HCHO, glyoxal (CHOCHO, nitrogen dioxide (NO2 and the oxygen dimer O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is directly proportional to the root mean square (RMS of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS values of ~6 × 10-6 without apparent limitations other than photon shot noise. <br>> Laboratory tests revealed two factors that, in practice, limit the RMS: (1 detector non-linearity noise, RMSNLin, and (2 temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (~10−3 yet – unless actively controlled – is sufficiently large to create a RMSNLin limit of up to 1.4 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels/°C at 334 nm, and temperature variations of 0.1 °C can cause residual RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. <br>> The CU GMAX-DOAS was set up at a coastal site near Pensacola, FL, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL, with daytime average tropospheric vertical column densities, VCDs, of ~2 × 1013 molec cm−2, 8 × 1012 molec cm−2 and 4 × 1014 molec cm−2, respectively. HCHO and NO2 were also detected with typical MBL VCDs of 1

  2. The CU ground MAX-DOAS instrument: characterization of RMS noise limitations and first measurements near Pensacola, FL of BrO, IO, and CHOCHO

    Directory of Open Access Journals (Sweden)

    S. Coburn

    2011-11-01

    Full Text Available We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS instrument to retrieve bromine oxide (BrO, iodine oxide (IO, formaldehyde (HCHO, glyoxal (CHOCHO, nitrogen dioxide (NO2 and the oxygen dimer (O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is proportional to the root mean square (RMS of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS of ∼6 × 10−6 from solar stray light noise tests using high photon count spectra (compatible within a factor of two with photon shot noise. <br>> Laboratory tests revealed two critical instrument properties that, in practice, can limit the RMS: (1 detector non-linearity noise, RMSNLin, and (2 temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (∼10−2 yet – unless actively controlled – is sufficiently large to create RMSNLin of up to 2 × 10−4. The optical resolution is sensitive to temperature changes (0.03 detector pixels °C−1 at 334 nm, and temperature variations of 0.1°C can cause RMSFWHM of ~1 × 10−4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. With an integration time of 60 s the instrument can reach RMS noise of 3 × 10−5, and typical RMS in field measurements ranged from 6 × 10−5 to 1.4 × 10−4. <br>> The CU GMAX-DOAS was set up at a coastal site near Pensacola, Florida, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL, with daytime

  3. Study of Cu-doping effects on magnetic properties of Fe-doped ZnO by first principle calculations

    Indian Academy of Sciences (India)

    A El Amiri; H Lassri; M Abid; E K Hlil

    2014-06-01

    Using ab initio calculations on Zn0.975–Fe0.025CuO ( = 0, 0.01, 0.02, 0.05), we study the variations of magnetic moments vs Cu concentration. The electronic structure is calculated by using the Korringa–Kohn–Rostoker (KKR) method combined with coherent potential approximation (CPA). We show that the total magnetic moment and magnetic moment of Fe increase on increasing Cu content. From the density of state (DOS) analysis, we show that Cu-induced impurity bands can assure, by two mechanisms, the enhancement of Fe magnetic moment in Zn0.975–Fe0.025CuO.

  4. Solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO

    Directory of Open Access Journals (Sweden)

    Boyanov B.S.

    2005-01-01

    Full Text Available The solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO have been studied using X-ray diffraction analysis. The influence of the temperature on the ferrite formation process has been investigated in the range of 900-1200 oC and duration up to 360 min. It has been shown that a mixture of ferrites forms at 1000 oC and interaction of 240 min. The exchange reactions in the systems CuFe2O4-CaO and Cu0.5Zn0.5Fe2O4-CaO have been studied, too. It has been established that Ca2+ ions exchange Cu2+ and Zn2 partially and the solubility of copper and zinc in a 7 % sulfuric acid solution increases 10-15 times.

  5. Comparing XMCD and DFT with STM spin excitation spectroscopy for Fe and Co adatoms on Cu2N /Cu (100 )

    Science.gov (United States)

    Etzkorn, M.; Hirjibehedin, C. F.; Lehnert, A.; Ouazi, S.; Rusponi, S.; Stepanow, S.; Gambardella, P.; Tieg, C.; Thakur, P.; Lichtenstein, A. I.; Shick, A. B.; Loth, S.; Heinrich, A. J.; Brune, H.

    2015-11-01

    We report on the magnetic properties of Fe and Co adatoms on a Cu2N /Cu(100 ) -c (2 ×2 ) surface investigated by x-ray magnetic dichroism measurements and density functional theory (DFT) calculations including the local coulomb interaction. We compare these results with properties formerly deduced from STM spin excitation spectroscopy (SES) performed on the individual adatoms. In particular we focus on the values of the local magnetic moments determined by XMCD compared to the expectation values derived from the description of the SES data. The angular dependence of the projected magnetic moments along the magnetic field, as measured by XMCD, can be understood on the basis of the SES Hamiltonian. In agreement with DFT, the XMCD measurements show large orbital contributions to the total magnetic moment for both magnetic adatoms.

  6. Magnetic ordering of Fe atoms in oxygen-saturated and oxygen-reduced YBa sub 2 (Cu sub 1-x Fe sub x ) sub 3 O sub y

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, I.S.; Terziev, V.G.; Dmitrieva, T.V. (Inst. of Crystallography, Academy of Sciences, Moscow (Russia)); Balagurov, A.M. (Joint Inst. for Nuclear Research, Dubna (Russia)); Nasu, S. (Dept. of Material Physics, Osaka Univ. (Japan))

    1992-06-01

    The magnetic ordering of Fe atoms in the YBa{sub 2}(Cu{sub 1-x}Fe{sub x}){sub 3}O{sub y} system is studied in the superconducting (SC) and non-SC states by Moessbauer spectroscopy. In the SC samples a single magnetic ordering point T{sub m1} is observed for all Fe atoms: T{sub m1}=10 K and 16 K for x=0.05 and 0.10, respectively. In the non-SC state for x=0.05 the Cu(1) and Cu(2) sublattices are magnetically independent and two magnetic ordering points are found: T{sub m1}=20 K and T{sub m2}=405 K. For x=0.10 a strong magnetic coupling between the Cu(1) and Cu(2) sublattices leads to a single magnetic ordering temperature T{sub m2}=435 K. (orig.).

  7. Note: Resonance magnetoelectric interactions in laminate of FeCuNbSiB and multilayer piezoelectric stack for magnetic sensor

    Science.gov (United States)

    Li, Jianqiang; Lu, Caijiang; Xu, Changbao; Zhong, Ming

    2015-09-01

    This paper develops a simple miniature magnetoelectric (ME) laminate FeCuNbSiB/PZT-stack made up of magnetostrictive Fe73.5Cu1Nb3Si13.5B9 (FeCuNbSiB) foils and piezoelectric Pb(Zr, Ti)O3 (PZT) multilayer stack vibrator. Resonant ME interactions of FeCuNbSiB/PZT-stack with different layers of FeCuNbSiB foil (L) are investigated in detail. The experimental results show that the ME voltage coefficient reaches maximum value of 141.5 (V/cm Oe) for FeCuNbSiB/PZT-stack with L = 6. The AC-magnetic sensitivities can reach 524.29 mV/Oe and 1.8 mV/Oe under resonance 91.6 kHz and off-resonance 1 kHz, respectively. The FeCuNbSiB/PZT-stack can distinguish small dc-magnetic field of ˜9 nT. The results indicate that the proposed ME composites are very promising for the cheap room-temperature magnetic field sensing technology.

  8. Heat content of liquid Fe-Cu-Si alloys formed in the melting treatment process of domestic waste incineration residue

    International Nuclear Information System (INIS)

    Some new melting processes for the ash have been developed to solve the problems on increasing volume of ash generated from municipal waste incinerators. The metal phase formed in this melting process generally consists of Fe-Cu-Si-P-C containing a small amount of other heavy metals, but their phase equilibria and physico-chemical properties are unknown. The present work aimed at determining the thermochemical properties of liquid Fe-Cu-Si alloys, which establish the basic system in this melting process. The heat contents of liquid Fe, Fe-Cu and Fe-Cu-Si alloys have been directly measured with a drop calorimeter at mainly 2073 K in the present work. The observed heat content and the enthalpy of mixing of the alloys were assessed by a thermodynamic model. The input energy which should be supplied to melt the metal phase in the new melting treatment process was also discussed. (orig.)

  9. Chemistry and electronic properties of ferromagnetic metal-organic semiconductor interfaces: Fe on CuPc

    Energy Technology Data Exchange (ETDEWEB)

    Aristov, V.Yu. [IFW Dresden, 01069 Dresden (Germany); Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Molodtsova, O.V.; Knupfer, M. [IFW Dresden, 01069 Dresden (Germany); Ossipyan, Yu.A. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Doyle, B.P. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, 2006 (South Africa); Nannarone, S. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Dipartimento di Ingegneria dei Materiali ed Amb., Universita di Modena e Reggio Emilia (Italy)

    2009-12-15

    The chemistry and electronic properties of the interfaces formed between the ferromagnetic metal (Fe) and the model organic semiconductor copper phthalocyanine are investigated in ultra-high vacuum conditions for the case of metal deposition onto the organic molecular thin film. The studies were performed by means of core-level and valence-band high-resolution photoemission electron spectroscopy (PES) as well as near-edge X-ray absorption fine structure using synchrotron radiation. Metal overlayer formation on the top of the organic semiconductor was observed without substantial penetration of deposited metal species into the organic film. At the thin interface layer the ferromagnetic metal shows strong chemical interaction with the nitrogen and carbon of the organic films. Moreover, our results infer that, as a consequence of Fe deposition onto CuPc, central copper atoms of the organic molecules at the interface are reduced from Cu(II) to Cu(I), while Fe atoms are oxidized and/or the ferromagnetic metal replaces this central Cu atom. Further optimization of such an interface is thus required to allow and/or facilitate the injection of spin-polarized carriers into organic semiconductors. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  10. Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

    CERN Document Server

    Ghosh, S; Petrelli, A; Kriegel, I; Gaspari, R; Almeida, G; Bertoni, G; Cavalli, A; Scotognella, F; Pellegrino, T; Manna, L

    2016-01-01

    We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor ce...

  11. Phase and microstructure of TbCu7-type SmFe melt-spun powders

    Institute of Scientific and Technical Information of China (English)

    LUO Yang; YU Dunbo; LI Hongwei; ZHUANG Weidong; LI Kuoshe; L(U) Binbin

    2013-01-01

    The SmxZr0.3Fe9.1-xCo0.6 (x=0.8,0.9,1.0) powders were prepared by melt-spun method with different quenching velocities.The phase and microstructure were studied by X-ray diffraction (XRD),scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The Th2Zn17-type structure of the as-cast state changed to TbCu7-type after quenching to a rotating molybdenum roll under certain velocity,and the formation of TbCu7-type phase was strictly depending on the Sm content and roll speed.The SEM morphology showed that the Fe-rich zone was typically fish-bone structure and TEM diffraction pattern indicated the nano-scale crystal size with TbCu7-structure when x=0.9,and FCC type γ-Fe on the basis of α-Fe formed in the non-equilibrium solidification could be detected by selected area electron diffraction (SAED) indexing in the x=0.8 samples.

  12. Effect of Hydrostatic Pressure on Superconductivity in kappa-[(BEDT-TTF)1-X(Bedse-TTF)X]2Cu[N(CN)2]Br

    OpenAIRE

    Sushko, Y. V.; Leontsev, S. O.; Korneta, O. B.; Kawamoto, A

    2005-01-01

    Static susceptibility of kappa-[(BEDT-TTF)1-x(BEDSe-TTF)x]2Cu[N(CN)2]Br alloys with the BEDSe-TTF content near the border-line of ambient pressure superconductivity (x~0.3) has been measured as a function of temperature, magnetic field, and pressure. A non-monotonic pressure dependence is observed for both the superconducting critical temperature and superconducting volume fraction, with both quantities showing growth under pressure in the initial pressure range P < 0.3 kbar. The results are ...

  13. Disorder-induced gap in the normal density of states of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br.

    Science.gov (United States)

    Diehl, Sandra; Methfessel, Torsten; Tutsch, Ulrich; Müller, Jens; Lang, Michael; Huth, Michael; Jourdan, Martin; Elmers, Hans-Joachim

    2015-07-01

    The local density of states (DOS) of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br, measured by scanning tunneling spectroscopy on in situ cleaved surfaces, reveals a logarithmic suppression near the Fermi edge persisting above the critical temperature T(c). The experimentally observed suppression of the DOS is in excellent agreement with a soft Hubbard gap as predicted by the Anderson-Hubbard model for systems with disorder. The electronic disorder also explains the diminished coherence peaks of the quasi-particle DOS below T(c).

  14. Magnetic properties of R2Fe14-xMxB, R = Y, Gd, M = Si, Cr, Cu alloys

    International Nuclear Information System (INIS)

    Structural and magnetic properties of R2Fe14-xMxB systems (R = Y, Gd, M = Si, Cr, Cu) are investigated. These compounds crystallize in a tetragonal system at P42/mnm-type for a Si content up to x = 2, Cr content up to x = 3 and for Cu concentration up to x = 1.5. The Curie temperature increases when Fe is substituted by Si and Cu, decreases when Fe is replaced by Cr. The saturation magnetization decreases with increasing content of a M element

  15. 新型六核双网兜状簇合物[MoS4Cu5Br3(Py)7]的合成与晶体结构%Synthesis and Crystal Structure of a Novel Twin Nido-like Hexanulcear Cluster[MoS4Cu5Br3(Py)7

    Institute of Scientific and Technical Information of China (English)

    陈金香; 魏振宏; 徐庆锋; 李红喜; 郎建平

    2004-01-01

    以(NH4)2[Mo2S12]·2H2O与过量CuBr在吡啶溶液中反应,得到了一个新型六核Mo/Cu/S簇合物[MoS4Cu5Br3(Py)7].X-射线单晶结构分析表明它属于三斜晶系,空间群为PīC35H35Br3Cu5MoN7S4,Mr=1335.37,a=11.6274(4),b=12.0127(4),c=18.8872(5)A,α=82.46(2),β=73.25(2),γ=62.800(13)°,V=2246.8(2)A3,Z=2,F(000)=1300.0,Dc=1.974g/cm3,μ=5.482 mm-1,5718个独立可观察点(I>3?(I)),最终偏离因子R和Rw分别为0.042和0.048.标题化合物是由2个相似的网兜状MoS3Cu3簇核通过共用MoSCuS平面形成的双网兜状结构,Mo…Cu距离在2.6830(11)~2.741(2)A之间.

  16. Thermodynamic analysis of binary Fe85B15 to quinary Fe85Si2B8P4Cu1 alloys for primary crystallizations of α-Fe in nanocrystalline soft magnetic alloys

    International Nuclear Information System (INIS)

    Fe-based Fe85B15, Fe84B15Cu1, Fe82Si2B15Cu1, Fe85Si2B12Cu1, and Fe85Si2B8P4Cu1 (NANOMET®) alloys were experimental and computational analyzed to clarify the features of NANOMET that exhibits high saturation magnetic flux density (Bs) nearly 1.9 T and low core loss than conventional nanocrystalline soft magnetic alloys. The X-ray diffraction analysis for ribbon specimens produced experimentally by melt spinning from melts revealed that the samples were almost formed into an amorphous single phase. Then, the as-quenched samples were analyzed with differential scanning calorimeter (DSC) experimentally for exothermic enthalpies of the primary and secondary crystallizations (ΔHx1 and ΔHx2) and their crystallization temperatures (Tx1 and Tx2), respectively. The ratio ΔHx1/ΔHx2 measured by DSC experimentally tended to be extremely high for the Fe85Si2B8P4Cu1 alloy, and this tendency was reproduced by the analysis with commercial software, Thermo-Calc, with database for Fe-based alloys, TCFE7 for Gibbs free energy (G) assessments. The calculations exhibit that a volume fraction (Vf) of α-Fe tends to increase from 0.56 for the Fe85B15 to 0.75 for the Fe85Si2B8P4Cu1 alloy. The computational analysis of the alloys for G of α-Fe and amorphous phases (Gα-Fe and Gamor) shows that a relationship Gα-Fe ∼ Gamor holds for the Fe85Si2B12Cu1, whereas Gα-Fe < Gamor for the Fe85Si2B8P4Cu1 alloy at Tx1 and that an extremely high Vf = 0.75 was achieved for the Fe85Si2B8P4Cu1 alloy by including 2.8 at. % Si and 4.5 at. % P into α-Fe. These computational results indicate that the Fe85Si2B8P4Cu1 alloy barely forms amorphous phase, which, in turn, leads to high Vf and resultant high Bs

  17. Non-injection synthesis of monodisperse Cu-Fe-S nanocrystals and their size dependent properties.

    Science.gov (United States)

    Gabka, Grzegorz; Bujak, Piotr; Żukrowski, Jan; Zabost, Damian; Kotwica, Kamil; Malinowska, Karolina; Ostrowski, Andrzej; Wielgus, Ireneusz; Lisowski, Wojciech; Sobczak, Janusz W; Przybylski, Marek; Pron, Adam

    2016-06-01

    It is demonstrated that ternary Cu-Fe-S nanocrystals differing in composition (from Cu-rich to Fe-rich), structure (chalcopyrite or high bornite) and size can be obtained from a mixture of CuCl, FeCl3, thiourea and oleic acid (OA) in oleylamine (OLA) using the heating up procedure. This new preparation method yields the smallest Cu-Fe-S nanocrystals ever reported to date (1.5 nm for the high bornite structure and 2.7 nm for the chalcopyrite structure). A comparative study of nanocrystals of the same composition (Cu1.6Fe1.0S2.0) but different in size (2.7 nm and 9.3 nm) revealed a pronounced quantum confinement effect, confirmed by three different techniques: UV-vis spectroscopy, cyclic voltammetry and Mössbauer spectroscopy. The optical band gap increased from 0.60 eV in the bulk material to 0.69 eV in the nanocrystals of 9.3 nm size and to 1.39 eV in nanocrystals of 2.7 nm size. The same trend was observed in the electrochemical band gaps, derived from cyclic voltammetry studies (band gaps of 0.74 eV and 1.54 eV). The quantum effect was also manifested in Mössbauer spectroscopy by an abrupt change in the spectrum from a quadrupole doublet to a Zeeman sextet below 10 K, which could be interpreted in terms of the well defined energy states in these nanoparticles, resulting from quantum confinement. The Mössbauer spectroscopic data confirmed, in addition to the results of XPS spectroscopy, the co-existence of Fe(iii) and Fe(ii) in the synthesized nanocrystals. The organic shell composition was investigated by NMR (after dissolution of the inorganic core) and IR spectroscopy. Both methods identified oleylamine (OLA) and 1-octadecene (ODE) as surfacial ligands, the latter being formed in situ via an elimination-hydrogenation reaction occurring between OLA and the nanocrystal surface. PMID:27197089

  18. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian, E-mail: chenjian@xatu.edu.cn [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Niu, Pengyun; Wei, Ting [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Hao, Liang [College of Architecture and Civil Engineering, Xi' an University of Science and Technology, Xi' an 710054 (China); Liu, Yunzi [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Wang, Xianhui, E-mail: xhwang693@xaut.edu.cn [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Peng, Yuli [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China)

    2015-11-15

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites.

  19. Development and characterization of the CU ground MAX-DOAS instrument: lowering RMS noise and first measurements of BrO, IO, and CHOCHO near Pensacola, FL

    Science.gov (United States)

    Coburn, S.; Dix, B.; Sinreich, R.; Volkamer, R.

    2011-01-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is directly proportional to the root mean square (RMS) of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS values of ~6 × 10-6 without apparent limitations other than photon shot noise. Laboratory tests revealed two factors that, in practice, limit the RMS: (1) detector non-linearity noise, RMSNLin, and (2) temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines) and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (~10-3) yet - unless actively controlled - is sufficiently large to create a RMSNLin limit of up to 1.4 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels/°C at 334 nm), and temperature variations of 0.1 °C can cause residual RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. The CU GMAX-DOAS was set up at a coastal site near Pensacola, FL, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL), with daytime average tropospheric vertical column densities, VCDs, of ~2 × 1013 molec cm-2, 8 × 1012 molec cm-2 and 4 × 1014 molec cm-2, respectively. HCHO and NO2 were also detected with typical MBL VCDs of 1 × 1016 and 3 × 1015. These are the first measurements of BrO, IO and CHOCHO over the Gulf of Mexico. The atmospheric implications of these observations for elevated mercury wet deposition rates in this area are briefly

  20. Study of polyaniline coated CuFe2O4 nanoparticles and their application in biosensor

    Science.gov (United States)

    Sharma, Uma Shankar; Shah, Rashmi

    2016-05-01

    Polyaniline coated with nanoferrite particles has attractive application in enzyme less biosensor. In this paper, we have reported the synthesis of copper ferrite by Chemical Coprecipitation method and polymerization of polyaniline by oxidation method. The polyaniline-ferrite composite was characterized by different techniques such as XRD and VSM. The XRD pattern confirmed the presence of cubic phase and particles size in nano scale. The magnetic properties were studied by vibrating sample magnetometer (VSM) technique at room temperature. The higher values of saturation magnetization attributed to the cation distribution change from normal to spinel structure. Some Fe3+ ions drifted from octahedral site to tetrahedral site through the conversion of some Fe2+ ions to Fe3+ ions with super-exchange interactions and gives rise to saturation magnetization. The saturation magnetization of polyaniline coated CuFe2O4 using ammonium nitrate is much less than by polyaniline coated CuFe2O4 using ammonium peroxidisulphate. The saturation magnetization Ms of the nanocomposite is dependent on the volume fraction of the magnetic ferrite particles and on the contribution of the non-magnetic polyaniline coated layer. Polyaniline worked as an immobilization layer in the enzyme less biosensor because enzyme less biosensor is not affected by environmental factor.

  1. Discovery of Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloys in the Zhaishang gold deposit, southern Gansu Province and its geological significance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

  2. Fe3O4/CuO/ZnO/Nano graphene platelets (Fe3O4/CuO/ZnO/NGP) composites prepared by sol-gel method with enhanced sonocatalytic activity for the removal of dye

    Science.gov (United States)

    Hendry, Tju; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this study, an attempt has been made to synthesize nanographene platelets coupled with Fe3O4/CuO/ZnO (Fe3O4/CuO/ZnO/NGP) with various ZnO loadings using a two step methods, sol-gel followed by hydrothermal method. Characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer. The sonocatalytic performance was evaluated by degradation of methylene blue under ultrasonic irradiation.The Fe3O4/CuO/ZnO/NGP showed superior sonocatalytic activity than the Fe3O4/CuO/ZnO materials. They also showed high stability and can be easily separated from the reaction system for recycling process.

  3. Preparation of Cu, Ag, Fe and Al nanoparticles by the exploding wire technique

    Indian Academy of Sciences (India)

    P Sen; Joyee Ghosh; Alqudami Abdullah; Prashant Kumar; Vandana

    2003-10-01

    We describe a novel process for the production of nanoparticles of Cu, Ag, Fe and Al which involves exploding their respective wires, triggered by large current densities in the wires. The particles are characterised by X-ray diffraction (XRD) and atomic force microscopy (AFM). Particle sizes in the range 20-100nm were obtained employing this technique. The XRD results reveal that the nanoparticles continue to retain lattice periodicity at reduced particle sizes, displaying in some cases evidence of lattice strain and preferential orientation. In the case of Fe, Mossbauer spectroscopy reveals loss of ferromagnetism as a result of the reduced size of the particles.

  4. Electronic structure and bonding in metal porphyrins, metal=Fe, Co, Ni, Cu, Zn

    OpenAIRE

    Liao, M.-S.; Scheiner, Steve

    2002-01-01

    A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as 3A2g,...

  5. A New ZrCuSiAs-Type Superconductor: ThFeAsN.

    Science.gov (United States)

    Wang, Cao; Wang, Zhi-Cheng; Mei, Yu-Xue; Li, Yu-Ke; Li, Lin; Tang, Zhang-Tu; Liu, Yi; Zhang, Pan; Zhai, Hui-Fei; Xu, Zhu-An; Cao, Guang-Han

    2016-02-24

    We report the first nitrogen-containing iron-pnictide superconductor ThFeAsN, which is synthesized by a solid-state reaction in an evacuated container. The compound crystallizes in a ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters a = 4.0367(1) Å and c = 8.5262(2) Å at 300 K. The electrical resistivity and dc magnetic susceptibility measurements indicate superconductivity at 30 K for the nominally undoped ThFeAsN.

  6. Influences of post-annealing conditions on the formation of delafossite-CuFeO2 thin films

    Science.gov (United States)

    Chen, Hong-Ying; Fu, Guan-Wei

    2014-01-01

    In this study, post-annealing conditions, the partial oxygen pressures (pO2) and temperatures, influence on the formation of delafossite-CuFeO2 thin films is studied. The sol-gel derived films were annealed at 500 °C in air and post-annealed at 500-850 °C in pO2 = 10-2 to pO2 = 5 × 10-5 atm. The CuO and CuFe2O4 phases appeared when the sol-gel derived films were post-annealed below 800 °C for 2 h in pO2 = 10-2 atm, 650 °C for 2 h in pO2 = 10-3 atm, and 550 °C for 2 h in pO2 = 5 × 10-5 atm. Pure delafossite-CuFeO2 phase was detected as specimens were post-annealed above 800 °C for 12 h in pO2 = 10-2 atm, 650 °C for 12 h in pO2 = 10-3 atm, and 550 °C for 12 h in pO2 = 5 × 10-5 atm. The surface of post-annealed thin films exhibited a nanoparticle-like morphology when the specimens exhibited CuO and CuFe2O4 phases. However, the surface revealed granular features caused by the formation of the delafossite-CuFeO2 phase. The formation of the delafossite-CuFeO2 phase, which resulted from the chemical reaction of the CuO and CuFe2O4 phases in the post-annealing process, is consistent with thermodynamics. The optical bandgaps of delafossite-CuFeO2 thin films prepared using post-annealing ranged between 3.1 and 3.2 eV. The electrical conductivities of delafossite-CuFeO2 thin films were (1.62-6.37) × 10-1 S cm-1 and the carrier concentrations were (1.52-8.84) × 1017 cm-3. The pO2 and temperatures in the post-annealing process played primary roles in the formation of delafossite-CuFeO2 thin films in this study.

  7. Enhancement of spin-Seebeck effect by inserting ultra-thin Fe{sub 70}Cu{sub 30} interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, D., E-mail: d.kikuchi@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Ishida, M.; Murakami, T. [Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Smart Energy Research Laboratories, NEC Corporation, Tsukuba 305-8501 (Japan); Uchida, K. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Qiu, Z. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Saitoh, E. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0076 (Japan)

    2015-02-23

    We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe{sub 70}Cu{sub 30}/BiY{sub 2}Fe{sub 5}O{sub 12} (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe{sub 70}Cu{sub 30} interlayer. This enhancement decays sharply with increasing the Fe{sub 70}Cu{sub 30} thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe{sub 70}Cu{sub 30} interlayer. Combined with control experiments using Pt/Fe{sub 70}Cu{sub 30} devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe{sub 70}Cu{sub 30}/BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

  8. Technological Study of Electroless Ni-Cu-P Alloy Plating on Nd-Fe-B Magnet%Nd-Fe-B永磁体化学镀Ni-Cu-P工艺研究

    Institute of Scientific and Technical Information of China (English)

    于升学; 杨雪梅; 杨洪生

    2002-01-01

    本文研究了烧结型Nd-Fe-B永磁体化学镀Ni-Cu-P的工艺过程,Nd-Fe-B永磁体经除油、封孔、出光后直接化学镀Ni-Cu-P合金,可以获得与基体结合良好、耐蚀性高的镀层.

  9. Interacting spin-1/2 tetrahedral system Cu2Te2O5X2 (X = Cl, Br)

    DEFF Research Database (Denmark)

    Jensen, Jens

    2009-01-01

    Magnetic ordering and excitations of Cu2Te2O5Cl2 are analyzed in terms of a tetramerized spin model for the tetrahedral Cu clusters of spin 1/2. The mean-field model is able to account for the main properties of the incommensurable magnetic structure observed by Zaharko et al. [Phys. Rev. B 73, 0...

  10. Synthesis and characterization of hardened Cu-Fe-Ni-P alloy

    Directory of Open Access Journals (Sweden)

    G. Brovč

    2015-01-01

    Full Text Available In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be, and desire to avoid the alloying with precious metals (Ag has created a need for new alloys with good electrical conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was followed by 4 point D.C. electrical resistivity measuring method, and analyzed by scanning (SEM and transmission (TEM electron microscopy. Measurements of Vickers hardness and electrical conductivity after various heat treatment procedures indicate on high potential of Cu-Fe-Ni-P alloys as a material for electrical contacts.

  11. THERMODYNAMICS OF FE-CU ALLOYS AS DESCRIBED BY A CLASSIC POTENTIALS

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A; Caro, M; Lopasso, E M; Turchi, P A; Farkas, D

    2005-04-14

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. (Modelling Simul. Mater. Sci. Eng. 6, 19 (1998)). In this work we extract thermodynamic information from this interatomic potentials. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials; finally we suggest an approach to improve existing potentials for this system.

  12. Surfactant-assisted epitaxial growth and magnetism of Fe films on Cu(111)

    Energy Technology Data Exchange (ETDEWEB)

    Nino, M A; Camarero, J; Miguel, J J de; Miranda, R [Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales ' Nicolas Cabrera' , Universidad Autonoma de Madrid, Cantoblanco, 28049-Madrid (Spain); Gomez, L [Facultad de Ciencias Exactas, IngenierIa y Agrimensura, Instituto de Fisica Rosario, 2000-Rosario (Argentina); Ferron, J [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Departamento de Materiales, Facultad de IngenierIa Quimica, UNL, 3000 Santa Fe (Argentina)

    2008-07-02

    The magnetic properties of thin epitaxial layers of Fe grown on Cu(111) depend sensitively on the films' structure and morphology. A combination of experiments and numerical simulations reveals that the use of a surfactant monolayer (ML) of Pb during molecular beam epitaxy (MBE) growth at room temperature reduces the amount of interdiffusion at the Cu-Fe interface, retards the fcc-to-bcc transformation by about 2 ML and substantially increases the films' coercivity. The origin of all these alterations to the magnetic behavior can be traced back to the structural modifications provoked by the surfactant during the early growth stages. These results open the way for the controlled fabrication of custom-designed materials with specific magnetic characteristics.

  13. Study of structural and optical properties of Fe doped CuO nanoparticles

    Science.gov (United States)

    Rani, Poonam; Gupta, Ankita; Kaur, Sarabjeet; Singh, Vishal; Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    Iron doped Copper oxide nanoparticles were synthesized by the co-precipitation method at different concentration (3%, 6%, 9%) at 300-400° C with Copper Acetate and Ferric Chloride as precursors in presence of Polyethylene Glycol and Sodium Hydroxide as stabilizing agent. Effect of doping on the structural and optical properties is studied. The obtained nanoparticles were characterized by X-Ray Diffraction and UV-Visible Spectroscopy for examining the size and the band gap respectively. The X-Ray Diffraction plots confirmed the monoclinic structure of Copper oxide suggesting the Cu atoms replaced by Fe atoms and no secondary phase was detected. The indirect band gap of Fe doped CuO nanoparticles is 2.4eV and increases to 3.4eV as the concentration of dopant increases. The majority of particle size is in range 8 nm to 35.55 nm investigated by X-ray diffractometer.

  14. Synthesis and Magnetic Properties of CuFe2O4 Nanotube Arrays

    Institute of Scientific and Technical Information of China (English)

    GAO Hua; GAO Daqiang; ZHANG Jing; YANG Guijin; ZHANG Jinlin; SHI Zhenhua; XUE Desheng

    2012-01-01

    CuFe2O4 nanotube arrays with different outer diameters were synthesized in anodic aluminum oxide templates through sol-gel techniques followed by heating treatment processes.The morphology of the nanotube arrays was investigated by field emission scanning electron microscope and transmission electron microscopy,suggesting that the nanotube arrays are ordered and uniform.The X-ray diffraction results indicate that the crystal structure of the nanotube arrays is polycrystalline with a spinel-type structure.The measurements of magnetic properties indicate that CuFe2O4 nanotube arrays with outer diameter of 200 nm exhibit magnetic anisotropy with easy magnetization direction along the axis of nanotubes.

  15. Evaluation of Fracture Toughness of Al-Cu-Fe-B Quasicrystal

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi-ying; LI Pei-yao; QIAN Shi-qiang

    2003-01-01

    Vickers indentation test,a simple method for the toughness determination,is used to test the fracture toughness of Al59Cu25.5Fe12.5B3 polycrystalline quasicrystal.According to the profiles of the indentation,the radial crack size and related equation,the microhardness Hv, Young's modulus E,cracking threshold,and fracture toughness have been evaluated.The results show that the Young's modulus of Al-Cu-Fe-B polycrystalline quasicrystal is evaluated as 134GPa,and the fracture toughness is about 1.36 MPa*m-1/2.For the Vickers indenter,the cracking threshold is in the range of 250MN-500MN.Moreover,the surface morphology of the indentations and the cracks are observed by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM).The relationship between the microstructure of quasicrystal and crack initiation and propagation is discussed in detail.

  16. Selective hydrogen gas sensor using CuFe2O4 nanoparticle based thin film

    Science.gov (United States)

    Haija, Mohammad Abu; Ayesh, Ahmad I.; Ahmed, Sadiqa; Katsiotis, Marios S.

    2016-04-01

    Hydrogen gas sensors based on CuFe2O4 nanoparticle thin films are presented in this work. Each gas sensor was prepared by depositing CuFe2O4 thin film on a glass substrate by dc sputtering inside a high vacuum chamber. Argon inert gas was used to sputter the material from a composite sputtering target. Interdigitated metal electrodes were deposited on top of the thin films by thermal evaporation and shadow masking. The produced sensors were tested against hydrogen, hydrogen sulfide, and ethylene gases where they were found to be selective for hydrogen. The sensitivity of the produced sensors was maximum for hydrogen gas at 50 °C. In addition, the produced sensors exhibit linear response signal for hydrogen gas with concentrations up to 5%. Those sensors have potential to be used for industrial applications because of their low power requirement, functionality at low temperatures, and low production cost.

  17. Revised magnetic properties of CuFeO{sub 2}-a case of mistaken identity

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, O A [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Lees, M R [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Balakrishnan, G [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Brion, S de [Grenoble High Magnetic Field Laboratory, CNRS and MPI-FKF, BP166, 38042 Grenoble Cedex 9 (France); Chouteau, G [Grenoble High Magnetic Field Laboratory, CNRS and MPI-FKF, BP166, 38042 Grenoble Cedex 9 (France)

    2005-05-04

    We propose a new model for the understanding of the magnetic properties of CuFeO{sub 2}, which differs significantly from the generally accepted two-dimensional Ising model. We show that a Heisenberg model with a relatively weak anisotropy gives a much better description of all the magnetic data available for CuFeO{sub 2}. The model is self-consistent; it allows one to determine for the first time a set of parameters for the exchange interactions and magnetic anisotropy in this frustrated magnetic system. The model is backed up by single-crystal measurements of susceptibility, magnetization and specific heat as a function of magnetic field and temperature.

  18. Dilute Magnetic Semiconductor Cu2FeSnS4 Nanocrystals with a Novel Zincblende Structure

    Directory of Open Access Journals (Sweden)

    Xiaolu Liang

    2012-01-01

    Full Text Available Diluted magnetic semiconductor Cu2FeSnS4 nanocrystals with a novel zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+ ions occupy the same position in the zincblende unit cell, and their occupancy possibilities are 1/2, 1/4, and 1/4, respectively. The nanocrystals were characterized by means of X-ray diffraction (XRD, transmission electron microscopy (TEM, selected area electron diffraction (SAED, energy-dispersive spectroscopy (EDS, and UV-vis-NIR absorption spectroscopy. The nanocrystals have an average size of 7.5 nm and a band gap of 1.1 eV and show a weak ferromagnetic behavior at low temperature.

  19. Enthalpy of formation of quasicrystalline phase and ternary solid solutions in the Al-Fe-Cu system

    Institute of Scientific and Technical Information of China (English)

    I.A. Tomilin; S.D. Kaloshkin; V. V. Tcherdyntsev

    2006-01-01

    Standard enthalpies of formation of quasicrystalline phase and the ternary solid solutions in the Al-Fe-Cu system and the intermetallic compound FeAl were determined by the means of solution calorimetry. The quasicrystalline phase was prepared using two different methods. The first method (Ⅰ) consisted of ball milling the mixture of powders of pure aluminum copper and iron in a planetary mill with subsequent compacting by hot pressing and annealing. The second method (Ⅱ) consisted of arc melting of the components in argon atmosphere followed by annealing. The latter method was used for preparing the compound FeAl and the solid solutions. The phases were identified using the XRD method. The enthalpy of the formation was determined for the quasicrystalline phase of the composition Al62Cu25.5Fe12.5 and the ternary BCC solid solutions Al35Cu14Fe51, Al40Cu17Fe43, and Al50.4Cu19.6Fe30. The measured enthalpy of formation of the intermetallic com pound FeAl is in good agreement with the earlier published data. The enthaipies of formation of the quasicrystalline phases prepared using two different methods are close to each other, namely, -22.7±3.4 (method Ⅰ) and -21.3±2.1 (method Ⅱ)k J/mol.

  20. Synthesis and characterization of hardened Cu-Fe-Ni-P alloy

    OpenAIRE

    Brovč, G.; Dražič, G.; B. Karpe; Djordjević, I.; Lojen, G.; B. Kosec; M. Bizjak

    2015-01-01

    In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be), and desire to avoid the alloying with precious metals (Ag) has created a need for new alloys with good electrical conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was f...

  1. Density Of The Copper-Rich Cu-Pb-Fe Alloys

    OpenAIRE

    Sak T.; Kucharski M.

    2015-01-01

    Density of the copper-rich corner of the ternary Cu-Pb-Fe alloys was determined with the dilatometric method. Investigated alloys had constant copper content equal to 0.9, 0.8 and 0.7 mole fraction, and varied iron concentration up to 0.1 mole fraction. A model predicting the density of ternary solution from knowledge of density of pure component and the excess of molar volume for limiting binaries is proposed.

  2. Density Of The Copper-Rich Cu-Pb-Fe Alloys

    Directory of Open Access Journals (Sweden)

    Sak T.

    2015-09-01

    Full Text Available Density of the copper-rich corner of the ternary Cu-Pb-Fe alloys was determined with the dilatometric method. Investigated alloys had constant copper content equal to 0.9, 0.8 and 0.7 mole fraction, and varied iron concentration up to 0.1 mole fraction. A model predicting the density of ternary solution from knowledge of density of pure component and the excess of molar volume for limiting binaries is proposed.

  3. Structural ordering of laser-processed FePdCu thin alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Perzanowski, Marcin, E-mail: Marcin.Perzanowski@ifj.edu.pl; Krupinski, Michal; Zarzycki, Arkadiusz; Zabila, Yevhen; Marszalek, Marta

    2015-10-15

    The Cu/Fe/Pd multilayers were transformed into L1{sub 0}-ordered FePdCu alloy by pulsed laser annealing. The initial multilayers were irradiated with 1, 10, 100, and 1000 laser pulses with duration time of 10 ns and energy density of 235 mJ/cm{sup 2}. The gradual change of the number of laser pulses allowed to investigate the structural and magnetic properties at early stages of the transformation and L1{sub 0}-ordering processes. The measurements were carried out using X-Ray Diffraction, SQUID magnetometry, and Magnetic Force Microscopy. We found that L1{sub 0} FePdCu (111)-oriented nanograins are formed by ordering of the coherent domains present in the as-deposited multilayer. The irradiation does not change the vertical size of the (111) crystallites. The L1{sub 0} (002)-oriented grains appear at the later stages of the transformation and their size increases with the number of applied laser pulses. Additionally, the laser annealing induces the magnetic ordering of the irradiated material, which was observed as an increase of the saturation magnetisation and the Curie temperature with the rising number of pulses. We also observed, that irradiation with 1000 pulses leads to the loss of order, which is reflected in the drop of the Curie temperature. - Highlights: • L1{sub 0}-ordered FePdCu alloy successfully fabricated by laser annealing. • The mechanism of (111) and (002) nanocrystallite formation was different. • Gradual change of annealing conditions showed early stages of transformation. • Saturation magnetisation and Curie temperature increased with the number of pulses.

  4. FMR Investigation of the nanocrystalline FeCuNbSiB glass-covered wires

    International Nuclear Information System (INIS)

    The evolution of magnetic anisotropy and magnetization mechanisms during nanocrystalline phase formation and crystallization of Fe73.5Cu1Nb3Si13.5B9 glass-covered wires are studied by ferromagnetic resonance. The modifications of the magnetic anisotropy due to structural changes are determined from the main resonance peaks. Changes in the magnetization processes are revealed by the low field peaks detected for all samples

  5. Pressure stress-impedance effect in FeCuNbSiB amorphours ribbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The stress-impedance effect in Fe73.5Cu1Nb3Si13.5B9 (at%) ribbons is measured to investigate the influences of vacuum annealing and pressure stress. The results can be explained by the influence of induced anisotropy in the magnetization processes at the chosen drive current frequency of 90 MHz. The maximum SI% value of the ribbon annealed at 300 ℃ is 2.52%.

  6. Hot extrusion for Al-Si-(Fe, Cu) hyper-eutectic cast alloys

    OpenAIRE

    Yokoyama, Hisanaga; Umezawa, Osamu; Nagai, Kotobu; Kokubo, Kunio

    1999-01-01

    For hyper-eutectic Al-Si-(Fe, Cu) cast materials in large scale ingots, we have studied microstructural modification by thermomechanical treatment to produce a heavily deformable material. Cast materials contained coarse primary Si crystals in a few hundred micron diameter or acicular intermetallic compound in several hundred micron length. Even by multiple-step cold-rolling, sample fracture of the cast alloys occurred with more extrusion step to the cast materials. A novel process, repeated ...

  7. Mechanical properties of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials

    OpenAIRE

    Umezawa, Osamu

    2005-01-01

    Tensile and high-cycle fatigue behavior of thermomechanical treated hyper-eutectic Al-Si-(Fe, Mn, Cu) materials were studied. Through the repeated thermomechanical treatment (RTMT) which is a repeat of the multi steps cold-working followed by heat treatment, Si crystals and/or intermetallic compounds were broken into some fragments and dispersed in the aluminum matrix. Fine dispersion of the second phase particles exhibited good ductility, since early fracture was overcome. A few large Si cry...

  8. Relaxation process of Fe(CuNb)SiB amorphous alloys investigated by dynamical calorimetry

    OpenAIRE

    Zhu, J.; Clavaguera-Mora, M. T.; Clavaguera, N.

    1997-01-01

    Differential scanning calorimetry and dynamic differential scanning calorimetry were used to analyze the relaxation process of Fe(CuNb)SiB amorphous alloys. The Curie temperature(TC) evolution of the amorphous phase during relaxation as a function of heating rate, time and pre-annealing temperature were measured. Two distinct relaxation processes are observed, consequent with topological and chemical short range order changes.

  9. Magnetic and mechanical properties in FeXSiB (X = Cu, Zr, Co) amorphous alloys

    OpenAIRE

    P. Kwapuliński; Rasek, J.; Z. Stokłosa; G. Badura; B. Kostrubiec; Haneczok, G.

    2008-01-01

    Purpose: The idea of the paper is to study the influence of different alloying additions (Cu, Zr, Nb) on structuralrelaxation, crystallization, and improvement of soft magnetic properties in amorphous alloys of the type FeXSiBobtained by melt spinning technique.Design/methodology/approach: Magnetic and electric characteristics of the as quenched and successivelyannealed samples were determined at room temperature. Experiments were carried out by applying magneticpermeability measurements (Max...

  10. Domain wall pinning in FeCoCu bamboo-like nanowires

    OpenAIRE

    Berganza, Eider; Bran, Cristina; Vazquez, Manuel; Asenjo, Agustina

    2015-01-01

    The pinning effect of the periodic diameter modulations on the domain wall propagation in FeCoCu individual nanowires is determined by Magnetic Force Microscopy, MFM. A main bistable magnetic configuration is firstly concluded from MFM images characterized by the spin reversal between two nearly single domain states with opposite axial magnetization. Complementary micromagnetic simulations confirm a vortex mediated magnetization reversal process. A refined MFM imaging procedure under variable...

  11. Relaxation process of Fe(CuNb)SiB amorphous alloys investigated by dynamical calorimetry

    International Nuclear Information System (INIS)

    Differential scanning calorimetry and dynamic differential scanning calorimetry were used to analyze the relaxation process of Fe(CuNb)SiB amorphous alloys. The Curie temperature (TC) evolution of the amorphous phase during relaxation as a function of heating rate, time and pre-annealing temperature were measured. Two distinct relaxation processes are observed, consequent with topological and chemical short range order changes. copyright 1997 American Institute of Physics

  12. Sonocatalytic Methylene Blue in The Presence of Fe3O4-CuO-TiO2 Nanocomposites Heterostructure

    Science.gov (United States)

    Fauzian, Malleo; Jalaludin, Shofianina; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this work, the emphasis was mainly placed on investigating the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The prepared samples were characterized by X-ray diffraction (XRD), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller (BET) Surface Area Analysis. Methylene blue dye was selected to examine the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The degradation reaction processes were monitored by UV-vis spectrophotometer. The influence on the activity of the Fe3O4-CuO-TiO2 nanocomposites heterostructure such as TiO2 loading was studied. The sonocatalyst Fe3O4-CuO-TiO2 with molar ratio of 1:1:5 showed the highest sonocatalytic activity. At last, the experiment also indicated that holes are the main reactive species in the photodegradation mechanism in methylene blue.

  13. Determination of Fe, Cu and Zn in sugar-cane spirits commercialized in Southeastern Brazil by TXRF

    International Nuclear Information System (INIS)

    Total reflection X-ray fluorescence (TXRF) was used to determine simultaneously the concentration of Cu, Fe and Zn in seven sugar-cane spirit samples ('aguardente'), a processed alcoholic beverage made from the fermentation and distillation of sugar-cane juice. The limits of detection ranged from 35 to 8 ng x ml-1 for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As and Se. Excluding Fe, Cu and Zn, the concentrations were below their limits. Two samples showed Cu concentrations higher than the value allowed by Brazilian legislation (5 μg x ml-1), and concerning Fe and Zn, no sample were above the limits permitted by WHO for drinking water (2 and 3 μg x ml-1, respectively). (author)

  14. Cavitation Erosion Behavior of as-Welded Cu12Mn8Al3Fe2Ni Alloy

    Institute of Scientific and Technical Information of China (English)

    Xiaoya LI; Yonggui YAN; Zhenming XU; Jianguo LI

    2004-01-01

    Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance of the as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass loss and the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysis of eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-welded one. Microcracks causing cavitation damage initiate at the phase boundaries.

  15. Synthesis of copper–ferrous (CuFe) nanowires via electrochemical method and its investigations as a fluid sensor

    Indian Academy of Sciences (India)

    Saleem Khan; Sandeep Arya; Parveen Lehana; Suresh Kumar

    2014-06-01

    The special behaviour of nanowires with respect to electrical conductivity makes them suitable for sensing application. In this paper, we present a copper–ferrous (CuFe) nanowires based sensor for detection of chemicals. CuFe nanowires were synthesized by template-assisted electrochemical method. By optimizing the deposition parameters, continuous nanowires on a copper substrate were synthesized. The morphological and structural studies of the synthesized CuFe nanowires were carried out using scanning electron microscope (SEM) and X-ray diffraction (XRD). Substrates containing CuFe nanowires were moulded to form a capacitor. Different chemicals were used as dielectric in the capacitor which showed that the capacitance was a nonlinear function of the dielectric constant of fluid unlike the linear relation shown by conventional capacitors. This unique property of the nanowires based capacitors may be utilized for developing fluid sensors with improved sensitivity.

  16. The effect of production conditions on superparamagnetic properties of the FeCrMoCuNbSiB alloys

    International Nuclear Information System (INIS)

    The aim of this investigation was to choose the chemical composition and to determine the heat treatment conditions for the nanocrystalline Fe72.5-xCrxMo1Cu1Nb3Si13.5B9 (x = 4 or 6) and Fe65Cr7Mo1Cu1Nb3Si12B10.5 alloys in order to get the lowest possible temperature of transition (TC) from the ferromagnetic to superparamagnetic state. On the basis of magnetic and Moessbauer measurements it was found that the temperatures of transition from ferromagnetic to superparamagnetic state in Fe66.5Cr6Mo1Cu1Nb3Si13.5B9 and Fe65.5Cr7Mo1Cu1Nb3Si12B10.5 alloys were 450 K and 424 K, respectively. (author)

  17. (Al63Cu25Fe12)p/A356 aluminum alloy composites prepared by spray co-deposition

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-ping; XU Zhou

    2006-01-01

    A novel Al-based composite material (Al63Cu25Fe12)p/A356 was prepared by spray co-deposition. It is revealed that the reinforcement of Al63Cu25Fe12 quasicrystalline particles disperses uniformly in the composite with small crystalline grain structure of about 10 μm. The reaction between the Al63Cu25Fe12 quasicrystalline particle and the matrix metal is constrained or depressed because of the high cooling velocity in the process of spray co-deposition. Compared with the composite reinforced by non-continuous ceramics particle, the aging harden behavior of the composites of (Al63Cu25Fe12)p/A356 has outstanding characteristics with less time on aging peak happening and with higher hardening rate. The mechanical properties of the composites evidently enhance except plastic strain.

  18. Industrialization of nanocrystalline Fe-Si-B-P-Cu alloys for high magnetic flux density cores

    Science.gov (United States)

    Takenaka, Kana; Setyawan, Albertus D.; Sharma, Parmanand; Nishiyama, Nobuyuki; Makino, Akihiro

    2016-03-01

    Nanocrystalline Fe-Si-B-P-Cu alloys exhibit high saturation magnetic flux density (Bs) and extremely low magnetic core loss (W), simultaneously. Low amorphous-forming ability of these alloys hinders their application potential in power transformers and motors. Here we report a solution to this problem. Minor addition of C is found to be effective in increasing the amorphous-forming ability of Fe-Si-B-P-Cu alloys. It allows fabrication of 120 mm wide ribbons (which was limited to less than 40 mm) without noticeable degradation in magnetic properties. The nanocrystalline (Fe85.7Si0.5B9.5P3.5Cu0.8)99C1 ribbons exhibit low coercivity (Hc)~4.5 A/m, high Bs~1.83 T and low W~0.27 W/kg (@ 1.5 T and 50 Hz). Success in fabrication of long (60-100 m) and wide (~120 mm) ribbons, which are made up of low cost elements is promising for mass production of energy efficient high power transformers and motors

  19. Theoretical Scanning Tunnelling Microscopy Images of Metal (Fe, Co, Ni and Cu) Phthalocyanines

    Institute of Scientific and Technical Information of China (English)

    李群祥; 朱清时; 袁岚峰; 杨金龙; 侯建国

    2001-01-01

    The scanning tunnelling microscopy (STM) images of isolated iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), nickel phthalocyanine (NiPc) and copper phthalocyanine (CuPc) are simulated theoretically. All the simulated STM images show submolecular structures and reproduce well the features of the experimental images. The results show that there is a strong dependence of the STM images on the ion valence configuration of the metal ion. At the small tip bias voltages of less than 0.5 V, the central metal ions in NiPc and CuPc appear as holes in the molecular images, while they are the highlighted bumps in FePc and CoPc. The simulated images are interpreted by the fact that both FePc and CoPc systems have a significant dz2 character near the Fermi level while the NiPc and CuPc systems do not. Moreover, we predict that the central nickel ion for NiPc appears as a highlighted point when the tip bias voltage is larger than 0.7 V.

  20. Identification of Extra-Framework Species on Fe/ZSM-5 and Cu/ZSM-5 Catalysts Typical Microporous Molecular Sieves with Zeolitic Structure

    OpenAIRE

    Urquieta-González E.A.; Martins L; Peguin R.P.S.; Batista M.S.

    2002-01-01

    Cu and Fe species formed during the preparation of Cu/ and Fe/ZSM-5 catalysts by ion exchange were studied. XRD, SEM, H2-TPR, DRS-UV-VIS, EPR, Mössbauer Spectroscopy (MÖSS) and chemical analysis (AAS) were used to sample characterization. Cu/ZSM-5 catalysts, irrespective of their Si/Al ratio and Cu content, showed a reduction peak at around 210°C, which was attributed to the reduction of Cu+2 to Cu+1. The reduction peak of Cu+1 to Cu0 shifted to higher temperatures with the increase of Si/Al ...

  1. High near-infrared absorbing Cu5FeS4 nanoparticles for dual-modal imaging and photothermal therapy

    Science.gov (United States)

    Zhao, Qi; Yi, Xuan; Li, Meifang; Zhong, Xiaoyan; Shi, Quanliang; Yang, Kai

    2016-07-01

    Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments.Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr04444a

  2. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.;

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic......-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (TC) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded...... the exponent values of beta = 0.369 +/- 0.005, gamma = 1.359 +/- 0.005 and delta = 4.7 +/- 0.1 for FCSNB-Ag, and beta = 0.376 +/- 0.002, gamma = 1.315 +/- 0.006 and delta = 4.5 +/- 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D...

  3. Thermal Stability and Reductive Property of CexZr1-xO2 Solid Solution Doped Simultaneously by Fe, Mn or Fe, Cu

    Institute of Scientific and Technical Information of China (English)

    Yan Zhongjun; Yang Dong; Wen Mingfen; Chen Jing; Wang Jinggang; Gu Yongwan

    2005-01-01

    CexZr1-xO2 complex oxides doped by transition metal(Fe, Mn, Cu) were prepared by precipitation method. Thermal stability of samples was characterized by XRD, surface areas were measured by BET method and reductive property was characterized by TPR. The results show that MnO2 can be dispersed in solid solution after calcined at 1273 K, when the loading is 12%, while Fe and Cu is easy to separate from samples at this temperature. Samples doped simultaneously by Fe, Mn or Fe, Cu demonstrated high reactive property at low temperature. The starting reduction temperature are 413 and 373 K, respectively. TPR results also show a broad range of reductive temperature exists in these bi-metal doped samples.

  4. Structure and thermodynamic properties of (C5H12N)CuBr3: a new weakly coupled antiferromagnetic spin-1/2 chain complex lying in the 1D-3D dimensional cross-over regime.

    Science.gov (United States)

    Pan, Bingying; Wang, Yang; Zhang, Lijuan; Li, Shiyan

    2014-04-01

    Single crystals of a metal organic complex (C5H12N)CuBr3 (C5H12N = piperidinium, pipH for short) have been synthesized, and the structure was determined by single-crystal X-ray diffraction. (pipH)CuBr3 crystallizes in the monoclinic group C2/c. Edging-sharing CuBr5 units link to form zigzag chains along the c axis, and the neighboring Cu(II) ions with spin-1/2 are bridged by bibromide ions. Magnetic susceptibility data down to 1.8 K can be well fitted by the Bonner-Fisher formula for the antiferromagnetic spin-1/2 chain, giving the intrachain magnetic coupling constant J ≈ -17 K. At zero field, (pipH)CuBr3 shows three-dimensional (3D) order below TN = 1.68 K. Calculated by the mean-field theory, the interchain coupling constant J' = -0.91 K is obtained and the ordered magnetic moment m0 is about 0.23 μB. This value of m0 makes (pipH)CuBr3 a rare compound suitable to study the 1D-3D dimensional cross-over problem in magnetism, since both 3D order and one-dimensional (1D) quantum fluctuations are prominent. In addition, specific heat measurements reveal two successive magnetic transitions with lowering temperature when external field μ0H ≥ 3 T is applied along the a' axis. The μ0H-T phase diagram of (pipH)CuBr3 is roughly constructed. PMID:24617285

  5. Effects of Fe content on the microstructure and properties of CuNi10FeMn1 alloy tubes fabricated by HCCM horizontal continuous casting

    Science.gov (United States)

    Jiang, Yan-bin; Xu, Jun; Liu, Xin-hua; Xie, Jian-xin

    2016-04-01

    Heating-cooling combined mold (HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuNi10FeMn1 alloy tubes with different Fe contents. The effects of Fe content (1.08wt%-2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.

  6. X-ray emission spectra and gaps of CuFeO2 with the modified Becke–Johnson potential

    International Nuclear Information System (INIS)

    We investigate the electronic structures of CuFeO2 by using Tran and Blaha's modified Becke and Johnson exchange potential. The calculated X-ray emission spectra of CuFeO2 for O–K and Fe–L are quite compatible with experimental data. The calculated energy band gap and optical band gap are 0.15 eV and 1.03 eV, respectively, and the theoretical magnetic moment for Fe atom is 4.11μB, which is very close to experimental value 4.2±0.1μB. - Highlights: • Calculated electronic structures show CuFeO2 as a narrow gap semiconductor. • Calculated X-ray emission spectra for O–K and Fe–L are quite compatible with experimental data. • Calculated magnetic moment of the Fe ion agrees well with reported experimental value

  7. Preliminary Evaluation of the Thermally Affected Metallurgical Condition of Extruded and Drawn CuFe2P Tubes

    Science.gov (United States)

    Pantazopoulos, George; Toulfatzis, Anagnostis; Zormalia, Sylvia; Vazdirvanidis, Athanasios; Skarmoutsos, Dionysios

    2012-10-01

    The influence of heat treatment conditions on the mechanical behavior and microstructure of CuFe2P (ASTM C19400) in comparison to deoxidized-high-phosphorus (DHP-Cu/ASTM C12200) tubes was investigated. The aim of this study was the enhancement of understanding of microstructure/thermal treatment/strength relationships which could be further utilized for the manufacturing of components exhibiting superior performance and reliability for refrigeration and heat exchanger applications. Microstructural examination employing optical metallography and scanning electron microscopy is used for the evaluation of the recrystallization progress and grain growth processes. In addition, tensile testing was conducted to CuFe2P and DHP tubes following the application of heat treatment cycles, in accordance to the EN 10002-1 specifications. Mechanical properties and microstructure evaluation showed that CuFe2P material is fully recrystallized at 740 °C and DHP at 400 °C for 20 min. Recrystallization initiation varies within the range of 640-660 °C for CuFe2P and below 400 °C for DHP tubes. The tensile strength of the CuFe2P tube decreased from 513 to 367 MPa, the hardness was reduced from 144 to 126 HV, while tensile elongation was significantly improved from 3 to 17%. At 640 °C, only isolated recrystallized areas were evident mainly at the Fe-based intermetallic particle/copper matrix interface areas.

  8. Effect of Cu addition on the GFA, structure and properties of Fe-Co-based alloy

    Directory of Open Access Journals (Sweden)

    S. Lesz

    2012-06-01

    Full Text Available Purpose: The aim of the paper was investigation of the effect of Cu addition on GFA (Glass Forming Ability, structure, magnetic and mechanical properties of amorphous Fe-Co-B-Si-Nb alloy.Design/methodology/approach: The following experimental techniques were used: differential thermal analysis (DTA, transmission electron microscopy (TEM and X-ray diffraction (XRD method, measurements of magnetic properties (VSM method, Vickers microhardness (HV.Findings: It was shown that when Cu is added to the Fe-Co-based alloy, increase of the GFA and change of the magnetic properties was obtained.Research limitations/implications: The results can give more details to understand the relationship between structure, magnetic and mechanical properties. Thus can be useful for practical application of these alloys.Practical implications: The (Fe36Co36B19Si5Nb4100-xCux (x=0 and 0.6 metallic glasses due to their excellent soft magnetic properties have shown great industrial value for commercial application. Many products consisting of these kinds of metallic glasses have been widely used, for example anti-theft labels, precision sensor material, and high efficient magnetic transformers in electronic industry.Originality/value: The applied investigation methods are suitable to determine the changes of GFA and structure combined with magnetic and mechanical properties of (Fe36Co36B19Si5Nb4100-xCux (x=0 and 0.6 metallic glasses.

  9. Probing structure-property relationships in perpendicularly magnetized Fe/Cu(001) using MXLD and XPD

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, T.R.; Waddill, G.D. [Univ. of Missouri, Rolla, MO (United States); Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Magnetic X-ray Linear Dichroism (MXLD) in Photoelectron Spectroscopy and X-Ray Photoelectron Diffraction (XPD) of the Fe 3p core level have been used to probe the magnetic structure-property relationships of perpendicularly magnetized Fe/Cu(001), in an element-specific fashion. A strong MEXLD effect was observed in the high resolution photoelectron spectroscopy of the Fe 3p at {open_quotes}normal{close_quotes} emission and was used to follow the loss of perpendicular ferromagnetic ordering as the temperature was raised toward room temperature. In parallel with this, {open_quotes}Forward Focussing{close_quotes} in XPD was used as a direct measure of geometric structure in the overlayer. These results and the implications of their correlation will be discussed. Additionally, an investigation of the effect of Mn doping of the Fe/Cu(001) will be described. These measurements were performed at the Spectromicroscopy Facility (Beamline 7.0.1) of the Advanced Light Source.

  10. Study of Fe Zr U B and Fe Zr U Cu B nanocrystalline alloys

    Science.gov (United States)

    Sólyom, A.; Petrovič, P.; Marko, P.; Kováč, J.; Konczos, G.

    2000-06-01

    The influence of uranium and copper additives on the crystallization process and magnetic properties was studied in Fe 87Zr 7B 6 amorphous alloys. The addition of copper resulted in homogeneous nanocrystalline precipitates and improvement of soft magnetic properties. The alloying with uranium led to the formation of inhomogeneous microstructure and increase in coercive force.

  11. Study of Fe-Zr-U-B and Fe-Zr-U-Cu-B nanocrystalline alloys

    International Nuclear Information System (INIS)

    The influence of uranium and copper additives on the crystallization process and magnetic properties was studied in Fe87Zr7B6 amorphous alloys. The addition of copper resulted in homogeneous nanocrystalline precipitates and improvement of soft magnetic properties. The alloying with uranium led to the formation of inhomogeneous microstructure and increase in coercive force

  12. Estudio cinético de las reacciones de recocido en aleaciones de Cu-Ni-Fe

    Directory of Open Access Journals (Sweden)

    Donoso, Eduardo

    2014-09-01

    Full Text Available The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi3 phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi3 phase.Mediante Calorimetría Diferencial de Barrido (DSC y medidas de microdureza Vickers se ha estudiado el comportamiento durante el recocido de las aleaciones Cu-45Ni-4Fe, Cu-34Ni-11Fe y Cu-33Ni-22Fe templadas desde 1173 K. El análisis de las curvas DSC, desde temperatura ambiente hasta los 950 K, muestran la presencia de una reacción exotérmica asociada a la formación de la fase FeNi3 que nuclea a partir de una estructura modulada, y una reacción endotérmica que correspondería a la disolución de esta fase. Los parámetros cinéticos se calcularon a partir de la ecuación usual de Avrami-Erofeev, Kissinger modificado y funciones cinéticas integradas. Medidas de microdureza Vickers corroboraron la formación y disolución de fase FeNi3.

  13. Rapid solidification and dendrite growth of ternary Fe-Sn-Ge and Cu-Pb-Ge monotectic alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The phase separation and dendrite growth characteristics of ternary Fe-43.9%Sn- 10%Ge and Cu-35.5%Pb-5%Ge monotectic alloys were studied systematically by the glass fluxing method under substantial undercooling conditions. The maximum undercoolings obtained in this work are 245 and 257 K, respectively, for these two alloys. All of the solidified samples exhibit serious macrosegregation, indicating that the homogenous alloy melt is separated into two liquid phases prior to rapid solidification. The solidification structures consist of four phases including α-Fe, (Sn), FeSn and FeSn2 in Fe-43.9%Sn-10%Ge ternary alloy, whereas only (Cu) and (Pb) solid solution phases in Cu-35.5%Pb-5%Ge alloy under different undercool- ings. In the process of rapid monotectic solidification, α-Fe and (Cu) phases grow in a dendritic mode, and the transition "dendrite→monotectic cell" happens when alloy undercoolings become sufficiently large. The dendrite growth velocities of α-Fe and (Cu) phases are found to increase with undercooling according to an exponential relation.

  14. Fabrication of magnetically recyclable Fe3O4@Cu nanocomposites with high catalytic performance for the reduction of organic dyes and 4-nitrophenol

    International Nuclear Information System (INIS)

    A facile and efficient approach to synthesize Fe3O4@Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe3O4@Cu nanocomposites were characterized by Fourier Transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. In addition, the magnetic properties were determined with vibrating sample magnetometer. The surface of the Fe3O4 contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe3O4@Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe3O4@Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe3O4@Cu nanocomposites are more efficient catalysts compared with Cu nanoparticles and can easily be recovered from the reaction mixture with magnet. The cost effective and recyclable Fe3O4@Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe3O4@Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe3O4@Cu display high catalytic activity after 13 cycles

  15. Crystallographic and Low Frequency Conductivity Studies of the Spinel Systems CuFe2O4 and Cu1-xZnxGa0.1Fe1.9O4

    Institute of Scientific and Technical Information of China (English)

    A.M. Hashhash; N.N. Nikitenkov; I.P. Chernov; Yu.I. Tyurin

    2010-01-01

    Spinel solid solutions of CuFe2O4 and Cu1-xZnxGa0.1Fe1.9O4 with (0.0≤x≤0.5) are synthesized. Crystallographic phase transformation from tetragonal-to-cubic occurred at x=0.2. The derived structural parameters manifest that Zn occupies the tetrahedral A-site while Cu and Ga occupy the octahedral B-site and Fe distributes among A- and B-sites. Electrical conductivity measurements of these materials as a function of temperature and frequency revealed semiconducting behavior except CuFe2O4 sample, which has a metallic behavior at low frequency and at high frequency, metallic -to- semiconductor transition occurred as temperature increases. The metallic behavior in this sample is attributed to cation-cation interactions at B-site while, the semiconductor behavior in Cu1-xZnxGa0.1Fe1.9O4 compounds is due to the cation- anion -cation interactions at the same site in the spinel lattice. All compositions exhibit transition with change in the slope of conductivity versus temperature curve. This transition temperature (Tc) decreases linearly with increasing Zn content x. The relation of the universal exponent s with temperature gives evidence that over large polaron OLP and correlated barrier hopping CBH conduction mechanisms are presented in CuFe2O4 and Cu1-xZnxGa0.1Fe1.9O4 compounds respectively.

  16. Precipitation of coherent FeRh nanoparticles with highly suppressed magnetostructural transition temperatures in rapidly solidified (FeRh)5Cu95 alloys

    Science.gov (United States)

    Barua, Radhika; Jiang, Xiujuan; Shield, Jeff; Heiman, Don; Lewis, Laura

    2012-02-01

    Magnetostructural phase transitions have the capability of delivering large functional effects in response to small excursions in magnetic field, temperature and strain; this potential might be amplified in nanostructured systems by virtue of large surface:volume ratios. Nanoprecipitates (˜10nm) of FeRh, a well-known magnetostructural material, were studied with structural and magnetic probes in a rapidly solidified phase-separated system of (FeRh)5Cu95. Magnetization studies indicate a dramatic reduction in the magnetostructural phase transition temperature (Tt) of the nanoscaled FeRh phase relative to the bulk value (δT=Tt,Bulk - Tt,Nano = 220 K). Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) reveals a coherent orientational relationship between the FeRh (aFeRh = 3.09 å)and Cu (aCu = 3.78 å) phases. At the matrix/precipitate interface a constrained misfit strain of ɛ = 0.18 is observed. The reduction of the magnetostructural phase transition temperature and evolution of the magnetic properties with system annealing is analyzed in the context of the strain between the FeRh nanoparticles and the Cu matrix.

  17. Preparation and properties of 4. 25Cu-0.75Ni/NiFe2O4 cermet

    Institute of Scientific and Technical Information of China (English)

    LI Jie; ZHANG Gang; LAI Yan-qing; TIAN Zhong-liang; QIN Qing-wei

    2005-01-01

    4.25Cu-0.75Ni/NiFe2 O4 cermets were prepared by doping NiFe2 O4 ceramic matrix with the mixed powders of Cu and Ni or Cu-Ni alloy powder as the electrical conducting metallic elements. The effects of technological parameters, such as the adding modes of metallic elements, the ball milling time, the sintering time and the sintering temperature, on the relative density and resistivity of the cermets were studied. The results show that the resistivity of 4.25Cu-0.75Ni/NiFe2 O4 cermets decreases with increasing temperature, and has a turning point at 590 ℃, which is similar to that of NiFe2 O4 ceramic. The sintering temperature and adding modes of metallic elements have a great influence on the properties of 4. 25Cu-0. 75Ni/NiFe2O4 cermets. When the sintering temperature increases from 1 200 ℃ to 1 300 ℃, the relative density increases from 89.86% to 95.33 %0, and the resistivity at 960 ℃ decreases and Ni, the cermets of finely and uniformly dispersed metallic phase, high density and electric conductivity are obples sintered at 1 200 ℃ for 2 h, which are both better than those of the cermets prepared under the same technique conditions but with the metallic elements added as 85Cu-15Ni alloy powders.

  18. Optimization of the microstructure and properties of Co-substituted Fe-Si-B-Nb-Cu nanocrystalline soft magnetic alloys

    Science.gov (United States)

    Ohnuma, M.; Ping, D. H.; Abe, T.; Onodera, H.; Hono, K.; Yoshizawa, Y.

    2003-06-01

    The effect of Co replacement for Fe on the microstructure and soft magnetic properties of Fe78.8-xCoxNb2.6Si9B9Cu0.6 (x=5-60) nanocrystalline alloys has been studied for improving the soft magnetic properties of Fe-Si-B-Nb-Cu type alloys at a high frequency range. The magnetic anisotropy constant increases with x, but the coercivity increases when x exceeds 20, indicating that magnetic softness is degraded by replacing Fe with Co. Three-dimensional atom-probe observations have revealed that the number density of Cu-enriched clusters decreases with x, thereby decreasing the number density of the heterogeneous nucleation sites for bcc-Fe primary crystals. In addition, differential scanning calorimetry measurements show that the Cu clustering temperature shifts to a higher temperature with increasing x, suggesting that the kinetics for the Cu clustering decreases as Co content. These experimental results are discussed from the thermodynamical point of view, and the optimized Cu composition to achieve a low coercivity with 40 at % Co has been found. 2003 American Institute of Physics.

  19. Cobalt Substitution in CuFe$_{2}$O$_{4}$ spinel and its influence on the crystal structure and phonons

    OpenAIRE

    Silva, M. D. P.; F. C. Silva; Sinfrônio, F. S. M.; Paschoal, Alexandre Rocha; Silva, E. N.; Paschoal, Carlos William de Araujo

    2013-01-01

    In this work nanometric spinel Co${}_{1-x}$Cu${}_{x}$Fe${}_{2}$O${}_{4}$ powders were obtained by polymeric precursors method at several annealing temperatures between 700 and 1200 ${}^\\circ$C. The samples were characterized by means of X-ray powder diffraction, confirming the ideal inverse spinel structure for CoFe${}_{2}$O${}_{4}$ sample and the tetragonal distorted inverse spinel structure for CuFe${}_{2}$O${}_{4}$ sample. Based on FWHM evaluation, we estimated that crystallite sizes varie...

  20. Microstructure and the properties of FeCoCuNiSnx high entropy alloys

    International Nuclear Information System (INIS)

    Highlights: ► Based on a new alloying design idea, new FeCoCuNiSnx alloys are prepared. ► The crystal structure of alloys is a single FCC solution when Sn content is small. ► The elongation strain and tensile strength of the alloy reach 19.8% and 633 MPa. - Abstract: FeCoCuNiSnx high-entropy alloys (x denotes the adding the elements amount in atomic percentage) are prepared by an arc furnace. Their microstructure and mechanical properties are investigated. The results show that the alloys have a single FCC solution when Sn content is small, the microstructure of the alloys with increasing Sn content is FCC solution and Cu81Sn22 intermetallic compounds. The alloys possess the high strength and the plasticity. When Sn content is between 0.05 and 0.07, the maximum elongation strain and the maximum tensile strength can reach 19.8% and 633 MPa, respectively. The adding of Sn leads to the increase of tensile strength.

  1. Experimental Investigation and Thermodynamic Reassessment of the Cu-Fe-Si System

    Science.gov (United States)

    Zhao, Jingrui; Zhang, Lijun; Du, Yong; Xu, Honghui; Liang, Jianlie; Huang, Baiyun

    2009-08-01

    Based on a critical evaluation of experimental data available in the literature, the isothermal section at 1023 K of the Cu-Fe-Si system was measured using a combination of X-ray analysis, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) analysis, and electroprobe microanalysis (EPMA). In addition, fifteen alloys along two vertical sections at 30 and 70 at. pct Cu were subjected to differential thermal analysis (DTA), in order to provide new phase-transition temperatures. A thermodynamic modeling for the Cu-Fe-Si system was then conducted by considering reliable experimental data from the literature and the present work. All the calculated phase equilibria and thermodynamic properties agree well with the experimental ones. It is noteworthy that a stable liquid miscibility gap appears in the computed ternary phase diagrams, even though it is metastable in the three-boundary binaries. Significant improvements have been made compared with the previous assessments. The presently obtained parameters were also successfully applied to two technical cases in material design.

  2. Giant magnetoresistance, structural and magnetic properties of glass-coated Fe-Ni-Cu microwires

    International Nuclear Information System (INIS)

    Glass-coated Fe-Ni-Cu microwires prepared by Taylor's technique exhibit negative magnetoresistance (MR) of 8.15% at 77 K and 6.35% at 300 K in a magnetic field of 9.0 T. The MR is of the same origin found in the granular giant magnetoresistance (GMR) materials and is distinguishable from the giant magnetoimpedance (MI) commonly seen in soft magnetic microwires. MI displays a peak at zero field for RF currents with frequencies less than 20 MHz and it crosses over to a sharp dip at higher frequencies. This crossover is ascribed to the skin-depth-limited response primarily governed by the field dependence of the permeability. Micro-X-ray absorption near edge structure (micro-XANES) spectroscopy data were collected at the K edges of Cu, Ni and Fe and revealed that the Fe atoms in the as-cast sample are in FCC configuration and they remain in the FCC phase throughout the annealing processes. The MR decreases to ∼2.5% as the annealing temperature increases to 500 deg. C. The loss of GMR upon annealing is attributed to the growth of FCC Fe-Ni-rich magnetic particles. The increase in the Fe-Ni particle size also results in higher room temperature coercivity. When the annealing temperature is increased to 500 deg. C, a wasp-waisted hysteresis loop is observed which arises from the locking-in of the domain walls by the directional order of atoms due to diffusion under the influence of the local magnetic field. A magnetically hard glass-coated microwire with coercivity of 600 Oe is obtained after annealing at 700 deg. C for 1 h

  3. A hybrid-exchange density functional study of the bonding and electronic structure in bulk CuFeS2

    Science.gov (United States)

    Martínez-Casado, Ruth; Chen, Vincent H.-Y.; Mallia, Giuseppe; Harrison, Nicholas M.

    2016-05-01

    The geometric, electronic, and magnetic properties of bulk chalcopyrite CuFeS2 have been investigated using hybrid-exchange density functional theory calculations. The results are compared with available theoretical and experimental data. The theoretical description of the bonding and electronic structure in CuFeS2 is analyzed in detail and compared to those computed for chalcocite (CuS2) and greigite (Fe3S4). In particular, the behavior of the 3d electrons of Fe3+ is discussed in terms of the Hubbard-Anderson model in the strongly correlated regime and found to be similarly described in both materials by an on-site Coulomb repulsion (U) of ˜8.9 eV and a transfer integral (t) of ˜0.3 eV.

  4. Electrical conductivity of Cu/(10NiO-NiFe2O4) cermet inert anode for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cu/(10NiO-NiFe2O4) cermets containing mass fractions of Cu of 5%, 10%, 15% and 20% were prepared, and their electrical conductivities were measured at different temperatures. The effects of temperature and content of metal Cu on the electrical conductivity were investigated especially. The results indicate that the metallic phase Cu distributes evenly in 10NiO-NiFe2O4 ceramic matrix. The mechanism of electrical conductivity of Cu/(10NiO-NiFe2O4) cermets obeys the rule of electrical mechanism of semiconductor, the electrical conductivity for cermet containing 5% Cu increases from 2.70 to 20.41 S/cm with temperature increasing from 200 to 900 ℃. The change trend of electrical conductivity with temperature is similar with each other and it increases with increasing temperature and content of metal Cu. At 960 ℃, the electrical conductivity of cermet increases from 2.88 to 82.65 S/cm with the content of metal Cu increasing from 0 to 20%.

  5. Optimisation the magnetic properties of the (Fe1-xCox)73.5Cu1Nb3Si13.5B9 (X=10;30;40) alloys

    OpenAIRE

    Olszewski, J.; T. Raszka; D. Szewieczek

    2007-01-01

    Purpose: In this paper results of experience of influence a structure (amorphous and amorphous after structuralrelaxation) on the magnetic properties (the initial magnetic permeability μp, the magnetic permeability μin function magnetic field H, the coercive field Hc, the remanence Br and the saturation induction Bs)on (Fe1-XCoX)73.5Cu1Nb3Si13.5B9 (X=10;30;40) alloys have been presented.Design/methodology/approach: The material was obtained by the method of rapid cooling from liquid phase.The...

  6. Crystal structure of CuFe{sub 2}InSe{sub 4} from X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)], E-mail: gerzon@ula.ve; Mora, A.J. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, P.; Quintero, M. [Centro de Estudio de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2008-04-24

    The crystal structure of the semiconductor compound CuFe{sub 2}InSe{sub 4} was analyzed using X-ray powder diffraction data. The powder pattern refined by the Rietveld method was composed of 86.6% of the principal phase CuFe{sub 2}InSe{sub 4} and 13.4% of the binary phase FeSe. CuFe{sub 2}InSe{sub 4} crystallizes in the tetragonal space group I4-bar2m (no. 121), Z = 2, with unit cell parameters a = 5.7694(3) A, c = 11.495(1) A, V = 382.62(4) A{sup 3}. FeSe crystallizes in the tetragonal space group P4/nmm (no. 129), Z = 2, and a = 3.784(1) A, c 5.502(2) A, V = 78.78(4) A{sup 3}. The refinement of 28 instrumental and structural parameters led to R{sub p} = 8.2%, R{sub wp} = 10.7%, R{sub exp} = 6.7% and S = 1.7; R{sub B} = 9.9% (CuFe{sub 2}InSe{sub 4}), R{sub B} = 8.8% (FeSe) for 76 and 36 independent reflections, respectively.

  7. Development of FeSiBNbCu Nanocrystalline Soft Magnetic Alloys with High B s and Good Manufacturability

    Science.gov (United States)

    Wan, Fangpei; He, Aina; Zhang, Jianhua; Song, Jiancheng; Wang, Anding; Chang, Chuntao; Wang, Xinmin

    2016-06-01

    In order to develop Fe-based nanocrystalline soft magnetic alloys with high saturation magnetic flux density (B s) and good manufacturability, the effect of the Nb content on the thermal stability, microstructural evolution and soft magnetic properties of Fe78-x Si13B8Nb x Cu1 (x = 0, 1, 2 and 3) alloys were investigated. It is found that proper Nb addition is effective in widening the optimum annealing temperature range and refining the α-Fe grain in addition to enhancing the soft magnetic properties. For the representative Fe76 Si13B8Nb2Cu1 alloy, the effective annealing time can be over 60 min in the optimal temperature range of 500-600°C. FeSiBNbCu nanocrystalline soft magnetic alloys with desirable soft magnetic properties including high B s of 1.39 T, low coercivity (H c) of 1.5 A/m and high effective permeability (μ e) of 21,500 at 1 kHz have been developed. The enhanced soft magnetic performance and manufacturability of the FeSiBNbCu nanocrystalline alloys are attributed to the high activated energy for the precipitation of α-Fe(Si) and the second phase. These alloys with excellent performance have promising applications in electromagnetic fields like inductors.

  8. Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

    KAUST Repository

    Hassnain Jaffari, G.

    2015-12-16

    Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/Fe atom and a bulk like negligible value of coercivity over the temperature range of 5–300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

  9. Study on ethyl groups with two different orientations in [N(C2H5)4]2CuBr4

    Science.gov (United States)

    Lim, Ae Ran

    2016-06-01

    The crystal structure and phase transition temperature of [N(C2H5)4]2CuBr4 are studied using X-ray diffraction and differential scanning calorimetry (DSC); measurements revealed a tetragonal structure and the two phase transition temperatures TC of 204 K and 255.5 K. The structural geometry near TC is discussed in terms of the chemical shifts for 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) and 13C cross-polarization (CP)/MAS NMR. The two inequivalent ethyl groups are distinguishable by the 13C NMR spectrum. The molecular motions are discussed in terms of the spin-lattice relaxation times T1ρ in the rotating frame for 1H MAS NMR and 13C CP/MAS NMR. The T1ρ results reveal that the ethyl groups undergo tumbling motion, and furthermore that the ethyl groups are highly mobile.

  10. Effect of Ag micro-alloying on the microstructure and properties of Cu-14Fe in situ composite

    International Nuclear Information System (INIS)

    This paper studied Ag micro-alloying in the deformation-processed Cu-14Fe in situ composite, by a comparison of Cu-14Fe and Cu-14Fe-0.06Ag. Each alloy was prepared by casting and processed into an in situ composite by hot and cold working. The microstructures were documented using light microscopy and scanning electron microscopy (SEM). The mechanical properties were measured with a tensile-testing machine. The electrical conductivity was measured with a micro-ohmmeter. For both alloys, the as-cast microstructure consisted of a Cu matrix and Fe dendrites; after hot and cold working the microstructure consisted of a Cu matrix containing Fe fibres elongated in the working direction. The as-cast Ag-containing alloy contained finer Fe dendrites. The Ag-containing in situ composite had thinner Fe fibres, higher tensile strength, higher ductility, and higher conductivity. The cold worked Cu-14Fe-0.06Ag in situ composite with cumulative cold deformation strain η = 7.8 (where η = ln(A0/A) and A0 and A are the original and final cross-section areas, respectively), achieved a tensile strength of 930 MPa and a conductivity of 56%IACS (International Annealed Copper Standard; 17.241 nΩ m is defined as 100%IACS). The Ag micro-alloyed in situ composite had a combination of properties comparable to that of a much more expensive alloy containing much more Ag. After 1 h heat treatment at 300 deg. C, the tensile strength was increased to 950 MPa and the conductivity was increased to 56.4%IACS.

  11. Room temperature deposition of amorphous p-type CuFeO$_2$ and fabrication of CuFeO$_2$/n-Si heterojunction by RF sputtering method

    Indian Academy of Sciences (India)

    TAO ZHU; ZANHONG DENG; XIAODONG FANG; WEIWEI DONG; JINGZHEN SHAO; RUHUA TAO; SHIMAO WANG

    2016-06-01

    Transparent conducting amorphous p-type CuFeO$_2$ (CFO) thin film was prepared by radio-frequency (RF) magnetron sputtering method at room temperature using polycrystalline CuFeO$_2$ target. Amorphous structureof as-deposited film was confirmed by XRD. XPS analysis convinced that the chemical state of Cu$^{+}$ and Fe$^{3+}$ in the film, and the chemical composition of the thin films is close to the stoichiometry of CuFeO$^2$. Surface morphology of the film was analysed by SEM studies. p-type nature and concentration of carriers was investigated by Hall effect measurement. The p–n heterojunction in the structure of Al/n-Si/p-CuFeO$_2$/Al showed good rectifying behaviour with a forward and reverse currents ratio of 555 at 2 V. The turn-on voltage and reverse leakage current values were found to be 0.9 V and 4 $\\mu$A at $−$2 V. Further, the conduction mechanism of forward bias voltage was controlled by thermionic emission (TE) and trap-space charge limited current (TCLC) mechanisms.

  12. Epitaxial Cu(001) films grown on a Cr/Ag/Fe/GaAs(001) buffer system

    International Nuclear Information System (INIS)

    We present a procedure to prepare single-crystalline, high-purity Cu(001) films (templates) suitable as substrates for subsequent epitaxial thin-film growth. The template films were grown in a dedicated molecular-beam epitaxy system on a Cr/Ag/Fe/GaAs(001) buffer layer system. Low-energy electron diffraction and X-ray diffraction were applied to determine the surface orientation and the epitaxial relationship between all layers of the stack. Post-annealing at moderate temperatures enhances the quality of the film as shown by low-energy electron diffraction and atomic force microscopy. X-ray photoemission and Auger electron spectroscopy confirm that no atoms of the buffer layers diffuse into the Cu film during the initial preparation and the post-annealing treatment. The completed Cu(001) template system can be exposed to air and afterwards refurbished by Ar+-ion bombardment and annealing, enabling the transfer between vacuum systems. The procedure provides suitable conductive thin film templates for studies of epitaxial thin films, e.g. on the magnetic and magnetotransport properties of Co and Ni based films and multilayers. - Highlights: • Preparation of epitaxial Cu(001) template films on an insulating substrate • Characterization of template structure, orientation, cleanness, and roughness • Template films can be exposed to air and refurbished in different vacuum system. • Template films are suitable for further thin film growth at up to 570 K

  13. Moessbauer Studies of Nanosize CuFe2O4 Particles

    International Nuclear Information System (INIS)

    Nanocrystalline CuFe2O4 particles are prepared by wet chemical method. The particles of various sizes are obtained by heat treatment in the temperature range 773-1073 K. The room temperature Moessbauer spectrum for all samples shows the presence of both sextet and doublet indicating the presence of superparamagnetic fractions. The isomer shift, quadrupole splitting and hyperfine field values are found to change with particle size. However, these changes in Moessbauer parameters may also be due to the Jahn-Teller effect that essentially arises due to the migration of Cu2+ from tetrahedral sites to octahedral sites resulting in crystal structure change from cubic to tetragonal system. These aspects are studied by using Moessbauer spectroscopy and are correlated to the X-ray diffraction data.

  14. Oxidation of Refractory Benzothiazoles with PMS/CuFe2O4: Kinetics and Transformation Intermediates

    KAUST Repository

    Zhang, Tao

    2016-05-04

    Benzothiazole (BTH) and its derivatives, 2-(methylthio)bezothiazole (MTBT), 2-benzothiazolsulfonate (BTSA) and 2-hydroxybenzothiazole (OHBT), are refractory pollutants ubiquitously existing in urban runoff at relatively high concentrations. Here, we report their oxidation by CuFe2O4-activated peroxomonosulfate (PMS/CuFe2O4), focusing on kinetics and transformation intermediates. These benzothiazoles can be efficiently degraded by this oxidation process which is confirmed to generate mainly sulfate radicals (with negligible hydroxyl-radical formation) under slightly acidic to neutral pH conditions. The molar exposure ratio of sulfate radical to residual PMS (i.e. Rct) of this process is a constant which is related to reaction condition and can be easily determined. Reaction rate constants of these benzothiazoles towards sulfate radical are (3.3 ± 0.3) × 109, (1.4 ± 0.3) × 109, (1.5 ± 0.1) × 109 and (4.7 ± 0.5) × 109 M-1s-1, respectively (pH 7 and 20 oC). Based on Rct and these rate constants, their degradation in the presence of organic matter can be well predicted. A number of transformation products were detected and tentatively identified using triple-quadruple/linear ion trap MS/MS and high-resolution MS. It appears that sulfate radicals attack BTH, MTBT and BTSA on their benzo ring via electron transfer, generating multiple hydroxylated intermediates which are reactive towards common oxidants. For OHBT oxidation, it prefers to break down the thiazole ring. Due to competitions of the transformation intermediates, a minimum PMS/pollutant molar ratio of 10-20 is required for effective degradation. The flexible PMS/CuFe2O4 could be a useful process to remove the benzothiazoles from low DOC waters like urban runoff or polluted groundwater.

  15. Oxidation of Refractory Benzothiazoles with PMS/CuFe2O4: Kinetics and Transformation Intermediates.

    Science.gov (United States)

    Zhang, Tao; Chen, Yin; Leiknes, TorOve

    2016-06-01

    Benzothiazole (BTH) and its derivatives 2-(methylthio)bezothiazole (MTBT), 2-benzothiazolsulfonate (BTSA), and 2-hydroxybenzothiazole (OHBT) are refractory pollutants ubiquitously existing in urban runoff at relatively high concentrations. Here, we report their oxidation by CuFe2O4-activated peroxomonosulfate (PMS/CuFe2O4), focusing on kinetics and transformation intermediates. These benzothiazoles can be efficiently degraded by this oxidation process, which is confirmed to generate mainly sulfate radicals (with negligible hydroxyl-radical formation) under slightly acidic to neutral pH conditions. The molar exposure ratio of sulfate radical to residual PMS (i.e., Rct) for this process is a constant that is related to the reaction condition and can be easily determined. The reaction rate constants of these benzothiazoles toward sulfate radical are (3.3 ± 0.3) × 10(9), (1.4 ± 0.3) × 10(9), (1.5 ± 0.1) × 10(9), and (4.7 ± 0.5) × 10(9) M(-1) s(-1), respectively (pH 7 and 20 °C). On the basis of Rct and these rate constants, their degradation in the presence of organic matter can be well-predicted. A number of transformation products were detected and tentatively identified using triple-quadruple/linear ion trap MS/MS and high-resolution MS. It appears that sulfate radicals attack BTH, MTBT, and BTSA on their benzo ring via electron transfer, generating multiple hydroxylated intermediates that are reactive toward common oxidants. For OHBT oxidation, the thiazole ring is preferentially broken down. Due to competitions of the transformation intermediates, a minimum PMS/pollutant molar ratio of 10-20 is required for effective degradation. The flexible PMS/CuFe2O4 could be a useful process to remove the benzothiazoles from low dissolved organic carbon waters like urban runoff or polluted groundwater. PMID:27144396

  16. The CU ground MAX-DOAS instrument: characterization of RMS noise limitations and first measurements near Pensacola, FL of BrO, IO, and CHOCHO

    Science.gov (United States)

    Coburn, S.; Dix, B.; Sinreich, R.; Volkamer, R.

    2011-11-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer (O4) in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is proportional to the root mean square (RMS) of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS of ∼6 × 10-6 from solar stray light noise tests using high photon count spectra (compatible within a factor of two with photon shot noise). Laboratory tests revealed two critical instrument properties that, in practice, can limit the RMS: (1) detector non-linearity noise, RMSNLin, and (2) temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines) and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (∼10-2) yet - unless actively controlled - is sufficiently large to create RMSNLin of up to 2 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels °C-1 at 334 nm), and temperature variations of 0.1°C can cause RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. With an integration time of 60 s the instrument can reach RMS noise of 3 × 10-5, and typical RMS in field measurements ranged from 6 × 10-5 to 1.4 × 10-4. The CU GMAX-DOAS was set up at a coastal site near Pensacola, Florida, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL), with daytime average tropospheric vertical column densities (average of data above the detection limit), VCDs, of ∼2 × 1013 molec cm-2, 8 × 1012 molec cm-2 and 4 × 1014 molec cm-2, respectively. HCHO and

  17. Study on Electromagnetorheological Fluid Containing CuPc-Fe3O4 Nanoparticles Composite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Electromagnetorheological(EMR) fluids containing CuPc-Fe3O4 nanopareticles composite were prepared and their properties were studied.The results show that Δτ of this kind of EMR fluids increases with the increments of applied electric field, magnetic field and volume fraction of the nanoparticles composite. Δτ has an approximate linear relationship with γ.When an electric and magnetic field are applied simultaneously,the EMR fluids have a synergistic effect. The EMR fluids have a good long-term stability.

  18. Structure of Sm-Co-Cu-Fe-Zr alloys for permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Linetskij, Ya.L.; Savich, A.N.; Knizhnik, E.G.; Menushenkova, N.V.; Polunin, V.V.; Korovyatskaya, M.V. (Moskovskij Inst. Stali i Splavov (USSR))

    1982-02-01

    Structure changes in the 25 Sm - 50 Co - (10-15) Fe - (8-12) Cu - 2 Zr alloys during their processing for the state with high magnetic properties are investigated by means of optical, electron microscopy and X-ray diffraction analysis. Dendrite non-uniformity is removed during the alloy sintering and the Th/sub 2/Zn/sub 17/ type phase turns to be the basic structural constituent. Tempering at 800 deg C results in transformation of solid solution in the result of which canted cellular and banded structures are formed.

  19. Kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with inert gases

    OpenAIRE

    B. Oleksiak; L. Blacha

    2011-01-01

    Discussion of the kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with argon and helium. The values of the mass penetration coefficient for the liquid and solid phase as well as the mass transfer coefficient were calculated for the temperatures of 1 473 K and 1 548 K, and for the gas flow rate of 5,55 • 10-6, 6,94 • 10-6, 8,33 • 10-6 and 9,72 • 10-6 m • s-1.

  20. Possibilities of removing lead from industrial Cu-Pb-Fe alloy with of argon barbortage

    OpenAIRE

    B. Oleksiak

    2009-01-01

    In this article results of research on removal of the lead from industrial Cu-Pb-Fe alloy by means of argon barbotage are presented. The examinations was performed on an industrial alloy from the “Glogow II” Copperworks. As a basic research equipment a pipe resistance furnace enabling heating of a sample up to 1773 K temperature was used. All researches were conducted at 1473 K, 1523 K, 1573 K temperature and with gas flow 5,55×10-6, 6,94×10-6, 8,33×10-6, 9,72×10-6 m3/s.

  1. Removal of lead from the industrial and synthetic Cu-Pb-Fe alloy with argon barbotage

    OpenAIRE

    B. Oleksiak; G. Siwiec

    2012-01-01

    Results of research on removal of lead from synthetic and industrial Cu-Pb-Fe alloy with argon barbotage are presented. For examinations was taken a synthetic alloy and industrial alloy coming “Glogow II” Copperworks. As basic research equipment was used a pipe resistance furnace enabling heating of samples up to 1 473 K. Examinations were made in 2 test series. The 1 series was performed on the synthetic alloy, while in 2 series was used an industrial alloy. All series were conducted at 1 47...

  2. Magnetic response of FeNbCuBSi RQ ribbons to bi-axial strain

    International Nuclear Information System (INIS)

    Nanocrystalline strip samples of the FeNbCuBSi class that are macroscopically heterogeneous due to surface /volume differences have been investigated. This heterogeneity is found to be a general property of the class. It represents a base for mutual force influence between the surface and the majority volume beneath. The bi-axial in-plane stress exerted by the ribbon surfaces on the volume is demonstrated first of all by a magnetoelastic anisotropy. The contribution of the creep-induced anisotropy, which can build up under the surface stress at post-treatment temperature, is also found possible

  3. Permeability spectra of neutron-irradiated and annealed amorphous FeCuNbSiB ribbons

    International Nuclear Information System (INIS)

    The neutron irradiation effects of soft magnetic properties in the as-quenched and the annealed amorphous Fe73.5Cu1Nb3Si13.5B9 alloys were studied by complex permeability spectra measurement. The annealing at 823 K caused the decrease of permeability from irreversible domain wall motion but increase the permeability from reversible magnetization, compared to the as-quenched sample. The neutron irradiation in the as-quenched sample increases the permeability from both irreversible and reversible magnetization processes. The neutron irradiation in the annealed sample showed the increase of permeability from irreversible domain wall motion, but decrease of permeability from reversible magnetization

  4. Thermostability of Al-Cu-Mg-Fe-Ni Alloy with Trace Scandium and Zirconium

    Institute of Scientific and Technical Information of China (English)

    Yu Kun; Li Songrui; Li Wenxian

    2000-01-01

    Three Al-Cu-Mg-Fe-Ni-Sc-Zr ingot metallurgy alloys with different compositions had been prepared. The hardness variations of cold-rolled alloy plates during annealing process had been measured. The tensile properties at both ambient and elevated temperatures were also measured. The microstructures of alloys were observed by using optical microscope and TEM. It was found that the dispersed Al3(Sc, Zr) particles could pin dislocations, stabilize substructures and impede the movement of boundaries. The ambient and elevated temperature properties of alloy with Al3(Sc, Zr) particles were improved. And the tensile strength of alloy did not improve obviously with rich iron and nicker addition.

  5. Kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with inert gases

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2011-04-01

    Full Text Available Discussion of the kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with argon and helium. The values of the mass penetration coefficient for the liquid and solid phase as well as the mass transfer coefficient were calculated for the temperatures of 1 473 K and 1 548 K, and for the gas flow rate of 5,55 • 10-6, 6,94 • 10-6, 8,33 • 10-6 and 9,72 • 10-6 m • s-1.

  6. Cu, Mn, Fe, and Zn Levels in Soils of Shika Area, Nigeria

    Institute of Scientific and Technical Information of China (English)

    S. A. MASHI; S. A. YARO; A. S. HAIBA

    2004-01-01

    Heavy metals presented in toxic amounts can become injurious to human health. In areas where there is a high level of human activities on soils (such as agriculture and grazing) studies are therefore required from time to time to monitor levels of such metals in the soils in order to identify the point in time when toxicity problems become real. The 英文摘要: of this paper is to determine the concentrations of some trace metals (Cu, Mn, Fe, and Zn) in soils under cultivation and grazing practices in Shika, a rural area of Kaduna state of Nigeria. Method In this study, soil samples collected from three different categories of locations (cultivated, grazed, and uncultivated/non- grazed serving as a control) across Shika area, Nigeria, were analysed for some trace metal levels (Cu, Mn, Fe, and Zn) using atomic absorption spectrophotometry. For each category, multiple sites were chosen to accommodate all possible intra-category variations, especially in terms of land use and management history and topographic characteristics. Topsoil (0-15 cm) and subsoil (20-30 cm) samples were collected from every site and analysed for the above metals. Averaged values of the metals for the three categories revealed that Zn is the most abundant metal, followed by Fe, then Mn and Cu the least. Results The results obtained indicate that the cultivation practices, and to a lesser extent grazing, in the area result in higher levels of all the metals than in the control, suggesting that crop immobilization of the metals from soils of the area is low, and that their systematic accumulation is taking place in cultivated soils of the area. Prospects of having elevated soil levels of the metals due to cultivation practices in the area therefore seem quite high. Conclusion On the basis of the results obtained, it was concluded that grazing and cultivation practices have in general caused some significant elevations in the bioavailable (i.e the plant available forms) levels of Zn, Fe, Mn

  7. First-order reversal curve analysis of graded anisotropy FePtCu films

    Science.gov (United States)

    Bonanni, Valentina; Fang, Yeyu; Dumas, Randy K.; Zha, Chaolin; Bonetti, Stefano; Nogués, Josep; Åkerman, Johan

    2010-11-01

    The reversal mechanisms of graded anisotropy FePtCu films have been investigated by alternating gradient magnetometer (AGM) and magneto-optical Kerr effect (MOKE) measurements with first-order reversal curve (FORC) techniques. The AGM-FORC analysis, which clearly shows the presence of soft and hard components, is unable to resolve how these phases are distributed throughout the film thickness. MOKE-FORC measurements, which preferentially probe the surface of the film, reveal that the soft components are indeed located toward the top surface. Combining AGM-FORC with the inherent surface sensitivity of MOKE-FORC analysis allows for a comprehensive analysis of heterogeneous systems such as graded materials.

  8. Microstructure and tensile properties of FeMnNiCuCoSnx high entropy alloys

    International Nuclear Information System (INIS)

    Highlights: ► We develop a new high entropy alloy system. ► The alloys have good plasticity that can do tensile testing at room temperature. ► The maximum tensile strain can reach to 16.9%. -- Abstract: High-entropy FeMnNiCuCoSnx (x denotes the atomic fraction of Sn) alloys with good plasticity have been developed. The systematical investigation demonstrates that the concentration of Sn element plays a significant role in the microstructure and tensile properties. As 0.03 5.6Sn) in the interdendritic regions forms, which degrades the ductility of alloys.

  9. An investigation on microwave sintering of Fe, Fe–Cu and Fe–Cu–C alloys

    Indian Academy of Sciences (India)

    Raja Annamalai; Anish Upadhyaya; Dinesh Agrawal

    2013-06-01

    The powder characteristics of metallic powders play a key role during sintering. Densification and mechanical properties were also influenced by it. The current study examines the effect of heating mode on densification, microstructure, phase compositions and properties of Fe, Fe–2Cu and Fe–2Cu–0.8C systems. The compacts were heated in 2.45 GHz microwave sintering furnaces under forming gas (95%N2–5%H2) at 1120 °C for 60 min. Results of densification, mechanical properties and microstructural development of the microwave-sintered samples were reported and critically analysed in terms of various powder processing steps.

  10. Strength of deformation-processed Cu-Fe in-situ composites

    Institute of Scientific and Technical Information of China (English)

    GE Ji-ping; ZHAO Hong; YAO Zai-qi

    2005-01-01

    The strength of the deformation-processed Cu-Fe in-situ composite was conducted by material test system(MTS). The results show that the strength increases with the increasing deformation strain and iron content,which is greater than that of the calculated value based on the rule of mixture. The mechanism of strengthening was analysed and evidenced by interface barrier. The correlation between the strength and the thickness of copper phase (tcu) obeys Hall-Petch relationship and can be described well by geometrical necessary dislocation model and interface as dislocation source model.

  11. Effect of biquadratic coupling on current induced magnetization switching in Co/Cu/Ni-Fe nanopillar

    Science.gov (United States)

    Aravinthan, D.; Sabareesan, P.; Daniel, M.

    2016-05-01

    The effect of biquadratic coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the free layer magnetization switching dynamics governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The LLGS equation is numerically solved by using Runge-Kutta fourth order procedure for an applied current density of 5 × 1012 Am-2. Presence of biquadratic coupling in the ferromagnetic layers reduces the magnetization switching time of the nanopillar device from 61 ps to 49 ps.

  12. Cu/Fe/Cu叠片轧制工艺及复合强度的研究%Research on Rolling Technologies and Compound Strength of Cu/Fe/Cu Laminated Composite

    Institute of Scientific and Technical Information of China (English)

    柳华炎; 王德志; 杨益航; 梁丹丹

    2011-01-01

    Cu/Fe/Cu composite was produced by cold rolling technology using oxygen copper and electrical pure iron. The effects of rolling reduction and annealing temperature on mechanical properties of composite were analyzed and optical microscopy and scanning electron microscopy (SEM) were utilized to reveal bonding condition. The results show that the optimal comprehensive mechanics performances were obtained under 75% ~ 80% rolling reduction, annealing temperature at700 ℃ for 30 min, and the tensile strength and shear strength reach 385MPa and 358MPa respectively.%采用无氧铜与电工纯铁为原材料运用冷轧复合工艺生产Cu/Fe/Cu复合件,分析了轧制压下率、退火温度对轧合件力学性能的影响,并运用金相显微镜、扫描电镜分析了组元的界面结合情况.结果表明,采用75%、80%压下率的冷轧工艺,且轧后采用700℃×30 min的退火工艺,可获得轧合件最佳的综合力学性能,其抗拉强度达385MPa,抗剪切强度达358MPa.

  13. Macroscopic heterogeneity effects in FeNiNbCuBSi ribbons

    International Nuclear Information System (INIS)

    The effect of Ni substitution on the magnetic response to macroscopic heterogeneity has been investigated on (FeNi)73.5Nb3Cu1B9Si13.5 ribbons. 10, 20 and 30 at% of Ni was alloyed to the detriment of Fe. No significant change was observed as to the bias to build heterogeneity in a non-protective annealing ambience. Instead, the favorable insensitivity of magnetic properties to the heterogeneity, as known for the standard Finemet, gets lost with Ni substitution and serious magnetic hardening takes place for higher Ni percentage. These changes are mainly due to the changed intrinsic properties of the Ni-substituted alloys, as high magnetostriction and the occurrence of a Ni-containing phase, if the alloy is nanocrystallized

  14. Formation dynamics of FeN thin films on Cu(100)

    KAUST Repository

    Heryadi, Dodi

    2012-01-01

    To investigate the structural and magnetic properties of thin films of FeN we have performed ab initio molecular dynamics simulations of their formation on Cu(100) substrates. The iron nitride layers exhibit a p4gm(2 × 2) reconstruction and order ferromagnetically in agreement with experiment. We establish the dynamics and time scale of the film formation as a function of the film thickness. The process is split in two phases: formation of almost flat FeN layers and optimization of the distance to the substrate. Our calculated magnetic moments are 1.67 μ B, 2.14 μ B, and 2.21 μ B for one, two, and three monolayers of iron nitride. © 2011 Elsevier B.V. All rights reserved.

  15. Effect Of Ni-Additions In NANOCRYSTALLIZED FeNiNbCuSiB Alloys

    International Nuclear Information System (INIS)

    Structure and magnetic properties of Fe73.5-xNixNb3Cu1 Si13.5B9 ( x = 0, 5, 10, 15, 20, 25 at.% ) amorphous and nanocrystalline alloys were investigated. For studying the magnetic behaviour upon changes of Ni and Fe concentration X-ray, Moessbauer measurements as well as thermomagnetic analyses were performed. The first crystallization temperature at about 545 deg C was nearly independent on the Ni concentrations. The temperature of the second crystallization stage decreases when Ni content increases. Additions of Ni cause a small change of the Curie temperature. After annealing at 550 deg C for 1 h a nanocrystalline state was formed which leads to magnetic softening of the sample for smaller additions of Ni (x = 0 - 15). The nanocrystalline structure was not observed for higher Ni contents (x = 20, 25).(Authors)

  16. RELATIONSHIP BETWEEN INFRARED RADIATION AND CRYSTAL STRUCTURE IN Fe-Mn-Co-Cu-O SPINELS

    Institute of Scientific and Technical Information of China (English)

    Y. Zhang; D.J. Wen

    2008-01-01

    Ni3+ and Cr3+ doped Fe-Mn-Co-Cu-O spinels have been prepared by solid phase sinfeting. The valence states and distribution of transition ions in the spinel crystals are inferred by the consideration of thermodynamic principle and crystalline field theory. The microstructure and performance of those are studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and IRE-2 infrared radiant instrument. Ni3+ and Cr3+ occupy the vacancies or substitute the other ions in the spinel structures and form diverse spinel structures, which exhibit infrared integral emissivities of 0.93 in the whole band, and 0.94 in the band within 14-25 um too. The content of Fe2O3 and MnO2 in the spinel crystals changes, maybe it induces infrared radiativity of spinels differently.

  17. Electrospun CuFe2O4 nanotubes as anodes for high-performance lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Shengjie Peng; Linlin Li; Madhavi Srinivasan

    2014-01-01

    Herein, we report on the synthesis and lithium storage properties of electrospun one-dimensional (1D) CuFe2O4 nanomaterials. 1D CuFe2O4 nanotubes and nanorods were fabricated by a single spinneret electrospinning method followed by thermal decomposition for removal of polymers from the precursor fibers. The as-prepared CuFe2O4 nanotubes with wall thickness of∼50 nm presented diameters of∼150 nm and lengths up to several millimeters. It was found that phase separation between the electrospun composite materials occured during the electrospinning process, while the as-spun precursor nanofibers composed of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP) and metal salts might possess a core-shell structure (PAN as the core and PVP/metal salts composite as the shell) and then transformed to a hollow structure after calcination. Moreover, as a demonstration of the functional properties of the 1D nanostructure, CuFe2 O4 nanotubes and nanorods were investigated as anodes for lithium ion batteries (LIBs). It was demonstrated that CuFe2O4 nanotubes not only delivered a high reversible capacity of ∼816 mAh·g-1 at a current density of 200 mA·g-1 over 50 cycles, but also showed superior rate capability with respect to counterpart nanorods. Probably, the enhanced electrochemical performance can be attributed to its high specific surface areas as well as the unique hollow structure.

  18. S, Zn, Cr, Cu and Fe changes during fluvial sediments oxidation Transformaciones del S, Zn, Cr, Cu y Fe en sedimentos fluviales durante el proceso de secado

    Directory of Open Access Journals (Sweden)

    María Pía Di Nanno

    2009-12-01

    Full Text Available Acidification of dredged sediments which have been disposed on land is highly dependent on redox shifts. The aim of the present work was to assess changes in sulphur, metal speciation (Zn, Fe, Cr y Cu and acidity caused by a polluted sediment oxidation event. Sediments were dessicated under controlled conditions and sulphide compounds (acid volatile sulphides-AVS- and sulphate, pH and neutralization potential were measured through time during 36 days. Zinc, Cu, Cr and Fe speciation (BCR metal sequential extraction procedure were measured at the beginning of the experiment and at day 22. An acid-base equilibrium method based on the BCR procedure was employed to assess the sediment acidification risk. Some of the re-suspension experiments were inoculated with an Acidithiobacillus ferrooxidans strain to assess biological catalysis on sulphide oxidation. Acid-base equilibrium results indicated the sediment sample had a significant acidification potential. Oxidation increased sulphate levels (56 to 2300 mg S kg-¹ in the desiccation experiment with a temporal evolution adjusted by a logistic model, and a 2100 to 3000 mg SO4 -² L-¹ increase for the resuspension experiments. Sulphide oxidation rates varied between 0 to 3.1.10-9 mg O2 kg-¹ s-¹ for the drying sediment. Zinc changes could be explained partially by ZnS conversion to ZnSO4 during oxidation. Iron reduction could be attributed to an increase in Fe oxides crystallinity. Acid-base equilibrium for the sample indicated it was a potentially acid-generating material. Zinc increased its bioavailability during drying and was the only metal that appeared in significant amounts in solution during re-suspension. Land-filling with dredged sediments could present increased metals bioavailability problems despite having an important and effective neutralization potential.La evaluación de los riesgos de acidificación por deposición de sedimentos dragados en superficie es muy dependiente de los

  19. Identification of Extra-Framework Species on Fe/ZSM-5 and Cu/ZSM-5 Catalysts Typical Microporous Molecular Sieves with Zeolitic Structure

    Directory of Open Access Journals (Sweden)

    E.A. Urquieta-González

    2002-09-01

    Full Text Available Cu and Fe species formed during the preparation of Cu/ and Fe/ZSM-5 catalysts by ion exchange were studied. XRD, SEM, H2-TPR, DRS-UV-VIS, EPR, Mössbauer Spectroscopy (MÖSS and chemical analysis (AAS were used to sample characterization. Cu/ZSM-5 catalysts, irrespective of their Si/Al ratio and Cu content, showed a reduction peak at around 210°C, which was attributed to the reduction of Cu+2 to Cu+1. The reduction peak of Cu+1 to Cu0 shifted to higher temperatures with the increase of Si/Al ratio or with the diminution of Cu/Al ratio, evidencing that isolated Cu cations present a higher interaction with the zeolite structure. The MÖSS data showed the presence of Fe+3 species in charge-compensation sites and a higher content of hematite (Fe2O3 in the catalysts prepared in aqueous medium. The EPR analysis also evidenced the Cu+2 and Fe+3 presence in Cu and Fe/ZSM-5 catalysts, respectively.

  20. Phase selection and nanocrystallization in Cu-free soft magnetic FeSiNbB amorphous alloy upon rapid annealing

    Science.gov (United States)

    Morsdorf, L.; Pradeep, K. G.; Herzer, G.; Kovács, A.; Dunin-Borkowski, R. E.; Povstugar, I.; Konygin, G.; Choi, P.; Raabe, D.

    2016-03-01

    Nucleation of soft magnetic Fe3Si nanocrystals in Cu-free Fe74.5Si15.5Nb3B7 alloy, upon rapid (10 s) and conventional (30 min) annealing, was investigated using x-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy, and atom probe tomography. By employing rapid annealing, preferential nucleation of Fe3Si nanocrystals was achieved, whereas otherwise there is simultaneous nucleation of both Fe3Si and undesired Fe-B compound phases. Analysis revealed that the enhanced Nb diffusivity, achieved during rapid annealing, facilitates homogeneous nucleation of Fe3Si nanocrystals while shifting the secondary Fe-B crystallization to higher temperatures resulting in pure soft magnetic nanocrystallization with very low coercivities of ˜10 A/m.

  1. Deciphering a multistage history affecting U-Cu(-Fe) mineralization in the Singhbhum Shear Zone, eastern India, using pyrite textures and compositions in the Turamdih U-Cu(-Fe) deposit

    Science.gov (United States)

    Pal, Dipak C.; Barton, Mark D.; Sarangi, A. K.

    2009-01-01

    The ˜200-km-long intensely deformed Singhbhum Shear Zone (SSZ) in eastern India hosts India’s largest U and Cu deposits and related Fe mineralization. The SSZ separates an Archaean cratonic nucleus to the south from a Mesoproterozoic fold belt in the North and has a complex geologic history that obscures the origin of the contained iron-oxide-rich mineral deposits. This study investigates aspects of the history of mineralization in the SSZ by utilizing new petrographic and electron microprobe observations of pyrite textures and zoning in the Turamdih U-Cu(-Fe) deposit. Mineralization at Turamdih is hosted in intensively deformed quartz-chlorite schist. Sulfides and oxides include, in inferred order of development: (a) magmatic Fe(-Ti-Cr) oxide and Fe-Cu(-Ni) sulfide minerals inferred to be magmatic (?) in origin; followed by (b) uranium, Fe-oxide, and Fe-Cu(-Co) sulfide minerals that predate most or all ductile deformation, and are inferred to be of hydrothermal origin; and (c) Fe-Cu sulfides that were generated during and postdating ductile deformation. These features are associated with the formation of three compositionally and texturally distinct pyrites. Pyrite (type-A), typically in globular-semiglobular composite inclusions of pyrite plus chalcopyrite in magnetite, is characterized by very high Ni content (up to 30,700 ppm) and low Co to Ni ratios (0.01-0.61). The textural and compositional characteristics of associated chalcopyrite and rare pyrrhotite suggest that this pyrite could be linked to the magmatic event via selective replacement of magmatic pyrrhotite. Alternatively, this pyrite and associated sulfide inclusions might be cogenetic with hydrothermal Fe-oxide. Type-B pyrite that forms elongate grains and irregular relics and cores of pyrite with high Co contents (up to 23,630 ppm) and high Co to Ni ratios (7.2-140.9) are interpreted to be related to hydrothermal mineralization predating ductile deformation. A third generation of pyrite (type C

  2. Low-temperature heat capacity and entropy of chalcopyrite (CuFeS2): estimates of the standard molar enthalpy and Gibbs free energy of formation of chalcopyrite and bornite (Cu5FeS4)

    Science.gov (United States)

    Robie, R.A.; Wiggins, L.B.; Barton, P.B., Jr.; Hemingway, B.S.

    1985-01-01

    The heat capacity of CuFeS2 (chalcopyrite) was measured between 6.3 and 303.5 K. At 298.15 K, Cp,mo and Smo(T) are (95.67??0.14) J??K-1??mol-1 and (124.9??0.2) J??K-1??mol-1, respectively. From a consideration of the results of two sets of equilibrium measurements we conclude that ??fHmo(CuFeS2, cr, 298.15 K) = -(193.6??1.6) kJ??mol-1 and that the recent bomb-calorimetric determination by Johnson and Steele (J. Chem. Thermodynamics 1981, 13, 991) is in error. The standard molar Gibbs free energy of formation of bornite (Cu5FeS4) is -(444.9??2.1) kJ??mol-1 at 748 K. ?? 1985.

  3. Simultanous removal of VOCs and Nox by oxides of Mg, Cu, Al, and Fe, derivatives of hydrotalicites compounds

    International Nuclear Information System (INIS)

    A series of Mg(Cu)-AlFe mixed oxides derived from Hydrotalcites-Like compounds has been prepared. These solids were characterized by various physico-chemical methods and their catalytic performances were tested towards the catalytic oxidation of propene and the simultaneous elimination of propene and NOx. X-Ray Diffraction of the calcined samples, revealed the existence of oxide and spinel phases such as MgO, CuO,-Fe2O3 and/or Fe3O4, MgFe2O4or CuFe2O4. Moreover, the temperature programmed reduction showed that copper and iron oxide species are easily reducible. The catalytic performances of the catalysts towards propene oxidation showed a better activity for Cu2Mg2Fe2500 due to a better dispersion of copper species in this solid. On the other hand, samples with low copper and iron contents presented a better activity towards the simultaneous elimination of propene and NO. (author)

  4. Spray pyrolytically deposited Fe-doped Cu2O thin films for solar hydrogen generation: Experiments & first-principles analysis

    International Nuclear Information System (INIS)

    We present here a combined study on photocatalysis by Fe-doped Cu2O thin films using first-principles density functional theory (DFT) based calculations and experiments. The results of DFT calculations show that the top of the valence band and bottom of the conduction band of undoped Cu2O lies at the Γ point of Brillouin zone, suggesting that pure Cu2O a direct band gap material. However, there is an appearance of a sharp peak at the fermi energy level in the total density of states of Fe-doped Cu2O that essentially comes from Fe 3d states, keeping it still a direct band gap material. To validate the theoretical results, experiments were carried out by preparing thin films of Cu2O doped with 0, 1.0, 2.0, 3.0 & 5.0 atom % Fe via spray pyrolysis method and characterized with X-Ray Diffractometry (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM), UV–Vis Spectroscopy and Photoelectrochemical measurements. The results exhibited that 2 atom % Fe-doped Cu2O sample produces significant photocurrent of 1.86 mAcm−2 at 0.8 V/SCE as compared to undoped Cu2O samples of 0.62 mAcm2 at 0.8 V/SCE with an experimental band-gap value of 2.21 and 2.50 eV respectively. The observed change in the experimental band gap and that estimated by first-principles calculations compare well, thus suggesting that such calculations have the potential to be used in screening various dopants before performing the experiments thereby saving precious chemicals, time and energy. - Highlights: • Cu2O thin films have been successfully prepared using spray pyrolysis method. • DFT calculations show an appearance of sharp peak at fermi level in Fe-doped Cu2O. • Our theoretical & experimental results complimented each other. • Maximum value of IPCE of 6.0% was obtained for 2 atom % Fe-doped sample at 450 nm

  5. Energy Parameters of Interfacial Layers in Composite Systems: Graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and Semiconductor (Si,Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb

    Directory of Open Access Journals (Sweden)

    B.P. Koman

    2015-12-01

    Full Text Available On the basis of the non-equilibrium thermodynamics relations and the surface physics phenomena we calculate adhesion and energy parameters to characterize the interfacial interactions in graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and semiconductor (Si, Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb systems. We analyze trends of the interfacial energy, interfacial tension, work of adhesion and the energy of adhesive bonds on the contacting element’s atomic number in the periodic table and on the electronegativity difference of interacting elements. Thus, this work provides theoretical basis for the development of new composite materials.

  6. FeMnCuO4复合氧化物的光热转换%SOLAR THERMAL CONVERSION OF FeMnCuO4 COMPOUND OXIDE

    Institute of Scientific and Technical Information of China (English)

    王华林; 余锡宾

    1999-01-01

    选用铁、锰、铜的硝酸盐,以共沉淀法合成了尖晶石结构的FeMnCuO4复合氧化物,并对其结构进行表征.研究了温度、溶液pH值等因素对FeMnCuO4复合氧化物的产率、粒径及光学性能的影响.

  7. 高质量尺寸可调CuFeS2纳米晶的合成与光电性质%Synthesis and Photoelectric Properties of High Quality CuFeS2 Nanocrystals with Tunable Sizes

    Institute of Scientific and Technical Information of China (English)

    张卓磊; 李冬泽; 刘志辉; 解仁国

    2014-01-01

    制备了单分散性良好且尺寸可调的具有荧光性质的CuFeS2纳米晶,利用紫外-可见吸收光谱( UV-Vis)、荧光光谱、透射电子显微镜( TEM)、X射线粉末衍射( XRD)、元素分析和光电流测试等技术对其组分和结构进行了表征,分析了CuFeS2纳米晶尺寸变化对吸收光谱和光电响应行为的影响规律。随着CuFeS2纳米晶尺寸增大,其吸收峰位表现出符合量子尺寸效应的相应红移;具有荧光性质的CuFeS2纳米晶可控制备预示其在生物医学成像和光电器件等领域具有应用前景。%The mono-dispersed CuFeS2 nanocrystals( NCs) with tunable sizes were synthesized and characte-rized by UV-Vis-NIR absorption spectroscopy, transmission electron microscopy( TEM) , X-ray powder diffrac-tion( XRD) and inductively coupled plasma( ICP) . It is found that the as-prepared CuFeS2 NCs show photolu-minescence in visible region. The photo-responsive properties of CuFeS2 NCs further reveal their suitability as optically active components for optoelectronic devices and the growth in size due to the quantum size effect. All the experimental results indicate that as-prepared CuFeS2 NCs with characteristics of fluorescence has potential application in biomedical imaging and optoelectronic devices.

  8. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    Science.gov (United States)

    Mao, J.; Fan, S.; Jacob, D. J.; Travis, K. R.

    2013-01-01

    The hydroperoxyl radical (HO2) is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions Cu(I)/Cu(II) and Fe(II)/Fe(III) to rapidly convert HO2 to H2O in aqueous aerosols. The implied HO2 uptake and conversion to H2O significantly affects global model predictions of tropospheric OH, ozone, carbon monoxide (CO) and other species, improving comparisons to observations in the GEOS-Chem model. It represents a previously unrecognized positive radiative forcing of aerosols through the effects on the chemical budgets of major greenhouse gases including methane and hydrofluorocarbons (HFCs).

  9. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    Directory of Open Access Journals (Sweden)

    J. Mao

    2012-10-01

    Full Text Available The hydroperoxyl radical (HO2 is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involve conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions (TMI Cu(I/Cu(II and Fe(II/Fe(III to rapidly convert HO2 to H2O in aerosols. The implied HO2 uptake significantly affects global model predictions of tropospheric OH, ozone, and other species, improving comparisons to observations, and may have a major and previously unrecognized impact on atmospheric oxidant chemistry.

  10. DETERMINATION OF Cu, Fe, Mn, Zn AND FREE FATTY ACIDS IN PEQUI OIL

    Directory of Open Access Journals (Sweden)

    Aparecida M. S. Mimura

    2016-06-01

    Full Text Available Pequi (Caryocar brasiliense Camb., a typical fruit of the Brazilian Cerrado, is an important source of micronutrients and fatty acids. In this work, a new approach for the acid digestion (using H2SO4, HNO3 and H2O2 of pequi oil samples and the determination of Cu, Fe, Zn and Mn by flame atomic absorption spectrometry (F AAS was employed. Capillary zone electrophoresis (CZE was used for free fatty acid (FFA determination after simple and fast extraction with heated ethanol. Good results regarding precision (RSD < 10%, in most cases, sensitivity and adequate LOD and LOQ values were obtained. The accuracy was evaluated using spike tests and the recoveries were from 97 to 107%. The analytes were investigated in four different pequi oil samples. Fe was the trace element with the highest concentration (from 1.99 to 10.3 mg/100 g, followed by Zn, Mn and Cu (1.15 to 3.19, 0.42 to 0.91 and 0.31 to 0.56 mg/100 g, respectively. The main FFA found were oleic acid and palmitic acid (1.61 to 10.7 and 0.82 to 2.69 g/100 g, respectively, while linoleic acid (0.50 g/100 g was detected in only one sample. The pequi oil chemical composition showed good characteristics to be used as a food additive, in cosmetic formulations and for traditional medicine.

  11. Thermodynamics of Fe Cu alloys as described by a classic potential

    Science.gov (United States)

    Caro, A.; Caro, M.; Lopasso, E. M.; Turchi, P. E. A.; Farkas, D.

    2006-03-01

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. [M. Ludwig, D. Farkas, D. Pedraza, S. Schmauder, Model. Simul. Mater. Sci. Eng. 6 (1998) 19]. In this work we extract thermodynamic information from this interatomic potential. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials. Improved potentials, primarily for the pure components, should be developed to account for proper phase stability in the solid phase up to melting. Finally we suggest an approach to improve existing potentials for this system.

  12. Thermodynamics of Fe-Cu alloys as described by a classic potential

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States)]. E-mail: caro2@llnl.gov; Caro, M. [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Lopasso, E.M. [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Turchi, P.E.A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Farkas, D. [Department of Materials Science and Engineering, Virginia Tech., Blacksburg, VA 24061 (United States)

    2006-03-01

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. [M. Ludwig, D. Farkas, D. Pedraza, S. Schmauder, Model. Simul. Mater. Sci. Eng. 6 (1998) 19]. In this work we extract thermodynamic information from this interatomic potential. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials. Improved potentials, primarily for the pure components, should be developed to account for proper phase stability in the solid phase up to melting. Finally we suggest an approach to improve existing potentials for this system.

  13. Impact of biogenic nanoscale metals Fe, Cu, Zn and Se on reproductive LV chickens

    Science.gov (United States)

    Khiem Nguyen, Quy; Dieu Nguyen, Duy; Kien Nguyen, Van; Thinh Nguyen, Khac; Chau Nguyen, Hoai; Tin Tran, Xuan; Nguyen, Huu Cuong; Tien Phung, Duc

    2015-09-01

    Using biogenic nanoscale metals (Fe, Cu, ZnO, Se) to supplement into diet premix of reproductive LV (a Vietnamese Luong Phuong chicken breed) chickens resulted in certain improvement of poultry farming. The experimental data obtained showed that the farming indices depend mainly on the quantity of nanocrystalline metals which replaced the inorganic mineral component in the feed premix. All four experimental groups with different quantities of the replacement nano component grew and developed normally with livability reaching 91 to 94%, hen’s bodyweight at 38 weeks of age and egg weight ranged from 2.53-2.60 kg/hen and 50.86-51.55 g/egg, respectively. All these farming indices together with laying rate, egg productivity and chick hatchability peaked at group 5 with 25% of nanoscale metals compared to the standard inorganic mineral supplement, while feed consumption was lowest. The results also confirmed that nanocrystalline metals Fe, Cu, ZnO and Se supplemented to chicken feed were able to decrease inorganic minerals in the diet premixes at least four times, allowing animals to more effectively absorb feed minerals, consequently decreasing environmental pollution risks.

  14. REE and Trace Element Geochemistry of Yinachang Fe-Cu-REE Deposit, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    杨耀民; 涂光炽; 胡瑞忠

    2004-01-01

    REE and other trace elements in ores, wall rocks, alkaline volcanic rocks and diabase dikes have been determined in the Yinachang Fe-Cu-REE deposit. Comparative studies of REE and trace element geochemical characteristics of these geological bodies indicate that the ores and alkaline volcanic rocks contain abundant REE and Y (65.9-4633)×10-6, with higher abundances of As, Mo, Nb, Co and U than those of the crust. Their chondrite-normalized patterns show a strong enrichment of LREE and a positive Eu anomaly, in contrast to those of the dolomites which are characterized by slight LREE enrichment and moderate negative Eu anomaly. The REE patterns of ores are similar to those of hydrothermal sediment cores in the East Pacific Rise, whereas the REE patterns of dolomites are similar to those of PAAS (Post-Archean Average Shale). In combination with the geological setting of the deposit, the primary ore-forming fluids might have higher REE and volatile elements, and might have been derived from mantle degassing, or the alkaline volcanic magmas. The Yinachang Fe-Cu-REE ore deposit is considered to be of volcanic exhalation-hydrothermal sedimentary origin.

  15. Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tanhong Cai

    2002-12-31

    Three papers are included in this dissertation. The first paper: ''Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED studies'', is in press with ''Surface Science''. The second paper: ''An STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface'' is submitted to ''Physical Review B, Rapid Communication''. The third paper: ''Pseudomorphic starfish: arrangement of extrinsic metal atoms on a quasicrystalline substrate'' is submitted to ''Nature''. Following the third paper are general conclusions and appendices that document the published paper ''Structural aspects of the three-fold surface of icosahedral Al-Pd-Mn'' (appearing in volume 461, issue 1-3 of ''Surface Science'' on page L521-L527, 2000), the design as well as the specifications of the aluminum evaporator used in the aluminum deposition study in this dissertation, an extended discussion of the aluminum deposition on the quasicrystalline surface, and the STM database.

  16. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calo-rimeter over a wide temperature range from 1482 to 1818 K.A maximum under-cooling of 221 K(0.13 Tm)was achieved and the specific heat was determined as 44.71 J·mol1·K1.The excess specific heat,enthalpy change,entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results.It was found that the calculated results by traditional esti-mating methods can only describe the solidification process under low under-cooling conditions.Only the experimental results can reflect the reality under high undercooling conditions.Meanwhile,the thermal diffusivity,thermal conductivity,and sound speed were derived from the present experimental results.Furthermore,the solidified microstructural morphology was examined,which consists of(Fe)and(Cu)phases.The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  17. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    WANG HaiPeng; LUO BingChi; CHANG Jian; WEI BingBo

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calorimeter over a wide temperature range from 1482 to 1818 K. A maximum undercooling of 221 K (0.13 Tm) was achieved and the specific heat was determined as 44.71 J·mol-1·K-1. The excess specific heat, enthalpy change, entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results. It was found that the calculated results by traditional estimating methods can only describe the solidification process under low undercooling conditions. Only the experimental results can reflect the reality under high undercooling conditions. Meanwhile, the thermal diffusivity, thermal conductivity, and sound speed were derived from the present experimental results. Furthermore, the solidified microstructural morphology was examined, which consists of (Fe) and (Cu) phases. The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  18. Crystallization and Hardness of Melt Spun Fe73Si13B9Nb4Cu1 Alloy

    Institute of Scientific and Technical Information of China (English)

    J.I.Akhter; M.Iqbal; M.Siddique; M.Abmad; M.A.Haq; M.A.Shaikh; Z.Q.Hu

    2009-01-01

    An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe (bcc) and Fe3Si phases. In the second stage, Fe2B and α-Fe (Si,Nb) phases were produced. Mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe (Si,Nb) phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.

  19. X?-DVM modelling of oxygen transport in YBa2Cu3O7-? and SrFeO3

    Science.gov (United States)

    Yuryeva, Elmira I.

    The reasons for oxygen transport in YBa2Cu3O7-? and SrFeO3 were investigated, using the X?-discrete variation method. Reduced binding energy and other parameters of the electronic energy structure were calculated for a number of crystal fragments within the T and O phases of YBa2Cu3O7-? and the cubic phase of SrFeO3. The following results were obtained: (i) test calculations of reduced binding energy confirmed that high temperature should be a condition of existence of the T phase, as compared with the O phase of YBa2Cu3O7-?; (ii) an increase in temperature up to ?400°C points to the beginning of the Jahn-Teller dynamic effect in SrFeO3; and (iii) transport of neutral and charged oxygen atoms results in distributions of stable and unstable oxygen vacancies, respectively.

  20. Structural and magnetic properties of epitaxial delafossite CuFeO{sub 2} thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Toyanath; Senty, Tess R.; Trappen, Robbyn; Zhou, Jinling; Borisov, Pavel; Holcomb, Mikel B.; Bristow, Alan D.; Lederman, David [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Chen, Song; Song, Xueyan [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6070 (United States); Ferrari, Piero; Cabrera, Alejandro L. [Pontificia Universidad Catolica, Instituto de Física, Santiago (Chile)

    2015-01-07

    Growth of pure phase delafossite CuFeO{sub 2} thin films on Al{sub 2}O{sub 3} (00.1) substrates by pulsed laser deposition was systematically investigated as a function of growth temperature and oxygen pressure. X-ray diffraction, transmission electron microscopy, Raman scattering, and x-ray absorption spectroscopy confirmed the existence of the delafossite phase. Infrared reflectivity spectra determined a band edge at 1.15 eV, in agreement with the bulk delafossite data. Magnetization measurements on CuFeO{sub 2} films demonstrated a phase transition at T{sub C} ≈ 15 ± 1 K, which agrees with the first antiferromagnetic transition at 14 K in the bulk CuFeO{sub 2}. Low temperature magnetic phase is best described by commensurate, weak ferromagnetic spin ordering along the c-axis.

  1. Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu4FeAlCO3

    Institute of Scientific and Technical Information of China (English)

    CHEN; Chunxia; XU; Chenghua; FENG; Liangrong; SUO; Jishua

    2005-01-01

    The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hydroxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is proposed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

  2. Study of structural and magnetic properties of (Co–Cu)Fe{sub 2}O{sub 4}/PANI composites

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, Mohd., E-mail: md.hashim09@gmail.com [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Alimuddin [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Shirsath, Sagar E. [Spin Device Technology Centre, Department of Information Engineering, Shinshu University, Nagano 380-8553 (Japan); Meena, S.S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kotnala, R.K. [National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110 012 (India); Kumar, Shalendra [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Bhatt, Pramod [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Jotania, R.B. [Department of Physics, School of Science, Gujarat University, Ahmedabad 380 009 (India); Kumar, Ravi [Centre for Material Science Engineering, National Institute of Technology, Hamirpur 171 005, HP (India)

    2013-08-15

    The nanocomposites of the polyaniline and Co{sub 1−x}Cu{sub x}Fe{sub 2}O{sub 4} (PANI/CoCuFe) were prepared by in-situ oxidative polymerization of aniline. Prepared nanocomposites samples were characterized by using various experimental techniques like X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), Mössbauer spectroscopy and ultraviolet–visible spectrophotometry (UV–VIS). The elemental analysis as obtained from the energy dispersive X-ray spectroscopy (EDAX) measurement is in close agreement with the expected composition from the stoichiometry of the reactant solutions. XRD result confirms that all the samples have the single phase cubic spinel structure. Unit cell parameter ‘a’ is found to decrease with the increase in copper ion substitution. The crystallite size was investigated by using the Debye–Scherer formula and it was found in the range of ∼28–37 nm. FE-SEM confirmed the homogeneous and well defined surface morphology of the synthesized samples. FT-IR study showed the main absorption bands corresponding to the spinel structure those arose due to the tetrahedral and octahedral stretching vibrations. Cation distribution was estimated using XRD data. Hysteresis measurements revealed that the saturation magnetization decreased with increase in Cu{sup 2+} substitution. Magnetic environment of {sup 57}Fe in Cu-doped cobalt ferrite was investigated by using Mössbauer spectroscopy. Mössbauer study evidenced the ferrimagnetic behavior of the synthesized samples. - Highlights: • Crystallite size decreases with increasing Cu{sup 2+} substitution. • The prepared samples show the formation of single phase cubic spinel structure. • Cation distribution shows that Cu and Co ions shows strong preference toward octahedral B site. • Magnetization decreases with increasing Cu{sup 2+} substitution. • Mössbauer study shows

  3. Crystal structure of CuFeInSe{sub 3} from X-ray powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Asiloe J.; Delgado, Gerzon E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, Pedro [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2007-02-15

    The crystal structure of the adamantane compound CuFeInSe{sub 3}, belonging to the system (CuInSe{sub 2}){sub 1-x}(FeSe){sub x} with x=0.5, was analyzed using X-ray powder diffraction data. Several model structures were derived from the structure of the selenium rich phase CuInSe{sub 2.3} by permuting the cations in the available Wyckoff positions. The refinement of the best model by the Rietveld method in the tetragonal space group P anti 42c (N 112), Z=1, with unit cell parameters a=5.7762(2) Aa, c=11.5982(7) Aa and V=386.97(3) Aa{sup 3} led to R{sub p}=8.0%, R{sub wp}=9.6%, R{sub exp}=6.2% and {chi}{sup 2}=1.7 for 134 independent reflections. The model that best fitted the diffraction data has the following atomic distribution: Cu in Wyckoff site 2f; Fe in Wyckoff site 2d; In in Wyckoff site 2b and 1/3Cu, 1/3Fe, 1/3In in Wyckoff site 2f; Se in Wyckoff site 8n. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Research on magnetic performance of Nd13Fe80.1-xTixB6.5Zr0.1Cu0.3 permanent magnetic alloy%Nd13Fe80.1-xTixB6.5Zr0.1Cu0.3永磁合金磁性能研究

    Institute of Scientific and Technical Information of China (English)

    尤俊华; 连法增; 赵康军; 王继杰; 裴文利; 李庆达

    2008-01-01

    HDDR(氢化-歧化-脱氢-再结合)工艺是制备各向异性Nd2Fe14B基磁粉的有效方法.主要研究了改进的d-HDDR工艺及添加合金元素Ti对Nd13Fe80.1-xTixB6.5Zr0.1Cu0.3(x=0、1.0、2.0)合金磁性能的影响规律.结果表明,d-HDDR工艺中吸氢氢压和歧化时间是促使材料产生磁各向异性的#合金经d-HDDR工艺处理,其最佳磁性能为:Br=1.39T;iHc=1006kA/m;(BH)max=169.66kJ/m3;DOA=0.797.关键;合金元素Ti使NdFeB合金矫顽力显著提高,其作用主要体现在两方面:一方面是在晶界间形成低熔物,抑制晶粒长大、细化晶粒,改善富Nd相的组织结构,使富Nd相沿边界更加均匀地分布;另外,Ti元素使Nd2Fe14B晶界平直而清晰,主相晶粒表面各向异性提高,反磁化畴难以形核,从而使矫顽力提高,其最佳添加量为1.0%(原子分数).成分为Nd13Fe79.1Ti1.0B6.5Zr0.1Cu0.3 的2#合金经d-HDDR工艺处理,其最佳磁性能为:"Br=1.39T;iHc=1006kA/m;(BH)max=169.66kJ/m3;DOA=0.797.

  5. Heterogeneous UV/Fenton catalytic degradation of wastewater containing phenol with Fe-Cu-Mn-Y catalyst

    Institute of Scientific and Technical Information of China (English)

    郑展望; 雷乐成; 徐生娟; 岑沛霖

    2004-01-01

    The heterogeneous UV/Fenton process with the appropriate amount of Fe-Mn-Cu-Y as catalyst was developed and various operation conditions for the degradation of phenol were evaluated. The results indicated that by using the heterogeneous UV/Fenton process, the CODcr removal rate reached almost 100% for wastewater containing phenol. Compared with the homogeneous process, the developed catalyst could be used at wider pH range in the UV/Fenton process. Comparison of various heterogeneous process showed that heterogeneous UV/Fenton process was best. The heterogeneous UV/Fenton process with Fe-Mn-Cu-Y catalyst is highly efficient in degrading various organic pollutants.

  6. Bleaching effect and nonvola-tile holographic storage in doubly doped LiNbO3:Fe:Cu crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The bleaching effect, i. e. the crystal shows that decoloration after it is illuminated by ultraviolet light, has been observed in congruent LiNbO3:Fe :Cu crystals. Based on this bleaching effect, a new technique including the reco rding phase by two interfering red beams and fixing phase by both UV light and a coherent red beam has been experimentally investigated to realize nonvolatile holographic storage in LiNbO3:Fe:Cu. The results of proof-of-concept experiments confirm that bleaching effect becomes an alternative physical mechanism for nonv olatile holographic storage with high recording sensitivity and weak light-induced scattering noise.

  7. Elastic properties of fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys from first-principles calculations

    OpenAIRE

    Reeh, S; Music, D; Ekholm, Marcus; Abrikosov, Igor; Schneider, J. M.

    2013-01-01

    The influence of the valence electron concentration of X in fcc Fe-Mn-X (X=Cr, Co, Ni, Cu) alloys on the elastic and magnetic properties has been studied by means of ab initio calculations for alloy element concentrations of up to 8 at. % X. We observe that Cu increases the bulk-to-shear modulus (B/G) ratio by 19.2%. Simultaneously magnetic moments of Fe and Mn increase strongly. The other alloying elements induce less significant changes in B/G. The trends in B/G may be understood by conside...

  8. Catalytic Synthesis of α-Aminonitriles Using Nano Copper Ferrite CuFe2O4 under Green Conditions

    OpenAIRE

    Ali Gharib; Nader Noroozi Pesyan; Leila Vojdani Fard; Mina Roshani

    2014-01-01

    Copper ferrite nanomaterial CuFe2O4 as reusable heterogeneous initiator in the synthesis of α-aminonitriles. The nanocatalyst is easily recovered and its reusability is recorded. Synthesis of α-aminonitriles derivatives by one-pot reaction of different aldehydes with amines and trimethylsilyl cyanides has been developed using nano copper ferrite CuFe2O4 catalyst under room temperature and green solvent (water as solvent) conditions. α-aminonitriles are important in preparing a wide variety of...

  9. Identical spin fluctuations in Cu- and Co-doped BaFe2As2 independent of electron doping

    Science.gov (United States)

    Grafe, H.-J.; Gräfe, U.; Dioguardi, A. P.; Curro, N. J.; Aswartham, S.; Wurmehl, S.; Büchner, B.

    2014-09-01

    We present As75 nuclear magnetic resonance measurements on single crystals of BaFe2As2, BaFe1.8Co0.2As2, and BaFe1.82Cu0.18As2. While only Co doping induces bulk superconductivity on a broad doping range, the spin fluctuations probed by the nuclear spin-lattice relaxation rate (T1T )-1 are identical for both dopings down to Tc. Below this temperature, (T1T)-1 of the Cu-doped sample continues to rise, proving that (a) there is a quantum critical point below the superconducting dome, and (b) adding electrons does not affect the spin fluctuations. Consequently, we analyze the Knight shift data in terms of a two-component scenario, with one hyperfine coupling to an itinerant degree of freedom and the other to Fe moments.

  10. Effect of substitutions on 3d magnetism in Gd2Fe14-xMxC compounds, with M=Ni, Si, Cu or V

    International Nuclear Information System (INIS)

    Results of magnetic measurements and 57Fe Moessbauer spectroscopy performed on Gd2Fe14-xMxC compounds, with M=Ni, Si, Cu or V are presented. As M is substituted for Fe, the six crystallographically inequivalent iron sites split into seven inequivalent sites for M=Si, Cu, V, or eight for M=Ni. The analysis of the hyperfine fields and relative intensities supports a preferential distribution of the substitutional elements on the Fe lattice sites. The effects of the substitutional elements on Curie temperatures and anisotropy fields as well as on Fe hyperfine parameters are discussed on the grounds of the preferential Fe site occupancy. (orig.)

  11. Microstructural study of nanocrystalline Fe-(Cu-Nb)-Si-B ribbons obtained by a nitriding thermochemical treatment

    International Nuclear Information System (INIS)

    The crystallization process of amorphous Fe74Si14B12, Fe73.5Cu1Si13.5B12, Fe74Nb3Si14B9 and Fe73.5Cu1Nb3Si13.5B9 ribbons was investigated by annealing the ribbons under vacuum at 520 deg. C for 6 h. Only Nb containing samples show a nanocrystalline state consisting of α-Fe(Si) nanograins embedded in a remaining amorphous phase. The amorphous ribbons were then submitted to a nitriding thermochemical treatment at 520 deg. C for 6 and 18 h under ammonia. It is observed that crystallization occurs prior to nitrogenation. Upon nitrogenation, a reactive diffusion process of nitrogen is observed, which appears to be slower in the partially crystallized ribbons, due to the presence of a remaining amorphous phase. In the crystalline regions, the α-Fe(Si) phase is disproportionated into α-Fe and probably Si-N precipitates. Then Fe4N is formed when nitrogenation proceeds further

  12. Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco Concentrations of Fe, Mn, Zn, Cu, Ni and Co in benchmark soils of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Caroline Miranda Biondi

    2011-06-01

    Full Text Available Metais pesados formam um grupo de elementos com particularidades relevantes e de ocorrência natural no ambiente, como elementos acessórios na constituição de rochas. Esses elementos, apesar de associados à toxidez, exigem tratamento diferenciado em relação aos xenobióticos, uma vez que diversos metais possuem essencialidade (Fe, Mn, Cu, Zn e Ni e benefício (Co comprovados para as plantas. Nesse contexto, o objetivo deste trabalho foi determinar os teores naturais dos metais Fe, Mn, Zn, Ni, Cu e Co nos solos de referência de Pernambuco. Foram coletadas amostras de solo nas três regiões fisiográficas (Zona da Mata, Agreste e Sertão, dos dois primeiros horizontes dos 35 solos de referência do Estado de Pernambuco. A digestão das amostras baseou-se no método 3051A (USEPA, 1998, e a determinação foi efetuada em ICP-OES. Correlações significativas foram estabelecidas entre os metais e entre estes e a fração argila do solo, em ambos os horizontes, indicando a associação comum da maioria dos metais com solos mais argilosos. A maioria dos solos apresentou teores de Fe, Mn, Zn, Cu, Ni e Co menores que os de solos de outras regiões do País, com litologia mais máfica, o que corrobora o fato de que os teores desses elementos são mais diretamente relacionados aos minerais Fe-magnesianos. Os resultados indicam baixo potencial dos solos de Pernambuco em liberar Cu, Co e Ni para plantas, enquanto deficiências de Zn, Fe e Mn são menos prováveis. Os teores naturais de Fe, Mn, Zn, Cu, Ni e Co determinados podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.Heavy metals are a group of elements with specific features and natural occurrence in the environment, representing an accessory in the formation of rocks. These elements, although associated with toxicity, must be treated different from xenobiotics, since many

  13. Synthesis of Cu-Fe{sub 3}O{sub 4}@graphene composite: A magnetically separable and efficient catalyst for the reduction of 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ran [Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China); Bi, Huiping, E-mail: hpbi@njust.edu.cn [Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); He, Guangyu [Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China); Zhu, Junwu [Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen, Haiqun, E-mail: hqchenyf@hotmail.com [Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Changzhou, Jiangsu Province 213164 (China)

    2014-09-15

    Highlights: • The Cu-Fe{sub 3}O{sub 4}@GE composite was prepared by one-step solvent–thermal method. • The Cu-Fe{sub 3}O{sub 4}@GE composite exhibited the highest catalytic activity with excellent stability. • The Cu-Fe{sub 3}O{sub 4}@GE composite was magnetically separable. - Abstract: In this work, the Cu-Fe{sub 3}O{sub 4}@GE composite was prepared easily by a one-step solvent–thermal method, which achieved the formation of Cu nanoparticles (Cu NPs), Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) and reduction of GO simultaneously. The morphology and structure of the composite was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM). The time-dependent adsorption spectra of the reaction mixture was measured by UV–vis absorption spectroscopy. The results demonstrated that the Cu NPs and Fe{sub 3}O{sub 4} NPs were densely and evenly deposited on the graphene (GE) sheets. It was found that the Cu-Fe{sub 3}O{sub 4}@GE composite exhibited high catalytic activities on the reduction of p-nitrophenol to p-aminophenol. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability.

  14. Characterization of products emanating from conventional and microwave energy roasting of chalcopyrite (CuFeS{sub 2}) concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Mulaba-Bafubiandi, Antoine F., E-mail: Mulaba@twr.ac.za [University of Johannesburg, Extraction Metallurgy Department, Faculty of Engineering and the Built Environment (South Africa)

    2006-02-15

    Chalcopyrite concentrate (83% CuFeS{sub 2}, 3% FeS{sub 2} and 14% ZnS) which is a typical feed to the matte smelting process for copper extraction via pyro metallurgical route has been roasted with microwaves. Comparison of mineralogical phases obtained was made with the case of conventional roasting. Resulting calcines were characterised with Moessbauer spectroscopy and XRD. It was observed that complete oxidation (dead roasting) of the chalcopyrite was achieved after 10 min with microwaves while 20 min were required in the conventional route. The mineralogical phases found in the dead-roasted calcines produced from microwave roasting of this chalcopyrite concentrate were the hematite (Fe{sub 2}O{sub 3}), franklinite (ZnFe{sub 2}O{sub 4}), copper-rich ferrite (Cu{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4}, x {<=} 0.5), and copper ferrite (CuFe{sub 2}O{sub 4}). The findings of this work indicated that it was technologically feasible to oxidize the chalcopyrite with microwaves using a 2.45 GHz multimode applicator.

  15. Characterization of products emanating from conventional and microwave energy roasting of chalcopyrite (CuFeS2) concentrate

    International Nuclear Information System (INIS)

    Chalcopyrite concentrate (83% CuFeS2, 3% FeS2 and 14% ZnS) which is a typical feed to the matte smelting process for copper extraction via pyro metallurgical route has been roasted with microwaves. Comparison of mineralogical phases obtained was made with the case of conventional roasting. Resulting calcines were characterised with Moessbauer spectroscopy and XRD. It was observed that complete oxidation (dead roasting) of the chalcopyrite was achieved after 10 min with microwaves while 20 min were required in the conventional route. The mineralogical phases found in the dead-roasted calcines produced from microwave roasting of this chalcopyrite concentrate were the hematite (Fe2O3), franklinite (ZnFe2O4), copper-rich ferrite (Cu1-xZnxFe2O4, x ≤ 0.5), and copper ferrite (CuFe2O4). The findings of this work indicated that it was technologically feasible to oxidize the chalcopyrite with microwaves using a 2.45 GHz multimode applicator.

  16. Thermo-Exfoliated Graphite Containing CuO/Cu2(OH3NO3:(Co2+/Fe3+ Composites: Preparation, Characterization and Catalytic Performance in CO Conversion

    Directory of Open Access Journals (Sweden)

    Vladyslav V. Lisnyak

    2010-01-01

    Full Text Available Thermo-exfoliated graphite (TEG/CuO/Cu2(OH3NO3:(Co2+/Fe3+ composites were prepared using a wet impregnation method and subsequent thermal treatment. The physicochemical characterization of the composites was carried out by powder X-ray diffraction (PXRD, scanning electron microscopy (SEM and Ar temperature-desorption techniques. The catalytic efficiency toward CO conversion to CO2 was examined under atmospheric pressure. Characterization of species adsorbed over the composites taken after the activity tests were performed by means of temperature programmed desorption massspectrometry (TPD MS. (TEG/CuO/Cu2(OH3NO3:(Co2+/Fe3+ composites show superior performance results if lower temperatures and extra treatment with H2SO4 or HNO3 are used at the preparation stages. The catalytic properties enhancements can be related to the Cu2(OH3NO3 phase providing reaction centers for the CO conversion. It has been found that prevalence of low-temperature states of desorbed CO2 over high-temperature ones in the TPD MS spectra is characteristic of the most active composite catalysts.

  17. 磷含量对Cu-Fe-P合金组织与性能的影响%Effect of P content on microstructure and property of Cu-Fe-P alloys

    Institute of Scientific and Technical Information of China (English)

    董琦祎; 汪明朴; 贾延琳; 陈畅; 夏承东

    2013-01-01

    Microstructure of cold roiled and aged Cu-2.3Fe-0.6P-0.2Zn alloy were observed by OM and SEM,and compared with that of Cu-2.3Fe-0.05P-0.2Zn(C194) alloy.The hardness and relative electrical conductivity of the alloys were measured.The results show that Fe2P phase is the main form of P in the as-cast alloy,a part of Fe2P is solid-solutioned in matrix,and the rest up to 10μm are dispersed in the alloy,which can not be eliminated by subsequent heat treatment.The performance of rolled Cu-2.3Fe-0.6P-0.2Zn alloy is better than the C194 alloy,but its conductivity improvement rate is slower than C194 alloy during aging,due to the low concentration of solute atoms and low driving force of precipitation.The micron Fe2P particles will stimulate recrystallization,and worsen the heat resistance of Cu-2.3Fe-0.6P-0.2Zn alloy.Consequently,the P content of C194 alloy should be controlled.%通过显微硬度及相对电导率测试、光学显微镜和扫描电镜观察,研究了Cu-2.3Fe-0.05P-0.2Zn (C194)合金与Cu-2.3Fe-0.6P-0.2Zn合金冷轧态与时效态的组织与性能.结果表明:添加0.6%P元素,铜合金内部形成大量Fe2P相,一部分固溶到基体,一部分以颗粒形式弥散存在于合金内,尺寸可达10μm,后续热处理难以消除;Cu-2.3 Fe-0.6P-0.2Zn合金的初始加工态性能优于C194合金,但基体中Fe溶质原子的浓度低,电导率上升速率变低;微米级Fe2P颗粒会激发再结晶,再结晶软化作用使得Cu-2.3Fe-0.6P-0.2Zn合金耐热性能低于C194合金.对于C194合金,P不宜过量.

  18. The content of Ca, Cu, Fe, Mg and Mn and antioxidant activity of green coffee brews.

    Science.gov (United States)

    Stelmach, Ewelina; Pohl, Pawel; Szymczycha-Madeja, Anna

    2015-09-01

    A simple and fast method of the analysis of green coffee infusions was developed to measure total concentrations of Ca, Cu, Fe, Mg and Mn by high resolution-continuum source flame atomic absorption spectrometry. The precision of the method was within 1-8%, while the accuracy was within -1% to 2%. The method was used to the analysis of infusions of twelve green coffees of different geographical origin. It was found that Ca and Mg were leached the easiest, i.e., on average 75% and 70%, respectively. As compared to the mug coffee preparation, the rate of the extraction of elements was increased when infusions were prepared using dripper or Turkish coffee preparation methods. Additionally, it was established that the antioxidant activity of green coffee infusions prepared using the mug coffee preparation was high, 75% on average, and positively correlated with the total content of phenolic compounds and the concentration of Ca in the brew.

  19. Sintered Fe-Ni-Cu-Sn-C Alloys Made of Ball-Milled Powders

    Directory of Open Access Journals (Sweden)

    Romański A.

    2014-10-01

    Full Text Available The main objective of this paper was to perform sinterability studies of ball-milled Fe-12%Ni-6.4%Cu-1.6%Sn-0.6%C powders. A mixture of precisely weighed amounts of elemental iron, nickel and graphite, and pre-alloyed 80/20 bronze powders was ball-milled for 8, 30 and 120 hours. After cold-pressing at 400 MPa the specimens were sintered at 900oC for 30 minutes in a reducing atmosphere and subsequently tested for density and hardness as well as subjected to structural studies using scanning electron microscopy (SEM and X-ray diffraction (XRD analysis.

  20. Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

    International Nuclear Information System (INIS)

    We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing

  1. Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Alves, M. J. P.; Gonzalez-Chavez, D. E.; Sommer, R. L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2015-03-28

    We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing.

  2. Magnetic Properties Of Amorphous And Nanocrystalline FeNiZrCuB Alloys

    International Nuclear Information System (INIS)

    The coercive fields Hc, saturation magnetizations Js and magnetostrictions λs of the amorphous Fe86-xNixZr7Cu1B6 alloys different contents of Ni(0-86 at.%) were investigated at room temperature. Thermomagnetic analyses by means of initial AC permeability and resistivity at the amorphous and nanocrystalline states of the investigated alloys were performed up to 5500 C. It was found that additions of Ni up to x = 33 at.% cause an increase of Hc, Js, λs. Additions of Ni (x = 0 - 43) cause drastic increase of the Curie temperature from 71 deg C for x 0at.% to 373 deg C for x = 43at.% of Ni. Higher concentration of Ni causes a decrease of Hc, Js, λs and Tc. (Authors)

  3. Regulatory Effects of Cu, Zn, and Ca on Fe Absorption: The Intricate Play between Nutrient Transporters

    Directory of Open Access Journals (Sweden)

    Nathalie Scheers

    2013-03-01

    Full Text Available Iron is an essential nutrient for almost every living organism because it is required in a number of biological processes that serve to maintain life. In humans, recycling of senescent erythrocytes provides most of the daily requirement of iron. In addition, we need to absorb another 1–2 mg Fe from the diet each day to compensate for losses due to epithelial sloughing, perspiration, and bleeding. Iron absorption in the intestine is mainly regulated on the enterocyte level by effectors in the diet and systemic regulators accessing the enterocyte through the basal lamina. Recently, a complex meshwork of interactions between several trace metals and regulatory proteins was revealed. This review focuses on advances in our understanding of Cu, Zn, and Ca in the regulation of iron absorption. Ascorbate as an important player is also considered.

  4. Domain wall pinning in FeCoCu bamboo-like nanowires.

    Science.gov (United States)

    Berganza, Eider; Bran, Cristina; Jaafar, Miriam; Vázquez, Manuel; Asenjo, Agustina

    2016-01-01

    The three dimensional nature of cylindrical magnetic nanowires has opened a new way to control the domain configuration as well as the magnetization reversal process. The pinning effect of the periodic diameter modulations on the domain wall propagation in FeCoCu individual nanowires is determined by Magnetic Force Microscopy, MFM. A main bistable magnetic configuration is firstly concluded from MFM images characterized by the spin reversal between two nearly single domain states with opposite axial magnetization. Complementary micromagnetic simulations confirm a vortex mediated magnetization reversal process. A non-standard variable field MFM imaging procedure allows us to observe metastable magnetic states where the propagating domain wall is pinned at certain positions with enlarged diameter. Moreover, it is demonstrated that it is possible to control the position of the pinned domain walls by an external magnetic field. PMID:27406891

  5. A new combined process for efficient removal of Cu(II) organic complexes from wastewater: Fe(III) displacement/UV degradation/alkaline precipitation.

    Science.gov (United States)

    Xu, Zhe; Gao, Guandao; Pan, Bingcai; Zhang, Weiming; Lv, Lu

    2015-12-15

    Efficient removal of heavy metals complexed with organic ligands from water is still an important but challenging task now. Herein, a novel combined process, i.e., Fe(III)-displacement/UV degradation/alkaline precipitation (abbreviated as Fe(III)/UV/OH) was developed to remove copper-organic complexes from synthetic solution and real electroplating effluent, and other processes including alkaline precipitation, Fe(III)/OH, UV/OH were employed for comparison. By using the Fe(III)/UV/OH process, some typical Cu(II) complexes, such as Cu(II)-ethylenediaminetetraacetic acid (EDTA), Cu(II)-nitrilotriacetic acid (NTA), Cu(II)-citrate, Cu(II)-tartrate, and Cu(II)-sorbate, each at 19.2 mg Cu/L initially, were efficiently removed from synthetic solution with the residual Cu below 1 mg/L. Simultaneously, 30-48% of total organic carbon was eliminated with exception of Cu(II)-sorbate. Comparatively, the efficiency of other processes was much lower than the Fe(III)/UV/OH process. With Cu(II)-citrate as the model complex, the optimal conditions for the combined process were obtained as: initial pH for Fe(III) displacement, 1.8-5.4; molar ratio of [Fe]/[Cu], 4:1; UV irradiation, 10 min; precipitation pH, 6.6-13. The mechanism responsible for the process involved the liberation of Cu(II) ions from organic complexes as a result of Fe(III) displacement, decarboxylation of Fe(III)-ligand complexes subjected to UV irradiation, and final coprecipitation of Cu(II) and Fe(II)/Fe(III) ions. Up to 338.1 mg/L of Cu(II) in the electroplating effluent could be efficiently removed by the process with the residual Cu(II) below 1 mg/L and the removal efficiency of ∼99.8%, whereas direct precipitation by using NaOH could only result in total Cu(II) removal of ∼8.6%. In addition, sunlight could take the place of UV to achieve similar removal efficiency with longer irradiation time (90 min).

  6. Monitoring of Cu, Fe, Ni, and Zn in wastewater during treatment in a horizontal rotating tubular bioreactor.

    Science.gov (United States)

    Zeiner, Michaela; Rezić, Tonci; Santek, Bozidar

    2010-02-01

    The most appropriate systems for treatment of metal-contaminated waters are bioreactors with microbial biofilms. A horizontal rotating tubular bioreactor (HRTB) was studied for its applicability for removing copper, iron, nickel, and zinc (Cu, Fe, Ni, and Zn) from wastewater. Monitoring of the concentrations of Cu, Fe, Ni, and Zn by a fast, simple, onsite method was needed to make decisions for further optimization. The UV-VIS spectrophotometric quantification of Cu, Fe, Ni, and Zn using sodium diethyldithiocarbamate, 1,10-phenathroline, dimethylglyoxime, and 2-{[alpha-(2-Hydroxy-5-sulfophenylazo)-benzylidene]-hydrazino}-benzoic acid monosodium salt (=zincon monosodium salt) as reagents, respectively, was optimized and validated. The limits of quantification were 0.14, 0.12, 0.21, and 0.03 mg/L for Cu, Fe, Ni and Zn, respectively. The recovery for all elements was between 98 and 104%, the uncertainty of measurement was less than 6%. Depending on the reactor parameters applied, metal removals from 40 to more than 90% could be obtained. PMID:20183985

  7. Grain boundary character distribution of CuNiSi and FeNi alloys processed by severe plastic deformation

    Science.gov (United States)

    Azzeddine, H.; Baudin, T.; Helbert, A. L.; Brisset, F.; Larbi, F. Hadj; Tirsatine, K.; Kawasaki, M.; Bradai, D.; Langdon, T. G.

    2015-04-01

    In this work the Grain Boundary Character Distribution (GBCD) in general and the relative proportion of low-Σ CSL (Coincidence Site Lattice) grain boundaries are determined through EBSD in Cu-2.5Ni-0.6Si (wt.%) and Fe-36Ni (wt.%) alloys after processing by high-pressure torsion, equal- channel angular pressing and accumulative roll bonding.

  8. Synthesis and Characterization of Macrocomposites Based on Nickel-Coated Quasi-Crystalline Al-Cu-Fe Powder

    NARCIS (Netherlands)

    Ivanov, A. S.; Kruglov, V. S.; Pal, A. F.; Ryabinkin, A. N.; Serov, A. O.; Shaitura, D. S.; Starostin, A. N.; Gavrikov, A. V.; Petrov, O. F.; Fortov, V. E.

    2011-01-01

    Disperse composite materials consisting of quasi-crystalline Al-Cu-Fe particles covered by nickel nanolayers have been obtained using a dusty plasma trap coating technology. These powders were processed into macrocomposites by cold pressing with subsequent sintering in hydrogen. The macrocomposites

  9. Meta-analysis of Zn, Cu and Fe in the hair of Chinese children with recurrent respiratory tract infection.

    Science.gov (United States)

    Mao, Song; Zhang, Aihua; Huang, Songming

    2014-10-01

    Trace elements play an important role in maintaining the normal metabolic and immune function. The onset of recurrent respiratory tract infection (RRI) is associated with the immune function, genetic factors and nutritional status. However, the association between the levels of trace elements and RRI remains inconclusive. We aimed to investigate the alterations of hair levels of zinc (Zn), copper (Cu) and iron (Fe) in Chinese children with RRI by performing a meta-analysis. A predefined electronic databases search was performed to identify eligible studies for the analysis of hair Zn, Cu or Fe levels in Chinese children with RRI. Thirteen studies were included. RRI patients displayed significantly lower levels of hair Zn (13 studies, random effects SMD: - 1.215, 95% CI: - 1.704 to - 0.725, p < 0.0001), Cu (11 studies, random effects SMD: - 0.384, 95% CI: - 0.717 to - 0.052, p = 0.023) and Fe (12 studies, random effects SMD: - 0.569, 95% CI: - 0.827 to - 0.312, p < 0.0001) compared with controls. No evidence of publication bias was observed. Sensitivity analysis did not change the results significantly. In conclusion, the deficiency of Zn, Cu and Fe may be contributing factors for the susceptibility of RRI in Chinese children. However, more studies in different ethnicities should be performed in the future.

  10. Mossbauer studies of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    1996-01-01

    This paper reports a Mossbauer study of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy between 10 and 673 K. The Curie temperature Tc is found to be 620-+ 1 K. The temperature dependence of the reduced average hyperfine field can be explained on the basis of Handrich's model of amorphous ferromagnetism...

  11. Influence of quench rates on the properties of rapidly solidified FeNbCuSiB alloy

    Indian Academy of Sciences (India)

    A K Panda; I Chattoraj; S Basu; A Mitra

    2002-11-01

    FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques. The crystallization, magnetic, mechanical and corrosion behaviour were studied for the prepared materials as a function of quenching rate from liquid to the solid state. Higher quench rates produced a more amorphous structure exhibiting superior soft magnetic properties with improved corrosion resistance.

  12. Multilayer epitaxial growth of lead phthalocyanine and C(70) using CuBr as a templating layer for enhancing the efficiency of organic photovoltaic cells.

    Science.gov (United States)

    Kim, Tae-Min; Shim, Hyun-Sub; Choi, Min-Soo; Kim, Hyo Jung; Kim, Jang-Joo

    2014-03-26

    The molecular orientation and crystallinity of donor and acceptor molecules are important for high-efficiency organic photovoltaic cells (OPVs) because they significantly influence both the absorption of light and charge-transport characteristics. We report that the templating effect extends to multilayers to increase the crystallinity and to modify the orientation of the crystals of lead phthalocyanine (PbPc) and C70 layers at the same time by adopting CuBr as a new templating layer on indium tin oxide (ITO). The formation of a monoclinic phase with a preferred orientation of (320) for PbPc and a fcc phase with a preferred orientation of (220) for C70 on the PbPc layer is revealed by X-ray diffraction (XRD) patterns. The multilayer epitaxy results in an increase of the exciton diffusion lengths from 5.6 to 8.8 nm for PbPc and from 6.9 to 13.8 nm for C70 to enhance the power conversion efficiency (PCE) of the planar heterojunction OPVs composed of PbPc and C70 from 1.4 to 2.3%. The quasi-epitaxy model is proposed to explain the multilayer epitaxy.

  13. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    Directory of Open Access Journals (Sweden)

    J. Mao

    2013-01-01

    Full Text Available The hydroperoxyl radical (HO2 is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions Cu(I/Cu(II and Fe(II/Fe(III to rapidly convert HO2 to H2O in aqueous aerosols. The implied HO2 uptake and conversion to H2O significantly affects global model predictions of tropospheric OH, ozone, carbon monoxide (CO and other species, improving comparisons to observations in the GEOS-Chem model. It represents a previously unrecognized positive radiative forcing of aerosols through the effects on the chemical budgets of major greenhouse gases including methane and hydrofluorocarbons (HFCs.

  14. A study on atomic skips in AlFeCu perfect quasicrystals: application of the isotopic substitution method in neutron diffusion; Etude des sauts atomiques dans les quasicristaux parfaits AlFeCu: une application de la methode de substitution isotopique dans la diffusion des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Coddens, G. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Soulie, E. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules

    1994-12-31

    In order to better understand the crystal structure and the atomic skip or phason in quasi-crystals, three samples of the AlFeCu ternary alloy have been experimentally studied: Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} (perfect sample), Al{sub 63}Cu{sub 24.5}Fe{sub 12.5} (non-perfect sample), Al{sub 50}Cu{sub 25}Fe{sub 25} (beta phase). Quasielastic neutron scattering variations with temperature and Q were recorded and signals have been enhanced through the use of isotope labelled samples. 4 figs., 2 tabs., 19 refs.

  15. Large magnetic anisotropy in strained Fe/Co multilayers on AuCu and the effect of carbon doping

    Directory of Open Access Journals (Sweden)

    G. Giannopoulos

    2015-04-01

    Full Text Available A tetragonally distorted FeCo structure is obtained in Fe/Co multilayers epitaxially grown on Au50Cu50 buffer using MgO single crystal substrates as a result of the lattice mismatch between the buffer and the FeCo ferromagnetic layer. The presence of large magnetic anisotropy energy (MAE of the order of 1 MJ/m3 has been confirmed by ferromagnetic resonance. Furthermore, the effect of carbon (C doping to maintain the tetragonal distortion throughout the thickness of 3 nm FeCo has been investigated. Our study shows that FeCo alloys maintain large magnetic moment and possess high MAE properties that are required for designing permanent magnets.

  16. Spectroscopic and electrochemical characterization of the surface layers of chalcopyrite (CuFeS{sub 2}) reacted in acidic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Mikhlin, Yuri L.; Tomashevich, Yevgeny V.; Asanov, Igor P.; Okotrub, Alexander V.; Varnek, Vladimir A.; Vyalikh, Denis V

    2004-03-30

    XPS, Fe L{alpha},{beta} and Cu L{alpha},{beta} X-ray emission and Fe L-, Cu L-, S L-edge and O K-edge absorption spectroscopies, Moessbauer spectroscopy and cyclic voltammetry were applied to study reacted surface layers of natural chalcopyrite, CuFeS{sub 2}. The surfaces became metal-depleted after the anodic oxidation in 1 M HCl and the leaching in 1 M H{sub 2}SO{sub 4}+0.2 M Fe{sub 2}(SO{sub 4}){sub 3} or 1 M HCl+0.4 M FeCl{sub 3} solutions, with the sulfur excess and iron/copper ratio been higher in the last instance, and were enriched in copper after the electrochemical reduction. The electronic structures of the metal-deficient layers up to several tenths of micrometer thick were similar to that of chalcopyrite, except that the density of the highest occupied states depended on sulfur anions formed (predominant S{sub 3}-anions after the ferric sulfate treatment, S{sub 4}-anions after the ferric chloride leaching or the potential sweep to 0.9 V, etc.). The layers created by the preliminary oxidation had only a small effect on the chalcopyrite voltammetry. We suggest a new reaction mechanism considering a role of the surface changes, including disordering and Anderson localization of the electronic states.

  17. Static and dynamic interaction between π and d electrons in organic superconductor β″-(BEDT-TTF)4[(H3O ) Fe (C2O4)3] .C6H5Br studied by 13C NMR spectroscopy

    Science.gov (United States)

    Ihara, Y.; Futami, Y.; Kawamoto, A.; Matsui, K.; Goto, T.; Sasaki, T.; Benmansour, S.; Gómez-García, C. J.

    2016-08-01

    We present the results of 13C NMR experiments in an organic superconductor with localized Fe spins β″-(BEDT-TTF) 4[(H3O ) Fe (C2O4)3] .C6H5Br . We reveal the antiferromagnetic coupling between Fe d spins and π spins, which creates an exchange field antiparallel to the external field direction at the π electrons. In addition to the static effects of Fe spins, we show from the nuclear spin-lattice relaxation rate measurement that the magnetic fluctuations generated by Fe spins are suppressed at low temperatures and high magnetic fields. These conditions are suitable to stabilize the field-induced superconductivity by the field compensation mechanism. After the suppression of Fe-spin dynamics by a magnetic field of 19 T, we observed the underlying π -electron contribution. We discuss a possible anomaly in the π -electron system.

  18. Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2014-09-01

    Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

  19. Microstructure Evolution in a Rapidly Solidified Cu85Fe15 Alloy Undercooled into the Metastable Miscibility Gap

    Institute of Scientific and Technical Information of China (English)

    Jie HE; Jiuzhou ZHAO

    2005-01-01

    A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to investigate the process of liquid-liquid phase transformation. The numerical results indicate that the minority phase droplets are nucleated in a temperature region around the peak of the supersaturation. The average radius of the Fe-rich droplets decreases and the number density of the minority phase droplets increases with decreasing the atomized droplet size.The simulated results were compared with the experimental ones. The kinetic process of the liquid-liquid phase transformation was discussed in detail.

  20. Ferromagnetic Fe on Cu(001) throughout the fcc-like phase: arguing from the viewpoint of the electronic structure.

    Science.gov (United States)

    Donath, M; Pickel, M; Schmidt, A B; Weinelt, M

    2009-04-01

    The scientific enthusiasm for ultrathin Fe films on Cu(001) has now lasted for more than 20 years. Is there ferromagnetic iron with a face-centred cubic (fcc) structure? Does ferromagnetism in Fe hinge on the body-centred cubic (bcc) structure? In this contribution, we try to establish that the electron system gives evidence of ferromagnetic behaviour with fcc-like electronic bands. We examine a crystal-induced surface state, which is characteristic of fcc surface order. Furthermore, we compare electronic signatures of fcc and bcc: the d-band exchange splitting, image-potential-state energies and the work function. We conclude that, from the viewpoint of the electronic structure, Fe on Cu(001) is found to be ferromagnetic throughout the fcc-like phase. This result raises a new question: how much deviation from the relaxed fcc order is acceptable without losing the electronic signature of fcc?

  1. Synthesis of magnetic porous Fe3O4/C/Cu2O composite as an excellent photo-Fenton catalyst under neutral condition.

    Science.gov (United States)

    Chai, Fanfan; Li, Keyan; Song, Chunshan; Guo, Xinwen

    2016-08-01

    Magnetic porous Fe3O4/C/Cu2O composites were prepared by a simple two-step process. Porous Fe3O4/C was synthesized via calcining iron tartrate precursor and then Cu2O was composited with Fe3O4/C by a precipitation-reduction method. The as-prepared samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) elemental mapping. Results show that Fe3O4/C has porous nanorod structure, which is composed of numerous small nanoparticles of about 50nm. Fe3O4 and carbon are uniformly distributed in the Fe3O4/C/Cu2O composite and Cu2O is dispersed on the surface of Fe3O4/C. Fe3O4/C/Cu2O composite exhibits excellent photo-Fenton catalytic performance for the degradation of methylene blue (MB) under visible light irradiation and neutral pH conditions, and MB (100mg/L) could be almost completely removed within 60min. The composite shows good recyclability and could be conveniently separated by an applied magnetic field. These results demonstrate that the Fe3O4/C/Cu2O composite is a powerful Fenton-like catalyst for degradation of organic pollutants from wastewater. PMID:27161809

  2. Influence of Fe-rich intermetallics on solidification defects in Al–Si–Cu alloys

    International Nuclear Information System (INIS)

    To better understand the influence of Fe-rich intermetallics on solidification defect formation, fast in situ synchrotron X-ray tomographic microscopy experiments were performed on a commercial A319 alloy (Al–7.5Si–3.5Cu, wt.%) with 0.2 and 0.6 wt.% Fe. Real-time observations during solidification and semi-solid deformation experiments reveal that β-intermetallics contribute via several different mechanisms to porosity formation and hot tearing susceptibility. While β-intermetallics were not observed to nucleate porosity directly, they do block interdendritic channels, thereby reducing the shrinkage feeding, and increasing pore tortuosity. Pores also grow preferentially along the surface of the β-intermetallics, suggesting that the β-phase has a lower gas–solid interfacial energy than α-Al, thus assisting in increasing pore volume. During uniaxial tension experiments, the ductile failure of the semi-solid, intermetallic-poor, base alloy transitions to a brittle-like failure when a large amount of β-intermetallics are present. In all post-failure microstructures, internal damage was preferentially orientated perpendicular to the loading direction, agreeing with prior experimental and numerical studies

  3. Magnetostatic coupling of 90 domain walls in FeNi/Cu/Co trilayers

    Energy Technology Data Exchange (ETDEWEB)

    Kurde, Julia; Miguel, Jorge; Kuch, Wolfgang [Freie Universitaet, Berlin (Germany); Bayer, Daniela; Aeschlimann, Martin [Technische Universitaet, Kaiserslautern (Germany); Sanchez-Barriga, Jaime; Kronast, Florian; Duerr, Herrmann A. [Helmholtz-Zentrum Berlin fuer Materialien und Energie (Germany)

    2011-07-01

    The magnetic interlayer coupling of FeNi/Cu/Co trilayered microstructures has been studied by means of X-ray magnetic circular dichroism in combination with photoelectron emission microscopy (XMCD-PEEM). We find that a parallel coupling between magnetic domains coexists with a non-parallel coupling between magnetic domain walls of each ferromagnetic layer. We attribute the non-parallel coupling of the two magnetic layers to local magnetic stray fields arising at domain walls in the magnetically harder Co layer. In the magnetically softer FeNi layer non-ordinary domain walls such as 270 and 90 domain walls with overshoot of the magnetization either inwards or outwards relative to the turning direction of the Co magnetization are identified. Micromagnetic simulations reveal that in the absence of magnetocrystalline anisotropy, both types of overshooting domain walls are energetically equivalent. However, if a uniaxial in-plane anisotropy is present, the relative orientation of the domain walls with respect to the anisotropy axis determines which of these domain walls is energetically favorable.

  4. Electronic structure and bonding in metal porphyrins, metal=Fe, Co, Ni, Cu, Zn

    Science.gov (United States)

    Liao, Meng-Sheng; Scheiner, Steve

    2002-07-01

    A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of MTPPx ions (x=2+, 1+, 1-, 2-, 3-, 4-), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as 3A2g, which arises from the configuration (dxy)2(dz2)2 (dxz)1(dyz)1. The calculated M-TPP binding energies, ionization potentials, and electron affinities are in good agreement with available experimental data. The influence of axial ligands and peripheral substitution by fluorine are in accord with the experimental observation that not only half-wave potentials (E1/2) of electrode reactions, but also the site of oxidation/reduction, may be dependent on the porphyrin basicity and the type of axial ligand coordination.

  5. Scattering of atomic and molecular ions from single crystal surfaces of Cu, Ag and Fe

    International Nuclear Information System (INIS)

    This thesis deals with analysis of crystal surfaces of Cu, Ag and Fe with Low Energy Ion scattering Spectroscopy (LEIS). Different atomic and molecular ions with fixed energies below 7 keV are scattered by a metal single crystal (with adsorbates). The energy and direction of the scattered particles are analysed for different selected charge states. In that way information can be obtained concerning the composition and atomic and electronic structure of the single crystal surface. Energy spectra contain information on the composition of the surface, while structural atomic information is obtained by direction measurements (photograms). In Ch.1 a description is given of the experimental equipment, in Ch.2 a characterization of the LEIS method. Ch.3 deals with the neutralization of keV-ions in surface scattering. Two different ways of data interpretation are presented. First a model is treated in which the observed directional dependence of neutralization action of the first atom layer of the surface is presented by a laterally varying thickness of the neutralizing layer. Secondly it is shown that the data can be reproduced by a more realistic, physical model based on atomic transition matrix elements. In Ch.4 the low energy hydrogen scattering is described. The study of the dissociation of H2+ at an Ag surface r0230ted in a model based on electronic dissociation, initialized by electron capture into a repulsive (molecular) state. In Ch.5 finally the method is applied to the investigation of the surface structure of oxidized Fe. (Auth.)

  6. Study of the behaviour of the dielectric constant in Cu, Fe: BaTiO3

    Institute of Scientific and Technical Information of China (English)

    Alioune OUEDRAOGO; Kalifa PALM; Issaka OUEDRAOGO; Guy CHANUSSOT

    2008-01-01

    In this work we study the behaviour of the dielectric constant of BaTiO3 single crystals doped with Cu and Fe for different ion percentages, particularly, the influence of these heterovalent substitutions on the ferroelectric-paraelectric phase transition whose temperature is found at Tc=120 ℃ for pure samples. The dielectric constant ε in terms of temperature shows that the Curie temperature decreases when the quantity of impurities increases and presents a broadening and flattering of the maximum of ε(T) within higher values, with the transition becoming more and more diffuse. It is interesting to have a material with very high permittivity (high-k) because of its capacity to store an important quantity of electric charges. The ε anisotropy and the Curie-Weiss law are also verified with a good ratio between the slopes ofε-1(T) from both sides of the transition, leading to a Curie constant: C= 13×104 K for BaTiO3:1.6%Fe in the polar phase. BaTiO3 is a displacive ferroelectric going through a first-order phase transition. The substitutions have an effect on the dynamics of the perovskite lattice. They induce charges transfer to Ti and a diminution of elastic forces in BaTiO3. Then we discuss the fact that the maximum of permittivity does not depend on the phase transition but on the nature of the material.

  7. Effects of Fe-deficiency on magnetic properties and Brillouin function characteristics for NiCuZn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linglong; Yu, Zhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yang, Yan [Department of Communication Engineering, Chengdu Technological University, Chengdu 611730 (China); Guo, Rongdi; Jiang, Xiaona; Sun, Ke; Wu, Chuanjian; Lan, Zhongwen [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2015-08-01

    The polycrystalline Ni{sub 0.56}Cu{sub 0.10}Zn{sub 0.34}Fe{sub 2−x}O{sub 4−3/2x} (x=0.00~0.14) ferrites have been prepared by conventional oxide ceramics process. The effects of Fe-deficiency content on magnetic properties and Brillouin function characteristics for NiCuZn ferrites have been investigated in details. With the increase of Fe-deficiency content, the opposite variation trend are observed for the saturation magntic induction B{sub s} and the coercivity H{sub c}. More importantly, based on the Néel molecular field theory, for the spinel ferrites which do not only contain Fe{sup 3+} but also some other multiple magnetic ions (Ni{sup 2+} and Cu{sup 2+}), the molecular field coefficients ω{sub aa}, ω{sub bb} and ω{sub ab=}ω{sub ba} are calculated by non-linear fitting method, and the Curie temperature T{sub c} formula has been modified. With the increase of Fe-deficiency content, the values of ω{sub aa} and ω{sub bb} increase gradually, however, the value of ω{sub ab}=ω{sub ba} has a contrary trend which results in the decrease of the Curie temperature. In addition, the fitting Curie temperatures values are coincided well with the Curie temperatures calculated by the modified formula. - Highlights: • Néel molecular field theory model of multi-magnetic ions (Fe{sup 3+}, Ni{sup 2+}, Cu{sup 2+}) is completed and the correlation formula of Curie temperature has been derived. • The calculating for the molecular field coefficients has been completed from absolute zero degree to Curie temperature. • The corresponding values and variation trend of molecular field coefficients have been completely investigated.

  8. Investigation of exchange bias in 0.1MFe2O4/0.9BiFeO3 (M=Co, Cu, Ni) nanocomposite

    International Nuclear Information System (INIS)

    The 0.1MFe2O4/0.9BiFeO3 (M=Co, Cu, Ni) nanocomposite samples were synthesized by the sol–gel method. Phase composition analysis was carried out, which showed that these bulk samples were composed of a ferrimagnetic MFe2O4 (M=Co, Cu, Ni) and a ferroelectric antiferromagnet (FEAF) BiFeO3 phases, respectively. The magnetic properties of all the samples were investigated by measuring their magnetization as a function of temperature and magnetic field. These results indicated that the magnetic hysteresis loops of 0.1CuFe2O4/0.9BiFeO3 sample sintered in air atmosphere at 550 °C for 3 h exhibited a negative shift and an enhanced coercivity at low temperature ascribed to strong exchange coupling between the BiFeO3 and CuFe2O4 grains. However, there were no magnetic hysteresis loops in both the 0.1CoFe2O4/0.9BiFeO3 sample and the 0.1NiFe2O4/0.9BiFeO3 sample. In view of these results, we tend to think the CuFe2O4/BiFeO3 nanocomposite system may be a useful multifunctional material. - Highlights: ► Exchange bias effect in ferroelectric antiferromagnet (FEAF)/ferromagnet (FM) nanocomposites. ► Exchange bias effect is only observed in the 0.1CuFe2O4/0.9BiFeO3 nanocomposite. ► Lower saturation magnetization is important for producing exchange bias in FEAF/FM system.

  9. Synthesis and characterization of the 1:1 adducts of copper(I) halides with bidentate N,N′-bis(benzophenone)-1,2-diiminoethane Schiff base: Crystal structures of [Cu(bz2en)2][CuX2] (X = Br, I) complexes

    NARCIS (Netherlands)

    Kia, Reza; Mirkhani, Valiollah; Harkema, Sybolt; Hummel, van Gerrit J.

    2007-01-01

    1:1 adducts of N,N′-bis(benzophenone)-1,2-diiminoethane (bz2en) with copper(I) chloride, bromide and iodide, [Cu(bz2en)2][CuX2] (X = Cl, Br, and I), have been synthesized and the structures of the solid bromide and iodide adducts were determined by X-ray crystallography from single-crystal data. The

  10. A novel reusable nanocomposite adsorbent, xanthated Fe3O4-chitosan grafted onto graphene oxide, for removing Cu(II) from aqueous solutions

    Science.gov (United States)

    Liu, Jinshui; Liu, Wenxiu; Wang, Yiru; Xu, Meijiao; Wang, Bin

    2016-03-01

    Novel nanocomposites of xanthated Fe3O4-chitosan grafted onto graphene oxide (xanthated Fe3O4-CS-GO) were successfully synthesized for the first time using an amidation reaction. The xanthated Fe3O4-CS-GO was used to remove Cu(II) from aqueous solutions. The xanthated Fe3O4-CS-GO was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, and energy dispersive X-ray spectroscopy. The Cu(II) adsorption isotherms for the xanthated Fe3O4-CS-GO fitted the Langmuir isotherm model. The maximum Cu(II) adsorption capacity of the xanthated Fe3O4-CS-GO was 426.8 mg g-1, which is much higher than the maximum adsorption capacities of other adsorbents that have been described in the literature. This was attributed to xanthated Fe3O4-CS-GO having abundant functional groups. The xanthated Fe3O4-CS-GO could be regenerated using ethylene diamine tetraacetic acid, and could easily be removed from a liquid using an external magnetic field. These features would allow secondary pollution of the environment to be avoided more easily than is the case for other adsorbents. Cu(II) was adsorbed from aqueous solutions quickly and efficiently by the xanthated Fe3O4-CS-GO complex, suggesting that xanthated Fe3O4-CS-GO may be an ideal candidate for removing Cu(II) from wastewater.

  11. Heterotrimetallic coordination polymers: {Cu(II)Ln(III)Fe(III)} chains and {Ni(II)Ln(III)Fe(III)} layers: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Alexandru, Maria-Gabriela; Visinescu, Diana; Andruh, Marius; Marino, Nadia; Armentano, Donatella; Cano, Joan; Lloret, Francesc; Julve, Miguel

    2015-03-27

    The use of the [Fe(III) (AA)(CN)4](-) complex anion as metalloligand towards the preformed [Cu(II) (valpn)Ln(III)](3+) or [Ni(II) (valpn)Ln(III) ](3+) heterometallic complex cations (AA=2,2'-bipyridine (bipy) and 1,10-phenathroline (phen); H2 valpn=1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu(II) (valpn)Ln(III) (H2O)3 (μ-NC)2 Fe(III) (phen)(CN)2 {(μ-NC)Fe(III) (phen)(CN)3}]NO3 ⋅7 H2O}n (Ln=Gd (1), Tb (2), and Dy (3)) and the trinuclear complex [Cu(II) (valpn)La(III) (OH2 )3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ]⋅NO3 ⋅H2O⋅CH3 CN (4) were obtained with the [Cu(II) (valpn)Ln(III)](3+) assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni(II) (valpn)Ln(III) (ONO2 )2 (H2 O)(μ-NC)3 Fe(III) (bipy)(CN)]⋅2 H2 O⋅2 CH3 CN}n (Ln=Gd (5), Tb (6), and Dy (7)) resulted with the related [Ni(II) (valpn)Ln(III) ](3+) precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu(II) (valpn)La(III) (OH2)3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ](+), nitrate counterions, and non-coordinate water and acetonitrile molecules. The heteroleptic {Fe(III) (bipy)(CN)4} moiety in 5-7 acts as a tris-monodentate ligand towards three {Ni(II) (valpn)Ln(III)} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu(II)-Ln(III) (1-3) and Ni(II)-Ln(III) (5-7) units, as well as through the single cyanide bridge between the Fe(III) and either Ni(II) (5-7) or Cu(II) (4) account for the overall ferromagnetic behavior observed in 1-7. DFT-type calculations were performed to substantiate the magnetic interactions in 1, 4, and 5. Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out-of-phase ac signals below 4.0 K in the lack of a dc field, the values of the pre

  12. Study of Fe-Cu/ZSM-5 and its amination catalytic property%Fe-Cu/ZSM-5催化剂及其胺化催化性能研究

    Institute of Scientific and Technical Information of China (English)

    赵锋伟; 淡保松; 王伟; 杨建明; 吕剑

    2009-01-01

    制备了一种Fe-Cu/ZSM-5胺化催化剂,考察其在乙醇胺选择性合成哌嗪、三乙烯二胺反应中的催化活性.结果表明,随着Fe、Cu负载量的增加,催化剂表面酸性逐渐向强酸方向位移,总酸量增加,反应转化率提高;Cu负载量对反应转化率及乙二胺选择性的影响相对较弱,但对哌嗪的生成有明显的促进作用;催化反应性能不仅受催化剂酸性的影响,还与负载组分的性质及负载组分与载体间的相互作用有关.%The synthesis of piperazine(PIP) and triethylene diamine (TEDA)from ethanolamine (MEA) with ammonia over Fe-Cu/ZSM-5 catalyst was investigated.The results showed that when Fe,Cu contents increased,the acid properties were raised,the acid amount and the conversion of MEA increased.The effective in conversion of MEA by Cu content was weaker,but evident to promte synthesis of piperazine.The reaction properties were not only influenced by the surface acid but also influenced by the properties of Fe,Cu.

  13. Cu_xFe_(1-x)O·Fe_2O_3磁流体纳米微粒的制备与性能分析%Preparation of nano-Cu_xFe_(1-x)O·Fe_2O_3 magnetic particles and performance analysis

    Institute of Scientific and Technical Information of China (English)

    季业; 邵慧萍; 林涛; 郭志猛

    2011-01-01

    为增强磁流体在肿瘤治疗中的靶向性,本研究在制备磁流体过程中加入Cu2+,利用超声乳化法制备纳米CuxFe1-xO.Fe2O3颗粒,采用壳聚糖作为表面活性剂制备出分散均匀、稳定性好的水基磁流体,研究了不同的Cu2+加入量和不同的壳聚糖用量对磁流体磁性能的影响.结果表明:壳聚糖成功包覆于磁性CuxFe1-xO.Fe2 O3颗粒的表面;不同Cu2+加入量制得的粉末同属立方晶系;当实验原理方程式中的x=0.1、壳聚糖溶液用量为20 mL(每50 mL质量分数为1%的CuxFe1-xO.Fe2 O3溶液)时进行表面改性制得的纳米磁流体具有较高的比饱和磁化强度及稳定性,静置30 d后,无明显沉降及分层现象,其比饱和磁化强度为56.43 A.m2.kg-1.%In order to increase the magnetic fluid in target-based in cancer treatment,the Cu2+ was studied in the preparation procedure.Nano-CuxFe1-xO·Fe2O3 magnetic particles were prepared by means of ultrasonic emulsion method,and then dispersed into water with chitosan as surfactants to make CuxFe1-xO·Fe2O3 magnetic fluid.The influence of Cu2+ addition and chitosan on the magnetic properties was studied.The results show that the surface of CuxFe1-xO·Fe2O3 nanoparticle is wrapped with chitosan.The CuxFe1-xO·Fe2O3 nanoparticles with different of the Cu2+ addition are cubic system.It is conducive to obtain the CuxFe1-xO·Fe2O3 magnetic fluid with a high saturation magnetization and stability when the condition for x=0.1 and chitosan solution dosage is 20 ml(every 50 ml of the CuxFe1-xO·Fe2O3 solution(1 % by weight)).Rest for 30 days,there is no obvious phenomenon of settled and stratified,and the saturation magnetization is 56.43 A·m2·kg-1.

  14. Study on the covalence of Cu and chemical bonding in an inorganic fullerene-like molecule, [CuCl]20[Cp*FeP5]12[Cu-(CH3CN)2+Cl-]5, by a density functional approach

    Institute of Scientific and Technical Information of China (English)

    WANG Bingwu; XU Guangxian; CHEN Zhida

    2004-01-01

    The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, {[CuCl]20[Cp*FeP5]12 [Cu(CH3CN)+2Cl-]5}, has been studied by a density functional approach. Geometrical optimization of the three basic structural units of the molecule is performed with Amsterdam Density Functional Program. The results are in agreement with the experiment. Localized MO's obtained by Boys-Foster method give a clear picture of the chemical bonding in this molecule. The reason why CuCl can react with Cp*FeP5 in solvent CH3CN to form the fullerene-like molecule is explained in terms of the soft-hard Lewis acid base theory and a new concept of covalence.

  15. The relationship between the crystallization process and the soft magnetic properties of nanocrystalline Fe endash M endash B endash Cu (M=Zr, Nb) alloy

    International Nuclear Information System (INIS)

    The relationship between the crystallization process and the soft magnetic properties of nanocrystalline Fe84Nb3.5Zr3.5B8Cu1 alloy has been studied by comparison with that of Fe73.5Si13.5B9Nb3Cu1 alloy. When the annealing temperature Ta is slightly above the crystallization temperature, high permeability can only be obtained for Fe endash Nb endash Zr endash B endash Cu after annealing for very short times. The Ta dependence of the coercive force of Fe endash Nb endash Zr endash B endash Cu cannot be explained by the change of the grain size of the bcc phase. The soft magnetic properties of Fe endash Nb endash Zr endash B endash Cu is dominated by not only the grain size but also the Curie temperature of the intergranular amorphous phase. It is concluded that the magnetic softness of Fe endash Nb endash Zr endash B endash Cu is related directly to the degree of the reduction in the apparent anisotropy, while that of Fe endash Si endash B endash Nb endash Cu is strongly affected by the Si content of the bcc phase. copyright 1997 American Institute of Physics

  16. Preparation of polypyrrole-coated CuFe2O4 and their improved electrochemical performance as lithium-ion anodes

    Institute of Scientific and Technical Information of China (English)

    Huayun Xu; Yunpo Wang; Long Zheng; Xinhui Duan; Lihui Wang; Jian Yang; Yitai Qian

    2014-01-01

    CuFe2O4 network, prepared via the electrostatic spray deposition technique, with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported. The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole (PPy). At the current density of 100 mA·g-1, Li/CuFe2O4 electrode delivers a reversible capacity of 842.9 mAh·g-1 while the reversible capac-ity of Li/PPy-coated CuFe2O4 electrode increases up to 1106.7 mAh·g-1. A high capacity of 640.7 mAh·g-1 for the Li/PPy-coated CuFe2O4 electrode is maintained in contrast of 398.9 mAh·g-1 for Li/CuFe2O4 electrode after 60 cycles, which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity. The electrochemical impedance spectroscopy (EIS) further reveals that the Li/PPy-coated CuFe2O4 electrode has a lower charge transfer resistance than the Li/CuFe2O4 electrode.

  17. Nanostructured Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode for efficient hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Dipika; Upadhyay, Sumant; Verma, Anuradha [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Satsangi, Vibha R. [Department of Physics Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 India (India); Shrivastav, Rohit [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Dass, Sahab, E-mail: drsahabdas@gmail.com [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India)

    2015-01-01

    Nanostructured thin films of pristine Fe{sub 2}O{sub 3}, Ti-doped Fe{sub 2}O{sub 3}, Cu{sub 2}O, and Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-doped Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction were deposited on tin-doped indium oxide (Sn:In{sub 2}O{sub 3}) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe{sub 2}O{sub 3}, Ti-Fe{sub 2}O{sub 3}, Cu{sub 2}O, Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm{sup 2} at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe{sub 2}O{sub 3} played a significant role in PEC response. • Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O.

  18. Nondestructive readout of holograms recorded by Bessel beam technique in LiNbO3:Fe and LiNbO3:Fe:Cu crystals

    Science.gov (United States)

    Badalyan, Anahit; Hovsepyan, Ruben; Mantashyan, Paytsar; Mekhitaryan, Vahram; Drampyan, Rafael

    2014-04-01

    Detailed and comparable investigations of the time evolution of the readout erasure of 1D and 2D annular symmetry photonic lattice structures optically induced by nondiffracting Bessel beam technique were performed. The lattices were recorded with the use of cw single mode 532 nm, 17 mW laser beam in photorefractive LiNbO3:Fe and LiNbO3:Fe:Cu crystals, the latter having also photochromic properties. While the 1D Bessel-like refractive lattice had micrometric scale modulation in the radial direction, the 2D complex lattices inducted by Bessel standing wave were a combination of annular and planar refractive gratings with ~10 μm period in the radial and half-wavelength standing wave 266 nm period in the axial directions. The study of photochromic properties of LN:Fe:Cu crystal at 532 nm showed 1.6 times increase of absorption coefficient with increase of illuminating intensity from 12.5 to 96.8 mW/cm2, which opened a direct way of essential decrease of the erasure of the stored lattices during readout by weaker probe beam at the recording wavelength. Investigations showed that the erasure constants for 1D and 2D lattices in LN:Fe:Cu crystal are larger than in LN:Fe crystal (6150 and 5150 s, and 3080 and 698 s, respectively). The nondestructive refractive lattices recorded by Bessel beam technique will assist the different applications in all optical devices and communication systems and have particular interest for experiments on light localization and spatial soliton formation in structured nonlinear media.

  19. Phase Equilibria Studies of the Cu-Fe-O-Si System in Equilibrium with Air and with Metallic Copper

    Science.gov (United States)

    Hidayat, Taufiq; Henao, Hector M.; Hayes, Peter C.; Jak, Evgueni

    2012-10-01

    Phase equilibria of the Cu-Fe-O-Si system have been investigated in equilibrium: (1) with air atmosphere at temperatures between 1373 K and 1673 K (1100 °C and 1400 °C) and (2) with metallic copper at temperatures between 1373 K and 1573 K (1100 °C and 1300 °C). High-temperature equilibration/quenching/electron-probe X-ray microanalysis (EPMA) techniques have been used to accurately determine the compositions of the phases in equilibrium in the system. The new experimental results are presented in the form of "Cu2O"-"Fe2O3"-SiO2 ternary sections. The relationships between the activity of CuO0.5(l) and the composition of slag in equilibrium with metallic copper are discussed. The phase equilibria information of the Cu-Fe-O-Si system is of practical importance for industrial copper production processes and for the improvement of the existing thermodynamic database of copper-containing slag systems.

  20. Hyperfine interaction and tuning of magnetic anisotropy of Cu doped CoFe2O4 ferrite nanoparticles

    Science.gov (United States)

    Batoo, Khalid Mujasam; Salah, Dina; Kumar, Gagan; Kumar, Arun; Singh, Mahavir; Abd El-sadek, M.; Mir, Feroz Ahmad; Imran, Ahamad; Jameel, Daler Adil

    2016-08-01

    Ferrimagnetic oxides may contain single or multi domain particles which get converted into superparamagnetic state near a critical size. To explore the existence of these particles, we have made Mössbauer and magnetic studies of Cu2+ substitution effect in CoFe2-xO4 Ferrites (0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). All the samples have a cubic spinel structure with lattice parameters increasing linearly with increase in Cu content. The hysteresis loops yield a saturation magnetization, coercive field, and remanent magnetization that vary significantly with Cu content. The magnetic hysteresis curves shows a reduction in saturation magnetization and an increase in coercitivity with Cu2+ ion substitution. The anisotropy constant, K1, is found strongly dependent on the composition of Cu2+ ions. The variation of saturation magnetization with increasing Cu2+ ion content has been explained in the light of Neel's molecular field theory. Mössbauer spectra at room temperature shows two ferrimagnetically relaxed Zeeman sextets. The dependence of Mössbauer parameters such as isomer shift, quadrupole splitting, line width and hyperfine magnetic field on Cu2+ ion concentration have been discussed.

  1. Competing magnetic ground states and their coupling to the crystal lattice in CuFe2Ge2

    Science.gov (United States)

    May, Andrew F.; Calder, Stuart; Parker, David S.; Sales, Brian C.; McGuire, Michael A.

    2016-01-01

    Identifying and characterizing systems with coupled and competing interactions is central to the development of physical models that can accurately describe and predict emergent behavior in condensed matter systems. This work demonstrates that the metallic compound CuFe2Ge2 has competing magnetic ground states, which are shown to be strongly coupled to the lattice and easily manipulated using temperature and applied magnetic fields. Temperature-dependent magnetization M measurements reveal a ferromagnetic-like onset at 228 (1) K and a broad maximum in M near 180 K. Powder neutron diffraction confirms antiferromagnetic ordering below TN ≈ 175 K, and an incommensurate spin density wave is observed below ≈125 K. Coupled with the small refined moments (0.5–1 μB/Fe), this provides a picture of itinerant magnetism in CuFe2Ge2. The neutron diffraction data also reveal a coexistence of two magnetic phases that further highlights the near-degeneracy of various magnetic states. These results demonstrate that the ground state in CuFe2Ge2 can be easily manipulated by external forces, making it of particular interest for doping, pressure, and further theoretical studies. PMID:27739477

  2. Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, M.; McGrath, R.; Sharma, H. R. [Surface Science Research Centre and The Department of Physics, The University of Liverpool, Liverpool L69 3BX (United Kingdom); Yadav, T. P. [Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Fournée, V.; Ledieu, J. [Institut Jean Lamour (UMR7198 CNRS-Université de Lorraine), Parc de Saurupt, 54011 Nancy Cedex (France)

    2015-03-07

    The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

  3. Effect of Cu substitution for Ni on the properties of NiFe/sub 2/O/sub 4/ system

    International Nuclear Information System (INIS)

    In a single phase from Ni/sub 1-x/ Cu/sub x/Fe/sub 2/O/sub 4/ ferrites, for x=0.0, 0.25, 0.75, 1.0 were produced by standard ceramic method. Electrical resistivity, mass density, x-ray density and porosity of each sample was measured. Room temperature resistivity shows a decreasing trend with Cu concentration, that may be due to the shifting of Fe/sup +2/ ions from octahedral to the tetrahedral sites. Temperature dependent dc resistivity decreases while mobility increases with increasing temperature, from 30-200 deg. centigrade, showing a semi-conducting behavior of these samples. The activation energy show a decrease with increasing Cu-content which is analogues to that of room temperature resistivity. The lattice parameter decreases linearly with the substitution of Cu. This may be attributed to the substitution of smaller Cu/sup +2/ (0.70 deg. A) ions for the large Ni/sup +2/ (0.78 deg. A) ions. (author)

  4. Microstructures of Fe77-xNixCu1Nb2P14B6 Soft Magnetic AlloysStudied by X-Ray Absorption Fine Structure

    Institute of Scientific and Technical Information of China (English)

    YIN Shi-Long; BIAN Qing; WEI Shi-Qiang

    2000-01-01

    Local structures of the mechanically alloyed Fe77-xNixCu1Nb2P14B6 soft magnetic materials have been in vestigated by x-ray absorption fine structure. The results show that mechanical alloying (MA) can drive the Fe77-xNixCu1Nb2P14B6 powder mixture to produce amorphous alloy when the atomic concentration of Fe ele ment is about and over 40%. On the contrary, the MA Fe77-xNixCu1Nb2P14B6 is a solid solution with an fcc-like structure in the region of lower Fe atomic concentration (< 22%), preserving a medium-range order around Ni and Fe atoms. Moreover, we have found that the local structure geometry of Fe atom is similar to that of Ni atom for all the MA Fer7-xNixCu1 Nb2P14B6 samples. It indicates that the local structures of Fe and Ni atoms in a Fe77-xNixCu1 Nb2P14B6 sample only depend on the x value of element Ni after ball milling.

  5. Magnetotransport properties of Co90Fe10/Cu/Ni80Fe20 pseudo-spin-valve with out-of-plane tilted magnetic field

    Science.gov (United States)

    Luo, Linqiang; Dao, Nam; Kittiwatanakul, Salinporn; Wolf, Stuart; Lu, Jiwei; UVa NanoStar Team

    The giant magnetoresistance (GMR) effect of a pseudo spin valve made of Co90Fe10/Cu/Ni80Fe20 has been investigated, with a magnetic field applied perpendicularly tilted to the sample plane. Without using a pinning layer, the magnetic separation of the free and fixed layers is uniquely achieved by utilizing perpendicular fields due to different anisotropy energies between Ni80Fe20 and Co90Fe10. The magneto-transport measurements are carried out by Van der Pauw method in current-in-plane geometry at room temperature. By tilting the magnetic field at different angles from out-of-plane, the GMR plateau's width can be tuned. A plateau width of about 2000 Oe is observed at tilted angle 0.5o, which opens a significantly larger window for high-resistance states comparing with a plateau width of 10 Oe for in-plane fields. With the out-of-plane tilted fields, the orientation of the magnetic moments can be tuned continuously out of the sample plane, and the relative orientation between Ni80Fe20 and Co90Fe10 can also be tuned by the tilted angle, enabling us to precisely control the sample's states for current-induced spin dynamics study that is very difficult in the case of in-plane applied magnetic fields.

  6. Phase transition from fcc to bcc structure of the Cu-clusters during nanocrystallization of Fe85.2Si1B9P4Cu0.8 soft magnetic alloy

    Directory of Open Access Journals (Sweden)

    Masahiko Nishijima

    2014-05-01

    Full Text Available A role of Cu on the nanocrystallization of an Fe85.2Si1B9P4Cu0.8 alloy was investigated by X-ray absorption fine structure (XAFS and transmission electron microscopy (TEM. The Cu K-edge XAFS results show that local structure around Cu is disordered for the as-quenched sample whereas it changes to fcc-like structure at 613 K. The fcc Cu-clusters are, however, thermodynamically unstable and begin to transform into bcc structure at 638 K. An explicit bcc structure is observed for the sample annealed at 693 K for 600 s in which TEM observation shows that precipitated bcc-Fe crystallites with ∼12 nm are homogeneously distributed. The bcc structure of the Cu-clusters transforms into the fcc-type again at 973 K, which can be explained by the TEM observations; Cu segregates at grain boundaries between bcc-Fe crystallites and Fe3(B,P compounds. Combining the XAFS results with the TEM observations, the structure transition of the Cu-clusters from fcc to bcc is highly correlated with the preliminary precipitation of the bcc-Fe which takes place prior to the onset of the first crystallization temperature, Tx1 = 707 K. Thermodynamic analysis suggests that an interfacial energy density γ between an fcc-Cu cluster and bcc-Fe matrix dominates at a certain case over the structural energy between fcc and bcc Cu, ΔGfcc − bcc, which causes phase transition of the Cu clusters from fcc to bcc structure.

  7. Phase transition from fcc to bcc structure of the Cu-clusters during nanocrystallization of Fe85.2Si1B9P4Cu0.8 soft magnetic alloy

    International Nuclear Information System (INIS)

    A role of Cu on the nanocrystallization of an Fe85.2Si1B9P4Cu0.8 alloy was investigated by X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM). The Cu K-edge XAFS results show that local structure around Cu is disordered for the as-quenched sample whereas it changes to fcc-like structure at 613 K. The fcc Cu-clusters are, however, thermodynamically unstable and begin to transform into bcc structure at 638 K. An explicit bcc structure is observed for the sample annealed at 693 K for 600 s in which TEM observation shows that precipitated bcc-Fe crystallites with ∼12 nm are homogeneously distributed. The bcc structure of the Cu-clusters transforms into the fcc-type again at 973 K, which can be explained by the TEM observations; Cu segregates at grain boundaries between bcc-Fe crystallites and Fe3(B,P) compounds. Combining the XAFS results with the TEM observations, the structure transition of the Cu-clusters from fcc to bcc is highly correlated with the preliminary precipitation of the bcc-Fe which takes place prior to the onset of the first crystallization temperature, Tx1 = 707 K. Thermodynamic analysis suggests that an interfacial energy density γ between an fcc-Cu cluster and bcc-Fe matrix dominates at a certain case over the structural energy between fcc and bcc Cu, ΔGfcc−bcc, which causes phase transition of the Cu clusters from fcc to bcc structure

  8. Phase transition from fcc to bcc structure of the Cu-clusters during nanocrystallization of Fe85.2Si1B9P4Cu0.8 soft magnetic alloy

    Science.gov (United States)

    Nishijima, Masahiko; Matsuura, Makoto; Takenaka, Kana; Takeuchi, Akira; Ofuchi, Hironori; Makino, Akihiro

    2014-05-01

    A role of Cu on the nanocrystallization of an Fe85.2Si1B9P4Cu0.8 alloy was investigated by X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM). The Cu K-edge XAFS results show that local structure around Cu is disordered for the as-quenched sample whereas it changes to fcc-like structure at 613 K. The fcc Cu-clusters are, however, thermodynamically unstable and begin to transform into bcc structure at 638 K. An explicit bcc structure is observed for the sample annealed at 693 K for 600 s in which TEM observation shows that precipitated bcc-Fe crystallites with ˜12 nm are homogeneously distributed. The bcc structure of the Cu-clusters transforms into the fcc-type again at 973 K, which can be explained by the TEM observations; Cu segregates at grain boundaries between bcc-Fe crystallites and Fe3(B,P) compounds. Combining the XAFS results with the TEM observations, the structure transition of the Cu-clusters from fcc to bcc is highly correlated with the preliminary precipitation of the bcc-Fe which takes place prior to the onset of the first crystallization temperature, Tx1 = 707 K. Thermodynamic analysis suggests that an interfacial energy density γ between an fcc-Cu cluster and bcc-Fe matrix dominates at a certain case over the structural energy between fcc and bcc Cu, ΔGfcc - bcc, which causes phase transition of the Cu clusters from fcc to bcc structure.

  9. Properties of Electroless Ni-Cu-P Plating Coating on Nd-Fe-B Permanent Magnets%烧结Nd-Fe-B永磁体化学镀Ni-Cu-P性能研究

    Institute of Scientific and Technical Information of China (English)

    于升学; 宋伟明; 邵光杰

    2001-01-01

    通过适当的预处理工艺,在烧结Nd-Fe-B永磁体表面直接实现化学镀Ni-Cu-P,不需要预镀处理.用X-射线衍射仪、扫描电镜分析了镀层的结构和表面形貌,测试了镀层的耐蚀性能和结合强度.结果表明,Nd-Fe-B永磁体经化学镀NiCu-P后,可以获得与基体结合良好、孔隙率低、耐蚀性高的镀层.

  10. A nuclear microscopy study of trace elements Ca, Fe, Zn and Cu in atherosclerosis

    International Nuclear Information System (INIS)

    Quantitative mapping of trace elements Ca, Fe, Zn and Cu can be achieved in biological tissue using a nuclear microprobe. Presented here is a brief review of the work we have carried out in the last decade using the nuclear microscope to try and elucidate the role of trace elements Fe, Zn, Cu and Ca in induced atherosclerosis in New Zealand White rabbits fed on a 1% cholesterol diet. The lesions were studied using nuclear microscopy, incorporating a combination of ion beam techniques: particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and scanning transmission ion microscopy (STIM). Iron is present in early lesions at concentrations around seven times higher than the artery wall. Measurements of localized lesion iron concentrations were observed to be highly correlated with the depth of the lesion in the artery wall for each individual animal, implying that local elevated concentrations may provide an accelerated process of atherosclerosis in specific regions of the artery. When the rabbits were kept mildly anaemic, thereby reducing iron levels in the lesion, the progression of the disease was significantly slowed. Iron chelation using desferal showed that early treatment (three weeks into the high fat diet) for relatively long periods (nine weeks) significantly retarded the progression of the disease. Zinc is depleted in the lesion and is also observed to be anti-correlated with local lesion development and feeding the rabbits on a high fat diet with zinc supplements inhibited lesion development, although since no significant increase in lesion zinc levels was measured, this anti-atherosclerotic effect may be indirect. Copper, measured at low levels (∼3 ppm) in the early lesion, is also depleted compared to the artery wall, suggesting that it is not a major factor in atherogenesis. Calcium is also depleted in early lesions, although at a later stage mineral deposition (hydroxyapatite) is observed to take place in the lesion

  11. ADSORPSI ION CU(II MENGGUNAKAN PASIR LAUT TERAKTIVASI H2SO4 DAN TERSALUT Fe2O3

    Directory of Open Access Journals (Sweden)

    DS Pambudi

    2014-11-01

    Full Text Available Pasir laut merupakan bahan alam yang melimpah. Selain digunakan sebagai bahan bangunan, pasir dapat dimanfaatkan sebagai penjerap ion logam berat mengingat 30% lebih dari volumenya adalah pori-pori. Tujuan penelitian adalah untuk mengetahui kapasitas adsorpsi ion logam Cu(II menggunakan pasir laut kontrol, pasir laut teraktivasi H2SO4, pasir laut tersalut Fe2O3, serta pasir laut teraktivasi H2SO4 dan tersalut Fe2O3. Ada dua macam pasir laut yang digunakan, yaitu pasir hitam dan pasir putih. Kajian yang dilakukan meliputi optimasi adsorben pada variasi pH, konsentrasi ion logam, dan waktu kontak. Optimasi pH diperoleh pada pH 7, optimasi konsentasi ion logam diperoleh 250 ppm untuk pasir hitam dan 200 ppm untuk pasir putih, dan optimasi waktu diperoleh 60 menit untuk pasir hitam dan 90 menit untuk pasir putih. Kapasitas adsorpsi pasir laut teraktivasi H2SO4 dan tersalut Fe2O3 dalam menyerap ion logam tembaga sebesar 24,8634 mg/g untuk pasir hitam dan 19,8854 mg/g untuk pasir putih. Sebanyak 6,5 g pasir hitam teraktivasi H2SO4 dan tersalut Fe2O3 digunakan untuk menyerap limbah pada konsentrasi Cu(II sebesar 2960,32 ppm dengan persentase teradsorpsi sebesar 94,70%. Sedangkan pada pasir putih teraktivasi H2SO4 dan tersalut Fe2O3, sebanyak 8 g pasir digunakan untuk menyerap limbah dengan konsentrasi Cu(II sebesar 2984,13 ppm, hasilnya menunjukkan 92,56% ion logam Cu(II teradsorp. Sea sand is abundant natural materials. In addition to be used as a building material, sand can be utilized as heavy metal ion adsorbent, because it has quite a lot of pores, i.e 30% more than its volume. The purpose of this study was to determine the adsorption capacity of Cu(II ions using sea sand alone as control, H2SO4-activated sea sand, Fe2O3-coated sea sand, as well as H2SO4-activated and Fe2O3-coated sea sand. Two kinds of sea sand have been used in the research, i.e the black sand and the white sand. Studies were performed to examine the optimization of the

  12. Magnetic and microstructural properties of (Nd,Pr)-(Tb,Dy,Gd)-(Fe,Co,Al,Cu)-B type magnets

    Energy Technology Data Exchange (ETDEWEB)

    Arinicheva, O. A.; Lileev, A. S. [National University of Science and Technology ' MISIS' (Russian Federation); Reissner, M., E-mail: reissner@ifp.tuwien.ac.at [Vienna University of Technology (Austria); Lukin, A. A. [Ltd. Research and Production Complex ' Magnets and Magnetic Systems' (Russian Federation); Starikova, A. S. [National University of Science and Technology ' MISIS' (Russian Federation)

    2013-04-15

    (Nd,Pr)-(Tb,Dy,Gd)-(Fe,Co,Al,Cu)-B magnets were heat treated in two different ways and investigated in the temperature range 4.2 to 400 K. After optimal heat treatment intrinsic coercive field {sub i}H{sub c} = 1640 and 5040 kA/m for room temperature and 10 K was obtained and the temperature coefficient of remanence {alpha} = -0.01 for temperature range 80 to 375 K was found. On basis of magnetic measurements and {sup 57}Fe Moessbauer spectroscopy, the possible reasons for the increase of {sub i}H{sub c} during multi-step heat treatment are discussed.

  13. On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Anna M. Manzoni

    2016-03-01

    Full Text Available The most commonly investigated high entropy alloy, AlCoCrCuFeNi, has been chosen for optimization of its microstructural and mechanical properties by means of compositional changes and heat treatments. Among the different available optimization paths, the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ′ microstructure like in Ni-based superalloys have been probed and compared. Microscopical observations have been made for every optimization step. Vickers microhardness measurements and/or tensile/compression test have been carried out when the alloy was appropriate. Five derived alloys AlCoCrFeNi, Al23Co15Cr23Cu8Fe15Ni16, Al8Co17Cr17Cu8Fe17Ni33, Al8Co17Cr14Cu8Fe17Ni34.8Mo0.1Ti1W0.1 and Al10Co25Cr8Fe15Ni36Ti6 (all at.% have been compared to the original AlCoCrCuFeNi and the most promising one has been selected for further investigation.

  14. Reduction of CO2 to low carbon alcohols on CuO FCs/Fe2O3 NTs catalyst with photoelectric dual catalytic interfaces.

    Science.gov (United States)

    Li, Peiqiang; Wang, Huying; Xu, Jinfeng; Jing, Hua; Zhang, Jun; Han, Haixiang; Lu, Fusui

    2013-12-01

    In this paper, the CuO FCs/Fe2O3 NTs catalyst was obtained after Fe2O3 nanotubes (Fe2O3 NTs) were decorated with CuO flower clusters (CuO FCs) by the pulse electrochemical deposition method. The in situ vertically aligned Fe2O3 NTs were prepared on the ferrous substrate by a potentiostatic anodization method. The SEM result showed the volcano-like Fe2O3 NTs were arranged in order and the CuO FCs constituted of flaky CuO distributed on the Fe2O3 NTs surface uniformly. After CuO FCs were loaded on Fe2O3 NTs, the absorption of visible light was enhanced noticeably, and its band gap narrowed to 1.78 eV from 2.03 eV. The conduction band and valence band locating at -0.73 eV and 1.05 eV, respectively were further obtained. In the PEC reduction of CO2 process, methanol and ethanol were two major products identified by chromatography. Their contents reached 1.00 mmol L(-1) cm(-2) and 107.38 μmol L(-1) cm(-2) after 6 h, respectively. This high-efficiency catalyst with photoelectric dual catalytic interfaces has a great guidance and reference significance for CO2 reduction to liquid carbon fuels.

  15. Crystalline structure, magnetic and magnetoelastic properties of Nd6Fe13-xCoxCu intermetallic compounds

    Directory of Open Access Journals (Sweden)

    P Iranmanesh

    2011-03-01

    Full Text Available Influence of the partial substitution of Co for Fe on the structural, magnetic and magnetoelastic properties of Nd6Fe13Cu compounds are investigated. Analysis of X-ray diffraction patterns indicates that the multi-phase sample is formed for all samples. Upon Co substitution, the second phase Nd2Fe17, Nd2Fe17-yCoy with 0 < y < 1 and Nd2Fe17-zCoz with 1 < z < 2 is formed in the samples with x = 0, 1, 2, respectively so that the lattice parameters are decreased and the Curie temperature is increased. Due to the ferromagnetic phase Nd2Fe17-yCoy in sample with x = 1, the change of the anisotropy and increase of exchange effects are observed. The effects of long-range magnetic ordering processes on Néel temperature clearly appear in the temperature dependence of the spontaneous magnetostriction. Longitudinal (λl and transverse (λt magnetostrictions are measured to study the magnetoelastic behaviour of these compounds using a strain gauge method. In the low field region, magnetostrictive strains are small and then increase with increasing fields. Strong pining center of Nd atoms that creates large magnetocrystalline anisotropy prevents easy movement of domain walls. In the sample with x = 0, the magnetostriction contribution from the rare earth sublattice (Nd dominates at low temperature and the Fe sublattice contribution becomes increasingly important as temperature rises.

  16. Phase transition from fcc to bcc structure of the Cu-clusters during nanocrystallization of Fe85.2Si1B9P4Cu0.8 soft magnetic alloy

    OpenAIRE

    Masahiko Nishijima; Makoto Matsuura; Kana Takenaka; Akira Takeuchi; Hironori Ofuchi; Akihiro Makino

    2014-01-01

    A role of Cu on the nanocrystallization of an Fe85.2Si1B9P4Cu0.8 alloy was investigated by X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM). The Cu K-edge XAFS results show that local structure around Cu is disordered for the as-quenched sample whereas it changes to fcc-like structure at 613 K. The fcc Cu-clusters are, however, thermodynamically unstable and begin to transform into bcc structure at 638 K. An explicit bcc structure is observed for the sample an...

  17. Separation in liquid and the formation of supersaturated solid solutions in Fe-Cu alloys upon rapid laser melting

    Science.gov (United States)

    Kharanzhevskiy, E. V.

    2016-09-01

    The structure of compacted specimens produced using the rapid laser melting of ultradispersed Fe-50 wt % Cu powders has been studied. The original powder was produced via the mechanical milling of iron and copper powders in a planetary-type ball mill. It has been found that the structure of the compacted specimens produced using rapid laser melting exhibits signs of the initial stages of separation in supercooled liquid. It has been shown using X-ray diffraction analysis as well as scanning and transmission electron microscopy that the final structure contains a supersaturated (Fe; Cu) solid solution formed from the high-speed movement of the solidification front and the nonequilibrium capture of copper by the moving front.

  18. Low-field magnetic properties of amorphous and nanocystalline FeCrCuNbSiB alloys

    International Nuclear Information System (INIS)

    The AC susceptibility dependence on magnetic field, time and temperature of amorphous as well as nanocrystalline Fe73.5-xCrxCu1Nb3Si13.5B9 (x=0-4) alloys was studied. Micromagnetic model is used for calculating the activation energy spectra (AES) of the magnetic after-effect (MAE). It was observed that addition of Cr to the amorphous FeCrCuNbSiB alloys highly decreases the amplitude of the MAE so that no MAE is observed for Cr content higher than 2 at%. After annealing at 550 deg. C, the initial susceptibility increases as a result of magnetic softening during nanocrystallization and the MAE vanishes. The nanocrystalline state was characterized by the high magnetic as well as structural stability. Moreover, addition of 1 at% Cr makes the initial susceptibility of the nanocrytalline sample higher than in the FINEMET alloy

  19. Magnetic Properties of Nanocrystalline Fe{sub x}Cu{sub 1-x} Alloys Prepared by Ball Milling

    Energy Technology Data Exchange (ETDEWEB)

    Yousif, A.; Bouziane, K., E-mail: bouzi@squ.edu.om; Elzain, M. E. [Sultan Qaboos University, Physics Department, College of Science (Oman); Ren, X.; Berry, F. J. [The Open University, Department of Chemistry (United Kingdom); Widatallah, H. M. [Sudan Atomic Energy Commission, Institute of Nuclear Research (Sudan); Al Rawas, A.; Gismelseed, A.; Al-Omari, I. A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

    2004-12-15

    X-ray diffraction, Moessbauer and magnetization measurements were used to study Fe{sub x}Cu{sub 1-x} alloys prepared by ball-milling. The X-ray data show the formation of a nanocrystalline Fe-Cu solid solution. The samples with x{>=}0.8 and x{<=}0.5 exhibit bcc or fcc phase, respectively. Both the bcc and fcc phases are principally ferromagnetic for x{>=}0.2, but the sample with x=0.1 remains paramagnetic down to 78 K. The influence of the local environment on the hyperfine parameters and the local magnetic moment are discussed using calculations based on the discrete-variational method in the local density approximation.

  20. Mechanisms for the Movement of Fe,Mn,Cu and Zn to Plant Roots in Loessal Soil and Lou Soil

    Institute of Scientific and Technical Information of China (English)

    XUMINGGANG; ZHANGYIPING; 等

    1996-01-01

    The pot experiments were conducted in the artificial climate laboratories to determine the relative importance of mass flow and diffusion in supplying ,Fe,Mn,Cu,and Zn to wheat,soybean and maize plants growing in loessal soil and lou soil.It was found that the calculated relative contribution of mass flow of iron,manganese,copper and zinc to plant uptake varied from 5% to more than 100%,depending on the crop species and soil types as well as plant growth stage,soil moisture,atmosphere humidity,etc.The results also showed that the major transportation mechanisms of these micronutrients in soil-root system varied with the crop and its growth,climate and soil,singnificantly,In general,mass flow was more important for Cu and Zn and diffusion was more significant for Fe and Mn at the seedling stage.

  1. Surface tension of liquid ternary Fe-Cu-Mo alloys measured by electromagnetic levitation oscillating drop method.

    Science.gov (United States)

    Wang, H P; Luo, B C; Qin, T; Chang, J; Wei, B

    2008-09-28

    For the liquid Fe-Cu-Mo ternary system, the surface tensions of three selected alloys, i.e., three typical monotectic alloys, were measured by the electromagnetic levitation oscillating drop method over a broad temperature range, including both superheated and undercooled states. The maximum undercooling attained is up to 173 K. The experimental results show a good linear correlation between the surface tension and the temperature. By applying on the Butler equation, the surface tensions were also calculated and they are in good agreement with the measured ones, except that in the undercooled state, the calculated value is slightly larger than the measured results. Interestingly, both the measured and calculated results indicate that the enriched element on the droplet surface is much more conspicuous than other elements in influencing the surface tension. Besides, the viscosity and the density of the liquid Fe-Cu-Mo ternary alloys are also derived on the grounds of the experimentally measured surface tensions. PMID:19045047

  2. Thermodynamic and kinetic study on interfacial reaction and diamond graphitization of Cu-Fe-based diamond composite

    Institute of Scientific and Technical Information of China (English)

    Li Wen-Sheng; Zhang Jie; Dong Hong-Feng; Chu Ke; Wang Shun-Cai; Liu Yi; Li Ya-Ming

    2013-01-01

    Cu-Fe based diamond composites used for saw-blade segments are directly fabricated by vacuum and pressureassisted sintering.The carbide forming elements Cr and Ti are added to improve interfacial bonding between diamond and the Cu-Fe matrix.The interfacial reactions between diamond/graphite and Cr or Ti,and diamond graphitization are investigated by thermodynamics/kinetics analyses and experimental methods.The results show that interfacial reactions and graphitization of diamond can automatically proceed thermodynamically.The Cr3C2,Cr7C3,Cr23C6,and TiC are formed at the interfaces of composites by reactions between diamond and Cr or Ti; diamond graphitization does not occur because of the kinetic difficulty at 1093 K under the pressure of 13 MPa.

  3. Moessbauer study of Cu sub 0 sub . sub 8 Fe sub 2 sub . sub 2 O sub 4

    CERN Document Server

    Kim, S J; An, D H; Kang, K U; Baek, K S; Oak, H N

    2000-01-01

    Cu sub 0 sub . sub 8 Fe sub 2 sub . sub 2 O sub 4 has been studied by using Moessbauer spectroscopy and X-ray diffraction. The crystal is found to have a cubic spinel structure with the lattice constant a sub 0 =8.399 +- 0.005 A. It is noteworthy that a 20% replacement of Cu by Fe in the copper ferrite transforms the crystal structure from tetragonal to cubic and decreases the quadrupole shifts drastically. The iron ions at both A (tetrahedral) and B (octahedral) sites are found to be in ferric states. Atomic migration between A- and B-sites starts near 300 K and increases rapidly with increasing temperature to such a degree that 78% of the ferric ions at the A-sites move over to the B sites at 600 K.

  4. Production of sulfate radical from peroxymonosulfate induced by a magnetically separable CuFe2O4 spinel in water: Efficiency, stability, and mechanism

    KAUST Repository

    Zhang, Tao

    2013-03-19

    A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe2O4 spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe2O4 showed higher activity and 30 times lower Cu2+ leaching (1.5 μg L-1 per 100 mg L-1) than a well-crystallized CuO at the same dosage. CuFe 2O4 maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe2O4 was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe 2O4, the radical production yield from PMS was determined to be near 1 mol/mol. The PMS decomposition involved an inner-sphere complexation with the oxide\\'s surface Cu(II) sites. In situ characterization of the oxide surface with ATR-FTIR and Raman during the PMS decomposition suggested that surface Cu(II)-Cu(III)-Cu(II) redox cycle was responsible for the efficient sulfate radical generation from PMS. © 2013 American Chemical Society.

  5. Effect of Cu on the evolution of precipitation in an Fe-Cr-Ni-Al-Ti maraging steel

    Energy Technology Data Exchange (ETDEWEB)

    Schnitzer, Ronald, E-mail: ronald.schnitzer@unileoben.ac.at [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Schober, Michael [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Zinner, Silvia [Boehler Edelstahl GmbH and Co KG, Mariazeller Strasse 25, A-8605 Kapfenberg (Austria); Leitner, Harald [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)] [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

    2010-06-15

    The evolution of precipitates in an Fe-Cr-Ni-Al-Ti stainless maraging steel alloyed with Cu was investigated during aging at 525 deg. C. Atom probe tomography was used to reveal the development of precipitates and to determine their chemical composition. Two types of precipitates were observed to form during the aging process. Based on their chemical composition these are assumed to be NiAl B2 and Ni{sub 3}(Ti,Al) ({eta}-phase). The two phases of precipitates were found to develop independently of each other and the addition of Cu was found to accelerate precipitation. However, the effect of Cu on the nucleation of these phases is different: on the one hand, in the case of NiAl, Cu is incorporated and thus reduces the activation energy by reducing the lattice misfit; on the other hand, Cu acts as a nucleation site for the precipitation of Ni{sub 3}(Ti,Al) by forming independent Cu clusters.

  6. Highly Efficient Synthesis of Clean Biofuels from Biomass Using FeCuZnAIK Catalyst

    Institute of Scientific and Technical Information of China (English)

    Song-bai Qiu; Yong Xu; Tong-qi Ye; Fei-yan Gong; Zhi Yang; Mitsuo Yamamoto; Yong Liu; Quan-xin Li

    2011-01-01

    Highly efficient synthesis of clean biofuels using the bio-syngas obtained from biomass gasification was performed over Fe1.5Cu1Zn1Al1K0.117 catalyst.The maximum biofuel yield from the bio-syngas reaches about 1.59 kg biofuels/(kgcatal·h) with a contribution of 0.57 kg alcohols/(kgcatal·h) and 1.02 kg liquid hydrocarbons/(kgcatal·h).The alcohol products in the resulting biofuels were dominated by the C2+ alcohols (mainly C2-C6 alcohols) with a content of 73.55%-89.98%.The selectivity of the liquid hydrocarbons (C5+) in the hydrocarbon products ranges from 60.37% to 70.94%.The synthesis biofuels also possess a higher heat value of 40.53-41.49 MJ/kg.The effects of the synthesis conditions,including temperature,pressure,and gas hourly space velocity,on the biofuel synthesis were investigated in detail.The catalyst features were characterized by inductively coupled plasma and atomic emission spectroscopy,X-ray diffraction,temperature programmed reduction,and the N2 adsorption-desorption isotherms measurements.The present biofuel synthesis with a higher biofuel yield and a higher selectivity of liquid hydrocarbons and C2+ alcohols may be a potentially useful route to produce clean biofuels and chemicals from biomass.

  7. Magnetic irreversibility and relaxation in CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Goya, G.F. E-mail: goya@macbeth.if.usp.br; Rechenberg, H.R.; Jiang, J.Z

    2000-08-01

    In this work, we present a study on the magnetic behavior of CuFe{sub 2}O{sub 4} nanoparticles with different particle sizes. Magnetic particle size distribution obtained from M(H) curves in the superparamagnetic (SPM) state showed good agreement with data obtained from X-ray powder diffraction. Field-cooled and zero-field-cooled magnetization data showed a blocking temperature T{sub B}{approx}225 K, independent of particle size, which is associated to interparticle interactions. It was observed that T{sub B} and the irreversibility temperature T{sub irr}, shift to lower temperature with increasing applied fields, both with an H{sup -1} dependence. Strong training effects were observed from relaxation data, assigned to the irreversible behavior of the spin-disordered particle surface. The magnetic viscosity at T=4.2 K was analyzed for sample with D{sub mean}=7.7 nm, revealing strong irreversibility after each major hysteresis loop. These results are discussed in terms of multiple spin-disordered configurations, at particle surface, with quasidegenerate states.

  8. The Use of Al, Cu, and Fe in an Integrated Electrocoagulation-Ozonation Process

    Directory of Open Access Journals (Sweden)

    Carlos E. Barrera Díaz

    2015-01-01

    Full Text Available This study presents the effect of supplying electrochemically generated metallic ions (Al, Cu, and Fe during an ozonation process for treating industrial wastewater. The pollutant removal efficiencies of the electrocoagulation (EC, ozonation, and coupled EC-ozonation processes were examined by the decrease in chemical oxygen demand (COD as a function of treatment time. The EC was performed in a raw industrial wastewater, which has contributions from 39 chemical, 34 metal finishing, 22 textile, 11 leather, and 5 automotive plants, at pH (7.3 using a current density of 150 A/m2 for 60 min, giving a 45% reduction in COD. The ozonation process was more effective with the same wastewater, reducing the COD by 52% after 60 min of treatment. Combining the EC and ozonation methods resulted in a synergistic process that improves the reduction of COD in a shorter time. In just 12 min the integrated process reduced the COD by 88%. Thus, the combination of EC and ozonation processes improves noticeably the wastewater quality, decreasing the treatment time and also reducing the sludge production.

  9. Microstructure Evolution and Rheological Behavior of Cooling Slope Processed Al-Si-Cu-Fe Alloy Slurry

    Science.gov (United States)

    Das, Prosenjit; Samanta, Sudip K.; Bera, Supriya; Dutta, Pradip

    2016-05-01

    In the present work, microstructure evolution during semi-solid slurry generation of Al-Si-Cu-Fe alloy, using a cooling slope, was studied and the effect of microstructural morphology of the slurry on its rheological behavior was investigated. Microstructure evolution during melt flow along the slope was studied by extracting samples from various locations of the slope and performing rapid oil quenching experiments. Quantitative investigation was performed to evaluate primary phase shape and size for different process conditions of the semi-solid slurry, and subsequently rheological investigations were performed to correlate slurry morphology with its flow behavior. Three different types of rheological experiments were performed: isothermal test, shear jump test, and shear time test, in order to investigate rheological behavior of the semi-solid slurry. In addition, effect of melt treatment, by adding modifier (0.1 wt pct of Al-10Sr) and grain refiner (0.15 wt pct of Al-5Ti-1B), on the microstructure evolution during slurry generation, flow behavior of the slurry, and intermetallics formation was studied.

  10. Monte Carlo study of decorated dislocation loops in FeNiMnCu model alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bonny, G., E-mail: gbonny@sckcen.be [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium); Terentyev, D. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium); Zhurkin, E.E. [Saint-Petersburg State Polytechnical University, Experimental Nuclear Physics Department, Institute of Physics, Nanotechnologies and Telecommunications, 29 Polytekhnicheskaya Str., 195251 St. Petersburg (Russian Federation); Malerba, L. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium)

    2014-09-15

    Radiation-induced embrittlement of bainitic steels is the lifetime limiting factor of reactor pressure vessels in existing nuclear light water reactors. The primary mechanism of embrittlement is the obstruction of dislocation motion by nano-metric defects in the bulk of the material due to irradiation. Such features are known to be solute clusters that may be attached to point defect clusters. In this work we study the thermal stability of solute clusters near edge dislocation lines and loops with Burgers vector b = ½[1 1 1] and b = [1 0 0] in FeNiMnCu model alloys by means of Metropolis Monte Carlo simulations. It is concluded that small dislocation loops may indeed act as points for heterogeneous nucleation of solute precipitates in reactor pressure vessel steels and increase their thermodynamic stability up to and above normal reactor operating temperatures. We also found that, in the presence of dislocation-type defects, the Ni content determines the thermodynamic driving force for precipitation, rather than the Mn content.

  11. Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling

    Energy Technology Data Exchange (ETDEWEB)

    Aravinthan, D.; Daniel, M. [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli - 620 024 (India); Sabareesan, P. [Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur - 613 401 (India)

    2015-07-15

    The impact of orange peel coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the switching dynamics of magnetization of the free layer governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The value of the critical current required to initiate the magnetization switching is calculated analytically by solving the LLGS equation and verified the same through numerical analysis. Results of numerical simulation of the LLGS equation using Runge-Kutta fourth order procedure shows that the presence of orange peel coupling between the spacer and the ferromagnetic layers reduces the switching time of the nanopillar device from 67 ps to 48 ps for an applied current density of 4 × 10{sup 12}Am{sup −2}. Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 10{sup 12}Am{sup −2} to 1.39 × 10{sup 12}Am{sup −2}.

  12. Chelation of Cu(II), Zn(II), and Fe(II) by Tannin Constituents of Selected Edible Nuts

    OpenAIRE

    Magdalena Karamać

    2009-01-01

    The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram...

  13. Clustering Effects Under Irradiation in Fe-0.1%Cu Alloy : An Atomic Scale Investigation with the Tomographic Atom Probe

    OpenAIRE

    Pareige, P.; Welzel, S; Auger, P.

    1996-01-01

    In order to understand the effect of displacement cascades on the evolution of the microstructure of ferritic low copper supersaturated materials, analyses by 3D atomic tomography of neutron, electron and self ion irradiated Fe-0.1%Cu, were performed. This alloy was chosen because of its low copper concentration, close to that of french pressure vessel steels. The comparison of the microstructure evolutions in these irradiated specimens reveals the appearance of tiny copper "clusters" or "agg...

  14. Magnetic microstructures from magnetic force microscopy and Monte Carlo simulation in CoFe-Ag-Cu granular films

    OpenAIRE

    Batlle Gelabert, Xavier; Valencia, A.; Labarta, Amílcar; O'Grady, K; Watson, M L

    1998-01-01

    CoFe-Ag-Cu granular films, prepared by rf sputtering, displayed magnetic domain microstructures for ferromagnetic concentrations above about 32% at, and below the percolation threshold. All samples have a fcc structure with an (111) texture perpendicular to the film plane. Magnetic force microscopy (MFM) showed a variety of magnetic domain microstructures, extremely sensitive to the magnetic history of the sample, which arise from the balance of the ferromagnetic exchange, the dipolar interac...

  15. Investigation of the kinetics of internal oxidation of Cu-Fe-alloys with the help of Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Homogeneous and supersaturated Cu Fe mixed crystals are oxidated at an oxygen partial pressure which lies below the decomposition pressure of the copper oxides. With the help of Moessbauer spectroscopy, it is possible to track the kinetics of each iron state during internal oxidation. Corrosion products are magnetite, wuestite, and delafossite. The appearance of these compounds depends on the composition of the mixed crystal, the oxidation temperature and the oxidation time. (orig.)

  16. Cu-Mn-Fe alloys and Mn-rich amphiboles in ancient copper slags from the Jabal Samran area, Saudi Arabia: With synopsis on chemistry of Fe-Mn(III) oxyhydroxides in alteration zones

    Science.gov (United States)

    Surour, Adel A.

    2015-01-01

    In the Jabal Samran area (western Saudi Arabia), secondary copper mineralization in a NE-trending shear zone in which the arc metavolcanic host rocks (dacite-rhyodacite) show conjugate fractures and extensive hydrothermal alteration and bleaching. The zones contain frequent Fe-Mn(III) oxyhydroxides (FeOH-MnOH) that resulted from oxidation of pyrite and Mn-bearing silicates. In the bleached part, the groundmass is represented by Fe-bearing interstratified illite-smectite with up to 4.02 wt% FeOt. FeOH-MnOH are pre-weathering phases formed by hydrothermal alteration in a submarine environment prior to uplifting. Five varieties of FeOH are distinguished, four of them are exclusively hydrothermal with ∼20 wt% H2O whereas the fifth contains ∼31-33 wt% H2O and might represent reworking of earlier hydrothermal FeOH phases by weathering. FeOH fills thin fractures in the form of veinlets and crenulated laminae or as a pseudomorph for pyrite, goethite and finally ferrihydrite, and this oxyhydroxide is characterized by positive correlation of Fe2O3 with SiO2 and Al2O3. On the other hand, MOH shows positive correlation between MnO2 and Al2O3 whereas it is negative between Fe2O3 and SiO2. Paratacamite is the most common secondary copper mineral that fills fractures and post-dates FeOH and MnOH. It is believed that Cl- in the structure of paratacamite represents inherited marine storage rather than from surfacial evaporates or meteoric water. The mineralogy of slags suggests a complicated mineral assemblage that includes native Cu prills, synthetic spinifixed Mn-rich amphiboles with 16.73 wt% MnO, brown glass and Ca-Mn-Fe phase close to the olivine structure. EMPA indicate that the some Cu prills have either grey discontinuous boarder zone of S-rich Mn-Cu alloy (with up to 21.95 wt% S and 19.45 wt% Mn) or grey Cu-Mn-Fe alloy (with up to 15.9 wt% Cu, 39. 12 wt% Mn and 61.64 wt% Fe). Mn in the Cu prills is expelled inward as Cu-Mn-Fe alloy inclusions whereas S is expelled

  17. Effect of annealing treatments on the microwave electromagnetic properties of amorphous FeCuNbSiB microwires

    Institute of Scientific and Technical Information of China (English)

    Liang Di-Fei; Han Man-Gui; Yan Bo; Deng Long-Jiang

    2007-01-01

    The amorphous FeCuNbSiB microwires are fabricated by using the melt extraction method and annealed separately at temperatures T = 573, 673, 723 and 773 K for 1 h. The effect of annealing treatment on the microwave electromagnetic properties of FeCuNbSiB wires/wax composites has been investigated for the first time. It is found that in a frequency range of 0.5-4.0 GHz, the complex permittivity, permeability, magnetic and electric loss tangents of FeCuNbSiB wires/wax composites are strongly dependent on the annealing temperature and frequency. For T = 573,723 and 773K, two resonance peaks are found at frequency f = 1.2 and 3.3GHz. However, for T = 673K, only one resonance peak occurs at f = 3.3 GHz. The resonance peak at f = 1.2 GHz is believed to be due to the stress-induced anisotropy, while the resonance peak at f = 3.3 GHz is attributed to the random anisotropy.

  18. In-situ Lorentz microscopy of Fe85Si2B8P4Cu1 nanocrystalline soft magnetic alloys

    International Nuclear Information System (INIS)

    Microstructure dependence of magnetic properties of soft magnetic Fe–Si–B–P–Cu nanocrystalline alloys were studied by using in-situ Lorentz microscopy in a transmission electron microscope equipped with a magnetizing system. In particular, we investigated in detail motion of magnetic domain walls in heat-treated Fe85Si12B6P4Cu1 amorphous ribbons. Smooth motion of domain walls was observed for the optimally heat-treated (at 430 °C) nano-crystalline alloy. Pinning of domain walls was observed for higher-temperature-heat-treated (470 °C) ribbons. Both ribbons showed a nanocrystalline structure containing α-Fe crystallites of about 15 nm in size. Electron diffraction patterns indicated that the higher-temperature-heat-treated samples contained boride precipitates, which is considered to cause less smooth domain wall motion. - Highlights: • Magnetic properties of newly developed Fe–Si–B–P–Cu nanocrystalline alloys are analyzed by TEM. • Motion of magnetic domain walls were visualized by in-situ Lorentz microscopy. • Borides (Fe2B) in heat-treated specimen cause reduction in domain wall motion smoothness

  19. Functionalized graphene oxide quantum dot-PVA hydrogel: a colorimetric sensor for Fe2+, Co2+ and Cu2+ ions

    Science.gov (United States)

    Baruah, Upama; Chowdhury, Devasish

    2016-04-01

    Functionalized graphene oxide quantum dots (GOQDs)-poly(vinyl alcohol) (PVA) hybrid hydrogels were prepared using a simple, facile and cost-effective strategy. GOQDs bearing different surface functional groups were introduced as the cross-linking agent into the PVA matrix thereby resulting in gelation. The four different types of hybrid hydrogels were prepared using graphene oxide, reduced graphene oxide, ester functionalized graphene oxide and amine functionalized GOQDs as cross-linking agents. It was observed that the hybrid hydrogel prepared with amine functionalized GOQDs was the most stable. The potential applicability of using this solid sensing platform has been subsequently explored in an easy, simple, effective and sensitive method for optical detection of M2+ (Fe2+, Co2+ and Cu2+) in aqueous media involving colorimetric detection. Amine functionalized GOQDs-PVA hybrid hydrogel when put into the corresponding solution of Fe2+, Co2+ and Cu2+ renders brown, orange and blue coloration respectively of the solution detecting the presence of Fe2+, Co2+ and Cu2+ ions in the solution. The minimum detection limit observed was 1 × 10-7 M using UV-visible spectroscopy. Further, the applicability of the sensing material was also tested for a mixture of co-existing ions in solution to demonstrate the practical applicability of the system. Insight into the probable mechanistic pathway involved in the detection process is also being discussed.

  20. Application of Fe-Cu binary oxide nanoparticles for the removal of hexavalent chromium from aqueous solution.

    Science.gov (United States)

    Khan, Saif Ullah; Zaidi, Rumman; Hassan, Saeikh Z; Farooqi, I H; Azam, Ameer

    2016-01-01

    The adsorption process has been used as an effective technique for the removal of metal ions from aqueous solutions. Groundwater remediation by nanoparticles has received interest in recent years. In the present study, a binary metal oxide of Fe-Cu was prepared and used for the removal of hexavalent chromium from aqueous solution. Batch experiments were performed to investigate the effects of initial Cr (VI) concentration, dose of adsorbent, and pH of solution on the removal efficiency of Cr (VI). The prepared nanostructured Fe-Cu binary oxides were able to reduce the concentration of Cr (VI) in aqueous solution. Binary metal oxides nanoparticle exhibited an outstanding ability to remove Cr (VI) due to high surface area, low particle size, and high inherent activity. The percentage removal efficiency of Cr (VI) increased with nanoparticles doses (0.1 g L(-1)-2.5 g L(-1)), whereas it decreased with initial Cr (VI) concentration (1 mg L(-1)-25 mg L(-1)) and with pH (3-9). The Freundlich model was found to be the better fit for adsorption isotherm. The prepared nanomaterial was characterized using powder X-ray diffraction, scanning electron microscopy (SEM), and ultraviolet (UV)-visible spectroscopy. It showed that the Fe-Cu binary oxides were formed in single phase. SEM micrograph showed aggregates with many nano-sized particles. UV-visible spectroscopy showed quantum confinement effect. PMID:27386994

  1. Electronic Structure and Thermoelectric Properties of the Delafossite-Type Oxides CuFe1- x Ni x O2

    Science.gov (United States)

    Nozaki, T.; Hayashi, K.; Kajitani, T.

    2009-07-01

    In this study, we investigated the chemical composition and electronic structure of the delafossite-type oxides CuFeO2 (CFO) and CuFe0.98Ni0.02O2 (CFNO). The hole carrier density in the Cu and FeO2 layers of CFNO was found to be different from that of CFO, leading to the enhancement of electrical conductivity by Ni substitution. In addition, thermoelectric properties were found to be affected by the surface treatment, possibly due to some surface contamination. An etched CFNO (E-CFNO) exhibited a higher electrical conductivity and a higher Seebeck coefficient relative to the polished CFNO (P-CFNO). The thermal conductivity did not change much between E-CFNO and P-CFNO. As a result, the thermoelectric performance of E-CFNO was higher than that of P-CFNO. This result indicates that etching is needed when we use CFNO as a p-leg in thermoelectric generators.

  2. Nitrite to nitric oxide interconversion by heme FeII complex assisted by [CuI(tmpa)]+

    KAUST Repository

    Turias, Francesc

    2015-09-09

    The present computational study complements the recent experimental efforts by Karlin and coworkers to describe the interconversion of nitrite to nitric oxide by means of an iron porphyrin complex together with a Cu chemical system, i.e., the iron(II) complex (F8TPP)FeII [F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2−)] and a preformed copper(II)–nitrito complex [(tmpa)CuII(NO2)][B(C6F5)4] [tmpa = tris(2-pyridylmethyl)amine], being the latter an oxidized species of [(tmpa)CuI(MeCN)]+. By DFT calculations, we unravel how the reduction of nitrite to nitric oxide takes place through a μ-oxo heme-FeIII–O–CuII complex, following a mimetic path as in the cytochrome c oxidase. Mayer bond order (MBO) and energy decomposition analyses are used to analyze the bonding strength of such nitro derivatives to either copper or iron. © 2015 Springer Science+Business Media New York

  3. Thermodynamic analysis of the simple microstructure of AlCrFeNiCu high-entropy alloy with multi-principal elements

    Institute of Scientific and Technical Information of China (English)

    Aumin LI; Xiyan ZHANG

    2009-01-01

    AlCrFeNiCu high-entropy alloy (THA) was synthesized by the arc melting and casting method. The alloy exhibits simple FCC and BCC solid solution phases rather than intermetallic compounds. The reason is that the Gibbs free energy of mixing of the equimolar A1CrFeNiCu alloy is smaller than that of inter-metallic compounds by calculation according to the Miedema model.

  4. Electrochemical deposition and microstructural characterization of AlCrFeMnNi and AlCrCuFeMnNi high entropy alloy thin films

    Science.gov (United States)

    Soare, V.; Burada, M.; Constantin, I.; Mitrică, D.; Bădiliţă, V.; Caragea, A.; Târcolea, M.

    2015-12-01

    Al-Cr-Fe-Mn-Ni and Al-Cr-Cu-Fe-Mn-Ni high entropy alloy thin films were prepared by potentiostatic electrodeposition and the microstructure of the deposits was investigated. The thin films were co-deposited in an electrolyte based on a DMF (N,N-dimethylformamide)-CH3CN (acetonitrile) organic compound. The energy dispersive spectrometry investigation (EDS) indicated that all the five respectively six elements were successfully co-deposited. The scanning electron microscopy (SEM) analysis revealed that the film consists of compact and uniform particles with particle sizes of 500 nm to 4 μm. The X-ray diffractometry (XRD) patterns indicated that the as-deposited thin films were amorphous. Body-centered-cubic (BCC) structures were identified by XRD after the films were annealed at various temperatures under inert Ar atmosphere. The alloys adhesion on the substrate was determined by the scratch-testing method, with higher values obtained for the Al-Cr-Cu-Fe-Mn-Ni alloy.

  5. Re-Os molybdenite and Ar-Ar phlogopite dating of Cu-Fe-Au-Mo (W) deposits in southeastern Hubei, China

    Science.gov (United States)

    Xie, G.-Q.; Mao, J.-W.; Li, R.-L.; Qü, W.-J.; Pirajno, F.; Du, A.-D.

    2007-07-01

    The Cu-Fe-Au-Mo (W) deposits in southeastern Hubei are an important component of the Middle-Lower Yangtze River metallogenic belt. Molybdenite from the Fengshandong Cu- (Mo), Ruanjiawan W-Cu- (Mo), Qianjiawan Cu-Au, Tongshankou Cu-Mo and Tonglüshan Cu- (Fe) deposits yielded Re-Os ages of 144.0 ± 2.1 Ma, 143.6 ± 1.7 Ma, 137.7 ± 1.7 Ma, 142.3 ± 1.8-143.7 ± 1.8 Ma and 137.8 ± 1.7-138.1 ± 1.8 Ma, respectively. Phlogopite from the Tieshan Fe- (Cu) deposit yielded an Ar-Ar age of 140.9 ± 1.2 Ma. These data and other published isotopic ages (Re-Os molybdenite and Ar-Ar mica ages) for the Cu-Fe-Au-Mo (W) deposits in the Middle-Lower Yangtze River metallogenic belt show that Cu-Fe-Au-Mo (W) mineralisation in the Tongling, Anqing, Jiurui and Edong ore districts developed in a narrow time span between 135.5 and 144.9 Ma, reflecting an important regional metallogenic event. An integrated study of available petrological and geochronological data, together with relationships to magmatism and the regional geodynamic framework, indicate that the Cu-Fe-Au-Mo (W) mineralisation in the Middle-Lower Yangtze River belt occurred during a regime of lithospheric extension. This extension is probably related to Late Mesozoic processes of lower crustal delamination and lithospheric thinning in East China.

  6. Effect of Heat Treatment on Morphology of Fe-Rich Intermetallics in Hypereutectic Al-Si-Cu-Ni Alloy with 1.26 pct Fe

    Science.gov (United States)

    Sha, Meng; Wu, Shusen; Wan, Li; Lü, Shulin

    2013-12-01

    Cobalt is generally considered as the element that can neutralize the negative effects of iron in Al alloys, such as inducing fracture and failure for stress concentration. Nevertheless, Fe-rich intermetallics would be inclined to form coarse plate-like δ-Al4(Fe, Co, Ni)Si2 particles when the content of Fe was high, which could also cause inferior mechanical properties. The dissolution and transformation of δ-Al4(Fe, Co, Ni)Si2 phase in solution heat-treated samples of Al-20Si-1.85Cu-1.05Ni-1.26Fe-1.35Co alloy were studied using optical microscopy, image analysis, and scanning electron microscopy. The effects of solution heat treatment time ranging from 0 to 9 hours at 783.15 K (510 °C) on mechanical properties were also investigated. The coarse plate-like δ-Al4(Fe, Co, Ni)Si2 particles varied slowly through concurrent dissolution along widths and at the plate tips as solution treatment time increased, which could be explained from diffusion-induced grain boundary migration. Solution heat treatment also has an important influence on mechanical properties. The maximum ultimate tensile strength and yield strength after T6 treatment were 258 and 132 MPa, respectively, while the maximum hardness was 131 HB. Compared with those of the samples in the as-cast state, they increased by 53, 42, and 28 pct, respectively. Moreover, δ-Al4(Fe, Co, Ni)Si2 phase, which appears as a coarse plate-like particle in two dimensions, is actually a cuboid in three dimensions. The length of this cuboid is close to the width, while the height is much smaller.

  7. The Gibbs free energy of nukundamite (Cu3.38Fe0.62S4): A correction and implications for phase equilibria

    Science.gov (United States)

    Seal, R.R., II; Inan, E.E.; Hemingway, B.S.

    2001-01-01

    The Gibbs free energy of formation of nukundamite (Cu3.38Fe0.62S4) was calculated from published experimental studies of the reaction 3.25 Cu3.38Fe0.62S4 + S2 = 11 CuS + 2 FeS2 in order to correct an erroneous expression in the published record. The correct expression describing the Gibbs free energy of formation (kJ???mol-1) of nukundamite relative to the elements and ideal S2 gas is ??fG?? nukundamite T(K) = -549.75 + 0.23242 T + 3.1284 T0.5, with an uncertainty of 0.6%. An evaluation of the phase equilibria of nukundamite with associated phases in the system Cu-Fe-S as a function of temperature and sulfur fugacity indicates that nukundamite is stable from 224 to 501??C at high sulfidation states. At its greatest extent, at 434??C, the stability field of nukundamite is only 0.4 log f(S2) units wide, which explains its rarity. Equilibria between nukundamite and bornite, which limit the stability of both phases, involve bornite compositions that deviate significantly from stoichiometric Cu5FeS4. Under equilibrium conditions in the system Cu-Fe-S, nukundamite + chalcopyrite is not a stable assemblage at any temperature.

  8. Mechanically strong nanocrystalline Fe-Si-B-P-Cu soft magnetic powder cores utilizing magnetic metallic glass as a binder

    Science.gov (United States)

    Luan, Jian; Sharma, Parmanand; Yodoshi, Noriharu; Zhang, Yan; Makino, Akihiro

    2016-05-01

    We report on the fabrication and properties of soft magnetic powder cores with superior mechanical strength as well as low core loss (W). Development of such cores is important for applications in automobiles/devices operating in motion. High saturation magnetic flux density (Bs) Fe-Si-B-P-Cu powder was sintered with Fe55C10B5P10Ni15Mo5 metallic glass (MG) powder in its supercooled liquid state by spark plasma sintering. The sintered cores are made from the nanocrystalline powder particles of Fe-Si-B-P-Cu alloy, which are separated through a magnetic Fe55C10B5P10Ni15Mo5 MG alloy. Low W of ˜ 2.2 W/kg (at 1T and 50 Hz), and high fracture strength (yielding stress ˜500 MPa), which is an order of magnitude higher than the conventional powder cores, were obtained. Stronger metal-metal bonding and magnetic nature of MG binder (which is very different than the conventional polymer based binders) are responsible for the superior mechanical and magnetic properties. The MG binder not only helps in improving the mechanical properties but it also enhances the overall Bs of the core.

  9. Thermal stability of the induced magnetic anisotropy and structure of the nanocrystalline alloy FeCuNbSiB

    International Nuclear Information System (INIS)

    The magnetic anisotropy induced in the ribbons of the Fe73.5Cu1Nb3Si13.5B9 alloy in the course of stress annealing combined with the nanocrystallising one was investigated. Crystalline phases formed during the above treatments were studied by the Moessbauer method. Analysis of the Moessbauer results showed that the content of the Fe-Si phases depends neither on the exposure time nor on the value of the induced magnetic anisotropy constant. At the same time, in the regions containing, along with Fe, Nb and B the process of redistributing the elements proceeds with time, and the deeper the process, the higher the thermal stability of the induced magnetic anisotropy

  10. Structural and soft magnetic properties of Fe73.5Nb3M1Si13.5B9 (M=Cu, Mn, Pt)

    International Nuclear Information System (INIS)

    The magnetic and the structural properties have been investigated for Fe73.5Nb3M1Si13.5B9 (M=Cu, Mn, Pt) alloys in their as-received and heat-treated state. Differential scanning calorimeter and scanning electrical resistivity were used to study crystallization behaviour and to examine the influence of the nucleation elements Cu, Mn and Pt on the structural and magnetic properties of Fe-based nanocrystalline materials. The temperature coefficient of resistivity above Curie temperature was found to be very low (0.2x10-4 K-1) in the Cu containing alloy as compared to the alloys which contained Mn or Pt. A broad exothermic DSC peak for the formation of Fe3Si nanoparticles was absent when Cu was replaced by Mn or Pt. Instead, a sharp exothermic peak for the formation of Fe3(SiB) phase was observed with an onset at 875 K. The magnetic properties of the three alloys measured after stress relaxed annealing were similar. However, after first-stage crystallization, the soft magnetic properties were further enhanced only in Cu containing alloys due to the formation of Fe3Si nanoparticles. Such nanoparticles together with different intermetallic phases like FeMn3 or FePt3 were formed in Mn or Pt containing alloys. Moreover, the NbFeSi phase was also formed in the latter alloys after higher temperature annealing which reduced not only the amount of the Fe3Si phase but also the grain refining effect due to the lesser amount of Nb available at the grain boundary. When Cu was replaced by Mn or Pt, the formation of different intermetallics reduced the volume fraction of Fe3Si nanoparticles and the lesser amount of grain refining Nb made the materials magnetically inferior after annealing above 775 K

  11. Experimental and theoretical study of the oxidation of ventilation air methane over Fe2O3 and CuO.

    Science.gov (United States)

    Jin, Yonggang; Sun, Chenghua; Su, Shi

    2015-07-01

    Coal mine ventilation air methane (VAM) is an important contributor to methane emissions from the energy sector. Although various technologies are under development, treatment of the VAM with an efficient and cost-effective approach has been an ongoing challenge due to massive flow rates of the ventilation air and low and variable methane concentrations. Recently a new concept based on the principle of chemical looping combustion (CLC) has been proposed for VAM abatement (Appl. Energy, 2014, 113, 1916), in which oxidation of low-concentration CH4 balanced by N2 with Fe2O3 or CuO as the oxygen carrier was studied. Here, we thoroughly examined the feasibility of CLC of VAM based on experimental study and theoretical calculations. Reduction of Fe2O3 and CuO and evolution of gas products during CH4 oxidation were investigated using TGA-MS under two reaction atmospheres: 1 vol% CH4 balanced by N2 and the simulated VAM containing 1 vol% CH4, 20 vol% O2, 0.4 vol% CO2 and balance N2. It was found that the CLC of VAM is fundamentally infeasible because the reduced phase of Fe2O3 and CuO cannot be formed for chemical looping when reacting with the simulated VAM containing abundant oxygen. Theoretical calculations revealed that Fe2O3 and CuO remain stable without the transition to the reduced phase as the generated oxygen vacancy on the surface of metal oxides during CH4 oxidation can recover quickly with O2 adsorption and dissociation. Calculations confirmed that both Fe2O3 and CuO play a role of surface catalyst in VAM oxidation. More importantly, it was found that the low-coordinated metal atoms and oxygen vacancies can stabilize CHx radicals to promote the dissociation of CH4, which is generally the rate-determining step for CH4 oxidation. Such findings are useful for new development and understanding of high-performance and low-cost metal oxide catalysts for CH4 oxidation. PMID:26028316

  12. 草酸根桥联的Cu(Ⅱ)-Fe(Ⅲ)-Cu(Ⅱ)异三核配合物的合成及生物活性%Synthesis of Cu ( Ⅱ )-Fe ( Ⅲ )-Cu ( Ⅱ )Heterotrinuclear Complexes through Oxalato Bridge and their Biological Activity

    Institute of Scientific and Technical Information of China (English)

    景志红; 李延团

    2001-01-01

    合成了四种新的草酸根桥联的异三核配合物[Cu2Fe(C2O4)3L2](NO3)(L=phen,Mephen,Me2phen,NO2phen)。经元素分析,摩尔电导和红外光谱及电子光谱表征了这些配合物的组成和结构,并研究了四种配合物的杀菌活性。%Four new heterotrinuclear complexes through oxalato bridge have been synthesized, namely [Cu2Fe (C2O4)3L2] (NO3) (L = phen, Mephen, Me2phen, NO2phen). Their structures were characterized by elemental analysis, molar conductance, IR and electronic spectra. Antibacterial activities of these complexes were tested.

  13. Effect of Silicon on Hot Shortness in Fe-Cu-Ni-Sn-Si Alloys During Isothermal Oxidation in Air

    Science.gov (United States)

    Sampson, Erica; Sridhar, Seetharaman

    2013-10-01

    Residual Cu in scrap-based EAF steel leads to a surface-cracking phenomenon known as surface hot shortness. Si is known to provide a potential reduction in hot shortness; however, the mechanisms involved are not fully understood for low Si quantities. The current study aims to determine a window of Si contents with a given Ni content needed to counteract the negative effects of Sn and Cu to reduce hot shortness and to determine the mechanism. Thermogravimetric analysis (TG), SEM-EDS, XRD, and TEM were used to study the hot shortness behavior of Fe containing 0.2 pct Cu, 0.05 pct Ni, 0.01 pct Sn and with varying Si-content (0.02 pct, 0.1 pct, 0.15 pct, and 0.2 pct Si). It was found that the fayalite formation resulting in a reduction of oxidation and consequently liquid Cu formation occurred for all Si contents examined. The range of Si contents between 0.1 and 0.2 wt pct Si exhibited a mechanism that was a combination of fayalite formation impeding oxidation as well as occlusion of the Cu-rich liquid. This range was acceptable to alleviate hot shortness.

  14. Microstructure and mechanical properties of spray-deposited Al-Si-Fe-Cu-Mg alloy containing Mn

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Al-20Si-5Fe-3Cu-lMg alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the spray deposited hypereutectic Al-Si alloy were studied using optical microscopy, scanning electron microscopy, X-ray diffraction, TEM (Transmission Electron Microscope) and HREM (High-resolution Electron Microscope), DSC (Differential Scanning Calorimetry), microhardness measurement, and tensile tests. The effects of Mn on the microstructural evolution of the highsilicon aluminum alloy after extrusion and heat treatment have been examined. The results show that two kinds of phases, i.e. S (Al2CuMg) and σ(Al5Cu6Mg2), precipitated from matrix and improved the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃). The tensile test results indicate that the spray-deposited Al-20Si-SFe-3Cu-1Mg alloy has better strength than the powder metallurgy processed Al-20Si-3Cu-1Mg alloy at elevated temperature.

  15. Optimization of planar Hall effect sensor for magnetic bead detection using spin-valve NiFe/Cu/NiFe/IrMn structures

    Energy Technology Data Exchange (ETDEWEB)

    Bui Dinh Tu; Do Thi Huong Giang; Tran Mau Danh; Nguyen Huu Duc [Department of Nano Magnetic Materials and Devices, Faculty of Engineering Physics, College of Technology, Vietnam National University, Hanoi (Viet Nam); Le Viet Cuong [Laboratory for Micro-Nano Technology, College of Technology, Vietnam National University, Hanoi (Viet Nam)], E-mail: buidinhtu@vnu.edu.vn

    2009-09-01

    Present paper deals with the planar Hall effect (PHE) of Ta(5 nm)/NiFe(t{sub f})/Cu(1.2 nm)/NiFe(t{sub p})/IrMn(15 nm)/Ta(5 nm) spin-valve structures. Experimental investigations are performed for 50 x 50 {mu}m{sup 2} junctions with various thicknesses of free and pinned layer t{sub f} = 4, 8, 10, 15, 20 nm and t{sub p} = 2, 3, 6, 8, 9, 12 nm. The results show that the thicker free layers, the higher PHE signal is obtained. In addition, the thicker pinned layers, the lower PHE signal. The highest PHE sensitivity S of 15.6 m{omega}/Oe is obtained in the spin-valve configuration with t{sub f} = 20 nm and t{sub p} = 2 nm. This optimum structure is rather promising for micro magnetic bead detections.

  16. Optimization of planar Hall effect sensor for magnetic bead detection using spin-valve NiFe/Cu/NiFe/IrMn structures

    Science.gov (United States)

    Tu, Bui Dinh; Viet Cuong, Le; Thi Huong Giang, Do; Mau Danh, Tran; Duc, Nguyen Huu

    2009-09-01

    Present paper deals with the planar Hall effect (PHE) of Ta(5 nm)/NiFe(tf)/Cu(1.2 nm)/NiFe(tp)/IrMn(15 nm)/Ta(5 nm) spin-valve structures. Experimental investigations are performed for 50 × 50 μm2 junctions with various thicknesses of free and pinned layer tf = 4, 8, 10, 15, 20 nm and tp = 2, 3, 6, 8, 9, 12 nm. The results show that the thicker free layers, the higher PHE signal is obtained. In addition, the thicker pinned layers, the lower PHE signal. The highest PHE sensitivity S of 15.6 mΩ/Oe is obtained in the spin-valve configuration with tf = 20 nm and tp = 2 nm. This optimum structure is rather promising for micro magnetic bead detections.

  17. Evaluation of Antioxidant and Cytotoxicity Activities of Copper Ferrite (CuFe2O4 and Zinc Ferrite (ZnFe2O4 Nanoparticles Synthesized by Sol-Gel Self-Combustion Method

    Directory of Open Access Journals (Sweden)

    Samikannu Kanagesan

    2016-08-01

    Full Text Available Spinel copper ferrite (CuFe2O4 and zinc ferrite (ZnFe2O4 nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe2O4 and 68 nm for ZnFe2O4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug−1 for copper ferrite (50.63 Am2/Kg and 28.8 Am2/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH free radicals. ZnFe2O4 and CuFe2O4 nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL of ZnFe2O4 and CuFe2O4 with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

  18. Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

    International Nuclear Information System (INIS)

    We apply a novel atomistic kinetic Monte Carlo model, which includes local chemistry and relaxation effects when assessing the migration energy barriers of point defects, to the study of the microchemical evolution driven by vacancy diffusion in FeCu and FeCuNi alloys. These alloys are of importance for nuclear applications because Cu precipitation, enhanced by the presence of Ni, is one of the main causes of hardening and embrittlement in reactor pressure vessel steels used in existing nuclear power plants. Local chemistry and relaxation effects are introduced using artificial intelligence techniques, namely a conveniently trained artificial neural network, to calculate the migration energy barriers of vacancies as functions of the local atomic configuration. We prove, through a number of results, that the use of the neural network is fully equivalent to calculating the migration energy barriers on-the-fly, using computationally expensive methods such as nudged elastic bands with an interatomic potential. The use of the neural network makes the computational cost affordable, so that simulations of the same type as those hitherto carried out using heuristic formulas for the assessment of the energy barriers can now be performed, at the same computational cost, using more rigorously calculated barriers. This method opens the way to properly treating more complex problems, such as the case of self-interstitial cluster formation, in an atomistic kinetic Monte Carlo framework.

  19. Transmission Mössbauer spectroscopy and x-ray diffraction studies on the structure of nanocrystalline Fe-Cu-Si-B alloys

    Science.gov (United States)

    Liu, X. D.; Lu, K.; Hu, Z. Q.; Ding, B. Z.; Zhu, J.; Jiang, J.

    1994-04-01

    Nanocrystalline Fe-Cu-Si-B alloys with grain sizes of 25-90 nm were synthesized by crystallization of the amorphous alloy. Two nanocrystalline phases of α-Fe(Si) and Fe2B were observed in all tested samples. Transmission Mössbauer spectroscopy investigation on the structure of nanocrystalline Fe-Cu-Si-B alloys showed that Si atoms are completely and substitutionally dissolved in Fe bcc lattice and the arrangement of the Si atoms in the α-Fe(Si) phase shows short range order (SRO), whereas 8.5-9.7 at. % of the B atoms were found as Fe2B and the remainder were located in the interfaces. When grains grow larger, the arrangement of the Si atoms in the α-Fe(Si) phase changes. Interestingly, x-ray diffraction results reveal that the lattice constant of α-Fe(Si) phase decreases rapidly with grain coarsening. Based on the thermodynamic analysis, the changes in the lattice constant of the α-Fe(Si) phase and SRO of Si atoms in bcc Fe lattices were attributed to the lattice expansion as a result of the variation of vacancy concentration in α-Fe(Si) solid solution. Meanwhile, owing to the interface contribution, the alloy with small grain size is found to exhibit large values of half linewidth (HLW) and isomer shift (IS) in the Mössbauer spectra. The results from electrical resistivity measurements agree and confirm the strong effects of the lattice distortion and interfaces.

  20. High pressure high temperature (HPHT) synthesis and physical characterization of FeSr{sub 2}EuCu{sub 2}O{sub 8-{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Ubaldini, A. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)], E-mail: alberto.ubaldini@nims.go.jp; Awana, V.P.S. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110 012 (India); Balamurugan, S.; Takayama-Muromachi, E. [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2007-09-01

    FeSr{sub 2}EuCu{sub 2}O{sub 8} (FeEu-1212) does not exhibit superconductivity when prepared by classical solid state route, because of iron atoms substitute partially copper atoms in the superconductive CuO{sub 2} planes. Recently, it has been found that high temperature annealing in Ar or N{sub 2} can favour the complete substitution of copper in CuO{sub 1-{delta}} chains instead of in the CuO{sub 2} planes. After this annealing, the total oxygen content of the tetragonal FeSr{sub 2}RECu{sub 2}O{sub 8} decreases and the crystal structure changes to orthorhombic. It is possible to get superconductivity with a second annealing in O{sub 2} at low temperature. In this work a different approach was tried for first time. The samples of FeSr{sub 2}EuCu{sub 2}O{sub 8-{delta}} series with {delta} = 0, 0.5, 0.75 and 1 were prepared by high pressure high temperature (HPHT) synthesis starting from a mixture of Fe{sub 2}O{sub 3}, SrO{sub 2}, Eu{sub 2}O{sub 3}, CuO and Cu. The final oxygen content was determined by the ratio between CuO and Cu. The structure of thus prepared samples changed from tetragonal for {delta} = 0 to orthorhombic for {delta} = 0.75 and 1. The iron atoms selectively occupy the CuO{sub 1-{delta}} chains, if the oxygen content is low. Superconductive properties of these materials were studied, by subjecting them to high pressure and low temperature annealing with Ag{sub 2}O{sub 2} or KClO{sub 4} as oxidizing agents.

  1. Magnetically separable Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposites: Preparation, characterization and visible-light photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chunhua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@whu.edu.cn [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Cao, Qihua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China)

    2015-04-01

    Highlights: • A novel magnetically-separable Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} photocatalyst was in situ prepared. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs had rough and porous chitosan surface layer embedded with Fe{sub 3}O{sub 4} NPs. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed large surface areas and special dimodal pore structure. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed superparamagnetism and could be easily magnetic separated. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited good visible-light photocatalytic activity and stability. - Abstract: A novel magnetically-separable visible-light-induced photocatalyst, Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposite (Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu{sub 2}O was wrapped in chitosan matrix embedded with Fe{sub 3}O{sub 4} nanoparticles. The tight combination of magnetic Fe{sub 3}O{sub 4} and semiconductor Cu{sub 2}O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B

  2. Effect of annealing on VmHn complexes in hydrogen ion irradiated Fe and Fe–0.3%Cu alloys

    International Nuclear Information System (INIS)

    Graphical abstract: The effect of annealing on VmHn complexes in irradiated Fe–0.3%Cu alloy was investigated using positron annihilation spectroscopy based on a slow positron beam. The formation of vacancy-type defects due to the 0.1 dpa irradiation would lead to the increment of the S parameter compared to the unirradiated specimen. A larger number of hydrogen deposited at the damage area and hydrogen atoms (Hn) occupied vacancy sites (Vm), which could lead to the formation of numerous VmHn complexes. The irradiated sample was annealed isochronally for 30 min at 150 °C, 200 °C, 300 °C, 400 °C and 500 °C, respectively. An evident defect peak formed at 150 °C, which meant the VmHn complexes were broken and a larger of hydrogen atoms was escaping. The remaining vacancy-type defect induced the increment of the S parameter. The peaks migrated from the damage area towards to surface region (peaks 1–5). The S parameters in the damage area gradually decreased with the increasing annealing temperature. The shrinkage of vacancy-type defects and the density of defects induced the decrease of S parameters during elevated annealing treatment. - Highlights: • VmHn complexes formed in H+ irradiated Fe and Fe–0.3%Cu alloys. • S–W results confirmed the formation of Cu precipitates in irradiated Fe–0.3%Cu. • VmHn complexes were broken and H atoms were escaping after annealing treatment. • S peaks would migrate towards to surface with the annealing temperature. - Abstract: The effect of annealing on VmHn complexes and Cu precipitate behaviours in hydrogen ion irradiated Fe and Fe–0.3%Cu alloys was investigated by positron annihilation spectroscopy using a slow positron beam. The results of S parameters indicated that the room temperature irradiation was benefit for the formation of the VmHn complex compared to the elevated temperature irradiation. The S–W results confirmed the formation of Cu precipitates in Fe–0.3%Cu even at the irradiation dose of 0

  3. Mineralogy and trace element geochemistry of the Co- and Cu-bearing sulfides from the Shilu Fe-Co-Cu ore district in Hainan Province of South China

    Science.gov (United States)

    Wang, Zhilin; Xu, Deru; Zhang, Zhaochong; Zou, Fenghui; Wang, Li; Yu, Liangliang; Hu, Mingyue

    2015-12-01

    Hosted within the metamorphosed, neritic siliciclastic rocks and sedimentary carbonates of the Proterozoic Shilu Group, the Shilu Fe-Co-Cu ore district in Hainan Province of South China comprises the upper Fe- and the lower Co-Cu ore layers. Combined with the field observation, the mineralogical and geochemical studies of sulfides using electron microprobe and laser ablation ICP-MS analyses recognized three types of Co-Cu ores. Type I is represented by massive ores and mainly comprises the first generation of pyrite (PyI) which occurred either as recrystallized, subhedral to euhedral microcrystal aggregates (PyIa) or as elongated, fine-grained euhedral grains (PyIb) with an orientated alignment parallel to S1 foliation. Type II is banded, disseminated and brecciated ores, and composed of the second generation of pyrite (PyII) which displays internal rhythmic growth zoning, the first generations of chalcopyrite (CcpI) and pyrrhotite (PoI), and associated Co-(Ni)-(As)-sulfide minerals. Type III occurring as veins or veinlets mainly consists of the third generation of pyrite (PyIII) and the second generations of chalcopyrite (CcpII) and pyrrhotite (PoII), of which PyIII appears as subhedral to euhedrall grains or as rims of composite pyrite. The moderate Co and As, and high Ni contents as well as the low Co/Ni ratios (∼2-5) in PyI indicate a sedimentary-metamorphic origin for Type I ores. The higher Co, Ni and As concentrations in PyIb relative to PyIa likely was related to an inhomogeneous deformation-metamorphism. The highest Co (av. 51,195 ppm) in PyII and Ni (av. 3374 ppm) in PoI most likely were linked to the preferred incorporation of Co into pyrite and Ni into pyrrhotite. Combined with the high Ag concentrations in CcpI (av. 266 ppm) and PyII (av. 13.32 ppm), the high Co/Ni ratios in PyII (av. 1241) suggest the derivation of Type II ores from a Co-Cu-Ni-Ag-rich hydrothermal fluid. Further, up to 9 wt.% Co concentrations in PyII show a temperature condition of

  4. An aqueous friendly chemosensor derived from vitamin B6 cofactor for colorimetric sensing of Cu2 + and fluorescent turn-off sensing of Fe3 +

    Science.gov (United States)

    Sharma, Darshna; Kuba, Aman; Thomas, Rini; Kumar, Rajender; Choi, Heung-Jin; Sahoo, Suban K.

    2016-01-01

    Chemosensor L derived from vitamin B6 cofactor pyridoxal-5-phosphate was investigated for the selective detection of Cu2 + and Fe3 + in aqueous medium. Sensor L formed a 1:1 complex with Cu2 + and displays a perceptible color change from colorless to yellow brown with the appearance of a new charge transfer band at ~ 450 nm. In contrast, the fluorescence of L was quenched selectively in the presence of Fe3 + without any interference from other metal ions including Cu2 +.

  5. Copper-promoted circumneutral activation of H2O2 by magnetic CuFe2O4 spinel nanoparticles: Mechanism, stoichiometric efficiency, and pathway of degrading sulfanilamide.

    Science.gov (United States)

    Feng, Yong; Liao, Changzhong; Shih, Kaimin

    2016-07-01

    To evaluate the heterogeneous degradation of sulfanilamide by external energy-free Fenton-like reactions, magnetic CuFe2O4 spinel nanoparticles (NPs) were synthesized and used as catalysts for activation of hydrogen peroxide (H2O2). The physicochemical properties of the CuFe2O4 NPs were characterized with several techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and magnetometry. In the catalytic experiments, CuFe2O4 NPs/H2O2 oxidation showed the best degradation performance in the circumneutral conditions that resulted from the presence of Cu(II) on the surface of the CuFe2O4 NPs. The surface area-normalized pseudo-first-order rate constants were calculated as 2.60 × 10(-2) L m(-1) min(-1), 2.58 × 10(-3) L m(-1) min(-1), 1.92 × 10(-3) L m(-1) min(-1), and 7.30 × 10(-4) L m(-1) min(-1) for CuO, CuFe2O4 NPs, Fe3O4, and α-Fe2O3 catalysts, respectively. Thus, solid state Cu(II) was more reactive and efficient than Fe(III) in the circumneutral activation of H2O2; this finding was further supported by the results regarding the stoichiometric efficiency of H2O2. The effects of experimental parameters such as the oxidant dosage and catalyst loading were investigated. The mechanism for H2O2 activation on the spinel surface was explored and could be explained by the solid redox cycles of Fe(II)/Fe(III) and Cu(II)/Cu(I). Based on the products detected, a degradation pathway via the CS bond cleavage is proposed for the degradation of sulfanilamide. The findings of this study suggest that copper can be used as a doping metal to improve the reactivity and expand the effective pH range of iron oxides. PMID:27085318

  6. Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors

    Science.gov (United States)

    Jain, Syadwad

    In this study, the localized corrosion and conversion coating on cast alloys 356 (Al-7.0Si-0.3Mg) and 380 (Al-8.5Si-3.5Cu-1.6Fe) were characterized. The intermetallic phases presence in the permanent mold cast alloy 356 are primary-Si, Al5FeSi, Al8Si6Mg3Fe and Mg2Si. The die cast alloy 380 is rich in Cu and Fe elements. These alloying elements result in formation of the intermetallic phases Al 5FeSi, Al2Cu and Al(FeCuCr) along with primary-Si. The Cu- and Fe-rich IMPS are cathodic with respect to the matrix phase and strongly govern the corrosion behavior of the two cast alloys in an aggressive environment due to formation of local electrochemical cell in their vicinity. Results have shown that corrosion behavior of permanent mould cast alloy 356 is significantly better than the die cast aluminum alloy 380, primarily due to high content of Cu- and Fe-rich phases such as Al2Cu and Al 5FeSi in the latter. The IMPS also alter the protection mechanism of the cast alloys in the presence of inhibitors in an environment. The presence of chromate in the solution results in reduced cathodic activity on all the phases. Chromate provides some anodic inhibition by increasing pitting potentials and altering corrosion potentials for the phases. Results have shown that performance of CCC was much better on 356 than on 380, primarily due to inhomogeneous and incomplete coating deposition on Cu- and Fe- phases present in alloy 380. XPS and Raman were used to characterize coating deposition on intermetallics. Results show evidence of cyanide complex formation on the intermetallic phases. The presence of this complex is speculated to locally suppress CCC formation. Formation and breakdown of cerium conversion coatings on 356 and 380 was also analyzed. Results showed that deposition of cerium hydroxide started with heavy precipitation on intermetallic particles with the coatings growing outwards onto the matrix. Electrochemical analysis of synthesized intermetallics compounds in the

  7. Stability of metastable phase and soft magnetic properties of bulk Fe-B nano-eutectic alloy prepared by undercooling solidification combined with CU-mold chilling

    Science.gov (United States)

    Yang, Changlin; Zhang, Jun; Huang, Huili; Song, Qijiao; Liu, Feng

    2015-11-01

    Bulk Fe83B17 nano-eutectic alloys were prepared by undercooling solidification combined with Cu-mold chilling method. Stable phase Fe2B and metastable phase Fe3B were found to coexist in the as-solidified microstructure. The soft magnetic properties were improved significantly by the nano-lamellar eutectic and the metastable phase and, were increased further by annealing at 1173 K for 1.5 h after which the metastable phase was decomposed completely.

  8. Thermomagnetic analysis of amorphous (CoxFe1-x)73.5Nb3Cu1Si13.5B9 metallic glasses

    International Nuclear Information System (INIS)

    Metallic glass samples of (CoxFe1-x)73.5Nb3Cu1Si13.5B9 are studied by thermomagnetic analysis. The Curie temperature increases with the substitution of Fe by Co, and crystallization temperature decreases. A simple consideration of the alloy as the sum of two magnetic systems is applied with good results. The observed discrepancies are explained as due to a magnetic interaction between the Co and Fe atoms

  9. Spin crossover at magnetic phase transformation in YBa sub 2 (Cu sub 1 sub - sub x Fe sub x) sub 3 O sub 7 sub+- subdelta superconductors

    CERN Document Server

    Lyubutin, I S

    2001-01-01

    It is established that all iron ions in the Cu1 and Cu2 local nodes in the YBa sub 2 (Cu sub 0 sub . sub 9 sup 5 sup 7 Fe sub 0 sub . sub 1) sub 3 O sub 7 sub . sub 0 sub 1 superconducting compound with the T sub c = 31 K at the temperature below T sub m = 22 K become magneto-ordered. Thus, the magnetic order by the T < T sub m coexists with the superconductivity. It is determined through the Moessbauer spectroscopy method that the iron ions in the Cu2 (Fe2) nodes at the temperature T < T sub m are in the low-spin state (S 3/2 or 1/2), whereas the same quantity of the iron ions in the Cu1 (Fe1) nodes is in the Fe sup 3 sup + high-spin state (S = 5/2). By the magnetic transition near T sub m these ions change the spin values and transit form low-spin state to the high-spin one and vice versa. Control measurements on other samples of the YBa sub 2 (Cu sub 1 sub - sub x Fe sub x) sub 3 O sub 7 sub+- subdelta series confirm these conclusions

  10. SRXRF elemental mapping and source analysis of Pb, Fe, Cu and Zn in human hair from an inhabitant in a lead-zinc mining area

    International Nuclear Information System (INIS)

    Elemental mapping of human hair may gain new insights for studying effects of mining environmental pollution on human health. SRXRF micro-analyses were conducted for longitudinal and transversal mapping of Pb, Fe, Cu and Zn relative intensities in hair sample collected from an inhabitant in Qixia lead-zinc mining area, Nanjing, Jiangsu province, China. The Pb relative intensity was low in hair follicle and root, but it increased with the hair growth. The longitudinal Pb accumulation in the hair shaft revealed a strong dependence on continuous exposure to the environment, while Fe, Cu and Zn relative intensities in the hair shaft were comparatively stable. The cortical proteins contributed to a high retention of Pb, Fe, Cu and Zn, while small quantities of all the elements but Zn were distributed in the cuticle. Medullar proteins were confirmed to contribute to slightly lower retention of Zn and Cu than cortical, but Pb and Fe were not detected in medulla. The sources of Pb in the hair were mostly exogenous contamination, and Fe, Cu and Zn were related to endogenous uptake. Zn and Cu participated in the entire metabolic process of hair growth. The study shows that SRXRF is of significance for biogeochemistry research. (authors)

  11. Effect of Cu doping and annealing treatment on the microstructure and magnetic properties of nanocrystalline single-phase Nd-Fe-B alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of Cu addition and annealing treatment on the magnetic properties and microstructure of Nd12.3Fe81.7-xCuxB6 (x=0-1.2 ribbons melt-spun and annealed were systematically investigated by the methods of vibrating sample magnetometer (VSM),X-ray diffraction (XRD),and transmission electron microscopy (TEM).Optimum magnetic properties were achieved by annealing melt-spun Nd12.3Fe81.5Cu0.2B6 ribbons at 550℃ for 15 min,which only contained Nd2Fe14B phase.The remanence,coercive force,and maximum energy product increase by 18.4%,36.2%,and 49% respectively compared with those of Cu-free samples.The significant improvement in magnetic properties originates from the finer grains of the samples by introducing Cu,which leads to the stronger exchange-coupling between neighboring grains.

  12. Effects of preparation methods on the performance of Cu-Mo-Fe-Ox in the hydrogen production from water

    Institute of Scientific and Technical Information of China (English)

    Si Chen; Wei Chu; Xu Liu; Dongge Tong

    2011-01-01

    Two Cu-Mo-Fe-Ox samples,which can store and supply pure hydrogen through repeated redox reaction (Fe3O4+4H2(→)3Fe+4H2O),were prepared by co-precipitation (FCM-C) and impregnation (FCM-I) methods,respectively,and the performance of hydrogen production from water were investigated.Compared with the impregnated sample,the co-precipitation sample presented better catalytic activity.The samples were characterized by X-ray diffraction (XRD),field emission scanning electron microscopy (FE-SEM),X-ray photoelectron spectroscopy (XPS),Fourier transform infrared spectroscopy (FT-IR) and temperature-programmed reduction (H2-TPR) techniques.XRD,FE-SEM and XPS results suggest that the FCM-C sample has smaller particle size and higher dispersion of iron oxide than that of FCM-I sample.In addition,FT-IR and H2-TPR analyses indicate that the weak interaction among metal oxides in FCM-C sample may induce facile reduction of active metal and superior property of hydrogen production by decomposing water in succession.

  13. A first-principles study on the magnetism of an Fe chain along the [110] direction on Cu(001)

    Science.gov (United States)

    Jiu Jin, Ying; Gee Kim, In; Lee, Jae Il

    2004-06-01

    Magnetic nanowires currently attract much attention due to possible applications in high-density memory storage. The cover picture, taken from the Editor's Choice paper [1] of this issue, is the spin density contour plot for a Fe chain along the [110] direction on Cu(001) and shows a large eruption of the majority spins from the Fe atom site toward the vacuum region. The supported Fe chain exhibits a large enhanced magnetic moment of the Fe atom compared with that of bulk Fe.The corresponding author, Jae Il Lee, is Professor at the Inha University, Incheon. His research group at the Department of Physics works on theoretical investigations of electronic structure and magnetism of materials using first-principles energy band calculations.This paper is a contribution from the International Symposium on Magnetic Materials and Applications and Winter Conference of the Korean Magnetics Society (2003 SOMMA/KMS Meeting), Daejeon, Korea, 3-6 December 2003. The proceedings of this conference are published in two parts in the present issue of phys. stat. sol. (b) and in phys. stat. sol. (a) 201, No. 8 (2004).

  14. Synthesis of nanostructured M/Fe{sub 3}O{sub 4} (M = Ag, Cu) composites using hexamethylentetramine and their electrocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Pan Lu, E-mail: panlu1970@163.com [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China) and Anhui Key Laboratory of Low temperature Co-fired Material, Huainan Normal University, Huainan 232001 (China); Chen Yonghong [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China); Anhui Key Laboratory of Low temperature Co-fired Material, Huainan Normal University, Huainan 232001 (China); Wang Fengwu [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer An easily controlled one-step synthesis was designed via a hydrothermal method. Black-Right-Pointing-Pointer Ag/Fe{sub 3}O{sub 4} hybrids and Cu/Fe{sub 3}O{sub 4} nano- and microspheres were successfully synthesized. Black-Right-Pointing-Pointer No surfactant was used in the synthesis. Black-Right-Pointing-Pointer Ag/Fe{sub 3}O{sub 4} hybrids and Cu/Fe{sub 3}O{sub 4} were modified on a GCE directly. Black-Right-Pointing-Pointer The samples all exhibited enhanced catalytic property for p-nitrophenol reduction. - Abstract: Nanoscaled Ag/Fe{sub 3}O{sub 4} hybrids with different Ag contents and Cu/Fe{sub 3}O{sub 4} nanoshpere and microsphere were successfully synthesized with assistance of sodium citrate and (CH{sub 2}){sub 6}N{sub 4} via a hydrothermal process. The as-prepared samples were identified and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS), respectively. All samples were used as electrocatalysts modified on a glassy carbon electrode for p-nitrophenol reduction in a basic solution. The catalytic activity of Ag/Fe{sub 3}O{sub 4} samples increased first and then decreased by increasing Ag content from 0% to 8%, and the one with 6% Ag displayed the highest catalytic activity. All the Cu/Fe{sub 3}O{sub 4} samples exhibited enhanced catalytic activity by comparison with a glassy carbon electrode, and the one prepared with the molar ratio of Cu{sup 2+}, Fe{sup 3+}, citrate anion, and (CH{sub 2}){sub 6}N{sub 4} with 1:1:3:5 exhibited the highest catalytic activity.

  15. Cu, Fe, or Ni doped molybdenum oxide supported on Al2O3 for the oxidative dehydrogenation of ethylbenzene

    Institute of Scientific and Technical Information of China (English)

    Tiago Pinheiro Braga; Antônio Narcísio Pinheiro; Edson R. Leite; Regina Cláudia R. dos Santos; Antoninho Valentini

    2015-01-01

    Molybdenum-based catalysts supported on Al2O3 doped with Ni, Cu, or Fe oxide were synthesized and used in ethylbenzene dehydrogenation to produce styrene. The molybdenum oxide was sup-ported using an unconventional route that combined the polymeric precursor method (Pechini) and wet impregnation on commercial alumina. The samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherms, temperature-programmed reduction of H2 (H2-TPR), and thermogravimetric (TG) analysis. XRD results showed that the added metals were well dis-persed on the alumina support. The addition of the metal oxide (Ni, Cu, or Fe) of 2 wt% by wet im-pregnation did not affect the texture of the support. TPR results indicated a synergistic effect be-tween the dopant and molybdenum oxide. The catalytic tests showed ethylbenzene conversion of 28%–53% and styrene selectivity of 94%–97%, indicating that the addition of the dopant improved the catalytic performance, which was related to the redox mechanism. Molybdenum oxides play a fundamental role in the oxidative dehydrogenation of ethylbenzene to styrene by its redox and acid–base properties. The sample containing Cu showed an atypical result with increasing conver-sion during the reaction, which was due to metal reduction. The Ni-containing solid exhibited the highest amount of carbon deposited, shown by TG analysis after the catalytic test, which explained its lower catalytic stability and selectivity.

  16. COMPARISON OF DIFFERENT EXTRACTION METHODS REPRESENTING AVAILABLE AND TOTAL CONCENTRATIONS OF Cd, Cu, Fe, Mn and Zn IN SOIL

    Directory of Open Access Journals (Sweden)

    Vladimir Ivezić

    2013-06-01

    Full Text Available Various extraction methods are used to predict plant uptake of trace metals. Most commonly it is total concentration that is used for risk assessment and evaluation of trace metal availability. However, recent studies showed that total concentration is a poor indicator of availability while concentrations in soil solution show good correlation with plant uptake. Present study was conducted on magricultural soils with low levels of trace metals where 45 soil samples were collected from different soil types. The main objective was to compare four different extraction methods and examine how total and reactive (EDTA trace metal concentrations correlate ,with soil solution concentration (in this study determined by water extraction. The samples were analyzed by four extraction methods: strong acid extraction (ultra-pure HNO3 extraction and aqua regia, weak acid extraction by EDTA and the most available fraction, fraction in soil solution, were represented by water extraction (weakest extractant. Five elements were investigated (Cd, Cu, Fe, Mn and Zn. Water extraction significantly correlated with EDTA extraction for Cu, Fe and Mn, while total extraction (HNO3 extraction and aqua regia correlated significantly with water extraction only for Cu. No correlation between water extraction and total extraction confirmed poor role of total concentration as an indicator of availability. EDTA extraction can be used to represent reactive pool of trace metals in soil but it should be also taken with caution when using it to describe available fraction.

  17. No evidence of Fe transfer between Cu1 and Cu2 sites in YBa[sub 2](Cu[sub 1-x]Fe[sub x])[sub 3]O[sub 7-d] (0. 02 [<=] x [<=] 0. 04) annealed in an inert atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Terziev, V.G. (Lab. de Magnetisme et Materiaux Magnetiques, CNRS, 92 - Meudon (France) Inst. of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation)); Dormann, J.L. (Lab. de Magnetisme et Materiaux Magnetiques, CNRS, 92 - Meudon (France)); Maknani, J. (Lab. de Magnetisme et Materiaux Magnetiques, CNRS, 92 - Meudon (France)); Pankowska, H. (Lab. de Physique des Solides, CNRS, 92 - Meudon (France)); Gorochov, O. (Lab. de Physique des Solides, CNRS, 92 - Meudon (France)); Suryanarayanan, R. (Lab. de Physique des Solides, CNRS, 92 - Meudon (France))

    1993-05-10

    YBa[sub 2](Cu[sub 1-x]Fe[sub x])[sub 3]O[sub 7-d] (0.02 [<=] x [<=] 0.04) annealed in an Ar atmosphere, then reoxygenated have been characterized (X-ray diffraction, Tc) and studied by Moessbauer spectroscopy at room and low temperatures. The results are interpreted as due to Fe clustering rather than to a significant occupation in the plane. (orig.)

  18. 负载Cu、Fe物种的ZSM-5催化剂的研究%Study of ZSM-5 Catalyst Supported Cu and Fe Species

    Institute of Scientific and Technical Information of China (English)

    王东; 张国; 王滨发; 董永利; 袁福龙; 朱宇君

    2007-01-01

    通过离子交换法合成了Fe-ZSM-5、Cu-ZSM-5、Cu-Fe-ZSM-5催化剂,利用XRD、TG-DTA、IR手段对催化剂进行了表征.讨论了离子交换次数、种类及加入非选择性还原剂对催化分解NO的影响.结果表明:随着Fe物种负载量的增加,催化活性有所提高;与Fe-ZSM-5和Cu-ZSM-5催化剂相比,ex-Fe+Cu催化剂的催化活性有较大的提高.在CO还原剂存在下,NO的转化率可达到80%.

  19. Kinetic analysis of the non-isothermal crystallization process, magnetic and mechanical properties of FeCoBSiNb and FeCoBSiNbCu bulk metallic glasses

    Science.gov (United States)

    Ramasamy, Parthiban; Stoica, Mihai; Taghvaei, A. H.; Prashanth, K. G.; Ravi Kumar, Eckert, Jürgen

    2016-02-01

    The crystallization kinetics of [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4 and {[(Fe0.5Co0.5)0.75B0.2Si0.05]0.96Nb0.04}99.5Cu0.5 bulk metallic glasses were evaluated using differential scanning calorimetry under non-isothermal condition. The fully glassy rods with diameters up to 2 mm were obtained by copper mold injection casting. Both glasses show good thermal stability, but the addition of only 0.5% Cu completely changes the crystallization behavior. The average activation energy required for crystallization decreases from 645 kJ/mol to 425 kJ/mol after Cu addition. Upon heating, the Cu-free alloy forms only the metastable Fe23B6 phase. In contrast, two well-separated exothermic events are observed for the Cu-added bulk glassy samples. First, the (Fe,Co) phase nucleates and then (Fe,Co)2B and/or (Fe,Co)3B crystallize from the remaining glassy matrix. The Cu-added alloy exhibits a lower coercivity and a higher magnetic saturation than the base alloy, both in as-cast as well as in annealed condition. Besides, the Cu-added glassy sample with 2 mm diameter exhibits a maximum compressive fracture strength of 3913 MPa together with a plastic strain of 0.6%, which is highest plastic strain ever reported for 2 mm diameter ferromagnetic bulk metallic glass sample. Although Cu addition improves the magnetic and mechanical properties of the glass, it affects the glass-forming ability of the base alloy.

  20. Structural and magnetic changes in FeNbCuSiB amorphous alloys during the crystallization process

    International Nuclear Information System (INIS)

    Calorimetric and magnetic measurements, x-ray powder diffraction and Moessbauer spectroscopy have been used to study the magnetic and structural changes occurring after each of the two steps of crystallization that take place in FeNbCuSiB-type alloys. Two samples with different boron and silicon concentrations, Fe73.5Nb3Cu1Si22.5-xBx (x=6, 9), have been studied. They give a somewhat different composition of the crystalline phases appearing after crystallization processes. The most noticeable phenomenon is the observed increase of about 50 K in the Curie temperature of the FeSi crystalline phase between the end of the first crystallization process and the end of the second one, although the composition of this phase remains unchanged. This result is discussed in terms of crystal boundary effects. Also, the Curie temperature of the remaining amorphous phase, in the crystallized samples, is greater than the expected one, due to the coupling with magnetic phases with higher Curie points and inhomogeneities in such a phase. (author)

  1. Effect of Cr on Microstructure and Properties of a Series of AlTiCr x FeCoNiCu High-Entropy Alloys

    Science.gov (United States)

    Li, Anmin; Ma, Ding; Zheng, Qifeng

    2014-04-01

    A series of AlTiCr x FeCoNiCu ( x: molar ratio, x = 0.5, 1.0, 1.5, 2.0, 2.5) high-entropy alloys (HEAs) were prepared by vacuum arc furnace. These alloys consist of α-phase, β-phase, and γ-phase. These phases are solid solutions. The structure of α-phase and γ-phase is face-centered cubic structure and that of β-phase is body-centered cubic (BCC) structure. There are four typical cast organizations in these alloys such as petal organization (α-phase), chrysanthemum organization (α-phase + β-phase), dendrite (β-phase), and inter-dendrite (γ-phase). The solidification mode of these alloys is affected by Chromium. If γ-phase is not considered, AlTiCr0.5FeCoNiCu and AlTiCrFeCoNiCu belong to hypoeutectic alloys; AlTiCr1.5FeCoNiCu, AlTiCr2.0FeCoNiCu, and AlTiCr2.5FeCoNiCu belong to hypereutectic alloys. The cast organizations of these alloys consist of pro-eutectic phase and eutectic structure (α + β). Compact eutectic structure and a certain amount of fine β-phase with uniform distribution are useful to improve the microhardness of the HEAs. More γ-phase and the microstructure with similar volume ratio values of α-phase and β-phase improve the compressive strength and toughness of these alloys. The compressive fracture of the series of AlTiCr x FeCoNiCu HEAs shows brittle characteristics, suggesting that these HEAs are brittle materials.

  2. Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La1.65Sr0.45CuO4/La2CuO4 films and the organic superconductors κ-(BEDT-TTF)2Cu[N(CN)2]Br

    Science.gov (United States)

    Gasparov, V. A.; He, Xi; Dubuis, G.; Pavuna, D.; Kushch, N. D.; Yagubskii, E. B.; Schlueter, J. A.; Bozovic, I.

    2015-09-01

    We used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La1.65Sr0.45CuO4, LSCO) and a cuprate insulator (La2CuO4, LCO), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κ-(BEDT-TTF)2Cu[N(CN)2]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, Lk-1(T) occurs at a temperature lower by 2 K than in Reσ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski-Kosterlitz-Thouless (BKT) transition and dynamics of bound vortex-antivortex pairs with short separation lengths.

  3. Interface Characteristics of AgNi10/Cu/Fe by Cold Roll Bonding%冷轧复合AgNi10/Cu/Fe界面结合特征研究

    Institute of Scientific and Technical Information of China (English)

    王勇; 刘安利; 徐永红; 章应; 杨贤军

    2011-01-01

    采用等辊径、等辊速冷轧复合技术制备了AgNi10/Cu/Fe三层复合材料,对其界面结合机制进行了研究.复合前对三层材料分别进行再结晶退火,获得均匀的原始组织及相近的硬度,并用钢丝刷清理复合面.利用扫描电镜和能谱仪对复合材料的剥离面进行了形貌观察和成分分析.结果发现,AgNi10/Cu/Fe的界面结合机制主要是裂口机制.各层复合面的硬化层在轧制时开裂,其中较软金属(AgNi10和Cu)从裂口中挤出,与硬金属(Cu和Fe)产生结合;其结合强度分别大于AgNi10和Cu的基体强度.%AgNi10/Cu/Fe layered composites were prepared by cold roll bonding with equal-roller-diameter and equal-rolling-speed. The interface bonding mechanism was investigated. The raw tapes of the AgNi10, Cu and Fe were singly annealed before bonding so as to obtain homogeneous recrystallized microstructures and similar hardness. The surfaces to be bonded were cleaned by a scratch brush just before entering the roll gap. After bonding, the peeled interfaces of the composites were analyzed by SEM and EDS. Results show that the bonding mechanism of the as-rolled interfaces is primarily cracking. During roll bonding, the work-hardened surface layers are fractured. Virgin metals of the softer layers (AgNi10 and Cu for AgNi10/Cu and Cu/Fe respectively) are extruded from the cracks and bonded with the harder ones (Cu and Fe). The bonding strength is greater than the fracture strength of AgNilO and Cu in AgNilO/Cu and Cu/Fe.

  4. Plastic Deformation of Fine-Grained Al-Cu-Fe-(B) Icosahedral Poly-Quasicrystals at Elevated Temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Bo; MA Jia-Yan; LU Lu; XIONG Dong-Xia; ZHAO Dong-Shan; WANG Ren-Hui

    2007-01-01

    @@ Fine-grained Al-Cu-Fe-(B) icosahedral poly-quasicrystals (IQCs) as the main materials and fine-grained Al-Pd-Mn IQCs as the supplements, both prepared by powder metallurgy, are uniaxially deformed at various temperatures and strain rates. The systematic study shows the dependences of curves of the true stress versus true strain on several parameters, such as temperature, strain rate and grain size. For Al-Cu-Fe IQCs with grain sizes of about 10-30 μm, QC-specific intra-granular softening drop appears in the deformation curves at lower temperatures and/or faster strain rates, but disappears in those curves at higher temperatures and/or slower strain rates, which suggests that the inter-granular effects such as grain-boundary sliding should be taken into account to interpret the continuous hardening, similarly to conventional poly-crystals. For Al-Cu-Fe-B IQCs with smaller grain sizes of about 1 μm and fine-grained Al-Pd-Mn IQCs with grain sizes of about 10 μm, QC-specific intra-granular softening drop is absent for all the deformation curves at the possible lowest temperature and fastest strain rate. This implies that the smaller the grain size, the more the inter-granular contribution.At the same time, due to the rapid recovery caused by intense diffusion in small-sized grains, the intra-granular quasicrystal lattice reorders rapidly from disordering, which also inhibits the intra-granular softening drop to some extent.

  5. Determination of soil micronutrients (Fe, Cu, Mn, B) extracted by Mehlich 3 using MP-AES

    Science.gov (United States)

    Krebstein, Kadri; Tõnutare, Tõnu; Rodima, Ako; Kõlli, Raimo; Künnapas, Allan; Rebane, Jaanus; Penu, Priit; Vennik, Kersti; Soobik, Liina

    2015-04-01

    The total concentration of micronutrients in soils is not a good predictor of its bioavailability and solubility. Therefore, during the decades several methods for the determination of plant availability and extractable fraction of micro- and macronutrients in soil were developed. Among several methods Mehlich 3 is the most appropriate due to its suitability for extracting soil micro- and macronutrients simultaneously. The AAS (atomic absorption spectroscopic) and ICP (inductively coupled plasma) methods are widely used for the analysis of microelements today. In 2011 the third method was added to this list with the appearance of the microwave plasma atomic emission spectrometer (MP-AES). This multielemental analytical equipment has a high potential in the soil analysis. Up to now there have been made some experiments for the use of MP-AES in soil and geological material analysis. But there is no information about the analysis of soil micronutrients extracted according to Mehlich 3 method and determined with the MP-AES. Due to the differences in atomization conditions the different emission and absorption lines are used in different instrumental methods. Therefore it is very important to choose the most suitable emission lines and the best atomization conditions. From the analytical viewpoint it is important to get coincidental results with other instrumental methods and from the agronomical point of view it is important to know the difference between AAS and ICP methods. For the experiment 51 soil samples were used. The samples were collected from A horizons of agricultural lands. The pH range was from 4.7 to 7.5 and organic matter content from 1.4 to 7.8%. The content of Mehlich 3 extractable micronutrients was determined using ICP and MP instrumental methods. The micronutrient contents ranged as follows: Fe - from 170 to 470 mg kg-1, Mn - from 5 to 190 mg kg-1, Cu - from 0.3 to 4.5 mg kg-1, B - from 0.2 to 2.1 mg kg-1. The optimal instrumental settings for iron

  6. Role of aluminium addition on structure of Fe substituted Fe73.5−Si13.5B9Nb3Cu1Al alloy ribbons

    Indian Academy of Sciences (India)

    Gautam Agarwal; Himanshu Agrawal; M Srinivas; B Majumdar; N K Mukhopadhyay

    2013-08-01

    The investigation has dealt with the structure and magnetic properties of rapidly solidified and annealed Fe73.5−Si13.5B9Nb3Cu1Al ( = 0, 2, 4, 6 at%) ribbons prepared by melt spinning. Complete amorphous structure was obtained in as-spun ribbons of = 0 and 2 at% compositions, whereas structure of ribbons containing higher Al was found to be partially crystalline. Detailed thermal analyses of the alloys and the melt spun ribbons revealed that the glass forming ability in the form of x/l (ratio between crystallization and liquidus temperature) is the highest for 2 at% Al alloys and decreases with further addition of Al. Annealing of all as spun ribbons resulted in the precipitation of nanocrystalline phase embedded in amorphous matrix in the form of either 3 phase or -Fe(Si/Al) solid solution depending on the initial composition of the alloy. Only -Fe(Si/Al) solid solution was formed in 2 at% Al ribbons whereas ordered DO3 structure was found to be stabilized in other ribbons including 0 at% Al. A detailed study on determination of precision lattice parameter of nanocrystalline phase revealed that the lattice parameter increases with the addition of Al indicating the partitioning behaviour of Al in nanocrystalline phase.

  7. Kinetika odstranjivanja olova iz Cu-Pb-Fe legure pročišćavanjem inertnim plinom

    OpenAIRE

    B. Oleksiak; L. Blacha

    2011-01-01

    Diskusija o kinetic odstranjivanja olova iz Cu-Pb-Fe legure pročišćavanjem argonom i helijem. Vrijednosti koeficijenta masene penetracije za tekuću i krutu fazu kao i za koeficijent masenog prijenosa su izračunati za temperature 1473 K i 1548 K, te za protok plina 5,55 • 10-6, 6,94 • 10-6, 8,33 • 10-6 and 9,72 • 10-6 m • s-1.

  8. Recrystallization and development of cube texture in Ti and Ti+Cr added Ni-Fe-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Manna, I. (Dept. of Metallurgical Engineering , I.I.T., Kharagpur (India)); Ray, R.K. (Dept. of Metallurgical Engineering, I.I.T., Kanpur (India)); Gupta, K.P. (Dept. of Metallurgical Engineering, I.I.T., Kanpur (India))

    1994-06-01

    The development of a sharp cube or [l brace]100[r brace]<100> texture in two Ti and Ti+Cr added Ni-Fe-Cu alloys is presented. Texture studies in deformed as well as recrystallized conditions have been carried out by both conventional pole figure and orientation distribution function analysis. Microstructural evolution in course of recrystallization texture development has been extensively studied with both optical and electron microscopes. Heavy cold deformation (97 to 98%) followed by annealing at 1050 C for 2 h has been found to optimize the conditions for the desired texture development. (orig.)

  9. Long-range magnetic order and spin-lattice coupling in delafossite CuFeO2

    Science.gov (United States)

    Eyert, Volker; Frésard, Raymond; Maignan, Antoine

    2008-08-01

    The electronic and magnetic properties of the delafossite CuFeO2 are investigated by means of electronic structure calculations. They are performed using density functional theory in the generalized gradient approximation, as well as the new full-potential augmented spherical wave method. The calculations reveal three different spin states at the iron sites. Using for the first time the experimentally determined low-temperature crystal structure, we find long-range antiferromagnetic ordering in agreement with experiment. In addition, our calculations show that nonlocal interactions as covered by the generalized gradient approximation lead to a semiconducting ground state.

  10. Structural characterization of CuFe/sub 2/O/sub 4/ nanocomposites and synthesis by an economical method

    International Nuclear Information System (INIS)

    Copper ferrites were prepared through co-precipitation technique. The aim of this effort was to present a novel and economical method of preparation of copper ferrites via co-precipitation technique. Structural properties were studied with the help of XRD technique while micro structural study of the samples was carried out by SEM. The particle size was calculated with the help of Scherrer's formula using characteristic peaks. The SEM images showed uniformity and homogeneity of the synthesized CuFe/sub 2/O/sub 4/ particles. (author)

  11. Cu/Fe-cocatalyzed Meyer-Schuster-like rearrangement of propargylic amines: direct access to E-β-aminoacryaldehydes.

    Science.gov (United States)

    Chen, Ming; Peng, Jiangling; Mao, Tingting; Huang, Jinbo

    2014-12-19

    A simple and efficient method for the synthesis of β-aminoacryaldehydes via Cu(OAc)2·H2O and FeCl3 cocatalyzed Meyer-Schuster-Like rearrangement of propargylic amines was developed. The reactions proceed selectively as the E-isomers in generally good yields under aerobic conditions, and are compatible with a broad range of functional groups. This method combines C-N bond cleavage as well as the N-aryl group migration and provides a practical and mild synthetic approach to α,β-unsaturated carbonyl compounds, which are useful precursors in a variety of functional group transformations. PMID:25453833

  12. Densities of Molten and Solid Alloys of (Fe, Cu, Ni, Co)-S at Elevated Temperatures - Literature Review and Analysis

    OpenAIRE

    Tesfaye, Fiseha; Taskinen, Pekka

    2010-01-01

    Densities of solid and liquid Fe, Cu, Ni and Co, and their alloys both at the presence and absence of sulfur have been reviewed. Volumetric thermal expansions were used to estimate the densities at different temperatures. Densities of the alloys generally decrease with increasing temperature. For the pure metals the reduction in density as temperature rises from 25 oC to their respective melting point can be estimated to be about 7.05 ± 0.4 % just before melting and about 11.63 ± 0.92 on comp...

  13. Dielectric behaviour and a.c. conductivity in CuFe3–O4 ferrite

    Indian Academy of Sciences (India)

    A N Patil; M G Patil; K K Patankar; V L Mathe; R P Mahajan; S A Patil

    2000-10-01

    The dielectric properties (dielectric constant and loss) for the system CuFe3–O4 with = 1.0, 0.8, 0.6, 0.4 and 0.2, were studied in the temperature range 300 ∼ 800 K and also in the frequency range 1 kHz ∼ 1 MHz. A.c. conductivity was derived from dielectric constant and loss tangent data. The conduction in this system is interpreted as due to small polaron hopping. The dielectric relaxation was observed for the compositions with tetragonal structure whereas normal behaviour was observed for cubic structure.

  14. Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08354, and UNS N08926), and Cr-Ni-Fe-N Low-Carbon Alloy (UNS R20033) Bar and Wire, and Ni-Cr-Fe-Mo-N Alloy (UNS N08936) Wire

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2016-01-01

    Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08354, and UNS N08926), and Cr-Ni-Fe-N Low-Carbon Alloy (UNS R20033) Bar and Wire, and Ni-Cr-Fe-Mo-N Alloy (UNS N08936) Wire

  15. Competing mechanisms for ordering tendencies in BCC CuAuZn{sub 2} and FCC AuFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.D.; Althoff, J.D. [Sandia National Labs., Livermore, CA (United States); Staunton, J.B.; Ling, M.F. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Pinski, F.J. [Cincinnati Univ, OH (United States). Dept. of Physics

    1995-07-01

    We have briefly discussed the ASRO (atomic short-range order) in AuFe and CuAuZn{sub 2}. General points are that (1) we have implemented a first-principles theory of ASRO in N-component alloys which allows determination of the electronic origins of said ASRO; (2) such calculations can provide much information on the high- and (sometimes) low-temperature alloys; and (3) this approach has identified the origin for the novel special-point ASRO in AuFe. Displacement effects, i.e., non-rigid lattice effects, as well as the other contributions beyond band-energy, are being incorporated into the multicomponent alloy calculations. Such improvements will allow us to investigate other alloys, where charge effects may play a role, to ``design`, for example, higher temperature intermetallics through alloying.

  16. Local X-ray magnetic circular dichroism study of Fe/Cu(111) using a tunneling smart tip

    Energy Technology Data Exchange (ETDEWEB)

    DiLullo, Andrew; Shirato, Nozomi; Cummings, Marvin [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Kersell, Heath; Chang, Hao [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Ohio University, Athens, OH 45701 (United States); Rosenmann, Daniel; Miller, Dean; Freeland, John W. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Hla, Saw-Wai [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Ohio University, Athens, OH 45701 (United States); Rose, Volker, E-mail: vrose@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2016-01-28

    A tunneling smart tip of a synchrotron X-ray scanning tunneling microscope provides simultaneously localized topographic, elemental and magnetic information. Localized spectroscopy with simultaneous topographic, elemental and magnetic information is presented. A synchrotron X-ray scanning tunneling microscope has been employed for the local study of the X-ray magnetic circular dichroism at the Fe L{sub 2,3}-edges of a thin iron film grown on Cu(111). Polarization-dependent X-ray absorption spectra have been obtained through a tunneling smart tip that serves as a photoelectron detector. In contrast to conventional spin-polarized scanning tunneling microscopy, X-ray excitations provide magnetic contrast even with a non-magnetic tip. Intensity variations in the photoexcited tip current point to chemical variations within a single magnetic Fe domain.

  17. Magnetic Microstructures of 2:17 Type Sm(Co,Fe,Cu,Zr)z Magnets Detected by Magnetic Force Microscopy

    Institute of Scientific and Technical Information of China (English)

    Xia Ailin; Guo Zhaohui; Li Wei; Han Baoshan

    2006-01-01

    The magnetic microstructures of 2:17 type Sm(Co,Fe,Cu,Zr)z magnets were detected by magnetic force microscopy.Comparing the microstructures of the specimens coated with and without Ta thin film before and after heat-treatment, it is found that: (a) as a protection layer, Ta coating layer about 20 nm thick can effectively restrain Sm volatilization under high temperature;(b) the stress built in the 2:17 type Sm-Co magnets during specimen preparation only affects some local parts of the domain structures;(c) the magnetic microstructures vary largely for specimens heat-treated at high temperature without Ta film coating due to Sm volatilization.In addition, by comparing with high coercivity Fe-Pt point tips, it is found that the Co-Cr thin-film tips are not suitable for detecting the magnetic microstructures of strong permanent magnets.

  18. Lateral electric-field control of giant magnetoresistance in Co/Cu/Fe/BaTiO3 multiferroic heterostructure

    International Nuclear Information System (INIS)

    We report lateral electric-field-driven sizable changes in the magnetoresistance of Co/Cu/Fe tri-layered wires on BaTiO3 single crystal. While the observed change is marginal in the tetragonal phase of BaTiO3, it reaches over 40% in the orthorhombic and rhombohedral phases with an electric field of 66 kV/cm. We attribute it to possible electric-field-induced variations of the spin-dependent electronic structures, i.e., spin polarization, of the Fe via interfacial strain transfer from BaTiO3. The contrasting results for the different phases of BaTiO3 are discussed, associated with the distinct aspects of the ferroelectric polarization switching processes in each phase

  19. Effect of Sm Volatilization on Magnetic Microstructures of Sintered Sm(Co,Fe,Cu,Zr)z Magnets at High Temperatures

    Institute of Scientific and Technical Information of China (English)

    XIA Ai-Lin; FANG Yi-Kun; GUO Zhao-Hui; LI Wei; HAN Bao-Shan

    2006-01-01

    @@ We present a magnetic force microscopy study of surface magnetic microstructure changes at high temperatures in 2:17-type Sm( Co, Fe, Cu,Zr)z (z ~ 7.4) magnets. Surface magnetic microstructures are found to change greatly in parallel and vertical specimens after heat-treatment at 400℃ for one hour in vacuum of 10-5 Torr with Ar gas as protecting atmosphere. Changes of microstructures are attributed to the formation of a soft-magnetic surfaces layer in the specimens, resulting from Sm volatilization due to high temperature. This hypothesis is further confirmed by the heat-treatment experiments at 400℃ for 0.5 h and 2 h. Finally, the existence of the soft-magnetic layers, which consist primarily of Fe-Co compounds, is verified by the results of both XRD and XPS of the vertical specimens before and after heat-treatment.

  20. Experimental investigation of off-stoichiometry and 3d transition metal (Mn, Ni, Cu-substitution in single-crystalline FePt thin films

    Directory of Open Access Journals (Sweden)

    Takuya Ono

    2016-05-01

    Full Text Available In L10 (fct-FePt thin films, both tuning Fe and Pt concentrations and substitution with third-metal were studied for magnetic characteristic optimization. We investigated single-crystalline FePt-X (X = Mn, Ni, Cu thin films grown epitaxially on MgO(001 substrates at a substrate temperature of 350  °C by changing Fe, Pt, and X contents, and explored the effects of off-stoichiometry and 3d-metal-substitution. The magnetic moment per atom (m of FePt-X films as a function of the effective number of valence electrons (neff in 3d metal sites follows the Slater-Pauling-type trend, by which m decreases by the neff deviation from neff = 8, independently of the X metal and the Pt concentration. The magnetic anisotropy (Ku exhibits neff dependence similar to m. This trend was almost independent of the Pt concentration after compensation using the theoretical prediction on the relation between Ku and Fe/Pt concentrations. Such a trend has been proved for stoichiometric FePt-X films, but it was clarified as robust against off-stoichiometry. The compensated Ku ( K u comp of FePt-Mn and FePt-Cu followed a similar trend to that predicted by the rigid-band model, although the K u comp of the FePt-Mn thin films dropped more rapidly than the rigid band calculation. However, it followed the recent first-principles calculation.