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Sample records for br cu fe

  1. Magnetically separable CuFe{sub 2}O{sub 4}/AgBr composite photocatalysts: Preparation, characterization, photocatalytic activity and photocatalytic mechanism under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yalei; Lin, Cuiping; Bi, Huijie; Liu, Yonggang; Yan, Qishe, E-mail: Qisheyanzzu@163.com

    2017-01-15

    Highlights: • CuFe{sub 2}O{sub 4}/AgBr composites were prepared by a facile sol-gel and hydrothermal method. • Visible-light response and high photocatalytic performance. • Excellent magnetic properties. • Different reactive species had different effects on degradation different pollutants. - Abstract: The CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4}/AgBr composites with different CuFe{sub 2}O{sub 4} contents were prepared by a facile sol-gel and hydrothermal method, respectively. The as-synthesized photocatalysts were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectrum (UV–vis DRS). Their magnetic properties, photocatalytic degradation activities on methyl orange (MO) and tetracycline hydrochloride (TC) solution and photocatalytic mechanism were investigated in detail. The results revealed that the CuFe{sub 2}O{sub 4}/AgBr composites exhibited significantly higher photocatalytic activities than the pure CuFe{sub 2}O{sub 4}. The enhanced photocatalytic activity could be attributed to the matched band structure of two components and more effective charge transportation and separations. In addition, the quenching investigation of different scavengers demonstrated that h{sup +}, ·OH, ·O{sub 2}{sup −} reactive species played different roles in the decolorization of MO and degradation of TC.

  2. 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

    Energy Technology Data Exchange (ETDEWEB)

    Brune, D; Samsahl, K [AB Atomenergi, Nykoeping (Sweden); Wester, P O [Dept. of Medicine, Karolinska Inst., Serafimerlasarettet, Stockholm (Sweden)

    1964-01-15

    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 H{sub 2}SO{sub 4} - 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.

  3. TXRF and XRF techniques for the determination of K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr and Pb in some plant species and their infusion

    Energy Technology Data Exchange (ETDEWEB)

    Khuder, A [Atomic Energy Commission, Damascus (Syrian Arab Republic). Dept. of Chemistry

    2009-02-15

    The content of K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, and Sr elements in some medicinal plants, including: A. herba-alba, T. officinale, M. officinalis, T. syeriacus, T. vulgaris, A. officinalis, R. officinalis, M. piperita, M. aquatica, Zea mays, G. glabra, A. vulgare, U. urens, C. aronica, H. officinalis, M. aurea, C. cyminum, was determined using TXRF technique. Concentrations of Pb upper the detection limits of TXRF method was determined only in A. herba-alba leaves with a mean value of 3.6 ppm. The accuracy and the precision of TXRF method were verified using Apple leaves, Peach leaves, and Hay Powder Standard Reference Materials (SRM) for the analysis of plant samples. The previously mentioned elements were accurately determined by TXRF, except Br. Errors obtained by Br determination may be obtained by the partial losses of element content during evaporation of sample on quartz carrier proposed for TXRF measurements. TXRF results for Ca, Mn, and Sr elements agreed well with these obtained by XRF method with standard relative error (SR) better than 10 %, while, these obtained for rest elements, except Br, were with SR ranging between 11 %-20 %. Br was not included in the determination of elements by TXRF. Transfer of K, Ca, Mn, Fe, Cu, Zn, Br, Rb, and Sr from A. herba-alba, A. vulgare, Zea mays, M. aquatica, M. piperita, C. cyminum, G. glabra, M. officinalis, and R. officinalis plant materials to infusions at different temperatures were studied using XRF method. Data analyses were verified by Peach and Apple leaves of Standard Reference Materials. Potassium represented the dominant element in all studied plants, particularly, in roots of U. dioica plant with concentrations in the range of 59.3 g/Kg-90.8 g/Kg. Independently of brewing 5 temperature, potassium with a high ratio was transferred from plants to infusions. K transfer ratio was in a range from 57.2 % for A. vulgare leaves at 25 .C to 91 % for G. glabra at 55 .C. Although, Fe content in dry plant

  4. TXRF and XRF techniques for the determination of K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr and Pb in some plant species and their infusion

    International Nuclear Information System (INIS)

    Khuder, A.

    2009-02-01

    The content of K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, and Sr elements in some medicinal plants, including: A. herba-alba, T. officinale, M. officinalis, T. syeriacus, T. vulgaris, A. officinalis, R. officinalis, M. piperita, M. aquatica, Zea mays, G. glabra, A. vulgare, U. urens, C. aronica, H. officinalis, M. aurea, C. cyminum, was determined using TXRF technique. Concentrations of Pb upper the detection limits of TXRF method was determined only in A. herba-alba leaves with a mean value of 3.6 ppm. The accuracy and the precision of TXRF method were verified using Apple leaves, Peach leaves, and Hay Powder Standard Reference Materials (SRM) for the analysis of plant samples. The previously mentioned elements were accurately determined by TXRF, except Br. Errors obtained by Br determination may be obtained by the partial losses of element content during evaporation of sample on quartz carrier proposed for TXRF measurements. TXRF results for Ca, Mn, and Sr elements agreed well with these obtained by XRF method with standard relative error (SR) better than 10 %, while, these obtained for rest elements, except Br, were with SR ranging between 11 %-20 %. Br was not included in the determination of elements by TXRF. Transfer of K, Ca, Mn, Fe, Cu, Zn, Br, Rb, and Sr from A. herba-alba, A. vulgare, Zea mays, M. aquatica, M. piperita, C. cyminum, G. glabra, M. officinalis, and R. officinalis plant materials to infusions at different temperatures were studied using XRF method. Data analyses were verified by Peach and Apple leaves of Standard Reference Materials. Potassium represented the dominant element in all studied plants, particularly, in roots of U. dioica plant with concentrations in the range of 59.3 g/Kg-90.8 g/Kg. Independently of brewing 5 temperature, potassium with a high ratio was transferred from plants to infusions. K transfer ratio was in a range from 57.2 % for A. vulgare leaves at 25 .C to 91 % for G. glabra at 55 .C. Although, Fe content in dry plant

  5. 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.

    Science.gov (United States)

    Laursen, Jens; Milman, Nils; Pind, Niels; Pedersen, Henrik; Mulvad, Gert

    2014-01-01

    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. 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. Dual hierarchical clustering analysis, creating a dual dendrogram, one clustering element contents according to calculated similarities, one clustering elements according to correlation coefficients between the element contents, both using Euclidian distance and Ward Procedure. One dendrogram separated subjects in 7 clusters showing no differences in ethnicity, gender or age. 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, Br and Zn; Cl with S and Br; K with S, Br and Zn; Cu with Br. Zn with S and K. Br with S, Cl, K and Cu. Fe did not show significant associations with any other element. In contrast to simple statistical methods, which analyses content of elements separately one by one, dual hierarchical clustering analysis incorporates all elements at the same time and can be used to examine the linkage and interplay between multiple elements in tissue samples. Copyright © 2013 Elsevier GmbH. All rights reserved.

  6. Computer simulation of the structure of liquid metal halides RbBr, CuCl, CuBr, CuI, and AgBr

    International Nuclear Information System (INIS)

    Belashchenko, D.K.; Ostrovskij, O.I.

    2003-01-01

    The computerized models of the RbBr, AgBr, CuCl, CuBr and CuI liquid ion systems of 498 ions dimension are simulated at the temperatures of 753-960 K on the basis of the known diffraction data through the BELION algorithm. Good agreement of diffraction and model partial pair correlation functions (PPCF), excluding the PPCF first peaks heights, is obtained in all the cases. The simulation is carried out by the varied ion charges (the atomization energy values, close to the real ones, are obtained by ion charges ±1.00 for the RbBr, ±1.15 for AgBr, ±1.20 for CuCl, ±1.48 for CuBr and ±1.367 for CuI). The noncoulomb contributions in the interparticle potentials are calculated [ru

  7. FeBr3-catalyzed dibromination of alkenes and alkynes

    Institute of Scientific and Technical Information of China (English)

    Yun Fa Zheng; Jian Yu; Guo Bing Yan; Xu Li; Song Luo

    2011-01-01

    The dibromination of alkenes and alkynes with bromosuccinimide and sodium bromide catalyzed by FeBr3 under mild conditions has been developed. The trans-dibromo compounds were exclusively obtained with excellent yields.

  8. UV-Induced Anisotropy In CdBr2-CdBr2: Cu Nanostructures

    Directory of Open Access Journals (Sweden)

    El-Naggar A. M.

    2015-09-01

    Full Text Available We have found an occurrence of anisotropy in the nanostructure CdBr2-CdBr2: Cu nanocrystalline films. The film thickness was varied from 4 nm up to 80 nm. The films were prepared by successive deposition of the novel layers onto the basic nanocrystals. The detection of anisotropy was performed by occurrence of anisotropy in the polarized light at 633 nm He-Ne laser wavelength. The occurrence of anisotropy was substantially dependent on the film thickness and the photoinduced power density. Possible mechanisms of the observed phenomena are discussed.

  9. Mechanism insight of pollutant degradation and bromate inhibition by Fe-Cu-MCM-41 catalyzed ozonation.

    Science.gov (United States)

    Chen, Weirui; Li, Xukai; Tang, Yiming; Zhou, Jialu; Wu, Dan; Wu, Yin; Li, Laisheng

    2018-03-15

    A flexible catalyst, Fe-Cu-MCM-41, was employed to enhance diclofenac (DCF) mineralization and inhibit bromate formation in catalytic ozonation process. Greater TOC removal was achieved in Fe-Cu-MCM-41/O 3 process (78%) than those in Fe-MCM-41/O 3 (65%), Cu-MCM-41/O 3 (73%) and sole ozonation (42%). But it was interesting that both Cu-MCM-41/O 3 and Fe-MCM-41/O 3 achieved 93% bromate inhibition efficiency, only 71% inhibition efficiency was observed in Fe-Cu-MCM-41/O 3 . Influence of pH, TBA/NaHSO 3 and detection of by-products were conducted to explore the mechanism. By Pyridine adsorption-IR and XPS, a relationship was found among activity of catalysts, Lewis acid sites and electron transfer effect between Fe (II/III) and Cu (I/II). Fe-Cu-MCM-41 promoted ozone decomposition to generate OH, which accounted for enhanced DCF mineralization. The consumption of aqueous O 3 also suppressed the oxidative of Br - and HBrO/Br - . More HBrO/BrO - accumulated in catalytic ozonation process and less bromate generated. Bromate formation in Fe-Cu-MCM-41/O 3 process was sensitive with pH value, the acidic condition was not favor for bromate formation. Both DCF mineralization and bromate inhibition were influenced by surface reaction. Moreover, Fe-Cu-MCM-41 showed excellent catalytic performance in suppressing the accumulation of carboxylic acid, especially for oxalic acid. Nearly no oxalic acid was detected during Fe-Cu-MCM-41/O 3 process. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

  11. The growth of Fe clusters over graphene/Cu(111)

    International Nuclear Information System (INIS)

    Takahashi, Keisuke

    2015-01-01

    The growth of Fe clusters up to nine atoms over graphene/Cu(111) is investigated within the density functional theory. Graphene is weakly physisorbed on Cu(111) through van der Waals force. The structures of Fe clusters over graphene/Cu(111) grow differently compared to gas-phase Fe clusters where Fe clusters are predicted to form towards a pyramid-like structure on graphene/Cu(111). The graphene is negatively charged upon the adsorption of Fe clusters as a result of charge transfer from Fe to graphene. Despite the fact that the electronic structure of graphene is affected by Fe clusters, magnetic moment of Fe clusters over graphene/Cu(111) remains relatively high. This suggests that graphene can be a potential substrate for supporting Fe clusters towards applications in magnetism and catalysis. (paper)

  12. EPR Study of [Cu(Him)4]·2Br Complex

    International Nuclear Information System (INIS)

    Yıldırım, İ; Karabulut, B

    2016-01-01

    The single crystal of [Cu(Him) 4 ]·2Br (Him: C 3 H 4 N 2 , imidazole) complex has been investigated at ambient temperature in three mutually perpendicular planes by EPR technique. The magnetic environments of [Cu(Him) 4 ]·2Br complex have been identified by EPR technique. The study reveals the existence of two magnetically inequivalent Cu 2+ sites. The principal values of g tensors were obtained. The EPR parameters show that the paramagnetic centers have rhombic symmetry. (paper)

  13. 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.

  14. Simultaneous spectrophotometric determination of heavy metal ions Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) with Br-PADPA in primary reactor coolant system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae-Hyeong; Yun, Jong-Il [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    The performance with integrity of nuclear power plants is highly influenced by the presence of the corrosion products. The deposition of corrosion products in the steam generator is the one of the main concerns of power plants. The quantification of corrosion products is considered of importance. In this study, we applied the spectrophotometric method to detect metal ions such as iron, cobalt, nickel, copper, and zinc, which are major elements of structural material of the plant. In particular, the chemical complexation of those divalent metal ions with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) provides high molar absorptivity. For the simultaneous determination of metal ions, a partial least square (PLS) regression method was applied. In the present work, the complexation of Br-PADAP with divalent metal ions (iron, cobalt, nickel, copper and zinc) was studied. The PLS regression method was successfully applied for simultaneous elemental detection in multi-element systems. These results suggests that the method is very ample to detect corrosion products in nuclear power plants.

  15. Approaching the limit of Cu(II)/Cu(I) mixed valency in a Cu(I)Br2-N-methylquinoxalinium hybrid compound.

    Science.gov (United States)

    Leblanc, Nicolas; Sproules, Stephen; Pasquier, Claude; Auban-Senzier, Pascale; Raffy, Helene; Powell, Annie K

    2015-08-18

    A novel 1D hybrid salt (MQ)[CuBr2]∞ (MQ = N-methylquinoxalinium) is reported. Structural, spectroscopic and magnetic investigations reveal a minimal Cu(II) doping of less than 0.1%. However it is not possible to distinguish Cu(I) and Cu(II). The unusually close packing of the organic moieties and the dark brown colour of the crystals suggest a defect electronic structure.

  16. 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.

  17. Effects of CuBr addition to CH3NH3PbI3(Cl) perovskite photovoltaic devices

    Science.gov (United States)

    Oku, Takeo; Ohishi, Yuya; Tanaka, Hiroki

    2018-01-01

    Effects of CuBr addition to perovskite CH3NH3PbI3(Cl) precursor solutions on photovoltaic properties were investigated. The CH3NH3Pb(Cu)I3(Cl,Br)-based photovoltaic devices were fabricated by a spin-coating technique, and the microstructures of the devices were investigated by X-ray diffraction, optical microscopy and scanning electron microscopy. Current density-voltage characteristics were improved by a small amount of CuBr addition, which resulted in improvement of the conversion efficiencies of the devices. The structure analysis showed decrease of unit cell volume and increase of Cu/Br composition by the CuBr addition, which would indicate the Cu/Br substitution at the Pb/I sites in the perovskite crystal, respectively.

  18. 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...... activity and acidity was lower for promoted catalysts than for unpromoted catalysts. In the heteropoly acid promoted catalysts the SCR active Cu and Fe metals were protected from potassium poisons by bonding of the potassium to the Brønsted acid centres. Thus heteropoly acid promoted catalysts might...... be suitable for biomass fired power plant SCR applications....

  19. Ground state magnetic properties of Fe nanoislands on Cu(111)

    International Nuclear Information System (INIS)

    Kishi, Tomoya; David, Melanie; Nakanishi, Hiroshi; Kasai, Hideaki; Dino, Wilson Agerico; Komori, Fumio

    2005-01-01

    We investigate magnetic properties of Fe nanoislands on Cu(111) in the relaxed structure within the density functional theory. We observe that the nanoislands exhibit the ferromagnetic properties with large magnetic moment. We find that the change in the magnetic moment of each Fe atom is induced by deposition on Cu(111) and structure relaxation of Fe nanoislands. Moreover, we examine the stability of ferromagnetic states of Fe nanoislands by performing the total energy calculations. (author)

  20. 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...

  1. 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.

  2. New insight on the local structure of Cu2+ ion in the solution of CuBr2 by EXAFS studies

    International Nuclear Information System (INIS)

    Yu Meijuan; Chu Wangsheng; Chen Xing; Wu Ziyu

    2009-01-01

    CuBr 2 solutions at different concentrations were studied by extended X-ray absorption fine structure (EXAFS) at the Cu K edge. In the saturated solution Cu 2+ ions have chemical bonds with 3.0 oxygen atoms and 0.9 Br ion at about 1.96 A and 2.42 A, respectively. It indicates that the CuBr 4 -2 configuration exists with a ratio of 25% under this condition. In the dilute solutions no evidence of Br ions contributions in the first shell around Cu 2+ ions occurs. The almost identical X-ray absorption near edge structure (XANES) and EXAFS characters address similar local environments around Cu 2+ in agreement with results of the EXAFS fit taking into account only the contributions of Cu-O bonds.

  3. New insight on the local structure of Cu{sup 2+} ion in the solution of CuBr{sub 2} by EXAFS studies

    Energy Technology Data Exchange (ETDEWEB)

    Yu Meijuan; Chu Wangsheng; Chen Xing; Wu Ziyu, E-mail: wuzy@ustc.edu.c [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049 (China)

    2009-11-15

    CuBr{sub 2} solutions at different concentrations were studied by extended X-ray absorption fine structure (EXAFS) at the Cu K edge. In the saturated solution Cu{sup 2+} ions have chemical bonds with 3.0 oxygen atoms and 0.9 Br ion at about 1.96 A and 2.42 A, respectively. It indicates that the CuBr{sub 4}{sup -2} configuration exists with a ratio of 25% under this condition. In the dilute solutions no evidence of Br ions contributions in the first shell around Cu{sup 2+} ions occurs. The almost identical X-ray absorption near edge structure (XANES) and EXAFS characters address similar local environments around Cu{sup 2+} in agreement with results of the EXAFS fit taking into account only the contributions of Cu-O bonds.

  4. Inter ionic pair potentials for molten copper halides CuX (X=Br, I)

    International Nuclear Information System (INIS)

    Canan, C.

    2004-01-01

    In this work, the inter-ionic pair interactions of molten CuBr and Cu I are described with three different form of the rigid ion model potentials (RIM) using i) the functional form originally proposed by Vasishta and Rahman ii) the form used Madden and coworkers which is include the polarization contributions iii) the form parameterizied by Tatlipinar et al. The capability of these potentials have been discussed with each other by calculating the static liquid structure. We present the results of the partial pair distributions for molten CuBr at 810K and for molten Cul at 940K comparing with experimental data. The structural calculations are performed by solving the numerically the hypemetted chain approximate theory of liquids

  5. 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.

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

    International Nuclear Information System (INIS)

    Canellas, C.G.L.; Carvalho, S.M.F.; Anjos, M.J.; Lopes, R.T.

    2012-01-01

    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: ► Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. ► It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. ► There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. ► The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

  7. Measurement of thermoelectric power of Fe-Cu binary alloys

    International Nuclear Information System (INIS)

    Joubouji, Katsuo

    2007-01-01

    In INSS, non-destructive evaluation (NDE) of irradiation embrittlement of low alloy steel using thermoelectric power (TEP) measurement has been considered, as well as NDE of thermal aging of cast duplex stainless steel which has been studied in recent years. Material degradation is evaluated based on a relation between progress of the degradation and change in TEP due to change in material structure caused by the degradation event. So it is necessary for NDE of irradiation embrittlement to measure the change in TEP due to precipitation of Cu contained as an impurity, which is known as one of the reasons for the embrittlement. In this study, TEP of Fe-Cu binary alloys with different Cu content was measured for investigation of the relationship between TEP of the alloys and Cu content. In addition, appropriateness of measuring TEP of Fe-Cu binary alloy in the same way to measure TEP of duplex stainless steel was examined. It was found that increment of Cu contained in the alloys changed TEP in a negative direction and the rate was evaluated as -6.6μV/K/wt%Cu. There were the cases that it took 20 minutes for measurement values to become stable in measurement of Fe-Cu binary alloys. It was much longer than the time taken in measurement of duplex stainless steel. So the measurement time per a point was extended to 60 minutes in case of Fe-Cu binary alloys. (author)

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

    KAUST Repository

    Wille, Catharina Gabriele; Al-Kassab, Talaá t; Kirchheim, Reiner

    2011-01-01

    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

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

    NARCIS (Netherlands)

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

    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

  10. 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)

  11. Exchange correlation length and magnetoresistance in Fe-Cu and Fe-Cu-Ni melt-spun ribbons

    International Nuclear Information System (INIS)

    El Ghannami, M.; Gomez-Polo, C.; Rivero, G.; Hernando, A.

    1994-01-01

    The magnetic properties of Fe 30 Cu 70 melt-spun ribbons are reported for the first time. In the as-cast state, the microstructure consists of b.c.c.-Fe grains immersed in a Cu-rich matrix. However, the addition of a small percentage of Ni gives rise to the appearance of new Cu-Fe-Ni phases. Under suitable thermal treatments, the microstructure of both alloys evolves towards a complete phase segregation in b.c.c-Fe and f.c.c.-Cu immiscibles phases. The temperature dependence of the magnetic properties is analysed and related to the microstructural changes produced during the thermal treatments. Remarkable magneto-resistance effects have been observed in both as-cast alloys, with maximum values of the order of 6% at low measuring temperatures. (orig.)

  12. 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.

  13. Photoelectron diffraction of magnetic ultrathin films: Fe/Cu(001)

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, J.G. (Lawrence Livermore National Lab., CA (USA)); Wagner, M.K. (Wisconsin Univ., Madison, WI (USA). Dept. of Chemistry); Guo, X.Q.; Tong, S.Y. (Wisconsin Univ., Milwaukee, WI (USA). Dept. of Physics)

    1991-01-03

    The preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6{Angstrom} between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dependent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s os near-monolayer Fe/Cu(001). 18 refs., 10 figs.

  14. Effect of interface intermixing on giant magnetoresistance in NiFe/Cu and Co/NiFe/Co/Cu multilayers

    International Nuclear Information System (INIS)

    Nagamine, L.C.C.M.; Biondo, A.; Pereira, L.G.; Mello, A.; Schmidt, J.E.; Chimendes, T.W.; Cunha, J.B.M.; Saitovitch, E.B.

    2003-01-01

    This article reports on the important influence of the spontaneously built-in paramagnetic interfacial layers on the magnetic and magnetoresistive properties of NiFe/Cu and Co/NiFe/Co/Cu multilayers grown by magnetron sputtering. A computational simulation, based on a semiclassical model, has been used to reproduce the variations of the resistivity and of the magnetoresistance (MR) amplitude with the thickness of the NiFe, Cu, and Co layers. We showed that the compositionally intermixed layers at NiFe/Cu interfaces, which are paramagnetic, reduce the flow of polarized electrons and produce a masking on the estimated mean-free path of both types of electrons due to the reduction of their effective values, mainly for small NiFe thickness. Moreover, the transmission coefficients for the electrons decrease when Fe buffer layers are replaced by NiFe ones. This result is interpreted in terms of the variations of the interfacial intermixing and roughness at the interfaces, leading to an increase of the paramagnetic interfacial layer thickness. The effect provoked by Co deposition at the NiFe 16 A/Cu interfaces has also been investigated. The maximum of the MR amplitudes was found at 5 A of Co, resulting in the quadruplication of the MR amplitude. This result is partially attributed to the interfacial spin-dependent scattering due to the increase of the magnetic order at interfaces. Another effect observed here was the increase of the spin-dependent scattering events in the bulk NiFe due to a larger effective NiFe thickness, since the paramagnetic interfacial layer thickness is decreased

  15. The interaction between dietary Fe, Cu and stress in Cu-67 retention and serum ceruloplasmin (Cp) activity in rats

    International Nuclear Information System (INIS)

    Pellett, L.; Kattelmann, K.; Zinn, K.; Trokey, D.; Forrester, I.; Gordon, D.T.

    1991-01-01

    The objectives of the study were to determine the effects of dietary Fe and stress on Cu-67 retention and serum Cp activity in the rat. A 2 x 2 x 2 factorial arrangement of treatments was utilized. Male Sprague Dawley weanling rats were fed AIN-76 diets ad lib containing 0.8 ppm Cu (CuD) or 5.7 ppm Cu (CuA) with 22.5 ppm Fe (FeA) or 280 ppm Fe (FeE). After 19 days, one-half of the animals of each treatment were stressed by an intramuscular injection of 0.1 ml turpentine/100 gm body weight. Forty-eight hours later, animals were gavaged with Cu-67 and counted over a 7 day period in a whole body high resolution gamma counter. Cu-67 retention was 20% higher in CuD rats compared to CuA rats. There were no significant effects caused by Fe or stress or the interaction between these variables on Cu-67 retention. In rats fed FeE-CuA diets, serum Cp activity was significantly depressed compared to rats fed FeA-CuA diets. These reductions in the acute phase protein Cp, were 85% and 70% in nonstressed and stressed rats, respectively. The results of this study suggest that the negative interaction effects of excess Fe on Cu utilization does not occur at the site of Cu absorption, but within the body and specifically in the liver

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-15

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  18. Role of Cu During Sintering of Fe0.96Cu0.04 Nanoparticles

    Science.gov (United States)

    Sivaprahasam, D.; Sriramamurthy, A. M.; Bysakh, S.; Sundararajan, G.; Chattopadhyay, K.

    2018-04-01

    Nanoparticle agglomerates of passivated Fe ( n-Fe) and Fe0.96Cu0.04 ( n-Fe0.96Cu0.04), synthesized through the levitational gas condensation (LGC) process, were compacted and sintered using the conventional powder metallurgy method. The n-Fe0.96Cu0.04 agglomerates produced lower green density than n-Fe, and when compacted under pressure beyond 200 MPa, they underwent lateral cracking during ejection attributed to the presence of a passive oxide layer. Sintering under dynamic hydrogen atmosphere can produce a higher density of compact in n-Fe0.96Cu0.04 in comparison to n-Fe. Both the results of dilatometry and thermogravimetric (TG) measurements of the samples under flowing hydrogen revealed enhancement of the sintering process as soon as the reduction of oxide layers could be accomplished. The shrinkage rate of n-Fe0.96Cu0.04 reached a value three times higher than n-Fe at a low temperature of 723 K (450 °C) during heating. This enhanced shrinkage rate was the manifestation of accumulation of Cu at the surface of the particles. The formation of a thin-surface melted layer enriched with copper during heating to isothermal holding facilitated as a medium of transport for diffusion of the elements. The compacts produced by sintering at 773 K (500 °C), with relative density 82 pct, were found to be unstable and oxidized instantly when exposed to ambient atmosphere. The stable compacts of density more than 92 pct with 300- to 450-nm grain size could only be produced when sintering was carried out at 973 K (700 °C) and beyond. The 0.22 wt pct residual oxygen obtained in the sintered compact is similar to what is used for conventional ferrous powder metallurgy products.

  19. Electric and magnetic properties of the stage-2 FeBr{sub 2} graphite intercalation compound

    Energy Technology Data Exchange (ETDEWEB)

    Dube, P A; Barati, M; Ummat, P K; Luke, G; Datars, W R [Department of Physics and Astronomy, McMaster University, Hamilton, ON (Canada)

    2003-01-22

    The stage-2 FeBr{sub 2} graphite intercalation compound (GIC) was prepared by reacting FeBr{sub 2} powder and highly oriented pyrolytic graphite in a bromine atmosphere at 500 deg. C for 40 weeks. The dc magnetization, ac susceptibility, specific heat, resistivity and Hall effect were measured. The GIC is paramagnetic at temperatures above 14.5 K. There is short-range ordering at 14.5 K and longer-range magnetic ordering at 8.5 K. There is a spin glass phase below 3.2 K in which the ac susceptibility is frequency dependent. The in-plane and c-axis resistivities result from in-plane and out-of-plane electron-phonon scattering. The Hall coefficient is independent of temperature between 4.2 and 300 K and is explained by the single-carrier model.

  20. Electric and magnetic properties of the stage-2 FeBr2 graphite intercalation compound

    International Nuclear Information System (INIS)

    Dube, P A; Barati, M; Ummat, P K; Luke, G; Datars, W R

    2003-01-01

    The stage-2 FeBr 2 graphite intercalation compound (GIC) was prepared by reacting FeBr 2 powder and highly oriented pyrolytic graphite in a bromine atmosphere at 500 deg. C for 40 weeks. The dc magnetization, ac susceptibility, specific heat, resistivity and Hall effect were measured. The GIC is paramagnetic at temperatures above 14.5 K. There is short-range ordering at 14.5 K and longer-range magnetic ordering at 8.5 K. There is a spin glass phase below 3.2 K in which the ac susceptibility is frequency dependent. The in-plane and c-axis resistivities result from in-plane and out-of-plane electron-phonon scattering. The Hall coefficient is independent of temperature between 4.2 and 300 K and is explained by the single-carrier model

  1. Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu ...

    Indian Academy of Sciences (India)

    The diameter of wires can be easily varied by pore size of alumina, ranging ... saturated HgCl2 solution to remove the remaining Al, and then dipped in 5 wt% ... for NiFe alloy it is 1.3 V, that is higher than for Ni/Cu nanowires to diminish Cu.

  2. Chemical vapour transport of pyrite (FeS 2) with halogen (Cl, Br, I)

    Science.gov (United States)

    Fiechter, S.; Mai, J.; Ennaoui, A.; Szacki, W.

    1986-12-01

    A systematic study of chemical vapour transport (CVT) of pyrite with halogen, hydrogen halides and ammonium halides as transporting agents has shown that the transport with chlorine and bromine in a temperature gradient Δ T = 920-820 K yields the highest transport rates (˜6 mg/h) with crystals up to 5 mm edge length. Computing thermochemical equilibria and flux functions in the system Fe-S-Hal (Hal = Cl, Br, I) it has been confirmed that the transport velocity of pyrite is limited by the concentration of FeHal 2 in the vapour phase, the equilibrium position between FeHal 2(g) and FeHal 3(g) and the flux directions of the iron gas species.

  3. Positron emission intensities in the decay of 64Cu, 76Br and 124I

    International Nuclear Information System (INIS)

    Qaim, S.M.; Bisinger, T.; Hilgers, K.; Nayak, D.; Coenen, H.H.

    2007-01-01

    The relatively long-lived positron emitters 64 Cu (t 1/2 = 12.7 h), 76 Br (t 1/2 = 16.2 h) and 124 I (t 1/2 = 4.18 d) are finding increasing applications in positron emission tomography (PET). For precise determination of their positron emission intensities, each radionuclide was prepared via a charged particle induced reaction in a ''no-carrier-added'' form and with high radionuclidic purity. It was then subjected to γ-ray and X-ray spectroscopy as well as to anticoincidence beta and γγ-coincidence counting. The positron emission intensities measured were: 64 Cu (17.8 ± 0.4)%, 76 Br (58.2 ± 1.9)% and 124 I (22.0 ± 0.5)%. The intensity of the weak 1346 keV γ-ray emitted in the decay of 64 Cu was determined as (0.54 ± 0.03)%. Some implications of the precisely determined nuclear data are discussed. (orig.)

  4. Lead-Free MA2CuCl(x)Br(4-x) Hybrid Perovskites.

    Science.gov (United States)

    Cortecchia, Daniele; Dewi, Herlina Arianita; Yin, Jun; Bruno, Annalisa; Chen, Shi; Baikie, Tom; Boix, Pablo P; Grätzel, Michael; Mhaisalkar, Subodh; Soci, Cesare; Mathews, Nripan

    2016-02-01

    Despite their extremely good performance in solar cells with efficiencies approaching 20% and the emerging application for light-emitting devices, organic-inorganic lead halide perovskites suffer from high content of toxic, polluting, and bioaccumulative Pb, which may eventually hamper their commercialization. Here, we present the synthesis of two-dimensional (2D) Cu-based hybrid perovskites and study their optoelectronic properties to investigate their potential application in solar cells and light-emitting devices, providing a new environmental-friendly alternative to Pb. The series (CH3NH3)2CuCl(x)Br(4-x) was studied in detail, with the role of Cl found to be essential for stabilization. By exploiting the additional Cu d-d transitions and appropriately tuning the Br/Cl ratio, which affects ligand-to-metal charge transfer transitions, the optical absorption in this series of compounds can be extended to the near-infrared for optimal spectral overlap with the solar irradiance. In situ formation of Cu(+) ions was found to be responsible for the green photoluminescence of this material set. Processing conditions for integrating Cu-based perovskites into photovoltaic device architectures, as well as the factors currently limiting photovoltaic performance, are discussed: among them, we identified the combination of low absorption coefficient and heavy mass of the holes as main limitations for the solar cell efficiency. To the best of our knowledge, this is the first demonstration of the potential of 2D copper perovskite as light harvesters and lays the foundation for further development of perovskite based on transition metals as alternative lead-free materials. Appropriate molecular design will be necessary to improve the material's properties and solar cell performance filling the gap with the state-of-the-art Pb-based perovskite devices.

  5. Effect of Soil Parameters on the Kinetics of the Displacement of Fe from FeEDDHA Chelates by Cu

    NARCIS (Netherlands)

    Schenkeveld, W.D.C.; Reichwein, A.M.; Temminghoff, E.J.M.; Riemsdijk, van W.H.

    2012-01-01

    In soil application, o,o-FeEDDHA (iron (3+) ethylene diamine-N,N'-bis(2-hydroxy phenyl acetic acid) complex) is the active ingredient of FeEDDHA chelate-based Fe fertilizers. The effectiveness of o,o-FeEDDHA is potentially compromised by the displacement of Fe from FeEDDHA by Cu. The actual impact

  6. 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.

  7. Anomaly observed in Moessbauer spectra near the neel temperature of FeBr sub 2

    CERN Document Server

    Naili Di

    2003-01-01

    In several decades, iron(II) bromide (FeBr sub 2) has been investigated as a typical Ising-type antiferromagnet by several kinds of experimental techniques. By the Moessbauer measurements, it was normally observed that only the magnetic spectrum appeared just below Neel temperature in FeBr sub 2. However, we found the anomalous spectra, in which paramagnetic component coexisted with magnetic one near Neel temperature. For two kinds of single crystal FeBr sub 2 samples, IM and IIM, we determined the Moessbauer parameters of the observed spectra by the computer analyses: the relative absorption intensity I sub p of the paramagnetic component to the total absorption area of the best fitting spectrum and the value of the hyperfine field H sub h sub f of the magnetic component and values of the quadrupole splitting 1/2 centre dot e sup 2 qQ of the magnetic and the paramagnetic components. The temperature variation of H sub h sub f is unique and the same as that observed for the sample in which the anomaly was not ...

  8. Moessbauer spectroscopy of Fe-Mn-Cu alloys

    International Nuclear Information System (INIS)

    Paduani, Clederson; Krause, Joao Carlos; Yoschida, M.I. Soares

    2004-01-01

    Full text: Although a continuous series of solid solutions exists between Cu and Mn, Fe and Cu are miscible only a few percent at higher temperatures. In moderately concentrated Cu-Mn alloys the Mn moments are bound to the long ranged antiferromagnetic order and the perpendicular components form an X-Y spin glass. Copper alloys are largely employed in various industrial applications. In this work we study the magnetic properties of iron-rich disordered Fe-Mn-Cu alloys with the bcc structure with the experimental techniques of X-ray diffraction (XRD), Moessbauer spectroscopy (MS) and thermogravimetry (TGA). We investigate the formation of a solid solution with the bcc structure as well as the effect of the composition on the structural and magnetic properties of these alloys. A Rietveld analysis of the XRD diffractograms indicate that all prepared samples are single phase and are well crystallized with a bcc structure. (author)

  9. Treatment of reverse osmosis (RO) concentrate by the combined Fe/Cu/air and Fenton process (1stFe/Cu/air-Fenton-2ndFe/Cu/air).

    Science.gov (United States)

    Ren, Yi; Yuan, Yue; Lai, Bo; Zhou, Yuexi; Wang, Juling

    2016-01-25

    To decompose or transform the toxic and refractory reverse osmosis (RO) concentrate and improve the biodegradability, 1stFe/Cu/air-Fenton-2ndFe/Cu/air were developed to treat RO concentrate obtained from an amino acid production plant in northern China. First, their operating conditions were optimized thoroughly. Furthermore, 5 control experiments were setup to confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and synergistic reaction between Fe/Cu/air and Fenton. The results suggest that the developed method could obtain high COD removal (65.1%) and BOD5/COD ratio (0.26) due to the synergistic reaction between Fe/Cu/air and Fenton. Under the optimal conditions, the influent and effluent of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and 5 control experiments were analyzed by using UV, FTIR, EEM and LC, which confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air. Therefore, the developed method in this study is a promising process for treatment of RO concentrate. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. 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......-dimensional fashion. Preliminary model calculations for the Cu2Te2O5Br2 system lead to the same conclusion. Udgivelsesdato: 7. Januar...

  11. Structural investigation of Fe(Cu)ZrB amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Duhaj, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Matko, I. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Svec, P. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav; Sitek, J. [Department of Nuclear Physics and Technology, Slovak Technical University, 81219 Bratislava (Slovakia); Janickovic, D. [Slovenska Akademia Vied, Bratislava (Slovakia). Fyzikalny Ustav

    1996-07-01

    The crystallization process in Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe{sub 86}(Cu{sub 1})Zr{sub 7}B{sub 6} and Fe{sub 87}Zr{sub 7}B{sub 6} alloys. In both alloys the first crystallization begins with the formation of nanocrystalline {alpha}-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of {alpha}-Fe and dispersed Fe{sub 23}Zr{sub 6} phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  12. Structural investigation of Fe(Cu)ZrB amorphous alloy

    International Nuclear Information System (INIS)

    Duhaj, P.; Janickovic, D.

    1996-01-01

    The crystallization process in Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 is investigated using the methods of transmission electron microscopy, electron and X-ray diffraction and resistometry. Two crystallization reactions take place during thermal annealing of amorphous Fe 86 (Cu 1 )Zr 7 B 6 and Fe 87 Zr 7 B 6 alloys. In both alloys the first crystallization begins with the formation of nanocrystalline α-Fe at temperature to approximately 800 K. The second crystallization starts above 1000 K; the nanocrystalline phase dissolves and together with the remaining amorphous matrix form rough grains of α-Fe and dispersed Fe 23 Zr 6 phases. From Moessbauer spectroscopy it seems that there exist two neighbourhoods of Fe atoms in the amorphous structure. One of them is characterized by low Zr content and is responsible for the high-field component of the hyperfine field distribution p(H). The second one is rich in Zr and B and is responsible for the low-field component of p(H). This is in accord with the observation of two crystallization steps separated by a large interval of temperatures due to the existence of two chemically different regions or clusters. (orig.)

  13. Minor-Cu doped soft magnetic Fe-based FeCoBCSiCu amorphous alloys with high saturation magnetization

    Science.gov (United States)

    Li, Yanhui; Wang, Zhenmin; Zhang, Wei

    2018-05-01

    The effects of Cu alloying on the amorphous-forming ability (AFA) and magnetic properties of the P-free Fe81Co5B11C2Si1 amorphous alloy were investigated. Addition of ≤ 1.0 at.% Cu enhances the AFA of the base alloy without significant deterioration of the soft magnetic properties. The Fe80.5Co5B11C2Si1Cu0.5 alloy with the largest critical thickness for amorphous formation of ˜35 μm possesses a high saturation magnetization (Bs) of ˜1.78 T, low coercivity of ˜14.6 A/m, and good bending ductility upon annealing in a wide temperature range of 513-553 K with maintaining the amorphous state. The fabrication of the new high-Fe-content Fe-Co-B-C-Si-Cu amorphous alloys by minor doping of Cu gives a guideline to developing high Bs amorphous alloys with excellent AFA.

  14. NMR evidence of charge fluctuations in multiferroic CuBr2

    Science.gov (United States)

    Wang, Rui-Qi; Zheng, Jia-Cheng; Chen, Tao; Wang, Peng-Shuai; Zhang, Jin-Shan; Cui, Yi; Wang, Chao; Li, Yuan; Xu, Sheng; Yuan, Feng; Yu, Wei-Qiang

    2018-03-01

    We report combined magnetic susceptibility, dielectric constant, nuclear quadruple resonance (NQR), and zero-field nuclear magnetic resonance (NMR) measurements on single crystals of multiferroics CuBr2. High quality of the sample is demonstrated by the sharp magnetic and magnetic-driven ferroelectric transition at {T}{{N}}={T}{{C}}≈ 74 K. The zero-field 79Br and 81Br NMR are resolved below T N. The spin-lattice relaxation rates reveal charge fluctuations when cooled below 60 K. Evidences of an increase of NMR linewidth, a reduction of dielectric constant, and an increase of magnetic susceptibility are also seen at low temperatures. These data suggest an emergent instability which competes with the spiral magnetic ordering and the ferroelectricity. Candidate mechanisms are discussed based on the quasi-one-dimensional nature of the magnetic system. Project supported by the Ministry of Science and Technology of China (Grant No. 2016YFA0300504), the National Natural Science Foundation of China (Grant No. 11374364), the Fundamental Research Funds for the Central Universities of China, and the Research Funds of Renmin University, China (Grant No. 14XNLF08).

  15. 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...

  16. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    Comparison of trace element contamination levels (Cu, Zn, Fe, Cd and Pb) in the soft tissues of the gastropods Tympanotonus fuscatus fuscatus and Tf radula collected in the Ebrié Lagoon (Côte d'Ivoire): Evidence of the risks linked to linked to lead and.

  17. Comparison of trace element contamination levels (Cu, Zn, Fe, Cd ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... Chemical analysis of the trace elements in the soft tissues. The trace elements of interest (Cu, Zn, Fe, Pb, Cd) were then determined in the digested solutions, using Thermoelemental type. M6 brand of an atomic absorption Spectrometer equipped with a flame operated atomisation system and a deuterium ...

  18. High strength-high conductivity Cu-Fe composites produced by powder compaction/mechanical reduction

    Science.gov (United States)

    Verhoeven, J.D.; Spitzig, W.A.; Gibson, E.D.; Anderson, I.E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an ''in-situ'' Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite. 5 figures.

  19. High strength-high conductivity Cu--Fe composites produced by powder compaction/mechanical reduction

    Science.gov (United States)

    Verhoeven, John D.; Spitzig, William A.; Gibson, Edwin D.; Anderson, Iver E.

    1991-08-27

    A particulate mixture of Cu and Fe is compacted and mechanically reduced to form an "in-situ" Cu-Fe composite having high strength and high conductivity. Compaction and mechanical reduction of the particulate mixture are carried out at a temperature and time at temperature selected to avoid dissolution of Fe into the Cu matrix particulates to a harmful extent that substantially degrades the conductivity of the Cu-Fe composite.

  20. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    OpenAIRE

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-01-01

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these allo...

  1. 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.

  2. Characterization of the LiSi/CsBr-LiBr-KBr/FeS(2) System for Potential Use as a Geothermal Borehole Power Source

    International Nuclear Information System (INIS)

    GUIDOTTI, RONALD A.; REINHARDT, FREDERICK W.

    1999-01-01

    We are continuing to study the suitability of modified thermal-battery technology as a potential power source for geothermal borehole applications. Previous work focused on the LiSi/FeS(sub 2) couple over a temperature range of 350 C to 400 C with the LiBr-KBr-LiF eutectic, which melts at 324.5 C. In this work, the discharge processes that take place in LiSi/CsBr-LiBr-KBr eutectic/FeS(sub 2) thermal cells were studied at temperatures between 250 C and 400 C using pelletized cells with immobilized electrolyte. The CsBr-LiBr-KBr eutectic was selected because of its lower melting point (228.5 C). Incorporation of a quasi-reference electrode allowed the determination of the relative contribution of each electrode to the overall cell polarization. The results of single-cell tests and limited battery tests are presented, along with preliminary data for battery stacks tested in a simulated geothermal borehole environment

  3. 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

  4. Mechanical alloying in the Fe-Cu system

    DEFF Research Database (Denmark)

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

    1998-01-01

    The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility...... 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....

  5. Anomalous fast diffusion in Cu-NiFe nanolaminates.

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Alan F. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States). Energy Nanomaterials Dept.

    2017-09-01

    For this work, the decomposition of the one-dimensional composition wave in Cu-NiFe nanolaminate structures is examined using x-ray diffraction to assess the kinetics of phase decomposition. The anomalously high diffusivity value found for long-term aging at room temperature is attributed to the inherent nanostructure that features paths for short-circuit diffusion in nanolaminates as attributed to interlayer grain boundaries.

  6. 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...

  7. Ammonia synthesis on Au modified Fe(111) and Ag and Cu modified Fe(100) surfaces

    DEFF Research Database (Denmark)

    Lytken, Ole; Waltenburg, Hanne Neergaard; Chorkendorff, Ib

    2003-01-01

    In order to investigate any influence of steps and possible positive effects of making surface alloys the ammonia synthesis has been investigated over Au modified Fe(111) and Ag and Cu modified Fe(100) single crystals in the temperature range 603-773 K, using a system combining ultra-high vacuum...... and a high-pressure cell. Ammonia was synthesized from a stoichiometric (N-2:3H(2)) gas mixture at a pressure of 2 bar. By deposition of small amounts of An, the ammonia production activity of the Fe(1 1 1) surface can be enhanced. More important, for the gold modified surface, the reaction order in ammonia...

  8. 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

    profiles of two single Fe/Cu interfaces. The small deviations from this simple superposition are shown to be a consequence of quantum-well states confined within the paramagnetic spacer. This connection is confirmed by direct calculation of the state density. The results are of conceptual interest...

  9. Coercivity Recovery Effect of Sm-Fe-Cu-Al Alloy on Sm2Fe17N3 Magnet

    Science.gov (United States)

    Otogawa, Kohei; Asahi, Toru; Jinno, Miho; Yamaguchi, Wataru; Takagi, Kenta; Kwon, Hansang

    2018-03-01

    The potential of a Sm-Fe-Cu-Al binder for improvement of the magnetic properties of Sm2Fe17N3 was examined. Transmission electron microscope (TEM) observation of a Sm-Fe-Cu-Al alloy-bonded Sm2Fe17N3 magnet which showed high coercivity revealed that the Sm-Fe-Cu-Al alloy had an effect of removing the surface oxide layer of the Sm2 Fe17N3 grains. However, the Sm-Fe-Cu-Al binder was contaminated by carbon and nitrogen, which originated from the organic solvent used as the milling medium during pulverization. To prevent carbon and nitrogen contamination, the Sm-Fe- Cu-Al alloy was added directly on the surface of the Sm2Fe17N3 grains by sputtering. Comparing the recovered coercivity per unit amount of the added binder the uncontaminated binder-coated sample had a higher coercivity recovery effect than the milled binder-added sample. These results suggested that sufficient addition of the contamination-free Sm-Fe-Cu-Al binder has the possibility to reduce the amount of binder necessary to produce a high coercive Sm2Fe17N3 magnet.

  10. Room temperature deposition of amorphous p-type CuFeO2 and ...

    Indian Academy of Sciences (India)

    fabrication of CuFeO2/n-Si heterojunction by RF sputtering method. TAO ZHU1 ... Transparent conducting amorphous p-type CuFeO2 (CFO) thin film was prepared by radio-frequency ... Delafossite oxides CuMO2 (M is trivalent cation, such as.

  11. Virtual thermal expansion coefficient of Cu precipitated in the Fe95Cu5 alloy

    International Nuclear Information System (INIS)

    Koeszegi, L.; Somogyvari, Z.

    1999-01-01

    Complete text of publication follows. Precipitations on grain boundaries play very important role in the formation of material's characteristics like embrittlement, durability etc. It was already shown [1] that Cu precipitations are under different stress conditions than the bulk material. The situation is more complicated in the case when a construction is exposed to temperature changes as well. In that case not only the residual stresses during the fabrication but the different thermal expansion coefficients can produce additional problems. This situation was modelled using Fe 95 Cu 5 alloy where Cu precipitates on the grain boundaries. The alloy was produced by high-frequency melting and an extra heat treatment was used to produce a quasi-equilibrium state. Pure Cu was also measured to compare the behaviours. Cu(111) Bragg peak was measured at different temperatures by high resolution neutron diffraction. The measurements were carried out on the G5-2 spectrometer at LLB in Saclay. Measurements show that not only residual stress can be recognised on the Cu precipitates but the thermal expansion coefficient of these precipitates definitly differ from the ones of pure Cu. (author)

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)

    2016-06-13

    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.

  14. 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)

    Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T.; Bellido, Alfredo Victor B.; Anjos, Marcelino J.

    2011-01-01

    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 (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)

  15. 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)

  16. 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)

  17. 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.

  18. Transverse excitations in liquid Fe, Cu and Zn

    International Nuclear Information System (INIS)

    Hosokawa, S; Inui, M; Kajihara, Y; Tsutsui, S; Baron, A Q R

    2015-01-01

    Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering spectra of liquid Fe, Cu and Zn. From the analysis of current correlation functions, we concluded that TA excitation modes can experimentally be detected through the quasi-TA branches in the longitudinal current correlation spectra in these liquid metals. The microscopic elastic constants are estimated and a characteristic difference from macroscopic polycrystalline value was found in Poisson's ratio of liquid Fe, which shows an extremely softer value of ∼0.38 compared with the macroscopic value of ∼0.275. The lifetime of the TA modes were determined to be ∼0.45 ps for liquid Fe and Cu and ∼0.55 ps for liquid Zn, reflecting different interatomic correlations between liquid transition metals and non-transition metals. The propagation length of the TA modes are ∼0.85 nm in all of liquid metals, corresponding to the size of icosahedral or similar size of cages formed instantaneously in these liquid metals. (paper)

  19. CoFe Layers Thickness and Annealing Effect on the Magnetic Behavior of the CoFe/Cu Multilayer Nanowires

    Directory of Open Access Journals (Sweden)

    M. Ahmadzadeh

    2015-04-01

    Full Text Available CoFe/Cu multilayer nanowires were electrodeposited into anodic aluminum oxide templates prepared by a two-step mild anodization method, using the single-bath technique. Nanowires with 30 nm diameter and the definite lengths were obtained. The effect of CoFe layers thickness and annealing on the magnetic behavior of the multilayer nanowires was investigated. The layers thickness was controlled through the pulses numbers: 200, 260, 310,360 and 410 pulses were used to deposit the CoFe layers, while 300 pulse for the Cu layers. A certain increase in coercivity and squareness of CoFe/Cu multilayer nanowires observed with increasing the CoFe layer thickness and annealing improved the coercivity and decrease squareness of CoFe/Cu multilayer nanowires. First order reversal curves after annealed showed amount domains with soft magnetic phase, it also shows decreasing spreading of distribution function along the Hu axis after annealed

  20. Formation of Al70Cu20Fe10 icosahedral quasicrystal by mechanically alloyed method

    International Nuclear Information System (INIS)

    Yin Shilong; Bian Qing; Qian Liying; Zhang Aimei

    2007-01-01

    The structural evolutions of the mechanically alloyed ternary Al 70 Cu 20 Fe 10 powders with the milling time and the annealing treatment have been studied by X-ray diffraction (XRD), transmission electronic microscopy (TEM) and X-ray absorption fine-structure spectroscopy (XAFS) techniques. Results show that an Al 2 Cu compound forms with short-time milling, while a Cu 9 Al 4 compound forms with long-time milling. Fe can react with Al-Cu alloy by annealing treatment. Al 7 Cu 2 Fe compound with tetragonal structure or Al (Cu, Fe) solid solution with cubic structure may form at lower temperature, while a quasicrystal phase of Al 65 Cu 20 Fe 15 alloy may form at higher temperature

  1. Effect of solute Cu on ductile-to-brittle behavior of martensitic Fe-8% Ni alloy

    International Nuclear Information System (INIS)

    Junaidi Syarif; Tsuchiyama, Toshihiro; Takaki, Setsuo

    2007-01-01

    Effect of solute Cu on the ductile-to-brittle (DBT) behaviour of martensitic Fe-8mass%Ni alloy is investigated to understand the effect of solute Cu on mechanical properties of martensitic steel. The DBT behaviours of the Fe-8mass%Ni and the Fe-8mass%Ni-1mass%Cu alloys are almost the same. It is thought to be due to disappearance of the solid solution softening in the martensitic Fe-8mass%Ni-Cu alloys. The solute Cu gives small influence on temperature and strain rate dependences of yield stress and suppressing the twin deformation at lower temperature in the martensitic Fe-8mass%Ni alloy. Therefore, the DBT temperature of the martensitic Fe-8mass%Ni-Cu alloy was not shifted to lower side. (author)

  2. A study of a stable Al-Cu-Fe quasicrystal in solid and liquid state

    International Nuclear Information System (INIS)

    Chen Lifan; Chen Xishen

    1992-01-01

    A stable Al 65 Cu 20 Fe 15 quasicrystal with an icosahedral structure is studied in solid and liquid state. It is found that the icosahedral phase in Al 65 Cu 20 Fe 15 alloy does not grow directly from the pure liquid state, but rather forms between monoclinic Al 13 Fe 4 and residual liquid state at 865degC. The melting point of the Al 65 Cu 20 Fe 15 icosahedral quasicrystal occurs at 865degC and that of the Al 65 Cu 20 Fe 15 alloy occurs at 1008degC. Moreover, the monoclinic Al 13 Fe 4 is transformed into the icosahedral phase easily at the temperature of 845degC. The icosahedral quasicrystal in Al 65 Cu 20 Fe 15 alloy has a high thermal stability even at 950degC. Above 950degC, the icosahedral structure tends to an amorphous structure. (orig.)

  3. Magneto-optical response of Cu/NiFe/Cu nanostructure under surface plasmon resonance

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodi, S. [Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, 87317 (Iran, Islamic Republic of); Moradi, M., E-mail: m.moradi@kashanu.ac.ir [Institute of Nanoscience and Nanotechnology, University of Kashan, Kashan, 87317 (Iran, Islamic Republic of); Mohseni, S.M. [Department of Physics, Shahid Beheshti University, Evin, Tehran, 19839 (Iran, Islamic Republic of)

    2016-12-15

    In this paper, we present theoretical and experimental studies about the surface plasmon resonance effects on the magneto-optical activity of Cu/NiFe/Cu nanostructures as a function of layers thickness and light incident angle. Device fabrication was done by an oblique deposition technique with RF magnetron sputtering to carefully cover fine step thickness variation of all constituted layers. Angular dependent transverse Kerr response of samples was measured in the Kretschmann configuration at a fixed wavelength of 632 nm. At an optimum layer thickness and incident angle, significant amplification of the transverse Kerr effect was observed. Enhancement in the transverse Kerr effect can be realized by hybridization of surface plasmon excitation and cavity resonance in the plasmonic nanostructure. Experimental results were in qualitative agreement with modeling based on the 4×4 transfer matrix formalism. - Highlights: • Large magneto-optical response in Cu/NiFe/Cu multilayer nanostructure is achieved. • Layer thickness and sequence are studied to find large transverse Kerr signal. • Hybridization of surface plasmon excitation and cavity resonance were done.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-30

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

  5. Quantitative trait loci controlling Cu, Ca, Zn, Mn and Fe content in ...

    Indian Academy of Sciences (India)

    of essential minerals (such as Fe, Zn etc), breeding mineral- efficient crops that produce .... and seven digenic interactions were identified for Cu, Ca,. Zn, Mn and Fe, .... Eva P. 1993 Cadmium, copper and lead in wild rice from central. Canada.

  6. Determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Lorenzo, Magdalena; Reyes, Arlyn; Blanco, Idania; Vasallo, Maria C

    2010-01-01

    The determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry was carried out. For 20 μL injected sample, calibration within the 0,5-25,0 mg. L -1 Ca; 0,25-5,0 mg. L -1 Cu, Pb and Cu intervals were established using the ratios Cu, Ca, Fe and Pb absorbance versus analyte concentration, respectively. Typical linear correlations of r = 0,999 were obtained. The proposed method was applied for the direct determination of Ca, Cu, Fe and Pb in sugar cane spirits, and in samples. The results obtained were in accordance to those obtained at 95% confidence level

  7. Josephson edge junctions on YBa2Cu3O7 thin films prepared with Br-ethanol etching

    International Nuclear Information System (INIS)

    Faley, M.I.; Poppe, U.; Daehne, U.; Goncharov, Yu.G.; Klein, N.; Urban, K.; Soltner, H.

    1993-01-01

    To produce damage-free edges is one of the main problems in the preparation of the Josephson edge-type junctions and interconnects in multilayer structures including high temperature superconductors. The commonly used ion beam etching has the disadvantages of the risk of contamination by redeposited material and structural damage to the surface of the edge. Vasquez et al and Gurvitch et al introduced a nonaqueous Br-ethanol etching for the preparation of clean surfaces of YBa 2 Cu 3 O 7 single crystals and thin films. We have developed a procedure of deep-UV-photolithography combined with nonaqueous Br-ethanol etching for the preparation of the Josephson edge-type junctions. Here we present the improvement of this method and report further results on the study of the electron transport properties of Josephson junctions with the edges of YBa 2 Cu 3 O 7 thin films produced by this technique. (orig.)

  8. NH3-SCR on Cu, Fe and Cu + Fe exchanged beta and SSZ-13 catalysts: Hydrothermal aging and propylene poisoning effects

    International Nuclear Information System (INIS)

    Wang, Aiyong; Wang, Yilin; Walter, Eric D.; Washton, Nancy M.

    2017-01-01

    Cu, Fe and Cu + Fe ion exchanged Beta and SSZ-13 catalysts were prepared by solution ion exchange using commercial NH 4 /Beta, and NH 4 /SSZ-13 that was prepared in-house. To study hydrothermal aging effects, Beta supported catalysts were aged hydrothermally at 700 °C and SSZ-13 supported catalysts were aged at 750 °C. In order to reveal the effects of Fe addition in the co-exchanged catalysts, these catalysts were characterized by means of powder X-ray diffraction (XRD), N 2 adsorption-desorption, electron paramagnetic resonance (EPR), 27 Al-nuclear magnetic resonance ( 27 Al-NMR) and propylene coking followed with temperature programmed reaction (TPR), and further tested with standard NH 3 -SCR with and without the presence of propylene. Collectively, the catalyst characterizations and reaction testing indicated minor beneficial effects of Fe addition in Cu,Fe/Beta, where NH 3 -SCR activity, N 2 selectivity and hydrothermal stability were all slightly improved. In contrast, Fe addition did not show apparent beneficial effects in low-temperature SCR for the Cu,Fe/SSZ-13 case. In conclusion, at elevated reaction temperatures, however, the presence of Fe indeed considerably improved NO conversion and N 2 selectivity for the hydrothermally aged Cu,Fe/SSZ-13 catalyst in the presence of propylene.

  9. Kinetic study of the annealing reactions in Cu-Ni-Fe alloys

    International Nuclear Information System (INIS)

    Donoso, E.

    2014-01-01

    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 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 3 phase. (Author)

  10. Structural features in icosahedral Al63Cu25Fe12

    International Nuclear Information System (INIS)

    Howell, R.H.; Solal, F.; Turchi, P.E.A.; Berger, C.; Calvayrac, Y.

    1991-01-01

    Since the discovery of a quasicrystalline phase in Al-Mn alloys a substantial amount of work has been done to understand the structural and physical properties of this new class of materials. More recently the discovery of a thermodynamically stable icosahedral phase in AlCuFe presents the opportunity to study pure quasicrystalline phases of high structural quality by eliminating known defects, especially phason disorder by conventional heat treatment. In particular it was shown that annealing treatments of as quenched samples resulted in a dramatic reduction in the width of the diffraction peaks associated with the elimination of as quenched defects, present in other quasicrystals. Positron annihilation lifetime measurements have a high sensitivity to intrinsic defects and positron annihilation radiation angular correlation measurements are well suited to measurements of electronic structure in systems where the defect effects do not dominate. We have measured positron annihilation lifetime and angular correlations on quasicrystalline samples of Al 63 Cu 25 Fe 12 in the pure icosahedral phase

  11. 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...

  12. Metastable Phase Separation and Concomitant Solute Redistribution of Liquid Fe-Cu-Sn Ternary Alloy

    International Nuclear Information System (INIS)

    Xiao-Mei, Zhang; Wei-Li, Wang; Ying, Ruan; Bing-Bo, Wei

    2010-01-01

    Liquid Fe-Cu-Sn ternary alloys with lower Sn contents are usually assumed to display a peritectic-type solidification process under equilibrium condition. Here we show that liquid Fe 47.5 Cu 47.5 Sn 5 ternary alloy exhibits a metastable immiscibility gap in the undercooling range of 51–329 K (0.19T L ). Macroscopic phase separation occurs once undercooling exceeds 196 K and causes the formation of a floating Fe-rich zone and a descending Cu-rich zone. Solute redistribution induces the depletion of Sn concentration in the Fe-rich zone and its enrichment in the Cu-rich zone. The primary Fe phase grows dendritically and its growth velocity increases with undercooling until the appearance of notable macrosegregation, but will decrease if undercooling further increases beyond 236 K. The microsegregation degrees of both solutes in Fe and Cu phases vary only slightly with undercooling. (condensed matter: structure, mechanical and thermal properties)

  13. Silicon induced Fe deficiency affects Fe, Mn, Cu and Zn distribution in rice (Oryza sativa L.) growth in calcareous conditions.

    Science.gov (United States)

    Carrasco-Gil, Sandra; Rodríguez-Menéndez, Sara; Fernández, Beatriz; Pereiro, Rosario; de la Fuente, Vicenta; Hernandez-Apaolaza, Lourdes

    2018-04-01

    A protective effect by silicon in the amelioration of iron chlorosis has recently been proved for Strategy 1 species, at acidic pH. However in calcareous conditions, the Si effect on Fe acquisition and distribution is still unknown. In this work, the effect of Si on Fe, Mn, Cu and Zn distribution was studied in rice (Strategy 2 species) under Fe sufficiency and deficiency. Plants (+Si or-Si) were grown initially with Fe, and then Fe was removed from the nutrient solution. The plants were then analysed using a combined approach including LA-ICP-MS images for each element of interest, the analysis of the Fe and Si concentration at different cell layers of root and leaf cross sections by SEM-EDX, and determining the apoplastic Fe, total micronutrient concentration and oxidative stress indexes. A different Si effect was observed depending on plant Fe status. Under Fe sufficiency, Si supply increased Fe root plaque formation, decreasing Fe concentration inside the root and increasing the oxidative stress in the plants. Therefore, Fe acquisition strategies were activated, and Fe translocation rate to the aerial parts was increased, even under an optimal Fe supply. Under Fe deficiency, +Si plants absorbed Fe from the plaque more rapidly than -Si plants, due to the previous activation of Fe deficiency strategies during the growing period (+Fe + Si). Higher Fe plaque formation due to Si supply during the growing period reduced Fe uptake and could activate Fe deficiency strategies in rice, making it more efficient against Fe chlorosis alterations. Silicon influenced Mn and Cu distribution in root. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  14. Formation of SmFe5(0001) ordered alloy thin films on Cu(111) single-crystal underlayers

    International Nuclear Information System (INIS)

    Yabuhara, Osamu; Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-01-01

    SmFe 5 (0001) single-crystal thin films are prepared by molecular beam epitaxy employing Cu(111) single-crystal underlayers on MgO(111) substrates. The Cu atoms diffuse into the Sm-Fe layer and substitute the Fe sites in SmFe 5 structure forming an alloy compound of Sm(Fe,Cu) 5 . The Sm(Fe,Cu) 5 film is more Cu enriched with increasing the substrate temperature. The Cu underlayer plays an important role in assisting the formation of the ordered phase.

  15. Formation of SmFe{sub 5}(0001) ordered alloy thin films on Cu(111) single-crystal underlayers

    Energy Technology Data Exchange (ETDEWEB)

    Yabuhara, Osamu; Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki [Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Kirino, Fumiyoshi, E-mail: yabuhara@futamoto.elect.chuo-u.ac.j [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, 12-8 Ueno-koen, Taito-ku, Tokyo 110-8714 (Japan)

    2010-01-01

    SmFe{sub 5}(0001) single-crystal thin films are prepared by molecular beam epitaxy employing Cu(111) single-crystal underlayers on MgO(111) substrates. The Cu atoms diffuse into the Sm-Fe layer and substitute the Fe sites in SmFe{sub 5} structure forming an alloy compound of Sm(Fe,Cu){sub 5}. The Sm(Fe,Cu){sub 5} film is more Cu enriched with increasing the substrate temperature. The Cu underlayer plays an important role in assisting the formation of the ordered phase.

  16. Stress impedance effect of FeCoSiB/Cu/FeCoSiB sandwich layers on flexible substrate

    International Nuclear Information System (INIS)

    Peng, B.; Zhang, W.L.; Liu, J.D.; Zhang, W.X.

    2011-01-01

    FeCoSiB/Cu/FeCoSiB sandwich layers were deposited on flexible substrate to develop flexible stress/strain sensors. The influence of stress on the impedance of the multilayers is reported. The results show that the variation of the impedance increases with the increase in deflection of the free end of the cantilever. A relative change in impedance of 6.4% is obtained in the FeCoSiB(1.5 μm)/Cu(0.25 μm)/FeCoSiB(1.5 μm) sandwich layers at 1 MHz with deflection of 2 mm. The stress impedance effects are sensitive to the frequency of the current and the thickness of both FeCoSiB and Cu layers. The stress impedance effect increases with the increase in the thickness of FeCoSiB or Cu layers. The stress impedance effect increases slightly with the increase in frequency and decreases with the further increase in frequency, which can be understood by the stress and frequency-dependent permeability of magnetic films. - Research highlights: → We deposited FeCoSiB/Cu/FeCoSiB multilayer on flexible substrate. → We studied the stress impedance effect of FeCoSiB/Cu/FeCoSiB multilayer. → Stress impedance effect increases with thickness of both FeCoSiB and Cu layer.→ Stress impedance effect is dependent on current frequency. → Results are understood using stress and frequency-dependent permeability.

  17. Status report on developing I-124, Pd-103, Tc-94m, Br-76 and Cu-64 radioisotopes at KIRAMS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H.; Kim, S. K.; Han, S. J.; Oh, T. H.; Kim, K. K.; Park, H.; Lee, J. S.; Jun, K. S. [KIRAMS, Seoul (Korea, Republic of)

    2005-07-01

    The decay characteristics of their radioisotopes such as I-124, Pd-103, Tc-94m, Br-76 and Cu-64 radionuclides produced by cyclotron have considered useful agents for diagnostic imaging or therapy. In order to increase the availability of the radionuclides, the investigation for the high capacity target design and simple procedures yielding high activities is being carried. Therefore, KIRAMS will lead researchers in nuclear medicine to access the feasibility of reliable production for enough quantities of several research radioisotopes using (p,xn) reactions. The quality and yield of products are evaluated theoretically from the excitation functions as a function of proton energies, target thickness, bombarding time, and growth time. Radionuclidic impurities are determined by gamma-spectrometer with high purity Germanium (HPGe) detector and the yields are read by ion chamber. Multi-millicuries of radioisotope I-124 (23% positron emission, half-life 4.2 days) is produced by 125-TeO2(p,2n)124-I reaction at the incident proton energy of 22 MeV. The production of carrier-free Pd-103 by the 103Rh(p,n)103Pd reaction with the 18 MeV proton beam. The electroplating method of Rh to Cu plate and recovery of rhodium from irradiated target fragments will be discussed. The thermal stability of Rh films on Cu plate will be tested for the mass production by increasing beam current up to 220uA with high-current cyclotron. For Cu-64, Tc-94m and Br-76 radionuclides, the target preparation and separating techniques are under developing. Our research project emphasis is in the development of routine methods for the production of Pd-103 radionuclide for brachytherapy seed and PET radionuclides, which include I-124, Tc-94m, Br-76 and Cu-64. In addition to the production of these radionuclides, we are developing novel radiopharmaceuticals utilizing these isotopes for both imaging and therapy.

  18. Experimental study of the spin density of metastable fcc ferromagnetic Fe-Cu alloys

    International Nuclear Information System (INIS)

    Bove, L. E.; Petrillo, C.; Sacchetti, F.; Mazzone, G.

    2000-01-01

    Magnetization density measurements on metastable Fe x Cu 1-x alloys at four compositions (x=20, 40, 50, and 60 at. %) and at 5 K temperature were carried out by means of polarized neutron diffraction. The samples were produced by high-energy ball milling and characterized by x-ray diffraction and fluorescence measurements. Additional bulk magnetization measurements were carried out on the two samples at high Fe concentration. Over the present concentration region, the Fe-Cu system is ferromagnetic and the four samples were found to be in the fcc phase. Fe-Cu is therefore a very suitable system to investigate the magnetic state of Fe in an fcc environment. Other than confirming that the Fe-Cu system is not a simple dilution alloy, the present results were compatible with a two-state model for fcc Fe--that is, two different coexisting electronic states associated with different magnetic moments and form factors

  19. Bonding in d9 complexes derived from EPR: Application to CuCl2-4, CuBr2-4, and CdCl2:Cu2+

    Science.gov (United States)

    Aramburu, J. A.; Moreno, M.

    1985-12-01

    In this work are reported the theoretical expressions for the [g], hyperfine, and superhyperfine (shf) tensors of a d9 square-planar complex within a molecular orbital (MO) scheme. These expressions include contributions arising from crystal field and charge transfer excitations calculated up to third and second order perturbations, respectively. This makes the present framework more general than those previously used. Through those expressions we have derived from the experimental EPR and optical data the MO coefficients corresponding to the valence b1g(x2-y2), b2g(xy), and eg(xz,yz) levels and also the core polarization contribution K to the hyperfine tensor for the systems CuCl2-4, CuBr2-4, and CdCl2:Cu2+. The 3d charge obtained for CuCl2-4 is equal to 0.61, 0.83, and 0.85 for the antibonding 3b1g, 2b2g, and 2eg levels, respectively. These figures are much closer to the Xα results by Bencini and Gatteschi [J. Am. Chem. Soc. 105, 5535 (1983)] than to those by Desjardins et al. [J. Am. Chem. Soc. 105, 4590 (1983)]. The σ and π covalency for CuBr2-4 are both higher than for CuCl2-4 in accord to the lower electronegativity for bromine. However, only for the antibonding 3b1g level of CuBr2-4 have we obtained an electronic charge lying mainly on ligands. The covalency of CdCl2:Cu2+ is smaller than that found for CuCl2-4, a fact associated to a higher metal-ligand distance for the former. Evidence of this statement are also given from the analysis of crystal-field spectra and isotropic shf constant. The values of K derived for CuCl2-4 (128.1×10-4 cm-1), CuBr2-4 (103.6×10-4 cm-1), and CdCl2:Cu2+ (123.9×10-4 cm-1) point out the dependence of K on the equatorial covalency but also on the existence of axial ligands. The [g] tensor of CuBr2-4 is dominated by the charge transfer contribution while the crystal field one is negative. Finally an analysis of the importance of each one of the involved contributions to the spin-Hamiltonian parameters is reported for the

  20. 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)

  1. Research progress in photolectric materials of CuFeS2

    Science.gov (United States)

    Jing, Mingxing; Li, Jing; Liu, Kegao

    2018-03-01

    CuFeS2 as a photoelectric material, there are many advantages, such as high optical absorption coefficient, direct gap semiconductor, thermal stability, no photo-recession effect and so on. Because of its low price, abundant reserves and non-toxic, CuFeS2 has attracted extensive attention of scientists.Preparation method of thin film solar cells are included that Electrodeposition, sputtering, thermal evaporation, thermal spraying method, co-reduction method.In this paper, the development of CuFeS2 thin films prepared by co-reduction method and co-reduction method is introduced.In this paper, the structure and development of solar cells, advantages of CuFeS2 as solar cell material, the structure and photoelectric properties and magnetic properties of CuFeS2, preparation process analysis of CuFeS2 thin film, research and development of CuFeS2 in solar cells is included herein. Finally, the development trend of CuFeS2 optoelectronic materials is analyzed and further research directions are proposed.

  2. Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K.; Al-Busaidi, M.; Gismelseed, A.; Al-Rawas, A. [Physics Department, College of Science, Sultan Qabos University, P. O. Box 36, Postal Code 123, Al-Khodh, Muscat (Oman)

    2004-05-01

    Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers (MLs) have been investigated. Although multilayered structure has been successfully obtained, a substantial interfacial roughness ranging from 0.6 nm to 1.2 nm has been determined. All Fe/Cu MLs were polycrystalline with an average grain size of about 10 nm. Fe was bcc and textured (110) whereas Cu was fcc(111). Transmission electron microscopy analysis showed that the fcc Cu layer was rather textured (110) and (100) at least in the first stage of growth of the Fe/Cu MLs. Conversion electron Moessbauer (CEMS) measurements indicated the existence of three phases. Two of them were magnetic with a dominant bcc Fe phase, followed by fcc Fe phase. The third phase was superparamagnetic. The CEMS results were explained in terms of the partial diffusion of Fe into Cu with three different zones. The small magnetoresistance (MR<0.2%) was correlated to Fe clusters located at Fe-Cu interfaces. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

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

    International Nuclear Information System (INIS)

    Parshin, P.P.; Zemlyanov, M.; 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 62 Cu 25.5 Fe 12.5 . 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.)

  4. 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.

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

    KAUST Repository

    Ma, Hongbin; Zhang, Junwei; Zhang, Hong; Lan, Qianqian; Guan, Chaoshuai; Zhang, Qiang; Bai, Feiming; Peng, Yong; Zhang, Xixiang

    2016-01-01

    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

  6. Adsorption performance of CuFe2O4/rGO nanocomposites towards organic dye

    International Nuclear Information System (INIS)

    Tang, Mingyi; Li, Xichuan; Gao, Chunjuan; Li, Xianxian; Qiu, Haixia

    2017-01-01

    A facile and efficient approach was employed to synthesize CuFe 2 O 4 /rGO (reduced graphene oxide) nanocomposites. The morphology, crystal structure and properties of the prepared CuFe 2 O 4 /rGO nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction and thermo-gravimetric analysis. The CuFe 2 O 4 /rGO nanocomposites were applied as adsorbents to study their adsorption performance for Congo red. The adsorption capacity and recyclability, adsorption dynamics and adsorption models were investigated. The results show that the CuFe 2 O 4 /rGO nanocomposites are efficient and recyclable adsorbents. - Highlights: • CuFe 2 O 4 /rGO was synthesized by a facile hydrothermal route. • As an adsorbent it showed high adsorption capacity to CR. • It was magnetically removable and has high reusability.

  7. Composition pathway in Fe-Cu-Ni alloy during coarsening

    Science.gov (United States)

    Mukherjee, Rajdip; Choudhury, Abhik; Nestler, Britta

    2013-10-01

    In this work the microstructure evolution for a two phase Fe-Cu-Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs-Thomson effect in a ternary alloy.

  8. Fe and Cu stable isotopes in archeological human bones and their relationship to sex.

    Science.gov (United States)

    Jaouen, Klervia; Balter, Vincent; Herrscher, Estelle; Lamboux, Aline; Telouk, Philippe; Albarède, Francis

    2012-07-01

    Accurate sex assignment of ancient human remains usually relies on the availability of coxal bones or well-preserved DNA. Iron (Fe) and copper (Cu) stable isotope compositions ((56)Fe/(54)Fe and (65)Cu/(63)Cu, respectively) were recently measured in modern human blood, and an unexpected result was the discovery of a (56)Fe-depletion and a (65)Cu-enrichment in men's blood compared to women's blood. Bones, being pervasively irrigated by blood, are expected to retain the (56)Fe/(54)Fe and (65)Cu/(63)Cu signature of blood, which in turn is useful for determining the sex of ancient bones. Here, we report the (56)Fe/(54)Fe, (65)Cu/(63)Cu, and (66)Zn/(64)Zn ratios from a suite of well-preserved phalanxes (n = 43) belonging to individuals buried in the 17th and 18th centuries at the necropolis of Saint-Laurent de Grenoble, France, and for which the sex was independently estimated from pelvic bone morphology. The metals were purified from the bone matrix by liquid chromatography on ion exchange resin and the isotope compositions were measured by multiple-collector inductively coupled plasma mass spectrometry. The results show that, as expected from literature data on blood, male bone iron is depleted in (56)Fe and enriched in (65)Cu relative to female. No sex difference is found in the (66)Zn/(64)Zn ratios of bone. The concentration and isotopic data show no evidence of soil contamination. Four samples of five (77%) can be assigned their correct sex, a result comparable to sex assignment using Fe and Cu isotopes in blood (81%). Isotopic analysis of metals may therefore represent a valid method of sex assignment applicable to incomplete human remains. Copyright © 2012 Wiley Periodicals, Inc.

  9. Orbital topology, interlayer spin coupling, and magnetic anisotropy of the CuFeO2 compound

    NARCIS (Netherlands)

    Malvestuto, M.; Bondino, F.; Magnano, E.; Lummen, T. T. A.; van Loosdrecht, P. H. M.; Parmigiani, F.

    2011-01-01

    X-ray absorption spectroscopy performed on a CuFeO2 single crystal reveals the pivotal role of the Cu ions in the discussion of the anisotropic properties of the compound. In particular, it is shown that there is a 3d hole density on the nominal 3d(10) Cu+ ions which may lie at the origin of the

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

    International Nuclear Information System (INIS)

    Caturla, M.J.; Soneda, N.; Alonso, E.; Wirth, B.D.; Diaz 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

  11. Sb interactions with TaC precipitates and Cu in ion-implanted α-Fe

    International Nuclear Information System (INIS)

    Follstaedt, D.M.; Myers, S.M.

    1980-01-01

    The interactions of Sb with the other species implanted into Fe to form Fe-Ta-C-Sb and Fe-Cu-Sb alloys have been examined with transmission electron microscopy and Rutherford backscattering following annealing at 873 0 K. Trapping of Sb at TaC precipitates is observed in the former alloy just as was previously observed in Fe-Ti-C-Sb. In Fe-Cu-Sb, Sb interactions are governed by the atomic ratio of Sb to Cu. For ratios between 0.2 to 0.4, the compound β-Cu 3 Sb was observed to form. For Sb to Cu ratios approx.< 0.1, fcc Cu precipitates were observed. In addition to the expected Sb dissolution in Cu, Sb trapping by Cu precipitates is also observed. The binding enthalpy of Sb at both TaC and Cu precipitates with respect to a solution site in the bcc Fe is the same as observed for TiC, approx. 0.4 eV. The constancy of the binding enthalpy at such chemically dissimilar precipitates supports the hypothesis that the trapping is due to the structural discontinuity of the precipitate-host interface. The observed Sb trapping at precipitates is of potential significance for the control of temper embrittlement in bcc steels

  12. Collinear Order in Frustrated Quantum Antiferromagnet on Square Lattice (CuBr)LaNb2O7

    Science.gov (United States)

    Oba, Noriaki; Kageyama, Hiroshi; Kitano, Taro; Yasuda, Jun; Baba, Yoichi; Nishi, Masakazu; Hirota, Kazuma; Narumi, Yasuo; Hagiwara, Masayuki; Kindo, Koichi; Saito, Takashi; Ajiro, Yoshitami; Yoshimura, Kazuyoshi

    2006-11-01

    Magnetic susceptibility, heat capacity, high-field magnetization and neutron diffraction measurements have been performed on a two-dimensional S = 1/2 square-lattice system (CuBr)LaNb2O7, prepared by a topotactic ion-exchange reaction of a nonmagnetic double-layered perovskite RbLaNb2O7. (CuBr)LaNb2O7 exhibits a second-order magnetic transition at 32 K, in marked contrast to a spin-singlet nature for its Cl-based counterpart (CuCl)LaNb2O7, despite nearly identical structural parameters. The magnetic structure is a novel collinear antiferromagnetic (CAF) ordering characterized by a modulation vector q = (π, 0, π) with a reduced moment of 0.6μB. Mixed ferromagnetic nearest-neighbor (J1) and antiferromagnetic second-nearest-neighbor (J2) interactions are of comparable strength (J1/kB = -35.6 K and J2/kB = 41.3 K), placing the system in a more frustrated region of the CAF phase than ever reported.

  13. Collinear order in frustrated quantum antiferromagnet on square lattice (CuBr)LaNb2O7

    International Nuclear Information System (INIS)

    Oba, Noriaki; Kageyama, Hiroshi; Kitano, Taro

    2006-01-01

    Magnetic susceptibility, heat capacity, high-field magnetization and neutron diffraction measurements have been performed on a two-dimensional s=1/2 square-lattice system (CuBr)LaNb 2 O 7 , prepared by a topotactic ion-exchange reaction of a nonmagnetic double-layered perovskite RbLaNb 2 O 7 . (CuBr)LaNb 2 O 7 exhibits a second-order magnetic transition at 32K, in marked contrast to a spin-singlet nature for its Cl-based counterpart (CuCl)LaNb 2 O 7 , despite nearly identical structural parameters. The magnetic structure is a novel collinear antiferromagnetic (CAF) ordering characterized by a modulation vector q=(π, 0, π) with a reduced moment of 0.6μ B . Mixed ferromagnetic nearest-neighbor (J 1 ) and antiferromagnetic second-nearest-neighbor (J 2 ) interactions are of comparable strength (J 1 /k B =-35.6K and J 2 /k B =41.3K), placing the system in a more frustrated region of the CAF phase than ever reported. (author)

  14. Preparation, characterization and photocatalytic activity of visible-light-driven plasmonic Ag/AgBr/ZnFe2O4 nanocomposites

    International Nuclear Information System (INIS)

    Li, Xiaojuan; Tang, Duanlian; Tang, Fan; Zhu, Yunyan; He, Changfa; Liu, Minghua; Lin, Chunxiang; Liu, Yifan

    2014-01-01

    Highlights: • A plasmonic Ag/AgBr/ZnFe 2 O 4 photocatalyst has been successfully synthesized. • Ag/AgBr/ZnFe 2 O 4 nanocomposites exhibit high visible light photocatalytic activity. • Ag/AgBr/ZnFe 2 O 4 photocatalyst is stable and magnetically separable. - Abstract: A visible-light-driven plasmonic Ag/AgBr/ZnFe 2 O 4 nanocomposite has been successfully synthesized via a deposition–precipitation and photoreduction through a novel one-pot process. X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy were employed to investigate the crystal structure, chemical composition, morphology, and optical properties of the as-prepared nanocomposites. The photocatalytic activities of the nanocomposites were evaluated by photodegradation of Rhodamine B (RhB) and phenol under visible light. The results demonstrated that the obtained Ag/AgBr/ZnFe 2 O 4 nanocomposites exhibited higher photocatalytic activity as compared to pure ZnFe 2 O 4 . In addition, the sample photoreduced for 20 min and calcined at 500 °C achieved the highest photocatalytic activity. Furthermore, the Ag/AgBr/ZnFe 2 O 4 nanocomposite has high stability under visible light irradiation and could be conveniently separated by using an external magnetic field

  15. Interlayer transport in the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br

    International Nuclear Information System (INIS)

    Zuo, F.; Su, X.; Alexandrakis, G.C.

    1997-01-01

    Interlayer magnetoresistance as a function of field and temperature with fields parallel and perpendicular to current direction in the organic superconductor κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br was measured. For H parallel I, the isothermal magnetoresistance R(H) displays a peak effect as a function of field. For H perpendicular I, R(H) increases monotonically with field. Comparison of the peak field with the H c2 (T) data suggests that the peak in R(H) occurs in the mixed state. We analyze the data in terms of the resistively shunted Josephson junction model and the density of states fluctuation model

  16. Experimental investigation of the effect of HBr additions on the lasing characteristics of a CuBr laser

    International Nuclear Information System (INIS)

    Shiyanov, D V; Sukhanov, V B; Andrienko, Oleg S; Evtushenko, Gennadii S

    2004-01-01

    It was experimentally determined that introducing small additions of HBr into the active elements of a CuBr laser is similar to the addition of hydrogen and significantly improves the output laser parameters. The effect of additions to small-volume active elements is most pronounced (up to a five-fold increase in output power) and is less pronounced in large-volume active elements (up to a twofold increase). A special-purpose HBr generator was elaborated, making it possible to promptly provide the requisite concentration of the active addition in a sealed-off active element. (lasers, active media)

  17. Neutron diffraction study of Fe-substituted YBa2Cu3O7

    International Nuclear Information System (INIS)

    Balagurov, A.M.; Mironova, G.M.; Pajaczkowska, A.; Piechota, J.; Shimchak, Kh.

    1989-01-01

    Neutron diffraction spectra of YBa 2 (Cu 1-x Fe x )O 7-δ (0 2 planes were determined. It is significant that the doped iron atoms occupy both of the copper site. The substitution of Fe for Cu in (2q) site is proportional to the concentration of iron in the sample. For small x there are a considerable amount of vacancies (10%) in the Cu1 site, which disappear quickly if x increases. Therefore, a joint effect of Cu substitution and the filling in vacancies by Fe occures for the Cu1 site. The amount of oxygen in samples increases with x up to 7.06 for x=0.12. Any visible effect of location of Fe at the Ba site is absent, but we can not exclude it completely. 20 refs.; 4 figs.; 1 tab

  18. Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

    Energy Technology Data Exchange (ETDEWEB)

    Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

    2016-12-15

    In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

  19. In-situ investigation of the icosahedral Al-Cu-Fe phase formation in thin films

    Energy Technology Data Exchange (ETDEWEB)

    Haidara, F., E-mail: fanta.haidara@im2np.fr [IM2NP, UMR 6242 CNRS - Universite Aix-Marseille, Av. Escadrille Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France); Duployer, B. [Universite Paul Sabatier CIRIMAT-LCMIE 2R1, 118, Route de Narbonne, 31062 Toulouse Cedex 09 (France); Mangelinck, D.; Record, M.-C. [IM2NP, UMR 6242 CNRS - Universite Aix-Marseille, Av. Escadrille Normandie-Niemen, Case 142, 13397 Marseille Cedex 20 (France)

    2012-09-05

    Highlights: Black-Right-Pointing-Pointer We investigated the phase formation of i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} in thin films. Black-Right-Pointing-Pointer We characterized the samples by DSC and in-situ XRD and resistance measurements. Black-Right-Pointing-Pointer The resistivity value for i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5} was determined. - Abstract: This work is an investigation of the formation by reactive diffusion at high temperatures of the icosahedral phase, i-Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}, in thin films. The samples were prepared by sputtering at room temperature. The elements Al, Cu and Fe were sequentially deposited onto oxidized silicon substrates. The two following stacking sequences, Al/Cu/Fe and Al/Fe/Cu, were investigated. The phase formation was studied using in situ resistivity, in situ X-ray Diffraction and Differential Scanning Calorimetry measurements. Whatever the stacking sequence, the sequences of phase formation evidenced during the heating treatment are similar. However the temperatures of formation for the first phases that are formed are different; they are higher in the case of the Al/Fe/Cu stacking sequence.

  20. Nitrate removal by Fe0/Pd/Cu nano-composite in groundwater.

    Science.gov (United States)

    Liu, Hongyuan; Guo, Min; Zhang, Yan

    2014-01-01

    Nitrate pollution in groundwater shows a great threat to the safety of drinking water. Chemical reduction by zero-valent iron is being considered as a promising technique for nitrate removal from contaminated groundwater. In this paper, Fe0/Pd/Cu nano-composites were prepared by the liquid-phase reduction method, and batch experiments of nitrate reduction by the prepared Fe0/Pd/Cu nano-composites under various operating conditions were carried out. It has been found that nano-Fe0/Pd/Cu composites processed dual functions: catalytic reduction and chemical reduction. The introduction of Pd and Cu not only improved nitrate removal rate, but also reduced the generation of ammonia. Nitrate removal rate was affected by the amount of Fe0/Pd/Cu, initial nitrate concentration, solution pH, dissolved oxygen (DO), reaction temperature, the presence of anions, and organic pollutant. Moreover, nitrate reduction by Fe0/Pd/Cu composites followed the pseudo-first-order reaction kinetics. The removal rate of nitrate and total nitrogen were about 85% and 40.8%, respectively, under the reaction condition of Fe-6.0%Pd-3.0%Cu amount of 0.25 g/L, pH value of 7.1, DO of 0.42 mg/L, and initial nitrate concentration of 100 mg/L. Compared with the previous studies with Fe0 alone or Fe-Cu, nano-Fe-6%Pd-3%Cu composites showed a better selectivity to N2.

  1. Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO_2 mediated heterogeneous activation of peroxymonosulfate

    International Nuclear Information System (INIS)

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

    2016-01-01

    Highlights: • CuFeO_2 microparticles were prepared by a microwave-assisted hydrothermal method. • CuFeO_2 microparticles efficiently catalyzed the activation of peroxymonosulfate. • Quenching experiments confirmed sulfate radicals as the major reactive radicals. • Carbamazepine was rapidly degraded by micro-CuFeO_2/peroxymonosulfate. • Feasibility of CuFeO_2/peroxymonosulfate was tested for treatment of actual water. - Abstract: Microscaled CuFeO_2 particles (micro-CuFeO_2) 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-CuFeO_2 was of pure phase and a rhombohedral structure with size in the range of 2.8 ± 0.6 μm. The micro-CuFeO_2 efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO_4·−), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO_2 was observed to be 6.9 and 25.3 times that of micro-Cu_2O and micro-Fe_2O_3, respectively. The enhanced activity of micro-CuFeO_2 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-CuFeO_2 can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu_2O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO_2 was effective in the studied actual aqueous environmental systems.

  2. Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO{sub 2} mediated heterogeneous activation of peroxymonosulfate

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yaobin, E-mail: yaobinding@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Hebin [College of Pharmacy, South-Central University for Nationalities, Wuhan 430074 (China); Zhang, Shenghua; Wang, Songbo [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China); Tang, Heqing, E-mail: tangheqing@mail.scuec.edu.cn [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074 (China)

    2016-11-05

    Highlights: • CuFeO{sub 2} microparticles were prepared by a microwave-assisted hydrothermal method. • CuFeO{sub 2} microparticles efficiently catalyzed the activation of peroxymonosulfate. • Quenching experiments confirmed sulfate radicals as the major reactive radicals. • Carbamazepine was rapidly degraded by micro-CuFeO{sub 2}/peroxymonosulfate. • Feasibility of CuFeO{sub 2}/peroxymonosulfate was tested for treatment of actual water. - Abstract: Microscaled CuFeO{sub 2} particles (micro-CuFeO{sub 2}) 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-CuFeO{sub 2} was of pure phase and a rhombohedral structure with size in the range of 2.8 ± 0.6 μm. The micro-CuFeO{sub 2} efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO{sub 4}·−), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO{sub 2} was observed to be 6.9 and 25.3 times that of micro-Cu{sub 2}O and micro-Fe{sub 2}O{sub 3}, respectively. The enhanced activity of micro-CuFeO{sub 2} 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-CuFeO{sub 2} can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu{sub 2}O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO{sub 2} was effective in the studied actual aqueous environmental systems.

  3. Quasicrystalline and crystalline phases in Al65Cu20(Fe, Cr)15 alloys

    International Nuclear Information System (INIS)

    Liu, W.; Koester, U.; Mueller, F.; Rosenberg, M.

    1992-01-01

    Two types of icosahedral quasicrystals are observed in Al 65 Cu 20 Fe 15-x Cr x (0 ≤ x ≤ 15) alloys, the face-centred AlCuFe-type icosahedral phase with dissoluted Cr and the primitive AlCuCr-type icosahedral phase with dissoluted Fe. In the vicinity of Al 65 Cu 20 Fe 8 Cr 7 a stable decagonal phase (a=0.45 nm and c=1.23 nm) forms competitively with the icosahedral quasicrystals. All these three quasicrystalline phases can be regarded as Hume-Rothery phases stabilized by the energy band factor. The density is measured to be 4.57, 4.44, and 4.11 g/cm 3 for the icosahedral Al 65 Cu 20 Fe 15 , the decagonal Al 65 Cu 20 Fe 8 Cr 7 , and the icosahedral Al 65 Cu 20 Cr 15 alloys, respectively. Depending on the composition in the range between Al 65 Cu 20 Fe 8 Cr 7 and Al 65 Cu 20 Cr 15 , several crystalline phases are observed during the transormation of the AlCuCr-type icosahedral phase: the 1/1-3/2-type orthorhombic (o) and the 1/0-3/2-type tetragonal (t) approximants of the decagonal phase, a hexagonal (h) phase, as well as a long-range vacancy ordered τ 3 -phase derived from a CsCl-type structure with a=0.2923 nm. The structures of all the crystalline phases are closely related to those of the icosahedral (i) and decagonal (d) quasicrystals, which leads to a definite orientation relationship as follows: i5 parallel d10 parallel o[100] parallel t[100] parallel h[001] parallel τ 3 [110]. (orig.)

  4. X-ray diffraction study of chalcopyrite CuFeS2, pentlandite (Fe,Ni)9S8 and Pyrrhotite Fe1-xS obtained from Cu-Ni orebodies

    International Nuclear Information System (INIS)

    Nkoma, J.S.; Ekosse, G.

    1998-05-01

    The X-ray Diffraction (XRD) technique is applied to study five samples of Cu-Ni orebodies, and it is shown that they contain chalcopyrite CuFeS 2 as the source of Cu, pentlandite (Fe,Ni) 9 S 8 as the source of Ni and pyrrhotite Fe 1-x S as a dominant compound. There are also other less dominant compounds such as bunsenite NiO, chalcocite Cu 2 S, penrosite (Ni, Cu)Se 2 and magnetite Fe 3 O 4 . Using the obtained XRD data, we obtain the lattice parameters for tetragonal chalcopyrite as a=b=5.3069A and c=10.3836A, cubic pentlandite as a=b=c=10.0487A, and hexagonal pyrrhotite as a=b=6.8820A and c=22.8037A. (author)

  5. Characterization of transparent superconductivity Fe-doped CuCrO{sub 2} delafossite oxide

    Energy Technology Data Exchange (ETDEWEB)

    Taddee, Chutirat [Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Kamwanna, Teerasak, E-mail: teekam@kku.ac.th [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand); Amornkitbamrung, Vittaya [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand)

    2016-09-01

    Graphical abstract: - Highlights: • Effect of Fe substitution on the physical properties in CuCrO{sub 2} is studied. • The substitution of Cr{sup 3+} by Fe{sup 3+} produces a mixed effect on the magnetic properties. • CuCr{sub 1−x}Fe{sub x}O{sub 2} delafossite oxides show transparent superconductivity. - Abstract: Delafossite CuCr{sub 1−x}Fe{sub x}O{sub 2} (0.0 ≤ x ≤ 0.15) semiconductors were synthesized using a self-combustion urea nitrate process. The effects of Fe concentration on its microstructural, optical, magnetic, and electrical properties were investigated. X-ray diffraction (XRD) analysis results revealed the delafossite structure in all the samples. The lattice spacing of CuCr{sub 1−x}Fe{sub x}O{sub 2} slightly increased with increasing substitution of Fe at the Cr sites. The optical properties measured at room temperature using UV–visible spectroscopy showed a weak absorbability in the visible light and near IR regions. The corresponding direct optical band gap was about 3.61 eV, exhibiting transparency in the visible region. The magnetic hysteresis loop measurements showed that the Fe-doped CuCrO{sub 2} samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe{sup 3+} for Cr{sup 3+} produced a mixed effect on the magnetic properties of CuCrO{sub 2} delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr{sub 1−x}Fe{sub x}O{sub 2} with a superconducting transition up to 118 K.

  6. Nucleation and growth of a BCC Fe phase deposited on a single crystal (001) Cu film

    International Nuclear Information System (INIS)

    Koike, J.

    1991-01-01

    As a thin film overlayer grows on a substrate with a different structure, the overlayer initially adopts the substrate structure and subsequently transforms to an equilibrium bulk structure. such a growth characteristic has been extensively studied in Fe/Cu bicrystals. An Fe overlayer grown on a Cu substrate is known to have the fcc structure up to a thickness of 2 nm, whereas a thicker Fe overlayer consists of submicrometer grains of the bcc-Cu has been reported in a relatively thick Fe film and was found to consist of the Nishiyama (N), Kurdjumov-Sacks (KS), or Pitsch (P), depending on the orientation of the substrate surface. However, previous studies have not explained how the bcc structure nucleates or how the observed submicrometer polycrystalline grains form. The paper provides an understanding of these two points. Transmission electron microscopy (TEM) was used to study Fe/Cu bicrystals as the Fe thickness was varied systematically. Analysis of moire fringes, which are caused by superposition of different structures, enabled us to determine the orientation relationship between the very thin Fe layer and the Cu substrate. We show that a single variant of the P orientation relationship, which accompanies atomic rearrangement parallel to the interface, predominates at the nucleation stage of the bcc structure. Nucleation of other variants of P, N, and KS occurs with increasing Fe thickness and causes the formation of the submicrometer bcc grains

  7. Synthesis of FeSiBPNbCu nanocrystalline soft-magnetic alloys with high saturation magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zongzhen [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Wang, Anding; Chang, Chuntao [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, 519 Zhuangshi Road, Zhenhai District, Ningbo, Zhejiang 315201 (China); Wang, Yanguo [Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing 100080 (China); Dong, Bangshao [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Zhou, Shaoxiong, E-mail: sxzhou@atmcn.com [China Iron and Steel Research Institute Group, Advanced Technology and Materials Co., Ltd., Beijing 100081 (China)

    2014-10-25

    Highlights: • Thermal stability of the FeSiBPNbCu alloys is strongly dependent on the Fe content. • The FeSiBPNbCu alloys with high Fe content exhibit good soft magnetic properties. • The coexistence of Cu, P and Nb leads to the excellent soft magnetic properties. - Abstract: A series of [Fe{sub 0.76+x}(Si{sub 0.4}B{sub 0.4}P{sub 0.2}){sub 0.24−x}]{sub 98.25}Nb{sub 1}Cu{sub 0.75} (x = 0–0.08) nanocrystalline soft-magnetic alloys with high saturation magnetization were synthesized by adjusting Fe content and improving the crystallization behavior, soft-magnetic properties and microstructure. It is found that the temperature interval between the two crystallization peaks is significantly enlarged from 50 to 180 °C when the Fe content of the alloys increases from x = 0 to x = 0.08, which greatly expands the optimum annealing temperature range. The alloys with higher Fe content are prone to form more uniform nanocomposite microstructure with better thermal stability and soft magnetic properties. The Fe-rich FeSiBPNbCu nanocrystalline alloys with x = 0.08 exhibit excellent soft-magnetic properties, including the high saturation magnetic flux density of up to 1.74 T, low coercivity of about 3.3 A/m and high effective permeability of more than 2.2 × 10{sup 4} at 1 kHz under a field of 1 A/m. The combination of excellent soft-magnetic properties, low cost and good productivity makes the FeSiBPNbCu alloys to be a kind of promising soft-magnetic materials for electrical and electronic industry applications.

  8. Moessbauer studies of 57Fe substitution of Cu ions in superconducting oxides

    International Nuclear Information System (INIS)

    Saitovitch, E.B.

    1988-01-01

    Since the discovery of high-T c superconductivity in YBa 2 Cu 3 O 7 oxides several studies of metal ions substitutions were reported. The observed depression on T c without a systematic correlation with the charge and magnetic moment of Cu substituents claims for more detailed information about its local properties as can be revealed by 57 Fe Moessbauer spectroscopy. The results for different iron concentrations combined with modifications of the superconducting transition are discussed concerning the presence of magnetic moments on the Fe ions and the preferential occupation of Cu(1) sites, recently confirmed by neutron and electron diffraction experiments. The oxygen coordination for the different iron species are proposed on the basis of their dependence on Fe concentration, their behavior at high temperatures as well as the electron diffraction and electron microscopy measurements reported for Fe: YBa 2 Cu 3 O 7 samples. (author) [pt

  9. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability

    Directory of Open Access Journals (Sweden)

    Andrea Školáková

    2017-11-01

    Full Text Available In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  10. Magnetic Excitations in Cu2Fe2Ge4O13

    International Nuclear Information System (INIS)

    Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.

    2005-01-01

    Magnetic excitations in the cooperative ordered state in a weakly coupled Fe chains and Cu dimers compound Cu 2 Fe 2 Ge 4 O 13 is studied by thermal neutron scattering technique. We show that the low energy excitations up to 10 meV in wide q range are well described by spin wave theory of weakly coupled Fe chains. In higher energy range a narrow band excitation that can be associated with Cu dimers is observed at ℎω-24 meV. Both types of excitations can be understood by treating the weak coupling between Fe chains and Cu dimers at the level of Mean Field/Random Phase Approximation.

  11. Hydroxylation of benzene to phenol over magnetic recyclable nanostructured CuFe mixed-oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2015-03-01

    Full Text Available A highly active and magnetically recyclable nanostructured copper–iron oxide (CuFe) catalyst has been synthesized for hydroxylation of benzene to phenol under mild reaction conditions. The obtained catalytic results were correlated with the catalyst...

  12. Crystal structure and magnetism of layered perovskites compound EuBaCuFeO5

    Science.gov (United States)

    Lal, Surender; Mukherjee, K.; Yadav, C. S.

    2018-04-01

    Layered perovskite compounds have interesting multiferroic properties.YBaCuFeO5 is one of the layered perovskite compounds which have magnetic and dielectric transition above 200 K. The multiferroic properties can be tuned with the replacement of Y with some other rare earth ions. In this manuscript, structural and magnetic properties of layered perovskite compound EuBaCuFeO5 have been investigated. This compound crystallizes in the tetragonal structure with P4mm space group and is iso-structural with YBaCuFeO5. The magnetic transition has been found to shift to 120 K as compared to YBaCuFeO5 which has the transition at 200 K. This shift in the magnetic transition has been ascribed to the decrease in the chemical pressure that relaxes the magnetic moments.

  13. Structure and Mechanical Properties of Al-Cu-Fe-X Alloys with Excellent Thermal Stability.

    Science.gov (United States)

    Školáková, Andrea; Novák, Pavel; Mejzlíková, Lucie; Průša, Filip; Salvetr, Pavel; Vojtěch, Dalibor

    2017-11-05

    In this work, the structure and mechanical properties of innovative Al-Cu-Fe based alloys were studied. We focused on preparation and characterization of rapidly solidified and hot extruded Al-Cu-Fe, Al-Cu-Fe-Ni and Al-Cu-Fe-Cr alloys. The content of transition metals affects mechanical properties and structure. For this reason, microstructure, phase composition, hardness and thermal stability have been investigated in this study. The results showed exceptional thermal stability of these alloys and very good values of mechanical properties. Alloying by chromium ensured the highest thermal stability, while nickel addition refined the structure of the consolidated alloy. High thermal stability of all tested alloys was described in context with the transformation of the quasicrystalline phases to other types of intermetallics.

  14. Reduction of crystallization temperature of the Nd-Fe-B thin films by Cu addition

    International Nuclear Information System (INIS)

    Ma Yungui; Yang Zheng; Matsumoto, M.; Morisako, A.; Takei, S.

    2004-01-01

    Nonmagnetic Cu element has been doped into the sputtered Nd-Fe-B thin films. It is found that the introduction of suitable amount of copper atoms could reduce the crystallization temperature of the 2:14:1 phase by near 100 deg. C, compared with that without Cu. For the 15 nm Nd 16 Fe 70.2 Cu 1.8 B 12 film deposited at 340 deg. C, perpendicular coercivity and remanent magnetization ratio of 350 kA/m and 0.96 have been successfully obtained. Cu addition would lead to the grain growth, but the average grain size in the films could be greatly decreased through lowering the deposition temperature. These results are compared with those found in the fabrication of FePtCu films

  15. Enhanced photocatalytic performances and magnetic recovery capacity of visible-light-driven Z-scheme ZnFe2O4/AgBr/Ag photocatalyst

    Science.gov (United States)

    He, Jie; Cheng, Yahui; Wang, Tianzhao; Feng, Deqiang; Zheng, Lingcheng; Shao, Dawei; Wang, Weichao; Wang, Weihua; Lu, Feng; Dong, Hong; Zheng, Rongkun; Liu, Hui

    2018-05-01

    High efficiency, high stability and easy recovery are three key factors for practical photocatalysts. Z-scheme heterostructure is one of the most promising photocatalytic systems to meet all above requirements. However, efficient Z-scheme photocatalysts which could absorb visible light are still few and difficult to implement at present. In this work, the composite photocatalysts ZnFe2O4/AgBr/Ag were prepared through a two-step method. A ∼92% photodegradation rate on methyl orange was observed within 30 min under visible light, which is much better than that of individual ZnFe2O4 or AgBr/Ag. The stability was also greatly improved compared with AgBr/Ag. The increased performance is resulted from the suitable band alignment of ZnFe2O4 and AgBr, and it is defined as Z-scheme mechanism which was demonstrated by detecting active species and electrochemical impedance spectroscopy. Besides, ZnFe2O4/AgBr/Ag is ferromagnetic and can be recycled by magnet. These results show that ZnFe2O4/AgBr/Ag is a potential magnetically recyclable photocatalyst which can be driven by visible light.

  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. A Question of Balance: Facing the challenges of Cu, Fe and Zn Homeostasis

    OpenAIRE

    Palmer, Christine; Guerinot, Mary Lou

    2009-01-01

    Plants have recently moved into the spotlight with the growing realization that the world needs solutions to energy and food production that are sustainable and environmentally sound. Iron (Fe), copper (Cu), and zinc (Zn) are essential for plant growth and development, yet the same properties that make these transition metals indispensable can also make them deadly in excess. Fe and Cu are most often utilized for their redox properties, while Zn is primarily utilized for is ability to act as ...

  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. Structural evolutions of the mechanically alloyed Al70Cu20Fe10 ...

    Indian Academy of Sciences (India)

    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 ...

  20. Facile preparation of magnetic mesoporous Fe_3O_4/C/Cu composites as high performance Fenton-like catalysts

    International Nuclear Information System (INIS)

    Li, Keyan; Zhao, Yongqin; Janik, Michael J.; Song, Chunshan; Guo, Xinwen

    2017-01-01

    Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe_3O_4/C/Cu was obtained by calcining tartrate under N_2. • Fe_3O_4/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe_2O_3/CuO and α-Fe_2O_3/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe_3O_4/C/Cu was obtained by calcining the tartrate precursor under N_2 atmosphere at 500 °C. The Fe_3O_4/C/Cu composite possessed mesoporous structure and large surface area up to 133 m"2 g"−"1. The Fenton catalytic performance of Fe_3O_4/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe"3"+ to Fe"2"+, which accelerated the Fe"3"+/Fe"2"+ cycles and favored H_2O_2 decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe"3"+ and Cu"2"+, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe_3O_4/C/Cu-H_2O_2 system, and MB (100 mg L"−"1) was nearly removed within 60 min. The Fe_3O_4/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile, cheap and green method for the synthesis of mesoporous composites as excellent Fenton-like catalysts, without any additional reductants or organic

  1. Detailed single crystal EPR lineshape measurements for the single molecule magnets Fe8Br and Mn12-ac

    OpenAIRE

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

    2001-01-01

    It is shown that our multi-high-frequency (40-200 GHz) resonant cavity technique yields distortion-free high field EPR spectra for single crystal samples of the uniaxial and biaxial spin S = 10 single molecule magnets (SMMs) [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O and [Fe8O2(OH)12(tacn)6]Br8.9H2O. The observed lineshapes exhibit a pronounced dependence on temperature, magnetic field, and the spin quantum numbers (Ms values) associated with the levels involved in the transitions. Measurements ...

  2. CuFeO2 formation using fused deposition modeling 3D printing and sintering technique

    Science.gov (United States)

    Salea, A.; Dasaesamoh, A.; Prathumwan, R.; Kongkaew, T.; Subannajui, K.

    2017-09-01

    CuFeO2 is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO2 such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO2 is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO2. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO2 are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kolesnikov, S. V., E-mail: kolesnikov@physics.msu.ru; Klavsyuk, A. L.; Saletsky, A. M. [Moscow State University, Faculty of Physics (Russian Federation)

    2015-10-15

    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.

  4. Leaching of rapidly quenched Al65Cu20Fe15 quasicrystalline ribbons

    Indian Academy of Sciences (India)

    2017-12-06

    Dec 6, 2017 ... stood that Al–Cu–Fe QC also presents an FCI structure similar to that .... that the precipitation rate of Fe is lower than that of Cu. Figure 2a shows the .... Renewable Energy (MNRE), India, under Mission Mode. Hydrogen ...

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

    International Nuclear Information System (INIS)

    Guo, Yanwei; Zhu, Zhiliang; Qiu, Yanling; Zhao, Jianfu

    2012-01-01

    Highlights: ► A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized. ► The average pore size of the materials with about 16 nm indicated that the mesoporous structures existed in the Cu/Mg/Fe/La-LDHs. ► The adsorption capacity of As(V) increased with the increment of La 3+ content in the LDH. ► 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 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 3+ and La 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 4 2− , CO 3 2− , SO 4 2− , Cl − and NO 3 − 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.

  6. Vortex pinning in layered organic superconductors: κ-(BEDT-TTF)2Cu[N(CN)2]Br

    International Nuclear Information System (INIS)

    Khizroev, S.; Zuo, F.; Alexandrakis, G.C.; Schlueter, J.A.; Geiser, U.; Williams, J.M.

    1996-01-01

    Magnetization studies on organic single-crystal superconductors of κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br with the field H parallel to the b axis (perpendicular to the conducting plane) show anomalous field and temperature dependence of vortex pinning in the mixed state. At high temperatures, the magnetization M decays with increasing field with a power-law dependence. The normalized relaxation rate S=d(lnM)/d(lnt) decreases monotonically with H. At low temperatures (T rev shows a universal power-law dependence of H rev on (1-T/T c ) in the temperature range investigated. We suggest that the magnetic anomaly observed is due to a dimensional crossover in the nature of vortex pinning. copyright 1996 American Institute of Physics

  7. Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2017-12-01

    Full Text Available (FePt85Cu15 nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium. Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature. Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature. It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

  8. 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.)

  9. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  10. Magnetic and structural properties of Cu0.85Fe0.15O system synthesized by co-precipitation

    International Nuclear Information System (INIS)

    Colorado, H. D.; Pérez Alcázar, G. A.

    2011-01-01

    Cu 0.94 Fe 0.06 O and Cu 0.85 Fe 0.15 O samples were synthesized by using the co-precipitation chemical method. Starting from aqueous solutions of copper nitrate, CuO (NO 3 ) 2 3H 2 O, iron nitrate, Fe (NO 3 ) 3 9H 2 O and sodium hydroxide as precipitating agent, NaOH. The precipitate of three samples for Cu 0.94 Fe 0.06 O and five for Cu 0.85 Fe 0.15 O of fine powder were calcined for 5 h at different temperatures. The obtained X rays diffraction patterns refined by the Rietveld method show the CuO characteristic pattern, showing that the Fe atoms enter to replace Cu atoms. Furthermore, it was obtained that the crystallite size decreases with calcination temperatures for Cu 0.94 Fe 0.06 O. The transmission Mössbauer spectroscopy showed that the samples present a disordered paramagnetic behavior due to the big value of the half-width of line of the quadrupolar splitting. Vibrating sample magnetometry confirms the paramagnetic character. The XRD results indicate that the material is nanostructured, due that the crystallite sizes are of the order of 10 nm for Cu 0.94 Fe 0.06 O and 40 nm for Cu 0.85 Fe 0.15 O.

  11. Dielectric Study of the Phase Transitions in [P(CH3)4]2CuY4 (Y = Cl, Br)

    Science.gov (United States)

    Gesi, Kazuo

    2002-05-01

    Phase transitions in [P(CH3)4]2CuY4 (Y = Cl, Br) have been studied by dielectric measurements. In [P(CH3)4]2CuCl4, a slight break and a discontinuous jump on the dielectric constant vs. temperature curve are seen at the normal-incommensurate and the incommensurate-commensurate phase transitions, respectively. A small peak of dielectric constant along the b-direction exists just above the incommensurate-to-commensurate transition temperature. The anisotropic dielectric anomalies of [P(CH3)4]2CuBr4 at phase transitions were measured along the three crystallographic axes. The pressure-temperature phase diagram of [P(CH3)4]2CuCl4 was determined. The initial pressure coefficients of the normal-to-incommensurate and the incommensurate-to-commensurate transition temperatures are 0.19 K/MPa and 0.27 K/MPa, respectively. The incommensurate phase in [P(CH3)4]2CuCl4 disappears at a triple point which exists at 335 MPa and 443 K. The stability and the pressure effects of the incommensurate phases are much different among the four [Z(CH3)4]2CuY4 crystals (Z = N, P; Y = Cl, Br).

  12. Sequestration of chelated copper by structural Fe(II): Reductive decomplexation and transformation of Cu{sup II}-EDTA

    Energy Technology Data Exchange (ETDEWEB)

    He, Hongping [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Wu, Deli, E-mail: wudeli@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Zhao, Linghui [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China); Luo, Cong [School of Civil and Environmental Engineering, Georgia Institute of Technology, GA 30332 (United States); Dai, Chaomeng; Zhang, Yalei [State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science & Engineering, Tongji University, Shanghai 200092 (China)

    2016-05-15

    Highlights: • Structural Fe(II) was found to reveal high sequestration potential in various chelated copper. • Chelated copper was reduced to Cu(0) and Cu{sub 2}O by =Fe(II), whcih was oxidized to Fe{sub 2}O{sub 3}·H{sub 2}O. • Both electron transfer and surface =Fe(II) were found to be crucial during chelated copper reduction. • The indispensible role of reductive decomplexation was identified in chelated copper sequestration. - Abstract: Chelated coppers, such as Cu{sup II}-EDTA, are characteristically refractory and difficult to break down because of their high stability and solubility. Cu{sup II}–EDTA sequestration by structural Fe(II) (=Fe(II)) was investigated intensively in this study. Up to 101.21 mgCu(II)/gFe(II) was obtained by =Fe(II) in chelated copper sequestration under near neutral pH condition (pH 7.70). The mechanism of Cu{sup II}-EDTA sequestration by =Fe(II) was concluded as follows: 3Cu{sup II}–EDTA + 7=Fe(II) + 9H{sub 2}O → Cu(0) ↓ + Cu{sub 2}O ↓ (the major product) + 2Fe{sub 2}O{sub 3}·H{sub 2}O ↓ + 3Fe{sup II}–EDTA +14H{sup +} Novel results strongly indicate that Cu{sup II} reductive transformation induced by surface =Fe(II) was mainly responsible for chelated copper sequestration. Cu(0) generation was initially facilitated, and subsequent reduction of Cu(II) into Cu(I) was closely combined with the gradual increase of ORP (Oxidation-Reduction Potential). Cu-containing products were inherently stable, but Cu{sub 2}O would be reoxidized to Cu(II) with extra-aeration, resulting in the release of copper, which was beneficial to Cu reclamation. Concentration diminution of Cu{sup II}–EDTA within the electric double layer and competitive adsorption were responsible for the negative effects of Ca{sup 2+}, Mg{sup 2+}. By generating vivianite, PO{sub 4}{sup 3−} was found to decrease surface =Fe(II) content. This study is among the first ones to identify the indispensible role of reductive decomplexation in chelated copper

  13. Granulation of Cu-Al-Fe-Ni Bronze

    Directory of Open Access Journals (Sweden)

    Pisarek B.P.

    2014-08-01

    Full Text Available With the increase in wall thickness of the casting of iron-nickel-aluminium-bronze, by the reduction of the cooling rate the size of κII phase precipitates increases. This process, in the case of complex aluminium bronzes with additions of Cr, Mo and W is increased. Crystallization of big κII phase, during slow cooling of the casting, reduces the concentration of additives introduced to the bronze matrix and hardness. Undertaken research to develop technology of thick-walled products (g> 6 mm of complex aluminium bronzes. Particular attention was paid to the metallurgy of granules. As a result, a large cooling speed of the alloy, and also high-speed solidification casting a light weight of the granules allows: to avoid micro-and macrosegregation, decreasing the particle size, increase the dispersion of phases in multiphase alloys. Depending on the size granules as possible is to provide finished products with a wall thickness greater than 6 mm by infiltration of liquid alloy of granules (composites. Preliminary studies was conducted using drip method granulate of CuAl10Fe5Ni5 bronze melted in a INDUTHERM-VC 500 D Vacuum Pressure Casting Machine. This bronze is a starting alloy for the preparation of the complex aluminium bronzes with additions of Cr, Mo, W and C or Si. Optimizations of granulation process was carried out. As the process control parameters taken a casting temperature t (°C and the path h (mm of free-fall of the metal droplets in the surrounding atmosphere before it is intensively cooled in a container of water. The granulate was subjected to a sieve analysis. For the objective function was assume maximize of the product of Um*n, the percentage weight “Um” and the quantity of granules ‘n’ in the mesh fraction. The maximum value of the ratio obtained for mesh fraction a sieve with a mesh aperture of 6.3 mm. In the intensively cooled granule of bronze was identified microstructure composed of phases: β and fine bainite

  14. Moessbauer study of (Fe1-x Cu x )4N (0.05≤x≤0.15) films

    International Nuclear Information System (INIS)

    El Khiraoui, S.; Sajieddine, M.; Vergnat, M.; Bauer, Ph.; Mabrouki, M.

    2007-01-01

    In this work, we have prepared nitrogenated Fe 1- x Cu x alloys by reactive evaporation under a flow of nitrogen ions. After annealing, X-ray diffraction shows that we have synthesized the γ'-(Fe 1- x Cu x ) 4 N (0.05≤x≤0.15) compounds. The films were investigated by Moessbauer spectroscopy. The crystallographic structure and the respective positions of the Fe and Cu atoms in the compounds have been determined

  15. MAGNETIC AND HYPERFINE CHARACTERIZATION OF THE THERMAL TRANSFORMATION CuO - Fe2O3 TO Fe3O4

    Directory of Open Access Journals (Sweden)

    Juan D. Betancur

    2018-01-01

    Full Text Available A magnetic study about the thermal transformation of hematite doped with CuO (Fe2O3 + CuO is presented. The heat treatment was carried out at a temperature of 375 ± 1 ºC, in a controlled atmosphere composed by 20% hydrogen and 80% nitrogen. Samples were characterized by Mössbauer spectroscopy at room temperature, magnetization as a function of temperature and hysteresis loops at 10K. Our results suggest that both the hyperfine fields and linewidths of the A and B sites remain essentially constant with increasing the CuO concentration, while at the same time a paramagnetic component arises, which is indicative of the appearance of a precipitate or a new phase of Fe-Cu, i.e. there is not an effective incorporation of the copper into the structure of the magnetite. The saturation magnetization falls from approximately 87 emu/g to 78 emu/g, consistent with such a paramagnetic phase. Also, an increase in the coercivity from ~576 Oe up to ~621 Oe by increasing the percentage of CuO from 2% up to 20% is observed. Such increase is also attributed to the paramagnetic phase acting as pinning center for domain walls, besides also de pinning effect due to vacancies induced by the thermal treatment. Finally, an inversion of the magnetization in the Verwey temperature is observed. The data suggest that by means of the synthesis method employed, it is possible to obtain Fe3O4 magnetite particles coexisting with precipitates of Fe-Cu, giving rise to a modification in the magnetic properties and generatingan interesting effect in the magnetization at the Verwey temperature.

  16. Room temperature ferromagnetism in Fe-doped CuO nanoparticles.

    Science.gov (United States)

    Layek, Samar; Verma, H C

    2013-03-01

    The pure and Fe-doped CuO nanoparticles of the series Cu(1-x)Fe(x)O (x = 0.00, 0.02, 0.04, 0.06 and 0.08) were successfully prepared by a simple low temperature sol-gel method using metal nitrates and citric acid. Rietveld refinement of the X-ray diffraction data showed that all the samples were single phase crystallized in monoclinic structure of space group C2/c with average crystallite size of about 25 nm and unit cell volume decreases with increasing iron doping concentration. TEM micrograph showed nearly spherical shaped agglomerated particles of 4% Fe-doped CuO with average diameter 26 nm. Pure CuO showed weak ferromagnetic behavior at room temperature with coercive field of 67 Oe. The ferromagnetic properties were greatly enhanced with Fe-doping in the CuO matrix. All the doped samples showed ferromagnetism at room temperature with a noticeable coercive field. Saturation magnetization increases with increasing Fe-doping, becomes highest for 4% doping then decreases for further doping which confirms that the ferromagnetism in these nanoparticles are intrinsic and are not resulting from any impurity phases. The ZFC and FC branches of the temperature dependent magnetization (measured in the range of 10-350 K by SQUID magnetometer) look like typical ferromagnetic nanoparticles and indicates that the ferromagnetic Curie temperature is above 350 K.

  17. 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 %.

  18. Effect of foliar applied (Zn, Fe, Cu and Mn) in citrus production

    International Nuclear Information System (INIS)

    Khurshid, F.; Sarwar, S.; Khattak, R.A.

    2008-01-01

    A study was conducted to evaluate the impact of micronutrients (Zn, Fe, Cu and Mn) on sweet orange (Citrus Sinensis L.), blood red var., on farmer's orchard at Khanpur, district Haripur, NWFP, during 2002-03. Micronutrients were applied in foliar sprays over the canopy of each tree. The main effects and interactions of Zinc sulphate (Zn), iron sulphate (Fe), Copper Sulphate (Cu) and Manganese Sulphate (Mn) were studied in factorial combinations. A basal dose of nitrogen, phosphorus and potassium was applied at the rate 1.5, 1 and 1 kg tree/sup -1/. Zn, Fe, Cu and Mn were applied alone and in various combinations at the rate 0.115, 0.057, 0.05 and 0.13 kg in 100 liters of water. Application of micronutrients significantly increased Zn, Fe, Cu and Mn concentrations in leaves, compared with control. Zn treatments significantly increased the yield, number of fruit and total sugar. Manganese treatments significantly increased the total soluble solids and reduced the acidity of fruit juice. Other quality parameters, including fruit size, percent peel, percent pulp, sugar as well as total soluble solids, were improved with the application of Zn, Fe, Cu and Mn. (author)

  19. Simple electrodepositing of CoFe/Cu multilayers: Effect of ferromagnetic layer thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Tekgül, Atakan, E-mail: atakantekgul@gmail.com [Akdeniz University, Physics Department, Science Faculty, TR-07058 Antalya (Turkey); Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Alper, Mürsel [Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Kockar, Hakan [Balikesir University, Physics Department, Science and Literature Faculty, TR-10145 Balikesir (Turkey)

    2017-01-01

    The CoFe/Cu magnetic multilayers were produced by changing CoFe ferromagnetic layers from 3 nm to 10 nm using electrodeposition. By now, the thinnest Cu (0.5 nm) layer thicknesses were used to see whether the GMR effect in the multilayers can be obtained or not since the pinning of non-magnetic layer between the ferromagnetic layers is required. For the proper depositions, the cyclic voltammograms was used, and the current–time transients were obtained. The Cu and CoFe layers were deposited at a cathode potential of −0.3 and −1.5 V with respect to saturated calomel electrode, respectively. From the XRD patterns, the multilayers were shown to be fcc crystal structures. For the magnetization measurements, saturation magnetization increases from 160 to 600 kA/m from 3 to 8 nm ferromagnetic layer thicknesses. And, the coercivity values increase until the 8 nm of the CoFe layer thickness. It is seen that the thin Cu layer (fixed at 0.5 nm) and pinholes support the random magnetization orientation and thus all multilayers exhibited the giant magnetoresistance (GMR) effect, and the highest GMR value was observed about 5.5%. And, the variation of GMR field sensitivity was calculated. The results show that the GMR and GMR sensitivity are compatible among the multilayers. The CoFe/Cu magnetic multilayers having GMR properties are used in GMR sensors and hard disk drive of the nano-technological devices. - Highlights: • The much thinner (0.5 nm) Cu layer was used to obtain the GMR effect on the electrodeposited CoFe/Cu multilayers. • All samples exhibited GMR and the maximum GMR value was 5.5%. • The M{sub s} and the H{sub c} changed with increasing magnetic layer thickness.

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

    International Nuclear Information System (INIS)

    Al-Ebraheem, A.; Mersov, A.; Gurusamy, K.; Farquharson, M.J.

    2010-01-01

    A microbeam synchrotron X-ray fluorescence (μSRXRF) 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 μm 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.

  1. Fe and Cu in Si: Lattice sites and trapping at implantation-related defects

    International Nuclear Information System (INIS)

    Wahl, U.; Correia, J.G.; Rita, E.; Araujo, J.P.; Soares, J.C.

    2006-01-01

    We have used the emission channeling technique in order to study the lattice sites of radioactive 59 Fe and 67 Cu following 60 keV ion implantation into Si single crystals at fluences around 10 12 -10 14 cm -2 . We find that in the room temperature as-implanted state in high-resistivity Si both Fe and Cu occupy mainly lattice sites displaced around 0.05 nm (0.5 A) from substitutional positions. Both are released from these positions during annealing at temperatures between 300 deg. C and 600 deg. C. Fe is then found mainly on near-tetrahedral interstitial sites and further annealing causes it to be increasingly incorporated on ideal substitutional sites, on which it is stable to around 800 deg. C. We have strong indications that during annealing around 600 deg. C, along with the dominance of interstitial Fe, a redistribution towards the surface takes place, suggesting that the subsequent formation of ideal substitutional Fe may be related to the trapping of Fe at R p /2, half of its implanted depth. Possible R p /2 trapping might also have taken place in our Cu experiments but appears to be less efficient since Cu tended to escape to the bulk of the samples

  2. Crystal and magnetic structures of CaCu3Fe4O12 and LaCu3Fe4O12: distinct charge transitions of unusual high valence Fe

    International Nuclear Information System (INIS)

    Shimakawa, Yuichi

    2015-01-01

    New 134-type perovskites, CaCu 3 Fe 4 O 12 (CCFO) and LaCu 3 Fe 4 O 12 (LCFO), were prepared by means of high-pressure synthesis. The compounds contain unusual high valence Fe 4+ in CCFO and Fe 3.75+ in LCFO at high temperatures. With decreasing temperature, the instabilities of the high valence states of Fe are relieved by distinct charge transitions, which are charge disproportionation (4Fe 4+   →  2Fe 3+   +  2Fe 5+ ) in CCFO and intermetallic charge transfer (3Cu 2+   +  4Fe 3.75+   →  3Cu 3+   +  4Fe 3+ ) in LCFO. Crystal structure analysis with synchrotron x-ray diffraction and magnetic structure analysis with neutron diffraction revealed the nature of the transitions. Although the two behaviors look completely different from each other in simple ionic models, they can both be explained by the localization of ligand holes, which are produced by the strong hybridization of low-lying Fe-d and oxygen p orbitals in the oxides. The ligand holes in the charge disproportionated CCFO are localized at the Fe–O sites alternately (4d 5 L  →  2d 5   +  2d 5 L 2 ) and the ligand holes in the charge transferred LCFO are localized at the Cu–O sites (3d 9   +  4d 5 L 0.75   →  3d 9 L  +  4d 5 ). (review)

  3. Effect of nickel addition on mechanical properties of powder forged Fe-Cu-C

    Science.gov (United States)

    Archana Barla, Nikki

    2018-03-01

    Fe-Cu-C system is very popular in P/M industry for its good compressibility and dimensional stability with high strength. Fe-Cu-C is a structural material and is used where high strength with high hardness is required. The composition of powder metallurgy steel plays a vital role in the microstructure and physical properties of the sintered component. Fe-2Cu-0.7C-Ni alloy with varying nickel composition (0%, 0.5%, 1.0%, 1.5%, 2.0%, and 3.0%) wt. % was prepared by powder metallurgy (P/M) sinter forging process. The present work discuss the effect of varying nickel content on microstructure and mechanical properties.

  4. Influences of annealing temperature on sprayed CuFeO2 thin films

    Science.gov (United States)

    Abdelwahab, H. M.; Ratep, A.; Abo Elsoud, A. M.; Boshta, M.; Osman, M. B. S.

    2018-06-01

    Delafossite CuFeO2 thin films were successfully prepared onto quartz substrates using simple spray pyrolysis technique. Post annealing under nitrogen atmosphere for 2 h was necessary to form delafossite CuFeO2 phase. The effect of alteration in annealing temperature (TA) 800, 850 and 900 °C was study on structural, morphology and optical properties. The XRD results for thin film annealed at TA = 850 °C show single phase CuFeO2 with rhombohedral crystal system and R 3 bar m space group with preferred orientation along (0 1 2). The prepared copper iron oxide thin films have an optical transmission ranged ∼40% in the visible region. The optical direct optical band gap of the prepared thin films was ranged ∼2.9 eV.

  5. Interdiffusion coefficients and atomic mobilities in fcc Cu-Fe-Mn alloys

    Directory of Open Access Journals (Sweden)

    Li J.

    2014-01-01

    Full Text Available In the present work, the interdiffusion coefficients in fcc Cu-Fe-Mn alloys were experimentally determined via a combination of solid/solid diffusion couples, electron probe microanalysis (EPMA technique and Matano-Kirkaldy method. Based on the reliable thermodynamic description of fcc phase in the Cu-Fe-Mn system available in the literature as well as the ternary diffusion coefficients measured in the present work, the atomic mobilities in fcc Cu-Fe-Mn alloys were assessed by utilizing the DICTRA (Diffusion Controlled TRAnsformation software package. The calculated interdiffusion coefficients based on the assessed atomic mobilities agree well with most of the experimental data. The comprehensive comparison between various model-predicted diffusion properties and the measured data, including the concentration penetration profiles, interdiffusion flux profile, and diffusion paths, further verify the reliability of the presently obtained atomic mobilities.

  6. Linear arrangement of nano-scale magnetic particles formed in Cu-Fe-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sung, E-mail: k3201s@hotmail.co [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeda, Mahoto [Department of Materials Engineering (SEISAN), Yokohama National University, 79-5 Tokiwadai, Hodogayaku, Yokohama, 240-8501 (Japan); Takeguchi, Masaki [Advanced Electron Microscopy Group, National Institute for Materials Science (NIMS), Sakura 3-13, Tsukuba, 305-0047 (Japan); Bae, Dong-Sik [School of Nano and Advanced Materials Engineering, Changwon National University, Gyeongnam, 641-773 (Korea, Republic of)

    2010-04-30

    The structural evolution of nano-scale magnetic particles formed in Cu-Fe-Ni alloys on isothermal annealing at 878 K has been investigated by means of transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and field-emission scanning electron microscopy (FE-SEM). Phase decomposition of Cu-Fe-Ni occurred after an as-quenched specimen received a short anneal, and nano-scale magnetic particles were formed randomly in the Cu-rich matrix. A striking feature that two or more nano-scale particles with a cubic shape were aligned linearly along <1,0,0> directions was observed, and the trend was more pronounced at later stages of the precipitation. Large numbers of <1,0,0> linear chains of precipitates extended in three dimensions in late stages of annealing.

  7. Influences on Distribution of Solute Atoms in Cu-8Fe Alloy Solidification Process Under Rotating Magnetic Field

    Science.gov (United States)

    Zou, Jin; Zhai, Qi-Jie; Liu, Fang-Yu; Liu, Ke-Ming; Lu, De-Ping

    2018-05-01

    A rotating magnetic field (RMF) was applied in the solidification process of Cu-8Fe alloy. Focus on the mechanism of RMF on the solid solution Fe(Cu) atoms in Cu-8Fe alloy, the influences of RMF on solidification structure, solute distribution, and material properties were discussed. Results show that the solidification behavior of Cu-Fe alloy have influenced through the change of temperature and solute fields in the presence of an applied RMF. The Fe dendrites were refined and transformed to rosettes or spherical grains under forced convection. The solute distribution in Cu-rich phase and Fe-rich phase were changed because of the variation of the supercooling degree and the solidification rate. Further, the variation in solute distribution was impacted the strengthening mechanism and conductive mechanism of the material.

  8. 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.

  9. Study of dipole interaction in micron-width NiFe/Cu/NiFe/NiO wire using exchange anisotropy

    International Nuclear Information System (INIS)

    Kimura, Takashi; Itagaki, Yoshio; Wakaya, Fujio; Gamo, Kenji

    2001-01-01

    The dipole interaction between a NiFe layer pinned by a NiO and a free NiFe layer in a micron-wide NiFe/Cu/NiFe/NiO wire was studied by changing the direction of the exchange bias from the NiO layer. The effect of the dipole interaction when the exchange bias was perpendicular to the wire axis was larger than that when the exchange bias was parallel to the wire axis, and was consistently explained by the stray field caused by the magnetic charges of the pinned layer. It was demonstrated that this method, using exchange anisotropy, is useful for investigating the dipole interaction between ferromagnetic materials separated by a nonmagnetic material in small-scale magnetic multilayers. [copyright] 2001 American Institute of Physics

  10. Analysis of controlled-mechanism of grain growth in undercooled Fe-Cu alloy

    International Nuclear Information System (INIS)

    Chen Zheng; Liu Feng; Yang Xiaoqin; Shen Chengjin; Fan Yu

    2011-01-01

    Highlights: → In terms of a thermo-kinetic model applicable for micro-scale undercooled Fe-4 at.% Cu alloy, grain growth behavior of the single-phase supersaturated granular grain was investigated. → In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time were determined. → The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process, a transition from kinetic-mechanism to thermodynamic-mechanism and purely thermodynamic-controlled process. - Abstract: An analysis of controlled-mechanism of grain growth in the undercooled Fe-4 at.% Cu immiscible alloy was presented. Grain growth behavior of the single-phase supersaturated granular grains prepared in Fe-Cu immiscible alloy melt was investigated by performing isothermal annealings at 500-800 deg. C. The thermo-kinetic model [Chen et al., Acta Mater. 57 (2009) 1466] applicable for nano-scale materials was extended to the system of micro-scale undercooled Fe-4 at.% Cu alloy. In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, two characteristic annealing time (t 1 and t 2 ) were determined. The controlled-mechanism of grain growth in undercooled Fe-Cu alloy was proposed, including a mainly kinetic-controlled process (t ≤ t 1 ), a transition from kinetic-mechanism to thermodynamic-mechanism (t 1 2 ) and purely thermodynamic-controlled process (t ≥ t 2 ).

  11. Thermodynamic investigations of the quasi-2d triangular Heisenberg antiferromagnet Cs{sub 2}CuCl{sub 2}Br{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tutsch, Ulrich; Postulka, Lars; Wolf, Bernd; Lang, Michael; Well, Natalija van; Ritter, Franz; Krellner, Cornelius; Assmus, Wolf [Physikalisches Institut, Goethe-University Frankfurt (Germany)

    2015-07-01

    The system Cs{sub 2}CuCl{sub 4-x}Br{sub x} (0 ≤ x ≤ 4) is a quasi-two-dimensional Heisenberg antiferromagnet with a triangular in-plane arrangement of the spin-spin couplings. The ratio J{sup '}/J of the corresponding coupling constants determines the degree of frustration in the system and has been found to be 0.34 (x = 0) and 0.74 (x = 4) for the border compounds. One may ask whether for some intermediate Br concentration an even higher degree of frustration can be reached. Indeed, some indications have been reported by Ono et al. Here, we present specific heat C and susceptibility χ measurements below 1 K in magnetic fields B up to 13.5 T for the intermediate compound Cs{sub 2}CuCl{sub 2}Br{sub 2}, which, due to site-selective substitution, shows a well-ordered halide sublattice. Indications for an antiferromagnetic transition are observed around 90 mK for B = 0. A small field of B = 0.14 T is sufficient to fully suppress this anomaly. Taking into account the high saturation field of about 20 T, extrapolated from χ(T = const, B) scans at low temperatures, this small ordered region in the B-T plane clearly indicates a high degree of frustration in Cs{sub 2}CuCl{sub 2}Br{sub 2}.

  12. The Reaction Mechanism and Rate Constants in the Radiolysis of Fe2+-Cu2+ Solutions

    DEFF Research Database (Denmark)

    Bjergbakke, Erling; Sehested, Knud; Rasmussen, O. Lang

    1976-01-01

    Pulse radiolysis and gamma radiolysis have been used to study the reaction mechanism in the radiolysis of aqueous solutions of Fe2+ and Cu2+. A reaction scheme has been developed and confirmed by computation of the corresponding complete set of differential equations. The rate constants for some ...... 10^{8}$ and $1.3\\times 10^{8}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$ in pH 2.1 H2 SO4 and HClO4, respectively.......Pulse radiolysis and gamma radiolysis have been used to study the reaction mechanism in the radiolysis of aqueous solutions of Fe2+ and Cu2+. A reaction scheme has been developed and confirmed by computation of the corresponding complete set of differential equations. The rate constants for some...... of the reactions have been determined at different pH's. $k_{{\\rm Cu}^{+}+{\\rm O}_{2}}=4.6\\times 10^{5}$ and $1.0\\times 10^{6}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$, $k_{{\\rm Cu}^{+}+{\\rm Fe}^{3+}}=5.5\\times 10^{6}$ and $1.3\\times 10^{7}\\ {\\rm mol}^{-1}\\ {\\rm sec}^{-1}$, $k_{{\\rm Cu}({\\rm III)}+{\\rm Fe}^{2+}}=3.3\\times...

  13. Determination of Ca, Fe, Cu and Zn content in hair by EDXRF method

    International Nuclear Information System (INIS)

    Yang Mingtai; Chen Jinhua; Qi Honglian; Gao Ge

    1994-01-01

    The authors introduce an analysing method that can determine simultaneously Ca, Fe, Cu and Zn in hair by using energy-dispersive X ray fluorescence analyzer of tube-excite type made in China. The added element Y is used as internal standard in hair sample. The hair is resolved by chemical reagent to make test sample, then the energy-dispersive X ray fluorescence analyzer is used to determine Ca, fe, Cu and Zn contents in hair sample. The lower limits of detection are 7 x 10 -6 , 1 x 10 -6 , 4 x 10 -6 , 3 x 10 -6 , respectively. Correlative coefficients of variations are 6%, 1%, 2%, 2%

  14. The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

    OpenAIRE

    Travessa, Dilermando Nagle; Cardoso, Kátia Regina; Wolf, Witor; Jorge Junior, Alberto Moreira; Botta, Walter José

    2012-01-01

    In order to obtain quasicrystalline (QC) phase by mechanical alloying (MA) in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. %) were produced by high energy ball milling (HEBM). A very high energy type mill (spex) and short milling times (up to 5 hours) were employed. The resulting powders were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). QC phase was not directly formed ...

  15. Integrated photooxidative-extractive desulfurization system for fuel oil using Cu, Fe and Cu-Fe/TiO2 and eutectic based ionic liquids: Effect of calcination temperature and duration

    Science.gov (United States)

    Zaid, Hayyiratul Fatimah Mohd; Kait, Chong Fai; Mutalib, Mohamed Ibrahim Abdul

    2014-10-01

    Photocatalyts TiO2 doped with Cu, Fe and Cu-Fe metal at different calcination temperature and duration were successfully prepared and characterized. Photocatalytic oxidative desulfurization of model oil containing dibenzothiophene as the sulfur compound (100 ppm) using the prepared photocatalyst was investigated. The photocatalyst calcined at 500°C and duration of 1 h showed the best performance.

  16. Electrical characteristic of spin coated Fe-Porphyrin on Cu substrates

    Energy Technology Data Exchange (ETDEWEB)

    Utari, E-mail: utari@ugm.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Kusumandari,; Purnama, Budi, E-mail: bpurnama@mipa.uns.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami 36A Kentingan Surakarta 57126 (Indonesia); Mudasir [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia); Abraha, Kamsul [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Bulaksumur BLS 21 Yogyakarta 55281 (Indonesia)

    2016-06-17

    This paper describes the electrical-characteristics of Fe-Porphyrin thin films on Cu substrates. The thin layer samples used were deposited by spin coating methods on Cu-substrates at room temperature with and without induced magnetic field in the plane direction of the surface films. Fe-porphyrin was dissolved in chloroform and mixed with a magnetic stirrer for 60 min at a rotational speed of 200 rpm. The experimental results show that the mobility carrier charge of the Fe-Porphyrin layer with induced magnetic field during deposition has lower value than that without induced magnetic field case. The decrease of the mobility can be attribute to the change of the surface morphology in Fe-porphyrin films by means of increase in the nano-granular/nano-molecular size caused by the induce magnetic field.

  17. Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

    International Nuclear Information System (INIS)

    Sitek, J.; Toth, I.; Miglierini, M.

    1993-01-01

    Amorphous ribbons of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 μm and 27 μm were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO 3 -structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO 3 -structure FeSi alloy, paramagnetic FeNbB and presumably Fe 23 B 6 and Fe 3 SiB 2 . (orig.)

  18. Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

    Science.gov (United States)

    Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  19. 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+).

  20. Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, A.S.; Buznikov, N.A. E-mail: n_buznikov@mail.ru; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M

    2002-08-01

    The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors.

  1. Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

    International Nuclear Information System (INIS)

    Antonov, A.S.; Buznikov, N.A.; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M.

    2002-01-01

    The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors

  2. First-principles-based study of transport properties of Fe thin films on Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kishi, Tomoya [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Kasai, Hideaki [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Nakanishi, Hiroshi [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Dino, Wilson Agerico [Department of Applied Physics, Osaka University, Suita, Osaka 565-0871 (Japan); Komori, Fumio [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8587 (Japan)

    2004-12-08

    We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties.

  3. First-principles-based study of transport properties of Fe thin films on Cu surfaces

    International Nuclear Information System (INIS)

    Kishi, Tomoya; Kasai, Hideaki; Nakanishi, Hiroshi; Dino, Wilson Agerico; Komori, Fumio

    2004-01-01

    We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties

  4. Novel La(Fe,Si){sub 13}/Cu composites for magnetic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lyubina, Julia; Hannemann, Ullrich; Ryan, Mary P. [Department of Materials, Imperial College London, London, SW7 2AZ (United Kingdom); Cohen, Lesley F. [Department of Physics, Imperial College London, London, SW7 2AZ (United Kingdom)

    2012-11-15

    An approach to engineering magnetic refrigerant materials with defined thermal transport properties is demonstrated using the example of high magnetocaloric performance La-Fe-Si alloys. A tunability of up to 300% of the thermal conductivity can be achieved in composites consisting of a La(Fe,Si){sub 13} compound and Cu prepared by electroless copper plating without compromising the magnitude of the magnetocaloric effect. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Electrical resistivity of nanocrystals in Fe-Al-Ga-P-B-Si-Cu alloy

    International Nuclear Information System (INIS)

    Pekala, K.; Jaskiewicz, P.; Nowinski, J.L.; Pekala, M.

    2003-01-01

    In new supercooled Fe 74 Al 4 Ga 2 P 11 B 4 Si 4 Cu 1 alloy the 10 nm size α-Fe(Si) nanocrystals are precipitated. Thermal stability is analyzed by the electron transport and magnetization measurements. Temperature variation of electrical resistivity of nanocrystals is determined and discussed for alloys with different initial crystalline fraction. Possible mechanism inhibiting the grain growth is presented

  6. Charge compensation and magnetic properties in Sr and Cu doped La-Fe perovskites

    Directory of Open Access Journals (Sweden)

    de Julián Fernández C.

    2013-01-01

    Full Text Available Orthorhombic lanthanum orthoferrites La0.8Sr0.2Fe1-yCuyO3-w (y = 0 and 0.10 have been studied using X-rays and neutron powder diffraction (XRPD and NPD, magnetization measurements and 57Fe Mössbauer spectroscopy. Rietveld refinements on XRPD and NPD data show that they adopt an orthorhombic ABO3 perovskite symmetry with La/Sr and Fe/Cu atoms randomly distributed on crystal A and B sites, respectively. The magnetic structure at room temperature is antiferromagnetic, with the Fe/Cu magnetic moments aligned along the a axis. Magnetization curves versus temperature show that the compounds exhibit an overall antiferromagnetic and a weak ferromagnetic behaviour in the range 5-298 K. 57Fe Mössbauer spectroscopy measurements indicate that Fe3+ and Fe5+ ions coexist in both compounds, and the relative percentage of Fe5+ is almost the same at 77 and 170 K, rejecting a charge disproportion mechanism.

  7. 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...

  8. Formation of the 1:2:3 structure in Y-Ba-Cu(Fe)-O system studied by Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Valko, P.; Miglierini, M.; Sitek, J.; Hucl, M.; Gruskova, A.

    1990-01-01

    Annealing time and temperature dependence of Y, Ba, Cu, Fe nitrade mixture towards new phases creation was revealed by Moessbauer spectroscopy. The observed changes can be assigned to chemical decomposition of corresponding nitrades and creation of intermedial and final Y 1 Ba 2 (Cu 0.95 Fe 0.05 ) 3 O x phase. (orig.)

  9. Rietveld refinement of the mixed boracite Fe1.59Zn1.41B7O13Br

    Directory of Open Access Journals (Sweden)

    Sandra Ulloa-Godínez

    2009-11-01

    Full Text Available The structural characterization of the new iron–zinc heptaborate bromide with composition Fe1.59Zn1.41B7O13Br, 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 interatomic 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 tetrahedrally 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 tetrahedral 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.

  10. 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

    2009-10-31

    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.

  11. Sorption Mechanisms of Cesium on Cu II2Fe II(CN) 6and Cu II3[Fe III(CN) 6] 2Hexacyanoferrates and Their Relation to the Crystalline Structure

    Science.gov (United States)

    Ayrault, S.; Jimenez, B.; Garnier, E.; Fedoroff, M.; Jones, D. J.; Loos-Neskovic, C.

    1998-12-01

    CuII2FeII(CN)6·xH2O and CuII3[FeIII(CN)6]2·xH2O can be prepared with reproducible chemical compositions and structures after careful washing. They have cubicFmoverline3mstructures with iron vacancies. In CuII2FeII(CN)6, copper occupies two different sites: Cu1 in position 4blinked to Fe through the CN groups, and Cu2 not linked to the CN groups and partially occupying the interstitial 24epositions. The second type of site is not present in CuII3[FeIII(CN)6]2. Sorption kinetics and isotherms were determined for cesium on both hexacyanoferrates by batch experiments. On CuII3[FeIII(CN)6]2, the maximum uptake is only 0.073 Cs/Fe (at./at.). On CuII2FeII(CN)6, the uptake reaches 1.5 Cs/Fe. The sorption kinetics include at least two steps: at1/2variation until approximately 72 h and then a slow evolution studied up to 6 months. The sorption mechanism is complex. The main process seems to be diffusion of ion pairs, followed by a reorganization of the solid, resulting in one or more new solid phases. The presence of the Cu2 site seems to play a favorable role in the sorption. Owing to its good midterm stability and the first rapid step of exchange, CuII2FeII(CN)6·xH2O seems to be one of the most promising compounds for the recovery of cesium from nuclear liquid wastes.

  12. Effects of Cu substitution for Fe on the glass-forming ability and soft magnetic properties for Fe-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Dou, Lintao; Liu, Haishun; Hou, Long; Xue, Lin; Yang, Weiming; Zhao, Yucheng; Chang, Chuntao

    2014-01-01

    The effects of Cu substitution for Fe on the glass-forming ability (GFA) and soft magnetic properties for Fe 72−x Cu x B 20 Si 4 Nb 4 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) bulk metallic glasses (BMGs) are investigated. It is found that the investigated BMGs exhibit large GFA as well as excellent soft magnetic properties, and proper substitution of Fe by Cu improves the saturation magnetization, coercive force, and effective permeability without obvious deterioration of the GFA. - Highlights: • Fully glassy rods of Fe 72−x Cu x B 20 Si 4 Nb 4 BMGs were produced above 1 mm in diameter. • Investigated BMGs exhibit large glass-forming ability and excellent soft magnetic properties. • Proper Cu substitution improves magnetic properties without obvious deterioration of glass-forming ability

  13. 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.

  14. 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.

  15. Influence of the spacer layer on microstructure and magnetic properties of [NdFeB/(NbCu)]xn thin films

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-15

    Some results concerning the influence of the composition and thickness of NbCu spacer layer on the microstructure and magnetic properties of multilayer [NdFeB/(NbCu)]xn films, in view of their utilization for manufacturing the thin film permanent magnets are presented. A comparison between the microstructure and magnetic properties of NdFeB single layer and [NdFeB/(NbCu)]xn multilayer is also presented. The multilayer [NdFeB/(NbCu)]xn thin films with the thickness of the NdFeB layer of 180nm and the thickness of the NbCu spacer layer of 3nm, exhibit good hard magnetic characteristics such as coercive force H{sub c} of about 1510kA/m and the remanence ratio M{sub r}/M{sub s} of about 0.8.

  16. Influence of the spacer layer on microstructure and magnetic properties of [NdFeB/(NbCu)]xn thin films

    International Nuclear Information System (INIS)

    Chiriac, H.; Grigoras, M.; Urse, M.

    2007-01-01

    Some results concerning the influence of the composition and thickness of NbCu spacer layer on the microstructure and magnetic properties of multilayer [NdFeB/(NbCu)]xn films, in view of their utilization for manufacturing the thin film permanent magnets are presented. A comparison between the microstructure and magnetic properties of NdFeB single layer and [NdFeB/(NbCu)]xn multilayer is also presented. The multilayer [NdFeB/(NbCu)]xn thin films with the thickness of the NdFeB layer of 180nm and the thickness of the NbCu spacer layer of 3nm, exhibit good hard magnetic characteristics such as coercive force H c of about 1510kA/m and the remanence ratio M r /M s of about 0.8

  17. Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhengru, E-mail: zhengruzhu@gmail.com [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China); State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Xinyong; Zhao, Qidong [State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Yonghua; Sun, Caizhi; Cao, Yongqiang [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China)

    2013-08-01

    Graphical abstract: - Highlights: • CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

  18. Oxidative degradation of the antibiotic oxytetracycline by Cu@Fe3O4 core-shell nanoparticles.

    Science.gov (United States)

    Pham, Van Luan; Kim, Do-Gun; Ko, Seok-Oh

    2018-08-01

    A core-shell nanostructure composed of zero-valent Cu (core) and Fe 3 O 4 (shell) (Cu@Fe 3 O 4 ) was prepared by a simple reduction method and was evaluated for the degradation of oxytetracycline (OTC), an antibiotic. The Cu core and the Fe 3 O 4 shell were verified by X-ray diffractometry (XRD) and transmission electron microscopy. The optimal molar ratio of [Cu]/[Fe] (1/1) in Cu@Fe 3 O 4 created an outstanding synergic effect, leading to >99% OTC degradation as well as H 2 O 2 decomposition within 10min at the reaction conditions of 1g/L Cu@Fe 3 O 4 , 20mg/L OTC, 20mM H 2 O 2 , and pH3.0 (and even at pH9.0). The OTC degradation rate by Cu@Fe 3 O 4 was higher than obtained using single nanoparticle of Cu or Fe 3 O 4 . The results of the study using radical scavengers showed that OH is the major reactive oxygen species contributing to the OTC degradation. Finally, good stability, reusability, and magnetic separation were obtained with approximately 97% OTC degradation and no notable change in XRD patterns after the Cu@Fe 3 O 4 catalyst was reused five times. These results demonstrate that Cu@Fe 3 O 4 is a novel prospective candidate for the pharmaceutical and personal care products degradation in the aqueous phase. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films

    DEFF Research Database (Denmark)

    Szymczewska, Dagmara; Molin, Sebastian; Hendriksen, Peter Vang

    2017-01-01

    In this work, thin films (~1000 nm) of a pure MnCo2O4 spinel together with its partially substituted derivatives (MnCo1.6Cu0.2Fe0.2O4, MnCo1.6Cu0.4O4, MnCo1.6Fe0.4O4) were prepared by spray pyrolysis and were evaluated for electrical conductivity. Doping by Cu increases the electrical conductivit...

  20. Study of the C-14-contamination potential of C-impurities in CuO and Fe

    NARCIS (Netherlands)

    Vandeputte, K; Moens, L; Dams, R; van der Plicht, Johannes

    1998-01-01

    The carbon concentration in CuO and iron was determined by isolating C. The values were in agreement with results reported in other studies. Contaminating carbon from CuO and Fe was transformed to AMS targets and measured for C-14. C-traces in CuO were shown to be the major contribution to the C-14

  1. Levels Of Mn, Fe, Ni, Cu, Zn And Cd, In Effluent From A Sewage ...

    African Journals Online (AJOL)

    This study reports the results of preliminary investigation of heavy metal levels-Ni, Cd, Fe, Zn, Cu and Mn; pH; temperature and electrical conductivity in effluents from a sewage treatment oxidation pond and its receiving stream. The heavy metal concentrations were determined with Inductively Coupled Plasma-Mass ...

  2. Equilibrium Sorption studies of Fe, Cu and Co ions in aqueous ...

    African Journals Online (AJOL)

    Recinius Communis Linn a commonly found herbal plant was used to prepare activated carbon by physicochemical activation method. The sorption capacity of this bio-resource material to remove Fe(III), Cu(II) and Co(II) from aqueous solutions was determined by batch tests. The influences of important parameters such as ...

  3. Room temperature deposition of amorphous p-type CuFeO2 and ...

    Indian Academy of Sciences (India)

    2Key Lab of Novel Thin Film Solar Cells, Chinese Academy of Sciences, Hefei 230031, China. 3University of Science and Technology of China, Hefei 230026, China. MS received 14 October 2015; accepted 28 December 2015. Abstract. Transparent conducting amorphous p-type CuFeO2 (CFO) thin film was prepared by ...

  4. Adsorption of pentane isomers on metal-organic frameworks Cu-BTC and Fe-BTC

    Czech Academy of Sciences Publication Activity Database

    Zukal, Arnošt; Opanasenko, Maksym; Rubeš, M.; Nachtigall, P.; Jagiello, J.

    2015-01-01

    Roč. 243, APR 2014 (2015), s. 69-75 ISSN 0920-5861 R&D Projects: GA ČR GA14-07101S Institutional support: RVO:61388955 Keywords : Cu-BTC * Fe-BTC * adsorption Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.312, year: 2015

  5. The geochemical profile of Mn, Co, Cu and Fe in Kerteh Mangrove Forest, Terengganu

    International Nuclear Information System (INIS)

    Kamaruzzaman, B.Y.; Antotina, A.; Airiza, Z.; Syalindran, S.; Ong, M.C.

    2007-01-01

    The geochemical profile of Kerteh mangrove sediments was analyzed for the vertical and horizontal distribution. The 100 cm core sediment sample and 15 surface sediments samples were taken from the field. The geochemical elements of Mn, Co, Cu and Fe of the sediments were analyzed. Geochemical proxy of Mn, Co, Cu and Fe were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The mean concentrations of Mn, Co, Cu and Fe for the vertical distribution were 210.18 μg/ g, 15.55 μg/ g, 43.65 μg/ g and 1.88 μg/ g respectively. on the other hand, the mean concentrations of the geochemical elements for horizontal distributions were 230.50 μg/ g for Mn, 17.57 μg/ g for Co, 43.381 μg/ g for Cu and 2.93 μg/ g for Fe. Enrichment factor and normalization was used to point out the level of pollution. The EF and the normalization indicated that all the geochemical elements were from the natural sources. (author)

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

    KAUST Repository

    Heryadi, Dodi; Schwingenschlö gl, Udo

    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

  7. Microwave catalytic NOx and SO{sub 2} removal using FeCu/zeolite as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Z.S. Wei; G.H. Zeng; Z.R. Xie; C.Y. Ma; X.H. Liu; J.L. Sun; L.H. Liu [Sun Yat-sen University, Guangzhou (China). School of Environmental Science and Engineering

    2011-04-15

    Non-thermal plasma technology is a promising process for flue gas treatment. Microwave catalytic NOx and SO{sub 2} removal simultaneously has been investigated using FeCu/zeolite as catalyst. The experimental results showed that a microwave reactor with FeCu/zeolite only could be used to microwave catalytic oxidative 91.7% NOx to nitrates and 79.6% SO{sub 2} to sulfate; the reaction efficiencies of microwave catalytic reduction of NOx and SO{sub 2} in a microwave reactor with FeCu/zeolite and ammonium bicarbonate (NH{sub 4}HCO{sub 3}) as a reducing agent could be up to 95.8% and 93.4% respectively. Microwave irradiation accentuates catalytic reduction of SO{sub 2} and NOx treatment, and microwave addition can increases SO{sub 2} removal efficiency from 14.5% to 18.7%, and NOx removal efficiency from 13.4% to 18.7%, separately. FeCu/zeolite catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectrum analysis (XPS), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic NOx and SO{sub 2} removal follows Langmuir-Hinshelwood (L-H) kinetics. 25 refs., 7 figs., 1 tab.

  8. Batch adsorption of heavy metals (Cu, Pb, Fe, Cr and Cd) from ...

    African Journals Online (AJOL)

    cinthia

    This study was carried out to evaluate the efficiency of metals (Cu, Fe, Pb, Cr and Cd) removal from mixed metal ions solution using coconut husk as adsorbent. The effects of varying contact time, initial metal ion concentration, adsorbent dose and pH on adsorption process of these metals were studied using synthetically ...

  9. SIMULATION OF ION-BEAM CHANNELING IN ICOSAHEDRAL AL63CU25FE12

    NARCIS (Netherlands)

    VANVOORTHUYSEN, EHD; SMULDERS, PJM; VANSMAALEN, S

    1993-01-01

    Monte Carlo simulations of channeling on the icosahedral quasicrystal Al63Cu25Fe12 were made, using an experimentally determined structure model for this phase. The channeling effect was found to be nearly as good as for a normal, periodic crystal. Dip widths are in agreement with experimental

  10. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Partitioning of Cu between mafic minerals, Fe-Ti oxides and intermediate to felsic melts

    Science.gov (United States)

    Liu, Xingcheng; Xiong, Xiaolin; Audétat, Andreas; Li, Yuan

    2015-02-01

    This study used improved capsule technique i.e., Pt95Cu05 or Au95Cu05 alloy capsules as Cu sources to determine Cu partitioning between mafic minerals, Fe-Ti oxides and intermediate to felsic melts at 0.5-2.5 GPa, 950-1100 °C and various oxygen fugacities (fO2). In combination with the data from the mafic composition systems, the results demonstrate that Cu is generally highly incompatible in mafic minerals and moderately incompatible to compatible in Fe-Ti oxides. The general order of mineral/melt Cu partition coefficients (DCu) is garnet (0.01-0.06) ⩽ olivine (0.04-0.20) ≈ opx (0.04-0.24) ≈ amphibole (0.04-0.20) ⩽ cpx (0.04-0.45) ⩽ magnetite, titanomagnetite and Cr-spinel (0.18-1.83). The variations in DCu depend mainly on temperature, fO2 or mineral composition. In general, DCu for olivine (and perhaps opx) increases with decreasing temperature and increasing fO2. DCu increases for cpx with Na+ (pfu) in cpx, for magnetite and Cr-spinel with Fe3+ (pfu) in these phases and for titanomagnetite with Ti4+ (pfu) in this phase. The large number of DCu data (99 pairs) serves as a foundation for quantitatively understanding the behavior of Cu during magmatic processes. The generation of intermediate to felsic magmas via fractional crystallization or partial melting of mafic rocks (magmas) at deep levels of crust involves removal of or leaving assemblages of mafic minerals + Fe-Ti oxides ± sulfides. With our DCu data on mafic minerals and Fe-Ti oxides, DCubulk values around 0.2 were obtained for the sulfide-free assemblages. Cu will thus be concentrated efficiently in the derived melts during these two processes if sulfides are absent or negligible, explaining that high fO2 and sulfide-destabilization are favorable to formation of the porphyry Cu system.

  12. Responses of mixed methanotrophic consortia to variable Cu2+/Fe2+ ratios.

    Science.gov (United States)

    Chidambarampadmavathy, Karthigeyan; Karthikeyan, Obulisamy Parthiba; Huerlimann, Roger; Maes, Gregory E; Heimann, Kirsten

    2017-07-15

    Methane mitigation in landfill top cover soils is mediated by methanotrophs whose optimal methane (CH 4 ) oxidation capacity is governed by environmental and complex microbial community interactions. Optimization of CH 4 remediating bio-filters need to take microbial responses into account. Divalent copper (Cu 2+ ) and iron (Fe 2+ ) are present in landfills at variable ratios and play a vital role in methane oxidation capacity and growth of methanotrophs. This study, as a first of its kind, therefore quantified effects of variable Cu 2+ and Fe 2+ (5:5, 5:25 and 5:50 μM) ratios on mixed methanotrophic communities enriched from landfill top cover (LB) and compost soils (CB). CH 4 oxidation capacity, CH 4 removal efficiencies, fatty acids content/profiles and polyhydroxybutyrate (PHB; a biopolymer) contents were also analysed to quantify performance and potential co-product development. Mixed methanotroph cultures were raised in 10 L continuous stirred tank reactors (CSTRs, Bioflo ® & Celligen ® 310 Fermentor/Bioreactor; John Morris Scientific, Chatswood, NSW, Australia). Community structure was determined by amplifying the V3-V4 region of 16s rRNA gene. Community structure and, consequently, fatty acid-profiles changed significantly with increasing Cu 2+ /Fe 2+ ratios, and responses were different for LB and CB. Effects on methane oxidation capacities and PHB content were similar in the LB- and CB-CSTR, decreasing with increasing Cu 2+ /Fe 2+ ratios, while biomass growth was unaffected. In general, high Fe 2+ concentration favored growth of the type -II methanotroph Methylosinus in the CB-CSTR, but methanotroph abundances decreased in the LB-CSTR. Increase in Cu 2+ /Fe 2+ ratio increased the growth of Sphingopyxis in both systems, while Azospirllum was co-dominant in the LB- but absent in the CB-CSTR. After 13 days, methane oxidation capacities and PHB content decreased by ∼50% and more in response to increasing Fe 2+ concentrations. Although methanotroph

  13. Intermartensitic transitions in Ni-Mn-Fe-Cu-Ga Heusler alloys

    International Nuclear Information System (INIS)

    Khan, Mahmud; Gautam, Bhoj; Pathak, Arjun; Dubenko, Igor; Stadler, Shane; Ali, Naushad

    2008-01-01

    A series of Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga Heusler alloys have been investigated by means of x-ray diffraction, magnetizations, thermal expansion, and electrical resistivity measurements. In Ni 2 Mn 0.75 Cu 0.25 Ga, martensitic and ferromagnetic transitions occur at the same temperature. Partial substitution of Mn by Fe results in a decrease of the martensitic transition temperature, T M , and an increase of the ferromagnetic transition temperature, T C , resulting in separation of the two transitions. In addition to the martensitic transition, complete thermoelastic intermartensitic transformations have been observed in the Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga samples with x>0.04. An unusual transition is observed in the alloy with x = 0.04. The magnetization curve as a function of increasing temperature shows only one first-order transition in the temperature range 5-400 K, which is identified as a typical coupled magnetostructural martensitic transformation. The magnetization curve as a function of decreasing temperature shows three different transitions, which are characterized as the ferromagnetic transition, the martensitic transition and the intermartensitic transition.

  14. Magnetic and catalytic properties of inverse spinel CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Anandan, S., E-mail: sanand@nitt.edu [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China); Selvamani, T.; Prasad, G. Guru [Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Trichy 620 015 (India); Asiri, A.M. [The Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21413 (Saudi Arabia); Wu, J.J., E-mail: jjwu@fcu.edu.tw [Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan (China)

    2017-06-15

    Highlights: • Copper ferrite (CuFe{sub 2}O{sub 4}) nanoparticles were synthesized via citrate-nitrate combustion method. • Spectroscopic information’s have found that CuFe{sub 2}O{sub 4} nanoparticles as an inverse spinel structure. • Magnetic study exhibits CuFe{sub 2}O{sub 4} nanoparticles have ferromagnetic behavior. • CuFe{sub 2}O{sub 4} nanoparticles employed for photocatalytic decolourisation of methylene blue under visible light irradiation. - Abstract: In this research, inverse spinel copper ferrite nanoparticles (CuFe{sub 2}O{sub 4} NPs) were synthesized via citrate-nitrate combustion method. The crystal structure, particle size, morphology and magnetic studies were investigated using various instrumental tools to illustrate the formation of the inverse spinel structure. Mossbauer spectrometry identified Fe is located both in the tetrahedral and octahedral site in the ratio (40:60) and the observed magnetic parameters values such as saturation magnetization (M{sub s} = 20.62 emu g{sup −1}), remnant magnetization (M{sub r} = 11.66 emu g{sup −1}) and coercivity (H{sub c} = 63.1 mTesla) revealed that the synthesized CuFe{sub 2}O{sub 4} NPs have a typical ferromagnetic behaviour. Also tested CuFe{sub 2}O{sub 4} nanoparticles as a photocatalyst for the decolourisation of methylene blue (MB) in the presence of peroxydisulphate as the oxidant.

  15. Spontaneous piezoelectric effect as order parameter in (NH{sub 4}){sub 2}CuBr{sub 4}·2H{sub 2}O crystal

    Energy Technology Data Exchange (ETDEWEB)

    Tylczyński, Z., E-mail: zbigtyl@amu.edu.pl; Wiesner, M.; Trzaskowska, A.

    2016-11-01

    Temperature change of piezoelectric properties of (NH{sub 4}){sub 2}CuBr{sub 4}·2H{sub 2}O crystal in the low-temperature ferroelastoelectric phase is studied. The macroscopic order parameter is proved to be the h{sub 36} component of the spontaneous piezoelectric tensor. The critical exponent related with the phase transition is α=0.60±0.05.

  16. Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

    International Nuclear Information System (INIS)

    Du, Jiandi; Ding, Dongyan; Xu, Zhou; Zhang, Junchao; Zhang, Wenlong; Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua; Chen, Renzong; Huang, Yuanwei; Tang, Jinsong

    2017-01-01

    Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al 8 Cu 4 Ce phase, Al 6 Cu 6 La phase and Al 6 (Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al 8 Cu 4 Ce and Al 6 Cu 6 La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al 20 Cu 2 Mn 3 and Al 6 (Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

  17. Microstructure and corrosion resistance of Sm-containing Al-Mn-Si-Fe-Cu alloy

    Directory of Open Access Journals (Sweden)

    Han Yuyin

    2017-12-01

    Full Text Available Optimizing alloy composition is an effective way to improve physical and chemical properties of automobile heat exchanger materials.A Sm-containing Al-Mn-Si-Fe-Cu alloy was investigated through transmission electron microscopy,scanning electron microscopy,and electrochemical measurement.Experimental results indicated that main phases distributed in the alloy wereα-Al(Mn,FeSi,Al2Sm and Al10Cu7Sm2.Alloying with Sm element could refine the precipitated α-Al(Mn,FeSi phase.Polarization testing results indicated that the corrosion surfacewas mainly composed of pitting pits and corrosion products.Sea water acetic acid test(SWAAT showed that corrosion loss increased first and then slowed downwith increase of the corrosion time.

  18. Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems

    Directory of Open Access Journals (Sweden)

    Reni George

    2014-03-01

    Full Text Available A series of spinels having thegeneral formula CuCr2-xFexO4 with x=0.25,0.75, 1.25, 1.75 were prepared by co-precipitation method. The catalysts werecharacterized by various physico-chemical methods like XRD, BET, UV-DRS, SEM,EDX, TPD etc. The reaction of aniline with methanol was studied in a fixed-bedreactor system as a potential source for the production of various methylanilines. It was observed that systems possessing low ‘x’ values are highlyselective and active for N-monoalkylation of aniline leading toN-methylaniline. Reaction parameters were properly varied to optimize thereaction conditions for obtaining N-methylaniline selectively and in betteryield. Among the systems CuCr1.75Fe0.25O4 isremarkable due to its very high activity and excellent stability. Under theoptimized conditions N-methylaniline selectivity exceeded 91%. CuCr1.25Fe0.75O4gives better conversion than CuCr1.75Fe0.25O4in CuCr2-xFexO4 series. The Lewis acid sitesof the catalysts are mainly responsible for the good catalytic performance. © 2014 BCREC UNDIP. All rights reservedSubmitted: 18th July 2013; Revised: 5th November 2013; Accepted: 1st December 2013[How to Cite: George, R., George, K., Sugunan, S. (2014. Activity of Aniline Methylation over Fe-Cu-Cr Ternary Spinel Systems. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 39-44. (doi:10.9767/bcrec.9.1.5169.39-44][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5169.39-44] 

  19. Mecano-synthesis of the alloy 25%Fe-50%Cu-25%Nb; Mecano-sintese da liga 25%Fe-50%Cu-25%Nb

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Keytiane; Oliveira, Michel Picanco de; Guimaraes, Renan da Silva; Moreira Junior, Valdenir; Filgueira, Marcello, E-mail: marcello.filgueira@pq.cnpq.br [Universidade Estadual do Norte Fluminense (CCT/LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil)

    2016-07-01

    In general, this study aims at the application of mechanical grinding to the system 25% Fe-50% Cu-25% Nb and studies the production process of these powders during milling. The evolution of the structure during the synthesis and the effect of variation of the grinding time were studied by diffraction of X-rays (XRD) and Scanning Electron Microscopy coupled EDS (SEM + EDS) in order to obtain the sizes of crystallites, the phase formation and its evolution with grinding time, and also the homogeneity of the mixture. The particle size distribution was analyzed by laser sedigraph technique. The powders synthesis were performed for milling time of 2.5, 5 and 10 hours. The mechanical grinding showed to be effective with the solid solution formation in the early grinding times. The XRD showed the solid solution formation with subsequent reduction and disappearance of Cu peaks. Through the technique of laser sedigraph it was observed the increase of the particle size followed by the its reduction in the milling time of 10h, a fact that characterizes the mechanical grinding process for ductile powder particles. Thus, the study demonstrated the effectiveness of the mechanical grinding to obtain powder of Fe-Cu-Nb and further processing and application of diamond cutting tools. (author)

  20. The evaluation of Young's modulus and residual stress of Cu films by NiFe/Cu bilayer film microbridge tests

    International Nuclear Information System (INIS)

    Zhou Zhimin; Zhou Yong; Cao Ying; Ding Wen; Mao Haiping

    2008-01-01

    This paper proposes a method to estimate the thickness limit for single-layer microbridge tests and also the thickness limit of one film on another film with known thickness for bilayer microbridge tests. To evaluate the mechanical properties of the Cu film, which could not be measured by single-layer microbridge tests, the NiFe single-layer film and NiFe/Cu bilayer film on silicon substrate are fabricated onto the microbridge by the MEMS technique. A load–deflection experiment is conducted upon the ceramic shaft adhered to the microbridge center by means of the XP nanoindenter system. From single-layer microbridge theory, Young's modulus and the residual stress of the NiFe film are deduced to be 192.74 ± 8.10 GPa and 287.75 ± 16.18 MPa, respectively. The data are introduced into bilayer microbridge theory and Young's modulus and the residual stress of the copper film are calculated to be 118.71 ± 6.54 GPa and 41.34 ± 4.42 MPa, respectively. The experimental results correspond well with those of nanoindentation

  1. Phase diagram of pressure-induced superconductor β-(BDA-TTP)2MX4 (M=Fe, Ga and X=Cl, Br) with localized magnetic moments

    Science.gov (United States)

    Choi, E. S.; Graf, D.; Tokumoto, T.; Brooks, J. S.; Yamada, Jun-Ichi

    2007-03-01

    We have investigated transport and magnetization properties of β-(BDA-TTP)2MX4 (M=Fe, Ga and X=Cl, Br) as a function of pressure, temperature and magnetic field. The title material undergoes metal-insulator transitions above 100 K at ambient pressure. The insulating phase is suppressed with pressure and superconductivity eventually appears above Pc= 4.5 kbar (X=Cl) and 13 kbar (X=Br). The general temperature-pressure (TP) phase diagram is similar each other, while higher pressure is required for X=Br compounds to suppress the insulating state and induce the superconductivity. Pressure dependent DC magnetization studies on β-(BDA-TTP)2FeCl4 compound revealed that the AFM ordering persist well above Pc. In spite of similarity of phase diagram between M=Fe and M=Ga compounds, magnetoresistance results show distinct behaviors, which indicates the magnetic interaction with the conduction electrons are still effective. The comparison between X=Cl and X=Br compounds suggests the anion-size effect rather than the existence of localized magnetic moments plays more important role in determining the ground state.

  2. Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

    2016-03-01

    Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.

  3. A Novel Ternary CoFe2O4/CuO/CoFe2O4 as a Giant Magnetoresistance Sensor

    Directory of Open Access Journals (Sweden)

    Ramli

    2016-12-01

    Full Text Available This paper reports the results of a study relating to the synthesis of a novel ternary CoFe2O4/CuO/CoFe2O4 thin film as a giant magnetoresistance (GMR sensor. The CoFe2O4/CuO/CoFe2O4 thin film was prepared onto silicon substrate via DC magnetron sputtering with the targets facing each other. X-ray diffraction was used to determine the structure of the thin film and a 4-point method was used to measure the MR ratio. The GMR ratio is highly dependent on the ferrimagnetic (CoFe2O4 and nonmagnetic (CuO layer thickness. The maximum GMR ratio at room temperature obtained in the CoFe2O4/CuO/CoFe2O4 thin film was 70% when the CoFe2O4 and the CuO layer had a thickness of 62.5 nm and 14.4 nm respectively.

  4. What is the best bonding model of the (σ-H-BR) species bound to a transition metal? Bonding analysis in complexes [(H)2Cl(PMe3)2M(σ-H-BR)] (M = Fe, Ru, Os).

    Science.gov (United States)

    Pandey, Krishna K

    2012-03-21

    Density Functional Theory calculations have been performed for the σ-hydroboryl complexes of iron, ruthenium and osmium [(H)(2)Cl(PMe(3))(2)M(σ-H-BR)] (M = Fe, Ru, Os; R = OMe, NMe(2), Ph) at the BP86/TZ2P/ZORA level of theory in order to understand the interactions between metal and HBR ligands. The calculated geometries of the complexes [(H)(2)Cl(PMe(3))(2)Ru(HBNMe(2))], [(H)(2)Cl(PMe(3))(2)Os(HBR)] (R = OMe, NMe(2)) are in excellent agreement with structurally characterized complexes [(H)(2)Cl(P(i)Pr(3))(2)Os(σ-H-BNMe(2))], [(H)(2)Cl(P(i)Pr(3))(2)Os{σ-H-BOCH(2)CH(2)OB(O(2)CH(2)CH(2))}] and [(H)(2)Cl(P(i)Pr(3))(2)Os(σ-H-BNMe(2))]. The longer calculated M-B bond distance in complex [(H)(2)Cl(PMe(3))(2)M(σ-H-BNMe(2))] are due to greater B-N π bonding and as a result, a weaker M-B π-back-bonding. The B-H2 bond distances reveal that (i) iron complexes contain bis(σ-borane) ligand, (ii) ruthenium complexes contain (σ-H-BR) ligands with a stretched B-H2 bond, and (iii) osmium complexes contain hydride (H2) and (σ-H-BR) ligands. The H-BR ligands in osmium complexes are a better trans-directing ligand than the Cl ligand. Values of interaction energy, electrostatic interaction, orbital interaction, and bond dissociation energy for interactions between ionic fragments are very large and may not be consistent with M-(σ-H-BR) bonding. The EDA as well as NBO and AIM analysis suggest that the best bonding model for the M-σ-H-BR interactions in the complexes [(H)(2)Cl(PMe(3))(2)M(σ-H-BR)] is the interaction between neutral fragments [(H)(2)Cl(PMe(3))(2)M] and [σ-H-BR]. This becomes evident from the calculated values for the orbital interactions. The electron configuration of the fragments which is shown for C in Fig. 1 experiences the smallest change upon the M-σ-H-BR bond formation. Since model C also requires the least amount of electronic excitation and geometry changes of all models given by the ΔE(prep) values, it is clearly the most appropriate choice of

  5. Experiment and simulation on the thermal instability of a heavily deformed Cu-Fe composite

    International Nuclear Information System (INIS)

    Qu Lei; Wang Engang; Zuo Xiaowei; Zhang Lin; He Jicheng

    2011-01-01

    Research highlights: → Fe fibers undergo thermal instability at temperature above 600 deg. C. → Longitudinal boundary splitting is the dominant instability process. → Instability of cylindrical fibers is controlled by breakup, growth and coarsening. → Breakup times can be predicted by Rayleigh perturbation model accurately. → The increase of fiber diameters is due to the coarsening and growth. - Abstract: The thermal instability of the Fe fibers in the heavily deformed Cu-12.8 wt.%Fe composites is investigated experimentally and numerically. The fiber evolution is characterized by a field emission scanning electron microscopy (FESEM). The results show that the dominant instability of the Fe fibers is the longitudinal boundary splitting which is determined by the greater cross sectional aspect ratio (width/thickness, w/t) and the larger ratio of boundary to interfacial energy (γ B /γ S ). The longitudinal boundary splitting makes the ribbon-like Fe fibers evolve into a series of cylindrical fibers. Then the cylindrical Fe fibers undergo the instability process in terms of the breakup, growth and coarsening concurrently. The breakup times are accurately predicted by the Rayleigh perturbation model. The growth process primarily contributes to the higher increasing rate of the fiber radius during isothermal annealing at 700 deg. C than that calculated by the coarsening theory developed for cylindrical fibers, since the Cu-matrix of composites is highly supersaturated after casting/cold-working process.

  6. Vibrational spectroscopic and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and the complexes Co2L2Cl4, Cu2L2Cl4 and Cu2L2Br2

    International Nuclear Information System (INIS)

    Nemcsok, Denes; Kovacs, Attila; Szecsenyi, Katalin Meszaros; Leovac, Vukadin M.

    2006-01-01

    In the present paper we report a joint experimental and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and its complexes Co 2 L 2 Cl 4 , Cu 2 L 2 Cl 4 and Cu 2 L 2 Br 2 . DFT computations were used to model the structural and bonding properties of the title compounds as well as to derive a reliable force field for the normal coordinate analysis of L. The computations indicated the importance of hydrogen bonding interactions in stabilising the global minimum structures on the potential energy surfaces. In contrast to the S-bridged binuclear Cu 2 L 2 Br 2 complex found in the crystal, our computations predicted the formation of (CuLBr) 2 dimers in the isolated state stabilized by very strong (53 kJ/mol) N-H...Br hydrogen bonding interactions. On the basis of FT-IR and FT-Raman experiments and the DFT-derived scaled quantum mechanical force field we carried out a complete normal coordinate analysis of L. The FT-IR spectra of the three complexes were interpreted using the present assignment of L, literature data and computed results

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

    International Nuclear Information System (INIS)

    Ni Junjie; Ma Tianyu; Yan Mi

    2011-01-01

    The microstructural and magnetic properties of Al 100-x Cu 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 100x Cu x exceeds to 25 at%, the (Pr, Nd)Cu and CuAl 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) 2 Fe 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 i H c due to the decreases of exchange coupling between the (Pr, Nd) 2 Fe 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 2 forms in grain boundaries with Cu content increase. → (Pr,Nd)Cu phases optimize microstructure and increase magnetic properties.

  8. Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

    International Nuclear Information System (INIS)

    Wirth, B D; Asoka-Kumar, P; Howell, R H; Odette, G R; Sterne, P A

    2001-01-01

    Radiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characterization of irradiated and thermally aged Fe-Cu and Fe-Cu-Mn alloys. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of CRPs and VSCs in both alloys. The CRPs are coarser in the Fe-Cu alloy and the number densities of CRP and VSC increase with the addition of Mn. The PAS involved measuring both the positron lifetimes and the Doppler broadened annihilation spectra in the high momentum region to provide elemental sensitivity at the annihilation site. The spectra in Fe-Cu-Mn specimens thermally aged to peak hardness at 450 C and irradiated at 288 C are nearly identical to elemental Cu. Positron lifetime and spectrum measurements in Fe-Cu specimens irradiated at 288 C clearly show the existence of long lifetime (∼500 ps) open volume defects, which also contain Cu. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of CRPs and VSCs and tend to discount high Fe concentrations in the CRPs

  9. Atomic simulations for configurations and solid-liquid interface of Li-Fe and Li-Cu icosahedra

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jianyu, E-mail: hnieyjy@aliyun.com [Hunan Institute of Engineering (China); Hu, Wangyu [Hunan University, College of Materials Science and Engineering (China); Dai, Xiongying [Hunan Institute of Engineering, College of Science (China)

    2017-04-15

    The melting point of Li is lower than that of Fe (or Cu); thus, solid-liquid interfaces can be easily formed on Li-Fe and Li-Cu nanoalloys. In this work, the configurations and solid-liquid interfaces of Li-Fe and Li-Cu icosahedra are studied using Monte Carlo and molecular dynamics methods. The atomic interactions are described by the analytic embedded-atom method. The dependence of composition, temperature, and nanoparticle size on the configurations and thermal stabilities of nanoalloys is discussed. The behavior of the Li-Fe and Li-Cu nanoalloys in segregation, configuration, and thermal stability is investigated. A different behavior of surface segregation of Li atoms is observed for the two types of nanoalloys. The interface between the Li and Fe atoms is clear. Mixing of Li with Cu at larger nanoparticle sizes is found because of low heat of formation in the system. The configurations of the Li-Fe and Li-Cu nanoalloys are related to the competition between surface segregation and alloying. The thermal stability of Li in the two types of nanoalloys is enhanced by the support of the Fe (or Cu) solid substrate.

  10. 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.

  11. Glass forming ability of the Fe-Zr-Cu system studied by thermodynamic calculation and ion beam mixing

    International Nuclear Information System (INIS)

    Wang, T.L.; Liu, B.X.

    2009-01-01

    The glass forming ability/range (GFA/GFR) of the Fe-Zr-Cu system was studied by thermodynamic calculation based on Miedema's model and Alonso's method. It is found that when the atomic concentration of Zr is between 34% and 56%, no matter what the atomic concentrations of Fe and Cu are, amorphous phase could be obtained, thus the atomic mismatch playing a dominating role in influencing the GFA. While the atomic concentration of Zr is out of the above range, the GFA is highly influenced by the immiscibility between Fe and Cu. Experimentally, ion beam mixing was carried out to synthesize amorphous alloys in the Fe-Zr-Cu system. It turned out that in the samples with overall compositions of Fe 26 Zr 36 Cu 38 , Fe 52 Zr 27 Cu 21 and Fe 21 Zr 60 Cu 19 , which are located in or at the edge of the calculated GFR, amorphous phases were indeed obtained, whereas no amorphous phase was obtained if the overall compositions were located outside of the predicted region favoring for amorphous alloy formation, showing a good agreement between the experimental results and the thermodynamic calculation.

  12. Nd-Fe-B/Sm-M/Nd-M (M = Fe, Co, Ti, Cu, Zr) hybrid magnets with improved thermal stability

    Science.gov (United States)

    Grigoras, M.; Lostun, M.; Urse, M.; Borza, F.; Chiriac, H.; Lupu, N.

    2018-02-01

    Hybrid magnets of Nd12Fe82B6(2:14:1-phase)/Nd9.4Fe59Co25.3Ti6.3(3:29-phase) and Nd12Fe82B6/Sm11.1Co65.8Fe8.9Cu10.7Zr3.5(2:17-phase) with different weight ratio have been prepared by spark plasma sintering pressing technique from ball-milled powders obtained from melt-spun ribbons. Influence of the ratio between the two phases on the magnetic properties and thermal stability of the hybrid magnets was studied. It has been found that the ratio has a remarkable influence, especially on the thermal stability of the bulk magnets. However, the magnetic properties of such type of hybrid magnets result not only from the type and ratio of components but also from the interaction between them. It was found that in NdFeB/3:29 hybrid magnets with 15% content of 3:29-phase, the temperature coefficients of remanence (α) and of coercivity (β) are improved from -0.095 to -0.082 (%/°C) and from -0.57 to -0.47 (%/°C), respectively, as compared to the Nd2Fe14B single-phase counterpart. While for the NdFeB/2:17 hybrid magnets the content of 2:17-phase is not significantly influencing the temperature coefficient of induction (α), the temperature coefficient of °C (β) increases up to -0.41 (%/°C) for 10% content of 2:17-phase. The increase in the reversible temperature coefficients of hybrid magnets indicate a remarkable improvement of their thermal stability.

  13. Doping effects of Fe ion on magnetic anisotropy of YBa2Cu3Oy

    International Nuclear Information System (INIS)

    Ugawa, T.; Horii, S.; Maeda, T.; Haruta, M.; Shimoyama, J.

    2013-01-01

    Highlights: •We clarified orientation effects of Fe-doped Y123 in modulated rotating fields. •Y123 showed two different hard magnetic axes due to twin microstructures. •The two hard magnetic axes in Fe-doped Y123 were [1 0 0] and [1 1 0] directions. •Magnetic anisotropy of the [1 1 0] grain was higher than that of the [1 0 0] grain. -- Abstract: We report magnetic alignment of YBa 2 (Cu 1−x Fe x ) 3 O y (Fe-doped Y123, x = 0–0.1) powders under modulated rotation magnetic fields (MRFs) and roles of Fe ion as a determination factor of magnetic anisotropy in Y123. The Fe-free and Fe-doped Y123 powder samples aligned in the MRF of 10 T showed two different orientation types of the hard axis in Y123 grains. From an X-ray rocking curve measurement for the magnetically aligned powder samples of the Fe-doped Y123, inplane magnetic anisotropy for Y123 grains with the hard axis parallel to the [1 1 0] direction was found to be higher than that for Y123 grains with the hard axis parallel to the [0 1 0] direction

  14. Antifriction coating of Cu-Fe-Al-Pb system for plain bearings

    Science.gov (United States)

    Kotenkov, Pavel; Kontsevoi, Yurii; Mejlakh, Anna; Pastukhov, Eduard; Shubin, Alexey; Goyda, Eduard; Sipatov, Ivan

    2017-09-01

    Aluminium, copper and their compounds are used in common as basis for antifriction coatings of plain bearings. Antifriction testing of plain bearings (based on Al and Cu) made by leading automotive manufacturers from Germany, Japan, USA, United Kingdom and Russia were carried out to make judicious selection of basis for development of new antifriction material. Testing was carried out using friction machine. It was defined that materials based on Cu provide better durability and robustness of plain bearings in comparison with Al based ones. The new antifriction composite coatings based on copper were developed taking into account the requirements specified for plain bearings of internal-combustion engine. Pilot samples of plain bearings with antifriction coatings of Cu-Fe-Al-Pb system were produced. The antifriction composite having Cu-5Fe-5Al5Fe2-10Pb (mass %) composition has demonstrated low friction factor and high wear-resistance. Metallographic analysis of pilot samples was carried out by means of optical and scanning electron microscopy.

  15. Static and dynamic magnetic properties of two synthetic francisites Cu3La(SeO3)2O2X (X = Br and Cl)

    Science.gov (United States)

    Markina, M. M.; Zakharov, K. V.; Zvereva, E. A.; Denisov, R. S.; Berdonosov, P. S.; Dolgikh, V. A.; Kuznetsova, E. S.; Olenev, A. V.; Vasiliev, A. N.

    2017-04-01

    The formation of long-range magnetic order at low temperatures was established in francisite—type compounds Cu3La(SeO3)2O2X (X = Br and Cl) through measurements of magnetic susceptibility, magnetization, specific heat and X-band electron spin resonance. The significantly enhanced critical index p = 1.0 ± 0.1 in Cu3La(SeO3)2Br and p = 0.8 ± 0.1 in Cu3La(SeO3)2Cl in the temperature dependence of the width of ESR signal evidence the reduced dimensionality of the kagome-type francisite's magnetic subsystem. Under action of external magnetic field, the presumably non-collinear six-sublattices antiferromagnetic structure of these compounds experiences the first-order metamagnetic transformation. The B- T magnetic phase diagrams were established from the positions of singularities in temperature and field dependences of thermodynamic properties. Contrary to pristine mineral Cu3Bi(SeO3)2Cl, no signature of structural phase transition was detected.

  16. Ultrafast magnon generation in an Fe film on Cu(100).

    Science.gov (United States)

    Schmidt, A B; Pickel, M; Donath, M; Buczek, P; Ernst, A; Zhukov, V P; Echenique, P M; Sandratskii, L M; Chulkov, E V; Weinelt, M

    2010-11-05

    We report on a combined experimental and theoretical study of the spin-dependent relaxation processes in the electron system of an iron film on Cu(100). Spin-, time-, energy- and angle-resolved two-photon photoemission shows a strong characteristic dependence of the lifetime of photoexcited electrons on their spin and energy. Ab initio calculations as well as a many-body treatment corroborate that the observed properties are determined by relaxation processes involving magnon emission. Thereby we demonstrate that magnon emission by hot electrons occurs on the femtosecond time scale and thus provides a significant source of ultrafast spin-flip processes. Furthermore, engineering of the magnon spectrum paves the way for tuning the dynamic properties of magnetic materials.

  17. Modulation of Jahn-Teller effect on magnetization and spontaneous electric polarization of CuFeO2

    Science.gov (United States)

    Xiao, Guiling; Xia, Zhengcai; Wei, Meng; Huang, Sha; Shi, Liran; Zhang, Xiaoxing; Wu, Huan; Yang, Feng; Song, Yujie; Ouyang, Zhongwen

    2018-03-01

    CuFe0.99Mn0.01O2 and CuFe0.99Co0.01O2 single crystal samples are grown by a floating zone technique and their magnetization and spontaneous electric polarization have been investigated. Similarly with pure CuFeO2, an obviously anisotropic magnetization and spontaneous electric polarization were observed in the both doped samples, and their phase transition critical fields and temperatures are directly doping ion dependent. Considering the different d-shell configuration and ionic size between Mn3+, Co3+ and Fe3+ ions, in which the Mn3+ ion with Jahn-Teller (J-T) effect has different distortion on the geometry frustration from both of Fe3+ and Co3+ ion. Since for Mn3+ ion, the orbital splitting results from the low-symmetry J-T distortion in a crystal-field environment leads to a distorted MnO6 octahedron, which different from undistorted FeO6 and CoO6 octahedrons. The strain between distorted and undistorted octahedrons produces different effects on the spin reorientation transition and spontaneous electric polarization. Although the pure CuFeO2 has a very strong and robust frustration, the presence of the strain due to the random distribution of distorted MnO6 octahedron and undistorted CoO6 (FeO6) octahedrons leads to its spin reorientation transitions and spontaneous electric polarization different from CuFeO2.

  18. Investigation of the solubility and diffusion of Fe atoms in Cu at high temperature using molten salt electrochemistry

    International Nuclear Information System (INIS)

    Wenzl, H.; Sorajic, V.; Bischof, B.

    1977-01-01

    The electrochemical cell CuFesub(n)/KF, LiF, FeF 2 (molten solution)/Fe was used between 800 and 1,000 0 C to produce CuFesub(n) alloys of various copper rich compositions n by electrochemically controlled diffusion. From measurements of cell voltage and current we determined composition, bulk diffusion coefficient D, and atomic solubility limit x 0 of Fe in Cu. The numerical values at the temperature of 950 0 C are D = 0.9 x 10 -9 cm 2 /sec, x 0 = 1.2 at%. (orig.) [de

  19. Magnetism of CuCl{sub 2}·2D{sub 2}O and CuCl{sub 2}·2H{sub 2}O, and of CuBr{sub 2}·6H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

    2017-07-15

    Highlights: • CuCl{sub 2}·2D{sub 2}O is examined magnetically and compared with CuCl{sub 2}·2H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 2}·6H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 2}·6H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 2}·6H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 2}·2D{sub 2}O are studied and compared with those of CuCl{sub 2}·2H{sub 2}O. New CuBr{sub 2}·6H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 2}·6H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

  20. Thermodynamic properties of Al-Mn, Al-Cu, and Al-Fe-Cu melts and their relations to liquid and quasicrystal structure

    International Nuclear Information System (INIS)

    Zaitsev, A I; Zaitseva, N E; Shimko, R Yu; Arutyunyan, N A; Dunaev, S F; Kraposhin, V S; Lam, Ha Thanh

    2008-01-01

    Thermodynamic properties of molten Al-Mn, Al-Cu and Al-Fe-Cu alloys in a wide temperature range of 1123-1878 K and the whole range of concentrations have been studied using the integral effusion method and Knudsen mass spectrometry. Thermodynamic functions of melts were described by the associated solution model. The possibility of icosahedral quasicrystal (i-QC) precipitation from liquid Al-Mn and Al-Cu-Fe alloys was found to be a consequence of the existence in liquid associates (clusters). A geometric model is suggested for the structure of associates in liquid

  1. Study on the process of sintering matrix metallic Fe-Cu-25%Nb and Fe-Cu-25%Co during hot pressing

    International Nuclear Information System (INIS)

    Batista, A.C.; Oliveira, H.C.P.; Souza, M.H.; Assis, P.S.

    2016-01-01

    The sintering process promotes densification and the evolution of the microstructure of the material, with consequent significant increase in hardness and mechanical strength. However, few studies show the influence of pressure and temperature during sintering by hot pressing. In this sense, this work aims to evaluate the microstructural changes and properties with the variation of pressure and temperature and the type suffered by sintering metal powders during sintering by hot pressing. For this, two samples were studied by changing the sintering parameters: 25% Fe-50% Cu-25% Nb and 25% Fe-50% Cu-25% Co. Samples were analyzed by SEM / EDS in order to check the morphology and the presence of pores, as well as the interaction between the metallic constituents of each sample by the EDS analysis in line. They also determined the relative density, porosity and Vickers hardness (HV5). At the end of the study it was concluded that niobium alloy composite element by sintering activated suffered together with the liquid phase sintering. For cobalt alloys were observed by liquid phase sintering. The increase in the severity of the sintering conditions (temperature and pressure) led to an improvement in physical and mechanical properties of the alloys, which indicates that these parameters are directly related to the mechanisms of diffusion in the sintering process, improving the properties and diffusivity between elements. (author)

  2. Influence of surface topography on RBS measurements: case studies of (Cu/Fe/Pd) multilayers and FePdCu alloys nanopatterned by self-assembly

    Science.gov (United States)

    Krupinski, M.; Perzanowski, M.; Zabila, Y.; Zarzycki, A.; Marszałek, M.

    2017-03-01

    In this paper the influence of surface topography on Rutherford backscattering spectrometry (RBS) is discussed. (Cu/Fe/Pd) multilayers with total thickness of about 10 nm were deposited by physical vapor deposition on self-organized array of SiO2 nanoparticles with the size of 50 nm and 100 nm. As a reference, the multilayered systems were also prepared on flat substrates under the same conditions. After the deposition, morphology of the systems was studied by scanning electron microscopy (SEM), while chemical analysis was performed using Rutherford backscattering spectrometry. It was found that the RBS spectra and determined compositions for flat and patterned multilayers differ. The difference is discussed by taking into account the effect of additional inelastic scattering and energy straggling occurring due to developed topography of patterned systems. Then, the multilayers were annealed in 600 °C in order to obtain FePdCu alloy. The phenomenon of solid-state dewetting resulted in the formation of isolated alloy islands on the top of SiO2 nanoparticles. The SEM and RBS analysis were repeated showing correlation between the size distribution of obtained alloy islands and broadening of peaks appearing in RBS spectra. Invited talk at 8th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN2016), 8-12 November 2016, Ha Long City, Vietnam.

  3. Mechanistic Effects of Water on the Fe-Catalyzed Hydrodeoxygenation of Phenol. The Role of Brønsted Acid Sites

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, Alyssa J. R. [The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, ∥Department of Physics; Institute for Integrated Catalysis and §Fundamental and; Wang, Yong [The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, ∥Department of Physics; Institute for Integrated Catalysis and §Fundamental and; Mei, Donghai [The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, ∥Department of Physics; Institute for Integrated Catalysis and §Fundamental and; McEwen, Jean-Sabin [The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, ∥Department of Physics; Institute for Integrated Catalysis and §Fundamental and

    2018-01-30

    A mechanistic understanding of the roles of water is essential for developing highly active and selective catalysts for hydrodeoxygenation (HDO) reactions since water is ubiquitous in such reaction systems. Here, we present a study for phenol HDO on Fe catalysts using density functional theory which examines the effect of water on three elementary pathways for phenol HDO using an explicit solvation model. The presence of water is found to significantly decrease activation barriers required by hydrogenation reactions via two pathways. First, the proton transfer in the hydrogen bonding network of the liquid water phase is nearly barrierless, which significantly promotes the direct through space tautomerization of phenol. Second, due to the high degree of oxophilicity on Fe, liquid water molecules are found to be easily dissociated into surface hydroxyl groups that can act as Brønsted acid sites. These sites dramatically promote hydrogenation reactions on the Fe surface. As a result, the hydrogen assisted dehydroxylation becomes the dominant phenol HDO pathway. This work provides new fundamental insights into aqueous phase HDO of biomass-derived oxygenates over Fe-based catalysts; e.g., the activity of Fe-based catalysts can be optimized by tuning the surface coverage of Brønsted acid sites via surface doping.

  4. Amorphous Fe72Cu1V4Si15B8 ribbon as magneto-impedance sensing element

    Directory of Open Access Journals (Sweden)

    Surla Radoslav

    2016-01-01

    Full Text Available Мagneto-impedance (MI effect in the Fe72Cu1V4Si15B8 amorphous ribbon obtained by melt spinning method has been studied. The aim of study was the characterisation of this ribbon in as-cast state in terms of its application as a MI sensor. The experiments on MI elements were performed in the frequency range from 30 kHz to 300 MHz and maximum external magnetic field up to 28.6 kA/m. Maximum observed MI-ratio (ΔZ = Z(0 - Z(Hmax, Hmax = 28.6 kA/m has amounted to ΔZ/Z(Hmax = 173% at a frequency of 20.46 MHz. The MI curve measured up to 20 MHz shows some shoulder indicating the growth of rotational contribution of magnetization that appears above the domain wall relaxation frequency. The MI profile at frequencies higher than 30 MHz, exhibits a clear peak positioned at transverse anisotropy field Hk, suggesting domination of rotation magnetization in transverse permeability. The linearity in the range up to 5 kA/m with sensitivity of about 11 %/kA/m was observed. [Projekat Ministarstva nauke Republike Srbije, br. OI 172057

  5. 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.

  6. Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

    DEFF Research Database (Denmark)

    Bjergbakke, Erling; Hart, E.J.

    1971-01-01

    value diminishes slightly and is displaced toward higher ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratios with increasing acidity. The perchlorate system differs from the sulfate only at high ${\\rm Cu}({\\rm ClO}_{4})/{\\rm Fe}({\\rm ClO}_{4})_{2}$ ratios where $G({\\rm O}_{2})$ rises to 0.10. The O2 yield of 0.......02 is not derived from "spur" HO2, OH, H2 O2 or O2, although the increase in $G({\\rm O}_{2})$ above this level in the perchlorate system is attributed to H2 O2. "Spur" O atoms are postulated as the source of O2 with the yield, $G({\\rm O}_{2})$ = 0.02....

  7. Heavy metal (Cu, Cr, Zn, and Fe) concentration on coralreef in panjang island coastal, Jepara

    International Nuclear Information System (INIS)

    Heni Susiati; Yarianto SBS; Ali Arman L; Yulizon Menri

    2008-01-01

    Observation on the accumulation of Cu, Cr, Zn, and Fe heavy metals in coral tissue were carried out in Panjang island, Jepara by NAA method. The purpose of this research is to determine the concentration of heavy metals on coral reef tissue in order to update environmental data to support site licensing and Environmental Impact Assessment (EIA) of Nuclear Power Plants (NPP). The result indicated that the concentration of Zn is 1,78 - 42,34 ppm, Cu is undetected - 0,41 ppm, Cr is 0,03 - 0,35 ppm and Fe is 5,25 - 30,56 ppm. The data shows that the accumulation of heavy metals in the coral reef tissue is higher than environmental threshold value, especially for marine biota life referring to the Environmental Ministry Decree Number 51 year 2004. (author)

  8. The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

    Directory of Open Access Journals (Sweden)

    Dilermando Nagle Travessa

    2012-10-01

    Full Text Available In order to obtain quasicrystalline (QC phase by mechanical alloying (MA in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. % were produced by high energy ball milling (HEBM. A very high energy type mill (spex and short milling times (up to 5 hours were employed. The resulting powders were characterized by X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.

  9. Correlation between the oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

    Science.gov (United States)

    Park, Sang-Yoon; Lee, Myung-Ho; Jeong, Yong-Hwan; Jung, Youn-Ho

    2004-12-01

    The correlation between the oxide impedance and corrosion behavior of two series of Zr-Nb-Sn-Fe-Cu alloys was evaluated. Corrosion tests were performed in a 70 ppm LiOH aqueous solution at 360°C for 300 days. The results of the corrosion tests revealed that the corrosion behavior of the alloys depended on the Nb and Sn content. The impedance characteristics for the pre- and post-transition oxide layers formed on the surface of the alloys were investigated in sulfuric acid at room temperature. From the results, a pertinent equivalent circuit model was preferably established, explaining the properties of double oxide layers. The impedance of the oxide layers correlated with the corrosion behavior; better corrosion resistance always showed higher electric resistance for the inner layers. It is thus concluded that a pertinent equivalent circuit model would be useful for evaluating the long-term corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys.

  10. Superconductivity and spin fluctuations in M-Zr metallic glasses (M = Cu, Ni, Co, and Fe)

    International Nuclear Information System (INIS)

    Altounian, Z.; Strom-Olsen, J.O.

    1983-01-01

    The superconducting transition temperature, upper critical field, and magnetic susceptibility have been measured in four binary metallic glass systems: Cu-Zr, Ni-Zr, Co-Zr, and Fe-Zr. For each alloy system, a full and continuous range of Zr-rich compositions accessible by melt spinning has been examined. For Cu-Zr, the range is 0.75>x>0.30; for Ni-Zr, 0.80>x>0.30; for Co-Zr, 0.80>x>0.48, and for Fe-Zr, 0.80>x>0.55 (x being the concentration of Zr in at. %). The results show clearly the influence of spin fluctuations in reducing the superconducting transition temperature. The data have been successfully analyzed using a modified form of the McMillan equation together with expressions for the Stoner enhanced magnetic susceptibility and the Ginsburg-Landau-Abrikosov-Gor'kov expression for the upper critical field

  11. Friction and wear properties of Cu and Fe-based P/M bearing materials

    International Nuclear Information System (INIS)

    Tufekci, Kenan; Kurbanoglu, Cahit; Durak, Ertugrul; Tunay, R. Fatih

    2006-01-01

    The performances of porous bearings under different operating conditions were experimentally investigated in this study. Material groups studied are 90%Cu + 10%Sn bronze and 1%C + % balance Fe iron-based self-lubricating P/M bearings at constant (85%) density. In the experiments, the variation of the coefficient of friction and wear ratio of those two different group materials for different sliding speeds, loads, and temperatures were investigated. As a result, the variation of the friction coefficient - temperature for both constant load, and constant sliding speed, friction coefficient - average bearing pressure, PV - wear loss and temperature-wear loss curves were plotted and compared with each other for two materials, separately. The test results showed that Cu-based bearings have better friction and wear properties than Fe-based bearings

  12. Atomic structure of Fe thin-films on Cu(0 0 1) studied with stereoscopic photography

    International Nuclear Information System (INIS)

    Hattori, Azusa N.; Fujikado, M.; Uchida, T.; Okamoto, S.; Fukumoto, K.; Guo, F.Z.; Matsui, F.; Nakatani, K.; Matsushita, T.; Hattori, K.; Daimon, H.

    2004-01-01

    The complex magnetic properties of Fe films epitaxially grown on Cu(0 0 1) have been discussed in relation to their atomic structure. We have studied the Fe films on Cu(0 0 1) by a new direct method for three-dimensional (3D) atomic structure analysis, so-called 'stereoscopic photography'. The forward-focusing peaks in the photoelectron angular distribution pattern excited by the circularly polarized light rotate around the light axis in either clockwise or counterclockwise direction depending on the light helicity. By using a display-type spherical mirror analyzer for this phenomenon, we can obtain stereoscopic photographs of atomic structure. The photographs revealed that the iron structure changes from bcc to fcc and almost bcc structure with increasing iron film thickness

  13. Safe-by-Design CuO Nanoparticles via Fe-Doping, Cu-O Bond Length Variation, and Biological Assessment in Cells and Zebrafish Embryos.

    Science.gov (United States)

    Naatz, Hendrik; Lin, Sijie; Li, Ruibin; Jiang, Wen; Ji, Zhaoxia; Chang, Chong Hyun; Köser, Jan; Thöming, Jorg; Xia, Tian; Nel, Andre E; Mädler, Lutz; Pokhrel, Suman

    2017-01-24

    The safe implementation of nanotechnology requires nanomaterial hazard assessment in accordance with the material physicochemical properties that trigger the injury response at the nano/bio interface. Since CuO nanoparticles (NPs) are widely used industrially and their dissolution properties play a major role in hazard potential, we hypothesized that tighter bonding of Cu to Fe by particle doping could constitute a safer-by-design approach through decreased dissolution. Accordingly, we designed a combinatorial library in which CuO was doped with 1-10% Fe in a flame spray pyrolysis reactor. The morphology and structural properties were determined by XRD, BET, Raman spectroscopy, HRTEM, EFTEM, and EELS, which demonstrated a significant reduction in the apical Cu-O bond length while simultaneously increasing the planar bond length (Jahn-Teller distortion). Hazard screening was performed in tissue culture cell lines and zebrafish embryos to discern the change in the hazardous effects of doped vs nondoped particles. This demonstrated that with increased levels of doping there was a progressive decrease in cytotoxicity in BEAS-2B and THP-1 cells, as well as an incremental decrease in the rate of hatching interference in zebrafish embryos. The dissolution profiles were determined and the surface reactions taking place in Holtfreter's solution were validated using cyclic voltammetry measurements to demonstrate that the Cu + /Cu 2+ and Fe 2+ /Fe 3+ redox species play a major role in the dissolution process of pure and Fe-doped CuO. Altogether, a safe-by-design strategy was implemented for the toxic CuO particles via Fe doping and has been demonstrated for their safe use in the environment.

  14. Antifungal activity of magnetically separable Fe3O4/ZnO/AgBr nanocomposites prepared by a facile microwave-assisted method

    Directory of Open Access Journals (Sweden)

    Abolghasem Hoseinzadeh

    2016-08-01

    Full Text Available In the present work, magnetically separable Fe3O4/ZnO/AgBr nanocomposites with different weight ratios of Fe3O4 to ZnO/AgBr were prepared by a facile microwave-assisted method. The resultant samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive analysis of X-rays (EDX, and vibrating sample magnetometery (VSM. Antifungal activity of the as-prepared samples was evaluated against Fusarium graminearum and Fusarium oxysporum as two phytopathogenic fungi. Among the nanocomposites, the sample with 1:8 weight ratio of Fe3O4 to ZnO/AgBr was selected as the best nanocomposite. This nanocomposite inactivates Fusarium graminearum and Fusarium oxysporum at 120 and 60 min, respectively. Moreover, it was observed that the microwave irradiation time has considerable influence on the antifungal activity and the sample prepared by irradiation for 10 min showed the best activity. Moreover, the nanocomposite without any thermal treatment displayed the superior activity.

  15. 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...

  16. Sequestration of Radionuclides and Heavy Metals by Hydroxyapatite Doped with Fe, Cu and Sn

    International Nuclear Information System (INIS)

    K.B. Helean; R.C. Moore

    2005-01-01

    Apatite, Ca 5 (PO 4 ) 3 (F,OH,Cl) (P6 3 /m, Z=2), is the most abundant phosphate mineral on Earth. The end-member hydroxyapatite, Ca 5 (PO 4 ) 3 OH (P2 1 /b), is the primary mineral component in bones and teeth and tends to scavenge and sequester heavy metals in the human body. Hydroxyapatite has also been shown to be effective at sequestering radionuclides and heavy metals in certain natural systems (Dybowska et al., 2004). Hydroxyapatite has been the focus of many laboratory studies and is utilized for environmental remediation of contaminated sites (Moore et al., 2002). The crystal structure of apatite tolerates a great deal of distortion caused by extensive chemical substitutions. Metal cations (e.g. REE, actinides, K, Na, Mn, Ni, Cu, Co, Zn, Sr, Ba, Pb, Cd, Fe) substitute for Ca, and oxyanions (e.g. AsO 4 3- , SO 4 2- , CO 3 2- , SiO 4 4- , CrO 4 2- ) replace PO 4 3- through a series of coupled substitutions that preserve electroneutrality. Owing to the ability of apatite to incorporate ''impurities'' (including actinides) gives rise to its proposed use as a waste form for radionuclides. Recent work at Sandia National Laboratory demonstrated that hydroxyapatite has a strong affinity for U, Pu, Np, Sr and Tc reduced from pertechnetate (TcO 4 - ) by SnCl 2 (Moore et al., 2002). Based on these earlier promising results, an investigation was initiated into the use of apatite-type materials doped with aliovalent cations including Fe, Cu and Sn as Tc-scavengers. Synthetic Fe and Cu-doped hydroxyapatite samples were prepared by precipitation of Ca, from Ca-acetate, and P, from ammonium phosphate. The Fe and Cu were introduced as chlorides into the Ca-acetate solution. Stannous chloride was used as a reducing agent and was apparently incorporated into the crystal structures of the hydroxyapatite samples in small, as yet undetermined quantities

  17. THERMAL STABILITY OF Al-Cu-Fe QUASICRYSTALS PREPARED BY SHS METHOD

    OpenAIRE

    Pavel Novák; Alena Michalcová; Milena Voděrová; Ivo Marek; Dalibor Vojtěch

    2013-01-01

    Quasicrystal-containing materials are usually prepared by rapid solidification of the melt (e.g. by melt spinning) or mechanical alloying. In this work, the method using exothermic reactions between compressed metallic powders called SHS (Self-propagating High-temperature Synthesis) was tested. The microstructure and phase composition of the product was described in dependence on cooling regime from the reaction temperature. Thermal stability of prepared Al-Cu-Fe quasicrystals was studied by...

  18. Determination of Cu, Fe, Zn Elements in Soil, Root Tea Plants, Tea Leaves, and Tea Beverage

    International Nuclear Information System (INIS)

    Supriyanto; Zainul-Kamal

    2006-01-01

    One of the causes of land quality damage was due to the pollution of Cu, Fe, and Zn so that it could directly and also indirectly cause the occurrence of pollution of plants which is growing on it for example tea plant that has been used by society for making of tea beverage. The sampling of soil, root tea plants, tea leaves and tea beverage samples were done in June, 2005 at sub district of Keparakan, Temanggung, Central Java. The purpose of research was to determine the content of Cu, Fe and Zn in soil, root tea plants, tea leaves and tea beverage. The research was done by digesting the sample with nitric acid until the clear solution was obtained, then it was added by aquabidest until 10.0 ml. Determination of Cu, Fe and Zn content used AAS instrument. The average concentration of Cu Fe and Zn obtained in deep soil samples area 0.155 ± 0.005 ppm, 127.16 ± 2.65 ppm, and 0.68 ± 0.02 ppm respectively, in surface soil samples are 0.355 ± 0.025 ppm, 360.59 ± 13.17 ppm and 0.78 ± 0.01 ppm respectively, in root of tea plants samples area 0.241 ± 0.098 ppm, 13.16 ± 1.34 ppm and 2.64 ± 0.06 ppm respectively, in tea leaves are 0.211 ± 0.013 ppm, 3.35 ± 0.886 ppm, and 0.795 ± 0.016 ppm respectively and in tea beverage 0.142 ± 0.086 ppm, 6.11 ± 0.35 ppm and 0.66 ± 0.02 ppm respectively. (author)

  19. Fe3O4@HKUST-1 and Pd/Fe3O4@ HKUST-1 as magnetically recyclable catalysts prepared via conversion from a Cu-based ceramic

    OpenAIRE

    Toyao, Takashi; Styles, Mark J.; Yago, Tokuichiro; Sadiq, Muhammad M.; Ricco, Raffaele; Suzuki, Kiyonori; Horiuchi, Yu; Takahashi, Masahide; Matsuoka, Masaya; Falcaro, Paolo

    2017-01-01

    Nanocomposites obtained by integrating iron oxide magnetic nanoparticles (Fe3O4) into a metal-organic framework (HKUST-1 or Cu-3(BTC)(2), BTC = 1,3,5-benzenetricarboxylate) are synthesized through conversion from a composite of a Cu-based ceramic material and Fe3O4. In situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) measurements reveal that the presence of Fe3O4 leads to the fast conversion and synthesis of HKUST-1 with small particle sizes. The prepared MOF co...

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

    International Nuclear Information System (INIS)

    Cunha e Silva, R.M.; Almeida, E.; Valencia, E.P.E.; Nascimento Filho, V.F.

    2004-01-01

    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)

  1. Microwave-Assisted Synthesis of CuFe2O4 Nanoparticles and Starch-Based Magnetic Nanocomposites

    Directory of Open Access Journals (Sweden)

    Gh. Nabiyouni

    2013-06-01

    Full Text Available Magnetic CuFe2O4 nanoparticles were synthesized by a facile microwave-assisted reaction between Cu(NO32 and Fe(NO33. The magnetic nanoparticles were added to starch to make magnetic polymeric nanocomposite. The nanoparticles and nanocomposites were characterized using X-ray diffraction and scanning electron microscopy. The magnetic properties of the samples were investigated using an alternating gradient force magnetometer (AGFM. The copper ferrite nanoparticles exhibited ferromagnetic behavior at room temperature, with a saturation magnetization of 29emu/g and a coercivity of 136 Oe. The distribution of the CuFe2O4 nanoparticles into the polymeric matrixes decreases the coercivity (136 Oe to 66 Oe. The maximum coercivity of 82 Oe was found for 15% of CuFe2O4 distributed to the starch matrix.

  2. Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

    Science.gov (United States)

    Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

    2018-04-01

    This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity (H c > 10 kOe) can be achieved without any microstructural refinement.

  3. TRACE METAL CONTENT (Cu, Zn, Mn AND Fe) IN URTICA DIOICA L. AND PLANTAGO MAJOR L.

    Science.gov (United States)

    Krolak, Elzbieta; Raczuk, Jolanta; Borkowska, Lidia

    2016-11-01

    The aim of the study was to compare the contents of Cu, Zn, Mn and Fe in the washed and unwashed leaves and roots of two plant species: Urica dioica L. and Plantago major L., used in herbal medicine. These two herb species occur in the same environmental habitats, yet their morphological structure is different. The soil and plant samples for analyses were collected from an uncontaminated area in Eastern Poland. In each habitat location, the samples were taken from sandy soils with slightly acidic and neutral pH values. The obtained results showed that U. dioica and P. major accumulated similar amounts of trace metals, such as: Cu, Zn and Fe, in leaves, despite the differences in the morphological structure of their overground parts. The content of Mn in leaves U. dioica was about twice as much as in P. major. Also, no differences in the metal content were observed between washed and unwashed leaves of both species. However, in the same habitat conditions, a significantly higher content of Cu, Zn and Mn was found in the roots of P. major than U. dioica. The content of Fe in the roots was similar in both species. P. major and U. dioica may be a valuable source of microelements, if they are obtained from unpolluted habitats.

  4. Artificial intelligence applied to atomistic kinetic Monte Carlo simulations in Fe-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Djurabekova, F.G. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Domingos, R. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Cerchiara, G. [Department of Nuclear and Production Engineering, University of Pisa (Italy); Castin, N. [Catholic University of Louvain-la-Neuve (Belgium); Vincent, E. [LMPGM UMR-8517, University of Lille I, Villeneuve d' Ascq (France); Malerba, L. [Reactor Materials Research Unit, SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)]. E-mail: lmalerba@sckcen.be

    2007-02-15

    Vacancy migration energies as functions of the local atomic configuration (LAC) in Fe-Cu alloys have been systematically tabulated using an appropriate interatomic potential for the alloy of interest. Subsets of these tabulations have been used to train an artificial neural network (ANN) to predict all vacancy migration energies depending on the LAC. The error in the prediction of the ANN has been evaluated by a fuzzy logic system (FLS), allowing a feedback to be introduced for further training, to improve the ANN prediction. This artificial intelligence (AI) system is used to develop a novel approach to atomistic kinetic Monte Carlo (AKMC) simulations, aimed at providing a better description of the kinetic path followed by the system through diffusion of solute atoms in the alloy via vacancy mechanism. Fe-Cu has been chosen because of the importance of Cu precipitation in Fe in connection with the embrittlement of reactor pressure vessels of existing nuclear power plants. In this paper the method is described in some detail and the first results of its application are presented and briefly discussed.

  5. Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

    Science.gov (United States)

    Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

    2018-06-01

    This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.

  6. Artificial intelligence applied to atomistic kinetic Monte Carlo simulations in Fe-Cu alloys

    International Nuclear Information System (INIS)

    Djurabekova, F.G.; Domingos, R.; Cerchiara, G.; Castin, N.; Vincent, E.; Malerba, L.

    2007-01-01

    Vacancy migration energies as functions of the local atomic configuration (LAC) in Fe-Cu alloys have been systematically tabulated using an appropriate interatomic potential for the alloy of interest. Subsets of these tabulations have been used to train an artificial neural network (ANN) to predict all vacancy migration energies depending on the LAC. The error in the prediction of the ANN has been evaluated by a fuzzy logic system (FLS), allowing a feedback to be introduced for further training, to improve the ANN prediction. This artificial intelligence (AI) system is used to develop a novel approach to atomistic kinetic Monte Carlo (AKMC) simulations, aimed at providing a better description of the kinetic path followed by the system through diffusion of solute atoms in the alloy via vacancy mechanism. Fe-Cu has been chosen because of the importance of Cu precipitation in Fe in connection with the embrittlement of reactor pressure vessels of existing nuclear power plants. In this paper the method is described in some detail and the first results of its application are presented and briefly discussed

  7. Efficient Carbon-Based CsPbBr3 Inorganic Perovskite Solar Cells by Using Cu-Phthalocyanine as Hole Transport Material

    Science.gov (United States)

    Liu, Zhiyong; Sun, Bo; Liu, Xingyue; Han, Jinghui; Ye, Haibo; Shi, Tielin; Tang, Zirong; Liao, Guanglan

    2018-06-01

    Metal halide perovskite solar cells (PSCs) have attracted extensive research interest for next-generation solution-processed photovoltaic devices because of their high solar-to-electric power conversion efficiency (PCE) and low fabrication cost. Although the world's best PSC successfully achieves a considerable PCE of over 20% within a very limited timeframe after intensive efforts, the stability, high cost, and up-scaling of PSCs still remain issues. Recently, inorganic perovskite material, CsPbBr3, is emerging as a promising photo-sensitizer with excellent durability and thermal stability, but the efficiency is still embarrassing. In this work, we intend to address these issues by exploiting CsPbBr3 as light absorber, accompanied by using Cu-phthalocyanine (CuPc) as hole transport material (HTM) and carbon as counter electrode. The optimal device acquires a decent PCE of 6.21%, over 60% higher than those of the HTM-free devices. The systematic characterization and analysis reveal a more effective charge transfer process and a suppressed charge recombination in PSCs after introducing CuPc as hole transfer layer. More importantly, our devices exhibit an outstanding durability and a promising thermal stability, making it rather meaningful in future fabrication and application of PSCs.[Figure not available: see fulltext.

  8. Interface properties of Fe/MgO/Cu-phthalocyanine metal-insulator-organic semiconductor structures

    International Nuclear Information System (INIS)

    Lee, Nyunjong; Bae, Yujeong; Kim, Taehee; Ito, Eisuke; Hara, Masahiko

    2014-01-01

    Hybrid interface structures consisting of organic copper-phthalocyanine (CuPc) and ferromagnetic metal Fe(001) with and without a MgO(001) cover were investigated by using surface sensitive techniques of X-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy. A systematic study of the energy level alignment at the interfaces was carried out. For the hybrid interfaces considered here, our results indicate that the insertion of an artificially-grown ultra-thin oxide layer MgO(001) can prevent Femi level pinning and induce a rather large interface dipole, thereby resulting in remarkable CuPc Fermi level shifts when the thickness of the CuPc film is less than 3 nm. This study provides a better understanding of spin filtering in MgO-based organic spin devices and a new way to alter the interface electronic structure of metal/organic semiconductor hybrid systems.

  9. Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    Energy Technology Data Exchange (ETDEWEB)

    THANH, P. Q.; HOA, N. Q.; CHAU, N. [Vietnam National University, Hanoi (Viet Nam); HUU, C. X. [Danang University of Technology, Danang (Viet Nam); NGO, D. T. [Technical University of Denmark, Kgs. Lyngby (Denmark); PHAN, T. L. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-04-15

    We have studied the magnetic properties of two amorphous alloy ribbons Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Ag{sub 1} (FCSNB-Ag) and Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Cu{sub 1} (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 (T{sub C} ) 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 β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

  10. Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

    International Nuclear Information System (INIS)

    Rajabi, S.K.; Sohrabnezhad, Sh.; Ghafourian, S.

    2016-01-01

    Magnetic Fe 3 O 4 @CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe 3 O 4 @HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe 3 O 4 core and a CuO shell. The Fe 3 O 4 @CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe 3 O 4 -CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent. - Graphical abstract: Fe 3 O 4 @CuO core-shell release of copper ions. These Cu 2+ ions were responsible for the exhibited antibacterial activity. - Highlights: • The Fe 3 O 4 @CuO core-shell was prepared by MOF method. • This is the first study of antibacterial activity of core-shell consist of CuO and Fe 3 O 4 . • The core-shell can be reused effectively. • Core-shell was separated from the reaction solution by external magnetic field.

  11. A review of Pb-Sb(As-S, Cu(Ag-Fe(Zn-Sb(As-S, Ag(Pb-Bi(Sb-S and Pb-Bi-S(Te sulfosalt systems from the Boranja orefield, West Serbia

    Directory of Open Access Journals (Sweden)

    Radosavljević Slobodan A.

    2016-01-01

    Full Text Available Recent mineralogical, chemical, physical, and crystallographic investigations of the Boranja orefield showed very complex mineral associations and assemblages where sulfosalts have significant role. The sulfosalts of the Boranja orefield can be divided in four main groups: (i Pb-Sb(As-S system with ±Fe and ±Cu; (ii Cu(Ag-Fe(Zn-Sb(As-S system; (iii Ag(Pb-Bi(Sb-S; (iv and Pb-Bi-S(Te system. Spatially, these sulfosalts are widely spread, however, they are the most abundant in the following polymetallic deposits and ore zones: Cu(Bi-FeS Kram-Mlakva; Pb(Ag-Zn-FeS2 Veliki Majdan (Kolarica-Centralni revir-Kojići; Sb-Zn-Pb-As Rujevac; and Pb-Zn-FeS2-BaSO4 Bobija. The multi stage formation of minerals, from skarnhydrothermal to complex hydrothermal with various stages and sub-stages has been determined. All hydrothermal stages and sub-stages of various polymetallic deposits and ore zones within the Boranja orefield are followed by a variety of sulfosalts. [Projekat Ministarstva nauke Republike Srbije, br. OI-176016: Magmatism and geodynamics of the Balkan Peninsula from Mesozoic to present day: Significance for the formation of metallic and non-metallic mineral deposits

  12. Facile preparation of magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu composites as high performance Fenton-like catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Li, Keyan; Zhao, Yongqin [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Janik, Michael J. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Song, Chunshan [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); EMS Energy Institute, PSU-DUT Joint Center for Energy Research and Department of Energy & Mineral Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Guo, Xinwen, E-mail: guoxw@dlut.edu.cn [State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2017-02-28

    Highlights: • Fe-Cu composites with different compositions were prepared by calcining tartrates. • Magnetic mesoporous Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining tartrate under N{sub 2}. • Fe{sub 3}O{sub 4}/C/Cu exhibits excellent photo-Fenton catalytic activity and reusability. • The activity is due to the synergistic and photo-reduction effects of Fe and Cu. - Abstract: Fe-Cu composites with different compositions and morphologies were synthesized by a hydrothermal method combined with precursor thermal transformation. γ-Fe{sub 2}O{sub 3}/CuO and α-Fe{sub 2}O{sub 3}/CuO were obtained by calcining the Fe and Cu tartrates under air atmosphere at 350 °C and 500 °C, respectively, while Fe{sub 3}O{sub 4}/C/Cu was obtained by calcining the tartrate precursor under N{sub 2} atmosphere at 500 °C. The Fe{sub 3}O{sub 4}/C/Cu composite possessed mesoporous structure and large surface area up to 133 m{sup 2} g{sup −1}. The Fenton catalytic performance of Fe{sub 3}O{sub 4}/C/Cu composite was closely related to the Fe/Cu molar ratio, and only proper amounts of Fe and Cu exhibited a synergistic enhancement in Fenton catalytic activity. Cu inclusion reduced Fe{sup 3+} to Fe{sup 2+}, which accelerated the Fe{sup 3+}/Fe{sup 2+} cycles and favored H{sub 2}O{sub 2} decomposition to produce more hydroxyl radicals for methylene blue (MB) oxidation. Due to the photo-reduction of Fe{sup 3+} and Cu{sup 2+}, the Fenton catalytic performance was greatly improved when amending with visible light irradiation in the Fe{sub 3}O{sub 4}/C/Cu-H{sub 2}O{sub 2} system, and MB (100 mg L{sup −1}) was nearly removed within 60 min. The Fe{sub 3}O{sub 4}/C/Cu composite showed good recyclability and could be conveniently separated by an applied magnetic field. Compared with conventional methods for mesoporous composite construction, the thermolysis method using mixed metal tartrates as precursors has the advantages of easy preparation and low cost. This strategy provides a facile

  13. 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.

  14. Moessbauer study of isothermally annealed amorphous Fe-Nb-Cu-Si-B alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Toth, I. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia)); Miglierini, M. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava (Slovakia))

    1993-11-01

    Amorphous ribbons of Fe[sub 73.5]Nb[sub 3]Cu[sub 1]Si[sub 13.5]B[sub 9] have been annealed above the crystallization temperature. Annealed samples consisted of crystalline and amorphous phases in a wide temperature range. Two samples of different thicknesses of 33 [mu]m and 27 [mu]m were isothermally annealed at a temperature of 545 C from 0.5 to 5 h in a vacuum furnace. The amount of crystalline phase increases rapidly in the ticker sample. The crystalline part of the Moessbauer spectrum consists of four sharp sextets which can be assigned to a DO[sub 3]-structure FeSi alloy. After 700 C annealing the amorphous phase was not observed and the crystalline phase consisted of the DO[sub 3]-structure FeSi alloy, paramagnetic FeNbB and presumably Fe[sub 23]B[sub 6] and Fe[sub 3]SiB[sub 2]. (orig.)

  15. Structural and dynamical heterogeneity of undercooled Fe{sub 75}Cu{sub 25} melts with miscibility gap

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yu; Wang, Li; Wang, Shenghai, E-mail: shenghaiw@163.com; Li, Xuelian; Cui, Wenchao

    2014-12-05

    Highlights: • We simulate the undercooled Fe{sub 75}Cu{sub 25} melts with miscibility gap at atomic level. • Fe{sub 75}Cu{sub 25} melts separate into Cu-rich and Fe-rich liquid upon relaxation. • The process is controlled by the nucleation and grows mechanism. • Both PPCFs and CN confirm that L–L phase separation is a successive process. - Abstract: Molecular dynamics simulation (MD) based upon the developed embedded atom method (EAM) has been performed to explore the structural and dynamical heterogeneity of Fe{sub 75}Cu{sub 25} melts. The results show that the melts separate into Cu-rich droplets surround by the Fe-rich matrix controlled by nucleation and growth mechanism. The larger undercoolings suggest the higher nucleation rate and growth rate of droplets. The growth of droplet is achieved by the aggregation and coagulation of neighbor droplet with the characteristics of collective movement for homogeneous atoms. A sharp increase of S{sub CC} (q = 0) is found at all simulated temperature, which means concentration fluctuation on large length scales are much pronounced. Both partial pair correlation functions (PPCFs) and coordination number (CN) confirm that liquid–liquid (L–L) phase separation is a successive process with a stronger interaction of homogeneous pairs than that of heterogeneous pairs in Fe{sub 75}Cu{sub 25} melts. The studies above characterize the phase separation of metal melts on the atomic scale.

  16. Simultaneous preconcentration of Cu, Fe and Pb as methylthymol blue complexes on naphthalene adsorbent and flame atomic absorption determination

    International Nuclear Information System (INIS)

    Pourreza, Nahid; Hoveizavi, Reza

    2005-01-01

    A simultaneous preconcentration method was developed for determination of trace amounts of Cu, Fe and Pb by atomic absorption spectrometry. The method is based on the retention of their methylthymol blue complexes by naphthalene methyltrioctyl ammonium chloride adsorbent in a column. The adsorbed metal complexes were eluted from the column with nitric acid and Cu, Fe and Pb were determined by flame atomic absorption spectrometry. Several parameters such as pH of the sample solution, ligand concentration, volume of the sample and the amount of methyltrioctyl ammonium chloride loaded on naphthalene were evaluated. The effect of diverse ions on the preconcentration was also investigated. A preconcentration factor of up to 100 or more can easily be achieved depending on the volume of the sample taken. The calibration graphs were obtained in the range of 5-40, 10-100 and 10-200 ng ml -1 for Cu, Fe and Pb in the initial solution, respectively, when using 500 ml of the solution. The detection limit based on three standard deviations of the blank was 0.54, 3.1, and 4.5 ng ml -1 for Cu, Fe and Pb, respectively. The relative standard deviations (R.S.D.) of 0.62-1.4% for Cu, 1.9-3.4% for Fe and 1.0-2.2% for Pb were obtained. The method was applied to the determination of Cu, Fe and Pb in river and wastewater samples

  17. Novel Chiral Magnetic Domain Wall Structure in Fe/Ni/Cu(001) Films

    Science.gov (United States)

    Chen, G.; Zhu, J.; Quesada, A.; Li, J.; N'Diaye, A. T.; Huo, Y.; Ma, T. P.; Chen, Y.; Kwon, H. Y.; Won, C.; Qiu, Z. Q.; Schmid, A. K.; Wu, Y. Z.

    2013-04-01

    Using spin-polarized low energy electron microscopy, we discovered a new type of domain wall structure in perpendicularly magnetized Fe/Ni bilayers grown epitaxially on Cu(100). Specifically, we observed unexpected Néel-type walls with fixed chirality in the magnetic stripe phase. Furthermore, we find that the chirality of the domain walls is determined by the film growth order with the chirality being right handed in Fe/Ni bilayers and left handed in Ni/Fe bilayers, suggesting that the underlying mechanism is the Dzyaloshinskii-Moriya interaction at the film interfaces. Our observations may open a new route to control chiral spin structures using interfacial engineering in transition metal heterostructures.

  18. Eutectic Al-Si-Cu-Fe-Mn alloys with enhanced mechanical properties at room and elevated temperature

    International Nuclear Information System (INIS)

    Wang, E.R.; Hui, X.D.; Chen, G.L.

    2011-01-01

    Highlights: → Fabricated a kind of high performance Al-Si alloy with low production costs. → Clarified two different morphologies of α-Fe and corresponding crystal structures. → Analyzed the crystallography of Cu-rich phases before and after T6 treatment. → Fracture mechanism of precipitates in experimental alloys during tensile process. -- Abstract: In this paper, we report a novel kind of eutectic Al-Si-Cu-Fe-Mn alloy with ultimate tensile strength up to 336 MPa and 144.3 MPa at room temperature and 300 o C, respectively. This kind of alloy was prepared by metal mold casting followed by T6 treatment. The microstructure is composed of eutectic and primary Si, α-Fe, Al 2 Cu and α-Al phases. Iron-rich phases, which were identified as BCC type of α-Fe (Al 15 (Fe,Mn) 3 Si 2 ), exist in blocky and dendrite forms. Tiny blocky Al 2 Cu crystals disperse in α-Fe dendrites or at the grain boundaries of α-Al. During T6 treatment, Cu atoms aggregate from the super-saturation solid solution to form GP zones, θ'' or θ'. Further analysis found that the enhanced mechanical properties of the experimental alloy are mainly attributed to the formation of α-Fe and copper-rich phases.

  19. Theoretical study of the superhyperfine parameters for Cu{sup 2+} in K{sub 2}PdX{sub 4} (X = Cl, Br)

    Energy Technology Data Exchange (ETDEWEB)

    Wei, L. H.; Wu, S. Y., E-mail: shaoyi_wu@163.com; Zhang, Z. H.; Wang, X. F.; Hu, Y. X. [University of Electronic Science and Technology of China, Department of Applied Physics (China)

    2008-01-15

    The superhyperfine parameters T{sub j} (j = x, y, z) for Cu{sup 2+} in the square-planar K{sub 2}PdX{sub 4} (X = Cl, Br) are theoretically studied from the perturbation formulas of these parameters for an octahedral 3d{sup 9} cluster, by considering both the contributions from the crystal-field and charge-transfer mechanisms. The related molecular orbital coefficients are determined from the cluster approach in a uniform way. Based on one adjustable proportional factor {rho} for the orbital admixture coefficients, the calculated results of present work show reasonable agreement with the observed values.

  20. 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)

    Tang, Mingyi; Zhang, Sai; Li, Xianxian; Pang, Xiaobo; Qiu, Haixia

    2014-01-01

    A facile and efficient approach to synthesize Fe 3 O 4 @Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe 3 O 4 @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 Fe 3 O 4 contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe 3 O 4 @Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe 3 O 4 @Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe 3 O 4 @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 Fe 3 O 4 @Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe 3 O 4 @Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe 3 O 4 @Cu display high catalytic activity after 13 cycles

  1. Fabrication of magnetically recyclable Fe{sub 3}O{sub 4}@Cu nanocomposites with high catalytic performance for the reduction of organic dyes and 4-nitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Mingyi, E-mail: mingyitjucu@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Zhang, Sai; Li, Xianxian; Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia [School of Science, Tianjin University, Tianjin 300072 (China)

    2014-12-15

    A facile and efficient approach to synthesize Fe{sub 3}O{sub 4}@Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe{sub 3}O{sub 4}@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 Fe{sub 3}O{sub 4} contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe{sub 3}O{sub 4}@Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe{sub 3}O{sub 4}@Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe{sub 3}O{sub 4}@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 Fe{sub 3}O{sub 4}@Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe{sub 3}O{sub 4}@Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe{sub 3}O{sub 4}@Cu display high catalytic activity after 13 cycles.

  2. Two different one-dimensional structural motifs in [catena-{Cu(tacn)}2Pd(CN)4]Br2.[catena-Cu(tacn)Pd(CN)4]2.H2O (tacn is 1,4,7-triazacyclononane).

    Science.gov (United States)

    Kuchár, Juraj; Cernák, Juraj

    2009-07-01

    The title compound, catena-poly[[bis[(triazacyclononane-kappa(3)N,N',N'')copper(II)]-di-mu-cyanido-kappa(4)N:C-palladate(II)-di-mu-cyanido-kappa(4)C:N] dibromide bis[[(triazacyclononane-kappa(3)N,N',N'')copper(II)]-mu-cyanido-kappa(2)N:C-[dicyanidopalladate(II)]-mu-cyanido-kappa(2)C:N] monohydrate], {[Cu(2)Pd(CN)(4)(C(6)H(15)N(3))(2)]Br(2).[Cu(2)Pd(2)(CN)(8)(C(6)H(15)N(3))(2)].H(2)O}(n), (I), was isolated from an aqueous solution containing tacn.3HBr (tacn is 1,4,7-triazacyclononane), Cu(2+) and tetracyanidopalladate(2-) anions. The crystal structure of (I) is essentially ionic and built up of 2,2-electroneutral chains, viz. [Cu(tacn)(NC)-Pd(CN)(2)-(CN)-], positively charged 2,4-ribbons exhibiting the composition {[Cu(tacn)(NC)(2)-Pd(CN)(2)-Cu(tacn)](2n+)}(n), bromide anions and one disordered water molecule of crystallization. The O atom of the water molecule occupies two unique crystallographic positions, one on a centre of symmetry, which is half occupied, and the other in a general position with one-quarter occupancy. One of the tacn ligands also exhibits disorder. The formation of two different types of one-dimensional structural motif within the same structure is a unique feature of this compound.

  3. A facile approach to fabricate of photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Baolong; Shan, Yan, E-mail: shanyan@qust.edu.cn; Chen, Kezheng, E-mail: kchen@qust.edu.cn

    2017-06-01

    Photothermal functional Fe{sub 3}O{sub 4}@CuS microspheres have been prepared successfully by a simple chemical deposition method. The adsorption of cetyltrimethyl-ammonium bromide (CTAB) on the magnetic microspheres plays an important role in forming the structure of the composites. The present materials are characterized with XRD, TEM, SEM, FTIR, and UV-VIS-NIR spectrophotometer. The results show that Fe{sub 3}O{sub 4} microspheres are coated by CuS layer with thickness of 10 nm. The saturation magnetization value of Fe{sub 3}O{sub 4}@CuS core-shell microspheres is 27 emu/g at room temperature and the sample possesses excellent magnetic response in the presence of applied magnetic field. Moreover, these microspheres exhibit good dispersion, suitable size and significant photothermal conversion efficiency up to 20.7% at 808 nm laser irradiation. Fluctuation value of the highest temperature of Fe{sub 3}O{sub 4}@CuS dispersion over four times LASER ON/OFF indicates that photothermal stability of Fe{sub 3}O{sub 4}@CuS microspheres is good. - Highlights: • The Fe{sub 3}O{sub 4} microspheres have been coated with CuS and the thickness of CuS layer is about 10 nm. • The Fe{sub 3}O{sub 4}@CuS microspheres are ferromagnetism, and possess good photothermal conversion efficiency and photostability. • The materials have great potential application for photothermal therapy.

  4. Magnetoresistance peak in the mixed state of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br

    International Nuclear Information System (INIS)

    Zuo, F.

    1997-01-01

    In this letter, the authors report transport measurements with field and current parallel to the b axis (perpendicular to the conducting plane) in the organic superconductor κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br. The isothermal magnetoresistance R(H) displays a peak effect as a function of field. The peak resistance is substantially larger than that in large fields. The results are in sharp contrast to the conventional dissipation mechanisms in the mixed state of anisotropic superconductors, as in the case of Bi 2 Sr 2 CaCu 2 O 8 . Comparison with H c2 (T) obtained from magnetic measurements shows that the peak effect in R(H) occurs in the mixed state. Analysis of the data suggests a much larger Josephson junction resistance in the mixed state than that in the normal state, indicative of a new charge transport scattering mechanism in the presence of vortices

  5. The influence of cooling rate and Fe/Cr content on the evolution of Fe-rich compounds in a secondary Al-Si-Cu diecasting alloy

    Science.gov (United States)

    Fabrizi, A.; Timelli, G.

    2016-03-01

    This study investigates the morphological evolution of primary α-Al(Fe,Mn,Cr)Si phase in a secondary Al-Si-Cu alloy with respect to the initial Fe and Cr contents as well as to the cooling rate. The solidification experiments have been designed in order to cover a wide range of cooling rates, and the Fe and Cr contents have been varied over two levels. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes occurring at different experimental conditions. The morphological evolution of the α-Fe phase has been also analysed by observing deep etched samples. By changing the cooling rate, α-Al15(Fe,Mn,Cr)3Si2 dodecahedron crystals, as well as Chinese- script, branched structures and dendrites form, while primary coarse β-Al5(Fe,Mn)Si needles appear in the alloy with the highest Fe content at low cooling rates.

  6. The influence of cooling rate and Fe/Cr content on the evolution of Fe-rich compounds in a secondary Al-Si-Cu diecasting alloy

    International Nuclear Information System (INIS)

    Fabrizi, A; Timelli, G

    2016-01-01

    This study investigates the morphological evolution of primary α-Al(Fe,Mn,Cr)Si phase in a secondary Al-Si-Cu alloy with respect to the initial Fe and Cr contents as well as to the cooling rate. The solidification experiments have been designed in order to cover a wide range of cooling rates, and the Fe and Cr contents have been varied over two levels. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes occurring at different experimental conditions. The morphological evolution of the α-Fe phase has been also analysed by observing deep etched samples. By changing the cooling rate, α-Al 15 (Fe,Mn,Cr) 3 Si 2 dodecahedron crystals, as well as Chinese- script, branched structures and dendrites form, while primary coarse β-Al 5 (Fe,Mn)Si needles appear in the alloy with the highest Fe content at low cooling rates. (paper)

  7. Evaluation of the potential impact of Cu competition on the performance of o,o-FeEDDHA in soil applications

    OpenAIRE

    Schenkeveld, W.D.C.; Weng, L.P.; Reichwein, A.M.; Temminghoff, E.J.M.; Riemsdijk, van, W.H.

    2015-01-01

    Ferric ethylene diamine-N,N'-bis(hydroxy phenyl acetic acid) (FeEDDHA)-based iron (Fe) fertilizers are commonly applied to plants grown on calcareous soils and comprise a mixture of FeEDDHA components. Upon application to the soil, the pore water concentrations of the active ingredients racemic and meso o,o-FeEDDHA show a gradual decline unrelated to plant uptake or biodegradation. In the present study, the potential of soil copper (Cu) to reduce the effectiveness of FeEDDHA-based fertilizers...

  8. Effect of CeLa addition on the microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jiandi [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Ding, Dongyan, E-mail: dyding@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, Zhou; Zhang, Junchao; Zhang, Wenlong [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yongjin; Chen, Guozhen; Chen, Weigao; You, Xiaohua [Huafon NLM Al Co., Ltd, Shanghai 201506 (China); Chen, Renzong; Huang, Yuanwei; Tang, Jinsong [Shanghai Huafon Materials Technology Institute, Shanghai 201203 (China)

    2017-01-15

    Development of high strength lithium battery shell alloy is highly desired for new energy automobile industry. The microstructures and mechanical properties of Al-Cu-Mn-Mg-Fe alloy with different CeLa additions were investigated through optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Rietveld refinement and tensile testing. Experimental results indicate that Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed due to CeLa addition. Addition of 0.25 wt.% CeLa could promote the formation of denser precipitation of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe) phases, which improved the mechanical properties of the alloy at room temperature. However, up to 0.50 wt.% CeLa addition could promote the formation of coarse Al{sub 8}Cu{sub 4}Ce phase, Al{sub 6}Cu{sub 6}La phase and Al{sub 6}(Mn, Fe) phase, which resulted in weakened mechanical properties. - Highlights: •Al-Cu-Mn-Mg-Fe alloys with different CeLa addition were fabricated through casting and rolling. •Al{sub 8}Cu{sub 4}Ce and Al{sub 6}Cu{sub 6}La phases formed after CeLa addition. •Addition of 0.25 wt.% CeLa promoted formation of denser precipitates of Al{sub 20}Cu{sub 2}Mn{sub 3} and Al{sub 6}(Mn, Fe). •Mechanical properties of the alloy was improved after 0.25 wt.% CeLa addition.

  9. Charge dynamics of 57Fe probe atoms in La2Li0.5Cu0.5O4

    Science.gov (United States)

    Presniakov, I. A.; Sobolev, A. V.; Rusakov, V. S.; Moskvin, A. S.; Baranov, A. V.

    2018-06-01

    The objective of this study is to characterize the electronic state and local surrounding of 57Fe Mössbauer probe atoms within iron-doped layered perovskite La2Li0.5Cu0.5O4 containing transition metal in unusual formal oxidation states "+3". An approach based on the qualitative energy diagrams analysis and the calculations within the cluster configuration interaction method have been developed. It was shown that a large amount of charge is transferred via Cu-O bonds from the O: 2p bands to the Cu: 3d orbitals and the ground state is dominated by the d9L configuration ("Cu2+-O-" state). The dominant d9L ground state for the (CuO6) sublattice induces in the environment of the 57Fe probe cations a charge transfer Fe3+ + O-(L) → Fe4+ + O2-, which transforms "Fe3+" into "Fe4+" state. The experimental spectra in the entire temperature range 77-300 K were described with the use of the stochastic two-level model based on the assumption of dynamic equilibrium between two Fe3+↔Fe4+ valence states related to the iron atom in the [Fe(1)O4]4- center. The relaxation frequencies and activation energies of the corresponding charge fluctuations were estimated based on Mössbauer data. The results are discussed assuming a temperature-induced change in the electronic state of the [CuO4]5- clusters in the layered perovskite.

  10. Evolution of Primary Fe-Rich Compounds in Secondary Al-Si-Cu Alloys

    Science.gov (United States)

    Fabrizi, Alberto; Capuzzi, Stefano; Timelli, Giulio

    Although iron is usually added in die cast Al-Si foundry alloys to prevent die soldering, primary Fe-rich particles are generally considered as "hardspot" inclusions which compromise the mechanical properties of the alloy, namely ductility and toughness. As there is no economical methods to remove the Fe excess in secondary Al-Si alloys at this time, the control of solidification process and chemical composition of the alloy is a common industrial practice to overcome the negative effects connected with the presence of Fe-rich particles. In this work, the size and morphology as well as the nucleation density of primary Fe-rich particles have been studied as function of cooling rate and alloy chemical composition for secondary Al-Si-Cu alloys. The solidification experiments were carried out using differential scanning calorimetry whereas morphology investigations were conducted using optical and scanning electron microscopy. Mcrosegregations and chemical composition of primary Fe-rich particles were examined by energy dispersive spectroscopy.

  11. Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

    International Nuclear Information System (INIS)

    Chemin, Aline; Marques, Denys; Bisanha, Leandro; Motheo, Artur de Jesus; Bose Filho, Waldek Wladimir; Ruchert, Cassius Olivio Figueiredo

    2014-01-01

    Highlights: • The corrosion on new aerospace aluminum alloy is studied. • Al 7 Cu 2 Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy. • Al 7 Cu 2 Fe particles have different morphologies depending on the forming process. • Corrosion pitting occurs around Al 7 Cu 2 Fe precipitates in 7475-T7351 and 7081-T73511 alloys. - Abstract: The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al 7 Cu 2 Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al 7 Cu 2 Fe precipitate in both alloys, revealing the anodic behavior of the matrix

  12. Mecano-synthesis of the alloy 25%Fe-50%Cu-25%Nb

    International Nuclear Information System (INIS)

    Sousa, Keytiane; Oliveira, Michel Picanco de; Guimaraes, Renan da Silva; Moreira Junior, Valdenir; Filgueira, Marcello

    2016-01-01

    In general, this study aims at the application of mechanical grinding to the system 25% Fe-50% Cu-25% Nb and studies the production process of these powders during milling. The evolution of the structure during the synthesis and the effect of variation of the grinding time were studied by diffraction of X-rays (XRD) and Scanning Electron Microscopy coupled EDS (SEM + EDS) in order to obtain the sizes of crystallites, the phase formation and its evolution with grinding time, and also the homogeneity of the mixture. The particle size distribution was analyzed by laser sedigraph technique. The powders synthesis were performed for milling time of 2.5, 5 and 10 hours. The mechanical grinding showed to be effective with the solid solution formation in the early grinding times. The XRD showed the solid solution formation with subsequent reduction and disappearance of Cu peaks. Through the technique of laser sedigraph it was observed the increase of the particle size followed by the its reduction in the milling time of 10h, a fact that characterizes the mechanical grinding process for ductile powder particles. Thus, the study demonstrated the effectiveness of the mechanical grinding to obtain powder of Fe-Cu-Nb and further processing and application of diamond cutting tools. (author)

  13. APFIM investigation of clustering in neutron-irradiated Fe-Cu alloys and pressure vessel steels

    International Nuclear Information System (INIS)

    Auger, P.; Pareige, P.; Blavette, D.

    1996-01-01

    Pressure vessel steels used in PWRs are known to be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are commonly supposed to result from the formation of point defects, dislocation loops, voids and copper-rich precipitates. However, the real nature of the irradiation induced damage, in these particularly low copper steels (>0,1 wt%), has not been clearly identify yet. A new experimental work has been carried out thanks to atom probe and field ion microscopy (APFIM) facilities and, more particularly with a new generation of atom probe recently developed, namely the tomographic atom probe (TAP), in order to improve: the understanding of the complex behavior of copper precipitation which occurs when low-alloyed Fe-Cu model alloys are irradiated with neutrons; the microstructural characterization of the pressure vessel steel of the CHOOZ A reactor under various fluences (French Surveillance Programme). The investigations clearly reveal the precipitation of copper-rich clusters in irradiated Fe-Cu alloys while more complicated Si, Ni, Mn and Cu-solute 'clouds' were observed to develop in the low-copper ferritic solid solution of the pressure vessel steel. (authors)

  14. Estimated daily intake of Fe, Cu, Ca and Zn through common cereals in Tehran, Iran.

    Science.gov (United States)

    Kashian, S; Fathivand, A A

    2015-06-01

    This paper presents the findings of study undertaken to estimate the dietary intake of iron (Fe), copper (Cu), calcium (Ca) and zinc (Zn) through common cereals in Tehran, Iran. 100 samples of rice, wheat and barley were collected from various brands between August and October 2013. The samples were analyzed performing instrumental neutron activation analysis (INAA). The dietary intake for adults was estimated by a total cereal study. Calculations were carried out on the basis of the reported adults' average food consumption rate data. The total daily intake estimated in mgd(-1) for Tehran population were 3.6 (Fe), 10.2 (Zn), 0.3 (Cu) and 234.5 (Ca). Wheat showed the highest contribution to Zn, Cu and Ca intakes. Furthermore, intakes were compared with recommended dietary allowance (RDA). Zn total intake (10.2mgd(-1)) was comparable with RDA values for males (11mgd(-1)) and was higher than recommended value for females (8mgd(-1)). The intakes of other studied elements were below the respective RDAs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Vibrational properties of stannite and kesterite type compounds: Raman scattering analysis of Cu2(Fe,Zn)SnS4

    International Nuclear Information System (INIS)

    Fontané, X.; Izquierdo-Roca, V.; Saucedo, E.; Schorr, S.; Yukhymchuk, V.O.; Valakh, M.Ya.; Pérez-Rodríguez, A.; Morante, J.R.

    2012-01-01

    Highlights: ► Analysis of main and weaker Raman peaks from Cu 2 FeZnS 4 and Cu 2 ZnSnS 4 compounds. ► Identification of a cation disorder induced Raman peak in Cu 2 ZnSnS 4 . ► Analysis of spectral features of main Raman peaks from Cu 2 (Fe,Zn)SnS 4 . - Abstract: This work reports the analysis of the vibrational properties of stannite–kesterite Cu 2 (Fe,Zn)SnS 4 compounds that has been performed by Raman scattering measurements. The detailed analysis of the experimental spectra has allowed determining the frequency and symmetry assignment of the main and weaker peaks from both stannite Cu 2 FeSnS 4 (CFTS) and kesterite Cu 2 ZnSnS 4 (CZTS) phases. The measurements performed in the kesterite CZTS samples have also revealed the presence of local inhomogeneities that are characterised by an additional peak in the spectra at about 331 cm −1 . This peak has been related to the presence in these local regions of a high degree of disorder in the cation sublattice, in agreement with previous neutron diffraction analysis in similar samples. Finally, the spectra from the solid solution alloys show a one-mode behaviour of the main A/A 1 peak with the chemical composition.

  16. Effects of surface crystallization and oxidation in nanocrystalline FeNbCuSiB(P) ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Butvinová, B., E-mail: beata.butvinova@savba.sk [Institute of Physics SAS, Dúbravská cesta 9, 845 11 Bratislava (Slovakia); Butvin, P. [Institute of Physics SAS, Dúbravská cesta 9, 845 11 Bratislava (Slovakia); Brzózka, K. [Department of Physics, University of Technology and Humanities in Radom, Krasickiego 54, 26-600 Radom (Poland); Kuzminski, M. [Institute of Physics PAS, Al. Lotnikow 36/42, 02-668 Warsaw (Poland); Maťko, I.; Švec Sr, P. [Institute of Physics SAS, Dúbravská cesta 9, 845 11 Bratislava (Slovakia); Chromčíková, M. [Institute of Inorg. Chem. SAS, Centrum VILA, Študentská 2, 911 50 Trenčín (Slovakia)

    2017-02-15

    Si-poor Fe{sub 74}Nb{sub 3}Cu{sub 1}Si{sub 8}B{sub 14−x}P{sub x}, (x=0, 3) nanocrystalline ribbon-form alloys often form surfaces, which exert in-plane force on underlying ribbon interior when nanocrystallized in even modest presence of oxygen. Mostly unwanted hard-ribbon-axis magnetic anisotropy is standard result. Essential sources of the surface-caused stress have been sought and influence of P instead of B substitution on this effect was studied too. Preferred surface crystallization (PSC) was found to be the major reason. However P substitution suppresses PSC and promotes Fe-oxide formation, which eases the stress, softens the surfaces and provides different annealing evolution of surface properties. - Highlights: • Ar anneal of low-Si FeNbCuBSi ribbons produce surfaces that stress ribbon interior. • The stress comes mainly from preferred crystallization of surfaces. • Partial substitution of B by P changes annealing evolution of surface properties. • Without P, more crystalline surfaces significantly reduce ribbon's elasticity. • P suppresses surface crystallinity, promotes oxides and reduces mutual stress.

  17. Magnetic and surface properties of Fe-Nb (Mo, V)-Cu-B-Si ribbons

    International Nuclear Information System (INIS)

    Butvinova, B.; Butvin, P.; Svec, P. Sr.; Matko, I.; Svec, P.; Janickovic, D.; Kadlecikova, M.

    2014-01-01

    The rapidly quenched Finemet (FeNbCuBSi) ribbons prepared by planar flow casting of the melt are very variable to obtain very good soft-magnetic properties. An appropriate thermal treatment leading to ultra-fine grain structure enables to attain such properties as desired for practical use. Increasing Fe percentage to the detriment of non-magnetic components lifts saturation induction above 1.3 T, preserves low coercivity and makes the alloy even cheaper to suit its mass production for use in power electronics. Apart from the plenty of benefits the ribbons show some risks. One of them is macroscopic heterogeneity, which often manifests via differences between surfaces and interior of a ribbon [3]. The surfaces squeeze (by in-plane force) the interior of many such ribbons and if engaged in magnetoelastic interaction, the force affects the resulting magnetic anisotropy [4]. Current research shows that changes of hysteresis loop shape come rather from surface crystallization and not from oxides namely in positively magnetostrictive alloys FeNbCuBSi known as low- Si Finemets. The object of this work is to verify whether the substitution of another element instead of Nb (usually incorporated as the grain-growth blocker) can change surface properties and affects the resulting magnetic properties. We chose V and Mo instead of Nb. Oxides, oxyhydroxides and a possible squeezing layer was looked for after higher temperature annealing which ensures partially nanocrystalline structure. (authors)

  18. Frustrated magnetization in PrxLa1-xBaCuO5Fe

    International Nuclear Information System (INIS)

    Ortiz, W.A.; Araujo-Moreira, F.M.; Prassides, K.

    1999-01-01

    The crystal structure of the system Pr x La 1-x BaCuO 5 Fe has been recently reviewed. The magnetic structure of samples with x = 0 and x = 1 is mainly due to effective local moments of iron and copper. In Pr-rich samples, Fe ions occupy two non-equivalent positions, making it substantially plausible that two or more magnetic subsets might coexist in the system. This contribution presents magnetization studies on five samples of the Pr x La 1-x BaCuO 5 Fe system (x = 0.0, 0.2, 0.5, 0.7 and 1.0). All samples exhibit a strong irreversible behavior between zero-field-cooled and field-cooled procedures below a certain irreversibility temperature T i . Above T i , both branches are coincident and well described by a Curie-Weiss fitting. Decreasing the temperature below T i , the zero-field-cooled response increases less than the field-cooled curve, indicating some degree of frustrated antiferromagnetic couplings. (orig.)

  19. Note: Erosion of W-Ni-Fe and W-Cu alloy electrodes in repetitive spark gaps.

    Science.gov (United States)

    Wu, Jiawei; Han, Ruoyu; Ding, Weidong; Qiu, Aici; Tang, Junping

    2018-02-01

    A pair of W-Ni-Fe and W-Cu electrodes were tested under 100 kA level pulsed currents for 10 000 shots, respectively. Surface roughness and morphology characteristics of the two pairs of electrodes were obtained and compared. Experimental results indicated cracks divided the W-Cu electrode surface to polygons while the W-Ni-Fe electrode surface remained as a whole with pits and protrusions. Accordingly, the surface roughness of W-Ni-Fe electrodes increased to ∼3 μm while that of W-Cu electrodes reached ∼7 μm at the end of the test. The results reveal that the W-Ni-Fe alloy has a better erosion resistance and potential to be further applied in spark gaps.

  20. Magnetic properties of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yao, Jinlei [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

    2015-12-15

    Magnetic properties and magnetocaloric effect of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds have been investigated. Magnetic measurements of RNi{sub 3}TSi display the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Graphical abstract: Magnetic measurements of RNi{sub 3}TSi show the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of 'RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi'. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Highlights: • CaCu{sub 5}-type RNi{sub 3}TSi show ferromagnetic ordering (R=Gd, Tb, T=Mn–Co, Cu). • Curie point increases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • MCE decreases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. • The coercive field of TbNi{sub 3}MnSi and TbNi{sub 3}FeSi reach 13 kOe and 16 kOe at 5 K.

  1. 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

    2014-04-07

    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.

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

    International Nuclear Information System (INIS)

    Liu, K.M.; Lu, D.P.; Zhou, H.T.; Atrens, A.; Zou, J.; Yang, Y.L.; Zeng, S.M.

    2010-01-01

    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(A 0 /A) and A 0 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.

  3. 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.; Aftab, M.; Anjum, Dalaver H.; Cha, Dong Kyu; Poirier, Gerald; Ismat Shah, S.

    2015-01-01

    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.

  4. 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.

  5. A study of copper precipitation in the thermally aged FeCu alloy using SANS

    Energy Technology Data Exchange (ETDEWEB)

    Park, D. G.; Kim, J. H.; Kwon, S. C.; Kim, W. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Lee, M. N.; Koo, Y. M. [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2005-07-01

    The continued operation or lifetime extension of a number of nuclear power plant around the world requires an understanding of the damage imparted to the reactor pressure vessel (RPV) steel by radiation. Irradiation embrittlement of nuclear reactor pressure vessel steels results from a high number of nanometer sized Cu rich precipitates (CRPs) and sub-nanometer defect-solute clusters. The copper precipitation leads to a distortion of the crystal lattice surrounding the copper precipitates and yields an internal micro-stress. In order to study the effect of copper precipitation on the steel embrittlement under neutron irradiation, the characteristics of nano size defects were investigated using small angle neutron scattering (SANS) in the thermal aged FeCu model alloys. The results on the precipitation composition, number density, size distribution and matrix composition obtained using a high resolution TEM and SANS are compared and contrasted.

  6. Mechanical properties of Fe-Mn-Cu-Al alloy systems and optimization of their composition

    International Nuclear Information System (INIS)

    Tkachenko, I.F.; Baranov, A.A.

    1981-01-01

    Studied is the separate and combined effect of Cu and Al on mechanical properties of the Fe-Mn-Al-Cu system alloys using a simplex- lattice method of experiment planning. Heat treated specimens in the form of plates have been subjected to mechanical tests. It is shown that mechanical properties of studied alloys change sufficiently in the result of tempering in heterogeneous (α+γ) region. Studied alloys have the most favourable conbination of characteristics of strength, plasticity and impact strength after tempering at 630 deg C during 2 hours. Diagrams are obtained which characterizes dependence of mechanical properties of alloys on their composition. They permit to select optimum compositions of alloys with the necessary combination of strength, plasticity and impact strength [ru

  7. A novel lithium copper iron phosphate with idealized formula Li5Cu22+Fe3+(PO44: crystal structure and distribution of defects

    Directory of Open Access Journals (Sweden)

    Shailesh Upreti

    2011-05-01

    Full Text Available Gray–green single crystals were obtained under high-pressure, high-temperature hydrothermal conditions. A refinement of atom occupancies gave the composition Li3.68Cu2+Fe3+(Cu0.55Li0.452Fe2+0.15(PO44. The structure is built from triplets of edge-sharing (Cu,LiO5–FeO6–(Cu,LiO5 polyhedra, CuO4 quadrilaterals and PO4 tetrahedra. In the (Cu,LiO5 polyhedra the Cu and Li positions are statistically occupied in a 0.551 (2:0.449 (2 ratio. Both FeO6 and CuO4 polyhedra exhibit overline1 symmetry. The positions of additional Li atoms with vacancy defects are in the interstices of the framework.

  8. 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.

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

    KAUST Repository

    Zhang, Tao; Chen, Yin; Leiknes, TorOve

    2016-01-01

    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) 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.

  10. The synthesis of higher alcohols from CO2 hydrogenation with Co, Cu, Fe-based catalysts

    International Nuclear Information System (INIS)

    Ji, Qinqin

    2017-01-01

    CO 2 is a clean carbon source for the chemical reactions, many researchers have studied the utilization of CO 2 . Higher alcohols are clean fuel additives. The synthesis of higher alcohols from CO hydrogenation has also been studied by many researchers, but there are few literatures about the synthesis of higher alcohols from CO 2 hydrogenation, which is a complex and difficult reaction. The catalysts that used for higher alcohols synthesis need at least two active phases and good cooperation. In our study, we tested the Co. Cu. Fe spinel-based catalysts and the effect of supports (CNTs and TUD-1) and promoters (K, Na, Cs) to the HAS reaction. We found that catalyst CuFe-precursor-800 is beneficial for the synthesis of C2+ hydrocarbons and higher alcohols. In the CO 2 hydrogenation, Co acts as a methanation catalyst rather than acting as a FT catalyst, because of the different reaction mechanism between CO hydrogenation and CO 2 hydrogenation. In order to inhibit the formation of huge amount of hydrocarbons, it is better to choose catalysts without Co in the CO 2 hydrogenation reaction. Compared the functions of CNTs and TUD-1, we found that CNTs is a perfect support for the synthesis of long-chain products (higher alcohols and C2+ hydrocarbons). The TUD-1 support are more suitable for synthesis of single-carbon products (methane and methanol).The addition of alkalis as promoters does not only lead to increase the conversion of CO 2 and H 2 , but also sharply increased the selectivity to the desired products, higher alcohols. The catalyst 0.5K30CuFeCNTs owns the highest productivities (370.7 g.kg -1 .h -1 ) of higher alcohols at 350 C and 50 bar. (author) [fr

  11. The Effect of Substitution of Fe By Co on Rapidly Quenched (FeCoMoCuB Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Marek Paluga

    2005-01-01

    Full Text Available (Fe1-xCox79Mo8Cu1B15 amorphous alloys ware prepared in the form of ribbons by rapid quenching for x=0. 0.25 and 0.5. The effect of variation of Co/Fe ratio is analyzed with respect to the formation of amorphous state and to transformation of the structure into nancrystalline phases formed after subsequent thermal treatment. Selected properties and atomic structure in as-quenched state are studied by TEM, AFM, XRD any by measurement of magnetoresistance characteristics. The influence of heat treatment on transport and magnetic properties is shown on temperature dependencies of electrical resistivity and magnetization. It was founf that while the increase of Co content leads to the increase of Curie temperature of as-quenched structure, transition to nanocrystalline state is not affected in a significant manner. The as-quenched state for alloy without Co was found to contain thin crystal-containing layer which, however, was observed, contary to general behavior, at the side of the ribbon exposed to higher quenching rates.

  12. Investigations of CuFeS{sub 2} semiconductor mineral from ocean rift hydrothermal vent fields by Cu NMR in a local field

    Energy Technology Data Exchange (ETDEWEB)

    Matukhin, V. L.; Pogoreltsev, A. I.; Gavrilenko, A. N., E-mail: ang-2000@mail.ru; Garkavyi, S. O.; Shmidt, E. V. [Kazan State Power University (Russian Federation); Babaeva, S. F. [All-Russia Research Institute of Geology and Mineral Resources of the World Ocean “VNIIOkeangeologiya” (Russian Federation); Sukhanova, A. A. [Saint-Petersburg Mining University (Russian Federation); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2017-01-15

    The results of investigating natural samples of chalcopyrite mineral CuFeS{sub 2} from massive oceanic sulfide ores of the Mid-Atlantic ridge by the {sup 63}Cu nuclear magnetic resonance (NMR {sup 63}Cu) in a local field at room temperature are presented. The significant width of the resonance lines found in the {sup 63}Cu NMR spectrum directly testifies to a wide distribution of local magnetic and electric fields in the investigated chalcopyrite samples. This distribution can be the consequence of an appreciable deviation of the structure of the investigated chalcopyrite samples from the stoichiometric one. The obtained results show that the pulsed {sup 63}Cu NMR can be an efficient method for studying the physical properties of deep-water polymetallic sulfides of the World Ocean.

  13. Thermal stability of Al-Cu-Fe quasicrystals prepared by SHS method

    Directory of Open Access Journals (Sweden)

    Pavel Novak

    2013-02-01

    Full Text Available Quasicrystal-containing materials are usually prepared by rapid solidification of the melt (e.g. by melt spinning or mechanical alloying. In this work, the method using exothermic reactions between compressed metallic powders called SHS (Self-propagating High-temperature Synthesis was tested. The microstructure and phase composition of the product was described in dependence on cooling regime from the reaction temperature. Thermal stability of prepared Al-Cu-Fe quasicrystals was studied by annealing at the temperatures of 300 and 500 °C.

  14. Chemical probes of metal cluster structure--Fe, Co, Ni, and Cu

    International Nuclear Information System (INIS)

    Parks, E.K.; Zhu, L.; Ho, J.; Riley, S.J.

    1992-01-01

    Chemical reactivity is one of the few methods currently available for investigating the geometrical structure of isolated transition metal clusters. In this paper we summarize what is currently known about the structures of clusters of four transition metals, Fe, Co, Ni, and Cu, in the size range from 13 to 180 atoms. Chemical probes used to determine structural information include reactions with H 2 (D 2 ), H 2 0, NH 3 and N 2 . Measurements at both low coverage and at saturation are discussed

  15. THERMAL STABILITY OF Al-Cu-Fe QUASICRYSTALS PREPARED BY SHS METHOD

    Directory of Open Access Journals (Sweden)

    Pavel Novák

    2013-04-01

    Full Text Available Quasicrystal-containing materials are usually prepared by rapid solidification of the melt (e.g. by melt spinning or mechanical alloying. In this work, the method using exothermic reactions between compressed metallic powders called SHS (Self-propagating High-temperature Synthesis was tested. The microstructure and phase composition of the product was described in dependence on cooling regime from the reaction temperature. Thermal stability of prepared Al-Cu-Fe quasicrystals was studied by annealing at the temperatures of 300 and 500 °C.

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

    Energy Technology Data Exchange (ETDEWEB)

    Butvin, P. E-mail: fyzipbut@nic.savba.sk; Butvinova, B.; Frait, Z.; Sitek, J.; Svec, P

    2000-06-02

    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.

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

    International Nuclear Information System (INIS)

    Butvin, P.; Butvinova, B.; Frait, Z.; Sitek, J.; Svec, P.

    2000-01-01

    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

  18. Sequestration of radionuclides and heavy metals by hydroxyapatite doped with Fe, Cu and Sn

    International Nuclear Information System (INIS)

    Neidel, Linnah L.; Moore, Robert Charles; Salas, Fred; Grouios, Fotini; Holt, Kathleen Caroline; Helean, Katheryn B.

    2005-01-01

    Apatite, Ca 5 (PO 4 ) 3 (F,OH,Cl)(P6 3 /m, Z=2), is the most abundant phosphate mineral on Earth. The end-member hydroxyapatite, Ca 5 (PO 4 ) 3 OH(P2 1 /b), is the primary mineral component in bones and teeth and tends to scavenge and sequester heavy metals in the human body. Hydroxyapatite has also been shown to be effective at sequestering radionuclides and heavy metals in certain natural systems (Dybowska et al., 2004). Hydroxyapatite has been the focus of many laboratory studies and is utilized for environmental remediation of contaminated sites (Moore et al., 2002). The crystal structure of apatite tolerates a great deal of distortion caused by extensive chemical substitutions. Metal cations (e.g. REE, actinides, K, Na, Mn, Ni, Cu, Co, Zn, Sr, Ba, Pb, Cd, Fe) substitute for Ca, and oxyanions (e.g. AsO 4 3- , SO 4 2- , CO 3 2- , SiO 4 4- , CrO 4 2- ) replace PO 4 3- through a series of coupled substitutions that preserve electroneutrality. Owing to the ability of apatite to incorporate 'impurities'(including actinides) gives rise to its proposed use as a waste form for radionuclides. Recent work at Sandia National Laboratory demonstrated that hydroxyapatite has a strong affinity for U, Pu, Np, Sr and Tc reduced from pertechnetate (TcO 4 - ) by SnCl 2 (Moore et al., 2002). Based on these earlier promising results, an investigation was initiated into the use of apatite-type materials doped with aliovalent cations including Fe, Cu and Sn as Tc-scavengers. Synthetic Fe and Cu-doped hydroxyapatite samples were prepared by precipitation of Ca, from Ca-acetate, and P, from ammonium phosphate. The Fe and Cu were introduced as chlorides into the Ca-acetate solution. Stannous chloride was used as a reducing agent and was apparently incorporated into the crystal structures of the hydroxyapatite samples in small, as yet undetermined quantities.

  19. Some aspects of thermally induced martensite in Fe-30% Ni-5% Cu alloy

    International Nuclear Information System (INIS)

    Guener, M.; Gueler, E.; Yasar, E.; Aktas, H.

    2007-01-01

    Kinetical, morphological, crystallographical and several thermal properties of thermally induced martensite in the austenite phase of Fe-30% Ni-5% Cu alloy were investigated. Scanning electron microscope (SEM), transmission electron microscope (TEM) and differential scanning calorimetry (DSC) techniques were used during study. Kinetics of the transformation was found to be as athermal type. SEM and TEM observations revealed α' (BCC) martensite formation in the austenite phase of alloy by thermal effect. These thermally induced α' martensites exhibited a thin plate-like morphology with twinnings

  20. Pile oscillator measurements of thermal absorption cross sections of Al, Mg, Fe and Cu

    International Nuclear Information System (INIS)

    Carre, J.C.; Vidal, R.

    1964-01-01

    The phase oscillation technique used at ZOE has the property of reducing of a marked factor the effect of neutron scattering by the sample. The absorption cross sections of poorly absorbing and highly scattering materials have been measured; for neutrons of 2,200 m/s, the following values are obtained: 229 ± 3 mb for Al; 64.2 ± 1.5 mb for Mg, 2.53 ± 0.03 b for Fe and 3.74 ± 0.04 b for Cu. (authors) [fr

  1. Features of Magnetorefractive Effect in a [CoFe/Cu] n Multilayer Metallic Nanostructure

    Science.gov (United States)

    Yurasov, A. N.; Telegin, A. V.; Bannikova, N. S.; Milyaev, M. A.; Sukhorukov, Yu. P.

    2018-02-01

    The features of magnetorefractive effect (MRE) in metallic multilayer film Ni48Fe12Cr40(50 Å)/[Co90Fe10(14 Å)/Cu(22 Å)]8/Cr(20 Å) nanostructures, which exhibit giant magnetoresistance at room temperature, are investigated experimentally and theoretically. We show that the MRE in these structures reaches 1.5% in an applied magnetic field of 3.5 kOe, in a broad part of the IR region, and can change sign for both transmission and reflection of light. The refraction and extinction coefficients that are calculated for the nanostructures in an external magnetic field are in good agreement with our experimental data. The deduced formulas can be applied to estimating the MRE in multilayer metallic nanostructures.

  2. Moessbauer spectroscopy in nanocrystalline Fe88Zr7B4Cu1

    International Nuclear Information System (INIS)

    Navarro, I.

    1995-01-01

    Local structural changes during the crystallization process of initially amorphous Fe 88 Zr 7 B 4 Cu 1 (at %) have been investigated by means of Moessbauer spectroscopy at room temperature. In the as-cast state, no ferromagnetic phase has been detected. The crystallization process has been found to consist of two steps. In the first step (after annealing up to 500-650 C), precipitation of α-Fe (47-59%) takes place. The remaining amorphous matrix evolves to a ferromagnetic phase, although a small fraction of non-ferromagnetic phase (5-8%) is also detected during the crystallization process. Annealing at more elevated temperatures completely crystallizes the amorphous phase and three new crystalline subspectra are found. Correlations between the soft magnetic properties and these local structural changes are also discussed. ((orig.))

  3. 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.

  4. Mechanical behaviour of Br0.5Sr0.5Co0.8Fe0.2O3-δ under uniaxial compression

    International Nuclear Information System (INIS)

    Araki, Wakako; Malzbender, Jürgen

    2013-01-01

    The present study reports on the mechanical behaviour of Br 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ under uniaxial compression at various temperatures. The stress–strain curve at room temperature shows a small but clear creep deformation, along with a hysteresis and a remnant strain, which could be related to a spin transition of cobalt. The hysteresis as well as Young’s modulus decrease with increasing temperature to 473 K, at which temperature the creep behaviour disappears. The material shows conventional high-temperature creep above 673 K

  5. Electron microscopy investigations of rapidly solidified Fe-Zr-B-Cu alloys

    International Nuclear Information System (INIS)

    Majumdar, B.; Arvindha Babu, D.; Akhtar, D.

    2010-01-01

    Rapidly solidified Fe-based nanocrystalline soft magnetic materials possess a unique combination of properties i,e high permeability, saturation and Curie temperature and very low coercivity which are otherwise not attainable in conventional soft magnetic materials. The alloys are processed by producing amorphous phase through melt spinning route followed by a partial devitrification for incorporation of nanocrystalline phase in the amorphous matrix. In this paper, detailed electron microscopic investigations of melt spun Fe-Zr-B-Cu alloys are presented. Melt spun ribbons of Fe 99-x-y Zr x BCu 1 alloys with x+y = 11 and x+y = 13 were prepared under different wheel speed conditions and then vacuum annealed for 1 h at different temperatures. The microstructure changes from completely amorphous to a cellular/dendritic bcc solid solution coexisting with the amorphous phase at intercellular/dendritic regions when Zr/B ratio or the process parameters are varied. Annealing leads to the precipitation of nanocrystalline bcc-Fe phase from both amorphous phase and already existing bcc solid solution. (author)

  6. 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

  7. Nanocrystalline (Fe{sub 60}Al{sub 40}){sub 80}Cu{sub 20} alloy prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Krifa, M.; Mhadhbi, M. [Laboratoire de Chimie Inorganique, 99/UR/12-22, FSS – Université de Sfax, B.P. 1171, Sfax 3018 (Tunisia); Escoda, L.; Güell, J.M. [Dept. de Fisica, Universitat de Girona, Campus Montilivi, 17071 Girona (Spain); Suñol, J.J., E-mail: joanjosep.sunyol@udg.edu [Dept. de Fisica, Universitat de Girona, Campus Montilivi, 17071 Girona (Spain); Llorca-Isern, N.; Artieda-Guzmán, C. [Dept. CMEM, Universitat de Barcelona, Martí Franques 1, 08028 Barcelona (Spain); Khitouni, M. [Laboratoire de Chimie Inorganique, 99/UR/12-22, FSS – Université de Sfax, B.P. 1171, Sfax 3018 (Tunisia)

    2013-03-25

    Highlights: ► Nanocrystalline Fe(Al, Cu) powdered alloy (10 nm) has been synthesized by MA. ► Decreasing the crystallite size increases coercivity and squareness ratio. ► As low crystallites size stronger hard ferromagnetic material results. -- Abstract: A nanostructured disordered Fe(Al, Cu) solid solution was obtained from prealloyed FeAl and elemental Cu powders using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. The transformation of the phase depends upon the milling time. With the increase of milling time all Cu atoms became dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe(Al, Cu) solid solution with a mean crystallite size of 10 nm. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Magnetic properties were also investigated and were related to the microstructural changes. The system showed hard magnetic behavior.

  8. Adsorption performance of CuFe{sub 2}O{sub 4}/rGO nanocomposites towards organic dye

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Mingyi, E-mail: mingyitjucu@163.com [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Li, Xichuan [School of Science, Tianjin University, Tianjin 300072 (China); Gao, Chunjuan [State Ocean Adm, Inst Tianjin Seawater Desalinat & Multipurpose Ut, Tianjin 300192 (China); Li, Xianxian [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia, E-mail: haixiaqiuls@163.com [School of Science, Tianjin University, Tianjin 300072 (China)

    2017-01-01

    A facile and efficient approach was employed to synthesize CuFe{sub 2}O{sub 4}/rGO (reduced graphene oxide) nanocomposites. The morphology, crystal structure and properties of the prepared CuFe{sub 2}O{sub 4}/rGO nanocomposites were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction and thermo-gravimetric analysis. The CuFe{sub 2}O{sub 4}/rGO nanocomposites were applied as adsorbents to study their adsorption performance for Congo red. The adsorption capacity and recyclability, adsorption dynamics and adsorption models were investigated. The results show that the CuFe{sub 2}O{sub 4}/rGO nanocomposites are efficient and recyclable adsorbents. - Highlights: • CuFe{sub 2}O{sub 4}/rGO was synthesized by a facile hydrothermal route. • As an adsorbent it showed high adsorption capacity to CR. • It was magnetically removable and has high reusability.

  9. The synthesis of Cu/Fe/Fe3O4 catalyst through the aqueous solution ball milling method assisted by high-frequency electromagnetic field

    Science.gov (United States)

    Yingzhe, Zhang; Yuxing, He; Qingdong, Qin; Fuchun, Wang; Wankun, Wang; Yongmei, Luo

    2018-06-01

    In this paper, nano-magnetic Cu/Fe/Fe3O4 catalyst was prepared by a new aqueous solution ball milling method assisted by high-frequency electromagnetic field at room temperature. The products were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), selected area electron diffraction (SAED), and vibrating sample magnetometer (VSM). Microwave induced catalytic degradation of methylene blue (MB) was carried out in the presence of Cu/Fe/Fe3O4. The concentration of methylene blue was determined by UV-Vis spectrophotometry. The solid catalyst showed high catalytic activity of degrade MB and considerable saturation magnetization, lower remanence and coercivity. It indicate that the catalyst can be effectively separated for reuse by simply applying an external magnetic field and it can greatly promote their potential industrial application to eliminate organic pollutants from waste-water. Finally, we found that it is the non-thermal effect of microwave that activated the catalytic activity of Cu/Fe/Fe3O4 to degrade MB.

  10. NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals

    International Nuclear Information System (INIS)

    Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I.

    1994-01-01

    27 Al and 63,65 Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. 27 Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from zero-field NQR spectra, a wide distribution of local electric-field gradient (EFG) tensor components and principal-axis-system orientations was found at the Al site. A model EFG calculation based on a 1/1 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of 63 Cu and 27 Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured 27 Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys

  11. Magnetic Properties Studies on Thermal Aged Fe-Cu Alloys for the Simulation of Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. K.; Kishore, M.B.; Park, D. G. [KAERI, Daejeon (Korea, Republic of); Son, De Rac. [Hannam University, Daejeon (Korea, Republic of)

    2016-05-15

    We evaluated the changes in magnetic properties due to cold rolling and thermal ageing of a Fe-1%Cu model alloy in this study. Initially, the alloy was 10% cold rolled, and isothermally aged at 400 .deg. C for 1, 10, 100 and 1000 hr. The samples were prepared at various thermal aging conditions and all the conditions were interpreted. The hysteresis loops, Magnetic Barkhausen noise (BN). The change of magnetic properties can be interpreted in terms of the domain wall motion and dislocation dynamics associated with copper rich precipitates (CRPs).The results were interpreted in terms of ageing time dependence of the precipitates evolution such as the volume fraction and size distribution. In order to evaluate the radiation embrittlement of RPV steel, A Cold rolled Fe-Cu model Alloy was prepared, The prepared samples were thermally aged by annealing at 400 .deg. C for various times, the magnetic properties of the annealed samples were measured, The Barkhausen noise and BH Loop shows a considerable trend corresponding to the Ageing time. The magnetic properties were interpreted and correlated to the CRPs formed through annealing process.

  12. Correlation between zirconium oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys

    International Nuclear Information System (INIS)

    Park, Sang Yoon; Lee, Myung Ho; Choi, Byoung Kwon; Jeong, Yong Hwan; Jung, Youn Ho

    2001-01-01

    To evaluate the correlation of Zr oxide impedance and corrosion behavior of Zr-Nb-Sn-Fe-Cu alloys, the corrosion behavior of the alloys was tested in the autoclave containing 70 ppm LiOH solution at 360 .deg. C. The characteristics of the oxide on the alloys were investigated by using the electrochemical impedance spectrosocpy (EIS) method. The corrosion resistance of the alloys was evaluated from the corrosion rate determined as a function of the concentration of Nb. The equivalent circuit of the oxide was composed on the base of the spectrum from EIS measurements on the oxide layers that had formed at pre-and post-transition regions on the curve of corrosion rate. By using the capacitance characteristics of the equivalent circuit, the thickness of impervious layer, it's electrical resistance and characteristics of space charge layer were evaluated. The corrosion characteristics of the Zr-Nb-Sn-Fe-Cu alloys were successfully explained by applying the EIS test results

  13. Ne, Ar, Fe, and Cu Auger-electron production at National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Lee, D.H.; Johnson, B.M.; Jones, K.W.; Guardala, N.A.; Price, J.L.; Stumborg, M.F.; Glass, G.A.

    1992-01-01

    Energetic K and L Auger electrons produced by focussed, filtered, broad-band synchrotron radiation have been measured at the x-ray ring of the National Synchrotron Light Source (NSLS). The x-ray beam was used to study inner-shell photoionization of Ne and Ar gas and Fe and Cu solid film targets. The Auger electrons were analyzed by means of a semi-hemispherical electrostatic electron spectrometer at the energy resolution of ∼ 3 %. The electrons were detected at both 90 degree and 0 degree with respect to the photon beam direction. Broad distributions of the inner-shell photoelectrons were also observed, reflecting the incoming photon flux distribution. The Fe and Cu K Auger electron spectra were found to be very similar to the Ar K Auger electron spectra. This was expected, since deep inner-shell Auger processes are not affected by the outer valence electrons. Above 3 keV in electron energy, there have been few previous Auger electron measurements. 2 figs., 13 refs

  14. Al-matrix composite materials reinforced by Al-Cu-Fe particles

    International Nuclear Information System (INIS)

    Bonneville, J; Laplanche, G; Joulain, A; Gauthier-Brunet, V; Dubois, S

    2010-01-01

    Al-matrix material composites were produced using hot isostatic pressing technique, starting with pure Al and icosahedral (i) Al-Cu-Fe powders. Depending on the processing temperature, the final reinforcement particles are either still of the initial i-phase or transformed into the tetragonal ω-Al0 0.70 Cu 0.20 Fe 0.10 crystalline phase. Compression tests performed in the temperature range 293K - 823K on the two types of composite, i.e. Al/i and Al/ω, indicate that the flow stress of both composites is strongly temperature dependent and exhibit distinct regimes with increasing temperature. Differences exist between the two composites, in particular in yield stress values. In the low temperature regime (T ≤ 570K), the yield stress of the Al/ω composite is nearly 75% higher than that of the Al/i composite, while for T > 570K both composites exhibit similar yield stress values. The results are interpreted in terms of load transfer contribution between the matrix and the reinforcement particles and elementary dislocation mechanisms in the Al matrix.

  15. Heat treatment of the EN AC-AlSi9Cu3(Fe alloy

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2010-04-01

    Full Text Available Silumins are widely used in automotive, aviation and shipbuilding industries; as having specific gravity nearly three times lower than specific gravity of cast iron the silumins can be characterized by high mechanical properties. Additionally, they feature good casting properties, good machinability and good thermal conductivity. i.e. properties as required for machinery components operating in high temperatures and at considerable loads. Mechanical properties of the silumins can be upgraded, implementing suitably selected heat treatment. In the paper is presented an effect of modification and heat treatment processes on mechanical properties of the EN AC-AlSi9Cu3(Fe alloy. Investigated alloy has undergone typical processes of modification and refining, and next heat treatment. Temperature range of the heat treatment operations was determined on base of curves from the ATD method. Obtained results concern registered melting and solidification curves from the ATD method and strength tests. On base of the performed tests one has determined range of the heat treatment parameters which would assure obtainment of the best possible mechanical properties of the EN AC-AlSi9Cu3(Fe alloy.

  16. Design and characterization of FeCrNiCoAlCu and FeCrNiCo(AlCu){sub 0,5} multicomponent alloys; Previsao e caracterizacao de ligas multicomponentes FeCrNiCoAlCu e FeCrNiCo(AlCu){sub 0,5}

    Energy Technology Data Exchange (ETDEWEB)

    Triveno Rios, Carlos; Artacho, Victor Falcao [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Engenharia de Materiais

    2014-07-01

    High entropy alloys using multi-element main quasi-equivalent atomic proportions and generally forms single-phase solid solution and has the ability to enhance levels of strain hardening combined with high levels of plastic deformation at room temperature. In this work two high-entropy alloys with almost similar composition were studied and the factors influencing the formation of solid solution phases (δ atomic radius difference, ΔH{sub mix} mixing enthalpy, ΔS{sub mix} mixing entropy) were evaluated. The microstructure as-cast and the compositions of phases in the two alloys were analyzed by SEM and XRD. The mechanical characterization was realized by measurements of microhardness and cold compression test. The results showed that FeCrNiCo(AlCu){sub 0,5} and FeCrNiCoAlCu alloys with δ equal to 5,7 and 4,9, respectively, form alloys with solid solutions of high entropy. However, the presence of FC and BCCC structures greatly influence the mechanical properties. (author)

  17. 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.

  18. Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Tanhong [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    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.

  19. Impact of biogenic nanoscale metals Fe, Cu, Zn and Se on reproductive LV chickens

    International Nuclear Information System (INIS)

    Nguyen, Quy Khiem; Nguyen, Van Kien; Nguyen, Khac Thinh; Nguyen, Duy Dieu; Nguyen, Hoai Chau; Tran, Xuan Tin; Nguyen, Huu Cuong; Phung, Duc Tien

    2015-01-01

    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. (paper)

  20. Study of Paramagnetic Monohydrates MeSO4.1H2O (Me = Mn2+, Co2+, Fe2+, Ni2+, Cu2+

    Directory of Open Access Journals (Sweden)

    Jelšovská Kamila

    2000-09-01

    Full Text Available Nuclear magnetic resonance (NMR of protons of crystrallization water in isomorphous paramagnetic monohydrates MeSO4.1H2O with Me = Mn2+ , Co2+ , Fe2+ , Ni2+ , Cu2+ is studied in the present paper. Several physically important parameters characterizing the studied substances were derived from the NMR spectra. In this paper we analysed the dependences of the NMR second moment M2 on the magnitude of the external magnetic field induction Br and the temperature. The proton NMR spectra in paramagnetic hydrates have an asymmetric form caused by the anisotropy of the local magnetic field acting on resonating nuclei and their second moments, M2, depend linearly on the square of the external magnetic field Br. The parameters M20 (the part of the second moment M2 which corresponds to the nuclear dipole-dipole interactions and á which characterize nuclear dipole-dipole interactions of protons and paramagnetic ions, respectively, are derived from experimentally obtained dependences of M2 vs Br2. The measurements were performed at the room temperature. Calculations were realized using the approximation where two nearest neighbour ions Me2+ to each water molecule are considered. The temperature dependence of the second moment, which was realised in the temperature range 123-313 K, was more informative than the field one. Besides the individual dependences M2(T measured at fr1 and fr2 we analysed the temperature dependence of the difference ∆M2(T. Beside the second moment M20 the Curie-Weiss constant è and the magnetic moment µi of paramagnetic ions were determined from the temperature dependences. The parameters è and M20 were determined directly from the experimental data. Some knowledge on the crystalline structure for the studied substance was required for the calculation of the magnetic moment µi. By means of the classification of substances according to the Curie-Weiss parameter, the negative value of the temperature parameter è for all studied

  1. Robust and Selective Switching of an FeIII Spin-Crossover Compound on Cu2N/Cu(100) with Memristance Behavior.

    Science.gov (United States)

    Jasper-Toennies, Torben; Gruber, Manuel; Karan, Sujoy; Jacob, Hanne; Tuczek, Felix; Berndt, Richard

    2017-11-08

    The switching between two spin states makes spin-crossover molecules on surfaces very attractive for potential applications in molecular spintronics. Using scanning tunneling microscopy, the successful deposition of [Fe(pap) 2 ] + (pap = N-2-pyridylmethylidene-2-hydroxyphenylaminato) molecules on Cu 2 N/Cu(100) surface is evidenced. The deposited Fe III spin-crossover compound is controllably switched between three different states, each of them exhibiting a characteristic tunneling conductance. The conductance is therefore employed to readily read the state of the molecules. A comparison of the experimental data with the results of density functional theory calculations reveals that all Fe(pap) 2 molecules are initially in their high-spin state. The two other states are compatible with the low-spin state of the molecule but differ with respect to their coupling to the substrate. As a proof of concept, the reversible and selective nature of the switching is used to build a two-molecule memory.

  2. Synthesis and Characterization of High-Entropy Alloy AlFeCoNiCuCr by Laser Cladding

    Directory of Open Access Journals (Sweden)

    Xiaoyang Ye

    2011-01-01

    Full Text Available High-entropy alloys have been recently found to have novel microstructures and unique properties. In this study, a novel AlFeCoNiCuCr high-entropy alloy was prepared by laser cladding. The microstructure, chemical composition, and constituent phases of the synthesized alloy were characterized by SEM, EDS, XRD, and TEM, respectively. High-temperature hardness was also evaluated. Experimental results demonstrate that the AlFeCoNiCuCr clad layer is composed of only BCC and FCC phases. The clad layers exhibit higher hardness at higher Al atomic content. The AlFeCoNiCuCr clad layer exhibits increased hardness at temperature between 400–700°C.

  3. Magnetic Excitations in Weakly Coupled Spin Dimers and Chains Material Cu2Fe2Ge4O13

    International Nuclear Information System (INIS)

    Masuda, Takatsugu; Zheludev, Andrey I.; Sales, Brian C.; Imai, S.; Uchinokura, K.; Park, S.

    2005-01-01

    Magnetic excitations in a weakly coupled spin dimers and chains compound Cu 2 Fe 2 Ge 4 O 13 are measured by inelastic neutron scattering. Both structure factors and dipsersion of low-energy excitations up to 10 meV energy transfer are well described by a semiclassical spin wave theory involving interacting Fe 3+ (S=5/2) chains. Additional dispersionsless excitations are observed at higher energies, at ℎω=24 meV, and associated with singlet-triplet transitions within Cu 2+ dimers. Both types of excitations can be understood by treating weak interactions between the Cu 2+ and Fe 3+ subsystems at the level of the mean-field random phase approximation. However, this simple model fails to account for the measured temperature dependence of the 24 meV mode.

  4. Preparation of Cu-Fe-Al-O nanosheets and their catalytic application in methanol steam reforming for hydrogen production

    Science.gov (United States)

    Wang, Leilei; Zhang, Fan; Miao, Dinghao; Zhang, Lei; Ren, Tiezhen; Hui, Xidong; He, Zhanbing

    2017-03-01

    Candidates of precious metal catalysts, prepared in a facile and environmental way and showing high catalytic performances at low temperatures, are always highly desired by industry. In this work, large-scale Cu-Fe-Al-O nanosheets were synthesized by facile dealloying of Al-Cu-Fe alloys in NaOH solution. The composition, microscopic morphology, and crystal structure were respectively investigated using wavelength-dispersive x-ray spectroscopy with an electron probe microanalyzer, scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. Furthermore, we found that the 2D Cu-Fe-Al-O nanosheets gave excellent catalytic performances in hydrogen production by methanol steam reforming at relatively low temperatures, e.g. 513 K.

  5. 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.

  6. Structural disorder and its effect on the superconducting transition temperature in the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br

    International Nuclear Information System (INIS)

    Su, X.; Zuo, F.; Schlueter, J.A.; Kelly, M.E.; Williams, J.M.

    1998-01-01

    In this paper, we report direct evidence of a structural transition in the organic superconductor κ-(BEDT-TTF) 2 Cu[N(CN) 2 ]Br near 80 K and the effect of disorder on the superconducting transition temperature. By cooling the sample from above 80 K, the interlayer magnetoresistance displays a bumplike feature, which increases sharply with increasing cooling rate. The rapidly cooled sample has a much larger resistivity and a lower transition temperature, which decreases linearly with increasing resistivity near the transition temperature. We propose that rapid cooling quenches the sample into a disordered state. Localized moments in the disordered state reduce the superconducting transition temperature. copyright 1998 The American Physical Society

  7. Crystallographic and magnetic properties of (C6D11ND3)CuBr3 and (Zn1-xMnx)3As2

    International Nuclear Information System (INIS)

    Vries, G.C. de.

    1989-08-01

    The investigations described concern the crystallographic and magnetic properties of the quasi one-dimensional (1d) ferromagnetic system (C 6 D 11 ND 3 )CuBr 3 (or CHAB) and the II-V type diluted magnetic semiconductor (Zn 1 - x Mn x ) 3 As 2 (or ZMA). Both compounds have been studied with various neutron scattering techniques. The crystallographic properties of CHAB and ZMA have been investigated by neutron diffraction. These diffraction experiments were carried out at the High Flux Reactor (HFR) at Petten, Netherlands. For the investigation of the static and dynamic magnetic properties of CHAB neutron scattering experiments were performed in Petten as well as other European reactor institutes. These investigations comprise a study of the 3d long-rate order and the 1d correlations of the magnetic moments, and a study of the behaviour of the linear spin-wave excitations

  8. Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO₂.

    Science.gov (United States)

    Stöcker, Thomas; Exner, Jörg; Schubert, Michael; Streibl, Maximilian; Moos, Ralf

    2016-03-24

    In the field of thermoelectric energy conversion, oxide materials show promising potential due to their good stability in oxidizing environments. Hence, the influence of oxygen partial pressure during synthesis on the thermoelectric properties of Cu-Delafossites at high temperatures was investigated in this study. For these purposes, CuFeO₂ powders were synthetized using a conventional mixed-oxide technique. X-ray diffraction (XRD) studies were conducted to determine the crystal structures of the delafossites associated with the oxygen content during the synthesis. Out of these powders, films with a thickness of about 25 µm were prepared by the relatively new aerosol-deposition (AD) coating technique. It is based on a room temperature impact consolidation process (RTIC) to deposit dense solid films of ceramic materials on various substrates without using a high-temperature step during the coating process. On these dense CuFeO₂ films deposited on alumina substrates with electrode structures, the Seebeck coefficient and the electrical conductivity were measured as a function of temperature and oxygen partial pressure. We compared the thermoelectric properties of both standard processed and aerosol deposited CuFeO₂ up to 900 °C and investigated the influence of oxygen partial pressure on the electrical conductivity, on the Seebeck coefficient and on the high temperature stability of CuFeO₂. These studies may not only help to improve the thermoelectric material in the high-temperature case, but may also serve as an initial basis to establish a defect chemical model.

  9. An insight into the metal coordination and spectroscopic properties of artistic Fe and Fe/Cu logwood inks

    Science.gov (United States)

    Bronzato, Maddalena; Zoleo, Alfonso; Biondi, Barbara; Centeno, Silvia A.

    2016-01-01

    Fe- and Fe/Cu-based logwood inks were synthesized following recipes in nineteenth and early twentieth century manuals and were characterized by EPR, ESI-MS, FTIR, and Raman spectroscopies. This multi-technique approach allowed us to shed light on the structures of the complexes responsible for the inks' colors and to obtain vibrational signatures that can be used to identify the different inks in works of art and in historic documents. Information on the nature and chemical properties of the complexes formed between a dye and a mordant is important as these determine, at least in part, their lightfastness. EPR permitted to determine the coordination environment of the metallic ions. The results of the ESI-MS analysis demonstrated, for the first time, the breakdown of the hematein molecule during the ink preparation, and that the colorants are formed by the complexation of the metallic ions by hematein breakdown products, mainly catechol and/or bicyclic compounds. The FTIR spectra obtained were found to be dominated by bands due to the binding medium and sulfates used as reagents. The Raman analysis showed that the characteristic features for the different inks studied depend on the historic recipe used, attesting to the challenges that their identification and characterization in works of art present. In the Raman spectra of the inks applied on paper, broadening of bands in the 750-400 cm- 1 range are observed when compared to the spectra of the inks' powders, possibly due to the interaction of the compounds with the cellulose in the substrate.

  10. Anisotropy migration of self-point defects in dislocation stress fields in BCC Fe and FCC Cu

    International Nuclear Information System (INIS)

    Sivak, A.B.; Chernov, V.M.; Dubasova, N.A.; Romanov, V.A.

    2007-01-01

    Spatial dependence of the interaction energies of self-point defects (vacancies and self interstitial atoms in stable, metastable and saddle point configurations) with edge dislocations in slip systems {1 1 0} and {1 0 0} in BCC Fe and {1 1 1} in FCC Cu was calculated using the anisotropic theory of elasticity and molecular statics (hybrid method). The migration pathways of vacancies and SIA ( dumbbell in Fe and dumbbell in Cu) along which the migration of the defects with the lowest energy barriers were defined in the presence of the dislocation stress fields. These pathways are significantly different in the stress fields of dislocations

  11. Thermodynamic properties of antiferromagnetic ordered states of π -d interacting systems of κ -(BETS) 2Fe X4(X =Br ,Cl )

    Science.gov (United States)

    Fukuoka, Shuhei; Yamashita, Satoshi; Nakazawa, Yasuhiro; Yamamoto, Takashi; Fujiwara, Hideki; Shirahata, Takashi; Takahashi, Kazuko

    2016-06-01

    The results are presented for systematic heat capacity measurements of π-d interacting systems of κ -(BETS) 2Fe Br4 and κ -(BETS) 2FeC l4 [BETS = bis(ethylenedithio)tetraselenafulvalene] performed under in-plane magnetic fields. We observed sharp thermal anomalies at 2.47 K for κ -(BETS) 2FeB r4 and at 0.47 K for κ -(BETS) 2FeC l4 at 0 T that are associated with antiferromagnetic transitions of the 3 d electrons in the anion layers. From analyses of the magnetic heat capacity data, we indicate that the two compounds show unconventional thermodynamic behaviors inherent in the π-d interacting layered system. In the case of κ -(BETS) 2FeB r4 , a small hump structure was observed in the magnetic heat capacity below the transition temperature when a magnetic field was applied parallel to the a axis. In the case of κ -(BETS) 2FeC l4 , a similar hump structure was observed at 0 T that remained in the data with magnetic fields applied parallel to the a axis. We demonstrate that the temperature dependencies of the magnetic heat capacities scale well by normalizing the temperatures with dominant one-dimensional direct interactions (Jdd/kB) of each compound. The field dependencies of the transition temperatures and the hump structures are elucidated in one simple magnetic field vs temperature (H -T ) phase diagram. These results indicate that the thermodynamic features of both κ-type BETS salts are essentially equivalent, and the observed hump structures are derived from the one-dimensional Jdd interaction characters, which are still influential for magnetic features even in the long-range magnetic ordered states.

  12. Structure and magnetism of ultrathin Co and Fe films epitaxially grown on Pd/Cu(0 0 1)

    International Nuclear Information System (INIS)

    Lu, Y.F.; Przybylski, M.; Yan, L.; Barthel, J.; Meyerheim, H.L.; Kirschner, J.

    2005-01-01

    A contribution originating from the Co/Pd and Fe/Pd interfaces to the magneto-optical Kerr effect (MOKE) rotation is analyzed for Co and/or Fe films grown on a Pd-buffer-monolayer on Cu(0 0 1). A clear increase of the MOKE signal in comparison to the Co(Fe) films grown directly on Cu(0 0 1) is detected. An interpretation is supported by similar observations for Co films grown on Pd(1 1 0) and Pd(0 0 1). In particular, the sign reversal of the Kerr loops with increasing thickness of the Co(Fe) films is discussed. Magneto-optical effects are separated from the real magnetization and its dependence on the film thickness

  13. Importance of halogen···halogen contacts for the structural and magnetic properties of CuX2(pyrazine-N,N′-dioxide)(H2O)2 (X = Cl and Br).

    Science.gov (United States)

    Schlueter, John A; Park, Hyunsoo; Halder, Gregory J; Armand, William R; Dunmars, Cortney; Chapman, Karena W; Manson, Jamie L; Singleton, John; McDonald, Ross; Plonczak, Alex; Kang, Jinhee; Lee, Chaghoon; Whangbo, Myung-Hwan; Lancaster, Tom; Steele, Andrew J; Franke, Isabel; Wright, Jack D; Blundell, Stephen J; Pratt, Francis L; deGeorge, Joseph; Turnbull, Mark M; Landee, Christopher P

    2012-02-20

    The structural and magnetic properties of the newly crystallized CuX(2)(pyzO)(H(2)O)(2) (X = Cl, Br; pyzO = pyrazine-N,N'-dioxide) coordination polymers are reported. These isostructural compounds crystallize in the monoclinic space group C2/c with, at 150 K, a = 17.0515(7) Å, b = 5.5560(2) Å, c = 10.4254(5) Å, β = 115.400(2)°, and V = 892.21(7) Å(3) for X = Cl and a = 17.3457(8) Å, b = 5.6766(3) Å, c = 10.6979(5) Å, β = 115.593(2)°, and V = 950.01(8) Å(3) for X = Br. Their crystal structure is characterized by one-dimensional chains of Cu(2+) ions linked through bidentate pyzO ligands. These chains are joined together through OH···O hydrogen bonds between the water ligands and pyzO oxygen atoms and Cu-X···X-Cu contacts. Bulk magnetic susceptibility measurements at ambient pressure show a broad maximum at 7 (Cl) and 28 K (Br) that is indicative of short-range magnetic correlations. The dominant spin exchange is the Cu-X···X-Cu supersuperexchange because the magnetic orbital of the Cu(2+) ion is contained in the CuX(2)(H(2)O)(2) plane and the X···X contact distances are short. The magnetic data were fitted to a Heisenberg 1D uniform antiferromagnetic chain model with J(1D)/k(B) = -11.1(1) (Cl) and -45.9(1) K (Br). Magnetization saturates at fields of 16.1(3) (Cl) and 66.7(5) T (Br), from which J(1D) is determined to be -11.5(2) (Cl) and -46.4(5) K (Br). For the Br analog the pressure dependence of the magnetic susceptibility indicates a gradual increase in the magnitude of J(1D)/k(B) up to -51.2 K at 0.84 GPa, suggesting a shortening of the Br···Br contact distance under pressure. At higher pressure X-ray powder diffraction data indicates a structural phase transition at ∼3.5 GPa. Muon-spin relaxation measurements indicate that CuCl(2)(pyzO)(H(2)O)(2) is magnetically ordered with T(N) = 1.06(1) K, while the signature for long-range magnetic order in CuBr(2)(pyzO)(H(2)O)(2) was much less definitive down to 0.26 K. The results for the Cu

  14. Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

    Science.gov (United States)

    Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.

    2016-12-01

    Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.

  15. Novel Amorphous Fe-Zr-Si(Cu) Boron-free Alloys

    Science.gov (United States)

    Kopcewicz, M.; Grabias, A.; Latuch, J.; Kowalczyk, M.

    2010-07-01

    Novel amorphous Fe80(ZrxSi20-x-y)Cuy boron-free alloys, in which boron was completely replaced by silicon as a glass forming element, have been prepared in the form of ribbons by a melt quenching technique. The X-ray diffraction and Mössbauer spectroscopy measurements revealed that the as-quenched ribbons with the composition of x = 6-10 at. % and y = 0, 1 at. % are predominantly amorphous. DSC measurements allowed the estimation of the crystallization temperatures of the amorphous alloys. The soft magnetic properties have been studied by the specialized rf-Mössbauer technique in which the spectra were recorded during an exposure of the samples to the rf field of 0 to 20 Oe at 61.8 MHz. Since the rf-collapse effect observed is very sensitive to the local anisotropy fields it was possible to evaluate the soft magnetic properties of amorphous alloys studied. The rf-Mössbauer studies were accompanied by the conventional measurements of the quasi-static hysteresis loops from which the magnetization and coercive fields were estimated. It was found that amorphous Fe-Zr-Si(Cu) alloys are magnetically very soft, comparable with those of the conventional amorphous B-containing Fe-based alloys.

  16. Pyridoxal derived chemosensor for chromogenic sensing of Cu2+ and fluorogenic sensing of Fe3+ in semi-aqueous medium

    International Nuclear Information System (INIS)

    Sahoo, Suban K.; Sharma, Darshna; Moirangthem, Anuradha; Kuba, Aman; Thomas, Rini; Kumar, Rajender; Kuwar, Anil; Choi, Heung-Jin; Basu, Anupam

    2016-01-01

    An easy-to-prepare chemosensor L was developed by condensation of pyridoxal with 1,8-diaminonaphthalene. In DMSO:H 2 O (1:1, v/v), sensor L displayed a highly selective and sensitive response towards Cu 2+ via perceptible color and UV–vis absorbance changes among the other tested metal ions. However, the fluorescence of L is selectively quenched in the presence of both Fe 3+ and Cu 2+ . With a micromolar detection limit and non-interference from other co-existing metal ions, this sensor can be applied over a wide pH range for the detection of Fe 3+ and Cu 2+ . In addition, the cytotoxicity and fluorescence changes of L within live HeLa cells were examined in the absence and presence of Cu 2+ . - Highlights: • A new noncytotoxic chemosensor derived from vitamin B 6 cofactor was introduced. • Sensor showed colorimetric sensing ability towards Cu 2+ . • Sensor showed fluorescent turn-off sensing ability towards Fe 3+ and Cu 2+ . • Detection limit was better than the prescribed permissible limit.

  17. 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

  18. Production of sulfate radical from peroxymonosulfate induced by a magnetically separable CuFe2O4 spinel in water: Efficiency, stability, and mechanism

    KAUST Repository

    Zhang, Tao; Zhu, Haibo; Croue, Jean-Philippe

    2013-01-01

    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

  19. 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.

  20. Mechanisms controlling Cu, Fe, Mn, and Co profiles in peat of the Filson Creek Fen, northeastern Minnesota

    Science.gov (United States)

    Walton-Day, K.; Filipek, L.H.; Papp, C.S.E.

    1990-01-01

    Filson Creek Fen, located in northeastern Minnesota, overlies a Cu-Ni sulfide deposit. A site in the fen was studied to evaluate the hydrogeochemical mechanisms governing the development of Fe, Mn, Co, and Cu profiles in the peat. At the study site, surface peat approximately 1 m thick is separated from the underlying mineralized bedrock by a 6-12 m thickness of lake and glaciofluvial sediments and till. Concentrations of Fe, Mn, Co, and Cu in peat and major elements in pore water delineate a shallow, relatively oxidized, Cu-rich zone overlying a deeper, reduced, Fe-, Mn-, and Co-rich zone within the peat. Sequential metal extractions from peat samples reveal that 40-55% of the Cu in the shallow zone is associated with organic material, whereas the remaining Cu is distributed between iron-oxide, sulfide, and residual fractions. Sixty to seventy percent of the Fe, Mn, and Co concentrated in the deeper zone occur in the residual phase. The metal profiles and associations probably result from non-steady-state input of metals and detritus into the fen during formation of the peat column. The enrichment of organic-associated Cu in the upper, oxidized zone represents a combination of Cu transported into the fen with detrital plant fragments and soluble Cu, derived from weathering of outcrop and subcrop of the mineral deposit, transported into the fen, and fixed onto organic matter in the peat. The variable stratigraphy of the peat indicates that weathering processes and surface vegetation have changed through time in the fen. The Fe, Mn, and Co maxima at the base of the peat are associated with a maximum in detrital matter content of the peat resulting from a transition between the underlying inorganic sedimentary environment to an organic sedimentary environment. The chemistry of sediments and ground water collected beneath the peat indicate that mobilization of metals from sulfide minerals in the buried mineral deposit or glacial deposits is minimal. Therefore, the

  1. Diethylenetriamine/diamines/copper (II complexes [Cu(dien(NN]Br2: Synthesis, solvatochromism, thermal, electrochemistry, single crystal, Hirshfeld surface analysis and antibacterial activity

    Directory of Open Access Journals (Sweden)

    Fatima Abu Saleemh

    2017-09-01

    Full Text Available Two dicationic water soluble mixed triamine/diamine copper (II complexes, of general formula [Cu(dienNN]Br2 (1–2 [dien = diethelenetriamine and NN is en = ethylenediamine or Me4en = N,N′,N,N′-tetramethylethylenediamine] were prepared under ultrasonic mode with a relatively high yield. These complexes were characterized by elemental microanalysis, UV visible IR spectroscopy, and thermal and electrochemical techniques. In addition, complex 2 structure was solved by X-ray single crystal and Hirshfeld surface analysis. The complex exhibits a distorted square pyramidal coordination environment around Cu(II centre. The solvatochromism of the desired complexes was investigated in water and other suitable organic solvents. The results show that the Guttmann’s DN parameter values of the solvents have mainly contributed to the shift of the d–d absorption band towards the linear increase in the wavelength of the absorption maxima of the complexes. The complex 1 showed higher antibacterial activity against the studied microorganisms compared to complex 2. Both complexes revealed promising antibacterial activities.

  2. Magnetic properties and EXAFS study of nanocrystalline Fe2Mn0.5Cu0.5Al synthesized using mechanical alloying technique

    International Nuclear Information System (INIS)

    Nanto, Dwi; Yang, Dong-Seok; Yu, Seong-Cho

    2014-01-01

    Nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al has been synthesized by the mechanical alloying technique and studied as a function of milling time. Alloy nature of Fe 2 Mn 0.5 Cu 0.5 Al was observed in a sample milled for 96 h. The magnetic saturation is 4.0 μ B /f.u., which coincidently follows Slater–Pauling rule at 5 K. Nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al has enhanced saturate magnetization compared to any other fabrication of Fe 2 MnAl reported. Cu element plays an important role in site competes with other elements and may result in the enhancement of saturate magnetization. In accordance to the magnetic results and EXAFS pattern, it was revealed that the dynamics of magnetic properties were confirmed as structural changes of nanocrystalline Fe 2 Mn 0.5 Cu 0.5 Al

  3. TEM study on a new Zr-(Fe, Cu) phase in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cu alloy

    Science.gov (United States)

    Liu, Yushun; Qiu, Risheng; Luan, Baifeng; Hao, Longlong; Tan, Xinu; Tao, Boran; Zhao, Yifan; Li, Feitao; Liu, Qing

    2018-06-01

    A new Zr-(Fe, Cu) phase was found in furnace-cooled Zr-1.0Sn-0.3Nb-0.3Fe- 0.1Cu alloy and alloys aged at 580 °C for 10min, 2 h and 10 h. Electron diffraction experiment shows the crystal structure of this phase to be body-centered tetragonal with unit cell dimensions determined to be a = b = 6.49 Å, c = 5.37 Å. Its possible space groups have been discussed and the reason accounting for its formation is believed to be the addition of Cu according to the atom-level images. In addition, no crystal structural or chemical composition changes were observed throughout the aging process.

  4. Initial permeability and vickers hardness of thermally aged FeCu alloy

    International Nuclear Information System (INIS)

    Kikuchi, H.; Onuki, T.; Kamada, Y.; Ara, K.; Kobayashi, S.; Takahashi, S.

    2007-01-01

    The initial permeability obtained from small AC field excitation is a more useful parameter for nondestructive evaluation (NDE) of ferromagnetic materials than one obtained from a major hysteresis loop from the viewpoints of electricity consumption and real-time measurements. In this paper, in order to study the possibility of applying magnetic methods to pressure vessel surveillance at nuclear power plants, permeability of the thermally aged Fe-Cu specimens were evaluated using impedance measurements and the hardness of those specimens was also evaluated. The Vickers hardness increases as aging time increases. The permeability of the cold-rolled specimen decreases with thermal aging. On the other hand, the permeability of as-received specimens increased at first then decreases as thermal aging goes

  5. Cu-Fe welding techniques by electromagnetic and electron beam welding processes

    International Nuclear Information System (INIS)

    Kumar, Satendra; Saroj, P.C.; Kulkarni, M.R.; Sharma, A.; Rajawat, R.K.; Saha, T.K.

    2015-01-01

    Electromagnetic welding being a solid state welding process has been found suitable for welding Copper and Iron which are conventionally very tricky. Owing to good electrical conductivity of both copper and iron, they are best suited combination for EM welding. For the experimental conditions presented above, 1.0 mm wall thickness of Cu tube was lap welded to Fe disc. A heavy duty four disc stainless steel coil was used for electromagnetic welding of samples. MSLD of the welded samples indicated leak proof joints. Metallographic examination of the welds also revealed defect free interfaces. Electron beam welding is also a non-conventional welding process used for joining dissimilar materials. Autogenous welding of the above specimen was carried out by EBW method for the sake of comparison. A characterization analysis of the above mentioned joining processes will be discussed in the paper. (author)

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

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2012-01-01

    Full Text Available 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 1 473 K and with gas fl ow 5,55•10-6, 6,94•10-6, 8,33•10-6, 9,72•10-6 m3•s-1.

  7. 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.

  8. L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu

    International Nuclear Information System (INIS)

    Del Grande, N.K.

    1989-01-01

    Synchrotron radiation measurements of near-threshold and broad-range (400--1500 eV) absolute photoabsorption cross sections were made for five transition metals with ±10% overall uncertainties. Fine structure details of 2p-3d autoionizing resonances are shown with better than 1.0 eV resolution for solid metals: Ti, V, Cr, Fe, Ni, and Cu. Fine structure similar to what we measured can be produced using a multi-configuration Dirac Fock (MCDF) model if a statistical distribution is assumed for the initial atomic states. Calculations were performed in intermediate coupling with configuration interactions by Mau H. Chen. The results are compared with other experimental work and theoretical methodologies. 18 refs., 7 figs

  9. 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.

  10. Characterisation of the antiferromagnetic transition of Cu2FeSnS4, the synthetic analogue of stannite

    Science.gov (United States)

    Caneschi, A.; Cipriani, C.; di Benedetto, F.; Sessoli, R.

    2003-04-01

    Magnetisation measurements between 260 and 1.9K were performed on the synthetic analogue of stannite, Cu_2FeSnS_4, tetragonal Ioverline{4}2m. Fe(II) ions, in the high spin S=2 configuration for tetrahedral coordination, are responsible for the high temperature paramagnetism. In agreement with Bernardini et al. (2000), an antiferromagnetic transition was observed, lowering temperature below 8K. Refined measurements evidenced a T_N=6.1K for the Néel temperature. In spite of a small difference, observed in the behaviour between the zero-field cooled and the field cooled curves, which suggests the possible presence of a spin-glass phase, the AC measurements did not provide evidence of dependence of the magnetic susceptibility on frequency, as expected in spin-glass systems. On the basis of the experimental data, in agreement with the existent literature (Fries et al., 1997), a collinear antiferromagnetic structure should be preferred. The Fe ions, in fact, are distributed in two sublattices obtained by magnetic differentiation of the symmetry equivalent (0,0,0) and (frac{1}{2}frac{1}{2}frac{1}{2}) Fe positions (wyckoff: 2a). The low value for the Nèel temperature, as compared e.g. to the room-temperature antiferromagnet chalcopyrite (CuFeS_2), very close in composition and structure to stannite, is to be related to the increased distance between the Fe ions (˜6.6Å). This weak interaction is not detected in natural samples, where diamagnetic Zn(II) replace paramagnetic Fe(II), thus increasing the mean Fe-Fe distance. Fries, T., Shapira, Y., Palacio, F., Moròn, M.C., McIntyre, G.J., Kershaw, R., Wold, A. and McNiff, E.J. Jr. (1997): Mangetic ordering of the antiferromagnet Cu_2MnSnS_4 from magnetisation and neutron-scattering measurements. Phys. Rev. B, 6(9), 5424-5431 Bernardini, G.P., Borrini, D., Caneschi, A. Di Benedetto, F., Gatteschi, D., Ristori, S. and Romanelli, M. (2000): EPR and SQUID magnetometry study of Cu_2FeSnS_4 (stannite) and Cu_2ZnSnS_4 (kesterite

  11. Fabrication of mesoporous iron (Fe) doped copper sulfide (CuS) nanocomposite in the presence of a cationic surfactant via mild hydrothermal method for supercapacitors

    Science.gov (United States)

    Brown, J. William; Ramesh, P. S.; Geetha, D.

    2018-02-01

    We report fabrication of mesoporous Fe doped CuS nanocomposites with uniform mesoporous spherical structures via a mild hydrothermal method employing copper nitrate trihydrate (Cu (NO3).3H2O), Thiourea (Tu,Sc(NH2)2 and Iron tri nitrate (Fe(No3)3) as initial materials with cationic surfactant cetyltrimethylamoniame bromide (CTAB) as stabilizer/size controller and Ethylene glycol as solvent at 130 °C temperature. The products were characterized by XRD, SEM/EDX, TEM, FTIR and UV analysis. X-ray diffraction (XRD) spectra confirmed the Fe doped CuS nanocomposites which are crystalline in nature. EDX and XRD pattern confirmed that the product is hexagonal CuS phase. Fe doped spherical structure of CuS with grain size of 21 nm was confirmed by XRD pattern. Fe doping was identified by energy dispersive spectrometry (EDS). The Fourier-transform infrared (FTIR) spectroscopy results revealed the occurrence of active functional groups required for the reduction of copper ions. Studies showed that after a definite time relining on the chosen copper source, the obtained Fe-CuS nanocomposite shows a tendency towards self-assembly and creating mesoporous like nano and submicro structures by TEM/SAED. The achievable mechanism of producing this nanocomposite was primarily discussed. The electrochemical study confirms the pseudocapacitive nature of the CuS and Fe-CuS electrodes. The CuS and Fe-CuS electrode shows a specific capacitance of about 328.26 and 516.39 Fg-1 at a scan rate of 5 mVs-1. As the electrode in a supercapacitor, the mesoporous nanostructured Fe-CuS shows excellent capacitance characteristics.

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

    Science.gov (United States)

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

    2002-06-01

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

  13. A Hybrid Mineral Battery: Energy Storage and Dissolution Behavior of CuFeS2 in a Fixed Bed Flow Cell.

    Science.gov (United States)

    Deen, Kashif Mairaj; Asselin, Edouard

    2018-05-09

    The development of a hybrid system capable of storing energy and the additional benefit of Cu extraction is discussed in this work. A fixed bed flow cell (FBFC) was used in which a composite negative electrode containing CuFeS 2 (80 wt %) and carbon black (20 wt %) in graphite felt was separated from a positive (graphite felt) electrode by a proton-exchange membrane. The anolyte (0.2 m H 2 SO 4 ) and catholyte (0.5 m Fe 2+ in 0.2 m H 2 SO 4 with or without 0.1 m Cu 2+ ) were circulated in the cell. The electrochemical activity of the Fe 2+ /Fe 3+ redox couple over graphite felt significantly improved after the addition of Cu 2+ in the catholyte. Ultimately, in the CuFeS 2 ∥Fe 2+ /Cu 2+ (CFeCu) FBFC system, the specific capacity increased continuously to 26.4 mAh g -1 in 500 galvanostatic charge-discharge (GCD) cycles, compared to the CuFeS 2 ∥Fe 2+ (CFe) system (13.9 mAh g -1 ). Interestingly, the specific discharge energy gradually increased to 3.6 Wh kg -1 in 500 GCD cycles for the CFeCu system compared to 3.29 Wh kg -1 for the CFe system in 150 cycles. In addition to energy storage, 10.75 % Cu was also extracted from the mineral, which is an important feature of the CFeCu system as it would allow Cu extraction and recovery through hydrometallurgical methods. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Preparation And Characterization of Cu-Fe/ TiO2 Photocatalyst for Visible Light Deep Desulfurization

    International Nuclear Information System (INIS)

    Hayyiratul Fatimah Mohd Zaid; Kait, C.F.; Mohamed Ibrahim Abdul Mutalib

    2016-01-01

    A photooxidative system for deep desulfurization of model diesel fuel was explored. Nanoparticles of anatase titania (TiO 2 ) were synthesized via sol-gel hydrothermal method. The TiO 2 was further modified with bimetallic Cu-Fe using wet-impregnation method followed by calcination process in order to extend the activity region of the photocatalyst to visible-light. A series of bimetallic 2.2 wt % Cu-Fe/ TiO 2 photocatalysts with different Cu:Fe mass compositions were characterized for their physical, chemical and optical properties using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance UV-visible spectroscopy (DR-UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmet-Teller (BET) surface area analysis. The performance of the photocatalysts was evaluated for photooxidation of dibenzothiophene (DBT) as the sulfur species from model oil in the presence of hydrogen peroxide, H 2 O 2 under 500 W visible light illumination. The highest sulfur conversion of 82.36 % was observed for photocatalyst with 10:1Cu:Fe mass composition. (author)

  15. Variability of Mn, Fe, Ni, Cu and Co in manganese nodules from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Jauhari, P.

    clays which contain higher Fe and Co. Clustering of analysed shows that Ni and Cu are geochemically associated with Mn, and Co with in both sediment types. However, the degree of correlation between all the elements is higher in the nodules from red clay...

  16. Quasicrystalline phase formation in the mechanically alloyed Al{sub 70}Cu{sub 20}Fe{sub 10}

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, S. N. de, E-mail: snm@dfi.uem.br; Cadore, S.; Pereira, H. A.; Santos, I. A.; Colucci, C. C.; Paesano, A. [Universidade Estadual de Maringa, Departamento de Fisica (Brazil)

    2010-01-15

    In the present work, the formation of the Al{sub 70}Cu{sub 20}Fe{sub 10} icosahedral phase by mechanical alloying the elemental powders in a high-energy planetary mill was investigated by X-ray diffraction and Moessbauer spectroscopy. It was verified that the sample milled for 80 h produces an icosahedral phase besides Al(Cu, Fe) solid solution ({beta}-phase) and Al{sub 2}Cu intermetallic phase. The Moessbauer spectrum for this sample was fitted with a distribution of quadrupole splitting, a doublet and a sextet, revealing the presence of the icosahedral phase, {beta}-phase and {alpha}-Fe, respectively. This compound is not a good hydrogen storage. The results of the X-ray diffraction and Moessbauer spectroscopy of the sample milled for 40 h and annealed at 623 deg. C for 16 h shows essentially single i-phase and tetragonal Al{sub 7}Cu{sub 2} Fe phase.

  17. Generation of covariance files for the isotopes of Cr, Fe, Ni, Cu, and Pb in ENDF/B-VI

    International Nuclear Information System (INIS)

    Hetrick, D.M.; Larson, D.C.; Fu, C.Y.

    1991-02-01

    The considerations that governed the development of the uncertainty files for the isotopes of Cr, Fe, Ni, Cu, and Pb in ENDF/B-VI are summarized. Four different approaches were used in providing the covariance information. Some examples are given which show the standard deviations as a function of incident energy and the corresponding correlation matrices. 11 refs., 5 tabs

  18. 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...

  19. Low energy Cu clusters slow deposition on a Fe (001) surface investigated by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shixu [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Laboratory of Advanced Nuclear Materials, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Gong, Hengfeng [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Division of Nuclear Materials Science and Engineering, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Chen, Xuanzhi [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Li, Gongping, E-mail: ligp@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, Zhiguang, E-mail: zhgwang@impcas.ac.cn [Laboratory of Advanced Nuclear Materials, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-09-30

    Highlights: • We study the deposition of low energy Cu clusters on Fe (001) surface by molecular dynamics. • The interaction between low energy cluster and substrate can be divided to the landing and the thermal diffusion phases. • The phenomenon of contact epitaxy of cluster occurred. • The thermal diffusion of cluster atoms was analyzed. - Abstract: The slow deposition of low energy Cu clusters on a Fe (001) surface was investigated by molecular dynamics simulation. A many-body potential based on Finnis–Sinclair model was used to describe the interactions among atoms. Three clusters comprising of 13, 55 and 147 atoms, respectively, were deposited with incident energies ranging from 0.0 to 1.0 eV/atom at various substrate temperatures (0, 300 and 800 K). The rearrangement and the diffusion of cluster can occur, only when the cluster atoms are activated and obtained enough migration energy. The interaction between low energy cluster and substrate can be divided to the landing and the thermal diffusion phases. In the former, the migration energy originates from the latent heat of binding energy for the soft deposition regime and primarily comes from the incident energy of cluster for the energetic cluster deposition regime. In the latter, the thermal vibration would result in some cluster atoms activated again at medium and high substrate temperatures. Also, the effects of incident energy, cluster size and substrate temperature on the interaction potential energy between cluster and substrate, the final deposition morphology of cluster, the spreading index and the structure parameter of cluster are analyzed.

  20. Two-dimensional nano-lattice in Fe-Co-Ni-Al-Cu alloys

    International Nuclear Information System (INIS)

    Kalanov, M.U.; Ibragimova, E.M.; Khamraeva, R.N.; Rustamova, V.M.; Ummatov, H.D.

    2007-01-01

    Full text: The high coercive strength of the dispersionally solidified alloys on the base of Fe-Co-Ni-Al-Cu system appears as a result of the special thermomagnetic annealing, when particles of the strong magnetic phase are distinguished in non-magnetic matrix along an external magnetic field direction. The neutron studying allows one to reveal the correlation between magnetization and inclusion axes, and also existence of magnetic microcell and perfectness of the lattice. This work presents results of neutron diffraction study with a double-crystal spectrometer (0.145 nm). Plate like samples of size 18 12 4 mm 3 were cut from a single crystal of alloy UNDK35 T5 along (100) plane. Magnetic field of 6 kOe was applied perpendicular to the neutron beam. Zero-field spectrum had only random variation of the background. Under the applied magnetic field two maxima appeared at the angles of 12 and 24 minute. In the case of the magnetic field directed in parallel to the scattering vector, the two maxima disappeared as expected. It is evidence that nuclear scattering is less than magnetic one and the observed maxima correspond to (10) and (20) reflections from a two dimensional ferro-magnetic microcell. The cell parameter of the magnetic microcell was found 40.6 nm. The coherent scattering region size was 120-160 nm. The ferro-magnetic rod diameter estimated from the peak widths was 16 nm. The diffraction pattern for the demagnetized sample strongly differs from the initial magnetized sample, where a diffuse reflection was observed near Bragg reflection and related with residual magnetization. So, the magnetic inclusions created in the Fe-Co-Ni-Al-Cu system at the thermomagnetic annealing by means of disintegration of the solid solution are strong ferro-magnetic and one-domain. These particles form the two-dimensional magnetic microcell and interact each to other within 3-4 periods of the cell. (authors)

  1. Effect of Cu addition on coercivity and interfacial state of Nd-Fe-B/Nd-rich thin films

    International Nuclear Information System (INIS)

    Matsuura, M; Sugimoto, S; Fukada, T; Tezuka, N; Goto, R

    2010-01-01

    This study provides the effect of Cu addition on coercivity (H cJ ) and interfacial microstructure in Nd-Fe-B/Nd-rich thin films. All films were deposited by using ultra high vacuum (UHV) magnetron sputtering, and the Nd-Fe-B layer was oxidized under several atmospheres with different oxygen content. Then, the films were annealed at 250-550 0 C under UHV. The films oxidized in low vacuum (10 -2 -10 -5 Pa) (under low oxygen state) exhibited the recovery of H cJ by the annealing at 450 0 C. On the contrary, the H cJ of the films oxidized in Ar (under high oxygen state) decreased with increasing annealing temperature. However, the H cJ increased drastically at the temperatures above 550 0 C. In addition, the Cu added films, which were annealed at temperatures above 350 0 C, showed higher coercivities than the films without Cu addition. The XRD analysis suggested the existence of C-Nd 2 O 3 phase in the Cu added films annealed at 550 0 C. It can be considered that the Cu addition decreases the eutectic temperature of Nd-rich phase and influences the interfacial state between Nd 2 Fe 14 B and Nd-rich phase.

  2. Distorted chain sites for Co- and Fe-substituted YBa2Cu3O/sub 7-δ/

    International Nuclear Information System (INIS)

    Bridges, F.; Boyce, J.B.; Claeson, T.; Geballe, T.H.; Tarascon, J.M.; Xerox Palo Alto Research Center, Palo Alto, California 94304; Physics Department, Chalmers University of Technology, S-41296 Gothenburg, Sweden; Department of Applied Physics, Stanford University, Stanford, California 94305; Bell Communications Research Laboratory, Red Bank, New Jersey 07701)

    1989-01-01

    We present x-ray-absorption fine-structure (XAFS) measurements for a series of Co- and Fe-substituted samples of YBa 2 Cu 3 O/sub 7-δ/(Y-Ba-Cu-O). Our analysis of the first- and second-neighbor environments indicates that the Co atoms primarily replace the Cu in the chain sites, the Cu(1) atoms, in Y-Ba-Cu-O, but many of these Co(1) sites and their neighboring oxygen sites are highly distorted. The first-neighbor Co-O peak consists of approximately 3.5 oxygen at 1.8 A and approximately 1.3 oxygen at 2.4 A, while the second-neighbor multipeak in the XAFS data is unexpectedly low in amplitude. Structure in this peak is inconsistent with a simple Gaussian broadening and indicates that several Co(1)-Ba distances exist. We propose an aggregation of the Co atoms into distorted, zigzag chains along the directions, with some of the Co displaced off center by approximately 0.4 A along a perpendicular direction. This model is consistent with the second-neighbor XAFS data, provides an explanation for the tetragonal structure via twinning on a microscopic scale, and accommodates excess oxygen within the Co chains. The Fe data suggest that similar chains also exist in the Fe-substituted samples. There are, however, some differences between the local environments of the Fe and Co. The primary difference is that a small but significant number of Fe atoms occupy the Cu(2) plane sites while no appreciable number of Co atoms are found on the Cu(2) sites in the more dilute samples. Finally, near-edge measurements on the Co and Fe K-absorption edges indicate that the valence is primarily +3, but a mixture of valences exists. For Co the edge position corresponds to a mixture of +2 and +3 valences, while Fe exists in a mixture of +2, +3, and +4 states

  3. The Influence of CuFe2O4 Nanoparticles on Superconductivity of MgB2

    Science.gov (United States)

    Novosel, Nikolina; Pajić, Damir; Skoko, Željko; Mustapić, Mislav; Babić, Emil; Zadro, Krešo; Horvat, Joseph

    The influence of CuFe2O4 nanoparticle doping on superconducting properties of Fe-sheated MgB2 wires has been studied. The wires containing 0, 3 and 7.5 wt.% of monodisperse superparamagnetic nanoparticles (˜7 nm) were sintered at 650°C or 750°C for 1 hour in the pure argon atmosphere. X-ray diffraction patterns of doped samples showed very small maxima corresponding to iron boride and an increase in the fraction of MgO phase indicating some interaction of nanoparticles with Mg and B. Both magnetic and transport measurements (performed in the temperature range 2-42 K and magnetic field up to 16 T) showed strong deterioration of the superconducting properties upon doping with CuFe2O4. The transition temperatures, Tc, of doped samples decreased for about 1.4 K per wt.% of CuFe2O4. Also, the irreversibility fields Birr(T) decreased progressively with increasing doping. Accordingly, also the suppression of Jc with magnetic field became stronger. The observed strong deterioration of superconducting properties of MgB2 wires is at variance with reported enhancement of critical currents at higher temperatures (determined from magnetization) in bulk MgB2 samples doped with Fe3O4 nanoparticles. The probable reason for this discrepancy is briefly discussed

  4. Magnetostatic coupling of 900 domain walls in Fe19Ni81/Cu/Co trilayers

    International Nuclear Information System (INIS)

    Kurde, J; Miguel, J; Kuch, W; Bayer, D; Aeschlimann, M; Sanchez-Barriga, J; Kronast, F; Duerr, H A

    2011-01-01

    The magnetic interlayer coupling of Fe 19 Ni 81 /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 (DWs) of each ferromagnetic layer. We attribute the non-parallel coupling of the two magnetic layers to local magnetic stray fields arising at DWs in the magnetically harder Co layer. In the magnetically softer FeNi layer, non-ordinary DWs, such as 270 0 and 90 0 DWs 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 magnetic anisotropy, both types of overshooting DWs are energetically equivalent. However, if a uniaxial in-plane anisotropy is present, the relative orientation of the DWs with respect to the anisotropy axis determines which of these DWs is energetically favorable.

  5. Scattering of atomic and molecular ions from single crystal surfaces of Cu, Ag and Fe

    International Nuclear Information System (INIS)

    Zoest, J.M. van.

    1986-01-01

    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 H 2 + 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. Investigation of magnetoimpedance effect on electrodeposited NiFe/Cu wire using inductance spectroscopy

    International Nuclear Information System (INIS)

    Mishra, Amaresh Chandra; Sahoo, Trilochan; Srinivas, V.; Thakur, Awalendra K.

    2011-01-01

    In this report, inductance spectroscopy (IS) has been used as a tool to investigate the thickness dependence of magnetoimpedance (MI) on electrodeposited NiFe thin films. An MI value as high as 140% has been observed under an applied magnetic field of 76 Oe at 300 kHz frequency for a film thickness of 6.8 μm. This result is in sharp contrast to earlier reports in literature showing monotonous increase in MI as a function of thickness. Maximum of MI was found at an optimum film thickness whose position varies with frequency. These reports exhibiting strong frequency dependence of MI prompted us to investigate the underlying physics using IS. The origin of MI lies in the combined effect of domain wall motion and spin rotation, which contributes to permeability. A parallel inductance and resistance (LR) circuit in series with series LR circuit model has been proposed as an equivalent electrical model to describe the property of these coated wires. The circuit elements have been linked with the phenomenon of domain wall motion and spin rotation. The experimental results obtained appear to be consistent with the proposed equivalent circuit model. -- Research Highlights: →GMI study on electrodeposited NiFe/Cu wire has been done to resolve the existing controversies. →Inductance spectroscopy has been used to evaluate the magnetic character. →The sample has been modeled as an equivalent electrical circuit. →A correlation between circuit parameters and GMI has been achieved.

  7. 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.

  8. Possibilities of Fe-RICH phases elimination with using heat treatment in secondary Al-Si-Cu cast alloy

    Directory of Open Access Journals (Sweden)

    L. Hurtalová

    2015-01-01

    Full Text Available The mechanical properties of Al-Si-Cu cast alloy are strongly dependent upon the morphologies, type and distribution of the second phases. The skeleton like – Al15(FeMn 3Si2 and needles - Al5FeSi phases were observed in experimental material AlSi9Cu3. The Fe-rich phases morphology was affected with applying two types of heat treatment, T4 and T6, which caused positive changes of mechanical properties especially ultimate tensile strength, gives that for as cast state was Rm = 211 MPa, than at optimum T4 (515 °C/ 4 hours was Rm = 273 MPa and at optimum T6 (515 °C/ 4 hours with artificial aging 170 °C/ 16 hours was Rm = 311 MPa.

  9. Synthesis and densification of Cu added Fe-based BMG composite powders by gas atomization and electrical explosion of wire

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.C., E-mail: jckimpml@ulsan.ac.k [University of Ulsan, School of Materials Science and Engineering, Ulsan 680-749 (Korea, Republic of); Ryu, H.J.; Kim, J.S. [University of Ulsan, School of Materials Science and Engineering, Ulsan 680-749 (Korea, Republic of); Kim, B.K.; Kim, Y.J. [Department of Powder Materials, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Kim, H.J. [Advanced Materials Division, Korea Institute of Industrial Technology, Incheon 406-130 (Korea, Republic of)

    2009-08-26

    In this study, the Fe-based (Fe-C-Si-B-P-Cr-Mo-Al) BMG powders were produced by the high pressure gas atomization process, and they were combined with the ductile Cu powders produced by the electrical explosion of wire (EEW). The Fe-based amorphous powders and Cu added BMG composite powders were compacted by the spark plasma sintering (SPS) processes into cylindrical shape. In the SPS press, the as-prepared powders were sintered at 793 K and 843 K. The relative density increased to 98% when the pressure increased up to 500 MPa by optimum control of the SPS process parameters. The micro-Vickers hardness was over 1100 Hv.

  10. An assessment of the homogeneity of nano-crystalline Fe-Cu powders as studied by means of APT

    Energy Technology Data Exchange (ETDEWEB)

    Wille, Catharina, E-mail: cwille@ump.gwdg.de [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Al-Kassab, Talaat [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany); Choi, Pyuck-Pa [Korea Institute of Science and Technology, Nano-Materials Research Center, Seoul (Korea, Republic of); Kwon, Young-Soon [Research Center for Machine Parts and Materials Processing, University of Ulsan, Ulsan (Korea, Republic of); Kirchheim, Reiner [Georg-August-University Goettingen, Institute for Materials Physics, Goettingen 37077 (Germany)

    2009-04-15

    In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements.

  11. An assessment of the homogeneity of nano-crystalline Fe-Cu powders as studied by means of APT

    International Nuclear Information System (INIS)

    Wille, Catharina; Al-Kassab, Talaat; Choi, Pyuck-Pa; Kwon, Young-Soon; Kirchheim, Reiner

    2009-01-01

    In this contribution the homogeneity of mechanically alloyed Fe-Cu powders for two different compositions (Fe-10 and Fe-2.5 at%Cu) has been systematically characterised by atom probe tomography. Since Fe-Cu exhibits the Invar effect, it is among the most attractive systems for technical application. Furthermore, this system is immiscible and characterised by a large positive heat of mixing. In combination with the widespread application and accessibility, this predestines Fe-Cu as a binary model alloy to elaborate the enforced nonequilibrium enhanced solubility for immiscible systems. Depending on the parameters composition and milling time, results on the extension of the solubility limit and on the homogeneity of the alloy are presented, discussed and compared to earlier works. Only for the alloy with lower Cu content and for the prolonged milling time of 50 h, chemical homogeneity of the sample as measured by the atom probe was fully reached on the nano-scale. For all other parameter combinations homogeneity could not be achieved, even for long milling times and for those samples that appear to be homogeneous via X-ray analysis. Moreover, impurities were determined, mostly stemming from the fabrication procedure. The arrangement and homogeneity of the most common impurity, oxygen, was evaluated from atom probe data for different samples. Thus, the local concentration, segregation effects and the distribution of impurities could be quantified on the nano-scale, depending on the different nominal compositions and processing parameters. Additionally, structural information could be gained employing transmission electron microscopy and diffraction measurements.

  12. 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.

  13. 57Fe Moessbauer study of amorphous and nanocrystalline Fe73.5Nb3Cu1Si13.5B9 after neutron irradiation

    International Nuclear Information System (INIS)

    Miglierini, M.; Sitek, J.; Szasz, Z.; Vitazek, K.

    1994-01-01

    57 Fe Moessbauer spectroscopy is used to study neutron irradiation induced changes in the short-range order of Fe 73.5 Nb 3 Cu 1 Si 13.5 B 9 alloy. The samples are investigated in both amorphous and nanocrystalline states. Neutron irradiation leads to an increase of the standard deviation of a hyperfine field distribution (HFD), implying rearrangement of the atoms towards disordering. Simultaneously, changes in the average value of the hyperfine field and a net magnetic moment position occur as a consequence of a spin reorientation, atom mixing and microscopic stress centres which are introduced by neutron irradiation. (orig.)

  14. Spectroscopic, structural and computational analysis of [Re(CO)3(dippM)Br](n+) (dippM = 1,1'-bis(diiso-propylphosphino)metallocene, M = Fe, n = 0 or 1; M = Co, n = 1).

    Science.gov (United States)

    Furneaux, Aliza G; Piro, Nicholas A; Hernández Sánchez, Raúl; Gramigna, Kathryn M; Fey, Natalie; Robinson, Michael J; Kassel, W Scott; Nataro, Chip

    2016-03-21

    While the redox active backbone of bis(phosphino)ferrocene ligands is often cited as an important feature of these ligands in catalytic studies, the structural parameters of oxidized bis(phosphino)ferrocene ligands have not been thoroughly studied. The reaction of [Re(CO)3(dippf)Br] (dippf = 1,1'-bis(diiso-propylphosphino)ferrocene) and [NO][BF4] in methylene chloride yields the oxidized compound, [Re(CO)3(dippf)Br][BF4]. The oxidized species, [Re(CO)3(dippf)Br][BF4], and the neutral species, [Re(CO)3(dippf)Br], are compared using X-ray crystallography, cyclic voltammetry, visible spectroscopy, IR spectroscopy and zero-field (57)Fe Mössbauer spectroscopy. In addition, the magnetic moment of the paramagnetic [Re(CO)3(dippf)Br][BF4] was measured in the solid state using SQUID magnetometry and in solution by the Evans method. The electron transfer reaction of [Re(CO)3(dippf)Br][BF4] with acetylferrocene was also examined. For additional comparison, the cationic compound, [Re(CO)3(dippc)Br][PF6] (dippc = 1,1'-bis(diiso-propylphosphino)cobaltocenium), was prepared and characterized by cyclic voltammetry, X-ray crystallography, and NMR, IR and visible spectroscopies. Finally, DFT was employed to examine the oxidized dippf ligand and the oxidized rhenium complex, [Re(CO)3(dippf)Br](+).

  15. Redox chemistry of a binary transition metal oxide (AB2O4): a study of the Cu(2+)/Cu(0) and Fe(3+)/Fe(0) interconversions observed upon lithiation in a CuFe2O4 battery using X-ray absorption spectroscopy.

    Science.gov (United States)

    Cama, Christina A; Pelliccione, Christopher J; Brady, Alexander B; Li, Jing; Stach, Eric A; Wang, Jiajun; Wang, Jun; Takeuchi, Esther S; Takeuchi, Kenneth J; Marschilok, Amy C

    2016-06-22

    Copper ferrite, CuFe2O4, is a promising candidate for application as a high energy electrode material in lithium based batteries. Mechanistic insight on the electrochemical reduction and oxidation processes was gained through the first X-ray absorption spectroscopic study of lithiation and delithiation of CuFe2O4. A phase pure tetragonal CuFe2O4 material was prepared and characterized using laboratory and synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. Ex situ X-ray absorption spectroscopy (XAS) measurements were used to study the battery redox processes at the Fe and Cu K-edges, using X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and transmission X-ray microscopy (TXM) spectroscopies. EXAFS analysis showed upon discharge, an initial conversion of 50% of the copper(ii) to copper metal positioned outside of the spinel structure, followed by a migration of tetrahedral iron(iii) cations to octahedral positions previously occupied by copper(ii). Upon charging to 3.5 V, the copper metal remained in the metallic state, while iron metal oxidation to iron(iii) was achieved. The results provide new mechanistic insight regarding the evolution of the local coordination environments at the iron and copper centers upon discharging and charging.

  16. Magnetic and structural properties of Cu{sub 0.85}Fe{sub 0.15}O system synthesized by co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Colorado, H. D., E-mail: herdacom@gmail.com; Perez Alcazar, G. A. [Universidad del Valle, Departamento de Fisica (Colombia)

    2011-11-15

    Cu{sub 0.94}Fe{sub 0.06}O and Cu{sub 0.85}Fe{sub 0.15}O samples were synthesized by using the co-precipitation chemical method. Starting from aqueous solutions of copper nitrate, CuO (NO{sub 3}){sub 2} 3H{sub 2}O, iron nitrate, Fe (NO{sub 3}){sub 3} 9H{sub 2}O and sodium hydroxide as precipitating agent, NaOH. The precipitate of three samples for Cu{sub 0.94}Fe{sub 0.06}O and five for Cu{sub 0.85}Fe{sub 0.15}O of fine powder were calcined for 5 h at different temperatures. The obtained X rays diffraction patterns refined by the Rietveld method show the CuO characteristic pattern, showing that the Fe atoms enter to replace Cu atoms. Furthermore, it was obtained that the crystallite size decreases with calcination temperatures for Cu{sub 0.94}Fe{sub 0.06}O. The transmission Moessbauer spectroscopy showed that the samples present a disordered paramagnetic behavior due to the big value of the half-width of line of the quadrupolar splitting. Vibrating sample magnetometry confirms the paramagnetic character. The XRD results indicate that the material is nanostructured, due that the crystallite sizes are of the order of 10 nm for Cu{sub 0.94}Fe{sub 0.06}O and 40 nm for Cu{sub 0.85}Fe{sub 0.15}O.

  17. A facile FeBr3 based photoATRP for surface modification of mesoporous silica nanoparticles for controlled delivery cisplatin

    Science.gov (United States)

    Huang, Long; Liu, Meiying; Mao, Liucheng; Huang, Qiang; Huang, Hongye; Zeng, Guangjian; Tian, Jianwen; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2018-03-01

    Mesoporous silica nanoparticles (MSNs) should be one of the most important materials for biomedical application owing to their high specific surface area, regular porous structure, adjustable pore size and chemical inert. However, the biomedical applications of unmodified MSNs are largely impeded for their poor hydrophilicity and lack of functional groups. In this work, a novel photo-initiated atom transfer radical polymerization (ATRP) strategy has been reported for modified mesoporous silica nanoparticles (MSNs) with hydrophilicility copolymers using FeBr3 as the novel photocatalyst and itaconic acid (IA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) as monomers. Because of the hydrophilicity and anticancer agent cis-dichlorodiamineplatinum(II) (CDDP) loading capacity of poly(MPC-co-IA), the controlled drug delivery applications MSNs-NH2-poly(MPC-co-IA) composites toward CDDP were further investigated. A series of characterization results demonstrated that MSNs-NH2-poly(MPC-co-IA) composites can be successfully fabricated through the novel photo-initiated ATRP. MSNs-NH2-poly(MPC-co-IA) composites showed obvious enhancement of water dispersibility, desirable biocompatibility, high drug loading capability, making them great potential for controlled drug delivery of CDDP. Moreover, as compared with the traditional ATRP, that using the transition metal ions and organic ligands as the catalysis systems in elevated temperature, our method provides a more facile, benign and cost-effective route for fabrication of multifunctional MSNs with great potential for biomedical applications. Finally, this FeBr3 based photoATRP strategy should be further extended for the fabrication of many other polymeric composites owing to its good monomer adoptability.

  18. Effect of Magnetic Field on Surface Morphology and Magnetic Properties of FeCu/Cu Nano layers Prepared by Electrodeposition Technique: Investigation of Magneto-hydrodynamic Effect

    Directory of Open Access Journals (Sweden)

    M. Merikhi

    2015-10-01

    Full Text Available In this paper, the effect of magnetic field on the morphology, structure and magnetic properties of electrodeposited FeCu/Cu thin films was investigated. The films were deposited on Au2PdAg/glass substrates using electrodeposition technique in potentiostatic control. The magnetic fields of 5000 and 7000 Oe were applied on deposition bath during deposition. Two series of thin films were prepared in the same deposition conditions, one in the presence and the other in absence of magnetic field and the products were compared. The results indicate that applying the magnetic field has a significant effect on the growth process, i.e. morphology, crystal structure and magnetic properties of the films. The morphology and structure of the FeCu/Cu Nano layers were studied using X-ray diffraction (XRD and scanning electron microscopy (SEM. The weight percentages of the elements in the deposited multilayers were determined by energy dispersive X-ray spectroscopy (EDS. Magnetic properties of thin films were studied using the vibrating sample magnetometer (VSM.

  19. Anisotropic magnetic interactions and spin dynamics in the spin-chain compound Cu (py) 2Br2 : An experimental and theoretical study

    Science.gov (United States)

    Zeisner, J.; Brockmann, M.; Zimmermann, S.; Weiße, A.; Thede, M.; Ressouche, E.; Povarov, K. Yu.; Zheludev, A.; Klümper, A.; Büchner, B.; Kataev, V.; Göhmann, F.

    2017-07-01

    We compare theoretical results for electron spin resonance (ESR) properties of the Heisenberg-Ising Hamiltonian with ESR experiments on the quasi-one-dimensional magnet Cu (py) 2Br2 (CPB). Our measurements were performed over a wide frequency and temperature range giving insight into the spin dynamics, spin structure, and magnetic anisotropy of this compound. By analyzing the angular dependence of ESR parameters (resonance shift and linewidth) at room temperature, we show that the two weakly coupled inequivalent spin-chain types inside the compound are well described by Heisenberg-Ising chains with their magnetic anisotropy axes perpendicular to the chain direction and almost perpendicular to each other. We further determine the full g tensor from these data. In addition, the angular dependence of the linewidth at high temperatures gives us access to the exponent of the algebraic decay of a dynamical correlation function of the isotropic Heisenberg chain. From the temperature dependence of static susceptibilities, we extract the strength of the exchange coupling (J /kB=52.0 K ) and the anisotropy parameter (δ ≈-0.02 ) of the model Hamiltonian. An independent compatible value of δ is obtained by comparing the exact prediction for the resonance shift at low temperatures with high-frequency ESR data recorded at 4 K . The spin structure in the ordered state implied by the two (almost) perpendicular anisotropy axes is in accordance with the propagation vector determined from neutron scattering experiments. In addition to undoped samples, we study the impact of partial substitution of Br by Cl ions on spin dynamics. From the dependence of the ESR linewidth on the doping level, we infer an effective decoupling of the anisotropic component J δ from the isotropic exchange J in these systems.

  20. Magnetoimpedance effect of the Ni80Fe20/Cu composite wires: The influence of DC current imposed on the Cu base

    Directory of Open Access Journals (Sweden)

    Delu Chen

    2014-06-01

    Full Text Available In this paper, the copper composite wires of 75 μm in diameter with a sputtered layer of Ni80Fe20 permalloy were prepared, with a DC current applied to the basal Cu terminals during the fabrication process. The influence of the DC current on the magnetic configuration and Magneto-Impedance (MI effect was studied. The results indicate that both the current amplitude and actuation duration have significant effect on the magnetic properties of the Ni80Fe20 layer. With appropriate current applied, the induced magnetic field leads to a circumferential magnetic domain structure and reduces significantly the equivalent anisotropy field of Ni80Fe20 layer. Then, the GMI ratio of the composite wires was significantly increased. A maximum GMI of 194.8% can be reached when the current was fixed at 100 mA and the Ni80Fe20 thickness is 780 nm. If the Ni80Fe20 thickness is above 780 nm, the coercivity of the coating layer increases while the GMI ratio of the composite wire reduces, since the magnetic anisotropy of the Ni80Fe20 layer varies from circumferential to longitudinal. The results were explained combining the thermal and magnetic effects of current.

  1. 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.

  2. 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.

  3. Production and mechanical properties of Ti-5Al-2.5Fe-xCu alloys for biomedical applications.

    Science.gov (United States)

    Yamanoglu, Ridvan; Efendi, Erdinc; Kolayli, Fetiye; Uzuner, Huseyin; Daoud, Ismail

    2018-01-30

    In this study, the mechanical, antibacterial properties and cell toxicity response of Ti-5Al2.5Fe alloy with different copper contents were investigated. The alloys were prepared by high-energy ball milling using elemental Ti, Al, Fe, and Cu powders and consolidated by a uniaxial vacuum hot press. Staphylococcus aureus strain ATCC 29213 and Escherichia coli strain ATCC 25922 were used to determine the antibacterial properties of the sintered alloys. The in vitro cytotoxicity of the samples was evaluated with HeLa (ATTC, CCL-2) cells using thiazolyl blue tetrazolium bromide. The mechanical behavior of the samples was determined as a function of hardness and bending tests and analyzed by scanning electron microscopy, energy dispersive x-ray spectroscopy, optical microscopy and x-ray diffraction (XRD). The results showed that the Cu content significantly improved the antibacterial properties. Cu addition prevented the formation of E. coli and S. aureus colonies on the surface of the samples. All samples exhibited very good cell biocompatibility. The alloys with different copper contents showed different mechanical properties, and the results were correlated by microstructural and XRD analyses in detail. Our results showed that Cu has a great effect on the Ti5Al2.5Fe alloy and the alloy is suitable for biomedical applications with enhanced antibacterial activity.

  4. A comprehensive study of magnetic exchanges in the layered oxychalcogenides Sr 3 Fe 2 O 5 Cu 2 Q 2 ( Q = S, Se)

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Minfeng; Mentré, Olivier; Gordon, Elijah E.; Whangbo, Myung-Hwan; Wattiaux, Alain; Duttine, Mathieu; Tiercelin, Nicolas; Kabbour, Houria

    2017-12-01

    The layered oxysulfide Sr3Fe2O5Cu2S2 was prepared, and its crystal structure and magnetic properties were characterized by synchrotron X-ray diffraction (XRD), powder neutron diffraction (PND), Mössbauer spectroscopy measurements and by density functional theory (DFT) calculations. In addition, the spin exchange interactions leading to the ordered magnetic structure of Sr3Fe2O5Cu2S2 were compared with those of its selenium analogue Sr3Fe2O5Cu2Se2. The oxysulfide Sr3Fe2O5Cu2S2 adopts a G-type antiferromagnetic (AFM) structure at a temperature in the range 485–512 K, which is comparable with the three-dimensional (3D) AFM ordering temperature, TN ≈ 490 K, found for Sr3Fe2O5Cu2Se2. Consistent with this observation, the spin exchange interactions of the magnetic (Sr3Fe2O5)2+ layers are slightly greater (but comparable) for oxysulfide than for the oxyselenide. Attempts to reduce or oxidize Sr3Fe2O5Cu2S2 using topochemical routes yield metallic Fe.

  5. Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

    Science.gov (United States)

    Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

    2018-02-01

    In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

  6. 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 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.

  7. Radiation enhanced copper clustering processes in Fe-Cu alloys during electron and ion irradiations as measured by electrical resistivity

    International Nuclear Information System (INIS)

    Ishino, S.; Chimi, Y.; Bagiyono; Tobita, T.; Ishikawa, N.; Suzuki, M.; Iwase, A.

    2003-01-01

    To study the mechanism of radiation-enhanced clustering of copper atoms in Fe-Cu alloys, in situ electrical resistivity measurements are performed during irradiation with 100 MeV carbon ions and with 2 MeV electrons at 300 K. Two kinds of highly pure Fe-Cu alloys with Cu content of 0.02 and 0.6 wt% are used. The results are summarized as follows: - Although there is a steep initial resistivity increase below about 10 μdpa, the resistivity steadily decreases after this initial transient in Fe-0.6wt%Cu alloy, while in Fe-0.02wt%Cu alloy, the resistivity either decreases slowly or stays almost constant. The rate of change in resistivity depends on copper concentration. - The rate of change in resistivity per dpa is larger for electron irradiation than for ion irradiation. - Change in dose rate from 10 -8 to 10 -9 dpa/s slightly enhances the rate of resistivity change per dpa. The decrease in resistivity with dose is considered to be due to clustering or precipitation of copper atoms. The initial abrupt increase in resistivity is too large to be accounted for by initial introduction of point defects before copper clustering. Tentatively the phenomenon is explained as due to the formation of embryos of copper precipitates with a large strain field around them. Quantitative evaluation of the results using resistivity contribution of a unit concentration of Frenkel pairs and that of copper atoms gives an important conclusion that more than one copper atom are removed from solid solution by one Frenkel pair. The clustering efficiency is surprisingly high in the present case compared with the ordinary radiation-induced or radiation-enhanced precipitation processes

  8. Magnetic heat capacities of {kappa} -(BETS){sub 2}FeBr{sub 4} measured by a micro-chip calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, Shuhei; Yamamoto, Takashi; Nakazawa, Yasuhiro [Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Yamashita, Satoshi [RIKEN, Hirosawa, Wako, Saitama 351-0198 (Japan); Kobayashi, Akiko; Kobayashi, Hayao [Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550 (Japan)

    2012-05-15

    Low temperature thermodynamic properties of {kappa} -(BETS){sub 2}FeBr{sub 4} are studied by using a tiny single crystal sample with 1 {mu}g adhered on a micro-chip calorimeter TCG3880. A large thermal anomaly associated with the antiferromagnetic transition of localized d electrons of Fe{sup 3+} was observed around 2.2 K. With the increase of magnetic fields applied parallel to the ac plane, the transition temperature shifts to lower temperature side accompanied by an anisotropic character. We found that the reduction of the transition temperature is largest, when magnetic field was applied parallel to a-axis. This observation is consistent with the previous result obtained by transport measurements which claimed that the spin easy axis is a-axis. The results demonstrate that the microchip calorimeter is effective for conducting thermodynamic measurements of molecular compounds. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Fe(II)/Cu(II) interaction on goethite stimulated by an iron-reducing bacteria Aeromonas Hydrophila HS01 under anaerobic conditions.

    Science.gov (United States)

    Tao, Liang; Zhu, Zhen-Ke; Li, Fang-Bai; Wang, Shan-Li

    2017-11-01

    Copper is a trace element essential for living creatures, but copper content in soil should be controlled, as it is toxic. The physical-chemical-biological features of Cu in soil have a significant correlation with the Fe(II)/Cu(II) interaction in soil. Of significant interest to the current study is the effect of Fe(II)/Cu(II) interaction conducted on goethite under anaerobic conditions stimulated by HS01 (a dissimilatory iron reduction (DIR) microbial). The following four treatments were designed: HS01 with α-FeOOH and Cu(II) (T1), HS01 with α-FeOOH (T2), HS01 with Cu(II) (T3), and α-FeOOH with Cu(II) (T4). HS01 presents a negligible impact on copper species transformation (T3), whereas the presence of α-FeOOH significantly enhanced copper aging contributing to the DIR effect (T1). Moreover, the violent reaction between adsorbed Fe(II) and Cu(II) leads to the decreased concentration of the active Fe(II) species (T1), further inhibiting reactions between Fe(II) and iron (hydr)oxides and decelerating the phase transformation of iron (hydr)oxides (T1). From this study, the effects of the Fe(II)/Cu(II) interaction on goethite under anaerobic conditions by HS01 are presented in three aspects: (1) the accelerating effect of copper aging, (2) the reductive transformation of copper, and (3) the inhibition effect of the phase transformation of iron (hydr)oxides. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 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 743...... to 823 K for one hour was observed, i.e. the grain size of the FeSi phase slightly decreases when the annealing temperature increases from 743 K ot 823 K. The mechanism of the anomalous grain growth may be due to the different nucleation and volume diffusion rates in the samples anneales at low and high...

  11. Separations on a cellulose exchanger with salicylic acid as functional group. [Fe/sup 3//sup+//Cu/sup 2//sup+/, Cu/sup 2//sup+//Ni/sup 2//sup+//, and Cu/sup 2//sup+//Cu complex separations

    Energy Technology Data Exchange (ETDEWEB)

    Burba, P; Lieser, K H [Technische Hochschule Darmstadt (F.R. Germany). Fachbereich Anorganische Chemie und Kernchemie

    1976-07-01

    The use of a cellulose compound containing salicylic acid as functional group (capacity 0.6 mequ./g) for different problems is described. The seperations Fe/sup 3 +//Cu/sup 2 +/ and Cu/sup 2 +//Ni/sup 2 +/ in aqueous solutions are achieved smoothly at pH 2 and 2.5 resp. In organic solvents (pyridine) copper ions are separated from copper complexes as shown by the examples Cu/sup 2 +//(Cu(mnt)/sub 2/)/sup 2 -/ (mnt = maleonitril-1,2-dithiolate) and Cu/sup 2 +//dibenzo(b.i.)(5.9.14.18)tetraazacyclotetradecene-copper (Cu(chel)). The complex (Cu(mnt)/sub 2/)/sup 2 -/ can be labelled with Cu-64 on a separation column, whereas (Cu-(chel)) is substition inert.

  12. Flux creep and penetration in Fe-doped YBa2Cu3O7

    International Nuclear Information System (INIS)

    Mohamed, M.A.; Jung, J.; Franck, J.P.

    1990-01-01

    Measurements of the magnetic-field distribution, flux penetration, and decay of trapped flux were performed for a disc-shaped sample of YBa 2 Cu 2.95 Fe 0.05 O 7-δ at 77 K. Time-dependent magnetic-flux penetration, i.e., a decay of diamagnetic shielding and the Meissner field, was observed for zero-field-cooled (ZFC) and field-cooled (FC) samples. The decays were found to be logarithmic in time. The logarithmic decay rate of diamagnetic shielding depends on an applied magnetic field and reaches its maximum at an applied field of about 30 G. The dependence of a trapped field versus an applied field shows a maximum at an applied field of 100 G for the FC case and 200 G for the ZFC case. The maximum amount of the trapped field is about two times less than that for a pure, undoped YBa 2 Cu 3 O 7-δ sample of similar dimensions. The logarithmic decay rate of the trapped field versus the initial trapped field is described by a linear function with the change of its slope at the trapped field corresponding to an applied field of about 30 G for both the FC and ZFC cases. These results are related to the sample microstructure, i.e., grain size and porosity. Trapped field decays can be explained in terms of the interaction between intergranular vortices and persistent current circulating around normal regions or voids, in the framework of the conventional flux-creep model recently proposed by Hagen, Griessen, and Salomons [Physica 157C, 199 (1989)

  13. Theoretical analysis of experimental tracer and interdiffusion data in Cu-Ni-Fe alloys

    International Nuclear Information System (INIS)

    Belova, I.V.; Murch, G.E.; Filipek, R.; Danielewski, M.

    2005-01-01

    In this paper, we present strategies to extract fundamental atomistic information from measured diffusion coefficients in a ternary alloy system. The strategies are exemplified with Cu-Ni-Fe alloys at 1271 K where recent extensive interdiffusion coefficients and tracer diffusion coefficients for all three components have become available. We develop new defining phenomenological expressions for the vacancy-wind factors in terms of the diffusion coefficients. We show that the measured tracer diffusion coefficients can be processed using the Manning and Moleko, Allnatt and Allnatt random alloy diffusion kinetics formalisms (with and without the assumption of the Gibbs-Duhem relation between the thermodynamic activities) to give jump frequencies, tracer correlation factors, vacancy-wind factors and phenomenological coefficients. It is shown for example that Cu is generally the most correlated component in its diffusion behavior and that the off-diagonal phenomenological coefficients can be as high as 64% of the smallest of the diagonal phenomenological coefficients. It is also shown that the Darken formalism (which ignores off-diagonal phenomenological coefficients) is in fact a reasonable approximation for expressing the diagonal phenomenological coefficients in terms of the tracer diffusion coefficients. It is then shown how the measured interdiffusivities can be processed with these formalisms to give tracer diffusivities, vacancy-wind factors and phenomenological coefficients. Finally, we show how a straightforward strategy starting with the Darken analysis that is then followed by the Manning or Moleko, Allnatt and Allnatt analysis can be used to gain access to the vacancy-wind factors and the off-diagonal phenomenological coefficients

  14. Thermal expansion of organic superconductor κ-(D4-BEDT-TTF)2Cu{N(CN)2}Br. Isotopic effect

    Science.gov (United States)

    Dolbin, A. V.; Khlistuck, M. V.; Eselson, V. B.; Gavrilko, V. G.; Vinnikov, N. A.; Basnukaeva, R. M.; Konstantinov, V. A.; Nakazawa, Y.

    2017-12-01

    Linear thermal expansion coefficient (LTEC) of single crystal κ-(D4-BEDT-TTF)2Cu[N(CN)2]Br was studied across the crystal layers in the temperature range 2-290 K using the method of precise capacitive dilatometry. Below Tc = 11.6 K the LTEC of the sample had a small negative value, which is apparently due to the transition from the paramagnetic metal in the superconducting state. There was a bend of temperature dependence of the LTEC, which shows broad peak around 40 K and can be attributed to the elastic lattice anomaly around the end-point of Mott boundary. A sharp jump in the LTEC values and hysteresis was observed in the area of Tg ˜ 75-77 K, what is likely explained by the transition in a glass-like state. The isotope effect in the thermal expansion is discusses, which manifested itself in a shift of the phase transitions in comparison with fully deuterated BEDT-TTF sample.

  15. Electron spin resonance insight into broadband absorption of the Cu3Bi(SeO3)2O2Br metamagnet

    Science.gov (United States)

    Zorko, A.; Gomilšek, M.; Pregelj, M.; Ozerov, M.; Zvyagin, S. A.; Ozarowski, A.; Tsurkan, V.; Loidl, A.; Zaharko, O.

    2016-05-01

    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(SeO3)2O2Br 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.

  16. Stabilities of thiomolybdate complexes of iron; implications for retention of essential trace elements (Fe, Cu, Mo) in sulfidic waters.

    Science.gov (United States)

    Helz, George R; Erickson, Britt E; Vorlicek, Trent P

    2014-06-01

    In aquatic ecosystems, availabilities of Fe, Mo and Cu potentially limit rates of critical biological processes, including nitrogen fixation, nitrate assimilation and N2O decomposition. During long periods in Earth's history when large parts of the ocean were sulfidic, what prevented these elements' quantitative loss from marine habitats as insoluble sulfide phases? They must have been retained by formation of soluble complexes. Identities of the key ligands are poorly known but probably include thioanions. Here, the first determinations of stability constants for Fe(2+)-[MoS4](2-) complexes in aqueous solution are reported based on measurements of pyrrhotite (hexagonal FeS) solubility under mildly alkaline conditions. Two linear complexes, [FeO(OH)MoS4](3-) and [(Fe2S2)(MoS4)2](4-), best explain the observed solubility variations. Complexes that would be consistent with cuboid cluster structures were less successful, implying that such clusters probably are minor or absent in aqueous solution under the conditions studied. The new data, together with prior data on stabilities of Cu(+)-[MoS4](2-) complexes, are used to explore computationally how competition of Fe(2+) and Cu(+) for [MoS4](2-), as well as competition of [MoS4](2-) and HS(-) for both metals would be resolved in solutions representative of sulfidic natural waters. Thiomolybdate complexes will be most important at sulfide concentrations near the [MoO4](2-)-[MoS4](2-) equivalence point. At lower sulfide concentrations, thiomolybdates are insufficiently stable to be competitive ligands in natural waters and at higher sulfide concentrations HS(-) ligands out-compete thiomolybdates.

  17. Electrical transport and magnetic studies of Nd1-xCaxSr2Cu2FeOδ compounds

    International Nuclear Information System (INIS)

    Walia, R.; Banerjee, R.; Grandjean, D.; Lanchester, P.C.; De Groot, P.A.J.; Weller, M.T.

    1994-01-01

    We have measured the temperature dependence of the DC electrical resistivity and susceptibility in the interval 4.2-300 K for Nd 1-x Ca x Sr 2 Cu 2 FeO δ (x=0.0, 0.1, 0.2 and 0.3). Analysis of the results showed the density of states to be a strong function of x, indicating the existence of short range fluctuations near the Fermi level E F . The magnetic susceptibility, however, shows the oxidation state of Fe remains at +3 for x≥0. ((orig.))

  18. Coating magnetic CuFe2O4 nanoparticles with OMS-2 for enhanced degradation of organic pollutants via peroxymonosulfate activation

    Science.gov (United States)

    Ye, Peng; Wu, Deming; Wang, Manye; Wei, Yi; Xu, Aihua; Li, Xiaoxia

    2018-01-01

    A heterogeneous magnetic CuFe2O4@OMS-2 catalyst was fabricated through a facile solvent-free process using Mn(CH3COO)2 and KMnO4 in the presence of CuFe2O4. It was found that the BET surface area of OMS-2 as well as the ratio of low-valent manganese species significantly increased in the hybrid catalyst, due to interactions between CuFe2O4 and the precursor of amorphous manganese oxide. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the CuFe2O4@OMS-2 catalyst within 30 min in the presence of peroxymonosulfate (PMS), while CuFe2O4 and OMS-2 showed no significant activity for the reaction. The hybrid catalyst also exhibited excellent long-term stability and could be easily recovered with the assistance of an external magnetic field. A possible degradation mechanism for the synergistic effects of different valent metal species and reactive radicals was proposed, which involved the electron transfer from Mn(III) or Mn(II) species to PMS with the generation of sulfate and hydroxyl radicals, and from AO7 and Cu(I) in CuFe2O4 to Mn(IV) and Mn(III) to reduce these Mn species.

  19. 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.

  20. Synthesis and characterization of the 1.1 adducts of copper(1) halides with bidentatate N,N-bis(benzophenone)-1,2-diiminoethane Schiff bases: Crystal structures of [Cu(bz2en)2][CuX2](X=Br,l) complexes

    NARCIS (Netherlands)

    Kia, Reza; Mirkhani, Valiollah; Harkema, Sybolt; van Hummel, G.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

  1. Coercive force changes in Sm(CoFeCuZr)z during step-like heat treatments

    International Nuclear Information System (INIS)

    Puzanova, T.Z.; Shchegoleva, N.N.; Sakhnova, L.V.; Majkov, V.G.; Shur, Ya.S.; Nikolaeva, N.V.

    1987-01-01

    Sm(Co 0.67 Fe 0.22 Cu 0.08 Zr 0.03 ) 8.35 alloy, contaning two homogeneous solid solutions SmM 6.85 and SmM 7.75 (M=Co, Fe, Cu, Zr) after high-temperature treatment, is investigated. It is shown, that after isothermal tempering at 800 deg C, SmM 6.85 and SmM 7.75 are close by microstructure and their coercive forces change in a different way during step-like cooling within 700-400 deg C interval. Possibility of producing material, single-phase in magnetic relation, is discussed

  2. Regularity in the formation of compounds in ternary R-Me-Sn systems, R - REM, Me - Fe, Co, Ni, Cu

    International Nuclear Information System (INIS)

    Skolozdra, R.V.; Komarovskaya, L.P.; Koretskaya, O.Eh.

    1992-01-01

    For the ternary alloy systems of (La, Y, Gd, Lu)-Fe-Sn, (Ce, Y, Gd)-Co-Sn, (Ce, Y, Gd, Lu)-Ni-Sn and (Pr, Gd, Lu)-Cu-Sn isothermal sections of phase diagrams were plotted within the range of 670 to 870 K. It was revealed that substitution of transition metal in the kFe-Co-Ni-Cu series led to changes both in a number of ternary stannides and their structural types. A tendency was observed in change of stannide numbers depending on quantity ratio of R and Me components. Crystallochemical analysis of compounds obtained showed that they could be treated as interstitial structures or lsuperstructures with respect to them. The results of magnetic properties measurements were used for explanation of structural features of ternary compounds considered

  3. 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.

  4. Effect of crystalline electric field on heat capacity of LnBaCuFeO5 (Ln = Gd, Ho, Yb)

    Science.gov (United States)

    Lal, Surender; Mukherjee, K.; Yadav, C. S.

    2018-02-01

    Structural, magnetic and thermodynamic properties of layered perovskite compounds LnBaCuFeO5 (Ln = Ho, Gd, Yb) have been investigated. Unlike the iso-structural compound YBaCuFeO5, which shows commensurate antiferromagnetic to incommensurate antiferromagnetic ordering below ∼200 K, the studied compounds do not show any magnetic transition in measured temperature range of 2-350 K. The high temperature heat capacity of the compounds is understood by employing contributions from both optical and acoustic phonons. At low temperature, the observed upturn in the heat capacity is attributed to the Schottky anomaly. The magnetic field dependent heat capacity shows the variation in position of the anomaly with temperature, which appears due to the removal of ground state degeneracy of the rare earth ions, by the crystalline electric field.

  5. Tensile behavior change depending on the microstructure of a Fe-Cu alloy produced from rapidly solidified powder

    International Nuclear Information System (INIS)

    Kakisawa, Hideki; Minagawa, Kazumi; Halada, Kohmei

    2003-01-01

    The relationship between consolidating temperature and the tensile behavior of iron alloy produced from Fe-Cu rapidly solidified powder is investigated. Fe-Cu powder fabricated by high-pressure water atomization was consolidated by heavy rolling at 873-1273 K. Microstructural changes were observed and tensile behavior was examined. Tensile behavior varies as the consolidating temperature changes, and these temperature-dependent differences depend on the morphology of the microstructure on the order of micrometers. The sample consolidated at 873 K shows a good strength/elongation balance because the powder microstructure and primary powder boundaries are maintained. The samples consolidated at the higher temperatures have a microstructure of recrystallized grains, and these recrystallized samples show the conventional relationship between tensile behavior and grain size in ordinal bulk materials

  6. 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}.

  7. 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.

  8. Photoluminescence and semiconducting behavior of Fe, Co, Ni and Cu implanted in heavy metal oxide glasses

    Directory of Open Access Journals (Sweden)

    Mohamed A. Marzouk

    2016-07-01

    Full Text Available Transition metal ions (0.5 wt% of Fe2O3, CoO, NiO or CuO doped heavy metal oxide glasses having chemical composition of 60PbO·20Bi2O3·20 MxOy mol% (where MxOy = B2O3 or SiO2 or P2O5 were prepared by conventional melt annealing method. Combined optical and photoluminescence properties have been measured and employed to evaluate the prepared glassy samples. From the absorption edge data, the values of the optical band gap Eopt, Urbach energy (ΔE and refractive index were calculated to estimate semiconducting behavior. Photoluminescence and values of the optical energy gap were found to be dependent on the glass composition. The variations of the photoluminescence intensity, values of optical band gap, Urbach energy and refractive index gave an indication to use the prepared glasses for design of novel functional optical materials with higher optical performance.

  9. X-ray resonant Raman scattering cross sections of Mn, Fe, Cu and Zn

    International Nuclear Information System (INIS)

    Sanchez, Hector Jorge; Valentinuzzi, MarIa Cecilia; Perez, Carlos

    2006-01-01

    X-ray fluorescence spectra present singular characteristics produced by the different scattering processes. When atoms are irradiated with incident energy lower and close to an absorption edge, scattering peaks appear due to an inelastic process known as resonant Raman scattering. It constitutes an important contribution to the background of the fluorescent line. The resonant Raman scattering must be taken into account in the determination of low concentration contaminants, especially when the elements have proximate atomic numbers. The values of the mass attenuation coefficients experimentally obtained when materials are analysed with monochromatic x-ray beams under resonant conditions differ from the theoretical values (between 5% and 10%). This difference is due, in part, to the resonant Raman scattering. Monochromatic synchrotron radiation was used to study the Raman effect on pure samples of Mn, Fe, Cu and Zn. Energy scans were carried out in different ranges of energy near the absorption edge of the target element. As the Raman peak has a non-symmetric shape, theoretical models for the differential cross section, convoluted with the instrument function, were used to determine the RRS cross section as a function of the incident energy

  10. Self-lubricating tribological characterization of lead free Fe-Cu based plain bearing material

    Directory of Open Access Journals (Sweden)

    Shuhaib Mushtaq

    2017-03-01

    Full Text Available The negative impact of lead on environment and thereby its reciprocity on the health of mankind, there is a growing emphasis on resisting the usage of lead in bearings. Owing to this, new bearing materials that provide comparable tribological performance to that of lead containing alloys are being developed. In this study, lead free Fe-Cu based powders with addition of elements such as tin, molybdenum disulfide and Nano boron nitride (BN have been developed by powder metallurgy (PM technique in order to improve the tribological and mechanical properties. The powder mixtures were compressed at a pressure of 500 MPa, and then sintered in dry hydrogen atmosphere at 9000C for 50 minutes. The mechanical and tribological properties obtained due to addition of the said elements is presented in this study. The tribological behavior of the selected alloys is analyzed by reciprocating-sliding tests under dry conditions. The morphology of wear scars and the microstructure of the wear surfaces were investigated. The material with 2.5 wt.% of Sn exhibited the highest value of hardness, the material with 7.5 wt.% of Nano BN comparably shows the low coefficient of friction and wear rate as compared with 5 wt.% of Nano BN.

  11. Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 12 Am −2 . Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 10 12 Am −2 to 1.39 × 10 12 Am −2

  12. 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.

  13. Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco

    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.

  14. Dissolution behavior of Cu, Fe and Zn from gold sulfide concentrate during pre-oxidation using ozone in neutral media

    Science.gov (United States)

    Kurniawan, Mubarok, M. Zaki

    2018-04-01

    The aim of this work was to observe the dissolution behaviour of Cu, Fe and Zn from gold sulfide concentrate during preoxidation with ozone as the oxidant and distillation water as the media. The preoxidation experiments were carried out in five-necked reactor with variations of retention time, percent solid, particle size and oxygen dosage injected to ozone generator. The retention time was varied at 6 hours, 8 hours, 12 hours and 24 hours. The percent solid was varied at 10%, 20% and 30% while the particle size was varied at P80 -75 mesh dan P80 -20 mesh. The dosage of oxygen injection to ozone generator was varried at 1 liter per minute and 2 liter per minute. The ozone gas was produced by using ozone generator type OZ-03 and injected to the slurry by using Mazzei injector. The soluble Cu, Fe and Zn were measured by using Atomic Absorption Spectrophotometry (AAS). The concentrates were characterized by X-Ray Diffraction (XRD), mineragraphy, fire assay and Inductively Coupled Plasma (ICP). Fire assay, ICP and XRD were used to analyse the residues and froth. The solubilition of metals (Cu, Fe and Zn) was obtained through the formation of sulphate ion and H+ which decreased the pH, released a number of heat and then was continued by the formation of elemental sulphur (S°). The interaction of particles and gas yielded the formation of froth. The highest dissolution percentage of Cu, Fe and Zn was achieved through 24 hours oxidation at 20% (w/w), P80 -20 mesh and one liter per minute of oxygen injection dosage by 83.016%, 24.7303% and 91.6808%, respectively.

  15. Preparation and electric and photoelectric properties of thin deposits of Fe, Co, Ni, Cu, Ag, Au and Pd

    International Nuclear Information System (INIS)

    Heras, J.M.; Albano, E.V.; Asensio, M.C.; Viscido, L.

    1984-01-01

    The physics chemical properties of desordered metallic thin films of Fe, Co, Ni, Pd, Ag, Cu and Au are of great interest for its catalitic activity and for its application in radiation absorption of solar cells and micro electronic devices. This work has the purpose of reporting the experimental results obtained by evaporated films of these metals, which present desordered characteristics, small crystal size and high surface-volume rate. (A.C.A.S.) [pt

  16. A comparative study of metabolism and concentration factors of Fe, Cu, Zn, Mn, Co and Mg in Carcinus maenas and Cancer irroratus ovaries during ovogenesis

    International Nuclear Information System (INIS)

    Martin, J.-L.M.

    1975-01-01

    Fe, Cu, Zn, Mn, Co, and Mg were analysed in the ovary of Carcinus maenas and Cancer irroratus during ovogenesis. In both ovaries, the relatives rates, expressed as parts per millions as a ratio of wet and dry weight, are the following: Mg>Zn>Fe>Cu>Mn>Co, while in the hemolymph of Cancer irroratus these relative rates are the following: Mg>Cu>Zn>Fe>Mn>Co. Compared to concentrations of these metals in sea water, Mg expected, all metals in the ovary of Cancer irroratus have a concentration factor upper than 1. Compared to the concentration of metals in the hemolymph is, for Fe, Mn, and Co, the concentration factor upper than 1, and for Cu, Zn and Mg, the concentration factor lower than 1. A study of correlations was done between the concentrations of metals considered in pairs, and between the concentrations of metals and the parameters: water content and gonad index [fr

  17. Fabrication and electrochemical properties of activated CNF/Cu x Mn1- x Fe2O4 composite nanostructures

    Science.gov (United States)

    Nilmoung, Sukanya; Sonsupap, Somchai; Sawangphruk, Montree; Maensiri, Santi

    2018-06-01

    This work reports the fabrication and electrochemical properties of activated carbon nanofibers composited with copper manganese ferrite (ACNF/Cu x Mn1- x Fe2O4: x = 0.0, 0.2, 0.4, 0.6, 0.8) nanostructures. The obtained samples were characterized by means of X-ray diffraction, field emission scanning electron microscopy, Brunauer-Emmett-Teller analyzer, thermal gravimetric analysis, X-ray photoemission spectroscopy, and X-ray absorption spectroscopy. The supercapacitive behavior of the electrodes is tested using cyclic voltammetery, galvanostatic charge-discharge and electrochemical impedance spectroscopy. By varying ` x', the highest specific capacitance of 384 F/g at 2 mV/s using CV and 314 F/g at 2 A/g using GCD are obtained for the x = 0.2 electrode. The second one of 235 F/g at 2 mV/s using CV and 172 F/g at 2 A/g using GCD are observed for x = 0.8 electrode. The corresponding energy densities are 74 and 41 Wh/kg, respectively. It is observed that the cyclic stability of the prepared samples strongly depend on the amount of carbon, while the specific capacitance was enhanced by the sample with nearly proportional amount between carbon and CuMnFe2O4. Such results may arise from the synergetic effect between CuMnFe2O4 and ACNF.

  18. Determination of Mn, Fe, and Cu in chemically-treated wood pulps by the XRF addition method

    Energy Technology Data Exchange (ETDEWEB)

    Raemoe, J.; Klasila, T.; Piepponen, S. [VTT Chemical Technology (Finland); Sillanpaeae, M. [Oulu Univ. (Finland)

    2001-08-01

    A rapid X-ray fluorescence addition method has been developed for quantification of the technically most important metals in wood pulp matrix (Mn, Fe, and Cu). Pretreatment consisted of just two steps: first, acid was added to the sample to achieve homogeneous distribution of the metals; the pulp was then pressed lightly on to Mylar film. Total analysis time was less than 10 min. The concentration range investigated was up to 15 mg kg{sup -1} for Mn and up to 5 mg kg{sup -1} for Fe and Cu. Metal concentrations in Scandinavian pulps are not expected to exceed these amounts. The quantification limit was 2 mg kg{sup -1} for all three metals. The reproducibilities and repeatabilities were concentration-dependent and varied between 3 and 19% and between 1 and 17%, respectively. The squares of the linear correlation coefficients between measured intensity and added metal concentration were 0.994, 0.950, and 0.932 for Mn, Fe, and Cu, respectively. (orig.)

  19. Validation and uncertainty estimation of fast neutron activation analysis method for Cu, Fe, Al, Si elements in sediment samples

    International Nuclear Information System (INIS)

    Sunardi; Samin Prihatin

    2010-01-01

    Validation and uncertainty estimation of Fast Neutron Activation Analysis (FNAA) method for Cu, Fe, Al, Si elements in sediment samples has been conduced. The aim of the research is to confirm whether FNAA method is still matches to ISO/lEC 17025-2005 standard. The research covered the verification, performance, validation of FNM and uncertainty estimation. Standard of SRM 8704 and sediments were weighted for certain weight and irradiated with 14 MeV fast neutron and then counted using gamma spectrometry. The result of validation method for Cu, Fe, Al, Si element showed that the accuracy were in the range of 95.89-98.68 %, while the precision were in the range 1.13-2.29 %. The result of uncertainty estimation for Cu, Fe, Al, and Si were 2.67, 1.46, 1.71 and 1.20 % respectively. From this data, it can be concluded that the FNM method is still reliable and valid for element contents analysis in samples, because the accuracy is up to 95 % and the precision is under 5 %, while the uncertainty are relatively small and suitable for the range 95 % level of confidence where the uncertainty maximum is 5 %. (author)

  20. 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.

  1. Study of defect annealing behaviour in neutron irradiated Cu and Fe using positron annihilation and electrical conductivity

    International Nuclear Information System (INIS)

    Eldrup, M.; Singh, B.N.

    2000-01-01

    To compare the defect accumulation and the annealing behaviour in an fcc and a bcc metal, OFHC-Cu and pure Fe were neutron irradiated at 100 deg. C to a fluence of 1.5 x 10 24 n/m 2 , (E > 1 MeV). Isochronal annealing was carried out and the annealing behaviour followed by positron annihilation spectroscopy (PAS) as well as electrical conductivity measurements. The results for the two specimens in the as-irradiated state are very different. In Cu the defect positron lifetime is characteristic of single vacancies, very small vacancy clusters or stacking fault tetrahedra, while in Fe the defect lifetimes confirm the presence of micro-voids and voids. The electrical conductivity, on the other hand does not discriminate between the two types of damage in the irradiated specimens. During annealing of the irradiated Fe below stage V, the average void size grows by migration and coalescence of the micro-voids and voids. At and above stage V the void density decreases and the voids finally anneal out at ∼500 deg. C. In contrast, the annealing of irradiated Cu below stage V does not yield any evidence for the evolution of micro-voids or voids. The implications of these results are discussed. One conclusion is that neutron irradiation below stage V causes higher void swelling in bcc iron than in fcc copper

  2. 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.

  3. Nitrite to nitric oxide interconversion by heme FeII complex assisted by [CuI(tmpa)]+

    KAUST Repository

    Turias, Francesc; Solà , Miquel; Falivene, Laura; Cavallo, Luigi; Poater, Albert

    2015-01-01

    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

  4. 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

  5. Analysis of isomer shift and quadrupole splitting in moessbauer effect for (La1-xSrx)2Cu0.99Fe0.01O4

    International Nuclear Information System (INIS)

    Arai, Juichiro; Nitta, Takehiko

    1997-01-01

    Moessbauer effect is measured for the high-T c superconductors (La 1-x Sr x ) 2 Cu 0.99 Fe 0.01 O 4 (x = 0-0.17) at room temperature. Both the values of quadrupole splitting (E q ) and isomer shift (I.S.) decrease with increasing x. In order to interpret the large E q value in the sample of x 0, the presence of Fe-4p electrons must be taken into account and the analysis of E q decrease for x = 0 to 0.17 gives the increase of Fe-3d holes, Δn 3d = 0.09. The decrease of I.S. can be analyzed by shield effect due to the increase of Fe-3d holes, which gives the same Δn 3d value. The agreement of both the values indicates that hole increase in Fe-3d orbital is responsible for the decrease of both E q and I.S., and Fe-4p and 4s electrons, even if exist, hardly change with Sr concentration. Furthermore, the valence state of Fe ions in the undoped sample of x = 0 is estimated; Fe3d 4.8 4p 0.18 . This is compared with the reported Cu valence state obtained from NQR and their difference is discussed on the basis of energy level difference of 3d orbital in Fe and Cu ions in CuO 2 plane. (author)

  6. Application of neutron activation analysis to evaluate the health status of equines by means of Cu, Fe, Mn and Zn determinations in their hair

    International Nuclear Information System (INIS)

    Armelin, M.J.A.; Avila, R.L.; Piasentin, R.M.; Saiki, M.

    2001-01-01

    Instrumental neutron activation analysis (INAA) was applied to evaluate the clinical status of equines, belonging to the Military Police of Sao Paulo State, by means of Cu, Fe, Mn and Zn determinations in their hair. Comparison of the results obtained in these analyses with reference values indicated Zn deficiency in the equines, Fe is in the minimum limit and the elements Cu and Mn are within the normal range. (author)

  7. Fabrication of Fe{sub 3}O{sub 4}@CuO core-shell from MOF based materials and its antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Rajabi, S.K. [Department of Chemistry, University of Guilan, University Campus 2, Rasht (Iran, Islamic Republic of); Sohrabnezhad, Sh., E-mail: sohrabnezhad@guilan.ac.ir [Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 1914, Rasht (Iran, Islamic Republic of); Ghafourian, S. [Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam (Iran, Islamic Republic of)

    2016-12-15

    Magnetic Fe{sub 3}O{sub 4}@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe{sub 3}O{sub 4}@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe{sub 3}O{sub 4} core and a CuO shell. The Fe{sub 3}O{sub 4}@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe{sub 3}O{sub 4}-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent. - Graphical abstract: Fe{sub 3}O{sub 4}@CuO core-shell release of copper ions. These Cu{sup 2+} ions were responsible for the exhibited antibacterial activity. - Highlights: • The Fe{sub 3}O{sub 4}@CuO core-shell was prepared by MOF method. • This is the first study of antibacterial activity of core-shell consist of CuO and Fe{sub 3}O{sub 4}. • The core-shell can be reused effectively. • Core-shell was separated from the reaction solution by external magnetic field.

  8. Influence of Cu on modifying the beta phase and enhancing the mechanical properties of recycled Al-Si-Fe cast alloys.

    Science.gov (United States)

    Basak, C B; Babu, N Hari

    2017-07-18

    High iron impurity affects the castability and the tensile properties of the recycled Al-Si alloys due to the presence of the Fe containing intermetallic β-Al 9 Fe 2 Si 2 phase. To date only Mn addition is known to transform the β-Al 9 Fe 2 Si 2 phase in the Al-Si-Fe system. However, for the first time, as reported here, it is shown that β-phase transforms to the ω-Al 7 Cu 2 Fe phase in the presence of Cu, after solutionization at 793 K. The ω-phase decomposes below 673 K resulting into the formation of θ-Al 2 Cu phase. However, the present thermodynamic description of the Al-Si-Fe-Cu system needs finer tuning to accurately predict the stability of the ω-phase in these alloys. In the present study, an attempt was made to enhance the strength of Al-6wt%Si-2wt%Fe model recycled cast alloy with different amount of Cu addition. Microstructural and XRD analysis were carried out in detail to show the influence of Cu and the stability range of the ω-phase. Tensile properties and micro-hardness values are also reported for both as-cast and solutionized alloys with different amount of Cu without and with ageing treatment at 473 K. The increase in strength due to addition of Cu, in Fe-rich Al-Si alloys is promising from the alloy recyclability point of view.

  9. Monitoring of corrosion rates of Fe-Cu alloys under wet/dry condition in weakly alkaline environments

    International Nuclear Information System (INIS)

    Kim, Je Kyoung; Nishikata, Atsushi; Tsuru, Tooru

    2002-01-01

    When the steel, containing scrap elements like copper, is used as reinforcing steel bars for concrete, the steel is exposed to alkaline environments. in this study, AC impedance technique has been applied to the monitoring of corrosion rates of iron and several Fe-Cu (0.4, 10wt%) alloys in a wet-dry cycle condition. The wet-dry cycle was conducted by exposure to alternate conditions of 1 hour-immersion in a simulated pH10 concrete solution (Ca(OH) 2 ) containing 0.01M NaCl and 3 hour-drying at 298K and 50%RH. The corrosion rate of the iron is greatly accelerated by the wet-dry cycles. Because the active FeOOH species, which are produced by the oxidation of Fe(II, III)oxide in air during drying, act as very strong oxidants to the corrosion in the wet condition. As the drying progresses, iron shows a large increase in the corrosion rate and a small shift of the corrosion potential to the positive values. This can be explained by acceleration of oxygen transport through the thin electrolyte layer In contrast to iron, the Fe-Cu alloys show low corrosion rates and the high corrosion potentials in whole cycles

  10. Mineralogy and skarnification processes at the Avan Cu-Fe Skarn, northeast of Kharvana, NW Iran

    Directory of Open Access Journals (Sweden)

    Mir Ali Asghar Mokhtari

    2017-02-01

    Full Text Available Introduction The Avan Cu-Fe skarn is located at the southern margin of Qaradagh batholith, about 60 km north of Tabriz. The Skarn-type metasomatic alteration is the result of Qaradagh batholith intrusion into the Upper Cretaceous impure carbonates. The studied area belongs to the Central Iranian structural zone. In regional scale, the studied area is a part of the Zangezour mineralization zone in the Lesser Caucasus. Several studies (Karimzadeh Somarin and Moayed, 2002; Calagari and Hosseinzadeh, 2005; Mokhtari, 2008; Baghban Asgharinezhad, 2012; Mokhtari, 2012 including master’s theses and research programs have been done on some skarns in the Azarbaijan area considering their petrologic and mineralization aspects. However, before this study, the Avan skarn aureole has not been studied in detail. In this paper, various geological aspects of the Avan skarn including mineralogy, bi-metasomatic alteration, metasomatism and mineralization during the progressive and retrograde stages of the skarnification processes have been studied in detail. Research Method This research consists of field and laboratory studies. Field studies include preparation of the geological map, identifying the relationship between the intrusion and the skarn aureole, identifying the relationship between different parts of the skarn zone and also collecting samples for laboratory studies. Laboratory studies include petrography, mineralography and microprobe studies. Cameca SX100 Microprobe belonging to Geological Survey of the Czech Republic was used in order to determine the chemical composition of the calc-silicate minerals such as pyroxene and garnet in garnet skarn and pyroxene- garnet skarn sub-zones. Discussion and conclusion Qaradagh batholith is composed of discrete acid to mafic phases including gabbro, diorite, quartz diorite, quartz monzonite, quartz monzodiorite, tonalite, granodiorite, monzogranite and granite porphyry which is dominated by granodiorite

  11. Fe site occupancy and superconductivity in Y1-zCazBaz(Cu1-xFex)3O6+y

    International Nuclear Information System (INIS)

    Smith, M.G.; Taylor, R.D.; Oesterreicher, H.

    1990-01-01

    X-ray diffraction and 57 Fe Moessbauer spectroscopy studies show that partial substitution of Ca for Y in Y 1-z Ca z Ba 2 (Cu 1-x Fe x ) 3 O 6+y (0.05 ≤ z ≤ 0.15,0.003 ≤ x ≤ 0.20) result in increased Fe solubility and a larger percentage of Fe occupancy of the Cu(2) plane site (prepared conventionally). Materials with z > 0.00 have a slightly depressed superconducting transition onset temperature T c relative to the z = 0.00 compounds. It is also shown that Fe occupancy of the Cu(2) site in Y 1-z Ca z Ba 2 (Cu 1-x Fe x ) 3 O 6+y can be substantially increased when these materials are treated at high temperatures in inert atmospheres followed by oxygenation at low temperatures. T c decreases more rapidly in these latter materials compared to the conventionally prepared ones. Implications concerning ordered Fe cluster formation and superconducting pair breaking in the Cu(2) site are drawn. 7 refs., 4 tabs

  12. Radical scavenging propensity of Cu2 +, Fe3 + complexes of flavonoids and in-vivo radical scavenging by Fe3 +-primuletin

    Science.gov (United States)

    Jabeen, Erum; Janjua, Naveed Kausar; Ahmed, Safeer; Murtaza, Iram; Ali, Tahir; Hameed, Shahid

    2017-01-01

    Cu2 + and Fe3 + complexes of three flavonoids (morin or mo, quercetin or quer and primuletin or prim) were synthesized with the objective of improving antioxidant capacities of flavonoids. The radical scavenging activities of pure flavonoids and their metal complexes were assayed to monitor their tendencies towards sequestering of radicals at physiological conditions. The scavenger potencies of metal-flavonoid complexes were significantly higher than those of the parent flavonoids. Further, influence of the solvent polarity on the radical capturing by flavonoids and their metal complexes was in favor for the polar solvent. Fe3 +-prim displayed its radical scavenging ability via up gradation of CAT and SOD activities in in-vivo antioxidant assays.

  13. Structural-Phase States of Fe-Cu and Fe-Ag Bimetallic Particles Produced by Electric Explosion of Two Wires

    Science.gov (United States)

    Lerner, M. I.; Bakina, O. V.; Pervikov, A. V.; Glazkova, E. A.; Lozhkomoev, A. S.; Vorozhtsov, A. B.

    2018-05-01

    X-ray phase analysis, transmission electron microscopy, and X-ray microanalysis were used to examine the structural-phase states of Fe-Cu and Fe-Ag bimetallic nanoparticles. The nanoparticles were obtained by the electric explosion of two twisted metal wires in argon atmosphere. It was demonstrated that the nanoparticles have the structure of Janus particles. Presence of the Janus particle structure in the samples indicates formation of binary melt under conditions of combined electric explosion of two wires. Phases based on supersaturated solid solutions were not found in the examined samples. The data obtained allow arguing that it is possible to achieve uniform mixing of the two-wire explosion products under the described experiment conditions.

  14. Modeling copper precipitation hardening and embrittlement in a dilute Fe-0.3at.%Cu alloy under neutron irradiation

    Science.gov (United States)

    Bai, Xian-Ming; Ke, Huibin; Zhang, Yongfeng; Spencer, Benjamin W.

    2017-11-01

    Neutron irradiation in light water reactors can induce precipitation of nanometer sized Cu clusters in reactor pressure vessel steels. The Cu precipitates impede dislocation gliding, leading to an increase in yield strength (hardening) and an upward shift of ductile-to-brittle transition temperature (embrittlement). In this work, cluster dynamics modeling is used to model the entire Cu precipitation process (nucleation, growth, and coarsening) in a Fe-0.3at.%Cu alloy under neutron irradiation at 300°C based on the homogenous nucleation mechanism. The evolution of the Cu cluster number density and mean radius predicted by the modeling agrees well with experimental data reported in literature for the same alloy under the same irradiation conditions. The predicted precipitation kinetics is used as input for a dispersed barrier hardening model to correlate the microstructural evolution with the radiation hardening and embrittlement in this alloy. The predicted radiation hardening agrees well with the mechanical test results in the literature. Limitations of the model and areas for future improvement are also discussed in this work.

  15. 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.

  16. Magnetic ageing study of high and medium permeability nanocrystalline FeSiCuNbB alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lekdim, Atef, E-mail: atef.lekdim@univ-lyon1.fr; Morel, Laurent; Raulet, Marie-Ange

    2017-04-15

    increasing the energy efficiency is one of the most important issues in modern power electronic systems. In aircraft applications, the energy efficiency must be associated with a maximum reduction of mass and volume, so a high components compactness. A consequence from this compactness is the increase of operating temperature. Thus, the magnetic materials used in these applications, have to work at high temperature. It raises the question of the thermal ageing problem. The reliability of these components operating at this condition becomes a real problem which deserves serious interest. Our work takes part in this context by studying the magnetic material thermal ageing. The nanocrystalline materials are getting more and more used in power electronic applications. Main advantages of nanocrystalline materials compared to ferrite are: high saturation flux density of almost 1.25 T and low dynamic losses for low and medium frequencies. The nanocrystalline Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 15.5}B{sub 7} alloys have been chosen in our aging study. This study is based on monitoring the magnetic characteristics for several continuous thermal ageing (100, 150, 200 and 240 °C). An important experimental work of magnetic characterization is being done following a specific monitoring protocol. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena. - Highlights: • The magnetic ageing of the nanocrystalline materials is related to their annealing. • The degradations with ageing are not related to a change of the grain size diameter. • The amount of anisotropies introduced with ageing depends just on ageing conditions.

  17. On the electronic structure and thermoelectric properties of BiTeBr and BiTeI single crystals and of BiTeI with the addition of BiI3 and CuI

    International Nuclear Information System (INIS)

    Kulbachinskii, Vladimir A.; Kytin, Vladimir G.; Kudryashov, Alexey A.; Kuznetsov, Alexei N.; Shevelkov, Andrei V.

    2012-01-01

    The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering model. Because of larger thermopower BiTeBr exhibits a twice higher thermoelectric figure-of-merit near room temperature, ZT=0.17, compared to BiTeI. The addition of 1 mass% of BiI 3 or CuI to BiTeI decreases the mobility of electrons by two orders of magnitude, leading to significantly lower electrical conductivity, but at the same time effectively reduces the thermal conductivity. The prospects of further enhancing the thermoelectric efficiency are briefly discussed. - Graphical abstract: View of the crystal structure of BiTeBr is shown in the figure The optimized crystal structures show a tendency for the Bi–X (X=Br, I) bond elongation compared to the Bi–Te one. The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin–orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering

  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)

    Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M.I.; Hou, M.

    2009-01-01

    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. Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

    Science.gov (United States)

    Castin, N.; Malerba, L.; Bonny, G.; Pascuet, M. I.; Hou, M.

    2009-09-01

    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.

  20. Modelling radiation-induced phase changes in binary FeCu and ternary FeCuNi alloys using an artificial intelligence-based atomistic kinetic Monte Carlo approach

    Energy Technology Data Exchange (ETDEWEB)

    Castin, N. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium); Malerba, L. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium)], E-mail: lmalerba@sckcen.be; Bonny, G. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); Laboratory of Theoretical Physics, Universiteit Gent, Proeftuinstraat 86, B-9000 Gent (Belgium); Pascuet, M.I. [Structural Materials Group, Nuclear Materials Science Institute, Kernenergie Centre d' Etude de l' Energie Nucleaire (SCK CEN), Studiecentrum voor, Boeretang 200, 2400 Mol (Belgium); CAC-CNEA, Departamento de Materiales, Avda. Gral. Paz 1499, 1650 San Martin, Pcia. Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917, 1033 Buenos Aires (Argentina); Hou, M. [Physique des Solides Irradies et des Nanostructures (PSIN), Universite Libre de Bruxelles (ULB), Boulevard du Triomphe CP234, 1050 Brussels (Belgium)

    2009-09-15

    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.

  1. Study of the ternary alloy systems Al-Ni-Fe and Al-Cu-Ru with special regard to quasicrystalline phases

    International Nuclear Information System (INIS)

    Lemmerz, U.

    1996-07-01

    Two ternary alloy-systems, the Al-Ni-Fe system and the Al-Cu-Ru system were studied with special regard to quasicrystalline phases. Isothermal sections were established in both systems in the stoichiometric area of the quasicrystalline phase. In the Al-Ni-Fe system a new stable decagonal phase was found. Its stoichiometric range is very small around Al 71.6 Ni 23.0 Fe 5.4 . The temperature range in which it is stable lies between 847 and 930 C. The decagonal phase undergoes a eutectoid reaction to the three crystalline phases Al 3 Ni 2 , Al 3 Ni and Al 13 Fe 4 at 847 C. It melts peritectically at 930 C forming Al 13 Fe 4 , Al 3 Ni 2 and a liquid. The investigations in the Al-Cu-Ru system concentrated on the phase equilibria between the icosahedral phase and its neighbouring phases in a temperature range between 600 and 1000 C. The icosahedral phase was observed in the whole temperature range. The investigated stoichiometric area extends down to Al contents of 45%, which allows the fields of existence to be determined for the ternary phases α-AlCuRu, the icosahedral phase and Al 7 Cu 2 Ru. Binary phases were determined down to the upper (high Al content) border of AlRu. No hitherto unknown phase was observed in the investigated area. Rietveld analyses were carried out on α-AlCuRu and Al 7 Cu 2 Ru showing some discrepancies from the α-AlMnSi structure taken as a base for α-AlCuRu and confirming the Al 7 Cu 2 Fe structure for Al 7 Cu 2 Ru. (orig.)

  2. Atomic level structural modulation during the structural relaxation and its effect on magnetic properties of Fe81Si4B10P4Cu1 nanocrystalline alloy

    Science.gov (United States)

    Cao, C. C.; Zhu, L.; Meng, Y.; Zhai, X. B.; Wang, Y. G.

    2018-06-01

    The evolution of local structure and defects in the Fe81Si4B10P4Cu1 amorphous alloy during the structural relaxation has been investigated by Mössbauer spectroscopy, positron annihilation lifetime spectroscopy and transmission electron microscopy to explore their effects on magnetic properties of the nanocrystalline. The atomic rearrangements at the early stage of the structural relaxation cause the density increase of the amorphous matrix, but the subsequent atomic rearrangements contribute to the transformation of Fe3B-like atomic arrangements to FeB-like ones with the temperature increasing. As the structural relaxation processes, the released Fe atoms both from Fe3B- and Fe3P-like atomic arrangements result in the formation of new Fe clusters and the increase of Fe-Fe coordination number in the existing Fe clusters and the nucleation sites for α-Fe gradually increase, both of which promote the crystallization. However, the homogeneity of amorphous matrix will be finally destroyed under excessive relaxation temperature, which coarsens nanograins during the crystallization instead. Therefore, soft magnetic properties of the Fe81Si4B10P4Cu1 nanocrystalline alloy can be improved by pre-annealing the amorphous precursor at an appropriate temperature due to the atomic level structural optimization.

  3. The coercivity mechanism of sintered SM(Co_b_a_lFe_0_._2_4_5Cu_0_._0_7Zr_0_._0_2)_7_._8 permanent magnets with different isothermal annealing time

    International Nuclear Information System (INIS)

    Sun, Wei; Zhu, Minggang; Guo, Zhaohui; Fang, Yikun; Li, Wei

    2015-01-01

    Precipitation-hardened 2:17-type SmCo permanent magnet has attracted much attention due to its high Curie temperature and excellent magnetic properties. Sm(Co_b_a_lFe_0_._2_4_5Cu_0_._0_7Zr_0_._0_2)_7_._8 (at%) sintered magnets with high remanence (B_r ~1.15 T) were prepared using a traditional powder metallurgy method. The intrinsic coercivity H_c_j of the magnets was increased from 429 to 994 kA m"−"1 with isothermal annealing time increasing from 10 to 40 h, which is different from the phenomenon that increasing aging time leads to a reduced coercivity mentioned in the Ref. [16]. In consideration of rarely report about the microstructure of the final magnet isothermally annealed for 40 h, we have tried to originally analyze the relationship between the microstructure and the magnetic properties. Besides, the lattice constants of sintered Sm(Co_b_a_lFe_0_._2_4_5Cu_0_._0_7Zr_0_._0_2)_7_._8 permanent magnet isothermally annealed for 40 h have been given by indexing the HRTEM results including the selected area electron diffraction (SAED) and HRTEM images.

  4. Indolenine meso-substituted dibenzotetraaza[14]annulene and its coordination chemistry toward the transition metal ions Mn(III), Fe(III), Co(II), Ni(II), Cu(II), and Pd(II).

    Science.gov (United States)

    Khaledi, Hamid; Olmstead, Marilyn M; Ali, Hapipah Mohd; Thomas, Noel F

    2013-02-18

    A new dibenzotetraaza[14]annulene bearing two 3,3-dimethylindolenine fragments at the meso positions (LH(2)), has been synthesized through a nontemplate method. X-ray crystallography shows that the whole molecule is planar. The basicity of the indolenine ring permits the macrocycle to be protonated external to the core and form LH(4)(2+)·2Cl(-). Yet another structural modification having strong C-H···π interactions was found in the chloroform solvate of LH(2). The latter two modifications are accompanied by a degree of nonplanar distortion. The antiaromatic core of the macrocycle can accommodate a number of metal ions, Mn(III), Fe(III), Co(II), Ni(II) and Cu(II), to form complexes of [Mn(L)Br], [Mn(L)Cl], [Fe(LH(2))Cl(2)](+)·Cl(-), [Co(L)], [Ni(L)], and [Cu(L)]. In addition, the reaction of LH(2) with the larger Pd(II) ion leads to the formation of [Pd(2)(LH(2))(2)(OAc)(4)] wherein the macrocycle acts as a semiflexible ditopic ligand to coordinate pairs of metal ions via its indolenine N atoms into dinuclear metallocycles. The compounds LH(2), [Co(L)], and [Ni(L)] are isostructural and feature close π-stacking as well as linear chain arrangements in the case of the metal complexes. Variable temperature magnetic susceptibility measurements showed thermally induced paramagnetism in [Ni(L)].

  5. 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

  6. 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.

  7. Effect of dispersion hardening on impact resistance of EN AC-AlSi12Cu2Fe silumin

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2009-04-01

    Full Text Available Development of modern technology have generated supply of better and better, more resistant structural materials not attainable earlier.Weight of metal structures is of a great importance, and as a consequence, also weight of materials used for a given structure. More often, for metal structures are used lightweight metals and their alloys, from which aluminum and its alloys have become the most widespread. These alloys, based on Al-Si equilibrium system, contain additional constituents (e.g.: Mg, Cu enabling, except modification,improvement of mechanical properties obtained in result of heat treatment. The paper presents an effect of modification process and heat treatment on impact resistance of EN AC-AlSi12Cu2Fe alloy. Solutioning and ageing temperatures were selected on base of registered curves of the ATD method. For the neareutectic EN AC-AlSi12Cu2Fe silumin one obtained growth of the impact resistance both due to performed modification treatment and performed heat treatments of the alloy.

  8. Elimination of nitrate in secondary effluent of wastewater treatment plants by Fe0 and Pd-Cu/diatomite

    Directory of Open Access Journals (Sweden)

    Yupan Yun

    2018-03-01

    Full Text Available Because total nitrogen (TN, in which nitrate (NO3– is dominant in the effluent of most wastewater treatment plants, cannot meet the requirement of Chinese wastewater discharge standard (<15 mg/L, NO3– elimination has attracted considerable attention. In this research, the novel diatomite-supported palladium-copper catalyst (Pd-Cu/diatomite with zero-valent iron (Fe0 was tried to use for catalytic reduction of nitrate in wastewater. Firstly, specific operational conditions (such as mass ratio of Pd:Cu, catalyst amounts, reaction time and pH of solution were optimized for nitrate reduction in artificial solution. Secondly, the selected optimal conditions were further employed for nitrate elimination of real effluent of a wastewater treatment plant in Beijing, China. Results showed that 67% of nitrate removal and 62% of N2 selectivity could be obtained under the following conditions: 5 g/L Fe0, 3:1 mass ratio (Pd:Cu, 4 g/L catalyst, 2 h reaction time and pH 4.3. Finally, the mechanism of catalytic nitrate reduction was also proposed.

  9. Influence of shape and thickness on the levitation force of YBaCuO bulk HTS over a NdFeB guideway

    International Nuclear Information System (INIS)

    Ren Zhongyou; Wang Jiasu; Wang Suyu; Jiang He; Zhu Min; Wang Xiaorong; Song Honghai

    2003-01-01

    Levitation forces of YBaCuO bulk high temperature superconductors (HTS) with different shape and size over a NdFeB guideway were studied. Here, the concentrating magnetic field of the NdFeB guideway was 1.2 T, and the YBaCuO bulk HTSs include three cylindrical samples with different diameter and thickness and one hexagonal sample. The maximum levitation force is as high as 85.3 N at a gap of 5 mm between the bottom surface of YBaCuO bulk HTS and the top surface of the NdFeB guideway, where the applied magnetic field is about 0.8 T. The results show that the shape and the size have large influences on the levitation force of YBaCuO bulk HTSs

  10. Structure and soft magnetic properties of Fe-Si-B-P-Cu nanocrystalline alloys with minor Mn addition

    Directory of Open Access Journals (Sweden)

    Xingjie Jia

    2018-05-01

    Full Text Available Addition of minor Mn effectively improves the amorphous-forming ability and thermal stability of the Fe85Si2B8P4Cu1 alloy. With increasing the Mn content from 0 to 3 at.%, the critical thickness for amorphous formation and onset temperature of the primary crystallization increase from 14 μm and 659 K to 27 μm and 668 K, respectively. The fine nanocrystalline structure with α-Fe grains in size (D of < 20 nm was obtained for the annealed amorphous alloys, which show excellent soft magnetic properties. The alloying of Mn reduces the coercivity (Hc by decreasing the D value and widens the optimum annealing temperature range for obtaining low Hc, although the saturation magnetic flux density (Bs is decreased slightly. The Fe83Mn2Si2B8P4Cu1 nanocrystalline alloy possesses fine structure with a D of ∼17.5 nm, and exhibits a high Bs of ∼1.75 T and a low Hc of ∼5.9 A/m. The mechanism related to the alloying effects on the structure and magnetic properties was discussed in term of the crystallization activation energy.

  11. Structure and soft magnetic properties of Fe-Si-B-P-Cu nanocrystalline alloys with minor Mn addition

    Science.gov (United States)

    Jia, Xingjie; Li, Yanhui; Wu, Licheng; Zhang, Wei

    2018-05-01

    Addition of minor Mn effectively improves the amorphous-forming ability and thermal stability of the Fe85Si2B8P4Cu1 alloy. With increasing the Mn content from 0 to 3 at.%, the critical thickness for amorphous formation and onset temperature of the primary crystallization increase from 14 μm and 659 K to 27 μm and 668 K, respectively. The fine nanocrystalline structure with α-Fe grains in size (D) of < 20 nm was obtained for the annealed amorphous alloys, which show excellent soft magnetic properties. The alloying of Mn reduces the coercivity (Hc) by decreasing the D value and widens the optimum annealing temperature range for obtaining low Hc, although the saturation magnetic flux density (Bs) is decreased slightly. The Fe83Mn2Si2B8P4Cu1 nanocrystalline alloy possesses fine structure with a D of ˜17.5 nm, and exhibits a high Bs of ˜1.75 T and a low Hc of ˜5.9 A/m. The mechanism related to the alloying effects on the structure and magnetic properties was discussed in term of the crystallization activation energy.

  12. Cation distribution in CuFe{sub 2}O{sub 4} nanoparticles: Effects of Ni doping on magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Thanh, Nguyen Kim; Loan, To Thanh, E-mail: totloan@itims.edu.vn; Anh, Luong Ngoc; Duong, Nguyen Phuc; Hien, Than Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, Hanoi 100000 (Viet Nam); Soontaranon, Siriwat; Thammajak, Nirawat [Synchrotron Light Research Institute, 111 University Avenue, Suranaree, Muang, Nakhon Ratchasima 30000 (Thailand)

    2016-10-14

    The Cu{sub 1−x}Ni{sub x}Fe{sub 2}O{sub 4} nanoparticles (with x = 0, 0.3, 0.5, 0.7, and 1) were synthesized by using spray co-precipitation method at annealing temperature T{sub a} = 900 °C in air for 5 h. The crystal structure, microstructure, oxidation state, and magnetic properties of the samples were characterized by using X-ray diffraction, synchrotron X-ray diffraction, scanning electron microscopy, X-ray absorption spectroscopy, and vibrating sample magnetometer. It was shown that all the samples have cubic structure. Lattice constant and grain size decrease, while the Curie temperature T{sub C} increases with increasing of Ni{sup 2+} content. A small amount of Fe{sup 2+} was found in all the samples. Cation distribution was determined by using a combination of magnetization measurements, extended X-ray absorption fine structure analysis, and Rietveld refinement from synchrotron X-ray diffraction data. It was indicated that Ni{sup 2+} ions occupy in octahedral site only, while Cu{sup 2+} ions distribute in both tetrahedral and octahedral sites. The variation of magnetic parameters is discussed based on Ni{sup 2+} concentration, grain size, the cation distribution, surface effect, and the presence of Fe{sup 2+} ion in the samples.

  13. Chelation of Cu(II, Zn(II, and Fe(II by Tannin Constituents of Selected Edible Nuts

    Directory of Open Access Journals (Sweden)

    Magdalena Karamać

    2009-12-01

    Full Text Available 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 of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II. The Fe(II complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II by ~90%. The capacity to chelate Zn(II was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II, whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II chelation took place at the levels tested.

  14. The mechanism of degradation of bisphenol A using the magnetically separable CuFe_2O_4/peroxymonosulfate heterogeneous oxidation process

    International Nuclear Information System (INIS)

    Xu, Yin; Ai, Jia; Zhang, Hui

    2016-01-01

    Highlights: • Copper ferrite (CuFe_2O_4) was fabricated and utilized in heterogeneous PMS process. • The influence of reaction parameters for the mineralization of BPA were evaluated. • Possible reaction mechanism and the stability of CuFe_2O_4 were investigated. • Surface bound radicals (mainly ·OH) may be responsible for the BPA degradation. - Abstract: The removal of bisphenol A (BPA) in aqueous solution by an oxidation process involving peroxymonosulfate (PMS) activated by CuFe_2O_4 magnetic nanoparticles (MNPs) is reported herein. The effects of PMS concentration, CuFe_2O_4 dosage, initial pH, initial BPA concentration, catalyst addition mode, and anions (Cl"−, F"−, ClO_4"− and H_2PO_4"−) on BPA degradation were investigated. Results indicate that nearly complete removal of BPA (50 mg/L) within 60 min and 84.0% TOC removal in 120 min could be achieved at neutral pH by using 0.6 g/L CuFe_2O_4 MNPs and 0.3 g/L PMS. The generation of reactive radicals (mainly hydroxyl radicals) was confirmed using electron paramagnetic resonance (EPR). Possible mechanisms on the radical generation from CuFe_2O_4/PMS system are proposed based on the results of radical identification tests and XPS analysis. The lack of inhibition of the reaction by free radical scavengers such as methanol and tert-butyl alcohol suggests that these species may not be generated in the bulk solution, and methylene blue probe experiments confirm that this process does not involve free radical generation. Surface-bound, rather than free radicals generated by a surface catalyzed-redox cycle involving both Fe(III) and Cu(II), are postulated to be responsible for the mineralization of bisphenol A.

  15. Conventional and microwave combustion synthesis of optomagnetic CuFe2O4 nanoparticles for hyperthermia studies

    Science.gov (United States)

    Kombaiah, K.; Vijaya, J. Judith; Kennedy, L. John; Bououdina, M.; Al-Najar, Basma

    2018-04-01

    Nanosized copper ferrite (CuFe2O4) nanoparticles have been prepared by conventional (CCM) and microwave (MCM) combustion methods using Hibiscus rosa sinensis plant extract as a fuel. XRD and rietveld analysis confirmed the formation of single cubic phase and with crystallite size varying from 25 to 62 nm owing to grain growth after calcination. FT-IR analysis confirms the modes of the cubic CuFe2O4 phase, due to the stretching and bending vibrations. Spherical shaped particles are observed by scanning electron microscopy and the average particle size is found to be in the range of 50-200 nm. The chemical composition is confirmed by energy dispersive X-ray analysis. The optical band gap energy estimated using Kubelka-Munk function with the help of UV-Visible diffused reflectance spectroscopy, is found to be 2.34 and 2.22 eV for CCM and MCM respectively. Photoluminescence analysis indicates that both samples absorb light in the UV-visible region and exhibit emissions at 360, 376, and 412 nm. Magnetic measurements indicate a ferromagnetic behavior, where both magnetic properties very much influenced by the preparation method and calcination temperature: both saturation magnetization and coercivity are found higher when using CCM and MCM; from 29.40 to 34.09 emu/g while almost double from 224.4 to 432.2 Oe. The observed changes in physical properties are mainly associated with crystallinity, particle size, better chemical homogeneity, and cations distribution among tetrahedral/octahedral sites. The maximum specific absorption rate obtained was 14.63 W/g, which can be considered suitable and favorable for magnetic hyperthermia. This study highlighted the benefits of green synthesis of CuFe2O4 nanoparticles providing better magnetic properties for the platform of hyperthermia application.

  16. Investigation on the formation of Cu-Fe nano crystalline super-saturated solid solution developed by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, M., E-mail: m.mojtahedi@gmail.com [School of Materials Science and Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Goodarzi, M.; Aboutalebi, M.R. [School of Materials Science and Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Ghaffari, M. [Department of Electrical and Electronics Engineering, UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Soleimanian, V. [Department of Physics, Faculty of Science, Shahrekord University, P.O. Box 115, Shahrekord (Iran, Islamic Republic of)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer The deformation of the mechanically alloyed Cu-Fe powder is anisotropic. Black-Right-Pointing-Pointer The Rietveld method is more proper and results in smaller crystallite size than the Scherer and Williamson-Hall methods. Black-Right-Pointing-Pointer A dual phase super saturated solid solution achieved after 96 h of milling of the mixtures with 30, 50 and 70 wt.% of Iron. Black-Right-Pointing-Pointer A final proportion of approximately 85% FCC and 15% BCC structure obtained in all of the applied compositions. - Abstract: In this study, the formation of super saturated solid solution in the binary Cu-Fe system was investigated. Three powder blends with 30, 50 and 70 wt.% of Fe were milled for different times to 96 h. The variations of lattice parameter and inter-planar spacing were calculated and analyzed using X-ray diffraction analysis (XDA). The anisotropy of lattice deformation in the FCC phase was studied and the obtained results were compared to milled pure Cu powder. Furthermore, crystallite size was calculated using Scherer formula in comparison with Rietveld full profile refinement method. Considering the previous studies about the formation of non-equilibrium FCC and BCC phases, the phase evolution has been discussed and the proportion of each phase was calculated using Rietveld refinement method. Supplementary studies on the evolution of microstructure and formation of solid solution were carried out using high resolution transmission electron microscopy (HRTEM). Finally, high angle annular dark field (HAADF) imaging was utilized to find out the level of homogeneity in the resulting phases. While true alloying takes place in each phase, the final structure consists of both FCC and BCC nano-crystallites.

  17. Fracture toughness and flexural strength of Sm(Co,Fe,Cu,Zr){sub 7-8} magnetic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Libo. E-mail: ren@me.udel.edu; Hadjipanayis, George C.; Parvizi-Majidi, Azar

    2003-02-01

    This paper presents the results of a parametric investigation of the strength and fracture toughness of Sm{sub 2}Co{sub 17} type permanent magnets in the Sm(Co,Fe,Cu,Zr){sub 7-8} family of alloys. The strength and fracture toughness of the as-received materials were characterized as a function of temperature, loading direction, and magnetization. Since these magnets are candidates for applications with service temperatures up to 450 deg. C, the effect of thermal exposure on the mechanical properties was determined by characterizing the properties after a thermal treatment of 40 h at 450 deg. C00.

  18. Fracture toughness and flexural strength of Sm(Co,Fe,Cu,Zr)7-8 magnetic alloys

    International Nuclear Information System (INIS)

    Ren, Libo.; Hadjipanayis, George C.; Parvizi-Majidi, Azar

    2003-01-01

    This paper presents the results of a parametric investigation of the strength and fracture toughness of Sm 2 Co 17 type permanent magnets in the Sm(Co,Fe,Cu,Zr) 7-8 family of alloys. The strength and fracture toughness of the as-received materials were characterized as a function of temperature, loading direction, and magnetization. Since these magnets are candidates for applications with service temperatures up to 450 deg. C, the effect of thermal exposure on the mechanical properties was determined by characterizing the properties after a thermal treatment of 40 h at 450 deg. C

  19. Levels determination of heavy elements (Fe, Cu, Zn, Pb and Hg) in sword fish caught from the bay of Ghazaouet

    International Nuclear Information System (INIS)

    Chalabi, A.; Malek, M.; Ghomari, M.; Benamar, M.A.; Tchantchane, A.; Azbouche, A.; Toumert, I.; Benouali, N.; Tobbeche, S. , Algiers; Algeria)

    1993-04-01

    The nuclear technics 'PIXE' and 'XRF', were used for heavy metals analysis (Fe, Cu, Zn, Pb, and Hg), in sword fish (xiphias Gladius) caught in Ghazaouet bay. Muscles, liver and gonads were analysed. The methods gave similar results. A bioaccumulation phenomenon was observed except for Hg. The high amount of concentrations found liver, especially in the case of confirms that liver is a storage organ. The high levels of Zn seem to be due to the industrial wastes from the electrolyte plant in the region. All values were lower than the admissible norms

  20. Measurement of the thermoelectric properties of quasicrystalline AlPdRe and AlCuFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M L; LeGault, S; Stroud, R M; Tritt, T M

    1997-07-01

    The authors report the measurement of the thermal conductivity, electrical resistivity, and thermoelectric power on two quasicrystalline compounds, Al{sub 70}Pd{sub 20}Re{sub 10} and Al{sub 62.5}Cu{sub 25}Fe{sub 12.5}. These materials are found to possess a thermal conductivity of order 1 W/m{center{underscore}dot}K, while retaining their semimetallic conductivity. These features coupled with moderately large thermopowers, up to 55 {micro}V/K, imply that the general class of quasicrystalline compounds warrants careful investigation for their potential as new thermoelectric materials.

  1. Investigation of cellular microstructure and enhanced coercivity in sputtered Sm2(CoCuFeZr)17 film

    International Nuclear Information System (INIS)

    Bhatt, Ranu; Schütz, G.; Bhatt, Pramod

    2014-01-01

    We have investigated the effect of annealing temperature on the microstructure and magnetic properties of Sm 2 (CoCuFeZr) 17 films prepared using ion beam sputtering at room temperature. The as-deposited film shows randomly oriented polycrystalline grains and exhibits small coercivity (H C ) of 0.04 T at room temperature. Post annealing of these films at 700 °C under Ar atmosphere shows significant changes in the microstructure transforming it to the development of cellular growth, concomitant with enhanced coercivity up to 1.3 T. The enhanced coercivity is explained using the domain wall pinning mechanism

  2. Mean charge states of MeV/u Fe, Co, Ni and Cu ions in Au and Bi solid targets

    International Nuclear Information System (INIS)

    Ciortea, C.; Dumitriu, D.E.; Enescu, S.E.; Enulescu, A.; Fluerasu, D.; Piticu, I.; Szilagyi, Z.S.

    2001-01-01

    The average charge states of 0.1 - 1.5 MeV/u Fe, Co, Ni, and Cu ions in solid Au and Bi targets have been determined by estimating the mean numbers of outer-shell spectator vacancies during the K-vacancy decay. The latter quantities were obtained from the yield and energy shifts of the K α , β X-rays, by comparing with calculations in the independent electron approximation. The reported equilibrium charges, mostly characteristic for the inside of the target, are in fairly agreement with Nikolaev and Dmitriev semi-empirical formula. (authors)

  3. 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.

  4. Nd-Fe-B-Cu hot deformation processing: a comparison of deformation modes, microstructural development and magnetic properties

    International Nuclear Information System (INIS)

    Ferrante, M.; Sinka, V.; Assis, O.B.G.; Oliveira, I. de; Freitas, E. de

    1996-01-01

    Due to its relative simplicity and low cost the hot deformation of Nd-Fe-B ingots is rapidly reaching the status of a valid alternative to sintering. Among the possible deformation modes, pressing, rolling and forging are perhaps the most successful. This paper describes the research programme undertaken so far, by discussing the relationship between deformation mode, microstructure and magnetic properties of magnets produced by hot deformation mode, microstructure and magnetic properties of magnets produced by hot deformation of a number of Nd-fe-B-Cu alloys. Microstructural observation showed that both pressed and forged samples are characterized by a heterogeneous microstructure and from magnetic measurements it was concluded that magnetic properties differ when taken in the center or in the periphery of the sample. On the other hand roller magnets were homogeneous both in terms of microstructure and magnetic properties, and interpretations of the mechanisms of texture development and of microstructural development of hot deformed magnets is put forward. (author)

  5. Ionic configuration of copper ferrimanganites Cu 0.5Mn xFe 2.5- xO 4

    Science.gov (United States)

    Lenglet, M.; Kasperek, J.; Hannoyer, B.; Lopitaux, J.; d'Huysser, A.; Tellier, J. C.

    1992-06-01

    Mössbauer spectrometry, neutron diffraction, XANES, and XPS have led to the determination of the cation distributions of the system Cu 0.5Mn xFe 2.5- xO 4 (0≤ x≤1.5). The three cations are present in both tetrahedral and octahedral sites, and the relative number of Fe ions on A- and B-sites remains nearly constant in the whole range of x. It appears that for x≤0.5 manganese is divalent and copper is in its two oxidation states. For x>0.5 copper and iron are respectively divalent and trivalent; the manganese is in +2 and +3 oxydation states.

  6. Lateral electric-field control of giant magnetoresistance in Co/Cu/Fe/BaTiO{sub 3} multiferroic heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Savitha Pillai, S.; Kojima, H.; Itoh, M.; Taniyama, T., E-mail: taniyama.t.aa@m.titech.ac.jp [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503 (Japan)

    2015-08-17

    We report lateral electric-field-driven sizable changes in the magnetoresistance of Co/Cu/Fe tri-layered wires on BaTiO{sub 3} single crystal. While the observed change is marginal in the tetragonal phase of BaTiO{sub 3}, 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 BaTiO{sub 3}. The contrasting results for the different phases of BaTiO{sub 3} are discussed, associated with the distinct aspects of the ferroelectric polarization switching processes in each phase.

  7. Lateral electric-field control of giant magnetoresistance in Co/Cu/Fe/BaTiO3 multiferroic heterostructure

    International Nuclear Information System (INIS)

    Savitha Pillai, S.; Kojima, H.; Itoh, M.; Taniyama, T.

    2015-01-01

    We report lateral electric-field-driven sizable changes in the magnetoresistance of Co/Cu/Fe tri-layered wires on BaTiO 3 single crystal. While the observed change is marginal in the tetragonal phase of BaTiO 3 , 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 BaTiO 3 . The contrasting results for the different phases of BaTiO 3 are discussed, associated with the distinct aspects of the ferroelectric polarization switching processes in each phase

  8. Lateral electric-field control of giant magnetoresistance in Co/Cu/Fe/BaTiO3 multiferroic heterostructure

    Science.gov (United States)

    Savitha Pillai, S.; Kojima, H.; Itoh, M.; Taniyama, T.

    2015-08-01

    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.

  9. Immobilization of [Cu(bpy)2]Br2 complex onto a glassy carbon electrode modified with alpha-SiMo12O40(4-) and single walled carbon nanotubes: application to nanomolar detection of hydrogen peroxide and bromate.

    Science.gov (United States)

    Salimi, Abdollah; Korani, Aazam; Hallaj, Rahman; Khoshnavazi, Roshan; Hadadzadeh, Hasan

    2009-03-02

    A simple procedure has been used for preparation of modified glassy carbon electrode with carbon nanotubes and copper complex. Copper complex [Cu(bpy)(2)]Br(2) was immobilized onto glassy carbon (GC) electrode modified with silicomolybdate, alpha-SiMo(12)O(40)(4-) and single walled carbon nanotubes (SWCNTs). Copper complex and silicomolybdate irreversibly and strongly adsorbed onto GC electrode modified with CNTs. Electrostatic interactions between polyoxometalates (POMs) anions and Cu-complex, cations mentioned as an effective method for fabrication of three-dimensional structures. The modified electrode shows three reversible redox couples for polyoxometalate and one redox couple for Cu-complex at wide range of pH values. The electrochemical behavior, stability and electron transfer kinetics of the adsorbed redox couples were investigated using cyclic voltammetry. Due to electrostatic interaction, copper complex immobilized onto GC/CNTs/alpha-SiMo(12)O(40)(4-) electrode shows more stable voltammetric response compared to GC/CNTs/Cu-complex modified electrode. In comparison to GC/CNTs/Cu-complex the GC/CNTs/alpha-SiMo(12)O(40)(4-) modified electrodes shows excellent electrocatalytic activity toward reduction H(2)O(2) and BrO(3)(-) at more reduced overpotential. The catalytic rate constants for catalytic reduction hydrogen peroxide and bromate were 4.5(+/-0.2)x10(3) M(-1) s(-1) and 3.0(+/-0.10)x10(3) M(-1) s(-1), respectively. The hydrodynamic amperommetry technique at 0.08 V was used for detection of nanomolar concentration of hydrogen peroxide and bromate. Detection limit, sensitivity and linear concentration range proposed sensor for bromate and hydrogen peroxide detection were 1.1 nM and 6.7 nA nM(-1), 10 nM-20 microM, 1 nM, 5.5 nA nM(-1) and 10 nM-18 microM, respectively.

  10. The Effects of Fe-Particles on the Tensile Properties of Al-Si-Cu Alloys

    Directory of Open Access Journals (Sweden)

    Anton Bjurenstedt

    2016-12-01

    Full Text Available The effect of Fe-rich particles has been a topic for discussion in the aluminum casting industry because of the negative impact they exert on the mechanical properties. However, there are still contradictions on the effects of various morphologies of Fe-particles. In this study, microstructural characterization of tensile tested samples has been performed to reveal how unmodified and modified Fe-rich particles impact on the tensile behavior. Analysis of additions of Fe modifiers such as Mn and Cr, showed higher amounts of primary Fe-rich particles (sludge with increased porosity and, as result, degraded tensile properties. From the fracture analysis of tensile tested hot isostatic pressed (HIPed samples it could be concluded that the mechanical properties were mainly governed by the Fe-rich particles, which were fracturing through cleavage, not by the porosity.

  11. Effect of Ti content on structure and properties of Al2CrFeNiCoCuTix high-entropy alloy coatings

    International Nuclear Information System (INIS)

    Qiu, X.W.; Zhang, Y.P.; Liu, C.G.

    2014-01-01

    Highlights: • Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. • Al 2 CrFeNiCoCuTi x coatings show excellent corrosion resistance and wear resistance. • Al 2 CrFeNiCoCuTi x coatings play a good protective effect on Q235 steel. • Ti element promotes the formation of a BCC structure in a certain extent. -- Abstract: The Al 2 CrFeNiCoCuTi x high-entropy alloy coatings were prepared by laser cladding. The structure, hardness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical microscope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al 2 CrFeNiCoCuTi x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combination; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al 2 CrFeNiCoCuTi x high-entropy alloy coatings is reduced by 1–2 orders of magnitude, the free-corrosion potential is more “positive”. With the increasing of Ti content, the corrosion resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings enhanced in 0.5 mol/L HNO 3 solution. Compared with Q235 steel, the relative wear resistance of Al 2 CrFeCoCuNiTi x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Magnetization loop shows that, Ti 0.0 high-entropy alloy is a kind of soft magnetic materials

  12. Effect of mineral-enriched diet and medicinal herbs on Fe, Mn, Zn, and Cu uptake in chicken

    Directory of Open Access Journals (Sweden)

    Stef Ducu

    2012-03-01

    Full Text Available Abstract Background The goal of our study was to evaluate the effects of different medicinal herbs rich in polyphenol (Lemon balm, Sage, St. John's wort and Small-flowered Willowherb used as dietary supplements on bioaccumulation of some essential metals (Fe, Mn, Zn and Cu in different chicken meats (liver, legs and breast. Results In different type of chicken meats (liver, legs and breast from chickens fed with diets enriched in minerals and medicinal herbs, beneficial metals (Fe, Mn, Zn and Cu were analysed by flame atomic absorption spectrometry. Fe is the predominant metal in liver and Zn is the predominant metal in legs and breast chicken meats. The addition of metal salts in the feed influences the accumulations of all metals in the liver, legs and breast chicken meat with specific difference to the type of metal and meat. The greatest influences were observed in legs meat for Fe and Mn. Under the influence of polyphenol-rich medicinal herbs, accumulation of metals in the liver, legs and breast chicken meat presents specific differences for each medicinal herb, to the control group that received a diet supplemented with metal salts only. Great influence on all metal accumulation factors was observed in diet enriched with sage, which had significantly positive effect for all type of chicken meats. Conclusions Under the influence of medicinal herbs rich in different type of polyphenol, accumulation of metals in the liver, legs and breast chicken meat presents significant differences from the group that received a diet supplemented only with metal salts. Each medicinal herb from diet had a specific influence on the accumulation of metals and generally moderate or poor correlations were observed between total phenols and accumulation of metals. This may be due to antagonism between metal ions and presence of other chelating agents (amino acids and protein from feeding diets which can act as competitor for complexation of metals and influence

  13. Spectrophotometric analysis of vitamin E using Cu(I)-Bathocuproine or/and Fe(II)-2,4,6-tris-(2'-pyridyl)-s-triazine complexes

    International Nuclear Information System (INIS)

    Devi, I.; Memon, S. A.; Khuhawar, M.Y.

    2004-01-01

    Vitamin E (tocopherols and tocotrienols) antioxidants are determined by reducing Cu(II) to Cu(I) or Fe(III) to Fe(II) in presence of vitamin E and subsequent complexation of Cu(I) with bathocuproine and/or Fe(II) with 2,4,6-tris-(2'-pyridyl)-s-triazine (TPTZ). Both the reactions are monitored separately, Cu(I)-bathocuproine at 479 nm where as, Fe(II)-(TPTZ) at 595 nm spectrophotometrically. Linear calibration curves are achieved for both complexes between I to 5mu g ml-1 for vitamin E. The methods were applied for the determination of vitamin E in pharmaceutical preparations and edible oils. Vitamin E, from edible oils, was solvent extracted into n-hexane prior to saponification. Furthermore, a single lined flow was also examined. A larger excess of Cu(II) or Fe =(II) with different concentrations of vitamin E in buffer pH 4 was run on the line and constant amounts of reagent bathocuproine or TPTZ in each case was injected through the injector. The peak height shows a linear relationship for vitamin E between 0.5 to 2.5 mu g ml-1 for both complexes. (author)

  14. The improvement of the superconducting Y-Ba-Cu-O magnet characteristics through shape recovery strain of Fe-Mn-Si alloys

    International Nuclear Information System (INIS)

    Shimpo, Y.; Seki, H.; Wongsatanawarid, A.; Taniguchi, S.; Maruyama, T.; Kurita, T.; Murakami, M.

    2010-01-01

    Since bulk Y-Ba-Cu-O superconductors are brittle ceramics, reinforcement of mechanical properties is important for practical applications. It has been reported that bulk Y-Ba-Cu-O can be reinforced with Al or Fe based alloy ring, in that compression force acts on bulk Y-Ba-Cu-O due to a difference in thermal expansion coefficients. However, the shrinkage of the metal ring was not so large, and therefore careful adjustment of the circumference of the bulk and the metal rings was necessary. In this study, we employed Fe-Mn-Si shape memory alloy rings to reinforce bulk Y-Ba-Cu-O. The advantage of the shape memory alloy is that the shrinkage can take place on heating, and furthermore, the alloy shrinks and compresses the bulk body on cooling. Bulk Y-Ba-Cu-O superconductor 22.8 mm in diameter was inserted in a Fe-Mn-Si ring 23.0 mm in inner diameter at room temperature. Beforehand, the Fe-Mn-Si ring was expanded by 12% strain at room temperature. Then the composite was heated to 673 K. At room temperature, the Fe-Mn-Si ring firmly gripped the bulk superconductor. We then measured trapped fields before and after the ring reinforcement, and found that the trapped field was improved through the treatment.

  15. The combination of activated natural zeolite-bentonite to reduce Fe and Cu in refined bleached palm oil (RBPO) by using atomic absorption spectrophotometer method

    Science.gov (United States)

    Zakwan; Raja, PM; Giyanto

    2018-02-01

    Indonesia is one of the crude palm oil (CPO) production country in the world. As many products are derivated from the CPO, the quality must be increased continuously. One of the things that influence the quality of palm oil is the Fe and Cu content. The objective of this research was to reduce Fe and Cu content in Refined Bleached Palm Oil (RBPO). In processing CPO or Refined Bleachead Palm Oil (RBPO) may be contaminated by Fe and Cu from metal tank and pipe in the factory. The zeolite and bentonite was activated by maceration method using hydrochloric acid (0,1 N). Four batch reactions consisting of refined palm oil (RPO), activated natural zeolite-bentonite (ANZB) was bleached by heating and stirring them at about 105°C and 1200 rpm for 30 minutes. The results showed that all combinations of ANZB can reduce the Fe content. Thereafter, the optimal combination of ANZB was obtained in K1, K2 and K4 with Cu content 0.02 ppm. In the future, it is needed to study on the reduction of the Fe and Cu content in palm oil with the other adsorbent.

  16. Magnetic properties of CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles surrounded by amorphous SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Mori, K.; Hachisu, M.; Yamazaki, T.; Ichiyanagi, Y., E-mail: yuko@ynu.ac.jp [Department of Physics, Graduate School of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)

    2015-05-07

    CuFe{sub 1−x}Cr{sub x}O{sub 2} (0 ≤ x ≤ 1.0) nanoparticles surrounded by amorphous SiO{sub 2} with an average diameter of 30–50 nm were synthesized using a wet chemical method. The annealing temperatures were controlled to yield various sizes of single-phase CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles. CuFeO{sub 2} bulk crystal is known to have a multiferroic delafossite structure with two Néel temperatures of 11 and 14 K; however, the transition temperature shifted higher as the Cr–ion doping level increased. In addition, the lattice constants decreased in accordance with increased Cr-ion doping, which was confirmed by X-ray diffraction measurements. The magnetization curves showed weak ferromagnetic behavior and no coercivity was observed. Hence, frustration in the triangular lattice of the delafossite structure can be released by Cr–ion doping and higher magnetization can be expected. A fine structure analysis through X-ray absorption fine structure measurements was also conducted. It was found that the structure of the Cu ion is similar to that of Cu{sub 2}O, and the c axis of the CuFe{sub 1−x}Cr{sub x}O{sub 2} should be shortened by the Cr–ion doping.

  17. Pile oscillator measurements of thermal absorption cross sections of Al, Mg, Fe and Cu; Mesure des sections efficaces thermiques d'absorption de l'Al, du Mg, du Fe et du Cu par la methode d'oscillation

    Energy Technology Data Exchange (ETDEWEB)

    Carre, J C; Vidal, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The phase oscillation technique used at ZOE has the property of reducing of a marked factor the effect of neutron scattering by the sample. The absorption cross sections of poorly absorbing and highly scattering materials have been measured; for neutrons of 2,200 m/s, the following values are obtained: 229 {+-} 3 mb for Al; 64.2 {+-} 1.5 mb for Mg, 2.53 {+-} 0.03 b for Fe and 3.74 {+-} 0.04 b for Cu. (authors) [French] La methode d'oscillation de phase utilisee a ZOE possede la propriete de diminuer d'un facteur important l'influence de la diffusion. Les sections efficaces de capture de materiaux peu capturants et tres diffusants, ont ete mesurees; pour des neutrons de 2200 m/s, on obtient pour l'Al: 229 {+-} 3mb, pour le Mg: 64,2 {+-} 1,5 mb, pour le Fe: 2,53 {+-} 0,03 b et pour le Cu: 3,74 {+-} 0,04 b. (auteurs)

  18. Mixed-Spin Diamond Chain Cu2FePO4F4(H2O)4 with a Noncollinear Spin Order and Possible Successive Phase Transitions.

    Science.gov (United States)

    Lu, Hongcheng; Hayashi, Naoaki; Matsumoto, Yuki; Takatsu, Hiroshi; Kageyama, Hiroshi

    2017-08-07

    A diamond spin chain system, one of the one-dimensional frustrated lattices, is known to exhibit novel properties, but experimental studies have been exclusively confined to materials with a single spin component. Here, we report on the synthesis, structure, and magnetic properties of a new diamond chain compound Cu 2 FePO 4 F 4 (H 2 O) 4 1 composed of mixed-spins of Cu 2+ (S = 1/2 × 2) and Fe 3+ (S = 5/2). Compound 1 crystallizes in the space group C2/c of the monoclinic crystal system with a = 7.7546(4) Å, b = 12.1290(6) Å, c = 9.9209(6) Å, β = 105.29(1)°, and Z = 4. DC magnetization, Mössbauer spectroscopy, and heat capacity measurements revealed an antiferromagnetic order at 11.3 K with a small ferromagnetic component. It is suggested that ferrimagnetic diamond chains are arranged in an antiferromagnetic fashion (i.e., [...Fe(↑)-2Cu(↓↓)-Fe(↑)...] and [...Fe(↓)-2Cu(↑↑)-Fe(↓)...]) within the ab plane to cancel net magnetization, and the spin orientation of the diamond chains changes alternately along the c axis due to the magnetic anisotropy, leading to a noncollinear spin order. Furthermore, another anomaly is observed in the heat capacity at around 3 K, suggesting a successive magnetic transition or crossover due to competing magnetic interactions.

  19. Production of 68Ge, 64Cu, 86Y, 89Zr, 73Se, 77Br and 124I positron emitting radionuclides through future laser-accelerated proton beams at ELI-Beamlines for innovative PET diagnostics

    OpenAIRE

    Italiano, Antonio; Amato, Ernesto; Minutoli, Fabio; Margarone, Daniele; Baldari, Sergio

    2016-01-01

    The development of innovative production pathways for high-Z positron emitters is of great interest to enlarge the applicability of PET diagnostics, especially in view of the continuous development of new radiopharmaceuticals. We evaluated the theoretical yields of 64Cu, 86Y, 89Zr, 73Se, 77Br and 124I PET isotopes, plus the 68Ge isotope, parent of the 68Ga positron emitter, in the hypothesis of production through laser-accelerated proton sources expected at the ELI-Beamlines facility. By mean...

  20. Synthesis and the crystal and molecular structures of (H3L . Cl)[CoCl4] and H2L[CuBr4] (L is 2,4,6-Tri(N,N-dimethylamino)methylphenol)

    International Nuclear Information System (INIS)

    Kovalchukova, O. V.; Stash, A. I.; Strashnova, S. B.; Romashkina, E. P.; Zaitsev, B. E.

    2010-01-01

    The complex compounds (H 3 L . Cl)[CoCl 4 ] (I) and H 2 L[CuBr 4 ] (II), where L is 2,4,6-tri(N,N-dimethylamino)methylphenol, were isolated in the crystalline state and studied by X-ray diffraction. The organic cations were found to be outer-sphere ligands. All three nitrogen atoms of the tertiary amino groups are protonated. In compound I, the H 3 L 3+ cation exists as the cis tautomer. In compound II, the H 2 L 2+ dication exists as the trans isomer. In the crystal structure, the dications are arranged in layers via hydrogen bonds.