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Sample records for fe-doped calcium sulfide

  1. Magnetic properties study on Fe-doped calcium phosphate

    NASA Astrophysics Data System (ADS)

    Silva, C. C.; Vasconcelos, I. F.; Sombra, A. S. B.; Valente, M. A.

    2009-11-01

    Calcium phosphates are very important for applications in medicine due to their properties such as biocompatibility and bioactivity. In order to enhance these properties, substitution of calcium with other ions has been proposed. Partial substitution of calcium by different ions has been made in order to improve the properties of the calcium phosphates and also to allow new applications of apatite in medicine. In this work, hydroxyapatite [Ca10(PO4)6(OH)2—HAP] was prepared by high-energy dry milling (20 h) and mixed with iron oxide (5 wt.%). The mixture was calcinated at 900 °C for 5 h with a heating rate of 3 °C min-1 in an attempt to introduce iron oxide into the HAP structure. The sintered sample was characterized using x-ray diffraction (XRD) and magnetization. The 57Fe-Mössbauer spectra of the calcium phosphate oxides were also measured, revealing the presence of iron in three different phases: Ca2Fe2O5, Fe2O3 and hydroxyapatite.

  2. Effect of Si and Fe doping on calcium phosphate glass fibre reinforced polycaprolactone bone analogous composites.

    PubMed

    Mohammadi, M Shah; Ahmed, I; Muja, N; Almeida, S; Rudd, C D; Bureau, M N; Nazhat, S N

    2012-04-01

    Reinforcing biodegradable polymers with phosphate-based glass fibres (PGF) is of interest for bone repair and regeneration. In addition to increasing the mechanical properties, PGF can also release bioinorganics, as they are water soluble, a property that may be controllably translated into a fully degradable composite. Herein, the effect of Si and Fe on the solubility of calcium-containing phosphate-based glasses (PG) in the system (50P(2)O(5)-40CaO-(10-x)SiO(2)-xFe(2)O(3), where x=0, 5 and 10 mol.%) were investigated. On replacing SiO(2) with Fe(2)O(3), there was an increase in the glass transition temperature and density of the PG, suggesting greater crosslinking of the phosphate chains. This significantly reduced the dissolution rates of degradation and ion release. Two PG formulations, 50P(2)O(5)-40CaO-10Fe(2)O(3) (Fe10) and 50P(2)O(5)-40CaO-5Fe(2)O(3)-5SiO(2) (Fe5Si5), were melt drawn into fibres and randomly incorporated into polycaprolactone (PCL). Initially, the flexural strength and modulus significantly increased with PGF incorporation. In deionized water, PCL-Fe(5)Si(5) displayed a significantly greater weight loss and ion release compared with PCL-Fe10. In simulated body fluid, brushite was formed only on the surface of PCL-Fe(5)Si(5). Dynamic mechanical analysis in phosphate buffered saline (PBS) at 37°C revealed that the PCL-Fe10 storage modulus (E') was unchanged up to day 7, whereas the onset of PCL-Fe(5)Si(5)E' decrease occurred at day 4. At longer-term ageing in PBS, PCL-Fe(5)Si(5) flexural strength and modulus decreased significantly. MC3T3-E1 preosteoblasts seeded onto PCL-PGF grew up to day 7 in culture. PGF can be used to control the properties of biodegradable composites for potential application as bone fracture fixation devices. PMID:22248526

  3. Hydrogen sulfide promotes calcium uptake in larval zebrafish.

    PubMed

    Kwong, Raymond W M; Perry, Steve F

    2015-07-01

    Hydrogen sulfide (H2S) can act as a signaling molecule for various ion channels and/or transporters; however, little is known about its potential involvement in Ca(2+) balance. Using developing zebrafish (Danio rerio) as an in vivo model system, the present study demonstrated that acute exposure to H2S donors increased Ca(2+) influx at 4 days postfertilization, while chronic (3-day) exposure caused a rise in whole body Ca(2+) levels. The mRNA expression of Ca(2+)-transport-related genes was unaffected by H2S exposure, suggesting that posttranscriptional modifications were responsible for the altered rates of Ca(2+) uptake. Indeed, treatment of fish with the protein kinase A inhibitor H-89 abolished the H2S-mediated stimulation of Ca(2+) influx, suggesting that H2S increased Ca(2+) influx by activating cAMP-protein kinase A pathways. Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are two key enzymes in the endogenous synthesis of H2S. Using an antisense morpholino knockdown approach, we demonstrated that Ca(2+) influx was reduced in CBS isoform b (CBSb)- but not in CSE-deficient fish. Interestingly, the reduction in Ca(2+) influx in CBSb-deficient fish was observed only in fish that were acclimated to low-Ca(2+) water (i.e., 25 μM Ca(2+); control: 250 μM Ca(2+)). Similarly, mRNA expression of cbsb but not cse was increased in fish acclimated to low-Ca(2+) water. Results from whole-mount immunohistochemistry further revealed that CBSb was expressed in Na(+)-K(+)-ATPase-rich cells, which are implicated in Ca(2+) uptake in zebrafish larvae. Collectively, the present study suggests a novel role for H2S in promoting Ca(2+) influx, particularly in a low-Ca(2+) environment. PMID:25948733

  4. Studying inhibition of calcium oxalate stone formation: an in vitro approach for screening hydrogen sulfide and its metabolites

    PubMed Central

    Vaitheeswari, S.; Sriram, R.; Brindha, P.; Kurian, Gino A.

    2015-01-01

    ABSTRACT Purpose: Calcium oxalate urolithiasis is one of the most common urinary tract diseases and is of high prevalence. The present study proposes to evaluate the antilithiatic property of hydrogen sulfide and its metabolites like thiosulfate & sulfate in an in vitro model. Materials and Methods: The antilithiatic activity of sodium hydrogen sulfide (NaSH), sodium thiosulfate (Na2S2O3) and sodium sulfate (Na2SO4) on the kinetics of calcium oxalate crystal formation was investigated both in physiological buffer and in urine from normal and recurrent stone forming volunteers. The stones were characterized by optical and spectroscopic techniques. Results: The stones were characterized to be monoclinic, prismatic and bipyramidal habit which is of calcium monohydrate and dihydrate nature. The FTIR displayed fingerprint corresponding to calcium oxalate in the control while in NaSH treated, S=O vibrations were visible in the spectrum. The order of percentage inhibition was NaSH>Na2S2O3>Na2SO4. Conclusion: Our study indicates that sodium hydrogen sulfide and its metabolite thiosulfate are inhibitors of calcium oxalate stone agglomeration which makes them unstable both in physiological buffer and in urine. This effect is attributed to pH changes and complexing of calcium by S2O3 2-and SO4 2- moiety produced by the test compounds. PMID:26200543

  5. Investigating potential sources of Mercury's exospheric Calcium: Photon-stimulated desorption of Calcium Sulfide

    NASA Astrophysics Data System (ADS)

    Bennett, Chris J.; McLain, Jason L.; Sarantos, Menelaos; Gann, Reuben D.; DeSimone, Alice; Orlando, Thomas M.

    2016-02-01

    Ground-based and MErcury Surface, Space ENvironment, GEochemistry, and Ranging observations detected Ca0 and Ca+ in the exosphere of Mercury as well as unexpectedly high levels of sulfur on Mercury's surface. The mineral oldhamite ((Mg,Ca)S) could be a predominant component of the Mercury surface, particularly within the hollows identified within craters, and could therefore serve as a source of the observed exospheric calcium. Laboratory measurements on the photon-stimulated desorption (PSD) of CaS powder (an analog for oldhamite) at a wavelength of λ = 355 nm have been conducted, utilizing resonance-enhanced multiphoton ionization time-of-flight mass spectrometry to determine the yields and velocity distributions of Ca0. The desorbing Ca0 could be fit using two Maxwell-Boltzmann components: a 600 (±30) K thermal component and a 1389 (±121) K nonthermal component, the latter accounting for ~25% of the observed signal. Cross sections for PSD using 3.4 eV photons were found to be 1.1 (±0.7) × 10-20 cm2 for Ca0 and 3.2 (±0.9) × 10-24 cm2 for Ca+. Adopting these cross sections, a Monte Carlo model of the release of Ca0 by PSD from the Tyagaraja crater finds the neutral microexosphere created from this process to be substantial even if only 1% CaS is assumed in the hollows. Diffuse reflectance UV-visible measurements were made on the CaS powder to determine a bandgap, Eg, of 2.81 (±0.14) eV via the Tauc method.

  6. Involvement of Potassium Channels and Calcium-Independent Mechanisms in Hydrogen Sulfide-Induced Relaxation of Rat Mesenteric Small Arteries.

    PubMed

    Hedegaard, Elise R; Gouliaev, Anja; Winther, Anna K; Arcanjo, Daniel D R; Aalling, Mathilde; Renaltan, Nirthika S; Wood, Mark E; Whiteman, Matthew; Skovgaard, Nini; Simonsen, Ulf

    2016-01-01

    Endogenous hydrogen sulfide (H2S) is involved in the regulation of vascular tone. We hypothesized that the lowering of calcium and opening of potassium (K) channels as well as calcium-independent mechanisms are involved in H2S-induced relaxation in rat mesenteric small arteries. Amperometric recordings revealed that free [H2S] after addition to closed tubes of sodium hydrosulfide (NaHS), Na2S, and GYY4137 [P-(4-methoxyphenyl)-P-4-morpholinyl-phosphinodithioic acid] were, respectively, 14%, 17%, and 1% of added amount. The compounds caused equipotent relaxations in isometric myographs, but based on the measured free [H2S], GYY4137 caused more relaxation in relation to released free H2S than NaHS and Na2S in rat mesenteric small arteries. Simultaneous measurements of [H2S] and tension showed that 15 µM of free H2S caused 61% relaxation in superior mesenteric arteries. Simultaneous measurements of smooth muscle calcium and tension revealed that NaHS lowered calcium and caused relaxation of NE-contracted arteries, while high extracellular potassium reduced NaHS relaxation without corresponding calcium changes. In NE-contracted arteries, NaHS (1 mM) lowered the phosphorylation of myosin light chain, while phosphorylation of myosin phosphatase target subunit 1 remained unchanged. Protein kinase A and G, inhibitors of guanylate cyclase, failed to reduce NaHS relaxation, whereas blockers of voltage-gated KV7 channels inhibited NaHS relaxation, and blockers of mitochondrial complex I and III abolished NaHS relaxation. Our findings suggest that low micromolar concentrations of free H2S open K channels followed by lowering of smooth muscle calcium, and by another mechanism involving mitochondrial complex I and III leads to uncoupling of force, and hence vasodilation. PMID:26493746

  7. Fe-doped InN layers grown by molecular beam epitaxy

    SciTech Connect

    Wang Xinqiang; Liu Shitao; Ma Dingyu; Zheng Xiantong; Chen Guang; Xu Fujun; Tang Ning; Shen Bo; Zhang Peng; Cao Xingzhong; Wang Baoyi; Huang Sen; Chen, Kevin J.; Zhou Shengqiang; Yoshikawa, Akihiko

    2012-10-22

    Iron(Fe)-doped InN (InN:Fe) layers have been grown by molecular beam epitaxy. It is found that Fe-doping leads to drastic increase of residual electron concentration, which is different from the semi-insulating property of Fe-doped GaN. However, this heavy n-type doping cannot be fully explained by doped Fe-concentration ([Fe]). Further analysis shows that more unintentionally doped impurities such as hydrogen and oxygen are incorporated with increasing [Fe] and the surface is degraded with high density pits, which probably are the main reasons for electron generation and mobility reduction. Photoluminescence of InN is gradually quenched by Fe-doping. This work shows that Fe-doping is one of good choices to control electron density in InN.

  8. Hydrogen sulfide-induced itch requires activation of Cav3.2 T-type calcium channel in mice

    PubMed Central

    Wang, Xue-Long; Tian, Bin; Huang, Ya; Peng, Xiao-Yan; Chen, Li-Hua; Li, Jun-Cheng; Liu, Tong

    2015-01-01

    The contributions of gasotransmitters to itch sensation are largely unknown. In this study, we aimed to investigate the roles of hydrogen sulfide (H2S), a ubiquitous gasotransmitter, in itch signaling. We found that intradermal injection of H2S donors NaHS or Na2S, but not GYY4137 (a slow-releasing H2S donor), dose-dependently induced scratching behavior in a μ-opioid receptor-dependent and histamine-independent manner in mice. Interestingly, NaHS induced itch via unique mechanisms that involved capsaicin-insensitive A-fibers, but not TRPV1-expressing C-fibers that are traditionally considered for mediating itch, revealed by depletion of TRPV1-expressing C-fibers by systemic resiniferatoxin treatment. Moreover, local application of capsaizapine (TRPV1 blocker) or HC-030031 (TRPA1 blocker) had no effects on NaHS-evoked scratching. Strikingly, pharmacological blockade and silencing of Cav3.2 T-type calcium channel by mibefradil, ascorbic acid, zinc chloride or Cav3.2 siRNA dramatically decreased NaHS-evoked scratching. NaHS induced robust alloknesis (touch-evoked itch), which was inhibited by T-type calcium channels blocker mibefradil. Compound 48/80-induced itch was enhanced by an endogenous precursor of H2S (L-cysteine) but attenuated by inhibitors of H2S-producing enzymes cystathionine γ-lyase and cystathionine β-synthase. These results indicated that H2S, as a novel nonhistaminergic itch mediator, may activates Cav3.2 T-type calcium channel, probably located at A-fibers, to induce scratching and alloknesis in mice. PMID:26602811

  9. Hydrogen sulfide-induced itch requires activation of Cav3.2 T-type calcium channel in mice.

    PubMed

    Wang, Xue-Long; Tian, Bin; Huang, Ya; Peng, Xiao-Yan; Chen, Li-Hua; Li, Jun-Cheng; Liu, Tong

    2015-01-01

    The contributions of gasotransmitters to itch sensation are largely unknown. In this study, we aimed to investigate the roles of hydrogen sulfide (H2S), a ubiquitous gasotransmitter, in itch signaling. We found that intradermal injection of H2S donors NaHS or Na2S, but not GYY4137 (a slow-releasing H2S donor), dose-dependently induced scratching behavior in a μ-opioid receptor-dependent and histamine-independent manner in mice. Interestingly, NaHS induced itch via unique mechanisms that involved capsaicin-insensitive A-fibers, but not TRPV1-expressing C-fibers that are traditionally considered for mediating itch, revealed by depletion of TRPV1-expressing C-fibers by systemic resiniferatoxin treatment. Moreover, local application of capsaizapine (TRPV1 blocker) or HC-030031 (TRPA1 blocker) had no effects on NaHS-evoked scratching. Strikingly, pharmacological blockade and silencing of Cav3.2 T-type calcium channel by mibefradil, ascorbic acid, zinc chloride or Cav3.2 siRNA dramatically decreased NaHS-evoked scratching. NaHS induced robust alloknesis (touch-evoked itch), which was inhibited by T-type calcium channels blocker mibefradil. Compound 48/80-induced itch was enhanced by an endogenous precursor of H2S (L-cysteine) but attenuated by inhibitors of H2S-producing enzymes cystathionine γ-lyase and cystathionine β-synthase. These results indicated that H2S, as a novel nonhistaminergic itch mediator, may activates Cav3.2 T-type calcium channel, probably located at A-fibers, to induce scratching and alloknesis in mice. PMID:26602811

  10. Enhanced electromagnetic wave shielding effectiveness of Fe doped carbon nanotubes/epoxy composites

    NASA Astrophysics Data System (ADS)

    Wang, Zhou; Ejembi, John; Nwigboji, Ifeanyi; Zhao, Guang-Lin; Southern University A&M College Team

    2014-03-01

    Fe doped multi-walled carbon nanotubes (MWCNTs)/epoxy composites were fabricated for the investigation of electromagnetic interference (EMI) shielding. Compared with the pristine MWCNTs, a small amount of Fe doping into the MWCNTs can substantially improve the EMI shielding effectiveness (SE) of MWCNTs/epoxy composites. The highest EMI shielding effectiveness of the composites is -32 to -41 dB in the measured frequency range from 26 to 40 GHz for the sample with 8 wt.% Fe doped MWCNT loading. The contribution of EMI SE of the composites is mainly due to dielectric loss rather than magnetic loss. This work is funded by Air Force and NSF.

  11. Enhanced electromagnetic wave shielding effectiveness of Fe doped carbon nanotubes/epoxy composites

    NASA Astrophysics Data System (ADS)

    Wang, Zhou; Wei, Guodong; Zhao, Guang-Lin

    2013-10-01

    Fe doped multi-walled carbon nanotubes (MWCNTs)/epoxy composites were fabricated for the investigation of electromagnetic interference (EMI) shielding. Compared with the pristine MWCNTs, a small amount of Fe doping into the MWCNTs can substantially improve the EMI shielding effectiveness (SE) of MWCNTs/epoxy composites. The highest EMI shielding effectiveness of the composites is -32 to -41 dB in the measured frequency range from 26 to 40 GHz for the sample with 8 wt. % Fe doped MWCNT loading. The contribution of EMI SE of the composites is mainly due to dielectric loss rather than magnetic loss.

  12. Room temperature ferromagnetism in undoped and Fe doped ZnO nanorods: Microwave-assisted synthesis

    SciTech Connect

    Limaye, Mukta V.; Singh, Shashi B.; Das, Raja; Poddar, Pankaj; Kulkarni, Sulabha K.

    2011-02-15

    One-dimensional (1D) undoped and Fe doped ZnO nanorods of average length {approx}1 {mu}m and diameter {approx}50 nm have been obtained using a microwave-assisted synthesis. The magnetization (M) and coercivity (H{sub c}) value obtained for undoped ZnO nanorods at room temperature is {approx}5x10{sup -3} emu/g and {approx}150 Oe, respectively. The Fe doped ZnO samples show significant changes in M -H loop with increasing doping concentration. Both undoped and Fe doped ZnO nanorods exhibit a Curie transition temperature (T{sub c}) above 390 K. Electron spin resonance and Moessbauer spectra indicate the presence of ferric ions. The origin of ferromagnetism in undoped ZnO nanorods is attributed to localized electron spin moments resulting from surface defects/vacancies, where as in Fe doped samples is explained by F center exchange mechanism. -- Graphical abstract: Room temperature ferromagnetism has been reported in undoped and Fe doped ZnO nanorods of average length {approx}1 {mu}m and diameter {approx}50 nm. Display Omitted Research Highlights: {yields} Microwave-assisted synthesis of undoped and Fe doped ZnO nanorods. {yields} Observation of room temperature ferromagnetism in undoped and Fe doped ZnO nanorods. {yields} Transition temperature (T{sub c}) obtained in undoped and doped samples is above 390 K. {yields} In undoped ZnO origin of ferromagnetism is explained in terms of defects/vacancies. {yields} Ferromagnetism in Fe doped ZnO is explained by F-center exchange mechanism.

  13. Preparation, characterization and electronic structures of Fe-doped TiO{sub 2} nanostructured fibers

    SciTech Connect

    Zhu, L.Y.; Liu, X.T.; Qin, W.W.; Liu, X.S.; Cai, N.N.; Wang, X.Q.; Lin, X.J.; Zhang, G.H.; Xu, D.

    2013-07-15

    Graphical abstract: - Highlights: • Mesoporous Fe-doped TiO{sub 2} fibers were prepared on a large scale by sol–gel method. • Fe-doping greatly enhance the visible-light photocatalytic activity of TiO{sub 2} fibers. • First-principle study the effects of different replaced sites on the absorption edge and band gap. - Abstract: Mesoporous and nanostructured Fe-doped TiO{sub 2} fibers were fabricated on a large scale by sol–gel method combined with the polyorganotitanium as the precursor and ferric nitrate as dopant. The prepared fibers were characterized by XRD, XPS, SEM, TEM, N{sub 2} adsorption–desorption isotherms and UV–vis spectroscopy. The photocatalytic activity was evaluated by photodegradation of methyl orange (MO) aqueous solution under UV and visible-light irradiation. Compared with different types of photocatalysts, the 0.5%Fe-doped TiO{sub 2} fibers exhibit super photocatalytic activity. This is ascribed to the fact that the Fe-doping induces the shift of the absorption edge into the visible-light range with the narrowing of the band gap and reduces the recombination of the photo-generated electrons and holes. Furthermore, first-principle study for their electronic structures was carried out to confirm the effects of different replaced lattice sites on the red shift of the absorption edge and the changes of the band gap of the Fe-doped TiO{sub 2} fibers.

  14. Importance of doping and frustration in itinerant Fe-doped Cr2Al

    DOE PAGESBeta

    Susner, M. A.; Parker, D. S.; Sefat, A. S.

    2015-05-12

    We performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x≈0.125 after which point increasing paramagnetic behavior is exhibited. Moreover, this is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculations explainmore » that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.« less

  15. Fe doped TiO2-graphene nanostructures: synthesis, DFT modeling and photocatalysis.

    PubMed

    Farhangi, Nasrin; Ayissi, Serge; Charpentier, Paul A

    2014-08-01

    In this work, Fe-doped TiO(2) nanoparticles ranging from a 0.2 to 1 weight % were grown from the surface of graphene sheet templates containing -COOH functionalities using sol-gel chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a variety of analytical techniques, with the coordination mechanism examined theoretically using the density functional theory (DFT). Scanning electron microscopy and transmission electron microscopy images showed excellent decoration of the Fe-doped TiO(2) nanoparticles on the surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to non-graphene and pure TiO(2) analogs, showing a plateau at 0.6% Fe. Interactions between graphene and Fe-doped anatase TiO(2) were also studied theoretically using the Vienna ab initio Simulation Package based on DFT. Our first-principles theoretical investigations validated the experimental findings, showing the strength in the physical and chemical adsorption between the graphene and Fe-doped TiO(2). The resulting assemblies were tested for photodegradation under visible light using 17β-estradiol (E2) as a model compound, with all investigated catalysts showing significant enhancements in photocatalytic activity in the degradation of E2. PMID:25002220

  16. TDPAC measurements in pure and Fe-doped In 2 O 3

    NASA Astrophysics Data System (ADS)

    Sena, C.; Costa, M. S.; Cabrera-Pasca, G. A.; Saxena, R. N.; Carbonari, A. W.

    2013-05-01

    Measurements of the electric quadrupole interactions were used to characterize pure and Fe-doped In2O3 samples using perturbed γ- γ angular correlation (PAC) technique with 111In-111Cd radioactive probe. The samples of pure as well as 1 % and 5 % Fe-doped In2O3 were prepared by sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). The PAC measurements were carried out with a conventional fast-slow coincidence set-up using four BaF2 detectors as a function of temperature from 295 K to 1073 K. The powder XRD spectra analyzed with Rietveld method as well as SEM and EDS results showed that Fe-doped samples are homogeneous without any secondary iron oxide phases. The PAC spectra of pure and 1 % Fe-doped In2O3 show well-known characteristic quadrupole frequencies for the two non-equivalent sites in the bixbyte structure. The hyperfine parameters in these cases change little with temperature. For the 5 % Fe-doped sample however the PAC spectra changed significantly and a third frequency with large η appears.

  17. Structural, magnetic, and transport properties of Fe-doped CoTiSb epitaxial thin films

    SciTech Connect

    Sun, N. Y.; Zhang, Y. Q.; Che, W. R.; Shan, R.; Qin, J.

    2015-11-07

    Epitaxial intrinsic and Fe-doped CoTiSb thin films with C1{sub b} structure were grown on MgO(100) substrates by magnetron sputtering. The semiconducting-like behavior in both intrinsic and Fe-doped thin films was demonstrated by temperature dependence of longitudinal resistivity. The Fe-doped CoTiSb films with a wide range of doping concentrations can maintain semiconducting-like and magnetic properties simultaneously, while the semiconducting behavior is weakening with the increasing Fe concentration. For 21 at. % Fe-doped film, low lattice magnetic moment (around 0.65 μ{sub B}) and high resistivity (larger than 800 μΩ cm) are beneficial to its application as a magnetic electrode in spintronic devices. Anomalous Hall effect of 21 at. % Fe-doped film was also investigated and its behaviors can be treated well by recent-reported anomalous Hall scaling including the contribution of spin-phonon skew scattering.

  18. Fe doped TiO2-graphene nanostructures: synthesis, DFT modeling and photocatalysis

    NASA Astrophysics Data System (ADS)

    Farhangi, Nasrin; Ayissi, Serge; Charpentier, Paul A.

    2014-08-01

    In this work, Fe-doped TiO2 nanoparticles ranging from a 0.2 to 1 weight % were grown from the surface of graphene sheet templates containing -COOH functionalities using sol-gel chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a variety of analytical techniques, with the coordination mechanism examined theoretically using the density functional theory (DFT). Scanning electron microscopy and transmission electron microscopy images showed excellent decoration of the Fe-doped TiO2 nanoparticles on the surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to non-graphene and pure TiO2 analogs, showing a plateau at 0.6% Fe. Interactions between graphene and Fe-doped anatase TiO2 were also studied theoretically using the Vienna ab initio Simulation Package based on DFT. Our first-principles theoretical investigations validated the experimental findings, showing the strength in the physical and chemical adsorption between the graphene and Fe-doped TiO2. The resulting assemblies were tested for photodegradation under visible light using 17β-estradiol (E2) as a model compound, with all investigated catalysts showing significant enhancements in photocatalytic activity in the degradation of E2.

  19. Superparamagnetic behavior of Fe-doped SnO{sub 2} nanoparticles

    SciTech Connect

    Hachisu, M.; Onuma, K.; Kondo, T.; Miike, K.; Miyasaka, T.; Mori, K.; Ichiyanagi, Y.

    2014-02-20

    SnO{sub 2} is an n-type semiconductor with a wide band gap of 3.62 eV, and SnO{sub 2} nanoparticles doped with magnetic ions are expected to realized new diluted magnetic semiconductors (DMSs). Realizing ferromagnetism at room temperature is important for spintronics device applications, and it is interesting that the magnetic properties of these DMS systems can be varied significantly by modifying the preparation methods or conditions. In this study, the magnetic properties of Fe-doped (3% and 5%) SnO{sub 2} nanoparticles, prepared using our novel chemical preparation method and encapsulated in amorphous SiO{sub 2}, were investigated. The particle size (1.8–16.9 nm) and crystal phase were controlled by the annealing temperature. X-ray diffraction confirmed a rutile SnO{sub 2} single-phase structure for samples annealed at 1073–1373 K, and the composition was confirmed using X-ray fluorescence analysis. SQUID magnetometer measurements revealed superparamagnetic behavior of the 5%-Fe-doped sample at room temperature, although SnO{sub 2} is known to be diamagnetic. Magnetization curves at 5 K indicated that the 3%-Fe-doped has a larger magnetization than that of the 5%-Fe-doped sample. We conclude that the magnetization of the 5%-Fe-doped sample decreased at 5 K due to the superexchange interaction between the antiferromagnetic coupling in the nanoparticle system.

  20. Influence of Fe doping on the structural, optical and acetone sensing properties of sprayed ZnO thin films

    SciTech Connect

    Prajapati, C.S.; Kushwaha, Ajay; Sahay, P.P.

    2013-07-15

    Graphical abstract: All the films are found to be polycrystalline ZnO possessing hexagonal wurtzite structure. The intensities of all the peaks are diminished strongly in the Fe-doped films, indicating their lower crystallinity as compared to the undoped ZnO film. The average crystallite size decreases from 35.21 nm (undoped sample) to 15.43 nm (1 at% Fe-doped sample). - Highlights: • Fe-doped ZnO films show smaller crystallinity with crystallite size: 15–26 nm. • Optical band gap in ZnO films decreases on Fe doping. • Fe-doped films exhibit the normal dispersion for the wavelength range 450–600 nm. • PL spectra of the Fe-doped films show quenching of the broad green-orange emission. • Acetone response of the Fe-doped films increases considerably at 300 °C. - Abstract: The ZnO thin films (undoped and Fe-doped) deposited by chemical spray pyrolysis technique have been analyzed by X-ray powder diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results show that all the films possess hexagonal wurtzite structure of zinc oxide having crystallite sizes in the range 15–36 nm. On 1 at% Fe doping, the surface roughness of the film increases which favors the adsorption of atmospheric oxygen on the film surface and thereby increase in the gas response. Optical studies reveal that the band gap decreases due to creation of some defect energy states below the conduction band edge, arising out of the lattice disorder in the doped films. The refractive index of the films decreases on Fe doping and follows the Cauchy relation of normal dispersion. Among all the films examined, the 1 at% Fe-doped film exhibits the maximum response (∼72%) at 300 °C for 100 ppm concentration of acetone in air.

  1. Fe doped ZnO thin film for mediator-less biosensing application

    NASA Astrophysics Data System (ADS)

    Saha, Shibu; Tomar, Monika; Gupta, Vinay

    2012-05-01

    Fe doped ZnO (FZO) thin film is prepared by pulsed laser deposition for its application as mediator-less biosensing matrix. Fe doping introduces redox centre in ZnO along with shallow donor level and promotes the electron transfer capability due to substitution of Fe at Zn sites. Glucose oxidase (GOx), chosen as model enzyme, was immobilized on surface of the prepared matrix. Cyclic voltammetry and photometric assay show that the developed bio-electrode, GOx/FZO/indium tin oxide/Glass is sensitive to glucose concentration with enhanced response (0.2 µA mM-1 cm-2) and low Km (3.01 mM). The results show promising application of Fe doped ZnO thin film as an attractive matrix for mediator-less biosensing.

  2. Effect of Fe doping concentration on photocatalytic activity of ZnO nanosheets under natural sunlight

    SciTech Connect

    Khokhra, Richa; Kumar, Rajesh

    2015-05-15

    A facile room temperature, aqueous solution-based chemical method has been adopted for large-scale synthesis of Fe doped ZnO nanosheets. The XRD and SEM results reveal the as-synthesized products well crystalline and accumulated by large amount of interweave nanosheets, respectively. Energy dispersive spectroscopy data confirmed Fe doping of the ZnO nanosheets with a varying Fe concentration. The photoluminescence spectrum reveals a continuous suppression of defect related emissions intensity by increasing the concentration of the Fe ion. A photocatalytic activity using these samples under sunlight irradiation in the mineralization of methylene blue dye was investigated. The photocatalytic activity of Fe doped ZnO nanosheets depends upon the presence of surface oxygen vacancies.

  3. Hydrothermal synthesis of Fe-doped TiO2 nanostructure photocatalyst

    NASA Astrophysics Data System (ADS)

    Nghia Nguyen, Van; Khoa Truong Nguyen, Ngoc; Nguyen, Phi Hung

    2011-09-01

    Fe-doped TiO2 catalyst was prepared by the hydrothermal method. The resulting nanopowders were characterized by x-ray diffraction, transmission electron microscopy and Raman and UV-visible spectroscopies. The photocatalytic activity of the Fe-doped TiO2 was tested by decomposition of methylene orange with a concentration of 10 mg l‑1 in aqueous solution. The obtained results showed that methylene orange was significantly degraded after irradiation for 90 min under a halogen lamp and sunlight. The doping effect on the photocatalytic activity of the iron-doped catalyst samples are discussed.

  4. Calcium

    MedlinePlus

    ... of calcium dietary supplements are carbonate and citrate. Calcium carbonate is inexpensive, but is absorbed best when taken ... antacid products, such as Tums® and Rolaids®, contain calcium carbonate. Each pill or chew provides 200–400 mg ...

  5. Improved gas sensing and dielectric properties of Fe doped hydroxyapatite thick films: Effect of molar concentrations

    SciTech Connect

    Mene, Ravindra U.; Mahabole, Megha P.; Mohite, K.C.; Khairnar, Rajendra S.

    2014-02-01

    Highlights: • We report improved gas sensing and dielectric characteristics of Fe ion exchanged HAp films. • Fe doped HAp film shows maximum gas response at relatively lower temperature. • Response and gas uptake capacity of sensors is improved for appropriate amount of Fe ions in HAp matrix. • Fe-HAp films exhibit remarkable improvement in dielectric properties compared to pure HAp. • Fe doped HAp films show significant improvement in gas sensing as well as in dielectric properties. - Abstract: In the present work Fe doped hydroxyapatite (Fe-HAp) thick films has been successfully utilized to improve the gas sensing as well as its dielectric properties. Initially, HAp nano powder is synthesized by chemical precipitation process and later on Fe ions are doped in HAp by ion exchange process. Structural and morphological modifications are observed by means of X-ray diffraction and scanning electron microscopy analysis. The sensing parameters such as operating temperature, response/recovery time and gas uptake capacity are experimentally determined. The Fe-HAp (0.05 M) film shows improved CO and CO{sub 2} gas sensing capacity at lower operating temperature compared to pure HAp. Moreover, variation of dielectric constant and dielectric loss for pure and Fe-HAp thick films are studied as a function of frequency in the range of 10 Hz–1 MHz. The study reveals that Fe doped HAp thick films improve the sensing and dielectric characteristics as compared to pure HAp.

  6. Ferromagnetic interactions and martensitic transformation in Fe doped Ni-Mn-In shape memory alloys

    SciTech Connect

    Lobo, D. N.; Priolkar, K. R.; Emura, S.; Nigam, A. K.

    2014-11-14

    The structure, magnetic, and martensitic properties of Fe doped Ni-Mn-In magnetic shape memory alloys have been studied by differential scanning calorimetry, magnetization, resistivity, X-ray diffraction (XRD), and EXAFS. While Ni{sub 2}MnIn{sub 1−x}Fe{sub x} (0 ≤ x ≤ 0.6) alloys are ferromagnetic and non martensitic, the martensitic transformation temperature in Ni{sub 2}Mn{sub 1.5}In{sub 1−y}Fe{sub y} and Ni{sub 2}Mn{sub 1.6}In{sub 1−y}Fe{sub y} increases for lower Fe concentrations (y ≤ 0.05) before decreasing sharply for higher Fe concentrations. XRD analysis reveals presence of cubic and tetragonal structural phases in Ni{sub 2}MnIn{sub 1−x}Fe{sub x} at room temperature with tetragonal phase content increasing with Fe doping. Even though the local structure around Mn and Ni in these Fe doped alloys is similar to martensitic Mn rich Ni-Mn-In alloys, presence of ferromagnetic interactions and structural disorder induced by Fe affect Mn-Ni-Mn antiferromagnetic interactions resulting in suppression of martensitic transformation in these Fe doped alloys.

  7. Calcium

    MedlinePlus

    ... body stores more than 99 percent of its calcium in the bones and teeth to help make and keep them ... in the foods you eat. Foods rich in calcium include Dairy products such as milk, cheese, and yogurt Leafy, green vegetables Fish with soft bones that you eat, such as canned sardines and ...

  8. Theoretical study of the adsorption of pentachlorophenol on the pristine and Fe-doped boron nitride nanotubes.

    PubMed

    Wang, Ruo-xi; Zhang, Dong-ju; Zhu, Rong-xiu; Liu, Cheng-bu

    2014-02-01

    To explore the novel application of boron nitride nanotubes (BNNTs), we investigated the interaction of pentachlorophenol (PCP) pollutant with the pristine and Fe doped (Fe-doped) (8, 0) single-walled BNNTs by performing density functional theory calculations. Compared with the weak physisorption on the pristine BNNT, PCP molecule presents strong chemisorption on the Fe-doped BNNT. The calculated data for the electronic properties indicate that doping Fe atom into the BNNT significantly improves the electronic transport property of BNNT, induces magnetism in the BNNT, and increases its adsorption sensitivity toward PCP molecule. It is suggested that doping BNNTs with Fe is an available strategy for improving the properties of BNNTs, and that Fe-doped BNNT would be a potential resource for adsorbing PCP pollutant in environments. PMID:24504454

  9. Inhibition of hydrogen sulfide on the proliferation of vascular smooth muscle cells involved in the modulation of calcium sensing receptor in high homocysteine.

    PubMed

    Wang, Yuwen; Wang, Xiyao; Liang, Xiaohui; Wu, Jichao; Dong, Shiyun; Li, Hongzhu; Jin, Meili; Sun, Dianjun; Zhang, Weihua; Zhong, Xin

    2016-09-10

    Hyperhomocysteinemia induces the proliferation of vascular smooth muscle cells (VSMCs). Hydrogen sulfide (H2S) inhibits the phenotype switch of VSMCs and calcium-sensing receptor (CaSR) regulated the production of endogenous H2S. However, whether CaSR inhibits the proliferation of VSMCs by regulating the endogenous cystathionine-gamma-lyase (CSE, a major enzyme that produces H2S) pathway in high homocysteine (HHcy) has not been previously investigated. The intracellular calcium concentration, the concentration of H2S, the cell viability, the proliferation and the expression of proteins of cultured VSMCs from rat thoracic aortas were measured, respectively. The results showed that the [Ca(2+)]i and the expression of p-CaMK and CSE increased upon treatment with CaSR agonist. In HHcy, the H2S concentration decrease, the proliferation and migration rate increased, the expression of Cyclin D1, PCNA, Osteopontin and p-Erk1/2 increased while the α-SM actin, P21(Cip/WAK-1) and Calponin decreased. The CaSR agonist or exogenous H2S significantly reversed the changes of VSMCs caused by HHcy. In conclusion, our results demonstrated that CaSR regulate the endogenous CSE/H2S is related to the PLC-IP3 receptor and CaM signal pathways which inhibit the proliferation of VSMCs, and the latter is involved in the Erk1/2 dependent signal pathway in high homocysteine. PMID:27502588

  10. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  11. Structural, optical and magnetic properties of Fe-doped barium stannate thin films grown by PLD

    NASA Astrophysics Data System (ADS)

    James, K. K.; Aravind, Arun; Jayaraj, M. K.

    2013-10-01

    Barium stannate is a wide band gap semiconductor with cubic perovskite structure. Polycrystalline bulk samples of BaSn1-xFexO3d (BFS), with x = 0.00, 0.02, 0.03, 0.05 and 0.10 were prepared by solid-state reaction. In this paper, we report the growth of undoped and Fe doped barium stannate thin films on fused silica substrate using pulsed laser deposition (PLD) technique at a relatively high substrate temperature and low oxygen pressure. The deposited films have wide bandgap and are transparent in the visible region. The X-ray diffraction analysis of the films confirmed the cubic structure. Microstructural studies were carried out using micro-Raman spectroscopy and AFM analysis. Defect induced Raman shifts were observed in the samples. Magnetic studies revealed an increase in magnetic properties for films doped with 10 at% Fe doped samples.

  12. Ferromagnetism and ferroelectricity in Fe doped BaTiO3

    NASA Astrophysics Data System (ADS)

    Deka, Bipul; Ravi, S.; Perumal, A.; Pamu, D.

    2014-09-01

    We report the investigation of crystal structure, magnetic and dielectric properties of BaTi1-xFexO3 samples for x=0.0-0.3. The parent compound is found to crystallize in tetragonal structure while Fe doped samples are found to crystallize in the mixture of tetragonal and hexagonal phases but they are free from any impurity phase. Room temperature ferromagnetism with the transition temperature (Tc) of 462 K was observed for x=0.3 sample. Fe doped samples exhibit ferroelectric transition with transition temperature (TcF) in the range of 390 K for x=0.0-312 K for x=0.2. The dielectric constant, ε‧ is found to decrease with the increase in doping concentrations.

  13. Synthesis of Fe Doped ZnO Nanowire Arrays that Detect Formaldehyde Gas.

    PubMed

    Jeon, Yoo Sang; Seo, Hyo Won; Kim, Su Hyo; Kim, Young Keun

    2016-05-01

    Owing to their chemical and thermal stability and doping effects on providing electrons to the conduction band, doped ZnO nanowires have generated interest for use in electronic devices. Here we report hydrothermally grown Fe-doped ZnO nanowires and their gas-sensing properties. The synthesized nanowires have a high crystallinity and are 60 nm in diameter and 1.7 μm in length. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are employed to understand the doping effects on the microstructures and gas sensing properties. When the Fe-doped ZnO nanowire arrays were evaluated for gas sensing, responses were recorded through changes in temperature and gas concentration. Gas sensors consisting of ZnO nanowires doped with 3-5 at.% Fe showed optimum formaldehyde (HCHO) sensing performance at each working temperature. PMID:27483827

  14. High-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga,Fe)Sb

    NASA Astrophysics Data System (ADS)

    Tu, Nguyen Thanh; Hai, Pham Nam; Anh, Le Duc; Tanaka, Masaaki

    2016-05-01

    We show high-temperature ferromagnetism in heavily Fe-doped ferromagnetic semiconductor (Ga1-x,Fex)Sb (x = 23% and 25%) thin films grown by low-temperature molecular beam epitaxy. Magnetic circular dichroism spectroscopy and anomalous Hall effect measurements indicate intrinsic ferromagnetism of these samples. The Curie temperature reaches 300 K and 340 K for x = 23% and 25%, respectively, which are the highest values reported so far in intrinsic III-V ferromagnetic semiconductors.

  15. Ferromagnetic behaviour of Fe-doped ZnO nanograined films

    PubMed Central

    Protasova, Svetlana G; Mazilkin, Andrei A; Tietze, Thomas; Goering, Eberhard; Schütz, Gisela; Straumal, Petr B; Baretzky, Brigitte

    2013-01-01

    Summary The influence of the grain boundary (GB) specific area s GB on the appearance of ferromagnetism in Fe-doped ZnO has been analysed. A review of numerous research contributions from the literature on the origin of the ferromagnetic behaviour of Fe-doped ZnO is given. An empirical correlation has been found that the value of the specific grain boundary area s GB is the main factor controlling such behaviour. The Fe-doped ZnO becomes ferromagnetic only if it contains enough GBs, i.e., if s GB is higher than a certain threshold value s th = 5 × 104 m2/m3. It corresponds to the effective grain size of about 40 μm assuming a full, dense material and equiaxial grains. Magnetic properties of ZnO dense nanograined thin films doped with iron (0 to 40 atom %) have been investigated. The films were deposited by using the wet chemistry “liquid ceramics” method. The samples demonstrate ferromagnetic behaviour with J s up to 0.10 emu/g (0.025 μB/f.u.ZnO) and coercivity H c ≈ 0.03 T. Saturation magnetisation depends nonmonotonically on the Fe concentration. The dependence on Fe content can be explained by the changes in the structure and contiguity of a ferromagnetic “grain boundary foam” responsible for the magnetic properties of pure and doped ZnO. PMID:23844341

  16. Enhanced magnetic moment in ultrathin Fe-doped CoFe2O4 films

    NASA Astrophysics Data System (ADS)

    Moyer, J. A.; Vaz, C. A. F.; Kumah, D. P.; Arena, D. A.; Henrich, V. E.

    2012-11-01

    The effect of film thickness on the magnetic properties of ultrathin Fe-doped cobalt ferrite (Co1-xFe2+xO4) grown on MgO (001) substrates is investigated by superconducting quantum interference device magnetometry and x-ray magnetic linear dichroism, while the distribution of the Co2+ cations between the octahedral and tetrahedral lattice sites is studied with x-ray absorption spectroscopy. For films thinner than 10 nm, there is a large enhancement of the magnetic moment; conversely, the remanent magnetization and coercive fields both decrease, while the magnetic spin axes of all the cations become less aligned with the [001] crystal direction. In particular, at 300 K the coercive fields of the thinnest films vanish. The spectroscopy data show that no changes occur in the cation distribution as a function of film thickness, ruling this out as the origin of the enhanced magnetic moment. However, the magnetic measurements all support the possibility that these ultrathin Fe-doped CoFe2O4 films are transitioning into a superparamagnetic state, as has been seen in ultrathin Fe3O4. A weakening of the magnetic interactions at the antiphase boundaries, leading to magnetically independent domains within the film, could explain the enhanced magnetic moment in ultrathin Fe-doped CoFe2O4 and the onset of superparamagnetism at room temperature.

  17. Preparation of Fe-doped TiO2 nanoparticles immobilized on polyamide fabric

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Zhu, Hong

    2012-10-01

    A thin layer of nano-scaled Fe-doped TiO2 particles prepared by hydrothermal method is immobilized on the surface of polyamide 6 (PA6) fiber using tetrabutyl titanate as the precursor, ferric trichloride as the doping agent and chitosan as the dispersant agent. The morphology, crystal structure, thermal behavior, composition and chemical structure of PA6 fabric before and after treatments are characterized by means of scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry and thermal gravimetric analysis techniques. The properties of diffuse reflectance spectrum, tensile, air permeability, whiteness, yellowness and photocatalytic activity are also analyzed. It is found that the anatase phase Fe-doped TiO2 nanoparticles with crystal size of 12 nm or so are synthesized, and simultaneously grafted onto the fiber surface during the processing. Compared with the TiO2-coated fabric, the thermal stability of the Fe-doped TiO2-coated fabric changes a little. The absorption ability to ultraviolet (UV) rays and visible light is greatly improved. The breaking force and breaking elongation increase to some extent because of the shrinkage of fabric. The air permeability decreases distinctly. The color of PA6 fabric changes from white to light brownish because of the introduction of ferric trichloride. The photocatalytic activity of methylene blue decolorization is enhanced under sunlight and UV irradiation.

  18. Adsorption of bovine serum albumin onto synthetic Fe-doped geomimetic chrysotile

    PubMed Central

    Adamiano, Alessio; Lesci, Isidoro Giorgio; Fabbri, Daniele; Roveri, Norberto

    2015-01-01

    Synthetic stoichiometric and Fe-doped geomimetic chrysotile nanocrystals represent a reference standard to investigate the health hazard associated with mineral asbestos fibres. Experimental evidence suggests that the generation of reactive oxygen species and other radicals, catalysed by iron ions at the fibre surface, plays an important role in asbestos-induced cytotoxicity and genotoxicity. In this study, structural modification of bovine serum albumin (BSA) adsorbed onto synthetic chrysotile doped with different amounts of Fe has been investigated by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and analytical pyrolysis coupled with gas chromatography–mass spectrometry. FT-IR data evidenced a marked increase in disordered structures like random coil and β-turn of BSA–nanocrystal adduct with 0.52 wt% of Fe doped. The TGA profile of the BSA revealed that its interaction with the synthetic chrysotile surface was strongly affected by the substitution of Fe into the chrysotile structure. The 2,5-diketopiperazine yields, formed upon thermal degradation of the polypeptide chain (pyrolysis–gas chromatography), changed when the BSA was adsorbed on the nanofibres. In general, results suggested that minute amount (less than 1 wt%) of Fe doping in chrysotile affected the protein–nanofibre interactions, supporting the role that this element may play in asbestos toxicity. The catalytic role of iron and the consequent unfolding of protein due to the structural surface modification of nanofibres were also evaluated. PMID:26018963

  19. Single-step preparation, characterization and photocatalytic mechanism of mesoporous Fe-doped sulfated titania

    NASA Astrophysics Data System (ADS)

    Yang, Ying; Zhong, Hui; Tian, Congxue; Jiang, Zhiqiang

    2011-07-01

    Mesoporous Fe-doped sulfated titania photocatalysts were prepared by one-step thermal hydrolysis of industrial titanyl sulfate and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption-desorption techniques. The effects of the m(Fe)/m(TiO2) on the structures of the titania photocatalysts were investigated. The photocatalytic activity of the mesoporous Fe-doped sulfated titania catalysts was evaluated using the photooxidation of methylene blue in aqueous solutions under UV light irradiation. The results indicated that Fe3+ substitutes Ti4+ in titania lattice, which induced the formation of oxygen vacancies. The oxygen vacancies are favorable to the dissociation adsorption H2O and formation of surface hydroxyl group. Fe3+ captures the photoinduced electrons or holes that are conductive to the efficient separation of the photogenerated carriers, but too many doping Fe3+ will promote recombination of the photogenerated carrier. Sulfur species in the form of sulfate are incorporated into the network of Tisbnd Osbnd Ti and coordinated to titania in bidentate model, resulting in the strong inductive effect, large specific surface area, and mesoporous structure. All these are beneficial to improve the photocatalytic activities of the mesoporous Fe-doped sulfated titania photocatalysts.

  20. Comparative study of (N, Fe) doped TiO2 photocatalysts

    NASA Astrophysics Data System (ADS)

    Larumbe, S.; Monge, M.; Gómez-Polo, C.

    2015-02-01

    The effect of N and Fe doping on the structural, optical, photocatalytic and magnetic properties of TiO2 nanoparticles is analyzed. Undoped, N and Fe doped TiO2 nanoparticles were synthesized by sol-gel method. Titanium tetraisopropoxide (TTIP) was used as the alkoxyde precursor and iron (III) nitrate and urea were the employed precursors to obtain Fe and N doped TiO2 nanoparticles, respectively. Differential Scanning Calorimetry (DSC) and Thermogravimetrical Analysis (TGA) enabled the analysis of the thermal decomposition process and the final calcination temperature. X-Ray Diffraction patterns of the calcined nanoparticles displayed a monophasic anatase structure in all the samples with mean crystallite diameter around 4-6 nm. The introduction of Fe or N induced a red-shift in the absorption spectra. Such a red-shift is characterized by a decrease in the band-gap energy and the occurrence of an absorption (Urbach) tail in the visible region. Finally, the photocatalytic efficiency was evaluated under UV and Visible light, obtaining an improvement of the kinetic constants in the nitrogen doped TiO2 nanoparticles with respect to undoped and Fe doped TiO2. The differences in the photocatalytic response under Fe and N doping are also analyzed in terms of the magnetic response of the analyzed photocatalysts.

  1. Effect of Fe doping on the electrochemical capacitor behavior of MnO2 nanocrystals

    NASA Astrophysics Data System (ADS)

    Poonguzhali, R.; Shanmugam, N.; Gobi, R.; Senthilkumar, A.; Viruthagiri, G.; Kannadasan, N.

    2015-10-01

    In this work, the influence of Fe doping on the capacitance behavior of MnO2 nanoparticles synthesized by chemical precipitation was investigated. During the doping process the concentration of Fe was increased from 0.025 M to 0.125 M in steps of 0.025 M. The products obtained were characterized by X-ray diffraction, Fourier infrared spectroscopy, scanning electron microscopy and N2 adsorption-desorption isotherms. To demonstrate the suitability of Fe-doped MnO2 for capacitor applications, cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance were recorded. Among the different levels of doping, the specific capacitance of 912 F/g was delivered by 0.075 M of Fe-doped MnO2 at a scan rate of 10 mV/s, which is almost more than fourfold that of the bare MnO2 electrode (210 F/g). Moreover, for the same concentration the charge, discharge studies revealed the highest specific capacitance of 1084 F/g at a current density of 10 A/g.

  2. Fe Doped CdTeS Magnetic Quantum Dots for Bioimaging†

    PubMed Central

    Saha, Ajoy K.; Sharma, Parvesh; Sohn, Han-Byul; Ghosh, Siddhartha; Das, Ritesh. K.; Hebard, Arthur F.; Zeng, Huadong; Baligand, Celine; Walter, Glenn A.

    2013-01-01

    A facile synthesis of 3-6 nm, water dispersible, near-infrared (NIR) emitting, quantum dots (QDs) magnetically doped with Fe is presented. Doping of alloyed CdTeS nanocrystals with Fe was achieved in situ using a simple hydrothermal method. The magnetic quantum dots (MQDs) were capped with NAcetyl-Cysteine (NAC) ligands, containing thiol and carboxylic acid functional groups to provide stable aqueous dispersion. The optical and magnetic properties of the Fe doped MQDs were characterized using several techniques. The synthesized MQDs are tuned to emit in the Vis-NIR (530-738 nm) wavelength regime and have high quantum yields (67.5-10%). NIR emitting (738 nm) MQDs having 5.6 atomic% Fe content exhibited saturation magnetization of 85 emu/gm[Fe] at room temperature. Proton transverse relaxivity of the Fe doped MQDs (738 nm) at 4.7 T was determined to be 3.6 mM−1s−1. The functional evaluation of NIR MQDs has been demonstrated using phantom and in vitro studies. These water dispersible, NIR emitting and MR contrast producing Fe doped CdTeS MQDs, in unagglomerated form, have the potential to act as multimodal contrast agents for tracking live cells. PMID:24634776

  3. Effect of Fe-doping on nonlinear optical responses and carrier trapping dynamics in GaN single crystals

    SciTech Connect

    Fang, Yu; Yang, Junyi; Yang, Yong; Zhou, Feng; Wu, Xingzhi; Xiao, Zhengguo; Song, Yinglin

    2015-08-03

    We presented a quantitative study on the Fe-doping concentration dependence of optical nonlinearities and ultrafast carrier dynamics in Fe-doped GaN (GaN:Fe) single crystals using picosecond Z-scan and femtosecond pump-probe with phase object techniques under two-photon excitation. In contrast to the two-photon absorption that was found to be independent on the Fe-doping, the nonlinear refraction decreased with the Fe concentration due to the fast carrier trapping effect of Fe{sup 3+}/Fe{sup 2+} deep acceptors, which simultaneously acted as an efficient non-radiative recombination channels for excess carriers. Remarkably, compared to that of Si-doped GaN bulk crystal, the free-carrier refraction effect in GaN:Fe crystals was found to be enhanced considerably since Fe-doping and the effective carrier lifetime (∼10 ps) could be tuned over three orders of magnitude at high Fe-doping level of 1 × 10{sup 19 }cm{sup −3}.

  4. Doping concentration driven morphological evolution of Fe doped ZnO nanostructures

    SciTech Connect

    Sahai, A.; Goswami, N.; Kumar, Y.; Agarwal, V.; Olive-Méndez, S. F.

    2014-10-28

    In this paper, systematic study of structural, vibrational, and optical properties of undoped and 1-10 at.% Fe doped ZnO nanostructures, synthesized adopting chemical precipitation route, has been reported. Prepared nanostructures were characterized employing an assortment of microscopic and spectroscopic techniques, namely Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX) Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Micro-Raman Spectroscopy (μRS), and UV-visible and Photoluminescence (PL) spectroscopy. With Fe incorporation, a gradual morphological transformation of nanostructures is demonstrated vividly through SEM/TEM characterizations. Interestingly, the morphology of nanostructures evolves with 1–10 at. % Fe doping concentration in ZnO. Nanoparticles obtained with 1 at. % Fe evolve to nanorods for 3 at. % Fe; nanorods transform to nanocones (for 5 at. % and 7 at. % Fe) and finally nanocones transform to nanoflakes at 10 at. % Fe. However, at all these stages, concurrence of primary hexagonal phase of Zn{sub 1-x}Fe{sub x}O along with the secondary phases of cubic ZnFe{sub 2}O{sub 4} and rhombohedric Fe{sub 2}O{sub 3}, is revealed through XRD analysis. Based on collective XRD, SEM, TEM, and EDX interpretations, a model for morphological evolution of nanostructures was proposed and the pivotal role of Fe dopant was deciphered. Furthermore, vibrational properties analyzed through Raman and FTIR spectroscopies unravel the intricacies of formation and gradual enhancement of secondary phases with increased Fe concentration. UV-visible and PL spectroscopic analyses provided further insight of optical processes altering with Fe incorporation. The blue shift and gradual quenching of visible photoluminescence with Fe doping was found in accordance with structural and vibrational analyses and explicated accordingly.

  5. Characterization of the Fe-Doped Mixed-Valent Tunnel Structure 2 Manganese Oxide KOMS-2

    SciTech Connect

    Hanson J. C.; Shen X.; Morey A.M.; Liu J.; Ding Y.; Cai J.; Durand J.; Wang Q.; Wen W.; Hines W.A.; Bai J.; Frenkel A.I.; Reiff W.; Aindow M.; Suib S.L.

    2011-11-10

    A sol-gel-assisted combustion method was used to prepare Fe-doped manganese oxide octahedral molecular sieve (Fe-KOMS-2) materials with the cryptomelane structure. Characterization of the nanopowder samples over a wide range of Fe-doping levels (0 {le} Fe/Mn {le} 1/2) was carried out using a variety of experimental techniques. For each sample, Cu K{alpha} XRD and ICP-AES were used to index the cryptomelane structure and determine the elemental composition, respectively. A combination of SEM and TEM images revealed that the morphology changes from nanoneedle to nanorod after Fe doping. Furthermore, TGA scans indicated that the thermal stability is also enhanced with the doping. Anomalous XRD demonstrated that the Fe ions replace the Mn ions in the cryptomelane structure, particularly in the (211) planes, and results in a lattice expansion along the c axis, parallel to the tunnels. Reasonable fits to EXAFS data were obtained using a model based on the cryptomelane structure. Moessbauer spectra for selected Fe-KOMS-2 samples indicated that the Fe is present as Fe{sup 3+} in an octahedral environment similar to Mn in the MnO{sub 6} building blocks of KOMS-2. Magnetization measurements detected a small amount of {gamma}-Fe{sub 2}O{sub 3} second phase (e.g., 0.6 wt % for the Fe/Mn = 1/10 sample), the vast majority of the Fe being in the structure as Fe{sup 3+} in the high-spin state.

  6. Interplay between chemical state, electric properties, and ferromagnetism in Fe-doped ZnO films

    SciTech Connect

    Chen, G.; Peng, J. J.; Song, C.; Zeng, F.; Pan, F.

    2013-03-14

    Valence state of Fe ions plays an important role in the physical properties of Fe doped ZnO films. Here, a series of Zn{sub 1-x}Fe{sub x}O films with different Fe concentrations (x = 0, 2.3, 5.4, 7.1, and 9.3 at. %) were prepared to investigate their structural, piezoelectric, ferroelectric, bipolar resistive switching properties, and electrical-control of ferromagnetism at room temperature. The structure characterizations indicate that the chemical state of Fe ions substituting Zn{sup 2+} site changes from Fe{sup 3+} to Fe{sup 2+} with the increase of Fe dopant concentration. We found enhanced piezoelectric and ferroelectric properties in Zn{sub 0.977}Fe{sub 0.023}O films with more Fe{sup 3+} due to the smaller Fe{sup 3+} ionic size in comparison with Zn{sup 2+} while the increase of Fe{sup 2+} concentration by a larger amount of Fe dopant results in the worse ferroelectric and piezoelectric performance. All Pt/Zn{sub 1-x}Fe{sub x}O/Pt devices show bipolar resistive switching properties. Especially, devices with lower Fe dopant concentration exhibit better endurance properties due to their higher crystalline quality. The variation of oxygen vacancies during resistive switching provides an opportunity to tune ferromagnetism of Fe-doped ZnO films, giving rise to the integration of charge and spin into a simple Pt/Zn{sub 1-x}Fe{sub x}O/Pt devices. The multifunctional properties of Fe-doped ZnO films are promising for communication systems and information storage devices.

  7. ALCHEMI of Fe-doped B2-ordered NiAl alloys with different doping levels

    SciTech Connect

    Anderson, I.M.; Bentley, J.; Duncan, A.J.

    1994-09-01

    The ALCHEMI technique yields exact expressions for best-fit parameters in terms of ionization localization constants and site distributions of 3 elements distributed over two sublattices. In this paper, a graphical plotting technique is applied to Fe-doped NiAl B2-ordered alloys Ni{sub 0.5-x}Fe{sub x}Al{sub 0.5}, with x=0.02 or 0.10. The thin foil samples were examined in an electron microscope with an x-ray spectrometer.

  8. Influence of Fe-Doping on the Structural, Morphological, Optical, Magnetic and Antibacterial Effect of ZnO Nanostructures.

    PubMed

    Basith, N Mohamed; Vijaya, J Judith; Kennedy, L John; Bououdina, M; Shenbhagaraman, R; Jayavel, R

    2016-02-01

    Pure and Fe-doped ZnO nanostructures with different weight ratios (0.5, 1.0, 1.5, and 2.0 at wt% of Fe) were successfully synthesized by a facile microwave combustion method using urea as a fuel. The detailed structural characterization was performed by means of X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). XRD patterns refined by the Rietveld method indicated that Fe-doped ZnO have a single pure phase with wurtzite structure, suggesting that Fe ions are successfully incorporated into ZnO crystal lattice by occupying Zn ionic sites. Interestingly, the morphology was found to change substantially from grains to nanoflakes and then into nanorods with the variation of Fe-content. The optical band gap estimated using DRS was found to be red-shifted from 3.220 eV for the pure ZnO nanostructures, then decreases up to 3.200 eV with increasing Fe-content. Magnetic studies showed that Fe-doped ZnO nanostructures exhibit room temperature ferromagnetism (RTFM) and the saturation magnetization attained a maximum value of 8.154 x 10(-3) emu/g for the highest Fe-content. The antibacterial activity of pure and Fe-doped ZnO nanostructures against a Gram-positive bacteria and Gram-negative bacteria was investigated. Pure ZnO and Fe-doped ZnO exhibited antibacterial activity, but it was considerably more effective in the 1.5 wt% Fe-doped ZnO nanostructures. PMID:27433623

  9. Effects of calcining temperature on photocatalytic activity of Fe-doped sulfated titania.

    PubMed

    Yang, Ying; Tian, Congxue

    2012-01-01

    Using industrial titanyl sulfate as a raw material, Fe-doped sulfated titania (FST) photocatalysts were prepared by using the one-step thermal hydrolysis method and characterized using XRD, SEM, TGA-DSC, FTIR, UV-Vis DRS and N(2) adsorption-desorption techniques. The effects of calcining temperature on the structure of the titania were investigated. The photocatalytic activity of the FST was evaluated using the photodegradation of methylene blue and photooxidation of phenol in aqueous solutions under UV and visible light irradiation, respectively. The results evinced that Ti(4+) is substituted by Fe(3+) in titania lattice and forms impurity level within the band gap of titania, which consequently induces the visible light absorption and visible-light-driven photocatalytic activity. The synergistic effects of Fe-doping and sulfation are beneficial to the efficient separation of the photogenerated carriers and also improve the quantum efficiency of photocatalysis. In addition, Brönsted acidity arisen from the strong inductive effect of sulfate is also conducive to enhancing the photocatalytic performance of FST. However, when the calcining temperature is higher than 800°C, sulfur species and surface hydroxyl groups decompose and desorb from FST and the specific surface area decreases sharply. Moreover, severe sintering and rutile phase formation occur simultaneously. All these are detrimental to photocatalytic activity of FST. PMID:22486465

  10. Strain-Induced Extrinsic High-Temperature Ferromagnetism in the Fe-Doped Hexagonal Barium Titanate

    PubMed Central

    Zorko, A.; Pregelj, M.; Gomilšek, M.; Jagličić, Z.; Pajić, D.; Telling, M.; Arčon, I.; Mikulska, I.; Valant, M.

    2015-01-01

    Diluted magnetic semiconductors possessing intrinsic static magnetism at high temperatures represent a promising class of multifunctional materials with high application potential in spintronics and magneto-optics. In the hexagonal Fe-doped diluted magnetic oxide, 6H-BaTiO3-δ, room-temperature ferromagnetism has been previously reported. Ferromagnetism is broadly accepted as an intrinsic property of this material, despite its unusual dependence on doping concentration and processing conditions. However, the here reported combination of bulk magnetization and complementary in-depth local-probe electron spin resonance and muon spin relaxation measurements, challenges this conjecture. While a ferromagnetic transition occurs around 700 K, it does so only in additionally annealed samples and is accompanied by an extremely small average value of the ordered magnetic moment. Furthermore, several additional magnetic instabilities are detected at lower temperatures. These coincide with electronic instabilities of the Fe-doped 3C-BaTiO3-δ pseudocubic polymorph. Moreover, the distribution of iron dopants with frozen magnetic moments is found to be non-uniform. Our results demonstrate that the intricate static magnetism of the hexagonal phase is not intrinsic, but rather stems from sparse strain-induced pseudocubic regions. We point out the vital role of internal strain in establishing defect ferromagnetism in systems with competing structural phases. PMID:25572803

  11. Preparation of Fe-doped colloidal SiO(2) abrasives and their chemical mechanical polishing behavior on sapphire substrates.

    PubMed

    Lei, Hong; Gu, Qian; Chen, Ruling; Wang, Zhanyong

    2015-08-20

    Abrasives are one of key influencing factors on surface quality during chemical mechanical polishing (CMP). Silica sol, a widely used abrasive in CMP slurries for sapphire substrates, often causes lower material removal rate (MRRs). In the present paper, Fe-doped colloidal SiO2 composite abrasives were prepared by a seed-induced growth method in order to improve the MRR of sapphire substrates. The CMP performance of Fe-doped colloidal SiO2 abrasives on sapphire substrates was investigated using UNIPOL-1502 CMP equipment. Experimental results indicate that the Fe-doped colloidal SiO2 composite abrasives exhibit lower surface roughness and higher MRR than pure colloidal SiO2 abrasives for sapphire substrates under the same testing conditions. Furthermore, the acting mechanism of Fe-doped colloidal SiO2 composite abrasives in sapphire CMP was analyzed by x-ray photoelectron spectroscopy. Analytical results show that the Fe in the composite abrasives can react with the sapphire substrates to form aluminum ferrite (AlFeO3) during CMP, which promotes the chemical effect in CMP and leads to improvement of MRR. PMID:26368752

  12. Novel Fe doped mesoporous TiO 2 microspheres: Ultrasonic-hydrothermal synthesis, characterization, and photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Li, Haibin; Liu, Guocong; Chen, Shuguang; Liu, Qicheng

    2010-04-01

    Novel Fe doped mesoporous TiO 2 microspheres were fabricated by an ultrasonic-hydrothermal method when tetrabutyl titanate was used as a precursor and octadecylamine was used as a structure-directing agent. The mesoporous materials were characterized by XRD, SEM, TEM, N 2 adsorption-desorption measurements, XPS, FL, and UV-vis. The results suggest that both ultrasonic treatment and hydrothermal procedure are critical for the fabrication of Fe doped mesoporous TiO 2 microspheres with a combination of regular morphology, large specific surface area, high crystallinity, and high thermal stability. Low-angle XRD and TEM images indicate that the disordered wormhole-like mesostructure of Fe doped TiO 2 microspheres with diameters of about 300-400 nm is actually formed by the agglomerization of nanoparticles with an average size of about 10 nm. The photocatalytic activity of Fe doped mesoporous TiO 2 microspheres was evaluated by the photodegradation of methyl orange. A small amount of Fe 3+ can obviously enhance their photocatalytic activity. The optimal atomic ratio of Fe to Ti for photocatalytic activity is about 0.5 at%.

  13. XRD analysis of undoped and Fe doped TiO{sub 2} nanoparticles by Williamson Hall method

    SciTech Connect

    Bharti, Bandna; Barman, P. B.; Kumar, Rajesh

    2015-08-28

    Undoped and Fe doped titanium dioxide (TiO{sub 2}) nanoparticles were synthesized by sol-gel method at room temperature. The synthesized samples were annealed at 500°C. For structural analysis, the prepared samples were characterized by X-ray diffraction (XRD). The crystallite size of TiO{sub 2} and Fe doped TiO{sub 2} nanoparticles were calculated by Scherer’s formula, and was found to be 15 nm and 11 nm, respectively. Reduction in crystallite size of TiO{sub 2} with Fe doping was observed. The anatase phase of Fe-doped TiO{sub 2} nanoparticles was also confirmed by X-ray diffraction. By using Williamson-Hall method, lattice strain and crystallite size were also calculated. Williamson–Hall plot indicates the presence of compressive strain for TiO{sub 2} and tensile strain for Fe-TiO{sub 2} nanoparticles annealed at 500°C.

  14. Aminothiazole-derived N,S,Fe-doped graphene nanosheets as high performance electrocatalysts for oxygen reduction.

    PubMed

    Chen, Chi; Yang, Xiao-Dong; Zhou, Zhi-You; Lai, Yu-Jiao; Rauf, Muhammad; Wang, Ying; Pan, Jing; Zhuang, Lin; Wang, Qiang; Wang, Yu-Cheng; Tian, Na; Zhang, Xin-Sheng; Sun, Shi-Gang

    2015-12-14

    N,S,Fe-doped graphene nanosheets were directly synthesized from aminothiazole, a precursor molecule that contains N and S atoms, through Fe catalysis under heat treatment. The graphene nanosheets exhibited high electrocatalytic activity toward oxygen reduction reaction in both acidic and alkaline media during rotating disk electrode half-cell and fuel cell tests. PMID:26451800

  15. Selenium Sulfide

    MedlinePlus

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium ...

  16. Importance of doping and frustration in itinerant Fe-doped Cr2Al

    SciTech Connect

    Susner, M. A.; Parker, D. S.; Sefat, A. S.

    2015-05-12

    We performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x≈0.125 after which point increasing paramagnetic behavior is exhibited. Moreover, this is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculations explain that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  18. Magnetization reversal and negative volume thermal expansion in Fe doped Ca2RuO4

    NASA Astrophysics Data System (ADS)

    Qi, T. F.; Yuan, S. J.; Ye, F.; Chi, S.; Terzic, J.; Zhang, H.; Zhao, Z.; Liu, X.; Parkin, S.; Mao, W. L.; Cao, G.

    We report structural, magnetic, transport and thermal properties of single-crystal Ca2Ru1-xFexO4 (0 <= x <= 0.2) as functions of pressure, magnetic field and temperature. The central findings of this work are a pronounced magnetization reversal and a negative thermal expansion that are induced by Fe doping. Our results including neutron diffraction data suggest that the magnetization reversal is primarily a result of different temperature dependences of two antiparallel, competing Ru and Fe sublattices and that the negative thermal expansion is achieved via magnetic and metal-insulator transitions. We will present and discuss our results with comparison drawn with relevant systems. This work was supported by the NSF via Grant No. DMR-1265162.

  19. Enhanced multiferroic characteristics in Fe-doped BiTiO ceramics

    NASA Astrophysics Data System (ADS)

    Chen, X. Q.; Yang, F. J.; Cao, W. Q.; Wang, H.; Yang, C. P.; Wang, D. Y.; Chen, K.

    2010-07-01

    Modification of Bi 4Ti 3O 12 multiferroic ceramics prepared by a conventional solid state reaction method were investigated by substituting Ti partly with Fe. The introduction of Fe does not change the layered perovskite structure of Bi 4Ti 3O 12. Upon increasing Fe content, the remnant polarization of the samples is enhanced. The magnetism of the ceramics at room temperature develops from diamagnetism to weak ferromagnetism with increasing Fe doping. The largest variations of 15% and 6% in remnant polarization and magnetization, achieved in a Bi 4Ti 1Fe 2O 12-δ sample after poling it in a magnetic field at 1 T and a DC electric field at 30 kV/cm for 10 min, are evidence of magnetoelectric coupling between the electric dipoles and magnetic dipoles at room temperature. The present results suggest a new candidate for a room temperature multiferroic material with enhanced properties.

  20. Structure and magnetism of Fe-doped SnO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Adhikari, R.; Das, A. K.; Karmakar, D.; Rao, T. V. Chandrasekhar; Ghatak, J.

    2008-07-01

    SnO2 nanoparticles doped with Fe of different concentrations were synthesized by a chemical coprecipitation method. After calcination at 600°C , the samples were characterized using x-ray diffraction (XRD), transmission electron microscope (TEM), and superconducting quantum interference device magnetometer. XRD shows that the solubility of Fe in SnO2 ( Sn1-xFexO2 : primary phase where Fe substitutes Sn in SnO2 matrix) is less than 7.5% (x<0.075) and Fe2O3 (hematite) or (Fe1-ySny)2O3 (where Sn substitutes Fe in Fe2O3 matrix) is evolved as a secondary phase for x≥0.075 along with Sn1-xFexO2 (primary phase). TEM shows that the particles are crystalline and of size in the nanometric regime (10±3nm) . The M(T) and M(H) studies indicated an antiferromagnetic (AFM) interaction in 3% and 5% (atomic weight) Fe-doped SnO2 nanoparticles. The observed AFM interaction can be explained by the bound magnetic polaron model for insulating diluted magnetic semiconductor systems. It is seen that the strength of AFM interaction reduces with increase in doping concentration. On the other hand, 7.5% Fe-doped SnO2 nanoparticles show the ferromagnetic interaction, but the origin of the observed ferromagnetism is identified due to the presence of (Fe1-ySny)2O3 as a secondary phase.

  1. Comparison of the low-temperature specific heat of Fe- and Co-doped Bi1.8Pb0.2Sr2Ca(Cu1-xMx)2O8 (M=Fe or Co): Anomolously enhanced electronic contribution due to Fe doping

    NASA Astrophysics Data System (ADS)

    Yu, M. K.; Franck, J. P.

    1996-04-01

    Specific-heat data of Fe-doped Bi1.8Pb0.2Sr2Ca(Cu1-xFex)2O8 in the range 2-20 K are presented for x=1, 2, 4, 6, and 8 %. The data are compared with our previous measurements on Co-doped bismuth-strontium-calcium-copper oxide superconductors of nominal composition Bi2Sr2CaCu2O8 (BISCO 2212). Both Fe and Co are magnetic substitutions with effective moments close to their free-ion value. In the normal state the magnetic susceptibility increases by more than a factor 2 over the doping range due to effective-mass enhancement. In the superconducting state both ions act as magnetic pair breakers. For Co doping the normal-state linear term γ is observed, enhanced due to the effective-mass increase. For Fe doping we observe a large anomalous contribution to the electronic specific heat starting near 15 K and leading at the lowest temperature to a linear term near γ0=72 mJ/mole K2 (1 mole=1 formula unit). The anomalous term is typical of heavy fermion behavior. Comparison with specific-heat data of Co-doped BISCO 2212 suggests that hybridization between 3d electrons of the dopant and the planar carriers is more effective for Fe doping than for Co doping.

  2. Electrical properties of lead-free Fe-doped niobium-rich potassium lithium tantalate niobate single crystals

    NASA Astrophysics Data System (ADS)

    Li, Yang; Li, Jun; Zhou, Zhongxiang; Guo, Ruyan; Bhalla, Amar S.

    2013-12-01

    Lead-free, 0.025 wt% Fe-doped niobium-rich potassium lithium tantalate niobate Fe: K0.95Li0.05Ta1-xNbxO3 single crystals have been grown by the top-seeded melt growth method. All the transition temperatures have been determined by the dielectric constant and loss-dependent temperature. The spontaneous polarizations computed by the integration of pyroelectric coefficients over all the temperatures are consistent with the results of the P-E hysteresis loops. The piezoelectric constants and electromechanical coupling factors are attractive among lead-free piezoelectric materials. With suitable Fe-doping, the electrical properties of KLTN single crystals have been improved overall and can be compared to those of the current important lead-based piezoelectric materials.

  3. Understanding the role of iron in the magnetism of Fe doped ZnO nanoparticles.

    PubMed

    Beltrán, J J; Barrero, C A; Punnoose, A

    2015-06-21

    The actual role of transition metals like iron in the room temperature ferromagnetism (RTFM) of Fe doped ZnO nanoparticles is still an unsolved problem. While some studies concluded that the Fe ions participate in the magnetic interaction, others in contrast do not believe Fe to play a direct role in the magnetic exchange interaction. To contribute to the understanding of this issue, we have carefully investigated the structural, optical, vibrational and magnetic properties of sol-gel synthesized Zn1-xFexO (0 < x < 0.10) nanoparticles. No Fe(2+) was detected in any sample. We found that high spin Fe(3+) ions are substitutionally incorporated at the Zn(2+) in the tetrahedral-core sites and in pseudo-octahedral surface sites in ZnO. Superficial OH(-) was observed in all samples. For x ≤ 0.03, an increment in Fe doping concentration decreased a and c lattice parameters, average Zn-O bond length, average crystallite size and band gap; while it increased the degree of distortion and quadrupole splitting. Undoped ZnO nanoparticles exhibited very weak RTFM with a saturation magnetization (Ms) of ∼0.47 memu g(-1) and this value increased to ∼2.1 memu g(-1) for Zn0.99Fe0.01O. Very interestingly, the Ms for Zn0.99Fe0.01O and Zn0.97Fe0.03O increased by a factor of about ∼2.3 by increasing annealing for 1 h to 3 h. For x ≥ 0.05, ferrimagnetic disordered spinel ZnFe2O4 was formed and this phase was found to become more ordered with increasing annealing time. Fe does not contribute directly to the RTFM, but its presence promoted the formation of additional single charged oxygen vacancies, zinc vacancies, and more oxygen-ended polar terminations at the nanoparticle surface. These defects, which are mainly superficial, altered the electronic structure and are considered as the main sources of the observed ferromagnetism. PMID:25994044

  4. Effects of Fe doping on the structures and properties of hexagonal birnessites - Comparison with Co and Ni doping

    NASA Astrophysics Data System (ADS)

    Yin, Hui; Liu, Fan; Feng, Xionghan; Hu, Tiandou; Zheng, Lirong; Qiu, Guohong; Koopal, Luuk K.; Tan, Wenfeng

    2013-09-01

    Fe-doped hexagonal birnessite was synthesized by adding Fe3+ to the initial reactants, and the effects of Fe doping on the structures and properties of birnessite were investigated and compared with the effects of Co and Ni doping. The underlying mechanisms controlling the incorporation of transition metals (TMs) into the birnessite structure were proposed. Compared to the un-doped control, Fe-doped birnessite has weaker crystallinity, i.e., less stacking of the phyllomanganate sheets in the c direction, and larger surface area. Combination of X-ray photoelectron spectroscopy (XPS) and Mn K-edge XANES and EXAFS spectra demonstrates that Fe doping decreases the Mn average oxidation state (AOS) but has little effect on the basic layer structure and local Mn environments. Fe(III) located in the birnessite layers exhibits high-spin (HS) configuration whereas layer Mn(III) and Co(III) plausibly adopt low-spin (LS) state. The TMs decrease the thickness of birnessite plate crystals along the c axis and affect the unit cell parameter b in the order Fe > Ni > Co. Co and Fe incorporate into the birnessite layers by substitution for Mn(IV) while Ni substitutes for Mn(III). The substitution of TMs into the birnessite layers is governed by the coordination radius (CR), crystal field stabilization energy (CFSE) and oxidation state of the TMs. The variations in potassium contents in doped birnessites together with TM K-edge EXAFS data indicate that most of the Fe (˜81-82%) or Ni (˜66-76%) incorporated into the birnessite structure exists in the interlayer regions, while most of the Co (˜71-80%) occurs in the manganese layers. The compatibility of these TM ions in the birnessite layers is in the order Co > Ni > Fe. The smaller the difference between the CR of Fe, Co or Ni and Mn(IV) or Mn(III), the more dopants are compatible within the Mn layers.

  5. Enhancement of Photo-Oxidation Activities Depending on Structural Distortion of Fe-Doped TiO2 Nanoparticles.

    PubMed

    Kim, Yeonwoo; Yang, Sena; Jeon, Eun Hee; Baik, Jaeyoon; Kim, Namdong; Kim, Hyun Sung; Lee, Hangil

    2016-12-01

    To design a high-performance photocatalytic system with TiO2, it is necessary to reduce the bandgap and enhance the absorption efficiency. The reduction of the bandgap to the visible range was investigated with reference to the surface distortion of anatase TiO2 nanoparticles induced by varying Fe doping concentrations. Fe-doped TiO2 nanoparticles (Fe@TiO2) were synthesized by a hydrothermal method and analyzed by various surface analysis techniques such as transmission electron microscopy, Raman spectroscopy, X-ray diffraction, scanning transmission X-ray microscopy, and high-resolution photoemission spectroscopy. We observed that Fe doping over 5 wt.% gave rise to a distorted structure, i.e., Fe2Ti3O9, indicating numerous Ti(3+) and oxygen-vacancy sites. The Ti(3+) sites act as electron trap sites to deliver the electron to O2 as well as introduce the dopant level inside the bandgap, resulting in a significant increase in the photocatalytic oxidation reaction of thiol (-SH) of 2-aminothiophenol to sulfonic acid (-SO3H) under ultraviolet and visible light illumination. PMID:26822520

  6. Structural, optical, and magnetic properties of Mn and Fe-doped Co{sub 3}O{sub 4} nanoparticles

    SciTech Connect

    Stella, C. Soundararajan, N.; Ramachandran, K.

    2015-08-15

    Mn and Fe-doped Co{sub 3}O{sub 4} nanoparticles were prepared by a simple precipitation method. The synthesized particles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and vibrating sample magnetometer (VSM) techniques. XRD analysis showed the cubic structure of Co{sub 3}O{sub 4}. SEM and TEM images confirmed the formation of interconnected nanoparticles. Mn and Fe-doped Co{sub 3}O{sub 4} showed broad absorption in the visible region compared to undoped sample and the band gap values are red shifted. Five Raman active modes were observed from the Raman spectra. FTIR spectra confirmed the spinel structure of Co{sub 3}O{sub 4} and the doping of Mn and Fe shifts the vibrational modes to lower wave number region. The magnetic measurements confirmed that Fe-doped Co{sub 3}O{sub 4} shows a little ferromagnetic behavior compared to undoped and Mn-doped Co{sub 3}O{sub 4}, which could be related to the uncompensated surface spins and the finite size effects.

  7. Enhancement of Photo-Oxidation Activities Depending on Structural Distortion of Fe-Doped TiO2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kim, Yeonwoo; Yang, Sena; Jeon, Eun Hee; Baik, Jaeyoon; Kim, Namdong; Kim, Hyun Sung; Lee, Hangil

    2016-01-01

    To design a high-performance photocatalytic system with TiO2, it is necessary to reduce the bandgap and enhance the absorption efficiency. The reduction of the bandgap to the visible range was investigated with reference to the surface distortion of anatase TiO2 nanoparticles induced by varying Fe doping concentrations. Fe-doped TiO2 nanoparticles (Fe@TiO2) were synthesized by a hydrothermal method and analyzed by various surface analysis techniques such as transmission electron microscopy, Raman spectroscopy, X-ray diffraction, scanning transmission X-ray microscopy, and high-resolution photoemission spectroscopy. We observed that Fe doping over 5 wt.% gave rise to a distorted structure, i.e., Fe2Ti3O9, indicating numerous Ti3+ and oxygen-vacancy sites. The Ti3+ sites act as electron trap sites to deliver the electron to O2 as well as introduce the dopant level inside the bandgap, resulting in a significant increase in the photocatalytic oxidation reaction of thiol (-SH) of 2-aminothiophenol to sulfonic acid (-SO3H) under ultraviolet and visible light illumination.

  8. Influence of Fe doping on the structural, optical and magnetic properties of ZnS diluted magnetic semiconductor

    NASA Astrophysics Data System (ADS)

    Saikia, D.; Raland, RD.; Borah, J. P.

    2016-09-01

    Fe doped ZnS nanoparticles with different concentrations of Fe, synthesized by microwave assisted co-precipitation method have been reported. The incorporation of Fe2+ and Fe3+ ions into ZnS lattice are confirmed by X-ray diffraction (XRD) and Electron Paramagnetic resonance (EPR) study. XRD and High Resolution Transmission electron Microscope (HRTEM) results confirm the phase purity of the samples and indicate a reduction of the particle size with increase in Fe concentration. EDAX analysis confirms the presence of Zn, S and Fe in the samples. A yellow-orange emission peak is observed in Photoluminescence (PL) spectra which exhibits the Characteristic 4T2 (4G)-6A1 (6S) transition of Fe3+ ion. The room temperature magnetic studies as analyzed from M-H curves were investigated from vibrating samples magnetometer (VSM) which shows a weak ferro and superparamagnetic like behavior in 1% and 3% Fe-doped ZnS nanocrystals, whereas; at 10% Fe-doping concentrations, antiferromagnetism behavior is achieved. The ZFC-FC measurement reveals that the blocking temperature of the nanoparticle is above the room temperature.

  9. Strong effect of low-dimensional Fe-doped cobalt niobate on a strongly ferrimagnetic system

    NASA Astrophysics Data System (ADS)

    Nlebedim, Cajetan; Jiles, David

    2015-03-01

    In this work, the first investigation of the effect of Fe-doped cobalt niobate (CoNb2O6) imbedded in the matrix of a strongly ferrimagnetic cobalt-iron oxide, is presented. The temperature dependence of the magnetic properties and how they change with variations in the concentration of CoNb2O6 is also presented. CoNb2O6 is a prototypical low-dimensional material belonging to the pyrochlore-type AB2O6 systems. Its low-dimensional magnetic characteristics can help in understanding the magnetic properties of higher order systems. It has been investigated for applications in resonators and capacitors. This work shows that the magnetization of the ferrimagnetic phase is strongly affected by the concentration of Co ions in the low-dimensional phase, below 15 K but changes in coercivity with temperature were predominantly due to the ferrimagnetic phase. The systematic variation in the concentration of both phases and the cation ratio in each phase, enable us to understand the variation of the magnetic properties with temperature. This work provides useful insights into tuning the magnetism in strongly magnetic materials with transition metal AB2O6 systems imbedded in their matrices. This work was supported by the USDoE, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. The research was performed at Ames Laboratory, operated for the USDoE by Iowa State University (Contract # DE-AC02-07CH11358).

  10. Preparation and Charge Density in (Co, Fe)-Doped La-Ca-Based Chromite

    NASA Astrophysics Data System (ADS)

    Saravanan, R.; Thenmozhi, N.; Fu, Yen-Pei

    2016-05-01

    Transition metal-doped lanthanum chromites (La0.8Ca0.2)(Cr0.9-x Co0.1Fe x )O3 (x = 0.03, 0.06, 0.09, 0.12) have been synthesized by solid state reaction method. The synthesized samples were characterized for their structural properties using powder x-ray diffraction analysis, which shows that the grown samples are orthorhombic in structure with single phase. The nature of bonding and the charge distribution of the grown samples have been analyzed by maximum entropy method. Further, the samples were characterized for their optical and magnetic properties using ultraviolet-visible spectra and vibrating sample magnetometry. The microstructural studies were carried by scanning electron microscopy/electron dispersive x-ray spectroscopy techniques. From the optical absorption spectra, it was found that the energy band gap of the samples ranges from 2.135 eV to 2.405 eV. From vibrating sample magnetometer measurements, ferromagnetic like behaviour with large coercive field was observed for Fe doping concentration of x = 0.12. Since the doped lanthanum chromites have good mechanical properties and electrical conductivity at high temperature, these materials are used in solid oxide fuel cells.

  11. Correlation between oxygen vacancies and magnetism in Fe-doped In2O3 films

    NASA Astrophysics Data System (ADS)

    An, Yukai; Wang, Shiqi; Feng, Deqiang; Wu, Zhonghua; Liu, Jiwen

    2013-07-01

    Correlation between oxygen vacancies and magnetic property in the as-deposited and annealed (In0.93Fe0.07)2O3 films has been investigated by X-ray diffraction, magnetization measurement, X-ray absorption near-edge structure and extend X-ray absorption fine structure. Magnetic measurement reveals that clear room temperature ferromagnetism is observed for the as-deposited film, in which the doped Fe ions substitute for In sites of the In2O3 lattice and Fe-related secondary phases or clusters as the source of ferromagnetism is safely ruled out. After high-temperature annealing in air, the crystalline structure of film and occupation sites of Fe ions keep unchanged, whereas the magnetic property has a dramatic decrease. Based on X-ray absorption near-edge spectroscopy analysis and multiple-scattering theoretical calculations, it is found that the content of oxygen vacancy of film remarkably decreases, even disappears by annealing in air, which resulting in greatly decreasing the ferromagnetism. These results further provide strong evidence that the oxygen vacancies play an important role in activating the ferromagnetic interactions in Fe-doped In2O3.

  12. Characterization of transparent superconductivity Fe-doped CuCrO2 delafossite oxide

    NASA Astrophysics Data System (ADS)

    Taddee, Chutirat; Kamwanna, Teerasak; Amornkitbamrung, Vittaya

    2016-09-01

    Delafossite CuCr1-xFexO2 (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 CuCr1-xFexO2 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 CuCrO2 samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe3+ for Cr3+ produced a mixed effect on the magnetic properties of CuCrO2 delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr1-xFexO2 with a superconducting transition up to 118 K.

  13. Structural and magnetic characterization of (TM=Co, Fe) doped SnO2 nanostructures

    NASA Astrophysics Data System (ADS)

    Parra Palomino, A.; Rzchowski, M. S.; Perales Perez, O.

    2009-03-01

    Recent indications of intrinsic room-temperature (RT) ferromagnetism in transition metal doped-SnO2 have increased its attractiveness as promising material for nano-optoelectronic and spintronics-based devices. A control over dopant speciation and the determination of the size-dependence of the properties at the nanoscale, become then indispensable. We present here the conditions for the room-temperature synthesis of doped SnO2 in ethanol using SnCl2 and LiHO precursors, and the characterization of the resulting bare, Co and Fe- doped SnO2 powders. X-ray diffraction patterns of bare and doped SnO2 showed the formation of an amorphous structure from the produced powder at RT. However, a pure phase of rutile structure was observed when the samples were annealed in air or Ar at 400^oC. 100nm diameter wires were observed after annealing using scanning electron microscopy (SEM). The results of magnetic characterization of the materials using a vibrating sample magnetometer (VSM) will also be presented and discussed.

  14. Structural properties of pure and Fe-doped Yb films prepared by vapor condensation

    SciTech Connect

    Rojas-Ayala, C.; Passamani, E.C.; Suguihiro, N.M.; Litterst, F.J.; Baggio Saitovitch, E.

    2014-10-15

    Ytterbium and iron-doped ytterbium films were prepared by vapor quenching on Kapton substrates at room temperature. Structural characterization was performed by X-ray diffraction and transmission electron microscopy. The aim was to study the microstructure of pure and iron-doped films and thereby to understand the effects induced by iron incorporation. A coexistence of face centered cubic and hexagonal close packed-like structures was observed, the cubic-type structure being the dominant contribution. There is an apparent thickness dependence of the cubic/hexagonal relative ratios in the case of pure ytterbium. Iron-clusters induce a crystalline texture effect, but do not influence the cubic/hexagonal volume fraction. A schematic model is proposed for the microstructure of un-doped and iron-doped films including the cubic- and hexagonal-like structures, as well as the iron distribution in the ytterbium matrix. - Highlights: • Pure and Fe-doped Yb films have been prepared by vapor condensation. • Coexistence of fcc- and hcp-type structures was observed. • No oxide phases have been detected. • Fe-clustering does not affect the fcc/hcp ratio, but favors a crystalline texture. • A schematic model is proposed to describe microscopically the microstructure.

  15. Electrical and optical properties of Fe doped AlGaN grown by molecular beam epitaxy

    SciTech Connect

    Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Kozhukhova, E. A.; Dabiran, A. M.; Chow, P. P.; Wowchak, A. M.; Pearton, S. J.

    2010-01-15

    Electrical and optical properties of AlGaN grown by molecular beam epitaxy were studied in the Al composition range 15%-45%. Undoped films were semi-insulating, with the Fermi level pinned near E{sub c}-0.6-0.7 eV. Si doping to (5-7)x10{sup 17} cm{sup -3} rendered the 15% Al films conducting n-type, but a large portion of the donors were relatively deep (activation energy 95 meV), with a 0.15 eV barrier for capture of electrons giving rise to strong persistent photoconductivity (PPC) effects. The optical threshold of this effect was {approx}1 eV. Doping with Fe to a concentration of {approx}10{sup 17} cm{sup -3} led to decrease in concentration of uncompensated donors, suggesting compensation by Fe acceptors. Addition of Fe strongly suppressed the formation of PPC-active centers in favor of ordinary shallow donors. For higher Al compositions, Si doping of (5-7)x10{sup 17} cm{sup -3} did not lead to n-type conductivity. Fe doping shifted the bandedge luminescence by 25-50 meV depending on Al composition. The dominant defect band in microcathodoluminescence spectra was the blue band near 3 eV, with the energy weakly dependent on composition.

  16. Carrier Mediated Ferromagnetism in Fe-doped SrTiO3

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Lan; Contreras-Guerrero, Rocio; Droopad, Ravi; Lee, Byounghak

    2015-03-01

    The discovery of III-V dilute magnetic semiconductors (DMSs) and the subsequent unsuccessful search for room temperature ferromagnetism in DMSs have motivated researches on alternate dilute magnetic systems. Recent progresses in thin flim growth techniques of perovskite oxides suggest that dilute magnetic oxides (DMOs) can be viable candidates to improve the magnetic properties of DMSs. In this talk we present an ab initio study of Fe-doped SrTiO3. We find that a ferromagnetic ordering among localized Fe t2g spins is mediated by itinerant Fe eg electrons. The exchange interaction between t2g and eg electrons depends on crystal field splitting, on-site electron-electron interaction, and the relative energy of Fe d-ortbitals to oxygen p-orbitals. The exchange coupling and the majority-minority spin splitting decrease with decreasing carrier concentration, confirming that itinerant carriers mediate the ferromagnetism. C. Ma is supported by NSF of China (Grant Nos. 11247023 and 11304218), Jiangsu Qing Lan Project, and Jiangsu Overseas Research & Training Program. R.C.-G, R.D., and B.L. are supported by AFOSR, Award Number FA9550-10-1-0133.

  17. Effect of Fe doping on structural and impedance properties of PZTFN ceramics

    NASA Astrophysics Data System (ADS)

    Kumar, Arvind; Pal, Vijayeta; Mishra, S. K.

    2016-05-01

    An attempts have been made to synthesis the ceramics Pb1-3x/2 Fex(Zr0.52Ti0.48)1-5y/4 NbyO3 abbreviated as (PFZTN) for x = 1-6 mol% and y = 5.5 mol% by a semi-wet route. In the present paper, we have investigated the effect of Fe doping on structural and electrical properties of the PFZTN ceramics. X-ray diffraction (XRD) patterns reveal that PFZTN ceramics are single phase in nature. However, for x = 0.05 and 0.06, a secondary phase appears as discernible from the XRD profiles. Rietveld analysis of the powder diffraction data shows the presence of coexistence of tetragonal (P4mm space group) and rhombohedral phases (R3c space group) occurs near the morphotropic phase boundary (MPB) at x ≥ = 0.05. The log-log plots show that the conductivity increases with increase of temperature. The ac conductivity becomes sensitive at high frequency region and shifted towards higher frequency side with increasing temperature. It is observed that the activation energy (Ea) decreases with increasing frequency. This complex perovskite structure can be used as a multilayer ceramic capacitors and electromechanical transducers.

  18. A close correlation between induced ferromagnetism and oxygen deficiency in Fe doped In 2O 3

    NASA Astrophysics Data System (ADS)

    Singhal, R. K.; Samariya, A.; Kumar, Sudhish; Sharma, S. C.; Xing, Y. T.; Deshpande, U. P.; Shripathi, T.; Saitovitch, E.

    2010-11-01

    We report on the reversible manipulation of room temperature ferromagnetism in Fe (5%) doped In 2O 3 polycrystalline magnetic semiconductor. The X-ray diffraction and photoemission measurements confirm that the Fe ions are well incorporated into the lattice, substituting the In 3+ ions. The magnetization measurements show that the host In 2O 3 has a diamagnetic ground state, while it shows weak ferromagnetism at 300 K upon Fe doping. The as-prepared sample was then sequentially annealed in hydrogen, air, vacuum and finally in air. The ferromagnetic signal shoots up by hydrogenation as well as vacuum annealing and bounces back upon re-annealing the samples in air. The sequence of ferromagnetism shows a close inter-relationship with the behavior of oxygen vacancies ( Vo). The Fe ions tend to a transform from 3+ to 2+ state during the giant ferromagnetic induction, as revealed by photoemission spectroscopy. A careful characterization of the structure, purity, magnetic, and transport properties confirms that the ferromagnetism is due to neither impurities nor clusters but directly related to the oxygen vacancies. The ferromagnetism can be reversibly controlled by these vacancies while a parallel variation of carrier concentration, as revealed by resistance measurements, appears to be a side effect of the oxygen vacancy variation.

  19. Preparation and Charge Density in (Co, Fe)-Doped La-Ca-Based Chromite

    NASA Astrophysics Data System (ADS)

    Saravanan, R.; Thenmozhi, N.; Fu, Yen-Pei

    2016-08-01

    Transition metal-doped lanthanum chromites (La0.8Ca0.2)(Cr0.9- x Co0.1Fe x )O3 ( x = 0.03, 0.06, 0.09, 0.12) have been synthesized by solid state reaction method. The synthesized samples were characterized for their structural properties using powder x-ray diffraction analysis, which shows that the grown samples are orthorhombic in structure with single phase. The nature of bonding and the charge distribution of the grown samples have been analyzed by maximum entropy method. Further, the samples were characterized for their optical and magnetic properties using ultraviolet-visible spectra and vibrating sample magnetometry. The microstructural studies were carried by scanning electron microscopy/electron dispersive x-ray spectroscopy techniques. From the optical absorption spectra, it was found that the energy band gap of the samples ranges from 2.135 eV to 2.405 eV. From vibrating sample magnetometer measurements, ferromagnetic like behaviour with large coercive field was observed for Fe doping concentration of x = 0.12. Since the doped lanthanum chromites have good mechanical properties and electrical conductivity at high temperature, these materials are used in solid oxide fuel cells.

  20. Selenium Sulfide

    MedlinePlus

    Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium sulfide usually is used twice a week for the first ... it is irritating. Rinse off all of the lotion.Do not use this medication on children younger ...

  1. Observation of structural inhomogeneity at degraded Fe-doped SrTiO3 interfaces

    NASA Astrophysics Data System (ADS)

    Ascienzo, D.; Greenbaum, S.; Bayer, T. J. M.; Maier, R.; Randall, C. A.; Ren, Y. H.

    2016-07-01

    We report on the detection of structural inhomogeneity across anode and cathode interfaces in electrically degraded reduced and oxidized Fe-doped SrTiO3 (Fe:STO) single crystals by optical second harmonic generation (SHG) spectroscopy. SHG spectra were collected from several regions across the anode and cathode interfaces in both degraded reduced and oxidized Fe:STO crystals. We identify the formation of defect concentration gradients along both degraded reduced and oxidized anode interfaces. While the broken symmetries decrease from the outer region towards the central region of the reduced anode, the opposite trend is seen in the degraded oxidized anode. These results are attributed to the formation of centrosymmetric Fe4+:Ti4+-O6 octahedral structures in the central region of the reduced sample's degraded anode and non-centrosymmetric Jahn-Teller distortions in the central region of the oxidized sample's degraded anode. The observed changes in SHG intensity from the outer region towards the central region of the degraded cathode interfaces is accompanied by a structural phase transition in the inner and outer regions, marked by strong changes to the s-polarized intensity spectra. We explain the SHG intensity changes by the formation of lower order symmetry Fe3+:Ti3+-O6 structures in the outer region and a modification of the second-order nonlinear susceptibility near the central regions due to the clustering of dissociated oxygen vacancies. These significant structural and spatial inhomogeneities are linked directly to the field-driven migration of oxygen ions and vacancies.

  2. Impregnating Coal With Calcium Carbonate

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  3. Electrically Active Defects in GaN Layers Grown With and Without Fe-doped Buffers by Metal-organic Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Umana-Membreno, G. A.; Parish, G.; Fichtenbaum, N.; Keller, S.; Mishra, U. K.; Nener, B. D.

    2008-05-01

    Electrically active defects in n-GaN films grown with and without an Fe-doped buffer layer have been investigated using conventional and optical deep-level transient spectroscopy (DLTS). Conventional DLTS revealed three well- defined electron traps with activation energies E a of 0.21, 0.53, and 0.8 eV. The concentration of the 0.21 and 0.8 eV defects was found to be slightly higher in the sample without the Fe-doped buffer, whereas the concentration of the 0.53 eV trap was higher in the sample with the Fe-doped buffer. A minority carrier trap with E a ≈ 0.65 eV was detected in both samples using optical DLTS; its concentration was ˜40% higher in the sample without the Fe-doped buffer. Mobility spectrum analysis and multiple magnetic-field measurements revealed that the electron mobility in the topmost layer of both samples was similar, but that the sample without the Fe-doped buffer layer was affected by parallel conduction through underlying layers with lower electron mobility.

  4. Phase conjugation of vector fields by degenerate four-wave mixing in a Fe-doped LiNbO₃.

    PubMed

    Qian, Sheng-Xia; Li, Yongnan; Kong, Ling-Jun; Tu, Chenghou; Wang, Hui-Tian

    2014-08-15

    We propose a method to generate the phase-conjugate wave of the vector field by degenerate four-wave mixing in a c-cut Fe-doped LiNbO3 crystal. We demonstrate experimentally that the phase-conjugate wave of the vector field can be generated. In particular, the phase-conjugate vector field has also the peculiar function of compensating the polarization distortion, as the traditional phase-conjugate scaler field can compensate the phase distortion. PMID:25121905

  5. Ab-initio investigation of spin-dependent transport properties in Fe-doped armchair graphyne nanoribbons

    NASA Astrophysics Data System (ADS)

    GolafroozShahri, S.; Roknabadi, M. R.; Shahtahmasebi, N.; Behdani, M.

    2016-12-01

    An ab-initio study on the spin-polarized transport properties of H-passivated Fe-doped graphyne nanoribbons is presented. All the calculations were based on density functional theory (DFT). Doping single magnetic atom on graphyne nanoribbons leads to metallicity which can significantly improve the conductivity. The currents are not degenerate for both up and down spin electrons and they are considerably spin-polarized. Therefore a relatively good spin-filtering can be expected. For configurations with geometric symmetry spin-rectifying is also observed. Therefore they can be applied as a dual spin-filter or a dual spin-diode in spintronic equipment.

  6. Room-Temperature Magnetocapacitance in Fe-Doped K0.5Na0.5Nb0.95Ta0.05O3 Ceramics

    NASA Astrophysics Data System (ADS)

    Li, Huan; Yang, Wenlong; Li, Yu; Meng, Qingxin; Zhou, Zhongxiang

    2012-10-01

    Ferroelectric and magnetic properties of Fe-doped potassium-sodium tantalate niobate (K0.5Na0.5(Nb0.95Ta0.05)1-xFexO3-x; x = 0 and 0.01) ceramics prepared by the conventional sintering method were investigated. In comparison with pure ceramics, the 0.01 Fe-doped ceramics show magnetic and ferroelectric properties simultaneously at room temperature. The relative dielectric constant significantly decreases after applying a magnetic field for the Fe-doped ceramics, indicating the coupling between ferroelectric and ferromagnetic orders. Magnetocapacitance of -0.77% was observed at room temperature and 50 kHz by the application of a magnetic field of 5000 Oe.

  7. Design and synthesis of two-dimensional porous Fe-doped LiCoPO4 nano-plates as improved cathode for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Fang, Ling; Zhang, Huijuan; Zhang, Yan; Liu, Li; Wang, Yu

    2016-04-01

    Novel two-dimensional (2D) Fe-doped LiCoPO4 nano-plates with porous structure have been successfully fabricated using NH4CoPO4·H2O nanosheets as templates followed by Fe doping and high temperature annealing. The obtained Fe-doped LiCoPO4 nano-plates exhibit several merits in morphology and crystal structure, including well-crystallized feature, porous structure, numerous interconnected pathway, improved electric conductivity and good structural stabilization. All the advantages endow the nano-plates with enhanced electrochemical performance when they are used as cathode materials for lithium ion batteries (LIBs). In this research, high specific capacity, excellent cyclability and outstanding rate capability in electrochemical energy storage are presented. This synthetic strategy is simple, effective, and could be broadly applied in designed synthesis of other electrode materials for LIBs.

  8. Generation of Terahertz Radiation from Fe-doped InGaAsP Using 800 nm to 1550 nm Pulsed Laser Excitation

    NASA Astrophysics Data System (ADS)

    Hatem, O.; Freeman, J. R.; Cunningham, J. E.; Cannard, P. J.; Robertson, M. J.; Linfield, E. H.; Davies, A. G.; Moodie, D. G.

    2016-05-01

    We demonstrate efficient generation of terahertz (THz) frequency radiation by pulsed excitation, at wavelengths between 800 and 1550 nm, of photoconductive (PC) switches fabricated using Fe-doped InGaAsP wafers, grown by metal organic chemical vapor deposition (MOCVD). Compared to our previous studies of Fe-doped InGaAs wafers, Fe:InGaAsP wafers exhibited five times greater dark resistivity to give a value of 10 kΩ cm, and Fe:InGaAsP PC switches produced five times higher THz power emission. The effect of Fe-doping concentration (between 1E16 and 1.5E17 cm-3) on optical light absorption (between 800 and 1600 nm), on resistivity, and on THz emission is also discussed.

  9. Generation of continuous wave terahertz frequency radiation from metal-organic chemical vapour deposition grown Fe-doped InGaAs and InGaAsP

    NASA Astrophysics Data System (ADS)

    Mohandas, Reshma A.; Freeman, Joshua R.; Rosamond, Mark C.; Hatem, Osama; Chowdhury, Siddhant; Ponnampalam, Lalitha; Fice, Martyn; Seeds, Alwyn J.; Cannard, Paul J.; Robertson, Michael J.; Moodie, David G.; Cunningham, John E.; Davies, A. Giles; Linfield, Edmund H.; Dean, Paul

    2016-04-01

    We demonstrate the generation of continuous wave terahertz (THz) frequency radiation from photomixers fabricated on both Fe-doped InGaAs and Fe-doped InGaAsP, grown by metal-organic chemical vapor deposition. The photomixers were excited using a pair of distributed Bragg reflector lasers with emission around 1550 nm, and THz radiation was emitted over a bandwidth of greater than 2.4 THz. Two InGaAs and four InGaAsP wafers with different Fe doping concentrations were investigated, with the InGaAs material found to outperform the InGaAsP in terms of emitted THz power. The dependencies of the emitted power on the photomixer applied bias, incident laser power, and material doping level were also studied.

  10. Evolution of structural and optical properties of photocatalytic Fe doped TiO{sub 2} thin films prepared by RF magnetron sputtering

    SciTech Connect

    Nair, Prabitha B. Maneeshya, L. V. Justinvictor, V. B. Daniel, Georgi P. Joy, K. Thomas, P. V.

    2014-01-28

    Undoped and Fe doped TiO{sub 2} thin films have been prepared by RF magnetron sputtering. Pure TiO{sub 2} thin film exhibited an amorphous-like nature. With increase in iron concentration (0–0.1 at%), the films exhibited better crystallization to anatase phase . Red shift of absorption edge was observed in the UV-vis transmittance spectra . At higher Fe concentration (0.5 at%), onset of phase transformation to rutile is noticed. Photocatalytic properties of pure and 0.1 at% Fe doped TiO{sub 2} thin films were investigated by degradation of methylene blue in UV light, visible light and light from Hg vapor lamp. 70% degradation of methylene blue was observed in the presence of Fe doped film in comparison with 3% degradation in presence of pure TiO{sub 2} film when irradiated using visible light for 2 h.

  11. Local structure of Fe in Fe-doped misfit-layered calcium cobaltite: An X-ray absorption spectroscopy study

    SciTech Connect

    Prasoetsopha, Natkrita; Pinitsoontorn, Supree; Bootchanont, Atipong; Kidkhunthod, Pinit; Srepusharawoot, Pornjuk; Kamwanna, Teerasak; Amornkitbamrung, Vittaya; Kurosaki, Ken; Yamanaka, Shinsuke

    2013-08-15

    Polycrystalline Ca{sub 3}Co{sub 4−x}Fe{sub x}O{sub 9+δ} ceramics (x=0, 0.01, 0.03, 0.05) were fabricated using a simple thermal hydro-decomposition method and a spark plasma sintering technique. Thermoelectric property measurements showed that increasing Fe concentration resulted in a decrease in electrical resistivity, thermopower and thermal conductivity, leading to an improvement in the dimensionless figure-of-merit, >35% for x=0.05 at 1073 K. An X-ray absorption spectroscopy technique was used to investigate the local structure of Fe ions in the Ca{sub 3}Co{sub 4−x}Fe{sub x}O{sub 9+δ} structure for the first time. By fitting data from the extended X-ray absorption fine structure (EXAFS) spectra and analyzing the X-ray absorption near-edge structure (XANES) spectra incorporated with first principle simulation, it was shown that Fe was substituted for Co in the the Ca{sub 2}CoO{sub 3} (rocksalt, RS) layer rather than in the CoO{sub 2} layer. Variation in the thermoelectric properties as a function of Fe concentration was attributed to charge transfer between the CoO{sub 2} and the RS layers. The origin of the preferential Fe substitution site was investigated considering the ionic radii of Co and Fe and the total energy of the system. - Graphical abstract: The Fe K-edge XANES spectra of: (a) experimental result in comparison to the simulated spectra when Fe atoms were substituted in the RS layer; (b) with magnetic moment; (c) without magnetic moment, and in the CoO{sub 2} layer; (d) with magnetic moment and (e) without magnetic moment. Highlights: • Synthesis, structural studies, and thermoelectric properties of Ca{sub 3}Co{sub 4−x}Fe{sub x}O{sub 9+δ}. • Direct evidence for the local structure of the Fe ions in the Ca{sub 3}Co{sub 4−x}Fe{sub x}O{sub 9+δ} using XAS analysis. • EXAFS and XANES analysis showed that Fe was likely to be situated in the RS layer structure. • Changes in TE property with Fe content was due to charge transfer between the CoO{sub 2} and the RS layers. • Total energy calculation showed energetically favorable Fe substitution in the RS layer.

  12. Fe-doped nanostructured titanates synthesized in a single step route

    SciTech Connect

    Costa, A.M.L.M.; Marinkovic, B.A.; Suguihiro, N.M.; Smith, D.J.; Costa, M.E.H.M. da; Paciornik, S.

    2015-01-15

    for the synthesis of nanotitanates. • Fe-doped nanotitanates have been prepared in a single step wet chemistry route. • The morphology of the nanometric titanates is a function of the temperature. • Mössbauer spectroscopy reveals Fe{sup 3} {sup +} in octahedral sites inside nanosheets. • The Fe incorporation in nanosheets improved the visible light absorption.

  13. Characteristics and anticorrosion performance of Fe-doped TiO2 films by liquid phase deposition method

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Xu, Chao; Feng, ZuDe

    2014-09-01

    Fe-doped TiO2 thin films were fabricated by liquid phase deposition (LPD) method, using Fe(III) nitrate as both Fe element source and fluoride scavenger instead of commonly-used boric acid (H3BO3). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis spectrum were employed to examine the effects of Fe element on morphology, structure and optical characteristics of TiO2 films. The as-prepared films were served as photoanode applied to photogenerated cathodic protection of SUS304 stainless steel (304SS). It was observed that the photoelectrochemical properties of the as-prepared films were enhanced with the addition of Fe element compared to the undoped TiO2 film. The highest photoactivity was achieved for Ti13Fe (Fe/Ti = 3 molar ratio) film prepared in precursor bath containing 0.02 M TiF4 + 0.06 M Fe(NO3)3 under white-light illumination. The effective anticorrosion behaviors can be attributed to the Fe element incorporation which decreases the probability of photogenerated charge-carrier recombination and extends the light response range of Fe-doped TiO2 films appeared to visible-light region.

  14. Effect of Al and Fe doping in ZnO on magnetic and magneto-transport properties

    NASA Astrophysics Data System (ADS)

    Kumar, Santosh; Deepika; Tripathi, Malvika; Vaibhav, Pratyush; Kumar, Aman; Kumar, Ritesh; Choudhary, R. J.; Phase, D. M.

    2016-12-01

    The structural, magnetic and magneto-transport of undoped ZnO, Zn0.97Al0.03O, Zn0.95Fe0.05O and Zn0.92Al0.03Fe0.05O thin films grown on Si(100) substrate using pulsed laser deposition were investigated. The single phase nature of the films is confirmed by X-ray diffraction and Raman spectroscopy measurements. The possibility of Fe metal cluster in Fe doped/co-doped films is ruled out by Fe 2p core level photoelectron spectra. From O 1s core level spectra it is observed that oxygen vacancy is present in all the films. The undoped ZnO film shows magnetic ordering below ∼175 K, whereas Fe doped/codoped samples show magnetic ordering even at 300 K. The Al doped sample reveals paramagnetic behavior. The magneto-transport measurements suggest that the mobile carriers undergo exchange interaction with local magnetic moments.

  15. Fe-doped SnO2 nanoparticles as new high capacity anode material for secondary lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Mueller, Franziska; Bresser, Dominic; Chakravadhanula, Venkata Sai Kiran; Passerini, Stefano

    2015-12-01

    Herein, Fe-doped tin oxide is presented for the first time as new high-capacity lithium-ion anode material. Pure SnO2, Fe-doped SnO2 (Sn0.9Fe0.1O2, SFO), and carbon-coated SFO (SFO-C) were synthesized and morphologically and electrochemically characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, Brunauer-Emmet-Teller method, and galvanostatic (dis-)charge measurements. Doping SnO2 with Fe results in a substantially enhanced reversible specific capacity and coulombic efficiency. After ten cycles the reversible capacity of SFO-C was about 1519 mAh g-1, i.e., almost twice the specific capacity obtained for pure SnO2 (764 mAh g-1). Moreover, limiting the reversible capacity to 600 mAh g-1 shows the great potential of SFO-C for application in lithium-ion batteries.

  16. Observation of stimulated emission from a single Fe-doped AlN triangular fiber at room temperature

    NASA Astrophysics Data System (ADS)

    Jiang, Liangbao; Jin, Shifeng; Wang, Wenjun; Zuo, Sibin; Li, Zhilin; Wang, Shunchong; Zhu, Kaixing; Wei, Zhiyi; Chen, Xiaolong

    2015-12-01

    Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20-50 μm and a length of 0.5-1 mm were preparated successfully. Stimulated emission (peak at about 607 nm and FWHM ~0.2 nm) and a long luminescence lifetime (2.5 ms) were observed in the fibers by a 532nm laser excitation at room temperature. The high quality long AlN fibers are also found to be good optical waveguides. This kind of fiber lasers may possess potential advantages over traditional fiber lasers in enhancing power output and extending laser wavelengths from infrared to visible regime.

  17. Observation of stimulated emission from a single Fe-doped AlN triangular fiber at room temperature.

    PubMed

    Jiang, Liangbao; Jin, Shifeng; Wang, Wenjun; Zuo, Sibin; Li, Zhilin; Wang, Shunchong; Zhu, Kaixing; Wei, Zhiyi; Chen, Xiaolong

    2015-01-01

    Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20-50 μm and a length of 0.5-1 mm were preparated successfully. Stimulated emission (peak at about 607 nm and FWHM ~0.2 nm) and a long luminescence lifetime (2.5 ms) were observed in the fibers by a 532 nm laser excitation at room temperature. The high quality long AlN fibers are also found to be good optical waveguides. This kind of fiber lasers may possess potential advantages over traditional fiber lasers in enhancing power output and extending laser wavelengths from infrared to visible regime. PMID:26647969

  18. Observation of stimulated emission from a single Fe-doped AlN triangular fiber at room temperature

    PubMed Central

    Jiang, Liangbao; Jin, Shifeng; Wang, Wenjun; Zuo, Sibin; Li, Zhilin; Wang, Shunchong; Zhu, Kaixing; Wei, Zhiyi; Chen, Xiaolong

    2015-01-01

    Aluminum nitride (AlN) is a well known wide-band gap semiconductor that has been widely used in fabricating various ultraviolet photo-electronic devices. Herein, we demonstrate that a fiber laser can be achieved in Fe-doped AlN fiber where Fe is the active ion and AlN fiber is used as the gain medium. Fe-doped single crystal AlN fibers with a diameter of 20–50 μm and a length of 0.5–1 mm were preparated successfully. Stimulated emission (peak at about 607 nm and FWHM ~0.2 nm) and a long luminescence lifetime (2.5 ms) were observed in the fibers by a 532nm laser excitation at room temperature. The high quality long AlN fibers are also found to be good optical waveguides. This kind of fiber lasers may possess potential advantages over traditional fiber lasers in enhancing power output and extending laser wavelengths from infrared to visible regime. PMID:26647969

  19. Modulation of Calcium Signaling of Angiotensin AT1, Endothelin ETA, and ETB Receptors by Silibinin, Quercetin, Crocin, Diallyl Sulfides, and Ginsenoside Rb1.

    PubMed

    Bahem, Ruba; Hoffmann, Anja; Azonpi, Arnaud; Caballero-George, Catherina; Vanderheyden, Patrick

    2015-06-01

    Angiotensin II and endothelin-1 are potent vasoconstrictive peptides that play a central role in blood pressure regulation. Both peptides exert their pleiotropic effects via binding to their respective G-protein-coupled receptors, i.e., angiotensin AT1 and endothelin type A and type B receptors. In the present study, we have selected six structurally different plant-derived compounds with known cardioprotective properties to evaluate their ability to modulate calcium signaling of the above-mentioned receptors. For this purpose, we used and validated a cellular luminescence-based read-out system in which we measured intracellular calcium signaling in Chinese hamster ovary cells that express the calcium sensitive apo-aequorin protein. Firstly, silibinin, a flavanolignan that occurs in milk thistle (Silybum marianum), was investigated and found to be an antagonist for the human angiotensin AT1 receptor with an affinity constant of about 9 µM, while it had no effect on endothelin type A or type B receptor activation. Quercetin and crocin partially impeded intracellular calcium signaling resulting in a non-receptor-related reduction of the responses recorded for the three investigated G-protein-coupled receptors. Two organosulfur compounds, diallyl disulfide and diallyl trisulfide, as well as the triterpene saponin ginsenoside Rb1 did not affect the activation of the angiotensin AT1 and endothelin type A and type B receptors. In conclusion, we were able, by using a nonradioactive cellular read-out system, to identify a novel pharmacological property of the flavanolignan silibinin. PMID:25519917

  20. Selenium sulfide

    Integrated Risk Information System (IRIS)

    Selenium sulfide ; CASRN 7446 - 34 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  1. Hydrogen sulfide

    Integrated Risk Information System (IRIS)

    Hydrogen sulfide ; 7783 - 06 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  2. Carbonyl sulfide

    Integrated Risk Information System (IRIS)

    Carbonyl sulfide ; CASRN 463 - 58 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  3. Influence of Fe-doping on the structural, optical, and magnetic properties of ZnO thin films prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Goktas, A.; Mutlu, I. H.; Yamada, Y.

    2013-05-01

    Zn1-xFexO thin films with different Fe (0 ⩽ x ⩽ 0.20) content were produced by sol-gel dip coating method. The influence of Fe doping on the structural, optical and magnetic properties of ZnO thin films was investigated. X-ray diffraction has shown that the films are polycrystalline and textured with c-axis of the hexagonal structure along the growth direction. Scanning electron microscope has indicated that the surface of the films is homogeneous with no cracking and the grain sizes tend to decrease with the increase of Fe-doping concentration. Ultraviolet-visible measurements show a reduction in band gap of the films with increase in Fe content from 3.27 eV to 3.10 eV. The magnetic measurements performed at 5, 100, 200 and 300 K using a SQUID magnetometer revealed the dominant paramagnetic behavior until Fe doping ratio of 10% and clear magnetic hysteresis loops at 5 and 100 K for the highest Fe doping ratio of 20%. The observed ferromagnetic behavior is likely related to a partial incorporation of Zn into the Fe3O4, i.e. Fe3-xZnxO4 composition or disorders as well as some defects.

  4. Preparation and photoelectric properties of Fe-doped mesoporous TiO2 thick films used in DSSC

    NASA Astrophysics Data System (ADS)

    Xie, Yian; Shen, Yue; Gu, Feng; Lu, Huina; Wu, Mingming; Wang, Linjun

    2009-08-01

    Fe-doped mesoporous TiO2 (M-TiO2-Fe) thick films were prepared by sol-gel and screen printing process. Raman characteristics results show that the M-TiO2-Fe thick film possesses a certain degree of the anatase phase, which may have advantages on photocatalysis and photovoltaic ability. Derived from small angel X-Ray diffraction (SAXRD), the films exhibit mesoporous structure with pore size around 7-8 nm. Eg of the films was obviously narrowed from 3.4 eV to 3.0 eV, which allows the thick films using more light to initiate photovoltaic process. Dye-sensitized solar cell (DSSC) based on M-TiO2-Fe was structured and chlorophyl was used as sensitizers. The solar cells have an open circuit voltage above 260mV.

  5. Fe solubility, growth mechanism, and luminescence of Fe doped ZnO nanowires and nanorods grown by evaporation-deposition

    NASA Astrophysics Data System (ADS)

    Alemán, Belén; Ortega, Yanicet; García, José Ángel; Fernández, Paloma; Piqueras, Javier

    2011-07-01

    Fe doped ZnO nanowires, nanorods, and urchin-like nanostructures have been grown using an evaporation-deposition method with compacted mixtures of ZnS and Fe2O3 powders, with different Fe contents as precursors. Treatments at 950 °C under argon flow lead to the growth of iron doped nanowires, nanorods, and other nanostructures on the surface of the compacted sample. The incorporation of iron into the nanostructures has been investigated via energy dispersive spectroscopy as well as by cathodoluminescence in a scanning electron microscope and photoluminescence in an optical microscope. The iron content in the structures is limited to the range of 0.5-0.7 at.% and does not depend on the content in the precursor. Bright and dark field imaging and twist contour analysis via transmission electron microscopy support the possibility of a dislocation driven growth of the nanowires.

  6. Optical and structural properties of Fe-doped SnO2 nanoparticles prepared by co-precipitation method

    NASA Astrophysics Data System (ADS)

    Kaur, Navneet; Abhinav, Singh, Gurwinder Pal; Singh, Vishal; Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    Today nanomaterials plays important role in every field, due to their unique mechanical, chemical and electrical properties which are completely different from the bulk materials. With reduction in the size of material its properties are dynamically changed. Semiconductor materials are widely used in electronic devices but in the field of optoelectronic these materials have some limitations. Tin oxide could be the material which could be used in these applications without limitations. Doped Tin Oxide is an oxygen deficient material which could be beneficial for transparent conducting oxide. Iron doped SnO2 prepared by co-precipitation method. Studies on structural properties of undoped and doped SnO2 were done by X-ray diffraction. The XRD results have shown that the size of the nanoparticles decreases with Fe doping down to 53nm. Optical Properties were studied by UV-visible spectroscopy. Band gap was found to decrease with increase in iron content in samples.

  7. Highly-active oxygen evolution electrocatalyzed by a Fe-doped NiSe nanoflake array electrode.

    PubMed

    Tang, Chun; Asiri, Abdullah M; Sun, Xuping

    2016-03-25

    Alkaline water electrolysis offers a simple method for mass production of hydrogen but suffers from the sluggish kinetics of the anodic oxygen evolution reaction (OER), calling for the development of low-cost and durable oxygen evolution electrocatalysts with high activity. In this communication, we report a highly-active robust oxygen evolution electrode, developed by in situ hydrothermal growth of an Fe-doped NiSe nanoflake array directly on a macroporous FeNi foam (Fe-NiSe/FeNi foam). This electrode catalyzes the OER with an onset overpotential as low as 200 mV and needs overpotentials of 245 and 264 mV to achieve 50 and 100 mA cm(-2), respectively, in 1.0 M KOH. Remarkably, it is also highly robust to drive 500 and 1000 mA cm(-2) at overpotentials of 246 and 263 mV, respectively, in 30 wt% KOH. PMID:26935420

  8. TREATMENT OF METAL FINISHING WASTES BY SULFIDE PRECIPITATION

    EPA Science Inventory

    This project involved precipitating heavy metals normally present in metal finishing wastewaters by a novel process which employs ferrous sulfide addition (Sulfex), as well as by conventional treatment using calcium hydroxide for comparison purposes. These studies consisted of la...

  9. Endogenous and exogenous hydrogen sulfide facilitates T-type calcium channel currents in Cav3.2-expressing HEK293 cells.

    PubMed

    Sekiguchi, Fumiko; Miyamoto, Yosuke; Kanaoka, Daiki; Ide, Hiroki; Yoshida, Shigeru; Ohkubo, Tsuyako; Kawabata, Atsufumi

    2014-02-28

    Hydrogen sulfide (H2S), a gasotransmitter, is formed from l-cysteine by multiple enzymes including cystathionine-γ-lyase (CSE). We have shown that an H2S donor, NaHS, causes hyperalgesia in rodents, an effect inhibited by knockdown of Cav3.2 T-type Ca(2+) channels (T-channels), and that NaHS facilitates T-channel-dependent currents (T-currents) in NG108-15 cells that naturally express Cav3.2. In the present study, we asked if endogenous and exogenous H2S participates in regulation of the channel functions in Cav3.2-transfected HEK293 (Cav3.2-HEK293) cells. dl-Propargylglycine (PPG), a CSE inhibitor, significantly decreased T-currents in Cav3.2-HEK293 cells, but not in NG108-15 cells. NaHS at 1.5mM did not affect T-currents in Cav3.2-HEK293 cells, but enhanced T-currents in NG108-15 cells. In the presence of PPG, NaHS at 1.5mM, but not 0.1-0.3mM, increased T-currents in Cav3.2-HEK293 cells. Similarly, Na2S, another H2S donor, at 0.1-0.3mM significantly increased T-currents in the presence, but not absence, of PPG in Cav3.2-HEK293 cells. Expression of CSE was detected at protein and mRNA levels in HEK293 cells. Intraplantar administration of Na2S, like NaHS, caused mechanical hyperalgesia, an effect blocked by NNC 55-0396, a T-channel inhibitor. The in vivo potency of Na2S was higher than NaHS. These results suggest that the function of Cav3.2 T-channels is tonically enhanced by endogenous H2S synthesized by CSE in Cav3.2-HEK293 cells, and that exogenous H2S is capable of enhancing Cav3.2 function when endogenous H2S production by CSE is inhibited. In addition, Na2S is considered a more potent H2S donor than NaHS in vitro as well as in vivo. PMID:24508802

  10. Comparison of the low-temperature specific heat of Fe- and Co-doped Bi{sub 1.8}Pb{sub 0.2}Sr{sub 2}Ca(Cu{sub 1{minus}{ital x}}{ital M}{sub {ital x}}){sub 2}O{sub 8} ({ital M}=Fe or Co): Anomolously enhanced electronic contribution due to Fe doping

    SciTech Connect

    Yu, M.K.; Franck, J.P.

    1996-04-01

    Specific-heat data of Fe-doped Bi{sub 1.8}Pb{sub 0.2}Sr{sub 2}Ca(Cu{sub 1{minus}{ital x}}Fe{sub {ital x}}){sub 2}O{sub 8} in the range 2{endash}20 K are presented for {ital x}=1, 2, 4, 6, and 8{percent}. The data are compared with our previous measurements on Co-doped bismuth-strontium-calcium-copper oxide superconductors of nominal composition Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (BISCO 2212). Both Fe and Co are magnetic substitutions with effective moments close to their free-ion value. In the normal state the magnetic susceptibility increases by more than a factor 2 over the doping range due to effective-mass enhancement. In the superconducting state both ions act as magnetic pair breakers. For Co doping the normal-state linear term {gamma} is observed, enhanced due to the effective-mass increase. For Fe doping we observe a large anomalous contribution to the electronic specific heat starting near 15 K and leading at the lowest temperature to a linear term near {gamma}{sub 0}=72 mJ/moleK{sup 2} (1 mole=1 formula unit). The anomalous term is typical of heavy fermion behavior. Comparison with specific-heat data of Co-doped BISCO 2212 suggests that hybridization between 3{ital d} electrons of the dopant and the planar carriers is more effective for Fe doping than for Co doping. {copyright} {ital 1996 The American Physical Society.}

  11. Exploring a new phenomenon in the bactericidal response of TiO2 thin films by Fe doping: Exerting the antimicrobial activity even after stoppage of illumination

    NASA Astrophysics Data System (ADS)

    Naghibi, Sanaz; Vahed, Shohreh; Torabi, Omid; Jamshidi, Amin; Golabgir, Mohammad Hossein

    2015-02-01

    Antibacterial properties of Fe-doped TiO2 thin films prepared on glass by the sol-gel hot-dipping technique were studied. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, scanning probe microscopy and X-ray photoelectron spectroscopy. The photocatalytic activities were evaluated by measuring the decomposition rate of methylene blue under ultra violet and visible light. The antibacterial properties of the coatings were investigated against Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisia and Aspergillus niger. The principle of incubation methods was also discussed. The results indicated that Fe doping of thin films eventuated in high antibacterial properties under visible light and this performance remained even after stoppage of illumination. This article tries to provide some explanation for this fact.

  12. Half-metallic ferromagnetism in Fe-doped Zn{sub 3}P{sub 2} from first-principles calculations

    SciTech Connect

    Jaiganesh, G. Jaya, S. Mathi

    2014-04-24

    Using the first-principles calculations based on the density functional theory, we have studied the magnetism and electronic structure of Fe-doped Zinc Phosphide (Zn{sub 3}P{sub 2}). Our results show that the half-metallic ground state and ferromagnetic stability for the small Fe concentrations considered in our study. The stability of the doped material has been studied by calculating the heat of formation and analyzing the minimum total energies in nonmagnetic and ferromagnetic phases. A large value of the magnetic moment is obtained from our calculations and our calculation suggests that the Fe-doped Zn{sub 3}P{sub 2} may be a useful material in semiconductor spintronics.

  13. Structure and magnetic properties of Fe doped In{sub 2}O{sub 3} thin films prepared by electron beam evaporation

    SciTech Connect

    Krishna, N. Sai; Kaleemulla, S. Rao, N. Madhusudhana; Krishnamoorthi, C.; Begam, M. Rigana; Amarendra, G.

    2015-06-24

    Pure and Fe (7 at.%) doped In{sub 2}O{sub 3} thin films were grown onto the glass substrates by electron beam evaporation technique. The structural and magnetic properties of the pure and Fe doped In{sub 2}O{sub 3} thin films have been studied. The undoped and Fe doped In{sub 2}O{sub 3} thin films shown ferromagnetic property at room temperature. A magnetization of 24 emu/cm{sup 3} was observed for pure In{sub 2}O{sub 3} thin films. The magnetization of 38.23 emu/cm{sup 3} was observed for the Fe (7 at.%) doped In{sub 2}O{sub 3} thin films.

  14. Crossover between two-dimensional surface state and three-dimensional bulk phase in Fe-doped Bi2Te3

    NASA Astrophysics Data System (ADS)

    Jo, Na Hyun; Lee, Kyujoon; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee; Jung, Myung-Hwa

    2014-06-01

    In Fe-doped Bi2Te3, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi2Te3.

  15. Crossover between two-dimensional surface state and three-dimensional bulk phase in Fe-doped Bi{sub 2}Te{sub 3}

    SciTech Connect

    Jo, Na Hyun; Lee, Kyujoon; Jung, Myung-Hwa; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee

    2014-06-23

    In Fe-doped Bi{sub 2}Te{sub 3}, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi{sub 2}Te{sub 3}.

  16. Interlinked multiphase Fe-doped MnO2 nanostructures: a novel design for enhanced pseudocapacitive performance

    NASA Astrophysics Data System (ADS)

    Wang, Ziya; Wang, Fengping; Li, Yan; Hu, Jianlin; Lu, Yanzhen; Xu, Mei

    2016-03-01

    Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g-1 even under a high mass loading (~5 mg cm-2). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm-3) and excellent cycling stability of 100% capacitance retention after 2000 cycles at 2 A g-1. The synergistic effects of alternative crystal structures, appropriate crystallinity and optimal morphology are identified to be responsible for the observations. This rational multiphase composite strategy provides a promising idea for materials scientists to design and prepare scalable electrode materials for energy storage devices.Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g-1 even under a high mass loading (~5 mg cm-2). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm-3) and

  17. Fabrication of Fe-doped TiO2 nanoparticles and investigation of photocatalytic decolorization of reactive red 198 under visible light irradiation.

    PubMed

    Moradi, Halimeh; Eshaghi, Akbar; Hosseini, Seyed Rahman; Ghani, Kamal

    2016-09-01

    In this research, Fe-doped TiO2 nanoparticles with various Fe concentrations (0. 0.1, 1, 5 and 10wt%) were prepared by a sol-gel method. Then, nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis (EDX), BET surface area, photoluminescence (PL) spectroscopy and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the nano-particles was evaluated through degradation of reactive red 198 (RR 198) under UV and visible light irradiations. XRD results revealed that all samples contained only anatase phase. DRS showed that the Fe doping in the titania induced a significant red shift of the absorption edge and then the band gap energy decreased from 3 to 2.1eV. Photocatalytic results indicated that TiO2 had a highest photocatalytic decolorization of the RR 198 under UV irradiation whereas photocatalytic decolorization of the RR 198 under visible irradiation increased in the presence of Fe-doped TiO2 nanoparticles. Among the samples, Fe-1wt% doped TiO2 nanoparticles showed the highest photocatalytic decolorization of RR198 under visible light irradiation. PMID:27150776

  18. Sulfide chemiluminescence detection

    DOEpatents

    Spurlin, Stanford R.; Yeung, Edward S.

    1985-01-01

    A method of chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction.

  19. Sulfide chemiluminescence detection

    DOEpatents

    Spurlin, S.R.; Yeung, E.S.

    1985-11-26

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  20. Interlinked multiphase Fe-doped MnO2 nanostructures: a novel design for enhanced pseudocapacitive performance.

    PubMed

    Wang, Ziya; Wang, Fengping; Li, Yan; Hu, Jianlin; Lu, Yanzhen; Xu, Mei

    2016-03-24

    Structure designing and morphology control can lead to high performance pseudocapacitive materials for supercapacitors. In this work, we have designed interlinked multiphase Fe-doped MnO2 nanostructures (α-MnO2/R-MnO2/ε-MnO2) to enhance the electrochemical properties by a facile method. These hierarchical hollow microspheres assembled by interconnected nanoflakes, and with plenty of porous nanorods radiating from the spherical shells were hydrothermally obtained. The supercapacitor electrode prepared from the unique construction exhibits outstanding specific capacitance of 267.0 F g(-1) even under a high mass loading (∼5 mg cm(-2)). Obviously improved performances compared to pure MnO2 are also demonstrated with a good rate capability, high energy density (1.30 mW h cm(-3)) and excellent cycling stability of 100% capacitance retention after 2000 cycles at 2 A g(-1). The synergistic effects of alternative crystal structures, appropriate crystallinity and optimal morphology are identified to be responsible for the observations. This rational multiphase composite strategy provides a promising idea for materials scientists to design and prepare scalable electrode materials for energy storage devices. PMID:26977698

  1. Fabrication of a 3D active mixer based on deformable Fe-doped PDMS cones with magnetic actuation

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza; Alizadeh, Elaheh

    2012-11-01

    In this paper an active 3D mixer for lab-on-chip applications is presented. The micrometer size cone shape holes are ablated on a PMMA sheet utilizing a CO2 laser. The holes are filled with Fe micro-particles and the whole structure is molded with PDMS which cause the Fe micro-particles to be trapped in a PDMS cone structure. These Fe-doped PDMS cones are placed in a PMMA micro-channel structure fabricated by CO2 laser machining. By applying an external periodic magnetic field, the cones periodically bend in the micro-channel and stir the fluid. The fabrication method and the effect of the magnetic field on the bending of the cones with different aspect ratios is also discussed utilizing computer simulation. Doping the polymers with micro- and nano-metallic particles has been carried out by different research groups before, but according to our knowledge, application of such structures for the fabrication of a 3D active mixer has not been presented before.

  2. Electrochemical reactions and cathode properties of Fe-doped Li2O for the hermetically sealed lithium peroxide battery

    NASA Astrophysics Data System (ADS)

    Harada, Kosuke; Hibino, Mitsuhiro; Kobayashi, Hiroaki; Ogasawara, Yoshiyuki; Okuoka, Shin-ichi; Yonehara, Koji; Ono, Hironobu; Sumida, Yasutaka; Yamaguchi, Kazuya; Kudo, Tetsuichi; Mizuno, Noritaka

    2016-08-01

    Fe-doped Li2O (FDL) is synthesized mechanochemically and is demonstrated as a new Co-free cathode material for use in sealed Li2O2 batteries, which have been proposed as high energy density batteries. Fe3+ ions are substitutionally doped into the Li sites in an antifluorite-type Li2O structure to create FDL. The FDL consists of (Li0.82Fe0.06)2O (d-FDL) and high-temperature form of Li5FeO4 (o-FDL), in which Fe3+ ions disorderly and orderly arranged, respectively. According to the Mössbauer spectra and quantitative peroxide species analysis, the FDL cathode operates principally based on the redox reaction between O22- and O2-. X-ray diffraction study reveals that the reversible formation of O22- proceeds mainly in the d-FDL. An irreversible side reaction involving the evolution of oxygen gas occurs when the cathode is charged to more than 250 mAh g-1. The FDL (Fe/(Li + Fe) = 10 at%) cathode exhibits a reversible capacity of 200 mAh g-1 over 200 cycles at a current density of 22.5 mA g-1.

  3. Structural transitions, magnetic properties, and electronic structures of Co(Fe)-doped MnNiSi compounds

    SciTech Connect

    Li, Y.; Wei, Z. Y.; Liu, E. K. Wang, S. G.; Wang, W. H.; Wu, G. H.; Liu, G. D.

    2015-05-07

    The structural transitions, magnetic properties, and electronic structures of Co(Fe)-doped MnNiSi compounds are investigated by x-ray powder diffraction, differential scanning calorimetry (DSC), magnetic measurements, and first-principles calculations. Results indicate that all samples undergo a martensitic transition from the Ni{sub 2}In-type parent phase to TiNiSi-type orthorhombic phase at high temperatures. The substitution of Co(Fe) for Mn in Mn{sub 1−x}Co{sub x}NiSi (x = 0.2, 0.3, and 0.4) and Mn{sub 1−y}Fe{sub y}NiSi (y = 0.26, 0.30, 0.36, 0.46, and 0.55) samples decreases the structural transition temperature and Curie temperature of martensite. The martensite phases show a typical ferromagnetic behavior with saturation field being basically unchanged with increasing Co(Fe) content, while the saturation magnetization shows a decreasing tendency. The theoretically calculated moments are in good agreement with the experimentally measured results. The orbital hybridizations between different 3d elements are analyzed from the distribution of density of states.

  4. FP-LAPW investigation of electronic, magnetic, elastic and thermal properties of Fe-doped zirconium nitride

    SciTech Connect

    Sirajuddeen, M. Mohamed Sheik Banu, I. B. Shameem

    2014-05-15

    Full Potential- Linear Augmented Plane Wave (FP-LAPW) method has been employed to study the electronic, magnetic, elastic and thermal properties of Fe-doped Zirconium nitride. In this work, Fe-atoms were doped into the super cell of ZrN in doping concentrations of 12.5%, 25% and 37.5% to replace Zr atoms. Electronic properties such as band structure and DOS were plotted and compared for the doped compounds. Charge density contours were plotted for all the doped compounds. The non-magnetic ZrN doped in different Fe concentrations were found to be ferromagnetic. Magnetic moments have been calculated and compared. Elastic properties have been studied and compared with electronic properties. Appearance of magnetic ordering and its influence with the elastic properties have been reported. Impact of 3d states of Fe in DOS plot on the elastic nature of the compounds has been highlighted. Thermal properties such as Debye temperature and molar heat capacities at low temperature have been determined. Debye temperature is found to decrease with higher doping concentrations. Molar heat capacities are found to increase with higher concentrations of Fe atoms.

  5. Calcium alloy as active material in secondary electrochemical cell

    DOEpatents

    Roche, Michael F.; Preto, Sandra K.; Martin, Allan E.

    1976-01-01

    Calcium alloys such as calcium-aluminum and calcium-silicon, are employed as active material within a rechargeable negative electrode of an electrochemical cell. Such cells can use a molten salt electrolyte including calcium ions and a positive electrode having sulfur, sulfides, or oxides as active material. The calcium alloy is selected to prevent formation of molten calcium alloys resulting from reaction with the selected molten electrolytic salt at the cell operating temperatures.

  6. Role of epitaxial strain on the magnetic structure of Fe-doped CoFe2O4

    NASA Astrophysics Data System (ADS)

    Moyer, J. A.; Kumah, D. P.; Vaz, C. A. F.; Arena, D. A.; Henrich, V. E.

    2013-11-01

    The magnetic structure of Fe-doped CoFe2O4 (Co1-xFe2+xO4) grown on MgO (0 0 1) and SrTiO3 (0 0 1) substrates is studied with superconducting quantum interference device magnetometry and soft x-ray magnetic spectroscopies. X-ray and electron diffraction show that the choice of substrate has large effects on the strain, crystal structure and surface morphology of Co1-xFe2+xO4 thin films. Samples grown on MgO have small, coherent strains and surfaces that are nearly atomically flat, whereas films grown on SrTiO3 have large tensile strains and surfaces terminated with islands, which indicate the presence of a large density of misfit dislocations. These differences in structural properties correlate with the large differences seen in the magnetic structure; samples grown on SrTiO3 have larger magnetic moments and increased anisotropies compared to those grown on MgO. Most strikingly, the large magnetic spin and orbital moments found in the films grown on SrTiO3 suggest a suppression of anti-phase boundary formation, which we attribute to the large compressive lattice mismatch and the formation of misfit dislocations during the film growth in order to relieve the epitaxial strain. This results in the films grown on SrTiO3 having magnetic properties that are more similar to bulk Co1-xFe2+xO4 than those grown on MgO, demonstrating that epitaxial strain can result in large changes in the magnetic structure of Co1-xFe2+xO4.

  7. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1992-07-07

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  8. Cadmium sulfide membranes

    DOEpatents

    Spanhel, Lubomir; Anderson, Marc A.

    1991-10-22

    A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

  9. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  10. Morphology-controlled synthesis and novel microwave electromagnetic properties of hollow urchin-like chain Fe-doped MnO{sub 2} under 10 T high magnetic field

    SciTech Connect

    Yuping, Duan; Jia, Zhang; Hui, Jing; Shunhua, Liu

    2011-05-15

    Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized under a high magnetic field of 10 T. The formation mechanism was investigated and discussed in detail. The synthesized samples were characterized by XRD, SEM, TEM, EMPA, and vector network analysis. By doping MnO{sub 2} with Fe, the relative complex permittivity of MnO{sub 2} and its corresponding loss tangent clearly decreases, but its relative complex permeability and its corresponding loss tangent markedly increases. Moreover, the theoretically calculated values of reflection loss show that with increasing the Fe content, the as-prepared Fe-doped MnO{sub 2} exhibits good microwave absorption capability. -- Graphical Abstract: Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized in a high magnetic field of 10 T via a simple chemical process. Display Omitted Highlights: {yields} Fe-doped MnO{sub 2} with a hollow sea urchin-like ball chain shape was first synthesized. {yields} We investigated formation mechanism and electromagnetic properties of the Fe-doped MnO{sub 2}. {yields} By doping MnO{sub 2} with Fe, the electromagnetic properties are improved obviously.

  11. Ultrathin graphitic carbon nitride nanosheets: a novel peroxidase mimetic, Fe doping-mediated catalytic performance enhancement and application to rapid, highly sensitive optical detection of glucose.

    PubMed

    Tian, Jingqi; Liu, Qian; Asiri, Abdullah M; Qusti, Abdullah H; Al-Youbi, Abdulrahman O; Sun, Xuping

    2013-12-01

    In this article, we demonstrate for the first time that ultrathin graphitic carbon nitride nanosheets (g-C3N4) possess peroxidase activity. Fe doping of the nanosheets leads to peroxidase mimetics with greatly enhanced catalytic performance and the mechanism involved is proposed. We further demonstrate the novel use of such Fe-g-C3N4 as a cheap nanosensor for simple, rapid, highly selective and sensitive optical detection of glucose with a pretty low detection limit of 0.5 μM. PMID:24121798

  12. Synthesis and visible light photocatalysis of Fe-doped TiO{sub 2} mesoporous layers deposited on hollow glass microbeads

    SciTech Connect

    Cui Lifeng; Wang Yuansheng; Niu Mutong; Chen Guoxin; Cheng Yao

    2009-10-15

    Nano-composite of Fe-doped anatase TiO{sub 2} nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition and calcining treatment. The adherence of TiO{sub 2} mesoporous layers to the surfaces of hollow glass microbeads prevented the aggregation of TiO{sub 2} nanoparticles and benefited to their catalytic activity. The doping of Fe ions makes the absorption edge of the TiO{sub 2} based nano-composite red-shifted into the visible region. An effective photodegradation of the methyl orange aqueous solution was achieved under visible light (lambda>420 nm) irradiation, revealing the potential applicability of such nano-composite in some industry fields, such as air and water purifications. - Graphical abstract: Nano-composite of Fe-doped anatase TiO{sub 2} nanocrystals loaded on the hollow glass microbeads was prepared by co-thermal hydrolysis deposition. Photodegradation of the methyl orange was achieved under visible light irradiation, revealing the potential applicability of such nano-composite in some industry fields.

  13. Study of the relation between oxygen vacancies and ferromagnetism in Fe-doped TiO{sub 2} nano-powders

    SciTech Connect

    Mudarra Navarro, Azucena M.; Rodríguez Torres, Claudia E. Fabiana Cabrera, A.; Bilovol, Vitaliy; Errico, L. A.; Weissmann, M.

    2014-06-14

    In this work, we present an experimental and theoretical study of structural and magnetic properties of Fe doped rutile TiO{sub 2} nanopowders. We show that Fe-doping induces the formation of oxygen vacancies in the first-sphere coordination of iron ions, which are in +2 and +3 oxidation states. We found that Fe ions form dimers that share one oxygen vacancy in the case of Fe{sup 3+} and two oxygen vacancies in the case of Fe{sup 2+}. The saturation magnetization is almost independent of iron concentration and slightly increases with the relative fraction of Fe{sup 2+}. Ab initio calculations show that two Fe ions sharing an oxygen vacancy are coupled ferromagnetically, forming a bound magnetic polaron (BMP), but two neighbor BMPs are aligned antiparallel to each other. Extra electron doping plays a fundamental role mediating the magnetic coupling between the ferromagnetic entities: carriers, possibly concentrated at grain boundaries, mediate between the BMP to produce ferromagnetic alignment.

  14. Magnetism mediated by a majority of [Fe³⁺ + VO²⁻] complexes in Fe-doped CeO₂ nanoparticles.

    PubMed

    Paidi, V K; Ferreira, N S; Goltz, D; van Lierop, J

    2015-08-26

    We examine the role of Fe(3+) and vacancies (V(O)) on the magnetism of Fe-doped CeO2 nanoparticles. Magnetic nanoparticles of Ce(100-x)Fe(x)O2 (x  =  0, 0.26, 1.82, 2.64, 5.26, 6.91, and 7.22) were prepared by a co-precipitation method, and their structural, compositional and magnetic properties were investigated. The CeO2 nanoparticles had a mixed valance of Ce(4+) and Ce(3+) ions, and doping introduced Fe(3+) ions. The decrease in Ce(3+) and increase in Fe(3+) concentrations indicated the presence of more [Fe(3+) + V(O)(2-)] complexes with Fe loading in the particles. Charge neutralization, Fe(3+) + V(O)(2-) + 2Ce(4+) ↔ 2Ce(3+) + Fe(3+), identified the impact of V(O) on the magnetism, where our results suggest that the Fe-doped CeO2 nanoparticle magnetism is mediated by a majority of [Fe(3+) + V(O)(2-)]-Ce(3+) -[Fe(3+) + V(O)(2-)] complexes. PMID:26235592

  15. Structural and magnetic properties of pristine and Fe-doped NiO nanoparticles synthesized by the co-precipitation method

    SciTech Connect

    Mishra, A.K.; Das, D.

    2012-09-15

    Highlights: ► The prepared samples were characterized by XRD, TEM, HR-TEM techniques. ► Magnetic properties of the samples were compared. ► Surface spins frozen at lower temperatures resulted a spin glass. ► The samples show enhancement of coercivity with decreased temperature. -- Abstract: Ni{sub 1−x}Fe{sub x}O (x = 0 and 0.03) nanoparticles are synthesized by a chemical route. XRD and TEM measurements confirm phase purity and crystallinity of the nanoparticles. Fe substitution in NiO reduces considerably the average particle size of the nanoparticles. The pristine NiO sample with size 14 nm and Fe-substituted sample having size 7 nm show room temperature ferromagnetism. The pristine NiO having 31 nm size and Fe-substituted sample with size 25 nm are found to be antiferromagnetic. The M–H and M–T behavior of the pristine and Fe-doped samples are explained with a core–shell model with an antiferromagnetic core and a ferromagnetic shell. The disordered spins at the shell give rise to a spin-glass like frozen state below 10 K. The obtained room temperature ferromagnetism in the pristine and Fe-doped NiO has been attributed to particle size effect.

  16. Comparative study of the Raman vibrational modes in pure and Fe-doped La2/3Ca1/3MnO3 thin films

    NASA Astrophysics Data System (ADS)

    Arnache, O.; Osorio, J.

    2016-04-01

    A comparative study of Raman spectra at room temperature of La2/3Ca1/3MnO3 (LCMO) and La2/3Ca1/3Mn0.97Fe0.03O3 (LCMFO) thin films, grown on monocrystalline substrates LaAlO3, is presented. The films were grown with thickness between 30 and 130 nm under identical deposition conditions by DC magnetron sputtering system at high O2 pressure. In order to observe changes in the vibration modes of the lattice due to the substitution of Mn by Fe ions, we compared the different values of wave numbers obtained from the fittings of each Raman spectrum. The results show that the characteristic-and most intense-peak at ∼486 cm-1 corresponds to the substrate. In the LCMO thick films, Raman modes are very weak and mix up with the substrate one, whereas in LCMFO, these modes were found in three intervals around 220-250 cm-1 (υ1), 450-520 cm-1 (υ2) and 610-720 cm-1 (υ3). A mode at ∼717 cm-1 is associated to structural disorder due to Fe doping effect. In both LCMO and LCMFO films, the conduction mechanism are related with electron localization and the electronic transition is mediated by phonons. According to the T* values from resistivity data fit (Variable Range Model -VRH), it is observed once more that the Fe doping relaxes the strain effects.

  17. Observation of the large magnetocaloric effect and suppression of orbital entropy change in Fe-doped MnV{sub 2}O{sub 4}

    SciTech Connect

    Huang, Z. H.; Luo, X. E-mail: ypsun@issp.ac.cn; Hu, L.; Tan, S. G.; Liu, Y.; Yuan, B.; Chen, J.; Song, W. H.; Sun, Y. P. E-mail: ypsun@issp.ac.cn

    2014-01-21

    We present the structural and magnetic properties of Mn{sub 1−x}Fe{sub x}V{sub 2}O{sub 4} (x = 0.1, 0.2, and 0.3), and investigate the magnetocaloric effect in those compounds. The ferrimagnetic spin ordering is enhanced with the Fe doping at Mn site of MnV{sub 2}O{sub 4}, while the orbital ordering is suppressed. Large magnetic entropy changes up to 3.8 J/kg K as well as the relative cooling power up to 110 J/kg at the field change of 0-2 T for Mn{sub 1−x}Fe{sub x}V{sub 2}O{sub 4} are calculated from the isothermal magnetization measurements. The large orbital entropy change of MnV{sub 2}O{sub 4} is suppressed by the Fe doping, while the spin entropy contribution arising from the strong spin-orbit coupling remains. Moreover, the doping of Fe broadens the temperature span of the large magnetic entropy change and increases the relative cooling power of MnV{sub 2}O{sub 4} by 2.4 times.

  18. Calcium - ionized

    MedlinePlus

    ... at both ionized calcium and calcium attached to proteins. You may need to have a separate ionized calcium test if you have factors that increase or decrease total calcium levels. These may include abnormal blood levels ...

  19. Calcium Oscillations

    PubMed Central

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlying mechanism of calcium oscillations through the power of mathematical modeling. We also summarize recent findings on the role of calcium entry through store-operated channels in sustaining calcium oscillations and in the mechanism by which calcium oscillations couple to downstream effectors. PMID:21421924

  20. Sulfide Mineralogy and Geochemistry

    NASA Astrophysics Data System (ADS)

    Dilles, John

    2007-02-01

    Reviews in Mineralogy and Geochemistry Series, Volume 61 David J. Vaughan, Editor Geochemical Society and Mineralogical Society of America; ISBN 0-939950-73-1 xiii + 714 pp.; 2006; $40. Sulfide minerals as a class represent important minor rock-forming minerals, but they are generally known as the chief sources of many economic metallic ores. In the past two decades, sulfide research has been extended to include important roles in environmental geology of sulfide weathering and resultant acid mine drainage, as well as in geomicrobiology in which bacteria make use of sulfides for metabolic energy sources. In the latter respect, sulfides played an important role in early evolution of life on Earth and in geochemical cycling of elements in the Earth's crust and hydrosphere.

  1. Detection of Fe2+ valence states in Fe doped SrTiO3 epitaxial thin films grown by pulsed laser deposition.

    PubMed

    Koehl, Annemarie; Kajewski, Dariusz; Kubacki, Jerzy; Lenser, Christian; Dittmann, Regina; Meuffels, Paul; Szot, Kristof; Waser, Rainer; Szade, Jacek

    2013-06-01

    We present an X-ray absorption spectroscopy study on Fe-doped SrTiO3 thin films grown by pulsed laser deposition. The Fe L2,3 edge spectra are recorded for doping concentrations from 0-5% after several annealing steps at moderate temperatures. The Fe valence state is determined by comparison with an ilmenite reference sample and calculations according to the charge transfer multiplet model. We found clear evidence of Fe(2+) and Fe(3+) oxidation states independently of the doping concentration. The Fe(2+) signal is enhanced at the surface and increases after annealing. The Fe(2+) configuration is in contrast to the mixed Fe(3+)/Fe(4+) valence state in bulk material and must be explained by the specific defect structure of the thin films due to the kinetically limited growth which induces a high concentration of oxygen vacancies. PMID:23615619

  2. A comparative study of the defects in Fe-doped or undoped semi-insulating InP after high temperature annealing

    SciTech Connect

    Cherkaoui, K.; Kallel, S.; Marrakchi, G.; Karoui, A.

    1996-12-31

    Fe-doped or undoped semi-insulating InP samples submitted to high temperature annealing process have been studied by Photoinduced current transient spectroscopy (PICTS) in order to compare the traps observed. The PICTS spectra of these samples show separately the presence of a multitude of traps having activation energies ranging from 0.12 eV to 0.66 eV. The Fe{sub In} trap level has not been clearly observed in all the samples. The comparison of the thermal parameters of the observed traps allows to assign some of them to a same defect. However, the identification seems to be less evident concerning other traps and should be rather related to the properties of the starting material.

  3. Electronic, Energetic and Chemical Effects of Intrinsic Defects and Fe-Doping of CoAl2O4: A DFT+U Study

    SciTech Connect

    Walsh, A.; Yan, Y.; Al-Jassim, M. M.; Wei, S.-H.

    2008-01-01

    The spinel cobalt aluminate has gained interest as a potential photoelectrochemical catalyst for the renewable production of hydrogen. Using band structure theory, we determine the energetics of possible intrinsic point defects in spinel CoAl{sub 2}O{sub 4} and analyze their effect on its electronic and chemical properties. Extrinsic Fe-doping is also examined. Cation vacancies are found to be shallow acceptors, but their formation energy is sensitive to the growth conditions; an oxygen rich environment is required to enhance the p-type conductivity. Fe is an isovalent substituent on the Co (Al) site, exhibiting a preference for octahedral coordination, and forms a deep donor (acceptor) level near the center of the band gap, corresponding to a Fe(II) to Fe(III) transition.

  4. Fabrication of Fe-Doped LiCoO2 Sandwich-Like Nanocomposites as Excellent Performance Cathode Materials for Lithium-Ion Batteries.

    PubMed

    Liu, Li; Zhang, Huijuan; Yang, Jiao; Mu, Yanping; Wang, Yu

    2015-12-21

    In this article, the two-layer sandwiched graphene@LiFe0.Co0.8O2 nanoparticles (SG@LFCO) have been prepared and investigated as high-rate and long-life cathode materials for rechargeable lithium-ion batteries. The materials possess a high-surface area (267.1 m(2) g(-1)) and lots of void spaces. By combining various favorable conditions, such as Fe doping, coating graphene, and designing novel morphology, the as-prepared materials deliver a specific capacity of 115 mAh g(-1) at 10 C. At the 0.1 C cycling rate, the capacity retention of 97.2% is sustained after 250 cycles and a coulombic efficiency of around 97.6% is obtained. PMID:26552860

  5. Synthesis and characterization of UV-treated Fe-doped bismuth lanthanum titanate-doped TiO2 layers in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Song, Myoung Geun; Bark, Chung Wung

    2016-06-01

    Dye-sensitized solar cells (DSSCs) based on titanium dioxide (TiO2) have been extensively studied because they constitute promising low-cost alternatives to their conventional semiconductor-based counterparts. However, much of the effort aimed at achieving high conversion efficiencies has focused on dye and liquid electrolytes. In this work, we report the photovoltaic characteristics of DSSCs fabricated by mixing TiO2 with Fe-doped bismuth lanthanum titanate (Fe-BLT). These nanosized Fe-BLT powders were prepared by using a high-energy ball-milling process. In addition, we used a UV radiation-ozone (UV-O3) treatment to change the surface wettability of TiO2 from hydrophobic to hydrophilic and thereby prevented the easy separation of the Fe-BLT-mixed TiO2 from the fluorine-doped tin-oxide (FTO) coating glass.

  6. The properties of Co- and Fe-doped GDC for low-temperature processing of solid oxide fuel cell by electron-beam evaporation.

    PubMed

    Yang, Seon-Ho; Kim, Kyung-Hwan; Choi, Hyung-Wook

    2013-08-01

    This study is transition metal oxides (FeO and CoO) were added to Gd-doped ceria (Gd0.1Ce0.9O1.95, GDC) powder for preparing the thin-film electrolyte used in the Ni-GDC anode-supported intermediate temperature solid oxide fuel cell (SOFC). Recently much attention was aimed at successful powder preparation with high sinter activity and conductivity. However, one of the challenges in preparing the GDC electrolytes is the densification issue. It is difficult to achieve the densification of GDC below 1600 degrees C. To overcome this drawback, attentions of the research on the densification of the GDC electrolyte is paid more on changing of the fabrication technology, the powder properties, and the sintering mechanism. Among them, Fe3+ and Co2+ showed the significant beneficial effect on the grain boundary conductivity. So, electrolyte powder made of Co- and Fe-doped GDC by solid-state reaction method. And thin-film electrolyte was fabricated on the presintered Ni-GDC cermet anode substrate by E-beam evaporating method and then co-sintered to form the electrolyte/anode bilayer. We realized crystal structure of Co and Fe doped Gd0.1Ce0.9O1.95 (GDC) electrolyte by X-ray diffraction (XRD). The morphology was measured by scanning electron microscopy (SEM) for the sintered samples were performed. The performance of the cells was evaluated over 500-800 degrees C using humidified hydrogen as fuel and air as oxidant. PMID:23882837

  7. [Photoelectrocatalytic degradation of bisphenol A in water by Fe doped-TiO2 nanotube arrays under simulated solar light irradiation].

    PubMed

    Xiang, Guo-Liang; Yu, Ze-Bin; Chen, Ying; Xu, Tian-Zuo; Peng, Zhen-Bo; Liu, Yu-Xin

    2015-02-01

    Seeking an efficient treatment method for bisphenol A ( BPA), a representative endocrine disrupting compound, is important for environmental remediation and human health. Herein, the degradation of BPA by means of photoelectrocatalysis was investigated. Fe doped-TiO2 nanotube arrays ( Fe/TNA ) served as the photoanode, and a xenon lamp simulated the solar light source. First, undoped TiO2 nanotube arrays (TNA) and a series of Fe/TNA were characterized by field emission scanning electron microscopy, X-ray diffraction and UV-Vis diffuse reflectance spectroscopy. The UV-Vis absorption spectra of Fe/TNA showed a red-shift and an enhancement of the absorption in the visible-light region compared to TNA. Then, experimental conditions including Fe doping content, current intensity and aeration rate were varied to demonstrate their effects on the elimination of BPA. It was observed that the degradation of BPA could be fitted to the quasi-first-order equation. Under the following conditions: Fe/TNA prepared by 0.9 mol x L(-1) Fe(NO3)3 solution dip-coating as photoanode, titanium foil as cathode, current intensity of 1.15 mA x cm(-2) and initial BPA concentration of 10 mg x L(-1), 72.3% BPA was decomposed during 4 h reaction, with a rate constant of 5.32 x 10(-3) min(-1). Aeration enhanced the removal rate of BPA to 82.7% and 94.1% with an aerating rate of 1.0 L x min(-1) using titanium foil as cathode and an aerating rate of 0.2 L x min(-1) using carbon cloth as cathode, respectively, and the corresponding rate constants were 7.20 x 10(-3) min(-1) and 11.6 x 10(-3) min(-1), respectively. PMID:26031084

  8. Photocatalytic characteristics of single phase Fe-doped anatase TiO{sub 2} nanoparticles sensitized with vitamin B{sub 12}

    SciTech Connect

    Gharagozlou, Mehrnaz; Bayati, R.

    2015-01-15

    Highlights: • Anatase TiO{sub 2}/B{sub 12} hybrid nanostructured catalyst was successfully synthesized by sol–gel technique. • The nanoparticle catalyst was doped with iron at several concentrations. • Nanoparticles were characterized in detail by XRD, Raman, TEM, EDS, and spectroscopy techniques. • The formation mechanism and role of point defects on photocatalytic properties were discussed. • A structure-property-processing correlation was established. - Abstract: We report a processing-structure-property correlation in B{sub 12}-anatase titania hybrid catalysts doped with several concentrations of iron. Our results clearly show that low-level iron doping alters structure, defect content, and photocatalytic characteristics of TiO{sub 2}. XRD and Raman studies revealed formation of a single-phase anatase TiO{sub 2} where no iron based segregation in particular iron oxide, was detected. FT-IR spectra clearly confirmed sensitization of TiO{sub 2} nanoparticles with vitamin B{sub 12}. TEM micrographs and diffraction patterns confirmed crystallization of anatase nanoparticles with a radius of 15–20 nm. Both XRD and Raman signals showed a peak shift and a peak broadening which are surmised to originate from creation of point defects, namely oxygen vacancy and titanium interstitial. The doped samples revealed a narrower band gap as compared to undoped samples. Photocatalytic activity of the samples was assessed through measuring the decomposition rate of rhodamine B. It was found that sensitization with vitamin B{sub 12} and Fe-doping significantly enhances the photocatalytic efficiency of the anatase nanoparticles. We also showed that there is an optimum Fe-doping level where the maximum photocatalytic activity is achieved. The boost of photocatalytic activity was qualitatively understood to originate from a more effective use of the light photons, formation of point defects, which enhance the charge separation, higher carrier mobility.

  9. Removal of hydrogen sulfide from drilling fluids

    SciTech Connect

    Gilligan Jr., T. J.

    1985-10-22

    The present invention relates to a process for scavenging hydrogen sulfide which frequently becomes entrained in drilling fluid during the course of drilling operations through subterranean formations. The process consists of introducing a solid oxidant in powdered form into the circulating drilling fluid when hydrogen sulfide is encountered. The solid oxidants are selected from the group consisting of calcium hypochlorite (Ca-(OCl)/sub 2/), sodium perborate (NaBO/sub 3/), potassium permanganate (KMnO/sub 4/), and potassium peroxydisulfate (K/sub 2/S/sub 2/O/sub 8/). The solid oxidants are soluble in the drilling fluid, promoting fast and complete scavenging reactions without adversely altering the drilling fluid rheology.

  10. Calcium - urine

    MedlinePlus

    ... best treatment for the most common type of kidney stone , which is made of calcium. This type of ... the kidneys into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production ...

  11. Calcium Carbonate

    MedlinePlus

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  12. RECOVERY OF CALCIUM CARBONATE AND SULFUR FROM FGD SCRUBBER WASTE

    EPA Science Inventory

    The report gives results of a demonstration of key process steps in the proprietary Kel-S process for recovering calcium carbonate and sulfur from lime/limestone flue gas desulfurization (FGD) scrubber waste. The steps are: reduction of the waste to calcium sulfide (using coal as...

  13. Sulfidation of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Levard, C.; Michel, F. M.; Brown, G. E.

    2010-12-01

    Rapid development of nanotechnologies that exploit the properties of silver nanoparticles (Ag-NPs) raises questions concerning the impact of Ag on the environment. Ag-NPs are currently among the most widely used in the nanotechnology industry and the amount released into the environment is expected to increase along with production (1). When present in geochemical systems, Ag-NPs may undergo a variety of changes due to varying redox, pH, and chemical conditions. Expected changes range from surface modification (e.g., oxidation, sulfidation, chloridation etc.) to complete dissolution and re-precipitation. In this context, the focus of our work is on understanding the behavior of synthetic Ag-NPs with different particle sizes under varying conditions relevant to the environment. Sulfidation of Ag-NPs is of particular interest since it among the processes most likely to occur in aqueous systems, in particular under reducing conditions. Three sizes of Ag-NPs coated with polyvinyl pyrrolidone were produced using the polyol process (2) (7 ±1; 20 ±4, and 40 ±9 nm). Batch solutions containing the different Ag-NPs were subsequently reacted with Na2S solutions of different concentrations. The sulfidation process was followed step-wise for 24 hours and the corrosion products formed were characterized by electron microscopy (TEM/SEM), diffraction (XRD), and photo-electron spectroscopy (XPS). Surface charge (pHPZC) of the products formed during this process was also measured, as were changes in solubility and reactivity. Based on experimental observations we infer that the sulfidation process is the result of dissolution-precipitation and find that: (i) acanthite (Ag2S) is formed as a corrosion product; (ii) Ag-NPs aggregation increased with sulfidation rate; (iii) pHPZC increases with the rate of sulfidation; and (iv) the solubility of the corrosion products formed from sulfidation appears lower than that of non-sulfidated Ag-NPs. We observe size-dependent differences in

  14. A charge-based deep level transient spectroscopy measurement system and characterization of a ZnO-based varistor and a Fe-doped SrTiO3 dielectric

    NASA Astrophysics Data System (ADS)

    Okamoto, Takafumi; Long, Jeffrey; Wilke, Rudeger H. T.; Stitt, Joseph; Maier, Russell; Randall, Clive A.

    2016-02-01

    A charge-based deep level transient spectroscopy (Q-DLTS) method is applied to provide insights into the electronic behavior near grain boundaries and may provide new insights into mechanisms such as fatigue, degradation, dielectric aging, and dielectric breakdown. Here, we tested the Q-DLTS in both a ZnO varistor material and Fe-doped SrTiO3 materials. Comparisons are made to other data on ZnO varistors, and we obtain very good agreement for the energy levels. The status of deep traps in Fe-doped SrTiO3 dielectrics has been investigated where the relaxation was contrasted in a single crystal and polycrystalline ceramic materials. The relaxation is only observable in the polycrystalline materials, and was absent in single crystal Fe-doped crystals indicating that the deep traps originating from the Schottky barriers at the grain boundaries provide the DLTS signals. The energy associated with this grain boundary trap was found to be 1.26 eV.

  15. SULFIDE METHOD PLUTONIUM SEPARATION

    DOEpatents

    Duffield, R.B.

    1958-08-12

    A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.

  16. Characterization of Fe-doped In-Sb-Te (Fe: 10 at.%) material with individual electrical-phase-change and magnetic properties

    NASA Astrophysics Data System (ADS)

    Lee, Young Mi; Dung, Dang Duc; Cho, Sunglae; Jung, Min Sang; Choi, Duck Kyun; Ahn, Docheon; Kim, Min Kyu; Kim, Jae-Young; Jung, Min-Cherl

    2011-06-01

    We propose a new electrical-phase-change magnetic material, namely Fe-doped In-Sb-Te (FIST), for possible non-volatile multi-bit memory applications. FIST was formed by typical co-sputter method with Fe 10 at.% doping in In3Sb1Te2. FIST offers the electrical-phase-change and magnetic properties by way of the change of In 4d chemical bonding density and embedded Fe nanoclusters with the size of 4˜5 nm, respectively. It maintained the amorphous phase on the electrical-phase-change. Chemical state of In was only changed to increase the density of In-In chemical bonding during the electrical-phase-change without Fe nanoclusters contribution. Also, the magnetic property by Fe nanoclusters was not changed by the electrical-phase-change. On this basis, we propose the FIST material with the individual electrical-phase-change and magnetic properties for the multi-bit nonvolatile memory materials.

  17. Room temperature magnetism and metal to semiconducting transition in dilute Fe doped Sb1-xSex semiconducting alloy thin films

    NASA Astrophysics Data System (ADS)

    Agrawal, Naveen; Sarkar, Mitesh; Chawda, Mukesh; Ganesan, V.; Bodas, Dhananjay

    2015-02-01

    The magnetism was observed in very dilute Fe doped alloy thin film Fe0.008Sb1-xSex, for x = 0.01 to 0.10. These thin films were grown on silicon substrate using thermal evaporation technique. Structural, electrical, optical, charge carrier concentration measurement, surface morphology and magnetic properties were observed using glancing incidence x-ray diffraction (GIXRD), four probe resistivity, photoluminescence, Hall measurement, atomic force microscopy (AFM) and magnetic force microscopy (MFM) techniques, respectively. No peaks of iron were seen in GIXRD. The resistivity results show that activation energy increases with increase in selenium (Se) concentration. The Arrhenius plot reveals metallic behavior below room temperature. The low temperature conduction is explained by variable range-hopping mechanism, which fits very well in the temperature range 150-300 K. The decrease in density of states has been observed with increasing selenium concentration (x = 0.01 to 0.10). There is a metal-to-semiconductor phase transition observed above room temperature. This transition temperature is Se concentration dependent. The particle size distribution ˜47-61 nm is evaluated using AFM images. These thin films exhibit ferromagnetic interactions at room temperature.

  18. Fe doping effect on the structural, magnetic and surface properties of SnO2 nanoparticles prepared by a polymer precursor method

    NASA Astrophysics Data System (ADS)

    Aragón, F. H.; Coaquira, J. A. H.; Gonzalez, I.; Nagamine, L. C. C. M.; Macedo, W. A. A.; Morais, P. C.

    2016-04-01

    In this study the structural, magnetic and surface characterization of Fe-doped SnO2 nanopowders synthesized by a polymer precursor method is presented. The x-ray diffraction (XRD) data analysis shows the formation of rutile-type structure for all samples. For Fe-content up to 5.0 mol% lattice constants and unit cell volume values suggest substitutional solution of Fe3+- and Sn4+-ions in the SnO2 matrix and the likely generation of oxygen vacancies to account for charge compensation. Above 5.0 mol% Fe-content the entrance of Fe3+-ions into interstitial sites seems to be the dominant regime. Magnetic measurements confirm the ferric valence state and suggest the coexistence of weak ferromagnetic (FM) with strong paramagnetic (PM) phases. Using the bound magnetic polaron (BMP) model the FM contribution has been associated to electrons trapped within oxygen vacancies (donor electrons) that form BMPs which overlap to create a spin-split impurity band. Despite the small size of the particles no evidence of thermal relaxation effects has been observed, which was assigned to the formation of aggregates of strongly interacting naked particles. Above  ≈1.0 mol% Fe-content, the antiferromagnetic (AFM) interaction associated to Fe-clusters seems to be dominant and only a PM phase is observed. These results are consistent with XPS data analysis which indicates that the magnetic properties are strongly correlated with the surface properties of the particles.

  19. Moessbauer investigation of {sup 57}Fe doped La{sub 4}Ni{sub 3}O{sub 10{+-}}{sub y} phases

    SciTech Connect

    Carvalho, M.D.; Bassat, J.M.

    2009-01-15

    {sup 57}Fe doped La{sub 4}Ni{sub 2.97}Fe{sub 0.03}O{sub 9.95} was synthesized by a citrate method and, afterwards, successfully oxidized and reduced by electrochemical methods. The compounds obtained were investigated by X-ray diffraction, electrical measurements and Moessbauer spectroscopy. The study allowed to follow the variation of the two nickel sites environment with the oxygen stoichiometry and a deeper understanding of the electrical behavior versus oxygen non-stoichiometry was achieved. The Moessbauer study revealed that after both oxidation and reduction treatments, the major modifications were observed on the octahedra adjacent to the La{sub 2}O{sub 2} layers, while the middle octahedra of the triple perovskite block remained almost unchanged. The oxygen intercalation (oxidized treatment) takes place essentially in the La{sub 2}O{sub 2} layers and the oxygen desintercalation (reduction treatment) occurs in the octahedral sites adjacent to those layers. - Grapical abstract: Moessbauer spectra of oxidized and reduced Ruddlesden-Popper compounds La{sub 4}Ni{sub 2.97}Fe{sub 0.03}O{sub 10{+-}}{sub y}.

  20. Structural, XPS and magnetic studies of pulsed laser deposited Fe doped Eu{sub 2}O{sub 3} thin film

    SciTech Connect

    Kumar, Sandeep; Prakash, Ram; Choudhary, R.J.; Phase, D.M.

    2015-10-15

    Highlights: • Growth of Fe doped Eu{sub 2}O{sub 3} thin films by PLD. • XRD and Raman’s spectroscopy used for structure confirmation. • The electronic states of Eu and Fe are confirmed by XPS. • Magnetic properties reveals room temperature magnetic ordering in deposited film. - Abstract: Fe (4 at.%) doped europium (III) oxide thin film was deposited on silicon (1 0 0) substrate by pulsed laser deposition technique. Structural, spectral and magnetic properties were studied by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and magnetization measurements. XRD and Raman spectroscopy reveal that the grown film is single phased and belongs to the cubic structure of Eu{sub 2}O{sub 3}. XPS study of the Eu{sub 1.92}Fe{sub 0.08}O{sub 3} film shows that Fe exists in Fe{sup 3+} ionic state in the film. The film exhibits magnetic ordering at room temperature.

  1. Impedance spectra of Fe-doped SrTiO3 thin films upon bias voltage: inductive loops as a trace of ion motion.

    PubMed

    Taibl, S; Fafilek, G; Fleig, J

    2016-08-01

    Mass and charge transport properties of slightly Fe-doped SrTiO3 (Fe:STO) thin films on a conducting substrate were investigated by means of impedance spectroscopy under different bias voltages and I-V measurements with varying scan rates. At measurement temperatures between 325 °C and 700 °C the applied bias voltage caused an unusual "inductive loop" in the low frequency range of impedance spectra. DC measurements showed that current-voltage curves strongly depend on the scan rate, indicating that different states of the sample became accessible to probe. Both findings can be understood in terms of bias induced ion motion, i.e. by stoichiometry polarization within the Fe:STO thin films upon voltage. Hence, the appearance of an "inductive loop" in the impedance spectra is considered a very general feature that might exist for many materials, particularly in oxide thin films. It may indicate ion motion and stoichiometry variations taking place in the corresponding frequency range. PMID:27088884

  2. Facile preparation of novel dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes for excellent capacitive property in asymmetric supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Li; Zhang, Huijuan; Fang, Ling; Mu, Yanping; Wang, Yu

    2016-09-01

    In this work, we successfully synthesized the dandelion-like Fe-doped NiCo2O4 microspheres@nanomeshes (Fe-NCO-M@N-1h) using a facile hydrothermal method, followed by calcinations. In the unique structure, numerous nanoneedles radially grow on the surface of microsphere and some porous nanomeshes orderly develop in the inside of microsphere, therefore dandelion-like Fe-NCO-M@N-1h displays large specific surface area (101.15 m2 g-1) and more active sites. Electrochemical properties of the Fe-NCO-M@N-1h have been tested for symmetric supercapacitors (SCs) and asymmetric supercapacitors (ASCs). Benefiting from the structural advantages, Fe-NCO-M@N-1h electrode exhibits outstanding capacitive behaviors, such as the desirable specific capacitance and eminent rate performance (2237 and 1810 F g-1 at the current densities of 1 and 20 A g-1, respectively) and remarkable cycling performance (95.8% retention after 4500 cycles). Besides, a Fe-NCO-M@N-1h//AC-ASCs device has been constructed successfully, presenting the highest energy density of 46.68 Wh kg-1. The results indicate that the Fe-NCO-M@N-1h is a potential material for SCs.

  3. A novel disposable electrochemical sensor for determination of carbamazepine based on Fe doped SnO2 nanoparticles modified screen-printed carbon electrode.

    PubMed

    Lavanya, N; Sekar, C; Ficarra, S; Tellone, E; Bonavita, A; Leonardi, S G; Neri, G

    2016-05-01

    An effective strategy to fabricate a novel disposable screen printing carbon electrode modified by iron doped tin dioxide nanoparticles for carbamazepine (CBZ) detection has been developed. Fe-SnO2 (Fe=0 to 5 wt.%) NPs were synthesized by a simple microwave irradiation method and assessed for their structural and morphological changes due to Fe doping into SnO2 matrix by X-ray diffraction and scanning and transmission electron microscopy. The electrochemical behaviour of carbamazepine at the Fe-SnO2 modified screen printed carbon electrode (SPCE) was investigated by cyclic voltammetry and square wave voltammetry. Electron transfer coefficient α (0.63) and electron transfer rate constant ks (0.69 s(-1)) values of the 5 wt.% Fe-SnO2 modified SPCE indicate that the diffusion controlled process takes place on the electrode surface. The fabricated sensor displayed a good electrooxidation response towards the detection of CBZ at a lower oxidation potential of 0.8 V in phosphate buffer solution at pH7.0. Under the optimal conditions, the sensor showed fast and sensitive current response to CBZ over a wide linear range of 0.5-100 μM with a low detection limit of 92 nM. Furthermore, the practical application of the modified electrode has been investigated by the determination of CBZ in pharmaceutical products using standard addition method. PMID:26952397

  4. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  5. Sulfidation kinetics of silver nanoparticles reacted with metal sulfides.

    PubMed

    Thalmann, Basilius; Voegelin, Andreas; Sinnet, Brian; Morgenroth, Eberhard; Kaegi, Ralf

    2014-05-01

    Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions. We reacted citrate-stabilized Ag-NP of different sizes (10-100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu(2+) or Zn(2+) over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag2S within a few hours to days by reaction with metal sulfides. PMID:24678586

  6. Calcium - urine

    MedlinePlus

    ... into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production of ... Milk-alkali syndrome Proximal renal tubular acidosis Rickets Sarcoidosis Vitamin D Update Date 5/3/2015 Updated ...

  7. Calcium supplements

    MedlinePlus

    ... SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the human body. It helps build and protect your teeth ... absorb calcium. You can get vitamin D from sunlight exposure to your skin and from your diet. Ask your provider whether ...

  8. Sulfide detoxification in plant mitochondria.

    PubMed

    Birke, Hannah; Hildebrandt, Tatjana M; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    In contrast to animals, which release the signal molecule sulfide in small amounts from cysteine and its derivates, phototrophic eukaryotes generate sulfide as an essential intermediate of the sulfur assimilation pathway. Additionally, iron-sulfur cluster turnover and cyanide detoxification might contribute to the release of sulfide in mitochondria. However, sulfide is a potent inhibitor of cytochrome c oxidase in mitochondria. Thus, efficient sulfide detoxification mechanisms are required in mitochondria to ensure adequate energy production and consequently survival of the plant cell. Two enzymes have been recently described to catalyze sulfide detoxification in mitochondria of Arabidopsis thaliana, O-acetylserine(thiol)lyase C (OAS-TL C), and the sulfur dioxygenase (SDO) ethylmalonic encephalopathy protein 1 (ETHE1). Biochemical characterization of sulfide producing and consuming enzymes in mitochondria of plants is fundamental to understand the regulatory network that enables mitochondrial sulfide homeostasis under nonstressed and stressed conditions. In this chapter, we provide established protocols to determine the activity of the sulfide releasing enzyme β-cyanoalanine synthase as well as sulfide-consuming enzymes OAS-TL and SDO. Additionally, we describe a reliable and efficient method to purify OAS-TL proteins from plant material. PMID:25747485

  9. Geothermal hydrogen sulfide removal

    SciTech Connect

    Urban, P.

    1981-04-01

    UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

  10. Biotreatment of refinery spent sulfidic caustics

    SciTech Connect

    Sublette, K.L.; Rajganesh, B.; Woolsey, M.; Plato, A.

    1995-12-31

    Caustics are used in petroleum refinering to remove hydrogen sulfide from various hydrocarbon streams. Spent sulfidic caustics from two Conoco refineries have been successfully biotreated on bench and pilot scale, resulting in neutralization and removal of active sulfides. Sulfides were completely oxidized to sulfate by Thiobacillus denitrificans. Microbial oxidation of sulfide produced acid, which at least partially neutralized the caustic.

  11. Hydrogen sulfide intoxication.

    PubMed

    Guidotti, Tee L

    2015-01-01

    Hydrogen sulfide (H2S) is a hazard primarily in the oil and gas industry, agriculture, sewage and animal waste handling, construction (asphalt operations and disturbing marshy terrain), and other settings where organic material decomposes under reducing conditions, and in geothermal operations. It is an insoluble gas, heavier than air, with a very low odor threshold and high toxicity, driven by concentration more than duration of exposure. Toxicity presents in a unique, reliable, and characteristic toxidrome consisting, in ascending order of exposure, of mucosal irritation, especially of the eye ("gas eye"), olfactory paralysis (not to be confused with olfactory fatigue), sudden but reversible loss of consciousness ("knockdown"), pulmonary edema (with an unusually favorable prognosis), and death (probably with apnea contributing). The risk of chronic neurcognitive changes is controversial, with the best evidence at high exposure levels and after knockdowns, which are frequently accompanied by head injury or oxygen deprivation. Treatment cannot be initiated promptly in the prehospital phase, and currently rests primarily on supportive care, hyperbaric oxygen, and nitrite administration. The mechanism of action for sublethal neurotoxicity and knockdown is clearly not inhibition of cytochrome oxidase c, as generally assumed, although this may play a role in overwhelming exposures. High levels of endogenous sulfide are found in the brain, presumably relating to the function of hydrogen sulfide as a gaseous neurotransmitter and immunomodulator. Prevention requires control of exposure and rigorous training to stop doomed rescue attempts attempted without self-contained breathing apparatus, especially in confined spaces, and in sudden release in the oil and gas sector, which result in multiple avoidable deaths. PMID:26563786

  12. ac susceptibility studies in Fe doped La0.65Ca0.35Mn1-xFexO3: Rare earth manganites

    NASA Astrophysics Data System (ADS)

    Shah, Wiqar Hussain; Hasanain, S. K.

    2010-12-01

    The effects of Fe substitution on Mn sites in the colossal magnetoresistive compounds La0.65Ca0.35Mn1-xFexO3 with 0.00≤x≤0.10 have been studied. A careful study in the magnetic properties has been carried out by the measurement of magnetic ac susceptibility. The temperature range of colossal magnetoresistance (CMR) is greatly broadened with the addition of Fe. Substitution of Fe induces a gradual transition from a metallic ferromagnetic with a high Curie temperature (Tc=270 K) to a ferromagnetic insulator with low Tc=79 K. Increased spin disorder and decrease of Tc with increasing Fe content are evident. The variations in the critical temperature Tc and magnetic moment show a rapid change at about 4%-5% Fe. The effect of Fe is seen to be consistent with the disruption of the Mn-Mn exchange possibly due to the formation of magnetic clusters. An extraordinary behavior in the out of phase part (χ″) of ac susceptibility, characterized by double bump (shoulder), was observed around x=0.01 and 0.02. The shoulder in χ″ disappears at x≥0.04 Fe concentration. With increasing Fe concentration the χ″ peak shift to TFe doping. Doping with Fe bypasses the usually dominant lattice effects, but depopulates the hopping electrons and thus weakens the double exchange. The results were explained in terms of the formation of magnetic clusters of Fe ions.

  13. Field method for sulfide determination

    SciTech Connect

    Wilson, B L; Schwarser, R R; Chukwuenye, C O

    1982-01-01

    A simple and rapid method was developed for determining the total sulfide concentration in water in the field. Direct measurements were made using a silver/sulfide ion selective electrode in conjunction with a double junction reference electrode connected to an Orion Model 407A/F Specific Ion Meter. The method also made use of a sulfide anti-oxidant buffer (SAOB II) which consists of ascorbic acid, sodium hydroxide, and disodium EDTA. Preweighed sodium sulfide crystals were sealed in air tight plastic volumetric flasks which were used in standardization process in the field. Field standards were prepared by adding SAOB II to the flask containing the sulfide crystals and diluting it to the mark with deionized deaerated water. Serial dilutions of the standards were used to prepare standards of lower concentrations. Concentrations as low as 6 ppB were obtained on lake samples with a reproducibility better than +- 10%.

  14. Calcium antagonists.

    PubMed

    Grossman, Ehud; Messerli, Franz H

    2004-01-01

    Calcium antagonists were introduced for the treatment of hypertension in the 1980s. Their use was subsequently expanded to additional disorders, such as angina pectoris, paroxysmal supraventricular tachycardias, hypertrophic cardiomyopathy, Raynaud phenomenon, pulmonary hypertension, diffuse esophageal spasms, and migraine. Calcium antagonists as a group are heterogeneous and include 3 main classes--phenylalkylamines, benzothiazepines, and dihydropyridines--that differ in their molecular structure, sites and modes of action, and effects on various other cardiovascular functions. Calcium antagonists lower blood pressure mainly through vasodilation and reduction of peripheral resistance. They maintain blood flow to vital organs, and are safe in patients with renal impairment. Unlike diuretics and beta-blockers, calcium antagonists do not impair glucose metabolism or lipid profile and may even attenuate the development of arteriosclerotic lesions. In long-term follow-up, patients treated with calcium antagonists had development of less overt diabetes mellitus than those who were treated with diuretics and beta-blockers. Moreover, calcium antagonists are able to reduce left ventricular mass and are effective in improving anginal pain. Recent prospective randomized studies attested to the beneficial effects of calcium antagonists in hypertensive patients. In comparison with placebo, calcium antagonist-based therapy reduced major cardiovascular events and cardiovascular death significantly in elderly hypertensive patients and in diabetic patients. In several comparative studies in hypertensive patients, treatment with calcium antagonists was equally effective as treatment with diuretics, beta-blockers, or angiotensin-converting enzyme inhibitors. From these studies, it seems that a calcium antagonist-based regimen is superior to other regimens in preventing stroke, equivalent in preventing ischemic heart disease, and inferior in preventing congestive heart failure

  15. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  16. Photovoltaic semiconductor materials based on alloys of tin sulfide, and methods of production

    DOEpatents

    Lany, Stephan

    2016-06-07

    Photovoltaic thin-film materials comprising crystalline tin sulfide alloys of the general formula Sn.sub.1-x(R).sub.xS, where R is selected from magnesium, calcium and strontium, as well as methods of producing the same, are disclosed.

  17. Sulfide Mineral Surfaces

    SciTech Connect

    Rosso, Kevin M.; Vaughan, David J.

    2006-08-01

    The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

  18. Calcium - ionized

    MedlinePlus

    ... levels. These may include abnormal blood levels of albumin or immunoglobulins. Normal Results Children: 4.8 to ... 2016:chap 245. Read More Acute kidney failure Albumin - blood (serum) test Bone tumor Calcium blood test ...

  19. Calcium Test

    MedlinePlus

    ... as thyroid disease , parathyroid disorder , malabsorption , cancer, or malnutrition An ionized calcium test may be ordered when ... albumin , which can result from liver disease or malnutrition , both of which may result from alcoholism or ...

  20. Calcium Calculator

    MedlinePlus

    ... with Sarcopenia Skeletal Rare Disorders Data & Publications Facts and Statistics Vitamin D map Fracture Risk Map Hip Fracture ... Training Courses Working Groups Regional Audits Reports Facts and Statistics Popular content Calcium content of common foods What ...

  1. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables. PMID:26940168

  2. Electrobioleaching of base metal sulfides

    NASA Astrophysics Data System (ADS)

    Natarajan, K. A.

    1992-01-01

    Bioleaching of base metal sulfides, such as pyrite, chalcopyrite, and sphalerite, under the influence of applied direct current (DC) potentials is discussed. Contributions toward mineral dissolution from three effects, namely, galvanic, applied potential, and microbiological, are analyzed and compared. Sphalerite could be selectively bioleached in the presence of Thiobacillus ferrooxidans under an applied potential of -500 mV (SCE) from mixed sulfides containing sphalerite, pyrite, and chalcopyrite. Bacterial activity and growth were found to be promoted under electrobioleaching conditions. Probable mechanisms involved in the bioleaching of different sulfides under positive and negative applied potentials are discussed.

  3. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  4. Calcium Hydroxylapatite

    PubMed Central

    Yutskovskaya, Yana Alexandrovna; Philip Werschler, WM.

    2015-01-01

    Background: Calcium hydroxylapatite is one of the most well-studied dermal fillers worldwide and has been extensively used for the correction of moderate-to-severe facial lines and folds and to replenish lost volume. Objectives: To mark the milestone of 10 years of use in the aesthetic field, this review will consider the evolution of calcium hydroxylapatite in aesthetic medicine, provide a detailed injection protocol for a global facial approach, and examine how the unique properties of calcium hydroxylapatite provide it with an important place in today’s market. Methods: This article is an up-to-date review of calcium hydroxylapatite in aesthetic medicine along with procedures for its use, including a detailed injection protocol for a global facial approach by three expert injectors. Conclusion: Calcium hydroxylapatite is a very effective agent for many areas of facial soft tissue augmentation and is associated with a high and well-established safety profile. Calcium hydroxylapatite combines high elasticity and viscosity with an ability to induce long-term collagen formation making it an ideal agent for a global facial approach. PMID:25610523

  5. A novel method for improving cerussite sulfidization

    NASA Astrophysics Data System (ADS)

    Feng, Qi-cheng; Wen, Shu-ming; Zhao, Wen-juan; Cao, Qin-bo; Lü, Chao

    2016-06-01

    Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.

  6. Prevention of sulfide oxidation in sulfide-rich waste rock

    NASA Astrophysics Data System (ADS)

    Nyström, Elsa; Alakangas, Lena

    2015-04-01

    The ability to reduce sulfide oxidation in waste rock after mine closure is a widely researched area, but to reduce and/or inhibit the oxidation during operation is less common. Sulfide-rich (ca 30 % sulfur) waste rock, partially oxidized, was leached during unsaturated laboratory condition. Trace elements such as As and Sb were relatively high in the waste rock while other sulfide-associated elements such as Cu, Pb and Zn were low compared to common sulfide-rich waste rock. Leaching of unsaturated waste rock lowered the pH, from around six down to two, resulting in continuously increasing element concentrations during the leaching period of 272 days. The concentrations of As (65 mg/L), Cu (6.9 mg/L), Sb (1.2 mg/L), Zn (149 mg/L) and S (43 g/L) were strongly elevated at the end of the leaching period. Different alkaline industrial residues such as slag, lime kiln dust and cement kiln dust were added as solid or as liquid to the waste rock in an attempt to inhibit sulfide oxidation through neo-formed phases on sulfide surfaces in order to decrease the mobility of metals and metalloids over longer time scale. This will result in a lower cost and efforts of measures after mine closure. Results from the experiments will be presented.

  7. Apparatus for use in sulfide chemiluminescence detection

    DOEpatents

    Spurlin, S.R.; Yeung, E.S.

    1987-01-06

    A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction. 4 figs.

  8. Apparatus for use in sulfide chemiluminescence detection

    DOEpatents

    Spurlin, Stanford R.; Yeung, Edward S.

    1987-01-01

    A method of chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only to the detection method, but the novel chemical reaction and a specifically designed chemiluminescence detection cell for the reaction.

  9. Thermoelectric Properties of Lanthanum Sulfide

    NASA Technical Reports Server (NTRS)

    Wood, C.; Lockwood, R.; Parker, J. B.; Zoltan, A.; Zoltan, L. D.; Danielson, L.; Raag, V.

    1987-01-01

    Report describes measurement of Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall effect in gamma-phase lanthanum sulfide with composition of La3-x S4. Results of study, part of search for high-temperature thermoelectric energy-conversion materials, indicate this sulfide behaves like extrinsic semiconductor over temperature range of 300 to 1,400 K, with degenerate carrier concentration controlled by stoichiometric ratio of La to S.

  10. Hydrogen Sulfide Oxidation by Myoglobin.

    PubMed

    Bostelaar, Trever; Vitvitsky, Victor; Kumutima, Jacques; Lewis, Brianne E; Yadav, Pramod K; Brunold, Thomas C; Filipovic, Milos; Lehnert, Nicolai; Stemmler, Timothy L; Banerjee, Ruma

    2016-07-13

    Enzymes in the sulfur network generate the signaling molecule, hydrogen sulfide (H2S), from the amino acids cysteine and homocysteine. Since it is toxic at elevated concentrations, cells are equipped to clear H2S. A canonical sulfide oxidation pathway operates in mitochondria, converting H2S to thiosulfate and sulfate. We have recently discovered the ability of ferric hemoglobin to oxidize sulfide to thiosulfate and iron-bound hydropolysulfides. In this study, we report that myoglobin exhibits a similar capacity for sulfide oxidation. We have trapped and characterized iron-bound sulfur intermediates using cryo-mass spectrometry and X-ray absorption spectroscopy. Further support for the postulated intermediates in the chemically challenging conversion of H2S to thiosulfate and iron-bound catenated sulfur products is provided by EPR and resonance Raman spectroscopy in addition to density functional theory computational results. We speculate that the unusual sensitivity of skeletal muscle cytochrome c oxidase to sulfide poisoning in ethylmalonic encephalopathy, resulting from the deficiency in a mitochondrial sulfide oxidation enzyme, might be due to the concentration of H2S by myoglobin in this tissue. PMID:27310035

  11. Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO₃-xBaTiO₃ piezoelectric ceramics

    SciTech Connect

    Sapper, Eva; Dittmer, Robert; Rödel, Jürgen; Damjanovic, Dragan; Erdem, Emre; Keeble, David J.; Jo, Wook; Granzow, Torsten

    2014-09-14

    Aging of piezoelectric properties was investigated in lead-free (1–x)(Bi{sub 1/2}Na{sub 1/2})TiO₃-xBaTiO₃ doped with 1at.% Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging phenomena are similar to those found in lead zirconate titanate or barium titanate. Most prominent aging effects are the development of an internal bias field and the decrease of switchable polarization. These effects are temperature activated, and can be explained in the framework of defect complex reorientation. This picture is further supported by electron paramagnetic resonance spectra indicating the existence of (Fe{sub Ti}´-V{sub O}{sup ••}){sup •} defect complexes in the Fe-doped material.

  12. Calcium and bones

    MedlinePlus

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  13. Get Enough Calcium

    MedlinePlus

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  14. Calcium carbonate overdose

    MedlinePlus

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  15. Calcium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for calcium cyanide is included in th

  16. Inhaled Hydrogen Sulfide

    PubMed Central

    Volpato, Gian Paolo; Searles, Robert; Yu, Binglan; Scherrer-Crosbie, Marielle; Bloch, Kenneth D.; Ichinose, Fumito; Zapol, Warren M.

    2010-01-01

    Background Breathing hydrogen sulfide (H2S) has been reported to induce a suspended animation–like state with hypothermia and a concomitant metabolic reduction in rodents. However, the impact of H2S breathing on cardiovascular function remains incompletely understood. In this study, the authors investigated the cardiovascular and metabolic effects of inhaled H2S in a murine model. Methods The impact of breathing H2S on cardiovascular function was examined using telemetry and echocardiography in awake mice. The effects of breathing H2S on carbon dioxide production and oxygen consumption were measured at room temperature and in a warmed environment. Results Breathing H2S at 80 parts per million by volume at 27°C ambient temperature for 6 h markedly reduced heart rate, core body temperature, respiratory rate, and physical activity, whereas blood pressure remained unchanged. Echocardiography demonstrated that H2S exposure decreased both heart rate and cardiac output but preserved stroke volume. Breathing H2S for 6 h at 35°C ambient temperature (to prevent hypothermia) decreased heart rate, physical activity, respiratory rate, and cardiac output without altering stroke volume or body temperature. H2S breathing seems to induce bradycardia by depressing sinus node activity. Breathing H2S for 30 min decreased whole body oxygen consumption and carbon dioxide production at either 27° or 35°C ambient temperature. Both parameters returned to baseline levels within 10 min after the cessation of H2S breathing. Conclusions Inhalation of H2S at either 27° or 35°C reversibly depresses cardiovascular function without changing blood pressure in mice. Breathing H2S also induces a rapidly reversible reduction of metabolic rate at either body temperature. PMID:18362598

  17. Enhancement of CO2 Adsorption and Catalytic Properties by Fe-Doping of [Ga2(OH)2(L)] (H4L = Biphenyl-3,3′,5,5′-tetracarboxylic Acid), MFM-300(Ga2)

    PubMed Central

    2016-01-01

    Metal–organic frameworks (MOFs) are usually synthesized using a single type of metal ion, and MOFs containing mixtures of different metal ions are of great interest and represent a methodology to enhance and tune materials properties. We report the synthesis of [Ga2(OH)2(L)] (H4L = biphenyl-3,3′,5,5′-tetracarboxylic acid), designated as MFM-300(Ga2), (MFM = Manchester Framework Material replacing NOTT designation), by solvothermal reaction of Ga(NO3)3 and H4L in a mixture of DMF, THF, and water containing HCl for 3 days. MFM-300(Ga2) crystallizes in the tetragonal space group I4122, a = b = 15.0174(7) Å and c = 11.9111(11) Å and is isostructural with the Al(III) analogue MFM-300(Al2) with pores decorated with −OH groups bridging Ga(III) centers. The isostructural Fe-doped material [Ga1.87Fe0.13(OH)2(L)], MFM-300(Ga1.87Fe0.13), can be prepared under similar conditions to MFM-300(Ga2) via reaction of a homogeneous mixture of Fe(NO3)3 and Ga(NO3)3 with biphenyl-3,3′,5,5′-tetracarboxylic acid. An Fe(III)-based material [Fe3O1.5(OH)(HL)(L)0.5(H2O)3.5], MFM-310(Fe), was synthesized with Fe(NO3)3 and the same ligand via hydrothermal methods. [MFM-310(Fe)] crystallizes in the orthorhombic space group Pmn21 with a = 10.560(4) Å, b = 19.451(8) Å, and c = 11.773(5) Å and incorporates μ3-oxo-centered trinuclear iron cluster nodes connected by ligands to give a 3D nonporous framework that has a different structure to the MFM-300 series. Thus, Fe-doping can be used to monitor the effects of the heteroatom center within a parent Ga(III) framework without the requirement of synthesizing the isostructural Fe(III) analogue [Fe2(OH)2(L)], MFM-300(Fe2), which we have thus far been unable to prepare. Fe-doping of MFM-300(Ga2) affords positive effects on gas adsorption capacities, particularly for CO2 adsorption, whereby MFM-300(Ga1.87Fe0.13) shows a 49% enhancement of CO2 adsorption capacity in comparison to the homometallic parent material. We thus report herein the

  18. Sulfur and sulfides in chondrules

    NASA Astrophysics Data System (ADS)

    Marrocchi, Yves; Libourel, Guy

    2013-10-01

    The nature and distribution of sulfides within type I PO, POP and PP chondrules of the carbonaceous chondrite Vigarano (CV3) have been studied by secondary electron microscopy and electron microprobe. They occur predominantly as spheroidal blebs composed entirely of low-Ni iron sulfide (troilite, FeS) or troilite + magnetite but in less abundance in association with metallic Fe-Ni beads in opaque assemblages. Troilites are mainly located within the low-Ca pyroxene outer zone and their amounts increase with the abundance of low-Ca pyroxene within chondrules, suggesting co-crystallization of troilite and low-Ca pyroxene during high-temperature events. We show that sulfur concentration and sulfide occurrence in chondrules obey high temperature sulfur solubility and saturation laws. Depending on the fS2 and fO2 of the surrounding gas and on the melt composition, mainly the FeO content, sulfur dissolved in chondrule melts may eventually reach a concentration limit, the sulfur content at sulfide saturation (SCSS), at which an immiscible iron sulfide liquid separates from the silicate melt. The occurrence of both a silicate melt and an immiscible iron sulfide liquid is further supported by the non-wetting behavior of sulfides on silicate phases in chondrules due to the high interfacial tension between their precursor iron-sulfide liquid droplets and the surrounding silicate melt during the high temperature chondrule-forming event. The evolution of chondrule melts from PO to PP towards more silicic compositions, very likely due to high PSiO(g) of the surrounding nebular gas, induces saturation of FeS at much lower S content in PP than in PO chondrules, leading to the co-crystallization of iron sulfides and low-Ca pyroxenes. Conditions of co-saturation of low-Ca pyroxene and FeS are only achieved in non canonical environments characterized by high partial pressures of sulfur and SiO and redox conditions more oxidizing than IW-3. Fe and S mass balance calculations also

  19. Mechanistic chemical perspective of hydrogen sulfide signaling.

    PubMed

    Nagy, Péter

    2015-01-01

    Hydrogen sulfide is now a well-appreciated master regulator in a diverse array of physiological processes. However, as a consequence of the rapid growth of the area, sulfide biology suffers from an increasing number of controversial observations and interpretations. A better understanding of the underlying molecular pathways of sulfide's actions is key to reconcile controversial issues, which calls for rigorous chemical/biochemical investigations. Protein sulfhydration and coordination/redox chemical interactions of sulfide with heme proteins are the two most extensively studied pathways in sulfide biochemistry. These pathways are important mediators of protein functions, generate bioactive sulfide metabolites, contribute to sulfide storage/trafficking and carry antioxidant functions. In addition, inorganic polysulfides, which are oxidative sulfide metabolites, are increasingly recognized as important players in sulfide biology. This chapter provides an overview of our mechanistic perspective on the reactions that govern (i) sulfide's bioavailability (including the delicate enzyme machineries that orchestrate sulfide production and consumption and the roles of the large sulfide-storing pools as biological buffers), (ii) biological significance and mechanisms of persulfide formation (including the reduction of disulfides, condensation with sulfenic acids, oxidation of thiols with polysulfides and radical-mediated pathways), (iii) coordination and redox chemical interactions of sulfide with heme proteins (including cytochrome c oxidase, hemoglobins, myoglobins and peroxidases), and (iv) the chemistry of polysulfides. PMID:25725513

  20. Sulfide Stability of Planetary Basalts

    NASA Technical Reports Server (NTRS)

    Caiazza, C. M.; Righter, K.; Gibson, E. K., Jr.; Chesley, J. T.; Ruiz, J.

    2004-01-01

    The isotopic system, 187Re 187Os, can be used to determine the role of crust and mantle in magma genesis. In order to apply the system to natural samples, we must understand variations in Re/Os concentrations. It is thought that low [Os] and [Re] in basalts can be attributed to sulfide (FeS) saturation, as Re behaves incompatibly to high degrees of evolution until sulfide saturation occurs [1]. Previous work has shown that lunar basalts are sulfide under-saturated, and mid-ocean ridge, ocean-island and Martian (shergottites) basalts are saturated [2,3]. However, little is known about arc basalts. In this study, basaltic rocks were analyzed across the Trans-Mexican Volcanic Belt.

  1. A Reaction Involving Oxygen and Metal Sulfides.

    ERIC Educational Resources Information Center

    Hill, William D. Jr.

    1986-01-01

    Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

  2. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Hydrogen sulfide. 250.604 Section 250.604...-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined...

  3. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or...

  4. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or...

  5. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL... § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or...

  6. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Hydrogen sulfide. 250.504 Section 250.504...-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined...

  7. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of...

  8. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  9. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  10. Nanostructured metal sulfides for energy storage.

    PubMed

    Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

    2014-09-01

    Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices. PMID:25073046

  11. 30 CFR 250.490 - Hydrogen sulfide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Hydrogen sulfide. 250.490 Section 250.490 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Hydrogen Sulfide § 250.490 Hydrogen sulfide. (a)...

  12. Synthesis and Characterization of Iron-Doped Lead Sulfide Thin Films

    NASA Astrophysics Data System (ADS)

    Gülen, Yasir

    2015-10-01

    Thin films have improved the semiconductor device technology because their material characteristics could be changed in many different ways including changing the crystal morphology and size. This study reports manufacturing undoped and Fe-doped nanostructured PbS films on glass substrates by SILAR method. Both undoped and Fe-doped films are examined in terms of structural, optical, and morphological properties via SEM, Uv-vis spectrophotometry, and XRF analysis. Results revealed that all of the thin films were in a face-centered cubic structure and concentration of Fe doping influences the size of the thin film's nanoparticles. The optical band gap of the PbS films decreased as Fe-doping concentration is increased. The intercept values on the energy axis were in the range of 1.66 and 1.25 eV for 1 and 9 pct Fe-doped PbS films, respectively. The structural, optical, and morphological properties of the fabricated thin films directly depend on the Fe-doping ratio.

  13. SULFIDE PRECIPITATION OF HEAVY METALS

    EPA Science Inventory

    The research program was initiated with the objective of evaluating a new process, the sulfide precipitation of heavy metals from industrial wastewaters. The process was expected to effect a more complete removal of heavy metals than conventional lime processing because of the mu...

  14. p-Chlorophenyl methyl sulfide

    Integrated Risk Information System (IRIS)

    p - Chlorophenyl methyl sulfide ; CASRN 123 - 09 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for N

  15. Platinum metals magmatic sulfide ores.

    PubMed

    Naldrett, A J; Duke, J M

    1980-06-27

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example. PMID:17796685

  16. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

    1994-01-01

    A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  17. Method of removing hydrogen sulfide from gases utilizing a zinc oxide sorbent and regenerating the sorbent

    DOEpatents

    Jalan, Vinod M.; Frost, David G.

    1984-01-01

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500.degree. C. to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent.

  18. Efficient new process for the desulfurization of mixtures of air and hydrogen sulfide via a dielectric barrier discharge plasma

    NASA Astrophysics Data System (ADS)

    Dahle, S.

    2015-10-01

    The efficient removal of hydrogen sulfide, H2S, from streams of H2S in air via a dielectric barrier discharge (DBD) plasma has been investigated using a quadrupole mass spectrometer. A suitable plasma device with a reservoir for storing sorbent powder of various kinds within the plasma region was constructed. Plasma treatments of gas streams with high concentrations of hydrogen sulfide in air yielded a removal of more than 98% of the initial hydrogen sulfide and a deposition of sulfur at the surface of the dielectric, while small amounts of sulfur dioxide were generated. The presence of calcium carbonate within the plasma region of the DBD device resulted in the removal of over 99% of the initial hydrogen sulfide content and the removal of 98% of the initial sulfur dioxide impurities from the gas mixture.

  19. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium ...

  20. Calcium and bones (image)

    MedlinePlus

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  1. Calcium source (image)

    MedlinePlus

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  2. Coronary Calcium Scan

    MedlinePlus

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  3. Calcium hydroxide poisoning

    MedlinePlus

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  4. SURFACE AREA OF CALCIUM OXIDE AND KINETICS OF CALCIUM SULFIDE FORMATION

    EPA Science Inventory

    The article gives results of measurements of the reaction rates of H2S and COS with micrometer-size calcined limestone particles, as a function of the B.E.T. surface area of the CaO over the range of 5.8 to 79 sq m/g. Reactivity increased with the 2.3 power of specific surface ar...

  5. Marine diagenesis of hydrothermal sulfide

    SciTech Connect

    Moammar, M.O.

    1985-01-01

    An attempt is made to discuss the artificial and natural oxidation and hydrolysis of hydrothermal sulfide upon interaction with normal seawater. Synthetic and natural ferrosphalerite particles used in kinetic oxidation and hydrolysis studies in seawater develop dense, crystalline coatings consisting of ordered and ferrimagnetic delta-(Fe, Zn)OOH. Due to the formation of this reactive diffusion barrier, the release of Zn into solution decreases rapidly, and sulfide oxidation is reduced to a low rate determined by the diffusion of oxygen through the oxyhydroxide film. This also acts as an efficient solvent for ions such as Zn/sup 2 +/, Ca/sup 2 +/, and possibly Cd/sup 2 +/, which contribute to the stabilization of the delta-FeOOH structure. The oxidation of sulfide occurs in many seafloor spreading areas, such as 21/sup 0/N on the East Pacific Ridge. In these areas the old surface of the sulfide chimneys are found to be covered by an orange stain, and sediment near the base of nonactive vents is also found to consist of what has been referred to as amorphous iron oxide and hydroxide. This thesis also discusses the exceedingly low solubility of zinc in seawater, from delta-(Fe, Zn)OOH and the analogous phase (zinc-ferrihydroxide) and the zinc exchange minerals, 10-A manganate and montmorillonite. The concentrations of all four are of the same magnitude (16, 36.4, and 12 nM, respectively) as the zinc concentration in deep ocean water (approx. 10 nM), which suggests that manganates and montmorillonite with iron oxyhydroxides control zinc concentration in the deep ocean.

  6. Sulfide-Driven Microbial Electrosynthesis

    SciTech Connect

    Gong, YM; Ebrahim, A; Feist, AM; Embree, M; Zhang, T; Lovley, D; Zengler, K

    2013-01-01

    Microbial electrosynthesis, the conversion of carbon dioxide to organic molecules using electricity, has recently been demonstrated for acetogenic microorganisms, such as Sporomusa ovata. The energy for reduction of carbon dioxide originates from the hydrolysis of water on the anode, requiring a sufficiently low potential. Here we evaluate the use of sulfide as an electron source for microbial electrosynthesis. Abiotically oxidation of sulfide on the anode yields two electrons. The oxidation product, elemental sulfur, can be further oxidized to sulfate by Desulfobulbus propionicus, generating six additional electrons in the process. The eight electrons generated from the combined abiotic and biotic steps were used to reduce carbon dioxide to acetate on a graphite cathode by Sporomusa ovata at a rate of 24.8 mmol/day.m(2). Using a strain of Desulfuromonas as biocatalyst on the anode resulted in an acetate production rate of 49.9 mmol/day.m(2), with a Coulombic efficiency of over 90%. These results demonstrate that sulfide can serve effectively as an alternative electron donor for microbial electrosynthesis.

  7. Interaction of H2S with Calcium Permeable Channels and Transporters

    PubMed Central

    Zhang, Weihua; Xu, Changqing; Wu, Lingyun; Wang, Rui

    2015-01-01

    A growing amount of evidence has suggested that hydrogen sulfide (H2S), as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC), T-type calcium channels (TTCC), sodium/calcium exchangers (NCX), transient receptor potential (TRP) channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR) in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms. PMID:26078804

  8. Influence of Fe doping and FeNi-layer thickness on the magnetic properties and GMI effect of electrodeposited Ni100-xFex/Cu (x = 0 95) wires

    NASA Astrophysics Data System (ADS)

    Thanh Tung, Mai; Van Dung, Nguyen; Hoang Nghi, Nguyen; Phan, Manh-Huong; Peng, Hua-Xin

    2008-05-01

    A systematic study has been performed by the influence of Fe doping and FeNi-layer thickness on the giant magnetoimpedance (GMI) effect of electrodeposited Ni100-xFex/Cu (x = 0-95) composite wires. Results obtained show that there is a correlation between the structure, soft magnetic properties and the GMI effect. Among the compositions investigated, the largest MI ratio is achieved for Ni44Fe56/Cu as a result of it having the softest magnetic property (i.e. the lowest coercivity), which arises from the smallest nanograin size. As the NiFe-layer thickness (t) increases from 1 to 27.4 µm, the GMI ratio initially increases, reaches a maximum of 110% at t = 27.4 µm and then decreases for t > 27.4 µm. Interestingly, GMI curves show a single-peak feature for wires with t < 20 µm, but a double-peak one for wires with t >= 20 µm. This indicates that there is a formation of a circular domain structure with a well-defined circumferential anisotropy in the NiFe magnetic layer of the wires with t >= 20 µm. This in turn results in a great improvement in the GMI effect of these wires.

  9. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Hydrogen sulfide. 250.504 Section 250.504... § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  10. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Hydrogen sulfide. 250.604 Section 250.604... § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  11. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Hydrogen sulfide. 250.504 Section 250.504... § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  12. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Hydrogen sulfide. 250.604 Section 250.604... § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  13. 30 CFR 250.604 - Hydrogen sulfide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Hydrogen sulfide. 250.604 Section 250.604... § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  14. 30 CFR 250.504 - Hydrogen sulfide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Hydrogen sulfide. 250.504 Section 250.504... § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown (as defined in § 250.490 of...

  15. Rapid Synthesis of Nonstoichiometric Lanthanum Sulfide

    NASA Technical Reports Server (NTRS)

    Matsuda, S.; Shapiro, E.; Danielson, L.; Hardister, H.

    1987-01-01

    New process relatively fast and simple. Improved method of synthesizing nonstoichiometric lanthanum sulfide faster and simpler. Product purer because some of prior sources of contamination eliminated.

  16. Molybdenum sulfide/carbide catalysts

    DOEpatents

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  17. Preparation of amorphous sulfide sieves

    DOEpatents

    Siadati, Mohammad H.; Alonso, Gabriel; Chianelli, Russell R.

    2006-11-07

    The present invention involves methods and compositions for synthesizing catalysts/porous materials. In some embodiments, the resulting materials are amorphous sulfide sieves that can be mass-produced for a variety of uses. In some embodiments, methods of the invention concern any suitable precursor (such as thiomolybdate salt) that is exposed to a high pressure pre-compaction, if need be. For instance, in some cases the final bulk shape (but highly porous) may be same as the original bulk shape. The compacted/uncompacted precursor is then subjected to an open-flow hot isostatic pressing, which causes the precursor to decompose and convert to a highly porous material/catalyst.

  18. Synthesis and Optical Properties of Sulfide Nanoparticles Prepared in Dimethylsulfoxide

    SciTech Connect

    Li, Yuebin; Ma, Lun; Zhang, Xing; Joly, Alan G.; Liu, Zuli; Chen, Wei

    2008-11-01

    Many methods have been reported for the formation of sulfide nanoparticles by the reaction of metallic salts with sulfide chemical sources in aqueous solutions or organic solvents. Here, we report the formation of sulfide nanoparticles in dimethylsulfoxide (DMSO) by boiling metallic salts without sulfide sources. The sulfide sources are generated from the boiling of DMSO and react with metallic salts to form sulfide nanoparticles. In this method DMSO functions as a solvent and a sulfide source as well as a stabilizer for the formation of the nanoparticles. The recipe is simple and economical making sulfide nanoparticles formed in this way readily available for many potential applications.

  19. 40 CFR 425.03 - Sulfide analytical methods and applicability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Provisions § 425.03 Sulfide analytical methods and applicability. (a) The potassium ferricyanide titration... the potassium ferricyanide titration method for the determination of sulfide in wastewaters...

  20. Response of sulfide:quinone oxidoreductase to sulfide exposure in the echiuran worm Urechis unicinctus.

    PubMed

    Ma, Yu-Bin; Zhang, Zhi-Feng; Shao, Ming-Yu; Kang, Kyoung-Ho; Shi, Xiao-Li; Dong, Ying-Ping; Li, Jin-Long

    2012-04-01

    Sulfide is a natural, widely distributed, poisonous substance, and sulfide:quinone oxidoreductase (SQR) is responsible for the initial oxidation of sulfide in mitochondria. In this study, we examined the response of SQR to sulfide exposure (25, 50, and 150 μM) at mRNA, protein, and enzyme activity levels in the body wall and hindgut of the echiuran worm Urechis unicinctus, a benthic organism living in marine sediments. The results revealed SQR mRNA expression during sulfide exposure in the body wall and hindgut increased in a time- and concentration-dependent manner that increased significantly at 12 h and continuously increased with time. At the protein level, SQR expression in the two tissues showed a time-dependent relationship that increased significantly at 12 h in 50 μM sulfide and 6 h in 150 μM, and then continued to increase with time while no significant increase appeared after 25 μM sulfide exposure. SQR enzyme activity in both tissues increased significantly in a time-dependent manner after 50 μM sulfide exposure. We concluded that SQR expression could be induced by sulfide exposure and that the two tissues studied have dissimilar sulfide metabolic patterns. A U. unicinctus sulfide-induced detoxification mechanism was also discussed. PMID:21997848

  1. Variation in sulfide tolerance of photosystem II in phylogenetically diverse cyanobacteria from sulfidic habitats

    NASA Technical Reports Server (NTRS)

    Miller, Scott R.; Bebout, Brad M.

    2004-01-01

    Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II.

  2. Variation in Sulfide Tolerance of Photosystem II in Phylogenetically Diverse Cyanobacteria from Sulfidic Habitats

    PubMed Central

    Miller, Scott R.; Bebout, Brad M.

    2004-01-01

    Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II. PMID:14766549

  3. 30 CFR 250.808 - Hydrogen sulfide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Hydrogen sulfide. 250.808 Section 250.808 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE... Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain...

  4. Catalyst and process for oxidizing hydrogen sulfide

    SciTech Connect

    Hass, R.H.; Fullerton; Ward, J.W.; Yorba, L.

    1984-04-24

    Catalysts comprising bismuth and vanadium components are highly active and stable, especially in the presence of water vapor, for oxidizing hydrogen sulfide to sulfur or SO/sub 2/. Such catalysts have been found to be especially active for the conversion of hydrogen sulfide to sulfur by reaction with oxygen or SO/sub 2/.

  5. New biologically active hydrogen sulfide donors.

    PubMed

    Roger, Thomas; Raynaud, Francoise; Bouillaud, Frédéric; Ransy, Céline; Simonet, Serge; Crespo, Christine; Bourguignon, Marie-Pierre; Villeneuve, Nicole; Vilaine, Jean-Paul; Artaud, Isabelle; Galardon, Erwan

    2013-11-25

    Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies. PMID:24115650

  6. Ammonia and hydrogen sulfide removal using biochar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  7. Weathering of sulfides on Mars

    NASA Technical Reports Server (NTRS)

    Burns, Roger G.; Fisher, Duncan S.

    1987-01-01

    Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produce degradation products in the Martian regolith. By analogy and terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni, and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato-and hydroxo-complex ions and sols formed gossan above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite), and silica (opal). Underlying groundwater, now permafrost contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates, and phyllosilicates during dust storms on Mars.

  8. Percutaneous absorption of selenium sulfide

    SciTech Connect

    Farley, J.; Skelly, E.M.; Weber, C.B.

    1986-01-01

    The purpose of this study was to determine selenium levels in the urine of Tinea patients before and after overnight application of a 2.5% selenium sulfide lotion. Selenium was measured by atomic absorption spectroscopy (AAS). Hydride generation and carbon rod atomization were studied. It was concluded from this study that selenium is absorbed through intact skin. Selenium is then excreted, at least partially, in urine, for at least a week following treatment. The data show that absorption and excretion of selenium vary on an individual basis. Selenium levels in urine following a single application of selenium sulfide lotion do not indicate that toxic amounts of selenium are being absorbed. Repeated treatments with SeS/sub 2/ result in selenium concentrations in urine which are significantly higher than normal. Significant matrix effects are observed in the carbon rod atomization of urine samples for selenium determinations, even in the presence of a matrix modifier such as nickel. The method of standard additions is required to obtain accurate results in the direct determination of selenium in urine by carbon rod AAS.

  9. Characterization of low dimensional molybdenum sulfide nanostructures

    SciTech Connect

    Camacho-Bragado, G. Alejandra; Elechiguerra, Jose Luis; Yacaman, Miguel Jose

    2008-03-15

    It is presented a detailed structural characterization of a nanostructured form of molybdenum disulfide. The material consists of a layer of highly textured molybdenum sulfide growing off a molybdenum dioxide core. The structure and chemical composition of the synthesized nanostructured sulfide was compared to two well-known forms of molybdenum disulfide, i.e. a commercial molybdenite sample and a poorly crystalline sulfide. X-ray diffraction, high-resolution electron microscopy and electron diffraction showed that the material reported here presents crystalline nanodomains with a crystal structure corresponding to the 2H polytype of molybdenum disulfide. X-ray photoelectron spectroscopy was used to demonstrate the differences between our sulfide and other materials such as amorphous MoS{sub 3}, oxysulfides and poorly crystalline MoS{sub 2}, corroborating the molybdenite-2H stacking in this form of sulfide. The material under study showed a high proportion of crystalline planes different from the basal plane.

  10. Synthesis of magnetic rhenium sulfide composite nanoparticles

    NASA Astrophysics Data System (ADS)

    Tang, Naimei; Tu, Weixia

    2009-10-01

    Rhenium sulfide nanoparticles are associated with magnetic iron oxide through coprecipitation of iron salts with tetramethylammonium hydroxide. Sizes of the formed magnetic rhenium sulfide composite particles are in the range 5.5-12.5 nm. X-ray diffraction and energy-dispersive analysis of X-rays spectra demonstrate the coexistence of Fe 3O 4 and ReS 2 in the composite particle, which confirm the formation of the magnetic rhenium sulfide composite nanoparticles. The association of rhenium sulfide with iron oxide not only keeps electronic state and composition of the rhenium sulfide nanoparticles, but also introduces magnetism with the level of 24.1 emu g -1 at 14 kOe. Surface modification with monocarboxyl-terminated poly(ethylene glycol) (MPEG-COOH) has the role of deaggregating the composite nanoparticles to be with average hydrodynamic size of 27.3 nm and improving the dispersion and the stability of the composite nanoparticles in water.