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Sample records for samarium silicides

  1. High temperature structural silicides

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  2. Synthesis of Samarium Cobalt Nanoblades

    Energy Technology Data Exchange (ETDEWEB)

    Darren M. Steele

    2010-08-25

    As new portable particle acceleration technologies become feasible the need for small high performance permanent magnets becomes critical. With particle accelerating cavities of a few microns, the photonic crystal fiber (PCF) candidate demands magnets of comparable size. To address this need, samarium cobalt (SmCo) nanoblades were attempted to be synthesized using the polyol process. Since it is preferable to have blades of 1-2 {micro}m in length, key parameters affecting size and morphology including method of stirring, reaction temperature, reaction time and addition of hydroxide were examined. Nanoparticles consisting of 70-200 nm spherical clusters with a 3-5 nm polyvinylpyrrolidone (PVP) coating were synthesized at 285 C and found to be ferromagnetic. Nanoblades of 25nm in length were observed at the surface of the nanoclusters and appeared to suggest agglomeration was occurring even with PVP employed. Morphology and size were characterized using a transmission electron microscope (TEM). Powder X-Ray Diffraction (XRD) analysis was conducted to determine composition but no supportive evidence for any particular SmCo phase has yet been observed.

  3. Silicides: Materials for thermoelectric energy conversion

    Science.gov (United States)

    Fedorov, Mikhail I.; Isachenko, Grigory N.

    2015-07-01

    There are few silicides that could be used for thermoelectric energy conversion, following higher silicides of transition metals: CrSi2, MnSi1.75, β-FeSi2, Ru2Si3, ReSi1.75, and solid solutions based on compounds of Mg2X (X = Si, Ge, and Sn). Some of them have very high figures of merit (ZT). It can be shown that, in some silicides, a high ZT is the result of energy spectrum optimization besides the decrease in thermal conductivity. This is very difficult to achieve in some materials, because the density of states is typically dependent only on the band structure of a material, for which there is no means to produce such a change. However, in solid solutions, if they have a special band structure of components, it is possible to alter the band structure to increase ZT.

  4. Synthesis and design of silicide intermetallic materials

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.; Castro, R.G.; Butt, D.P. [Los Alamos National Lab., NM (United States)] [and others

    1997-04-01

    The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive U.S. processing industries. The program presently has a number of developing industrial connections, including a CRADA with Schuller International Inc. targeted at the area of MoSi{sub 2}-based high temperature materials and components for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. Current experimental emphasis is on the development and characterization of MoSi{sub 2}-Si{sub 3}N{sub 4} and MoSi{sub 2}-SiC composites, the plasma spraying of MoSi{sub 2}-based materials, and the joining of MoSi{sub 2} materials to metals.

  5. Thermoelectric Properties of Semiconducting Silicide Nanowires

    Science.gov (United States)

    Jin, Song; Sczech, Jeannine; Higgins, Jeremy; Zhou, Feng; Shi, Li

    2008-03-01

    Semiconducting silicides are promising thermoelectric materials. In addition to their respectable thermoelectric figure-of-merit (ZT up to 0.8), silicides have the advantages of low cost, excellent thermal stability and mechanical strength, and outstanding oxidation resistance, making them suitable for high temperature applications. We have developed general synthetic approaches to single crystal nanowires of silicides to investigate the enhancement of thermoelectric properties due to the reduced nanoscale dimension and to explore their applications in thermoelectrics. We will discuss the synthesis and structural characterization of nanowires of chromium disilicide (CrSi2) prepared via a chemical vapor transport (CVT) method and chemical vapor deposition (CVD) of organometallic precursors to synthesize the Novontony Chimney ladder phase MnSi1.75. The Seebeck coefficient, electrical conductivity, and thermal conductivity of individual CrSi2 nanowires were characterized using a suspended microdevice and correlated with the structural information obtained by microscopy on the same nanowires. This combined Seebeck coefficient and electrical conductivity measurements also provide an effective approach to probing the Fermi level, carrier concentration and mobility in nanowires. We will also discuss our progress in using individual nanostructures combined well-defined structural characterization to conclusively investigate the complex thermoelectric behaviors of silicide materials.

  6. Particle-Size-Induced Valence Changes in Samarium Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Mason, M. G.; Lee, S. -T.; Apai, G.; Davis, R. F.; Shirley, D. A.; Franciosi, A.; Weaver, J. H.

    1981-09-01

    Samarium clusters exhibit mixed-valence behavior which is sensitive to particle size. XPS and UPS data show samarium to be primarily divalent (4f{sup 6} ) at small particle size. The trivalent state (4f{sup 5} ) becomes progressively more abundant with increasing s1ze, becoming the dominant state for the bulk metal. These results are interpreted using a model in which band narrowing, due to reduced surface coordination, is more dominant than surface tension effects in establishing the valence of small samarium clusters.

  7. Yellow-green electroluminescence of samarium complexes of 8-hydroxyquinoline

    Energy Technology Data Exchange (ETDEWEB)

    Behzad, Sara Karimi; Najafi, Ezzatollah [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Amini, Mostafa M., E-mail: m-pouramini@sbu.ac.ir [Department of Chemistry Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Janghouri, Mohammad; Mohajerani, Ezeddin [Laser Research Institute Shahid Beheshti University G.C., Tehran 1983963113 (Iran, Islamic Republic of); Ng, Seik Weng [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-12-15

    Four novel samarium complexes were prepared by reacting samarium(III) nitrate with 8-hydroxyquinoline, 2-methyl-8-hydroxyquinoline, and 1,10-phenanthroline and utilized as emitting materials in the electroluminescence device. All complexes were characterized by elemental analysis, infrared, UV–vis and {sup 1}H NMR spectroscopes and the molecular structure of a representative complex, [Sm{sub 2}(Me-HQ){sub 4}(NO{sub 3}){sub 6}] (1), was determined by single-crystal X-ray diffraction. Utilization of a π-conjugated (phenanthroline) ligand as a second ligand in the structure of the samarium complexes resulted in red shifts in both absorption and fluorescence spectra of complexes and moderately enhanced the photoluminescence intensity and the fluorescence quantum yield. The maximum emission peaks showed that a good correlation exists between the nature of the substituent group on the 8-hydroxyquinoline and the addition of the π-conjugated ligand in the structure of samarium complexes and emission wavelength. Devices with samarium(III) complexes with structure of ITO/PEDOT:PSS (90 nm)/PVK:PBD:Sm(III) complexes (75 nm)/Al (180 nm) were fabricated. In the electroluminescence (EL) spectra of the devices, a strong ligand-centered emission and narrow bands arising from the {sup 4}G{sub 5/2}→{sup 6}H{sub J} transitions (J=7/2, 9/2, and 11/2) of the samarium ion were observed for the complexes. The electroluminescent spectra of the samarium complexes were red-shifted as compared with the PVK:PBD blend. We believe that the electroluminescence performance of OLED devices based on samarium complexes relies on overlaps between the absorption of the samarium compounds and the emission of PVK:PBD. This revealed that it is possible to evaluate the electroluminescence performance of the samarium compounds-doped OLED devices based on the emission of PVK:PBD and the absorption of the dopants. - Highlights: • Four novel photoluminescence samarium complexes have been synthesized.

  8. Fusion silicide coatings for tantalum alloys.

    Science.gov (United States)

    Warnock, R. V.; Stetson, A. R.

    1972-01-01

    Calculation of the performance of fusion silicide coatings under simulated atmospheric reentry conditions to a maximum temperature of 1810 K (2800 F). Both recently developed and commercially available coatings are included. Data are presented on oxidation rate with and without intentional defecting, the influence of the coatings on the ductile-brittle bend transition temperature, and the mechanical properties. Coatings appear capable of affording protection for at least 100 simulated cycles to 2600 F and 63 cycles to 2800 F.

  9. Biodistribution of samarium-153-EDTMP in rats treated with docetaxel

    Energy Technology Data Exchange (ETDEWEB)

    Villarim Neto, Arthur; Acucena, Maria Kadja Meneses Torres; Pereira, Kercia Regina Santos Gomes; Rego, Amalia Cinthia Meneses [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Postgraduate Program in Health Sciences; Azevedo, Italo Medeiros; Medeiros, Aldo Cunha [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. of Surgery; Bernardo-Filho, Mario [State University of Rio de Janeiro, RJ (Brazil). Dept. of Biophysics and Biometry

    2009-01-15

    Purpose: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. Methods: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium) group received docetaxel (15 mg/kg) intraperitoneally in two cycles 11 days apart. The S (samarium/control) group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1 ml of samarium-153-EDTMP via orbital plexus (25 {mu} Ci. After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI / g) was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland). Results: On the ninth day after the administration of the second chemotherapy cycle, the rats had a significant weight loss (314.50 +- 22.09 g) compared (p<0.5) to pre-treatment weight (353.66 {+-} 22.8). The % ATI/g in the samples of rats treated with samarium-153-EDTMP had a significant reduction in the right femur, left femur, kidney, liver and lungs of animals treated with docetaxel, compared to the control rats. Conclusion: The combination of docetaxel and samarium-153-EDTMP was associated with a lower response rate in the biodistribution of the radiopharmaceutical to targeted tissues. Further investigation into the impact of docetaxel on biodistribution of samarium-153-EDTMP would complement the findings of this study. (author)

  10. Fabrication and Gas-Sensing Properties of Ni-Silicide/Si Nanowires

    OpenAIRE

    Hsu, Hsun-Feng; Chen, Chun-An; Liu, Shang-Wu; Tang, Chun-Kai

    2017-01-01

    Ni-silicide/Si nanowires were fabricated by atomic force microscope nano-oxidation on silicon-on-insulator substrates, selective wet etching, and reactive deposition epitaxy. Ni-silicide nanocrystal-modified Si nanowire and Ni-silicide/Si heterostructure multi-stacked nanowire were formed by low- and high-coverage depositions of Ni, respectively. The Ni-silicide/Si Schottky junction and Ni-silicide region were attributed high- and low-resistance parts of nanowire, respectively, causing the re...

  11. The Basis for Developing Samarium AMS for Fuel Cycle Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A; Biegalski, S R; Whitney, S M; Tumey, S J; Weaver, C J

    2008-10-13

    Modeling of nuclear reactor fuel burnup indicates that the production of samarium isotopes can vary significantly with reactor type and fuel cycle. The isotopic concentrations of {sup 146}Sm, {sup 149}Sm, and {sup 151}Sm are potential signatures of fuel reprocessing, if analytical techniques can overcome the inherent challenges of lanthanide chemistry, isobaric interferences, and mass/charge interferences. We review the current limitations in measurement of the target samarium isotopes and describe potential approaches for developing Sm-AMS. AMS sample form and preparation chemistry will be discussed as well as possible spectrometer operating conditions.

  12. Thermoelectric properties of group VI metal silicide semiconductors

    Science.gov (United States)

    Nonomura, T.; Wen, C.; Kato, A.; Isobe, K.; Kubota, Y.; Nakamura, T.; Yamashita, M.; Hayakawa, Y.; Tatsuoka, H.

    The electrical and thermoelectric properties of group VI metal silicides, such as the Mo- and W-silicides as well as CrSi2, were investigated. The electronic band structures of the hexagonal- MoSi2, - WSi2 and CrSi2, were calculated using the first-principles total-energy calculation program in pseudopotential schemes with plane-wave basis functions, and their Seebeck coefficients were also calculated. In addition, the Mo- and W-silicides were synthesized using mechanical alloying followed by a spark plasma sintering technique, and their structural, electric and thermoelectric properties were examined.

  13. Optical characteristics of transparent samarium oxide thin films ...

    Indian Academy of Sciences (India)

    Optical characteristics of transparent samarium oxide thin films deposited by the radio-frequency sputtering technique. A A ATTA M M EL-NAHASS KHALED M ELSABAWY M M ABD EL-RAHEEM A M HASSANIEN A ALHUTHALI ALI BADAWI AMAR MERAZGA. Regular Volume 87 Issue 5 November 2016 Article ID 72 ...

  14. Optical properties of zinc–vanadium glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3() ZnO(40-)V2O5(60) (where = 0.1–0.5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been calculated.

  15. Optical properties of samarium doped zinc–tellurite glasses

    Indian Academy of Sciences (India)

    Unknown

    Optical properties of samarium doped zinc–tellurite glasses. B ERAIAH. Department of Physics, Karnatak University, Dharwad 580 003, India. Present address: Department of Physics, Bangalore University, Bangalore 560 056, India. MS received 20 March 2006; revised 13 June 2006. Abstract. Glasses with the composition, ...

  16. Effect of second ligand on the luminescence of Samarium (III ...

    Indian Academy of Sciences (India)

    Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: Syntheses, crystal structures, thermal analysis and luminescence study. MUHAMMAD IDIRIS SALEH, MIN YEE CHOO, TAI WEI CHAN and MOHD R RAZALI. ∗. School of Chemical Sciences, Universiti Sains Malaysia, Penang, ...

  17. Effect of second ligand on the luminescence of Samarium (III ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 12. Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: ... Muhammad Idiris Saleh1 Min Yee Choo1 Tai Wei Chan1 Mohd R Razali1. School of Chemical Sciences, Universiti Sains Malaysia, Penang, Malaysia ...

  18. Rare earth silicide nanowires on silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Martina

    2008-11-10

    The growth, structure and electronic properties of rare earth silicide nanowires are investigated on planar and vicinal Si(001) und Si(111) surfaces with scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). On all surfaces investigated within this work hexagonal disilicides are grown epitaxially with a lattice mismatch of -2.55% up to +0.83% along the hexagonal a-axis. Along the hexagonal c-axis the lattice mismatch is essentially larger with 6.5%. On the Si(001)2 x 1 surface two types of nanowires are grown epitaxially. The socalled broad wires show a one-dimensional metallic valence band structure with states crossing the Fermi level. Along the nanowires two strongly dispersing states at the anti J point and a strongly dispersing state at the anti {gamma} point can be observed. Along the thin nanowires dispersing states could not be observed. Merely in the direction perpendicular to the wires an intensity variation could be observed, which corresponds to the observed spacial structure of the thin nanowires. The electronic properties of the broad erbium silicide nanowires are very similar to the broad dysprosium silicide nanowires. The electronic properties of the DySi{sub 2}-monolayer and the Dy{sub 3}Si{sub 5}-multilayer on the Si(111) surface are investigated in comparison to the known ErSi{sub 2}/Si(111) and Er{sub 3}Si{sub 5}/Si(111) system. The positions and the energetic locations of the observed band in the surface Brillouin zone will be confirmed for dysprosium. The shape of the electron pockets in the (vector)k {sub parallel} space is elliptical at the anti M points, while the hole pocket at the anti {gamma} point is showing a hexagonal symmetry. On the Si(557) surface the structural and electronic properties depend strongly on the different preparation conditions likewise, in particular on the rare earth coverage. At submonolayer coverage the thin nanowires grow in wide areas

  19. Dependence of samarium-soil interaction on samarium concentration: Implications for environmental risk assessment.

    Science.gov (United States)

    Ramírez-Guinart, Oriol; Salaberria, Aitor; Vidal, Miquel; Rigol, Anna

    2018-03-01

    The sorption and desorption behaviour of samarium (Sm), an emerging contaminant, was examined in soil samples at varying Sm concentrations. The obtained sorption and desorption parameters revealed that soil possessed a high Sm retention capacity (sorption was higher than 99% and desorption lower than 2%) at low Sm concentrations, whereas at high Sm concentrations, the sorption-desorption behaviour varied among the soil samples tested. The fractionation of the Sm sorbed in soils, obtained by sequential extractions, allowed to suggest the soil properties (pH and organic matter solubility) and phases (organic matter, carbonates and clay minerals) governing the Sm-soil interaction. The sorption models constructed in the present work along with the sorption behaviour of Sm explained in terms of soil main characteristics will allow properly assessing the Sm-soil interaction depending on the contamination scenario under study. Moreover, the sorption and desorption K d values of radiosamarium in soils were strongly correlated with those of stable Sm at low concentrations (r = 0.98); indicating that the mobility of Sm radioisotopes and, thus, the risk of radioactive Sm contamination can be predicted using data from low concentrations of stable Sm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Evaluation of Transmission Line Model Structures for Silicide-to-Silicon Specific Contact Resistance Extraction

    NARCIS (Netherlands)

    Stavitski, N.; van Dal, Mark J.H.; Lauwers, Anne; Vrancken, Christa; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2008-01-01

    In order to measure silicide-to-silicon specific contact resistance �?c, transmission line model (TLM) structures were proposed as attractive candidates for embedding in CMOS processes. We optimized TLM structures for nickel silicide and platinum silicide and evaluated them for various doping levels

  1. Mechanism of the electrochemical deposition of samarium-based coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Edgar J. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Ortega-Borges, Raul [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Godinez, Luis A. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Chapman, Thomas W. [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico); Meas-Vong, Yunny [Electrochemistry Department, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76700 Queretaro (Mexico)]. E-mail: yunnymeas@cideteq.mx

    2006-11-12

    Samarium-based films have been shown to form from aqueous solutions on the surfaces of metallic substrates such as steel or aluminum, and their presence has been reported to decrease substantially the corresponding corrosion rate of the underlying metallic substrate. Based on previous reports on the deposition of oxides or hydroxides of the closely related element cerium, this work demonstrates that samarium films are formed following a similar mechanism, which involves as the fundamental step an increase in interfacial pH resulting from cathodic oxygen-reduction or hydrogen-evolution reactions. With cyclic voltammetry (CV), electrochemical quartz-crystal microbalance (EQCM) measurements, rotating-disk electrode (RDE) tests, and surface characterization techniques, namely, scanning electron microscopy (SEM) and X-ray surface microanalysis (EDX), the postulated mechanism was verified, and the surface morphology of the resulting films was correlated with the nature of the reduction reaction that triggers film formation.

  2. Samarium Monosulfide (SmS): Reviewing Properties and Applications

    OpenAIRE

    Sousanis, Andreas; Smet, Philippe; Poelman, Dirk

    2017-01-01

    In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducti...

  3. Optical properties of zinc–vanadium glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Abstract. Zinc–vanadium glasses doped with samarium oxide having the chemical composition Sm2O3(x). ZnO(40−x)V2O5(60)(where x = 0·1–0·5 mol%) were prepared by melt quenching method. The density of these glasses was measured by Archimedes method; the corresponding molar volumes have also been ...

  4. Synthesis of nano-pore samarium (III)-imprinted polymer for preconcentrative separation of samarium ions from other lanthanide ions via solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Shirvani-Arani, Simindokht [Center of Excellence in Electrochemistry, Department of Chemistry, University of Tehran, P.O.Box:14155-6455, Tehran (Iran, Islamic Republic of); Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Ahmadi, Seyed Javad [Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)], E-mail: sjahmadi@aeoi.org.ir; Bahrami-Samani, Ali [Nuclear Engineering and Physics Department, Amir Kabir University, P.O.Box: 15875-4413, Tehran (Iran, Islamic Republic of); Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Ghannadi-Maragheh, Mohammad [Jaber Ibne Hayan Research Laboratories, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)

    2008-08-08

    A batch process was developed to separate samarium ions from some lanthanide ions by a novel solid phase which was prepared via the ion-imprinting technique. The samarium (III) ion-imprinted polymer (IIP) particles were synthesized by preparing the ternary complex of samarium ions with 5,7-dichloroquinoline-8-ol (DCQ) and 4-vinylpyridine (VP). Then, thermally copolymerization with styrene (functional monomer, STY) and divinylbenzene (cross-linking monomer, DVB) followed in the presence of 2-methoxy ethanol (porogen) and 2,2'-azobisisobutyronitrile (initiator, AIBN). The imprinted ion was removed by stirring the above particles with 50% (v/v) HCl to obtain the leached IIP particles. Moreover, control polymer (CP) particles were similarly prepared without the samarium ions. The unleached and leached IIP particles were characterized by X-ray diffraction (XRD), infra-red spectroscopy (IR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). Finally, preconcentration and selectivity studies for samarium and the other lanthanide ions were carried out. The preconcentration of the samarium (III) traces was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the preconcentration and the elution times, the eluent volume and the aqueous phase volume. These studies indicated that the samarium (III) amount as low as 1 {mu}g, present in 200 mL, could be preconcentrated into 25 mL of 1.0 M HCl.

  5. Anomalous frequency dependent diamagnetism in metal silicide

    Science.gov (United States)

    Dahal, Ashutosh; Gunasekera, Jagat; Harriger, Leland; Singh, David J.; Singh, Deepak K.; Leland Harriger Collaboration

    Discovery of superconductivity in PbO-type FeSe has generated a lot of interest. Among the samples we synthesize with similar structure, NiSi has showed anomalous but very interesting results. Nickel silicides are important electronic materials that have been used as contacts for field effect transistors, as interconnects and in nanoelectronic devices. The magnetic properties of NiSi are not well known, however. In this presentation, we report a highly unusual magnetic phenomenon in NiSi. The ac susceptibility measurements on NiSi reveal strong frequency dependence of static and dynamic susceptibilities that are primarily diamagnetic at room temperature. The static susceptibility is found to exhibit a strong frequency dependence of the diamagnetic response below 100K, while dynamic susceptibility showed peak type feature at 10KHz frequency around 50K. Detailed neutron scattering measurements on high quality powder sample of NiSi on SPINS cold spectrometer further revealed an inelastic peak around 1.5meV, even though no magnetic order is detected. The inelastic peak dissipates above 100K, which is where the static susceptibility starts to diverge with frequency. Research is supported by U.S. Department of Energy, Office of Basic Energy Sciences under Grant No. DE-SC0014461.

  6. Submicron Features in Higher Manganese Silicide

    Directory of Open Access Journals (Sweden)

    Yatir Sadia

    2013-01-01

    Full Text Available The world energy crisis had increased the demand for alternative energy sources and as such is one of the topics at the forefront of research. One way for reducing energy consumption is by thermoelectricity. Thermoelectric effects enable direct conversion of thermal into electrical energy. Higher manganese silicide (HMS, MnSi1.75 is one of the promising materials for applications in the field of thermoelectricity. The abundance and low cost of the elements, combined with good thermoelectric properties and high mechanical and chemical stability at high temperatures, make it very attractive for thermoelectric applications. Recent studies have shown that Si-rich HMS has improved thermoelectric properties. The most interesting of which is the unusual reduction in thermal conductivity. In the current research, transmission (TEM and scanning (SEM electron microscopy as well as X-ray diffraction methods were applied for investigation of the govern mechanisms resulting in very low thermal conductivity values of an Si-rich HMS composition, following arc melting and hot-pressing procedures. In this paper, it is shown that there is a presence of sub-micron dislocations walls, stacking faults, and silicon and HMS precipitates inside each other apparent in the matrix, following a high temperature (0.9 Tm hot pressing for an hour. These are not just responsible for the low thermal conductivity values observed but also indicate the ability to create complicate nano-structures that will last during the production process and possibly during the application.

  7. Si-Ge Nano-Structured with Tungsten Silicide Inclusions

    Science.gov (United States)

    Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

    2014-01-01

    Traditional silicon germanium high temperature thermoelectrics have potential for improvements in figure of merit via nano-structuring with a silicide phase. A second phase of nano-sized silicides can theoretically reduce the lattice component of thermal conductivity without significantly reducing the electrical conductivity. However, experimentally achieving such improvements in line with the theory is complicated by factors such as control of silicide size during sintering, dopant segregation, matrix homogeneity, and sintering kinetics. Samples are prepared using powder metallurgy techniques; including mechanochemical alloying via ball milling and spark plasma sintering for densification. In addition to microstructural development, thermal stability of thermoelectric transport properties are reported, as well as couple and device level characterization.

  8. Formation of cobalt silicide by ion beam mixing

    Science.gov (United States)

    Min, Ye; Burte, Edmund P.; Ryssel, Heiner

    1991-07-01

    The formation of cobalt silicides by arsenic ion implantation through a cobalt film which causes a mixing of the metal with the silicon substrate was investigated. Furthermore, cobalt suicides were formed by rapid thermal annealing (RTA). Sheet resistance and silicide phases of implanted Co/Si samples depend on the As dose. Ion beam mixing at doses higher than 5 × 10 15 cm -2 and RTA at temperatures T ⩾ 900° C result in almost equal values of Rs. RBS and XRD spectra of these samples illustrate the formation of a homogeneous CoSi 2 layer. Significant lateral growth of cobalt silicide beyond the edge of patterned SiO 2 was observed in samples which were only subjected to an RTA process ( T ⩾ 900 ° C), while this lateral suicide growth could be reduced efficiently by As implantation prior to RTA.

  9. Ultra Thin Poly-Si Nanosheet Junctionless Field-Effect Transistor with Nickel Silicide Contact.

    Science.gov (United States)

    Lin, Yu-Ru; Tsai, Wan-Ting; Wu, Yung-Chun; Lin, Yu-Hsien

    2017-11-07

    This study demonstrated an ultra thin poly-Si junctionless nanosheet field-effect transistor (JL NS-FET) with nickel silicide contact. For the nickel silicide film, two-step annealing and a Ti capping layer were adopted to form an ultra thin uniform nickel silicide film with low sheet resistance (Rs). The JL NS-FET with nickel silicide contact exhibited favorable electrical properties, including a high driving current (>10⁷A), subthreshold slope (186 mV/dec.), and low parasitic resistance. In addition, this study compared the electrical characteristics of JL NS-FETs with and without nickel silicide contact.

  10. Ultra Thin Poly-Si Nanosheet Junctionless Field-Effect Transistor with Nickel Silicide Contact

    Directory of Open Access Journals (Sweden)

    Yu-Ru Lin

    2017-11-01

    Full Text Available This study demonstrated an ultra thin poly-Si junctionless nanosheet field-effect transistor (JL NS-FET with nickel silicide contact. For the nickel silicide film, two-step annealing and a Ti capping layer were adopted to form an ultra thin uniform nickel silicide film with low sheet resistance (Rs. The JL NS-FET with nickel silicide contact exhibited favorable electrical properties, including a high driving current (>107A, subthreshold slope (186 mV/dec., and low parasitic resistance. In addition, this study compared the electrical characteristics of JL NS-FETs with and without nickel silicide contact.

  11. Silicide Schottky Contacts to Silicon: Screened Pinning at Defect Levels

    Energy Technology Data Exchange (ETDEWEB)

    Drummond, T.J.

    1999-03-11

    Silicide Schottky contacts can be as large as 0.955 eV (E{sub v} + 0.165 eV) on n-type silicon and as large as 1.05 eV (E{sub c} {minus} 0.07 eV) on p-type silicon. Current models of Schottky barrier formation do not provide a satisfactory explanation of occurrence of this wide variation. A model for understanding Schottky contacts via screened pinning at defect levels is presented. In the present paper it is shown that most transition metal silicides are pinned approximately 0.48 eV above the valence band by interstitial Si clusters. Rare earth disilicides pin close to the divacancy acceptor level 0.41 eV below the conduction band edge while high work function silicides of Ir and Pt pin close to the divacancy donor level 0.21 eV above the valence band edge. Selection of a particular defect pinning level depends strongly on the relative positions of the silicide work function and the defect energy level on an absolute energy scale.

  12. Silicon and silicide nanowires applications, fabrication, and properties

    CERN Document Server

    Tu, King-Ning

    2013-01-01

    This book comprises theoretical and experimental analysis of various properties of silicon nanocrystals, research methods and preparation techniques, and some promising applications. It comprises nine chapters. The first three are based on processing, the next three on properties, and the last three on applications of nanowires of silicon and silicides.

  13. Spin, Charge, and Bonding in Transition Metal Mono Silicides

    NARCIS (Netherlands)

    Marel, D. van der; Damascelli, A.; Schulte, K.; Menovsky, A. A.

    1997-01-01

    Published in: Physica B 244 (1998) 138-147 citations recorded in [Science Citation Index] Abstract: We review some of the relevant physical properties of the transition metal mono-silicides with the FeSi structure (CrSi, MnSi, FeSi, CoSi, NiSi, etc) and explore the relation between their structural

  14. Ionization of Samarium by Chemical Releases in the Upper Atmosphere

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.; Holmes, J. M.; Pedersen, T. R.; Caton, R.; Miller, D.; Groves, K. M.

    2014-12-01

    The release of Samarium vapor into the upper atmosphere was studied using during the Air Force Research Laboratory sponsored Metal Oxide Space Cloud (MOSC) rocket launches in May 2009. The Naval Research Laboratory supported these experiments with 3-D photochemical modeling of the artificial plasma cloud including (1) reactions with atomic oxygen, (2) photo excitation, (3) photoionization, (4) dissociative recombination, and (5) ion and neutral diffusion. NRL provided the experimental diagnostic instrument on the rocket which was a dual frequency radio beacon on the rocket to measure changes in total electron content. The AFRL provided ground based diagnostics of incoherent scatter radar and optical spectroscopy and imagery. The NRL Chemical Release Model (CRM) has over 600 excited states of atomic Samarium neutrals, atomic ions, along with Samarium Oxide Ions and electrons. Diffusive transport of neutrals in cylindrical geometry and ions along magnetic field lines is computed along with the reactive flow to predict the concentrations of Sm, Sm-Ion, Sm0, and SmO Ion. Comparison of the CRM with observations demonstrates that Sm release into the upper atmosphere initially produces enhanced electron densities and SmO-Ions. The diatomic ions recombine with electrons to yield neutral Sm and O. Only the photo ionization of Sm yields a stable atomic ion that does not substantially recombine. The MOSC releases in sunlight yielded long duration ion clouds that can be replicated with the CRM. The CRM predicts that Sm releases in darkness would not produce long duration plasma clouds because of the lack of photo excitation and photoionization.

  15. Reactive Materials for Evaporating Samarium (Pre-Print)

    Science.gov (United States)

    2016-04-15

    SUBJECT TERMS energetic materials, heat sources, pyrotechnic charges, easily ionized metals 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...experiments.    Keywords:  energetic  materials, heat sources, pyrotechnic charges, easily ionized metals  1. Introduction Ejection of clouds of...results  were  negatively  affected  by  reduced  efficiency   of  release  and  ionization of samarium [8]. It is possible that not the entire charge of

  16. Texture in thin film silicides and germanides: A review

    Energy Technology Data Exchange (ETDEWEB)

    De Schutter, B., E-mail: bob.deschutter@ugent.be; De Keyser, K.; Detavernier, C. [Department of Solid State Sciences, Ghent University, Ghent (Belgium); Lavoie, C. [IBM Research Division, T.J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (United States)

    2016-09-15

    Silicides and germanides are compounds consisting of a metal and silicon or germanium. In the microelectronics industry, silicides are the material of choice for contacting silicon based devices (over the years, CoSi{sub 2}, C54-TiSi{sub 2}, and NiSi have been adopted), while germanides are considered as a top candidate for contacting future germanium based electronics. Since also strain engineering through the use of Si{sub 1−x}Ge{sub x} in the source/drain/gate regions of MOSFET devices is an important technique for improving device characteristics in modern Si-based microelectronics industry, a profound understanding of the formation of silicide/germanide contacts to silicon and germanium is of utmost importance. The crystallographic texture of these films, which is defined as the statistical distribution of the orientation of the grains in the film, has been the subject of scientific studies since the 1970s. Different types of texture like epitaxy, axiotaxy, fiber, or combinations thereof have been observed in such films. In recent years, it has become increasingly clear that film texture can have a profound influence on the formation and stability of silicide/germanide contacts, as it controls the type and orientation of grain boundaries (affecting diffusion and agglomeration) and the interface energy (affecting nucleation during the solid-state reaction). Furthermore, the texture also has an impact on the electrical characteristics of the contact, as the orientation and size of individual grains influences functional properties such as contact resistance and sheet resistance and will induce local variations in strain and Schottky barrier height. This review aims to give a comprehensive overview of the scientific work that has been published in the field of texture studies on thin film silicide/germanide contacts.

  17. Nanoscale contact engineering for Silicon/Silicide nanowire devices

    Science.gov (United States)

    Lin, Yung-Chen

    Metal silicides have been used in silicon technology as contacts to achieve high device performance and desired device functions. The growth and applications of silicide materials have recently attracted increasing interest for nanoscale device applications. Nanoscale silicide materials have been demonstrated with various synthetic approaches. Solid state reaction wherein high quality silicides form through diffusion of metal atoms into silicon nano-templates and the subsequent phase transformation caught significant attention for the fabrication of nanoscale Si devices. Very interestingly, studies on the diffusion and phase transformation processes at nanoscale have indicated possible deviations from the bulk and the thin film system. Here we studied growth kinetics, electronic properties and device applications of nanoscale silicides formed through solid state reaction. We have grown single crystal PtSi nanowires and PtSi/Si/PtSi nanowire heterostructures through solid state reaction. TEM studies show that the heterostructures have atomically sharp interfaces free of defects. Electrical measurement of PtSi nanowires shows a low resistivity of ˜28.6 μΩ·cm and a high breakdown current density beyond 108 A/cm2. Furthermore, using single-crystal PtSi/Si/PtSi nanowire heterostructures with atomically clean interfaces, we have fabricated p-channel enhancement mode transistors with the best reported performance for intrinsic silicon nanowires to date. In our results, silicide can provide a clean and no Fermi level pinning interface and then silicide can form Ohmic-contact behavior by replacing the source/drain metal with PtSi. It has been proven by our experiment by contacting PtSi with intrinsic Si nanowires (no extrinsic doping) to achieve high performance p-channel device. By utilizing the same approach, single crystal MnSi nanowires and MnSi/Si/MnSi nanowire heterojunction with atomically sharp interfaces can also been grown. Electrical transport studies on Mn

  18. Implementation of an analytical technique for Samarium; Implementacion de una tecnica analitica para Samario

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)

    2004-07-01

    Since the Samarium presents the same chemical properties that the plutonium, it has been used as homologous in studies that allow us to know the behavior that the plutonium presents in solution, with the advantage of working with an inactive and not very dangerous element. At the moment studies of sorption of plutonium or samarium are made on some mineral matrices that present certain surface properties. Due to the low concentrations that are used in the studies of sorption of samarium on those reagent substrates, their detection becomes very difficult for the conventional analysis media. The luminescence is a technique that can detect lower concentrations, smaller at 1 X 10{sup -} {sup 2} M, but when fluorofors are used this limit of detection increases in several orders of magnitude. In this work it has been used the arsenazo-III as fluorofor agent since it reacts in a specific way with the samarium, forming a complex that presents a proportional luminescence to the concentration of the present samarium. The advantage of making the quantification of samarium by luminescence is that it can use the same instrumental equipment to determine the speciation of the samarium sipped in the zircon. (Author)

  19. Synthesis of samarium binding bleomycin - a possible NCT radiosensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, B.M., E-mail: bmm@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Mendes, T.M.; Campos, T.P.R., E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Bleomycin (BLM) is a drug that has attractive features for the development of a new radiopharmaceutical, particularly with regard to neutron capture therapy (NCT) sensitized by Sm-149. It has the ability to chelate many metal ions. In vitro studies have shown that up to 78% of BLM present in a cell is accumulated inside the nucleus or in the nuclear membrane. In addition, this drug has higher affinity for tumor tissues than for normal tissues. Radioactive isotopes carried by this antibiotic would be taken preferentially to one important cellular targets DNA. Besides, BLM displays intrinsic anti-tumor activity - it is a chemotherapic antibiotic clinically used against some cancers. This study aimed to obtain bleomycin molecules bound to samarium (BLM-Sm) for NCT studies in vitro and in vivo. The binding technique employed in this work has great simplicity and low cost. Thin layer chromatography, high performance liquid chromatography, fast protein liquid chromatography and analysis by ICP-AES were applied to verify the binding molecule. ICP-AES results showed the presence of samarium in the sample peaks related to BLM-Sm. However, efficiency and stability of this bond needs to be investigated. (author)

  20. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  1. Electronic properties of semiconducting silicides: fundamentals and recent predictions

    Energy Technology Data Exchange (ETDEWEB)

    Ivanenko, L.I.; Shaposhnikov, V.L.; Filonov, A.B.; Krivosheeva, A.V.; Borisenko, V.E.; Migas, D.B.; Miglio, L.; Behr, G.; Schumann, J

    2004-08-02

    This review emphasizes progress in theoretical simulation and experiments that have been performed in the past years for semiconducting silicides. New fundamental electronic and optical properties of Ca{sub 2}Si and BaSi{sub 2}, recently found RuSi{sub 2} phase, ternaries in Fe-Os-Si and Ru-Os-Si systems, {beta}-FeSi{sub 2}, Mg{sub 2}Si and CrSi{sub 2} with stretched and compressed lattices as well as transport properties of {beta}-FeSi{sub 2}, ReSi{sub 1.75}, Ru{sub 2}Si{sub 3} are presented. Prospects for practical applications of semiconducting silicides are discussed.

  2. Reactive growth of niobium silicides in bulk diffusion couples

    Energy Technology Data Exchange (ETDEWEB)

    Milanese, Chiara; Buscaglia, Vincenzo; Maglia, Filippo; Anselmi-Tamburini, Umberto

    2003-09-15

    The diffusion-controlled growth of niobium silicides (NbSi{sub 2} and Nb{sub 5}Si{sub 3}) was studied in Nb/Si and Nb/NbSi{sub 2} bulk diffusion couples annealed at 1200-1350 degree sign C for 2-24 h. Both compounds were found to grow as parallel layers, according to the parabolic rate law. The concept of the integrated diffusion coefficient is used to describe the growth kinetics of the two silicides. The corresponding activation energy is 263 kJ/mol for Nb{sub 5}Si{sub 3} and 304 kJ/mol for NbSi{sub 2}. The activation energy (in eV) scales as 0.98T{sub m}(K)/1000 for Nb{sub 5}Si{sub 3} and as 1.4T{sub m}(K)/1000 for NbSi{sub 2} in agreement with the general behavior observed for many transition metal silicides. The position of the Kirkendall plane inside the Nb{sub 5}Si{sub 3} layer developed in Nb/NbSi{sub 2} couples indicates that, in the present temperature range, the diffusion of Si in Nb{sub 5}Si{sub 3} is considerably faster than that of Nb.

  3. Syntheses of Nanostructure Bundles Based on Semiconducting Metal Silicides

    Science.gov (United States)

    Li, Wen; Ishikawa, Daisuke; Tatsuoka, Hirokazu

    2013-08-01

    A variety of nanostructure bundles and arrays based on semiconducting metal silicides have been synthesized using abundant and non-toxic starting materials. Three types of fabrication techniques of the nanostructure bundles or arrays, including direct growth, template synthesis using natural nanostructured materials and template synthesis using artificially fabricated nanostructured materials are demonstrated. CrSi2 nanowire bundles were directly grown by the exposure of Si substrates to CrCl2 vapor at atmospheric pressure. A hexagonal MoSi2 nanosheet, Mg2Si/MgO composite nanowire and Mg2Si nanowire bundles and MnSi1.7 nanowire array were synthesized using a MoS2 layered material, a SiOx nanofiber bundle, a Si nanowire array, and a Si nanowire array as the templates, respectively. Additionally, the fabrication phenomenon and structural properties of the nanostructured semiconducting metal silicides were investigated. These reactions provided the low-cost and controllable synthetic techniques to synthesize large scale and one-dimensional semiconducting metal silicides for thermoelectric applications.

  4. Luminescent solutions and powders of new samarium complexes with N,N',O,O'-chelating ligands

    Science.gov (United States)

    Kharcheva, Anastasia V.; Nikolskiy, Kirill S.; Borisova, Nataliya E.; Ivanov, Alexey V.; Reshetova, Marina D.; Yuzhakov, Viktor I.; Patsaeva, Svetlana V.

    2016-04-01

    Imaging techniques in biology and medicine are crucial tools to obtain information on structural and functional properties of living cells and organisms. To fulfill the requirements associated with application of these techniques it appears necessary to design markers with specific characteristics. Luminescent complexes of trivalent lanthanide ions with chelating ligands are of increasing importance in biomedical applications because of their millisecond luminescence lifetime, narrow emission band, high signal-to-noise ratio and minimal photodamage to biological samples. In order to extend the available emission wavelength range the luminescent samarium chelates are highly desirable. In this study the ligands with diamides of 2,2'-bipyridin-6,6'-dicarboxylic acid were used to improve photophysical characteristics of samarium complexes. We report the luminescence characteristics of samarium complexes with novel ligands. All complexes exhibited the characteristic emission of Sm (III) ion with the lines at 565, 597, 605, 645 and 654 nm, the intensity strongly depended on the ligand. Absorption and luminescence excitation spectra of Sm (III) complexes showed main peaks in the UV range demonstrating lanthanide coordination to the ligand. The absolute lumenescence quantum yield was measured for solutions in acetonitrile with excitation at 350 nm. The largest luminescence quantum yield was found for the samarium complex Bipy 6MePy Sm (3%) being much higher that for samarium complexes reported in the literature earlier. These results prove as well that samarium chelates are potential markers for multiparametric imaging techniques.

  5. Australian manufacture of Quadramet{sup TM} (Samarium-153 EDTMP)

    Energy Technology Data Exchange (ETDEWEB)

    Wood, N.R.; Whitwell, J. [Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW (Australia). Australian Radioisotopes

    1997-10-01

    Quadramet{sup T} (Samarium-153 EDTMP) has been shown overseas to be potentially useful in the palliation of painful osteoblastic skeletal metastases and has been approved this year for general marketing in the USA. Australian Radioisotopes (ARI) has licensed this product from the Australian patent holders, Dow Chemical. Within the facilities of ARI, a hot cell has been dedicated to this product and fitted out to manufacture it weekly on a cycle related to the operating cycle of the Australian reactor HIFAR. Due to neutron flux limitations of HIFAR, the local formulation has an elemental Samarium content up to 200{mu}g/mL whereas the overseas formulation has a level of 20-46{mu}g/mL. All other specifications of the two products are essentially the same. In 1995 and 1996 a small clinical trial with 19 patients was held which demonstrated that the pharmacokinetic behaviour was also essentially the same by measuring blood clearance rates and skeletal uptake dynamics. Soft tissue uptake was also qualitatively determined. The ARI version is now the subject of an application for general marketing within Australia. Some useful characteristics of this agent are: almost complete excretion or fixation in the skeleton within 6 hours, rapid onset of clinical effect, applicability in most cases where an abnormal diagnostic bone scan correlates with painful sites, dosage can be tailored to individual patient uptake due to easy dose measurement and retreatment is quite possible. The use of this class of agents in pain palliation continues to increase. Australian manufacture of Quadramet{sup TM} provides a further option in the management of these difficult cases

  6. Electrochemical extraction of samarium from molten chlorides in pyrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Castrillejo, Y., E-mail: ycastril@qa.uva.es [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Fernandez, P. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Medina, J. [Dept Fisica Materia Condensada Cristalografia y Mineralogia, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain); Hernandez, P. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo, Carr. Pachuca-Tulancingo Km. 4.5, C.P. 42076 Pachuca, Hidalgo (Mexico); Barrado, E. [QUIANE/Dept Quimica Analitica, F. de Ciencias, Universidad de Valladolid, Prado de la Magdalena s/n, 47005 Valladolid (Spain)

    2011-10-01

    This work concerns the electrochemical extraction of samarium from molten chlorides. In this way, the electrochemical behaviour of samarium ions has been investigated in the eutectic LiCl-KCl at the surface of tungsten, aluminium and aluminium coated tungsten electrodes. On a W inert electrode the electro-reduction of Sm(III) takes place in only one soluble-soluble electrochemical step Sm(III)/Sm(II). The electrochemical system Sm(II)/Sm(0) has not been observed within the electrochemical window, because of the prior reduction of Li(I) ions from the solvent, which inhibits the electro-extraction of Sm species from the salt on such a substrate. Sm metal in contact with the melt react to give Li(0) according to the reaction: Sm(0) + 2Li(I) {r_reversible} Sm(II) + 2Li(0). On the contrary, on reactive Al electrodes the electrochemical system Sm(II)/Sm(0) was observed within the electroactive range. The potential shift of the redox couple is caused by the decrease of Sm activity in the metal phase due to the formation of Sm-Al alloys at the interface. The formation mechanism of the intermetallic compounds was studied in a melt containing: (i) both Sm(III) and Al(III) ions, using W and Al coated tungsten electrodes, and (ii) Sm(III) ions using an Al electrode. Analysis of the samples after potentiostatic electrolysis by X-ray diffraction and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), allowed the identification of Al{sub 3}Sm and Al{sub 2}Sm.

  7. Mechanoactivation of chromium silicide formation in the SiC-Cr-Si system

    Directory of Open Access Journals (Sweden)

    Vlasova M.

    2002-01-01

    Full Text Available The processes of simultaneous grinding of the components of a SiC-Cr-Si mixture and further temperature treatment in the temperature range 1073-1793 K were studied by X-ray phase analysis, IR spectroscopy, electron microscopy, and X-ray microanalysis. It was established that, during grinding of the mixture, chromium silicides form. A temperature treatment completes the process. Silicide formation proceeds within the framework of the diffusion of silicon into chromium. In the presence of SiO2 in the mixture, silicide formation occurs also as a result of the reduction of silica by silicon and silicon carbide. The sintering of synthesized composite SiC-chromium silicides powders at a high temperature under a high pressure (T = 2073 K, P = 5 GPa is accompanied by the destruction of cc-SiC particles, the cc/3 transition in silicon carbide and deformation distortions of the lattices of chromium silicides.

  8. Oxidation behavior of multiphase molybdenum-molybdenum silicide-molybdenum silicide boride intermetallics

    Science.gov (United States)

    Dheeradhada, Voramon Supatarawanich

    Multiphase Mo-Mo3Si-Mo5SiB2(T2) alloys of various compositions and microstructures were investigated for oxidation resistance at 800 and 1300°C. The alloys varied in Si/B ratio from 1:1 to 1:2 and their microstructures were processed to have the Mo phase distributed as a continuous phase or as discrete particles. At 800°C, the alloys exhibited poor oxidation resistance regardless of Si/B ratio or their microstructures. Oxide scale consisted of MoO 3 and boron-containing glass. Alloys with lower Si/B ratio yielded silicate glass with lower viscosity that resulted in lower weight loss compared to the high Si/B ratio alloys. Intermediate layers of Mo and Mo-Si-O were observed adjacent to Mo5SiB2 and Mo3Si phases, respectively. At 1300°C, the multiphase alloys developed a protective glass scale with an intermediate layer of (Mo+glass) between the base alloy and outer glass scale. Boron-lean silicate glass was essential for the protection from further oxidation. For oxidation resistance at 1300°C, alloys require a high Si/B ratio. In terms of microstructures, the multiphase alloys consisting of small Mo particles uniformly dispersed in fine spacing of silicide phases provide better oxidation resistance than the alloys with continuous Mo dendrites. Glass preferentially formed at Mo3Si rather than at T2 phase. Vapor-solid diffusion experiments were carried out with single phase alloys containing either Mo3Si or T2 as the major phase, and the multiphase Mo-10Si-10B(at%) alloy. The alloys were exposed to vacuum to induce silicon loss resulting in the formation of a Mo layer. In addition, microprobe analysis was carried out for the determination of composition profiles across the (Mo+glass) layer and the external glass scale formed on the Mo-13.2Si-13.2B (at%) alloy oxidized at 1300°C. The microprobe data were analyzed for interdiffusion fluxes and interdiffusion coefficients with the aid of a computer program called "MultiDiFlux (c)". The effective interdiffusion

  9. XRD and XPS characterisation of transition metal silicide thin films

    Science.gov (United States)

    Tam, P. L.; Cao, Y.; Nyborg, L.

    2012-02-01

    Binary transition metal silicides based on the systems Ti-Si, Fe-Si, Ni-Si and Cr-Si were fabricated on Si wafers by means of ion-beam co-sputter deposition and subsequent annealing. The crystalline structures of the phases formed were identified from the characteristic patterns acquired by means of X-ray diffraction (XRD) measurements. The phase formation sequences were described by means of the Pretorius' effective heat of formation (EHF) model. For the Ti-Si, Fe-Si and Ni-Si systems, single phase thin films of TiSi2, β-FeSi2 and NiSi2 were generated as the model predicts, while a mixture of CrSi + CrSi2 phases was obtained for the Cr-Si system. The surface chemical condition of individual specimens was analysed by using X-ray photoelectron spectroscopy (XPS). The chemical shifts of transition metal 2p3/2 peaks from their metallic to silicide states were depicted by means of the Auger parameters and the Wagner plots. The positive chemical shift of 2.0 eV for Ni 2p3/2 peak of NiSi2 is mainly governed by the initial-state effects. For the other silicide specimens, the initial-state and final-state effects may oppose one another with similar impact. Consequently, smaller binding energy shifts of both negative and positive character are noted; a positive binding energy shift of 0.3 eV for the Fe 2p3/2 level was shown for β-FeSi2 and negative binding energy shifts of 0.1 and 0.3 eV were determined for CrSi + CrSi2 and TiSi2, respectively.

  10. Optical analysis of samarium doped sodium bismuth silicate glass.

    Science.gov (United States)

    Thomas, V; Sofin, R G S; Allen, M; Thomas, H; Biju, P R; Jose, G; Unnikrishnan, N V

    2017-01-15

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3+‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Samarium Monosulfide (SmS): Reviewing Properties and Applications.

    Science.gov (United States)

    Sousanis, Andreas; Smet, Philippe F; Poelman, Dirk

    2017-08-16

    In this review, we give an overview of the properties and applications of samarium monosulfide, SmS, which has gained considerable interest as a switchable material. It shows a pressure-induced phase transition from the semiconducting to the metallic state by polishing, and it switches back to the semiconducting state by heating. The material also shows a magnetic transition, from the paramagnetic state to an antiferromagnetically ordered state. The switching behavior between the semiconducting and metallic states could be exploited in several applications, such as high density optical storage and memory materials, thermovoltaic devices, infrared sensors and more. We discuss the electronic, optical and magnetic properties of SmS, its switching behavior, as well as the thin film deposition techniques which have been used, such as e-beam evaporation and sputtering. Moreover, applications and possible ideas for future work on this material are presented. Our scope is to present the properties of SmS, which were mainly measured in bulk crystals, while at the same time we describe the possible deposition methods that will push the study of SmS to nanoscale dimensions, opening an intriguing range of applications for low-dimensional, pressure-induced semiconductor-metal transition compounds.

  12. Growth and stability of dysprosium silicide nanostructures on Si(001)

    Science.gov (United States)

    Zeman, Matthew; Nemanich, Robert

    2007-03-01

    The growth and coarsening dynamics of epitaxial dysprosium silicide nanostructures on Si(001) are observed using tunable ultra-violet free electron laser excitation for photo-electron emission microscopy (PEEM). A dense array of compact silicide nanostructures is observed to coarsen during annealing at 950-1050C. Some of the nanostructures grow into large flat-topped rectangular islands at the expense of smaller islands which disappear via Ostwald ripening. The coarsening rate of the island distribution increases with increasing temperature, and the formation of a flat top on the growing islands is related to strain relaxation. Additionally, the shape and growth rates of the islands may be influenced by the island crystal structure and/or local island distributions. A subsequent deposition of dysprosium onto the surface results in the nucleation of new island and nanowire structures. Immediately after the deposition is terminated the nanowires begin to decay from the ends while the larger island structures grow. The decay of the wires can be attributed to Ostwald ripening and is explained in terms of the Gibbs-Thompson relation, where the high adatom concentration at the nanowire ends leads to the diffusion of adatoms away from the wires towards the larger surrounding structures. In situ movies will be presented which detail the growth and coarsening processes.

  13. Excitation induced spectroscopic study and quenching effect in cerium samarium codoped lithium aluminoborate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Parvinder; Kaur, Simranpreet [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, Gurinder Pal [Department of Physics, Khalsa College, Amritsar 143002 (India); Arora, Deepawali; Kumar, Sunil [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, D.P., E-mail: dpsinghdr@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2016-08-15

    Lithium aluminium borate host has been codoped with cerium and samarium to prepare glass by conventional melt quench technique. Their structural and spectroscopic investigation has been carried out using XRD, FTIR and density measurements. The UV‐Vis absorption spectra and fluorescence spectra (λ{sub exc}.=380 nm and 400 nm) have been studied for spectroscopic analysis. The amorphous nature of the prepared samples is shown by XRD. The density is increasing with addition of cerium at the expense of aluminium, keeping other components constant. FTIR study also shows the presence of compact and stable tetrahedral BO{sub 4} units thus supporting the density results. The UV‐ Vis absorption spectra show a shift of optical absorption edge towards longer wavelength along with an increase in intensity of peaks with rising samarium concentration. The fluorescence spectra show a blue shift and subsequent suppression of cerium peaks with addition of samarium.

  14. Influence of IR-laser irradiation on {alpha}-SiC-chromium silicides ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Vlasova, M. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Autonomous University of State of Morelos, Av. Universidad 1001-Col. Chamilpa, 62210 Cuernavaca, Morelos (Mexico)]. E-mail: kakazey@hotmail.com; Marquez Aguilar, P.A. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Autonomous University of State of Morelos, Av. Universidad 1001-Col. Chamilpa, 62210 Cuernavaca, Morelos (Mexico); Resendiz-Gonzalez, M.C. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Autonomous University of State of Morelos, Av. Universidad 1001-Col. Chamilpa, 62210 Cuernavaca, Morelos (Mexico); Kakazey, M. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Autonomous University of State of Morelos, Av. Universidad 1001-Col. Chamilpa, 62210 Cuernavaca, Morelos (Mexico); Bykov, A. [Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Str. Krzhizhanovskogo 3, Kiev 252680 (Ukraine); Gonzalez Morales, I. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Autonomous University of State of Morelos, Av. Universidad 1001-Col. Chamilpa, 62210 Cuernavaca, Morelos (Mexico)

    2005-09-15

    This project investigated the influence of IR-laser irradiation ({lambda} = 1064 nm, P = 240 mW) on composite ceramics SiC-chromium silicides (CrSi{sub 2}, CrSi, Cr{sub 5}Si{sub 3}) by methods of X-ray diffraction, electron microscopy, atomic force microscopy, and X-ray microanalysis. Samples were irradiated in air. It was established that a surface temperature of 1990 K was required to melt chromium silicides, evaporate silicon from SiC, oxidize chromium silicides, and enrich superficial layer by carbon and chromium oxide.

  15. Effect of samarium doping on the dielectric behavior of barium zircomium titanate ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Badapanda, T., E-mail: badapanda.tanmaya@gmail.com [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar, Odisha-752054 (India); Sarangi, S.; Behera, B. [School of Physics, Sambalpur University, Jyoti Vihar Sambalpur, Odisha-768019 (India); Anwar, S. [Colloids and Materials Chemistry, Institute of Minerals and Materials Technology, Bhubaneswar, Odisha-751013 (India); Sinha, T. P. [Department of Physics, Bose Institute, Kolkata-700009 (India)

    2014-04-24

    Samarium doped Barium Zirconium Titanate ceramic with general formula Ba{sub 1−x}Sm{sub 2x/3}Zr{sub 0.05}Ti{sub 0.95}O{sub 3} [x=0.0,0.01,0.02,0.03,0.04] has been prepared by high energy ball milling. The X-ray diffraction (XRD) patterns confirmed that these ceramics have a single phase with perovskite-type upto x≤0.03 and a small secondary phase exist at x=0.04. The temperature dependent dielectric study shows a ferroelectric phase transition and transition temperature decreases with an increase in the Samarium content.

  16. Lithium Bromide/Water as Additives in Dearomatizing Samarium-Ketyl (Hetero)Arene Cyclizations.

    Science.gov (United States)

    Rao, Chintada Nageswara; Bentz, Christoph; Reissig, Hans-Ulrich

    2015-11-02

    New conditions for dearomatizing samarium-ketyl (hetero)arene cyclizations are reported. In many examples of these samarium diiodide-mediated reactions, lithium bromide and water can be used as additives instead of the carcinogenic and mutagenic hexamethylphosphoramide (HMPA). The best results were obtained for the cyclizations of N-acylated indole derivatives delivering the expected indolines in good yields and excellent diastereoselectivities. A new type of cyclization delivering indolyl-substituted allene derivatives is also described. The scope and limitations of the lithium bromide/water system are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Comparison of nickel silicide and aluminium ohmic contact metallizations for low-temperature quantum transport measurements

    Directory of Open Access Journals (Sweden)

    Polley Craig

    2011-01-01

    Full Text Available Abstract We examine nickel silicide as a viable ohmic contact metallization for low-temperature, low-magnetic-field transport measurements of atomic-scale devices in silicon. In particular, we compare a nickel silicide metallization with aluminium, a common ohmic contact for silicon devices. Nickel silicide can be formed at the low temperatures (<400°C required for maintaining atomic precision placement in donor-based devices, and it avoids the complications found with aluminium contacts which become superconducting at cryogenic measurement temperatures. Importantly, we show that the use of nickel silicide as an ohmic contact at low temperatures does not affect the thermal equilibration of carriers nor contribute to hysteresis in a magnetic field.

  18. NMOS contact resistance reduction with selenium implant into NiPt silicide

    Science.gov (United States)

    Rao, K. V.; Khaja, F. A.; Ni, C. N.; Muthukrishnan, S.; Darlark, A.; Lei, J.; Peidous, I.; Brand, A.; Henry, T.; Variam, N.; Erokhin, Y.

    2012-11-01

    A 25% reduction in NMOS contact resistance (Rc) was achieved by Selenium implantation into NiPt silicide film in VIISta Trident high-current single-wafer implanter. The Trident implanter is designed for shallow high-dose implants with high beam currents to maintain high throughput (for low CoO), with improved micro-uniformity and no energy contamination. The integration of Se implant was realized using a test chip dedicated to investigating silicide/junction related electrical properties and testable after silicidation. The silicide module processes were optimized, including the pre-clean (prior to RF PVD NiPt dep) and pre- and post-implant anneals. A 270°C soak anneal was used for RTP1, whereas a msec laser anneal was employed for RTP2 with sufficient process window (800-850°C), while maintaining excellent junction characteristics without Rs degradation.

  19. Silicon to Nickel Silicide Longitudinal Nanowire Heterostructures: Synthesis, Electrical Characterization and Novel Devices

    OpenAIRE

    Weber, Walter Michael

    2009-01-01

    The scope of this thesis is the synthesis and electrical characterization of Si to Ni silicide nanowire heterostructures with the focus on investigating their electronic transport properties and conceiving a novel type of transistor. Intrinsic Si nanowires (SiNW) were grown employing the vapor-liquid-solid mechanism. A central part of this thesis is the development of the longitudinal intrusion of Ni silicide into the SiNWs resulting in interfaces with a sharpness of at most a couple of n...

  20. Status of the atomized uranium silicide fuel development at KAERI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.K.; Kim, K.H.; Park, H.D.; Kuk, I.H. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-08-01

    While developing KMRR fuel fabrication technology an atomizing technique has been applied in order to eliminate the difficulties relating to the tough property of U{sub 3}Si and to take advantage of the rapid solidification effect of atomization. The comparison between the conventionally comminuted powder dispersion fuel and the atomized powder dispersion fuel has been made. As the result, the processes, uranium silicide powdering and heat treatment for U{sub 3}Si transformation, become simplified. The workability, the thermal conductivity and the thermal compatibility of fuel meat have been investigated and found to be improved due to the spherical shape of atomized powder. In this presentation the overall developments of atomized U{sub 3}Si dispersion fuel and the planned activities for applying the atomizing technique to the real fuel fabrication are described.

  1. Development of molecular dynamics potential for uranium silicide fuels

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jianguo; Zhang, Yongfeng; Hales, Jason D.

    2016-09-01

    Use of uranium–silicide (U-Si) in place of uranium dioxide (UO2) is one of the promising concepts being proposed to increase the accident tolerance of nuclear fuels. This is due to a higher thermal conductivity than UO2 that results in lower centerline temperatures. U-Si also has a higher fissile density, which may enable some new cladding concepts that would otherwise require increased enrichment limits to compensate for their neutronic penalty. However, many critical material properties for U-Si have not been determined experimentally. For example, silicide compounds (U3Si2 and U3Si) are known to become amorphous under irradiation. There was clear independent experimental evidence to support a crystalline to amorphous transformation in those compounds. However, it is still not well understood how the amorphous transformation will affect on fuel behavior. It is anticipated that modeling and simulation may deliver guidance on the importance of various properties and help prioritize experimental work. In order to develop knowledge-based models for use at the engineering scale with a minimum of empirical parameters and increase the predictive capabilities of the developed model, inputs from atomistic simulations are essential. First-principles based density functional theory (DFT) calculations will provide the most reliable information. However, it is probably not possible to obtain kinetic information such as amorphization under irradiation directly from DFT simulations due to size and time limitations. Thus, a more feasible way may be to employ molecular dynamics (MD) simulation. Unfortunately, so far no MD potential is available for U-Si to discover the underlying mechanisms. Here, we will present our recent progress in developing a U-Si potential from ab initio data. This work is supported by the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program funded by the U.S. Department of Energy, Office of Nuclear Energy.

  2. One-step synthesis of samarium-doped ceria and its CO catalysis

    Indian Academy of Sciences (India)

    The samarium-doped ceria (SDC) nanospheres were prepared by the one-step hydrothermal method and characterized by transmission electron microscope, scanning electron microscope, powder X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive spectrometer and Raman spectra. According to the ...

  3. A spectroscopic comparison of samarium-doped LiYF4 and KY3F10

    NARCIS (Netherlands)

    Wells, J. P. R.; Sugiyama, A.; Han, T. P. J.; Gallagher, H. G.

    2000-01-01

    Laser selective excitation and fluorescence has been performed on LiYF4 and KY3F10 doped with samarium ions. In LiYF4, a single, tetragonal symmetry center associated with isovalent substitution of Sm3+ with lattice yttrium ions is present. By contrast, three Sm2+ centres and a single, tetragonal

  4. Technology CAD of silicided Schottky barrier MOSFET for elevated source-drain engineering

    Energy Technology Data Exchange (ETDEWEB)

    Saha, A.R. [Department of Electronics and ECE, IIT, Kharagpur 721302 (India)]. E-mail: ars.iitkgp@gmail.com; Chattopadhyay, S. [Department of Electronics and ECE, IIT, Kharagpur 721302 (India); School of Electrical, Electronics and Computer Engineering, University of Newcastle, Newcastle upon Tyne (United Kingdom); Bose, C. [Department of Electronics and Telecommunication Engineering, Jadavpur University, Calcutta 700032 (India); Maiti, C.K. [Department of Electronics and ECE, IIT, Kharagpur 721302 (India)

    2005-12-05

    Technology CAD has been used to study the performance of a silicided Schottky barrier (SB) MOSFET with gate, source and drain contacts realized with nickel-silicide. Elevated source-drain structures have been used towards the S/D engineering of CMOS devices. A full process-to-device simulation has been employed to predict the performance of sub-micron SB n-MOSFETs for the first time. A model for the diffusion and alloy growth kinetics has been incorporated in SILVACO-ATLAS and ATHENA to explore the processing and design parameter space for the Ni-silicided MOSFETs. The temperature and concentration dependent diffusion model for NiSi have been developed and necessary material parameters for nickel-silicide and epitaxial-Si have been incorporated through the C-interpreter function. Two-dimensional (2D) process-to-device simulations have also been used to study the dc and ac (RF) performance of silicided Schottky barrier (SB) n-MOSFETs. The extracted sheet resistivity, as a function of annealing temperature of the silicided S/D contacts, is found to be lower than the conventional contacts currently in use. It is also shown that the Technology CAD has the full capability to predict the possible dc and ac performance enhancement of a MOSFET with elevated S/D structures. While the simulated dc performance shows a clear enhancement, the RF analyses show no performance degradation in the cut-off frequency/propagation delay and also improve the ac performance due to the incorporation of silicide contacts in the S/D region.

  5. The Use of a Flexible Calix[4]arene Template to Stabilize a Cyclooctatetraindiyl Samarium-Potassium Complex

    Directory of Open Access Journals (Sweden)

    Geoffroy Guillemot

    2013-01-01

    Full Text Available A sandwich compound of cyclooctatetraendiyl (COT2− samarium-potassium was synthesized and analyzed using a flexible calix[4]arene dianion. This compound, [p-tBu-calix[4]-(OMe2(O2]arenediyl-samarium-(η8-cyclooctatetraendiyl-potassium (tetrahydrofurane3, is constructed as a linear sequence L-Sm--K-, where L, , and are specific ligands with L = O,O-dimethyl-calix[4]arene2−, = cyclo-octatetraendiyl, and = tetrahydrofurane templates.

  6. Epitaxial insertion of gold silicide nanodisks during the growth of silicon nanowires.

    Science.gov (United States)

    Um, Han-Don; Jee, Sang-Won; Park, Kwang-Tae; Jung, Jin-Young; Guo, Zhongyi; Lee, Jung-Ho

    2011-07-01

    Nanodisk-shaped, single-crystal gold silicide heterojunctions were inserted into silicon nanowires during vapor-liquid-solid growth using Au as a catalyst within a specific range of chlorine-to-hydrogen atomic ratio. The mechanism of nanodisk formation has been investigated by changing the source gas ratio of SiCl4 to H2. We report that an over-supply of silicon into the Au-Si liquid alloy leads to highly supersaturated solution and enhances the precipitation of Au in the silicon nanowires due to the formation of unstable phases within the liquid alloy. It is shown that the gold precipitates embedded in the silicon nanowires consisted of a metastable gold silicide. Interestingly, faceting of gold silicide was observed at the Au/Si interfaces, and silicon nanowires were epitaxially grown on the top of the nanodisk by vapor-liquid-solid growth. High resolution transmission electron microscopy confirmed that gold silicide nanodisks are epitaxially connected to the silicon nanowires in the direction of growth direction. These gold silicide nanodisks would be useful as nanosized electrical junctions for future applications in nanowire interconnections.

  7. Effect of silicide/silicon hetero-junction structure on thermal conductivity and Seebeck coefficient.

    Science.gov (United States)

    Choi, Wonchul; Park, Young-Sam; Hyun, Younghoon; Zyung, Taehyoung; Kim, Jaehyeon; Kim, Soojung; Jeon, Hyojin; Shin, Mincheol; Jang, Moongyu

    2013-12-01

    We fabricated a thermoelectric device with a silicide/silicon laminated hetero-structure by using RF sputtering and rapid thermal annealing. The device was observed to have Ohmic characteristics by I-V measurement. The temperature differences and Seebeck coefficients of the proposed silicide/silicon laminated and bulk structure were measured. The laminated thermoelectric device shows suppression of heat flow from the hot to cold side. This is supported by the theory that the atomic mass difference between silicide and silicon creates a scattering center for phonons. The major impact of our work is that phonon transmission is suppressed at the interface between silicide and silicon without degrading electrical conductivity. The estimated thermal conductivity of the 3-layer laminated device is 126.2 +/- 3.7 W/m. K. Thus, by using the 3-layer laminated structure, thermal conductivity is reduced by around 16% compared to bulk silicon. However, the Seebeck coefficient of the thermoelectric device is degraded compared to that of bulk silicon. It is understood that electrical conductivity is improved by using silicide as a scattering center.

  8. Simulated Fission Gas Behavior in Silicide Fuel at LWR Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinbin [Argonne National Lab. (ANL), Argonne, IL (United States); Mo, Kun [Argonne National Lab. (ANL), Argonne, IL (United States); Yacout, Abdellatif [Argonne National Lab. (ANL), Argonne, IL (United States); Harp, Jason [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-15

    As a promising candidate for the accident tolerant fuel (ATF) used in light water reactors (LWRs), the fuel performance of uranium silicide (U3Si2) at LWR conditions needs to be well-understood. However, existing experimental post-irradiation examination (PIE) data are limited to the research reactor conditions, which involve lower fuel temperature compared to LWR conditions. This lack of appropriate experimental data significantly affects the development of fuel performance codes that can precisely predict the microstructure evolution and property degradation at LWR conditions, and therefore evaluate the qualification of U3Si2 as an AFT for LWRs. Considering the high cost, long timescale, and restrictive access of the in-pile irradiation experiments, this study aims to utilize ion irradiation to simulate the inpile behavior of the U3Si2 fuel. Both in situ TEM ion irradiation and ex situ high-energy ATLAS ion irradiation experiments were employed to simulate different types of microstructure modifications in U3Si2. Multiple PIE techniques were used or will be used to quantitatively analyze the microstructure evolution induced by ion irradiation so as to provide valuable reference for the development of fuel performance code prior to the availability of the in-pile irradiation data.

  9. Solar nebula heterogeneity in p-process samarium and neodymium isotopes.

    Science.gov (United States)

    Andreasen, Rasmus; Sharma, Mukul

    2006-11-03

    Bulk carbonaceous chondrites display a deficit of approximately 100 parts per million (ppm) in 144Sm with respect to other meteorites and terrestrial standards, leading to a decrease in their 142Nd/144Nd ratios by approximately 11 ppm. The data require that samarium and neodymium isotopes produced by the p process associated with photodisintegration reactions in supernovae were heterogeneously distributed in the solar nebula. Other samarium and neodymium isotopes produced by rapid neutron capture (r process) in supernovae and by slow neutron capture (s process) in red giants were homogeneously distributed. The supernovae sources supplying the p- and r-process nuclides to the solar nebula were thus disconnected or only weakly connected.

  10. Anisotropic thermal expansion of Ni, Pd and Pt germanides and silicides

    Science.gov (United States)

    Geenen, F. A.; Knaepen, W.; Moens, F.; Brondeel, L.; Leenaers, A.; Van den Berghe, S.; Detavernier, C.

    2016-07-01

    Silicon or germanium-based transistors are nowadays used in direct contact with silicide or germanide crystalline alloys for semiconductor device applications. Since these compounds are formed at elevated temperatures, accurate knowledge of the thermal expansion of both substrate and the contact is important to address temperature depending effects such as thermal stress. Here we report the linear coefficients of thermal expansion of Ni-, Pd- and Pt-based mono-germanides, mono-silicides and di-metal-silicides as determined by powder-based x-ray diffraction between 300 and 1225 K. The investigated mono-metallic compounds, all sharing the MnP crystal structure, as well as Pd2Si and Pt2Si exhibit anisotropic expansion. By consequence, this anisotropic behaviour should be taken into account for evaluating the crystal unit’s cell at elevated temperatures.

  11. Tuning magnetic response of epitaxial iron-silicide nanoislands by controlled self-assembled growth

    Science.gov (United States)

    Goldfarb, I.; Camus, Y.; Dascalu, M.; Cesura, F.; Chalasani, R.; Kohn, A.

    2017-07-01

    We investigated the dependence of the magnetic response from epitaxial Si-rich iron-silicide nanostructures on their geometry. By varying substrate orientation and deposition parameters, we altered the growth kinetics and the lattice matching conditions at the silicide/silicon interface. These affected the silicide nanoisland crystal structure, size, shape, and proximity due to spatial ordering and, consequently, their magnetic response in terms of shape and opening of the respective hysteresis loops. In particular, we demonstrated correlation between magnetic anisotropy, expressed as the hysteresis coercive field, and the nanoisland spatial length-to-width aspect ratio. This correlation is explained by the contribution of undercoordinated island edge atoms to the overall measured magnetic behavior of the nanoisland arrays. Further, the island self-ordering along periodic surface steps adds dipolar interactions between the otherwise superparamagnetic nanoislands, consequently resulting in a magnetic response resembling that of a superspin glass.

  12. Samarium(II) iodide-mediated reductive annulations of ketones bearing a distal vinyl epoxide moiety

    Energy Technology Data Exchange (ETDEWEB)

    Molander, G.A.; Shakya, S.R. [Univ. of Colorado, Boulder, CO (United States)

    1996-08-23

    It was found that samarium (II) iodide promotes the intramolecular coupling of ketones with distal epoxy olefins while in the presence of hexamethylphosphoramide (HPMA). A number of epoxide compounds (1 a-k) fragment to form carbocycles with allylic alcohol side chains with high diastereoselectivity (2 a-k). Substituting tetramethylguanidine for HPMA reduces the diastereoselectivity. Adding Pd(0) as a catalyst reverses the diastereoselective sense. 40 refs., 1 tab.

  13. A temporal three-dimensional simulation of samarium release in the ionosphere

    Science.gov (United States)

    Zhao, Hai-Sheng; Feng, Jie; Xu, Zheng-Wen; Wu, Jian; Wu, Zhen-Sen; Xu, Bin; Xue, Kun; Xu, Tong; Hu, Yan-Li

    2016-10-01

    For understanding plasma processes of the ionosphere and magnetosphere, the alkali and alkaline-earth metals are usually released in space for artificially increasing the electron density. However, it is a limitation that these releases must be in sunlight where the photoionization can take place. In recent years, the lanthanide metals, such as samarium, have been released to produce electrons in reaction with atomic oxygen in the upper space. The reaction could proceed without sunlight so that the restriction on experimental periods is broken. Unfortunately, any sophisticated models even preliminary ones are unavailable yet in the literature. A temporal three-dimensional model is presented for the samarium release in detail with respect to various altitudes and mass. Especially, the plasma diffusion equation is remarkably extended from 2-D to 3-D by importing the influence of geomagnetic declination, which could be also useful for other chemical releases. The field-aligned terms are brought so as to the presented model can describe the diffusion along the geomagnetic field subtly. On the basis of the presented model, behaviors of radio waves propagating through the release area are simulated by using ray tracing. This model could be as the theoretical support for samarium releases, and it also helpful for the research on the generation and evolution of the ionosphere irregularities.

  14. Crystal Structure of Silicides in a Ti - 0.7 WT.% Si Nanostructured Alloy

    Science.gov (United States)

    Ivanov, M. B.; Manokhin, S. S.; Kolobova, A. Yu.

    2017-09-01

    Using warm, lengthwise grooved-roll processing of the Ti - 0.7 wt.% Si alloy, a nanostructured state is formed in it at 873 K with the grain-subgrain elements measuring about 280 nm. The titanium silicides precipitating during the dynamic strain-induced aging of the alloy are investigated by the methods of high-resolution scanning electron microscopy. It is found that the shape of the silicides is close to spherical, they have an FCClattice and an incoherent interface with the matrix.

  15. Optical anisotropy of quasi-1D rare-earth silicide nanostructures on Si(001)

    Science.gov (United States)

    Chandola, S.; Speiser, E.; Esser, N.; Appelfeller, S.; Franz, M.; Dähne, M.

    2017-03-01

    Rare earth metals are known to interact strongly with Si(001) surfaces to form different types of silicide nanostructures. Using STM to structurally characterize Dy and Tb silicide nanostructures on vicinal Si(001), it will be shown that reflectance anisotropy spectroscopy (RAS) can be used as an optical fingerprint technique to clearly distinguish between the formation of a semiconducting two-dimensional wetting layer and the metallic one-dimensional nanowires. Moreover, the distinctive spectral features can be related to structural units of the nanostructures. RAS spectra of Tb and Dy nanostructures are found to show similar features.

  16. Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

    CERN Document Server

    Caloz, Misael; Timoney, Nuala; Weiss, Markus; Gariglio, Stefano; Warburton, Richard J; Schönenberger, Christian; Renema, Jelmer; Zbinden, Hugo; Bussieres, Felix

    2016-01-01

    We experimentally investigate the detection mechanism in a meandered molybdenum silicide (MoSi) superconducting nanowire single-photon detector by characterising the detection probability as a function of bias current in the wavelength range of 750 to 2050 nm. Contrary to some previous observations on niobium nitride (NbN) or tungsten silicide (WSi) detectors, we find that the energy-current relation is nonlinear in this range. Furthermore, thanks to the presence of a saturated detection efficiency over the whole range of wavelengths, we precisely quantify the shape of the curves. This allows a detailed study of their features, which are indicative of both Fano fluctuations and position-dependent effects.

  17. Carbon mediated reduction of silicon dioxide and growth of copper silicide particles in uniform width channels

    DEFF Research Database (Denmark)

    Pizzocchero, Filippo; Bøggild, Peter; Booth, Tim

    2013-01-01

    We show that surface arc-discharge deposited carbon plays a critical intermediary role in the breakdown of thermally grown oxide diffusion barriers of 90 nm on a silicon wafer at 1035°C in an Ar/H2 atmosphere, resulting in the formation of epitaxial copper silicide particles in ≈ 10 μm wide...... channels, which are aligned with the intersections of the (100) surface of the wafer and the {110} planes on an oxidized silicon wafer, as well as endotaxial copper silicide nanoparticles within the wafer bulk. We apply energy dispersive x-ray spectroscopy, in combination with scanning and transmission...

  18. Growth, structure and lattice dynamics of rare earth silicide nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Anja

    2015-07-13

    In the present thesis the epitaxial growth, crystal structure, stoichiometry, thermal stability and lattice dynamics of self-organized EuSi{sub 2} and DySi{sub 2} films, nanoislands and nanowires are investigated. The rare earth silicide (RESi) nanostructures have attracted considerable interest due to their high conductivity, very low Schottky barrier heights, remarkable chemical stability, self-organization in high area density and defects-free nano-objects with tunable size and shape, and the direct integration into the Si technology. The extensive research is driven by the continuous downscaling of the CMOS electronics that require new approaches in the devices architecture and circuits interconnects. Although RESi nanostructures attracted a lot of interest already several years ago and a lot of research has been done in this field, the lattice dynamics of these materials are still unknown. Recent developments at third generation synchrotron radiation sources have brought their performance to a stage where phonon spectroscopy of nanostructures and thin layers became feasible using nuclear inelastic X-ray scattering. This novel experimental technique is based on the process of phonon-assisted nuclear resonant absorption/emission of X-rays from the nuclei of Moessbauer-active isotopes. The method provides direct access to the phonon density of states (DOS) of the investigated element. Together with the ab initio calculations it was possible to get a comprehensive understanding of the lattice dynamics. EuSi{sub 2} films and nanoislands and DySi{sub 2} films, nanoislands and nanowires have been grown on the vicinal Si(001) surface by molecular beam epitaxy. While DySi{sub 2} was grown following known growth procedures, the growth conditions for EuSi{sub 2} had to be established first. EuSi{sub 2} was grown at two different growth conditions to study the influence of crystal structure and morphology upon different growth temperatures. The structure has been

  19. Water splitting and electricity with semiconducting silicides in sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Demuth, Martin [Max-Planck-Institut fuer Bioanorganische Chemie, Muelheim an der Ruhr (Germany); H2 Solar GmbH, Loerrach (Germany); Kerpen, Klaus; Kuklya, Andriy; Wuestkamp, Marc-Andre [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    2010-07-01

    Generation of hydrogen and oxygen from water is described using mainly the semiconductor titanium disilicide as catalyst and halogen light which closely mimics solar radiation. The reactions are carried out under non-aerobic conditions, i.e., under nitrogen. High efficiencies are reached at 1.1-1.2 bar pressure. In the first phase of these reactions the catalytically active centers are built up. During this phase of reaction the kinetics of the water splitting process is growing in and leads to a linear dependence in the further course of the reactions which consists of >96% water splitting to yield hydrogen and oxygen in a 2:1 ratio. Hydrogen is partially and reversibly stored physically, depending on temperature. Oxygen behaves differently since it is stored entirely under the applied reaction conditions (50-80 C and light) and can be liberated from storage upon heating the slurries in the dark. This allows convenient separation of hydrogen and oxygen. The stability of titanium disilicide has been positively tested over several months. This material is abundant and inexpensive besides that it absorbs most of the solar radiation. Further, XRD and XPS studies show that titanium disilicide is 80% crystalline and the oxide formation is limited to a few molecular layers in depth. By using labeled water it was shown that labeled dioxygen appears in the gas phase of such reactions, this showing definitively that hydrogen evolution occuring here stems from photochemical splitting of water. Further, water splitting is part of a project which involves photoelectrochemistry and in which the silicides are used as light-receiving electrode and transition metal-coated anodes serve to split water. (orig.)

  20. Radiation Re-solution Calculation in Uranium-Silicide Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andersson, Anders David Ragnar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Unal, Cetin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-27

    The release of fission gas from nuclear fuels is of primary concern for safe operation of nuclear power plants. Although the production of fission gas atoms can be easily calculated from the fission rate in the fuel and the average yield of fission gas, the actual diffusion, behavior, and ultimate escape of fission gas from nuclear fuel depends on many other variables. As fission gas diffuses through the fuel grain, it tends to collect into intra-granular bubbles, as portrayed in Figure 1.1. These bubbles continue to grow due to absorption of single gas atoms. Simultaneously, passing fission fragments can cause collisions in the bubble that result in gas atoms being knocked back into the grain. This so called “re-solution” event results in a transient equilibrium of single gas atoms within the grain. As single gas atoms progress through the grain, they will eventually collect along grain boundaries, creating inter-granular bubbles. As the inter-granular bubbles grow over time, they will interconnect with other grain-face bubbles until a pathway is created to the outside of the fuel surface, at which point the highly pressurized inter-granular bubbles will expel their contents into the fuel plenum. This last process is the primary cause of fission gas release. From the simple description above, it is clear there are several parameters that ultimately affect fission gas release, including the diffusivity of single gas atoms, the absorption and knockout rate of single gas atoms in intra-granular bubbles, and the growth and interlinkage of intergranular bubbles. Of these, the knockout, or re-solution rate has an particularly important role in determining the transient concentration of single gas atoms in the grain. The re-solution rate will be explored in the following sections with regards to uranium-silicide fuels in order to support future models of fission gas bubble behavior.

  1. Liquid–liquid anion exchange extraction studies of samarium(III from salicylate media using high molecular weight amine

    Directory of Open Access Journals (Sweden)

    Aniruddha M. Mandhare

    2015-07-01

    Full Text Available Liquid–liquid extraction and separation of samarium(III were carried out by using 0.025 mol dm−3 2-octylaminopyridine(2-OAP in xylene at 298 K. The extraction behavior of samarium was studied as a function of pH, weak acid concentration, extractant concentration, diluent, and equilibration time. Samarium was quantitatively extracted at pH 7.5 to 10.0 from 0.01 mol dm−3 sodium salicylate solution with 0.025 mol dm−3 2-OAP. The possible composition of the extracted species in organic phase has been determined by using model of slope analysis method and extraction mechanism was found to proceed via an anion exchange mechanism. The stripping efficiency was found to be quantitative in HNO3, HCl and CH3COOH. The robustness of the procedure was demonstrated by the average recoveries obtained (>99.6% for samarium(III extraction in the presence of several cations and anions which are commonly associated with it. The proposed method facilitates the separation and determination of samarium(III from binary and synthetic mixtures. The various thermodynamic functions like free energy (ΔG, enthalpy (ΔH and entropy (ΔS of extraction mechanism were discussed.

  2. Impact of laser anneal on NiPt silicide texture and chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Feautrier, C.; Ozcan, A. S.; Lavoie, C.; Valery, A.; Beneyton, R.; Borowiak, C.; Clément, L.; Pofelski, A.; Salem, B.

    2017-06-14

    We have combined synchrotron X-ray pole figure measurements and transmission electron microscopy (TEM) nano-beam diffraction to study the impact of millisecond laser anneal on the texture and microstructure of NiPt silicide thin films. The powerful use of nano-beam diffraction in plan-view geometry allows here for both a mapping of grain orientation and intra-grain measurements even if these crystalline grains become very small. With this unique combination of local and large-scale probes, we find that silicide formation on n and p doped substrates using laser annealing results in smaller grains compared with the films processed using standard rapid thermal annealing. The laser annealed samples also result in grains that are more epitaxially oriented with respect to the Si substrate. For n-type substrate, the film is dominated by (020) and (013) oriented fibers with significant levels of intra-grain bending (transrotation) observed in both types of grains. For p-type substrates, mostly epitaxially aligned grains are detected. TEM coupled with energy-dispersive X-ray analysis was also used to study the elemental distribution in the silicide samples. Here, we confirm that laser anneal leads to a larger accumulation of platinum at the silicide-substrate interface and modifies the distribution of dopants throughout the film.

  3. Role of Ti3Al/silicides on tensile properties of Timetal 834 at various ...

    Indian Academy of Sciences (India)

    Extremely fine coherent precipitates of ordered Ti3Al and relatively coarse incoherent precipitates of 2 silicide exist together in the near -titanium alloy, Timetal 834, in the dual phase matrix of primary and transformed . In order to assess the role of these precipitates, three heat treatments viz. WQ, WQ–A and WQ–OA, ...

  4. Effect of pre-treatment and nickel layer thickness on nickel silicide/silicon carbide contact

    Science.gov (United States)

    Cao, Yu; Nyborg, Lars; Jelvestam, Urban; Yi, Danqing

    2005-03-01

    This investigation deals with the impact of pre-treatment and Ni thickness on the reactions of Ni-silicide/SiC contact fabrication. The specimens have been prepared by sputter depositing 3-100 nm Ni layer on 4H-SiC wafer followed by annealing at 800 °C in vacuum for 20 min. The results by means of XPS show as follows: among the chemical cleaning procedures which have been tested, the recipe NH4OH:H2O2:H2O = 1:1:5, 85 °C, 5 min; HF 10%, 80 °C, 2 min; boiling water 10 min is the most effective for SiC substrates. However, due to short time exposure in the air before experiment, certain contamination re-occurs. After annealing, the dominant silicide formed is Ni2Si, whereas C on the surface is graphite. Argon ion etching before the Ni deposition helps the formation of multi-layer structure. For the samples without pre-treatment or with chemical cleaning procedure, there is more C agglomerated at the surface and no multi-layer structure formed. Under the action of Ar ion etching, SiC decomposes more quickly and Ni diffuses faster. This effect together with limited C diffusivity in the formed silicide is a probable reason for the formation of the multi-layer structure. The silicides formed at the interface are dependent on the Ni layer thickness and substrate surface condition.

  5. Waste Photovoltaic Panels for Ultrapure Silicon and Hydrogen through the Low-Temperature Magnesium Silicide.

    Czech Academy of Sciences Publication Activity Database

    Dytrych, Pavel; Bumba, Jakub; Kaštánek, František; Fajgar, Radek; Koštejn, Martin; Šolcová, Olga

    2017-01-01

    Roč. 56, č. 45 (2017), s. 12863-12869 ISSN 0888-5885 R&D Projects: GA ČR GA15-14228S Institutional support: RVO:67985858 Keywords : magnesium silicide * waste photovoltaic panels * ultrapure silicon Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.843, year: 2016

  6. High pressure studies on uranium and thorium silicide compounds: Experiment and theory

    DEFF Research Database (Denmark)

    Yagoubi, S.; Heathman, S.; Svane, A.

    2013-01-01

    The actinide silicides ThSi, USi and USi2 have been studied under high pressure using both theory and experiment. High pressure synchrotron X-ray diffraction experiments were performed on polycrystalline samples in diamond anvil cells at room temperature and for pressures up to 54, 52 and 26 GPa,...

  7. The development of titanium silicide - boron doped polysilicon resistive temperature sensors

    NARCIS (Netherlands)

    Vereshchagina, E.; Vereshchagina, E.; Wolters, Robertus A.M.; Gardeniers, Johannes G.E.

    2011-01-01

    Thin films of titanium silicide (TiSi2) formed on heavily boron-doped polycrystalline silicon (poly-Si/B+) were applied for the first time for resistive temperature sensing. The temperature sensors exhibited a high-temperature coefficient of resistance of 3.8 × 10−3 ◦C−1, a linear dependence of

  8. Cross-Bridge Kelvin Resistor (CBKR) structures for silicide-semiconductor junctions characterization

    NARCIS (Netherlands)

    Stavitski, N.; van Dal, M.J.H.; Klootwijk, J.H.; Wolters, Robertus A.M.; Kovalgin, Alexeij Y.; Schmitz, Jurriaan

    2006-01-01

    Analyzing the contact geometry factors for the conventional CBKR structures, it appeared that the contact geometries conventionally used for the metal-to-silicide contact resistance measurements were not always satisfactory to reveal the specific contact resistance values. To investigate these

  9. Role of Ti3Al/silicides on tensile properties of Timetal 834 at various ...

    Indian Academy of Sciences (India)

    WINTEC

    conditions. Tensile properties in the above three heat treated conditions were determined at room tempera- ture, 673 K and 873 K. It was observed that largely Ti3Al precipitates were responsible for increase in the yield strength and decrease in ductility in this alloy. Keywords. Near α-titanium alloy; Timetal 834; Ti3Al/silicide ...

  10. Shape modification of Si nanowires by using faceted silicide catalysts nucleated in Au-Si catalyst solution during the growth

    Directory of Open Access Journals (Sweden)

    Erchao Meng

    2013-09-01

    Full Text Available The shape modification of Si nanowires is demonstrated using faceted solid silicide catalysts. The Si nanowires were grown on Si(111 substrates covered with Au as a catalyst using MnCl2 and Si powders as source materials. The solid silicide catalysts were nucleated and formed in the Au-Si catalyst solution at the top of the nanowires during the growth. The faceted solid silicides grew larger with increased growth time and played a role as a solid catalyst. The faceted shape of the catalyst defines the shape of the faceted Si nanowire. The squared Si nanowires were grown with the growth direction of Si[111] and the sidewalls of {110} and {211} planes. The growth evolution of the faceted Si nanowires occurs by a vapor-liquid-solid mechanism followed by the silicide vapor-solid-solid mechanism.

  11. Samarium(II) iodide-mediated intramolecular conjugate additions of alpha,beta-unsaturated lactones.

    Science.gov (United States)

    Molander, Gary A; St Jean, David J

    2002-05-31

    Samarium(II) iodide, in the presence of catalytic amounts of nickel(II) iodide, has been used to promote intramolecular conjugate additions of alkyl halides onto alpha,beta-unsaturated lactones. This process has been shown to be applicable to a number of alpha,beta-unsaturated lactones, including tetrasubstituted olefins, and has been demonstrated to be quite general for the formation of saturated bicyclic and tricyclic lactones. The method presented herein provides a mild, efficient process to form structurally complex lactones from simple precursors.

  12. Ekstraksi Pemisahan Neodimium dari Samarium, Itrium dan Praseodimium Memakai Tri Butil Fosfat

    Directory of Open Access Journals (Sweden)

    Maria Veronica Purwani

    2017-05-01

    Full Text Available The extraction of Nd(OH3 (neodymium hydroxide concentrate containing Y (yttrium, Sm (samarium and Pr (praseodymium as product of monazite processed has been done. The purpose of this study is to determine the separation of Nd from Y, Pr and Nd Sm in Nd concentrate. The aqueous phase was concentrated Nd (OH3 in HNO3 and extractant while organic phase was Tri Butyl Phosphate (TBP in kerosene. Parameters studied were pH and concentration feed, concentration of TBP in kerosene, extraction time and stirring speed. The result showed that the optimization of separation extraction neodymium from samarium, yttrium and praseodymium in Nd(OH3 concentrated with TBP, obtained the optimum condition of pH = 0.2, concentration of feed 100 g /L, concentration of TBP in kerosene 5%, extraction time 15 minutes and stirring speed 150 rpm. With the conditions, Separation Factor (SF obtained for Nd-Y, Nd-Pr, Nd-Sm are 2.242, 4.811, 4.002 respectively, while D and extraction efficiency of Nd are 0.236 and 19.07%.

  13. X-Band Microwave Reflection Properties of Samarium/Bismuth-Substituted Barium Lanthanum Titanate Ceramics

    Science.gov (United States)

    Bahel, Shalini; Pubby, Kunal; Narang, Sukhleen Bindra

    2017-03-01

    Samarium/bismuth-substituted barium lanthanum titanate ceramics with chemical composition Ba4 (La_{1 - y - z} Smy Biz )_{9.33} Ti_{18} O_{54} ( y = 0.5, 0.7; z = 0.05, 0.10, 0.15), intended as microwave reflecting materials, have been investigated in microwave X-band (8.2 GHz to 12.4 GHz) and the effect of substitution on their dielectric properties, i.e., dielectric constant and dielectric loss tangent, has been studied by vector network analyzer. Dielectric analysis showed that the dielectric constant increased with increasing samarium as well as bismuth content. Dielectric relaxation was observed for all samples in the scanned frequency range. Microwave reflection and transmission analysis of ceramic pellets of thickness 4 mm was carried out using two methods, i.e., open- and short-circuit approach, both indicating very high values of reflected power and very low values of transmitted power for all the doped materials in comparison with the base composition. The doped compositions are therefore potential microwave shielding materials for use in anechoic chambers, microwave laboratories, and radar equipment. Double-layer reflectors are also proposed, having better reflection properties (˜99% reflection) compared with single-layer reflectors.

  14. Microstructure and hysteresis curves of samarium-holmium-iron garnet synthesized by coprecipitation

    Directory of Open Access Journals (Sweden)

    Caffarena Valeska da Rocha

    2003-01-01

    Full Text Available An investigation was made into the synthesis and magnetic properties of Sm(3-xHo xFe5O12 (samarium-holmium-iron garnet ferrite, as yet absent from the literature. The material in question was synthesized by co-precipitation, starting from hydrated chlorides of rare-earth elements and ferrous sulfate, and the mixed hydroxide co-precipitate was calcined at 1000 °C. Using PVA as a binder, rectangular cross section-shaped compacts were produced by means of steel-die pressing, drying and sintering from 1200 to 1450 °C. The main conclusions of this study were that the coercive force decreases as the sintering temperature increases, and that the effect of substituting holmium for samarium in SmIG is entirely different from that provided by replacing yttrium by gadolinium in YIG, which is the most important result of this work. An in-depth investigation will be necessary to determine the correlation between microstructure/magnetic properties and ceramic processing variables.

  15. Bone-seeking radiopharmaceuticals as targeted agents of osteosarcoma: samarium-153-EDTMP and radium-223.

    Science.gov (United States)

    Anderson, Peter M; Subbiah, Vivek; Rohren, Eric

    2014-01-01

    Osteosarcoma is a cancer characterized by formation of bone by malignant cells. Routine bone scan imaging with Tc-99m-MDP is done at diagnosis to evaluate primary tumor uptake and check for bone metastases. At time of relapse the Tc-99m-MDP bone scan also provides a specific means to assess formation of bone by malignant osteosarcoma cells and the potential for bone-seeking radiopharmaceuticals to deliver radioactivity directly into osteoblastic osteosarcoma lesions. This chapter will review and compare a bone-seeking radiopharmaceutical that emits beta-particles, samarium-153-EDTMP, with an alpha-particle emitter, radium-223. The charged alpha particles from radium-223 have far more mass and energy than beta particles (electrons) from Sm-153-EDTMP. Because radium-223 has less marrow toxicity and more radiobiological effectiveness, especially if inside the bone forming cancer cell than samarium-153-EDTMP, radium-223 may have greater potential to become widely used against osteosarcoma as a targeted therapy. Radium-223 also has more potential to be used with chemotherapy against osteosarcoma and bone metastases. Because osteosarcoma makes bone and radium-223 acts like calcium, this radiopharmaceutical could possibly become a new targeted means to achieve safe and effective reduction of tumor burden as well as facilitate better surgery and/or radiotherapy for difficult to resect large, or metastatic tumors.

  16. Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

    Science.gov (United States)

    Liu, Peng; Wang, Yunjiao; Wang, Xue; Yang, Chao; Yi, Yanfeng

    2012-11-01

    Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm2O3 nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm2O3) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm2O3 composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm2O3 composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm2O3 composite at a current density of 20 mA cm-2 in a 1.0 M NaNO3 electrolyte solution, a maximum discharge capacity of 771 F g-1 was achieved in a half-cell setup configuration for the PPy/Sm2O3 composites electrode with the potential application to electrode materials for electrochemical capacitors.

  17. Polypyrrole-coated samarium oxide nanobelts: fabrication, characterization, and application in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu Peng, E-mail: pliu@lzu.edu.cn; Wang Yunjiao; Wang Xue; Yang Chao; Yi Yanfeng [College of Chemistry and Chemical Engineering, Lanzhou University, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry (China)

    2012-11-15

    Polypyrrole-coated samarium oxide nanobelts were synthesized by the in situ chemical oxidative surface polymerization technique based on the self-assembly of pyrrole on the surface of the amine-functionalized Sm{sub 2}O{sub 3} nanobelts. The morphologies of the polypyrrole/samarium oxide (PPy/Sm{sub 2}O{sub 3}) nanocomposites were characterized using transmission electron microscope. The UV-vis absorbance of these samples was also investigated, and the remarkable enhancement was clearly observed. The electrochemical behaviors of the PPy/Sm{sub 2}O{sub 3} composites were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge. The results indicated that the PPy/Sm{sub 2}O{sub 3} composite electrode was fully reversible and achieved a very fast Faradaic reaction. After being corrected into the weight percentage of the PPy/Sm{sub 2}O{sub 3} composite at a current density of 20 mA cm{sup -2} in a 1.0 M NaNO{sub 3} electrolyte solution, a maximum discharge capacity of 771 F g{sup -1} was achieved in a half-cell setup configuration for the PPy/Sm{sub 2}O{sub 3} composites electrode with the potential application to electrode materials for electrochemical capacitors.

  18. The effects of Ta on the formation of Ni-silicide in Ni{sub 0.95x}Ta{sub x0.05}/Si systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongwon [Department of Ceramic Engineering, Yonsei University, Seoul (Korea, Republic of); Do, Kihoon [Department of Ceramic Engineering, Yonsei University, Seoul (Korea, Republic of); Ko, Dae-Hong [Department of Ceramic Engineering, Yonsei University, Seoul (Korea, Republic of)]. E-mail: polymetal@empal.com; Choi, Siyoung [Process Development Team, Semiconductor R and D Division, Samsung Electronics Ltd. (Korea, Republic of); Ku, Ja-Hum [Process Development Team, Semiconductor R and D Division, Samsung Electronics Ltd. (Korea, Republic of); Yang, Cheol-Woong [School of Metallurgical and Materials Engineering, Sungkyunkwan University Suwon (Korea, Republic of)

    2004-12-15

    We investigated a comparative study on the silicide formation in the Ni{sub 0.95}Ta{sub 0.05}/Si alloy systems and Ni/Si systems. Ni and Ni{sub 0.95}Ta{sub 0.05} films were deposited on Si(1 0 0) substrate by DC magnetron sputtering and processed at various silicidation temperatures. The sheet resistance of the silicide from the Ni{sub 0.95}Ta{sub 0.05}/Si alloy systems was obtained at lower values than those in pure Ni/Si systems at any temperature. Using RBS and TEM analyses, we confirmed the presence of a Ta rich layer at the top of the Ni-silicide layer and the presence of small amounts of Ta in the silicide layer. The stability of the silicide layer for the Ni{sub 0.95}Ta{sub 0.05} systems is explained by the presence of the Ta rich layer on top of the Ni-silicide layer, as well as by the presence of the small amount of Ta in the Ni-silicide layer. The Ni-silicide using Ni{sub 0.95}Ta{sub 0.05}/Si system displayed a stable sheet resistance value of {approx}5 {omega}/sq which was maintained during the anneal process at 600 deg. C.

  19. Behavior of Samarium III during the sorption process; Comportamiento del Samario-III durante el proceso de sorcion

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E.; Garcia G, N.; Garcia R, G. [ININ, Carr. Mexico-Toluca Km 36.5, Salazar, Estado de Mexico (Mexico)]. e-mail: edo@nuclear.inin.mx

    2004-07-01

    In this work the results of the behavior of samarium in solution are presented, in front of a fine powder of zirconium silicate (zircon). For that which is necessary to characterize the zircon, studying the crystallinity, the morphology, the surface area and the isoelectric point. The behavior of samarium in solution is studied by means of the elaboration of isotherm of sorption, using the technique by lots. One observes that to pH values of nearer to the isoelectric point (pH = 7.23) the process of sorption of the samarium begins, reaching a maximum to near pH at 9. The technique of luminescence is used to determine the concentration of the sipped samarium (phosphorescence) and also to make the speciation of the species formed in the surface of the zircon (phosphorescence). The results can be extrapolated with the plutonium when making the modeling of the migration of alpha emitting coming from the repositories of radioactive waste since both they have similar chemical properties (they are homologous). (Author)

  20. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry in the Region of Samarium, Europium, and Gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, R D; Kelley, K; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of samarium, europium and gadolinium (62 {le} Z {le} 64, 82 {le} N {le} 96).

  1. Pemisahan Unsur Samarium dan Yttrium dari Mineral Tanah Jarang dengan Teknik Membran Cair Berpendukung (Supported Liquid Membrane

    Directory of Open Access Journals (Sweden)

    Amri Amin

    2009-06-01

    Full Text Available he increasing use of rare earth elements in high technology industries needs to be supported by developmental work for the separation of elements. The research objective is fiercely attracting and challenging considering the similarity of bath physical and chemical properties among these elements. The rate separation of samarium and yttrium elements using supported liquid membrane has been studied. Polytetrafluoroethylene (PTFE with pore size of 0.45 µm has been used as the membrane and di(2-ethylhexyl phosphate (D2EHP in hexane has been used as a carrier and nitric acid solution has been used as receiving phase. Result of experiments showed that the best separation rate of samarium and yttrium elements could be obtained at feeding phase of pH 3.0, di(2-ethylhexyl phosphate (D2EHP concentration of 0.3 M, agitation rate of 700 rpm, agitation time of 2 hours, and nitric acid and its solution concentrations of 1.0 M and 0.1 M, respectively. At this condition, separation rates of samarium and yttrium were 64.4 and 67.6%, respectively.   Keywords: liquid membrane, rare earth elements, samarium, yttrium

  2. Study of optical and luminescence properties of silicon — semiconducting silicide — silicon multilayer nanostructures

    Directory of Open Access Journals (Sweden)

    Galkin N.G.

    2017-01-01

    Full Text Available By method of in situ differential spectroscopy it was established that at the formation of monolayer Fe, Cr, Ca, Mg silicide and Mg stannide islands on the atomically clean silicon surface an appearance of loss peaks characteristic for these materials in the energy range of 1.1-2.6 eV is observed. An optimization of growth processes permit to grow monolithic double nanoheterostructures (DNHS with embedded Fe, Cr and Ca nanocrystals, and also polycrystalline DNHS with NC of Mg silicide and Mg stannide and Ca disilicide. By methods of optical spectroscopy and Raman spectroscopy it was shown that embedded NC form intensive peaks in the reflectance spectra at energies up to 2.5 eV and Raman peaks. In DNS with β-FeSi2 NC a photoluminescence and electroluminescence at room temperature were firstly observed.

  3. Development of a fused slurry silicide coating for the protection of tantalum alloys

    Science.gov (United States)

    Packer, C. M.; Perkins, R. A.

    1974-01-01

    Results are reported of a research program to develop a reliable high-performance, fused slurry silicide protective coating for a tantalum-10 tungsten alloy for use at 1427 to 1538 C at 0.1 to 10 torr air pressure under cyclic temperature conditions. A review of silicide coating performance under these conditions indicated that the primary wear-out mode is associated with widening of hairline fissures in the coating. Consideration has been given to modifying the oxidation products that form on the coating surface to provide a seal for these fissures and to minimize their widening. On the basis of an analysis of the phase relationships between silica and various other oxides, a coating having the slurry composition 2.5Mn-33Ti-64.5Si was developed that is effective in the pressure range from 1 to 10 torr.

  4. Effect of Saturation Pressure Difference on Metal–Silicide Nanopowder Formation in Thermal Plasma Fabrication

    Directory of Open Access Journals (Sweden)

    Masaya Shigeta

    2016-03-01

    Full Text Available A computational investigation using a unique model and a solution algorithm was conducted, changing only the saturation pressure of one material artificially during nanopowder formation in thermal plasma fabrication, to highlight the effects of the saturation pressure difference between a metal and silicon. The model can not only express any profile of particle size–composition distribution for a metal–silicide nanopowder even with widely ranging sizes from sub-nanometers to a few hundred nanometers, but it can also simulate the entire growth process involving binary homogeneous nucleation, binary heterogeneous co-condensation, and coagulation among nanoparticles with different compositions. Greater differences in saturation pressures cause a greater time lag for co-condensation of two material vapors during the collective growth of the metal–silicide nanopowder. The greater time lag for co-condensation results in a wider range of composition of the mature nanopowder.

  5. Leakage current and deep levels in CoSi{sub 2} silicided junctions

    Energy Technology Data Exchange (ETDEWEB)

    Codegoni, D. [ST Microelectronics Via Olivetti 2, 20041 Agrate Brianza, Milan (Italy); Carnevale, G.P. [ST Microelectronics Via Olivetti 2, 20041 Agrate Brianza, Milan (Italy); De Marco, C. [ST Microelectronics Via Olivetti 2, 20041 Agrate Brianza, Milan (Italy); Mica, I. [ST Microelectronics Via Olivetti 2, 20041 Agrate Brianza, Milan (Italy); Polignano, M.L. [ST Microelectronics Via Olivetti 2, 20041 Agrate Brianza, Milan (Italy)]. E-mail: marialuisa.polignano@st.com

    2005-12-05

    In this work the leakage current of junctions with a self-aligned cobalt silicide is studied. It is shown that junctions with a self-aligned CoSi{sub 2} layer show a leakage current excess which is strongly reduced by increasing the PAI energy. This indicates that the observed leakage current excess is related to the CoSi{sub 2} formation conditions. The mechanism responsible for the leakage of CoSi{sub 2} junctions is investigated by current versus temperature measurements and by deep level transient spectroscopy. In addition, the role of the mechanical stress is investigated by comparing different isolation structures and by numerical stress calculations. It is concluded that the shallow trench isolation (STI) induced stress and the cobalt silicide formation concur to produce a junction leakage current increase by creating a deep level in silicon located close to midgap. This level can possibly identified with a level ascribed to a point defect excess.

  6. Thermal transport across metal silicide-silicon interfaces: An experimental comparison between epitaxial and nonepitaxial interfaces

    Science.gov (United States)

    Ye, Ning; Feser, Joseph P.; Sadasivam, Sridhar; Fisher, Timothy S.; Wang, Tianshi; Ni, Chaoying; Janotti, Anderson

    2017-02-01

    Silicides are used extensively in nano- and microdevices due to their low electrical resistivity, low contact resistance to silicon, and their process compatibility. In this work, the thermal interface conductance of TiSi2, CoSi2, NiSi, and PtSi are studied using time-domain thermoreflectance. Exploiting the fact that most silicides formed on Si(111) substrates grow epitaxially, while most silicides on Si(100) do not, we study the effect of epitaxy, and show that for a wide variety of interfaces there is no dependence of interface conductance on the detailed structure of the interface. In particular, there is no difference in the thermal interface conductance between epitaxial and nonepitaxial silicide/silicon interfaces, nor between epitaxial interfaces with different interface orientations. While these silicide-based interfaces yield the highest reported interface conductances of any known interface with silicon, none of the interfaces studied are found to operate close to the phonon radiation limit, indicating that phonon transmission coefficients are nonunity in all cases and yet remain insensitive to interfacial structure. In the case of CoSi2, a comparison is made with detailed computational models using (1) full-dispersion diffuse mismatch modeling (DMM) including the effect of near-interfacial strain, and (2) an atomistic Green' function (AGF) approach that integrates near-interface changes in the interatomic force constants obtained through density functional perturbation theory. Above 100 K, the AGF approach significantly underpredicts interface conductance suggesting that energy transport does not occur purely by coherent transmission of phonons, even for epitaxial interfaces. The full-dispersion DMM closely predicts the experimentally observed interface conductances for CoSi2, NiSi, and TiSi2 interfaces, while it remains an open question whether inelastic scattering, cross-interfacial electron-phonon coupling, or other mechanisms could also account for

  7. Effects of the atomic environment on the electron binding energies in samarium

    Energy Technology Data Exchange (ETDEWEB)

    Inoyatov, A.Kh., E-mail: inoyatov@jinr.ru [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Institute of Applied Physics, National University, Tashkent, Republic of Uzbekistan (Uzbekistan); Kovalík, A. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Filosofov, D.V. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Ryšavý, M.; Vénos, D. [Nuclear Physics Institute of the ASCR, CZ-25068 Řež near Prague (Czech Republic); Yushkevich, Yu.V.; Perevoshchikov, L.L. [Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region (Russian Federation); Zhdanov, V.S. [Nuclear Physics Institute, Almaty, Republic of Kazakhstan (Kazakhstan)

    2016-02-15

    Highlights: • Eight different matrices (evaporated and implanted at 30 keV) used. • The greatest average difference in the binding energies amounted to 3.1 ± 0.1 eV. • The presence of trivalent and divalent Sm ions found in some implanted samples. • No significant differences in Sm natural atomic level widths were observed. - Abstract: Effects of the atomic environment on the L{sub 1}, L{sub 2}, L{sub 3}, M{sub 1}, M{sub 2}, M{sub 3}, and N{sub 1} electron binding energies in samarium generated in the electron capture decay of radioactive {sup 149}Eu were investigated by means of the internal conversion electron spectroscopy using the conversion electron spectrum of the 22.5 keV M1 + E2 nuclear transition in the daughter {sup 149}Sm. In this investigation, four pairs of {sup 149}Eu sources prepared by vacuum evaporation deposition and by ion implantation at 30 keV with the use of four different source backing materials, namely polycrystalline carbon, aluminium, gadolinium and platinum foils, were employed. The greatest average difference of (3.1 ± 0.1) eV in the L{sub 1}, L{sub 2}, L{sub 3}, and M{sub 1} subshell electron binding energies was observed between the {sup 149}Eu sources prepared by ion implantation into the aluminium and platinum substrates. On the other hand, minimal differences in the electron binding energies were generally found between samarium generated in the evaporated layer and in the bulk for the individual investigated source backings with the exception of the gadolinium foil. A doublet structure of all investigated conversion electron lines with the average values of 8.1 ± 0.2 eV and 1.5 ± 0.1 for the separation energy and the intensity ratio of the low-energy to high-energy components, respectively, was observed for the {sup 149}Eu sources prepared by ion implantation into the aluminium and carbon foils. This structure was presumably caused by the presence of both the trivalent and divalent Sm ions in the sources. No

  8. An experimental study of the influence of oxygen on silicide formation with tungsten deposited from tungsten hexafluoride

    Science.gov (United States)

    Zhang, S.-L.; Smith, U.; Buchta, R.; Östling, M.

    1991-01-01

    Tungsten disilicide (WSi2) was formed by annealing tungsten films deposited by low-pressure chemical vapor deposition on -silicon substrates. The influence of oxygen on the silicidation rate was studied. Si wafers with different oxygen content in the form of Czochralski, float-zone, and epitaxial wafers were used. Oxygen was also ion implanted into either the silicon substrate or the as-deposited tungsten film. The Rutherford backscattering technique was used to follow the progress of the silicidation. The silicidation rate was found to be dependent on the oxygen content of the Si substrates. The rate was lowest for Czochralski substrates and highest for float-zone substrates. Secondary ion mass spectroscopy was used to study the oxygen and fluorine profiles in the films prior to and after silicidation. Growth of WSi2 was found to be retarded concurrently with a pile-up of fluorine at the tungsten side of the W/WSi2 interface and a gettering of oxygen from the annealing atmosphere at the interface. Growth of WSi2 was then transferred to the tungsten surface. Oxygen implantation into silicon and tungsten, respectively, reduced the rate of silicide formation. Oxygen implantation into tungsten altered the distribution of fluorine and suppressed WSi2 growth at the tungsten surface. The observations led to a conceptual model, which ascribes the retardation in the growth of the inner WSi2 to a``poisoning'' effect caused by the increase of oxygen and fluorine levels at the interface.

  9. Multiphoton laser wave-mixing absorption spectroscopy for samarium using a graphite furnace atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Maniaci, Michael J.; Tong, William G. E-mail: william.tong@sdsu.edu

    2004-07-30

    Nonlinear laser wave-mixing optical technique is presented as a sensitive atomic spectroscopic method for the analysis of rare earth elements using an unmodified commercially available graphite furnace (GF) atomizer. A simple nonplanar backward-scattering degenerate four-wave mixing optical arrangement offers sub-picogram detection sensitivity with sub-Doppler Lorentzian-broadened resolution. Nonlinear wave mixing is an unusually sensitive absorption-based optical method that offers both excellent detection sensitivity and sub-Doppler spectral resolution. A mass detection limit of 0.7 pg and a concentration detection limit of 70 pg/ml are determined for a rare earth element, samarium, using the 429.7-nm excitation line.

  10. Samarium Doped Cerium Oxide Clusters: a Study on the Modulation of Electronic Structure

    Science.gov (United States)

    Topolski, Josey E.; Kafader, Jared O.; Marrero-Colon, Vicmarie; Chick Jarrold, Caroline

    2017-06-01

    Cerium oxide is known for its use in solid oxide fuel cells due to its high ionic conductivity. The doping of trivalent samarium atoms into cerium oxide is known to enhance the ionic conductivity through the generation of additional oxygen vacancies. This study probes the electronic structure of Sm_{x}Ce_{y}O_{z} (x+y=3, z=2-4) anion and neutral clusters. Anion photoelectron spectra of these mixed metal clusters exhibit additional spectral features not present in the previously studied cerium oxide clusters. Density functional theory calculations have been used to aid interpretation of collected spectra. The results of this work can be used to inform the design of materials used for solid oxide fuel cells.

  11. Chelating Ligand-Mediated Hydrothermal Synthesis of Samarium Orthovanadate with Decavanadate as Vanadium Source

    Directory of Open Access Journals (Sweden)

    Quanguo Li

    2013-01-01

    Full Text Available A new ethylenediaminetetraacetic acid- (EDTA- mediated hydrothermal route to prepare chrysanthemum-shaped samarium orthovanadate (SmVO4 nanocrystals with decavanadate (K6V10O28·9H2O as vanadium source has been developed. The present hydrothermal approach is simple and reproducible and employs a relatively mild reaction temperature. The EDTA, pH value, and temperature of the reaction systems play important roles in determining the morphologies and growth process of the SmVO4 products. The products have been characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR, photoluminescence spectra (PL, and UV-Vis spectroscopy.

  12. The Magnetocaloric Effect and Heat Capacity of Suspensions of High-Dispersity Samarium Ferrite

    Science.gov (United States)

    Korolev, V. V.; Aref'ev, I. M.; Ramazanova, A. G.

    2008-02-01

    The magnetocaloric effect and specific heat capacity of an aqueous suspension of samarium ferrite were determined calorimetrically over the temperature range 288-343 K in magnetic fields of 0-0.7 T. The data obtained were used to calculate changes in the magnetic component of the molar heat capacity and entropy of the magnetic phase and changes in the enthalpy of the process under an applied magnetic field. The magnetocaloric effect was found to increase nonlinearly as the magnetic field induction grew. The corresponding temperature dependences contained a maximum at 313 K related to the second-order magnetic phase transition at the Curie point. The field and temperature dependences of heat capacity contained a maximum in fields of 0.4 T and a minimum at the magnetic phase transition temperature.

  13. Preparation of hollow core/shell microspheres of hematite and its adsorption ability for samarium.

    Science.gov (United States)

    Yu, Sheng-Hui; Yao, Qi-Zhi; Zhou, Gen-Tao; Fu, Sheng-Quan

    2014-07-09

    Hollow core/shell hematite microspheres with diameter of ca. 1-2 μm have been successfully achieved by calcining the precursor composite microspheres of pyrite and polyvinylpyrrolidone (PVP) in air. The synthesized products were characterized by a wide range of techniques including powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and Brunauer-Emmett-Teller (BET) gas sorptometry. Temperature- and time-dependent experiments unveil that the precursor pyrite-PVP composite microspheres finally transform into hollow core/shell hematite microspheres in air through a multistep process including the oxidation and sulfation of pyrite, combustion of PVP occluded in the precursor, desulfation, aggregation, and fusion of nanosized hematite as well as mass transportation from the interior to the exterior of the microspheres. The formation of the hollow core/shell microspheres dominantly depends on the calcination temperature under current experimental conditions, and the aggregation of hematite nanocrystals and the core shrinking during the oxidation of pyrite are responsible for the formation of the hollow structures. Moreover, the adsorption ability of the hematite for Sm(III) was also tested. The results exhibit that the hematite microspheres have good adsorption activity for trivalent samarium, and that its adsorption capacity strongly depends on the pH of the solution, and the maximum adsorption capacity for Sm(III) is 14.48 mg/g at neutral pH. As samarium is a typical member of the lanthanide series, our results suggest that the hollow hematite microspheres have potential application in removal of rare earth elements (REEs) entering the water environment.

  14. The influence of the technological parameters on the ionic conductivity of samarium doped ceria thin films

    Directory of Open Access Journals (Sweden)

    Mantas Sriubas

    2015-03-01

    Full Text Available Sm0,20Ce0,80O2 powder was used for the formation of samarium doped cerium oxide (SDC thin films using e-beam. Surface area of powder was 34.9 m2/g and particle size – 0.3-0.5 μm. Thin films were deposited using physical vapor deposition system on SiO2 and Alloy 600 substrates. 2 Å/s – 16 Å/s growth rate and 20 °C – 600 °C substrate temperature were used during the deposition. Ionic conductivity investigation revealed that the maximum ionic conductivity (1.67 S/m has the thin film deposited on 300 °C temperature substrate using 4 Å/s growth rate. Minimum ionic conductivity (0.26 S/m has thin film which was deposited on 20 °C temperature substrate using 8 Å/s growth rate. Vacancy activation energies vary in 0.87 eV – 0.97 eV range. Furthermore the calculations of crystallite size revealed that crystallite size increases with increasing substrate temperature: from 7.50 nm to 46.23 nm on SiO2 substrate and from 9.30 nm to 44.62 nm on Alloy 600 substrate. Molar concentration of samarium in initial evaporated material is 19.38 mol% and varies from 11.37 mol% to 21 mol% in formed thin films depending on technological parameters.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5700

  15. Probing Transition-Metal Silicides as PGM-Free Catalysts for Hydrogen Oxidation and Evolution in Acidic Medium

    Science.gov (United States)

    Mittermeier, Thomas; Madkikar, Pankaj; Wang, Xiaodong; Gasteiger, Hubert A.; Piana, Michele

    2017-01-01

    In this experimental study, we investigate various transition-metal silicides as platinum-group-metal-(PGM)-free electrocatalysts for the hydrogen oxidation reaction (HOR), and for the hydrogen evolution reaction (HER) in acidic environment for the first time. Using cyclic voltammetry in 0.1 M HClO4, we first demonstrate that the tested materials exhibit sufficient stability against dissolution in the relevant potential window. Further, we determine the HOR and HER activities for Mo, W, Ta, Ni and Mo-Ni silicides in rotating disk electrode experiments. In conclusion, for the HOR only Ni2Si shows limited activity, and the HER activity of the investigated silicides is considerably lower compared to other PGM-free HER catalysts reported in the literature. PMID:28773022

  16. Temperature and Stress Simulation of 4H-SiC during Laser-Induced Silicidation for Ohmic Contact Generation

    Directory of Open Access Journals (Sweden)

    Benedikt Adelmann

    2017-12-01

    Full Text Available We report here on the simulation of temperature and stress evolution of 4H-SiC during laser-induced silicidation to locally generate ohmic contacts between the semiconductor and nickel metallization. The simulation is based on optical free carrier absorption, thermal conduction, and thermal radiation. Our results show that, during laser irradiation, similar temperatures and correspondingly similar contact resistances, as compared to conventional oven-driven annealing processes, are achievable, yet with the advantageous potential to limit the temperature treatment spatially to the desired regions for electrical contacts and without the necessity of heating complete wafers. However, due to temperature gradients during local laser silicidation, thermal induced stress appears, which may damage the SiC wafer. Based on the simulated results for temperature and stress increase, we identify an optimized regime for laser-induced local silicidation and compare it to experimental data and observations.

  17. Intercalation synthesis of graphene-capped iron silicide atop Ni(111): Evolution of electronic structure and ferromagnetic ordering

    Energy Technology Data Exchange (ETDEWEB)

    Grebenyuk, G.S. [Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Vilkov, O.Yu.; Rybkin, A.G. [St. Petersburg State University, 199034 St. Petersburg (Russian Federation); Gomoyunova, M.V. [Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Senkovskiy, B.V. [St. Petersburg State University, 199034 St. Petersburg (Russian Federation); II. Physikalisches Institut, Universität zu Köln, D-50937 Cologne (Germany); Usachov, D.Yu. [St. Petersburg State University, 199034 St. Petersburg (Russian Federation); Vyalikh, D.V. [St. Petersburg State University, 199034 St. Petersburg (Russian Federation); Institute of Solid State Physics, Dresden University of Technology, 01062 Dresden (Germany); Molodtsov, S.L. [European XFEL GmbH, 22761 Hamburg (Germany); Institute of Experimental Physics, Technische Universität Bergakademie Freiberg, 09599 Freiberg (Germany); ITMO University, 197101 St. Petersburg (Russian Federation); Pronin, I.I., E-mail: Igor.Pronin@mail.ioffe.ru [Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); ITMO University, 197101 St. Petersburg (Russian Federation)

    2017-01-15

    Highlights: • Evolution of Graphene/Ni system due to intercalation with Fe and Si is studied. • Graphene strongly interacts with the topmost atoms of the intercalated fcc Fe film. • The in-plane ferromagnetic ordering of the film arises after intercalation of 5 ML Fe. • Fe-Si solid solution and Fe{sub 3}Si surface silicide are formed after intercalation of Si. • The capping graphene layer is weakly electronically coupled to the silicide phase. - Abstract: A new method for synthesis of graphene-protected iron silicides has been tested, which consists in formation of graphene on Ni(111) followed by two-step intercalation of the system with Fe and Si. Characterization of the samples was performed in situ by low-energy electron diffraction, angular-resolved photoelectron spectroscopy, core-level photoelectron spectroscopy with synchrotron radiation and magnetic linear dichroism in photoemission of Fe 3p electrons. It is shown, that at 400 °C the intercalation of graphene/Ni(111) with iron occurs in a range up to 14 ML. The graphene layer strongly interacts with the topmost Fe atoms and stabilizes the fcc structure of the film. The in-plane ferromagnetic ordering of the film has a threshold nature and arises after the intercalation of 5 ML Fe due to the thickness-driven spin reorientation transition. Subsequent intercalation of graphene/Fe/Ni(111) with Si leads to the formation of the inhomogeneous system consisted of intercalated and nonintercalated areas. The intercalated islands coalesce at 2 ML Si when a Fe-Si solid solution covered with the Fe{sub 3}Si surface silicide is formed. The Fe{sub 3}Si silicide is ferromagnetic and has an ordered (√3 × √3)R30° structure. The graphene layer is weakly electronically coupled to the silicide phase keeping its remarkable properties ready for use.

  18. Formation of Core-Shell Nanoparticles Composed of Magnetite and Samarium Oxide in Magnetospirillum magneticum Strain RSS-1.

    Science.gov (United States)

    Shimoshige, Hirokazu; Nakajima, Yoshikata; Kobayashi, Hideki; Yanagisawa, Keiichi; Nagaoka, Yutaka; Shimamura, Shigeru; Mizuki, Toru; Inoue, Akira; Maekawa, Toru

    2017-01-01

    Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) or greigite (Fe3S4) particles in the cells. Recently, several studies have shown some possibilities of controlling the biomineralization process and altering the magnetic properties of magnetosomes by adding some transition metals to the culture media under various environmental conditions. Here, we successfully grow Magnetospirillum magneticum strain RSS-1, which are isolated from a freshwater environment, and find that synthesis of magnetosomes are encouraged in RSS-1 in the presence of samarium and that each core magnetic crystal composed of magnetite is covered with a thin layer of samarium oxide (Sm2O3). The present results show some possibilities of magnetic recovery of transition metals and synthesis of some novel structures composed of magnetic particles and transition metals utilizing MTB.

  19. Formation, optical properties, and electronic structure of thin Yb silicide films on Si(111)

    Science.gov (United States)

    Galkin, N. G.; Maslov, A. M.; Polyarnyi, V. O.

    2005-06-01

    Continuous very thin (2.5-3.0 nm) and thin (16-18 nm) ytterbium suicide films with some pinhole density (3×107- 1×108 cm-2) have been formed on Si(111) by solid phase epitaxy (SPE) and reactive deposition epitaxy (RDE) growth methods on templates. The stoichiometric ytterbium suicide (YbSi2) formation has shown in SPE grown films by AES and EELS data. Very thin Yb suicide films grown by RDE method had the silicon enrichment in YbSi2 suicide composition. The analysis of LEED data and AFM imaging has shown that ytterbium suicide films had non-oriented blocks with the polycrystalline structure. The analysis of scanning region length dependencies of the root mean square roughness deviation (σR(L)) for grown suicide films has shown that the formation of ytterbium suicide in SPE and RDE growth methods is determined by the surface diffusion of Yb atoms during the three-dimensional growth process. Optical functions (n, k, α, ɛ1, ɛ2, Im ɛ1-1, neff, ɛeff) of ytterbium silicide films grown on Si(1 1 1) have been calculated from transmittance and reflectance spectra in the energy range of 0.1-6.2 eV. Two nearly discrete absorption bands have been observed in the electronic structure of Yb silicide films with different composition, which connected with interband transitions on divalent and trivalent Yb states. It was established that the reflection coefficient minimum in R-spectra at energies higher 4.2 eV corresponds to the state density minimum in Yb suicide between divalent and trivalent Yb states. It was shown from optical data that Yb silicide films have the semi-metallic properties with low state densities at energies less 0.4 eV and high state densities at 0.5-2.5 eV.

  20. Combustion synthesis of molybdenum silicides and borosilicides for ultrahigh-temperature structural applications

    Science.gov (United States)

    Alam, Mohammad Shafiul

    Molybdenum silicides and borosilicides are promising structural materials for gas-turbine power plants. A major challenge, however, is to simultaneously achieve high oxidation resistance and acceptable mechanical properties at high temperatures. For example, molybdenum disilicide (MoSi2) has excellent oxidation resistance and poor mechanical properties, while Mo-rich silicides such as Mo5Si3 (called T 1) have much better mechanical properties but poor oxidation resistance. One approach is based on the fabrication of MoSi2-T 1 composites that combine high oxidation resistance of MoSi2 and good mechanical properties of T1. Another approach involves the addition of boron to Mo-rich silicides for improving their oxidation resistance through the formation of a borosilicate surface layer. In particular, Mo 5SiB2 (called T2) phase is considered as an attractive material. In the thesis, MoSi2-T1 composites and materials based on T2 phase are obtained by mechanically activated SHS. Use of SHS compaction (quasi-isostatic pressing) significantly improves oxidation resistance of the obtained MoSi2-T1 composites. Combustion of Mo-Si-B mixtures for the formation of T2 phase becomes possible if the composition is designed for the addition of more exothermic reactions leading to the formation of molybdenum boride. These mixtures exhibit spin combustion, the characteristics of which are in good agreement with the spin combustion theory. Oxidation resistance of the obtained Mo-Si-B materials is independent on the concentration of Mo phase in the products so that the materials with a higher Mo content are preferable because of better mechanical properties. Also, T2 phase has been obtained by the chemical oven combustion synthesis technique.

  1. X-ray photoemission spectromicroscopy of titanium silicide formation in patterned microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.; Solak, H.; Cerrina, F. [Univ. of Wisconsin-Madison, Stoughton, WI (United States)] [and others

    1997-04-01

    Titanium silicide has the lowest resistivity of all the refractory metal silicides and has good thermal stability as well as excellent compatibility with Al metallization. It is used as an intermediate buffer layer between W vias and the Si substrate to provide good electrical contact in ULSI technology, whose submicron patterned features form the basis of the integrated circuits of today and tomorrow, in the self aligned silicide (salicide) formation process. TiSi{sub 2} exists in two phases: a metastable C49 base-centered orthorhombic phase with specific resistivity of 60-90 {mu}{Omega}-cm that is formed at a lower temperature (formation anneal) and the stable 12-15 {mu}{Omega}-cm resistivity face-centered orthorhombic C54 phase into which C49 is transformed with a higher temperature (conversion anneal) step. C54 is clearly the target for low resistivity VLSI interconnects. However, it has been observed that when dimensions shrink below 1/mic (or when the Ti thickness drops below several hundred angstroms), the transformation of C49 into C54 is inhibited and agglomeration often occurs in fine lines at high temperatures. This results in a rise in resistivity due to incomplete transformation to C54 and because of discontinuities in the interconnect line resulting from agglomeration. Spectromicroscopy is an appropriate tool to study the evolution of the TiSi2 formation process because of its high resolution chemical imaging ability which can detect bonding changes even in the absence of changes in the relative amounts of species and because of the capability of studying thick {open_quotes}as is{close_quotes} industrial samples.

  2. In situ, real-time characterization of silicide nanostructure coarsening dynamics by photo-electron emission microscopy

    Science.gov (United States)

    Zeman, Matthew Casimir

    Photo-electron emission microscopy (PEEM) was used to observe the growth and coarsening dynamics of transition metal (TM) silicide and rare earth (RE) silicide nanostructures on silicon surfaces in real-time with high lateral resolution during in situ annealing. Evidence was obtained indicating that the coarsening of the silicide islands is strongly influenced by local variations in the size, shape, and number of nanostructures on the surface. The titanium, hafnium, and zirconium silicide nanostructures were observed to grow via Ostwald ripening and attractive migration and coalescence (AMC) at temperatures as high as ~1200°C. Ostwald ripening is a classic coarsening process in which larger nanostructures grow at the expense of smaller surrounding structures as per the Gibbs-Thompson relation. Attractive migration and coalescence is a newly discovered coarsening pathway where nearby islands are observed to migrate attractively towards each other and subsequently coalesce in response to local adatom concentration variations on the surface. A shape distortion of the normally compact and rounded TM silicide islands has been observed during these coarsening processes. The shape distortion suggests that the nanostructures are exchanging mass with each other via diffusion limited processes and these observations support the AMC model. The dysprosium and erbium silicide nanostructures exhibit a distinct faceted morphology and primarily coarsen via Ostwald ripening. The RE silicides form highly elongated nanowires and compact rectangular nanostructures on Si(001) and triangular or hexagonal structures on Si(111). We show that the wires are metastable structures which decay in favor of the larger rectangular islands at high temperatures. Additionally, the rectangular shape and faceted morphology of the RE silicide nanostructures strongly influences their coarsening dynamics. A separate PEEM study explored the thermal stability of thin films of TM oxides (TiO2, ZrO2, HfO2

  3. Current enhancement in crystalline silicon photovoltaic by low-cost nickel silicide back contact

    KAUST Repository

    Bahabry, R. R.

    2016-11-30

    We report short circuit current (Jsc) enhancement in crystalline silicon (C-Si) photovoltaic (PV) using low-cost Ohmic contact engineering by integration of Nickel mono-silicide (NiSi) for back contact metallization as an alternative to the status quo of using expensive screen printed silver (Ag). We show 2.6 mA/cm2 enhancement in the short circuit current (Jsc) and 1.2 % increment in the efficiency by improving the current collection due to the low specific contact resistance of the NiSi on the heavily Boron (B) doped Silicon (Si) interface.

  4. Evaluation of anomalies during nickel and titanium silicide formation using the effective heat of formation mode

    CSIR Research Space (South Africa)

    Pretorius, R

    1993-11-01

    Full Text Available stream_source_info pretorius_1993.pdf.txt stream_content_type text/plain stream_size 39978 Content-Encoding ISO-8859-1 stream_name pretorius_1993.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Materials Chemistry... and Physics, 36 (1993) 31-38 31 Evaluation of anomalies during nickel and titanium silicide formation using the effective heat of formation model R. Pretorius, C.C. Theron IonSolid Znteraction Division, Van de H.A. Ras and T...

  5. On the structural and electronic properties of Ir-silicide nanowires on Si(001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Fatima,; Hossain, Sehtab; Mohottige, Rasika; Oncel, Nuri, E-mail: gulseren@fen.bilkent.edu.tr, E-mail: nuri.oncel@und.edu [Department of Physics and Astrophysics, University of North Dakota, Grand Forks, North Dakota 58202 (United States); Can Oguz, Ismail; Gulseren, Oguz, E-mail: gulseren@fen.bilkent.edu.tr, E-mail: nuri.oncel@und.edu [Department of Physics, Bilkent University, Ankara (Turkey); Çakır, Deniz [Department of Physics, University of Antwerp, Antwerp 2610 (Belgium)

    2016-09-07

    Iridium (Ir) modified Silicon (Si) (001) surface is studied with Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and Density Functional Theory (DFT). A model for Ir-silicide nanowires based on STM images and ab-initio calculations is proposed. According to our model, the Ir adatom is on the top of the substrate dimer row and directly binds to the dimer atoms. I-V curves measured at 77 K shows that the nanowires are metallic. DFT calculations confirm strong metallic nature of the nanowires.

  6. Co-reduction of aluminium and lanthanide ions in molten fluorides: Application to cerium and samarium extraction from nuclear wastes

    Energy Technology Data Exchange (ETDEWEB)

    Gibilaro, M. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France); Massot, L. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France)], E-mail: massot@chimie.ups-tlse.fr; Chamelot, P.; Taxil, P. [Laboratoire de Genie Chimique UMR 5503, Departement Procedes Electrochimiques, Universite de Toulouse, 31062 Toulouse Cedex 9 (France)

    2009-09-01

    This work concerns the method of co-reduction process with aluminium ions in LiF-CaF{sub 2} medium (79-21 mol.%) on tungsten electrode for cerium and samarium extraction. Electrochemical techniques such as cyclic and square wave voltammetries, and potentiostatic electrolyses were used to study the co-reduction of CeF{sub 3} and SmF{sub 3} with AlF{sub 3}. For each of these elements, specific peaks of Al-Ce and Al-Sm alloys formation were observed by voltammetry as well as peaks of pure cerium and aluminium, and pure samarium and aluminium respectively. The difference of potential measured between the solvent reduction and the alloy formation suggests expecting an extraction efficiency of 99.99% of each lanthanide by the process. Different intermetallic compounds were obtained for different potentiostatic electrolysis and were characterised by Scanning Electron Microscopy with EDS probe. The validity of the process was verified by carrying out cerium and samarium extractions in the form of Al-Ln alloy; the extraction efficiency was 99.5% for Ce(III) and 99.4% for Sm(III)

  7. Structural and luminescence properties of samarium doped lead alumino borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Kaur, Simranpreet; Singh, D. P.; Kaur, Puneet

    2017-11-01

    The study reports the effect of samarium concentration on the physical, structural and spectroscopic characteristics of samarium doped lead alumino borate glasses having composition 20PbO-(10-x)Al2O3-70B2O3-xSm2O3; x = 0.1, 0.5, 1.0 and 2.0 mol %. The glasses were fabricated by conventional melt-quenching technique and then characterized by XRD, FTIR, optical absorption and fluorescence spectra. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. FTIR spectra indicate the presence of BO3, BO4, AlO6 and a few other structural groups. Various physical properties such as density, molar volume, refractive index, rare earth ion concentration, boron-boron distance and polarizability etc. were determined using conventional methods and standard formulae. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The value of Ω2 was found to be highest for glass with 1 mol% Sm2O3 and attributed to the asymmetry of the ligand field at the rare earth ion site and the rare earth oxygen (Sm-O) covalency. The calculated intensity parameters and fluorescence spectra were further used to predict the radiative transition probability (A), radiative lifetime (τR), branching ratio (βR), peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σ) for the characteristic 4G5/2 → 6H5/2, 6H7/2 and 6H9/2 transitions of the Sm3+ ion. Concentration quenching was observed for 2 mol% concentration of Sm2O3 and ascribed to energy transfer through various cross-relaxation channels between Sm3+ ions. Reasonably high values of branching ratios and stimulated emission cross-section for the prepared glasses points towards their utility in the development of visible lasers emitting in the reddish-orange spectral region. However, the glass with 1 mol% Sm2O3 was found to show better radiative properties.

  8. Impact of Nickel silicide Rear Metallization on Series Resistance of Crystalline Silicon Solar Cells

    KAUST Repository

    Bahabry, Rabab R

    2018-01-11

    The Silicon-based solar cell is one of the most important enablers toward high efficiency and low-cost clean energy resource. Metallization of silicon-based solar cells typically utilizes screen printed silver-Aluminium (Ag-Al) which affects the optimal electrical performance. To date, metal silicide-based ohmic contacts are occasionally used as an alternative candidate only to the front contact grid lines in crystalline silicon (c-Si) based solar cells. In this paper, we investigate the electrical characteristics of nickel mono-silicide (NiSi)/Cu-Al ohmic contact on the rear side of c-Si solar cells. We observe a significant enhancement in the fill factor of around 6.5% for NiSi/Cu-Al rear contacts leading to increasing the efficiency by 1.2% compared to Ag-Al. This is attributed to the improvement of the parasitic resistance in which the series resistance decreased by 0.737 Ω.cm². Further, we complement experimental observation with a simulation of different contact resistance values, which manifests NiSi/Cu-Al rear contact as a promising low-cost metallization for c-Si solar cells with enhanced efficiency.

  9. Magnesium and Manganese Silicides For Efficient And Low Cost Thermo-Electric Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, Sudhir B. [Brimrose Technology Corporation; Kutcher, Susan W. [Brimrose Technology Corporation; Rosemeier, Cory A. [Brimrose Technology Corporation; Mayers, David [Brimrose Technology Corporation; Singh, Jogender [Pennsylvania State University

    2013-12-02

    Thermoelectric Power Generation (TEPG) is the most efficient and commercially deployable power generation technology for harvesting wasted heat from such things as automobile exhausts, industrial furnaces, and incinerators, and converting it into usable electrical power. We investigated the materials magnesium silicide (Mg2Si) and manganese silicide (MnSi) for TEG. MgSi2 and MnSi are environmentally friendly, have constituent elements that are abundant in the earth's crust, non-toxic, lighter and cheaper. In Phase I, we successfully produced Mg2Si and MnSi material with good TE properties. We developed a novel technique to synthesize Mg2Si with good crystalline quality, which is normally very difficult due to high Mg vapor pressure and its corrosive nature. We produced n-type Mg2Si and p-type MnSi nanocomposite pellets using FAST. Measurements of resistivity and voltage under a temperature gradient indicated a Seebeck coefficient of roughly 120 V/K on average per leg, which is quite respectable. Results indicated however, that issues related to bonding resulted in high resistivity contacts. Determining a bonding process and bonding material that can provide ohmic contact from room temperature to the operating temperature is an essential part of successful device fabrication. Work continues in the development of a process for reproducibly obtaining low resistance electrical contacts.

  10. Silicon-germanium and platinum silicide nanostructures for silicon based photonics

    Science.gov (United States)

    Storozhevykh, M. S.; Dubkov, V. P.; Arapkina, L. V.; Chizh, K. V.; Mironov, S. A.; Chapnin, V. A.; Yuryev, V. A.

    2017-05-01

    This paper reports a study of two types of silicon based nanostructures prospective for applications in photonics. The first ones are Ge/Si(001) structures forming at room temperature and reconstructing after annealing at 600°C. Germanium, being deposited from a molecular beam at room temperature on the Si(001) surface, forms a thin granular film composed of Ge particles with sizes of a few nanometers. A characteristic feature of these films is that they demonstrate signs of the 2 x 1 structure in their RHEED patterns. After short-term annealing at 600°C under the closed system conditions, the granular films reconstruct to heterostructures consisting of a Ge wetting layer and oval clusters of Ge. A mixed type c(4x2) + p(2x2) reconstruction typical to the low-temperature MBE (Tgr class of materials is one of the friendliest to silicon technology. But as silicide film thickness reaches a few nanometers, low resistivity becomes of primary importance. Pt3Si has the lowest sheet resistance among the Pt silicides. However, the development of a process of thin Pt3Si films formation is a challenging task. This paper describes formation of a thin Pt3Si/Pt2Si structures at room temperature on poly-Si films. Special attention is paid upon formation of poly-Si and amorphous Si films on Si3N4 substrates at low temperatures.

  11. Preparation and properties of sputtered nitrogen-doped cobalt silicide film

    Energy Technology Data Exchange (ETDEWEB)

    Ting, J.-H.; Shiau, S.-H.; Chen, Y.-J.; Pan, F.-M.; Wong Harianto; Pu, Gibson M.; Kung, C.-Y

    2004-12-01

    It is the purpose of this study to develop tough hinge material for the application of the torsional springs. Nitrogen-doped cobalt silicide (CoSi{sub x}N{sub y}) film is sputtered from cobalt silicide (CoSi{sub 2}) target in Ar/N{sub 2} discharge. Stress and sheet resistance of CoSi{sub x}N{sub y} film are two major properties to be evaluated. Taguchi method is practiced in reactive sputtering deposition of CoSi{sub x}N{sub y} film. Process pressure is most critical to the CoSi{sub x}N{sub y} film stress and the optimum condition of 1000 W, 0.8 Pa, and 20% N{sub 2} flow ratio, indeed results in low tensile CoSi{sub x}N{sub y} film stress, about 54. MPa. Reannealing process indicates that stability of CoSi{sub x}N{sub y} film is attained after first annealing process. Stress hysteresis behaviors of CoSi{sub x} and CoSi{sub x}N{sub y} films resemble that of metal film with a complete elastic manner in the second stage of heating and cooling. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses suggest that toughness and strength of the film is achievable. It is concluded that CoSi{sub x}N{sub y} film as a hinge material is feasible.

  12. Prediction of Stable Ruthenium Silicides from First-Principles Calculations: Stoichiometries, Crystal Structures, and Physical Properties.

    Science.gov (United States)

    Zhang, Chuanzhao; Kuang, Xiaoyu; Jin, Yuanyuan; Lu, Cheng; Zhou, Dawei; Li, Peifang; Bao, Gang; Hermann, Andreas

    2015-12-09

    We present results of an unbiased structure search for stable ruthenium silicide compounds with various stoichiometries, using a recently developed technique that combines particle swarm optimization algorithms with first-principles calculations. Two experimentally observed structures of ruthenium silicides, RuSi (space group P2(1)3) and Ru2Si3 (space group Pbcn), are successfully reproduced under ambient pressure conditions. In addition, a stable RuSi2 compound with β-FeSi2 structure type (space group Cmca) was found. The calculations of the formation enthalpy, elastic constants, and phonon dispersions demonstrate the Cmca-RuSi2 compound is energetically, mechanically, and dynamically stable. The analysis of electronic band structures and densities of state reveals that the Cmca-RuSi2 phase is a semiconductor with a direct band gap of 0.480 eV and is stabilized by strong covalent bonding between Ru and neighboring Si atoms. On the basis of the Mulliken overlap population analysis, the Vickers hardness of the Cmca structure RuSi2 is estimated to be 28.0 GPa, indicating its ultra-incompressible nature.

  13. Preliminary investigations on the use of uranium silicide targets for fission Mo-99 production

    Energy Technology Data Exchange (ETDEWEB)

    Cols, H.; Cristini, P.; Marques, R.

    1997-08-01

    The National Atomic Energy Commission (CNEA) of Argentine Republic owns and operates an installation for production of molybdenum-99 from fission products since 1985, and, since 1991, covers the whole national demand of this nuclide, carrying out a program of weekly productions, achieving an average activity of 13 terabecquerel per week. At present they are finishing an enlargement of the production plant that will allow an increase in the volume of production to about one hundred of terabecquerel. Irradiation targets are uranium/aluminium alloy with 90% enriched uranium with aluminium cladding. In view of international trends held at present for replacing high enrichment uranium (HEU) for enrichment values lower than 20 % (LEU), since 1990 the authors are in contact with the RERTR program, beginning with tests to adapt their separation process to new irradiation target conditions. Uranium silicide (U{sub 3}Si{sub 2}) was chosen as the testing material, because it has an uranium mass per volume unit, so that it allows to reduce enrichment to a value of 20%. CNEA has the technology for manufacturing miniplates of uranium silicide for their purposes. In this way, equivalent amounts of Molybdenum-99 could be obtained with no substantial changes in target parameters and irradiation conditions established for the current process with Al/U alloy. This paper shows results achieved on the use of this new target.

  14. Plasma-enhanced deposition and processing of transition metals and transition metal silicides for VLSI

    Science.gov (United States)

    Hess, D. W.

    1986-05-01

    Radiofrequency (rf) discharges have been used to deposit films of tungsten, molybdenum and titanium silicide. As-deposited tungsten films, from tungsten hexafluoride and hydrogen source gases, were metastable (beta W), with significant (>1 atomic percent) fluorine incorporation. Film resistivities were 40-55 micro ohm - cm due to the beta W, but dropped to about 8 micro ohm cm after a short heat treatment at 700 C which resulted in a phase transition to alpha W (bcc form). The high resistivity (>10,000 micro ohm) associated with molybdenum films deposited from molybdenum hexafluoride and hydrogen appeared to be a result of the formation of molybdenum trifluoride in the deposited material. Titanium silicide films formed from a discharge of titanium tetrachloride, silane, and hydrogen, displayed resistivities of about 150 micro ohm cm, due to small amounts of oxygen and chlorine incorporated during deposition. Plasma etching studies of tungsten films with fluorine containing gases suggest that the etchant species for tungsten in these discharges are fluorine atoms.

  15. Two-dimensional electronic structure of dysprosium silicide nanowires on Si(557)

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Martina; Loeser, Karolin; Pruskil, Gerd; Daehne, Mario [Institute of Solid State Physics, Technical University Berlin (Germany); Stojanov, Petar; Huwald, Eric; Riley, John [School of Physics, La Trobe University, Bundoora, VIC (Australia)

    2008-07-01

    Rare earth silicide nanostructures are of high interest because of their extremely low Schottky barriers on n-Si(111) and the formation of nanowires with one-dimensional metallicity on Si(001). In this work, the self-organized growth of monolayer-thick dysprosium silicide nanowires on Si(557) has been studied by scanning tunnelling microscopy and angle-resolved photoelectron spectroscopy. The bare Si(557) surface is characterized by (111) and (112) facets. Accordingly, we observed the nanowires forming on the (111) facets. For coverages of 2A dysprosium, nanowire lengths exceeding 1{mu}m and widths around 5 nm were found. Their electronic structure shows a strong dispersion both parallel and perpendicular to the nanowires, which is assigned to the band structure of DySi{sub 2} monolayers on Si(111). At higher coverages similar nanowires are observed at the (111) facets, which show characteristic structural properties of the multilayer growth and also the Dy{sub 3}Si{sub 5} multilayer band structure.

  16. Fabrication of Ni-silicide/Si heterostructured nanowire arrays by glancing angle deposition and solid state reaction

    Science.gov (United States)

    2013-01-01

    This work develops a method for growing Ni-silicide/Si heterostructured nanowire arrays by glancing angle Ni deposition and solid state reaction on ordered Si nanowire arrays. Samples of ordered Si nanowire arrays were fabricated by nanosphere lithography and metal-induced catalytic etching. Glancing angle Ni deposition deposited Ni only on the top of Si nanowires. When the annealing temperature was 500°C, a Ni3Si2 phase was formed at the apex of the nanowires. The phase of silicide at the Ni-silicide/Si interface depended on the diameter of the Si nanowires, such that epitaxial NiSi2 with a {111} facet was formed at the Ni-silicide/Si interface in Si nanowires with large diameter, and NiSi was formed in Si nanowires with small diameter. A mechanism that is based on flux divergence and a nucleation-limited reaction is proposed to explain this phenomenon of size-dependent phase formation. PMID:23663726

  17. Formation of Mg silicides on amorphous Si. Origin and role of high pressure in the film growth

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, S.A. [Institute for Automation and Control Processes, 5 Radio St., Vladivostok 690041 (Russian Federation); Far Eastern Federal University, Physics Dpt., 8 Sukhanova Str., Vladivostok 690950 (Russian Federation); Gouralnik, A.S., E-mail: fungoeson@mail.ru [Institute for Automation and Control Processes, 5 Radio St., Vladivostok 690041 (Russian Federation); Galkin, N.G. [Institute for Automation and Control Processes, 5 Radio St., Vladivostok 690041 (Russian Federation); Far Eastern Federal University, Physics Dpt., 8 Sukhanova Str., Vladivostok 690950 (Russian Federation); Galkin, K.N. [Institute for Automation and Control Processes, 5 Radio St., Vladivostok 690041 (Russian Federation); Gutakovski, A.K.; Neklyudova, M.A. [Rzhanov Institute of Semiconductor Physics, Siberian Branch Russian Academy of Sciences, Lavrentiev Av., Novosibirsk (Russian Federation)

    2014-12-15

    Growth of Mg film on amorphous Si (a-Si) at room temperature in UHV conditions was studied in situ with optical differential reflection spectroscopy and electron energy loss spectroscopy. The phase composition of the film was also studied by high-resolution transmission electron microscopy. The mechanism of silicide film growth on a-Si is considered. The origin of internal stress within the growing film and its role in the silicide film growth process are discussed. Due to high pressure occurring within the growing film, the first phase to form is the hexagonal silicide phase h-Mg{sub 2}Si. According to the DRS data, the phase h-Mg{sub 2}Si is semiconducting. The new peak in the differential reflectance spectrum is assigned to the h-Mg{sub 2}Si. At later stages of Mg deposition the cubic silicide phase c-Mg{sub 2}Si grows. - Highlights: • The film growth by UHV deposition of Mg on amorphous Si layer was studied. • Two Mg{sub 2}Si phases, hexagonal and cubic, were formed on amorphous Silicon. • The metastable h-Mg{sub 2}Si forms first, due to very high stress inside the film. • The stress is induced by chemical forces during intermixing of Mg with Si. • The film growth stages are clearly seen by Differential Reflectance Spectroscopy.

  18. Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology.

    Science.gov (United States)

    Kumar Dalapati, Goutam; Masudy-Panah, Saeid; Kumar, Avishek; Cheh Tan, Cheng; Ru Tan, Hui; Chi, Dongzhi

    2015-12-03

    This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm(2), and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p(+-)n homojunction through the formation of re-grown crystalline silicon layer (~5-10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method.

  19. X-ray Induced Luminescence Spectroscopy of Samarium Doped Barium Sulfate Prepared by Sintering Method

    Science.gov (United States)

    Kumeda, T.; Maeda, K.; Shirano, Y.; Fujiwara, K.; Sakai, K.; Ikari, T.

    2015-06-01

    X-ray induced luminescence (XL) properties of phosphor materials made of samarium doped barium sulfate have been investigated. The samples were prepared by sintering method heated at 900-1250 °C for 3 hours in air from the mixture of BaSO4 and Sm2O3. The concentration of Sm were prepared from 0.01-6 at.%. In as-prepared sample, the Sm3+ was detected by photoluminescence (PL). The PL intensity is maximum about 2 at.% with Sm, and then starts decreasing. The PL intensity showed concentration quenching. The XL observed Sm2+ and Sm3+ ions. The XL was shown from the sample sintered up to 1200 °C. The XL intensity increased with Sm concentration up to 1 at.%. The intensity was almost constant larger than 1 at.% Sm. These concentration dependences is different since the X-ray energy absorbed to the host material at once, and the energy transferred to both Sm3+ and Sm2+ ions. Sm doped BaSO4 is found a host for XL phosphor materials.

  20. High-κ Samarium-Based Metal-Organic Framework for Gate Dielectric Applications.

    Science.gov (United States)

    Pathak, Abhishek; Chiou, Guan Ru; Gade, Narsinga Rao; Usman, Muhammad; Mendiratta, Shruti; Luo, Tzuoo-Tsair; Tseng, Tien Wen; Chen, Jenq-Wei; Chen, Fu-Rong; Chen, Kuei-Hsien; Chen, Li-Chyong; Lu, Kuang-Lieh

    2017-07-05

    The self-assembly of a samarium-based metal-organic framework [Sm2(bhc)(H2O)6]n (1) in good yield was achieved by reacting Sm(NO3)3·6H2O with benzenehexacarboxylic acid (bhc) in a mixture of H2O-EtOH under hydrothermal conditions. A structural analysis showed that compound 1 crystallized in a space group of Pnmn and adopted a 3D structure with (4,8) connected nets. Temperature dependent dielectric measurements showed that compound 1 behaves as a high dielectric material with a high dielectric constant (κ = 45.1) at 5 kHz and 310 K, which is comparable to the values for some of the most commonly available dielectric inorganic metal oxides such as Sm2O3, Ta2O5, HfO2, and ZrO2. In addition, electrical measurements of 1 revealed an electrical conductivity of about 2.15 × 10-7 S/cm at a frequency of 5 kHz with a low leakage current (Ileakage = 8.13 × 10-12 Amm-2). Dielectric investigations of the Sm-based MOF provide an effective path for the development of high dielectric materials in the future.

  1. Pyroelectric properties and electrical conductivity in samarium doped BiFeO 3 ceramics

    KAUST Repository

    Yao, Yingbang

    2012-06-01

    Samarium (Sm 3+) doped BiFeO 3 (BFO) ceramics were prepared by a modified solid-state-reaction method which adopted a rapid heating as well as cooling during the sintering process. The pyroelectric coefficient increased from 93 to 137 μC/m 2 K as the Sm 3+ doping level increased from 1 mol% to 8 mol%. Temperature dependence of the pyroelectric coefficient showed an abrupt decrease above 80 °C in all samples, which was associated with the increase of electrical conductivity with temperature. This electrical conduction was attributed to oxygen vacancy existing in the samples. An activation energy of ∼0.7 eV for the conduction process was found to be irrespective of the Sm 3+ doping level. On the other hand, the magnetic Néel temperature (T N) decreased with increasing Sm 3+ doping level. On the basis of our results, the effects of Sm doping level on the pyroelectric and electrical properties of the BFO were revealed. © 2011 Elsevier Ltd. All rights reserved.

  2. Characterization of luminescent samarium doped HfO{sub 2} coatings synthesized by spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Chacon-Roa, C [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Guzman-Mendoza, J [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Aguilar-Frutis, M [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, Legaria 694, Col. Irrigacion, C.P. 11500, Mexico D.F. (Mexico); Garcia-Hipolito, M [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360 Coyoacan 04510, Mexico, D.F. (Mexico); Alvarez-Fragoso, O [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360 Coyoacan 04510, Mexico, D.F. (Mexico); Falcony, C [Departamento de Fisica, CINVESTAV-IPN, A. P. 14-740, 07000 Mexico D.F. (Mexico)

    2008-01-07

    Trivalent samarium (Sm{sup 3+}) doped hafnium oxide (HfO{sub 2}) films were deposited using the spray pyrolysis deposition technique. The films were deposited on Corning glass substrates at temperatures ranging from 300 to 550 deg. C using chlorides as raw materials. Films, mostly amorphous, were obtained when deposition temperatures were below 350 deg. C. However, for temperatures higher than 400 deg. C, the films became polycrystalline, presenting the HfO{sub 2} monoclinic phase. Scanning electron microscopy of the films revealed a rough surface morphology with spherical particles. Also, electron energy dispersive analysis was performed on these films. The photoluminescence and cathodoluminescence characteristics of the HfO{sub 2} : SmCl{sub 3} films, measured at room temperature, exhibited four main bands centred at 570, 610, 652 and 716 nm, which are due to the well-known intra-4f transitions of the Sm{sup 3+} ion. It was found that the overall emission intensity rose as the deposition temperature was increased. Furthermore, a concentration quenching of the luminescence intensity was also observed.

  3. Samarium-153 EDTMP for metastatic bone pain palliation: the impact of europium impurities.

    Science.gov (United States)

    Kalef-Ezra, J A; Valakis, S T; Pallada, S

    2015-02-01

    To evaluate the impact on the radiation protection policies of the radiocontaminants in Samarium-153 ethylenediamine tetramethylene phosphonate ((153)Sm-EDTMP). The internal contamination of patients treated with (153)Sm-EDMTP for palliation of painful disseminated multiple bone metastases due to long-lived impurities was assessed by direct measurements. These measurements were coupled with dose-rate measurements close to their bodies and spectroscopic analysis of the residual activity in post-treatment radiopharmaceutical vials. Whole-body counting carried out in six patients showed a 30-81-kBq europium -152 plus europium-154 contamination. The 0.85 mean (152)Eu- to -(154)Eu activity ratio obtained by direct counting was similar to that assessed by analysis of post-treatment residual activities in twelve radiopharmaceutical vials following radiopharmaceutical injection. The long-lived radiocontaminants in the patient's bodies and the treatment wastes require modifications of the applicable radiation protection policies. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. Luminescence of trivalent samarium ions in silver and tin co-doped aluminophosphate glass

    Science.gov (United States)

    Jiménez, José A.; Lysenko, Sergiy; Liu, Huimin; Sendova, Mariana

    2011-06-01

    This work presents the spectroscopic properties of trivalent samarium ions in a melt-quenched aluminophosphate glass containing silver and tin. Addition of 4 mol% of each Ag 2O and SnO into the glass system with 2 mol% Sm 2O 3 results in Sm 3+ ions luminescence under non-resonant UV excitation owing to energy transfer from single silver ions and/or twofold-coordinated Sn centers. Assessment of luminescence spectra and decay dynamics suggest the energy transfer mechanism to be essentially of the resonant radiative type. Moreover, a connection between the luminescent and structural properties of the rare-earth doped glass system was demonstrated. Raman spectroscopy characterization revealed that no significant variation in the glass matrix is induced by Sm 3+ doping at the concentration employed. A comparison was made with a structural study performed on the Eu 3+ doped system (containing 2 mol% Eu 2O 3 along with 4 mol% of each Ag 2O and SnO) where the radiative energy transfer mechanism was previously established. The data appears consistent regarding the lack of variation in glass structure upon the Eu 3+ and Sm 3+ doping in connection with the dominance of the radiative transfer in the matrix. Thermal treatment of the material leads to precipitation of Ag nanoparticles of a broad size range inside the dielectric as observed by transmission electron microspcopy. Assessment of 4G 5/2 excited state decay in Sm 3+ ions shows no influence from the silver particles.

  5. Samarium (III) adsorption on bentonite modified with N-(2-hydroxyethyl) ethylenediamine.

    Science.gov (United States)

    Li, Dandan; Chang, Xijun; Hu, Zheng; Wang, Qihui; Li, Ruijun; Chai, Xiaoli

    2011-02-15

    A new material has been synthesized using dry process to activate bentonite followed by N-(2-hydroxyethyl) ethylenediamine connecting chlorosilane coupling agent. The synthesized new material was characterized by elemental analysis, FT-IR and thermogravimetry which proved that bentonite was successfully modified. The most interesting trait of the new material was its selective adsorption for rare earth elements. A variety of conditions of the new material were investigated for adsorption. The optimal conditions were determined with respect to pH and shaking time. Samarium (Sm) was quantitatively adsorbed at pH 4 and shaking time of 2 min onto the new material. Under these conditions the maximum static adsorption capacity of Sm(III) was found to be 17.7 mg g(-1). The adsorbed Sm(III) ion were quantitatively eluted by 2.0 mL 0.1 mol L(-1) HCl and 5% CS (NH(2))(2) solution. According to IUPAC definition, the detection limit (3σ) of this method was 0.60 ng mL(-1). The relative standard deviation (RSD) under optimum conditions was less than 3% (n=8). The new material also was applied for the preconcentration of trace Sm(III) in environmental samples with satisfactory results. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Understanding and Improving High-Temperature Structural Properties of Metal-Silicide Intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Bruce S. Kang

    2005-10-10

    The objective of this project was to understand and improve high-temperature structural properties of metal-silicide intermetallic alloys. Through research collaboration between the research team at West Virginia University (WVU) and Dr. J.H. Schneibel at Oak Ridge National Laboratory (ORNL), molybdenum silicide alloys were developed at ORNL and evaluated at WVU through atomistic modeling analyses, thermo-mechanical tests, and metallurgical studies. In this study, molybdenum-based alloys were ductilized by dispersing MgAl2O4 or MgO spinel particles. The addition of spinel particles is hypothesized to getter impurities such as oxygen and nitrogen from the alloy matrix with the result of ductility improvement. The introduction of fine dispersions has also been postulated to improve ductility by acting as a dislocation source or reducing dislocation pile-ups at grain boundaries. The spinel particles, on the other hand, can also act as local notches or crack initiation sites, which is detrimental to the alloy mechanical properties. Optimization of material processing condition is important to develop the desirable molybdenum alloys with sufficient room-temperature ductility. Atomistic analyses were conducted to further understand the mechanism of ductility improvement of the molybdenum alloys and the results showed that trace amount of residual oxygen may be responsible for the brittle behavior of the as-cast Mo alloys. For the alloys studied, uniaxial tensile tests were conducted at different loading rates, and at room and elevated temperatures. Thermal cycling effect on the mechanical properties was also studied. Tensile tests for specimens subjected to either ten or twenty thermal cycles were conducted. For each test, a follow-up detailed fractography and microstructural analysis were carried out. The test results were correlated to the size, density, distribution of the spinel particles and processing time. Thermal expansion tests were carried out using thermo

  7. Chemical vapour deposition of tungsten and tungsten silicide layers for applications in novel silicon technology

    CERN Document Server

    Li, F X

    2002-01-01

    This work was a detailed investigation into the Chemical Vapour Deposition (CVD) of tungsten and tungsten silicide for potential applications in integrated circuit (IC) and other microelectronic devices. These materials may find novel applications in contact schemes for transistors in advanced ICs, buried high conductivity layers in novel Silicon-On-Insulator (SOI) technology and in power electronic devices. The CVD techniques developed may also be used for metal coating of recessed or enclosed features which may occur in novel electronic or electromechanical devices. CVD of tungsten was investigated using the silicon reduction reaction of WF sub 6. W layers with an optimum self-limiting thickness of 100 nm and resistivity 20 mu OMEGA centre dot cm were produced self-aligned to silicon. A hydrogen passivation technique was developed as part of the wafer pre-clean schedule and proved essential in achieving optimum layer thickness. Layers produced by this approach are ideal for intimate contact to shallow junct...

  8. Hydrogen generation systems utilizing sodium silicide and sodium silica gel materials

    Science.gov (United States)

    Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

    2015-07-14

    Systems, devices, and methods combine reactant materials and aqueous solutions to generate hydrogen. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Multiple inlets of varied placement geometries deliver aqueous solution to the reaction. The reactant materials and aqueous solution are churned to control the state of the reaction. The aqueous solution can be recycled and returned to the reaction. One system operates over a range of temperatures and pressures and includes a hydrogen separator, a heat removal mechanism, and state of reaction control devices. The systems, devices, and methods of generating hydrogen provide thermally stable solids, near-instant reaction with the aqueous solutions, and a non-toxic liquid by-product.

  9. Hydrogen generation systems and methods utilizing sodium silicide and sodium silica gel materials

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

    2017-12-19

    Systems, devices, and methods combine thermally stable reactant materials and aqueous solutions to generate hydrogen and a non-toxic liquid by-product. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Springs and other pressurization mechanisms pressurize and deliver an aqueous solution to the reaction. A check valve and other pressure regulation mechanisms regulate the pressure of the aqueous solution delivered to the reactant fuel material in the reactor based upon characteristics of the pressurization mechanisms and can regulate the pressure of the delivered aqueous solution as a steady decay associated with the pressurization force. The pressure regulation mechanism can also prevent hydrogen gas from deflecting the pressure regulation mechanism.

  10. Friction and wear of radiofrequency-sputtered borides, silicides, and carbides

    Science.gov (United States)

    Brainard, W. A.; Wheeler, D. R.

    1978-01-01

    The friction and wear properties of several refractory compound coatings were examined. These compounds were applied to 440 C bearing steel surfaces by radiofrequency (RF) sputtering. The refractory compounds were the titanium and molybdenum borides, the titanium and molybdenum silicides, and the titanium, molybdenum, and boron carbides. Friction testing was done with a pin-on-disk wear apparatus at loads from 0.1 to 5.0 newtons. Generally, the best wear properties were obtained when the coatings were bias sputtered onto 440 C disks that had been preoxidized. Adherence was improved because of the better bonding of the coatings to the iron oxide formed during preoxidation. As a class the carbides provided wear protection to the highest loads. Titanium boride coatings provided low friction and good wear properties to moderate loads.

  11. Hydrogen generation systems and methods utilizing sodium silicide and sodium silica gel materials

    Science.gov (United States)

    Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

    2015-08-11

    Systems, devices, and methods combine thermally stable reactant materials and aqueous solutions to generate hydrogen and a non-toxic liquid by-product. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Springs and other pressurization mechanisms pressurize and deliver an aqueous solution to the reaction. A check valve and other pressure regulation mechanisms regulate the pressure of the aqueous solution delivered to the reactant fuel material in the reactor based upon characteristics of the pressurization mechanisms and can regulate the pressure of the delivered aqueous solution as a steady decay associated with the pressurization force. The pressure regulation mechanism can also prevent hydrogen gas from deflecting the pressure regulation mechanism.

  12. Hydrogen generation systems utilizing sodium silicide and sodium silica gel materials

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

    2017-06-06

    Systems, devices, and methods combine reactant materials and aqueous solutions to generate hydrogen. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Multiple inlets of varied placement geometries deliver aqueous solution to the reaction. The reactant materials and aqueous solution are churned to control the state of the reaction. The aqueous solution can be recycled and returned to the reaction. One system operates over a range of temperatures and pressures and includes a hydrogen separator, a heat removal mechanism, and state of reaction control devices. The systems, devices, and methods of generating hydrogen provide thermally stable solids, near-instant reaction with the aqueous solutions, and a non-toxic liquid by-product.

  13. Discovery of Brownleeite: a New Manganese Silicide Mineral in an Interplanetary Dust Particle

    Science.gov (United States)

    Keller, Lindsay P.; Nakamura-Messenger, Keiko; Clemett, Simon J.; Messenger, Scott; Jones, John H.; Palma, Russell L.; Pepin, Robert O.; Klock, Wolfgang; Zolensky, Michael E.; Tatsuoka, Hirokazu

    2011-01-01

    The Earth accretes approximately 40,000 tons of cosmic dust annually, originating mainly from the disintegration of comets and collisions among asteroids. This cosmic dust, also known as interplanetary dust particles (IDPs), is a subject of intense interest since it is made of the original building blocks of our Solar System. Although the specific parent bodies of IDPs are unknown, the anhydrous chondritic-porous IDPs (CP-IDPs) subset has been potentially linked to a cometary source. The CP-IDPs are extremely primitive materials based on their unequilibrated mineralogy, C-rich chemistry, and anomalous isotopic signatures. In particular, some CP-IDPs escaped the thermal, aqueous and impact shock processing that has modified or destroyed the original mineralogy of meteorites. Thus, the CP-IDPs represent some of the most primitive solar system materials available for laboratory study. Most CP-IDPs are comprised of minerals that are common on Earth. However, in the course of an examination of one of the CP-IDPs, we encountered three sub-micrometer sized grains of manganese silicide (MnSi), a phase that has heretofore not been found in nature. In the seminar, we would like to focus on IDP studies and this manganese silicide phase that has been approved as the first new mineral identified from a comet by the International Mineralogical Association (IMA) in 2008. The mineral is named in honour of Donald E. Brownlee, an American astronomer and a founder of the field of cosmic dust research who is the principal investigator of the NASA Stardust Mission that collected dust samples from Comet 81P/Wild-2 and returned them to Earth. Much of our current view and understanding of the early solar system would not exist without the pioneering work of professor Don Brownlee in the study of IDPs.

  14. Characterisation of amorphous molybdenum silicide (MoSi) superconducting thin films and nanowires

    Science.gov (United States)

    Banerjee, Archan; Baker, Luke J.; Doye, Alastair; Nord, Magnus; Heath, Robert M.; Erotokritou, Kleanthis; Bosworth, David; Barber, Zoe H.; MacLaren, Ian; Hadfield, Robert H.

    2017-08-01

    We report on the optimisation of amorphous molybdenum silicide thin film growth for superconducting nanowire single-photon detector (SNSPD) applications. Molybdenum silicide was deposited via co-sputtering from Mo and Si targets in an Ar atmosphere. The superconducting transition temperature (T c) and sheet resistance (R s) were measured as a function of thickness and compared to several theoretical models for disordered superconducting films. Superconducting and optical properties of amorphous materials are very sensitive to short- (up to 1 nm) and medium-range order (˜1-3 nm) in the atomic structure. Fluctuation electron microscopy studies showed that the films assumed an A15-like medium-range order. Electron energy loss spectroscopy indicates that the film stoichiometry was close to Mo83Si17, which is consistent with reports that many other A15 structures with the nominal formula A 3 B show a significant non-stoichiometry with A:B > 3:1. Optical properties from ultraviolet (270 nm) to infrared (2200 nm) wavelengths were measured via spectroscopic ellipsometry for 5 nm thick MoSi films indicating high long wavelength absorption. We also measured the current density as a function of temperature for nanowires patterned from a 10 nm thick MoSi film. The current density at 3.6 K is 3.6 × 105 A cm-2 for the widest wire studied (2003 nm), falling to 2 × 105 A cm-2 for the narrowest (173 nm). This investigation confirms the excellent suitability of MoSi for SNSPD applications and gives fresh insight into the properties of the underlying materials.

  15. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mandiwana, Vusani, E-mail: VMandiwana@csir.co.za; Kalombo, Lonji, E-mail: LKalombo@csir.co.za [Centre of Polymers and Composites, CSIR (South Africa); Venter, Kobus, E-mail: Kobus.Venter@mrc.ac.za [South African Medical Research Council (South Africa); Sathekge, Mike, E-mail: Mike.Sathekge@up.ac.za [University of Pretoria and Steve Biko Academic Hospital, Department of Nuclear Medicine (South Africa); Grobler, Anne, E-mail: Anne.Grobler@nwu.ac.za; Zeevaart, Jan Rijn, E-mail: zeevaart@necsa.co.za [North-West University, DST/NWU Preclinical Drug Development Platform (South Africa)

    2015-09-15

    Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([{sup 153}Sm]Sm{sub 2}O{sub 3}) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive {sup 153}Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The {sup 153}Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [{sup 153}Sm]Sm{sub 2}O{sub 3} loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [{sup 153}Sm]Sm{sub 2}O{sub 3}-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

  16. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    Science.gov (United States)

    Mandiwana, Vusani; Kalombo, Lonji; Venter, Kobus; Sathekge, Mike; Grobler, Anne; Zeevaart, Jan Rijn

    2015-09-01

    Developing nanoparticulate delivery systems that will allow easy movement and localization of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge in nanomedicine. The aim of this study was to evaluate the biodistribution of poly( d, l-lactide- co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([153Sm]Sm2O3) in vivo to prove that orally administered nanoparticles alter the biodistribution of a drug. These were then activated in a nuclear reactor to produce radioactive 153Sm-loaded-PLGA nanoparticles. The nanoparticles were characterized for size, zeta potential, and morphology. The nanoparticles were orally and intravenously (IV) administered to rats in order to trace their uptake through imaging and biodistribution studies. The 153Sm-loaded-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The zeta potential ranged between 5 and 20 mV. The [153Sm]Sm2O3 loaded PLGA nanoparticles, orally administered were distributed to most organs at low levels, indicating that there was absorption of nanoparticles. While the IV injected [153Sm]Sm2O3-loaded PLGA nanoparticles exhibited the highest localization of nanoparticles in the spleen (8.63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems would be suitable for improving permeability and thus the bioavailability of therapeutic compounds.

  17. Fabrication and properties of samarium doped calcium sulphate thin films using spray pyrolysis technique

    Energy Technology Data Exchange (ETDEWEB)

    Reghima, Meriem [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia); Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Faculté des Sciences de Bizerte, Université de Carthage, Zarzouna 7021 (Tunisia); Guasch, Cathy [Institut d' Electronique et des systèmes, Unité Mixte de Recherche 5214 UM2-CNRS (ST2i) – Université Montpellier, 860 rue de Saint Priest, Bâtiment 5, 34097 Montpellier (France); Azzaza, Sonia; Alleg, Safia [Laboratoire de Magnétisme et Spectroscopie des Solides (LM2S), Département de Physique, Faculté des Sciences, Université Badji Mokhtar Annaba, B.P. 12, 23000 Annaba (Algeria); Kamoun-Turki, Najoua [Université Tunis El Manar, Faculté des Sciences de Tunis, Département de Physique, LR99ES13 Laboratoire de Physique de la Matière Condensée (LPMC), 2092 Tunis, Tunisie (Tunisia)

    2016-10-01

    Using low cost spray pyrolysis technique, polycrystalline CaSO{sub 4} thin films were successfully grown on a glass substrate with a thickness of about 1 μm. Samarium doping has been performed on CaSO{sub 4} thin films to explore luminescence properties. The characterizations of these films were carried out using X-ray diffraction, Scanning Electron Microscopy and optical measurements. The structural analyses reveal the existence of hexagonal CaSO{sub 4} phase with a (200) preferred orientation belonging to CaS compound for substrate temperatures below 350 °C. It is shown that the crystallinity of the sprayed thin films can be improved by increasing substrate temperature up to 250 °C. Warren-Averbach analysis has been applied on X-ray diffractogram to determine structural parameters involving the phase with its amount, the grain size and the lattice parameters using Maud software. The surface topography shows a rough surface covered by densely packed agglomerated clusters having faceted and hexagonal shapes. Energy dispersive microscopy measurements confirm the presence of calcium and sulfur in equal proportions as well as high percentage of oxygen. Photoluminescence at room temperature revealed that luminescence peaks are attributed to the intrinsic emission of pure CaSO{sub 4} phase. - Highlights: • Warren Averbach analysis reveal the presence of hcp structure of CaSO{sub 4} phase. • A mixture of CaSO{sub 4} and CaHO{sub 4.5}S phases has been detected for lower T{sub s}. • For increasing T{sub s}, the CaHO{sub 4.5}S phase has been disappeared. • The origin of PL peaks has been identified.

  18. Copper silicide/silicon nanowire heterostructures: in situ TEM observation of growth behaviors and electron transport properties.

    Science.gov (United States)

    Chiu, Chung-Hua; Huang, Chun-Wei; Chen, Jui-Yuan; Huang, Yu-Ting; Hu, Jung-Chih; Chen, Lien-Tai; Hsin, Cheng-Lun; Wu, Wen-Wei

    2013-06-07

    Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu3Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu3Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu3Si/Si heterostructure interfaces and metallic Cu3Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu3Si/Si, but also suggested the potential application of Cu3Si at nanoscale for future processing in nanotechnology.

  19. Electronic structures of platinum group elements silicides calculated by a first-principle pseudopotential method using plane-wave basis

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Y. [National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, Higashi 1-1 Tsukuba, Ibaraki 305-8565 (Japan); Watanabe, A. [National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, Higashi 1-1 Tsukuba, Ibaraki 305-8565 (Japan)

    2006-06-29

    The electronic structures of platinum group elements (Ru, Os, Rh, Ir, Pd, and Pt) silicides have been calculated. Ir{sub 3}Si{sub 5} is a semiconductor with the direct gap of 1.14 eV. Among monosilicides, RuSi and OsSi with the FeSi-type structure are semiconductors with the gap values of 0.21 and 0.41 eV but RhSi, IrSi, PdSi, and PtSi with the MnP-type structure are metals. No semiconducting compounds can be found in other platinum group elements silicides other than known Ru{sub 2}Si{sub 3}, Os{sub 2}Si{sub 3}, and OsSi{sub 2}.

  20. High Temperature Silicides and Refractory Alloys Symposium Held in Boston, Massachusetts on November 29 -December 2, 1993. Volume 322

    Science.gov (United States)

    1993-12-02

    MECHANICAL BEHAVIOR OF Nb-Ti BASE BETA + SILICIDE ALLOYS . ................................... 491 P.R. Subramanian, M.G. Mendiratta, and D.M. Dimiduk...above -1300°C, the amorphous silica can transform to a- cristobalite . The oxygen diffusivity will change as the structure of the silica changes, and...first 10 to 40 hours. After 100 hours of oxidation, the XRD analysis shows that the oxide layer is cristobalite , the stable crystalline phase of silica

  1. Aluminium alloyed iron-silicide/silicon solar cells: A simple approach for low cost environmental-friendly photovoltaic technology

    Science.gov (United States)

    Kumar Dalapati, Goutam; Masudy-Panah, Saeid; Kumar, Avishek; Cheh Tan, Cheng; Ru Tan, Hui; Chi, Dongzhi

    2015-01-01

    This work demonstrates the fabrication of silicide/silicon based solar cell towards the development of low cost and environmental friendly photovoltaic technology. A heterostructure solar cells using metallic alpha phase (α-phase) aluminum alloyed iron silicide (FeSi(Al)) on n-type silicon is fabricated with an efficiency of 0.8%. The fabricated device has an open circuit voltage and fill-factor of 240 mV and 60%, respectively. Performance of the device was improved by about 7 fold to 5.1% through the interface engineering. The α-phase FeSi(Al)/silicon solar cell devices have promising photovoltaic characteristic with an open circuit voltage, short-circuit current and a fill factor (FF) of 425 mV, 18.5 mA/cm2, and 64%, respectively. The significant improvement of α-phase FeSi(Al)/n-Si solar cells is due to the formation p+−n homojunction through the formation of re-grown crystalline silicon layer (~5–10 nm) at the silicide/silicon interface. Thickness of the regrown silicon layer is crucial for the silicide/silicon based photovoltaic devices. Performance of the α-FeSi(Al)/n-Si solar cells significantly depends on the thickness of α-FeSi(Al) layer and process temperature during the device fabrication. This study will open up new opportunities for the Si based photovoltaic technology using a simple, sustainable, and los cost method. PMID:26632759

  2. Evaluation of powder metallurgical processing routes for multi-component niobium silicide-based high-temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Seemueller, Hans Christoph Maximilian

    2016-03-22

    Niobium silicide-based composites are potential candidates to replace nickel-base superalloys for turbine applications. The goal of this work was to evaluate the feasibility and differences in ensuing properties of various powder metallurgical processing techniques that are capable of manufacturing net-shape turbine components. Two routes for powder production, mechanical alloying and gas atomization were combined with compaction via hot isostatic pressing and powder injection molding.

  3. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P

    2017-01-01

    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 keV. This...

  4. Electrical and optical properties of sub-10 nm nickel silicide films for silicon solar cells

    Science.gov (United States)

    Brahmi, Hatem; Ravipati, Srikanth; Yarali, Milad; Shervin, Shahab; Wang, Weijie; Ryou, Jae-Hyun; Mavrokefalos, Anastassios

    2017-01-01

    Highly conductive and transparent films of ultra-thin p-type nickel silicide films have been prepared by RF magnetron sputtering of nickel on silicon substrates followed by rapid thermal annealing in an inert environment in the temperature range 400-600 °C. The films are uniform throughout the wafer with thicknesses in the range of 3-6 nm. The electrical and optical properties are presented for nickel silicide films with varying thickness. The Drude-Lorentz model and Fresnel equations were used to calculate the dielectric properties, sheet resistance, absorption and transmission of the films. These ultrathin nickel silicide films have excellent optoelectronic properties for p-type contacts with optical transparencies up to 80% and sheet resistance as low as ~0.15 µΩ cm. Furthermore, it was shown that the use of a simple anti-reflection (AR) coating can recover most of the reflected light approaching the values of a standard Si solar cell with the same AR coating. Overall, the combination of ultra-low thickness, high transmittance, low sheet resistance and ability to recover the reflected light by utilizing standard AR coating makes them ideal for utilization in silicon based photovoltaic technologies as a p-type transparent conductor.

  5. Pack cementation Cr-Al coating of steels and Ge-doped silicide coating of Cr-Nb alloy

    Energy Technology Data Exchange (ETDEWEB)

    He, Y.R.; Zheng, M.H.; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)

    1995-08-01

    Carbon steels or low-alloy steels used in utility boilers, heat exchangers, petrochemical plants and coal gasification systems are subjected to high temperature corrosion attack such as oxidation, sulfidation and hot corrosion. The pack cementation coating process has proven to be an economical and effective method to enhance the corrosion resistance by modifying the surface composition of steels. With the aid of a computer program, STEPSOL, pack cementation conditions to produce a ferrite Cr-Al diffusion coating on carbon-containing steels by using elemental Cr and Al powders have been calculated and experimentally verified. The cyclic oxidation kinetics for the Cr-Al coated steels are presented. Chromium silicide can maintain high oxidation resistance up to 1100{degrees}C by forming a SiO{sub 2} protective scale. Previous studies at Ohio State University have shown that the cyclic oxidation resistance of MOSi{sub 2} and TiSi{sub 2} can be further improved by Ge addition introduced during coating growth. The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating in a single processing step for the ORNL-developed Cr-Nb advanced intermetallic alloy. The oxidation behavior of the silicide-coated Cr-Nb alloy was excellent: weight gain of about 1 mg/cm{sup 2} upon oxidation at 1100{degrees}C in air for 100 hours.

  6. Optical response and magnetic characteristic of samarium doped zinc phosphate glasses containing nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Azmi, Siti Amlah M.; Sahar, M.R., E-mail: mrahim057@gmail.com

    2015-11-01

    A magnetic glass of composition 40ZnO–(58−x) P{sub 2}O{sub 5}–1Sm{sub 2}O{sub 3}–xNiO, with x=0.0, 1.0, 1.5 and 2.0 mol% is prepared by melt-quenching technique. The glass is characterized by X-ray diffraction, high-resolution transmission electron microscope (HRTEM), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM) analysis. The X-rays diffraction confirms the amorphous nature of the glass while the HRTEM analysis reveals the presence of nickel nanoparticles in the glass samples. High-resolution TEM reveals that the lattice spacing of nickel nanoparticles is 0.35 nm at (100) plane. Photoluminescence emission shows the existence of four peaks that correspond to the transition from the upper level of {sup 4}G{sub 5/2} to the lower level of {sup 6}H{sub 5/2}, {sup 6}H{sub 7/2}, {sup 6}H{sub 9/2,} and {sup 6}H{sub 11/2.} It is observed that all peaks experience significant quenching effect with the increasing concentration of nickel nanoparticles, suggesting a strong energy transfer from excited samarium ions to the nickel ions. The glass magnetization and susceptibility at 12 kOe at room temperature are found to be in the range of (3.87±0.17×10{sup −2}–7.19±0.39×10{sup −2}) emu/g and (3.24±0.16×10{sup −6}–5.99±0.29×10{sup −6}) emu/Oe g respectively. The obtained hysteresis curve indicates that the glass samples are paramagnetic materials. The studied glass can be further used towards the development of magneto-optical functional glass. - Highlights: • Sm{sup 3+} doped zinc phosphate glass embedded with Ni NPs has been prepared. • The Laue pattern and lattice spacing of Ni NPs are confirmed by HRTEM image. • The magnetic response of glasses has been studied through VSM analysis. • Enhancement factor and decay half-lifetime are investigated.

  7. Treatment of bone pain secondary to metastases using samarium-153-EDTMP

    Directory of Open Access Journals (Sweden)

    Elba Cristina Sá de Camargo Etchebehere

    Full Text Available CONTEXT: More than 50% of patients with prostate, breast or lung cancer will develop painful bone metastases. The purpose of treating bone metastases is to relieve pain, reduce the use of steroids and to maintain motion. OBJECTIVE: To evaluate the use of samarium-153-EDTMP (153Sm-EDTMP for the treatment of bone pain secondary to metastases that is refractory to clinical management. TYPE OF STUDY: Retrospective. SETTING: Division of Nuclear Medicine, Universidade Estadual de Campinas (Unicamp. METHODS: Fifty-eight patients were studied (34 males with mean age 62 years; 31 patients had prostate cancer, 20 had breast cancer, three had lung cancer, one had lung hemangioendothelioma, one had parathyroid adenocarcinoma, one had osteosarcoma and one had an unknown primary tumor. All patients had multiple bone metastases demonstrated by bone scintigraphy using 99mTc-MDP,and were treated with 153Sm-EDTMP. Response to treatment was graded as good (pain reduction of 50-100%, intermediate (25-49% and poor (0-24%. RESULTS: All patients showed good uptake of 153Sm-EDTMP by bone metastases. Among the patients with prostate cancer, intermediate or good response to therapy occurred in 80.6% (25 patients and poor response in 19.4% (6. Among the patients with breast cancer, 85% (17 showed intermediate or good response to therapy while 15% (3 showed poor response. All three patients with lung cancer showed poor response to treatment. The lung hemangioendothelioma and unknown primary lesion patients showed intermediate response to treatment; the osteosarcoma and parathyroid adenocarcinoma patients showed good response to treatment. No significant myelotoxicity occurred. DISCUSSION: Pain control is important for improving the quality of life of patients with advanced cancers. The mechanism by which pain is relieved with the use of radionuclides is still not yet completely understood, however, the treatment is simple and provides a low risk of mielotoxicity

  8. Anchoring samarium oxide nanoparticles on reduced graphene oxide for high-performance supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Dezfuli, Amin Shiralizadeh [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Ganjali, Mohammad Reza, E-mail: ganjali@khayam.ut.ac.ir [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Biosensor Research Center, Endocrinology & Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Naderi, Hamid Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

    2017-04-30

    Highlights: • Samarium oxide nanoparticles have been anchored on the surface of reduced graphene oxide for the first time. • Sm{sub 2}O{sub 3}/RGO nanocomposite show high capacitance, good rate and cycling performance. • Sm{sub 2}O{sub 3}/RGO nanocomposite can serve as efficient electrode material for energy storage. • The best composite electrode exhibits specific capacitance of 321 F g{sup −1} in 2 mV s{sup −1}. - Abstract: We have synthesized Sm{sub 2}O{sub 3} nanoparticles (SmNs) and anchored them onto the surface of reduced graphene oxide (RGO) through a self-assembly thereof by utilizing a facile sonochemical procedure. The nanomaterials were characterized by means of powder X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR) spectra, and X-ray photoelectron spectroscopy (XPS). As the next step, the supercapacitive behavior of the resulting nanocomposites were investigated when used as electrode material, through with cyclic voltammetric (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The SmNs decorated RGO (SmN-RGO) nanocomposites were found to possess a specific capacitance (SC) of 321 F g{sup −1} when used in a 0.5 M Na{sub 2}SO{sub 4} solution as an electrolyte, in a scan rate of 2 mV s{sup −1}. The SC of the SmN-RGO based electrodes were also found to be 268 F g{sup −1} at a current density of 2 A g{sup −1} through galvanostatic charge-discharge tests. The outstanding properties of the SmN-RGOs were attributed to synergy of the high charge mobility of SmNs and the flexibility of the sheets of RGOs. Additionally, the nano-composite revealed a unique cycling durability (maintaining 99% of its SC even after 4000 cycles).

  9. Rate Theory Modeling and Simulations of Silicide Fuel at LWR Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinbin [Argonne National Lab. (ANL), Argonne, IL (United States); Ye, Bei [Argonne National Lab. (ANL), Argonne, IL (United States); Mei, Zhigang [Argonne National Lab. (ANL), Argonne, IL (United States); Hofman, Gerard [Argonne National Lab. (ANL), Argonne, IL (United States); Yacout, Abdellatif [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-12-10

    Uranium silicide (U3Si2) fuel has higher thermal conductivity and higher uranium density, making it a promising candidate for the accident-tolerant fuel (ATF) used in light water reactors (LWRs). However, previous studies on the fuel performance of U3Si2, including both experimental and computational approaches, have been focusing on the irradiation conditions in research reactors, which usually involve low operation temperatures and high fuel burnups. Thus, it is important to examine the fuel performance of U3Si2 at typical LWR conditions so as to evaluate the feasibility of replacing conventional uranium dioxide fuel with this silicide fuel material. As in-reactor irradiation experiments involve significant time and financial cost, it is appropriate to utilize modeling tools to estimate the behavior of U3Si2 in LWRs based on all those available research reactor experimental references and state-of-the-art density functional theory (DFT) calculation capabilities at the early development stage. Hence, in this report, a comprehensive investigation of the fission gas swelling behavior of U3Si2 at LWR conditions is introduced. The modeling efforts mentioned in this report was based on the rate theory (RT) model of fission gas bubble evolution that has been successfully applied for a variety of fuel materials at devious reactor conditions. Both existing experimental data and DFT-calculated results were used for the optimization of the parameters adopted by the RT model. Meanwhile, the fuel-cladding interaction was captured by the coupling of the RT model with simplified mechanical correlations. Therefore, the swelling behavior of U3Si2 fuel and its consequent interaction with cladding in LWRs was predicted by the rate theory modeling, providing valuable information for the development of U3Si2 fuel as an accident

  10. Large-format platinum silicide microwave kinetic inductance detectors for optical to near-IR astronomy.

    Science.gov (United States)

    Szypryt, P; Meeker, S R; Coiffard, G; Fruitwala, N; Bumble, B; Ulbricht, G; Walter, A B; Daal, M; Bockstiegel, C; Collura, G; Zobrist, N; Lipartito, I; Mazin, B A

    2017-10-16

    We have fabricated and characterized 10,000 and 20,440 pixel Microwave Kinetic Inductance Detector (MKID) arrays for the Dark-speckle Near-IR Energy-resolved Superconducting Spectrophotometer (DARKNESS) and the MKID Exoplanet Camera (MEC). These instruments are designed to sit behind adaptive optics systems with the goal of directly imaging exoplanets in a 800-1400 nm band. Previous large optical and near-IR MKID arrays were fabricated using substoichiometric titanium nitride (TiN) on a silicon substrate. These arrays, however, suffered from severe non-uniformities in the TiN critical temperature, causing resonances to shift away from their designed values and lowering usable detector yield. We have begun fabricating DARKNESS and MEC arrays using platinum silicide (PtSi) on sapphire instead of TiN. Not only do these arrays have much higher uniformity than the TiN arrays, resulting in higher pixel yields, they have demonstrated better spectral resolution than TiN MKIDs of similar design. PtSi MKIDs also do not display the hot pixel effects seen when illuminating TiN on silicon MKIDs with photons with wavelengths shorter than 1 µm.

  11. Formation of the Thermoelectric Candidate Chromium Silicide by Use of a Pack-Cementation Process

    Science.gov (United States)

    Stathokostopoulos, D.; Chaliampalias, D.; Tarani, E.; Theodorakakos, A.; Giannoulatou, V.; Polymeris, G. S.; Pavlidou, E.; Chrissafis, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Vourlias, G.

    2014-10-01

    Transition-metal silicides are reported to be good candidates for thermoelectric applications because of their thermal and structural stability, high electrical conductivity, and generation of thermoelectric power at elevated temperatures. Chromium disilicide (CrSi2) is a narrow-gap semiconductor and a potential p-type thermoelectric material up to 973 K with a band gap of 0.30 eV. In this work, CrSi2 was formed from Si wafers by use of a two-step, pack-cementation, chemical diffusion method. Several deposition conditions were used to investigate the effect of temperature and donor concentration on the structure of the final products. Scanning electron microscopy and x-ray diffraction analysis were performed for phase identification, and thermal stability was evaluated by means of thermogravimetric measurements. The results showed that after the first step, chromizing, the structure of the products was a mixture of several Cr-Si phases, depending on the donor (Cr) concentration during the deposition process. After the second step, siliconizing, the pure CrSi2 phase was formed as a result of Si enrichment of the initial Cr-Si phases. It was also revealed that this compound has thermoelectric properties similar to those reported elsewhere. Moreover, it was found to have exceptional chemical stability even at temperatures up to 1273 K.

  12. XTEM Studies of Nickel Silicide Growth on Si(100) Using a Ni/Ti Bilayer System

    Science.gov (United States)

    Falke, U.; Fenske, F.; Schulze, S.; Hietschold, M.

    1997-08-01

    Using a Ni/Ti bilayer system on Si(100) substrates we found a preferential growth of epitaxial NiSi2 at reaction temperatures of about 475 °C. This is attributed to the relatively slow Ni transport rate through the Ti layer, which acts as a diffusion rate limiting barrier. Annealing temperatures of 500 °C lead to the formation of mainly orthorhombic NiSi with a small fraction of NiSi2. The silicide phases grow with well defined orientations with respect to the underlying Si lattice for annealing temperatures up to 475 °C. An einem Ni/Ti-Zweischichtsystem auf Si(100)-Substraten fanden wir ein bevorzugtes Wachstum von epitaktischem NiSi2 bei Reaktionstemperaturen von 475 °C. Das wird auf die geringe Transportrate für Ni durch die Ti-Schicht, die als Barriere zur Begrenzung der Diffusionsrate dient, zurückgeführt. Temperaturen von 500 °C führen zur Bildung von hauptsächlich orthorhombischem NiSi und, in geringem Maß, von NiSi2. Bis zu Temperaturen von 475 °C wachsen die Silicidphasen mit definierten Orientierungen in Bezug auf das darunterliegende Si-Gitter.

  13. Mesoscale Evaluation of Titanium Silicide Monolayer as a Cathode Host Material in Lithium-Sulfur Batteries

    Science.gov (United States)

    Liu, Zhixiao; Balbuena, Perla B.; Mukherjee, Partha P.

    2017-09-01

    Two-dimensional materials are competitive candidates as cathode materials in lithium-sulfur batteries for immobilizing soluble polysulfides and mitigating the shuttle effect. In this study, a mesoscale modeling approach, which combines first-principles simulation and kinetic Monte Carlo simulation, is employed to evaluate titanium silicide (Ti2Si and TiSi2) monolayers as potential host materials in lithium-sulfur batteries. It is found that the Ti2Si monolayer has much stronger affinities to Li2S x ( x = 1, 2, 4) molecules than does the TiSi2 monolayer. Also, Ti2Si can facilitate the dissociation of long-chain Li2S4 to LiS2. On the other hand, TiSi2 can only provide a weak chemical interaction for trapping soluble Li2S4. Therefore, the Ti2Si monolayer can be considered to be the next-generation cathode material for lithium-sulfur batteries. Nevertheless, the strong interaction between Ti2Si and Li2S also causes fast surface passivation. How to control the Li2S precipitation on Ti2Si should be answered by future studies.

  14. Crystal structure of the ternary silicide Gd2Re3Si5

    Directory of Open Access Journals (Sweden)

    Vitaliia Fedyna

    2014-12-01

    Full Text Available A single crystal of the title compound, the ternary silicide digadolinium trirhenium pentasilicide, Gd2Re3Si5, was isolated from an alloy of nominal composition Gd20Re30Si50 synthesized by arc melting and investigated by X-ray single-crystal diffraction. Its crystal structure belongs to the U2Mn3Si5 structure type. All atoms in the asymmetric lie on special positions. The Gd site has site symmetry m..; the two Mn atoms have site symmetries m.. and 2.22; the three Si atoms have site symmetries m.., ..2 and 4.. . The coordination polyhedra of the Gd atoms have 21 vertices, while those of the Re atoms are cubooctahedra and 13-vertex polyhedra. The Si atoms are arranged as tricapped trigonal prisms, bicapped square antiprisms, or 11-vertex polyhedra. The crystal structure of the title compound is also related to the structure types CaBe2Ge2 and W5Si3. It can be represented as a stacking of Gd-centred polyhedra of composition [GdSi9]. The Re atoms form infinite chains with an Re—Re distance of 2.78163 (5 Å and isolated squares with an Re—Re distance of 2.9683 (6 Å.

  15. The new ternary silicide ErCo{sub 3}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Dzevenko, Mariya; Bigun, Inna [Ivan Franko National Univ., Lviv (Ukraine). Dept. of Analytical Chemistry

    2014-03-15

    The new ternary silicide ErCo{sub 3}Si{sub 2} adopts the ErRh{sub 3}Si{sub 2} structure type (space group Imma, Pearson code oI24, Z = 4, a = 6.950(1), b = 9.020(2), c = 5.230(1) A, R{sub 1} = 0.0565, wR{sub 2} = 0.0355, 253 F{sup 2} values, 23 variables). It is a deformation derivative of the CeCo{sub 3}B{sub 2} structure type. The coordination of the Er atom shows a normal 20-vertex polyhedron [Er(Si{sub 6}Co{sub 12}Er{sub 2})]. The two similar coordination polyhedra of Co are a distorted icosahedron [Co(Si{sub 4}Co{sub 4}Er{sub 4})], and a distorted icosahedron with one capped face [Co(Si{sub 4}Co{sub 5}Er{sub 4})]. The Si atom is surrounded by the polyhedron [Si(Co{sub 6}Si{sub 2}Er{sub 3})]. (orig.)

  16. Status of core conversion with LEU silicide fuel in JRR-4

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Teruo; Ohnishi, Nobuaki; Shirai, Eiji [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

    1997-08-01

    Japan Research Reactor No.4 (JRR-4) is a light water moderated and cooled, 93% enriched uranium ETR-type fuel used and swimming pool type reactor with thermal output of 3.5MW. Since the first criticality was achieved on January 28, 1965, JRR-4 has been used for shielding experiments, radioisotope production, neutron activation analyses, training for reactor engineers and so on for about 30 years. Within the framework of the RERTR Program, the works for conversion to LEU fuel are now under way, and neutronic and thermal-hydraulic calculations emphasizing on safety and performance aspects are being carried out. The design and evaluation for the core conversion are based on the Guides for Safety Design and Evaluation of research and testing reactor facilities in Japan. These results show that the JRR-4 will be able to convert to use LEU fuel without any major design change of core and size of fuel element. LEU silicide fuel (19.75%) will be used and maximum neutron flux in irradiation hole would be slightly decreased from present neutron flux value of 7x10{sup 13}(n/cm{sup 2}/s). The conversion works are scheduled to complete in 1998, including with upgrade of the reactor building and utilization facilities.

  17. The whole-core LEU silicide fuel demonstration in the JMTR

    Energy Technology Data Exchange (ETDEWEB)

    Aso, Tomokazu; Akashi, Kazutomo; Nagao, Yoshiharu [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)] [and others

    1997-08-01

    The JMTR was fully converted to LEU silicide (U{sub 3}Si{sub 2}) fuel with cadmium wires as burnable absorber in January, 1994. The reduced enrichment program for the JMTR was initiated in 1979, and the conversion to MEU (enrichment ; 45%) aluminide fuel was carried out in 1986 as the first step of the program. The final goal of the program was terminated by the present LEU conversion. This paper describes the results of core physics measurement through the conversion phase from MEU fuel core to LEU fuel core. Measured excess reactivities of the LEU fuel cores are mostly in good agreement with predicted values. Reactivity effect and burnup of cadmium wires, therefore, were proved to be well predicted. Control rod worth in the LEU fuel core is mostly less than that in the MEU fuel core. Shutdown margin was verified to be within the safety limit. There is no significant difference in temperature coefficient of reactivity between the MEU and LEU fuel cores. These results verified that the JMTR was successfully and safely converted to LEU fuel. Extension of the operating cycle period was achieved and reduction of spend fuel elements is expected by using the fuel with high uranium density.

  18. Magnesium silicide nanoparticles as a deoxygenation agent for cancer starvation therapy

    Science.gov (United States)

    Zhang, Chen; Ni, Dalong; Liu, Yanyan; Yao, Heliang; Bu, Wenbo; Shi, Jianlin

    2017-05-01

    A material that rapidly absorbs molecular oxygen (known as an oxygen scavenger or deoxygenation agent (DOA)) has various industrial applications, such as in food preservation, anticorrosion of metal and coal deoxidation. Given that oxygen is vital to cancer growth, to starve tumours through the consumption of intratumoral oxygen is a potentially useful strategy in fighting cancer. Here we show that an injectable polymer-modified magnesium silicide (Mg2Si) nanoparticle can act as a DOA by scavenging oxygen in tumours and form by-products that block tumour capillaries from being reoxygenated. The nanoparticles are prepared by a self-propagating high-temperature synthesis strategy. In the acidic tumour microenvironment, the Mg2Si releases silane, which efficiently reacts with both tissue-dissolved and haemoglobin-bound oxygen to form silicon oxide (SiO2) aggregates. This in situ formation of SiO2 blocks the tumour blood capillaries and prevents tumours from receiving new supplies of oxygen and nutrients.

  19. Effect of Current Density on Thermodynamic Properties of Nanocrystalline Palladium Capped Samarium Hydride Thin Film Switchable Mirrors

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar

    2007-01-01

    Full Text Available A 55 nm samarium film capped with a 10 nm palladium overlayer switched from a metallic reflecting to a semiconducting, transparent in visible state during ex-situ hydrogen loading via electrochemical means in 1 M KOH electrolytic aqueous solution at room temperature. The switching between metal to semiconductor was accompanied by measurement of transmittance during hydrogen loading/unloading. The effect of current density on switching and thermodynamic properties was studied between dihydride state (FCC phase and trihydride state (hexagonal phase. From the plateau of partial pressure of hydrogen at x=2.6, enthalpy of formation was calculated at different current densities. The diffusion coefficients and switching kinetics are shown to depend on applied current density.

  20. Targeted bone marrow radioablation with 153Samarium-lexidronam promotes allogeneic hematopoietic chimerism and donor-specific immunologic hyporesponsiveness.

    Science.gov (United States)

    Inverardi, Luca; Linetsky, Elina; Pileggi, Antonello; Molano, R Damaris; Serafini, Aldo; Paganelli, Giovanni; Ricordi, Camillo

    2004-03-15

    Transplantation tolerance, defined as acceptance of a graft by an otherwise fully immunocompetent host, has been an elusive goal. Although robust tolerance has been achieved by the induction of stable hematopoietic chimerism after bone marrow transplantation, lethal or sublethal radiation conditioning used to induce long-term chimerism precludes its clinical use. We studied whether targeted delivery of radiation to bone marrow could allow for bone marrow cell (BMC) engraftment, chimerism, and donor-specific tolerance in the absence of the side effects associated with external irradiation. We administered a radioactive bone-seeking compound (Samarium-Lexidronam, Quadramet, Berlex Laboratories, Wayne, NJ) together with transient T-cell costimulatory blockade to recipient mice. Allogeneic BMCs were given 7 or 14 days after preconditioning. Costimulatory blockade was obtained by the use of an anti-CD154 antibody for 4 weeks. Chimerism was assessed by flow cytometry. Mice then received donor-specific and third-party skin grafts. Graft survival was analyzed with mechanisms of donor-specific hyporesponsiveness. High levels of stable chimerism across an allogeneic barrier were achieved in mice by a single administration of Samarium-Lexidronam, transient T-cell costimulatory blockade, and BMC transplantation. A large percentage of chimeric animals retained donor-derived skin grafts for more than 120 days without requiring additional immunosuppression, suggesting that harsh cytotoxic preconditioning is not necessary to achieve stable chimerism and donor specific hyporesponsiveness. Analysis of the T-cell repertoire in chimeras indicates T-cell deletional mechanisms. These data broaden the potential use of BMC transplantation for tolerance induction and argue for its potential in treating autoimmune diseases.

  1. Analysis of Channel Stress Induced by NiPt-Silicide in Metal-Oxide-Semiconductor Field-Effect Transistor and Its Generation Mechanism

    Science.gov (United States)

    Mizuo, Mariko; Yamaguchi, Tadashi; Kudo, Shuichi; Hirose, Yukinori; Kimura, Hiroshi; Tsuchimoto, Jun-ichi; Hattori, Nobuyoshi

    2013-09-01

    Channel stress induced by NiPt-silicide films in metal-oxide-semiconductor field-effect transistors (MOSFETs) was demonstrated using UV-Raman spectroscopy, and its generation mechanism was revealed. It was possible to accurately measure the channel stress with the Raman test structure. The channel stress depends on the source/drain doping type and the second silicide annealing method. In order to discuss the channel stress generation mechanism, NiPt-silicide microstructure analyses were performed using X-ray diffraction analysis and scanning transmission electron microscopy. The channel stress generation mechanism can be elucidated by the following two factors: the change in the NiSi lattice spacing, which depends on the annealing temperature, and the NiSi crystal orientation. The analyses of these factors are important for controlling channel stress in stress engineering for high-performance transistors.

  2. Sorption of samarium in soils: influence of soil properties and Sm concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Guinart, Oriol; Salaberria, Aitor; Rigol, Anna; Vidal, Miquel [Analytical Chemistry department, Faculty of Chemistry, University of Barcelona, Marti i Franques 1-11, 08028, Barcelona (Spain)

    2014-07-01

    Due to the fact that barriers of Deep Geological Repositories (DGR) may lose efficiency before the radioisotopes present in the High Level Radioactive Waste (HLRW) completely decay, it is possible that, in the long-term, radioactive leachates may escape from the DGR and reach the soil and water compartments in the biosphere. Therefore, it is required to examine the interaction and mobility of radionuclides present in the HLRW, or their chemical analogues, to predict the impact of their eventual incorporation in the biosphere and to assess the derived risk. Although relevant data have been recently obtained for a few radionuclides in soils, there are still some important gaps for some radionuclides, such us for samarium (Sm). Sm is a lanthanide that, besides being considered as a natural analogue of actinides, may also be present in HLRW in the form of the radioactive isotope {sup 151}Sm. The main objective of this work was to obtain sorption data (K{sub d}) of {sup 151}Sm gathered from a set of soil samples physicochemical fully-characterized (pH, texture, cationic exchange capacity, soil solution cationic composition, organic matter, carbonate and metallic oxides content, etc.). Additionally, as an alternative for testing sorption capacity of radionuclides in soils is the use of the corresponding stable isotope or a chemical analogue, the influence of Sm concentration was also checked. To evaluate {sup 151}Sm sorption, batch assays were carried out for each soil sample, which consisted in a pre-equilibration step of 2 g of each soil with 50 ml of double deionised water, and a subsequent equilibration step with the same solution, but labelled with {sup 151}Sm. The activity of {sup 151}Sm in initial and final solutions was measured by liquid scintillation and K{sub d} ({sup 151}Sm) data were calculated. The reversibly sorbed fraction was estimated by the application of a single extraction test, with double deionised water, to soil residues coming from the previous

  3. Steady-state thermal hydraulic analysis and flow channel blockage accident analysis of JRR-4 silicide LEU core

    Energy Technology Data Exchange (ETDEWEB)

    Kaminaga, Masanori; Yamamoto, Kazuyoshi; Watanabe, Shukichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-09-01

    JRR-4 is a light water moderated and cooled, graphite reflected pool type research reactor using high enriched uranium (HEU) plate-type fuels. Its thermal power is 3.5 MW. The core conversion program from HEU fuel to uranium-silicon-aluminum (U{sub 3}Si{sub 2}-Al) dispersion type fuel (Silicide fuel) with low enriched uranium (LEU) is currently conducted at the JRR-4. This report describes about the steady-state thermal hydraulic analysis results and the flow channel blockage accident analysis result. In JRR-4, there are two operation mode. One is high power operation mode up to 3.5 MW, under forced convection cooling using the primary and the secondary cooling systems. The other is low power operation mode up to 200 kW, under natural circulation cooling between the reactor core and the reactor pool without the primary and the secondary cooling systems. For the analysis of the high power operation mode under forced convection cooling and the flow channel blockage accident, COOLOD code was used. On the other hand, for the analysis of low power operation under natural convection cooling, COOLOD-N2 code was used. From steady-state thermal hydraulic analysis results of both forced and natural convection cooling, fuel temperature, minimum DNBR etc. meet the design criteria and JRR-4 LEU silicide core has enough safety margin under normal operation conditions. Furthermore, flow channel blockage accident analysis results show that one channel flow blockage accident meet the safety criteria for accident conditions which have been established for JRR-4 LEU silicide core. (author)

  4. Physical properties of ternary silicide superconductors Li2XSi3 (X = Rh, Os): An ab initio study

    Science.gov (United States)

    Alam, M. A.; Zilani, M. A. K.; Parvin, F.; Hadi, M. A.

    2017-08-01

    An ab initio method, based on the plane wave pseudopotential and the generalized gradient approximation (GGA), is performed to investigate the physical properties such as structural, elastic, electronic and bonding properties of newly synthesized Li2RhSi3 and predicted Li2OsSi3 ternary silicide superconductors for the first time. Both of these compounds are mechanically stable and are brittle in nature. They also have good machinability. Electronic band structures reveal that these compounds have metallic characteristics. They possess complex bonding nature (metallic, covalent and ionic). According to theoretical Vickers hardness, Li2RhSi3 is softer than Li2OsSi3.

  5. Development of silicide coating over molybdenum based refractory alloy and its characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, S.P., E-mail: spc@barc.gov.i [Materials Processing Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Banerjee, S.; Sharma, I.G.; Suri, A.K. [Materials Processing Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India)

    2010-08-15

    Molybdenum based refractory alloys are potential candidate materials for structural applications in high temperature compact nuclear reactors and fusion reactors. However, these alloys being highly susceptible to oxidation in air or oxygen at elevated temperature, undergoes severe losses from highly volatile molybdenum trioxide species. Present investigation, therefore, examines the feasibility of development of silicide type of coating over molybdenum base TZM alloy shape (Mo > 99 wt.%) using pack cementation coating technique. TZM alloy was synthesized in this laboratory from oxide intermediates of MoO{sub 2}, TiO{sub 2} and ZrO{sub 2} in presence of requisite amount of carbon, by alumino-thermic reduction smelting technique. The arc melted and homogenized samples of TZM alloy substrate was then embedded in the chosen and intimately mixed pack composition consisting of inert matrix (Al{sub 2}O{sub 3}), coating powder (Si) and activator (NH{sub 4}Cl) taken in the judicious proportion. The sealed charge packs contained in an alumina crucible were heated at temperatures of 1000 {sup o}C for 8-16 h heating cycle to develop the coating. The coating phase was confirmed to be of made of MoSi{sub 2} by XRD analysis. The morphology of the coating was studied by SEM characterization. It had revealed that the coating was diffusion bonded where Si from coating diffused inward and Mo from TZM substrate diffused outward to form the coating. The coating was found to be resistant to oxidation when tested in air up to 1200 {sup o}C. A maximum 100 {mu}m of coating thickness was achieved on each side of the substrate.

  6. Rate Theory Modeling and Simulation of Silicide Fuel at LWR Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinbin [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Ye, Bei [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Hofman, Gerard [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Yacout, Abdellatif [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gamble, Kyle [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation; Mei, Zhi-Gang [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-08-29

    As a promising candidate for the accident tolerant fuel (ATF) used in light water reactors (LWRs), the fuel performance of uranium silicide (U3Si2) at LWR conditions needs to be well understood. In this report, rate theory model was developed based on existing experimental data and density functional theory (DFT) calculations so as to predict the fission gas behavior in U3Si2 at LWR conditions. The fission gas behavior of U3Si2 can be divided into three temperature regimes. During steady-state operation, the majority of the fission gas stays in intragranular bubbles, whereas the dominance of intergranular bubbles and fission gas release only occurs beyond 1000 K. The steady-state rate theory model was also used as reference to establish a gaseous swelling correlation of U3Si2 for the BISON code. Meanwhile, the overpressurized bubble model was also developed so that the fission gas behavior at LOCA can be simulated. LOCA simulation showed that intragranular bubbles are still dominant after a 70 second LOCA, resulting in a controllable gaseous swelling. The fission gas behavior of U3Si2 at LWR conditions is benign according to the rate theory prediction at both steady-state and LOCA conditions, which provides important references to the qualification of U3Si2 as a LWR fuel material with excellent fuel performance and enhanced accident tolerance.

  7. Crystal growth of semiorganic complex- samarium chloride coordinated thiourea-L-tartaric acid and its studies on structure and optical characteristics

    Science.gov (United States)

    Slathia, Goldy; Singh, Harjinder; Ramya, E.; Rao, D. Narayana; Bamzai, K. K.

    2017-05-01

    The semi-organic complex of samarium chloride coordinated thiourea-L-tartaric acid (SCTLT) has been grown as a single crystal by slow evaporation technique at room temperature. For structural studies, the grown crystal was subjected to single crystal X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy. Low cut off wavelength and transparent characteristics were explored by UV-VIS optical characterization. Third-order nonlinear optical properties of grown crystal were investigated by Z-scan technique.

  8. Sorption of samarium in iron (II) and (III) phosphates in aqueous systems; Sorcion de samario en fosfatos de hierro (II) y (III) en sistemas acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Diaz F, J.C

    2006-07-01

    The radioactive residues that are stored in the radioactive confinements its need to stay isolated of the environment while the radioactivity levels be noxious. An important mechanism by which the radioactive residues can to reach the environment, it is the migration of these through the underground water. That it makes necessary the investigation of reactive materials that interacting with those radionuclides and that its are able to remove them from the watery resources. The synthesis and characterization of materials that can be useful in Environmental Chemistry are very important because its characteristics are exposed and its behavior in chemical phenomena as the sorption watery medium is necessary to use it in the environmental protection. In this work it was carried out the sorption study of the samarium III ion in the iron (II) and (III) phosphate; obtaining the sorption isotherms in function of pH, of the phosphate mass and of the concentration of the samarium ion using UV-visible spectroscopy to determine the removal percentage. The developed experiments show that as much the ferrous phosphate as the ferric phosphate present a great affinity by the samarium III, for what it use like reactive material in contention walls can be very viable because it sorption capacity has overcome 90% to pH values similar to those of the underground and also mentioning that the form to obtain these materials is very economic and simple. (Author)

  9. Trace amounts of rare earth elements in high purity samarium oxide by sector field inductively coupled plasma mass spectrometry after separation by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Pedreira, W.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil) and Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), 05409-002 Sao Paulo, SP (Brazil)]. E-mail: walter.pedreira@fundacentro.gov.br; Queiroz, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Abrao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Rocha, S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Vasconcellos, M.E. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), 05508-900 Sao Paulo, SP (Brazil); Boaventura, G.R. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil); Pimentel, M.M. [Instituto de Geociencias, Universidade de Brasilia (UnB), 70910-900 Brasilia, DF (Brazil)

    2006-07-20

    Today there is an increasing need for high purity rare earth compounds in various fields, the optical, the electronics, the ceramic, the nuclear and geochemistry. Samarium oxide has special uses in glass, phosphors, lasers and thermoelectric devices. Calcium chloride crystals treated with samarium have been employed in lasers, which produce light beams intense enough to burn metal. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques such as ICP optical emission spectrometry (ICP-OES). In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2 (La) pg mL{sup -1} to 8 (Gd) pg mL{sup -1}. The %R.S.D. of the methods varying between 0.9 and 1.5% for a set of five (n = 5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure samarium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference (MO{sup +} and MOH{sup +})

  10. Thin film properties of sputtered niobium silicide on SiO/sub 2/, Si/sub 3/N/sub 4/, and N/sup +/ poly-Si

    Energy Technology Data Exchange (ETDEWEB)

    Chow, T.P.; Lu, W.J.; Steckl, A.J.; Baliga, B.J.

    1986-01-01

    Thin film properties of niobium silicide sputtered from a slightly silicon-rich (Si/Nb approx. = 2.3), cold-pressed alloy target onto SiO/sub 2/, Si/sub 3/N/sub 4/, and n doped poly-Si have been investigated. The structural and compositional properties were examined with x-ray diffraction, Rutherford backscattering spectrometry (RBS), and secondary ion mass spectrometry (SIMS). X-ray diffraction revealed that NbSi/sub 2/ was the predominant silicide phase present, unlike those films reported previously, which contained significant amounts of an intermediate silicide phase (Nb/sub 5/Si/sub 3/). These films had a SiNb ratio of 2.1 as determined from RBS and contained lower levels of common contaminants (such as N/sub 2/, O/sub 2/, and carbon). Isochronal and isothermal annealing showed that the major decrease in resistivity occurred in the first 5 min, and a resistivity value of approx. =70 ..mu cap omega..-cm was obtained after annealing at 1000/sup 0/C. During annealing, phosphorus was found to diffuse through NbSi/sub 2/ rapidly, similar to other refractory silicides.

  11. Ni and Ni Silicides Ohmic Contacts on N-type 6H-SiC with Medium and Low Doping Level

    Directory of Open Access Journals (Sweden)

    S. Cichon

    2011-04-01

    Full Text Available Ni silicides contacts, which are expected to be advantageous contact materials on SiC, were tested in this work. Prepared contact structures were ohmic with low contact resistivity approximately 8×10-4 Ω cm2 after annealing at 960°C as far as the SiC substrate with a medium doping level was concerned, no matter whether Ni or Ni silicides were used. At lower annealing temperatures, only Schottky behavior was observed by means of I-V characteristics measurements. In the case of SiC substrate with a low doping level, the behavior differed. It was necessary to anneal the structures at 1070°C to see ohmic behavior appearing with resistivities reaching 8×10-3 Ω cm2 and this was valid only for Ni and Ni2Si. Raman spectroscopy measurements confirmed formation of single Ni silicides as expected. It was found that Ni silicides can keep as good resistivity as Ni contacts while they interact with SiC in limited way and their undesirable drop-like morphology is expected to be overcome for example with a covering layer.

  12. Formation and thermal stability of Ti-capped Co-silicide from Co-Ta alloy films on (100) Si and polycrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Joo; Choi, Hyo Jick; Ko, Dae Hong [Yonsei Univ., Seoul (Korea, Republic of); Ku, Ja Hum; Choi, Si Young; Fujihara, Kazuyuki [Samsung Electronics Co., Ltd., Yongin (Korea, Republic of); Yang, Cheol Woong [Sungkyunkwan Univ., Suwon (Korea, Republic of)

    2002-04-01

    Co-Ta alloy films were deposited on (100) single-crystalline and polycrystalline silicon substrates by using DC magnetron sputtering. The interfacial reactions between the Co-Ta alloy films and the silicon substrates were investigated in the temperature range of 500 {approx} 820 degree C by using rapid thermal annealing in an N{sub 2} ambient. In contrast to the Co/si system, we observed that the formation of Co-silicide and the transformation from the high resistivity CoSi phase to the low resistivity CoSi{sub 2} phase in the Co-Ta/Si system occurred at higher temperatures than it did in the Co/Si system. The Co-silicide films on Si and poly-Si substrates formed from Co-Ta alloy films maintained low sheet resistance values upon high temperature annealing while those of Co-silicide films from the Co/Si system increased significantly. The improvement in the thermal stability of the Co-silicide films formed from Co-Ta alloy films is due to the formation of Ta-compounds, such as the TaSi{sub 2} phase, at the grain boundaries and at the surfaces of the CoSi{sub 2} films.

  13. Narrow bandgap semiconducting silicides: Intrinsic infrared detectors on a silicon chip

    Science.gov (United States)

    Mahan, John E.

    1990-01-01

    Work done during the final report period is presented. The main technical objective was to achieve epitaxial growth on silicon of two semiconducting silicides, ReSi2 and CrSi2. ReSi2 thin films were grown on (001) silicon wafers by vacuum evaporation of rhenium onto hot substrates in ultrahigh vacuum. The preferred epitaxial relationship was found to be ReSi2(100)/Si(001) with ReSi2(010) parallel to Si(110). The lattice matching consists of a common unit mesh of 120 A(sup 2) area, and a mismatch of 1.8 percent. Transmission electron microscopy revealed the existence of rotation twins corresponding to two distinct but equivalent azimuthal orientations of the common unit mesh. MeV He(+) backscattering spectrometry revealed a minimum channeling yield of 2 percent for an approximately 1,500 A thick film grown at 650 C. Although the lateral dimension of the twins is on the order of 100 A, there is a very high degree of alignment between the ReSi2(100) and the Si(001) planes. Highly oriented films of CrSi2 were grown on (111) silicon substrates, with the matching crystallographic faces being CrSi2(001)/Si(111). The reflection high-energy electron diffraction (RHEED) patterns of the films consist of sharp streaks, symmetrically arranged. The predominant azimuthal orientation of the films was determined to be CrSi2(210) parallel to Si(110). This highly desirable heteroepitaxial relationship has been obtained previously by others; it may be described with a common unit mesh of 51 A(sup 2) and mismatch of 0.3 percent. RHEED also revealed the presence of limited film regions of a competing azimuthal orientation, CrSi2(110) parallel to Si(110). A channeling effect for MeV He(+) ions was not found for this material. Potential commercial applications of this research may be found in silicon-integrated infrared detector arrays. Optical characterizations showed that semiconducting ReSi2 is a strong absorber of infrared radiation, with the adsorption constant increasing above 2 x

  14. Oxidation at through-hole defects in fused slurry silicide coated columbium alloys FS-85 and Cb-752

    Science.gov (United States)

    Levine, S. R.

    1973-01-01

    Metal recession and interstitial contamination at 0.08-centimeter-diameter through-hole intentional defects in fused slurry silicide coated FS-85 and Cb-752 columbium alloys were studied to determine the tolerance of these materials to coating defects. Five external pressure reentry simulation exposures to 1320 C and 4.7 x 1,000 N/sq m (maximum pressure) resulted in a consumed metal zone having about twice the initial defect diameter for both alloys with an interstitial contamination zone extending about three to four initial defect diameters. Self-healing occurred in the 1.33 x 10 N/sq m, 1320 C exposures and to a lesser extent in internal pressure reentry cycles to 1320 C and 1.33 x 100 N/sq m (maximum pressure).

  15. Interdiffusion and growth of chromium silicide at the interface of Cr/Si(As) system during rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Benkherbache, H. [Universite de M' Sila, (28000) M' Sila (Algeria); Merabet, A., E-mail: merabet_abdelali@yahoo.f [Laboratoire Physique et Mecanique des Materiaux Metalliques, Departement d' O.M.P., Faculte des Sciences de l' Ingenieur, Universite de Setif, (19000) Setif (Algeria)

    2010-02-26

    In this work, the solid-state reaction between a thin film of chromium and silicon has been studied using Rutherford backscattering spectroscopy, X-ray diffraction and the sheet resistance measurements. The thickness of 100 nm chromium layer has been deposited by electronic bombardment on Si (100) substrates, part of them had previously been implanted with arsenic ions of 10{sup 15} at/cm{sup 2} doses and an energy of 100 keV. The samples were heat treated under rapid thermal annealing at 500 {sup o}C for time intervals ranging from 15 to 60 s. The rapid thermal annealing leads to a reaction at the interface Cr/Si inducing the formation and the growth of the unique silicide CrSi{sub 2}, but no other phase can be detected. For samples implanted with arsenic, the saturation value of the sheet resistance is approximately 1.5 times higher than for the non-implanted case.

  16. Effectiveness of radiation synovectomy with samarium-{sup 153} particulate hydroxyapatite in rheumatoid arthritis patients with knee synovitis: a controlled randomized double-blind trial

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Marla Francisca dos; Furtado, Rita Nely Vilar; Konai, Monique Sayuri; Natour, Jamil, E-mail: jnatour@unifesp.b [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Divisao de Reumatologia; Castiglioni, Mario Luiz Vieira; Marchetti, Renata Rosa [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil). Divisao de Medicina Nuclear

    2009-07-01

    Objectives: the aim of the present study was to investigate the effectiveness of Samarium{sup 153}-particulate hydroxyapatite radiation synovectomy in rheumatoid arthritis patients with chronic knee synovitis. Methods: fifty-eight rheumatoid arthritis patients (60 knees) with chronic knee synovitis participated in a controlled double-blinded trial. Patients were randomized to receive either an intra-articular injection with 40 mg triamcinolone hexacetonide alone (TH group) or 40 mg triamcinolone hexacetonide combined with 15 mCi Samarium{sup 153}-particulate hydroxyapatite (Sm/TH group). Blinded examination at baseline (T0) and at 1 (T1), 4 (T4), 12 (T12), 32 (T32), and 48 (T48) weeks post-intervention were performed on all patients and included a visual analog scale for joint pain and swelling as well as data on morning stiffness, flexion, extension, knee circumference, Likert scale of improvement, percentage of improvement, SF-36 generic quality of life questionnaire, Stanford Health Assessment Questionnaire (HAQ), Lequesne index, use of non-steroidal anti-inflammatory drugs or oral corticosteroids, events and adverse effects, calls to the physician, and hospital visits. Results: the sample was homogeneous at baseline, and there were no withdrawals. Improvement was observed in both groups in relation to T0, but no statistically significant differences between groups were observed regarding all variables at the time points studied. The Sm/TH group exhibited more adverse effects at T1 (p<0.05), but these were mild and transitory. No severe adverse effects were reported during follow-up. Conclusion: intra-articular injection of Samarium{sup 153}-particulate hydroxyapatite (15 mCi) with 40 mg of triamcinolone hexacetonide is not superior to triamcinolone hexacetonide alone for the treatment of knee synovitis in patients with rheumatoid arthritis at 1 y of follow-up. (author)

  17. The properties of samarium-doped zinc oxide/phthalocyanine structure for optoelectronics prepared by pulsed laser deposition and organic molecular evaporation

    Czech Academy of Sciences Publication Activity Database

    Novotný, Michal; Marešová, Eva; Fitl, Přemysl; Vlček, Jan; Bergmann, M.; Vondráček, Martin; Yatskiv, Roman; Bulíř, Jiří; Hubík, Pavel; Hruška, Petr; Drahokoupil, Jan; Abdellaoui, N.; Vrňata, M.; Lančok, Ján

    2016-01-01

    Roč. 122, č. 3 (2016), 1-8, č. článku 225. ISSN 0947-8396 R&D Projects: GA MŠk(CZ) LG15050; GA ČR(CZ) GAP108/11/0958; GA MŠk(CZ) LM2011029; GA ČR(CZ) GA14-10279S; GA MŠk(CZ) 7AMB14FR010 Institutional support: RVO:68378271 ; RVO:67985882 Keywords : samarium-doped zinc oxide zinc/phthalocyanine deposition * evaporation * pulsed laser deposition * thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.455, year: 2016

  18. Neutron Activated Samarium-153 Microparticles for Transarterial Radioembolization of Liver Tumour with Post-Procedure Imaging Capabilities

    Science.gov (United States)

    Hashikin, Nurul Ab. Aziz; Yeong, Chai-Hong; Abdullah, Basri Johan Jeet; Ng, Kwan-Hoong; Chung, Lip-Yong; Dahalan, Rehir; Perkins, Alan Christopher

    2015-01-01

    Introduction Samarium-153 (153Sm) styrene divinylbenzene microparticles were developed as a surrogate for Yttrium-90 (90Y) microspheres in liver radioembolization therapy. Unlike the pure beta emitter 90Y, 153Sm possess both therapeutic beta and diagnostic gamma radiations, making it possible for post-procedure imaging following therapy. Methods The microparticles were prepared using commercially available cation exchange resin, Amberlite IR-120 H+ (620–830 μm), which were reduced to 20–40 μm via ball mill grinding and sieve separation. The microparticles were labelled with 152Sm via ion exchange process with 152SmCl3, prior to neutron activation to produce radioactive 153Sm through 152Sm(n,γ)153Sm reaction. Therapeutic activity of 3 GBq was referred based on the recommended activity used in 90Y-microspheres therapy. The samples were irradiated in 1.494 x 1012 n.cm-2.s-1 neutron flux for 6 h to achieve the nominal activity of 3.1 GBq.g-1. Physicochemical characterisation of the microparticles, gamma spectrometry, and in vitro radiolabelling studies were carried out to study the performance and stability of the microparticles. Results Fourier Transform Infrared (FTIR) spectroscopy of the Amberlite IR-120 resins showed unaffected functional groups, following size reduction of the beads. However, as shown by the electron microscope, the microparticles were irregular in shape. The radioactivity achieved after 6 h neutron activation was 3.104 ± 0.029 GBq. The specific activity per microparticle was 53.855 ± 0.503 Bq. Gamma spectrometry and elemental analysis showed no radioactive impurities in the samples. Radiolabelling efficiencies of 153Sm-Amberlite in distilled water and blood plasma over 48 h were excellent and higher than 95%. Conclusion The laboratory work revealed that the 153Sm-Amberlite microparticles demonstrated superior characteristics for potential use in hepatic radioembolization. PMID:26382059

  19. Effect of P{sup +} ions on the microstructure and the nature of the formed silicides in the Cr/Si system

    Energy Technology Data Exchange (ETDEWEB)

    Mirouh, K. [Laboratoire des Couches Minces et Interfaces, Departement de Physique, Universite de Constantine, Campus chaab Errassas, Constantine 25000 (Algeria)]. E-mail: mirouh.kamel@caramail.com; Bouabellou, A. [Laboratoire des Couches Minces et Interfaces, Departement de Physique, Universite de Constantine, Campus chaab Errassas, Constantine 25000 (Algeria); Halimi, R. [Laboratoire des Couches Minces et Interfaces, Departement de Physique, Universite de Constantine, Campus chaab Errassas, Constantine 25000 (Algeria); Karaali, A. [Laboratoire des Couches Minces et Interfaces, Departement de Physique, Universite de Constantine, Campus chaab Errassas, Constantine 25000 (Algeria); Mosser, A. [IPCMS-GSI, 23 rue du Loess, F-67037 Strasbourg (France); Ehret, G. [IPCMS-GSI, 23 rue du Loess, F-67037 Strasbourg (France)

    2004-12-15

    The effect of the phosphorus on the microstructure and on the nature of the formed silicide in the annealed Cr/Si system is studied. The chromium layer is deposited by electron gun evaporation on the undoped and P{sup +} doped monocrystalline silicon. Cross-sectional transmission electron microscopy (XTEM) investigation of the samples, annealed at 475 deg. C for different times, shows that the presence of phosphorus leads to the formation of CrSi{sub 2} disilicide, free of defects, and Cr{sub 3}Si silicide for lower and higher annealing times, respectively. In the case of undoped substrate the formed CrSi{sub 2} disilicide is stable and contains a high concentration of stacking faults when the chromium is partially consumed.

  20. Vertically grown multiwalled carbon nanotube anode and nickel silicide integrated high performance microsized (1.25 μl) microbial fuel cell

    KAUST Repository

    Mink, Justine E.

    2012-02-08

    Microbial fuel cells (MFCs) are an environmentally friendly method for water purification and self-sustained electricity generation using microorganisms. Microsized MFCs can also be a useful power source for lab-on-a-chip and similar integrated devices. We fabricated a 1.25 μL microsized MFC containing an anode of vertically aligned, forest type multiwalled carbon nanotubes (MWCNTs) with a nickel silicide (NiSi) contact area that produced 197 mA/m 2 of current density and 392 mW/m 3 of power density. The MWCNTs increased the anode surface-to-volume ratio, which improved the ability of the microorganisms to couple and transfer electrons to the anode. The use of nickel silicide also helped to boost the output current by providing a low resistance contact area to more efficiently shuttle electrons from the anode out of the device. © 2012 American Chemical Society.

  1. Behavior of silicon in nitric media. Application to uranium silicides fuels reprocessing; Comportement du silicium en milieu nitrique. Application au retraitement des combustibles siliciures d'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Cheroux, L

    2001-07-01

    Uranium silicides are used in some research reactors. Reprocessing them is a solution for their cycle end. A list of reprocessing scenarios has been set the most realistic being a nitric dissolution close to the classic spent fuel reprocessing. This uranium silicide fuel contains a lot of silicon and few things are known about polymerization of silicic acid in concentrated nitric acid. The study of this polymerization allows to point out the main parameters: acidity, temperature, silicon concentration. The presence of aluminum seems to speed up heavily the polymerization. It has been impossible to find an analytical technique smart and fast enough to characterize the first steps of silicic acid polymerization. However the action of silicic species on emulsions stabilization formed by mixing them with an organic phase containing TBP has been studied, Silicon slows down the phase separation by means of oligomeric species forming complex with TBP. The existence of these intermediate species is short and heating can avoid any stabilization. When non irradiated uranium silicide fuel is attacked by a nitric solution, aluminum and uranium are quickly dissolved whereas silicon mainly stands in solid state. That builds a gangue of hydrated silica around the uranium silicide particulates without preventing uranium dissolution. A small part of silicon passes into the solution and polymerize towards the highly poly-condensed forms, just 2% of initial silicon is still in molecular form at the end of the dissolution. A thermal treatment of the fuel element, by forming inter-metallic phases U-Al-Si, allows the whole silicon to pass into the solution and next to precipitate. The behavior of silicon in spent fuels should be between these two situations. (author)

  2. Morphological and electrical properties of self-assembled iron silicide nanoparticles on Si(0 0 1) and Si(1 1 1) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Molnár, G., E-mail: molnargy@mfa.kfki.hu; Dózsa, L.; Erdélyi, R.; Vértesy, Z.; Osváth, Z.

    2015-12-01

    Highlights: • Epitaxial iron silicide nanostructures were grown on Si(1 1 1) and Si(0 0 1) substrates. • The size and shape of the particles are the function of the thickness and annealing. • The local current–voltage characteristics were measured by conductive AFM. • The different size and shape nanoparticles show similar I–V characteristics. • The tip current is dominated in few nm size sites, visible in the AFM phase image. - Abstract: Epitaxial iron silicide nanostructures are grown by solid phase epitaxy on Si(0 0 1) and Si(1 1 1), and by reactive deposition epitaxy on Si(0 0 1) substrates. The formation process is monitored by reflection high-energy electron diffraction. The morphology, size, and electrical properties of the nanoparticles are investigated by scanning electron microscopy, by electrically active scanning probe microscopy, and by confocal Raman spectroscopy. The results show that the shape, size, orientation, and density of the nanoobjects can be tuned by self-assembly, controlled by the lattice misfit between the substrates and iron silicides. The size distribution and shape of the grown nanoparticles depend on the substrate orientation, on the initial thickness of the evaporated iron, on the temperature and time of the annealing, and on the preparation method. The so-called Ostwald ripening phenomena, which state that the bigger objects develop at the expense of smaller ones, controls the density of the nanoparticles. Raman spectra show the bigger objects do not contain β-FeSi{sub 2} phase. The different shape nanoparticles exhibit small, about 100 mV barrier compared to the surrounding silicon. The local leakage current of the samples measured by conductive AFM using a Pt coated Si tip is localized in a few nanometers size sites, and the sites which we assume are very small silicide nanoparticles or point defects.

  3. Simultaneous aluminizing and chromizing of steels to form (Fe,Cr){sub 3}Al coatings and Ge-doped silicide coatings of Cr-Zr base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, M.; He, Y.R.; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    1997-12-01

    A halide-activated cementation pack involving elemental Al and Cr powders has been used to achieve surface compositions of approximately Fe{sub 3}Al plus several percent Cr for low alloy steels (T11, T2 and T22) and medium carbon steel (1045 steel). A two-step treatment at 925 C and 1150 C yields the codeposition and diffusion of aluminum and chromium to form dense and uniform ferrite coatings of about 400 {micro}m thickness, while preventing the formation of a blocking chromium carbide at the substrate surfaces. Upon cyclic oxidation in air at 700 C, the coated steel exhibits a negligible 0.085 mg/cm{sup 2} weight gain for 1900 one-hour cycles. Virtually no attack was observed on coated steels tested at ABB in simulated boiler atmospheres at 500 C for 500 hours. But coatings with a surface composition of only 8 wt% Al and 6 wt% Cr suffered some sulfidation attack in simulated boiler atmospheres at temperatures higher than 500 C for 1000 hours. Two developmental Cr-Zr based Laves phase alloys (CN129-2 and CN117(Z)) were silicide/germanide coated. The cross-sections of the Ge-doped silicide coatings closely mimicked the microstructure of the substrate alloys. Cyclic oxidation in air at 1100 C showed that the Ge-doped silicide coating greatly improved the oxidation resistance of the Cr-Zr based alloys.

  4. Preparation and examination of properties of samarium-153-EDTMP complex; Otrzymywanie chelatu kwasu etylenodiaminotetrametylenofosfonowego (EDTMP) z samarem-153 i badanie jego wlasciwosci

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, M. [Institute of Atomic Energy, Otwock-Swierk (Poland); Garnuszek, P.; Lukasiewicz, A.; Wozniak, I.; Zulczyk, W. [Osrodek Badawczo-Rozwojowy Izotopow, Otwock-Swierk (Poland); Licinska, I. [Instytut Lekow, Warsaw (Poland)

    1995-12-31

    Preparation and properties of ethylenediaminetetramethylenephosphonic acid (EDTMP) as well as some properties of {sup 153}Sm-EDTMP chelate have been examined. The chelate formed by samarium-153 (46.3 h, {beta}{sup -}-decay) with EDTMP exhibits high bone uptake and can be used for treatment of disseminated, painful skeletal metastases. The purity and stability of solutions of {sup 153}Sm-EDTMP chelate were examined in a broad range of samarium concentration and {sup 153}Sm specific activity. The complex under study was examined by radio-TLC, -electrophoresis and radio-HPLC. The results obtained suggest the small size of molecules of {sup 153}Sm-EDTMP chelate as compared with molecules of ``free``EDTMP. The results of biodistribution of {sup 153}Sm-EDTMP determined in rats indicate the quick blood clearance, high deposition of radioactivity in bone and quick excretion of radioactivity into urine. No specific uptake of {sup 153}Sm-EDTMP in extra-skeletal organs was found. (author). 42 refs, 13 figs, 22 tabs.

  5. The Level of Europium-154 Contaminating Samarium-153-EDTMP Activates the Radiation Alarm System at the US Homeland Security Checkpoints

    Directory of Open Access Journals (Sweden)

    Mohammed Najeeb Al Hallak

    2009-08-01

    Full Text Available 153Sm-EDTMP is a radiopharmaceutical composed of EDTMP (ethylenediamine-tetramethylenephosphonate and Samarium-153 [1]. 153Sm-EDTMP has an affinity for skeletal tissue and concentrates in areas with increased bone turnover; thus, it is successfully used in relieving pain related to diffuse bone metastases [1]. The manufacturing process of 153Sm-EDTMP leads to contamination with 154Eu (Europium-154 [2]. A previous study only alluded to the retention of 154Eu in the bones after receiving treatment with 153Sm-EDTMP [2]. Activation of the alarm at security checkpoints after 153Sm-EDTMP therapy has not been previously reported. Two out of 15 patients who received 153Sm-EDTMP at Roger Maris Cancer Center (Fargo, N. Dak., USA activated the radiation activity sensors while passing through checkpoints; one at a US airport and the other while crossing theAmerican-Canadian border. We assume that the 154Eu which remained in the patients’ bones activated the sensors. Methods: In order to investigate this hypothesis, we obtained the consent from 3 of our 15 patients who received 153Sm-EDTMP within the previous 4 months to 2 years, including the patient who had activated the radiation alarm at the airport. The patients were scanned with a handheld detector and a gamma camera for energies from 511 keV to 1.3 MeV. Results: All three patients exhibited identical spectral images, and further analysis showed that the observed spectra are the result of 154Eu emissions. Conclusion: Depending on the detection thresholds and windows used by local and federal authorities, the remaining activity of 154Eu retained in patients who received 153Sm-EDTMP could be sufficient enough to increase the count rates above background levels and activate the sensors. At Roger Maris Cancer Center, patients are now informed of the potential consequences of 153Sm-EDTMP therapy prior to initiating treatment. In addition, patients treated with 153Sm-EDTMP at Roger Maris Cancer Center

  6. The Level of Europium-154 Contaminating Samarium-153-EDTMP Activates the Radiation Alarm System at the US Homeland Security Checkpoints.

    Science.gov (United States)

    Najeeb Al Hallak, Mohammed; McCurdy, Matt; Zouain, Nicolas; Hayes, Justin

    2009-08-28

    (153)Sm-EDTMP is a radiopharmaceutical composed of EDTMP (ethylenediamine-tetramethylenephosphonate) and Samarium-153 [1]. (153)Sm-EDTMP has an affinity for skeletal tissue and concentrates in areas with increased bone turnover; thus, it is successfully used in relieving pain related to diffuse bone metastases [1]. The manufacturing process of (153)Sm-EDTMP leads to contamination with (154)Eu (Europium-154) [2]. A previous study only alluded to the retention of (154)Eu in the bones after receiving treatment with (153)Sm-EDTMP [2]. Activation of the alarm at security checkpoints after (153)Sm-EDTMP therapy has not been previously reported. Two out of 15 patients who received (153)Sm-EDTMP at Roger Maris Cancer Center (Fargo, N. Dak., USA) activated the radiation activity sensors while passing through checkpoints; one at a US airport and the other while crossing the American-Canadian border. We assume that the (154)Eu which remained in the patients' bones activated the sensors. METHODS: In order to investigate this hypothesis, we obtained the consent from 3 of our 15 patients who received (153)Sm-EDTMP within the previous 4 months to 2 years, including the patient who had activated the radiation alarm at the airport. The patients were scanned with a handheld detector and a gamma camera for energies from 511 keV to 1.3 MeV. RESULTS: All three patients exhibited identical spectral images, and further analysis showed that the observed spectra are the result of (154)Eu emissions. CONCLUSION: Depending on the detection thresholds and windows used by local and federal authorities, the remaining activity of (154)Eu retained in patients who received (153)Sm-EDTMP could be sufficient enough to increase the count rates above background levels and activate the sensors. At Roger Maris Cancer Center, patients are now informed of the potential consequences of (153)Sm-EDTMP therapy prior to initiating treatment. In addition, patients treated with (153)Sm-EDTMP at Roger Maris Cancer

  7. Effect of deposition conditions on the structure, phase composition and electrical properties of the chromium silicide films

    Energy Technology Data Exchange (ETDEWEB)

    Trofimov, V I [Institute of Radioengineering and Electronics, 11/7 Mokhovaya Str., 125009 Moscow (Russian Federation); Kim, J [CN-Regional Innovation Agency, 244-19 Songgok-ri, Asan City, 336-813 (Korea, Republic of); Bae, S [University of Incheon, 177 Dohwa-Dong, Incheon City, 402-749 (Korea, Republic of)], E-mail: trof@mail.cplire.ru

    2008-03-15

    Thin chromium silicide films with thickness up to 20 nm were deposited by flash evaporation of CrSi{sub 2} powder onto silica glass and (100) KCl substrates at temperatures from 20 to 550{sup 0}C and analyzed by electrical resistance measurements and transmission electron microscopy. The film phase composition depends crucially on deposition procedure: if a CrSi{sub 2} powder was thermally treated just prior deposition, CrSi{sub 2} film grows otherwise Cr{sub 3}Si film is formed. Under deposition onto unheated substrate an amorphous film grows. A crystalline phase appears at {approx}280 deg. C for CrSi{sub 2} and 250 deg. C for Cr{sub 3}Si and furtheron its fraction increases. The CrSi{sub 2} film consists of densely packed crystallites, whereas Cr{sub 3}Si film structure resembles a network of fine crystallites imbedded into amorphous silicon-based matrix. The resistivity of CrSi{sub 2} film grows with substrate temperature, whereas that of Cr{sub 3}Si film reduces. The observed resistivity - film thickness dependence is well described by the Fuchs-Sondheimer model for CrSi{sub 2} films and Mayadas-Shatzkes model for Cr{sub 3}Si films, since in the formers the crystallites size is larger than a film thickness, whereas in the latter's it is less than a film thickness.

  8. Effect of deposition conditions on the structure, phase composition and electrical properties of the chromium silicide films

    Science.gov (United States)

    Trofimov, V. I.; Kim, J.; Bae, S.

    2008-03-01

    Thin chromium silicide films with thickness up to 20 nm were deposited by flash evaporation of CrSi2 powder onto silica glass and (100) KCl substrates at temperatures from 20 to 550°C and analyzed by electrical resistance measurements and transmission electron microscopy. The film phase composition depends crucially on deposition procedure: if a CrSi2 powder was thermally treated just prior deposition, CrSi2 film grows otherwise Cr3Si film is formed. Under deposition onto unheated substrate an amorphous film grows. A crystalline phase appears at ~280°C for CrSi2 and 250°C for Cr3Si and furtheron its fraction increases. The CrSi2 film consists of densely packed crystallites, whereas Cr3Si film structure resembles a network of fine crystallites imbedded into amorphous silicon-based matrix. The resistivity of CrSi2 film grows with substrate temperature, whereas that of Cr3Si film reduces. The observed resistivity - film thickness dependence is well described by the Fuchs-Sondheimer model for CrSi2 films and Mayadas-Shatzkes model for Cr3Si films, since in the formers the crystallites size is larger than a film thickness, whereas in the latter's it is less than a film thickness.

  9. Mechanical properties of thermoelectric n-type magnesium silicide synthesized employing in situ spark plasma reaction sintering

    Science.gov (United States)

    Muthiah, Saravanan; Singh, R. C.; Pathak, B. D.; Dhar, Ajay

    2017-07-01

    Thermoelectric devices employing magnesium silicide (Mg2Si) offer an inexpensive and non-toxic solution for green energy generation compared to other existing conventional thermoelectric materials in the mid-temperature range. However, apart from the thermoelectric performance, their mechanical properties are equally important in order to avoid the catastrophic failure of their modules during actual operation. In the present study, we report the synthesis of Mg2Si co-doped with Bi and Sb employing in situ spark plasma reaction sintering and investigate its broad range of mechanical properties. The mechanical properties of the sintered co-doped Mg2Si suggest a significantly enhanced value of hardness ~5.4  ±  0.2 GPa and an elastic modulus ~142.5  ±  6 GPa with a fracture toughness of ~1.71  ±  0.1 MPa  √m. The thermal shock resistance, which is one of the most vital parameter for designing thermoelectric devices, was found to be ~300 W m-1, which is higher than most of the other existing state-of-the-art mid-temperature thermoelectric materials. The friction and wear characteristics of sintered co-doped Mg2Si have been reported for the first time, in order to realize the sustainability of their thermoelectric modules under actual hostile environmental conditions.

  10. Formation of a new adduct based on fullerene tris-malonate samarium salt C60-[C60(=C(COO)2)3]Sm2

    Science.gov (United States)

    Petrov, A. A.; Keskinov, V. A.; Semenov, K. N.; Charykov, N. A.; Letenko, D. G.; Nikitin, V. A.

    2017-03-01

    Gram quantities of a new adduct based on light fullerene tris-malonate samarium salt C60 [C60(=C(COO)2)3]Sm2 are obtained via the reaction of ion exchange. The obtained adduct is studied by means of electron and infrared spectroscopy, X-ray and elemental analysis, electron microscopy, and thermogravimetry. The polythermal solubility of [C60(=C(COO)2)3]Sm2 in water is determined in ampoules via saturation within 20-70°C. The composition of crystalline hydrate [C60(=C(COO)2)3]Sm2 · 36H2O, which exists in equilibrium with the saturated solution, is estimated.

  11. Biodistribution of samarium-153-EDTMP in rats treated with docetaxel Biodistribuição de EDTMP-153-samário em ratos tratados com docetaxel

    Directory of Open Access Journals (Sweden)

    Arthur Villarim Neto

    2009-02-01

    Full Text Available PURPOSE: Many patients with metastatic bone disease have to use radiopharmaceuticals associated with chemotherapy to relieve bone pain. The aim of this study was to assess the influence of docetaxel on the biodistribution of samarium-153-EDTMP in bones and other organs of rats. METHODS: Wistar male rats were randomly allocated into 2 groups of 6 rats each. The DS (docetaxel/samarium group received docetaxel (15 mg/kg intraperitoneally in two cycles 11 days apart. The S (samarium/control group rats were not treated with docetaxel. Nine days after chemotherapy, all the rats were injected with 0.1ml of samarium-153-EDTMP via orbital plexus (25µCi. After 2 hours, the animals were killed and samples of the brain, thyroid, lung, heart, stomach, colon, liver, kidney and both femurs were removed. The percentage radioactivity of each sample (% ATI/g was determined in an automatic gamma-counter (Wizard-1470, Perkin-Elmer, Finland. RESULTS: On the 9th day after the administration of the 2nd chemotherapy cycle, the rats had a significant weight loss (314.50±22.09g compared (pOBJETIVO: Muitos pacientes com metástases ósseas são tratados com radiofármacos associados com quimioterapia para alívio da dor óssea. O objetivo do trabalho foi estudar a influência do docetaxel na biodistribuição do EDTMP-153-samário nos ossos e outros órgãos de ratos. MÉTODOS: Ratos Wistar foram aleatoriamente alocados em 2 grupos de 6 animais cada. O grupo DS (docetaxel/samário recebeu docetaxel (15 mg/kg intraperitoneal em dois ciclos com 11 dias de intervalo. Os ratos do grupo S (samário/controle não foram tratados com docetaxel. Nove dias após a quimioterapia, todos os animais receberam 0,1ml de EDTMP-153-samário via plexo orbital (25µCi. Após 2 horas, os animais foram mortos e feitas biópsias de cérebro, tireóide, pulmão, coração, estômago, cólon, fígado, rim e fêmures. O percentual de radioatividade por grama (%ATI/g de tecido de cada bi

  12. Marrow irradiation with high-dose 153Samarium-EDTMP followed by chemotherapy and hematopoietic stem cell infusion for acute myelogenous leukemia.

    Science.gov (United States)

    Rodriguez, Vilmarie; Anderson, Peter M; Litzow, Mark R; Erlandson, Linda; Trotz, Barbara A; Arndt, Carola A S; Khan, Shakila P; Wiseman, Gregory A

    2006-08-01

    In four patients, aged 15 - 20 years, with high-risk acute myeloid leukemia (AML), high-dose samarium 153-labelled ethylenediaminetetramethylenephosphonate (153Sm-EDTMP) was used for targeted marrow irradiation before preparative chemotherapy conditioning regimens and allogeneic (three patients) or autologous (one patient) hematopoietic stem cell transplantation. The dose of 153Sm-EDTMP was 703 MBq/kg (n = 1) or 1110 MBq/kg (n = 3). No side-effects occurred during the 30-min infusion of 153Sm-EDTMP. Samarium - melphalan regimens were given to three patients; one had 153Sm-EDTMP - busulfan + cyclophosphamide. Total body radioactivity was below the 133 MBq safe limit before infusion of stem cells (day 14 after 153Sm-EDTMP). No hemorrhagic cystitis, nephrotoxicity or serious infections occurred. Leukocyte engraftment (white blood cell count >0.5 x 10(9)/l) occurred between 12 and 23 days after stem cell infusion (mean of 17 days). Complete cytogenetic and morphologic remission of AML was evident on follow-up marrow aspirate and biopsy specimens from all patients. In two of the four study patients, the disease remains in complete remission and the patients have an excellent quality of life (Eastern Cooperative Oncology Group performance status 0; no medications) and no organ toxicity more than 2 years and more than 4 years, respectively, after their blood and bone marrow transplantations. Thus, in adolescents and adults, 153Sm-EDTMP may provide a relatively simple and effective means for using irradiation to eliminate AML within the marrow.

  13. Modification by H-termination in growth process of titanium silicide on Si(0 0 1)-2 x 1 observed with scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, T., E-mail: d08gd201@ynu.ac.jp [Faculty of Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501 (Japan); Shudo, K.; Sato, K.; Ohno, S.; Nishioka, H.; Iida, T.; Toramaru, M.; Tanaka, M. [Faculty of Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501 (Japan)

    2009-11-30

    Formation processes of titanium silicide on hydrogen-terminated H/Si(0 0 1)-2 x 1 surface are studied at the atomic scale with a scanning tunneling microscopy (STM). Square-shaped nanoislands were observed on the Ti/H/Si(0 0 1) surface after annealed at 873-1073 K. These are the epitaxial nanoislands moderately grown due to the local orientation relationship between C49-TiSi{sub 2} and Si(0 0 1), because passivation by surface hydrogen on Si(0 0 1) suppresses active and complex bond formation of Ti-Si.

  14. Effect of Chemistry and Particle Size on the Performance of Calcium Disilicide Primers. Part 1 - Synthesis of Calcium Silicide (CaSi2) by Rotary Atomization

    Science.gov (United States)

    2010-02-01

    reactions 1 and 2, respectively. A general rule of thumb for thermite reactions is that when the heat of formation per gram of product is lower than -1.6 kJ...34Calcium Silicide, CaSk" J. Chem. Soc Abstr. 82, II, 320, 1902. 2. Goldschmidt, H., "New Thermite Reactions, Iron Age, 82, 232, 1908. 3. MIL-C-324...Highway 361 Crane, IN 47522-5001 ATK Small Caliber System ATTN: M. Mansfield D. Clark R. Carpenter N. Tharp Lake City Army Ammunition Plant P.O. Box 1000 Independence, MO 64051-1000 16

  15. Effect of nickel silicide gettering on metal-induced crystallized polycrystalline-silicon thin-film transistors

    Science.gov (United States)

    Kim, Hyung Yoon; Seok, Ki Hwan; Chae, Hee Jae; Lee, Sol Kyu; Lee, Yong Hee; Joo, Seung Ki

    2017-06-01

    Low-temperature polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) fabricated via metal-induced crystallization (MIC) are attractive candidates for use in active-matrix flat-panel displays. However, these exhibit a large leakage current due to the nickel silicide being trapped at the grain boundaries of the poly-Si. We reduced the leakage current of the MIC poly-Si TFTs by developing a gettering method to remove the Ni impurities using a Si getter layer and natively-formed SiO2 as the etch stop interlayer. The Ni trap state density (Nt) in the MIC poly-Si film decreased after the Ni silicide gettering, and as a result, the leakage current of the MIC poly-Si TFTs decreased. Furthermore, the leakage current of MIC poly-Si TFTs gradually decreased with additional gettering. To explain the gettering effect on MIC poly-Si TFTs, we suggest an appropriate model. He received the B.S. degree in School of Advanced Materials Engineering from Kookmin University, Seoul, South Korea in 2012, and the M.S. degree in Department of Materials Science and Engineering from Seoul National University, Seoul, South Korea in 2014. He is currently pursuing the Ph.D. degree with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and top-gate polycrystalline-silicon thin-film transistors. He received the M.S. degree in innovation technology from Ecol Polytechnique, Palaiseau, France in 2013. He is currently pursuing the Ph.D. degree with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and bottom-gate polycrystalline-silicon thin-film transistors. He is currently pursuing the integrated M.S and Ph.D course with the Department of Materials Science and Engineering, Seoul National University, Seoul. He is involved in semiconductor device fabrication technology and copper

  16. Improvement of the thermal stability of nickel silicide using a ruthenium interlayer deposited via remote plasma atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Inhye [Department of Materials Science and Engineering, Hanyang University, Seoul 04763, South Korea and System LSI Manufacturing Operation Center, Samsung Electronics Co., Ltd, Gyeonggi-do 17113 (Korea, Republic of); Park, Jingyu; Jeon, Heeyoung; Kim, Hyunjung; Shin, Changhee [Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 04763 (Korea, Republic of); Shin, Seokyoon; Lee, Kunyoung [Department of Materials Science and Engineering, Hanyang University, Seoul 04763 (Korea, Republic of); Jeon, Hyeongtag, E-mail: hjeon@hanyang.ac.kr [Department of Materials Science and Engineering, Hanyang University, Seoul 04763, South Korea and Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 04763 (Korea, Republic of)

    2016-05-15

    In this study, the effects of a thin Ru interlayer on the thermal and morphological stability of NiSi have been investigated. Ru and Ni thin films were deposited sequentially to form a Ni/Ru/Si bilayered structure, without breaking the vacuum, by remote plasma atomic layer deposition (RPALD) on a p-type Si wafer. After annealing at various temperatures, the thermal stabilities of the Ni/Ru/Si and Ni/Si structures were investigated by various analysis techniques. The results showed that the sheet resistance of the Ni/Ru/Si sample was consistently lower compared to the Ni/Si sample over the entire temperature range. Although both samples exhibited the formation of NiSi{sub 2} phases at an annealing temperature of 800 °C, as seen with glancing angle x-ray diffraction, the peaks of the Ni/Ru/Si sample were observed to have much weaker intensities than those obtained for the Ni/Si sample. Moreover, the NiSi film with a Ru interlayer exhibited a better interface and improved surface morphologies compared to the NiSi film without a Ru interlayer. These results show that the phase transformation of NiSi to NiSi{sub 2} was retarded and that the smooth NiSi/Si interface was retained due to the activation energy increment for NiSi{sub 2} nucleation that is caused by adding a Ru interlayer. Hence, it can be said that the Ru interlayer deposited by RPALD can be used to control the phase transformation and physical properties of nickel silicide phases.

  17. Synthesis of samarium complexes with the derivative binder of Schiff Quinolinic base. Characterization and photophysical study; Sintesis de complejos de samario con el ligante derivado de base de Schiff Quinolinica. Caracterizacion y estudio fotofisico

    Energy Technology Data Exchange (ETDEWEB)

    Lucas H, J.

    2016-07-01

    In this work we determined the metal: binder stoichiometry of the species formed during the UV/Vis spectrophotometric titration of the derivative binder of Schiff quinolinic base, L1 with the samarium nitrate pentahydrate in methanol. Statistical analysis of the data allowed proposing the metal: binder stoichiometry for the synthesis of the complexes which was one mole of samarium salt by 2.5 moles of binder and thus favor the formation of complexes with 1M: 1L and 1M: 2L stoichiometries. They were synthesized in aqueous-organic medium (water-ethanol), isolated and purified two complexes with stoichiometry 1 Sm: 1 L1, complex 1 and 1 Sm: 2 L1, complex 2. The overall yield of the reaction was 76%. The characterization of the formed complexes was performed by visible ultraviolet spectrometry (UV/Vis), nuclear magnetic resonance, X-ray photoelectron spectroscopy (XP S), thermal gravimetric analysis with differential scanning calorimetry (TGA/DSC), and radial distribution function. These complexes were studied by fluorescence and emission phosphorescence at variable temperature. Spectroscopic techniques used in both solution and solid demonstrated the formation and stability of these complexes. In addition XP S indicated that in both complexes the samarium retains its oxidation state 3+. Luminescence studies indicated that there is intra-binding charge transfer which decreases the transfer of light energy from the binder to the samarium. Based on the experimental results, L1 binder molecules and complexes 1 and 2 were modeled that demonstrated the proposed Nc for each complex, as well as allowed to visualize the structural arrangement of the molecules, complexes and binder. (Author)

  18. Carrier-transport mechanism of Er-silicide Schottky contacts to strained-silicon-on-insulator and silicon-on-insulator.

    Science.gov (United States)

    Jyothi, I; Janardhanam, V; Kang, Min-Sung; Yun, Hyung-Joong; Lee, Jouhahn; Choi, Chel-Jong

    2014-11-01

    The current-voltage characteristics and the carrier-transport mechanism of the Er-silicide (ErSi1.7) Schottky contacts to strained-silicon-on-insulator (sSOI) and silicon-on-insulator (SOI) were investigated. Barrier heights of 0.74 eV and 0.82 eV were obtained for the sSOI and SOI structures, respectively. The barrier height of the sSOI structure was observed to be lower than that of the SoI structure despite the formation of a Schottky contact using the same metal silicide. The sSOI structure exhibited better rectification and higher current level than the SOI structure, which could be associated with a reduction in the band gap of Si caused by strain. The generation-recombination mechanism was found to be dominant in the forward bias for both structures. Carrier generation along with the Poole-Frenkel mechanism dominated the reverse-biased current in the SOI structure. The saturation tendency of the reverse leakage current in the sSOI structure could be attributed to strain-induced defects at the interface in non-lattice-matched structures.

  19. 45Sc Solid State NMR studies of the silicides Sc TSi ( T=Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt)

    Science.gov (United States)

    Harmening, Thomas; Eckert, Hellmut; Fehse, Constanze M.; Sebastian, C. Peter; Pöttgen, Rainer

    2011-12-01

    The silicides Sc TSi ( T=Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir, Pt) were synthesized by arc-melting and characterized by X-ray powder diffraction. The structures of ScCoSi, ScRuSi, ScPdSi, and ScIrSi were refined from single crystal diffractometer data. These silicides crystallize with the TiNiSi type, space group Pnma. No systematic influences of the 45Sc isotropic magnetic shift and nuclear electric quadrupolar coupling parameters on various structural distortion parameters calculated from the crystal structure data can be detected. 45Sc MAS-NMR data suggest systematic trends in the local electronic structure probed by the scandium atoms: both the electric field gradients and the isotropic magnetic shifts relative to a 0.2 M aqueous Sc(NO 3) 3 solution decrease with increasing valence electron concentration and within each T group the isotropic magnetic shift decreases monotonically with increasing atomic number. The 45Sc nuclear electric quadrupolar coupling constants are generally well reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code.

  20. Synthesis of nano-patterned and Nickel Silicide embedded amorphous Si thin layer by ion implantation for higher efficiency solar devices

    Science.gov (United States)

    Bhowmik, D.; Bhattacharjee, S.; Lavanyakumar, D.; Naik, V.; Satpati, B.; Karmakar, P.

    2017-11-01

    We report the ion beam based single step synthesis process of surface-patterned amorphous Silicon (a-Si) with a buried plasmon active nickel silicide layer for the realization of cost-effective, higher efficiency Silicon (Si) photovoltaic devices. Simultaneous amorphization, surface pattern formation and buried layer development are achieved by normal incidence 10 keV Ni1+ ion bombardment on Si(100) surface at a fluence of 1 × 1017. Atomic Force Microscopy study shows rim-surrounded crater like periodic nanostructure on the surface whereas cross-sectional Transmission Electron Microscopy detects the amorphization and implant buried layer just below the surface. The distribution of implanted Ni ions and Si vacancies, obtained by the Monte Carlo simulation (SRIM) is consistent with the experimental results. Spatially resolved Electron Energy Loss Spectroscopy measurement detects that the buried layer is nickel silicide. The potential application of such nano-patterned and plasmon active system for future low-cost a-Si based higher efficient Photovoltaic devices is discussed.

  1. Thermoelectric characteristics of iron silicide thermoelectric converter with the transition metallic compound as an additive; Sen`i kinzoku kagobutsu wo tenkabutsu to shita keikatetsu netsuden soshi no netsuden tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, M.; Oda, M. [Hitachi, Ltd., Tokyo (Japan)

    1994-04-13

    The thin film must be converted into a bulky shape in order that the high electric power may be produced by the iron silicide thermoelectric converter. Study was then made to establish the homogeneous bulk production method, in which the additive must diffuse sufficiently in the iron silicide and bond strongly to it during the sintering. Selected as an additive in the present study, Co compounds were all decomposed below the sintering temperature and remained in the iron silicide. The Co sulfide, phosphide, bromide and iodide were particularly high in reactivity with the iron silicide. The Co, of which the added quantity was proportional to the electric conductivity, was almost homogenized into a solid solution. In the experiment, both Co sulfide and phosphide were equal in thermoelectric power as an additive. The Co bromide and iodide were maximally about 10% and 50%, respectively lower in thermoelectric power than the Co sulfide. It is attributable to the FeSi2 reformed to the electrically insulating SiO2 and low-thermoelectric power FeSi, because both Co bromide and iodide are oxidizing compounds. 7 refs., 10 figs.

  2. Characterization of complex carbide–silicide precipitates in a Ni–Cr–Mo–Fe–Si alloy modified by welding

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyya, D., E-mail: dhb@ansto.gov.au; Davis, J.; Drew, M.; Harrison, R.P.; Edwards, L.

    2015-07-15

    Nickel based alloys of the type Hastelloy-N™ are ideal candidate materials for molten salt reactors, as well as for applications such as pressure vessels, due to their excellent resistance to creep, oxidation and corrosion. In this work, the authors have attempted to understand the effects of welding on the morphology, chemistry and crystal structure of the precipitates in the heat affected zone (HAZ) and the weld zone of a Ni–Cr–Mo–Fe–Si alloy similar to Hastelloy-N™ in composition, by using characterization techniques such as scanning and transmission electron microscopy. Two plates of a Ni–Cr–Mo–Fe–Si alloy GH-3535 were welded together using a TiG welding process without filler material to achieve a joint with a curved molten zone with dendritic structure. It is evident that the primary precipitates have melted in the HAZ and re-solidified in a eutectic-like morphology, with a chemistry and crystal structure only slightly different from the pre-existing precipitates, while the surrounding matrix grains remained unmelted, except for the zones immediately adjacent to the precipitates. In the molten zone, the primary precipitates were fully melted and dissolved in the matrix, and there was enrichment of Mo and Si in the dendrite boundaries after solidification, and re-precipitation of the complex carbides/silicides at some grain boundaries and triple points. The nature of the precipitates in the molten zone varied according to the local chemical composition. - Graphical abstract: Display Omitted - Highlights: • Ni-based alloy with Cr, Mo, Si, Fe and C was welded, examined with SEM, EBSD, and TEM. • Original Ni{sub 2}(Mo,Cr){sub 4}(Si,C) carbides changed from equiaxed to lamellar shape in HAZ. • Composition and crystal structure remained almost unchanged in HAZ. • Original carbides changed to lamellar Ni{sub 3}(Mo,Cr){sub 3}(Si,C) in some cases in weld metal. • Precipitates were mostly incoherent, but semi-coherent in some cases in weld

  3. Pyrolysis result of polyethylene waste as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-02-01

    In this research, the result of pyrolysis on polyethylene was used as fuel for a solid oxide fuel cell (SOFC). The pyrolysis result is a liquid which consists of hydrocarbon chains. According to GC-MS analysis, the hydrocarbons mainly consist of C7 to C20 hydrocarbon chain. Then, the liquid was applied to a single cell of NSDC-L | NSDC | NSDC-L. NSDC is a composite SDC (samarium doped-ceria) with sodium carbonate. Meanwhile, NSDC-L is a composite of NSDC with LiNiCuO (LNC). NSDC and LNC were analyzed by X-ray diffraction to understand their crystal structure. The result shows that presence of carbonate did not change the crystal structure of SDC. SEM EDX analysis for fuel cell before and after being loaded with polyethylene oil to get information of element diffusion to the electrolyte. Meanwhile, the conductivity properties were investigated through impedance measurement. The presence of carbonate even increases the electrical conductivity. The single cell test with the pyrolysis result of polyethylene at 300 - 600 °C, found that the highest power density is at 600 °C with the maximum power density of 0.14 mW/cm2 and open circuit voltage of 0.4 Volt. Elemental analysis at three point spots of single cell NDSC-L |NSDC|NSDC-L found that a migration of ions was occurred during fuel operation at 300 - 600 °C.

  4. Effects of some rare earth and carbonate-based co-dopants on structural and electrical properties of samarium doped ceria (SDC) electrolytes for solid oxide fuel cells

    Science.gov (United States)

    Anwar, Mustafa; Khan, Zuhair S.; Mustafa, Kamal; Rana, Akmal

    2015-09-01

    In the present study, samarium doped ceria (SDC) and SDC-based composite with the addition of K2CO3 were prepared by co-precipitation route and effects of pH of the solution and calcination temperature on microstructure of SDC and SDC-K2CO3, respectively, were investigated. Furthermore, experimentation was performed to investigate into the ionic conductivity of pure SDC by co-doping with yttrium i.e., YSDC, XRD and SEM studies show that the crystallite size and particle size of SDC increases with the increase in pH. The SEM images of all the samples of SDC synthesized at different pH values showed the irregular shaped and dispersed particles. SDC-K2CO3 was calcined at 600∘C, 700∘C and 800∘C for 4 h and XRD results showed that crystallite size increases while lattice strain, decreases with the increase in calcination temperature and no peaks were detected for K2CO3 as it is present in an amorphous form. The ionic conductivity of the electrolytes increases with the increase in temperature and SDC-K2CO3 shows the highest value of ionic conductivity as compared to SDC and YSDC. Chemical compatibility tests were performed between the co-doped electrolyte and lithiated NiO cathode at high temperature. It revealed that the couple could be used up to the temperature of 700∘C.

  5. Calculation of the Dose of Samarium-153-Ethylene Diamine Tetramethylene Phosphonate (153Sm-EDTMP as a Radiopharmaceutical for Pain Relief of bone Metastasis

    Directory of Open Access Journals (Sweden)

    Fatemeh Razghandi

    2016-04-01

    Full Text Available Introduction One of the important applications of nuclear physics in medicine is the use of radioactive elements as radiopharmaceuticals. Metastatic bone disease is the most common form of malignant bone tumors. Samarium-153-ethylene diamine tetramethylene phosphonate (153Sm-EDTMP as a radiopharmaceutical is used for pain palliation. This radiopharmaceutical usually emits beta particles, which have a high uptake in bone tissues. The purpose of this study was to calculate the radiation dose distribution of 153Sm-EDTMP in bone and other tissues, using MCNPX Monte Carlo code in the particle transport model. Materials and Methods Dose delivery to the bone was simulated by seeking radiopharmaceuticals on the bone surface. The phantom model had a simple cylindrical geometry and included bone, bone marrow, and soft tissue. Results The simulation results showed that a significant amount of radiation dose was delivered to the bone by the use of this radiopharmaceutical. Conclusion Thebone acted as a fine protective shield against rays for the bone marrow. Therefore, the trivial absorbed dose by the bone marrow caused less damage to bone-making cells. Also, the high absorbed dose of the bone could destroy cancer cells and relieve the pain in the bone.

  6. Synthesis, quality control and biological evaluation of tris[(1,10-phenanthroline)[{sup 153}Sm]samarium(III)]trithiocyanate complex as a therapeutic agent

    Energy Technology Data Exchange (ETDEWEB)

    Naseri, Z.; Kharat, A. Nemati [Tehran Univ. (Iran, Islamic Republic of). Inorganic Chemistry Dept.; Hakimi, A. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Nuclear Engineering, Science and Research Branch; Jalilian, A.R.; Shirvani-Arani, S.; Bahrami-Samani, A.; Ghannadi-Maragheh, M. [Nuclear Science and Technology Research Institute (NSTRI), Tehran (IR). Radiopharmaceutical Research and Development Lab (RRDL)

    2012-07-01

    Therapeutic radiopharmaceuticals are designed to deliver high doses of radiation to selected target organs or tissues with an aim of minimizing unwanted radiation to surrounding healthy tissue. In this work, [tris(1,10-phenanthroline)[{sup 153}Sm]samarium(III)]trithiocyanate ({sup 153}Sm-TPTTC) was developed for possible therapeutic properties. The cold compound, i.e. {sup nat}Sm-TPTTC was prepared and characterized by IR, UV, mass and {sup 1}H-NMR spectroscopy. {sup 153}Sm-TPTTC was prepared in two steps using [{sup 153}Sm]SmCl{sub 3}, obtained by neutron activation of an enriched {sup 152}Sm sample. Stability tests, partition coefficient determination, toxicity tests and biodistribution studies of the complex in wild-type and fibrosarcoma-bearing mice were determined. The radiolabeled complex was prepared in high radiochemical purity (> 99% precipitation method) and specific activity of 278 GBq/mmol and demonstrated significant stability at 4, 25 and 37 C (in presence of human serum). Initial complex biodistribution data showed significant liver accumulation in wild-type mice and significant tumor accumulation in fibrosarcoma-bearing mice with tumor:blood and tumor:muscle ratios of 3.55 (2 h) and 38.26 (96 h) respectively. {sup 153}Sm-TPTTC properties suggest an efficient tumor targeting agent with high tumor-avidity. Further investigation on the therapeutic properties must be conducted. (orig.)

  7. Safety evaluation report related to the evaluation of low-enriched uranium silicide-aluminum dispersion fuel for use in non-power reactors

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    Low-enriched uranium silicide-aluminum dispersion plate-type fuels have been extensively researched and developed under the international program, Reduced Enrichment in Research and Test Reactors. The international effort was led by Argonne National Laboratory (ANL) in the United States. This evaluation is based primarily on reports issued by ANL that discuss and summarize the developmental tests and experiments, including postirradiation examinations, of both miniature and full-sized plates of prototypical fuel compositions. This evaluation concludes that plate-type fuels suitable and acceptable for use in research and test reactors can be fabricated with U/sub 3/Si/sub 2/-Al dispersion compacts with uranium densities up to 4.8 g/cm/sup 3/. 4 refs., 1 fig.

  8. Silicides for VLSI applications

    CERN Document Server

    Murarka, Shyam P

    1983-01-01

    Most of the subject matter of this book has previously been available only in the form of research papers and review articles. I have not attempted to refer to all the published papers. The reader may find it advantageous to refer to the references listed.

  9. Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues; Capacidad de retencion de samario (III) en circon para su posible uso en barreras de contencion para confinamiento de residuos nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Garcia G, N

    2006-07-01

    Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH{sub PCN}) and density of surface sites (D{sub s}). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

  10. SU-C-201-06: Utility of Quantitative 3D SPECT/CT Imaging in Patient Specific Internal Dosimetry of 153-Samarium with GATE Monte Carlo Package

    Energy Technology Data Exchange (ETDEWEB)

    Fallahpoor, M; Abbasi, M [Tehran University of Medical Sciences, Vali-Asr Hospital, Tehran, Tehran (Iran, Islamic Republic of); Sen, A [University of Houston, Houston, TX (United States); Parach, A [Shahid Sadoughi University of Medical Sciences, Yazd, Yazd (Iran, Islamic Republic of); Kalantari, F [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: Patient-specific 3-dimensional (3D) internal dosimetry in targeted radionuclide therapy is essential for efficient treatment. Two major steps to achieve reliable results are: 1) generating quantitative 3D images of radionuclide distribution and attenuation coefficients and 2) using a reliable method for dose calculation based on activity and attenuation map. In this research, internal dosimetry for 153-Samarium (153-Sm) was done by SPECT-CT images coupled GATE Monte Carlo package for internal dosimetry. Methods: A 50 years old woman with bone metastases from breast cancer was prescribed 153-Sm treatment (Gamma: 103keV and beta: 0.81MeV). A SPECT/CT scan was performed with the Siemens Simbia-T scanner. SPECT and CT images were registered using default registration software. SPECT quantification was achieved by compensating for all image degrading factors including body attenuation, Compton scattering and collimator-detector response (CDR). Triple energy window method was used to estimate and eliminate the scattered photons. Iterative ordered-subsets expectation maximization (OSEM) with correction for attenuation and distance-dependent CDR was used for image reconstruction. Bilinear energy mapping is used to convert Hounsfield units in CT image to attenuation map. Organ borders were defined by the itk-SNAP toolkit segmentation on CT image. GATE was then used for internal dose calculation. The Specific Absorbed Fractions (SAFs) and S-values were reported as MIRD schema. Results: The results showed that the largest SAFs and S-values are in osseous organs as expected. S-value for lung is the highest after spine that can be important in 153-Sm therapy. Conclusion: We presented the utility of SPECT-CT images and Monte Carlo for patient-specific dosimetry as a reliable and accurate method. It has several advantages over template-based methods or simplified dose estimation methods. With advent of high speed computers, Monte Carlo can be used for treatment planning

  11. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO2) thin films using electron beam evaporation

    Science.gov (United States)

    Kundu, Subrata; Sutradhar, Narottam; Thangamuthu, R.; Subramanian, B.; Panda, Asit Baran; Jayachandran, M.

    2012-08-01

    Samarium (Sm)-doped cerium oxide (CeO2) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV-Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature ( 300 or 500 °C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV-Vis, XPS, and XRD analyses. The FT-IR study proves the presence of -COO-, -OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO2 nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO2 nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH4. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO2 thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.

  12. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO{sub 2}) thin films using electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Subrata, E-mail: skundu@cecri.res.in [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India); Sutradhar, Narottam [G. B. Marg, Central Salt and Marine Chemical Research Institute - CSIR (India); Thangamuthu, R.; Subramanian, B. [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India); Panda, Asit Baran [G. B. Marg, Central Salt and Marine Chemical Research Institute (CSIR) (India); Jayachandran, M., E-mail: mjayam54@yahoo.com [Council of Scientific and Industrial Research (CSIR), Electrochemical Materials Science (ECMS) Division, Central Electrochemical Research Institute - CECRI (India)

    2012-08-15

    Samarium (Sm)-doped cerium oxide (CeO{sub 2}) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV-Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature ({approx}300 or 500 Degree-Sign C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV-Vis, XPS, and XRD analyses. The FT-IR study proves the presence of -COO-, -OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO{sub 2} nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO{sub 2} nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH{sub 4}. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO{sub 2} thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.Graphical Abstract.

  13. Crystal structure of monoclinic samarium and cubic europium sesquioxides and bound coherent neutron scattering lengths of the isotopes {sup 154}Sm and {sup 153}Eu

    Energy Technology Data Exchange (ETDEWEB)

    Kohlmann, Holger [Leipzig Univ. (Germany). Inst. of Inorganic Chemistry; Hein, Christina; Kautenburger, Ralf [Saarland Univ., Saarbruecken (Germany). Inorganic Solid State Chemistry; Hansen, Thomas C.; Ritter, Clemens [Institut Laue-Langevin, Grenoble (France); Doyle, Stephen [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Synchrotron Radiation (ISS)

    2016-11-01

    The crystal structures of monoclinic samarium and cubic europium sesquioxide, Sm{sub 2}O{sub 3} and Eu{sub 2}O{sub 3}, were reinvestigated by powder diffraction methods (laboratory X-ray, synchrotron, neutron). Rietveld analysis yields more precise structural parameters than previously known, especially for oxygen atoms. Interatomic distances d(Sm-O) in Sm{sub 2}O{sub 3} range from 226.3(4) to 275.9(2) pm [average 241.6(3) pm] for the monoclinic B type Sm{sub 2}O{sub 3} [space group C2/m, a = 1418.04(3) pm, b = 362.660(7) pm, c = 885.48(2) pm, β = 100.028(1) ], d(Eu-O) in Eu{sub 2}O{sub 3} from 229.9(2) to 238.8(2) pm for the cubic bixbyite (C) type [space group Ia anti 3, a = 1086.87(1) pm]. Neutron diffraction at 50 K and 2 K did not show any sign for magnetic ordering in Sm{sub 2}O{sub 3}. Isotopically enriched {sup 154}Sm{sub 2}O{sub 3} and {sup 153}Eu{sub 2}O{sub 3} were used for the neutron diffraction work because of the enormous absorption cross section of the natural isotopic mixtures for thermal neutrons. The isotopic purity was determined by inductively coupled plasma - mass spectrometry to be 98.9% for {sup 154}Sm and 99.8% for {sup 153}Eu. Advanced analysis of the neutron diffraction data suggest that the bound coherent scattering lengths of {sup 154}Sm and {sup 153}Eu need to be revised. We tentatively propose b{sub c}({sup 154}Sm) = 8.97(6) fm and b{sub c}({sup 153}Eu) = 8.85(3) fm for a neutron wavelength of 186.6 pm to be better values for these isotopes, showing up to 8% deviation from accepted literature values. It is shown that inaccurate scattering lengths may result in severe problems in crystal structure refinements causing erroneous structural details such as occupation parameters, which might be critically linked to physical properties like superconductivity in multinary oxides.

  14. Synthesis, Characterization, and Mechanism of Formation of Janus-Like Nanoparticles of Tantalum Silicide-Silicon (TaSi2/Si

    Directory of Open Access Journals (Sweden)

    Andrey V. Nomoev

    2014-12-01

    Full Text Available Metal-semiconductor Janus-like nanoparticles with the composition tantalum silicide-silicon (TaSi2/Si were synthesized for the first time by means of an evaporation method utilizing a high-power electron beam. The composition of the synthesized particles were characterized using high-resolution transmission electron microscopy (HRTEM, X-ray diffraction (XRD, selective area electron diffraction (SAED, and energy dispersive X-ray fluorescence (EDX analysis. The system is compared to previously synthesized core-shell type particles in order to show possible differences responsible for the Janus-like structure forming instead of a core-shell architecture. It is proposed that the production of Janus-like as opposed to core-shell or monophase particles occurs due to the ability of Ta and Si to form compounds and the relative content of Ta and Si atoms in the produced vapour. Based on the results, a potential mechanism of formation for the TaSi2/Si nanoparticles is discussed.

  15. Low Contact Resistivity with Low Silicide/p+-Silicon Schottky Barrier for High-Performance p-Channel Metal-Oxide-Silicon Field Effect Transistors

    Science.gov (United States)

    Tanaka, Hiroaki; Isogai, Tatsunori; Goto, Tetsuya; Teramoto, Akinobu; Sugawa, Shigetoshi; Ohmi, Tadahiro

    2010-04-01

    A current drivability improvement of p-channel metal-oxide-silicon field effect transistors (MOSFETs) is necessary for the performance enhancement of complementary metal-oxide-semiconductor (CMOS) circuits. In this paper, we present the key technology for fabricating indispensable CMOS circuits with a small Schottky barrier height and a low contact resistance for p-type silicon using Pd2Si. We fabricated a Pd2Si gate Schottky barrier diode and a Kelvin pattern on silicon. The measured Schottky barrier height is 0.29 eV for p-type silicon. We also realized a very low contact resistivity of 3.7 ×10-9 Ω cm2 for the p+ region of silicon. The p-channel MOSFET with Pd2Si source/drain contacts realized a good characteristic, that is, a small off current. The technology developed in this work involves silicide formation for source/drain contacts of p-channel MOSFETs, which is expected to realize the performance enhancement of MOSFETs.

  16. Highly CO2-Tolerant Cathode for Intermediate-Temperature Solid Oxide Fuel Cells: Samarium-Doped Ceria-Protected SrCo0.85Ta0.15O3-δ Hybrid.

    Science.gov (United States)

    Li, Mengran; Zhou, Wei; Zhu, Zhonghua

    2017-01-25

    Susceptibility to CO2 is one of the major challenges for the long-term stability of the alkaline-earth-containing cathodes for intermediate-temperature solid oxide fuel cells. To alleviate the adverse effects from CO2, we incorporated samarium-stabilized ceria (SDC) into a SrCo0.85Ta0.15O3-δ (SCT15) cathode by either mechanical mixing or a wet impregnation method and evaluated their cathode performance stability in the presence of a gas mixture of 10% CO2, 21% O2, and 69% N2. We observed that the CO2 tolerance of the hybrid cathode outperforms the pure SCT15 cathode by over 5 times at 550 °C. This significant enhancement is likely attributable to the low CO2 adsorption and reactivity of the SDC protective layer, which are demonstrated through thermogravimetric analysis, energy-dispersive spectroscopy, and electrical conductivity study.

  17. M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhihong [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti5Si3-based alloys was investigated. Oxidation behavior of Ti5Si3-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti5Si3 by nucleation and growth of nitride subscale. Ti5Si3.2and Ti5Si3C0.5 alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi2 coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo3Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo3Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nbss (solid solution) and NbB are the only two primary phases in the 0-40 at.% B composition range, and the eutectic reaction L {leftrightarrow} NbSS + NbB was determined to occur at 2104 ± 5 C by DTA.

  18. Ferrites Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} doped with samarium: structural analysis, morphological and electromagnetic; Ferritas Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 4} dopada com samario: analise estrutural, morfologica e eletromagnetica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A.C.F.M.; Diniz, A.P., E-mail: anacristina@dema.ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academinca de Engenharia de Materiais; Viana, K.M.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, PE (Brazil). Escola de Ciencias e Tecnologia; Cornejo, D.R. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2010-07-01

    This paper proposes to investigate the sintering at 1200 deg C/2h of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2-x}Sm{sub x}O{sub 4} ferrite doped with 0.05; 0.075 e 0.1 mol of Sm synthesized by combustion reaction to evaluate the performance materials as absorbers of electromagnetic radiation. The influence of the concentration of samarium on the structure, morphology and electromagnetic properties of ferrites was studied. The resulting samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), magnetic measurements and reflectivity measurements in the frequency range between 8-12 GHz. The results showed that increasing the concentration of samarium caused a decrease in particle size of the samples, encouraging, therefore, to obtain materials with better values of magnetization and reflectivity, allowing for use as absorbers in narrow-band frequency between 9-10 GHz. (author)

  19. Accelerations of {epsilon}+{alpha}{yields}{beta} transformation and sintering of iron silicide by addition of Pd; Pd tenka ni yoru keikatetsu no {epsilon}+{alpha}{yields}{beta} hentai to shoketsu no sokushin

    Energy Technology Data Exchange (ETDEWEB)

    Kato, M.; Yamamoto, N.; Takeda, T. [Isuzu Advanced Engineering Center Ltd., Kanagawa (Japan); Hayashi, K. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science

    1996-12-15

    FeSi2 ({beta} phase) semiconducting iron silicide, which is expected to be widely used as a thermoelectric material in high temperature environment, is formed below 1259K by the peritectoid reaction of FeSi ({epsilon}) and Fe2Si5 ({alpha}) two metallic phases. Because the transformation of {epsilon} + {alpha} {yields} {beta} caused by this peritectoid reaction occurs considerably slowly, the iron silicide material which is produced by sintering of the powder at temperatures above 1259K has to be isothermally heat-treated for at least 180ks at about 1120K after the sintering so that the transformation occurs completely. We have found that the transformation was drastically accelerated by the addition of a small amount of Pd in the same way as Cu; the isothermal heat-treatment time necessary for the completion of the transformation was reduced to about 1/60. The sintering time needed for the almost full densification of the powder by pressure DCL sintering (DCL; direct current loading) was also reduced. A hypothesis for the mechanisms was proposed. 15 refs., 7 figs., 2 tabs.

  20. Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires; Aufbau einer Vierspitzen-Rastertunnelmikroskop/Rasterelektronenmikroskop-Kombination und Leitfaehigkeitsmessungen an Silizid Nanodraehten

    Energy Technology Data Exchange (ETDEWEB)

    Zubkov, Evgeniy

    2013-09-01

    In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

  1. Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy Avaliação retrospectiva do tratamento da dor óssea metastática com Samário-153-EDTMP

    Directory of Open Access Journals (Sweden)

    Marcelo Tatit Sapienza

    2004-01-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the degree of metastatic bone pain palliation and medullar toxicity associated with samarium-153-EDTMP treatment. METHODS: Seventy-three patients with metastatic bone pain having previously undergone therapy with samarium-153-EDTMP (1 mCi/kg were retrospectively evaluated. Routine follow-up included pain evaluation and blood counts for 2 months after treatment. Pain was evaluated using a subjective scale (from 0 to 10 before and for 8 weeks after the treatment. Blood counts were obtained before treatment and once a week for 2 months during follow-up. Dosimetry, based upon the urinary excretion of the isotope, was estimated in 41 individuals, and the resulting radiation absorbed doses were correlated with hematological data. RESULTS: Reduction in pain scores of 75% to 100% was obtained in 36 patients (49%, with a decrease of 50% to 75%, 25% to 50%, and 0% to 25% in, respectively, 20 (27%, 10 (14%, and 7 (10% patients. There was no significant relationship between the pain response and location of the primary tumor (breast or prostate cancer. Mild to moderate myelosuppression was noted in 75.3% of patients, usually with hematological recovery at 8 weeks. The mean bone marrow dose was 347 ± 65 cGy, and only a weak correlation was found between absorbed dose and myelosuppression (Pearson coefficient = .4. CONCLUSIONS: Samarium-153-EDTMP is a valuable method for metastatic bone pain palliation. A mild to moderate and transitory myelosuppression is the main toxicity observed after samarium therapy, showing a weak correlation with dosimetric measures.OBJETIVO: O presente trabalho teve por objetivo avaliar o efeito paliativo da dor e a toxicidade medular associados ao tratamento com Samário-153-EDTMP em pacientes com metástases ósseas. MÉTODOS: O estudo foi realizado de forma retrospectiva, a partir do levantamento de prontuário de 178 pacientes submetidos a tratamento com 1mCi/kg de 153Sm

  2. The dynamics of the laser-induced metal-semiconductor phase transition of samarium sulfide (SmS); Die Dynamik des laserinduzierten Metall-Halbleiter-Phasenuebergangs von Samariumsulfid (SmS)

    Energy Technology Data Exchange (ETDEWEB)

    Kaempfer, Tino

    2009-12-15

    The present thesis is dedicated to the experimental study of the metal-semiconductor phase transition of samarium sulfide (SmS): Temperature- and time-resolved experiments on the characterization of the phase transition of mixed-valence SmS samples (M-SmS) are presented. The measurement of the dynamics of the laser-induced phase transition pursues via time-resolved ultrashort-time microscopy and by X-ray diffraction with sub-picosecond time resolution. The electronic and structural processes, which follow an excitation of M-SmS with infrared femtosecond laser pulses, are physically interpreted on the base of the results obtained in this thesis and model imaginations. [German] Die vorliegende Arbeit ist der experimentellen Untersuchung des Metall-Halbleiter-Phasenuebergangs von Samariumsulfid (SmS) gewidmet. Es werden temperatur- und zeitaufgeloeste Experimente zur Charakterisierung des Phasenuebergangs gemischt-valenter SmS Proben (M-SmS) vorgestellt. Die Messung der Dynamik des laserinduzierten Phasenuebergangs erfolgt ueber zeitaufgeloeste Ultrakurzzeit-Mikroskopie und durch Roentgenbeugung mit subpikosekunden Zeitaufloesung. Die elektronischen und strukturellen Prozesse, welche einer Anregung von M-SmS mit infraroten Femtosekunden-Laserpulsen folgen, werden auf der Basis der in dieser Arbeit gewonnenen Ergebnisse und Modellvorstellungen physikalisch interpretiert. (orig.)

  3. Studies of valence of selected rare earth silicides determined using Si K and Pd/Rh L{sub 2,3} XANES and LAPW numerical studies

    Energy Technology Data Exchange (ETDEWEB)

    Zajdel, P., E-mail: pawel.zajdel@us.edu.pl [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Kisiel, A., E-mail: andrzej.kisiel@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Kraków (Poland); Szytuła, A., E-mail: andrzej.szytula@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Kraków (Poland); Goraus, J., E-mail: jerzy.goraus@us.edu.pl [Institute of Physics, University of Silesia, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Balerna, A., E-mail: antonella.balerna@lnf.infn.it [Laboratori Nazionali di Frascati, INFN, Lab DAPHINE-Light, Via E. Fermi 40, I-00044 Frascati (Italy); Banaś, A., E-mail: slsba@nus.edu.sg [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Starowicz, P., E-mail: pawel.starowicz@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Kraków (Poland); Konior, J., E-mail: jerzy.konior@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Kraków (Poland); Cinque, G., E-mail: gianfelice.cinque@diamond.ac.uk [Diamond Light Source, Harwell Campus, OX11 0DE Chilton-Didcot (United Kingdom); Grilli, A., E-mail: antonio.grilli@lnf.infn.it [Laboratori Nazionali di Frascati, INFN, Lab DAPHINE-Light, Via E. Fermi 40, I-00044 Frascati (Italy)

    2015-12-01

    Highlights: • The Si K and Pd L{sub 3} edges of R{sub 2}PdSi{sub 3} (R = Ce, Nd, Tb, Dy, Ho, Er) and HoRh{sub 2−x}Pd{sub x}Si{sub 2} are reported. • The R–Si bonds possess polar and 4d5s bands of Pd and Rh metallic characters. • There is no indication of Ce having a different valence than the other rare earths. • The positions and features of the calculated edges exhibit a fair agreement up to ≈10 eV. • The supercell used for Ho{sub 2}PdSi{sub 3} is good enough to reproduce the Si K edge. - Abstract: We report on the investigation of Si and Pd/Rh chemical environments using X-ray Absorption Near Edge Spectroscopy in two different families of rare earth silicides R{sub 2}PdSi{sub 3} (R = Ce, Nd, Tb, Dy, Ho, Er) and HoRh{sub 2−x}Pd{sub x}Si{sub 2} (x = 0, 0.5, 0.75, 1.0, 1.5, 1.8, 2.0). The Si K, Pd L{sub 3} and Rh L{sub 3} absorption edges were recorded in order to follow their changes upon the variation of 4f and 4d5s electron numbers. In both cases it was found that the Si K edge was shifted ≈0.5 eV toward lower energies, relative to pure silicon. In the first family, the shift decreases with increasing number of f-electrons, while the Si K edge remains constant upon rhodium–palladium substitution. In all cases the Pd L{sub 3} edge was shifted to higher energies relative to metallic Pd. No visible change in the Pd L{sub 3} position was observed either with a varying 4f electron count or upon Pd/Rh substitution. Also, the Rh L{sub 3} edge did not change. For two selected members, Ho{sub 2}PdSi{sub 3} and HoPd{sub 2}Si{sub 2}, the Wien2K’09 (LDA + U) package was used to calculate the electronic structure and the absorption edges. Si K edges were reproduced well for both compounds, while Pd L{sub 3} only exhibited a fair agreement for the second compound. This discrepancy between the Pd L{sub 3} theory and experiment for the Ho{sub 2}PdSi{sub 3} sample can be attributed to the specific ordered superstructure used in the numerical calculations

  4. Metal silicides with energetic pulses

    Science.gov (United States)

    D'Anna, E.; Leggieri, G.; Luches, A.; Majni, G.; Nava, F.; Ottaviani, G.

    1986-07-01

    Samples formed of a thin metal film deposited on silicon single crystal were annealed with electron and laser (ruby and excimer) pulses over a wide range of fluences. From a comparison of the experimental results with the temperature profiles of the irradiated samples, it turns out that suicide formation starts when the metal/silicon interface reaches the lowest eutectic temperature of the binary metal/silicon system. The growth rate of reacted layers is of the order of 1 m/s.

  5. Ternary silicides ScIr{sub 4}Si{sub 2} and RERh{sub 4}Si{sub 2} (RE = Sc, Y, Tb-Lu) and quaternary derivatives RERh{sub 4}Si{sub 2-x}Sn{sub x} (RE = Y, Nd, Sm, Gd-Lu) - structure, chemical bonding, and solid state NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vosswinkel, Daniel; Benndorf, Christopher; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos (Brazil). Inst. of Physics; Matar, Samir F. [Bordeaux Univ., CNRS, ICMCB, UPR 9048, Pessac (France)

    2016-11-01

    The silicides ScIr{sub 4}Si{sub 2} and RERh{sub 4}Si{sub 2} (RE = Sc, Y, Tb-Lu) and silicide stannides RERh{sub 4}Si{sub 2-x}Sn{sub x}(RE = Y, Nd, Sm, Gd-Lu) were synthesized from the elements by arc-melting and subsequent annealing. The new compounds crystallize with the orthorhombic YRh{sub 4}Ge{sub 2} type structure, space group Pnma. They were characterized by X-ray powder patterns and several structures were refined from single crystal X-ray diffractometer data. The main structural motifs of this series of silicides are tricapped trigonal prisms formed by the transition metal and rare earth atoms. One of the two crystallographically independent silicon sites allows for formation of solid solutions with tin, exemplarily studied for ErRh{sub 4}Si{sub 2-x}Sn{sub x}. Electronic structure calculations reveal strong covalent Rh-Si bonding as the main stability factor. Multinuclear ({sup 29}Si, {sup 45}Sc, and {sup 89}Y) magic-angle spinning (MAS) NMR spectra of the structure representatives with diamagnetic rare-earth elements (Sc, Y, Lu) are found to be consistent with the crystallographic data and specifically confirm the selective substitution of Sn in the Si2 sites in the quaternary compounds YRh{sub 4}SiSn and LuRh{sub 4}SiSn.

  6. A NOVEL SAMARIUM COMPLEX WITH INTERESTING ...

    African Journals Online (AJOL)

    INTRODUCTION. Fluorescent materials, particularly blue fluorescent materials have gained strong interest because ... emitting complexes in different technical applications, such as emitting materials for organic light emitting ..... properties of three novel two-dimensional lanthanide coordination polymers with mixed aromatic ...

  7. Pyroelectric Ferroelectric and Resistivity Studies on Samarium ...

    African Journals Online (AJOL)

    Barium Strontium Sodium Niobate (Ba1-xSrx)2NaNb5O15 (BSNN) belongs to tungsten bronze ferroelectric morphotrophic phase boundary (MPB) system at x = 0.6, having large spontaneous polarisation, pyroelectric coefficient and low dielectic constant and is expected to be applicable for piezoceramic filter and ...

  8. A NOVEL SAMARIUM COMPLEX WITH INTERESTING ...

    African Journals Online (AJOL)

    emitting complexes in different technical applications, such as emitting materials for organic light emitting diodes, sensitizers in solar energy conversion, chemical sensors and so forth [6-9]. The ability of bipy to act as a rigid ..... properties of three-dimensional organic-inorganic hybrids based on α-metatungstate. Inorg. Chim.

  9. Dual fuel gradients in uranium silicide plates

    Energy Technology Data Exchange (ETDEWEB)

    Pace, B.W. [Babock and Wilcox, Lynchburg, VA (United States)

    1997-08-01

    Babcock & Wilcox has been able to achieve dual gradient plates with good repeatability in small lots of U{sub 3}Si{sub 2} plates. Improvements in homogeneity and other processing parameters and techniques have allowed the development of contoured fuel within the cladding. The most difficult obstacles to overcome have been the ability to evaluate the bidirectional fuel loadings in comparison to the perfect loading model and the different methods of instilling the gradients in the early compact stage. The overriding conclusion is that to control the contour of the fuel, a known relationship between the compact, the frames and final core gradient must exist. Therefore, further development in the creation and control of dual gradients in fuel plates will involve arriving at a plausible gradient requirement and building the correct model between the compact configuration and the final contoured loading requirements.

  10. Determination of specific radioactivity of samarium-153 product. 1. Quantitative determination of samarium by spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumo, Mishiroku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nemoto, Masahiro [Tokyo Nuclear Service Co., Ltd., Tokyo (Japan)

    2002-03-01

    On the specific radioactivity of Sm-153 for the radiotherapy of cancers, a simple method for determination of the amount of Sm was described. The method used Arsenazo III as a colorimetric reagent. The sample irradiated in the reactor was dissolved in 1M HCl solution. A small part of it was taken and mixed with Arsenazo III at pH 3.2, and the amount of Sm was determined by the spectrophotometric method at a wavelength of 652 nm. The molar absorptivity of Sm at 652 nm was 6.6x10{sup 3} m{sup -1}{center_dot}mm{sup -1}. The error of measurement in the partial different conditions was about 2% of the value determined. The effects of impurities, Fe, Zn and Cu mixing in the Sm during operation, were clarified. (author)

  11. The growth and reactivity of the {Sm}/{Si(100)} interface

    Science.gov (United States)

    Onsgaard, J.; Christiansen, M.; Ørskov, F.; Godowski, P. J.

    1991-05-01

    The growth of the {Sm}/{Si(100)} interface is described and discussed in the context of the increasing experimental insight into lanthanide/semiconductor interfaces. Silicide formation takes place in the 1 to 5 monolayers coverage region. Different ordered structures, dependent on the initial coverage and temperature treatment, are observed. Oxygen adsorption and binding is strongly promoted, both when Sm is present at the surface and when oxygen reacts with a samarium-suicide film.

  12. Radiolesão vascular como efeito deletério da braquiterapia intra-arterial com dose elevada de Samário-153 em coelhos hipercolesterolêmicos Vascular radiolesion as a deleterious effect of high-dose-rate intraarterial brachytherapy with Samarium-153 in hypercholesterolemic rabbits

    Directory of Open Access Journals (Sweden)

    Dalton Bertolim Précoma

    2006-10-01

    Full Text Available OBJETIVO: Este estudo tem por objetivo avaliar as alterações vasculares morfológicas e morfométricas induzidas pela braquiterapia com Samário-153 (153 Sm em coelhos hipercolesterolêmicos, com doses elevadas. MÉTODOS: Foram analisados 43 coelhos hipercolesterolêmicos, brancos, da raça New Zealand, e o total de 86 artérias ilíacas submetidas a lesão por balão de angioplastia. Divididos em três grupos: dois (GI irradiados com as doses de 15Gy (n=14 e 60Gy (n=36 e um grupo controle (n=36. Foram realizadas avaliação histológica morfométrica e análise histológica qualitativa para análise tecidual. RESULTADOS: Foram observadas uma redução significativa da neoproliferação intimal (NPI no GI 15 Gy (pOBJECTIVE: This study was designed to evaluate vascular morphological and morphometric changes induced by brachytherapy with samarium-153 (Sm-153 at high doses in hypercholesterolemic rabbits. METHODS: Forty-three New Zealand White hypercholesterolemic rabbits were analyzed, and the total of 86 iliac arteries underwent balloon angioplasty injury. The rabbits were divided into three different groups: two irradiation groups (IG assigned to 15 Gy (n=14 and 60 Gy (n=36 irradiation doses, respectively, and a control group (n = 36. Histomorphometric and qualitative histological analyses were performed for tissue evaluation. RESULTS: Significant reductions were found in neointimal proliferation (NIP (p< 0.0001, media area (MA (p<0.0001 and percent stenosis (p<0.0001 in the 15-Gy IG, compared to the other groups. The 60-Gy IG had the higher rate of NIP, increase in media and vessel areas (VA and percent stenosis. The 60-Gy IG also showed the greatest number of xanthomatous cells (60-Gy IG: 86.11% and 15-Gy IG: 14.29%, p<0.0001 and the highest amount of hyaline amorphous tissue (60-Gy IG:58.33% and 15-Gy IG:0%, p=0.0001 and vascular proliferation (60-Gy IG:30.56% and 15-Gy IG:0%, p=0.0221. No statistically significant differences were found

  13. Optical characteristics of transparent samarium oxide thin films ...

    Indian Academy of Sciences (India)

    2016-10-07

    Oct 7, 2016 ... 1Department of Physics, Faculty of Science, Taif University, Taif 888, Saudi Arabia. 2Department of Physics, Faculty of Education, Ain Shams University, Roxy 11757, Cairo, Egypt. 3Materials Science Unit, Department of Chemistry, Faculty of Science, Tanta University, 31725 Tanta, Egypt. 4Department of ...

  14. Optical properties of lead–tellurite glasses doped with samarium ...

    Indian Academy of Sciences (India)

    The optical properties of a new family of Sm2O3–(40–)PbO–60TeO2 glasses are investigated. The optical absorption spectra were recorded at ... The refractive index, molar refraction and polarizability of oxide ions have been calculated by using Lorentz–Lorentz relations. The non-linear variations of the above optical ...

  15. Optical properties of lead–tellurite glasses doped with samarium ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The optical properties of a new family of xSm2O3–(40–x)PbO–60TeO2 glasses are investigated. The optical absorption spectra were recorded at room temperature in the UV-visible region. From the absorption edge studies, the values of optical bandgap energies have been evaluated. The refractive index, molar ...

  16. Measurement of radiative lifetime in atomic samarium using ...

    Indian Academy of Sciences (India)

    2014-02-08

    Feb 8, 2014 ... In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm. −1 .... introduced by an electronic delay generator between the two Q-switch pulses of Nd-YAG laser. The slope of the .... Our values of the lifetimes are free from the common systematic errors. Thus ...

  17. A novel samarium complex with interesting photoluminescence and ...

    African Journals Online (AJOL)

    The 4,4'-Hbipy moieties, isolated nitrates and [Sm(H2O)4(NO3)3] species are held together via hydrogen bonds and p…p interactions to form a 3-D supramolecular framework. Luminescent investigation reveals a strong emission in blue region. Optical absorption spectrum of 1 reveals the presence of an optical gap of 3.60 ...

  18. Lithium samarium polyphosphate, LiSm(PO34

    Directory of Open Access Journals (Sweden)

    Dan Zhao

    2010-02-01

    Full Text Available The mixed-metal rare-earth polyphosphate LiSm(PO34 consists of a three-dimensional framework in which zigzag [(PO3n]n− chains with a periodicity of four PO4 tetrahedra are connected through Li+ and Sm3+ ions (both with 2. symmetry.

  19. Sodium samarium tetrakis(polyphosphate, NaSm(PO34

    Directory of Open Access Journals (Sweden)

    Dan Zhao

    2010-07-01

    Full Text Available NaSm(PO34 has been prepared by solid state reactions. It belongs to type II of the structural family of MILnIII(PO34 compounds (MI = alkali metal and LnIII = rare earth metal and is composed of ∞(PO3n]n− polyphosphate chains with a repeating unit of four PO4 tetrahedra. The chains extend parallel to [100] and share O atoms with irregular SmO8 polyhedra, forming a three-dimensional framework which delimits tunnels occupied by Na+ cations in a distorted octahedral environment.

  20. Isotopic Ratios of Samarium by TIMS for Nuclear Forensic Application

    Energy Technology Data Exchange (ETDEWEB)

    Louis Jean, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Inglis, Jeremy David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    The isotopic ratio of Nd, Sm, and Gd can provide important information regarding fissile material (nuclear devices, reactors), neutron environment, and device yield. These studies require precise measurement of Sm isotope ratios, by either TIMS or MC-ICP-MS. There has been an increasing trend to measure smaller and smaller quantities of Sm bearing samples. In nuclear forensics 10-100 ng of Sm are needed for precise measurement. To measure sub-ng Sm samples using TIMS for nuclear forensic analysis.

  1. Synthesis of copper, silver, and samarium chalcogenides by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Ohtani, T.; Maruyama, K.; Ohshima, K. [Okayama Univ. of Science (Japan). Lab. for Solid State Chemistry

    1997-03-01

    CuInX{sub 2} (X = S, Se, Te), Ag{sub 2}S, Ag{sub 2}Se, Ag{sub 3}Te{sub 2}, Ag{sub 1.9}Te, AgCuSe, Sm{sub 3}Se{sub 4}, Sm{sub 2}Se{sub 3}, and SmTe were synthesized by a mechanical alloying method, using a high-energy planetary ball mill. The compounds were obtained by milling mixtures of the elements with desired ratios in agate or Cu-Be vials for 60--180 min.

  2. Oriented growth of thin films of samarium oxide by MOCVD

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Thin films of Sm2O3 have been grown on Si(100) and fused quartz by low-pressure chemical va- pour deposition using an adducted β-diketonate precursor. The films on quartz are cubic, with no preferred orientation at lower growth temperatures (~ 550°C), while they grow with a strong (111) orientation as the.

  3. 150 KVA Samarium Cobalt VSCF Starter Generator Electrical System

    Science.gov (United States)

    1978-12-01

    considerable hand labor. Addition of a provision for suitable electrical connection by the SCR manufacturer wou;d be desirable for production runs. Predicted...licen- sing the holder or any other person or corporation, or conveying any rights or permission to manufacture , use, or sell any patented invent,’n...tesile strength to contain the magnets and pole pieces up through the overspeed rating of the rotor. The cho.;en process uses maraging steel as the

  4. Optical properties of samarium doped zinc–tellurite glasses

    Indian Academy of Sciences (India)

    Glasses with the composition, (Sm2O3)(ZnO)(40–)(TeO2)(60), were prepared by conventional melt quenching method. The density, molar volume, and optical energy band gap of these glasses have been measured. The refractive index, molar refraction and polarizability of oxide ion have been calculated by using ...

  5. Effect of annealing on magnetic properties and silicide formation at ...

    Indian Academy of Sciences (India)

    Abstract. The interaction of Co (30 nm) thin films on Si (100) substrate in UHV using solid state mixing technique has been studied. Cobalt was deposited on silicon substrate using electron beam evaporation at a ... characterized by atomic force microscopy (AFM) and secondary ion mass spectroscopy (SIMS) in terms of the.

  6. Scanning MOKE investigation of ion-beam-synthesized silicide films

    Energy Technology Data Exchange (ETDEWEB)

    Gumarov, G.G., E-mail: ifoggg@gmail.com [Zavoisky Physical-Technical Institute of THE RAS, 10/7 Sibirsky Trakt, Kazan 420029, Tatarstan (Russian Federation); Kazan Federal University, 18 Kremlyovskaya St., Kazan 420008, Tatarstan (Russian Federation); Konovalov, D.A.; Alekseev, A.V. [Zavoisky Physical-Technical Institute of THE RAS, 10/7 Sibirsky Trakt, Kazan 420029, Tatarstan (Russian Federation); Petukhov, V.Yu. [Zavoisky Physical-Technical Institute of THE RAS, 10/7 Sibirsky Trakt, Kazan 420029, Tatarstan (Russian Federation); Kazan Federal University, 18 Kremlyovskaya St., Kazan 420008, Tatarstan (Russian Federation); Zhikharev, V.A. [Kazan State Technology University, 68 Karl Marx St., Kazan 420015, Tatarstan (Russian Federation); Nuzhdin, V.I.; Shustov, V.A. [Zavoisky Physical-Technical Institute of THE RAS, 10/7 Sibirsky Trakt, Kazan 420029, Tatarstan (Russian Federation)

    2012-07-01

    Fe ions with an energy of 40 keV were implanted into Si plates with the fluence varying in the range of (1.6-3.0) Multiplication-Sign 10{sup 17} ion/cm{sup 2} in the external magnetic field. Scanning magnetooptical Kerr effect (MOKE) studies have shown that all samples possess uniaxial anisotropy. Both the coercive field and the anisotropy field increase with fluence. It was suggested that induced anisotropy is caused by inverse magnetostriction.

  7. Effects of nitrogen annealing on surface structure, silicide formation ...

    Indian Academy of Sciences (India)

    2002; Froment et al 2003). Also, the ferromagnetic nature of cobalt makes it a suitable candidate for the magnetic record- ing industry. It is well known that in the case of metal sili- cides the post deposition processing plays a ..... to the formation of larger magnetic clusters as can be seen in AFM images. This in turn leads to a ...

  8. Electronic transport properties of tungsten silicide thin films

    Science.gov (United States)

    Martin, T. L.; Malhotra, V.; Mahan, J. E.

    1984-03-01

    Tungsten suicide thin films have been prepared by neutralized ion beam sputtering of the metal onto a polycrystalline silicon layer followed by furnace annealing. The films appear to be essentially sing le-phase disilicide with the possibility of a percent or so carbon and oxygen content. The material behaves as a classical metallic conductor, with a temperature-independent residual resistivity of 16 μΩ-cm and a room temperature intrinsic resistivity of 7 μΩ-cm. Hall effect measurements indicate the material is predominantly a hole conductor, with a room temperature Hall mobility of 30cm2/V-s and an apparent free carrier concentration of 8.9×1021 cm-3. The effective one-carrier mobility derived from geometrical magnetoresistance data, on the other hand, is ≈95 cm2/V-s; this difference, taken together with the effect of temperature on the transport properties, suggests there is mixed conduction.

  9. Milestone report on MD potential development for uranium silicide

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jianguo [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Zhang, Yongfeng [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Hales, Jason Dean [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.

    2016-03-01

    This report summarizes the progress on the interatomic potential development of triuranium-disilicide (U3Si2) for molecular dynamics (MD) simulations. The development is based on the Tersoff type potentials for single element U and Si. The Si potential is taken from the literature and a Tersoff type U potential is developed in this project. With the primary focus on the U3Si2 phase, some other U-Si systems such as U3Si are also included as a test of the transferability of the potentials for binary U-Si phases. Based on the potentials for unary U and Si, two sets of parameters for the binary U-Si system are developed using the Tersoff mixing rules and the cross-term fitting, respectively. The cross-term potential is found to give better results on the enthalpy of formation, lattice constants and elastic constants than those produced by the Tersoff mixing potential, with the reference data taken from either experiments or density functional theory (DFT) calculations. In particular, the results on the formation enthalpy and lattice constants for the U3Si2 phase and lattice constants for the high temperature U3Si (h-U3Si) phase generated by the cross-term potential agree well with experimental data. Reasonable agreements are also reached on the elastic constants of U3Si2, on the formation enthalpy for the low temperature U3Si (m-U3Si) and h-U3Si phases, and on the lattice constants of m-U3Si phase. All these phases are predicted to be mechanically stable. The unary U potential is tested for three metallic U phases (α, β, γ). The potential is found capable to predict the cohesive energies well against experimental data for all three phases. It matches reasonably with previous experiments on the lattice constants and elastic constants of αU.

  10. Silicide-to-silicon specific contact resistance characterization

    NARCIS (Netherlands)

    Stavitski, N.

    2009-01-01

    The performance of Si integrated circuits depends on the transistor drive current. The drive current of a MOS transistor is determined by the total device resistance, which consists of the channel resistance and the parasitic resistances associated with dopant diffusion areas and contacts. It is

  11. Effects of nitrogen annealing on surface structure, silicide formation ...

    Indian Academy of Sciences (India)

    Author Affiliations. Ganesh K Rajan1 Shivaraman Ramaswamy1 C Gopalakrishnan1 D John Thiruvadigal2. Nanotechnology Research Centre, SRM University, Kancheepuram District 603 203, India; Department of Physics, SRM University, Kancheepuram District 603 203, India ...

  12. Contribution to the study of samarium-151 excited levels; Contribution a l'etude des niveaux excites du samarium-151

    Energy Technology Data Exchange (ETDEWEB)

    Locard, P. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, 38 (France)

    1967-07-01

    The nucleus of {sup 151}Sm, which has 89 neutrons, happens to be on the lower edge of the deformed nuclei of region II. Therefore, the study of its levels is very interesting for the verification of the goodness of the collective models for deformed nuclei when the deformation is small (we introduce these models in the first chapter). {sup 151}Sm has often been studied, but the direct gamma spectrum measured with a lithium drift-germanium detector (chapter 3) shows many high energy transitions which did not appear in the previous level schemes. In order to settle these transitions, we have undertaken gamma-gamma coincidence spectra (as well as sum-coincidence spectra) experiments with a scintillation spectrometer designed in our laboratory (chapter 2). The investigation of the intensities of these coincidences leads us to modify the last proposed level schemes: we suppress the levels at 405,5 and 650 keV, we add levels at 245,6 - 306,6 - 522 - 952 and 962 keV. We have also verified the multipolarities of the main transitions and measured the half-lives of a few levels (chapter 3) (we find a half-life of 1.1 {+-} 0.5 nanosecond for the level at 167,7 keV). In chapter 4, we compare our results to the predictions of the models described in chapter 1. (author) [French] Le noyau de {sup 151}Sm, qui possede 89 neutrons, se trouve a la limite inferieure des noyaux deformes de la region II. L'etude de ses niveaux excites est donc d'un interet tout particulier pour la verification de la validite des differents modeles collectifs pour les noyaux deformes, lorsque la deformation est petite (nous introduisons ces modeles dans un premier chapitre). Le {sup 151}Sm a deja fait l'objet de nombreuses etudes, mais le spectre gamma direct fait avec une jonction de germanium compense au lithium (chapitre 3), nous a montre l'existence d'un grand nombre de transitions de hautes energies qui ne sont pas placees dans les schemas proposes jusqu'a ce jour. Pour preciser la place de ces transitions, nous avons donc entrepris des experiences de coincidences gamma-gamma (et de ''spectre de somme'') a l'aide d'un ensemble de spectrometrie a scintillation realise au laboratoire (chapitre 2). L'etude des intensites de ces coincidences (chapitre 3) nous amene a modifier le dernier schema propose: nous supprimons les niveaux a 405,5 et 650 keV, nous ajoutons des niveaux a 245,6 - 306,6 - 522 - 952 et 962 keV. Nous avons egalement verifie la multipolarite des principales transitions et mesure la duree de vie de certains des niveaux (chapitre 3) (nous trouvons une periode de 1,1 {+-} 0,5) nanoseconde pour le niveau a 167,7 keV). Le chapitre 4 est enfin consacre a la comparaison de nos resultats avec les predictions des differents modeles decrits au chapitre 1. (auteur)

  13. One-step synthesis of samarium-doped ceria and its CO catalysis

    Indian Academy of Sciences (India)

    Administrator

    Key Laboratory for Special Functional Aggregate Materials of Education Ministry,. School of Chemistry and Chemical ... been flourishing since its excellent electric properties were discovered in the 1980s.1 At present SDC is ... absolute ethanol three times and dried in an electric oven at 60°C overnight, and then calcined at ...

  14. Trichloridotris{N-[phenyl(pyridin-2-ylmethylidene]hydroxylamine-κ2N,N′}samarium(III

    Directory of Open Access Journals (Sweden)

    Yahong Li

    2012-03-01

    Full Text Available The SmIII ion in the title compound, [SmCl3(C12H10N2O3], shows a coordination number of nine with a slightly distorted tricapped trigonal prismatic geometry based on a Cl3N6 donor set. The molecular structure is stabilized by three intramolecular O—H...Cl hydrogen bonds.

  15. Biological studies of samarium-153 bleomycin complex in human breast cancer murine xenografts for therapeutic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami-Samani, A. [Faculty of Nuclear Engineering and Physics, Amirkabir Univ. of Tech., Tehran (Iran); Ghannadi-Maragheh, M. [Faculty of Nuclear Engineering and Physics, Amirkabir Univ. of Tech., Tehran (Iran); Radiopharmaceutical Research and Development Lab. (RRDL), Nuclear Science and Technology Research Inst. (NSTRI), Tehran (Iran); Jalilian, A.R.; Mazidi, M. [Radiopharmaceutical Research and Development Lab. (RRDL), Nuclear Science and Technology Research Inst. (NSTRI), Tehran (Iran)

    2010-07-01

    In this work, a potential therapeutic DNA targeting agent, {sup 153}Sm-bleomycin complex ({sup 153}Sm-BLM), was developed and the tumor accumulation studies were performed using single photon emission computed tomography (SPECT) and scarification studies. {sup 153}Sm-BLM was prepared at optimized conditions (room temperature, 4-8 h, 0.1 mg bleomycin for 740-3700 MBq {sup 153}SmCl{sub 3}, radiochemical purity over 98%, HPLC, specific activity = 55 TBq/mmol). {sup 153}Sm-BLM was administered into human breast cancer murine xenografts and the biodistribution and imaging studies were performed up to 48 h. {sup 153}Sm-BLM demonstrated superior tumor accumulation properties in contrast with the other radiolabeled bleomycins with tumor:blood ratios of 41, 72 and 182 at 4, 24 and 48 h, respectively, and tumor:muscle ratios of 23, 33 and > 1490 at 4, 24 and 48 h, respectively, while administered intravenously. The SPECT images also demonstrated the obvious tumor uptake at the chest region of the breast-tumor bearing mice. These initial experiments demonstrate significant accumulation of {sup 153}Sm-BLM in tumor tissues. (orig.)

  16. Samarium oxide as a radiotracer to evaluate the in vivo biodistribution of PLGA nanoparticles

    CSIR Research Space (South Africa)

    Mandiwana, V

    2015-09-01

    Full Text Available .63 %ID/g) and liver (3.07 %ID/g), confirming that nanoparticles are rapidly removed from the blood by the RES, leading to rapid uptake in the liver and spleen. From the biodistribution data obtained, it is clear that polymeric nanoscale delivery systems...

  17. Nanostructured Samarium Doped Fluorapatites and Their Catalytic Activity towards Synthesis of 1,2,4-Triazoles

    National Research Council Canada - National Science Library

    Gangu, Kranthi Kumar; Maddila, Suresh; Maddila, Surya Narayana; Jonnalagadda, Sreekantha B

    2016-01-01

    ...) and their properties. The nanostructured Sm doped fluorapatites (Sm-FAp) were prepared by a co-precipitation method using four different amino acids, namely glutamic acid, aspartic acid, glycine and histidine...

  18. Samarium(III) picrate tetraethylene glycol complex: Photoluminescence study and active material in monolayer electroluminescent

    Energy Technology Data Exchange (ETDEWEB)

    Kusrini, Eny, E-mail: ekusrini@che.ui.ac.id [Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, 16424 Depok (Indonesia); Saleh, Muhammad I. [School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Yulizar, Yoki [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, 16424 Depok (Indonesia); Za' aba, Noor K.; Abd. Majid, W.H. [Solid State Research Laboratory, Department of Physics, Universiti Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-09-15

    A mononuclear Sm(III) complex involving Pic and EO4 (where Pic=picrate anion and EO4=tetraethylene glycol) has been studied. It shows a bright-orange emission when used as active material in a monolayer electroluminescent device of ITO/EO4-Sm-Pic/Al. The crystal structure of the complex consists of [Sm(Pic){sub 2}(H{sub 2}O)(EO4)]{sup +} cation and [Pic]{sup -} anion. The Sm(III) ion is coordinated with nine oxygen atoms from one EO4 ligand in a pentadentate mode, two Pic anions each in bidentate and monodentate modes, and one water molecule. Both the terminal alcohol groups of the acyclic EO4 ligand were involved in the O-H...O hydrogen bonding by infinite one-dimensional (1D) chain within a symmetry direction [0 1 0]. The photoluminescence (PL) spectrum of the thin film shows the typical spectral features of the Sm(III) ion ({sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} transitions). The root-mean-square (rms) of the roughness of thin film is 30.605 nm and indicates that the formation of the monolayer electroluminescent device is not uniform and retains a high crystallinity. Typical semiconductor current-voltage (I-V) property was also observed in this device with threshold and turn voltages of 2.8 and 6.2 V, respectively. The [Sm(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).H{sub 2}O complex can be applied as a luminescent center in OLED for bright-orange emission. - Highlights: > The [Sm(Pic){sub 2}(H{sub 2}O)(EO4)](Pic).H{sub 2}O complex is crystallized in triclinic with space group P-1. > The complex is applied as a emissive center in monolayer device structure of ITO/EO4-Sm-Pic/Al. > The photoluminescence spectrum of the crystalline and thin film shows a bright-orange emission. > The current-voltage property showed the turn on voltage of 6.2 V.

  19. Pulsed laser deposition and optical characterizations of the magnetic samarium orthoferrite

    Energy Technology Data Exchange (ETDEWEB)

    Berini, Bruno, E-mail: bruno.berini@uvsq.fr [Groupe d' Etude de la Matiere Condensee (GEMAC), CNRS, Universite de Versailles St. Quentin, 45, Av. des Etats-Unis, 78035 Versailles Cedex (France); Mistrik, Jan [Institute of Applied Physics and Mathematics, Faculty of Chemical Technology, University of Pardubice, Studentska 84, 532 10 Pardubice (Czech Republic); Dumont, Yves; Popova, Elena; Fouchet, Arnaud; Scola, Joseph; Keller, Niels [Groupe d' Etude de la Matiere Condensee (GEMAC), CNRS, Universite de Versailles St. Quentin, 45, Av. des Etats-Unis, 78035 Versailles Cedex (France)

    2012-01-01

    Pulsed Laser Deposition of magnetically ordered polycrystalline SmFeO{sub 3} films has been optimized onto SiO{sub 2} glass substrates as function of substrate temperature, oxygen pressure and pulsed laser fluency. Using a KrF excimer laser, crystallization temperature is found to be about 1048 K for a weak fluency of only 1.7 J cm{sup -2}. We show that this growth temperature can be reduced using higher fluency and that it is possible to obtain a film texturation along the c axis by reducing the oxygen pressure at given temperature and fluency. In a second part, we focus on the SmFeO{sub 3} optical constants determined by in situ ellipsometry using a stacking model and the Cauchy dispersion relation for SmFeO{sub 3} layer. We show a good correlation between the transmission and reflection calculated from these data and measured by ex situ spectrophotometry in the visible range.

  20. Nanostructured Samarium Doped Fluorapatites and Their Catalytic Activity towards Synthesis of 1,2,4-Triazoles

    Directory of Open Access Journals (Sweden)

    Kranthi Kumar Gangu

    2016-09-01

    Full Text Available An investigation was conducted into the influence of the amino acids as organic modifiers in the facile synthesis of metal incorporated fluorapatites (FAp and their properties. The nanostructured Sm doped fluorapatites (Sm-FAp were prepared by a co-precipitation method using four different amino acids, namely glutamic acid, aspartic acid, glycine and histidine. The materials were characterized by various techniques including X-ray diffraction (XRD, Fourier transform infra-red spectroscopy (FT-IR, field emission scanning electron microscopy (FE-SEM, energy-dispersive X-ray spectroscopy (EDX, high resolution transmission electron microscopy (HR-TEM, N2-adsorption/desorption isotherm, temperature programmed desorption (TPD and fluorescence spectrophotometry. Under similar conditions, Sm-FAp prepared using different amino acids exhibited distinctly different morphological structures, surface area and pore properties. Their activity as catalysts was assessed and Sm-FAp/Glycine displayed excellent efficiency in the synthesis of 1,2,4-triazole catalyzing the reaction between 2-nitrobenzaldehyde and thiosemicarbazide with exceptional selectivity and 98% yield in a short time interval (10 min. The study provides an insight into the role of organic modifiers as controllers of nucleation, growth and aggregation which significantly influence the nature and activity of the catalytic sites on Sm-FAp. Sm-FAp could also have potential as photoactive material.

  1. Body composition analysis by DEXA by using dynamically changing samarium filtration

    DEFF Research Database (Denmark)

    Gotfredsen, Arne; Baeksgaard, L; Hilsted, J

    1997-01-01

    , which depends on the current-absorber thickness. With this system we found a good agreement (r = 0.99) between reference and measured amounts of tissue or fat percentages in a plastic phantom and in smaller (approximately 0.5-4 kg) and larger (approximately 5-20 kg) piles of tissue (ox muscle and lard......). Scans of six healthy volunteers covered with combinations of beef and lard (approximately 5-15 kg) showed a good agreement (r = 0.99) between reference and DEXA values of added soft tissue mass and fat percentage. We conclude that the DEXA method (and, in particular, the Norland XR-36 using dynamic...

  2. Synthesis, thermal and photoluminescent properties of ZnSe- based oxyfluoride glasses doped with samarium

    Science.gov (United States)

    Kostova, I.; Okada, G.; Pashova, T.; Tonchev, D.; Kasap, S.

    2014-12-01

    Rare earth (RE) doped glasses and glass ceramic materials have recently received considerable attention because of their potential or realized applications as X-ray intensifying screens, phosphors, detectors, waveguides, lasers etc. [1]. In this work, we present a new RE doped ZnO-ZnSe-SrF2-P2O5-B2O3-Sm2O3-SmF3 (ZSPB) glass system synthesized by melt quenching technique. The resulting glasses were visually fully transparent and stable with glass the transition temperatures around 530°C. The thermal properties of this glass system were characterized by Modulated Differential Scanning Calorimetry (MDSC) measurements before and after annealing at 650°C. We have characterized these glasses by Raman spectroscopy and photoluminescence (PL) measurements over the UV-VIS range using light emitting diodes (LED) and laser diodes (LD) excitation sources. We have also irradiated thermally treated and non-treated glass samples by X-rays and have studied the resulting PL. We discuss the results in terms of previously reported models for Sm-doped Zn-borophosphate oxide, oxyfluoride and oxyselenide glasses.

  3. Laser-Induced Luminescence Study of Samarium(III) Thiodiglycolate Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Dong Yong; Lee, Eil Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kimura, Takaumi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)

    2003-09-15

    The hydration number of Sm(III) has been obtained by using the difference in the decay rate constants in H{sub 2}O and D{sub 2}O solutions. In general, k{sub obs}(H{sub 2}O) >> k{sub obs}(D{sub 2}O), k{sub obs}(D{sub 2}O) ≅ constant, and ligands are not as effective in causing non-radiative de-excitation of the excited state. For Sm(III), a relationship has been proposed in which the hydration number is related directly to the decay rate constant in H{sub 2}O. If there is no contribution from the ligand to the de-excitation of the luminescence excited state, the hydration of Sm(III) in the different complexes can be obtained directly from the values of k{sub obs} measured in H{sub 2}O. The number and the geometric distribution of solvent molecules around a metal ion in solution are an important factor in the structural and chemical behavior of cation. Indeed, such information has been utilized to design novel ionophores and receptors. However, there have been few studies of hydration structure for lanthanides. The fact that many f-element salts which have relatively large lattice energies are fairly soluble in water is a reflection of the strength of the interactions between the metal cations and water molecules.

  4. Oxygen Fugacity of the Martian Mantle from Pigeonite/Melt Partitioning of Samarium, Europium and Gadolinium

    Science.gov (United States)

    Musselwhite, S.; Jones, J. H.; Shearer, C.

    2004-01-01

    This study is part of an ongoing effort to calibrate the pyroxene/melt Eu oxybarometer for conditions relevant to the martian meteorites. There is fairly good agreement between a determinations using equilibria between Fe-Ti oxides and the estimates from Eu anomalies in shergottite augites in tenns of which meteorites are more or less oxidized. The Eu calibration was for angrite composition pyroxenes which are rather extreme. However, application of a calibration for martian composition augites 113 does not significantly reduce the discrepancy between the two methods. One possible reason for this discrepancy is that augites are non-liquidus. The use of pigeonite rather than augite as the oxy-barometer phase is considered. We have conducted experiments on martian composition pigeonite/melt REE partitioning as a function of fO2.

  5. Doping controlled spin reorientation in dysprosium-samarium orthoferrite single crystals

    Science.gov (United States)

    Cao, Shixun; Zhao, Weiyao; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2015-03-01

    As one of the most important phase transitions, spin reorientation (SR) in rare earth transition metal oxides draws much attention of emerging materials technologies. The origin of SR is the competition between different spin configurations which possess different free energy. We report the control of spin reorientation (SR) transition in perovskite rare earth orthoferrite Dy1-xSmxFeO3, a whole family of single crystals grown by optical floating zone method from x =0 to 1. Temperature dependence of the magnetizations under zero-field-cooling (ZFC) and field-cooling (FC) processes are studied. We have found a remarkable linear change of SR transition temperature in Sm-rich samples for x>0.2, which covers an extremely wide temperature range including room temperature. The a-axis magnetization curves under FCC process bifurcate from and then jump down to that of warming process (ZFC and FCW curves) in single crystals when x =0.5-0.9, suggesting complicated 4f-3d electron interactions among Dy3+-Sm3+, Dy3+-Fe3+, and Sm3+-Fe3+ sublattices of diverse magnetic configurations for materials physics and design. The magnetic properties and the doping effect on SR transition temperature in these single crystals might be useful in the spintronics device application. This work is supported by the National Key Basic Research Program of China (Grant No. 2015CB921600), and the National Natural Science Foundation of China (NSFC, Nos. 51372149, 50932003, 11274222).

  6. Synthesis, crystal structure and luminescent properties of a new samarium-fluorescein metal-organic framework

    Science.gov (United States)

    Thomas, Jesty; Ambili, K. S.

    2015-10-01

    A new metal-organic framework with empirical formula C43H30NO12Sm was solvothermally synthesized using SmCl3, fluorescein and N, N-Dimethyl formamide (DMF) and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, UV-Visible spectroscopy, scanning electron microscopy, optical microscopy, photoluminescence spectroscopy, CHN elemental analysis and thermogravimetric analysis. Single crystal X-ray diffraction revealed that the crystal structure belongs to the triclinic system, P-1 space group with a = 12.113 (6) Å, b = 12.1734 (7) Å, c = 13.2760(8) Å, α = 67.930(3)⁰, β = 87.779(3)⁰, γ = 77.603(3)⁰ and V = 1769.71 (17) Å3. The photoluminescence spectrum showed emission peaks at 550 nm, 600 nm and 647 nm due to the characteristic transitions 4G5/2 to 6H5/2, 4G5/2 to 6H7/2 and 4G5/2 to 6H9/2 respectively, when excited at 398 nm.

  7. High-temperature heat capacity of samarium and erbium titanates with pyrochlore structure

    Science.gov (United States)

    Denisova, L. T.; Chumilina, L. G.; Denisov, V. M.; Ryabov, V. V.

    2017-12-01

    Titanates Sm2Ti2O7 and Er2Ti2O7 with pyrochlore structure have been prepared by solid-phase synthesis in air from stoichiometric Sm2O3 (Er2O3)-TiO2 mixtures sequentially at 1673 and 1773 K. Hightemperature heat capacity of the oxide compounds has been determined by differential scanning calorimetry. Their thermodynamic properties have been calculated from experimental temperature dependence C p = f( T).

  8. Thermal stability of iron silicide nanowires epitaxially grown on Si(110) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Zhi-Qiang, E-mail: zouzhq@shanghaitech.edu.cn [School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Pudong, Shanghai, 201210 (China); Li, Xu; Liu, Xiao-Yong; Shi, Kai-Juan; Guo, Xin-Qiu [Analytical and Testing Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2017-03-31

    Highlights: • The α-FeSi{sub 2} nanowires epitaxially grown on Si(110) can be stable up to 750 °C. • The stable temperature of the nanowires is much lower than that of the bulk α-FeSi{sub 2} due to their small size and high relative surface area. • With increasing annealing temperature, the α-FeSi{sub 2} nanowires undergo an Ostwald ripening process and transform into large β-FeSi{sub 2} nanorods or three-dimensional nanocrystals. • The reduction in surface energy drives the transformation from metallic α-FeSi{sub 2} phase to semiconducting β-FeSi{sub 2} phase. - Abstract: Metallic α-FeSi{sub 2} nanowires (NWs) are epitaxially grown on Si(110) at 650 °C. Their evolution as a function of annealing temperature has been studied in situ by scanning tunneling microscopy. The NWs are stable up to 750 °C, which is much lower than that of the bulk α-FeSi{sub 2}. With further increasing the annealing temperature, some NWs begin to shrink in length and transform into wider and higher semiconducting β-FeSi{sub 2} nanorods or three-dimensional (3D) islands at 925 °C. The phase transformation is driven by the reduction in surface energy. On the other hand, some α-FeSi{sub 2} NWs begin to dissolve and become thinner until disappearing. The growth of the β-FeSi{sub 2} nanorods or 3D nanocrystals follows the Ostwald ripening mechanism, i.e., the large islands grow in size at the expense of the small ones. X-ray photoelectron spectroscopy study shows that the Fe 2p peaks of β-FeSi{sub 2} nanocrystals exhibit a negative shift of 0.2 eV with respect to the α-FeSi{sub 2} NWs.

  9. Tungsten/Magnesium silicide multilayers for soft x-ray optics.

    Science.gov (United States)

    Boher, P; Houdy, P; Kühne, M; Müller, P; Barchewitz, R; Delaboudiniere, J P; Smith, D J

    1992-01-01

    W/Mg2Si multilayers for soft x-ray optics above the MgKα and MgLα lines have been deposited by RF sputtering. Their structural characteristics have been deduced from in situ kinetic ellipsometry, ex situ grazing x-ray reflection measurements, and high-resolution electron microscopy. Their soft x-ray performances have been measured by synchrotron radiation around the MgKα and MgLα lines and related to the structural characteristics. For short wavelengths, first Bragg peak reflectivities as high as 31% have been measured for multilayers with double period equal to 84 Å. For samples with smaller layer thicknesses, these performances decrease due to finite interdiffusion at the interfaces. Nevertheless, well-defined Bragg peaks are observed even when the double period is as low as 44 Å. Near the MgLα line, more than 20% reflectivity at the first Bragg peak has been measured at normal incidence. At the same wavelength the selectivity is two times higher than that of conventional systems such as Mo/Si.

  10. Role of milling parameters and impurity on the thermoelectric properties of mechanically alloyed chromium silicide

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, T. [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India); Umarji, A.M. [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India)], E-mail: umarji@mrc.iisc.ernet.in

    2008-08-11

    Mechanical alloying of Cr-Si powders (1:2 molar ratio) was carried out under different milling conditions using stainless steel milling media. In addition to formation of nanocrystalline CrSi{sub 2} phase, depending on the milling duration, speed and use of dispersant, X-ray diffraction revealed presence of CrSi phase and EDAX showed iron contamination in varying amounts. The amount of contamination and the secondary phase are found to be linearly proportional to the input impact energy during milling. The nanocrystalline powders are seen to be thermally stable in air up to 900 K. SEM of the hot pressed powders reveal an equiaxed microstructure with grain size depending on the milling duration. Electrical resistivity ({rho}), Seebeck coefficient (S) and thermal conductivity (K) were measured up to 700 K. It is seen that the thermoelectric figure of merit (ZT) is high when the amount of secondary phases is minimum. The maximum ZT observed in the samples is {approx}0.2 at 600 K which is comparable to other high temperature thermoelectric materials in the temperature range studied.

  11. Comparison of the Thermal Expansion Behavior of Several Intermetallic Silicide Alloys Between 293 and 1523 K

    Science.gov (United States)

    Raj, S. V.

    2015-03-01

    Thermal expansion measurements were conducted on hot-pressed CrSi2, TiSi2, WSi2 and a two-phase Cr-Mo-Si intermetallic alloy between 303 and 1523 K during three heat-cool cycles. The corrected thermal expansion, (Δ L/ L 0)thermal, varied with the absolute temperature, T, as where, A, B, C, and D are regression constants. Excellent reproducibility was observed for most of the materials after the first heat-up cycle. In some cases, the data from first heat-up cycle deviated from those determined in the subsequent cycles. This deviation was attributed to the presence of residual stresses developed during processing, which are relieved after the first heat-up cycle.

  12. Development of Low-Noise High Value Chromium Silicide Resistors for Cryogenic Detector Applications

    Science.gov (United States)

    Jhabvala, Murzy; Babu, Sachi; Monroy, Carlos; Darren, C.; Krebs, Carolyn A. (Technical Monitor)

    2001-01-01

    Extremely high sensitivity detectors, such as silicon bolometers are required in many NASA missions for detection of photons from the x-ray to the far infrared regions. Typically, these detectors are cooled to well below the liquid helium (LHe) temperature (4.2 K) to achieve the maximum detection performance. As photoconductors, they are generally operated with a load resistor and a pre-set bias voltage, which is then coupled to the input gate of a source-follower Field Effect Transistor (FET) circuit. It is imperative that the detector system signal to noise performance be limited by the noise of the detector and not by the noise of the external components. The load resistor value is selected to optimize the detector performance. These two criteria tend to be contradictory in that these detectors require load resistors in the hundreds of megaohms, which leads to a higher Johnson noise. Additionally, the physical size of the resistor must be small for device integration as required by such missions as the NASA High Resolution Airborne Wide-Band Camera (HAWC) instrument and the Submillimeter High Angular Resolution Camera (SHARC) for the Caltech Submillimeter Observatory (CSO). We have designed, fabricated and characterized thin film resistors using a CrSi/TiW/Al metal system on optical quality quartz substrates. The resistor values range from 100 megaohms to over 650 megaohms and are Johnson noise limited at LHe temperatures. The resistor film is sputtered with a sheet resistance ranging from 300 ohms to 1600 ohms and the processing sequence developed for these devices allows for chemically fine tuning the sheet resistance in-situ. The wafer fabrication process was of sufficiently high yield (>80%) providing clusters of good resistors for integrated multiple detector channels, a very important feature in the assembly of these two instruments.

  13. Mechanical Properties of Uranium Silicides by Nanoindentation and Finite Elements Modeling

    Science.gov (United States)

    Carvajal-Nunez, U.; Elbakhshwan, M. S.; Mara, N. A.; White, J. T.; Nelson, A. T.

    2018-02-01

    Three methods were used to measure the mechanical properties of {U}3{Si}, {U}_3{Si}2, and USi. Quasi-static and continuous stiffness measurement nanoindentation were used to determine hardness and Young's modulus, and microindentation was used to evaluate the bulk hardness. Hardness and Young's modulus of the three U-Si compounds were both observed to increase with Si content. Finally, finite elements modelling was used to validate the nanoindentation data calculated for {U}3{Si}2 and estimate its yield strength.

  14. Pulsed laser synthesis of titanium silicides using a Q-Switched Nd: Glass laser

    Science.gov (United States)

    D'Anna, E.; Leggieri, G.; Luches, A.; Luby, S.; Zemek, J.

    1989-06-01

    Titanium films 120 nm thick deposited on single-crystalline silicon (c-Si) as well as poly-Si/SiO2/c-Si substrates were subjected to Nd: glass laser irradiation. Laser fluences of 1,1.5, and 2 J/cm2 were used at the pulse duration of 30 ns. From RBS analysis it follows that on c-Si substrate titanium suicide is formed using one pulse of 1.5 J/cm2 energy density. On the substrate with surface overlayers lower fluence (1 J/cm2) was sufficient. Under these conditions the sheet resistance of the samples decreased from the initial value 5 Ω/□ to 2 3 Ω/□. The smaller threshold density of energy for suicide formation in Ti/polySi/SiO2/c-Si structure is shown to be a consequence of the SiO2 underlayer, which is a poorer heat conductor than silicon. The experimental results of the suicide synthesis are in semi-quantitative accordance with the numerical computations of the temperature vs time evolution and depth temperature distribution in our samples.

  15. Silicide formation by furnace annealing of thin Si films on large-grained Ni substrates

    Science.gov (United States)

    Brunner, A. J.; Ma, E.; Nicolet, M.-A.

    1989-03-01

    Si films with a thickness of approximately 250 nm have been electron-beam evaporated on thick, large-grained Ni substrates (grain size a few mm to 1 cm in diameter). An in situ sputter cleaning procedure has been used to clean the Ni surface before the Si deposition. Thermal annealings have been performed in a vacuum furnace. Ni2Si is the first phase that grows at temperatures between 240 °C and 300 °C as a laterally uniform interfacial layer with a diffusion-controlled kinetics. The layer thickness x follows the growth law x 2= kt, with k=k 0 exp(- E a k B T), where k 0=6.3 × 10-4cm 2/s and E a=(1-1±0.1) eV. Because of the virtually infinite supply of Ni, annealing at 800 °C for 130min yields a Ni-based solid solution as the final phase. The results are compared with those reported in the literature on suicide formation by the reaction of a thin Ni film on Si substrates, as well as with those for interfacial phase formation in Ni/Zr bilayers.

  16. Sputter behaviour of vanadium silicide studied by a computer simulation technique

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsch, B.; Zehe, A.; Samoylov, V.N.

    1986-11-01

    A detailed study of the sputter yield of VSi/sub 2/ has been carried out by a computer simulation technique. Krypton and neon ions in the energy range of 200 - 5000 eV are used, and the angle of incidence on the (0001) surface of VSi/sub 2/ is taken to be 90/sup 0/. The dynamical atom block considered in the computer program consists of 397 atoms situated at 5 equally spaced layers. Both amorphous and crystalline targets are discussed, having expectingly a different outcome for yield, as well as for preferential and directional sputtering. Theoretical results are in good accord with experimental findings.

  17. Electrophoretic deposition of magnesium silicates on titanium implants: Ion migration and silicide interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Afshar-Mohajer, M. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yaghoubi, A., E-mail: yaghoubi@siswa.um.edu.my [Center for High Impact Research, University of Malaya, Kuala Lumpur 50603 (Malaysia); Ramesh, S., E-mail: ramesh79@um.edu.my [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Bushroa, A.R.; Chin, K.M.C.; Tin, C.C. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chiu, W.S. [Low Dimensional Materials Research Center, Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2014-07-01

    Magnesium silicates (Mg{sub x}SiO{sub y}) and in particular forsterite (Mg{sub 2}SiO{sub 4}) owing to their low thermal expansion mismatch with metals are promising materials for bioactive coating of implants. Here, we report the electrophoretic deposition (EPD) of forsterite onto titanium substrates using different precursors. Unlike bulk samples which achieve full stoichiometry only beyond 1400 °C, non-stoichiometric magnesium silicate rapidly decomposes into magnesium oxide nanowires during sintering. Elemental mapping and X-ray diffraction suggest that oxygen diffusion followed by ion exchange near the substrate leads to formation of an interfacial Ti{sub 5}Si{sub 3} layer. Pre-annealed forsterite powder on the other hand shows a comparatively lower diffusion rate. Overall, magnesium silicate coatings do not exhibit thermally induced microcracks upon sintering as opposed to calcium phosphate bioceramics which are currently in use.

  18. Thin film molybdenum silicide as potential temperature sensors for turbine engines

    Science.gov (United States)

    Ho, C. H.; Prakash, S.; Deshpandey, C. V.; Doerr, H. J.; Bunshah, R. F.

    1989-01-01

    Temperature measurements of Mo-Si-based thin-film resistance thermometers were studied. Annealing in an argon ambient at a temperature above 1000 C for at least 1 h is required to form the stable tetragonal MoSi2 phase. With a crack-free 2-micron-thick AlN barrier layer on top, a sensor was tested up to 1200 C. The resistivity vs temperature characteristic shows the room temperature resistivity and temperature coefficient of resistivity (TCR) of the sensor to be approximately 350 microohm and 0.01195 K, respectively. No film adhesion problems were observed for at least four testing cycles.

  19. Nickel Silicide Metallization for Passivated Tunneling Contacts for Silicon Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Alexander; Florent, Karine; Tapriya, Astha; Lee, Benjamin G.; Kurinec, Santosh K.; Young, David L.

    2016-11-21

    Passivated tunneling contacts offer promise for applications in Interdigitated Back Passivated Contact (IBPC) high efficiency silicon solar cells. Metallization of these contacts remains a key research topic. This paper investigates NiSi/poly-Si/SiO2/c-Si passivated contacts using photoluminescence and contact resistivity measurements. An amorphous Si interlayer between the NiSi and poly-Si is observed to improve passivation, decreasing recombination. The overall recombination loss has a linear trend with the NiSi thickness. Implied Voc values close to 700 mV and contact resistivities below 10 mohm-cm2 have been achieved in NiSi/poly-Si:P/SiO2/c-Si contacts.

  20. Study of Nickel Silicide as a Copper Diffusion Barrier in Monocrystalline Silicon Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Abhijit; Beese, Emily; Saenz, Theresa; Warren, Emily; Nemeth, William; Young, David; Marshall, Alexander; Florent, Karine; Kurinec, Santosh K.; Agarwal, Sumit; Stradins, Pauls

    2016-11-21

    NiSi as a conductive diffusion barrier to silicon has been studied. We demonstrate that the NiSi films formed using the single step annealing process are as good as the two step process using XRD and Raman. Quality of NiSi films formed using e-beam Ni and electroless Ni process has been compared. Incomplete surface coverage and presence of constituents other than Ni are the main challenges with electroless Ni. We also demonstrate that Cu reduces the thermal stability of NiSi films. The detection of Cu has proven to be difficult due to temperature limitations.

  1. Loading rate and test temperature effects on fracture of In Situ niobium silicide-niobium composites

    Science.gov (United States)

    Rigney, Joseph D.; Lewandowski, John J.

    1996-10-01

    Arc cast, extruded, and heat-treated in situ composites of niobium suicide (Nb5Si3) intermetallic with niobium phases (primary—Nbp and secondary—Nbs) exhibited high fracture resistance in comparison to monolithic Nb5Si3. In toughness tests conducted at 298 K and slow applied loading rates, the fracture process proceeded by the microcracking of the Nb5Si3 and plastic deformation of the Nbp and Nbs phases, producing resistance-curve behavior and toughnesses of 28 MPa√m with damage zone lengths less than 500 μm. The effects of changes in the Nbp yield strength and fracture behavior on the measured toughnesses were investigated by varying the loading rates during fracture tests at both 77 and 298 K. Quantitative fractography was utilized to completely characterize each fracture surface created at 298 K in order to determine the type of fracture mode ( i.e., dimpled, cleavage) exhibited by the Nbp. Specimens tested at either higher loading rates or lower test temperatures consistently exhibited a greater amount of cleavage fracture in the Nbp, while the Nbs, always remained ductile. However, the fracture toughness values determined from experiments spanning six orders of magnitude in loading rate at 298 and 77 K exhibited little variation, even under conditions when the majority of Nbp phases failed by cleavage at 77 K. The changes in fracture mode with increasing loading rate and/or decreasing test temperature and their effects on fracture toughness are rationalized by comparison to existing theoretical models.

  2. MOKE investigation of silicide films ion-beam synthesized in single-crystal silicon

    Energy Technology Data Exchange (ETDEWEB)

    Gumarov, G.G., E-mail: gumarov@kfti.knc.ru [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Kazan (Volga Region) Federal University, Kremlyovskaya St. 18, 420008 Kazan (Russian Federation); Petukhov, V.Yu., E-mail: petukhov@kfti.knc.ru [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Kazan (Volga Region) Federal University, Kremlyovskaya St. 18, 420008 Kazan (Russian Federation); Gumarov, A.I., E-mail: amirgumarov@rambler.ru [Kazan (Volga Region) Federal University, Kremlyovskaya St. 18, 420008 Kazan (Russian Federation); Khalikov, R.A., E-mail: khalikoff@gmail.com [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Konovalov, D.A., E-mail: dak@kfti.knc.ru [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Valeev, V.F., E-mail: rik@kfti.knc.ru [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Khaibullin, R.I., E-mail: rik@kfti.knc.ru [Zavoisky Physical-Technical Institute of RAS, Sibirsky tract 10/7, 420029 Kazan (Russian Federation); Kazan (Volga Region) Federal University, Kremlyovskaya St. 18, 420008 Kazan (Russian Federation)

    2012-02-01

    Magnetic-field-assisted ion-beam synthesis was used to produce thin magnetic films. Si wafers were implanted with 40 keV Fe{sup +} ions with a fluence of 3 Multiplication-Sign 10{sup 17} cm{sup -2} in the external magnetic field of 9.6 Multiplication-Sign 10{sup 4} A/m. The samples were investigated by scanning magneto-optical Kerr effect magnetometry, inductive magnetometry and reflection high-energy electron diffraction. The main synthesized phase was ferromagnetic Fe{sub 3}Si. In some regions of the samples the deviations of the easy magnetic axis near the applied magnetic field were revealed. These local changes can be caused by various reasons: the presence of mechanical stresses in a silicon substrate during the ion bombardment, the appearance of temperature gradients, inhomogeneous sputtering and the appearance of small magnetic fields in the chamber of the accelerator.

  3. High-Temperature Compatible Nickel Silicide Thermometer And Heater For Catalytic Chemical Microreactors

    DEFF Research Database (Denmark)

    Jensen, Søren; Quaade, U.J.; Hansen, Ole

    2005-01-01

    for temperatures exceeding 700 °C. The heaters and thermometers are integrated with chemical microreactors for heterogeneous catalytic conversion of gasses, and thermally activated catalytic conversion of CO to CO2 in the reactors is demonstrated. The heaters and thermometers are shown to be compatible...

  4. Pressure-induced structural transformations of the Zintl phase sodium silicide

    Science.gov (United States)

    Cabrera, Raúl Quesada; Salamat, Ashkan; Barkalov, Oleg I.; Leynaud, Olivier; Hutchins, Peter; Daisenberger, Dominik; Machon, Denis; Sella, Andrea; Lewis, Dewi W.; McMillan, Paul F.

    2009-09-01

    The high-pressure behaviour of NaSi has been studied using Raman spectroscopy and angle-dispersive synchrotron X-ray diffraction to observe the onset of structural phase transformations and potential oligomerisation into anionic Si nanoclusters with extended dimensionality. Our studies reveal a first structural transformation occurring at 8-10 GPa, followed by irreversible amorphisation above 15 GPa, suggesting the formation of Si-Si bonds with oxidation of the Si - species and reduction of Na + to metallic sodium. We have combined our experimental studies with DFT calculations to assist in the analysis of the structural behaviour of NaSi at high pressure.

  5. Ion beam synthesis and characterization of yttrium silicide in Si(111)

    Energy Technology Data Exchange (ETDEWEB)

    Ayache, R. [Pharmacy Department, University of Batna, 05000 (Algeria)], E-mail: ayache_r@yahoo.fr; Bouabellou, A. [Laboratoire Couches Minces et Interfaces, Campus Chaab Errassas, Universite Mentouri de Constantine, 25000 (Algeria); Eichhorn, F.; Richter, E.; Muecklich, A. [Forschungszentrum Rossendorf, Institute of Ion Beam Physics and Materials Research, POB 510119, D-01314 Dresden (Germany)

    2007-09-15

    Thin YSi{sub 2-x} layers are formed by 195 keV Y ion implantation in Si(111) substrates to a dose of 2 x 10{sup 17} Y{sup +}/cm{sup 2} at 500 deg. C followed by annealing in nitrogen atmosphere at different temperatures for 1 h. The investigation of the phase composition is carried out by Rutherford backscattering spectrometry (RBS), whereas the structural characterization is accomplished by means of both X-ray diffraction (XRD) pole figure and cross-sectional transmission electron microscopy (XTEM). The results show that the YSi{sub 2-x} layers grown on the Si has the epitaxial relationship of YSi{sub 2-x} (0 0 0 1)//Si(111) and YSi{sub 2-x} [1 1 - 2 0 ]//Si [110].

  6. Soft-x-ray fluorescence study of buried silicides in antiferromagnetically coupled Fe/Si multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Carlisle, J.A.; Chaiken, A.; Michel, R.P. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Multilayer films made by alternate deposition of two materials play an important role in electronic and optical devices such as quantum-well lasers and x-ray mirrors. In addition, novel phenomena like giant magnetoresistance and dimensional crossover in superconductors have emerged from studies of multilayers. While sophisticated x-ray techniques are widely used to study the morphology of multilayer films, progress in studying the electronic structure has been slower. The short mean-free path of low-energy electrons severely limits the usefulness of photoemission and related electron free path of low-energy electrons severely limit spectroscopies for multilayer studies. Soft x-ray fluorescence (SXF) is a bulk-sensitive photon-in, photon-out method to study valence band electronic states. Near-edge x-ray absorption fine-structure spectroscopy (NEXAFS) measured with partial photon yield can give complementary bulk-sensitive information about unoccupied states. Both these methods are element-specific since the incident x-ray photons excite electrons from core levels. By combining NEXAFS and SXF measurements on buried layers in multilayers and comparing these spectra to data on appropriate reference compounds, it is possible to obtain a detailed picture of the electronic structure. Results are presented for a study of a Fe/Si multilayer system.

  7. Thermal stability of iron silicide nanowires epitaxially grown on Si(110) substrates

    Science.gov (United States)

    Zou, Zhi-Qiang; Li, Xu; Liu, Xiao-Yong; Shi, Kai-Juan; Guo, Xin-Qiu

    2017-03-01

    Metallic α-FeSi2 nanowires (NWs) are epitaxially grown on Si(110) at 650 °C. Their evolution as a function of annealing temperature has been studied in situ by scanning tunneling microscopy. The NWs are stable up to 750 °C, which is much lower than that of the bulk α-FeSi2. With further increasing the annealing temperature, some NWs begin to shrink in length and transform into wider and higher semiconducting β-FeSi2 nanorods or three-dimensional (3D) islands at 925 °C. The phase transformation is driven by the reduction in surface energy. On the other hand, some α-FeSi2 NWs begin to dissolve and become thinner until disappearing. The growth of the β-FeSi2 nanorods or 3D nanocrystals follows the Ostwald ripening mechanism, i.e., the large islands grow in size at the expense of the small ones. X-ray photoelectron spectroscopy study shows that the Fe 2p peaks of β-FeSi2 nanocrystals exhibit a negative shift of 0.2 eV with respect to the α-FeSi2 NWs.

  8. Fluorescence enhancement of samarium (III) perchlorate by 1,10-phenanthroline on Phenylnaphthoylmethyl sulfoxide complex and luminescence mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Xian, E-mail: nmglwx@163.com; Feng, Shu-Yan; Liu, Yu; Zhang, Jing; Xin, Xiao-Dong; Ao, Bo-Yang; Li, Ying-Jie

    2013-11-15

    A novel ligand, Phenylnaphthoylmethyl sulfoxide, was synthesized by a new method. Its novel binary complex, SmL{sub 5}·(ClO{sub 4}){sub 3}·2H{sub 2}O, and the ternary complex, SmL{sub 4}·L′(ClO{sub 4}){sub 3}·2H{sub 2}O, had been synthesized (using Phenylnaphthoylmethyl sulfoxide as the first ligand L, 1,10-phenanthroline as the second ligand L′). The complexes were characterized by element analysis, coordination titration, molar conductivity, IR, TG-DSC, {sup 1}HNMR and UV spectra. Their fluorescence emission mechanism, fluorescence intensities and phosphorescence spectra of the two ligands were also investigated by comparison. Fluorescent spectra illustrated that the ternary rare-earth complex presented stronger fluorescence intensity than the binary rare-earth complex in such material. The strongest characteristic fluorescence emission intensity of the ternary system was 1.81 times as strong as that of the binary system. By the analysis of fluorescence and phosphorescence spectra, it was found that the Phenylnaphthoylmethyl sulfoxide and phen had the advantage to absorb and transfer energy to Sm (III) ions effectively, and then the complexes emitted the characteristic fluorescence of Sm (III) ions. The phosphorescence spectra and fluorescence lifetime of the complexes were also measured. -- Highlights: • A novel ligand, Phenylnaphthoylmethyl sulfoxide, has been synthesized. • Its novel ternary complex and the binary complex have been synthesized. • The fluorescence emission intensity of ternary rare earth complex exhibit obvious enhancement. • The fluorescence emission mechanism and phosphorescence spectra are also investigated.

  9. Polypropylene oil as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-03-01

    The research focusses on converting polypropylene oil as pyrolysis product of polypropylene plastic into an electricity. The converter was a direct liquid fuel-solid oxide fuel cell (SOFC) with cerium oxide based material as electrolyte. The polypropylene vapor flowed into fuel cell, in the anode side and undergo oxidation reaction, meanwhile, the Oxygen in atmosphere reduced into oxygen ion at cathode. The fuel cell test was conducted at 400 - 600 °C. According to GC-MS analysis, the polypropylene oil consist of C8 to C27 hydrocarbon chain. The XRD analysis result shows that Na2CO3 did not change the crystal structure of SDC even increases the electrical conductivity. The maximum power density is 0.079 mW.cm-2 at 773 K. The open circuite voltage is 0.77 volt. Chemical stability test by analysing the single cell at before and after fuel cell test found that ionic migration occured during fuel cell operation. It is supported by the change of elemental composition in the point position of electrolyte and at the electrolyte-electrode interface

  10. A distribution pattern of cadmium, gadolinium and samarium in Phaseolus vulgaris (L) plants as assessed by dynamic neutron radiography

    Science.gov (United States)

    Kőrösi, Ferenc; Balaskó, Márton; Sváb, Erzsébet

    1999-11-01

    The qualitative and semi-quantitative distributions, presumably apoplast transport patterns for the Gd, Sm and Cd were investigated in the primordial leaf tissues of the bean using dynamic neutron radiography. According to the applied 3D, 2D images and the pixel count distribution histograms of the considered gray levels, peculiar distribution patterns were postulated for the elements. Main and lateral vascular systems for Gd, the cell walls as well as intercellular spaces for Sm and the main leaf vein for Cd assumed to be the apoplast transport spaces and volumes.

  11. Ab initio calculation of the migration free energy of oxygen diffusion in pure and samarium-doped ceria

    Science.gov (United States)

    Koettgen, Julius; Schmidt, Peter C.; Bučko, Tomáš; Martin, Manfred

    2018-01-01

    We have studied the free energy migration barriers Δ F‡ for oxygen diffusion in pure ceria and Sm-doped ceria for the temperatures 300, 700, and 1000 K. We used the density functional theory in the generalized gradient approximation and an additional Hubbard U parameter for the Ce 4 f electronic states. We compare the results for the free energy deduced from three different methods. First, a static harmonic approach is applied in which the temperature dependent vibrational contributions to energy and entropy are deduced from the phonon frequencies of supercells with a fixed volume. Second, a static quasiharmonic approach is used in which a part of the anharmonicity effect is introduced via an implicit dependence of the harmonic frequencies on the thermally expanding cell volume. Third, the free energy barriers are calculated using metadynamics and molecular dynamics in which anharmonicity effects are naturally taken into account. The three methods examined in this study lead to distinctly different results. According to the harmonic approximation, the migration free energy difference Δ F‡ increases with increasing temperature due to an increasing entropic contribution. According to the quasiharmonic approximation, the migration free energy is independent of temperature. Finally, molecular dynamics predicts a thermally induced increase in the migration free energy. We conclude that temperature dependent experimental lattice constants cancel out the increasing entropic contribution with increasing temperature in the static quasiharmonic approach. The full consideration of anharmonicity effects in the metadynamics method again leads to a temperature dependent migration free energy.

  12. Studies on the preparation and stability of samarium-153 propylene diamine tetramethylene phosphonate (PDTMP) complex as a bone seeker

    Energy Technology Data Exchange (ETDEWEB)

    Majali, M.A. E-mail: mythili@magnum.barc.ernet.in; Mathakar, A.R.; Shimpi, H.H.; Banerjee, Sharmila; Samuel, Grace

    2000-12-15

    Propylene diamine tetra methylene phosphonate (PDTMP) was synthesised by modifying a method reported for the synthesis of EDTMP. Complexation of the synthesised phosphonate ligand with {sup 153}Sm was carried out by varying the experimental parameters and the complex was radiochemically characterized. Biodistribution studies showed that the uptake by bone in rats was 2% per g of bone, which was retained up to 48 h. The uptake by other organs was insignificant, except by the liver which showed a slightly higher absorption.

  13. Crystal structure of a samarium(III nitrate chain cross-linked by a bis-carbamoylmethylphosphine oxide ligand

    Directory of Open Access Journals (Sweden)

    Julie A. Stoscup

    2014-10-01

    Full Text Available In the title compound poly[aquabis(μ-nitrato-κ4O,O′:O,O′′tetrakis(nitrato-κ2O,O′{μ4-tetraethyl [(ethane-1,2-diylbis(azanediylbis(2-oxoethane-2,1-diyl]diphosphonate-κ2O,O′}disamarium(III], [Sm2(NO36(C14H30N2O8P2(H2O]n, a 12-coordinate SmIII and a nine-coordinate SmIII cation are alternately linked via shared bis-bidentate nitrate anions into a corrugated chain extending parallel to the a axis. The nine-coordinate SmIII atom of this chain is also chelated by a bidentate, yet flexible, carbamoylmethylphoshine oxide (CMPO ligand and bears one water molecule. This water molecule is hydrogen bonded to nitrate groups bonded to the 12-coordinate SmIII cation. The CMPO ligand, which lies about an inversion center, links neighboring chains along the c axis, forming sheets parallel to the ac plane. Hydrogen bonds between the amide NH group and metal-bound nitrate anions are also present in these sheets. The sheets are packed along the b axis through only van der Waals interactions.

  14. Structure, reactivity, electronic configuration and magnetism of samarium atomic layers deposited on Si(0 0 1) by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Gheorghe, Nicoleta G.; Lungu, George A.; Husanu, Marius A.; Costescu, Ruxandra M.; Macovei, Dan [National Institute of Materials Physics, Atomistilor 105 b, 077125 Magurele-Ilfov (Romania); Teodorescu, Cristian M., E-mail: teodorescu@infim.ro [National Institute of Materials Physics, Atomistilor 105 b, 077125 Magurele-Ilfov (Romania)

    2013-02-15

    The surface structure, interface reactivity, electron configuration and magnetic properties of Sm layers deposited on Si(0 0 1) at various temperatures are investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) and magneto-optical Kerr effect (MOKE). It is found that metal Sm is present on samples prepared at low temperature, with an interface layer containing SmSi{sub 2} and Sm{sub 4}Si{sub 3}. When samples are prepared at high temperature, much less metal Sm is found, with an increasing amount of SmSi{sub 2}. Room temperature ferromagnetism is observed for all prepared layers, with a decrease of the saturation magnetization when samples are prepared at high temperature. It is found that ferromagnetism implies mostly a compound with approximate stoichiometry Sm{sub 4}Si{sub 3}. Also, the decrease in the intensity of the XAS 2p{sub 3/2} → 3d white lines with the corresponding increasing amount of SmSi{sub 2} may be explained by assuming a higher occupancy of Sm 5d orbitals (5d{sup 2} configuration), most probably due to hybridation effects.

  15. Calculation and comparison of xenon and samarium reactivities of the HEU, LEU core in the low power research reactor.

    Science.gov (United States)

    Dawahra, S; Khattab, K; Saba, G

    2015-07-01

    Comparative studies for the conversion of the fuel from HEU to LEU in the Miniature Neutron Source Reactor (MNSR) have been performed using the MCNP4C and GETERA codes. The precise calculations of (135)Xe and (149)Sm concentrations and reactivities were carried out and compared during the MNSR operation time and after shutdown for the existing HEU fuel (UAl4-Al, 90% enriched) and the potential LEU fuels (U3Si2-Al, U3Si-Al, U9Mo-Al, 19.75% enriched and UO2, 12.6% enriched) in this paper using the MCNP4C and GETERA codes. It was found that the (135)Xe and (149)Sm reactivities did not reach their equilibrium reactivities during the daily operating time of the reactor. The (149)Sm reactivities could be neglected compared to (135)Xe reactivities during the reactor operating time and after shutdown. The calculations for the UAl4-Al produced the highest (135)Xe reactivity in all the studied fuel group during the reactor operation (0.39 mk) and after the reactor shutdown (0.735 mk), It followed by U3Si-Al (0.34 mk, 0.653 mk), U3Si2-Al (0.33 mk, 0.634 mk), U9Mo-Al (0.3 mk, 0.568 mk) and UO2 (0.24 mk, 0.448 mk) fuels, respectively. Finally, the results showed that the UO2 was the best candidate for fuel conversion to LEU in the MNSR since it gave the lowest (135)Xe reactivity during the reactor operation and after shutdown. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Development of samarium [{sup 32}P] phosphate colloid for radiosynoviorthesis applications: Preparation, biological and preliminary clinical studies experience

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakar, G. [Radiopharmaceuticals Programme, Board of Radiation and Isotope Technology (BRIT), BARC Vashi Complex, Sector-20, Navi Mumbai 400 705 (India)], E-mail: gantipk47@rediffmail.com; Sachdev, Satbir S.; Umamaheswari, S.; Sivaprasad, N.; Bhatia, Manohar H. [Radiopharmaceuticals Programme, Board of Radiation and Isotope Technology (BRIT), BARC Vashi Complex, Sector-20, Navi Mumbai 400 705 (India); Chaudhari, Pradip R. [Laboratory Nuclear Medicine Services, BARC, Mumbai 400 012 (India); Solav, Srikant V. [Spect Lab, Nuclear Medicine Services, Opposite Dinanath Mangeshkar Hospital, Pune 411004 (India)

    2007-12-15

    A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl{sub 3} carrier with carrier added [{sup 32}P]H{sub 3}PO{sub 4} in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1-10 {mu}m as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation.

  17. The platinum-rich scandium silicide Sc{sub 2}Pt{sub 9}Si{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Vosswinkel, Daniel; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-10-01

    Single crystals of Sc{sub 2}Pt{sub 9}Si{sub 3} have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc{sub 2}Pt{sub 9}Si{sub 3} structure (Tb{sub 2}Pt{sub 9}Ge{sub 3} type, space group C2/c) was refined from single crystal X-ray diffractometer data: a=1303.4(1), b=749.9(1), c=973.5(1), β=116.44(1) {sup circle}, wR2=0.0731, 1643 F{sup 2} values and 67 variables. The structure contains three basic coordination polyhedra Sc rate at Pt{sub 11}, Si1 rate at Pt{sub 8} and Si2 rate at Pt{sub 8} which show a simple condensation pattern avoiding direct Sc-Si and Si-Si bonding.

  18. Thermal transport across metal silicide-silicon interfaces: First-principles calculations and Green's function transport simulations

    Science.gov (United States)

    Sadasivam, Sridhar; Ye, Ning; Feser, Joseph P.; Charles, James; Miao, Kai; Kubis, Tillmann; Fisher, Timothy S.

    2017-02-01

    Heat transfer across metal-semiconductor interfaces involves multiple fundamental transport mechanisms such as elastic and inelastic phonon scattering, and electron-phonon coupling within the metal and across the interface. The relative contributions of these different transport mechanisms to the interface conductance remains unclear in the current literature. In this work, we use a combination of first-principles calculations under the density functional theory framework and heat transport simulations using the atomistic Green's function (AGF) method to quantitatively predict the contribution of the different scattering mechanisms to the thermal interface conductance of epitaxial CoSi2-Si interfaces. An important development in the present work is the direct computation of interfacial bonding from density functional perturbation theory (DFPT) and hence the avoidance of commonly used "mixing rules" to obtain the cross-interface force constants from bulk material force constants. Another important algorithmic development is the integration of the recursive Green's function (RGF) method with Büttiker probe scattering that enables computationally efficient simulations of inelastic phonon scattering and its contribution to the thermal interface conductance. First-principles calculations of electron-phonon coupling reveal that cross-interface energy transfer between metal electrons and atomic vibrations in the semiconductor is mediated by delocalized acoustic phonon modes that extend on both sides of the interface, and phonon modes that are localized inside the semiconductor region of the interface exhibit negligible coupling with electrons in the metal. We also provide a direct comparison between simulation predictions and experimental measurements of thermal interface conductance of epitaxial CoSi2-Si interfaces using the time-domain thermoreflectance technique. Importantly, the experimental results, performed across a wide temperature range, only agree well with predictions that include all transport processes: elastic and inelastic phonon scattering, electron-phonon coupling in the metal, and electron-phonon coupling across the interface.

  19. Tetrakis(μ-propanoato-κ2O:O′bis[(1,10-phenanthroline-κ2N,N′(propanoato-κ2O,O′samarium(III

    Directory of Open Access Journals (Sweden)

    Chun-Xiang Wang

    2008-01-01

    Full Text Available The title complex, [Sm2(C3H5O26(C12H8N22], is a dinuclear centrosymmetric molecule, in which two crystallographically equivalent Sm atoms, separated by 3.9502 (2 Å, are bridged by four propanoate anions. Each Sm atom is coordinated by two N atoms from one chelating phenanthroline ligand and seven carboxylate O atoms from five propanoate anions, to form a distorted tricapped trigonal prism.

  20. Processing of composites based on NiO, samarium-doped ceria and carbonates (NiO-SDCC as anode support for solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Lily Siong Mahmud

    2017-09-01

    Full Text Available NiO-SDCC composites consisting of NiO mixed with Sm-doped ceria (SDC and carbonates (Li2CO3 and Na2CO3 were sintered at different temperatures and reduced at 550 °C. The influence of reduction on structure of the NiO-SDCC anode support for solid oxide fuel cells (SOFCs was investigated. Raman spectra of the NiO-SDCC samples sintered at 500, 600 and 700 °C showed that after reducing at 550 °C NiO was reduced to Ni. In addition, SDC and carbonates (Li2CO3 and Na2CO3 did not undergo chemical transformation after reduction and were still detected in the samples. However, no Raman modes of carbonates were identified in the NiO-SDCC pellet sintered at 1000 °C and reduced at 550 °C. It is suspected that carbonates were decomposed at high sintering temperature and eliminated due to the reaction between the CO32– and hydrogen ions during reduction in humidified gases at 550 °C. The carbonate decomposition increased porosity in the Ni-SDCC pellets and consequently caused formation of brittle and fragile structure unappropriated for SOFC application. Because of that composite NiO-SDC samples without carbonates were also analysed to determine the factors affecting the crack formation. In addition, it was shown that the different reduction temperatures also influenced the microstructure and porosity of the pellets. Thus, it was observed that Ni-SDC pellet reduced at 800 °C has higher electrical conductivity of well-connected microstructures and sufficient porosity than the pellet reduced at 550 °C.

  1. The single cell of low temperature solid oxide fuel cell with sodium carbonate-SDC (samarium-doped ceria) as electrolyte and biodiesel as fuel

    Science.gov (United States)

    Rahmawati, F.; Nuryanto, A.; Nugrahaningtyas, K. D.

    2016-02-01

    In this research NSDC (composite of Na2CO3-SDC) was prepared by the sol-gel method to produce NSDC1 and also by the ceramic method to produce NSDC2. The prepared NSDC then were analyzed by XRD embedded with Le Bail refinement to study the change of characteristic peaks, their crystal structure, and their cell parameters. Meanwhile, the measurement of impedance was conducted to study the electrical conductivity of the prepared materials. A single cell was prepared by coating NSDC-L (a composite of NSDC with Li0.2Ni0.7Cu0.1O2) on both surfaces of NSDC. The NSDC-L was used as anode and cathode. The ionic conductivity of NSDC1 and NSDC2 at 400 oC are 4.1109 x 10-2 S.cm-1 and 1.6231 x 10-2 S.cm-1, respectively. Both electrolytes have ionic conductivity higher than 1 x 10-4 S.cm-1, therefore, can be categorized as good electrolyte [1]. However, the NSDC1 shows electrodeelectrolyte conduction. It indicates the existence of electronic migration from electrolyte- electrode or vice versa. Those may cause a short circuit during fuel cell operation and will reduce the fuel cell performance fastly. The single cell tests were conducted at 300, 400, 500 and 600 °C. The single fuel cell with NSDC1 and NSDC2 as electrolyte show maximum power density at 400 °C with the power density of 3.736 x 10-2 mW.cm-2 and 2.245 x 10-2 mW.cm-2, respectively.

  2. Samarium-neodymium chronology and rubidium-strontium systematics of an Allende calcium-aluminum-rich inclusion with implications for 146Sm half-life

    Science.gov (United States)

    Marks, N. E.; Borg, L. E.; Hutcheon, I. D.; Jacobsen, B.; Clayton, R. N.

    2014-11-01

    Calcium-aluminum-rich inclusions (CAIs) are primitive objects that formed within the protoplanetary disk surrounding the young Sun. Recent Pb-Pb chronologic studies have demonstrated that CAIs are the oldest solar system solids, crystallizing 4567 Ma ago (Amelin et al., 2002; Connelly et al., 2012). The isotope systematics of CAIs therefore provide critical insight into the earliest history of the Solar System. Although Sm-Nd and Rb-Sr geochronometers are highly effective tools for investigating cosmochemical evolution in the early Solar System, previous studies of CAIs have revealed evidence for isotopically disturbed systems. Here we report new age data for Allende CAI Al3S4 derived from both the long-lived (147Sm-143Nd) and short-lived (146Sm-142Nd) isotopic systems. The 147Sm-143Nd chronometer yields an age of 4560 ± 34 Ma that is concordant with 207Pb-206Pb ages for CAIs and indicates that the Sm-Nd system was not significantly disturbed by secondary alteration or nucleosynthetic processes. The slope of the 146Sm-142Nd isochron defines the Solar System initial 146Sm/144Sm of 0.00828 ± 0.00044. This value is significantly different from the value of 0.0094 determined by Kinoshita et al. (2012). Ages recalculated from all published 146Sm-142Nd isochron data using the traditional 103 Ma half-life and the initial 146Sm/144Sm value determined here closely match Pb-Pb and 147Sm-143Nd ages determined on the same samples. In contrast, ages recalculated using the 68 Ma half-life determined by Kinoshita et al. (2012) and either of the initial 146Sm/144Sm values are often anomalously old. This is particularly true for the youngest samples with 146Sm-142Nd isochron ages that are most sensitive to the choice of 146Sm half-life used in the age calculation. In contrast to the Sm-Nd isotope system, the Rb-Sr system is affected by alteration but yields an apparent isochron with a slope corresponding to a much younger age of 4247 ± 110 Ma. Although the Rb-Sr system in CAIs appears to be disturbed, the initial 87Sr/86Sr value determined from the isochron is 0.698942 ± 0.000008, and closely approximates estimates of the initial Solar System value. Although this isochron may be a mixing line, it might also record alteration on the Allende parent body in which Rb was added to the Al3S4 CAI that was initially largely devoid of Rb.

  3. Anthropogenic dissolved and colloid/nanoparticle-bound samarium, lanthanum and gadolinium in the Rhine River and the impending destruction of the natural rare earth element distribution in rivers

    Science.gov (United States)

    Kulaksız, Serkan; Bau, Michael

    2013-01-01

    The strong increase in the consumption of rare earth elements (REE) in high-tech products and processes is accompanied by increasing amounts of REE released into the environment. Following the first report of Gd contamination of the hydrosphere in 1996, anthropogenic Gd originating from contrast agents has now been reported worldwide from river and estuarine waters, coastal seawater, groundwater and tap water. Recently, microcontamination with La, that is derived from a point source where catalysts for petroleum refining are produced, has been detected in the Rhine River in Germany and the Netherlands. Here we report the occurrence of yet another REE microcontamination of river water: in addition to anthropogenic Gd and La, the Rhine River now also shows significant amounts of anthropogenic Sm. The anthropogenic Sm, which enters the Rhine River north of Worms, Germany, with the same industrial wastewater that carries the anthropogenic La, can be traced through the Middle and Lower Rhine to the Netherlands. At Leverkusen, Germany, some 250 km downstream from the point source at Worms, anthropogenic Sm still contributes up to 87% of the total dissolved Sm concentration of the Rhine River. Results from ultrafiltration suggest that while the anthropogenic Gd is not particle-reactive and hence exclusively present in the truly dissolved REE pool (Worms get close to and well-above, respectively, the levels at which ecotoxicological effects have been documented. Because of the increasing use of REE and other formerly "exotic" trace elements in high-tech applications, these critical metals have now become emerging contaminants that should be monitored, and it appears that studies of their biogeochemical behavior in natural freshwaters might soon no longer be possible.

  4. Ultra-Sensitive Nano Optical Sensor Samarium-Doxycycline Doped in Sol Gel Matrix for Assessment of Glucose Oxidase Activity in Diabetics Disease.

    Science.gov (United States)

    Tharwat, Marwa M; Attia, M S; Alghamdi, M S; Mahros, Amr M

    2017-07-11

    A low cost and very sensitive method for the determination of the activity of glucose oxidase enzyme in different diabetics serum samples was developed. The method based on the assessment of the H2O2 concentration produced from the reaction of the glucose oxidase (GOx) enzyme with glucose as substrate in the serum of diabetics patients by nano optical sensor Sm-doxycycline doped in sol gel matrix. H2O2 enhances the luminescence intensity of all bands of the nano Sm-doxycycline complex [Sm-(DC)2](+) doped in sol-gel matrix, especially the 645 nm band at λex = 400 nm and pH 7.0 in water. The influence of the different analytical parameters that affect the luminescence intensity of the nano optical sensor, e.g. pH, H2O2 concentration and foreign ions concentrations were studied. The remarkable enhancement of the luminescence intensity of nano optical sensor [Sm-(DC)2](+) complex in water at 645 nm by the addition of various concentrations of H2O2 was successfully used as an optical sensor for the assessment of the activity of the glucose oxidase enzyme in different diabetics serum samples. The calibration plot was achieved over the activity range 0.1-240 U/L with a correlation coefficient of 0.999 and a detection limit of 0.05 U/L.

  5. Effect of Mg doping and sintering temperature on structural and morphological properties of samarium-doped ceria for IT-SOFC electrolyte

    Science.gov (United States)

    Ahmad, Syed Ismail; Mohammed, Tasneem; Bahafi, Amal; Suresh, Madireddy Buchi

    2017-06-01

    Samples of Sm and Mg co-doped ceria electrolyte of Ce1- x Sm x- y Mg y O2- δ ( x = 0.2; y = 0.00, 0.05, 0.1, 0.15, and 0.175) were synthesized by sol-gel process. The prepared samples were sintered at 1100 and 1400 °C for 4 h. The bulk densities were measured by Archimedes method. XRD measurements indicate that the synthesized samples were in single-phase cubic fluorite structure (space group Fm3m). The cell parameters decrease with the concentration of Mg, and 2 θ values slightly shift towards right. The particle sizes obtained were between 7.14 and 17.44 nm. The sintered sample achieved 95% of theoretical density. FTIR spectra of samples sintered at 1400 °C indicates weak interactions between 3550-3400 cm-1 and 1600-1300 cm-1 are attributed to O-H stretching modes and strong bonds 850-450 cm-1 are assigned to characteristic Ce-O vibrations. The surface morphology and chemical composition were analyzed by SEM and EDS, SEM micrographs show spherical faceted grains, and the samples were crack free, dense material with some pores on surface which are inconsistent with density results. The average grain size obtained was 0.5 μm. Particle size obtained by TEM was in agreement with that obtained by XRD. The high-density ceria co-doped ceramic can be used as electrolyte in SOFC.

  6. Synthesis, spectroscopic, thermal and antimicrobial studies of neodymium(III) and samarium(III) complexes derived from tetradentate ligands containing N and S donor atoms

    Science.gov (United States)

    Ain, Qurratul; Pandey, S. K.; Pandey, O. P.; Sengupta, S. K.

    2015-04-01

    Trivalent lanthanide complexes of the type [Ln(L)Cl(H2O)2] (where Ln = Nd(III) or Sm(III) and LH2 = Schiff bases derived by the condensation of 3-(phenyl/substitutedphenyl)-4-amino-5-mercapto-1,2,4-triazole with diacetyl/benzil) have been synthesized by the reactions of anhydrous lanthanide(III) chloride with Schiff bases in methanol. The structures of the complexes have been proposed on the basis of elemental analysis, electrical conductance, magnetic moment, spectroscopic measurements (IR, 1H, 13C NMR and UV-vis spectra) and X-ray diffraction studies. The spectral data reveal that the Schiff base ligands behave as dibasic tetradentate chelating agents having coordination sites at two thiol sulfur atoms and two azomethine nitrogen atoms. The presence of coordinated water in metal complexes was confirmed by thermal and IR data of the complexes. All the Schiff bases and their metal complexes have also been screened for their antibacterial activity against Bacillus subtilis, Staphylococcus aureus and antifungal activities against Aspergillus niger, Curvularia pallescens and Colletotrichum capsici.

  7. Logarithmic temperature dependence of samarium ion valence in the heavy-fermion S mxL a1 -xO s4S b12

    Science.gov (United States)

    Fushiya, Kengo; Miyazaki, Ryoichi; Higashinaka, Ryuji; Yamada, Akira; Mizumaki, Masaichiro; Tsutsui, Satoshi; Nitta, Kiyofumi; Uruga, Tomoya; Suemitsu, Bunya; Sato, Hideyuki; Aoki, Yuji

    2015-08-01

    We have measured x-ray absorption spectra at the Sm L3 edge to investigate the Sm-ion valence of (S mxL a1 -x) O s4S b12 , in which field-insensitive heavy-fermion behavior appears at low temperatures for x =1 . It has been found that the Sm-ion valance shifts to 2 + with La ion substitution; from v =+2.78 (x =1 ) to v =+2.73 (x =0.2 ) at 10 K. For all x investigated, its temperature dependence shows a logT behavior, indicating that the valence change is caused by "an unconventional Kondo effect" associated with Sm 4 f -electron charge degrees of freedom. Almost x independence of "the associated Kondo temperature" (T˜K=56 ±10 K ) indicates that the Kondo effect has a local nature, attributable to the cage structure of the filled skutterudite.

  8. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water

    Energy Technology Data Exchange (ETDEWEB)

    Merschel, Gila, E-mail: g.merschel@jacobs-university.de; Bau, Michael

    2015-11-15

    High-technology metals — such as the rare earth elements (REE) — have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. - Highlights: • Corbicula fluminea shells are bioarchives of dissolved geogenic REE in rivers. • Anthropogenic La and Sm in the Rhine River are bioavailable, hence incorporated. • Anthropogenic Gd from contrast agents is not incorporated, i.e. not bioavailable. • REE concentrations in Corbicula shells decrease with increasing size, i.e. age.

  9. Mechanically induced strong red emission in samarium ions doped piezoelectric semiconductor CaZnOS for dynamic pressure sensing and imaging

    Science.gov (United States)

    Wang, Wei; Peng, Dengfeng; Zhang, Hanlu; Yang, Xiaohong; Pan, Caofeng

    2017-07-01

    Piezoelectric semiconductor with optical, electrical and mechanical multifunctions has great potential applications in future optoelectronic devices. The rich properties and applications mainly encompass the intrinsic structures and their coupling effects. Here, we report that lanthanide ions doped piezoelectric semiconductor CaZnOS:Sm3+ showing strong red emission induced by dynamic mechanical stress. Under moderate mechanical load, the doped piezoelectric semiconductor exhibits strong visible red emission to the naked eyes even under the day light. A flexible dynamic pressure sensor device is fabricated based on the prepared CaZnOS:Sm3+ powders. The mechanical-induced emission properties of the device are investigated by the optical fiber spectrometer. The linear characteristic emissions are attributed to the 4G5/2→6H5/2 (566 nm), 4G5/2→6H7/2 (580-632 nm), 4G5/2→6H9/2 (653-673 nm) and 4G5/2→6H11/2 (712-735 nm) f-f transitions of Sm3+ ions. The integral emission intensity is proportional to the value of applied pressure. By using the linear relationship between integrated emission intensity and the dynamic pressure, the real-time pressure distribution is visualized and recorded. Our results highlight that the incorporation of lanthanide luminescent ions into piezoelectric semiconductors as smart materials could be applied into the flexible mechanical-optical sensor device without additional auxiliary power, which has great potential for promising applications such as mapping of personalized handwriting, smart display, and human machine interface.

  10. Investigation of oxidative coupling of methane over bismuth oxychloride, samarium chloride, or manganese chloride supported on lithium carbonate-magnesia systems

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A.Z.; Ruckenstein, E. (State Univ. of New York, Buffalo, NY (United States))

    1992-11-01

    The magnesia-supported bismuth oxychloride with lithium carbonate present is significantly more effective and stable with time-on-stream than the unsupported or supported systems free of Li[sub 2]CO[sub 3] in the oxidative coupling of methane at 750[degrees]C, P[sub CH[sub 4

  11. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

    Science.gov (United States)

    Merschel, Gila; Bau, Michael

    2015-11-15

    High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Samario-153-Lexidronam (EDTMP) en el tratamiento de las metástasis óseas Samarium-153-Lexidronam (EDTMP) for the management of bone metastases

    OpenAIRE

    F. Torre; C. Gómez-Vega; A. Callejo; J. Genolla

    2004-01-01

    Las metástasis óseas son una complicación frecuente en pacientes neoplásicos, en este sentido, el tejido óseo ocupa el tercer lugar de todos los órganos y sistemas con metástasis después del pulmón e hígado. Aproximadamente un 75% de los enfermos con metástasis óseas sufrirán dolor, siendo estas la causa más frecuente de dolor en pacientes con cáncer. El dolor óseo aumenta con los movimientos y a la presión, limitando la autonomía del enfermo y su calidad de vida. El tratamiento incluye vario...

  13. Morphology and orientation of β-BaB{sub 2}O{sub 4} crystals patterned by laser in the inside of samarium barium borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Nishii, Akihito; Shinozaki, Kenji; Honma, Tsuyoshi; Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.jp

    2015-01-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystal lines (β-BBO) were patterned in the inside of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by irradiations of continuous-wave Yb:YVO{sub 4} lasers with a wavelength of 1080 nm (power: P=0.8–1.0 W, scanning speed: S=0.2–2.5 μm/s), in which the laser focal position was moved gradually from the surface to the inside. The morphology, size, and orientation of β-BBO crystals were examined from polarization optical microscope and birefringence imaging observations. It was demonstrated that c-axis oriented β-BBO crystals with long lengths (e.g., 20 mm) were patterned in the inside of the glass. The morphology of β-BBO in the cross-section of lines was a rectangular shape with rounded corners, and the volume of β-BBO formed increased with increasing laser power and with decreasing laser scanning speed. The maximum depth in the inside from the surface for β-BBO patterning increased with increasing laser power, e.g., D{sub max}∼100 μm at P=0.8 W, D{sub max}∼170 μm at P=0.9 W, and D{sub max}∼200 μm at P=1 W. The present study proposes that the laser-induced crystallization opens a new door for applied engineering in glassy solids. - Graphical abstract: This figure shows the POM photographs for β-BaB{sub 2}O{sub 4} crystal lines patterned by cw Yb:YVO{sub 4} fiber laser irradiations with a laser power of P=0.8 W and a laser scanning speed S=2 μm/s in the glass. The laser focal point was moved gradually from the surface into the inside. The results shown in Fig. 1 demonstrate that it is possible to pattern highly oriented β-BaB{sub 2}O{sub 4} crystals even in the inside of glasses. - Highlights: • β-BaB{sub 2}O{sub 4} crystal lines were patterned in the inside of a glass by lasers. • Laser focal position was moved gradually from the surface to the inside. • Birefringence imaging was observed. • Morphology, size, and orientation of crystals were clarified. • Crystal lines with long lengths (e.g., 20 mm) were patterned at the depth of 200 μm.

  14. 10 CFR Appendix C to Part 20 - Quantities 1 of Licensed Material Requiring Labeling

    Science.gov (United States)

    2010-01-01

    ... Samarium-151 10 Samarium-153 100 Samarium-155 1,000 Samarium-156 1,000 Europium-145 100 Europium-146 100 Europium-147 100 Europium-148 10 Europium-149 100 Europium-150 (12.62h) 100 Europium-150 (34.2y) 1 Europium-152m 100 Europium-152 1 Europium-154 1 Europium-155 10 Europium-156 100 Europium-157 100 Europium-158 1...

  15. An experiment using neutron activation analysis and a rare earth element to mark cotton plants and two insects that feed on them

    Energy Technology Data Exchange (ETDEWEB)

    Showler, Allan T. [USDA-ARS IFNRRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States)]. E-mail: ashowler@weslaco.ars.usda.gov; James, William D. [Elemental Analysis Laboratory, 3144 Texas A and M University, College Station, TX 77843-3144 (United States); Armstrong, John S. [USDA-ARS BIRU, Kika de la Garza Subtropical Agricultural Research Center, 2413 East Highway 83, Weslaco, TX 78596 (United States); Westbrook, John K. [USDA-ARS APMRU, 2771 F and B Road, College Station, TX 77845-4966 (United States)

    2006-08-15

    Studies on insect dispersal and other behaviors can benefit from using markers that will not alter flight and fitness. Rare earth elements, such as samarium (Sm), have been used as ingested markers of some insects and detected using neutron activation analysis (NAA). In this study, samarium nitrate hexahydrate was mixed into artificial diet for boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), at different dosages and in water used to irrigate cotton, Gossypium hirsutum L. Samarium was detected in adult boll weevils fed on the samarium-labeled diet, but not after 5 or 10 days of being switched to non-labeled diet, even if the insects were given labeled diet for as long as 7 consecutive days. Introduced in irrigation water, 1% samarium (m/m) was detectable in cotton squares and leaf tissue. However, boll weevil adults fed samarium-labeled squares did not retain detectable levels of samarium, nor did boll weevil adults reared to adulthood from samarium-labeled squares. Fourth instar beet armyworms, Spodoptera exigua (Huebner) (Noctuidae: Lepidoptera), fed on samarium-labeled cotton leaves obtained enough samarium for NAA detection, but adult moths reared from them did not have detectable amounts of samarium. Although samarium can be useful as a marker when insects are presented with a continuous pulse of the label, elements that are assimilated by the insect would be more useful if a continuous infusion of the marker cannot be provided.

  16. Iron silicide formation at different layers of (Fe/Si){sub 3} multilayered structures determined by conversion electron Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Badía-Romano, L., E-mail: lbadia@unizar.es; Bartolomé, J. [Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50009 Zaragoza (Spain); Rubín, J. [Departamento de Ciencia y Tecnología de Materiales y Fluidos, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, E-50018 Zaragoza (Spain); Magén, C. [Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, E-50018 Zaragoza (Spain); Bürgler, D. E. [Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany)

    2014-07-14

    The morphology and the quantitative composition of the Fe-Si interface layer forming at each Fe layer of a (Fe/Si){sub 3} multilayer have been determined by means of conversion electron Mössbauer spectroscopy (CEMS) and high-resolution transmission electron microscopy (HRTEM). For the CEMS measurements, each layer was selected by depositing the Mössbauer active {sup 57}Fe isotope with 95% enrichment. Samples with Fe layers of nominal thickness d{sub Fe} = 2.6 nm and Si spacers of d{sub Si} = 1.5 nm were prepared by thermal evaporation onto a GaAs(001) substrate with an intermediate Ag(001) buffer layer. HRTEM images showed that Si layers grow amorphous and the epitaxial growth of the Fe is good only for the first deposited layer. The CEMS spectra show that at all Fe/Si and Si/Fe interfaces a paramagnetic c-Fe{sub 1−x}Si phase is formed, which contains 16% of the nominal Fe deposited in the Fe layer. The bottom Fe layer, which is in contact with the Ag buffer, also contains α-Fe and an Fe{sub 1−x}Si{sub x} alloy that cannot be attributed to a single phase. In contrast, the other two layers only comprise an Fe{sub 1−x}Si{sub x} alloy with a Si concentration of ≃0.15, but no α-Fe.

  17. Interaction mechanism between niobium-silicide-based alloy melt and Y2O3 refractory crucible in vacuum induction melting process

    Directory of Open Access Journals (Sweden)

    Gao Ming

    2011-05-01

    Full Text Available The Y2O3 crucibles were introduced in the study as an alternative to the traditional ceramic ones in vacuum induction melting of multi-component Nb-16Si-22Ti-2Al-2Hf-17Cr (at.% alloys, to reveal the possible interactions between the alloy melt and the refractory crucible. Multiple melting time lengths and two cooling schemes were designed and used for the experiments. The chemical composition and microstructure of the tested alloy and the melt-crucible interaction were investigated and evaluated. In the experiments, Y2O3 crucible displays good physical-chemical compatibility. The results indicate that the increment of O element in the as-cast ingot is 0.03at.%-0.04at.% (72-97 ppm and the increment of Y element is very insignificant. The key features of the alloy melt interacting with Y2O3 ceramics are analyzed and concluded in the paper. As a result of the dissolution reaction xY2O3 (in molten alloy + (1-xHfO2 (impurity →Hf1-xY2xO2-x, a continuous double-layer solid film consisted of HfO2 solid solution (~2 μm and pure HfO2 (~5 μm is formed on the surface of the test ingot after cooled down in the crucible. The experimental results show that the Y2O3 crucible is applicable to the vacuum induction melting of Nb-Si based alloys.

  18. Oxide meets silicide. Synthesis and single-crystal structure of Ca{sub 21}SrSi{sub 24}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reckeweg, Olaf; DiSalvo, Francis J. [Cornell Univ., Ithaca, NY (United States). Dept. of Chemistry and Chemical Biology

    2017-06-01

    A few black, rectangular thin plates of Ca{sub 21}SrSi{sub 24}O{sub 2} were obtained by serendipity in a solid-state reaction of calcium metal, strontium chloride and silicon powder at 1200 K for 2 days designed to produce 'Ca{sub 2}SrCl{sub 2}[Si{sub 3}]'. The title compound forms next to some CaSi and some remaining educts. Ca{sub 21}SrSi{sub 24}O{sub 2} crystallizes in the monoclinic space group C2/m (no. 12) with unit cell parameters of a=1895.2(2), b=450.63(5) and c=1397.33(18) pm and β=112.008(7) (Z=1). The title compound shows planar, eight-membered, kinked Si{sub 8} chains with Si-Si distances between 241.4 and 245.0 pm indicating bonding interactions and kinked 'rope ladders' connecting the chains with interatomic Si-Si distances in the range 268.1-274.7 pm. Embedded in between these silicon substructures are columns of oxygen centered, apex sharing [(Ca{sub 1-x} Sr{sub x}){sub 6/2}O] octahedra and calcium ions.

  19. Current–voltage studies on β-FeSi2/Si heterojunction

    Indian Academy of Sciences (India)

    later treated by pulsed laser. Temperature of thermal annealing and diode area ... Silicide; semiconducting silicide; heterojunction; pulsed laser; I–V characteristics. 1. Introduction β-FeSi2 is a semiconducting silicide .... region and the electric field due to ionized impurities in Si yields a current in the opposite direction to that ...

  20. Obtention of Samarium and Gadolinium concentrates by solvent extraction using mono-2-ethylhexyl ester of 2-ethylhexyl phosphonic acid; Obtencao de concentrados de samario e gadolinio via extracao por solventes com o ester mono-2-etilhexil do acido 2-etilhexilfosfonico

    Energy Technology Data Exchange (ETDEWEB)

    Miranda Junior, Pedro

    1996-07-01

    The rare earth chlorides solution employed in this study, which is constituted by medium and heavy fractions, is derived from monazite processing accomplished by NUCLEMON-Mineroquimica (SP). This solution shows an acidity about 1.18 M and 189 g/L of rare earth oxides, containing as main constituents: Sm(34.55%), Gd(23.85%), Dy (6.82%), and Y (24.45%). It was used, as organic phase, 2-ethylhexyl phosphonic acid, mono-2-ethylhexylester diluted to 1 M in isododecane. (author)

  1. Poly(dl)lactic acid/polyglycolic acid/iron and poly(dl)lactic acid/polyglycolic acid/samarium cobalt composites for use as a delivery mechanism for magnetically directed chondrogenesis

    Science.gov (United States)

    Oppermann, Dean Alan

    Magnetically directed chondrogenesis (MDC) is a fundamental approach to articular cartilage repair. In MDC a magnet is implanted into the subchondral trabecular bone underlying a cartilage defect and used to attract chondrocytes, magnetically tagged with Fe nanoparticles, to the defect site. Pilot studies by Halpern, Crimp and Grande, using solid neodymium (Nd) magnets, indicated optimistic results by producing a hyaline-like articular cartilage after 8 weeks implantation. Since solid Nd magnets introduce long-term biocompatibility issues, the focus of this dissertation was to develop P(dl)A/PGA/Fe and P(dl)A/PGA/SmCo 5 implants for use in MDC. The effect of implant porosity, implant composition and magnetic material (Fe or SmCo5) on the initial and degraded magnetic properties were evaluated. The biocompatibility of P(dl)A/PGA/Fe implants were investigated by implantation into New Zealand white rabbits for 8 weeks. The effect of hydrogen peroxide (H2O2) and ethylene oxide (EO) sterilization techniques on the molecular weight and chemical structure of P(dl)A/PGA polymers were evaluated using gel permeation chromatography and Fourier transform infrared spectroscopy. The effect of implant morphology, size and number on the von Mises stress in the trabecular bone surrounding the implant was evaluated using a finite element model. In general, SmCo5 implants resulted in higher magnetic fields initially and after 8 weeks of degradation than comparable Fe implants. Increases in magnetic field strength were achieved by increasing the volume fraction of magnetic material and by increasing the PGA concentration. The magnetic field strength degradation rate decreased with increases in volume fraction of magnetic material and increases in PLA concentration. Implantation studies indicated that 50/50 P(dl)A/PGA were more bioactive than 75/25 P(dl)A/PGA with an increased cellular response that is specific to bone growth. The compressive strength and elastic modulus of porous implants were comparable to trabecular bone, and the compressive strength and elastic modulus of solid implants was higher than trabecular bone but less than cortical bone. Finite element modeling showed that the implantation of solid and porous P(dl)A/PGA/Fe implants did not significantly increase the von Mises stress concentration adjacent to the implant. The von Mises stress surrounding porous implants was higher than the solid implants which predicts faster bone remodeling. Comparing single implants to multiple implants indicated a significant decrease in von Mises stress between the implants. This would predict bone resorption in that area. H2O2 sterilization resulted in a gradual decrease in the molecular weight of P(dl)A/PGA polymers that was a result of hydrolytic scission of the ester bonds present between the individual monomers. The polymers were less affected by EO sterilization with only the 75/25 P(dl)A/PGA, indicating a decrease in molecular weight. From these results, it was concluded that solid 50/50 P(dl)A/PGA/SmCo 5 implants that span the entire width of the cartilage defect should be used to optimize the attraction potential and bioactivity of the implant. Also ethylene oxide, which caused less premature implant degradation, should be used for sterilization.

  2. Fabrication of a new samarium(III) ion-selective electrode based on 3-{l_brace}[2-oxo-1(2h)-acenaphthylenyliden]amino{r_brace}-2-thioxo -1,3-thiazolidin-4-one

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Hassan Ali [Islamic Azad University, Quchan (Iran, islamic Republic of). Quchan Branch. Dept. of Chemistry]. E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza [Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of). Endocrine and Metabolism Research Center; Adib, Mehdi [University of Tehran, Tehran (Iran, Islamic Republic of). Faculty of Chemistry. Center of Excellence in Electrochemistry

    2007-07-01

    This paper introduces the development of an original PVC membrane electrode, based on 3-{l_brace}[2-oxo-1(2H)-acenaphthylenyliden]amino{r_brace}-2-thioxo-1,3-thiazolidin-4-one (ATTO) which has revealed to be a suitable carrier for Sm{sup 3+} ions. The resulting data illustrated that the electrode shows a Nernstian slope of 19.3 {+-} 0.6 mV per decade for Sm{sup 3+} ions over a broad working concentration range of 1.0 X 10{sup -6} to 1.0 X 10{sup -1} mol L{sup -1}. The lower detection limit was found to be equal to (5.5{+-} 0.3) X 10{sup -7} mol L{sup -}'1 in the pH range of 3.5-7.5, and the response time was very short ({approx}10 s). The potentiometric sensor displayed good selectivities for a number of cations such as alkali, alkaline earth, transition and heavy metal ions. (author)

  3. BASIC RESEARCH ON THE SEPARATION OF SCANDIUM YTTRIUM, AND THE RARE EARTHS BY SOLVENT EXTRACTION.

    Science.gov (United States)

    RARE EARTH ELEMENTS, * SOLVENT EXTRACTION ), (*CHELATE COMPOUNDS, RARE EARTH ELEMENTS), PURIFICATION, ATOMIC SPECTROSCOPY, SCANDIUM, YTTRIUM, PRASEODYMIUM, SAMARIUM, EUROPIUM, GADOLINIUM, TERBIUM, FLUORINE COMPOUNDS, KETONES

  4. FY 1998 annual report on the improvement of toughness of silicide-based intermetallic compounds by controlling their composite structures; 1998 nendo fukugo soshikika ni yoru shirisaidokei kinzokukan kagobutsu no kyojinsei kaizen chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Intermetallic compounds, although attracting much attention as most promising materials serviceable at superhigh temperature, are very fragile at normal temperature, which is one of their major disadvantages. Structures of these compounds prepared by the melting method are controlled to improve their toughness by, e.g., changing phase ratio of the initial crystal for the Mo-Si-Nb system to prevent cracking during the melting and casting stages, addition of a third element (e.g., Zr, Ti or Hf) or a mixed component of Nb and Zr to control the structure of Mo{sub 5}Si{sub 3} considered to be a cause for the cracking, and controlling melting and solidification rates for the FZ melting method. The three-phase microstructures with added Hf or Zr show improved toughness, but need additional procedures for controlling solidification and cooling conditions. For the powder method, the MA conditions are investigated with a two-element system, and the effects of Al or Zr as the third element added to the base composition on the composite microstructures and constituent phases are also investigated. Unlike the melting method, the powder method causes no cracking problems during the stock preparation stage and hence is expected to be applicable to production of larger stocks. However, the products by this method are found to be insufficient both in toughness and high-temperature strength. It is necessary to develop methods for cutting down and controlling oxides in the grain boundaries, in order to prevent deterioration of their strength at high temperature. (NEDO)

  5. Assessment of Non-Traditional Isotopic Ratios by Mass Spectrometry for Analysis of Nuclear Activities

    Science.gov (United States)

    2016-03-01

    distinguish between commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium , and products from nuclear weapons explosions. Methods will...Isotopic ratios will be calculated for radionuclides produced in commercial nuclear reactor fuel cycles, fuel cycles for weapons grade plutonium , and... chemistry for analysis of samarium. The chemical form of samarium required for analysis varies for different mass spectrometry techniques

  6. Thermophysical Properties of Matter - the TPRC Data Series. Volume 5. Specific Heat - Nonmetallic Solids

    Science.gov (United States)

    1970-01-01

    Chlorotrifluoromethane (see Freon 13) comide) Chloroform (CHC13) 6 166 Chromium silicides: Chloromethane (see Methyl chloride) CrSi 5 565 Chromel A (see Nichrome...V) CrS 2 5 568 Chromel P 4 392 Cr3Si 5 559 Chromium 4 44 Cr 5 Si 3 5 562 Chromium + Aluninum 4 304 Chromium silicide ( CrSi ) 5 565 Chronium i

  7. Page 1 a i. Bull. Mater. Sci., Vol. 22, No. 3, May 1999, pp. 391-397 ...

    Indian Academy of Sciences (India)

    the amorphous layer. As a result, the average grain size of C49-TiSi, is smaller which leads to lower C49- to C54-TiSi, transformation temperature. Keywords. TiSi; stress; high temperature sputtering. 1. Introduction. For self-aligned silicidation process silicides are formed on source, drain and gate regions simultaneously to ...

  8. The Critical Technologies Project Executive Summary

    Science.gov (United States)

    1981-01-01

    Materials with the Not covered Chalcopyrite Structure 7.8.23 Rare Earth- Transition Metal Permanent Not covered I Magnets (exanple: samarium cobalt and... Transition Metal Permanent - Magnets (example: samarium cobalt I and substituted samarium cobalt) New 7.8.24 Gadolinium Gallium Garnet (GGG) - - and...III T i mm~ 1.W 8 Chwn..cal Poesse Maclw Tools 1110 1129. 1131 133 1142 0 F -~, oO 16.qm P c Metals 1145, 1203, 1236 4203 1365 00, awm.wq *4 1303 1311

  9. sup 8 sup 9 Sr and sup 1 sup 5 sup 3 Sm-EDTMP therapy of disseminated skeletal metastasis

    CERN Document Server

    Zhang Jun Ning; Zhu Shou Peng

    2001-01-01

    A retrospective analysis was performed on 72 patients with disseminated skeletal metastasis to evaluate the effect of strontium-89 or samarium-153 EDTMP therapy. There existed 87.88% of clinical response, 12.12% of no response in the group treated with strontium-89 as compared with 90.24% of clinical response, 9.76% no response in one treated with samarium-153 EDTMP; and there were no correlation between the treatment results and the amounts of isotopes administrated. The results suggest that strontium-89 or samarium-153 EDTMP therapy is a method of first choice in the palliative treatment for disseminated skeletal metastasis

  10. General Information about Osteosarcoma and Malignant Fibrous Histiocytoma of Bone

    Science.gov (United States)

    ... providers who are experts in treating cancer in children. Treatment for osteosarcoma or malignant fibrous histiocytoma may cause side effects. Four types of standard treatment are used: Surgery Chemotherapy Radiation therapy Samarium New types of treatment are ...

  11. Treatment Option Overview (Osteosarcoma and Malignant Fibrous Histiocytoma of Bone)

    Science.gov (United States)

    ... providers who are experts in treating cancer in children. Treatment for osteosarcoma or malignant fibrous histiocytoma may cause side effects. Four types of standard treatment are used: Surgery Chemotherapy Radiation therapy Samarium New types of treatment are ...

  12. Maximum Permissible Concentrations and Negligible Concentrations for Rare Earth Elements (REEs)

    NARCIS (Netherlands)

    Sneller FEC; Kalf DF; Weltje L; Wezel AP van; CSR

    2000-01-01

    In dit rapport worden maximaal toelaatbare risiconiveaus (MTR) en verwaarloosbare risiconiveaus (VR) afgeleid voor zeldzame aardmetalen (ZAM). De geselecteerde ZAMs zijn Yttrium (Y), Lanthanum (La), Cerium (Ce), Praseodymium (Pr), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), en Dysprosium

  13. Bulletin of the Chemical Society of Ethiopia - Vol 31, No 3 (2017)

    African Journals Online (AJOL)

    A novel samarium complex with interesting photoluminescence and semiconductive properties · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. D. W. Zhang, W. T. Chen, Y. F.Wang, 435-444 ...

  14. Influence of P and As implantation of the formation of MoSi2

    Science.gov (United States)

    van Ommen, A. H.; Wolters, R. A. M.

    1985-12-01

    Molybdenum disilicide films have been formed by a reaction of Mo with polycrystalline silicon. Implantation of phosphorus or arsenic prior to reaction has been shown to have a large effect on the silicidation process. The object of implantation was to enhance the silicide reaction by creating damage at the metal-silicon interface. This, then, results in silicide films with less surface roughness (and a lower electrical resistivity). Molecular P+2 ions were found to be more effective in creating damage than single P+ ions, due to the fact that for P+2 ions two simultaneous collision cascades occur which overlap. Apart from the beneficial effect of implantation damage, the introduction of phosphorus has a deleterious effect on the properties of the silicide films. This phenomenon is explained by the presence of a thin and nonuniform native oxide layer which hinders the silicide reaction. Without addition of phosphorus, new nuclei for the silicide reaction can be formed due to stress introduced by the formation of the silicide, which will act upon the oxide and cause it to break up at some weak spot. The effect of phosphorus is proposed to be that it renders the oxide more viscous which prevents this process from taking place. The x-ray diffraction spectra revealed that the orientation of the grains in the polycrystalline MoSi2 films is influenced by the method of preparation.

  15. Specialty Metals: DOD Dissemination of National Security Waiver Information Could Enhance Awareness and Compliance with Restrictions

    Science.gov (United States)

    2014-10-01

    Restrictions Why GAO Did This Study Specialty metals—such as titanium, certain steel alloys , and samarium- cobalt alloy magnets—are essential to DOD...highly magnetic, lightweight, corrosion resistant, or having high durability. Among these metals are samarium- cobalt alloy magnets used to make radar...the following elements: aluminum, chromium , cobalt , columbium, molybdenum, nickel, titanium, tungsten, or vanadium. Specialty metals were added

  16. Development of a methodology for the separation of europium and samarium from a mixture of rare earth oxides by electroreduction/ precipitation; Desenvolvimento de uma metodologia para a separacao de samario e europio a partir de mistura de oxidos de terras raras por reducao eletroquimica/precipitacao

    Energy Technology Data Exchange (ETDEWEB)

    Chepcanoff, Vera

    2006-07-01

    The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer industries, nuclear medicine, lasers, pigments, etc., moving, in the last decade , a market of US$ 2 billions per year. Due to their similar properties, the RE elements are very difficult to separate, requiring complex processes, what make the products very expensive. Elements like Eu and Sm, which contents in the minerals are low (0.05% and 2.0%, respectively, in monazite) are extremely expensive, but their field of application justifies the research for looking for other processes, more simple and/or more effective. Trivalent state is a characteristic of all RE, but some of them presents oxidation state +2, like Ce, Eu, Sm and Yb. In the case of Eu and Sm, the focus of the present work, the divalent state is achieved by electro-reduction in the potentials -0.65 and -1.55 (SCE), respectively. This makes possible the separation of these elements from the other rare earths and from each other. Thus, making use of this characteristic, a process for the individual separation of Eu and Sm in (NH{sub 4}){sub 2}SO{sub 4} solution by electro-reduction/precipitation is proposed, where Sm is first separated from the solution as sulfate, and Eu, that remains in the solution, is precipitated after the decrease of temperature and potential applied. The process developed from a synthetic Eu and Sm solution was applied to a mixture of semi-heavy RE oxide, produced at IPEN-CNEN/SP, obtaining the separation of Sm. This product was analyzed by spectrophotometry, showing high purity. (author)

  17. Tetrakis[μ-2-(3,4-dimethoxyphenylacetato]-κ4O:O′;κ3O,O′:O;κ3O:O,O′-bis{[2-(3,4-dimethoxyphenylacetato-κ2O,O′](1,10-phenanthroline-κ2N,N′samarium(III}

    Directory of Open Access Journals (Sweden)

    Jia-Lu Liu

    2010-11-01

    Full Text Available In the centrosymmetric dinuclear title complex, [Sm2(C10H11O46(C12H8N22], the SmIII ion is nine-coordinated by seven O atoms of five 2-(3,4-dimethoxyphenylacetate (DMPA ligands and two N atoms of one bis-chelating 1,10-phenanthroline (phen ligand, forming a distorted tricapped trigonal-prismatic environment. The DMPA ligands coordinate in bis-chelate, bridging and bridging tridentate modes. An intramolecular C—H...O hydrogen bond occurs. Intermolecular C—H...O interactions are also present in the crystal.

  18. Process Parameters Optimization of 14nm MOSFET Using 2-D Analytical Modelling

    National Research Council Canada - National Science Library

    Noor Faizah, Z.A; Ahmad, Ibrahim; Ker, P.J; Siti Munirah, Y; Mohd Firdaus, R; Md. Fazle, E; Menon, P. S

    2016-01-01

    ... (WSi2) and Titanium Silicide (TiSi2) as a metal gate for NMOS and PMOS respectively. The devices are fabricated virtually using ATHENA module and characterized its performance evaluation via ATLAS module...

  19. On the microstructure and interfacial properties of sputtered nickel ...

    Indian Academy of Sciences (India)

    SEM) and atomic force microscope (AFM) revealed columnar morphology with voided boundaries for films deposited at room temperature and was retained after post-deposition annealing at higher temperatures. Nickel silicide formation with ...

  20. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  1. EVALUATION OF THERMAL PROTECTIVE SYSTEMS FOR ADVANCED AEROSPACE VEHICLES. VOLUME II: APPENDICES.

    Science.gov (United States)

    AEROSPACE CRAFT, TABLES(DATA), GRAPHICS, OXIDES, BERYLLIUM, HAFNIUM COMPOUNDS, SPINEL, ZIRCONIUM COMPOUNDS, NITRIDES, CARBIDES, BORIDES , SILICIDES...GRAPHITE, NIOBIUM, MOLYBDENUM , TANTALUM, TUNGSTEN, THERMAL PROPERTIES, THERMAL PROPERTIES, SPECIFIC HEAT.

  2. Lightweight Ultrahigh Temperature CMC-Lined C/C Combustion Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA and DoD are seeking economical and high-performance bipropellant thrusters for various applications. These goals cannot be achieved using the silicided C103...

  3. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers, Phase II Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  4. Electronic and chemical structure of metal-silicon interfaces

    Science.gov (United States)

    Grunthaner, P. J.; Grunthaner, F. J.

    1984-01-01

    This paper reviews our current understanding of the near-noble metal silicides and the interfaces formed with Si(100). Using X-ray photoemission spectroscopy, we compare the chemical composition and electronic structure of the room temperature metal-silicon and reacted silicide-silicon interfaces. The relationship between the interfacial chemistry and the Schottky barrier heights for this class of metals on silicon is explored.

  5. Metallization of Large Silicon Wafers

    Science.gov (United States)

    Pryor, R. A.

    1978-01-01

    A metallization scheme was developed which allows selective plating of silicon solar cell surfaces. The system is comprised of three layers. Palladium, through the formation of palladium silicide at 300 C in nitrogen, makes ohmic contact to the silicon surface. Nickel, plated on top of the palladium silicide layer, forms a solderable interface. Lead-tin solder on the nickel provides conductivity and allows a convenient means for interconnection of cells. To apply this metallization, three chemical plating baths are employed.

  6. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    Science.gov (United States)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  7. Preparation, and Luminescence Properties of SiO2@Sm(MABA-Siphen Core-Shell Structure Nanometer Composite

    Directory of Open Access Journals (Sweden)

    Feng Li-Na

    2018-01-01

    Full Text Available A novel ternary samarium complex was prepared using HOOCC6H4N(CONH(CH23Si- (OCH2CH332 (MABA-Si as first ligand, and phen as second ligand. The corresponding SiO2@Sm(MABA-Siphen core-shell structure nanometer composite was synthesized as well, and the silica spheres was the core, and the ternary samarium complex was the shell layer. The ternary samarium complex has been characterized by element analysis, molar conductivity and IR spectra. The results show that the chemical formula of the complex is Sm(MABA-Si(phen2(ClO43·2H2O. The fluorescent spectra illustrat that the luminescence properties of the samarium complex are superior. The core-shell structure of SiO2@Sm(MABA-Siphen nanometer composite is characterized by SEM, TEM and IR spectra. The SiO2@Sm(MABA-Siphen core-shell structure composites exhibit stronger emission intensity than the ternary samarium complex. The fluorescence lifetime of the complex and core-shell structure composite is measured as well.

  8. Udvikling af materialer til brintpermeable membraner

    DEFF Research Database (Denmark)

    Bentzer, Henrik Karnøe

    Due to global warming as well as other factors, it is necessary to find alternatives to the current consumption of fossil fuels. Oxide materials with high protonic conductivity can potentially find application within many different technological fields in a society that is based on renewable energy...... doped samarium titanate, lanthanum magnesium titanate and strontium cerate doped with yttrium and nickel. Concentration cell measurements were used to estimate transport numbers for protons and oxide ions in yttrium doped strontium cerate and calcium doped samarium titanate. Furthermore, the voltage...

  9. {6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(ethanol-1κO-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-samarium(IIIzinc(II

    Directory of Open Access Journals (Sweden)

    Qiang Huang

    2009-10-01

    Full Text Available In the title heteronuclear ZnII–SmIII complex, [SmZn(C18H18N2O4(NO33(CH3CH2OH], with the hexadentate Schiff base compartmental ligand N,N′-bis(3-methoxysalicylideneethylenediamine (H2L, the SmIII and ZnII ions are triply bridged by two phenolate O atoms from the Schiff base ligand and one nitrate anion. The five-coordinate ZnII ion is in a square-pyramidal geometry formed by the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The SmIII center is in a ten-fold coordination of O atoms, involving the phenolate O atoms, two methoxy O atoms, one ethanol O atom, and two O atoms from two nitrate anions and one from the bridging nitrate anion. In the crystal, intermolecular O—H...O and C—H...O interactions generate a layer structure extending parallel to (101.

  10. Organometallic Routes into the Nanorealms of Binary Fe-Si Phases

    Science.gov (United States)

    Kolel-Veetil, Manoj K.; Keller, Teddy M.

    2010-01-01

    The Fe-Si binary system provides several iron silicides that have varied and exceptional material properties with applications in the electronic industry. The well known Fe-Si binary silicides are Fe3Si, Fe5Si3, FeSi, α-FeSi2 and β-FeSi2. While the iron-rich silicides Fe3Si and Fe5Si3 are known to be room temperature ferromagnets, the stoichiometric FeSi is the only known transition metal Kondo insulator. Furthermore, Fe5Si3 has also been demonstrated to exhibit giant magnetoresistance (GMR). The silicon-rich β-FeSi2 is a direct band gap material usable in light emitting diode (LED) applications. Typically, these silicides are synthesized by traditional solid-state reactions or by ion beam-induced mixing (IBM) of alternating metal and silicon layers. Alternatively, the utilization of organometallic compounds with reactive transition metal (Fe)-carbon bonds has opened various routes for the preparation of these silicides and the silicon-stabilized bcc- and fcc-Fe phases contained in the Fe-Si binary phase diagram. The unique interfacial interactions of carbon with the Fe and Si components have resulted in the preferential formation of nanoscale versions of these materials. This review will discuss such reactions.

  11. Organometallic Routes into the Nanorealms of Binary Fe-Si Phases

    Directory of Open Access Journals (Sweden)

    Teddy M. Keller

    2010-02-01

    Full Text Available The Fe-Si binary system provides several iron silicides that have varied and exceptional material properties with applications in the electronic industry. The well known Fe-Si binary silicides are Fe3Si, Fe5Si3, FeSi, a-FeSi2 and b-FeSi2. While the iron-rich silicides Fe3Si and Fe5Si3 are known to be room temperature ferromagnets, the stoichiometric FeSi is the only known transition metal Kondo insulator. Furthermore, Fe5Si3 has also been demonstrated to exhibit giant magnetoresistance (GMR. The silicon-rich b-FeSi2 is a direct band gap material usable in light emitting diode (LED applications. Typically, these silicides are synthesized by traditional solid-state reactions or by ion beam-induced mixing (IBM of alternating metal and silicon layers. Alternatively, the utilization of organometallic compounds with reactive transition metal (Fe-carbon bonds has opened various routes for the preparation of these silicides and the silicon-stabilized bcc- and fcc-Fe phases contained in the Fe-Si binary phase diagram. The unique interfacial interactions of carbon with the Fe and Si components have resulted in the preferential formation of nanoscale versions of these materials. This review will discuss such reactions.

  12. Performance Characterization of a Novel Plasma Thruster to Provide a Revolutionary Operationally Responsive Space Capability with Micro- and Nano-Satellites

    Science.gov (United States)

    2011-03-24

    Einstein Spontaneous Emission Rate Coefficient Electrical Utilization Efficiency Electron Electron Density...0.135 Tesla samarium cobalt (SmCo) permanent magnet from Electron Energy Corp. in Landisville, PA. Encapsulating the assembly is a simple aluminum...unlike some well-developed technologies, such as solid fueled rocket motors , an electric propulsion system could simultaneously contribute to all three

  13. Xe-135 and Sm-149 Isotopic Evolution Analysis Xesamo code; Analisis de la Evolucion Isotopica del Xe-135 y Sm-149. Programa Xesamo

    Energy Technology Data Exchange (ETDEWEB)

    Caro, R.; Gallego, J.; Martinez Fanegas, R.

    1977-07-01

    In this report the time evolution analysis of the nuclides concentration Xe-135 and Sm-149 as a function of the neutron flux is carried out. The neutron flux may be any function of time. It is analyzed as well the reactivity changes associated with the xenon and samarium concentration variations. (Author) 5 refs.

  14. Thermoluminescence characteristics of Sm doped NaYF4 crystals

    Indian Academy of Sciences (India)

    2006-06-28

    Jun 28, 2006 ... temperature peaks also vary in relation to the Sm3+ con- centration in NaYF4. This indicates a probable change in the trap structure of NaYF4 with the doping concentration of samarium impurity. This observation is in conformity with the earlier studies (Narasimha Reddy et al 1987;. Gopal Reddy et al 1988; ...

  15. Multiplet effects in the electronic structure of light rare-earth metals

    NARCIS (Netherlands)

    Lebegue, S.; Svane, A.; Katsnelson, M.I.; Lichtenstein, A.I.; Eriksson, O.

    2006-01-01

    The excited-state properties of the light rare-earth elemental metals praseodymium, neodymium, and samarium are studied within the Hubbard-I formalism. This method describes the multiplets of the rare-earth f shell by an exact diagonalization of the two-body part of the Hamiltonian. Subsequently,

  16. Structural, dielectric and electrical properties of Sm-modified Pb ...

    Indian Academy of Sciences (India)

    It is observed that. the dielectric permittivity () and loss tangent (tan ) are dependent on frequency,; the temperature of dielectric permittivity maximum shifts toward lower temperature side with the increase of samarium ion (Sm+3) concentration at the Pb sites, and; observed and calculated -values of XRD patterns show ...

  17. Ironless-armature brushless motor

    Science.gov (United States)

    Fisher, R. L.

    1977-01-01

    Device uses 12-pole samarium cobalt permanent-magnet rotor and three Hall-effect sensors for commutation. In prototype motor, torque constant (3-phase delta) is 65 oz-in/amp; electrical time constant (L/R) is 0.2 x 0.001 sec, and armature resistance is 20 ohms.

  18. Measurement of total angular momentum values of high-lying even ...

    Indian Academy of Sciences (India)

    Measurement of total angular momentum values of high-lying even-parity atomic states of samarium by spectrally resolved laser-induced fluorescence technique. A K PULHANI∗, M L SHAH, G P GUPTA and B M SURI. Laser and Plasma Technology Division, Bhabha Atomic Research Centre,. Mumbai 400 085, India.

  19. Measurement of total angular momentum values of high-lying even ...

    Indian Academy of Sciences (India)

    Spectrally resolved laser-induced fluorescence technique was used to uniquely assign total angular momentum () values to high-lying even-parity energy levels of atomic samarium. Unique value assignment was done for seven energy levels in the energy region 34,800–36,200 cm-1 , recently observed and reported in ...

  20. X-Ray studies reveal lanthanide binding sites at the A/B5 interface of E. coli heat labile enterotoxin

    NARCIS (Netherlands)

    Sixma, Titia K.; Terwisscha van Scheltinga, Anke C.; Kalk, Kor H.; Zhou, Kangjing; Wartna, Ellen S.; Hol, Wim G.J.

    1992-01-01

    The crystal structure determination of heat labile enterotoxin (LT) bound to two different lanthanide ions, erbium and samarium, revealed two distinct ion binding sites in the interface of the A subunit and the B pentamer of the toxin. One of the interface sites is conserved in the very similar

  1. X-RAY STUDIES REVEAL LANTHANIDE BINDING-SITES AT THE A/B5 INTERFACE OF ESCHERICHIA-COLI HEAT LABILE ENTEROTOXIN

    NARCIS (Netherlands)

    SIXMA, TK; VANSCHELTINGA, ACT; KALK, KH; WARTNA, ES; HOL, WGJ

    1992-01-01

    The crystal structure determination of heat labile enterotoxin (LT) bound to two different lanthanide ions, erbium and samarium, revealed two distinct ion binding sites in the interface of the A subunit and the B pentamer of the toxin. One of the interface sites is conserved in the very similar

  2. Author Details

    African Journals Online (AJOL)

    Prasad, T.N.V.K.. Vol 12, No 2 (2003) - Articles Pyroelectric Ferroelectric and Resistivity Studies on Samarium Modified Barium Strontium Sodium Niobate Ceramics Abstract. ISSN: 1019-1593. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  3. Thermoluminescent coactivated rare earth oxyhalide phosphors and X-ray image converters utilizing said phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Rabatin, J.G.

    1984-11-06

    Oxyhalides of lanthanum, gadolinium and lutetium coactivated with a first activator selected from bismuth and samarium to provide the color of light emission and a second coactivator which increases the amount of stored energy in a stored radiographic latent image are found to be superior in their conversion efficiency of x-rays to visible light.

  4. Interactions between exogenous rare earth elements and phosphorus leaching in packed soil columns

    Science.gov (United States)

    Rare earth elements (REEs) increasingly used in agriculture as an amendment for crop growth may help to lessen environmental losses of phosphorus (P) from heavily fertilized soils. The vertical transport characteristics of P and REEs, lanthanum (La), neodymium (Nd), samarium (Sm), and cerium (Ce), w...

  5. Simplified syntheses of the water-soluble chiral shift reagents Sm-(R)-pdta and Sm-(S)-pdta

    Czech Academy of Sciences Publication Activity Database

    Hrubá, L.; Buděšínský, Miloš; Pícha, Jan; Jiráček, Jiří; Vaněk, Václav

    2013-01-01

    Roč. 54, č. 47 (2013), s. 6296-6297 ISSN 0040-4039 Institutional support: RVO:61388963 Keywords : NMR * chiral shift reagents * Sm-pdta * PDTA * samarium * 1,2-diaminopropane Subject RIV: CC - Organic Chemistry Impact factor: 2.391, year: 2013

  6. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  7. Lanthanide(III) complexes with tridentate Schiff base ligand ...

    African Journals Online (AJOL)

    The tridentate N4-type Schiff base was synthesized from the condensation reaction of 2-hydrazinopyridine and pyridine-2-carbaldehyde. Neodymium and Samarium complexes were isolated when the corresponding nitrate salt was added to the solution of the ligand. The isolated compounds were characterized by ...

  8. Author Details

    African Journals Online (AJOL)

    T. Chen, W. Vol 31, No 3 (2017) - Articles A novel samarium complex with interesting photoluminescence and semiconductive properties. Abstract PDF. ISSN: 1726-801X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms ...

  9. Process Parameters Optimization of 14nm MOSFET Using 2-D Analytical Modelling

    OpenAIRE

    Noor Faizah Z.A.; Ahmad Ibrahim; Ker P.J.; Siti Munirah Y.; Mohd Firdaus R.; Md. Fazle E.; Menon P. S.

    2016-01-01

    This paper presents the modeling and optimization of 14nm gate length CMOS transistor which is down-scaled from previous 32nm gate length. High-k metal gate material was used in this research utilizing Hafnium Dioxide (HfO2) as dielectric and Tungsten Silicide (WSi2) and Titanium Silicide (TiSi2) as a metal gate for NMOS and PMOS respectively. The devices are fabricated virtually using ATHENA module and characterized its performance evaluation via ATLAS module; both in Virtual Wafer Fabricati...

  10. Electronic structure of erbium suicide ultra-thin films

    Science.gov (United States)

    Veuillen, J.-Y.; Tan, T. A. Nguyen; Lollman, D. B. B.

    1993-08-01

    The electronic structure of erbium silicide ultra-thin films epitaxially grown on Si(111) has been studied by means of angle-resolved ultra-violet photoemission spectroscopy (ARUPS) in the coverage range 0.2-4 monolayers (ML). Some peaks probably related to the silicide surface atomic structure are observed at any coverage. Features that appear at normal emission in connection with an R3 superstructure are ascribed to vacancy-induced states in the silicon surface plane. No true interface states could be identified in this study.

  11. Chemical bonding and charge redistribution - Valence band and core level correlations for the Ni/Si, Pd/Si, and Pt/Si systems

    Science.gov (United States)

    Grunthaner, P. J.; Grunthaner, F. J.; Madhukar, A.

    1982-01-01

    Via a systematic study of the correlation between the core and valence level X-ray photoemission spectra, the nature of the chemical bonding and charge redistribution for bulk transition metal silicides has been examined. Particular emphasis is placed on Pt2Si and PtSi. It is observed that the strength of the metal (d)-silicon (p) interaction increases in the order Ni2Si, Pd2Si, Pt2Si. It is also observed that both the metal and silicon core lines shift to higher binding energy as the silicides are formed. The notion of charge redistribution for metallic bonds is invoked to explain these data.

  12. The effect of rare-earth filtration on organ doses in intraoral radiography

    Energy Technology Data Exchange (ETDEWEB)

    Asako, Satoshi; Satoh, Kenji; Furumoto, Keiichi (Nippon Dental Univ., Tokyo (Japan))

    1994-08-01

    Filters of rare-earth elements such as lanthanum (La, Z=57), samarium (Sm, Z=62), gadolinium (Gd, Z=64) and erbium (Er, Z=68) are frequently used in radiography for the purpose of reducing the patient dose by eliminating low-energy and high-energy X-rays which are not involved in imaging. It is useful to evaluate the dose reduction achieved by these rare-earth filters in terms of organ dose, and the effective dose equivalent, which is used for evaluating carcinogenic risks and hereditary effects of X-ray irradiation, for the purpose of optimizing the radiographic technique and radiation protection. Therefore, we calculated the organ dose and effective dose equivalent during intraoral radiography of the maxillary incisor region by simulation using samarium or erbium, typical rare-earth elements, in filtration. We evaluated the effects of these metals in dose reduction. When samarium or erbium, 0.1 mm thick, was used in added filtration at tube voltage of 60, 70, 80 and 90 kV, the time required for radiography almost doubled, respectively. The organ dose at each tube voltage was the largest in the parathyroid and thyroid glands, followed by bone surfaces and the optic lenses, skin, red bone marrow and salivary glands, larynx, and brain, in that order. The organ dose at sites other than the larynx and brain decreased as the quality of the incident X-ray beam was hardened. When samarium or erbium was added at each voltage, the effective dose equivalent was reduced by about 20% to 45%. Erbium was more effective than samarium in reducing the effective dose equivalent, and either of the two elements decreased its effectiveness with an increase in tube voltage. (author) 43 refs.

  13. Page 1 Bull. Mater. Sci., Vol. 18, No. 5, September 1995, pp. 531 ...

    Indian Academy of Sciences (India)

    Both decrease in device dimensions and a drive for very high speed have increased the demand for improved interconnects with low resistanceſcapacitance (RC) coupling. Thin films of refractory metal silicides have been the subject of much interest in recent years owing to their widespread use as contact materials in VLSI.

  14. Quantitative strain analysis for advanced CMOS technology by Nano Beam Diffraction

    KAUST Repository

    Wang, Qingxiao

    2010-07-01

    Nano Beam Diffraction has been used to analyze the local strain distribution in MOS transistors. The influence of wafer process on the channel strain has been systematically analyzed in this paper. The source/drain implantation can cause a little strain loss but the silicidation step is the key process in which dramatic strain loss has been found. © 2010 IEEE.

  15. Atomic Structure Studies of Semiconductor-Electrolyte, Metal and Vacuum Interfaces.

    Science.gov (United States)

    1982-01-12

    Channeling Studies of Metal Interaction with Silicon R. Haight, T. Itoh, T. Narusawa, W.M. Gibson and A. Hiraki Epitaxial Growth of Germanium on Si(lll...Stages of Metal-Silicide Formation (Invited Paper) A. Hiraki , T. Narusawa and W.M. Gibson 44 American Physical Society, Dallas, TX, March 1982 Structure

  16. Fabrication and microstructural analysis of UN-U{sub 3}Si{sub 2} composites for accident tolerant fuel applications

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Kyle D., E-mail: kylej@kth.se; Raftery, Alicia M.; Lopes, Denise Adorno; Wallenius, Janne

    2016-08-15

    In this study, U{sub 3}Si{sub 2} was synthesized via the use of arc-melting and mixed with UN powders, which together were sintered using the SPS method. The study revealed a number of interesting conclusions regarding the stability of the system – namely the formation of a probable but as yet unidentified ternary phase coupled with the reduction of the stoichiometry in the nitride phase – as well as some insights into the mechanics of the sintering process itself. By milling the silicide powders and reducing its particle size ratio compared to UN, it was possible to form a high density UN-U{sub 3}Si{sub 2} composite, with desirable microstructural characteristics for accident tolerant fuel applications. - Highlights: • U{sub 3}Si{sub 2} fabricated from elemental uranium and silicon through arc melting. • Homogeneity of the silicides assessed through densitometry, XRD, SEM and EDS, chemical etching and optical microscopy. • UN powder fabricated using hydriding-nitriding method. • No phase transformations detected when sintering using silicide particle sizes less than UN particle size. • High density composite (98%TD) fabricated with silicide grain coating using spark plasma sintering at 1450 °C.

  17. Charge plasma diode - a novel device concept

    NARCIS (Netherlands)

    Rajasekharan, B.; Hueting, Raymond Josephus Engelbart; Salm, Cora; Hoang, T.; Schmitz, Jurriaan

    2008-01-01

    We propose a new device concept called charge plasma (CP) diode [1]. The diodes are with metal/silicided contacts of different workfunctions and thin intrinsic region in between. The workfunctions and layer thicknesses are chosen such that an electron plasma is formed on one side of the silicon body

  18. Contact and Alignment Marker Technology for Atomic Scale Device Fabrication

    NARCIS (Netherlands)

    Zuiddam, M.R.; Rogge, S.; Drift, E. van der; Ilge, B.; Palasantzas, G.

    1998-01-01

    This article reports on the technology to link atomic scale structures to macroscopic contact pads. Dedicated processes for electrode pattern formation in several materials have been developed and characterised. For pattern formation in CoSi2 a thermal compromise between proper silicide formation

  19. Microwave synthesis of electrode materials for lithium batteries

    Indian Academy of Sciences (India)

    Unknown

    Bi4B2O9 have been used as cathodes (Jones and Akridge. 1995). ... reactive, is a superb secondary heater (Vaidhyanathan et al 1997). Researches at our laboratory and elsewhere have demonstrated the use of microwaves in the synthesis of a wide ... 1997a), silicides (Vaidhyanathan and Rao 1997b), borides. (Mingos ...

  20. High-temperature stability of yttria-stabilized zirconia thermal barrier ...

    Indian Academy of Sciences (India)

    bustor and vehicle acreage applications [19–21]. However, silicide coatings are generally used for oxidation ... Since, Nb alloys are being used for these applications, TBC with a prior bond coat is essential for better ..... ing; notwithstanding the bond coat mitigates the thermal mis- match between the metal substrate and YSZ ...

  1. DEVELOPMENT OF A HIGH TEMPERATURE LIQUID METAL SOLUTION CALORIMETER.

    Science.gov (United States)

    alloys and many inorganic compounds, including such materials as steels, refractory metal alloys, carbides, borides , and silicides. Because of the high...alumina is used for other parts. Heat is supplied through molybdenum wire resistance windings and controlled by a proportioning controller. Temperatures

  2. 78 FR 40131 - Proposed Subsequent Arrangement

    Science.gov (United States)

    2013-07-03

    ... concerns the retransfer of 86 kg of U.S.-origin uranium, 17 kg of which is in the isotope of U-235 (19.74 percent enrichment), in the form of low enriched uranium-silicide Open Pool ] Australian Lightwater (OPAL...

  3. Page 1 602 Material synthesis A simple hydrothermal cell for ...

    Indian Academy of Sciences (India)

    graphy 231. Metal-oxide semiconductor. Growth of polysilicon and silicide films for. MOS-VLSI application 297. Microcrystalline. Electron microscopy study of chemically depo- sited Ni-P films . 433. Microstrip. Microstrip losses with Al2O overlay 535. Microstrip rejection filter. Effect of bulk and thin film dielectric overlay on.

  4. Amorphous Ni–Zr layer applied for microstructure improvement of Ni-based ohmic contacts to SiC

    Energy Technology Data Exchange (ETDEWEB)

    Wzorek, M., E-mail: mwzorek@ite.waw.pl; Czerwinski, A.; Borysiewicz, M.A.; Gołaszewska, K.; Myśliwiec, M.; Ratajczak, J.; Piotrowska, A.; Kątcki, J.

    2015-09-15

    Highlights: • Thin Ni–Si layers on SiC were studied after annealing. • Different types of microstructural defects occur depending on Ni:Si ratio. • Mechanisms leading to morphology degradation are discussed. • Presented method improves the microstructure of ohmic contacts to SiC. - Abstract: The new approach to fabrication process of nickel-based ohmic contacts to silicon carbide (SiC) is presented. During the first annealing step (300 °C), the amorphous Ni–Zr layer retards diffusion between two nickel silicide layers, thus handling the contradictory requirements for optimal Ni:Si ratio. Different stoichiometry obtained in each silicide layer allows to preserve smooth interface with SiC and simultaneously to avoid relatively easily meltable Si-rich Ni–Si phases during high temperature annealing (1000 °C) and therefore prevents morphology degradation. After annealing at 1000 °C only one final nickel silicide layer is present and Zr atoms are agglomerated at its surface. Morphology of the final silicide layer is substantially improved when compared to typical Ni-based contacts obtained by similar high-temperature annealings. The improved microstructure of the ohmic contact is a promising advantage in terms of SiC devices reliability.

  5. An Incommensurately Modulated Structure of eta '-Phase of Cu3+xSi Determined by Quantitative Electron Diffraction Tomography

    Czech Academy of Sciences Publication Activity Database

    Palatinus, L.; Klementová, Mariana; Dřínek, V.; Jarošová, M.; Petříček, V.

    2011-01-01

    Roč. 50, č. 8 (2011), s. 3743-3751 ISSN 0020-1669 R&D Projects: GA ČR GA203/09/1088 Institutional research plan: CEZ:AV0Z40320502 Keywords : copper silicide * incommensurate structure * electron diffraction tomography * ab inition structure solution * superspace Subject RIV: CA - Inorganic Chemistry Impact factor: 4.601, year: 2011

  6. Gap-closing test structures for temperature budget determination

    NARCIS (Netherlands)

    Faber, Erik Jouwert; Wolters, Robertus A.M.; Schmitz, Jurriaan

    2011-01-01

    We present the extension of a method for determining the temperature budget of the process side of silicon substrates and chips, employing silicide formation reactions. In this work, silicon-on-insulator type substrates are used instead of bulk silicon wafers. By an appropriate choice of the layer

  7. Characterization of electroless nickel as a seed layer for silicon solar ...

    Indian Academy of Sciences (India)

    based solar cell metallization. Nickel silicide formation and hence contact resistivity of the interface is largely influenced by the plating process and annealing conditions. In the present work, a thin seed layer is deposited from neutral pH and ...

  8. Structural and electrical properties of swift heavy ion beam irradiated ...

    Indian Academy of Sciences (India)

    Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. We have investigated the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations were undertaken at room temperature using 120 MeV Au ions at the ...

  9. Substrate bias voltage and deposition temperature dependence on ...

    Indian Academy of Sciences (India)

    ... on Si (100) substrate. Deposition at higher substrate temperature causes the film to react with Si forming silicides at the film/Si substrate interface. Ti film undergoes a microstructural transition from hexagonal plate-like to round-shaped grains as the substrate temperature was raised from 300 to 50 °C during film deposition ...

  10. Toward a better understanding of the magnetocaloric effect: An experimental and theoretical study of MnFe.sub.4./sub.Si.sub.3./sub..

    Czech Academy of Sciences Publication Activity Database

    Gourdon, O.; Gottschlich, G.; Persson, J.; de la Cruz, C.; Petříček, Václav; McGuire, M.A.; Bruckel, T.

    2014-01-01

    Roč. 216, AUG (2014), s. 56-64 ISSN 0022-4596 Grant - others:AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : magneto caloric effect materials * intermetallic * silicide * magnetism * neutron diffraction * density functional theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.133, year: 2014

  11. Phase equilibria in a ternary fullerenol-d(C60(OH)22-24)-SmCl3-H2O system at 25°C

    Science.gov (United States)

    Yur'ev, G. O.; Keskinov, V. A.; Semenov, K. N.; Charykov, N. A.

    2017-05-01

    The solubility in a ternary fullerenol-d (C60(OH)22-24)-SmCl3-H2O system at 25°C is studied via isothermal saturation in ampules. The solubility diagram is shown to be a simple eutonic one that consists of two branches corresponding to the crystallization of fullerenol-d (C60(OH)22-24 · 30H2O) and samarium(III) chloride SmCl3 · 6H2O crystallohydrates and contains one nonvariant eutonic point corresponding to saturation with both crystallohydrates. The long branch of C60(OH)22-24 · 30H2O crystallization shows the effect of fullerenol-d salting out of saturated solutions; in contrast, the short branch of SmCl3 · 6H2O crystallization shows the pronounced salting-in effect of samarium(III) chloride.

  12. Alkaline and alkaline earth metal phosphate halides and phosphors

    Science.gov (United States)

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  13. Reductive trapping of [(OC){sub 5}W-W(CO){sub 5}]{sup 2-} in a mixed-valent Sm{sup II/III} calix[4]pyrrolide sandwich

    Energy Technology Data Exchange (ETDEWEB)

    Deacon, Glen B.; Guo, Zhifang [School of Chemistry, Monash University, VIC (Australia); Junk, Peter C.; Wang, Jun [College of Science and Engineering, James Cook University, Townsville, QLD (Australia)

    2017-07-10

    Reduction of tungsten hexacarbonyl by the divalent samarium(II) complex [Sm{sub 2}(N{sub 4}Et{sub 8})(thf){sub 4}] ((N{sub 4}Et{sub 8}){sup 4-}=meso-octaethylcalix[4]pyrrolide) in toluene at ambient temperature gave the remarkable heteronuclear mixed-valent samarium(II/III)/tungsten complex [{(thf)_2Sm"I"I(N_4Et_8)Sm"I"I"I(thf)}{sub 2}{(μ-OC)_2W_2(CO)_8}], which features the trapping of a rare [W{sub 2}(CO){sub 10}]{sup 2-} anion with an unsupported W-W bond. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Preparation and dosimetry of radiotherapeutic particles for arthropaties; Preparacion y dosimetria de particulas radioterapeuticas para artropatias

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Z, M.A. [Departamento de Medicina Nuclear, Instituto Nacional de Pediatria (Mexico); Ferro F, G. [Departamento de Materiales Radiactivos, Instituto nacional de Investigaciones Nucleares, Salazar, Estado de Mexico C.P. 52045 (Mexico); Rivera M, T.; Azorin N, J. [Departamento de Fisica, UAM Iztapalapa, Mexico D.F. (Mexico)

    1999-07-01

    It was developed a new formulation of macro aggregates of Samarium 153 ({sup 153} Sm-MH) for the arthropaties treatment. The radio pharmaceutic was prepared by reaction of Samarium 153 chloride (SmCl{sub 3}) in aqueous environment with sodium boron hydride in NaOH 0.5 N. The microscopic analysis shown that the particles have an average size of 4% m (range 1-14 {mu} m). The velocity of sedimentation was 0.008 cm/min with high stability in vitro in human serum. The biological studies in healthy rabbits, shown that the complex is retained inside the articulation still eight days after of the administration of the radiopharmaceutical. Likewise, it is presented the data of absorbed dose in the different target organs, which was determined by thermoluminescent dosimetry (TLD) through the use of a REMCAL phantom (radiation equivalent manikin calibration). (Author)

  15. Ion-exchange separation of the rare earth elements by means of solution of ammonium phthalate and chloride

    Energy Technology Data Exchange (ETDEWEB)

    Hubicki, W.; Ozga, W. (Uniwersytet Marii Curie-Sklodowskiej, Lublin (Poland))

    1976-01-01

    A new method of ion exchange separation of lanthanons by the use of equimolar solution of ammonium phthalate and ammonium chloride as an eluent was elaborated. This method allows to separate light lanthanons and to obtain concentrate of samarium and heavy lanthanons. 99.99% Y/sub 2/O/sub 3/ was obtained from non-neodymium concentration with 47.4% efficiency. The influence of change in concentration and pH of eluent on the effectiveness of separation was examined. It was found that an increase in concentration of eluent and pH leads to quick separation of yttrium from samarium and heavy lanthanons. However, the efficiency of pure Y/sub 2/O/sub 3/ decreases distinctly.

  16. Large directional optical anisotropy in multiferroic ferroborate

    Science.gov (United States)

    Kuzmenko, A. M.; Dziom, V.; Shuvaev, A.; Pimenov, Anna; Schiebl, M.; Mukhin, A. A.; Ivanov, V. Yu.; Gudim, I. A.; Bezmaternykh, L. N.; Pimenov, A.

    2015-11-01

    One of the most fascinating and counterintuitive recent effects in multiferroics is directional anisotropy, the asymmetry of light propagation with respect to the direction of propagation. In such case the absorption in a material can be different for opposite directions. Besides absorption, different velocities of light for different directions of propagation may be also expected, which is termed directional birefringence. In this work, we demonstrate large directional anisotropy in multiferroic samarium ferroborate. The effect is observed for linear polarization of light in the range of millimeter wavelengths, and it survives down to low frequencies. The dispersion and absorption close to the electromagnon resonance can be controlled by external magnetic field and are fully suppressed in one direction. By changing the geometry of the external field, samarium ferroborate shows giant optical activity, which makes this material a universal tool for optical control: with a magnetic field as an external parameter it allows switching between two functionalities: polarization rotation and directional anisotropy.

  17. Ionic liquid technology for recovery and separation of rare earths

    OpenAIRE

    Binnemans, Koen

    2015-01-01

    End-of-life neodymium-iron-boron and samarium-cobalt permanent magnets, fluorescent lamps and metal hydride batteries are valuable secondary resources of rare earths. These resources are characterised by relatively small volumes, but high concentrations of rare earths [1]. On the other hand, industrial process residues such as bauxite residue (red mud) and phosphogypsum contain low concentrations of rare earths, but are available in huge volumes [2]. Recovery of rare earths from end-of-life c...

  18. Ternary rare earth-lanthanide sulfides

    Science.gov (United States)

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.

    1987-01-06

    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to 1000.degree. C.

  19. Structural and physical properties of Sm doped magnesium zinc ...

    Indian Academy of Sciences (India)

    2017-09-22

    Sep 22, 2017 ... Abstract. Samarium (Sm3+) doped magnesium zinc sulfophosphate glass system of composition (60–x)P2O5–20MgO–. 20ZnSO4–xSm2O3 (x = 0.0, 0.5, 1.0, 1.5 and 2.0 mol%) were synthesized using melt-quenching technique. The structure and physical properties of prepared glass samples were ...

  20. Structural aspects of displacive transformations: what can optical microscopy contribute? Dehydration of Sm2(C2O4)3·10H2O as a case study.

    Science.gov (United States)

    Matvienko, Alexander A; Maslennikov, Daniel V; Zakharov, Boris A; Sidelnikov, Anatoly A; Chizhik, Stanislav A; Boldyreva, Elena V

    2017-09-01

    For martensitic transformations the macroscopic crystal strain is directly related to the corresponding structural rearrangement at the microscopic level. In situ optical microscopy observations of the interface migration and the change in crystal shape during a displacive single crystal to single crystal transformation can contribute significantly to understanding the mechanism of the process at the atomic scale. This is illustrated for the dehydration of samarium oxalate decahydrate in a study combining optical microscopy and single-crystal X-ray diffraction.

  1. Installation of electric generators on turbine engines

    Science.gov (United States)

    Demel, H. F.

    1983-01-01

    The installation of generators on turbine aircraft is discussed. Emphasis is placed on the use of the samarium cobalt generator. Potential advantages of an electric secondary power system at the engine level are listed. The integrated generator and the externally mounted generator are discussed. It is concluded that the integrated generator is best used in turbojet and low bypass ratio engines where there is no easy way of placing generators externally without influencing frontal areas.

  2. Fabrication of Material and Devices for Very High Density Information Storage.

    Science.gov (United States)

    1986-11-24

    crystal bismuth doped garnets , having properties equivalent to IPE grown materials,,’., onto gadolinium gallium garnet substrates. There was speculation... LPE onto0 (111)-.""’’ oriented calcium-, magnesium- or zirconium-substituted gadolinium, samarium or neodymium gallium /’’’ garnet substrates. Garnet ...properties of LPE garnetmusesit favor garnets a s a t arting poiut. ref og Vmagnetic and m g e-optical po et s o a- , pae d m u , alu inu-%, li

  3. Macrocyclic aminophosphonic acid complexes, their preparation, formulations and use; Fremgangsmaate for fremstilling av et makrocyklisk aminofosfonsyrekompleks eller et fysiologisk akseptabelt salt derav

    Energy Technology Data Exchange (ETDEWEB)

    Simon, J.; Wilson, D.A.; Garlich, J.R.; Troutner, D.E.

    1997-01-13

    Particle emitting radionuclides, e.g. Samarium-153, have been complexed with certain macrocyclic aminophosphonic acids wherein the nitrogen and phosphorus are interconnected by an alkylene group or substituted alkylene group. A composition is now disclosed which comprises a complex having a macrocyclic aminophosphonic acid, containing 1,4,7,10-tetraazycyclododecane as the macrocyclic moiety, or a physiologically, acceptable salt thereof, wherein the nitrogen and phosphorus are interconnected by an alkylene or substituted alkylene radical. 10 tabs.

  4. Effect of Flake Thickness on Coercivity of Nanocrystalline SmCo5 Bulk Prepared from Anisotropic Nanoflake Powder (Postprint)

    Science.gov (United States)

    2016-08-23

    flake thickness. 15. SUBJECT TERMS rare earth magnets , samarium cobalt magnets , permanent magnets 16. SECURITY CLASSIFICATION OF: 17...nanoflakes have attractive magnetic properties ; coercivity of up to 21 kOe and maximum energy product of up to 22 MGOe.9 Thus, the nanoflake powders...less reported on correlation between nanoflake morphology and final properties of the SmCo5 bulk magnets . In this study, we prepared SmCo5 nanoflakes

  5. Cross sections of deuteron induced reactions on $^{nat}$Sm for production of the therapeutic radionuclide $^{145}$Sm and $^{153}$Sm

    OpenAIRE

    Tárkányi, F.; Hermanne, A.; Takács, S.; Ditrói, F.; Csikai, J.; Ignatyuk, A. V.

    2014-01-01

    At present, targeted radiotherapy (TR) is acknowledged to have great potential in oncology. A large list of interesting radionuclides is identified, including several radioisotopes of lanthanides, amongst them $^{145}$Sm and $^{153}$Sm. In this work the possibility of their production at a cyclotron was investigated using a deuteron beam and a samarium target. The excitation functions of the $^{nat}$Sm(d,x)$^{145153}$Sm reactions were determined for deuteron energies up to 50 MeV using the st...

  6. The effect of alloying on the ordering processes in near-alpha titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Popov, Artemiy, E-mail: p.artemii@mail.ru [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Rossina, Natalya [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Popova, Maria, E-mail: pmaria777@mail.ru [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation)

    2013-03-01

    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon.

  7. All-Si photodetector for telecommunication wavelength based on subwavelength grating structure and critical coupling

    Science.gov (United States)

    Taghizadeh, Alireza; Zali, Aref Rasoulzadeh; Chung, Il-Sug; Moravvej-Farshi, Mohammad Kazem

    2017-09-01

    We propose an efficient planar all-Si internal photoemission photodetector operating at the telecommunication wavelength of 1550 nm and numerically investigate its optical and electrical properties. The proposed polarization-sensitive detector is composed of an appropriately engineered subwavelength grating structure topped with a silicide layer of nanometers thickness as an absorbing material. It is shown that a nearly-perfect light absorption is possible for the thin silicide layer by its integration to the grating resonator. The absorption is shown to be maximized when the critical coupling condition is satisfied. Simulations show that the external quantum efficiency of the proposed photodetector with a 2-nm-thick PtSi absorbing layer at the center wavelength of 1550 nm can reach up to ˜60%.

  8. Nanoamorphous carbon-based photonic crystal infrared emitters

    Science.gov (United States)

    Norwood, Robert A [Tucson, AZ; Skotheim, Terje [Tucson, AZ

    2011-12-13

    Provided is a tunable radiation emitting structure comprising: a nanoamorphous carbon structure having a plurality of relief features provided in a periodic spatial configuration, wherein the relief features are separated from each other by adjacent recessed features, and wherein the nanoamorphous carbon comprises a total of from 0 to 60 atomic percent of one or more dopants of the dopant group consisting of: transition metals, lanthanoids, electro-conductive carbides, silicides and nitrides. In one embodiment, a dopant is selected from the group consisting of: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, La and other lanthanides, Hf, Ta, W, Rh, Os, Ir, Pt, Au, and Hg. In one embodiment, a dopant is selected from the group consisting of: electro-conductive carbides (like Mo.sub.2C), silicides (like MoSi.sub.2) and nitrides (like TiN).

  9. Isothermal and cyclic oxidation resistance of pack siliconized Mo-Si-B alloy

    Science.gov (United States)

    Majumdar, Sanjib

    2017-08-01

    Oxidation behaviour of MoSi2 coated Mo-9Si-8B-0.75Y (at.%) alloy has been investigated at three critical temperatures including 750, 900 and 1400 °C in static air. Thermogravimetric analysis (TGA) data indicates a remarkable improvement in the oxidation resistance of the silicide coated alloy in both isothermal and cyclic oxidation tests. The cross-sectional scanning electron microscopy and energy dispersive spectroscopic analysis reveal the occurrence of internal oxidation particularly at the crack fronts formed in the outer MoSi2 layer during thermal cycling. The dominant oxidation mechanisms at 750-900 °C and 1400 °C are identified. Development of MoB inner layer further improves the oxidation resistance of the silicide coated alloy.

  10. Accident-tolerant oxide fuel and cladding

    Science.gov (United States)

    Mariani, Robert D.

    2017-05-30

    Systems and methods for accident tolerant oxide fuel. One or more disks can be placed between fuel pellets comprising UO.sub.2, wherein such disks possess a higher thermal conductivity material than that of the UO.sub.2 to provide enhanced heat rejection thereof. Additionally, a cladding coating comprising zircaloy coated with a material that provides stability and high melting capability can be provided. The pellets can be configured as annular pellets having an annulus filled with the higher thermal conductivity material. The material coating the zircaloy can be, for example, Zr.sub.5Si.sub.4 or another silicide such as, for example, a Zr-Silicide that limits corrosion. The aforementioned higher thermal conductivity material can be, for example, Si, Zr.sub.xSi.sub.y, Zr, or Al.sub.2O.sub.3.

  11. Process-oriented microstructure evolution of V{sub ss}-V{sub 3}Si-V{sub 5}SiB{sub 2}; Prozessabhaengige Mikrostrukturausbildung von V{sub ss}-V{sub 3}Si-V{sub 5}SiB{sub 2}-Werkstoffen

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Manja; Koeppe-Grabow, Birte [Magdeburg Univ. (Germany)

    2017-05-15

    Vanadium silicide alloys are potentially interesting high temperature materials, since they combine high mechanical strength at temperatures of up to 1 000 C with a low density. In this study, the microstructures of innovative V-Si-B high temperature materials are examined using different analytical methods. The selected V-9Si-13B model alloy was manufactured using a powder metallurgical process route as well as an ingot metallurgical process. The alloys show a vanadium solid solution phase as well as the high-strength silicide phases V{sub 3}Si and V{sub 5}SiB{sub 2}. Especially for the powder metallurgically fabricated alloy, showing finely dispersed phases, the quantification of microstructural constituents is difficult. The phases, however, can be separated from one another via computer tomography.

  12. Schottky barrier height tuning using P+ DSS for NMOS contact resistance reduction

    Science.gov (United States)

    Khaja, Fareen Adeni; Rao, K. V.; Ni, Chi-Nung; Muthukrishnan, Shankar; Lei, Jianxin; Darlark, Andrew; Peidous, Igor; Brand, Adam; Henry, Todd; Variam, Naushad

    2012-11-01

    Nickel silicide (NiSi) contacts are adopted in advanced CMOS technology nodes as they demonstrate several benefits such as low resistivity, low Si consumption and formation temperature. But a disadvantage of NiSi contacts is that they exhibit high electron Schottky barrier height (SBH), which results in high contact resistance (Rc) and reduces the NMOS drive current. To reduce SBH for NMOS, we used phosphorous (P) ion implantation into NiPt silicide with optimized anneal in order to form dopant segregated Schottky (DSS). Electrical characterization was performed using test structures such as Transmission Line Model, Cross-Bridge Kelvin Resistor, Van der Pauw and diodes to extract Rc and understand the effects of P+ DSS on ΦBn tuning. Material characterization was performed using SIMS, SEM and TEM analysis. We report ˜45% reduction in Rc over reference sample by optimizing ion implantation and anneal conditions (spike RTA, milli-second laser anneals (DSA)).

  13. The Application of Nuclear Techniques to Solid State Devices.

    Science.gov (United States)

    1980-12-15

    characterized phenomeno- logically . Our efforts therefore addressed themselves toward broaden- ing the basis of experimental facts and deepening the...Italy C. L. Ramiller Student Intel Magnetics, Santa Clara, California J. L. Regolini Collaborator Stanford University, Stanford, California P. Revesz...316 (1978). 20. "Radioactive Silicon as a Marker in Thin-Film Silicide Formation", R. Pretorius, C. L. Ramiller , S. S. Lau and M-A. Nicolet, Appl. Phys

  14. Technical Operations Support III (TOPS III). Task Order 0061: Fundamental Theory Based Assessment of Thermoelectric Merit Factor for Heusler Alloys

    Science.gov (United States)

    2010-10-01

    can yet be commercialized. Moreover, these materials are not very practical due to scarcity of the elements, toxicity and decomposition-evaporation...are not very practical due to scarcity of the elements, toxicity and decomposition-evaporation problems at elevated temperatures [1]. Today, there...Maximum zT: 0.8 at over 1000K Atoms: 12 Lanthanum Aluminium Silicide (LaAlSi) Experimental Structure: cubic [a b c]: 5.94 Bandgap: (-) DFT(GGA) Energy

  15. Surface morphology and the phase formation at Cr/Si system

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Shivani [Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur 302004 (India)]. E-mail: shivani95@sify.com; Jain, Ankur [Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur 302004 (India); Lal, Chhagan [Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur 302004 (India); Ganesan, V. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore (India); Jain, I.P. [Centre for Non-Conventional Energy Resources, University of Rajasthan, Jaipur 302004 (India)]. E-mail: ipjain46@sify.com

    2007-03-15

    Metal silicide technology has been attracting attention worldwide and it constitutes an active, frontier area of research. Research in this area has not only stimulated the exploration of new phenomena, but is also leading to a technological revolution. Electron beam evaporation in ultra high vacuum (UHV) environment is one of the best techniques to grow thin metal film on Si substrate. Metal silicide contact is an interesting and important part of integrated circuit. Due to selective growth and high thermal stability metal silicides are used in very large scale integrated (VLSI) and ultra large scale integrated (ULSI) applications. In this paper our interest is to show GIXRD, XRR and SPM measurement on C (2 nm)/Cr (25 nm)/Si (1 0 0) system in which thin films were deposited using electron beam evaporation technique at 2 x 10{sup -8} Torr vacuum. The capping layer of 2 nm carbon is deposited to stop contamination. The C (2 nm)/Cr (25 nm)/Si (1 0 0) system were annealed in 10{sup -5} Torr vacuum at temperatures 300-600 deg. C to study the formation of chromium silicide. Structural properties at the interface has been studied by grazing incidence X-ray diffraction (GIXRD), which shows formation of Cr{sub 3}Si and CrSi{sub 2} as a result of interface mixing due to annealing. The morphology of the system was investigated by AFM in tapping mode. It was found that nano-rod type structures were formed with annealing at 600 deg. C temperature.

  16. Page 1 478 S Bandopadhyay et al Binding energy (eV) 84 O 85 O ...

    Indian Academy of Sciences (India)

    Figure 6. Expanded runs of the strongest XPS core lines, a. Ni2p doublet and b. Si2P. Table 1. Composition of nickel silicide film. XPS Amplitude FWHM Intensity ASF Relative atomic line (A;KCPS) [T;eV] (I, Kcps-eV) (si) concentration (C). Ni2pala (Eso = 852-6 eV) 135-2 2-4 324.5. Main line 3.7 0.49. Satellite. Eso = 857.8 ...

  17. Platinum Group Coatings for Refractory Metals

    Science.gov (United States)

    1984-06-01

    molybdenum , tungsten, tantalum, niobium, rhenium or carbon/carbon must be used to fabricate the parts to withstand these temperatures. These materials and...layers (eg silicides, borides ) o Alloy coatings that form compact oxide layers (Ni and Co F based alloys) o Stable oxides that provide physical barriers...thermally etched) surface and seems to promote adhesion. Molybdenum rods 3mm in diameter were used as substrates during many of the runs where the

  18. Infrared technology and applications; Proceedings of the Meeting, Cannes, France, November 26-29, 1985

    Science.gov (United States)

    Baker, Lionel R. (Editor); Masson, Andre (Editor)

    1986-01-01

    The present conference on state-of-the-art IR systems and components technologies and their applications encompasses developments in IR systems design, production technologies, IR component testing, IR systems evaluations, laboratory and industrial applications, and aerospace ranging sensor and surveillance sensor applications. Attention is given to IR zoom lens telescopes, large zinc sulphide windows for airborne applications, thermal imaging system evaluation, minimum resolvable temperature difference measurement methods, industrial use of IR spectroscopy, platinum silicide sensor imagery, and recent developments in laser rangefinders.

  19. Cobalt alloy ion sources for focused ion beam implantation

    Energy Technology Data Exchange (ETDEWEB)

    Muehle, R.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zimmermann, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Cobalt alloy ion sources have been developed for silicide formation by focused ion beam implantation. Four eutectic alloys AuCo, CoGe, CoY and AuCoGe were produced by electron beam welding. The AuCo liquid alloy ion source was investigated in detail. We have measured the emission current stability, the current-voltage characteristics, and the mass spectrum as a function of the mission current. (author) 1 fig., 2 refs.

  20. Self-Propagating High-Temperature Synthesis of Titanium Carbosilicide and Electrically Conductive Composite Coatings on its Basis

    Science.gov (United States)

    Shulpekov, A. M.; Lepakova, O. K.; Golobokov, N. N.; Dyukarev, M. A.

    2017-09-01

    Titanium carbosilicide is obtained by the method of self-propagating high-temperature synthesis with titanium and ferrosilicon (with silicon content of 80 mass %) used as initial products. Addition of TiSi2 to the endproduct with the subsequent heat treatment allows the content of titanium silicide to be increased. The materials based on titanium carbosilicide provide electroconductivity of polymer composite coatings at temperatures exceeding 350°C.

  1. An incommensurately modulated structure of eta '-phase of Cu.sub.3+x./sub.Si determined by quantitative electron diffraction tomography

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; Klementová, Mariana; Dřínek, Vladislav; Jarošová, Markéta; Petříček, Václav

    2011-01-01

    Roč. 50, č. 8 (2011), s. 3743-3751 ISSN 0020-1669 R&D Projects: GA ČR GA203/09/1088 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40720504 Keywords : copper silicide * incommensurate structure * electron diffraction tomography * ab inition structure solution * superspace Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.601, year: 2011

  2. Alternative Plasmonic Materials: Beyond Gold and Silver

    DEFF Research Database (Denmark)

    Naik, Gururaj V.; Shalaev, Vladimir M.; Boltasseva, Alexandra

    2013-01-01

    such as gold and silver, that exhibit metallic properties and provide advantages in device performance, design flexibility, fabrication, integration, and tunability. This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent...... conducting oxides, perovskite oxides, metal nitrides, silicides, germanides, and 2D materials such as graphene. This review provides a summary of the recent developments in the search for better plasmonic materials and an outlook of further research directions....

  3. High Temperature Interactions of Metallic Matrices with Ceramic Reinforcements

    Science.gov (United States)

    1990-12-31

    temperatura range were extensive; various metal silicides, metalIcarbides, ternary metal-slilcon-carbides, and unreacted carbon were formed as layered...Couples 3.2.1 Preparation of SiC Ceramic: The polycrystalline SiC substrates, designated as Hexoloy, were obtained from the Carborundum Corporation ...and was received from Engelhard Corporation . The metal pieces were cut into a similar size to that of the SiC, mechanically ground with #600 SiC papers

  4. Transmission electron microscopy study on silicon nitride/stainless steel bonded interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Poza, P. [Departamento de Ciencia e Ingenieria de los Materiales, Universidad Rey Juan Carlos, 28933 Mostoles, Madrid (Spain); Miranzo, P. [Institute of Ceramics and Glass, CSIC, Campus de Cantoblanco, 28049 Madrid (Spain); Osendi, M.I. [Institute of Ceramics and Glass, CSIC, Campus de Cantoblanco, 28049 Madrid (Spain)], E-mail: miosendi@icv.csic.es

    2008-11-28

    The reaction zone of a diffusion bonded Si{sub 3}N{sub 4}/stainlees steel (ss) interface formed at 1100 deg. C was analyzed by transmission electron microscopy and X-ray diffraction (XRD). Besides the formation of various iron silicides, iron nitride and chromium nitride phases detected by XRD, Cr{sub 3}Ni{sub 5}Si{sub 2} crystals were identified at the interface by TEM.

  5. Manhattan Project Technical Series The Chemistry of Uranium (I) Chapters 1-10

    Energy Technology Data Exchange (ETDEWEB)

    Rabinowitch, E. I. [Argonne National Laboratory (ANL), Argonne, IL (United States); Katz, J. J. [Argonne National Laboratory (ANL), Argonne, IL (United States)

    1946-09-30

    This constitutes Chapters 1 through 10. inclusive, of The Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Nuclear Properties of Uranium; Properties of the Uranium Atom; Uranium in Nature; Extraction of Uranium from Ores and Preparation of Uranium Metal; Physical Properties of Uranium Metal; Chemical Properties of Uranium Metal; Intermetallic Compounds and Alloy systems of Uranium; the Uranium-Hydrogen System; Uranium Borides, Carbides, and Silicides; Uranium Nitrides, Phosphides, Arsenides, and Antimonides.

  6. Thin films and buried interfaces characterization with X-ray standing waves

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, S. [CNR, Rome (Italy). Istituto Elettronica Stato Solido

    1996-09-01

    The X-ray standing wave techniques is a powerful, non destructive method to study interfaces at the atomic level. Its basic features are described here together with the peculiarities of its applications to epitaxial films and buried interfaces. As examples of applications, experiments carried out on Si/silicide interfaces, on GaAs/InAs/GaAs buried interfaces and on Si/Ge superlattices are shown.

  7. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Hee (Clarendon Hills, IL); Natesan, Krishnamurti (Naperville, IL); Rink, David L. (Mokena, IL)

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  8. Influence of Si(111)-Cr surface phases in the formation and conductivity of Fe and Yb monolayers at room temperature on Si(111)

    Energy Technology Data Exchange (ETDEWEB)

    Galkin, N.G.; Goroshko, D.L.; Dotsenko, S.A.; Gouralnik, A.S.; Louchaninov, I.V

    2004-10-01

    Conductivity through the disordered iron and ytterbium two-dimensional layers during their formation on Si(111)-7x7, Si(111)7x7-Cr and Si(111)-({radical}3x{radical}3)/30 deg. -Cr surface phases was investigated. It was found in the case of Si(111)-7x7 surface that at submonolayer [1 monolayer (ML)=7.8x10{sup 18} at./m{sup 2} ] metal coverage iron and ytterbium atoms intermix with silicon surface atoms resulting in formation of silicide islands and silicide alloy layers which display the properties of a degenerated semiconductor. Deposition of small amounts (within one monolayer) of iron or ytterbium atoms onto the Si(111)-[({radical}3x{radical}3)/30 deg. ]-Cr surface phase results in growth of iron or ytterbium metal islands without formation of silicides. This fact indicates that this surface phase represents a diffusion barrier which blocks intermixing. It has been shown that metallic-type conductivity through the nearly continuous layer occurs at the coverage of 8.5 ML for Fe and 6.0 ML for Yb. For deposition of Fe or Yb atoms onto the Si(111)7x7-Cr surface phase, the 3D island growth mode without metallic-type layer conductivity was found within a coverage range extending up to 20-30 monolayers.

  9. Phase Evolution in and Creep Properties of Nb-Rich Nb-Si-Cr Eutectics

    Science.gov (United States)

    Gang, Florian; Kauffmann, Alexander; Heilmaier, Martin

    2017-10-01

    In this work, the Nb-rich ternary eutectic in the Nb-Si-Cr system has been experimentally determined to be Nb-10.9Si-28.4Cr (in at. pct). The eutectic is composed of three main phases: Nb solid solution (Nbss), β-Cr2Nb, and Nb9(Si,Cr)5. The ternary eutectic microstructure remains stable for several hundred hours at a temperature up to 1473 K (1200 °C). At 1573 K (1300 °C) and above, the silicide phase Nb9(Si,Cr)5 decomposes into α-Nb5Si3, Nbss, and β-Cr2Nb. Under creep conditions at 1473 K (1200 °C), the alloy deforms by dislocation creep while the major creep resistance is provided by the silicide matrix. If the silicide phase is fragmented and, thus, its matrix character is destroyed by prior heat treatment [e.g., at 1773 K (1500 °C) for 100 hours], creep is mainly controlled by the Laves phase β-Cr2Nb, resulting in increased minimum strain rates. Compared to state of the art Ni-based superalloys, the creep resistance of this three-phase eutectic alloy is significantly higher.

  10. A novel nanoscaled Schottky barrier based transmission gate and its digital circuit applications

    Science.gov (United States)

    Kumar, Sunil; Loan, Sajad A.; Alamoud, Abdulrahman M.

    2017-04-01

    In this work we propose and simulate a compact nanoscaled transmission gate (TG) employing a single Schottky barrier based transistor in the transmission path and a single transistor based Sajad-Sunil-Schottky (SSS) device as an inverter. Therefore, just two transistors are employed to realize a complete transmission gate which normally consumes four transistors in the conventional technology. The transistors used to realize the transmission path and the SSS inverter in the proposed TG are the double gate Schottky barrier devices, employing stacks of two metal silicides, platinum silicide (PtSi) and erbium silicide (ErSi). It has been observed that the realization of the TG gate by the proposed technology has resulted into a compact structure, with reduced component count, junctions, interconnections and regions in comparison to the conventional technology. The further focus of this work is on the application part of the proposed technology. So for the first time, the proposed technology has been used to realize various combinational circuits, like a two input AND gate, a 2:1 multiplexer and a two input XOR circuits. It has been observed that the transistor count has got reduced by half in a TG, two input AND gate, 2:1 multiplexer and in a two input XOR gate. Therefore, a significant reduction in transistor count and area requirement can be achieved by using the proposed technology. The proposed technology can be also used to perform the compact realization of other combinational and sequential circuitry in future.

  11. A study on the change in the phase transition temperature of TiSi sub 2 by adding the Zr element on different Si substrates

    CERN Document Server

    Yoon, S H

    1999-01-01

    The stabilization of C49 TiSi sub 2 at high temperature was investigated by adding Zr element to Ti-silicide both on single crystalline Si(100) and amorphous Si substrates. This stabilization of the C49 TiSi sub 2 phase, which exhibits lower surface and interface energies than those of the C54 TiSi sub 2 phase, was expected to suppress the problems of Ti-silicide, such as the phase transition and the agglomeration. Ti and Zr films of 40 nm were co-deposited on Si substrates in a dual e-beam evaporation system equipped with an ion pump and at a base pressure of approx 5x10 sup - sup 9 Torr. The amounts of Zr contents added to the Ti-silicide were 5, 10 and 20 atomic %, and the thicknesses were monitored by in-situ quartz-crystal thickness monitors. After the deposition, films were annealed by using an ex-situ vacuum furnace at temperatures between 600 .deg. C and 900 .deg. C in 100 .deg. C increments. The phase identification and the chemical compositions were investigated by X-ray diffraction (XRD) and Auger ...

  12. Electronic properties of new superconductors based on Ca(Al sub x Si sub 1 sub - sub x) sub 2 and Sr(Ga sub x Si sub 1 sub - sub x) sub 2 in crystal and nanotubular states

    CERN Document Server

    Shein, I R; Medvedeva, N I; Ivanovskij, A L

    2002-01-01

    The zone structures of the new Ca(Al sub x Si sub 1 sub - sub x) sub 2 and Sr(Ga sub x Si sub 1 sub - sub x) sub 2 layered superconductors (AlB sub 2 -type) are studied through the LMTO first-principle full-potential method. It is shown that the superconducting properties of the ternary silicides is conditioned by high density of the (Ca, Sr)d-states near the Fermi level, whereas the T sub C growth by the Sr(Ga sub x Si sub 1 sub - sub x) sub 2 -> Ca(Al sub x Si sub 1 sub - sub x) sub 2 transition is related to the increase in the photon frequencies due to the atoms mass decrease. Modeling the electron properties of the hypothetical (11, 11) and (20, 0) CaAlSi and SrGaSi nanotubes is accomplished. The silicide systems by transition from the crystalline to nanotubular state retain the metal-like properties. The template and film convolution methods may become the methods for obtaining the silicide nanotubes

  13. Studies on layer growth and interfaces on Ta-base thin layers by means of XPS; Untersuchungen zu Schichtwachstum und Grenzflaechen an Ta-basierten Duennschichten mittels XPS

    Energy Technology Data Exchange (ETDEWEB)

    Zier, M.

    2007-11-02

    In this thesis studies on the growth and on the formation of the interfaces of Ta and TaN layers on Si and SiO{sub 2} were performed. In the system TaN on SiO{sub 2} no reaction on the interface could be found. As the system with the mostly disturbed interface Ta on SiO{sub 2} was proved. Here a reduction of the SiO{sub 2} at simultaneous oxidation of the Ta was to be observed. Additionally tantalum silicide was formed to be considered concerning the bonding state as Ta{sub 5}Si{sub 3}, from which a double layer of a tantalum silicide and a tantalum suboxide resulted. A whole thickness of the double layer of above 1 nm resulted. In the system Ta on Si at the deposition of the film on the interface a tantalum silicide was formed to be characterized concerning the bonding state as TaSi{sub 2}. The thickness of the interlayer growed thereby up to 0.8 nm in form of islands. Finally in the system TaN on Si a silicon nitride formation during the deposition was observed, which was attributed to the insertion of adsorbed nitrogen from the sputtering atmosphere by recoil implantation of the sputtered Ta atoms. The silicon nitride interlayer growed thereby up to a thickness of 0.8 nm.

  14. Influence of Powder Metallurgical Processing Routes on Phase Formations in a Multicomponent NbSi-Alloy

    Science.gov (United States)

    Seemüller, C.; Hartwig, T.; Mulser, M.; Adkins, N.; Wickins, M.; Heilmaier, M.

    2014-09-01

    Refractory metal silicide composites on the basis of Nbss-Nb5Si3 have been investigated as potential alternatives for nickel-base superalloys for years because of their low densities and good high-temperature strengths. NbSi-based composites are typically produced by arc-melting or casting. Samples in this study, however, were produced by powder metallurgy because of the potential for near net-shape component fabrication with very homogeneous microstructures. Either gas atomized powder or high-energy mechanically alloyed elemental powders were compacted by powder injection molding or hot isostatic pressing. Heat treatments were applied for phase stability evaluation. Slight compositional changes (oxygen, nitrogen, or iron) introduced by the processing route, i.e., powder production and consolidation, can affect phase formations and phase transitions during the process. Special focus is put on the distinction between different silicides (Nb5Si3 and Nb3Si) and silicide modifications (α-, β-, and γ-Nb5Si3), respectively. These were evaluated by x-ray diffraction and energy-dispersive spectroscopy measurements with the additional inclusion of thermodynamic calculations using the calculated phase diagram method.

  15. Design and optimization of high-performance slot-microring Si-photodetector based on internal photoemission effect

    Science.gov (United States)

    Hosseinifar, Mitra; Ahmadi, Vahid; Ebnali-Heidari, Majid

    2017-08-01

    This paper presents the design and optimization of a microring resonator enhanced-internal photoemission effect-photodetectors (MRRE-IPE-PDs) suitable for optical communication. Two PD configurations are considered: the first consists of an MRR that is partially surrounded by a nanolayer of silicide with a single Schottky barrier on p-Si MRR; and the second consists of a silicide film buried in the width midpoints of a Si-based MRR where photoemission occurs over the two Schottky barriers. Several silicides are considered for the stripe (PtSi, Pd2Si, TaSi2 and CoSi2). The important features of the device, such as quantum efficiency (QE), responsivity, CW sensitivity and dark current are discussed and the trade-off between 3 dB bandwidth and QE are analyzed for nanoscaled absorption layer. In this regard, some design curves are presented for the optimized MRRE-IPE-PDs. Additionally, this paper reveals substantial improvement via comparisons with QE and responsivity measurements reported in the literature. Bandwidth-efficiency product of 61-71 GHz, responsivities of 0.8-0.9 and QE of 64-71% and the minimum receiver sensitivity of -65 to -66 dBm are also predicted for single and double Schottky barriers, respectively.

  16. Photoemission study of the initial stage of Er/Si(100) interface formation

    CERN Document Server

    Chen Gang; Li Zhe Shen; Wang Xun

    2002-01-01

    The initial stage of Er/Si(100) interface formation has been investigated by using synchrotron radiation photoelectron spectroscopy combined with low-energy electron diffraction. Both the valence band and the core level peaks of the Si photoemission spectra shift rigidly with increasing Er coverage in the submonolayer region. Upon depositing 0.6 monolayers of Er on the Si(100) surface at room temperature, the surface Fermi level is ultimately pinned at 0.29 eV above its initial value, which is equivalent to a Schottky barrier height of 0.67 eV. No evidence is found for the formation of Er silicides at the as-deposited surfaces. Annealing of the Er-covered Si(100) surfaces at 600 deg. C results in the appearance of a new peak located 1.2 eV below the Si 2p peak, indicating the presence of some sort of Er silicide. Meanwhile, the Er 4f spectrum measured for samples upon annealing exhibits a well-resolved fine structure, implying that only monospecies of Er silicide may exist on the surface.

  17. A Vacuum Encapsulated Lateral FED with Various Cathode Materials

    Science.gov (United States)

    Park, Cheol-Min; Lim, Moo-Sup; Han, Min-Koo

    We have fabricated poly-Si, Si, and Ti-silicide field emitter arrays employing in-situ vacuum encapsulated lateral field emitter structures and investigated the field emission characteristics such as turn-on voltage, emission current density, and the stability of the emission current. Although poly-Si and Si emitter exhibit almost identical turn-on voltages, the Si emitter shows a sharp turn-on characteristic compared with the poly-Si emitter. It may be caused by the uniform surface of the Si emitter. The current densities of poly-Si, and Si emitter are 0.47, 0.43μA/tip respectively when the anode to cathode voltage is 90V. The turn-on voltage and current density of the Ti-silicide emitter are about 31V, and 1.81μA/tip at a VAK of 90V. The normalized current fluctuations shows that the Ti-silicide emitter exhibits the most stable current.

  18. Materials characterization of rapid thermal chemical vapor deposition of titanium disilicide

    Science.gov (United States)

    Gladden-Green, Dannellia Banay

    Technological advancements of novel processes and materials involving refractory metal silicides for ultra large scale integration is of paramount importance to the semiconductor industry. Scaling of devices to meet the demands for increased packing density and speed requires such novel processes and materials. Rapid thermal chemical vapor deposition (RTCVD) of titanium disilicide (TiSisb2) was investigated in an effort to meet some of the challenges of ultra large scale integration (ULSI) technology. Selective RTCVD of TiSisb2 offers an optimal technological vehicle for achieving contacts to ultra-shallow junctions. Of all of the metal silicides, TiSisb2 has the lowest resistivity and meets the microelectronics demands for a thermally stable contact. The research results presented in this dissertation explores the mechanisms of selective RTCVD of TiSisb2 in terms of thermodynamic trends and kinetic driving forces for nucleation and growth. The present research addresses the qualitative and quantitative parameters that affect the controlling mechanisms for nucleation and therefore the results provide significant data and theoretical insights into a state-of-the-art process. Just as the fundamental building block in understanding the kinetic constraints of a process lie in the realm of thermodynamic exploration, understanding the complex processes involved in RTCVD TiSisb2 begin with characterization of the mechanisms governing thin film nucleation. In this work, the early stages of growth are investigated as they offer insight into how process parameters are optimized to render desired silicide film properties. Equilibrium simulations have been used to model the CVD reaction with very good trend indicating accuracy. Empirical investigations of CVD TiSisb2 took place in a low-pressure rapid-thermal environment using the SiHsb4 + TiClsb4 gas system on silicon (100) substrates. Secondary ion mass spectroscopy (SIMS) has been used to qualify the benefits of vacuum and

  19. Microstructural and mechanical characterization of Nb-based in situ composites from Nb-Si-Ti ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z. [Department of Mechanics and Mechanical Engineering, CAS Key Laboratory for Mechanical Behavior and Design of Materials, School of Engineering Science, University of Science and Technology of China, Hefei 230026, Anhui (China); Peng, L.M. [Department of Mechanics and Mechanical Engineering, CAS Key Laboratory for Mechanical Behavior and Design of Materials, School of Engineering Science, University of Science and Technology of China, Hefei 230026, Anhui (China)], E-mail: penglm@ustc.edu.cn

    2007-11-15

    This study deals with the Nb-niobium silicide-based composites developed by the hot-pressing of Nb-Si-Ti ternary powder mixtures with a fixed Ti addition (6 at.%) and Si content ranging from hypereutectic (11 at.%) to near-eutectic compositions (18 at.%). The effects of Si content, Ti addition and strain rates on the sample microstructural characterization, flexural strength, fracture toughness, quasi-static compressive deformation and failure processes were investigated. It was revealed that the volume fraction of silicides increased with increasing Si content, and most of the Ti atoms dissolved into the niobium silicides to form (Nb,Ti){sub 5}Si{sub 3} solid solutions instead of binary titanium silicides. The experimental evidence showed that a moderate improvement in the flexural strength, fracture toughness and compressive yield stress of the composites was achieved by the addition of Ti. Higher Si additions produced a much more remarkable enhancement in the compressive yield stress and bulk hardness, whereas both the flexural strength and fracture toughness decreased with increasing Si content owing to the existence of residual porosities in the samples. The composites showed remarkable superiority to the arc-melted Nb-Si alloys and monolithic niobium silicides in fracture toughness (8.3-13.0MPa{radical}(m) vs. 4.5MPa{radical}(m)), where the toughening effect was attributed mainly to crack bridging and crack deflection by the remaining ductile Nb phase. Moreover, quasi-static uniaxial compression tests at strain rates between 10{sup -5} and 10{sup -3} s{sup -1} indicated that the deformation behavior and failure processes were significantly affected by Si content and strain rates. The strain-rate-hardening behavior for all the strain rates was observed in the composite materials and the strain-rate sensitivity decreased with increasing Si content. At a lower strain rate, the composite materials with a hypoeutectic Si composition failed with a pseudoplastic

  20. A statistical analysis of the initial biodistribution of {sup 153}Sm-EDTMP in a canine

    Energy Technology Data Exchange (ETDEWEB)

    Galiano, Eduardo [Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ont., P3E 2C6 (Canada)]. E-mail: egalianoriveros@laurentian.ca; Stradiotto, Marco [Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ont., P3E 2C6 (Canada)

    2005-07-01

    {sup 153}Sm (t{sub 1/2}=46h) emits a 103keV gamma photon and two medium-energy beta particles. Five mCi of Samarium-153 ethylenediaminetetramethylenephosphonic acid ({sup 153}Sm-EDTMP) were administered to a clinically normal dog and whole body scans were obtained at 15min, 2h, and 24h post-injection (PI). Regions of interest (ROIs) were drawn representing abdomen, knee, rib, vertebral bodies, bladder, kidney, and liver, in each image. For each ROI, the mean intensity and standard deviation were computed, and a histogram was created. Clinically significant increased uptakes were found in liver and kidney.

  1. Coprecipitation experiment with Sm hydroxide using a multitracer produced by nuclear spallation reaction: A tool for chemical studies with superheavy elements.

    Science.gov (United States)

    Kasamatsu, Yoshitaka; Yokokita, Takuya; Toyomura, Keigo; Shigekawa, Yudai; Haba, Hiromitsu; Kanaya, Jumpei; Huang, Minghui; Ezaki, Yutaka; Yoshimura, Takashi; Morita, Kosuke; Shinohara, Atsushi

    2016-12-01

    To establish a new methodology for superheavy element chemistry, the coprecipitation behaviors of 34 elements with samarium hydroxide were investigated using multitracer produced by a spallation of Ta. The chemical reactions were rapidly equilibrated within 10s for many elements. In addition, these elements exhibited individual coprecipitation behaviors, and the behaviors were qualitatively related to their hydroxide precipitation behaviors. It was demonstrated that the ammine and hydroxide complex formations of superheavy elements could be investigated using the established method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Radiological response of lanthanum guiding seeds in brachytherapy implants; Resposta radiologica de sementes guia de lantanio em implantes braquiterapicos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.S.R.; Machado, E.D.P., E-mail: lais26@globo.com [Centro Federal de Educacao Tecnologica de Minas Gerais, Belo Horizonte, MG (Brazil). Departamento de Engenharia de Materiais; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Roberto, W.S. [Centro Federal de Educacao Tecnologica de Minas Gerais, Belo Horizonte, MG (Brazil). Departamento de Fisica e Matematica

    2013-08-15

    Ceramic seeds with La-139 incorporated were synthesized to be used as radiological guides in brachytherapy implants. The synthesis was performed based on the sol-gel method. The seeds were subjected to characterization by Scanning Electron Microscopy, X-ray diffraction and Energy-Dispersive X-ray Spectroscopy. Furthermore, the contrast from a radiographic film was evaluated to lanthanum, samarium and holmium seeds. Radiological response on a phantom at different depths with lanthanum seeds and metal seeds was also investigated. Based on the values of contrast, the synthesized lanthanum seeds can be considered efficient as radiological guides when implanted together with pure Ho-165 and Sm-152 seeds. (author)

  3. Understanding the photoluminescence characteristics of Eu{sup 3+}-doped double-perovskite by electronic structure calculation

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Binita [St. Paul’s Cathedral Mission College, 33/1Raja Rammohan Roy Road, Kolkata 700009 (India); Halder, Saswata; Sinha, T. P. [Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009 (India); Das, Sayantani [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)

    2016-05-23

    Europium-doped luminescent barium samarium tantalum oxide Ba{sub 2}SmTaO{sub 6} (BST) has been investigated by first-principles calculation, and the crystal structure, electronic structure, and optical properties of pure BST and Eu-doped BST have been examined and compared. Based on the calculated results, the luminescence properties and mechanism of Eu-doped BST has been discussed. In the case of Eu-doped BST, there is an impurity energy band at the Fermi level, which is formed by seven spin up energy levels of Eu and act as the luminescent centre, which is evident from the band structure calculations.

  4. Geochronology and structuring of the Ceara State: Borborema Province northwestern part, NE Brazil; Geocronologia e estruturacao do estado do Ceara: NW da provincia Borborema, NE, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Fetter, A.; Van Schmus, W.R. [Kansas Univ., Lawrence, KS (United States). Dept. of Geology; Santos, Ticiano J. Saraiva dos [UNESP, Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas; Arthaud, M.; Nogueira Neto, J. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Geologia

    1997-12-31

    The work confirms that the geochronological new data U/Pb in zircon and Samarium/Neodymium from the Ceara State furnished a refined chronology of the geological activity in the NW part of the Borborema Province, indicating an evolutive history since 2,78 Ga and 532 Ma. Furthermore, these data facilitated the different crust domain outlines in the region, putting age maximum limits in the pre-brasilianas supracrusts rocks deposition, and evidencing the epoch and duration of the Brasiliano magmatism and metamorphism in the northwest part of the State

  5. Structural aspects of displacive transformations: what can optical microscopy contribute? Dehydration of Sm2(C2O43·10H2O as a case study

    Directory of Open Access Journals (Sweden)

    Alexander A. Matvienko

    2017-09-01

    Full Text Available For martensitic transformations the macroscopic crystal strain is directly related to the corresponding structural rearrangement at the microscopic level. In situ optical microscopy observations of the interface migration and the change in crystal shape during a displacive single crystal to single crystal transformation can contribute significantly to understanding the mechanism of the process at the atomic scale. This is illustrated for the dehydration of samarium oxalate decahydrate in a study combining optical microscopy and single-crystal X-ray diffraction.

  6. Synthesis and application of a new fluorous-tagged ammonia equivalent

    DEFF Research Database (Denmark)

    Nielsen, Simon Dalsgaard; Smith, Garrick; Begtrup, Mikael

    2010-01-01

    A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope of...... of the fluorous N--O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity....

  7. Synthesis and application of a new fluorous-tagged ammonia equivalent.

    Science.gov (United States)

    Nielsen, Simon D; Smith, Garrick; Begtrup, Mikael; Kristensen, Jesper L

    2010-04-19

    A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope of the fluorous N-O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Jaderné kolektivní stupně volnosti a Skyrme funkcionál

    OpenAIRE

    Božík, Daniel

    2010-01-01

    Title: Energy functional theories in nuclear physics Author: Daniel Božík Department: Institute of Particle and Nuclear Physics of Charles University Supervisor: prof. RNDr. Jan Kvasil, DrSc. Supervisor's e-mail address: Abstract: In the present work we study the giant resonances of the chain of even-even samarium nuclei 144−154 Sm. The numerical calculations are provided by a chain of numer- ical codes. Mean field is calculated by the HFB method for the Skyrme d...

  9. Geochronology Intermediary Laboratory implantation at the Rio Grande do Norte Federal University: the dating of the Serrinha Granitoid (RN) and the correlate Brasiliana extensional deformation; Implantacao do Laboratorio Intermediario de Geocronologia na UFRN: a datacao do granitoide de Serrinha (RN) e da deformacao extensional brasiliana correlata

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Maria Helena F.; Sa, Emanuel F. Jardim de; Souza, Zorano S. [Pernambuco Univ., Recife, PE (Brazil). Nucleo de Pesquisa em Geodinamica e Geofisica; Mendes, Franklin S. [Pernambuco Univ., Recife, PE (Brazil). Curso de Quimica; Ramalho, Karlos A.C. [Pernambuco Univ., Recife, PE (Brazil). Curso de Geologia

    1997-12-31

    The article describes the activities developed by the Geochronology Intermediary Laboratory at the Federal University of the Rio Grande do Norte, a Brazilian university, where there were the preoccupation of establishing strategies for a geochronological development. It relates the Rubidium-Strontium (Rb/Sr) and Samarium-Neodymium (Sm/Nd) methods, describing the analysis realized in these methodologies. Afterward, it presents the geological and petrographic situation of the Granitoide de Serrinha, located at Rio Grande do Norte State, Brazil and its geochronological data 8 refs., 2 figs.

  10. ACR-ASTRO practice guideline for the performance of therapy with unsealed radiopharmaceutical sources.

    Science.gov (United States)

    Henkin, Robert E; Del Rowe, John D; Grigsby, Perry W; Hartford, Alan C; Jadvar, Hossein; Macklis, Roger M; Parker, J Anthony; Wong, Jeffrey Y C; Rosenthal, Seth A

    2011-08-01

    This guideline is intended to guide appropriately trained and licensed physicians performing therapy with unsealed radiopharmaceutical sources. Adherence to this guideline should help to maximize the efficacious use of these procedures, maintain safe conditions, and ensure compliance with applicable regulations. The topics dealt with in this guideline include indications for the use of iodine-131, both for the treatment of hyperthyroidism and thyroid carcinoma. In addition, indications for other less common procedures include those for the use of phosphorous-32 in its liquid and colloidal forms, strontium-89, samarium-153, and the use of Y-90 antibodies.

  11. Accumulation of rare earth elements by siderophore-forming Arthrobacter luteolus isolated from rare earth environment of Chavara, India.

    Science.gov (United States)

    Emmanuel, E S Challaraj; Ananthi, T; Anandkumar, B; Maruthamuthu, S

    2012-03-01

    In this study, Arthrobacter luteolus, isolated from rare earth environment of Chavara (Quilon district, Kerala, India), were found to produce catechol-type siderophores. The bacterial strain accumulated rare earth elements such as samarium and scandium. The siderophores may play a role in the accumulation of rare earth elements. Catecholate siderophore and low-molecular-weight organic acids were found to be present in experiments with Arthrobacter luteolus. The influence of siderophore on the accumulation of rare earth elements by bacteria has been extensively discussed.

  12. Synthesis of 2-(9,10-Dihydro-9,10-propanoanthracen-9-yl-N-methylethanamine via a [4+2] Cycloaddition

    Directory of Open Access Journals (Sweden)

    Usama Karama

    2010-06-01

    Full Text Available The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl-N-methylethanamine(2as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl-N-methylmethaneamine (1 was described. The key intermediate 9-(prop-2-en-1-yl-9,10-dihydro-9,10-propanoanthracen-12-one (7was successfully synthesized via a [4+2] cycloaddition of α-bromoacrolein and 9-allyl-anthracene, followed by ring expansion and samarium diiodide deoxygenation.

  13. Synthesis of 2-(9,10-dihydro-9,10-propanoanthracen-9-yl)-N-methylethanaminevia a [4+2] cycloaddition.

    Science.gov (United States)

    Karama, Usama; Al-Saidey, Adel; Al-Othman, Zeid; Almansour, Abdel Rahman

    2010-06-09

    The synthesis of the tetracyclic molecule 2-(9,10-dihydro-9,10-propano-anthracen-9-yl)-N-methylethanamine (2) as a homologue of the antidepressant 1-(9,10-dihydro-9,10-ethanoanthracen-9-yl)-N-methylmethaneamine (1) was described. The key intermediate 9-(prop-2-en-1-yl)-9,10-dihydro-9,10-propanoanthracen-12-one (7) was successfully synthesized via a [4+2] cycloaddition of alpha-bromoacrolein and 9-allyl-anthracene, followed by ring expansion and samarium diiodide deoxygenation.

  14. SPECTROSCOPIC PROPERTIES OF THE Ln-Ge COMPLEXES WITH DIETHYLENETRIAMINEPENTAACETIC ACID

    Directory of Open Access Journals (Sweden)

    Sergiy Smola

    2007-06-01

    Full Text Available Four new heteronuclear lanthanide complexes with general formula [Ge(OH(μ-HDTPALnGe(OH (μ-DTPA] (Ln = Sm – Dy were synthesized and subsequently characterized by different physico- chemical methods. The structures of new compounds have been proposed. In considered complexes the 4f-luminescence of three-charged ions of samarium, europium, terbium and dysprosium is realized at UV-excitation. It is noteworthy that it is the first observation of 4f-luminescence in water solutions of heteronuclear f-p-complexes. The comparison of luminescent characteristics of hetero- and homonuclear landthanide complexes is described and discussed as well.

  15. Die selfverstaan van die Samaritane soos dit uit- drukking vind in die feesliturgie צלות מוצד השמיני

    Directory of Open Access Journals (Sweden)

    J. Beyers

    1999-01-01

    Full Text Available The self-understanding of the Samaritans, as expressed in the liturgy of the צלות מוצד השמיני festivalThis study is concerned with the identity and religion of the Samaritans. The way in which the Samaritans understood their identity is highlighted by their perception of God, by the traditions they adhered to and by the selection of texts from the Pentateuch they used in their liturgy. The beliefs and rituals of the Samarium faith found their way into the Samaritan Liturgy. The study of a part of the Samaritan Liturgy shows that the Samaritans are heirs to the religion of the northern tibes of Israel.

  16. Development of atomic spectroscopy technology -Development of ultrasensitive spectroscopic analysis technology

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Hyung Kee; Song Kyoo Suk; Kim, Duk Hyun; Hong, Suk Kyung; Lee, Yong Joo; Lee, Jong Hoon; Yang, Kee Hoh [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    For the resonance ionization spectroscopy experiment, erbium and samarium were chosen as test elements and their optimum photoionization schemes for trace analysis have been investigated by using multiphoton spectroscopic techniques. With the optimum scheme, the detection limit of various atoms were measured. For the test of laser induced fluorescence system, calibration curves obtained from lead and cadmium standard solutions were made and Pb concentrations of various unknown solutions were determined. By using the developed differential absorption lidar system, backscattering signals from aerosol and ozone have been measured. Error source, error calibration and data interpretation techniques have been also studied. 60 figs, 8 pix, 28 tabs, 30 refs. (Author).

  17. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Phuoc [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State; Mcintyre, Dustin [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United State

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  18. Giant magneto resistance and temperature coefficient of resistance in Sm0.55Sr0.30Ag0.15MnO3 perovskite

    OpenAIRE

    Bhat, Masroor Ahmad; Zargar, Rayees A.; Modi, Anchit; Arora, Manju; Gaur, N K

    2016-01-01

    Silver ions substituted samarium strontium manganite (Sm0.55Sr0.30Ag0.15MnO3) pervoskite was synthesized by using respective oxides in stoichiometric ratio through solid state reaction. The as-prepared sample was characterized by various analytical techniques to confirm its formation and understand the effect of monovalent silver ions in pervoskite lattice. X-ray diffraction pattern confirms the single phase formation while grain morphology in SEM image indicates good connectivity among the g...

  19. The ternary system: Silicon-tantalum-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rogl, Peter, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria); Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France)

    2010-09-01

    Phase equilibria in the ternary system Si-Ta-U have been established in an isothermal section at 1000 {sup o}C by optical microscopy, electron probe microanalysis and X-ray diffraction. Two novel ternary compounds were observed and were characterised by X-ray powder Rietveld refinement: stoichiometric {tau}{sub 1}-U{sub 2}Ta{sub 3}Si{sub 4} (U{sub 2}Mo{sub 3}Si{sub 4}-type, P2{sub 1}/c; a = 0.70011(1), b = 0.70046(1), c = 0.68584(1) nm, ss = 109.38(1); R{sub F} = 0.073, X-ray powder Rietveld refinement) and {tau}{sub 2}-U{sub 2-x}Ta{sub 3+x}Si{sub 4} at x {approx} 0.30 (Sc{sub 2}Re{sub 3}Si{sub 4}-type = partially ordered Zr{sub 5}Si{sub 4}-type, P4{sub 1}2{sub 1}2; a = b = 0.69717(3)(1), c = 1.28709(4) nm; R{sub F} = 0.056; X-ray single crystal data). Mutual solubility of U-silicides and Ta-silicides are found to be very small i.e. below about 1 at.%. Due to the equilibrium tie-line Ta{sub 2}Si-U(Ta), no compatibility exists between the U-rich silicides U{sub 3}Si or U{sub 3}Si{sub 2} and tantalum metal. Single crystals obtained from alloys slowly cooled from liquid (2000 {sup o}C), yielded a fully ordered compound U{sub 2}Ta{sub 2}Si{sub 3}C (unique structure type; Pmna, a = 0.68860(1); b = 2.17837(4); c = 0.69707(1) nm; R{sub F2} = 0.048).

  20. Review of SiGe HBTs on SOI

    Science.gov (United States)

    Mitrovic, I. Z.; Buiu, O.; Hall, S.; Bagnall, D. M.; Ashburn, P.

    2005-09-01

    This paper reviews progress in SiGe Heterojunction Bipolar Transistors (HBT) on Silicon-On-Insulator (SOI) technology. SiGe HBTs on SOI are attractive for mixed signal radio frequency (RF) applications and have been of increasing research interest due to their compatibility with SOI CMOS (Complementary Metal Oxide Semiconductor) technology. In bipolar technology, the use of SOI substrate eliminates parasitic substrate transistors and associated latch-up, and has the ability to reduce crosstalk, particularly when combined with buried groundplanes (GP). Various technological SOI bipolar concepts are reviewed with special emphasis on the state-of-the-art SOI SiGe HBT devices in vertical and lateral design. More in depth results are shown from a UK consortium advanced RF platform technology, which includes SOI SiGe HBTs. Bonded wafer technology was developed to allow incorporation of buried silicide layers both above and below the buried oxide. New electrical and noise characterisation results pointed to reduced 1/ f noise in these devices compared to bulk counterparts. The lower noise is purported to arise from strain relief of the device structure due to the elasticity of the buried oxide layer during the high temperature epitaxial layer growth. The novel concept of the silicide SOI (SSOI) SiGe HBT technology developed for targeting a reduction in collector resistance, as well as for suppressing the crosstalk, is outlined. The buried tungsten silicide layers were found to have negligible impact on junction leakage. Further to vertical SiGe HBTs on SOI, the challenges of fabricating a lateral SOI SiGe HBT structure are presented.

  1. Diagenetically altered fossil micrometeorites suggest cosmic dust is common in the geological record

    Science.gov (United States)

    Suttle, Martin D.; Genge, Matthew J.

    2017-10-01

    We report the discovery of fossil micrometeorites from Late Cretaceous chalk. Seventy-six cosmic spherules were recovered from Coniacian (87 ± 1 Ma) sediments of the White Chalk Supergroup. Particles vary from pristine silicate and iron-type spherules to pseudomorphic spherules consisting of either single-phase recrystallized magnetite or Fe-silicide. Pristine spherules are readily identified as micrometeorites on the basis of their characteristic mineralogies, textures and compositions. Both magnetite and silicide spherules contain dendritic crystals and spherical morphologies, testifying to rapid crystallisation of high temperature iron-rich metallic and oxide liquids. These particles also contain spherical cavities, representing weathering and removal of metal beads and irregular cavities, representing vesicles formed by trapped gas during crystallization; both features commonly found among modern Antarctic Iron-type (I-type) cosmic spherules. On the basis of textural analysis, the magnetite and Fe-silicide spherules are shown to be I-type cosmic spherules that have experienced complete secondary replacement during diagenesis (fossilization). Our results demonstrate that micrometeorites, preserved in sedimentary rocks, are affected by a suite of complex diagenetic processes, which can result in disparate replacement minerals, even within the same sequence of sedimentary beds. As a result, the identification of fossil micrometeorites requires careful observation of particle textures and comparisons with modern Antarctic collections. Replaced micrometeorites imply that geochemical signatures the extraterrestrial dust are subject to diagenetic remobilisation that limits their stratigraphic resolution. However, this study demonstrates that fossil, pseudomorphic micrometeorites can be recognised and are likely common within the geological record.

  2. Ultra-reduced phases in Apollo 16 regolith: Combined field emission electron probe microanalysis and atom probe tomography of submicron Fe-Si grains in Apollo 16 sample 61500

    Science.gov (United States)

    Gopon, Phillip; Spicuzza, Michael J.; Kelly, Thomas F.; Reinhard, David; Prosa, Ty J.; Fournelle, John

    2017-09-01

    The lunar regolith contains a variety of chemically reduced phases of interest to planetary scientists and the most common, metallic iron, is generally ascribed to space weathering processes (Lucey et al. ). Reports of silicon metal and iron silicides, phases indicative of extremely reducing conditions, in lunar samples are rare (Anand et al. ; Spicuzza et al. ). Additional examples of Fe-silicides have been identified in a survey of particles from Apollo 16 sample 61501,22. Herein is demonstrated the utility of low keV electron probe microanalysis (EPMA), using the Fe Ll X-ray line, to analyze these submicron phases, and the necessity of accounting for carbon contamination. We document four Fe-Si and Si0 minerals in lunar regolith return material. The new Fe-Si samples have a composition close to (Fe,Ni)3Si, whereas those associated with Si0 are close to FeSi2 and Fe3Si7. Atom probe tomography of (Fe,Ni)3Si shows trace levels of C (60 ppma and nanodomains enriched in C, Ni, P, Cr, and Sr). These reduced minerals require orders of magnitude lower oxygen fugacity and more reducing conditions than required to form Fe0. Documenting the similarities and differences in these samples is important to constrain their formation processes. These phases potentially formed at high temperatures resulting from a meteorite impact. Whether carbon played a role in achieving the lower oxygen fugacities—and there is evidence of nearby carbonaceous chondritic material—it remains to be proven that carbon was the necessary component for the unique existence of these Si0 and iron silicide minerals.

  3. Synergistic Effects of Sm and C Co-Doped Mixed Phase Crystalline TiO₂ for Visible Light Photocatalytic Activity.

    Science.gov (United States)

    Peng, Fuchang; Gao, Honglin; Zhang, Genlin; Zhu, Zhongqi; Zhang, Jin; Liu, Qingju

    2017-02-21

    Mixed phase TiO₂ nanoparticles with element doping by Sm and C were prepared via a facile sol-gel procedure. The UV-Vis light-diffuse reflectance spectroscopy analysis showed that the absorption region of co-doped TiO₂ was shifted to the visible-light region, which was attributed to incorporation of samarium and carbon into the TiO₂ lattice during high-temperature reaction. Samarium effectively decreased the anatase-rutile phase transformation. The grain size can be controlled by Sm doping to achieve a large specific surface area useful for the enhancement of photocatalytic activity. The photocatalytic activities under visible light irradiation were evaluated by photocatalytic degradation of methylene blue (MB). The degradation rate of MB over the Sm-C co-doped TiO₂ sample was the best. Additionally, first-order apparent rate constants increased by about 4.3 times compared to that of commercial Degusssa P25 under the same experimental conditions. Using different types of scavengers, the results indicated that the electrons, holes, and •OH radicals are the main active species for the MB degradation. The high visible-light photocatalytic activity was attributed to low recombination of the photo-generated electrons and holes which originated from the synergistic effect of the co-doped ions and the heterostructure.

  4. Molecular electrophosphorescence in (Sm, Gd)-{beta}-diketonate complex blend for OLED applications

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, R., E-mail: fisicaplic@hotmail.com [Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, UNI, Av. Tupac Amaru 210, Lima 31, Peru (Peru); Cremona, M. [DIMAT - Divisao de Metrologia de Materiais, Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial, INMETRO, Duque de Caxias, RJ (Brazil); Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, PUC-Rio, C.P. 38071, Rio de Janeiro, RJ, CEP 22453-970 (Brazil); Teotonio, E.E.S. [Departamento de Quimica, CCEN, Universidade Federal da Paraiba, UFPB, C.P. 5093, Joao Pessoa, PB, CEP 5805-970 (Brazil); Brito, H.F. [Instituto de Quimica, Universidade de Sao Paulo, USP, C.P. 26077, Sao Paulo, SP, CEP 05599-970 (Brazil); Malta, O.L. [Departamento de Quimica Fundamental, CCEN, Universidade Federal de Pernambuco, Cidade Universitaria, Recife, PE, CEP 50670-901 (Brazil)

    2013-02-15

    In this work the preparation and characterization of the triple-layer organic light-emitting diode (OLED) using a mixture of the samarium and gadolinium {beta}-diketonate complexes [Sm{sub 0.5}Gd{sub 0.5}(TTA){sub 3}(TPPO){sub 2}] as emitting layer is reported. The OLED's devices contain 1-(3-methylphenyl)-1,2,3,4-tetrahydroquinoline-6-carboxyaldehyde-1, 1'-diphenylhydrazone (MTCD) as hole-transporting layer and tris(8-hydroxyquinoline aluminum) (Alq{sub 3}) as electron transporting layer. The electroluminescence spectrum present emission narrow bands from the {sup 4}G{sub 5/2}{yields}{sup 6}H{sub J} transitions (where J=5/2, 7/2 and 9/2) characteristic of the Sm{sup 3+} ion. These sharp lines are overlapped with a broad band attributed to the electrophosphorescence from the T{sub 1}{yields}S{sub 0} transition in the ligand TTA. The intramolecular energy transfer is discussed and applied on the change of the emission color of the organic LEDs at different bias voltages. - Highlights: Black-Right-Pointing-Pointer Samarium and gadolinium complexes. Black-Right-Pointing-Pointer OLED with complex blend (Sm,Gd). Black-Right-Pointing-Pointer Electrophosphorescence emission detection. Black-Right-Pointing-Pointer Application in OLED changing the color emission.

  5. Spontaneous and stimulated emission in Sm{sup 3+}-doped YAl{sub 3}(BO{sub 3}){sub 4} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ryba-Romanowski, Witold [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Lisiecki, Radosław, E-mail: R.Lisiecki@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Beregi, Elena [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary); Martín, I.R. [Departamento de Física, Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, 38206 S/C de Tenerife, Laguna (Spain)

    2015-11-15

    Single crystals of YAl{sub 3}(BO{sub 3}){sub 4} doped with trivalent samarium were grown by the top-seeded high temperature solution method and their absorption and emission spectra were investigated. Optical pumping into prominent absorption band around 405 nm feeds the {sup 4}G{sub 5/2} metastable level giving rise to intense visible luminescence distributed in several spectral lines with the most intense line around 600 nm characterized by a branching ratio of 0.42 and peak emission cross section of 0.25×10{sup −20} cm{sup 2}. Optical amplification at 600 nm with a gain coefficient of 2.9 cm{sup −1} was achieved during a pump-and-probe experiment. - Highlights: • YAB:Sm crystal grown by the top-seeded high temperature solution method. • Spectroscopic qualities relevant for visible laser operation. • YAB:Sm single crystal used in a pump-and-probe experiment. • Optical amplification properties of samarium doped YAl{sub 3}(BO{sub 3}){sub 4}.

  6. Synthesis of Sm2(WO4)3 nanocrystals via a statistically optimized route and their photocatalytic behavior

    Science.gov (United States)

    Mahdi Pourmortazavi, Seied; Rahimi-Nasrabadi, Mehdi; Aghazadeh, Mustafa; Ganjali, Mohammad Reza; Sadeghpour Karimi, Meisam; Norouzi, Parviz

    2017-03-01

    The application of a Taguchi approach to the optimization of the precipitation reaction between Sm3+ and {{{{WO}}}{{4}}}2- as a rapid procedure for the preparation of Sm2(WO4)3 nanoparticles as a photocatalyst is evaluated. The effect of the prominent operating factors on the product are evaluated so as to yield the best synthesis conditions, leading to the finest product particles of the desired morphologies, which can turn the rather primitive precipitation reaction into a powerful tool for the preparation of nanostructured crystals of insoluble salts. The effects of the alteration of the studied factors on the final properties of the product are further evaluated through characterization techniques, including x-ray diffraction, energy-dispersive x-ray analysis, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results of the study, together with the analysis of variance operations, revealed that through the control of samarium and tungstate concentrations, and temperature, considerable results can be achieved in terms of the product dimensions, morphology, purity and structure. Moreover, the photocatalytic behavior of the synthesized samarium tungstate nanoparticles for the photocatalytic degradation of methylene blue under ultraviolet light is investigated and compared with titanium dioxide as a well-known photocatalyst.

  7. High-pressure synthesis and exotic heavy-fermion behaviour of the filled skutterudite SmPt{sub 4}Ge{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Gumeniuk, R; Leithe-Jasper, A; Schnelle, W; Nicklas, M; Rosner, H; Ormeci, A; Burkhardt, U; Schmidt, M; Schwarz, U; Grin, Yu [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Strasse 40, 01187 Dresden (Germany); Schoeneich, M; Ruck, M, E-mail: schnelle@cpfs.mpg.d [Anorganische Chemie, Technische Universitaet Dresden, 01062 Dresden (Germany)

    2010-10-15

    Ternary samarium-filled platinum-germanium skutterudite SmPt{sub 4}Ge{sub 12} was prepared at a pressure of 5.0(0.5) GPa and a temperature of 1070(70) K. The compound crystallizes in the cubic space group Im 3-bar (a=8.6069(4) A) and is isotypic with LaFe{sub 4}P{sub 12}. X-ray absorption spectroscopy measurements show that samarium in SmPt{sub 4}Ge{sub 12} has a temperature-independent intermediate valence ({nu}=2.90{+-}0.03). Magnetization data reveal Van Vleck paramagnetism above {approx}50 K. The low-temperature specific heat displays a broad anomaly centred at 2.9 K and a large linear coefficient {gamma} ' =450 mJ mol{sup -1} K{sup -2} suggesting heavy-fermion behaviour. Low-temperature electrical resistivity shows a temperature dependence reminiscent of the Kondo effect. Density functional calculations result in an electronic structure that is, apart from the Sm 4f contributions, very similar to LaPt{sub 4}Ge{sub 12}.

  8. Ni-Zn-Sm nanopowder ferrites: Morphological aspects and magnetic properties

    Science.gov (United States)

    Costa, A. C. F. M.; Diniz, A. P. A.; de Melo, A. G. B.; Kiminami, R. H. G. A.; Cornejo, D. R.; Costa, A. A.; Gama, L.

    Ni-Zn ferrites have been widely used in components for high-frequency range applications due to their high electrical resistivity, mechanical strength and chemical stability. Ni-Zn ferrite nanopowders doped with samarium with a nominal composition of Ni 0.5Zn 0.5Fe 2-xSm xO 4 ( x=0.0, 0.05, and 0.1 mol) were obtained by combustion synthesis using nitrates and urea as fuel. The morphological aspects of Ni-Zn-Sm ferrite nanopowders were investigated by X-ray diffraction, nitrogen adsorption by BET, sedimentation, scanning electron microscopy and magnetic properties. The results indicated that the Ni-Zn-Sm ferrite nanopowders were composed of soft agglomerates of nanoparticles with a high surface area (55.8-64.8 m 2/g), smaller particles (18-20 nm) and nanocrystallite size particles. The addition of samarium resulted in a reduction of all the magnetic parameters evaluated, namely saturation magnetization (24-40 emu/g), remanent magnetization (2.2-3.5 emu/g) and coercive force (99.3-83.3 Oe).

  9. Magnetic and magnetoelastic properties of epitaxial SmFe{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Fuente, C de la; Arnaudas, J I; Ciria, M; Del Moral, A [Departamento de Magnetismo de Solidos and Departamento de Fisica de la Materia Condensada, Instituto de Ciencia de los Materiales de Aragon and Universidad de Zaragoza, 50071, Zaragoza (Spain); Dufour, C; Dumesnil, K, E-mail: cesar@unizar.e [Laboratoire de Metallurgie Physique et de Science des Materiaux, Universite Henry Poincare, Nancy 1, BP 239, 54506 (France)

    2010-02-03

    We report on magnetic and magnetoelastic measurements for a 5000 A (110) SmFe{sub 2} thin film, which was successfully analyzed by means of a point charge model for describing the effect of the epitaxial growth in this kind of system. Some of the main conclusions of the Moessbauer and magnetoelastic results and the new magnetization results up to 5 T allow us to get a full description of the crystal electric field, exchange, and magnetoelastic behavior in this compound. So, new single-ion parameters are obtained for the crystal field interaction of samarium ions, A{sub 4}(r{sup 4}) = +755 K/ion and A{sub 6}(r{sup 6}) = -180 K/ion, and new single-ion magnetoelastic coupling B{sup gamma}{sup ,2}approx =-200 MPa and B{sup epsilon}{sup ,2}approx =800 MPa, which represent the tetragonal and the in-plane shear deformations, respectively. Moreover, the new thermal behavior of the samarium magnetic moment, the exchange coupling parameter, and the magnetocrystalline anisotropy of the iron sublattice are obtained too. From these, the softening of the spin reorientation transition with respect to the bulk case could be accounted for.

  10. Synergistic Effects of Sm and C Co-Doped Mixed Phase Crystalline TiO2 for Visible Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Fuchang Peng

    2017-02-01

    Full Text Available Mixed phase TiO2 nanoparticles with element doping by Sm and C were prepared via a facile sol-gel procedure. The UV-Vis light-diffuse reflectance spectroscopy analysis showed that the absorption region of co-doped TiO2 was shifted to the visible-light region, which was attributed to incorporation of samarium and carbon into the TiO2 lattice during high-temperature reaction. Samarium effectively decreased the anatase-rutile phase transformation. The grain size can be controlled by Sm doping to achieve a large specific surface area useful for the enhancement of photocatalytic activity. The photocatalytic activities under visible light irradiation were evaluated by photocatalytic degradation of methylene blue (MB. The degradation rate of MB over the Sm-C co-doped TiO2 sample was the best. Additionally, first-order apparent rate constants increased by about 4.3 times compared to that of commercial Degusssa P25 under the same experimental conditions. Using different types of scavengers, the results indicated that the electrons, holes, and •OH radicals are the main active species for the MB degradation. The high visible-light photocatalytic activity was attributed to low recombination of the photo-generated electrons and holes which originated from the synergistic effect of the co-doped ions and the heterostructure.

  11. Viability of biocompatible and biodegradable seeds production with incorporated radionuclides; Viabilidade da producao de sementes biocompativeis e biodegradaveis com radionuclideos incorporados

    Energy Technology Data Exchange (ETDEWEB)

    Roberto, W.S. [Centro Federal de Educacao Tecnologica de Ouro Preto (CEFET/OP), MG (Brazil); Pereira, M.M.; Vasconcelos, W.L.; Campos, T.P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)], e-mail: wanderley@nuclear.ufmg.br

    2000-07-01

    The present work aims the development of radioactive seeds, biocompatible and biodegradable, with the objective of adding options in the cancer treatment. The work focus on the production of seeds biodegradable that incorporate radioisotopes with half life inferior than the degradation time of the material. The idea of producing devices with biodegradable materials impregnated with radioisotopes of short half life will offer new possibilities in the cancer treatment, since they can be used following the same procedures of the permanent interstitial brachytherapy, but using degradable materials compatible with the physiological environment. It will be discussed in particular the possible application of these seeds in the treatment of prostate cancer. A review of the subject and a preliminary evaluation of the viability of production of the seeds will be presented. The method of production of the seeds is based on the incorporation of Iodine and Samarium in glass matrixes obtained by sol-gel processing. X-ray fluorescence was done in the samples produced and the incorporation of Iodine and Samarium atoms was confirmed. (author)

  12. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    Science.gov (United States)

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  13. Uptake and effect of rare earth elements on gene expression in Methylosinus trichosporium OB3b.

    Science.gov (United States)

    Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A; Semrau, Jeremy D

    2016-07-01

    It is well known that Methylosinus trichosporium OB3b has two forms of methane monooxygenase (MMO) responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase and a membrane-associated (particulate) methane monooxygenase, and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-type MeDH (Mxa-MeDH) and Xox-type MeDH (Xox-MeDH), and the expression of these two forms is regulated by the availability of the rare earth element (REE), cerium. Here, we extend these studies and show that lanthanum, praseodymium, neodymium and samarium also regulate expression of alternative forms of MeDH. The effect of these REEs on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b, where the Mxa-MeDH was knocked out, was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. Collectively, these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b, but that copper overrides the effect of other metals by an as yet unknown mechanism. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Threshold sensitivity of quartz variometers with negative feedback

    Science.gov (United States)

    Odintsov, V. I.; Petrov, V. G.

    2017-05-01

    The maximum achievable parameters of magnetometers based on optomechanical quartz variometers are studied in connection with the planned transition of the international network Intermagnet to 1-s recording and the need to provide the network of Russian geomagnetic observatories with domestic magnetometers that satisfy Intermagnet requirements. The mechanism of negative feedback effect on the sensitivity threshold of a variometer with an optoelectronic angle transducer is shown. The optimization criterion for the size and shape of the magnets made of different magnetic materials is defined by the maximum ratio of the magnetic moment to the inertial moment. Theoretical and experimental evaluation of the variometer noise level is based on vicalloy and samarium-cobalt. It is shown that the frequency range of magnetometers with variometers based on vicalloy and samarium-cobalt will be bounded from above by frequencies of 1.6 and 6.4 Hz, respectively, at a threshold sensitivity of about 1 pT. These ratios of the frequency and threshold sensitivity for the given magnetic materials are probably limited for quartz variometers with an optoelectronic angle transducer.

  15. Measurement of solubility of plutonium trifluoride and rare-earth fluorides in molten LiF-BeF{sub 2}-ZrF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Naumov, V.S.; Bychkov, A.V.; Kormilitsyn, M.V. [and others

    1996-12-01

    Data on behavior of plutonium fluoride and fission products (FP) dissolved in fuel composition are needed to calculate the duration of an operating cycle of the ADTT facility (Accelerator-Driver Transmutation Technologies) and to determine the effect of their equilibrium concentrations on nuclear-physical characteristics of reactor operation. The data on the FP fluoride solubility in the molten salts are of great important for some industrial processes (electrolytical metal deposition, development of physical-chemical mean for processes of chemical technology, etc.) As noted above, some information on this question is given in monography and articles. Data concerning fluoride salts are given in reports. However, it was impossible to make the substantial analysis of mutual solubility of fluoride melts. The primary investigation of CeF{sub 3} and neodymium, samarium and lanthanum fluorides showed that the solubility of the melt LiF-BeF{sub 2} and LiF-BeF{sub 2}-ThF{sub 4} was a linear function of reverse temperature and increases from lanthanum to samarium in the row of rare-earth elements. Disagreement in estimation of plutonium trifluoride solubility and incomplete data on the solubility of rare-earth elements prompted this study.

  16. Determination of the Speciation and Bioavailability of Sm to Chlamydomonas reinhardtii in the Presence of Natural Organic Matter.

    Science.gov (United States)

    Rowell, Justine-Anne; Fillion, Marc-Alexandre; Smith, Scott; Wilkinson, Kevin J

    2018-02-03

    As technological interest and environmental emissions of the rare earth elements (REE) increase, it is becoming more important to assess their potential environmental impact. Samarium (Sm) is a lanthanide of intermediate molar mass that is used in numerous high technology applications including wind turbines, solar panels and electric vehicles. The present study relates the speciation of samarium (Sm) determined in the presence of natural organic matter (NOM) to its bioavailability to the unicellular green alga, Chlamydomonas reinhardtii. The free ion concentration was determined using a cation exchange resin (IET) in dynamic mode and compared to thermodynamic modelling. Short-term biouptake experiments were performed in the presence of 4 types of NOM: Suwannee River fulvic acids, Pahokee Peat fulvic acids, Suwannee River humic acids and a Luther Marsh dissolved organic matter isolate (90-95% humic acids). The results clearly showed that even a small amount of NOM (0.5 mg C L-1 ) resulted in a significant decrease (10x) in the Sm internalization fluxes. Furthermore, complexation with humic acids (and the corresponding reduction in Sm bioavailability) was stronger than for the fulvic acids. The results showed that the experimentally measured (free) Sm was a better predictor of Sm internalization than either the total concentrations or the free ion concentrations obtained using thermodynamic modelling. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  17. Improved transistor-controlled and commutated brushless DC motors for electric vehicle propulsion

    Science.gov (United States)

    Demerdash, N. A.; Miller, R. H.; Nehl, T. W.; Nyamusa, T. A.

    1983-01-01

    The development, design, construction, and testing processes of two electronically (transistor) controlled and commutated permanent magnet brushless dc machine systems, for propulsion of electric vehicles are detailed. One machine system was designed and constructed using samarium cobalt for permanent magnets, which supply the rotor (field) excitation. Meanwhile, the other machine system was designed and constructed with strontium ferrite permanent magnets as the source of rotor (field) excitation. These machine systems were designed for continuous rated power output of 15 hp (11.2 kw), and a peak one minute rated power output of 35 hp (26.1 kw). Both power ratings are for a rated voltage of 115 volts dc, assuming a voltage drop in the source (battery) of about 5 volts. That is, an internal source voltage of 120 volts dc. Machine-power conditioner system computer-aided simulations were used extensively in the design process. These simulations relied heavily on the magnetic field analysis in these machines using the method of finite elements, as well as methods of modeling of the machine power conditioner system dynamic interaction. These simulation processes are detailed. Testing revealed that typical machine system efficiencies at 15 hp (11.2 kw) were about 88% and 84% for the samarium cobalt and strontium ferrite based machine systems, respectively. Both systems met the peak one minute rating of 35 hp.

  18. Study of rare earth separation by counter current electromigration; Estudo da separacao de terras raras por eletromigracao em contra corrente

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Sergio Machado

    1995-08-01

    The counter current electromigration (CCEM) is an electrophoretic technique where the charged species migrate on an electrical field toward an electrolytic flux. Usually this electrolyte is a complexing agent and is necessary to increase the small differences between the species mobilities. A new column was developed, all made of acrylic, in a cylindrical shape. A set of experiments was carried out with the species Na{sup +}/K{sup +}, K{sup +}/Sm{sup +3}, K{sup +}/Eu{sup +3} and K{sup +}/Sm{sup +3}/Eu{sup +3} using the {alpha}-hydrox i-isobutyric acid o,01 M as the counter current electrolytic flux. From a synthetic mixture of 90% of samarium and 10% of europium was obtained the samarium ion in a purity better than 99,9% where the concentration of Eu was determined by the polarography technique. The potassium ion was used as a leading electrolyte. It was also measured the mobilities of the involved species in the {alpha}-HIBA medium. Two models are proposed, a stationary model and a dynamic one. A simulator of a simplified stationary model, prepared in FORTRAN language, was developed and tested toward experimental results. (author)

  19. OXIDATIVE DEHYDROGENATION OF PROPANE BY RARE EARTH PHOSPHATES SUPPORTED ON AL-PILC

    Directory of Open Access Journals (Sweden)

    Carolina De Los Santos

    2012-12-01

    Full Text Available Catalytic activity in propane oxidative dehydrogenation of rare earth phosphates LnPO4 (where Ln = La, Ce, Pr, Nd, Sm and of the same supported by an aluminum pillared clay, of high specific surface area, is presented. The solids were characterized by TGA, XRD, nitrogen adsorption and immediate analysis after reaction in order to determine eventual carbon formation. Catalytic assays were performed at temperatures in the range 400oC-600oC, the reaction mixture was C3H8/O2/Ar = 10/10/80. All the catalysts were active. The reaction products were H2, CO, CO2, CH4, C2H4 and C3H6 and there were no organic oxygenated compounds detected. Although all the investigated systems were active, the Al-PILC supported catalysts presented a higher activity than the bulk materials. In this context, the samarium supported catalyst showed a propene yield increase from 4% to 10% compared with bulk samarium phosphate at 600°C. This effect was attributed to the increase in the specific surface area.

  20. Dry etching for microelectronics

    CERN Document Server

    Powell, RA

    1984-01-01

    This volume collects together for the first time a series of in-depth, critical reviews of important topics in dry etching, such as dry processing of III-V compound semiconductors, dry etching of refractory metal silicides and dry etching aluminium and aluminium alloys. This topical format provides the reader with more specialised information and references than found in a general review article. In addition, it presents a broad perspective which would otherwise have to be gained by reading a large number of individual research papers. An additional important and unique feature of this book