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Sample records for hafnium 176

  1. Evolution of E 2 transition strength in deformed hafnium isotopes from new measurements on 172Hf,174Hf, and 176Hf

    Science.gov (United States)

    Rudigier, M.; Nomura, K.; Dannhoff, M.; Gerst, R.-B.; Jolie, J.; Saed-Samii, N.; Stegemann, S.; Régis, J.-M.; Robledo, L. M.; Rodríguez-Guzmán, R.; Blazhev, A.; Fransen, Ch.; Warr, N.; Zell, K. O.

    2015-04-01

    Background: The available data for E 2 transition strengths in the region between neutron-deficient hafnium and platinum isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, particularly in heavy-mass regions, which should be highly complex, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf as a representative case. Purpose: We remeasure the 21+ half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. Method: The half-lives were measured using γ -γ and conversion-electron-γ delayed coincidences with the fast timing method. For the determination of half-lives in the picosecond region, the generalized centroid difference method was applied. For the theoretical calculation of the spectroscopic properties, the interacting boson model is employed, whose Hamiltonian is determined based on microscopic energy-density functional calculations. Results: The measured 21+ half-lives disagree with results from earlier γ -γ fast timing measurements, but are in agreement with data from Coulomb excitation experiments and other methods. Half-lives of the 41+ and 61+ states were measured, as well as a lower limit for the 81+ states. Conclusions: This work shows the importance of a mass-dependent effective boson charge in the interacting boson model for the description of E 2 transition rates in chains of nuclei. It encourages further studies of the microscopic origin of this mass dependence. New experimental

  2. Metallurgy of zirconium and hafnium

    International Nuclear Information System (INIS)

    Baryshnikov, N.V.; Geger, V.Eh.; Denisova, N.D.; Kazajn, A.A.; Kozhemyakin, V.A.; Nekhamkin, L.G.; Rodyakin, V.V.; Tsylov, Yu.A.

    1979-01-01

    Considered are those properties of zirconium and of hafnium, which are of practical interest for the manufacture of these elements. Systematized are the theoretical and the practical data on the procedures for thermal decomposition of zirconia and for obtaining zirconium dioxide and hafnium dioxide by a thermal decomposition of compounds and on the hydrometallurgical methods for extracting zirconium and hafnium. Zirconium and hafnium fluorides and chlorides production procedures are described. Considered are the iodide and the electrolytic methods of refining zirconium and hafnium

  3. SEPARATING HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Lister, B.A.J.; Duncan, J.F.

    1956-08-21

    A dilute aqueous solution of zirconyl chloride which is 1N to 2N in HCl is passed through a column of a cation exchange resin in acid form thereby absorbing both zirconium and associated hafnium impurity in the mesin. The cation exchange material with the absorbate is then eluted with aqueous sulfuric acid of a O.8N to 1.2N strength. The first portion of the eluate contains the zirconium substantially free of hafnium.

  4. Commercial production of metal hafnium and hafnium-based products

    International Nuclear Information System (INIS)

    Negodin, D.A.; Shtutsa, M.G.; Akhtonov, S.G.; Il'enko, E.V.; Kobyzev, A.M.

    2012-01-01

    Hafnium possesses a unique complex of physical and chemical properties which allow the application of products on its basis in various industries. Joint Stock Company 'Chepetsky Mechanical Plant' is the single enterprise which produces hafnium on the territory of Russia. The manufacture of metal hafnium with the total content of zirconium and hafnium, at least, 99,8 % of weights is developed at the present time at Joint Stock Company CHMZ. The weight of melted hafnium ingots is up to 1 ton. Manufacture of wide range of products from hafnium is implemented. The plates from a hafnium with thickness of 0.60 mm which are used for emergency control cartridges of VVER-440 reactors are the most critical product. It is shown that ingots and products obtained from metal hafnium correspond to the Russian and international standards for reactor materials in chemical composition, mechanical and corrosion properties.

  5. Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

    International Nuclear Information System (INIS)

    MJ Trbovich; DP Barry; RE Slovacck; Y Danon; RC Block; JA Burke; NJ Drindak; G Leinweber; RV Ballad

    2004-01-01

    The focus of this work is to determine resonance parameters for stable hafnium isotopes in the 0.005-200 eV region, with special emphasis on the overlapping 176 Hf and 178 Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it a useful material for controlling nuclear reactions. Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) using the time of flight method. 6 Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen section NaI(Tl) multiplicity detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotopically-enriched liquid samples. The liquid samples were designed to provide information on the 176 Hf and 178 Hf contributions to the 8 eV doublet without saturation. Data analysis was done using the R-matrix Bayesian code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for multiple scattering effects in neutron capture yield data. The combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005-200 eV. Resonance integrals were calculated along with errors for each hafnium isotope using the NJOY [1] and INTER [2] codes. The isotopic resonance integrals calculated were significantly different than previously published values; however the calculated elemental hafnium resonance integral changed very little

  6. Zirconium and hafnium

    Science.gov (United States)

    Jones, James V.; Piatak, Nadine M.; Bedinger, George M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Zirconium and hafnium are corrosion-resistant metals that are widely used in the chemical and nuclear industries. Most zirconium is consumed in the form of the main ore mineral zircon (ZrSiO4, or as zirconium oxide or other zirconium chemicals. Zirconium and hafnium are both refractory lithophile elements that have nearly identical charge, ionic radii, and ionic potentials. As a result, their geochemical behavior is generally similar. Both elements are classified as incompatible because they have physical and crystallochemical properties that exclude them from the crystal lattices of most rock-forming minerals. Zircon and another, less common, ore mineral, baddeleyite (ZrO2), form primarily as accessory minerals in igneous rocks. The presence and abundance of these ore minerals in igneous rocks are largely controlled by the element concentrations in the magma source and by the processes of melt generation and evolution. The world’s largest primary deposits of zirconium and hafnium are associated with alkaline igneous rocks, and, in one locality on the Kola Peninsula of Murmanskaya Oblast, Russia, baddeleyite is recovered as a byproduct of apatite and magnetite mining. Otherwise, there are few primary igneous deposits of zirconium- and hafnium-bearing minerals with economic value at present. The main ore deposits worldwide are heavy-mineral sands produced by the weathering and erosion of preexisting rocks and the concentration of zircon and other economically important heavy minerals, such as ilmenite and rutile (for titanium), chromite (for chromium), and monazite (for rare-earth elements) in sedimentary systems, particularly in coastal environments. In coastal deposits, heavy-mineral enrichment occurs where sediment is repeatedly reworked by wind, waves, currents, and tidal processes. The resulting heavy-mineral-sand deposits, called placers or paleoplacers, preferentially form at relatively low latitudes on passive continental margins and supply 100 percent of

  7. SEPARATION OF HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Overholser, L.B.; Barton, C.J. Sr.; Ramsey, J.W.

    1960-05-31

    The separation of hafnium impurities from zirconium can be accomplished by means of organic solvent extraction. The hafnium-containing zirconium feed material is dissolved in an aqueous chloride solution and the resulting solution is contacted with an organic hexone phase, with at least one of the phases containing thiocyanate. The hafnium is extracted into the organic phase while zirconium remains in the aqueous phase. Further recovery of zirconium is effected by stripping the onganic phase with a hydrochloric acid solution and commingling the resulting strip solution with the aqueous feed solution. Hexone is recovered and recycled by means of scrubbing the onganic phase with a sulfuric acid solution to remove the hafnium, and thiocyanate is recovered and recycled by means of neutralizing the effluent streams to obtain ammonium thiocyanate.

  8. Calorimetric measurements on hafnium titanate

    International Nuclear Information System (INIS)

    Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.

    2012-01-01

    Owing to its desirable nuclear and mechanical properties such as good absorption cross-section for thermal neutrons (105 barns), hafnium titanate (HfTiO 4 ) finds application as control rods for nuclear reactors. An accurate knowledge of the thermo physical properties of this material is necessary for design of control rod and for modeling its performance. Heat capacity is an important thermodynamic property that determines the temperature dependent variation of all other thermodynamic properties. Hence enthalpy increments of hafnium titanate (HfTiO 4 ) were measured in the temperature range 803-1663 K by employing the method of inverse drop calorimetry using high temperature differential calorimeter

  9. Hafnium carbide formation in oxygen deficient hafnium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rodenbücher, C. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); Hildebrandt, E.; Sharath, S. U.; Kurian, J.; Komissinskiy, P.; Alff, L. [Technische Universität Darmstadt, Institute of Materials Science, 64287 Darmstadt (Germany); Szot, K. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); University of Silesia, A. Chełkowski Institute of Physics, 40-007 Katowice (Poland); Breuer, U. [Forschungszentrum Jülich GmbH, Central Institute for Engineering, Electronics and Analytics (ZEA-3), 52425 Jülich (Germany); Waser, R. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); RWTH Aachen, Institute of Electronic Materials (IWE 2), 52056 Aachen (Germany)

    2016-06-20

    On highly oxygen deficient thin films of hafnium oxide (hafnia, HfO{sub 2−x}) contaminated with adsorbates of carbon oxides, the formation of hafnium carbide (HfC{sub x}) at the surface during vacuum annealing at temperatures as low as 600 °C is reported. Using X-ray photoelectron spectroscopy the evolution of the HfC{sub x} surface layer related to a transformation from insulating into metallic state is monitored in situ. In contrast, for fully stoichiometric HfO{sub 2} thin films prepared and measured under identical conditions, the formation of HfC{sub x} was not detectable suggesting that the enhanced adsorption of carbon oxides on oxygen deficient films provides a carbon source for the carbide formation. This shows that a high concentration of oxygen vacancies in carbon contaminated hafnia lowers considerably the formation energy of hafnium carbide. Thus, the presence of a sufficient amount of residual carbon in resistive random access memory devices might lead to a similar carbide formation within the conducting filaments due to Joule heating.

  10. Hafnium isotope stratigraphy of ferromanganese crusts

    Science.gov (United States)

    Lee; Halliday; Hein; Burton; Christensen; Gunther

    1999-08-13

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in (87)Sr/(86)Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  11. Ferroelectricity in undoped hafnium oxide

    International Nuclear Information System (INIS)

    Polakowski, Patrick; Müller, Johannes

    2015-01-01

    We report the observation of ferroelectric characteristics in undoped hafnium oxide thin films in a thickness range of 4–20 nm. The undoped films were fabricated using atomic layer deposition (ALD) and embedded into titanium nitride based metal-insulator-metal (MIM) capacitors for electrical evaluation. Structural as well as electrical evidence for the appearance of a ferroelectric phase in pure hafnium oxide was collected with respect to film thickness and thermal budget applied during titanium nitride electrode formation. Using grazing incidence X-Ray diffraction (GIXRD) analysis, we observed an enhanced suppression of the monoclinic phase fraction in favor of an orthorhombic, potentially, ferroelectric phase with decreasing thickness/grain size and for a titanium nitride electrode formation below crystallization temperature. The electrical presence of ferroelectricity was confirmed using polarization measurements. A remanent polarization P r of up to 10 μC cm −2 as well as a read/write endurance of 1.6 × 10 5 cycles was measured for the pure oxide. The experimental results reported here strongly support the intrinsic nature of the ferroelectric phase in hafnium oxide and expand its applicability beyond the doped systems

  12. Systematic investigation of electromagnetic properties of all stable hafnium isotopes

    International Nuclear Information System (INIS)

    Napiorkowski, T.J.; Choinski, J.; Czosnyka, T.; Iwanicki, J.; Kownacki, J.; Zemlo, L.; Srebrny, J.; Starosta, K.; Boer, J. de.; Gollwitzer, A.; Loewe, M.; Wuerkner, M.; Guenther, C.; Weber, T.; Hagemann, G.; Sletten, G.

    1996-01-01

    In a systematic investigation of the electromagnetic structure of hafnium stable isotopes enriched targets of 176, 177, 178, 179, 180 Hf were Coulomb exciting using: 67 MeV 19 F beam from NBITAL FN Tandem, 125 MeV 32 S beam from MP Tandem in Accelerator Laboratory LMU and TU Munich, 225 MeV 58 Ni beam from NBITAL FN Tandem plus 2 Liniac Boosters complex. Scattered particle-gamma as well as p-γ-γ coincidence were registered. A further simultaneous analysis of Coulomb excitation cross section as a function of scattering angle of 19 F, 32 S, 58 Ni projectiles should be sufficient to deduce reduced probabilities of E2 transitions in ground state band

  13. Study of fine structure of deformed hafnium

    International Nuclear Information System (INIS)

    Voskresenskaya, L.A.; Petukhova, A.S.; Kovalev, K.S.

    1978-01-01

    Variations in the hafnium fine structure following the cold plastic deformation have been studied. The fine structure condition has been studied through the harmonic analysis of the profile of the X-ray diffraction line, obtained at the DRON-I installation. Received has been the dependence of the crystal lattice microdistortions value on the deformation extent for hafnium. This dependence is compared with the corresponding one for zirconium. It is found out that at all the deformations the microdistortion distribution is uniform. The microdistortion value grows with the increase in the compression. During the mechanical impact higher microdistortions of the crystal lattice occur in the hafnium rather than in zirconium

  14. Hafnium - material for chemical apparatus engineering

    International Nuclear Information System (INIS)

    Jennert, D.

    1981-01-01

    This work describes - on the background of available literature - the properties of hafnium in technical quality (DIN-material No. 2.6400) as material for chemical apparatus engineering. The occurence, refining, physical and chemical properties will be described as well as the material behavior. In conclusion, it has been found that there is, at present, sufficient information for the engineering of hafnium which has to be completed by additional investigations for special applications. (orig.) [de

  15. Determination of hafnium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Yoshida, Isao; Kobayashi, Hiroshi; Ueno, Keihei.

    1977-01-01

    Optimum conditions for atomic absorption spectrophotometric determination of hafnium were investigated by use of a Jarrel-Ash AA-1 instrument which was equipped with a premixed gas burner slotted 50 mm in length and 0.4 mm in width. Absorption of hafnium, which was atomized in an nitrous oxide-acetylene flame, was measured on a resonance line at 307.29 nm. The absorption due to hafnium was enhanced in the presence of ammonium fluoride and iron(III) ion, as shown in Figs. 2 and 3, depending on their concentration. The highest absorption was attained by the addition of (0.15 -- 0.3)M ammonium fluoride, 0.07 M of iron(III) ion and 0.05 M of hydrochloric acid. An excess of the additives decreased the absorption. The presence of zirconium, which caused a significant interference in the ordinary analytical methods, did not affect the absorption due to hafnium, if the zirconium concentration is less than 0.2 M. A standard procedure was proposed; A sample containing a few mg of hafnium was dissolved in a 25-ml volumetric flask, and ammonium fluoride, ferric nitrate and hydrochloric acid were added so that the final concentrations were 0.3, 0.07 and 0.05 M, respectively. Atomic absorption was measured on the aqueous solution in a nitrous oxide-acetylene flame and the hafnium content was calculated from the absorbance. Sensitivity was as high as 12.5 μg of Hf/ml/l% absorption. The present method is especially recommendable to the direct determination of hafnium in samples containing zirconium. (auth.)

  16. Titanium(IV), zirconium, hafnium and thorium

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    Titanium can exist in solution in a number of oxidation states. The titanium(IV) exists in acidic solutions as the oxo-cation, TiO 2+ , rather than Ti 4+ . Zirconium is used in the ceramics industry and in nuclear industry as a cladding material in reactors where its reactivity towards hydrolysis reactions and precipitation of oxides may result in degradation of the cladding. In nature, hafnium is found together with zirconium and as a consequence of the contraction in ionic radii that occurs due to the 4f -electron shell, the ionic radius of hafnium is almost identical to that of zirconium. All isotopes of thorium are radioactive and, as a consequence of it being fertile, thorium is important in the nuclear fuel cycle. The polymeric hydrolysis species that have been reported for thorium are somewhat different to those identified for zirconium and hafnium, although thorium does form the Th 4 (OH) 8 8+ species.

  17. Gravimetric determination of hafnium through its arsenate in carbide and boride of hafnium

    International Nuclear Information System (INIS)

    Rasulbekova, R.A.; Mamedov, I.A.

    1976-01-01

    A gravimetric method of determining hafnium through hydroarsenate has been recommended. The method differs from the known ones by its simplicity and by the recalculation coefficient which is more than by 50% smaller than that used in preparing a weight form of HfO 2 . Upon development of gravimetric determination of hafnium through hydro-and pyroarsenate, an investigation has been conducted with the aim to find some physico-chemical constants of hafnium hydroarsenate. The weighed amount of hafnium hydroarsenate is dissolved in sulphuric acid (2:5). The precipitate of hafnium hydroarsenate has been studied for recording infrared absorption spectra. Thermographic analysis of the precipitate has been performed. Thermogram reveals endothermal effect at 105 deg C and exothermal at 840 deg C. Water solubility of hafnium has been determined equal to 1.75x10 6 g mol/l. The corresponding solubility product of the precipitate has been calculated which is 2.1x10 -17 . It is shown that the method possesses certain selectivity, sufficient accuracy, and is rather fast. It has been established that determination can be performed in the presence of excess amounts of ions

  18. Method of separating hafnium from zirconium

    International Nuclear Information System (INIS)

    Megy, J.A.

    1980-01-01

    English. A new anhydrous method was developed for separating zirconium and hafnium, which gives higher separation factors and is more economical than previous methods. A molten phase, comprising a solution of unseparated zirconium and hafnium and a solvent metal, is first prepared. The molten metal phase is contacted with a fused salt phase which includes a zirconium salt. Zirconium and hafnium separation is effected by mutual displacement with hafnium being transported from the molten metal phase to the fused salt phase, while zirconium is transported from the fused salt phase to the molten metal phase. The solvent metal is less electropositive than zirconium. Zinc was chosen as the solvent metal, from a group which also included cadmium, lead, bismuth, copper, and tin. The fused salt phase cations are more electropositive than zirconium and were selected from a group comprising the alkali elements, the alkaline earth elements, the rare earth elements, and aluminum. A portion of the zirconium in the molten metal phase was oxidized by injecting an oxidizing agent, chlorine, to form zirconium tetrachlorid

  19. Kinetic studies on the hafnium nad deuterium

    International Nuclear Information System (INIS)

    Bing Wenzeng; Long Xinggui; Zhu Zuliang

    2009-04-01

    Through the method of reaction rate analysis in a constant volume reactor, the time dependence of the pressure drop of the hafnium deuteride formation are studied over a temperature range 573-873 K on a metal hydride thermodynamic and kinetic parameters measuring apparatus. The rate constants of the hafnium deuteride formation, which are 0.0530 s -1 , 0.0452 s -1 , 0.0319 s -1 , 0.0261 s -1 , are calculated at a serial temperatures of 573 K, 673 K, 773 K, 873 K and the initial pressure of 13 kPa. The activation energy of the reaction is (-10.1±1.5) kJ·mol -1 . Comparing the above results with those of titanium deuteride formation on the same measuring apparatus, the kinetic mechanism of the deuteride formation of hafnium and titanium is considered different. It is concluded that the reaction rate of hafnium absorbing deuterium may be controlled by phase transformation and surface oxidation. (authors)

  20. Recovery of hafnium values from loaded extraction solvent

    International Nuclear Information System (INIS)

    Abodishish, H.A.

    1989-01-01

    This patent describes an improvement in a process for recovering high purity hafnium hydroxide from a methyl isobutyl ketone organic solvent that is substantially free of sulfate ions and contains hafnium thiocyanate and thiocyanic acid. The improvement comprising reacting the organic solvent with ammonia to produce a reaction product in the form of a methyl isobutyl ketone organic solvent that is substantially free of sulfate ions and contains ammonium thiocyanite solution and hafnium hydroxide; separating the constituents of the reaction product in accordance with their respective specific gravities to produce a hafnium hydroxide sludge as one of the separation products; and removing the liquid component of the sludge to yield a high purity hafnium hydroxide ready for calcination to hafnium oxide

  1. Flotation separation of hafnium(IV) from aqueous solutions

    International Nuclear Information System (INIS)

    Downey, D.M.; Narick, C.N.; Cohen, T.A.

    1985-01-01

    A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175+181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author)

  2. Flotation separation of hafnium(IV) from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Downey, D.M.; Narick, C.N.; Cohen, T.A.

    1985-09-01

    A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175 + 181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author). 21 refs.; 5 figs.

  3. Titanium zirconium and hafnium coordination compounds with vanillin thiosemicarbazone

    International Nuclear Information System (INIS)

    Konunova, Ts.B.; Kudritskaya, S.A.

    1987-01-01

    Coordination compounds of titanium zirconium and hafnium tetrachlorides with vanillin thiosemicarbazone of MCl 4 x nLig composition, where n=1.5, 4 for titanium and 1, 2, 4 for zirconium and hafnium, are synthesized. Molar conductivity of ethanol solutions is measured; IR spectroscopic and thermochemical investigation are carried out. The supposition about ligand coordination via sulfur and azomethine nitrogen atoms is made. In all cases hafnium forms stable compounds than zirconium

  4. Niobium and hafnium grown on porous membranes

    International Nuclear Information System (INIS)

    Morant, C.; Marquez, F.; Campo, T.; Sanz, J.M.; Elizalde, E.

    2010-01-01

    In this work we report on a method for fabricating highly ordered nanostructures of niobium and hafnium metals by physical vapour deposition using two different templates: anodized aluminum oxide membranes (AAO) and zirconium onto AAO membranes (Zr/AAO). The growth mechanism of these metal nanostructures is clearly different depending on the material used as a template. A different morphology was obtained by using AAO or Zr/AAO templates: when the metal is deposited onto AAO membranes, nanospheres with ordered hexagonal regularity are obtained; however, when the metal is deposited onto a Zr/AAO template, highly ordered nanocones are formed. The experimental approach described in this work is simple and suitable for synthesizing nanospheres or nanoholes of niobium and hafnium metals in a highly ordered structure.

  5. Joint titrimetric determination of zirconium and hafnium

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Botbol, Moises; Bianco de Salas, G.N.; Cornell de Casas, M.I.

    1980-01-01

    A method for the joint titrimetric determination of zirconium and hafnium, which are elements of similar chemical behaviour, is described. The disodic salt of the ethylendiaminetetracetic acid (EDTA) is used for titration, while xilenol orange serves as final point indicator. Prior to titration it is important to evaporate with sulfuric acid, the solution resulting from the zirconium depolymerization process, to adjust the acidity and to eliminate any interferences. The method, that allows the quick and precise determination of zirconium and hafnium in quantities comprised between 0.01 and mg, was applied to the analysis of raw materials and of intermediate and final products in the fabrication of zirconium sponge and zircaloy. (M.E.L.) [es

  6. Molten salt scrubbing of zirconium or hafnium tetrachloride

    International Nuclear Information System (INIS)

    Lee, E.D.; McLaughlin, D.F.

    1990-01-01

    This patent describes a continuous process for removing impurities of iron or aluminum chloride or both from vaporous zirconium or hafnium chloride or both. It comprises: introducing impure zirconium or hafnium chloride vapor or both into a middle portion of an absorbing column containing a molten salt phase, the molten salt phase absorbing the impurities of iron or aluminum chloride or both to produce chloride vapor stripped of zirconium or hafnium chloride; introducing sodium or potassium chloride or both into a top portion of the column; controlling the top portion of the column to between 300--375 degrees C.; heating a bottom portion of the column to 450--550 degrees C. To vaporize zirconium chloride or hafnium chloride or hafnium and zirconium chloride from the molten salt; withdrawing molten salt substantially free of zirconium and hafnium chloride from the bottom portion of the column; and withdrawing zirconium chloride or hafnium chloride or hafnium and zirconium chloride vapor substantially free of impurities of iron and aluminum chloride from the top of the column

  7. Excess hafnium-176 in meteorites and the early Earth zircon record

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Connelly, James; Thrane, Kristine

    2012-01-01

    The long-lived Lu-to- Hf decay system is a powerful tool to understand ancient chemical fractionation events associated with planetary differentiation. Detrital Hadean zircons (>3.8 Gyr) from the Jack Hills metasedimentary belt of Western Australia record extremely enriched Hf-isotope signals sug...... crust prior to ~4.4 Gyr. This new view suggests continuous juvenile crustal growth and recycling throughout the Hadean and Archean eras, perhaps analogous to modern plate tectonics....

  8. Investigation of ferromagnetism in oxygen deficient hafnium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Krockenberger, Yoshiharu; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Suter, Andreas [PSI, Villingen (Switzerland); Wilhelm, Fabrice; Rogalev, Andrei [ESRF, Grenoble (France)

    2008-07-01

    Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by X-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films.

  9. Preparation of hafnium carbide by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hertz, Dominique.

    1974-01-01

    Hard, adhesive coatings of single-phase hafnium carbide were obtained by chemical vapor reaction in an atmosphere containing hafnium tetrachloride, methane and a large excess of hydrogen. By varying the gas phase composition and temperature the zones of formation of the different solid phases were studied and the growth of elementary hafnium and carbon deposits evaluated separately. The results show that the mechanism of hafnium carbide deposition does not hardly involve phenomene of homogeneous-phase methane decomposition or tetrachloride reduction by hydrogen unless the atmosphere is very rich or very poor in methane with respect to tetrachloride. However, hydrogen acting inversely on these two reactions, affects the stoichiometry of the substance deposited. The methane decomposition reaction is fairly slow, the reaction leading to hafnium carbide deposition is faster and that of tetrachloride reduction by hydrogen is quite fast [fr

  10. Assessing hafnium on hafnia as an oxygen getter

    International Nuclear Information System (INIS)

    O'Hara, Andrew; Demkov, Alexander A.; Bersuker, Gennadi

    2014-01-01

    Hafnium dioxide or hafnia is a wide band gap dielectric used in a range of electronic applications from field effect transistors to resistive memory. In many of these applications, it is important to maintain control over oxygen stoichiometry, which can be realized in practice by using a metal layer, specifically hafnium, to getter oxygen from the adjacent dielectric. In this paper, we employ density functional theory to study the thermodynamic stability of an interface between (100)-oriented monoclinic hafnia and hafnium metal. The nudged elastic band method is used to calculate the energy barrier for migration of oxygen from the oxide to the metal. Our investigation shows that the presence of hafnium lowers the formation energy of oxygen vacancies in hafnia, but more importantly the oxidation of hafnium through the migration of oxygen from hafnia is favored energetically

  11. Properties of filmogen solutions and films of hafnium compounds

    International Nuclear Information System (INIS)

    Sviridova, A.I.

    1986-01-01

    Study on hafnium hydrolizing compound solutions, used for hafnium oxide homogeneous layer formation, is conducted. In particular, electric conductivity, acidity and refractive index were investigated depending on the sal on ether concentration and the storage time. Oxyhafnium nitrate, hafnium chloride in ethanol, dichlorodiethoxyhafnium, hafnium oxychloride were used as initial compounds. Hydrolysis of hafnium compounds in solution occurs partially; further process occurs in the thin layer on the optical element surface; final decomposition is performed under heat treatment. It is ascertained, that alcoholic-aqueous solutions of inorganic salts can be filmogen only at definite acidity, density and viscosity (1.33-2.5 cp.). It is also ascertained that refractive index values and transmission spectral boundary of coatings, produced from alkoxy compound solutions and from chloride salt solutions, are practically the same. Transmittance boundary in ultraviolet region of spectrum of oxide films produced from nitrate and chloride solutions, varies with the heating temperature increase differently

  12. Analysis of hafnium in zirconium alloys

    International Nuclear Information System (INIS)

    Kondo, Isao; Sakai, Fumiaki; Ohuchi, Yoshifusa; Nakamura, Hisashi

    1977-01-01

    It is required to analyse alloying components and impurity elements in the acceptance analysis of zirconium alloys as the material for fuel cladding tubes and pressure tubes for advanced thermal reactors. Because of extreme similarity in chemical properties between zirconium and hafnium, about 100 ppm of hafnium is usually contained in zirconium alloys. Zircaloy-2 alloy and 2.5% Nb-zirconium with the addition of hafnium had been prepared as in-house standard samples for rapid analysis. Study was made on fluorescent X-ray analysis and emission spectral analysis to establish the analytical method. By using these in-house standard samples, acceptance analysis was successfully carried out for the fuel cladding tubes for advanced thermal reactors. Sulfuric acid solution was prepared from JAERI-Z 1, 2 and 3, the standard sample for zircaloy-2 prepared by the Analytical Committee on Nuclear Fuel and Reactor Materials, JAERI, and zirconium oxide (Hf 1 ppm/Zr). Standard Hf solution was added to the sulfuric acid solution step by step, to make up a series of the standard oxide samples by the precipitation process. By the use of these standard samples, the development of the analytical method and joint analysis were made by the three-member analytical technique research group including PNC. The analytical precision for the fluorescent X-ray analysis was improved by attaching a metallic yttrium filter to the window of an X-ray tube so as to suppress the effect due to zirconium matrix. The variation factor of the joint analysis was about 10% to show good agreement, and the indication value was determined. (Kobatake, H.)

  13. Primary hafnium metal sponge and other forms, approved standard 1973

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    A specification is presented covering virgin hafnium metal commonly designated as sponge because of its porous, sponge-like texture; it may also be in other forms such as chunklets. The specification does not cover crystal bar

  14. Investigation of colourless complexes of thorium, hafnium and zirconium

    International Nuclear Information System (INIS)

    Kiciak, S.; Stefanowicz, T.; Gontarz, H.; Swit, Z.

    1980-01-01

    The investigations conducted in the Institute of General Chemistry of Poznan Technical University in partial cooperation with Kharkhof Technical University related with thorium, hafnium and zirconium complexes are reviewed. (author)

  15. Molten salt extractive distillation process for zirconium-hafnium separation

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1989-01-01

    This patent describes an improvement in a process for zirconium-hafnium separation. It utilizes an extractive distillation column with a mixture of zirconium and hafnium tetrachlorides introduced into a distillation column having a top and bottom with hafnium enriched overheads taken from the top of the column and a molten salt solvent circulated through the column to provide a liquid phase, and with molten salt solvent containing zirconium chloride being taken from the bottom of the distillation column. The improvements comprising: utilizing a molten salt solvent consisting principally of lithium chloride and at least one of sodium, potassium, magnesium and calcium chlorides; stripping of the zirconium chloride taken from the bottom of the distillation column by electrochemically reducing zirconium from the molten salt solvent; and utilizing a pressurized reflux condenser on the top of the column to add the hafnium chloride enriched overheads to the molten salt solvent previously stripped of zirconium chloride

  16. Internal Dosimetry for Inhalation of Hafnium Tritide Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Inkret, W.C.T.; Schillaci, M.E.; Boyce, M.K.; Cheng, Y.S.; Efurd, D.W.; Little, T.T.; Miller, G.; Musgrave, J.A.; Wermer, J.R

    2001-07-01

    Metal tritides with low dissolution rates may have residence times in the lungs which are considerably longer than the biological half-time normally associated with tritium in body water, resulting in long-term irradiation of the lungs by low energy {beta} particles and bremsstrahlung X rays. Samples of hafnium tritide were placed in a lung simulant fluid to determine approximate lung dissolution rates. Hafnium hydride samples were analysed for particle size distribution with a scanning electron microscope. Lung simulant data indicated a biological dissolution half-time for hafnium tritide on the order of 10{sup 5}d. Hafnium hydride particle sizes ranged between 2 and 10 {mu}m, corresponding to activity median aerodynamic diameters of 5 to 25 {mu}m. Review of in vitro dissolution data, development of a biokinetic model, and determination of secondary limits for 1 {mu}m AMAD particles are presented and discussed. (author)

  17. New solvent extraction process for zirconium and hafnium

    International Nuclear Information System (INIS)

    Takahashi, M.; Katoh, Y.; Miyazaki, H.

    1984-01-01

    The authors' company developed a new solvent extraction process for zirconium and hafnium separation, and started production of zirconium sponge by this new process in September 1979. The process utilizes selective extraction of zirconium oxysulfate using high-molecular alkyl amine, and has the following advantages: 1. This extraction system has a separation factor as high as 10 to 20 for zirconium and hafnium in the range of suitable acid concentration. 2. In the scrubbing section, removal of all the hafnium that coexists with zirconium in the organic solvent can be effectively accomplished by using scrubbing solution containing hafnium-free zirconium sulfate. Consequently, hafnium in the zirconium sponge obtained is reduced to less than 50 ppm. 3. The extractant undergoes no chemical changes but is very stable for a long period. In particular, its solubility in water is small, about 20 ppm maximum, posing no environmental pollution problems such as are often caused by other process raffinates. At the present time, the zirconium and hafnium separation operation is very stable, and zirconium sponge made by this process can be applied satisfactorily to nuclear reactors

  18. Separation process of zirconium and hafnium

    International Nuclear Information System (INIS)

    Hure, J.; Saint-James, R.

    1955-01-01

    About the separation different processes of zirconium-hafnium, the extraction by solvent in cross-current is the most easily the process usable on an industrial scale. It uses tributyl phosphate as solvent, diluted with white spirit to facilitate the decanting. Some exploratory tests showed that nitric environment seemed the most favorable for extraction; but a lot of other factors intervene in the separation process. We studied the influence of the acidity successively, the NO 3 - ions concentration, the role of the cation coming with NO 3 - , as well as the influence of the concentration of zirconium in the solution on the separation coefficient β = α Zr / α Hf . (M.B.) [fr

  19. The interaction of fast neutrons with hafnium

    International Nuclear Information System (INIS)

    Smith, A.B.

    2002-01-01

    Elemental hafnium neutron total cross sections are measured from ∼0.75 to 4.5 MeV in steps of ∼40 keV. Differential neutron elastic-scattering cross sections are measured from ∼4.5 to 10.0 MeV in ∼0.5 MeV steps and at 40 scattering angles distributed between ∼17 and 160 deg. These data are combined with those found in the literature to construct a comprehensive experimental data base which is interpreted in terms of coupled-channels models. Physical characteristics of the resulting potentials are discussed. Comparisons are made with ENDF/B-6 (MAT 7200). A detailed report of this work is given by Smith (Smith, A., 2001. Argonne National Laboratory Report ANL/NDM-153)

  20. High temperature diffusion of hafnium in tungsten and a tungsten-hafnium carbide alloy

    International Nuclear Information System (INIS)

    Ozaki, Y.; Zee, R.H.

    1994-01-01

    Refractory metals and ceramics are used extensively in energy systems due to their high temperature properties. This is particularly important in direct conversion systems where thermal to electric conversion efficiency is a direct function of temperature. Tungsten, which has the highest melting temperature among elemental metals, does not possess sufficient creep resistance at temperature above 1,600 K. Different dispersion strengthened tungsten alloys have been developed to extend the usefulness of tungsten to higher temperatures. One of these alloys, tungsten with 0.4 mole percent of finely dispersed HfC particles (W-HfC), has the optimum properties for high temperature applications. Hafnium carbide is used as the strengthening agent due to its high chemical stability and its compatibility with tungsten. The presence of HfC particles retards the rate of grain growth as well as restricting dislocation motion. Both of which are beneficial for creep resistance. The long term behavior of this alloy depends largely on the evolution of its microstructure which is governed by the diffusion of its constituents. Data on the diffusion of carbon in tungsten and tungsten self-diffusion are available, but no direct measurements have been made on the diffusion of hafnium in tungsten. The only diffusion data available are estimated from a coarsening study and these data are highly unreliable. In this study, the diffusion behavior of hafnium in pure tungsten and in a W-HfC alloy was directly measured by means of Secondary Ion Mass Spectroscopy (SIMS). The selection of the W-HfC alloy is due to its importance in high temperature engineering applications, and its higher recrystallization temperature. The presence of HfC particles in tungsten restricts grain growth resulting in better high temperature creep resistance. The higher recrystallization temperature allows measurements to be made over a wider range of temperatures at a relatively constant grain size

  1. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Science.gov (United States)

    2010-07-01

    ... zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL... POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This subpart applies to discharges of pollutants to waters of the...

  2. 40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.

    Science.gov (United States)

    2010-07-01

    ... primary zirconium and hafnium subcategory. 421.330 Section 421.330 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Zirconium and Hafnium Subcategory § 421.330 Applicability: Description of the primary zirconium and hafnium subcategory. The provisions of this subpart are applicable to discharges resulting...

  3. Ground-state structures of Hafnium clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)

    2015-04-24

    Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.

  4. Hafnium carbide nanocrystal chains for field emitters

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang

    2014-01-01

    A hafnium carbide (HfC) nanostructure, i.e., HfC nanocrystal chain, was synthesized by a chemical vapor deposition (CVD) method. X-ray diffractometer, field-emission scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray spectrometer were employed to characterize the product. The synthesized one-dimensional (1D) nanostructures with many faceted octahedral nanocrystals possess diameters of tens of nanometers to 500 nm and lengths of a few microns. The chain-like structures possess a single crystalline structure and preferential growth direction along the [1 0 0] crystal orientation. The growth of the chains occurred through the vapor–liquid–solid process along with a negative-feedback mechanism. The field emission (FE) properties of the HfC nanocrystal chains as the cold cathode emitters were examined. The HfC nanocrystal chains display good FE properties with a low turn-on field of about 3.9 V μm −1 and a high field enhancement factor of 2157, implying potential applications in vacuum microelectronics.

  5. Use of hafnium in control bars of nuclear reactors

    International Nuclear Information System (INIS)

    Ramirez S, J.R.; Alonso V, G.

    2003-01-01

    Recently the use of hafnium as neutron absorber material in nuclear reactors has been reason of investigation by virtue of that this material has nuclear properties as to the neutrons absorption and structural that can prolong the useful life of the control mechanisms of the nuclear reactors. In this work some of those more significant hafnium properties are presented like nuclear material. Also there are presented calculations carried out with the HELIOS code for fuel cells of uranium oxide and of uranium and plutonium mixed oxides under controlled conditions with conventional bars of boron carbide and also with similar bars to which are substituted the absorbent material by metallic hafnium, the results are presented in this work. (Author)

  6. Analytical study of zirconium and hafnium α-hydroxy carboxylates

    International Nuclear Information System (INIS)

    Terra, V.R.

    1991-01-01

    The analytical study of zirconium and hafnium α-hydroxy carboxylates was described. For this purpose dl-mandelic, dl-p-bromo mandelic, dl-2-naphthyl glycolic, and benzilic acids were prepared. These were used in conjunction with glycolic, dl-lactic, dl-2-hydroxy isovaleric, dl-2-hydroxy hexanoic, and dl-2-hydroxy dodecanoic acids in order to synthesize the zirconium(IV) and hafnium(IV) tetrakis(α-hydroxy carboxylates). The compounds were characterized by melting point determination, infrared spectroscopy, thermogravimetric analysis, calcination to oxides and X-ray diffractometry by the powder method. (C.G.C)

  7. High temperature evaporation of titanium, zirconium and hafnium carbides

    International Nuclear Information System (INIS)

    Gusev, A.I.; Rempel', A.A.

    1991-01-01

    Evaporation of cubic nonstoichiometric carbides of titanium, zirconium and hafnium in a comparatively low-temperature interval (1800-2700) with detailed crystallochemical sample certification is studied. Titanium carbide is characterized by the maximum evaporation rate: at T>2300 K it loses 3% of sample mass during an hour and at T>2400 K titanium carbide evaporation becomes extremely rapid. Zirconium and hafnium carbide evaporation rates are several times lower than titanium carbide evaporation rates at similar temperatures. Partial pressures of metals and carbon over the carbides studied are calculated on the base of evaporation rates

  8. Preparation of complexes of zirconium and hafnium tetrachlorides with phosphorus oxychloride

    International Nuclear Information System (INIS)

    McLaughlin, D.F.

    1989-01-01

    This patent describes an improvement in a method for separating hafnium tetrachloride from zirconium tetrachloride where a complex of zirconium-hafnium tetrachlorides and phosphorus oxychloride is prepared from zirconium-hafnium tetrachlorides and the complex of zirconium-hafnium tetrachlorides and phosphorus oxychloride is introduced into a distillation column, which distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and where a hafnium tetrachloride enriched stream is taken from the top of the column and a zirconium enriched tetrachloride stream is taken from the bottom of the column. The improvement comprising: prepurifying the zirconium-hafnium tetrachlorides, prior to preparation of the complex and introduction of the complex into a distillation column, to substantially eliminate iron chloride from the zirconium hafnium tetrachlorides, whereby buildup or iron chloride in the distillation column and in the reboiler is substantially eliminated and the column can be operated in a continuous, stable and efficient manner

  9. Separation process of zirconium and hafnium; Procede de separation du zirconium et du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Hure, J; Saint-James, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    About the separation different processes of zirconium-hafnium, the extraction by solvent in cross-current is the most easily the process usable on an industrial scale. It uses tributyl phosphate as solvent, diluted with white spirit to facilitate the decanting. Some exploratory tests showed that nitric environment seemed the most favorable for extraction; but a lot of other factors intervene in the separation process. We studied the influence of the acidity successively, the NO{sub 3}{sup -} ions concentration, the role of the cation coming with NO{sub 3}{sup -}, as well as the influence of the concentration of zirconium in the solution on the separation coefficient {beta} = {alpha}{sub Zr} / {alpha}{sub Hf}. (M.B.) [French] Des differents procedes de separation zirconium-hafnium, l'extraction par solvant en contre-courant est le procede le plus facilement utilisable a l'echelle industrielle. On utilise comme solvant le phosphate de tributyle, dilue avec du white spirit pour faciliter les decantations. Des essais preliminaires ont montre que le milieu nitrique semblait le plus favorable a l'extraction; mais beaucoup d'autres facteurs interviennent dans le processus de separation. Nous avons etudie successivement l'influence de l'acidite, celle de la concentration en ions NO{sub 3}{sup -}, le role du cation accompagnant NO{sub 3}{sup -}, ainsi que l'influence de la concentration en zirconium de la solution sur le coefficient de separation {beta} = {alpha}{sub Zr} / {alpha}{sub Hf}. (MB)

  10. Separation of zirconium and hafnium using paper distribution chromatography

    International Nuclear Information System (INIS)

    Lebedeva, G.G.; Viktorova, M.E.

    1981-01-01

    A method is suggested of chromatographic separation of zirconium and hafnium in a CCl 4 -tributyl phosphate system (1:9) containing KCl as a salting-out agent in 5 M HNO 3 at 28-30 deg C. Zr and Hf are deterfmined in articiial mixtures under optimal chromatography conditions using visual colorimetry [ru

  11. X-Ray Photoemission Study of the Oxidation of Hafnium

    International Nuclear Information System (INIS)

    Chourasia, R.; Hickman, J.L.; Miller, R.L.; Nixon, G.A.; Seabolt, M.A.

    2011-01-01

    About 20 angstrom of hafnium were deposited on silicon substrates using the electron beam evaporation technique. Two types of samples were investigated. In one type, the substrate was kept at the ambient temperature. After the deposition, the substrate temperature was increased to 100, 200, and 300 degree C. In the other type, the substrate temperature was held fixed at some value during the deposition. For this type, the substrate temperatures used were 100, 200, 300, 400, 500, 550, and 600 degree C. The samples were characterized in situ by the technique of X-ray photoelectron spectroscopy. No trace of elemental hafnium is observed in the deposited overlayer. Also, there is no evidence of any chemical reactivity between the overlayer and the silicon substrate over the temperature range used. The hafnium overlayer shows a mixture of the dioxide and the suboxide. The ratio of the suboxide to dioxide is observed to be more in the first type of samples. The spectral data indicate that hafnium has a strong affinity for oxygen. The overlayer gets completely oxidized to form HfO 2 at substrate temperature around 300 degree C for the first type of samples and at substrate temperature greater than 550 degree C for the second type

  12. X-Ray Photoemission Study of the Oxidation of Hafnium

    Directory of Open Access Journals (Sweden)

    A. R. Chourasia

    2009-01-01

    Full Text Available About 20 Å of hafnium were deposited on silicon substrates using the electron beam evaporation technique. Two types of samples were investigated. In one type, the substrate was kept at the ambient temperature. After the deposition, the substrate temperature was increased to 100, 200, and 300∘C. In the other type, the substrate temperature was held fixed at some value during the deposition. For this type, the substrate temperatures used were 100, 200, 300, 400, 500, 550, and 600∘C. The samples were characterized in situ by the technique of X-ray photoelectron spectroscopy. No trace of elemental hafnium is observed in the deposited overlayer. Also, there is no evidence of any chemical reactivity between the overlayer and the silicon substrate over the temperature range used. The hafnium overlayer shows a mixture of the dioxide and the suboxide. The ratio of the suboxide to dioxide is observed to be more in the first type of samples. The spectral data indicate that hafnium has a strong affinity for oxygen. The overlayer gets completely oxidized to form HfO2 at substrate temperature around 300∘C for the first type of samples and at substrate temperature greater than 550∘C for the second type.

  13. Modelling of Zirconium and Hafnium separation using continuous annular chromatography

    International Nuclear Information System (INIS)

    Moch-Setyadji; Endang Susiantini

    2014-01-01

    Nuclear degrees of zirconium in the form of a metal alloy is the main material for fuel cladding of NPP. Zirconium is also used as sheathing UO 2 kernel in the form of ZrC as a substitute of SiC in the fuel elements of High Temperature Reactor (HTR). Difficulty separating hafnium from zirconium because it has a lot of similarities in the chemical properties of Zr and Hf. Annular chromatography is a device that can be used for separating of zirconium and hafnium to obtain zirconium nuclear grade. Therefore, it is necessary to construct the mathematical modelling that can describe the separation of zirconium and hafnium in the annular chromatography containing anion resin dowex-1X8. The aim of research is to perform separation simulation by using the equilibrium model and mass transfer coefficient resulted from research. Zr and Hf feed used in this research were 26 and 1 g/l, respectively. Height of resin (L), angular velocity (ω) and the superficial flow rate (uz) was varied to determine the effect of each parameter on the separation of Zr and Hf. By using Kd and Dv values resulted previous research. Simulation results showed that zirconium and hafnium can be separated using a continuous annular chromatography with high resin (long bed) 50 cm, superficial flow rate of 0.001 cm/s, the rotation speed of 0.006 rad/min and 20 cm diameter annular. In these conditions the results obtained zirconium concentration of 10,303.226 g/m 3 and hafnium concentration of 12.324 g/m 3 (ppm). (author)

  14. 46 CFR 176.802 - Hull.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hull. 176.802 Section 176.802 Shipping COAST GUARD... CERTIFICATION Material Inspections § 176.802 Hull. (a) At each initial and subsequent inspection for... ready for inspections of the hull structure and its appurtenances, including the following: (1...

  15. 21 CFR 211.176 - Penicillin contamination.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Penicillin contamination. 211.176 Section 211.176 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Laboratory Controls § 211.176...

  16. 49 CFR 176.162 - Security.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Security. 176.162 Section 176.162 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION... Class 1 (Explosive) Materials Precautions During Loading and Unloading § 176.162 Security. A responsible...

  17. 49 CFR 176.24 - Shipping papers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Shipping papers. 176.24 Section 176.24... Requirements § 176.24 Shipping papers. (a) A person may not accept a hazardous material for transportation or transport a hazardous material by vessel unless that person has received a shipping paper prepared in...

  18. 49 CFR 176.120 - Lightning protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Lightning protection. 176.120 Section 176.120 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Requirements for Class 1 (Explosive) Materials Stowage § 176.120 Lightning protection. A lightning conductor...

  19. 46 CFR 176.814 - Steering systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.814 Steering systems. At each initial and subsequent inspection for certification the owner or managing operator shall be prepared to test the steering systems of...

  20. 49 CFR 176.715 - Contamination control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Contamination control. 176.715 Section 176.715... Requirements for Radioactive Materials § 176.715 Contamination control. Each hold, compartment, or deck area... the removable (non-fixed) radioactive surface contamination is not greater than the limits prescribed...

  1. 46 CFR 176.810 - Fire protection.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Fire protection. 176.810 Section 176.810 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.810 Fire protection. (a) At each initial and... and have the vessel ready for inspection of its fire protection equipment, including the following: (1...

  2. 46 CFR 160.176-9 - Construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Construction. 160.176-9 Section 160.176-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Inflatable Lifejackets § 160.176-9 Construction. (a) General...

  3. 46 CFR 160.176-11 - Performance.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Performance. 160.176-11 Section 160.176-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Inflatable Lifejackets § 160.176-11 Performance. (a) General...

  4. Electronic properties of hafnium oxide: A contribution from defects and traps

    Energy Technology Data Exchange (ETDEWEB)

    Gritsenko, Vladimir A., E-mail: grits@isp.nsc.ru; Perevalov, Timofey V.; Islamov, Damir R., E-mail: damir@isp.nsc.ru

    2016-02-15

    In the present article, we give a review of modern data and latest achievements pertaining to the study of electronic properties of oxygen vacancies in hafnium oxide. Hafnium oxide is a key dielectric for use in many advanced silicon devices. Oxygen vacancies in hafnium oxide largely determine the electronic properties of the material. We show that the electronic transitions between the states due to oxygen vacancies largely determine the optical absorption and luminescent properties of hafnium oxide. We discuss the role of oxygen vacancies as traps that facilitate charge transport in hafnium oxide films. Also, we demonstrate the fact that the electrical conductivity in hafnium oxide is controlled by the phonon-assisted tunnelling of charge carriers between traps that were identified as oxygen vacancies.

  5. Method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream

    International Nuclear Information System (INIS)

    Snyder, T.S.; Stolz, R.A.

    1992-01-01

    This patent describes a method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream from a sand chlorinator in which the silicon and metals present in sand fed to the chlorinator are converted to chlorides at temperatures over about 800 degrees C. It comprises cooling a vapor stream from a sand chlorinator, the vapor stream containing principally silicon tetrachloride, zirconium tetrachloride, and hafnium tetrachloride contaminated with ferric chloride, to a temperature of from about 335 degrees C to about 600 degrees C; flowing the vapor stream through a gaseous diffusion separative barrier to produce a silicon tetrachloride-containing vapor stream concentrated in zirconium tetrachloride and hafnium tetrachloride and a silicon tetrachloride-containing vapor stream depleted in zirconium tetrachloride and hafnium tetrachloride; adsorbing the ferric chloride in the separative barrier; and recovering the silicon tetrachloride stream concentrated in zirconium tetrachloride and hafnium tetrachloride separately from the silicon tetrachloride stream depleted in zirconium tetrachloride and hafnium tetrachloride

  6. Synthesis of Hafnium-Based Ceramic Materials for Ultra-High Temperature Aerospace Applications

    Science.gov (United States)

    Johnson, Sylvia; Feldman, Jay

    2004-01-01

    This project involved the synthesis of hafnium (Hf)-based ceramic powders and Hf-based precursor solutions that were suitable for preparation of Hf-based ceramics. The Hf-based ceramic materials of interest in this project were hafnium carbide (with nominal composition HE) and hafnium dioxide (HfO2). The materials were prepared at Georgia Institute of Technology and then supplied to research collaborators Dr. Sylvia Johnson and Dr. Jay Feldman) at NASA Ames Research Center.

  7. 176Lu: Cosmic clock or stellar thermometer

    International Nuclear Information System (INIS)

    Ward, R.A.; Beer, H.; Kaeppeler, F.; Wisshak, K.

    1980-12-01

    We quantitatively examine the various experimental and theoretical aspects of the stellar synthesis of the long-lived ground state of 176 Lu (3.6 x 10 10 y). We discuss the various regimes of stellar temperature and free-neutron density in which either: (i) the internal electromagnetic couplings between 176 Lusup(o) and 176 Lusup(m) (3.68 hours) are sufficiently slow that they may be treated as separate nuclei, or (ii) the internal couplings are rapidly able to establish thermal equilibrium between 176 Lusup(o) and 176 Lusup(m). (orig.)

  8. Elaboration and characterisation of yttrium oxide and hafnium oxide powders by the sol-gel process

    International Nuclear Information System (INIS)

    Hours, T.

    1988-01-01

    The two classical sol-gel processes, colloidal and polymeric are studied for the preparation of yttrium oxide and hafnium oxide high performance powders. In the colloidal process, controlled and reproducible conditions for the preparation of yttrium oxide and hafnium oxide sols from salts or alkoxides are developed and the hydrothermal synthesis monodisperse hafnium oxide colloids is studied. The polymeric process is studied with hafnium ethyl-hexylate, hydrolysis kinetics for controlled preparation of sols and gels is investigated. Each step of preparation is detailed and powders obtained are characterized [fr

  9. Design and fabrication of hafnium tube to control the power of the irradiation test fuel in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Lee, C. B.; Kim, Y. M.; Yang, Y. S.; Jung, Y. H

    2003-05-01

    For the irradiation test at HANARO, non-instrumentation capsule was manufactured and hafnium tube was used to control LHGR of HANARO. Hafnium tube can control the irradiation condition of HANARO similar to that of commercial reactor. Hafnium tube thickness was determined by the LHGR calculated at OR-4 irradiation hole to be installed the non-instrumented capsule. To fabricate the hafnium tube with hafnium plate, the fabrication method was determined by using the hafnium mechanical properties. And the tensile strength of hafnium was confirmed by tensile test. This report is confirmed the LHGR control at the OR-4 and the Hafnium fabrication for in used which the AFPCAP non-instrumented irradiation capsule.

  10. Pentamethylcyclopentadienyl Zirconium and Hafnium Polyhydride Complexes : Synthesis, Structure, and Reactivity

    NARCIS (Netherlands)

    Visser, Cindy; Hende, Johannes R. van den; Meetsma, Auke; Hessen, Bart; Teuben, Jan H.

    2001-01-01

    The half-sandwich zirconium and hafnium N,N-dimethylaminopropyl complexes Cp*M[(CH2)3NMe2]Cl2 (Cp* = η5-C5Me5, M = Zr, 1; Hf, 2) and Cp*M[(CH2)3NMe2]2Cl (M = Zr, 3; Hf, 4) were synthesized by mono- or dialkylation of Cp*MCl3 with the corresponding alkyllithium and Grignard reagents. Hydrogenolysis

  11. Separation of zirconium from hafnium by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Felipe, Elaine C.B.; Palhares, Hugo G.; Ladeira, Ana Claudia Q., E-mail: elainecfelipe@yahoo.com.br, E-mail: hugopalhares@gmail.com, E-mail: ana.ladeira@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Zirconium and hafnium are two of the most important metals for the nuclear industry. Hafnium occurs in all zirconium ores usually in the range 2 - 3%. However, for the most nuclear industry applications, it is necessary to use a zirconium of extremely pure level. The current work consists in the separation of zirconium and hafnium by the ion exchange method in order to obtain a zirconium concentrate of high purity. The zirconium and hafnium liquors were produced from the leaching of the Zr(OH){sub 4} and Hf(OH){sub 4} with nitric acid for 24 hours. From these two liquors it was prepared one solution containing 7.5 x 10{sup -2} mol L{sup -1} of Zr and 5.8 x 10{sup -3} mol L{sup -1} of Hf with acidity of 1 M. Ion exchange experiments were carried out in batch with the resins Dowex 50WX4, Dowex 50WX8 100, Dowex 50WX8 50, Amberlite IR-120 and Marathon C at constant temperature 28 deg C. Other variables such as, acidity and agitation were kept constant. The data were adjusted to Langmuir equation in order to calculate the maximum loading capacity (q{sub max}) of the resins, the distribution coefficient (K{sub d}) for Zr and Hf and the separation factor (α{sub Hf}{sup Zr} ). The results of maximum loading capacity (q{sub max}) for Zr and Hf, in mmol g{sup -}1, showed that the most suitable resins for columns experiments are: Dowex 50WX4 50 (q{sub max} Z{sub r} = 2.21, Hf = 0.18), Dowex 50WX8 50 (q{sub max} Zr = 1.89, Hf = 0.13) and Amberlite (q{sub max} Zr = 1.64, Hf = 0.12). However, separations factors, α{sub Hf}{sup Zr}, showed that the resins are not selective. (author)

  12. Evolution of the hafnium isotopic composition in the RBMK reactor

    International Nuclear Information System (INIS)

    Jurkevicius, A.; Remeikis, V.

    2002-01-01

    The isotopic composition of hafnium in the radial neutron flux sensor of the RBMK-1500 reactor, the rates of the neutron absorption on Hf isotopes and the neutron spectrum in the sensor were numerically modeled. The sequence SAS2 (Shielding Analysis Sequence) program from the package SCALE 4.4A and the HELIOS code system were used for calculations. It has been obtained that the overall neutron absorption rates in hafnium for the sensors located in the 2.4 % and 2.6 % enrichment uranium-erbium nuclear fuel assemblies are by 16 % and 19 % lower than in the 2.0 % enrichment uranium nuclear fuel assemblies. The overall neutron absorption rate in hafnium decreases 2.70-2.75 times due to the sensor burnup to 5800 MW d. The sensitivity of the Hf sensors to the thermal neutron flux increases twice due to the nuclear fuel assembly burnup to 3000 MW d. The corrective factors ξ d (I) at the different integral current I of the sensors and ξ td (E) at the different burnup E of the nuclear fuel assemblies were calculated. The obtained dependence ξ d (I) calculated numerically was compared to the experimental one determined by comparing signals of the fresh sensor and the sensor with the integral current I and by processing repeated calibration results of Hf sensors in RBMK-1500 reactors. The relative relationship coefficients K T (T FA ) were found for all RBMK-1500 nuclear fuel types. (author)

  13. Recovery of hafnium radioisotopes from a proton irradiated tantalum target

    International Nuclear Information System (INIS)

    Taylor, W.A.; Garcia, J.G.; Hamilton, V.T.; Heaton, R.C.; Jamriska, D.J.; Ott, M.A.; Philips, D.R.; Radzinski, S.D.

    1998-01-01

    The 178m2 Hf nucleus, with its long half-life (31 y) and high-spin isomeric state (16 + ) is desired for new and exotic nuclear physics studies. The Los Alamos Radioisotope Program irradiated a kilogram of natural tantalum at the Los Alamos Meson Physics Facility in early 1981. After fifteen years of decay, this target was ideal for the recovery of 178m2 Hf. There was more than a millicurie of 178m2 Hf produced during this irradiation and there has been a sufficient period of time for most of the other hafnium radioisotopes to decayed away. Traditionally, separation techniques for recovering hafnium isotopes from tantalum targets employ solvent extractions with reagents that are considered hazardous. These techniques are no longer condoned because they generate a mixed-waste (radioactive and hazardous components) that can not be treated for disposal. In this paper we describe a new and unique procedure for the recovery of hafnium radioisotopes from a highly radioactive, proton irradiated, tantalum target using reagents that do not contribute a hazardous waste component. (author)

  14. Zirconium and hafnium in the southeastern Atlantic States

    Science.gov (United States)

    Mertie, J.B.

    1958-01-01

    The principal source of zirconium and hafnium is zircon, though a minor source is baddeleyite, mined only in Brazil. Zircon is an accessory mineral in igneous, metamorphic, and sedimentary rocks, but rarely occurs in hardrock in minable quantities. The principal sources of zircon are therefore alluvial deposits, which are mined in many countries of five continents. The principal commercial deposits in the United States are in Florida, though others exist elsewhere in the southeastern Coastal Plain. The evidence indicates that conditions for the accumulation of workable deposits of heavy minerals were more favorable during the interglacial stages of the Pleistocene epoch than during Recent time. Therefore detrital ores of large volume and high tenor are more likely to be found in the terrace deposits than along the present beaches. Other concentrations of heavy minerals, however, are possible at favored sites close to the Fall Line where the Tuscaloosa formation rests upon the crystalline rocks of the Piedmont province. A score of heavy and semiheavy minerals occur in the detrital deposits of Florida, but the principal salable minerals are ilmenite, leucoxene, rutile, and zircon, though monazite and staurolite are saved at some mining plants. Commercial deposits of heavy minerals are generally required to have a tenor of 4 percent, though ores with a lower tenor can be mined at a profit if the content of monazite is notably high. The percentages of zircon in the concentrates ranges from 10 to 16 percent, and in eastern Florida from 13 to 15 percent. Thus the tenor in zircon of the ore-bearing sands ranges from 0.4 to 0.6 percent. The content of hafnium in zircon is immaterial for many uses, but for some purposes very high or very low tenors in hafnium are required. Alluvial zircon cannot be separated into such varieties, which, if needed, must be obtained from sources in bedrock. It thus becomes necessary to determine the Hf : Zr ratios in zircon from many kinds of

  15. On the stabilization of niobium(V) solutions by zirconium(IV) and hafnium(IV)

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    Niobium cannot be separated from zirconium or hafnium when these elements occur together in solution with common anions such as chloride and sulphate. This is ascribed to the co-polymerization of niobium(V) and the hydrolysed ionic species of zirconium(IV) and hafnium(IV) to form colloidal...

  16. Use of X-ray fluorescence analysis for the determination of hafnium in zircalloys

    International Nuclear Information System (INIS)

    Sato, I.M.; Salvador, V.L.R.; Lordello, A.R.

    1985-01-01

    The determination of hafnium at trace levels (ppm) in the presence of zirconium by X-ray fluorescence technique is presented. The samples were prepared in the form of double-layer pellets, with boric acid as the binding material. The most sensitive first order line of hafnium HfLα (0.157 nm), which is used analyticaly, has approximately 67% overlapping with second order line of zirconium ZrKα 1 , (0.079 nm). As the excitation potencial of zirconium is larger than hafnium, the best condition was selected, so that the interference of zirconium intensity would not be significant in hafnium analytical line. The method allowed the determination of hafnium above 5.0 ppm (LLd = 1.5 ppm) with an accuracy of less than 10%. (Author) [pt

  17. Preparation of complexes of zirconium and hafnium tetrachlorides with phosphorus oxychloride

    International Nuclear Information System (INIS)

    Snyder, T.S.; Stoltz, R.A.

    1989-01-01

    This patent describes an improvement in a method for separating hafnium chloride from zirconium chloride using a distillation column, with a hafnium chloride enriched vapor stream taken from the top of the column and a zirconium enriched chloride stream taken from the bottom of the column. The improvement comprising: purifying the zirconium-hafnium chloride in a molten salt purification vessel prior to or after introduction into the distillation column to substantially eliminate iron chloride from the zirconium-hafnium chloride by at least periodically removing iron chloride from the molten salt purification vessel by electrochemically plating iron onto an electrode in the molten salt purification vessel. The molten salt in the molten salt purification vessel consisting essentially of a mixture of chlorides selected from the group consisting of alkali metals, alkaline earth metals, zirconium, hafnium, aluminum, manganese, and zinc

  18. 27 CFR 17.6 - Signature authority.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Signature authority. 17.6... PRODUCTS General Provisions § 17.6 Signature authority. No claim, bond, tax return, or other required... other proper notification of signature authority has been filed with the TTB office where the required...

  19. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  20. Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

    Science.gov (United States)

    Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

    2017-07-01

    In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

  1. Corrosion potentials of hafnium in molten alkaline-earth metal chlorides

    International Nuclear Information System (INIS)

    Kovalik, O.Yu.; Tkhaj, V.D.

    2000-01-01

    Corrosion potentials of hafnium in molten calcium, strontium and barium chlorides are measured and their temperature dependences are determined. It is stated that the corrosion potential of hafnium becomes more electropositive with an increase of the environment temperature. If the temperature is the same the potential shifts to the interval of more electronegative values in the row of CaCl 2 , SrCl 2 , BaCl 2 which corresponds to a lesser corrosion rate in environments positioned from left to right. the comparison of hafnium corrosion potentials with previously measured values for titanium and zirconium shows that a metal activity decrease results in a more electronegative corrosion potential [ru

  2. Hafnium-Based Contrast Agents for X-ray Computed Tomography.

    Science.gov (United States)

    Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

    2017-05-15

    Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

  3. Solvent extraction of zirconium and hafnium using MIBK-HSCN-HCL process

    International Nuclear Information System (INIS)

    Borges, J.A.L.; Cunha, O.G.C. da

    1985-01-01

    The separation process of zirconium and hafnium, using MIBK as extractant in a set of mixer-settler is described. The chemical analysis was done by X-ray fluorescence and emission spectrography. (Author) [pt

  4. Hafnium as a prospective absorber for VVER-1000 reactors of Ukraine

    International Nuclear Information System (INIS)

    Afanas'ev, A.A.; Konotop, Yu.F.; Odejchuk, N.L.

    2000-01-01

    Nuclear-physical parameters of hafnium having in mind its use as an absorber, are considered. Technical aspects of Hf production are exposed. Use of B 4 C/Hf absorber is twice cheaper than a standard one

  5. Spectrofluorimetric determination of hafnium and zirconium with 3,7-dihydroxyflavone

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Takushi; Suzuki, Osamu; Seuzuki, Tetsuo; Murata, Akira

    1986-04-01

    The absorptive and fluorescent characteristics of the hafnium and zirconium complexes of 3-hydroxyflavone and its 12 hydroxy and methoxy derivatives have been studied. The fluorescence of the 1:1 hafnium - 3,7-dihydroxyflavone complex (lambdasub(ex.)397 nm,lambdasub(em.) 465 nm) in 3 M hydrochloric acid has been used to determine 2-40 ng ml/sup -1/ of hafnium. The fluorescence of the 1:1 zirconium - 3,7-dihydroxyflavone complex (lambdasub(ex.) 395 nm, lambda sub(em.) 465 nm) at pH 2.0 in 0.02 M sulphate solution has been used to determine 2-40 ng ml/sup -1/ of zirconium. These methods are very sensitive and can be used for the simultaneous determination of hafnium and zirconium with an error of about 5%.

  6. Electronic structure of pentacene on hafnium studied by ultraviolet photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Kang, Seong Jun; Yi, Yeon Jin; Kim, Chung Yi; Whang, Chung Nam

    2005-01-01

    The electronic structure of pentacene on hafnium, which is a low work function metal, was analyzed by using ultraviolet photoelectron spectroscopy. The energy level alignment was studied by using the onset of the highest occupied molecular orbital level and the shift of the vacuum level of the pentacene layer, which was deposited on a clean hafnium surface in a stepwise manner. The measured onset of the highest occupied molecular orbital energy level was 1.52 eV from the Fermi level of hafnium. The vacuum level was shifted 0.28 eV toward higher binding energy with additional pentacene layers, which means an interfacial dipole exists at the interface between pentacene and hafnium. We confirm that a small electron injection barrier can be achieved by inserting a low work function metal in a pentacene thin-film transistor.

  7. Compositional characterization of hafnium alloy used as control rod material in nuclear reactor

    International Nuclear Information System (INIS)

    Sharma, P.K.; Bassan, M.K.T.; Avhad, D.K.; Singhal, R.K.

    2014-01-01

    Hafnium (Hf) is a heavy, steel-gray metal in the reactive metals group that is very closely related to zirconium (Zr) and forms a continuous solid-solution at all concentrations of zirconium and hafnium. Hafnium occurs naturally with zirconium at a ratio of approximately 1:50 and is produced exclusively as a co-product of nuclear-grade zirconium. It is used in a variety of applications where few substitutes are available. Thus with its relatively high thermal neutron absorption cross-section, hafnium's biggest application is as control rod material in nuclear reactors. During this work, major (Zirconium (Zr), Cobalt (Co) and Molybdenum (Mo)) and trace ((Iron (Fe), Nickel (Ni) and Titanium (Ti)) elements were measured in the bulk matrices of Hf. These materials are also associated with other impurities such as O, N, H etc.

  8. Evaluation of thermodynamic data on zirconium and hafnium halides and oxyhalides by means of transport experiments

    International Nuclear Information System (INIS)

    Dittmer, G.; Niemann, U.

    1987-01-01

    A consistent set of thermodynamic data for zirconium and hafnium halides, oxides and oxyhalides was achieved. It was found that formation enthalpies of gaseous compounds could be derived from solubility measurements together with theoretical estimations and a revision of literature data. Free energy functions were calculated employing statistical mechanics. Data for liquid and solid compounds were obtained via sublimation and vaporization data. Chemical equilibria of zirconium and hafnium with halogens are discussed. 51 refs.; 16 figs.; 14 tabs

  9. Investigation of chlorination of zirconium and hafnium and their compounds in discharge from hollow cathode

    International Nuclear Information System (INIS)

    Ioffe, R.B.; Korovin, Yu.I.

    1978-01-01

    The possibility is investigated of chlorinating various zirconium and hafnium compounds (metal, oxide, carbide) in a hot discharge from a hollow cathode with various chlorinating reagents: copper monochloride, nickel chloride, magnesium chloride, for the purpose of accelerating their entrance into the excitation zone. It has been shown thermodynamically and experimentally that chlorination of metal zirconium and hafnium and their carbides with copper monochloride in hot hollow cathode conditions provides a sharp increase in the intensity of the lines of these elements

  10. Knight shift in scandium and its alloys with hafnium and titanium

    International Nuclear Information System (INIS)

    Chachkhiani, Z.B.; Chechernikov, V.I.; Martynova, L.F.; Nidel'ko, V.I.; Chachkhiani, L.G.; Georgadze, G.S.

    1981-01-01

    Results of the investigation of NMR on 45 Sc nuclei and magnetic susceptibility of scandium and its solid solutions with titanium and hafnium are presented. It is shown that the existing hybridization of S and d zones in pure scandium and its alloys with titanium and hafnium affects the Knight shift reducing the value of the contact contribution. The temperature behaviour of the Knight shift from the temperature dependence and spin susceptibility of collectivized d electrons [ru

  11. Application of hafnium hydride control rod to large sodium cooled fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Kazumi, E-mail: kazumi_ikeda@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Moriwaki, Hiroyuki, E-mail: hiroyuki_moriwaki@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Ohkubo, Yoshiyuki, E-mail: yoshiyuki_okubo@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Iwasaki, Tomohiko, E-mail: tomohiko.iwasaki@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi-ken 980-8579 (Japan); Konashi, Kenji, E-mail: konashi@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Narita-cho, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki-ken 311-1313 (Japan)

    2014-10-15

    Highlights: • Application of hafnium hydride control rod to large sodium cooled fast breeder reactor. • This paper treats application of an innovative hafnium hydride control rod to a large sodium cooled fast breeder reactor. • Hydrogen absorption triples the reactivity worth by neutron spectrum shift at H/Hf ratio of 1.3. • Lifetime of the control rod quadruples because produced daughters of hafnium isotopes are absorbers. • Nuclear and thermal hydraulic characteristics of the reactor are as good as or better than B-10 enriched boron carbide. - Abstract: This study treats the feasibility of long-lived hafnium hydride control rod in a large sodium-cooled fast breeder reactor by nuclear and thermal analyses. According to the nuclear calculations, it is found that hydrogen absorption of hafnium triples the reactivity by the neutron spectrum shift at the H/Hf ratio of 1.3, and a hafnium transmutation mechanism that produced daughters are absorbers quadruples the lifetime due to a low incineration rate of absorbing nuclides under irradiation. That is to say, the control rod can function well for a long time because an irradiation of 2400 EFPD reduces the reactivity by only 4%. The calculation also reveals that the hafnium hydride control rod can apply to the reactor in that nuclear and thermal characteristics become as good as or better than 80% B-10 enriched boron carbide. For example, the maximum linear heat rate becomes 3% lower. Owing to the better power distribution, the required flow rate decreases approximately by 1%. Consequently, it is concluded on desk analyses that the long lived hafnium hydride control rod is feasible in the large sodium-cooled fast breeder reactor.

  12. Dielectric response and ac conductivity analysis of hafnium oxide nanopowder

    International Nuclear Information System (INIS)

    Karahaliou, P K; Xanthopoulos, N; Krontiras, C A; Georga, S N

    2012-01-01

    The dielectric response of hafnium oxide nanopowder was studied in the frequency range of 10 -2 -10 6 MHz and in the temperature range of 20-180 °C. Broadband dielectric spectroscopy was applied and the experimental results were analyzed and discussed using the electric modulus (M*) and alternating current (ac) conductivity formalisms. The analyses of the dc conductivity and electric modulus data revealed the presence of mechanisms which are thermally activated, both with almost the same activation energy of 1.01 eV. A fitting procedure involving the superposition of the thermally activated dc conductivity, the universal dielectric responce and the near constant loss terms has been used to describe the frequency evolution of the real part of the specific electrical conductivity. The conductivity master curve was obtained, suggesting that the time-temperature superposition principle applies for the studied system, thus implying that the conductivity mechanisms are temperature independent.

  13. Amorphous Hafnium-Indium-Zinc Oxide Semiconductor Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Sheng-Po Chang

    2012-01-01

    Full Text Available We reported on the performance and electrical properties of co-sputtering-processed amorphous hafnium-indium-zinc oxide (α-HfIZO thin film transistors (TFTs. Co-sputtering-processed α-HfIZO thin films have shown an amorphous phase in nature. We could modulate the In, Hf, and Zn components by changing the co-sputtering power. Additionally, the chemical composition of α-HfIZO had a significant effect on reliability, hysteresis, field-effect mobility (μFE, carrier concentration, and subthreshold swing (S of the device. Our results indicated that we could successfully and easily fabricate α-HfIZO TFTs with excellent performance by the co-sputtering process. Co-sputtering-processed α-HfIZO TFTs were fabricated with an on/off current ratio of ~106, higher mobility, and a subthreshold slope as steep as 0.55 V/dec.

  14. Determination of hafnium with the inductively coupled plasma (ICP)

    International Nuclear Information System (INIS)

    Wuensch, G.; Pose, K.

    1985-01-01

    The relative intensities of 198 hafnium lines in the Ar-ICP are listed. Spectral interference tables are given for the 9 analytically best lines, covering the range of +-60 pm around the Hf-lines. They include measured (not calculated) data of the interferent equivalent concentrations (IEC) and the critical concentration ratios (CCR) for 115 lines of all 34 possibly interfering elements. In many cases, these IEC- or CCR-data differ by 1 or 2 orders of magnitude from those calculated from intensities observed in the NBS-copper arc. Since no intense Hf-line is free from spectral interferences, examples are given for the calculation of the most suitable line for a known matrix. (orig.) [de

  15. Separation of zirconium--hafnium by nitride precipitation

    International Nuclear Information System (INIS)

    Anderson, R.N.; Parlee, N.A.

    1977-01-01

    A method is described for the separation of a light reactive metal (e.g., zirconium) from a heavy reactive metal (e.g., hafnium) by forming insoluble nitrides of the metals in a molten metal solvent (e.g., copper) inert to nitrogen and having a suitable density for the light metal nitride to form a separate phase in the upper portion of the solvent and for the heavy metal nitride to form a separate phase in the lower portion of the solvent. Nitriding is performed by maintaining a nitrogen-containing atmosphere over the bath. The light and heavy metals may be an oxide mixture and carbothermically reduced to metal form in the same bath used for nitriding. The nitrides are then separately removed and decomposed to form the desired separate metals. 16 claims, 1 figure

  16. Synthesis and characterization of hafnium oxide for luminescent applications

    International Nuclear Information System (INIS)

    Guzman Mendoza, J.; Aguilar Frutis, M.A.; Flores, G. Alarcon; Garcia Hipolito, M.; Azorin Nieto, J.; Rivera Montalvo, T.; Falcony, C.

    2008-01-01

    Full text: Hafnium oxide (HfO 2 ) is a material with a wide range of possible technological applications because it's chemical and physical properties such as high melting point, high chemical stability, high refraction index, high dielectric constant and hardness near to diamond in the tetragonal phase. The large energy gap and low phonon frequencies of the HfO 2 makes it appropriate as a host matrix for been doped with rare earth activators. Efficient luminescent materials find wide application in electroluminescent flat panel displays; color plasma displays panels, scintillators, cathode ray tubes, fluorescent lamps, lasers, etc. In recent years the study of luminescent materials based on HfO 2 has been intensified. Some groups have studied the optical properties of doped and undoped HfO 2 . In this contribution, Hafnium Oxide (HfO 2 ) films were prepared using the spray pyrolysis deposition technique. The material was synthesized using chlorides as raw materials in deionised water as solvent and deposited on Corning glass substrates at temperatures from 300 deg C to 600 deg C. For substrate temperatures lower than 400 deg C, the deposited films are amorphous, while for substrate temperatures higher than 450 deg C, the monoclinic phase of HfO 2 appears. Scanning electron microscopy with microprobe analysis was use to observe the microstructure and obtain the chemical composition of the films; rough surfaces with spherical particles were appreciated. UV and low energy X Ray radiations were used in order to achieve the thermoluminescent characterization of the films as a function of the deposition temperature

  17. 49 CFR 176.133 - Magazine stowage Type C.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Magazine stowage Type C. 176.133 Section 176.133... Requirements for Class 1 (Explosive) Materials Stowage § 176.133 Magazine stowage Type C. The construction requirements for magazine stowage type C are the same as for a closed cargo transport unit in § 176.63(e). In...

  18. 46 CFR 160.176-23 - Marking.

    Science.gov (United States)

    2010-10-01

    ... of the vessel. (2) The type of vessel. (3) Specific purpose or limitation approved by the Coast Guard...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Inflatable Lifejackets § 160.176-23 Marking. (a) General. Each inflatable lifejacket must be marked with the information required by this section. Each marking must be...

  19. Pyroelectricity of silicon-doped hafnium oxide thin films

    Science.gov (United States)

    Jachalke, Sven; Schenk, Tony; Park, Min Hyuk; Schroeder, Uwe; Mikolajick, Thomas; Stöcker, Hartmut; Mehner, Erik; Meyer, Dirk C.

    2018-04-01

    Ferroelectricity in hafnium oxide thin films is known to be induced by various doping elements and in solid-solution with zirconia. While a wealth of studies is focused on their basic ferroelectric properties and memory applications, thorough studies of the related pyroelectric properties and their application potential are only rarely found. This work investigates the impact of Si doping on the phase composition and ferro- as well as pyroelectric properties of thin film capacitors. Dynamic hysteresis measurements and the field-free Sharp-Garn method were used to correlate the reported orthorhombic phase fractions with the remanent polarization and pyroelectric coefficient. Maximum values of 8.21 µC cm-2 and -46.2 µC K-1 m-2 for remanent polarization and pyroelectric coefficient were found for a Si content of 2.0 at%, respectively. Moreover, temperature-dependent measurements reveal nearly constant values for the pyroelectric coefficient and remanent polarization over the temperature range of 0 ° C to 170 ° C , which make the material a promising candidate for IR sensor and energy conversion applications beyond the commonly discussed use in memory applications.

  20. Hafnium oxide nanoparticles: toward an in vitro predictive biological effect?

    International Nuclear Information System (INIS)

    Marill, Julie; Anesary, Naeemunnisa Mohamed; Zhang, Ping; Vivet, Sonia; Borghi, Elsa; Levy, Laurent; Pottier, Agnes

    2014-01-01

    Hafnium oxide, NBTXR3 nanoparticles were designed for high dose energy deposition within cancer cells when exposed to ionizing radiation. The purpose of this study was to assess the possibility of predicting in vitro the biological effect of NBTXR3 nanoparticles when exposed to ionizing radiation. Cellular uptake of NBTXR3 nanoparticles was assessed in a panel of human cancer cell lines (radioresistant and radiosensitive) by transmission electron microscopy. The radioenhancement of NBTXR3 nanoparticles was measured by the clonogenic survival assay. NBTXR3 nanoparticles were taken up by cells in a concentration dependent manner, forming clusters in the cytoplasm. Differential nanoparticle uptake was observed between epithelial and mesenchymal or glioblastoma cell lines. The dose enhancement factor increased with increase NBTXR3 nanoparticle concentration and radiation dose. Beyond a minimum number of clusters per cell, the radioenhancement of NBTXR3 nanoparticles could be estimated from the radiation dose delivered and the radiosensitivity of the cancer cell lines. Our preliminary results suggest a predictable in vitro biological effect of NBTXR3 nanoparticles exposed to ionizing radiation

  1. Studies of high-K isomers in hafnium nuclei

    International Nuclear Information System (INIS)

    Sletten, G.; Gjoerup, N.L.

    1991-01-01

    K-isomeric states built on high-Ω Nilsson orbitals from deformation-aligned high-j levels near the Fermi surface are found to cluster in the neutron rich Hf, W and Os nuclei. It has been shown that some of the high seniority states of this type have decay properties that indicate strong mixing of configurations and that in Osmium nuclei γ-softness cause strong deviations from the well established K-selection rule. Also in the Hafnium nuclei is the expected forbiddenness in isomeric decays an order of magnitude smaller than expected from the K-selection rule. A new 9 quasiparticle isomer has been discovered in 175 Hf at I=57/2. This isomer has the anomalous decay as the dominant mode. Other lower seniority states are also identified. At spin 35/2 and 45/2 the deformation aligned states become yrast, but the structure of the yrast line to even higher spins is not yet understood. (author)

  2. Luminescent determination of zirconium and hafnium with myricetin

    International Nuclear Information System (INIS)

    Talipov, Sh.T.; Zel'tser, L.E.; Morozova, L.A.; Tashkhodzhaev, A.T.

    1978-01-01

    Reaction of formation of 3, 5, 7, 3', 4', 5' - hexaoxiflavone - myricetin complexes with zirconium and hafnium ions has been the basis for development of luminescent method of determining these elements. Optimum conditions for complexing have been determined. For Hf they are : 8-9 HCl concentration, maximum fluorescence wave length (lambda fl.)of 520 nm, wave length of exciting light (lambda el) of 436 nm, for Zr lambda fl = 536nm, lambda el = 436 nm. Stable fluorescence establishes after 25 min. for Zr and after 15 min for Hf in the presence of 40% ethanol. Usage of various camouflage agents has permitted to attain high selectivity of the method. Possibility for determination of Zr with myricetin in the presence of a 10-time excess of Hf, Cr, Cu, 50-time excess of Mo and Ti is shown. Sensitivity of Zr determination is 2.0x10 μg -2 /ml, for Hf it is 9.0x10 μg -3 and mineral waters

  3. Composition and microstructure of zirconium and hafnium germanates obtained by different chemical routes

    International Nuclear Information System (INIS)

    Utkin, A.V.; Prokip, V.E.; Baklanova, N.I.

    2014-01-01

    The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. The products were characterized using high-temperature X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal (TG/DTA) analysis. To investigate the phase composition and stoichiometry of compounds the unit cell parameters were refined by full-profile Rietveld XRD analysis. The morphology of products and its evolution during high-temperature treatment was examined by SEM analysis. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. The ceramic route requires a multi-stage high-temperature treatment to obtain zirconium and hafnium germanates of 95% purity or more. Also, there are strong diffusion limitations to obtain hafnium germanate Hf 3 GeO 8 by ceramic route. On the contrary, the co-precipitation route leads to the formation of nanocrystalline single phase germanates of stoichiometric composition at a relatively low temperatures (less than 1000 °C). The results of quantitative XRD analysis showed the hafnium germanates are stoichiometric compounds in contrast to zirconium germanates that form a set of solid solutions. This distinction may be related to the difference in the ion radii of Zr and Hf. - Graphical abstract: The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. Display Omitted - Highlights: • Zr and Hf germanates were synthesized by ceramic and co-precipitation routes. • The morphology of products depends on the synthesis parameters. • Zirconium germanates forms a set of solid solutions. • Hafnium germanates are stoichiometric compounds

  4. Hafnium isotope ratios of nine GSJ reference samples

    International Nuclear Information System (INIS)

    Hanyu, Takeshi; Nakai, Shun'ichi; Tatsuta, Riichiro

    2005-01-01

    176 Hf/ 177 Hf ratios of nine geochemical reference rocks from the Geological Survey of Japan, together with BIR-1 and BCR-2, were determined using multi-collector inductively coupled plasma mass spectrometry. Our data for BIR-1, BCR-2 and JB-1 are in agreement with those previously reported, demonstrating the appropriateness of the chemical procedure and isotopic measurement employed in this study. The reference rocks have a wide range of 176 Hf/ 177 Hf covering the field defined by various volcanic rocks, such as mid-ocean ridge basalts, ocean island basalts, and subduction related volcanic rocks. They are therefore suitable as rock standards for Hf isotope measurement of geological samples. (author)

  5. 27 CFR 20.176 - Packaging by a dealer.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Packaging by a dealer. 20.176 Section 20.176 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... and Users of Specially Denatured Spirits Operations by Dealers § 20.176 Packaging by a dealer. A...

  6. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component of articles intended for use in producing...

  7. 46 CFR 176.812 - Pressure vessels and boilers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure vessels and boilers. 176.812 Section 176.812... TONS) INSPECTION AND CERTIFICATION Material Inspections § 176.812 Pressure vessels and boilers. (a.... (b) Periodic inspection and testing requirements for boilers are contained in § 61.05 in subchapter F...

  8. 46 CFR 176.655 - Hull examination reports.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Hull examination reports. 176.655 Section 176.655... TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.655 Hull examination reports. (a) If you use only divers for the underwater survey portion of the Alternative Hull Examination (AHE...

  9. 49 CFR 176.130 - Magazine stowage Type A.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Magazine stowage Type A. 176.130 Section 176.130... Requirements for Class 1 (Explosive) Materials Stowage § 176.130 Magazine stowage Type A. (a) In addition to protecting the Class 1 (explosive) materials and preventing unauthorized access, magazine stowage type A...

  10. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176... 100 GROSS TONS) INSPECTION AND CERTIFICATION International Convention for Safety of Life at Sea, 1974, as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than...

  11. 46 CFR 176.675 - Extension of examination intervals.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Extension of examination intervals. 176.675 Section 176... 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.675 Extension of examination intervals. The intervals between drydock examinations and internal structural examinations...

  12. 13 CFR 120.176 - Compliance with other laws.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Compliance with other laws. 120.176 Section 120.176 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Policies Applying to All Business Loans Requirements Imposed Under Other Laws and Orders § 120.176...

  13. 9 CFR 381.176 - Place of maintenance of records.

    Science.gov (United States)

    2010-01-01

    ....176 Section 381.176 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF....176 Place of maintenance of records. Every person engaged in any business described in § 381.175(a) shall maintain the records required by § 381.175 at the place of business where such business is...

  14. 46 CFR 160.176-21 - User manuals.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false User manuals. 160.176-21 Section 160.176-21 Shipping...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Inflatable Lifejackets § 160.176-21 User manuals. (a) The manufacturer must develop a user's manual for each model of inflatable lifejacket. The content of the manual...

  15. 21 CFR 176.350 - Tamarind seed kernel powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tamarind seed kernel powder. 176.350 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a component of articles intended for use in producing...

  16. 49 CFR 176.96 - Materials of construction.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Materials of construction. 176.96 Section 176.96 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Requirements for Barges § 176.96 Materials of construction. Barges used to transport hazardous materials must...

  17. Hafnium Isotopic Variations in Central Atlantic Intraplate Volcanism

    Science.gov (United States)

    Geldmacher, J.; Hanan, B. B.; Hoernle, K.; Blichert-Toft, J.

    2008-12-01

    Although one of the geochemically best investigated volcanic regions on Earth, almost no Hf isotopic data have been published from the broad belt of intraplate seamounts and islands in the East Atlantic between 25° and 36° N. This study presents 176Hf/177Hf ratios from 61 representative samples from the Canary, Selvagen and Madeira Islands and nearby large seamounts, encompassing the full range of different evolutionary stages and geochemical endmembers. The majority of samples have mafic, mainly basaltic compositions with Mg-numbers within or near the range of magmas in equilibrium with mantle olivine (68-75). No correlation was found between Mg-number and 176Hf/177Hf ratios in the data set. In comparison to observed Nd isotope variations published for this volcanic province (6 ɛNd units), 176Hf/177Hf ratios span a larger range (14 ɛHf units). Samples from the Madeira archipelago have the most radiogenic compositions (176Hf/177Hfm= 0.283132-0.283335), widely overlapping the field for central Atlantic N-MORB. They form a relatively narrow, elongated trend (stretching over >6 ɛHf units) between a radiogenic MORB-like endmember and a composition located on the Nd-Hf mantle array. In contrast, all Canary Islands samples plot below the mantle array (176Hf/177Hfm = 0.282943-0.283067) and, despite being from an archipelago that stretches over a much larger geographic area, form a much denser cluster with less compositional variation (~4 ɛHf units). All samples from the seamounts NE of the Canaries, proposed to belong to the same Canary hotspot track (e.g. Geldmacher et al., 2001, JVGR 111; Geldmacher et al., 2005, EPSL 237), fall within the Hf isotopic range of this cluster. The cluster largely overlaps the composition of the proposed common mantle endmember 'C' (Hanan and Graham, 1996, Science 272) but spans a space between a more radiogenic (depleted) composition and a HIMU-type endmember. Although samples of Seine and Unicorn seamounts, attributed to the Madeira

  18. Bond formation in hafnium atom implantation into SiC induced by high-energy electron irradiation

    International Nuclear Information System (INIS)

    Yasuda, H.; Mori, H.; Sakata, T.; Naka, M.; Fujita, H.

    1992-01-01

    Bilayer films of Hf (target atoms)/α-SiC (substrate) were irradiated with 2 MeV electrons in an ultra-high voltage electron microscope (UHVEM), with the electron beam incident on the hafnium layer. As a result of the irradiation, hafnium atoms were implanted into the SiC substrate. Changes in the microstructure and valence electronic states associated with the implantation were studied by a combination of UHVEM and Auger valence electron spectroscopy. The implantation process is summarized as follows. (1) Irradiation with 2 MeV electrons first induces a crystalline-to-amorphous transition in α-SiC. (2) Hafnium atoms which have been knocked-off from the hafnium layer by collision with the 2 MeV electrons are implanted into the resultant amorphous SiC. (3) The implanted hafnium atoms make preferential bonding to carbon atoms. (4) With continued irradiation, the hafnium atoms repeat the displacement along the beam direction and the subsequent bonding with the dangling hybrids of carbon and silicon. The repetition of the displacement and subsequent bonding lead to the deep implantation of hafnium atoms into the SiC substrate. It is concluded that implantation successfully occurs when the bond strength between a constituent atom of a substrate and an injected atom is stronger than that between constituent atoms of a substrate. (Author)

  19. Determination of hafnium, molybdenum, and vanadium in niobium and niobium-based alloys by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Ide, Kunikazu; Kobayashi, Takeshi; Sudo, Emiko.

    1985-01-01

    The analytical procedure is as follows: Weigh 1 g of a sample and put it into a 100 cm 3 PTFE beaker. Add 5 ml of distilled water and 5 ml of hydrofluoric acid, and then heat the solution on a hot plate, adding 3 ml of nitric acid dropwise. Dilute the solution to 100 cm 3 with distilled water. When hafnium is determined, add 2 g of diammonium titanium hexafluoride ((NH 4 ) 2 TiF 6 )) before dilution. Working standard solutions are prepared by adding the stock standard solutions of hafnium, molybdenum, and vanadium into niobium solutions. When hafnium is determined, add 2 g of (NH 4 ) 2 TiF 6 and the alloying elements in amounts corresponding to those in sample solutions into the working standard solutions. The tolerable amounts of hydrofluoric acid were 2.9 M, 2.1 M, and 3.1 M and those of nitric acid were 1.0 M, 1.6 M, and 1.6 M for hafnium, molybdenum, and vanadium, respectively. It was found that (NH 4 ) 2 TiF 6 greatly increased the sensitivity for hafnium determination. Niobium showed minus effect for hafnium and plus effect for molybdenum and vanadium. The atomic absorption of molybdenum and vanadium were not influenced by the presence of 20 % of each alloying element, while the atomic absorption of hafnium was given plus effect by 20 % of zirconium, iron, cobalt, nickel, manganese, chromium or vanadium and minus effect by 20 % tungsten. The analytical values of hafnium, molybdenum, and vanadium in niobium-based alloys by this method showed a good agreement with those by X-ray fluorescence analysis. The lower limits of determination (S/N=2) were 0.05, 0.001, and 0.002 % and the relative standard deviation were 3, 1, and 1.5 % for hafnium, molybdenum, and vanadium, respectively. (author)

  20. Separation of zirconium and hafnium from acompanying elements by paper chromatography in the systems of alcohol-acid

    International Nuclear Information System (INIS)

    Lebedeva, G.G.; Viktorova, M.E.

    1980-01-01

    Solvents have been chosen and investigated which provide expressed separation of zirconium and hafnium at the analysis of mineral raw materials by paper chromatography. The systems with HNO 3 and HCl containing methyl, ethyl, propyl and butyl alcohols have been studied as mobile phases for separation of zirconium and hafnium. It has been shown that alcohol contents and solvent acidity affect the Rsub(f) value of these elements. The C 2 H 5 OH-5MHCl and C 2 H 5 OH-5MHNO 3 systems are most optimal for pre-concentration of zirconium and hafnium

  1. ENTIRELY AQUEOUS SOLUTION-GEL ROUTE FOR THE PREPARATION OF ZIRCONIUM CARBIDE, HAFNIUM CARBIDE AND THEIR TERNARY CARBIDE POWDERS

    Directory of Open Access Journals (Sweden)

    Zhang Changrui

    2016-07-01

    Full Text Available An entirely aqueous solution-gel route has been developed for the synthesis of zirconium carbide, hafnium carbide and their ternary carbide powders. Zirconium oxychloride (ZrOCl₂.8H₂O, malic acid (MA and ethylene glycol (EG were dissolved in water to form the aqueous zirconium carbide precursor. Afterwards, this aqueous precursor was gelled and transformed into zirconium carbide at a relatively low temperature (1200 °C for achieving an intimate mixing of the intermediate products. Hafnium and the ternary carbide powders were also synthesized via the same aqueous route. All the zirconium, hafnium and ternary carbide powders exhibited a particle size of ∼100 nm.

  2. Plasma spraying of zirconium carbide – hafnium carbide – tungsten cermets

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Ctibor, Pavel; Cheong, D.-I.; Yang, S.-H.

    2009-01-01

    Roč. 9, č. 1 (2009), s. 49-64 ISSN 1335-8987 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma spraying * cermet coatings * microhardness * zirconium carbide * hafnium carbide * tungsten * water stabilized plasma Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  3. Titanium, zirconium- and hafnium containing initiators in the polymerization of acrylic monomers to ''living'' polymers

    International Nuclear Information System (INIS)

    Farnham, W.B.; Hertler, W.R.

    1988-01-01

    This patent describes a process for preparing ''living'' polymer. The process comprises contacting one or more acrylic monomers under polymerizing conditions with a polymerization-initiating amount of a tetra-coordinate organotitanium, organozirconium or organo-hafnium polymerization initiator, and ''living'' polymers produced thereby

  4. Vapor pressure, heat capacities, and phase transitions of tetrakis(tert-butoxy)hafnium

    Czech Academy of Sciences Publication Activity Database

    Fulem, Michal; Růžička, K.

    2011-01-01

    Roč. 311, Dec. (2011), s. 25-29 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : tetrakis(tert-butoxy)hafnium * MO precursor * vapor pressure * heat capacity * vaporization enthalpy * enthalpy of fusion Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

  5. Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1981-01-01

    High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 μm) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes 90 Zr and 180 Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer

  6. The corrosion behavior of hafnium in high-temperature-water environments

    Energy Technology Data Exchange (ETDEWEB)

    Rishel, D.M.; Smee, J.D.; Kammenzind, B.F.

    1999-10-01

    The high-temperature-water corrosion performance of hafnium is evaluated. Corrosion kinetic data are used to develop correlations that are a function of time and temperature. The evaluation is based on corrosion tests conducted in out-of-pile autoclaves and in out-of-flux locations of the Advanced Test Reactor (ATR) at temperatures ranging from 288 to 360 C. Similar to the corrosion behavior of unalloyed zirconium, the high-temperature-water corrosion response of hafnium exhibits three corrosion regimes: pretransition, posttransition, and spalling. In the pretransition regime, cubic corrosion kinetics are exhibited, whereas in the posttransition regime, linear corrosion kinetics are exhibited. Because of the scatter in the spalling regime data, it is not reasonable to use a best fit of the data to describe spalling regime corrosion. Data also show that neutron irradiation does not alter the corrosion performance of hafnium. Finally, the data illustrate that the corrosion rate of hafnium is significantly less than that of Zircaloy-2 and Zircaloy-4.

  7. Reinforcement against crack propagation of PWR absorbers by development of boron-carbon-hafnium composites

    International Nuclear Information System (INIS)

    Provot, B.; Herter, P.

    2000-01-01

    In order to improve the mechanical behaviour of materials used as neutron absorbers in nuclear reactors, we have developed CERCER or CERMET composites with boron and hafnium. Thus a new composite B 4 C/HfB 2 has been especially studied. We have identified three kinds of degradation under irradiation (thermal gradient, swelling due to fission products and accidental corrosion) that induce imposed deformations cracking phenomena. Mechanical behaviour and crack propagation resistance have been studied by ball-on-three-balls and double torsion tests. A special device was developed to enable crack propagation and associated stress intensity factor measurements. Effects of structure and of a second phase are underline. First results show that these materials present crack initiation and propagation resistance much higher than pure boron carbide or hafnium diboride. We observe R-Curves effects, crack bridging or branching, crack arrests, and toughness increases that we can relate respectively to the composite structures. (author)

  8. Synthesis and characterization of hafnium oxide films for thermo and photoluminescence applications

    International Nuclear Information System (INIS)

    Guzman Mendoza, J.; Aguilar Frutis, M.A.; Flores, G. Alarcon; Garcia Hipolito, M.; Maciel Cerda, A.; Azorin Nieto, J.; Rivera Montalvo, T.; Falcony, C.

    2010-01-01

    Hafnium oxide (HfO 2 ) films were deposited by the ultrasonic spray pyrolysis process. The films were synthesized from hafnium chloride as raw material in deionized water as solvent and were deposited on corning glass substrates at temperatures from 300 to 600 deg. C. For substrate temperatures lower than 400 deg. C the deposited films were amorphous, while for substrate temperatures higher than 450 deg. C, the monoclinic phase of HfO 2 appeared. Scanning electron microscopy showed that the film's surface resulted rough with semi-spherical promontories. The films showed a chemical composition close to HfO 2 , with an Hf/O ratio of about 0.5. UV radiation was used in order to achieve the thermoluminescent characterization of the films; the 240 nm wavelength induced the best response. In addition, preliminary photoluminescence spectra, as a function of the deposition temperatures, are shown.

  9. Synthesis and characterization of Ho3+ doped hafnium oxide TLD for radiation dosimeter

    International Nuclear Information System (INIS)

    Sekar, Nandakumar; Ganesan, Bharanidharan; Sahib, Hajee Reyaz Ali; Aruna, Prakasarao; Ganesan, Singaravelu; Thamilkumar, P.; Rai, R.R.

    2017-01-01

    Cancer is a dreaded disease which is treated by Radiotherapy, Chemotherapy and Surgery. Radiotherapy plays a vital role in treatment of cancer and recently measurements of invivo radiation dosimetric in patient is of great interest due to high dose gradients in advanced technology like IMRT, IGRT etc. Hence, for the last few decades, a great degree of interest has been shown for the hafnium oxide for radiation dosimetric applications, due to its high dielectric constant, wide band gap and better interface properties such as chemical stability, conduction band offset and thermodynamic stability. In the present study, Synthesis and characterization of Ho 3+ doped Hafnium oxide were carried out and its applications towards radiation dosimeter were investigated

  10. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

    Science.gov (United States)

    Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

    2018-04-12

    Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

  11. Zirconium and hafnium tetrachloride separation by extractive distillation with molten zinc chloride lead chloride solvent

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1988-01-01

    In an extractive distillation method for separating hafniuim tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated into the reflux condenser and through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from the molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement is described comprising: the molten salt having a composition of at least 30 mole percent zinc chloride and at least 10 mole percent of lead chloride

  12. Preparation of hafnium metal by calciothermic reduction of HfO2

    International Nuclear Information System (INIS)

    Sharma, I.G.; Vijay, P.L.; Sehra, J.C.; Sundaram, C.V.

    1975-01-01

    Hafnium metal powder has been produced by the calciothermic reduction of hafnium oxide. The influence of various experimental parameters - such as amount of calcium in excess of stoichiometric requirement, temperature, and time of reduction - on the yield and purity of the metal has been studied. The metal powder obtained by reduction at 960 0 C (two hours) with a calcium excess of 70% analysed 600 ppm of oxygen and 147 ppm of nitrogen. A reduction efficiency of 96% has been achieved under these conditions. The refining of the powder by electron beam melting, fused salt electrolysis, and iodide process has been studied. The oxygen content in the metal could be brought down from 6900 to 148 ppm by electron beam melt-refining. (author)

  13. On-line separation of refractory hafnium and tantalum isotopes at the ISOCELE separator

    CERN Document Server

    Liang, C F; Obert, J; Paris, P; Putaux, J C

    1981-01-01

    By chemical evaporation technique, neutron deficient hafnium nuclei have been on-line separated at the ISOCELE facility, from the isobar rare-earth elements, in the metal-fluoride HfF/sub 3//sup +/ ion form. Half-lives of /sup 162-165/Hf have been measured. Similarly, tantalum has been selectively separated on the TaF/sub 4//sup +/ form. (4 refs) .

  14. Complexonometric determination of hafnium (4) in the presence of europium(3) or tantalum(5)

    International Nuclear Information System (INIS)

    Oziashvili, E.D.; Ehsakiya, K.E.; Sirakanyan, N.M.

    1986-01-01

    Complexonometric determination of hafnium in the presence of Ta or Eu in samples which can be decomposed by acids, i.e. in double borides has been investigated. Initial solutions are prepared by fusing with K 2 S 2 O 8 excess, the fusion was leached by hot water, H 2 SO L 4 was added and Hf was titrated by complexone 3 in the presence of xylenol orange

  15. Simplified method for gravimetric determination of zirconium or hafnium with α-hydroxy carboxylic acids

    International Nuclear Information System (INIS)

    Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Netto, A.

    1989-01-01

    The conditions for gravimetric determination of zirconium or hafnium by glicoloc acids derivatives were studied by thermogravimetric analysis. The method utilized shownd that after precipitation, washing and drying of precipitates at 150 o C, the resulting solid was weighed in the form of [M (RCH(OH)COO) 4 ] (M = Zr, Hf; R + C 6 H 5 , β-C 10 H 7 , p-BrC 6 H 4 ). (author)

  16. Modified method for zirconium or hafnium gravimetric determination with glycolic acid derivatives

    International Nuclear Information System (INIS)

    Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Neto, A.

    1989-01-01

    The conditions for gravimetric determination of zirconium or hafnium by glicolic acid derivatives were studied by thermogravimetric analysis. The method utilized shown that after precipitation, washing and drying of precipitates at 150 0 C, the resulting solid was weighed in the form of [M{RCH(OH)COO} 4 ] (M = Zr,Hf;R = C 6 H 5 , β-C 10 H 7 ,p-BrC 6 H 4 ). (author) [pt

  17. Electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium

    International Nuclear Information System (INIS)

    Serrano, K.

    1998-01-01

    The aim of this work is to study the electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium. The experiment is carried out in a molten alkaline halogenide medium in a temperature range between 670 and 750 degrees Celsius. The first part of this work concerns more particularly the electrochemical behaviour of the hafnium and uranium ions in the electrolytic solution. The reduction mechanisms of these ions have been studied by the use of three methods: cyclic voltametry, chrono-potentiometry and square wave voltametry. Results have shown that the process of metal deposition is difficult to explain because secondary reactions (as for instance: adsorption phenomena or cathodic deposit dissolution) occur. The uranium germination has then been studied by modelling of chrono-amperograms. The experiments have shown that the deposition is the result of the initial uranium crystal growth and depends on the electrolyte diffusion. The second part of this work deals with the implementation of hafnium and uranium deposition taking into account the preceding mechanistic studies. Depositions have all been observed by physical methods as for instance scanning electron microscopy. Particular experimental solutions (soluble anode, addition of fluoride ions to the electrolyte) have been used. The obtained deposition of hafnium is smooth and adheres very well to the substrate. The uranium depositions have been implemented with the use of a soluble anode. Uranium is deposited in a dendritic shape to the cathode. It has also been shown that the electro-kinetic parameters (temperature, uranium ions concentration, current density) have not an important influence on the dendritic morphology of the deposition. This morphology could be the consequence of particular convection movements to the surface of the cathode. (O.M.)

  18. Rhodium and Hafnium Influence on the Microstructure, Phase Composition, and Oxidation Resistance of Aluminide Coatings

    OpenAIRE

    Maryana Zagula-Yavorska; Małgorzata Wierzbińska; Jan Sieniawski

    2017-01-01

    A 0.5 μm thick layer of rhodium was deposited on the CMSX 4 superalloy by the electroplating method. The rhodium-coated superalloy was hafnized and aluminized or only aluminized using the Chemical vapour deposition method. A comparison was made of the microstructure, phase composition, and oxidation resistance of three aluminide coatings: nonmodified (a), rhodium-modified (b), and rhodium- and hafnium-modified (c). All three coatings consisted of two layers: the additive layer and the interdi...

  19. 46 CFR 160.176-4 - Incorporation by reference.

    Science.gov (United States)

    2010-10-01

    .... 751a, Stitches, Seams, and Stitching, January 25, 1965—160.176-9 Military Specifications Naval... Documents, U.S. Government Printing Office, Washington, DC 20402 Special Pub. 440, Color: Universal Language and Dictionary of Names; “The Universal Color Language” and “The Color Names Dictionary”, 1976—160.176...

  20. 21 CFR 169.176 - Concentrated vanilla extract.

    Science.gov (United States)

    2010-04-01

    ... content of ethyl alcohol is not less than 35 percent by volume. (b) The specified name of the food is... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Concentrated vanilla extract. 169.176 Section 169.176 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...

  1. 32 CFR 176.45 - Disposal of buildings and property.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Disposal of buildings and property. 176.45... HOMELESS ASSISTANCE § 176.45 Disposal of buildings and property. (a) Puglic benefit transfer screening. Not... shall dispose of buildings and property in accordance with the record of decision or other decision...

  2. 46 CFR 154.176 - Longitudinal contiguous hull structure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Longitudinal contiguous hull structure. 154.176 Section... Equipment Hull Structure § 154.176 Longitudinal contiguous hull structure. (a) The longitudinal contiguous hull structure of a vessel having cargo containment systems without secondary barriers must meet the...

  3. 21 CFR 176.260 - Pulp from reclaimed fiber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Pulp from reclaimed fiber. 176.260 Section 176.260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: PAPER AND PAPERBOARD COMPONENTS Substances...

  4. 46 CFR 176.700 - Permission for repairs and alterations.

    Science.gov (United States)

    2010-10-01

    ... repair or replacement, other than replacement in kind, of electrical wiring, fuel lines, tanks, boilers... 46 Shipping 7 2010-10-01 2010-10-01 false Permission for repairs and alterations. 176.700 Section... (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Repairs and Alterations § 176.700 Permission for...

  5. 49 CFR 176.160 - Protection against weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Protection against weather. 176.160 Section 176.160 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Protection against weather. Any person loading or unloading packages containing Class 1 (explosive) materials...

  6. 46 CFR 176.635 - Preliminary examination requirements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Preliminary examination requirements. 176.635 Section... (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.635 Preliminary examination requirements. (a) If you exclusively use divers to examine the underwater hull plating, you must...

  7. 49 CFR 176.4 - Port security and safety regulations.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Port security and safety regulations. 176.4... SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY VESSEL General § 176.4 Port security and safety regulations. (a) Each carrier, master, agent, and charterer of a...

  8. Radiation effects on the electrical properties of hafnium oxide based MOS capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Petrosky, J. C. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH); McClory, J. W. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH); Bielejec, Edward Salvador; Foster, J. C. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH)

    2010-10-01

    Hafnium oxide-based MOS capacitors were investigated to determine electrical property response to radiation environments. In situ capacitance versus voltage measurements were analyzed to identify voltage shifting as a result of changes to trapped charge with increasing dose of gamma, neutron, and ion radiation. In situ measurements required investigation and optimization of capacitor fabrication to include dicing, cleaning, metalization, packaging, and wire bonding. A top metal contact of 200 angstroms of titanium followed by 2800 angstroms of gold allowed for repeatable wire bonding and proper electrical response. Gamma and ion irradiations of atomic layer deposited hafnium oxide on silicon devices both resulted in a midgap voltage shift of no more than 0.2 V toward less positive voltages. This shift indicates recombination of radiation induced positive charge with negative trapped charge in the bulk oxide. Silicon ion irradiation caused interface effects in addition to oxide trap effects that resulted in a flatband voltage shift of approximately 0.6 V also toward less positive voltages. Additionally, no bias dependent voltage shifts with gamma irradiation and strong oxide capacitance room temperature annealing after ion irradiation was observed. These characteristics, in addition to the small voltage shifts observed, demonstrate the radiation hardness of hafnium oxide and its applicability for use in space systems.

  9. On the phase formation of sputtered hafnium oxide and oxynitride films

    International Nuclear Information System (INIS)

    Sarakinos, K.; Music, D.; Mraz, S.; Baben, M. to; Jiang, K.; Nahif, F.; Braun, A.; Zilkens, C.; Schneider, J. M.; Konstantinidis, S.; Renaux, F.; Cossement, D.; Munnik, F.

    2010-01-01

    Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar-O 2 -N 2 atmosphere. It is shown that the presence of N 2 allows for the stabilization of the transition zone between the metallic and the compound sputtering mode enabling deposition of films at well defined conditions of target coverage by varying the O 2 partial pressure. Plasma analysis reveals that this experimental strategy facilitates control over the flux of the O - ions which are generated on the oxidized target surface and accelerated by the negative target potential toward the growing film. An arrangement that enables film growth without O - ion bombardment is also implemented. Moreover, stabilization of the transition sputtering zone and control of the O - ion flux without N 2 addition is achieved employing high power pulsed magnetron sputtering. Structural characterization of the deposited films unambiguously proves that the phase formation of hafnium oxide and hafnium oxynitride films with the crystal structure of HfO 2 is independent from the O - bombardment conditions. Experimental and theoretical data indicate that the presence of vacancies and/or the substitution of O by N atoms in the nonmetal sublattice favor the formation of the cubic and/or the tetragonal HfO 2 crystal structure at the expense of the monoclinic HfO 2 one.

  10. Correlations between nuclear data and integral slab experiments: the case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J.M

    1999-07-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  11. Correlations between nuclear data and integral slab experiments: the case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J M

    1999-07-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  12. Correlations between nuclear data and results of integral slab experiments. Case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J M

    1997-10-22

    The aim of this thesis was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular `mock-up` reactor. In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods (APOLLO2 code) together with Monte Carlo- type simulations (TRIPOLI4 code) enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent`s efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author) 128 refs.

  13. Development and characterization of ultrathin hafnium titanates as high permittivity gate insulators

    Science.gov (United States)

    Li, Min

    High permittivity or high-kappa materials are being developed for use as gate insulators for future ultrascaled metal oxide semiconductor field effect transistors (MOSFETs). Hafnium containing compounds are the leading candidates. Due to its moderate permittivity, however, it is difficult to achieve HfO2 gate structures with an EOT well below 1.0 nm. One approach to increase HfO2 permittivity is combining it with a very high-kappa material, such as TiO2. In this thesis, we systematically studied the electrical and physical characteristics of high-kappa hafnium titanates films as gate insulators. A series of HfxTi1-xO2 films with well-controlled composition were deposited using an MOCVD system. The physical properties of the films were analyzed using a variety of characterization techniques. X-ray micro diffraction indicates that the Ti-rich thin film is more immune to crystallization. TEM analysis showed that the thick stoichiometric HfTiO 4 film has an orthorhombic structure and large anisotropic grains. The C-V curves from the devices with the hafnium titanates films displayed relatively low hysteresis. In a certain composition range, the interfacial layer (IL) EOT and permittivity of HfxTi1-x O2 increases linearly with increasing Ti. The charge is negative for HfxTi1-xO2/IL and positive for Si/IL interface, and the magnitude increases as Hf increases. For ultra-thin films (less than 2 nm EOT), the leakage current increases with increasing HE Moreover, the Hf-rich sample has weaker temperature dependence of the current. In the MOSFET devices with the hafnium titanates films, normal transistor characteristics were observed, also electron mobility degradation. Next, we investigated the effects that different pre-deposition surface treatments, including HF dipping, NH3 surface nitridation, and HfO2 deposition, have on the electrical properties of hafnium titanates. Surface nitridation shows stronger effect than the thin HfO2 layer. The nitrided samples displayed a

  14. Low-voltage bendable pentacene thin-film transistor with stainless steel substrate and polystyrene-coated hafnium silicate dielectric.

    Science.gov (United States)

    Yun, Dong-Jin; Lee, Seunghyup; Yong, Kijung; Rhee, Shi-Woo

    2012-04-01

    The hafnium silicate and aluminum oxide high-k dielectrics were deposited on stainless steel substrate using atomic layer deposition process and octadecyltrichlorosilane (OTS) and polystyrene (PS) were treated improve crystallinity of pentacene grown on them. Besides, the effects of the pentacene deposition condition on the morphologies, crystallinities and electrical properties of pentacene were characterized. Therefore, the surface treatment condition on dielectric and pentacene deposition conditions were optimized. The pentacene grown on polystyrene coated high-k dielectric at low deposition rate and temperature (0.2-0.3 Å/s and R.T.) showed the largest grain size (0.8-1.0 μm) and highest crystallinity among pentacenes deposited various deposition conditions, and the pentacene TFT with polystyrene coated high-k dielectric showed excellent device-performance. To decrease threshold voltage of pentacene TFT, the polystyrene-thickness on high-k dielectric was controlled using different concentration of polystyrene solution. As the polystyrene-thickness on hafnium silicate decreases, the dielectric constant of polystyrene/hafnium silicate increases, while the crystallinity of pentacene grown on polystyrene/hafnium silicate did not change. Using low-thickness polystyrene coated hafnium silicate dielectric, the high-performance and low voltage operating (pentacene thin film transistor (μ: ~2 cm(2)/(V s), on/off ratio, >1 × 10(4)) and complementary inverter (DC gains, ~20) could be fabricated.

  15. Extraction of zirconium and hafnium thiocyanates by CH3COCH2CH.(CH3)2-HSCN solvent from chloride medium

    International Nuclear Information System (INIS)

    Okada, A.T.

    1982-01-01

    A zirconium-hafnium separation process for application in nuclear industry is presented. The extraction of zirconium and hafnium thiocyanates in chloride medium by hexone-HSCN solvent was studied. The extraction process was developed, varying the parameters, such as, concentrations of the metals, the thiocyanate ion, the sulphate ion and free acidity in aqueous phase. (Author) [pt

  16. 46 CFR 176.702 - Installation tests and inspections.

    Science.gov (United States)

    2010-10-01

    ..., machinery, fuel tank, or pressure vessel is installed aboard a vessel after completion of the initial... 100 GROSS TONS) INSPECTION AND CERTIFICATION Repairs and Alterations § 176.702 Installation tests and...

  17. Solvent extraction of titanium(IV), zirconium(IV) and hafnium(IV) salicylates using liquid ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthi, N M; Shinde, V M

    1989-02-01

    A solvent extraction method is proposed for the extraction of quadrivalent titanium, zirconium an hafnium from salicylate media using liquid ion exchangers such as Aliquat 336 and trioctylamine dissolved in xylene. The optimum conditions were evaluated from a critical study of the following: pH, salicylate concentration, amine concentration, diluent and period of equilibration. The method allows the separation of titanium, zirconium and hafnium from binary mixtures containing commonly associated metal ions and is applicable to the analysis of real samples such as BCS-CRM 387 nimonic 901, BCS-CRM 243/4 ferro-titanium, BCS-CRM 307 magnesium alloy and BCS-CRM 388 zircon. Titanium is determined either with hydrogen peroxide or by atomic absorption spectrometry whereas zirconium and hafnium are determined spectrophotometrically with Alizarin Red S and Zylenol Orange, respectively. The results of both separation and analysis are reported. The method is precise, accurate and fast.

  18. Use of hafnium in control bars of nuclear reactors; Uso de hafnio en barras de control de reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J.R.; Alonso V, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: jrrs@nuclear.inin-mx

    2003-07-01

    Recently the use of hafnium as neutron absorber material in nuclear reactors has been reason of investigation by virtue of that this material has nuclear properties as to the neutrons absorption and structural that can prolong the useful life of the control mechanisms of the nuclear reactors. In this work some of those more significant hafnium properties are presented like nuclear material. Also there are presented calculations carried out with the HELIOS code for fuel cells of uranium oxide and of uranium and plutonium mixed oxides under controlled conditions with conventional bars of boron carbide and also with similar bars to which are substituted the absorbent material by metallic hafnium, the results are presented in this work. (Author)

  19. Strong influence of polymer architecture on the microstructural evolution of hafnium-alkoxide-modified silazanes upon ceramization.

    Science.gov (United States)

    Papendorf, Benjamin; Nonnenmacher, Katharina; Ionescu, Emanuel; Kleebe, Hans-Joachim; Riedel, Ralf

    2011-04-04

    The present study focuses on the synthesis and ceramization of novel hafnium-alkoxide-modified silazanes as well as on their microstructure evolution at high temperatures. The synthesis of hafnia-modified polymer-derived SiCN ceramic nanocomposites is performed via chemical modification of a polysilazane and of a cyclotrisilazane, followed by cross-linking and pyrolysis in argon atmosphere. Spectroscopic investigation (i.e., NMR, FTIR, and Raman) shows that the hafnium alkoxide reacts with the N-H groups of the cyclotrisilazane; in the case of polysilazane, reactions of N-H as well as Si-H groups with the alkoxide are observed. Consequently, scanning and transmission electron microscopy studies reveal that the ceramic nanocomposites obtained from cyclotrisilazane and polysilazane exhibited markedly different microstructures, which is a result of the different reaction pathways of the hafnium alkoxide with cyclotrisilazane and with polysilazane. Furthermore, the two prepared ceramic nanocomposites are unexpectedly found to exhibit extremely different high-temperature behavior with respect to decomposition and crystallization; this essential difference is found to be related to the different distribution of hafnium throughout the ceramic network in the two samples. Thus, the homogeneous distribution of hafnium observed in the polysilazane-derived ceramic leads to an enhanced thermal stability with respect to decomposition, whereas the local enrichment of hafnium within the matrix of the cyclotrisilazane-based sample induces a pronounced decomposition upon annealing at high temperatures. The results indicate that the chemistry and architecture of the precursor has a crucial effect on the microstructure of the resulting ceramic material and consequently on its high-temperature behavior. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Hafnium at subduction zones: isotopic budget of input and output fluxes; L'hafnium dans les zones de subduction: bilan isotopique des flux entrant et sortant

    Energy Technology Data Exchange (ETDEWEB)

    Marini, J.Ch

    2004-05-15

    Subduction zones are the primary regions of mass exchanges between continental crust and mantle of Earth through sediment subduction toward the earth's mantle and by supply of mantellic magmas to volcanic arcs. We analyze these mass exchanges using Hafnium and Neodymium isotopes. At the Izu-Mariana subduction zone, subducting sediments have Hf and Nd isotopes equivalent to Pacific seawater. Altered oceanic crust has Hf and Nd isotopic compositions equivalent to the isotopic budget of unaltered Pacific oceanic crust. At Luzon and Java subduction zones, arc lavas present Hf isotopic ratios highly radiogenic in comparison to their Nd isotopic ratios. Such compositions of the Luzon and Java arc lavas are controlled by a contamination of their sources by the subducted oceanic sediments. (author)

  1. Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

    International Nuclear Information System (INIS)

    Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku

    2006-01-01

    Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

  2. A study of a production process for hafnium-free zirconium from zircon

    International Nuclear Information System (INIS)

    Ratanalert, N.

    1985-01-01

    The purpose of this experiment was to extract and purify the zirconium from zircon. The effects of time of extraction and stripping of zirconium, concentration of feed solution, concentration of hydrochloric acid in stripping process, equilibrium curve of extraction of zirconium and hafnium and equilibrium curve of stripping zirconium or scrubbing hafnium were studied from standard zirconium and hafnium. The results, subsequently were applied to the extraction procedures for zirconium from zircon. Minus 100 mesh zircon was fused with sodium hydroxide in the ratio of 1 : 6 at 700 degree C for l hour. After fusion the zirconate was leached with water and dissolved in hot concentrated hydrochloric acid. Zirconyl chloride octahydrate crystallized out when the solution was cooled. An agueons solution of zirconyl chloride was used as the feed to the hexone - thiocyanate solvent extraction process. This was prepared by dissolving zirconyl chloride octahydrate crystal in waster. This zirconium feed solution in 1 M HCl and 1 M N H 4 CNS was extracted with 2.7 m N H 4 CNS in hexone and then stripped with 3.6 M HCl the aqueous phase was got rid of thiocyanate ion by extracting with pure hexone, then the zirconium in aqueous phase was precipitated with sulfuric acid and ammonium hydroxide at pH 1.8 - 2.0 and zirconium oxide was obtained by ignition at 700 degree C. The process could be modified to improve the purity of zirconium by using cation exchange resin to get rid of thiocyanate ion after solvent extraction process

  3. Laser coating of hafnium on Ti6Al4 for biomedical applications

    CSIR Research Space (South Africa)

    Phume, L

    2012-12-01

    Full Text Available Al4V FOR BIOMEDICAL APPLICATIONS Lerato Phume 1, 2, S.L. Pityana 1, 2, C. Meacock 1, A.P.I Popoola 2 1. National Laser Centre, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria, 0001, South Africa 2. Department of Chemical... and Metallurgical Engineering, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001, South Africa (b) (c) (e) To investigate laser surface coating of Ti6Al4V with preplaced Hafnium powder, to determine the influence of the energy density...

  4. Improvement of aging kinetics and precipitate size refinement in Mg–Sn alloys by hafnium additions

    Energy Technology Data Exchange (ETDEWEB)

    Behdad, S. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Zhou, L. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Henderson, H.B.; Manuel, M.V. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Sohn, Y. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Agarwal, A. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Boesl, B., E-mail: bboesl@fiu.edu [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

    2016-01-10

    Two Mg–Sn alloys were microalloyed by addition of Hafnium and their age-hardening response was studied at 200 °C. Time to reach peak hardness was significantly reduced and improved by Hf addition. TEM study showed Hf clusters in the close vicinity and at the surface of Mg{sub 2}Sn precipitates, which confirms that Hf clusters act as additional nucleation centers for Mg{sub 2}Sn precipitate formation. Our results support the validity of thermokinetic criterion proposed by Mendis for selection of microalloying elements in order to refine precipitate size, accelerate aging kinetics and enhance peak hardness.

  5. Critical evaluation of the determination of zirconium and hafnium by instrumental and radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Burger, Mario; Kraehenbuehl, Urs

    1991-01-01

    Neutron activation analysis (instrument or radiochemical) is suitable for the determination of zirconium and hafnium in samples of geochemical origin only when sufficient attention is paid to inter-fering nuclides. The size of the necessary correction for INAA depends on the composition of the sample; this problem is discussed. The radio-chemical technique which is recommended involves separation of the samples, precipitations and anion-exchange separation. Results are given for various standard reference materials and for meteorites. (author). 12 refs.; 1 fig.; 9 tabs

  6. High temperature thermodynamics of solutions of oxygen in zirconium and hafnium

    International Nuclear Information System (INIS)

    Boureau, G.; Gerdanian, P.

    1984-01-01

    The Tian-Calvet microcalorimetric method has been applied to the determination at 1323 Kelvin of ΔH(O 2 ), the partial molar enthalpy of mixing of oxygen in zirconium and in hafnium. No measurable departure from Henry's law has been found for dilute solutions (ratio oxygen over metal smaller than 0.1). For concentrated solutions repulsive interactions are found in agreement with the existence of ordered structures at lower temperatures. The domain of homogeneity of zirconium has been found larger than previously assumed. (author)

  7. Complexing of zirconium and hafnium with ortho-aminobenzoic acid and paraaminobenzoic acid

    International Nuclear Information System (INIS)

    Alekseeva, I.I.; Nemzer, I.I.; Yuranova, L.I.; Borisova, V.V.; Prozorovskaya, Z.N.

    1977-01-01

    Formation of complexes between zirconium and hafnium and ortho- and para-aminobenzoic acids has been studied by the kinetic method. It has been found that at pH=1.3-2.0 and concentrations of metals 10 -5 -10 -6 mole complex compounds are formed with composition Me:L=1:2 and 1:1 (Me=Zr, Hf; L=ortho- or para-aminobenzoic acids). Stepwise constants and overall effective constants of complex formation have been calculated

  8. Investigation of interaction of zirconium and hafnium tetrafluorides with strontium fluoride

    International Nuclear Information System (INIS)

    Ratnikova, I.D.; Korenev, Yu.M.; Novoselova, A.V.

    1980-01-01

    Diagrams of the condensated state of systems SrF 2 -EF 4 have been plotted, where E represents Zr, Hf. In these systems, three intermediate compounds of Sr 3 EF 10 , Sr 2 EF 8 and Sr EF 6 compositions are formed. All those compounds melt incongruently at temperatures of 982, 865 and 750 deg C, respectively - zirconium salt; at temperatures of 1000, 900 and 820 deg C - hafnium salts. Fluoro-metallates of composition 2:1, and 1:1, exist in two polymorphic forms. Tetrafluorides were found to dissolve in strontium fluoride: they form solid solutions having fluorite structure

  9. Near net shape processing of zirconium or hafnium metals and alloys

    International Nuclear Information System (INIS)

    Evans, S.C.

    1992-01-01

    This patent describes a process for producing a metal shape. It comprises: plasma arc melting a metal selected from zirconium, hafnium and alloys thereof comprising at least about 90 w/o of these metals to form a liquid pool; pouring the metal form the pool into a mold to form a near net shape; and reducing the metal from its near net shape to a final size while maintaining the metal temperature below the alpha-beta transition temperature throughout the size reducing step

  10. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Cecilia Y. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivas, Patricia [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Universidad Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Pasquevich, Alberto F. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)

    2014-07-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H{sub 2}O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω{sub Q} = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H{sub 2}O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω{sub Q} = 168 Mrad/s. (orig.)

  11. Rare-earth hafnium oxide materials for magnetohydrodynamic (MHD) generator application

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, D. D; Bates, J. L.

    1979-01-01

    Several ceramic materials based on rare-earth hafnium oxides have been identified as potential high-temperature electrodes and low-temperature current leadouts for open cycle coal-fired MHD generator channels. The electrode-current leadouts combination must operate at temperatures between 400 and 2000K with an electrical conductivity greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/. The electrodes will be exposed to flowing (linear flow rates up to 100 m/s) potassium seeded coal combustion gases (plasma core temperatures between 2400 to 3200/sup 0/K) and coal slag. During operation the electrodes must conduct direct electric current at densities near 1.5 amp/cm/sup 2/. Consequently, the electrodes must be resistant to electrochemical decompositions and interactions with both the coal slag and potassium salts (e.g., K/sub 2/SO/sub 4/, K/sub 2/CO/sub 3/). The current leadout materials are placed between the hot electrodes and the water-cooled copper structural members and must have electrical conductivities greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/ between 1400 and 400/sup 0/K. The current leadouts must be thermally and electrochemically compatible with the electrode, copper, and potassium salts. Ideally, the electrodes and current leadouts should exhibit minimal ionic conductivity. The fabrication, electrical conductivity, and electrochemical corrosion of rare-earth hafnium oxide materials are discussed. (WHK)

  12. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Chain, Cecilia Y.; Rivas, Patricia

    2014-01-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H 2 O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω Q = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H 2 O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω Q = 168 Mrad/s. (orig.)

  13. Preparation, structure and properties of hafnium compounds in the system Hf-C-N-O

    International Nuclear Information System (INIS)

    Brundiers, G.D.

    1975-08-01

    Highly dense, homogenous and single phase hafnium carbonitride samples (with low oxygen content) were prepared in the whole concentration range of the ternary cubic carbonitrides. Stoichiometric hafnium oxicarbides were also prepared within the range of solubility. The procedure involved the hot pressing of powders of HfC, HfN, Hf, Hf-Oxide and carbon at temperatures of 3,000 0 C and pressures up to 550 kpf/cm 2 using a novel technique. Small single crystals of slightly substoichiometric HfN were also repared. The densification of the powders was studied as a function of the non-metal concentration. Carbonitrides with N/Hf ratio of 0.37 were prepared in a high temperature autoclave operating at medium pressures by the reaction of HfC with nitrogen. All the samples were characterized by density measurements, chemical, X-ray and metallographic analysis and in some cases with the aid of quantitative metallography and microprobe analysis. Typical properties investigated were lattice parameter, thermal expansion, microhardness and electrical resistivity as function of the non-metal content. For specific concentrations extreme values in the properties are attained. With the aid of the valence electron concentration (VEC) parameter, the properties can be correlated with the density of states of electrons at the Fermi level. (orig./HK) [de

  14. Titrimetric determination of thiocyanate in solutions of the hafnium-zirconium separation process

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Botbol, Moises; Hernandez, M.H.

    1980-01-01

    The control of the thiocyanate concentration is necessary during the process of separating hafnium from zirconium by the hexone-thiocyanate method. Said control is carried out by titrimetric determination of thiocyanate in aqueous and organic solutions containing hydrochloric acid and ammonium thiocyanate in presence or absence of zirconium and/or hafnium. The method consists in a redox volumetric analysis using a cerium (IV) salt as titrating agent, and ferroine as the final point indicator. Owing to the instability of thiocyanate in an acid medium it is necessary to know previously if the decomposition of solutions with different concentration of ammonium thiocyanate and hydrochloric acid may have an influence upon the analytic results or may even invalidate them. In order to obtain reliable results, it must be taken into account that the stability of the solutions depends on the thiocyanate concentration, the acidity and the time elapsed from the moment the sample is taken until the test is performed. The decomposition process can be slowed down by cooling the solutions. This method allows to control the plant and does not require any special equipment. (M.E.L) [es

  15. Molecular structure, vibrational, HOMO-LUMO, MEP and NBO analysis of hafnium selenite

    Science.gov (United States)

    Yankova, Rumyana; Genieva, Svetlana; Dimitrova, Ginka

    2017-08-01

    In hydrothermal condition hafnium selenite with estimated chemical composition Hf(SeO3)2·n(H2O) was obtained and characterized by powder X-Ray diffraction, IR spectroscopy and thermogravimetrical analysis. The composition of the obtained crystalline phase was established as dihydrate of tetraaqua complex of the hafnium selenite [Hf(SeO3)2(H2O)4]·2H2O. The results of the thermogravimetrical analysis are shown that the two hydrated water molecules are released in the temperature interval 80-110°C, while the four coordinated water molecules - at 210-300°C. By DFT method, with Becke's three parameter exchange-functional combined with gradient-corrected correlation functional of Lee, Yang and Parr and 6-31G(d), 6-311 + G(d,p) basis sets and LANL2DZ for Hf atom were calculated the molecular structure, vibrational frequencies and thermodynamic properties of the structure. The UV-Vis spectra and electronic properties are presented. The energy and oscillator strength calculated by time-dependent density functional theory corresponds well with the experimental ones. Molecular electrostatic potential (MEP) was performed. Mulliken population analysis on atomic charges was also calculated. The stability and intramolecular interactions are interpreted by NBO analysis.

  16. Correlations between nuclear data and results of integral slab experiments. Case of hafnium

    International Nuclear Information System (INIS)

    Palau, J.M.

    1997-01-01

    The aim of this thesis was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor. In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods (APOLLO2 code) together with Monte Carlo- type simulations (TRIPOLI4 code) enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope 177 Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  17. Correlations between nuclear data and integral slab experiments: the case of hafnium

    International Nuclear Information System (INIS)

    Palau, J.M.

    1999-01-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope 177 Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  18. Highly substituted zirconium and hafnium cyclopentadienyl bifunctional β-diketiminate complexes – Synthesis, structure, and catalytic activity towards ethylene polymerization

    Czech Academy of Sciences Publication Activity Database

    Havlík, A.; Lamač, Martin; Pinkas, Jiří; Varga, Vojtěch; Růžička, A.; Olejník, R.; Horáček, Michal

    2015-01-01

    Roč. 786, JUN 2015 (2015), s. 71-80 ISSN 0022-328X R&D Projects: GA ČR GAP106/10/0924 Institutional support: RVO:61388955 Keywords : Zirconium * Hafnium * Cyclopentadienyl Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.336, year: 2015

  19. Differential perturbed angular correlation: use of physico-chemical study of some hafnium complexes derivates of hydroxy acids and EDTA

    International Nuclear Information System (INIS)

    Silveira, J.G. da.

    1981-01-01

    Measures of quadrupolar interaction to nucleus level of the metal, in some hafnium complexes are presented, including the analysis by combustion, microanalysis, infrared spectroscopy and thermogravimetry. The hyperfine interaction parameters, the temperature effects and the thermal neutrons capture effects over the irradiated Hf Y (Y = EDTA) are also studied. (author)

  20. 27 CFR 24.176 - Crushing and fermentation.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Crushing and fermentation..., DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.176 Crushing and fermentation. (a) Natural... fermentation but the density of the juice may not be reduced below 22 degrees Brix. However, if the juice is...

  1. 46 CFR 199.176 - Markings on lifesaving appliances.

    Science.gov (United States)

    2010-10-01

    ... ARRANGEMENTS LIFESAVING SYSTEMS FOR CERTAIN INSPECTED VESSELS Requirements for All Vessels § 199.176 Markings on lifesaving appliances. (a) Lifeboats and rescue boats. Each lifeboat and rescue boat must be plainly marked as follows: (1) Each side of each lifeboat and rescue boat bow must be marked in block...

  2. Experimental half-life determination of 176Lu

    International Nuclear Information System (INIS)

    Kossert, Karsten; Jörg, Gerhard; Gostomski, Christoph Lierse v.

    2013-01-01

    The half-life of the naturally occurring long-lived rare earth isotope 176 Lu was determined by a combination of highly sophisticated experimental procedures in order to further improve the reliability and the precision of literature data. The amount of lutetium in the samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using a NIST reference standard. The isotopic ratio N( 176 Lu)/N(Lu) in the samples was measured by means of inductively coupled plasma high resolution mass spectrometry (ICP-HRMS). The activity divided by the mass of Lu was determined by applying liquid scintillation (LS) counting. The LS counting efficiency of the beta/gamma emitter 176 Lu was determined with the CIEMAT/NIST efficiency tracing technique with low uncertainty. The influences of colour quenching and background effects are discussed in this paper. The half-life was found to be 3.640(35)×10 10 y. The result is in good agreement with other evaluations and the relative standard uncertainty of 0.95% is among the lowest of previously published data. - Highlights: • The half-life of 176 Lu was determined by ICP-OES, ICP-HRMS and LSC. • The LSC efficiency was determined with the CIEMAT/NIST method. • The half-life was found to be 3.640(35)×10 10 y

  3. 46 CFR 176.816 - Miscellaneous systems and equipment.

    Science.gov (United States)

    2010-10-01

    ... 100 GROSS TONS) INSPECTION AND CERTIFICATION Material Inspections § 176.816 Miscellaneous systems and equipment. At each initial and subsequent inspection for certification the owner or managing operator shall be prepared to test and make available for inspection all items in the ship's outfit, such as ground...

  4. 28 CFR 35.176 - Alternative means of dispute resolution.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Alternative means of dispute resolution... DISABILITY IN STATE AND LOCAL GOVERNMENT SERVICES Compliance Procedures § 35.176 Alternative means of dispute resolution. Where appropriate and to the extent authorized by law, the use of alternative means of dispute...

  5. A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

    Directory of Open Access Journals (Sweden)

    S. Riedel

    2016-09-01

    Full Text Available Ferroelectric properties in hafnium oxide based thin films have recovered the scaling potential for ferroelectric memories due to their ultra-thin-film- and CMOS-compatibility. However, the variety of physical phenomena connected to ferroelectricity allows a wider range of applications for these materials than ferroelectric memory. Especially mixed HfxZr1-xO2 thin films exhibit a broad compositional range of ferroelectric phase stability and provide the possibility to tailor material properties for multiple applications. Here it is shown that the limited thermal stability and thick-film capability of HfxZr1-xO2 can be overcome by a laminated approach using alumina interlayers.

  6. Surface State Capture Cross-Section at the Interface between Silicon and Hafnium Oxide

    Directory of Open Access Journals (Sweden)

    Fu-Chien Chiu

    2013-01-01

    Full Text Available The interfacial properties between silicon and hafnium oxide (HfO2 are explored by the gated-diode method and the subthreshold measurement. The density of interface-trapped charges, the current induced by surface defect centers, the surface recombination velocity, and the surface state capture cross-section are obtained in this work. Among the interfacial properties, the surface state capture cross-section is approximately constant even if the postdeposition annealing condition is changed. This effective capture cross-section of surface states is about 2.4 × 10−15 cm2, which may be an inherent nature in the HfO2/Si interface.

  7. Thermal expansion studies on Hafnium titanate (HfTiO4)

    International Nuclear Information System (INIS)

    Panneerselvam, G.; Subramanian, G.G.S.; Antony, M.P.

    2006-01-01

    The lattice thermal expansion characteristics of hafnium titanate (HfTiO 4 ) have been studied by measuring the lattice parameter as a function of temperature by high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1973K. Percentage linear thermal expansion and mean linear thermal expansion coefficients were computed from the lattice parameter data. The thermal expansion of HfTiO 4 is highly anisotropic. The expansivity along 'a' axis is large; as compared to the expansivity along 'b' axis which is negative below 1073 K. The percentage linear thermal expansion in the temperature range 298-1973 K along a, b and c axis are 2.74, 0.901 and 1.49 respectively. Thermal expansion values obtained in the present study are in reasonable agreement with the existing thermal expansion data. (author)

  8. Density and surface tension of melts of zirconium and hafnium fluorides with lithium fluoride

    International Nuclear Information System (INIS)

    Katyshev, S.F.; Artemov, V.V.; Desyatnik, V.N.

    1988-01-01

    A study was conducted to determine the temperature dependence of the density and surface tension of melts of LiF-ZrF 4 and LiF-HfF 4 . Density and surface tension were determined by the method of maximum pressure in an argon bubble. On the basis of experimental data over the entire concentration range the molar volumes and their relative deviations from the additive molar volumes were calculated for 1100 0 K. The positive deviations of the molar volumes from additivity in the LiF-HfF 4 system (22.45%) were greater than in the LiF-ZrF 4 system (15.75%). This indicated that the reaction with lithium fluoride is intensified with the switch to the hafnium fluoride. Results also demonstrated that the fluorides are surface-active components in the molten mixtures

  9. Extraction of hafnium with chelating agents from aqueous-alcoholic solutions

    International Nuclear Information System (INIS)

    Hala, J.; Prihoda, J.

    1975-01-01

    The extraction was studied of hafnium into solutions of N-benzoyl-N-phenylhydroxylamine, 2-thenoyltrifluoroacetone and di-n-butylphosphoric acid in benzene, toluene, chloroform and tetrachloromethane from aqueous alcoholic solutions with a formal acidity of 2M-HClO 4 . Methyl-, ethyl-, n- and isopropyl- and tert-butyl alcohol were used as organic components in the mixed aqueous-organic phase. In the extraction into N-benzoyl-N-phenylhydroxylamine the presence of the alcohols resulted in synergic effects analogous to the previously described extraction by substituted benzoylpyrazolone. With the other two extractants, the effect of the alcohols was antagonistic, due to the interaction of alcohol or water with the reagent in the organic phase, and to the decrease in the reagent distribution constant. (author)

  10. Interface and oxide traps in high-κ hafnium oxide films

    International Nuclear Information System (INIS)

    Wong, H.; Zhan, N.; Ng, K.L.; Poon, M.C.; Kok, C.W.

    2004-01-01

    The origins of the interface trap generation and the effects of thermal annealing on the interface and bulk trap distributions are studied in detail. We found that oxidation of the HfO 2 /Si interface, removal of deep trap centers, and crystallization of the as-deposited film will take place during the post-deposition annealing (PDA). These processes will result in the removal of interface traps and deep oxide traps and introduce a large amount of shallow oxide traps at the grain boundaries of the polycrystalline film. Thus, trade-off has to be made in considering the interface trap density and oxide trap density when conducting PDA. In addition, the high interface trap and oxide trap densities of the HfO 2 films suggest that we may have to use the SiO 2 /HfO 2 stack or hafnium silicate structure for better device performance

  11. Wake-up effects in Si-doped hafnium oxide ferroelectric thin films

    International Nuclear Information System (INIS)

    Zhou, Dayu; Xu, Jin; Li, Qing; Guan, Yan; Cao, Fei; Dong, Xianlin; Müller, Johannes; Schenk, Tony; Schröder, Uwe

    2013-01-01

    Hafnium oxide based ferroelectric thin films have shown potential as a promising alternative material for non-volatile memory applications. This work reports the switching stability of a Si-doped HfO 2 film under bipolar pulsed-field operation. High field cycling causes a “wake-up” in virgin “pinched” polarization hysteresis loops, demonstrated by an enhancement in remanent polarization and a shift of negative coercive voltage. The rate of wake-up is accelerated by either reducing the frequency or increasing the amplitude of the cycling field. We suggest de-pinning of domains due to reduction of the defect concentration at bottom electrode interface as origin of the wake-up

  12. Atom-vacancy ordering and magnetic susceptibility of nonstoichiometric hafnium carbide

    International Nuclear Information System (INIS)

    Gusev, A.I.; Zyryanova, A.N.

    1999-01-01

    Experimental results on magnetic susceptibility of nonstoichiometric hafnium carbide HfC y (0.6 0.71 , HfC 0.78 and HfC 0.83 in the range of 870-930 K the anomalies are revealed which are associated with superstructure short-range ordering in a non-metallics sublattice. It is shown that a short-range order in HfC 0.71 and HfC 0.78 carbides corresponds to Hf 3 C 2 ordered phase, and in HfC 0.83 carbide - to Hf 6 C 5 ordered phase. HfC 0.78 carbide is found to possesses zero magnetic susceptibility in temperature range 910-980 K [ru

  13. Sub-10 nm low current resistive switching behavior in hafnium oxide stack

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Y., E-mail: houyi@pku.edu.cn, E-mail: lfliu@pku.edu.cn [Institute of Microelectronics, Peking University, 100871 Beijing (China); IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Celano, U.; Xu, Z.; Vandervorst, W. [IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Goux, L.; Fantini, A.; Degraeve, R.; Youssef, A.; Jurczak, M. [IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Liu, L., E-mail: houyi@pku.edu.cn, E-mail: lfliu@pku.edu.cn; Cheng, Y.; Kang, J. [Institute of Microelectronics, Peking University, 100871 Beijing (China)

    2016-03-21

    In this letter, a tip-induced cell relying on the conductive atomic force microscope is proposed. It is verified as a referable replica of an integrated resistive random access memory (RRAM) device. On the basis of this cell, the functionality of sub-10 nm resistive switching is confirmed in hafnium oxide stack. Moreover, the low current switching behavior in the sub-10 nm dimension is found to be more pronounced than that of a 50 × 50 nm{sup 2} device. It shows better ON/OFF ratio and low leakage current. The enhanced memory performance is ascribed to a change in the shape of the conductive filament as the device dimensions are reduced to sub-10 nm. Therefore, device downscaling provides a promising approach for the resistance optimization that benefits the RRAM array design.

  14. Solvent extraction of hafnium(IV) by dinonylnaphthalene sulfonic acid from mixed aqueous-organic media

    International Nuclear Information System (INIS)

    Hala, J.; Piperkovova, H.

    1979-01-01

    The extraction of hafnium(IV) by heptane and toluene solutions of dinonylnaphthalene sulfonic acid (HD) from mixed aqueous-organic solutions has been studied. Alcohols, ketones, carboxylic acids, cyclic ethers, dimethylsulfoxide and dimethylformamide were used as the organic component of the mixed phase. Methanol, ethanol, formic acid and dioxane increased the extractability of Hf(IV) whereas other solvents showed only an antagonistic effect. The results were discussed from the point of view of the changes in micellar structure of HD, and compared with the uptake of Hf(IV) by resinous cation exchangers. The solubilization by HD of alcohols, carboxylic acids and dimethylsulfoxide was demonstrated by using the corresponding 14 C and 35 S labelled compounds. (author)

  15. Study of bulk Hafnium oxide (HfO2) under compression

    Science.gov (United States)

    Pathak, Santanu; Mandal, Guruprasad; Das, Parnika

    2018-04-01

    Hafnium oxide (HfO2) is a technologically important material. This material has K-value of 25 and band gap 5.8 eV. A k value of 25-30 is preferred for a gate dielectric [1]. As it shows good insulating and capacitive properties, HfO2 is being considered as a replacement to SiO2 in microelectronic devices as gate dielectrics. On the other hand because of toughening mechanism due to phase transformation induced by stress field observed in these oxides, HFO2 has been a material of investigations in various configurations for a very long time. However the controversies about phase transition of HfO2 under pressure still exists. High quality synchrotron radiation has been used to study the structural phase transition of HfO2 under pressure.

  16. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Salyulev, A B; Kudyakov, V Ya; Smirnov, M V; Moskalenko, N I [AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii

    1984-08-01

    The coefficient of HfCl/sub 4/ and ZrCl/sub 4/ separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl/sub 4/+HfCl/sub 4/). HfCl/sub 4/ and ZrCl/sub 4/ are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl.

  17. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    International Nuclear Information System (INIS)

    Salyulev, A.B.; Kudyakov, V.Ya.; Smirnov, M.V.; Moskalenko, N.I.

    1984-01-01

    The coefficient of HfCl 4 and ZrCl 4 separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl 4 +HfCl 4 ). HfCl 4 and ZrCl 4 are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl

  18. Influence of plastic deformation on nitriding of a molybdenum-hafnium alloy

    International Nuclear Information System (INIS)

    Lakhtin, Yu.M.; Kogan, Ya.D.; Shashkov, D.P.; Likhacheva, T.E.

    1982-01-01

    The influence of a preliminary plastic strain on the structure and properties of molybdenum alloy with 0.2 wt.% Hf upon nitriding in the ammonia medium at 900-1200 deg C during 1-6 h is investigated. The study of microhardness distribution across the nitrided layer thickness has shown that with increase of the degree of preliminary plastic strain up to 50 % the nitrided layer hardness decreases and with further reduction growth up to 90 % - increases. Nitriding sharply (hundred times) increases wear resistance of molybdenum alloy with hafnium addition. At the reduction degree 25 % the wear resistance is less than at other values of percentage reduction in area owing to the minimum thickness of the nitride zone. The alloy strained before nitriding by 25 % has shown the best results during heat resistance testing

  19. Hafnium at subduction zones: isotopic budget of input and output fluxes

    International Nuclear Information System (INIS)

    Marini, J.Ch.

    2004-05-01

    Subduction zones are the primary regions of mass exchanges between continental crust and mantle of Earth through sediment subduction toward the earth's mantle and by supply of mantellic magmas to volcanic arcs. We analyze these mass exchanges using Hafnium and Neodymium isotopes. At the Izu-Mariana subduction zone, subducting sediments have Hf and Nd isotopes equivalent to Pacific seawater. Altered oceanic crust has Hf and Nd isotopic compositions equivalent to the isotopic budget of unaltered Pacific oceanic crust. At Luzon and Java subduction zones, arc lavas present Hf isotopic ratios highly radiogenic in comparison to their Nd isotopic ratios. Such compositions of the Luzon and Java arc lavas are controlled by a contamination of their sources by the subducted oceanic sediments. (author)

  20. Rapid screening of nuclear grade zirconium silicate without separation of hafnium from the bulk matrix

    International Nuclear Information System (INIS)

    Venkatesh, Manisha; Sharma, P.K.; Avhad, D.K.; Basu, H.; Singhal, R.K.; Reddy, A.V.R.

    2014-01-01

    Zirconium silicate, also zirconium orthosilicate, (ZrSiO 4 ) is a chemical compound, and occurs in nature as zircon, a silicate mineral. The concentration of Hafnium in nuclear grade Zirconium must be less than 0.2% w/w of Zr. In view of this it must be accurately chemically characterized before issuing a certification for export under non nuclear category. As the chemistry of Zr and Hf is similar, it is difficult to separate Hf by direct wet chemical method. During this work, concentration of Hf in zirconium silicate was measured by Field Portable X-ray Fluorescence (FPXRF) and results obtained were validated by using detailed chemical method. FPXRF spectrometry has become a common analytical technique for on-site screening and fast turnaround analysis of contaminant elements in environmental samples

  1. Gemini spectroscopy of the outer disk star cluster BH176

    Science.gov (United States)

    Sharina, M. E.; Donzelli, C. J.; Davoust, E.; Shimansky, V. V.; Charbonnel, C.

    2014-10-01

    Context. BH176 is an old metal-rich star cluster. It is spatially and kinematically consistent with belonging to the Monoceros Ring. It is larger in size and more distant from the Galactic plane than typical open clusters, and it does not belong to the Galactic bulge. Aims: Our aim is to determine the origin of this unique object by accurately determining its distance, metallicity, and age. The best way to reach this goal is to combine spectroscopic and photometric methods. Methods: We present medium-resolution observations of red clump and red giant branch stars in BH176 obtained with the Gemini South Multi-Object Spectrograph. We derive radial velocities, metallicities, effective temperatures, and surface gravities of the observed stars and use these parameters to distinguish member stars from field objects. Results: We determine the following parameters for BH176: Vh = 0 ± 15 km s-1, [Fe/H] = -0.1 ± 0.1, age 7 ± 0.5 Gyr, E(V - I) = 0.79 ± 0.03, distance 15.2 ± 0.2 kpc, α-element abundance [α/Fe] ~ 0.25 dex (the mean of [Mg/Fe], and [Ca/Fe]). Conclusions: BH176 is a member of old Galactic open clusters that presumably belong to the thick disk. It may have originated as a massive star cluster after the encounter of the forming thin disk with a high-velocity gas cloud or as a satellite dwarf galaxy. Appendix A is available in electronic form at http://www.aanda.org

  2. Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyralozone from aqueous-alcoholic solutions

    International Nuclear Information System (INIS)

    Hala, J.; Prihoda, J.

    1975-01-01

    Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO 4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL 4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in the organic phase. (author)

  3. Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago.

    Science.gov (United States)

    Næraa, T; Scherstén, A; Rosing, M T; Kemp, A I S; Hoffmann, J E; Kokfelt, T F; Whitehouse, M J

    2012-05-30

    Earth's lithosphere probably experienced an evolution towards the modern plate tectonic regime, owing to secular changes in mantle temperature. Radiogenic isotope variations are interpreted as evidence for the declining rates of continental crustal growth over time, with some estimates suggesting that over 70% of the present continental crustal reservoir was extracted by the end of the Archaean eon. Patterns of crustal growth and reworking in rocks younger than three billion years (Gyr) are thought to reflect the assembly and break-up of supercontinents by Wilson cycle processes and mark an important change in lithosphere dynamics. In southern West Greenland numerous studies have, however, argued for subduction settings and crust growth by arc accretion back to 3.8 Gyr ago, suggesting that modern-day tectonic regimes operated during the formation of the earliest crustal rock record. Here we report in situ uranium-lead, hafnium and oxygen isotope data from zircons of basement rocks in southern West Greenland across the critical time period during which modern-like tectonic regimes could have initiated. Our data show pronounced differences in the hafnium isotope-time patterns across this interval, requiring changes in the characteristics of the magmatic protolith. The observations suggest that 3.9-3.5-Gyr-old rocks differentiated from a >3.9-Gyr-old source reservoir with a chondritic to slightly depleted hafnium isotope composition. In contrast, rocks formed after 3.2 Gyr ago register the first additions of juvenile depleted material (that is, new mantle-derived crust) since 3.9 Gyr ago, and are characterized by striking shifts in hafnium isotope ratios similar to those shown by Phanerozoic subduction-related orogens. These data suggest a transitional period 3.5-3.2 Gyr ago from an ancient (3.9-3.5 Gyr old) crustal evolutionary regime unlike that of modern plate tectonics to a geodynamic setting after 3.2 Gyr ago that involved juvenile crust generation by plate

  4. Results for heterogeneous poisoning of the critical HTR-test facility KAHTER using absorber elements containing hafnium and boron

    International Nuclear Information System (INIS)

    Drueke, V.; Filges, D.; Nabi, R.; Neef, R.D.; Paul, N.; Schaal, H.

    1979-10-01

    Experiments and checking computations for investigating the initial-core poisoning of the pebble bed high temperature reactor are described. Following the example of the THTR-300, THTR absorber elements poisoned with hafnium/boron were added to the THTR fuel- and graphite elements of the KAHTER core. Three different hafnium-boron poisoned core loadings, corresponding to 2.7, 5.3 and 8% reactivity compensation, were used in the experiments. For purposes of comparison, two cores exclusively boron poisoned were also studied. The poisoning of these cores correspond to 2.7 and 8% reactivity compensation. The experiments and checking computations should serve to test the accuracy of the theoretical models and data sets in modeling the reactivity effects of absorber poisoned elements in the THTR. In particular, the applicability of the nuclear data of hafnium and the treatment of resonance calculations should be verified. In addition, to determining critical masses and ksub(eff), special emphasis was placed in the experiments on the exact determination of all reactivity effects. In some cases, repeated loading of a configuration also provided a measure of the reproducibility of ksub(eff). The experiments were checked computationally using the GAMTEREX code package and the program system RSYST. These two computation packages contain different data bases, - although the hafnium data are identical -, and the computing models differ in certain phases of the calculations. Both code systems compute ksub(eff) values to within the present accuracy requirements, whereas the program system RSYST gives better agreement with experimental measurements. (orig.) 891 RW/orig. 892 RDG [de

  5. Ion-bombardment-induced reduction in vacancies and its enhanced effect on conductivity and reflectivity in hafnium nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhiqing; Wang, Jiafu; Hu, Chaoquan; Zhang, Xiaobo; Dang, Jianchen; Gao, Jing; Zheng, Weitao [Jilin University, School of Materials Science and Engineering, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Changchun (China); Zhang, Sam [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Xiaoyi [Chinese Academy of Sciences, Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun (China); Chen, Hong [Jilin University, Department of Control Science and Engineering, Changchun (China)

    2016-08-15

    Although the role of ion bombardment on electrical conductivity and optical reflectivity of transition metal nitrides films was reported previously, the results were controversial and the mechanism was not yet well explored. Here, we show that proper ion bombardment, induced by applying the negative bias voltage (V{sub b}), significantly improves the electrical conductivity and optical reflectivity in rocksalt hafnium nitride films regardless of level of stoichiometry (i.e., in both near-stoichiometric HfN{sub 1.04} and over-stoichiometric HfN{sub 1.17} films). The observed improvement arises from the increase in the concentration of free electrons and the relaxation time as a result of reduction in nitrogen and hafnium vacancies in the films. Furthermore, HfN{sub 1.17} films have always much lower electrical conductivity and infrared reflectance than HfN{sub 1.04} films for a given V{sub b}, owing to more hafnium vacancies because of larger composition deviation from HfN exact stoichiometry (N:Hf = 1:1). These new insights are supported by good agreement between experimental results and theoretical calculations. (orig.)

  6. Early history of Earth's crust-mantle system inferred from hafnium isotopes in chondrites

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Haack, Henning; Rosing, M.

    2003-01-01

    for the chondrite-forming event. This ¿176 value indicates that Earth's oldest minerals were derived from melts of a mantle source with a time-integrated history of depletion rather than enrichment. The depletion event must have occurred no later than 320 Myr after planetary accretion, consistent with timing......The Lu to Hf decay series has been widely used to understand the nature of Earth's early crust-mantle system. The interpretation, however, of Lu-Hf isotope data requires accurate knowledge of the radioactive decay constant of Lu (¿176), as well as bulk-Earth reference parameters. A recent...

  7. 49 CFR 176.99 - Permit requirements for certain hazardous materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Permit requirements for certain hazardous materials. 176.99 Section 176.99 Transportation Other Regulations Relating to Transportation PIPELINE AND... CARRIAGE BY VESSEL Special Requirements for Barges § 176.99 Permit requirements for certain hazardous...

  8. 49 CFR 176.194 - Stowage of Class 1 (explosive) materials on magazine vessels.

    Science.gov (United States)

    2010-10-01

    ... magazine vessels. 176.194 Section 176.194 Transportation Other Regulations Relating to Transportation... REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Magazine Vessels § 176.194 Stowage of Class 1 (explosive) materials on magazine vessels. (a) General. The requirements of...

  9. 40 CFR 81.176 - San Luis Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false San Luis Intrastate Air Quality Control Region. 81.176 Section 81.176 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.176 San Luis Intrastate Air Quality Control Region. The San Luis Intrastate...

  10. Nano-scale Radiotherapy-NBTXR3 Hafnium Oxide Nanoparticles as Promising Cancer Therapy

    International Nuclear Information System (INIS)

    Maggiorella, L.; Barouch, G.; Devaux, C.; Pottier, A.; Levy, L.; Deutsch, E.; Bourhis, J.; Borghi, E.

    2011-01-01

    Complete text of publication follows: Background: There is considerable interest in approaches that could improve the therapeutic window of radiotherapy, which represents a crucial modality of treatment in oncology. We present the rationale for designing NBTXR3 nanoparticles activated by radiotherapy and validate the concept. We performed the Monte Carlo calculations for the first time based on the 'local model' simulation that showed a dose enhancement of radiation to tumour cells of approximately nine-fold. NBTXR3 was shown to deposit high energy when the ionizing radiation source is 'on' and to have chemically inert behavior in cellular and subcellular systems demonstrated by very good systemic tolerance, thus decreasing potential health hazards. Material and Methods: We used conventional methods, implemented in different ways, to explore interactions of high Z matter and ionizing radiation with biological systems. In addition, microtomography was performed to explore the nanoparticle volume occupancy inside the tumour and its persistence overtime in mouse tumour models. The antitumour activity of NBTXR3 and tolerance were evaluated in Ewing tumour (A673) and fibrosarcoma (HT1080) using high energy source. Results and Conclusion: We created and developed NBTXR3 nanoparticles with a crystalline hafnium oxide core which provide high electron density structure and inert behavior in biological media. NBTXR3 nanoparticles' characteristics, size, charge and shape, allow for efficient interaction with biological entities, cell membrane binding and cellular uptake. The nanoparticles were shown to form clusters at the subcellular level in tumour models. Of most importance, we show NBTXR3 intra-tumour bioavailability with dispersion of nanoparticles in the three dimensions and persistence within the tumour structure, supporting the use of NBTXR3 as effective antitumour therapeutic agent. Antitumour activity of NBTXR3 showed marked advantage in terms of survival, tumour

  11. Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment.

    Science.gov (United States)

    Chen, Min-Hua; Hanagata, Nobutaka; Ikoma, Toshiyuki; Huang, Jian-Yuan; Li, Keng-Yuan; Lin, Chun-Pin; Lin, Feng-Huei

    2016-06-01

    Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure. Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible

  12. Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, B.D.; Bishop, S.M. [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States); Leedy, K.D. [Air Force Research Laboratory, 2241 Avionics Circle, Wright Patterson Air Force Base, Dayton, OH 45433 (United States); Cady, N.C., E-mail: ncady@albany.edu [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States)

    2014-07-01

    Hafnium oxide-based resistive memory devices have been fabricated on copper bottom electrodes. The HfO{sub x} active layers in these devices were deposited by atomic layer deposition (ALD) at 250 °C with tetrakis(dimethylamido)hafnium(IV) as the metal precursor and an O{sub 2} plasma as the reactant. Depth profiles of the HfO{sub x} by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a copper concentration on the order of five atomic percent throughout the HfO{sub x} film. In addition to the Cu doped HfO{sub x}, a thin layer (20 nm) of Cu{sub x}O is present at the surface. This surface layer is believed to have formed during the ALD process, and greatly complicates the analysis of the switching mechanism. The resistive memory structures fabricated from the ALD HfO{sub x} exhibited non-polar resistive switching, independent of the top metal electrode (Ni, Pt, Al, Au). Resistive switching current voltage (I–V) curves were analyzed using Schottky emission and ionic hopping models to gain insight into the physical mechanisms underpinning the device behavior. During the forming process it was determined that, at voltages in excess of 2.5 V, an ionic hopping model is in good agreement with the I–V data. The extracted ion hopping distance ∼ 4 Å was within the range of interatomic spacing of HfO{sub 2} during the forming process consistent with ionic motion of Cu{sup 2+} ions. Lastly the on state I–V data was dominated at larger voltages by Schottky emission with an estimated barrier height of ∼ 0.5 eV and a refractive index of 2.59. The consequence of the Schottky emission analysis indicates the on state resistance to be a product of a Pt/Cu{sub 2}O/Cu filament(s)/Cu{sub 2}O/Cu structure. - Highlights: • HfO{sub 2} was grown via atomic layer deposition at 250 and 100 °C on Cu substrates. • A Cu{sub 2}O surface layer and Cu doping were observed in post-deposition of HfO{sub 2}. • Resistive memory devices were fabricated and

  13. Recoil Induced Room Temperature Stable Frenkel Pairs in a-Hafnium Upon Thermal Neutron Capture

    Science.gov (United States)

    Butz, Tilman; Das, Satyendra K.; Dey, Chandi C.; Ghoshal, Shamik

    2013-11-01

    Ultrapure hafnium metal (110 ppm zirconium) was neutron activated with a thermal neutron flux of 6:6 · 1012 cm-2s-1 in order to obtain 181Hf for subsequent time differential perturbed angular correlation (TDPAC) experiments using the nuclear probe 181Hf(β-) 181Ta. Apart from the expected nuclear quadrupole interaction (NQI) signal for a hexagonal close-packed (hcp) metal, three further discrete NQIs were observed with a few percent fraction each. The TDPAC spectra were recorded for up to 11 half lives with extreme statistical accuracy. The fitted parameters vary slightly within the temperature range between 248 K and 373 K. The signals corresponding to the three additional sites completely disappear after `annealing' at 453 K for one minute. Based on the symmetry of the additional NQIs and their temperature dependencies, they are tentatively attributed to Frenkel pairs produced by recoil due to the emission of a prompt 5:694 MeV -ray following thermal neutron capture and reported by the nuclear probe in three different positions. These Frenkel pairs are stable up to at least 373 K.

  14. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface

    Science.gov (United States)

    Nguyen, Duc; Mallek, Justin; Cloud, Andrew N.; Abelson, John R.; Girolami, Gregory S.; Lyding, Joseph; Gruebele, Martin

    2014-11-01

    Direct visualization of the dynamics of structural glasses and amorphous solids on the sub-nanometer scale provides rich information unavailable from bulk or conventional single molecule techniques. We study the surface of hafnium diboride, a conductive ultrahigh temperature ceramic material that can be grown in amorphous films. Our scanning tunneling movies have a second-to-hour dynamic range and single-point current measurements extend that to the millisecond-to-minute time scale. On the a-HfB2 glass surface, two-state hopping of 1-2 nm diameter cooperatively rearranging regions or "clusters" occurs from sub-milliseconds to hours. We characterize individual clusters in detail through high-resolution (single cluster vertical displacements, we can reconstruct the local free energy landscape of individual clusters, complete with activation barrier height, a reaction coordinate in nanometers, and the shape of the free energy landscape basins between which hopping occurs. The experimental images are consistent with the compact shape of α-relaxors predicted by random first order transition theory, whereas the rapid hopping rate, even taking less confined motion at the surface into account, is consistent with β-relaxations. We make a proposal of how "mixed" features can show up in surface dynamics of glasses.

  15. Characteristics of laser produced plasmas of hafnium and tantalum in the 1-7 nm region

    Science.gov (United States)

    Li, Bowen; Otsuka, Takamitsu; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry; Hara, Hiroyuki; Arai, Goki; Tamura, Toshiki; Ono, Yuichi; Dinh, Thanh-Hung; Higashiguchi, Takeshi

    2017-11-01

    Soft X-ray (SXR) spectra from hafnium and tantalum laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 170 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 2. 3 × 1014 W cm-2 for 170 ps pulses and 1. 8 × 1012 W cm-2 for 10 ns pulses, respectively. Two intense quasicontinuous intensity bands resulting from n = 4 - n = 4 and n = 4 - n = 5 unresolved transition arrays (UTAs) dominate both sets of experimental spectra. Comparison with calculations performed with the Cowan suite of atomic structure codes as well as consideration of previous experimental and theoretical results aided identification of the most prominent features in the spectra. For the 10 ns spectrum, the highest ion stage that could be identified from the n = 4 - n = 5 arrays were lower than silver-like Hf25+ and Ta26+ (which has a 4 d 104 f ground configuration) indicating that the plasma temperature attained was too low to produce ions with an outermost 4 d subshell, while for the 170 ps plasmas the presence of significantly higher stages was deduced and lines due to 4 d-5 p transitions were clearly evident. Furthermore, we show an enhancement of emission from tantalum using dual laser irradiation, and the effect of pre-pulse durations and delay times between two pulses are demonstrated.

  16. Ferroelectric transistors with monolayer molybdenum disulfide and ultra-thin aluminum-doped hafnium oxide

    Science.gov (United States)

    Yap, Wui Chung; Jiang, Hao; Liu, Jialun; Xia, Qiangfei; Zhu, Wenjuan

    2017-07-01

    In this letter, we demonstrate ferroelectric memory devices with monolayer molybdenum disulfide (MoS2) as the channel material and aluminum (Al)-doped hafnium oxide (HfO2) as the ferroelectric gate dielectric. Metal-ferroelectric-metal capacitors with 16 nm thick Al-doped HfO2 are fabricated, and a remnant polarization of 3 μC/cm2 under a program/erase voltage of 5 V is observed. The capability of potential 10 years data retention was estimated using extrapolation of the experimental data. Ferroelectric transistors based on embedded ferroelectric HfO2 and MoS2 grown by chemical vapor deposition are fabricated. Clockwise hysteresis is observed at low program/erase voltages due to slow bulk traps located near the 2D/dielectric interface, while counterclockwise hysteresis is observed at high program/erase voltages due to ferroelectric polarization. In addition, the endurances of the devices are tested, and the effects associated with ferroelectric materials, such as the wake-up effect and polarization fatigue, are observed. Reliable writing/reading in MoS2/Al-doped HfO2 ferroelectric transistors over 2 × 104 cycles is achieved. This research can potentially lead to advances of two-dimensional (2D) materials in low-power logic and memory applications.

  17. Silicon-doped hafnium oxide anti-ferroelectric thin films for energy storage

    Science.gov (United States)

    Ali, Faizan; Liu, Xiaohua; Zhou, Dayu; Yang, Xirui; Xu, Jin; Schenk, Tony; Müller, Johannes; Schroeder, Uwe; Cao, Fei; Dong, Xianlin

    2017-10-01

    Motivated by the development of ultracompact electronic devices as miniaturized energy autonomous systems, great research efforts have been expended in recent years to develop various types of nano-structural energy storage components. The electrostatic capacitors characterized by high power density are competitive; however, their implementation in practical devices is limited by the low intrinsic energy storage density (ESD) of linear dielectrics like Al2O3. In this work, a detailed experimental investigation of energy storage properties is presented for 10 nm thick silicon-doped hafnium oxide anti-ferroelectric thin films. Owing to high field induced polarization and slim double hysteresis, an extremely large ESD value of 61.2 J/cm3 is achieved at 4.5 MV/cm with a high efficiency of ˜65%. In addition, the ESD and the efficiency exhibit robust thermal stability in 210-400 K temperature range and an excellent endurance up to 109 times of charge/discharge cycling at a very high electric field of 4.0 MV/cm. The superior energy storage performance together with mature technology of integration into 3-D arrays suggests great promise for this recently discovered anti-ferroelectric material to replace the currently adopted Al2O3 in fabrication of nano-structural supercapacitors.

  18. Hafnium Films and Magnetic Shielding for TIME, A mm-Wavelength Spectrometer Array

    Science.gov (United States)

    Hunacek, J.; Bock, J.; Bradford, C. M.; Butler, V.; Chang, T.-C.; Cheng, Y.-T.; Cooray, A.; Crites, A.; Frez, C.; Hailey-Dunsheath, S.; Hoscheit, B.; Kim, D. W.; Li, C.-T.; Marrone, D.; Moncelsi, L.; Shirokoff, E.; Steinbach, B.; Sun, G.; Trumper, I.; Turner, A.; Uzgil, B.; Weber, A.; Zemcov, M.

    2018-04-01

    TIME is a mm-wavelength grating spectrometer array that will map fluctuations of the 157.7-μm emission line of singly ionized carbon ([CII]) during the epoch of reionization (redshift z ˜ 5-9). Sixty transition-edge sensor (TES) bolometers populate the output arc of each of the 32 spectrometers, for a total of 1920 detectors. Each bolometer consists of gold absorber on a ˜ 3 × 3 mm silicon nitride micro-mesh suspended near the corners by 1 × 1 × 500 μm silicon nitride legs targeting a photon-noise-dominated NEP ˜ 1 × 10^{-17} W/√{Hz} . Hafnium films are explored as a lower-T_c alternative to Ti (500 mK) for TIME TESs, allowing thicker support legs for improved yield. Hf T_c is shown to vary between 250 and 450 mK when varying the resident Ar pressure during deposition. Magnetic shielding designs and simulations are presented for the TIME first-stage SQUIDs. Total axial field suppression is predicted to be 5 × 10^7.

  19. Tuning the magnetic properties of pure hafnium by high pressure torsion

    International Nuclear Information System (INIS)

    Cepeda-Jiménez, C.M.; Beltrán, J.I.; Hernando, A.; García, M.A.; Ynduráin, F.; Zhilyaev, A.; Pérez-Prado, M.T.

    2017-01-01

    This work demonstrates that room temperature (RT) ferromagnetism might be triggered in pure hafnium (Hf), a classic paramagnet, by severe plastic deformation (SPD) via high pressure torsion (HPT). The origin of this phenomenon is elucidated by a combined approach including density functional theory (DFT) calculations and transmission electron microscopy (TEM). In particular, it is shown that the elastic lattice distorsions induced in pure Hf as a consequence of grain refinement down to the nanocrystalline regime by HPT lead to the development of a new monoclinic crystalline structure that exhibits a spontaneous magnetization at RT. DFT calculations are utilized to prove that local stretching of the original pure Hf hexagonal close packed (hcp) lattice along specific pyramidal directions, due to the presence of internal stresses in the deformed nanostructure, may give rise to the emergence of the monoclinic phase, which is endowed with a net magnetic moment. An excellent agreement is found between DFT calculations and experimental TEM observations, which provide a first evidence of the presence of the pure Hf monoclinic crystal lattice. This work shows that SPD may constitute a viable, yet widely unexplored, strategy to tune the magnetic properties and, in particular, to induce RT ferromagnetism in bulk non-magnetic metals.

  20. Population of Metastable States in Stable Hafnium and Ytterbium Nuclei via Beam Break-up

    International Nuclear Information System (INIS)

    Malwela, T.; Ntshangase, S.S.; Shirinda, O.; Bark, R.A.; Gueorguieva, E.; Lawrie, J.J.; Mullins, S.M.; Murray, S.H.T.; Sharpey-Schafer, J.F.; Gal, J.; Kalinka, G.; Krasznahorkay, A.; Molnar, J.; Nyako, B.M.; Timar, J.; Zolnai, L.; Hlatshwayo, T.; Juhasz, K.; Komati, F.S.; Scheurer, J.N.

    2005-01-01

    The ''Chessboard'' section of the DIAMANT charged-particle array has been coupled with the AFRODITE γ-ray spectrometer at the iThemba Laboratory for Accelerator Based Sciences. Charged-particle-γ-ray coincidence data were recorded during the bombardment of a 176Yb target with a 13C beam at an energy of 90 MeV. The purpose of the investigation was to study the population of metastable states in hafium nuclei via incomplete fusion reactions in which the beam breaks up due to its α-cluster character. Of note was the observation of the band based on the Kπ = 16+, T1/2 = 31 year isomer in 178Hf to its 19+ member. Also, decays from the high-K isomeric states in 174Yb and 176Yb. which were populated via 3αxn channels, indicative of complete break-up of the 13C beam

  1. In-Pile Experiment of a New Hafnium Aluminide Composite Material to Enable Fast Neutron Testing in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Douglas L. Porter; James R. Parry; Heng Ban

    2010-06-01

    A new hafnium aluminide composite material is being developed as a key component in a Boosted Fast Flux Loop (BFFL) system designed to provide fast neutron flux test capability in the Advanced Test Reactor. An absorber block comprised of hafnium aluminide (Al3Hf) particles (~23% by volume) dispersed in an aluminum matrix can absorb thermal neutrons and transfer heat from the experiment to pressurized water cooling channels. However, the thermophysical properties, such as thermal conductivity, of this material and the effect of irradiation are not known. This paper describes the design of an in-pile experiment to obtain such data to enable design and optimization of the BFFL neutron filter.

  2. Rapid formation of nanocrystalline HfO2 powders from amorphous hafnium hydroxide under ultrasonically assisted hydrothermal treatment

    International Nuclear Information System (INIS)

    Meskin, Pavel E.; Sharikov, Felix Yu.; Ivanov, Vladimir K.; Churagulov, Bulat R.; Tretyakov, Yury D.

    2007-01-01

    Peculiarities of hafnium hydroxide hydrothermal decomposition were studied by in situ heat flux calorimetry for the first time. It was shown that this process occurs in one exothermal stage (ΔH = -17.95 kJ mol -1 ) at 180-250 deg. C resulting in complete crystallization of amorphous phase with formation of pure monoclinic HfO 2 . It was found that the rate of m-HfO 2 formation can be significantly increased by combining hydrothermal treatment with simultaneous ultrasonic activation

  3. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface

    International Nuclear Information System (INIS)

    Nguyen, Duc; Girolami, Gregory S.; Mallek, Justin; Cloud, Andrew N.; Abelson, John R.; Lyding, Joseph; Gruebele, Martin

    2014-01-01

    Direct visualization of the dynamics of structural glasses and amorphous solids on the sub-nanometer scale provides rich information unavailable from bulk or conventional single molecule techniques. We study the surface of hafnium diboride, a conductive ultrahigh temperature ceramic material that can be grown in amorphous films. Our scanning tunneling movies have a second-to-hour dynamic range and single-point current measurements extend that to the millisecond-to-minute time scale. On the a-HfB 2 glass surface, two-state hopping of 1–2 nm diameter cooperatively rearranging regions or “clusters” occurs from sub-milliseconds to hours. We characterize individual clusters in detail through high-resolution (<0.5 nm) imaging, scanning tunneling spectroscopy and voltage modulation, ruling out individual atoms, diffusing adsorbates, or pinned charges as the origin of the observed two-state hopping. Smaller clusters are more likely to hop, larger ones are more likely to be immobile. HfB 2 has a very high bulk glass transition temperature T g , and we observe no three-state hopping or sequential two-state hopping previously seen on lower T g glass surfaces. The electronic density of states of clusters does not change when they hop up or down, allowing us to calibrate an accurate relative z-axis scale. By directly measuring and histogramming single cluster vertical displacements, we can reconstruct the local free energy landscape of individual clusters, complete with activation barrier height, a reaction coordinate in nanometers, and the shape of the free energy landscape basins between which hopping occurs. The experimental images are consistent with the compact shape of α-relaxors predicted by random first order transition theory, whereas the rapid hopping rate, even taking less confined motion at the surface into account, is consistent with β-relaxations. We make a proposal of how “mixed” features can show up in surface dynamics of glasses

  4. Materials properties of hafnium and zirconium silicates: Metal interdiffusion and dopant penetration studies

    Science.gov (United States)

    Quevedo Lopez, Manuel Angel

    Hafnium and Zirconium based gate dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in CMOS processing. Furthermore, the addition of nitrogen into this pseudo-binary alloy has been shown to improve their thermal stability, electrical properties, and reduce dopant penetration. Because CMOS processing requires high temperature anneals (up to 1050°C), it is important to understand the diffusion properties of any metal associated with the gate dielectric in silicon at these temperatures. In addition, dopant penetration from the doped polysilicon gate into the Si channel at these temperatures must also be studied. Impurity outdiffusion (Hf, Zr) from the dielectric, or dopant (B, As, P) penetration through the dielectric into the channel region would likely result in deleterious effects upon the carrier mobility. In this dissertation extensive thermal stability studies of alternate gate dielectric candidates ZrSixOy and HfSixO y are presented. Dopant penetration studies from doped-polysilicon through HfSixOy and HfSixOyNz are also presented. Rutherford Backscattering Spectroscopy (RBS), Heavy Ion RBS (HI-RBS), X-ray Photoelectron Spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HR-TEM), and Time of Flight and Dynamic Secondary Ion Mass Spectroscopy (ToF-SIMS, D-SIMS) methods were used to characterize these materials. The dopant diffusivity is calculated by modeling of the dopant profiles in the Si substrate. In this disseration is reported that Hf silicate films are more stable than Zr silicate films, from the metal interdiffusion point of view. On the other hand, dopant (B, As, and P) penetration is observed for HfSixO y films. However, the addition of nitrogen to the Hf - Si - O systems improves the dopant penetration properties of the resulting HfSi xOyNz films.

  5. Protective coatings of hafnium dioxide by atomic layer deposition for microelectromechanical systems applications

    Energy Technology Data Exchange (ETDEWEB)

    Berdova, Maria, E-mail: maria.berdova@aalto.fi [Aalto University, Department of Materials Science and Engineering, 02150, Espoo (Finland); Wiemer, Claudia; Lamperti, Alessio; Tallarida, Grazia; Cianci, Elena [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Lamagna, Luca; Losa, Stefano; Rossini, Silvia; Somaschini, Roberto; Gioveni, Salvatore [STMicroelectronics, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Fanciulli, Marco [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Università degli studi di Milano Bicocca, Dipartimento di Scienza dei Materiali, 20126, Milano (Italy); Franssila, Sami, E-mail: sami.franssila@aalto.fi [Aalto University, Department of Materials Science and Engineering, 02150, Espoo (Finland)

    2016-04-15

    Graphical abstract: - Highlights: • Atomic layer deposition of HfO{sub 2} from (CpMe){sub 2}Hf(OMe)Me or Hf(NMeEt){sub 4} and ozone for potential applications in microelectromechanical systems. • ALD HfO{sub 2} protects aluminum substrates from degradation in moist environment and at the same time retains good reflectance properties of the underlying material. • The resistance of hafnium dioxide to moist environment is independent of chosen precursors. - Abstract: This work presents the investigation of HfO{sub 2} deposited by atomic layer deposition (ALD) from either HfD-CO4 or TEMAHf and ozone for microelectromechanical systems (MEMS) applications, in particular, for environmental protection of aluminum micromirrors. This work shows that HfO{sub 2} films successfully protect aluminum in moist environment and at the same time retain good reflectance properties of underlying material. In our experimental work, the chemical composition, crystal structure, electronic density and roughness of HfO{sub 2} films remained the same after one week of humidity treatment (relative humidity of 85%, 85 °C). The reflectance properties underwent only minor changes. The observed shift in reflectance was only from 80–90% to 76–85% in 400–800 nm spectral range when coated with ALD HfO{sub 2} films grown with Hf(NMeEt){sub 4} and no shift (remained in the range of 68–83%) for films grown from (CpMe){sub 2}Hf(OMe)Me.

  6. Study of hafnium (IV) oxide nanoparticles synthesized by polymerized complex and polymer precursor derived sol-gel methods

    KAUST Repository

    Ramos-Gonzá lez, R.; Garcí a-Cerda, L. A.; Alshareef, Husam N.; Gnade, Bruce E.; Quevedo-Ló pez, Manuel Angel Quevedo

    2010-01-01

    This work reports the preparation and characterization of hafnium (IV) oxide (HfO2) nanoparticles grown by derived sol-gel routes that involves the formation of an organic polymeric network. A comparison between polymerized complex (PC) and polymer precursor (PP) methods is presented. For the PC method, citric acid (CA) and ethylene glycol (EG) are used as the chelating and polymerizable reagents, respectively. In the case of PP method, poly(acrylic acid) (PAA) is used as the chelating reagent. In both cases, different precursor gels were prepared and the hafnium (IV) chloride (HfCl4) molar ratio was varied from 0.1 to 1.0 for the PC method and from 0.05 to 0.5 for the PP method. In order to obtain the nanoparticles, the precursors were heat treated at 500 and 800 °C. The thermal characterization of the precursor gels was carried out by thermogravimetric analysis (TGA) and the structural and morphological characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the samples obtained by both methods shows the formation of HfO2 at 500 °C with monoclinic crystalline phase. The PC method exhibited also the cubic phase. Finally, the HfO2 nanoparticles size (4 to 11 nm) was determined by TEM and XRD patterns. © (2010) Trans Tech Publications.

  7. Study of hafnium (IV) oxide nanoparticles synthesized by polymerized complex and polymer precursor derived sol-gel methods

    KAUST Repository

    Ramos-González, R.

    2010-03-01

    This work reports the preparation and characterization of hafnium (IV) oxide (HfO2) nanoparticles grown by derived sol-gel routes that involves the formation of an organic polymeric network. A comparison between polymerized complex (PC) and polymer precursor (PP) methods is presented. For the PC method, citric acid (CA) and ethylene glycol (EG) are used as the chelating and polymerizable reagents, respectively. In the case of PP method, poly(acrylic acid) (PAA) is used as the chelating reagent. In both cases, different precursor gels were prepared and the hafnium (IV) chloride (HfCl4) molar ratio was varied from 0.1 to 1.0 for the PC method and from 0.05 to 0.5 for the PP method. In order to obtain the nanoparticles, the precursors were heat treated at 500 and 800 °C. The thermal characterization of the precursor gels was carried out by thermogravimetric analysis (TGA) and the structural and morphological characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the samples obtained by both methods shows the formation of HfO2 at 500 °C with monoclinic crystalline phase. The PC method exhibited also the cubic phase. Finally, the HfO2 nanoparticles size (4 to 11 nm) was determined by TEM and XRD patterns. © (2010) Trans Tech Publications.

  8. Chronic subdural hematoma: epidemiological and prognostic analysis of 176 cases

    Directory of Open Access Journals (Sweden)

    JAMIL FARHAT NETO

    Full Text Available Objective : To characterize patients with chronic subdural hematoma undergoing surgery and to identify prognostic indicators. Methods : We conducted a retrospective analysis of patients diagnosed with chronic subdural hematoma (CSDH undergoing surgical treatment. We analyzed: age, period from trauma to diagnostic imaging, pre and postoperative Glasgow coma scale, type of surgery, associated comorbidities, use of postoperative drainage and outpatient treatment. Results : The sample consisted of 176 patients, 126 male and 50 female patients (ratio 2.5 : 1, ages ranged from six months to 97 years, with an average of 59.3 years. CSDH was caused by trauma in 52% of patients, with the time from trauma to imaging averaging 25.05 days; 37.7% were hypertensive patients and 20% had a neurological disease. Eighty-five (48.3% patients were elderly and altered consciousness was present in 63% of cases. Of the 91 (51.7% non-elderly patients, 44% presented with headache, altered consciousness occurred in 40% and motor abnormalities in 27.5%. The CSDH was located on the right in 41%, left in 43% and bilaterally in 16% of patients. Conclusion : the change of consciousness was the most common clinical alteration in the elderly and headache in non-elderly. The most associated comorbidity was the arterial hypertension and the most frequent cause, head trauma. The trepanation with two oriffices associated with a closed drainage system was the most used operating, with high efficacy and low complication rate.

  9. Dipole compensation of the 176 MHz MYRRHA RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Kuempel, Klaus; Podlech, Holger; Lenz, Christoph; Petry, Nils [IAP, University of Frankfurt, Frankfurt am Main (Germany); Bechtold, Alexander [NTG Neue Technologien GmbH und Co.KG, Gelnhausen (Germany); Zhang, Chuan [GSI Helmholtzzentrum, Darmstadt (Germany)

    2016-07-01

    The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is planned as an accelerator driven system (ADS) for the transmutation of long-living radioactive waste. For this project a cw 4-rod-RFQ with 176 MHz and a total length of about 4 m is required. It is supposed to accelerate protons from 30 keV up to 1.5 MeV*. One of the main tasks during the development of the RFQ is the very high reliability of the accelerator to limit the thermal stress inside the reactor. Another challenge was to compensate the dipole component of the MYRRHA-RFQ which is due to the design principle of 4-rod-RFQs. This dipole component is responsible for shifting the ideal beam axis from the geometrical center of the quadrupole downwards. Design studies with CST MICROWAVE STUDIO have shown that the dipole component can be almost completely compensated by widening the stems alternately so that the current paths of the lower electrodes are increased.

  10. 19 CFR 176.22 - Deletion of protest or entry number.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Deletion of protest or entry number. 176.22... Facts § 176.22 Deletion of protest or entry number. If any protest number or entry number is to be... authorized official making and approving the deletion. [T.D. 70-181, 35 FR 13433, Aug. 22, 1970] ...

  11. 40 CFR 265.176 - Special requirements for ignitable or reactive waste.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Special requirements for ignitable or reactive waste. 265.176 Section 265.176 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE...

  12. 40 CFR 264.176 - Special requirements for ignitable or reactive waste.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Special requirements for ignitable or reactive waste. 264.176 Section 264.176 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE...

  13. 31 CFR 363.176 - May a converted savings bond be pledged or used as collateral?

    Science.gov (United States)

    2010-07-01

    ... pledged or used as collateral? 363.176 Section 363.176 Money and Finance: Treasury Regulations Relating to... a converted savings bond be pledged or used as collateral? A converted savings bond may not be pledged or used as collateral for the performance of an obligation. ...

  14. 2 CFR 176.90 - Non-application to acquisitions covered under international agreements.

    Science.gov (United States)

    2010-01-01

    ... are: (1) The World Trade Organization Government Procurement Agreement (Aruba, Austria, Belgium... under international agreements. 176.90 Section 176.90 Grants and Agreements OFFICE OF MANAGEMENT AND...-application to acquisitions covered under international agreements. Acquisitions covered by international...

  15. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed with...

  16. Nuclear high-spin data for A = 174, 176 and 184

    Energy Technology Data Exchange (ETDEWEB)

    Junde, Huo [Jilin Univ. (China). Dept. of Physics

    1996-06-01

    Nuclear high-spin data are important in the frontier areas of nuclear structure physics. The information on A = 174, 176 and 184 mass chains from various reaction experiments together with their adopted high-spin levels and gamma transition properties are presented and discussed. High-spin data for A = 174, 176 and 184 mass chains were evaluated in 1995.

  17. 49 CFR 176.54 - Repairs involving welding, burning, and power-actuated tools and appliances.

    Science.gov (United States)

    2010-10-01

    ...-actuated tools and appliances. 176.54 Section 176.54 Transportation Other Regulations Relating to..., burning, and power-actuated tools and appliances. (a) Except as provided in paragraph (b) of this section, repairs or work involving welding or burning, or the use of power-actuated tools or appliances which may...

  18. Corrosion resistant surface for vanadium nitride and hafnium nitride layers as function of grain size

    Science.gov (United States)

    Escobar, C. A.; Caicedo, J. C.; Aperador, W.

    2014-01-01

    In this research it was studied vanadium nitride (VN) and hafnium nitride (HfN) film, which were deposited onto silicon (Si (100)) and AISI 4140 steel substrates via r.f. magnetron sputtering technique in Ar/N2 atmosphere with purity at 99.99% for both V and Hf metallic targets. Both films were approximately 1.2±0.1 μm thick. The crystallography structures that were evaluated via X-ray diffraction analysis (XRD) showed preferential orientations in the Bragg planes VN (200) and HfN (111). The chemical compositions for both films were characterized by EDX. Atomic Force Microscopy (AFM) was used to study the morphology; the results reveal grain sizes of 78±2 nm for VN and 58±2 nm for HfN and roughness values of 4.2±0.1 nm for VN and 1.5±0.1 nm for HfN films. The electrochemical performance in VN and HfN films deposited onto steel 4140 were studied by Tafel polarization curves and impedance spectroscopy methods (EIS) under contact with sodium chloride at 3.5 wt% solution, therefore, it was found that the corrosion rate decreased about 95% in VN and 99% for HfN films in relation to uncoated 4140 steel, thus demonstrating, the protecting effect of VN and HfN films under a corrosive environment as function of morphological characteristics (grain size). VN(grain size)=78±2.0 nm, VN(roughness)=4.2±0.1 nm, VN(corrosion rate)=40.87 μmy. HfN(grain size)=58±2.0 nm, HfN(roughness)=1.5±0.1 nm, HfN(corrosion rate)=0.205 μmy. It was possible to analyze that films with larger grain size, can be observed smaller grain boundary thus generating a higher corrosion rate, therefore, in this work it was found that the HfN layer has better corrosion resistance (low corrosion rate) in relation to VN film which presents a larger grain size, indicating that the low grain boundary in (VN films) does not restrict movement of the Cl- ion and in this way the corrosion rate increases dramatically.

  19. Synthesis and characterization of hafnium carbide microcrystal chains with a carbon-rich shell via CVD

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Liu, Sen; Fu, Yangxi; Li, Yixian; Qiang, Xinfa

    2013-01-01

    Graphical abstract: Novel HfC microcrystal chains have been synthesized via a catalyst-assisted chemical vapor deposition process. SEM results show the chains have a periodically changing diameter and a nanoscale sharpening tip. Analysis of TEM/SAED/EELS/EDX data shows the single-crystal chains grow along a [0 0 1] direction and consist of a HfC core and a thin carbon-rich shell with embedded HfC nanocrystallites surrounding the core. This work achieves the controllable preparation of nanoscale HfC sharpening tips for application as a point electron emission source and facilitates the application of HfC ultrafast laser-triggered tips in attosecond science. Highlights: •HfC microcrystal chains were synthesized by a catalyst-assisted CVD. •The chains grow along a [0 0 1] direction and have a periodically changing diameter. •Single-crystal HfC core is sheathed by a thin carbon-rich shell. •A growth mechanism model is proposed to explain the growth of microcrystal chians. •This work achieves the controllable preparation of nanoscale HfC sharpening tips. -- Abstract: Novel hafnium carbide (HfC) microcrystal chains, with a periodically changing diameter and a nanoscale sharpening tip at the chain end, have been synthesized via a catalyst-assisted chemical vapor deposition (CVD) process. The as-synthesized chains with many octahedral microcrystals have diameters of between several hundreds of nm and 6 μm and lengths of ∼500 μm. TEM diffraction studies show that the chains are single-crystalline HfC and preferentially grow along a [0 0 1] crystal orientation. TEM/EELS/EDX analysis proves the chains are composed of a HfC core and a thin (several tens of nm to 100 nm) carbon-rich shell with the embedded HfC nanocrystallites (typically below 10 nm) surrounding the core. The growth mechanism model for the chains based on the vapor–liquid–solid process, the vapor–solid process, and the HfC crystal growth characteristics is discussed

  20. Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study

    International Nuclear Information System (INIS)

    Davis, Linda L.; Darab, John G.; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S.; Li, Hong; Strachan, Denis M.; Li, Liyu

    2003-01-01

    A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others

  1. Nano-crystals of cerium–hafnium binary oxide: Their size-dependent structure

    Energy Technology Data Exchange (ETDEWEB)

    Raitano, Joan M. [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States); Khalid, Syed [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973 (United States); Marinkovic, Nebojsa [Chemical Engineering Department, Columbia University, 500 W 120th St, Mudd 801, New York, NY 10027 (United States); Chan, Siu-Wai, E-mail: sc174@columbia.edu [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States)

    2015-09-25

    Highlights: • (1 − x)CeO{sub 2}–xHfO{sub 2} was precipitated (0 < x < 1) and calcined in air. • For x ⩽ 0.14, crystallites ⩽140 nm in size exhibit only the fluorite structure. • This low hafnia solubility is attributable to no auto-reduction (Ce{sup 3+} = 0). • The low solubility is also due to the high temperature required for homogenization. • Coarsening is lessened as Hf{sup 4+} ions slow cation diffusion in these crystallites. - Abstract: Cerium oxide (CeO{sub 2}, “ceria”) and hafnium oxide (HfO{sub 2}, “hafnia”) were aqueously co-precipitated and subsequently calcined to allow for homogenization. The size of the (1−x)CeO{sub 2}–xHfO{sub 2} crystallites, determined by the Scherrer equation, varied from 140 nm for x = 0 to 15 nm for x = 0.73. For x ⩽ 0.14, only cubic structures are visible in X-ray diffractograms, and the lattice parameters are consistent with the values expected for structurally cubic solid solutions of hafnia in ceria. At x = 0.26, tetragonal and monoclinic phases nucleated with the former not being observed in the bulk phase diagram for ceria–hafnia. Therefore, the solubility limit of the cubic structure is between x = 0.14 and x = 0.26 for 40–61 nm crystallites, the sizes of these respective compositions. More specifically, for the 40 nm crystallites of x = 0.26 (1 − x)CeO{sub 2}–xHfO{sub 2}, 15% of the hafnia remains in a structurally cubic solid solution with ceria based on the observed cubic lattice parameter. The compositional domain for the cubic fluorite structure in this study is narrower than other nanostructured (1 − x)CeO{sub 2}–xHfO{sub 2} studies, especially studies with crystallite sizes less than 10 nm, but wider than observed in the bulk and helps to expand the size regime over which the relationship between crystallite size and phase stability is known. The extent of this cubic-structure domain is mainly attributable to the intermediate crystallite size and the roughly zero Ce{sup 3

  2. A search for long-lived radionuclides produced by fast-neutron irradiations of copper, silver, europium, terbium, and hafnium

    International Nuclear Information System (INIS)

    Meadows, J.W.; Smith, D.L.; Ikeda, Y.; Konno, C.

    1990-01-01

    Identical sample packets, each containing samples of elemental copper, silver, europium, terbium, and hafnium, as well as titanium, iron and nickel as dosimeters, have been irradiated in three distinct accelerator neutron fields (at Argonne National Laboratory and Los Alamos National Laboratory in the U.S.A., and Japan Atomic Energy Research Institute, Tokai, Japan) as part of an interlaboratory research collaboration to search for the production of long-lived radionuclides for fusion waste disposal applications. This paper is a progress report on this project. To date, we have detected the following activities, and have obtained preliminary experimental cross section values for several of these: Ag-106m,108m,110m; Eu-150m,152g,154; Tb-158,160; and Hf-175,178m2,179m2,181. (author). 11 refs, 1 fig., 4 tabs

  3. Improved DC performance of AlGaN/GaN high electron mobility transistors using hafnium oxide for surface passivation

    International Nuclear Information System (INIS)

    Liu, Chang; Chor, Eng Fong; Tan, Leng Seow

    2007-01-01

    Improved DC performance of AlGaN/GaN high electron mobility transistors (HEMTs) have been demonstrated using reactive-sputtered hafnium oxide (HfO 2 ) thin film as the surface passivation layer. Hall data indicate a significant increase in the product of sheet carrier concentration (n s ) and electron mobility (μ n ) in the HfO 2 -passivated HEMTs, compared to the unpassivated HEMTs. This improvement in electron carrier characteristics gives rise to a 22% higher I Dmax and an 18% higher g mmax in HEMTs with HfO 2 passivation relative to the unpassivated devices. On the other hand, I gleak of the HEMTs decreases by nearly one order of magnitude when HfO 2 passivation is applied. In addition, drain current is measured in the subthreshold regime. Compared to the unpassivated HEMTs, HfO 2 -passivated HEMTs exhibit a much smaller off-state I D , indicating better turn-off characteristics

  4. About the structure and stability of complex carbonates of thorium (IV), cerium (IV), zirconium (IV), hafnium (IV)

    International Nuclear Information System (INIS)

    Dervin, Jacqueline

    1972-01-01

    This research thesis addressed the study of complex carbonates of cations of metals belonging to the IV A column, i.e. thorium (IV), zirconium (IV), hafnium (IV), and also cerium (IV) and uranium (VI), and more particularly focused on ionic compounds formed in solution, and also on the influence of concentration and nature of cations on stability and nature of the formed solid. The author first presents methods used in this study, discusses their precision and scope of validity. She reports the study of the formation of different complex ions which have been highlighted in solution, and the determination of their formation constants. She reports the preparation and study of the stability domain of solid complexes. The next part reports the use of thermogravimetric analysis, IR spectrometry, and crystallography for the structural study of these compounds

  5. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    Science.gov (United States)

    Mora, M.; Vera, E.; Aperador, W.

    2016-02-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers.

  6. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    International Nuclear Information System (INIS)

    Mora, M; Vera, E; Aperador, W

    2016-01-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers. (paper)

  7. The interfacial orientation relationship of oxide nanoparticles in a hafnium-containing oxide dispersion-strengthened austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinbin, E-mail: miao2@illinois.edu [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Mo, Kun [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60493 (United States); Cui, Bai [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States); Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Chen, Wei-Ying [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Miller, Michael K.; Powers, Kathy A. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); McCreary, Virginia; Gross, David [Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Almer, Jonathan [X-ray Science Division, Argonne National Laboratory, Lemont, IL 60493 (United States); Robertson, Ian M. [Department of Material Science and Engineering, University of Wisconsin-Madison, Madison, WA 53706 (United States); Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Stubbins, James F. [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2015-03-15

    This work reports comprehensive investigations on the orientation relationship of the oxide nanoparticles in a hafnium-containing austenitic oxide dispersion-strengthened 316 stainless steel. The phases of the oxide nanoparticles were determined by a combination of scanning transmission electron microscopy–electron dispersive X-ray spectroscopy, atom probe tomography and synchrotron X-ray diffraction to be complex Y–Ti–Hf–O compounds with similar crystal structures, including bixbyite Y{sub 2}O{sub 3}, fluorite Y{sub 2}O{sub 3}–HfO{sub 2} solid solution and pyrochlore (or fluorite) Y{sub 2}(Ti,Hf){sub 2−x}O{sub 7−x}. High resolution transmission electron microscopy was used to characterize the particle–matrix interfaces. Two different coherency relationships along with one axis-parallel relation between the oxide nanoparticles and the steel matrix were found. The size of the nanoparticles significantly influences the orientation relationship. The results provide insight into the relationship of these nanoparticles with the matrix, which has implications for interpreting material properties as well as responses to radiation. - Highlights: • The oxide nanoparticles in a hafnium-containing austenitic ODS were characterized. • The nanoparticles are Y–Hf–Ti–O enriched phases according to APT and STEM–EDS. • Two coherency and an axis-parallel orientation relationships were found by HR-TEM. • Particle size has a prominent effect on the orientation relationship (OR). • Formation mechanism of the oxide nanoparticles was discussed based on the ORs.

  8. 49 CFR 17.6 - What procedures apply to the selection of programs and activities under these regulations?

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What procedures apply to the selection of programs and activities under these regulations? 17.6 Section 17.6 Transportation Office of the Secretary of Transportation INTERGOVERNMENTAL REVIEW OF DEPARTMENT OF TRANSPORTATION PROGRAMS AND ACTIVITIES § 17.6 What...

  9. Natural radioactive nuclides 138La and 176Lu in rare earth ore samples

    International Nuclear Information System (INIS)

    Zhang Weiping; Shen Jianfeng; Lu Zhaolun; Jiang Rangrong

    1993-01-01

    The contents of 1 '3 8 La and 176 Lu in some rare earth mines have been measured with a HPGE γ spectrometer. The measurements show that the contents of 138 La and 176 Lu in one rare earth mine are remarkably different from those in the other and they do not display a proportional relation, and that the contents of 40 K in this mine are very low

  10. Implantation of titanium, chromium, yttrium, molybdenum, silver, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum ion source into 440C stainless steel

    International Nuclear Information System (INIS)

    Sasaki, Jun; Hayashi, Kazunori; Sugiyama, Kenji; Ichiko, Osami; Hashiguchi, Yoshihiro

    1992-01-01

    Titanium, yttrium, molybdenum, silver, chromium, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum arc (MEVVA) ion source were implanted into 440C stainless steel in the dose region 10 17 ions cm -2 with extraction voltages of up to 70 kV. Glow discharge spectroscopy (GDS), friction coefficient, and Vickers microhardness of the specimens were studied. Grooves made by friction tests were investigated by electron probe microanalysis (EPMA). GDS showed incorporation of carbon in the yttrium, hafnium, tantalum, tungsten and platinum implanted specimens, as well as titanium implanted samples. A large amount of oxygen was observed in the yttrium implanted specimen. The friction coefficient was measured by reciprocating sliding of an unimplanted 440C ball without lubricant at a load of 0.245 N. The friction decreased and achieved a stable state after implantation of titanium, hafnium and tantalum. The friction coefficient of the platinum implanted specimen showed a gradual decrease after several cycles of sliding at high friction coefficient. The yttrium implanted sample exhibited a decreased but slightly unstable friction coefficient. Results from EPMA showed that the implanted elements, which gave decreased friction, remained even after sliding of 200 cycles. Implantation of chromium, molybdenum, silver and tungsten did not provide a decrease in friction and the implants were gone from the wear grooves after the sliding tests. (orig.)

  11. Significance of changes of levels of plasma proBNP1-76 in patients with chronic pulmonary heart disease

    International Nuclear Information System (INIS)

    Li Guizhong; Xu Hua; Cao Jun; Jiang Wei; Pang Yongzheng; Tang Chaoshu

    2003-01-01

    Objective: To investigate the significance of the changes levels of plasma proBNP 1-76 in patients with COPD and chronic pulmonary heart disease. Methods: Plasma proBNP 1-76 levels were determined with radioimmunoassay in patients with CHPD (n=23), COPD (n=24) and 32 controls. Results: The concentrations of plasma proBNP 1-76 in patients with chronic obstructive pulmonary disease were significantly increased (vs controls, p 1-76 (r=0.541, p 1-76 , right inferior pulmonary artery diameter, right ventricle out flow tract diameter and right ventricle anterior wall thickness in patients with chronic pulmonary heart disease were increased significantly (vs COPD patients and controls, p 1-76 (r=0.477, p 1-76 is an early marker of right ventricular hypertrophy and right ventricular dysfunction, measurement of which is useful in the management of patients with chronic pulmonary heart disease in daily practice

  12. Search for the return of activity in active asteroid 176P/LINEAR

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Henry H. [Institute for Astronomy and Astrophysics, Academia Sinica, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Denneau, Larry; Jedicke, Robert; Kaluna, Heather M.; Keane, Jacqueline V.; Kleyna, Jan; MacLennan, Eric M.; Meech, Karen J.; Riesen, Timm; Schunova, Eva; Urban, Laurie; Vereš, Peter; Wainscoat, Richard J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Fitzsimmons, Alan; Lacerda, Pedro [Astrophysics Research Centre, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Hainaut, Olivier R. [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching bei München (Germany); Ishiguro, Masateru [Department of Physics and Astronomy, Seoul National University, 599 Gwanak-ro, Gwanak, Seoul 151-742 (Korea, Republic of); Moskovitz, Nick A. [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Snodgrass, Colin [Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Trujillo, Chadwick A., E-mail: hhsieh@asiaa.sinica.edu.tw [Gemini Observatory, Northern Operations Center, 670 North Aohoku Place, Hilo, HI 96720 (United States); and others

    2014-04-01

    We present the results of a search for the reactivation of active asteroid 176P/LINEAR during its 2011 perihelion passage using deep optical observations obtained before, during, and after that perihelion passage. Deep composite images of 176P constructed from data obtained between 2011 June and 2011 December show no visible signs of activity, while photometric measurements of the object during this period also show no significant brightness enhancements similar to that observed for 176P between 2005 November and 2005 December when it was previously observed to be active. An azimuthal search for dust emission likewise reveals no evidence for directed emission (i.e., a tail, as was previously observed for 176P), while a one-dimensional surface brightness profile analysis shows no indication of a spherically symmetric coma at any time in 2011. We conclude that 176P did not in fact exhibit activity in 2011, at least not on the level on which it exhibited activity in 2005, and suggest that this could be due to the devolatization or mantling of the active site responsible for its activity in 2005.

  13. Novel Serine 176 Phosphorylation of YBX1 Activates NF-κB in Colon Cancer.

    Science.gov (United States)

    Martin, Matthew; Hua, Laiqing; Wang, Benlian; Wei, Han; Prabhu, Lakshmi; Hartley, Antja-Voy; Jiang, Guanglong; Liu, Yunlong; Lu, Tao

    2017-02-24

    Y box protein 1 (YBX1) is a well known oncoprotein that has tumor-promoting functions. YBX1 is widely considered to be an attractive therapeutic target in cancer. To develop novel therapeutics to target YBX1, it is of great importance to understand how YBX1 is finely regulated in cancer. Previously, we have shown that YBX1 could function as a tumor promoter through phosphorylation of its Ser-165 residue, leading to the activation of the NF-κB signaling pathway (1). In this study, using mass spectrometry analysis, we discovered a distinct phosphorylation site, Ser-176, on YBX1. Overexpression of the YBX1-S176A (serine-to-alanine) mutant in either HEK293 cells or colon cancer HT29 cells showed dramatically reduced NF-κB-activating ability compared with that of WT-YBX1, confirming that Ser-176 phosphorylation is critical for the activation of NF-κB by YBX1. Importantly, the mutant of Ser-176 and the previously reported Ser-165 sites regulate distinct groups of NF-κB target genes, suggesting the unique and irreplaceable function of each of these two phosphorylated serine residues. Our important findings could provide a novel cancer therapy strategy by blocking either Ser-176 or Ser-165 phosphorylation or both of YBX1 in colon cancer. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Mechanistic Studies of Hafnium-Pyridyl Amido-Catalyzed 1-Octene Polymerization and Chain Transfer Using Quench-Labeling Methods.

    Science.gov (United States)

    Cueny, Eric S; Johnson, Heather C; Anding, Bernie J; Landis, Clark R

    2017-08-30

    Chromophore quench-labeling applied to 1-octene polymerization as catalyzed by hafnium-pyridyl amido precursors enables quantification of the amount of active catalyst and observation of the molecular weight distribution (MWD) of Hf-bound polymers via UV-GPC analysis. Comparison of the UV-detected MWD with the MWD of the "bulk" (all polymers, from RI-GPC analysis) provides important mechanistic information. The time evolution of the dual-detection GPC data, concentration of active catalyst, and monomer consumption suggests optimal activation conditions for the Hf pre-catalyst in the presence of the activator [Ph 3 C][B(C 6 F 5 ) 4 ]. The chromophore quench-labeling agents do not react with the chain-transfer agent ZnEt 2 under the reaction conditions. Thus, Hf-bound polymeryls are selectively labeled in the presence of zinc-polymeryls. Quench-labeling studies in the presence of ZnEt 2 reveal that ZnEt 2 does not influence the rate of propagation at the Hf center, and chain transfer of Hf-bound polymers to ZnEt 2 is fast and quasi-irreversible. The quench-label techniques represent a means to study commercial polymerization catalysts that operate with high efficiency at low catalyst concentrations without the need for specialized equipment.

  15. An Auger electron spectroscopy study on the anodization process of high-quality thin-film capacitors made of hafnium

    International Nuclear Information System (INIS)

    Noya, Atsushi; Sasaki, Katsutaka; Umezawa, Toshiji

    1989-01-01

    Formation process of the anodic oxide film of hafnium for use as a thin-film capacitor has been examined by the current-voltage characteristics of the anodization and the in-depth analysis of formed oxide using Auger electron spectroscopy. It is found that the oxide growth obeys three different rate laws such as the linear rate law at first and next the parabolic rate law during the constant current anodization, and then the reciprocal logarithmic rate law during the constant voltage anodization following after the constant current process. From the Auger electron spectroscopy analysis, it is found that the shape of the compositional depth profile of the grown oxide film varies associating with the rate law of oxidation obeyed. The variation of depth profile correlating with the rate law is discussed with respect to each elementary process such as the transport and/or the reaction of chemical species interpreted from the over-all behavior of anodization process. It is revealed that the stoichiometric film having an interface with sharp transition, which is favorable for obtaining excellent electrical properties of the capacitor, can be obtained under the condition that the phase-boundary reaction is the rate-determining step of the anodization. The constant voltage anodization process also satisfies such circumstances and therefore can be favorable method for preparing highquality thin-film capacitors. (author)

  16. Evaluation and Enhancement of the Oxygen Reduction Reaction Activity on Hafnium Oxide Nanoparticles Assisted by L(+)-lysine

    International Nuclear Information System (INIS)

    Chisaka, Mitsuharu; Itagaki, Noriaki

    2016-01-01

    Evaluation of the oxygen reduction reaction (ORR) on oxide compounds is difficult owing to the insulating nature of oxides. In this study, various amounts of L(+)-lysine were added to the precursor dispersion for the hydrothermal synthesis of hafnium oxide nanoparticles on reduced graphene oxide sheets (HfO_x–rGO) to coat the HfO_x catalysts with layers of carbon, thereby increasing the conductivity and number of active sites. When the mass ratio of L(+)-lysine to GO, R, was above 26, carbon layers were formed and the amount monotonically increased with increasing R, as noted by cyclic voltammogrametry. X-ray photoelectron spectroscopy and rotating disk electrode analyses revealed that pyrolysis produced ORR-active oxygen defects, whose formation was proposed to involve carbothermal reduction. When 53 ≤ R ≤ 210, HfO_x–rGO contained a similar amount of oxygen defects and ORR activity, as represented by an onset potential of 0.9 V versus the reversible hydrogen electrode in 0.1 mol dm"−"3 H_2SO_4. However, the number of active sites depended on R due to the amount of L(+)-lysine-derived carbon layers that increased both the number of active sites and resistivity towards oxygen diffusion.

  17. IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zywiec, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-01-11

    This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012, demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.

  18. Trap state passivation improved hot-carrier instability by zirconium-doping in hafnium oxide in a nanoscale n-metal-oxide semiconductor-field effect transistors with high-k/metal gate

    International Nuclear Information System (INIS)

    Liu, Hsi-Wen; Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Chang, Ting-Chang; Chen, Ching-En; Tseng, Tseung-Yuen; Lin, Chien-Yu; Cheng, Osbert; Huang, Cheng-Tung; Ye, Yi-Han

    2016-01-01

    This work investigates the effect on hot carrier degradation (HCD) of doping zirconium into the hafnium oxide high-k layer in the nanoscale high-k/metal gate n-channel metal-oxide-semiconductor field-effect-transistors. Previous n-metal-oxide semiconductor-field effect transistor studies demonstrated that zirconium-doped hafnium oxide reduces charge trapping and improves positive bias temperature instability. In this work, a clear reduction in HCD is observed with zirconium-doped hafnium oxide because channel hot electron (CHE) trapping in pre-existing high-k bulk defects is the main degradation mechanism. However, this reduced HCD became ineffective at ultra-low temperature, since CHE traps in the deeper bulk defects at ultra-low temperature, while zirconium-doping only passivates shallow bulk defects.

  19. [The electron microscopic observation of the effect of monoclonal antibody on the form and structure of mutans streptococci OMZ176].

    Science.gov (United States)

    Wen, L; Yue, S

    1996-01-01

    The effect of monoclonal antibody on the form and structure of Mutans Streptococci OMZ176 was studied. The result showed that a great number of Mutans Streptococci OMZ176 was agglutianated after treating with monoclonal antibody prepared by a cell wall protein antigen (molecular weight 220 kd) of Mutans Streptococci OMZ176. Bacterial cells were swollen obviously. The gap between cell wall and cytoplasmic was widened. The electronic density of cell plasm was greatly decreased.

  20. George de Hevesy (1885-1966). Discoverer of hafnium, founder of radioanalytical chemistry and X-ray fluorescence analysis and father of nuclear medicine

    International Nuclear Information System (INIS)

    Niese, Siegfried

    2017-01-01

    George de Hevesy known as discoverer of hafnium, founder of radioanalytical chemistry and X-ray fluorescence analysis and father of nuclear medicine has done important research work in inorganic, physical and radioanalytical and physiological chemistry as well as in geochemistry, radiation biology and medicine. When he must flee for political reasons from a country he must change his colleagues, his equipments, and the topic of his work. It is extremely surprising that he could receive important results under such circumstances even at an advanced age. (author)

  1. A spanish mineral of zirconium and hafnium. Separation of the two elements by liquid-liquid extraction, using tributyl phosphate as chelating agent

    International Nuclear Information System (INIS)

    Ruiz Sanchez, F.; Cruz Castillo, F. de la; Fernandez Cellini, R.

    1962-01-01

    The zirconium and Hafnium oxides are obtained from a Spanish mineral of zircon with an average contest of 55% in ZrO 2 -HfO 2 . An alkaline fusion to open the mineral, followed by a purification by crystallization as (Zr O-Hf O)Cl 2 H 2 O or as (Zr-Hf) (SO 4 ) 2 . 4H 2 O, is used. A discussion of the best experimental conditions for opening the mineral and of the purification method is made. (Author) 45 refs

  2. 46 CFR 176.710 - Inspection and testing prior to hot work.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Inspection and testing prior to hot work. 176.710... testing prior to hot work. (a) An inspection for flammable or combustible gases must be conducted by a... operations involving riveting, welding, burning, or other fire producing actions may be made aboard a vessel...

  3. 46 CFR 176.660 - Continued participation in the Alternative Hull Examination (AHE) Program.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Continued participation in the Alternative Hull... (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.660 Continued participation in the Alternative Hull Examination (AHE) Program. (a) To...

  4. 46 CFR 176.630 - The Alternative Hull Examination (AHE) Program application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false The Alternative Hull Examination (AHE) Program... PASSENGER VESSELS (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.630 The Alternative Hull Examination (AHE) Program application. If your vessel meets the eligibility...

  5. 46 CFR 176.650 - Alternative Hull Examination Program options: Divers or underwater ROV.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Alternative Hull Examination Program options: Divers or...) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.650 Alternative Hull Examination Program options: Divers or underwater ROV. To complete the...

  6. 19 CFR 176.11 - Transmission of records to Court of International Trade.

    Science.gov (United States)

    2010-04-01

    ... SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) PROCEEDINGS IN THE COURT OF INTERNATIONAL TRADE Transmission of Records § 176.11 Transmission of records to Court of International Trade. Upon receipt of service of a summons in an action initiated in the Court of International Trade the following items shall...

  7. 30 CFR 206.176 - How do I perform accounting for comparison?

    Science.gov (United States)

    2010-07-01

    ... paragraphs (b) and (c) of this section, the actual dual accounting value, for royalty purposes, is the... 30 Mineral Resources 2 2010-07-01 2010-07-01 false How do I perform accounting for comparison? 206... REVENUE MANAGEMENT PRODUCT VALUATION Indian Gas § 206.176 How do I perform accounting for comparison? (a...

  8. 49 CFR 176.93 - Vehicles having refrigerating or heating equipment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Vehicles having refrigerating or heating equipment... Transported on Board Ferry Vessels § 176.93 Vehicles having refrigerating or heating equipment. (a) A transport vehicle fitted with refrigerating or heating equipment using a flammable liquid or Division 2.1...

  9. 49 CFR 176.76 - Transport vehicles, freight containers, and portable tanks containing hazardous materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Transport vehicles, freight containers, and... TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY VESSEL General Handling and Stowage § 176.76 Transport... paragraphs (b) through (f) of this section, hazardous materials authorized to be transported by vessel may be...

  10. 49 CFR 176.170 - Transport of Class 1 (explosive) materials in freight containers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Transport of Class 1 (explosive) materials in... REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Cargo Transport Units and Shipborne Barges § 176.170 Transport of Class 1 (explosive) materials in freight containers. (a...

  11. 49 CFR 176.174 - Transport of Class 1 (explosive) materials in shipborne barges.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Transport of Class 1 (explosive) materials in... REGULATIONS CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Cargo Transport Units and Shipborne Barges § 176.174 Transport of Class 1 (explosive) materials in shipborne barges. (a...

  12. 49 CFR 176.903 - Stowage of cotton or vegetable fibers with coal.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Stowage of cotton or vegetable fibers with coal... § 176.903 Stowage of cotton or vegetable fibers with coal. Cotton or vegetable fibers being transported on a vessel may not be stowed in the same hold with coal. They may be stowed in adjacent holds if the...

  13. 12 CFR 563.176 - Interest-rate-risk-management procedures.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Interest-rate-risk-management procedures. 563... ASSOCIATIONS-OPERATIONS Financial Management Policies § 563.176 Interest-rate-risk-management procedures... association's management of that risk. (b) The board of directors shall formerly adopt a policy for the...

  14. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Science.gov (United States)

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more than...

  15. 49 CFR 176.108 - Supervision of Class 1 (explosive) materials during loading, unloading, handling and stowage.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Supervision of Class 1 (explosive) materials during loading, unloading, handling and stowage. 176.108 Section 176.108 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS...

  16. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    International Nuclear Information System (INIS)

    Rezaei, B.; Meghdadi, S.; Zarandi, R. Fazel

    2008-01-01

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf 4+ (Hafnium(IV)) over a wide concentration range (2.0 x 10 -7 to 1.0 x 10 -1 M) with the determination coefficient of 0.9966 and slope of 15.1 ± 0.1 mV decades -1 . The limit of detection is 1.9 x 10 -7 M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf 4+ ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf 4+ in solutions by standard addition method for real sample analysis

  17. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, B. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Meghdadi, S.; Zarandi, R. Fazel [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2008-08-30

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf{sup 4+} (Hafnium(IV)) over a wide concentration range (2.0 x 10{sup -7} to 1.0 x 10{sup -1} M) with the determination coefficient of 0.9966 and slope of 15.1 {+-} 0.1 mV decades{sup -1}. The limit of detection is 1.9 x 10{sup -7} M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf{sup 4+} ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf{sup 4+} in solutions by standard addition method for real sample analysis.

  18. Fission fragment angular distribution in the reaction 28Si+176Yb

    International Nuclear Information System (INIS)

    Tripathi, R.; Sudarshan, K.; Sharma, S.K.; Reddy, A.V.R.; Pujari, P.K.; Dutta, D.; Goswami, A.; Ramachandran, K.

    2009-01-01

    Fission fragment angular distribution has been measured in the reaction 28 Si+ 176 Yb at beam energies of 145 and 155 MeV to investigate the contribution from non-compound nucleus fission. Experiments were carried out at BARC-TIFR Pelletron-LINAC accelerator facility, Mumbai. Experimental angular anisotropies in this reaction were observed to be higher than those calculated using statistical theory, indicating contribution from non-compound nucleus fission in this reaction. (author)

  19. Phylogenetic analysis of the MS4A and TMEM176 gene families.

    Directory of Open Access Journals (Sweden)

    Jonathan Zuccolo

    2010-02-01

    Full Text Available The MS4A gene family in humans includes CD20 (MS4A1, FcRbeta (MS4A2, Htm4 (MS4A3, and at least 13 other syntenic genes encoding membrane proteins, most having characteristic tetraspanning topology. Expression of MS4A genes is variable in tissues throughout the body; however, several are limited to cells in the hematopoietic system where they have known roles in immune cell functions. Genes in the small TMEM176 group share significant sequence similarity with MS4A genes and there is evidence of immune function of at least one of the encoded proteins. In this study, we examined the evolutionary history of the MS4A/TMEM176 families as well as tissue expression of the phylogenetically earliest members, in order to investigate their possible origins in immune cells.Orthologs of human MS4A genes were found only in mammals; however, MS4A gene homologs were found in most jawed vertebrates. TMEM176 genes were found only in mammals and bony fish. Several unusual MS4A genes having 2 or more tandem MS4A sequences were identified in the chicken (Gallus gallus and early mammals (opossum, Monodelphis domestica and platypus, Ornithorhyncus anatinus. A large number of highly conserved MS4A and TMEM176 genes was found in zebrafish (Danio rerio. The most primitive organism identified to have MS4A genes was spiny dogfish (Squalus acanthus. Tissue expression of MS4A genes in S. acanthias and D. rerio showed no evidence of expression restricted to the hematopoietic system.Our findings suggest that MS4A genes first appeared in cartilaginous fish with expression outside of the immune system, and have since diversified in many species into their modern forms with expression and function in both immune and nonimmune cells.

  20. Phylogenetic Analysis of the MS4A and TMEM176 Gene Families

    Science.gov (United States)

    Zuccolo, Jonathan; Bau, Jeremy; Childs, Sarah J.; Goss, Greg G.; Sensen, Christoph W.; Deans, Julie P.

    2010-01-01

    Background The MS4A gene family in humans includes CD20 (MS4A1), FcRβ (MS4A2), Htm4 (MS4A3), and at least 13 other syntenic genes encoding membrane proteins, most having characteristic tetraspanning topology. Expression of MS4A genes is variable in tissues throughout the body; however, several are limited to cells in the hematopoietic system where they have known roles in immune cell functions. Genes in the small TMEM176 group share significant sequence similarity with MS4A genes and there is evidence of immune function of at least one of the encoded proteins. In this study, we examined the evolutionary history of the MS4A/TMEM176 families as well as tissue expression of the phylogenetically earliest members, in order to investigate their possible origins in immune cells. Principal Findings Orthologs of human MS4A genes were found only in mammals; however, MS4A gene homologs were found in most jawed vertebrates. TMEM176 genes were found only in mammals and bony fish. Several unusual MS4A genes having 2 or more tandem MS4A sequences were identified in the chicken (Gallus gallus) and early mammals (opossum, Monodelphis domestica and platypus, Ornithorhyncus anatinus). A large number of highly conserved MS4A and TMEM176 genes was found in zebrafish (Danio rerio). The most primitive organism identified to have MS4A genes was spiny dogfish (Squalus acanthus). Tissue expression of MS4A genes in S. acanthias and D. rerio showed no evidence of expression restricted to the hematopoietic system. Conclusions/Significance Our findings suggest that MS4A genes first appeared in cartilaginous fish with expression outside of the immune system, and have since diversified in many species into their modern forms with expression and function in both immune and nonimmune cells. PMID:20186339

  1. Four-quasiparticle isomers and K-forbidden transitions in 176Lu

    International Nuclear Information System (INIS)

    McGoram, T.R.; Dracoulis, G.D.; Kibedi, T.; Mullins, M.; Byrne, A.P.; Baxter, A.M.

    2000-01-01

    Full text: The odd-odd nucleus 176 Lu has been the subject of extensive experimental and theoretical investigation over the last forty years. Much of this interest has stemmed from the role of 176 Lu in the s-process in nucleosynthesis. From a nuclear structure perspective, 176 Lu resides in a region of the nuclear chart where collective rotation and high-K, multi-quasiparticle states compete to form the yrast line (the locus of state with the lowest energy at a given angular momentum). The electromagnetic decay of intermediate and high-K states is often hindered due to the K-selection rule, while apparent violations of this selection rule have been ascribed to Coriolis mixing, shape changes in the gamma-degree of freedom, and so-called 'statistical' mixing. The relative importance of these mechanisms remains an open question. We present here the results of gamma-ray and conversion-electron spectroscopic measurements, performed at the Heavy Ion Facility at the Australian National University in Canberra, using the reaction 176 Yb( 7 Li, α3n) at a beam energy of 45 MeV. Two new four-quasiparticle isomers have been established, with mean lives of 400(100)ns and 58(5)μs, and spin projections and parities of 12 + and (14 + ) respectively. The shorter--lived isomer displays both normal and anomalous K-forbidden decays, which we show is the result of two-state mixing between the isomeric state and a member of a two-quasiparticle rotational band. The implied mixing matrix element of only 5 eV shows explicitly that very small mixing matrix elements may be responsible for anomalous K-hindered decays

  2. Activation of catalase activity by a peroxisome-localized small heat shock protein Hsp17.6CII.

    Science.gov (United States)

    Li, Guannan; Li, Jing; Hao, Rong; Guo, Yan

    2017-08-20

    Plant catalases are important antioxidant enzymes and are indispensable for plant to cope with adverse environmental stresses. However, little is known how catalase activity is regulated especially at an organelle level. In this study, we identified that small heat shock protein Hsp17.6CII (AT5G12020) interacts with and activates catalases in the peroxisome of Arabidopsis thaliana. Although Hsp17.6CII is classified into the cytosol-located small heat shock protein subfamily, we found that Hsp17.6CII is located in the peroxisome. Moreover, Hsp17.6CII contains a novel non-canonical peroxisome targeting signal 1 (PTS1), QKL, 16 amino acids upstream from the C-terminus. The QKL signal peptide can partially locate GFP to peroxisome, and mutations in the tripeptide lead to the abolishment of this activity. In vitro catalase activity assay and holdase activity assay showed that Hsp17.6CII increases CAT2 activity and prevents it from thermal aggregation. These results indicate that Hsp17.6CII is a peroxisome-localized catalase chaperone. Overexpression of Hsp17.6CII conferred enhanced catalase activity and tolerance to abiotic stresses in Arabidopsis. Interestingly, overexpression of Hsp17.6CII in catalase-deficient mutants, nca1-3 and cat2 cat3, failed to rescue their stress-sensitive phenotypes and catalase activity, suggesting that Hsp17.6CII-mediated stress response is dependent on NCA1 and catalase activity. Overall, we identified a novel peroxisome-located catalase chaperone that is involved in plant abiotic stress resistance by activating catalase activity. Copyright © 2017 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

  3. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    Science.gov (United States)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  4. Static quadrupole moment of the Kπ = 14+ isomer in 176W

    International Nuclear Information System (INIS)

    Ionescu-Bujor, M.; Iordachescu, A.; Bucurescu, D.; Brandolini, F.; Lenzi, S. M.; Pavan, P.; Rossi Alvarez, C.; Marginean, N.; Medina, N.H.; Ribas, R.V.; De Poli, M.; Napoli, D. R.; Podolyak, Zs.; Ur, C. A.

    2001-01-01

    The investigation of high-K isomeric states in the deformed nuclei of the A∼180 region has found renewed interest in recent years. Much experimental and theoretical work was devoted to understand the mechanisms which govern their decay to lower-lying states, particularly the anomalous strong decays to low-K states. Other questions of great importance are the quenching of the pairing correlations and the shape polarization effects in the high-seniority multi-quasiparticle excitations. Our interest focused on the 41 ns K π =14 + 3746 keV isomeric state with anomalous decay in 176 W. On the basis of a precise g-factor measurement we assigned to this isomer a pure four-quasiparticle configuration, composed by two protons in the 7/2 + [404] and 9/2 - [514] orbitals and two neutrons in the 7/2 + [633] and 5/2 - [512] orbitals. In the present work the measurement of its static quadrupole moment has been performed. Prior to our experiment, static quadrupole moments have been measured only for three high-K isomeric states of seniority ≥ 4 in the A∼180 region: 16 + in 178 Hf, 35/2 - in 179 W and 25 + in 182 Os. A deformation very similar to that of the ground state has been deduced for the 16 + isomer in 178 Hf, while for the high-K isomers in 179 W and 182 Os significantly smaller deformations were reported. The quadrupole interaction of the 14 + isomeric state in 176 W has been investigated in the electric field gradient (EFG) of the polycrystalline lattice of metallic Tl by applying the time-differential perturbed angular distribution method. For W impurities in Tl host the EFG strength and its temperature dependence have been recently reported. The isomer was populated in the 164 Dy( 16 O,4n) 176 W reaction using a 83 MeV 16 O pulsed beam (pulse width 1.5 ns, repetition period 800 ns) delivered by the XTU-Tandem of Laboratori Nazionali di Legnaro. The target consisted of 0.5 mg/cm 2 metallic 164 Dy on thick Tl backing in which both the recoiling 176 W nuclei and

  5. g-factor of the Kπ = 14+ isomer in 176 W

    International Nuclear Information System (INIS)

    Ionescu-Bujor, M.; Iordachescu, A.; Marginean, N.; Brandolini, F.; Pavan, P.; Lenzi, S.M.; De Poli, M.; Gadea, A.; Martinez, T.; Medina, N.H.; Ribas, R.V.; Podolyak, Zs.

    2000-01-01

    In the deformed A ≅ 180 nuclei with β 2 ≅ 0.25 multi-quasiparticle intrinsic states are able to compete with rotational structures as both proton and neutron Fermi surfaces are close to nucleon orbits with large projections Ω on the prolate symmetry axis. Due to the approximate conservation of the K quantum number, these states often have hindered decays with half-lives ranging from nanoseconds to years. The decay characteristics of the high-K isomers, as well as the properties of the collective bands built on them, were subject of detailed experimental studies over the last decade. Particular attention has been devoted to the apparent breakdown of the K-selection rule observed experimentally in the decay of several high-spin isomeric states of the A ≅ 180 region. A very interesting high-K isomer showing in its decay a severe violation of the K-selection rule has been recently found in 176 W. The isomeric state, with K π = 14 + , T 1/2 = 35(10) ns and E x =3746 keV, de-excites predominantly to states with K=0, bypassing available levels of intermediate K. To elucidate the isomer underlying structure, an experiment to determine its the g-factor has been performed at the LNL XTU-tandem, by applying the time-differential perturbed angular distribution (TDPAD) method in an external magnetic field. The isomer was populated in the 164 Dy( 16 O,4n) 176 W reaction at a bombarding energy of 83 MeV. The 16 O beam has been pulsed with a pulse width of 1.5 ns at a repetition period of 800 ns. In view of the very low isomer population (about 2% of the 4n channel), a high suppression of the continuous beam in-between the beam bursts was necessary for a proper observation of the isomeric decay γ-lines. The target consisted of 0.5 mg/cm 2 metallic 164 Dy on thick Pb backing in which both the recoiling 176 W nuclei and the projectiles were stopped. Two planar Ge detectors and two Ge detectors of 25% efficiency placed at the angles ± 135 angle and ± 45 angle with respect

  6. PET attenuation correction for rigid MR Tx/Rx coils from 176Lu background activity

    Science.gov (United States)

    Lerche, Christoph W.; Kaltsas, Theodoris; Caldeira, Liliana; Scheins, Jürgen; Rota Kops, Elena; Tellmann, Lutz; Pietrzyk, Uwe; Herzog, Hans; Shah, N. Jon

    2018-02-01

    One challenge for PET-MR hybrid imaging is the correction for attenuation of the 511 keV annihilation radiation by the required RF transmit and/or RF receive coils. Although there are strategies for building PET transparent Tx/Rx coils, such optimised coils still cause significant attenuation of the annihilation radiation leading to artefacts and biases in the reconstructed activity concentrations. We present a straightforward method to measure the attenuation of Tx/Rx coils in simultaneous MR-PET imaging based on the natural 176Lu background contained in the scintillator of the PET detector without the requirement of an external CT scanner or PET scanner with transmission source. The method was evaluated on a prototype 3T MR-BrainPET produced by Siemens Healthcare GmbH, both with phantom studies and with true emission images from patient/volunteer examinations. Furthermore, the count rate stability of the PET scanner and the x-ray properties of the Tx/Rx head coil were investigated. Even without energy extrapolation from the two dominant γ energies of 176Lu to 511 keV, the presented method for attenuation correction, based on the measurement of 176Lu background attenuation, shows slightly better performance than the coil attenuation correction currently used. The coil attenuation correction currently used is based on an external transmission scan with rotating 68Ge sources acquired on a Siemens ECAT HR  +  PET scanner. However, the main advantage of the presented approach is its straightforwardness and ready availability without the need for additional accessories.

  7. STELLAR ACTIVITY AND ITS IMPLICATIONS FOR EXOPLANET DETECTION ON GJ 176

    International Nuclear Information System (INIS)

    Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Henry, Gregory W.; Williamson, Michael H.

    2015-01-01

    We present an in-depth analysis of stellar activity and its effects on radial velocity (RV) for the M2 dwarf GJ 176 based on spectra taken over 10 yr from the High Resolution Spectrograph on the Hobby-Eberly Telescope. These data are supplemented with spectra from previous observations with the HIRES and HARPS spectrographs, and V- and R-band photometry taken over six years at the Dyer and Fairborn observatories. Previous studies of GJ 176 revealed a super-Earth exoplanet in an 8.8-day orbit. However, the velocities of this star are also known to be contaminated by activity, particularly at the 39-day stellar rotation period. We have examined the magnetic activity of GJ 176 using the sodium I D lines, which have been shown to be a sensitive activity tracer in cool stars. In addition to rotational modulation, we see evidence of a long-term trend in our Na I D index, which may be part of a long-period activity cycle. The sodium index is well correlated with our RVs, and we show that this activity trend drives a corresponding slope in RV. Interestingly, the rotation signal remains in phase in photometry, but not in the spectral activity indicators. We interpret this phenomenon as the result of one or more large spot complexes or active regions which dominate the photometric variability, while the spectral indices are driven by the overall magnetic activity across the stellar surface. In light of these results, we discuss the potential for correcting activity signals in the RVs of M dwarfs

  8. Discinesias induzidas por levodopa em 176 pacientes com doença de Parkinson Levodopa-induced dyskinesias in 176 parkisonian patients

    Directory of Open Access Journals (Sweden)

    Maria Sheila G. Rocha

    1995-12-01

    Full Text Available A ocorrência de discinesias dificulta consideravelmente o manuseio terapêutico dos pacientes parkinsonianos tratados com levodopa. Estudamos as características clínicas das discinesias em 176 pacientes com diagnóstico de doença de Parkinson e tratados com levodopa. As discinesias ocorreram, em média, após 6,2 anos de duração da doença e após 4,2 anos de tratamento com levodopa. A maioria dos pacientes (90% achava-se nos estágios II e III de Hoehn & Yahr por ocasião do início das discinesias. As discinesias mais frequentes foram as de "pico de dose" e "contínua". Movimento do tipo distônico ocorreu em 40% dos casos e predominou nas discinesias de "fim de dose" e "bifásica". Distonia matinal correspondeu a 35% dos casos de distonia. Movimentos coreiformes se manifestaram de forma generalizada em 43,2% dos casos. Movimentos distônicos predominaram nos membros inferiores. A discinesia, quando unilateral, ocorreu mais frequüentemente no hemicorpo mais comprometido pela doença de Parkinson. A discinesia orofacial, quando isolada, foi mais frequente nos pacientes mais idosos.Dyskinesias are frequently observed in parkinsonian patients during levodopa treatment. The occurrence of these movement disorders usually makes the therapeutic management of the patients very difficult. The clinical characteristics of 176 patients with dyskinesias were retrospectively studied. Dyskinesias occurred, on average, after 6,2 years of duration of Parkinson's disease and after 4.2 years on treatment with levodopa. Patients were more likely to have dyskinesias during more advanced stages (measured by Hoehn and Yahr scale. Peak of dose and square wave were the types of dyskinesia more frequently described and were associated with choreic movements in most cases. Dystonia occurred in 40% of the cases and was predominant in end of dose and diphasic dyskinesias. Thirty-five percent of dystonia cases presented as "early morning dystonia". Chorea was the

  9. Isomeric ratio measurements for the radiative neutron capture 176Lu(n,γ at DANCE

    Directory of Open Access Journals (Sweden)

    Denis-Petit D.

    2017-01-01

    Full Text Available The isomeric ratios for the neutron capture reaction 176Lu(n,γ to the Jπ = 5/2−, 761.7 keV, T1/2 = 32.8 ns and the Jπ = 15/2+, 1356.9 keV, T1/2 = 11.1 ns levels of 177Lu, have been measured for the first time with the Detector for Advanced Neutron Capture Experiments (DANCE at the Los Alamos National Laboratory. These measured isomeric ratios are compared with TALYS calculations.

  10. Kaznivo dejanje prikazovanja, izdelave, posesti in posredovanja pornografskega gradiva (176. člen KZ-1)

    OpenAIRE

    Jeran, Ana

    2017-01-01

    Analiza 176. člena slovenskega kazenskega zakonika je pokazala, kako zapleteno je vprašanje prepovedi soočenja otrok s pornografskim gradivom in kako nujno potrebna je primerna inkriminacija otroške pornografije zaradi vse bolj razširjenega in dostopnega interneta. Gre za najhitreje rastoči internetni trg, zato je za boj proti tovrstnemu kriminalu potrebno sodelovanje na mednarodni ravni, ki se odraža v številnih mednarodnopravno sprejetih aktih, ki obravnavajo to materijo. Glavni cilj inkrim...

  11. PRODUCTION OF HAFNIUM METAL

    Science.gov (United States)

    Elger, G.W.; Boubel, R.W.

    1963-01-01

    This patent deals with a process of producing pure Hf metal from oxygen- contaminated gaseous Hf chloride. The oxygen compounds in the chioride gas are halogenated by contacting the gas at elevated temperature with Cl/sub 2/ in the presence of C. The Hf chloride, still in gaseous form, is contacted with molten Mg whereby Hf metal is formed and condensed on the Mg. (AEC)

  12. Effects of oxygen partial pressure and annealing temperature on the residual stress of hafnium oxide thin-films on silicon using synchrotron-based grazing incidence X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Debaleen [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Sinha, Anil Kumar [ISU, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India); Homi Bhabha National Institute, BARC, Mumbai 400 094 (India); Chakraborty, Supratic, E-mail: supratic.chakraborty@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

    2016-10-30

    Highlights: • Residual stress estimation thin hafnium oxide film with thickness of <10 nm. • A mathematical expression is proposed for stress estimation of thin-film using GIXRD. • Residual stress varies with argon content in Ar/O{sub 2} plasma and annealing temperature. • Variation of stress is explained by IL swelling and enhanced structural relaxation. - Abstract: Synchrotron radiation-based grazing incidence X-ray diffraction (GI-XRD) technique is employed here to estimate the residual stress of < 10 nm thin hafnium oxide film deposited on Si (100) substrate at different argon/oxygen ratios using reactive rf sputtering. A decrease in residual stress, tensile in nature, is observed at higher annealing temperature for the samples deposited with increasing argon ratio in the Ar/O{sub 2} plasma. The residual stress of the films deposited at higher p{sub Ar} (Ar:O{sub 2} = 4:1) is also found to be decreased with increasing annealing temperature. But the stress is more or less constant with annealing temperature for the films deposited at lower Ar/O{sub 2} (1:4) ratio. All the above phenomena can be explained on the basis of swelling of the interfacial layer and enhanced structural relaxation in the presence of excess Hf in hafnium oxide film during deposition.

  13. High-K isomers in {sup 176}W and mechanisms of K-violation

    Energy Technology Data Exchange (ETDEWEB)

    Crowell, B.; Janssens, R.V.F.; Blumenthal, D.J. [and others

    1995-08-01

    K-isomers are states in deformed nuclei whose {gamma}-decay is hindered by selection rules involving K, the projection of the angular momentum along the axis of symmetry of the nucleus. Previous work with the Argonne Notre Dame BGO Array delineated the existence of two K-isomers in {sup 176}W, one of which had a very unusual pattern of decay. A short description of this work was published as a letter, and a more complete account is being readied for submission. These results provided evidence that quantum-mechanical fluctuations in the nuclear shape may be responsible for some of the observed K-violating transitions. In addition, hints were present in the data of the existence of another K-isomer with an even higher in. An experiment was performed in September 1994 to observe this isomer, using the reaction {sup 50}Ti({sup 130}Te,4n), and a technique in which recoiling {sup 176}W nuclei were created 17-cm upstream of the center of the array and caught on a Pb catcher foil at the center. Intense ({approximately} 3 pnA) beams of {sup 130}Te were supplied by the ECR source using a new sputtering technique. The recoil-shadow geometry was highly successful at removing the background from non-isomeric decays, allowing the weakly populated K-isomers to be detected cleanly. In addition, the availability of pulsed beams from ATLAS and the timing data from the BGO array provided a second technique for isolating the decays of interest, by selecting events in which a given number of BGO detectors fired between beam pulses. This method was used in the previous experiment, and was also applied in this experiment as a second level of selection. As a result, gamma-ray transitions were detected in the present experiment with intensities as small as {approximately} 0.02 % of the {sup 176}W reaction channel. The existence of the new isomer was confirmed, and a partial level-scheme was constructed.

  14. Physical Properties of Main-belt Comet 176P/LINEAR

    Science.gov (United States)

    Hsieh, Henry H.; Ishiguro, Masateru; Lacerda, Pedro; Jewitt, David

    2011-07-01

    We present a physical characterization of comet 176P/LINEAR, the third discovered member of the new class of main-belt comets, which exhibit cometary activity but are dynamically indistinguishable from main-belt asteroids. Observations show the object exhibiting a fan-shaped tail for at least one month in late 2005, but then becoming inactive in early 2006. During this active period, we measure broadband colors of B - V = 0.63 ± 0.02, V - R = 0.35 ± 0.02, and R - I = 0.31 ± 0.04. Using data from when the object was observed to be inactive, we derive best-fit IAU phase function parameters of H = 15.10 ± 0.05 mag and G = 0.15 ± 0.10, and best-fit linear phase function parameters of m(1, 1, 0) = 15.35 ± 0.05 mag and β = 0.038 ± 0.005 mag deg-1. From this baseline phase function, we find that 176P exhibits a mean photometric excess of ~30% during its active period, implying an approximate total coma dust mass of Md ~ (7.2 ± 3.6) × 104 kg. From inactive data obtained in early 2007, we find a rotation period of P rot = 22.23 ± 0.01 hr and a peak-to-trough photometric range of Δm ~ 0.7 mag. Phasing our photometric data from 176P's 2005 active period to this rotation period, we find that the nucleus exhibits a significantly smaller photometric range than in 2007 that cannot be accounted for by coma damping effects, and as such, are attributed by us to viewing geometry effects. A detailed analysis of these geometric effects showed that 176P is likely to be a highly elongated object with an axis ratio of 1.8 data presented herein were obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership. Additionally, some of the presented data were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National

  15. Fission fragment mass distribution in the 13C+182W and 176Yb reactions

    International Nuclear Information System (INIS)

    Ramachandran, K.; Hinde, D.J.; Dasgupta, M.; Williams, E.; Wakhle, A.; Luong, D.H.; Evers, M.; Carter, I.P.; Das, S.

    2014-01-01

    Fission fragment mass distributions have been measured for many systems and found to be asymmetric in the fission of nuclei with nucleon number A in the range 228-258 and proton number Z in the range 90-100. For lighter systems, it has been observed that fission fragment mass distributions are usually symmetric. At high excitation energies the shell effects are expected to vanish and the nuclei are expected to behave like a charged liquid drop; hence, only symmetric fission is expected for all the nuclei. Even after much experimental and theoretical work in this field, the rate of damping of shell effects with excitation energy is not well known. This abstract reports our measurements with 13 C beams on 182 W and 176 Yb targets

  16. Contribution towards ALD and MOCVD of rare earth oxides and hafnium oxide. From precursor evaluation to process development and thin film characterization

    International Nuclear Information System (INIS)

    Xu, Ke

    2013-01-01

    elements for ALD applications. A possible synthesis route is the salt metatheses route. It could be expected that the monodentate guanidine ligand would provide increased reactivity towards water, where the bulky guanidine ligands will shield the RE center providing self-limiting growth behavior. In Chapter 4 and 7, ALD of rare earth oxides and hafnium oxide using corresponding guanidinate precursors are in detail investigated. According to the measurements, these processes are true ALD processes with broad ALD windows, high growth per cycle in the saturated area. Furthermore, the rare earth guanidinate and hafnium guanidinate precursors exhibit matching ALD window in the temperature range of 200 - 225 C. This motivated us to deposite trinary oxide thin films (HfREOx) using corresponding precursor combinations.

  17. Effect of Advanced Plasma Source bias voltage on properties of HfO2 films prepared by plasma ion assisted electron evaporation from metal hafnium

    International Nuclear Information System (INIS)

    Zhu, Meiping; Yi, Kui; Arhilger, Detlef; Qi, Hongji; Shao, Jianda

    2013-01-01

    HfO 2 films, using metal hafnium as starting material, are deposited by plasma-ion assisted electron evaporation with different Advanced Plasma Source (APS) bias voltages. The refractive index and extinction coefficient are calculated, the chemical state and composition, as well as the stress and aging behavior is investigated. Laser induced damage threshold (LIDT) and damage mechanism are also evaluated and discussed. Optical, structural, mechanical and laser induced damage properties of HfO 2 films are found to be sensitive to APS bias voltage. The film stress can be tuned by varying the APS bias voltage. Damage morphologies indicate the LIDT of the HfO 2 films at 1064 nm and 532 nm are dominated by the nodular-defect density in coatings, while the 355 nm LIDT is dominated by the film absorption. HfO 2 films with higher 1064 nm LIDT than samples evaporated from hafnia are achieved with bias voltage of 100 V. - Highlights: • HfO 2 films are evaporated with different Advanced Plasma Source (APS) bias voltages. • Properties of HfO 2 films are sensitive to APS bias voltage. • With a bias voltage of 100 V, HfO 2 coatings without any stress can be achieved. • Higher 1064 nm laser induced damage threshold is achieved at a bias voltage of 100 V

  18. Design of an Extractive Distillation Column for the Environmentally Benign Separation of Zirconium and Hafnium Tetrachloride for Nuclear Power Reactor Applications

    Directory of Open Access Journals (Sweden)

    Le Quang Minh

    2015-09-01

    Full Text Available Nuclear power with strengthened safety regulations continues to be used as an important resource in the world for managing atmospheric greenhouse gases and associated climate change. This study examined the environmentally benign separation of zirconium tetrachloride (ZrCl4 and hafnium tetrachloride (HfCl4 for nuclear power reactor applications through extractive distillation using a NaCl-KCl molten salt mixture. The vapor–liquid equilibrium behavior of ZrCl4 and HfCl4 over the molten salt system was correlated with Raoult’s law. The molten salt-based extractive distillation column was designed optimally using a rigorous commercial simulator for the feasible separation of ZrCl4 and HfCl4. The molten salt-based extractive distillation approach has many potential advantages for the commercial separation of ZrCl4 and HfCl4 compared to the conventional distillation because of its milder temperatures and pressure conditions, smaller number of required separation trays in the column, and lower energy requirement for separation, while still taking the advantage of environmentally benign feature by distillation. A heat-pump-assisted configuration was also explored to improve the energy efficiency of the extractive distillation process. The proposed enhanced configuration reduced the energy requirement drastically. Extractive distillation can be a promising option competing with the existing extraction-based separation process for zirconium purification for nuclear power reactor applications.

  19. A silicon doped hafnium oxide ferroelectric p–n–p–n SOI tunneling field–effect transistor with steep subthreshold slope and high switching state current ratio

    Directory of Open Access Journals (Sweden)

    Saeid Marjani

    2016-09-01

    Full Text Available In this paper, a silicon–on–insulator (SOI p–n–p–n tunneling field–effect transistor (TFET with a silicon doped hafnium oxide (Si:HfO2 ferroelectric gate stack is proposed and investigated via 2D device simulation with a calibrated nonlocal band–to–band tunneling model. Utilization of Si:HfO2 instead of conventional perovskite ferroelectrics such as lead zirconium titanate (PbZrTiO3 and strontium bismuth tantalate (SrBi2Ta2O9 provides compatibility to the CMOS process as well as improved device scalability. By using Si:HfO2 ferroelectric gate stack, the applied gate voltage is effectively amplified that causes increased electric field at the tunneling junction and reduced tunneling barrier width. Compared with the conventional p–n–p–n SOI TFET, the on–state current and switching state current ratio are appreciably increased; and the average subthreshold slope (SS is effectively reduced. The simulation results of Si:HfO2 ferroelectric p–n–p–n SOI TFET show significant improvement in transconductance (∼9.8X enhancement at high overdrive voltage and average subthreshold slope (∼35% enhancement over nine decades of drain current at room temperature, indicating that this device is a promising candidate to strengthen the performance of p–n–p–n and conventional TFET for a switching performance.

  20. L2₁ and XA Ordering Competition in Hafnium-Based Full-Heusler Alloys Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb).

    Science.gov (United States)

    Wang, Xiaotian; Cheng, Zhenxiang; Wang, Wenhong

    2017-10-20

    For theoretical designing of full-Heusler based spintroinc materials, people have long believed in the so-called Site Preference Rule (SPR). Very recently, according to the SPR, there are several studies on XA-type Hafnium-based Heusler alloys X₂YZ, i.e., Hf₂VAl, Hf₂CoZ (Z = Ga, In) and Hf₂CrZ (Z = Al, Ga, In). In this work, a series of Hf₂-based Heusler alloys, Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb), were selected as targets to study the site preferences of their atoms by first-principle calculations. It has been found that all of them are likely to exhibit the L2₁-type structure instead of the XA one. Furthermore, we reveal that the high values of spin-polarization of XA-type Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb) alloys have dropped dramatically when they form the L2₁-type structure. Also, we prove that the electronic, magnetic, and physics nature of these alloys are quite different, depending on the L2₁-type or XA-type structures.

  1. Genome-wide association study in 176,678 Europeans reveals genetic loci for tanning response to sun exposure

    NARCIS (Netherlands)

    Visconti, A. (Alessia); D.L. Duffy (David); F. Liu (Fan); G. Zhu (Gu); Wu, W. (Wenting); C. Yan (Chen); P.G. Hysi (Pirro); C. Zeng (Changqing); Sanna, M. (Marianna); M.M. Iles (Mark M.); P.P. Kanetsky (Peter P.); F. Demenais (Florence); M.A. Hamer (Merel); A.G. Uitterlinden (André); M.A. Ikram (Arfan); T.E.C. Nijsten (Tamar); N.G. Martin (Nicholas); M.H. Kayser (Manfred); T.D. Spector (Timothy); J. Han (Jiali); V. Bataille (Veronique); M. Falchi (Mario)

    2018-01-01

    textabstractThe skin's tendency to sunburn rather than tan is a major risk factor for skin cancer. Here we report a large genome-wide association study of ease of skin tanning in 176,678 subjects of European ancestry. We identify significant association with tanning ability at 20 loci. We confirm

  2. 46 CFR 176.620 - Description of the Alternative Hull Examination (AHE) Program for certain passenger vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Description of the Alternative Hull Examination (AHE... Hull and Tailshaft Examinations § 176.620 Description of the Alternative Hull Examination (AHE) Program for certain passenger vessels. The Alternative Hull Examination (AHE) Program provides you with an...

  3. 46 CFR 176.625 - Eligibility requirements for the Alternative Hull Examination (AHE) Program for certain passenger...

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Eligibility requirements for the Alternative Hull... CERTIFICATION Hull and Tailshaft Examinations § 176.625 Eligibility requirements for the Alternative Hull... if— (1) It is constructed of steel or aluminum; (2) It has an effective hull protection system; (3...

  4. 49 CFR 176.128 - Magazine stowage types “A”, “C” and Special Stowage.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Magazine stowage types âAâ, âCâ and Special... CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Stowage § 176.128 Magazine...” and “Special”. (b) Magazine stowage type “A”. Magazine stowage type A is required for those substances...

  5. 21 CFR 176.160 - Chromium (Cr III) complex of N-ethyl-N-heptadecylfluoro-octane sulfonyl glycine.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chromium (Cr III) complex of N-ethyl-N... § 176.160 Chromium (Cr III) complex of N-ethyl-N-heptadecylfluoro-octane sulfonyl glycine. The chromium... by weight of the chromium (Cr III) complex of heptadecylfluoro-octane sulfonic acid may be safely...

  6. Update of monotherapy trials with the new anti-androgen, Casodex (ICI 176,334). International Casodex Investigators

    DEFF Research Database (Denmark)

    Iversen, P

    1994-01-01

    Casodex (ICI 176,334) is a non-steroidal anti-androgen, which has a half-life compatible with once-daily oral dosing. In an open, phase II study on 267 patients given Casodex, 50 mg/day, an overall objective response (i.e. partial regression) was seen in 55.5% of patients (146 of 263) with a furt...

  7. 40 CFR 267.176 - What must I do when I want to stop using the containers?

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE FACILITIES OPERATING UNDER A STANDARDIZED PERMIT Use and Management of Containers § 267.176 What must I do when I want to stop using the containers? You must remove all hazardous waste and hazardous waste residues from...

  8. Readout of a 176 pixel FDM system for SAFARI TES arrays

    Science.gov (United States)

    Hijmering, R. A.; den Hartog, R.; Ridder, M.; van der Linden, A. J.; van der Kuur, J.; Gao, J. R.; Jackson, B.

    2016-07-01

    In this paper we present the results of our 176-pixel prototype of the FDM readout system for SAFARI, a TES-based focal-plane instrument for the far-IR SPICA mission. We have implemented the knowledge obtained from the detailed study on electrical crosstalk reported previously. The effect of carrier leakage is reduced by a factor two, mutual impedance is reduced to below 1 nH and mutual inductance is removed. The pixels are connected in stages, one quarter of the array half of the array and the full array, to resolve intermediate technical issues. A semi-automated procedure was incorporated to find all optimal settings for all pixels. And as a final step the complete array has been connected and 132 pixels have been read out simultaneously within the frequency range of 1-3.8MHz with an average frequency separation of 16kHz. The noise was found to be detector limited and was not affected by reading out all pixels in a FDM mode. With this result the concept of using FDM for multiplexed bolometer read out for the SAFARI instrument has been demonstrated.

  9. Glomerulogenesis: Can it predict the gestational age? A study of 176 fetuses

    Directory of Open Access Journals (Sweden)

    Panduranga Chikkannaiah

    2012-01-01

    Full Text Available Background: Accurate assessment of gestational age of fetuses is essential from both clinical and medico-legal point of view. Crown-rump length, crown-heel length, foot length, and the weight of the fetus are the commonly used parameters for fetal age assessment. However, this estimate often lacks accuracy and sometimes is necessary to combine other data. An analysis of the embryological development of nephrons in the kidney can assist in this determination. Objective : To correlate the gestational age with the histological study of sequential development of nephrons in fetal kidney. Materials and Methods: This study included 176 fetuses delivered between June 2009 and June 2011 and aged from 12 to 40 weeks. The number of glomerular generations counted in hematoxylin and eosin-stained microscopic sections of the kidneys were correlated with the reported period of gestation based on obstetrical methods. Regression analysis was used to determine the statistical significance of the correlation. Results: A high degree of statistically significant correlation was observed between the period of gestation and the number of glomerular generations (P value < 0.0001. Conclusion: The histological assessment of the number of glomerular generations in kidney can be used as a reliable method of estimating fetal age.

  10. SU-E-T-181: Clinical Implementation of Task Group 176

    Energy Technology Data Exchange (ETDEWEB)

    Burgdorf, B [University of Pennsylvania, Philadelphia, PA (United States); Yeager, C; Zhou, F; Hand, C [Albert Einstein Medical Center, Philadelphia, PA (United States)

    2015-06-15

    Purpose: The implementation of TG-176 with regards to immobilization devices and couch tops as they effect dosimetric treatment planning. Methods: The external devices used clinically were scanned to measure their HU values. Plans were created in the Eclipse treatment planning system (TPS) using these devices, one that accounted for the correct HU value of the each device and another that did not include the device as a structure. A dose subtraction was performed between the two plans to evaluate the dosimetric differences. The metrics used for evaluation included attenuation and surface dose. Plan parameters were varied to evaluate the impact of the devices in different clinical scenarios. Results: While the exact HU values of our results are clinic-dependent, the protocol being implemented is widely applicable. We recommend a four step process for implementing this task group. First, physics should scan each treatment device to determine accurate HU values. Second, CT therapists should include in the setup note which table top was used during patient CT simulation and are asked to make immobilization devices as uniform in thickness as possible. Therapists should also index the devices whenever possible so beam will traverse the same area of the device. Third, the dosimetrist should manually correct the HU value for any external device, including the couch. For H&N cases, the rails must be removed from the couch structure. When rails are used during treatments, it is important to make note of their exact position in the setup notes. Finally, physicians should be made aware that there could be changes in surface doses depending on whether or not immobilization devices or couch tops are in the beam path. Conclusion: The protocol outlined above was implemented to reduce the errors that arise from ignoring effects of external devices, thus ensuring safer, more accurate patient treatments.

  11. Impedance Characterization of the Capacitive field-Effect pH-Sensor Based on a thin-Layer Hafnium Oxide Formed by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Michael LEE

    2014-05-01

    Full Text Available As a sensing element, silicon dioxide (SiO2 has been applied within ion-sensitive field effect transistors (ISFET. However, a requirement of increasing pH-sensitivity and stability has observed an increased number of insulating materials that obtain high-k gate being applied as FETs. The increased high-k gate reduces the required metal oxide layer and, thus, the fabrication of thin hafnium oxide (HfO2 layers by atomic layer deposition (ALD has grown with interest in recent years. This metal oxide presents advantageous characteristics that can be beneficial for the advancements within miniaturization of complementary metal oxide semiconductor (CMOS technology. In this article, we describe a process for fabrication of HfO2 based on ALD by applying water (H2O as the oxygen precursor. As a first, electrochemical impedance spectroscopy (EIS measurements were performed with varying pH (2-10 to demonstrate the sensitivity of HfO2 as a potential pH sensing material. The Nyquist plot demonstrates a high clear shift of the polarization resistance (Rp between pH 6-10 (R2 = 0.9986, Y = 3,054X + 12,100. At acidic conditions (between pH 2-10, the Rp change was small due to the unmodified oxide gate (R2 = 0.9655, Y = 2,104X + 4,250. These preliminary results demonstrate the HfO2 substrate functioned within basic to neutral conditions and establishes a great potential for applying HfO2 as a dielectric material for future pH measuring FET sensors.

  12. Synergistic effect of carbon nanotube as sintering aid and toughening agent in spark plasma sintered molybdenum disilicide-hafnium carbide composite

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Biswajyoti; Asiq Rahman, O.S.; Sribalaji, M [Materials Science and Engineering, Indian Institute of Technology Patna, Bihta Kanpa Road, Bihta, Patna, Bihar 801103 (India); Bakshi, Srinivasa Rao [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Keshri, Anup Kumar, E-mail: anup@iitp.ac.in [Materials Science and Engineering, Indian Institute of Technology Patna, Bihta Kanpa Road, Bihta, Patna, Bihar 801103 (India)

    2016-12-15

    Hafnium carbide (HfC) along with sintering aids was consolidated at a relatively lower temperature i.e. 1600 °C (i.e. T=~0.41 T{sub m}) under a uniaxial load of 50 MPa by spark plasma sintering. Two different sintering aids such as molybdenum disilicide (MoSi{sub 2}) and carbon nanotube (CNT) were added to enhance the densification and lower the extent of grain growth in the sintered pellets. Density of the sintered pellet increased from 96.0±0.8% in HfC +5 wt% MoSi{sub 2} (HM) to 99.0±0.5% with the addition of 2 wt% CNT in HfC+5 wt% MoSi{sub 2} (HMC) at sintering temperature of 1600 °C. Further, the extent of grain growth drastically reduced from 204% in HM to 50% in HMC. Analysis of linear shrinkage during densification revealed that CNT addition increased densification rate and decreased the time required to reach the density of 99.0±0.5% at 1600 °C. Increased densification and lower degree of grain growth could be due to the synergistic effect offered by the CNT, which are as follows: (i) Lubrication effect of CNT, (ii) Lower activation energy for grain boundary diffusion (iii) Reduction in liquid phase sintering temperature and (iv) Grain boundary pinning. Fracture toughness of the sintered HM and HMC composite was obtained using indentation technique. By the addition of 2 wt% CNT in HM, drastic increase of 91% in fracture toughness was seen. This significant improvement in fracture toughness was due to the enhanced densification and relatively lower grain size of HMC. Also crack bridging, crack deflection, crack arrest, CNT and graphene sheet pull-out and swording played major role in toughening of HMC pellet.

  13. Technical Note: A simulation study on the feasibility of radiotherapy dose enhancement with calcium tungstate and hafnium oxide nano- and microparticles.

    Science.gov (United States)

    Sherck, Nicholas J; Won, You-Yeon

    2017-12-01

    To assess the radiotherapy dose enhancement (RDE) potential of calcium tungstate (CaWO 4 ) and hafnium oxide (HfO 2 ) nano- and microparticles (NPs). A Monte Carlo simulation study was conducted to gauge their respective RDE potentials relative to that of the broadly studied gold (Au) NP. The study was warranted due to the promising clinical and preclinical studies involving both CaWO 4 and HfO 2 NPs as RDE agents in the treatment of various types of cancers. The study provides a baseline RDE to which future experimental RDE trends can be compared to. All three materials were investigated in silico with the software Penetration and Energy Loss of Positrons and Electrons (PENELOPE 2014) developed by Francesc Salvat and distributed in the United States by the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory. The work utilizes the extensively studied Au NP as the "gold standard" for a baseline. The key metric used in the evaluation of the materials was the local dose enhancement factor (DEF loc ). An additional metric used, termed the relative enhancement ratio (RER), evaluates material performance at the same mass concentrations. The results of the study indicate that Au has the strongest RDE potential using the DEF loc metric. HfO 2 and CaWO 4 both underperformed relative to Au with lower DEF loc of 2-3 × and 4-100 ×, respectively. The computational investigation predicts the RDE performance ranking to be: Au > HfO 2 > CaWO 4 . © 2017 American Association of Physicists in Medicine.

  14. Open reading frame 176 in the photosynthesis gene cluster of Rhodobacter capsulatus encodes idi, a gene for isopentenyl diphosphate isomerase.

    OpenAIRE

    Hahn, F M; Baker, J A; Poulter, C D

    1996-01-01

    Isopentenyl diphosphate (IPP) isomerase catalyzes an essential activation step in the isoprenoid biosynthetic pathway. A database search based on probes from the highly conserved regions in three eukaryotic IPP isomerases revealed substantial similarity with ORF176 in the photosynthesis gene cluster in Rhodobacter capsulatus. The open reading frame was cloned into an Escherichia coli expression vector. The encoded 20-kDa protein, which was purified in two steps by ion exchange and hydrophobic...

  15. Study of the production of 177Lu through 176Yb (n, γ) 177Yb → 177Lu nuclear reaction

    International Nuclear Information System (INIS)

    Silva, Giovana Pasqualini da; Osso Junior, Joao Alberto

    2007-01-01

    The beta minus emitter 177 Lu is a promising therapeutic radioisotope for the curative treatment of cancer using labelled proteins. It has a half - life of T 1/2 = 6.71 day and maximum and average β - energies of 421 and 133 keV, resulting in a short range of radiation in tissue. The decay is accompanied by the emission of low energy γ-radiation with 208.3 keV (11%) and 113 keV (6.4%) suitable for simultaneous imaging, 177 Lu can be produced by two different routes, namely, by irradiation of natural Lu 2 O 3 target ( 176 Lu, 2.6%) or enriched (in 176 Lu) Lu 2 O 3 target, as also by irradiation of Yb target (Yb 2 O 3 ) followed by radiochemical separation of 177 Lu from Yb isotopes. The objective of this work is to study the production of 177 Lu through the indirect 176 Yb(n,γ) 177 Yb → 177 Lu nuclear reaction. The results of the production yield of 177 Lu will be shown and compared with the direct reaction. The method of choice for the chemical separation between Lu and Yb was the ion exchange, using an cation exchange resin in Cl - form and α-HIBA as eluent. Preliminary results showed a good separation of 177 Lu from Yb 2 O 3 indirect targets. (author)

  16. TU-D-9A-01: TG176: Dosimetric Effects of Couch Tops and Immobilization Devices

    International Nuclear Information System (INIS)

    Olch, A

    2014-01-01

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices are often overlooked. These devices also increase surface dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased surface dose compared to the ‘tennis racket’ style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations we make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of skin dose and attenuation, how to report these values, and for the vendors, an appeal is made to work together to provide accurate couch top models in planning systems. Learning Objectives

  17. Thermodynamic and kinetic studies in the systems alkali chloride-zinconium (or hafnium) tetrachloride: Part I. Vapour pressure measurements over hexachloro compounds and use of vapour pressure data in fractional decomposition

    International Nuclear Information System (INIS)

    Ray, H.S.; Bhat, B.G.; Reddy, G.S.; Biswas, A.K.

    1978-01-01

    A molten tin isoteniscope has been used to measure the vapour pressures over ZrCl 4 , HfCl 4 and the hexachlore zirconates (M 2 ZrCl 6 ) and the hexachloro hafnates (M 2 HfCl 6 ) of four alkali metals (M = Na,K,Rb,Cs). The method of preparation of these compounds and the effect of small amounts of residual alkali chlorides on the their vapour pressure are discussed. The pressure-temperature plots are examined in the light of some theoretical postulates. A scheme for separation of hafnium from zirconoium by multistage fractional decomposition of the hexachlore compounds of any alkali metal is described. The scheme, which is analogous to rectification in liquid-vapour systems, employs a countercurrent flow of Zr(Hf)Cl 4 in a gas stream and a moving bed of alkali chlorides. The separation is based on the difference in the dissociation equilibrium for zirconium and hafnium compounds. Stage calculations for such a scheme and the main conclusions of a computational work are presented. (author)

  18. Laparoscopic cholecystectomy in patients over 70 years of age: review of 176 cases Colecistectomía laparoscópica en pacientes mayores de 70 años: nuestra experiencia en 176 casos

    Directory of Open Access Journals (Sweden)

    F. J. Pérez Lara

    2006-01-01

    Full Text Available Introduction: we assessed the results of laparoscopic cholecystectomy in 176 patients over the age of 70 years. Patients and methods: the study included all patients older than 70 years of age who underwent laparoscopic surgery cholelithiasis during the previous ten years. Variables studied included age, sex, type of operation (programmed/emergency, comorbidity, anesthetic risk, intraoperative cholangiography, conversion to open surgery, number of trocars, reoperation, residual choledocholithiasis, postoperative hospital stay, morbidity and mortality. Results: the study included 176 patients (23.29% men and 76.71% women. The mean age was 74.86 years. The mean hospital stay was 1.27 days, with 16.98% morbidity and 0.56% mortality. Conclusions: laparoscopic cholecystectomy is a safe procedure in older patients. It results in faster recovery, a shorter postoperative stay and lower rates of morbidity and mortality than open bile duct surgery.Objetivo: el objetivo de nuestro estudio es el de evaluar los resultados obtenidos en 176 pacientes mayores de 70 años intervenidos mediante colecistectomía laparoscópica. Pacientes y métodos: se incluyen en el estudio todos los pacientes mayores de 70 años diagnosticados de colelitiasis intervenidos por laparoscopia en los diez últimos años. Analizamos los siguientes parámetros: edad, sexo, tipo de intervención (programada/urgente, comorbilidad, riesgo anestésico, colangiografía intraoperatoria, conversión a cirugía abierta, número de trócares, reintervención, coledocolitiasis residual, estancia hospitalaria postoperatoria y morbimortalidad. Resultados: incluimos en el estudio un total de 176 pacientes, de los cuales el 23,29% son varones y 76,71%, tienen una edad media de 74.86 años. En los resultados globales la estancia media hospitalaria es de 1,27 días, morbilidad 16,98% y mortalidad de 0,57%. Conclusiones: la colecistectomía laparoscópica es un procedimiento seguro en pacientes mayores

  19. Synthesis and luminescence behavior of SrGd1.76Eu0.24O4 host for display and dosimetric applications

    Science.gov (United States)

    Singh, Jyoti; Manam, J.; Singh, Fouran

    2018-05-01

    Novel SrGd1.76Eu0.24O4 materials were synthesized by conventional high-temperature solid-state reaction method in air ambiance. The structural and luminescence properties of as-prepared phosphors were explored by XRD, FESEM, TEM, PL and TL techniques. The confirmation of orthorhombic phase formation was obtained by XRD studies. The agglomerated ginger-like morphology of as-synthesized SrGd1.76Eu0.24O4 samples was unfolded by FESEM and TEM studies. Upon 276 and 395 nm UV excitation, SrGd1.76Eu0.24O4 phosphors showed intense red emission. The TL glow curve of SrGd1.76Eu0.24O4 irradiated with γ-rays exhibits two well-resolved peaks at 393 K and 598 K having a shoulder at 537 K. Linearity in a wide dose range 500 Gy-3 kGy are observed in the as-formed SrGd1.76Eu0.24O4 samples. Intense red emission, linear dose response and high reproducibility of SrGd1.76Eu0.24O4 samples broadly indicated its suitability for display and TL dosimetry applications.

  20. An upper limit on hypertriton production in collisions of Ar(1.76 A GeV) + KCl

    Energy Technology Data Exchange (ETDEWEB)

    Agakishiev, G.; Chernenko, S.; Fateev, O.; Zanevsky, Y. [Joint Institute of Nuclear Research, Dubna (Russian Federation); Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J.A. [Univ. de Santiago de Compostela, LabCAF. F. Fisica, Santiago de Compostela (Spain); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A. [LIP-Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Coimbra (Portugal); Boehmer, M.; Friese, J.; Gernhaeuser, R.; Jurkovic, M.; Kruecken, R.; Maier, L.; Weber, M. [Technische Universitaet Muenchen, Physik Department E12, Garching (Germany); Boyard, J.L.; Hennino, T.; Liu, T.; Moriniere, E.; Ramstein, B. [Universite Paris Sud, Institut de Physique Nucleaire (UMR 8608), CNRS/IN2P3, Orsay Cedex (France); Destefanis, M.; Gilardi, C.; Kuehn, W.; Lange, J.S.; Metag, V.; Spruck, B. [Justus Liebig Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Dohrmann, F.; Kaempfer, B.; Kotte, R.; Naumann, L.; Wendisch, C.; Wuestenfeld, J. [Helmholtz-Zentrum Dresden-Rossendorf, Institut fuer Strahlenphysik, Dresden (Germany); Dybczak, A.; Michalska, B.; Palka, M.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M. [Jagiellonian University of Cracow, Smoluchowski Institute of Physics, Krakow (Poland); Epple, E.; Fabbietti, L.; Lapidus, K.; Siebenson, J. [Excellence Cluster ' ' Origin and Structure of the Universe' ' , Garching (Germany); Finocchiaro, P.; Schmah, A.; Spataro, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Catania (Italy); Froehlich, I.; Lorenz, M.; Markert, J.; Michel, J.; Muentz, C.; Pachmayer, Y.C.; Pechenova, O.; Rehnisch, L.; Rustamov, A.; Scheib, T.; Schuldes, H.; Stroebele, H.; Tarantola, A.; Teilab, K. [Goethe-Universitaet, Institut fuer Kernphysik, Frankfurt (Germany); Galatyuk, T.; Gonzalez-Diaz, D. [Technische Universitaet Darmstadt, Darmstadt (Germany); Golubeva, M.; Guber, F.; Ivashkin, A.; Karavicheva, T.; Kurepin, A.; Reshetin, A.; Sadovsky, A. [Russian Academy of Science, Institute for Nuclear Research, Moscow (Russian Federation); Gumberidze, M. [Technische Universitaet Darmstadt, Darmstadt (Germany); Universite Paris Sud, Institut de Physique Nucleaire (UMR 8608), CNRS/IN2P3, Orsay Cedex (France); Heinz, T.; Holzmann, R.; Koenig, I.; Koenig, W.; Kolb, B.W.; Lang, S.; Pechenov, V.; Pietraszko, J.; Schwab, E.; Sturm, C.; Traxler, M.; Yurevich, S. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Iori, I. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Milano (Italy); Krasa, A.; Krizek, F.; Kugler, A.; Sobolev, Yu.G.; Tlusty, P.; Wagner, V. [Academy of Sciences of Czech Republic, Nuclear Physics Institute, Rez (Czech Republic); Kuc, H. [Jagiellonian University of Cracow, Smoluchowski Institute of Physics, Krakow (Poland); Universite Paris Sud, Institut de Physique Nucleaire (UMR 8608), CNRS/IN2P3, Orsay Cedex (France); Mousa, J.; Tsertos, H. [University of Cyprus, Department of Physics, Nicosia (Cyprus); Stroth, J. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Goethe-Universitaet, Institut fuer Kernphysik, Frankfurt (Germany); Collaboration: HADES Collaboration

    2013-11-15

    A high-statistic data sample of Ar(1.76 AGeV)+KCl events recorded with HADES is used to search for a hypertriton signal. An upper production limit per centrality-triggered event of 1.04 x 10{sup -3} on the 3 {sigma} level is derived. Comparing this value with the number of successfully reconstructed {Lambda} hyperons allows to determine an upper limit on the ratio N{sub 3{sub {Lambda}H}}/N{sub {Lambda}}, which is confronted with statistical and coalescence-type model calculations. (orig.)

  1. An upper limit on hypertriton production in collisions of Ar(1.76 A GeV) + KCl

    International Nuclear Information System (INIS)

    Agakishiev, G.; Chernenko, S.; Fateev, O.; Zanevsky, Y.; Belver, D.; Cabanelas, P.; Castro, E.; Garzon, J.A.; Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.; Boehmer, M.; Friese, J.; Gernhaeuser, R.; Jurkovic, M.; Kruecken, R.; Maier, L.; Weber, M.; Boyard, J.L.; Hennino, T.; Liu, T.; Moriniere, E.; Ramstein, B.; Destefanis, M.; Gilardi, C.; Kuehn, W.; Lange, J.S.; Metag, V.; Spruck, B.; Dohrmann, F.; Kaempfer, B.; Kotte, R.; Naumann, L.; Wendisch, C.; Wuestenfeld, J.; Dybczak, A.; Michalska, B.; Palka, M.; Przygoda, W.; Salabura, P.; Trebacz, R.; Wisniowski, M.; Epple, E.; Fabbietti, L.; Lapidus, K.; Siebenson, J.; Finocchiaro, P.; Schmah, A.; Spataro, S.; Froehlich, I.; Lorenz, M.; Markert, J.; Michel, J.; Muentz, C.; Pachmayer, Y.C.; Pechenova, O.; Rehnisch, L.; Rustamov, A.; Scheib, T.; Schuldes, H.; Stroebele, H.; Tarantola, A.; Teilab, K.; Galatyuk, T.; Gonzalez-Diaz, D.; Golubeva, M.; Guber, F.; Ivashkin, A.; Karavicheva, T.; Kurepin, A.; Reshetin, A.; Sadovsky, A.; Gumberidze, M.; Heinz, T.; Holzmann, R.; Koenig, I.; Koenig, W.; Kolb, B.W.; Lang, S.; Pechenov, V.; Pietraszko, J.; Schwab, E.; Sturm, C.; Traxler, M.; Yurevich, S.; Iori, I.; Krasa, A.; Krizek, F.; Kugler, A.; Sobolev, Yu.G.; Tlusty, P.; Wagner, V.; Kuc, H.; Mousa, J.; Tsertos, H.; Stroth, J.

    2013-01-01

    A high-statistic data sample of Ar(1.76 AGeV)+KCl events recorded with HADES is used to search for a hypertriton signal. An upper production limit per centrality-triggered event of 1.04 x 10 -3 on the 3 σ level is derived. Comparing this value with the number of successfully reconstructed Λ hyperons allows to determine an upper limit on the ratio N 3 Λ H /N Λ , which is confronted with statistical and coalescence-type model calculations. (orig.)

  2. PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

    International Nuclear Information System (INIS)

    Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

    2016-01-01

    Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176 Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176 Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

  3. PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

    Science.gov (United States)

    Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

    2016-11-01

    Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

  4. 6-Peroxo-6-zirconium crown and its hafnium analogue embedded in a triangular polyanion: [M6(O2)6(OH)6(gamma-SiW10O36)3]18- (M = Zr, Hf).

    Science.gov (United States)

    Bassil, Bassem S; Mal, Sib Sankar; Dickman, Michael H; Kortz, Ulrich; Oelrich, Holger; Walder, Lorenz

    2008-05-28

    We have synthesized and structurally characterized the unprecedented peroxo-zirconium(IV) containing [Zr6(O2)6(OH)6(gamma-SiW10O36)3]18- (1). Polyanion 1 comprises a cyclic 6-peroxo-6-zirconium core stabilized by three decatungstosilicate units. We have also prepared the isostructural hafnium(IV) analogue [Hf6(O2)6(OH)6(gamma-SiW10O36)3]18- (2). We investigated the acid/base and redox properties of 1 by UV-vis spectroscopy and electrochemistry studies. Polyanion 1 represents the first structurally characterized Zr-peroxo POM with side-on, bridging peroxo units. The simple, one-pot synthesis of 1 and 2 involving dropwise addition of aqueous hydrogen peroxide could represent a general procedure for incorporating peroxo groups into a large variety of transition metal and lanthanide containing POMs.

  5. Hafnium and neodymium isotopes and REY distribution in the truly dissolved, nanoparticulate/colloidal and suspended loads of rivers in the Amazon Basin, Brazil

    Science.gov (United States)

    Merschel, Gila; Bau, Michael; Schmidt, Katja; Münker, Carsten; Dantas, Elton L.

    2017-09-01

    Radiogenic isotopes in river sediments and river waters have been widely used in provenance studies, as these samples naturally integrate the geology/chemistry of the entire catchment. While the Hf and Nd isotope systems are coupled during igneous processes, they are decoupled during supergene processes at the Earth's surface, which is reflected by the isotope composition of riverine sediments. We present the first data for both Hf and Nd isotope compositions of the dissolved (0.2 μm-filtrates rich in nanoparticles and colloids, NPCs) and the truly dissolved (1 kDa-ultrafiltrates) load of rivers. Hafnium and Nd isotope compositions and concentrations of the Rare Earths and Yttrium (REY) and Hf were determined for suspended particles (>0.2 μm) as well as for the dissolved and the truly dissolved load of the Rio Solimões, the Amazon's largest tributary draining the Andes, and of the Rio Negro, an organic NPC- and particle-rich river draining the rainforest of northern Amazonia. We also analyzed the Nd isotope compositions of suspended sediments and 0.2 μm-filtered water samples from the Amazon River and its tributaries Rio Tapajos, Rio Xingu and Rio Jari. Our novel results clearly show that the decoupling of the Hf and Nd isotope systems is related to incongruent weathering processes on the continent, as this decoupling can already be observed in the different Hf and Nd pools, i.e. in the particulate, the NPC-dominated dissolved and the truly dissolved load of rivers. In the Rio Negro and Rio Solimões, a strong particle size-dependent difference in Hf isotope composition is observed. Values of εHf become more radiogenic as filter poresize decreases, which can be related to the density- and size-dependent distribution of Hf-rich minerals, e.g. zircons, and their absence from the truly dissolved pool. In contrast, the Nd isotope composition of Amazonian river waters reflects that of their catchment geology. Tributaries draining the Precambrian Brazilian and

  6. Zirconium Zr and hafnium Hf

    International Nuclear Information System (INIS)

    Busev, A.I.; Tiptsova, V.G.; Ivanov, V.M.

    1978-01-01

    The basic methods for extracting and determining Zr(4) and Hf(4) are described. Diantipyrinemethane and its alkyl homologs selectively extract Zr and Hf from HNO 3 solutions in the presence of nitrates. Zr is selectively extracted with tetraethyldiamide of heptyl phosphoric acid (in benzene) as well as with 2-thenoyltrifluoroacetone (in an acid). The latter reagents is suitable for rapid determination of 95 Zr in a mixture with 95 Nb and other fragments. The complexometric determination of Zr is based on formation of a stable complex of Zr with EDTA. The titration is carried out in the presence of n-sulfobenzene-azo-pyrocatechol, eriochrome black T. The determination is hindered by Hf, fluoride-, phosphate-, oxalate- and tartrate-ions. The method is used for determining Zr in zircon and eudialyte ore. Zr is determined photometrically with the aid of xylenol orange, arsenazo 3 and pyrocatechol violet (in phosphorites). Hf is determined in the presence of Zr photometrically with the aid of xylenol orange or methyl-thymol blue. The method is based on Zr being masked with hydrogen peroxide in the presence of sulfate-ions

  7. Cathodoluminescence of Irradiated Hafnium Dioxide

    Science.gov (United States)

    2011-03-01

    Martin and Michael Rhoby for their hard work in fixing assorted problems that cropped up during the course of my thesis work. Emily A. Purcell...Cathodoluminescence Microscopy of Inorganic Solids. New York: Plenum Press, 1990. [13] D. Drouin, A. R. Couture, D. Joly , X. Tastet, V. Aimez and R. Gauvin

  8. Alkali metal hafnium oxide scintillators

    Science.gov (United States)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

    2018-05-08

    The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  9. Transducer Like Proteins of Campylobacter jejuni 81-176: Role in chemotaxis and colonization of the chicken gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Gireesh eRajashekara

    2015-05-01

    Full Text Available Transducer Like Proteins (Tlps, also known as Methyl accepting chemotaxis proteins (MCP, enable enteric pathogens to respond to changing nutrient levels in the environment by mediating taxis towards or away from specific chemoeffector molecules such as nutrients. Despite recent advances in the characterization of chemotaxis responses in Campylobacter jejuni, the impact of Tlps on the adaptation of this pathogen to disparate niches and hosts is not fully characterized. The latter is particularly evident in the case of C. jejuni 81-176, a strain that is known to be highly invasive. Furthermore, the cytoplasmic group C Tlps (Tlp5, 6, and 8 was not extensively evaluated. Here, we investigated the role of C. jejuni 81-176 Tlps in chemotaxis towards various substrates, biofilm formation, in vitro interaction with human intestinal cells, and chicken colonization. We found that the ∆tlp6 and ∆tlp10 mutants exhibited decreased chemotaxis towards aspartate whereas the ∆tlp6 mutant displayed a decreased chemotaxis towards Tri-Carboxylic Acid (TCA cycle intermediates such as pyruvate, isocitrate, and succinate. Our findings also corroborated that more than one Tlp is involved in mediating chemotaxis towards the same nutrient. The deletion of tlps affected important phenotypes such as motility, biofilm formation, and invasion of human intestinal epithelial cells (INT-407. The ∆tlp8 mutant displayed increased motility in soft agar and showed decreased biofilm formation. The ∆tlp8 and ∆tlp9 mutants were significantly defective in invasion in INT-407 cells. The ∆tlp10 mutant was defective in colonization of the chicken proximal and distal gastrointestinal tract, while the ∆tlp6 and ∆tlp8 mutants showed reduced colonization of the duodenum and jejunum. Our results highlight the importance of Tlps in C. jejuni’s adaptation and pathobiology.

  10. Reconciliation of the excess 176Hf conundrum in meteorites: Recent disturbances of the Lu-Hf and Sm-Nd isotope systematics

    Science.gov (United States)

    Bast, Rebecca; Scherer, Erik E.; Sprung, Peter; Mezger, Klaus; Fischer-Gödde, Mario; Taetz, Stephan; Böhnke, Mischa; Schmid-Beurmann, Hinrich; Münker, Carsten; Kleine, Thorsten; Srinivasan, Gopalan

    2017-09-01

    The long-lived 176Lu-176Hf and 147Sm-143Nd radioisotope systems are commonly used chronometers, but when applied to meteorites, they can reveal disturbances. Specifically, Lu-Hf isochrons commonly yield dates up to ∼300 Myr older than the solar system and varying initial 176Hf/177Hf values. We investigated this problem by attempting to construct mineral and whole rock isochrons for eucrites and angrites. Meteorites from different parent bodies exhibit similar disturbance features suggesting that a common process is responsible. Minerals scatter away from isochron regressions for both meteorite classes, with low-Hf phases such as plagioclase and olivine typically being most displaced above (or left of) reference isochrons. Relatively Hf-rich pyroxene is less disturbed but still to the point of steepening Lu-Hf errorchrons. Using our Lu-Hf and Sm-Nd data, we tested various Hf and Lu redistribution scenarios and found that decoupling of Lu/Hf from 176Hf/177Hf must postdate the accumulation of significant radiogenic 176Hf. Therefore early irradiation or diffusion cannot explain the excess 176Hf. Instead, disturbed meteorite isochrons are more likely caused by terrestrial weathering, contamination, or common laboratory procedures. The partial dissolution of phosphate minerals may predominantly remove rare earth elements including Lu, leaving relatively immobile and radiogenic Hf behind. Robust Lu-Hf (and improved Sm-Nd) meteorite geochronology will require the development of chemical or physical methods for removing unsupported radiogenic Hf and silicate-hosted terrestrial contaminants without disturbing parent-daughter ratios.

  11. Analysis of electron pair production in the collision system Ar+KCl at 1.76 AGeV; Analyse der Elektronpaarproduktion im Stosssystem Ar+KCl bei 1,76 AGeV

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Simon Martin

    2008-06-30

    The HADES-spectrometer at GSI is used to measure the production of the light vector mesons {rho}, {omega} and {phi} at SIS energies. Therefore, the medium sized collision system Ar+KCl was measured at 1.76 AGeV kinetic energy of beam particles. In this system the density of particle tracks is much larger as compared to the formerly used collision system C+C, making it necessary to upgrade the data analysis. The previous method of hard-cuts - used for particle identification - was replaced by a newly developed multi-variate analysis based on an artificial neural network. This algorithm has the benefit, that it is more robust against fluctuations in one or more of the used detector observables. This increases the overall efficiency and purity of the analysis procedure. Furthermore, the reconstruction of particle tracks inside the HADES spectrometer is based on a few position information, only. During analysis of raw data, these information are combined to a artificially large manifold of tracks. This leads to the general problem that one has to select the maximum number of true physical tracks out of this set of tracks per event. A new method of track selection is used to filter the data not only to select single tracks, but also to identify electron pairs created during Dalitz-decay of {pi}{sup 0} mesons, which build the bulk of combinatorial background. The result of the analysis is an efficiency corrected invariant mass spectrum of electron pairs, normalized to the mean number of pions per event. The spectrum consists of more than 16,000 pairs with an invariant mass larger than 150 MeV. In total more than 150000 pairs were found. A first comparison with the spectra calculated by using the old analysis approach shows a 30% enhancement in yield of reconstructed electron pairs. A first comparison with a simple thermal model implemented by the Pluto event generator, opens the possibility to compare the measured pair yield of {omega} and {phi} mesons via m{sub T

  12. Analysis of electron pair production in the collision system Ar+KCl at 1.76 AGeV

    International Nuclear Information System (INIS)

    Lang, Simon Martin

    2008-01-01

    The HADES-spectrometer at GSI is used to measure the production of the light vector mesons ρ, ω and φ at SIS energies. Therefore, the medium sized collision system Ar+KCl was measured at 1.76 AGeV kinetic energy of beam particles. In this system the density of particle tracks is much larger as compared to the formerly used collision system C+C, making it necessary to upgrade the data analysis. The previous method of hard-cuts - used for particle identification - was replaced by a newly developed multi-variate analysis based on an artificial neural network. This algorithm has the benefit, that it is more robust against fluctuations in one or more of the used detector observables. This increases the overall efficiency and purity of the analysis procedure. Furthermore, the reconstruction of particle tracks inside the HADES spectrometer is based on a few position information, only. During analysis of raw data, these information are combined to a artificially large manifold of tracks. This leads to the general problem that one has to select the maximum number of true physical tracks out of this set of tracks per event. A new method of track selection is used to filter the data not only to select single tracks, but also to identify electron pairs created during Dalitz-decay of π 0 mesons, which build the bulk of combinatorial background. The result of the analysis is an efficiency corrected invariant mass spectrum of electron pairs, normalized to the mean number of pions per event. The spectrum consists of more than 16,000 pairs with an invariant mass larger than 150 MeV. In total more than 150000 pairs were found. A first comparison with the spectra calculated by using the old analysis approach shows a 30% enhancement in yield of reconstructed electron pairs. A first comparison with a simple thermal model implemented by the Pluto event generator, opens the possibility to compare the measured pair yield of ω and φ mesons via m T -scaling with the yield of η mesons

  13. Corn Stover and Wheat Straw Combustion in a 176-kW Boiler Adapted for Round Bales

    Directory of Open Access Journals (Sweden)

    Joey Villeneuve

    2013-11-01

    Full Text Available Combustion trials were conducted with corn stover (CS and wheat straw (WS round bales in a 176-kW boiler (model Farm 2000. Hot water (80 °C stored in a 30,000-L water tank was transferred to a turkey barn through a plate exchanger. Gross calorific value measured in the laboratory was 17.0 and 18.9 MJ/kg DM (dry matter for CS and WS, respectively. Twelve bales of CS (1974 kg DM total, moisture content of 13.6% were burned over a 52-h period and produced 9.2% ash. Average emissions of CO, NOx and SO2 were 2725, 9.8 and 2.1 mg/m3, respectively. Thermal efficiency was 40.8%. For WS, six bales (940 kg DM total, MC of 15% were burned over a 28-h period and produced 2.6% ash. Average emissions of CO, NOx and SO2 were 2210, 40.4 and 3.7 mg/m3, respectively. Thermal efficiency was 68.0%. A validation combustion trial performed a year later with 90 CS bales confirmed good heating performance and the potential to lower ash content (6.2% average.

  14. Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of N'-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide.

    Science.gov (United States)

    Emam, Sanaa M; El-Saied, Fathy A; Abou El-Enein, Saeyda A; El-Shater, Heba A

    2009-03-01

    Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of furan-2-carbaldehyde 4-methoxy-N-anilinoacetohydrazone were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment and molar conductivity. Mononuclear complexes are obtained with 1:1 molar ratio except complexes 3 and 9 which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a neutral bidentate one and coordination occurs via the carbonyl oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the enolic oxygen atom, azomethine nitrogen atom and the oxygen atom of furan ring. Moreover, the ligand behaves as a neutral tridentate and coordination occurs via the carbonyl oxygen, azomethine nitrogen and furan oxygen atoms as well as a monobasic bidentate and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complex 10 possesses a square planar geometry. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes.

  15. Determination of hafnium at the 10−4% level (relative to zirconium content) using neutron activation analysis, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Smolik, Marek; Polkowska-Motrenko, Halina; Hubicki, Zbigniew; Jakóbik-Kolon, Agata; Danko, Bożena

    2014-01-01

    Graphical abstract: -- Highlights: •We worked out ICP-MS method of Hf determination in Zr and Zr compounds. •We used NAA method as reference one. •We obtained pure zirconium matrix by ion exchange (Diphonix ® resin). •These permit to determine ≥1 × 10 −4 % Hf in Zr sample by ICP MS with good precision and accuracy. -- Abstract: Hafnium at the very low level of 1–8 ppm (in relation to zirconium) was determined in zirconium sulfate solutions (originating from investigations of the separation of ca. 44 ppm Hf from zirconium by means of the ion exchange method) by using three independent methods: inductively coupled plasma mass spectrometry (ICP MS), neutron activation analysis (NAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of NAA and ICP MS determinations were consistent with each other across the entire investigated range (the RSD of both methods did not exceed 38%). The results of ICP-AES determination were more diverse, particularly at less than 5 ppm Hf (RSD was significantly higher: 29–253%). The ion exchange method exploiting Diphonix ® resin proved sufficient efficiency in Zr–Hf separation when the initial concentration ratio of the elements ([Zr] 0 /[Hf] 0 ) ranged from 1200 to ca. 143,000

  16. Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions.

    Science.gov (United States)

    Turonova, Hana; Briandet, Romain; Rodrigues, Ramila; Hernould, Mathieu; Hayek, Nabil; Stintzi, Alain; Pazlarova, Jarmila; Tresse, Odile

    2015-01-01

    During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy (CLSM) was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions (MAC). The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells) coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

  17. Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions

    Directory of Open Access Journals (Sweden)

    Hana eTuronova

    2015-07-01

    Full Text Available During the last years, Campylobacter has emerged as the leading cause of bacterial foodborne infections in developed countries. Described as an obligate microaerophile, Campylobacter has puzzled scientists by surviving a wide range of environmental oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative damage from macrophages to cause human infection. In this study, confocal laser scanning microscopy was used to explore the biofilm development of two well-described Campylobacter jejuni strains (NCTC 11168 and 81-176 prior to or during cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure for 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions. The presence of motile cells within the biofilm confirmed the maturation of the C. jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significant enhancement of biofilm formation during the early stages of the process. Exposure to these conditions during biofilm cultivation induced an even greater biofilm development for both strains, indicating that oxygen demand for biofilm formation is higher than for planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not linked to oxygen stimulation. These unexpected data advocate challenging studies by reconsidering the paradigm of fastidious requirements for C. jejuni growth when various subpopulations (from quiescent to motile cells coexist in biofilms. These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

  18. A spanish mineral of zirconium and hafnium. Separation of the two elements by liquid-liquid extraction, using tributyl phosphate as chelating agent; Beneficio de un mineral espanol de circonio-hafnio. Separacion de ambos elementos por extraccion liquido-liquido, empleando fosfato de tributilo como agente de quelacion

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Sanchez, F; Cruz Castillo, F. de la; Fernandez Cellini, R

    1962-07-01

    The zirconium and Hafnium oxides are obtained from a Spanish mineral of zircon with an average contest of 55% in ZrO{sub 2}-HfO{sub 2}. An alkaline fusion to open the mineral, followed by a purification by crystallization as (Zr O-Hf O)Cl{sub 2} H{sub 2}O or as (Zr-Hf) (SO{sub 4}){sub 2}. 4H{sub 2}O, is used. A discussion of the best experimental conditions for opening the mineral and of the purification method is made. (Author) 45 refs.

  19. Spectroscopy of virtual photons in Ar+KCl collisions at E{sub kin}=1.76 AGeV; Spektroskopie virtueller Photonen in Ar+KCl Stoessen bei E{sub kin}=1,76 AGeV

    Energy Technology Data Exchange (ETDEWEB)

    Jurkovic, Martin

    2010-01-14

    The objective of this thesis is the analysis of virtual photon emission originating from the decays of the short lived hadrons produced in Ar+KCl collisions at E{sub kin}=1.76 AGeV. The measured observables were the reconstructed e{sup +}e{sup -} pairs and their kinematic distributions. The data were recorded with the HADES spectrometer assembled at GSI Helmholtzzentrum fuer Schwerionenforschung GmbH in Darmstadt, Germany. Due to the considerably higher combinatorial background originating from the {gamma}-conversion as compared to that from light collision systems (p+p,C+C) investigated so far with HADES, a new method for identification and suppression of conversion electrons using the signal pattern in the RICH-detector was studied. An improvement of signal to background ratio (S/B) reaching 30% was achieved. For the procedure of calculating the e{sup +}/e{sup -} track efficiencies a detailed study of RICH detector signals was performed, leading to an overall improved description of ring observables in the simulation. In total, 32545pm 385 e{sup +}e{sup -} signal pairs with an opening angle {alpha}{sub ee} > 15 and 0.1 < p{sub e} < 1.1 GeV/c were identified, with 7402{+-}222 pairs in the so-called {eta} mass region (0.15 < M{sub ee} < 0.55 GeV/c{sup 2}) and 253{+-}25 for masses M{sub ee} > 0.55 GeV/c{sup 2}. A clear signal from direct {omega} decay with S/B {proportional_to}1 was identified for the first time in the SIS18 energy regime. The extraction of the {omega} yield per produced {pi}{sup 0} results in N({omega})/N({pi}{sup 0}) {approx} (4,5 {+-} 2,5(stat) {+-} 2(sys)) .10{sup -8}. The e{sup +}e{sup -} production in the {eta} mass region was compared to the expected {eta} Dalitz decay {eta}{yields}{gamma}e{sup +}e{sup -} contribution. The measured e{sup +}e{sup -} yield is higher by a factor F = 3.4{+-}0.2(stat){+-}0.6(sys){+-}0.9({eta}) as compared to the {eta} production. The excitation function of the extra e{sup +}/e{sup -} sources shows similar energy

  20. Spectroscopy of virtual photons in Ar+KCl collisions at Ekin=1.76 AGeV

    International Nuclear Information System (INIS)

    Jurkovic, Martin

    2010-01-01

    The objective of this thesis is the analysis of virtual photon emission originating from the decays of the short lived hadrons produced in Ar+KCl collisions at E kin =1.76 AGeV. The measured observables were the reconstructed e + e - pairs and their kinematic distributions. The data were recorded with the HADES spectrometer assembled at GSI Helmholtzzentrum fuer Schwerionenforschung GmbH in Darmstadt, Germany. Due to the considerably higher combinatorial background originating from the γ-conversion as compared to that from light collision systems (p+p,C+C) investigated so far with HADES, a new method for identification and suppression of conversion electrons using the signal pattern in the RICH-detector was studied. An improvement of signal to background ratio (S/B) reaching 30% was achieved. For the procedure of calculating the e + /e - track efficiencies a detailed study of RICH detector signals was performed, leading to an overall improved description of ring observables in the simulation. In total, 32545pm 385 e + e - signal pairs with an opening angle α ee > 15 and 0.1 e ee 2 ) and 253±25 for masses M ee > 0.55 GeV/c 2 . A clear signal from direct ω decay with S/B ∝1 was identified for the first time in the SIS18 energy regime. The extraction of the ω yield per produced π 0 results in N(ω)/N(π 0 ) ∼ (4,5 ± 2,5(stat) ± 2(sys)) .10 -8 . The e + e - production in the η mass region was compared to the expected η Dalitz decay η→γe + e - contribution. The measured e + e - yield is higher by a factor F = 3.4±0.2(stat)±0.6(sys)±0.9(η) as compared to the η production. The excitation function of the extra e + /e - sources shows similar energy dependence as the π 0 production. Possible candidates for these extra e + e - sources are the Δ Dalitz decays, the NN and πN bremsstrahlung and partly the direct decay of the ρ meson. Relative to the π 0 production in both Ar+KCl and C+C collisions, the e + e - production of unknown composition in Ar

  1. Study of the production of {sup 177}Lu through {sup 176}Yb (n, {gamma}) {sup 177}Yb {yields} {sup 177}Lu nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Giovana Pasqualini da; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: gpsilva@ipen.br; jaosso@ipen.br

    2007-07-01

    The beta minus emitter {sup 177}Lu is a promising therapeutic radioisotope for the curative treatment of cancer using labelled proteins. It has a half - life of T{sub 1/2} = 6.71 day and maximum and average {beta}{sup -} energies of 421 and 133 keV, resulting in a short range of radiation in tissue. The decay is accompanied by the emission of low energy {gamma}-radiation with 208.3 keV (11%) and 113 keV (6.4%) suitable for simultaneous imaging, {sup 177}Lu can be produced by two different routes, namely, by irradiation of natural Lu{sub 2}O{sub 3} target ({sup 176}Lu, 2.6%) or enriched (in {sup 176}Lu) Lu{sub 2}O{sub 3} target, as also by irradiation of Yb target (Yb{sub 2}O{sub 3}) followed by radiochemical separation of {sup 177}Lu from Yb isotopes. The objective of this work is to study the production of {sup 177}Lu through the indirect {sup 176}Yb(n,{gamma}){sup 177}Yb {yields} {sup 177}Lu nuclear reaction. The results of the production yield of {sup 177}Lu will be shown and compared with the direct reaction. The method of choice for the chemical separation between Lu and Yb was the ion exchange, using an cation exchange resin in Cl{sup -} form and {alpha}-HIBA as eluent. Preliminary results showed a good separation of {sup 177}Lu from Yb{sub 2}O{sub 3} indirect targets. (author)

  2. Virtual Compton scattering and the generalized polarizabilities of the proton at Q²=0.92 and 1.76 GeV²

    OpenAIRE

    Fonvieille, H; Laveissiere, G; Degrande, N; Jaminion, S; Jutier, C; Todor, L; Di Salvo, R; Van Hoorebeke, Luc; Alexa, LC; Anderson, BD; Aniol, KA; Arundell, K; Audit, G; Auerbach, L; Baker, FT

    2012-01-01

    Virtual Compton scattering (VCS) on the proton has been studied at the Jefferson Laboratory using the exclusive photon electroproduction reaction ep -> ep gamma. This paper gives a detailed account of the analysis which has led to the determination of the structure functions P-LL - P-TT/epsilon and P-LT and the electric and magnetic generalized polarizabilities (GPs) alpha(E) (Q(2)) and beta(M) (Q(2)) at values of the four-momentum transfer squared Q(2) = 0.92 and 1.76 GeV2. These data, toget...

  3. BATING A REFERENCE INSTALLATION BASED ON CONTROLLED-POTENTIAL COULOMETRY METOD IN THE FRAME OF IMPROVING THE STATE PRIMARY STANDARD GET 176 AND ITS MEASUREMENT CAPABILITIES

    Directory of Open Access Journals (Sweden)

    V. M. Zyskin

    2016-01-01

    Full Text Available The results of developing of reference installation, based on a controlled-potential coulometry, in the frame of improving the State primary standard of the units of mass (molar fraction and mass (molar concentration of a component in the liquid and solid substances and materials GET 176 are presented. The physical principles of controlled-potential coulometry, content and metrological characteristics of the developed installation are considered. Measurement results of copper, iron and lead contents in the certified reference materials of metals' solutions and CRM of brass produced by BAM, Germany, obtained using reference installation are given.

  4. Efficient UV-emitting X-ray phosphors: octahedral Zr(PO4)6 luminescence centers in potassium hafnium-zirconium phosphates K2Hf1-xZrx(PO4)2 and KHf2(1-x)Zr2x(PO4)3

    International Nuclear Information System (INIS)

    Torardi, C.C.; Miao, C.R.; Li, J.

    2003-01-01

    Potassium hafnium-zirconium phosphates, K 2 Hf 1-x Zr x (PO 4 ) 2 and KHf 2(1-x) Zr 2x (PO 4 ) 3 , are broad-band UV-emitting phosphors. At room temperature, they have emission peak maxima at approximately 322 and 305 nm, respectively, under 30 kV peak molybdenum X-ray excitation. Both phosphors demonstrate luminescence efficiencies that make them up to ∼60% as bright as commercially available CaWO 4 Hi-Plus. The solid-state and flux synthesis conditions, and X-ray excited UV luminescence of these two phosphors are discussed. Even though the two compounds have different atomic structures, they contain zirconium in the same active luminescence environment as that found in highly efficient UV-emitting BaHf 1-x Zr x (PO 4 ) 2 . All the three materials have hafnium and zirconium in octahedral coordination via oxygen-atom corner sharing with six separate PO 4 tetrahedra. This octahedral Zr(PO 4 ) 6 moiety appears to be an important structural element for efficient X-ray excited luminescence, as are the edge-sharing octahedral TaO 6 chains for tantalate emission

  5. Particle-number conserving analysis for the 2-quasiparticle and high-K multi-quasiparticle states in doubly-odd 174,176Lu

    International Nuclear Information System (INIS)

    Li Bingheng; Lei Yi'an; Zhang Zhenhua

    2013-01-01

    Two-quasiparticle bands and low-lying excited high-K four-, six-, and eight-quasiparticle bands in the doubly-odd 174,176 Lu are analyzed by using the cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are taken into account exactly. The proton and neutron Nilsson level schemes for 174,176 Lu are taken from the adjacent odd-A Lu and Hf isotopes, which are adopted to reproduce the experimental bandhead energies of the one-quasiproton and one-quasineutron bands of these odd-A Lu and Hf nuclei, respectively. Once the quasiparticle configurations are determined, the experimental bandhead energies and the moments of inertia of these two- and multi-quasiparticle bands are well reproduced by PNC-CSM calculations. The Coriolis mixing of the low-K (K=|Ω 1 -Ω 2 |) two-quasiparticle band of the Gallagher-Moszkowski doublet with one nucleon in the Ω=1/2 orbital is analyzed. (authors)

  6. PET/CT alignment calibration with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of PET detector

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qingyang [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Ma, Tianyu; Wang, Shi; Liu, Yaqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Gu, Yu, E-mail: guyu@ustb.edu.cn [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Dai, Tiantian, E-mail: maxinedtt@163.com [Department of Radiation Oncology, China-Japan Friendship Hospital, Beijing 100029 (China)

    2016-11-01

    Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic {sup 176}Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic {sup 176}Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

  7. Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2.

    Science.gov (United States)

    Laveissière, G; Todor, L; Degrande, N; Jaminion, S; Jutier, C; Di Salvo, R; Van Hoorebeke, L; Alexa, L C; Anderson, B D; Aniol, K A; Arundell, K; Audit, G; Auerbach, L; Baker, F T; Baylac, M; Berthot, J; Bertin, P Y; Bertozzi, W; Bimbot, L; Boeglin, W U; Brash, E J; Breton, V; Breuer, H; Burtin, E; Calarco, J R; Cardman, L S; Cavata, C; Chang, C-C; Chen, J-P; Chudakov, E; Cisbani, E; Dale, D S; de Jager, C W; De Leo, R; Deur, A; d'Hose, N; Dodge, G E; Domingo, J J; Elouadrhiri, L; Epstein, M B; Ewell, L A; Finn, J M; Fissum, K G; Fonvieille, H; Fournier, G; Frois, B; Frullani, S; Furget, C; Gao, H; Gao, J; Garibaldi, F; Gasparian, A; Gilad, S; Gilman, R; Glamazdin, A; Glashausser, C; Gomez, J; Gorbenko, V; Grenier, P; Guichon, P A M; Hansen, J O; Holmes, R; Holtrop, M; Howell, C; Huber, G M; Hyde-Wright, C E; Incerti, S; Iodice, M; Jardillier, J; Jones, M K; Kahl, W; Kato, S; Katramatou, A T; Kelly, J J; Kerhoas, S; Ketikyan, A; Khayat, M; Kino, K; Kox, S; Kramer, L H; Kumar, K S; Kumbartzki, G; Kuss, M; Leone, A; LeRose, J J; Liang, M; Lindgren, R A; Liyanage, N; Lolos, G J; Lourie, R W; Madey, R; Maeda, K; Malov, S; Manley, D M; Marchand, C; Marchand, D; Margaziotis, D J; Markowitz, P; Marroncle, J; Martino, J; McCormick, K; McIntyre, J; Mehrabyan, S; Merchez, F; Meziani, Z E; Michaels, R; Miller, G W; Mougey, J Y; Nanda, S K; Neyret, D; Offermann, E A J M; Papandreou, Z; Pasquini, B; Perdrisat, C F; Perrino, R; Petratos, G G; Platchkov, S; Pomatsalyuk, R; Prout, D L; Punjabi, V A; Pussieux, T; Quémenér, G; Ransome, R D; Ravel, O; Real, J S; Renard, F; Roblin, Y; Rowntree, D; Rutledge, G; Rutt, P M; Saha, A; Saito, T; Sarty, A J; Serdarevic, A; Smith, T; Smirnov, G; Soldi, K; Sorokin, P; Souder, P A; Suleiman, R; Templon, J A; Terasawa, T; Tieulent, R; Tomasi-Gustaffson, E; Tsubota, H; Ueno, H; Ulmer, P E; Urciuoli, G M; Vanderhaeghen, M; Van De Vyver, R; Van der Meer, R L J; Vernin, P; Vlahovic, B; Voskanyan, H; Voutier, E; Watson, J W; Weinstein, L B; Wijesooriya, K; Wilson, R; Wojtsekhowski, B B; Zainea, D G; Zhang, W-M; Zhao, J; Zhou, Z-L

    2004-09-17

    We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.

  8. Hospital-based Clostridium difficile infection surveillance reveals high proportions of PCR ribotypes 027 and 176 in different areas of Poland, 2011 to 2013.

    Science.gov (United States)

    Pituch, Hanna; Obuch-Woszczatyński, Piotr; Lachowicz, Dominika; Wultańska, Dorota; Karpiński, Paweł; Młynarczyk, Grażyna; van Dorp, Sofie M; Kuijper, Ed J

    2015-01-01

    As part of the European Clostridium difficile infections (CDI) surveillance Network (ECDIS-Net), which aims to build capacity for CDI surveillance in Europe, we constructed a new network of hospital-based laboratories in Poland. We performed a survey in 13 randomly selected hospital-laboratories in different sites of the country to determine their annual CDI incidence rates from 2011 to 2013. Information on C. difficile laboratory diagnostic testing and indications for testing was also collected. Moreover, for 2012 and 2013 respectively, participating hospital-laboratories sent all consecutive isolates from CDI patients between February and March to the Anaerobe Laboratory in Warsaw for further molecular characterisation, including the detection of toxin-encoding genes and polymerase chain reaction (PCR)-ribotyping. Within the network, the mean annual hospital CDI incidence rates were 6.1, 8.6 and 9.6 CDI per 10,000 patient-days in 2011, 2012, and 2013 respectively. Six of the 13 laboratories tested specimens only on the request of a physician, five tested samples of antibiotic-associated diarrhoea or samples from patients who developed diarrhoea more than two days after admission (nosocomial diarrhoea), while two tested all submitted diarrhoeal faecal samples. Most laboratories (9/13) used tests to detect glutamate dehydrogenase and toxin A/B either separately or in combination. In the two periods of molecular surveillance, a total of 166 strains were characterised. Of these, 159 were toxigenic and the majority belonged to two PCR-ribotypes: 027 (n=99; 62%) and the closely related ribotype 176 (n=22; 14%). The annual frequency of PCR-ribotype 027 was not significantly different during the surveillance periods (62.9% in 2012; 61.8% in 2013). Our results indicate that CDIs caused by PCR-ribotype 027 predominate in Polish hospitals participating in the surveillance, with the closely related 176 ribotype being the second most common agent of infection.

  9. Crystal identification for a dual-layer-offset LYSO based PET system via Lu-176 background radiation and mean shift algorithm

    Science.gov (United States)

    Wei, Qingyang; Ma, Tianyu; Xu, Tianpeng; Zeng, Ming; Gu, Yu; Dai, Tiantian; Liu, Yaqiang

    2018-01-01

    Modern positron emission tomography (PET) detectors are made from pixelated scintillation crystal arrays and readout by Anger logic. The interaction position of the gamma-ray should be assigned to a crystal using a crystal position map or look-up table. Crystal identification is a critical procedure for pixelated PET systems. In this paper, we propose a novel crystal identification method for a dual-layer-offset LYSO based animal PET system via Lu-176 background radiation and mean shift algorithm. Single photon event data of the Lu-176 background radiation are acquired in list-mode for 3 h to generate a single photon flood map (SPFM). Coincidence events are obtained from the same data using time information to generate a coincidence flood map (CFM). The CFM is used to identify the peaks of the inner layer using the mean shift algorithm. The response of the inner layer is deducted from the SPFM by subtracting CFM. Then, the peaks of the outer layer are also identified using the mean shift algorithm. The automatically identified peaks are manually inspected by a graphical user interface program. Finally, a crystal position map is generated using a distance criterion based on these peaks. The proposed method is verified on the animal PET system with 48 detector blocks on a laptop with an Intel i7-5500U processor. The total runtime for whole system peak identification is 67.9 s. Results show that the automatic crystal identification has 99.98% and 99.09% accuracy for the peaks of the inner and outer layers of the whole system respectively. In conclusion, the proposed method is suitable for the dual-layer-offset lutetium based PET system to perform crystal identification instead of external radiation sources.

  10. Passive behaviour of zirconium, hafnium and niobium

    International Nuclear Information System (INIS)

    Hornkjoel, S.

    1990-01-01

    The paper deals mainly with the results of stationary and transient polarization measurements together with capacitance measurements on passive electrodes of Zr, Hf and Nb over the entire pH-scale. The passive current densities are exstremely low, and essentially both pH and potential independent, exept for Nb at high pH. The extrapolated potential of zero inverse capacitance seems to be different from the extrapolated potential of zero film thickness for Zr and Hf, but not for Nb. The potential versus time curves at constant current show a downwards bending for Zr and Hf. It is shown that the pitting potentials of Zr and Hf are dependent of the concentration of halide ions and the type of halide ion, but not on pH. It is also shown that the pitting induction is second-order stimulated by chloride ions and first-order hindered by sulphate ions. Results from electron transfer reactions on passive niobium are reported. 9 refs

  11. Nanomechanical properties of hafnium nitride coating

    International Nuclear Information System (INIS)

    Chen Yao; Laha, Tapas; Balani, Kantesh; Agarwal, Arvind

    2008-01-01

    Nanomechanical properties of plasma-sprayed HfN coating with and without hot isostatic pressing (HIP) treatment were evaluated using nanoindentation. For HIPed HfN coating, the elastic modulus (E) and yield strength increase whereas the hardness (H), H/E ratio and fraction of the elastic work decrease. HIPed HfN coating shows a larger pile-up around the indent as compared to as-sprayed HfN. HIPing causes densification and improvement in inter-splat bonding which subsequently lead to increase in nanomechanical properties

  12. High-pressure torsion of hafnium

    International Nuclear Information System (INIS)

    Edalati, Kaveh; Horita, Zenji; Mine, Yoji

    2010-01-01

    Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30 GPa to form an ultrafine-grained structure with a gain size of ∼180 nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30 GPa. A hydride formation is detected after straining at the pressure of 4 GPa. The hydride phase decomposes either by application of a higher pressure as 30 GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360 Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75 GPa, respectively) are achieved following the high-pressure torsion.

  13. Development of a certified reference material for composition of high-purity copper as a transfer standard within GET 176-2013

    Directory of Open Access Journals (Sweden)

    Veniamin M. Zyskin

    2017-01-01

    Full Text Available Introduction. The paper gives information on the development of a certified reference material (CRM for composition of high-purity copper (Cu CRM UNIIM. The CRM is included as the transfer standard into the State primary standard of the mass (molar fraction and mass (molar concentration of the component in liquid and solid substances and materials based on coulometry GET 176-2013.Materials and methods. The CRM represents pieces of oxygen-free copper wire rod, brand KMB, produced according to GOST R 53803-2010, weighing from 0.5 to 1g. The CRM is packed in plastic vials with the capacity of 30 or 50 cm3. The certified characteristic of the CRM is copper mass fraction in copper wire rod, expressed in percentages. The certified value for copper mass fraction was established by the primary method of controlled-potential coulometry using the State primary standard GET 176-2013.Results. The permitted interval of the certified value for copper mass fraction in the CRM is from 99,950 % to 100,000 %. The relative expanded uncertainty (k=2 of the certified value for copper mass fraction does not exceed 0,030 %; the relative standard uncertainty due to inhomogeneity does not exceed 0.010 %; the relative standard uncertainty due to instability does not exceed 0.010 %. The shelf life of the developed CRM is 10 years provided that standard storage conditions are ensured.Discussion and conclusions. The developed CRM is included into the State register of type approved RMs under the number GSO 10800-2016. The CRM of high-purity copper (Cu CRM UNIIM as a transfer standard is intended for reproduction, storage and transfer of the copper mass fraction unit to other reference materials and chemical reagents by the method of comparison using a comparator and by conducting direct measurements. This CRM may also be used:– for verification of measuring instruments (MIs according to the state verification schedule described in GOST R 8.735.0-2014,– for calibration

  14. Coupled Nd-142, Nd-143 and Hf-176 Isotopic Data from 3.6-3.9 Ga Rocks: New Constraints on the Timing of Early Terrestrial Chemical Reservoirs

    Science.gov (United States)

    Bennett, Vickie C.; Brandon, alan D.; Hiess, Joe; Nutman, Allen P.

    2007-01-01

    Increasingly precise data from a range of isotopic decay schemes, including now extinct parent isotopes, from samples of the Earth, Mars, Moon and meteorites are rapidly revising our views of early planetary differentiation. Recognising Nd-142 isotopic variations in terrestrial rocks (which can only arise from events occurring during the lifetime of now extinct Sm-146 [t(sub 1/2)=103 myr]) has been an on-going quest starting with Harper and Jacobsen. The significance of Nd-142 variations is that they unequivocally reflect early silicate differentiation processes operating in the first 500 myr of Earth history, the key time period between accretion and the beginning of the rock record. The recent establishment of the existence of Nd-142 variations in ancient Earth materials has opened a new range of questions including, how widespread is the evidence of early differentiation, how do Nd-142 compositions vary with time, rock type and geographic setting, and, combined with other types of isotopic and geochemical data, what can Nd-142 isotopic variations reveal about the timing and mechanisms of early terrestrial differentiation? To explore these questions we are determining high precision Nd-142, Nd-143 and Hf-176 isotopic compositions from the oldest well preserved (3.63- 3.87 Ga), rock suites from the extensive early Archean terranes of southwest Greenland and western Australia.

  15. Electric quadrupole moments and strong interaction effects in pionic atoms of 165Ho, 175Lu, 176Lu, 179Hf and 181Ta

    International Nuclear Information System (INIS)

    Olaniyi, B.; Shor, A.; Cheng, S.C.; Dugan, G.; Wu, C.S.

    1981-05-01

    The effective quadrupole moments Q sub(eff) of the nuclei of 165 Ho, 175 Lu, 176 Lu, 179 Hf and 181 Ta were accurately measured by detecting the pionic atom 5g-4f x-rays of the elements. The spectroscopic quadrupole moments, Q sub(spec), were obtained by correcting Q sub(eff) for nuclear finite size effect, distortion of the pion wave function by the pion-nucleus strong interaction, and contribution to the energy level splittings by the strong interaction. The intrinsic quadrupole moments, Q 0 , were obtained by projecting Q sub(spec) into the frame of reference fixed on the nucleus. The shift, epsilon 0 , and broadening, GAMMA 0 , of the 4f energy level due to the strong interactions between the pion and the nucleons for all the elements were also measured. Theoretical values of epsilon 0 and GAMMA 0 were calculated and compared to the experimental values. The measured values of Q 0 were compared with the existing results in muonic and pionic atoms. The measured values of epsilon 0 and GAMMA 0 were also compared with existing values. (auth)

  16. Coulomb-nuclear interference measurements of 168Yb, 176Hf, 178Hf, and 180Hf and lifetime measurements in 186Hg

    International Nuclear Information System (INIS)

    Nettles, W.G.

    1979-01-01

    Alpha scattering measurements were performed at center-of-mass energies near the Coulomb barrier. These energies allow for nuclear as well as pure Coulomb forces to play a significant role in the excitation process. The interference of these two forces is very sensitive to the sign of the E4 ground-state moment, whereas pure Coulomb excitation is not. Systematics of the E4 moments of the rare earth mass region indicate a transition in the magnitude and sign of the reduced matrix element of the M(E4) operator between 0 + and 4 + states from small and positive to large and negative between Yb and W. Previous Coulomb-nuclear interference measurements show that this reduced matrix element for 180 Hf is large and negative. The present results agree with that conclusion. It is also shown that the above reduced matrix element for 178 Hf, like that of 180 Hf, is large and negative. The small and positive moment (matrix element) for 168 Yb is seen to be consistent with the experimental data. No conclusions are drawn for the E4 moment in 176 Hf. The measurement of nuclear lifetimes shorter than 500 ps requires the use of plastic scintilltor detectors. These detectors, however have very poor energy resolution. A system is described that uses plastic scintillators with a magnetic lens spectrometer for energy selection. The system was used to measure the lifetime of the 522-keV 0 + sate in 186 Hf. A data analysis method using higher-order distribution moments is also presented

  17. Analysis of proteomes released from in vitro cultured eight Clostridium difficile PCR ribotypes revealed specific expression in PCR ribotypes 027 and 176 confirming their genetic relatedness and clinical importance at the proteomic level

    Czech Academy of Sciences Publication Activity Database

    Dresler, J.; Krůtová, M.; Fučíková, A.; Klimentová, J.; Hrůzová, V.; Ďuráčová, M.; Houdková, K.; Salovská, B.; Matějková, J.; Hubálek, Martin; Pajer, P.; Píša, L.; Nyč, O.

    2017-01-01

    Roč. 9, Aug 14 (2017), č. článku 45. ISSN 1757-4749 Institutional support: RVO:61388963 Keywords : Clostridium difficile * label-free quantification * proteome * PCR ribotype 027 * PCR ribotype 176 Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.756, year: 2016 https://gutpathogens.biomedcentral.com/articles/10.1186/s13099-017-0194-9

  18. Separation of zirconium and hafnium; Separation du zirconium et de l'hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Saint-James, D [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    This account is more chemical than metallurgical in character. The reason for this is that so-called 'nuclear metal' must fulfil standards of purity which only chemical processes can attain. This paper must therefore be considered as a preliminary study, from which the metallurgists can form an idea of the treatments leading to the production of the metal. (author) [French] Cet expose a un caractere chimique plutot que metallurgique. La raison en est que le metal dit 'nucleaire' a des exigences de purete que seuls des processus chimiques peuvent satisfaire. Il faut donc considerer cet expose comme un preliminaire, permettant de donner une idee aux metallurgistes des traitements qui aboutissent a l'elaboration du metal. (auteur)

  19. Results of Time-of-Flight Neutron Capture Measurements of 176,177,178,179 Hf-enriched and nat Hf samples at 10 m, 30 m and 60 m stations of GELINA

    International Nuclear Information System (INIS)

    Ware, T.C.; Dean, C.J.; Borella, A.; Kopecky, S.; Moens, A.; Schillebeeckx, P.; Janeva, N.; Moxon, M.C.

    2014-04-01

    Neutron capture measurements have been performed at the time-offlight facility GELINA to determine neutron resonance parameters for 174,176,177,178,179,180 Hf. In total, 16 distinct experiments were conducted at the 12 m, 28 m and 58 m capture stations using C 6 D 6 detectors with a moderated neutron beam and the accelerator operating at 50 Hz or 800 Hz. Measurements were performed with nat Hf metallic samples and oxide samples enriched in 176 Hf, 177 Hf, 178 Hf and 179 Hf. This report describes the experimental details required to deliver the experimental capture yields to the EXFOR data library which is maintained by the Nuclear Energy Agency of the OECD and the Nuclear Data Section of the IAEA. The experimental conditions and data reduction procedures are described. In addition, the full covariance information based on the AGS concept is given, such that resonance parameters together with their covariances can be derived in a least squares adjustment to the data. (author)

  20. Toward metrological traceability for DNA fragment ratios in GM quantification. 1. Effect of DNA extraction methods on the quantitative determination of Bt176 corn by real-time PCR.

    Science.gov (United States)

    Corbisier, Philippe; Broothaerts, Wim; Gioria, Sabrina; Schimmel, Heinz; Burns, Malcolm; Baoutina, Anna; Emslie, Kerry R; Furui, Satoshi; Kurosawa, Yasunori; Holden, Marcia J; Kim, Hyong-Ha; Lee, Yun-Mi; Kawaharasaki, Mamoru; Sin, Della; Wang, Jing

    2007-05-02

    An international CCQM-P60 pilot study involving eight national metrological institutes was organized to investigate if the quantification of genetically modified (GM) corn powder by real-time PCR was affected by the DNA extraction method applied. Four commonly used extraction methods were compared for the extraction of DNA from a GM Bt176 corn powder. The CTAB-based method yielded the highest DNA template quantity and quality. A difference in the 260 nm/230 nm absorbance ratio was observed among the different extraction methods. Real-time amplification of sequences specific for endogenous genes zein and hmg as well as transgenic sequences within the cryIA(b) gene and a fragment covering the junction between the transformed DNA and the plant genome were used to determine the GM percentage. The detection of the transgenic gene was affected by the quantity and quality of template used for the PCR reaction. The Bt176 percentages measured on diluted or purified templates were statistically different depending on the extraction method applied.

  1. Why do pathological stage IA lung adenocarcinomas vary from prognosis?: a clinicopathologic study of 176 patients with pathological stage IA lung adenocarcinoma based on the IASLC/ATS/ERS classification.

    Science.gov (United States)

    Zhang, Jie; Wu, Jie; Tan, Qiang; Zhu, Lei; Gao, Wen

    2013-09-01

    Patients with pathological stage IA adenocarcinoma (AC) have a variable prognosis, even if treated in the same way. The postoperative treatment of pathological stage IA patients is also controversial. We identified 176 patients with pathological stage IA AC who had undergone a lobectomy and mediastinal lymph node dissection at the Shanghai Chest Hospital, Shanghai, China, between 2000 and 2006. No patient had preoperative treatment. The histologic subtypes of all patients were classified according to the 2011 International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary lung AC classification. Patients' 5-year overall survival (OS) and 5-year disease-free survival (DFS) were calculated using Kaplan-Meier and Cox regression analyses. One hundred seventy-six patients with pathological stage IA AC had an 86.6% 5-year OS and 74.6% 5-year DFS. The 10 patients with micropapillary predominant subtype had the lowest 5-year DFS (40.0%).The 12 patients with solid predominant with mucin production subtype had the lowest 5-year OS (66.7%). Univariate and multivariate analysis showed that sex and prognositic groups of the IASLC/ATS/ERS histologic classification were significantly associated with 5-year DFS of pathological stage IA AC. Our study revealed that sex was an independent prognostic factor of pathological stage IA AC. The IASLC/ATS/ERS classification of lung AC identifies histologic categories with prognostic differences that could be helpful in clinical therapy.

  2. Energy independent partial wave analysis of the reactions π+-p→Nππ between 1.36 and 1.76GeV c.m.s. energy

    International Nuclear Information System (INIS)

    Dolbeau, J.; Triantis, F.A.; Neveu, M.; Cadiet, F.

    1975-01-01

    A new partial wave analysis of the three reactions π - p→pπ - π 0 , π - p→nπ + π - , and π + p→pπ + π 0 is presented at nine c.m. energies between 1.36 and 1.76GeV, using about 91300 Nππ events. Within the framework of the generalized isobar model it is possible to describe the data with Δ, rho and sigma(ππ, i=0) production, as well as to reproduce the π - p→nπ 0 π 0 and π + p→nπ + π + cross sections. New prescriptions for the description of sigma and for the centrifugal barrier term are obtained. Furthermore, at the highest energy, there is evidence for N* production and for the presence of a ππ interaction, contributing about 5% to the cross sections of the reaction π - p→pπ - π 0 and π + p→pπ + π 0 . Finally, Argand plots are presented, showing the main inelastic couplings for ten resonances in this energy range [fr

  3. Comparison between exercise electrocardiogram and thallium 201 myocardial perfusion imaging during exercise, after dipyridamole and at rest, for the diagnosis of stable angina pectoris. 176 cases were studied with coronary angiography

    International Nuclear Information System (INIS)

    Machecourt, J.; Denis, B.; Comet, M.; Wolf, J.E.; Dimitriou, R.; Pellet, J.; Noel, P.M.

    1981-01-01

    The purpose of this study was to compare the diagnostic interest of the electrocardiogram stress test (EST) and the thallium myocardial imaging during exercise (TIE). For this, the cases of 176 patients with stable angina pectoris who underwent a coronary arteriogram were studied. These patients were divided into two groups: a first group of 113 patients without a previous history of myocardial infarction, nor a Q wave on their electrocardiogram and a second group of 63 patients with angina pectoris after a previous myocardial infarction. All patients underwent a combined EST and TIE. The sensitivity and the specificity of the EST and the TIE were studied, and the post-test risk after either a positive test or a negative test was calculated according to Bayes' theorem. In the first group 62 patients had a coronary stenosis and 51 had a normal arteriogram. The sensitivity of the TIE was higher than that of the EST: 80% versus 64%, p < 0.01. Even when the maximum effort was not reached during the EST, the TIE kept the same sensitivity. The diagnosis of angina pectoris cannot be absolutely established by the separate use of the TIE or the EST. However, their predictive value increases when both are correlated. Moreover, for female patients, the TIE is more specific than the EST because of the higher frequency of false positive or equivocal results of the EST in that population. (Auth.)

  4. 40 CFR 82.176 - Applicability.

    Science.gov (United States)

    2010-07-01

    ... replacement of class I or II compounds causes formulators to change other components in a product, formulators... environmental and human health risk associated with the use of any class I or class II substitute. (7... consumed, transformed or destroyed in the manufacturing or use process are exempt from reporting...

  5. 46 CFR 176.645 - AHE Procedure.

    Science.gov (United States)

    2010-10-01

    ... hull for examination, except internal tanks that carry fuel (unless damage or deterioration is discovered or suspect), sewage, or potable water. Internal sewage and potable water tanks may be examined... repairs if the assessment or repairs cannot be completed to the satisfaction of the OCMI while the vessel...

  6. 32 CFR 176.5 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... services that has no established limitation on the amount of time of residence to help meet long-term needs of homeless individuals and families; and, (v) Any other activity that clearly meets an identified.... Homeless person. (1) An individual or family who lacks a fixed, regular, and adequate nighttime residence...

  7. 32 CFR 176.10 - Applicability.

    Science.gov (United States)

    2010-07-01

    ... received by HHS prior to October 25, 1994, and were spending with the Secretary of HHS on that date. These... application, but property has not been assigned or otherwise disposed of by the Military Department, the LRA...

  8. Publications | Page 176 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... and institutions to build local capacity through funding, knowledge sharing, and ... Through books, articles, research publications, and studies, we aim to widen ... A group of agricultural practitioners from all over Sudan gathered in the city of ...

  9. Search Results | Page 176 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... (FBOs) are one of the driving forces for political and social change. ... In this project, IDRC will partner with the Norman Paterson School of International Affairs (NPSIA) in furthering a program of research on international human rights. Project.

  10. 49 CFR 176.83 - Segregation.

    Science.gov (United States)

    2010-10-01

    ... presence of one or more steel bulkheads or decks between them or a combination thereof. Intervening spaces... substance but vary only in their water content (for example, sodium sulfide in Division 4.2 or Class 8) or... applied. (11) Certain exceptions from segregation for waste cyanides or waste cyanide mixtures or...

  11. Reference: 176 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available tricted to a few tissues, including senescing leaves. Disruption of GPT2 has no obvious effect on growth and development under greenh...ouse conditions, whereas the mutations gpt1-1 and gpt1-2

  12. 32 CFR 176.30 - LRA application.

    Science.gov (United States)

    2010-07-01

    ... Plan(s) or any other existing housing, social service, community, economic, or other development plans...) Notices of interest proposing assistance to homeless persons and/or families. (i) A description of the... activities need not be limited to expressions of interest in property, but may also include discussions of...

  13. 21 CFR 176.300 - Slimicides.

    Science.gov (United States)

    2010-04-01

    ... disodium ethylenebis(dithiocarba-mate) Disodium cyanodithioimidocarbonate n-Dodecylguanidine hydrochloride... pound, calculated as silver fluoride, per ton of paper produced. Silver nitrate Sodium dimethyldithiocarbamate Sodium 2-mercaptobenzothiazole Sodium pentachlorophenate Sodium trichlorophenate 1,3,6,8...

  14. 49 CFR 176.137 - Portable magazine.

    Science.gov (United States)

    2010-10-01

    ... requirements: (1) It must be weather-tight, constructed of wood or metal lined with wood at least 2 cm (0.787... wood, a portable magazine must be framed of nominal 5 cm × 10 cm (2×4 inch) lumber, and sheathed with... used for the stowage of Class 1 (explosive) materials under such construction, handling, and stowage...

  15. Search Results | Page 176 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Filter by type .... Ugandan-Canadian partnership advances research on disability studies ... Without formal research and concrete data, a knowledge gap exists that hinders disabled peoples' organizations in Uganda from effectively advocating ...

  16. 46 CFR 160.176-8 - Materials.

    Science.gov (United States)

    2010-10-01

    ... transmission rate of inflation chamber materials must not be increased by more than 10% after being subjected... other metal part in contact with it; and (ii) Unless it is expendable (such as an inflation medium... type. (c) Inflation chamber materials—(1) All materials. (i) The average permeability of inflation...

  17. 49 CFR 176.2 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... not penetrate accommodations, machinery spaces or other work areas by means of entrances or other... cargo, to prevent damage during transportation. Explosives anchorage means an anchorage so designated... whose stowage together may result in undue hazards in the case of leakage, spillage, or other accident...

  18. Control of the hafnium content in Co samples by SSMS

    International Nuclear Information System (INIS)

    Lukaszew, R.A.; Cretella, R.F.

    1989-01-01

    The production of 60 Co requires a strict control of the chemical composition of the cobalt before irradiation in order to avoid the activation of some undesirable elements and to constrain the presence of slow neutron poisons. A methodology by SSMS for the survey analysis of metallic Co prior to its irradiation in the nuclear reactor at Embalse (Cdba., Argentina) is described. The low detection limit attained for Hf (below 0.5 ppm) is outlined. The results obtained for some other impurities without a standard reference are compared with atomic emission spectrographic data and show satisfactory agreement. (orig.)

  19. Production of long-lived hafnium isomers in reactor irradiations

    Czech Academy of Sciences Publication Activity Database

    Adam, Jindřich

    -, - (2006), s. 48-56 ISSN 1574-1818 R&D Projects: GA MŠk 1P04LA213 Institutional research plan: CEZ:AV0Z10480505 Keywords : production * Hf Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  20. Electric field cycling behavior of ferroelectric hafnium oxide.

    Science.gov (United States)

    Schenk, Tony; Schroeder, Uwe; Pešić, Milan; Popovici, Mihaela; Pershin, Yuriy V; Mikolajick, Thomas

    2014-11-26

    HfO2 based ferroelectrics are lead-free, simple binary oxides with nonperovskite structure and low permittivity. They just recently started attracting attention of theoretical groups in the fields of ferroelectric memories and electrostatic supercapacitors. A modified approach of harmonic analysis is introduced for temperature-dependent studies of the field cycling behavior and the underlying defect mechanisms. Activation energies for wake-up and fatigue are extracted. Notably, all values are about 100 meV, which is 1 order of magnitude lower than for conventional ferroelectrics like lead zirconate titanate (PZT). This difference is mainly atttributed to the one to two orders of magnitude higher electric fields used for cycling and to the different surface to volume ratios between the 10 nm thin films in this study and the bulk samples of former measurements or simulations. Moreover, a new, analog-like split-up effect of switching peaks by field cycling is discovered and is explained by a network model based on memcapacitive behavior as a result of defect redistribution.

  1. Elastic and Thermodynamic Properties of Zirconium and Hafnium ...

    Indian Academy of Sciences (India)

    65

    Here Rh3V is chosen as the parent binary compound and the doping ..... Grüneisen parameter ζ [44] are two key quantities in solid state problems due to their .... The authors wish to thank DRDO (ER & IPR), New Delhi for the financial support.

  2. Electronic structure of hafnium: A Compton profile study

    Indian Academy of Sciences (India)

    To extract the true Compton profile from the raw data, the raw data were cor- rected for ... For the present sample and experimental conditions, the contribution of .... are in better agreement with the simple renormalized free atom calculations for.

  3. Hafnium(IV) complexation with oxalate at variable temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Friend, Mitchell T.; Wall, Nathalie A. [Washington State Univ., Pullmanm, WA (United States). Dept. of Chemistry

    2017-08-01

    Appropriate management of fission products in the reprocessing of spent nuclear fuel (SNF) is crucial in developing advanced reprocessing schemes. The addition of aqueous phase complexing agents can prevent the co-extraction of these fission products. A solvent extraction technique was used to study the complexation of Hf(IV) - an analog to fission product Zr(IV) - with oxalate at 15, 25, and 35 C in 1 M HClO{sub 4} utilizing a {sup 175+181}Hf radiotracer. The mechanism of the solvent extraction system of 10{sup -5} M Hf(IV) in 1 M HClO{sub 4} to thenoyltrifluoroacetone (TTA) in toluene demonstrated a 4{sup th}-power dependence in both TTA and H{sup +}, with Hf(TTA){sub 4} the only extractable species. The equilibrium constant for the extraction of Hf(TTA){sub 4} was determined to be log K{sub ex}=7.67±0.07 (25±1 C, 1 M HClO{sub 4}). The addition of oxalate to the aqueous phase decreased the distribution ratio, indicating aqueous Hf(IV)-oxalate complex formation. Polynomial fits to the distribution data identified the formation of Hf(ox){sup 2+} and Hf(ox){sub 2(aq)} and their stability constants were measured at 15, 25, and 35 C in 1 M HClO{sub 4}. van't Hoff analysis was used to calculate Δ{sub r}G, Δ{sub r}H, and Δ{sub r}S for these species. Stability constants were observed to increase at higher temperature, an indication that Hf(IV)-oxalate complexation is endothermic and driven by entropy.

  4. Iron(3) chloride interaction with zirconium and hafnium tetrahalides

    International Nuclear Information System (INIS)

    Berdonosov, S.; Kharisov, B.I.; Melikhov, I.V.

    1988-01-01

    Using FeCl 3 , labelled with 36 Cl radionuclide, it is shown, that during reaction between FeCl 3 and MCl (M=Zr, Hf) resulting in Cl 2 splitting-off and FeMCl 6 formation, chlorine is splitted from MCl 4 . From the analysis of Moessbauer spectra and visual observations it follows, that reaction between FeCl 3 and MBr 4 starts at 50 deg C temperature, whereupon bromine and FeMCl 3 Br 3 compounds are formed. Considerations about the possible mechanism of reactions between FeCl 3 and MCl 4 or MBr 4 are proposed

  5. Cesium hafnium chloride scintillator coupled with an avalanche photodiode photodetector

    Czech Academy of Sciences Publication Activity Database

    Kurosawa, S.; Kodama, S.; Yokota, Y.; Horiai, T.; Yamaji, A.; Shoji, Y.; Král, Robert; Pejchal, Jan; Ohashi, Y.; Kamada, K.; Nikl, Martin; Yoshikawa, A.

    2017-01-01

    Roč. 12, Feb (2017), s. 1-8, č. článku C02042. ISSN 1748-0221 Grant - others:AV ČR(CZ) JSPS-17-18 Program:Bilaterální spolupráce Institutional support: RVO:68378271 Keywords : gamma detectors * scintillators and scintillating fibres * scintillators * scintillation and light emission processes Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.220, year: 2016

  6. Spectroscopy of very neutron-deficient hafnium and tungsten isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dracoulis, G D; Fabricius, B; Davidson, P M [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics; Macchiavelli, A O; Oliviera, J; Burde, J; Stephens, F; Deleplanque, M A [Lawrence Berkeley Lab., CA (United States)

    1992-08-01

    Level schemes of the very neutron-deficient isotopes {sup 158}Hf and {sup 162}W have been identified, and that for {sup 164}W extended. Alignment of the H{sub 9/2} neutrons is suggested. (author). 12 refs., 7 figs.

  7. Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films

    National Research Council Canada - National Science Library

    Blasy, Bryan D

    2008-01-01

    ... retains monoclinic local symmetery for all levels of doping. Current as a function of voltage experiments identified the films as having poor diode characteristics with high leakage current in the forward bias region...

  8. Crystal structures of superconducting sodium intercalates of hafnium nitride chloride

    International Nuclear Information System (INIS)

    Oro-Sole, J.; Frontera, C.; Beltran-Porter, D.; Lebedev, O.I.; Van Tendeloo, G.; Fuertes, A.

    2006-01-01

    Sodium intercalation compounds of HfNCl have been prepared at room temperature in naphtyl sodium solutions in tetrahydrofuran and their crystal structure has been investigated by Rietveld refinement using X-ray powder diffraction data and high-resolution electron microscopy. The structure of two intercalates with space group R3-bar m and lattice parameters a=3.58131(6)A, c=57.752(6)A, and a=3.58791(8)A, c=29.6785(17)A is reported, corresponding to the stages 2 and 1, respectively, of Na x HfNCl. For the stage 2 phase an ordered model is presented, showing two crystallographically independent [HfNCl] units with an alternation of the Hf-Hf interlayer distance along the c-axis, according with the occupation by sodium atoms of one out of two van der Waals gaps. Both stages 1 and 2 phases are superconducting with critical temperatures between 20 and 24K, they coexist in different samples with proportions depending on the synthesis conditions, and show a variation in c spacing that can be correlated with the sodium stoichiometry. High-resolution electron microscopy images of the host and intercalated samples show bending of the HfNCl bilayers as well as stacking faults in some regions, which coexist in the same crystal with ordered domains

  9. Elastic and thermodynamic properties of zirconium- and hafnium ...

    Indian Academy of Sciences (India)

    2018-02-02

    Feb 2, 2018 ... ties. The volume optimization curves (both LDA and GGA) for binary Rh3V, Rh3Zr and Rh3Hf compounds are shown in ... the strength of covalent bonding of the given material. ..... Bulk modulus is correlated with binding energy or cohesive energy of atoms, since it is a measure of average atomic bond.

  10. High-spin nuclear target of 178m2Hf: creation and nuclear reaction studies

    International Nuclear Information System (INIS)

    Oganessyan, Yu.Ts.; Karamyan, S.A.; Gangrskij, Yu.P.

    1993-01-01

    A long-lived (31 years) four-quasiparticle isomer 178m 2 Hf(I,K π =16,16 + ) was produced in microweight quantities using the nuclear reaction 176 Yb( 4 He, 2n). Methods of precision chemistry and mass-separation for the purification of the produced Hf material have been developed. Thin targets of isomeric hafnium-178 on carbon backings were prepared and used in experiments on a neutron, proton and deuteron beams. First results on nuclear reactions on a high-spin exotic target were obtained. Experiments on electromagnetic interactions of the isomeric hafnium using methods of the collinear laser spectroscopy as well as of the nuclear orientation of hafnium implanted into a crystalline media were started. 11 refs.; 11 figs.; 2 tabs

  11. Separation of magnesium from magnesium chloride and zirconium and/or hafnium subchlorides in the production of zirconium and/or hafnium sponge metal

    International Nuclear Information System (INIS)

    Abodishish, H.A.M.; Adams, R.J.; Kearl, S.R.

    1992-01-01

    This patent describes the producing of a refractory metal wherein a sponge refractory metal is produced as an intermediate product by the use of magnesium with the incidental production of magnesium chloride, and wherein residual magnesium is separated from the magnesium chloride and from refractory metal to a vacuum distillation step which fractionally distills the magnesium, the magnesium chloride, and the metal sub-chlorides; the steps of: recovering fractionally distilled vapors of magnesium chloride and metal sub-chlorides from a sponge refractory metal; separately condensing the vapors as separately recovered; and recycling the separately recovered magnesium at a purity of at least about 96%

  12. Godiva and Juliet Diagnostics CED-1 (IER-176)

    Energy Technology Data Exchange (ETDEWEB)

    Scorby, J C

    2011-12-21

    A suite of diagnostics are being proposed for use in the Juliet experiment (IER-128). In order to calibrate and test the diagnostics prior to use, the LLNL calibration facility and Godiva pulsed reactor will be used to provide intense sources of neutrons and gammas. Due to the similarities of the Godiva and Juliet radiation fields, the diagnostics being developed and tested for Juliet can also play an on-going role in diagnostics for Godiva as well as, perhaps, other critical assembly experiments. Similar work is also being conducted for IER-147 for the purpose of characterizing the Godiva radiation field in support of an upcoming international nuclear accident dosimetry exercise. Diagnostics developed and fielded under IER-147 can provide valuable data with respect to the neutron and gamma energy spectrums in the vicinity of Godiva which is relevant to the calibration of Juliet diagnostics.

  13. 37 CFR 1.76 - Application data sheet.

    Science.gov (United States)

    2010-07-01

    ... includes the correspondence address, which may be indicated by reference to a customer number, to which... title of the invention, a suggested classification, by class and subclass, the Technology Center to... application, the type of application (e.g., utility, plant, design, reissue, provisional), whether the...

  14. 46 CFR 176.402 - Initial inspection for certification.

    Science.gov (United States)

    2010-10-01

    ..., spars, rigging, sails, piping, main and auxiliary machinery, pressure vessels, steering apparatus... make the vessel available for all applicable inspections discussed in this paragraph, and in Subpart H...

  15. 46 CFR 176.404 - Subsequent inspections for certification.

    Science.gov (United States)

    2010-10-01

    ..., and on a sailing vessel, rigging and sails. The owner or operator must conduct all tests as required by the OCMI, and make the vessel available for all specific inspections and drills required by...

  16. All projects related to | Page 176 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Region: Cambodia, Far East Asia, Central Asia, South Asia ... assumed that the cost of tobacco-related disease to national economies and households is ... An investigation into the determinants of business performance in Francophone Africa.

  17. 40 CFR 180.176 - Mancozeb; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... Asparagus (negligible residue) 0.1 Banana 4.0 Banana, pulp 0.5 Barley, bran 20 Barley, flour 20 Barley..., straw 25 Onion, bulb 0.5 Papaya (whole fruit with no residue present in the edible pulp after the peel...

  18. 46 CFR 160.176-15 - Production tests and inspections.

    Science.gov (United States)

    2010-10-01

    ... known weight and winch, (B) a scale, winch, and fixed anchor, or (C) a tensile test machine that is... laboratory inspector tests and inspects the lot; (ii) Perform required testing of each incoming lot of... produced the components used in the lifejacket. (d) Samples. (1) Samples used in testing and inspections...

  19. 49 CFR 176.600 - General stowage requirements.

    Science.gov (United States)

    2010-10-01

    ... POISON label, being transported on a vessel, must be stowed clear of living quarters and any ventilation ducts serving living quarters and separated from foodstuffs, except when the hazardous materials and the.... (c) Each package bearing a POISON label displaying the text “PG III” or bearing a “PG III” mark...

  20. 49 CFR 176.800 - General stowage requirements.

    Science.gov (United States)

    2010-10-01

    ... must be stowed clear of living quarters, and away from foodstuffs and cargo of an organic nature. (b) A...) which also bears a FLAMMABLE LIQUID label must be stowed away from all sources of heat and ignition...

  1. 40 CFR 63.176 - Quality improvement program for pumps.

    Science.gov (United States)

    2010-07-01

    ... type (e.g., piston, horizontal or vertical centrifugal, gear, bellows); pump manufacturer; seal type... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Quality improvement program for pumps... improvement program for pumps. (a) In Phase III, if, on a 6-month rolling average, the greater of either 10...

  2. Low lying magnetic dipole strength distribution in 176Hf

    International Nuclear Information System (INIS)

    Kuliev, A. A.; Ertugral, F.; Yakut, H.; Bektasoglu, M.; Guliyev, E.

    2006-01-01

    In this study the scissors mode 1 + states are systematically investigated within the rotational invariant Quasiparticle Random Phase Approximation (QRPA) for 1 76Hf isotopes. We consider the 1 + vibrations generated by the isovector spin-spin interactions and the isoscalar (h 0 ) and isovector (h 1 ) quadrupole type separable forces restoring the broken symmetry by a deformed mean field. It has been shown that restoration of the broken rotational symmetry of the Hamiltonian essentially decreases the B(M1) value of the low lying 1 + states and increases the collectivization of the scissors mode excitations in the spectroscopic energy region. Agreement between the calculated mean excitation energies as well as the summed B(M1) value of the scissors mode excitations and the available experimental data of 1 76Hf is rather good. For instance, distributions of the calculated B(M1) transition strengths in the 1 76 Hf isotopes with respect to K π =1 + excitations is represented in Figure. Thus, we see that the models which use the Hamiltonian with broken rotational symmetry strongly overestimate the M1 strength at low energy. These results indicate an importance of the models which are free from the low-energy spurious states. The marked differences between the results for 1 + states, calculated in rotational invariant (RI) and non-rotational invariant (NRI) model indicate the importance of the approaches which are free from spurious low-energy solutions. A separation of the rotational state from the 1 + states changes somewhat the distribution of the B(M1) strength in the spectroscopic energy region and increases the fragmentation of the scissors mode 1 + excitations in agreement with the experimental data

  3. What we do | Page 176 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    AIDS Review 2005 : What's Cooking? ... de la Información - REDIS/DIRSI) is a multidisciplinary network that supports effective participation in ... Middle East, North Of Sahara, South Of Sahara, Central Asia, Far East Asia, South Asia ... consumer goods, marketing services, financial services, and other goods and services.

  4. Dicty_cDB: CHQ176 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available vv*lipqsilmi tmpvqlmhvqkkvv*lilqsilmitmlvpltpvhhqlafptpqltvmivihvp*thvqiq pvvatlqsmlmiiihvl*ihvpnqqvslipqsm*...lqsmlmiiihvpsmpvpnqqvllipqsm*mittnvqlmhvpkkvv*lipqsilmi tmpvqlmhvqkkvv*lilqsilmitmlvpltpvhhqlafptpqltvmivihv

  5. 32 CFR 176.35 - HUD's review of the application.

    Science.gov (United States)

    2010-07-01

    ... other existing housing, social service, community economic, or other development plans adopted by the... to the expressed interest and requests of representatives of the homeless, whether the application... communities in the vicinity of the installation. (2) Impact of notices of interest. Takes into consideration...

  6. 46 CFR 160.176-13 - Approval Tests.

    Science.gov (United States)

    2010-10-01

    ... paragraph (b)(1) of this section is repeated with each subject wearing an insulated, hooded parka and gloves... and in the second test, parka and gloves. (c) Inflation Testing. No second stage donning is allowed in... platform using only his or her hands on the top of the platform as an aid and without pushing off of the...

  7. 21 CFR 176.120 - Alkyl ketene dimers.

    Science.gov (United States)

    2010-04-01

    ..., processing, preparing, treating, packaging, transporting, or holding food, subject to the provisions of this... paperboard. (c) The alkyl ketene dimers may be used in the form of an aqueous emulsion which may contain...

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    International Development Research Centre (IDRC) Digital Library (Canada)

    Community Based Natural Resource Management in the Greater Limpopo Trans ... Foreign Direct Investment Behaviour in Low and Middle Income Countries ... Central Asia, Far East Asia, South Asia, Cambodia, China, Indonesia, Viet Nam, ...

  9. 49 CFR 176.805 - On deck stowage.

    Science.gov (United States)

    2010-10-01

    ... for leakage from any package to drain away from other cargo into an overboard scupper or freeing port... stowage is not practical, sufficient clean dry sand must be placed under and around the lower tier of...

  10. 21 CFR 176.200 - Defoaming agents used in coatings.

    Science.gov (United States)

    2010-04-01

    ...-(Dinonylphenyl)-ω-hydroxy-poly(oxy-1,2-ethanediyl), containing 7 to 24 moles of ethylene oxide per mole of... palmitate Mineral oil Mustardseed oil, sulfated, ammonium, potassium, or sodium salt Myristyl alcohol... the intended effect, which is to prevent or control the formation of foam. (2) The defoaming agents...

  11. 7 CFR 17.6 - Discounts, fees, commissions and payments.

    Science.gov (United States)

    2010-01-01

    ... the supplier; (ii) Give the supplier a competitive advantage in relation to other potential suppliers... anything given in return for any consideration, services, or benefits received or to be received. (a... acted as a selling agent to obtain a contract even though the payment may be for services performed that...

  12. 1935 15' Quad #176 Aerial Photo Mosaic Index

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Aerial Photo Reference Mosaics contain aerial photographs that are retrievable on a frame by frame basis. The inventory contains imagery from various sources that...

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    This knowledge can be used as a tool for addressing pressing global challenges. We share ... Middle East, Central Asia, Far East Asia, South Asia, Peru, South Africa ... Foreign Direct Investment Behaviour in Low and Middle Income Countries.

  14. Quantitative microanalysis of hafnium - zirconium system by X-ray fluorescence

    International Nuclear Information System (INIS)

    Majid, C.A.; Hussain, M.A.; Saeed, K.

    1986-01-01

    X-ray fluorescence technique has been used for the analysis of Hf in the presence of Zr by developing a method. In this method the spectral interference of Hf lines by Zr is eliminated completely and the Hf detection is accomplished using the most efficient Li line of its L-series. The principle of the method is based on the extinction properties of crystals for some orders of reflection. Ge(III) is used as the analyzing crystal. This method can be used accurately to detect Hf in any concentration of Zr at least from about 20 ppm to 100%. Also no information about the expected range of the analyte sample, is required in advance. (authors)

  15. X-Ray fluorescence of microquantities of hafnium in zirconium by precipitation as thin film

    International Nuclear Information System (INIS)

    Vigoda de Leyt, Dora; Caridi, A.F.; Deibe, Jorge

    1988-01-01

    The importance of Zr and Hf in the nuclear industry represents and increasing need for the development of reliable chemical methods to determine Hf traces in Zr matrix. A precipitation method in amoniacal medium was developed. A thin film is obtained where matrix effects are absent or minimized. Hf in the range of 5-70.10 -9 Kg in a 5.10 -6 Kg Zr matrix was studied. Fluorescence Hf Lα and Hf Lβ X-rays are excited by a W-anode tube 17 kV-25mA and 50kV-25mA. Radiation scattered by the tube was used as internal standard. Bartlett criterion was used for the regression analysis. Determination limit was fixed in 5±4. 10 -9 Kg Hf at a 95 % probability. (Author) [es

  16. Hafnium-tungsten chronometry of angrites and the earliest evolution of planetary objects

    DEFF Research Database (Denmark)

    Markowski, A.; Quitté, G.; Kleine, T.

    2007-01-01

    Angrites are amongst the oldest basalts in the solar system and their origins are enigmatic, some even proposing the planet Mercury as the parent body (APB). Whatever their exact provenance their chronometry provides insights into early stages of planetary melting and differentiation. We present...... various short-lived chronometers provides evidence that Al, Mn and Hf were homogeneously distributed in the solar nebula, although we cannot rule out the possibility of local small heterogeneities. Contrary to recent proposals, the data are also consistent with the previously determined age of the solar...... for such late melting and core formation are unclear. Quenched angrites are coeval with non-magmatic IAB iron meteorites and CB chondrules at ~ 4562 Ma. However, demonstration of a genetic link between angrite melting and impact events must await the acquisition of still higher resolution chronometry....

  17. Pressure-dependence of the phase transitions and thermal expansion in zirconium and hafnium pyrovanadate

    Energy Technology Data Exchange (ETDEWEB)

    Gallington, Leighanne C.; Hester, Brett R.; Kaplan, Benjamin S. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332‐0400 (United States); Wilkinson, Angus P., E-mail: angus.wilkinson@chemistry.gatech.edu [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332‐0400 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332‐0245 (United States)

    2017-05-15

    Low or negative thermal expansion (NTE) has been previously observed in members of the ZrP{sub 2}O{sub 7} family at temperatures higher than their order-disorder phase transitions. The thermoelastic properties and phase behavior of the low temperature superstructure and high temperature negative thermal expansion phases of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} were explored via in situ variable temperature/pressure powder x-ray diffraction measurements. The phase transition temperatures of ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} exhibited a very strong dependence on pressure (∼700 K GPa), with moderate compression suppressing the formation of their NTE phases below 513 K. Compression also reduced the magnitude of the coefficients of thermal expansion in both the positive and negative thermal expansion phases. Additionally, the high temperature NTE phase of ZrV{sub 2}O{sub 7} was found to be twice as stiff as the low temperature positive thermal expansion superstructure (24 and 12 GPa respectively). - Graphical abstract: The temperature at which ZrV{sub 2}O{sub 7} transforms to a phase displaying negative thermal expansion is strongly pressure dependent. The high temperature form of ZrV{sub 2}O{sub 7} is elastically stiffer than the low temperature form. - Highlights: • The order-disorder phase transition temperatures in ZrV{sub 2}O{sub 7} and HfV{sub 2}O{sub 7} are strongly pressure dependent (∼700 K.GPa). • The high temperature (disordered) phase of ZrV{sub 2}O{sub 7} is much stiffer than the ambient temperature (ordered) phase. • Compression reduces the magnitude of the negative thermal expansion in the high temperature phase of ZrV{sub 2}O{sub 7}.

  18. Interaction of chelate cyclopentadienyl compounds of zirconium and hafnium with bromine

    International Nuclear Information System (INIS)

    Brajnina, Eh.M.; Minacheva, M.Kh.

    1975-01-01

    Interaction of bromine with Zr and Hf dibenzoylmethane (DBM) compounds of following type: (DBM) 4 M, CpM(DBM) 3 and Cp 2 M(DBM) 2 leads to the formation of (DBM) 2 MBr 2 , (DBM) 3 MBr and CpZr(DBM) 2 Br in the rations which depend on the conditions of the reaction (Cp=C 5 H 5 )

  19. Investigation of Hafnium oxide/Copper resistive memory for advanced encryption applications

    Science.gov (United States)

    Briggs, Benjamin D.

    The Advanced Encryption Standard (AES) is a widely used encryption algorithm to protect data and communications in today's digital age. Modern AES CMOS implementations require large amounts of dedicated logic and must be tuned for either performance or power consumption. A high throughput, low power, and low die area AES implementation is required in the growing mobile sector. An emerging non-volatile memory device known as resistive memory (ReRAM) is a simple metal-insulator-metal capacitor device structure with the ability to switch between two stable resistance states. Currently, ReRAM is targeted as a non-volatile memory replacement technology to eventually replace flash. Its advantages over flash include ease of fabrication, speed, and lower power consumption. In addition to memory, ReRAM can also be used in advanced logic implementations given its purely resistive behavior. The combination of a new non-volatile memory element ReRAM along with high performance, low power CMOS opens new avenues for logic implementations. This dissertation will cover the design and process implementation of a ReRAM-CMOS hybrid circuit, built using IBM's 10LPe process, for the improvement of hardware AES implementations. Further the device characteristics of ReRAM, specifically the HfO2/Cu memory system, and mechanisms for operation are not fully correlated. Of particular interest to this work is the role of material properties such as the stoichiometry, crystallinity, and doping of the HfO2 layer and their effect on the switching characteristics of resistive memory. Material properties were varied by a combination of atomic layer deposition and reactive sputtering of the HfO2 layer. Several studies will be discussed on how the above mentioned material properties influence switching parameters, and change the underlying physics of device operation.

  20. Influence of the oxygen/argon ratio on the properties of sputtered hafnium oxide

    International Nuclear Information System (INIS)

    Pereira, L.; Barquinha, P.; Fortunato, E.; Martins, R.

    2005-01-01

    In this work we have focused our attention on the role of the gas mixture (O 2 /Ar) used during HfO 2 thin film processing by r.f. magnetron sputtering, to produce dielectrics with suitable characteristics to be used as gate dielectric. Increasing the O 2 /Ar ratio from 0 to 0.2, the films properties (optical gap, permittivity, resistivity and compactness) are improved. At these conditions, films with a band gap around 5 eV were produced, indicating a good stoichiometry. Also the flat band voltage has a reduction of almost three times indicating also a reduction of the same order on the fixed charge density at the semiconductor-insulator interface. The dielectric constant is around 16 which is very good, since the surface of the silicon where the HfO 2 films were deposited contains a SiO 2 layer of about 3 nm that gives an effective dielectric constant above 20, close to the HfO 2 stoichiometric value (∼25). Further increase on the O 2 /Ar ratio does not produce significant improvements

  1. Structure and Optical Properties of Nanocrystalline Hafnium Oxide Thin Films (PostPrint)

    Science.gov (United States)

    2014-09-01

    sputter-deposition. A large band gap coupled with low absorption provide optical transparency over a broad range in the electromagnetic spectrum; HfO2...k) in the middle of the visible spec- trum, and C influences n(k) to a greater extent in shorter wave - lengths [31]. Note that this principle behind...Approved for publicnanocrystalline HfO2 films crystallize in monoclinic structure. Fur - thermore, increasing Ts results in improved structural order and

  2. The Juvenile Hafnium Isotope Signal as a Record of Supercontinent Cycles

    Science.gov (United States)

    Gardiner, Nicholas J.; Kirkland, Christopher L.; van Kranendonk, Martin J.

    2016-12-01

    Hf isotope ratios measured in igneous zircon are controlled by magmatic source, which may be linked to tectonic setting. Over the 200-500 Myr periodicity of the supercontinent cycle - the principal geological phenomenon controlling prevailing global tectonic style - juvenile Hf signals, i.e. most radiogenic, are typically measured in zircon from granites formed in arc settings (crustal growth), and evolved zircon Hf signals in granites formed in continent-collision settings (crustal reworking). Interrogations of Hf datasets for excursions related to Earth events commonly use the median value, however this may be equivocal due to magma mixing. The most juvenile part of the Hf signal is less influenced by crustal in-mixing, and arguably a more sensitive archive of Earth’s geodynamic state. We analyze the global Hf dataset for this juvenile signal, statistically correlating supercontinent amalgamation intervals with evolved Hf episodes, and breakup leading to re-assembly with juvenile Hf episodes. The juvenile Hf signal is more sensitive to Pangaea and Rodinia assembly, its amplitude increasing with successive cycles to a maximum with Gondwana assembly which may reflect enhanced subduction-erosion. We demonstrate that the juvenile Hf signal carries important information on prevailing global magmatic style, and thus tectonic processes.

  3. As-cast structure refinement of Ti-46Al alloy by hafnium and boron additions

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2009-05-01

    Full Text Available The infl uence of Hf and B on the solidifi cation structure of cast Ti-46Al alloys was investigated. The results show that the coupling effect of Hf and B changes the solidifi cation structure morphology and strongly refi nes the grain size. When the Hf+B contents were increased from 0 + 0.0 to 3 + 0.2, 5 + 0.6 and 7 + 1.0 (in at. %, the solidification structure morphology changed from coarse columnar dendrite to fine columnar dendrite, then to equiaxed dendrite, and further to fi ne near granular grain whilst the average grain size decreased to 20 μm. It is concluded that the columnar dendrite refinement is due to the effect of Hf and B on the decrease of Al diffusion coeffi cient in the melt. The fi ne near granular grain formation is attributed to the combined constitutional supercooling formed by Al and B segregation that is strengthened by Hf and B additions at the solid/liquid interface during solidifi cation, and the TiB2 precipitates acting as heterogeneous nuclei

  4. Metal-Element Compounds of Titanium, Zirconium, and Hafnium as Pyrotechnic Fuels

    Science.gov (United States)

    2015-05-04

    59 Ti3O5 (s, 59.9), K (g, 19.9), N2 (g, 8.2), H2O (g, 5.2), KOH (g, 4.0) TiB2 2868 26 / 74 TiO2 (l, 16.3), Ti2O3 (l, 8.7), KBO2 (g, 56.0), N2 (g...Borate Glasses – Structural Studies with NMR and Raman Spectroscopies. J. Phys. Chem. 100, 16720-16728. 9. Massis, T. M. (1996) New Explosive

  5. Characterization of the superconducting state in hafnium hydride under high pressure

    Science.gov (United States)

    Duda, A. M.; Szewczyk, K. A.; Jarosik, M. W.; Szcześniak, K. M.; Sowińska, M. A.; Szcześniak, D.

    2018-05-01

    The hydrogen-rich compounds at high pressure may exhibit notably high superconducting transition temperatures. In the paper, we have calculated the basic thermodynamic parameters of the superconducting state in two selected phases of HfH2 hydride under high-pressure respectively at 180 GPa for Cmma and 260 GPa for P21 / m . Calculations has been conducted in the framework of the Eliashberg formalism. In particular, we have determined the values of the critical temperature (TC) to be equal to 8 K and 13 K for the Cmma and P21 / m phases, respectively. Moreover, we have estimated other thermodynamic properties such as the order parameter (Δ (T)) , the thermodynamic critical field (HC (T)) , and the specific heat for the normal (CN) and superconducting (CS) state. Finally, we have shown that the characteristic ratios: RΔ = 2 Δ (0) /kBTC and RC = ΔC (TC) /CN (TC) , which are related to the above thermodynamic functions, slightly differ from the predictions of the Bardeen-Cooper-Schrieffer theory due to the strong-coupling and retardation effects.

  6. Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

    International Nuclear Information System (INIS)

    Rea, K.E.; Viswanathan, V.; Kruize, A.; Hosson, J.Th.M. de; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.

    2008-01-01

    Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured thermo-mechanical components. Spray drying of powder feedstock appears to have a significant effect on the improved mechanical properties of the bulk nanocomposite. The reported elastic modulus of the nanocomposite nearly doubles due to the presence of HfC nano particulates in the W matrix. High resolution transmission electron microscopy (HRTEM) revealed the retention of nanostructures at the select process conditions and is correlated with the enhanced mechanical properties of the nanocomposite

  7. Spectroscopic and structural investigation of undoped and Er{sup 3+} doped hafnium silicate layers

    Energy Technology Data Exchange (ETDEWEB)

    Khomenkova, L., E-mail: khomen@ukr.net [CIMAP CEA/CNRS/ENSICAEN/UCBN, 6 Blvd. Maréchal Juin, 14050 Caen Cedex 4 (France); V. Lashkaryov Institute of Semiconductor Physics at NASU, 41 Pr. Nauky, Kyiv 03028 (Ukraine); An, Y.-T. [CIMAP CEA/CNRS/ENSICAEN/UCBN, 6 Blvd. Maréchal Juin, 14050 Caen Cedex 4 (France); Khomenkov, D. [Taras Shevchenko National University of Kyiv, Faculty of Physics, 4 Pr. Hlushkov, Kyiv 03022 (Ukraine); Portier, X.; Labbé, C.; Gourbilleau, F. [CIMAP CEA/CNRS/ENSICAEN/UCBN, 6 Blvd. Maréchal Juin, 14050 Caen Cedex 4 (France)

    2014-11-15

    This paper demonstrates the functionality of radio-frequency magnetron sputtering for the fabrication of undoped and Er-doped Si-rich-HfO{sub 2} films with specific structural and spectroscopic properties. The effect of post-deposition treatment on film properties was investigated by means of Fourier-transform infrared spectroscopy, Raman scattering and photoluminescence methods, as well as Transmission Electron microscopy. It was observed that annealing treatment at 850–1000 °C causes phase separation process and the formation of HfO{sub 2}, SiO{sub 2} and pure Si phases. This process stimulates also an intense light emission in the 700–950-nm spectral range under broad band excitation. The phase separation mechanism as well as the nature of radiative transitions were discussed. Photoluminescence was ascribed to carrier recombination in silicon clusters and host defects. The appearance of silicon clusters was also confirmed by the comparison of luminescent properties of pure HfO{sub 2}, SiO{sub 2}, Si-rich-HfO{sub 2} and Si-rich-SiO{sub 2} films. Additional argument for Si clusters’ formation was obtained under investigation of Er-doped Si-rich HfO{sub 2} films. These latter demonstrated 1.54-µm Er{sup 3+} luminescence under non-resonant excitation originating from an energy transfer from Si clusters towards Er{sup 3+} ions.

  8. Electric field and temperature scaling of polarization reversal in silicon doped hafnium oxide ferroelectric thin films

    International Nuclear Information System (INIS)

    Zhou, Dayu; Guan, Yan; Vopson, Melvin M.; Xu, Jin; Liang, Hailong; Cao, Fei; Dong, Xianlin; Mueller, Johannes; Schenk, Tony; Schroeder, Uwe

    2015-01-01

    HfO 2 -based binary lead-free ferroelectrics show promising properties for non-volatile memory applications, providing that their polarization reversal behavior is fully understood. In this work, temperature-dependent polarization hysteresis measured over a wide applied field range has been investigated for Si-doped HfO 2 ferroelectric thin films. Our study indicates that in the low and medium electric field regimes (E < twofold coercive field, 2E c ), the reversal process is dominated by the thermal activation on domain wall motion and domain nucleation; while in the high-field regime (E > 2E c ), a non-equilibrium nucleation-limited-switching mechanism dominates the reversal process. The optimum field for ferroelectric random access memory (FeRAM) applications was determined to be around 2.0 MV/cm, which translates into a 2.0 V potential applied across the 10 nm thick films

  9. The Rayleigh law in silicon doped hafnium oxide ferroelectric thin films

    International Nuclear Information System (INIS)

    Guan, Yan; Liu, Xiaohua; Zhou, Dayu; Xu, Jin; Cao, Fei; Dong, Xianlin; Mueller, Johannes; Schenk, Tony; Schroeder, Uwe

    2015-01-01

    A wealth of studies have confirmed that the low-field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro-mechanism. Recently, HfO 2 thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub-coercive polarization reversal properties were investigated for 10 nm thick Si-doped HfO 2 thin films. The applicability of the Rayleigh law to ultra-thin ferroelectric films was first confirmed, indicating the existence of a multi-domain structure. Since the grain size is about 20-30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Structure and property evaluation of a vacuum plasma sprayed nanostructured tungsten-hafnium carbide bulk composite

    NARCIS (Netherlands)

    Rea, K. E.; Viswanathan, V.; Kruize, A.; De Hosson, J. Th. M.; O'Dell, S.; McKechnie, T.; Rajagopalan, S.; Vaidyanathan, R.; Seal, S.; O’Dell, S.

    2008-01-01

    Vacuum plasma spray (VPS) forming of tungsten-based metal matrix nanocomposites (MMCs) has shown to be a cost effective and time saving method for the formation of bulk monolithic nanostructured then no-mechanical components. Spray drying of powder feedstock appears to have a significant effect on

  11. Radiation Effects on the Electrical Properties of Hafnium Oxide Based MOS Capacitors

    Science.gov (United States)

    2011-03-01

    evaporator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 12. Copper crucible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21...picture shows the chamber, controls, and pumps. Figure 12. A copper crucible held a cylindrical pellet of the contact metal. An electron beam evaporated

  12. The Rayleigh law in silicon doped hafnium oxide ferroelectric thin films

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Yan; Liu, Xiaohua [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian (China); Zhou, Dayu [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian (China); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu (China); Xu, Jin [Department of Electronic Engineering, Dalian Neusoft University of Information, Dalian (China); Cao, Fei; Dong, Xianlin [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China); Mueller, Johannes [Fraunhofer IPMS-CNT, Dresden (Germany); Schenk, Tony; Schroeder, Uwe [NaMLab gGmbH/TU Dresden (Germany)

    2015-10-15

    A wealth of studies have confirmed that the low-field hysteresis behaviour of ferroelectric bulk ceramics and thin films can be described using Rayleigh relations, and irreversible domain wall motion across the array of pining defects has been commonly accepted as the underlying micro-mechanism. Recently, HfO{sub 2} thin films incorporated with various dopants were reported to show pronounced ferroelectricity, however, their microscopic domain structure remains unclear till now. In this work, the effects of the applied electric field amplitude, frequency and temperature on the sub-coercive polarization reversal properties were investigated for 10 nm thick Si-doped HfO{sub 2} thin films. The applicability of the Rayleigh law to ultra-thin ferroelectric films was first confirmed, indicating the existence of a multi-domain structure. Since the grain size is about 20-30 nm, a direct observation of domain walls within the grains is rather challenging and this indirect method is a feasible approach to resolve the domain structure. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Corrosion of Fe-25 Cr Alloy with microconstituent additions of hafnium and platinum

    International Nuclear Information System (INIS)

    Srinivasan, V.

    1989-01-01

    The study reported was performed with a view to understanding the effects of minor additions of Hf and Pt on the corrosion behavior of a model chromia former, Fe-25Cr. Bulk addition of Hf or Pt was made at 1 wt.% level to the base alloy, Fe-25 Cr, and the experimental alloys were made by an ingot metallurgy route. Coupons were machined from the as-cast rods or forged prismatic bars, and metallographically polished to 1 μ alumina. Multiple samples were exposed to an H 2 /H 2 S/H 2 O/Ar gas mixture at 700 degrees C for times up to 192 hrs. Planar and cross-sections of scales formed on the substrate alloys were examined using a scanning electron microscope with an energy dispersive x-ray spectrometer (SEM/EDAX). A uniform chromia scale formed initially. This scale was broken down locally and slowly by the overgrowth of sulfide rich nodules. The effects of minor additions of Hf or Pt on the growth and breakdown of protective chromia scales are discussed in this paper

  14. High temperature strengthening mechanism of hafnium carbide in a tungsten-rhenium matrix

    International Nuclear Information System (INIS)

    Luo, A.; Shin, K.S.; Jacobson, D.L.

    1991-01-01

    The interrelationship between the testing temperature and HfC strength increment of an arc-melted W-3.6Re-0.4HfC was determined from 1950 K to 2980 K in a vacuum of better than 1.3x10 -5 Pa (10 -7 torr). The present research was focused on the characteristic temperature at which the rapid coarsening of HfC particles occurred and the effect of the second-phase particle size on the high temperature strength properties of this material. It was found that the HfC particle strengthening was effective in a W-Re matrix up to a characteristic temperature of 2450 K in the short-term tensile test. Carbon was found to be the rate-limiting solute in the HfC particle growth. The strength of HfC strengthened alloy at temperature above 0.5 T m is proportional to the square root of particle volume fraction. The yield strengths of W-3.6Re-0.26HfC calculated based on the particle statistical distribution had good agreement with the experimental values from 1950 K to 2980 K. Besides, an addition of 0.26 percent HfC in tungsten resulted in about 28 percent increase in the activation energy of plastic deformation at high temperatures

  15. Precise simultaneous determination of zirconium and hafnium in silicate rocks, meteorites and lunar samples. [Neutron reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P A; Garg, A N; Ehmann, W D [Kentucky Univ., Lexington (USA). Dept. of Chemistry

    1977-01-01

    A precise, sensitive and rapid analytical technique has been developed for the simultaneous determination of Zr and Hf in natural silicate matrices. The technique is based on radiochemical neutron activation analysis and employs a rapid fusion dissolution of the sample and simultaneous precipitation of the Zr-Hf pair with p-hydroxybenzene arsenic acid in an acidic medium. The indicator radionuclides, /sup 95/Zr and /sup 181/Hf, are counted and the /sup 95/Zr activity is corrected for the contribution from U fission. The chemical yields of the radiochemical separation are based on Hf carrier. The yield is determined by reactivation of the processed samples and standards with a /sup 252/Cf isotopic neutron source and by counting the 18.6 sec half-life sup(179m)Hf. The RNAA procedure for Zr and Hf has been shown to be precise and accurate for natural silicate samples, based on replicate analyses of samples containing Zr in the range of 1 ..mu..g/g to over 600 ..mu..g/g. The procedure is relatively rapid with a total chemical processing time of approximately 3 hours. At least 4 samples are processed simultaneously. Ten additional elements (Fe, Cr, Co, Sc, Eu, La, Lu, Ce, Th and Tb) can be determined by direct Ge(Li) spectrometry (INAA) on the samples prior to dissolution for the RNAA determination of Zr and Hf. Corrections for the U fission contribution can be made on the basis of the known U content or from the INAA Th content, based on the relatively constant natural Th/U ratio.

  16. CONVERSION OF D-XYLOSE INTO FURFURAL WITH ALUMINUM AND HAFNIUM PILLARED CLAYS AS CATALYST

    Directory of Open Access Journals (Sweden)

    WILLIAM CORTÉS

    2013-01-01

    Full Text Available El proceso industrial utilizado para la producción de furfural es la deshidratación de pentosas, la cual se lleva a cabo por medio de ácidos minerales, altamente corrosivos y contaminantes como catalizadores. Debido a los efectos ecológicos y toxicológicos asociados a este proceso, y a la dificultad en la separación del producto, el desarrollo de nuevos catalizadores sólidos ácidos ha tenido una significativa expansión en los últimos años. El presente trabajo de investigación se enfocó en la producción de furfural a partir de D-xilosa empleando como catalizadores sólidos ácidos, arcillas pilarizadas con aluminio y hafnio. Después de 4 h de reacción a temperaturas entre 140 y 170 °C, los resultados evidenciaron una conversión entre el 50 y el 80%, mientras que los niveles de selectividad alcanzados estuvieron entre el 40 y el 65%. Finalmente, la estabilidad de los catalizadores fue evaluada por medio de un tratamiento térmico, antes de usarlo de nuevo. En cuatro reacciones consecutivas no fue observada una disminución significativa en la selectividad. En conclusión, las arcillas pilarizadas evidencian ser catalizadores activos, selectivos y estables para la deshidratación de pentosas.

  17. Cavitation resistance of 45 and 2H13 steels laser enriched with silicon carbides and hafnium

    International Nuclear Information System (INIS)

    Skodo, M.; Giren, B.; Cenian, A.

    1999-01-01

    Cavitation resistance of 45 and H13 steels with surface layers enriched with Hf and SiC compounds was investigated. All contamination elements were spread over the samples surfaces and subsequently alloyed with core material by CO 2 laser beam. Cavitation tests carried out at the rotating disk facility revealed multiple - 5 to 10 times - increase of erosion resistance of the processed materials during the incubation period of the destruction. This effect was found not to be decisively linked to obtained microhardness changes. (author)

  18. Iron modified titanium–hafnium binary oxides as catalysts in total oxidation of ethyl acetate

    Czech Academy of Sciences Publication Activity Database

    Tsoncheva, T.; Ivanova, R.; Henych, Jiří; Velinov, N.; Kormunda, M.; Dimitrov, M.; Paneva, D.; Slušná, Michaela; Mitov, I.; Štengl, Václav

    2016-01-01

    Roč. 81, JUN (2016), s. 14-19 ISSN 1566-7367 R&D Projects: GA MŠk LM2015073 Institutional support: RVO:61388980 Keywords : Titania–hafnia binary oxide s * Iron modifications * Support effect * Ethyl acetate oxydation Subject RIV: CA - Inorganic Chemistry Impact factor: 3.330, year: 2016

  19. Creep and Oxidation of Hafnium Diboride Based Ultra High Temperature Ceramics at 1500C

    Science.gov (United States)

    2015-12-01

    word ceramic comes from the Greek word keramos, meaning pottery, but now refers to many classes of materials, including clays , abrasives......these situations, the viscosity of the grain boundary becomes an important factor for the creep rate. 25 When grain elongation accompanies grain

  20. Plasma arc cutting: Microstructural modifications of hafnium cathodes during first cycles

    Energy Technology Data Exchange (ETDEWEB)

    Rotundo, F., E-mail: fabio.rotundo@unibo.it [Dept. of Mechanical Engineering (DIEM), Alma Mater Studiorum, Universita di Bologna, Via Saragozza 8, 40123 Bologna (Italy); Martini, C.; Chiavari, C.; Ceschini, L. [Dept. of Metals Science, Electrochemistry and Chemical Techniques (SMETEC), Alma Mater Studiorum, Universita di Bologna, Viale Risorgimento 4, 40136 Bologna (Italy); Concetti, A.; Ghedini, E.; Colombo, V. [Dept. of Mechanical Engineering (DIEM), Alma Mater Studiorum, Universita di Bologna, Via Saragozza 8, 40123 Bologna (Italy); Dallavalle, S. [Cebora S.p.A., Via Andrea Costa 24, 40057 Cadriano di Granarolo (Italy)

    2012-06-15

    In the present work, the microstructural modifications of the Hf insert in plasma arc cutting (PAC) electrodes operating at 250 A were experimentally investigated during first cycles, in order to understand those phenomena occurring on and under the Hf emissive surface and involved in the electrode erosion process. Standard electrodes were subjected to an increasing number of cutting cycles (CCs) on mild steel plates in realistic operative conditions, with oxygen/air as plasma/shield gas. Microstructural analysis was performed for each electrode at different erosion stages by means of scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and Raman spectroscopy. Electrodes cross sections were also observed by means of optical microscopy (both in bright field and in reflected polarised light) after chemical etching. In the insert, three typical zones were found after cutting: monoclinic HfO{sub 2} layer; thermally-modified transition zone with O{sub 2}-Hf solid solution; unmodified Hf. The erosion cavity and the oxide layer thickness increase with the number of cutting cycles. Macrocracking was observed in the oxide layer, while microcracking and grain growth were detected in the remelted Hf. Moreover, detachment was found at the Hf/Cu interface. Based on thermodynamics and kinetics of the Hf high temperature oxidation, conclusions can be drawn on the erosion mechanism involved. - Highlights: Black-Right-Pointing-Pointer Hf microstructural modifications in cathodes after plasma arc cutting cycles investigated. Black-Right-Pointing-Pointer 3 zones identified after cutting: HfO{sub 2} layer; remelted zone with O{sub 2}-Hf solid solution; unmodified Hf. Black-Right-Pointing-Pointer Hf-based ejections both in arc-on and arc-off phases; erosion cavity deepens with cutting cycles. Black-Right-Pointing-Pointer Detachment at the Hf/Cu interfaces, worsening heat dissipation and oxidation/erosion phenomena. Black-Right-Pointing-Pointer The use of a different current ramp at subsequent erosion stages is suggested.

  1. The high-spin {sup 178m2}Hf isomer: production, chemical and isotopic separations, gamma spectrometry and internal conversion electrons spectrometry; L`isomere de haut spin {sup 178m2}Hf: production, separations chimiques et isotopiques, spectrometrie gamma et spectrometrie d`electrons de conversion interne

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J B

    1993-10-13

    The high-spin isometric state of the nucleus 178Hf is a challenge for new and exotic nuclear physics studies. With its long half-life of 31 years, the production of a reasonable micro-weight quantity, with an isometric to ground state ratio as high as 5 per cent, is now regularly performed by intensive irradiations of ytterbium targets with helium ions of 36 MeV. Using sur-enriched, at 99,998 per cent, ytterbium 176 that we have prepared at the PARIS mass separator, the isomer purity has been improved. Targets of such material but also of enriched stable isotopes of hafnium have been prepared by electro-spraying of methanolic and acetic solutions. By inelastic diffusion of protons and deuton on these targets, the energy of the first state of the rotation band built on the isomer has been measured. Isotopic separations of the isomer have been performed, with a yield greater than 20 per cent, by the use of isotopically pure hafnium 176 as carrier. The separated beam of the mass 178 allowed to record the complete hyperfine spectrum of the isomer and to measure, for the first time, the magnetic dipole moment and the electric quadrupole moment. Isomer targets, implanted in various materials like copper, iron and hafnium monocrystal, provide the opportunity to accurately measure gamma and internal conversion decay of this nuclei and so to precise the multipolarity mixing of all transitions from K=16{sup +} to K=8{sup -}. (author). 49 refs., 47 figs., 11 tabs.

  2. X-ray detection capabilities of plastic scintillators incorporated with hafnium oxide nanoparticles surface-modified with phenyl propionic acid

    Science.gov (United States)

    Hiyama, Fumiyuki; Noguchi, Takio; Koshimizu, Masanori; Kishimoto, Shunji; Haruki, Rie; Nishikido, Fumihiko; Yanagida, Takayuki; Fujimoto, Yutaka; Aida, Tsutomu; Takami, Seiichi; Adschiri, Tadafumi; Asai, Keisuke

    2018-01-01

    We synthesized plastic scintillators incorporated with HfO2 nanoparticles as detectors for X-ray synchrotron radiation. Nanoparticles with sizes of less than 10 nm were synthesized with the subcritical hydrothermal method. The detection efficiency of high-energy X-ray photons improved by up to 3.3 times because of the addition of the nanoparticles. Nanosecond time resolution was successfully achieved for all the scintillators. These results indicate that this method is applicable for the preparation of plastic scintillators to detect X-ray synchrotron radiation.

  3. Reduction of the interfacial trap density of indium-oxide thin film transistors by incorporation of hafnium and annealing process

    Directory of Open Access Journals (Sweden)

    Meng-Fang Lin

    2015-01-01

    Full Text Available The stable operation of transistors under a positive bias stress (PBS is achieved using Hf incorporated into InOx-based thin films processed at relatively low temperatures (150 to 250 °C. The mobilities of the Hf-InOx thin-film transistors (TFTs are higher than 8 cm2/Vs. The TFTs not only have negligible degradation in the mobility and a small shift in the threshold voltage under PBS for 60 h, but they are also thermally stable at 85 °C in air, without the need for a passivation layer. The Hf-InOx TFT can be stable even annealed at 150 °C for positive bias temperature stability (PBTS. A higher stability is achieved by annealing the TFTs at 250 °C, originating from a reduction in the trap density at the Hf-InOx/gate insulator interface. The knowledge obtained here will aid in the realization of stable TFTs processed at low temperatures.

  4. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    International Nuclear Information System (INIS)

    Shimizu, T; Villamayor, M; Helmersson, U; Lundin, D

    2016-01-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar–N 2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N 2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf–N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail. (paper)

  5. Separation of zirconium (Zr) and hafnium (Hf) using solvent mixture of TBP-D_2EHPA and amberlite XAD-16

    International Nuclear Information System (INIS)

    Dwi Biyantoro; I Made Sukarna; Agus Suyanto

    2017-01-01

    The aims of this research were to determine the composition (ratio of extractant and resin) of the SIR which is effective for the separation of Zr and Hf, knowing adsorption equilibrium models Zr and Hf using the SIR, and knowing the most effective adsorption results from SIR weight ratio. The research was conducted by using the SIR method that is impregnating the extractant into the resin. Extractant used is a mixture of TBP and D_2EHPA (1 : 3), the resin used is XAD-16, and the feed used is ZOC. This research was conducted by varying the composition of the SIR, after the result of effective SIR variation. Adsorption process is then performed using the ZOC with SIR. Then filtered, the filtrate was analyzed by XRF. While solids SIR adsorption product was desorbed using sulfuric acid. Then the desorption results were analyzed using XRF spectrometer. Based on calculations, the results of the most effective SIR composition for the separation of Zr-Hf are comparison extractant and resin = 5:5 either for the dry method and wet method, the equilibrium equations for Zr approaching Langmuir equilibrium models while the equilibrium equation for Hf approaching Freundlich equilibrium models which the most effective adsorption results that bait comparison with the SIR = 10 mL : 5 g with β = 0.1831; η Zr = 26.39 % and η Hf = 66.19 % for dry method and β = 0.1557; η Zr = 25.17 % and η Hf = 68.36 % for wet method. From result desorption process was 2 M H_2SO_4. (author)

  6. Effects of carbon and hafnium concentrations in wrought powder-metallurgy superalloys based on nasa 2b-11 alloy

    International Nuclear Information System (INIS)

    Miner, R.V. Jr.

    1976-01-01

    A candidate alloy for advanced-temperature turbine engine disks and four modifications of that alloy with various C and Hf concentrations were produced as cross-rolled disks from prealloyed powder that was hot isostatically compacted. The mechanical properties, microstructures, and phase relations of the alloys are discussed in terms of their C and Hf concentrations. A low-C and high-Hf modification of IIB-11 had the best balance of mechanical properties for service below about 750 C. Because of their finer grain sizes, none of the powder-metallurgy alloys produced had the high-temperature rupture strength of conventionally cast and wrought IIB-11. (Author)

  7. New constraints on the sources and behavior of neodymium and hafnium in seawater from Pacific Ocean ferromanganese crusts

    Science.gov (United States)

    van de Flierdt, T.; Frank, M.; Lee, D.-C.; Halliday, A.N.; Reynolds, B.C.; Hein, J.R.

    2004-01-01

    The behavior of dissolved Hf in the marine environment is not well understood due to the lack of direct seawater measurements of Hf isotopes and the limited number of Hf isotope time-series obtained from ferromanganese crusts. In order to place better constraints on input sources and develop further applications, a combined Nd-Hf isotope time-series study of five Pacific ferromanganese crusts was carried out. The samples cover the past 38 Myr and their locations range from sites at the margin of the ocean to remote areas, sites from previously unstudied North and South Pacific areas, and water depths corresponding to deep and bottom waters. For most of the samples a broad coupling of Nd and Hf isotopes is observed. In the Equatorial Pacific ENd and EHf both decrease with water depth. Similarly, ENd and EHf both increase from the South to the North Pacific. These data indicate that the Hf isotopic composition is, in general terms, a suitable tracer for ocean circulation, since inflow and progressive admixture of bottom water is clearly identifiable. The time-series data indicate that inputs and outputs have been balanced throughout much of the late Cenozoic. A simple box model can constrain the relative importance of potential input sources to the North Pacific. Assuming steady state, the model implies significant contributions of radiogenic Nd and Hf from young circum-Pacific arcs and a subordinate role of dust inputs from the Asian continent for the dissolved Nd and Hf budget of the North Pacific. Some changes in ocean circulation that are clearly recognizable in Nd isotopes do not appear to be reflected by Hf isotopic compositions. At two locations within the Pacific Ocean a decoupling of Nd and Hf isotopes is found, indicating limited potential for Hf isotopes as a stand-alone oceanographic tracer and providing evidence of additional local processes that govern the Hf isotopic composition of deep water masses. In the case of the Southwest Pacific there is evidence that decoupling may have been the result of changes in weathering style related to the buildup of Antarctic glaciation. Copyright ?? 2004 Elsevier Ltd.

  8. Synthesis and spectral properties of axially substituted zirconium(IV) and hafnium(IV) water soluble phthalocyanines in solutions

    International Nuclear Information System (INIS)

    Gerasymchuk, Y.S.; Volkov, S.V.; Chernii, V.Ya.; Tomachynski, L.A.; Radzki, St.

    2004-01-01

    Methods of synthesis of novel water soluble axially substituted Zr(IV) and Hf(IV) phthalocyanines with gallic, 5-sulfosalicyllic, oxalic acids, and methyl ester of gallic acid as axial ligands coordinated to the central atom metal of phthalocyanine are presented. The absorption spectra of complex solutions in various solvents were characterized. The dependence of the spectral red shift from Reichardt's empirical polarity parameter is described. The deviation from the linearity of Beer-Bouguer-Lambert law was investigated for the range of concentration 5x10 -6 to 10x10 -5 M. Fluorescent properties of axially substituted phthalocyaninato metal complexes in DMSO solutions were investigated

  9. High temperature oxidation behavior of hafnium modified NiAl bond coat in EB-PVD thermal barrier coating system

    Energy Technology Data Exchange (ETDEWEB)

    Guo Hongbo; Sun Lidong; Li Hefei [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China); Gong Shengkai [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China)], E-mail: gongsk@buaa.edu.cn

    2008-06-30

    NiAl coatings doped with 0.5 at.% and 1.5 at.% Hf were produced by co-evaporation of NiAl and Hf ingots by electron beam physical vapor deposition (EB-PVD), respectively. The addition of 0.5 at.% Hf significantly improved the cyclic oxidation resistance of the NiAl coating. The TGO layer in the 1.5 at.% Hf doped NiAl coating is straight; while that in the 0.5 at.% Hf doped coating became undulated after thermal cycling. The doped NiAl thermal barrier coatings (TBCs) revealed improved thermal cycling lifetimes at 1423 K, compared to the undoped TBC. Failure of the 0.5 at.% Hf doped TBC occurred by cracking at the interface between YSZ topcoat and bond coat, while the 1.5 at.% Hf doped TBC cracked at the interface between bond coat and substrate.

  10. Radiochemical separations of hafnium, tantalum, and germanium from tungsten and selenium irradiated by 14 MeV neutrons

    International Nuclear Information System (INIS)

    Blachot, J.; Benabed, A.; Herment, J.; Monnand, E.

    1968-01-01

    Radiochemical separations of Hf, Ta and Ge from W and Se respectively, after 14 MeV-neutron irradiation. A new isotope: 79 Ge with a half-live of 50 ± 5 s and emitter of a 230 keV γ transition is observed. (authors) [fr

  11. Study of the heat conductivity of double and triple disordered solid solutions in the titanium-zirconium-hafnium system

    Energy Technology Data Exchange (ETDEWEB)

    Zarichnyak, Yu.P.; Lisnenko, T.A.

    1977-10-01

    Measurements are presented of the heat physical properties of trinary alloys in the system Ti-Zr-Hf. The possibility is shown of summarizing the results of the measurement and prediction of the heat conductivity of trinary continuous disordered solid solutions. Comparison of calculated results with experimental data shows that the method of modeling of the structure and prediction of heat conductivity suggested yields good qualitative and quantitative agreement throughout the entire range of change of concentration of the components. The maximum disagreement between calculated and experimental results is about 10%. 8 references, 2 figures, 1 table.

  12. Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts.

    Science.gov (United States)

    Makio, Haruyuki; Prasad, Aitha Vishwa; Terao, Hiroshi; Saito, Junji; Fujita, Terunori

    2013-07-07

    Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.

  13. Measurements of 14-MeV neutron cross-sections for the production of isomeric states in hafnium isotopes

    International Nuclear Information System (INIS)

    Patrick, B.H.; Sowerby, M.G.; Wilkins, C.G.; Russen, L.C.

    1990-01-01

    The cross sections for the production of isomeric states in the reactions 179 Hf(n,2n) 178m2 Hf, 180 Hf(n,2n) 179m2 Hf, 179 Hf(n,n') 179m2 Hf with 14 MeV neutrons have been measured and compared with the theoretical ones. 4 refs, 3 figs, 4 tabs

  14. Processing, Structure and High Temperature Oxidation Properties of Polymer-Derived and Hafnium Oxide Based Ceramic Systems

    Science.gov (United States)

    Terauds, Kalvis

    Demands for hypersonic aircraft are driving the development of ultra-high temperature structural materials. These aircraft, envisioned to sustain Mach 5+, are expected to experience continuous temperatures of 1200--1800°C on the aircraft surface and temperatures as high as 2800°C in combustion zones. Breakthroughs in the development of fiber based ceramic matrix composites (CMCs) are opening the door to a new class of high-tech UHT structures for aerospace applications. One limitation with current carbon fiber or silicon carbide fiber based CMC technology is the inherent problem of material oxidation, requiring new approaches for protective environmental barrier coatings (EBC) in extreme environments. This thesis focuses on the development and characterization of SiCN-HfO2 based ceramic composite EBC systems to be used as a protective layer for silicon carbide fiber based CMCs. The presented work covers three main architectures for protection (i) multilayer films, (ii) polymer-derived HfSiCNO, and (iii) composite SiCN-HfO 2 infiltration. The scope of this thesis covers processing development, material characterization, and high temperature oxidation behavior of these three SiCN-HfO2 based systems. This work shows that the SiCN-HfO 2 composite materials react upon oxidation to form HfSiO4, offering a stable EBC in streaming air and water vapor at 1600°C.

  15. The effect of hafnium content on the transformation temperatures of Ni49Ti51-xHfx shape memory alloys

    International Nuclear Information System (INIS)

    Angst, D.R.; Thoma, P.E.; Kao, M.Y.

    1995-01-01

    Ternary alloys of NiTiHf, having higher transformation temperatures than binary NiTi shape memory alloys, have been produced and analyzed. Beginning with a base composition of Ni 49 Ti 51 , Hf was substituted for Ti up to 30 atomic percent. Differential scanning calorimetry was used to determine the transformation temperatures of the as-cast alloys. The peak martensite temperature of the Ni 49 Ti 51 alloy was 69 C and increased to 525 C for the Ni 49 Ti 21 Hf 30 alloy. The peak austenite temperature of the Ni 49 Ti 51 alloy was 114 C and increased to 622 C for the Ni 49 Ti 21 Hf 30 alloy. An apparent minimum in the peak transformation temperatures occurred between 0 and 3 atomic percent Hf. Preliminary experiments were also conducted to determine the effect of thermomechanical processing on the shape memory properties of the Ni 49 Ti 41 Hf 10 . Data are presented on the effect of cold work and heat treatment on the transformation temperatures of this alloy. (orig.)

  16. NUCLEOSYNTHETIC TUNGSTEN ISOTOPE ANOMALIES IN ACID LEACHATES OF THE MURCHISON CHONDRITE: IMPLICATIONS FOR HAFNIUM-TUNGSTEN CHRONOMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Burkhardt, Christoph; Wieler, Rainer [Institute of Geochemistry and Petrology, Clausiusstrasse 25, ETH Zurich, CH-8092 Zurich (Switzerland); Kleine, Thorsten [Institut fuer Planetologie, Westfaelische Wilhelms-Universitaet Muenster, Wilhelm-Klemm-Strasse 10, D-48149 Muenster (Germany); Dauphas, Nicolas, E-mail: burkhardt@erdw.ethz.ch [Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 (United States)

    2012-07-01

    Progressive dissolution of the Murchison carbonaceous chondrite with acids of increasing strengths reveals large internal W isotope variations that reflect a heterogeneous distribution of s- and r-process W isotopes among the components of primitive chondrites. At least two distinct carriers of nucleosynthetic W isotope anomalies must be present, which were produced in different nucleosynthetic environments. The co-variation of {sup 182}W/{sup 184}W and {sup 183}W/{sup 184}W in the leachates follows a linear trend that is consistent with a mixing line between terrestrial W and a presumed s-process-enriched component. The composition of the s-enriched component agrees reasonably well with that predicted by the stellar model of s-process nucleosynthesis. The co-variation of {sup 182}W/{sup 184}W and {sup 183}W/{sup 184}W in the leachates provides a means for correcting the measured {sup 182}W/{sup 184}W and {sup 182}W/{sup 183}W of Ca-Al-rich inclusions (CAI) for nucleosynthetic anomalies using the isotopic variations in {sup 183}W/{sup 184}W. This new correction procedure is different from that used previously, and results in a downward shift of the initial {epsilon}{sup 182}W of CAI to -3.51 {+-} 0.10 (where {epsilon}{sup 182}W is the variation in 0.01% of the {sup 182}W/{sup 183}W ratio relative to Earth's mantle). This revision leads to Hf-W model ages of core formation in iron meteorite parent bodies that are {approx}2 Myr younger than previously calculated. The revised Hf-W model ages are consistent with CAI being the oldest solids formed in the solar system, and indicate that core formation in some planetesimals occurred within {approx}2 Myr of the beginning of the solar system.

  17. ZIRCONIUM—HAFNIUM ISOTOPE EVIDENCE FROM METEORITES FOR THE DECOUPLED SYNTHESIS OF LIGHT AND HEAVY NEUTRON-RICH NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Akram, W.; Schönbächler, M. [School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom); Sprung, P. [Institut für Planetologie, Universität Münster, Wilhelm-Klemm-Strasse 10, D-48149 Münster (Germany); Vogel, N. [Institute for Geochemistry and Petrology, ETH, Clausiusstrasse 25, 8092 Zürich (Switzerland)

    2013-11-10

    Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (≤1ε in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (∼2ε). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ≤ 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ☉}) SNII.

  18. Interaction of zirconium and hafnium tetrachlorides with cesium, rubidium and potassium chlorides and Raman spectra of reaction products

    International Nuclear Information System (INIS)

    Salyulev, A.B.; Vovkotrub, Eh.G.; Strekalovskij, V.N.

    2008-01-01

    Raman spectroscopy was used to reveal the formation of novel complexes involving [Zr 2 Cl 9 ] - and [Hf 2 Cl 9 ] - anions in molten mixtures of ZrCl 4 and HfCl 4 with CsCl, RbCl, and KCl. A prediction is made about the presence of the above-mentioned complex anions in poorly investigated melts of the corresponding binary systems at high concentrations of ZrCl 4 or HfCl 4 [ru

  19. Determination of rare earth elements, hafnium and cadmium in sintered pellets of mixed thorium and uranium oxides by neutron activation

    International Nuclear Information System (INIS)

    Cardoso, S.N.M.

    1987-01-01

    This work shows the development of a method for determination of the rare-earth elements (Eu, Sm, Dy and Gd), Hf and Cd contents in sinterized U and Th mixed oxides by neutron activation analysis. The sample is dissolved in nitric/fluoridric (0,1% HF) medium, to dryness and redissolved in 6N HCl solution. The Hf is extracted into organic phase (0,5 M TTA/benzene), irradiated and analysed through 181 Hf isotope energy peak. The aqueous phase is treated with NH 4 OH for the precipitation of hidroxides. Then, these are dissolved in 6N HNO 3 solution. The extraction of U and Th is made in two steps, one with TBP/CCl 4 and another with 0,5 M TTA/C 6 H 6 . Then the rare-earth elements and Cd are irradiated and determined by gamma spectrometry. (author) [pt

  20. The Polysaccharide Capsule of Campylobacter jejuni 81-176 Modulates the Host Immune Response

    Science.gov (United States)

    2012-12-17

    immune response 3 4 Alexander C. Maue1, Krystle L. Mohawk1, David K. Giles*2, Frédéric Poly1, Cheryl 5 P. Ewing1, Yuening Jiao3, Ginyoung Lee3, Zuchao...McGowan, D. Musher , A. Martin and J. 652 Richards. 1998. Phosphorylcholine on the lipooligosaccharide of 653 Haemophilus influnezae contributes to

  1. 21 CFR 133.176 - Pasteurized cheese spread with fruits, vegetables, or meats.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Pasteurized cheese spread with fruits, vegetables... fruits, vegetables, or meats. (a) Pasteurized cheese spread with fruits, vegetables, or meats, or... prepared cooked, canned, or dried fruit; any properly prepared cooked, canned, or dried vegetable; any...

  2. Godiva IV and Juliet Diagnostics CED-1, Rev. 1 (IER-176)

    Energy Technology Data Exchange (ETDEWEB)

    Scorby, J C; Myers, W L

    2012-04-11

    The Juliet experiment is currently in preliminary design (IER-128). This experiment will utilize a suite of diagnostics to measure the physical state of the device (temperature, surface motion, stress, etc.) and the total and time rate of change of neutron and gamma fluxes. A variety of potential diagnostics has been proposed in this CED-1 report. Based on schedule and funding, a subset of diagnostics will be selected for testing using the Godiva IV pulsed reactor as a source of neutrons and gammas. The diagnostics development and testing will occur over a two year period (FY12-13) culminating in a final set of diagnostics to be fielded for he Juliet experiment currently proposed for execution in FY15.

  3. 176: EVIDENCE-BASED AND EFFECTIVE RESEARCH SKILLS OF IRANIAN MIDDLE SCHOOL STUDENTS

    Science.gov (United States)

    Mostafaei, Helia; Sadeghi-Ghyassi, Fatemeh; Mostafaei, Hadi

    2017-01-01

    Background and aims Recently, digital research is very popular in schools. The capacity of students to do an effective search is unclear which can lead to utilization of unacceptable evidence in their research. Aims To evaluate middle school students' effective search skills. Methods This survey was done during the summer school of Farzanegan talented students middle school. The self-administrated questionnaire studied 30 items about effective search and digital research skills of students. One hundred questionnaires were distributed in this summer school and students in the 7th and 8th grades filled the questionnaires. The administration of the questionnaire was counted as their concept. All data was analyzed at Excel 2013. Results Eighty percent of students including 67.5% of the seventh and 32.5% of the eighth grade students responded to the questionnaires respectively. Shockingly, 96.2% of students only googled and most of them (73.7%) type the topic of their research in Persian to start their research strategy. More than half of them (52.5) believed the result of their search is mostly or always correct and 66.2% of them copy-pasted their findings without any assessment. Surprisingly, only 27.5% of them have proposed that they had problem with appraising the evidence. The best sources of the students for finding the answer of their questions were: Wikipedia, telegram, TV, books, E-Books, YouTube, classmates, Facebook and student information websites, and EBSCO, accordingly. 76.2% acknowledged that internet has turned students into copy machines. Only 31.2% agreed their teachers taught them how to do effective research. Conclusion Most of the students were not familiar with valid sources of research evidence. Language barrier may limit their access to best evidence. Most students were not used to retrieving the evidence.

  4. N-Linked Protein Glycosylation is Required for Full Competence in Campylobacter jejuni 81-176

    National Research Council Canada - National Science Library

    Larsen, Joseph C; Szymanski, Christine; Guerry, Patricia

    2004-01-01

    ...) that have subsequently been found in Helicobacter pylori and Wolinella succinogenes. Mutational analyses of some of these genes have implicated their involvement in intestinal epithelial cell invasion and natural competence...

  5. 76 FR 176 - Amended Certification Regarding Eligibility To Apply for Worker Adjustment Assistance

    Science.gov (United States)

    2011-01-03

    ... Hewlett Packard Company. The workers are engaged in marketing, sales, call center, customer experience... Group--Desktop (Cupertino only), Customer Warranty, Emerging Business, Supply Chain, Volume Operations... Hewlett Packard Company, Personal Systems Group--Desktop (Fort Collins only), Customer Warranty, Emerging...

  6. The accusation of 'world disturbers' (Acts 17:6 in socio-political context

    Directory of Open Access Journals (Sweden)

    Jeremy Punt

    2016-03-01

    Full Text Available �Acts 17:1�9 presents a narrative of the consequences of Paul�s engagements in Thessalonica�s synagogue. Following Paul and Silas� reported successful 3-week mission, some Jews hauled Paul and Silas� host, Jason, and a number of Jesus followers before the authorities. The threefold accusation was that Paul and Silas turned the world upside down, acted against Caesar�s decrees and claimed another king, Jesus. This incident is investigated from the perspective of Acts� presentation of competing missions, in the context of the intersectionality of religion and politics in the 1st century CE. The article challenges a narrow theological interpretation of Acts 17, insisting on the need for and value of a socio-political interpretive lens to make sense of the rhetoric of this chapter.Intradisciplinary and/or interdisciplinary implications: The article challenges a narrow theological interpretation of Acts 17, insisting on the need for and value of a socio-political interpretive lens to make sense of the rhetoric of this chapter.

  7. 18 CFR 367.1760 - Account 176, Derivative instrument assets-Hedges.

    Science.gov (United States)

    2010-04-01

    ... change in the fair value of derivative instrument assets designated by the service company as cash flow... flow hedge it will record the change in the fair value of the derivative instrument in this account... must record the change in the fair value of the derivative instrument in this account with a concurrent...

  8. SEM-analysis of grain boundary porosity in three S-176 specimens

    International Nuclear Information System (INIS)

    Malen, K.; Birath, S.; Mattsson, O.

    1980-10-01

    Porosity in UO 2 -fuel has been studied in scanning electron microscope (SEM). The aim was to obtain a basis for evaluation of porosity in high burnup power reactor fuel. Three specimens have been analyzed. In the high temperature zones porosity can be seen both on grain boundaries and at grain edges. In the low temperature regions very little changes seem to have occurred during irradiation. (author)

  9. 46 CFR 176.600 - Drydock and internal structural examination intervals.

    Science.gov (United States)

    2010-10-01

    ... including fuel tanks, and may require the vessel to be drydocked or taken out of service to assess the extent of the damage, and to effect permanent repairs. The OCMI may also decrease the drydock examination...

  10. 21 CFR 176.210 - Defoaming agents used in the manufacture of paper and paperboard.

    Science.gov (United States)

    2010-04-01

    ... (C9-C15) benzene-sulfonate. Sodium dioctyl sulfosuccinate. Sodium distearyl phosphate. Sodium lauryl sulfate. Sodium lignin sulfonate. Sodium 2-mercaptobenzothiazole. Sodium naphthalenesulfonic acid (3 mols... hydroxide (soaps). Propanol (esters). Propylene glycol (esters). Propylene oxide (esters). Sodium hydroxide...

  11. 21 CFR 176.180 - Components of paper and paperboard in contact with dry food.

    Science.gov (United States)

    2010-04-01

    ... available for inspection at the National Archives and Records Administration (NARA). For information on the.... Monoethyl maleate. 5-Norbornene-2,3-dicarboxylic acid, mono-n-butyl ester. Styrene. Vinyl acetate. Vinyl butyrate. Vinyl chloride. Vinyl crotonate. Vinyl hexoate. Vinylidene chloride. Vinyl pelargonate. Vinyl...

  12. 31 CFR 103.176 - Due diligence programs for correspondent accounts for foreign financial institutions.

    Science.gov (United States)

    2010-07-01

    ... TRANSACTIONS Anti-Money Laundering Programs Special Due Diligence for Correspondent Accounts and Private... an ongoing basis, any known or suspected money laundering activity conducted through or involving any... section shall be a part of the anti-money laundering program otherwise required by this subpart. Such...

  13. : tous les projets | Page 176 | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les États défaillants et fragiles attirent l'attention du monde entier, mais ne représentent que quelques-uns des pays qui ont du mal à instaurer l'ordre et à asseoir leur autorité. Région: South Africa, North and Central America, South America, Brazil, Colombia, Mexico. Programme: Governance and Justice. Financement total ...

  14. 29 CFR 4.176 - Payment of fringe benefits to temporary and part-time employees.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Payment of fringe benefits to temporary and part-time... to temporary and part-time employees. (a) As set forth in § 4.165(a)(2), the Act makes no distinction, with respect to its compensation provisions, between temporary, part-time, and full-time employees...

  15. Benchmarking the State of Chuuk's Education Management Information System. REL 2017-176

    Science.gov (United States)

    Kendall, John S.; Dandapani, Nitara; Cicchinelli, Louis F.

    2016-01-01

    A quality data management system, such as an education management information system (EMIS), a state longitudinal data system, or a data warehouse, is key to ensuring that education policy, planning, and strategy decisions are grounded in accurate information (Data Quality Campaign, 2010; Mohamed, Kadir, May-Lin, Rahman, & Arshad, 2009;…

  16. 29_172 - 176_Bala et al.,_Proximate and Mineral analysis

    African Journals Online (AJOL)

    user pc

    ND MINERAL ELEMENTS COMPOSITION OF FIVE LOCALLY. ONSUMED FRUITS IN KANO STATE, NIGERIA ... ate, Mineral, Atomic Absorption Spectrophotometry, Flame Photometry ltivated in almost all parts gh nutritional value .... bones and teeth, regulation of nerve and muscle function and takes part in milk clotting ...

  17. 49 CFR 176.78 - Use of power-operated industrial trucks on board vessels.

    Science.gov (United States)

    2010-10-01

    ... operation may expose the operator to danger from a falling object, the truck must be equipped with a driver... used to handle small objects or unstable loads must be equipped with a load backrest extension having... must be permanently connected to an exhaust duct leading to the open deck and terminate in a gooseneck...

  18. 46 CFR 176.801 - Notice of inspection deficiencies and requirements.

    Science.gov (United States)

    2010-10-01

    ... equipment is found not to conform to the requirements of law or the regulations in this subchapter, the... passengers or crew, and exists through negligence or willful noncompliance, the marine inspector may issue a...

  19. 49 CFR 176.900 - Packaging and stowage of cotton and vegetable fibers; general.

    Science.gov (United States)

    2010-10-01

    ... loading, the extinguishing system must be examined to ensure that it is in good working condition; and (7... extinguishers may be the vessel's equipment or shore equipment. (h) Smoking is not permitted on a vessel during... designated by the master. “NO SMOKING” signs must be conspicuously posted in appropriate places, and the...

  20. Hyperon production in Ar plus KCl collisions at 1.76A GeV

    Czech Academy of Sciences Publication Activity Database

    Agakishiev, G.; Balanda, A.; Bannier, B.; Belver, D.; Křížek, Filip; Kugler, Andrej; Sobolev, Yuri, G.; Tlustý, Pavel; Wagner, Vladimír

    2011-01-01

    Roč. 47, č. 2 (2011), 21/1-21/8 ISSN 1434-6001 R&D Projects: GA AV ČR IAA100480803; GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : HEAVY-ION COLLISIONS * NUCLEUS-NUCLEUS COLLISIONS * KAON PRODUCTION Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.190, year: 2011

  1. Sexospécificités | Page 176 | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Il y a plus de vingt ans, Charlie Mayer, exploitant d'un ranch dans le sud du Manitoba et également ministre fédéral de l'Agriculture, est rentré au Canada troublé par ce qu'il avait entendu au cours d'une réunion de l'Organisation des Nations Unies pour l'alimentation et l'agriculture (FAO), à Rome. Read more about Cap ...

  2. 176: EVIDENCE-BASED AND EFFECTIVE RESEARCH SKILLS OF IRANIAN MIDDLE SCHOOL STUDENTS

    OpenAIRE

    Mostafaei, Helia; Sadeghi-Ghyassi, Fatemeh; Mostafaei, Hadi

    2017-01-01

    Background and aims Recently, digital research is very popular in schools. The capacity of students to do an effective search is unclear which can lead to utilization of unacceptable evidence in their research. Aims To evaluate middle school students' effective search skills. Methods This survey was done during the summer school of Farzanegan talented students middle school. The self-administrated questionnaire studied 30 items about effective search and digital research skills of students. O...

  3. 49 CFR 176.166 - Transport of Class 1 (explosive) materials on passenger vessels.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Transport of Class 1 (explosive) materials on....166 Transport of Class 1 (explosive) materials on passenger vessels. (a) Only the following Class 1 (explosive) materials may be transported as cargo on passenger vessels: (1) Division 1.4 (explosive...

  4. 49 CFR 176.905 - Motor vehicles or mechanical equipment powered by internal combustion engines.

    Science.gov (United States)

    2010-10-01

    ... of ignition. A motor vehicle or mechanical equipment showing any signs of leakage or electrical fault... equipment is stowed. (f) Each hold or compartment must be ventilated and fitted with an overhead water... smoke or fire detection system capable of alerting personnel on the bridge. (h) All electrical equipment...

  5. New system for production of reactor medical radionuclides tested with Lu-176

    Czech Academy of Sciences Publication Activity Database

    Seifert, Daniel; Kropáček, Martin; Tomeš, Marek; Kučera, Jan; Lebeda, Ondřej

    2015-01-01

    Roč. 42, S (2015), s. 857-857 ISSN 1619-7070. [28th Annual congress of the European-Association-of-Nuclear-Medicine (EANM). 10.10.2015-14.10.2015, Hamburg] R&D Projects: GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : Lu-177 * radionuclides * reactor Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  6. 49 CFR 176.69 - General stowage requirements for hazardous materials.

    Science.gov (United States)

    2010-10-01

    ... equipped with a fixed fire extinguishing and fire detection system, the freight containers or barges need... by paragraph (a) of this section if fire fighting equipment capable of reaching and piercing the..., their removal from a potentially dangerous situation, and the removal of packages in case of fire. (b...

  7. Yeast Interacting Proteins Database: YDR176W, YDL239C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available a Don1p-containing structure at the leading edge of the prospore membrane via interaction with spindle pole...ining structure at the leading edge of the prospore membrane via interaction with spindle pole body componen...DY3 Prey description Protein required for spore wall formation, thought to mediate assembly of a Don1p-conta

  8. Résultats de recherche | Page 176 | CRDI - Centre de recherches ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dans le cadre de ce projet, les chercheurs étudieront l'impact de l'investissement étranger direct (IED) sur l'efficience économique, la pauvreté et les inégalités dans les pays à faible revenu et à revenu intermédiaire. Projet. Les liens entre les changements dans l'utilisation des terres et la santé humaine dans l'est de l' ...

  9. Development of heavy-ion beams at the INS 176-cm SF cyclotron

    International Nuclear Information System (INIS)

    Sato, Kenji; Ohshiro, Yukimitsu; Tanabe, Tetsumi; Sakurada, Yuzo; Yamazaki, Tsutomu.

    1982-10-01

    Heavy-ion beams at the INS SF cyclotron have been developed since the first beam was obtained in 1974. Multiply-charged heavy ions of gaseous material lighter than Ne have been successfully accelerated. An internal ion source for solid material has been made and high-intensity beams of sup(6,7)Li 3 + have been obtained. A pulsed arc power supply of the current-regulator type was constructed by using a tetrode. Two models of the PIG source of the self-heated cold-cathode type have been made and one of them is now in use. Some of the cyclotron components were also improved for efficient use of heavy-ion beams. (author)

  10. Relocation of the Air National Guard 176th Wing to Elmendorf AFB, Alaska

    Science.gov (United States)

    2007-09-01

    Park. Between 20 and 70 moose are estimated by Alaska Fish and Game to live on Elmendorf AFB, depending on the time of year, as portions of the herd ...also supports populations of small mammals including beaver (Castor canadensis), muskrat (Ondatra zibethicus), porcupine (Erethizon dorsatum), red

  11. X-ray tube target

    International Nuclear Information System (INIS)

    Weber, R.G.

    1980-01-01

    A target with an improved heat emissive surface for use in a rotating anode type x-ray tube is described. The target consists of a body having a first surface portion made of x-ray emissive material and a second surface portion made of a heat emissive material comprising at least one of hafnium boride, hafnium oxide, hafnium nitride, hafnium silicide, and hafnium aluminide. (U.K.)

  12. Recovery of metal chlorides from their complexes by molten salt displacement

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1989-01-01

    This patent describes a process for recovering zirconium or hafnium chloride from a complex of zirconium or hafnium tetrachloride and phosphorus oxychloride. The process comprising: introducing liquid complex of zirconium or hafnium tetrachloride and phosphorus oxychloride into an upper portion of a feed column containing zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor. The liquid complex absorbing zirconium or hafnium tetrachloride vapor and producing a bottoms liquid and also producing a phosphorus oxychloride vapor stripped of zirconium or hafnium tetrachloride; introducing the bottoms liquid into a molten salt containing displacement reactor, the reactor containing molten salt comprising at least 30 mole percent lithium chloride and at least 30 mole percent of at least one other alkali metal chloride, the reactor being heated to 30-450 0 C to displace phosphorus oxychloride from the complex and product zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor and zirconium or hafnium tetrachloride-containing molten salt; introducing the zirconium or hafnium tetrachloride vapor and the phosphorus oxychloride vapor into the feed column below the point of introduction of the liquid stream; introducing the zirconium or hafnium tetrachloride containing-molten salt into a recovery vessel where zirconium or hafnium tetrachloride is removed from the molten salt to produce zirconium or hafnium tetrachloride product and zirconium or hafnium chloride-depleted molten salt; and recycling the zirconium or hafnium tetachloride-depleted molten salt to the displacement reactor

  13. Investigation of hyperfine interactions in hafnium compounds with F1-, OH1-, and EDTA ligands by perturbed γ-γ angular correlation

    International Nuclear Information System (INIS)

    Amaral, Antonio A.; Silva, Andreia dos S.; Lapolli, Andre L.; Carbonari, Artur W.; Saxena, Rajendra N.

    2011-01-01

    In this study the hyperfine parameters, including the dynamical nature, Perturbed Angular Correlation (PAC) spectroscopy was used to measure the hyperfine parameters in molecules of ligand compounds in solutions. The measurements were carried out at 295 K and 77 K using 181 Hf → 181 Ta, as probe nuclei. Samples were prepared by adding a small volume of radioactive solution containing the probe nuclei in aqueous solution, buffer solution and ethylenediaminetetraacetic acid (EDTA) used as a ligand with pH between 4 and 5 which correspond to the pH of the saturated EDTA solution and in buffer solution with pH between 9 and 10. The results made possible to understand the impact of each method for PAC measurements. Finally a comparative analysis for the several methods of inserting of the probe nuclei in the sample was made, considering chemical and nuclear aspects. The lack of measurements in this kind of samples justifies the importance of the obtained results. (author)

  14. Origins and evolution of rhyolitic magmas in the central Snake River Plain: insights from coupled high-precision geochronology, oxygen isotope, and hafnium isotope analyses of zircon

    Science.gov (United States)

    Colón, Dylan P.; Bindeman, Ilya N.; Wotzlaw, Jörn-Frederik; Christiansen, Eric H.; Stern, Richard A.

    2018-02-01

    We present new high-precision CA-ID-TIMS and in situ U-Pb ages together with Hf and O isotopic analyses (analyses performed all on the same grains) from four tuffs from the 15-10 Ma Bruneau-Jarbidge center of the Snake River Plain and from three rhyolitic units from the Kimberly borehole in the neighboring 10-6 Ma Twin Falls volcanic center. We find significant intrasample diversity in zircon ages (ranges of up to 3 Myr) and in δ18O (ranges of up to 6‰) and ɛHf (ranges of up to 24 ɛ units) values. Zircon rims are also more homogeneous than the associated cores, and we show that zircon rim growth occurs faster than the resolution of in situ dating techniques. CA-ID-TIMS dating of a subset of zircon grains from the Twin Falls samples reveals complex crystallization histories spanning 104-106 years prior to some eruptions, suggesting that magma genesis was characterized by the cyclic remelting of buried volcanic rocks and intrusions associated with previous magmatic episodes. Age-dependent trends in zircon isotopic compositions show that rhyolite production in the Yellowstone hotspot track is driven by the mixing of mantle-derived melts (normal δ18O and ɛHf) and a combination of Precambrian basement rock (normal δ18O and ɛHf down to - 60) and shallow Mesozoic and Cenozoic age rocks, some of which are hydrothermally altered (to low δ18O values) by earlier stages of Snake River Plain magmatism. These crustal melts hybridize with juvenile basalts and rhyolites to produce the erupted rhyolites. We also observe that the Precambrian basement rock is only an important component in the erupted magmas in the first eruption at each caldera center, suggesting that the accumulation of new intrusions quickly builds an upper crustal intrusive body which is isolated from the Precambrian basement and evolves towards more isotopically juvenile and lower-δ18O compositions over time.

  15. Research Update: A hafnium-based metal-organic framework as a catalyst for regioselective ring-opening of epoxides with a mild hydride source

    International Nuclear Information System (INIS)

    Stephenson, Casey J.; Hassan Beyzavi, M.; Klet, Rachel C.; Hupp, Joseph T.; Farha, Omar K.

    2014-01-01

    Reaction of styrene oxide with sodium cyanoborohydride and a catalytic amount of Hf-NU-1000 yields the anti-Markovnikov product, 2-phenylethanol, with over 98% regioselectivity. On the other hand, propylene oxide is ring opened in a Markovnikov fashion to form 2-propanol with 95% regioselectivity. Both styrene oxide and propylene oxide failed to react with sodium cyanoborohydride without the addition of Hf-NU-1000 indicative of the crucial role of Hf-NU-1000 as a catalyst in this reaction. To the best of our knowledge, this is the first report of the use of a metal-organic framework material as a catalyst for ring-opening of epoxides with hydrides

  16. Bubble point measurement and high pressure distillation column design for the environmentally benign separation of zirconium from hafnium for nuclear power reactor

    International Nuclear Information System (INIS)

    Minh, Le Quang; Kim, Gyeongmin; Lee, Moonyong; Park, Jongki

    2015-01-01

    We examined the feasible separation of ZrCl 4 and HfCl 4 through high pressure distillation as environmentally benign separation for structural material of nuclear power reactor. The bubble point pressures of ZrCl 4 and HfCl 4 mixtures were determined experimentally by using an invariable volume equilibrium cell at high pressure and temperature condition range of 2.3-5..6MPa and 440-490 .deg. C. The experimental bubble point pressure data were correlated with Peng-Robinson equation of state with a good agreement. Based on the vapor-liquid equilibrium properties evaluated from the experimental data, the feasibility of high pressure distillation process for the separation of ZrCl 4 and HfCl 4 was investigated with its main design condition through rigorous simulation using a commercial process simulator, ASPEN Hysys. An enhanced distillation configuration was also proposed to improve energy efficiency in the distillation process. The result showed that a heat-pump assisted distillation with a partial bottom flash could be a promising option for commercial separation of ZrCl 4 and HfCl 4 by taking into account of both energy and environmental advantages

  17. Application of the perturbed angular correlation in the investigation of hyperfine interactions in compounds of hafnium, indium and cadmium with F1-, OH1- and EDTA ligands

    International Nuclear Information System (INIS)

    Amaral, Antonio Acleto

    2011-01-01

    In this study the hyperfine parameters, including the dynamical nature, Perturbed Angular Correlation (PAC) spectroscopy was used to measure the hyperfine parameters in molecules of ligand compounds in solutions. The measurements were carried out at 295 K and 77 K using 111 In → 111 Cd, 181 Hf → 181 Ta and 111m Cd → 111 Cd, as probe nuclei. Samples were prepared by adding a small volume of radioactive solution containing the probe nuclei in aqueous solution, buffer solution and ethylenediaminetetraacetic acid (EDTA) used as a ligand with pH 4.3 which correspond to the pH of the saturated EDTA solution and in buffer solution with pH between 9 and 10. The results made possible to understand the impact of each method for PAC measurements. Finally a comparative analysis for the several methods of inserting of the probe nuclei in the sample was made, considering chemical and nuclear aspects. The lack of measurements in this kind of samples justifies the importance of the obtained results. (author)

  18. Evolution of the mechanical and tribological properties of DLC thin films doped with low-concentration hafnium on 316L steel

    Science.gov (United States)

    Qi, Meng; Xiao, Jianrong; Gong, Chenyang; Jiang, Aihua; Chen, Yong

    2018-01-01

    Low concentrations (stainless steel and silicon (1 0 0) substrates by magnetron sputtering to attain superior mechanical and tribological properties. Ar and CH4 were used as source gases. The microstructure, chemical composition, and morphology of the Hf-DLC thin films in various concentrations were analyzed using x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. Results showed that Hf species transferred from the particulate microstructure to Hf carbide phases, and the surface roughness increased monotonically with increasing Hf concentration. Moreover, the hardness and elastic modulus exhibited high values when the doped Hf concentration was 0.42 at%. Similarly, the tribological behaviors and wear life of Hf-DLC thin films had a low friction coefficient and excellent wear resistance at 0.42 at% Hf concentration. Therefore, 0.42 at% Hf is an optimal doping concentration to improve the mechanical and tribological properties of DLC thin films. Generally, the use of low-concentration Hf doping into DLC thin films is novel, and the present results provide guidance for the selection of suitable and effective concentration to optimize Hf-DLC thin films with superior performance.

  19. TiNi shape memory alloys: effects of the fabrication route, the oxygen content and the zirconium or hafnium additions on the metallurgical characteristics and the thermomechanical properties

    International Nuclear Information System (INIS)

    Olier, P.

    1996-01-01

    In order to promote the development of Ti-Ni shape memory alloys, we have studied the correlation between the fabrication route, the chemical composition (O 2 content, Zr or Hf additions), the metallurgical characteristics and the thermomechanical properties. A conventional sintering does not allow to obtain a homogeneous compound of pure Ti 50 Ni 50 alloy because of the occurrence of Kirkendall porosities which act as a diffusion barrier. An original process including combustion synthesis and hot-extrusion was successfully developed. Resulting products exhibit a smaller grain size (15-20μm) and an enhanced workability in comparison with products obtained by arc-melting and subsequent hot rolling. The presence of oxygen in equiatomic Ti-Ni alloy induces the oxide precipitation of Ti 4 Ni 2 O x type (with x ≤ 1). The precipitated particle fraction is proportional to the oxygen nominal content of the alloy. We show that the decrease of the transformation temperatures is correlated with the decrease of Ti in solid solution due to Ti 4 Ni 2 O precipitation. Moreover, we find that a fine and homogenous oxide dispersion is suitable to decrease the grain size during hot rolling and to enhance to the one way shape memory properties. An increase of the typical transformation temperatures is obtained through of Zr or Hf (in substitution to Ti). But, an increase of the hardness is measured, and consequently the workability of the ternary alloys becomes reduced. However, it is worthwhile to point out that a Ti 38 Ni 50 Hf 12 product obtained by arc melting and hot extrusion is able to fully recover an apparent plastic strain of more than 4% during tensile tests performed under special loading conditions. Such as behaviour is of great interest with respect to potential applications in a temperature range higher that 100 deg. C. (author)

  20. Tunable white light emission from hafnium oxide films co-doped with trivalent terbium and europium ions deposited by Pyrosol technique

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Olguin, J.C.; Montes, E.; Guzman-Mendoza, J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada del Instituto Politecnico Nacional, Unidad Legaria (Mexico); Baez-Rodriguez, A.; Zamora-Peredo, L. [Centro de Investigacion en Micro y Nanotecnologia, Universidad Veracruzana, Boca del Rio, Ver (Mexico); Garcia-Hipolito, M.; Alvarez-Fregoso, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Coyoacan (Mexico); Martinez-Merlin, I.; Falcony, C. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional (Mexico)

    2017-10-15

    In this paper, the photo and cathodoluminescent properties of HfO{sub 2} films optically activated with different atomic concentrations of Tb{sup 3+} and Eu{sup 3+} ions, deposited by the Pyrosol technique, are reported. These films were deposited at temperatures from 400 to 600 C, using chlorides as raw materials. The surface morphologies of all deposited films were rough and dense. X-ray diffraction analysis showed that the films deposited at 600 C were polycrystalline exhibiting the HfO{sub 2} monoclinic phase. The tuning by the means of the excitation wavelength generates photoluminescence spectra, for co-doped films, in several emissions from blue to yellow (including white light) due to the characteristic electronic transitions of Tb{sup 3+} (green), Eu{sup 3+}(red) ions and the violet-blue emission associated to the host lattice (HfO{sub 2}). According to the chromaticity diagram, the best white light is reached for the sample S2 excited with 382 nm (x = 0.3343, y = 0.3406). The cathodoluminescence emission spectra for co-doped films showed emissions from green to red (including yellow, orange and other intermediate emissions). The averaged quantum efficiency values of the sample labeled as S2 resulted between 47 and 78% depending on the excitation wavelength. In addition, XPS, TEM, SEM and decay times were performed to characterize these films. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)