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Sample records for bare high purity

  1. Performance of bare high-purity germanium detectors in liquid argon for the GERDA experiment

    CERN Document Server

    Heider, Marik Barnabé; Chkvorets, Oleg; Di Vacri, Assunta; Gusev, Konstantin; Schönert, Stefan; Shirchenko, Mark

    2008-01-01

    The GERmanium Detector Array, GERDA, will search for neutrinoless double beta decay in 76Ge at the National Gran Sasso Laboratory of the INFN. Bare high-purity germanium detectors enriched in 76Ge will be submerged in liquid argon serving simultaneously as a shield against external radioactivity and as a cooling medium. In GERDA Phase-I, reprocessed enriched-Ge detectors, which were previously operated by the Heidelberg-Moscow and IGEX collaborations, will be redeployed. Before operating the enriched detectors, tests are performed with non-enriched bare HPGe detectors in the GERDA underground Detector Laboratory to test the Phase-I detector assembly, the detector handling protocols, the refurbishment technology and to study the long-term stability in liquid argon. The leakage currents in liquid argon and liquid nitrogen have been extensively studied under varying gamma irradiation conditions. In total three non-enriched high-purity p-type prototype germanium detectors have been operated successfully. The dete...

  2. Performance and stability tests of bare high purity germanium detectors in liquid argon for the GERDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barnabe Heider, Marik

    2009-05-27

    GERDA will search for neutrinoless double beta decay of {sup 76}Ge by using a novel approach of bare germanium detectors in liquid argon (LAr). Enriched germanium detectors from the previous Heidelberg-Moscow and IGEX experiments have been reprocessed and will be deployed in GERDA Phase-I. At the center of this thesis project is the study of the performance of bare germanium detectors in cryogenic liquids. Identical detector performance as in vacuum cryostats (2.2 keV FWHM at 1.3 MeV) was achieved in cryogenic liquids with a new low-mass detector assembly and contacts. One major result is the discovery of a radiation induced leakage current (LC) increase when operating bare detectors with standard passivation layers in LAr. Charge collection and build-up on the passivation layer were identified as the origin of the LC increase. It was found that diodes without passivation do not exhibit this feature. Three month-long stable operation in LAr at {proportional_to} 5 pA LC under periodic gamma irradiation demonstrated the suitability of the modi ed detector design. Based on these results, all Phase-I detectors were reprocessed without passivation layer and subsequently successfully characterized in LAr in the GERDA underground Detector Laboratory. The mass loss during the reprocessing was {proportional_to}300 g out of 17.9 kg and the exposure above ground {proportional_to} 5 days. This results in a negligible cosmogenic background increase of {proportional_to} 5.10{sup -4} cts/(keV.kg.y) at {sup 76}Ge Q{sub {beta}}{sub {beta}} for {sup 60}Co and {sup 68}Ge. (orig.)

  3. Performance and stability tests of bare high purity germanium detectors in liquid argon for the GERDA experiment

    International Nuclear Information System (INIS)

    GERDA will search for neutrinoless double beta decay of 76Ge by using a novel approach of bare germanium detectors in liquid argon (LAr). Enriched germanium detectors from the previous Heidelberg-Moscow and IGEX experiments have been reprocessed and will be deployed in GERDA Phase-I. At the center of this thesis project is the study of the performance of bare germanium detectors in cryogenic liquids. Identical detector performance as in vacuum cryostats (2.2 keV FWHM at 1.3 MeV) was achieved in cryogenic liquids with a new low-mass detector assembly and contacts. One major result is the discovery of a radiation induced leakage current (LC) increase when operating bare detectors with standard passivation layers in LAr. Charge collection and build-up on the passivation layer were identified as the origin of the LC increase. It was found that diodes without passivation do not exhibit this feature. Three month-long stable operation in LAr at ∝ 5 pA LC under periodic gamma irradiation demonstrated the suitability of the modi ed detector design. Based on these results, all Phase-I detectors were reprocessed without passivation layer and subsequently successfully characterized in LAr in the GERDA underground Detector Laboratory. The mass loss during the reprocessing was ∝300 g out of 17.9 kg and the exposure above ground ∝ 5 days. This results in a negligible cosmogenic background increase of ∝ 5.10-4 cts/(keV.kg.y) at 76Ge Qβ for 60Co and 68Ge. (orig.)

  4. Synthesis of high purity hexanitrostilbene

    Energy Technology Data Exchange (ETDEWEB)

    Stull, T.W.

    1975-09-01

    The development of a continuous process and the apparatus for the synthesis of high purity hexanitrostilbene type I (HNS I) are described. Optimum solution concentrations and ratios were investigated, and product washing and slurrying procedures were developed to yield a high purity product. The synthesized products were evaluated against the Navy's WS-5003F specification. In addition, other tests suggested by Sandia Laboratory and/or developed in-house, were employed to enable better classification of the explosive and to assure its suitability for ultimate use. Information in this document will enable any facility to synthesize HNS I at a purity level of approximately 99.5 percent, with yields approaching 38 percent.

  5. High purity limestone quest

    OpenAIRE

    Mitchell, Clive

    2011-01-01

    Limestone probably has the largest number of commercial applications of all the industrial minerals. These include construction (aggregate, rail ballast and dimension stone), mineral fillers (in paper, paint, plastic, rubber and pharmaceuticals), adhesives, abrasives, fertilisers, food additives, environmental applications (acidity neutralisation, flue gas desulphurisation, soil conditioning and stabilisation), and production of cement, lime and calcium chemicals. ‘High-purity’ limestone i...

  6. High purity products by crystallisation

    NARCIS (Netherlands)

    Verdoes, D.; Bassett, J.M.

    2009-01-01

    Crystallisation from a melt or solution has the potential to yield a product with a very high purity in a single equilibrium step. Pure crystals have to be separated from the impure mother liquor, which is usually done by standard solid-liquid separation techniques like filtration or centrifugation.

  7. High purity tellurium dioxide production

    International Nuclear Information System (INIS)

    The method of high purity tellurium dioxide production has been developed which deals with the powdered tellurium dissolvent in the hydrochloric acid in the presence of hydrogen peroxide followed by ammonia deposition, pH being 0.5-2.0. Tellurium dioxide output is 21.6-95.6 % relatively to the theoretical one. The content of separate due impruties doesn-t eceed 10-4 -10-6% mas. 14 refs., 2 figs., 3 tabs

  8. High purity conductivity cell standardization

    International Nuclear Information System (INIS)

    High purity conductivity is the first line of defense in detecting contamination entering the steam cycle. Long-term accuracy of this measurement is essential in maintaining operation within established water quality guidelines. More accurate temperature measurement and specialized temperature compensation for the properties of high purity water with various trace treatment materials, along with high performance measuring circuit design have greatly improved measurement capabilities. However, the integrity of the conductivity cell itself, especially over the long term, still comes into question. The conductivity cell is now probably the greatest source of uncertainty in the measurement. The traditional certified glass and platinum cell may not retain its precise constant after rough handling or even shipping. Newer cell designs with concentric titanium electrodes are now being certified and provide much better durability of their cell constant. Many plants have standardized on these as the basis for checking other cells. The plant standard cell is kept clean, is carefully handled, and may be returned to the manufacturer periodically for re-certification to maintain its integrity. However, some plants require that cells be verified in-house periodically using standard solutions

  9. Thermal conductivity of high purity vanadium

    International Nuclear Information System (INIS)

    The thermal conductivity, Seebeck coefficient, and electrical resistivity of four high purity vanadium samples have been measured as functions of temperature over the temperature range 5 to 3000K. The highest purity sample had a resistance ratio (rho/sub 2730K//rho /sub 4.20K/) of 1524. The highest purity sample had a thermal conductivity maximum of 920 W/mK at 90K and had a thermal conductivity of 35 W/mK at room temperature. At low temperatures the thermal resistivity was limited by the scattering of electrons by impurities and phonons. The thermal resistivity of vanadium departed from Matthiessen's rule at low temperatures. The electrical resistivity and Seebeck coefficient of high purity vanadium showed no anomalous behavior above 1300K. The intrinsic electrical resistivity at low temperatures was due primarily to interband scattering of electrons. The Seebeck coefficient was positive from 10 to 2400K and had a maximum which was dependent upon sample purity. (auth)

  10. High-purity germanium crystal growing

    International Nuclear Information System (INIS)

    The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 1010cm-3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers

  11. High-purity enrichment of 84Sr

    International Nuclear Information System (INIS)

    High-purity 84Sr (i.e., >99 at %) is an important tool in many areas of basic and applied research, in particular for spikes used in isotopic dilution/mass spectrometer investigations in geochemistry, cosmochemistry, and paleoclimate-age studies. In nature, the 84Sr abundance is only 0.56%; however, it can be enriched to the specified requirements by using a high-resolution separator, such as the 180 deg. -sector separator, or by completing two passes through a high-production, lower-resolution machine, such as the calutron. The latter option was used for this enrichment to produce ∼1 g of strontium with a final 84Sr concentration of 99.64%. Three innage runs were made, vaporizing a total of ∼17 g of metal feed that had been pre-enriched in the calutron to ∼70% 84Sr. A partial recovery, followed by recycle of the unresolved feed, was made after the second innage run. A process efficiency of 8.44% was achieved, and 4.33 g of the unresolved feed material was recovered. A modified ion-source unit using materials compatible with strontium and the use of krypton as mass markers to aid in operations are described. Standard contamination analyses were performed to evaluate the enrichment and to compare measured results with predicted product purity

  12. Highly Accurate Sensor for High-Purity Oxygen Determination Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this STTR effort, Los Gatos Research (LGR) and the University of Wisconsin (UW) propose to develop a highly-accurate sensor for high-purity oxygen determination....

  13. Multielement trace determination in high purity advanced ceramics and high purity metals

    Indian Academy of Sciences (India)

    R Matschat; H-J Heinrich; M Czerwensky; S Kuxenko; H Kipphardt

    2005-07-01

    In the field of advanced ceramics two CRMs were developed in the last few years by the Federal Institute for Materials Research and Testing, one for silicon nitride and one for silicon carbide. Besides their application by industry they are appropriate to be used for the validation of special methods used for trace determination in accordance with high purity materials. This is demonstrated, for example, on ultrapure silicon carbide which was analysed by solid sampling electrothermal atomic absorption spectrometry (SS ET AAS). BAM is also certifying primary pure reference materials used as the National Standards for inorganic analysis in Germany. The crucial point of this project is the certification of the total purity of high purity materials, each representing one element of the periodic table. A variety of different analytical methods was necessary to determine the trace contents of metallic and non-metallic impurities from almost the whole periodic table in the high purity materials. The primary CRMs of copper, iron and molybdenum are used as examples to demonstrate the modus operandi, analytical effects observed by using high resolution ICP mass spectrometry (HR ICP–MS) and the results.

  14. Workshop on Preserving High Purity Uranium-233

    Energy Technology Data Exchange (ETDEWEB)

    Krichinsky, Alan M [ORNL; Giaquinto, Joseph [ORNL; Canaan, R Douglas {Doug} [ORNL

    2016-01-01

    A workshop was held on at the MARC X conference to provide a forum for the scientific community to communicate needs for high-purity 233U and its by-products in order to preserve critical items otherwise slated for downblending and disposal. Currently, only a small portion of the U.S. holdings of separated 233U is being preserved. However, many additional kilograms of 233U (>97% pure) still are destined to be downblended which will permanently destroy their potential value for many other applications. It is not likely that this material will ever be replaced due to a lack of operating production capability. Summaries of information conveyed at the workshop and feedback obtained from the scientific community are presented herein.

  15. Production of high purity uranium compounds from crude yellow cake

    International Nuclear Information System (INIS)

    High purity ammonium uranyl tricarbonate is produced from crude plant yellow cake by treatment of the yellow cake with a mineral acid, neutralization of the acidic solution with a conversion of the uranium therein to ammonium uranyl tricarbonate, precipitation of the ammonium uranyl tricarbonate with a nonsolvent, followed by separation. Optionally, the ammonium uranyl tricarbonate can be calcined to produce high purity uranium oxides

  16. Delta Doping High Purity CCDs and CMOS for LSST

    Science.gov (United States)

    Blacksberg, Jordana; Nikzad, Shouleh; Hoenk, Michael; Elliott, S. Tom; Bebek, Chris; Holland, Steve; Kolbe, Bill

    2006-01-01

    A viewgraph presentation describing delta doping high purity CCD's and CMOS for LSST is shown. The topics include: 1) Overview of JPL s versatile back-surface process for CCDs and CMOS; 2) Application to SNAP and ORION missions; 3) Delta doping as a back-surface electrode for fully depleted LBNL CCDs; 4) Delta doping high purity CCDs for SNAP and ORION; 5) JPL CMP thinning process development; and 6) Antireflection coating process development.

  17. High purity efficient first Stokes Raman laser

    Science.gov (United States)

    Liu, Xiaomeng; Liu, Qinyong; Li, Daijun; Du, Keming

    2015-02-01

    The subject of the solid-state Raman frequency conversion to the yellow frequency spectra has been an active topic since the mid 1990's, because of its application in bio-medical and astronomy fields. However, the yellow laser performance is often limited because of the cascade conversion to second or higher Stokes. This cascade conversion not only limits the conversion efficiency and the output power of the first Stokes, but also degrades the pulse and the beam profile of the first Stokes. We present a type of polarization coupled Raman resonator, in which the higher order ( the second Stokes and higher ) laser output can be dramatically suppressed. Our Raman resonator is pumped by a Q-switched and frequency doubled slab laser, and we can get an almost pure (P559/(P559 +P532)>99%) 559 nm yellow light output with an efficiency over 39% from 532 nm to 559 nm. The resonator includes a high reflection rear mirror, a KGW crystal, a polarization coupled input/output element, and a high reflection output coupler of 559 nm (R559 nm = 0.6). Furthermore, we have proposed an improvement of this polarization coupled Raman resonator. The theoretical calculations of the temporal and spatial dependent Raman conversion equations show that the conversion efficiency of the first order Stokes is greatly enhanced with an additionalλ/2 waveplate for 589 nm and the BBO crystal.

  18. High purity tellurium production using dry refining processes

    Indian Academy of Sciences (India)

    N R Munirathnam; D S Prasad; J V Rao; T L Prakash

    2005-07-01

    Tellurium (99.95 at.% purity) is purified using dry processes such as selective vapourization and zone melting in a thoroughly etched and cleaned quartz boat, under continuous flow of hydrogen (H2) gas. The tellurium ingot was quadruple zone refined (QZR) under continuous flow of H2 gas. Thus, the purified tellurium of ultra high purity (UHP) grade is analysed for 60 impurity elements in the periodic table using glow discharge mass spectrometer (GDMS). The sum of all elemental impurities indicate that the purity of tellurium as 7N (99.99999 at.%). The total content of gas and gas forming impurities like O, N and C are found to be within acceptable limits for opto-electronic applications.

  19. Cryoforming evaluation using high-purity nickel

    Energy Technology Data Exchange (ETDEWEB)

    Lord, D. E.; Meisner, L. F.

    1976-09-14

    The cryogenic forming process was evaluated using nickel 270 to see if it had significant advantages over room-temperature (RT) forming. Typically, the procedure involved fast-strain-rate forming a set of nickel samples at cryogenic temperatures and another set at RT. Both sets were measured at RT for failure strength and their strength-preparation elongation curves compared at equal strains. Two more sets were formed, this time at slow strain rates (one at cryogenic temperatures, the other at RT). Both sets were measured at RT for failure strength and their strength-preparation elongation curves of these sets compared with the previous two at equal temperatures and strains. Cryoforming produced a 30 percent higher-strength nickel than that produced at room temperature at equal strains and strain rates. Forming rate effects disappeared as working temperature decreased. Rate-insensitive cryoforming produced a considerably stronger room-temperature material than room-temperature forming at high strain rates. Transmission electron microscopy indicated apparent structural differences between cryoformed and room-temperature-formed nickel. 14 fig. (DLC)

  20. Thermocurrent dosimetry with high purity aluminum oxide

    Energy Technology Data Exchange (ETDEWEB)

    Fullerton, G.D.; Cameron, J.R.; Moran, P.R.

    1976-01-01

    The application of thermocurrent (TC) to ionizing radiation dosimetry was studied. It was shown that TC in alumina (Al/sub 2/O/sub 3/) has properties that are suited to personnel dosimetry and environmental monitoring. TC dosimeters were made from thin disks of alumina. Aluminum electrodes were evaporated on each side: on one face a high voltage electrode and on the opposite face a measuring electrode encircled by a guard ring. Exposure to ionizing radiation resulted in stored electrons and holes in metastable trapping sites. The signal was read-out by heating the dosimeter with a voltage source and picnometer connected in series between the opposite electrodes. The thermally remobilized charge caused a transient TC. The thermogram, TC versus time or temperature, is similar to a TL glow curve. Either the peak current or the integrated current is a measure of absorbed dose. Six grades of alumina were studied from a total of four commercial suppliers. All six materials displayed radiation induced TC signals. Sapphire of uv-grade quality from the Adolf Meller Co. (AM) had the best dosimetry properties of those investigated. Sources of interference were studied. Thermal fading, residual signal and radiation damage do not limit TC dosimetry. Ultraviolet light can induce a TC response but it is readily excluded with uv-opaque cladding. Improper surface preparation prior to electrode evaporation was shown to cause interference. A spurious TC signal resulted from polarization of surface contaminants. Spurious TC was reduced by improved cleaning prior to electrode application. Polished surfaces resulted in blocking electrodes and caused a sensitivity shift due to radiation induced thermally activated polarization. This was not observed with rough cut surfaces.

  1. Low cost routes to high purity silicon and derivatives thereof

    Science.gov (United States)

    Laine, Richard M; Krug, David James; Marchal, Julien Claudius; Mccolm, Andrew Stewart

    2013-07-02

    The present invention is directed to a method for providing an agricultural waste product having amorphous silica, carbon, and impurities; extracting from the agricultural waste product an amount of the impurities; changing the ratio of carbon to silica; and reducing the silica to a high purity silicon (e.g., to photovoltaic silicon).

  2. Electrochemical study of aluminum corrosion in boiling high purity water

    Science.gov (United States)

    Draley, J. E.; Legault, R. A.

    1969-01-01

    Electrochemical study of aluminum corrosion in boiling high-purity water includes an equation relating current and electrochemical potential derived on the basis of a physical model of the corrosion process. The work involved an examination of the cathodic polarization behavior of 1100 aluminum during aqueous oxidation.

  3. High-purity limestone assessment : from mine to market

    OpenAIRE

    Mitchell, Clive

    2009-01-01

    High-purity limestone can be defined as carbonate rock that contains greater than 97% calcium carbonate (CaCO3, typically as calcite); it is often referred to as high-calcium or highly-calcitic limestone. Limestone has by far the largest number of commercial uses of all the industrial minerals; including construction (aggregate, cement and dimension stone), mineral fillers (for paper, paint, plastic, rubber and pharmaceuticals), adhesives, abrasives, fertilisers and soil conditioners, the pro...

  4. Recrystallization behavior of high purity aluminum at 300 ℃

    Institute of Scientific and Technical Information of China (English)

    DU Yu-xuan; ZHANG Xin-ming; YE Ling-ying; LUO Zhi-hui

    2006-01-01

    The recrystallization behavior of 98.5% cold rolled high purity aluminum foils annealed at 300 ℃ was investigated, and the evolution of the microstructures was followed by electron back scattered diffraction(EBSD). The results show that the recrystallization process of the high purity aluminum foils at 300 ℃ is a mixture of discontinuous- and continuous-recrystallization.The orientations of the recrystallization nuclei include not only the cube orientation, but also other orientations such as some near deformation texture components which are the results of strong recovery process. However, such continuously recrystallized grains are usually associated with relatively high free energy, so they would be consumed by the discontinuously-recrystallized grains (cube-oriented grains) in subsequent annealing. On the other hand, the pattern quality index of recrystallized grains shows dependence on the crystal orientation which might introduce some errors into evaluating volume fraction of recrystallization by integrating pattern quality index of EBSD.

  5. High purity zirconium obtainment through the iodine compounds transport method

    International Nuclear Information System (INIS)

    This paper describes the experimental method and the equipment designed, constructed and actually applied for the high purity zirconium obtainment from a zirconium sponge of the nuclear type. The mechanism of purification is based on the impure metal attack with gaseous iodine (at 200 deg C) to obtain zirconium tetra iodine as main product which is then transformed into a pure zirconium base (at 1000-1300 deg C), precipitating the metallic zirconium and releasing the gaseous iodine. From the first experiences carried out, pure zirconium has been obtained from an initial filament of 0.5 mm of diameter as well as wires up to 2.5 mm of diameter. This work presents the results from the studies and analysis made to characterize the material obtained. Finally, the refining methods to which the zirconium produced may be submitted so as to optimize the final purity are discussed. (Author)

  6. Spectroscopic Determination of Trace Contaminants in High Purity Oxygen

    Science.gov (United States)

    Hornung, Steven D.

    2011-01-01

    Oxygen used for extravehicular activities (EVA) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. Measurement of oxygen purity above 99.5% is problematic, and currently only complex instruments such as gas chromatographs or mass spectrometers are used for these determinations. Because liquid oxygen boil-off from the space shuttle will no longer be available to supply oxygen for EVA use, other concepts are being developed to produce and validate high purity oxygen from cabin air aboard the International Space Station. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen was developed at White Sands Test Facility. This instrument uses a glow discharge in reduced pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants and may lend itself to a device capable of on-orbit verification of oxygen purity. System design and optimized measurement parameters are presented.

  7. Neutron energy determination with a high-purity germanium detector

    Science.gov (United States)

    Beck, Gene A.

    1992-01-01

    Two areas that are related to planetary gamma-ray spectrometry are investigated. The first task was the investigation of gamma rays produced by high-energy charged particles and their secondaries in planetary surfaces by means of thick target bombardments. The second task was the investigation of the effects of high-energy neutrons on gamma-ray spectral features obtained with high-purity Ge-detectors. For both tasks, as a function of the funding level, the experimental work was predominantly tied to that of other researchers, whenever there was an opportunity to participate in bombardment experiments at large or small accelerators for charged particles.

  8. Weldability of a high purity offshore cast steel

    Energy Technology Data Exchange (ETDEWEB)

    Koivula, J.; Katila, R.; Liimatainen, J.; Martikainen, H.

    1989-01-01

    High purity, high strength cast steels with excellent weldability have been developed for offshore components with wall thicknesses up to 200 mm. The three new steel grades developed were given the designations OS 340, OS 540, and OS 690 according to their respective guaranteed yield strengths. The strengthening of OS steels is based mainly on solid solution hardening. Microalloying is not used because of weldability requirements. As a result of the ultra-low impurity content and low carbon contents the grain boundaries are clean of carbides, segregated impurities, and non-metallic inclusions, which contribute to the excellent toughness of these steels. (author).

  9. Competitive growth of high purity aluminum grains in directional solidification

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jiao; SHU Da; WANG De-lin; SUN Bao-de; CHEN Gang

    2006-01-01

    A self-made directional solidification setup was used to prepare high purity aluminum ingots of 100mm in diameter. The morphology of the growth interface was detected by SEM and AFM, and the grain lattice orientation was detected by XRD. The results indicate that the grains suffer competitive growth under any conditions in experiments. The lattice orientation of the preferred grains is determined by the flow field above the solid-liquid interface. The horizontal lattice position does not change during the growth process. However, the lattice orientation in the growth direction varies with the growth velocity and approaches to [100]gradually during the growth process.

  10. Textures in high purity aluminum foils and AA3004 sheets

    Institute of Scientific and Technical Information of China (English)

    肖亚庆; 张新明; 唐建国; 邓运来; 陈志永

    2003-01-01

    The simulation of rolling texture with "minimum shear principle" and the strengthening of cube recrystallization texture by inhomogeneous rolling, low strain deformation and multistage annealing, of the formation and evolution of texture in high purity Al were presented. The plastic anisotropy of crystalline materials were also summarized, including determination of the co-yield surfaces and condition of slipping as well as mechanical twinning, prediction of plastic anisotropy of deep drawing with modified Tuckers method, evolution of earing behavior of Al alloy sheets for deep drawing with CMTP approach, and construction of texture balance design and some technologies to suppress plastic anisotropy in practical production.

  11. The compressibility of high purity YbB2.

    Science.gov (United States)

    Kalkan, B; Suzer, S; Ozdas, E

    2012-08-29

    The compressibility and phase stability of Y bB(2) are investigated under high pressure using high-resolution synchrotron x-ray diffraction in a diamond anvil cell. The bulk modules of high purity Y bB(2) is obtained as ∼182 GPa using the Birch-Murnaghan equation of state. The patterns measured up to 20 GPa and the pressure dependence of normalized lattice parameters, a/a(0) and c/c(0), reveal that the compressibility of Y bB(2) is low and fairly isotropic, and this material can be classified as a hard material. X-ray photoemission studies demonstrate that Yb in Y bB(2) has a mostly trivalent valence state at room temperature. Moreover, sample preparation details provide a new insight into the high purity synthesis of Y bB(2) at ambient pressure and moderate temperatures. The presented structural and compressibility results are in agreement with the available theoretical and experimental data on binary rare-earth borides and can serve as a reliable reference for future studies. PMID:22850355

  12. High purity neodymium acetate from mixed rare earth carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos A. da Silva; Rocha, Soraya M. Rizzo da; Vasconcellos, Mari E. de; Lobo, Raquel M.; Seneda, Jose A., E-mail: cqueiroz@ipen.b, E-mail: smrrocha@ipen.b, E-mail: mstela@ipen.b, E-mail: rmlobo@ipen.b, E-mail: jaseneda@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pedreira, Walter dos R., E-mail: walter.pedreira@fundacentro.gov.b [Fundacao Jorge Duprat Figueiredo de Seguranca e Medicina do Trabalho (FUNDACENTRO), Sao Paulo, SP (Brazil)

    2011-07-01

    A simple and economical chemical process for obtaining high purity neodymium acetate is discussed. The raw material in the form rare earth carbonate is produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography technique with a strong cationic resin, proper to water treatment, and without the use of retention ions was used for the fractionating of the rare earth elements (REE). In this way, it was possible to obtain 99.9% pure Nd{sub 2}O{sub 3} in yields greater than or equal 80%, with the elution of the REE using ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in pH controlled. The complex of EDTA-neodymium was transformed into neodymium oxide, which was subsequently dissolved in acetic acid to obtain the neodymium acetates. Molecular absorption spectrophotometry was used to monitor the neodymium content during the process and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the neodymium acetates. The typical neodymium acetates obtained contain the followings contaminants in {mu}g g{sup -1}: Sc(5.1); Y (0.9); La (1.0); Ce (6.1); Pr (34,4); Sm (12.8); Eu (1.1); Gd (15.4); Tb (29.3); Dy (5.2), Ho(7.4); Er (14.6); Tm (0.3); Yb (2.5); Lu (1.0). The high purity neodymium acetates obtained from this procedure have been applied, replacing the imported product, in research and development area on rare earth catalysts. (author)

  13. Recent developments in high purity niobium metal production at CBMM

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, Gustavo Giovanni Ribeiro, E-mail: Gustavo.abdo@cbmm.com.br; Sousa, Clovis Antonio de Faria, E-mail: Clovis@cbmm.com.br; Guimarães, Rogério Contato, E-mail: Rogerio.guimaraes@cbmm.com.br; Ribas, Rogério Marques, E-mail: Rogerio.ribas@cbmm.com.br; Vieira, Alaércio Salvador Martins, E-mail: Alaercio.vieira@cbmm.com.b; Menezes, Andréia Duarte, E-mail: Amenezes@cbmm.com.br; Fridman, Daniel Pallos, E-mail: Daniel.fridman@cbmm.com.br; Cruz, Edmundo Burgos, E-mail: Edmundo@cbmm.com.br [CBMM – Companhia Brasileira de Metalurgia e Mineração Córrego da Mata, s/n Araxá, Minas Gerais 38183-903 Brazil (Brazil)

    2015-12-04

    CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM’s position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM’s ingots is for the manufacture of particle accelerators (superconducting radio frequency – SRF – cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world’s largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient.

  14. Recent developments in high purity niobium metal production at CBMM

    Science.gov (United States)

    Abdo, Gustavo Giovanni Ribeiro; Sousa, Clovis Antonio de Faria; Guimarães, Rogério Contato; Ribas, Rogério Marques; Vieira, Alaércio Salvador Martins; Menezes, Andréia Duarte; Fridman, Daniel Pallos; Cruz, Edmundo Burgos

    2015-12-01

    CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM's position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM's ingots is for the manufacture of particle accelerators (superconducting radio frequency - SRF - cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world's largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient.

  15. Recent developments in high purity niobium metal production at CBMM

    International Nuclear Information System (INIS)

    CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM’s position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM’s ingots is for the manufacture of particle accelerators (superconducting radio frequency – SRF – cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world’s largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient

  16. A TNFR2-Agonist Facilitates High Purity Expansion of Human Low Purity Treg Cells

    OpenAIRE

    Xuehui He; Sija Landman; Stijn C G Bauland; Juliette van den Dolder; Koenen, Hans J.P.M.; Irma Joosten

    2016-01-01

    Regulatory T cells (Treg) are important for immune homeostasis and are considered of great interest for immunotherapy. The paucity of Treg numbers requires the need for ex vivo expansion. Although therapeutic Treg flow-sorting is feasible, most centers aiming at Treg-based therapy focus on magnetic bead isolation of CD4+CD25+ Treg using a good manufacturing practice compliant closed system that achieves lower levels of cell purity. Polyclonal Treg expansion protocols commonly use anti-CD3 plu...

  17. MACRIB High efficiency - high purity hadron identification for DELPHI

    CERN Document Server

    Albrecht, Z; Moch, M; Albrecht, Zoltan; Feindt, Michael; Moch, Markus

    2001-01-01

    Analysis of the data shows that hadron tags of the two standard DELPHI particle identification packages RIBMEAN and HADSIGN are weakly correlated. This led to the idea of constructing a neural network for both kaon and proton identification using as input the existing tags from RIBMEAN and HADSIGN, as well as preproccessed TPC and RICH detector measurements together with additional dE/dx information from the DELPHI vertex detector. It will be shown in this note that the net output is much more efficient at the same purity than the HADSIGN or RIBMEAN tags alone. We present an easy-to-use routine performing the necessary calculations.

  18. Portable High Sensitivity and High Resolution Sensor to Determine Oxygen Purity Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I STTR project is to develop a highly sensitive oxygen (O2) sensor, with high accuracy and precision, to determine purity levels of high...

  19. High-performance, bare silver nanowire network transparent heaters.

    Science.gov (United States)

    Ergun, Orcun; Coskun, Sahin; Yusufoglu, Yusuf; Unalan, Husnu Emrah

    2016-11-01

    Silver nanowire (Ag NW) networks are one of the most promising candidates for the replacement of indium tin oxide (ITO) thin films in many different applications. Recently, Ag-NW-based transparent heaters (THs) showed excellent heating performance. In order to overcome the instability issues of Ag NW networks, researchers have offered different hybrid structures. However, these approaches not only require extra processing, but also decrease the optical performance of Ag NW networks. So, it is important to investigate and determine the thermal performance limits of bare-Ag-NW-network-based THs. Herein, we report on the effect of NW density, contact geometry, applied bias, flexing and incremental bias application on the TH performance of Ag NW networks. Ag-NW-network-based THs with a sheet resistance and percentage transmittance of 4.3 Ω sq(-1) and 83.3%, respectively, and a NW density of 1.6 NW μm(-2) reached a maximum temperature of 275 °C under incremental bias application (5 V maximum). With this performance, our results provide a different perspective on bare-Ag-NW-network-based transparent heaters. PMID:27678197

  20. HIGH-PURITY WATER PRODUCTION BY RO/EDI SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Electrodeionization(EDI),also known as continuous deionization(CDI)and packed-cell electrodialysis,is a novel hybrid separation process combining ion-exchange resin with ion-exchange membrane in one unit.The EDI process was discovered in the 1950's[1,2]in laboratory,the first commercial apparatus for the production of high-purity water was available in 1987[3].Now the EDI technology has been found and will be continuously found its great applications in many engineering fields. In EDI,the dilute compartments are filled with mixed-bed ion-exchange resins,which enhance the transport to the membranes under the force of a direct current.The ion transport is almost entire through the ion-exchange resins and is not effected through the water.Under certain conditions,water-splitting reaction occurs in the dilute chambers and then the relative high concentrations of H+ and OH- are able to regenerate the resins continuously, With the unique “electroregeneration",the EDI unit can be considered as a mixed-bed ion-exchange column with continuous regeneration.and therefore is capable of deep deionization.Comparing with electrodialysis and ion exchange respectively,EDI has put up much superiority in water desalination. In our experiments,the processes for production of high-purity water from tap water are consisted of pretreatment (with ultrafiltration,active carbon and 10 μm-filtration),RO and EDI.

  1. Characteristics of GRIFFIN high-purity germanium clover detectors

    Science.gov (United States)

    Rizwan, U.; Garnsworthy, A. B.; Andreoiu, C.; Ball, G. C.; Chester, A.; Domingo, T.; Dunlop, R.; Hackman, G.; Rand, E. T.; Smith, J. K.; Starosta, K.; Svensson, C. E.; Voss, P.; Williams, J.

    2016-06-01

    The Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new experimental facility for radioactive decay studies at the TRIUMF-ISAC laboratory. The performance of the 16 high-purity germanium (HPGe) clover detectors that will make up the GRIFFIN spectrometer is reported. The energy resolution, efficiency, timing resolution, crosstalk and preamplifier properties of each crystal were measured using a combination of analog and digital data acquisition techniques. The absolute efficiency and add-back factors are determined for the energy range of 80-3450 keV. The detectors show excellent performance with an average over all 64 crystals of a FWHM energy resolution of 1.89(6) keV and relative efficiency with respect to a 3 in . × 3 in . NaI detector of 41(1)% at 1.3 MeV.

  2. Cube orientation in hot rolled high purity aluminum plate

    Institute of Scientific and Technical Information of China (English)

    杨平; 毛卫民

    2003-01-01

    X-ray diffraction and orientation mapping in EBSD measurement were applied to obtain information ofdeformation and recrystallization with the emphasis on the cube orientation in hot rolled high purity aluminumplates. It is shown that cube orientations are retained to a large extent during hot rolling. Some deformed cubegrains are found to have experienced large extent of recovery according to their Kikuchi band contrasts. The de-formed cube-oriented grains in hot rolled plates are in an unfavorite growth condition with respect to their neighbor-ing grain orientations for the subsequent annealing. The reasons for the phenomena observed, as well as the influ-ence of hot rolling process on subsequent cold rolling and final annealing were discussed.

  3. Development of high purity niobium used in SRF accelerating cavity

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Niobium is widely used in SRF(Superconducting Radio Frequency)cavities due to its excellent superconductivity and workability.With the continuous development of technology,higher demands of material are raised.One of the key issues is that RRR(Residual Resistance Ratio)of the Nb material should be more than 300.which requires that the Nb ingot have even higher RRR.This article introduces the development and the experimental results of high purity niobium in OTIC in Ningxia(Ningxia Orient Tantalum Industry Co.Ltd.),and the test results of the single cell TESLA(Tera Electron volt energy Superconducting Linear Accelerator)shaped cavity manufactured by Peking University using Nb material from OTIC.

  4. Purity analyses of high-purity organic compounds with nitroxyl radicals based on the Curie–Weiss law

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Nobuhiro, E-mail: nobu-matsumoto@aist.go.jp; Shimosaka, Takuya [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), AIST Central-3, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)

    2015-05-07

    This work reports an attempt to quantify the purities of powders of high-purity organic compounds with stable nitroxyl radicals (namely, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (TEMPOL), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl benzoate (4-hydroxy-TEMPO benzoate)) in terms of mass fractions by using our “effective magnetic moment method,” which is based on both the Curie–Weiss law and a fundamental equation of electron paramagnetic resonance (ESR). The temperature dependence of the magnetic moment resulting from the radicals was measured with a superconducting quantum interference device magnetometer. The g value for each compound was measured with an X-band ESR spectrometer. The results of the purities were (0.998 ± 0.064) kg kg{sup −1} for TEMPO, (1.019 ± 0.040) kg kg{sup −1} for TEMPOL, and (1.001 ± 0.048) kg kg{sup −1} for 4-hydroxy-TEMPO benzoate. These results demonstrate that this analytical method as a future candidate of potential primary direct method can measure the purities with expanded uncertainties of approximately 5%.

  5. Purity analyses of high-purity organic compounds with nitroxyl radicals based on the Curie-Weiss law

    Science.gov (United States)

    Matsumoto, Nobuhiro; Shimosaka, Takuya

    2015-05-01

    This work reports an attempt to quantify the purities of powders of high-purity organic compounds with stable nitroxyl radicals (namely, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (TEMPOL), and 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl benzoate (4-hydroxy-TEMPO benzoate)) in terms of mass fractions by using our "effective magnetic moment method," which is based on both the Curie-Weiss law and a fundamental equation of electron paramagnetic resonance (ESR). The temperature dependence of the magnetic moment resulting from the radicals was measured with a superconducting quantum interference device magnetometer. The g value for each compound was measured with an X-band ESR spectrometer. The results of the purities were (0.998 ± 0.064) kg kg-1 for TEMPO, (1.019 ± 0.040) kg kg-1 for TEMPOL, and (1.001 ± 0.048) kg kg-1 for 4-hydroxy-TEMPO benzoate. These results demonstrate that this analytical method as a future candidate of potential primary direct method can measure the purities with expanded uncertainties of approximately 5%.

  6. A TNFR2-Agonist Facilitates High Purity Expansion of Human Low Purity Treg Cells.

    Directory of Open Access Journals (Sweden)

    Xuehui He

    Full Text Available Regulatory T cells (Treg are important for immune homeostasis and are considered of great interest for immunotherapy. The paucity of Treg numbers requires the need for ex vivo expansion. Although therapeutic Treg flow-sorting is feasible, most centers aiming at Treg-based therapy focus on magnetic bead isolation of CD4+CD25+ Treg using a good manufacturing practice compliant closed system that achieves lower levels of cell purity. Polyclonal Treg expansion protocols commonly use anti-CD3 plus anti-CD28 monoclonal antibody (mAb stimulation in the presence of rhIL-2, with or without rapamycin. However, the resultant Treg population is often heterogeneous and pro-inflammatory cytokines like IFNγ and IL-17A can be produced. Hence, it is crucial to search for expansion protocols that not only maximize ex vivo Treg proliferative rates, but also maintain Treg stability and preserve their suppressive function. Here, we show that ex vivo expansion of low purity magnetic bead isolated Treg in the presence of a TNFR2 agonist mAb (TNFR2-agonist together with rapamycin, results in a homogenous stable suppressive Treg population that expresses FOXP3 and Helios, shows low expression of CD127 and hypo-methylation of the FOXP3 gene. These cells reveal a low IL-17A and IFNγ producing potential and hardly express the chemokine receptors CCR6, CCR7 and CXCR3. Restimulation of cells in a pro-inflammatory environment did not break the stability of this Treg population. In a preclinical humanized mouse model, the TNFR2-agonist plus rapamycin expanded Treg suppressed inflammation in vivo. Importantly, this Treg expansion protocol enables the use of less pure, but more easily obtainable cell fractions, as similar outcomes were observed using either FACS-sorted or MACS-isolated Treg. Therefore, this protocol is of great interest for the ex vivo expansion of Treg for clinical immunotherapy.

  7. A TNFR2-Agonist Facilitates High Purity Expansion of Human Low Purity Treg Cells.

    Science.gov (United States)

    He, Xuehui; Landman, Sija; Bauland, Stijn C G; van den Dolder, Juliette; Koenen, Hans J P M; Joosten, Irma

    2016-01-01

    Regulatory T cells (Treg) are important for immune homeostasis and are considered of great interest for immunotherapy. The paucity of Treg numbers requires the need for ex vivo expansion. Although therapeutic Treg flow-sorting is feasible, most centers aiming at Treg-based therapy focus on magnetic bead isolation of CD4+CD25+ Treg using a good manufacturing practice compliant closed system that achieves lower levels of cell purity. Polyclonal Treg expansion protocols commonly use anti-CD3 plus anti-CD28 monoclonal antibody (mAb) stimulation in the presence of rhIL-2, with or without rapamycin. However, the resultant Treg population is often heterogeneous and pro-inflammatory cytokines like IFNγ and IL-17A can be produced. Hence, it is crucial to search for expansion protocols that not only maximize ex vivo Treg proliferative rates, but also maintain Treg stability and preserve their suppressive function. Here, we show that ex vivo expansion of low purity magnetic bead isolated Treg in the presence of a TNFR2 agonist mAb (TNFR2-agonist) together with rapamycin, results in a homogenous stable suppressive Treg population that expresses FOXP3 and Helios, shows low expression of CD127 and hypo-methylation of the FOXP3 gene. These cells reveal a low IL-17A and IFNγ producing potential and hardly express the chemokine receptors CCR6, CCR7 and CXCR3. Restimulation of cells in a pro-inflammatory environment did not break the stability of this Treg population. In a preclinical humanized mouse model, the TNFR2-agonist plus rapamycin expanded Treg suppressed inflammation in vivo. Importantly, this Treg expansion protocol enables the use of less pure, but more easily obtainable cell fractions, as similar outcomes were observed using either FACS-sorted or MACS-isolated Treg. Therefore, this protocol is of great interest for the ex vivo expansion of Treg for clinical immunotherapy. PMID:27224512

  8. Differential Diode Laser Sensor for High-Purity Oxygen Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A compact portable sensor for determining the purity of oxygen concentrations near 100 percent is proposed based on differential absorption of two beams from a...

  9. Bright Photon Pair Source with High Spectral and Spatial Purity

    International Nuclear Information System (INIS)

    Spontaneous parametric down-conversion (SPDC) is a reliable and robust source of photons for quantum information applications. For applications that involve operations such as entanglement swapping or single-photon heralding, two-photon states are required to be factorable (uncorrelated) in their spectral and spatial degrees of freedom. We report the design and experimental characterization of an SPDC source that has been optimized for high spectral and spatial purity. The source is pumped by the 776 nm output of a mode-locked Ti:Sapphire laser and consists of a periodically-poled Potassium Titanyl Phosphate (PPKTP) crystal phase-matched for collinear type-II SPDC. The dispersive properties of PPKTP at these wavelengths is such that it is possible to minimize the spectral entanglement by matching the widths of the pump to the spectral phase-matching function. The spatial entanglement is minimized through careful control of the pump focus, yielding nearly single-mode emission. An advantage of this approach is that the emission rate into the collection modes is very high, resulting in a very bright SPDC source. We also report a scheme that employs the output of collinear sources such as these to produce polarization-entangled photon pairs. The scheme, which requires only simple polarization elements, can be scaled to N-photon GHZ states.

  10. The Status Quo and Development Trend of High-purity Gold Sputtering Targets

    Institute of Scientific and Technical Information of China (English)

    YANG Anheng; XIE Hongchao; ZHU Yong

    2012-01-01

    This article gives a brief introduction to manufacturers and markets of sputtering targets as well as the manufacturing technology thereof.Then,it analyzes the application of high-purity gold sputtering targets in the fields of integrated circuit,information storage,flat panel display,etc.Based on the above,the article analyzes the processing development trend for the high-purity gold sputtering targets in aspects of ultra-high purity,manufacturing technology,analysis and testing technologies.

  11. The determination of boron in aluminium of high purity

    International Nuclear Information System (INIS)

    A description is given of the investigations that led to the development of chemical methods for the determination of boron within the range 0,25 to 1,0 p.p.m. in aluminium of high purity. Methods were developed that incorporated fluorimetry, directly in solutions containing aluminium and after separation of boron by liquid-liquid extraction into 2-ethyl-1,3 hexanediol. A published spectrophotometric method, involving extraction of the BF4sup(-) complex with methylene blue into dichloroethane, was modified for application to alluminium samples. Details of this modified procedure and the fluorimetric-extraction procedure are appended. The precision of the methylene-blue method is about 6 percent relative and is recommended for precision and speed in preference to others. Separation of boron by distillation and spectrophotometric determination with curcumin gave low values in comparison with those obtained by the other methods. Agreement between the boron values obtained on the samples tested was good for the fluorimetric and methylene-blue spectrophotometric methods

  12. Development of high purity vanadium alloys for fusion reactors

    International Nuclear Information System (INIS)

    Vanadium alloys are most attractive candidate materials for liquid Li self-cooled blanket system of fusion reactors. This paper summarizes the program and its activities of the NIFS (National Institute for Fusion Science), Japan for developments of high purity V-4Cr-4Ti alloys. The results from NIFS-Heats show various benefits by reducing the level of oxygen. Significant improvement of the impact properties of the welded joint by reducing oxygen level is one of examples in recent studies. Collaboration is in progress, in which those heats are being characterized by a number of research groups including Japanese universities, and international collaboration partners in the US, Russia and China. The impact tests of irradiated specimens are in progress for further investigation. Significant progress has been made recently on the insulator ceramic coating in static conditions in the Japan-USA Cooperation Program. The understanding on the condition of in-situ CaO coating in liquid Li was enhanced. Based on these achievements, a flowing loop test is being planned to investigate the effects of temperature gradient and Li chemistry. (Y. Tanaka)

  13. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    K L Ramakumar

    2005-07-01

    Available analytical literature reveals that it is possible to identify a lot of procedures to carry out any determination using a plethora of analytical techniques. The fundamental analytical requirements for realizing the desired and acceptable information from a chemical analysis are representative nature of the sample, precision, accuracy, selectivity and sensitivity. These decide, to a larger extent, the selection of the most appropriate methodology in order to obtain chemical information from a system. A number of analytical methodologies are being used in the author’s laboratory for carrying out trace elemental analysis as a part of chemical quality control. Quite a good number of analytical challenges with specific reference to the characterization of high purity materials of relevance to nuclear technology were addressed and methodologies were developed for trace elemental analysis of both metallic and non-metallic constituents. A brief review of these analytical challenges and the analytical methodologies developed and also the future needs of analytical chemist are presented in this paper.

  14. The Hydrometallurgical Extraction and Recovery of High-Purity Silver

    Science.gov (United States)

    Hoffmann, James E.

    2012-06-01

    -bearing inputs, will be described in detail to demonstrate how typical chemical engineering unit process and unit operations have supplanted classic smelting and fire refining techniques. The Kennecott Copper Company, which has operated a hydrometallurgical circuit successfully for the recovery of high-purity silver from the slimes wet chlorination residue, has permitted me to provide some operation information and results using the technology. Both Phelps Dodge and Kennecott should be recognized for their forward-looking attitude in undertaking the conversion of conceptual chemistry into successful, full-scale plants. The process as employed at Phelps Dodge is discussed at length in reference (J.E. Hoffmann and B. Wesstrom: Hydrometallurgy, 1994, vol. 94, pp. 69-105).

  15. Corrosion of high purity Fe-Cr-Ni alloys in 13 N boiling nitric acid

    International Nuclear Information System (INIS)

    Corrosion in boiling nitric acid was investigated for high purity Fe-18%Cr-12%Ni alloys and type 304L stainless steels (SS). Owing to very low impurity concentration, the solution treated high purity alloys show almost no intergranular corrosion while the type 304L SS show severe intergranular corrosion. Both in the high purity alloys and type 304L SS, aging treatments ranging from 873 K to 1073 K for 1 h enhance intergranular corrosion. During the aging treatments, impurities should be segregated to the grain boundaries. The corrosion behaviors were discussed from a standpoint of impurity segregation to grain boundaries. This study is of importance for purex reprocessing of spent fuels

  16. A cleaner two-step synthesis of high purity diallyldimethylammonium chloride monomers for flocculant preparation

    Institute of Scientific and Technical Information of China (English)

    TIAN Bing-hui; FAN Bin; PENG Xian-jia; LUAN Zhao-kun

    2005-01-01

    In order to improve the flocculation efficiency of polydiallyldimethylammonium chloride (PDADMAC), high molecular weight PDADMAC should be prepared from high purity diallyldimethylammonium chloride(DADMAC) monomers. In this paper, a cleaner method with microwave irradiation and alkali solidification was proposed for preparing high pure DADMAC by selective heating under low temperature, and the prepared high purity DADMAC is characterized using FTIR and atomic absorption spectrometry. The new method provides a solution to the key technical problem of PDADMAC synthesis. Comparing with the conventional methods, the results showed that the advantages of the novel synthesis include: (a) high purity DADMAC is improved from 57% to 71%; (b) reaction time of tertiary amine preparation is shortened from 6 h to 7 min; (c) water instead of acetone was used as reaction medium; (d) toxic by-products,wastewater and waste gas are eliminated. Flocculant made from the synthesized high purity DADMAC monomers was proved more efficient in flocculation tests.

  17. A cleaner two-step synthesis of high purity diallyldimethylammonium chloride monomers for flocculant preparation.

    Science.gov (United States)

    Tian, Bing-hui; Fan, Bin; Peng, Xian-jia; Luan, Zhao-kun

    2005-01-01

    In order to improve the flocculation efficiency of polydiallyldimethylammonium chloride (PDADMAC), high molecular weight PDADMAC should be prepared from high purity diallyldimethylammonium chloride(DADMAC) monomers. In this paper, a cleaner method with microwave irradiation and alkali solidification was proposed for preparing high pure DADMAC by selective heating under low temperature, and the prepared high purity DADMAC is characterized using FTIR and atomic absorption spectrometry. The new method provides a solution to the key technical problem of PDADMAC synthesis. Comparing with the conventional methods, the results showed that the advantages of the novel synthesis include: (a) high purity DADMAC is improved from 57% to 71%; (b) reaction time of tertiary amine preparation is shortened from 6 h to 7 min; (c) water instead of acetone was used as reaction medium; (d) toxic by-products, wastewater and waste gas are eliminated. Flocculant made from the synthesized high purity DADMAC monomers was proved more efficient in flocculation tests. PMID:16313006

  18. Deformation behaviour of fine grained high purity beryllium - influence of fabrication parameters, temperature and copper additions

    International Nuclear Information System (INIS)

    The deformation behaviour of high-purity beryllium was tested on hot isostatically pressed samples of different initial grain size and compared with material manufactured commercially from pure beryllium and with beryllium-copper alloys containing 0.44, 1.1 and 2.1 at.% copper. Initial grain size of these high purity material was 0C. Grain structure of the samples was subsequently analysed by light, rastor and transmission electron microscopy. The influence of copper additions on deformation of high-purity beryllium was analysed. A further aim of this study was to investigate, by suitable methods, the mode of action of relevant impurities and to throw light on their influence on grain formation. This should enable reliable information to be provided for the manufacture of high-purity beryllium which, in turn, will lead to an improvement in ductility. (orig./IHOE)

  19. Preparation of high-purity tantalum ethoxide by vacuum distillation

    Institute of Scientific and Technical Information of China (English)

    YANG Sheng-hai; CHEN Yong-ming; YANG Hai-ping; LIU Yin-yuan; TANG Mo-tang; QIU Guan-zhou

    2008-01-01

    Effects of reflux ratio, water addition and content of water in ethanol on the purity and yield of tantalum ethoxide during vacuum distillation were investigated under the operational conditions of pressure of 1 kPa, oil bath temperature of 210-230 ℃, and outlet temperature of 190 ℃. The condensate sample was characterized by FTIR, 1H-NMR spectroscopy and Raman spectra, respectively. The contents of tantalum, carbon and hydrogen in the sample were also determined with elemental analysis instrument. The obtained results consistently demonstrate that the condensate is tantalum ethoxide. The content of impurity, such as Al, As, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sn, Ti, V and Zn, in tantalum ethoxide is less than 0.000 05%, while Nb content is less than 0.000 5%. The content of impurities in tantalum ethoxide sample excels that of Epichem Group's requirement for Ta(OC2H5)5 of 99.999%.

  20. Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen

    Science.gov (United States)

    Hornung, Steven

    2013-01-01

    Oxygen used for extravehicular activities (EVAs) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen has been developed. This instrument uses a glow discharge in reduced-pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete, and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants, and may lend itself to a device capable of on-orbit verification of oxygen purity. A glow discharge is a plasma formed in a low-pressure (1 to 10 Torr) gas cell between two electrodes. Depending on the configuration, voltages ranging from 200 V and above are required to sustain the discharge. In the discharge region, the gas is ionized and a certain population is in the excited state. Light is produced by the transitions from the excited states formed in the plasma to the ground state. The spectrum consists of discrete, narrow emission lines for the atomic species, and broader peaks that may appear as a manifold for molecular species such as O2 and N2, the wavelengths and intensities of which are a characteristic of each atom. The oxygen emission is dominated by two peaks at 777 and 844 nm.

  1. Hot ductility and high temperature microstructure of high purity iron alloys

    International Nuclear Information System (INIS)

    The inherent properties of metals are affected by impurity elements, sometimes strongly. There are many brittle phenomena in iron and its alloys due to the harmful effect of trace impurities such as sulphur, phosphorus, hydrogen and so on. On the other hand, a large number of alloying elements also embrittle iron due to the transformation and precipitation of secondary phase. For example, the ductility of Fe-Cr alloy decreases with the increase in chromium content, although the strength and the corrosion resistance increase with chromium content. In Fe-Cr alloy containing high chromium, 475 C embrittlement and σ-phase embrittlement are well known. An Fe-50mass%Cr alloy of conventional purity is extremely brittle due to the formation of σ-phase. However, we found the highly purified alloy is essentially ductile. In the workshop of UHPM-94, the experimental results on the ductility of Fe-50mass%Cr alloy were presented and discussed. In this research, the effect of purification on the hot ductility of high purity Fe-18mass%Cr and Fe-50mass%Cr alloys was investigated by tensile testing at high temperature. It was found that the ductility of Fe-18mass%Cr alloy is remarkably improved by purification, especially by the reduction of interstitial impurities such as carbon and nitrogen. The highly-purified Fe-50mass%Cr alloy has astonishing ductility at the temperature range between room temperature and 1073K. Also in a high purity Fe-50mass%Cr alloy, the formation of the σ-phase was not observed during ageing for 1000h at 973K. These results are also very important for the development of high-performance Fe-Cr alloys and of the manufacturing process. Consequently, purification technology is very useful for progress in metal science. (orig.)

  2. Production of high purity electronic materials at Special Materials Plant (Paper No. 45)

    International Nuclear Information System (INIS)

    Special Materials Plant of the Nuclear Fuel Complex, Hyderabad, produces a number of high purity/ultrapurity metals and materials for use in electronics industry. Based on the laboratory scale R and D efforts at Bhabha Atomic Research Centre, Bombay, this plant was set up at Nuclear Fuel Complex involving a capital outlay of approximately Rs. 5 millions and has been under operation for over 5 years. The experience gathered during the process of the transfer of the R and D to production in this sophisticated high technology areas is described. Among its important products are included capacitor grade sintered tantalum anodes, ultrapure materials like selenium, indium, etc., and also many other metals used in electronics industry in smaller quantities. The plant makes use of many production techniques, the important ones of which are: (a) multi-stage liquid-liquid extraction for separation of niobium and tantalum, (b) pyro-metallurgical reduction techniques, (c) distillation of metals in vacuum, (f) zone refining, (g) electron refining etc. Whereas in the case of tantalum the purity of the final product is about 99.99% in other cases like selenium, indium, tellurium, etc. the purity exceeds 99.999%. For gallium the purity almost approaches 99.9999% particularly, with respect to electrically active impurities. Experience at Special Materials Plant has generated significant confidence in the High Purity Materials Development Programme. (auth.)

  3. Influence of recrystallization annealing on the cube texture in high-purity aluminum foils

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.M.; Tang, J.G.; Du, Y.X.; Zhou, Z.P.; Chen, Z.Y.; Liu, C.M. [Dept. of Materials Science and Engineering, Central South Univ., HN (China)

    2001-07-01

    The cube texture in high-purity aluminum foils under different annealing conditions was investigated by means of orientation distribution function (ODF) and microscopy. It was shown that low recrystallization temperature was favorable to the nucleation of cube orientation and to the growth of the cube nuclei, and that stronger cube texture was obtained by multistage annealing than by single one. The strongest cube texture in high purity aluminum foils annealed in two-stage in the vacuum was obtained. It demonstrated that the recrystallization behavior was controlled by the existing state of Fe in aluminum. A model of multistage annealing was proposed for development of strong cube texture with temperature. (orig.)

  4. Growth of high purity semiconductor epitaxial layers by liquid phase epitaxy and their characterization

    Indian Academy of Sciences (India)

    S Dhar

    2005-07-01

    This paper briefly describes our work and the results on the growth of several III–V epitaxial semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique. Various possible sources of impurities in such growth are listed and step-by-step procedures adopted to reduce them are discussed in particular reference to the growth of GaAs layers. The technique of growing very high purity layers by treating the melt with erbium is described for the growth of InGaAs and GaSb layers.

  5. High-Purity Fe3S4 Greigite Microcrystals for Magnetic and Electrochemical Performance

    NARCIS (Netherlands)

    Li, Guowei; Zhang, Baomin; Yu, Feng; Novakova, Alla A.; Krivenkov, Maxim S.; Kiseleva, Tatiana Y.; Chang, Liao; Rao, Jiancun; Polyakov, Alexey O.; Blake, Graeme R.; de Groot, Robert A.; Palstra, Thomas T. M.

    2014-01-01

    High-purity Fe3S4 (greigite) microcrystals with octahedral shape were synthesized via a simple hydrothermal method using a surfactant. The as-prepared samples have the inverse spinel structure with high crystallinity. The saturation magnetization (M-s) reaches 3.74 mu(B) at 5 K and 3.51 mu(B) at roo

  6. Characterization of segmented large volume, high purity germanium detectors

    International Nuclear Information System (INIS)

    γ-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple γ-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics. The results are

  7. Characterization of segmented large volume, high purity germanium detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bruyneel, B. [Koeln Univ. (Germany). Inst. fuer Kernphysik

    2006-07-01

    {gamma}-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple {gamma}-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by {gamma}-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics

  8. Optical levitation of high purity nanodiamonds in vacuum without heating

    CERN Document Server

    Frangeskou, A C; Gines, L; Mandal, S; Williams, O A; Barker, P F; Morley, G W

    2016-01-01

    Levitated nanodiamonds containing nitrogen vacancy centres in high vacuum are a potential test bed for numerous phenomena in fundamental physics. However, experiments so far have been limited to low vacuum due to heating arising from optical absorption of the trapping laser. We show that milling pure diamond creates nanodiamonds that do not heat up as the optical intensity is raised above 700 GW/m$^2$ below 5 mbar of pressure. This advance now means that the level of attainable vacuum for nanodiamonds in optical dipole traps is no longer temperature limited.

  9. Preparation of high purity plutonium oxide standards for radiochemical Analysis

    International Nuclear Information System (INIS)

    Due to the lack of suitable high level plutonium solution standards from a national accredited laboratory or commercial vendors, a well-characterized plutonium oxide was used to prepared radiochemistry instrument calibration standards and working standards at Los Alamos National Laboratory (LANL). All the dilution and aliquoting steps were performed gravimetrically. The counting efficiency of a liquid scintillation counter obtained from the alpha activity of this plutonium oxide was compared to a commercial 241Am standardized solution. The results agreed to within 0.05%. The aliquots of the plutonium standard solutions and dilutions were then sealed in glass ampules for long term storage

  10. Recovery of high purity precious metals from printed circuit boards

    International Nuclear Information System (INIS)

    Waste printed circuit boards (WPCB) have an inherent value because of the precious metal content. For an effective recycling of WPCB, it is essential to recover the precious metals. This paper reports a promising method to recover the precious metals. Aqua regia was used as a leachant and the ratio between metals and leachant was fixed at 1/20 (g/ml). Silver is relatively stable so the amount of about 98 wt.% of the input was recovered without an additional treatment. Palladium formed a red precipitate during dissolution, which were consisted of Pd(NH4)2Cl6. The amount precipitated was 93 wt.% of the input palladium. A liquid-liquid extraction with toluene was used to extract gold selectively. Also, dodecanethiol and sodium borohydride solution were added to make gold nanoparticles. Gold of about 97 wt.% of the input was recovered as nanoparticles which was identified with a high-resolution transmission electron microscopy through selected area electron diffraction and nearest-neighbor lattice spacing.

  11. Thermodynamic analysis of production of high purity titanium by thermal decomposition of titanium iodide

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-hu; WANG Hua; LIU Yi-min; FANG Min

    2009-01-01

    High purity titanium was prepared by thermal decomposition of titanium iodide. The feasible synthetic route and optimum decompositon temperaure were obtained by thermodynamic analysis in the process of thermal decomposition of titanium iodide and nucleation growth theory. The temperature for the formation of titanium iodide is in the range of 800-900 K, at which a large amount of titanium iodide vapour can be obtained. The decomposition temperature of titanium iodide is in the range of 1 300-1 500 K, at which a favourable decomposition rate can be achieved. The experiment results show that the purity of the produced titanium is more than 99.995%.

  12. Scalable preparation of high purity rutin fatty acid esters following enzymatic synthesis

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing;

    2010-01-01

    -up biosynthesis reactions was established. Acylation reactions of rutin and palmitic or lauric acids were efficient in systems containing dried acetone and molecular sieves, yielding from 70–77% bioconversion after 96 h. Thereafter, high purity isolates (>97%) were easily obtained in significant quantities...

  13. Integration of High-Purity Carbon Nanotube Solution into Electronic Devices

    Science.gov (United States)

    Tulevski, George; IBM TJ Watson Reserach Center Team

    Due to their exceptional electronic properties, carbon nanotubes (cnt) are leading candidates to be employed as channel materials in future nanoelectronic devices. A key bottleneck to realizing device integration is the sorting of carbon nanotubes, namely the isolation of high-purity, semiconducting cnt solutions. This talk will describe our efforts in using polymer-based sorting methods to isolate high-density and high-purity semiconducting cnt solutions. We explore the dependence of starting material and polymer to cnt ratio on the effectiveness of the separation. We confirm optically and electrically that the semiconducting purity is >99.99% through several thousand individual device measurements. In addition to single-cnt devices, thin-film transistors were also fabricated and tested. Due to the high purity of the solutions, device switching (~105 ION/IOFF) was observed at channel lengths below the percolation threshold (<500 nm). Operating below the percolation threshold allows for devices with much higher current densities and effective mobilities as transport is now the result of direct transport as opposed to hopping between cnts.

  14. Structure and texture of electrolytic superconducting coatings of high-purity niobium

    Science.gov (United States)

    Kolosov, V. N.; Shevyrev, A. A.

    2014-08-01

    Modes of epitaxial growth of electrolytic superconducting coatings of high-purity niobium on substrates of niobium, molybdenum, and tungsten have been investigated. The dynamics of changes in the structure and texture of the coatings depending on the method of treatment of substrates, cathode current density, and thickness of the deposited niobium layer has been studied.

  15. Preparation of uranium-plutonium mixed nitride pellets with high purity

    International Nuclear Information System (INIS)

    Uranium-plutonium mixed nitride pellets have been prepared in the gloveboxes with high purity Ar gas atmosphere. Carbothermic reduction of the oxides in N2-H2 mixed gas stream was adopted for synthesizing mixed nitride. Sintering was carried out in various conditions and the effect on the pellet characteristics was investigated. (author)

  16. Fused salt processing of impure plutonium dioxide to high-purity plutonium metal

    International Nuclear Information System (INIS)

    A process for converting impure plutonium dioxide (approx. 96% pure) to high-purity plutonium metal (>99.9%) was developed. The process consists of reducing the oxide to an impure plutonium metal intermediate with calcium metal in molten calcium chloride. The impure intermediate metal is cast into an anode and electrorefined to produce high-purity plutonium metal. The oxide reduction step is being done now on a 0.6-kg scale with the resulting yield being >99.5%. The electrorefining is being done on a 4.0-kg scale with the resulting yield being 80 to 85%. The purity of the product, which averages 99.98%, is essentially insensitive to the purity of the feed metal. The yield, however, is directly dependent on the chemical composition of the feed. To date, approximately 250 kg of impure oxide has been converted to pure metal by this processing sequence. The availability of impure plutonium dioxide, together with the need for pure plutonium metal, makes this sequence a valuable plutonium processing tool

  17. High purity materials as targets for radioisotope production: Needs and challenges

    Indian Academy of Sciences (India)

    V Shivarudrappa; K V Vimalnath

    2005-07-01

    Radionuclides have become powerful and indispensable tools in many endeavours of human activities, most importantly in medicine, industry, biology and agriculture, apart from R&D activities. Ready availability of radionuclides in suitable radiochemical form, its facile detection and elegant tracer concepts are responsible for their unprecedented use. Application of radioisotopes in medicine has given birth to a new branch, viz. nuclear medicine, wherein radioisotopes are used extensively in the diagnosis and treatment of variety of diseases including cancer. Artificial transmutation of an element employing thermal neutrons in a reactor or high energy particle accelerators (cyclotrons) are the routes of radioisotope production world over. Availability of high purity target materials, natural or enriched, are crucial for any successful radioisotope programme. Selection of stable nuclides in suitable chemical form as targets with desired isotopic and chemical purity are among the important considerations in radioisotope production. Mostly the oxide, carbonate or the metal itself are the preferred target forms for neutron activation in a research reactor. Chemical impurities, particularly from the elements of the same group, put a limitation on the purity of the final radioisotope product. Whereas the isotopic impurities result in the production of undesirable radionuclidic impurities, which affect their effective utilization. Isotope Group, BARC, is in the forefront of radioisotope production and supply in the country, meeting demands for gamut of radioisotope applications indigenously for over four decades now. Radioisotopes such as 131I, 99Mo, 32P, 51Cr, 153Sm, 82Br, 203Hg, 198Au etc are produced in TBq quantities every month and supplied to several users and to Board of Radiation and Isotope Technology (BRIT). Such a large production programme puts a huge demand on the reliable sources of availability of high purity target materials which are at present mostly met

  18. Preparation and Characterization of High Purity Enriched10B Boric Acid via Anti-Solvent Recrystallization

    Institute of Scientific and Technical Information of China (English)

    张卫江; 刘天雨; 徐姣

    2016-01-01

    Self-made enriched10B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5,℃and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.

  19. Preparation and characterization of (10)B boric acid with high purity for nuclear industry.

    Science.gov (United States)

    Zhang, Weijiang; Liu, Tianyu; Xu, Jiao

    2016-01-01

    Boric acid is often added into coolant as neutron capture agent for pressurized water reactor, whose amount is influenced by its abundance and purity. Therefore, the preparation of enriched (10)B boric acid with high purity is beneficial to nuclear industry. (10)B is also used in developing tumor-specific boronated drugs in boron neutron capture therapy. The boronated drug can be administered to patient intravenously, intratumorally, or deposited at tumor site in surgical excision. Thus, enriched (10)B boric acid is of practical significance in the field of medicine. Self-made boron trifluoride-methanol-complex solution was selected as one of the experimental reagents, and the preparation of (10)B acid was realized by one-step reaction for the complexes with water and calcium chloride. The determination of electrical conductivity in reaction process proves that the optimum reaction time was 16-20 h. Furthermore, the effect of reaction time, ratio of calcium chloride to complex as well as the amount of water on the purity and yield of boric acid was investigated. Finally, the optimum reaction time was 20 h, the optimal solid-liquid ratio (molar ratio) was 3:1, and the amount of water was 1 L of deionized water for each mol of the complex. H2O2 was added in the reaction process to remove Fe(2+). After recrystallization, IR spectra of (10)B boric acid was measured and compared with standard to verify the product of boric acid. The feasibility of the preparation method was determined by the detection of XRD of boric acid. To observe the morphology by polarizing microscope, crystal structure was obtained. The purity of the final product is 99.95 %, and the yield is 96.47 %. The ion concentration of boric acid accords with the national standard of high purity, which was determined by ICP.

  20. A Study of the Surface Quality of High Purity Copper after Heat Treatment

    CERN Document Server

    Aicheler, M; Atieh, S; Calatroni, S; Riddone, G; Lebet, S; Samoshkin, A

    2011-01-01

    Themanufacturing flow of accelerating structures for the compact linear collider, based on diamond-machined high purity copper components, include several thermal cycles (diffusion bonding, brazing of cooling circuits, baking in vacuum, etc.). The high temperature cycles may be carried out following different schedules and environments (vacuum, reducing hydrogen atmosphere, argon, etc.) and develop peculiar surface topographies which have been the object of extended observations. This study presents and discusses the results of scanning electron microscopy (SEM) and optical microscopy investigations.

  1. Charge particle activation analysis of light element impurities in high purity materials

    International Nuclear Information System (INIS)

    Charged particle activation analysis (CPAA) of low Z element impurities like oxygen, carbon, nitrogen, boron etc. can be determined with high sensitivity and accuracy in high purity materials at ppm to ppb levels. The oxygen and carbon impurities in ppm levels have been determined in high purity metals like copper, silicon, stainless steel, tantalum, magnesium and aluminium using 40 MeV alpha-charge particles at Variable Energy Cyclotron Centre, Calcutta. Radiochemical separations were carried out to separate the radioactive products 18F and 11C formed by the nuclear reaction 16O (α pn) 18F and 12C (α, αn) 11C, respectively. Determination of carbon by deuteron activation is also studied using the nuclear reaction12C(d,n) 13N. (author). 4 refs., 1 tab

  2. Plating of iridium for use as high purity electrodes in the assay of ultrapure copper

    International Nuclear Information System (INIS)

    Fabrication of high-purity iridium electrodes using electrochemical deposition was performed to produce anodes used to assay ultrapure copper for extremely low uranium and thorium contamination primarily in support of the Majorana collaboration. High-purity iridium was deposited using a low current density under a constant voltage to produce a smooth film over a micron thick. The current efficiency was 23 % using an electrolyte of 40 mM IrCl3 · 4H2O, and H2SO4 employing polished iridium wires as electrodes at an elevated temperature of 80 deg C. The electrodes can be converted to iridium oxide with different oxidation states by heating them in air for various periods. (author)

  3. Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

    Science.gov (United States)

    Kumar, Nirmal; Biswas, Krishanu

    2015-08-01

    The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

  4. Effect of trace yttrium on cube texture of high-purity aluminum foils

    Institute of Scientific and Technical Information of China (English)

    刘楚明; 张新明; 陈志永; 蒋红辉; 周卓平

    2001-01-01

    The effect of trace yttrium on cube texture of high-purity aluminum foils has been investigated by means of orientation distribution functions (ODFs). The results show that a small addition of yttrium to high-purity aluminum brings about a considerable increment of the cube texture, and it reduces the content of R texture. The rare earth yttrium may combine with the other impurities to form the metallic compounds, such as FeYAl8, Fe6YAl6, Fe4YAl8 and Si2YAl2. When the precipitation of these particles in the matrix is nearly completed and the Fe concentration in the matrix becomes low, the cube texture can develop well and the R texture can be suppressed.

  5. Synthesis and Characterization of High-Purity Tellurium Nanowires via Self-seed-Assisted Growth Approach

    Science.gov (United States)

    Li, Ying; Zhao, Wen-yu; Mu, Xin; Liu, Xing; He, Dan-qi; Zhu, Wan-ting; Zhang, Qing-jie

    2016-03-01

    Nanowires have attracted intense attention in recent years due to their novel physical properties. In this work, we prepare high-purity tellurium nanowires through the self-seed-assisted growth method previously developed by us. The tellurium seeds were firstly synthesized by reducing Na2TeO3 in the ice water with NaBH4. The high-purity tellurium nanowires with a diameter of 40-50 nm and a length of several tens of micrometers were then grown on tellurium seeds by reducing Na2TeO3 with hydrazine hydrate. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to characterize the crystal structure, microstructure, and growth direction of tellurium seeds and nanowires. The effects of temperature, time, surfactant and tellurium seeds on microstructures of tellurium nanowires has also been investigated. The synthesis conditions of tellurium seeds and nanowires was optimized. The selected area electron diffraction pattern confirms that the growth direction of tellurium nanowires is parallel to [0001] direction. It was discovered that high-purity tellurium nanowires with high aspect ratio can be synthesized by precisely controlling the temperature to adjust the nucleation rate of the tellurium nuclei, selecting the appropriate surfactant to induce the coordination along the macromolecular chain, and using tellurium seeds as the templates of the epitaxial growth of tellurium nuclei.

  6. Determination of Trace Iron in High Purity Sodium Fluoride by Graphite Furnace Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that the ashing temperature can be increased to 1 400°C and matrix interferences eliminated, the sensi tivity of iron increased in 1.27 fold by the addition of nickel nitrate. The method is applied to the determina tion of iron in sodium fluoride and satisfactory results are obtained.

  7. Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

    Science.gov (United States)

    Reed, R. P.

    1972-01-01

    The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

  8. High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

    OpenAIRE

    Han Chulwoong; Na Hyunwoong; Choi Hanshin; Kim Yonghwan

    2015-01-01

    Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungs...

  9. The determination of boron in high-purity aluminium metal by spark-source mass spectrometry

    International Nuclear Information System (INIS)

    A method is described for the determination of boron in high-purity aluminium metal. Both isotopic boron lines (10B+1 and 11B+1) are used for the analysis. As there are no low-abundance isotopic lines for aluminium, measurements were made direct without reference to aluminium as an internal standard. The boron concentration values of eight aluminium samples analysed by this method compared favourably with results obtained from other techniques

  10. Ceramic materials for obtaining of high-purity niobium and tantalum compounds

    International Nuclear Information System (INIS)

    Meterial, based on quartz ceramics with protective coating of niobium pentaoxide, has been developed. It can be used for manufacture of containers, lining and structural products, designated for operation under conditions of rapid temperature drops and in corrosive medium, containing fluoride vapors. Such products can be used instead of platinum containers in synthesis of high-purity niobium and tantalum pentaoxide and can be recommended for application in chemical industry

  11. Formation of High-Purity Indium Oxide Nanoparticles and Their Application to Sensitive Detection of Ammonia

    OpenAIRE

    Bhardwaj, Sanjeev K.; Neha Bhardwaj; Manil Kukkar; Sharma, Amit L.; Ki-Hyun Kim; Akash Deep

    2015-01-01

    High-purity In2O3 nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These In2O3 nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed...

  12. High-purity germanium detector ionization pulse shapes of nuclear recoils, gamma interactions and microphonism

    OpenAIRE

    Baudis, L.; Hellmig, J.; Klapdor-Kleingrothaus, H. V.; Ramachers, Y.; Hammer, J. W.; Mayer, A.

    1999-01-01

    Nuclear recoil measurements with high-purity Germanium detectors are very promising to directly detect dark matter candidates. The main background sources in such experiments are natural radioactivity and microphonic noise. Digital pulse shape analysis is an encouraging approach to reduce the background originating from the latter. To study the pulse shapes of nuclear recoil events we performed a neutron scattering experiment, which covered the ionization energy range from 20 to 80 keV. We ha...

  13. Corrosion behavior of high purity Fe-Cr-Ni alloys in trans-passive condition

    International Nuclear Information System (INIS)

    The corrosion behavior of high-purity (99.99%) Fe-Cr-Ni alloys was investigated in 13 N nitric acid with/without Ce4+ ions to clarify the effect of impurities on the trans-passive corrosion of stainless steel. The following results were obtained. (1) Almost no intergranular corrosion was observed in the high-purity alloys, although the corrosion rate of the matrix region was nearly the same as that of a commercial stainless steel with the same Cr and Ni content. (2) Due to the improved intergranular corrosion resistance, the effect of the purification became significant in the corrosion condition with the grain-separation being predominant. (3) The high-purity alloys showed higher susceptivility to intergranular corrosion with aging treatment between 873 K and 1073 K. Although the sulfuric acid/copper sulfate test suggested the formation of Cr-depleted zones, a grain boundary micro-analysis using a FETEM with an EDX did not reveal any change in Cr content or impurity segregain along the grain boundaries. The mechanism of corrosion enhancement resulting from the aging treatment remains nuclear. (author)

  14. Effect of high-temperature heat treatment duration on the purity and microstructure of MWCNTs

    Indian Academy of Sciences (India)

    I Srikanth; N Padmavathi; P S R Prasad; P Ghosal; R K Jain; Ch Subrahmanyam

    2016-02-01

    The effect of high-temperature heat treatment on purity and structural changes of multiwalled carbon nanotubes (MWCNTs) were studied by subjecting the raw MWCNTs (pristine MWCNTs) to 2600°C for 60 and 120 min. Thermogravimetric analysis (TGA), X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the effect of heat-treatment duration on the purity and structural changes of MWCNTs. Results show that high-temperature heat treatment can be used to purify MWCNTs with proper optimization of treatment time. It was observed that 60 min heat treatment of raw MWCNTs imparts high purity and structural perfection to MWCNTs, while 120 min heat treatment imparts structural degradation to MWCNTs with collapse of the innermost shells. The present study indicates that metal impurities act as moderators in controlling the degradation of MWCNTs up to certain duration, and once the metal impurities escape completely, further heat treatment degrades the structure of MWCNTs.

  15. The thermal properties of high purity and fully dense tungsten produced by chemical vapor deposition

    International Nuclear Information System (INIS)

    Highlights: • High purity and fully dense CVD-W samples were prepared. • The deposition rate of CVD-W is higher than 0.6 mm/h. • Thermal conductivity of CVD-W is higher than that of forged-W. • CVD-W had a higher threshold energy of crack initiation than that of forged W. • CVD-W has higher energy absorption than that of forged-W. - Abstract: The ultra-high purity (>99.9999 wt.%) and fully dense (19.23 g/cm3) tungsten (W) by chemical vapor deposition (CVD) was prepared with the deposition rate higher than 0.6 mm/h. The thermal diffusivity, specific heat, heat conductivity and coefficient of thermal expansion of CVD-W at the temperature range of 473–1273 K were measured. Thermal shock tests were carried out on a 60 kW electron-beam material testing scenario to investigate the crack-resistant performance of CVD-W, and the crack initiation threshold energies of CVD-W were achieved in 5 ms heating duration. Compared to forged-W, the higher heat conductivity (160.5–111 W/(m K)) and threshold energy of crack initiation (1.1–1.65 MJ/m2) of CVD-W can be attributed to the material characteristics including high purity, fully dense, rough surface composed of pyramid-like grains, and the columnar grain structures

  16. Simple HPLC method for detection of trace ephedrine and pseudoephedrine in high-purity methamphetamine.

    Science.gov (United States)

    Makino, Yukiko

    2012-03-01

    A simple and sensitive HPLC technique was developed for the qualitative determination of ephedrine and pseudoephedrine (ephedrines), used as precursors of clandestine d-methamphetamine hydrochloride of high purity. Good separation of ephedrines from bulk d-methamphetamine was achieved, without any extraction or derivatization procedure on a CAPCELLPACK C18 MGII (250 × 4.6 mm) column. The mobile phase consisted of 50 mM KH2 PO4-acetonitrile (94:6 v/v %) using an isocratic pump system within 20 min for detecting two analytes. One run took about 50 min as it was necessary to wash out overloaded methamphetamine for column conditioning. The analytes were detected by UV absorbance measurement at 210 nm. A sample (20 mg) was simply dissolved in 1 mL of water, and a 50 μL aliquot of the solution was injected into the HPLC. The detection limits for ephedrine and pseudoephedrine in bulk d-methamphetamine were as low as 3 ppm each. This analytical separation technique made it possible to detect ephedrine and/or pseudoephedrine in seven samples of high-purity d-methamphetamine hydrochloride seized in Japan. The presence of trace ephedrines in illicit methamphetamine may strongly indicate a synthetic route via ephedrine in methamphetamine profiling. This method is simple and sensitive, requiring only commonly available equipment, and should be useful for high-purity methamphetamine profiling.

  17. Isotope dilution mass spectrometry of microelectronically relevant heavy metal traces in high-purity cobalt

    International Nuclear Information System (INIS)

    Because cobalt and its silicides are increasingly used in microelectronic devices, an isotope dilution mass spectrometric (IDMS) method has been developed for trace analysis of relevant heavy metals (U, Th, Fe, Zn, Tl, and Cd) in high-purity cobalt. The measurements of the isotope ratios were carried out with a small thermal ionization quadrupole mass spectrometer by producing positive thermal ions in a single- or double-filament ion source. For the trace/matrix separation and the isolation of the different heavy metals, anion-exchange chromatography and an extraction method for iron were applied. The detection limits obtained were (in ng/g): U = 0.007, Th = 0.017, Tl = 0.06, Cd = 1, Zn = 8, and Fe = 11, which demonstrates that the particularly critical radioactive impurities uranium and thorium could be analysed down to the low pg/g range. Three cobalt samples of different purity were analysed with concentrations ranging from about 0.1 ng/g for U and Th in an ultra high-purity material produced for microelectronic purposes, up to about 70 μg/g for Cd in a cobalt sample with declared purity of 99.8%. Because IDMS usually results in accurate analytical results, it can be used in the future for calibration of other methods like glow discharge mass spectrometry, as could be shown by analysing one cobalt sample by both methods. IDMS can also be applied for the production of urgently needed certified standard reference materials in this important field of high technology. (orig.)

  18. High Purity DNA Extraction with a SPE Microfluidic Chip Using KI as the Binding Salt

    Institute of Scientific and Technical Information of China (English)

    Xing CHEN; Da Fu CUI; Chang Chun LIU

    2006-01-01

    Based on solid phase extraction method, a novel silicon-PDMS-glass microchip for high purity DNA extraction has been developed by using KI as the binding salt. The microfluidic chip fabricated by MEMS technology was composed of a silicon substrate with a coiled channel and a compounded PDMS-glass cover. With this microfluidic chip, the wall of the coiled channel was used as solid phase matrix for binding DNA and DNA was extracted by the fluxion of the binding buffer, washing buffer and elution buffer. KI as a substitute for guanidine, was used successfully as binding salt for purification DNA, obtaining higher purity of genomic DNA and about 13.9 ng DNA from 1 μL rat whole blood in 35 minutes.

  19. Construction of a Bacillus amyloliquefaciens strain for high purity levan production.

    Science.gov (United States)

    Feng, Jun; Gu, Yanyan; Han, Lifang; Bi, Kexin; Quan, Yufeng; Yang, Chao; Zhang, Wei; Cao, Mingfeng; Wang, Shufang; Gao, Weixia; Sun, Yang; Song, Cunjiang

    2015-06-01

    Bacillus amyloliquefaciens NK-1 has the potential to produce levan and poly-gamma-glutamic acid (γ-PGA) simultaneously. However, it is not possible to purify each single product from the same strain because the extraction process is identical. We deleted the pgs cluster (for γ-PGA synthesis) from the NK-1 strain and constructed a γ-PGA-deficient NK-ΔLP strain. Nuclear magnetic results showed that the NK-ΔLP strain could produce high purity levan product. However, its levan titer was only 1.96 g L(-1) in the basal medium. Single-factor experimental and response surface methodology was used to optimize the culture condition, leading to levan titer of 13.9 and 22.6 g L(-1) in flask culture and in a 5-L bioreactor, respectively. The levan purity can reach to 92.7% after 48 h cultivation. Furthermore, the relationship between levanase (LevB) and levan molecular weight was studied. The results showed that LevB resulted in the production of low molecular weight levan and its expression level determined the ratio of high and low molecular weight levan. We also deleted the sac cluster (for levan synthesis) from the NK-1 strain and constructed a levan-deficient NK-L strain. The NK-L strain exhibited increased purity of γ-PGA product from 79.5 to 91.2%. PMID:25953857

  20. A prototype High Purity Germanium detector for high resolution gamma-ray spectroscopy at high count rates

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, R.J., E-mail: rjcooper@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Amman, M.; Luke, P.N. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Vetter, K. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Nuclear Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-09-21

    Where energy resolution is paramount, High Purity Germanium (HPGe) detectors continue to provide the optimum solution for gamma-ray detection and spectroscopy. Conventional large-volume HPGe detectors are typically limited to count rates on the order of ten thousand counts per second, however, limiting their effectiveness for high count rate applications. To address this limitation, we have developed a novel prototype HPGe detector designed to be capable of achieving fine energy resolution and high event throughput at count rates in excess of one million counts per second. We report here on the concept, design, and initial performance of the first prototype device.

  1. Formation of High-Purity Indium Oxide Nanoparticles and Their Application to Sensitive Detection of Ammonia

    Directory of Open Access Journals (Sweden)

    Sanjeev K. Bhardwaj

    2015-12-01

    Full Text Available High-purity In2O3 nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These In2O3 nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed sensor offered very quick response time (around 10 s and highly sensitive detection of ammonia (at a detection limit of 1 ppm.

  2. Formation of High-Purity Indium Oxide Nanoparticles and Their Application to Sensitive Detection of Ammonia.

    Science.gov (United States)

    Bhardwaj, Sanjeev K; Bhardwaj, Neha; Kukkar, Manil; Sharma, Amit L; Kim, Ki-Hyun; Deep, Akash

    2015-01-01

    High-purity In₂O₃ nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These In₂O₃ nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed sensor offered very quick response time (around 10 s) and highly sensitive detection of ammonia (at a detection limit of 1 ppm).

  3. Requirements on pumps for supply of high-purity water; Anforderungsprofil an Pumpen fuer die Reinstwasserversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Pfeffer, R. [Philipp Hilge GmbH, Bodenheim (Germany)

    2001-07-01

    In pharmaceutical plants, the quality of high-purity water supply depends to a high degree on the materials, pipe conduit design and control systems, sterilisation characteristics of components like pipelines, armatures and pumps, and the design of the plant components. [German] Eine grosse Rolle fuer die Sicherstellung der Qualitaet einer Pharmaanlage und speziell von Reinstwasseranlagen fuer Wasser fuer Injektionszwecke spielt die Auswahl der Werkstoffe, die Leitungsfuehrung und Regeltechnik, die Sterilisationsfaehigkeit der verwendeten Bauteile wie Rohrleitungen, Armaturen und Pumpen sowie die Konstruktionsmerkmale der Anlagenteile. (orig.)

  4. Recycling of high purity selenium from CIGS solar cell waste materials

    International Nuclear Information System (INIS)

    Highlights: • A new method for recycling of selenium from CIGS solar cell materials is presented. • Separation of selenium as selenium dioxide after heating in oxygen atmosphere. • Complete selenium separation after oxidation of <63 μm particles at 800 °C for 1 h. • After reduction of selenium dioxide the selenium purity was higher than 99.999 wt%. - Abstract: Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition to the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1 h at 800 °C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS

  5. Ion implanted N-type contract for high-purity germanium radiation detectors

    International Nuclear Information System (INIS)

    Thin large-area n+ contacts on high-purity germanium detectors have been produced by implantation of 25 keV phosphorous ions. The contacts show leakage current of less than 10-9 A up to fields of greater than 2000 V/cm. Unannealed lattice damage may still limit the maximum applied field, but proper surface treatment prior to implantation and subsequent annealing steps have resulted in a dramatic improvement in the applied field. Spectra are presented which demonstrate that the n+ window is thin and the spectrometer performance is excellent

  6. Preparation of high-purity bismuth by sulphur deleadization in vacuum distillation

    Institute of Scientific and Technical Information of China (English)

    熊利芝; 何则强; 刘文萍; 麻成金; 戴永年

    2004-01-01

    The feasibility of separation of impurities in refined bismuth and sulphur deleadization with vacuum distillation was studied theoretically. Experimental studies on sulphur deleadization were carried out under vacuum.The influences of amount of sulphur, distillation temperature, vacuum degree and distillation time on deleadization were investigated and an optimal technical condition was achieved. The content of lead in refined bismuth can be decreased from 30 μg/g to 0.21 μg/g, which has reached the level of "5N" high-purity bismuth. Other impurities in refined bismuth can be also removed effectively under certain conditions.

  7. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    International Nuclear Information System (INIS)

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability

  8. High purity H-2/H2O/Ni/SZ electrodes at 500 degrees C

    DEFF Research Database (Denmark)

    Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion;

    2013-01-01

    The performance of SOFC (solid oxide fuel cell) anodes is influenced negatively by impurities. In the present study segregation of impurities is minimized by using high purity materials at relatively low temperatures to prevent fast segregation. Ni point electrodes on polished single crystals...... of stabilized zirconia (SZ) with 10,13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 degrees C in mixtures of H-2/H2O over 46 days. The polarization resistances (R-p) for all samples increased significantly during the first 10-20 days at 500...

  9. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, P. V., E-mail: kpv@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Vlasov, I. V. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Sklyarova, E. A.; Smekalina, T. V. [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability.

  10. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    Science.gov (United States)

    Kuznetsov, P. V.; Vlasov, I. V.; Sklyarova, E. A.; Smekalina, T. V.

    2015-10-01

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability.

  11. GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS OF HIGH PURITY SULFUR HEXAFLUORIDE ENRICHED WITH 32S ISOTOPE

    OpenAIRE

    Krylov, V. A.; Sozin, A. Iu.; Chernova, O. Iu.

    2016-01-01

    The method of gas chromatography-mass spectrometry was used for the first time to investigate the impurity composition of high-purity sulfur hexafluoride enriched with 32S isotope. For the separation of impurities an adsorption capillary column GS-GasPro of 60 m ´ 0.32 mm with a modified silica gel and a column of 25 m × 0.26 mm, df = 0.25 microns with  a poly trimethylsilyl propyne (PTMSP) were used. It was shown that GS-GasPro column allowed separating the impurity substances with low molec...

  12. Search of axions from a nuclear power reactor with a high-purity germanium detector

    International Nuclear Information System (INIS)

    This article reports the first study of possible emissions of axions from power reactors using Primakoff and Compton conversions as the detection mechanisms. The expected experimental signatures are mono-energetic lines produced by their Primakoff or Compton conversions at a high-purity germanium (HPGe) detector. No evidence of axion emissions were observed and constraints on axion couplings versus axion mass within the framework of invisible axion models were placed. This experimental approach provides a unique probe for axion mass at the keV-MeV range not accessible to the other techniques

  13. Electron emission in collisions of fast highly charged bare ions with helium atoms

    Science.gov (United States)

    Mondal, Abhoy; Mandal, Chittranjan; Purkait, Malay

    2016-01-01

    We have studied the electron emission from ground state helium atom in collision with fast bare heavy ions at intermediate and high incident energies. In the present study, we have applied the present three-body formalism of the three Coulomb wave (3C-3B) model and the previously adopted four-body formalism of the three Coulomb wave (3C-4B). To represent the active electron in the helium atom in the 3C-3B model, the initial bound state wavefunction is chosen to be hydrogenic with an effective nuclear charge. The wavefunction for the ejected electron in the exit channel has been approximated to be a Coulomb continuum wavefunction with same effective nuclear charge. Effectively the continuum-continuum correlation effect has been considered in the present investigation. Here we have calculated the energy and angular distribution of double differential cross sections (DDCS) at low and high energy electron emission from helium atom. The large forward-backward asymmetry is observed in the angular distribution which is explained in terms of the two-center effect (TCE). Our theoretical results are compared with available experimental results as well as other theoretical calculations based on the plain wave Born approximation (PWBA), continuum-distorted wave (CDW) approximation, continuum-distorted wave eikonal-initial state (CDW-EIS) approximation, and the corresponding values obtained from the 3C-4B model [S. Jana, R. Samanta, M. Purkait, Phys. Scr. 88, 055301 (2013)] respectively. It is observed that the four-body version of the present investigation produces results which are in better agreement with experimental observations for all cases.

  14. Recycling of high purity selenium from CIGS solar cell waste materials.

    Science.gov (United States)

    Gustafsson, Anna M K; Foreman, Mark R StJ; Ekberg, Christian

    2014-10-01

    Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To make CIGS solar cells more competitive, both economically and environmentally, in comparison to other energy sources, methods for recycling are needed. In addition to the generally high price of the material, significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling selenium from CIGS through oxidation at elevated temperatures was therefore examined. During oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals. After oxidation for 1h at 800°C all of the selenium was separated from the CIGS material. Two different reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that the studied selenium separation method could be the first step in a recycling process aimed at the complete separation and recovery of high purity elements from CIGS.

  15. High purity isotopically enriched 70Ge and 74Ge single crystals: Isotope separation, growth, and properties

    International Nuclear Information System (INIS)

    70Ge and 74Ge isotopes were successfully separated from natural Ge and zone purified. Several highly enriched, high purity 70Ge and 74Ge single crystals were grown by the vertical Bridgman method. The growth system was designed for reliable growth of low dislocation density, high purity Ge single crystals of very small weight (∼4g). A 70Ge and a 74Ge crystal were selected for complete characterization. In spite of the large surface to volume ratio of these ingots, both 70Ge and 74Ge crystals contain low electrically active chemical net-impurity concentrations of ∼2x1012 cm-3, which is two orders of magnitude better than that of 74Ge crystals previously grown by two different groups.1,2 Isotopic enrichment of the 70Ge and the 74Ge crystals is 96.3% and 96.8%, respectively. The residual donors and acceptors present in both crystals were identified as phosphorus and copper, respectively. In addition less than 1011 cm-3 gallium, aluminum, and indium were found in the 70Ge crystal

  16. High purity NaI(Tl) scintillator to search for dark matter

    CERN Document Server

    Fushimi, Ken-Ichi; Hazama, Ryuta; Ikeda, Haruo; Inoue, Kunio; Imagawa, Kyoshiro; Kanzaki, Gakuji; Kozlov, Alexandre; Orito, Reiko; Shima, Tatsushi; Takemoto, Yasuhiro; Teraoka, Yuri; Umehara, Saori; Yoshida, Sei

    2016-01-01

    A high purity and large volume NaI(Tl) scintillator was developed to search for cosmic dark matter. The required densities of radioactive impurities (RIs) such as U-chain, Th-chain are less than a few ppt to establish high sensitivity to dark matter. The impurity of RIs were effectively reduced by selecting raw materials of crucible and by performing chemical reduction of lead ion in NaI raw powder. The impurity of $^{226}$Ra was reduced less than 100 $\\mu$Bq/kg in NaI(Tl) crystal. It should be remarked that the impurity of $^{210}$Pb, which is difficult to reduce, is effectively reduced by chemical processing of NaI raw powder down to less than 30 $\\mu$Bq/kg. The expected sensitivity to cosmic dark matter by using 250 kg of the high purity and large volume NaI(Tl) scintillator (PICO-LON; Pure Inorganic Crystal Observatory for LOw-background Neutr(al)ino) is 7$\\times$10$^{-45}$ cm$^{2}$ for 50 GeV$/c^{2}$ WIMPs.

  17. Device to generate high purity hydroxide solution in-line for ion chromatography.

    Science.gov (United States)

    Masunaga, Hiroto; Higo, Yuji; Ishii, Mizuo; Maruyama, Noboru; Yamazaki, Shigeo

    2016-05-01

    Herein, we report a new device that generates a high-purity hydroxide solution in line. The device's container has three compartments that are isolated from each other by two cation exchange (CE) membranes. In each end of the container, an electrode is installed. The three compartments are filled with ion exchange resins. A bipolar boundary is a composite boundary comprising anion- and cation-exchangers. This device has two bipolar boundaries, which are used to separate the location of hydroxide solution generation from the location where water is electrolyzed. Therefore, it can produce high-purity hydroxide solutions that are free from gases and anionic impurities. The hydroxide solution is generated on the basis of an electrokinetic phenomenon at the surfaces of ion-exchange resins and membranes in an electric field; NaOH concentration can be controlled at rates from 0.01 to 100mM per 1mL/min by adjusting the electrical current (0-200mA) applied to the device. As the generated solution is used as an eluent for a suppressed anion chromatography, the electrical conductivity of the effluent from the suppressor is as low as that of ultra-pure water. Thus, the noise of the base-line electrical conductivity is improved, and so the detection limit of anions on the sub-ng/mL order can be achieved. PMID:27063368

  18. Device to generate high purity hydroxide solution in-line for ion chromatography.

    Science.gov (United States)

    Masunaga, Hiroto; Higo, Yuji; Ishii, Mizuo; Maruyama, Noboru; Yamazaki, Shigeo

    2016-05-01

    Herein, we report a new device that generates a high-purity hydroxide solution in line. The device's container has three compartments that are isolated from each other by two cation exchange (CE) membranes. In each end of the container, an electrode is installed. The three compartments are filled with ion exchange resins. A bipolar boundary is a composite boundary comprising anion- and cation-exchangers. This device has two bipolar boundaries, which are used to separate the location of hydroxide solution generation from the location where water is electrolyzed. Therefore, it can produce high-purity hydroxide solutions that are free from gases and anionic impurities. The hydroxide solution is generated on the basis of an electrokinetic phenomenon at the surfaces of ion-exchange resins and membranes in an electric field; NaOH concentration can be controlled at rates from 0.01 to 100mM per 1mL/min by adjusting the electrical current (0-200mA) applied to the device. As the generated solution is used as an eluent for a suppressed anion chromatography, the electrical conductivity of the effluent from the suppressor is as low as that of ultra-pure water. Thus, the noise of the base-line electrical conductivity is improved, and so the detection limit of anions on the sub-ng/mL order can be achieved.

  19. Recovery of high purity sulfuric acid from the waste acid in toluene nitration process by rectification.

    Science.gov (United States)

    Song, Kai; Meng, Qingqiang; Shu, Fan; Ye, Zhengfang

    2013-01-01

    Waste sulfuric acid is a byproduct generated from numerous industrial chemical processes. It is essential to remove the impurities and recover the sulfuric acid from the waste acid. In this study the rectification method was introduced to recover high purity sulfuric acid from the waste acid generated in toluene nitration process by using rectification column. The waste acid quality before and after rectification were evaluated using UV-Vis spectroscopy, GC/MS, HPLC and other physical and chemical analysis. It was shown that five nitro aromatic compounds in the waste acid were substantially removed and high purity sulfuric acid was also recovered in the rectification process at the same time. The COD was removed by 94% and the chrominance was reduced from 1000° to 1°. The recovered sulfuric acid with the concentration reaching 98.2 wt% had a comparable quality with commercial sulfuric acid and could be recycled back into the toluene nitration process, which could avoid waste of resources and reduce the environmental impact and pollution.

  20. Microwave-assisted co-precipitation synthesis of high purity β-tricalcium phosphate crystalline powders

    International Nuclear Information System (INIS)

    Highlights: → A new fabrication technique has been set up for the preparation of high purity β-TCP. → β-TCP could be obtained in a short time. → The formation process of β-TCP was different from the previous reports. - Abstract: A new fabrication technique of β-tricalcium phosphate (β-TCP) has been investigated by the microwave-assisted co-precipitation method and subsequent calcinations. The synthesized powders were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), thermogravimetry-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The calcium/phosphorous atomic ratio of the as-dried sample was determined by energy dispersive analysis of X-rays (EDAX). The results showed that high purity and well-crystallized β-TCP powders could be obtained in a rapid way by microwave processing. The formation process of β-TCP was explained based on the TG-DTA analysis. The effects of microwave irradiation on the reaction mechanism and reaction rate were preliminarily analyzed in the paper.

  1. Micromechanisms of deformation in high-purity hot-pressed alumina

    Energy Technology Data Exchange (ETDEWEB)

    Staehler, J.M.; Predebon, W.W.; Subhash, G. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Mechanical Engineering and Engineering Mechanics; Pletka, B.J. [Metallurgical and Materials Engineering Dept., Michigan Technological Univ., Houghton, MI (United States)

    2000-10-31

    A high-strength aluminum oxide was produced by vacuum hot pressing high-purity, submicron-size alumina powders. The uniaxial compressive fracture strength was strongly strain-rate sensitive and varied from 5.5 GPa at 10{sup -4} s{sup -1} to 8.3 GPa at 10{sup 3} s{sup -1}. A Hugoniot elastic limit of about 11.9 GPa was determined from flyer plate impact tests. The deformation/fracture process was examined using both uniaxial stress and uniaxial strain conditions. Under a uniaxial stress condition, microplasticity was observed in the form of aligned dislocations that appeared similar to shear bands in metals. Under a uniaxial strain condition, extensive dislocation activity, grain boundary microcracking and occasional twins were observed. Based on the experimental results and microscopic observations, possible mechanisms responsible for the observed high strength and high strain-rate sensitivity in this alumina are discussed. (orig.)

  2. Formation of recrystallization cube texture in high purity face-centered cubic metal sheets

    Energy Technology Data Exchange (ETDEWEB)

    Mao, W.

    1999-10-01

    An investigation on recrystallization textures in high purity face-centered cubic (fcc) aluminum, copper, and nickel indicated that the cube texture is a unique dominant final texture. In a macroview of rolling deformation, a balanced activation of four slip systems can result in certain stability of some substructure with cube orientation in the deformed matrix. In the stable substructure the dislocation density is very low, and the dislocation configuration is rather simple in comparison to other orientations so that the cube substructure can easily be transformed into cube recrystallization nuclei by a recovery process. A high orientation gradient and correspondingly high angle boundaries to the deformed matrix are usually expected around the cube nuclei, which, therefore, grow rapidly. After the primary recrystallization, the size of cube grains is much larger than the grains with other orientations, which will be expensed as the cube grains grow further, so that the cube texture can finally become a dominant texture component.

  3. Germanium field-effect transistor made from a high-purity substrate

    International Nuclear Information System (INIS)

    Field effect transistors have been fabricated on high-purity germanium substrates using low-temperature technology. The aim of this work is to preserve the low density of trapping centers in high-quality starting material by low-temperature (0C) processing. The use of germanium promises to eliminate some of the traps which cause generation-recombination noise in silicon field-effect transistors (FET's) at low temperatures. Typically, the transconductance (g/sub m/) in the germanium FET's is 10 mA/V and the gate leakage can be less than 10-12 A. Present devices exhibit a large 1/f noise component and most of this noise must be eliminated if they are to be competitive with silicon FET's commonly used in high-resolution nuclear spectrometers

  4. A Circularly Symmetric Antenna Design With High Polarization Purity and Low Spillover

    CERN Document Server

    Holler, C M; Jones, M E; King, O G; Muchovej, S J C; Stevenson, M A; Wylde, R J; Copley, C J; Davis, R J; Pearson, T J; Readhead, A C S

    2011-01-01

    We describe the development of two circularly symmetric antennas with high polarization purity and low spillover. Both were designed to be used in an all-sky polarization and intensity survey at 5 GHz (the C-Band All-Sky Survey, C-BASS). The survey requirements call for very low levels of cross-polar leakage and far-out sidelobes. Two different existing antennas, with 6.1-m and 7.6-m diameter primaries, were adapted by replacing the feed and secondary optics, resulting in identical beam performances of 0.73deg FWHM, cross-polarization better than -50 dB, and far-out sidelobes below -70 dB. The polarization purity was realized by using a symmetric low-loss dielectric foam support structure for the secondary mirror, avoiding the need for secondary support struts. Ground spill-over was largely reduced by using absorbing baffles around the primary and secondary mirrors, and by the use of a low-sidelobe profiled corrugated feedhorn. The 6.1-m antenna and receiver have been completed and test results show that the ...

  5. High-quality and high-purity homoepitaxial diamond (100) film growth under high oxygen concentration condition

    International Nuclear Information System (INIS)

    Defect formation during diamond homoepitaxial growth was sufficiently inhibited by adding oxygen simultaneously in the growth ambient with high concentration of 2%. A 30-μm thick diamond films with surface roughness of <2 nm were homoepitaxially deposited on the (100) diamond single crystal substrates with reasonable growth rate of approximately 3 μm h−1 under the conditions of higher methane concentration of 10%, higher substrate temperature of ∼1000 °C, and higher microwave power density condition of >100 W cm−3. Surface characteristic patterns moved to an identical direction with growth thickness, indicating that lateral growth was dominant growth mode. High chemical purity represented by low nitrogen concentration of less than 1 ppb and the highest 12C isotopic ratio of 99.998% of the obtained homoepitaxial diamond (100) films suggest that the proposed growth condition has high ability of impurity control

  6. Hot working of high purity Fe-C alloys in the {alpha}-range

    Energy Technology Data Exchange (ETDEWEB)

    Montheillet, F; Le Coze, J, E-mail: montheil@emse.f [Ecole des Mines (SMS), CNRS UMR 5146, 158 cours Fauriel, 42023 Saint-Etienne Cedex 2 (France)

    2010-07-01

    The influence of carbon in solid solution on the stress-strain curves of {alpha}-iron was investigated using model alloys prepared from high purity iron. Uniaxial compression tests were carried out within the ferritic domain at temperatures between 700 and 880 {sup 0}C. Oscillating stress-strain curves observed at high temperatures and low strain rates indicate that discontinuous dynamic recrystallization takes place. The macroscopic strain rate sensitivities m and apparent activation energies Q associated with the flow stress are not significantly modified by carbon additions. By contrast, the 'mesoscopic' parameters h and r associated with strain hardening and dynamic recovery, respectively, are strongly dependent on the carbon content. Finally, an estimation of the grain boundary mobilities during dynamic recrystallization was carried out from the above rheological data.

  7. Status of Research on Application of High Purity Rare Earth Oxides in Solid Oxide Fuel Cells

    Institute of Scientific and Technical Information of China (English)

    Ma Zhihong; Qiu Jufeng

    2004-01-01

    The solid oxide fuel cell (SOFC) is a high-efficient and environmentally friendly power generation system.The rare earth oxide materials are used extensively in the manufacturing of SOFC components.In particular, the CeO2doped with Gd2O3 or Sm2O3, lanthanide perovskite oxides are indispensable and key materials for developing the intermediate temperature SOFC.The research and development status of application of high purity rare earth oxides in SOFC was overviewed.The rare earth oxide-based and -doped materials were discussed for the SOFC components.Concerning the rare earth oxides applicable to SOFC, several topics were also pointed out for further researching and developing.

  8. The influence of grain size and texture on the mechanical response of high purity hafnium

    International Nuclear Information System (INIS)

    The mechanical behavior of hafnium is influenced by texture, strain rate, temperature, chemistry, and stress state; however the effects of microstructure remain poorly understood. As is observed in other group IVb elements, such as titanium and zirconium, deformation in hafnium at quasi-static and dynamic strain rates occurs through a combination of prismatic slip, pyramidal slip, and twinning. For titanium and zirconium, the mechanical behavior has been previously shown to be highly dependent upon the average grain size of the material. Here, the effects of grain size on the mechanical response of high purity hafnium tested in compression are systematically probed and the flow stress and work hardening behavior is correlated with the substructural and textural evolution during deformation. The influence of strain rate, temperature, and texture as a function of the microstructure is examined and Hall-Petch constants for hafnium are calculated

  9. Observation of Impact Ionization of Shallow States in Sub-Kelvin, High-Purity Germanium

    Science.gov (United States)

    Phipps, A.; Sadoulet, B.; Sundqvist, K. M.

    2016-07-01

    We report on the observation of impact ionization processes involving shallow impurity states in a sub-Kelvin, high-purity n-type germanium detector similar to those used by direct detection dark matter experiments such as the Cryogenic Dark Matter Search. An optical fiber is used to generate packets of charge carriers near one surface of the detector. The charge carriers drift to the opposite surface by application of an electric field. The resulting drift current is measured by a high-speed charge amplifier. The onset of impact ionization for both electron and hole transport is clearly observed in the drift current as the applied electric field is increased above ≈ 5 V/cm. We present the effective charge collection efficiency and trapping length as a function of applied electric field for electrons and holes. We estimate the impact ionization cross section to be on the order of 5× 10^{-13} mathrm {cm}^2.

  10. A Rapid and Cost-Effective Laser Based Synthesis of High Purity Cadmium Selenide Quantum Dots.

    Science.gov (United States)

    Gondall, M A; Qahtan, Talal F; Dastageer, M A; Yamani, Z H; Anjum, D H

    2016-01-01

    A rapid and cost effective method is developed to synthesize high purity cadmium Selenide (CdSe) quantum dots in acetone medium using second harmonic of Nd:YAG nanosecond pulsed laser of 532 nm wavelength. The thermal agglomeration due the nanosecond pulse duration of the laser was successfully eliminated by using unfocussed laser beam and thereby providing a favorable conditions for the synthesis of quantum dots having the grain size of 3 nm. The morphological and optical characterizations like XRD, HRTEM, optical absorption of the synthesized CdSe quantum dots, reveal that the material possesses the similar characteristics of the one synthesized through cumbersome wet chemical methods. Relative to the CdSe bulk material, the synthesized CdSe quantum dots showed a blue shift in the measured band gap energy from near infrared spectral region to visible region, making this material very attractive for many solar energy harvesting applications like photo-catalysis and solar cells. PMID:27398538

  11. All-fibre multiplexed source of high-purity heralded single photons

    CERN Document Server

    Francis-Jones, Robert J A; Mosley, Peter J

    2016-01-01

    Single photon sources based on spontaneous photon-pair generation have enabled pioneering experiments in quantum optics. However, their non-determinism presents a bottleneck to scaling up photonic and hybrid quantum-enhanced technologies. Furthermore, photon pairs are typically emitted into many correlated frequency modes, producing an undesirable mixed state on heralding. Here we present a complete fibre-integrated heralded single photon source that addresses both these difficulties simultaneously. We use active switching to provide a path to deterministic operation by multiplexing separate spontaneous sources, and dispersion engineering to minimise frequency correlation for high-purity single photon generation. All the essential elements -- nonlinear material with dispersion control, wavelength isolation, optical delay, and fast switching -- are incorporated in a low-loss alignment-free package that heralds photons in telecoms single-mode fibre. Our results demonstrate a scalable approach to delivering pure...

  12. Estimation of decrease in efficiency of the high purity Germanium detector after a long time operation

    International Nuclear Information System (INIS)

    In many recent years, the gamma spectrometry using the high purity germanium (HPGe) detector have come into widespread use to determine the activity of radioactive samples. However, the decrease in detector efficiency remarkably influences on the result of measured gamma spectra. In this work, we estimated the decrease in efficiency of the GC1518 HPGe detector made in Canberra Industries, Inc. and located at the Center for HCMC Nuclear Techniques. It was found that the detector efficiency reduces to 8% within 6 years from October 1999 to August 2005. The decrease in efficiency can be explained by increase in the thickness of an inactive germanium layer based on using the Monte Carlo simulation. (author)

  13. Simulation for photon detection in spectrometric system of high purity (HPGe) using MCNPX code

    International Nuclear Information System (INIS)

    The Brazilian National Commission of Nuclear Energy defines parameters for classification and management of radioactive waste in accordance with the activity of materials. The efficiency of a detection system is crucial to determine the real activity of a radioactive source. When it's possible, the system's calibration should be performed using a standard source. Unfortunately, there are only a few cases that it can be done this way, considering the difficulty of obtaining appropriate standard sources for each type of measurement. So, computer simulations can be performed to assist in calculating of the efficiency of the system and, consequently, also auxiliary the classification of radioactive waste. This study aims to model a high purity germanium (HPGe) detector with MCNPX code, approaching the spectral values computationally obtained of the values experimentally obtained for the photopeak of 137Cs. The approach will be made through changes in outer dead layer of the germanium crystal modeled. (author)

  14. Influence of carbon and nitrogen on corrosion resistance of high purity Fe-50mass% Cr alloys

    International Nuclear Information System (INIS)

    High purity Fe-50mass%Cr alloys containing (C+N) in the range of 30 to 500 mass ppm were prepared and their corrosion resistance was investigated. Pitting potential in a 3.5mass%NaCl solution at 343K rose with reducing (C+N) content. Alloys containing (C+N) at less than 100 mass ppm did not sustain pitting corrosion. However, alloys containing 500 mass ppm (C+N) corroded severely in 6%FeCl3+1/20N HCl solutions. Heat treatment at 923K was recognized as influencing corrosion resistance due to precipitation of carbonitrides only in the case of the alloy containing 500 mass ppm (C+N). (orig.)

  15. Defects interaction processes in deformed high purity polycrystalline molybdenum at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lambri, O.A., E-mail: olambri@fceia.unr.edu.ar [Laboratorio de Materiales, Escuela de Ingeniería Eléctrica, Centro de Tecnología e Investigación Eléctrica, Facultad de Ciencias Exactas, Ingeniería y Agrimensura, Universidad Nacional de Rosario – CONICET, Avda. Pellegrini 250, (2000) Rosario (Argentina); Bonifacich, F.G. [Laboratorio de Materiales, Escuela de Ingeniería Eléctrica, Centro de Tecnología e Investigación Eléctrica, Facultad de Ciencias Exactas, Ingeniería y Agrimensura, Universidad Nacional de Rosario – CONICET, Avda. Pellegrini 250, (2000) Rosario (Argentina); Bozzano, P.B. [Laboratorio de Microscopía Electrónica, Unidad de Actividad Materiales, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica e Instituto Sábato – Universidad Nacional de San Martín, Avda. Gral. Paz 1499, (1650) San Martín (Argentina); Zelada, G.I. [Laboratorio de Materiales, Escuela de Ingeniería Eléctrica, Centro de Tecnología e Investigación Eléctrica, Facultad de Ciencias Exactas, Ingeniería y Agrimensura, Universidad Nacional de Rosario – CONICET, Avda. Pellegrini 250, (2000) Rosario (Argentina); and others

    2014-10-15

    Mechanical spectroscopy (damping and elastic modulus as a function of temperature) and transmission electron microscopy studies have been performed in high purity polycrystalline molybdenum plastically deformed to different values of tensile and torsion strain. Mechanical spectroscopy measurements were performed from room temperature up to 1285 K. A relaxation peak in polycrystalline molybdenum related to the movement of dislocations into lower energy configurations near grain boundaries has been discovered to appear around 1170 K. The activation energy of the peak is 4.2 eV ± 0.5 eV. This relaxation phenomenon involves the interaction between vacancies and mobile dislocations near the grain boundaries. It should be highlighted that this relaxation process is controlled by the arrangement of vacancies and dislocations which occur at temperature below 1070 K.

  16. High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

    Directory of Open Access Journals (Sweden)

    Han Chulwoong

    2015-06-01

    Full Text Available Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungsten carbide-cobalt hard metal scrap was mechanically broken into particles and then tungsten trioxide particle was recovered by hydrometallurgical method. Recovered tungsten trioxide was reduced to tungsten particle in a hydrogen environment. After that, tungsten particle was melted and solidified to make a spherical one by RF (Ratio Frequency thermal plasma process. Well spherical tungsten micro-particle was successfully obtained from spent scrap. In addition to the morphological change, thermal plasma process showed an advantage for the purification of feedstock particle.

  17. A simple high-sensitivity technique for purity analysis of xenon gas

    CERN Document Server

    Leonard, D S; Hall, C; Kaufman, L; Langford, T; Slutsky, S; Yen, Y R

    2010-01-01

    We report on the development and performance of a high-sensitivity purity-analysis technique for gaseous xenon. The gas is sampled at macroscopic pressure from the system of interest using a UHV leak valve. The xenon present in the sample is removed with a liquid-nitrogen cold trap, and the remaining impurities are observed with a standard vacuum mass-spectroscopy device. Using calibrated samples of xenon gas spiked with known levels of impurities, we find that the minimum detectable levels of N2, O2, and methane are 1 ppb, 160 ppt, and 60 ppt respectively. This represents an improvement of about a factor of 10,000 compared to measurements performed without a coldtrap.

  18. Effect of hot finishing rolling on cube texture in high purity aluminum foils

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of hot finishing rolling temperature on cube texture in high purity aluminium foils was investigated by means of orientation distribution functions (ODFs). The results show that a relatively strong rotated cube orientation {100}〈011〉 exists when the end temperature of hot finishing rolling is 290  ℃, and the cube texture is the strongest after the final recrystallization. The cold rolling textures are comprised of S?-, Cu- and Bs-components, and the orientation {100}〈011〉 is unstable, it may be split and evolved into two complementary copper components (112) [1—1—1] and (1—1—2) [111] during the cold rolling. And a sharp cube recrystallization texture would nucleate and grow in the deformation matrix with the Cu-orientation.

  19. Application of Thermodynamic Calculations to the Pyro-refining Process for Production of High Purity Bismuth

    Science.gov (United States)

    Mezbahul-Islam, Mohammad; Belanger, Frederic; Chartrand, Patrice; Jung, In-Ho; Coursol, Pascal

    2016-04-01

    The present work has been performed with the aim to optimize the existing process for the production of high purity bismuth (99.999 pct). A thermo-chemical database including most of the probable impurities of bismuth (Bi-X, X = Ag, Au, Al, Ca, Cu, Fe, Mg, Mn, Na, Ni, Pb, S, Sb, Sn, Si, Te, Zn) has been constructed to perform different thermodynamic calculations required for the refining process. Thermodynamic description for eight of the selected binaries, Bi-Ca, Cu, Mn, Ni, Pb, S, Sb, and Sn, has been given in the current paper. Using the current database, different thermodynamic calculations have been performed to explain the steps involved in the bismuth refining process.

  20. Synthesis of Magnetite Nanoparticles by Top-Down Approach from a High Purity Ore

    Directory of Open Access Journals (Sweden)

    Gayan Priyadarshana

    2015-01-01

    Full Text Available This study attempts to synthesize magnetite nanoparticles from a high purity natural iron oxide ore found in Panvila, Sri Lanka, following a novel top-down approach. Powder X-Ray diffraction, elemental analysis, and chemical analysis data confirmed the ore to be exclusively magnetite with Fe2+ : Fe3+ ratio of 1 : 2. Surface modified magnetite nanoparticles were synthesized by destructuring of this ore using a top-down approach in the presence of oleic acid. These oleic acid coated nanoparticles were further dispersed in ethanol resulting in stable nanomagnetite dispersion. Interestingly, the nanoparticles demonstrated a spherical morphology with a particle size ranging from 20 to 50 nm. Magnetic force microscopic data was used to confirm the topography of the nanoparticles and to study the magnetic domain structure.

  1. Operation of a high purity germanium crystal in liquid argon as a Compton suppressed radiation spectrometer

    CERN Document Server

    Orrell, J L; Amsbaugh, J F; Doe, P J; Hossbach, T W; Orrell, John L.; Aalseth, Craig E.; Amsbaugh, John F.; Doe, Peter J.; Hossbach, Todd W.

    2007-01-01

    A high purity germanium crystal was operated in liquid argon as a Compton suppressed radiation spectrometer. Spectroscopic quality resolution of less than 1% of the full-width half maximum of full energy deposition peaks was demonstrated. The construction of the small apparatus used to obtain these results is reported. The design concept is to use the liquid argon bath to both cool the germanium crystal to operating temperatures and act as a scintillating veto. The scintillation light from the liquid argon can veto cosmic-rays, external primordial radiation, and gamma radiation that does not fully deposit within the germanium crystal. This technique was investigated for its potential impact on ultra-low background gamma-ray spectroscopy. This work is based on a concept initially developed for future germanium-based neutrinoless double-beta decay experiments.

  2. Assessment of radiochemical purity of [{sup 18}F]fludeoxyglucose by high pressure liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Aline E.; Silva, Juliana B.; Silveira, Marina B.; Ferreira, Soraya Z., E-mail: radiofarmacoscdtn@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

    2011-07-01

    The quality control of [{sup 18}F]fludeoxyglucose ({sup 18}FDG) has received attention due to its increasing clinical use. Although the quality requirements of {sup 18}FDG are established in various pharmacopoeia, the suitability of all testing methods used should be verified under actual conditions of use and documented. The aim of this study was to develop a high pressure liquid chromatography (HPLC) method for radiochemical purity evaluation of {sup 18}FDG, based on pharmacopoeia references, and to verify its suitability for routine quality control in our centre. HPLC analysis was performed with an Agilent HPLC. {sup 18}FDG and impurities were separated on an anion-exchange column by isocratic elution with 0.1 M NaOH as the mobile phase. Detection was accomplished with refractive index and NaI (Tl) scintillation detectors. The flow rate of the mobile phase was set at 0.8 mL/min and the column temperature was kept at 35 deg C. Specificity, linearity, precision and robustness were assessed to verify if the method was adequate for its intended purpose. Retention time of {sup 18}FDG was not affected by the presence of other components of the formulation and a good peak resolution was achieved. The analytical curve of {sup 18}FDG was linear, with a correlation coefficient value of 0.9995. Intraday repeatable precision, reported as the relative standard deviation, was 0.11%. Analytical procedure remained unaffected by small variations in mobile phase flow rate. Results evidenced that HPLC is suitable for radiochemical purity evaluation of {sup 18}FDG, considering operational conditions of our laboratory. (author)

  3. High-purity 3D nano-objects grown by focused-electron-beam induced deposition.

    Science.gov (United States)

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ∼50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core-shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices. PMID:27454835

  4. High-purity 3D nano-objects grown by focused-electron-beam induced deposition

    Science.gov (United States)

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M.; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ˜50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core-shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices.

  5. High-purity 3D nano-objects grown by focused-electron-beam induced deposition

    Science.gov (United States)

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M.; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ∼50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core–shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices.

  6. Qualification and initial characterization of a high-purity 233U spike for use in uranium analyses

    International Nuclear Information System (INIS)

    Several high-purity 233U items potentially useful as isotope dilution mass spectrometry standards for safeguards, non-proliferation, and nuclear forensics measurements are identified and rescued from downblending. By preserving the supply of 233U materials of different pedigree for use as source materials for certified reference materials (CRMs), it is ensured that the safeguards community has high quality uranium isotopic standards required for calibration of the analytical instruments. One of the items identified as a source material for a high-purity CRM is characterized for the uranium isotope-amount ratios using thermal ionization mass spectrometry (TIMS). Additional verification measurements on this material using quadrupole inductively coupled plasma mass spectrometry (ICPMS) are also performed. As a result, the comparison of the ICPMS uranium isotope-amount ratios with the TIMS data, with much smaller uncertainties, validated the ICPMS measurement practices. ICPMS is proposed for the initial screening of the purity of items in the rescue campaign

  7. Simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides by second order derivative spectrophotometry

    International Nuclear Information System (INIS)

    High purity individual rare earth oxides are increasingly used as major components in lasers (Y2O3), phosphors (YVO3, Eu2O3), magnetic bubble memory films (Gd2O3) and refractive-index lenses and fibre optics (La2O3). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper reports the utilization of higher order derivative spectrophotometry for the simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth. (author). 9 refs, 2 figs, 2 tabs

  8. An Inexpensive Route to Synthesize High-Purity CrO2 for EMI Shielding in X-Band Frequencies

    OpenAIRE

    Vivek Verma; Shahab Ahmad; Abdullah Dar; Kotnala, R.

    2012-01-01

    Rod-shaped high-purity samples of CrO2 have been synthesized by an inexpensive and simplified procedure. Here, we have prepared pure CrO2 without applying any external pressure or control it during synthesis. The sample prepared exhibited an improvement in saturation magnetization values, 68 emu/g at 300 K, 136 emu/g at 80 K, and uniform grained microstructure. The complex permittivity, permeability, and microwave absorption properties of high-purity CrO2 sample were investigated in the 8.2–1...

  9. Influence of gas atmospheres on the first-stage sintering of high-purity niobium powders

    International Nuclear Information System (INIS)

    Niobium and tantalum surfaces easily absorb oxygen. With decreasing particle size, the content of oxygen increases. The role of this surface oxygen and oxygen in the sintering atmospheres on the first-stage sintering is not well established. Therefore the sintering behavior of high-purity niobium powders was studied by annealing cylindrical powder compacts (particle size less than 63 microns) in the temperature range from 1000 C to 1600 C in ultra-high vacuum and under low oxygen partial pressures, as well as in inert gas atmospheres with low oxygen contents. The specific surface of the samples was determined by metallographic methods, adsorption, and capacitance measurements. Low oxygen partial pressures (0.0001 Pa) lead to a slight enhancement of the surface diffusion which is controlling first-stage sintering. High heating rates (T greater than 3000 K/min) to temperatures above the melting point of Nb2O5 (Tm 1495 C) enhances the neck growth due to the formation of a liquid oxide phase on the surface of the powder particles. 23 references

  10. Production of Ultrafine, High-purity Ceramic Powders Using the US Bureau of Mines Developed Turbomill

    Science.gov (United States)

    Hoyer, Jesse L.

    1993-01-01

    Turbomilling, an innovative grinding technology developed by the U.S. Bureau of Mines in the early 1960's for delaminating filler-grade kaolinitic clays, has been expanded into the areas of particle size reduction, material mixing, and process reaction kinetics. The turbomill, originally called an attrition grinder, has been used for particle size reduction of many minerals, including natural and synthetic mica, pyrophyllite, talc, and marble. In recent years, an all-polymer version of the turbomill has been used to produce ultrafine, high-purity, advanced ceramic powders such as SiC, Si3N4, TiB2, and ZrO2. In addition to particle size reduction, the turbomill has been used to produce intimate mixtures of high surface area powders and whiskers. Raw materials, TiN, AlN, and Al2O3, used to produce a titanium nitride/aluminum oxynitride (TiN/AlON) composite, were mixed in the turbomill, resulting in strength increases over samples prepared by dry ball milling. Using the turbomill as a leach vessel, it was found that 90.4 pct of the copper was extracted from the chalcopyrite during a 4-hour leach test in ferric sulfate versus conventional processing which involves either roasting of the ore for Cu recovery or leaching of the ore for several days.

  11. Hydrogen in-situ refining method for preparing high purity gadolinium

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guoling [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Li [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Fu, Kai [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Wang, Chongyun [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Zheng, Jie [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Xu, Li [State Grid Smart Grid Research Institute, Future Science& Technology Park, Changping, Beijing 102211 (China); Tian, Wenhuai [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Xingguo, E-mail: xgli@pku.edu.cn [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2015-11-05

    The removal of non-metallic impurities, especially oxygen and nitrogen, from the rare-earth metal gadolinium (Gd) is challenging, due to their strong affinity to Gd metal. Herein we present an effective approach to prepare high purity Gd via a novel hydrogen in-situ refining method. The final concentrations of oxygen and nitrogen could be reduced to 30 and 19 mass ppm, respectively. The changes of lattice parameters were derived from XRD; enthalpy values and gaseous speciation associated with the gas–solid physiochemical reactions were determined through a combination of DSC/MS measurements and thermodynamic calculations. The results show that oxygen and nitrogen can be efficiently removed by degassing Gd with dissolved hydrogen. The underlying mechanism for the refinement is discussed systematically in this paper. - Highlights: • Hydrogen can shuttle gadolinium freely at high temperature. • The concentration of O and N dropped to 30 ppm and 19 ppm, respectively. • The hydrogen content could finally decrease to 17 ppm. • Hydrogen, water and ammonia signals can be detected successfully. • This method is environment friendly and no other recontaminations.

  12. Simultaneously Recovering High-Purity Chromium and Removing Organic Pollutants from Tannery Effluent

    Directory of Open Access Journals (Sweden)

    Jie Zong

    2016-01-01

    Full Text Available Chromium pollution is a serious issue because of carcinogenic toxicities of the pollutants and low recovery rate of chromium because of the presence of organic, such as protein and fat. In this work, high recovery rate and high purity of the chromium ion were successfully prepared by the way of acid enzyme, flocculant, and Fenton oxidation. The experiments were characterized by TG, TOC, UV-VIS, and SEM. In the work, the tannery waste chrome liquor was used as experimental material. The results showed that the percentage of reduction of TOC in the tannery waste chrome liquor by method of Fenton oxidation, acid enzyme, and the flocculant was 71.15%, 65.26%, and 22.05%, respectively. Therefore, the organism content of chrome tanning waste liquid was greatly reduced through the pretreatment. And the application experiment showed that the properties and grain surface and fibers of the tanned leather with commercial chromium powder and chrome tanning agent prepared from the chromium waste liquid treated with Fenton are nearly the same.

  13. Influence of Ta Content in High Purity Niobium on Cavity Performance Preliminary Results*

    CERN Document Server

    Kneisel, P

    2004-01-01

    In a previous paper* a program designed to study the influence of the residual tantalum content on the superconducting properties of pure niobium metal for RF cavities was outlined. The main rationale for this program was based on a potential cost reduction for high purity niobium, if a less strict limit on the chemical specification for Ta content, which is not significantly affecting the RRR–value, could be tolerated for high performance cavities. Four ingots with different Ta contents have been melted and transformed into sheets. In each manufacturing step the quality of the material has been monitored by employing chemical analysis, neutron activation analysis, thermal conductivity measurements and evaluation of the mechanical properties. The niobium sheets have been scanned for defects by an eddy current device. From three of the four ingots—Ta contents 100, 600 and 1,200 wppm—two single cell cavities each of the CEBAF variety have been fabricated and a series of tests on each ...

  14. Evaluation of Electric Load Following Capability on Fuel Cell System Fueled by High-Purity Hydrogen

    Science.gov (United States)

    Doi, Yusuke; Park, Deaheum; Ishida, Masayoshi; Fujisawa, Akitoshi; Miura, Shinichi

    This paper describes the electrical response in load change concerning a fuel cell system fueled by high-purity hydrogen. The purpose of this study is that the fuel cell system is applied to make up for unstable electrical output of a photovoltaic system as a renewable energy. As an alternative method of secondary battery, the fuel cell system, which is able to continuously generate power as long as fuel is supplied, is expected to provide power with high reliability and stability. To evaluate the load-following capability of a polymer electrolyte fuel cell (PEFC) system, an experimental equipment was constructed with a 200W PEFC stack (number of cells: 20, cell area: 200cm2) which was supplied with hydrogen from a compressed hydrogen cylinder and a metal hydride canister. We measured the transient phenomenon of current and cell voltage when the PEFC stack was inputted step-up current loads that changed in the range of 0∼300mA/cm2. As a result, we have found that the PEFC system with both hydrogen supply sources is able to response at a time constant of 6.6∼11.6μsec under enough oxygen supply and a load below the PEFC rated power.

  15. High-Purity Germanium Spectroscopy at Rates in Excess of 10^{6} Events/s

    Energy Technology Data Exchange (ETDEWEB)

    VanDevender, Brent A.; Dion, Michael P.; Fast, James E.; Rodriguez, Douglas C.; Taubman, Matthew S.; Wilen, Christopher D.; Wood, Lynn S.; Wright, Michael E.

    2014-10-01

    Abstract—In gamma spectroscopy, a compromise must be made between energy resolution and event-rate capability. Some foreseen nuclear material safeguards applications require a spectrometer with energy resolution typical of high purity germanium (HPGe) detectors, operated at rates up to and exceeding 106 events per second. We report the performance of an HPGe spectrometer adapted to run at such rates. Our system consists of a commercial semi-coaxial HPGe detector, a modified high-voltagerail, resistive-feedback, charge-sensitive preamplifier and a continuous waveform digitizer. Digitized waveforms are analyzed offline with a novel time-variant trapezoidal filter algorithm. Several time-invariant trapezoidal filters are run in parallel and the slowest one not rejected by instantaneous pileup conditions is used to measure each pulse height. We have attained full-widthat- half-maximum energy resolution of less than 8 keV measured at 662 keV with 1:08*106 per second incoming event rate and 38% throughput. An additional constraint on the width of the fast trigger filter removes a significant amount of edge pileup that passes the first pileup cut, reducing throughput to 26%. While better resolution has been reported by other authors, our throughput is over an order of magnitude higher than any other reported HPGe system operated at such an event rate.

  16. Determination of halogens and sulfur in high-purity polyimide by IC after digestion by MIC.

    Science.gov (United States)

    Krzyzaniak, Sindy R; Santos, Rafael F; Dalla Nora, Flavia M; Cruz, Sandra M; Flores, Erico M M; Mello, Paola A

    2016-09-01

    In this work, a method for sample preparation of high-purity polyimide was proposed for halogens and sulfur determination by ion chromatography (IC) with conductivity detection and, alternatively, by inductively coupled plasma mass spectrometry (ICP-MS). A relatively high polyimide mass (600mg) was completely digested by microwave-induced combustion (MIC) using 20bar of O2 and 50mmolL(-1) NH4OH as absorbing solution. These conditions allowed final solutions with low carbon content (<10mgL(-1)) and suitable pH for analysis by both IC and ICP-MS. The accuracy was evaluated using a certified reference material of polymer for Cl, Br and S and spike recovery experiments for all analytes. No statistical difference (t-test, 95% of confidence level) was observed between the results obtained for Cl, Br and S by IC after MIC and the certified values. In addition, spike recoveries obtained for F, Cl, Br, I and S ranged from 94% to 101%. The proposed method was suitable for polyimide decomposition for further determination of halogens and sulfur by IC and by ICP-MS (Br and I only). Taking into account the lack of methods and the difficulty of bringing this material into solution, MIC can be considered as a suitable alternative for the decomposition of polyimide for routine quality control of halogens and sulfur using IC or ICP-MS. PMID:27343595

  17. Generation of high spectral purity photon-pairs with MgO-doped periodically poled lithium niobate

    Science.gov (United States)

    Zhan, Mengying; Sun, Qichao; Xiang, Tong; Chen, Xianfeng

    2015-12-01

    We study the spectral correlation of photon pairs generated via type-II spontaneous parametric down conversion in periodically poled lithium niobate crystals. By performing Schmidt decomposition on the two-photon wavefunction, we calculate the spectral purity of the two-photon state under various pump laser characteristics and doping concentrations of MgO in lithium niobate crystals. Our results show that periodically poled 5% MgO doped lithium niobate is a good candidate to generate photon-pairs with high spectral purity at telecom wavelength.

  18. Quantification of trace amounts of impurities in high purity cobalt by high resolution inductively coupled plasma mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    XIE Hualin; HUANG Kelong; NIE Xidu; TANG Yougen

    2007-01-01

    An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 24 elements (Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn,Sb, Ba, Pt, Au, and Pb) in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects because of the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 μg.g-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.

  19. Quantification of Trace Amounts of Impurities in High Purity Cobalt by High Resolution Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Hua Lin XIE; Xi Du NIE; You Gen TANG

    2006-01-01

    An analytical method using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au and Pb in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects due to thc presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination was tested and discussed. Correction for matrix effects, Sc, Rh and Bi were used as internal standards. The detection limits is 0.003-0.57 μg/g, the recovery ratio is 92.2%- 111.2%, and the RSD is less than 3.6%. The method is accurate, quick and convenient. It has been applied to the determination of trace impurities in high purity cobalt with satisfactory results.

  20. Effect of grain boundaries on the conductivity of high-purity ZrO2---Y2O3 ceramics

    NARCIS (Netherlands)

    Verkerk, M.J.; Middelhuis, B.J.; Burggraaf, A.J.

    1982-01-01

    Grain boundary conductivities are determined by complex impedance measurements (1–106 Hz) on high-purity ceramics prepared by the alkoxide synthesis and on less pure ceramics obtained from a commercial powder. The grain size was varied systematically in the region 0.36–55 μm. The grain boundary cond

  1. Synthesis of High Purity SiC Powder for High-resistivity SiC Single Crystals Growth

    Institute of Scientific and Technical Information of China (English)

    Li WANG; Xiaobu HU; Xiangang XU; Shouzheng JIANG; Lina NING; Minhua JIANG

    2007-01-01

    High purity silicon carbide (SiC) powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC.Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.

  2. GELATIO: a general framework for modular digital analysis of high-purity Ge detector signals

    Science.gov (United States)

    Agostini, M.; Pandola, L.; Zavarise, P.; Volynets, O.

    2011-08-01

    GELATIO is a new software framework for advanced data analysis and digital signal processing developed for the GERDA neutrinoless double beta decay experiment. The framework is tailored to handle the full analysis flow of signals recorded by high purity Ge detectors and photo-multipliers from the veto counters. It is designed to support a multi-channel modular and flexible analysis, widely customizable by the user either via human-readable initialization files or via a graphical interface. The framework organizes the data into a multi-level structure, from the raw data up to the condensed analysis parameters, and includes tools and utilities to handle the data stream between the different levels. GELATIO is implemented in C++. It relies upon ROOT and its extension TAM, which provides compatibility with PROOF, enabling the software to run in parallel on clusters of computers or many-core machines. It was tested on different platforms and benchmarked in several GERDA-related applications. A stable version is presently available for the GERDA Collaboration and it is used to provide the reference analysis of the experiment data.

  3. Mechanism of strengthening of cube texture for high purity aluminum foils by additional-annealing

    Institute of Scientific and Technical Information of China (English)

    张新明; 刘胜胆; 唐建国; 周卓平

    2003-01-01

    The mechanism of strengthening of cube texture ({001}〈100〉) by additional-annealing of high purity aluminum foils was investigated by using orientation distribution functions (ODFs) and electron back scattered diffraction (EBSD). The results of ODFs and fiber show that the orientation densities of the S {123}〈634〉 and Cu {112}〈111〉 components increase in both the additional-annealed samples and the 0.11 mm final cold-rolled foils. And the EBSD results demonstrate that cube nuclei can be identified in the deformed matrix of those additional-annealed samples. It is suggested that the strengthening of cube texture can be brought out by the increasing of components of S and Cu and the formation of cube nuclei caused by additional-annealing. Moreover, it is found that the cube texture increases first and then decreases with increasing additional-annealing temperature, and it is the strongest at 180 ℃.The strengthening of cube texture by additional-annealing is proposed as the result of oriented growth of cube subgrains.

  4. Synthesis and Characterization of High-purity Aluminum Titanate with Water Quenching Method

    Institute of Scientific and Technical Information of China (English)

    SHEN Yang; RUAN Yu-Zhong; YU Yan

    2009-01-01

    High-purity aluminum titanate was synthesized via a water quenching method with waste-residue in the aluminum factory and industrial TiO2 as the main raw materials, which belongs to the comprehensive utilization of solid wastes. Compared with the conventional method, it can reduce synthesis temperature, effectively inhibit decomposition and raise the content of AT; the addition of tiny silicon powder can improve the sintering and optimize the properties of AT. The crystalline phase structure and microstructure of each sample were characterized with XRD and SEM methods; the content of each crystalline phase in each sample was confirmed with Rietveld Quantification method; the properties of each sample were also tested. The experimental results showed that No. 4 is the optimum specimen, with the corresponding mass ratio of Al2O3/TiO2 to be 1.27 and the content of AT of 97.2 wt%. The addition of optimum tiny silicon powder is confirmed to be 8wt%; its corresponding bulk density is 2.63 g/cm3, bending strength is 46.34 MPa, and the retention of one thermal vibration bending strength is 71.5%.

  5. Stress corrosion of very high purity stainless steels in alkaline media

    International Nuclear Information System (INIS)

    This research thesis reports the study of stress corrosion resistance of stainless steels in caustic environments. It notably concerns the electronuclear industrial sector, the production of soda by electrolysis, and the preparation of hydrogen as energy vector. After a presentation of the experimental conditions, the author highlights the influence of purity on stress corrosion cracking of 20Cr-25Ni-type austenitic alloys. The specific action of a high number of addition metallic and non-metallic elements has been studied. Stress corrosion tests have been also performed in autoclave on austeno-ferritic (21 to 25 pc Cr - 6 to 10 pc Ni) as well as ferritic (26 pc Cr) grades. The author reports the study of electrochemical properties of stainless steel in soda by means of potentiostatic techniques with an application of Pourbaix thermodynamic equilibrium diagrams, and the study of the chemical composition of passivation thin layers by Auger spectroscopy. He more particularly studies the influence of electrode potential and of some addition elements on the chemical characteristics of oxides developed at the surface of austenite. Then, the author tries to establish correlations between strain hardening microstructure of the various steels and their sensitivity to stress corrosion

  6. Microstructure and helium irradiation performance of high purity tungsten processed by cold rolling

    Science.gov (United States)

    Chen, Zhe; Han, Wenjia; Yu, Jiangang; Kecskes, Laszlo; Zhu, Kaigui; Wei, Qiuming

    2016-10-01

    This work aims to investigate the effects of confined cold rolling on the evolution of microstructure, hardness, and helium irradiation performance of high purity tungsten (W). Using a final rolling temperature of 450 °C, W samples were severely deformed by confined cold rolling up to equivalent strains (εeq) of 1.6 and 3.3. Experimental results indicate that the average grain size of W specimens processed by confined cold rolling has been greatly reduced, and the rolled W samples with εeq ∼3.3 do not show an "ideal texture" of (001)[110] which is the expected texture of bcc metals processed by conventional cold rolling. The irradiation resistance against 60 keV He+ ions with up to a dose of 1.5 × 1022 ions·m-2 of the rolled W is compared to that of the as-received W. Results show that, due to an improvement of the metal's ductility, blister bursting with a partially opened lid forms on the surface of the rolled W, whereas blister bursting with a fully opened lid forms on the surface of the as-received W.

  7. Synthesis of high-purity Ti2AlN ceramic by hot pressing

    Institute of Scientific and Technical Information of China (English)

    YAN Ming; CHEN Yan-lin; MEI Bing-chu; ZHU Jiao-qun

    2008-01-01

    High-purity Ti2AlN ceramic was prepared at 1300 ℃ by hot pressing(HP) of Ti/Al/TiN powders in stoichiometric proportion. The sintered product was characterized using X-ray diffraction(XRD) and MDI Jade 5.0 software (Materials Data Inc, Liverpool, CA). Scanning electron microscopy(SEM) and electron probe micro-analysis(EPMA) coupled with energy-dispersive spectroscopy(EDS) were utilized to investigate the morphology characteristics. The results show that Ti2AlN phase is well-developed with a close and lamellar structure. The grains are plate-like with the size of 3-5 μm, thickness of 8-10 μm and elongated dimension. The density of Ti2AlN is measured to be 4.22 g/cm3, which reaches 97.9% of its theory value. The distribution of Ti2AlN grains is homogeneous.

  8. State of the art in high purity germanium systems for homeland security applications

    International Nuclear Information System (INIS)

    The IAEA initiated the Coordinated Research Project Improvement of Technical Measures to Detect and Respond to Illicit Trafficking of Nuclear and other Radioactive Materials in April 2002. The resultant reference manual was published in March 2006. In response to the needs expressed by the IAEA, ORTEC developed the Detective line of high purity germanium (HPGe) radioisotope identifiers (RIIDs). These are now well known and widely used. Several hundred are deployed worldwide in interdiction. The technology used in the Detective has been further developed to address two additional threat interdiction requirements. In the first, a smaller, lighter weight Detective-like device was developed by ORTEC and adapted to meet the needs of the US Human Portable Radiation Detection Systems (HPRDS) programme. The commercial version of this new instrument will be available in January 2008. The development programme and the new product are described. The second advancement is the broadening of the scope of the technology to address new applications for spectroscopic portal monitors as well as wide area search systems. ORTEC has developed modular hardware and software for use in a variety of portal and other configurations. In addition, a software model has been developed to predict portal performance in a variety of detectors and detector placement in these configurations. The hardware and software are described, and performance model data presented and compared to measurements in a pedestrian portal. (author)

  9. Safety studies conducted on a proprietary high-purity aloe vera inner leaf fillet preparation, Qmatrix.

    Science.gov (United States)

    Williams, Lonnie D; Burdock, George A; Shin, Eunju; Kim, Seunghyun; Jo, T H; Jones, Kenneth N; Matulka, Ray A

    2010-06-01

    The aloe vera plant has a long history of safe use for oral and topical applications. This publication describes safety studies conducted on a proprietary high-purity aloe vera inner leaf fillet preparation, Qmatrix. In a 13-week study in rats, Qmatrix was administered via gavage at 0, 500, 1000 and 2000 mg/kg body weight (bw)/day. There were no significant changes in food or water consumption, body weight, serum biochemistry or hematology at any of the doses tested. Sporadic, significant increases were observed in some of the measured urinalysis parameters; however, these variations were not treatment-related, as most were observed only in one sex, not dose-dependent and within historical control values. Organ weights were unaffected, except for a statistically significant, though not dose-dependent, increase in absolute and relative weights of the right kidney in males at 500 and 2000 mg/kg bw/day, respectively. Histopathological analysis revealed no abnormal signs. Qmatrix was non-mutagenic in an Ames test and a chromosomal aberration test at concentrations up to 10,000 microg/plate, and in an in vivo bone marrow micronucleus test at doses up to 5000 mg/kg bw/day. Based on these results, Qmatrix is not genotoxic in vitro or in vivo and; has an oral NOAEL greater than 2000 mg/kg bw/day following 90 days of oral exposure. PMID:20096744

  10. Interaction between a high purity magnesium surface and PCL and PLA coatings during dynamic degradation

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ying; Song Yang; Zhang Shaoxiang; Li Jianan; Zhao Changli; Zhang Xiaonong, E-mail: xnzhang@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2011-04-15

    In this study, polycaprolactone (PCL) and polylactic acid (PLA) coatings were prepared on the surface of high purity magnesium (HPMs), respectively, and electrochemical and dynamic degradation tests were used to investigate the degradation behaviors of these polymer-coated HPMs. The experimental results indicated that two uniform and smooth polymer films with thicknesses between 15 and 20 {mu}m were successfully prepared on the HPMs. Electrochemical tests showed that both PCL-coated and PLA-coated HPMs had higher free corrosion potentials (E{sub corr}) and smaller corrosion currents (I{sub corr}) in the modified simulated body fluid (m-SBF) at 37 {sup 0}C, compared to those of the uncoated HPMs. Dynamic degradation tests simulating the flow conditions in coronary arteries were carried out on a specific test platform. The weight of the specimens and the pH over the tests were recorded to characterize the corrosion performance of those samples. The surfaces of the specimens after the dynamic degradation tests were also examined. The data implied that there was a special interaction between HPM and its polymer coatings during the dynamic degradation tests, which undermined the corrosion resistance of the coated HPMs. A model was proposed to illustrate the interaction between the polymer coatings and HPM. This study also suggested that this reciprocity may also exist on the implanted magnesium stents coated with biodegradable polymers, which is a potential obstacle for the further development of drug-eluting magnesium stents.

  11. Abridged acid-base wet-milling synthesis of high purity hydroyapatite

    Directory of Open Access Journals (Sweden)

    Sandi Carolina Ruiz-Mendoza

    2008-06-01

    Full Text Available There is a plethora of routes to produce hydroxyapatite(HA and in general calcium phosphates(CP but production usually leads to a mixture of several phases. Besides ionic contamination, most of these methods are cumbersome, restricted to small volumes of product and require a lot of thermal energy. The acid-base route eliminates foreign ions or additives and its only byproduct is water. Heterogeneous reaction drawback is that solid reactants do not easily come in contact with each other and therefore addition and stirring times become very lengthy and still the product is a mixture. The synthesis started from calcium hydroxide and phosphoric acid (PA. Ball milling was used to favor kinetics and stoichiometry. Six sets of PA addition, paddle stirring and ball milling times were used. Products were evaluated by X ray diffraction (XRD, Fourier Transform Infrared (FTIR, scanning electron microscopy (SEM, X ray fluorescence (XRF and Ca/P ratio. Chemical analysis for calcium proceeded through oxalate precipitate and phosphorus by the phosphomolibdate technique. A set of conditions yielding high purity HA was established.

  12. GELATIO: a general framework for modular digital analysis of high-purity Ge detector signals

    CERN Document Server

    Agostini, M; Zavarise, P; Volynets, O

    2011-01-01

    GELATIO is a new software framework for advanced data analysis and digital signal processing developed for the GERDA neutrinoless double beta decay experiment. The framework is tailored to handle the full analysis flow of signals recorded by high purity Ge detectors and photo-multipliers from the veto counters. It is designed to support a multi-channel modular and flexible analysis, widely customizable by the user either via human-readable initialization files or via a graphical interface. The framework organizes the data into a multi-level structure, from the raw data up to the condensed analysis parameters, and includes tools and utilities to handle the data stream between the different levels. GELATIO is implemented in C++. It relies upon ROOT and its extension TAM, which provides compatibility with PROOF, enabling the software to run in parallel on clusters of computers or many-core machines. It was tested on different platforms and benchmarked in several GERDA-related applications. A stable version is pr...

  13. Electrical properties of as-grown and proton-irradiated high purity silicon

    Science.gov (United States)

    Krupka, Jerzy; Karcz, Waldemar; Kamiński, Paweł; Jensen, Leif

    2016-08-01

    The complex permittivity of as-grown and proton-irradiated samples of high purity silicon obtained by the floating zone method was measured as a function of temperature at a few frequencies in microwave spectrum by employing the quasi TE011 and whispering gallery modes excited in the samples under test. The resistivity of the samples was determined from the measured imaginary part of the permittivity. The resistivity was additionally measured at RF frequencies employing capacitive spectroscopy as well as in a standard direct current experiment. The sample of as-grown material had the resistivity of ∼85 kΩ cm at room temperature. The sample irradiated with 23-MeV protons had the resistivity of ∼500 kΩ cm at 295 K and its behavior was typical of the intrinsic material at room and at elevated temperatures. For the irradiated sample, the extrinsic conductivity region is missing and at temperatures below 250 K hopping conductivity occurs. Thermal cycle hysteresis of the resistivity for the sample of as-grown material is observed. After heating and subsequent cooling of the sample, its resistivity decreases and then slowly (∼50 h) returns to the initial value.

  14. Effectiveness of a high purity chlorine dioxide solution in eliminating intracanal Enterococcus faecalis biofilm.

    Science.gov (United States)

    Herczegh, Anna; Ghidan, Agoston; Friedreich, Dóra; Gyurkovics, Milán; Bendő, Zsolt; Lohinai, Zsolt

    2013-03-01

    We investigated the effectiveness of chlorine dioxide (ClO2) solution in comparison to sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) in the elimination of intracanal Enterococcus faecalis biofilm. Extracted human teeth were inoculated with E. faecalis. After preparation the canals were irrigated with ClO2, NaOCl, CHX or physiologic saline for control. Two and five days later bacterial samples were collected and streaked onto Columbia agar. CFU/mL were counted. The canal walls were investigated by scanning electron microscopy (SEM). The gas phase was investigated in an upside down Petri dish where E. faecalis was inoculated onto blood agar. The irrigants were placed on absorbent paper into the cover. Bacteria were detectable in the control group, but not in any of the irrigants groups. There was a massive reinfection 2 or 5 days after irrigation in the control group. The lowest reinfection was found after the ClO2 treatment. These findings were confirmed by SEM images. We observed an antibacterial effect of ClO2 and NaOCl gas phases on E. faecalis growth, but not of CHX. ClO2 eliminates intracanal biofilm and keeps canal nearly free from bacteria. We suggest the use of high purity ClO2 as a root canal irrigant in clinical practice. PMID:23529300

  15. Synthesis of high purity monoglycerides from crude glycerol and palm stearin

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2008-07-01

    Full Text Available The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process werefound to be a reaction temperature of 200oC with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction timeof 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared withthe glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glyceroland crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed byadding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved byusing isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35oC. A purity notexceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.

  16. Production of High Purity Multi-Walled Carbon Nanotubes from Catalytic Decomposition of Methane

    Institute of Scientific and Technical Information of China (English)

    Kong Bee Hong; Aidawati Azlin Binti Ismail; Mohamed Ezzaham Bin Mohd Mahayuddin; Abdul Rahman Mohamed; Sharif Hussein Sharif Zein

    2006-01-01

    Acid-based purification process of multi-walled carbon nanotubes (MWNTs) produced via catalytic decomposition of methane with NiO/TiO2 as a catalyst is described. By combining the oxidation in air and the acid refluxes, the impurities, such as amorphous carbon, carbon nanoparticles, and the NiO/TiO2 catalyst, are eliminated. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirm the removal of the impurities. The percentage of the carbon nanotubes purity was analyzed using thermal gravimetric analysis (TGA). Using this process, 99.9 wt% purity of MWNTs was obtained.

  17. Supercapacitor Electrodes Based on High-Purity Electrospun Polyaniline and Polyaniline-Carbon Nanotube Nanofibers.

    Science.gov (United States)

    Simotwo, Silas K; DelRe, Christopher; Kalra, Vibha

    2016-08-24

    Freestanding, binder-free supercapacitor electrodes based on high-purity polyaniline (PANI) nanofibers were fabricated via a single step electrospinning process. The successful electrospinning of nanofibers with an unprecedentedly high composition of PANI (93 wt %) was made possible due to blending ultrahigh molecular weight poly(ethylene oxide) (PEO) with PANI in solution to impart adequate chain entanglements, a critical requirement for electrospinning. To further enhance the conductivity and stability of the electrodes, a small concentration of carbon nanotubes (CNTs) was added to the PANI/PEO solution prior to electrospinning to generate PANI/CNT/PEO nanofibers (12 wt % CNTs). Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) porosimetry were conducted to characterize the external morphology of the nanofibers. The electrospun nanofibers were further probed by transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The electroactivity of the freestanding PANI and PANI/CNT nanofiber electrodes was examined using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Competitive specific capacitances of 308 and 385 F g(-1) were achieved for PANI and PANI-CNT based electrodes, respectively, at a current density of 0.5 A g(-1). Moreover, specific capacitance retentions of 70 and 81.4% were observed for PANI and PANI-CNT based electrodes, respectively, after 1000 cycles. The promising electrochemical performance of the fabricated electrodes, we believe, stems from the porous 3-D electrode structure characteristic of the nonwoven interconnected nanostructures. The interconnected nanofiber network facilitates efficient electron conduction while the inter- and intrafiber porosity enable excellent electrolyte penetration within the polymer matrix, allowing fast ion transport to the active sites. PMID:27467445

  18. Porous and mesh alumina formed by anodization of high purity aluminum films at low anodizing voltage

    Energy Technology Data Exchange (ETDEWEB)

    Abd-Elnaiem, Alaa M., E-mail: alaa.abd-elnaiem@science.au.edu.eg [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Mebed, A.M. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Department of Physics, Faculty of Science, Al-Jouf University, Sakaka 2014 (Saudi Arabia); El-Said, Waleed Ahmed [Department of Chemistry, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Abdel-Rahim, M.A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt)

    2014-11-03

    Electrochemical oxidation of high-purity aluminum (Al) films under low anodizing voltages (1–10) V has been conducted to obtain anodic aluminum oxide (AAO) with ultra-small pore size and inter-pore distance. Different structures of AAO have been obtained e.g. nanoporous and mesh structures. Highly regular pore arrays with small pore size and inter-pore distance have been formed in oxalic or sulfuric acids at different temperatures (22–50 °C). It is found that the pore diameter, inter-pore distance and the barrier layer thickness are independent of the anodizing parameters, which is very different from the rules of general AAO fabrication. The brand formation mechanism has been revealed by the scanning electron microscope study. Regular nanopores are formed under 10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultra-small nanopores. Anodization that is performed at voltages less than 5 V leads to mesh structured alumina. In addition, we have introduced a simple one-pot synthesis method to develop thin walls of oxide containing lithium (Li) ions that could be used for battery application based on anodization of Al films in a supersaturated mixture of lithium phosphate and phosphoric acid as matrix for Li-composite electrolyte. - Highlights: • We develop anodic aluminum oxide (AAO) with small pore size and inter-pore distance. • Applying low anodizing voltages onto aluminum film leads to form mesh structures. • The value of anodizing voltage (1–10 V) has no effect on pore size or inter-pore distance. • Applying anodizing voltage less than 5 V leads to mesh structured AAO. • AAO can be used as a matrix for Li-composite electrolytes.

  19. High Magnetic Field Influence on the Widmanstaitten Transformation in High Purity Fe-0.36 wt% C Alloy

    Institute of Scientific and Technical Information of China (English)

    Shoujing Wang,; Xiang Zhao; Na Xiao; Liang Zuo

    2012-01-01

    The influence of high magnetic field with different strength on the proeutectoid ferrite transformation in high purity Fe-0.36 wt% C during diffusional Υ phase transformation was studied. It was found that the formation of acicular ferrite (ie. Widmanst3tten ferrite) was obviously suppressed by the applied high magnetic field. The stronger the magnetic field is, the more the ferrite grains elongating and aligning along the field direction will be. This is attributed to additional driving force for phase transformation and demagnetization effect introduced by the applied magnetic field. This is also considered to be related to the preferential growth of proeutectoid ferrite nuclei along field direction caused by magnetic dipolar interaction.

  20. Development of High-purity Certified Reference Materials for 17 Proteinogenic Amino Acids by Traceable Titration Methods.

    Science.gov (United States)

    Kato, Megumi; Yamazaki, Taichi; Kato, Hisashi; Eyama, Sakae; Goto, Mari; Yoshioka, Mariko; Takatsu, Akiko

    2015-01-01

    To ensure the reliability of amino acid analyses, the National Metrology Institute of Japan of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed high-purity certified reference materials (CRMs) for 17 proteinogenic amino acids. These CRMs are intended for use as primary reference materials to enable the traceable quantification of amino acids. The purity of the present CRMs was determined based on two traceable methods: nonaqueous acidimetric titration and nitrogen determination by the Kjeldahl method. Since neither method could distinguish compounds with similar structures, such as amino acid-related impurities, impurities were thoroughly quantified by combining several HPLC methods, and subtracted from the obtained purity of each method. The property value of each amino acid was calculated as a weighted mean of the corrected purities by the two methods. The uncertainty of the property value was obtained by combining measurement uncertainties of the two methods, a difference between the two methods, the uncertainty from the contribution of impurities, and the uncertainty derived from inhomogeneity. The uncertainty derived from instability was considered to be negligible based on stability monitoring of some CRMs. The certified value of each amino acid, property value with uncertainty, was given for both with or without enantiomeric separation.

  1. Raman and photoelectron spectroscopic investigation of high-purity niobium materials: Oxides, hydrides, and hydrocarbons

    Science.gov (United States)

    Singh, Nageshwar; Deo, M. N.; Nand, Mangla; Jha, S. N.; Roy, S. B.

    2016-09-01

    We present investigations of the presence of oxides, hydrides, and hydrocarbons in high-purity (residual resistivity ratio, ˜300) niobium (Nb) materials used in fabrication of superconducting radio frequency (SRF) cavities for particle accelerators. Raman spectroscopy of Nb materials (as-received from the vendor as well as after surface chemical- and thermal processing) revealed numerous peaks, which evidently show the presence of oxides (550 cm-1), hydrides (1277 and 1385 cm-1: ˜80 K temperature), and groups of hydrocarbons (1096, 2330, 2710, 2830, 2868, and 3080 cm-1). The present work provides direct spectroscopic evidence of hydrides in the electropolished Nb materials typically used in SRF cavities. Raman spectroscopy thus can provide vital information about the near-surface chemical species in niobium materials and will help in identifying the cause for the performance degradation of SRF cavities. Furthermore, photoelectron spectroscopy was performed on the Nb samples to complement the Raman spectroscopy study. This study reveals the presence of C and O in the Nb samples. Core level spectra of Nb (doublet 3d5/2 and 3d3/2) show peaks near 206.6 and 209.4 eV, which can be attributed to the Nb5+ oxidation state. The core level spectra of C 1 s of the samples are dominated by graphitic carbon (binding energy, 284.6 eV), while the spectra of O 1 s are asymmetrically peaked near binding energy of ˜529 eV, and that indicates the presence of metal-oxide Nb2O5. The valence-band spectra of the Nb samples are dominated by a broad peak similar to O 2p states, but after sputtering (for 10 min) a peak appears at ˜1 eV, which is a feature of the elemental Nb atom.

  2. Stability of Y-90 Zevalin: Radiochemical purity evaluation using instant thin layer and size exclusion high performance liquid chromatography

    International Nuclear Information System (INIS)

    Aim: The purpose of the study was to evaluate the stability of typical Y-90 Zevalin (IDEC Pharmaceuticals Corp) patient doses, either maintained at room temperature or refrigerated, using the manufacturer's recommended instant thin layer chromatography procedure and confirming the results using size exclusion high performance liquid chromatography (HPLC) to evaluate radiochemical purity. Material and Methods: Following radiolabeling of Y-90 Zevalin, two patient doses were withdrawn into a 10-ml syringe. One patient dose, consisting of 41.2 mCi Y-90 Zevalin in 10 ml, was refrigerated. The other patient dose, consisting of 31.2 mCi Y-90 Zevalin in 7.3 ml, was maintained at room temperature. At selected time intervals after formulation, ranging from 0.5 to 49 hrs, radiochemical purity evaluations were performed using instant thin layer chromatography (ITLC-SG) with normal saline and size exclusion HPLC using a TSKgel G3000SW molecular sizing column. For each time interval, five separate samples were analyzed and the data statistically summarized. Results: Following initial radiolabeling, the radiochemical purity of all preparations evaluated was greater than 95%, as demonstrated by both chromatographic methods. At 24 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 95.4% ± 0.3% (s.d.) and 86.3% ± 1.2% (s.d), respectively using instant thin layer chromatography. At 48 hours post radiolabeling, the mean radiochemical purity of Y-90 Zevalin, refrigerated or maintained at room temperature, was 91.0% ±± 0.8% (s.d.) and 86.0% ± 2.0% (s.d.), respectively using instant thin layer chromatography. In general, size exclusion HPLC confirmed the chromatographic results. With increased time post radiolabeling, an increase in radiolabeled low molecular weight components (Y-90 DTPA) and an increase in radiolabeled high molecular weight components and/or aggregates was observed. These radiochemical

  3. Cross Purposes: Love and Purity at a Puerto Rican Protestant High School

    Science.gov (United States)

    Seale-Collazo, James

    2013-01-01

    A "native" Christian ethnographer finds religious education at this church-sponsored school to pursue two distinct, and occasionally conflicting, curricula: "love" and "purity." The curriculum of love draws on what Turner called liminality and communitas in an effort to promote spiritual "encounters with…

  4. Efficient continuous synthesis of high purity deep eutectic solvents by twin screw extrusion.

    Science.gov (United States)

    Crawford, D E; Wright, L A; James, S L; Abbott, A P

    2016-03-01

    Mechanochemical synthesis has been applied to the rapid synthesis of Deep Eutectic Solvents (DESs), including Reline 200 (choline chloride : urea, 1 : 2), in a continuous flow methodology by Twin Screw Extrusion (TSE). This gave products in higher purity and with Space Time Yields (STYs), four orders of magnitude greater than for batch methods. PMID:26911554

  5. Diffusion bonding and brazing of high purity copper for linear collider accelerator structures

    Science.gov (United States)

    Elmer, J. W.; Klingmann, J.; van Bibber, K.

    2001-05-01

    Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC). Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi) and 3.45 MPa (500 psi)], and on two different diamond machined surface finishes. Brazes were made using pure silver, pure gold, and gold-nickel alloys, and different heating rates produced by both radiation and induction heating. Braze materials were applied by both physical vapor deposition (PVD) and conventional braze alloy shims. Results of the diffusion bonding experiments showed that bond strengths very near that of the copper base metal could be made at bonding temperatures of 700 °C or higher at 3.45 MPa bonding pressure. At lower temperatures, only partial strength diffusion bonds could be made. At low bonding pressures (3.45 kPa), full strength bonds were made at temperatures of 800 °C and higher, while no bonding (zero strength) was observed at temperatures of 700 °C and lower. Observations of the fracture surfaces of the diffusion bonded samples showed the effects of surface finish on the bonding mechanism. These observations clearly indicate that bonding began by point asperity contact, and flatter surfaces resulted in a higher percentage of bonded area under similar bonding conditions. Results of the brazing experiments indicated that pure silver worked very well for brazing under both conventional and high heating rate scenarios. Similarly, pure silver brazed well for both the PVD layers and the braze alloy shims. The gold and gold-containing brazes had problems, mainly due to the high diffusivity of gold in copper. These problems led to the necessity of overdriving the temperature to ensure melting, the presence of porosity in the joint, and very wide braze joints. Based on the overall findings of this study, a two-step joining method

  6. Characterization of deposits build-up on austenitic stainless steel AISI 316L exposed in high purity water system

    International Nuclear Information System (INIS)

    For the characterization of deposit layers on AISI 316L surfaces in high purity water systems, operating up to 80 deg C Moessbauer spectroscopy (ME), scanning electron microscopy (SEM), X-ray fluorescence (XRF) and X-ray photoelectron spectroscopy (XPS) are used. Austenitic steel particles were identified on the surfaces of systems not properly cleaned before start-up. Long exposition of austenitic surfaces to high purity water promotes the build-up, composed by trivalent iron and chromium oxidehydroxides and oxide. The oxidehydroxide phase is located mainly at the solid-water interface, whereas oxide phase is in direct contact with metal. Spheroid-like morphology of particles in these layers and the lack of metal attack suggest that coagulation and crystallization processes are the way for oxide production from existing dissolved species. (author)

  7. Potential utility of eGFP-expressing NOG mice (NOG-EGFP as a high purity cancer sampling system

    Directory of Open Access Journals (Sweden)

    Shima Kentaro

    2012-06-01

    Full Text Available Abstract Purpose It is still technically difficult to collect high purity cancer cells from tumor tissues, which contain noncancerous cells. We hypothesized that xenograft models of NOG mice expressing enhanced green fluorescent protein (eGFP, referred to as NOG-EGFP mice, may be useful for obtaining such high purity cancer cells for detailed molecular and cellular analyses. Methods Pancreato-biliary cancer cell lines were implanted subcutaneously to compare the tumorigenicity between NOG-EGFP mice and nonobese diabetic/severe combined immunodeficiency (NOD/SCID mice. To obtain high purity cancer cells, the subcutaneous tumors were harvested from the mice and enzymatically dissociated into single-cell suspensions. Then, the cells were sorted by fluorescence-activated cell sorting (FACS for separation of the host cells and the cancer cells. Thereafter, the contamination rate of host cells in collected cancer cells was quantified by using FACS analysis. The viability of cancer cells after FACS sorting was evaluated by cell culture and subsequent subcutaneous reimplantation in NOG-EGFP mice. Results The tumorigenicity of NOG-EGFP mice was significantly better than that of NOD/SCID mice in all of the analyzed cell lines (p  Conclusions This method provides a novel cancer sampling system for molecular and cellular analysis with high accuracy and should contribute to the development of personalized medicine.

  8. Application of multisection packing concept to sorption-enhanced steam methane reforming reaction for high-purity hydrogen production

    Science.gov (United States)

    Lee, Chan Hyun; Mun, Sungyong; Lee, Ki Bong

    2015-05-01

    Hydrogen has been gaining popularity as a new clean energy carrier, and bulk hydrogen production is achieved through the steam methane reforming (SMR) reaction. Since hydrogen produced via the SMR reaction contains large amounts of impurities such as unreacted reactants and byproducts, additional purification steps are needed to produce high-purity hydrogen. By applying the sorption-enhanced reaction (SER), in which catalytic reaction and CO2 byproduct removal are carried out simultaneously in a single reactor, high-purity hydrogen can be directly produced. Additionally, the thermodynamic limitation of conventional SMR reaction is circumvented, and the SMR reaction process becomes simplified. To improve the performance of the SER, a multisection packing concept was recently proposed. In this study, the multisection packing concept is experimentally demonstrated by applying it to a sorption-enhanced SMR (SE-SMR) reaction. The experimental results show that the SE-SMR reaction is significantly influenced by the reaction temperature, owing to the conflicting dependence of the reaction rate and the CO2 sorption uptake on the reaction temperature. Additionally, it is confirmed that more high-purity hydrogen (<10 ppm of CO) can be produced by applying the multisection packing concept to the SE-SMR reactions operated at sufficiently high temperatures where the SMR reaction is not limited by rate.

  9. Impurity analyses of high-purity carbon monoxide gas using micro gas chromatography for development as a certified reference material.

    Science.gov (United States)

    Matsumoto, Nobuhiro; Watanabe, Takuro; Kato, Kenji

    2013-03-22

    High-purity carbon monoxide (CO) gas as a certified reference material (CRM) was analyzed using a micro gas chromatograph (micro-GC) with a micro thermal conductivity detector. The main reason to select the micro-GC was its compact size to provide a safe experimental environment. Thus, both the CO gas cylinder and the micro-GC were placed inside a draft shield with a limited small space. Peaks of several impurities were found in chromatograms of the micro-GC. The main impurities in the CO gas were helium, hydrogen, oxygen, nitrogen and carbon dioxide. It was found that helium was the impurity of the highest concentration. High-accuracy calibration gas mixtures were used to construct calibration lines for the micro-GC. The mixtures were precisely prepared by the gravimetric blending method. Calibration lines had enough linearity and accuracy for quantitative analyses of the impurities. The values of detection limit of the impurities were 0.7-4μmol/mol. The purity of the high-purity CO gas was around 99.996%, which was the value estimated from the sum of the concentrations of the impurities. PMID:23415447

  10. Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

    International Nuclear Information System (INIS)

    Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

  11. Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

    Energy Technology Data Exchange (ETDEWEB)

    Volynets, Oleksandr

    2012-07-27

    Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.

  12. Ion irradiation effects on high purity bcc Fe and model FeCr alloys

    International Nuclear Information System (INIS)

    FeCr binary alloys are a simple representative of the reduced activation ferritic/martensitic (F-M) steels, which are currently the most promising candidates as structural materials for the sodium cooled fast reactors (SFR) and future fusion systems. However, the impact of Cr on the evolution of the irradiated microstructure in these materials is not well understood in these materials. Moreover, particularly for fusion applications, the radiation damage scenario is expected to be complicated further by the presence of large quantities of He produced by the nuclear transmutation (∼ 10 appm He/dpa). Within this context, an elaborate ion irradiation study was performed at 500 C on a wide variety of high purity FeCr alloys (with Cr content ranging from ∼ 3 wt.% to 14 wt.%) and a bcc Fe, to probe in detail the influence of Cr and He on the evolution of microstructure. The irradiations were performed using Fe self-ions, in single beam mode and in dual beam mode (damage by Fe ions and co-implantation of He), to separate ballistic damage effect from the impact of simultaneous He injection. Three different dose ranges were studied: high dose (157 dpa, 17 appm He/dpa for the dual beam case), intermediate dose (45 dpa, 57 appm He/dpa for dual beam case) and in-situ low dose (0.33 dpa, 3030 appm He/dpa for the dual beam case). The experiments were performed at the JANNuS triple beam facility and dual beam in situ irradiation facility at CEA-Saclay and CSNSM, Orsay respectively. The microstructure was principally characterized by conventional TEM, APT and EDS in STEM mode. The main results are as follows: 1) A comparison of the cavity microstructure in high dose irradiated Fe revealed strong swelling reduction by the addition of He. It was achieved by a drastic reduction in cavity sizes and an increased number density. This behaviour was observed all along the damage depth, up to the damage peak. 2) Cavity microstructure was also studied in the dual beam high dose

  13. Effects of electric field on recrystallization texture evolution in cold-rolled high-purity aluminum sheet during annealing

    Institute of Scientific and Technical Information of China (English)

    WU Yan; ZHAO Xiang; HE Chang-shu; ZHAO Zhi-peng; ZUO Liang; C. ESLING

    2007-01-01

    The effects of an external DC (direct current) electric field on recrystallization texture evolution in the cold-rolled aluminum sheets with 99.99% purity were investigated by means of X-ray diffraction techniques. The cold-rolled high-purity aluminum sheets were annealed for 60 min at 200, 300 and 400 ℃, respectively with and without an external DC electric field of 800 V/mm. The results show that with DC electric field, the recrystallization cube texture is strengthened at the stage of grain growth. Possible reason for the strengthening of the recrystallization cube texture with the applied electric field may be attributed to both selected nucleation and selected growth of cube oriented crystal nuclei.

  14. Photocatalytic Degradation of Rhodamine B Dye with High Purity Anatase Nano-TiO2 Synthesized by a Hydrothermal Method

    Institute of Scientific and Technical Information of China (English)

    SHI Xiaoliang; YANG Xingyong; WANG Shuwei; WANG Sheng; ZHANG Qiaoxin; WANG Yufu

    2011-01-01

    High purity anatase nano-TiO2 powders with high photocatalytic activity were prepared by a hydrothermal synthesis method.X-ray diffraction(XRD),field emission transmission electron microscopy (FETEM),ultraviolet-visible(UV-Vis)light absorption spectrum and photoluminescence(PL)spectrum were adopted to characterize the catalyst.Effects of temperature,time and sol concentration of hydrothermal synthesis on particle size and phases were investigated.Photocatalytic activities in the degradation of Rhodamine B Dye were studied.The experimental results indicated that photocatalytic activity of the nano-TiO2 powers was much higher than that of P25(Degussa).

  15. Considering Process Nonlinearity in Dual-Point Composition Control of a High-Purity Ideal Heat Integrated Distillation Column

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Dual-point composition control for a high-purity ideal heat integrated distillation column (HIDiC) is addressed in this work. Three measures are suggested and combined for overcoming process inherent nonlinearities:(1) variable scaling; (2) multi-model representation of process dynamics and (3) feedforward compensation. These strategies can offer the developed control systems with several distinct advantages: (1) capability of dealing with severe disturbances; (2) tight tuning of controller parameters and (3) high robustness with respect to variation of operating conditions. Simulation results demonstrate the effectiveness of the proposed methodology.

  16. Processing and properties of high-purity, fine-grain-size depleted-uranium, deep-drawn shapes

    International Nuclear Information System (INIS)

    Unalloyed uranium is a candidate material for shaped charge liners used in conventional ordinance applications. For test purposes, it was decided that a high-grade uranium material with good toughness should be used. This report describes a process for producing a high-purity (less than 500 ppM total impurities) wrought material consisting of a recrystallized, equiaxed grain structure with a 10 micron (ASTM-8) average grain size. The fabrication process is discussed in detail. In all, six material conditions having a wide range of mechanical and structural properties were investigated. The tensile, hardness, and microstructural properties of these six material conditions are reported in detail

  17. High Purity Hydrogen Production with In-Situ Carbon Dioxide and Sulfur Capture in a Single Stage Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nihar Phalak; Shwetha Ramkumar; Daniel Connell; Zhenchao Sun; Fu-Chen Yu; Niranjani Deshpande; Robert Statnick; Liang-Shih Fan

    2011-07-31

    Enhancement in the production of high purity hydrogen (H{sub 2}) from fuel gas, obtained from coal gasification, is limited by thermodynamics of the water gas shift (WGS) reaction. However, this constraint can be overcome by conducting the WGS in the presence of a CO{sub 2}-acceptor. The continuous removal of CO{sub 2} from the reaction mixture helps to drive the equilibrium-limited WGS reaction forward. Since calcium oxide (CaO) exhibits high CO{sub 2} capture capacity as compared to other sorbents, it is an ideal candidate for such a technique. The Calcium Looping Process (CLP) developed at The Ohio State University (OSU) utilizes the above concept to enable high purity H{sub 2} production from synthesis gas (syngas) derived from coal gasification. The CLP integrates the WGS reaction with insitu CO{sub 2}, sulfur and halide removal at high temperatures while eliminating the need for a WGS catalyst, thus reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors - the carbonator, where the thermodynamic constraint of the WGS reaction is overcome by the constant removal of CO{sub 2} product and high purity H{sub 2} is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready CO{sub 2} stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. As a part of this project, the CLP was extensively investigated by performing experiments at lab-, bench- and subpilot-scale setups. A comprehensive techno-economic analysis was also conducted to determine the feasibility of the CLP at commercial scale. This report provides a detailed account of all the results obtained during the project period.

  18. A facile approach for synthesizing Fe-based layered double hydroxides with high purity and its exfoliation.

    Science.gov (United States)

    Wang, Yinling; Li, Fajun; Dong, Shengye; Liu, Xiaowang; Li, Maoguo

    2016-04-01

    Transition metal (e.g., Fe, Co, Ni)-based layered double hydroxides (LDHs) and their exfoliated nanosheets have great potential applications due to their redox and magnetic properties. Here we report a facile approach for the preparation of Co-Fe LDHs with good crystallinity and high purity. The proposed approach includes two steps: (1) The mixed divalent metal (e.g., Co(2+), Fe(2+)) hydroxides were first synthesized using a homogeneous precipitation without piping N2 into the system; hexamethylenetetramine (HMT) was the hydrolysis agent providing OH(-), and hydroxylamine hydrochloride (HAH) was used as both a reducing and a complexing reagent. (2) Then the as-prepared hydroxides were slowly oxidated by air and simultaneously intercalated by CO3(2-) to form CO3-intercalated LDHs. The Co-Fe LDHs were roundly characterized by XRD, SEM, EDX and FT-IR. The effect of HAH on the morphology and structure of the Co-Fe LDHs was also studied. The magnetism of Co-Fe LDHs at room temperature was investigated and the results showed that the LDHs displayed a low saturation magnetization value of 6.3emug(-1), suggesting that the purity of the products was very high. In addition, the intercalated CO3(2-) in the Co-Fe LDHs could be successfully exchanged with other anions such as Cl(-) and ClO4(-). Furthermore, the exchanged-LDHs could be exfoliated in formamide. This work establishes a new method for the synthesis of Fe-based LDHs with good crystallinity and high purity under mild conditions, and can accelerate the development of applications using these layered materials. PMID:26773611

  19. High-Frequency Electrodeless Quartz Crystal Microbalance Chip with a Bare Quartz Resonator Encapsulated in a Silicon Microchannel

    Science.gov (United States)

    Kato, Fumihito; Ogi, Hirotsugu; Yanagida, Taiji; Nishikawa, Shintaro; Nishiyama, Masayoshi; Hirao, Masahiko

    2011-07-01

    We present a high-frequency electrodeless quartz crystal microbalance (QCM) chip with a bare quartz resonator encapsulated in a silicon microchannel, which is fabricated by micromachining technology. This QCM chip packages an AT-cut quartz plate 2.5 mm long, 1.7 mm wide, and 9.6 µm thick, which is supported by micropillars without fixed parts. There is no issue about destruction during assembly because handling the fragile quartz resonator becomes unnecessary. The quartz resonator is electrodeless and not fixed; therefore, there are no losses due to electrodes and contacting wires. As a result, a high quality factor (Q-factor) and a high signal-to-noise ratio (SNR) can be obtained. The Q-factor is about 800-2800 at 170 MHz in the flow of the carrier solution. In addition, it is possible to reuse the device, because the quartz surfaces can adsorb receptor proteins nonspecifically, which can be removed by a washing procedure with a strong acid solution flowed in the microchannel. The high-frequency quartz resonator (170 MHz) encapsulated in the microchannel can reduce the influence of the viscosity contribution to the frequency shift, achieving highly sensitive and quantitative analysis. The QCM chip is excited and detects the shear vibrations of the quartz resonator by the line antennas without contact. Consequently, both sides of the quartz resonator can be used as the detection area in a solution. We succeeded in detecting the human immunoglobulin G (hIgG) at a concentration of 6 µg/ml via the staphylococcal protein A (SPA) immobilized nonspecifically on the developed QCM chip in real time without any labeling.

  20. Magnetic and magnetothermal properties and the magnetic phase diagram of high purity single crystalline terbium along the easy magnetization direction.

    Science.gov (United States)

    Zverev, V I; Tishin, A M; Chernyshov, A S; Mudryk, Ya; Gschneidner, K A; Pecharsky, V K

    2014-02-12

    The magnetic and magnetothermal properties of a high purity terbium single crystal have been re-investigated from 1.5 to 350 K in magnetic fields ranging from 0 to 75 kOe using magnetization, ac magnetic susceptibility and heat capacity measurements. The magnetic phase diagram has been refined by establishing a region of the fan-like phase broader than reported in the past, by locating a tricritical point at 226 K, and by a more accurate definition of the critical fields and temperatures associated with the magnetic phases observed in Tb.

  1. Spectrographic determination of lanthanides in high-purity uranium compounds, after chromatographic separation by alumina-hydrofluoric acid

    International Nuclear Information System (INIS)

    A method is presented for the determination of fourteen rare earth elements in high-purity uranium compounds by emission spectrography. The rare earths are chromatographically separated from uranium by using alumina-hydrofluoric acid. Lanthanum is used both as collector and internal standard. The technique of excitation involves a total consumption of the sample in a 17 ampere direct current arc. The range of determination is about 0.005 to 0.5 μg/g uranium. The coefficient of variation for Pr, Ho, Dy, Er, Tm, Lu, Gd and Tb amounts to 10%. (Author)

  2. Mechanical energy losses in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zelada, Griselda I. [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Lambri, Osvaldo Agustin [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Instituto de Fisica Rosario - CONICET, Member of the CONICET& #x27; s Research Staff, Avda. Pellegrini 250, 2000 Rosario (Argentina); Bozzano, Patricia B. [Laboratorio de Microscopia Electronica, Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, 1650 San Martin (Argentina); Garcia, Jose Angel [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2012-10-15

    Mechanical spectroscopy (MS) and transmission electron microscopy (TEM) studies have been performed in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum, oriented for single slip, in order to study the dislocation dynamics in the temperature range within one third of the melting temperature. A damping peak related to the interaction of dislocation lines with both prismatic loops and tangles of dislocations was found. The peak temperature ranges between 900 and 1050 K, for an oscillating frequency of about 1 Hz. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Dual-Frequency 780-nm Ti:Sa Laser for High Spectral Purity Tunable CW THz Generation

    OpenAIRE

    Loas, Goulc'Hen; Romanelli, Marco; Alouini, Mehdi

    2014-01-01

    International audience — A two-axis, two-polarization, dual-frequency Ti:Sa laser optimized for high spectral purity CW-THz generation is demonstrated. The laser output power is 50mW. Its mean emission wavelength is optimized around 780nm in order to suit the maximum efficiency of low temperature grown GaAs photomixers. Despite the extremely wide gain bandwidth of Ti:Sa, a proper intracavity filtering design, adapted to this particular laser architecture, enables tunable and single-frequen...

  4. Stress corrosion cracking behavior of newer iron--chromium--nickel alloys at 5500F in high purity water

    International Nuclear Information System (INIS)

    As part of a long range materials development program, new commercial plant materials were evaluated for future BWR applications. These materials include ferritic, martensitic, austenitic, and austeno-ferritic stainless steels. Each alloy was characterized for chemical composition, microstructure, and mechanical properties. Stress corrosion cracking screening tests were performed in 5500F, high-purity water containing 36 ppM oxygen on uniaxial tensile specimens stressed at 75 percent of the 5500F ultimate tensile strength. Tests were continued to 5000 hours or failure which ever occurred first. Post-test metallographic examinations were performed on the failed specimen. Results of the evaluation program are presented. 12 fig, 3 tables

  5. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

    Science.gov (United States)

    Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

    2012-07-03

    In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

  6. High-purity Ni electroless plating on screen-printed anodized Al substrates

    Science.gov (United States)

    Park, Sang-Geon; Lee, Youn-Seoung; Rha, Sa-Kyun

    2016-07-01

    By using an electroless plating process with a Ni source solution including dimethylamine borane (DMAB) at pH 6.5 and 65 ◦ C, we obtained a higher purity Ni film (resistance (Rs) at the interface region is due to the change in the boron concentration caused by surface reactions, and the gradual decrease in Rs in the bulk region is due mainly to the effect of the saturation of boron's concentration on the thickness. From a boron-distribution viewpoint, this result indicates that the B concentration in the Ni film increases gradually with increasing plating time for plating times ≤ 60 s as a kind of initial stage (that is, interface region), and then saturates uniformly for plating times ≥ 300 s as a kind of bulk region. On the other hand, from an electronic structure viewpoint, this result implies that Ni gains 3d electrons with respect to elemental Ni. The increase in the number of electrons gained by the Ni 3d states may result in an enhancement of the electrical conductivity.

  7. High-purity biodiesel production from microalgae and added-value lipid extraction: a new process.

    Science.gov (United States)

    Veillette, M; Giroir-Fendler, A; Faucheux, N; Heitz, M

    2015-01-01

    A new process was tested in order to produce and purify biodiesel from microalgae lipids and to recover unsaponifiable (added-value) lipids. This process is a two-step biodiesel production including a saponification reaction step followed by an esterification reaction step. The process includes a recovery of the unsaponified lipids between both reaction steps. Among the conditions tested, the following conditions were found to be the best: temperature for both steps (90 °C), saponification time (30 min), esterification time (30 min), sulfuric acid/potassium hydroxide (1.21, w/w), and methanol-lipid ratio (13.3 mL/g). Under these conditions, the fatty acid methyl ester (FAME) yield and the biodiesel purity were, respectively, 32% (g FAME/g lipid) and 77% (g FAME/g biodiesel). This study also showed that the two-step biodiesel process allows a FAME mass composition rich in palmitate (27.9-29.4 wt%), palmitoleate (24.9-26.0 wt%), elaidate (14.8-15.2 wt%), and myristate (12.1-13.0 wt%).

  8. AN IMPROVED METHOD FOR ISOLATING RESIDUAL KRAFT LIGNIN IN HIGH YIELD AND PURITY

    Institute of Scientific and Technical Information of China (English)

    Shubin Wu; Dimitris S.Argyropoulos

    2004-01-01

    When washed pulps is milled and ground to a fine powder, the resulting material may easily be degraded by cellulolytic enzymes. The klason and UV lignin content of the solid residuals obtained in this step were 49.9% lignin for spruce KP, and 21.4% for poplar KP. The solid residuals from enzymatic treatment contained about 93.3% and 90.7% of the lignin originally presented in the spruce KP and poplar KP respectively. The enzymatic treated residual was then subjected to mild acidolysis, which caused the cleavage of lignin-carbohydrate linkages.The resulting Ground Enzymatic/Acidolysis Kraft Lignin (GEA-KL) is of significantly higher yield than our previous two-step (enzymatic/acidolysis) residual kraft lignin (EA-KL). The improved method offers kraft lignin preparations in higher yield and purity than any other known method with minimal work up and solvent requirements. DFRC/quantitative 31p NMR protocol and quantitative DEPT edited 13C RMR were used for characterizing of RKLs.

  9. AN IMPROVED METHOD FOR ISOLATING RESIDUAL KRAFT LIGNIN IN HIGH YIELD AND PURITY

    Institute of Scientific and Technical Information of China (English)

    ShubinWu; DimitrisS.Argyropoulos

    2004-01-01

    When washed pulps is milled and ground to a fine powder, the resulting material may easily be degraded by cellulolytic enzymes. The klason and UV lignin content of the solid residuals obtained in this step were 49.9% lignin for spruce KP, and 21.4% for poplar KP. The solid residuals from enzymatic treatment contained about 93.3% and 90.7% of the lignin originally presented in the spruce KP and poplar KP respectively. The enzymatic treated residual was then subjected to mild acidolysis, which caused the cleavage of lignin-carbohydrate linkages. The resulting Ground Enzymatic/Acidolysis KraftLignin (GEA-KL) is of significantly higher yield than our previous two-step (enzymatic/acidolysis) residual kraft lignin (EA-KL). The improved method offers kraft lignin preparations in higher yield and purity than any other known method with minimal work up and solvent requirements. DFRC/quantitative P NMR protocol and quantitative DEPT edited C RMR were used for characterizing of RKLs.

  10. Genetically Engineered Wine Yeast Produces a High Concentration of l-Lactic Acid of Extremely High Optical Purity

    OpenAIRE

    Saitoh, Satoshi; Ishida, Nobuhiro; Onishi, Toru; Tokuhiro, Kenro; Nagamori, Eiji; Kitamoto, Katsuhiko; Takahashi, Haruo

    2005-01-01

    For mass production of lactic acid, we newly constructed a transgenic wine yeast strain that included six copies of the bovine l-lactate dehydrogenase gene on the genome. On fermentation in inexpensive cane juice-based medium, l-lactate production of this recombinant reached 122 g/liter and the optical purity was 99.9% or higher.

  11. Towards a single step process to create high purity gold structures by electron beam induced deposition at room temperature

    Science.gov (United States)

    Mansilla, C.; Mehendale, S.; Mulders, J. J. L.; Trompenaars, P. H. F.

    2016-10-01

    Highly pure metallic structures can be deposited by electron beam induced deposition and they have many important applications in different fields. The organo-metallic precursor is decomposed and deposited under the electron beam, and typically it is purified with post-irradiation in presence of O2. However, this approach limits the purification to the surface of the deposit. Therefore, ‘in situ’ purification during deposition using simultaneous flows of both O2 and precursor in parallel with two gas injector needles has been tested and verified. To simplify the practical arrangements, a special concentric nozzle has been designed allowing deposition and purification performed together in a single step. With this new device metallic structures with high purity can be obtained more easily, while there is no limit on the height of the structures within a practical time frame. In this work, we summarize the first results obtained for ‘in situ’ Au purification using this concentric nozzle, which is described in more detail, including flow simulations. The operational parameter space is explored in order to optimize the shape as well as the purity of the deposits, which are evaluated through scanning electron microscope and energy dispersive x-ray spectroscopy measurements, respectively. The observed variations are interpreted in relation to other variables, such as the deposition yield. The resistivity of purified lines is also measured, and the influence of additional post treatments as a last purification step is studied.

  12. Tensile properties and interfacial bonding of multi-layered, high-purity titanium strips fabricated by ARB process.

    Science.gov (United States)

    Ghafari-Gousheh, Soroush; Nedjad, Syamak Hossein; Khalil-Allafi, Jafar

    2015-11-01

    Severe plastic deformation (SPD) processing has shown very effective in promotion of mechanical properties of metals and alloys. In this study, the results of investigating mechanical properties and also inter-layer bond performance of accumulative roll bonded high purity titanium (HP-Ti) strips are presented. High purity titanium plates were severely deformed by use of a combination of cold rolling (CR) to a thickness reduction of approximately 87% and then accumulative roll bonding (ARB) for three cycles (N=3) at ambient temperature. Optical and scanning electron microscopy, tensile testing, and hardness measurements were conducted. The ARB strips exhibited lower tensile strength and ductility in comparison to cold rolled one which can basically be attributed to the poor function of the latest bonds established in the centerlines of the strips. Fractographic examinations revealed the interfacial de-bonding along the centerline between the layers having undergone roll bonding for just one cycle. It was while the interfaces having experienced roll bonding for more cycles showed much higher resistance against delaminating. PMID:26253205

  13. Determination of trace elements in high purity alumina powder by helium enhanced direct current glow discharge mass spectrometry

    Science.gov (United States)

    Jung, Sehoon; Kim, Sunhye; Hinrichs, Joachim

    2016-08-01

    Trace impurities in high purity alumina powder were determined by fast flow direct current glow discharge mass spectrometry (GD-MS). The non-conductive samples were prepared with high purity graphite powder and used as a sample binder and as a secondary cathode. To improve the sensitivity of the GD-MS analysis, helium was introduced as an additional glow discharge gas to argon plasma. The quantification results of the GD-MS measurement were calculated by external calibration with matrix matched certified reference materials. The GD-MS results for the determination of Na, Mg, Si, Ca, Ti, V, Cr, Fe, Cu, Zn and Ga in the alumina samples agreed well with the certified values of a reference material and the results of chemical analysis using wet sample digestion with inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The GD-MS analysis is a rapid analysis technique to determine trace elements in non-conductive alumina to below mg·kg- 1 levels.

  14. All electrochemical fabrication of a bilayer membrane composed of nanotubular photocatalyst and palladium toward high-purity hydrogen production

    Science.gov (United States)

    Hattori, Masashi; Noda, Kei

    2015-12-01

    We developed an all-electrochemical technique for fabricating a bilayer structure of a titanium dioxide (TiO2) nanotube array (TNA) and a palladium film (TNA/Pd membrane), which works for photocatalytic high-purity hydrogen production. Electroless plating was used for depositing the Pd film on the TNA surface prepared by anodizing a titanium foil. A 3-μm-thick TNA/Pd membrane without any pinholes in a 1.5-cm-diameter area was fabricated by transferring a 1-μm-thick TNA onto an electroless-plated 2-μm-thick Pd film with a mechanical peel-off process. This ultrathin membrane with sufficient mechanical robustness showed photocatalytic H2 production via methanol reforming under ultraviolet illumination on the TNA side, immediately followed by the purification of the generated H2 gas through the Pd layer. The hydrogen production rate and the apparent quantum yield for high-purity H2 production from methanol/water mixture with the TNA/Pd membrane were also examined. This work suggests that palladium electroless plating is more suitable and practical for preparing a well-organized TNA/Pd heterointerface than palladium sputter deposition.

  15. 57Fe hyperfine interaction parameters and selected magnetic properties of high purity MFe12O19 (M = Sr, Ba)

    International Nuclear Information System (INIS)

    Much of the confusion regarding the 57Fe Moessbauer spectroscopic hyperfine parameters of SrFe12O19 and BaFe12O19 at 300 K has been removed by means of an interlaboratory investigation of well-characterized samples prepared from high purity starting materials. In contrast to previous investigations, the contributions of each of the five Fe sublattices to the Moessbauer spectrum are discernible at 300 K and five components are necessary for an adequate fit of the data. The relative magnitudes of the hyperfine fields, Hn, and isomer shifts, δ, are as follows: for SrFe12O19 and BaFe12O19: Hn(2b)n(12k)n(4f1)n(2a)n(4f2), for SrFe12O19 δ(4f1)≤δ(2b)2), and for BaFe12O19 δ(2b)1)2)<δ(2a). The above assignment is based on considerations of both magnetic and crystal/chemical structures. The high purity starting materials seem to have appreciable influences on both hyperfine interaction parameters and bulk magnetic properties as observed by others for spinel and garnet ferrites. (orig.)

  16. Thermal behavior of Ni (99.967% and 99.5% purity) deformed to an ultra-high strain by high pressure torsion

    DEFF Research Database (Denmark)

    Zhang, H.W.; Huang, Xiaoxu; Pippan, R.;

    2010-01-01

    Polycrystalline Ni of two purities (99.967% (4N) and 99.5% (2N)) was deformed to an ultra-high strain of εvM = 100 (εvM, von Mises strain) by high pressure torsion at room temperature. The 4N and 2N samples at this strain are nanostructured with an average boundary spacing of 100 nm, a high density...

  17. High Color-Purity Green, Orange, and Red Light-Emitting Didoes Based on Chemically Functionalized Graphene Quantum Dots

    Science.gov (United States)

    Kwon, Woosung; Kim, Young-Hoon; Kim, Ji-Hee; Lee, Taehyung; Do, Sungan; Park, Yoonsang; Jeong, Mun Seok; Lee, Tae-Woo; Rhee, Shi-Woo

    2016-04-01

    Chemically derived graphene quantum dots (GQDs) to date have showed very broad emission linewidth due to many kinds of chemical bondings with different energy levels, which significantly degrades the color purity and color tunability. Here, we show that use of aniline derivatives to chemically functionalize GQDs generates new extrinsic energy levels that lead to photoluminescence of very narrow linewidths. We use transient absorption and time-resolved photoluminescence spectroscopies to study the electronic structures and related electronic transitions of our GQDs, which reveals that their underlying carrier dynamics is strongly related to the chemical properties of aniline derivatives. Using these functionalized GQDs as lumophores, we fabricate light-emitting didoes (LEDs) that exhibit green, orange, and red electroluminescence that has high color purity. The maximum current efficiency of 3.47 cd A‑1 and external quantum efficiency of 1.28% are recorded with our LEDs; these are the highest values ever reported for LEDs based on carbon-nanoparticle phosphors. This functionalization of GQDs with aniline derivatives represents a new method to fabricate LEDs that produce natural color.

  18. Application of a Barrier Filter at a High Purity Synthetic Graphite Plant, CRADA 99-F035, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2000-08-31

    Superior Graphite Company and the US Department of Energy have entered into a Cooperative Research and Development Agreement (CRADA) to study the application of ceramic barrier filters at its Hopkinsville, Kentucky graphite plant. Superior Graphite Company is a worldwide leader in the application of advanced thermal processing technology to produce high purity graphite and carbons. The objective of the CRADA is to determine the technical and economic feasibility of incorporating the use of high-temperature filters to improve the performance of the offgas treatment system. A conceptual design was developed incorporating the ceramic filters into the offgas treatment system to be used for the development of a capital cost estimate and economic feasibility assessment of this technology for improving particulate removal. This CRADA is a joint effort of Superior Graphite Company, Parsons Infrastructure and Technology Group, and the National Energy Technology Laboratory (NETL) of the US Department of Energy (DOE).

  19. Trace analysis measurements in high-purity aluminium by means of radiochemical neutron and proton activation analysis

    International Nuclear Information System (INIS)

    The aim of the study consisted in the development of efficient radiochemical composite processes and activation methods for the multi-element determination of traces within the lower ng range in high-purity aluminium. More than 50 elements were determined with the help of activation with reactor neutrons; the selective separation of matrix activity (adsorption with hydrated antimony pentoxide) led to a noticeable improvement of detectability, as compared with instrumental neutron activation analysis. Further improvements were achieved with the help of radiochemical group separations in ion exchangers or with the help of the selective separation of the pure beta-emitting elements. Over 20 elements up to high atomic numbers were determined by means of activating 13 MeV protons and 23 Me protons. In this connection, improvements of the detection limit by as a factor of 10 were achieved with radiochemical separation techniques, as compared with pure instrumental proton activation analysis. (RB)

  20. Mapping bare soil in South West Wales, UK, using high resolution colour infra-red aerial photography for water quality and flood risk management applications

    Science.gov (United States)

    Sykes, Helena; Neale, Simon; Coe, Sarah

    2016-04-01

    Natural Resources Wales is a UK government body responsible for environmental regulation, among other areas. River walks in Water Framework Directive (WFD) priority catchments in South West Wales, UK, identified soil entering water courses due to poaching and bank erosion, leading to deterioration in the water quality and jeopardising the water quality meeting legal minimum standards. Bare soil has also been shown to cause quicker and higher hydrograph peaks in rural catchments than if those areas were vegetated, which can lead to flooding of domestic properties during peak storm flows. The aim was to target farm visits by operational staff to advise on practices likely to improve water quality and to identify areas where soft engineering solutions such as revegetation could alleviate flood risk in rural areas. High resolution colour-infrared aerial photography, 25cm in the three colour bands and 50cm in the near infrared band, was used to map bare soil in seven catchments using supervised classification of a five band stack including the Normalised Difference Vegetation Index (NDVI). Mapping was combined with agricultural land use and field boundary data to filter out arable fields, which are supposed to bare soil for part of their cycle, and was very successful when compared to ground truthing, with the exception of silage fields which contained sparse, no or unproductive vegetation at the time the imagery was acquired leading to spectral similarity to bare soil. A raindrop trace model was used to show the path sediment from bare soil areas would take when moving through the catchment to a watercourse, with hedgerows inserted as barriers following our observations from ground truthing. The findings have been used to help farmers gain funding for improvements such as fencing to keep animals away from vulnerable river banks. These efficient and automated methods can be rolled out to more catchments in Wales and updated using aerial imagery acquired more recently to

  1. The Influence Of Dead Layer Effect On The Characteristics Of The High Purity Germanium P-Type Detector

    International Nuclear Information System (INIS)

    The present work aims at reviewing the studies of the influence of dead layer effect on the characteristics of a high purity germanium (HPGe) p-type detector, obtained by the author and his colleagues in the recent years. The object for study was the HPGe GC1518 detector-based gamma spectrometer of the Center for Nuclear Techniques, Ho Chi Minh City. The studying problems were: The modeling of an HPGe detector-based gamma spectrometer with using the MCNP code; the method of determining the thickness of dead layer by experimental measurements of gamma spectra and the calculations using MCNP code; the influence of material parameters and dead layer on detector efficiency; the increase of dead layer thickness over the operating time of the GC1518 detector; the influence of dead layer thickness increase on the decrease of detector efficiency; the dead layer effect for the gamma spectra measured in the GC1518 detector. (author)

  2. Performance of a compact multi-crystal high-purity germanium detector array for measuring coincident gamma-ray emissions

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Chris; Daigle, Stephen; Buckner, Matt [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Erikson, Luke E.; Runkle, Robert C. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Stave, Sean C., E-mail: Sean.Stave@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Champagne, Arthur E.; Cooper, Andrew; Downen, Lori [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Glasgow, Brian D. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Kelly, Keegan; Sallaska, Anne [University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States)

    2015-05-21

    The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the {sup 14}N(p,γ){sup 15}O{sup ⁎} reaction for several transition energies at an effective center-of-mass energy of 163 keV. Owing to the granular nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within their uncertainties with the past measurements. Details of the analysis and detector performance are presented.

  3. Phase transformations of high-purity PbI2 nanoparticles synthesized from lead-acid accumulator anodes

    Science.gov (United States)

    Malevu, T. D.; Ocaya, R. O.; Tshabalala, K. G.

    2016-09-01

    High-purity hexagonal lead iodide nanoparticles have been synthesized from a depleted sealed lead acid battery anode. The synthesized product was found to consist of the rare 6R polytype form of PbI2 that is thought to have good potential in photovoltaic applications. We investigate the effects of annealing time and post-melting temperature on the structure and optical properties using 1.5418 Å CuKα radiation. Photoluminescence measurements were done under 150 W/221 nm wavelength xenon excitation. Phase transformation was observed through XRD peaks when annealing time increased from 0.5-5 h. The nanoparticle grain size and inter-planar distance appeared to be independent of annealing time. PL measurements show three broad peaks in a range of 400 nm to 700 nm that are attributed to excitonic, donor-acceptor pair and luminescence bands from the deep levels.

  4. Optical injection locking of monolithically integrated photonic source for generation of high purity signals above 100 GHz.

    Science.gov (United States)

    Balakier, Katarzyna; Fice, Martyn J; van Dijk, Frederic; Kervella, Gael; Carpintero, Guillermo; Seeds, Alwyn J; Renaud, Cyril C

    2014-12-01

    A monolithically integrated photonic source for tuneable mm-wave signal generation has been fabricated. The source consists of 14 active components, i.e. semiconductor lasers, amplifiers and photodetectors, all integrated on a 3 mm(2) InP chip. Heterodyne signals in the range between 85 GHz and 120 GHz with up to -10 dBm output power have been successfully generated. By optically injection locking the integrated lasers to an external optical comb source, high-spectral-purity signals at frequencies >100 GHz have been generated, with phase noise spectral density below -90 dBc/Hz being achieved at offsets from the carrier greater than 10 kHz. PMID:25606875

  5. Effect of alumina on sintering behavior and electrical conductivity of high-purity yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    The sintering behavior and electrical conductivity of high-purity 8-mol% Y2O3-stabilized ZrO2 (8YSZ) with Al2O3 additions were investigated. The addition of 1 wt% Al2O3 to 8YSZ provided dense, sintered samples with 94% relative density at 1,400 C without a holding time. Addition of 1 wt% SiO2 enhanced the sinterability of 8YSZ. Na2O addition of 0.1 wt% remarkably lowered it. Electrical conductivity at 1,000 C in air increased slightly with increased Al2O3 content up to 1 wt% and then monotonously decreased. 8YSZ with 1 wt% Al2O3 showed the maximum conductivity of 0.16 S/cm at 1,000 C

  6. Near-Infrared Femtosecond Laser Induced Defect Formation in High Purity Silica Below the Optical Breakdown Threshold

    Institute of Scientific and Technical Information of China (English)

    周秦岭; 刘丽英; 徐雷; 王文澄; 朱从善; 干福熹

    2003-01-01

    Optical absorption, electron spin resonance and photoluminescence spectra were used to study the defect formation in high purity fused silica induced by a focused infrared femtosecond laser with the input intensity below damage threshold. Si E' centres were formed in the silica. The number of Si E' centre was found increasing linearly with power density of the fs laser, deviated from the increment photo-induced free carrier density. We concluded that the colour centres were formed at the defect sites that were newly generated by radiolysis of silica tetrahedral network and displacement of oxygen between two silicon atoms. Material structure is already modified even though the irradiation fs laser power was well below the damage threshold.

  7. 高纯镓制备技术的研究进展%Study Status of Preparing Method for High-purity Gallium

    Institute of Scientific and Technical Information of China (English)

    厉英; 曾杰; 闫晨; 刘杰

    2013-01-01

    High-purity gallium is mainly used in wireless communication and photoelectric semiconductor field in the form of GaAs, GaP and GaN. With the rapid development of the market on 3G smartphone and LED, the de mand for high-purity gallium increases steadily, so it is essential to enhance the research and production of high-purity gallium. The related methods for preparing high-purity gallium are reviewed, the advantages and disadvantages of the various methods are compared. It is pointed out that the combined process is an efficient and feasible method to produ cing high-purity gallium.%高纯镓主要以砷化镓、磷化镓、氮化镓的形式应用于无线通讯和光电半导体领域;随着3G智能手机、LED市场的快速发展,对高纯镓产品需求越来越大,因此应加强对高纯镓的研制和生产.总结了高纯镓的相关制备方法,分析比较了各种方法的优缺点,指出联合法是生产高纯镓的高效可行的方法.

  8. High-purity 60GHz band millimeter-wave generation based on optically injected semiconductor laser under subharmonic microwave modulation.

    Science.gov (United States)

    Fan, Li; Xia, Guangqiong; Chen, Jianjun; Tang, Xi; Liang, Qing; Wu, Zhengmao

    2016-08-01

    Based on an optically injected semiconductor laser (OISL) operating at period-one (P1) nonlinear dynamical state, high-purity millimeter-wave generation at 60 GHz band is experimentally demonstrated via 1/4 and 1/9 subharmonic microwave modulation (the order of subharmonic is with respect to the frequency fc of the acquired 60 GHz band millimeter-wave but not the fundamental frequency f0 of P1 oscillation). Optical injection is firstly used to drive a semiconductor laser into P1 state. For the OISL operates at P1 state with a fundamental frequency f0 = 49.43 GHz, by introducing 1/4 subharmonic modulation with a modulation frequency of fm = 15.32 GHz, a 60 GHz band millimeter-wave with central frequency fc = 61.28 GHz ( = 4fm) is experimentally generated, whose linewidth is below 1.6 kHz and SSB phase noise at offset frequency 10 kHz is about -96 dBc/Hz. For fm is varied between 13.58 GHz and 16.49 GHz, fc can be tuned from 54.32 GHz to 65.96 GHz under matched modulation power Pm. Moreover, for the OISL operates at P1 state with f0 = 45.02 GHz, a higher order subharmonic modulation (1/9) is introduced into the OISL for obtaining high-purity 60 GHz band microwave signal. With (fm, Pm) = (7.23 GHz, 13.00 dBm), a microwave signal at 65.07 GHz ( = 9fm) with a linewidth below 1.6 kHz and a SSB phase noise less than -98 dBc/Hz is experimentally generated. Also, the central frequency fc can be tuned in a certain range through adjusting fm and selecting matched Pm. PMID:27505789

  9. 高纯六氟化钨制备工艺研究%Preparation Technology of High Purity Tungsten Hexafluoride

    Institute of Scientific and Technical Information of China (English)

    陈志刚; 陈财华; 冯振雷

    2014-01-01

    介绍了利用氟气与钨粉为原料制备高纯六氟化钨的工艺方法和设备体系。其过程是利用电解槽电解氟氢化钾制取氟气,并采用氟化钠吸附配合深冷工艺纯化氟气,净化后的氟气与固定床里的钨粉在一定温度条件下反应合成初级六氟化钨,通过低温冷凝回收,收集的初级六氟化钨经过固化后抽真空排轻等方法进行初步提纯,然后将初步提纯的产品蒸馏至填料式精馏塔内进行深度提纯,经过多步提纯后的成品六氟化钨纯度可达99.999%以上。%This paper introduces the processing and equipment system for high-purity tungsten hexafluoride using fluorine gas and tungsten powder as raw materials. Electrolytic cell is applied to prepare fluorine gas by electrolyzing the potassium bifluoride. Sodium fluoride adsorption with cryogenic mixture is used to purify the fluorine gas. Purified fluorine gas reacts with tungsten powder to synthesize the impure tungsten hexafluoride in the fixed bed reactor at a certain temperature. The impure tungsten hexafluoride is obtained by low-temperature condensation. Curing and vacuuming technologies are performed on impure tungsten hexafluoride use to remove the volatile impurity. Filler type distillation column is utilized to further purify by monitoring the distillation products intermittently to prevent unqualified products collection. The results show that the purity of tungsten hexafluoride reaches 99.999%.

  10. Quantification of the microstructures of high purity nickel subjected to dynamic plastic deformation

    DEFF Research Database (Denmark)

    Luo, Z.P.; Zhang, H.W.; Hansen, Niels;

    2012-01-01

    A quantitative microstructural analysis is presented for pure polycrystalline nickel processed by means of dynamic plastic deformation at high strain rates (102–103 s−1) to strains from 0.3 to 2.9. This analysis covers a number of structural parameters, such as the spacing between and the misorie......A quantitative microstructural analysis is presented for pure polycrystalline nickel processed by means of dynamic plastic deformation at high strain rates (102–103 s−1) to strains from 0.3 to 2.9. This analysis covers a number of structural parameters, such as the spacing between...... and high angle boundaries. Shear bands and twins have not been observed. In order to underpin the structural analysis, the mechanical properties as a function of strain have been determined by tensile and hardness tests. The flow stress is 850 MPa, showing that high strain rate deformation has potential...

  11. High-purity rare-earth metals: preparation, properties, and application

    Institute of Scientific and Technical Information of China (English)

    Kol'chugina; N.; B.; Burkhanov; G.; S.; Chistyakov; O.; D.; Burkhanov; Yu.; S.

    2005-01-01

    In recent years, the ever-growing interest of investigators to the study of rare-earth metals REM) is observed owing to unique properties of the metals and potential uses in electronics, laser technology, space technology, medicine, and many other high-technology applications.……

  12. High-purity rare-earth metals: preparation, properties, and application

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ In recent years, the ever-growing interest of investigators to the study of rare-earth metals REM) is observed owing to unique properties of the metals and potential uses in electronics, laser technology, space technology, medicine, and many other high-technology applications.

  13. Radiation detectors fabricated on high-purity GaAs epitaxial materials

    Science.gov (United States)

    Wu, X.; Kostamo, P.; Gädda, A.; Nenonen, S.; Riekkinen, T.; Härkönen, J.; Salonen, J.; Andersson, H.; Zhilyaev, Y.; Fedorov, L.; Eränen, S.; Mattila, M.; Lipsanen, H.; Prunnila, M.; Kalliopuska, J.; Oja, A.

    2014-12-01

    Epitaxial GaAs material shows a great potential in X-ray spectroscopy and radiography applications due to its high absorption efficiency and low defect density. Fabrication of pixel radiation detectors from high-purtity epitaxial GaAs has been developed further. The process is based on mesa etching for pixellisation and sputtering for metallization. The leakage currents of processed pad detectors are below 10 nA/cm2 at a reverse bias of 100 V and decrease exponentially with the temperature. Measurement with transient current technique (TCT) shows that electrons have a trapping time of 8 ns. Good spectroscopic result were obtained from both a pad detector and a hybridized Medipix GaAs detector.

  14. State-of-the-art in analytical characterization of high purity solid samples by different spectroscopic methods

    Indian Academy of Sciences (India)

    S S Grazhulene

    2005-07-01

    Facilities and some results of several spectroscopic methods which have potential applications in the field of analysis of solid high purity substances and which have been elaborated in Russia, will be discussed in this paper. Laser nondispersive atomic fluorescence method with glow discharge cathode sputtering atomiser, may be used for trace element determination as well as a tool for the investigation of technological processes, viz. deposition of thin films. Investigations on reduction of a background level in the new hollow cathode ion source for mass-spectrometry have been carried out. Laser mass spectrometry with tandem laser mass reflectron is successfully designed and applied for gaseous impurities determination in high pure silicon with limit of detection of 10-3–10-5 ppm wt. Several results of the layer-by-layer and bulk trace analysis of solids by high resolution mass spectrometry with radio frequency powered glow discharge ion source with the limits of detection at 10-1–10-3 ppm wt will be presented here. The traditional arc and spark emission technique still finds considerable use. One of the examples considered in the paper is the analysis of metalfullerenes. To overcome the calibration problem the fluorination process inside the electrode crater using zinc fluoride has been investigated.

  15. Positive corona discharge ion source with IMS/MS to detect impurities in high purity Nitrogen

    OpenAIRE

    Sabo, M.; Klas, M.; Wang, H.; Huang, C.; Chu, Y; Matejčík, Š.

    2011-01-01

    Abstract We have applied the Ion Mobility Spectrometry/Mass Spectrometry (IMS/MS) and the Atmospheric Pressure Chemical Ionisation/Mass Spectrometry (APCI/MS) techniques to study the formation of the ions in the positive corona discharge (CD) in highly purified nitrogen with impurities at 100 ppt level. The main products observed were H3O+(H2O)n ions (reduced ion mobility of 2.15 cm2?V-1?s-1). Additionally, we have observed ions with reduced mobilities 2.42 ...

  16. The control of purity and stoichiometry of compound semiconductors by high vapor pressure transport

    Science.gov (United States)

    Bachmann, Klaus J.; Ito, Kazufumi; Scroggs, Jeffery S.; Tran, Hien T.

    1995-01-01

    In this report we summarize the results of a three year research program on high pressure vapor transport (HPVT) of compound semiconductors. Most of our work focused onto pnictides, in particular ZnGeP2, as a model system. Access to single crystals of well controlled composition of this material is desired for advancing the understanding and control of its point defect chemistry in the contest of remote, real-time sensing of trace impurities, e.g., greenhouse gases, in the atmosphere by ZnGeP2 optical parametric oscillators (OPO's).

  17. thesis of high-purity carbon nanotubes over alumina and silica supported bimetallic catalysts

    Directory of Open Access Journals (Sweden)

    Sanja Ratković

    2009-10-01

    Full Text Available Carbon nanotubes (CNTs were synthesized by a catalytic chemical vapor deposition method (CCVD of ethylene over alumina and silica supported bimetallic catalysts based on Fe, Co and Ni. The catalysts were prepared by a precipitation method, calcined at 600 °C and in situ reduced in hydrogen flow at 700 °C. The CNTs growth was carried out by a flow the mixture of C2H4 and nitrogen over the catalyst powder in a horizontal oven. The structure and morphology of as-synthesized CNTs were characterized using SEM. The as-synthesized nanotubes were purified by acid and basic treatments in order to remove impurities such as amorphous carbon, graphite nanoparticles and metal catalysts. XRD and DTA/TG analyses showed that the amounts of by-products in the purified CNTs samples were reduced significantly. According to the observed results, ethylene is an active carbon source for growing high-density CNTs with high yield but more on alumina-supported catalysts than on their silica- supported counterparts. The last might be explained by SMSI formed in the case of alumina-supported catalysts, resulting in higher active phase dispersion.

  18. Cryogenic Implosion Performance Using High-Purity Deuterium-Tritium Fuel

    Science.gov (United States)

    Sangster, T. C.; Goncharov, V. N.; Radha, P. B.; Earley, R.; Epstein, R.; Forrest, C. J.; Froula, D. H.; Glebov, V. Yu.; Hu, S. X.; Igumenshchev, I. V.; Marshall, F. J.; McKenty, P. W.; Shmayda, W. T.; Shoup, M. J., III; Michel, D. T.; Stoeckl, C.; Seka, W.; Frenje, J. A.; Gatu Johnson, M.

    2014-10-01

    Demonstrating hydrodynamic equivalence between symmetric implosions on OMEGA and National Ignition Facility ignition designs will require a number of facility enhancements that include dynamic bandwidth reduction, a set of higher-order super-Gaussian phase plates, high-spatial-resolution gated-core imaging, high-bandwidth neutron burnwidth measurements, improved power balance, and contaminant-free deuterium-tritium (DT) fuel. The historic DT fuel supply was contaminated with ~6 atm% of 1H, leading to significant fractionation of the fuel during the layering process (the triple points of H:D and H:T are significantly colder than DD, DT, and TT). The fractionation leads to a drop in the potential yield because the D and T number densities are lower in the void than they would be with a pure-DT mixture). An isotope separation system has been developed to remove the 1H from the DT fuel supply. This talk will discuss the first results with the purified fuel, conclusions from recent implosions to test cross-beam energy transfer mitigation, and the status of the remaining facility enhancements. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. High purity microfluidic sorting and analysis of circulating tumor cells: towards routine mutation detection.

    Science.gov (United States)

    Autebert, Julien; Coudert, Benoit; Champ, Jérôme; Saias, Laure; Guneri, Ezgi Tulukcuoglu; Lebofsky, Ronald; Bidard, François-Clément; Pierga, Jean-Yves; Farace, Françoise; Descroix, Stéphanie; Malaquin, Laurent; Viovy, Jean-Louis

    2015-05-01

    A new generation of the Ephesia cell capture technology optimized for CTC capture and genetic analysis is presented, characterized in depth and compared with the CellSearch system as a reference. This technology uses magnetic particles bearing tumour-cell specific EpCAM antibodies, self-assembled in a regular array in a microfluidic flow cell. 48,000 high aspect-ratio columns are generated using a magnetic field in a high throughput (>3 ml h(-1)) device and act as sieves to specifically capture the cells of interest through antibody-antigen interactions. Using this device optimized for CTC capture and analysis, we demonstrated the capture of epithelial cells with capture efficiency above 90% for concentrations as low as a few cells per ml. We showed the high specificity of capture with only 0.26% of non-epithelial cells captured for concentrations above 10 million cells per ml. We investigated the capture behavior of cells in the device, and correlated the cell attachment rate with the EpCAM expression on the cell membranes for six different cell lines. We developed and characterized a two-step blood processing method to allow for rapid processing of 10 ml blood tubes in less than 4 hours, and showed a capture rate of 70% for as low as 25 cells spiked in 10 ml blood tubes, with less than 100 contaminating hematopoietic cells. Using this device and procedure, we validated our system on patient samples using an automated cell immunostaining procedure and a semi-automated cell counting method. Our device captured CTCs in 75% of metastatic prostate cancer patients and 80% of metastatic breast cancer patients, and showed similar or better results than the CellSearch device in 10 out of 13 samples. Finally, we demonstrated the possibility of detecting cancer-related PIK3CA gene mutation in 20 cells captured in the chip with a good correlation between the cell count and the quantitation value Cq of the post-capture qPCR. PMID:25815443

  20. Muon diffusion and trapping studies in high purity vanadium. [Temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Heffner, R.H.; Brown, J.A.; Hutson, R.L.; Leon, M.; Gauster, W.B.; Carlson, O.N.; Rehbein, D.K.; Fiory, A.T.

    1978-01-01

    The first results of a study of the effects of varying impurity concentration on the temperature dependence of the depolarization rate of positive muons implanted into vanadium are presented. Data are reported for the most highly purified polycrystalline sample yet measured, and the same sample subsequently doped with about 500 ppM oxygen by weight. The data for the pure sample shows a low depolarization rate (< .15 ..mu..sec/sup -1/) at all temperatures measured, showing a broad minimum centered at approx. 35 K, followed by a sharp peak near 90 K and a rapid drop to negligible values at 200 K. The data are contrasted with previously published data on less pure samples, and call into question previous interpretations of the behavior of the ..mu../sup +/ at low temperatures in impure vanadium as one-phonon-assisted tunneling. 6 references.

  1. High Purity Germanium Gamma-PHA Assay of Uranium Storage Pigs for 321-M Facility

    Energy Technology Data Exchange (ETDEWEB)

    Dewberry, R.A.

    2001-09-18

    The Analytical Development Section of SRTC was requested by the Facilities Disposition Division (FDD) to determine the holdup of enriched uranium in the 321-M facility as part of an overall deactivation project of the facility. The 321-M facility was used to fabricate enriched uranium fuel assemblies, lithium-aluminum target tubes, neptunium assemblies, and miscellaneous components for the production reactors. The facility also includes the 324-M storage building and the passageway connecting it to 321-M. The results of the holdup assays are essential for determining compliance with the Solid Waste's Waste Acceptance Criteria, Material Control and Accountability, and to meet criticality safety controls. This report describes and documents the use of a portable HPGe detector and EG and G Dart system that contains a high voltage power supply, signal processing electronics, a personal computer with Gamma-Vision software, and space to store and manipulate multiple 4096-channel g-ray spectra to assay for 235U content in 268 uranium shipping and storage pigs. This report includes a description of three efficiency calibration configurations and also the results of the assay. A description of the quality control checks is included as well.

  2. Application of radiochemistry to the preparation of high-purity silicon

    International Nuclear Information System (INIS)

    Radiochemical studies on the preparation of highly pure silicon for semiconductor use provided various useful information and tools for development of the process. The behaviour of phosphorus impurity during the purification steps of recrystallization and zone refining was followed by using radioactive phosphorus as tracer. The results showed that in each step, hydrolysed products suspended in the silicon tetraiodide played an important role in removing not only phosphorus but also other impurity elements. Activation analysis was applied to the determination of the arsenic concentration throughout the process and it was indicated that this could be reduced to the order of 10-3 ppm after fractional distillation. It was also indicated, by neutron activation analysis, that elemental silicon, after thermal decomposition of the iodide, usually contained several ppm iodine, but its concentration could be reduced by one order of magnitude by a simple fusion. The absorption of soft γ-rays has been applied to the determination of iodine concentration in the iodination gas stream and it has been found that the principle could be applied to the automatic control of the iodination reaction with further development of the technique. (author)

  3. Expression and purification of bioactive high-purity human midkine in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Zhong-hui ZHANG; Li-juan DU; Di XIANG; Shun-ying ZHU; Ming-yuan WU; Hui-li LU; Yan YU; Wei HAN

    2009-01-01

    Midkine is a heparin-binding growth factor,which plays important roles in the regulation of cell growth and differentiation.The non-tagged recombinant human midkine (rhMK) is therefore required to facilitate its functional studies of this important growth factor.In the present work,rhMK was expressed in Escherichia coli (E.coli) BL21 (DE3).The expression of midkine was efficiently induced by isopropyl-β-D-thiogalactopyranoside (IPTG).After sonication,midkine was recovered in an insoluble form,and was dissolved in guaoidine hydrochloride buffer.Renaturation of the denatured protein was carried out in the defined protein refolding buffer,and the refolded protein was purified using S-Sepharose ion-exchange chromatography.The final preparation of the rhMK was greater than 98% pure as measured by sodium dodecylsulfate-polyacrylamid gel electrophoresis (SDS-PAGE) and reverse phase high performance liquid chromatography (RP-HPLC).The purified rhMK enhanced the proliferation of NIH3T3 cells.

  4. Plastic deformation of high-purity a-titanium: model development and validation using the Taylor cylinder impact test

    Science.gov (United States)

    Chandola, Nitin; Revil-Baudard, Benoit; Cazacu, Oana

    2016-08-01

    Results of an experimental study on the quasi-static and high-rate plastic deformation due to impact of a high-purity, polycrystalline, a-titanium material are presented. To quantify the plastic anisotropy and tension-compression asymmetry of the material, first monotonic uniaxial compression and tension tests were carried out at room temperature under quasi-static conditions. It was found that the material is transversely isotropic and displays strong strength differential effects. To characterize the material's strain rate sensitivity, Split Hopkinson Pressure Bar tests in tension and compression were also conducted. Taylor impact tests were performed for impact velocity of 196 m/s. Plastic deformation extended to 64% of the length of the deformed specimen, with little radial spreading. To model simultaneously the observed anisotropy, strain-rate sensitivity, and tension-compression asymmetry of the material, a three-dimensional constitutive model was developed. Key in the formulation is a macroscopic yield function [1] that incorporates the specificities of the plastic flow, namely the combined effects of anisotropy and tension-compression asymmetry. Comparison between model predictions and data show the capabilities of the model to describe with accuracy the plastic behavior of the a-Ti material for both quasi-static and dynamic loadings, in particular, a very good agreement was obtained between the simulated and experimental post-test Taylor specimen geometries.

  5. Cyclotron production of high-purity 123I for medical applications via the 127I(p,5n)123Xe → 123I nuclear reaction

    International Nuclear Information System (INIS)

    The use of iodine-123 in nuclear medicine procedures is well documented in the scientific literature. Also, several methods for its production based on accelerator techniques have been described. Indirectly made 123I via the 127I(p,5n)123Xe → 123I reaction produces 123I of > 99.9% radionuclidic purity, with only 125I (123I production were developed at the University of California at Davis, where since 1974 the 76-in. isochronous cyclotron of the Crocker Nuclear Laboratory has been used for routine biweekly production of high-purity no-carrier-added 123I

  6. SYNTHESIS OF HIGH PURITY TiO2 NANOPARTICLES FROM Ti(SO4)2 IN PRESENCE OF EDTA AS COMPLEXING AGENT

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yu Guo; Youzhi Liu

    2005-01-01

    TiO2 nanoparticles were synthesized by a homogeneous controlled precipitation method using industrial titanium sulfate (Ti(SO4)2). The obtained powders were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and ICP plasma spectrometer. EDTA was used as complexing agent to improve the purity and the formation of TiO2 nanoparticles. Experimental results indicated that the high-purity TiO2 nanoparticles were 20 nm in mean size and nearly monodispersed.

  7. Corrosion of high purity copper as engineering barrier in deep geological repositories

    International Nuclear Information System (INIS)

    Pure copper with oxygen content below 5 ppm (to minimize segregation at grain boundaries) and doped with phosphorus (to increase creep resistance) is the chosen material for the corrosion-resistant barrier of the High Level Radioactive 2 Wastecontainers in the Swedish and Finnish repository models. These models include the construction of the repository below the water table, which is a reducing environment in which copper has excellent resistance to general and localized corrosion in aqueous electrolytes. The aim of this work is contribute to determine the durability of the material, given that deep geological repositories of HLW are designed to ensure the protection of the environment for periods of hundreds of thousands years. As a first step in a more general analysis the effects of chloride, one of the main aggressive species of corrosion, are evaluated. To this purpose corrosion potential was determined and anodic polarization curves were performed in deaerated solutions varying the chloride concentration between 0.01 and 1M and the temperature between 30 and 90°C. Several electrochemical techniques were used: the evolution of corrosion potential was measured, anodic polarization curves were obtained and electrochemical impedance tests were performed. The analysis was complemented with microscopic observations of the type of corrosive attack, as well as determinations of the eventual corrosion products formed using Energy-Dispersive X-ray Analysis (EDS). Results show that the corrosion potential decreases with the increase of temperature and with the increase of chloride concentration. A correlation of the corrosion potential as a function of temperature and chloride concentration was obtained, with the purpose of making predictions in variable conditions.The current density increases both with temperature and with chloride concentration. A pitting potential is observed in certain conditions. (author)

  8. A Process Concept for High-Purity Production of Amines by Transaminase-Catalyzed Asymmetric Synthesis: Combining Enzyme Cascade and Membrane-Assisted ISPR

    DEFF Research Database (Denmark)

    Börner, Tim; Rehn, Gustav; Grey, Carl;

    2015-01-01

    in situ product removal (ISPR) approach using liquid-membrane extraction together with an enzyme cascade. This ISPR strategy facilitates very high (>98%) product purity with an integrated enrichment step and eliminates product as well as coproduct inhibition. In the presented proof-of-concept alanine...

  9. Migration of grain boundaries and triple junctions in high-purity aluminum during annealing after slight cold rolling

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Wenhong [Institute of Materials, Shanghai University, Shanghai 200072 (China); School of Mechanical Engineering, Shandong University of Technology, Zibo 255049 (China); Wang, Weiguo, E-mail: wang_weiguo@vip.163.com [Institute of Materials, Shanghai University, Shanghai 200072 (China); School of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350118 (China); Fang, Xiaoying [School of Mechanical Engineering, Shandong University of Technology, Zibo 255049 (China); Qin, Congxiang [Institute of Materials, Shanghai University, Shanghai 200072 (China); School of Mechanical Engineering, Shandong University of Technology, Zibo 255049 (China); Xing, Xiaoguang [School of Mechanical Engineering, Shandong University of Technology, Zibo 255049 (China)

    2015-09-15

    Grain orientations and grain boundary migrations near triple junctions in a high purity aluminum were analyzed by electron back scattered diffraction. The results indicate that there are good correlations between the Schmid factors or Taylor factors and the misorientation values of point to original point in grains near the triple junctions in a slightly deformed sample. Grains with higher Schmid factors or lower Taylor factors typically correspond to higher misorientation values near the triple junctions. In a subsequent annealing at 400 °C, both grain boundaries and triple junctions migrate, but the former leave ghost lines. During such migration, a grain boundary grows from the grain with lower Schmid factor (higher Taylor factor) into the grain with higher Schmid factor (lower Taylor factor). Usually, the amount of migration of a grain boundary is considerably greater than that of a triple junction, and the grain boundary becomes more curved after migration. These observations indicate that the triple junctions have drag effects on grain boundary migration. - Highlights: • Polycrystalline aluminum with fine grains about 30 μm were used. • Off-line in situ EBSD was used to identify TJs before and after annealing. • Grains with higher SFs have higher misorientation values near TJs after deformation. • Grain boundaries grow from hard grains into soft grains during annealing. • Triple junctions have drag effects on grain boundaries migration.

  10. Physical simulations and experimental results of 4H-SiC MESFETs on high purity semi-insulating substrates

    Institute of Scientific and Technical Information of China (English)

    Chen Cang; Bai Song; Li Zhe-Yang; Wu Peng; Chen Zheng; Han Pin

    2009-01-01

    In this paper we report on DC and RF simulations and experimental results of 4H-SiC metal semiconductor field effect transistors(MESFETs)on high purity semi-insulating substrates. DC and small-signal measurements are compared with simulations. We design our device process to fabricate n-channel 4H-SiC MESFETs with 100 μm gate periphery. At 30 V drain voltage, the maximum current density is 440 mA/mm and the maximum transconductance is 33 mS/mm. For the continuous wave(CW)at a frequency of 2 GHz, the maximum output power density is measured to be 6.6 W/mm, with a gain of 12 dB and power-added efficiency of 33.7%. The cut-off frequency(f_T)and the maximum frequency(f_(max))are 9 GHz and 24.9 GHz respectively. The simulation results of f_T and f_(max) are 11.4 GHz and 38.6 GHZ respectively.

  11. GEANT4 simulation of photo-peak efficiency of small high purity germanium detectors for nuclear power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Shakeel Ur; Mirza, Sikander M. [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan); Mirza, Nasir M., E-mail: nmm@pieas.edu.p [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan); Siddique, Muhammad Tariq [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)

    2011-01-15

    GEANT4 - based Monte Carlo simulations have been carried out for the determination of photo-peak efficiency of heavily shielded small high purity germanium detector (HPGe) used for monitoring radiation levels in nuclear power plants. The GEANT4 simulated values of HPGe detector efficiency for point as well as for disk sources, for two different values of collimator diameter, have been found in good agreement with the corresponding published results obtained by using the MCNP code. The work has been extended to study the effect of radial displacement of a source relative to a detector on photo-peak efficiency for both point and disk source, and at various values of {gamma}-ray energies. Also the effect of disk source radius on photo-peak efficiency has been studied. Besides the results of different available physics models in GEANT4 have also been compared. The computed values of efficiency for point as well as for disk sources using the Penelope and Livermore physics models have been found correspondingly consistent for various values of {gamma}-ray energies while some differences (e.g., Penelope model yields 6.3% higher values of photo-peak efficiency for E{gamma} = 1.332 MeV, 10 mm collimator diameter) have been observed in the corresponding valued obtained by using the Standard physics model.

  12. Migration of grain boundaries and triple junctions in high-purity aluminum during annealing after slight cold rolling

    International Nuclear Information System (INIS)

    Grain orientations and grain boundary migrations near triple junctions in a high purity aluminum were analyzed by electron back scattered diffraction. The results indicate that there are good correlations between the Schmid factors or Taylor factors and the misorientation values of point to original point in grains near the triple junctions in a slightly deformed sample. Grains with higher Schmid factors or lower Taylor factors typically correspond to higher misorientation values near the triple junctions. In a subsequent annealing at 400 °C, both grain boundaries and triple junctions migrate, but the former leave ghost lines. During such migration, a grain boundary grows from the grain with lower Schmid factor (higher Taylor factor) into the grain with higher Schmid factor (lower Taylor factor). Usually, the amount of migration of a grain boundary is considerably greater than that of a triple junction, and the grain boundary becomes more curved after migration. These observations indicate that the triple junctions have drag effects on grain boundary migration. - Highlights: • Polycrystalline aluminum with fine grains about 30 μm were used. • Off-line in situ EBSD was used to identify TJs before and after annealing. • Grains with higher SFs have higher misorientation values near TJs after deformation. • Grain boundaries grow from hard grains into soft grains during annealing. • Triple junctions have drag effects on grain boundaries migration

  13. Control of the Gas Flow in an Industrial Directional Solidification Furnace for Production of High Purity Multicrystalline Silicon Ingots

    Directory of Open Access Journals (Sweden)

    Lijun Liu

    2015-01-01

    Full Text Available A crucible cover was designed as gas guidance to control the gas flow in an industrial directional solidification furnace for producing high purity multicrystalline silicon. Three cover designs were compared to investigate their effect on impurity transport in the furnace and contamination of the silicon melt. Global simulations of coupled oxygen (O and carbon (C transport were carried out to predict the SiO and CO gases in the furnace as well as the O and C distributions in the silicon melt. Cases with and without chemical reaction on the cover surfaces were investigated. It was found that the cover design has little effect on the O concentration in the silicon melt; however, it significantly influences CO gas transport in the furnace chamber and C contamination in the melt. For covers made of metal or with a coating on their surfaces, an optimal cover design can produce a silicon melt free of C contamination. Even for a graphite cover without a coating, the carbon concentration in the silicon melt can be reduced by one order of magnitude. The simulation results demonstrate a method to control the contamination of C impurities in an industrial directional solidification furnace by crucible cover design.

  14. High Purity and Yield of Boron Nitride Nanotubes Using Amorphous Boron and a Nozzle-Type Reactor

    Directory of Open Access Journals (Sweden)

    Jaewoo Kim

    2014-08-01

    Full Text Available Enhancement of the production yield of boron nitride nanotubes (BNNTs with high purity was achieved using an amorphous boron-based precursor and a nozzle-type reactor. Use of a mixture of amorphous boron and Fe decreases the milling time for the preparation of the precursor for BNNTs synthesis, as well as the Fe impurity contained in the B/Fe interdiffused precursor nanoparticles by using a simple purification process. We also explored a nozzle-type reactor that increased the production yield of BNNTs compared to a conventional flow-through reactor. By using a nozzle-type reactor with amorphous boron-based precursor, the weight of the BNNTs sample after annealing was increased as much as 2.5-times with much less impurities compared to the case for the flow-through reactor with the crystalline boron-based precursor. Under the same experimental conditions, the yield and quantity of BNNTs were estimated as much as ~70% and ~1.15 g/batch for the former, while they are ~54% and 0.78 g/batch for the latter.

  15. Gamma-ray observations of SN 1987A with an array of high-purity germanium detectors

    International Nuclear Information System (INIS)

    A balloon borne gamma-ray spectrometer comprising an array of high-purity n-type germanium (HPGe) detectors having geometric area 119 cm2, resolution 2.5 keV at 1.0 MeV, surrounded by an active NaI (Tl) collimator and Compton suppressing anticoincidence shield nominally 10 cm thick, was flown from Alice Springs, Northern Territory, Australia, on May 29--30, 1987, 96 days after the observed neutrino pulse. The average column depth of residual atmosphere in the direction of SN 1987A at float altitude was 6.3 g cm-2 during the observation. SN 1987A was within the 22-deg full-width-half-maximum (FWHM) field of view for about 3300 s during May 29.9--30.3 UT. No excess gamma rays were observed at energies appropriate to the Ni(56)-Co(56) decay chain or from other lines in the energy region from 0.1 to 3.0 MeV. With 80% of the data analyzed, the 3-sigma upper limit obtained for the 1238-keV line from Co(56) at the instrument resolution (about 3 keV) is 1.3 x 10-3 photons cm-2 s-1

  16. Production of High-purity Magnetite Nanoparticles from a Low-grade Iron Ore via Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Jae; Kil, Dae Sup; Jang, Hee Dong [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Do, Thi May [Korea University of Science and Technology, Daejeon (Korea, Republic of); Cho, Kuk [Pusan National University, Busan (Korea, Republic of)

    2015-02-15

    We produced magnetite nanoparticles (MNPs) and a Mg-rich solution as a nano-adsorbent and a coagulant for water treatment, respectively, using a low-grade iron ore. The ore was leached with aqueous hydrochloric acid and its impurities were removed by solvent extraction of the leachate using tri-n-butyl phosphate as an extractant. The content of Si and Mg, which inhibit the formation of MNPs, was reduced from 10.3 wt% and 15.5 wt% to 28.1 mg/L and < 1.4 mg/L, respectively. Consequently, the Fe content increased from 68.6 wt% to 99.8 wt%. The high-purity Fe{sup 3+} solution recovered was used to prepare 5-15-nm MNPs by coprecipitation. The wastewater produced contained a large amount of Mg{sup 2+} and can be used to precipitate struvite in sewage treatment. This process helps reduce the cost of both sewage and iron-ore-wastewater treatments, as well as in the economic production of the nano-adsorbent.

  17. Inception and propagation of positive streamers in high-purity nitrogen: effects of the voltage rise-rate

    CERN Document Server

    Clevis, T T J; Ebert, U

    2012-01-01

    Controlling streamer morphology is important for numerous applications. Up to now, the effect of the voltage rise rate was only studied across a wide range. Here we show that even slight variations in the voltage rise can have significant effects. We have studied positive streamer discharges in a 16 cm point-plane gap in high-purity nitrogen 6.0, created by 25 kV pulses with a duration of 130 ns. The voltage rise varies by a rise rate from 1.9 kV/ns to 2.7 kV/ns and by the first peak voltage of 22 to 28 kV. A structural link is found between smaller discharges with a larger inception cloud caused by a faster rising voltage. This relation is explained by the greater stability of the inception cloud due to a faster voltage rise, causing a delay in the destabilisation. Time-resolved measurements show that the inception cloud propagates slower than an earlier destabilised, more filamentary discharge. This explains that the discharge with a faster rising voltage pulse ends up to be shorter. Furthermore, the effect...

  18. Thermoluminescence (TL) properties and x-ray diffraction (XRD) analysis of high purity CaSO4:Dy TL material

    International Nuclear Information System (INIS)

    This paper presents the characterization and TL properties of dysprosium (Dy) doped calcium sulfate (CaSO4) TL material produced by co-precipitation technique with 0.5mol% concentration of dopant. The morphology of the produced TL material was studied using scanning electron microscope (SEM) and the micrograph shows that rectangular parallelepiped shaped crystal with the average of 150 μm in length were produced. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectra show that the TL material produced is high purity anhydrite CaSO4 with average crystallite size of 74 nm with orthorhombic crystal system. The TL behavior of produced CaSO4:Dy was studied using a TLD reader after exposure to gamma ray by Co60 source with the doses of 1,5 and 10 Gy. The glow curve shows linear response with glow peak around 230°C which is desired development in the field of radiation dosimetry

  19. Activation analysis for measurements of silicon, phosphorus, alkali metals and other elements in high-purity metals

    International Nuclear Information System (INIS)

    In the present thesis, methods of activation analysis were developed for the determination of the elements silicon, phosphorus, potassium, sodium, i.a. in the high-purity metals vanadium, niobium, tantalum, tungsten, molybdenum and iron. The determination of silicon is based on the activation of samples with reactor neutrons, on a subsequent radiochemical separation of the tracer radionuclide 31Si resulting from the reaction 30Si(n,γ), and on the measurement of β activity with the help of a liquid scintillation measuring desk. Since the tracer radionuclide 31Si almost exclusively emits β rays which are not sufficiently nuclide-specific, silicon was selectively separated from the other sample elements by being distilled as silicon tetrafluoride. The processing of the residue following the separation of silicon permits a complementary gamma-spectroscopic determination of a whole lot of additional elements. Thus, the separation of the nuclide 182Ta with the anion exchanger Dowex 1X8 from HF/H2SO4 medium permits the determination of 22 elements in vanadium, niobium and tantalum. Phosphorus content is determined by activating the samples with rapid neutrons (cyclotrons) via the reaction 31P(n,p)31Si. (orig./MM)

  20. Design, construction, and operation of a laboratory scale reactorfor the production of high-purity, isotopically enriched bulksilicon

    Energy Technology Data Exchange (ETDEWEB)

    Ager III, J.W.; Beeman, J.W.; Hansen, W.L.; Haller, E.E.

    2004-12-20

    The design and operation of a recirculating flow reactor designed to convert isotopically enriched silane to polycrystalline Si with high efficiency and chemical purity is described. The starting material is SiF{sub 4}, which is enriched in the desired isotope by a centrifuge method and subsequently converted to silane. In the reactor, the silane is decomposed to silicon on the surface of a graphite starter rod (3 mm diameter) heated to 700-750 C. Flow and gas composition (0.3-0.5% silane in hydrogen) are chosen to minimize the generation of particles by homogeneous nucleation of silane and to attain uniform deposition along the length of the rod. Growth rates are 5 {micro}m/min, and the conversion efficiency is greater than 95%. A typical run produces 35 gm of polycrystalline Si deposited along a 150 mm length of the rod. After removal of the starter rod, dislocation-free single crystals are formed by the floating zone method. Crystals enriched in all 3 stable isotopes of Si have been made: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (88.25%). Concentrations of electrically active impurities (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.

  1. Cyanex 923 as the extractant in a rare earth element impurity analysis of high-purity cerium oxide.

    Science.gov (United States)

    Duan, Taicheng; Li, Hongfei; Kang, JianZhen; Chen, Hangting

    2004-06-01

    In this work, the feasibility of employing Cyanex 923 as an extractant into the non-cerium REE (rare earth elements) impurity analysis of high-purity cerium oxide was investigated. Through investigations on the choice of the extraction medium, the optimium extraction acidity, matrix Ce4+ effect on the non-cerium REE ion extraction, the optimium extractant concentration and suitable extracting time, and oscillation strengh, it was found that when the phase ratio was at 1:1 and the acicidity was about 2% H2SO4, by gently shaking by hand for about 2 min, 10 mL of 30% Cyanex 923 could not extract even for a 20 ng amount of non-cerium REE3+ ions. However, the extraction efficiency for Ce4+ of 100 mg total amount under the same conditions was about 96%, indicating that a 25-fold preconcentration factor could be achieved. Thus, it was concluded that Cyanex 923 could be used in a REE impurity analysis of 99.9999% or so pure cerium oxide for primary sepapation to elimilate matrix-induced interferences encountered in an ICP-MS (inductively coupled plasma mass spectroscopy) determination.

  2. Study of corrosion processes on Al-AA 6061 crevices immersed in high purity water and sodium citrate solution

    International Nuclear Information System (INIS)

    An experimental approach has been developed to study the corrosion behavior of artificial crevices manufactured with high purity aluminum and AA 6061 alloy, immersed in dematerialised water and sodium citrate solution (96,5 μS/cm). Alkaline attack was found on the surrounding of iron rich particles in the external zone of the crevice, as a result of localized oxygen reduction reaction on these sites. This attack was not observed in the zone inside the crevice. Study of the phase Mg2Si by EDS allowed establishing that there is not preferential dissolution inside the crevice. The formation of a stable and non-soluble complex between Al and citrate anion inhibited the production of Al(OH)3 precipitate, which was observed on the surface of specimens immersed in pure water. Investigations of the aluminum oxide evolution on AA 6061 surfaces in water showed that it was composed by two layers: an internal one made of Bohemite and an external one in direct contact with the water, with a Bayerite structure. The surface analysis was accomplished using XR, OM and SEM techniques. (author)

  3. Trace analysis of U, Th and other heavy metals in high purity aluminium with isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    A method for the determination of very low concentrations of U, Th, Fe, Zn, Tl, Cd, Cu and Ag in high purity aluminium with isotope dilution mass spectrometry (IDMS) is developed using a compact and cost-efficient thermal ionization quadrupole mass spectrometer. The detection limits obtained are (in ng/g):U=0.018, Th=0.06, Fe=82, Zn=86, Tl=0.2, Cd=4, Cu=1, Ag=2.6. By this method it is possible to determine the α-emitters U and Th in aluminium down to the sub-ng/g level with good precision of 0.4-10% and 0.5-5%, respectively. The results should also be accurate because IDMS is a reliable analytical method. The dissolution of aluminium is carried out by aqua regia followed by the trace/matrix separation and the isolation of the trace elements by anion exchange chromatography (U, Th, Zn, Tl, Cd), electrodeposition (Cu, Ag) and extraction (Fe). Different aluminium samples are analysed by IDMS and the results are compared with those of other methods. (orig.)

  4. High-purity isolation of anthocyanins mixtures from fruits and vegetables--a novel solid-phase extraction method using mixed mode cation-exchange chromatography.

    Science.gov (United States)

    He, Jian; Giusti, M Monica

    2011-11-01

    Research on biological activity of anthocyanins requires the availability of high purity materials. However, current methods to isolate anthocyanins or anthocyanin mixtures are tedious and expensive or insufficient for complete isolation. We applied a novel cation-exchange/reversed-phase combination solid-phase extraction (SPE) technique, and optimized the use of water/organic buffer mobile phases to selectively separate anthocyanins. Crude extracts of various representative anthocyanin sources were purified with this technique and compared to 3 commonly used SPE techniques: C(18), HLB, and LH-20. Purified anthocyanin fractions were analyzed with high performance liquid chromatography (HPLC) coupled to photodiode array (PDA) and mass spectrometry (MS) detectors and by Fourier transform infrared (FT-IR) spectroscopy. The UV-visible chromatograms quantitatively demonstrated that our novel technique achieved significantly higher (Pmethod, for 11 of the 12 anthocyanin sources tested. Among them, eight were purified to greater than 99% purity (based on UV-visible chromatograms). The new method efficiently removed non-anthocyanin phenolics. MS and FT-IR results semi-quantitatively confirmed extensive reduction of impurities. Due to strong ionic interaction, our sorbent capacity was superior to others, resulting in the highest throughput and least use of organic solvents. This new methodology for isolation of anthocyanin mixtures drastically increased purity and efficiency while maintaining excellent recovery rate and low cost. The availability of high purity anthocyanin mixtures will facilitate anthocyanin studies and promote the application of anthocyanins in the food and nutraceutical industries. PMID:21968344

  5. The Production of High Purity Phycocyanin by Spirulina platensis Using Light-Emitting Diodes Based Two-Stage Cultivation.

    Science.gov (United States)

    Lee, Sang-Hyo; Lee, Ju Eun; Kim, Yoori; Lee, Seung-Yop

    2016-01-01

    Phycocyanin is a photosynthetic pigment found in photosynthetic cyanobacteria, cryptophytes, and red algae. In general, production of phycocyanin depends mainly on the light conditions during the cultivation period, and purification of phycocyanin requires expensive and complex procedures. In this study, we propose a new two-stage cultivation method to maximize the quantitative content and purity of phycocyanin obtained from Spirulina platensis using red and blue light-emitting diodes (LEDs) under different light intensities. In the first stage, Spirulina was cultured under a combination of red and blue LEDs to obtain the fast growth rate until reaching an absorbance of 1.4-1.6 at 680 nm. Next, blue LEDs were used to enhance the concentration and purity of the phycocyanin in Spirulina. Two weeks of the two-stage cultivation of Spirulina yielded 1.28 mg mL(-1) phycocyanin with the purity of 2.7 (OD620/OD280). PMID:26433600

  6. S2- behaviors analysis in leaching SrS and precipitating high purity SrCO3 by reduction-decomposition process

    Institute of Scientific and Technical Information of China (English)

    彭晓东; 刘相果; 谢卫东; 刘江; 贾上远; 权燕燕

    2004-01-01

    A new preparation method (reduction-decomposition process) for high purity SrCO3 was investigated,which mainly includes four processes: reduction, leaching, purification and precipitation. The affecting factors about S2- behaviors in leaching process and the effects of variables on purity and particle sizes distribution of SrCO3 were analyzed theoretically and practically. It is concluded that with the increase of temperature or decrease of pH value in leaching process, the strontium recovery increases, but SrS decomposes and hydrogen sulphide (H2S) gasdischarges. The purity of SrCO3 is dependent on dissolution-recrystallization times, for example, the purity of SrCO3 is as high as 99.97% when it is recrystallized three times. Besides, the solution concentration of Sr(OH)2and flow rate of CO2 have important effects on particle size distribution of SrCO3 particles, especially, the particle sizes of SrCO3 meanly distribute in 0.1 - 1.0μm when the flow rate of CO2 is about 2 000 mL/min and other parameters are invariable.

  7. Preparation of High Purity Crystalline Silicon by Electro-Catalytic Reduction of Sodium Hexafluorosilicate with Sodium below 180°C

    OpenAIRE

    Chen, Yuan; Liu, Yang; Wang, Xin; Li, Kai; Chen, Pu

    2014-01-01

    The growing field of silicon solar cells requires a substantial reduction in the cost of semiconductor grade silicon, which has been mainly produced by the rod-based Siemens method. Because silicon can react with almost all of the elements and form a number of alloys at high temperatures, it is highly desired to obtain high purity crystalline silicon at relatively low temperatures through low cost process. Here we report a fast, complete and inexpensive reduction method for converting sodium ...

  8. Unique Low-molecular-weight Lignin with High Purity Extracted from Wood by Deep Eutectic Solvents (DES): A Source of Lignin for Valorization

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Vasco, Carlos A.; Ma, Ruoshui; Quintero, Melissa; Guo, Mond; Geleynse, Scott C.; Kallupalayam Ramasamy, Karthikeyan; Wolcott, Michael P.; Zhang, Xiao

    2016-06-08

    This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from Choline Chloride (ChCl) and four hydrogen-bond donors–acetic acid, lactic acid, levulinic acid and glycerol–were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkages in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.

  9. The Globe laid bare

    CERN Multimedia

    Fortunati, Lucien

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.

  10. Determination of trace selenium in high purity tellurium by hydride generation atomic fluorescence spectrometry after solid phase extraction of a diaminobenzidine-selenium chelate

    Science.gov (United States)

    Tong, Wang; Ying, Zeng; Jinyong, Xu

    2016-09-01

    Macroporous adsorption resin was used as the sorbent for solid phase extraction and determination of the trace Se content in high purity tellurium prior to hydride generation atomic fluorescence spectrometry analysis. Selenium was converted into an organic Se chelate using 3,3‧-diaminobenzidine and was separated from the tellurium matrix by solid phase extraction. The resin was packed as a column for solid phase extraction. Under optimum conditions, trace Se can be quantitatively extracted and the tellurium matrix can be removed. The Se in the eluate was determined by hydride generation atomic fluorescence spectrometry. The limit of detection (3σ) of this method was 0.22 ng g- 1 and the relative standard deviation (RSD, n = 5) ranged from 2.0 to 2.5% for the three investigated tellurium samples. The proposed method was successfully applied for the determination of the trace Se content in high purity tellurium samples.

  11. Effects of 600 MeV proton irradiation on nucleation and growth of precipitates and helium bubbles in a high-purity Al-Mg-Si alloy

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Victoria, M.;

    1986-01-01

    Solution treated specimens of a high-purity Al-0.75%Mg-0.42%Si alloy were irradiated with 600 MeV protons at 150 and 240°C to a dose level of 0.47 and 0.55 dpa, respectively. Mg2Si-type precipitates formed during irradiation at 150 and 240°C; at 240°C, however, a large number of precipitates seem...

  12. Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

    Energy Technology Data Exchange (ETDEWEB)

    Alexander S. Chernyshov

    2006-08-09

    Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac magnetic susceptibility, and heat capacity of high purity single crystals of dysprosium have been investigated over broad temperature and magnetic field intervals with the magnetic field vector parallel to either the a- or c-axes of the crystal. Notable differences in the behavior of the physical properties when compared to Dy samples studied in the past have been observed between 110 K and 125 K, and between 178 K and {approx}210 K. A plausible mechanism based on the formation of antiferromagnetic clusters in the impure Dy has been suggested in order to explain the reduction of the magnetocaloric effect in the vicinity of the Neel point. Experimental and theoretical investigations of the influence of commensurability effects on the magnetic phase diagram and the value of the magnetocaloric effect have been conducted. The presence of newly found anomalies in the physical properties has been considered as evidence of previously unreported states of Dy. The refined magnetic phase diagram of dysprosium with the magnetic field vector parallel to the a-axis of a crystal has been constructed and discussed. The magnetic and crystallographic properties of Gd{sub 5}Sb{sub x}Ge{sub 4-x} pseudo-binary system were studied by x-ray diffraction (at room temperature), heat capacity, ac-magnetic susceptibility, and magnetization in the temperature interval 5-320 K in magnetic fields up to 100 kOe. The magnetic properties of three composition (x = 0.5, 1,2) were examined in detail. The Gd{sub 5

  13. Intergranular corrosion of 13Cr and 17Cr martensitic stainless steels in accelerated corrosive solution and high-temperature, high-purity water

    International Nuclear Information System (INIS)

    Intergranular corrosion behavior of 13Cr and 17Cr martensitic stainless steels was studied by electrochemical and immersing corrosion tests. Effects of the mEtallurgical and environmental conditions on the intergranular corrosion of various tempered steels were examined by the following tests and discussed. (a) Anodic polarization measurement and electrolytical etching test in 0.5 kmol/m3 H2SO4 solution at 293 K. (b) Immersion corrosion test in 0.88 kmol/m3 HNO3 solution at 293 K. (c) Long-time immersion test for specimens with a crevice in a high purity water at 473 K∼561 K. It was found from the anodic polarization curves in 0.5 kmol/m3 H2SO4 solution-at 293 K that the steels tempered at 773∼873 K had susceptibility to intergranular corrosion in the potential region indicating a second current maximum (around-0.1 V. vs. SCE). But the steel became passive in the more noble potential region than the second current peak potential, while in the less noble potential region general corrosion occurred independent of its microstructure. The intergranular corrosion occurred due to the localized dissolution along the pre-austenitic grain boundary and the martensitic lath boundary. It could be explained by the same dissolution model of the chromium depleted zone as proposed for the intergranular corrosion of austenitic and ferritic stainless steels. The intergranular corrosion occurred entirely at the free surface in 0.88 kmol/m3 HNO3 solution, while in the high temperature and high purity water only the entrance of the crevice corroded. It was also suggested that this intergranular corrosion might serve as the initiation site for stress corrosion cracking of the martensitic stainless steel. (author)

  14. Intergranular corrosion of 13Cr and 17Cr martensitic stainless steels in accelerated corrosive solution and high-temperature, high-purity water

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Toshinori; Ishikawa, Yuichi

    1988-12-01

    Intergranular corrosion behavior of 13Cr and 17Cr martensitic stainless steels was studied by electrochemical and immersing corrosion tests. Effects of the metallurgical and environmental conditions on the intergranular corrosion of various tempered steels were examined by the following tests and discussed. (a) Anodic polarization measurement and electrolytical etching test in 0.5 kmol/m/sup 3/ H/sub 2/SO/sub 4/ solution at 293 K. (b) Immersion corrosion test in 0.88 kmol/m/sup 3/ HNO/sub 3/ solution at 293 K. (c) Long-time immersion test for specimens with a crevice in a high purity water at 473 K/similar to/561 K. It was found from the anodic polarization curves in 0.5 kmol/m/sup 3/ H/sub 2/SO/sub 4/ solution-at 293 K that the steels tempered at 773/similar to/873 K had susceptibility to intergranular corrosion in the potential region indicating a second current maximum (around-0.1 V. vs. SCE). But the steel became passive in the more noble potential region than the second current peak potential, while in the less noble potential region general corrosion occurred independent of its microstructure. The intergranular corrosion occurred due to the localized dissolution along the pre-austenitic grain boundary and the martensitic lath boundary. It could be explained by the same dissolution model of the chromium depleted zone as proposed for the intergranular corrosion of austenitic and ferritic stainless steels. The intergranular corrosion occurred entirely at the free surface in 0.88 kmol/m/sup 3/ HNO/sub 3/ solution, while in the high temperature and high purity water only the entrance of the crevice corroded. It was also suggested that this intergranular corrosion might serve as the initiation site for stress corrosion cracking of the martensitic stainless steel.

  15. Determination of nickel, cobalt, copper, thorium and uranium in high-purity zinc metal by ICP-MS with on-line matrix separation

    International Nuclear Information System (INIS)

    Traces of Co, Cu, Ni, Th and U in high-purity zinc metal were determined by inductively coupled plasma mass spectrometry (ICP-MS) in combination with flow-injection (FI) on-line matrix separation (FI-ICP-MS). The anion-exchange separation method of an HCl system was applied to the separation of Ni, Co, Cu, Th and U from zinc matrix. The matrix element, zinc, was adsorbed on an anion-exchange (BIO·RAD AG1-X8) mini-column (2.0 mm i.d. x 300 mm bed length), while the analytes were directly introduced into the ICP-MS. The following detection limits (in ng g-1) were obtained: Ni, 3.1; Co, 1.2; Cu, 4.0; Th, 0.12 and U, 0.48. The reproducibility has proved to be satisfactory with a relative standard deviation of less than 5% (at the 10 ng ml-1 level, n=3). The method was successfully applied to determining trace impurities in three 6 and 7 nines grade of high-purity zinc metals and in three standard reference materials of high-purity zinc metal samples (from NIST). (author)

  16. Very Late Bare Metal Stent Thrombosis

    Directory of Open Access Journals (Sweden)

    Mariana Soto Herrera

    2013-01-01

    Full Text Available Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation.

  17. Very Late Bare Metal Stent Thrombosis

    Science.gov (United States)

    Soto Herrera, Mariana; Restrepo, José A.; Felipe Buitrago, Andrés; Gómez Mejía, Mabel; Díaz, Jesús H.

    2013-01-01

    Very late stent thrombosis is a rare and not-well-understood complication after bare metal stent implantation. It usually presents as an ST elevation acute coronary syndrome and it is associated with high rates of morbidity and mortality. Pathophysiologic mechanisms are not well defined; nevertheless, recent studies have proposed a neoatherosclerotic process as the triggering mechanism. We present the case of a patient with bare metal very late stent thrombosis 12 years after implantation. PMID:24829831

  18. Comparison of a high-purity HOSP trademark PYSZ powder with standard HOSP: powder/coating characterization and thermal cycling testing

    Energy Technology Data Exchange (ETDEWEB)

    Gray, S.; Lawson, K.J. [Cranfield Univ., Bedford (United Kingdom); Dorfman, M.R. [Sulzer Metco (America) Inc., Westbury, NJ (United States)

    2008-07-01

    A high-purity (HP) HOSP trademark (Hollow Oven Spherical Process) PYSZ powder has been evaluated and compared to standard PYSZ powders. The main difference is these two powders is the starting raw material purity. Four TBC systems (2 standard types and 2 high purity versions) were Air Plasma Sprayed (APS) onto CMSX-4 substrates with APS CoNiCrAlY bond coats. Thermal shock testing was performed to 50% spallation at 1135 C with 1 hour hot cycles with forced air cooling. The as-deposited coatings and those after thermal shock failure were characterized using X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The thermal cycling results show little difference in the thermal shock resistance of the coatings with all failing in an adhesive manner with failures occurring in excess of 180 hot cycles. XRD and Raman data is used to identify the levels of monoclinic and tetragonal phases present in each coating and SEM analysis used to identify differences between PYSZ with a broad particle size distribution and a tighter controlled PYSZ particle size distribution. (orig.)

  19. Optimal recovery of high-purity rutin crystals from the whole plant of Fagopyrum esculentum Moench (buckwheat) by extraction, fractionation, and recrystallization.

    Science.gov (United States)

    Kim, Kyoung Heon; Lee, Ki Won; Kim, Dong Young; Park, Hyung Hwan; Kwon, Ik Boo; Lee, Hyong Joo

    2005-10-01

    Rutin, one of the flavonoids derived from plants, is increasingly in demand in the food, pharmaceutical, and cosmetic industries due to its various biological and physiological activities including antioxidation, anti-inflammation, and anti-hypertension. The whole plant of buckwheat (Fagopyrum esculentum Moench) is a major source of natural rutin. This study developed a low-cost process encompassing the efficient extraction, fractionation, and recrystallization to obtain high-purity rutin from buckwheat, and it could improve the economic utilization of this abundant low-value agricultural product. The sequential separation and purification procedures established in this study involved extraction with 50% (v/v) aqueous ethanol at 80 degrees C for 1 h followed by elution with water and aqueous ethanols at 20% and 30% (v/v) on a styrene-based resin column, and recrystallization at 4 degrees C for 12 h. These conditions resulted in the recovery of 92% of total rutin with over 95% purity. In the present study, high-purity rutin was obtained from whole buckwheat through low-cost processes, the separation and purification strategy established in this study could provide valuable information to the relevant industries.

  20. Synthesis of high purity gallium nitride powders and growth and characterization of aluminum nitride and gallium nitride bulk single crystals

    Science.gov (United States)

    Balkas, Cengiz Mustafa

    Single crystalline platelets of aluminum nitride (AlN) ≤ 1 mm thick have been grown within the range 1950-2250sp°C on silicon carbide (SiC) substrates via sublimation-recondensation in a resistively heated graphite furnace. The source material was sintered AlN. A maximum growth rate of 500 mum/hr was achieved at 2150sp°C and a source-to-seed separation of 4 mm. Crystals grown at high temperatures ranged in color from blue to green due to the incorporation of Si and C from the SiC substrates; those grown at lower temperatures were colorless and transparent. Secondary-ion mass spectroscopy (SIMS) results showed approximately a two order of magnitude decrease in the concentrations of these two impurities in the transparent crystals. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy studies revealed low densities of line and planar defects and a strain free material. The synthesis of high purity, single phase GaN powders was accomplished in a hot wall tube furnace via (1) the reaction of Ga(l) with ammonia (NHsb3) and (2) the conversion of Gasb2Osb3(s). Polyhedra of various shapes were obtained from both processes; some rod-shaped crystals were also observed in the material derived from Gasb2Osb3. The GaN powders produced via the first route were characterized via XRD technique. The diffraction data revealed the material to be single phase with a = 3.1891 A, c = 5.1855 A, in space group P6sb3mc, Z = 2 and Dsb{x} = 6.0886 gr/cmsp3. Scanning electron microscopy revealed a particle size distribution in the ground material between 1 and 5 mum with most of the particles being {≈}1{mu}m. The data obtained in this study was chosen to be the new standard for the powder diffraction pattern for this material by the International Center for Diffraction Data. Single crystals of GaN up to 3 mm in length were grown by sublimation of pellets of this material under an NHsb3 flow. Typical green densities were 50 to 60% of theoretical density

  1. 双环戊二烯解聚法制备高纯环戊二烯%Preparation of High Purity Cyclopentadiene by the Depolymerization of Dicyclopentadiene

    Institute of Scientific and Technical Information of China (English)

    芦齐; 李琪; 乔庆东

    2011-01-01

    The high purity cyclopentadiene(CPD) was prepared by using industrial raw dicyclopentadiene(DCPD).The raw materials and cyclopentadiene obtained by the depolymerization of dicyclopentadiene were analyzed by gas chromatography with SE-30 quartz capillary column.The raw material was purified, then was carried out thermal dimerization at 120 ℃ and depolymerization at 175~180 ℃.The purity of cyclopentadiene obtained by this way is more than 99%.Cyclopentadiene is very easy to polymerize and the purity of it after long time decreases remarkably, so it must be used as soon as.%采用工业粗品双环戊二烯(DCPD)为原料制备高纯度的环戊二烯(CPD),通过SE-30石英毛细管柱对原料和解聚后得到的环戊二烯进行气相色谱分析.对原料进行提纯,以120℃进行热二聚,最后在175~180℃进行解聚,得到的新鲜环戊二烯的纯度可达到99%以上.解聚后得到的环戊二烯在室温下极易发生聚合反应,长时间放置纯度大幅度降低,应立即使用.

  2. Survivability of bare, individual Bacillus subtilis spores to high-velocity surface impact: Implications for microbial transfer through space

    Science.gov (United States)

    Barney, Brandon L.; Pratt, Sara N.; Austin, Daniel E.

    2016-06-01

    Laboratory experiments show that endospores of Bacillus subtilis survive impact against a solid surface at velocities as high as 299 ±28 m/s. During impact, spores experience and survive accelerations of at least 1010 m/s2. The spores were introduced into a vacuum chamber using an electrospray source and accelerated to a narrow velocity distribution by entrainment in a differentially pumped gas flow. Different velocity ranges were studied by modifying the gas flow parameters. The spores were electrically charged, allowing direct measurement of the velocity of each spore as it passed through an image charge detector prior to surface impact. Spores impacted a glass surface and were collected for subsequent analysis by culturing. Most spores survived impact at all measured velocities. These experiments differ fundamentally from other studies that show either shock or impact survivability of bacteria embedded within or on the surface of a projectile. Bacteria in the present experiments undergo a single interaction with a solid surface at the full impact velocity, in the absence of any other effects such as cushioning due to microbe agglomerations, deceleration due to air or vapor, or transfer of impact shock through solid or liquid media. During these full-velocity impact events, the spores experience extremely high decelerations. This study is the first reported instance of accelerations of this magnitude experienced during a bacteria impact event. These results are discussed in the context of potential transfer of viable microbes in space and other scenarios involving surface impacts at high velocities.

  3. Measurement of the high-field Q-drop in a high-purity large-grain niobium cavity for different oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Kneisel, Peter; gurevich, alex

    2007-06-01

    The most challenging issue for understanding the performance of superconducting radio-frequency (rf) cavities made of high-purity (residual resistivity ratio > 200) niobium is due to a sharp degradation (“Q-drop”) of the cavity quality factor Q0(Bp) as the peak surface magnetic field (Bp) exceeds about 90 mT, in the absence of field emission. In addition, a low-temperature (100 – 140 C) “in-situ” baking of the cavity was found to be beneficial in reducing the Q-drop. In this contribution, we present the results from a series of rf tests at 1.7 K and 2.0 K on a single-cell cavity made of high-purity large (with area of the order of few cm2) grain niobium which underwent various oxidation processes, after initial buffered chemical polishing, such as anodization, baking in pure oxygen atmosphere and baking in air up to 180 °C, with the objective of clearly identifying the role of oxygen and the oxide layer on the Q-drop. During each rf test a temperature mapping system allows measuring the local temperature rise of the cavity outer surface due to rf losses, which gives information about the losses location, their field dependence and space distribution. The results confirmed that the depth affected by baking is about 20 – 30 nm from the surface and showed that the Q-drop did not re-appear in a previously baked cavity by further baking at 120 °C in pure oxygen atmosphere or in air up to 180 °C. These treatments increased the oxide thickness and oxygen concentration, measured on niobium samples which were processed with the cavity and were analyzed with Transmission Electron Microscope (TEM) and Secondary Ion Mass Spectroscopy (SIMS). Nevertheless, the performance of the cavity after air baking at 180 °C degraded significantly and the temperature maps showed high losses, uniformly distributed on the surface, which could be completely recovered only by a post-purification treatment at 1250 °C. A statistic of the position of the “hot-spots” on the

  4. On The Generation of Interferometric Colors in High Purity and Technical Grade Aluminum: An Alternative Green Process for Metal Finishing Industry

    International Nuclear Information System (INIS)

    Graphical abstract: Toward green processes in metal finishing industry by rationally designed electrochemical anodization. Biomimetic photonic films based on nanoporous anodic alumina produced in high purity and technical grade aluminum foils display vivid colors that can be precisely tuned across the visible spectrum. The presented method is a solid rationale aimed toward green processes for metal finishing industry. - Highlights: • Environmentally friendly approach to color aluminum through biomimetic photonic films. • Nanoporous anodic alumina distributed Bragg Reflectors (NAA-DBRs). • Rationally designed galvanostatic pulse anodization approach. • Macroscopic and microscopic differences in high purity and technical grade aluminum. • Substitute method for conventional coloring processes in metal finishing industry. - Abstract: Metal finishing industry is one of the leading pollutants worldwide and green approaches are urgently needed in order to address health and environmental issues associated with this industrial activity. Herein, we present an environmentally friendly approach aimed to overcome some of these issues by coloring aluminum through biomimetic photonic films based on nanoporous anodic alumina distributed Bragg Reflectors (NAA-DBRs). Our study aims to compare the macroscopic and microscopic differences between the resulting photonic films produced in high purity and technical grade aluminum in terms of color features, appearance, electrochemical behavior and internal nanoporous structure in order to establish a solid rationale toward optimal fabrication processes that can be readily incorporated into industrial methodologies. The obtained results reveal that our approach, based on a rational galvanostatic pulse anodization approach, makes it possible to precisely generate a complete palette of colors in both types of aluminum substrates. As a result of its versatility, this method could become a promising alternative to substitute

  5. Preparation of Monodisperse and High-purity Silica Packing Materials%单分散高纯硅胶色谱柱填料的制备

    Institute of Scientific and Technical Information of China (English)

    杨俊佼; 张硕

    2012-01-01

    在氨水和氨气催化下使单晶硅粉水解,合成了单分散、高纯的纳米二氧化硅水溶胶;再利用聚合诱导胶体凝聚法(PICA)制备单分散脲醛二氧化硅复合微球,经过高温煅烧后得到球形硅胶色谱柱填料.通过电感耦合等离子-质谱(ICP-MS)、电子显微镜和BET比表面积测试等手段对球形硅胶的纯度、粒径分布及比表面积进行了表征,并通过色谱分离对硅胶填料的性能进行了评价.实验结果表明,该方法合成的色谱柱填料具有纯度高、粒径分布均匀、机械强度高及分离能力强等优点.%Using silicon powder as silica source, monodisperse and high-purity nano-silica sol was synthesized under catalysis of aqueous ammonia and ammonia gas. The urea-form aldehyde polymer/SiO, composite micro-spheres were prepared after polymerization-induced colloid aggregation ( PICA) method in acidic media, and the spherical silica packing material was produced after calcining at high temperature. The purity of monodisperse nano-silica sol was tested by inductively coupled plasma mass spectrometry (ICP-MS) , and the size and shape of the composite microspheres were characterized by scanning electron microscope ( SEM) . The performance of silica packing material was evaluated by non-chromatographic method ( BET) and chromatographic method. The results show that the silica packing material has high purity, uniformity and high mechanical strength.

  6. Influence of power density on high purity 63 mm diameter polycrystalline diamond deposition inside a 2.45 GHz MPCVD reactor

    Science.gov (United States)

    Yu, Shengwang; Wang, Rong; Zheng, Ke; Gao, Jie; Li, Xiaojing; Hei, Hongjun; Liu, Xiaoping; He, Zhiyong; Shen, Yanyan; Tang, Bin

    2016-09-01

    63 mm diameter polycrystalline diamond (PCD) films were synthesized via a microwave plasma chemical vapor deposition (MPCVD) reactor in 99% H2-1% CH4 atmosphere. Two different conditions, i.e. the typical condition (input power of 5 kW and gas pressure of 13 kPa) and the high power density condition (input power of 10 kW and gas pressure of 18 kPa), were employed for diamond depositions. The color changes of the plasma under the two proposed conditions with and without methane were observed by photographs. Likewise, the concentrations of hydrogen atoms and carbon active chemical species in plasma were analyzed by optical emission spectroscopy (OES). The morphologies and purity of the PCD films were investigated by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. Finally, the transmission spectrum of the polished PCD plates was characterized by a UV-Vis-NIR spectrometer. Experimental results showed that both the concentrations of hydrogen atoms and carbon radicals increased obviously, with the boost input power and higher pressure. The films synthesized under the high power density condition displayed higher purity and more uniform thickness. The growth rates in 10 kW and 18 kPa reached ~7.7 µm h-1, approximately 6.5 times as much as that occurred in the typical process. Moreover, the polished plates synthesized under the high power density condition possessed a relatively high optical transmittance (~69%), approaching the theoretical values of approximately 71.4% in IR. These results indicate that the purity and growth rate of big-area PCD films could be simultaneously increased with power density.

  7. Preparation of High Purity, High Molecular-Weight Chitin from Ionic Liquids for Use as an Adsorbate for the Extraction of Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Robin [Univ. of Alabama, Tuscaloosa, AL (United States)

    2013-12-21

    Ensuring a domestic supply of uranium is a key issue facing the wider implementation of nuclear power. Uranium is mostly mined in Kazakhstan, Australia, and Canada, and there are few high-grade uranium reserves left worldwide. Therefore, one of the most appealing potential sources of uranium is the vast quantity dissolved in the oceans (estimated to be 4.4 billion tons worldwide). There have been research efforts centered on finding a means to extract uranium from seawater for decades, but so far none have resulted in an economically viable product, due in part to the fact that the materials that have been successfully demonstrated to date are too costly (in terms of money and energy) to produce on the necessary scale. Ionic Liquids (salts which melt below 100{degrees}C) can completely dissolve raw crustacean shells, leading to recovery of a high purity, high molecular weight chitin powder and to fibers and films which can be spun directly from the extract solution suggesting that continuous processing might be feasible. The work proposed here will utilize the unprecedented control this makes possible over the chitin fiber a) to prepare electrospun nanofibers of very high surface area and in specific architectures, b) to modify the fiber surfaces chemically with selective extractant capacity, and c) to demonstrate their utility in the direct extraction and recovery of uranium from seawater. This approach will 1) provide direct extraction of chitin from shellfish waste thus saving energy over the current industrial process for obtaining chitin; 2) allow continuous processing of nanofibers for very high surface area fibers in an economical operation; 3) provide a unique high molecular weight chitin not available from the current industrial process, leading to stronger, more durable fibers; and 4) allow easy chemical modification of the large surface areas of the fibers for appending uranyl selective functionality providing selectivity and ease of stripping. The

  8. Effect of Carbon on Grain Boundary Segregation of Phosphorus and Phosphorus-Induced Intergranular Fracture in High Purity Iron with Phosphorus

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The segregation of carbon at grain boundaries and its effect on phosphorus segregation and phosphorus-induced intergranular fracture in the alloy of high purity iron with phosphorus were investigated by scanning Auger electron spectroscopy, impact test and SEM observation of fractured surface. The experimental results showed that the carbon segregation at grain boundaries decreases the phosphorus segregation, and a change of fracture mode from intergranular fracture to transgranular one, hence a decrease of ductile-brittle transition temperature is observed. The mechanism of these effects was discussed.

  9. A study on the influence of trace elements (C, S, B, Al, N) on the hot ductility of the high purity austenitic alloy Fe-Ni 36% (INVAR)

    Energy Technology Data Exchange (ETDEWEB)

    Simonetta-Perrot, M.T.

    1994-11-01

    In order to study the damage mechanisms leading to the ductility decrease of the Invar alloy at 600 C, a high-purity Fe-Ni 36% sample has been doped with trace elements with the purpose of identifying the role of sulfur, sulfur with Al N or B N precipitates and sulfur with boron, on the ductility, the failure modes, the intergranular damage and the plastic deformation mechanisms prior to failure. A new AES segregation quantification method has been used to study the kinetics and thermodynamics of intergranular and surface segregations and determine the relation between sulfur segregation and grain joint fragility. refs., figs., tabs.

  10. Progress in Catalytic Membrane Reactors for High Purity Hydrogen Production%膜催化反应器及其制氢技术的研究进展

    Institute of Scientific and Technical Information of China (English)

    闫云飞; 张力; 李丽仙; 唐强

    2011-01-01

    As a kind of ideal fuel for fuel cell, hydrogen must be satisfied with the enough high purity. To produce high purity hydrogen at a low cost and large scale method has become a key research focus in the industrialization of fuel-cell technology. The membrane catalytic technology with catalysis and separation dual functions has been developed in recent years, which is a good method to produce high purity hydrogen. Based on the latest developments in the membrane catalytic reaction fields, the advantages, composition and type of membrane catalytic reactor are summarized. The preparation techniques, advantages and classification of inorganic membrane materials are described. Especially, the progress and application for high purity hydrogen production are reviewed in three kinds of catalytic membrane reactors, including oxygen-permeable membrane reactor, hydrogen-permeation membrane reactor and double-membranes reactor. The existing problems of catalytic membrane and membrane catalytic reactor in the industrialization process of hydrogen production using the membrane catalytic technology are also discussed. Additionally, the prospects of membrane catalytic reactors for hydrogen production is proposed.%燃料电池对其理想燃料氢气的纯度要求极高,如何低成本、大规模制取高纯氢气己成为燃料电池技术实现工业化的一个关键问题和研究热点.近年发展起来的兼具催化与分离双重功能的膜催化反应技术是实现制取高纯氢气的一个有效途径.本文结合膜催化反应领域的最新进展,综述了膜催化反应器的优点、组成、类型;介绍了无机膜材料的优点、分类及制备技术;详细综述了透氧膜催化反应器、透氢膜催化反应器及双膜催化反应器在制氢过程中的研究进展和应用,指出了膜催化反应制氢技术在工业化发展过程中存在的问题及应用前景.

  11. Determination of ultra-trace amounts of uranium and thorium in high-purity aluminium by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    A sensitive method is described for the simultaneous determination of ultra-trace amounts of uranium and thorium in high-purity aluminium by inductively coupled plasma mass spectrometry (ICP-MS). Uranium and thorium were separated from a sample solution of 10 mol dm-3 hydrochloric acid by extraction with a 10% v/v solution of tributyl phosphate in cyclohexane. The internal standard method was used for quantification by ICP-MS. For a sample mass of 10 g, the detection limits for uranium and thorium are 7 and 8 pg g--1, respectively. (Author)

  12. Study on Refining Process for High Purity Yb2O3%高纯氧化镱制备工艺研究

    Institute of Scientific and Technical Information of China (English)

    杨桂林

    2001-01-01

    通过小型实验和扩大实验研究了用 Cl-P507 萃取色层法制备高纯氧化镱的工艺流程和工艺条件,重点考查了淋洗酸度对分离效果的影响规律。在扩大实验中,色谱柱为Φ102 mm×2000 mm,以99% Yb2O3 为原料,载量 1.06%,在常温下单柱一次分离获得 99.999% 的高纯 Yb2O3,直接收率大于 85.5%。并且详细列出了产品杂质分析结果,对工艺的优缺点及相关的技术经济指标也进行了分析。%A refining process for high purity(>99.999%) Yb2O3 was studied. The process can be fulfilled by a column extraction-chromatography of Cl-P507 resin at room temperature. Multifold elution was applied for separating the impurities and the elution acidity was in the range of 1.0~3.0 mol/L HCl. The scale of column is Φ102 mm×2000 mm and the loading capacity of resin is 1.06%. Taking Yb2O3 with purity 99% as the raw material, the refined product of high purity (99.999%) Yb2O3 was obtained and the recovery of Yb2O3 is more than 85.5%. Besides, the technical-economy profit of the refining process was analyzed.

  13. The Globe laid bare

    CERN Multimedia

    Anaïs Schaeffer

    2015-01-01

    If you’re at CERN at the moment, you will certainly have noticed the work under way on the Globe. The structure, which has been in pride of place opposite the Laboratory for over ten years, has never been so completely laid bare. But, as we explained in a previous article (see here), it is all for a good cause. The Globe is built entirely from wood and certain parts of it need to be replaced.   The Globe after the removal of all the sun baffles. Image: Lucien Fortunati. Picture the general structure of the Globe. In simple terms, the building consists of two spheres, one inside the other. The inner sphere houses the Universe of Particles exhibition and the conference room and is connected to the outer sphere by two access ramps. “Each of these two spheres is made up of eighteen large supporting arcs,” explains Amaya Martínez García of the GS department, who is supervising the Globe renovation project. “These eighteen arcs are ...

  14. High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

    Science.gov (United States)

    Pargoletti, E.; Cappelletti, G.; Minguzzi, A.; Rondinini, S.; Leoni, M.; Marelli, M.; Vertova, A.

    2016-09-01

    Nanostructured MnO2 has unique electrocatalytic properties towards the Oxygen Reduction Reaction (ORR, the main cathodic reaction in metal-air devices), representing an excellent alternative to the expensive platinum. Herein, we report the hydrothermal synthesis of bare and 5% Ti-doped α-MnO2 nanoparticles using two different oxidizing agents, namely ammonium persulfate for MH_N samples and potassium permanganate for MH_K ones. The physico-chemical characterizations show that oxidant cations induce different structural, morphological and surface properties of the final powders. Hence, correlations between the different α-MnO2 characteristics and their electrocatalytic performances towards the ORR are drawn, highlighting the diverse effect even on the kinetic point of view. The ORR activity in alkaline media is examined by means of Staircase - Linear Sweep Voltammetry (S-LSV), using Gas Diffusion Electrode (GDE) as the air-cathode. The presence of these nanoparticles in the GDEs leads to a significant shift of the ORR onset potential (∼100 mV) towards less cathodic values, underlining the electrocatalytic efficiency of all the nanopowders. Furthermore, high exchange current densities (j0) are determined for GDEs with Ti-doped MnO2, comparable to the well-performing Pd45Pt5Sn50, and making it a promising material for the ORR.

  15. Aligned synthesis of multi-walled carbon nanotubes with high purity by aerosol assisted chemical vapor deposition: Effect of water vapor

    International Nuclear Information System (INIS)

    Aligned multi-walled carbon nanotubes (MWCNTs) with high purity and bulk yield were achieved on a silicon substrate by an aerosol-assisted chemical vapor deposition. The introduction of specific amounts of water vapor played a key role in in situ controlling the purity and surface defects of the nanotubes. The morphology, surface quality and structure of MWCNTs were characterized by secondary and backscattered electron imaging in a field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Crystallinity and defects of the MWCNTs' were investigated by high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. In this work, water vapor was found to provide a weak oxidative environment, which enhanced and purified the MWCNTs' growth. However, excessive water vapor would inhibit the MWCNTs growth with a poor surface quality. In addition, it has been found that the surface morphology of the CNTs can be modified intentionally through producing some surface defects by tuning the amount of the water vapor, which may offer more nucleation sites on the chemically inert CNT surface for various applications such as catalyst support.

  16. Preparation of High-purity Ferrous Oxalate%高纯草酸亚铁的制备工艺研究

    Institute of Scientific and Technical Information of China (English)

    蔡敏

    2014-01-01

    The high-purity ferrous oxalate was prepared from ferrous sulphate and oxalic acid using dispersion agent and high-speed dispersion. The affect factors were investigated, and the optical conditions were obtained as followed:dispersion agent concentration 20%(m/m),reaction temperature 30℃,ferrous sulphate concentration 210 g/L,feeding time 40 min.Under the optimum conditions,the yield and purity of the product was 95%and 99.8%, respectively.%以硫酸亚铁、草酸为原料及硫酸溶液为分散剂,通过高速分散均质机,合成了高纯草酸亚铁产品。研究了硫酸亚铁浓度、分散剂浓度、反应时间、反应温度等对产率及纯度的影响,结果表明,当分散剂浓度为20%、硫酸亚铁浓度为210g·L-1、反应温度为30℃、反应时间为40min时,草酸亚铁产率为95%,纯度为99.8%。

  17. High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Naoya, E-mail: naoya.iwamoto@smn.uio.no; Azarov, Alexander; Svensson, Bengt G. [Department of Physics, Center for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Ohshima, Takeshi [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292 Gunma (Japan); Moe, Anne Marie M. [Washington Mills AS, N-7300 Orkanger (Norway)

    2015-07-28

    Effects of high-temperature annealing on deep-level defects in a high-purity semi-insulating 4H silicon carbide substrate have been studied by employing current-voltage, capacitance-voltage, junction spectroscopy, and chemical impurity analysis measurements. Secondary ion mass spectrometry data reveal that the substrate contains boron with concentration in the mid 10{sup 15 }cm{sup −3} range, while other impurities including nitrogen, aluminum, titanium, vanadium and chromium are below their detection limits (typically ∼10{sup 14 }cm{sup −3}). Schottky barrier diodes fabricated on substrates annealed at 1400–1700 °C exhibit metal/p-type semiconductor behavior with a current rectification of up to 8 orders of magnitude at bias voltages of ±3 V. With increasing annealing temperature, the series resistance of the Schottky barrier diodes decreases, and the net acceptor concentration in the substrates increases approaching the chemical boron content. Admittance spectroscopy results unveil the presence of shallow boron acceptors and deep-level defects with levels in lower half of the bandgap. After the 1400 °C annealing, the boron acceptor still remains strongly compensated at room temperature by deep donor-like levels located close to mid-gap. However, the latter decrease in concentration with increasing annealing temperature and after 1700 °C, the boron acceptor is essentially uncompensated. Hence, the deep donors are decisive for the semi-insulating properties of the substrates, and their thermal evolution limits the thermal budget for device processing. The origin of the deep donors is not well-established, but substantial evidence supporting an assignment to carbon vacancies is presented.

  18. High temperature annealing effects on deep-level defects in a high purity semi-insulating 4H-SiC substrate

    Science.gov (United States)

    Iwamoto, Naoya; Azarov, Alexander; Ohshima, Takeshi; Moe, Anne Marie M.; Svensson, Bengt G.

    2015-07-01

    Effects of high-temperature annealing on deep-level defects in a high-purity semi-insulating 4H silicon carbide substrate have been studied by employing current-voltage, capacitance-voltage, junction spectroscopy, and chemical impurity analysis measurements. Secondary ion mass spectrometry data reveal that the substrate contains boron with concentration in the mid 1015 cm-3 range, while other impurities including nitrogen, aluminum, titanium, vanadium and chromium are below their detection limits (typically ˜1014 cm-3). Schottky barrier diodes fabricated on substrates annealed at 1400-1700 °C exhibit metal/p-type semiconductor behavior with a current rectification of up to 8 orders of magnitude at bias voltages of ±3 V. With increasing annealing temperature, the series resistance of the Schottky barrier diodes decreases, and the net acceptor concentration in the substrates increases approaching the chemical boron content. Admittance spectroscopy results unveil the presence of shallow boron acceptors and deep-level defects with levels in lower half of the bandgap. After the 1400 °C annealing, the boron acceptor still remains strongly compensated at room temperature by deep donor-like levels located close to mid-gap. However, the latter decrease in concentration with increasing annealing temperature and after 1700 °C, the boron acceptor is essentially uncompensated. Hence, the deep donors are decisive for the semi-insulating properties of the substrates, and their thermal evolution limits the thermal budget for device processing. The origin of the deep donors is not well-established, but substantial evidence supporting an assignment to carbon vacancies is presented.

  19. 高纯氢氧化镁非均相合成与表征%Synthesis and Characterization of High-purity Magnesium Hydroxide by Heterogenous Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    王景峰; 周莹莹; 胡宏; 张勇

    2013-01-01

      报道了二正丁胺沉淀镁离子制备高纯度氢氧化镁粉体的方法,使用红外、热分析、X射线衍射表征了产物的纯度,使用扫描电镜观测了产物的表面形貌,对反应体系的热力学和动力学过程进行了研究。研究结果表明,所合成的氢氧化镁为片状结晶,具有结晶程度高、纯度高和粒度小的优点。该方法可控程度高,镁离子沉淀效率高,胺用量小,与氨法相比具有明显的优势,为氢氧化镁的合成提供了一种可行性高、工艺简单、条件温和的绿色化学方法。%  A method for preparing high pure Mg(OH)2 powders was reported by di-n-butylamine precipitating Mg2+. The purity was measured by FT-IR, TG and XRD, the surface topography was analyzed by SEM. The thermodynamic and kinetic process of reaction system was also discussed. The results showed that the magnesium hydroxide powders were flaky crystal with high purity, high crys-tallinity and smaller size. This method could be well controlled which provided a high feasibility, simple technology, green chemistry and mild conditions for the synthesis of magnesium hydroxide. Compared with ammonia method, this method had obvious advan-tages of high precipitation efficiency and little amine consumption.

  20. I study of the quality of the welded unions for the method of orbital welding in atmosphere of argon of high purity subjected to reiterated repairs

    International Nuclear Information System (INIS)

    In the assembly of the facilities of the industry doctor - pharmacist, biotechnical and nutritious it is broadly used the method of orbital welding in atmosphere of argon of high of high purity. The repairs of the welded unions carried out by this method in these industries are very limited and they should be carried out alone as exceptional cases. In the work the results are exposed when evaluating the quality of the welding obtained with lack of coalition and that they were subjected to reiterated repairs. In the same one the one settles down procedure that allows to carry out a number of up to three repairs without the is affected quality of the welded unions. They are also picked up in this work the experiences reached by the Cuban specialists in the one employment of machines of orbital welding in the construction of technological systems of the industry bio pharmaceutic

  1. THE STUDY OF MANUFACTURE PROCESS OF HIGH PURITY H2WO4 POWDER%高纯粉状钨酸制备工艺的研究

    Institute of Scientific and Technical Information of China (English)

    李玲

    2000-01-01

    APT在水中的难溶性使得酸分解APT制取钨酸的化学反应成为固-液反应,从而妨碍了反应均匀有效地进行。在本文所述的研究中,通过将APT热离解为偏钨酸铵而显著地改善了原料的水溶解性,使得反应成为近似液-液反应。本文还着重讨论了诸如溶浆温度、酸用量、保温时间、陈化时间等工艺参数对酸分解的影响。就以杂质含量很低的APT为原料生产高纯钨酸,确立了相应的工艺参数。在所拟工艺条件下制得的高纯钨酸,纯度>99.99%,平均粒度0.61μm。操作简便、工艺稳定、产品转化率高,易实现工业化。%Because ammonium paratungstate (APT) is difficult to dissolve in water,the chemical reaction of acid decomposition APT to H2WO4 is solid-liquid reaction and hinder the reaction uniformly and effectively carrying on. 牋牋營n this paper,the material's dissolvability is marktedly improved by hot-decomposition APT to ammonium metatung tate (AMT) and make the acid decomposition reaction an approximate liquid-liquid reaction. 牋牋燱e discussed the effect of process parameters such as dissolution temperature ,acid volume ,holding heat times and laying times atc on acid decomposition and use low impurity content APT to produce high-purity H2WO4,and establish its process parameters under the drafting process condition to obtain high purity H2WO4 with purity?99.99? and 0.61祄 average particle size. This process has unsophisticated and stable operation,high-product conversion rate and commerial production.

  2. Performance comparison of AlTiC and AlTiB master alloys in grain refinement of commercial and high purity aluminum

    Institute of Scientific and Technical Information of China (English)

    LI Jian-guo; HUANG Min; MA Mo; YE Wei; LIU Dong-yu; SONG Dong-ming; BAI Bing-zhe; FANG Hong-sheng

    2006-01-01

    For further knowledge about the refining performance of AlTiC master alloys, Al5.5Ti0.25C and Al6.5Ti0.5C master alloys containing high Ti and C content were prepared and used in grain refining experiments of 99.8% commercial pure aluminum(CPAl). Their performance was compared with two types of Al5TilB refiners whose performance was nowadays considered to be the best. These two types of master alloys show similar refining efficiency at the addition level of 0.2%. However, at the addition level of 0.5%, there still exists great performance difference between AlTiC and Al5TiB alloys in grain refinement of 99.98% and 99.995% high purity aluminum(HPAl). The growth of columnar grains is fully suppressed due to the refinement of AlTiC at the addition level of 0.5%. Also, at the same addition level, the grain refining experiments of Al3Ti0.15C and Al5Ti0.2C master alloys which have found initial commercial applications are conducted in the above-mentioned three types of pure aluminum.According to the experimental results, these two refiners of different compositions are both nonideal. The second phase particles extracted from each refiner were observed through TEM, while the nuclei of grains after grain refinement were observed through SEM. The results were analyzed through computation and comparison of the constitutional-supercooling parameter and the growth-restriction parameter whose values were determined by solute element in aluminum melt with different purity. Apparently,AlTiC master alloys with high content of Ti and C element have great refining potential.

  3. Calculation of the photoelectric efficiency with Monte Carlo method of a planar high purity Ge detectors and application to cross sections measurement

    International Nuclear Information System (INIS)

    The aim of this work is to elaborate a Monte Carlo programme which calculate the photoelectric efficiency of a planar high purity Ge detector for low energy photons. This programme calculate the auto absorption, the absorption in different media crossed by the photon and the intrinsic and total efficiencies. The results of this programme were very satisfactory since they reproduce the measured values in the two different cases of punctual and volumic sources. The result of the photoelectric efficiency calculation with this programme has been applied to determine the cross section of the 166-Er (n,2 n) 165-Er reaction induced by 14 MeV neutron, where only the measurement by x spectrometry is possible. The value obtained is concordant with the data given by the literature. 119 figs., 39 tabs., 96 refs. (F.M.)

  4. Signal modeling of high-purity Ge detectors with a small read-out electrode and application to neutrinoless double beta decay search in Ge-76

    CERN Document Server

    Agostini, M; Budjá\\vs, D; Bellotti, E; Brugnera, R; Cattadori, C M; di Vacri, A; Garfagnini, A; Pandola, L; Schönert, S

    2010-01-01

    The GERDA experiment searches for the neutrinoless double beta decay of Ge-76 using high-purity germanium detectors enriched in Ge-76. The analysis of the signal time structure provides a powerful tool to identify neutrinoless double beta decay events and to discriminate them from gamma-ray induced backgrounds. Enhanced pulse shape discrimination capabilities of "Broad Energy Germanium" detectors with a small read-out electrode have been recently reported. This paper describes the full simulation of the response of such a detector, including the Monte Carlo modeling of radiation interaction and subsequent signal shape calculation. A pulse shape discrimination method based on the ratio between the maximum current signal amplitude and the event energy applied to the simulated data shows quantitative agreement with the experimental data acquired with calibration sources. The simulation has been used to study the survival probabilities of the decays which occur inside the detector volume and are difficult to asse...

  5. Integrated Approach To Producing High-Purity Trehalose from Maltose by the Yeast Yarrowia lipolytica Displaying Trehalose Synthase (TreS) on the Cell Surface.

    Science.gov (United States)

    Li, Ning; Wang, Hengwei; Li, Lijuan; Cheng, Huiling; Liu, Dawen; Cheng, Hairong; Deng, Zixin

    2016-08-10

    An alternative strategy that integrated enzyme production, trehalose biotransformation, and bioremoval in one bioreactor was developed in this study, thus simplifying the traditional procedures used for trehalose production. The trehalose synthase gene from a thermophilic archaea, Picrophilus torridus, was first fused to the YlPir1 anchor gene and then inserted into the genome of Yarrowia lipolytica, thus yielding an engineered yeast strain. The trehalose yield reached 73% under optimal conditions. The thermal and pH stabilities of the displayed enzyme were improved compared to those of its free form purified from recombinant Escherichia coli. After biotransformation, the glucose byproduct and residual maltose were directly fermented to ethanol by a Saccharomyces cerevisiae strain. Ethanol can be separated by distillation, and high-purity trehalose can easily be obtained from the fermentation broth. The results show that this one-pot procedure is an efficient approach to the economical production of trehalose from maltose. PMID:27472444

  6. Possible influence of surface oxides on the optical response of high-purity niobium material used in the fabrication of superconducting radio frequency cavity

    Science.gov (United States)

    Singh, Nageshwar; Deo, M. N.; Roy, S. B.

    2016-09-01

    We have investigated the possible influence of surface oxides on the optical properties of a high-purity niobium (Nb) material for fabrication of superconducting radio frequency (SCRF) cavities. Various peaks in the infrared region were identified using Fourier transform infrared and Raman spectroscopy. Optical response functions such as complex refractive index, dielectric and conductivity of niobium were compared with the existing results on oxides free Nb and Cu. It was observed that the presence of a mixture of niobium-oxides, and probably near other surface impurities, appreciably influence the conducting properties of the material causing deviation from the typical metallic characteristics. In this way, the key result of this work is the observation, identification of vibrational modes of some of surface complexes and study of its influences on the optical responses of materials. This method of spectroscopic investigation will help in understanding the origin of degradation of performance of SCRF cavities.

  7. Methods for solving several technical problems during designing a set of low background anti-compton high purity germanium gamma-ray spectrograph

    International Nuclear Information System (INIS)

    Several methods are introduced for solving some technical problems of a set of high purity Germanium (HPGe) anti-Compton low background gamma ray spectrograph, including mainly the manufacturing and recreating of screened room, the design of main detector elevating device, the improvement of working stability, the alignment of anti-coincidence system, the scaling of spectrograph, and the measuring of samples, etc. The main technical indexes are: energy resolution FWHM = 1.77 keV (1332.5 keV), peak-Compton ratio 694:1 (662 keV), Compton integral suppression coefficient 3.8(137Cs 50∼595 keV), relative detecting efficiency 38.3% (1332.5 keV), system background 0.39 s-1(50∼2014 keV), and drift less than 0.07% under the gain of 1332.5 keV with stable zero point are obtained after 48 hours continuous working

  8. Synthesis of 195mPt radiolabelled cis-diamminedichloroplatinum(II) of high chemical and radiochemical purity using high performance liquid chromatography

    International Nuclear Information System (INIS)

    An improved method is described for the synthesis of 195mPt-radiolabelled cis-diamminedichloroplatinum(II). An amount of 10 mg of 95% enriched 194Pt was irradiated for 75 h in the hydraulic conveyer of the Kyoto University Reactor at a thermal neutron flux of approximately 8.15x1013 n.cm-2.sec-1 and the 195mPt-radiolabelled CDDP was purified using HPLC. The chemical yield is 61%, chemical purity is greater than 99.74%, the radiochemical purity is nearly 100%, and the specific activity is 7.4x106 Bq mg-1 CDDP (200 μCi mg-1 CDDP). (author) 9 refs.; 5 figs.; 1 tab

  9. 高纯乙腈连续精馏过程建模与分析%Modeling and analyzing of continuous process for rectifying high purity acetonitrile

    Institute of Scientific and Technical Information of China (English)

    曾涵卫; 孙小方; 蔡亦军; 夏陆岳; 周猛飞; 潘海天

    2012-01-01

    Based on the deep analysis of continuous process of rectifying high purity acetonitrile and its mechanics, with rational assumptions dynamic mathematical models of multi - tower for rectifying high purity acetonitrile were established by material balance, energy balance, environmental impact and hydraulic analysis, considering the character of multi-stage cascade and the difficulty of operating conditions optimization. Furthermore, the dynamic simulation and analysis were carried out respectively to the dealcoholization tower, vacuum tower and pressure tower. Simultaneously, investigating the tower pressure and steam heating effect on the separation process, and finding the further relative dynamic data of acetonitrile could provide a good foundation for the research of system integration optimization and control.%针对高纯乙腈连续精馏过程多塔串级及操作条件优化困难等特点,在深入分析乙腈连续精馏工艺流程及机理基础上,通过物料衡算、能量衡算、环境影响衡算和水力学分析等原理,结合必要的合理假设,建立乙腈连续精馏多塔的动态数学模型,对脱醇塔、减压塔和加压塔分别进行动态模拟和分析,考察塔内压力、加热蒸汽量等对分离过程的影响,并进一步寻找这些因素对出料乙腈的动态变化数据,为实施系统的集成优化与控制提供了良好基础.

  10. Monte Carlo simulation of gamma-ray interactions in an over-square high-purity germanium detector for in-vivo measurements

    Science.gov (United States)

    Saizu, Mirela Angela

    2016-09-01

    The developments of high-purity germanium detectors match very well the requirements of the in-vivo human body measurements regarding the gamma energy ranges of the radionuclides intended to be measured, the shape of the extended radioactive sources, and the measurement geometries. The Whole Body Counter (WBC) from IFIN-HH is based on an “over-square” high-purity germanium detector (HPGe) to perform accurate measurements of the incorporated radionuclides emitting X and gamma rays in the energy range of 10 keV-1500 keV, under conditions of good shielding, suitable collimation, and calibration. As an alternative to the experimental efficiency calibration method consisting of using reference calibration sources with gamma energy lines that cover all the considered energy range, it is proposed to use the Monte Carlo method for the efficiency calibration of the WBC using the radiation transport code MCNP5. The HPGe detector was modelled and the gamma energy lines of 241Am, 57Co, 133Ba, 137Cs, 60Co, and 152Eu were simulated in order to obtain the virtual efficiency calibration curve of the WBC. The Monte Carlo method was validated by comparing the simulated results with the experimental measurements using point-like sources. For their optimum matching, the impact of the variation of the front dead layer thickness and of the detector photon absorbing layers materials on the HPGe detector efficiency was studied, and the detector’s model was refined. In order to perform the WBC efficiency calibration for realistic people monitoring, more numerical calculations were generated simulating extended sources of specific shape according to the standard man characteristics.

  11. Kinetic and microstructural studies of thermal decomposition in uranium mononitride compacts subjected to heating in high-purity helium

    Science.gov (United States)

    Lunev, A. V.; Mikhalchik, V. V.; Tenishev, A. V.; Baranov, V. G.

    2016-07-01

    Although uranium mononitride has a high melting point (≈3100 K), it often decomposes well below this temperature. The threshold and kinetics of thermal decomposition depend on samples' chemical content and on gas environment. However, most experiments with uranium nitride samples were done so far in vacuum conditions and did not allow thorough examination of reaction kinetics at high temperatures. This research focuses on studying the different stages of thermal decomposition in uranium nitride samples subjected to heating in helium. Mass loss and thermal effects are identified with simultaneous thermal analysis (STA), while scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to register phase and compositional changes. Thermal decomposition in uranium nitride samples is found to be a multi-stage process with the final stage characterized by uranium vaporization. The results are useful for estimating the high-temperature behaviour of uranium nitride fuel during its fabrication and performance in some of Gen IV reactors.

  12. The production of ultra-high purity single isotopes or tailored isotope mixtures by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Liezers, Martin; Farmer, Orville T.; Dion, Michael P.; Thomas, Linda MP; Eiden, Gregory C.

    2015-01-01

    We report the development and testing of a simple collector arrangement for a commercial quadrupole ICP-MS that for the first time has been used to produce small quantities of highly enriched (>99.99%) single isotopes, with deposition rates >10 ng/hour. The collector assembly replaces the standard instrument detector allowing for implantation with simultaneous monitoring of the incident ion current. Even under zero bias implant conditions, low energy (<10 eV), ion collection efficiency was observed to be very high ~99%. 151Eu ion currents of 0.1-0.5 nA were collected on a simple, planar foil without resorting to any type of cup configuration. Recovery of the enriched isotope from such foils is much simpler than from a more complex cup configuration. High rejection of adjacent mass isotopes was demonstrated by selectively implanting 167Er without any discernible co-implantation of 166Er and 168Er. The important analytical possibilities of the new approach to isotope ratio measurement, tracer purification and radiation measurements are discussed.

  13. Improving efficiency and color purity of poly(9,9-dioctylfluorene) through addition of a high boiling-point solvent of 1-chloronaphthalene.

    Science.gov (United States)

    Liang, Junfei; Yu, Lei; Sen Zhao; Ying, Lei; Liu, Feng; Yang, Wei; Peng, Junbiao; Cao, Yong

    2016-07-15

    In this work, the β-phase of poly(9,9-dioctylfluorene) (PFO) was used as a probe to study the effects of the addition of a high boiling-point solvent of 1-chloronaphthalene on the nanostructures and electroluminescence of PFO films. Both absorption and photoluminescence spectra showed that the content of the β-phase in PFO film was obviously enhanced as a result of the addition of a small amount of 1-chloronaphthalene into the processing solvent of p-xylenes. Apparently rougher morphology associated with the effectively enhanced ordering of polymer chains across the entire film was observed for films processed from p-xylene solutions consisting of a certain amount of 1-chloronaphthalene, as revealed by atomic force microscopy and grazing incidence x-ray diffraction measurements. In addition to the effects on the nanostructures of films, of particular interest is that the performance and color purity of polymer light-emitting devices can be noticeably enhanced upon the addition of 1-chloronaphthalene. These observations highlight the importance of controlling the nanostructures of the emissive layer, and demonstrate that the addition of a low volume ratio of high boiling-point additive can be a promising strategy to attain high-performance polymer light-emitting diodes. PMID:27250786

  14. Improving efficiency and color purity of poly(9,9-dioctylfluorene) through addition of a high boiling-point solvent of 1-chloronaphthalene

    Science.gov (United States)

    Liang, Junfei; Yu, Lei; Zhao, Sen; Ying, Lei; Liu, Feng; Yang, Wei; Peng, Junbiao; Cao, Yong

    2016-07-01

    In this work, the β-phase of poly(9,9-dioctylfluorene) (PFO) was used as a probe to study the effects of the addition of a high boiling-point solvent of 1-chloronaphthalene on the nanostructures and electroluminescence of PFO films. Both absorption and photoluminescence spectra showed that the content of the β-phase in PFO film was obviously enhanced as a result of the addition of a small amount of 1-chloronaphthalene into the processing solvent of p-xylenes. Apparently rougher morphology associated with the effectively enhanced ordering of polymer chains across the entire film was observed for films processed from p-xylene solutions consisting of a certain amount of 1-chloronaphthalene, as revealed by atomic force microscopy and grazing incidence x-ray diffraction measurements. In addition to the effects on the nanostructures of films, of particular interest is that the performance and color purity of polymer light-emitting devices can be noticeably enhanced upon the addition of 1-chloronaphthalene. These observations highlight the importance of controlling the nanostructures of the emissive layer, and demonstrate that the addition of a low volume ratio of high boiling-point additive can be a promising strategy to attain high-performance polymer light-emitting diodes.

  15. Design, fabrication, performance and reliability of Pt- and RuO2-coated microrelays tested in ultra-high purity gas environments

    Science.gov (United States)

    de Boer, M. P.; Czaplewski, D. A.; Baker, M. S.; Wolfley, S. L.; Ohlhausen, J. A.

    2012-10-01

    We have fabricated, tested and analyzed the reliability of Pt- and RuO2-coated ohmic microrelays in ultra-high purity gas environments. RuO2-coated relays could survive 3 × 108 contact cycles without electrical degradation, while Pt-coated devices degraded after 105 cycles. Thermally actuated microrelays were fabricated using a process that employed a polysilicon surface-micromachined substructure. After releasing the devices, just a few blanket metal depositions were required to create the different coatings. This method allowed direct comparisons between different coating materials, and was enabled by a self-aligned shadow mask that provides electrical isolation between different traces. Testing was performed in a clean environment achieved through in situ ultra-high vacuum bakeouts, chamber cooling to real contact versus non-contacting areas, implying that carbon did not play a role in limiting the switches’ reliability. The Pt-coated switch reliability limit was attributed to surface wear rather than to the growth of a contaminating film. For the RuO2 switches, trace resistance was reduced by ten times using an Al underlayer, so that the total device resistance was compatible with commercial device requirements. Because RuO2 is expected to be resistant to hydrocarbon contamination, this work shows that the RuO2 coating provides a promising path toward achieving ultra-high reliability ohmic microswitches.

  16. Thermal Photons From Magnetized Bare Strange Stars

    CERN Document Server

    Méndez, Enrique Moreno; Patiño, Leonardo; Ortega, Patricia

    2013-01-01

    A plasma made out of strange-quark matter (SQM) and electrons, has a rather high plasma frequency (>20 MeV). Thus, a compact star made of such material all the way up to its surface, i.e., a bare strange star, would be unable to radiate away its thermal emission. We use the MIT-bag model and assume that SQM is the ground state of nuclear matter at high density. We investigate whether the presence of a magnetic field will allow propagation of radiation at frequencies below the SQM plasma frequencies. Hence, we study the presence of gyrofrequencies in a SQM plasma permeated by a strong magnetic field (B > 10^{12} G). We find that small regions in the frequency spectrum allow radiation propagation due to the presence of the magnetic fields. It is likely that narrow bands of radiation would likely be observable from magnetized bare strange stars .

  17. Synthesis of high-purity precipitated calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

    Science.gov (United States)

    de Beer, M; Doucet, F J; Maree, J P; Liebenberg, L

    2015-12-01

    We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. production of high-grade CaCO3 (i.e. >99 mass% as CaCO3) or precipitated calcium carbonate (PCC). The process used an acid gas (H2S) to improve the aqueous dissolution of CaS, which is otherwise poorly soluble. The carbonate product was primarily calcite (99.5%) with traces of quartz (0.5%). Calcite was the only CaCO3 polymorph obtained; no vaterite or aragonite was detected. The product was made up of micron-size particles, which were further characterised by XRD, TGA, SEM, BET and true density. Results showed that about 0.37 ton of high-grade PCC can be produced from 1.0 ton of gypsum waste, and generates about 0.19 ton of residue, a reduction of 80% from original waste gypsum mass to mass of residue that needs to be discarded off. The use of gypsum waste as primary material in replacement of mined limestone for the production of PPC could alleviate waste disposal problems, along with converting significant volumes of waste materials into marketable commodities. PMID:26316100

  18. Wet chemical treatments of high purity Ge crystals for γ-ray detectors: Surface structure, passivation capabilities and air stability

    Energy Technology Data Exchange (ETDEWEB)

    Carturan, S., E-mail: carturan@lnl.infn.it [Department of Physics and Astronomy, University of Padova, Padova (Italy); INFN, Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Maggioni, G. [Department of Physics and Astronomy, University of Padova, Padova (Italy); INFN, Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Rezvani, S.J. [Department of Physics, University of Camerino, Camerino, Macerata (Italy); Gunnella, R. [Department of Physics, University of Camerino, Camerino, Macerata (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pinto, N. [Department of Physics, University of Camerino, Camerino, Macerata (Italy); INFN, Sezione di Perugia, Perugia (Italy); Gelain, M. [Department of Physics and Astronomy, University of Padova, Padova (Italy); INFN, Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Napoli, D.R. [INFN, Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy)

    2015-07-01

    Aiming at the production of HPGe diodes for γ-ray detection, surface passivation of the pristine Germanium surface is pursued by treatment of freshly etched, highly reactive Ge (100) surface by different chemicals, to obtain chemisorbed species with sufficient insulating properties for allowing high voltage application (up to 1100 V) with low leakage currents (lower than 30 pA). (100) surface termination of Ge crystal with hydride, methoxide, and sulphide is carried out by wet chemical treatments using suitable reactants. The chemical composition of the newly formed monolayers is investigated with regards to the nature of chemical bonding with Ge atop atoms. To this aim Fourier Transform Infrared Spectrometry (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were used; the performance as dielectric layer of each native Ge compound/complex is measured directly from I–V measurements of a HPGe diode. Atomic stability of each surface layer is monitored detecting structural changes after air exposure by XPS and FTIR spectroscopies and by relevant leakage current variations. - Highlights: • Different surface passivations were applied to HPGe by wet chemical methods. • New chemical bonds were characterized by FTIR and XPS. • Air stability: hydride and sulphide treatments display the best oxidation resistance. • I–V measurements: all the treatments provided efficient passivation.

  19. Determination of the efficiency of high purity germanium and silicon diode detectors for improved assessment of emission spectra delivered by medical X-ray tubes

    International Nuclear Information System (INIS)

    X-ray sources are widely used in medicine: brachytherapy, radiodiagnosis, mammography and contact radiotherapy. Kerma in air is the primary quantity measured to determine the dose to the patient. Accurate air kerma assessment is obtained using correction factors calculated using the emission spectrum. The Laboratoire National Henri Becquerel launched an in-depth study of the spectral emission of its reference X-ray beams used in dosimetry. Two semiconductor detectors are discussed here: a High-Purity germanium and a silicon PiN, both cooled and operated with dedicated electronics and software. In the low energy range (E≤50 keV), those spectrometers are complementary but require a careful calibration to deduce the emitted spectrum from the detected one. Indeed, both detectors were characterized in terms of spectral response and intrinsic efficiency using a tuneable monochromatic X-ray source (SOLEX at CEA Saclay) in the 5- to 20-keV energy range and various radionuclides. The characterization methods and results, including the first measured spectra of medical X-ray tubes (high voltage≤50 kV), are presented in this work. This paper presents the first step of a broader project, aiming at assessing the emission spectrum independently of the detector choice. (authors)

  20. NAA and low-background Υ- spectrometry for the analysis of U and Th in high purity silica used in electronic devices

    International Nuclear Information System (INIS)

    It has been established that soft error of high precision electronic circuits can be induced by alpha particle emitted from the naturally occurring radioactive impurities such as U and Th. Silica has used in electronic industries as the base materials and impurities must be controlled strictly. Recently, electronic circuits have become lower dimension and higher density, so alpha-particle emitting radioactive impurities have to be strictly controlled. The objective of the present study was to develop of NAA and gamma-spectrometry for the sensitive (ng/g) and precise analysis of U and Th. A new NAA method has been established using the HTS irradiation facility which has been used to produce radioisotopes for industries and medicines. When the ultratrace impurities have to be analyzed by NAA, background gamma-ray spectra induced from 222Rn and its progeny nuclides in atmosphere are serious problem. This unstable background was eliminated and stabilized by the use of a nitrogen purging system. By the use of HTS-NAA and low background gamma-spectrometry ultratrace amounts of U (0.1ng/g) and Th (0.01ng/g) in high purity silica could be analyzed

  1. 鹅肝细胞的高纯分离及培养%Isolation and culture of high-purity goose hepatocytes

    Institute of Scientific and Technical Information of China (English)

    洪胜辉; 张军; 邵丹; 张宜辉; 张蕊; 王来娣; 龚道清

    2012-01-01

    Using the simple method of collagenase digestion directly'to isolate goose embryo hepatocytes and can acquire a large high viability and high purity of hepatocytes. HE dyed showed that mostly hepatocytes have two or more nucleus which demonstrate cells have strong proliferation split ability . The specific gene albumin gene test showed that isolated cells are mature hepatocytes. It is a easily and effective method which can get primary goose hepatocyte.%采用简单的"胶原酶直接消化法"分离鹅胚胎肝细胞,得到的肝细胞纯度高,活性好;HE染色显示大量双核或多核细胞,细胞具有旺盛增殖分裂能力;肝脏特异性基因白蛋白基因检测显示所分离细胞为成熟肝脏细胞。该法操作简单、高效,是获得鹅原代肝细胞的一种较好的方法,有利于以鹅原代肝细胞为模型的体外研究工作的开展。

  2. Study on the Synthesis of High Purity Tetrahydrolinalool%高纯四氢芳樟醇的研究

    Institute of Scientific and Technical Information of China (English)

    张忠富; 张琦

    2013-01-01

    Under certain conditions,linalool can be high-selectively hydrogenated to tetrahydrolinalool.The selectivity depended on the characteristic of catalyst,hydrogenation temperature and source of linalool.Under a suitable hydrogen pressure,when changing the characteristic of catalyst,reaction temperature or source of linalool,the selectivity for tetrahydrolinalool can be improved.For example,when the synthetic linalool imported from Japan was used as raw material (98.7% by GC),and the catalyst was W-6-type Raney nickel,reaction temperature was (60 ± 10) ℃,hydrogen pressure was 1-3 MPa,the content of tetrahydrolinalool reached to 98.7% with selectivity of 100%.%在一定条件下,芳樟醇可高选择性地氢化成四氢芳樟醇,氢化选择性与催化剂的特性、氢化温度及芳樟醇来源有关.在适宜的氢压及搅拌条件下,改变催化剂的特性、反应温度及使用不同来源的芳樟醇能提高加氢产物中四氢芳樟醇的含量.以日本进口的合成芳樟醇(含量98.7%)为原料,采用W-6型雷尼镍为催化剂,在(60±10)℃、1~3 MPa氢压的条件下进行氢化,所得四氢芳樟醇含量为98.7%,选择性为100%.

  3. 合成高纯度丙交酯的方法改进%Process Improvement on the Synthesis of Lactide with High Purity

    Institute of Scientific and Technical Information of China (English)

    唐拾贵; 蒋云晨; 孙雁龙; 叶飞; 郭凯

    2012-01-01

    Lactide(l) with high purity was synthesized from D,L-lactic acid(2) using 1,4-dewate-ring orbital fixed carboxyl group by stannous octanoate-catalyzed polymerization to give low poly( lactic acid) (5) and then pyrolysis 5. The optimum reaction conditions were as follows; 2 was 960 mmol,n (OH) : n(2) was 1:15,stannous octanoate was 1 % mass of 2,under 3. 0 kPa from 90 X heating to 160.0℃(2.0h),under 0.5 kPa from 160 X heating to 180.0℃(0.5h),reacted at 180.0℃ for 5.0 h to give 5; cracking from 180. 0 ℃gradually heating to 230. 0℃,to collect fraction between 180. 0℃ ~ 230.0℃ to obtain 1 in yield of 96.1% with purity of 97. 5% .%用1,4-去水山梨醇固定羧基,D,L-乳酸(2)经催化聚合制得低聚乳酸(5);5经热裂解合成了丙交酯(3).最佳反应条件为:2 960 mmol,n(OH)∶n(2) =1∶15,辛酸亚锡1.2%(以2质量计算),在3.0 kPa下由90℃升温至160.0℃(2.0 h);在0.4 kPa下由160℃升温至180.0℃(0.5 h),于180.0℃反应5.0h制得5;由180.0℃逐渐升温至230.0℃进行5的裂解反应,收集180.0℃~230.0℃馏分得1,收率96.1%,纯度97.5%.

  4. 电解电容器高压阳极用高纯铝箔再结晶组织研究%Study on recrystallization texture of high purity aluminum foil for electrolytic capacitor

    Institute of Scientific and Technical Information of China (English)

    王傲冰; 黄丽颖; 丛福官; 单长智

    2009-01-01

    利用Axiovert 25型金相显微镜对高纯铝箔制备过程中的组织进行了观察和分析.结果表明,轧制变形量越大,高纯铝箔的再结晶组织越细小;高纯铝箔的再结晶过程经历了回复、再结晶和晶粒长大三个阶段;高纯铝箔开始再结晶温度在200℃~230℃之间.%In this paper, Axiovert 25 type metallographic microscope was used to observe and analyze the preparation process of high-purity aluminum foils.The results showed that the greater the rolling deformation rate, the smaller of the recrystallization texture of high purity aluminum foil. The recrystallization process of high purity aluminum foil experienced three stages: reply, recrystallization and grain growth. Beginning recrystallization temperature of high purity aluminum foil is 200℃-230℃.

  5. Genotypic and phenotypic diversity of Ralstonia pickettii and Ralstonia insidiosa isolates from clinical and environmental sources including High-purity Water.

    LENUS (Irish Health Repository)

    Ryan, Michael P

    2011-08-30

    Abstract Background Ralstonia pickettii is a nosocomial infectious agent and a significant industrial contaminant. It has been found in many different environments including clinical situations, soil and industrial High Purity Water. This study compares the phenotypic and genotypic diversity of a selection of strains of Ralstonia collected from a variety of sources. Results Ralstonia isolates (fifty-nine) from clinical, industrial and environmental origins were compared genotypically using i) Species-specific-PCR, ii) PCR and sequencing of the 16S-23S rRNA Interspatial region (ISR) iii) the fliC gene genes, iv) RAPD and BOX-PCR and v) phenotypically using biochemical testing. The species specific-PCR identified fifteen out of fifty-nine designated R. pickettii isolates as actually being the closely related species R. insidiosa. PCR-ribotyping of the 16S-23S rRNA ISR indicated few major differences between the isolates. Analysis of all isolates demonstrated different banding patterns for both the RAPD and BOX primers however these were found not to vary significantly. Conclusions R. pickettii species isolated from wide geographic and environmental sources appear to be reasonably homogenous based on genotypic and phenotypic characteristics. R. insidiosa can at present only be distinguished from R. pickettii using species specific PCR. R. pickettii and R. insidiosa isolates do not differ significantly phenotypically or genotypically based on environmental or geographical origin.

  6. Simultaneous determination of some trace metal impurities in high-purity sodium tungstate using coprecipitation and inductively coupled plasma atomic emission spectrometry

    Institute of Scientific and Technical Information of China (English)

    MA Xiaoguo; KUANG Tongchun; LIU Qianjun

    2004-01-01

    A method based on the combination of coprecipitation with inductively coupled plasma atomic emission spec trometry (ICP-AES) was developed for the determination of impurities in high-purity sodium tungstate. Six elements (Co,Cu, Fe, Mn, Ni, and Pb) were coprecipitated by lanthanum hydroxide so as to be concentrated and separated from the tungsten matrix. Effects of some factors on the recoveries of the analytes and on the residual amount of sodium tungstate were investigated, and the optimum conditions for the coprecipitation were proposed. Matrix-matching calibration curve method was used for the analysis. It is shown that the elements mentioned above can be quantitatively recovered. The detection limits for Co, Cu, Fe, Mn, Ni, and Pb are 0.07, 0.4, 0.2, 0.1, 0.6, and 1.3 μg.g-1, respectively. The recoveries vary from 92.5% to 108%, and the relative standard deviations (RSDs) are in the range of 3.1%-5.5%.

  7. Heterogeneous nucleation of entrained eutectic Si in high purity melt spun Al-Si alloys investigated by entrained droplet technique and DSC

    Science.gov (United States)

    Li, J. H.; Albu, M.; Ludwig, T. H.; Hofer, F.; Arnberg, L.; Schumacher, P.

    2016-03-01

    Entrained droplet technique and DSC analyses were employed to investigate the influence of trace elements of Sr, Eu and P on the heterogeneous nucleation of entrained eutectic Si in high purity melt spun Al-5wt.% Si alloys. Sr and Eu addition was found to exert negative effects on the nucleation process, while an increased undercooling was observed. This can be attributed to the formation of phosphide compounds having a lower free energy and hence may preferentially form compared to AlP. Only a trace P addition was found to have a profound effect on the nucleation process. The nucleation kinetics is discussed on the basis of the classical nucleation theory and the free growth model, respectively. The estimated AlP patch size was found to be sufficient for the free growth of Si to occur within the droplets, which strongly indicates that the nucleation of Si on an AlP patch or AlP particle is a limiting step for free growth. The maximum nucleation site density within one droplet is directly related to the size distribution of AlP particles or AlP patches for Si nucleation, but is independent of the cooling rates. Although the nucleation conditions were optimized in entrained droplet experiments, the observed mechanisms are also valid at moderate cooling conditions, such as in shape casting.

  8. Firewalls From Double Purity

    CERN Document Server

    Bousso, Raphael

    2013-01-01

    The firewall paradox is often presented as arising from double entanglement, but I argue that more generally the paradox is double purity. Near-horizon modes are purified by the interior, in the infalling vacuum. Hence they cannot also be pure alone, or in combination with any third system, as demanded by unitarity. This conflict arises independently of the Page time, for entangled and for pure states. It implies that identifications of Hilbert spaces cannot resolve the paradox. Traditional complementarity requires the unitary identification of infalling matter with a scrambled subsystem of the Hawking radiation. Extending this map to the infalling vacuum overdetermines the out-state. More general complementarity maps ("A=R_B", "ER=EPR") founder when the near-horizon zone is pure. I argue that pure-zone states span the microcanonical ensemble, and that this suffices to make the horizon a special place. I advocate that the ability to detect the horizon locally, rather than the degree or probability of violence...

  9. Firewalls from double purity

    Science.gov (United States)

    Bousso, Raphael

    2013-10-01

    The firewall paradox is often presented as arising from double entanglement, but I argue that more generally the paradox is double purity. Near-horizon modes are purified by the interior, in the infalling vacuum. Hence, they cannot also be pure alone, or in combination with any third system, as demanded by unitarity. This conflict arises independently of the Page time, for entangled and for pure states. It implies that identifications of Hilbert spaces cannot resolve the paradox. Traditional complementarity requires the unitary identification of infalling matter with a scrambled subsystem of the Hawking radiation. Extending this map to the infalling vacuum overdetermines the out-state. More general complementarity maps (“A=RB,” “ER=EPR”) necessarily fail when the near-horizon zone is pure. I argue that pure-zone states span the microcanonical ensemble, and that this suffices to make the horizon a special place. I advocate that the ability to detect the horizon locally, rather than the degree or probability of violence, is what makes firewalls problematic. Conversely, if the production of matter at the horizon can be dynamically understood and shown to be consistent, then firewalls do not constitute a violation of the equivalence principle.

  10. Measurement of terrestrial gamma radiation dose-rate (TGRD) level in soil samples from the district of Rembau, Malaysia, using high-purity Germanium detectors

    International Nuclear Information System (INIS)

    This study assesses the gamma radiation levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected from the district of Rembau, Malaysia using High-purity Germanium (HPGe) Detectors. A 105 measurement were performed on surface soil using NaI (Tl) gamma-ray detector with crystal size 1x1, covering about 83% land of the Rembau district. The concentration of the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected were determined by using HPGe detector based on high-resolution gamma spectrometry system at Malaysia Nuclear Agency. The range of natural gamma radiation measured was from 114±14 nGy h−1 to 857±14 nGy h−1. The range of activity concentrations of U, Th and °K in soil from the studied areas varies from 151-401 Bq kg−1, 113-342 Bq kg−1 and 674-1526 Bq kg−1 with mean values of 245 Bq kg−1, 186 Bq kg−1 and 1152 Bq kg1 respectively. The mean values of terrestrial gamma radiation dose rate measured in Rembau district is 383±18 nGy h−1 compared to the Malaysian average is 92 nGy h−1 and world average is 59 nGy h−1 (UNSCEAR, 2000). The average annual dose from such terrestrial gamma radiation dose rates to an individual in Rembau district, assuming a tropical rural setting is estimated to be 0.78 mSv per year, which is considered to be within the normal range for doses from natural sources. An isodose map for the Rembau district has been plotted

  11. Preparation of High-purity Silica White Using Micro-silica Powder%微硅粉制取高纯白炭黑的工艺初探

    Institute of Scientific and Technical Information of China (English)

    李小英; 彭建蓉; 和晓才; 杨大锦

    2014-01-01

    Preparation of high-purity silica white by micro-silica powder roasting with alkaline clinker -leaching using water -solution purification -carbon dioxide decomposition -washing -calcination has been researched .The mixture of micro-silica powder with soda was roasted at 850 ℃ for 1 hour to prepare sodium metasilicate clinker .The clinker was leached with water at temperature of 70 ℃ ,then the impurity(Al ,Fe) in the leaching solution was removed with lime powder .Removal rate of Fe is 94% ,removal rate of Al is 56% ,the loss rate of SiO2 is 19% .The purified solution was carbon decomposition for 3-4 hours using CO2 to precipitate acid metasilicate at temperature of 50-60 ℃ , CO2 flow and air flow ratio of 1∶7 .0 -1∶7 .5 .The precipitated acid metasilicate was washed using hydrochloric acid and distilled water ,then was dried and calcined to obtain high-purity silica white with SiO2 grade over 99 .98% .For process ,the raw materials are readily available ,process is simple , no-pollution ,industrial silica powder can be fully used with high value .%研究了以微硅粉碱性焙烧-熟料浸出-溶液净化-碳分沉淀-洗涤-干燥-煅烧工艺制取白炭黑。将微硅粉与纯碱混合均匀,在850℃下焙烧1 h制成偏硅酸钠熟料;熟料水浸得偏硅酸钠溶液;偏硅酸钠溶液在水浴温度70℃下,用石灰粉搅拌净化1 h除杂,净化液中杂质Fe脱除率为94%,Al脱除率为56%,SiO2损失率为19%;净化液用CO2碳分沉淀,控制温度50~60℃,CO2流量与空气流量比为1∶7~1∶7.5,碳分时间3~4h,获得颗粒均匀的偏硅酸沉淀;偏硅酸经盐酸及蒸馏水洗涤后干燥煅烧得高纯白炭黑,白炭黑纯度在99.98%以上。此工艺原料易得,过程控制简单,不产生污染,可实现工业微硅粉的高值化利用。

  12. Water Accommodation on Bare and Coated Ice

    Science.gov (United States)

    Kong, Xiangrui

    2015-04-01

    A good understanding of water accommodation on ice surfaces is essential for quantitatively predicting the evolution of clouds, and therefore influences the effectiveness of climate models. However, the accommodation coefficient is poorly constrained within the literature where reported values vary by up to three orders of magnitude. In addition, the complexity of the chemical composition of the atmosphere plays an important role in ice phase behavior and dynamics. We employ an environmental molecular beam (EMB) technique to investigate molecular water interactions with bare and impurity coated ice at temperatures from 170 K to 200 K. In this work, we summarize results of water accommodation experiments on bare ice (Kong et al., 2014) and on ice coated by methanol (Thomson et al., 2013), butanol (Thomson et al., 2013) and acetic acid (Papagiannakopoulos et al., 2014), and compare those results with analogous experiments using hexanol and nitric acid coatings. Hexanol is chosen as a complementary chain alcohol to methanol and butanol, while nitric acid is a common inorganic compound in the atmosphere. The results show a strong negative temperature dependence of water accommodation on bare ice, which can be quantitatively described by a precursor model. Acidic adlayers tend to enhance water uptake indicating that the system kinetics are thoroughly changed compared to bare ice. Adsorbed alcohols influence the temperature dependence of the accommodation coefficient and water molecules generally spend less time on the surfaces before desorbing, although the measured accommodation coefficients remain high and comparable to bare ice for the investigated systems. We conclude that impurities can either enhance or restrict water uptake in ways that are influenced by several factors including temperature and type of adsorbant, with potential implications for the description of ice particle growth in the atmosphere. This work was supported by the Swedish Research Council and

  13. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  14. Environmentally assisted cracking and irradiation embrittlement of CF-8 and CF-8M cast austenitic stainless steels in high-purity water

    International Nuclear Information System (INIS)

    Cast austenitic stainless steels (CASS) are used for components with complex geometries in the cooling system of light water reactors (LWRs). Due to both thermal ageing and irradiation embrittlement, the long-term performance of CASS materials is of concern. To assess the impact of thermal ageing and irradiation embrittlement on the cracking behaviour of CASS materials, crack growth rate and fracture toughness JR curve tests were carried out on CF-8 and CF-8M compact-tension specimens in high-purity water with low dissolved oxygen. The as-received and thermally aged CASS specimens were irradiated to 0.08 dpa to investigate the combined effect of thermal ageing and neutron irradiation. The crack growth rates of irradiated CASS materials were compared with previous results on unirradiated specimens. While no elevated cracking susceptibility was observed for the irradiated specimens at this dose level, a slightly better corrosion fatigue performance was found in the CF-8 than in CF-8M materials. Thermal ageing history had little effect on the crack growth behaviour in the test environment. Trans-granular cleavage-like cracking was the main fracture mode in the crack growth rate tests, and delta ferrite morphology could be seen in some areas on the fracture surfaces. Compared to thermal ageing, neutron irradiation had a dominant role in the fracture toughness JR curve tests. The loss of toughness due to neutron irradiation was much more significant in the as-received than in the thermally aged CASS specimens. The fracture toughness of CASS specimens was reduced to a similar level after neutron irradiation regardless of their thermal ageing history. This suggests a more rapid development of embrittlement in the as-received than in the thermally aged CASS specimens under neutron irradiation. (authors)

  15. A radio-high-performance liquid chromatography dual-flow cell gamma-detection system for on-line radiochemical purity and labeling efficiency determination

    DEFF Research Database (Denmark)

    Lindegren, S; Jensen, H; Jacobsson, L

    2014-01-01

    In this study, a method of determining radiochemical yield and radiochemical purity using radio-HPLC detection employing a dual-flow-cell system is evaluated. The dual-flow cell, consisting of a reference cell and an analytical cell, was constructed from two PEEK capillary coils to fit into the w...

  16. 高纯度银杏黄酮的制备%Preparation of High-Purity Flavonoids from Ginkgo biloba L.

    Institute of Scientific and Technical Information of China (English)

    张伟; 李芊; 林炳昌

    2011-01-01

    [ Objective ] To prepare highly purified flavonoids of Ginkgo biloba L. , so as to explore a large - scale preparation process line of high purity flavonoids from Ginkgo biloba L.. [ Method ] Purified with chromatographic column with packing of ODS, effects of mobile phase ratio, concentration temperature and drying temperature on yield of flavonoids from Ginkgo biloba L. were investigated. [ Result] The optimum preparation conditions were as follows: target fraction of methanol to 0.5% phosphoric acid ratio of 5:5 and 7: 3, concentration temperature and drying temperature of 45 °C. The content of flavonoids from Ginkgo biloba L. was more than 90%, and the yield reached 78.3% under the optimal preparation process. [ Conclusion ] High-purily flavonoids from Ginkgo biloba L. were obtained, which provided an effective method for the preparation of highly purified Ginkgo biloba L. flavonoids.%[目的]制备高纯度的银杏黄酮,探索一条规模化制备高纯度银杏总黄酮的工艺路线.[方法]用固相填料为ODS的色谱柱纯化银杏黄酮,考察梯度洗脱、浓缩温度、干燥温度对银杏黄酮含量的影响.[结果]甲醇∶0.5%磷酸=5∶5和7∶3(V∶V)的馏分为目标馏分,最佳浓缩温度和干燥温度为45 ℃,在最佳条件下,银杏黄酮质量百分含量≥90%,收率为78.3%.[结论]该试验获得了高纯度银杏黄酮,为高纯度的银杏总黄酮制备提供了一种高效的方法.

  17. Design of a safe facility for the metalorganic chemical vapor deposition of high-purity GaAs and AlGaAs

    Science.gov (United States)

    Messham, R. L.; Tucker, W. K.

    1986-09-01

    A metalorganic chemical vapor deposition (MOCVD) facility designed to safely handle highly toxic and pyrophoric growth materials is described. The system concept is based on remote operation, passive flow restriction, and forced air dilution to maintain safe gas concentrations under normal running and catastrophic system failure conditions. MOCVD is a key materials technology for advanced high-frequency optical and microwave devices. At this time, the use of highly toxic arsine as an arsenic source is dictated by critical device purity, reproducibility, and doping control requirements. The handling and use of this gas is a primary feature in the design of any safe facility for MOCVD growth of high-quality GaAs/AlGaAs. After a critical review of presently available effluent treatment techniques, it was concluded that a combination of flow restriction and dilution presented the most reliable treatment. Measured flow rates through orifices from 0.002 to 0.005 inch in diameter were compared to calculated values. A 0.002 inch orifice located in the cylinder valve or CGA fitting, combined with a cylinder of pure liquid arsine (205 psi), limits the maximum gas flow to ≪1 lpm. Such a flow can then be vented through a dedicated exhaust system where an additional forced injection of diluting air reduces the gas concentration to acceptable levels. In the final Westinghouse R&D Center design, the use of low-pressure pure arsine, flow restriction, and stack air injection has reduced the maximum stack exist gas concentration to below 25% of the IDLH level for arsine under total and catastrophic MOCVD facility equipment failure conditions. The elimination of potential problems with purging behind such orifices using carefully designed purging procedures and a microprocessor-controlled purging system are described. The IDLH level is defined by the OSHA and NIOSH standards completion program and represents the maximum level from which one could escape within 30 min without any

  18. Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

    International Nuclear Information System (INIS)

    Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ∼0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

  19. Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

    Science.gov (United States)

    Yater, J. E.; Shaw, J. L.; Pate, B. B.; Feygelson, T. I.

    2016-02-01

    Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ˜0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

  20. Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor.

    Science.gov (United States)

    Kelp, G; Tätte, T; Pikker, S; Mändar, H; Rozhin, A G; Rauwel, P; Vanetsev, A S; Gerst, A; Merisalu, M; Mäeorg, U; Natali, M; Persson, I; Kessler, V G

    2016-04-01

    Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped. PMID:26960813

  1. Quantitative determination of trace metals in high-purity silicon carbide powder by laser ablation inductively coupled plasma mass spectrometry without binders

    International Nuclear Information System (INIS)

    We have developed a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) method to directly determine the concentrations of trace metals in high-purity powdery silicon carbide (SiC) samples. The sample preparation procedure is simple and rapid. The sample was formed into pellets using no binders and heated at 1000 °C for 2 h. The operation parameters for LA and ICP-MS were optimized to achieve a table signal intensity and high sensitivity. National Institute of Standards and Technology Standard Reference Materials glasses were chosen as calibration standards, with 29Si chosen as the internal standard. The relative sensitivity factor obtained from the glass matrix was used to calculate the concentrations of analytes in the SiC ceramic samples. The regression correlation coefficients of the calibration curves for elements with internal standard correction ranged from 0.9981 to 0.9999, which are better than those obtained with an external standard correction method only. The relative standard deviation of the measured trace element concentrations was less than 5%. The limits of detection were 0.02, 0.08, 0.04, 0.005, 0.01, 0.02, 0.004, 0.07, and 0.006 mg kg−1 for B, Ti, Cr, Mn, Fe, Ni, Co, Cu, and Sr, respectively. The method was applied to analyze SiC samples with two different particle sizes. The analysis showed good agreement with the results of inductively coupled plasma optical emission spectrometry. The reliability of the proposed method was confirmed by determining the contents of B, Ti, Cr, Mn, Fe, Ni, and Cu in BAM-S003. - Highlights: • Powdery SiC was converted into stable targets without any binders. • Stable signals for trace elements were obtained with RSDs less than 5%. • This method was successfully used to analyze silicon carbide samples with μm and nm particle sizes. • The limits of detection were much better than those obtained for INAA, SIS-ET-AAS, ICP-MS-decomposition, and other methods

  2. High-purity magnesium interference screws promote fibrocartilaginous entheses regeneration in the anterior cruciate ligament reconstruction rabbit model via accumulation of BMP-2 and VEGF.

    Science.gov (United States)

    Cheng, Pengfei; Han, Pei; Zhao, Changli; Zhang, Shaoxiang; Wu, Hongliu; Ni, Jiahua; Hou, Peng; Zhang, Yuanzhuang; Liu, Jingyi; Xu, Haidong; Liu, Shen; Zhang, Xiaonong; Zheng, Yufeng; Chai, Yimin

    2016-03-01

    Interference screw in the fixation of autologous tendon graft to the bone tunnel is widely accepted for the reconstruction of anterior cruciate ligament (ACL), but the regeneration of fibrocartilaginous entheses could hardly be achieved with the traditional interference screw. In the present work, biodegradable high-purity magnesium (HP Mg) showed good cytocompatibility and promoted the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF), fibrocartilage markers (Aggrecan, COL2A1 and SOX-9), and glycosaminoglycan (GAG) production in vitro. The HP Mg screw was applied to fix the semitendinosus autograft to the femoral tunnel in a rabbit model of ACL reconstruction with titanium (Ti) screw as the control. The femur-tendon graft-tibia complex was retrieved at 3, 6, 9 and 12 weeks. Gross observation and range of motion (ROM) of the animal model reached normal levels at 12 weeks. No sign of host reaction was found in the X-ray scanning. The HP Mg group was comparable to the Ti group with respect to biomechanical properties of the reconstructed ACL, and the ultimate load to failure and stiffness increased 12 weeks after surgery. In the histological analysis, the HP Mg group formed distinct fibrocartilage transition zones at the tendon-bone interface 12 weeks after surgery, whereas a disorganized fibrocartilage layer was found in the Ti group. In the immunohistochemical analysis, highly positive staining of BMP-2, VEGF and the specific receptor for BMP-2 (BMPR1A) was shown at the tendon-bone interface of the HP Mg group compared with the Ti group. Furthermore, the HP Mg group had significantly higher expression of BMP-2 and VEGF than the Ti group in the early phase of tendon-bone healing, followed by enhanced expression of fibrocartilage markers and GAG production. Therefore we proposed that the stimulation of BMP-2 and VEGF by Mg ions was responsible for the fibrochondrogenesis of Mg materials. HP Mg was promising as a

  3. Simultaneous Determination of Trace Rare Earth Elements and Other Elements in High Purity Terbium Oxide (Tb4O7) by ICP-AES After HPLC Separation Using P507 Resin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article describes a new method for the simultaneous determination of trace rare earth elements (REEs) and non rare earth elements (NREEs) in high purity terbium oxide by ICP-AES after HPLC separation using P507 resin. The chromatographic separation of the analytes from the matrix using dilute nitric acid as mobile phase was studied. The experimental results showed that a favorable separation of trace metals (Cu and Gd) from the matrix (Tb) can easily be achieved by elution with dilute nitric acid within 25 min. The proposed method was applied to the determination of trace metals (Ca, Cu, Mg, Mn, Ni, Si, La, Ce, Pr, Nd, Sm, Eu and Gd) in high purity terbium oxide. The detection limits (DLs) for the analytes ranged from 0.4-4.0 μg\\5g-1, and the recoveries are from 78%-105%.

  4. Use of electrodeposition for sample preparation and rejection rate prediction for assay of electroformed ultra high purity copper for 232Th and 238U prior to inductively coupled plasma mass spectrometry (ICP/MS)

    International Nuclear Information System (INIS)

    The search for neutrinoless double beta decay in 76Ge has driven the need for ultra-low background Ge detectors shielded by electroformed copper of ultra-high radiopurity (232Th and 238U into the plating bath simulates low purity copper and allows for the calculation of the electrochemical rejection rate of thorium and uranium in the electroplating system. This rejection value will help to model plating bath chemistry. (author)

  5. 论降膜结晶法在高纯硫酸制备中的重要性%On the Importance of Falling Film Crystallization Method for Preparing High Purity Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    邵勇; 陈林; 朱龙

    2016-01-01

    目前,关于高纯硫酸的制造工艺还不够先进,其中成本浪费很大,且不易操作,需要进一步优化。降膜结晶法应用于高纯硫酸制备,可减少其制备过程中的原料成本浪费,对于绿色环保经济发展也产生了积极作用。采用减压蒸馏、降膜结晶工艺对工业硫酸进行净化提纯,可以制备出达到 BV-Ⅲ级的高纯硫酸。降膜结晶法在高纯硫酸制备中有着重要的意义。%At present,about the manufacturing process of high purity sulfuric acid is still not advanced enough,the cost of which waste large and difficult to operate,need to be further optimized.Falling film crystallization method used in the preparation of high purity sulfuric acid,which can reduce the cost of raw materials preparation process waste for green economic development also had a positive benefit.By vacuum distillation,falling film crystallization process for purification of industrial sulfuric acid purification,can be prepared to achieve BV-Ⅲ grade high purity sulfuric acid.Falling film crystallization method has an important significance in the preparation of high purity sulfuric acid.

  6. Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

    Energy Technology Data Exchange (ETDEWEB)

    Chernyshov, Alexander S. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac magnetic susceptibility, and heat capacity of high purity single crystals of dysprosium have been investigated over broad temperature and magnetic field intervals with the magnetic field vector parallel to either the a- or c-axes of the crystal. Notable differences in the behavior of the physical properties when compared to Dy samples studied in the past have been observed between 110 K and 125 K, and between 178 K and ~210 K. A plausible mechanism based on the formation of antiferromagnetic clusters in the impure Dy has been suggested in order to explain the reduction of the magnetocaloric effect in the vicinity of the Neel point. Experimental and theoretical investigations of the influence of commensurability effects on the magnetic phase diagram and the value of the magnetocaloric effect have been conducted. The presence of newly found anomalies in the physical properties has been considered as evidence of previously unreported states of Dy. The refined magnetic phase diagram of dysprosium with the magnetic field vector parallel to the a-axis of a crystal has been constructed and discussed. The magnetic and crystallographic properties of Gd5SbxGe4-x pseudo-binary system were studied by x-ray diffraction (at room temperature), heat capacity, ac-magnetic susceptibility, and magnetization in the temperature interval 5-320 K in magnetic fields up to 100 kOe. The magnetic properties of three composition (x = 0.5, 1,2) were examined in detail. The

  7. Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor

    Science.gov (United States)

    Kelp, G.; Tätte, T.; Pikker, S.; Mändar, H.; Rozhin, A. G.; Rauwel, P.; Vanetsev, A. S.; Gerst, A.; Merisalu, M.; Mäeorg, U.; Natali, M.; Persson, I.; Kessler, V. G.

    2016-03-01

    Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped.Tin oxide is considered to be one of the

  8. Analysis of the Purity of Cetrimide by Titrations

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Rasmussen, Claus/Dallerup; Nielsen, Hans/Boye

    2006-01-01

    The purity of cetrimide, trimethyl tetradecyl ammonium bromide (TTAB), that is an important preservative of many cosmetic and pharmaceutical products, was determined by three independent methods of titration. Traditionally, cetrimide was analysed by an assay method of the European Pharmacopoeia (Ph....... Eur.), which showed consistently a low purity of cetrimide with large standard deviations associated, however. A systematic 3% bias of the Ph. Eur. assay method was identified by comparing the result with results of two alternative methods of titration that exhibited high precision and high accuracy....... Titration by perchloric acid showed a 99.69 ± 0.05 % purity of cetrimide and titration by silver nitrate showed a 99.85% ± 0.05 % purity while the traditional assay method predicted a purity of only 97.1 ± 0.4. It was found that the discrepancy could be identified as differences in selectivity during...

  9. mu. /sup +/ diffusion and trapping in high purity and oxygen-doped Nb. [Temperature dependence, 10 to 120/sup 0/K, impurity-associated traps

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.A.; Heffner, R.H.; Leon, M.; Parkin, D.M.; Schillaci, M.E.; Gauster, W.B.; Fiory, A.T.; Kossler, W.J.; Birnbaum, H.K.; Denison, A.B.; Cooke, D.W.

    1978-01-01

    Data are presented for the temperature dependence of the muon depolarization rate between 10 and 120 K for three samples of niobium of varying purity. Two samples, each containing approximately 200 ppM substitutional Ta and interstitial concentrations of 10 ppM and 560 ppM (mostly O), respectively, were studied. A third sample containing only 3 ppM Ta and an estimated 10 ppM total interstitial impurities was also measured. The results indicate that even at the lowest temperatures studied the depolarization of the muon is dominated by traps associated with impurities. 9 references.

  10. A New Route for High-Purity Organic Materials: High-Pressure-Ramp-Induced Ultrafast Polymerization of 2-(Hydroxyethyl)Methacrylate

    Science.gov (United States)

    Evlyukhin, E.; Museur, L.; Traore, M.; Perruchot, C.; Zerr, A.; Kanaev, A.

    2015-12-01

    The synthesis of highly biocompatible polymers is important for modern biotechnologies and medicine. Here, we report a unique process based on a two-step high-pressure ramp (HPR) for the ultrafast and efficient bulk polymerization of 2-(hydroxyethyl)methacrylate (HEMA) at room temperature without photo- and thermal activation or addition of initiator. The HEMA monomers are first activated during the compression step but their reactivity is hindered by the dense glass-like environment. The rapid polymerization occurs in only the second step upon decompression to the liquid state. The conversion yield was found to exceed 90% in the recovered samples. The gel permeation chromatography evidences the overriding role of HEMA2•• biradicals in the polymerization mechanism. The HPR process extends the application field of HP-induced polymerization, beyond the family of crystallized monomers considered up today. It is also an appealing alternative to typical photo- or thermal activation, allowing the efficient synthesis of highly pure organic materials.

  11. On the interaction mechanisms between atmospheric sources of hydrogen and Al-Si coated or bare high strength steels during the hot stamping process

    OpenAIRE

    Mandy, Mélodie; Georges, Cédric; Drillet, Pascal; Sturel, Thierry; Jacques, Pascal; SF2M - workshop "Mapping the future of materials science"

    2015-01-01

    The economic and ecological challenges of the automotive industry coupled to safety considerations involve lightweight design based on the development of new ultra high strength materials. The hot stamping process of Al-Si coated steels ensures these strength levels and, moreover, allows an easy forming of the material without the necessity of a controlled atmosphere. At high temperatures, the coating is hydrogen-permeable, while at low temperatures (below 120°C), it becomes tight to hydrogen...

  12. Matrix methods for bare resonator eigenvalue analysis.

    Science.gov (United States)

    Latham, W P; Dente, G C

    1980-05-15

    Bare resonator eigenvalues have traditionally been calculated using Fox and Li iterative techniques or the Prony method presented by Siegman and Miller. A theoretical framework for bare resonator eigenvalue analysis is presented. Several new methods are given and compared with the Prony method.

  13. 痕量杂质离子对高纯水电导率的影响%Influence of Trace Ionic Contaminants on Conductivity of High-Purity Water

    Institute of Scientific and Technical Information of China (English)

    慕晓炜; 郑敏聪; 李建华

    2013-01-01

    该文介绍并分析了痕量杂质离子(Na+、NH4+Cl-)对高纯水电导率的影响,结果表明温度为25C且高纯水中仅存在0~0.88 μg/L的Na+时(除了水电离的H+和OH-),水样的电导率会低于0.054 8 μS/cm的理论值;当Na+含量为0.44 μg/L时,电导率达到最小值0.054 5μS/cm.可见高纯水中存在痕量Na+对电导率的影响甚微.如果高纯水中只存在有痕量NH4+或Cl-时(除了水电离的H+和OH-)并不会出现水样电导率低于理论值的情况.%Influence of trace ionic contaminants, such as Na+, NH4 and Cl-, on high-purity water conductivity was introduced in this paper. It is shown that high-purity water only containing less than 0.88 μg/L Na+ (except H+ and OH- ionized by water) can make sample conductivity be slightly below the theoretical value. The minimum value is 0.054 5 μS/cm when water contains 0.44 μg/L Na+. It can be seen trace Na+ in pure water has little effect on the conductivity. But if high-purity water only contain ammonium or chloride (except the H+ and OH- ionized by water), sample conductivity will not be below the theoretical value.

  14. PREPARATION OF EPA AND DHA ESTERS WITH HIGH PURITY BY SUPERCRITICAL CO2 EXTRACTION AND RECTIFICATION%超临界CO2萃取精馏制取高纯度EPA乙酯和DHA乙酯

    Institute of Scientific and Technical Information of China (English)

    邱榕; 范维澄; 陈钧

    2001-01-01

    Fish oil ethyl esters complexed with aqueous silver nitrate solution were extracted and rectified by supercritical CO2 to obtain DHA ester and EPA ester with high purity. The effects of some independent variables,such as extraction pressure, temperature gradient of rectifying column and programmed pressure,on rectification were investigated.The results showed that programmed pressure is suitable for purification of EPA and DHA esters. Increase of column temperature gradient from bottom to top is one of the key elements in rectification. Furthermore, higher temperature gradient leads to better separation effect.

  15. Determination of the type of stacking faults in single-crystal high-purity diamond with a low dislocation density of <50 cm-2 by synchrotron X-ray topography

    Science.gov (United States)

    Masuya, Satoshi; Hanada, Kenji; Uematsu, Takumi; Moribayashi, Tomoya; Sumiya, Hitoshi; Kasu, Makoto

    2016-04-01

    The properties of stacking faults in a single-crystal high-purity diamond with a very low dislocation density of on the basis of the f · g extinction criteria. Furthermore, we have found that the partial dislocations are of the Shockley type on the basis of the b · g extinction criteria. Consequently, we concluded that the stacking faults are of the Shockley type and formed because of the decomposition of dislocations with \\textbf{b} = a/2 into dislocations with \\textbf{b} = a/6 and a/6 .

  16. The Liquid Argon Purity Demonstrator

    CERN Document Server

    Adamowski, M; Dvorak, E; Hahn, A; Jaskierny, W; Johnson, C; Jostlein, H; Kendziora, C; Lockwitz, S; Pahlka, B; Plunkett, R; Pordes, S; Rebel, B; Schmitt, R; Stancari, M; Tope, T; Voirin, E; Yang, T

    2014-01-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  17. The Liquid Argon Purity Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

    2014-07-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  18. Purity homophily in social networks.

    Science.gov (United States)

    Dehghani, Morteza; Johnson, Kate; Hoover, Joe; Sagi, Eyal; Garten, Justin; Parmar, Niki Jitendra; Vaisey, Stephen; Iliev, Rumen; Graham, Jesse

    2016-03-01

    Does sharing moral values encourage people to connect and form communities? The importance of moral homophily (love of same) has been recognized by social scientists, but the types of moral similarities that drive this phenomenon are still unknown. Using both large-scale, observational social-media analyses and behavioral lab experiments, the authors investigated which types of moral similarities influence tie formations. Analysis of a corpus of over 700,000 tweets revealed that the distance between 2 people in a social-network can be predicted based on differences in the moral purity content-but not other moral content-of their messages. The authors replicated this finding by experimentally manipulating perceived moral difference (Study 2) and similarity (Study 3) in the lab and demonstrating that purity differences play a significant role in social distancing. These results indicate that social network processes reflect moral selection, and both online and offline differences in moral purity concerns are particularly predictive of social distance. This research is an attempt to study morality indirectly using an observational big-data study complemented with 2 confirmatory behavioral experiments carried out using traditional social-psychology methodology. PMID:26726910

  19. Simultaneous determination of sub μg·g-1 levels of nine impurities in high purity iron by horizontal cation exchange resin mini-column and ICP-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Inductively coupled plasma-atomic emission spectrometry (ICP-AES) has been applied to the simultaneous determination of trace impurities in high purity iron after simultaneous separation. Sub μg·g-1 levels of Ca, Cd, Co, Cu, Mg, Mn, Ni, Pb and Zn in high purity iron which had been dissolved in hydrofluoric acid and hydrogen peroxide were separated from the iron matrix using a horizontal cation exchange resin mini-column. Flow rates and flow directions of solutions through the mini-column were controlled by a peristaltic pump. Adsorbed elements on the resin mini-column were rapidly eluted using a reverse flow of the eluant against the flow for the adsorption. The eluted elements were determined by ICP-AES using an internal standard method and good results were obtained. A 100-fold enrichment of analytes was obtained with this preconcentration system using 1 g of the sample in comparison with an ordinary sample solution in which 0.5 g of the sample was dissolved in 100 cm3 without separation. (author)

  20. 采用ICP-AES测定高纯氢氧化钠中Ca、Al、Si的含量%Using ICP-AES to determine the concentration of Ca, Al and Si in high-purity sodium hydroxide

    Institute of Scientific and Technical Information of China (English)

    丁珺

    2012-01-01

    介绍了等离子体原子发射光谱,采用标准加入法测定高纯氢氧化钠中痕量Ca、Al、Si含量的方法,该方法的准确度和精密度都符合定量要求。目前,该方法已应用于高纯氢氧化钠中杂质氧化钙、氧化铝、氧化硅含量的测定,且具有操作简便、省时、省材和高灵敏度等特点,适用于批量样品的测定。%This report introduces a novel method to determine the concentration of trace impurities in high- purity sodium hydroxide. The method uses ICP-AES combined with standard addition, thus its accuracy and precision fits the requirement of quantitative measurement. This method has been successfully applied to determine the concentration of calcium oxide (CaO), aluminum oxide (A1203) and silicon dioxide (SiO2) in high-purity sodium hydroxide. The method is not only convenient, fast but also very sensitive, therefore is suitable for batch analysis.

  1. Stress corrosion cracking in high-purity water of 3-31/2% NiCrMoV low-alloy steels for steam turbine disks and rotors. Pt. 1

    International Nuclear Information System (INIS)

    In recent years intergranular stress corrosion cracking has occurred world-wide in the shrink-fitted discs of low pressure turbine rotors made of low alloy steels. Only in a few cases steam impurities such as NaOH, Na2CO3, Na2SO4, H2S or NaCl, which initiate SCC, could be found. To clarify the SCC-behaviour experiments on turbine disc steels with different chemical compositions and yield strength were performed in high purity water. The results show, that chemical composition has no effect on the crack initiation. Under high purity water conditions no crack initiation due to stress corrosion cracking is observed on the steel with a yield strength of 850 N/mm2. On the steel with a yield strength of 1250 N/mm2 which is not used in service, crack initiation occurs in pure water. But if sharp cracks already exist, crack propagation occurs in both cases. The investigations showed, that stress corrosion cracking of turbine discs can be prevented by a good water chemistry with a cation conductivity less than 0.2 μS/cm (μmho/cm). (orig.)

  2. Challenges of the management of severe hemophilia A with inhibitors: two case reports emphasizing the potential interest of a high-purity human Factor VIII/von Willebrand factor concentrate and individually tailored prophylaxis guided by thrombin-generation test.

    Science.gov (United States)

    Mathieu, Sophie; Crampe, Carine; Dargaud, Yesim; Lavigne-Lissalde, Géraldine; Escuriola-Ettingshausen, Carmen; Tardy, Brigitte; Meley, Roland; Thouvenin, Sandrine; Stephan, Jean L; Berger, Claire

    2015-12-01

    Severe hemophilia A is an X-linked bleeding disorder. Immune tolerance induction (ITI) is the best strategy of treatment when patients develop inhibitors. The objective is to illustrate the benefit of a high-purity human factor VIII/von Willebrand factor (VWF) concentrate (Octanate) in the management of ITI. We also wanted to raise the potential interest of laboratory assays such as thrombin-generation test (TGT) and epitope mapping. Two patients were treated during ITI, first with a recombinant FVIII and then with plasma-derived factor VIII without success, and, finally, with Octanate. Bypassing agents were used based on the results of TGT. Epitope mapping was performed during ITI therapy. These observations suggest the potential contribution of Octanate in the management of ITI in difficult cases. The use of bypassing agents can be necessary in prophylaxis or to treat bleedings, and may be guided by TGT results. Epitope mapping is used to describe the inhibitor. This article shows a decrease of the inhibitor directed against the C2 domain after initiation of Octanate. A high-purity human factor VIII/von Willebrand factor concentrate (Octanate) may be a valuable therapeutical option for ITI therapy. TGT and epitope mapping could be of help in the management of ITI. PMID:26517064

  3. Challenges of the management of severe hemophilia A with inhibitors: two case reports emphasizing the potential interest of a high-purity human Factor VIII/von Willebrand factor concentrate and individually tailored prophylaxis guided by thrombin-generation test.

    Science.gov (United States)

    Mathieu, Sophie; Crampe, Carine; Dargaud, Yesim; Lavigne-Lissalde, Géraldine; Escuriola-Ettingshausen, Carmen; Tardy, Brigitte; Meley, Roland; Thouvenin, Sandrine; Stephan, Jean L; Berger, Claire

    2015-12-01

    Severe hemophilia A is an X-linked bleeding disorder. Immune tolerance induction (ITI) is the best strategy of treatment when patients develop inhibitors. The objective is to illustrate the benefit of a high-purity human factor VIII/von Willebrand factor (VWF) concentrate (Octanate) in the management of ITI. We also wanted to raise the potential interest of laboratory assays such as thrombin-generation test (TGT) and epitope mapping. Two patients were treated during ITI, first with a recombinant FVIII and then with plasma-derived factor VIII without success, and, finally, with Octanate. Bypassing agents were used based on the results of TGT. Epitope mapping was performed during ITI therapy. These observations suggest the potential contribution of Octanate in the management of ITI in difficult cases. The use of bypassing agents can be necessary in prophylaxis or to treat bleedings, and may be guided by TGT results. Epitope mapping is used to describe the inhibitor. This article shows a decrease of the inhibitor directed against the C2 domain after initiation of Octanate. A high-purity human factor VIII/von Willebrand factor concentrate (Octanate) may be a valuable therapeutical option for ITI therapy. TGT and epitope mapping could be of help in the management of ITI.

  4. 尿素柱层析结合重结晶制备高纯度茄尼醇%Preparation of High-purity Solanesol by Urea Column Chromatography Combining with Recrystallization

    Institute of Scientific and Technical Information of China (English)

    韩蕊蕊; 吕纯洁; 邓天昇; 刘旭光; 侯相林

    2012-01-01

    为制备高纯度的茄尼醇,进行了尿素柱层析结合重结晶分离茄尼醇试验,考察了尿素柱层析固定相尿素与硅胶的比例、洗脱溶剂、上样量对茄尼醇纯度和收率的影响.结果表明:尿素柱层析固定相尿素与硅胶质量比1∶1,洗脱剂石油醚与乙酸乙酯体积比60∶1,上样量0.4 g,茄尼醇的纯度和收率分别为74.8%和89.8%.再经过甲醇、乙腈各结晶一次,茄尼醇的纯度达96.7%,总收率0.1248%.该方法可以用于浸膏中茄尼醇的精制.%To obtain high-purity solanesol, an experiment on the refinement of solanesol by urea column chromatography combining with recrystallization was conducted. The influences of ratio of urea to silica gel in stationary phase, elution solvent and the sample loading in urea column chromatography on the purity and yield of solanesol were investigated. The results showed that when the mass ratio of urea to silica gel in stationary phase was 1:1 (w/w), the proportion of petroleum ether to ethyl acetate in elution solvent was 60:1 (v/v), the sample loading was 0.4 g, the purity and yield of solanesol reached 74.8% and 89.8% , respectively. The resultant solanesol was recrystalized in methanol and acetonitrile sequentially, and a white crystalline solanesol was obtained with purity of 96.7% and yield of 0.1248%.

  5. 高纯菜籽蛋白的制备及其相关性质研究%Study on preparation of high-purity rapeseed protein and its properties

    Institute of Scientific and Technical Information of China (English)

    周俊; 潘丽军; 韩智宏

    2012-01-01

    Protein was extracted from coldpressed rapeseed meal which was detoxicated firstly,then the extract was ultrafiltered to obtain high-purity rapeseed protein,chemical components,amino acid and function of proteins were also studied.Extraction rate of protein from rapeseed meal after detoxication was 67.97%,rapeseed protein of different purity from 70% to 90% could be prepared by ultrafiltration.Phytic acid,glucosinolate were not detected in proteins,and content of polyphenol was decreased obviously with rise of protein purity.Sulphur-containing amino acid(Methionine+Cysteine) was the first limiting amino acid.Chemical scores of the other essential amino acids were higher than FAO/WHO standard,but most were inferior to standard of whole egg protein.Capacities of water-holding,fat-absorbing,emulsion,emulsion stability,foaming and foam stability correlated positively with purity of rapeseed protein.%对脱毒后的冷榨菜籽粕进行蛋白提取,超滤纯化提取液获得高纯度的蛋白成品,并研究分析了蛋白的成分、氨基酸及其功能特性。脱毒后菜籽粕中蛋白提取率为67.97%,超滤后蛋白纯度可达70%~90%。成品蛋白中植酸与硫苷未检出,多酚含量随蛋白纯度增加而显著下降,甲硫氨酸+半胱氨酸是第一限制性氨基酸,其余必需氨基酸化学评分均高于FAO/WHO标准,却大多低于全蛋蛋白标准。菜籽蛋白的持水性、吸油性、乳化性及乳化稳定性、起泡性及起泡稳定性均与蛋白纯度呈正相关。

  6. 粉石英制备高纯球形纳米SiO2%Preparation of High-purity Spherical Nano-SiO2 from Powder Quartz

    Institute of Scientific and Technical Information of China (English)

    旦辉; 丁艺; 林金辉

    2012-01-01

    High-purity spherical nano-SiO2 powder was prepared from low-price high-quality powder quartz by sol-gel method and the way of simultaneous addition of hydrochloric acid and sodium silicate solutions. The effects of concentration and purity of sodium silicate, the dosage of ammonia, pH, surfactant and dispersing agent on the performance of nano-Si02 powder were investigated. The purity of SiO2 powder was analyzed and the nano-Si02 was also characterized by XRF,XRD and SEM. The chemical composition of the nano-SiO2 powder was;99.97wt%SiO2 ,9× 10-6Al3+ ,no more than1.04×10-6 Fe3+ ,no more than 3. 5×10-6 Na+ ,no more than 1 ×10-6 Cl- and no more than 1× 10-6SO42-. The results of the study show that the nano-SiO2 which was prepared in this study was highly pure spherical, highly dispersed and uniform in particle size. The performance of nano-SiO2 can satisfy the requirement of functional filler of electronic packaging materials. This paper was focused on the influence of the purity of raw material on the purity of nanometer SiO2,the mechanism and method of aggregation reduction.%以价格低廉天然优质粉石英矿物为基本原料,采用改进溶胶-凝胶技术,盐酸和硅酸钠溶液共滴加的方式,制备高纯球形纳米SiO2粉体材料.研究了体系中硅酸钠浓度及纯度、pH值、表面活性剂及分散剂等因素对其性能的影响.制备出的高纯纳米SiO2粉体中SiO299.97%、Al3+ 9×10-6、Fe3+ 1.04 9×10-6、Na+≤3.59×10-6、Cl-≤19×10-6,平均粒径在50~80 nm.研究结果表明:制备的SiO2粉体为高纯、球形、分散度高且粒度均匀,能达到电子封装材料功能填料用高纯球形纳米二氧化硅性能指标要求.本文重点探讨原材料对其纯度的影响,团聚机理及解决团聚的措施.该方法具有成本低及易于工业化的特点.

  7. Síntese e caracterização de precursores de cério de alta pureza Synthesis and characterization of high purity cerium precursors

    Directory of Open Access Journals (Sweden)

    C. A. S. Queiroz

    2001-03-01

    Full Text Available Neste trabalho são destacadas as técnicas de separação e de purificação de terras raras por precipitação fracionada e troca iônica, além das técnicas usualmente utilizadas no controle analítico destes materiais. A aplicação destas técnicas é mostrada neste trabalho para a obtenção de óxido ou nitrato de cério com pureza > 99%. O principal objetivo é a obtenção de precursores à base de cério para o processamento de cerâmicas de zircônia-céria ou céria contendo terras raras. A disponibilidade de cloretos mistos, matéria-prima para a preparação de terras raras individuais, e o conhecimento das técnicas de separação, purificação e controle analítico de terras raras no IPEN, permite sua obtenção local para uso em pesquisa e desenvolvimento.In this work techniques of fractioned precipitation and ion exchange for separating and purifying rare earth elements are outlined. Other techniques usually utilized in the analytical control of these elements are also briefly discussed. The application of these techniques for the preparation of cerium nitrate or cerium oxide of > 99% purity are demonstrated. The main purpose is to obtain cerium precursors for the processing of zirconia-ceria or ceria-rare earth ceramic materials. The raw material availability in the form of mixed chlorides, and the knowledge of these techniques at IPEN allows for obtaining these precursors in the local market for research and development purposes.

  8. UV Active Diluent High Purity Tripropylene Glycol Diacrylate(TPGDA) and Its UV Coatings%UV活性稀释剂高纯二缩三丙二醇二丙烯酸酯及其UV涂料

    Institute of Scientific and Technical Information of China (English)

    胡剑飞; 付鹏志; 马怀详; 桑卫东

    2012-01-01

    Intermediate was prepared via the ring-opening polymerization in the presence of catalyst and 1,2-propylene glycol and propylene oxide used as raw materials, the intermediate as separated by a special rectifying process, the tripropylene glycol of over 98% purity was obtained. Finally, high purity TPGDA was synthesized by esterifieation with acrylic acid. The ester distribution of tripropylene glycol diacrylate before and after purifying the tripropylene glycol and performance difference in their application of UV coatings was systematic analyzed.%1,2-丙二醇、环氧丙烷在催化剂的作用下进行开环聚合反应得中间体,再对中间体采用特殊精馏方式进行组分分离,得到纯度达98%以上的二缩三丙二醇,然后经丙烯酸酯化得高纯TPGDA。系统分析二缩三丙二醇提纯前及提纯后所合成的光固化单体二缩三丙二醇二丙烯酸酯(TPGDA)的酯分布及其在UV涂料应用中的性能差异。

  9. Ways for accurate analysis of high purity materials using the glow discharge mass spectrometry (GD-MS); Wege zur genauen Charakterisierung hochreiner Materialien mit der Glimmentladungs-Massenspektrometrie (GD-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Gusarova, Tamara

    2010-04-14

    The main aim of this work consists in the investigation, development and application of improved possibilities of accurate analysis of high purity materials using the solid sample technique of Glow Discharge Mass Spectrometry (GD-MS), as well as in the sensitivity enhancement of GD Optical Emission Spectrometry (GD-OES) by implicating the hollow cathode effect. The emphasis of the PhD thesis consists in the accurate quantification for GD-MS. As appropriate certified reference materials (CRMs) for calibration are lacking in most cases an accurate quantification especially for trace elements mass fractions at {mu}g kg{sup -1} level can often not be achieved. To overcome this problem and to expand the possibilities of modern GD-MS hereby, synthetic standards were applied for calibration of both high resolution GD-MS instruments ''VG 9000'' and ''Element GD''. The standards were prepared by doping of matrix powder with trace element standard solutions followed by drying and pressing the doped powder to compact pellets. With the quantification approach worked out and described here accurate analysis results with small uncertainties can be achieved for most elements of periodic table in almost every matrix composition. Furthermore direct traceability of the analytical results to the International System of Units (SI) is provided ensuring their higher metrological quality. Numerous additional systematic investigations concerning the preparation of the synthetic standards and their properties were carried out. The results of calibration of GD-MS instruments with synthetic standards for Co (Co-C), Cu, In, Fe and Zn matrices were checked by measuring CRMs. These results were also contrasted with those of other quantification approaches, as usually used in GD-MS routine. The results achieved with synthetic standards had the highest accuracy. The successful participation in the round robin test CCQM-P107 between international

  10. 氯化钡除杂制取高纯氢氧化钡%Preparation of high purity barium hydroxide by impurity - removed barium chloride

    Institute of Scientific and Technical Information of China (English)

    翁贤芬; 毛逢银; 何琳; 李莉

    2009-01-01

    Removal technology of strontium and iron from crude barium chloride raw material were studied.Optimization of process conditions of strontium and iron removal were discussed.When crude barium chloride stiring and dissolving the mixture at 60 ℃ for 40 min,impurities of stromtium and calcuim can be removed and mass fraction of strontium in the obatined solid barium chloride was below 1×10-4.Then add oxydol (H2O2) at proportion of 100 g raw materials per 8 mL H2O2,and add active carbon and small quantity of sodium hydroxide.Finally,iron could be get rid of when pH was controlled below 10.Mass fraction of iron in barium hydroxide product was less than 1×10-5 when using the iron - removed barium chaloride as raw material.Therefore,purified barium chloride by this method can be used to produce purity barium hydroxide.%研究了粗氯化钡原料中锶和铁杂质的脱除工艺,探讨了脱除锶和铁的优化工艺条件.在粗氯化钡原料中加入去离子水,液固质量比为0.25: 1,在60 ℃下搅拌溶解40 min,可除去锶和钙杂质,所得氯化钡固体中锶质量分数低于1×10-4.在氯化钡溶液中加入双氧水,每100 g原料中加入双氧水8 mL,加入活性炭和少量氢氧化钠,控制pH低于10时,可除去铁杂质,用除铁后的氯化钡制取氢氧化钡,产品中铁质量分数低于1×10-5.用除杂后的氯化钡可制得高纯氢氧化钡.

  11. Bremsstrahlung from relativistic bare heavy ions: Nuclear and electronic contributions in amorphous and crystalline materials

    DEFF Research Database (Denmark)

    Jensen, Tue Vissing; Sørensen, Allan Hvidkjær

    2013-01-01

    A charged particle emits bremsstrahlung while traversing matter. We calculate the radiation cross section for bare heavy ions penetrating amorphous materials and single crystals at highly relativistic energies. The main component originates in scattering of the virtual photons of screened target...... in a pronounced directional dependence of the energy loss of bare heavy ions at extreme relativistic energies....

  12. Study of the recrystallization mechanisms of ultra-high purity iron doped with carbon, manganese and phosphorus; Etude des mecanismes de recristallisation dans le fer de ultra-haute purete dope en carbone, manganese et phosphore

    Energy Technology Data Exchange (ETDEWEB)

    Lesne, L.

    2000-07-04

    High purity steels have the potential to improve deep drawing properties for automotive applications. Understanding the influence of the chemical composition on the recrystallization mechanisms and on texture development should help to improve their properties. We have studied the influence of 10 ppm of carbon, 1000 ppm of manganese and 120 ppm of phosphorus on the recrystallization mechanisms of ultra-high purity iron (UHP iron > 99.997%). For this purpose we used 4 materials: one undoped (UHP), one doped with C, one doped with C, Mn and one doped With C, Mn, P. In order to restrict grain coarsening in the hot strips, hot rolling was performed in the ferritic region, in one pass of 80% thickness reduction. The hot bands were then fully recrystallized but exhibited non-isotropic textures, with in particular an intense Goss [110]<001> component for the doped materials. The hot-bands were subsequently cold rolled down to a thickness of 0.8 mm corresponding to a thickness reduction of 80%, and then continuously annealed at 10 deg. C/s. The recrystallization kinetics are delayed with the addition of doping elements. In particular, the incubation time for nucleation is shifted towards higher temperatures while the recrystallization velocity increases. The textures of the fully recrystallized materials exhibit a strong Goss component prejudicial for deep drawing properties. We have established that this component can only appear if coarse grains and carbon in solid solution were simultaneously present in the material before deformation. Characterisation of the cold deformed state enabled us to evaluate the energy stored during deformation as a function of the material composition and the grain orientation: - the overall stored energy increases with the doping elements content. - the stored energy in the {gamma} fibre grains is greater than in the {alpha} fibre grains: 30 J/mol for the {gamma} fibre instead of 5 J/mol for the {alpha} fibre, in the undoped UHP iron. In the

  13. Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

    Energy Technology Data Exchange (ETDEWEB)

    Pfahler, Patrick

    2012-12-17

    Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle {Theta}{sub 13}. As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m{sup 3} of muon veto scintillator and 110 m{sup 3} of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was

  14. Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

    International Nuclear Information System (INIS)

    Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle Θ13. As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m3 of muon veto scintillator and 110 m3 of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was produced and, together

  15. Evaluation of Bare Ground on Rangelands using Unmanned Aerial Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Robert P. Breckenridge; Maxine Dakins

    2011-01-01

    Attention is currently being given to methods that assess the ecological condition of rangelands throughout the United States. There are a number of different indicators that assess ecological condition of rangelands. Bare Ground is being considered by a number of agencies and resource specialists as a lead indicator that can be evaluated over a broad area. Traditional methods of measuring bare ground rely on field technicians collecting data along a line transect or from a plot. Unmanned aerial vehicles (UAVs) provide an alternative to collecting field data, can monitor a large area in a relative short period of time, and in many cases can enhance safety and time required to collect data. In this study, both fixed wing and helicopter UAVs were used to measure bare ground in a sagebrush steppe ecosystem. The data were collected with digital imagery and read using the image analysis software SamplePoint. The approach was tested over seven different plots and compared against traditional field methods to evaluate accuracy for assessing bare ground. The field plots were located on the Idaho National Laboratory (INL) site west of Idaho Falls, Idaho in locations where there is very little disturbance by humans and the area is grazed only by wildlife. The comparison of fixed-wing and helicopter UAV technology against field estimates shows good agreement for the measurement of bare ground. This study shows that if a high degree of detail and data accuracy is desired, then a helicopter UAV may be a good platform. If the data collection objective is to assess broad-scale landscape level changes, then the collection of imagery with a fixed-wing system is probably more appropriate.

  16. On line chemical analyzers for high purity steam and water, applied to steam power plants; Analizadores quimicos en linea para agua y vapor de alta pureza, aplicados a centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Perez, Ruth [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    This article presents a general overview of the advances in the subject of on line analyzers of chemical parameters for high purity water and steam and specifies which ones are commercially available. Also are mentioned besides, the criteria nowadays applied for the selection of the sites for sample grabbing and the analysis that is necessary to perform in each point, depending on the power plant type and the treatment administered (phosphates-Ph coordinated or AVT treatment). [Espanol] El articulo presenta un panorama general de los avances que en materia de analizadores de parametros quimicos en linea para agua y vapor de alta pureza, y especifica cuales estan disponibles en forma comercial. Se citan, ademas los criterios que se aplican actualmente para seleccionar los puntos de toma de muestra y los analisis que es necesario efectuar en cada punto, dependiendo del tipo de central y del tratamiento que se le administre (fosfatos-pH coordinado o tratamiento AVT).

  17. 偏析法提纯高纯铝中降温速度对去除Si和Fe的影响%The Effect of Cooling Rate on Si and Fe Removal in High Purity Aluminum Purification by Segregation Method

    Institute of Scientific and Technical Information of China (English)

    余宇楠

    2013-01-01

    The research progress of refined aluminum and high purity aluminum is introduced; the effect of cooling rate on Si and Fe segregation in industrial pure aluminum is tested and studied,the results show that the slower the cooling rate is,the more conducive to the segregation of Si and Fe in industrial pure aluminum.%介绍了精铝及高纯铝研究进展;试验研究了降温速度对Si和Fe元素在工业纯铝中偏析的影响,结果表明,降温速度越小,越有利于杂质元素Si和Fe在工业纯铝中的偏析.

  18. Removal and separation of impurity ions in preparation of high-purity inorganic salts%高纯无机盐制备中杂质离子的去除与分离

    Institute of Scientific and Technical Information of China (English)

    石磊

    2012-01-01

    介绍了在制备高纯无机盐过程中,有害杂质离子——重有色金属离子(Cu、Mg、Zn、Pd、Cd等)、铁离子、砷化物的去除与分离方法:氧化-还原法、难溶金属氢氧化物沉淀法、硫化物沉淀法.%Introduced in the preparation of high purity inorganic salt process, harmful impurity ion-heavy non-ferrous metal ion (Cu,Mg,Zn,Pd,CDS,etc. ) ,iron ion,arsenide in removing and separation methods : oxidation-reduction method and difficult to thick metal hydroxide precipitation, sulfide precipitation.

  19. Measurements of gamma (γ)-emitting radionuclides with a high-purity germanium detector: the methods and reliability of our environmental assessments on the Fukushima 1 Nuclear Power Plant accident.

    Science.gov (United States)

    Mimura, Tetsuro; Mimura, Mari; Komiyama, Chiyo; Miyamoto, Masaaki; Kitamura, Akira

    2014-01-01

    The severe accident of Fukushima 1 Nuclear Power Plant due to the Tohoku Region Pacific Coast Earthquake in 11 March 2011 caused wide contamination and pollution by radionuclides in Fukushima and surrounding prefectures. In the current JPR symposium, a group of plant scientists attempted to examine the impact of the radioactive contamination on wild and cultivated plants. Measurements of gamma (γ) radiation from radionuclides in "Fukushima samples", which we called and collected from natural and agricultural areas in Fukushima prefecture were mostly done with a high-purity Ge detector in the Graduate School of Maritime Sciences, Kobe University. In this technical note, we describe the methods of sample preparation and measurements of radioactivity of the samples and discuss the reliability of our data in regards to the International Atomic Energy Agency (IAEA) Interlaboratory comparisons and proficiency test (IAEA proficiency test). PMID:24338059

  20. The relative safety and efficacy of bare-metal and drug-eluting stents in low and high-risk patient subsets. An epidemiological analysis of three sequential cohorts of consecutive all comers (n=6129)

    NARCIS (Netherlands)

    J. Daemen (Joost); P.H. van Twisk; N. Kukreja (Neville); R.T. van Domburg (Ron); H. Boersma (Eric); P.P.T. de Jaegere (Peter); P.W.J.C. Serruys (Patrick)

    2009-01-01

    textabstractAims: Sirolimus- and paclitaxel- eluting stents (SES and PES respectively) have been shown to produce a sustained reduction in restenosis and repeat revascularisations as compared to bare-metal stents (BMS) up to four years. There is still limited data about the long-term safety and effi

  1. High Temperature Mechanical Property and Microstructure Characteristic of High Purity Al-Si Filler Metal%高纯铝硅钎料的高温力学性能和显微组织特征

    Institute of Scientific and Technical Information of China (English)

    史平安; 何建军; 王军; 李盛和

    2011-01-01

    In order to improve the welding quality and decrease the defects in laser welding-brazing of beryllium. The mechanical properties of high purity Al-Si filler metal were evaluated by high-temperature tension experiment. The microstructure characteristic, component distribution and interfacial reaction of the welded joints were analyzed by SEM and EDS. The mechanism of welding crack was investigated in the process of laser welding-brazing of beryllium. The results show that the grain size of β-Si dendrite becomes finer and uniform, with the increase of cooling rate, and all of those can make the tension strength, thermal plasticity improve. High content of C, O and Ca is detected in the crack band gathering at crystal boundary. Especially, BeO exists in the micro-cracks, the brittle phase segregates and aggregates in the grain boundary, which can result in the decrease of plasticity in local area.%为了降低铍焊缝的缺陷,提高焊接接头的强度,本文针对所研制的高纯铝硅钎料,采用高温拉伸试验、SEM扫描、能谱分析等分析手段,分析研究了其高温力学性能、组织特征和钎焊接头的成分分布,探讨了焊接缺陷形成机制.结果表明,冷却速率通过改变初生α-Al相和共晶β-Si相的形态进而影响到材料的力学性能,冷却速率增加,共晶β-Si相变细,相间距减小,材料的热塑性提高.焊缝部位的SEM及能谱分析结果显示,裂纹部位的C、O、Ca等杂质元素含量偏高,尤其是BeO在晶界的偏析严重,这些脆性相在晶界处聚集,导致局部区域塑性降低.

  2. Study on dehydration of tert-butyl alcohol to high purity isobutene by reactive distillation%叔丁醇催化精馏脱水制高纯度异丁烯中试研究

    Institute of Scientific and Technical Information of China (English)

    王艳飞; 程中克; 董炳利; 周金波; 李吉春

    2013-01-01

    Pilot-scale experiment for dehydration of tert-butyl alcohol to high purity isobutene was carried out by reactive distillation using large grain ion exchange resin catalyst in a Φ100 mm × 4 100 mm reactor.Effects of operating pressure,reflux ratio,volume flow rate of tert-butyl alcohol and filling amount of catalyst on conversion of tert-butyl alcohol were studied.The results showed that the conversion of tert-butyl alcohol was 98.12% when operating pressure was 0.39 MPa,reflux ratio was 1.5,volume flow rate of tert-butyl alcohol was 4.32 L/h,and filling amount of catalyst was 6 kg.After distillation,the purity of isobutene was 99.83%.%采用大颗粒阳离子树脂催化剂,在Φ100 mm ×4 100 mm的催化精馏中试装置上对叔丁醇脱水制异丁烯进行研究,考察操作压力、回流比、叔丁醇进料量和催化剂填装量对叔丁醇转化率的影响.结果表明,在操作压力0.39 MPa、回流比1.5、叔丁醇进料量4.32 L/h、催化剂填装量6 kg的条件下,叔丁醇转化率达98.12%,经分离后可以得到纯度为99.83%的异丁烯.

  3. Bare nominals and reference to capacities

    NARCIS (Netherlands)

    Swart, Henriëtte de; Winter, Y.; Zwarts, J.

    2007-01-01

    Prefinal version. This paper concentrates on the syntax and semantics of bare nominals in Germanic and Romance languages. These languages do not normally allow nominals to occur without an article. However, some syntactic configurations, including predicative constructions, supplementives and some p

  4. A summary of volatile impurity measurements and gas generation studies on MISSTD-1, a high-purity plutonium oxide produced by low-temperature calcination of plutonium oxalate

    Energy Technology Data Exchange (ETDEWEB)

    Berg, John M. [Los Alamos National Laboratory; Narlesky, Joshua E. [Los Alamos National Laboratory; Veirs, Douglas K. [Los Alamos National Laboratory

    2012-06-08

    Plutonium dioxide of high specific surface area was subjected to long-term tests of gas generation in sealed containers. The material preparation and the storage conditions were outside the bounds of acceptable parameters defined by DOE-STD-3013-2012 in that the material was stabilized to a lower temperature than required and had higher moisture content than allowed. The data provide useful information for better defining the bounding conditions for safe storage. Net increases in internal pressure and transient increases in H{sub 2} and O{sub 2} were observed, but were well within the bounds of gas compositions previously shown to not threaten integrity of 3013 containers.

  5. Production of high optical purity l-lactic acid from waste activated sludge by supplementing carbohydrate: effect of temperature and pretreatment time.

    Science.gov (United States)

    Jian, Qiwei; Li, Xiang; Chen, Yinguang; Liu, Yanan; Pan, Yin

    2016-10-01

    It has been widely accepted that the most environmentally beneficial way to treat waste activated sludge (WAS), the byproduct of municipal wastewater treatment plant, is to recover the valuable organic acid. However, the bio-conversion of lactic acid, one of the high added-value chemical, is seldom reported from WAS fermentation. In this paper, l-lactic acid was observed dominant in the WAS fermentation liquid with carbohydrate addition at ambient temperature. Furthermore, the effect of temperature on l-lactic acid and d-lactic acid production was fully discussed: two isomers were rapidly produced and consumed up in one day at mesophilic condition; and almost optically pure l-lactic acid was generated at thermophilic condition, yet time-consuming with yield of l-lactic acid enhancing by 52.9% compared to that at ambient temperature. The study mechanism showed that mesophilic condition was optimal for both production and consumption of l-lactic acid and d-lactic acid, while consumption of l-lactic acid and production of d-lactic acid were severely inhibited at thermophilic condition. Therefore, by maintaining thermophilic for 4 h in advance and subsequently fermenting mesophilic for 34 h, the concentration of l-lactic acid with optical activity of 98.3% was improved to 16.6 ± 0.5 g COD/L at a high specific efficiency of 0.6097/d.

  6. Production of high optical purity l-lactic acid from waste activated sludge by supplementing carbohydrate: effect of temperature and pretreatment time.

    Science.gov (United States)

    Jian, Qiwei; Li, Xiang; Chen, Yinguang; Liu, Yanan; Pan, Yin

    2016-10-01

    It has been widely accepted that the most environmentally beneficial way to treat waste activated sludge (WAS), the byproduct of municipal wastewater treatment plant, is to recover the valuable organic acid. However, the bio-conversion of lactic acid, one of the high added-value chemical, is seldom reported from WAS fermentation. In this paper, l-lactic acid was observed dominant in the WAS fermentation liquid with carbohydrate addition at ambient temperature. Furthermore, the effect of temperature on l-lactic acid and d-lactic acid production was fully discussed: two isomers were rapidly produced and consumed up in one day at mesophilic condition; and almost optically pure l-lactic acid was generated at thermophilic condition, yet time-consuming with yield of l-lactic acid enhancing by 52.9% compared to that at ambient temperature. The study mechanism showed that mesophilic condition was optimal for both production and consumption of l-lactic acid and d-lactic acid, while consumption of l-lactic acid and production of d-lactic acid were severely inhibited at thermophilic condition. Therefore, by maintaining thermophilic for 4 h in advance and subsequently fermenting mesophilic for 34 h, the concentration of l-lactic acid with optical activity of 98.3% was improved to 16.6 ± 0.5 g COD/L at a high specific efficiency of 0.6097/d. PMID:26878176

  7. Preparation of High-purity Reactive Black for Digital Printing with MF/NF Separation Technology%微滤/纳滤分离工艺制备数码喷墨印花高纯活性黑

    Institute of Scientific and Technical Information of China (English)

    张浩勤; 王慧; 秦国胜; 黄满满; 张亚涛

    2013-01-01

    In this paper,the high purity liquid reactive black was prepared by using the membrane separation technology,including the microfiltration(MF) membrane for removing particulate,the Charged-mosiac membrane (CMM) for desalination in the constant-volume filtration and the nanofiltration(NF) membrane for dehydration.The solid reactive black with high purity was prepared by spray drying.The experimental results show that with the 61.5 g · L-1 raw material liquid,under the pressure of 1.0 MPa,the salts were removed after 8 hours desalination.The purity of dye could meet the requirement and the loss rate of the dye was 0.62%.The average permeation flux of the charged-mosiac membrane was 18.5 L · m-2 · h-1 during the desalination process,which illustrated that the fouling of membrane was not so serious.Under the pressure of 1.4-1.8 MPa,the reactive black concentration can achieve 250 g · L-1 by dehydration.The solid dye was prepared by the spray drying.It was analysed that the inorganic salt in the product was lower than the imported product used by the enterprise.To sum up,the product prepared in the experiment has a good application prospect.%实验以国产活性黑粗染料为原料,采用微滤膜除杂、荷电镶嵌膜恒容脱盐和纳滤膜脱水浓缩工艺制备高纯度、高浓度液体活性染料;并通过喷雾干燥制备了高纯固体活性黑.实验结果表明:针对染料含量为61.5 g/L的原料液,在操作压力1.0 MPa条件下,脱盐8h染料纯度达到要求,染料损失率为0.62%;脱盐过程中荷电镶嵌膜的平均透过通量约为18.5 L·m-2· h-1.在1.4~1.8 MPa下,可将高纯料液脱水浓缩,使活性黑浓度达到250 g/L.实验采用喷雾干燥法制备固体染料,经分析该产品的无机盐含量低于企业目前所用的进口产品,具有良好的应用前景.

  8. Purity and adulterant analysis of crack seizures in Brazil.

    Science.gov (United States)

    Fukushima, André R; Carvalho, Virginia M; Carvalho, Débora G; Diaz, Ernesto; Bustillos, Jose Oscar William Vega; Spinosa, Helenice de S; Chasin, Alice A M

    2014-10-01

    Cocaine represents a serious problem to society. Smoked cocaine is very addictive and it is frequently associated with violence and health issues. Knowledge of the purity and adulterants present in seized cocaine, as well as variations in drug characteristics are useful to identify drug source and estimate health impact. No data are available regarding smoked cocaine composition in most countries, and the smoked form is increasing in the Brazilian market. The purpose of the present study is to contribute to the current knowledge on the status of crack cocaine seized samples on the illicit market by the police of São Paulo. Thus, 404 samples obtained from street seizures conducted by the police were examined. The specimens were macroscopically characterized by color, form, odor, purity, and adulterant type, as well as smoke composition. Samples were screened for cocaine using modified Scott test and thin-layer chromatographic (TLC) technique. Analyses of purity and adulterants were performed with gas chromatography equipped with flame ionization detector (GC-FID). Additionally, smoke composition was analyzed by GC-mass spectrometry (MS), after samples burning. Samples showed different colors and forms, the majority of which is yellow (74.0%) or white (20.0%). Samples free of adulterants represented 76.3% of the total. Mean purity of the analyzed drug was 71.3%. Crack cocaine presented no correlations between macroscopic characteristics and purity. Smoke analysis showed compounds found also in the degradation of diesel and gasoline. Therefore, the drug marketed as crack cocaine in São Paulo has similar characteristics to coca paste. High purity can represent a greater risk of dependency and smoke compounds are possibly worsening drug health impact. PMID:24887446

  9. Production d'isobutène de haute pureté par décomposition du MTBE High-Purity Isobutene Production from Mtbe

    Directory of Open Access Journals (Sweden)

    Meunier P. B.

    2006-11-01

    decomposition is catalyzed by solids with an acid nature. It has mainly been examined on catalysts of the sulfonic-resin type, but solid acid catalysts have recently appeared (zeolites, silica-alumina, supported phosphoric acid, etc. . The different types of catalysts used are examined for the principal reaction and secondary reactions. The formulation of the catalyst and the nature of the active acid sites (Brönsted or Lewis have great influence on the reaction. Data from the literature mainly concern catalysts of the resin type with Brönsted acidity. Concerning catalysts of the oxide type, mention is made of Lewis acid sites catalyzing the principal reaction. The species adsorbed, the mechanisms and kinetic investigations of MTBE decomposition have mainly been examined for sulfonic resins. The most probable mechanisms (mechanism B, page 371 is the following one :(a Ether adsorption on a double center without dissociation. (b Surface reaction between adsorbed ether and a free active center, to give rise to isobutene adsorbed on a double center without dissociation and methanol adsorbed on a single center. This stage is the one that limits the process from the kinetic standpoint. (c Desorption of isobutene and methanol. The corresponding rate equation is given in Table III, and the adsorbed species are given on page . For solid acid catalysts, few data concerning the kinetics are available in the literature. A single equation (Eq. 4, page 371, which was determined experimentally on a gamma-AI2O3 catalyst modified on the surface by silica, is proposed. On a gamma-AI2O3 catalyst, the inhibiting influence of water has been shown for high contents. Secondary reactions are mainly due to the presence of Brönsted acidity. Indeed, the dimerization and trimerization of isobutene involve mechanisms that necessitate going via a carbonium-ion intermediary on Brönsted acid sites (mechanisms on pages 372 and 377. Likewise, the dehydration of methanol is enhanced by the presence of

  10. The Production of Copper Oxide and High Purity Ferric Oxide from Low-grade Copper Ores%利用低品位铜矿生产氧化铜和高纯三氧化二铁

    Institute of Scientific and Technical Information of China (English)

    石荣铭

    2001-01-01

    The technological process of producing copper oxide and copper salts from low-grade copper ores was described in this paper.By-product,ferrous sulfate,produced in the process can be used for production of high purity iron oxide red through removing impurities and roasting ferrous sulfate under condition of adding auxiliary material.The effect of ore size,acidity,removal of impurity,roasting temperature etc,on product quality was also discussed.The optimal condition for the process was proposed.%研究了低品位铜矿生产氧化铜及铜盐并利用其副产物FeSO4经除杂纯化后与辅助材料焙烧生产高纯氧化铁红的工艺路线,讨论了矿石的粒度、酸度、除杂、提纯、焙烧温度对产品质量的影响,优化出最佳工艺条件。

  11. Study of important parameters on the irradiation of 124Xe, to improve the production of 123I with high purity using the Cyclone-30 cyclotron at IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    The development of diagnosis equipment and therapy procedures in nuclear medicine depends on the availability of commercial radioisotopes. IPEN is the most important institution that provides radioisotopes for national market. In order to achieve this function, IPEN had invested in the acquisition of a 30 MeV Cyclone-30 cyclotron to produce mainly 18F, 67Ga, 201Tl and 123I. The 123I production is the aim of the present work. With the 123I routine production data obtained by proton irradiation of Xe targets with an enrichment greater than 99.8%, it was possible to identify the important parameters that have direct influence on the production yield of high purity degree 123I. Even though the methodology for the commercial production of 123I, there are an scarcity of operational parameters data for this task. In this work the evaluated parameters were: 124Xe pressure, proton beam quality, irradiation time, operational temperature of the irradiation system under irradiation, waiting time to obtain 123I, temperature of washing solution and the impact of the internal Ni coating in the target. With the obtained results it was possible to modify the operational conditions for routine production and increasing the efficiency in about 30%. (author)

  12. The effect of incremental gamma-ray doses and incremental neutron fluences upon the performance of self-biased sup 1 sup 0 B-coated high-purity epitaxial GaAs thermal neutron detectors

    CERN Document Server

    Gersch, H K; Simpson, P A

    2002-01-01

    High-purity epitaxial GaAs sup 1 sup 0 B-coated thermal neutron detectors advantageously operate at room temperature without externally applied voltage. Sample detectors were systematically irradiated at fixed grid locations near the core of a 2 MW research reactor to determine their operational neutron dose threshold. Reactor pool locations were assigned so that fast and thermal neutron fluxes to the devices were similar. Neutron fluences ranged between 10 sup 1 sup 1 and 10 sup 1 sup 4 n/cm sup 2. GaAs detectors were exposed to exponential fluences of base ten. Ten detector designs were irradiated and studied, differentiated between p-i-n diodes and Schottky barrier diodes. The irradiated sup 1 sup 0 B-coated detectors were tested for neutron detection sensitivity in a thermalized neutron beam. Little damage was observed for detectors irradiated at neutron fluences of 10 sup 1 sup 2 n/cm sup 2 and below, but signals noticeably degraded at fluences of 10 sup 1 sup 3 n/cm sup 2. Catastrophic damage was appare...

  13. Chemical analysis of high purity graphite

    International Nuclear Information System (INIS)

    The Sub-Committee on Chemical Analysis of Graphite was organized in April 1989, under the Committee on Chemical Analysis of Nuclear Fuels and Reactor Materials, JAERI. The Sub-Committee carried out collaborative analyses among eleven participating laboratories for the certification of the Certified Reference Materials (CRMs), JAERI-G5 and G6, after developing and evaluating analytical methods during the period of September 1989 to March 1992. The certified values were given for ash, boron and silicon in the CRM based on the collaborative analysis. The values for ten elements (Al, Ca, Cr, Fe, Mg, Mo, Ni, Sr, Ti, V) were not certified, but given for information. Preparation, homogeneity testing and chemical analyses for certification of reference materials were described in this paper. (author) 52 refs

  14. Effect of Pre-deformation and Annealing on Cube Texture in High Purity Aluminum Foils%预变形及退火对高纯铝箔立方织构的影响

    Institute of Scientific and Technical Information of China (English)

    刘楚明; 张新明; 周鸿章; 陈志永; 邓运来

    2001-01-01

    The effect of pre-deformation and annealing on cube texture of high parity aluminium foils has been investigated by means of TEM and method of orientation distribution functions (ODFs).The results showed that the magnitude of stored energy in Al foils was affected by predeformation and annealing,which influenced the precipitation of impurities Fe and Si.While Fe and Si resolve into the Al matrix before final annealing,it can increase the number of cube nucleus during the low temperature period of two-stages annealing.The nucleus can prefer to grow at high temperature stage of final annealing,and the cube texture in high purity Al foils became very strong.%应用TEM和晶体取向分布函数方法研究和分析了预变形和退火工艺对高纯铝箔立方织构的影响。研究结果表明,预变形及退火主要通过影响晶体内的储存能大小,来影响Fe、Si的析出过程,影响成品箔材中立方织构{100}〈001〉取向密度的大小。由于成品退火前Fe、Si能充分固溶在铝基体中,成品低温退火阶段可促使Fe、Si析出,增加立方取向晶粒的形核率,使成品在高温退火阶段晶粒沿立方取向择优长大,大大增加了高纯铝箔中立方织构的比例。

  15. Ikke bare porno på mobilen

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    2013-01-01

    Den britiske børne- og ungdomsforsker professor Sonia Livingstone ved London School of Economics viser gennem en række interviews, at billeder af eksplicitte sexhandlinger er en velkendt del af den ungdommelige cirkulation af ’hverdagspornografisk’ materiale (Ringrose et al. 2012). ’Sexting’ er...... altså ikke bare porno på en mobilplatform. Det er handlinger og værgestrategier, som unge piger er nødt til at forholde sig til i hverdagen, mens drengene umiddelbart ser ud til at slippe relativt let udenom den chikane, der kan ligge i ’sexting’....

  16. Chirality in Bare and Passivated Gold Nanoclusters

    CERN Document Server

    Garzon, I L; Rodrigues-Hernandez, J I; Sigal, I; Beltran, M R; Michaelian, K

    2002-01-01

    Chiral structures have been found as the lowest-energy isomers of bare (Au$_{28}$ and Au$_{55}) and thiol-passivated (Au$_{28}(SCH$_{3})$_{16}$ and Au$_{38}$(SCH$_{3}$)$_{24}) gold nanoclusters. The degree of chirality existing in the chiral clusters was calculated using the Hausdorff chirality measure. We found that the index of chirality is higher in the passivated clusters and decreases with the cluster size. These results are consistent with the observed chiroptical activity recently reported for glutahione-passivated gold nanoclusters, and provide theoretical support for the existence of chirality in these novel compounds.

  17. 高纯锗(HPGe)γ谱仪测定铀矿石中镭的方法研究%The Experiment Study on the Radium Measurment in Uranium ore with High Purity Germanium(HPGe) γSpectrometer

    Institute of Scientific and Technical Information of China (English)

    薛志伟; 高明明; 乔宁强; 王强; 朱晓贤

    2014-01-01

    为了改善由样品密度不同、厚度不同引起的测量误差,笔者采用压片法制样,然后密封于样品盒达到平衡,通过152 Eu对外界的电磁干扰进行内标校正,在高纯锗( HPGe)γ谱仪上测定铀矿石中镭的含量。测定结果的相对标准偏差( RSD/%)为2.43%,与射气法结果进行比较,相对误差在-5.31%~6.62%之间,方法的精密度和准确度均能满足实际生产需求,可操作性强,简便快速。%In order to reduce the measurement error caused by different sample thickness and density , the author uses compression method to get detection sample .The sample is sealed in a sample box to achieve balance , then we measure the radium content of uranium ore by using High purity germanium (HPGe) γspectrometer. The result is corrected by 152 Eu to avoid the electromagnetic disturbances .The relative standard deviation ( RSD%) of the determination results is 2.43%.Comparing with the emanation method results , the relative error are between -5.31%~6.62%.The method is able to meet the demands due to its advantages of easy operation and rapidness , the high precision and accuracy .

  18. Dynamics and control designs for internal thermally coupled distillation columns with different purities, Part 1: Open loop dynamic behaviors

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The open loop dynamic behaviors of internal thermally coupled distillation column with four different purities (low-,moderate-, high- and very high-purity) are studied. These dynamic behaviors are characterized by strong asymmetric non-linearity, high sensitivity to operation conditions change and distinct inverse response. With the increase of purity, these dynamic behaviors are intensified and become more complex, which easily lead to the mismatch between linear model and plant and also change the relationship between manipulated and controlled variables.

  19. Study on technology of preparing high-purity α-Al2O3 powder%制备高纯度α-Al2O3粉体的工艺研究

    Institute of Scientific and Technical Information of China (English)

    吴沙沙; 王俊勃; 江燕; 王彦龙; 赵文杰; 杨尔慧

    2015-01-01

    The precursor Al(OH)3 of Al2 O3 were prepared by chemical precipitation with aluminium ni-trate and sal volatile under different concentration of aluminium nitrate,and Al2 O3 powders were getted through calcining precursor at different temperature. The powders were analyzed by the TG-DTG,XRD, BET and SEM. The results showed that the calcination temperature was an important factor to the crystal form of the Al2 O3 powder. The powders with good dispersing were obtained when the concentration of alu-minium nitrate was 0. 1 mol/ L. The sphere-like α-alumina powders with high purity were obtained when the calcination temperature was 1 200 ℃.%以硝酸铝和碳酸铵为原料,采用化学沉淀法,在不同硝酸铝浓度下制备 Al2 O3的前驱体 Al(OH)3,再经不同温度煅烧得到 Al2 O3粉体。利用 TG-DTG、XRD、BET 及 SEM 等分析手段对粉体的性能进行了表征。结果表明,煅烧温度对 Al2 O3的晶型有着重要的影响,硝酸铝浓度为0.1 mol/ L 时制备出的粉体分散性较好,经1200℃煅烧能制备出纯度较高的形貌类似球形的α-Al2 O3粉体。

  20. Differential scanning calorimetry method for purity determination: A case study on polycyclic aromatic hydrocarbons and chloramphenicol

    Energy Technology Data Exchange (ETDEWEB)

    Kestens, V., E-mail: vikram.KESTENS@ec.europa.eu [European Commission - Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel (Belgium); Zeleny, R.; Auclair, G.; Held, A.; Roebben, G.; Linsinger, T.P.J. [European Commission - Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, 2440 Geel (Belgium)

    2011-09-20

    Highlights: {yields} Purity assessment of polycyclic aromatic hydrocarbons and chloramphenicol by DSC. {yields} DSC results compared with traditional purity methods. {yields} Different methods give different results, multiple method approach recommended. {yields} DSC sensitive to impurities that have similar structures as main component. - Abstract: In this study the validity and suitability of differential scanning calorimetry (DSC) to determine the purity of selected polycyclic aromatic hydrocarbons and chloramphenicol has been investigated. The study materials were two candidate certified reference materials (CRMs), 6-methylchrysene and benzo[a]pyrene, and two different batches of commercially available highly pure chloramphenicol. The DSC results were compared with those obtained by other methods, namely gas and liquid chromatography with mass spectrometric detection, liquid chromatography with diode array detection, and quantitative nuclear magnetic resonance. The purity results obtained by these different analytical methods confirm the well-known challenges of comparing results of different method-defined measurands. In comparison with other methods, DSC has a much narrower working range. This limits the applicability of DSC as purity determination method, for instance during the assignment of the purity value of a CRM. Nevertheless, this study showed that DSC can be a powerful technique to detect impurities that are structurally very similar to the main purity component. From this point of view, and because of its good repeatability, DSC can be considered as a valuable technique to investigate the homogeneity and stability of candidate purity CRMs.

  1. 废铁屑还原软锰矿制备高纯硫酸锰工艺研究%Preparation of High Purity Manganese Sulfate from the Reduction of Pyrolusite Using Scrap Iron as the Reductant

    Institute of Scientific and Technical Information of China (English)

    蔡振勇; 易清风; 刘汉勇; 方明略; 龚学华; 符国庆

    2011-01-01

    研究了采用废铁屑作为还原剂,在稀硫酸介质中湿法还原软锰矿制备硫酸锰的工艺过程.通过单因素实验确定最佳工艺参数,结果表明:当Fe/MnO2的摩尔比为0.78∶1,H2SO4/MnO2的摩尔比为2.1∶1,反应温度50℃,反应时间80 min时,锰的浸出率在95%以上.加入碳酸钙中和调节溶液pH值至5~6,使溶液中的铁、铝等杂质离子水解为氢氧化铁、氢氧化铝等沉淀除去,加入硫化钡使浸出溶液中的重金属离子以硫化物沉淀除去,减压过滤得到硫酸锰粗滤液,向粗滤液中加入二氟化锰使溶液中的Ca2+、Mg2+等离子生成氟化物沉淀,然后溶液经过静置过滤得到硫酸锰净化液,滤液经浓缩、结晶制备硫酸锰产品.经检测产品纯度在99%以上,杂质含量低于国家标准.%In this paper, the leaching of manganese sulfate from pyrolusite with scrap iron as a reductant in dilute sulfuric acid solution was studied. Optimal parameters that affect the leaching efficiency of manganese sulfate were determined by the single factor method. The results shows that the leaching rate of manganese can reach more than 95%under the condition of Fe to MnO2 molar ratio of 0.78, H2SO4 to MnO2 molar ratio of 2.1, reaction temperature 50°C, reaction time 80min. Calcium carbonate was added to the leaching solution to adjust pH 5 ~ 6 so that iron^aluminum and other impurities were removed by becoming iron hydroxide、aluminum hydroxide and other precipitations. Heavy metal ions were removed by adding barium sulfide to the leaching solution to form sulfide precipitations. After being filtrated, manganese difluoride was added to the filtrate to precipitate Ca2+ 、Mg2+ and other impurities. After standing, the solution was then filtrated and high purity manganese sulfate solution was obtained. Crystallized manganese sulfate was obtained after being concentrated. Manganese sulfate purity can reach more than 99% and impurity contents were lower than those

  2. Enhanced Detection of Low-Abundance Host Cell Protein Impurities in High-Purity Monoclonal Antibodies Down to 1 ppm Using Ion Mobility Mass Spectrometry Coupled with Multidimensional Liquid Chromatography.

    Science.gov (United States)

    Doneanu, Catalin E; Anderson, Malcolm; Williams, Brad J; Lauber, Matthew A; Chakraborty, Asish; Chen, Weibin

    2015-10-20

    The enormous dynamic range of proteinaceous species present in protein biotherapeutics poses a significant challenge for current mass spectrometry (MS)-based methods to detect low-abundance HCP impurities. Previously, an HCP assay based on two-dimensional chromatographic separation (high pH/low pH) coupled to high-resolution quadrupole time-of-flight (QTOF) mass spectrometry and developed in the author's laboratory has been shown to achieve a detection limit of about 50 ppm (parts per milion) for the identification and quantification of HCPs present in monoclonal antibodies following Protein A purification.1 To improve the HCP detection limit we have explored the utility of several new analytical techniques for HCP analysis and thereby developed an improved liquid chromatography-mass spectrometry (LC-MS) methodology for enhanced detection of HCPs. The new method includes (1) the use of a new charge-surface-modified (CSH) C18 stationary phase to mitigate the challenges of column saturation, peak tailing, and distortion that are commonly observed in the HCP analysis; (2) the incorporation of traveling-wave ion mobility (TWIM) separation of coeluting peptide precursors, and (3) the improvement of fragmentation efficiency of low-abundance HCP peptides by correlating the collision energy used for precursor fragmentation with their mobility drift time. As a result of these improvements, the detection limit of the new methodology was greatly improved, and HCPs present at a concentration as low as 1 ppm (1 ng HCP/mg mAb) were successfully identified and quantified. The newly developed method was applied to analyze two high-purity mAbs (NIST mAb and Infliximab) expressed in a murine cell line. For both samples, low-abundance HCPs (down to 1 ppm) were confidently identified, and the identities of the HCPs were further confirmed by targeted MS/MS experiments. In addition, the performance of the assay was evaluated by an interlaboratory study in which three independent

  3. Usefulness of preprocedure high-sensitivity C-reactive protein to predict death, recurrent myocardial infarction, and stent thrombosis according to stent type in patients with ST-segment elevation myocardial infarction randomized to bare metal or drug-eluting stenting during primary percutaneous

    DEFF Research Database (Denmark)

    Schoos, Mikkel Malby; Kelbæk, Henning; Kofoed, Klaus F;

    2011-01-01

    It is unknown whether high-sensitivity C-reactive protein (hs-CRP) predicts outcome depending on implanted stent type. We investigated the prognostic value of hs-CRP in relation to type of stent implanted in patients with ST-segment elevation myocardial infarction (STEMI). Immediately before...... primary percutaneous coronary intervention (pPCI), 301 patients had blood drawn. Patients were categorized according to hs-CRP levels and combination of hs-CRP (=2 vs >2 mg/L) and stent type (bare metal stent [BMS] vs drug-eluting stent [DES]). Hs-CRP >2 mg/L (median, hazard ratio 2.7, 95% confidence...

  4. Usefulness of preprocedure high-sensitivity C-reactive protein to predict death, recurrent myocardial infarction, and stent thrombosis according to stent type in patients with ST-segment elevation myocardial infarction randomized to bare metal or drug-eluting stenting during primary percutaneous

    DEFF Research Database (Denmark)

    Schoos, Mikkel Malby; Kelbæk, Henning; Kofoed, Klaus F;

    2011-01-01

    It is unknown whether high-sensitivity C-reactive protein (hs-CRP) predicts outcome depending on implanted stent type. We investigated the prognostic value of hs-CRP in relation to type of stent implanted in patients with ST-segment elevation myocardial infarction (STEMI). Immediately before...... primary percutaneous coronary intervention (pPCI), 301 patients had blood drawn. Patients were categorized according to hs-CRP levels and combination of hs-CRP (≤2 vs >2 mg/L) and stent type (bare metal stent [BMS] vs drug-eluting stent [DES]). Hs-CRP >2 mg/L (median, hazard ratio 2.7, 95% confidence...

  5. A purity monitoring system for liquid argon calorimeters

    International Nuclear Information System (INIS)

    For liquid argon calorimeters electronegative impurities dissolved in the medium degrade the detector response and deteriorate the energy resolution, especially at high energies. A concept for a purity monitoring system for liquid argon calorimeters has been developed and is presented here. Special combined monitors of 241Am- and 207Bi-cells are used to monitor the concentration of impurities. The working principle as well as results from test measurements are discussed

  6. Purity Relative to Classes of Finitely Presented Modules

    CERN Document Server

    Mehdi, Akeel Ramadan

    2012-01-01

    We investigate purities determined by classes of finitely presented modules including the correspondence between purities for left and right modules. We show some cases where purities determined by matrices of given sizes are different. Then we consider purities over finite-dimensional algebras, giving a general description of the relative pure injectives which we make completely explicit in the case of tame hereditary algebras.

  7. Purity assessment of condensed tannin fractions by nuclear magnetic resonance (NMR) spectroscopy

    Science.gov (United States)

    Unambiguous investigation of condensed tannin (CT) structure-activity relationships in biological systems requires the use of highly enriched CT fractions of defined chemical purity. Purification of CTs from Sorghum bicolor, Trifolium repens, Theobroma cacao, Lespedeza cuneata, Lotus pedunculatus, a...

  8. High-purity control of internal thermally coupled distillation columns based on nonlinear Wave model%基于非线性Wave模型的内部热耦合塔高纯控制方案

    Institute of Scientific and Technical Information of China (English)

    丛琳; 刘兴高; 周叶翔

    2012-01-01

    为了解决高纯内部热耦合精馏塔( ITCDIC)的强非线性特性给控制器的设计带来较大困难的问题,将非线性Wave理论运用到内部热耦合精馏塔的控制设计中.首先根据浓度曲线的特性提出了浓度波形的描述函数.其次根据波形描述函数以及物料守恒关系推导出波速公式.最后将Wave理论与一般模型控制(GMC)结合起来,建立了基于Wave模型的一般模型控制(WGMC).在苯-甲苯物系的实例研究中与传统的基于数据模型的一般模型控制(TGMC)进行比较.研究结果表明,WGMC在伺服控制和干扰控制的表现都明显优于TGMC,WGMC控制方案较传统的一般模型控制方案更加稳定可靠.%To solve the problem that high-purity internal thermally coupled distillation columns (ITCDIC) present strong nonlinear dynamics which troubles the controller design, nonlinear wave theory is introduced into the control design of ITCDIC. First, the describing function of the profile of concentration is proposed according to the characteristics of the concentration curve. Then, the wave velocity is derived from describing function of the concentration profile and component mass balance of each stage. Finally, combining the Wave model with the generic model control (GMC) a generic model control based on the Wave model (WGMC) is proposed. Compared with data-based generic model control (TGMC) in benzene-toluene system, WGMC performs more excellently both in servo control and regulatory control and it is more stable and efficient than the generic model control scheme.

  9. Efficacy of a high-purity factor IX concentrate in hemophilia B patients undergoing surgery Eficácia do concentrado de alta pureza do fator IX em pacientes cirúrgicos portadores de hemofilia B

    Directory of Open Access Journals (Sweden)

    Vesa Rasi

    2002-04-01

    Full Text Available A plasma derived, high purity, solvent-detergent treated and subsequently nanofiltered factor IX concentrate (BEMOFIL was evaluated in 19 hemophilia B patients, including four with severe, thirteen with mild or moderate type of disease and two hemophilia B carriers undergoing 31 surgical procedures. The mean in vivo recovery was 52 %, range 36 - 76 %. The mean preoperative plasma factor IX activity after the initial loading dose was 0.86 IU mL-1, range 0.59 - 1.32 IU mL-1. In eight major orthopedic procedures, the mean usage of factor IX was 44600 IU or 574 IU kg-1 during the hospital stay, mean 11.6 days. Thromboprophylaxis was not used. The hemostatic efficacy was evaluated good in all cases and there were no thromboembolic complications. In conclusion, BEMOFIL used as bolus dosing was found to be safe and effective in achieving hemostasis in subjects with hereditary F IX deficiency undergoing surgery.O concentrado de fator IX ( Bemofil , um derivado plasmático de alta pureza tratado com solventes- detergente e nano-filtrado , foi avaliado em 19 pacientes portadores de Hemofilia B .Quatro pacientes apresentavam a forma grave da moléstia, 13 a forma leve e moderada e dois portadores em um total de 31 atos cirúrgicos.A recuperação média "in vivo" foi de 52% (36-76%. A atividade plasmática média pré-operatória do fator IX após a dose inicial foi de 0,86 UI ml -1 , média de 0,59 - 1,32 UI ml-1. Em oito procedimentos ortopédicos extensos , a média de utilização do fator IX foi de 44.600 UI ou 574 UI kg -1 durante a hospitalização que teve a média de 11,6 dias. A tromboprofilaxia não foi utilizada. A eficácia hemostática avaliada em todos os casos foi boa ,e não ocorreu nenhum tipo de complicação tromboembólica. Concluímos que o Bemofil em bolus foi considerado seguro e eficaz para a hemostasia em pacientes portadores de hemofilia B que necessitam de um procedimento cirúrgico.

  10. Estimating purity in terms of correlation functions

    CERN Document Server

    Prosen, T; Znidaric, M; Prosen, Tomaz; Seligman, Thomas H.; Znidaric, Marko

    2003-01-01

    We prove a rigorous inequality estimating the purity of a reduced density matrix of a composite quantum system in terms of cross-correlation of the same state and an arbitrary product state. Various immediate applications of our result are proposed, in particular concerning Gaussian wave-packet propagation under classically regular dynamics.

  11. Pristine Purity : New Political Parties in Canada

    NARCIS (Netherlands)

    Lucardie, Anthonie

    2007-01-01

    Success sells better than failure; hence new parties receive very little attention from political scientists as long as they remain marginal and fail to win seats in Parliament. Yet in the margins of the party system, they may maintain the pristine purity of political principles and ideas better tha

  12. Preparation of High-Purity Sponge Bismuth from Copper Converter Flue Dusts by Hydrometallurgical Process%全湿法从铜转炉白烟灰中制备高纯海绵铋

    Institute of Scientific and Technical Information of China (English)

    廖婷; 陈白珍; 陈亚

    2012-01-01

    采用“酸浸—沉铋—脱砷—置换”工艺处理铜转炉白烟灰制备高纯海绵铋.首先以0.5 mol·L-1 H2SO4溶液为浸出剂对白烟灰进行一次酸浸,在60℃、液固比为4∶1的条件下反应3h,可将大部分Zn,Cd,Cu,Fe等可溶性元素进行分离,同时铋得到富集.然后用H2SO4-NaCl 混合溶液对一次酸浸渣进行二次酸浸,本实验对二次酸浸工艺参数进行了优化,结果表明:在温度为60℃、硫酸浓度为2 mol·L-1、氯离子浓度为2.5 mol·L-1、液固比为2∶1的条件下进行一段逆流循环浸出,铋的浸出率达到95.2%,酸浸液中铋含量为15.88 g·L-1.用氨水调节酸浸液的pH值在0.5 ~3.0之间选择性沉铋,能有效的将Bi与Cu,Sb,Pb等元素分离,铋的回收率达到96%,得到的含铋沉淀中铋、砷含量分别为36.2%,19.1%.该沉淀铋品位较低,砷含量太高,以2 mol·L-NaOH溶液为脱砷剂对该含铋沉淀进行脱砷处理,30 min后,砷的脱除率达到97.05%,而铋品位提高到57.28%.脱砷后的含铋物料经硝酸溶解后,用铁粉进行置换,结果发现:在铁过量系数为1.5的条件下反应20 min,铋的置换率达98%,制取的海绵铋纯度高达90%以上.%The process of "acid leaching — bismuth precipitation — dearsenication — replacement" was used for preparation of high-purity sponge bismuth from copper converter flue dusts. Firstly, 0.5 mol·L-1H2SO4 solution was used as leaching agent, under the condition of 60 ℃ water bath, the liquid-solid ratio 2:1, leaching 3 h, so that most solubility element such as Zn, Cd, Cu, Fe could be separated and bismuth get enrichment. Secondly, H2SO4-NaCl blend solution was used as leaching agent for the second leaching process to leaching the once acid leaching residue, and the operation conditions of the second leaching process were optimist. The results showed that a counter-current circulation leaching under the condition of 60 ℃ water bath, 2 mol·L-1 H2SO4 , 2. 5 mol

  13. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  14. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  15. Pair emission from bare magnetized strange stars

    CERN Document Server

    Melrose, D B; Peres-Menezes, D

    2006-01-01

    The dominant emission from bare strange stars is thought to be electron-positron pairs, produced through spontaneous pair creation (SPC) in a surface layer of electrons tied to the star by a superstrong electric field. The positrons escape freely, but the electrons are directed towards the star and quickly fill all available states, such that their degeneracy suppresses further SPC. An electron must be reflected and gain energy in order to escape, along with the positron. Each escaping electron leaves a hole that is immediately filled by another electron through SPC. We discuss the collisional processes that produce escaping electrons. When the Landau quantization of the motion perpendicular to the magnetic field is taken into account, electron-electron collisions can lead to an escaping electron only through a multi-stage process involving higher Landau levels. Although the available estimates of the collision rate are deficient in several ways, it appears that the rate is too low for electron-electron colli...

  16. Inference of conversion and purity for ETBE reactive distillation

    Directory of Open Access Journals (Sweden)

    Tian Yu-Chu

    2000-12-01

    Full Text Available Reactive distillation (RD, an unconventional and attractive technique, has been applied in fuel ether production. A typical application of RD is the synthesis of the widely used methyl tert-butyl ether (MTBE. RD has also been found to have potential to produce high quality ethyl tert-butyl ether (ETBE, a potential alternative to MTBE. A RD process integrates conventional reaction and separation into a single unit, resulting in extra complexity and dual process objectives, i.e. maximization of reactant conversion and purity of products. The conversion and the purity are thus important variables to be controlled in RD of ETBE. Unfortunately, both of them are not economically and reliably available for closed-loop control. This study aims to develop an effective method to infer the conversion and the purity from multiple temperature measurements that are easily available on-line and in real time. Nonlinear inferential models are recommended for ETBE synthesis with a ten-stage pilot scale RD column. The models are two-variable third-order regressive models, in which the temperature measurements of the reboiler and the bottom reactive section are employed. Experimental design, model identification, and model testing are also investigated.

  17. Initial Stages of Recrystallization in Aluminum of Commercial Purity

    DEFF Research Database (Denmark)

    Hansen, Niels; Bay, Bent

    1979-01-01

    by the FeAl3 particles present in the commercial aluminum as impurities. The nucleation temperatures determined by high voltage electron microscopy and transmission electron microscopy decrease markedly when the initial grain size is decreased both after 50 and 90 pct cold rolling; a less pronounced......In commercial aluminum with a purity of 99.4 pct, the formation and growth of recrystallization nuclei were studied by techniques such asin-situ annealing in a high voltage electron microscope, transmission electron microscopy and light microscopy. Sample parameters were the initial grain size (370...

  18. Spectral Purity Enhancement via Polyphase Multipath Circuits

    OpenAIRE

    Mensink, Eisse; Klumperink, Eric; Nauta, Bram

    2004-01-01

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits by using polyphase multipath circuits? The basic idea behind polyphase multipath circuits is to split the nonlinear circuits into two or more paths and exploit phase differences between these paths to cancel undesired distortion products. It turns out that it is very well possible to use polyphase multipath circuits to cancel distortion products produced by a nonlinear circuit. Unfortunately, there...

  19. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  20. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses.

    Science.gov (United States)

    Basir, Amir; Gründeman, Paul; Moll, Frans; van Herwaarden, Joost; Pasterkamp, Gerard; Nijland, Reindert

    2016-01-01

    Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus adherence to Dyneema Purity® was tested and compared with currently used cardiovascular prostheses. We compared adhesion of S. aureus to Dyneema Purity® (1 membrane-based and 1 yarn-composed patch) with 5 clinically used yarn-composed polyester and membrane-based expanded polytetrafluoroethylene patches. Patches were contaminated with S. aureus bacteria and bacterial adherence was quantified. S. aureus adherence was also visualized in flow conditions. Overall, bacterial adherence was higher on yarn-composed prosthesis materials, with a rough surface, than on the membrane-based materials, with a smooth surface. Adherence to Dyneema Purity® materials was non-inferior to the currently used materials. Therefore, patches of Dyneema Purity® might be attractive for use in cardiovascular applications such as catheter-based heart valves and endovascular prostheses by their good mechanical properties combined with their noninferiority regarding bacterial adhesion. PMID:27583703

  1. Superconducting radio-frequency cavities made from medium and low-purity niobium ingots

    Science.gov (United States)

    Ciovati, Gianluigi; Dhakal, Pashupati; Myneni, Ganapati R.

    2016-06-01

    Superconducting radio-frequency cavities made of ingot niobium with residual resistivity ratio (RRR) greater than 250 have proven to have similar or better performance than fine-grain Nb cavities of the same purity, after standard processing. The high purity requirement contributes to the high cost of the material. As superconducting accelerators operating in continuous-wave typically require cavities to operate at moderate accelerating gradients, using lower purity material could be advantageous not only to reduce cost but also to achieve higher Q 0-values. In this contribution we present the results from cryogenic RF tests of 1.3–1.5 GHz single-cell cavities made of ingot Nb of medium (RRR = 100–150) and low (RRR = 60) purity from different suppliers. Cavities made of medium-purity ingots routinely achieved peak surface magnetic field values greater than 70 mT with an average Q 0-value of 2 × 1010 at 2 K after standard processing treatments. The performances of cavities made of low-purity ingots were affected by significant pitting of the surface after chemical etching.

  2. A Syntactic Study on Bare Infinitive and Infinitival to

    Institute of Scientific and Technical Information of China (English)

    LIU Jing

    2014-01-01

    Infinitives which consist of bare infinitive and infinitival to are imperative in linguistic studies. And both of the two kinds of infinitives do not indicate person, tense and number. This research aims to analyze the properties, similarities and differ-ences between bare infinitive and infinitival to from the perspective of syntax. Thus, it enables us to attain a uniform characteriza-tion of the infinitival to and bare infinitive on the syntactic level and help us to understand these two kinds of infinitives better.

  3. Surface purity control during XMASS detector refurbishment

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Kazuyoshi, E-mail: kenkou@icrr.u-tokyo.ac.jp [Kamioka observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu, 506-1205 (Japan); Kavl Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba, 277-8582 (Japan)

    2015-08-17

    The XMASS project aims at detecting dark matter, pp and {sup 7}Be solar neutrinos, and neutrino less double beta decay using large volume of pure liquid xenon. The first physics target of the XMASS project is to detect dark matter with 835 kg liquid xenon. After the commissioning runs, XMASS detector was refurbished to minimize the background contribution mainly from PMT sealing material and we restarted data taking in November 2013. We report how we control surface purity, especially how we prevent radon daughter accumulation on the detector copper surface, during XMASS detector refurbishment. The result and future plan of XMASS are also reported.

  4. A xenon gas purity monitor for EXO

    CERN Document Server

    Dobi, A; Herrin, S; Odian, A; Prescott, C Y; Rowson, P C; Ackerman, N; Aharmin, B; Auger, M; Barbeau, P S; Barry, K; Benitez-Medina, C; Breidenbach, M; Cook, S; Counts, I; Daniels, T; DeVoe, R; Dolinski, M J; Donato, K; Fairbank, W; Farine, J; Giroux, G; Gornea, R; Graham, K; Gratta, G; Green, M; Hagemann, C; Hall, K; Hallman, D; Hargrove, C; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Lacey, J; Leonard, D S; LePort, F; Mackay, D; MacLellan, R; Mong, B; Diez, M Montero; Muller, A R; Neilson, R; Niner, E; O'Sullivan, K; Piepke, A; Pocar, A; Pushkin, K; Rollin, E; Sinclair, D; Slutsky, S; Stekhanov, V; Twelker, K; Voskanian, N; Vuilleumier, J -L; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2011-01-01

    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

  5. EAARL Bare Earth Topography-Fire Island National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model or DEM) of Fire Island National Seashore was produced from remotely-sensed,...

  6. EAARL Coastal Topography--Pearl River Delta 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Pearl River Delta in Louisiana and Mississippi was produced from remotely...

  7. EAARL Coastal Topography--Chandeleur Islands, Louisiana, 2010: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the Chandeleur Islands, Louisiana, was produced from remotely...

  8. EAARL Coastal Topography--Northeast Barrier Islands 2007: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northeast coastal barrier islands in New York and New Jersey was produced from...

  9. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the northern Gulf of Mexico barrier islands and Naval Live Oaks was produced from...

  10. EAARL Topography-Vicksburg National Millitary Park 2008: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the Vicksburg National Military Park in Mississippi was produced from remotely...

  11. Bare and effective fluid description in brane world cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Casilla 307, Santiago (Chile); Lepe, Samuel; Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile)

    2010-03-15

    An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fluid can cross the barrier {omega} {sub eff}=-1. (orig.)

  12. High-purity hydrogen generation in a microfabricated 23 wt % Ag-Pd membrane device integrated with 8:1 LaNi{sub 0.95}Co{sub 0.05}O{sub 3}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Wilhite, B.A.; Weiss, S.E.; Ying, J.Y.; Jensen, K.F. [Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, 66-501 Cambridge, MA 02139 (United States); Schmidt, M.A. [Department of Electrical Engineering and Computer Science, and Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2006-07-04

    Micromembranes integrating nanometer-scale Pd films with complex oxide methanol-reforming catalysts demonstrate high-purity hydrogen generation. Washcoating of an 8:1 LaNi{sub 0.95}Co{sub 0.05}O{sub 3}/Al{sub 2}O{sub 3} catalyst serves the dual purposes of preventing thin-film disintegration upon direct exposure to methanol while providing improved selectivity and conversion of methanol to hydrogen through partial oxidation. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  13. Killing, letting die and the bare difference argument.

    Science.gov (United States)

    Perrett, Roy W

    1996-04-01

    I believe that there is no intrinsic moral difference between killing and letting die. That is, there is no difference that depends solely on the distinction between an act and an omission. I also believe that we can reasonably establish this thesis by appeal to the Bare Difference Argument. The form of this argument involves considering two imaginary cases in which there are no morally relevant differences present, save the bare difference that one is a case of killing and one a case of letting die. But in the pair of cases under consideration this bare difference makes no moral difference. Hence it cannot be that the bare difference between killing and letting die is in itself a morally important difference. Winston Nesbitt has recently argued that the Bare Difference Argument fails because "the examples produced typically possess a feature which makes their use in this context illegitimate, and that when modified to remove this feature, they provide support for the view which they were designed to undermine". I argue that Nesbitt misunderstands the logic of the Bare Difference Argument and that accordingly his objections are mistaken.

  14. EAARL Topography - Vicksburg National Military Park 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Segura, Martha; Yates, Xan

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Vicksburg National Military Park in Mississippi, acquired on March 6, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed

  15. EAARL Coastal Topography-Pearl River Delta 2008: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Miner, Michael D.; Yates, Xan; Bonisteel, Jamie M.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the University of New Orleans (UNO), Pontchartrain Institute for Environmental Sciences (PIES), New Orleans, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Pearl River Delta in Louisiana and Mississippi, acquired March 9-11, 2008. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the

  16. EAARL Coastal Topography-Chandeleur Islands, Louisiana, 2010: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Bonisteel-Cormier, Jamie M.; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Nagle, David B.; Vivekanandan, Saisudha; Yates, Xan; Klipp, Emily S.

    2010-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived bare-earth (BE) and submerged topography datasets were produced collaboratively by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of a portion of the Chandeleur Islands, acquired March 3, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  17. EAARL Coastal Topography - Northern Gulf of Mexico, 2007: Bare Earth

    Science.gov (United States)

    Smith, Kathryn E.L.; Nayegandhi, Amar; Wright, C. Wayne; Bonisteel, Jamie M.; Brock, John C.

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Gulf Coast Network, Lafayette, LA; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. The purpose of this project is to provide highly detailed and accurate datasets of select barrier islands and peninsular regions of Louisiana, Mississippi, Alabama, and Florida, acquired on June 27-30, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using

  18. EAARL Coastal Topography - Northeast Barrier Islands 2007: Bare Earth

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Sallenger, A.H.; Wright, C. Wayne; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived bare earth (BE) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the northeast coastal barrier islands in New York and New Jersey, acquired April 29-30 and May 15-16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom

  19. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness.

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-19

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV-visible spectral region (360-610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10-24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor.

  20. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness.

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-19

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV-visible spectral region (360-610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10-24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor. PMID:27383631

  1. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-01

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV–visible spectral region (360–610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10–24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor.

  2. ORSPHERE: CRITICAL, BARE, HEU(93.2)-METAL SPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Margaret A. Marshall

    2013-09-01

    In the early 1970’s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an attempt to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950’s (HEU-MET-FAST-001). The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVA I experiments. “The very accurate description of this sphere, as assembled, establishes it as an ideal benchmark for calculational methods and cross-section data files.” (Reference 1) While performing the ORSphere experiments care was taken to accurately document component dimensions (±0. 0001 in. for non-spherical parts), masses (±0.01 g), and material data The experiment was also set up to minimize the amount of structural material in the sphere proximity. A three part sphere was initially assembled with an average radius of 3.4665 in. and was then machined down to an average radius of 3.4420 in. (3.4425 in. nominal). These two spherical configurations were evaluated and judged to be acceptable benchmark experiments; however, the two experiments are highly correlated.

  3. Highly Accurate Sensor for High-Purity Oxygen Determination Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this STTR Phase I effort, Los Gatos Research (LGR) and Professor Scott Sanders (Mechanical Engineering Department, University of Wisconsin ? Madison) propose to...

  4. High Purity m-Cresol Obtained by Combination of Urea and Calcium Bromide Method%尿素-溴化钙联用分离制高纯度间甲酚

    Institute of Scientific and Technical Information of China (English)

    侯颖; 眭贤明; 杨立荣; 吴坚平; 徐刚

    2011-01-01

    The urea complex method was used to separate m-cresol from the mixture of w-cresol and p-cresol (molar ratio of m-cresol to p-cresol was 66.8:33.2). The recovery of m-cresol reached 65% and the purity of m-cresol was above 99% when the molar ratio of urea to m-cresol was 1.4 and the same amount of toluene as m-cresol was used as solvent. The filtrate from above process was treated by calcium bromide method and was suitable for separation by the urea complex method. After being separated by the urea complex method again, the total recovery of m-cresol could increase from 65% to 85%.%以物质的量之比为66.8∶33.2的间甲酚和对甲酚的混酚为原料,采用尿素络合法分离间甲酚.以与间甲酚等物质的量的甲苯为溶剂,在尿素与间甲酚物质的量之比为1.4的条件下分离后,间甲酚回收率为65%,纯度为99%.采用溴化钙络合法对尿素法分离间甲酚所产生的废液进行再次分离,得到混酚原料,然后采用尿素法进一步分离,间甲酚的回收率可由65%提高至85%左右.

  5. Surface photon emissivity of bare strange stars

    OpenAIRE

    Cheng, KS; Harko, T.

    2003-01-01

    We consider the bremsstrahlung surface photon emissivity of strange quark stars, by systematically taking into account the effects of the multiple scatterings of highly relativistic quarks in a dense medium (the Landau-Pomeranchuk-Migdal effect). Because of interference between amplitudes of nearby interactions, the bremsstrahlung emissivity from a strange star surface is suppressed for frequencies smaller than a critical frequency. The range of the suppressed frequencies is a function of the...

  6. Conditions for strictly purity-decreasing quantum Markovian dynamics

    International Nuclear Information System (INIS)

    The purity, Tr(ρ 2), measures how pure or mixed a quantum state ρ is. It is well known that quantum dynamical semigroups that preserve the identity operator (which we refer to as unital) are strictly purity-decreasing transformations. Here, we provide an almost complete characterization of the class of strictly purity-decreasing quantum dynamical semigroups. We show that in the case of finite-dimensional Hilbert spaces, a dynamical semigroup is strictly purity-decreasing if and only if it is unital, while in the infinite dimensional case, unitality is only sufficient

  7. Green nanochemistry: metal oxide nanoparticles and porous thin films from bare metal powders.

    Science.gov (United States)

    Redel, Engelbert; Petrov, Srebri; Dag, Omer; Moir, Jonathon; Huai, Chen; Mirtchev, Peter; Ozin, Geoffrey A

    2012-01-01

    A universal, simple, robust, widely applicable and cost-effective aqueous process is described for a controlled oxidative dissolution process of micrometer-sized metal powders to form high-purity aqueous dispersions of colloidally stable 3-8 nm metal oxide nanoparticles. Their utilization for making single and multilayer optically transparent high-surface-area nanoporous films is demonstrated. This facile synthesis is anticipated to find numerous applications in materials science, engineering, and nanomedicine.

  8. A proposed bare tether experiment on board a sounding rocket

    OpenAIRE

    Fujii, Hironori; OYAMA, Kohichiro; Sasaki, Susumu; Yamagiwa, Yoshiki; Cho, Mengu; Sanmartín Losada, Juan Ramón; Charro, Mario; Heide, Erik J. van der; Kruijff, Michiel; Lebreton, Jean-Pierre; Hilgers, Alain

    2005-01-01

    A sounding rocket experiment is proposed to carry out two experiments by the conductive bare-tether; 1) the test of the OML (Orbital-Motion-Limited) theory to collect electron, and II) the test of techniques to determine (neutral) density profile in critical E-layer. The main driver of the mission is provide a space tether technology experiment in low-Earth-Orbit (LEO) deploying a long tape tether in space and verify the performance of the bare electrodynamic tape tether. The sounding rocket ...

  9. Semantic coherence in English accusative-with-bare-infinitive constructions

    DEFF Research Database (Denmark)

    Jensen, Kim Ebensgaard

    2013-01-01

    Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative-with-bare-infinitive constru......Drawing on usage-based cognitively oriented construction grammar, this paper investigates the patterns of coattraction of items that appear in the two VP positions (the VP in the matrix clause, and the VP in the infinitive subordinate clause) in the English accusative...... relations of English accusatives-with-bare-infinitives through the relations of semantic coherence between the two VPs....

  10. ’Crossing a Bare Common’

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    2005-01-01

    Emerson critics to construe his exorbitant rhetorical style as somehow perfectly conducive to achieving the sense of transcendence that his effort to convey an American’s experience of the sublime would have to involve. Characteristically, Emerson’s highly charged eloquence on the sublime is more often...... than not described as a ‘sublime rhetoric’. From the stock of rhetorical tropes the most favoured by Emerson and picked out as the trademark of his rhetorical sublimity critics mention in particular his use of hyperbole, chiasmus and metalepsis. Common to all three tropes is said to be their ability......’s The Romantic Sublime (1976), Harold Bloom’s Agon: A Theory of Revisionism (1982) and Ruin the Sacred Truths (1989) and Jan Rosiek’s magisterial Maintaining the Sublime: Heidegger and Adorno (2000)....

  11. Optical coupling of bare optoelectronic components and flexographically printed polymer waveguides in planar optronic systems

    Science.gov (United States)

    Wang, Yixiao; Wolfer, Tim; Lange, Alex; Overmeyer, Ludger

    2016-05-01

    Large scale, planar optronic systems allowing spatially distributed functionalities can be well used in diverse sensor networks, such as for monitoring the environment by measuring various physical quantities in medicine or aeronautics. In these systems, mechanically flexible and optically transparent polymeric foils, e.g. polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET), are employed as carrier materials. A benefit of using these materials is their low cost. The optical interconnections from light sources to light transmission structures in planar optronic systems occupy a pivotal position for the sensing functions. As light sources, we employ the optoelectronic components, such as edgeemitting laser diodes, in form of bare chips, since their extremely small structures facilitate a high integration compactness and ensure sufficient system flexibility. Flexographically printed polymer optical waveguides are deployed as light guiding structures for short-distance communication in planar optronic systems. Printing processes are utilized for this generation of waveguides to achieve a cost-efficient large scale and high-throughput production. In order to attain a high-functional optronic system for sensing applications, one of the most essential prerequisites is the high coupling efficiency between the light sources and the waveguides. Therefore, in this work, we focus on the multimode polymer waveguide with a parabolic cross-section and investigate its optical coupling with the bare laser diode. We establish the geometrical model of the alignment based on the previous works on the optodic bonding of bare laser diodes and the fabrication process of polymer waveguides with consideration of various parameters, such as the beam profile of the laser diode, the employed polymer properties of the waveguides as well as the carrier substrates etc. Accordingly, the optical coupling of the bare laser diodes and the polymer waveguides was simulated

  12. Hydrogen-induced cracking of commercial purity titanium

    International Nuclear Information System (INIS)

    Slow straining of compact tension specimens of commercial-purity titanium has been employed for assessing the likelihood of failure due to hydrogen pick-up in titanium containers for nuclear fuel waste disposal. Results indicate that slow crack growth occurs by a ductile tearing process at low hydrogen concentrations. No fast crack growth occurs at such hydrogen levels, apparently because ductile collapse relaxes the stresses and prevents the attainment of a sufficiently high stress intensity for fast crack initiation. Fast propagation of a brittle crack was observed only at hydrogen concentrations above a critical value that depended upon the material involved and the orientation of the crack relative to the manufactured microstructure. An empirical relationship suggests that the higher the strength of the titanium involved the lower is the critical hydrogen level for brittle failure. Both the distribution of residual β-phase and the texture of the fabricated material influence the susceptibility of a particular specimen orientation to fast fracture. (author)

  13. 电感耦合等离子体质谱法测定高纯镍板中砷锡锑铅铋%Determination of arsenic, tin, antimony, lead and bismuth in high-purity nickel plate by inductively coupled plasma mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    赵琎; 胡建春

    2015-01-01

    采用10 mL硝酸(1+1)低温加热至沸溶解0.1000 g试样,在优化仪器参数的基础上,通过选择合适的同位素以避免质谱干扰和采用标准加入法绘制校准曲线以消除基体效应,建立了电感耦合等离子体质谱法( ICP-MS)测定高纯镍板中砷、锡、锑、铅、铋的方法。各元素校准曲线的相关系数为0.9992~0.9999,方法检出限为0.009~0.047μg/g。方法应用于高纯镍板实际样品分析,测得结果的相对标准偏差( RSD, n=9)为2.4%~5.4%,加标回收率为95%~106%。方法测定高纯镍板实际样品的结果与原子吸收光谱法( AAS)相吻合。%0. 100 0 g of sample was dissolved with 10 mL of nitric acid (1+1) by heating from low temperature to boiling. Based on the optimization of instrumental parameters, the mass spectrometry interference was avoided by selecting proper isotope, and the calibration curve was plotted by standard addition method to eliminate the matrix effect. Consequently, a determination method of arsenic, tin, antimony, lead and bismuth in high-purity nickel plate was established by inductively coupled plasma mass spectrometry ( ICP-MS ) . The correlation coefficient of calibration curve for each element was between 0. 999 2 and 0. 999 9 . The detection limit of method was 0. 009-0. 047 μg/g. The proposed method was applied to the analysis of high purity nickel plate actual sample. The rela-tive standard deviation (RSD, n=9) was 2. 4%-5. 4%, and the recoveries were between 95% and 106%. The determination results of high purity nickel plate actual sample were consistent with those obtained by atomic absorp-tion spectrometry ( AAS) .

  14. Double Glow Plasma Hydrogen-free Carburizing on Commercial Purity Titanium

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gaohui; PAN Junde; HE Zhiyong; ZHANG Pingze; GAO Yuan; XU Zhong

    2005-01-01

    A carburized layer with special physical and chemical properties was formed on the surface of commercial purity titanium by a double glow plasma hydrogen-free carburizing technique. High-purity netlike solid graphite was used as a raw material and commercial purity titanium was used as the substrate material. Argon gas was used as the working gas. The carburized layer can be obviously observed under a microscope. X-ray diffraction indicates that TiC phase with higher hardness and dissociate state carbon phase was formed in the carburized layer. The glow discharge spectrum (GDS) analysis shows that the carbon concentration distributes gradiently along the depth of carburized layer. The surface hardness of the substrate increases obviously. The hardness distributes gradiently from the surface to inner of carburized layer. The friction coefficient reduces by more than 1/2, the ratio wear rate decreases by above three orders of magnitude. The wear resistance of the substrate material is improved consumedly.

  15. Fashion Brand Purity and Firm Performance

    Directory of Open Access Journals (Sweden)

    Jin-hui Zheng

    2013-01-01

    Full Text Available A large number of prior empirical research and case studies used qualitative methodology to discuss the fashion brand dilution resulting from consumer base extension from the target group(s to the nontarget groups and its impacts. From a different perspective, this paper establishes a dynamic brand dilution and performance model, demonstrating how dynamic changes of sales volumes involving the two consumer groups affect the degree of brand dilution and the performance of the brand. We incorporate the factor “brand purity” to the model as a quantitative measure of brand dilution level that affects firm annual revenue and profit change comprehensively in iteration. Our model suggests that fashion brands, especially luxury brands, can be easily diluted under the pressure of firm growth, and the brands suffer the significant negative impact on their revenues and profit. While increasing sales volume can aggravate the negative consequences, brand purity can be increased through limiting the consumer base to the target group only.

  16. Purity calculation method for event samples with two the same particles

    CERN Document Server

    Kuzmin, Valentin

    2016-01-01

    We present a method of the two dimensional background calculation for an analysis of events with two the same particles observing by a detector of high energy physics. Usual two dimensional integration is replaced by an approximation of a specially constructed one-dimensional function. The value of the signal events is found by the subtraction of the background from the value of all selected events. It allows to calculate the purity value of the selected events sample. The procedure does not require a hypothesis about background and signal shapes. The nice performance of the purity calculation method is shown on Monte Carlo examples of double J/psi samples.

  17. A comparison of the cyclic deformation behaviour of two purities of zirconium

    International Nuclear Information System (INIS)

    Pronounced cyclic softening occurs from the start of testing in commercial - purity zirconium, while only slight cyclic softening occurs in high - purity zirconium. In both cases, the cyclic softening is associated with a decrease in the effective stress as determined from the shape of the hysteresis loops. The occurrence of this cyclic softening is associated with an increase in the mobility of the screw dislocations and with the formation of dipolar walls, which observations indicate that an important portion of the hardening produced by interstitial solutes in zirconium is associated with an increase in the Peierls stress for the glide of the screw dislocations

  18. A comparison of the cyclic deformation behaviour of two purities of zirconium

    International Nuclear Information System (INIS)

    Pronounced cyclic softening occurs from the start of testing in commercial-purity zirconium, while only slight cyclic softening occurs in high-purity zirconium. In both cases, the cyclic softening is associated with a decrease in the effective stress as determined from the shape of the hysteresis loops. The occurrence of this cyclic softening is associated with an increase in the mobility of the screw dislocations, and with the formation of dipolar walls. The observations indicate that an important portion of the hardening produced by interstitial solutes in zirconium is associated with an increase in the Peierls stress for the glide of the screw dislocations. (author)

  19. Determination of continuous variable entanglement by purity measurements

    CERN Document Server

    Adesso, G; Illuminati, F; Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-01-01

    We classify the entanglement of two-mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on purity measurements.

  20. Determination of continuous variable entanglement by purity measurements.

    Science.gov (United States)

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-02-27

    We classify the entanglement of two-mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on measurements of purity. PMID:14995815

  1. Determination of continuous variable entanglement by purity measurements

    OpenAIRE

    Adesso, G.; Serafini, A.; Illuminati, F.

    2004-01-01

    We classify the entanglement of two--mode Gaussian states according to their degree of total and partial mixedness. We derive exact bounds that determine maximally and minimally entangled states for fixed global and marginal purities. This characterization allows for an experimentally reliable estimate of continuous variable entanglement based on measurements of purity.

  2. BARE retrotransposons are translated and replicated via distinct RNA pools.

    Directory of Open Access Journals (Sweden)

    Wei Chang

    Full Text Available The replication of Long Terminal Repeat (LTR retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.

  3. Basic science of nuclear medicine the bare bone essentials

    CERN Document Server

    Lee, Kai H

    2015-01-01

    Through concise, straightforward explanations and supporting graphics that bring abstract concepts to life, the new Basic Science of Nuclear Medicine—the Bare Bone Essentials is an ideal tool for nuclear medicine technologist students and nuclear cardiology fellows looking for an introduction to the fundamentals of the physics and technologies of modern day nuclear medicine.

  4. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  5. 从钒酸钠溶液中深度除磷制备高纯V2O5的研究%Removing Phosphorus from Sodium Vanadate Solution for Production of High-Purity V2O5

    Institute of Scientific and Technical Information of China (English)

    段冉; 李青刚

    2011-01-01

    P was the main impurity in vanadium production since the formation of complexes with V and ammonium in the sodium vanadate solution during the process of extracting vanadium from stone coal, which resulted in unqualified V2OS product. The complete removal of phosphorous from sodium vanadate solution obtained from the strip liquor of ion exchange in the extraction of vanadium from stone coal by magnesium salt precipitation was studied. The effects of addition amount of magnesium salt, pH, temperature and time on the removal of P were investigated, and the mechanism for the removal of P was also proposed. The results showed that the removal of P reached 96% under weak base condition. Other impurities, such as Si, Fe and As were also effectively removed. The optimum conditions for P removal were as follows; 12% feed solution of magnesium salt addition amount at 45 ℃ and pH 10.0 for SO min. The ammonium salt was then added into filtrate at 50 ℃ after filtration, and the obtained ammonium vanadate was calcined in Muffle furnace at 500 ℃ for 2 h. The purity of final product V2O5 reached 99.9%.%随着科技的发展,钒应用领域不断地扩大,对钒产品纯度的要求也越来越高,所以对高纯度精钒制备技术的研究是很有必要的.磷是影响精钒质量的一种主要杂质,在石煤提钒过程中.钒酸钠溶液中的磷会与铵、钒形成复杂的络合物(杂多酸),当达到一定量时,影响五氧化二钒的质量,造成钒产品中磷含量超标.以石煤提钒过程的离子交换解析液为料液,主要针对石煤提钒离子交换工艺中磷的行为,提出了镁盐沉淀法从钒酸钠溶液中深度除磷,制备高纯V2O5的研究.分析了除磷过程中的机制,研究了镁盐加入量、pH、温度、时间等因素对除磷效果的影响.实验结果表明:在弱碱性条件下,镁盐法可有效除去钒酸钠溶液中的磷,除磷率达到96%以上,同时亦可有效除去钒酸钠溶液中的Si

  6. ICP-AES与分光光度法测定高纯氢氧化钠中三氧化二铁含量%ICP-AES and spectrophotometric determination of high purity sodium hydroxide content sodium hydroxide content of Fe2O3

    Institute of Scientific and Technical Information of China (English)

    孙德化; 马文雁

    2011-01-01

    This paper introduces thc use of AtomScan Advantage type inductively coupled piasma emission spectrometer analysis of high purity sodium hydroxide in the Fe2O3 content, and compared with conventional spectrophotomctry, show that the LCP-AES method in the production of the supenority of the analysis.%本文着重介绍利用 AtomScan Advantage 型电感耦合等离子体发射光谱仪分析高纯氢氧化钠中 Fe2O3 含量,并与传统分光光度法相比较,表明 ICP-AES 法在生产分析中的优越性.

  7. 热水解沉淀法分离基体钛-ICP-MS法测定高纯钛中痕量元素%Separaton of titanium matrix by pyrohydrolysis-deposition method-determination of trace amounts of elements in high purity titanium by ICP-MS

    Institute of Scientific and Technical Information of China (English)

    李娜; 刘冰心; 张丽; 刘英; 童坚; 臧慕文

    2012-01-01

    建立了热水解沉淀分离基体-电感耦合等离子体质谱测定高纯钛中Li,Cr,Mn,Ni,Co,Ga,Sr,Zr,Mo痕量元素分析方法,并对ICP-MS工作参数及条件进行了优化和选择.利用钛热水解成为Ti(OH)4沉淀,达到分离基体的目的,然后用ICP-MS法直接检测.方法的检出限在0.002 ~0.1ng/mL之间,测定下限为0.01 ~0.5ng/mL,各元素的回收率在90.9%~115.6%之间.利用该方法对高纯钛样品进行分析,结果表明,其精密度和准确度均满足痕量分析的要求.%A new method for the determination of trace amounts of elements Li, Cr, Mn, Ni, Co, Ga, Sr, Zr, Mo in high-purity titanium by ICP-MS with separation of titanium matrix by pyrohydrolysis-deposition method. ICP-MS operating parameters and conditions are optimized. Because titanium was hydrolyzed to titanium hydroxide, matrix titanium could be separated by the method and directly detected by ICP-MS. Detection limit and minimum limit of determination of the method were 0.002 ~ 0. lng/mL and 0.01 ~ 0. 5ng/mL, respectively. The recoveries ranged from 90.9% to 115.6%. Using the method to analyze the high-purity titanium, the results show that the method has good accuracy and precision, and it can meet the requirements of trace analysis.

  8. State-independent purity and fidelity of quantum operations

    Science.gov (United States)

    Kong, Fan-Zhen; Zong, Xiao-Lan; Yang, Ming; Cao, Zhuo-Liang

    2016-04-01

    The purity and fidelity of quantum operations are of great importance in characterizing the quality of quantum operations. The currently available definitions of the purity and fidelity of quantum operations are based on the average over all possible input pure quantum states, i.e. they are state-dependent (SD). In this paper, without resorting to quantum states, we define the state-independent (SI) purity and fidelity of a general quantum operation (evolution) in virtue of a new density matrix formalism for quantum operations, which is extended from the quantum state level to quantum operation level. The SI purity and fidelity gain more intrinsic physical properties of quantum operations than state-dependent ones, such as the purity of a one-qubit amplitude damping channel (with damping rate 1) is 1/2, which is in line with the fact that the channel is still a nonunitary operation described by two Kraus operators rather than a unitary one. But the state-dependent Haar average purity is 1 in this case. So the SI purity and fidelity proposed here can help the experimentalists to exactly quantify the implementation quality of an operation. As a byproduct, a new measure of the operator entanglement is proposed for a quantum evolution (unitary or nonunitary) in terms of the linear entropy of its density matrix on the orthonormal operator bases (OOBs) in Hilbert-Schmidt space.

  9. Effects of plasma parameters on increasing the purity of nitrogen atom encapsulated fullerene in an RF plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ahamed, Jamal Uddin, E-mail: ahamed.jamal@cu.ac.bd [Department of Applied Physics, Electronics and Communication Engineering, University of Chittagong, Chittagong 4331 (Bangladesh); Hatakeyama, Rikizo [Department of Electronic Engineering, Tohoku University, Sendai 8980-8579 (Japan)

    2012-11-01

    Highlights: Black-Right-Pointing-Pointer We examine the effects of plasma parameters on increasing the purity of N-C{sub 60}. Black-Right-Pointing-Pointer RF plasma parameters play a significant role on the efficient synthesis of N-C{sub 60}. Black-Right-Pointing-Pointer N{sup +} impinging on the sublimated fullerenes enhances the synthesis of N-C{sub 60}. Black-Right-Pointing-Pointer The purity is found to increase with the increase of RF power. Black-Right-Pointing-Pointer Comparatively a high purity of about 0.08% of N-C{sub 60} has been synthesized. - Abstract: Relatively high purity of nitrogen atom encapsulated fullerene (N-C{sub 60}) has been synthesized by an electron beam superimposed radio frequency (RF) discharge plasma method. Nitrogen species are characterized by an optical emission spectroscopy (OES); and a relationship between optical emission spectra and the purity of N-C{sub 60} has been examined. It is observed that the increased amount of nitrogen molecule ions impinging on the sublimated fullerenes enhance the synthesis of N-C{sub 60}. Here, it is cleared that the efficient synthesis of N-C{sub 60} is possible by controlling the parameters of electron beam superimposed RF plasma. As a consequence, comparatively high purity of about 0.08% of N-C{sub 60} has been obtained.

  10. Paleomagnetism of the Miocene dikes in Bare Mountain, southwest Nevada: Implications for regional tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Gillett, S.L.; Karlin, R.E.; Schweickert, R.A. (Univ. of Nevada, Reno, NV (United States). Dept. of Geological Sciences)

    1993-04-01

    Paleomagnetic studies of N-striking Miocene quartz latite dikes (13.9 Ma), within Proterozoic and Paleozoic sedimentary rocks of Bare Mountain, have been conducted in an effort to determine the sense of post-middle Miocene tectonic tilting and rotation in the Bare Mountain region. A total of 56 oriented samples of dikes and wallrocks were collected from Tarantula Canyon (TC) and south of Joshua Hollow (JH), where the dikes intruded N-dipping Mississippian-Devonian limestone beds. Progressive thermal demagnetization and principal component analyses reveal a stable high temperature component of remanent magnetization that is carried by magnetite or hematite in different samples. Petrographic investigations, combined with thermal demagnetization analysis, indicate that magnetite is a primary phase and that hematite is secondary. Hematitic alteration in both wallrocks and dikes is probably hydrothermal following intrusion as the mean direction of both minerals overlap. The in situ mean magnetization directions from all dikes exhibit negative inclinations that correspond to a Tertiary reversed field. The data indicate that magnetization acquisition in the wallrocks and dikes postdates tilting of the beds and the no major remagnetization event has occurred since the intrusion. The results from TC imply that there has been no significant rotation of the northeast part of Bare Mountain since [minus]14 Ma. The authors further suggest that the E-W structural trends of Proterozoic and Paleozoic rocks at Bare Mountain are older than the middle Miocene dikes. Paleomagnetic data from dikes of JH show steeper inclinations and westerly declinations compared to the dike of TC. There are two interpretations to explain the differences: The dikes may have formed at different times in the same magmatic event and the directional differences are due to secular variation. Alternatively, the dikes at JH were tilted slightly to the north around a sub-horizontal axis.

  11. Thermomechanical fatigue behavior of coated and bare nickel-based superalloy single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chataigner, E.; Remy, L.

    1996-12-31

    The thermal-mechanical fatigue behavior of chromium-aluminum coated [001] single crystals of AM1, a nickel-base superalloy for turbine blades, is studied using a diamond shape cycle from 600 to 1,100 C. Comparison with bare specimens does not show any significant difference in thermal-mechanical fatigue nor in isothermal low cycle fatigue at high temperature. Metallographic observations on fracture surfaces and longitudinal sections of specimens tested to fatigue life or to a definite fraction of expected life have shown that the major crack tends to initiate from casting micropores in the sub-surface area very early in bare and coated specimens, under low cycle fatigue or thermal-mechanical fatigue. But the interaction between oxidation and fatigue cracking seems to play a major role. A simple model proposed by Reuchet and Remy has been identified for this single crystal superalloy. Its application to the life prediction under low cycle fatigue and thermal-mechanical fatigue for bare and coated single crystals with different orientations is shown.

  12. Models for calculating phreatic water evaporation on bare and Tamarix-vegetated lands

    Institute of Scientific and Technical Information of China (English)

    HU Shunjun; TIAN Changyan; SONG Yudong; CHEN Xiaobing; LI Yuetan

    2006-01-01

    Groundwater is the main source of water consumption of natural vegetation in arid regions.It is an effective approach to study ecological water demand of natural vegetation by phreatic evaporation.In order to study the ecological water demand of Tarim river basin, based on the observation data of phreatic evaporation on bare lands at the Aksu Water Balance Experimental station from 1989 to 1996, by analyzing the relationship of phreatic evaporation,depth of phreatic surface and evaporation of water,taking the limit rate of phreatic evaporation as the control condition, and based on the objective law that the relation between phreatic evaporation and evaporation of water is nonlinear, we establish models for calculating phreatic evaporation on bare land,which can fully reflect the law of phreatic evaporation in the Tarim river basin. According to the data of depth of phreatic surface and soil moisture when pheratic level decline is caused just by evapotranspiration on Tamarix-vegetated land from 2003 to 2004, we calculate the amount of phreatic evaporation and set up models for calculating phreatic evaporation on Tamarix- vegetated land. Phreatic evaporation on bare land and Tamarix-vegetated land could be transformed each other by a Tamarix vegetation conversion coefficient. The test results show that the calculation accuracy of the models is high and the models are suitable for Tarim river basin.

  13. Study of THz surface waves (TSW) on bare and coated metal surface

    Science.gov (United States)

    Gong, Mufei

    Scope and Method of Study. The focus of the research was to investigate the propagation characteristics (such as field distribution, attenuation and group velocity) of terahertz surface waves on bare and dielectric coated metal surface. The experiment was carried out on a modified standard terahertz time-domain spectroscopy system. Surface waves were coupled into the metal surface using the parallel plate waveguide coupling mechanism. The picosecond terahertz pulses were generated and detected using the Grischkowsky photo-conductive transmitter and antenna driven by a femtosecond laser. Findings and Conclusions. Surface waves at microwave and terahertz frequencies are weakly guided on bare metal surface due to the high metal conductivity. Detailed wave coupling analysis and experiment has shown that on a bare metal surface, the majority of energy remains to be uncoupled freely propagating waves. The spatial extent of the terahertz surface wave collapses two orders of magnitude upon the addition of the sub-wavelength dielectric layer on the metal surface. Simple theory in terahertz range gives an accurate explanation to this effect. Direct experimental measurements of the terahertz surface wave on an aluminum surface covered with a 12.5 mum thick dielectric layer have completely characterized the wave. The measurements of the frequency-dependent exponential fall-off of the evanescent wave from the surface agree well with theory.

  14. Preparation of Conjugated Linoleic Acid of High Purity and Its Apparent Kinetic Characteristics During Formation%高纯度共轭亚油酸的制备及其转化过程的表观动力学特征

    Institute of Scientific and Technical Information of China (English)

    唐向阳; 郭诤; 张根旺

    2002-01-01

    共轭亚油酸是一种具有多种生理活性和潜在应用前景的脂肪酸.研究了可用于规模化生产的高纯度共轭亚油酸的合成方法及其纯化的工艺路线和条件.以红花油为原料,通过脲包纯化、共轭化制备出纯度高达950  0的共轭亚油酸,总收率在480  0以上.并对以葵花油为原料的亚油酸转化为共轭亚油酸的反应动力学进行了研究,建立了其表观动力学模型,为工业设计提供了依据.%Conjugated linoleic acid (CLA) is a fatty acid with physiological activities and potential application prospect. This paper focuses on the method of synthesis of conjugated linoleic acid of high purity and the process line and conditions for its purification that can be used in large-scale production. CLA of more than 950  0 purity was prepared by means of urea adduct purification and conjugation using safflower oil as material. The total recovery of the product adds up to more than 480  0. The reactive kinetics about linoleic acid from sunflower oil converted into CLA was investigated, and its apparent kinetic model was also established, which can be used as a base for industrial designs.

  15. Effects of Purity on Dynamics of Multipartite Entanglement

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-Shi

    2008-01-01

    We study the effects of purity on entanglement dynamics of a multipartite system in cavity QED. Three two-level atoms A, B and C are initially prepared in an entangled state and locally coupled with independent cavities a, b and c, respectively. We consider the effects of purity of atomic initial state on the entanglement evolution of both the systems of atoms and cavities. It is found that depending on the purity of atomic initial state, the entanglement of atoms (cavities) may or may not exhibit the sudden death (birth) phenomenon.

  16. Radar reflectivity of bare and vegetation-covered soil

    Science.gov (United States)

    Ulaby, F. T.; Dobson, M. C.; Bradley, G. A.

    1981-01-01

    Radar sensitivity to soil moisture content has been investigated experimentally for bare and vegetation-covered soil using detailed spectral measurements obtained by a truck-mounted radar spectrometer in the 1-8 GHz band and by airborne scatterometer observations at 1.6, 4.75, and 13.3 GHz. It is shown that radar can provide quantitative information on the soil moisture content of both bare and vegetation-covered soil. The observed soil moisture is in the form of the soil matric potential or a related quantity such as the percent of field capacity. The depth of the monitored layer varies from 1 cm for very wet soil to about 15 cm for very dry soil.

  17. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Science.gov (United States)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-01

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the charged-interfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits short-range in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  18. Assembling Bare Au Nanoparticles at Positively Charged Templates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the chargedinterfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits shortrange in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  19. The Political Animal: Species-Being and Bare Life

    Directory of Open Access Journals (Sweden)

    Laura Hudson

    2008-01-01

    Full Text Available Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  20. Nuda vida y goce. // Bare life and jouissance.

    OpenAIRE

    Laura Arias.

    2010-01-01

    From the point of view that connects politics and psychoanalysis, the aim of this essay is to investigate the causes of the annihilation of the subject in the totalitarian regimes, making him a victim of power, reduced to a bare life. This question leads us to analyze the jouissance within the frame of a regime that proposes the unification of a universal jouissance. These questions are considered to be relevant in the field that makes possible the intersection between politics and subjectivi...

  1. Photon emissivity of the electrosphere of bare strange stars

    OpenAIRE

    Harko, T.; Cheng, KS

    2005-01-01

    We consider the spectrum, emissivity, and flux of the electromagnetic radiation emitted by the thin electron layer (the electrosphere) at the surface of a bare strange star. In particular, we carefully consider the effect of the multiple and uncorrelated scattering on the radiation spectrum (the Landau-Pomeranchuk-Migdal effect), together with the effect of the strong electric field at the surface of the star. The presence of the electric field strongly influences the radiation spectrum emitt...

  2. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    OpenAIRE

    kashmera ashish khedkkar safaya; Rekha Lathi

    2012-01-01

    This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS) camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  3. Dynamic Vision Sensor Camera Based Bare Hand Gesture Recognition

    Directory of Open Access Journals (Sweden)

    kashmera ashish khedkkar safaya

    2012-05-01

    Full Text Available This Paper proposes a method to recognize bare hand gestures using dynamic vision sensor (DVS camera. DVS camera only responds asynchronously to pixels that have temporal changes in intensity which different from conventional camera. This paper attempts to recognize three different hand gestures rock, paper and scissors and using those hand gestures design mouse free interface.   Keywords: Dynamic vision sensor camera, Hand gesture recognition

  4. The Political Animal: Species-Being and Bare Life

    OpenAIRE

    Laura Hudson

    2008-01-01

    Marxism has been justifiably skeptical of animal rights. Indeed, deep ecology and animal-rights discourse are, in their native habitats, deeply problematic and self-contradictory. But recent theories of “bare life,” when brought into dialogue with Marx’s concept of species-being, offer a perspective from which animal rights discourse and Marxism share a common political horizon.

  5. Field Investigations of Evaporation from a Bare Soil

    Science.gov (United States)

    Evett, Steven Roy

    Selected components of the water and energy balances at the surface of a bare clay loam were measured at 57 locations in a 1 ha field. Spatial and temporal variability of these components were also studied. Components included evaporation, irrigation, moisture storage, sensible heat flux and long wave radiation. Sub-studies were conducted on irrigation uniformity under low pressure sprinklers; and, on steel versus plastic microlysimeters (ML) of various lengths. An energy balance model of evaporation, requiring minimal inputs, was developed and validated giving an r ^2 value of 0.78. Model improvements included an easy method of accurately estimating soil surface temperature at many points in a field, and an empirically fitted transfer coefficient function for the sensible heat flux from the reference dry soil. The omission of soil heat flux and reflected shortwave radiation terms was shown to reduce model accuracy. Steel ML underestimated cumulative evaporation compared to plastic ML at 20 and 30 cm lengths. Cumulative evaporation increased with ML length. The 10 and 20 cm ML were too short for use over multiple days but 30 cm ML may not be long enough for extended periods. Daily net soil heat flux for steel ML averaged 44% higher than that for both plastic ML and undisturbed field soil. Christiansen's uniformity coefficient (UCC) was close to 0.83 for each of 3 irrigations when measured by both catch cans and by profile water contents. But UCC for the change in storage due to irrigation averaged only 0.43 indicating than the high uniformity of profile water contents was more due to surface and subsurface redistribution than to the uniformity of application. Profile water contents and catch can depths were time invariant across at least 3 irrigations. Midday soil surface temperatures and daily evaporation were somewhat less time invariant. Variogram plots for evaporation and surface temperature showed mostly random behavior. Relative variograms represented well

  6. Determination of Purity by Differential Scanning Calorimetry (DSC).

    Science.gov (United States)

    Brown, M. E.

    1979-01-01

    An exercise is presented which demonstrates the determination of sample purity by differential scanning calorimetry. Data and references are provided to enable the exercise to be carried out as a dry-lab experiment. (BB)

  7. Electrophoresis for the analysis of heparin purity and quality

    OpenAIRE

    Volpi, Nicola; Maccari, Francesca; Suwan, Jiraporn; Linhardt, Robert J.

    2012-01-01

    The adulteration of raw heparin with oversulfated chondroitin sulfate (OSCS) in 2007–2008 produced a global crisis resulting in extensive revisions to the pharmacopeia monographs and prompting the FDA to recommend the development of additional methods for the analysis of heparin purity. As a consequence, a wide variety of innovative analytical approaches have been developed for the quality assurance and purity of unfractionated and low-molecular-weight heparins. This review discusses recent d...

  8. Purity Relative to Classes of Finitely Presented Modules

    OpenAIRE

    Mehdi, Akeel Ramadan

    2013-01-01

    Any set of finitely presented left modules defines a relative purity for left modules and also apurity for right modules. Purities defined by various classes are compared and investigated,especially in the contexts of modules over semiperfect rings and over tame hereditary, andmore general, finite-dimensional algebras. Connections between the indecomposable relativelypure-injective modules and closure in the full support topology (a refinement of theZiegler spectrum) are described.Duality bet...

  9. Use of TerraSAR-X data to retrieve soil moisture over bare soil agricultural fields

    OpenAIRE

    Baghdadi, N.; Aubert, M.; Zribi, M.

    2012-01-01

    The retrieval of the bare soil moisture content from TerraSAR-X data is discussed using empirical approaches. Two cases were evaluated: 1) one image at low or high incidence angle and 2) two images, one at low incidence and one at high incidence. This study shows by using three databases collected between 2008 and 2010 over two study sites in France (Orgeval and Villamblain) that TerraSAR-X is a good remote sensing tool for the retrieving of surface soilmoisture with accuracy of about 3% (rms...

  10. Factors affecting ice crystal purity during freeze concentration process for urine treatment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Freeze concentration has great potential in treating wastewaters containing soluble pollutions. It is important for freeze concentration process to produce ice crystals with large size and high purity. In this work raw urines of 4660-7914 mg/L in COD,512.71-872.41 mg/L in NH3-N and 22600-28800μs/cm in e lectric conductivity were studied. Urines were frozen by a digital refrigerated circulator bath. Ice crystals were purified by ice-water steep and vacuum filtration. The COD,NH3-N,and electric conductivity levels of the melted ices were measured to reflect ice crystal purity. Effects of coolant temperature, ice crystal shape, initial solution temperature, solution concentration, ice seeding, re-crystallization process and crystallization time on ice crystal purity were analyzed. The results show that an appropriate coolant temperature, suspended ice crystals,an initial solution temperature of about 6 C, introduction of seed ice, addition of re-crystallization process. And crystallization time of less than 30 min are in favor of producing ice crystals with hith purity.Under such conditions, more than 99 percent of inorganic salts, COD and NH3-N sources in raw urine could be removed.

  11. Phospholipid bilayer formation at a bare Si surface

    DEFF Research Database (Denmark)

    Gutberlet, T.; Steitz, R.; Fragneto, G.;

    2004-01-01

    Neutron reflectivity was applied to monitor in situ the adsorption of small unilamellar phospholipid vesicles on a solid bare hydrophilic Si interface. The obtained reflectivity curves are consistent with the rupture and fusion model for the adsorption of phosphatidylcholine vesicles to solid...... interfaces. The results show details of the adsorbed bilayer system at ångström resolution and indicate the presence of a thin ∼6 Å thick water leaflet that separates the bilayer from the Si surface. The resolved structural details provide the basis for further investigation of processes such as adsorption...

  12. Development of generator-cooling hydrogen purity improvement system using hydrogen absorbing alloy; Suiso kyuzo gokin ni yoru hatsudenkinai suiso jundo kojo system no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Y.; Sato, J.; Haruki, N.; Kogi, T.; Okuno, Y. [The Kansai Electric Power Co. Inc., Osaka (Japan); Takeda, H.; Wakisaka, Y. [The Japan Steel Works, Ltd., Tokyo (Japan); Fujita, T. [Mitsubishi Electric Corp., Tokyo (Japan)

    1997-01-31

    A generator-cooling hydrogen purity improvement system was developed by utilizing hydrogen absorbing and discharging functions of hydrogen storage alloy. For demonstration test with an actual machine, four elements, Ca, Ni, Mm and Al, were used as hydrogen storage alloys. To treat hydrogen gas with a wide range of purity and reduce hydrogen gas feed, flow operation for hydrogen purity improvement, batch operation, and recycle operation for maintaining the hydrogen purity were performed. As a result of the generator-cooling hydrogen purity improvement demonstration test, it was found that the hydrogen purity can be enhanced from 97.69% before operation to 99.9% after operation for 104 hours and to 99.95% after operation for 140 hours. The hydrogen recovery rates during flow test and batch test were between 92 and 95%. For the hydrogen purity maintaining test, it was confirmed that the high hydrogen purity of 99.9% has been continuously maintained for 140 days, and that the hydrogen recovery rate was over 99%. 2 refs., 15 figs., 3 tabs.

  13. 盐湖卤水硼镁分离工艺及高纯氧化镁的制备%Separation technique for boron and magnesium from salt lake brine and preparation of high-purity magnesium oxide

    Institute of Scientific and Technical Information of China (English)

    于培峰; 杨喜云; 徐徽; 石西昌; 陈亚; 颜果春

    2013-01-01

    Using salt lake brine with high boron, magnesium and lithium as raw material, the boron was separated from magnesium and lithium with sulfate acid and ion exchange resin, and the magnesium was separated by precipitation with ammonia. The effects of pH value, temperature, time, resin amount, flowing rate of brine and ratio of height to diameter (H/D) of the column on boron removal were investigated under static and dynamic conditions. The optimum process conditions of boron removal are obtained. The results show that the boron removal ratio reaches 95%under the optimum process conditions. The boron concentration of brine has a significant effect on the content of boron in magnesium hydroxide. The content of boron in magnesium hydroxide increases from 0.04 mg/g to 8.82 mg/L with boron increasing from 4.54 mg/L to 1 200 mg/L. Using brine containing 4.54 mg/L boron as raw material to prepare magnesium hydroxide followed by calcination at 1 500℃for 2 h, 99.8%magnesium oxide is obtained.%  以富含硼、镁、锂的盐湖卤水为原料,采用硫酸和离子交换法联合提硼,实现硼与镁、锂分离;采用氨法沉淀镁实现镁与锂的分离.分别用静态法和动态法研究卤水pH值、吸附温度、吸附时间、树脂用量、卤水流速、交换柱高径比对硼提取率的影响,确定提硼最佳工艺条件,硼提取率达95%以上.研究卤水硼浓度对氢氧化镁中硼含量的影响.结果表明:当卤水中的硼浓度由4.54 mg/L增加到1200 mg/L时,氢氧化镁中硼含量由0.04 mg/g增加到8.82 mg/g.对硼浓度4.54 mg/L的卤水用氨法沉淀制备氢氧化镁,在1500℃下煅烧得到氧化镁,其纯度为99.8%.

  14. Application of Plasma Emission Detector in Determination of Trace Neon in High Purity Helium%等离子体发射检测器在检测高纯氦气中微量氖气的应用

    Institute of Scientific and Technical Information of China (English)

    胡树国; 张体强

    2016-01-01

    Trace neon in helium prepared by gravimetric method was determined by gas chromatography with plasma emission detector and discharge ionization detector. Sensitivity and repeatability of trace neon in different detector were compared. The results showed that the detection sensitivity of PED was higher, the linear range of neon was 0.03-0.3μmol/mol,the correlation coefficients (r2) was 1.000,the detection limit was less than 1 nmol/mol,the RSD was less than 2%(n=6). By comparing the data of atmosphere pressure ion mass spectrometry,the reliability of the results was verified. The determination of trace neon in helium byplasma emission detector may decrease the uncertainty of neon reference material,which lays the foundation of development of high precision trace neon standard material.%采用等离子发射检测器(PED)和氦离子放电检测器(DID)对重量法制备的氦气中微量氖气进行了检测,对比了微量氖气在两种检测器上的灵敏度和重复性.结果显示,PED对氖气的检测灵敏度较高,氖气含量在0.03~0.3μmol/mol范围与响应值呈良好的线性关系,r2=1.000,检测限小于1 nmol/mol,测定结果的相对偏差小于2%(n=6).利用大气压离子质谱仪对检测限测试结果进行了验证.采用等离子发射检测器检测氦气中微量氖气的方法,可以降低微量氖气标准物质的定值不确定度,为研制高准确度微量氖气标准物质奠定基础.

  15. Separation technique for boron and magnesium from salt lake brine and preparation of high-purity magnesium oxide%盐湖卤水硼镁分离工艺及高纯氧化镁的制备

    Institute of Scientific and Technical Information of China (English)

    于培峰; 杨喜云; 徐徽; 石西昌; 陈亚; 颜果春

    2013-01-01

    Using salt lake brine with high boron, magnesium and lithium as raw material, the boron was separated from magnesium and lithium with sulfate acid and ion exchange resin, and the magnesium was separated by precipitation with ammonia. The effects of pH value, temperature, time, resin amount, flowing rate of brine and ratio of height to diameter (H/D) of the column on boron removal were investigated under static and dynamic conditions. The optimum process conditions of boron removal are obtained. The results show that the boron removal ratio reaches 95%under the optimum process conditions. The boron concentration of brine has a significant effect on the content of boron in magnesium hydroxide. The content of boron in magnesium hydroxide increases from 0.04 mg/g to 8.82 mg/L with boron increasing from 4.54 mg/L to 1 200 mg/L. Using brine containing 4.54 mg/L boron as raw material to prepare magnesium hydroxide followed by calcination at 1 500℃for 2 h, 99.8%magnesium oxide is obtained.%  以富含硼、镁、锂的盐湖卤水为原料,采用硫酸和离子交换法联合提硼,实现硼与镁、锂分离;采用氨法沉淀镁实现镁与锂的分离.分别用静态法和动态法研究卤水pH值、吸附温度、吸附时间、树脂用量、卤水流速、交换柱高径比对硼提取率的影响,确定提硼最佳工艺条件,硼提取率达95%以上.研究卤水硼浓度对氢氧化镁中硼含量的影响.结果表明:当卤水中的硼浓度由4.54 mg/L增加到1200 mg/L时,氢氧化镁中硼含量由0.04 mg/g增加到8.82 mg/g.对硼浓度4.54 mg/L的卤水用氨法沉淀制备氢氧化镁,在1500℃下煅烧得到氧化镁,其纯度为99.8%.

  16. Bare-bones teaching-learning-based optimization.

    Science.gov (United States)

    Zou, Feng; Wang, Lei; Hei, Xinhong; Chen, Debao; Jiang, Qiaoyong; Li, Hongye

    2014-01-01

    Teaching-learning-based optimization (TLBO) algorithm which simulates the teaching-learning process of the class room is one of the recently proposed swarm intelligent (SI) algorithms. In this paper, a new TLBO variant called bare-bones teaching-learning-based optimization (BBTLBO) is presented to solve the global optimization problems. In this method, each learner of teacher phase employs an interactive learning strategy, which is the hybridization of the learning strategy of teacher phase in the standard TLBO and Gaussian sampling learning based on neighborhood search, and each learner of learner phase employs the learning strategy of learner phase in the standard TLBO or the new neighborhood search strategy. To verify the performance of our approaches, 20 benchmark functions and two real-world problems are utilized. Conducted experiments can been observed that the BBTLBO performs significantly better than, or at least comparable to, TLBO and some existing bare-bones algorithms. The results indicate that the proposed algorithm is competitive to some other optimization algorithms. PMID:25013844

  17. Bare-Bones Teaching-Learning-Based Optimization

    Directory of Open Access Journals (Sweden)

    Feng Zou

    2014-01-01

    Full Text Available Teaching-learning-based optimization (TLBO algorithm which simulates the teaching-learning process of the class room is one of the recently proposed swarm intelligent (SI algorithms. In this paper, a new TLBO variant called bare-bones teaching-learning-based optimization (BBTLBO is presented to solve the global optimization problems. In this method, each learner of teacher phase employs an interactive learning strategy, which is the hybridization of the learning strategy of teacher phase in the standard TLBO and Gaussian sampling learning based on neighborhood search, and each learner of learner phase employs the learning strategy of learner phase in the standard TLBO or the new neighborhood search strategy. To verify the performance of our approaches, 20 benchmark functions and two real-world problems are utilized. Conducted experiments can been observed that the BBTLBO performs significantly better than, or at least comparable to, TLBO and some existing bare-bones algorithms. The results indicate that the proposed algorithm is competitive to some other optimization algorithms.

  18. Iron line profiles in Suzaku spectra of bare Seyfert galaxies

    CERN Document Server

    Patrick, A R; Porquet, D; Markowitz, A G; Lobban, A P; Terashima, Y

    2010-01-01

    We methodically model the broad-band Suzaku spectra of a small sample of six 'bare' Seyfert galaxies: Ark 120, Fairall 9, MCG-02-14-009, Mrk 335, NGC 7469 and SWIFT J2127.4+5654. The analysis of bare Seyferts allows a consistent and physical modelling of AGN due to a weak amount of any intrinsic warm absorption, removing the degeneracy between the spectral curvature due to warm absorption and the red-wing of the Fe K region. Through effective modelling of the broad-band spectrum and investigating the presence of narrow neutral or ionized emission lines and reflection from distant material, we obtain an accurate and detailed description of the Fe K line region using models such as laor, kerrdisk and kerrconv. Results suggest that ionized emission lines at 6.7 keV and 6.97 keV (particularly Fe XXVI) are relatively common and the inclusion of these lines can greatly affect the parameters obtained with relativistic models i.e. spin, emissivity, inner radius of emission and inclination. Moderately broad components...

  19. Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

    Energy Technology Data Exchange (ETDEWEB)

    Mahnken, Andreas H., E-mail: mahnken@med.uni-marburg.de [University Hospital Giessen and Marburg, Philipps University of Marburg, Department of Diagnostic Radiology (Germany); Hoffman, Andras; Autschbach, Ruediger; Damberg, Anneke L. M., E-mail: anneke.damberg@rwth-aachen.de [University Hospital RWTH Aachen, Department of Thoracic, Cardiac and Vascular Surgery (Germany)

    2013-08-01

    BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach. A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.

  20. Radiolabelling, quality control and radiochemical purity assessment of the Octreotide analogue {sup 68}Ga DOTA NOC

    Energy Technology Data Exchange (ETDEWEB)

    Di Pierro, D.; Rizzello, A. [PET Radiopharmacy-Nuclear Medicine, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy); Cicoria, G. [Medical Physics, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy); Lodi, F. [PET Radiopharmacy-Nuclear Medicine, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy); Marengo, M.; Pancaldi, D. [Medical Physics, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy); Trespidi, S. [PET Radiopharmacy-Nuclear Medicine, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy); Boschi, S. [PET Radiopharmacy-Nuclear Medicine, Azienda Ospedaliero, Universitaria di Bologna, S. Orsolo-Malpighi Hospital, Via Massarenti 9, 40318 Bologna (Italy)], E-mail: stefano.boschi@aosp.bo.it

    2008-08-15

    Somatostatin receptors 1-5 are over expressed in neuroendocrine tumours (NETs). {sup 68}Ga-labelled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-Nal3-Octreotide (DOTA NOC), a recent synthesized somatostatin analogue, shows high affinity for those receptors. Herein, modifications of a commercial module for the labelling of DOTA NOC with {sup 68}Ga, as well as the assessment of time course of the radiochemical purity variation are described. The evaluation of radiochemical stability was done by two different chromatographic methods: reversed-phase radio HPLC and fast TLC analysis. Labelled compound has been found radiochemically stable within 3 h from the end of labelling (EOL) and radiochemical purity was always higher than 99%. After 73 labelling sessions the system showed great reproducibility and high radiochemical yield.