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Showing 1 to 20 of 483 for “"tungsten"”.
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Catalytic Activity of Tungsten-dioxo and Tungsten-diimido Complexes
… diol substrates exemplifying the first reported tungsten catalyzed DODH. Multiple DODH reaction mechanisms were accessible with reduction of the W-O bond achieved by oxidative C-C bond cleavage and transfer hydrogenation. The reduction of dioxo-W(VI) complexes via oxygen atom abstraction by …
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Mechanical properties of recrystallized, high purity tungsten and a tantalum-tungsten alloy
Thesis: B.S., Massachusetts Institute of Technology, Department of Metallurgy, 1961
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Trends in Tungsten Coil Atomic Spectrometry
… atomic spectrometric methods based on tungsten coil atomizers is a consequence of a world wide increasing demand for fast, inexpensive, sensitive, and portable analytical methods for trace analysis. In this work, tungsten coil atomic absorption spectrometry (WCAAS) and tungsten coil …
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Critical magnetic fields of superconducting tungsten
… critical field curve of a superconducting tungsten specimen with resistivity ratio 7,500 has been measured as a function of temperature down to 3 m K (1 m K - 10-3 oK). From the raw data the critical field H0 at T = 0 is found to be 1.14·1 ± .007 G, and the zero field transition temperature …
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Tungsten Coil Electrothermal Vaporization for Atomic Spectroscopy
Electrothermal vaporization has served as an alternative sample introduction method in atomic spectroscopy for some time. Typically, electrothermal vaporizers made of graphite, but these devices do not lend well to mass production, are expensive, and require large power supplies for operation. In …
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Thermionic emission from a recrystallized tungsten filament
… thermionic emission parameters of a tungsten single crystal with {110} zone 8° to 10° off filament axis. Pecrystallization of the filament was achieved by the Robinson (27) method of heating treatment. The average <}>* and A* were found to be 4.485 ± 0.055 volts and 49 ± 16 amp per …
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Quantum Dots In Two-Dimensional Tungsten Diselenide
… two-dimensional transition metal dichalcogenide tungsten diselenide (WSe_2) as a means to evaluate the valley degree of freedom as a potential qubit and ambipolar tungsten diselenide monolayers as single photon sources. Gate-defined quantum dots in monolayer and bilayer WSe_2 were fabricated and …
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Electron Scattering From a Tungsten (100) Crystal
Made available in DSpace on 2015-05-12T21:41:56Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 7020956.PDF: 4540997 bytes, checksum: 66cdc23b641b1582b450907003df0229 (MD5) Previous issue date: 1970
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Non-Isothermal Chemisorption of Hydrogen on Tungsten
Made available in DSpace on 2014-12-09T17:13:31Z (GMT). No. of bitstreams: 1 6408388.pdf: 1992982 bytes, checksum: ea3ce3be5f8de40d17b600168d574274 (MD5) Previous issue date: 1964
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Residual stress in nanocrystalline nickel tungsten electrodeposits
Characterizing the residual stress of thick nanocrystalline electrodeposits poses several unique challenges due to their fine grain structure, thickness distribution, and matte surface. We employ a three-dimensional profilometry-based approach that addresses each of these complicating factors and …
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Tungsten carbide-cobalt by Three Dimensional Printing
… parts [Sachs, et al, 1990]. Green (not sintered) tungsten carbide-cobalt parts must have a density greater than 50% of the theoretical density, 14.9 g/cc, for proper sintering and post-processing. Two approaches were assessed for feasibility and robustness: printing slurry into tungsten …
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Synthesis, characterization and reactivity of tungsten oxynitride
High surface area tungsten oxynitride samples have been prepared by the temperature programmed reaction (TPR) of W0₃ with NH₃. All samples were characterized by X-ray diffraction (XRD), nitrogen physisorption, and CO chemisorption. In addition, some sample compositions were determined by elemental …
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The effects of thermal history and composition on the thermodynamic behaviour of helium in tungsten and tungsten-based alloys
Nuclear fusion power is the promise of clean energy generation to meet the demands of the new century. However, containing a plasma with a core temperature ten times hotter than that of the sun is no easy task. The confinement vessel must be constructed from resilient materials that can withstand …
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The effects of thermal history and composition on the thermodynamic behaviour of helium in tungsten and tungsten-based alloys
Nuclear fusion power is the promise of clean energy generation to meet the demands of the new century. However, containing a plasma with a core temperature ten times hotter than that of the sun is no easy task. The confinement vessel must be constructed from resilient materials that can withstand …
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Surface reactions of boron with clean tungsten substrates
… boron will increase the work function of a clean tungsten substrate at coverages between 0 and 1 monolayer. This is the first time that a single model has been shown to predict both positive and negative work function changes for different adsorbates. The reactions of chemically, vapor-deposited …
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Diffusion and Evaporation of Nitrogen on Tungsten (100)
… of nitrogen chemisorbed on the (100) plane of tungsten has been examined using Auger spectroscopy. The initial localized deposit required for diffusion measurements in a concentration gradient is created by a highly collimated molecular beam. The sample, under computer control, is moved across …
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Some Organometallic Chemistry of Tungsten-Triosmium Cluster Compounds
… the synthesis, structure, and reactivity of new tungsten-triosmium (WOs(,3)) cluster compounds. The presence of a tungsten atom in the cluster framework imparts a considerably different reactivity pattern than that observed in triosmium chemistry.
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Desorption and Surface Diffusion: Nitrogen on Tungsten (110)
Made available in DSpace on 2014-12-14T16:00:35Z (GMT). No. of bitstreams: 1 7804116.pdf: 4792915 bytes, checksum: ba5e3c05ed584b197539c4094b36dc5a (MD5) Previous issue date: 1977
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High-Energy Neutron Transport Through Tungsten and Iron
Made available in DSpace on 2014-12-14T06:26:08Z (GMT). No. of bitstreams: 1 8004188.pdf: 5825708 bytes, checksum: 7e7b6496b41591a9809501a51685b4d6 (MD5) Previous issue date: 1979
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