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Synthesis and X-ray Diffraction Structures of 2-(2-thienylidene)-4,5-bis-(diphenylphosphino)-4-cyclopenten-1,3-dione and fac-BrRe(CO)3[2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione]

Description: Treatment of 4,5 bis-(diphenylphosphino)-cyclopenten-1,3 dione with thiophene carboxyaldehyde in dichloromethane, in the presence of molecular sieves results in a new heterocyclic compound, 2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (ligand), with a high yield. This product was characterized by using both IR and NMR spectroscopic techniques and the solid-state structure of the ligand was determined using X-ray crystallography. When the ligand was treated with the solv… more
Date: December 2005
Creator: Pingali, Aparna
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Microwave-Assisted Synthesis, Characterization, and Photophysical Properties of New Rhenium(I) Pyrazolyl-Triazine Complexes

Description: The reaction of the chelating ligand 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl]-N,N-diethyl-benzenamine, L, with pentacarbonylchlororhenium by conventional heating method produces the complexes fac-[ReL(CO)3Cl2] and fac-[Re2L(CO)6Cl2] in a period of 48 hours. The use of microwaves as the source of heat and the increase in the equivalents of one of the reactants leads to a more selective reaction and also decreases the reaction time to 1 hour. After proper purification, the pho… more
Date: May 2010
Creator: Salazar Garza, Gustavo Adolfo
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Synthetic and Structural Chemistry of Ligand-substituted Triosmium Clusters and a Rhenium(i) Complex

Description: The reaction of 2-[(diphenylphosphino)methyl]-6-methylpyridine (PN) with Os3(CO)12-n(MeCN)n [where n = 0 (1), 1 (2), 2 (3)] has been investigated. Os3(CO)12 reacts with PN in the presence of Me3NO to afford the clusters Os3(CO)11(1-PN) (4) and 1,2-Os3(CO)10(1-PN)2 (5). X-ray diffraction analyses confirm the equatorial coordination of the phosphine(s) in 4 and 5, with the two phosphines in the latter cluster exhibiting a 1,2-trans orientation about the Os-Os vector that contains the two ligand… more
Date: August 2013
Creator: Lin, Chen-Hao
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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X-ray diffraction studies using diamond coated rhenium gasket to megabar pressures

Description: X-ray diffraction studies at megabar pressures are limited by the sample thickness between the diamond anvils. High strength gaskets are desirable to improve the quality of x-ray diffraction data. We present a technique which employs a microwave plasma chemical vapor deposited diamond layer on one side of a rhenium gasket. As a test case, we show energy dispersive x-ray diffraction data on rare earth metal neodymium to 153 GPa using a synchrotron source. The increased sample thickness results i… more
Date: September 30, 1999
Creator: Akella, J; Catledge, S A; Chesnut, G N; Prokop, H; Vohra, Y K & Weir, S T
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ligand intermediates in metal-catalyzed reactions; Annual technical report, August 1, 1992--August 1, 1993

Description: Achievements are reported for the following 4 areas: {pi}/{sigma} equillibria in aldehyde and ketone complexes; thermodynamic ligand binding affinities ({alpha},{beta} unsaturated organic carbonyl compounds); (a new form of coordinated carbon) an unsupported C{sub 3} chain that spans two different transition metals; and (a new form of coordinated carbon) an C{sub 3} chain that is anchored by a metal on each end and spanned by a third.
Date: August 10, 1993
Creator: Gladysz, J.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Technology development for cobalt F-T catalysts. Quarterly technical progress report number 10, January 1--March 31, 1995

Description: The goal of this project is the development of a commercially-viable, cobalt-based Fischer-Tropsch (F-T) catalyst for use in a slurry bubble column reactor. The major objectives of this work are (1) to develop a cobalt-based F-T catalyst with low (< 5%) methane selectivity, (2) to develop a cobalt-based F-T catalyst with water-gas shift activity, and (3) to combine both these improvements into one catalyst. The project consists of five major tasks: catalyst development; catalyst testing; cataly… more
Date: June 28, 1995
Creator: Singleton, Alan H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Anisotropy of the sublattice magnetization and magnetoresistance in Co/Re superlattices on Al{sub 2}O(1120).

Description: [Co(20 {angstrom})/Re(6{angstrom})]{sub 20} superlattices were grown on a (11{bar 2}0) surface of a Al{sub 2}O{sub 3} single crystal, with the [0001] direction of their hcp structure in the plane of the film. The Co layers were found to be antiferromagnetically coupled (AF), with a saturating field of 6 kOe. Polarized neutron reflectivityy was used to determine the direction of the sublattice magnetization. In zero applied field, the AF moments are aligned along the Co [0001] axis. In a magneti… more
Date: September 29, 1998
Creator: Charloton, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Organic transformations catalyzed by methylrhenium trioxide

Description: Methylrhenium trioxide (MTO), CH{sub 3}ReO{sub 3}, was first prepared in 1979. MTO forms stable or unstable adducts with electron-rich ligands, such as amines (quinuclidine, 1,4-diazabicyclo-octane, pyridine, aniline, 2,2{prime}-bipyridine), alkynes, olefins, 1,2-diols, catechols, hydrogen peroxide, water, thiophenols, 1,2-dithiols, triphenylphosphine, 2-aminophenols, 2-aminothiophenols, 8-hydroxyquinoline and halides (Cl-, Br-, I-). After coordination, different further reactions will occur fo… more
Date: November 1, 1995
Creator: Zhu, Z.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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High Temperature Materials Technology Research for Advanced Thermionic Systems. Quarterly Progress Report, March 1, 1995--June 30, 1995

Description: The concept of shift factor was used successfully to develop a model which described the role of solid solution atoms in dispersion strengthened tungsten alloys. This shift factor separates the solid solution strengthening effect of Re in the creep of W-Re-HfC materials. The creep of the alloys is expressed by the modified Lagneborg`s creep model in the following form: {dot {var_epsilon}} = A`(b/G{sup 3}kT)D{sub L}exp({minus} 580000eC{sup 1/2}/T)({sigma} {minus}{sigma}{sub p}){sup 4} (1955 K{le… more
Date: December 1, 1995
Creator: Zee, R. H. & Rose, M. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Volatility literature of chlorine, iodine, cesium, strontium, technetium, and rhenium; technetium and rhenium volatility testing

Description: A literature review pertaining to the volatilization of Sr, Cs, Tc (and its surrogate Re), Cl, I and other related species during the vitrification of Hanford Low Level Waste (LLW) streams has been performed and the relevant information summarized. For many of these species, the chemistry which occurs in solution prior to the waste stream entering the melter is important in dictating their loss at higher temperatures. In addition, the interactive effects between the species being lost was found… more
Date: March 1, 1996
Creator: Langowski, M. H.; Darab, J. G. & Smith, P. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Predicting ion charge state distributions of vacuum arc plasmas

Description: Multiply charged ions are present in vacuum arc plasmas. The ions are produced at cathode spots, and their charge state distributions (CSDs) depend on the cathode material but only little on the arc current or other parameters as long as the current is relatively low and the anode is not actively involved in the plasma production. There are experimental data of ion CSDs available in the literature for 50 different cathode materials. The CSDs can be calculated based on the assumption that thermo… more
Date: April 1, 1996
Creator: Anders, A. & Schulke, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Proton radioactivity studies at the FMA

Description: A double sided silicon strip (DSSD) setup is installed at the Argonne National Laboratory recoil separator FMA. Ground state proton emitters {sup 146,147}Tm, {sup 160}Re, {sup 156}Ta, {sup 150,151}Lu were produced in a series of test experiments. Improved T{sub 1/2} values were obtained for {sup 147}Tm, {sup 160}Re, and {sup 156}Ta. Improved alpha T{sub 1/2} value of (13.2 {plus_minus} 1.1) ms was obtained for {sup 161}Re. In a search of new proton radioactivities a (5 {plus_minus} 2)% proton d… more
Date: December 31, 1995
Creator: Penttila, H.; Davids, C.N. & Woods, P.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stainless steel-zirconium alloy waste forms

Description: An electrometallurgical treatment process has been developed by Argonne National Laboratory to convert various types of spent nuclear fuels into stable storage forms and waste forms for repository disposal. The first application of this process will be to treat spent fuel alloys from the Experimental Breeder Reactor-II. Three distinct product streams emanate from the electrorefining process: (1) refined uranium; (2) fission products and actinides extracted from the electrolyte salt that are pro… more
Date: July 1996
Creator: McDeavitt, S. M.; Abraham, D. P.; Keiser, D. D. Jr. & Park, J. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Separation of Technetium From Nuclear Waste Stream Simulants. Final Report

Description: The authors evaluated several calorimetric assays for ReO{sub 4}{sup {minus}}, and discovered that all were flawed. They evaluated atomic absorption spectroscopy as a technique to determine sub-millimolar concentrations of ReO{sub 4}{sup {minus}}, and discovered that it is not sensitive enough for their use. However, they discovered that ICP-AES can be used to determine concentrations of ReO{sub 4}{sup {minus}} down to 0.25 ppm. They next determined that ReO{sub 4}{sup {minus}} can be quickly e… more
Date: September 30, 1994
Creator: Strauss, S.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Nuclear medicine program progress report for quarter ending September 30, 1995

Description: In this report, we describe the results for study of the production of lutetium-177 ({sup 177}Lu) in the High Flux Isotope Reactor (HFIR). Two pathways for production of {sup 177}Lu were studied which involved both direct neutron capture on enriched {sup 176}Lu, {sup 176}Lu (n,{gamma}){sup 177}Lu, reaction and by decay of ytterbium-177 ({sup 177}Yb) produced by the {sup 176}Yb(n,{gamma}){sup 177}Yb ({beta}{sup {minus}} {sup {yields}}) reaction. Although the direct route is more straight forward… more
Date: December 31, 1995
Creator: Knapp, F. F., Jr.; Ambrose, K. R.; Beets, A. L.; Luo, H.; McPherson, D. W. & Mirzadeh, S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Molecular-level assemblies on metal oxide surfaces

Description: This is the final report of a one-year, Laboratory-Directed Research and Development project at the Los Alamos National Laboratory (LANL). The objective of this project was to explore molecular-level assemblies based on polypyridyl transition metal complexes attached to metal oxide surfaces to provide the basis for applications such as energy conversion and electricity generation, photoremediation of hazardous waste, chemical sensors, and optical storage and photorefractive devices for communic… more
Date: July 1, 1996
Creator: Schoonover, Jon R.; Bignozzi, Carlo & Meyer, Thomas
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of hydrogen on the dynamics of the Mo{sub 0.95}Re{sub 0.05}(ll0) surface

Description: The effect of adsorbed H on the Mo{sub 0.95}Re{sub 0.05}(110) surface has been investigated. Results obtained from low-energy electron diffraction, high-resolution electron energy loss spectroscopy (HREELS) and angle-resolved ultra-violet photoemission spectroscopy are presented. A (2{times}2) LEED pattern is observed for H coverages around {Theta} {approximately} 0.6 ML and is attributed to reconstruction of the substrate. At higher coverages, a (1{times}1) pattern is observed. Two peaks are o… more
Date: August 1995
Creator: Okada, M.; Plummer, E. W.; Baddorf, A. P. & Zehner, D. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Nuclear medicine program progress report for quarter ending September 30, 1996

Description: The reactor production yields of tungsten-188 produced by neutron capture by enriched tungsten-186 in the HFIR and other reactors are nearly an order of magnitude lower than expected by calculation using established cross section values. Since neutron capture of tungsten-188 may be the major factor which significantly reduces the observed yields of tungsten-188, the authors have evaluated the possible burn-up cross section of the tungsten-188 product. Tungsten-189 was produced by irradiating a … more
Date: January 1, 1997
Creator: Knapp, F. F., Jr.; Ambrose, K. R.; Beets, A. L.; Boll, R.; Luo, H.; McPherson, D. W. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Near net shape processing for solar thermal propulsion hardware using directed light fabrication

Description: Directed light fabrication (DLF) is a direct metal deposition process that fuses gas delivered powder, in the focal zone of a high powered laser beam to form fully fused near net shaped components. The near net shape processing of rhenium, tungsten, iridium and other high temperature materials may offer significant cost savings compared with conventional processing. This paper describes a 3D parametric solid model, integrated with a manufacturing model, and creating a control field which runs o… more
Date: December 1, 1998
Creator: Milewski, J. O.; Fonseca, J. C. & Lewis, G. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Isotope tracer studies of diffusion in silicates and of geological transport processes in aqueous systems using actinide elements

Description: This research program has moved ahead with success in several areas. The isotopic composition of osmium in seawater and in some rivers was directly determined for the first time. The concentration of osmium was first estimated in both seawater and rivers. A major effort was directed toward the transport of the U,Th series nuclides in a watershed in Sweden. A serious effort was directed at developing a transport model for the U,Th series nuclides in aquifers. A detailed study of {sup 238}U-{sup … more
Date: February 1, 1999
Creator: Wasserburg, G. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Atom transfer and rearrangement reactions catalyzed by methyltrioxorhenium, MTO

Description: Methyltrioxorhenium (MTO) catalyzes the desulfurization of thiiranes by triphenylphosphine. Enormous enhancement in rate is observed when the catalyst is pretreated with hydrogen sulfide prior to the reaction. Using 2-mercaptomethylthiophenol as a ligand, the author synthesized several model complexes to study the mechanism of this reaction. With suitable model systems, they were able to show that the active catalyst is a Re(V) species. The reactions are highly stereospecific and very tolerant … more
Date: May 10, 1999
Creator: Jacob, J.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Oxidation Behavior of Cr-Cr{Sub 2}Nb Alloys

Description: Oxidation of hypoeutectic Cr-Cr{sub 2}Nb alloys containing 6 and 12% Nb at 950 C resulted in formation of a multiproduct scale consisting of a continuous Cr{sub 2}O{sub 3} outer layer and an inner region of discrete CrNbO{sub 4} products interspersed with Cr{sub 2}O{sub 3}. Overall oxidation behavior resembled that of Cr as reactions with the Cr-rich phase tended to dominate. Oxidation resistance, in terms of reaction kinetics and scale adherence, increased with increasing volume fraction of th… more
Date: December 31, 1996
Creator: Tortorelli, P. F. & Pint, B. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Photoinduced energy transfer in transition metal complex oligomers

Description: The work done over the past three years has been directed toward the preparation, characterization and photophysical examination of mono- and bimetallic diimine complexes. The work is part of a broader project directed toward the development of stable, efficient, light harvesting arrays of transition metal complex chromophores. One focus has been the synthesis of rigid bis-bidentate and bis-tridentate bridging ligands. The authors have managed to make the ligand bphb in multigram quantities fro… more
Date: June 1, 1997
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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