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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Synthesis and adsorption properties of molybdenum(IV) sulfide and tungsten(IV) sulfide nanostructures with curved atomic layers / Title on signature form: Synthesis and adsorption properties of molybdenum (IV) sulfide and tungsten (IV) sulfide with curved atomic layers

Combs, Ryan J. 25 January 2012 (has links)
Access to abstract permanently restricted to Ball State community only / Construction of experimental setup -- Synthesis of MoS₂ and WS₂ fullerene like structures -- Synthesis of MoS₂ and WS₂ nanotube like structures -- Infrared spectroscopy of acetonitrile adsorption on synthesized MoS₂ materials. / Access to thesis permanently restricted to Ball State community only / Department of Chemistry
22

A comparative study of the complex formation of molybdenum(VI) and tungsten(VI) with ligands derived from carboxlic acids

Rohwer, E. A. (Elisabeth Anna) 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Please refer to fulltext for abstract / AFRIKAANSE OPSOMMING: Sien asb volteks vir opsomming
23

Biscyclopentadienyl complexes of molybdenum (IV) and Tungsten (IV) containing polysulfane ligands

Marmolejo Rivas, Gabriela. January 1986 (has links)
No description available.
24

Tungsten carbides as potential alternative direct methanol fuel cell anode electrocatalysts

Zellner, Michael. January 2006 (has links)
Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Jingguang G. Chen, Dept. of Chemical Engineering. Includes bibliographical references.
25

Biscyclopentadienyl complexes of molybdenum (IV) and Tungsten (IV) containing polysulfane ligands

Marmolejo Rivas, Gabriela. January 1986 (has links)
No description available.
26

Synthesis and photocatalytic activity of the MoS2 and WS2 nanoparticles in degradation of organic compounds

James, Derak J. January 2009 (has links)
Nanoparticles of MoS2 and WS2 were synthesized by decomposing the appropriate metal hexacarbonyl in the presence of sulfur dissolved in decalin at 140°C. A significant fraction of the nanoparticles was ≤ 15 nm in diameter as verified by Transmission Electron Microscopy. The process was repeated in the presence of silica and then titania to produce supported metal sulfides. The unsupported nanoparticles were found to exhibit a size-dependent shift in their threshold UV-visible absorption due to quantum confinement. Photocatalytic properties of each sulfide from synthesis in decalin were explored by using each as a catalyst in the photodegradation of methylene blue by visible light. These sulfides were also used to catalyze the photodegradation of acetone. Unsupported MoS2 and WS2 nanoparticles catalyzed the photodegradation of acetone under visible light of ≥ 400 nm wavelength. This is the first study reporting the photocatalytic properties of the unsupported WS2 nanoparticles. Photodegradation of methylene blue under ≥ 435 nm irradiation was detected using unsupported WS2 but not unsupported MoS2, likely because activity was masked by the likely photobleaching of the dye. When deposited on silica or titania, the nanosized MoS2 and WS2 could be uniformly distributed in aqueous solutions to maximize the photocatalytic efficiency. Correcting the absorbance measurements for light scattering by solids proved to be beneficial for extracting kinetic information. Both silica deposited sulfides were found to significantly increase the rate of methylene blue photodegradation, and deposited WS2 increased this rate significantly more than deposited MoS2. Similarly, both titania deposited sulfides significantly increased the rate of methylene blue photodegradation, and the deposited WS2 increased this rate significantly more than the deposited MoS2 / Synthesis of the sulfide photocatalysts -- Characterization of synthesized nanoparticles -- Photocatalytic degradation tests : setup and protocols -- Photocatalytic degradation tests : results. / Department of Chemistry
27

Bereiding en reaktiwiteit van asolinildeen- en divinielkarbeenkomplekse van Cr, Mo en W

Stander, Yolanda 30 August 2012 (has links)
M.Sc. / This study comprises the preparation and characterisation of new azolinylidene- and divinylcarbene complexes of chromium, molybdenum and tungsten, from 1- phenylpyrawle, 1-methylimidazole and 4,4-dimethyl-2,2-thienyloxazoline precursors. The reaction of 1-phenylpyrazolyllithium with (C0) 6M (M Cr, Mo or W) yields after alkylation with CH3S03CF3 in THE the two products (C0)5M[C(OCH3X(ONPhNCHC(H)] and (C0)5M[C(0{CH2}40C113)(aNPhNCH6H)]. A 'H NMR study indicates the existence of two isomers for each of the two tungsten CO'cli•lexes. 1-Methylimidazolyllithiura reacts with (CO)6M (M = Cr, Mo or W) to give the carbene complexes (C0)5MK'N(CH3)CHCH14(C I i 3)] after alkylation with CH3S03CF3, and the imine complexes (C0)5MOCHN(CH3)CH6H] after protonation with SO3CF3. Reaction of 1-methylimidazolyllithium with the anionic salt (C0)5 Cl = Cr or W), followed by alkylation with CH3S03CF3 affords both the mono- and bis(carbene) complexes, (CO)5M[CN(CH3)CHCHN(CH3)] and (C0)41v1[6N(CH3)CHCIRA(CH3)]2. The complex (C0)5W[C(0 {CH2 } 40C113)(t‘NPhNaldH)] reacts with phenylethynthiolate to furnish an anionic organometallic synthon that can either be alkylated or protonated. Protonation leads to two isomeric forms of the metal-coordinated thioaldehyde, (C0)5W4—SHC(Ph)=C(OCH3)(oNPhNCHell), whilst alkylation with various electrophilic reagents produces the metal coordinated dithio-esther (C0)5 W4--S=C [ SCH3] [C(Ph)=C(OCH3)(tNPhNaldH)]. The neutral divinylcarbene complexes (C0)5Cr{cC(a0CH2CMe2N)SC CH} (a) and (C0)5W{cC(COCH2CMe214)SCH9H} (19) are prepared by reaction of (C0)5MCr with the 3-lithiated thienyloxazoline, followed by alkylation with CH3S03CF3 . These complexes are the first examples of coordinated 'divinylcarbenes utilizing the group 6 transition metals, where the carbene carbon shows carbene character. They are also in another sense unique since the nucleopbutlic heteroatom where alkylation occurs, is situated outside the coordinated ring-system, and, therefore, more than two bonds removed fro the carbene carbon atom.
28

Synthesis and reactivity of multiply bonded tungsten dimers

Sturgeoff, Lynda Gail. January 1982 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 1982 / Includes bibliographical references. / by Lynda Gail Sturgeoff. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Chemistry
29

Synthesis and oxo-transfer properties of high-valent dioxo-tungsten and -molybdenum complexes with N, O, and S donor ligands. / CUHK electronic theses & dissertations collection

January 1999 (has links)
by Yee-Lok Wong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
30

Design and fabrication of sub-millimeter scale gas bearings with tungsten-containing diamond like carbon coatings

Kim, Daejong 28 August 2008 (has links)
Not available / text

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