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  Partner: UNT Libraries
 Department: Department of Chemistry
 Collection: UNT Theses and Dissertations
Free Radical Induced Oxidation, Reduction and Metallization of NiSi and Ni(Pt)Si Surfaces

Free Radical Induced Oxidation, Reduction and Metallization of NiSi and Ni(Pt)Si Surfaces

Date: August 2010
Creator: Manandhar, Sudha
Description: NiSi and Ni(Pt)Si, and of the effects of dissociated ammonia on oxide reduction was carried out under controlled ultrahigh vacuum (UHV) conditions. X-ray photoelectron spectroscopy (XPS) has been used to characterize the evolution of surface composition. Vicinal surfaces on NiSi and Ni(Pt)Si were formed in UHV by a combination of Ar+ sputtering and thermal annealing. Oxidation of these surfaces in the presence of either O+O2 or pure O2 at room temperature results in the initial formation of a SiO2 layer ~ 7 Å thick. Subsequent exposure to O2 yields no further oxidation. Continued exposure to O+O2, however, results in rapid silicon consumption and, at higher exposures, the kinetically-driven oxidation of the transition metal(s), with oxides >35Ǻ thick formed on all samples, without passivation. The addition of Pt retards but does not eliminate oxide growth or Ni oxidation. At higher exposures, in Ni(Pt)Si surface the kinetically-limited oxidation of Pt results in Pt silicate formation. Substrate dopant type has almost no effect on oxidation rate. Reduction of the silicon oxide/metal silicate is carried out by reacting with dissociated NH3 at room temperature. The reduction from dissociated ammonia (NHx+H) on silicon oxide/ metal silicate layer shows selective reduction of the metal oxide/silicate layer, ...
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Effects of Using Logic and Spatial Cybergames to Improve Student Success Rates in Lower-Division Chemistry Courses

Effects of Using Logic and Spatial Cybergames to Improve Student Success Rates in Lower-Division Chemistry Courses

Date: May 2011
Creator: Manrique, Carissa Janice
Description: A study was conducted to investigate the relationships between cybergaming treatment groups and the control group (N = 99: ncontrol = 8; nlogic = 29; nspatial = 30; ncombination = 32) with success in the organic chemistry I course as measured by achievement over a 10-week period. The treatment groups included logic training, spatial training, and combination logic-spatial training. Students' ability was measured by pre/post exams using the Group Assessment of Logical Thinking (GALT) to measure logic ability, Purdue Visualizations of Rotations (ROT) test to measure spatial skills, and the General-Organic-Biochemistry (GOB) Exam to measure content attainment. Finally, students' responses about participation in this experience were evaluated using open- and closed-ended questions on a self-developed survey. A second study was conducted to evaluate the relationship between the cybergaming treatment and control groups (N = 88: nexperimental = 27; ncontrol = 61) with success in the general chemistry I course as measured by achievement and final course averages and grades. The cybergaming treatment group underwent intensive combination logic-spatial training for 10 weeks. Students' progress was measured using three pre/post instruments: Group Assessment of Logical Thinking (GALT) measured logic ability, Purdue Visualizations of Rotations (ROT) Test measured spatial skills, and the California ...
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Selective Lipid Absorption

Selective Lipid Absorption

Date: January 1960
Creator: Marcia, John Albion
Description: An experiment was designed to study in the same animal any preferential absorption of a free fatty acid in the presence of a triglyceride of the same fatty acid. Rats were administered a mixture of free fatty acid and its triglyceride labeled with carbon-13 and carbon-14 respectively. Each isotope in the fed lipid and in the lipid recovered from the gastrointestinal tract was measured. The isotope effect, if any, was studied by administering a mixture of palmitic acid-1-C13 and palmitic acid-1-C14.
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The Synthesis of Certain Alkyl Alpha-(2-Dialkylam Inoalkoxy)Phenylacetates

The Synthesis of Certain Alkyl Alpha-(2-Dialkylam Inoalkoxy)Phenylacetates

Date: 1947
Creator: Mark, Roscoe Dewey
Description: This thesis describes the procedures used in preparation of the derivatives of certain alkyl phenylacetates and the necessary intermediate compounds. Compounds resembling the structure of Benadryl were prepared in this study in the hope that at least one might prove to be of value in the fight against allergy.
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Metallization and Modification of Low-k Dielectric Materials

Metallization and Modification of Low-k Dielectric Materials

Date: December 2008
Creator: Martini, David M.
Description: Aluminum was deposited onto both Teflon AF and Parylene AF surfaces by chemical vapor deposition of trimethylaluminum. This work shows that similar thin film (100 Angstroms) aluminum oxide adlayers form on both polymers at the low temperature dosing conditions used in the studies. Upon anneal to room temperature and above, defluorination of the polymer surfaces increased and resulted in fluorinated aluminum oxide adlayers; the adlayers were thermally stable to the highest temperatures tested (600 K). Angle-resolved spectra showed higher levels of fluorination toward the polymer/adlayer interface region. Copper films were also deposited at low temperature onto Teflon AF using a copper hexafluoroacetylacetonate-cyclooctadiene precursor. Annealing up to 600 K resulted in the loss of precursor ligands and a shift to metallic copper. As with aluminum adlayers, some polymer defluorination and resulting metal (copper) fluoride was detected. Parylene AF and polystyrene films surfaces were modified by directly dosing with water vapor passed across a hot tungsten filament. Oxygen incorporation into polystyrene occurred exclusively at aromatic carbon sites, whereas oxygen incorporation into parylene occurred in both aromatic and aliphatic sites. Oxygen x-ray photoelectron spectra of the modified polymers were comparable, indicating that similar reactions occurred. The surface oxygenation of parylene allowed enhanced reactivity ...
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The Synthesis of 5-Hetero-Substituted Dihydro-4,6(1H,5H)-Pyrimidinediones

The Synthesis of 5-Hetero-Substituted Dihydro-4,6(1H,5H)-Pyrimidinediones

Date: January 1959
Creator: Matthews, Don Morris
Description: This thesis describes the attempt to synthesize some 5-hetero-substituted dihydro-4,6(1H,5H)-pyrimidinediones as possible anticonvulsants.
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Thiophene Analogs of DDT; O-Alkylhydorxylamine Hydrochorides; Dialkylaminoalkyl Esters of Phenoxyacetic Acid

Thiophene Analogs of DDT; O-Alkylhydorxylamine Hydrochorides; Dialkylaminoalkyl Esters of Phenoxyacetic Acid

Date: 1947
Creator: Mattison, Marjorie Bess
Description: This thesis describes three separate and unrelated chemical experiments. The first investigates analogs for the compound DDT. The second investigates the properties of O-substituted hydroxylamines. The third investigates the action of slight changes to the structure of an antihistaminic agent.
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Synthesis of Selected 2-imidazolines

Synthesis of Selected 2-imidazolines

Date: June 1966
Creator: Maurer, Larry Eugene
Description: Since Djerassi and Scholz found that 2-(aryloxy-methyl)imidazolines and their hydrochloride salts exhibit vasoconstrictive properties, the 1,2-(I) 1,3-(II) and 1,4-bis-(2-imidazolinylmethoxy) benzene (III) analogs (Fig. 1, p.2) were chosen for synthesis in order to test them for their effective vasoconstrictive characteristics and for whatever other physiological properties they might exhibit.
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An Analysis of Elementary Science Material Included in Certain Courses of Study and Text Books

An Analysis of Elementary Science Material Included in Certain Courses of Study and Text Books

Date: August 1937
Creator: Maurice, Katherine
Description: The purpose of this study is to assess the contribution of elementary science to the curriculum. The finding of the investigation summarized in table form.
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Experimental and Theoretical Study of Electronic Transitions in Phosphorus, Phosphoryl, and Thiophosphoryl Trichlorofluorides

Experimental and Theoretical Study of Electronic Transitions in Phosphorus, Phosphoryl, and Thiophosphoryl Trichlorofluorides

Date: May 1973
Creator: McAdams, Mary Jane
Description: This thesis is an investigation of the vacuum uv spectra of the phosphorus, phosphoryl, and thiophosphoryl trichlorofluorides in the region 1250 to 3000A. Assignments for absorption bands are made utilizing results from photoelectron spectra and ab initio calculations, oscillator strengths for absorption bands, and CNDO/2 molecular orbital calculations. Results from CNDO/2 calculations are compared with theoretical calculations, and experimental data are discussed with regard to the bonding in the compounds.
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