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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.
41

Sonoelectroanalysis : theory and experiment

Ball, Jonathan C. January 2000 (has links)
This thesis reports the development of sonoelectrochemistry as a technique for sample analysis. Complementary modelling gives an insight into the mass transport and electrode reaction mechanisms. Separate studies were conducted as follows: - Initially an copper(II) acetate buffer system was used as its speciation can be determined. In order to establish under which conditions analysis could be conducted the effect of speciation was examined. These were applied to the Anodic Stripping Voltammetry (ASV) determination of copper in the acetate solution and to facilitate the use of a traditionally inhospitable electrochemical medium: real ale with minimal pre-treatment. Both gave detection limits of the range (1-100) μg L<sup>-1</sup> and in quantitative agreement with Atomic Absorption Spectroscopy. - The effect of acoustic streaming under mild insonation was studied by modelling Square Wave Voltammetry (SWV) of ASV and was found, when compared to experiment, to be the dominating factor. When the latter is strongly present two distinct mass.transport regimes were identified. Studies of chemical and electrochemical processes suggested that the acoustic streaming model fails under more extreme conditions. - SWV voltammetry was modelled for reversible electrochemical reactions leading to a refinement of existing analytical theory and the ASV modelling extended to account for surface morphology and finite electrode kinetics. Droplets on an electrode surface subjected to a potential sweep give rise to voltammetric traces attributed to charge insertion. Three mechanisms for this are proposed: (i) charge injection at the droplets surface, (ii) charge injection at the three phase boundary and (iii) the droplet is saturated with counter ions and electron transfer occurs at the electrode surface. These are solved numerically and incorporate Regular Solution Theory to account for non-ideal interactions. Comparing with experimental data an approximate model identified the processes occurring for small droplets. A Marangoni-type convection is suggested for larger droplets.
42

The electro deposition of lead in sugar and acetate solutions

Kaplan, Abe Lew. January 1915 (has links) (PDF)
Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1915. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed April 24, 2009) Includes bibliographical references (p. 15).
43

Design and testing of a computer-controlled square wave voltammetry instrument /

Wengenack, Nancy L. January 1987 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1987. / Typescript. Includes bibliographical references (leaves 107-108).
44

Neutralization reactions of phosphoric acid and of calcium acid phosphate

Parsons, Lemial Deloss, January 1900 (has links)
Thesis (Ph. D.)--Vanderbilt University, 1933. / Bibliography: p. 48-49.
45

Chemically modified electrodes with inorganic films of noble metal complexes and metal oxides : preparation, characterization and applications /

Han, Qi. January 2002 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.
46

The composition of anodic lead dioxide and its use in the quantitative determination of small amounts of lead

Day, Thomas Gordon, January 1900 (has links)
Thesis (Ph. D.)--University of Missouri, 1935. / Vita. By T.G. Day and W.T. Schrenk. Published also as part 2 of "The quantitative determination of lead by the electrolytic deposition of lead dioxide ... By Thomas Gordon Day, Phillip Hall Delano and W.T. Schrenk." Rolla, Mo., 1935. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 62-68.
47

Synthesis, photophysical properties and applications of aggregation-induced emission materials based on cyanostilbene moiety

Dong, Yujie 05 September 2016 (has links)
The concept of "aggregation-induced emission" (AIE) effect has induced a great deal of attention these days. Now, exploration of new AIE-active molecular system and multiple high technique applications for AIE materials are the two research hotspots. Cyanostilbene, as a classical structural unit in photoelectric functional materials, also exhibited this unique luminescence behavior. The research background was illustrated in Chapter 1, which mainly introduced the development of this subject. In this project, Chapter 2 and Chapter 3 presented two classes of functionalized AIE-active molecules based on cyanostilbene moiety, and their applications were investigated, while Chapter 4 demonstrated a series of donor-acceptor (D-A) molecules with highly emissive unit, and their photophysical properties were studied.;In Chapter 2, four different donor-substituted cyanostilbene-based dipyrrins were synthesized and characterized. The investigation of photophysical properties confirms that these molecules are AIE-active, which should be attributed to the cyanostilbene moiety. The introduction of different donor groups showed little impact on their luminescence. Furthermore, the emission properties of these molecules were found to be sensitive to Zn2+, that is, addition of Zn2+ enormously enhanced its fluorescence in THF. The titration experiments proved they showed good selectivity and sensitivity for Zn2+ detection with relatively low limit of detection. Job's curve and spectral studies of their corresponding zinc complex indicated that the ratio for dipyrrins and Zn2+ is 2:1, which suggested the formation of zinc complex by chelation-enhanced fluorescence (CHEF) effect should be the reason of the enhanced fluorescence. By combining dipyrrin with typical AIE-active moiety tetraphenylethylene (TPE), an AIE-active TPE-based dipyrrin was prepared. The studies of its fluorogenic Zn2+ detection confirmed that the CHEF effect together with AIE effect are responsible for the intense fluorescence, indicating the potential application as a Zn2+ detector in aqueous media.;In Chapter 3, the cyanostilbene backbone was functionalized with a terpyridine unit to construct four terpyridine-based cyanostilbene molecules with different donor substitutents. The investigation of their photophysical properties confirms that they are AIEE-active. With the effect of different electron-donating groups, their solid-state fluorescence color was adjusted from blue to orange-red successfully. According to the calculation results of their frontier molecular orbitals, terpyridine has little impacts on their luminescence, but would influence their solid-state emission obviously owing to its large steric hindrance. This class of molecules displayed higher luminescence efficiency in solid state than in their dissolved state. The twisted molecular conformation in single crystal, which effectively avoids close π-π stacking, was assumed to be responsible for the high luminescence efficiency in solid state. This kind of molecules show distinct switched fluorescence by stimuli of acid/base vapors, and this phenomenon derives from the protonation effect of nitrogen atoms in the terpyridine unit. Moreover, three of these molecules exhibit good electroluminescence properties. Especially, the crystal of non-donor substituted molecule show amplified spontaneous emission (ASE) properties, indicating this blue-emissive material can be used in multiple areas such as chemical sensor, organic light emitting diodes (OLEDs) and organic laser media.
48

The development of two novel spectroelectrochemical techniques /

Pruiksma, Richard T. January 1981 (has links)
No description available.
49

Electrochemical studies of metals in fused sodium hydroxide /

Theus, George John January 1972 (has links)
No description available.
50

Determination of pesticides in environmental and food samples by capillary electrophoresis and electroanalytical methods

麥麗玲, Mak, Lai-ling, Josephine. January 2001 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

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