The analytical utility of gold nanoparticles (AuNPs) for laser desorption/ionization mass spectrometry (LDI-MS) is examined here. An evaluation of the parameters that affect desorption/ionization show that careful treatments of AuNPs is needed, as subtle changes in the solution environment can result in subsequent changes in the mass spectra. A thorough evaluation of the parameters that affect desorption/ionization of peptides is presented here, and these parameters include: (i) AuNP-to-analyte ratio, (ii) AuNP size, (iii) solvent, (iv) AuNP surface composition, (v) pH and buffer effects, (vi) amino acid sequence, and (vii) additives such as fructose or glycerol. Specifically, controlling the AuNP-to-analyte ratio, pH, peptide composition, and AuNP size are important parameters for ionization. Additionally, effects of passivating the AuNP surface with halides or oxyanions was investigated. The presence of NaF, NaCl, NaBr, and NH4X (X = F, Cl, Br, I) were shown to not significantly affect analyte ion abundances, whereas addition of NaI strongly suppressed analyte ion yields. Further physical characterization of the NPs showed that etching had occurred, which suggests that the surface chemistry of the NPs is important for desorption/ionization. Throughout these investigations, questions remain as to what the internal energies of peptides are after the desorption/ionization event, and how energy is deposited. Peptide ion fragmentation is examined under different solution conditions to evaluate the relative internal energies of peptides, and the fragmentation pattern examined for insight into fragmentation mechanisms. The data suggest that radical species are important for fragmentation of peptides when using AuNPs. However, it is likely that multiple processes are actually directing the fragmentation. Finally, based on the data presented in this dissertation, a thermal desorption mechanism of pre-formed ions is proposed. This fundamental research is intended to lay foundations for optimizing the use of nanoparticles in routine LDI-MS analysis as well as giving insight into nanoparticle ionization mechanisms. Since very little work has been done in this area, this dissertation investigates, in detail, many of the subtle characteristics that affect desorption/ionization of biomolecules when using NPs.

Nitrogen ligands have been little studied with gold(I) and almost no chemistry has been described using anionic bridging nitrogen ligands. This dissertation concerns the impact of the bridging ligands amidinate, ArNHC(H)NAr, on the chemistry of gold(I) and, in particular, the effect of substituents on the molecular arrangement. The electronic vs. steric effect of the substituents on the molecular arrangement of gold(I) amidinates complexes is studied in detail. Tetra-, tri-, and dinuclear gold(I) amidinate complexes are synthesized and characterized using X-ray diffraction. Spectroscopic and electrochemical studies of the amidinate complexes are described. Catalytic studies suggest that gold amidinates and related gold nitrogen complexes are the best catalyst precursors for CO oxidation on TiO2 surface reported to date (87% conversion). The dinuclear gold(I) amidinate complex with a Auâ ¦Au distance of 2.711(3) Ã is rare. To our knowledge, there is only one other example of a symmetrical dinuclear gold(I) nitrogen complex. Oxidative-addition reactions to the dinuclear gold(I) complex, [Au2(2,6-Me2-form)2] are studied in detail and result in the formation of gold(II) complexes. The gold(II) amidinate complexes are the first formed with nitrogen ligands. The complexes are stable at room temperature. Mixed ligand tetranuclear gold(I) clusters and tetranuclear mixed Au-Ag metal clusters of pyrazolate and amidinate ligands are synthesized and characterized using Xray diffraction.

The molecular dynamics is employed to investigate the dynamical behavior of helical multi-shell gold nanowire with diameter < 2nm . The study can be arranged into two parts, which are part I ¡§The investigation of the dynamical behavior of 7-1 gold nanowire on different axial strain¡¨ and part II ¡§the investigation of the self-assembly of crossed multi-shell gold nanowires ¡¨. In part I: We investigate the dynamical behavior of 7-1 gold nanowire on different axial strain. Some physical properties can also be determined during the tensile process, which including the strain-stress relationship, yield stress, and bond length. Moreover, vibrational properties under different tensile strains also are discussed . In part II: The aim of this work is to investigate the effect of fixed and flexible boundary conditions during the self-assembly of crossed multi-shell gold nanowires. The atomic trajectory and deformation morphology have been discussed during the assembly process. In addition, the structure transformation has also been observed on the junction by estimating the Angular Correlation Function (ACF).

In this thesis, we successfully fabricated GOLD ( gate-overlapped LDD ) polycrystalline silicon thin-film transistors ( poly-Si TFTs ) with selectively deposited W spacers. Under appropriate deposition conditions, tungsten ( W ) films can be selectively deposited on poly-Si gate electrodes to form spacers without any additional etching process. Compared with the conventional poly-TFTs without LDD structures, our devices effectively lower the leakage current and sustain a comparable on current. The transconductance of our devices is compatible to that of conventional devices, because W-spacer acts as a part of gate electrode to induce channel when the device is operated under ON state. To further study the characteristics of W-spacer TFTs, devices with different channel thickness, spacer thickness and LDD dopant density are fabricated. It is found that thinner channel, thicker spacer and lightly doped LDD implant can effectively suppress the floating body effect and also the kink effect. By comparing device performances after plasma passivation, it is also found that small-dimensional devices have better passivation effect. Finally, the hot-carrier reliability of W-spacer TFTs is also studied. Due to the reduced electric filed on the drain side, W-spacer TFTs have better reliability than the conventional counterparts.

none

"none"

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1894. / The entire thesis text is included in file. Holograph [Handwritten and illustrated in entirety by author]. C. D. Grove determined to be Claude Devlin Grove from "Directory of Male Students and Instructors From 1871 to 1901, of the School of Mines and Metallurgy of the University of Missouri". Title from title screen of thesis/dissertation PDF file (viewed February 9, 2010)

Inaug.-diss.--München. / "Literaturverzeichnis": p. 46-49.

Thesis (M. Phil.)--University of Hong Kong, 1989.

High surface area catalysts have been studied and applied in a wide range of chemical reactions and processes. The related microscopic details of surface chemistry are important and can be effectively explored employing surface science techniques. My dissertation focuses on investigations of catalytic properties of gold, primarily using vacuum molecular beam techniques, temperature programmed desorption (TPD) measurements, reflection-absorption infrared spectroscopy (RAIRS), and density functional theory (DFT) calculations. I conducted fundamental studies of hydrogenation reactions on a H atoms pre-covered Au(111) single crystal surface with co-adsorption of various chemical compounds, including acetaldehyde (CH₃CHO), acetone (CH₃COCH₃), propionaldehyde (CH₃CH₂CHO), water (H₂O), and nitrogen dioxide (NO₂). These studies allow better understanding of hydrogenative conversions facilitated by gold catalysts, which show great promise in hydrogenation applications but for which relevant fundamental studies are lacking. The experimental results unravel the unique and remarkable catalytic activity of gold in hydrogenation reactions: i) H atoms weakly absorb on the Au(111) surface and have a low desorption activation energy of ~ 28 kJ/mol; ii) acetaldehyde can be hydrogenated to ethanol at a low temperature of < 200 K; iii) propionaldehyde can be hydrogenated to 1-proponal (CH₃CH₂CH₂OH) on H pre-covered Au(111) whereas 2-propanol (CH₃CH(OH)CH₃) cannot be formed in the reaction of acetone with hydrogen atoms; iv) a coupling reaction of aldehyde-aldehyde or aldehyde-alcohol is observed on the H pre-covered Au(111) surface at temperatures lower than 200 K and this reaction can produce various ethers (symmetrical or unsymmetrical) from aldehydes and alcohols with the corresponding chain length; v) co-adsorbed H atoms have a strong interaction with water on the gold model surface and induce the dissociation of the O-H bond in water, which cannot be dissociated on the clean surface; vi) we observed a facile reaction of NO₂ reduction on H covered Au(111) and NO is produced at 77 K, yielding high NO₂ (100 %) conversion and selectivity towards NO (100 %) upon heating the surface to ~ 120 K. These studies indicate the exceptional catalytic activity of gold and enhance the understanding of surface chemistry of classical supported Au-based catalysts at the molecular scale. / text