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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.
361

PREPARATION AND USE OF SOME HYDROCARBON DIANIONS IN SYNTHESIS (PENTADIENE, HEXADIENE, ALKYL, HALIDE, BROMIDE).

HSU, HOWARD FU-JYA. January 1982 (has links)
One new dianion was prepared and many alkylation and oxidation reactions of this new dianion and several known dianions were carried out. These reactions provide the best synthetic routes to most of the compounds prepared. More specifically, many oxidation products were obtained when 3-methyl-1,4-pentadiene dianion was treated with alkyl bromides. A quantitative yield of substitution product was obtained by reacting this dianion with trimethylsilyl chloride. New compounds obtained by treating this dianion with 1,2-dichloroethane are shown below: The dianion shown below was prepared from 2,5-dimethyl-1,5-hexadiene and Lochmann's base. Many different 2,5-disubstituted 1,5-hexadienes and related compounds were made by treating this dianion with alkyl halides, sulfates and alkyl (alpha),(omega)-dihalides. Attempts to make a cyclic hexapyridyl by treating 2-methyleneallyl dianion with 6,6'-dicyano-2,2'-dipyridyl (see below) apparently failed.
362

Solute Inputs to Soil and Stream Waters in a Seasonally Snow-Covered Mountain Catchment Determined Using Ge/Si, ⁸⁷SR/⁸⁶SR and Major Ion Chemistry: Valles Caldera, New Mexico

Porter, Courtney January 2012 (has links)
Weathering releases lithogenic elements to soil and stream waters that support life in catchment ecosystems. Seasonal and inter-annual variations in hydrologic conditions change subsurface flowpaths, modifying the influence of weathering on stream waters. This study, over two climatically variable years, determined seasonal and inter-annual changes in solute sources to streams using a multi-tracer approach including major cations, strontium isotopes, germanium (Ge)/silica ratios, carbon species, and trace metals. Stream water cations display constant concentrations although discharge response was highly variable, suggesting that there is a consistent subsurface water supply. However, Sr isotope ratios, and concentrations of Ge, Fe, Al, and dissolved organic carbon, which originate from shallow soil waters, increase with the hydrograph during a wet winter snowmelt. This indicates that during a year with a thick snowpack, stream waters contain components of both shallow soilwater and groundwater during snowmelt, whereas during all other times groundwater contributes predominantly to the stream.
363

New investigations into Sandmeyer chemistry

Taylor, Alec Brian January 2000 (has links)
No description available.
364

Biochemical and cytological studies of metal-induced damage to kidney proximal tubular cells

Sargazi, Mansour January 2003 (has links)
No description available.
365

A study of helium I and II lines in the solar atmosphere

Smith, Graeme Robert January 2000 (has links)
No description available.
366

Role of cobalt(II) and manganese(II) as optical and magnetic probes of metal binding sites in proteins

Keech, Angus Miles January 1997 (has links)
No description available.
367

Spectroscopy of coupled ions

Ferrigato, Alberto January 1990 (has links)
No description available.
368

Electrospray mass spectrometry : an investigation of non- covalent interactions of histone/crown ether complexes and applied methods of computational chemistry

Nkansah, Shadrack Osei January 1996 (has links)
The focus of this research is to combine both computational as well as experimental methods to study the non-covalent interaction between a selected set of proteins with small molecules. Experimentally, a mass spectrometric technique, recently known as electrospray mass spectrometry together with the computational aspect of this research, in the area of molecular modeling and quantum mechanics would be exercised.Due to the soft ionization nature of this process, electrospray (ES) mass spectrometry (MS) has been employed to study a broad class of large proteins and their non-covalent interaction with small structures, making it possible for the mass of these complexes to _be determined with an error of less than 0.1%. For this research, a set of proteins known as histones and a class of structures known as crown ethers were chosen. The ES technique allows the proteins to be prepared in an acidic medium that protonates the basic amino acids that have been exposed by the solvent. This process leaves the protein with a lot of positive charges thereby making the analysis with a single quadrupole mass spectrometer, Extrel ELQ 400 possible. The non-covalent complexation between the histones and the crown ethers is stabilized by hydrogen bonding therefore the positive charges of the protein remain unchanged. This bonding is made possible by the ability of crown ethers to bind ammonium ion or protonated amino groups. The mass of the protein which is divided by the number of its positive charges can be determined by a new kind of linear plot constructed from the ES data. The ion currents from the electrospray ionization technique is a representation of the non-covalent complexation of the histones and the crown ethers which can be observed in the mass spectra. Other information such as, the binding constants, can be obtained from the mass spectra. / Department of Chemistry
369

Development of water-soluble Ln³⁺-doped LaF₃ nanoparticles as potential biolabels

Diamente, Peter Robert. 10 April 2008 (has links)
No description available.
370

The Recombination Rate Coefficient of Molecular Helium Ions in a Pulsed Afterglow at 1.86 Torr

Hicks, Helen Segrave 08 1900 (has links)
The recombination rate coefficient for molecular helium ions has been measured in a pulsed afterglow at 1.86 Torr as a function of electron temperature and electron density without making a priori assumptions about the functional dependence. The concentrations of the molecular ions and electrons were measured and the source terms for the molecular ions were included in the rate equation.

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