Tesi: "Copper" – Grafiati

1

Clark, Susan Ferguson. "Copper status in multiple trauma patients : measurement of copper balance, serum copper and ceruloplasmin /". This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-09162005-115033/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Graca, D. S. "Effects of copper depletion on subcellular hepatic copper and biliary copper excretion in cattle". Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370105.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Clark, Susan F. "Copper status in multiple trauma patients: measurement of copper balance, serum copper and ceruloplasmin". Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39376.

Testo completo

Abstract (sommario):

see document
Changes in copper metabolism have been reported in both thermal injury and skeletal trauma; data regarding copper status in multiple trauma patients (MTP) are nonexistent. Hypercatabolism following multiple trauma may increase copper utilization, deplete copper stores and compromise cuproenzyme synthesis and function. The purpose of this study was to provide information on copper status in MTP and determine whether age, injury severity, clinical outcome or nutritional intake influenced copper status. Twenty-four hour copper losses, serum copper and ceruloplasmin were measured in 11 MTP with Injury Severity Scores (ISS) >12 at 24-48 hours post admission. Collections of biological fluids (urine, nasogastric, chest tube, drains, stools) were analyzed for copper using atomic absorption spectrophotometry (AAS) and quantified over 5 days. Serial serum copper and ceruloplasmin were determined on days 1,3,5,10,15 and patient discharge by ASS and rate nephelometry inmunoprecipition, respectively. Eight patients received parenteral nutrition (PN). Three received intravenous glucose/electrolyte infusions (IV). urine (n=11) and nasogastric losses (n=8) were statistically greater than normal (p<.001). The mean ± SEM cumulative copper losses of urine, chest tube drainage, nasogastric secretions and other drains were 790 ± 116 (n=11), 833 ± 130 (n=7), 261 ± 46 (n+8), and 150 ± 58 μg/5 d (n=8), respectively. Urinary losses represented 10 to 12 times the normal copper excretion. Serum copper on day 1 and ceruloplasmin day 3 were significantly higher than normal (p<.025). Cumulative copper balance in the IV group was - 2266 μg and -440 μg in the PN group. No relationship was found between copper loss and ISS. Patients in their twenties demonstrated the greatest urinary copper loss. The physiological and biochemical effects of extensive copper loss in the MTP require further evaluation. These patients may have a predisposition to copper deficiency due to excessive copper losses and may require increased copper supplementation.
Ph. D.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Reed, Stewart T. "Copper adsorption/desorption characteristics on copper amended soils". Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-171512/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Mao, Zhong. "Effects of copper-ligand and copper-copper interactions on excited state properties of luminescent copper (I) complexes : structural and photophysical studies /". View the Table of Contents & Abstract, 2003. http://sunzi.lib.hku.hk/hkuto/record/B26450859.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Mao, Zhong, e 毛中. "Effects of copper-ligand and copper-copper interactions on excited state properties of luminescent copper (I) complexes: structural and photophysical studies". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B45015582.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Gremillion, Eric J. "Copper Kingdom". ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/1973.

Testo completo

Abstract (sommario):

This paper thoroughly examines the production of the thesis film Copper Kingdom. From writing, directing, production design, editing, to cinematography, sound, and workflow, each aspect of the creation of Copper Kingdom is carefully detailed, with insights regarding the decisions made throughout the filmmaking process.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Törndahl, Tobias. "Atomic Layer Deposition of Copper, Copper(I) Oxide and Copper(I) Nitride on Oxide Substrates". Doctoral thesis, Uppsala University, Department of Materials Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4651.

Testo completo

Abstract (sommario):

Thin films play an important role in science and technology today. By combining different materials, properties for specific applications can be optimised. In this thesis growth of copper, copper(I) oxide and copper(I) nitride on two different substrates, amorphous SiO₂ and single crystalline α-Al₂O₃ by the so called Atomic Layer Deposition (ALD) techniques has been studied. This technique allows precise control of the growth process at monolayer level on solid substrates. Other characteristic features of ALD are that it produces films with excellent step coverage and good uniformity even as extremely thin films on complicated shaped substrates.

Alternative deposition schemes were developed for the materials of interest. It was demonstrated that use of intermediate water pulses affected the deposition pathways considerably. By adding water, the films are thought to grow via formation of an oxide over-layer instead of through a direct reaction between the precursors as in the case without water.

For growth of copper(I) nitride from Cu(hfac)₂ and ammonia no film growth occurred without adding water to the growth process. The Cu₃N films could be transformed into conducting copper films by post annealing. In copper growth from CuCl and H₂ the water affected film growth on the alumina substrates considerably more than on the fused silica substrates. The existence of surface -OH and/or -NH_x groups was often found to play an important role, according to both theoretical calculations and experimental results.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Törndahl, Tobias. "Atomic layer deposition of copper, copper(I) oxide and copper(I) nitride on oxide substrates /". Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4651.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Fitzsimons, Nuala Patricia. "Copper hydride as a precursor for supported copper catalysts". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281998.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Altass, Hatem. "HCl nanoscience at copper and copper/gold alloy surfaces". Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/50823/.

Testo completo

Abstract (sommario):

The reaction of HCl with clean, Cu(100) and (111), and Au/ Cu(100) surfaces was investigated using x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) under ultra high vacuum (UHV) conditions. Exposure of the Cu(100) and (111) samples to HCl at room temperature leads to the formation of a saturated copper chloride monolayer. In the case of Cu(100), the saturated coverage was half monolayer corresponding to a c(2x2)-Cl reconstruction (half monolayer is 7.25x1014 cm-2) while for Cu(111) it was one third monolayer consistent with the reconstruction of (√3x√3)R30o (one third monolayer 5.9x1014 cm-2). The interaction of HCl with preoxidised Cu(100) and (111) showed different behaviour from those of clean copper surface depending on the way of interaction of oxygen with copper surface. Interaction of HCl with peroxidised Cu(111) at saturation oxygen coverage leads to the adsorption of chlorine on top of the copper surface with one third coverage. In contrast, presence of oxygen on Cu(100) surface at saturation coverage or less leads to adsorb chlorine but with an excess in chlorine concentration (more than the expected c(2x2) coverage). Oxidized Cu(100) and (111) surface at elevated temperature leads to the formation multi oxide layer. The two oxide surfaces („‟44‟‟ and „‟29‟‟) observed at the Cu(111) depend on the temperature of the substrate at the time of oxidation. The (√2x2√2)R45o structure was observed on the Cu(100) surface on heating which is the same structure formed at saturation coverage at room temperature. Interaction of HCl with Cu(100) and (111) surfaces covered by multilayers of oxide lead to adsorption of chlorine on top of the copper surface with a coverage more than more than the saturation coverage. Interaction of HCl with Au/Cu(100) showed two different behaviour depending on the gold coverage. Au/Cu(100) alloy formed at half monolayer of gold coverage, forming c(2x2) structure. Exposure of the Au/Cu(100) alloy at half monolayer of gold coverage to HCl leads to the formation of c(2x2)-Cl structure with saturation coverage of half monolayer in similar manner of interaction of HCl with the clean cu(100) surface. Interaction of HCl with Au/Cu(100) surface at gold coverage more than half monolayer leads to a dealloying of the gold from the copper surface and forming the Au(111) surface. Cu-Cl formed underneath the Au(111) surface with excess of chlorine concentration.

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Kim, Eun-Hae. "Maintaining Copper Homeostasis - Molecular Studies on Bacterial Copper Transporters". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/205232.

Testo completo

Abstract (sommario):

Bacteria have evolved sophisticated cellular transport mechanisms to maintain metal homeostasis to not only utilize metals as important cofactors but also to evade the toxicity of these ions. The delicate balance is maintained by several homeostatic mechanisms that range from active cytoplasmic export, modification, sequestration, and periplasmic detoxification of toxic metals to the extracellular milieu. One mechanism involves active periplasmic extrusion of toxic substrates via a transmembrane spanning tripartite protein complex. The mechanism of substrate binding and subsequent efflux has yet to be elucidated. However, genetic, comparative genomic, biochemical, and functional analyses of the components of the heavy-metal efflux family have allowed the development of proposed models for a substrate transport pathway. The goals of this research were to identify the roles these systems play and to further characterize these systems on a molecular level to ultimately understand the mechanism of substrate transport. Elucidating a transport pathway in metal transporters allows for the development of a revised working model, which ultimately can have implications for antimicrobial drug development.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Schumer, Benjamin Nathan, e Benjamin Nathan Schumer. "Mineralogy of Copper Sulfides in Porphyry Copper and Related Deposits". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/626163.

Testo completo

Abstract (sommario):

Porphyry copper deposits represent one of the largest copper reserves on Earth. They typically contain large, low-grade reserves of primary ore and higher-grade, supergene enrichment blankets of sulfide and oxide ores. Understanding the mineralogy of porphyry copper ores and ores related to porphyry copper systems is exceedingly important for several reasons, foremost of which are the information provided by ore mineral parageneses, assemblages, and mineral chemistry on evolution of these magmatic-hydrothermal systems, and information on mineral processing characteristics of the ores. The focus of this work is to better understand the mineralogy of supergene copper sulfides in porphyry copper systems and hypogene base metal lodes related to porphyry copper systems, and use this mineralogical knowledge to improve our understanding of the processes responsible for ore formation. The objectives of this study are accomplished by two means: focusing on the crystallography and crystal chemistry of minerals, and then applying this mineralogical knowledge to a supergene sulfide enrichment blanket and hypogene massive sulfides from base metal lodes in southeastern Arizona. The discovery of a new mineral, natropalermoite, NaSr2Al4(PO4)4(OH)4, provided the opportunity to use single-crystal X-ray diffraction to solve a crystal structure, and electron-probe microanalysis (EPMA) to study the crystal chemistry of natropalermoite and how the accommodation of Na in the structure changes lengthens the unit cell along [010] and shortens it along [100] and [001] compared to its lithium analogue, palermoite. Solution of the crystal structure of the mineral nickelskutterudite, (Ni,Co,Fe)As3, allowed for the investigation of anion deficiency in minerals of the skutterudite group, a problem whose solution has eluded researchers for nearly 100 years. Two skutterudite (CoAs3) and two nickelskutterudite samples were analyzed using single-crystal X-ray diffraction, EPMA, and procrystal electron density. The results showed fully-occupied anion sites and a cation surplus, which was accommodated in the icosahedral site, proving that minerals of the skutterudite group are not anion deficient. This mineralogical knowledge was applied to the supergene enrichment blanket in the Western Copper section of the Morenci mine, Greenlee County, and hypogene massive sulfide deposits associated with a porphyry copper deposit at Bisbee, Cochise County, Arizona. This is one of very few studies of supergene sulfide blankets ever completed. One drill hole through the supergene blanket at Western Copper was examined using ore microscopy and EPMA. Results showed dominant (Cu+Fe):S ratios of 1.80 ± 0.05, 1.92 ± 0.03, and 1.10 ± 0.10, with higher (Cu+Fe):S dominant high in the blanket and low ratios dominant near the base of the blanket. These values were interpreted to be controlled by activity of Cu2+, Fe2+, and Fe3+ in solution. Massive sulfide deposits at Bisbee were investigated using ore microscopy and EPMA in order to correct the previous conflicting reports of the mineralogy and paragenesis of this famous district and interpret constraints on conditions of ore-forming fluids. Results show four types of ore: chalcopyrite-rich with hematite and/or pyrite, bornite-rich, chalcocite-rich, and a Zn-Pb association. Chalcopyrite-rich ores formed first, followed by bornite-rich and chalcocite-rich ores. All ores were formed at relatively shallow depths from oxidized, moderately sulfur-rich fluids; early fluids were higher temperature and later fluids were lower temperature and considerably more sulfidized. Zinc-lead ores formed early and were continuously dissolved and reprecipitated distal to Cu-mineralization. These patterns are similar to many other base-metal lode districts worldwide, however Bisbee contains more Zn-Pb ore than other districts with hematite-containing ores and less than those without hematite.

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Deng, Hua. "Electrochemical Deposition of Nanocrystalline Copper and Copper-Based Composite Films". NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020103-173702.

Testo completo

Abstract (sommario):

Free-standing nanocrystalline copper-based composite and particle-free copper films were produced by direct- and pulse-current plating. Nanosize 50-nm Al2O3 or 5-nm diamond particles were codeposited into a copper matrix prepared on a rotating disk electrode (RDE). The electrolytes contained CuSO4.5H2O (0.25 M), H2SO4 (0.56 M or 1.5 M), 50-nm Al2O3 (12.5 g/L or 1.0 g/L) or 5-nm diamond (0.5 g/L) particles, and gelatine (0.1 g/L, 0.05 g/L, or 0.02 g/L). The deposition was carried out at room temperature. The RDE was rotated at 1800 rpm for high-alumina particle baths (12.5 g/L) and 1000 rpm for low-alumina particle (1.0 g/L), diamond particle (0.5 g/L), and particle-free baths. The free-standing composite and copper films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), micro hardness tester, and transmission electron microscopy (TEM). Grain size and crystal texture were obtained by XRD measurement. SEM gave information on surface morphology and composition of films. The hardness of nanocrystalline materials was measured by micro hardness tester. TEM was used to confirm the presence of nanocrystalline copper grains. The uncompensated potential became more cathodic with increasing current density in pulse-current plating. The current efficiency was in the range of 0.93 ¨C 1.09 for both direct- and pulse-current plating. Gelatine concentration, the presence of nanosize dispersoids, and pH have no significant effect on electrode potential and current efficiency. Grain size decreased with increasing current density for particle-free copper and most of the composite films by direct- and pulse-current plating. The microhardness of nanocrystalline materials was increased by decreasing grain size for most of the particle-free copper and composite films. The existence of high-angle grain boundaries in nanocrystalline films resulted in negative Hall-Petch slopes. The presence of low concentration of alumina or diamond particles had no effect on grain size and microhardness. The pH had no obvious influence on grain size, microhardness, and alumina content in composite films. Random crystal texture is observed for Cu-Al2O3 composite and particle-free copper films and the (111) preferred texture for Cu-diamond composite films. The (100) preferred substrate orientation had no effect on deposit texture. The current density for both direct- and pulse-current plating had no significant effect on material texture. The presence of particles has no significant influence on nanocrystalline texture. Surface morphology varied for films made under different bath conditions. High gelatine concentration resulted in low-particle impregnation. Films made using 0.1 g/L gelatine resulted in spherical particles with grain size of 64 nm and porous surface. Films made using 0.02 g/L gelatine resulted in smooth surface with smaller grains of 40 nm. Films with high-alumina particle embedding, for example sample 7/9-1, resulted in porous and dark surface. High-alumina particle concentration (12.5 g/L) with 0.02 g/L gelatine in the deposition baths resulted in high-alumina content (0.11 wt% - 2.76 wt%) in composite films. The higher current density (297 mA/cm2) resulted in the lower alumina particle (0.076 wt%) embedding rate for the same bath parameter setting. The presence of both Al and O was found in copper-alumina composites and C element (diamond) was detected in copper-diamond composite films by EDS.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Middleton, Ruth Linda. "Alkyne coupling on copper and copper/palladium single crystal surfaces". Thesis, University of Cambridge, 1998. https://www.repository.cam.ac.uk/handle/1810/272595.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Westlake, Michael Angelo 1966. "The oxidation of copper and silver plated copper lead frames". Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278279.

Testo completo

Abstract (sommario):

The effects of thin silver films (15-210 angstroms) on the oxidation of copper alloy lead frames has been characterized. Silver films were deposited onto copper lead frames by immersion plating in a bath containing potassium silver cyanide, potassium cyanide, and a mercaptan inhibitor. The thickness of films was measured by microfocus x-ray fluorescence and cross-checked by Rutherford backscattering spectrometry. Lead frames coated with silver films were oxidized at 150 to 200°C in a controlled humidity oven. The amount of oxide formed was measured by an electrolytic reduction technique and cross-checked with weight gain measurements. Auger, ESCA, and SEM analysis were also performed on the films. A tape test was performed to obtain qualitative information on the adhesion of the films.

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Beatty, Kirk Matthew 1962. "Processing of copper aluminosilicate glasses to produce glass-copper structures". Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278284.

Testo completo

Abstract (sommario):

Copper aluminosilicate (composition Cu₂O·Al₂O₃·6SiO₂) glass was melted in an alumina crucible at 1500°C and air cooled in situ. A layer of cupric oxide was grown on the polished glass surface and its thickness measured using a scanning electron microscope (SEM). The thickness of the oxide layer was found to increase parabolically with time, with a temperature dependency that was compatible with the diffusion of copper through the layer. The cupric oxide layer was reduced to copper on roughened and polished glass surfaces using a gas mixture of 3% H₂ and 97% N₂, resulting in a glass substrate coated by copper. Adherence of the copper layer to the polished glass substrate was found to be poor. However, adherence was found to increase by roughening the surface before oxidation. Additions of NiO and CaO to the base glass were not detrimental to the production of the copper film.

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Arnold, Rebecca. "Earthworm - copper interactions". Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430943.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Faughan, Marian. "Copper and haemostasis". Thesis, University of Ulster, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284849.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Garcia-Vazquez, Valentin. "Copper oxide superconductors". Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185961.

Testo completo

Abstract (sommario):

The properties of superconducting YBa₂Cu₃O₇₋(δ) thin films have been studied. Films have been prepared by multilayer deposition followed by ex situ furnace annealing. Deposition consists of a combination of dc triode sputtering from metallic targets of Y and Cu and thermal evaporation from a BaF₂ source. Superconducting and structural properties of the films strongly depend on the annealing conditions. Several heat treatment cycles were investigated, as well as different compositions. Best results were obtained for films deposited on (100) SrTiO₃ substrates, exhibiting T(c)(onset) as high as 92 K and zero resistance by 85 K. The second part of this dissertation examines the properties of ceramic Nd₂₋ₓCeₓCuO₄₋(δ) and Nd₁ͺ₈₅Ce₀ͺ₁₅(Cu₁₋(y)Zn(y))O₄₋(δ) bulk samples. Superconducting properties are examined as a function of x and y. Accurate (± 0.001 Å) lattice parameter calculations are performed from experimental x-ray diffraction data. Comparisons with previous zinc-doping studies in the hole superconducting material La₁ͺ₈₅Sr₀ͺ₁₅CuO₄₋(δ) are made. Theoretical implications and the question of electron-hole symmetry in the copper oxide superconductors are also discussed.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Lu, Zheng-Ya. "Extraction of copper from copper-iron and copper-nickel-iron sulfide concentrates by a double roast-leach process". Thesis, Lu, Zheng-Ya (1986) Extraction of copper from copper-iron and copper-nickel-iron sulfide concentrates by a double roast-leach process. PhD thesis, Murdoch University, 1986. https://researchrepository.murdoch.edu.au/id/eprint/52722/.

Testo completo

Abstract (sommario):

A fundamental investigation into a double roast-leaeh process to extract copper from sulfide concentrates containing iron and nickel has been undertaken. The double roast-leach process involves three steps: dead roast to remove sulfur from concentrates, segregation roast to produce metallic copper, and a selective leach of copper with acidic Cu(II) sulfate/acetonitrile (AN)/H20 or Cu(II) chloride/NaCl/h2O solutions. The first part of this work investigates the application of the double roast-leach process for -the recovery of copper from copper-iron and copper-nickel-iron sulfides under a variety of roast conditions. The extent of sulfur removal from the calcine and the formation of copper ferrite were studied to test their effect on the subsequent leaching and recovery of copper. It was found that sulfur in the calcine tends to hold copper as CuS and decrease the copper recovered by leaching, whi1st the formation of ferrite has less effect on the subsequent segregation and copper leaching. A study of the effect of temperature, carbon addition, chloride addition and time on segregation roasting revealed that with about 10% carbon addition, a high efficiency of copper segregation and leaching was achieved over a relatively wide range of roasting temperatures and leaching conditions. However strict control of the roasting temperature to about 670C and carbon addition was necessary to achieve selective segregation and extraction of copper from nickel and iron-bearing sulfide concentrates. The second part of this work compares and contrasts the dissolution rates and mechanism of copper and nickel metals, NiO, Fe3O4, CuFe204 and NiFe2O4 which are the components of the segregated calcine in both the Cu(II) sulfate/AN/H20 and Cu(II) chloride leach solution systems. Both electrochemical and kinetic studies were carried out on pure synthetic minerals by using rotating disc electrodes under controlled potentials and by leaching the minerals in various leach solutions of different Eh. Both approaches complemented each other and gave good agreement and correlation. It was found that the dissolution rate of copper in both the aqueous chloride and aqueous AN/sulfate leach systems was determined by Cu(II) diffusion. The dissolution rate of nickel in aqueous chloride solutions was also determined by Cu(II) diffusion, but in aqueous AN/ sulfate solutions it was inhibited by the passivation of the nickel surface. However, under practical leach conditions there is sufficient chloride present in the segregated calcine to prevent passivation from occurring. In the absence of nickel passivation the dissolution of nickel was also controlled by Cu(II) diffusion in sulfate media. By contrast, the dissolution of magnetite was found to be affected mainly by the redox potential and proton activity(aH+)of the solution and basically unaffected by stirring. Magnetite reacted most rapidly in the presence of Cu(I) at potentials cathodic to its rest potential, and the reaction rate was directly proportional to aH+. Thus to minimise the dissolution of magnetite it was necessary to leach the calcine at high Eh and high pH. The dissolution rates of hematite and nickel, copper and zinc ferrites were determined in dilute HC1. As found with magnetite, reducing agents such as Cu(I) favoured the acid dissolution of hematite but hindered the dissolution of nickel(II) oxide. This was supported by cyclic voltammogram studies of carbon pastes of and ferrites these materials. Overall, it was established that both acidic Cu(II) sulfate/AN/ H20 and Cu(II) chloride/NaCl/H20 solutions are suitable for selective leaching of copper following double roasting.

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Taylor, Lisa N. McDonald D. G. "Physiological indicators of waterborne copper toxicity in freshwater fish /". *McMaster only, 2002.

Cerca il testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Xue, Wei. "Investigation of reacted copper(II) species in micronized copper treated wood". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/53943.

Testo completo

Abstract (sommario):

Wood preservatives using micronized particulate copper as the active ingredient recently introduced in the USA has generated controversies due to their limited intrinsic solubility compared to the conventional soluble copper treatments. Because the availability of soluble copper ions is essential for these preservatives to provide an effective treatment, concerns are centered on whether they are able to produce soluble copper, and the copper fixation mechanism of the treatment is little understood. In this thesis, micronized copper treated wood were studied using a combination of Electron Paramagnetic Resonance (EPR) spectroscopy and X-ray Fluorescence (XRF) spectroscopy. The identification and characterization of soluble and chemically fixed copper species were discussed. A calibration standard was developed to quantify the solubilized and fixed copper species in the micronized copper treated wood, which also contains unreacted particulate copper. On the basis of the experimental results, the fixation mechanism is thought to be triggered by the reaction between the carboxylic acid protons in hemicellulose and pectin of wood with the particulate copper, and the quantities of the solubilized and fixed copper species are determined by the availability of the acidic protons. Results from the studies on micronized copper treated earlywood and latewood, as well as the effect of monoethanolamine additive provided further support on the theory of the fixation mechanism. Soil exposure experiment suggested that the Cu fixation may be affected by the moisture level, organic content and metal content in the soil. Study on micronized copper treated heartwood showed that the particulate Cu may react with the resin acids in addition to the major wood components. The effects of fungal colonization and bio-incision on the pre-treatment material were also briefly discussed.
Science, Faculty of
Chemistry, Department of
Graduate

Gli stili APA, Harvard, Vancouver, ISO e altri

24

McEachern, Ernest J. "Copper(I) chloride and copper(I) cyanide-mediated transformations of alkenyltrialkylstannanes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25110.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Emera, Flory. "Method development for copper dispersion evaluation and copper-based catalysts characterization". Thesis, Uppsala universitet, Strukturkemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-206922.

Testo completo

Abstract (sommario):

N2O chemisorption technique for copper dispersion determination was developed and optimized for accurate and reproducible results. With this technique, the bulk oxidation of pre-reduced catalyst can be prevented by N2O decomposition at low temperature (30oC). Only surface copper atoms are oxidized. The amount of freshly oxidized surface coppers is determined from H2-back-titration of fixed oxygen.The impact of temperature and time of exposure during oxidation was studied. Measurements made at higher temperature (60oC) resulted in overestimation of copper dispersion due to oxygen diffusion into the bulk and sub-layers. Much longer exposure time may also have an impact on copper dispersion estimation.For accurate results and good precision, it is recommended to work under mild conditions (isothermal oxidation at 30oC for 45 min.The developed method was successfully applied to fresh and spent catalyst. As expected, the copper dispersion for fresh catalyst was significantly higher than copper dispersion for spent catalyst.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Ofstad, Johannes. "Ferromagnetic Resonance Spectroscopy Studies of Permalloy/Copper/Chromium/Copper thin films". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24417.

Testo completo

Abstract (sommario):

A theroretical and experimental study of 10Py/10Cu, 10Py/10Cu/xCr/10Cu (with x=4,7, 10,13 nm) thin films has been performed. The thin films were fabricated by the sputter deposition technique at NTNU Nanolab and afterwards a FMR-experiment were performed on them at the temperatures 180K, 210K, 240K, 280K, 330K and 360K. The anisotropy field, exchange bias and offset field were extracted and analysed. The results revealed vastly higher magnitude of anisotropy field and exchange bias for the 4 Cr film, compared to the other samples. Under 300K, the anisotropy field of 4Cr is ~60 Oe which is about 30 times larger than anisotropy field of the other samples. The exchange bias for 4Cr is ~8 Oe, which is about 10 times larger than the exchange bias of the other samples. The significant difference in exchange bias is explained by the spin-density wave amplitude, which increases for decreasing Cr-thicknesses. However, this model does not predict the large drop-off to the 7 Cr, 10 Cr and 13 Cr samples. The measurement of PyCu revealed an exchange bias of the same order as the 7-13 Cr samples, indicating that the exchange coupling between the Py and Cr layer is very weak, since it is of the same magnitude as the PyCu film. A theoretical description of H_Res and Delta H of the system was given, but not fulfilled. Factors, mainly due to spin pumping and interface effects must be identified and adapted to the equations.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Bai, Yun. "Additive Manufacturing of Copper via Binder Jetting of Copper Nanoparticle Inks". Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/95855.

Testo completo

Abstract (sommario):

This work created a manufacturing process and material system based on binder jetting Additive Manufacturing to process pure copper. In order to reduce the sintered part porosity and shape distortion during sintering, the powder bed voids were filled with smaller particles to improve the powder packing density. Through the investigation of a bimodal particle size powder bed and nanoparticle binders, this work aims to develop an understanding of (i) the relationship between printed part properties and powder bed particle size distribution, and (ii) the binder-powder interaction and printed primitive formation in binder jetting of metals. Bimodal powder mixtures created by mixing a coarse powder with a finer powder were investigated. Compared to the parts printed with the monosized fine powder constituent, the use of a bimodal powder mixture improved the powder flowability and packing density, and therefore increased the green part density (8.2%), reduced the sintering shrinkage (6.4%), and increased the sintered density (4.0%). The deposition of nanoparticles to the powder bed voids was achieved by three different metal binders: (i) a nanoparticles suspension in an existing organic binder, (ii) an inorganic nanosuspension, and (iii) a Metal-Organic-Decomposition ink. The use of nanoparticle binders improved the green part density and reduced the sintering shrinkage, which has led to an improved sintered density when high binder saturation ratios were used. A new binding mechanism based on sintering the jetted metal nanoparticles was demonstrated to be capable of (i) providing a permanent bonding for powders to improve the printed part structural integrity, and (ii) eliminating the need for organic adhesives to improve the printed part purity. Finally, the binder-powder interaction was studied by an experimental approach based on sessile drop goniometry on a powder bed. The dynamic contact angle of binder wetting capillary pores was calculated based on the binder penetration time, and used to describe the powder permeability and understand the binder penetration depth. This gained understanding was then used to study how the nanoparticle solid loading in a binder affect the binder-powder interactions and the printed primitive size, which provided an understanding for determining material compatibility and printing parameters in binder jetting.
PHD

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Gill, Paul Anthony. "Some aspects of copper thioneins in chronic copper poisoning of sheep". Thesis, Gill, Paul Anthony (1990) Some aspects of copper thioneins in chronic copper poisoning of sheep. PhD thesis, Murdoch University, 1990. https://researchrepository.murdoch.edu.au/id/eprint/53328/.

Testo completo

Abstract (sommario):

This thesis reports on investigation of the roles of metallothionein and lysosomal enzymes in the pathogenesis of chronic Cu poisoning of sheep, with and without treatment by thiomolybdates. The changes in copper, zinc and molybdenum distribution were studied in the liver, bile, kidney and blood of chronic Cu poisoned sheep using histochemical, immunohistochemical and biochemical techniques including gel filtration and subcellular fractionation. Morphological changes, particularly in the liver and kidney were investigated using light and electron microscopy. The results of gel filtrations of liver indicated that metallothioneins were the main Cu binding protein in the cytosol and lysosomal rich mitochondrial fractions. Examination of kidneys showed that metallothionein was the most important Cu storage protein in that organ. Most of the Cu in the bile of chronic Cu poisoned sheep was bound to high molecular weight proteins. Small amounts of Cu thionein-like protein were detected in the bile just prior to and during haemolysis. It appears that thiomolybdate altered the binding of Cu so that it associated with more proteins than it normally does. Metallothionein mRNA determinations suggested a·correlation between liver Zn concentration and metallothionein mRNA. Increased intracellular Cu concentrations associated with either haemolysis or thiomolybdate treatment resulted in decreased Cu extractability. Thiomolybdate appeared to alter the binding of Cu by the formation of high molecular weight complexes most of which were insoluble. Studies with radiolabelled metallothionein showed that intravenously injected metallothionein was taken up at two sites - the kidney and the lung. Injected metallothionein did not appear to damage the tubular epithelial cells. Traces of metallothionein (Fraction III) appeared to be present in cell free lysates of erythrocytes taken from sheep in haemolysis though most of the Cu in the plasma and erythrocytes collected du'.ing the prehaemolytic and haemolytic phases of chronic Cu poisoning was bound to high molecular weight proteins. It is suggested that neither Cu thioneins nor haemoglobin, both of which are in the blood at haemolysis, cause serious damage to the kidney. However, both normal and iron loaded sheep kidneys were found to be an important site of uptake of a radiolabelled lysosomal enzyme preparation. The uptake of lysosomal enzymes may be an important causal factor in producing the clinically significant damage to sheep kidney which often occurs during the haemolytic phase of chronic Cu poisoning.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Hamilton, M. A. "The optical properties of oxide films on copper and copper alloys". Thesis, London Metropolitan University, 1985. http://repository.londonmet.ac.uk/3378/.

Testo completo

Abstract (sommario):

Suitable conditions were selected to allow thin, thermal oxide films consisting of cuprous oxide only to be grown on copper and dilute copper alloy substrates. The identity of the oxide was confirmed by x-ray diffraction and coulometry. Spectral measurements covering the wavelength range 350 - 750 nm were made using an automatic, self-nulling ellipsometer. From this data the optical constants and thickness of the oxide films were computed and compared to those of the bulk oxide. The optical constants of the oxide were found to depend on the thickness of the film and the identity of the alloying addition in the substrate. The effect of different substrates on the optical constants of cuprous oxide was tested by growing thin cuprous oxide films on gold and glass substrates. Optical property changes of the oxide are attributed to space-charge effects existing at the substrate/oxide interface.

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Jonnalagadda, Krishna Praveen. "Influence of Graphite type on copper diffusion in P/M copper steels". Thesis, KTH, Materialens processteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98264.

Testo completo

Abstract (sommario):

One main reason for the use of Fe-Cu-C system in PM industry is the presence of liquid phase (copper) at the start of sintering (1120oC). The diffusion of liquid copper into iron causes swelling in the structure. This in turn can cause high dimensional change and, if not controlled properly, may cause distortion. So it is of paramount importance to control the copper diffusion. Carbon, added as graphite, reduces the swelling of copper by changing the dihedral angle. The affect of graphite on copper diffusion depends on the graphite type, particle size of graphite and heating rate. The aim of this work was to find the influence of graphite type and particle size of graphite on copper diffusion. Water Atomized iron (ASC100.29) produced in Höganäs AB was taken as the base powder. Two types of graphite were used each with two different particle sizes. Two different graphite quantities (0.2% & 0.8%) for each type was taken. Natural fine graphite (UF4), Natural coarse graphite (PG44), Synthetic fine graphite (F10) and Synthetic coarse graphite (KS44) were the graphites used in this work. Powders were compacted at 600 Mpa and the sintering was done at 1120oC for 30 minutes in 90/10 N2/H2. Dilatometry and metallographic investigation of the samples sintered in the production furnace were used to understand the graphite influence. The investigation showed that at low graphite levels (0.2%), the affect of graphite type or graphite size was not significant on copper diffusion. At high graphite levels (0.8%), synthetic graphites were more effective in reducing the swelling of copper. Influence of particle size of synthetic graphites on Cu diffusion was not significant compared to the influence of particle size of natural graphite. There was also a considerable affect of heating rate on graphite dissolution and copper swelling.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Khan, Sadia Arefin. "Electromigration analysis of high current carrying adhesive-based copper-to-copper interconnections". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44885.

Testo completo

Abstract (sommario):

"More Than Moore's Law" is the driving principle for the electronic packaging industry. This principle focuses on system integration instead of transistor density in order to achieve faster, thinner, and smarter electronic devices at a low cost. A core area of electronics packaging is interconnection technology, which enables ultra-miniaturization and high functional density. Solder bump technology is one of the original, and most common interconnection methods for flip chips. With growing demand for finer pitch and higher number of I/Os, solder bumps have been forced to smaller dimensions and therefore, are subjected to higher current densities. However, the technology is now reaching its fundamental limitations in terms of pitch, processability, and current-handling due to electromigration. Electromigration in solder bumps is one of the major causes of device failures. It is accelerated by many factors, one of which is current crowding. Current crowding is the non-uniform distribution of current at the interface of the solder bump and under-bump metallurgy, resulting in an increase in local current density and temperature. These factors, along with the formation of intermetallic compounds, can lead to voiding and ultimately failure. Electromigration in solder bumps has prevented pitch-scaling below 180-210 microns, producing a shift in the packaging industry to other interconnection approaches, specifically copper pillars with solder. This research aims to explore the electromigration resistance of an adhesive-based copper-to-copper (Cu-Cu) interconnection method without solder, which is thermo-compression bonded at a low temperature of 180C. While solder bumps are more susceptible to electromigration, Cu is capable of handling two orders of magnitude higher current density. This makes it an ideal candidate for next generation flip chip interconnections. Using finite element analysis, the current crowding and joule heating effects were evaluated for a 30 micron diameter Cu-Cu interconnection in comparison with two existing flip chip interconnection techniques, Cu pillar with solder and Pb-free solder. A test vehicle (TV) was fabricated for experimental analysis with 760 bumps arranged in an area-array format with a bump diameter of 30 micron. Thermo-mechanical reliability of the test vehicle was validated under thermal cycling from -55C to 125C. The Cu-Cu interconnections were then subjected to high current and temperature stress from 1E4 to 1E6 amps per square centimeter at a temperature of 130C. The results establish the high thermo-mechanical reliability and high electromigration resistance of the proposed Cu-Cu interconnection technology.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Legault, Richard. "Pressure induced phase transitions in copper (I) oxide and copper (II) oxide". Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10077.

Testo completo

Abstract (sommario):

We have studied samples of CuO and Cu$\sb2$O to pressures of 60 GPa and 35 GPa, respectively, using energy dispersive X-ray diffraction. Samples were studied using a gasketed diamond anvil cell, energy dispersive X-ray diffraction at the Cornell High Energy Synchrotron Source, with a Mo or Al$\sb2$O$\sb3$:Cr$\sp{3+}$ pressure gauge. In the case of Cu$\sb2$O, the two phase transitions, (cubic to hexagonal to another hexagonal) as expected were seen. In CuO no definite phase transition was seen, although indications are given for CuO at 60 GPa converting to a distorted rocksalt-type structure from the initial monoclinic structure. The volume data obtained from the pressure experiments on CuO were best fitted with the third-order Birch-Murnaghan equation of state with B$\sb0$ = 110 GPa and B$\sb0\sp\prime$ = 5.5.

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Morante, Susan Janet. "The uptake of pentachlorophenol, chromated copper arsenate and copper naphthenate by soils". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34980.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Bell, Thomas Allen. "Copper uptake and toxicity in tilapia Oreochromis niloticus exposed to copper sulphate". Thesis, University of Stirling, 1996. http://hdl.handle.net/1893/1835.

Testo completo

Abstract (sommario):

The copper uptake and toxicity of young and market-size tilapia, Oreochromis niloticus, exposed to copper sulP'hate were investigated. A series of preliminary experiments were conducted to provide requisite information for the final experiment. Preliminary experiments established uptake by the culture systems, feed and/or faeces, and. the impact of fish nutritional state on uptake. Other experiments established the median lethal concentration of copper to this species, an extrapolated minimal lethal concentration, and the optimum exposure duration and concentration for copper uptake. The remaining preliminary experiments defined the relationship between toxicity and uptake in small compared to market-size tilapia, and between muscle location (within the fillet) and copper uptake. The final experiment established the amount of copper uptake in the edible tissue of market-size tilapia after a worst-case exposure to copper sulphate. The worst-case was defined as the maximum non-lethal concentration for a period significantly exceeding that encountered in commercial production systems. The worst-case experiment comprised market-size fish (350 to 570 g) being exposed at a nominal concentration of 365 ppb copper for nine days. This study demonstrated that copper did not accumulate in the edible tissue of tilapia above that measured in non-exposed control fish. A mean level of copper in the edible muscle of non-exposed fish, as measured by atomic absorption spectometry, was 2.14 pprn (dry page weight basis), while in fish exposed to a nominal concentration of 365 ppb of copper it was found to be 2.31 ppm. These data are suitable for incorporation into a United States Food and Drug Administration, New Animal Drug Approval application for the approval of copper sulphate use as a drug for aquatic species.

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Noh, Kyungyoon. "Modeling of dielectric erosion and copper dishing in copper chemical-mechanical polishing". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32393.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references.
The phenomenal success in the manufacture of multi-layer, Ultra-Large-Scale-Integrated (ULSI) semiconductor devices is in part due to the local and global planarization capabilities of the chemical-mechanical polishing (CMP) process. At present, copper is widely used as the interconnect material in the ULSI technology. The greatest challenge in Cu CMP now is the control of wafer surface non-uniformity-primarily due to dielectric erosion and copper dishing at various scales--to within the ever stringent industry specifications. In this thesis, an integrated non-uniformity model is developed by combining wafer-, die- and feature-scale non-uniformities. A feature-scale pressure calculation scheme based on surface step-height is adopted, and the evolution of the surface in each polishing stage is modeled in terms of geometric, material and process parameters. Various pad/wafer contact mechanics regimes have been considered to model oxide erosion and Cu dishing, from submicron device level to the global wiring level. The plausible causes of erosion and dishing at wafer-, die- and feature-scales were identified and integrated into the feature-scale step-height models. Such parameters include: initial pattern geometry, wafer-scale uniformity, and Cu-to-oxide slurry selectivity, material properties, and surface topography of the pad. Based on the developed erosion and dishing models, the effects of model parameters on the wafer-surface non-uniformity in Cu CMP are discussed, and parameter sets to satisfy both dishing and erosion specifications are obtained.
(cont.) In single-step polishing, for example, the Cu deposition factor should be less than 0.1 and the wafer-scale uniformity factor needs to be greater than 0.95 to maintain both erosion and dishing within 5% of interconnect thickness across the wafer if the polishing slurry has a selectivity of 15. Results of polishing experiments on 100 mm patterned Cu wafers validated both the step- height models and the integrated non-uniformity model. Based on the present models, erosion and dishing across the wafer was bounded by predefined parameters. Additionally, as predicted by the models, it was observed that the step-heights of the slowest and the fastest dies evolve in the ratio of the wafer-scale uniformity factor.
by Kyungyoon Noh.
Ph.D.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Poudyal, Kharel Aryashree. "Pyrolysis Studies of Copper and Copper Phosphate Mixtures on a Tungsten Surface". Thesis, Southern Illinois University at Edwardsville, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10016914.

Testo completo

Abstract (sommario):

The purpose of this research is to identify the chemical species present on a tungsten filament atomizer in the moment prior to the atomization. The first sample prepared was used to investigate the effects of copper samples with phosphate modifier and the second sample investigated the effect of copper samples with pyrophosphate. The aim of this thesis is to investigate the thermal decomposition of copper phosphate on a tungsten surface. An alumina crucible was used to understand the role of tungsten. The project sought to identify the possible copper compounds that remain after drying and pyrolysis in electrothermal atomic absorption spectroscopy. This was carried out by examining the effect of mass loss with the time and temperature. Dry sample residues, prior to and following heating, were studied using thermogravimetric analysis (TGA). X-ray diffraction showed that the starting material before performing TGA analysis was copper phosphate hydrate. The observation showed the formation of copper pyrophosphate at around 600°C for different concentrations of sample prepared. The X-ray diffraction (X-RD) spectra from TGA confirmed the formation of crystalline copper pyrophosphate at around 600 °C. The well separated endo thermal effects correlate to the mass loss steps and characterize thermal behavior of copper pyrophosphate.

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Hair-Bejo, Mohd. "Gastrointestinal response to copper excess : studies on copper (and zinc) loaded rats". Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303681.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Getz, Jean. "Select cardiac copper chaperone proteins are up-regulated by dietary copper deficiency". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1489.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Baguña, Torres Julia. "Copper-64 radiopharmaceuticals for PET imaging of copper trafficking in neurological disorders". Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/copper64-radiopharmaceuticals-for-pet-imaging-of-copper-trafficking-in-neurological-disorders(7862bfd1-25ed-46db-8bf8-060e7c5e3719).html.

Testo completo

Abstract (sommario):

Copper dyshomeostasis has been identified as a pathological feature of Alzheimer’s disease (AD) and Niemann-Pick disease type C1 (NPC1), as well as other neurological disorders. However, the nature of copper dysregulation in these conditions as well as its impact on disease severity and progression remain poorly understood. The growing availability of high-resolution Positron Emission Tomography (PET) systems and copper radionuclides encourages the use of copper radiotracers to measure copper fluxes in a variety of disease states with PET imaging. In this thesis, we investigated copper trafficking at brain and whole-body levels with 64Cu-PET in preclinical models of AD and NPC1 disease. The blood-brain barrier-permeable copper-64 bis(thiosemicarbazone) complex 64Cu-GTSM was used to monitor the retention, efflux and redistribution of radiocopper within the brain, while 64Cu-acetate was used to visualise copper uptake into organs from blood plasma. In addition to these imaging studies, a new library of copper bis(thiosemicarbazone) complexes for potential use in molecular imaging applications, including measurement of copper trafficking, was generated. 64Cu-GTSM-PET revealed significant differences in 64Cu brain uptake, regional distribution and biokinetics between TASTPM transgenic AD mice and wildtype controls. Interestingly, although 64Cu-GTSM was taken up by the entire brain, the regions showing the most prominent 64Cu accumulation in TASTPM brain tissue did not coincide with the areas most affected by Aβ plaque pathology, suggesting that additional metabolic/pathological factors besides Aβ plaque deposition influence brain regional 64Cu distribution. 64Cu-acetate-PET indicated subtle but significant differences in whole-body 64Cu trafficking between TASTPM transgenic mice and healthy controls. Furthermore, 64Cu-GTSM-PET detected substantial differences in brain and blood 64Cu concentration between symptomatic NPC1 knockout mice and wildtype controls that may have added value for the diagnosis of this disorder. Taken together, these results demonstrate the potential of 64Cu-PET as a useful tool to delineate copper trafficking abnormalities associated with neurological disorders.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Holland, Jason P. "Hypoxia-Selective Copper Radiopharmaceuticals". Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491536.

Testo completo

Abstract (sommario):

This thesis presents detailed experimental and computational investigations into the chemistry of copper(II) and zinc(II) bis(thiosemicarbazonato) complexes as potential' radiopharmaceutical agents for imaging and therapy. Chapter 1 provides an introduction to the field of molecular imaging in medicine with particular emphasis on the role of positron emission tomography in oncology. Key aspects of tumour physiology are discussed, and the effects of tumour hypoxia on radiotherapy and chemotherapy are considered. A range of hypoxia-selective radiopharmaceuticals are also introduced including a review of the chemistry and biochemistry of copper(II) complexes of bis(thiosemicarbazonato) ligands. Finally, the aims of this thesis are described. Chapter 2 is divided into two sections. The first section provides a general introduction to computational chemistry and density functional theory. The second section describes computational studies on a range of copper(II) bis(thiosemicarbazonato) complexes with the specific aim of understanding the molecular origins of hypoxia-selectivity and facilitating the design of new complexes with greater hypoxia-selectivity. Chapter 3 reports detailed electrochemical, spectroscopic and computational studies aimed at elucidating the mechanism of hypoxia-selectivity of copper(II) bis(thiosemicarbazonato) complexes. Spectroelectrochemistry experiments have been used to characterise several new species. The delicate equilibria between reduction, reoxidation, protonation and ligand dissociation are also considered and a new mechanistic scheme is proposed. Chapter 4 describes the design and optimisation of a new synthetic route which facilitates rapid functionalisation of the copper(II) bis(thiosemicarbazonato) ligands with biologically active molecules. The methodology has been used to synthesise zinc(II) and copper(II) bis(thiosemicarbazonato) complexes functionalised with a diverse range of saccharides. Transmetallation from the zinc(II) analogues using copper(II) salts is described as a fast and efficient route for radiolabelling and copper64 radiolabelled complexes have been prepared and characterised by a range of in vitro and in vivo experiments. Chapter 5 describes the results obtained for several projects designed at increasing the scope of copper-based radiopharmaceuticals. Preliminary synthetic studies towards the development of complexes for imaging Parkinsonian-type diseases and strategies for dual radiolabelling are presented. Chapter 6 gives general conclusions and future prospects for the development of copper-based radiopharmaceuticals. Chapter 7 reports all experimental details.

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Aniekwe, Uchechukwu Victor. "Protection of copper coolers". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ54125.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Borden, J. Benjamin. "New-fangled copper pox /". Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1328049371&sid=17&Fmt=2&clientId=1509&RQT=309&VName=PQD.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Allaire, André. "Copper matte vacuum purification". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70215.

Testo completo

Abstract (sommario):

An investigation of copper matte vacuum purification was undertaken. A mathematical model using monatomic, diatomic sulphide and diatomic oxide vapours of the impurities was developed to explain the vacuum refining process. The model was used to predict the overall refining rates for variables such as temperature, matte grade, oxygen activity and chamber pressure of the melt.
A series of experiments was undertaken to characterize the dust produced during vacuum refining of copper matte. An attempt to selectively condense the vapours produced during the vacuum refining experiments was carried out.
The "Lift-Spray" vacuum refining process was used to refine 15 to 40 kg batches of molten copper matte containing 35 to 78% copper. The removal rates of lead, bismuth, arsenic, antimony, selenium, nickel and silver were measured under different levels of matte grade, chamber pressure, lifting gas flow rate and dissolved oxygen content in the melt. The ranges of the variables under study were from 10 to 600 pascals chamber pressure, 0 to 40 normal milliliter per second of lifting gas flow rate and 10$ sp{-16}$ to 10$ sp{-7}$ atmosphere of oxygen activity.
In conclusion, LSV refining of copper matte was shown to be a promising process. Furthermore, scale-up to industrial size is now possible. The scale-up dimensions compare well to the dimensions of the RH degassing unit presently used in the steel industry. (Abstract shortened by UMI.)

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Walker, J. J. "Biomimetic copper oxygenation systems". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372276.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Dearling, Jason L. J. "Hypoxia targeting copper complexes". Thesis, University of Kent, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297352.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Pateman, Andrew Glen. "Copper catalysed aziridination reactions". Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314288.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Lu, Qin. "Copper complexes of polyazacryptands". Thesis, Open University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298997.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Garg, Nitanshu. "Copper, cytochromes and Campylobacter". Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22930/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Jurkauskas, Valdas 1966. "Copper-catalyzed conjugate reduction". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17742.

Testo completo

Abstract (sommario):

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.
Includes bibliographical references.
Chapter 1. A highly enantioselective catalyst for the asymmetric conjugate reduction of a,- unsaturated cyclic ketones was generated upon combination of catalytic amounts of CuCl, NaOt-Bu, and a chiral bis-phosphine with poly(methylhydrosiloxane) (PMHS) as the stoichiometric reductant. In this process, chiral 3-alkylcyclopentanones were isolated in high enantiomeric excess (ee =/> 92%) and in moderate to excellent yields (42-91%). Chapter 2. Kinetic resolution, with good selectivity factors (25-52), was achieved by conjugate reduction with catalytic CuCl/NaOt-Bu/(S)-p-tol-BINAP and stoichiometric quantities of PMHS. When stoichiometric amounts of NaOt-Bu and t-BuOH were included in the reaction mixture, rapid racemization of the starting material occurred allowing for the dynamic kinetic resolution of the cyclopentenone substrates. In this process, chiral 2,4-dialkylcyclopentanones were isolated with high stereoselectivity (ee =/> 91%, dr=/>90:10) and in high yield (=/> 89%). Chapter 3. An N-heterocyclic carbene-copper chloride complex was prepared and used to catalyze the conjugate reduction of [alpha], [beta]-unsaturated carbonyl compounds. The combination of catalytic amounts of N-heterocyclic carbene-copper chloride complex and NaOt-Bu with PMHS as the stoichiometric reductant generates an active catalyst for the 1,4-reduction of tri- and tetrasubstituted a,f3-unsaturated esters and cyclic enones. The active catalytic species can also be generated in situ from 1,3-bis(2,6-di-isopropylphenyl)-imidazolium chloride and CuCl2.2H20 in the presence of NaOt-Bu and PMHS.
by Valdas Jurkauskas.
Ph.D.

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Barrow, Linda. "Copper hepatotoxicity and transport". Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35207.

Testo completo

Abstract (sommario):

Indian Childhood Cirrhosis (ICC) is associated with excessive copper ingestion and hepatic deposition, is preventable by preventing copper ingestion and is partially treatable by copper chelation. However, copper administration causes only minimal hepatic damage in the rat and an acute rather than chronic liver injury in sheep. The hypothesis is explored that a second hepatic insult is synergistic with copper in causing cirrhosis. D-galactosamine was administered, to control rats and to rats orally dosed with copper acetate, to induce an acute hepatic injury documented by serum transaminases and liver histology. Surprisingly, copper-dosed rats (liver copper 607+129 ug/g, controls 48+7) were resistant to galactosamine-induced injury. Oral copper reduced the quantitative faecal anaerobical1y cultured bacterial count, suggesting that reduction in gut-derived portal vein endotoxin may explain the protective effect. Using the carbon tetrachloride model, copper again ameliorated, rather than aggravated, the hepatic injury. Impaired prostaglandin or leukotriene synthesis are discussed as possible mechanisms. To evaluate a possible disorder of copper transport in ICC, copper distribution amongst human serum proteins was investigated. In normal adults, copper was associated with caeruloplasmin (71+4%), "transcuprein" (7+2%), albumin (19+4%) and with amino acids (2+3%). Caeruloplasmin and caeruloplasmin-copper concentrations were low in neonates and symptomatic Wilson's disease. In contrast to the neonate, Wilson's disease exhibited raised total serum copper and non-caeruloplasmin-copper. In ICC, serum levels of caeruloplasmin and caeruloplasmin-copper were normal, but transcuprein- and albumin-bound copper were elevated. Raised concentrations of non-caeruloplasmin-copper in ICC and Wilson's disease perhaps represent overspill into the serum from a copper-laden liver. In serum from children with malignancy, copper and caeruloplasmin concentrations were high as previously reported. Unexpectedly transcuprein- and albumin-bound copper were also markedly elevated. It is to be determined whether this results from tissue catabolism of caeruloplasmin or from increased hepatic caeruloplasmin synthesis and copper turnover. Caeruloplasmin gene expression was investigated in adult and neonatal rat liver, to determine whether the copper profile seen in neonates results from a pre-translational defect in caeruloplasmin synthesis. Detection of mRNA in samples of Northern blotted polyadenylated RNA, using a 32P-labelled caeruloplasmin cDNA probe, demonstrated that the mRNA species isolated from the neonates was not different from that in the adults, with an apparent size of 4400 nucleotides. A reduced mRNA detection in neonatal rats was also shown. Whether this was sufficient to account for the diminished total serum copper and caeruloplasmin oxidase activity is not understood.

Gli stili APA, Harvard, Vancouver, ISO e altri

Tesi sul tema "Copper"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili