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- Title
- Picosecond spectroscopic study of modulation doped gallium arsenide-aluminum gallium arsenide quantum wells.
- Creator
- Xu, Xumou, Florida Atlantic University, Liu, Da Wei
- Abstract/Description
-
CW photoluminescence and picosecond excitation correlation spectroscopy techniques were utilized to characterize two dimensional carriers modulation doped in GaAs-Al0.3Ga0.7As multiple quantum wells. Three characteristic transitions have been confirmed. Temperature variation measurements showed a strong carrier-phonon coupling in the samples, which is the main mechanism responsible for the fast carrier relaxation observed. In the time resolved experiments, it was found that the carrier...
Show moreCW photoluminescence and picosecond excitation correlation spectroscopy techniques were utilized to characterize two dimensional carriers modulation doped in GaAs-Al0.3Ga0.7As multiple quantum wells. Three characteristic transitions have been confirmed. Temperature variation measurements showed a strong carrier-phonon coupling in the samples, which is the main mechanism responsible for the fast carrier relaxation observed. In the time resolved experiments, it was found that the carrier relaxation slowed down as the excitation intensity increased, which we attribute to the buildup of non-equilibrium phonons rather than the dynamic screening effect. A theoretical calculation based upon hot phonon effect is presented.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14754
- Subject Headings
- Modulation spectroscopy
- Format
- Document (PDF)
- Title
- STUDY OF A PHOTOACOUSTIC CELL FOR USE AS AN OPTICAL POWER METER.
- Creator
- GUTHRIE, RICHARD WILLIAM, Florida Atlantic University
- Abstract/Description
-
The thesis first discusses the history of the photoacoustic effect, concentrating on the early history and recent investigations of the effect in solids. It then develops the theoretical description of a cell with the front window replaced with a thermally-conductive opaque membrane. The dissertation then describes the experiments performed using this and other cell designs and analyzes the results to show that the data are consistent with the theory. Finally, the system performance as a...
Show moreThe thesis first discusses the history of the photoacoustic effect, concentrating on the early history and recent investigations of the effect in solids. It then develops the theoretical description of a cell with the front window replaced with a thermally-conductive opaque membrane. The dissertation then describes the experiments performed using this and other cell designs and analyzes the results to show that the data are consistent with the theory. Finally, the system performance as a photodetector is analyzed and recommendations for improvements and future investigations made. The Appendix describes the conventional (Rosencwaig-Gersho) theory.
Show less - Date Issued
- 1983
- PURL
- http://purl.flvc.org/fcla/dt/14150
- Subject Headings
- Optoacoustic spectroscopy
- Format
- Document (PDF)
- Title
- SYNTHESIS OF SPECTROSCOPIC REACTION MODELS FOR ELECTRON TRANSFER STUDIES BETWEEN NADH AND FAD.
- Creator
- SALINAS, JORGE ENRIQUE., Florida Atlantic University
- Abstract/Description
-
In an effort to gain detailed insight into the mechanism of electron transport in the respiratory chain, the synthesis of a reaction model approximating the first step of the sequence was attempted. The desired molecule should contain the isoalloxazine ring system, the reactive center of flavin adenine dinucleotide, and the nicotinamide ring, the reactive moiety of nicotinamide adenine dinucleotide, joined by a trimethylene bridge. The successful synthesis and characterization of many...
Show moreIn an effort to gain detailed insight into the mechanism of electron transport in the respiratory chain, the synthesis of a reaction model approximating the first step of the sequence was attempted. The desired molecule should contain the isoalloxazine ring system, the reactive center of flavin adenine dinucleotide, and the nicotinamide ring, the reactive moiety of nicotinamide adenine dinucleotide, joined by a trimethylene bridge. The successful synthesis and characterization of many intermediate confirms that the procedure being used is viable. Attainment of the actual reaction model, based on the work described herein, should occur in the near future.
Show less - Date Issued
- 1975
- PURL
- http://purl.flvc.org/fcla/dt/13741
- Subject Headings
- Electron spectroscopy
- Format
- Document (PDF)
- Title
- APPLICATION OF PHOTOACOUSTIC EFFECT WITH OPTICALLY OPAQUE AND THERMALLY THIN SOLIDS: AN OPTICAL POWER METER.
- Creator
- CHENG, KAM-HO., Florida Atlantic University
- Abstract/Description
-
This thesis begins with a general outline of the applications of photoacoustic effects belonging to the more general area of photothermal measurement techniques. Next comes a discussion of the one-dimensional theory that describes the photoacoustic effect. Then it describes the experiments performed using a photoacoustic cell with an adjustable cell length and the conventional front window replaced with an optically opaque and thermally thin disk sample. For the different samples used, most...
Show moreThis thesis begins with a general outline of the applications of photoacoustic effects belonging to the more general area of photothermal measurement techniques. Next comes a discussion of the one-dimensional theory that describes the photoacoustic effect. Then it describes the experiments performed using a photoacoustic cell with an adjustable cell length and the conventional front window replaced with an optically opaque and thermally thin disk sample. For the different samples used, most of the cell response was found to be linear with the laser beam power up to 3.5 watts. Finally, the cell's performance as a power meter is analyzed and recommendations made for future investigations.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14340
- Subject Headings
- Optoacoustic spectroscopy
- Format
- Document (PDF)
- Title
- CHARACTERIZING THE PHYSICAL PROPERTIES OF LIVING CELLS THROUGH MICROFLUIDIC IMPEDANCE SENSING.
- Creator
- Galpayage, Dona Kalpani Nisansala Udeni, Lau, Andy W.C., Du, Sarah E., Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
- Abstract/Description
-
The purpose of this research is to explore and investigate the biophysical properties of living cells using microfluidics based electrical impedance sensing (EIS) technique. It provides a non-invasive approach to detect label-free biological markers in the regulation of cellular activities even at a molecular level. We specifically focus on the development, testing, and theoretical modeling of electrical impedance spectroscopy for neuroblastoma cells and endothelial cells. First, we...
Show moreThe purpose of this research is to explore and investigate the biophysical properties of living cells using microfluidics based electrical impedance sensing (EIS) technique. It provides a non-invasive approach to detect label-free biological markers in the regulation of cellular activities even at a molecular level. We specifically focus on the development, testing, and theoretical modeling of electrical impedance spectroscopy for neuroblastoma cells and endothelial cells. First, we demonstrate that the EIS technique can be used to monitor the progressive mitochondrial fission/fusion modification in genetically modified human neuroblastoma cell lines. Our results characterize quantitatively the abnormal mitochondrial dynamics through the variations in cytoplasm conductivity. Secondly, we employ a real time EIS method to determine the biophysical properties of the junctions which join one endothelial cell with one another in a monolayer of endothelial cells. In particular, we examine the role of the protein, c-MYC oncogene, in the barrier function. Our results show that the downregulation of c-MYC oncogene enhances the endothelial barrier dysfunction associated with inflammation. Finally, we measure and find that the electrical admittance (the reciprocal of the impedance) of the monolayer of endothelial cellular networks exhibits an anomalous power law of the form, Y ∝ ωα, over a wide range of frequency, with the value of the exponent, α, depending on the severity of the inflammation. We attribute the power law to the changes of the intercellular electric permeability between neighboring endothelial cells. Thus, the inflammation gives rise to relatively smaller values of α compared to that of the no-inflammation group. Furthermore, we propose a simple percolation model of a large R-C network to confirm the emergent of power law scaling behavior of the complex admittance, suggesting that the endothelial network behaves as a complex microstructural network and its electrical properties may be simulated by a large R-C network.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013595
- Subject Headings
- Microfluidics, Impedance spectroscopy, Cells
- Format
- Document (PDF)
- Title
- Study of cell penetrating peptides with Raman spectroscopy and microscopy.
- Creator
- Ye, Jing., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the...
Show moreCell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the Antennapedia homeodomain protein of Drosophila, was measured in single, living melanoma cells. Carbon-13 labeling of the Phe residue of penetratin was used to shift the intense aromatic ring-breathing vibrational mode from 1003 to 967 cm-1, thereby enabling the peptide to be traced in cells. Difference spectroscopy and principal components analysis (PCA) were used independently to resolve the Raman spectrum of the peptide from the background cellular Raman signals., On the basis of the position of the amide I vibrational band in the Raman spectra, the secondary structure of the peptide was found to be mainly random coil and b-strand in the cytoplasm, and possibly assembling as b-sheets in the nucleus. Next, label-free transportan was studied with the same methodology. The peptide, besides predominantly a-helix, adopted a significant portion of b-sheet conformation in the cytoplasm and nucleolus, which is different from the peptide in aqueous solution. The peptide microenvironment was also probed through H-bonding reported by the tyrosine Fermi doublet. Transportan displayed a tendency to accumulate in the cytoplasm over time which was unlike penetratin, which concentrated in the nucleus. The relative concentration of CPPs in various locations of live melanoma cells was directly estimated from the Raman spectra using average Phe concentration in the cell as an internal standard., The rapid entry and almost uniform cellular distribution of both peptides, as well as the lack of correlation between peptide and lipid Raman signatures, indicated that the mechanism of CPP internalization under the conditions of study was probably non-endocytotic. Last, transportan and penetratin were studied using polarized Raman spectroscopy for more detailed vibrational spectroscopic information of the two peptides in water and TFE solutions. The majority of the bands in the Raman spectra of the peptides were highly polarized, consistent with the high symmetry of aromatic ring side chain vibrational bands dispersed throughout the spectra. This work has provided new insights into the structure of CPPs in live cells and in solutions.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3342344
- Subject Headings
- Peptides, Analysis, Infrared spectroscopy, Raman spectroscopy, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Evaluation of orientation and formulation effects on the impedance of naval special hull treatments.
- Creator
- Mann, Kristina Marie., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This research used Electrochemical Impedance Spectroscopy (EIS) as a non-destructive technique to evaluate coating performance and determine the electrochemical characteristics of Special Hull Treatments (SHT). The evaluation of the SHT system provided information on its corrosion resistance and cathodic protection-influencing characteristics. The coating's impedance was analyzed while exposed to ambient versus 4.5 MPa pressures and immersion times of 1 to 9 days in seawater. Eleven specimen...
Show moreThis research used Electrochemical Impedance Spectroscopy (EIS) as a non-destructive technique to evaluate coating performance and determine the electrochemical characteristics of Special Hull Treatments (SHT). The evaluation of the SHT system provided information on its corrosion resistance and cathodic protection-influencing characteristics. The coating's impedance was analyzed while exposed to ambient versus 4.5 MPa pressures and immersion times of 1 to 9 days in seawater. Eleven specimen types were evaluated based on coating seam orientation and composition. The data support the conclusion that there was no effect on impedance values and phase shifts due to orientation, formulation, pressure values or immersion time. However, temperature increase above 30° was shown to decrease the impedance values of the SHT specimens.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12840
- Subject Headings
- Hulls (Naval architecture), Impedance spectroscopy
- Format
- Document (PDF)
- Title
- RAMAN SPECTRUM STUDY OF PHASE I AND II OF SOLID AMMONIA (GRANEISEN PARAMETERS).
- Creator
- LUO, RENKANG, Florida Atlantic University
- Abstract/Description
-
The Raman spectra of ammonia solid I and II were studied in the lattice and intramolecular region. The study of the internal modes of phase I suggests the presence of disorder in the ordered phase. The lattice modes of phase II are, for the first time, carefully reported as two very broad lines superimposed on an overdamped feature. The results confirm the structure previously determined by neutron scattering and NMR that phase II is a typical disordered phase with space group P6,3/mmc. A...
Show moreThe Raman spectra of ammonia solid I and II were studied in the lattice and intramolecular region. The study of the internal modes of phase I suggests the presence of disorder in the ordered phase. The lattice modes of phase II are, for the first time, carefully reported as two very broad lines superimposed on an overdamped feature. The results confirm the structure previously determined by neutron scattering and NMR that phase II is a typical disordered phase with space group P6,3/mmc. A mode assignment was tentatively made and Gruneisen parameters of the two assumed translational modes calculated. In terms of the Michel-Naudts theory of rotational-translational interactions, phase II is in the slow relaxation regime. A four-band model was used for the intramolecular stretching region.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14346
- Subject Headings
- Ammonia--Spectra, Raman spectroscopy
- Format
- Document (PDF)
- Title
- Raman spectroscopic study of yttrium barium(2)(copper(1-x)iron(x))oxygen(7+delta).
- Creator
- Tanabe, Makoto., Florida Atlantic University, Liu, Da Wei
- Abstract/Description
-
Polycrystalline bulk samples with the chemical formula YBa2(Cu1-xFex)3O7+delta were fabricated by the standard solid-state reaction method, and studied through magnetic susceptibility and Raman scattering experiments. In the Raman experiments, the Cu(1)-O(1) c-axial Ag stretching mode at ~502cm^-1 was investigated extensively at temperatures ranging from 23K to 773K. The room-temperature Raman spectra indicated a trend for saturation in frequency shift (as a function of iron concentration)....
Show morePolycrystalline bulk samples with the chemical formula YBa2(Cu1-xFex)3O7+delta were fabricated by the standard solid-state reaction method, and studied through magnetic susceptibility and Raman scattering experiments. In the Raman experiments, the Cu(1)-O(1) c-axial Ag stretching mode at ~502cm^-1 was investigated extensively at temperatures ranging from 23K to 773K. The room-temperature Raman spectra indicated a trend for saturation in frequency shift (as a function of iron concentration). This was interpreted as evidence supporting the occurrence of a type of iron clustering in the (001) basal plane. Effects of such a cluster formation upon the mechanism of superconductivity were considered. The low temperature Raman spectra show that the 502cm^-1 mode frequency increased slightly with decreasing temperature for all of the studied values of iron concentration without exhibiting any anomalous behavior. In the high temperature Raman spectra, a significant softening of the 502cm^-1 mode, indicative of a phase transition onset, was observed.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14597
- Subject Headings
- Raman spectroscopy, Copper oxide superconductors
- Format
- Document (PDF)
- Title
- Measurements of the core-level shifts and investigations of the Fe 3s lineshapes in Fe-V alloys using XPS.
- Creator
- Wang, Xiaotong, Florida Atlantic University, Jordan, Robin G.
- Abstract/Description
-
A series of measurements of the various core level binding energies were carried out from pure Fe and V metals and three Fe-V alloys using x-ray photoemission spectroscopy. We observed a shift of the Fe and V core levels on alloying; we find that the binding energy shifts of the Fe core levels are small and those for V appear to increase with the number of Fe neighbors. We have also examined the relationship between the lineshape of the Fe 3s spectra and the Fe local moment in the Fe-V alloys...
Show moreA series of measurements of the various core level binding energies were carried out from pure Fe and V metals and three Fe-V alloys using x-ray photoemission spectroscopy. We observed a shift of the Fe and V core levels on alloying; we find that the binding energy shifts of the Fe core levels are small and those for V appear to increase with the number of Fe neighbors. We have also examined the relationship between the lineshape of the Fe 3s spectra and the Fe local moment in the Fe-V alloys. We find that a shoulder on the higher binding energy side of each spectrum becomes less apparent with increasing V concentration, i.e., as the local moment decreases. This implies that the spin-splitting of the Fe 3s core level may be used as a probe of the local moment in Fe-V alloys.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14782
- Subject Headings
- Photoemission, Photoelectron spectroscopy, Auger effect
- Format
- Document (PDF)
- Title
- Ophirapstanol trisulfate, a new biologically active steroid sulfate from the deep water marine sponge Topsentia ophiraphidites.
- Creator
- Gunasekera, Sarath P., Sennett, Susan H., Kelly-Borges, M., Bryant, R. W., Harbor Branch Oceanographic Institute
- Date Issued
- 1994
- PURL
- http://purl.flvc.org/FCLA/DT/3319079
- Subject Headings
- Sponges --Research, Marine natural products, NMR spectroscopy
- Format
- Document (PDF)
- Title
- An antiviral sesquiterpene hydroquinone from the marine sponge Strongylophora hartmani.
- Creator
- Wright, Amy E., Rueth, S. A., Cross, S. S.
- Date Issued
- 1991
- PURL
- http://purl.flvc.org/FCLA/DT/3332987
- Subject Headings
- Sponges, Sesquiterpenes, Marine natural products, Spectroscopy
- Format
- Document (PDF)
- Title
- Photoemission study of Shockley-type surface states on the (111) surfaces of copper-gold alloys.
- Creator
- Masliah, Lilian Regina, Florida Atlantic University, Jordan, Robin G.
- Abstract/Description
-
Angle-resolved UV photoelectron spectroscopy has been used to investigate some of the properties of the occupied Shockley-type surface states that exist on the (111) surfaces of Cu, Au, ordered Cu3Au and ordered CuAuI. These states appear in normal and off-normal spectra near the Fermi level and their binding energies are independent of photon energy; however, the intensity of their emission relative to that of the d-bands is photon energy dependent, decreasing monotonically from ArI to NeI...
Show moreAngle-resolved UV photoelectron spectroscopy has been used to investigate some of the properties of the occupied Shockley-type surface states that exist on the (111) surfaces of Cu, Au, ordered Cu3Au and ordered CuAuI. These states appear in normal and off-normal spectra near the Fermi level and their binding energies are independent of photon energy; however, the intensity of their emission relative to that of the d-bands is photon energy dependent, decreasing monotonically from ArI to NeI to HeI. As the emission angle is increased from the normal, the states move towards and eventually cross the Fermi level, and we have measured this dispersion in k space. We show that the occupied extents of the dispersion relations, delta k, are related to features of the bulk band structures. For example, in Cu and Au the surface state follows the dispersion of the uppermost occupied band edge in the vicinity of the L-point and so the delta k extent is related to the (111) neck radius on the Fermi surface. Because the changes in the delta k extents are of the same order as the experimental uncertainty, we are unable to determine precisely how they vary with composition. We have fitted the dispersion data to 'free-electron' parabolas and calculated an effective electron mass in each case; we find that the effective masses in the alloys are somewhat larger than in the pure metals. The photoemission measurements described here on CuAuI(111) are the first ever to be taken on an alloy of that composition.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15221
- Subject Headings
- Photoemission, Photoelectron spectroscopy, Alloys, Surfaces (Physics)
- Format
- Document (PDF)
- Title
- Raman spectroscopic studies of stabilized zirconia at elevated temperatures.
- Creator
- Lacher, Nathan, Florida Atlantic University, Liu, David, Charles E. Schmidt College of Science, Department of Physics
- Abstract/Description
-
Raman spectroscopy was used to determine the phase structure and phase stability of zirconia mixtures for various elevated temperatures, type and concentration of oxides added to zirconia, and fabrication process. All 8 wt.% yttria samples showed mostly the tetragonal structure at room temperature. Three of the four 8 wt.% yttria samples exhibited the tetragonal structure at elevated temperatures, while no conclusion was inferred for the powdered sample. As compared with yttria, ceria is a...
Show moreRaman spectroscopy was used to determine the phase structure and phase stability of zirconia mixtures for various elevated temperatures, type and concentration of oxides added to zirconia, and fabrication process. All 8 wt.% yttria samples showed mostly the tetragonal structure at room temperature. Three of the four 8 wt.% yttria samples exhibited the tetragonal structure at elevated temperatures, while no conclusion was inferred for the powdered sample. As compared with yttria, ceria is a less effective stabilizer with respect to the zirconia tetragonal structure. A monoclinic transformation between 400 K and 800 K was observed in the 4 wt.% yttria sample which had been processed by rapid quenching. Adding alumina to 4 wt.% yttria did not completely stabilize the tetragonal structure at or above room temperature, making it a less effective stabilizer than yttria or ceria. The phase transformation was responsible for the unusual values in the Gr uneisen parameters obtained for the 4 wt.% yttria sample.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14589
- Subject Headings
- Zirconium oxide--Spectra, Raman spectroscopy
- Format
- Document (PDF)
- Title
- Mechanistic study of chromate adhesion enhancement on aluminum 2024-T3 alloy.
- Creator
- Simmons, Ronald M., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This research investigates the influence of chromate, as a conversion coating and as an inhibitor pigment, on the adhesion of epoxy coatings to an aluminum substrate. Epoxy coatings, with and without strontium chromate (SrCrO4) inhibitor pigment, are prepared according to manufacturers' specifications on AA2024-T3 substrates, with and without chromate conversion coatings. Specimens are exposed in an environmental chamber, cycling between high and low humidity conditions. After exposure,...
Show moreThis research investigates the influence of chromate, as a conversion coating and as an inhibitor pigment, on the adhesion of epoxy coatings to an aluminum substrate. Epoxy coatings, with and without strontium chromate (SrCrO4) inhibitor pigment, are prepared according to manufacturers' specifications on AA2024-T3 substrates, with and without chromate conversion coatings. Specimens are exposed in an environmental chamber, cycling between high and low humidity conditions. After exposure, specimens are evaluated using Electrochemical Impedance Spectroscopy (EIS), ASTM D3359 cross-cut tape test, and an Environmental Scanning Electron Microscope. From the evaluation it was determined that under these exposure conditions chromate does not increase the adhesive strength between the aluminum substrate and the epoxy coating system, but does provide corrosion inhibition. Regardless of the pretreatment or the coating system, the coating fails at the interface between the substrate and the coating.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12860
- Subject Headings
- Chromium compounds, Aluminum alloys, Impedance spectroscopy
- Format
- Document (PDF)
- Title
- Electronic energy levels of some tetragonal copper ion and chromium ion complexes.
- Creator
- Davari, Mortaza., Florida Atlantic University, Perumareddi, Jayarama R.
- Abstract/Description
-
The electronic spectrum of Cu(II)(L-His)2 has been measured in the visible-near IR and UV regions. By assigning ligand field bands and by fitting the band maxima with calculated energies using angular overlap model, the structure of the complex has been deduced to be five-coordinate C4v1 The observed bands in the UV spectrum have been assigned as due to ligand-to-metal charge transfer transitions. Electronic spectra of Cu(II)(diphenylcarbazide)2 and Cr(II)(diphenylcarbazone)(H2O)4 complexes...
Show moreThe electronic spectrum of Cu(II)(L-His)2 has been measured in the visible-near IR and UV regions. By assigning ligand field bands and by fitting the band maxima with calculated energies using angular overlap model, the structure of the complex has been deduced to be five-coordinate C4v1 The observed bands in the UV spectrum have been assigned as due to ligand-to-metal charge transfer transitions. Electronic spectra of Cu(II)(diphenylcarbazide)2 and Cr(II)(diphenylcarbazone)(H2O)4 complexes have also been measured. By interpretation of the ligand field bands in these spectra, tentative structures of these complexes in solution have been proposed.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15318
- Subject Headings
- Copper compounds, Chromium compounds, Electron spectroscopy
- Format
- Document (PDF)
- Title
- Synthesis and characterization of polyazo-group IVB metallocene dichloride derivatives.
- Creator
- Kloss, John Edward, Florida Atlantic University, Carraher, Charles E., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Reaction of Group IVB metallocene dichlorides with a monoaza dye yields a polymer in which the metal is bonded to a sulfonic and a hydroxyl group. The structure and bonding of the polymer was confirmed using infrared, mass spectrometry and 1H-NMR spectroscopy. Thermo and elemental analysis was used to confirm the presence of the metal. The stability of the polydye to the monomer unit was compared employing an argon laser in the visible region.
- Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14912
- Subject Headings
- Metallocenes, Organometallic polymers, Infrared spectroscopy, Azo compounds
- Format
- Document (PDF)
- Title
- Simplex optimization of aluminum analysis by electrothermal atomic absorption spectrometry.
- Creator
- Creelman, David Karl., Florida Atlantic University, Haky, Jerome E.
- Abstract/Description
-
A novel simplex method was applied for the systematic selection of optimal concentrations of two matrix modifiers, nitric acid and magnesium nitrate, for aluminum analysis in aqueous samples using electrothermal atomic absorption spectrometry. Independent optimizations of sensitivity were performed over several practical concentration ranges for each matrix modifier and optimum concentrations were chosen by comparison of data obtained for the resulting simplexes. The results indicate a strong...
Show moreA novel simplex method was applied for the systematic selection of optimal concentrations of two matrix modifiers, nitric acid and magnesium nitrate, for aluminum analysis in aqueous samples using electrothermal atomic absorption spectrometry. Independent optimizations of sensitivity were performed over several practical concentration ranges for each matrix modifier and optimum concentrations were chosen by comparison of data obtained for the resulting simplexes. The results indicate a strong interdependency between magnesium and nitric acid in the achievement of conditions for optimum sensitivity. Using the optimized conditions, detection limits of less than 7 parts per billion of aluminum were achieved, with relative standard deviations of less than 10%. A variety of aqueous samples were analyzed yielding relative standard deviations from 2 to 10%.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15399
- Subject Headings
- Atomic absorption spectroscopy, Aluminum--Analysis
- Format
- Document (PDF)
- Title
- Influence of nitrogen availability on agar-polysaccharides from Gracilaria verrucosa strain G-16: structural analysis by NMR spectroscopy.
- Creator
- Chiles, Thomas C., Bird, Kimon T., Koehn, F. E., Harbor Branch Oceanographic Institute
- Date Issued
- 1989
- PURL
- http://purl.flvc.org/FCLA/DT/3333140
- Subject Headings
- Gracilaria verrucosa, Agar, Polysaccharides, Nitrogen, Nuclear magnetic resonance spectroscopy
- Format
- Document (PDF)
- Title
- Effects of ammonium nitrate on sensitivity for determinations of copper, iron, and manganese in sea water by atomic absorption spectrometry with pyrolytically coated graphite tubes.
- Creator
- Montgomery, John R., Peterson, Gary N., Harbor Branch Oceanographic Institute
- Date Issued
- 1980
- PURL
- http://purl.flvc.org/FCLA/DT/3331817
- Subject Headings
- Ammonium nitrate, Seawater--Analysis, Atomic absorption spectroscopy
- Format
- Document (PDF)