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Baryon spectroscopy with FLIC fermionsZanotti, James Michael. January 2002 (has links) (PDF)
"October 2002" Bibliography: p. 129-136. 1. Introduction -- 2. QCD and the standard model -- 3. The Lattice -- 4. Symanzik improvement in the Static Quark Potential -- 5. Scale determination for an improved Gluon Action -- 6. Fat-link Irrelevant Clover Fermion actions -- 7. Excited Baryons in Lattice QCD -- 8. Spin 3/2 Baryons -- 9. Conclusion. This thesis reports work done in conducting numerical simulations of Lattice QCD.
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Excited state structures of polypyridyl complexes : a spectroscopic and DFT studyHowell, Sarah Louise, n/a January 2005 (has links)
This thesis reports the spectroscopic and computational studies of a number of Cu(I), Re(I) and Ru(II) complexes of polypyridyl ligands. The ligands considered in this study were 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, dibenzo[b,j][1,10]phenanthroline, dipyrido[2,3-a:3�,2�-c]phenazine, dipyrido[2,3-a:3�,2�-c]-6,7-dichlorophenazine and dipyrido[2,3-a:3�,2�-c]-6,7-dimethylphenazine.
Density functional theory calculations were carried out on the polypyridyl ligands. Validation of the calculations was carried out by comparison of the predicted values to observables. The structures were compared to previously published X-ray crystal data. Calculated bond lengths were typically calculated to be within 0.02 Å of those in the crystal structure. The calculated vibrational spectra were compared to measured IR and Raman spectra. The correspondence between calculated and measured frequencies was quantified using the mean absolute deviation between the two sets of frequencies. This was typically found to be less than 10 cm⁻�. The robustness of the calculation was further tested by calculations on perdeuterated analogues of some of the ligands. The calculations were extended to metal moieties and validated as for the ligands.
Resonance Raman and infrared spectra of the reduced states of some Re(I) complexes are reported. The structure and spectra have been modelled by considering the radical anion of the polypyridyl ligand and the reduced state of the complex. There is improvement in the mean absolute deviation, between calculated and observed frequencies, upon incorporation of the metal moiety into the calculation. Spectra are successfully modelled confirming the validity of the modelled structures.
The resonance Raman and infrared spectra of the metal-to-ligand charge transfer excited states of some Cu(I), Re(I) and Ru(II) complexes are reported. Density functional theory calculations on the lowest energy triplet states aided in the spectral assignment of bands. Cu(I) complexes were successfully modelled with mean absolute deviations, between calculated and observed frequencies, of less than 10 cm⁻�. The spectra of the Re(I) and Ru(II) complexes were less successfully modelled. Incorporation of the Ru(II) centre into the calculation of the vibrational frequencies of dipyrido[2,3-a:3�,2�-c]phenazine complexes offers no improvement over modelling the radical anion of this polypyridyl ligand.
The excited state lifetimes of a number of polypyridyl complexes have been reported. The changes in lifetimes of similar complexes were found to be consistent with the energy gap law or changes in the conjugation of the involved polypyridyl ligand.
This project has allowed the excited state structures of a number of polypyridyl complexes to be determined using vibrational spectroscopy to validate density functional theory calculations. This has provided a study strategy that may be applied to other metal polypyridyl complexes.
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Physical characterisation of pharmaceutical solids by terahertz pulsed spectroscopy and imagingZeitler, J. Axel, n/a January 2007 (has links)
Terahertz radiation refers to a specific part of the electromagnetic spectrum, flanked by microwave and infrared radiation at the higher and lower frequency end respectively. This thesis is about the development of applications using a new source of pulsed, coherent light for the physical characterisation of solids in the pharmaceutical setting.
Terahertz radiation has excellent potential in the advancement of science but is, as yet, largely unexplored. Recent developments in semiconductor physics have made it possible to provide light at terahertz frequencies (a frequency of 1 THz equals a wavelength of 0.3 mm) in a relatively easy way. Light located in this range of the electromagnetic spectrum was very difficult to generate previously. It has unique properties in that it is possible to extract the full spectroscopic fingerprint of the materials by looking at the frequency response of the terahertz pulse. Here, vibrations of the whole molecule are probed rather than just the vibrations of single functional moieties within a molecules as is the case in infrared spectroscopy, which makes terahertz spectroscopy a very powerful tool for the analysis of the complex solid-state materials properties.
In addition to structural information it easily penetrates through most plastics and polymeric materials used as excipients for pharmaceutical tablets. It is therefore especially useful for non-destructive imaging applications.
At the example of polymorphic phase transitions, dehydration processes and crystallization experiments from the amorphous phase the potential of terahertz spectroscopy for pharmaceutical analysis was systematically investigated. In addition, a novel concept for using terahertz radiation in structural imaging of pharmaceutical dosage forms was developed.
The technology, thus far predominantly used for the analysis of inorganic materials and semiconductors in particular, is now mature enough for its application to a wider field and to help with the understanding of fundamental and exciting new challenges at the interface between physics and the life sciences.
Together with a comparison of this new technology to the established techniques in physical characterisation an initial attempt to understand and interpret the spectral information provided is presented. The potential for future applications is discussed.
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Modelling and spectroscopy of polypyridyl and porphyrin complexes for electroluminescence and solar cell applicationsWalsh, Penelope Jane, n/a January 2007 (has links)
This thesis reports the spectroscopic and computational studies of two classes of compounds, which have applications in new optoelectronic materials technology. Substituted ligands of dipyrido-[3,2a:2�,3�c]phenazine (dppz), and their Cu(I), Re(I) and Ru(II) complexes have utility in organic electroluminescent devices. A series of Zn(II) tetraphenylporphyrins with conjugated functional groups at the β-position have been used with success in liquid heterojunction dye-sensitized solar cells. The vibrational spectra and optoelectronic properties of the two classes were investigated using Raman, resonance Raman and transient resonance Raman spectroscopy, in conjunction with density functional theory methods.
Density functional theory frequency calculations were used to aid vibrational mode assignments for the dppz compounds, and show close agreement with the experimental non-resonance Raman spectra. The enhancement of modes which are localized on differing sections of the ligand was identified. The nature of the absorbing chromophores for the dppz ligands and complexes was established using resonance Raman spectroscopy in concert with vibrational assignments from calculations. Transient resonance Raman spectra of the ligands provided spectral signatures for the triplet ligand-centred state; these features were observed in the TR� spectra of the metal complexes, along with other features attributable to MLCT states.
Electroluminescent devices were fabricated using the dppz ligands and complexes as emissive dopants, and their properties investigated. The optoelectronic behaviour of the devices was found to be influenced by the mechanism of exciton formation on the dopant. The device properties were also dependent on the dopant concentration, the concentrations of other components and the driving voltage.
The electronic structure of the porphyrin compounds was investigated using time-dependent density functional theory methods. Comparison of calculated optical transitions with experimental data shows that the calculations predict trends in the optical absorption spectra with change of functional group and with increase in conjugation chain length. The calculations suggest that the electron-withdrawing substituent decreases the configuration interaction effect by breaking the degeneracy of the two lowest unoccupied MOs, and other configuration interaction effects come into play involving other frontier MOs. Interrupting the conjugation of the functional group is shown to mitigate the breakdown of the configuration interaction.
The perturbation of the normal electronic structure of the porphyrin by the substituent was also investigated using resonance Raman spectroscopy. Vibrational analysis identified bands due to the substituent, implying coupling between the porphyrin and substituent chromophores. Changes in frequency of porphyrin core modes due to the differing substituents and different metal centres were reproduced by density functional theory calculations.
This project has allowed the spectroscopic investigation of the active optical states in a number of polypyridyl and porphyrin compounds, and determined the efficacy of DFT and TDDFT calculations to predict the properties of these compounds.
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Baryon spectroscopy with FLIC fermions / James Zanotti.Zanotti, James Michael January 2002 (has links)
"October 2002" / Bibliography: p. 129-136. / ix, 136 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis reports work done in conducting numerical simulations of Lattice QCD. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2002
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Use of the Richardson-Lucy algorithm in analyzing positron annihilation spectroscopy data /Yu, Dapeng. January 2006 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available online.
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Use of the Richardson-Lucy algorithm in analyzing positron annihilation spectroscopy dataYu, Dapeng. January 2006 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
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Development of chemostats and use of redox indicators for studying redox transformations in biogeochemical matricesLemmon, Teresa L. 26 April 1995 (has links)
Graduation date: 1995
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Comparison of Wave Parameters and Spectra between WERA HF Radars and Tri-Axys BuoysWang, Mei 01 January 2008 (has links)
To establish the credibility of surface wave measurements from two phased-array WERA HF (High Frequency) radars, SEACOOS (SouthEast Atlantic Coastal Ocean Observing System) funded the Mini-Waves experiment from March to May, 2005. For this study, the surface wave parameter (significant wave height) and directional wave spectrum obtained from two WERA radars were compared with those obtained from two Tri-Axys buoys during the same period. The Wyatt (1990) method was used to obtain the directional wave spectra, and significant wave heights were obtained by integrating the directional wave spectra over all directions and the selected frequency band. The SWAN (Simulating WAve Nearshore) directional wave model was used to evaluate the comparison results between WERA radars and buoys. There was a good agreement between WERA radars and Tri-Axys buoys when the echo-Doppler spectrum had a high 2nd-order SNR (signal-to-noise) ratio. The measurements didn?t agree in low sea states when the echo-Doppler spectrum had a lower SNR. Also, strong horizontal current shear caused by Florida Current (FC) had an effect on wave propagation direction. To improve the quality of WERA radar wave measurements, a longer sampling interval (10-minute interval) and procedures to remove the effect of RFI are needed.
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Developmental Trajectories of Attention and Their Impact on Language and Severity in the Infant Siblings of Children with an Autism Spectrum DisorderIbanez, Lisa V. 17 May 2010 (has links)
Children with Autism Spectrum Disorders (ASD), and their infant siblings (ASD-siblings), exhibit deficits in their ability to shift visual attention, and to initiate and respond to joint attention. The current study examined early associations between visual attention and joint attention, and between these types of attention and later language ability and ASD severity in ASD-siblings (n = 31). This study investigated the possibility that ASD-siblings, who are at-risk for atypical development, differed from infants who have an older sibling(s) with no evidence of an ASD (Comparison-siblings; n = 23) on the following: 1) means of visual and joint attention, 2) the associations between these constructs, and 3) developmental trajectories of joint attention. Early visual attention was measured using infants' gazes at and away their parents' faces during the Face-to-Face Still-Face Protocol at 6 months. Initiating joint attention (IJA) and responding to joint attention (RJA) were measured during the Early Social Communication Scales at 8, 10, 12, 15, and 18 months. Language ability was measured with the Mullen Scales of Early Learning language at 24 and 36 months. ASD severity was measured on the Autism Diagnostic Observation Schedule at 30 months. Results indicated that ASD-siblings and Comparison-siblings were comparable in their gaze shifting and mean durations of gazes away from their parents' faces. These two components of visual attention were associated with parent behaviors, and the type of chair infants sat in. There were group differences in IJA at 10 months and RJA at 8, 15, 18 months, with ASD-siblings performing fewer behaviors than Comparison-siblings. There were developmental associations between visual and joint attention, and joint attention and later language and ASD severity. ASD-siblings differed from Comparison-siblings in their RJA development. ASD-siblings also had lower language ability and greater ASD severity than Comparison-siblings. The current study's limitations included low statistical power, and a difficulty inherent to prospective studies, which are at a disadvantage because a high proportion ASD-siblings may not develop an ASD. Nevertheless, the findings have clinical implications for the development of interventions targeting RJA behaviors within the first year of life.
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