• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 63
  • 13
  • 7
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 104
  • 104
  • 104
  • 22
  • 18
  • 18
  • 16
  • 16
  • 14
  • 14
  • 11
  • 9
  • 8
  • 8
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

SHIFTS : simulator for the Herschel imaging fourier transform spectrometer

Lindner, John Vyvyan, University of Lethbridge. Faculty of Arts and Science January 2006 (has links)
The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on the European Space Agency's (ESA's) Herschel Space Observatory (HSO). The medium resolution spectroscopic capabilities of SPIRE are provided by an imaging Fourier transform spectrometer (IFTS). A software simulator of the SPIRE IFTS was written to generate realistic data products, making use of available qualification and test data. We present the design and implementation of the simulator. Component and end-to-end simulations were compared to results from the first SPIRE instrument proto-flight model (PFMI) test campaign conducted at the Rutherford Appleton Laboratory (RAL) in Oxford, England in 2005. Final characterization of the simulator involved the determination of astronomical quantities from the synthetic data products of a simple molecular cloud. / xix, 213 leaves : ill. (some col.) ; 29 cm.
72

Fourier transform spectroscopy of the Orion molecular cloud

Tahić, Margaret Katharine, University of Lethbridge. Faculty of Arts and Science January 2004 (has links)
The Orion Molecular Cloud (OMC) is the nearest, and thus most studied, star forming region to the Earth. To date, most of the studies conducted at submillimetre wavelenths have focused on the spectral line analysis using high resolution heterodyne recievers. However, the role of dust, which is known to be important in the evolution of the interstellar medium, can only be studied through its continuum emission. This thesis presents the first results obtained using a Fourier Transform Spectrometer (FTS) at the James Clerk Maxwell Telescope to study, simultaneously, the continuum and line components of emission on the OMC. / xiii, 139 leaves : ill. (some col.) ; 29 cm.
73

Spectral characterization of the Herschel SPIRE photometer

Spencer, Locke Dean, University of Lethbridge. Faculty of Arts and Science January 2005 (has links)
The European Space Agency's Herschel Space Observatory is comprised of three cryogenically cooled instruments commissioned to explore the far infrared/submillimetre universe. The Spectral and Photometric Imaging REceiver (SPIRE) is one of Herschel's instruments and consists of a three band imaging photometer and a two band imaging spectrometer. Canada is involved in the SPIRE project through provision of instrument development hardware and software, mission flight software, and support personnel. This thesis discusses Fourier transform spectroscopy (FTS) and FTS data processing. A detailed discussion is included on FTS phase correction, with results presented from the optimization of an enhanced Forman phase correction routine developed for this work. This thesis discusses the design, verification, and use of the hardware and software provided by Dr. Naylor's group as it relates to SPIRE verification testing. Results of the photometer characterization are presented. The current status of SPIRE and its future schedule is also discussed. / xvii, 239 leaves : ill. (some col.) ; 28 cm.
74

The measurement of the directional frequency response of microphones in ordinary rooms using fast Fourier transform analysis /

Perron, Serge. January 1984 (has links)
No description available.
75

Microwave studies of Van der Waals complexes

Connelly, James Patrick January 1993 (has links)
This thesis describes the commissioning and development of a pulsed supersonic nozzle, Fourier-transform microwave spectrometer and its application to the study of several weakly bound van der Waals complexes. A pulsed supersonic expansion, Fourier-transform microwave spectrometer based on the Flygare design with a number of modifications has been constructed with an operating range of 6-18 GHz. A homodyne detection circuit mixing signals to modulus values between dc and 1 MHz is used, requiring two measurements to determine absolute transition frequencies. Transition frequencies are measured from the power spectrum by determining the first derivative zero crossing point in a least squares fitting procedure. Semiautomation of many of the spectrometer operations has been achieved allowing unattended data collection over scans of up to 300 MHz. The microwave spectrum of Ar<sub>2</sub>-OCS and Ar<sub>2</sub>-OC<sup>34</sup>S has been observed and analysed using conventional Watson S reduction hamiltonian parameters. Effective structural parameters are derived and used in a harmonic force field analysis, based on the centrifugal distortion constants, to compare the trimer interations with a model based on the sum of dimer interactions. A series of complexes containing the nitrogen molecule undergoing tunnelling motions have been studied. Hyperfine matrix elements for the first order nuclear quadrupole interaction are derived for the coupled identical nuclei case appropriate to the rapid tunnelling motions observed. The microwave spectrum of N<sub>2</sub>-OCS is described. Tunnelling and nuclear spin statistical effects for two symmetry states are observed arising from the interchange of nitrogen nuclei. Rotational and quadrupole constants are derived; an accidental near degeneracy of two rotational levels allows the off-diagonal quadrupole coupling constant to be determined from second order effects. A tunnelling hamiltonian fitting the quadrupole coupling constants to an angular potential has been used to calculate the tunnelling frequency and barrier to N<sub>2</sub> rotation. The microwave spectrum of N<sub>2</sub>-O<sub>3</sub> and a preliminary spectrum of N<sub>2</sub>-SO<sub>3</sub> have been observed. Rotation-inversion motions of the O<sub>3</sub> and SO<sub>2</sub> moieties must be considered in addition to the N<sub>2</sub> tunnelling to fit the spectrum. Tunnelling frequencies for the O<sub>3</sub>/SO<sub>2</sub> and geared motions with the N<sub>2</sub> are derived as well as structural parameters. Modifications for production of refractory molecules and complexes by laser ablation have been made. A modified nozzle employing rods of material is used with the ablation process taking place in the nozzle throat. Modifications to obtain an expansion along the axis of the microwave cavity employ a hemispherical Fabry-Perot cavity configuration. The system has been tested on a number of diatomic molecules including PbS and CuCl.
76

Field desorption ionization fourier transform ion cyclotron resonance mass spectrometry

Schaub, Tanner Michael. Marshall, Alan G., January 1900 (has links)
Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. Alan Marshall, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed June 1, 2005). Document formatted into pages; contains xix, 146 pages. Includes bibliographical references.
77

Development of Fourier transform ion cyclotron resonance mass spectrometry for the study of ion-ion reactions /

Torres, Theresa Ann, January 1998 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references. Available also in a digital version from Dissertation Abstracts.
78

Dissociation studies of charge and structure effects on electrosprayed proteins /

Stevenson, Elizabeth, January 1998 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references. Available also in a digital version from Dissertation Abstracts.
79

Detection of condom lubricants and starches in the presence of biologicals by diffuse reflectance infrared fourier transform spectroscopy and polarized light microscopy

Moody, Hannah Leigh January 2013 (has links)
Condoms have been used in sexual assaults as a means of preventing the transmission of biological fluids. Current sexual assault evidence collection kit processing protocols do not regularly take advantage of the information that can be gathered by examining residues left by condoms during intercourse. A biphasic liquid-liquid extraction technique was developed to separate polar and non-polar condom residues, which had been collected on cotton tipped swabs. This research involved the examination of twenty condom brands by Diffuse Reflectance Infrared Fourier Transform Spectroscopy. Five brands were selected to examine the consistency of this technique when the lubricants were exposed to body and storage temperature conditions for various times and in the presence of oral, vaginal, and blood samples. Additionally, starches collected from the condoms under each of the above conditions were examined. Although all lubricants were identifiable using this IR technique, the nonoxynol-9 (spermicide) containing samples produced spectra which were not identical to those produced by nonoxynol-9 standards. Although there was a decrease in the percent transmittance within IR spectra as the time between the collection and the extraction of the swabs increased, the condom residues of interest remained identifiable at all time points examined. The use of vaginal and oral swabs in the collection caused a negligible amount of background interference, which could be eliminated through spectral subtraction of the swab.
80

Application of dispersion versus absorption (DISPA) in Fourier transform nuclear magnetic resonance and Fourier transform ion cyclotron mass spectrometry /

Craig, Edward Clayton January 1987 (has links)
No description available.

Page generated in 0.0715 seconds