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Slotted Ground Structures and Their Applications to Various Microwave ComponentsJung, Dong 16 January 2010 (has links)
This thesis discusses microstrip circuits and components with a slotted area on the ground plane. In recent years, various slot geometries have been placed on the ground plane with the purpose of reducing harmonics, producing frequency pass/stop-bands, and enhancing coupling effects. Among several ground slot geometries, a dumbbell shaped slot (DSS) is attractive because of its simple structure and easy analysis. The DSS and its applications to RF/microwave filters are studied and discussed. A lumped equivalent circuit model of the dumbbell shaped ground slot is introduced by utilizing resonator and filter theories. The accuracy of the equivalent circuit model is demonstrated through the comparison of circuit simulations and measurements. A lowpass filter (LPF) using slotted ground structure (SGS) with dumbbell shape is designed and measured to validate its theories. By using SGS techniques presented in this thesis, some other RF/microwave components such as a periodic structure, ultra-wideband bandpass filter (UWB-BPF), and rectenna with SGS-LPF are designed and tested.
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A 64-channel personal computer based image reconstruction system and applications in single echo acquisition magnetic resonance elastography and ultra-fast magnetic resonance imaging.Yallapragada, Naresh 15 May 2009 (has links)
Emerging technologies in parallel magnetic resonance imaging (MRI) with massive
receiver arrays have paved the way for ultra-fast imaging at increasingly high frame rates.
With the increase in the number of receiver channels used to implement parallel imaging
techniques, there is a corresponding increase in the amount of data that needs to be
processed, slowing down the process of image reconstruction. To develop a complete
reconstruction system which is easy to assemble in a single computer for a real-time
rendition of images is a relevant challenge demanding dedicated resources for high speed
digital data transfer and computation. We have enhanced a 64 channel parallel receiver
system designed for single echo acquisition (SEA) MRI into a real-time imaging system
by interfacing it with two commercially available digital signal processor (DSP) boards
which are capable of transferring large amounts of digital data via a dedicated bus from
two high performance digitizer boards. The resulting system has been used to demodulate
raw image data in real-time data and store them at rates of 200 frames per second (fps)
and subsequently display the processed data at rates of 26 fps. A further interest in realtime
reconstruction techniques is to reduce the data handling issues. Novel ways to
minimize the digitized data are presented using reduced sampling rate techniques. The
proposed techniques reduce the amount of data generated by a factor of 5 without
compromising the SNR and with no additional hardware. Finally, the usability of this tool
is demonstrated by investigating fast imaging applications. Of particular interest among
them are MR elastography applications. An exploratory study of SEA MRE was done to study the temperature dependency of shear stiffness in an agarose gel and the results
correlate well with existing literature. With the ability to make MRE images in a single
echo, the SEA MRE technique has an advantage over the conventional MRE techniques.
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Spectroscopie ultra-brève de particules d'aérosols et microcavitésCourvoisier, François Wolf, Jean-Pierre. January 2005 (has links) (PDF)
Reproductin de : Thèse de doctorat : Physique : Lyon 1 : 2005. / Titre provenant de l'écran titre. Bibliogr. en fin de chapitres.
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Influence of ultra-endurance exercise on immunoglobulin isotypes and subclassesMcKune, AJ, Smith, LL, Semple, SJ, Wadee, AA 30 January 2005 (has links)
Background: Strenuous exercise is associated with tissue damage. This activates the innate immune system
and local inflammation. Interaction between innate and adaptive immunity is essential for maintaining
health, suggesting that the adaptive immune system may also be altered by exercise.
Objectives: To determine exercise induced changes in the adaptive immune system by measuring the
immunoglobulin isotype and subclass response to an ultra-marathon.
Methods: Venepuncture was performed on 11 experienced volunteers (six men, five women; mean (SD)
age 43 (9.8) years) 24 hours before the projected finishing time and immediately after and 3, 24, and
72 hours after an ultra-marathon (90 km). Serum was stored at 280˚C. IgM, IgD, IgA, IgG, IgG1, 2, 3,
and 4, and total IgE were measured.
Results: The following immunoglobulins were significantly (p(0.05) altered after the race: IgD,
immediately (251%) and 24 hours (241%) after; IgM 24 hours after (223%); total IgG immediately after
(+12%). There were no reports of symptoms of upper respiratory tract infections after the ultra-marathon.
Conclusions: In experienced ultra-endurance runners, alterations in immunoglobulin concentrations after a
race suggest an enhanced immune response, including isotype switching, interactions with the innate
immune system, and a secondary antibody response. These alterations may have a role in the
maintenance of subject health after an ultra-marathon.
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Atmospheric ultraviolet absorption spectroscopy / by J.L. LeanLean, Judith L. January 1980 (has links)
Typescript (photocopy) / xii, 285 leaves [16] leaves of plates (some col.) : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1982
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Atmospheric ultraviolet absorption spectroscopy /Lean, Judith L. January 1980 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Physics, 1982. / Typescript (photocopy).
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Champs laser intenses ultracourts : application à la mesure et création d'impulsions attosecondes et à l'imagerie de paquets d'ondes moléculaires par explosion coulombienneConstant, Éric. January 1997 (has links)
Thèses (Ph.D.)--Université de Sherbrooke (Canada), 1997. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.
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Pulsed ultra-wideband : transmission, detection, and performance /Zhao, Shiwei. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 112-117). Also available on the World Wide Web.
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A channelized digital receiver design for UWB sytems in a multipath indoor environment /Chang, Yuhao. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 58-59). Also available on the World Wide Web.
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Étude sur la génération de supercontinuum dans l'infrarouge /Fortin, Vincent, January 2009 (has links) (PDF)
Thèse (M.Sc.)--Université Laval, 2009. / Bibliogr.: f. [103]-107. Publié aussi en version électronique dans la Collection Mémoires et thèses électroniques.
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