Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 247 for “"high-field"”.
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Tunable High-Field/ High-Frequency ESR and High-Field Magnetization on Single-Molecule Clusters
… clusters have been studied by application of high magnetic fields. The magnetization has been probed with an MPMS as function of temperature and field. The combination with pulse field measurements up to 52\,T allowed determination of the magnetic exchange coupling parameters, and to probing …
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Ultra-high field (7T) magnetic resonance fingerprinting
Ultra-high field (7T+) magnetic resonance imaging (MRI) improves image quality substantially compared to normal clinical 1.5T or 3T MRI. However, 7T MRI brings new challenges pertaining to B1+ inhomogeneity, B0 inhomogeneity, increased spectral bandwidth, and RF heating. Quantitative parametric …
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Aspects of high field theory in relativistic plasmas
This thesis is concerned with plasmas and high field physics. We investigate the oscillations of relativistic plasmas using a kinetic description (Chapter II), a macroscopic fluid moment description (Chapter III), a quantum description (Chapter IV as a brief exploration) and Born-Infeld …
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Impact ionization and high-field transport in semiconductors
Aspects of high field transport related to hot electron reliability effects are investigated--with special emphasis, the phenomenon of impact ionization. Both the ionization rate itself and its effect on bulk semiconductor transport are computed by a full-band Monte Carlo algorithm for Si and …
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Excitation and readout Designs for high field spectroscopic imaging
… clinical and research domain of human imaging at high field. First, we demonstrate a method for rapid and robust acquisition of the non-uniform fields of RF excitation due to arrays that are commonly used in pTx at high field. Our method achieves high-fidelity single-slice excitation and reception …
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Dilute nitride semiconductors : band structure, scattering and high field transport
… gap, as seen in experiment. We then examine the high field transport of carriers by solving the steadystate Boltzmann transport equation and find that it is necessary to include the full distribution of N levels in order to account for the small, low-field mobility and the absence of a negative …
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High-field SANS studies of the vortex lattice in YBCO
In this thesis is presented the first high-field structural study of the vortex lattice in YBa\(_2\)Cu\(_3\)O\(_7\). Small-angle neutron scattering was used to deduce the configuration of vortices in a twinned sample of YBa\(_2\)Cu\(_3\)O\(_7\) over the field range 1–11T applied parallel to the …
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High-field transport in two-dimensional graphene and molybdenum disulfide
… in integrated-circuit technology. Understanding high-field transport in a semiconductor material is crucial not only from the perspective of fundamental device physics, but also for achieving practical device applications. Unfortunately, many of the early measurements on these materials, …
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Theoretical studies of high field electron transport in silicon devices
Restriction data tranferred 2014-07-01T11:18:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission
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High field, high efficiency terahertz pulse generation by optical rectification
The great difficulty of producing high intensity radiation in the terahertz (THz) spectral region by conventional electronics has stimulated interest in development of sources based on photonics. Optical rectification in lithium niobate is an attractive approach, because it supports high generation …
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High field dynamic nuclear polarization methods: Microwave sources and mechanisms
… For the most part, and particularly at high fields, these advances have come with continuous-wave microwave irradiation and the introduction of nitroxide-based biradicals exploiting the cross effect mechanism. In this thesis, I argue that this approach is not necessarily optimal and …
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Nonlinear modeling of high field ferroelectric ceramics for structural actuation
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.
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High field terahertz radiation : conduits to synchronized hyper spectral systems
… radiation would thus open up the possibility of highly synchronized multi-spectral systems to transform the landscape of scientific investigation and medicine among others. In this thesis, the problem of efficient conversion is tackled theoretically. A montage of novel computational techniques, …
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Substrate-dependent high-field transport and self-heating in graphene transistors
… for nanoelectronic applications due to its high and symmetrical carrier mobility, and high drift velocity compared to silicon. However, when graphene is placed on insulating substrates such as SiO2 or flexible plastics, its inherent superior qualities get suppressed by the influence of the …
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Parallel transmit pulse sequence design for ultra-high field (7T) MRI
Ultra-high field (UHF, B0 ≥ 7 T) magnetic resonance imaging (MRI) scanners allow more sensitive, faster and higher resolution imaging than clinical MRI systems at 1.5 T and 3 T. However, radiofrequency field (B+ 1) inhomogeneities can cause signal dropouts in UHF MRI. The most flexible solution to …
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High Field DNP NMR probe design and application in crystalline solids
Dynamic nuclear polarization (DNP) is a valuable tool which can be used to enhance nuclear magnetic resonance (NMR) signal intensities in a variety of biological and materials science systems, by transferring polarization from unpaired electrons to nuclei. In this thesis, the mechanical design and …
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High field DNP and cryogenic MAS NMR : novel instrumentation and applications
… of its major limiting factors. Gyrotron based high-field dynamic nuclear polarization (DNP) permits increasing the sensitivity of ssNMR by 1-2 orders magnitude, significantly extending the reach of ssNMR. Successful application of ssNMR/DNP at 5T and 9.4T stimulated interest to extending this …
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HIGH FIELD MAGNETIC RESONANCE IMAGING-BASED GEL DOSIMETRY FOR SMALL RADIATION FIELDS
Small megavoltage photon radiation fields (< 3cm diameter) are used in advanced radiation therapy techniques, such as intensity modulated radiotherapy, and stereotactic radiosurgery, as well as for cellular and preclinical radiobiology studies (very small fields, <1 mm diameter). Radiation dose …
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