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 234 for “"resonant frequency"”.
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Resonant Frequency: Artefacts in Response to Time
This Industrial Design graduate thesis is a response to the discussion surrounding the question, How can Design move from Green to Good? Three artefacts have been designed. These artefacts respond to a context. Context, in this body of work, is time. Time as context is about knowing the before now, …
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Low resonant frequency beam design for a piezoelectric energy harvesting device
… Large one-dimensional cantilevers of low resonant frequency would pose serious packaging problems for the device. Two--dimensional spiral beams were designed and analyzed using analytical as well as finite element methods.
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The Fundamental Resonant Frequency and Radiation Characteristics of Wide Angle Conical Antennas
… simple compact pulse power systems is the self-resonant wide-angle conical antenna. In its typical application, this antenna will radiate a transient damped sine wave pulse whose center frequency is the fundamental resonant frequency of the antenna. In order to properly design such an antenna, …
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The resonant-frequency shift of a microwave cavity caused by the high-density plasma in semiconductors, as a function of magnetic field
Thesis: Sc. D., Massachusetts Institute of Technology, Department of Physics, 1959
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A study of the effect of cracks on the resonant frequency and dynamic modulus of elasticity of insulating brick by the dynamic testing method
Vertical cracks normal to the major axis of a standard fire brick will cause a lowering of the dynamic modulus of elasticity calculated.
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Experiments to develop High Q and tunable superconducting coplanar resonators applicable for quantum bit technology
… in excess of a million have been observed. The resonant frequency as a function of temperature of a coplanar resonator is characterised in terms of the change in the number density of superconducting electrons. At lower temperatures, the resonant frequency no longer follows this function, and …
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Effectiveness of grips at minimizing vibrations during field hockey hits
… the top hand during a hit experiences a higher resonant frequency. During the push the top hand experienced an average resonant frequency of 349.1 Hz, compared to the lower hand which experienced an average resonant frequency of 43.95 Hz. During the strike the top hand experienced an average …
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Optimization of tunable silicon compatible microring filters
… For high quality signal transmission, the resonant frequency of the filter has to be held at certain value to allow minimum timing errors in the sampling of the signal. Thermal tuning is used to compensate for any fabrication errors or environmental temperature fluctuations that might lead …
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Magnetic microparticle trapping and mechanical excitation using domain walls in magnetic microstructures
We examined the feasibility of using the resonant frequency of magnetic bead-domain wall (DW) couples in a host fluid to measure particle size. Nickel-Iron (Permalloy) rings, made using electron beam lithography, served as the tracks for nucleating and moving DWs, and Invitrogen Dynabeads M-270 …
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Graphene NanoElectroMechanical Resonators and Oscillators
… readout technique by using graphene as frequency mixer, demonstrated resonant frequencies in range from 30 to 200 MHz. Furthermore, I developed the advanced fabrications to achieve local gate structure, which led to the real-time resonant frequency detection under resonant channel …
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Clamped-mode fixed frequency series resonant converter: off-line application, analysis and implementation
The performance of the clamped-mode series resonant converter operating at a fixed frequency is studied for off line applications. A new set of characteristics for the converter operating above and below resonant frequency has been developed by including the effect of losses in the analysis. Based …
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Methods of frequency tuning vibration based micro-generator
… inertial devices that operate at a single resonant frequency. The maximum output power is generated when the resonant frequency of the generator matches the ambient vibration frequency. The output power drops significantly if these two frequencies do not match due to the high Q-factor of …
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Resonant sensors for passive, real-time, and wireless characterization of biological analytes
<p>A passive, low-cost resonant sensor was developed with the potential application of wireless monitoring of hydrolytic enzyme activity in closed systems. The resonators are rapidly prototyped from polyimide substrates (25à µm thickness) which are coated with a thin layer of copper (35à µm …
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Multi Resonant Switched-Capacitor Converter
This thesis presents a novel Resonant Switched-Capacitor Converter with Multiple Resonant Frequencies, abbreviated as MRSCC for both high density and efficiency non-isolated large step-down Intermediate Bus Converter (IBC). Conventional Resonant Switched-Capacitor Converter (RSCC) proposed by …
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Resonance Tracking and Vibration Stabilisation of Ultrasonic Surgical Instruments
… and the load result in variations in resonant frequency and electric impedance, which negatively affect the performance of the ultrasonic surgical instrument. The aim of this work was to develop an adaptive driving system to address the issue of the resonant frequency shift and …
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Evaluation of linear and nonlinear vibration methods to characterize induced microstructural damage in portland cement-based materials
… responses also was investigated. Linear (resonant frequency, half power bandwidth) and nonlinear (fast dynamics, slow dynamics) vibration measurements, using both transverse and longitudinal modes of vibration, were applied in this study. Vibration excitation and sensing was carried out as …
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Material selection and nanofabrication techniques for electronic photonic integrated circuits
… filters with precisely spaced resonant frequencies. In this work, a fabrication strategy based on scanning-electron-beam lithography (SEBL) is presented for precisely controlling the resonant frequency of microring-resonator filters. Using this strategy it is possible to achieve …
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The effect of stiffness and mass on the dynamic response of wood floors
… parameters used to describe the vibration are resonant frequency, damping ratio, and root mean square (RMS) acceleration. The results showed that COV of joist MOE affected the fundamental frequency, and had no significant effect on damping ratio and RMS acceleration. The floor mass and …
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Electronic readout of microchannel resonators for precision mass sensing in solution by Rumi Chunara.
… optical components for resolving the sensor's resonant frequency. Piezo resistors have been fabricated on SMRs through ion implantation integrated with the existing SMR fabrication process. We fabricated two designs: one with a cantilever length of 210 pm and resonant frequency of -347 kHz, and …
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Optomechanical design, analysis, and testing of the nanosatellite optical downlink experiment
… CubeSat operators are finding that current radio frequency (RF) communications are not capable of transmitting the amount of data desired. Free Space Optical (FSO) communication systems offer an alternative to traditional RF systems that can offer data rates more than an order of magnitude faster …
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