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 685 for “"Frequency Range"”.
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Vibration of railway bridges in the audible frequency range
… modelling<br/>approach to be used up to higher frequency than conventional Finite Element methods. It has been found to offer some significant advantages over the existing<br/>bridge noise model, particularly for concrete-steel composite bridges and concrete<br/>box-section …
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New design of tuned vibration absorber for wide frequency range application
… vibration absorber (TVA) that address a broad frequency range of application, light in weight, small-scale and suitable for mobile purposes. In order to achieve this aim, the preliminary design analysis was performed using finite element analysis before validated by experimental test. There are …
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Free-field reciprocity calibration of condenser microphones in the low ultrasonic frequency range
… of condenser microphones in the low ultrasonic frequency range from 20 kHz to 160 kHz. A new, fully automated measurement set-up for free-field reciprocity calibration of 1/4-inch condenser microphones has been established, and a procedure for the calculation of the free-field sensitivity of …
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Structural relaxations of glass-forming alkali-borate and alkali-tellurite in the GHz frequency range
… technique was used to determine the high-frequency complex mechanical modulus of a series of strong glass-forming alkali-borate and fragile glass-forming alkali-tellurite systems. Lithium, sodium, and potassium, were added to the systems to determine their influence on the structure and …
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Parallel FDTD Electromagnetic Simulation of Dispersive Plasmonic Nanostructures and Opal Photonic Crystals in the Optical Frequency Range
… focus here on nanotechnologies for the optical frequency range, such as plasmonic devices and photonic crystals, which are used in many areas of engineering. Plasmonic noble metal nanoparticles are used in order to improve the photovoltaic solar cell efficiency for their forward scattering and …
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The association between exercise-induced muscle damage and cortical activity in the alpha and beta frequency range
This thesis examines the regulation of muscle function following exercise-induced muscle damage (EIMD), in an attempt to determine whether regulation occurs primarily in the muscle (neuromuscular) or further upstream. Upstream regulation has been hypothesized to occur in the lower brain structures, …
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Effect of Admixtures, Chlorides, and Moisture on Dielectric Properties of Portland Cement Concrete in the Low Microwave Frequency Range
… measure the dielectric properties of PCC at a frequency range of 100-1000 MHz. A coaxial transmission line developed at Virginia Tech was used to study the effect of moisture, type of aggregate, water/cement ratio, curing period, admixture type (microsilica, superplasticizer, and shrinkage …
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An analysis of the variation of the earth's magnetic field in the frequency range 1 to 12 cycles per day
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Geology and Geophysics, 1962.
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A simple model for the depolarizing effects of rain and ice on earth satellite links in the 10 to 30 GHz frequency range
This thesis reports the results of a thorough study into the effects of rain and ice on the polarization reuse technique for earth-space communications. Precipitation in the form of rain and ice leads to significant depolarization and attenuation of dual polarized signals above about 10 GHz. The …
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Modelling and design of compact wideband and ultra-wideband antennas for wireless communications. Simulation and measurement of planer inverted F antennas (PIFAs) for contemporary mobile terminal applications, and investigations of frequency range and radiation performance of UWB antennas with design optimisation using parametric studies.
… and good time domain performance over the entire frequency range are also necessary. In this thesis, designing and analysing printed crescent shape monopole antenna, Planar Inverted F-L Antenna (PIFLA) and Planar Inverted FF Antenna (PIFFA) are focused. A Planar Inverted FF Antenna (PIFFA) can be …
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Compact spectroscopic terahertz imaging solutions using GaAs/AlGaAs and InGaAs semiconductor nanostructures /
… gain was observed experimentally in microwave frequency range. Multimode laser operating in TEM01 mode was successfully applied for high resolution THz imaging. Innovative THz detectors – asymmetrically shaped InGaAs diodes – were applied for spectroscopic THz imaging. Sensors were used to …
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Large-scale high-density terahertz radiator and receiver Arrays on silicon chips
Electromagnetic (EM) waves in the terahertz (THz) frequency range (usually deαned as from 10⁻¹ THz to 10¹ THz) have important applications in gas sensing, non-invasive imaging, short-range ultra-high-data-rate wireline/wireless communications. Historically, due to their speed limit, silicon-based …
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Monolithic RF frontends for ubiquitous wireless connectivity
… implications for the energy efficiency, frequency range and sensitivity of the radio. Ubiquitous connectivity requires bringing online previously unconnected, closed-circuit systems. Case in point, the recently ratified 802.11p standard targets wireless access in vehicular environments. …
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Investigation of Surface States in Gallium Nitride Devices using a New High Frequency Measurement Technique
Surface states place a limitation on the high-frequency behavior of Gallium Nitride devices by causing RF dispersion. They are also a source of undesirable 1⁄f noise. This thesis specifically aims to explore techniques to address known experimental observations of dispersion phenomena of unknown …
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Dielectric dispersion of poly(vinyl acetate) solutions
… measurement of solutions were made over a frequency range of 400 cycles to 500 kilocycles. The results of these experiments indicate that a vinyl type material possesses greater flexibility than cellulose derivatives in solution and, thus, the magnitude of capacitance changes over a …
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Frequency dependent impedance of stranded conductors using the subdivision method
Accurate determination of frequency dependent resistance of stranded conductors in transmission lines has not been thoroughly investigated for a wide frequency range of DCto 10 MHz. The main objective of this thesis project has been to write a computer program that calculates the resistance and …
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Padrão vocal de reconhecimento específico em Troglodytes musculus (Aves: Passeriformes: Troglodytidae) no Rio de Janeiro
… composed of trills of tonal notes with variable frequency modulation. Trills varied mainly in respect to frequency range and duration. Intersyllable interval and syllable duration were the less variable features of trills, while the minimum frequency and the variation of the frequency range …
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Radio-polarimetric observations of gravitational lenses
… under lensing. We performed high dynamic-range VLBI imaging polarimetry of the gravitational lens system B0218+357 at 43 GHz, and further VLBI observations of this system in the frequency range 8 GHz - 43 GHz. Further analysis included a low-frequency VLA study of the gravitational lens …
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