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 28 for “"Dispersion Characteristics"”.
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Numerical techniques to compute the cutoff frequencies, modal fields, and dispersion characteristics in microwave planar media
… modal fields, cutoff frequencies, and dispersion characteristics in shielded microwave planar transmission media are developed. The formulation uses the method of images to derive a Fourier series expression for the current on the inner conductor, a one-dimensional Green's function …
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Measured and Modeled Time and Angle Dispersion Characteristics of the 1.8 GHz Peer-to-Peer Radio Channel
… wideband channel. Small-scale fading characteristics are measured in detail by measuring and analyzing 160 PDPs within each local area. This thesis shows the measurement setup for the calculation of fading rate variance and angular spread and reports the first known attempt to …
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Modeling and design of near-field antennas with periodic structures
… line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, …
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Integrated full vectorial FEM, FDTD and diffraction integrals in characterising visible light propagation through lossy biological media
In this thesis, the propagation characteristics of the biological optical waveguides, considering the materials as lossy in the optical frequencies, have been analysed. It has been found that the losses present in the biological materials in optical frequencies are not negligible, and the loss …
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A Generalized Analysis of Multiple-Clad Fibers with Arbitrary Step-Indx Profiles and Applications
… analysis yields unified expressions for fields, dispersion equation and cutoff conditions for weakly guiding optical fibers with step-index but otherwise arbitrary profiles. The formulation focuses on triple-clad fibers, but can accommodate single and double-clad fibers as special limiting cases. …
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Moisture diffusion through vinyl ester/clay nanocomposites
… surface treatments resulted in different dispersion characteristics. All the samples were post cured, and the diffusivity of moisture was measured by soaking the samples in water at 25°C and noting the increase in weight with increasing time of immersion. It was found that water …
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Application of the spectral domain technique to discontinuity and spurious radiation problems in microwave circuits
… the original aperture coupling formulation. The dispersion characteristics of several practical slotted structures are presented. Third, the discontinuity and radiation effects of a thin slot in the ground plane of a microstrip line are analyzed using the spectral domain approach. The scattering …
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Synthesis and Characterization of Surface-Functionalized Magnetic Polylactide Nanospheres
… to be studied as magnetite nanoparticle dispersion stabilizers. Magnetic nanoparticles are of interest for a variety of biomedical applications including magnetic field-directed drug delivery and magnetic cell separations. Small magnetite nanoparticles are desirable due to their …
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Implementation of the Finite Difference Time Domain algorithm for the analysis of terahertz waves
… of the FDTD method for the calculation of the dispersion characteristics of plasmonic waveguides are also presented. Finally, a summary of the work carried out is presented and an outline is given for future research which can be carried out by using the FDTD method for the study of terahertz …
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Advanced fibre Bragg grating structures: design and application
… fibre Bragg grating structures covering long dispersion compensating chirped Bragg gratings, superstructured Bragg gratings for identical multiple channel operation, Bragg gratings for pulse-shaping applications and Bragg gratings for add-drop applications in high bit-rate systems. Development …
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Group Velocity Of Acoustic Waves In Plates Of Electronic Materials
In this study the propagation and dispersion characteristics of plate acoustic waves (PAW) in electronic materials are investigated experimentally. Plate acoustic waves are elastic waves that travel along a plate with thickness comparable to the wavelength of the waves. Lamb waves, a type of plate …
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Numerical modelling of transport of pollutant through soils
… properties of the unsaturated soils and the dispersion characteristics need to be obtained for such an analysis. The unsaturated flow parameters are obtained from a functional relationship between capillary pressure head and moisture saturation, and can be determined from laboratory tests on …
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Analysis and Application of Coal Seam Seismic Waves for detection of Abandoned Mines
… observed in the synthetic and real field data. Dispersion analysis of the field data shows reasonable agreement with the dispersion characteristics of the synthetic data. Using standard commonly available seismic reflection processing tools, a known and well-mapped mine was detected and located. …
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Shear flow localization in thermoviscoplastic materials and a numerical study of dynamic problems in continuous media
… in the third part of the present work, the dispersion characteristics of a non-dissipative scheme for wave propagation problems in continuous media is studied.
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Synthesis and Characterization of Polylactide-siloxane Block Copolymers as Magnetite Nanoparticle Dispersion Stabilizers
… synthesized for study as magnetite nanoparticle dispersion stabilizers. Magnetic nanoparticles are of interest in a variety of biomedical applications, including magnetic field-directed drug delivery and magnetic cell separations. Small magnetite nanoparticles are desirable due to their …
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Ridge waves
… modes. The eigenfunctions are calculated and dispersion curves are examined for a variety of ridge profiles. Increasing the slope of a ridge flank increases the frequencies of the modes it supports. In addition, the waves travelling along the flanks 'feel' the topography of the opposite side …
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Double Negative Metamaterials in Dielectric Waveguide Configurations
… reported construction of a metamaterial with DNG characteristics, applications of these materials become feasible and examination of the behavior of systems and devices a potentially fruitful topic. The most promising area of research, upon inquiry into past work related to DNG materials, proves …
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Analysis and Experimental Investigation of Wave Propagation and Energy Transfer in Mechanical Rotator Metamaterials
… governs wave behavior, imparting dispersive characteristics and frequency band structures, thereby inspiring the development of innovative devices and applications with improved functionalities, including wave filtering, acoustic cloaking, energy harvesting, and vibration isolation. Nonlinear …
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Low Frequency Edge Waves and Their Role In Coastal Dynamics
… study of the impact of topography on HKEW dispersion characteristics revealed that the group velocity of the HKEW can be very low or even zero over a wide, gently sloping continental shelf. Numerical modeling experiments indicate that when the semidiurnal HKEW traveling over a narrowing …
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Physicochemical characterisation of protein ingredients prepared from milk by ultrafiltration or microfiltration for application in formulated nutritional products
… high-protein MPCs exhibited poor wetting and dispersion characteristics during rehydration in water. Heat stability studies on unconcentrated (3.5%, 140°C) and concentrated (8.5%, 120°C) MPC suspensions, showed that suspensions prepared from high-protein MPCs coagulated much more rapidly than …
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