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 25 for “"Wave guides."”.
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Cavity resonators and wave guides containing periodic elements
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1943.
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Anisotropic wave guides-- propagation, focusing and dispersive phenomena with applications for non-destructive testing.
… layers can be viewed and modeled as acoustic waveguides. This thesis will present the framework in which to analyze such layers. To this end, analytic solutions to the plane wave displacement and stress fields in a single layer monoclinic material will be presented The propagation, frequency, …
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Coupling of Rectangular Wave Guides Having a Common Broad Wall Which Contains Uniform Transverse Slots
Made available in DSpace on 2014-12-04T21:02:55Z (GMT). No. of bitstreams: 1 0023296.pdf: 2422644 bytes, checksum: e7700e5b4b33c980ac987103f2459fe4 (MD5) Previous issue date: 1957
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Subduction zone wave guides : deciphering slab structure using intraslab seismicity at the Chile-Peru subduction zone
… affected by the interior slab structure. The wave field of these intraslab events observed in the forearc region is profoundly influenced by a seismically slow layer atop the slab surface. This several kilometer thick low-velocity channel (wave guide) causes the entrapment of seismic energy …
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Fabrication and characterization of Phosphate-based planar waveguides activated by Er3+ ions
… is possible to fabricate phosphate-based planar wave-guides activated by rare earth ions both by sol-gel and RF-sputtering techniques. The objective of this thesis has been to evaluate various methodologies for fab-rication Phosphorous-based planar waveguides. In this context sol-gel and …
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An investigation of phase-mask diffraction patterns and fibre Bragg gratings with scanning near-field optical microscopy
… utilized for assessing the properties of optical wave-guides at an increasing rate. Here, a Scanning Near-field Optical Microscope (SNOM) has been designed and constructed in order to expand this work into an analysis of the optical and structural properties of fibre Bragg gratings, which are used …
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Electromechanical Coupling of Distributed Piezoelectric Transducers for Passive Damping of Structural Vibrations: Comparison of Network Configurations
… the basic idea of synthesizing electrical wave guides to obtain an optimal electro-mechanical energy exchange and therefore to dissipate the mechanical vibrational energy in the electric form. Modular PiezoElectroMechanical (PEM) structures are constituted by continuous elastic beams (or …
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Compactons in strongly nonlinear lattices
In the present work, we study wave phenomena in strongly nonlinear lattices. Such lattices are characterized by the absence of classical linear waves. We demonstrate that compactons – strongly localized solitary waves with tails decaying faster than exponential – exist and that they play a major …
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Fabrication and Optoelectronic Characterization of Nanoscale Resonance Structures
… have long been employed by RF and microwave devices ranging from antennas, to wave guides. These resonance structures have exhibited an enormous amount of control over the wavelength selectivity, polarization, and directivity of the electromagnetic radiation which couples to the …
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Electro-optic polymer-based monolithic waveguide devices with multi-functions of amplification switching and modulation
… small velocity mismatch for traveling wave devices, and flexible monolithic integrated capability on any interested substrates. Based on waveguides fabricated with EO polymers, our research objectives were (1) to design and fabricate amplifiers, switches, and modulators and (2) to …
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Photonic Crystals with Alternate Arrays of Rods and Holes in a Low Dielectric-Index Material
… deals with the propagation of electromagnetic waves (light beams) in periodically modulated dielectric material structures based on Maxwell’s equations. We are interested in novel light propagation characteristics in these man-made dielectric material structures for practical applications, …
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The Structure of Multipulse Solitons in the Generalised Nonlinear Schrödinger Equation
… different signatures. We consider a stationary wave solution ansatz, where the optical pulse does not undergo a change in shape while propagating. This allows us to transform the quartic GNLSE into a fourth-order nonlinear ordinary differential equation (ODE), which we use to find bi-asymptotic …
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New concepts in energy and mass transport within carbon nanotubes
… diodes, field-effect transistors, and phonon wave guides due to their high axial electrical and thermal conductivity. Also, their subnanometer scale with atomically smooth surfaces is promising for selective mass transport in nanoscale, such as molecular transport, selective gas permeation, …
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Thin film integrated optical waveguides for biosensing using local evanescent field detection
A waveguide is a high refractive index material that is surrounded by lower refractive index cladding. This waveguide structure can be used to carry light confined to the high refractive index core. Surrounding the core of the waveguide is a decaying evanescent light field that extends into the …
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S band narrow-wall slotted waveguide antenna For high-power applications
… of novel antennas, such as the rectangular waveguide narrow-wall longitudinal-aperture antenna arrays for S band high power applications. This antenna is designed to perform as a uniform array with minimum power reflected into the feed-waveguide. Based on the configuration, the …
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Rectangular waveguide narrow-wall longitudinal-aperture antenna arrays for high-power applications
… with the design and bench test of rectangular waveguide narrow-wall longitudinal-aperture antenna arrays for high power applications. The best narrow-wall longitudinal-aperture array designs in the work are called the double-narrow-wall-slot-HPB-array and the double-split-waveguide-HPB-array. …
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Simulation, Fabrication, and Characterization of Semiconductor Lasers
… different types of laser: broad area, ridge waveguide and mode locking laser. Broad area laser (BAL) is the simplest to fabricate among these three lasers which is utilized for characterization of the material, whereas the ridge waveguide laser confines light within the fabricated ridge. The …
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Nonlinear ultrasonic testing using a non-collinear approach: application to heat treatment of steels and to asphalt concrete mixtures
… micro-structural dependence of acoustic wave attenuation, velocity, and a non-linear parameter, non-collinear scattered wave amplitude. Specimens of various microstructures were prepared by means of heat treatment for 1045 and 4140 Steel. Nonlinear investigation was also performed on two …
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Numerical evaluation of wavenumbers of the acoustic waves propagating in an ice-covered ocean
We consider acoustic wave propagation in a layered ocean waveguide covered by thick ice. The standard method of separation of variables leads to a Sturm-Liouville problem in the crosssection of the waveguide. We are specifically interested in the two leading modes, the separated solutions for the …
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