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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Slotted Ground Structures and Their Applications to Various Microwave Components

Jung, Dong 16 January 2010 (has links)
This thesis discusses microstrip circuits and components with a slotted area on the ground plane. In recent years, various slot geometries have been placed on the ground plane with the purpose of reducing harmonics, producing frequency pass/stop-bands, and enhancing coupling effects. Among several ground slot geometries, a dumbbell shaped slot (DSS) is attractive because of its simple structure and easy analysis. The DSS and its applications to RF/microwave filters are studied and discussed. A lumped equivalent circuit model of the dumbbell shaped ground slot is introduced by utilizing resonator and filter theories. The accuracy of the equivalent circuit model is demonstrated through the comparison of circuit simulations and measurements. A lowpass filter (LPF) using slotted ground structure (SGS) with dumbbell shape is designed and measured to validate its theories. By using SGS techniques presented in this thesis, some other RF/microwave components such as a periodic structure, ultra-wideband bandpass filter (UWB-BPF), and rectenna with SGS-LPF are designed and tested.
122

Constraining the epoch of recombination with recent observations of the cosmic microwave background

Linn, Angela M., January 2003 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xv,110 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Robert J. Scherrer, Dept. of Physics. Includes bibliographical references (p. 106-110).
123

Techniques for radar imaging using a wideband adaptive array /

Curry, Mark A. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 174-175).
124

Multi-frequency microwave spectroscopy on a silicon single-electron transistor

Erfani, Morteza January 2011 (has links)
No description available.
125

Angular dependence of the line width of a planar ferrite

Nelson, Thomas Clarke, 1932- January 1963 (has links)
No description available.
126

Design and construction of a microwave paramagnetic resonance spectrograph

Cooper, DeWitt Wetzel, 1931- January 1958 (has links)
No description available.
127

Beamfilling correction study for retrieval of oceanic rain from passive microwave observations

Chen, Ruiyue 30 September 2004 (has links)
Beamfilling error is one of the main error sources for microwave oceanic rainfall retrieval. An accurate beamfilling correction can improve the rainfall retrieval accuracy significantly. Quantitative understanding of the uncertainty of the Beamfilling Correction Factor (BCF) is very important for the understanding of the accuracy of microwave passive rainfall retrieval. Refinement of the calculation of the BCF and the estimation of BCF uncertainty are the main purposes of this thesis. The characteristic of rainfall distribution is investigated. Quantitative understanding of the statistical characteristics of rainfall distribution provides an indication of the beamfilling error and the uncertainty of BCF in many ways. Some refinements to the traditional BCF calculation algorithm are provided in this thesis. Scattering is included in the new algorithm. Also the BCF calculation only considers the cases within the useful dynamic range. These refinements make the BCF calculation closer to how it is used in the retrieval algorithm. The BCF based on the new algorithm should be more accurate. The global BCF uncertainty and the local BCF uncertainty are estimated using the available A/C radar data. The results show that the uncertainty of BCF is much smaller than expected, and also show that the BCF derived from a specific set of data can be used globally.
128

Microwavevacuum and osmotic drying of cranberries

Sunjka, Predrag S. January 2003 (has links)
Modern food industry dictates strict conditions on energy use and application, preventing unnecessary energy dissipation. Energy demanding processes such as distillation and drying have to be optimised to the highest extent, while retaining or improving the final product quality. Pretreatments to drying can be used in order to optimize drying, and some of cranberry pretreatments such as chemical, mechanical and osmotic dehydration were optimized. Chemical pretreatment consisted of dipping cranberries into solution of ethyl oleate and sodium hydroxide at different temperatures, and process times. Mechanical pretreatment was cutting of berries into halves or quarters. Tested parameters for osmotic dehydration were the duration of process, osmotic agent type and its concentration. / Once the appropriate pretreatment was selected, cranberries were subjected to hybrid drying under subatmospheric pressure and using microwaves as an energy source. Evaluated process parameters were microwave power level, microwave power mode, and the operating pressure of process. This drying method showed good potential, but in order to verify the results obtained, it was compared to microwave/convective drying. Slight advantages of the microwave/vacuum process over the microwave/convective process were apparent in almost all product quality parameters, as well as in process efficiency.
129

Applications of microwave technology to wastewater treatment

Yin, Guiqing 11 1900 (has links)
A microwave enhanced advanced oxidation process using hydrogen peroxide (MW/H₂O₂-AOP) was used for the release of nutrients and the destruction of solids from secondary municipal sewage sludge. The significant factors affecting the MW/H₂O₂-AOP that would yield maximum soluble substrates were studied. Using a computer statistical software package for experimental design and data analysis, four factors including microwave heating temperature, heating time, hydrogen peroxide dosage, and sludge solids content, were selected and examined. The initial sludge TS content and hydrogen peroxide dosage were the most significant factors for the solubilization of COD and nutrients release under the experimental conditions selected in this study. Overall, the maximum solubilization of nutrients was obtained at 2.5 % of total solids content, 2% of hydrogen peroxide by weight, 5 min. of microwave heating and 120 ºC. The effects of combination of microwave treatment and oxidative reagents on solids destruction and nutrients release were also investigated. Microwave enhanced advanced oxidation processes (MW-AOP), such as MW/O₃, MW/H₂O₂ and MW/H₂O₂/O₃, were conducted at 100 °C. In terms of nutrients release and solids reduction, the MW/H₂O₂/O₃-AOP yielded the best result. Subsequently, three factors including microwave heating temperature, hydrogen peroxide dosage, and ozone dosage, were investigated. The best result, in terms of the release of phosphate and ammonia, and solids reduction, was obtained with additions of 2 % hydrogen peroxide by weight and ozone dosage of 5.09 mg/ml, and operating at 120ºC. About 95%, 32% and 78% of TP, TKN and COD were released into the solution, respectively. The microwave enhanced advanced oxidation processes, with and without an addition of ferrous sulfate (MW/H₂O₂-AOP and MW/H₂O₂/Fe+²-AOP), were also studied for reducing solids, and solubilizing nutrients from the secondary sewage sludge. For the MW/H₂O₂/Fe+²-AOP, the best results of solubilization, in terms of orthophosphate, ammonia and soluble chemical oxygen demand, were obtained at treatment temperatures of 40 ºC, the yields decreased as the temperature was increased. The highest yields of solubilization were obtained at 60 ºC for orthophosphate, and at 80 ºC for both ammonia and soluble chemical oxygen demand.
130

Studies of magnetic effects of ICl

Stalder, Arnold Frederick 05 1900 (has links)
No description available.

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