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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.
171

High-Performance 50μm Silicon-Based On-Chip Antenna with High Port-To-Port Isolation Implemented by Metamaterial and SIW Concepts for THz Integrated Systems

Alibakhshikenari, M., Virdee, B.S., See, C.H., Abd-Alhameed, Raed, Falcone, F., Limiti, E. 16 September 2019 (has links)
Yes / A novel 50μm Silicon-based on-chip antenna is presented that combines metamaterial (MTM) and substrate integrated waveguide (SIW) technologies for integration in THz circuits operating from 0.28 to 0.30 THz. The antenna structure comprises a square patch antenna implemented on a Silicon substrate with a ground-plane. Embedded diagonally in the patch are two T-shaped slots and the edges of the patch is short-circuited to the ground-plane with metal vias, which convert the structure into a substrate integrated waveguide. This structure reduces loss resulting from surface waves and Silicon dielectric substrate. The modes in the structure can be excited through two coaxial ports connected to the patch from the underside of the Silicon substrate. The proposed antenna structure is essentially transformed to exhibit metamaterial properties by realizing two T-shaped slots, which enlarges the effective aperture area of the miniature antenna and significantly enhances its impedance bandwidth and radiation characteristics between 0.28 THz to 0.3 THz. It has an average gain and efficiency of 4.5dBi and 65%, respectively. In addition, it is a self-isolated structure with high isolation of better than 30dB between the two ports. The on-chip antenna has dimensions of 800×800×60 μm3. / H2020-MSCA-ITN-2016 SECRET-722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E0/22936/1
172

The Processing and Evaluation of Long Lived GaA1As Channeled Substrate Planar Lasers

Look, Christopher 09 1900 (has links)
Part B of two parts. Part A found at: http://hdl.handle.net/11375/18724 / <p> The theory of operation and advantages of a channeled substrate planar (CSP) laser is described. The processing of such devices utilizing 5 N m wide proton bombardment defined current stripes is detailed. The optical and electrical characteristics of the resultant devices is presented. The lasers had pulsed, room temperature thresholds averaging 90mA, lased predominantly in a single longitudinal mode and were kink-free to power levels in excess of 6mW. Accelerated aging yielded an "activation energy" for the degradation process of 0.7eV which allowed for a predicted useful lifetime of 5 x 10^4 hours for these lasers. </p> / Thesis / Master of Engineering (MEngr)
173

Bond strength of the interface between concrete substrate and overlay concrete containing fly ash exposed to high temperature

Behforouz, B., Tavakoli, D., Gharghani, M., Ahsraf, Ashour F. 25 October 2022 (has links)
Yes / Bond between substrate and overlay concretes is a key factor for the success of the repair method and significantly influences the structural performance of the repaired element. This study investigated the effect of fly ash and the surface preparation method on the bond strength of repaired concrete after exposure to high temperatures, that has not been comprehensively studied in the literature. For this purpose, overlay concretes containing 0, 5, 10, 15, and 20% fly ash as a replacement by weight of cement were cast on the original concrete surface prepared by four methods namely, as-cast, wire brushed, grooved and grooved-wire brushed. The bond strength of the interface between concrete substrate and overlay concrete was evaluated after exposure to 23, 200, 400, and 600oC temperatures for 1 hour. The results showed that partial replacement of cement by fly ash in the overlay concrete increased the bond strength of repaired concrete by up to 71%, depending on the amount of fly ash used, surface preparation method, and the temperature to which the sample was exposed. The maximum increase of bond strength was recorded for concrete containing 20% fly ash when the wire brushed preparation method was adopted at temperature of 200oC. However, surface preparation was the most influential parameter, achieving a bond strength gradual increase in order from as-cast, wire brushed, grooved to grooved-wire brushed methods. The results also showed that for most of the samples having similar surface preparation and the same percentage of fly ash, bond strength decreased with the increase of exposure to temperature; for example, for overlay concretes without fly ash, in as-cast and wire brushed surface preparation methods at temperatures of 400 and 600 oC, the bond strength has reached zero. On the other hand, for grooved and grooved-wire brushed surface preparation methods, the bond strength reduction was about 63%, when temperature increased from 23 to 600oC. / The full-text of this article will be released for public view at the end of the publisher embargo, 12 month from first publication.
174

SUBSTRATE SPECIFIC CONTRIBUTIONS OF THE PROTEIN SUBUNIT OF E.COLI RNASE P TO SUBSTRATE RECOGNITION AND CATALYSIS

SUN, LEI January 2008 (has links)
No description available.
175

Development and electrochemical characterization of a Pseudomonas aeruginosa-based pure culture microbial fuel cell

Wang, Hao 22 August 2011 (has links)
No description available.
176

Bacterial communities in a Northeast Ohio stream: effects of substrate size, environmental features and temporal changes

Santmire, Judith Ann 13 April 2005 (has links)
No description available.
177

Structure-function studies and polarity and charge as substrate determinants for the E. coli YidC

Soman, Raunak Jay 10 October 2014 (has links)
No description available.
178

Paleo Pompeii; Genesis and Preservation of an Upper Ordovician Mounded Hardground with a Diverse Encrusting Community

Paton, Timothy R. January 2017 (has links)
No description available.
179

Habitat Use and Community Structure of Unionid Mussels in Three Lake Erie Tributaries

Grabarkiewicz, Jeffrey D. 13 December 2012 (has links)
No description available.
180

NEW DEVELOPMENTS OF BIOTRICKLING FILTERS: EXPERIMENTS AND THEORIES

FANG, YUANXIANG 22 May 2002 (has links)
No description available.

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