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 16 of 16 for “"Surface resistance"”.
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A new surface resistance measurement method with ultrahigh sensitivity
… been designed and fabricated to study residual surface resistance of planar superconducting materials. Unlike many other structures where the test samples are placed in strong magnetic field positions, the edge of a 25.4 mm or larger diameter sample in the triaxial cavity is located outside the …
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Surface Resistance Measurements of Superconducting Niobium Samples with a Triaxial Cavity
… issues that affect accurate measurement of the surface resistance for small samples consisting of superconducting niobium films on copper substrates. It is believed that this work provides the groundwork for future research directed towards solving this important problem. Accurate measurement of …
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Study of nonlinear microwave properties of high-temperature superconducting film
… effect of patterning on the nonlinear microwave surface resistance of HTS films was studied by comparing the results of a dielectric-resonator technique and a stripline-resonator technique. We have concluded that patterning process contributes to neither the low-power surface resistance nor the …
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Nonlinear Dynamics of Vortices in Different Types of Grain Boundaries
… and their contribution to the residual surface resistance have not been well understood. To evaluate how GBs can limit the performance of SRF materials, particularly Nb and Nb3Sn, we performed extensive numerical simulations of nonlinear dynamics of Josephson vortices in grain boundaries …
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Numerical Calculation of Losses of Trapped Vortices Under Strong RF Meissner Current and DC Superheating Field in Type II Superconductors
… field of a superconductor with a nanostructured surface has not been well understood. We calculated the superheating field H<em><sub>sh</sub></em> and critical momentum kc characterizing the wavelength of the instability λ<em><sub>m</sub></em> of the Meissner state to flux penetration by solving …
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Advanced Characterization of Materials for Superconducting Radiofrequency Accelerator Cavities
… perspective this means reducing residual surface resistance or raising the operating temperature (currently ~2 K) of SRF cavities. Both are pursued by materials modification: nitrogen doping/infusion in the first instance and coating with Nb3Sn in the second. Materials characterization is …
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Studies of water vapor transport and sorption in wood
… the effect of different disturbances (e.g. the surface resistance) on the normally used methods of evaluating sorption measurements is presented. 5. In this paper problems concerning measurements of surface mass transfer coefficients are discussed. 6. A discussion of how non-Fickian behavior in …
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Electroding Methods for in situ Reverse Osmosis Sensors
… involves chemically modifying the RO membrane surface to facilitate platinization based on the hypothesis that deposition of foulant on the platinized surface will affect platinum/foulant/solution interfacial regions, thus sensor impedance. Platinized polymer graft sensors were shown to be …
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Experiential embodiment and human immediacy: Adorno’s negative affinity
… parts. These experiential structures present a surface, resistance, or solidarity that upon closer examination dissolve back into the ephemeral. Although such structures are profligate and prolific, the thesis adopts as its major concern artworks and aesthetics. Following Adorno, a claim is made …
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Investigation of the Superconducting Properties of Niobium Radio-Frequency Cavities
… characterized by a marked increase of the surface resistance at high rf fields, in absence of field emission. A low temperature "in-situ" baking under ultra-high vacuum has been successfully applied by several laboratories to reduce those losses and improve the cavity's quality factor. …
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An Investigation into the Seismic Resilience of Shallow Cut-and-Cover Tunnel in Urban Environments
… urban areas, where interactions with adjacent surface structures further complicate this dynamic soil-structure interaction (SSI). This dissertation presents a comprehensive investigation combining dynamic centrifuge tests conducted at the Schofield Centre of the University of Cambridge, and …
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Effects of anisotropy of the superconducting energy gap
… nuclear spin-lattice re1axati9n time, tunneling, surface resistance, and longitudinal ultrasonic attenuation are more sensitive to the details of the anisotropy than are the above thermodynamic properties. Theoretical expressions which explicitly include the anisotropy of a general gap parameter …
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MICROWAVE STUDY OF THE PROPERTIES OF UNCONVENTIONAL SUPERCONDUCTING SYSTEMS
… depth of bulk crystals and thin films, residual resistance of superconducting radio-frequency cavity systems for use in particle accelerators, and resonance properties of superconducting microwave electronic circuit components such as coplanar waveguides and Josephson junction devices. In recent …
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MATERIALS CHARACTERIZATION FOR SUB-MICRON SUPERCONDUCTING INTERCONNECTS IN RECIPROCAL QUANTUM LOGIC CIRCUITS
… the theoretical lower limit of intrinsic surface resistance $R_s = 17 \: \mu \Omega$ at 4.2 K and 10 GHz. The superior RIE process may be linked to the incorporation of thin metal passivation layers protecting the Nb, which prevented Nb oxide from participating in additional loss …
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Stealth technologies based on thin microwave FSS absorbers
… backed resistively loaded Frequency Selective Surfaces (FSS). <br/><br/>The deployment of ultra-thin (≤ λ/17) microwave FSS absorbers is proposed as a means to reduce the scattering of electromagnetic energy from the surface of satellite platforms which are covered with thermal blankets. This …
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Biosphere-Atmosphere Exchange of Peroxyacetyl Nitrate: Development of a Flux Measurement System and its Application on a Grassland Ecosystem
… mixing ratio differences. Due to both a higher surface resistance and larger uncertainties of the PAN analysis, at the natural grassland site no significant PAN fluxes could be resolved with the HREA method. The thesis demonstrates that above low vegetation, like the studied grassland, the MBR …