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 35 for “"D-band"”.
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Subband Stitching for D-Band Measurements
… the feasibility of lesser used high-frequency bands for the deployment of future systems. As part of this research, channel measurement campaigns are being conducted to characterize the channel over wide ranges of frequencies. In this thesis, we explore how a technique known as subband …
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Channel Sounding for D-Band Measurements
… interest is exploring the terahertz frequency band for communication potential in 6G. However, numerous channel sounding measurements must be collected to properly support channel models for this region. The work detailed in this thesis aims to address this current research areas, with three …
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Glass Based Packaging for Beyond 5G Communication
… of RF front-end (RFFE) modules in the D-band (110 GHz to 170 GHz) for next-generation wireless communication (6G). The focus is on heterogeneous integration solutions for 140 GHz CMOS IC and Indium Phosphide (InP) power amplifier (PA) RFFE modules, demonstrating the superior performance …
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Molecular oxygen adsorbates at a Au/Ni(111) surface alloy and their role in catalytic CO oxidation at 70 - 250 K
… and arises from poorer overlap between the Ni d-band and the 02 LUMO as the Ni d-band shifts to lower energy with increasing Au content of the Au/Ni surface alloy. The amount of molecular adsorption as a function of Au coverage cannot be described by an analytical or simulated model based on Au …
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Adsorption of oxygen molecules on platinum surfaces modified with subsurface atoms of vanadium : a DFT study
… for O2 adsorption. The first moment of the d-band of platinum alloy DOS was used to represent the d-band centre. The d-band centre of Pt-PDOS became lower as a result of hybridisation between platinum and vanadium. The d-band centre of a pure platinum surface with respect to the Fermi level is …
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Computational and Data-Driven Design of Perturbed Metal Sites for Catalytic Transformations
… metal alloys, including a physics model of d-band center, and a tight-binding theory of d-band moments to systematically elucidate the distinct electronic structures of novel catalysts. Within this framework, the hybridization of semi-empirical theories with graph neural network and …
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Plasmonic hot carrier-driven electrochemistry
… efficiently driven by athermal holes in the d-band, rather than less energetic holes in the sp-band. Nanorods exhibited reactive hot-spots for d-band holes at the tips. To expand plasmon driven chemical reactions to other materials that allow more tunability of optical and electronic …
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Measuring the Electronic Structure of Atomically Uniform Silver Films Grown on Silicon Using Angle-Resolved Photoemission Spectroscopy
… electronic structure evolves to form the bulk band continuum plus separates surfaces states. A careful analysis of this evolution allows us to separate surface from bulk effects, an important and troubling problem in photoemission spectroscopy. As a result, we are able to clearly identify, for …
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Understanding and controlling the reactivity of oxygen reduction and methanol oxidation electrocatalysts
… 4 investigates a novel approach to tune the d-band center and enhance the oxygen reduction reaction (ORR) activity of Pt material without relying on foreign metals or the process of alloying/dealloying. It is known that Pt exhibits suboptimal ORR catalytic activity due to its strong binding to …
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Millimeter-Wave and Sub-Terahertz Parametric Harmonic Generation
… circuits in millimeter-wave and sub-THz bands. A frequency tripler is designed in the 28-GHz 5G band, using the topology of symmetric antiparallel pair of series varactors to achieve about 24-dB conversion loss (CL), −8-dBm maximum output power (POUT), and 18% relative bandwidth (BW). Two …
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Gold-nickel surface alloy chemistry with oxygen and carbon monoxide
… for O₂ and CO that account for the alloy d-band, the surface atom centers' moiré pattern arrangement, and the associated subsurface reconstruction with triangular misfit dislocation loops. Surface alloying with Au is central to the existence and stability of peroxo- and/or superoxo-like …
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Pressure dependence of superconductivity in amorphous Ni x Zr 100-x alloys
… that s-d hybridization nature of the d-band (Nil plays a central role in the sign reversal behaviour. Application of pressures greater than 2 G Pa to Ni20ZrgO led to the formation of a new phase, w-Zr. which retains its form after the pressure is released.
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High oxygen permeation rates through poly(dimethyl siloxane) for fuel cells and oxygen reduction reaction mechanistic studies
… is correlated to related properties such as d-band center, and metal-oxide binding energy and bond distances. These properties are observable through XAS. XAS at lower energies, X-ray absorption near edge spectroscopy (XANES) can define d-band occupancy changes, related to oxidation states of …
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Pt and Pt-Pd cluster interaction with graphene and TiO₂ based supports: A DFT study
… cluster. This is due to different shifts in d-band centre of the facets on the cluster supported on these supports. Therefore, it can be expected that the Pt₃₈ cluster supported on OH functionalised graphene will be more tolerant to poison molecules. This is due to reduced binding strength of …
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Design, fabrication and characterization of sub-THz components in glass interposer substrates
… frequencies above 100 GHz to provide multi-GHz bandwidth necessary to support data rates in the order of 10 Gbps. Glass interposer technology is gaining attention for supporting these sub-THz modules because of its unique ability to support fine features sizes at low cost with superior …
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Preparation and characterisation of Pt/C and Ni/C modified electrocatalysts for use towards the oxygen reduction reaction for proton exchange membrane fuel cells
… has two consequences: (a) decrease of the Pt d-band centre and (b) change of the arrangement of the Pt and Ni atoms at the surface of the particles. The decrease in the Pt d-band centre resulted in the lowering of the adsorption strength of the oxide species which in turn led to a lower Pt-O …
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Electronic instabilities and the Martensitic transition in A-15 compouns
… temperature. Next, a tight binding, two (3-D) band model of the A-15 compounds, using delta 1 (x2-y2) d-orbitals has been formulated, on the basis of Mattheiss' APW-LCAO band calculations, and with essentially one adjustable parameter, a calculation done of the magnetic susceptibility, …
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Length dependence of the Raman spectra of carbon nanotubes
… the length sorted nanotubes. Specifically, the G-band (which includes the G+ and G- peaks), D-band, G', G*, and RBM Raman features were examined. We have found that the spectra fall into two categories: spectra with a narrow G& peak, and spectra with a broad and asymmetric Gpeak which is commonly …
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Some reactions of methylsilane catalysed by metals
… to the presence of the nominally filled d-band in gold.
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Photochemical studies of single-walled carbon nanotube ozonides and alpha-azoxy ketones
… small quantities of ozone did not result in a D-band increase in the Raman spectra, both for solid and liquid state experiments, though substantial decrease of the G band was observed. IR absorbance kinetics of SWNT films revealed exponential intensity drift over time with rates close to those in …
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