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 28 for “"Single-Atoms"”.
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Circles: Quantum Dots and Single Atoms
L'abstract è presente nell'allegato / the abstract is in the attachment
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Structural and Kinetic Study of Low-temperature Oxidation Reactions on Noble Metal Single Atoms and Subnanometer Clusters
… make the best utilization of noble metal atoms. Recent advances in nanotechnology have brought many attentions into the rational design of catalysts in the nanometer and subnanometer region. Recent studies showed that catalysts in the subnanometer regime could have extraordinary activity …
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Reconstruction of Rhodium Clusters During CO Oxidation and Consequences on The Reaction Mechanism
… metal nanoparticles, clusters and isolated (single) atoms. Understanding structure sensitivity and identifying the active site or sites are crucially essential for designing efficient catalysts. To determine the active sites of a catalyst for a particular chemical reaction, in-situ/operando …
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Optimizing Iridium Single Atom and Small Cluster Catalysts for CO Oxidation
Single atom catalysis is a relatively new form of heterogeneous catalysis. While single atom catalysts probably are already used in a lot of catalysis, their identification and characterization has only recently become common place. As we now have the ability to synthesis relatively pure systems …
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Structure Sensitivity in the Subnanometer Regime on Pt and Pd Supported Catalysts
Single-atom and cluster catalysts have been receiving significant interest due to not only their capability to approach the limit of atom efficiency but also to explore fundamentally unique properties. Supported Pt-group single atoms and clusters catalysts in the subnanometer size regime maximize …
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Uptake and Reaction Mechanisms of CO, H2O, and the Nerve Agent Simulant, DMMP with Single Atom-Modified Zirconium-based Metal-Organic Frameworks
… improve the protective capabilities of Zr-MOFs, single atoms of various transition metals have been deposited at the Zr-based nodes for prevention of irreversible binding of degradation products, based on previous computational studies that suggest single atoms form weaker, monodentate bonds to …
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Structure Sensitivity of Alkanes Hydrogenolysis and Alkynes Hydrogenation on Supported Ir Catalysts
… Ir particle size further increases and the Ir single atoms might be inactive for hydrogenolysis after the post-reaction analysis. The selectivity of n-butane hydrogenolysis is dominated by central and one terminal C–C bond cleavage on the n-butane molecules at low temperature range. The …
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Techniques for engineering quantum states
… theoretically study quantum states of ultracold atoms. The majority of the Chapters focus on engineering specific quantum states of single atoms with high fidelity in experimentally realistic systems. In the sixth Chapter, I investigate the stability and dynamics of new multidimensional solitonic …
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Structure-Sensitivity of CO Oxidation Over Supported Pt Catalysts in the Subnanometer Regime and Its Origin
… and its origin. We varied the Pt nuclearity from single-atoms to subnanometer clusters (0.8-0.9 nm) to small nanoparticles (1.5-1.8 nm). By coupling density functional theory calculations and microkinetic modeling with kinetic measurements, in situ/operando infrared and X-ray absorption …
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Untersuchung von Photonenzahlzustaenden mit dem Ein-Atom-Maser
… apparatus, which examines the interaction of single atoms of a weak thermal atomic beam with a single mode of a microwave resonator with a quality factor of 4 discussed in this thesis, shows how such a deterministic source for single photons can be realized in a pulsed one-atom-maser …
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Structure sensitivity of H2/D2 Isotopic Exchange on Pt/Al2O3 catalysts
… while increasing the particle size from single atoms (SA) to sub-nanoclusters to nanoparticles (NP), attributing the cause of these differences on activities to the activity of H2 activation in the H/D isotopic exchange reaction. In this work, the kinetics of H2 is studied by performing …
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Exploring Strategies to Break Adsorption-Energy Scaling Relations in Catalytic CO Oxidation
… effective way to break the scaling constraint is single atom catalysis. Strong interactions of supported single atoms with supports dramatically affect the electronic structure of active sites, which reroutes mechanistic pathways of surface reactions. In my PhD research, we use CO oxidation …
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Quantum Gas Microscopy of Bosonic Correlations in the Continuum
… quantum gas microscope for ultracold 87Rb atoms. Quantum gas microscopes enable site-resolved imaging, providing unprecedented access to quantum statistical effects and many-body phenomena. While such instruments are often employed to study physics in optical lattices, we have innovatively …
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Atomic-level Insights Into Atomically Dispersed Metal Catalysts
… type of atomically dispersed metal catalysts, single-atom catalysts (SACs) have been extensively investigated with broad applications. However, rational design of improved SACs for targeted chemistry faces tremendous challenges, largely due to lack of atomic-level understanding into the site …
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A Cavity-Coupled Rydberg Atom Array for Quantum Science and Quantum Computing
… boasting scalable, configurable arrays of single atoms trapped in optical tweezers, fast, high-fidelity entangling gates through Rydberg interactions, and programmable, parallelized control of qubit operations. Coupling an atom array to an optical cavity opens a new frontier. Leveraging …
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Investigations of hexagonal boron nitride: bulk crystals and atomically-thin two dimensional layers
… applications benefit from high quality, single crystals, with thicknesses varying from nanometers to microns. This research was undertaken to investigate four aspects of hBN crystal growth and recovery. (1) In an effort to optimize hBN crystal growth from a nickel-chromium flux, a series …
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Surface diffusion processes critical to metallic film nucleation and growth: An atomic view
… metallic thin films. Diffusion behavior of (1) single adatoms on a flat surface, (2) single adatoms near and at steps on a vicinal surface, and (3) small adatom cluster migration on terraces and (4) single vacancies on a flat surface has been investigated. Many important results have been found. …
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Towards synthetic Rydberg lattices with optical tweezer arrays
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-04-06 without embargo terms
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State-selective imaging of single rubidium atoms in a solid neon matrix
The development of single-spin quantum sensors with nanoscale resolution would provide immense utility in the determination of molecular structure, with applications in fields such as biology and chemistry. This dissertation discusses our progress toward using rubidium atoms trapped in solid neon …
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An atom trap trace analysis (ATTA) system for measuring ultra-low contamination by krypton in xenon dark matter detectors
… cooling and trapping techniques, and counts single trapped atoms. Since the isotopic abundance of 85Kr in nature is 1.5 × 10^-11, the 85Kr/Xe level is expected to be ~10^-23, which is beyond the capability of our method. Thus we detect the most abundant (57%) isotope 84Kr, and infer the 85Kr …
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