68 research outputs found
Dataset supporting: "Generative Image Restoration and Super-Resolution using Physics-Informed Synthetic Data for Scanning Tunneling Microscopy"
No full textThis upload contains the dataset used for the research paper:
Kolev, N. L., Rodani, T., Curson, N. J., Stock, T. J. Z., & Cazzaniga, A. (2025). Generative image restoration and super-resolution using physics-informed synthetic data for scanning tunneling microscopy (arXiv:2510.25921). arXiv. https://doi.org/10.48550/arXiv.2510.2592
Legend of Fenrir and other Nordic stories
No full textPublished work by a Douglas College Student. Exiled to Midgard, world of the humans, Fenrir searches for his lost sons. After the gods of Asgard banish his sons to Midgard, Fenrir escapes their grasps in order to find his sons and escape Odin's judgement. In a tale of isolation and defeat, Fenrir must push himself harder than he ever has if he wishes to see his sons again, for while he searches for his sons, the gods of Asgard search for him. Many obstacles separate Fenrir from his sons, yet Fenrir will fight against all who stand before him to save his sons. But will he stand victorious? Legend of Fenrir is an original work rooted within the world of Norse mythology. In this novel, Fenrir takes part in and witnesses some of the mythological tales that were told by our real world's Vikings. From publisher description.boo
Generative Image Restoration and Super-Resolution using Physics-Informed Synthetic Data for Scanning Tunneling Microscopy
No full textScanning tunnelling microscopy (STM) enables atomic-resolution imaging and
atom manipulation, but its utility is often limited by tip degradation and slow
serial data acquisition. Fabrication adds another layer of complexity since the
tip is often subjected to large voltages, which may alter the shape of its
apex, requiring it to be conditioned. Here, we propose a machine learning (ML)
approach for image repair and super-resolution to alleviate both challenges.
Using a dataset of only 36 pristine experimental images of Si(001):H, we
demonstrate that a physics-informed synthetic data generation pipeline can be
used to train several state-of-the-art flow-matching and diffusion models.
Quantitative evaluation with metrics such as the CLIP Maximum Mean Discrepancy
(CMMD) score and structural similarity demonstrates that our models are able to
effectively restore images and offer a two- to fourfold reduction in image
acquisition time by accurately reconstructing images from sparsely sampled
data. Our framework has the potential to significantly increase STM
experimental throughput by offering a route to reducing the frequency of
tip-conditioning procedures and to enhancing frame rates in existing high-speed
STM systems
Who is the impostor discover'd [electronic resource] : or, the vindication of John Curson, from the malicious aspersions in the Daily Post of the 3d instant.
No full textWith a half-title.Dated at end: April 1729.Price from imprint: price 6 d.Electronic reproduction.English Short Title Catalog,Reproduction of original from British Library
Toward atomic-scale doping of bismuth in silicon: the study of bismuth precursor molecules on silicon (100)
No full textSingle-atom dopants in silicon have been a topic of high interest since the Kane quantum computer was first proposed in 1998. Much work has since been dedicated toward the single-atom doping of lighter group 15 atoms into silicon with atomic-scale precision, with notable success, though significantly less toward heavier dopant atoms owing to the lack of readily available precursor molecules. This thesis investigates two novel potential precursor molecules for atomic bismuth: triphenylbismuth (TPB) and bismuth trichloride (BiCl3). Bismuth is a promising heavy dopant species in silicon-based electronic devices thanks to its high quantum information storage capacity, but currently lacks a suitable precursor. Neither of these molecules has previously been studied on the Si(100) surface.
Using scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), we demonstrate that TPB partially dissociates on Si(100) at room temperature, with bismuth atoms forming ad-dimers while phenyl remains on the surface. Annealing the surface causes complete molecular dissociation, followed by bismuth diffusion into the bulk. Phenyl desorption is not observed. We show that prior to dissociation, TPB bonds to the surface in a variety of configurations; using density functional theory calculations, we propose favorable bonding structures for the TPB molecule on Si(100).
We also show that BiCl3, contrastingly, undergoes complete and spontaneous dissociation on Si(100) at room temperature, with some bismuth atoms forming ad-dimers while others remain as monomers constrained by adjacent chlorine atoms. We pro- pose key steps in the reaction pathway for room-temperature BiCl3 dissociation. We also demonstrate the molecule’s post-dissociation chemical behavior on Si(100) at higher temperatures, at varying levels of surface coverage. Our results demonstrate that BiCl3 is a promising candidate for a single-atom bismuth precursor, while TPB is less likely to be suitable. In combination with chlorine lithography, this paves the way for single-atom doping of bismuth in silicon devices
Psychologically informed environments: A systematic review of qualitative studies of staff experiences and recalled early adversity and post traumatic stress disorder in a youth homeless population
No full textThis thesis is made up of two papers: a systematic review and an empirical study. The systematic review aimed to synthesise the evidence regarding staff experiences of Psychologically Informed Environments (PIEs), which is an initiative that aims to transform services for homeless people and enable service providers to engage them in a more psychologically informed way.
It is well documented that people who are homeless often have comorbid mental health difficulties, a higher rate of engagement with the criminal justice system and can display behaviours considered challenging, such as emotional dysregulation or the use of illicit substances. It is also recognised that working with this client group can have an emotional toll on staff members who are often exposed to stories of trauma and are expected to manage high risk behaviours. PIEs were introduced in 2012 as a more informal way of working with homeless people with the aim of improving the engagement of this hard-to-reach group, but there exists no current review of its effectiveness. This systematic review aimed to synthesise research regarding staff experiences of working in a PIE. Searches were conducted using the databases Scopus, Psycinfo, Web of Science and Medline, alongside additional searches of reference lists, Google Scholar and citation searches. Articles were screened and assessed for quality by the first author.
Nine papers were included in the review, consisting of both published research and service reports, which ranged in quality. As such little evidence exists on this topic, all papers were included in order to be as thorough as possible. Thematic synthesis allowed for new interpretations to be drawn from the collation of the data. Seven analytical themes were developed, and the findings were generally positive, though the barriers and challenges to implementing a PIE were identified as a key theme. The review synthesises the current evidence base for the use of PIEs, but the service user voice was noticeably absent from the analysis, as is a common shortcoming in research with the homeless population. More robust studies are needed in order to draw more conclusions regarding the effectiveness of PIEs.
The empirical paper is a quantitative study that aimed to explore the relationships between adverse childhood experiences (ACEs) and PTSD symptoms in a young homeless sample. This study used archival data and built upon research already resulting from the same dataset, which had noted high rates of loneliness and low rates of self-mastery among those in this sample who also scored highly on a measure of PTSD symptoms. A moderation analysis was conducted to explore whether these two variables were acting as a moderator on the relationship between ACEs and PTSD symptoms.
Statistical analyses showed that experiencing multiple types of adverse childhood adversity was a predictor of higher scores on the PTSD symptom measure, with each additional type of adversity showing a dose-response effect. An odds ratio analysis demonstrated that the experience of sexual abuse particularly increased the risk of meeting the clinical cut off score on the PTSD symptom measure. A hierarchical regression, where adversities were entered as sexual abuse, childhood maltreatment or household dysfunction, showed that sexual abuse had the greatest predictive effect, followed by household dysfunction, of scores on the PTSD symptom measure. Several categories of childhood adversities were correlated with self-mastery and PTSD symptoms. Of a larger dataset, only 84 participants had completed the PTSD symptom measure, which meant that the moderation analysis was underpowered, perhaps explaining why no significant effects were detected.
This study adds to the understanding of the effects of ACEs on young homeless people, especially in terms of identifying which types of abuse make young people particularly vulnerable to post-traumatic symptoms. This could be beneficial to third sector support services working with this population, in informing how they screen for different types of abuse and thus tailor psychological interventions
Topological phases of a dimerized Fermi-Hubbard model for semiconductor nano-lattices
No full textMotivated by recent advances in fabricating artificial lattices in semiconductors and their promise
for quantum simulation of topological materials, we study the one-dimensional dimerized Fermi-
Hubbard model. We show how the topological phases at half-filling can be characterized by a
reduced Zak phase defined based on the reduced density matrix of each spin subsystem. Signatures
of bulk-boundary correspondence are observed in the triplon excitation of the bulk and the edge
states of uncoupled spins at the boundaries. At quarter-filling we show that owing to the presence of
the Hubbard interaction the system can undergo a transition to the topological ground state of the
non-interacting Su-Schrieffer-Heeger model with the application of a moderate-strength external
magnetic field. We propose a robust experimental realization with a chain of dopant atoms in
silicon or gate-defined quantum dots in GaAs where the transition can be probed by measuring the
tunneling current through the many-body state of the chain
Bismuth trichloride as a molecular precursor for silicon doping
No full textDopant impurity species can be incorporated into the silicon (001) surface via the adsorption and dissociation of simple precursor molecules. Examples include phosphine (PH3), arsine (AsH3), and diborane (B2H6) for the incorporation of phosphorus, arsenic, and boron, respectively. Through exploitation of precursor surface chemistry, the spatial locations of these incorporated dopants can be controlled at the atomic scale via the patterning of a hydrogen lithographic resist layer using scanning tunneling microscopy (STM). There is strong interest in the spatial control of bismuth atoms incorporated into silicon for quantum technological applications; however, there is currently no known precursor for the incorporation of bismuth that is compatible with this STM-based lithographic method. Here, we explore the precursor chemistry (adsorption, diffusion, and dissociation) of bismuth trichloride (BiCl3) on Si(001). We show atomic-resolution STM images of BiCl3 exposed Si(001) surfaces at low coverage and combine this with density functional theory calculations to produce a model of the surface processes and the observed features. Our results show that, at room temperature, BiCl3 completely dissociates to produce bismuth ad-atoms, ad-dimers, and surface-bound chlorine, and we explain how BiCl3 is a strong candidate for a bismuth precursor compound compatible with lithographic patterning at the sub-nanometer scale
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