Complex oxides show great potential for future devices as they offer functionalities beyond what can be delivered by conventional semiconductors. Among the complex oxides, the ABO$_{3}$ perovskite oxides are the most studied and engineered in the form of thin films and heterostructures. This thesis applies powerful synchrotron-based X-ray characterization tools,...
At the interface of two dissimilar entities, something novel can emerge. This idea has driven a vast amount of fruitful work on semiconductor interfaces, and given us the digital revolution. In the past decade, remarkable progress has been made in the synthesis and understanding of interfaces between oxides, opening up...
Technology has advanced rapidly, especially in the twenty-first century, influencing our day-to-day life on unprecedented levels. Most such advances in technology are closely linked to, and often driven by, the discovery and design of new materials. It follows that the discovery of new materials can not only improve existing technologies...
This dissertation examines growth of platinum nanoparticles from vapor deposition on SrTiO3 using a characterization approach that combines imaging techniques and X-ray methods. The primary suite of characterization probes includes atomic force microscopy (AFM), grazing-incidence small-angle X-ray scattering (GISAXS), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and X-ray absorption spectroscopy...
Background: Evidence supporting a bidirectional relationship between depression and recurrent cardiovascular disease (CVD) appears strong, but there remains a need to better characterize the role of depression in CVD risk and cardiovascular health (CVH) promotion, especially in the context of comorbid risk factors such as cigarette smoking. In the present...
Oxide surface structures play a key role in many technological processes, including catalysis, thin film growth, and layered structures, and a thorough understanding of surface structures and surface structure dynamics is required in order to better engineer materials systems for these processes. This research works towards understanding these fundamental principles...
In his Nobel lecture Herbert Kroemer famously stated that “The interface is the device”. While he made this statement in the context of semiconducting heterostructures, it has proven to be just as relevant for more complex materials, such as the transition metal oxides. In particular, the 2-D conducting gas that...
Social engagement, or shared attention between a child and caregiver, is a critical process for language and social development. Although previous EEG studies have investigated child social processing in closely controlled, experimental studies, no study has examined the interactive, reciprocal process of naturalistic social engagement. In my first paper, we...
Regulatory T (Treg) cells are required to control immune responses and maintain homeostasis, but are a significant barrier to antitumor immunity. Conversely, Treg instability, characterized by loss of the master transcription factor Foxp3 and acquisition of proinflammatory properties, can promote autoimmunity and/or facilitate more effective tumor immunity. A comprehensive understanding...
Halide perovskites, AMX3 (A = monocation, B = Ge, Sn, or Pb, and X = halogen), present a versatile class of solution-processable semiconductors made from earth abundant materials with outstanding electrical and optical properties. Their solar cell efficiencies have dramatically increased from ~9% to ~22% in less than five years...
The mechanisms governing selective CaCO3 crystal nucleation in living organisms remain unclear. For example, nacreous layers from the inner surfaces of shells are built as brick-and-mortar complexes of plate-like aragonite single crystals and organic layers. Unstable [001] surfaces of calcite columns in prismatic layers are also stabilized by organic molecules....
The scope of this thesis extends to the study of surface structures and electronic properties in a number of complex oxides. The c(6x2) surface reconstruction on SrTiO3 (001) was solved using a combination of plan view transmission electron microscopy imaging, atomic resolution secondary electron imaging, and density functional theory calculations....
Physiochemical phenomena in aqueous systems, such as corrosion, catalysis, and energy storage, are driven by the molecular-scale interactions of ionic species with charged solid surfaces. In particular, an electrical double layer (EDL) of ions forms within nanometers of a charged surface. The properties of the EDL have been explored from...
NiTi shape memory alloy (SMA) has drawn a great deal of attention for its various applications in the medical field (orthodontics, cardiovascular stents technology, etc.) and in other engineering fields (aerospace, aircraft, automotive, etc.) as it shows shape memory effect, superelasticity and biocompatibility. The fatigue-related issues, however, are pronounced in...
In this thesis we study minimal measures for Lagrangian systems on compact manifolds. This thesis consists of three parts which are closely related.
The first part is Chapter 3 and Chapter 4. In Chapter 3 and 4, we consider geodesic flows on compact surfaces with higher genus. We show that...
The idea of the unity of audition and vision has been a topic of interest since the time of ancient Greece. Investigation of this idea has continued to grow in many areas, especially in psychology, music, visual art, and computer science, most notably since the invention of the world's earliest...
The semiconductor-based Quantum Cascade Laser (QCL) offers several key advantages over gas lasers, solid-state lasers, and other semiconductor-based mid-infrared lasers. While the QCL has historically operated best in the λ ~ 7-9 μm range using InP-based materials, a major challenge has been to achieve a high-power, room-temperature continuous-wave (CW) operation...
The overall objective of this thesis is to develop a package of high-resolution, non-invasive experimental and numerical approaches to observe in situ pore-scale geometry modification due to colloid deposition, and quantitatively predict its effects on the large-scale transport properties of the porous medium. High-energy synchrotron-based X-ray difference micro-tomography (XDMT) was...
Funding risky Research and Development (R&D) and New Product Development (NPD) projects is crucial for the long term health of any large company. Such funding decisions are multiobjective and are undertaken with sparse data. Therefore prescriptive or algorithmic solutions are not adopted by practitioners. Descriptive solutions that provide managerial insights...
Visual object tracking, i.e. consistently inferring the motion of a desired target from image sequences, is a must-have component to bridge low-level image processing techniques and high-level video content analysis. This has been an active and fruitful research topic in the computer vision community for decades due to both its...