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The study of complex oxides through combinatorial efforts would require a prohibitive amount of material resources and time if experiments were conducted using bulk techniques and at macroscopic length scales. The work in this thesis details the application of leading-edge materials processing in conjunction with advanced micron-scale synchrotron characterization to enable high-throughput studies in the search for metastable materials. Lateral-gradient laser spike annealing is used to rapidly heat and quench millimeter scale samples of thin films of metal oxides. This technique generates a multitude of locations with specific processing histories in a single experiment that are assayed by optical microscopy, micron-scale reflectance spectroscopy, and micron-scale x-ray diffraction. These analytical techniques offer a hierarchy of information on the transformed thin film with a corresponding increase in complexity and accessibility (cost). It is shown how the spatially resolved techniques can be used to construct processing phase maps denoting important phase fields and transformation boundaries as a function of the processing time and temperature, analogous to the canonical time-temperature-transformation diagrams. Two optical methods are demonstrated as quantifiably relevant proxies for identifying crystallographic transformations as validated by x-ray diffraction. This is demonstrated by cross correlating and comparing observed transformations identified using the three analytical techniques as applied to amorphous thin films of Ga2O3 and a pseudo-binary composition spread of amorphous La2O3-Mn3O4, in both cases spanning a range of processing times and temperatures. Exploration of these material spaces is improved upon by incorporating artificial intelligence and machine learning methods with the development of SARA, the Scientific Autonomous Reasoning Agent. The first iteration of SARA aims to autonomously and rapidly construct these diagrams from readily available optical methods. This is achieved through the use of experimentally informed and intelligently designed Gaussian process regression models. The performance of this learning method is validated by comparison with an exhaustively explored phase map of the Bi2O3 system. Finally, a systematic study of the laser spike annealed transformations in amorphous SnO2 and amorphous Sn2O3 is conducted. Each film comprises regions capped with and without an Al2O3 oxygen passivation layer in an attempt to disentangle the competing non-equilibrium effects of laser spike annealing under atmospheric conditions and initial oxygen composition. Rapid phase identification and quantification algorithms applied to the spatially resolved x-ray diffraction data are validated in preparation for the next generation of autonomous experimentation, in which exploration and learning are derived from the underlying crystallographic information. There are transformations in both of these chemical systems that reveal the ability to produce metastable materials even in extensively explored and highly engineered systems. Notable are the retention of the litharge-type SnO compound, even when processing temperature exceeds the known decomposition temperature of the amorphous Sn2O3 film, and the observation of a previously unreported nucleating precursor phase from the amorphous SnO2 film.

This dissertation presents an assortment of research aimed at understanding the composition-dependence of deformation behavior and the response to thermomechanical processing, to enable efficient design and processing of low stacking fault energy (SFE) high entropy alloy (HEAs). The deformation behavior and SFE of four low SFE HEAs were predicted and experimentally verified using electron microscopy and in-situ neutron diffraction. A new approach of employing a minimization function to refine and improve the accuracy of a semi-empirically derived expression relating composition with SFE is demonstrated. Ultimately, by employing the minimization function, the average difference between experimental and predicted SFE was found to be 2.64 mJ m-2. Benchmarking with currently available approaches suggests that integrating minimization functions can substantially improve prediction accuracy and promote efficient HEA design with expansion of databases. Additionally, in-situ neutron diffraction was used to present the first in-situ measurement of the interspacing between stacking faults (SFs) which were correlated with work hardening behavior. Electron transparent specimens (< ~100 nm thick) were used in order to resolve nanoscale planar faults instead of the thicker sub-sized specimens (on the order of millimeters in thickness) which exhibit the classical stages III work hardening behavior characteristic of low SFE metals and alloys. The present study demonstrates these characteristic dimensions of SFs can be tracked in real-time using neutrons or high-energy x-rays. SFs have also been shown to act as barriers to dislocation motion and thus contribute to strengthening and sustained work hardening during deformation.

The interaction of plasmas with a liquid phase results into various complex multiphase phenomena that is beneficial for a wide range of applications, such as water treatment, nanoparticle synthesis, material processing, combustion, decontamination, food safety and human health care. These applications have been made possible due to the transferof highly reactive species from the gas phase plasma to the bulk liquid phase. Upon interaction with a liquid phase, atmospheric pressure non-equilibrium plasmas produce numerous chemically reactive species, including ions, radicals, electrons and (V)UV photons. The resulting short-lived highly reactive species can exhibit huge density gradients in the liquid phase as their finite lifetime does not allow them to penetrate into the bulk liquid. This makes the multiphase reactivity transfer highly transport limited. Additionally, the presence of electric field-induced effects, charging, evaporation and heat and mass transfer makes plasma-liquid interaction studies more challenging due to the lack of a detailed understanding of the inter-coupling of these phenomena and their direct impact on the plasma-produced reactive species fluxes to the liquid. To understand and overcome the challenge of transport limitations, a novel plasma-liquid configuration was developed, which involves plasma activation of small dispersed liquid droplets or aerosols. The key advantage of such a configuration is that the large surface-to-volume ratio of these micrometer-sized liquid droplets enhances the reactivity transfer from the gas phase plasma to the liquid phase. Since the droplets are immersed in the plasma, the short-lived reactive species (electrons, ions and radicals) produced in the gas phase plasma due to electron impact processes on average only need to cover smaller length scales to reach and subsequently penetrate the droplet. The foremost goal of the research reported in this thesis is the development of a controlled and well-defined plasma-microdroplet reactor, which is easy to model and experimentally accessible with different diagnostic techniques enabling to obtain quantitative measurements of reactive species densities. Due to the efficient generation of reactive species, a radiofrequency (RF)-driven capacitively coupled diffuse plasma generated in parallel-plate configuration at atmospheric pressure is used in this work. Complete characterization of the RF plasma is helpful for the assessment of the role of different gas-phase reactive species generated by the plasma and their respective fluxes to the liquid microdroplets in transit through the plasma. The reactive species potentially playing a key role in plasma-liquid interactions include electrons, OH radicals, H and O atoms, singlet oxygen, O3, He and Ar metastable atoms and molecules. The absolute densities of electrons and metastable atoms and molecules along with gas and electron temperatures that play a major role in plasma-induced chemistry in He and Ar plasmas were measured using optical emission and broadband absorption spectroscopy. We found that the densities of He and Ar metastables peaked near the sheath edges away from the droplet trajectory, while the densities in the bulk were below their respective detection limits. The Ar and He metastable fluxes to the droplet were found to be 2 orders of magnitude and 5 times smaller than the electron flux to droplet, respectively. Hence, the effect of Ar and He metastable atoms on the droplet chemistry can be considered negligible compared to charged species fluxes. However, these metastable species are an important source of ionization in such low electron density plasmas and play, nonetheless, a major role in the plasma dynamics including ionization processes and the generation of radicals in the gas phase. An understanding of the dynamics of liquid microdroplets in the plasma is important as it not only relays information about the residence time of the droplets in the plasma (i.e. treatment time of the solution by short-lived plasma-produced species) but also droplet charging and the presence of electric fields when entering and exiting the plasma. This residence time dictates the fate of the droplet chemistry and its interactions with the plasma. We characterized the droplet and its trajectory by fast frame imaging in diffuse He glow discharge. From the droplet velocity and acceleration data, the various forces acting on the droplet were evaluated. Using the equilibrium of forces and the droplet charge estimated from an analytical model, the electric field at the plasma edges was determined. We also report on the effect of the initial droplet acceleration during droplet ejection from the piezoelectric nozzle, the plasma composition (He with admixtures of Ar, H2O, H2 and O2), gas flow rate, and the plasma power on the droplet dynamics. Plasmas in or in contact with water have been extensively investigated in the context of plasma-aided decomposition and mineralization of recalcitrant organic pollutants in water for environmental remediation. However, plasma, while being highly effective, sometimes lacks energy efficiency. The water treatment is often due to the transfer of long-lived species into the liquid bulk and secondary reactions. Using the approach of microdroplets treated by plasma, the efficiency of plasma treatment of organics in liquid water microdroplets can be improved by increasing the species fluxes to the droplets. Using detailed plasma diagnostics, droplet characterization and ex situ chemical analysis of the treated droplets, we assessed the relative importance of short-lived radicals, such as O and H atoms, singlet oxygen, solvated electrons and ions, besides OH radicals, responsible for the decomposition of formate, a model organic compound inwater treatment studies, dissolved in droplets. We ascertained the role of OH and O radicals in electronegative plasmas. We also showed for electropositive plasmas that solvated electrons and/or ions injected into the droplet were dominantly responsible for plasma-induced chemistry in the droplet. Results suggested that the charged species lead to the formation of H or OH radicals near the droplet interface via secondary reactions, enabling further decomposition of formate in the droplets. The obtained results allowed us to estimate minimum values of transport properties of O in solution and reaction rates of O radical with formate using a one-dimensional reaction-diffusion model. Gold and silver nanoparticles (AuNP and AgNP) exhibit unique optical, electrical, and thermal properties, and can be synthesized by plasmas in a green and environmentally friendly approach without the use of hazardous chemicals, and without producing harmful byproducts. Previously, researchers have established unprecedented gold ions reduction synthesis rates in liquid droplets treated by an RF plasma to synthesize AuNPs. The reported reduction rates are several orders of magnitude larger than for any other reported electron-initiated methods. The mechanism for the synthesis of nanoparticles using this approach is still largely unknown. Using the known gas-phase plasma properties, absorption spectroscopy, and transmission electron microscopy (TEM), we identified the role of hydrogen peroxide in the reduction of gold ions. On the other hand, the reported results for AgNP formation from Ag ions in the same reactor, suggested that the effect of solvated electrons and H radicals were dominant for the reduction of silver ions. We also demonstrate the possibility to use plasma-droplet interactions for the synthesis of surfactant-free, spherical and crystalline Au and AgNPs without the use of any stabilizer(s) within a few milliseconds. In view of the recent COVID-19 pandemic caused by the airborne transmission of SARS-CoV-2 virus aerosols, many excellent surveillance and control measures are being implemented in conned spaces, where the effect of the virus transmission is the highest. The application of plasma-aided virus disinfection is quite nascent, and the interaction of plasma with the virus aerosols in air streams has not been dealt with in detail. The actual mechanism for the virus inactivation is often ascribed to ozone, however, in short time scales of milliseconds, more reactive species might be needed to obtain an effective inactivation. We report on the use of a dielectric barrier discharge (DBD) for in-flight inactivation of airborne aerosolized porcine reproductive and respiratory syndrome (PRRS) virus. The measurements were performed in a laboratory-scale wind test tunnel. Using infectivity tests and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), we showed a 3.5 log10 reduction in the viable virus titer during in-flight treatment by the DBD within a few milliseconds. We identified both short-lived species such as OH radicals and singlet oxygen and peroxynitrous acid chemistry at low pH in the virus-laden droplets responsible for the observed inactivation of virus aerosols by plasma. The fundamental understanding of the interactions of plasma and liquid microdroplets, gained in this work, have the potential to increase significantly the efficacy of plasma processes. There is no doubt that improved reactor design and plasma generation informed by our findings will further advance the development of such unique interactions for the novel applications of water treatment, nanoparticle synthesis and virus aerosol inactivation.

Predicting events in metastable systems is an important but challenging problem. It can help society forecast, prevent, or prepare for upcoming catastrophes. However, many metastable systems in nature operate near a critical point and are empirically unpredictable. We developed machine learning predictors, applied them to the prediction of nucleation events in the metastable Ising model, near and far from the spinodal critical point. We observed decreasing predictability as the critical point is approached, and found that this unpredictability is due to the vanishing density difference between the nucleating droplet and the background. We also developed a tensor representation of Lennard-Jones con gurations using the symmetry order parameters of the particles and use this representation to predict nucleation in a dense Lennard Jones liquid. Finally, we investigated the noise-induced critical point in two variations of the OFC model - a coupled OFC model and a OFC model with multiplicative noise. In both variations, we found a critical phase boundary that separates the ergodic and non-ergodic phase and the termination point of the phase boundary, which is consistent with a higher-order phase transition.

The highly popular ytterbium-171 ($^{171} \mathrm{Yb}^+$) ion is commonly employed in quantum information research as a qubit whose excellent coherence time and fast, simple state preparation has allowed cutting edge work in quantum computation and simulation. Despite these large benefits, the demonstrated measurement fidelity of this ion has lagged the state preparation and gate fidelity achieved to date.In this thesis we investigate and realize methods of increasing the measurement fidelity of $^{171} \mathrm{Yb}^+$ in a scaleable way for large quantum systems. Using methods of coherent control, we implement a pulsed state detection scheme using a mode-locked laser to perform background-free spectroscopy of the ``bright'' state of the qubit. The small hyperfine splitting of the ion necessitates the use of multiple (two) pulses to manipulate time dynamics of the ion to excite a single transition. A Mach-Zehnder interferometer is constructed to control these pulse separations both coarsely ($\sim$ 237 ps) and on a fine sub-femtosecond scale. These pulses cause destructive/constructive interference of the electron wave packet of a single ion levitated in vacuum and are engineered to state-selectively excite the qubit. This allows measurement of the qubit whose transition frequency is much smaller than the bandwidth of the interrogation laser.During this spectroscopy, mechanical forces from the mode-locked laser frequency comb can drive the ion into large coherent states of motion. This motion has been dubbed ``phonon lasing''. We investigate the phonon lasing affect and how the ion interacts with multiple comb teeth. The large number of teeth leads to a protection mechanism from runaway energy gain by near-by blue detuned teeth, allowing ions to be trapped and cooled by the mode-locked laser, regardless of its detuning. We further explore these discrete amplitude coherent states by injecting energy into the ion's motion and exciting higher-order oscillations.We, for the first time, implement an ``electron shelving'' of the hyperfine qubit, and incoherently transfer the bright state population in the extremely long-lived ($\approx$5 yr) $^2$F$_{7/2}$ state of $^{171}$Yb$^+$, functionally disconnected state. This is accomplished via narrow-band optical pumping on the $^2$S$_{1/2}$ to the $^2$D$_{5/2}$ quadrupole which has a leaky dipole channel into the $^2$F$_{7/2}$. Narrow-band optical pumping is again used to rescue the ion at the end of the experiment with the aid of a 760 nm E2 transition back into the cooling cycle. Measurement with this scheme is no longer limited by off-resonant effects from the main cycling transition. Limits of this novel technique, as well as further directions using the F state as a utility for quantum information are explored. Finally, we combine the pulsed background-free spectroscopy with shelving and demonstrate high-fidelity, background free detection of a single trapped $^{171}\mathrm{Yb}^+$ qubit.

A seizure emergency occurs when an individual experiences a seizure that lasts for more than five minutes (status epilepticus) or multiple distinct seizures with incomplete recovery between them (acute repetitive seizures). A patient experiencing a seizure emergency must be treated as quickly as possible to avoid lasting neurological damage and other life-threatening complications. Benzodiazepines are the primary rescue medications used to treat seizure emergencies, the most commonly used being intravenous lorazepam or rectal diazepam. Despite the effectiveness of these drugs, the delivery routes are not ideal for first-line, outpatient treatments. A skilled caregiver must be present to administer drugs intravenously, and the social stigma associated with rectal administration results in low compliance. Intranasal delivery is an attractive alternative because it requires little training, is easily performed by non-medical personnel, carries a low risk of injury to the patient, and can provide a rapid therapeutic effect. However, formulating a benzodiazepine nasal spray is challenging because these drugs have very low aqueous solubilities. One strategy to circumvent solubility issues relies on in situ production of drug from co-administration of soluble reactants. Herein, we describe how a prodrug/enzyme reaction or an acid/base reaction can be used to deliver a benzodiazepine in an aqueous vehicle with a volume and pH appropriate for intranasal administration. When the soluble components of these two-part reactive formulations are mixed at the time of administration, a metastable supersaturated solution of the benzodiazepine is produced. The supersaturated state of the benzodiazepine provides a large chemical activity gradient for rapid absorption across the nasal mucosa and into systemic circulation. In vitro characterization of the reaction kinetics and supersaturation behaviors for diazepam prodrug/enzyme reactions, midazolam prodrug/enzyme reactions, and midazolam acid/base reactions demonstrated that these two-part formulations generate predictable levels of supersaturated drug. An in vivo pharmacokinetic study in rats showed that rapid absorption and high bioavailability of diazepam results from intranasal administration of a diazepam prodrug/enzyme formulation. Furthermore, a dual chamber nasal spray device capable of mixing and atomizing the components of a two-part formulation was designed, prototyped, and tested. These two-part reactive formulations, coupled with the specialized nasal spray device, exemplify a new intranasal drug delivery strategy that may be applicable to a variety of other drugs with poor stability or low solubility.

To understand and predict phenomena in solid materials, we often look at how the lattice structure brings about such an effect. Our lab analyzes the extended x-ray absorption fine structure (EXAFS) to closely study the physical configuration of atoms in a lattice. I will talk about the interesting local structure of the following compounds: Organic lead-halide perovskites MAPbI3 andMAPbBr3, ytterbium doped calcium fluorite (CaF2:Yb), and lithium niobate doped with Zn,Er,In, and Hf.Organic perovskites have been a material of high interest for harvesting light. In order to improve crystallization of solution based methylammonium lead iodide (MAPbI3), we aim to maximize lead-iodide coordination via an excess of iodide precursors: methylammonium iodide (MAI) and hydrodic acid (HI). We find that a surplus of HI results in higher order and coordination for the nearest Pb–I atomic shell (six iodine neighbors). In another study, we look into the disorder and vibrational properties of MAPbBr3 in different structural phases. This dissertation includes a temperature dependent study on the local structure of MAPbBr3, and a rigorous quantifying of the anharmonicity parameter, C3, that represents dynamic disorder. C3 increases nonlinearly with temperature and results in an asymmetric pair distribution for the nearest Pb–Br shell.Calcium fluorite doped with ytterbium is a doped simple FCC crystal with a down-shifted anomalous luminescence. A long lived excited state decays with a yellow-green emission and can be induced with UV exposure. With two consistent methods quantifying amount of Yb in the 2+ and 3+ state, we present compelling evidence that the impurity trapped exciton model does not explain this system. Further, we can elucidate the various metastable states of this system and their relation to strange observations.Finally, lithium niobate has piqued interest in frequency conversion device engineering as a non-linear optical material. There lacks a general model for how the photorefraction is affected by different species of dopants, but there are proposed charge compensating substitution schema. We judge models of substitution schema based on solution energy calculations using our EXAFS results of lithium niobate doped with zinc, indium, erbium, and hafnium.

For the past 50 years, the electronics industry has profited from their ability to follow Moore’s Law, doubling the performance of the computer chip approximately every two years. Traditionally, these improvements came from reducing the size of the logic switches, or transistors, so that more could fit in a given sized computer chip. However, the electronics industry has hit a roadblock where merely shrinking components no longer improves the performance. To overcome this hurdle, manufacturers are beginning to implement non-traditional device structures and materials into computer chips. Compound semiconductors are strong candidates for materials to replace silicon based on their improved speed and efficiency with, importantly, lower power requirements. III-V materials, like InGaAs and InAs, are promising candidates to replace silicon in areas in the transistor that require high conductivity semiconductors. Low-power device architectures can be realized with GaN and other III-N materials. Although charge-carrying electrons can move much faster in these materials, a fundamental issue is getting enough free electrons into the materials through a process called doping, hence limiting the conductivity that can be achieved. This is the problem that my work addresses-- studying how fast thermal processing could improve the electrical properties of doped III-V and III-N materials. Using sub-millisecond to millisecond laser spike annealing (LSA), we can transiently reach high annealing temperatures, and, in this way, improve conductivity by achieving high active concentrations of dopants in these materials. We have broadly characterized LSA for III-V and III-N materials with a high-throughput, combinatorial processing method. With this method, we explored kinetically limited states that are inaccessible using typical heating approaches like furnace and rapid thermal annealing (RTA). We found that LSA increased the activation of high-dose implanted dopants in InGaAs to a peak concentration beyond a previously established thermodynamic limit, improving dopant activation by a highly significant 29%. In contrast to longer timescale anneals (like those from furnace anneals or RTA), no deactivation is observed during LSA processing for InGaAs samples with dopants grown in to active positions. Our latest LSA studies of implanted GaN resulted in achieving nearly 100% activation of dopants. In these millisecond time frames, LSA is effective for ion-implantation dopant activation and for retention of metastable as-grown dopant concentrations. Our work shows that this kind of metastable processing will be critical to future device applications that use III-V and III-N materials.

The Hsp90 molecular chaperone and its Cdc37 co-chaperone help stabilize and activate over half of the human kinome. However, neither the mechanism by which these chaperones assist their client kinases nor why some kinases are addicted to Hsp90 while closely related family members are independent is known. Missing has been any structural understanding of these interactions, with no full-length structures of human Hsp90, Cdc37 or either of these proteins with a kinase. My thesis work focused on characterizing these interactions on a molecular level. I started with in vitro investigation of interactions between Hsp90/Cdc37 and Her2 kinase domain, only to find that under most conditions these proteins didn’t form a complex, although there was a subtle difference in kinase activity in response to Hsp90. I also was able to form in vitro complex between Hsp90/Cdc37 and bRaf kinase and followed this up by some preliminary biochemical characterization and EM. However, the main focus of my work was cryoEM work on Hsp90/Cdc37/Cdk4 kinase complex, where I was able to attain a 3.9Å reconstruction of this complex. In this structure, Cdk4 is in a novel conformation, with its two lobes completely separated. Cdc37 mimics part of the kinase N-lobe, stabilizing an open kinase conformation by wedging itself between the two lobes. Finally, Hsp90 clamps around the unfolded kinase β5 strand and interacts with exposed N- and C- lobe interfaces, safely trapping the kinase in an unfolded state. Based on this novel structure, extensive previous data, and also recent advancements from other groups I propose a new model of kinase activity and regulation.

A plasma diagnostic technique has been experimentally demonstrated where optical emission measurements of relative intensities of spectral lines in the violet range were combined with available electron-impact cross sections to yield absolute Ar metastable species concentration. An enabling factor of this analysis was that the electron excitation pattern was quite different between the Ar ground state and the metastable state. The result of this pattern was that the optical spectrum was unique depending on whether the emission was generated by direct excitation from the ground state, or by stepwise excitation from one of the metastable states. This study has shown that a model combining Ar excitation cross sections can fit the experimental spectral distributions by varying the ratio of the metastable state density and the E/N within the discharge. The absolute density obtained through optical emission spectroscopy was compared to measurements using laser diode absorption in order to confirm the results.

This thesis presents a new technique for measuring total absolute collision cross sections. Using this technique, the total absolute collision cross sections were determined for neon in the (3s)3P2 metastable state with ground state thermal atoms and molecules. A magneto-optical trap (MOT) is used in this technique which infers the cross sections via the measurement of population dynamics within the MOT to determine the collision cross section. This technique is capable of providing benchmark measurements of total absolute collision cross sections. The measurements are unique for the low average collision energy which ranges between 11meV and 27meV for the dierent collision species and relatively low uncertainty of approximately 9.4%. The measurements were for neon in the (3s)3P2 metastable state with He, Ne, Ar, H2, O2, N2 and CO2. The measured cross sections were respectively 160±20Å2, 500±50Å2, 840±80Å2, 230±20Å2, 1000±100Å2, 1300.0±100Å2, 830±80Å2. The measurements made using this technique have small uncertainties, of the order of 10% of the measured cross section. As Ne* does not have the energy to ionize He, the Ne*-He collision was entirely elastic and the validity of this technique was conrmed by comparing the experimental result for this collision with an approximation for the elastic collision cross section based on van der Waals forces. The calculation based on this approximation yielded an elastic cross-section of 168.88Å2 for the Ne*-He system. This theoretical value compared favourably and within the uncertainties of the experimental measurement for the Ne*-He collision of 160±20Å2. To be able to perform these investigations a rebuild and partial redesign of the Griffith University metastable neon trapping apparatus was necessary and was included in this work.