The surface structures of catalysts have in some instances a large impact on their catalytic properties. On the other hand, historically, mild reactions are not considered to be surface structure sensitive. In this thesis we report on our observation that both the size and the shape of Pt nanoparticles strongly affect the selectivity of glycerol oxidation, a reaction that can proceed at low temperature and under atmospheric pressures. In a series of experiment using Pt/SiO2 catalysts with average particle sizes varying from 3.9 to 5.7 nm, it was determined that selectivity toward primary carbon oxidation increases as the proportion of larger particles increases. Together with CO IR titration result, these results appears to indicate that larger Pt particles with flat surfaces and extensive fractions of atop and bridge sites may promote primary carbon oxidation, whereas edge, corner, and other low-coordination Pt sites may promote secondary carbon oxidation. Further catalyst characterization and kinetic experiments will be needed to confirm this tentative conclusion. Tetrahedral- and cuboctahedral-shaped Pt catalysts were also tested for the glycerol oxidation reaction, and cuboctahedral-shaped Pt nanoparticles were found to display higher activity and higher selectivity toward primary carbon oxidation.

Measurement of particulate matter (PM) emission of light-duty vehicles (LDVs) is a complex issue with many stakeholders, including engine manufacturers, health effect scientists, climatologists and regulatory agencies. With particulate emission regulatory limits in California and United States decreased by more than two orders of magnitude since the 80s, efforts continue to investigate alternatives to the gravimetric method for quantification of LDVs PM emission.

Several alternative metrics including total particle number (TPN), solid particle number (SPN), black carbon (BC), and particle surface (PS) area were measured along with gravimetric PM mass to study the correlation between different methods, using a variety of LDVs chosen to represent different emission levels and a range of current technologies in the modern fleet. It was found that gravimetric PM mass is strongly dependent on chemical nature of the PM. Thus correlations of gravimetrically determined PM mass with alternative metrics were different between two different testing cycles (e.g. FTP vs SFPT-US06). Alternative metrics are free from such cycle dependency which is due to adsorption artifact and therefore considered as a good future metric or supplemental metric such as SPN for EU regulation. Particle surface (PS) area turned out to be very sensitive with wide range and current instrumentation has a room to improve in terms of measuring tunnel blank and reducing electrometer drift.

Quaternary stereogenic centers are important structural motifs in natural products and biologically active compounds, and present some of the most challenging constructs in organic synthesis. The first part of this thesis reports our development of a highly enantioselective alkylation of both α-alkynyl carboxylic acids and α-allenoic acids forming all-carbon quaternary centers. Chiral lithium amides are used as noncovalent stereodirecting auxiliaries. Accompanying crystallographic studies provide mechanistic insight into the structure of well-defined chiral aggregates, highlighting cation-π interactions between lithium and alkyne groups. The synthetic utility of this method is further demonstrated in the enantioselective total synthesis of (+)-goniomitine.The second part will outline our efforts towards two heterodimeric bisindole alkaloids, bousigonine A and bisleuconothine A. The synthesis features a divergent-convergent retrosynthetic design that allows for efficient, practical synthesis with shorter longest linear sequence and fewer total steps. All the quaternary centers are formed using the asymmetric alkylation methods developed in our group. Three monoindole fragments in the target molecules, eburnamonine, quebrachamine and aspidospermidine are obtained and the final assemble of the monoindole fragments is under investigation.

The CE-CERT Steam Hydrogasification Technology efficiently converts carbonaceous materials to high energetic synthesis gas. This thesis investigates the direct production of gasoline range liquid hydrocarbons with high iso-paraffin content from synthesis gas. The goal is to provide a process to efficiently produce renewable gasoline that can be used directly without modification of engine or infrastructure.

An H-ZSM-5 shell Co/Al2O3 Fischer-Tropsch catalyst is prepared using a secondary-growth hydrothermal synthesis method. The catalyst not only synthesizes long-chain hydrocarbons from synthesis gas, but also cracks and isomerizes them into gasoline-range hydrocarbons with high iso-paraffin content. Characterization results show that the catalyst has good H-ZSM-5 shell coverage with no cracks or pinholes, with a shell thickness is around 4.29 μm. H-ZSM-5 shell composition is confirmed by EDX and XRD. In addition, the zeolite-shell catalyst has a 10% increase of surface area, compared to a conventional Fischer-Tropsch catalyst.

A high-temperature high-pressure lab-scale continuous Fischer-Tropsch reactor with LabVIEW automation system was designed and built. The reactor system has online gas and liquid sampling capabilities. It also has a PID controller with gain scheduling for precise heating control during Fischer-Tropsch synthesis test. Safety during reactor operation is ensured with alarms and automatic emergency response system.

Performance of a H-ZSM-5 shell Co/Al2O3 Fischer-Tropsch catalyst was investigated under various conditions. A maximum CO conversion of 97.1%, with a highest gasoline yield of 58% and iso-paraffin selectivity of 14.3%, was obtained. Sensitivity analysis shows that reaction temperature significantly affects CO conversion and iso-paraffin selectivity. Catalyst silicon to aluminum ratio also influences iso-paraffin selectivity, but has no effect on CO conversion. In addition, H-ZSM-5 shell Co/Al2O3 Fischer-Tropsch catalyst has much less carbon deposition than conventional catalyst, which can help reduce catalyst deactivation rate.

Silicon photonics is a rapidly growing field of technology that focuses on the use of silicon-based materials to manipulate light in order to transmit information. By leveraging the unique properties of silicon-based materials, silicon photonics offers several advantages over conventional electronic-based technologies. Silicon is a mature CMOS material and is one of the most widely used integrated photonic platforms. However, silicon has a relatively smaller band gap, which limits its power handling capabilities due to two-photon absorption, making it unsuitable for high-intensity nonlinear optical processing.

In this dissertation, I will show our effort in developing silicon rich carbide (SRC) as a new photonic material that addresses the limitations of silicon. By increasing the silicon content, SRC offers enhanced nonlinearity while maintaining a wider band gap than silicon. Results demonstrate a 7-fold increase in nonlinearity compared to stoichiometric silicon carbide. Additionally, preliminary work on a Si/SRC hybrid waveguide modulator is presented, utilizing the quadratic EO effect (DC Kerr effect).

Another important active photonic building block is the phase shifter. Many photonic applications, including optical modulators and all-optical switches, rely on tunability to control the optical properties in PICs. One of the common mechanisms that is used for circuit tuning is the thermo-optic effect. The dissertation will show our work on exploring the thermo-optic coefficient (TOC) of the SRC material and demonstrates a 3-fold improvement in the TOC with respect to the stoichiometric silicon carbide. An efficient thermo-optic phase shifter is also demonstrated using SRC.

In conclusion, SRC, with its high nonlinearities, high power handling capability, high TOC, and compatibility with CMOS processing, shows great potential as a promising material candidate for integrated photonic applications.

Lidars are becoming common components for remote sensing in many emerging applications such as autonomous vehicle and facial recognition. To accurately visualize the point cloud for further data processing, metrics such as precision, sampling rate, and linearity are important. Phase detection has been widely used for high precision, however, resolving the ranging ambiguity beyond one carrier period lowers the system acquisition rate. Pulsed direct time-of-flight (ToF) detection, on the other hand, provides high sampling rate with single-shot measurements, but the precision is limited by the walk error. In this work, we present a pulsed-coherent detection to combine the advantages from both the pulsed detection with high sampling rate and the phase detection with high precision. The CW laser source is amplitude modulated by a high RF carrier and a low frequency pulsed envelope modulation. At the receiving end, the segmented time-of-flight detection algorithm measures the phase shift of the RF carrier as fine ToF and counts the arrival time of the low-frequency mask's envelope as intermediate and coarse ToF. This pulsed-coherent lidar can simplify the optical setup while achieving high precision and high sampling rate. Three different receiver prototypes are demonstrated with two test chips: (1) analog-based receiver which has separate paths for coarse and fine detection. The coarse ToF is recorded by detecting the pulse’s edge whereas the fine measurement is measured by phase detection. The proposed post-edge detection with automatic gain control loop suppresses the walk error; (2) DSP-based homodyne receiver which we reuse the same chip of analog-based receiver and collect the data by sub-sampling ADCs. Both the coarse detection and fine detection are calculated in the digital signal processor (DSP). This receiver improves the immunity to PVT variation and inherently aligns the segmented measurements by using the sampling clock as the reference hence achieving better precision at higher sampling rates; (3) DSP-based heterodyne receiver which we take a lower frequency clock as the reference input and use a local phase-locked loop (PLL) to generate the clock for the down-conversion mixer. This LO generation reduces the coupling between the clock and the incoming signal. Also, the two-step down-conversion with digital down-mixing improves the power efficiency and immunity to PVT variation without additional calibration. In addition to the innovation of the architecture, this work also presents some novelties of the circuit implementations: (1) we introduce a narrowband input-matching to improve the noise performance which uses direct wire-bonding between the photodiode bare die to the low noise amplifier; (2) we implement phase-invariant amplifiers to operate the lidar system in wide dynamic range; (3) we build a low phase noise LO generator based on a ring-VCO-based phase-locked loop. Two test chips are fabricated in TSMC 28nm CMOS technology. We successfully demonstrate the lidar system with both 1-D scanning and 2-D scanning. The system achieves <10�m precision with 5-MHz integration bandwidth and 30-�m INL at 2.5-m distance.

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