| Popis: |
Everyone has probably had the experience of feeling shocked when touching a doorknob after walking across a carpet. This is one of the many examples of electrostatic charging on surfaces. Electrostatic charging, or contact electrification, is a well-known phenomenon in various instances. However, the charging mechanism remains poorly understood. This thesis will elucidate the scientific basis of contact charging on quartz (0001) and sapphire (0001) surfaces with first principle electronic calculations, supported by experimental results. Both experiments and simulations show consistent charging direction and magnitude results, demonstrating the possibility to address electrostatic charging on surfaces of more complicated structures. Electrostatic discharge can happen as a result of charge buildup on surfaces, leading to the gas breakdown. Inadvertent gas breakdown can be harmful, such as damage to microelectronic components. Intentional gas breakdown can be utilized to generate plasma. With high reactivity at relative low temperature, plasma is able to dissociate thermodynamically stable molecules near room temperature, such as carbon dioxide and methane. In this work, we modulate power, volume, flow rate, pressure, voltage, discharge gap distance, and the simultaneous use of catalysts on conversion processes to control plasma reactions. Our combined experimental and multiscale simulation techniques provide a guidance to optimize plasma conversion processes. |
