Pulsed laser deposition of thin films is a technology that has been explored in some detail. Because of the difficulty of monitoring in real time either the ablation process itself, or thin film growth, many studies have relied on diagnostics of either the ablated plume (emission, absorption, fluorescence) or the resulting films (Tc, Jc, X-ray, RBS) to infer information about the overall process. This indirect approach has provided some vital information for improving the production of high-temperature superconductors. In this study the plume dynamics during the in-situ pulsed laser deposition of YBa2Cu3O7-(delta ) thin films are investigated. The 248 and 308 nm lines of an excimer laser were used to generate a plume from a bulk YBa2Cu3O7-(delta ) target. Variations in the plume distribution as a function of processing gas, pressure, fluence, energy, and spot size were monitored by resulting film distribution and composition and time resolved emission imaging. Results indicate that the plume distribution can be controlled to some extent by the incident laser beam size; in addition, broadening increases with increasing oxygen pressure.
Short-term, community-based projects—from pop-up parks to open streets initiatives—have become a powerful and adaptable new tool of urban activists, planners, and policy-makers seeking to drive lastin
The present work demonstrates the use of light to move liquids on a photoresponsive monolayer, providing a new method for delivering analyses in lab-on-chip environments for microfluidic systems. The light-driven motion of liquids was achieved on photoresponsive azobenzene modified surfaces. The surface energy components of azobenzene modified surfaces were calculated by Van Oss theory. The motion of the liquid was achieved by generation of a surface tension gradient by isomerization of azobenzene monolayers using UV and Visible light, thereby establishing a surface energy heterogeneity on the edge of the droplet. Contact angle measurements of various solvents were used to demonstrate the requirement for fluid motion.
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