Elucidating the mechanisms responsible for sub-microsecond desorption of water and other impurities from electrode surfaces at high heating rates is crucial for understanding pulsed-power behavior and optimizing its efficiency. Ionization of desorbed impurities in the vacuum regions may create parallel loads and current loss. Devising methods to limit desorption during the short time duration of pulsed-power will significantly improve the power output.
View Article and Find Full Text PDFMaterials (Basel)
September 2021
Helium is insoluble in most metals and precipitates out to form nanoscale bubbles when the concentration is greater than 1 at.%, which can alter the material properties. Introducing controlled defects such as multilayer interfaces may offer some level of helium bubble management.
View Article and Find Full Text PDFType III solar radio bursts are the Sun's most intense and frequent nonthermal radio emissions. They involve two critical problems in astrophysics, plasma physics, and space physics: how collective processes produce nonthermal radiation and how magnetic reconnection occurs and changes magnetic energy into kinetic energy. Here magnetic reconnection events are identified definitively in Solar Dynamics Observatory UV-EUV data, with strong upward and downward pairs of jets, current sheets, and cusp-like geometries on top of time-varying magnetic loops, and strong outflows along pairs of open magnetic field lines.
View Article and Find Full Text PDFPt is an active catalyst for diesel exhaust catalysis but is known to sinter and form large particles under oxidizing conditions. Pd is added to improve the performance of the Pt catalysts. To investigate the role of Pd, we introduced metallic Pt nanoparticles via physical vapor deposition to a sample containing PdO nanoparticles.
View Article and Find Full Text PDFA 100X magnification, ± 2.5° field of view micro-concentrating optical system has been developed for a microsystems-enabled photovoltaic (MEPV) prototype module using 250 µm diameter multi-junction "stacked" PV cells.
View Article and Find Full Text PDF