Phys.org September 16, 2021 A liquid deposited on a surface tends to move along directions that reduce surface energy, which is mainly dictated by surface properties rather than liquid properties, such as surface tension. Achieving well-controlled directional steering remains challenging because the liquid-solid interaction mainly occurs in the 2D domain. An international team of researchers (China, Hong Kong) has shown that the spreading direction of liquids with different surface tensions can be tailored by designing 3D capillary ratchets that create an asymmetric and 3D spreading profile both in and out of the surface plane. Such directional steering is also accompanied […]
Tag Archives: Heat transfer
Heat energy leaps through empty space, thanks to quantum weirdness
Phys.org December 11, 2019 Recent theory has predicted that quantum fluctuations of electromagnetic fields could induce phonon coupling across a vacuum and thereby facilitate heat transfer. Researchers at UC Berkeley experimentally demonstrated heat transfer induced by quantum fluctuations between two objects separated by a vacuum gap. They used nanomechanical systems to realize strong phonon coupling through vacuum fluctuations and observed the exchange of thermal energy between individual phonon modes. The experimental observation agrees well with their theoretical calculations and is unambiguously distinguished from other effects such as near-field radiation and electrostatic interaction…read more. TECHNICAL ARTICLE