New coating eliminates need for barrier films, says Finnish team

New coating eliminates need for barrier films, says Finnish team
The ALD technology was developed in Finland in the 1970s and has been utilised mainly in microelectronics to date but work at VTT has demonstrated that the coating is applicable to trays, folded boxes and tubes designed for food and medical products.

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Nanothermal trumpet: thermoacoustic sound source made with a suspended metal nanowire

From the paper “Suspended metal wire array as a thermoacoustic sound source,” Appl. Phys. Lett. 95, 163102 (2009); by AO Niskanen, J. Hassel, M. Tikander, P. Maijala, L. Grönberg, P. Helistö, from VTT Technical Research Centre of Finland, PO BOX 1000, 02044 VTT, Finland. dx.doi.org A suspended metal wire array is used to produce high-pressure sound waves over a wide spectrum using the thermoacoustic effect. It is fabricated with an air-bridge arrays containing up to 2×105 wires covering an area of a few square centimeters. The supporting silicon wafer was isotropically plasma etched to release the wires thereby avoiding heat contact with the substrate. Sound pressure levels reaching 110 db at a distance of 8 cm were demonstrated near 40 khz in free field. The devices are also able to reproduce music and speech. They have potential for applications especially in the ultrasound range.