Study of silica aerogel grain surfaces by using a positron age–momentum correlation technique |
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| Authors: | N Suzuki T Oonishi T Hyodo T Chang |
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| Institution: | (1) Institute of Physics, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan, JP;(2) Laboratory of NAT, Institute of High Energy Physics, P.O. Box 2732, Beijing 100080, P.R. China, CN |
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| Abstract: | The effect of heat treatment on silica aerogel has been studied by a positron age–momentum correlation technique and infrared
measurement. A difference was observed between the momentum distributions of the electrons on the first layers of the silica
aerogel grain surfaces and the electrons in the grains in an as-supplied sample, but not in the sample heat treated at 800 °C.
A large change in the S parameter for the momentum distribution of the electrons on the first layer occurs around 200 °C.
This change correlates well with that of the infrared spectra, which show oxidation of the methoxyl groups at temperatures
above around 200 °C. This correlation reveals that those groups are mainly located on the first layer of the silica grains.
Received: 13 November 2000 / Accepted: 23 July 2001 / Published online: 30 October 2001 |
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| Keywords: | PACS: 71 43 Gt 78 70 Bj 82 55 +e |
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