Two kinds of soft particles gypsum and mica particles which take relatively major proportion in compositionofdust often can be found in failure contact areas.
云母和石膏是两种在细尘粒中比例较大的软质颗粒物，出现在失效触点区域造成电接触故障。
2
The purpose of researches on urban dust is focused on the source ofdust material, compositionofdust, distribution, migration and evolution, pollution effects and prevention and cure.
研究城市灰尘的目的是研究其物质来源、物质成分、分布规律、迁移演化、污染效应、防治治理等。
3
It is hypothesized that the primordial cloud ofdust and gas from which all the planets are thought to have condensed had a composition somewhat similar to that of Jupiter.