Submerged macrophytes is key community in shallow lake ecosystem.It plays important role in water environmental quality and aquicolous ecosystem structure.
Graphalloy components can withstand temperature fluctuations ranging from cryogenic to 1000F and are dimensionally stable even when submerged or under load.
The purpose of prebending process of longitudinal submerged arc welding pipe production line is introduced;character of roller prebending and mould press type prebending is analyzed.