Compared it with conventional billet, billet cast with high frequency electromagnetic field, on which depth of surfaceoscillation mark was decreased remarkably, had a smooth surface.
施加高频电磁场的铸坯与传统连铸坯相比，表面振动痕深度明显减小，且表面光滑。
2
La Nina is a natural 3-6-year cycle, and the cold stretch of a periodic thermal oscillation in ocean surface temperatures that occurs throughout the tropical Pacific.
拉尼娜每隔3到6年发生一次，太平洋热带地区海水温度会随之发生周期性的异常变冷。
3
The movement locus precision of mould oscillation equipment does much influence on strand surface quality.