建筑结构在进行地震作用计算时，确定所需计入的振型数是必不可少的。
It is necessary to decide the reasonable mode number when we analyze earthquake action in construction design.
为了进行更准确的抗风抗震分析，以及将来桥梁的健康检测，实验测量桥梁的自振特性是必不可少的。
For the advanced analysis and health monitoring of the bridge, the vibration characteristics of the structure must be measured.
直线振动筛(直线筛)稳定可靠、消耗少、噪音低、寿命长、振型稳、筛分效率高等优点。
Linear Vibrating screen (linear sieve) stable and reliable, consume less, low noise, long life, vibration-type steady, screening and high efficiency.
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