Therefore, the conventional staggered distance model of ultra-close thin coal seam group during combined mining is put forward; and the theoretical research and physical simulation are carried out.
因此提出极近距离薄煤层群联合开采常规错距开采模型，并进行理论和物理模拟试验研究。
Burn through is the main problem of longitudinal seam welding of ultra-thin tube with small diameter. Assembly of the joint and welding technology are the key to solve the problem.
小直径超薄壁管纵缝焊接的主要问题是烧穿，解决这个问题的关键是严格控制焊接接头的装配质量及焊接工艺。
Burn through is the main problem of longitudinal seam welding of ultra-thin tube with small diameter. Assembly of the joint and welding technology are the key to solve the problem.
小直径超薄壁管纵缝焊接的主要问题是烧穿，解决这个问题的关键是严格控制焊接接头的装配质量及焊接工艺。
应用推荐