双凹形

采用自行研制的具有方框形外特性的交流脉冲MIG焊接电源，又设计了双凹形焊接电流波形，即过零前后的电流波形均为脉冲大电流，有利于交流脉冲MIG焊接电弧的连续稳定。

A new AC pulse MIG welding process is introduced . And an outstanding welding current waveform capable of stabilizing the AC MIG welding arc is put forward . The current in electromagnetic forming is the impulse current .

结论：双凹形植骨较为适合颈椎前开槽多节段减压术后植骨融合术。

Conclusion : Dual concave bone grafting is more suitable for anterior cervical slotting multisegmental decompression following bone grafting .

危重度组MCV及球形红细胞比例增大，而双凹圆盘形红细胞比例减少，与轻中度组比较，差异均有非常显著性（P<0.01）。

The MCV and spherocyte proportion in the serious degree group increase , but double cave round shape disk red cell proportion reduce , the difference was significant ( P < 0.01 ) compared with the light-medium degree group .

在本文的模拟过程中，将前向跟踪法与晶格波尔兹曼法相结合来研究三维双凹碟形胶囊式红细胞的变形。

Lattice Boltzmann method combines with the front-tracking method to study the three dimensional deformation behavior of biconcave discoid capsule erythrocyte model .