2021, Vol. 24(1): 64-70    DOI:
 Analysis of effects of operating parameters on rate of penetration in drilling process with air down - the - hole hammer
 HO Yinchol ,PAK Kumdol ,PENG Jianming,RI Jaemyong , KIM Yongnam  and CHOE Cholho 
 1. School of Information Science and Technology,Kim Chaek University of Technology,Pyongyang 999093,D. P. R. Korea; 2. School of Resource Exploration Engineering,Kim Chaek University of Technology,Pyongyang 999093,D. P. R. Korea; 3. College of Construction Engineering,Jilin University,Changchun 130026,China
Received null  Revised null
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