Original: D. , H.I. , N.I. ( twice ) ) ( Urdu : ) ; ( born April 27 , 1936 ) , best known as Dr. A. Q. Khan , is a Pakistani nuclear scientist and a metallurgical engineer , widely regarded as the leader of gas-centrifuge enrichment technology for Pakistan 's nuclear program .
Simplified: Abdul Qadeer Khan ( ; born April 1 , 1936 ) in Bhopal , is a Pakistani scientist and metallurgical engineer .