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公开(公告)号:US2193456A
公开(公告)日:1940-03-12
申请号:US9533636
申请日:1936-08-11
Applicant: OTTO HELLMANN
Inventor: OTTO HELLMANN
IPC: C10B7/14
CPC classification number: C10B7/14
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公开(公告)号:US1854161A
公开(公告)日:1932-04-12
申请号:US19562827
申请日:1927-06-01
Applicant: OTTO HELLMANN
Inventor: OTTO HELLMANN
IPC: C10B7/02
CPC classification number: C10B7/02
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