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A series of new 1,3,4‐oxadiazin‐5(6H)‐one derivatives (6a–n) of dehydroabietic acid were designed and synthesized as potential antimicrobial and antitumor agents. Their structures were characterized by IR, 1H NMR, 13C NMR, MS, and elemental analyses. All the title compounds were evaluated for their antimicrobial activity against four bacterial and three fungal strains using the serial dilution method. Among them, compound 6eshowed the highest antibacterial activity against Bacillus subtiliswith a minimum inhibitory concentration (MIC) value of 1.9 μg/mL. In addition, the in vitro cytotoxic activities of the title compounds were also assayed against three human carcinoma cell lines (MCF‐7, SMMC‐7721, and HeLa) through the MTT colorimetric method. As a result, compounds 6b, 6g, 6k,and 6mexhibited significant inhibition against at least one cell line with IC50values below 10 μM. Compound 6mwas especially found to be the most potent derivative with IC50values of 2.26 ± 0.23, 0.97 ± 0.11, and 1.89 ± 0.31 μM against MCF‐7, SMMC‐7721, and HeLa cells, respectively, comparable to positive control etoposide. A series of new 1,3,4‐oxadiazin‐5(6H)‐one derivatives of dehydroabietic acid (6a–n) were designed and synthesized as potential antimicrobial and antitumor agents. Among them, compound 6eshowed the highest antibacterial activity against Bacillus subtilis(MIC: 1.9 μg/mL). In addition, compound 6mexhibited the most potent cytotoxic activity with a IC50value of 0.97 ± 0.11 μM against SMMC‐7721 cells.

Using acoustic emission (AE) technique, test the blowout preventer (BOP) shell with a crack in the pressing process. Firstly, cut a notch of 100mm long and 5mm wide on a BOP shell and weld partly, then pressurized by pneumatic pumps. Test the BOP shell during the crack propagation by AE. The result showed that the AE technique can reflect the activities of the defects timely and effectively, and the destroy situation of the blowout preventer shell in the process of pressured and the location was accurate.