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A 6005A aluminum alloy was produced by an actual surface with less defects, multiple defect samples, and as-ground samples for the purpose of investigating the effect of aluminum alloy surface damage on corrosion resistance and its corrosion electrochemical behavior in seawater. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were employed in order to characterize the surface states of the 6005A aluminum alloy. The results show that the surface defects caused by aluminum alloy products consist mainly of scratches. With the increase of surface defects, an obvious increase in Ra is observed, and Ra could quantitatively describe the severity of surface damage. In simulated seawater, the 6005A aluminum alloy undergoes comprehensive corrosion and pitting; thereby, corrosion resistance deteriorates as the amount of defects increases. Electrochemical test results show that the larger the number of surface defects is, the greater are the roughness and lower corrosion potential. Additionally, the greater the corrosion current density is, the worse is the corrosion resistance. A 6005A aluminum alloy that has suffered surface damage and whose corrosion resistance was affected due to seawater can cause the following:the more surface defects are, the greater is the roughness and surface film damage; thereby, the plastic deformation of the surface becomes more serious. The protective layer of the oxide filmis reduced, and the substrate has a higher corrosion rate. The passive film for the samples with less defects is more compact and uniform and could protect the substrate, while effectively reducing further corrosion.

Objective: To observe the efficacy and safety of biological heart valves (BHV) and mechanical heart valves (MHV) in childbearing age women (CAW) during the perinatal and short-moderate term postoperative (SMTP) periods., Methods: There were 33 patients [(25.2±7.1) yr.] undergoing BHV replacement from September 2009 to December 2014 had completely followed-up,whose data were retrospectively collected. A 1∶4 matching study was conducted,therefore there were 132 patients undergoing MHV were included. The collected date included the clinical outcomes in the perioperative, perinatal,and SMTP period event-free survival (EFS) was determined using the Kaplan-Meier method and compared using the log-rank test., Results: The average follow-up time was (5.8±3.6) years,and the two groups had similar baseline . The clinical outcomes difference of perinatal and SMTP between the two groups were not significant. There were 17 patients in BHV group and 60 in MHV group with pregnancy and birth experiences (PBE),which also showed no significant difference for adverse events both in the maternity and in the fetus. The rates of valve-related adverse events of BHV replacement patients with and without PBE were 5.9% and 0% at 3 years after the operation, and 11.8% and 5.9% after 5 years. PBE was not identified as an adverse prognostic factor for EFS ( P =0.43)., Conclusion: Either artificial BHV or MHV replacement can achieve ideal SMTP effect in CAW. BHV seems not superior to MHV. Pregnancy and birth experience will not increase the risk of BHV relevant adverse events., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).)