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BACKGROUND Determination of strontium (Sr) and neodymium (Nd) isotopic composition in geological samples by Multi-collector Inductively Coupled Plasma-Mass Spectrometry (MC-ICP-MS) needs a lengthy and complex chemical preparation procedure. Moreover, samples cannot be dissolved completely. OBJECTIVES To effectively digest samples and eliminate interferences from the experimental process. METHODS Geological samples were dissolved by microwave digestion. The processes of Sr, Nd chemical separation and mass spectrometry analyses were studied. In particular, the recovery and memory effect of resin column were investigated. RESULTS The research shows that after ten times usages Sr and Nd procedure, blanks of the resin are less than 1.0 ng. However, the recovery decreases significantly from 98% to 20% and 90% to 50%, respectively. If the analyzed samples contain low concentrations of Sr and Nd, which are insufficient for mass spectrometry analysis, it is suggested that Sr special effect resin should be used no more than 5 times and AG50W-X8 and Ln resin should be used no more than 10 times. The entire procedure is applied in the separation of Sr and Nd of international standard geological samples (BCR-2, W-2a, BHVO-2, AGV-2). The acquired 87Sr/86Sr and 143Nd/144Nd ratios are consistent with those in the literature, and the instrumental internal precision 2SE (n=50) and methodological external precision 2SD (n=6) are better than 0.0015%. CONCLUSIONS The proposed method meets the requirement of high-precision measurement of Sr and Nd isotopic composition in geological samples.

Bonded repair is efficient and widely-used repair technique for composite structures. Tests were conducted to study the tensile property of scarf repaired and external bonded repaired composite laminates with different repair parameters. The results show that the recovery of failure strength of scarf repaired laminates is about 66%-91% while external bonded repaired laminates is about 44%-61%.When reducing scarf ratio, repairing in double sides, curing in autoclaves, the scarf repair specimens can reach a higher recovery rate of failure strength. When repairing in double sides, enlarging the size of patches, the external bonded repaired specimens can also reach a higher recovery rate of failure strength. Based on the test results, finite element models were established to predict the failure loads and failure modes of specimens, and to analyse the stress distribution and progressive damage process of specimens, which can provide a reference to the designing in the repair projects.

Objective: To compare clinical outcomes of superior labrum from anterior to posterior (SLAP) repair and biceps tenodesis in treating type I SLAP injury., Methods: From March 2009 to March 2012, 38 patients with type II SLAP injury were treated with SLAP repair and biceps tenodesis, and all patients were unilateral SLAP injury. Sixteen patients treated with biceps tenodesis included 8 males and 7 females with an average age of (49.3±3.7) years old (ranged, 45 to 54); 10 cases were on the left side and 6 cases on the right side; 10 cases were caused by falling down, 2 cases were caused by throwing damage and 4 cases were caused by daily life damage; the time from injury to operation were from 3 to 8 weeks. Twenty-two patients treated with SLAP repair included 14 males and 8 females with an average age of (49.0±2.8) years old (ranged, 44 to 56); 13 cases were on the left side and 9 cases were on the right side; 14 cases were caused by falling down, 5 cases were caused by throwing damage and 3 cases were caused by daily life damage; the time from injury to operation were from 3 to 7 weeks. Preoperative, postoperative at 6 months, 1 year and 2 years' UCLA and SST score were compared between two groups., Results: There was no significant differences in UCLA and SST score between two groups before operation. At 6 months after operation, UCLA and SST score in biceps tenodesis group was higher than SLAP group, and action,range of anteflexion, strength of anteflexion, degree of satisfaction in biceps tenodesis group was higher than SLAP group. There was no significant meaning in SST and UCLA score between two groups at 1 and 2 years after operation., Conclusion: Short-term efficacy of biceps tenodesis for SLAP injury is better than SLAP repair, but long-term efficacy is fairly.