2μm激光器国内外发展状况研究

2μm激光可通过Tm，H0双掺固体激光器、单掺Tm固体激光器、单掺Ho固体激光器、光纤激光器、光学参量振荡器等五类激光器来获得。本文从激光器类型、激光器参数、输出性能等方面全面详细地研究了国内外2μm激光器的发展状况，对国内2ixm激光器和中波3～5μm激光的发展具有重要的指导意义。

Benthic Habitat Quality Assessment Based on Biological Indices in Xiaoqing River Estuary and Its Adjacent Sea of Laizhou Bay,China

Based on the macrofauna data(2008-2011) in Xiaoqing River estuary and its adjacent sea, Laizhou Bay of Bohai Sea, China, the AZTI Marine Biotic Index(AMBI) and Multivariate AMBI(M-AMBI) were used for benthic habitat quality(BHQ) assessment. Results showed that BHQ presented an obvious trend of improvement along the direction of stream channel and river mouth, and in the coastal areas. AMBI and M-AMBI were significantly related to environmental pressure gradient data. Therefore, the two indices can well indicate BHQ in the studied area. However, there were significant differences between results of the two indices. In the cases of low taxa number and high abundance of single species, AMBI might overestimate BHQ. We thus adjusted its thresholds to solve this problem. And M-AMBI might overestimate BHQ when benthic assemblage was dominated by the opportunistic species. Then we could raise the weight of AMBI in the calculation of M-AMBI to handle the problem.

X100高压输送管线裂纹止裂预测探讨

参考目前X100高钢级管线全尺寸气体爆破试验结果,讨论了管线钢材料流变应力、DWTT能量对管道止裂行为的影响,研究分析了现有裂纹止裂预测模型对X100高钢级管线预测的局限性。提出了M参量(M=CVN1/2/YS)的预测方法。分析结果表明,用参量M可以很好地预测管线裂纹扩展和止裂。结合材料流变应力、DWTT能量和参量M可以为实际管道工程用钢管的关键力学性能指标的确定提供支持。