Mg-Al-Ni alloys were prepared by powder metallurgy, and their microstructure and elevated temperature mechanical properties were investigated. Results indicate that, in addition to α-Mg matrix, both coarse Al;Ni;part...Mg-Al-Ni alloys were prepared by powder metallurgy, and their microstructure and elevated temperature mechanical properties were investigated. Results indicate that, in addition to α-Mg matrix, both coarse Al;Ni;particles and fine Al Ni nano-particles exist in the Mg-Al-Ni alloys. The strength at 150?C is improved with the increase in Ni content. Mg-18.3Al-8Ni alloy possesses a compressive strength of234.7 MPa and a yield strength of 146.5 MPa. Plasticity is also improved with a low concentration of Ni. Mg-11.3Al-2Ni alloy possesses a compression ratio of 17.3%. The phases of Al;Ni;and Al Ni in the alloys block the movements of grain boundaries and dislocations during the deformation at elevated temperature. The existence of Al Ni phase provides a non-basal slip system, leading to the improvement in plasticity. Finally, the formation mechanism of Al-Ni phases in the process is discussed with thermodynamics and kinetics.展开更多
【目的】杨树萤叶甲(杨毛臀萤叶甲)(Agelastica alni orientalis Baly)主要分布于新疆,是杨、柳及苹果等林果的重要食叶害虫,对作物的严重危害期通常在幼虫期,难以对此做出准确鉴定。运用DNA条形码技术可以对害虫各龄期的标本进行快速...【目的】杨树萤叶甲(杨毛臀萤叶甲)(Agelastica alni orientalis Baly)主要分布于新疆,是杨、柳及苹果等林果的重要食叶害虫,对作物的严重危害期通常在幼虫期,难以对此做出准确鉴定。运用DNA条形码技术可以对害虫各龄期的标本进行快速和准确的鉴定。【方法】通过提取杨树萤叶甲的基因组DNA,以线粒体细胞色素氧化酶(COⅠ)基因作为通用引物进行PCR扩增,最后获得准确的碱基序列作为杨树萤叶甲的DNA条形码。【结果】根据杨树萤叶甲在不同龄期的DNA序列一致的原理,运用DNA条形码研究技术,获得了杨树萤叶甲成虫和三龄幼虫的COⅠ基因序列,并进行了序列分析。结果显示相似性最高可达97.74%。获得的序列可以用于对杨树萤叶甲的禄步鉴定。【结论】DNA条形码技术可简单、快速、准确的鉴定不同龄期杨树萤叶甲的标本,为及时采取害虫防治措施提供基础数据。展开更多
基金financially supported by the Key Research and Development Program of China(No.2022YFB2404102)the National Natural Science Foundation of China(Nos.51971093,52171158)the Key Research and Development Program of Shandong Province,China(Nos.2021ZLGX01,2022CXGC020308)。
基金supported by the National Natural Science Foundation of China (No. 51671063)the Research Fund for the Doctoral Program of Higher Education (No. 20132304110006)+1 种基金the Fundamental Research Funds for the Central Universities (No. HEUCF20161016)the Harbin City Application Technology Research and Development Project (Nos. 2015AE4AE005, 2015RQXXJ001, 2016AB2AG013)
文摘Mg-Al-Ni alloys were prepared by powder metallurgy, and their microstructure and elevated temperature mechanical properties were investigated. Results indicate that, in addition to α-Mg matrix, both coarse Al;Ni;particles and fine Al Ni nano-particles exist in the Mg-Al-Ni alloys. The strength at 150?C is improved with the increase in Ni content. Mg-18.3Al-8Ni alloy possesses a compressive strength of234.7 MPa and a yield strength of 146.5 MPa. Plasticity is also improved with a low concentration of Ni. Mg-11.3Al-2Ni alloy possesses a compression ratio of 17.3%. The phases of Al;Ni;and Al Ni in the alloys block the movements of grain boundaries and dislocations during the deformation at elevated temperature. The existence of Al Ni phase provides a non-basal slip system, leading to the improvement in plasticity. Finally, the formation mechanism of Al-Ni phases in the process is discussed with thermodynamics and kinetics.
文摘【目的】杨树萤叶甲(杨毛臀萤叶甲)(Agelastica alni orientalis Baly)主要分布于新疆,是杨、柳及苹果等林果的重要食叶害虫,对作物的严重危害期通常在幼虫期,难以对此做出准确鉴定。运用DNA条形码技术可以对害虫各龄期的标本进行快速和准确的鉴定。【方法】通过提取杨树萤叶甲的基因组DNA,以线粒体细胞色素氧化酶(COⅠ)基因作为通用引物进行PCR扩增,最后获得准确的碱基序列作为杨树萤叶甲的DNA条形码。【结果】根据杨树萤叶甲在不同龄期的DNA序列一致的原理,运用DNA条形码研究技术,获得了杨树萤叶甲成虫和三龄幼虫的COⅠ基因序列,并进行了序列分析。结果显示相似性最高可达97.74%。获得的序列可以用于对杨树萤叶甲的禄步鉴定。【结论】DNA条形码技术可简单、快速、准确的鉴定不同龄期杨树萤叶甲的标本,为及时采取害虫防治措施提供基础数据。
