“哥伦比亚”号航天飞机空难原因及其材料分析

从材料的冶金分析入手,分析了“哥伦比亚”号航天飞机爆炸的原因。材料分析表明:航天飞机在再入大气层时,在靠近左机翼前缘的8号和9号面板之间的缝隙处,高温离子流穿入,熔化了铝和铁、镍基合金等支撑结构,引起航天飞机解体。在材料的研究中,建议对新材料当前要以有限目标为主,按需求建立起我国的新材料及其制备工艺体系;对于航空、航天与核动力领域中广泛采用的通用关键材料,应该加强其制备工艺的研究,特别是可视化铸造技术的研究。

On the Application of TED Speeches Into Flipped Learning for English Learners Taking the TED Speeches With the Keyword ＂Transportation＂ as an Example

Flipped learning is a reversal of the traditional teaching strategy, which has changed the timing of teacher＇s lectures and homework. In this revolutionary situation, the appropriateness of the before-class videos and other materials and the arrangement of class in the classroom play an important role in the fulfillment of application of the materials. Classical TED speeches are the excellent options for English language learners＇ flipped learning. This paper tends to make a case study of the application of TED speeches into flipped learning, taking the speeches with the keyword ＂transportation＂ as an example.