Barriers and strategies in listening comprehension

A variety of barriers to listening comprehension are illustrated in this paper. They are analyzed respectively and several effective strategies are also presented afterward. The barriers to listening are those of psychological quality, language knowledge, cultural background, Chinese interference and so on. The strategies should be as follows: training students' psychological quality, strengthening the teaching and learning of language knowledge, comparing cultural differences, using student-centered teaching method and combining intensive listening and extensive listening.     

汽车轮毂新型铝合金热处理工艺优化研究

汽车轮毂作为汽车行驶部件之一,轮毂的性能也对汽车安全行驶起到决定性作用。文章对汽车铝合金轮毂特性进行概述,并对铝合金轮毂热处理工艺进行分析,通过固溶处理和时效处理两方面对轮毂热处理机理进行分析,并通过试验得出铝合金轮毂在特定温度、恒温时间和时效时间下的最佳性能。