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改用感温材料 增强实验效果
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作者 聂建国 熊智勇 《小学科学》 2023年第7期34-36,共3页
根据教材的内容,苏教版科学五年级上册第二单元“热传递”中关于固体热传导实验和固体导热性的实验,是将凡士林涂在固体表面,然后加热固体。用凡士林受热熔化的过程来显示热传导的过程,再用凡士林熔化的快慢来显示固体导热性的强弱。但... 根据教材的内容,苏教版科学五年级上册第二单元“热传递”中关于固体热传导实验和固体导热性的实验,是将凡士林涂在固体表面,然后加热固体。用凡士林受热熔化的过程来显示热传导的过程,再用凡士林熔化的快慢来显示固体导热性的强弱。但是在实际的操作过程中存在一些问题,主要是凡士林加热熔化以后变得透明,学生不容易看清,而且由于学生年龄小,涂抹凡士林容易将桌面等其他物品弄脏,影响实验室的卫生。对此,笔者对实验材料进行了一些改进,用感温材料代替凡士林涂抹在金属片上,用感温材料颜色的变化来显示固体热传导现象,用涂在不同固体上感温材料颜色变化快慢来显示固体导热性的强弱,更加直观,实验现象也非常明显,而且可以反复实验,同时解决了卫生的问题,收到了良好的实验效果。 展开更多
关键词 小学科学 感温材料 热传递实验 改进
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Temperature in High Temperature SHPB Experiments
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作者 邓志方 谢若泽 +2 位作者 颜怡霞 李思忠 黄西成 《Transactions of Tianjin University》 EI CAS 2008年第B10期536-539,共4页
As an experimental technique, it’s desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments. However, the temperature in specimen decreases and the tempe... As an experimental technique, it’s desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments. However, the temperature in specimen decreases and the temperature of bars increases when specimen starts to contact with bars, which induces the nonuniform temperature distribution in specimen, and may result in inac-curacy of experimental results. In this paper, the temperature distributions of specimen and bars in high temperature SHPB experiments were investigated while the specimen was heated alone. Firstly, the temperature history of specimen was measured at different initial temperatures by ex-periments, then simulation was carried out. Simulation results were consistent with experimental results by adjusting the thermal contact coefficient between specimen and bars. By this way, the thermal contact coefficient and simulation results were validated, and the proper cold contact times of specimen and bars in high temperature SHPB experiments were discussed. Finally, the results were compared with those in references. 展开更多
关键词 high temperature SHPB experiment heat transfer thermal contact coefficient cold contact time
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