超導(dǎo)和低溫
一般材料(除半導(dǎo)體以外)的電阻隨溫度降低而減小,當(dāng)溫度降得很低時,某些材料的電阻會完全消失,這種現(xiàn)象稱為超導(dǎo)性。出現(xiàn)超導(dǎo)性的這個最高溫度稱為該材料的超導(dǎo)臨界溫度。超導(dǎo)性的發(fā)現(xiàn)為電的利用打開了一個新大地;貫殡娮铻榱,只要施加一個很小的電壓就可以產(chǎn)生十分巨大(理論上是無限大)的電流,獲得巨大的磁場和磁力;或者當(dāng)電流通過它時,不發(fā)生電壓的降低和電能的損耗。顯然它的實際應(yīng)用將會引起人類在生產(chǎn)和生活上的變革,很受人們的關(guān)注。
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