The upper bands (or buckets) in good lasing materials such as gallium arsenide are narrow and have steep sides, so they tend to hold relatively few electrons.是什么意思_The upper bands (or buckets) in good lasing materials such as gallium arsenide are narrow and have steep sides, so they tend to hold relatively few electrons.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句