There are two critical values for outer radius of the inner annular zone, at which focal spot changes sharply.The tunable range of the focal depth is very considerably.是什么意思_There are two critical values for outer radius of the inner annular zone, at which focal spot changes sharply.The tunable range of the focal depth is very considerably.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句