标定比 nominal aspect ratio: 名义高宽比nominal compression ratio: 标称压缩比; 额定压缩率nominal focal ratio: 标称焦比; 标称焦距比nominal maximum reduction ratio: 额定最大破碎比; 最大公称破碎比nominal pitch ratio: 标称螺距比; 标称螺距直径比; 公称螺距比下载手机词典可随时随地查词查翻译