backmen后卫backn.后面；背脊；靠背；后背；后卫vt.支持；后退adv.向后地adj.向后的；后面的；偏远的；过时的；积欠的back-biased silicon diode反向偏置硅二极管,反向偏压硅二极管backscattering spectroscopy背散射光谱法backflushing chromatography反冲层析backscattering spectrometer反向散射能谱仪backscatter cross-section散射截面back-hoe front end loader后挖前卸式挖装机back-forward sweep method前推回代法back-arc spreading center弧后扩张中心Back-up Intercept Control备用截击指挥系统back scattering coefficient[电] 反向散射系数