upstream-downstreamCOCA³¹⁵¹¹¹⁺⁴BNC¹⁷³⁹⁹⁵⁺² 例句 The investigation of the upstream-downstream intermittent reversing flow in the near wall of a 2-D channel is attempted with a2- D laser doppler velocimeter LDV. 本文应用二维激光多普勒测速仪 LDV，对二元通道内近壁间歇性反流特征做了尝试性测量。 cnki