IRB=industrial reference black 工业基准黑IRabbr.信息检索(=information retrieval)irrigation and drainage农田水利irrotational flow model无旋流模型Irrigating source water农灌水irradiated nuclear fuel辐照过的核燃料irredeemable securities不偿还本金的证券irrigation pipe coupler灌溉水管接头irrigation water amount灌水量irradiative degradation辐照降解IR radiance calibration辐射定标irrecoverable losses.无法挽回的损失