bottomer井底把钓工bottomn.底部；底端adj.底部的v.触底；打(基础)bottom sealing machine封阳极机bottom of the bow wave弓形波的底部(波谷)bottom-end of stroke行程的下死点bottom bracket bearing中轴轴承bottom-up recognizer自底向上识别算法bottom plate of column分馏塔底塔盘bottom ripping machine巷道卧底机bottom pit engineering基坑工程bottom centrefired pit中心燃烧式均热炉bottom sediment dredge底泥疏浚