下闸首 meaning in Chinese

lower head

At the same time , figures involving attribute data about flow field at inlet and outlet downstream or wave motion of water at the downflow head of lock chamber of siyang navigation lock were displayed through gis application system which we developed . according to data of baoying navigation lock acquired by mathematics model , figures about velocities which have the same value , velocities toward cross direction which have the same value and flow field at inlet and outlet upstream were formed . achievement data , space information and attribute information were in connection with figure so as to search for and analysis the information , which is satisfying
同时完成了江苏泗阳船闸下游引航道非恒定流及其改善措施的计算分析研究和宝应船闸上游引航道口门区水流条件计算分析研究，运用gis技术和所设计的gis应用系统对泗阳船闸下游引航道内流场以及下闸首水位波动情况进行信息显示，根据对宝应船闸的计算结果生成上游引航道口门区等流速图、横向流速等值线图和流场图，使计算分析成果数据、空间信息、属性信息与图形显示有机结合，便于查询分析，效果令人满意。