The length of the face determined by the distance of separation of jaws. The reference mark are nasospinale and chin point .The distance of these two marks is VD.

临上，面下部垂直距离的参考标志点一般用鼻下点和颏下点，这两点分别位于口裂的上、下方。

VD and working procedure.Experiments showed that major of the LF step foreign inclusions are aluminium sesquioxide. spotted non-deforming inclusion and sulphuret.

VD及成材工序场取样.系统分析了各工序中夹杂物的行为.特征.数量.变化历程及影响因素.实验结果表明.

Objective To observe the effect of electropuncture on mouse's jumping experiment of synthetic VD learning dysmnesia.

目的观察电血管性痴呆小鼠学习记忆障碍的影响。