Therefore, the P-Q symbolmethod cannot only judges the out-of-step between the power systems, but also as early as identify the accurate time.
因此P-Q符号法能有效地识别系统之间的 失 步，而且能及早地判断出 失 步的时刻。
2
Rotation angle symbolmethod to identify circuit and branch of spherical four bar is presented in this paper. Finally, the method about application to spatial first group mechanism is elaborated.
最后由空间第一类机构与球面四杆机构的等效性，阐述了将此识别方法应用于第一组空间机构的方法。
3
These are method invocations, each taking a symbol as a single parameter.