直径为d的半圆截面,其形心c的坐标yc=2d/3π。则静面矩Sx1为()。
A.A
B.B
C.C
D.D
参考答案:A
解析:
根据合力之矩定理
[*]
脉压增大主要见于()
A.主动脉瓣关闭不全
B.甲亢
C.主动脉瓣狭窄
D.动脉导管未闭
E.心力衰竭
In HDLC protocol, when supervisory frame's type code is '00'. About the following state-ments, which is correct ( )
A.receive ready
B.receive not ready
C.reject
D.selective reject