A.Continue you walking
B.Keep going straight
C.Go along
D.Go on walking
Visitor:How do I get to the bank?I have no knowledge of this area.
Policeman:.Cross the road and turn left at the other side.For about l00
meters,the bank iS to your left.
A.Continue you walking
B.Keep going straight
C.Go along
D.Go on walking
A.60%—80%全年收入60%-80%thunhậpngười/năm
B.40%—60%全年收入40%—60%thunhậpngười/năm
C.依法给予规定上限giớihạnquyđịnhtheoluật
有一普通圆柱蜗杆传动,已知蜗杆头数z1=1,分度圆直径d1=50mm,蜗轮齿数z2=40,模数m=5mm,当量摩擦因数f'=0.09,试求:
(1)传动比i及传动中心距a;
(2)判断该传动是否自锁;
(3)蜗杆、蜗轮分别为主动件时的效率η及η'。
自由基聚合遵循规律,在某一引发剂起始浓度、单体浓度和反应时问下的转化率如下表:
试验 | T/℃ | [M]/(mol·L-1) | [I]×103/(mol·L-1) | 聚合时间/min | 转化率/% |
1 | 60 | 1.00 | 2.5 | 500 | 50 |
2 | 80 | 0.50 | 1.0 | 700 | 75 |
3 | 60 | 0.80 | 1.0 | 600 | 40 |
4 | 60 | 0.25 | 10.0 | ? | 50 |
试计算实验4达到50%转化率时所需的时间,计算总活化能。