构件受弯时计算构件正应力的公式是()。
A.σ=M/W
B.σ=M/F
C.σ=M/E
D.σ=M/I
参考答案:A
Danny is tired, he walks _____ and _____. [ ]
A. slow, slow
B. more, more slowly
C. slower, slower
D. slowly, slowly
最适合作O/W型乳剂的乳化剂的HLB值是
A、HLB值在1~3
B、HLB值在3~8
C、HLB值在7~15
D、HLB值在9~13
E、HLB值在8~16