从Q=KAΔt可见,为了传递一定的热量,可以()以节省传热面积。
A.降低温度差
B.采用有相变的热载体,防止结垢
C.减少管内流体的滞留程度
D.减少管外流体的滞留程度
参考答案:B
已知抛物线y=-x2+2x+3的顶点为P,与x轴的两个交点为A,B,那么△ABP的面积等于______.
Thomas Edison considered genius to be _____ one per cent inspiration and ninety-nine percent perspiration.
A.composed of
B.constituted in
C.consisted of
D.comprised in