【简答题】混凝土的水灰比W/C和相应的28d抗压强度f 28 试验数据列于下表,试确定f 28 —C/W的经验公式,并计算其相关系数。 编号 水灰比 W/C 灰水比 C/W 28d抗压强度 f 28 (MPa) 1 0.40 2.500 36.3 2 0.45 2.222 35.3 3 0.50 2.000 28.2 4 0.55 1.818 24.0 5 0.60 1.677 23.0 6 0.65 1....
【判断题】卡莫司汀是1,4-二经基-5,8-双[[2-[(2-经乙基)氨基]乙基]氨基]-9,10-蒽醌
【单选题】4只纯电阻的用电器其额定电压和额定功率分别列于下面,其用电器电阻最大的是()。
【单选题】8位二进制补码1111 1111表示的实际数字是?
【单选题】8位二进制补码1111 1110表示的实际数字是?
【简答题】______下形w周的长度叫做这w下形的周长.
【简答题】简述在车辆导航系统中,与数字地图相关的功能有哪些?
【单选题】The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a pilot...
A.
enormous wingspan of the pterosaurs enabled them to fly great distances
B.
structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats
C.
fossil remains of the pterosaurs reveal how they solved the problem of powered flight
D.
pterosaurs were reptiles
【简答题】(下0w下?五河县模拟)一个圆锥形的沙堆,量得底面周长是w下.46米,高是w.下米,u果每立方米沙重w.4吨,这堆沙重多少吨?(得数保留一位小数)