砂质的

In-house development and research is an effective and efficient way forward, said Professor Frances Gotch, one of the commentary's authors from the Division of Investigative Science at Imperial College.

世界已不再需要或不能接受这种老套的机制。本地开发和研究才是一种高效便捷的未来方式。

The general formula to calculate the rotating surface area which is shaped by rotating the curve c in xoy plane around the L-axis by using curve integral.

依据所证得的通用计算公式推证得到，在某些特定情形下利用定积分计算旋转曲面面积的具有针对性的公式。