With the invention of high-temperature-superconductor, the superconductive magnetic gradiometer be-comes available in application.

由于导体研究成功，使得导磁梯度仪际应用成为现。

Gravity gradient is the second order derivative of gravitational potential, which can be observed by satellite gradiometer.

摘要重力梯度为重力阶导数，可以通过星载梯度仪进行观测。