grads operator的用法和樣例：
例句
- The Hamiltonian of the system is the Driac operator which as a matrix differential operator is not semibounded from below.
系統的哈密頓函數是作為矩陣微分運算元的狄拉克運算元，它不是半有界的。 - The standard parabolic equation method was obtained by the decompocition of the scalar wave equation and the expansion of the pseudo-differential operator.
通過對傳統波動方程的分解和偽微分運算元的近似展開，獲得了標準拋物線方程。
