active high signal的用法和样例：
- Most of them was low or equal signal on T1WI,high signal on T2WI.
- A T/H stage is added in the front for high signal bandwidth.
- When a No.3 Or Higher Signal is Issued.
- The strategies to promote heterolytic cleavage of hydrogen peroxide to facilitate the formation of active high valent metal-oxo species were discussed in details.