控制如何从粒子系统中移除粒子。
| Disabled | 当粒子的存活时间超过它们的生命周期时，将移除粒子。 |
| PauseUntilReplaced | Particle ages pause at the end of their lifetime until they need to be removed. Particles are removed when creating new particles would exceed the Max Particles property. |
| LoopUntilReplaced | Particle ages loop until they need to be removed. Particles are removed when creating new particles would exceed the Max Particles property. |