China is a typical country that is in serious lack of water. China's national economy of retainable development has been interfered by it.

我国是典型的贫水大国，缺水已严重制约我国国民经济的可持续发展。

Due to usual control methods making defects to retainable load system, fuzzy control with PWM is adopted, which has reached good control results.

针对常用控制方法对负荷保持系统产生的缺陷，采用模糊控制思想，利用PW M脉宽调制技术，达到了很好的控制效果。

The interchange of the optical fiber guide light needle and the needle core of a retainable needle are not needed when in use, and the blood efflux because of inexperienced operation can be avoided.

使用时无需进行光纤导光针与置留针针芯的互换，可避免因操作不熟练造成的血液外流。