First, the pulse repetition frequency.
The pulse repetition frequency, that is, the number of pulses transmitted per second, is the reciprocal of the pulse repetition interval PRI. The pulse repetition interval is the time interval between one pulse and the next. If the pulse sequence is regular and the pulses are coherent, then it is a frequency comb in the frequency spectrum (or spectrum), and the comb tooth spacing of the frequency comb is the repetition frequency. The jitter relative to the ideal periodic pulse sequence is called timing jitter.
The repetition frequency of pulse train with different generation methods is very different. The main pulse generation modes and corresponding repetition frequencies are as follows:
1. The repetition frequency of a typical solid-state mode-locked laser is usually 50MHz to several GHz, and in a few cases it can be lower than 10MHz or as high as 100 GHz.
2. The repetition frequency of the solid-state Q-switched mode-locked laser can range from less than 1Hz to 100 kHz.
3. The repetition frequency of gain-switched semiconductor lasers ranges from less than 1Hz to several MHz.
4. The repetition frequency of finite-length attosecond pulse sequence generated by higher harmonics can be as high as hundreds of THz.
Second, fibrin rich in platelets.
Uses: At present, it has been widely used in stomatology, maxillofacial surgery, orthopedics, plastic surgery and so on. In the past, it was mainly prepared as a membrane for wound repair. Some scholars have studied that the prepared PRF gel is mixed with autologous fat particles in a certain proportion and applied to autologous fat transplantation such as autologous fat breast augmentation to improve the survival rate of autologous fat.