Development of standard defibrillation energy source / 医疗卫生装备

To develop a standard defibrillation energy source which can output monophasic and biphasic de-fibrillation impulses and can display standard energy values. The storage capacitor was charged by single-end flyback transformator and discharged through the H bridge composed of insulated gate bipolar transistor (IGBT). Impulse voltage and current were collected by divider while discharging, and the energy value was calculated by STM32. The en-ergy value and waveform were displayed through the control module. The energy source could output both monophsic and biphasic waveforms, and the accuracy of displayed value was higher than ±2% or ±1 J. The standard defibrillation energy source can be used as standard device for defibrillator analyzer, and the metrological trace-ability system of defibrillation energy may come to be completed.

Testing method of human body's current threshold for perception based on EEG analysis / 生物医学工程学杂志

Electric and electronic products are required to pass through the certification on electrical safety performance before entering into the market in order to reduce electrical shock and electrical fire so as to protect the safety of people and property. The leakage current is the most important factor in testing the electrical safety performance and the test theory is based on the perception current effect and threshold. The traditional method testing the current threshold for perception only depends on the sensing of the human body and is affected by psychological factors. Some authors filter the effect of subjective sensation by using physiological and psychological statistical algorithm in recent years and the reliability and consistency of the experiment data are improved. We established an experiment system of testing the human hody's current threshold for perception based on EEG feature analysis, and obtained 967 groups of data. We used wavelet packet analysis to detect a wave from EEG, and used FFT to do spectral analysis on alpha wave before and after the current flew through the human body. The study has shown that about 97.72% alpha wave energy changes significantly when electrical stimulation occurs. It is well proved that when the EEG feature identification is applied to test the human body current threshold for perception, and meanwhile alpha wave energy change and human body sensing are used together to confirm if the current flowing through the human body reaches the perception threshold, the measurement of the human body current threshold for perception could be carried out objectively and accurately.