The diagnosis of sleep apnea syndrome (SAS) has important clinical significance for the prevention of hypertension, coronary heart disease, arrhythmias, stroke and other diseases. In this paper, a novel method for the detection of SAS based on single-lead Electrocardiogram (ECG) signal was proposed. Firstly, the R-peak points of ECG recordings were pre-detected to calculate RR interval series and ECG-derived respiratory signal (EDR). Then 40 time- and spectral-domain features were extracted and normalized. Finally, support vector machine (SVM) was employed to these features as a classifier to detect SAS events. The performance of the presented method was evaluated using the MIT-BIH Apnea-ECG database, results show that an accuracy of 95% in train sets and an accuracy of 88% in test sets are achievable.

Pain monitoring is essential during general anesthesia operations. Previous researchers have found relationship between pulse wave and painful stimulation and introduced parameters based on photoplethysmography (PPG). According to arterial windkessel model, pulse wave transfer function (PWTF) would represent the transmission of stimulation but there was little research on this. A synchronous dual channel PPG acquiring system with ECG circuit and external blood pressure module is built to push on the research. System works well with testers aged from 10 to 65, both male and female.

An instrument is proposed for nitrate in situ monitoring in deep sea. It consists of a UV spectrophotometer, a deuterium lamp of high stability and low power consumption, a rugged and high-throughput retro-reflection probe and a center control board with large data storage capacity. With a measurement precision of nitrate concentration of 1μmol/l and a resolution of 0.5μmol/l, the instrument is able to measure nitrate concentrations from 0.5μmol/l to 320μmol/l. The system can automatically deduct the dark current to rectify the effect of temperature drift and correct the overall absorbance drift caused by instrument drift through integration of relative absorbance (IRA) algorithm. The system can endure the pressure at up to 1500m deep sea and carry out automatic long-term in situ detection of nitrate with high stability without needs for any manual intervention.

As a major indicator in marine life research and geochemistry, the in-situ monitoring of dissolved oxygen has become increasingly important in the assessment of marine ecosystem. It has been proved that fluorescence quenching may result in shorter fluorescence lifetime. Based on it, this paper proposes an in-situ dissolved oxygen monitoring system of high precision and low power consumption applicable to long-term monitoring of complex marine environment. Using phase detecting method, an AC analog amplification channel on Precision photoelectric detection, and used digital phase detection method and three order integral average method to detect the phase offset. The ultralow-power microcontroller was used to control system. The experiments results show that the system has high stability, high precision(0.02mg/L), quick response time(≤40s), low power consumption(peak current ≤10mA), strong anti interference ability.

As a major indicator of Obstructive Sleep Apnea Syndrome (OSAS) in clinical diagnosis, the monitoring of sleep apnea plays an important role in medical treatments of modern society. This paper proposes a portable sleep apnea monitoring system, which is of high-precision and low-power consumption, and capable of performing the long-term monitoring of OSAS patients multiple physiological parameters in clinical treatments. In the system, the AC modulated detection is adopted, and low amplification ratios are utilized in forestage and a high-resolution AD converter is designed in post-stages. Thus, it is able to acquire, analyze, and process physiological signals in real-time. In addition, ultralow-power chips are used in control system to save the power consumption. The experimental results show that our monitoring system has the strengths of high stability, low-power consumption (peak current90mA), and strong anti-interference ability, which demonstrates the potential in practical applications.