Nowadays, mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation, stroke, cerebral hemorrhage, large-scale cerebral infarction, and craniocerebral injury. In this paper, a locally mixed sub-low temperature device is designed, and the cold and hot water mixing experiment is used to simulate the human blood transfer process. To set a foundation for the optimization of the heat transfer system, the static characteristics are analyzed by building the mathematic model and setting up the experimental station. In addition, the affection of several key structure parameters is researched. Through experimental and simulation studies, it can be concluded that, firstly, the mathematical model proved to be effective. Secondly, the results of simulation experiments show that 14.52 °C refrigeration can reduce the original temperature of 33.42 °C to 32.02 °C, and the temperature of refrigerated blood rises to 18.64 °C, and the average error is about 0.3 °C. Thirdly, as the thermal conductivity of the vascular sheath increases, the efficiency of the heat exchange system also increases significantly. Finally, as the input cold blood flow rate increases, the mass increases and the temperature of the mixed blood temperature decreases. It provides a research basis for subsequent research on local fixed-point sub-low temperature control technology.

In order to process respiratory sounds to achieve acquiring available information of sound signals Empirical Mode Decomposition (EMD) and Wavelet Decomposition (WD) are applied separately to analyze lung sound signals. The de-noise of original signals is processed with spectral subtraction method. EMD divides the signal into independent Intrinsic Mode Functions (IMFs). Moreover, WD method decomposes the signal with wavelet transform. After receiving the decomposition signals of EMD and WD, a comparation is demonstrated. According to the results, WD has 85% signal information concentrate on layer 7 and Hilbert diagram shows the EMD owns more efficiency in decomposing signals with information keeping.

At high altitudes, the pilot is subject to a rapid loss of pressure in the case of cockpit rupture, when, the human body will possibly suffer from a sudden drop in air pressure, exposed to the risks of lung expansion, lung injury, and alveolar rupture. In this case, it is particularly important to control the oxygen supply system to avoid similar situations. Herein, a mathematical model of the human lung respiratory system and the oxygen supply system under pressure loss conditions is established based on aerodynamics by taking into account the dynamic model and nonlinear relationship, and the simulation of the oxygen supply system and the human respiratory system under pressure loss conditions is realized. Besides, the Aviation rapid decompression protection system (ARDPS) is hereby established and verified through experiments and simulations, which proves the efficiency of the experimental platform in effectively simulating the oxygen supply system and respiratory process in extreme environments of pressure loss. Finally, the entire model is controlled based on PID control and cascade PID control. A comparison of control effects is obtained, verifying the stronger anti-interference ability, faster control speed, and higher accuracy of cascade PID control compared to PID control in terms of voltage loss protection.

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