To improve the performances of an electro-optical conversion device, a physical model of the same is needed. In fact, once an appropriate model is built, the optimization of the device design is possible. In particular, electrochemical properties are very relevant to the efficiency of electro-optical conversion devices. It has been shown that impurity doping is an effective method of improving electrochemical performance [1][2][3][4]. An Al-doping ternary cathode material model based on first principles density functional theory is proposed to improve the electrochemical performance of the device (Gao et al.). In this model, Al doping provides the ternary cathode material with better electrical conductivity and cycling ability, therefore results in a significant improvement in the rate performance of the material. On this basis, considering that Li-rich Mn-based oxides are also commonly used cathode materials for battery modules of electro-optical conversion devices, a similar model is established to simulate the effects of changing sodium doping amounts on the electrochemical properties of the oxide (Gao et al.). The results show that the conductivity is larger when the sodium doping amount is 0.1 mol. In addition, a model is developed to prepare n − -n + photodiodes by growing Bi-doped MAPbCl3 epitaxial layer on MAPbCl3 single crystal substrate (Zhao et al.). Specifically, impurity doping can improve the physical and electrochemical properties of conventional materials, leading to an increase in the efficiency of electro-optical conversion devices [5,6].At the same time, high self-heating and low heat dissipation are the critical issues needed to be addressed during the operation of electro-optical conversion devices. Heat is generated during devices operation, resulting in higher device temperature and thermal droop. Building some specific models to reduce the thermal droop can effectively boost the efficiency of the devices and promote the energy saving [7][8][9]. A model based on thermal transport effects is proposed to study electron transports and transport efficiency of LEDs under high and low bias voltages. When the applied voltage is lower than the photon voltage, heat generated in the circuit is exchanged and absorbed by carriers. This allows to improve the efficiency of the whole system through energy recovery and heat collection (Lu et al.). The new model can act as the research prototype to design high-efficient LED arrays for better energy recycling and thermal control. Based on the concept of heterostructure, a model is proposed to obtain a new type of nanowire (NW) photoanode by strong enhancement of the photocurrent in solar water splitting.

With the improvement of the level of the technology, the safety of aircraft has received more and more attention. In order to better monitor the aircraft safety, a Beidou-based aircraft safety monitoring system was designed. The main factors affecting the safety of the aircraft were obtained through cluster analysis. The system used BMP180, MPU9250 HS-FS01 and DHT11 to monitor the air pressure, altitude, attitude angle, acceleration, wind speed, temperature and humidity of the aircraft's position. It used the GPS/BDS dual-mode positioning module to accurately and timely synchronize the space and time of the aircraft, using the fuzzy analysis to comprehensively assess the safety status of the aircraft, using WIFI/GSM/GPRS switchable wireless network to send the acquired information to the PC monitoring software. The hardware and software design of the system are studied, and the test results are given. The results show that the system can accurately monitor the status information of the aircraft and comprehensively evaluate the safe working coefficient of the aircraft.