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Jiang B.,Mechanical Engineering College | Qi X.-L.,Mechanical Engineering College | Liu J.,Armed Police Engineering University | Jia B.,Military Representative Bureau
Sensors and Transducers | Year: 2014

To meet the pressure sensors used in special harsh environments, the MEMS piezoresistive pressure sensor design is proposed that the technology is more mature and more extensive used. The research of Piezoresistive sensor chip is done based on the analysis of sensor principle. The chip substrate material is selected combine with the special environment. The range sensor chip design is done based on small deflection theory and silicon material diaphragm piezoresistive effect theory. In order to avoid resonance modal analysis of the diaphragm is done. The force-sensitive resistor strip and its layout in the diaphragm is designed combine with the round diaphragm stress distribution. Semi-open-loop mode bridge is choice based on the comparison of advantages and disadvantages of three bridge modes. Given the special environment of vibration, acceleration sensitivity calculations must be done to adapt vibration environments for pressure sensor. Theory basis in sensor design is full, design projects and parameters combine with special environmental closely, and the research will have important significance for further study of special environmental pressure sensor. © 2014 IFSA Publishing, S. L. Source

Wu Z.-W.,Armed Police Engineering University | Cheng P.,Beijing University of Technology | Fu H.-G.,Beijing University of Technology
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

Effects of quenching temperature on microstructure and mechanical properties of Fe-Cr-B-Al alloy containing 8%Cr, 1.5%B and 1.5%Al were investigated in the condition of oil-cooling quenching. The results show that the microstructure of as-cast Fe-Cr-B-Al alloy is consist of M2(B, C) (M=Fe, Cr, Mn), (Cr, Fe)7(C, B)3, martensite and pearlite. After quenching, the network eutectic borocarbides are broken and spheroidized, which lead to the increase of tensile strength and impact toughness of Fe-Cr-B-Al alloy. When quenching temperature exceedes 950°C, the matrix is transformed into martensite from the mixture of martensite and pearlite, and hardness of Fe-Cr-B-Al alloy increases. When quenching temperature is over 1050°C, borocarbides begin to coarsen. Fe-Cr-B-Al alloy quenched at 1050°C has good comprehensive properties. Source

Luo L.,Armed Police Engineering University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

For the purpose of monitoring the attitude of aircraft, an angular measurement system using a MEMS heat convection accelerometer is presented in this study. A double layers conditioning circuit that center around the single chip processor is designed and built. Professional display software with the RS232 standard is used to communicate between the sensor and the computer. Calibration experiments were carried out to characterize the measuring system with the range of - 90°to +90°The curves keep good linearity with the practical angle. The maximum deviation occurs at the 90°where the value is 2.8°.The maximum error is 1.6% and the repeatability is measured to be 2.1%.Experiments proved that the developed measurement system is capable of measuring attitude angle. © 2014 SPIE. Source

Wu Q.,Armed Police Engineering University | Lu J.,68036 PLA Troops
Lecture Notes in Electrical Engineering | Year: 2016

To resolve the security problem existing in multilayer and multi-domain intelligent optical network, the multilevel and expansive security architecture was presented based on the classified description of threats, and the design of the syncretic mechanisms. Finally, the security model is described by a mathematical model based on hypergraph theory. That is, the edges represent security level; nodes represent the corresponding security technology. The proposed model simplified the complexity of security architecture and facilitated the analysis of future quantitative mathematical. © Springer India 2016. Source

Liu J.,Xian University of Technology | Zhou F.,Xian University of Technology | Liu F.,Xian University of Technology | Liu F.,Armed Police Engineering University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2016

In order to ensure the high-efficiency and stable operation of the wind turbines, this paper presents compensation torque of fuzzy variable gain in torque control. The influence of mechanical torque fluctuation of wind turbines caused by random dither component of the tower shadow effect, wind shear, wind speed and reference rotation fluctuation calculated via optimal tip speed ratio on permanent magnet synchronous wind power system is alleviated effectively, the low frequency oscillation of wind power system is suppressed, and the stability of the system is ensured. It calculates accurate reference speed of maximum electromagnetic power by modifying the optimal tip speed ratio, and makes the unit run at the corresponding working point of maximum electromagnetic power. It truly achieves the maximum wind power tracking, by calculating the optimal tip speed ratio, considering the shafting friction loss. A direct-driven permanent magnet synchronous wind power system simulation platform is built in detail under Matlab/Simulink, and the correctness and effectiveness of the method is proved. © 2016, Power System Protection and Control Press. All right reserved. Source

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