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Xu M.L.,National University of Defense Technology | Zhang G.Y.,National University of Defense Technology | Zhang G.Y.,Beijing Special Engineering Design Institute | Zhang R.Q.,National University of Defense Technology
Applied Mechanics and Materials

In this paper the NHDMOC method which succeeded in studying stress wave propagation with one dimensional strain was applied to study the one-dimensional stress wave propagation. In this paper, the ZWT nonlinear visco-elastic constitutive relationship with 7 parameters to NHDMOC, and corresponding equations were deduced The equations was verified from the comparison of elastic stress wave propagation in SHPB with elastic bar and visco-elastic bar respectively. Finally the dispersion and attenuation of stress wave in SHPB with visco-elastic bar was studied. © (2014) Trans Tech Publications, Switzerland. Source

Qi J.,National University of Defense Technology | Jiang P.,National University of Defense Technology | Guo B.,National University of Defense Technology | Wang D.,Beijing Special Engineering Design Institute
QR2MSE 2013 - Proceedings of 2013 International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering

For long-wait-short-run equipment, it is in the standby state with very short operating time during its lifetime. The performance degradation of this equipment depends on not only the accumulative operating time, but also the accumulative non-operating time. In this paper, the reliability model of the long-wait-short-run equipment is established based on Gamma process in which both the accumulative operating time and the accumulative non-operating time are treated as independent variables. The method to evaluate the reliability is also proposed. Finally, a numerical experiment is given and the result shows that the proposed method is proper to evaluate the reliability of the long-wait-short-run equipment. © 2013 IEEE. Source

Liu Q.-W.,CAS Institute of Software | Liu Q.-W.,University of Chinese Academy of Sciences | Cao Z.-S.,Beijing Special Engineering Design Institute | Zheng C.-W.,CAS Institute of Software | Hu X.-H.,CAS Institute of Software
Yuhang Xuebao/Journal of Astronautics

A new method using image series of monocular optical imaging system on motion platform for spacecraft orbit determination is developed in the absence of position or velocity information of target spacecraft. Through analysis of characteristics about the imaging system and space relation of the imaging system and the spacecraft, the concept on the real average angular velocity and the apparent average angular velocity is presented to design an equation in order to estimate slope distance of the imaging system according to longitude and latitude data derived from image series and to calculate spacecraft initial state parameters. This method offers an approach for orbit determination with series image from the monocular optical imaging system by coping with the problem to calculate the longitude and latitude according to image series and then to estimate the slope distance. Finally a simulation instance of a GEO satellite is adopted to validate this method. Source

Li Z.,Chinese Institute of Crustal Dynamics | Wang J.,Chinese Institute of Crustal Dynamics | Liu L.,Beijing Special Engineering Design Institute
2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010

Voice over Internet Protocol (VoIP) over a wireless local area network (WLAN) is poised to become an important Internet application. However, unacceptable VoIP performance in the presence of coexisting traffic from other applications is still one of the major problems standing in its development way. For this point, in this paper, a novel adapted adjustment packet segmentation method is proposed to promote the performance of VoIP which do not influence non-real-time application much. In this method we use the channel utilization to decide the segmentation's factor. This method is verified through simulations. ©2010 IEEE. Source

Hong X.,Beijing University of Posts and Telecommunications | Wu J.,Beijing University of Posts and Telecommunications | Zuo C.,Beijing Special Engineering Design Institute | Liu F.,Beijing University of Posts and Telecommunications | And 2 more authors.
Applied Optics

A distributed fiber optic vibration sensor is described, in which two Michelson interferometers are used as phase detectors and two 3 × 3 couplers are deployed to demodulate the time-varying phase change caused by vibration. The two interferometers are separated by four wavelength division multiplexers. The position of the vibration is obtained by signal correlation, which can be used as a perimeter security sensor to locate the intruder. The experimental results with a 4012mfiber sensor are discussed. © 2011 Optical Society of America. Source

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