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Zhang L.-Q.,Beijing University of Technology | Zhang L.-Q.,Center for Engineering Design and Research under the Headquarters of General Equipment | Deng Z.-C.,Beijing University of Technology | Shi J.,Beijing Jiaotong University | Guo F.-M.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2012

To study dynamic response of high-speed slide rail with track irregularity excitation, according to the vehicle dynamic and track dynamic theory, a sled-track dynamic analysis model of the high-speed track system is established. Sled-track dynamic responses under different speeds and irregularity excitations are analyzed and calculated. Effect on sled-track dynamic response by regularity of high-speed slide rail is discussed quantitatively. Results show that the peak vicissitude acceleration is up to 5.1 m/s 2 when the high-speed sled slides at the speed of 700 m/s. When the sliding speed is 700 m/s, the vibration acceleration of the sled is 8 times than that of 100 m/s. To avoid excessive vibration, the high-speed sled irregularity amplitude must be less than 2 mm. Source


Yang G.-L.,China University of Mining and Technology | Yang R.-S.,China University of Mining and Technology | Jiang L.-L.,Center for Engineering Design and Research under the Headquarters of General Equipment
Baozha Yu Chongji/Explosion and Shock Waves | Year: 2012

Simulations were performed to analyze the propagation and superposition processes of stress waves aiming to three different charge structures under top, bottom and simultaneous initiations, respectively. The pressure in the middle of the borehole increases greatly when increasing the top charge under top and simultaneous initiations. Adopting bottom initiation, the pressure peaks of stemming part are higher than those adopting the other two initiations. For three charge structures under bottom initiation, comparisons of the pressure curves along the boreholes display that more even-distributed pressure can be obtained and the corresponding mean pressure is higher by increasing the top charge. The simulated results were applied to the field practice and the big fragments were deleted basically. So the gangue backfill efficiency can increase by adopting air-deck charge blasting. Source


Chen H.,Center for Engineering Design and Research under the Headquarters of General Equipment | He S.,Huazhong University of Science and Technology | Chang H.,Huazhong University of Science and Technology | Shu S.,Huazhong University of Science and Technology
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2015

For the diving process, imcompressiable Navier-Stokes equations, together with phase field equation, were used to track the interface and flow characteristic which took into account buoyancy and evaporation of cryogenic liquid in water. The mathematical models were combined to predict the penetration depth and evaporation rate of cryogenic liquid in water. Numerical studies have been taken under the conditions of various of initial velocities and initial diameters of liquid nitrogen with these models. The results show that the diameters and the velocities have a great influence on penetration depth, cryogenic shape and evaporation rate. For the relatively small diameter, all liquid nitrogen evaporates in water and only vapor comes out of water. For the relatively large diameter, not all liquid nitrogen evaporates in water and some cryogenic liquid may come out of water. ©, 2015, Huazhong University of Science and Technology. All right reserved. Source


Wu X.,Center for Engineering Design and Research under the Headquarters of General Equipment | Wu X.,Naval Institute of Hydrographic Surveying and Charting | Zhang C.,University of Chinese Academy of Sciences | Wang K.,Zhengzhou University
Acta Geodaetica et Cartographica Sinica | Year: 2011

The basic equations for the solution of global point-mass model based on the complex combination and complete tensor components of global gravity gradient were studied and established in this paper, from which point-mass harmonic analysis solutions of single determined and over determined boundary value problems based on satellite gravity gradient were attained. The stability of point-mass harmonic analysis solutions was obtained via the decomposition of large linear equations using blocked cyclic matrices. Finally, simulation experiments with EGM 2008 were made to validate the validity and feasibility of point-mass harmonic analysis of satellite gravity gradient boundary value problems. Results indicate that with proper depths of the point masses, point-mass harmonic analysis could recover an earth gravity field model at a higher precision which is a little better than that from the generalized torus harmonic analysis. Source


Zhan Y.,Zhengzhou University | Zheng Y.,Zhengzhou University | Zhang C.,Zhengzhou University | Luo Y.,Zhengzhou University | Wang K.,Center for Engineering Design and Research under the Headquarters of General Equipment
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2016

A fish-eye camera calibration model is presented, basic observations of which consist of both half angle of view and azimuth. Rodrigues matrix is introduced into the model, and three Rodrigues parameters instead of Euler angles are used to represent elements of exterior orientation in order to simplify the expressions and calculations of observation equations. The new model is compared with the existing models based on half angle of view constraint by actual star-map data processing, and the results indicate that the model is superior to control the azimuth error, while slightly inferior to constrain the error of half angle of view. It is advised that radial distortion parameters should be determined by the model based on half angle of view constraint at first, and other camera parameters should be calculated by the new model. © 2016, Surveying and Mapping Press. All right reserved. Source

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