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Qian Y.,Northern University for Nationalities
2010 International Conference on Multimedia Technology, ICMT 2010 | Year: 2010

this paper presents an improved threshold function in order to improve the effect of electro-cardio signal denoising. This improved threshold function is continuous; the wavelet coefficients are reduced to zero smoothly according to the function when their absolute values are less than threshold value. Adding a factor to the function can change the form of threshold function and adjust the estimated deviation of wavelet coefficients. The results of MATLAB simulation show that the denoising effect of this method is better than soft and hard threshold. It may help to improve the quality of diagnosis if this method is applied to electro-cardio signal pre-processing, and it can be applied in communication systems for speech signal denoising. ©2010 IEEE. Source


Pei Z.,Hebei University of Engineering | Du J.,Northern University for Nationalities | Gao X.,Hebei University of Engineering | Lei Y.,Peking University | Li P.,Hebei University of Engineering
Journal of Nanoscience and Nanotechnology | Year: 2014

Three porous structures of ZnO were successfully synthesized in mixed solvents of ethylene glycol and distilled water. By adjusting ratios of ethylene glycol and distilled water, ZnO morphologies changed. Small porous plates with different sizes, folded porous plates with well-proportioned pores, heavily folded porous plates and solid flowers without pores emerged in sequence. The mechanism of the synthetic process was discussed. The morphologies and microstructures were investigated by transmission electron microscopy (TEM). The phase composition was verified by X-ray diffraction (XRD). This synthetic route provides a new idea to prepare other new structure materials. Copyright © 2014 American Scientific Publishers. Source


Pei Z.,Hebei University of Engineering | Du J.,Northern University for Nationalities | Gao X.,Hebei University of Engineering
Journal of Nanoscience and Nanotechnology | Year: 2014

0.6 to 7.5 μm LiMnPO4 porous plates with pore sizes from 100 to 150 nm were successfully synthesized in mixed solvents of ethylene glycol and distilled water. By changing stirring time, different morphologies of LiMnPO4 were prepared. Porous plates with the percentages of more than 70%, more than 50% and 25% porous ones were formed in sequence. The according rest parts were particles, less than 40% solid plates and 25% solid ones, respectively. Stirring time is the key cause influencing the nucleation rate and diffusion rate of the initial formed growth units of LiMnPO 4. Through adjusting the factor, chemicals with specific morphology can be obtained in mixed solvents. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. This synthetic route provides us a new idea to prepare new structure materials. Copyright © 2014 American Scientific Publishers. Source


Wang T.,Northern University for Nationalities | Tian Z.-F.,Fudan University | Ge Y.-B.,Ningxia University
Shuidonglixue Yanjiu yu Jinzhan/Chinese Journal of Hydrodynamics Ser. A | Year: 2011

A high order compact upwind scheme was developed for solving convection diffusion equation with source term. The schemewas applied to solve the governing equations that describe binary fluid mixtures convection systems. The convection terms were discretized with fourth order compact upwind finite difference schemes and the viscous terms were discretized with fourth order accurate symmetrical compact finite difference schemes. Numerical simulations of the traveling wave convection patterns in fluid mixtures inside a large rectangular chamber with an aspect ratio Γ=46 were performed. Counter-propagating waves and two types of modulated traveling wave were obtained. The results are in good agreement with those obtained by other scholars, which proves the validity of the present method. Besides, extend traveling waves were obtained by further computation. Based on above, the dependence of the localized traveling wave on Rayleigh number and the stability of localized traveling wave exists with the range of r=1.12-1.22 were discussed. Source


Wang J.-G.,Yunnan Agricultural University | Gao Q.-C.,China University of Mining and Technology | Lu H.,Northern University for Nationalities | Liang S.-F.,China University of Mining and Technology | And 2 more authors.
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

Using SHPB test device, a test method used in layered medium dynamic performance study and data analysis was established. By adjusting bullet speeds and testing repeatedly, the varyings of stress and strain of hard-soft layered medium composed of C30 concrete and foam concrete versus time under impact loading were measured. The test results showed that the plastic property of the hard-soft layered medium is much stronger than that of hard material; the elastic modulus of the hard-soft layered medium decreases gradually with increase in stress and strain, the energy absorption action of soft material can effectively protect hard material, so the hard-soft layered medium has a good ability of anti-high speed shock and anti-shock wave propagation. ©, 2015, Chinese Vibration Engineering Society. All right reserved. Source

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