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Chen H.-K.,Chongqing Jiaotong University | Chen H.-K.,China Three gorge University | Tang H.-M.,Chongqing Jiaotong University | Wang Z.,Chongqing Jiaotong University | He X.-Y.,Chongqing Jiaotong University
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2014

The excitation effect of perilous rocks is one of main impact factors to induce the chain damage of unstable aggregation rock blocks. Aiming at a falling perilous rock, a laboratory model test for testing its excitation effect was conducted. The test results showed that firstly, the quality effectiveness of the excitation signals can be determined with the coherent coefficient analysis method, and almost all the measured excitation signals of unstable rock are distributed in a3 (0~1250Hz) frequency range; secondly, the time-history curve for each wavelet decomposition coefficient of an excitation signal can be gained with the db8 (3 layers)wavelet analysis method, and its spectrum figure can be obtained through Fourier transformation; thirdly, the excitation signal totally presents an attenuation trend, and it has three peak values at 900Hz, 1100Hz and 1500Hz; the larger the distance between a measured point and the fountainhead of an excitation signal, the bigger the excitation acceleration, and the excitation acceleration in the vertical direction is bigger than that in the horizontal direction; fourthly, the better the integrality of interface between two perilous rocks, the easier the transfer of excitation signals, and the decay rate in the vertical direction is higher than that in the horizontaly direction. The results had a positive effect on revealing the damage mechanism of group-occuring unstable rock blocks. Source


Li D.,Chongqing Three Gorges University | Li H.,China Three gorge University
Advanced Materials Research | Year: 2012

In this paper, an efficient algorithm for computing 10-point DFT, radix-10 FFT algorithm for computing 10 M-point DFT and N=L×10 M-point DFT are presented. FFT is often employed in power systems harmonics analysis even though it is not accurate due to spectral leakage and barrier effect. When N=L×10 M-point DFTs are used to analyze harmonics in power systems, comparing to N=2 M-point DFTs, very accurate harmonic parameters can be obtained. The simulation results in MATLAB show that the methods are feasible and effective to enhance analysis accuracy. © (2012) Trans Tech Publications, Switzerland. Source


Zeng T.-L.,Chongqing University | Wen Z.-Y.,Chongqing University | Wen Z.-Q.,Chongqing University | Zhang Z.-W.,Chongqing University | Wei K.-L.,China Three gorge University
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

The water quality monitoring technology based on ultraviolet spectrum analysis has the characteristics of small volume, low cost, and no secondary pollution, and it doesn't need any reagent and sample pretreatment. On account of these characteristics, the direct ultra-violet technology has remarkable superiority over traditional technologies when applied in online monitoring of drinking water, surface water and industrial wastewater, and it has become an important development tendency of modern water monitoring technologies. The principle, characteristics, present situation and development trend of modern water quality monitoring technology based on ultra-violet spectrum analysis were introduced, and the key technical problems were further discussed in this paper. Source


Li H.,China Three gorge University | Fei R.,Chongqing Three Gorges University
Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010 | Year: 2010

An efficient algorithm for computing 10-point DFT, which can contribute fast algorithms to more N-point DFTs, is developed. The computation of one 10-point DFT requires only 20 real multiplications, 84 real additions and 4 real right-shiftings 2 bits. According to the principles of decimation-in-time (DIT) or decimation-in-frequency (DIF) or double factors algorithm and the efficient algorithm of 10-point DFT, 10M, 10×M, 2M×10, 4M×10-point DFT have their own efficient algorithms, respectively. Thus, many N-point DFTs are possessed of own fast fourier transform algorithms. Especially, in efficient algorithm for computing 10-point DFT, in other words, in radix-10 FFT algorithm, one 102-point DFT requires 720 real multiplications, 1840 real additions and 80 real right-shiftings, one 103-point DFT requires 12760 real multiplications, 28580 real additions and 1200 real right-shiftings 2 bits, and one 104-point DFT requires 183560 real multiplications, 387780 real additions and 16000 real right-shiftings 2 bits. © 2010 IEEE. Source


Zhang Z.-W.,Chongqing University | Wen Z.-Y.,Chongqing University | Zeng T.-L.,Chongqing University | Wei K.-L.,China Three gorge University | Liang Y.-Q.,Chongqing University
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

The method based on miniature near-infrared spectrometer combined with Y fiber optic probe to detect the protein and fat in milk powder by diffuse reflectance spectroscopy in the wavelength range of 900~1700 nm was proposed. By selecting the appropriate spectral bands, the correction models of protein and fat were established with partial least squares algorithm using Unscrambler 9.7 Chemometrics software. The determination coefficients R2 of the correction modes are 0.987 and 0.986 for protein and fat respectively, and the root mean square errors RMSEC are 0.385 and 0.419 respectively. Using these correction models to predict the protein and fat contents with 30 sets of forecast sample data, the prediction standard deviation is SEPProtein=0.751 for protein, and is SEPFat=1.109 for fat. The results indicate that these correction models have prediction capability with unknown samples and meet the on line requirements. Source

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