Papers by Author: Ji Wen Tan

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Authors: Wei Xia Zhan, Ji Wen Tan, Yan Wen
Abstract: In order to suppress the noise in the magnetic flux leakage, the algorithm considering signal correlation, in which an optimal predictor and an optimal updater were chosen for every sample at all scales according to the magnitude of the correlation coefficient, was proposed. So the wavelets obtained through designing predictor and updater can perfectly fit the local features of signal. The actually processing effect of the simulation and the magnetic flux leakage signal of damage in wire rope show that the proposed method, compared with the classical wavelet, can effectively remove noise in original signal and principally retain the local features of the original signal.
2652
Authors: Wei Xia Zhan, Ji Wen Tan, Yan Wen
Abstract: In order to remove noise in the broken wire signal of wire rope, a new denoising algorithm based on the correlation of inter scales wavelet coefficient was proposed. Because the wavelet coefficient of signal has strong correlation and the wavelet coefficient of noise does not has obvious correlation, in the process of calculating threshold, an inter scales correlation factor was constructed considering the part specialty of next scale on the same position after wavelet transform. The proposed factor can adaptively adjust threshold on the position of signal and noise, thereby otaining good denoising effect and holding the break information in original signal. The actual processing effect of simulation and damage signal of wire rope shows that the proposed method, compared with the classical threshold, not only effectively removes noise in original signal and improve the signal noise ratio(SNR),but also retains the break information of inspected damage signal of wire rope.
2027
Authors: Hai Tao Wang, Ji Wen Tan, Zhong Chu, Chun Yan Sheng
Abstract: Proper content of titanium, microalloying in steel ZG200-400 smelted in intermediate frequency induction furnace, could effectively increase the volume of concentrated shrinkage cavity, and restrain the forming of shrinkage porosity. The concentrated shrinkage cavity was analyzed quantitatively by stuffing wet gluten and draining water method. The maximal cavity arrived at 0.18wt.% titanium microalloying. By scanning electron microscope (SEM) and energy disperse spectroscope (EDS) analysis, it was found that TiC, acting as heterogeneous nuclei, could refine the structure grains, diminish the strong dendrites, and increase the fluidity and feeding capacity of steel liquid. However, overdoes titanium microalloying easily caused mass nitrides or oxides, which kept solid phases with high meting point in metal liquid to increase its viscosity, decrease the fluidity and enlarged the composition supercooling. So the metal liquid, with poor feeding, left more shrinkage porosity, less concentrated shrinkage cavity in solidification.
795
Authors: Guang Yao Meng, Ji Wen Tan, Yi Cui
Abstract: Relative motion between grinding wheel and workpiece makes the lubricant film pressure formed by grinding fluid in the grinding area increase, consequently, dynamic pressure lubrication forms. The grinding fluid flow field mathematical model in smooth grinding area is established based on lubrication theory. The dynamic pressure of grinding fluid field, flow velocity and carrying capacity of lubricating film are calculated by the numerical analysis method. An analysis of effect of grinding fluid hydrodynamic on the total lifting force is performed, and the results are obtained.
948
Authors: Hai Tao Wang, Ji Wen Tan, Zhong Chu, Hua Shun Yu
Abstract: The effects of titanium modification, which was added along with the pouring liquid in ladles, on the hardness and its distribution of cast steel ZG45 smelted in intermediate frequency induction furnace were studied. Titanium modification increased the hardness of cast steel effectively. By scanning electron microscope (SEM) and energy disperse spectroscope (EDS) analysis, it was found that TiC, acting as heterogeneous nuclei, could refine the structure grains, causing the serious crystallographic lattice distortion. So the hardness increased. Proper content of titanium prompted more even hardness distribution across the whole temperature front section. However, overdoes titanium modification easily caused mass nitrides or oxides, which kept solid phases with high meting point in metal liquid to cause difficulties in metal liquid filling and shrinkage, resulting in less concentrated shrinkage cavity and serious structure rarefaction. The hardness ratio between that of internal and external with overdose titanium modification decreased instead compared to that of none modification.
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