chen lu | Havard - Academia.edu (original) (raw)
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Centre for Energy Research, Eötvös Loránd Research Network
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Papers by chen lu
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1994
The damaging effect of mono- and diatomic phosphorus and arsenic ions implanted into silicon was ... more The damaging effect of mono- and diatomic phosphorus and arsenic ions implanted into silicon was investigated by spectroscopic ellipsometry (SE) and high-depth-resolution Rutherford backscattering and channeling techniques. A comparison was made between the two methods to check the capability of ellipsometry to examine the damage formed by room temperature implantation into silicon. For the analysis of the spectroscopic ellipsometry data we used the conventional method of assuming appropriate optical models and fitting the model parameters (layer thicknesses and volume fractions of the amorphous silicon component in the layers) by linear regression. The depth dependence of the damage was determined by both methods. It was revealed that SE can be used to investigate the radiation damage of semiconductors together with appropriate optical model construction which can be supported or independently checked by the channeling method. However, in case of low level damage (consisting mainly of isolated point defects) ellipsometry can give false results, overestimating the damage using inappropriate dielectric functions. In that case checking by other methods like channeling is desirable.
2009 8th International Conference on Reliability, Maintainability and Safety, 2009
ABSTRACT De-noising and extraction of the weak signature are crucial to fault diagnostics in whic... more ABSTRACT De-noising and extraction of the weak signature are crucial to fault diagnostics in which case features are often very weak and masked by noise. The wavelet transform has been widely used in signal de-noising due to its extraordinary time-frequency representation capability. In this paper, wavelet decomposition-based de-noising method is employed for fault feature extraction of hydraulic pump. The experiment result reveals that the wavelet decomposition de-noising method can achieve satisfactory results on weak signal detection of hydraulic pump.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1994
The damaging effect of mono- and diatomic phosphorus and arsenic ions implanted into silicon was ... more The damaging effect of mono- and diatomic phosphorus and arsenic ions implanted into silicon was investigated by spectroscopic ellipsometry (SE) and high-depth-resolution Rutherford backscattering and channeling techniques. A comparison was made between the two methods to check the capability of ellipsometry to examine the damage formed by room temperature implantation into silicon. For the analysis of the spectroscopic ellipsometry data we used the conventional method of assuming appropriate optical models and fitting the model parameters (layer thicknesses and volume fractions of the amorphous silicon component in the layers) by linear regression. The depth dependence of the damage was determined by both methods. It was revealed that SE can be used to investigate the radiation damage of semiconductors together with appropriate optical model construction which can be supported or independently checked by the channeling method. However, in case of low level damage (consisting mainly of isolated point defects) ellipsometry can give false results, overestimating the damage using inappropriate dielectric functions. In that case checking by other methods like channeling is desirable.
2009 8th International Conference on Reliability, Maintainability and Safety, 2009
ABSTRACT De-noising and extraction of the weak signature are crucial to fault diagnostics in whic... more ABSTRACT De-noising and extraction of the weak signature are crucial to fault diagnostics in which case features are often very weak and masked by noise. The wavelet transform has been widely used in signal de-noising due to its extraordinary time-frequency representation capability. In this paper, wavelet decomposition-based de-noising method is employed for fault feature extraction of hydraulic pump. The experiment result reveals that the wavelet decomposition de-noising method can achieve satisfactory results on weak signal detection of hydraulic pump.