The pulsed infrared thermal image sequence characteristics of the coating structure was analyzed, and the temperature
change process of any pixel including status and time parameters was considered as discrete Markov process. A
combination of Markov and principal component analysis (PCA) algorithm were proposed to process the pulsed infrared
image sequence. First, using the Markov method to achieve the image sequence reconstruction, then using PCA method
to achieve the original complex data dimensionality reduction to remove the noise and redundancy, and extract the main
components reflecting the main features of the data. Results show that the processed images have higher SNR. Results
show that the processed images have much higher SNR than that of the original thermal image with the best contrast.
This paper provides an investigation of the ablation behavior of single crystal 4H-SiC and 6H-SiC wafer to improve the
manufacturability and high-temperature performance of SiC using laser applications. 266nm pulsed laser
micromachining of SiC was investigated. The purpose is to establish suitable laser parametric regime for the fabrication
of high accuracy, high spatial resolution and thin diaphragms for high-temperature MEMS pressure sensor applications.
Etch rate, ablation threshold and quality of micromachined features were evaluated. The governing ablation mechanisms,
such as thermal vaporization, phase explosion, and photomechanical fragmentation, were correlated with the effects of
pulse energy. The ablation threshold is obtained with ultraviolet pulsed laser ablation. The results suggested ultraviolet
pulsed laser’s potential for rapid manufacturing. Excellent quality of machined features with little collateral thermal
damage was obtained in the lower pulse energy range. The leading material removal mechanisms under these conditions
were discussed.
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