Model-driven terahertz image reconstruction method for debonding defects in thermal barrier coatings.

A terahertz imaging system is considered to be an effective method to study the thermal barrier coating defects in gas turbine engines. However, due to the influence of the system hardware and terahertz wavelength, the imaging system has slow acquisition efficiency, low image resolution, and serious edge blur, which cannot meet the demand for defect detection. To overcome the above defects, a model-driven terahertz image reconstruction method is proposed, which uses simulation data to build datasets, reduces the dependence on experimental data, and has a good reconstruction effect on experimental images.

Frequency Optimization for Enhancement of Surface Defect Classification Using the Eddy Current Technique.

Eddy current testing is quite a popular non-contact and cost-effective method for nondestructive evaluation of product quality and structural integrity. Excitation frequency is one of the key performance factors for defect characterization. In the literature, there are many interesting papers dealing with wide spectral content and optimal frequency in terms of detection sensitivity.

[Identification and classification of textiles based on terahertz time domain spectroscopy].

A method to discriminate textiles was proposed based on terahertz time-domain spectroscopy (THz-TDS) and clustering analysis, and some typical cotton textiles were investigated to prove its feasibility. Their time domain waveforms were measured using THz-TDS system and then their absorption spectra were obtained. Principal component analysis (PCA) was applied to extract features of the data, and then Mahalanobis distance discriminant method was employed to classify these materials.

[Terahertz time-domain spectroscopy of L-ascorbic acid].

The present paper reports the theoretical and experimental vibrational frequencies of L-ascorbic acid in the frequency range from 0.2 to 2.4 THz respectively.

[Terahertz spectroscopic investigation of imidacloprid].

Terahertz radiation generated by ultra short laser pulses has a broad band width in the far-infrared range. Terahertz wave interacting with materials is a new research field. In this paper, we performed measurement of absorption coefficient and refractive index of imidacloprid in the frequency range 0.