Showing posts with label Ming Li. Show all posts
Showing posts with label Ming Li. Show all posts

Thursday, December 26, 2019

Abstract-Determination of Invert Syrup Adulterated in Acacia Honey by Terahertz Spectroscopy with Different Spectral Features






BACKGROUND

Invert syrup is a common adulterant in honey falsification, thus generating risk for consumers. The most of developed methods are tedious and time‐consuming for manufactures and consumers. However, terahertz spectroscopy provides analytical information in a simple, rapid and environmentally friendly manner. Subsequently, three terahertz spectroscopic characteristics data, the absorption coefficient, the slope of the absorption coefficient spectra and the area of the absorption coefficient spectra, were employed for determination of Acacia honey adulterated with invert syrup.

RESULTS

Single linear regression (SLR) models with different terahertz spectroscopic features were adopted to predict the syrup adulterant proportion in Acacia honey, respectively. The best SLR model was used the area of the absorption coefficient, displaying an adjusted correlation coefficient of 0.985 and a root mean square error of 3.201. Meanwhile, multiple linear regression (MLR) models using successive projections algorithm for variables selection were implemented. MLR model considered the integral area of the absorption coefficient spectra as the inputs yielded the best result with less selected variables, higher Rc2 and Rp2, lower root mean square error of calibration and prediction as well as higher residual predictive deviation.

CONCLUSIONS

The results indicate terahertz spectroscopy combined with the integral area of the absorption coefficient spectra is reliable enough for invert syrup proportion quantification in Acacia honey and is also a rapid and non‐destructive determination method for other honey adulterants.
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Tuesday, October 21, 2014

Abstract-Terahertz-bandwidth photonic fractional Hilbert transformer based on a phase-shifted waveguide Bragg grating on silicon


Maurizio Burla, Ming Li, Luis Romero Cortés, Xu Wang, María Rosario Fernández-Ruiz, Lukas Chrostowski, and José Azaña  »View Author Affiliations

Optics Letters, Vol. 39, Issue 21, pp. 6241-6244 (2014)
http://dx.doi.org/10.1364/OL.39.006241
http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-39-21-6241
We propose and experimentally demonstrate the first THz bandwidth on-chip photonic fractional Hilbert transformer. The reported design uses a novel approach, based on a uniform and nonapodized single phase-shifted integrated waveguide Bragg grating on silicon, where the fractional order P can be engineered by simply varying the effective index modulation δn. Experimental results for P=1.5 show very low processing error for a broad range of pulse bandwidths between 77 GHz and 2.07 THz, corresponding to a time-bandwidth product as high as 27.
© 2014 Optical Society of America