New discovery in crystallography: correlation of terahertz time-domain spectra with crystal structures and photoluminescence properties of mononuclear/binuclear diimine–Cu(i)-phosphine complexes

CrystEngComm ◽  
2019 ◽  
Vol 21 (29) ◽  
pp. 4275-4288 ◽  
Author(s):  
Ning Zhu ◽  
Guo Wang ◽  
Sen Lin ◽  
Zhong-Feng Li ◽  
Xiu-Lan Xin ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Crystal Structures ◽  
Time Domain ◽  
Photoluminescence Properties ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Phosphine Complexes ◽  
Photoluminescence Quantum Yield ◽  
New Discovery

A method was provided for qualitatively determining the photoluminescence quantum yield of diimine–Cu(i) complex by the waveform of terahertz time-domain spectroscopy.

scholarly journals Multivariate Analysis for the Classification of Chocolate According to its Percentage of Cocoa by Using Terahertz Time-Domain Spectroscopy (THz-TDS)

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 109
Author(s):  
Jimy Oblitas ◽  
Jorge Ruiz
Keyword(s):  
Machine Learning ◽  
Time Domain ◽  
Electromagnetic Pulse ◽  
Machine Learning Algorithms ◽  
Classification Models ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Svm Algorithm ◽  
Classification Of Images

Terahertz time-domain spectroscopy is a useful technique for determining some physical characteristics of materials, and is based on selective frequency absorption of a broad-spectrum electromagnetic pulse. In order to investigate the potential of this technology to classify cocoa percentages in chocolates, the terahertz spectra (0.5–10 THz) of five chocolate samples (50%, 60%, 70%, 80% and 90% of cocoa) were examined. The acquired data matrices were analyzed with the MATLAB 2019b application, from which the dielectric function was obtained along with the absorbance curves, and were classified by using 24 mathematical classification models, achieving differentiations of around 93% obtained by the Gaussian SVM algorithm model with a kernel scale of 0.35 and a one-against-one multiclass method. It was concluded that the combined processing and classification of images obtained from the terahertz time-domain spectroscopy and the use of machine learning algorithms can be used to successfully classify chocolates with different percentages of cocoa.

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