Two-Dimensional Correlation Analysis of Visible/Near-Infrared Spectral Intensity Variations of Chicken Breasts with Various Chilled and Frozen Storages

2004 ◽  
Vol 52 (3) ◽  
pp. 505-510 ◽  
Author(s):  
Yongliang Liu ◽  
Franklin E. Barton ◽  
Brenda G. Lyon ◽  
William R. Windham ◽  
Clyde E. Lyon
Keyword(s):  
Correlation Analysis ◽  
Near Infrared ◽  
Spectral Intensity ◽  
Two Dimensional ◽  
Infrared Spectral

Study of the Infrared Spectral Features of an Epoxy Curing Mechanism

2008 ◽  
Vol 62 (10) ◽  
pp. 1129-1136 ◽  
Author(s):  
Liang Li ◽  
Qili Wu ◽  
Shanjun Li ◽  
Peiyi Wu
Keyword(s):  
Correlation Analysis ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Diglycidyl Ether ◽  
Hydroxyl Groups ◽  
Spectral Correlation ◽  
Derivative Analysis ◽  
Curing Mechanism ◽  
Infrared Spectral ◽  
Epoxy Groups

In this work, the isothermal curing process of diglycidyl ether of bisphenol A(DGEBA) cured with 4,4′-diaminodiphenylmethane (DDM) was monitored in situ by mid-infrared (MIR) and near-infrared (NIR) spectroscopy. With the help of generalized two-dimensional (2D) correlation analysis, the results obtained showed that, during curing, the change of amine and epoxy groups was simultaneous, taking place prior to the change of hydroxyl groups, followed by the change of CH2/CH groups, resulting from the ring-opening reaction of epoxy groups. In addition, 2D MIR×NIR hetero-spectral correlation analysis and second-derivative analysis were also employed, by means of which direct evidence of the curing mechanism could be obtained and obscure NIR band assignments in the overlapped CH combination region could be made.

The Effect of Chain Length on Mid-Infrared and Near-Infrared Spectra of Aliphatic 1-Alcohols

2017 ◽  
Vol 72 (2) ◽  
pp. 288-296 ◽  
Author(s):  
Michał Kwaśniewicz ◽  
Mirosław A. Czarnecki
Keyword(s):  
Correlation Analysis ◽  
Chain Length ◽  
Near Infrared ◽  
Hydrophobic Interactions ◽  
Principal Component ◽  
Butyl Alcohol ◽  
Two Dimensional ◽  
Data Set ◽  
Mid Infrared ◽  
Spectral Changes

Effect of the chain length on mid-infrared (MIR) and near-infrared (NIR) spectra of aliphatic 1-alcohols from methanol to 1-decanol was examined in detail. Of particular interest were the spectra-structure correlations in the NIR region and the correlation between MIR and NIR spectra of 1-alcohols. An application of two-dimensional correlation analysis (2D-COS) and chemometric methods provided comprehensive information on spectral changes in the data set. Principal component analysis (PCA) and cluster analysis evidenced that the spectra of methanol, ethanol, and 1-propanol are noticeably different from the spectra of higher 1-alcohols. The similarity between the spectra increases with an increase in the chain length. Hence, the most similar are the spectra of 1-nonanol and 1-decanol. Two-dimensional hetero-correlation analysis is very helpful for identification of the origin of bands and may guide selection of the best spectral ranges for the chemometric analysis. As shown, normalization of the spectra pronounces the intensity changes in various spectral regions and provides information not accessible from the raw data. The spectra of alcohols cannot be represented as a sum of the CH3, CH2, and OH group spectra since the OH group is involved in the hydrogen bonding. As a result, the spectral changes of this group are nonlinear and its spectral profile cannot be properly resolved. Finally, this work provides a lot of evidence that the degree of self-association of 1-alcohols decreases with the increase in chain length because of the growing meaning of the hydrophobic interactions. For butyl alcohol and higher 1-alcohols the hydrophobic interactions are more important than the OH OH interactions. Therefore, methanol, ethanol, and 1-propanol have unlimited miscibility with water, whereas 1-butanol and higher 1-alcohols have limited miscibility with water.

scholarly journals Classification by Photoelectric Measurements of Molecular Bands: Current Status and Future Prospects

1979 ◽  
Vol 47 ◽  
pp. 347-373
Author(s):  
Robert F. Wing
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Current Status ◽  
Two Dimensional ◽  
Future Prospects ◽  
Late Type ◽  
Classification Technique ◽  
Cool Stars ◽  
Infrared Spectral ◽  
Photoelectric Measurements

AbstractAs a classification technique, photoelectric narrow-band photometry is especially effective in the case of late-type spectra, in which molecular bands furnish the most sensitive criteria. Measurements of molecular bands with bandpasses of about 50 Å can be made very efficiently, and for normal stars they can be calibrated in terms of temperature and luminosity. In the case of normal late-type giants and supergiants, two-dimensional classifications can be obtained from measurements of TiO and CN; for very cool giants and for dwarfs it is useful siso to measure VO and CaH, respectively. All these molecules have bands in the red and near-infrared spectral regions, where cool stars are relatively bright and where photometric accuracy is highest.

Wavelength-Selective Solar Thermal Absorber With Two-Dimensional Nickel Gratings

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Bong Jae Lee ◽  
Yu-Bin Chen ◽  
Sunwoo Han ◽  
Feng-Cheng Chiu ◽  
Hyun Jin Lee
Keyword(s):  
Solar Radiation ◽  
Near Infrared ◽  
Broad Band ◽  
Sio2 Film ◽  
Solar Thermal ◽  
Local Magnetic Field ◽  
Absorption Enhancement ◽  
Two Dimensional ◽  
Nickel Substrate ◽  
Infrared Spectral

The direct utilization of solar radiation has been considered a promising energy source because of its abundance, sustainability, and cleanness. The conversion of solar radiation into usable heat largely depends on the absorption characteristics of a solar thermal collector. In the present study, we conducted design analysis of a wavelength-selective absorber composed of a two-dimensional Nickel grating, a thin SiO2 film, and a Nickel substrate. Dimensions of the two-dimensional grating were determined with the Taguchi method, which optimized the spectral absorptance for both polarizations. The spectral absorptance demonstrated a broad-band plateau within the visible and the near-infrared spectral region, but it was significantly suppressed at longer wavelengths. Moreover, the absorptance plateau was nearly insensitive to the incident orientation of solar radiation. Physical mechanisms of the absorption enhancement were elucidated with the local magnetic field distribution.

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