scholarly journals Spectroscopic Studies of Er3+-Yb3+ Codoped Multicomposition Tellurite Oxide Glass

2014 ◽  
Vol 895 ◽  
pp. 323-333 ◽  
Author(s):  
Sharudin Omar Baki ◽  
L.S. Tan ◽  
C.S. Kan ◽  
Halimah Mohamed Kamari ◽  
A.S.M. Noor ◽  
...  
Keyword(s):  
Room Temperature ◽  
Near Infrared ◽  
Transition Probabilities ◽  
Branching Ratios ◽  
Spectroscopic Studies ◽  
Oxide Glass ◽  
Near Infrared Spectra ◽  
Intensity Parameters ◽  
Measured Absorption

Multicomposition of Er3+-Yb3+codoped tellurite oxide, TeO2-ZnO-PbO-TiO2-Na2O glass has been investigated. Detailed spectroscopic study of the Judd-Ofelt analysis has been performed from the measured absorption spectrum in order to obtain the intensity parameters Ωt(t=2, 4, 6). The calculated Ωtvalues were then utilized in the determination of transition probabilities, radiative lifetimes and branching ratios of the Er3+transitions between theJ(upper)-J(lower) manifolds. Both visible upconversion and near-infrared spectra were characterized under the 980 nm laser diode excitation at room temperature.

Determination of Sulfamethoxydiazine in Pig Feed Based on Transmittance near Infrared Spectra

2012 ◽  
Vol 20 (3) ◽  
pp. 397-406
Author(s):  
Qingbo Fu ◽  
Xinping He ◽  
Hui Suo ◽  
Jinming Wang ◽  
Chun Zhao
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Near Infrared Spectra ◽  
Pig Feed

Near Infrared Spectroscopic Examination of Charred Pine Wood, Bark, Cellulose and Lignin: Implications for the Quantitative Determination of Charcoal in Soils

2007 ◽  
Vol 15 (5) ◽  
pp. 307-315 ◽  
Author(s):  
James B. Reeves ◽  
Gregory W. McCarty ◽  
David W. Rutherford ◽  
Robert L. Wershaw
Keyword(s):  
Carboxylic Acids ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Direct Determination ◽  
Pine Wood ◽  
Oh Groups ◽  
Spectral Changes ◽  
Near Infrared Spectra ◽  
Material Temperature

The objective of this research was to investigate the effect of charring on near infrared spectra of materials likely to be present in forest fires in order to determine the feasibility of determining charred carbon in soils. Four materials (cellulose, lignin, pine bark and pine wood) and char from these materials created by charring for various durations (1 to 168 h) and at various temperatures (200 to 450°C) were studied. Near infrared spectra and measures of acidity (total acids, carboxylic acids, lactones and phenols as determined by titration) were available for 56 different samples (Not all samples charred at all temperatures/durations). Results showed spectral changes that varied with the material, temperature and duration of charring. Examination of spectra and correlation plots indicated that changes in the constituents of the materials in question, such as loss of OH groups in carbohydrates, rather than direct determination of typical products produced by charring, such as carboxylic acids, lactones and phenols, were the basis for the spectral changes. Finally, while the spectral changes resulting from charring appeared to be relatively unique to each material, PLS calibrations for total acids, carboxylic acids, lactones and phenols were successfully created (with R2 of 0.991, 0.943, 0.931 and 0.944, respectively) indicating that there is a sufficient commonality in the changes to develop calibrations without the need for unique calibrations for each specific set of charring conditions (i.e. material, temperature and time of heating).

DWT-PLS Regression on Near-Infrared Spectra for Moisture and Volatile Determination of Coal

2013 ◽  
Vol 848 ◽  
pp. 313-316
Author(s):  
Xiao Li Yang ◽  
Fan Wang ◽  
Ji Shu Chen ◽  
Gong Zhe Ma
Keyword(s):  
Partial Least Squares Regression ◽  
Bituminous Coal ◽  
Near Infrared ◽  
Parameters Optimization ◽  
Discrete Wavelet ◽  
Pls Regression ◽  
Least Squares Regression ◽  
Satisfactory Performance ◽  
Near Infrared Spectra

We studied moisture and volatile determination in bituminous coal samples using near-infrared (NIR) spectra. This research was developted by applying partial least squares regression (PLS) and discrete wavelet transform (DWT). Firstly, NIR spectra were pre-processed by DWT for fitting and compression. Then, DWT coefficients were used to build regression model with PLS. We used NIR spectra to determination moisture and volatile determination in coal samples seperately and simultaneously. Through parameters optimization, the results show that DWT-PLS can obtain satisfactory performance for separate and simultanous determination.

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