scholarly journals Using a Matlab Implemented Algorithm for UV-vis spectral Resolution for pka Determination and Multicomponent Analysis

2009 ◽  
Vol 4 ◽  
pp. ACI.S3499 ◽  
Author(s):  
Yotam Gonen ◽  
Giora Rytwo
Keyword(s):  
Spectral Resolution ◽  
Computer Code ◽  
Measured Spectrum ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Multicomponent Analysis ◽  
Value Estimation ◽  
Pka Determination ◽  
Uv Visible ◽  
The Individual

A Matlab implemented computer code for spectral resolution is presented. The code enables the user to resolve the UV-visible absorption spectrum of a mixture of up to 3 previously known components, to the individual components, thus, evaluating their quantities. The resolving procedure is based on searching the combination of the components which yields the spectrum which is the most similar (minimal RMSE) to the measured spectrum of the mixture. Examples of using the software for pKa value estimation and multicomponent analysis are presented and other implementations are suggested.

Authentication and Analysis of Olive Oil Based on Stimulated Brillouin Scattering and UV-Visible Absorption Spectrum

2018 ◽  
Vol 45 (9) ◽  
pp. 0911016
Author(s):  
曹晨鹏 Cao Chenpeng ◽  
郝仕国 Hao Shiguo ◽  
罗宁宁 Luo Ningning ◽  
史久林 Shi Jiulin ◽  
何兴道 He Xingdao
Keyword(s):  
Absorption Spectrum ◽  
Olive Oil ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Uv Visible ◽  
Stimulated Brillouin

scholarly journals Effect of Cu, Cr, S Doped TiO2 for Transparent Plastic Bar Reinforced Concrete

2020 ◽  
Vol 10 (20) ◽  
pp. 7334
Author(s):  
Seung-Hoon Seo ◽  
Byoung-Il Kim
Keyword(s):  
Absorption Spectrum ◽  
Reinforced Concrete ◽  
Visible Light ◽  
High Performance Concrete ◽  
Test Method ◽  
Visible Absorption Spectrum ◽  
Nox Removal ◽  
Transparent Plastic ◽  
Visible Absorption ◽  
Uv Visible

In this study, after firing and powdering Cu, Cr, and S with NP-400 TiO2, an NOx removal rate test was performed according to the ISO test method to analyze the photocatalytic reactivity in visible light. The distribution of the photocatalyst and visible light reactivity on the surface of the test specimen were confirmed through SEM (Scanning electron microscope), EDS (Energy dispersive spectroscopy), XRD (X-ray diffraction), UV-visible absorption spectrum and energy band gap tests. The flowability of UHPC (Ultra high performance concrete) slightly decreased due to the increase in the photocatalyst mixing rate, but both J-Ring and L-Box test results showed that there is no problem when concrete is placed. As a result of SEM and EDS tests, good microstructure and peak values were confirmed in the test specimens doped with Cu, and as a result of the XRD test, anatase and rutile peaks were confirmed in the Cu, Cr, and S specimens. In the UV-visible absorption spectrum analysis, it was confirmed that only the specimen doped with Cu maintains a high absorption power of 0.8 up to 700 nm, and the inherent band gaps are reduced to 2.9 eV, thereby increasing the possibility of reaction in visible light. Finally, as a result of the NOx removal test by the ISO test method, about 15.8% was removed for 5 h in the specimen doped with Cu, and the removal efficiency is estimated to be possible up to about 25% when applied with the TPBRC (transparent plastic bar reinforced concrete).

scholarly journals Can ozone be used to calibrate aerosol photoacoustic spectrometers?

2018 ◽  
Vol 11 (12) ◽  
pp. 6419-6427 ◽  
Author(s):  
D. Al Fischer ◽  
Geoffrey D. Smith
Keyword(s):  
Cross Section ◽  
Atmospheric Aerosols ◽  
Excitation Wavelength ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Absorption Of Light ◽  
Field Campaigns ◽  
Uv Visible ◽  
532 Nm ◽  
Efficient Transfer

Abstract. Photoacoustic spectroscopy (PAS) has become a popular technique for measuring absorption of light by atmospheric aerosols in both the laboratory and field campaigns. It has low detection limits, measures suspended aerosols, and is insensitive to scattering. But PAS requires rigorous calibration to be applied quantitatively. Often, a PAS instrument is either filled with a gas of known concentration and absorption cross section, such that the absorption in the cell can be calculated from the product of the two, or the absorption is measured independently with a technique such as cavity ring-down spectroscopy. Then, the PAS signal can be regressed upon the known absorption to determine a calibration slope that reflects the sensitivity constant of the cell and microphone. Ozone has been used for calibrating PAS instruments due to its well-known UV–visible absorption spectrum and the ease with which it can be generated. However, it is known to photodissociate up to approximately 1120 nm via the O3 + hν(>1.1eV)→O2(3Σg-) + O(3P) pathway, which is likely to lead to inaccuracies in aerosol measurements. Two recent studies have investigated the use of O3 for PAS calibration but have reached seemingly contradictory conclusions with one finding that it results in a sensitivity that is a factor of 2 low and the other concluding that it is accurate. The present work is meant to add to this discussion by exploring the extent to which O3 photodissociates in the PAS cell and the role that the identity of the bath gas plays in determining the PAS sensitivity. We find a 5 % loss in PAS signal attributable to photodissociation at 532 nm in N2 but no loss in a 5 % mixture of O2 in N2. Furthermore, we discovered a dramatic increase of more than a factor of 2 in the PAS sensitivity as we increased the O2 fraction in the bath gas, which reached an asymptote near 100 % O2 that nearly matched the sensitivity measured with both NO2 and nigrosin particles. We interpret this dependence with a kinetic model that suggests the reason for the observed results is a more efficient transfer of energy from excited O3 to O2 than to N2 by a factor of 22–55 depending on excitation wavelength. Notably, the two prior studies on this topic used different bath gas compositions, and although the results presented here do not fully resolve the differences in their results, they may at least partially explain them.

The UV-visible absorption spectrum of methylglyoxal

1991 ◽  
Vol 62 (2) ◽  
pp. 163-171 ◽  
Author(s):  
R. Meller ◽  
W. Raber ◽  
J.N. Crowley ◽  
M.E. Jenkin ◽  
G.K. Moortgat
Keyword(s):  
Absorption Spectrum ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Uv Visible

scholarly journals A UV-visible absorption spectrum denoising method based on EEMD and an improved universal threshold filter

RSC Advances ◽  
2018 ◽  
Vol 8 (16) ◽  
pp. 8558-8568 ◽  
Author(s):  
Jingwei Li ◽  
Yifei Tong ◽  
Li Guan ◽  
Shaofeng Wu ◽  
Dongbo Li
Keyword(s):  
Water Quality ◽  
Absorption Spectrum ◽  
Quality Parameters ◽  
Visible Absorption Spectrum ◽  
Visible Spectroscopy ◽  
Visible Absorption ◽  
Denoising Method ◽  
Measured Absorption ◽  
Threshold Filter ◽  
Uv Visible

When using ultraviolet-visible spectroscopy (UV-visible spectroscopy) to detect water quality parameters, the measured absorption spectrum signal often contains a lot of interference information.

scholarly journals UV-visible absorption spectrum of FAD and its reduced forms embedded in a cryptochrome protein

2020 ◽  
Vol 22 (22) ◽  
pp. 12447-12455 ◽  
Author(s):  
Karno Schwinn ◽  
Nicolas Ferré ◽  
Miquel Huix-Rotllant
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Visible Absorption Spectrum ◽  
Visible Absorption ◽  
Uv Visible ◽  
Reduced Forms

Simulation of UV-vis absorption spectra of cryptochromes and flavoproteins requires an explicit account of vibrations of the flavin chromophore embedded in protein.

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