absorption spectroscopy Articles

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Measurement of a Doubly Substituted Methane Isotopologue, 13CH3D

by Aerodyne Research, Inc.  (Oct. 14, 2014)

ABSTRACT: Methane is an important energy resource and significant long-lived greenhouse gas. Carbon and hydrogen isotope ratios have been used to better constrain the sources of methane but interpretations based on these two parameters alone can often be inconclusive. The precise measurement of a doubly substituted methane isotopologue, 13CH3D, is ...

Spectroscopic analysis of boron porphyrin complexes

by Inderscience Publishers  (Apr. 21, 2014)

Spectroscopic analyses of diboron porphyrin complexes have been performed using femtosecond transient absorption spectroscopy, fluorescence spectroscopy measurements, IR and Raman spectroscopy as well as DFT and TDDFT calculations. Transient absorption spectroscopy was used to study the dynamics of the transient species by exciting the molecule ...

Beginners Guide to Spectroscopy - Transmission

by Specac Limited  (Feb. 28, 2014)

This is the first part of our introduction to Spectroscopy, more can be found on our blog (http://specac.blogspot.co.uk). Introduction Transmission spectroscopy is the oldest and simplest technique for analysing samples in infrared. This ...

PyTrA: ultra–fast transient absorption data analysis software

by Inderscience Publishers  (Apr. 21, 2014)

Ultra–fast transient absorption spectra are inherently complex data sets to process. PyTrA is a new software system that has been written to bring together many of the most well–known techniques of analysis into one easy–to–use package. Figure of publishable quality can be generated, and advanced 3D graphs can be used to view the transient data in ...

Characterizing natural dissolved organic matter in a freshly submerged catchment (Three Gorges Dam, China) using UV absorption, fluorescence spectroscopy and PARAFAC

by IWA Publishing  (Feb. 1, 2012)

This study applied parallel factor analysis (PARAFAC) to fluorescence excitation–emission matrices (EEMs) of natural water samples in a freshly submerged catchment in the upper reach of Three Gorges Dam (China). Two fluorescent natural dissolved organic matter (NDOM) components (humic/fulvic-like) were uncovered and were positively correlated with ...

Real Time Measurments of Acetylene in Ethylene Manufacturing Process

by Ametek Process Instruments - THERMOX  (Nov. 14, 2014)

Keywords Tunable Diode Laser, Wavelength Modulation Spectroscopy, Analyzer, Acetylene, Ethylene, Acetylene Converter Abstract The analyzer, based on near infrared Tunable Diode Laser Absorption Spectroscopy (TDLAS), was developed for the measurement of acetylene in process streams. Measurements of acetylene were made as under laboratory ...

Wastewater salinity assessment using near infrared spectroscopy

by IWA Publishing  (Aug. 29, 2013)

The visible and near infrared spectroscopy is a fast and inexpensive non-destructive technique for the prediction of concentrations of salts in wastewater. Conventional chemical methods are usually used, which are very accurate, take more time and require special techniques for sampling, storing and pretreatment of wastewater. In this work we ...

Identification of forensic fabrics using a portable Raman spectrometer

by B&W Tek, Inc  (Oct. 28, 2014)

At a crime scene, a police officer collects a fiber sample that may prove to be invaluable evidence in identifying a criminal or exonerating an innocent person. While FTIR has been used for analysis in the past, the strong absorption of the fabric or the glass slide where it is mounted makes the spectrum very hard to interpret. In recent years, ...

FTIR Spectroscopy

by CIC Photonics, Inc.  (Aug. 9, 2011)

Fourier Transform Infrared (FTIR) Spectroscopy bases its functionality on the principle that almost all molecules absorb infrared light. Only the monatomic (He, Ne, Ar, etc) and homopolar diatomic (H2, N2, O2, etc) molecules do not absorb infrared light. Molecules only absorb infrared light at those frequencies where the infrared light affects the ...

Application of surface complexation models to anion adsorption by natural materials

by John Wiley & Sons, Ltd.  (Mar. 11, 2014)

Various chemical models of ion adsorption will be presented and discussed. Chemical models, such as surface complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model will be described. Characteristics common to all ...

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