Near-infrared spectra of water and aqueous electrolyte solutions at high pressures

1984 ◽  
Vol 13 (11) ◽  
pp. 811-823 ◽  
Author(s):  
A. Inoue ◽  
K. Kojima ◽  
Y. Taniguchi ◽  
K. Suzuki
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
High Pressures ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Aqueous Electrolyte Solutions ◽  
Near Infrared Spectra

Measurement of the Near-Infrared Spectra of H2O-SiOH-Bearing Siliceous Materials at High Pressures

1979 ◽  
Vol 33 (5) ◽  
pp. 495-499 ◽  
Author(s):  
Klaus Langer ◽  
Werner A. P. Luck ◽  
Otto Schrems
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
High Pressures ◽  
Band System ◽  
High Energy ◽  
Single Beam ◽  
Near Infrared Spectra ◽  
Diamond Anvil ◽  
Combination Bands ◽  
Energy Components

Techniques for measuring OH-combination bands of water and other OH-group bearing solid or liquid materials in the near-infrared (6000 to 4000 cm−1) at high pressures by means of a modified diamond anvil cell, adapted to a single beam micro-spectrometer, have been developed and applied to opals, i.e., minerals in the system SiO2-H2O containing relatively high amounts of water and SiOH. Liquid embedding, using the gasket technique and poly-fluoro-carbon oils as embedding liquids, which provide a hydrostatic pressure environment at least up to 50 kbar, is applied for solid materials. The high pressure near-infrared spectra of gel-like, spherulitic opal-AG show a strong relative decrease of the high energy components of the complex (v1 + v2)H2O-band system at around 5200 cm−1 in favor of the low energy components of this band system. This is tentatively interpreted as due to an increase of fully hydrogen bonded water at the expense of water in which only one OH-group is H-bonded. The corresponding effect in opal-AN with a glass-like continuous SiO4/2-tetrahedral network is much smaller.

Promoting Nitrogen Electroreduction to Ammonia with Bismuth Nanocrystals and Potassium Cations in Water

2020 ◽  
Author(s):  
Jaecheol Choi ◽  
Hoang-Long Du ◽  
Manjunath Chatti ◽  
Bryan H. R. Suryanto ◽  
Alexandr Simonov ◽  
...  
Keyword(s):  
Electrocatalytic Activity ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Reduction Reaction ◽  
Nitrogen Reduction ◽  
Aqueous Electrolyte Solutions

We demonstrate that bismuth exhibits no measurable electrocatalytic activity for the nitrogen reduction reaction to ammonia in aqueous electrolyte solutions, contrary to several recent reports on the highly impressive rates of Bi-catalysed electrosynthesis of NH<sub>3</sub> from N<sub>2</sub>.

Rapid Determining Contents of the Rhubarb Anthraquinones Compounds by Support Vector Machines Modeling based on Near Infrared Spectra

2020 ◽  
Vol 16 ◽  
Author(s):  
Linqi Liu ◽  
JInhua Luo ◽  
Chenxi Zhao ◽  
Bingxue Zhang ◽  
Wei Fan ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Near Infrared ◽  
Mean Squared Error ◽  
Rapid Determination ◽  
Partial Least Square ◽  
Least Square ◽  
Support Vector ◽  
Near Infrared Spectra ◽  
Aloe Emodin ◽  
Relative Differences

BACKGROUND: Measuring medicinal compounds to evaluate their quality and efficacy has been recognized as a useful approach in treatment. Rhubarb anthraquinones compounds (mainly including aloe-emodin, rhein, emodin, chrysophanol and physcion) are its main effective components as purgating drug. In the current Chinese Pharmacopoeia, the total anthraquinones content is designated as its quantitative quality and control index while the content of each compound has not been specified. METHODS: On the basis of forty rhubarb samples, the correlation models between the near infrared spectra and UPLC analysis data were constructed using support vector machine (SVM) and partial least square (PLS) methods according to Kennard and Stone algorithm for dividing the calibration/prediction datasets. Good models mean they have high correlation coefficients (R2) and low root mean squared error of prediction (RMSEP) values. RESULTS: The models constructed by SVM have much better performance than those by PLS methods. The SVM models have high R2 of 0.8951, 0.9738, 0.9849, 0.9779, 0.9411 and 0.9862 that correspond to aloe-emodin, rhein, emodin, chrysophanol, physcion and total anthraquinones contents, respectively. The corresponding RMSEPs are 0.3592, 0.4182, 0.4508, 0.7121, 0.8365 and 1.7910, respectively. 75% of the predicted results have relative differences being lower than 10%. As for rhein and total anthraquinones, all of the predicted results have relative differences being lower than 10%. CONCLUSION: The nonlinear models constructed by SVM showed good performances with predicted values close to the experimental values. This can perform the rapid determination of the main medicinal ingredients in rhubarb medicinal materials.

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