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31.
Amanda M. Figueroa‐Navedo Nataly J. Galn‐Freyle Leonardo C. Pacheco‐Londoo Samuel P. Hernndez‐Rivera 《Journal of Chemometrics》2015,29(6):329-337
Infrared emissions (IREs) of samples of pentaerythritol tetranitrate (PETN) deposited as contamination residues on various substrates were measured to generate models for the detection and discrimination of the important nitrate ester from the emissions of the substrates. Mid‐infrared emissions were generated by heating the samples remotely using laser‐induced thermal emission (LITE). Chemometrics multivariate analysis techniques such as principal component analysis (PCA), soft independent modeling by class analogy (SIMCA), partial least squares‐discriminant analysis (PLS‐DA), support vector machines (SVMs), and neural network (NN) were employed to generate the models for the classification and discrimination of PETN IREs from substrate thermal emissions. PCA exhibited less variability for the LITE spectra of PETN/substrates. SIMCA was able to predict only 44.7% of all samples, while SVM proved to be the most effective statistical analysis routine, with a discrimination performance of 95%. PLS‐DA and NN achieved prediction accuracies of 94% and 88%, respectively. High sensitivity and specificity values were achieved for five of the seven substrates investigated. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Summary A new dinitrogen complex of formula Na2[Ru(PDTA)(N2)] · 2H2O has been synthesized in aqueous solution from [Ru(HPDTA) (H2O)] · H2O and NaN3. The complex has been characterized by chemical analysis, infrared and electronic spectra, and magnetic measurements. The thermal decomposition process has been studied using DTA and TG techniques. The evolution of gases was followed by gas chromatography. 相似文献
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Ivan I. Stoikov Nataly A. Fitseva Igor S. Antipin Alexander I. Konovalov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Bghly selective biological transport of amino acids is usually mediated by carrier proteins. The application of such membrane systems for the analysis and separation of amino acids has long studied. This work is devoted to the transport of zwitterionic form of aromatic a-amino acids such as d,l-Phe, d,l-DOPA, d,l-His, d,l-Tyr, d,l-Trp, via supported liquid membrane (SLM). The lipophilic α-aminophosphonates (I). R1 amyl or 2-ethylhexyl; R2, R2-(CH2)4-(CH2)5-CH3 & (CH3), C4 H(CH9) & H; H & H; have been used as carrier in the membrane systems composed of a porous polymeric support (Millipore Type FA) impregnated with 10?1 M carrier in o-nitrophenyl n-octyl ether (amino acid concentration in source phase is 10?3 M). The cell for membrane extractions is presented on Fig I. 相似文献
36.
D. C. Puerta A. M. G. Figueiredo R. Semmler R. Jaćimović 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(2):637-644
This study presents the results obtained in the application of the k 0-standardization method at the Neutron Activation Analysis Laboratory at IPEN (LAN-IPEN), for biological sample analysis, by using the k0_IAEA software, provided by the International Atomic Energy Agency (IAEA). The thermal to epithermal flux ratio f and the shape factor α of the epithermal flux distribution of the IEA-R1 nuclear reactor of IPEN were determined for the pneumatic irradiation facility and one selected irradiation position, for short and long irradiations, respectively. To obtain these factors, the “bare triple-monitor” method with 197Au–96Zr–94Zr was used. To evaluate the accuracy of the results, bias (%) and E n-number test were applied to the results obtained in the analysis of the biological reference materials NIST SRM 1547 peach leaves, INCT-MPH-2 mixed polish herbs and NIST SRM 1573a tomato leaves. Bias (%), for most elements, ranged from 0 to 30 %, in relation to certified values. E n-number values showed that, with few exceptions (Na in NIST SRM 1547 and NIST SRM 1573a, and Al, Cr, Sc and Zn in INCT-MPH-2), the results were within a 95 % CI. These results pointed to the possibility of using the k 0-INAA method with the k0_IAEA software for analysis of biological samples at LAN-IPEN. 相似文献
37.
Maximiliano Díaz Nataly Silva Nicolás Yutronic Eduardo Peña Boris Chornik Paul Jara 《Journal of inclusion phenomena and macrocyclic chemistry》2014,80(1-2):133-138
In this work, we report the nanodecoration of microcrystals of inclusion compound (IC) of γ-cyclodextrin (γ-CD) that contain octanethiol, decanethiol and dodecanethiol. Crystals of these ICs provide a suitable environment for nucleation, growth and immobilization of gold nanoparticles that were obtained by the magnetron sputtering technique. The use of γ-CD IC substrates with a specific surface morphology (i.e., the functional group of the guest molecule faces outward preferentially from a crystal plane) is an efficient method for the preparation of AuNPs with low size dispersion, which is due to the high affinity between the functional group of the surfactant alkylthiol guest with the metal nanoparticles. 相似文献
38.
While a perfect hcp (0 0 0 1) surface has threefold symmetry, the diffraction patterns commonly obtained are sixfold symmetric. This apparent change in symmetry occurs because on a stepped surface, the atomic layers on adjacent terraces are rotated by 180°. Here we use a low-energy electron microscope to acquire the threefold diffraction pattern from a single hcp Ru terrace and measure the intensity vs. energy curves for several diffracted beams. By means of multiple scattering calculations fitted to the experimental data with a Pendry R-factor of 0.077, we find that the surface is contracted by 3.5(±0.9)% at 456 K. 相似文献
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A new dinitrogen complex of formula Na2[Fe(PDTA) (N2] (H2O)2 has been synthesized in aqueous solution from [Fe(H-PDTA) (H2O)], 3/2H2O and NaN3. The complex has been characterized by chemical analysis, IR and electronic spectra, and magnetic measurements. The thermal decomposition process has been studied by using DTA and TG techniques. The evolution of gases was followed by Gas Chromatography. 相似文献