Выбор переменных в ультрафиолетовом, видимом и ближнем инфракрасном диапазонах для калибровки смеси растительных масел по спектрам оптической плотности

The aim of the work was a multivariate calibration of the concentration of unrefined sunflower oil, considered as adulteration, in a mixture with flaxseed oil. The relevance of the study is due to the need to develop a simple and effective method for detecting the falsification of flaxseed oil which is superior in the content of essential polyunsaturated fatty acids to olive oil. A few works only are devoted to identifying adulteration of flaxseed oil, unlike olive oil.Multivariate calibration carried out using a model based on the principal component analysis, cluster analysis and projection to latent structures of absorbance spectra in UV, visible and near IR ranges. Calibration uses three methods for spectral variables selection: the successive projections algorithm, the method of searching combination moving window, and method for ranking variables by correlation coefficient.The application of the successive projections algorithm, ranking variables by correlation coefficient and searching combination moving window makes it possible to reduce the value of the root mean square error of prediction from 0.63 % for wideband projection to latent structures to 0.46 %, 0.50 %, and 0.03 %, respectively.The developed method of multivariate calibration by projection to latent structures of absorbance spectra in UV, visible and near IR ranges using the spectral variables selection by searching combination moving window is a simple and effective method of detecting adulteration of flaxseed oil.Целью работы являлась многопараметрическая калибровка концентрации нерафинированного подсолнечного масла, рассматриваемого в качестве фальсификата льняного масла. Актуальность исследования обусловлена необходимостью разработки простого и эффективного метода обнаружения фальсификации льняного масла, превосходящего по содержанию незаменимых полиненасыщенных жирных кислот оливковое масло, выявлению подделок которого в отличие от льняного посвящено большое количество работ.Многопараметрическая калибровка проводилась с помощью модели, основанной на методе главных компонент, кластерном анализе и проекции на латентные структуры спектров оптической плотности в УФ-, видимом и ближнем ИК диапазонах с применением трех методов выбора спектральных переменных: метода последовательного проецирования, метода поиска комбинации сдвигающихся окон и метода ранжирования переменных по коэффициенту корреляции.Показано, что применение методов последовательного проецирования, ранжирования переменных по коэффициенту корреляции и поиска комбинации сдвигающихся спектральных окон позволяет уменьшить величину среднеквадратичного отклонения калибровки с 0,63 % для широкополосной проекции на латентные структуры до 0,46 %, 0,50 % и 0,03 %, соответственно.Разработанный метод многопараметрической калибровки с помощью проекции на латентные структуры спектров оптической плотности в УФ-, видимом и ближнем ИК диапазонах с применением выбора спектральных переменных путём поиска комбинации сдвигающихся окон является простым и эффективным средством обнаружения фальсификации льняного масла

Nanostructured silver substrates with stable and universal sers properties: Application to organic molecules and semiconductor nanoparticles

Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60-80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time. © 2009 The Author(s)

Nanostructured Silver Substrates With Stable and Universal SERS Properties: Application to Organic Molecules and Semiconductor Nanoparticles

Nanostructured silver films have been prepared by thermal deposition on silicon, and their properties as SERS substrates investigated. The optimal conditions of the post-growth annealing of the substrates were established. Atomic force microscopy study revealed that the silver films with relatively dense and homogeneous arrays of 60–80-nm high pyramidal nanoislands are the most efficient for SERS of both organic dye and inorganic nanoparticles analytes. The noticeable enhancement of the Raman signal from colloidal nanoparticles with the help of silver island films is reported for the first time

Выбор переменных в ультрафиолетовом, видимом и ближнем инфракрасном диапазонах для калибровки смеси растительных масел по спектрам оптической плотности

The aim of the work was a multivariate calibration of the concentration of unrefined sunflower oil, considered as adulteration, in a mixture with flaxseed oil. The relevance of the study is due to the need to develop a simple and effective method for detecting the falsification of flaxseed oil which is superior in the content of essential polyunsaturated fatty acids to olive oil. A few works only are devoted to identifying adulteration of flaxseed oil, unlike olive oil. Multivariate calibration carried out using a model based on the principal component analysis, cluster analysis and projection to latent structures of absorbance spectra in UV, visible and near IR ranges. Calibration uses three methods for spectral variables selection: the successive projections algorithm, the method of searching combination moving window, and method for ranking variables by correlation coefficient. The application of the successive projections algorithm, ranking variables by correlation coefficient and searching combination moving window makes it possible to reduce the value of the root mean square error of prediction from 0.63 % for wideband projection to latent structures to 0.46 %, 0.50 %, and 0.03 %, respectively. The developed method of multivariate calibration by projection to latent structures of absorbance spectra in UV, visible and near IR ranges using the spectral variables selection by searching combination moving window is a simple and effective method of detecting adulteration of flaxseed oil

Low-energy high-dose implantation of nitrogen into high-speed steel

Translated from Russian (Fiz. Khim. Obrab. Mater. 1997 (6) 33-36)Available from British Library Document Supply Centre-DSC:9023.190(9620)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo