52 research outputs found

    A Statistical Approach to Estimating Adsorption-Isotherm Parameters in Gradient-Elution Preparative Liquid Chromatography

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    Determining the adsorption isotherms is an issue of significant importance in preparative chromatography. A modern technique for estimating adsorption isotherms is to solve an inverse problem so that the simulated batch separation coincides with actual experimental results. However, due to the ill-posedness, the high non-linearity, and the uncertainty quantification of the corresponding physical model, the existing deterministic inversion methods are usually inefficient in real-world applications. To overcome these difficulties and study the uncertainties of the adsorption-isotherm parameters, in this work, based on the Bayesian sampling framework, we propose a statistical approach for estimating the adsorption isotherms in various chromatography systems. Two modified Markov chain Monte Carlo algorithms are developed for a numerical realization of our statistical approach. Numerical experiments with both synthetic and real data are conducted and described to show the efficiency of the proposed new method.Comment: 28 pages, 11 figure

    Fine-tuned silica nanohelices as platforms for chiral organization of gold nanoparticles : synthesis, characterization and chiroptical analysis

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    Nanomatériaux de silice peuvent être facilement fabriqués, façonné et fonctionnalisés comme plates-formes pour le greffage des nanoparticules pour des applications biomédicales et optiques. Ici, nous utilisons une méthodologie basée sur un modèle de préparer une collection variée de hélicoïdale nanoparticules d'or (PNB) superstructures ayant impartialité contrôlable et mesures structurelles en utilisant PNB que les blocs de construction, et les nanohelices de silice que le modèle. Le matériaux présentent synthétisé bien définir Agencement chiral de PNB suivant l'hélicité de nanohelices de silice, montrant des signaux plasmoniques de dichorism circulaire (CD). D'autres observations ont prouvé ce plasmon CD vient de l'arrangement chiral de PNB et cet effet est très taille, l'échelle et dépend du pH. Nous nous attendons à ce que cette stratégie d'assemblage va découvrir une meilleure vue sur les métamatériaux et de susciter la vue vers "bottom-up" des approches en nanosciences.Silica nanomaterials can be easily fabricated, fashioned and functionalized as platforms for grafting of nanoparticles for biomedical and optical applications. Herein, we utilize a template-based methodology to prepare a diverse collection of helical gold nanoparticle (GNPs) superstructures having controllable handedness and structural metrics by using GNPs as the building blocks, and the silica nanohelices as the template. The synthesized materials exhibit well-defined chiral arrangement of GNPs following the helicity of silica nanohelices, showing plasmonic circular dichorism (CD) signals. Further observations proved this plasmon CD comes from the chiral arrangement of GNPs and this effect is highly size, scale and pH dependent. We expect that this assembly strategy will discover a better view towards metamaterials and spark the view towards “bottom-up” approaches in nanoscience

    Nanohélices de silice de morphologie contrôlée utilisées comme plateforme pour l'organisation chirale de nanoparticules d'or : synthèse, caractérisation et analyses chiro-optiques

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    Silica nanomaterials can be easily fabricated, fashioned and functionalized as platforms for grafting of nanoparticles for biomedical and optical applications. Herein, we utilize a template-based methodology to prepare a diverse collection of helical gold nanoparticle (GNPs) superstructures having controllable handedness and structural metrics by using GNPs as the building blocks, and the silica nanohelices as the template. The synthesized materials exhibit well-defined chiral arrangement of GNPs following the helicity of silica nanohelices, showing plasmonic circular dichorism (CD) signals. Further observations proved this plasmon CD comes from the chiral arrangement of GNPs and this effect is highly size, scale and pH dependent. We expect that this assembly strategy will discover a better view towards metamaterials and spark the view towards “bottom-up” approaches in nanoscience.Nanomatériaux de silice peuvent être facilement fabriqués, façonné et fonctionnalisés comme plates-formes pour le greffage des nanoparticules pour des applications biomédicales et optiques. Ici, nous utilisons une méthodologie basée sur un modèle de préparer une collection variée de hélicoïdale nanoparticules d'or (PNB) superstructures ayant impartialité contrôlable et mesures structurelles en utilisant PNB que les blocs de construction, et les nanohelices de silice que le modèle. Le matériaux présentent synthétisé bien définir Agencement chiral de PNB suivant l'hélicité de nanohelices de silice, montrant des signaux plasmoniques de dichorism circulaire (CD). D'autres observations ont prouvé ce plasmon CD vient de l'arrangement chiral de PNB et cet effet est très taille, l'échelle et dépend du pH. Nous nous attendons à ce que cette stratégie d'assemblage va découvrir une meilleure vue sur les métamatériaux et de susciter la vue vers "bottom-up" des approches en nanosciences

    Fine-tuned silica nanohelices as platforms for chiral organization of gold nanoparticles : synthesis, characterization and chiroptical analysis

    No full text
    Nanomatériaux de silice peuvent être facilement fabriqués, façonné et fonctionnalisés comme plates-formes pour le greffage des nanoparticules pour des applications biomédicales et optiques. Ici, nous utilisons une méthodologie basée sur un modèle de préparer une collection variée de hélicoïdale nanoparticules d'or (PNB) superstructures ayant impartialité contrôlable et mesures structurelles en utilisant PNB que les blocs de construction, et les nanohelices de silice que le modèle. Le matériaux présentent synthétisé bien définir Agencement chiral de PNB suivant l'hélicité de nanohelices de silice, montrant des signaux plasmoniques de dichorism circulaire (CD). D'autres observations ont prouvé ce plasmon CD vient de l'arrangement chiral de PNB et cet effet est très taille, l'échelle et dépend du pH. Nous nous attendons à ce que cette stratégie d'assemblage va découvrir une meilleure vue sur les métamatériaux et de susciter la vue vers "bottom-up" des approches en nanosciences.Silica nanomaterials can be easily fabricated, fashioned and functionalized as platforms for grafting of nanoparticles for biomedical and optical applications. Herein, we utilize a template-based methodology to prepare a diverse collection of helical gold nanoparticle (GNPs) superstructures having controllable handedness and structural metrics by using GNPs as the building blocks, and the silica nanohelices as the template. The synthesized materials exhibit well-defined chiral arrangement of GNPs following the helicity of silica nanohelices, showing plasmonic circular dichorism (CD) signals. Further observations proved this plasmon CD comes from the chiral arrangement of GNPs and this effect is highly size, scale and pH dependent. We expect that this assembly strategy will discover a better view towards metamaterials and spark the view towards “bottom-up” approaches in nanoscience

    Comparison and Analysis of Stellar Occultation Simulation Results and SABER-Satellite-Measured Data in Near Space

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    In this study, we analyze the accuracy of the stellar occultation technique to detect the oxygen number density and temperature in near space. Based on the validation of the algorithm related to stellar occultation using a single wavelength of 762 nm, the simulation and inversion are performed using the oxygen absorption A-band, and the results are compared with SABER observations to calculate the deviation. Then, the distribution of the detection accuracy with wavelength, latitude, and altitude is analyzed. The results show that the radiant transmittance of the basic observation varies significantly with wavelength and altitude, and it is not sensitive to a change of latitude. The inversion results of each wavelength at different latitudes can be combined, and it can be seen that the 754–769 nm band is preferred for oxygen and temperature detection. Therefore, analyzing the accuracy results of the specific wavelength 757.84 nm at different latitudes, the temperature accuracy can reach 0.1 K in the stratosphere at both low and high latitudes and 0.6–34 K at middle latitudes. The temperature detection accuracy in the mesosphere at each latitude reaches about a dozen K. The deviation of the inversion results at middle latitudes is larger in the thermosphere, and at the other two latitudes, it is about a few dozen K. From the analysis of relative deviation, excluding the deviation of 95–100 km, the deviation of other altitudes is within the ideal range, and the minimum can reach 0. The accuracy of the oxygen number density increases with latitude, and the relative deviation of the middle and high latitudes is around 10–20%. Based on the above results, it is concluded that the technique of starlight occultation exhibits high accuracy for detecting atmospheric parameters in the near space region, and the results lay the technical foundation for the independent development of stellar occultation

    Comparison and Analysis of Stellar Occultation Simulation Results and SABER-Satellite-Measured Data in Near Space

    No full text
    In this study, we analyze the accuracy of the stellar occultation technique to detect the oxygen number density and temperature in near space. Based on the validation of the algorithm related to stellar occultation using a single wavelength of 762 nm, the simulation and inversion are performed using the oxygen absorption A-band, and the results are compared with SABER observations to calculate the deviation. Then, the distribution of the detection accuracy with wavelength, latitude, and altitude is analyzed. The results show that the radiant transmittance of the basic observation varies significantly with wavelength and altitude, and it is not sensitive to a change of latitude. The inversion results of each wavelength at different latitudes can be combined, and it can be seen that the 754–769 nm band is preferred for oxygen and temperature detection. Therefore, analyzing the accuracy results of the specific wavelength 757.84 nm at different latitudes, the temperature accuracy can reach 0.1 K in the stratosphere at both low and high latitudes and 0.6–34 K at middle latitudes. The temperature detection accuracy in the mesosphere at each latitude reaches about a dozen K. The deviation of the inversion results at middle latitudes is larger in the thermosphere, and at the other two latitudes, it is about a few dozen K. From the analysis of relative deviation, excluding the deviation of 95–100 km, the deviation of other altitudes is within the ideal range, and the minimum can reach 0. The accuracy of the oxygen number density increases with latitude, and the relative deviation of the middle and high latitudes is around 10–20%. Based on the above results, it is concluded that the technique of starlight occultation exhibits high accuracy for detecting atmospheric parameters in the near space region, and the results lay the technical foundation for the independent development of stellar occultation

    Photo-Fenton Degradation Process of Styrene in Nitrogen-Sealed Storage Tank

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    Using styrene as a proxy for VOCs, a new method was developed to remove styrene gas in nitrogen atmospheres. The effect on the styrene removal efficiency was explored by varying parameters within the continuum dynamic experimental setup, such as ferrous ion concentration, hydrogen peroxide concentration, and pH values. The by-products are quantized by a TOC analyzer. The optimal process conditions were hydrogen peroxide at 20 mmol/L, ferrous ions at 0.3 mmol/L and pH 3, resulting in an average styrene removal efficiency of 96.23%. In addition, in this study, we construct a BAS-BP neural network model with experimental data as a sample training set, which boosts the goodness-of-fit of the BP neural network and is able to tentatively predict styrene gas residuals for different front-end conditions
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