Národní úložiště šedé literatury Nalezeno 44 záznamů.  1 - 10dalšíkonec  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Supercritical Fluid Extraction of Sesquiterpene Lactones from Laserpitium archangelica.
Sajfrtová, Marie ; Kraus, V. ; Wimmer, Z. ; Cerhová, Marie ; Vlk, M.
The aim of the work was to describe the SFE of two STLs, archangelolide and trilobolide, from seeds of Laserpitium archangelica (Apiaceae). The objectives consisted in: (a) optimizing, investigating the SFE condition (pressure, temperature and concentration ofmodifier in scCO2) effect on the yield and concentration of STLs in extract, (b) \nDetermination of the SFE kinetics of major components in the extracts and (c) comparing the SFE with pressurised liquid extraction (PLE) and Soxhlet extraction.\n\n\n
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Influence of Water-Ethanol-Modified Supercritical Carbon Dioxide at the Preparation of Crystalline Monolithic TiO2 Aerogels.
Cerhová, Marie ; Sajfrtová, Marie ; Matějová, L. ; Dřínek, Vladislav ; Daniš, S. ; Jandová, Věra
This work is focused on a study of TiO2 aerogel SFC with scCO2 modified by mixture of ethanol and water in a ratio 1:1. The effect of temperature (40-100 °C), pressure (10-30 MPa) and modifie concentration in scCO2 (5-15 wt.%) and the additional drying with pure CO2 on microstructure, purity and textural properties of TiO2 aerogel was investigated. Processed monoliths were characterized by XRD analysis, Raman spectroscopy and N2 physisorption.
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Non-Thermal Crystallization of TiO2 Thin Films using Supercritical Carbon Dioxide Modified by Ethanol-Water Mixture.
Sajfrtová, Marie ; Cerhová, Marie ; Jandová, Věra ; Dřínek, Vladislav ; Matějová, L. ; Daniš, S.
In this work, the scCO2 modified by mixture of water and ethanol was used for a preparation of crystalline and pure nanostructured TiO2 thin films in one step processing. All the experiments were performed over precursor titania thin films prepared by reverse micelles assisted sol-gel method, using hardly removable nonionic surfactant Triton X-114, however, forming uniform nano-domains. The effect of temperature (40-150 °C), pressure (10-30 MPa), modifier composition \n(20, 50 and 80 % w/w of water in ethanol) and concentration inscCO2 (5-15 wt. %) and consumed amount of solvent (50-200 g) on microstructure and purity\nof TiO2 thin films was thoroughly studied by means of Raman spectroscopy, X-ray diffraction, and contact angle measurements.
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Processing of Waste from Wine Industry into Products with Substantial Added Value.
Topiař, Martin ; Cerhová, Marie ; Zachová, Zdeňka ; Sajfrtová, Marie
The aim of this work is to select and optimize extraction methods for the processing of grape cane and wine marc, and design and assemble a functional sample of a multipurpose laboratory unit, combining various extraction techniques (Soxhlet and ultrasonic extraction, maceration, temperature and pressure control), offering thus potential for the treatment of different plant waste.
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Supercritical Fluid Extraction: A Green Method for the Isolation of Valuable Substances from the Various Biological Matrices.
Topiař, Martin ; Sajfrtová, Marie ; Šolcová, Olga ; Hradecký, J. ; Hůrková, K. ; Hajšlová, J.
Supercritical fluid extraction (SFE) using carbon dioxide is a sophisticated technology suitable for isolation of un-polar, high value biological active substances from the various biological matrices. In this study, it was used for the extraction of Magnolia x pruhoniciana flowers and Japonochytrium marinum fungus. Results obtained from the SFE were compared with those from conventional extraction methods. A total number of 37 compounds were identified in the magnolia isolate, from which α-pinene (18 % of peak area), cymene (14 % of peak area), β-pinene (13 % of peak area) and humulene (6 % of peak area) were its main components. Yield of valuable free fatty acids DHA and EPA obtained by the SFE of Japonochytrium marinum was more than 1.5 times higher in comparison with organic liquid extraction using mixture of methanol and dichloromethane.
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Use of Water- And Ethanol-Modified Supercritical Carbon Dioxide for Direct Preparation of Crystalline Monolithic TiO2 Aerogels.
Cerhová, Marie ; Sajfrtová, Marie ; Matějová, L. ; Dřínek, Vladislav ; Daniš, E. ; Jandová, Věra
We studied a combination of supercritical CO2, water and ethanol for the preparation of crystalline and pure nanostructured TiO2 without any thermal processing. The effect of temperature (40-150 °C) and sequence on structural and textural properties was investigated at constant pressure of 30 MPa. The prepared aerogels were characterized with respect to the (micro)structural properties by Raman spectroscopy and X-ray diffraction. The textural properties such as specific surface area, content of mesoporous and volume of microporous were determined from nitrogen physisorption and skeletal density by helium pycnometry measurements.
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Supercritical Fractionation of Turmerones from Turmeric rhizomes by Sorption – Comparison of Different Types of Silica Gel.
Topiař, Martin ; Sajfrtová, Marie ; Sovová, Helena
Aim of this study was to find the optimal type of silica gel for the separation of turmerones from the turmeric SFE isolate and their concentration in eluted fractions.
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The Effect of Experimental Design on Crystal Size of TiO2 Thin Films Prepared by Using Modified Supercritical Carbon Dioxide.
Cerhová, Marie ; Sajfrtová, Marie ; Matějová, L. ; Dřínek, Vladislav ; Daniš, S. ; Jandová, Věra
In this work, the method using pure and modified supercritical carbon dioxide was tested to prepare a set of crystalline TiO2 thin films deposited on soda-lime glass. Precursor solution for TiO2 films was prepared by a templated sol-gel method in the reverse micelle environment. Simple approach or combination of several steps performed at different temperature (40-150 °C) and solvent composition was applied at pressure 30 MPa. Water, ethanol and water : ethanol (1:1) mixture were added into supercritical CO2 as modifiers at concentration 10-30 wt.%. The effect of extraction design on microstructure and purity of TiO2 thin films were examined.
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