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61.
A novel approach was introduced to modeling solute retention in the liquid chromatography systems, employing silica-based aliphatic chemically bonded stationary phases of the cyano, reversed-phase C8 and reversed-phase C18 types, and the mixed binary eluents most frequently used in the reversed-phase and normal-phase chromatography modes (i.e. using the methanol-water and the 2-propanol-n-hexane liquid mixtures, respectively). This approach takes notice of the mixed (adsorption/partition) mechanism of solute retention, in which both, the adsorptive and the dispersive forces contribute to the overall energetics of this process. Performance of our new model was compared with that of the widely recognized and on a routine basis applied Schoenmakers approach, and it was found out that both models perform with a practically equal and outstanding accuracy. 相似文献
62.
Summary An attempt was made to apply a low-activity chromatographic layer (Whatman 2) and a non-polar mobile phase (decalin) in studying the self-association of higher fatty alcohols. The obtained results showed a satisfactory, semi-quantitative agreement with IR spectroscopic data and theoretical considerations and calculations. Usefulness of the complementary paper chromatographic investigations can be considered as complementary investigations when setudying the self-association of higher fatty alcohols. 相似文献
63.
Investigations into the influence of ultrasound on the catalytical properties of chromium gels are presented. The changes of the EPR spectra and surface concentration of Cr on the sixth oxidation degree of certain preparations are described. These changes are then related to the increase in the velocity in the test reaction of H2O2 decomposition and the increased yield of cyclohexane dehydrogenation when the insonated preparations are used as catalysts. 相似文献
64.
Byszewski P. Kowalska E. Diduszko R. Aleksiyko R. Berkowski M. Fink-Finowicki J. Kapuśniak J. 《Journal of Thermal Analysis and Calorimetry》2001,65(2):545-551
The solid solution crystals, La1–xNdxGaO3 and La1–xPrxGaO3 have been studied by differential scanning calorimetry method; the crystals exhibit the first order phase transition, the
temperature of the transition linearly increases with the concentration of Pr or Nd. The structure of the crystals has been
determined by X-ray diffraction. The correlation between the phase transition temperature and crystalline structure at the
temperature of the phase transition in both solid solution families is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
65.
66.
Alexander Herlert Christopher Borgmann Daniel Fink Christian Holm Christensen Magdalena Kowalska Sarah Naimi 《Hyperfine Interactions》2011,199(1-3):211-220
The influence of space charge on the mass selection of ions stored in a Penning trap was investigated with the ISOLTRAP experiment at CERN/ISOLDE. A mixture of 85,87Rb?+? ions has been used to probe the change of the experimental parameters, e.g. frequencies and amplitudes of the radiofrequency excitations, as a function of the number of ions present in the trap. 相似文献
67.
Dorota Kowalska Magdalena Kostecka Katarzyna Tarnowska Boleslaw Kowalski 《Journal of Thermal Analysis and Calorimetry》2014,115(3):2063-2070
Goose fat (GF) and rapeseed oil (RSO) 2:3 m m?1 blend was enzymatically interesterified at 60 °C with and without microwaves assistance. As the catalyst, a commercial preparation of the immobilized lipase from Rhizomucor miehei (Lipozyme RM IM) containing 2 % of water was used, and the catalyst load was 8 % in each case. The starting mixture and the interesterified products were separated by column chromatography into pure triacylglycerols fraction (TAG) and a non-triacylglycerol fraction, which contained free fatty acids (FFA), mono- and diacylglycerols (MAG and DAG). The oxidative stabilities of fats studied and TAG derived from them were assessed by Rancimat at 100 °C and by pressure differential scanning calorimetry (PDSC) under oxygen at 110–140 °C. Interesterification reduced the oxidative stability of GF and RSO blend. The main factors influenced on the oxidative stabilities of fats studied were concentrations of tocopherols and the presence of FFA, MAG and DAG. The structures of TAGs were of minor importance. From the resulting PDSC exotherms, their times to reach the onset (τ on) and peak maximum (τ max) were measured and used for calculations of parameters of the Arrhenius type kinetics for thermaloxidative decomposition of fats studied. 相似文献
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69.
The aim of the study was to determine the optimal conditions, that is, the content of sesame oil and the amount of carboxymethylcellulose, to obtain stable dispersion systems. Emulsions were stored under different temperature conditions. For this purpose, six emulsions were prepared and their stability was examined empirically using techniques including particle size analysis, optical microscopy, and the Turbiscan test. The emulsion containing 40 g of oil and 0.6 g of thickener had the highest stability. No destabilizations in whole the range of stored temperature were observed for the emulsion with that composition. Emulsion was stable as well at cool temperature as at extreme environment (40°C). Nowadays, the use of O/W emulsions based on vegetable oil is continuously increasing. To date, sesame oil has been used mainly for direct consumption. The present work indicates a novel possibility for use of sesame oil as the fat base of an emulsion system. Besides, the study gave information about parameters of long-term stability emulsion what is the key in the quality of the dispersion systems. This knowledge is necessary for the industry in order to avoid destabilizing processes occurring in a new product. 相似文献