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981.
982.
G. Gabrielli D. Senatra G. Caminati G. G. T. Guarini 《Colloid and polymer science》1988,266(9):823-831
Mixed monolayers of tetradecanol and oleic acid at the water-air interface were studied to provide a static related structure featuring the interface between water and oil of water-dodecane microemulsions.The films of pure components as a function of temperature show a strong area contraction between 25 ° and 30 °C, caused by a change in the head groups hydration. This agrees with similar discontinuities found for some properties of the microemulsion in the same temperature range. At the water-air interface, the composition range of tetradecanol/oleic acid mixtures with the highest thermodynamic stability corresponds to the same stability range of the water-in -dodecane-potassium oleate microemulsions.Adsorption isotherms of tetradecanol and hexanol at the dodecane-water interface were studied to compare the surface behaviour of the two alcohols; the results indicate that the two alcohols have very similar two-dimensional surface phases and adsorption energies. 相似文献
983.
984.
985.
利用红外光谱法、气相色谱法(GC)和色-质联用(GC-MS)技术分析测定了投运一年后的劣质变压器油中硅胶吸附物的呈色成分,分析了硅胶吸附变色的原因。 相似文献
986.
T. V. Chernenko A. I. Glushenkova A. M. Nigmatullaev 《Chemistry of Natural Compounds》2002,38(4):307-309
Lipids from Mediasia macrophylla leaves were studied. Classes of neutral, glyco-, and phospholipids and their fatty-acid composition were determined. The content of chlorophyll and carotinoid pigments in the leaves and lipid extract was found. Essential oil was isolated by steam distillation and contained free and bound fatty acids. 相似文献
987.
988.
Cao X Li Y Jiang S Sun H Cagna A Dou L 《Journal of colloid and interface science》2004,270(2):295-298
Viscoelastic properties of two polymers, partially hydrolyzed polyacrylamide and partially hydrolyzed modified polyacrylamide, widely used in chemical flooding in the petroleum industry, were investigated at three interfaces, water-air, water-dodecane, and water-crude oil, by means of a dilational method provided by I.T. Concept, France, at 85 degrees C. Polymer solutions were prepared in brine with 10,000 mg/l sodium chloride and 2000 mg/l calcium chloride. It has been shown that the viscoelastic modulus increases with the increment of polymer concentration in the range of 0-1500 mg/l at the water-air interface. Each polymer shows different viscoelatic behavior at different interfaces. Generally speaking, values of the viscoelastic modulus (E), the real part (E'), and the imaginary part (E") at the crude oil-water interface for each polymer are lower than at the air-water or water-dodecane interface. The two polymers display different interfacial properties at the same interface. Polymer No. 2 gives more viscous interfaces than polymer No. 1. All the information obtained from this paper will be helpful in understanding the interfacial rheology of ultra-high-molecular-weight polymer solutions. 相似文献
989.
990.
A direct and automatic method has been developed for molecular weight (MW) determination and distribution in crude oils and condensates up to C20 (340°C) by gas chromatography. Chromatographic separation has been achieved with a 50 m OV-1 fused silica capillary column, fitted with a pre-column to eliminate the fraction boiling above 340°C. The internal standard is added for quantification. Approximately 550 peaks have been identified by the use of GC/MS on different paraffinic, naphthenic, and aromatic crude oils or condensate samples. From identification and by correlation with MS group-type analysis, a carbon number and a hydrocarbon group are attributed to each peak or group of peaks. Further molecular weights have been calculated from these groups. A comparison between results from this GC method and cryometry of narrow and wide fractions shows good agreement, within the precision of cryometry. An automatic identification by computer using programmed temperature indices was used for the direct determination of molecular weight. The final report gives weight percentage, molar percentage, and molecular weight for every boiling range group and hydrocarbon group. 相似文献