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Summary The retention diagrams of benzene, toluene, ethyl benzene, chloro benzene, n-propyl benzene, isopropyl benzene, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate and isoamyl acetate on the polycaprolactone were plotted at temperatures between 70 and 140oC by inverse gas chromatography technique. Percent crystallinity of polycaprolactone were obtained at temperatures below melting point from the retention diagrams of benzene, toluene and ethyl benzene. It was concluded that the data obtained by inverse gas chromatography were comparable those of obtained by differential scanning calorimetry. Specific retention volume, Vgo, Flory-Huggins polymer-solvent interaction parameters, 12, the weight fraction activity coefficients of the solvents at infinite dilution, 1, effective exchange energy parameters, Xeff were determined. Later, the partial molar heat of sorption, H1,sorp and the partial molar heat of mixing, H1 were obtained from the slope of the logarithm of specific retention volume, Ln Vgo versus 1/T plot and from the slope of the logarithm of the weight fraction activity coefficients, 1versus 1/T plot, respectively.  相似文献   
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Journal of Materials Science: Materials in Electronics - The structure-property relationship of various intermediates formed during the step-wise dwell-in thermal condensation of melamine to g-C3N4...  相似文献   
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The attenuation of radio waves due to rain can be predicted with a good degree of accuracy, provided the rain rate characteristics over the entire path of propagation are known. The attenuation due to rain is usually deduced on the basis of point rain rate, which can lead to inaccuracy in the estimation of attenuation. We use the concept of rate of decay of rain path profile to estimate the attenuation due to rain. The attenuation has been deduced at 11GHz and 13.4 GHz for 56 elevation angle by using the theory of decay rate of rain path profile, its controlling factor, gamma, and rain rate distribution over Delhi, a tropical station in India. The theoretically-estimated attenuation is compared with observed values, as well as with values obtained using the International Radio Consultative Committee (CCIR) method. The CCIR model is found to overestimate the attenuation.  相似文献   
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Summary Polystyrene networks were synthesized by free radical polymerization of styrene in the presence of dibenzoyl peroxide as an initiator, divinylbenzene as a crosslinker at 50 °C in toluene under nitrogen atmosphere. The swelling behavior of the synthesized polystyrene networks were studied at different temperatures in methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tert-butyl acetate, and isopentyl acetate. Equations were given for the variation of the polymer-solvent interaction parameter, χ12, as a function of reciprocal absolute temperature in the temperature range from 25 to 75 °C. Polystyrene networks were swollen in linear polystyrene solutions in toluene of different concentrations. Linear polystyrene samples were almost monodisperse and of high molecular weight. The equilibrium swelling degrees were evaluated using the Flory-Rehner theory. The relation of volume swelling ratio, qv, to the volume fraction of the linear polymer in solution, φ, was evaluated and characterized by interaction parameter of crosslinked polystyrene with linear polystyrene, χ23. The parameter χ23 was found around zero as expected from mixtures of similar chemical structures by extrapolating the values of χ23 at tested concentrations to zero solvent concentration.  相似文献   
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Journal of Materials Science: Materials in Electronics - Graphitic–carbon nitride (g–C3N4)-based zinc oxide (ZnO) nanocomposite (ZnO/g–C3N4) is synthesized via...  相似文献   
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