RESUMO
The properties of mixtures of butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], with poly(ethyleneglycol) dimethyl ether, PEO, were described as a function of PEO chain size by molecular dynamics simulations. Both PEO chain size and mixture composition revealed to play a significant role in determining the structure and the dynamics of the fluids. The remarkably higher viscosity observed for mixtures composed by 0.25 mole fraction of PEO was attributed to the increase in the gauche population of OCCO dihedral of the polyether of longer chains. The negative solvation enthalpy (ΔsolH < 0) and entropy (ΔsolS < 0) revealed a favorable CO2 absorption by the neat and mixture systems. The CO2 absorption was higher in neat PEO, particularly considering longer chains. The gas solubility in the mixtures presented intermediate values in comparison to the neat PEO and neat ionic liquid. The CO2 solutions had their structures discussed in the light of the calculated radial and spatial distribution functions.
RESUMO
A comparative study of the performance of multi-sizes of the Mahua Ring inserted following measurement of the uterine cavity and one size of the same ring assigned at random was carried out from November 1984 to September 1985 at two hospitals in Tianjin. The experiences of 800 acceptors were analysed by life-table techniques. At the end of two years, net cumulative first segment continuation rates of the multi-size and one-size Mahua device were 88.0 and 88.2, respectively. The results revealed that there was no significant difference between the groups. It is suggested that to insert one size of the Mahua Ring is as effective as the insertion of many sizes of the Mahua Ring.