An extensive grand canonical Monte Carlo (GCMC) simulation combined with quantum mechanics calculations has been conducted to investigate the dependency of the adsorption isotherms, local density profiles, and orientational behaviors of HCFC-22 confined in pillared clays on pore width, porosity, pressure, and the density of the activated sites at 300 K. The calculated results suggest that there are optimal pore width and pressure for adsorption, and the effects of porosity and the activated sites on adsorption are significant at low pressure and become weaker with increasing pressure. A combination of the GCMC simulation and the quantum mechanics calculation results shows that hydrogen atom is the adsorption site of an HCFC-22 molecule adsorbed on the pillared clay walls and most of the molecules in the contact layers orient perpendicularly to the walls in the direction of C 3 H when physical adsorption is predominant, and the orientation changes with increasing pressure.

A modified adjacency matrix was developed to delineate the chemical graph of a compound, in which the element aii along the diagonal of the matrix reflects the numbers of the lone-pair electrons and

A quantitative structure-activity relationship (QSAR) study on inhibitory activities of 1-phenylbenzimidazoles against the platelet-derived growth factor receptor (PDGFR) was carried out in this work, and a QSAR model was developed. It gives an r2 of 0.78 for the training set of 55 active compounds, and an r2 of 0.75 for the test set of 24 active compounds. The new model was further applied to predict inhibitory activities of additional 44 inactive compounds, and very good agreement with experimental observations was obtained. The new model requires only variable connectivity indices and two position indices as input parameters, which is simple and easy to apply. The new model is useful for developing new anticancer drugs, which also demonstrates that the recently developed variable connectivity indices are very useful structural descriptors in the QSAR studies in the fields of pharmaceutics and biochemistry.

In our previous work [J. Mi, C. Zhong, Yi.-G. Li, J. Chen, Chem. Phys., 305 (2004) 37-45], an equation of state (EOS) based on the combination of renormalization group theory (RG) and the statistical associating fluid theory (SAFT) was proposed for describing pure fluid thermodynamic properties both inside and outside critical region, which was extended to binary mixtures in this work. A variety of binary systems were considered in this work, including nonpolar/nonpolar, /polar, nonpolar/associating and associating/associating mixtures. Two adjustable parameters are required by the new EOS for each binary system, which are obtained by fitting the vapor-liquid equilibria (VLE) data at one emperature. The calculated results show that the new EOS gives satisfactory predictions for critical properties as well as the VLE at other temperatures, both inside and outside critical region. This work demonstrates that RG theory is a very useful tool for accurately describing fluid properties inside critical region, and a combination of it with SAFT EOS can lead to a new EOS possessing the advantages of both heories, applicable to the whole phase equilibrium region of binary mixtures.

The open-cell model equation of state (OCM EOS) proposed in the preceding paper by the authors has been extended to polymer-solvent and polymer blend systems, covering a variety properties, including P-V-T relations, the excess volume and enthalpy, the activity of solvents, and phase diagrams. Compared with the well-recognized Simha and Somcynsky EOS, the OCM EOS presents a better description of P-V-T relations and phase diagrams. Besides, through a set of proper binary interaction parameters, good correlation of the excess properties can be achieved. In conclusion, as an improvement over the existing hole theory EOSs, the OCM EOS is capable of describing liquid mixture properties with satisfactory accuracy.