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111.
TOMÁSbreve BOUBLÍK 《Molecular physics》2013,111(21):3443-3449
The self-consistency (S-C) constraints on the solute chemical potential and equation of state are stated and employed to find corrections to thermodynamic functions in the colloidal limit for the most often used equations of state. It is shown that the S-C approach and Henderson's expression for the contact radial distribution functions yield the same correction term in the case of the Boublik—Mansoori—Carnahan—Starling—Leland (BMCSL) equation of state for hard spheres. For hard sphere (and hard convex body) mixtures a new variant of the equation of state and Helmholtz energy is proposed that fulfils better the self-consistency constraints than the frequently used equations. It is shown that the correction term for Δμ 2 in hard convex body mixtures described by improved scaled particle theory differs from that for BMCSL only by the non-sphericity parameter. For the Kolafa—Boublik and modified scaled particle theory versions the correction terms are more complex. 相似文献
112.
The paper studies the economy and ecology of sheep farming at the farm level in a Nordic context, with a crucial distinction between the outdoors grazing season and the winter indoors feeding season, and where climate conditions fix the length of the grazing season. Two different categories of animals, ewes (adult females) and lambs, and one plant species are included in our ecological model. The farmer is assumed to maximize present‐value profit where the revenue is made up income from meat and wool production. We find that livestock cycles may represent an optimal management policy. We also show that in a possible steady state with a constant number of animals and constant vegetation quantity, slaughtering either only lambs or only ewes is optimal. 相似文献
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115.
MANUEL GUTIÉRREZ-PICHEL DAVID ATTWOOD PABLO TABOADA VÍCTOR MOSQUERA 《Molecular physics》2013,111(23-24):3455-3465
Apparent molal volumes and adiabatic compressibilities of aqueous solutions of the amphiphilic antidepressant drugs imipramine and desipramine hydrochlorides have been determined from density and ultrasound velocity measurements in the temperature range 288.15—313.15 K in buffered solution of pH 3.0 and 5.5. Critical concentrations for aggregation of these drugs were obtained from inflections on the plots of the sound velocity against drug concentration. Positive deviation from the Debye—Hückel limiting law of the apparent molal volume of imipramine provides evidence of limited association at concentrations below the critical concentration over the temperature range studied. Apparent molal adiabatic compressibilities of the aggregates formed by the drugs, calculated by combining the ultrasound velocity and density data, were typical of those for a stacked aggregate. The critical concentration and energy involved in the aggregation process of these drugs have been evaluated using isothermal titration calorimetry. The solvent—aggregate interactions have been discussed from compressibility and calorimetry data. 相似文献
116.
For systems of Kihara molecules with circular cores, the values of the reduced critical constants were determined from the fourth-order virial expansion as functions of the core diameter/thickness ratio. From expressions for the reduced functions both for the oblate and prolate shapes, the values of critical constants of four cyclic hydrocarbons and four branched alkanes were evaluated and compared with the experimental data and values obtained from the perturbation theory. 相似文献
117.
E. CARMONA-NOVILLO J. CAMPOS-MARTÍNEZ M. I. HERNÁNDEZ O. RONCERO P. VILLARREAL G. DELGADO BARRIO 《Molecular physics》2013,111(21):1783-1791
In this work we explore the application of a time-dependent Hartree (TDH) scheme to study the vibrational predissociation of Ne2I2 van der Waals clusters. The present approach is based on equations of motion extracted from the usual variational principle where the Hamiltonian has been previously represented in a set of diatomic vibrational states. The procedure leads to a set of coupled equations for the different modes on each diabatic state with, however, explicit separation between those modes. The application on a problem that inherently requires longtime propagation is shown to be successful. Calculated lifetimes compare well with previous calculations as well as with available experimental data. A more detailed mechanism, as the breath of the angular mode on the different vibrational channels, is better described. 相似文献
118.
Abstract In this study the graft copolymerization of acrylamide (AAm) on swollen poly(ethylene terephthalate) (PET) fibers using cerium ammonium nitrate (CeAN) initiator was investigated. Five organic solvents, dimethylsulfoxide (DMSO), morpholine, acetic acid (HAc), n-butanol, and 1,2-dichloroethane (DCE), were used as swelling agents. DMSO was found to be the most suitable swelling agent. Solvent diffusion into the fibers was observed to increase with treatment time and temperature. The optimum graft yield was obtained when fibers were grafted after having been swollen in DMSO for a period of 1 hour at 140°C. Variation of graft yield with polymerization time and temperature, and monomer, initiator, and acid concentrations were investigated. Graft yields were observed to increase initially with polymerization time, then to level off, and were found to increase up to a certain monomer and Ce4+ concentration, then to decrease slightly. The effect of grafting on such fiber properties as diameter, viscosity, and moisture gain were also investigated. 相似文献
119.
JOAQUÍN BARBERA´ RAQUEL GIME´NEZ NE´LIDA GIMENO MERCEDES MARCOS MARIA DEL CARMEN PINA JOSE´ LUIS SERRANO 《Liquid crystals》2013,40(6):651-661
Copper and palladium complexes of new salicylaldimines derived from 3,4,5-tridecyloxyaniline, 2,3,4-tridecyloxyaniline and 4-decyloxyaniline have been synthesized and characterized. All the ligands bear four or more aliphatic chains with the aim of inducing columnar mesophases at low temperatures. In particular, metal complexes derived from 4-(3,4,5-tridecyloxybenzoyloxy)-salicyliden-3,4,5-tridecyloxyaninile display rectangular columnar mesophases at (or near) room temperature. These mesophase assignments have been confirmed by X-ray diffraction. A significant decrease of the melting points of the compounds is observed in the tridecyloxyaniline derivatives compared with those of similar complexes derived from mono- or di-decyloxyaniline. 相似文献
120.
M. Zamora T. López R. Gómez M. Asomoza A. GarcÍa-Ruiz X. Bokhimi 《Journal of Sol-Gel Science and Technology》2004,32(1-3):339-343
The effect on titania of doping with lithium and rubidium titania gels has been studied in samples prepared with titanium (IV) tetra-n-butoxide co-gelling with the alkaline metal precursors. Titania and doped titania were characterized by X-Ray diffraction, which showed that the catalysts were nanostructured. In samples calcined at 400°C, the crystallite size of the anatase phase was 17 and 14 nm, and 78 and 38 nm for samples calcined at 600°C, for Li/TiO2 and Rb/TiO2, respectively. The specific surface areas of doped samples (400°C) are lower in Li/TiO2 (90 m2/g) than in Rb/TiO2(125 m2/g). Evaluation of their basic properties has been carried out in the acetone condensation reaction. It was found that the activity strongly depended on the Li and Rb ionic radii. 相似文献