Excess enthalpies of (ethanol + methyltert-butyl ether + a C6-hydrocarbon) ternary systems at 25°C

Excess molar enthalpies, measured at 25°C in a flow microcalorimeter, are reported for the three ternary systems [ethanol + methyl tert-butyl ether + (n-hexane or 2,3-dimethylbutane, or cyclohexane)]. Smoothing equations were fitted to the results and used to construct constant excess enthalpy contours for each of the systems.     

Excess molar volumes and isentropic compressibilities of binary liquid mixtures containing n-alkanes at 298.15 K

Excess molar volumes (V ^E) and deviation in isentropic compressibilities (Δβ _s) have been investigated from the density ρ and speed of sound u measurements of six binary liquid mixtures containing n-alkanes over the entire range of composition at 298.15 K. Excess molar volume exhibits inversion in sign in one binary mixture, i.e., n-heptane + n-hexane. Remaining five binary mixtures, n-heptane + toluene, cyclohexane + n-heptane, cyclohexane + n-hexane, toluene + n-hexane and n-decane + n-hexane show negative excess molar volumes over the whole composition range. However, the large negative values of excess molar volume becomes domainant in toluene + n-hexane mixture. Deviation in isentropic compressibility is negative over the whole range of composition in the case of all the six binary mixtures. Existence of specific intermolecular interactions in the mixtures has been analyzed in terms of excess molar volume and deviation in isentropic compressibility.     

基于开关信号理论的三值IZL单变贵电路设计

本文应用开关信号理论的基本思想，分别用开关变量及三值信号变量来描写IZL电路!}?地开关晶体管的开关状态与三值电流信号·联结这两类变量的!}J比较运算和接地运算则用于描写电路内部开关元件与信号的相互作用过程，从而引入了适用于IzL电路的接地电流开关理论.基于该理论，本文对几类重要的三值IzL单变量电路进行了设计，结果表明，借助该理论能获得较简单的电路设计.     

Dielectric behaviour of ketone-amine binary mixtures at microwave frequencies

Values of dielectric constant (ε′) and loss factor (ε″) have been experimentally determined for binary liquid mixtures of ethyl methyl ketone+ethylenediamine and methyl isobutyl ketone+ethylenediamine at 9.44 GHz microwave frequencies at 30°C. The values ofε′ andε″ have been used to evaluate the molar polarization, apparent polarization and the excess permittivities. Excess refractive index, viscosity and activation energy of viscous flow have also been estimated. These parameters have been used to explain the formation of 1:1 complexes for both the systems.     

A new density-dependent mixing rule for the SRK equation of state

A new procedure for obtaining density-dependent mixing rules is applied to the Soave-Redlich-Kwong equation of state. The result is a one-parameter local-composition mixing rule which adequately represents the nonidealities possible in dense fluid mixtures but approaches the classical mixing rule at low densities. A three-parameter version of the mixing rule is also presented which allows for the local-composition effect in the low density limit. The expressions are tested with the Soave-Redlich-Kwong equation of state. Results for vapor-liquid and gas-liquid systems are discussed.     

Universal Differential Calculus on Ternary Algebras

General concept of ternary algebras is introduced in this article, along with several examples of its realization. Universal envelope of such algebras is defined, as well as the concept of tri-modules over ternary algebras. The universal differential calculus on these structures is then defined and its basic properties investigated.     

INS investigation on disaccharide/H2O mixtures

New Inelastic Neutron Scattering findings on homologues disaccharides (C₁₂H₂₂O₁₁)/H₂O mixtures are presented. The comparison among the spectra of trehalose, maltose and sucrose/H₂O mixtures, besides evidencing a different destructuring effectiveness on the H₂O hydrogen bond network, and hence different cryoprotectant properties, shows a higher ‘crystallinity’ degree for the trehalose/H₂O system which accounts for its higher ‘rigidity’. This result justifies the better cryptobiotic action of trehalose in respect to maltose and sucrose.     

Thermal analysis of the selenites of the ternary system Nd2O3-SeO2-H2O AT 100°C

The solubility isotherm of the system Nd₂O₃-SeO₂-H₂O at 100°C was studied and drawn. All possible selenites of neodymium were obtained and characterized. Thermal decomposition of all phases in the system was studied and its mechanism was described. This revised version was published online in August 2006 with corrections to the Cover Date.     

Densities,excess molar volumes,and partial molar volumes for binary mixtures of water with monoethanolamine,diethanolamine, and triethanolamine from 25 to 80°C

We have measured densities of binary mixtures of water with monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) over the full range of compositions and over the temperature range from 25 to 80°C. Results of these measurements have been used in calculating excess molar volumes and partial molar volumes. Knowledge of the volumetric properties of these mixtures is useful in connection with industrial treatment of acidic gases; derived excess molar volumes and partial molar volumes can be used as a basis for understanding some of the molecular interactions in water-organic mixtures.Presented at the Symposium, 76^th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65^th birthday.     

Simulation of concentration changes in complex volatile mixtures during evaporation by using gas chromatography

Summary A method is proposed for the simulation of weathering and aging of mixtures of organic components of similar polarity, e.g. gasolines. Semi-empirical equations are derived and tested which correlate the composition of samples after evaporation with the composition of the original material. In this way, changes in composition during partial evaporation of the liquid mixture can be predicted. In the context of forensic investigations this procedure can be helpful for tracing back the composition of the liquid remaining to that of the original unweathered liquid. To perform this simulation, the relative volatilities of the individual components in the mixture have to be known. These are determined by gas chromatographic retention data simultaneously with the concentrations of the volatile components. The paper evaluates the semi-empirical equations employed and discusses the influence of the simplifying assumptions introduced on the accuracy of the simulation.