Excess Molar Volume and Viscosity of Isobutyric Acid + Water Binary Mixtures Near and Far Away from the Critical Temperature

The excess molar volume V^E, shear viscosity deviation Δη and excess Gibbs energy of activation ΔG^∗E of viscous flow have been investigated by using density (ρ) and shear viscosity (η) measurements for isobutyric acid + water (IBA+W) mixtures over the entire range of mole fractions at five different temperatures, both near and close to the critical temperature (2.055K ≤ (T−T_c)≤ 13.055K). The results were also fitted with the Redlich–Kister equation. This system exhibited very large negative values of V^E and very large positive values of Δη due to increased hydrogen bonding interactions and correlation length between unlike molecules in the critical region and to very large differences between the molar volumes of the pure components at low temperatures. The activation parameters ΔH^∗ and ΔS^∗ have been also calculated and show that the critical region has an important effect on the volumetric properties.     

天然和人工培植红景天挥发油的对比研究

应用ＧＣ－ＭＳ和ＧＣ－ＩＲ两种联机法对比研究了天然和人工培植红景天挥发油、分别鉴定出２７个和２４个化合物。ＭＳ给出结构信息和ＩＲ给出官能团信息相结合，提高了分析测试复杂样品的可靠性。     

Production of N,H, and NH active species in N2-H2 dc flowing discharges

Densities of N, H, and NH active species have been detected by laser-induced fluorescence (LIF) in N₂-xH₂ dc flowing discharges. A peak value of N atom densities far x = 0.2–0.5% and a plateau value of H atom densities between x = 1% and 90% in post-discharge conditions (0.05 sec, p = 2 torr) has been found. Comparison between LIF measurements of N atoms and the trend of the N₂(B, v = II) population shows that the emission from this state can be used for monitoring N atoms. The NH radical has only been detected inside the discharge region.On leave from Instituto Tecnológico de Aeronáutica, CNPq, Brazil.     

Volumetric Properties of Ternary-Pseudobinary Mixtures Containing Benzene and Cyclohexane

Densities have been measured as a function of composition for ternary-pseudobinary mixtures of [(benzene + toluene or methylcyclohexane) + (cyclohexane + toluene or methylcyclohexane)] by means of a vibrating-tube densimeter at atmospheric pressure and the temperature 298.15 K. The excess molar volumes, V_m^E, were calculated from the densities and correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show the third component, toluene and methylcyclohexane, influences the interaction between benzene and cyclohexane.     

NaCl(或KCl)-CH3OH-H2O体系的摩尔电导

CHaOH－HzO体系具有非常特殊的性质，同时在工业生产及临床治疗方面有着十分广泛的应用，文献中有大量地从不同角度就这类体系进行研究的报道．然而，就N3CI及KCI－CH30H－H20体系的电导研究而言，文献中仅有关干KCI－CH30H－H20（间隔20％CH30H）的部分研究工作．作为全面、系     

非缔合二元有机液体混合物过剩热容的测定与计算

溶液的过剩热容是热力学的重要函数，对其测定与研究具有理论与实际意义．过剩热容不仅可检验溶液中分子间的相互作用，并可利用其计算混合物的热容．本文报告了用微量热仪对环乙烷一本等七个二元物系全浓度范围内在29815K、常压下过剩热容CEp进行的测定工作，上述体系是由具有     

PVC DISULFIDE AS CATHODE MATERIALS FOR SECONDARY LITHIUM BATTERIES

PVC disulfide (2SPVC) was synthesized by solution crosslink and its molecular structure was confirmed by infrared spectrum. 2SPVC's specific area is 36.1 m2·g-1 tested by stand BET method, and granularity experiment gives out the particle size of d0.5= 11.3μm. With SEM (Scanning Electron Microscope) experiment the surface morphology and particle shape of 2SPVC were observed. Cyclic voltammetry (scan rate: 0.5 mV·s-1) shows that 2SPVC experience an obvious S-S redox reaction in charge-discharge process. When 2SPVC was used as cathode material for secondary lithium battery in a 1 mol·L-1 solution of lithium bis(trifluoromethylsulfonyl) imide (Li(CF3SO2)2N) in a 5:45:50 volume ratio mixture of o-xylene (oxy), diglyme (DG) and dimethoxymethane (DME) at 30℃, the first discharge capacity of 2SPVC is about 400.3 mAh·g-1 which is very close to its theoretical value (410.5 mAh·g-1) at a constant discharge current of 15 mA·g-1. It can retain at about 346.1 mAh·g-1 of discharge capacity after 30 charge-discharge cycles. So 2SPVC is a very promising cathode candidate for rechargeable lithium batteries.     

A view and a review of the melting of alkali metal halide crystals

Summary A representational model, proposed to account for the physical changes that accompany the melting of alkali halides, was described in Part 1 [1]. The liquid is portrayed as undergoing continual dynamic structural reorganization of its constituent ions between individual small domains, zones of various regular, crystal-type arrays. These alternative arrangements are stabilized by the enthalpy of melting, which, in liquids, relaxes the restriction for solids that only the single, most stable, crystal structure can be present. The dynamic character of the melt accounts for its fluid character and the loss of long-range order [1, 2]. This model is extended here to consider the phase diagrams of binary, common ion, alkali halide mixtures comprehensively reviewed in [3]. Factors determining whether each of these yields a eutectic, or a solid solution, on cooling are discussed and several trends in the 70-phase diagrams are identified. Eutectic formation, involving maintenance of the liquid state below the melting points of the pure components, is ascribed to the participation, in an extended dynamic equilibrium, of additional domains having the regular structures characteristic of double salts. The known crystalline double binary halides [3], Li/Cs or Rb/F, Cl, Br or I, melt at temperatures well below those of the simpler pure component salts. It is concluded that the set/liq model for melting, proposed in [1, 2], accounts for some important properties of the phase diagrams presented in [3].     

Chemical equilibrium model for the thermodynamic properties of mixed aqueous micellar systems: Application to thermodynamic functions of transfer

Mixed micelles can be formed in water between various pairs of hydrophobic solutes such as surfactants, alcohols and hydrocarbons. These systems can often be studied through the thermodynamic functions of transfer of one of the solutes, usually kept near infinite dilution, from water to an aqueous solution of the other solute. When mixed micelles are formed, these functions change significantly, and often go through extrema, in the region where the binary system micellizes or undergoes some microphase transition.Three main effects are responsible for the observed trends: pair-wise interactions between both solutes in the monomeric form, a distribution of the reference solute between the aqueous and micellar phases and a shift in the monomer-micelle equilibrium in the vicinity of the reference solute. Simple equations can be derived for these three effects which can account for the sign and magnitude of the observed trends using parameters which are derived for the most part from the two binary systems.     

Densities,Ultrasonic Speeds,Viscosities and Refractive Indices of Binary Mixtures of Benzene with Benzyl Alcohol,Benzonitrile, Benzoyl Chloride and Chlorobenzene at 303.15 K

Densities,ρ, ultrasonic speeds, u, viscosities,η, and refractive indices, n, of pure benzene, benzyl alcohol (BA), benzonitrile (BN), benzoyl chloride (BC), chlorobenzene (CB) and their thirty six binary mixtures, with benzene as common component, were measured at 303.15 K over the entire mole fraction range. From these experimental data the values of deviations in ultrasonic speed, △u, isentropic compressibility, △k_s,excess acoustic impedance, Z^E, deviation in viscosity, Dh, and excess Gibbs free energy of activation of viscous flow, G^*E, and partial molar isentropic compressibility, Kφ,2⁰ of BA, BN, BC and CB in benzene were computed. The variation of these derived functions with composition of the mixtures suggested the increased cohesion (molecular order) in the solution and that interaction (A-B)＞(A-A) or (B-B).Moreover, theoretical prediction of ultrasonic speed, viscosity and refractive index of all the four binary mixtures was made on the basis of empirical and semi-empirical relations by using the experimental values of the pure components. Comparison of theoretical results with the experimental values was made in order to assess the suitability of these relations in reproducing the experimental values of u, η and n. Also, molecular radii of pure liquids and the average molecular radii of binary mixtures were evaluated using the corresponding refractive indices of pure liquids and binary mixtures. The average molecular radii of binary mixtures were found to be additive with respect to mole fraction of the pure component.