ISSN:0005-9021    

DOI:10.1002/bbpc.19810850502

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractData of the temperature dependence of partial molar quantities (heat capacity and temperature derivative of partial molar volume) of perfluoromethylcyclohexane and carbon tetrachloride in a mixture of critical composition are reported. It is found that for both components the signs of the critical amplitudes of the partial molar quantities are positive. Using these data a thermodynamic relation between the critical amplitudes of specific head capacity, partial molar heat capacity, temperature derivative of specific volume and temperature derivative of partial molar volume is tested. — Analogous experiments on the system isobutyric acid/water give results which are characteristically different: (1) the sign of the critical amplitude of the partial molar heat capacity of isobutyric acid is positive whereas that of water is negative, (2) the opposite is true for the sign of the critical amplitude of the temperature derivative of the partial molar volume of the two components. The characteristics of the system isobutyric acid/water are interpreted by assuming that in a critical mixture, approaching the critical point from the one fluid phase region, the extent of hydrogen bonding between water molecules in the vicinity of the hydrophobic part of isobutyric acid molecules increases with decreasing temperature difference from the critical temperatur

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850503

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe paper presents experimental results of the electrical conductivity σ, the equation of state data and different related properties such as excess volumes of mixingVExand partial molar volumes V̄Infor dilute amalgams of In as a function of pressurep. temperatureTand compositionXInto 2700 bar, 1900 K and 2.85 at‐% In, respectively. Particular attention is given to the behaviour of these properties in the metal‐nonmetal transition range and close to the critical point of pure Hg. It is found that the divergence of the compressibility χTof pure Hg at the critical point is reflected in the behaviour ofVEx, V̄Inand in the concentration dependence of the conductivity. The limiting values of the negative partial molar volume V̄Inand of for infinitely dilute solutions become extremely large as the critical point of pure Hg is approached. — An attempt is made to separate the different effects of temperature, volume and concentration and to analyze the data in terms of existing models for the electrical transport in expanded Hg and the critical behaviour of fluid dilute

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850504

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractAn isoperibol room‐temperature calorimeter has been constructed to measure the spontaneous reactions of BaO and Na2O with MoO3and V2O5after ignition. With this calorimeter, the heats of formation from the component oxides have been determined for BaMoO4, BaV2O6, Na2MoO4, Na2Mo2O7, NaVO3, Na4V2O7and Na3VO

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850505

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe twin cascaded Knudsen cell makes possible improved comparative measurements of effusion processes on sample pairs exhibiting widely differing evaporation temperature ranges. Investigating the polymorph system Arsenolite‐Claudetite no significant differences in the evaporation behaviour of both polymorphs can be foun

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850506

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe enthalpy of binding of ethidiumbromide (EB) to double‐ and single‐stranded DNA of two different species and to apurinic acid has been measured by means of an isothermal mixing calorimeter. Equilibrium dialysis served as a tool to determine the extent of binding of EB. — At 5, 20, and 35 °C the binding enthalpies were −20.3, ‐23,6, and −33.5 kJ/mol EB, respectively, for the binding to single‐stranded calf‐thymus DNA (ssCT) in SSC‐buffer and −21.4, 28.5, −36.4 kJ/mol EB for the binding to dsCT. In a tenfold diluted buffer the values were ‐39.4, −62.8, −72.0 kJ/mol EB for ssCT and −21.4, −3

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850507

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe enthalpy of binding of different amines and oligopeptides to double‐ and single‐stranded DNA has been measured by means of an isoperibolic mixing calorimeter. Measurements were performed in diluted Citrate buffer at 25 °C. The binding of the peptides to double‐stranded DNA did not result in any measurable enthalpy change (except LysTrpLys), binding of the peptides could be demonstrated by equilibrium techniques. Binding to single‐stranded DNA yielded enthalpies up to ‐30 kJ/mol of peptide bound. The binding enthalpy of some of the peptides depends markedly of the degree of binding, which has been determined by equilibri

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850508

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe reciprocal solubility of ethylene and polyethylene‐wax was determined at temperatures from 383 to 473 K under pressures up to 200 MPa. Besides the cloud curve, the shadow and the coexistence curves have been measured. The miscibility gap is present in the whole range of concentration for pressures under 65 MPa. The heterogeneous region increases slightly with rising temperature, the critical curve remains practically unchanged with varying temperature. The solubility of ethylene in the polymer could be described with good accuracy on the bases of Henry's law and the theory of Flory‐Huggins for solutions of polymers. This description can be made by means of a simple expression for the temperature and pressure dependency of Flory's parameter. The phase behaviour of the investigated system is compared with experimental measurements and with those of other authors carried out on mixtures with ethylene and alkanes having lower molecular weig

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850509

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe paper reports new absolute measurements of the viscosity of hydrogen and its binary, gaseous mixtures with neon, argon and krypton at 25 °C and 35 °C and at a pressure of 0.1 MPa. The measurements were carried out in a high‐precision oscillating‐disk viscometer and their accuracy is estimated as one of ±0.2%. — The results have been compared with predictions based on recent intermolecular pair potentials for the interactions of hydrogen with the monatomic gases derived from spectroscopic and molecular beam studies. The calculations, which have been carried out with second‐order kinetic theory expressions, are not entirely consistent with the experimental results. The experimental results have been employed to determine binary diffusion coefficients for the three systems. The viscosity data have also been employed to predict the thermal conductivity of the mixtures with the aid of the most accurate kinetic theory formulae available for systems containing polyatomic components. A comparison with accurate thermal conductivity data indicates that the equations, which are first‐order approximations, are not sufficiently accurate for systems containing components of widely di

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850510

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe influence of intermolecular elastic (T2processes) and inelastic (T1processes) interactions on the population relaxation and phase relaxation of a specific molecular mode is studied in terms of a two mode model. Therein one mode (K‐level system) is assumed to undergoT1andT2relaxation processes as a consequence of its coupling to a thermal reservoir while the second mode (N‐level system) is not explicitly damped but is coupled to the first one. The quantum statistical equations of motion for the coupled two‐mode system are solved numerically with a special integration scheme in which the damping is considered in first order and the coupling of the modes in infinite order. Energy relaxation and dephasing of theN‐level system are studied as functions of the external relaxation behaviour and of the coupling between the modes. A dynamical decoupling of the two modes is found with decreasing intermolecular dephasing

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850511

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY