ISSN:0005-9021    

DOI:10.1002/bbpc.19890930702

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

年代:1989

数据来源: WILEY

摘要:

AbstractWe report the first ellipsometric measurements of the optical constants, refractive indexnand absorption coefficientk, for a fluid system at high temperatures, i.e. salt rich KxKCl1‐xsolutions up to 800°C. The applicability and realization of the ellipsometric technique under these experimental conditions is described in detail. First data of the optical conductivity σ (ω,x) and the real part of the dielectric function ϵ1(ω,x) are presented. In a qualitative discussion of these results emphasis is given on the NM‐M transition region. The behaviour of σ (ω,x) in the IR‐region indicates the occurrence of metal clustering approaching the NM‐M transition. From the dielectric anomaly of ϵ1(x) it is concluded that the onset of metallic behaviour is well separated from the consolute composition of the critical point of liquid‐liq

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930703

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe phase diagram of the quasiternary system ZnkHg(1‐k)SelTe(1‐l)was investigated by X‐ray diffraction and DTA measurements. The phase diagrams of the quasibinary subsystems were recalculated using the interaction parameters determined from the isothermal quasiternary sections. The subsolidus region of the quasiternary system shows an extended miscibility gap inspite of complete solid solutions on the quasibinary edges. The tie line field is fan shaped converging on the ZnSe corner of the phase square. The enthalpies of pair formation in the sublattices are calculated using the model of 4‐particle‐clusters. It is also shown, that the assumption of random distribution for the clusters is a rather good approximation for the calculation of the quasiternary phas

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930704

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

年代:1989

数据来源: WILEY

摘要:

AbstractMembranes / Nonequilibrium Phenomena / Streaming Potential / Thermodynamics / Transport PropertiesThe streaming potential Δϕ which arises between the uni‐univalent electrolyte solutions of the same concentration separated by nafion 125 membrane in the presence of a pressure difference ΔPapplied across the membrane has been studied. Different electrolytes have been studied, namely NaCl, LiOH, NaOH, KOH and CsOH. — The quantity Δϕ/ΔPincreases in the order Li>Na>K>Cs. According to the non‐equilibrium thermodynamic theories the ratio (Δϕ/ΔP)/Jv/I), withJv (volume flow)/I(electrical current flow) the electroosmotic quantity, a

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930705

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe isothermal transport coefficients describing the NaCl, volume and water osmotic flows across Nafion membranes are studied. These transport coefficients and others already reported are used to obtain theLijphenomenological coefficients related to the flows of ions and water in the membrane.

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930706

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

年代:1989

数据来源: WILEY

摘要:

AbstractEmpirical correlations between ionic mobilities and parameters characteristic of the solvent molecules motions for a variety of single ions and 1‐1 electrolytes at infinite dilution in 19 one‐component solvents and 8 aqueous‐nonaqueous mixed solvents are found, presented and discussed. The parameters are the self‐diffusion coefficient, the dipole relaxation time, the rotational correlation time of various NMR vectors, and the residence time of solvent molecules in the first ion solvation shell. The residual friction coefficients are considered in a more theoretic

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930707

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

年代:1989

数据来源: WILEY

摘要:

AbstractDensities of solutions of NaCl, NaI, KCl, KBr, and CsCl in three mixtures containing 10 wt% (3.22 mol%), 20 wt% (6.98 mol%) and 30 wt% (11.39 mol%) urea in water have been measured at 333.15 K using the magnetic float densitometer. The apparent molal volumes of the electrolytes calculated from the experimental data were extrapolated to infinite dilution by means of the Masson equation. The ionic partial molal volumes of alkali‐metal and halide ions have been estimated. The partial molal volumes of transfer of ions from water to water‐urea mixtures were separated into the two components: V̄0elect(tr)and V̄0disord(tr). The effect of urea and temperature on V̄0elect(tr)and V̄0disord(tr)in the temperature range 298.15–333.15 K is

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930708

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

年代:1989

数据来源: WILEY

摘要:

AbstractIn alkaline electroless copper solutions with formaldehyde as reducing agent, side reactions between formaldehyde and hydroxide occur. In solutions of formaldehyde and sodium hydroxide below 70°C the only reaction found is the Cannizzaro reaction. The rate constant of this reaction was determined at different temperatures, yielding an activation energy of 87 kJ·mol−1. An increase of Na+concentration leads to an increase of the rate of this reaction. The nature of the anion had no effect. Above 70°C a second reaction proceeds: aldol condensation. Oxygen suppletion inhibits the aldol condensation. Analyses of continuously operating electroless copper solutions showed that the kinetics found in alkaline HCHO solutions could be applied directly to real plating solut

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930709

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe density of trifluoromethane has been measured from 126 to 332 K and up to 1000 bar. The results have been correlated in terms of the Strobridge equation of state, and compared with results from the literature. The ability of other semitheoretical equations of state to fit the data has been tested, as well as a variational theory. The spinodal curve has been estimated from the expansivity data.

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930710

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

年代:1989

数据来源: WILEY

摘要:

AbstractAbsorption spectra of xanthone have been measured in polyethylene film, a 1:1 mixture of methanol and ethanol, a 1:1 mixture of methylcyclohexane and isopentane (MP) at various temperatures. It is found that xanthone forms dimer and tetramer in MP at low temperatures. As for the dimer, phosphorescence and its excitation spectra have been observed. From comparison of the observed and the MO calculated results, assignment of the electronic bands has been made. The 0‐0 bands of the first electronic transitions of monomer, dimer, and tetramer in MP are at 334.6 nm (room temperature), 346.7 nm (132 K), and 357.7 nm (101 K), respectively. The structure of the dimer is considered to be a C2sandwich typ

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930711

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

年代:1989

数据来源: WILEY