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41.
Przemyslaw Los Andrzej Lasia Hugues Mnard Louis Brossard 《Journal of Electroanalytical Chemistry》1993,360(1-2)
The hydrogen evolution reaction (HER) was investigated on a lanthanum-phosphate-bonded nickel (LPBN) powder electrode in 30 wt.% NaOH at 70°C using ac impedance and steady-state polarization techniques. Circuits containing one or two constant-phase elements (CPEs) in parallel with a resistance and corresponding to fractal and porous electrode models were tested in order to interpret the ac impedance data. The experimental impedance spectra were well described by the porous electrode model and the circuit containing two CPEs. The results obtained from the ac impedance and steady-state measurements allowed the mechanism and kinetics of the HER to be evaluated. Comparison of these parameters with those obtained on the polycrystalline nickel electrode in 1 M alkaline solution at 25°C indicates that an increase in activity is principally due to an increase in the real surface area. 相似文献
42.
Andrzej Małecki Jalees A.K. Tareen Jean Pierre Doumerc Louis Rabardel Jean Claude Launay 《Journal of solid state chemistry》1985,56(1):49-57
Kinetics of thermal decomposition in vacuum of Co3O4 powder as well as single crystals has been investigated. Discrepancies with the results of previous authors have been discussed. Decomposition of Co3O4 proceeds through formation of a compact layer of CoO and hence diffusion is the rate-limiting factor. The experimental curves α(t) be described for 0.05 < α < 0.85 using a modified Ginstling-Brounshtein equation: 1 ? 2α/3 ? (1 ? α)2/3 = ktn where the activation energy varies with the degree of decomposition. 相似文献
43.
Apparent molar volumes of aqueous solutions of argon and xenon have been calculated using a previously developed comprehensive equation of state for nonelectrolyte systems. The equation consists of a virial expansion truncated after the fourth virial coefficient and a closed-form term approximating higher coefficients. Mixing rules are based on the composition dependence of virial coefficients, which is known from statistical mechanics. The equation accurately represents vapor-liquid and gas-gas equilibria for the Ar+H2O and Xe+H2O systems over wide ranges of pressure and temperature using two binary parameters. With the binary parameters determined from phase equilibrium data, the equation accurately predicts apparent molar volumes V in the near-critical and far-from-critical regions. Apart from reproducing experimental V data, the equation reveals remarkable maxima of V as a function of pressure and temperature in the near-critical region. The implications of this equation with respect to the Ar–H2O potential are discussed via the second virial coefficient. 相似文献
44.
Andrzej J. Treszczanowicz George C. Benson 《The Journal of chemical thermodynamics》1977,9(12):1189-1197
Excess volumes VE measured at 298.15 K in a successive-dilution dilatometer are reported for binary mixtures of the n-alkanols C1 to C4 + n-heptane. For ethanol +, and n-butanol + n-heptane, the measurements were extended to high dilutions of alkanol. VE is positive for all of the mixtures but decreases rapidly in magnitude for increasing chain length of the n-alkanol. The results were used to estimate the excess partial molar volumes of the components. 相似文献
45.
A master equation is used to study transitions between the stable limit cycle and stable focus in the two-variable bistable system. The distribution function of the mean first passage time between these attractors and the relative dispersion of the mean first return time from the stable focus to itself as a function of the intensity of fluctuations are calculated and discussed. A coherence resonance is observed for the return time from the focus to itself. 相似文献
46.
Tautomerism of some 4,6-disubstituted pyrimidines (with the electron-donor groups such as OH, SH and NH2) is discussed with regard to their electronic absorption spectra. The spectra of different tautomeric forms of the molecules are satisfactorily interpreted by means of the Pariser—Parr—Pople type of calculations. 相似文献
47.
Andrzej W. Trochimczuk Shoji AokiKazunori Yamabe Akinori Jyo 《European Polymer Journal》2002,38(5):941-945
Four porous vinylnaphthalene/divinylnaphthalene (VN/DVN) polymers having three different nominal crosslinking degrees (60, 80 and 100 wt.%) have been synthesized using the suspension polymerization method in the presence of toluene and decane.The use of various crosslinking levels and inert diluents was aimed at changing the extent of polymeric network-diluent interactions. The resultant polymers have specific surface area in the range 450-700 m2/g depending on the DVN content. Two sets of pores were detected in all resins: one with the diameter of ≈2 nm and the second one in the range of 30-40 nm. Their sorptive properties have been studied using dilute (0.5 mmol/l) solutions of phenol and its derivatives (o-chlorophenol, 2-methylphenol, o-nitrophenol, m-nitrophenol and p-nitrophenol). It has been found that sorption, at low equilibrium concentration, follows the order: o-nitrophenol > o-chlorophenol > m-nitrophenol > o-methylphenol > p-nitrophenol > phenol. Full characteristics of the porous structure of resultant polymers was obtained by nitrogen adsorption at 77 K and their surface properties analyzed using Inverse Gas Chromatography. 相似文献
48.
Andrzej Smajdor 《Results in Mathematics》1994,26(3-4):385-389
A set-valued function F defined on a convex cone S in a real vector space X into the set n(Y) of all non-empty subsets of a real vector space Y is said to be the Jensen function iff $${1\over 2}\lbrack F(x)+F(x)\rbrack=F\lbrack{1\over 2}(x+y)\rbrack$$ for all x, y ∈ S. This note deals with iteration semigroups of Jensen set-valued functions on S. 相似文献
49.
50.
Summary It is shown that every convex set-valued function defined on a cone with a cone-basis in a real linear space with compact values in a real locally convex space has an affine selection. Similar results can be obtained for midconvex set-valued functions. 相似文献