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61.
A volume step method measuring the pressure and the adsorbent temperature of an adsorbent-adsorbate system has been developped. It is shown that this method allows the determination of all the relevant parameters of an adsorption process, kinetic as well as thermodynamic in case of Linear Driving Force mass transfer. The method for determining the parameters can be extended to the case of diffusive mass transfer if the mass transfer kinetics is faster than the heat transfer kinetics. An example is given, showing the determination of the diffusion coefficient of carbon dioxide in NaX zeolite pellets and the change of the diffusion coefficient and of the isosteric heat of adsorption when the adsorbent is not fully dehydrated. 相似文献
62.
63.
Didier Bresch David Gérard-Varet Emmanuel Grenier 《Archive for Rational Mechanics and Analysis》2006,182(3):387-413
In this paper, we justify mathematically the derivation of the planetary geostrophic equations (PGE) from the hydrostatic
Boussinesq equations with Coriolis force, usually named the primitive equations (PE). The planetary geostrophic equations,
which are a classical model of thermohaline circulation, are obtained from the primitive equations as the Froude number Fr,
the Rossby number , and the Burger number Bu go to 0. These numbers are supposed to satisfy
and which is relevant to the thermohaline planetary dynamics. The analysis performed here does not follow the same lines as previous
asymptotic studies on rotating fluids. It involves a singular operator which is not skew symmetric, and prevents classical
energy estimates. To handle such operator requires to put the primitive equations under normal form, together with an appropriate use of the viscous terms. 相似文献
64.
A new series of soluble C60 derivatives for organic electronic application has been synthesized by ethynylation reaction using different electron-donating and electron-withdrawing groups of varying length. 相似文献
65.
Antonin?Chambolle Christopher?J.?LarsenEmail author 《Calculus of Variations and Partial Differential Equations》2003,18(1):77-94
We study the regularizing effect of perimeter penalties for a problem of optimal compliance in two dimensions. In particular, we consider minimizers of
where
The sets
,
, and the force f are given. We show that if we consider only scalar valued u and constant
, or if we consider the elastic energy
, then
is
away from where
is pinned. In the scalar case, we also show that, for any
of class
,
is
. The proofs rely on a notion of weak outward curvature of
, which we can bound without considering properties of the minimizing fields, together with a bootstrap argument.Received: 5 March 2002, Accepted: 3 September 2002, Published online: 17 December 2002 相似文献
66.
Daniel Grenier Robert E. Prud'Homme Alain Leborgne Nicolas Spassky 《Journal of polymer science. Part A, Polymer chemistry》1981,19(7):1781-1793
S(?) and R(+) enantiomers of α-methyl-α-ethyl-β-propiolactone (MEEPL) were prepared in an eight-step synthesis with respective optical purities of 99 and 97% determined by 1H-NMR (250 MHz) spectroscopy. Polymers (PMEPL) of different enatiomeric compositions were prepared with an anionic-type initiator. Substantial differences in physical properties were observed between the racemic and optically pure polymers; for example, the melting point of the latter is 42°C higher than that of the former. Chiroptical properties of PMEPLs are reported. The 13C-NMR (100.62 MHz) spectra of the polymers indicated that the distribution of configurational units in the macromolecular chain is random. 相似文献
67.
María Vallet-Regí José González-Calbet Miguel A. Alario-Franco Jean-Claude Grenier Paul Hagenmuller 《Journal of solid state chemistry》1984,55(3):251-261
An electron microscopy and diffraction study of several samples of the system shows these solids to be formed by the disordered intergrowth of two out of three of the ordered terms corresponding to , and x = 1 (i.e., LaFeO3, Ca2LaFe3O8, and Ca2Fe2O5). The relative amounts of the intergrowing individuals vary with x and may extend down to unit cell thickness; i.e., to the level of isolated extended defects. 相似文献
68.
Measurements have been performed on the influence of a small amount of water on adsorption properties of alkanes (C3 to C6) and olefins (C3 and C4) in NaX zeolite. Adsorption capacity and heat of adsorption have been measured by a Volume Step method. Kinetics has been measured by Thermal Frequency Response method and the results have been compared with the results obtained by PFG-NMR.It has been found that water reduces the adsorption capacity especially at low adsorbate concentration. The heat of adsorption is slightly reduced by water. The kinetics of alkanes is always reduced by the adsorbed water. On the contrary, the diffusion kinetics of olefins is improved or remains unchanged, depending of the sorbat concentration. 相似文献
69.
70.
The different conformations of the methyl groups for a series of saturated cyclic and linear hydrocarbons were analysed. From these results we were able to identify the different interactions H/H, H/Me, Me/Me and calculate the chemical shifts of the methyl group for a series of hydroxylated stereoisomers. 相似文献