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201.
The solid electrolyte Ce1?xCaxO2-?x with the fluorite-type structure (Ca-doped CeO2) is a mixed conductor. Conduction occurs predominantly by migration of O2? ions via oxygen vacancies or by electrons, depending on the departure from stoichiometry. The ionic transference number σi/σi + σe was determined as a function of dopant concentration (0.07?x?0.15), temperature (400–800°C), and oxygen pressure by emf measurements with oxygen concentration cells. It is described by The entropy term S1(x) changes from 38.7k for x = 0.07 to 31.7k for x = 0.15; the enthalpy term, 5.42 eV, is independent of x and in excellent accord with semi-empirical calculations. 相似文献
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203.
Ahrens LA Aronson SH Connolly PL Gibbard BG Murtagh MJ Murtagh SJ Terada S White DH Callas JL Cutts D Diwan MV Hoftun JS Hughlock BW Lanou RE Shinkawa T Kurihara Y Amako K Kabe S Nagashima Y Suzuki Y Tatsumi S Yamaguchi Y Abe K Beier EW Doughty DC Durkin LS Heagy SM Hurley M Mann AK Newcomer FM Williams HH York T Hedin D Marx MD Stern E 《Physical review D: Particles and fields》1990,41(11):3297-3316
204.
Mike Hurley 《Journal of Dynamics and Differential Equations》1995,7(3):437-456
This paper is a study of chain recurrence and attractors for maps and semiflows on arbitrary metric spaces. The main results are as follows. (i) C. Conley's characterization of chain recurrence in terms of attractors holds for maps and semiflows on any metric space. (ii) An alternative definition of chain recurrence for semiflows is given and is shown to be equivalent to the usual definition. The alternative definition uses chains formed of orbit segments whose lengths are at least 1, while in the usual definition these lengths are required to be arbitrarily long. (iii) The chain recurrent set of a continuous semiflow is the same as the chain recurrent set of its time-one map. (iv) Conditions on a real-valued function are given that ensure that the semiflow generated by its gradient has only equilibria in its chain recurrent set. An example is given (onR
3) showing that a gradient flow may have nonequilibrium chain recurrent points if these conditions are violated. 相似文献
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208.
Smog chamber/FTIR techniques were used to measure k(Cl + HCF2OCF2OCF2‐CF2OCF2H) = k(Cl + HCF2O(CF2O)n(CF2CF2O)mCF2H) = (5.0 ± 1.4) × 10?17 cm3 molecule?1 s?1 in 700 Torr of N2/O2 diluent at 296 ± 1 K. The Cl‐initiated atmospheric oxidation of HCF2OCF2OCF2CF2OCF2H and the sample of HCF2O(CF2O)n(CF2CF2O)mCF2H used in this work gave COF2 in molar yields of (476 ± 36)% and (859 ± 63)%, respectively, with no other observable carbon containing products (i.e., essentially complete conversion of both hydrofluoropolyethers into COF2). The results are discussed with respect to the atmospheric chemistry and environmental impact of hydrofluoropolyethers of the general formula HCF2O(CF2O)n(CF2CF2O)mCF2H. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 819–825, 2008 相似文献
209.
Siracusa L Hurley FM Dresen S Lawless LJ Pérez-Payán MN Davis AP 《Organic letters》2002,4(26):4639-4642
[reaction: see text] Cholic acid has been elaborated into three regioisomeric bis-carbamoylureas, which have been investigated as enantioselective receptors for N-acetyl phenylalanine. L/D selectivities, peaking at 5:1, have been determined by a sensitive and rapid MS-based extraction method that should be generalizable to related systems. 相似文献
210.
Summary We study the action of a continuous mapf on a locally connected metric space, with an emphasis on the action induced byf on the space of connected components of an attractorA or a stable setY off. The main result for attractors is that, ifA is an attractor in the sense of C. Conley, thenf permutes the components ofA and that the permutation is cyclic if and only if the attractor is indecomposable. This is related to similar results obtained recently by Buescu and Stewart. In the case of an indecomposable stable invariant setY we show that either the action off on the components ofY is as described above for the action on the attractor, or elseY has infinitely many components, the action off on them is a generalized adding machine, so that there are no periodic points inY. Results along these lines are due to Buescu and Stewart and to Melbourne, Dellnitz and Golubitsky. 相似文献