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181.
Woo-Jin Lee Su-Il Pyun Tae-Hyun Yang Joong-Do Kim Young-Ho Baek Han-Gyu Kim 《Journal of Solid State Electrochemistry》1997,1(2):120-125
Hydrogen transport through a Pd-Ni alloy electrodeposited on a Pd substrate (Pd-Ni/Pd bilayer symmetric electrode) has been
investigated using cyclic voltammetry and a.c. impedance spectroscopy combined with the electrochemical hydrogen permeation
method. The permeation build-up current transients and the measured impedance spectra were analyzed using the time-lag method
for the bilayer electrode and a complex non-linear least squares data-fitting method based upon the derived Faradaic admittance
for the hydrogen absorption into and diffusion through the bilayer electrode under the permeable boundary condition, respectively.
The value of the hydrogen diffusivity in the Pd-Ni layer was lower than that in the Pd layer. Furthermore, the values of the
charge transfer resistance and equilibrium absorption constant for the Pd-Ni/Pd bilayer electrode were higher than those for
the Pd single layer electrode. From the experimental results, the role of the thin Ni(OH)2 film formed on the Pd-Ni layer surface in the hydrogen transport through the Pd-Ni/Pd bilayer electrode is discussed in terms
of its passivating effect and extremely large hydrogen solubility.
Received: 22 January 1997 / Accepted: 15 April 1997 相似文献
182.
L. P. Kozeeva M. Yu. Kameneva N. V. Podberezskaya I. G. Vasilieva N. V. Kuratieva D. Yu. Naumov V. A. Nadolinnyi V. E. Fedorov 《Journal of Structural Chemistry》2004,45(2):253-261
Cooling a melt of a Bi–Sr–Ca–Cu–O system (Bi:Sr:Ca:Cu = 4:3:3:4 or 2:2:2:4) from 1000°C-1050°C yielded crystals of a new red-colored nonsuperconducting phase, accompanying the superconducting 2212 and 2201 phases. Based on the EPR spectra, it was concluded that copper is univalent in this compound. The new phase has a composition Bi2.2Sr1.6Ca1.3Cu2Ox. The X-ray diffraction pattern has been indexed, and the unit cell parameters of the phase have been determined: space group P2/m, a = 12.93, b = 4.55, c = 10.94 ; = 102.72°. 相似文献
183.
O. Yu. Slabko N. V. Ageenko D. V Kuklev V. A. Kaminski 《Chemistry of Heterocyclic Compounds》2002,38(3):354-358
Oxidative coupling of derivatives of 4a,9-diaza-1,2,4a,9a-tetrahydro-9H-fluorene with 2-ethyl-, 2,2-dimethyl-, and 2-hydroxymethyl-2-methylaminoethanol in the presence of MnO2 led to the selective formation of the corresponding mono- and di(hydroxymethyl)quinonediimines, subsequent cyclization of which gave the products of 6,7-annelation. Coupling with 2,2-di(hydroxymethyl)aminoethanol gave the annelation products directly. 相似文献
184.
Global Existence of Solutions and Lower Bound Estimate of Blow-Up Time for the Keller-Segel Chemotaxis Model北大核心CSCD 下载免费PDF全文
A macroscopic nonlinear Keller-Segel model for chemotactic cell migration was considered, where the existence region of the model is a bounded convex one on Ω ⊂ RN(N≥2). The global existence of the solution on Ω ⊂ R3 was obtained by means of the energy estimate method. The lower bound of the blow-up time was proved for N = 3 and N = 2. © 2022 Editorial Office of Applied Mathematics and Mechanics. All rights reserved. 相似文献
185.
186.
On bandwidth sums of graphs 总被引:1,自引:0,他引:1
ONBANDWIDTHSUMSOFGRAPHSYAOBING(姚兵);WANGJIANFANG(王建方)(DepartmentofMathematics,NorihwesteternNormalUniversity,Lanzhou730070,Chi... 相似文献
187.
We prove two new upper bounds on the size of binary codes with a minimum distance of three, namelyA(10, 3)76 andA(11, 3)152. 相似文献
188.
We investigate the influence of long range interactions on the relaxation behaviour of a lattice model with an on-site potential of
4-type and infinite range harmonic interactions. For finite number of particlesN, it is shown that the autocorrelation functions <E
n(t)E
n
> of the fluctuations of the one-particle energiesE
n(t) decays exponentially. The corresponding relaxation time is proportional toN and is given by (T, N) =N0(T). The temperature dependent time scale 0 can explicitly be related to the dynamics of a one-particle correlator of the noninteracting system. The results are derived using Mori-Zwanzig projection formalism. The corresponding memory kernel is calculated within a mode coupling approximation and by a perturbative approach. Both results agree in leading order in 1/N. It is speculated that any interaction of range generates a timescale . 相似文献
189.
The present paper studies the properties of Hubbard-like models in high spatial dimensionsD. In a first par the limit of infinite dimension and its main features-i.e.i) the mapping onto a generalized atomic model with an additional auxiliary field andii) the validity of the local approximation for the self-energy-are worked out in a systematic (1/D)-expansion. Since the hopping matrix elements have to be properly scaled with the dimensionD, the (1/D)-expansion is also an expansion in the hopping amplitude. Thus for small hopping theD-limit may serve as a proper approximation for finite-dimensional systems. The second part of the paper adopts the hybridisation-perturbation theory of the single impurity Anderson model in order to construct a perturbation theory for the auxiliary field of the generalized atom which can also be interpreted as an expansion in the hopping amplitude. The non-crossing approximation (NCA) is used to study the antiferromagnetic phase transtion of theD-Hubbard model in the case of half filling: the critical temperature, the antiferromagnetic order parameter and the free energy of the lattice system are calculated. The NCA-results are in quite good agreement with recent results from the imaginary-time discretisation method. 相似文献
190.
Ferenc Mó ricz Ká roly Tandori 《Proceedings of the American Mathematical Society》1996,124(3):877-885
We study the a.e. convergence of orthogonal series defined over a general measure space. We give sufficient conditions which contain the Menshov-Rademacher theorem as an endpoint case. These conditions turn out to be necessary in the particular case where the measure space is the unit interval and the moduli of the coefficients form a nonincreasing sequence. We also prove a new version of the Menshov-Rademacher inequality.