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991.
Electrochromic effects are observed by employing a single mixed ionic and electronic conducting layer in-between two transparent
electronic leads. Besides the simplicity of the arrangement, the advantage is the displacement of ions only within one phase
rather than across phase boundaries as required by conventional devices.
The applied voltage controls the compositions at the two interfaces according to Nernst's law independent of ions being majority
or minority charge carriers. Appropriate materials are intrinsic conductors in the unpolarized transparent state which become
n-type and p-type conducting at the negative and positive electrode side, respectively. Several materials have been investigated,
such as lithiated tungsten oxide and lithium/tantalum co-doped tungsten oxide.
Paper presented at the 1st Euroconference on Solid State Ionics, Zakynthos, Greece, 11–18 September 1994. 相似文献
992.
George Fytas Thomas Dorfmuller Benjamin Chu 《Journal of Polymer Science.Polymer Physics》1984,22(8):1471-1481
We report polarized photon correlation measurements of bulk poly(phenylmethyl siloxane) (PPMS) with a molecular weight of about 2500 at different pressures from 1 to 1750 bar and temperatures between 269 and 308 K. In the Frequency range accessible by present-day digital correlators, the time correlation function can measure a slow q2-dependent diffusional process due to local concentration fluctuations and a fast α-mode structural relaxation process. The mean characteristic times of the two processes approach each other at low temperatures and high pressures, in contrast to the behavior of the α- and β-relaxation times. We should be cautious in relating the mean characteristic times for the structural relaxation process obtained by different experimental techniques, such as Brillouin scattering and photon correlation spectroscopy, because of the differnces in the probe emphasis and the extremely broad frequency distribution of such relaxation processes. 相似文献
993.
994.
995.
Patrice de Meester Shirley S. C. Chu Misa V. Jovanovic Edward R. Biehl 《Journal of heterocyclic chemistry》1986,23(4):1131-1133
The X-ray crystal structure of 5-methyl-5,10-dihydrophenarsazine, C13H12NAs, has been determined. The crystals are orthorhombic, space group P212121, a = 8.511(4), b = 5.690(1), c = 23.535(9) Å, V = 1139.7(1.0)A3, and Z = 4. Least-squares refinement converged to R = 0.049 and Rw = 0.045. The central ring is in a boat conformation and the 5-methyl group is in the axial position with respect to the central ring. The folding angle between the planes of the two benzo rings is 154.1(4)°. 相似文献
996.
It is shown that many of the existing index profiling methods for optical fibre and preform are related to one another through the deflection function from which the index profile is reconstructed. These methods are classified into direct deflection function measurement, integral (or phase) measurement, and differential (or intensity) measurement. The deflection function from the integral method is obtained by measuring the phase distribution of the exit rays followed by numerical differentiation. Thus the reconstructed index profile has Gaussian noise. The deflection function from the differential method is obtained by measuring the light intensity distribution followed by a numerical integration. This process enhances low frequency noise but suppresses high frequency noise. The noise from direct method behaves in the similar manner as in the differential method except that it is less pronounced. Studies of the choice of methods for profiling of preform, multimode fibre and single mode fibre are also given. 相似文献
997.
998.
X. Zhang S.S. Chu J.R. Ho C.P. Grigoropoulos 《Applied Physics A: Materials Science & Processing》1997,64(6):545-552
Received: 21 June 1996/Accepted: 9 December 1996 相似文献
999.
1000.
The transport properties of ionic conductors such as α-AgI and Li0.23La0.69Fe0.3Ti0.7O3 and of electronically conducting semiconductors such as α-Ag2S and AgxWO3 as a result of the application of voltages smaller than the decomposition voltage by two ionically blocking electrodes were
investigated. The mobile ionic as well as the mobile electronic species are shifted from one electrode side to the other one.
The change in the stoichiometric composition within the sample as a result of this transport process causes the formation
of local inhomogeneities leading to changes in the electrical and optical properties. The experimental results also show that
Nernst's law is not only valid for ionic conductors but also for semiconductors as well when a steady state is reached for
ionically blocking electrodes.
Paper presented at the 4th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997 相似文献