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1.
The impedance spectra of Pb5Ge3O11 single crystals are measured in the frequency range from 5 Hz to 13 MHz at temperatures of 600 to 800 K in dry air and in
a dry or wet nitrogen gas. It is found that the temperature and the gas composition significantly affect the electrical properties
of the compound. The data obtained are used to discuss the origin of crystal lattice defects and their influence on charge
transfer. It is concluded that the conduction is mixed in character (p-type electronic and ionic due to oxygen ions). The proton conduction is shown experimentally to be feasible. The possible
mechanisms of proton transport in Pb5Ge3O11 are discussed. 相似文献
2.
The self-diffusion of benzene, toluene, and ethylbenzene in polystyrene have been analyzed using the Vrentas/Duda free-volume diffusion model. Diffusion coefficient predictions suggest an exponential concentration dependence of the activation energy required to overcome attractive forces, E. Without the use of any diffusion data approximating E as zero over the entire concentration range yields self-diffusion coefficient predictions which are in good agreement with experimental data. © 1992 John Wiley & Sons, Inc. 相似文献
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Abramowicz H Belusevic R Blondel A Blümer H Böckmann P Brummel HD Buchholz P Burkhardt H Debu P Duda J Dydak F Falkenburg B Fiedler M Geiges R Geweniger C Grant AL Guyot C Hagelberg R Hepp V Hughes EW Kampschulte B Keilwerth H Kleinknecht K Knobloch J Krasny M Królikowski J Kurz N Lipniacka A Merlo J Müller E Para A Perez P Perrier F Pollman D Ranjard F Renk B Schuller J Taureg H Tittel K Turlay R Vallage B Wachsmuth H Wotschack J 《Physical review letters》1986,57(3):298-301
5.
Rudovsky J Hermann P Botta M Aime S Lukes I 《Chemical communications (Cambridge, England)》2005,(18):2390-2392
A marked increase of relaxivity has been observed upon rigidifying the internal frame of Gd-containing PAMAM dendrimers: the effect has been attained by either protonation of the dendrimer or by forming supramolecular adducts with cationic polyaminoacids. 相似文献
6.
Yan-Cong Chen Yan Meng Yan-Jie Dong Xiao-Wei Song Guo-Zhang Huang Chuan-Lei Zhang Zhao-Ping Ni Jakub Navaík Ondej Malina Radek Zboil Ming-Liang Tong 《Chemical science》2020,11(12):3281
Among responsive multistable materials, spin crossover (SCO) systems are of particular interest for stabilizing multiple spin states with various stimulus inputs and physical outputs. Here, in a 2D Hofmann-type coordination polymer, [Fe(isoq)2{Au(CN)2}2] (isoq = isoquinoline), a medium-temperature annealing process is introduced after light/temperature stimulation, which accesses the hidden multistability of the spin state. With the combined effort of magnetic, crystallographic and Mössbauer spectral investigation, these distinct spin states are identified and the light- and temperature-assisted transition pathways are clarified. Such excitation-relaxation and trapping-relaxation joint mechanisms, as ingenious interplays between the kinetic and thermodynamic effects, uncover hidden possibilities for the discovery of multistable materials and the development of multistate intelligent devices.Two new two-stage manipulation protocols, namely light- and temperature-assisted spin state annealing (LASSA/TASSA), are applied to a spin crossover coordination polymer, [Fe(isoq)2{Au(CN)2}2], revealing the hidden multistability of spin states. 相似文献
7.
Jakub Wojciechowski Henryk Krawczyk Marcin
liwiski Karolina Kafarska Wojciech M. Wolf 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o280-o282
The title compound, C14H20O2, adopts a conformation in which the δ‐valerolactone and cyclohexane rings are almost coplanar with one another. The γ‐methyl substituent occupies an axial position with respect to the cyclohexane ring. The δ‐valerolactone moiety adopts an envelope arrangement, while the cyclohexane ring exists in a chair conformation. 相似文献
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Jakub Kołacz Henry G. Gotjen Robel Y. Bekele Jason D. Myers Jesse A. Frantz Michael Ziemkiewicz 《Liquid crystals》2020,47(4):531-539
ABSTRACTIn a planar dielectric waveguide, weak confinement of a propagating mode in a high index core leads to a measurable evanescent interaction with the cladding. In this work, we study the effect of a reorientable anisotropic cladding on the behaviour of Transverse Electric (TE) and Transverse Magnetic (TM) mode polarisations using a liquid crystal (LC)-clad waveguide architecture. The polarised evanescent field of a guided mode interacts with a voltage-tunable birefringent LC cladding to deflect an out-coupled beam. Experimental measurements are coupled with a theoretical framework and show good consistency with simulation results. We isolate the effect of mode confinement by changing the thickness of the high index core. Interactions between the LC index ellipsoid and the mode polarisation are probed by changing the initial alignment of the LC. Finally, we examine the difference in deflection between TE and TM modes, which incorporates both a change in mode confinement and a difference in LC index components. 相似文献