Spelling suggestions: "subject:"ionic emobility"" "subject:"ionic dmobility""
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Studies on some fast ion conductorsNewsam, J. M. January 1980 (has links)
We report diffraction experiments on some representative Fast Ion Conductors. The structures of anhydrous stoichiometric deuterium (DAl<sub>11</sub>O<sub>17</sub>) and silver (AgAl <sub>11</sub>O<sub>17</sub>) beta aluminas have each been determined at four temperatures in the range 4 . 2K - 773K using powder neutron diffraction (PND) data. In DAl<sub>11</sub>O<sub>17</sub>, a strong D-O(5) hydroxyl linkage is maintained at all four temperatures .For AgAl<sub>11</sub>O<sub>17</sub> at 4.2K,we have observed, for the first time in metal beta aluminas, a completely ordered cation distribution. The material, which was prepared by a new route, is accurately stoichiometric. At 298K,the silver atoms have become somewhat delocalised and by 773K they are organised in a highly diffuse manner. Single crystal neutron diffraction was used to elucidate the proton distributions in ammonium beta alumina, (NH<sub>4</sub>) <sub>1.25</sub>Al<sub>11</sub>- 0<sub>17.125</sub>, and the two derivatives (NH<sub>4</sub>) <sub>0.78</sub>H<sub>0.25</sub>Al<sub>11</sub>0<sub>17</sub> and 'HA1<sub>11</sub>- 0<sub>17</sub>.In the parent compound, the positions and orientations of the two independant (NH<sup>+</sup><sub>4</sub>) species are such that all protons are involved in favourable hydrogen-bonding schemes. In formation of the first derivative, one of these sites becomes completely depopulated. Our results clarify the thermal behaviour of (NH<sub>4</sub>) <sub>1.25</sub>Al<sub>11</sub>0<sub>17.125</sub> and we propose schemes by which stoichiometric beta aluminas are formed from this precursor and the related (H<sub>3</sub>0)<sub>1+x</sub>- Al<sub>11</sub>0<sub>17.+x/2</sub>. The crystal structures of I-Ag<sub>3</sub>PO<sub>4</sub>(25°C and 375°C) , II-Ag<sub>3</sub>PO<sub>4</sub>(650°C) ,II-Na<sub>3</sub>PO<sub>4</sub> (γ) (400°C) and the solid solutions Na<sub>3(1-x)</sub>Al<sub>x</sub>PO<sub>4</sub>are described. The high-temperature forms are considered in relation to the fluorite structure and mechanisms for the ionic conduction of these phases are proposed. A single crystal X-ray diffraction study of β-Ag<sub>2</sub>SO<sub>4</sub> (25°C) reveals that it is isostructural with thenardite, V-Na <sub>2</sub>SO<sub>4</sub>.The high-temperature modifications a-Ag<sub>2</sub>SO<sub>4</sub> (490°C) and α-K<sub>2</sub>SO<sub>4</sub> (620°C) have been characterised using PND data. A PND experiment on silver (I) fluoride confirms that it adopts the rocksalt structure and we find no firm evidence for a significant population of defects.
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Gaseous ionic mobilities : interaction potential determinationsLamm, Darrell Ronald 08 1900 (has links)
No description available.
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Transport properties of gaseous ionsThackston, Michael Gordon 05 1900 (has links)
No description available.
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Ionic mobility and superplasticity in ceramics /Vilette, Anne L., January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 84-86). Also available via the Internet.
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Mobility of ionic pollutants in selected South African soils /Mwepu, Mireille K. M. January 2007 (has links)
Thesis (MScAgric)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.
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Entanglement and decoherence in a trapped-ion quantum registerKielpinski, David. January 2001 (has links) (PDF)
Thesis (Ph. D.)--University of Colorado, 2001. / Includes bibliographical references.
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The measurement and application of transport properties of ion swarms in gasesHolleman, Franklin Benton 12 1900 (has links)
No description available.
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Some aspects of ion motion in liquid helium : the study of mobility discontinuities in superfluid helium (and liquid nitrogen), and the influence of grids on the transmission of an ion beamDoake, Christopher S. M. January 1972 (has links)
We were unable to verify the existence of ion mobility discontinuities in either superfluid helium at 1 K or liquid nitrogen. The velocity-field dependence in helium was described by an increased interaction with the normal fluid, due to an increase in the roton number density close to the ion surface. The mobility results in nitrogen were interpreted as being due to liquid motion, following a theory by Kopylov. The D.C. results showed that the effect of a grid on the transmission of an ion beam could be described by a field dependent grid transmission coefficient, independent of the ion velocity. The vortex ring transmission through a grid was a complex function of vorticity being captured by the grid, the capture and escape probabilities of the bare ions by vorticity, and the onset for vorticity propagating throughout the ion cell.
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Ionic mobility and superplasticity in ceramicsVilette, Anne L. 21 July 2009 (has links)
Superplasticity and superionic conductivity (SIC), both thermally activated processes, have been independently observed in certain materials with a high diffusion coefficient in high temperature ranges. Intuitively, this observation leads one to the idea that both types of behavior may be inter-related with one another. Therefore, it is the purpose of this research to investigate, specifically, the deformation characteristics of two SIC's, Bi₂O₃ and YSZ (yttria-stabilized zirconia), and to attempt a correlation of their behavior. Compressive deformation of these two materials was conducted over a wide range of temperatures and at various strain rates in an effort to characterize the temperature and/or strain-rate dependences of any observed superplasticity. Steady-state flow stress values were utilized to calculate the strain-rate sensitivity, m, of the materials, as well as the activation energies (Q<sub>C</sub>) of superplasticity. Next, the obtained values of Q<sub>C</sub>. were compared to SIC activation energies from the literature.
Bi₂O₃ exhibited structural superplasticity within the range of test conditions utilized. However, published values of SIC activation energy were lower than experimentally derived Q<sub>C</sub> by a factor of four. Therefore, one is not able to state whether or not there is any correlation between the two behaviors. Unfortunately, YSZ exhibited brittle behavior over the entire temperature and strain-rate ranges, so the same analysis could not be performed. Furthermore, SEM micrographs showed that YSZ samples, as processed, did not possess the proper microstructure required for superplasticity. Hence, no final conclusions on YSZ can be drawn from this study. / Master of Science
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Attenuation of ionic pollutants in selected South African soilsMwepu, Mireille K. M. 03 1900 (has links)
Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2007. / Two–thirds of South Africa, including more than 280 towns and settlements are
largely dependent on groundwater for their drinking water supply and development.
However, groundwater resources in South Africa are limited both in terms of quantity
and quality, especially in the semi–arid parts of the country (Sililo et al., 2001, p. i).
Therefore, the importance of protecting groundwater resources from pollution has
been recognized.
The first objective of this research was to investigate the attenuation capacity of a
selection of soil horizons and materials representing major types of diagnostic
horizons and materials in the South African soil classification in order to validate their
chemical attenuation ratings as provisionally specified by Sililo et al. (2001, p. 4.6).
The second objective was to assess the pollutant attenuation capacity of South
African soil horizons and materials as well as describe the diagnostic value of key
chemical properties of soils for conveying information on their contaminant
transport/attenuation potential. The third objective was to investigate whether it is
possible to apply acid/base priming using H2SO4 and Ca(OH)2 to a bulk quantity of
soil in order to reduce the mobility of contaminants.
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