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Sunanda Banerjee Rohini M Godbole Sreerup Raychaudhuri Ben Allanach Sunanda Banerjee Satyaki Bhattacharyya Debajyoti Choudhury Siba Prasad Das Anindya Datta Rohini M Godbole Monoranjan Guchait Sabine Kraml Gobinda Majumdar David Miller Margarete Mühlleitner Nobuchika Okada Maxim Perelstein Santosh K Rai Sreerup Raychaudhuri Saurabh D Rindani DP Roy K Sridhar Rishikesh Vaidya D Zeppenfeld 《Pramana》2006,67(4):617-637
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology
(WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these
problems by the subgroups formed during the workshop is included in this report. 相似文献
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In this work we address the optimization of mixed conductivity in fluorite compounds based on zirconia. Phase relations of the new systems YbO1.5-NbO2.5-ZrO2, and CaO-NbO2.5-ZrO2 are presented. The limit of the cubic defect fluorite phase in YbO1.5-NbO2.5-ZrO2 closely resembles that of the system YO1.5-NbO2.5-ZrO2, whilst in CaO-NbO2.5-ZrO2 is narrow extending to include composition Ca0.255Nb0.15Zr0.595O1.82 at 1500°C. The influence of dopant ion size, charge and composition on ionic conduction is assessed and parallels are drawn with the systems YO1.5-NbO2.5-ZrO2 and YO1.5-TiO2-ZrO2. Comparison of these results with published data on the Ti containing systems CaO-TiO2-ZrO2, GdO1.5-TiO2-ZrO2 shows that the highest mixed conducting compositions can only be offered in the system YO1.5-TiO2-ZrO2 out of all the systems here studied. 相似文献
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Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献
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The solid solubilities of potential B-site dopants in LaNb1-xMxO4−δ, materials, M=Ga, Ge, Si, Al, B, P, Zr or Ti, have been investigated in the search for possible novel proton conductors. In general, the solubility levels of these cations were found to be very low (x≤0.03). At the maximum value x=0.03, only compositions containing Ti, Ge, Ga and Si appeared pure at the limit of resolution of XRD. The literature phase diagram, La2O3-Nb2O5-ZrO2, has been re-analysed for compositions of low Zr-content around the composition LaNbO4. The electrical properties of phase pure Ti-doped compositions have been studied. Higher bulk and total conductivities were observed in wet than dry conditions, suggesting a significant protonic contribution to total conductivity. In wet conditions, the activation energy for bulk conductivity of LaNb0.98Ti0.02O4-δ was found to be much higher than that of an A-site, Sr-doped material, Sr0.02La0.98NbO4-δ, of similar acceptor dopant concentration. The Sr-doped composition offered higher conductivities than the Ti-doped composition up to approximately 900°C. 相似文献
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Co-sintering of Cu-CGO cermet anodes on CGO (Ce0.8Gd0.2O2−δ) electrolyte was conducted at low temperature (1000 °C) by introducing small amounts (2 mol.%) of CuO sintering aid to the
electrolytic CGO. The Cu-CGO anodes with Cu contents from 20–50 vol.% were prepared by combustion synthesis followed by sintering
and reduction. Symmetrical anode/electrolyte/anode assemblies of Cu-GCO/CGO/Cu-CGO were fabricated by manually depositing
the anode combustion powder on a green substrate of the 2 mol% CuO-containing CGO, followed by co-pressing and co-sintering
of the assembly at 1000 °C. The low-temperature sintered CGO is submicron with 95–99% relative density. CuO addition has no
significant effect on either the total or ionic conductivity of the electrolyte, but p-type conduction in the temperature
range, 900–1200 °C, is 25 times higher than that of undoped CGO. Oxygen-ion transference numbers of the Cu-containing CGO
lie in the range 0.89–0.99, as determined by the modified e.m.f. technique under an oxygen/air potential gradient. The activation
energy for ionic conduction, 83 kJmol−1, is significantly lower than that for p-type electronic transport, 140 kJmol−1.
Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15 – 21, 2002. 相似文献
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Ac impedance spectroscopy and neutron powder diffraction have been used to study the high temperature behaviour of defective
fluorite solid electrolytes. In yttria-stabilised zirconia with an yttrium content of 15 mol% YO1.5 there is a marked change in conductivity behaviour at around 650 °C, with a decrease in activation energy of 0.15 eV. Structural
studies confirm that this is due to a change in the bulk of the sample with the disappearance of diffuse scattering peaks
and marked changes in the behaviour of the isotropic temperature factors at the same temperature. These results indicate that
the change in activation energy of yttria-stabilised zirconia at 650 °C is due to an order-disorder transition involving local
defect clusters. In studies of zirconia co-doped with yttrium and niobium, activation energy for conduction is found to rapidly
increase with the concentration of the trivalent yttrium Saturation doping is reached at about 20–30 % of yttrium and activation
energy only increases slightly with doping. Introduction of pentavalent niobium at this level of doping serves to decrease
activation energy, although it also decreases conductivity slightly. The low and high temperature activation energies converge
as the saturation regime is approached. These observations seem to suggest that ordering of defect clusters into microdomains
increases activation energy for ionic motion. At low defect concentrations and high temperatures, this local ordering breaks
down and the activation energy for conduction decreases.
Paper presented at the 2nd Euroconference on Solid State Ionics, Funchal, Madeira, Portugal, Sept. 10–16, 1995 相似文献
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J.F. Monteiro A.A.L. Ferreira I. Antunes D.P. Fagg J.R. Frade 《Journal of solid state chemistry》2012
Chemical potential phase stability diagrams were calculated from relevant thermodynamic properties and used to predict the thermodynamic driving force under prospective conditions of room temperature mechanosynthesis. One analysed the dependence of chemical potential diagrams on temperature and partial pressure of evolving gases such as oxygen or carbon dioxide, as expected on using strontium peroxide or strontium carbonate as precursor reactants for the alkali earth component. Thermodynamic calculations were also obtained for changes in titania precursor reactants, including thermodynamic predictions for reactivity of strontium carbonate with amorphous titania. Experimental evidence showed that strontium titanate can be obtained by mechanosynthesis of strontium carbonate+anatase mixtures, due to previous amorphization under high energy milling. Ability to perform mechanosynthesis with less energetic milling depends on the suitable choice of alternative precursor reactants, which meet the thermodynamic requirements without previous amorphization; this was demonstrated by mechanosynthesis from anatase+strontium peroxide mixtures. 相似文献
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The scattering of incident plane elastic waves by a varietyof different defects that lie upon a fluid-solid interface isconsidered here using matched asymptotic expansions. The expansionscheme is developed in terms of a parameter , the ratio of typicaldefect length scale to a typical wavelength of the incidentfield, taken to be small. Three different canonical situations occur and these are illustratedvia three specific examples treated here: a rigid strut, anedge crack, and a rigid strip. In each case the leading-ordermatching is performed to identify the leading-order contributionof the defect to the acoustic field in the far field. In particular,each defect is identified with a source of dipole response ininterfacial stress of displacement. It is shown in the limit as s<<s1 that in the inner problemsthe fluid and solid pieces uncouple in a particularly convenientmanner allowing analytical solutions to be deduced. These arethen matched with appropriate outer solutions. 相似文献