Cell, unit planar density

P. Yuan and S.-F. Liu. Numerical analysis of temperature and current density distribution of a planar solid oxide fuel cell unit with nonuniform inlet flow. Num. Heat Transfer, 51 941-957, 2007. 

Studies on other high-temperature superconductors Positron annihilation measurements across Tc, coupled with the calculations of PDD have been carried out in a variety of hole-doped superconductors that include YBa2Cu40g [48], Bi-Sr-Ca-Cu-0 [49], and Tl-Ba-Ca-Cu-0 [50, 51] systems. We will not labor with the details here, except to state that a variety of temperature dependencies are seen and these can be rationalized when the results are analysed in terms of positron density distribution and the electron-positron overlap function [39]. These calculations show that the positron s sensitivity to the superconducting transition arises primarily from the ability to probe the Cu-O network in the Cu-0 layer. The different temperature dependencies of lifetime, i.e., both the increase and decrease, can be understood in terms of a model of local electron transfer from the planar oxygen atom to the apical oxygen atom, after taking into account the correct positron density distribution within the unit cell of the cuprate superconductor. 

This form has been characterized by Chatani et al. from WAXD data from fibers originally in the planar zigzag polymorph and then exposed to benzene, toluene, or p-xylene vapours below 50°C for several days. A triclinic cell was determined containing six monomer units and with a crystallographic density of 0.939 g/cm. The chain conformation is —TTgG2T2G2)— which may be considered as intermediate between the original —(IT)— conformation and the hehcal conformation... 

In Figure 5.37 (a) the ideal case of the planar projection of the electronic density of contour at the ideal unit cell level (e = 0) is exposed. A good resolution of the electronic distribution is noted, so illustrating the electronic density around the atomic scattering centers. 

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