Roughness developer concentration effect

Figure 6.21 shows the AC impedance spectra for the cathodic ORR of the cell electrodes prepared using the conventional method and the sputtering method. It can be seen that the spectra of electrodes 2 and 3 do not indicate mass transport limitation at either potentials. For electrode 1, a low-frequency arc develops, due to polarization caused by water transport in the membrane. It is also observable that the high-frequency arc for the porous electrode is significantly depressed from the typical semicircular shape. Nevertheless, the real-axis component of the arc roughly represents the effective charge-transfer resistance, which is a function of both the real surface area of the electrode and the surface concentrations of the species involved in the electrode reaction. 

Figure 5. Effect of developer concentration and dose on top surface roughness of Shipley SAL 605. The developer MF-312, a tetramethylanimonium hydroxide developer, was diluted with water to 0.27N, 0.24N, and 0.2IN concentrations.

The key physics of our model (see Eqs. (9) and (10)) is contained in the nonlocal diffusion kernels which occur after integrating over the atomic processes which produce step fluctuations. We have calculated these kernels for a variety of physically interesting cases (see Appendix C) and have related the parameters in those kernels to atomic energy barriers (see Appendix B). The model used here is close in spirit to the work of Pimpinelli et al. [13], who developed a scaling analysis based on diffusion ideas. The theory of Einstein and co-workers and Bales and Zangwill is based on an equihbrated gas of atoms on each terrace. The concentration of this gas of atoms obeys Laplace s equation just as our probability P does. To make complete contact between the two methods however, we would need to treat the effect of a gas of atoms on the diffusion probabilities we have studied. Actually there are two effects that could be included. (1) The effect of step roughness on P(J) - we checked this numerically and foimd it to be quite small and (2) The effect of atom interactions on the terrace - This leads to the tracer diffusion problem. It is known that in the presence of interactions, Laplace s equation still holds for the calculation of P(t), but there is a concentration... 

Anhydrous perchloric acid is not sold commercially, Aqueous solutions of perchloric acid are sold at low concentrations foi analytical standard applications and at concentrations up to 70%. The price for 70% perchloric acid varies and starts at 2.70/kg, depending on the quantity and level of impurities. The U.S. domestic capacity of ammonium perchlorate is roughly estimated at 31,250 t/yr. The actual production vanes, based on the requirements for solid propellants. Environmental effects of the decomposition products, which result from using solid rocket motors based on ammonium perchlorate-containing propellants, are expected to keep increasing public pressure until consumption is reduced and alternatives are developed. Approximately 450 t/yr of NH+ClCXt-equivalent cell liquor is sold to produce magnesium and lithium perchlorate for use in the production of batteries. 

B.K. Aral and D.M. Kalyon, Effects of Temperature and Surface Roughness on Time-Dependent Development of Wall Slip in Steady Torsional Flow of Concentrated Suspensions, J. Rheol., 38(4) 957-972 (1994). 

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