Observed penetration depth

An observed penetration depth rewritten as 8=8h+(8-Sh) corresponds to the addition of a vertical displacement 5-6h at constant radius of contact ou, that is to say to the addition of the vertical movement of a flat rigid axi-symetrical punch inducmg a strong divergence of the normal stresses on the border of the contact area. 

Due to the low penetration depth of X-rays in heavy element samples, XRD patterns are not always significant for the structure of the bulk. In analogy to observations made on rare earth metal foils, fee phases observed occasionally after heating and interpreted as high temperature phases of the actinide metals, might be the product of a reaction between the metal surface and residual gas leading, e.g. to hydride etc. 

The fact that ATR-IR spectroscopy uses an evanescent field and therefore probes only the volume very close to the IRE has important consequences for its application in heterogeneous catalysis, in investigations of films of powder catalysts. The catalyst particle size and packing affect the size of the detectable signals from the catalyst and bulk phase. Furthermore, if the catalyst layer is much thicker than the penetration depth of the evanescent field, diffusion of reactants and products may influence the observed signals. In fast reactions, gradients may exist within the catalyst layer, and ATR probes only the slice closest to the IRE. 

As it is clear that the higher the exchange current density, the lower the penetration depth and catalyst utilization, it is evident that for the more active platinum metal catalysts, an improvement of catalyst performance by using highly porous coatings is neither expected nor observed, as the normal coating roughness of 1 /im already corresponds to the penetration depth in a nanopore (82). 

Four replicate columns were run, and all produced the same type of elution curve. Lyophilized samples of another aliquot of the same soil used in the columns yielded soil water with a tritium concentration the same as that in the first aliquot drawn from the column. The first aliquot was equivalent to 1 inch of rain on the column and represents about one-third of the free water in the original soil material in the column. Zimmerman (13) reported a similar phenomenon when he used tritiated water to trace pulses of rainwater in soil systems. He found a relatively discrete front associated with the tritium injection after rainfall had occurred and eluted the tritium pulse into the soil profile. The frontal movement of high specific activity tritiated water from the surface layers in ejecta strata Sedan accounts for the peak tritium concentrations observed at depths just below the maximum penetration of rainfall. 

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