Matrix effect implantation

SIMS 0.001-0.1 1 03-1 o6 ion implanted standards +/+ surface analysis huge matrix effect, interferences... 

Galuska and Morrison [45] showed that the secondary ion yields and sputtering yields of AlxGa- xAs matrices are linearly dependent on the sample composition. Relative ion yield, and relative sputtering yield calibration lines are used to determine the concentration of 8 implanted into a multilayer-multimatrix specimen. In other work [46], they applied a point-by-point matrix effect calibration procedure to a variety of AlxGa-) xAs multilayer-multimatrix specimens grown by MBE. 

Dose levels of implanted species can be well controlled to ensure that peak concentrations remain below 1 atomic %. As covered in Section 3.3.2, additional matrix effects can be introduced if the concentration lies above this limit particularly if chemically reactive elements are introduced... 

While the effective life of Norplant I is at least five years, most of the users have the implants removed at an earlier time. Norplant II was developed to have a shorter life-span, and is composed of only two rods. Levonorgestrel is dispersed in the silastic matrix which is then inserted into a thin silastic tubing. This product has an effective life-span of two to three years (36). Because it is composed of only two rods, Norplant II also is easier to implant and remove. 

Recently, water-soluble protein fractions, isolated from extracts of bone matrix, were incorporated into a collagen matrix and shown to induce bone (67,68) and cartilage formation both in vitro and in vivo (69,70). In the latter studies, in the absence of the collajgen delivery system, the proteins were incapable of inducing cartilage formation in vivo when implanted intramuscularly into mice. The success of this approach appears to depend on delivering the active agents at an effective dose over an extended time period. 

Ion implantation is often recommended as an efficient tool to enhance electrocatalysis either by disrupting the surface structure of the catalyst or by placing active atoms on an inactive (or less active) matrix. The latter possibility (which links this section with Section 3.3 devoted to adatoms) offers also a way to the use of extremely small amounts of active but expensive materials. In order to investigate the effect of surface damages, self-implantation or ion beam bombardment is the most appropriate approach. Implantation of Ni on Ni has led to a modest enhancement of the surface area, but not to electrocatalytic effects [279]. On the other hand, Pt bombarded with neutrons has shown an increase in the activity for hydrogen evolution [280]. However, it has been suggested that this is not related to the formation of surface defects, but rather to the effect of the radioactivity induced on the electrode and on the electrolyte. 

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