Image degradation

A second approach modifies the CA resist chemistry. Eor example, researchers have introduced basic additives into the resist formulation to minimize the impact of surface contamination of the resist film (82,83). A resist that already contains added base (and consequendy requites a larger imaging dose) should be less affected by the absorption of small amounts of basic contaminants. Systems of this type have been claimed to have improved resolution as well. The rationalization here is that the acid that diffuses into the unexposed regions of the resist film is neutralized and does not contribute to image degradation (84,85). 

Carasso AS, Sanderson JG, Hyman JM (1978) Digital removal of random media image degradations by solving the diffusion equation backwards in time. SIAM J Numer Anal 15 344-367... 

Figure 20. Results of a family of experiments with ferrous/ferric DTPA buffers. Each vertical line of dots corresponds to an experiment like the middle (triangles) plot of D/Log E of Figure 19. There is a region of increasing latent image degradation from —160 mv to —100 mv and beyond. None of the films going into this data plot were treated by optical latensificalion (56C).

Figure 21. A family of experiments, of the silver density difference produced by treating film samples paralleling Figure 20 with optical latensification after latent image degradation by one of several buffer solutions.

For relatively long propagation paths through the atmosphere, system spread function and MFF are limited primarily by atmosphere—rather than instrumentation— phenomena. Here, we are concerned with the MFF or MCF of the atmosphere. Each of the various types of image degradation produced by the atmosphere will be considered now quantitatively from the standpoint of MFF or MCF. Use of MFF or MCF thory in imaging system design is discussed in the literature (see Kopeika, 1998, for example). 

Elson, J. M., and Bennett, H. E. Image degradation caused by direct scatter from optical components into the image plane. No. 1013. SPIE. 

Recently, PLLA implants have also found applications in spine surgery [79]. Metallic spinal instrumentation and implants have been developed to provide immediate structural stability until bone fusion occurs. However, these implants have caused several complications including implant migration and failure, imaging degradation in MRI, and stress shielding that has been mentioned previously [79]. 

Drasdo, N., Cox, W., and Thompson, D.A. 1987a. The effects of image degradation on retinal illuminance and pattern responses to checkerbo d stimuli. Doc. Qphthal. 66 267-275. 

Metal complexes play many roles in biological systems as catalysts, stimuli responsive centers and structural materials. Introduction of metals into synthetic biomaterials can result in similarly diverse functions, useful for imaging, degradation, and bioactivity. Biomaterials with single well-defined metal centers can result from the combination of coordination chemistry and controlled polymerizations. Efforts in our laboratory to adapt these reactions to bipyridine (bpy) and dibenzoylmethane (dbm) ligand and metal complex reagents, and to explore the ways that metals and polymers mutually affect each other are reviewed below, with poly(lactic acid) (PLA), poly(ethylene glycol) (PEG), poly(ethylenimine) (PEI), and selected acrylate systems, poly(t-butyl acrylate) (PtBA) and poly(acrylic acid) (PAA), as examples. 

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