Stabilization mechanism for

Bradley, J.S. et al., Surface spectroscopic study of the stabilization mechanism for shape-selectively synthesized nanostructured transition metal colloids, J. Am. Chem. Soc., 122, 4631, 2000. 

Crannell, B. S., Eighmy, T. T., Krzanowski, J. R. Eusden, J. D. Jr. 1999. Phosphate stabilization mechanisms for heavy metals in electric arc furnace smelter dusts. In Nikolaidis, N., Erkey, C. Smets, B. (eds) Hazardous Wastes and Hazardous Materials. Technomic Publishing, Lancaster, Pennsylvania, 561-570. 

A detailed analysis of the X-ray crystal structures of wild-type / NB E and thermostable 8G8 has been carried out (Spiller et al., 1999). Detailed stabilization mechanisms for the various mutations are presented in the chapter by Orencia, Hanson, and Stevens in this volume we will only... 

Proposed Stabilization Mechanisms for Mutations in pNB Esterase, Subtilisin E, and Subtilisin S41... 

It is not the purpose of this paper to review or expound on the well-documented stabilization mechanisms for PVC. Nor will we consider the other well known auxiliaries to PVC stabilization such as phosphites, epoxies, and hindered phenols. Rather, attention will be paid to only the primary metallic and organometallic stabilizers, the principle elements illustrated in Table I. The metal soap derivatives of the Group... 

Koczo, K., Nikolov, A.D., Wasan, D.T., Borwankar, R.P., Gonsalves, A. Layering of Sodium Caseinate Submicelles in Thin Liquid Films - A New Stability Mechanism for Food Dispersions. J. Colloid Interface Sci., 1996, 178, p. 694. 

The elimination of labile chlorine atoms from the polymer backbone is the most important stabilization mechanism for PVC. Dialkyl tin maleates (e.g., DBTM) and thioglycollates (e.g., DOTG, AO 36, Table 1) function by eliminating HCl, see Reaction 7. In addition, the maleates also act by removing the unsaturation and limiting color development, whereas the thioglycollates have an additional peroxidolytic function. " ... 

Experiments in which an unstabilized PP film was shielded by a benzophenone or benzotriazole type UVAs showed that both could protect the unstabilized PP film by UV absorption. However, a film shielded by a benzophenone-type UVA-containing film showed a significantly faster degradation than a film containing this stabilizer. This clearly demonstrates that their protection is not only by U V absorption but also by other mechanisms. In contrast, a film shielded with a benzotriazole type UVA is considerably more stable than the shielding film itself, which clearly indicates the dominating role of UV absorption as main stabilization mechanism for this type of UVA [15,16],... 

The mechanisms for the stabilization of nematode eggshells are known with less certainty than in trematodes. In A. suum, eggshells recovered from the host feces are brown and relatively insoluble compared to shells of eggs recovered from the uterus or laid in vitro. Phenols have been extracted from the eggshells of A. suum, but phenol oxidase has not been demonstrated (16). Phenols have also been demonstrated in the eggshell of Trichuris ovis (17) and the presence of phenol oxidase in female Trichuris suis has been demonstrated (18) and localized to the eggshell (Fetterer, unpublished observation). The role of sclerotinization or of other stabilization mechanisms for nematode eggshell proteins remains undefined. 

Cationic polymerization of vinyl monomers involves the highly reactive carbenium ions, which can only be formed when they are stabilized by the substituents on the vinyl group. Stabilization of the carbenium ion can be achieved by resonance structures, as is the case for vinyl ether and styrenic monomers, or by an inductive effect, which is the stabilizing mechanism for 1,1-disubstituted alkenes. Despite this stabilization, the reactivity of such carbenium ions is still very high, giving rise to the occurrence of side reactions, such as isomerization, hydride abstraction, as well as various transfer reactions. Moreover, carbocationic polymerizations are very sensitive to minor nucleophilic impurities. Nonetheless, in recent years a range of less sensitive polymerization initiators have been developed that can be used in aqueous environment [20]. 

The Forster mechanism is based on a dipole-dipole interaction and is usually observed in the quenching of excited states. It has been considered as a possible stabilization mechanism for typical UV absorbers with extinction coefficients greater than 10,000. The distance between chromophore and quencher in this process may be as large as 5 or even 10 nm, provided there is a strong overlap between the emission spectrum of the chromophore and the absorption spectrum of the quencher. 

Fig. 22 Stabilization mechanism for the self-stabilized magnetic polymeric composite nanoparticles obtained by emulsifier-free miniemulsion polymerization. Reprinted from [184] with permission...

Parker et al. [49] altered the stabilization mechanism for styrene-butadiene latex prepared by emulsion polymerization from anionic to cationic so that they could get a spontaneous flocculation with aqueous montmorillonite slurry and the latex. Evaluation of the rubber nanocomposite prepared in this manner gave dramatic increases in modulus, strength, percent elongation, and decrease in hysteresis. 

The average number n is mainly determined by the pump power Pp (Sect. 5.1.3). If at a given value of Pp the number of photons increases because of an amplitude fluctuation of the induced emission, saturation of the amplifying transition in the active medium reduces the gain and decreases the field amplitude. Thus saturation provides a self-stabilizing mechanism for amplitude fluctuations and keeps the laser field amplitude at a value Es (n) /. ... 

Liquid-Membrane Electrodes. The electroactive phase in this type of electrode consists of a liquid that has been stabilized mechanically. For this purpose the electroactive components may be dissolved in a highly viscous and apolar organic solvent such as one of the higher alcohols or paraffin. A porous material (e.g., commercial membrane filters such as Sartorius cellulose nitrate with pore diameters of about 0.45 pm), are initially made hydrophobic with, e.g., hexamethyl disilazane and then soaked with this solution and introduced in place of the solid membrane in an electrode of the type described above. More frequently, however, the liquid is not fixed in a porous material, but rather embedded into a high molecular mass polymer like PVC. In this case the plasticizer (normally present at a concentration of about 66% by weight) acts as a solvent for the electroactive component (the concentration, which seldom exceeds 1 % ). Simplified construction schemes for these two types of electrodes are illustrated in Figure 13. 

It can be assumed that the development of a stabilization mechanism for the composite site NFe 4. .. NH" and/or the enhancement of the site density of Me-PANl-C catalysts will lead to a further breakthrough in the development of NPMC. Both strategies might be successful in the next few years. 

Fig. 11. Proposed stabilizing mechanism for asphaltenes in petroleum by resin molecules ( ).

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