Self phenomena

Materials are also classified according to a particular phenomenon being considered. AppHcations exploiting off-resonance optical nonlinearities include electrooptic modulation, frequency generation, optical parametric oscillation, and optical self-focusing. AppHcations exploiting resonant optical nonlinearities include sensor protection and optical limiting, optical memory appHcations, etc. Because different appHcations have different transparency requirements, distinction between resonant and off-resonance phenomena are thus appHcation specific and somewhat arbitrary. 

This phenomenon is caused by self-excitation of the blade and is aero-elastic. It must be distinguished from classic flutter, since classic flutter is a coupled torsional-flexural vibration that occurs when the freestream velocity over a wing or airfoil section reaches a certain critical velocity. Stall flutter, on the other hand, is a phenomenon that occurs due to the stalling of the flow around a blade. 

As materials chemistry has developed, it has come to pay more and more attention to that archetypal concern of materials scientists, microstructure. That concern came in early when the defects inherent in non-stoichiometric oxides were studied by the Australian. I.S. Anderson and others (an early treatment was in a book edited by Rabenau 1970), but has become more pronounced recently in the rapidly growing emphasis on self-assembly of molecules or colloidal particles. This has not yet featured much in books on materials chemistry, but an excellent recent popular account of the broad field has a great deal to say on self-assembly (Ball 1997). The phenomenon of graphoepitaxy outlined in Section 10.5.1.1 is a minor example of what is meant by self-assembly. 

Reductionist World-View Holistic World-View a shift away from a long held belief that complex self-organized behavior requires a complex underlying dynamics and/or substructure towards the new notion that complexity is an emer-gent/holistic phenomenon that often arises from the interactions among a large assemblage of otherwise simple parts i.e. the properties of the parts must be understood as a dynamics of whole. 

As a closed trajectory in the phase plane means obviously a periodic phenomenon, the discovery of limit cycles was fundamental for the new theory of self-excited oscillations. 

This analogy has been found to be very useful in investigating more complicated situations. For instance, in applications one often encounters the so-called phenomenon of a hard self-excitation. The... 

L. Mandelstam and N. Papalexi performed an interesting experiment of this kind with an electrical oscillatory circuit. If one of the parameters (C or L) is made to oscillate with frequency 2/, the system becomes self-excited with frequency/ this is due to the fact that there are always small residual charges in the condenser, which are sufficient to produce the cumulative phenomenon of self-excitation. It was found that in the case of a linear oscillatory circuit the voltage builds up beyond any limit until the insulation is ultimately punctured if, however, the system is nonlinear, the amplitude reaches a stable stationary value and oscillation acquires a periodic character. In Section 6.23 these two cases are represented by the differential equations (6-126) and (6-127) and the explanation is given in terms of their integration by the stroboscopic method. 

Patients seen for flashbacks are treated with oral diazepam (15—30 mg/day for adults) if symptoms of anxiety are severe (Rumack 1987). Neuroleptics, especially haloperidol, have been implicated in a transient increase in visual flashbacks and are not recommended (Moskowitz 1971 Strassman 1984). Risperidone and selective serotonin reuptake inhibitors may also worsen symptoms of hallucinogen persisting perception disorder (Halpern and Pope 2003). The patient needs assurance of the self-limiting nature of the phenomenon and its decreasing frequency of reoccurrence with time. The patient should be reminded that any future use of hallucinogens or marijuana may precipitate similar symptoms (Strassman 1984). 

Coacervation occurs in tropoelastin solutions and is a precursor event in the assembly of elastin nanofibrils [42]. This phenomenon is thought to be mainly due to the interaction between hydro-phobic domains of tropoelastin. In scanning electron microscopy (SEM) picmres, nanofibril stmc-tures are visible in coacervate solutions of elastin-based peptides [37,43]. Indeed, Wright et al. [44] describe the self-association characteristics of multidomain proteins containing near-identical peptide repeat motifs. They suggest that this form of self-assembly occurs via specific intermolecular association, based on the repetition of identical or near-identical amino acid sequences. This specificity is consistent with the principle that ordered molecular assembhes are usually more stable than disordered ones, and with the idea that native-like interactions may be generally more favorable than nonnative ones in protein aggregates. 

Gonzalez, M., Borghi, R., and Saouab, A., Interaction of a flame front with its self-generated flow in an enclosure The "tulip flame" phenomenon. Combustion and Flame, 88,201-220,1992. 

The first phenomenon observed is the improved resistance of these materials to combustion, in a way that they may be classified as intrinsically self-extinguishing substrates. For instance, the LOI value for PTFEP is reported to be 48 [452], which is much higher than reported for classical organic plastics [283], while phosphazene fluoroelastomers have been considered as fire-retardant materials since the very beginning of their preparation and utilization [562]. Similarly to aryloxy- and arylamino- substituted POPs [389,390] (vide infra),it may be expected that the flame-resistance properties of phosphazene fluoroelastomers could be successively exported to stabihze organic macromolecules when blended with these materials. 

Adsorption phenomena from solutions onto sohd surfaces have been one of the important subjects in colloid and surface chemistry. Sophisticated application of adsorption has been demonstrated recently in the formation of self-assembhng monolayers and multilayers on various substrates [4,7], However, only a limited number of researchers have been devoted to the study of adsorption in binary hquid systems. The adsorption isotherm and colloidal stabihty measmement have been the main tools for these studies. The molecular level of characterization is needed to elucidate the phenomenon. We have employed the combination of smface forces measmement and Fomier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR) to study the preferential (selective) adsorption of alcohol (methanol, ethanol, and propanol) onto glass surfaces from their binary mixtures with cyclohexane. Om studies have demonstrated the cluster formation of alcohol adsorbed on the surfaces and the long-range attraction associated with such adsorption. We may call these clusters macroclusters, because the thickness of the adsorbed alcohol layer is about 15 mn, which is quite large compared to the size of the alcohol. The following describes the results for the ethanol-cycohexane mixtures [10],... 

Recent publications on the thermal stability of proteins organized in dense solid films, deposited by LB (Nicolini et al. 1993, Facci et al. 1994, Erokhin et al. 1995) and by self-assembling (Shen et al. 1993), leave several questions unanswered, hi particular, it is still not completely clear which parameter is responsible for this phenomenon. Two main factors are discussed when speaking about induced thermal stabihty, namely, decreased water content and molecular close packing (Nicolini et al. 1993). It seems that both of them work in parallel, and unfortunately it is difficult to settle directly which one plays the dominant role. 

The process, once initiated, is self-sustaining and may become more accelerated with time because the atrophy and intestinal metaplasia are progressive lesions and lead to further loss of parietal cells and incrased bacterial colonization of the mucosa. The initial mutations transform gastric cells into mature intestinal-type cells. Further superimposed mutations transform metaplastic cells into progressively dysplastic cells and eventually into neoplastic cells. This is a process of loss of differentiation which implies a multihit phenomenon which could be explained on the basis of continued formation of minute amounts of nitroso compounds over many years. 

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