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Susceptibility fundamental

Electric motors are susceptible to a variety of forcing functions that cause instability or imbalance. The narrow-bands established to monitor the fundamental and other harmonics of actual running speed are useful in identifying mechanical imbalance, but other indices also should be used. [Pg.701]

Hurst (19) discusses the similarity in action of the pyrethrins and of DDT as indicated by a dispersant action on the lipids of insect cuticle and internal tissue. He has developed an elaborate theory of contact insecticidal action but provides no experimental data. Hurst believes that the susceptibility to insecticides depends partially on the cuticular permeability, but more fundamentally on the effects on internal tissue receptors which control oxidative metabolism or oxidative enzyme systems. The access of pyrethrins to insects, for example, is facilitated by adsorption and storage in the lipophilic layers of the epicuticle. The epicuticle is to be regarded as a lipoprotein mosaic consisting of alternating patches of lipid and protein receptors which are sites of oxidase activity. Such a condition exists in both the hydrophilic type of cuticle found in larvae of Calliphora and Phormia and in the waxy cuticle of Tenebrio larvae. Hurst explains pyrethrinization as a preliminary narcosis or knockdown phase in which oxidase action is blocked by adsorption of the insecticide on the lipoprotein tissue components, followed by death when further dispersant action of the insecticide results in an irreversible increase in the phenoloxidase activity as a result of the displacement of protective lipids. This increase in phenoloxidase activity is accompanied by the accumulation of toxic quinoid metabolites in the blood and tissues—for example, O-quinones which would block substrate access to normal enzyme systems. The varying degrees of susceptibility shown by different insect species to an insecticide may be explainable not only in terms of differences in cuticle make-up but also as internal factors associated with the stability of oxidase systems. [Pg.49]

There is no reason to think that the other kind of hypothetical module, the kind exemplified by the rape module that directs different responses to different situations, will be any less susceptible to developmental variation than quasi-deterministic modules such as the homosexuality module. Plus, for that matter, there is no particular reason to suppose that there will be less initial genetic variability in cases such as the rape module. So perhaps the perspectives of evolutionary psychology and behavioural genetics should not be seen as fundamentally disparate. [Pg.240]

There is a fundamental difference between the uniform spin chain on one hand and the alternated spin chain or spin ladder on the other. Indeed, in the latter cases, the ground state is the singlet state and the susceptibility thus goes to zero at the lowest temperatures, with an activated part of the susceptibility between 0 and T (Xmax)- On the other hand, as shown by Bonner and Fisher [65], in the uniform spin... [Pg.173]

The model shown in Scheme 2 indicates that a change in the formal oxidation state of the metal is not necessarily required during the catalytic reaction. This raises a fundamental question. Does the metal ion have to possess specific redox properties in order to be an efficient catalyst A definite answer to this question cannot be given. Nevertheless, catalytic autoxidation reactions have been reported almost exclusively with metal ions which are susceptible to redox reactions under ambient conditions. This is a strong indication that intramolecular electron transfer occurs within the MS"+ and/or MS-O2 precursor complexes. Partial oxidation or reduction of the metal center obviously alters the electronic structure of the substrate and/or dioxygen. In a few cases, direct spectroscopic or other evidence was reported to prove such an internal charge transfer process. This electronic distortion is most likely necessary to activate the substrate and/or dioxygen before the actual electron transfer takes place. For a few systems where deviations from this pattern were found, the presence of trace amounts of catalytically active impurities are suspected to be the cause. In other words, the catalytic effect is due to the impurity and not to the bulk metal ion in these cases. [Pg.400]

Third-order susceptibilities of the PAV cast films were evaluated with the third-harmonic generation (THG) measurement [31,32]. The THG measurement was carried out at fundamental wavelength of 1064 nm and between 1500 nm and 2100 nm using difference-frequency generation combined with a Q-switched Nd YAG laser and a tunable dye laser. From the ratio of third-harmonic intensities I3m from the PAV films and a fused quartz plate ( 1 thick) as a standard, the value of x(3) was estimated according to the following equation derived by Kajzar et al. [33] ... [Pg.322]

Figure 27 shows spectra of third-order susceptibility x(3) of the oriented MOPPV LB film. Owing to the orientation of MOPPV chains, anisotropy of x(3) was observed. The x(3) values of the LB film, which is enhanced by the three photon resonance, are maximized at a fundamental wavelength of 1600 nm, as observed in a MOPPV cast film. The maximum values of X ( 3) and are 3.2 x 10 10 esu... [Pg.329]

Coronaridine subtype alkaloids are widely spread in Tabernaemontana. The iboga skeleton is particularly susceptible to oxidation at aminomethylenes C-3 and C-5 and at benzylic C-6. Very often, the fundamental compounds are accompanied by the oxidation products at these positions. [Pg.89]


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See also in sourсe #XX -- [ Pg.110 ]




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