Main effect

Chemists have formulated a variety of concepts of a physicochemical or theoretical nature in their endeavors to order their observations on chemical reactions and to develop insight into the effects that control the initiation and course of chemical reactions. The main effects (but not the only ones, by far) influencing chemical reactivity are described below. 

In the X- and y-directions (Figure 49.5b), an ion trajectory is more difficult to visualize. It is essentially the sum of two main effects one a simple oscillation caused by the rapid cyclic alternations of the RF field (Figure 49.5c), the other a more complicated drift or guided motion due to the inhomogeneity of the RF field within the space between all four rods. 

In a diatomic molecule one of the main effects of mechanical anharmonicity, the only type that concerns us in detail, is to cause the vibrational energy levels to close up smoothly with increasing v, as shown in Figure 6.4. The separation of the levels becomes zero at the limit of dissociation. 

Although the compounds were isolated in quantities of only a few milligrams per kilogram of cmde plant leaves, extensive work on a variety of animal tumor systems led to eventual clinical use of these bases, first alone and later in conjunction with other materials, in the treatment of Hodgkin s disease and acute lymphoblastic leukemia. Their main effect appears to be binding tightly to tubuHn, the basic component of microtubules found in eukaryotic cells, thus interfering with its polymerization and hence the formation of microtubules required for tumor proliferation (82). 

The physical and mechanical properties of steel depend on its microstmcture, that is, the nature, distribution, and amounts of its metaHographic constituents as distinct from its chemical composition. The amount and distribution of iron and iron carbide determine most of the properties, although most plain carbon steels also contain manganese, siUcon, phosphoms, sulfur, oxygen, and traces of nitrogen, hydrogen, and other chemical elements such as aluminum and copper. These elements may modify, to a certain extent, the main effects of iron and iron carbide, but the influence of iron carbide always predominates. This is tme even of medium alloy steels, which may contain considerable amounts of nickel, chromium, and molybdenum. 

The main effects are calculated by calculating the difference between results from all high values of a variable and all low values of a variable the result is divided by the number of experiments at each level. For example, for the first variable ... 

Note that all observations are being used to supply information on each of the main effects and each effect is determined with the precision of a fourfold rephcated difference. The advantage of a one-at-a-time experiment is the gain in precision if the variables are additive and the measure of nonadditivity if it occurs (Ref. 40). 

Flexibilized epoxy resins are important structural adhesives [69]. Liquid functionally terminated nitrile rubbers are excellent flexibilizing agents for epoxy resins. This liquid nitrile rubber can be reacted into the epoxy matrix if it contains carboxylated terminated functionalities or by adding an amine terminated rubber. The main effects produced by addition of liquid nitrile rubber in epoxy formulations is the increase in T-peel strength and in low-temperature lap shear strength, without reducing the elevated temperature lap shear. 

Systematic studies on disubstituted thiophenes are scarce, but some differences between the various series of disubstituted thiophenes have been detected. According to Imoto et al., the main effect of substituents in 2,5-disubstitution in thiophenes appears in the wavelength shift, whereas the main effect of substituents in the 2,4-disub-stituted thiophenes appears in the intensity changes of the bands. The intensities of the first absorption band of some 2,6-disubstituted thiophenes have been calculated from the spectroscopic momenta of the substituents. The UV absorption of thiophene was displaced... 

The e.m.f. of a thermogalvanic cell is the result of four main effects (a) electrode temperature, (b) thermal liquid junction potential, (c) metallic thermocouple and (d) thermal diffusion gradient or Soret. 

The main effects of a higher condensing temperature will be a drop in the refrigerating effect, since the liquid enters the expansion valve hotter, and a decrease in volume pumped due to the lower volumetric efficiency. There will also be an increase in the drive motor power. 

The UPS spectra (not shown here) recorded upon Al deposition onto the conjugated thiophene systems shows only small visible changes in the positions of the peaks in the spectra [84]. The main effect is a rapid decrease in intensity, which indicates that a metallic overlayer is formed since the cross-sections for the Al(3p) or Al(3s) are much lower than for the C(2p) or S(3p) orbitals. This is consistent with the Al(2p) XPS spectra discussed above. 

As regards general principles, the main effects are manifested in the region of comparatively high degrees of filling, it does not matter if the case at hand is a hydro-dynamic interaction of the flows around them or a direct intermolecular interaction of the filler s particles. Here we should bear in mind the following decisive principles. 

With crystalline plastics, the main effect of the crystallinity is to broaden the distribution of the relaxation times and extend the relaxation stress too much longer periods. This pattern holds true at both the higher and low extremes of crystallinity (Chapter 6). With some plastics, their degree of crystallinity can change during the course of a stress-relaxation test. This behavior tends to make the Boltzmann superposition principle difficult to apply. 

The antiepileptic drug phenytoin, an orally available class DB antiarrhythmic, is mainly effective in digitalis-induced arrhythmias. This diug exhibits nonlinear pharmacokinetics and a number of side effects including neuropathy, gingival hypetplasia, hepatitis, immunological disorders and suppression of white blood cells. 

Acarbose and Miglitol These agents are specific inhibitors of intestinal glucosidases and reduce the conversion of sucrose and starch to glucose. Their main effect is a delay, not a complete inhibition, of the absorption of carbohydrates. Postprandial blood sugar excursions are effectively reduced. Because a small portion of the carbohydrates enters the colon, their microbial degradation frequently causes flatulence or... 

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