Wave effect

K.P. Staudhammer, Shock Wave Effects and Metallurgical Parameters, in IMPACT 1987 (edited by C.Y. Chiem, H.-.D. Kunze, and L.W. Meyer), Duetsche Gesellschaft fur Metallkunde, Oberursel, West Germany, 1988, 93 pp. 

W. Lauterborn, Appl. Sci. Res. 38, 165-178 (1982) and Finite-Amplitude Wave Effects in Fluids, Proc. 1973 Symp. (L. Bjdrnd, ed.), pp. 195-202, IPC Science and Technology Press, Guilford, England, 1974. 

PLANAR OPTICAL SENSORS AND EVANESCENT WAVE EFFECTS... 

Planar Optical Sensors and Evanescent Wave Effects... 

Evanescent Wave Effects and Fluorescence-Based Optical Sensors... 

While planar optical sensors exist in various forms, the focus of this chapter has been on planar waveguide-based platforms that employ evanescent wave effects as the basis for sensing. The advantages of evanescent wave interrogation of thin film optical sensors have been discussed for both optical absorption and fluorescence-based sensors. These include the ability to increase device sensitivity without adversely affecting response time in the case of absorption-based platforms and the surface-specific excitation of fluorescence for optical biosensors, the latter being made possible by the tuneable nature of the evanescent field penetration depth. 

The polarity of ground and transition states are a priori identical, because no charges are developed during the reaction path. Following this rule, spedfic micro-wave effects would not be expected for these reactions, as has been verified when the reactions were performed in a nonpolar solvent [5, 6]. Solvent effects in these reactions are also small, or negligible, for the same reasons (Fig. 3.6) [46]. 

The transition states are composed of loose ion pairs in so far as they involve a charge-delocalized anion, thereby enhancing polarity compared with the ground states (in which the ion pairs are tighter), because of an increase in anionic dissociation as the more bulky product anion is formed. As a consequence, specific micro-wave effects, directly connected to polarity enhancement, should depend on the structure of reactive ion pairs in the GS ... 

The position of the transition state along the reaction coordinates in relation to the well-known Hammond postulate [53] will now be considered. If the activation energy, AG+, of a reaction is only small the TS looks like the GS (it is depicted as a reactant-like transition state ). Consequently, the polarity is only slightly modified between the GS and TS during the course of the reaction and only weak specific micro-wave effects can be foreseen under these conditions. 

As a further consequence of these assumptions, it might be foreseen that micro-wave effects could be important in determining the selectivity of some reactions. When competitive reactions are involved, the GS is common for both processes. The mechanism occurring via the more polar TS could, therefore, be favored under the action of microwave radiation (Scheme 3.7). 

Ester aminolysis, in general, occurs under harsh conditions that require high temperatures and extended reaction periods or the use of strong alkali metal catalysts. An efficient solid state synthesis of amides from nonenolizable esters and amines using KO Bu under the action of microwave irradiation [97] has been described. The reaction of esters with octylamine was extensively studied to identify possible micro-wave effects [98] (Eq. (45) and Tab. 3.20). 

HVAC blast attenuators are similar to blast dampers except they do not have any moving parts. They are stationary devices used to reduce or lessen the blast wave effects by reducing the interior increase in pressure. They are intended for short blast durations. Manufacturers will provide the necessary design information. 

An additional complication associated with the standing wave effect occurs for the exposure of resist over topography. When a resist is spin-coated onto a substrate containing steps, the resist thickness varies from one area to another on the wafer. Since the standing wave effect is a strong function of resist thickness, exposure variations resulting from variation in resist thickness in the vicinity of the step result in changes in linewidth. 

Two component, positive photoresists (see Section 3.5.b) represent systems with unusual exposure characteristics caused by the standing wave effect (see Section 2.1.f) and "bleaching" or change in optical density during exposure (see Sections 3.5 and 3.9). Both of these phenomena result in nonlinear exposure throughout the thickness of the resist film, and result in uneven developing rates as a function of film thickness, making evaluation of these systems difficult. 

He states that in the last few decades, Russian scientists have been studying with considerable success such questions as the propagation of shock waves, effects of explosions in complex media, effects of a powerful explosion in a nonhomogeneous atmosphere and at-great heights, formation and propagation of shock waves in shallow water, at the surface of a liquid, and in two-phase media. 

A further approximation adopted in theoretical computations is to omit all quantum-mechanical wave effects, which certainly is well justified for the large crossing radii and the small-particle wavelength of around 0.2 A. 

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