Phenomenological aspects

The ablation is quantified by means of the ablation rate, i.e. the ablated depth per pulse. Generally, the ablation rate is insignificant at fluences below a threshold jhtence. Above this threshold, the ablation rate increases dramatically. This is demonstrated in Fig. 9.6 [51] for a commercial polyimide. It can also be seen in Fig. 9.6 that the threshold fluence decreases with shortening wavelength. 

A sharp rise in the etch rate at the threshold is found only at the lowest laser wavelength (193 nm). At higher wavelengths, the curves bend smoothly upwards in an exponential fashion, indicating that there is also ablation below the threshold fluence point obtained by extrapolating the hnear portion of the curve to zero ablation rate. This was corroborated by a study on poly(methyl methacrylate) concerning the so-called incubation effect [52]. The latter refers to the phenomenon of the polymer surface being etched less deeply by the initially applied pulses than by subsequent pulses of the same fluence. Actually, material 

As indicated above, emulsions and foams are thermodynamically unstable dispersions. They are distinguished from the dispersions discussed in Chapter 16 in that their dispersed phase is fluid and not solid. This has a number of consequences of which the most important ones are (1) the particles are deformable, (2) the interface between the dispersed and the continuous phases is deformable, which may give rise to interfacial rheological phenomena, and (3) the particles may coalesce. These 

FIGURE 18.1 Schematic representation of (a) spherical and (b) a hexagonal foam. 

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The phenomenological aspects of diffusional mass transfer in adsorption systems can be described in terms of Fick s law ... 

In this chapter we have surveyed the key phenomenological aspects of electrochemical promotion. 

In this chapter, we shall first make a brief review of the phenomenological aspect of Brownian motion and we shall then show how the general transport equation derived in Section II allows an exact microscopic theory to be developed. 

Let us now briefly describe some broader phenomenological aspects of the P-x diagrams for binary solutions, ranging from the ideal solution limit to extreme nonideal deviations of either positive or negative sign. 

Some of the phenomenological aspects of magnetic exchange have been mentioned in Sections 6.6.1.2/3. At the atomic level it is usually introduced by adding a term to the Hamiltonian for the ith atom... 

The theoretical formulation of the collapse of a polymer chain [4,6] and the volume phase transition of gels [1-3] has been developed by utilizing an analogy between the liquefaction of a real gas and the condensation of polymer segments. In fact, this analogy is quite helpful to understand the phenomenological aspect of the collapse of a polymer chain and of a polymer network. However, we do not know to what extent this analogy is valid in reed cases. Because a gel is a solid, the elastic deformation of the network may play an important role in real phase transition processes. 

The simplicity and nevertheless versatility of the model makes it useful for studying phenomenological aspects of autocatalytic reaction. 

To match experimental precision, the energy shift has to be computed up to AE ma7 and even higher order corrections should sometime be included. For this reason the three loop contribution to Ff°pe is required. We have previously reported on our calculation of the three loop slope of the Dirac form factor in [8], where the emphasize was on the phenomenological aspects. Here we would like to discuss some of the methods employed in that calculation in a more detailed way. Nevertheless, all important consequences of our result are presented as well. 

Goldstein, M. Phenomenological aspects of the glass transition. Submitted to "Modem Aspects of vitrous State , Editor J. D. McKenzie. London Butterworth Co. Ltd. 1963. 

We propose that a redox/antioxidant dysregulation due to GSH deficit could represent a vulnerability factor at the early phase of brain development in at least a subgroup of schizophrenia patients. Combined with other genetic factors and environmental factors, such as stress, obstetrical complications or viral infections, it could favor the development of the disease. The role of the GSH deficit proposed allows integration in a causal way many phenomenological aspects of schizophrenia. It is compatible with both the DA and the glutamate/NMDA hypotheses and with the neuropathological observations. In contrast to... 

In the present text we shall begin with a study of the phenomenological aspects of kinetic systems and then proceed to a critique of the bases for a molecular interpretation of the processes in these systems. 

By contrast to the oxidation of higher alkanes, there is no qualitative way of distinguishing evidence for a diperoxy radical mechanism during the low-temperature oxidation of propane. It is possible that the considerably lower reactivity of propane than that of higher alkanes, as demonstrated by phenomenological aspects (Section 6.4.4), may be explained by the absence of these types of processes. The matter may not be resolved until more insight is obtained from numerical modelling and simulation of experimental results. 

One of the most important phenomenological aspects of electrocatalysis is the dependence of standard rate constants or exchange current densities, Iq (see Section III), for the reaction concerned on the properties and chemical identity of the electrode metal (Fig. 15) and/or the state and orientation of its surface. In fact, this is the basis of the good deffnition of electrocatalysis proposed by Busing and Kauzmann (12). 

The brief review of the vast literature on the phenomenological aspects of adsorption of aromatic solutes has highlighted studies that provide clues, either explicitly or implicitly, to the optimization of carbon surface chemistry for removal of specific pollutants from aqueous streams. Here we make an attempt to synthesize the available information. In Section V we then offer suggestions regarding a comprehensive model of adsorption of organic (and inorganic) solutes. 

Two phenomenological aspects, and their explanation, are of primary interest (I) the demonstration that carbons are amphoteric. solids, albeit quite complex ones (see Section II), and (2) the analysis of the effects of pH on uptakes of weak electrolytes. The studies in which the latter effect is merely noted are reviewed... 

Fundamental studies on metal deposition and electrocrystallization processes started in the first half of the twentieth century with thework of Volmer [6.3], Erdey-Gruz and Volmer [6.4], Brandes [6.5], Gorbunova and Dankov [6.6], and Kaischew [6.7]. A first attempt at a systematic study of the phenomenological aspects of electrodeposited metal coatings was made by Fischer [6.8]. 

In this chapter we review some of the key phenomenological aspects of promotion, electrochemical promotion, and metal-support interactions, underline their kinetic similarities and common fundamental origin on the basis of surface spectroscopic and theoretical investigations, including the new concept of the absolute potential of supports, and discuss some key experiments that prove their identical nature, i.e., catalysis in presence of a controllable double layer at the catalyst-gas interface. 

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