Microstructured single-phase modeling

The microstructure and morphology of thick single-phase films have been extensively studied for a wide variety of metals, alloys, and refractory compounds. The structure model first proposed is shown in Figure 6 (10). It was subsequently modified as shown in Figure 7 (10,11). 

The microstructure and morphology of thick single-phase films have been extensively studied for a wide variety of metals, alloys, and refractory compounds. Structural models have been proposed (12,13). Three zones with different microstructure and surface morphology were described for thick (tens of micrometers) deposits of pure metal. At low temperature (< 0.3 Tm ), where Tm is the melting point (K) of the deposit metal, the surface mobility of the adatoms is reduced, and the deposit was reported to grow as tapered crystallites. The surface is not full density (Zone 1). At higher substrate temperature (0.3-0.45 Tm ), the surface mobility increases. The surface... 

To model the microstructure and evaluate the thermoelectric properties, we used following simple equivalent electric circuit model shown in Figure 2. We considered the two phase composite as a cluster pararrel network circuit. Setting for each cluster the characteristic single phase physical property, and settle the material composition to the cluster number ratio, we can simulate the total thermopower of the system by Millman s theorem of d.c. circuit. 

In the two-medium treatment of the single-phase flow and heat transfer through porous media, no local thermal equilibrium is assumed between the fluid and solid phases, but it is assumed that each phase is continuous and represented with an appropriate effective total thermal conductivity. Then the thermal coupling between the phases is approached either by the examination of the microstructure (for simple geometries) or by empiricism. When empiricism is applied, simple two-equation (or two-medium) models that contain a modeling parameter hsf (called the interfacial convective heat transfer coefficient) are used. As is shown in the following sections, only those empirical treatments that contain not only As/but also the appropriate effective thermal conductivity tensors (for both phases) and the dispersion tensor (in the fluid-phase equation) are expected to give reasonably accurate predictions. 

The microstructure and morphology of thick single phase films have been extensively studied for a wide variety of metals, alloys and refractory compounds. The structural model was first proposed by Movchan and Demchishin Figure 14 was subsequently modified by Thornton (Figure 15). Movchan and Demchishin s diagram was arrived at from their studies on deposits of pure metals and did not include the transition zone of Thornton s model. Zone T. This is not prominent in pure metals or single phase alloy deposits but becomes quite pronounced in deposits of refractory compounds or complex alloys produced by evaporation and in all types of deposits produced in the presence of partial pressure of inert or reactive gas, as in sputtering or ARE type processes. 

The chemistries utilized in gas-phase technologies employ the same Ziegler-Natta (314,315) and single-site (metallocene) catalysts (313) described in the processes included below. In gas-phase systems, however, the catalysts are generally solid-supported, but produce the same range of polybutadiene microstructures inherent to the nonsupported catalyst. Several patents also include anionic polymerization systems as useful in gas-phase processes (378). Kinetic modeling work has also been done to better predict the gas-phase polymerization behavior of 1,3-butadiene (379). 

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