Substrate thermal properties

To rationalize the isothermal assumption, Dykhuizen 39() discussed two related physical phenomena. First, heat may be drawn out of the substrate from an area that is much larger than that covered by asplat. Thus, the 1 -D assumption in the Stefan problem becomes invalid, and a solution of multidimensional heat conduction may make the interface between a splat and substrate closer to isothermal. Second, the contact resistance at the interface is deemed to be the largest thermal resistance retarding heat removal from the splat. If this resistance does not vary much with substrate material, splat solidification should be independent of substrate thermal properties. Either of the phenomena would result in a heat-transfer rate that is less dependent on the substrate properties, but not as high as that calculated by Madej ski based on the... 

High demands are placed on the substrate material of disk-shaped optical data storage devices regarding the optical, physical, chemical, mechanical, and thermal properties. In addition to these physical parameters, they have to meet special requirements regarding optical purity of the material, processing characteristics, and especially in mass production, economic characteristics (costs, processing). The question of recyclabiUty must also be tackled. 

In appUcations in which electrical conductivity is required, metals, copper, tungsten, molybdenum, and Kovar [12606-16-5] are the preferred chip-carrier materials. Metals have exceUent thermal conductivities. Tables 2 and 3 Ust the various materials used for substrates, along with their mechanical, electrical, and thermal properties. 

Gallium arsenide is epitaxially deposited on a silicon substrate and the resulting composite combines the mechanical and thermal properties of silicon with the photonic capabilities and fast electronics of gallium arsenide. 

The chaotropic properties of many chemical compounds prevent the H2O cage structures necessary for the formation of solvates and thus facilitate the transfer of nonpolar molecules between nonaqueous and aqueous phases. Water is incombustible and nonflammable, odorless and colorless, and is universally available in any quality important prerequisites for the solvent of choice in catalytic processes. The DK and d can be important in particular reactions and are advantageously used for the analysis and control of substrates and products. The favorable thermal properties of water make it highly suitable for its simultaneous dual function as a mobile support and heat transfer fluid, a feature that is utilized in the RCH/RP process (see below). 

Finally, predicted and simulated catalyst temperatures are compared in Fig. 23. These temperatures were measured by a thermocouple inserted into the catalyst 25 mm from the front face, as measured in the axial direction. The agreement between measurement and prediction is good, indicating that the thermal properties used in the model for the catalyst/substrate are reasonable. 

A study is presented of the synthesis and properties of the novel synthetic zeolite omega. The synthesis variables and kinetics of formation are discussed, as well as the ion exchange, sorption, and thermal properties. By decomposition of imbibed tetra-methylammonium ions and exhaustive treatments of the zeolite with ammonium ions, a pure hydrogen form can be obtained which is a suitable substrate for the preparation of hydrocarbon conversion catalysts. Several catalysts were prepared and utilized to isomerize n-hexane, and to hydrocrack a heavy gas oil. 

In the absence of good quality single crystal samples, the physical properties of indium nitride have been measured on non-ideal thin films, typically ordered polycrystalline material with crystallites in the 50 nm to 500 nm range. Structural, mechanical and thermal properties have only been reported for epitaxial films on non-lattice-matched substrates. 

The substrate also has a role to play in the evaporation of a droplet, with the evaporation rate of droplets being limited by the substrate s thermal properties this is especially the case for high evaporation rates. When a droplet is deposited onto a substrate, two extreme cases can occur. If the substrate is a perfect thermal insulator then the evaporation rate is altered by changes in the droplet-vapour interface area. However, if the substrate is a perfect thermal conductor then the evaporation rate is also affected by a second mechanism, namely the heat transfer between the substrate and the droplet. In this second situation, the evaporation rate is higher than that of a droplet sitting on a thermal insulator. 

David S, Sefiane K, Tadrist L. (2007) Experimental investigation of the effect of thermal properties of the substrate in the wetting and evaporation of sessile drops. Colloids Surf A Physicochem Eng Asp 298 108-114. 

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