Engineering applications, dielectric

Dispersion. Dispersion or London-van der Waals forces are ubiquitous. The most rigorous calculations of such forces are based on an analysis of the macroscopic electrodynamic properties of the interacting media. However, such a full description is exceptionally demanding both computationally and in terms of the physical property data required. For engineering applications there is a need to adopt a procedure for calculation which accurately represents the results of modem theory yet has more modest computational and data needs. An efficient approach is to use an effective Lifshitz-Hamaker constant for flat plates with a Hamaker geometric factor [9]. Effective Lifshitz-Hamaker constants may be calculated from readily available optical and dielectric data [10]. 

Polyimides are of particular interest for many engineering applications due to their excellent thermal and mechanical properties in the aerospace and microelectronics industries. Many important applications have been developed (1,2 The poiyimide siloxane segmented copolymers have been of particular interest since incorporation of amine functionalized polysiioxanes into polyimides have resulted in improved solubility and processability, decreased water absorption, atomic oxygen resistance (3), lower dielectric constants (4) and enhanced adhesion (5). The copolymers are generally synthesized as shown in Scheme 1 from a combination of a dianhydride and... 

Additional types of polarization (evident in usually small atomic and electronic absorption, dielectric loss, peaks) occur at higher frequencies in the infrared and visible range. With some exceptions, these peaks are not important in engineering applications. The dielectric constant at frequencies above those for which dielectric absorption occurs is small and approximately equal to the square of the optical index of refraction. 

Industrial Power Engineering and Applications Handbook Table 11.4 Test voltages for conducting dielectric tests... 

Source Liu, C. et at, Electro-statically stricted polymers (ESSP), SPIE Conference on Electroactive Polymer Actuator and Devices, Newport Beach, California, March 1999, SPIE Vol. 3669,0277-786X/99 Kombluh, R. et at, Application of Dielectric Elastomer EAP Actuators, SPIE— the International Society for Optical Engineering, Bellingham, Washington, 2001, Chapter 16. 

The successful application of the sol-gel route has been realized in the International technological practice of many branches of the industries—electronics, optics, construction of engines, nuclear energetics, chemical, and food industry equipment. Among these materials are ferro-, piezo-, and dielectrics, solid electrolytes, refractory materials, membranes, protective and decorative coatings, and also films with special optical and electrophysical properties, like hightemperature superconductors. 

Policastro PP, Lupinski JH, Hernandez PK (1988) Siloxane polyimides for interlayer dielectric applications, Polymeric materials Science Engineering 59 209... 

The applicable fundamental concepts of nonlinear integrated optics for SHG were outlined decades ago and can be found in a number of review papers [6-8]. The basic theory as applied to organic materials and polymers is of course unchanged from that for dielectric materials and these papers are still very useful. Some twenty plus years ago, nonlinear integrated optical experiments started to be conducted, but mostly on inorganics and crystals. The specific field of amorphous and semi-ordered organics came when the chemical engineering of nonlinear chromophores was developed. 

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