Electrical properties test parameters

Hexamethylcyclotrisilazane and hexamethylcyclotrisiloxane were purified by rectification in vacuum following which their purity was tested by gas chromatography. Plasma polymerizations were carried out in an electrode system described previously ( ). Thin film were deposited in a 20 kHz glow discharge on the surface of stainless steel electrodes or on gold or silicon electrodes in the case of thin layers intended for further studies of electrical properties. All polymerizations were carried out at constant discharge parameters current density j = 1 mA/cm2, discharge duration t = 30 sec, monomer vapour pressure p = 0.3 Torr. 

The Ki-value determination of PVC cable compounds The specific volume resistivity is the most important electrical property of an electrical grade PVC. It is measured on a heavily plasticised product, the cable compound, pressed to a 2 mm. thick sample sheet. Cable manufactures usually test the resistivity of these compounds on cable samples and express the results in a so-called Ki-value. The Ki-value is in fact a volume resistivity value (see below) but measured on a cable sample with tapwater as low potential measuring electrode. A series of Ki-value determinations was performed to investigate the different parameters influencing this quantity. 

For measuring and quantilying the sensor characteristics of integrated piezoelectric transducers, different methods are available. In Section 7.2.2.1 it was shown that by resonant excitation of the structure and the then determined electrical properties, conclusions on electromechanical coupling and the associated efficiencies can be drawn. Another option is to deform the structure by mechanical loads and to measure the resulting electrically induced potentials or charges. This method also has the benefit that the test parameters can be modified and adjusted continuously online. It is also close to potential applications and future practical uses. The measuring principle is shown in Fig. 7.7. 

We have shown in this paper the relationships between the fundamental electrical parameters, such as the dipole moment, polarizability and hyperpolarizability, and the conformations of flexible polymers which are manifested in a number of their electrooptic and dielectric properties. These include the Kerr effect, dielectric polarization and saturation, electric field induced light scattering and second harmonic generation. Our experimental and theoretical studies of the Kerr effect show that it is very useful for the characterization of polymer microstructure. Our theoretical studies of the NLDE, EFLS and EFSHG also show that these effects are potentially useful, but there are very few experimental results reported in the literature with which to test the calculations. More experimental studies are needed to further our understanding of the nonlinear electrooptic and dielectric properties of flexible polymers. 

Molecular dynamic studies used in the interpretation of experiments, such as collision processes, require reliable potential energy surfaces (PES) of polyatomic molecules. Ab initio calculations are often not able to provide such PES, at least not for the whole range of nuclear configurations. On the other hand, these surfaces can be constructed to sufficiently good accuracy with semi-empirical models built from carefully chosen diatomic quantities. The electric dipole polarizability tensor is one of the crucial parameters for the construction of such potential energy curves (PEC) or surfaces [23-25]. The dependence of static dipole properties on the internuclear distance in diatomic molecules can be predicted from semi-empirical models [25,26]. However, the results of ab initio calculations for selected values of the internuclear distance are still needed in order to test and justify the reliability of the models. Actually, this work was initiated by F. Pirani, who pointed out the need for ab initio curves of the static dipole polarizability of diatomic molecules for a wide range of internuclear distances. 

Tests are usually classified by the parameters to be measured -mechanical, thermal, electrical etc. These can be sub-divided to list the actual properties so that under mechanical, for example, there are strength, stiffness, creep etc. This form of classification will be used in this book because of its convenience. However, in terms of the purposes of testing discussed above and considering what is required of the results from a particular method, this classification is not particularly useful. A more generalised way of classifying tests is to consider -... 

For the reasons indicated it is not possible here to cover each material in detail and before going on to make some general observations about basic techniques for finishing one should emphasize that trials in advance with the actual substances to be worked usually are necessary. The testing should cover every aspect relevant to what is required of a component, and obviously it is helpful in this regard if reference can be made to a written Standard or specification. Tests may be of chemical behaviour, electrical, mechanical, physical, and thermal properties, or of some other aspect like performance when exposed to fire or to strong sunlight. The tests should be on samples that are representative of the production, should be appropriate for the parameters required, and be carried out under proper supervision. Reference samples and... 

The emulsifying capacity is represented by the volume of oil (cm3) that is emulsified in a model system by 1 g of protein when oil is added continuously to a stirred aliquot of solution or dispersion of the tested protein. It is determined by measuring the quantity of oil at the point of phase inversion. The latter can be detected by a change in color, viscosity, or electrical resistance of the emulsion, or the power taken by the stirrer engine. The emulsifying capacity decreases with an increasing concentration of protein in the aqueous volume. It is affected by the parameters of emulsification, depending on the equipment, as well as by the properties of the oil. 

Additionally, some parameters, such as sensitivity, are influenced by electrical and mechanical effects. This means that designing the sensor has to include not only the sensor s geometry, but also the design of tests that can distinguish between electrical (e.g., capacitance) and mechanical (e.g., stress) properties. Thus, designing for testing is an important issue. 

Fig. 5.10.2 Test concept for determination of the quadrature number of a rotating disc gyro. The section on the left lists all electrically measured properties. Sections to the right show the sequence of models and simulations employed to extract sensor parameters, including the quadrature number...

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