Complex electrical conductivity

Eiectromagnetic (eddy currant) Complex electrical conductivity, complex magnetic permeability Density, reinforcement ratio, porosity, damage accumulation, geometry, structure, flaw size... 

R. P. Shibaeva, V. F. Kaminskii, M. A. Simonov, E. B. Yagubskii and E. E. Kostiosenko, Structure of electrically conducting complexes from radical cations. Xni. Radical cation salt of perylene with platinum (II) bis (dicyanoethylene-l,2-dithiolate), (C20H12) [Pt(S4C4(CN)4], Kristallografia 30, 488 (1985). 

As an example of RBS applied to a polymer system, figure 3.22 shows the spectrum obtained from a sample of the conjugated polymer poly(phenylene, vinylene) after exposure to arsenic pentafluoride vapour (Masse et al. 1990). This dopant diffuses into the polymer and reacts with it to form an electrically conducting complex and RBS is well suited to following the kinetics of the doping process by providing concentration-depth profiles of the elemental components of the dopant as a function of time. The peaks in the spectrum... 

A number of molecular complexes and CT salts have been isolated in crystalline form, and the charge-O ansfer bands evaluated in the solid state by transmission or reflectance spectroscopy [159]. It is generally found that the CT transition is strongly polarized along one of the crystal axes. For strong, electrically conducting complexes, the axis of polarization coincides with the one- or two-dimensional conductivity of the crystals [160]. 

At present, the major focus of the researchers is on the nanocomposite materials based on the nanoparticles of metals and their compounds stabilized within a polymeric dielectric matrix [1-4]. The dielectric and optical properties of these materials have been demonstrated to be highly dependent on the size, structure, and concentration of the nanopartides, as well as on the type of polymeric matrix [5-8]. These have shown the possibility of the purposeful change of parameters of the nanocomposite materials such as electrical conductivity, complex permittivity, refraction coefficient, and so on. It is believed that these materials would demonstrate low acoustic impedance because they are based on the polymeric matrix [9]. At that, the impedance value should be varied within certain limits by adjusting the parameters of the embedded nanopartides. All of these would allow one to use these materials for low disturbing substrates in various devices based on the waves in thin piezoelectric plates [10]. 

Other methods attempt to probe the stmcture of the foam indirectly, without directly imaging it. Eor example, since the Hquid portion of the foam typically contains electrolytes, it conducts electrical current, and much work has been done on relating the electrical conductivity of a foam to its Hquid content, both experimentally (15) and theoretically (16). The value of the conductivity depends in a very complex fashion on not only the Hquid content and its distribution between films and borders, but the geometrical stmcture of the bubble packing arrangement. Thus electrical measurements offer only a rather cmde probe of the gas Hquid ratio, a quantity that can be accurately estimated from the foam s mass density. 

In 1932 a class of complexes consisting of ethers, sodium, and polycycHc hydrocarbons was discovered (19). Sodium reacts with naphthalene in dimethyl ether as solvent to form a soluble, dark-green, reactive complex. The solution is electrically conductive. The reaction has been described as follows... 

Practical appHcations have been reported for PVP/ceUulosics (108,119,120) and PVP/polysulfones (121,122) in membrane separation technology, eg, in the manufacture of dialysis membranes. Electrically conductive polymers of polyaruline are rendered more soluble and hence easier to process by complexation with PVP (123). Addition of small amounts of PVP to nylon 66 and 610 causes significant morphological changes, resulting in fewer but more regular spherulites (124). 

Table 2 shows the present state-of-the-art for the electrical conductivity of doped conjugated polymers. The magnitude of the electrical conductivity in polymers is a complex property determined by many stmctural aspects of the system. These include main-chain stmcture and TT-ovedap, molecular... 

The determination of precise physical properties for elemental boron is bedevilled by the twin difficulties of complex polymorphism and contamination by irremovable impurities. Boron is an extremely hard refractory solid of high mp, low density and very low electrical conductivity. Crystalline forms are dark red in transmitted light and powdered forms are black. The most stable ()3-rhombohedral) modification has mp 2092°C (exceeded only by C among the non-metals), bp 4000°C, d 2.35 gcm (a-rhombohedral form 2.45gcm ), A77sublimation 570kJ per mol of B, electrical conductivity at room temperature 1.5 x 10 ohm cm- . 

From the obtained trajectories the following structural and electronic properties were extracted (i) structure factors, (ii) stability of Sn complexes, in particular, the Zintl anions, and (iii) the electrical conductivities - which yield answers to the questions mentioned in the first paragraph. 

Electrical conductivities of polybromide complexes containing MEP and MEM were studied by Arbes [73]. Pure MEPBr complexes always show higher conductivity than those containing only... 

Above a critical hller concentration, the percolation threshold, the properties of the reinforced rubber material change drastically, because a hller-hUer network is estabhshed. This results, for example, in an overproportional increase of electrical conductivity of a carbon black-hUed compound. The continuous disruption and restorahon of this hller network upon deformation is well visible in the so-called Payne effect [20,21], as represented in Figure 29.5. It illustrates the strain-dependence of the modulus and the strain-independent contributions to the complex shear or tensUe moduli for carbon black-hlled compounds and sUica-hUed compounds. 

PCBs were hrst produced commercially around 1930. The commercial products are complex mixtures of congeners, generated by the chlorination of biphenyl. Most of them are very stable viscous liquids, of low electrical conductivity and low vapor pressure. Their principal commercial applications have been... 

Lithium triflate was the most used salt and the temperature dependence of the electrical conductivity of a series of (LiS03CF3)x/MEEP complexes with a ratio metal cation/MEEP repeat unit 0.125[Pg.203]

For the support material of electro-catalysts in PEMFC, Vulcan XC72(Cabot) has been widely used. This carbon black has been successfully employed for the fuel cell applications for its good electric conductivity and high chemical/physical stability. But higher amount of active metals in the electro-catalysts, compared to the general purpose catalysts, make it difficult to control the metal size and the degree of distribution. This is mainly because of the restricted surface area of Vulcan XC72 carbon black. Thus complex and careM processes are necessary to get well dispersed fine active metal particles[4,5]. 

Aluminum metal is produced from aluminum oxide by electrolysis using the Hall-Heroult process, whose story is detailed in our Chemical Milestones Box. The melting point of AI2 O3 is too high (2015 °C) and its electrical conductivity too low to make direct electrolysis commercially viable. Instead, AI2 O3 is mixed with cryolite (Na3 AlFfi) containing about 10% CaF2. This mixture has a melting point of 1000 °C, still a high temperature but not prohibitively so. Aluminum forms several complex ions with fluoride and oxide, so the molten mixture... 

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