Electrode-based electrical resistivity

It is used in certain nickel-based alloys, such as the "Hastelloys(R)" which are heat-resistant and corrosion-resistant to chemical solutions. Molybdenum oxidizes at elevated temperatures. The metal has found recent application as electrodes for electrically heated glass furnaces and foreheaths. The metal is also used in nuclear energy applications and for missile and aircraft parts. Molybdenum is valuable as a catalyst in the refining of petroleum. It has found applications as a filament material in electronic and electrical applications. Molybdenum is an... 

A well-known fact of fundamental solution science is that the presence of ions in any solution gives the solution a low electrical resistance and the ability to conduct an electrical current. The absence of ions means that the solution would not be conductive. Thus, solutions of ionic compounds and acids, especially strong acids, have a low electrical resistance and are conductive. This means that if a pair of conductive surfaces are immersed into the solution and connected to an electrical power source, such as a simple battery, a current can be detected flowing in the circuit. Alternatively, if the resistance of the solution between the electrodes were measured (with an ohmmeter), it would be low. Conductivity cells based on this simple design are in common use in nonchromatography applications to determine the quality of deionized water, for example. Deionized water should have no ions dissolved in it and thus should have a very low conductivity. The conductivity detector is based on this simple apparatus. 

Due to the porous structure of the electrodes, the electrical and ionic conductivities are different from those of the dense materials, and are strongly dependent on the porosity. Pores, in fact, can be considered as having infinite resistivity, thus they reduce the overall conductivity. For Ni-based anodes, assuming nickel particles as spherical, Zhao and Virkar [36] proposed the following formula ... 

To ensure a sufficient electronic and thermal conductivity of the positive electrode during the charge and discharge process, conductive additives are required in the positive, transition metal oxide-based electrode.3133 Compared to metal powders as potential conductivity enhancer, carbon materials combine high electronic and thermal conductivity with low weight, low costs, relatively high chemical inertness, and nontoxicity. Conductive carbons optimize the electrical resistivity of the positive electrode mass but are not involved in the electrochemical redox process which delivers the... 

The solid oxide fue( cell (SOFC) have been under development during several decades since it was discovered by Baur and Preis in 1937, In order to commercialise this high temperature (600 - 1000°C) fuel cell it is necessary to reduce the costs of fabrication and operation. Here ceria-based materials are of potential interest because doped ceria may help to decrease the internal electrical resistance of the SOFC by reducing the polarisation resistance in both the fuel and the air electrode. Further, the possibility of using less pre-treatment and lower water (steam) partial pressure in the natural gas feed due to lower susceptibility to coke formation on ceria containing fuel electrodes (anodes) may simplify the balance of plant of the fuel cell system, and fmally it is anticipated that ceria based anodes will be less sensitive to poising from fuel impurities such as sulphur. 

Electric resistivity. The electric resistance measurement is the same as discussed below under volume resistivity, to which this measurement is temporary adapted. For flexible materials, special electrode systems are developed to clamp sample and electric wires. The measuring equipment is based on a Wheatstone bridge circuit. The conductivity of metal powder-containing epoxy was measured in special dies equipped with built-in brass electrodes inserted to the die. The material was cured in the die to assure good contact with electrodes. Special sample holders and clamping devices are used for precise determination of rubber compounds containing carbon black. ... 

Special Property Membranes. In the literature, there are numerous methods reported for the preparation of ion-exchange membranes with special properties,87-89 for instance, for use as battery separators, ion-selective electrodes, or in the chlor-alkali process. Especially membranes recently developed for the chlor-alkali industry are of commercial significance. These membranes are based on polytetrafluoroethylene and carry sulfone groups in the bulk of the membrane phase and carboxyl-groups on the surface as the charged moiety. They combine good chemical stability with high selectivity and low electric resistance. 

Most of the position-sensitive semiconductor detectors determine the position of the incident particle by employing the method of resistive-charge division To illustrate the method, consider the detector in Fig. 13.25. The detector is a reverse-biased p-n junction with electrodes on both front and back. The front electrode with considerable resistivity has two electrical contacts a distance L apart. The back electrode has low resistivity and provides a good electrical contact to the base material. When a particle enters the detector, electrons and holes are created that move under the influence of the electric field. If the resistivity of the front electrode is homogeneous, and charge-sensitive low-impedance amplifiers are used, the charge collected at one of the two contacts of the front electrode is proportional to the distance between the point of impact... 

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