Ammonia, electronic devices

Apart from hydrocarbons and gasoline, other possible fuels include hydrazine, ammonia, and methanol, to mention just a few. Fuel cells powered by direct conversion of liquid methanol have promise as a possible alternative to batteries for portable electronic devices (cf. below). These considerations already indicate that fuel cells are not stand-alone devices, but need many supporting accessories, which consume current produced by the cell and thus lower the overall electrical efficiencies. The schematic of the major components of a so-called fuel cell system is shown in Figure 22. Fuel cell systems require sophisticated control systems to provide accurate metering of the fuel and air and to exhaust the reaction products. Important operational factors include stoichiometry of the reactants, pressure balance across the separator membrane, and freedom from impurities that shorten life (i.e., poison the catalysts). Depending on the application, a power-conditioning unit may be added to convert the direct current from the fuel cell into alternating current. 

Aygun S, Cann D (2005) Hydrogen sensitivity of doped CuO/ZnO heterocontact. Sens Actuators B 106 837-842 Badlani M, Wachs IE (2001) Methanol a smart chemical probe molecule. Catal Lett 75(3-4) 137-149 Baek K-K, TuUer HE (1993) Electronic characterization of ZnO/CuO heterojunctions. Sens Actuators B 13 238-240 Bahu M, Kumar K, Bahu T (2012) CuO-ZnO semiconductor gas sensors for ammonia at room temperatures. J Electron Devices 14 1137-1141... 

Natural gas, which is mostly methane, is widely used as a fuel. In the chemical industry, methane is used heavily as a raw material for making important products that include acetylene, ammonia, ethanol, and methanol its chlorination also yields carbon tetrachloride, chloroform, methyl chloride, and methylene chloride. It is used to produce carbon black for use in the manufacture of rubber products and printing inks. The burning of high-purity methane is used to make carbon black of special quality for electronic devices. Natural gas has seen limited use as a motor fuel handled as a compressed gas in high pressure cylinders or liquid dewars. 

The Co(III)—C bond in the natural coenzymes is resistant to cleavage in protic solvents. However, the bond length [20] is similar to that in models. Indeed, there appear to be no special corrin ring electronic properties necessary for such water-stable Co—C bonds even Co(III)—CH3 compounds with classical ligands such as ammonia or ethylenediamine have now been discovered [21], Although such non-Bi2-related systems are outside the scope of this review, I believe that the main reason that few such compounds are known lies in the paucity of synthetic routes. Since the Co—C bond, once formed, is relatively inert, such compounds could be used for multiple types of applications such as in molecular assemblies or devices [22], The natural compounds and some models are photosensitive, however [23]. It is this photosensitivity that delayed the discovery of the coenzymes, leading instead to the isolation and characterization of the vitamin [1]. 

However, in both the yeast and the E. coli systems, the stoichiometries for NADPH S and SOj -rS - are 3 1 and 1 1, respectively. These results and the inability to detect 2-electron- and 4-electron-reduced intermediates in these systems have suggested that such intermediates, if present at all, must be firmly held on the surface of the enzyme. It has further been suggested that the presence of multiple flavins and hemes in the enzyme might be a device for achieving a rapid six-electron reduction of sulfite without the release of intermediates (414)- This situation is analogous to the four-electron reduction of 0, to 2H,0 by cytochrome oxidase and the six-electron reduction of nitrite to ammonia by various assimilatory nitrite reductases. However, unlike cytochrome oxidase,... 

Silicon nitride (Si3N4) is a major industrial material which is produced extensively by CVD for electronic and structural applications. It is an excellent electrical insulator and diffusion barrier (to sodium and water vapor) and has replaced CVD oxides in many semiconductor devices.l l Silicon nitride coatings are produced by the reaction of silicon tetrachloride (SiCl4) with ammonia ... 

The effect of humidity on metallophthalocyanine gas sensors has been studied for a donor gas (e.g. ammonia) and an acceptor gas (e.g. nitrogen dioxide). It has been found that water vapour acts as an effective electron donor on phthalocyanine surfaces. The presence of water vapour enhances the devices sensitivity but reduces the response and recovery times. The donor... 

---