Zinc Oxide nanoparticles' thick film sensors doped with tungsten,has been developed and its response towards alcohol has been measured. The nanoparticles were synthesised by the chemical combustion technique and characterised by XRD, FESEM and EDS. It was established that the nanoparticles exist in a hexagonal system in a primitive lattice with no other impurities. A study on the sensing performance of the sensors hence prepared to the three primary alcohols has been carried out with the help of a new index which we call rate of response (sensitivity/sensing time). The sensors exhibit rate of responses as high as 22%/s with a sensitivity of around 80% with good selectivity and reproducibility.
Volatile methyl compounds are formed by the majority of elements standing up to six places before a rare gas, so that as a class they represent all groups and periods of the Periodic System with the exception of Group I. Accordingly, the volatile methyls provide a particularly suitable class of compounds for a comparative study of the covalent bonds which the metals and non-metals concerned form with carbon; and this study in turn throws light on the magnitudes of the internal excitation energies possessed by these elements when engaged in covalent bonding. Former approaches to this problem have been almost entirely theoretical. For convenience, the term" metal-carbon bond" will be used throughout this paper to denote all bonds of the type stated, whether the element linked to carbon is a metal or not.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.