We have measured the decay of NMR multiple quantum coherence intensities both under the internal dipolar Hamiltonian as well as when this interaction is effectively averaged to zero, in the cubic calcium fluoride CaF2 spin system and the pseudo-one-dimensional system of fluoroapatite. In calcium fluoride the decay rates depend both on the number of correlated spins in the cluster, as well as on...

The well being of human depends on quality of drinking water. Consumption of water containing excess fluoride over a long period of time results in fluorosis. Ramaraju et al., (2000). Investigations of Wood, (1974) showed that, the intake of fluoride is permissible upto 0.5-1.0 mg/L which is beneficial to human health. The maximum allowable concentration for fluoride in drinking water in Indian...

A lthough recent data suggest that the incidence rate of dental caries has begun to decline dramatically in developed nations' Canadians still have a moderate to high rate of the disease.2 Fluoridation of communal water supplies is the most cost-effective measure to prevent dental caries; it reduces dental decay by 30% to 60% yet costs only about 15¢ per person per year.3 Unfortunately, only ab...

Nanopowders of strontium fluoroapatite Sr5(PO4)3F (SFAP) were synthesized using a co-precipitation method with different starting compounds. Based on the data XRD, BET and SEM measurements, nitrate-derived powders chosen as least agglomerated. The SFAP hot pressed at 1000 °C to ceramic samples transmittance up 82% in mid-IR region. designed approach was adopted prepare 2 mol % Er-doped ceramics...