For the determination of the low concentration of 222Rn in sea water, an improved 222Rn extraction and counting system was developed. The 222Rn in a 20 l sample bottle was extracted from sea water with helium and collected in a charcoal trap cooled with dry ice and alcohol. The 222Rn extraction is accomplished by two circulation loops in a closed system : one is the rapid extraction loop of 222Rn from sample water by violent gas bubbling and strong agitation, and the other is the adsorption loop of 222Rn with a cooled charcoal trap. Successively, the 222Rn was desorbed from the trap by heating and transferred to a scintilla-tion cell coated with ZnS(Ag). Following these procedures one can process a sample in 100 min with an overall efficiency (extraction-transfer-counting) of 57%. Some results of 222Rn and 226Ra concentrations in coastal sea water are reported.
An accurate calibration method taking account of imperfections in optical components is described for rotating analyzer ellipsometers. Precision and accuracy are discussed in detail for both stationary and time-varying ellipsometric parameters, Ψ and Δ, in rotating analyzer ellipsometry. An application of the present method to the study of anodic film growth on BizTez is shown.
Basic materials of the humidity sensitive film of the present humidity sensor are heat-treated mixtures of silicone polymers and metal oxides. Upon heating, the organic groups in silicone polymers are decomposed. New composite materials are thus formed, which are based on metal oxides bound by the decomposition residue. One of the main constituents is amorphous SiO2. The present sensor has good humidity sensitivity characteristics which vary with heat-treated temperatures. Hardly any surface hydroxyl group is formed on the humidity sensitive element of the present sensor (heat-treated at 500°C). Therefore, the present sensor is more reliable than the conventional ceramic humidity sensors with regard to the time dependence of humidity-resistance characteristics. Also, the present sensor can be produced by heat treatment at lower temperatures in comparison with the conventional ceramic sensors.
The emitting color changed from green to red with increasing frequency in an In2O3: SnO2-Y2O3-ZnS: ErF3, YbF3-Y2O3-Al structure thin film electroluminescent device. The energy transfer process from Yb3+ ion to Er3+ ion and emission transition processes in electroluminescence are discussed.