Behaviour of HCH (1,2,3,4,5,6-hexachlorocyclohexane) residue in the aquatic environment

The monthly variation in HCH (1,2,3,4,5,6-hexachlorocyclohexane) residue levels in surface waters was investigated. The logarithms of monthly HCH concentrations described the wave, and the equation of the wave was calculated by the least squares method. The waves indicated maximum concentrations in summer and minimum concentrations in winter at each sampling site. The maximum concentration of HCH in each year decreased gradually. The amplitude of the wave at the reservoir was the smallest among sampling sites. The slope of the wave at the downstream sampling site was smaller than that at the upper stream. Maximum concentration of total HCH at each sampling site in 1985 is estimated from the equations; the concentrations at the upper streams will be about a thousandth or a hundredth of that at the downstreams. Also, the equations for β-and γ-HCH were calculated, and indicated that β-HCH was more persistent than γ-HCH in surface water. The ratio of β-HCH to total HCH in surface water is estimated to be about 60% in 1985.     

Structural,electrical and optical properties of r.f.-magnetron-sputtered SnO2:Sb film

The effects of gas composition, pressure and substrate temperature on the properties of relatively thick (0.2–0.8 μm) SnO₂ films deposited onto fused quartz substrates by r.f. magnetron sputtering are reported. The lowest resistivity of about 2 × 10^?3ωcm was attained for high rate deposition conditions of about $\text{1000}\text{A}\text{?}\text{min}{}^{\mathrm{?1}}$ on substrates at a temperature of 400°C in an atmosphere of 10% O₂. This value corresponds to a carrier density of 3 × 10²⁰cm^?3 and a mobility of 10 cm²V^?1s^?1. The crystal structure was found to be sensitive to all the above parameters. Low resistivity films showed a highly preferred orientation of (101) parallel to the substrate.     

Ozone treatment of water-soluble polymers. III. Ozone degradation of polyacrylamide in water

Polyacrylamide (MW 350,000) was ozonized at pH 2 and pH 10 buffer solution. There was little ozonization at pH 2, but at pH 10 the COD and the viscosity of the solution decreased upon ozonization, and a linear relationship existed between the ozone consumed and the number of breaks calculated from the viscosity. This relationship apparently indicated that 45 molecules ozone were consumed for one cleavage of the polymer chain. Such random cleavage was confirmed also by the observation of molecular weight distribution by means of gel filtration chromatography. The amide group decreased scarcely by the ozonization, while a small amount of aldehyde was observed in the ozonized solution. No remarkable change was observed in the IR spectra of the ozonized sample, except for a weak absorption band at 1725 cm^?1 which arose from the carbonyl of aldehyde or ketone. Although no variation was observed in the ¹³C NMR spectra either, a strong absorption peak at 266 nm appeared in the UV spectra of the ozonized solution and increased with the ozonization time. This phenomenon was presumed to be due to the formation of a certain ring structure between the amide group and the small amount of ketone produced in the main chain. However, the details of the ozonization mechanism could not be ascertained.     

TDMA Site Diversity Switching Experiments with Japanese CS

A site diversity switching experiment system for satellite earth links adopting PCM/PSK/TDMA is introduced. Results of downlink switching experiments using CS (30/20 GHz) are presented. Investigations of measuring time of signal quality for minimizing the diversity. switching error are made in point of Allan variance of bit error rate (BER) and of the defined switching error rate.     

Photo-induced electron transfer of a chlorophyll—liquid crystal electrode to water

A platinum plate was coated with a thin layer of chlorophyll and liquid crystal in order to make it photo-excitable. The chlorophyll—liquid crystal electrode immersed in water was found to shift its electrode potential to a more positive value on light irradiation. Furthermore light irradiation increased cathodic current. Liquid crystals such as N-(p-methoxybenzylidene)-p′-butylaniline markedly enhanced a photo-response in electrode potential and current. A prominent photo-response of the electrode appeared in an acidic solution around pH 4. A possibility of a direct electron transfer from a photo-excited chlorophyll—liquid crystal electrode to water, ie, photo-decomposition of water, is suggested.