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Carbon blacks are widely used as electrocatalyst supports in polymer electrolyte fuel cells (PEFCs), and the corrosion of carbon blacks has a severe impact on the long-term durability of PEFCs. The steam etching approach was used to investigate the corrosion of the low-surface area XC72 carbon black and the high-surface area black pearl 2000 carbon black under different conditions. The weight loss of the XC72 and the black pearl 2000 when etched at 800 degrees C for 3 h is 28.43% and 54.82%, respectively. TEM results show that the corrosion of the XC72 begins from the center of the particle, while the corrosion on the black pearl 2000 starts on the particle surface. XRD results show that the 0 0 2 and 10 peaks of the XC72-based samples are initially sharp, but then broaden during the corrosion process. For black pearl 2000-based samples, the 0 0 2 and 10 peaks all became broader during the corrosion process. The results provide guidelines for modifying carbon black as catalyst supports to achieve a higher durability.

We surveyed 128 preschool children in a lead-polluted area in Shanghai to study the relationship between blood lead level and neuropsychological functions, assessed by age-appropriate psychological tests. The geometric means of blood lead level was 21.7 + -10.8 micrograms/dl. Of 47 children aged below 30 months, there was no significant difference in BSID indices between the high and low lead subjects, although the high lead children tended to have poorer development scores than the low lead ones. On the other hand, of 81 children older than 46 months, the WPPSI IQ scores showed highly significant negative correlation with blood lead level. Step-wise regression and multiple analysis of covariance techniques were employed to find out and control the confounding factors. Even when 21 non-lead variables were considered, the IQ difference between high and low lead groups remained statistically significant. We concluded that the children, especially those older than 46 months, in the area investigated, did suffer from lead toxicity causing impairment in intelligence development. We support the view that marginally higher lead level in children should be taken seriously.