Road-deposited sediment (RDS) is an important environmental medium that affects the characteristics of heavy metals in stormwater runoff. 62 RDS samples were collected from four different land use types (commercial, residential, intense traffic and riverside park) in the Zhenjiang city of China. The samples were analysed for concentrations of five metals (Zn, Pb, Cu, Cr and Ni). The maximum mean concentrations of Zn, Pb, Cu, Cr and Ni from different land use types were 686, 589, 158, 129 and 125 mg/kg, respectively. The intense traffic area displayed the highest metal concentrations, whilst Zn, Cr, Ni and Cu did not show any discernible variations among the other three areas. Seven particle sizes were analysed separately for the heavy metal concentrations. In all studied areas, particles<63 microm have the highest metal concentrations: 926-1,188 mg/kg of Zn, 270-928 mg/kg of Pb, 150-220 mg/kg of Cu, 99-172 mg/kg of Cr and 96-147 mg/kg of Ni. The fine particle fraction (<63 microm) of the samples accounted for about 25-60% of the total metal loading; in contrast, the coarsest fraction (1,000-2,000 microm) only contributed 1-5%. The calculated ecological risk index shows that considerably high potential risks exist in the intense traffic area particularly due to high concentrations of Pb. These findings provide invaluable information for the development of appropriate management strategies to decrease nonpoint source contamination loading to the water environment in urban areas.

Thin films of oriented island-like crystallites of L1 0 FePt separated by amorphous (a-)Al 2 O 3 were fabricated. The process took advantage of the overgrowth of ␣-Fe on Pt ''seed'' particles epitaxially grown on ͑100͒ NaCl and MgO substrates and the ordering reaction between Fe and Pt upon annealing at temperatures higher than 500 °C. The coercivities of the annealed ͑600 °C for 6 h͒ a-Al 2 O 3 /Fe͑1 nm͒/Pt ͑1.5 nm͒ films on both the NaCl ͑100͒ and MgO ͑100͒ substrates are higher than 3.3 kOe. Transmission electron microscopy observation showed that the film consisted of oriented L1 0 FePt island-like crystals with an average size of 12 nm and a separation of 4 nm. It was found that any one of the three ͗100͘ axes of the fcc Pt parent particles could act as the tetragonal c axis of the L1 0 FePt superstructure and all three-variant ordered crystalline domains of the tetragonal L1 0 phase could exist in the small 10-nm-size FePt crystallites. The high magnetic coercivity of the film, with well-separated FePt particles, can be attributed to the ordering (L1 0 ) as well as the oriented nature of the FePt crystallites.

The crystallization behavior of a-Si:H/Ag/a-Si:H sandwich films has been studied in detail. Fractals of Si caused by metal enhanced crystallization appear after annealing at 350–600 °C. The fractal dimension decreases (the Si fractals become more open) with the increasing annealing temperature. The number density of fractals increases at 350–450 °C and turns to decrease at 500–600 °C. The average fractal size increases from 350 to 550 °C and shows a decreasing tendency at 600 °C. The formation of fractals can be explained by a random successive nucleation and growth model. The x-ray energy dispersive spectroscopy (EDS) microanalysis indicates that although there is lateral interdiffusion of Ag and Si atoms, the thicknesses of the fractal region and the matrix remain nearly the same. At the same time, EDS shows that there are also Ag aggregates extending out of the films. It is suggested that besides the preferred nucleation at the Ag/Si interface the break of Si—H bonds may also stimulate the crystallization of a-Si:H so that the crystallization temperature of an a-Si:H/Ag system is much lower than that of an a-Si/Ag system.

An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60-80%, <250 microm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 microm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-microm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 microm for TN).