No abstract

Concentration of 4 heavy metals (Cu, Pb, Zn, Cd) and petroleum hydrocarbon in the surface sediments collected from Chenglingji, Dongting Lake, were quantitatively analyzed. Distribution characteristics and possible sources of the heavy metals and petroleum hydrocarbon were discussed. Methods of single-factor index and geoaccumulation index were adopted to evaluate the potential ecological risks of heavy metal. The results showed that Cd was seriously polluted and in a strong ecological risk level; Cu, Pb and Zn pollution was mild in Chenglingji Port, Dongting Lake. Petroleum hydrocarbon content of nearshore sediment was low exclude of area near Chenglingji Port, which significantly exceeded the standard value. And the content of petroleum hydrocarbon decreased with the distance far away from the harbor.

This paper presents a control strategy of torque distribution for electric vehicles with axles separately driven. With two motors driving the front and rear axle separately, the torque distribution between axles can be easily achieved. To obtain good traction performance and stability of the electric vehicle, three control modes appropriate for different driving conditions are adopted: the routine control of equal distribution; the distribution based on Sliding Mode Control (SMC) to minimize wheel slip difference between axles; axles separately antiskid control based on SMC. With MATLAB/SimDriveline software, a forward vehicle simulation model was set up. The simulation results show that the torque distribution control strategy of three control modes can maintain the wheel slip in a reasonable range regardless of driving conditions, improving both vehicle traction ability and stability.

In order to realize the application of the underground wireless monitoring network, in view of the characteristics of the underground wireless monitoring, a kind of multi jump wireless routing protocol based address priority and star-bus topology is designed in this paper. After the analysis of the mine wireless transmission process model and data broadcast problem, considering the technologies of direction control, second localization, the anti-interference, network survival period and so, a method of adding the protocol address and the uplink and downlink flag is proproesd to solve these probles above. Simulation results show that, this protocol can be successfully completed the wireless datatransmission in the underground laneway environment.