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The height limit gantry of urban viaducts has being playing an important role in the information management and traffic dispatch. However, it also limits special vehicles. This paper discusses and analyses three kinds of short-range wireless communication methods in detail (including ZigBee, Bluetooth and Radio Frequency Identification (RFID)), establishes a transmission distance estimation model, analyses some information interferences of vehicles with different roads, designs to an implement quickly channel connection and an identify information for main slave communication modules. The communication slave module is assembled in special vehicles, which is connected with the communication main module in the height limit gantry. A main controller completes the feature recognition and the rise and fall of height limit gantry. The device improves the efficiency of emergency vehicles, with the rapidity, reliability and practicality.

The poly(ethylene terephthalate)-PET is widely used in dielectric insulation, so the study on its luminescence characters is valuable. The Photoluminescence-PL intensity and spectra of PET films were detected by the home-made set-up. Experiment shows: The PL intensity with exponential decay along with the time. There are emitting peaks about 300–400nm, 500–600nm and nearby 700nm in the PL accumulative spectra, and the peak region nearby 700nm is a little higher. The absorption spectra were tested by TU-1901 double beam UV-Vis spectrophotometer. The calculation shows that energy gap of PET films is about 3.96eV according to the absorption edge of the spectra. The results we obtained from the PL measurement indicate that this method will contribute to understanding the trap distribution and luminescent micro-mechanism of Insulation Polymers.

Tested electroluminescence (EL) of both original and inorganic nano particle doped polyimide films under dc field by experimental set-up made-home. The results showed that the luminescence of both polyimide films increased along with the electric field. Their pre-breakdown fields obtained by measuring EL were much similar. The pre-breakdown field of nano particle doped polyimide film was higher than the original's, But, under the same field, the EL of the former was less than the latter's. The EL of nano particle doped polyimide films had peak value whose width was about 60s after 430s, and the EL was higher than initial value throughout the descending region.

This paper obtains the discharge graph and fractal dimension by calculation of electric field distribution in a system of needle-plate electrodes by the finite element method, and in consideration of the stochastic dependence discharge growth probability on the local electric field. The results agree with those of Barclay (1990), and confirm that as /spl eta/ becomes larger, the discharge graph becomes more linear.