The thickness effect of solid dielectrics means the relation between the electric breakdown strength (EBD) and the dielectric thickness (d). By reviewing different types of expressions of EBD on d, it is found that the minus power relation (EBD = E1d−a) is supported by plenty of experimental results. The physical mechanism responsible for the minus power relation of the thickness effect is reviewed and improved. In addition, it is found that the physical meaning of the power exponent a is approximately the relative standard error of the EBD distributions in perspective of the Weibull distribution. In the end, the factors influencing the power exponent a are discussed.

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poly[(2-methoxy,5-octoxy)1,4- phenylenevinylene-carbon nanotube composites (MOPPV-CNTs) were synthetized by In-situ polymerization in the paper. The molecular structure and surface morphology of the nanocomposites were characterized by the TEM. The TEM results showed that the MOPPV coated on the CNTs forming Core-shell nanowires structure composite. The wavelength of UV-absorption spectra of the composites exhibited a blue shift caused by the functionalized MWCNTs. the energy gap of the composites were increased. The band structures of the composite were determined by using cyclic voltammetry, the result shown that the HOMO energy and the LUMO energy increased with the concentration of CNTS. The increase of LUMO energy would benefit for balance of the carries injection when the composites used in the optoelectronic devices.

A testing circuit of probe is designed to research the electrical properties of the probe under different loading frequencies. Sinusoidal signals of different frequencies are produced by Tektronix AFG3102 signal generator, and DSOX2022A Oscilloscope is used to measure the probe voltage,constant resistance voltage and the source voltage, so the phase between the probe voltage and constant resistance voltage can be calculated. Assumed the constant resistance is a pure resistance. Since the circuit is connected in series, so the phase between the probe voltage and the probe current can be calculated. The result reveals that the probe shows resistive when the phase between the probe voltage and the probe current is 0 ° within 200 KHz frequency. Beyond 200 KHz the phase between the probe voltage and the probe current increases to 60 ° and then declines to a steady value 40°, which shows that the probe is inductive.

Using the same bend waveguide with two different E-field polarization directions, the breakdown phenomena in a curved waveguide with different power capacities were studied. For the case of lower power capacity, breakdown happens at the curved arm; with increasing incident power, the reflected peak amplitude increases, the breakdown delay time becomes shorter, and the reflected pulse gradually overlaps with the incident one, forming a slower falling edge at the end of incident pulse. For the case of higher power capacity, discharge may occur at the connected flanges without the choke shot. Using the four-frame intensified-charged-coupled device diagnosing the nanosecond light emission in each of the vertical and horizontal polarization cases, the intensities in both of the surface layer and the space beyond were found to first become bright during the microwave pulse, and then get dark after the pulse. The multiple bright spots on the wall illustrate the nonuniform plasma development and local high-density plasma at the microprotrusions with field enhancement, triggering the intense high-field emission or explosive emission.Index Terms-High-power microwave, vacuum breakdown, waveguide discharge.