No abstract

Characteristics of polycrystalline silicon thin-film transistors (TFT) with source/drain extensions induced by a bottom sub-gate were explored, high on/off current ratio up to 10 7 could be achieved for both n-and p-channel devices. Nevertheless, the performance is significantly degraded by a marked increase of off-state leakage current when the channel length is scaled below 1 m. Moreover, a hump in the subthreshold current-voltage regime is observed. After careful analysis, it is found that the leakage current is strongly dependent on the field strength and is not a thermally activated process. A leakage path along the bottom interface of the poly-Si channel layer is proposed to explain these results.

In this thesis, stable nanoMgO particles were prepared by precipitation process, using analytical pure MgCl2·6H2O and NH3·H2O as the raw materials, which MgCl2 as the source of magnesium and NH3·H2O as the precipitating agent. The dispersant of PAAS and SHMP in appropriate dosage was also needed. The nanoMgO particles were characterized by using techniques such as Infrared Spectroscopy, Absorbance Determination, Scanning Electron Microscopy and tested by Laser Particle Size Analyzer. The nanoMgO finishing agent is prepared in the condition of ultrasonic oscillation by optimized processes which involve the choosing of appropriate dispersant. Finally, the good UV protection and antibacterial silk fabrics was obtained through functional finishing by impregnating process on silk fabrics under treated by peregal-O. This work lays a foundation for the research and application of nanoscale finishing agent preparation with the low cost. The results showed that the stability of prepared nanoMgO particles is considerable, the durability of the finished fabrics is satisfactoried.

For the time varying of signals, empirical mode decomposition (EMD) is occupied to modulate signals; auto-regressive moving average (ARMA) of higher accuracy is used to establish model for the signal principal components; then parametric bi-cepstrum estimation is implemented and fault feature is extracted. The test results about gearbox of overhead traveling crane indicate: the feature quefrency can be obtained through method of EMD and ARMA model parametric bi-cepstrum estimation.It is a kind of effective fault diagnosis and stability evaluation method.

Microwave dielectric ceramics Y(Nb0.5Ti0.5)2O6, SmTiNbO6, LaTiNbO6 have been prepared by conventional solid state method. The single phase of these three kind of samples are obtained at 1350°C, 1340°C and 1280°C, respectively. SmTiNbO6 has positive τf (50.05ppm/°C) and Y(Nb0.5Ti0.5)2O6 (-64.27ppm/°C), LaTiNbO6 have negative τf (-67.39ppm/°C). Dielectric constant, quality factor and temperature coefficient of resonant frequency increase with the increased sintering temperature firstly and then decrease which is due to the lower density. Dense Y(Nb0.5Ti0.5)2O6, SmTiNbO6 ceramics are obtained at the proper sintering temperature but for LaTiNbO6 ceramics there are many pores on the grain surface.