Superlattice-like (SLL) SnSb 4 /Ga 3 Sb 7 (SS/GS) thin films were investigated through in-situ film resistance measurement. The optical band gap was derived from the transmittance spectra by using a UV-visible-NIR (ultraviolet-visible-near infrared) spectrophotometer. Transmission electron microscopy was used to observe the micro-structure before and after annealing. Phase change memory cells based on the SLL [SS(3 nm)/GS(4.5 nm)] 7 thin films were fabricated to test and verify the operation consumption and switching endurance. The scanning thermal microscopy was used to probe the nanoscale thermal property. V C 2015 AIP Publishing LLC. [http://dx.

An ac voltage-modulated thermal probe technique based on the atomic force microscope is developed to measure local Seebeck coefficients (𝑆) of thermoelectric bulk and films. The characterization principle is based on the strictly quadratic relationship between the excited local dc Seebeck voltage and the applied ac voltage at high frequency. Excellent agreement is found between local 𝑆 values and their corresponding macro-𝑆 values of thermoelectric bulk and thin films. This thermoelectric probe technique provides a very convenient, promising tool for local thermoelectric parameters with sub-micrometer scale resolution.

To improve the static performance, dynamic performance, and current balance of a current-source PWM rectifier with multi-modules, a comprehensive control method with passivity-based control and current balance control is proposed in this paper. Current balance control, which is based on AC voltage sequencing, has the advantages of being easy to implement and not being limited by the number of modules. Mathematical modelling, controller design, and simulation verification were conducted successively, and the results show that the comprehensive control method has a low current impact and high power quality. At the same time, module currents are well balanced, even under external disturbance, when using current balance control.

Pollution flashover of insulators is an important factor causing trip of transmission lines and even large-scale blackouts of power grids. At present, the research on pollution discharge of insulators mainly focuses on leakage current monitoring, while leakage current detection mainly focuses on the low-frequency components of the discharge process, and the research on high-frequency discharge characteristics is rare. In this paper, the voltage is monitored based on the coupling capacitance partial voltage method. The high-frequency current is monitored based on the Rogowski coil principle. The characteristics of high frequency pulse discharge in safety zone, forcast zone and danger zone are analyzed. The results show that the pulse amplitude and repetition rate increase significantly with the increase of discharge. The statistical law of high frequency pulse current can reflect the severity of pollution discharge and realize early warning.