Monthly Archives: February 2015

Synthesis of a novel alkali-activated magnesium slag-based nanostructural composite and its photocatalytic performance

Publication date: 15 March 2015 Source:Applied Surface Science, Volume 331 Author(s): Yao Jun Zhang , Le Kang , Li Cai Liu , Hai Xiao Si , Ji Fang Zhang A novel type of alkali-activated magnesium slag-based nanostructural composite (AMSNC) co-loaded bimetallic oxide semiconductors of NiO and CuO were synthesized by alkaline activation, ion exchange and wet co-impregnation methods, and then firstly employed as a photocatalyst for the degradation of indigo carmine dye. The XRD, TEM and HRTEM results revealed that CuO in the form of tenorite with mean particle size of about 15nm and NiO in amorphous phase dispersed on the surface of AMSNC support. The decrease of photoluminescence with increasing amount of NiO and CuO demonstrated that the recombination of photogenerated electrons–holes pairs was prevented when the photogenerated electrons transferred from the metal oxide semiconductor to the AMSNC matrix. The 10(NiO+CuO)/AMSNC specimen showed that the photocatalytic degradation efficiency was up to 100% under UV irradiation for 1h due to the synergistic effect between the AMSNC and active species of NiO and CuO. The mesoporous structures of specimens acted as critical role for the adsorption of dye molecules, and the photocatalytic degradation of indigo carmine dye obeyed first-order reaction kinetics. A degradation mechanism of photocatalytic oxidation was proposed in the paper.

Accurate power model for mobile AMOLED displays

The display is a dominant power-consuming component in mobile devices. The active matrix organic light-emitting diode (AMOLED) display has been popular in mobile devices and its accurate power model is crucial for efficient power management. Existing power models do not consider the behaviours of the driving hardware components of AMOLED display modules. A new power model is proposed which considers the efficiency of an AMOLED DC–DC converter and the dependency of the driving circuits in a commercial AMOLED display module, and thus estimates an accurate power consumption value. Through extensive experiments using three well-known image databases, the proposed power model is found to have lower error rates than the existing pixel-based one for all the databases. Especially, for bright images the error rate of the new model amounts to only 0.59%, whereas that of the existing one is 8.48%.

Nonlinear modelling of dynamic self-heating in 28 nm bulk complementary metal–oxide semiconductor technology

A new and simple approach for nonlinear modelling of the dynamic self-heating effect in bulk complementary metal–oxide semiconductor (CMOS) field effect transistors is presented. Low-frequency S-parameter measurements are performed in 28 nm bulk CMOS technology at room temperature between a 10 kHz and 3 GHz frequency range and the thermal impedance (ZTH) of the devices is extracted. The proposed model is validated through the measurements for different bias points. The results obtained demonstrate a reasonable agreement between theoretical prediction and experimental data.