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Highly dispersed Au nanoparticles (AuNPs) with different size were synthesized successfully on the surface of reduced graphene oxide (RGO), the binary AuNPs/RGO nanocomposites with smaller size (4 nm) show higher activity for photocatalytic hydrogen production and reaches a high H2 production rate of 2.1 mmol h‐1g‐1. The detailed mechanism is discussed in the article.

The abrasive wear performance of high-strength steels was evaluated by two kinds of designed laboratory test methods, i.e. the sliding abrasion test and the stirring wear test. Optical microscopy and scanning electron microscopy were utilized to observe the worn surfaces, microstructures and inclusions. The tested results show that the feeding of a small amount (1.5 kg/t) of Ca–Mg–RE–Zr (RE, Rare Earth) composite cored wire replacing 0.31 (wt%) expensive Ni in the steels resulted in better mechanical properties and much better abrasive wear performance, which was attributed to the modification of inclusions and improvement of impact toughness by the addition of Ca–Mg–RE–Zr composite cored wire. Microcutting, microploughing and scratching were the main wear mechanisms in abrasive wear tests. The abrasive loss of high-strength steels was larger in the wet wear condition than that in the dry wear condition in the sliding abrasion test, which was caused by the increasing corrosion wear and reducing debris accumulation.

GaN-based InGaN/GaN multi-quantum-well light emitting diode (MQW LED) structures were grown by metal organic chemical vapor deposition method. The optical properties of the LED structure have been investigated by using the photoluminescence and electroluminescence measurement. Both photoluminescence and electroluminescence results indicate that near pure InN clusters exist within the InGaN layers, which are responsible for the light emission in the LED. With increasing the Mg activation temperature of p-GaN layer, the optical properties of the LED structure tended to significantly degrade. This degradation was found to be deeply related to the variation of InN clusters in the active region. By the current–voltage measurement, a large forward voltage variation was observed. The voltage variation is caused to the conductivity variation of the p-GaN layer due to the different activation temperature. The turn-on voltage obtained from the best LED was 2.56 V and the forward voltage measured at 20 mA was 3.5 V. On the basis of these results, activation of the Mg-doped p-GaN layer must be carried out at the lowest possible value so as to obtain the better performance of LEDs.