The authors have investigated the impact of nanowire geometry on the carrier transport in axial indium gallium nitride and gallium nitride (InGaN/GaN) nanowire light-emitting diodes (LEDs). The results reveal that hole transport depends critically on the nanowire geometry. With identical material parameters, the carrier transport process can be varied with different nanowire geometry designs, which lead to different overall device performance. This study offers important insight into the design and epitaxial growth of high-performance nanowire LEDs.

The authors outline an approach to construct capacity-approaching balanced quadrature phase shift keyed (QPSK) codes. These codes ensure an equal number of different symbol values and many symbol transitions in the encoded sequence in order to assist practical demodulators to accurately recover symbol values. Their codes are comprised of instantaneously decodable variable-length codewords that exhibit excellent performance with average code rates higher than previously reported fixed-length balanced QPSK codes.

This study proposed an adaptive double-integral-sliding-mode-controller-maximum-power-point tracker (DISMC-MPPT) for maximum-power-point (MPP) tracking of a photovoltaic (PV) system. The objective of this study is to design a DISMC-MPPT with a new adaptive double-integral-sliding surface in order that MPP tracking is achieved with reduced chattering and steady-state error in the output voltage or current. The proposed adaptive DISMC-MPPT possesses a very simple and efficient PWM-based control structure that keeps switching frequency constant. The controller is designed considering the reaching and stability conditions to provide robustness and stability. The performance of the proposed adaptive DISMC-MPPT is verified through both MATLAB/Simulink simulation and experiment using a 0.2 kW prototype PV system. From the obtained results, it is found out that this DISMC-MPPT is found to be more efficient compared with that of Tan's and Jiao's DISMC-MPPTs.

The control effect by using the conventional method is not satisfied because of the grey character caused from time-variant parameters of hydro-generator units and its governor. The grey extra-deleting control theory is applied to the governor design of hydro-generator units in this paper. After the mathematic model of hydro-generator and its governor are founded, the grey extra-deleting controller is designed and its effect is studied compared with the conventional proportional–integral–derivative governor. The simulation results indicate that the grey extra-deleting controller can improve dynamic characteristic of hydro-generator units.

By utilising an active diode pair to substitute the classical Chua's diode, an improved third-order Chua's circuit is proposed in this study. This circuit has an unstable zero saddle point and two stable non-zero saddle-foci in a local parameter region, from which hidden dynamics and multi-stability are discovered. The parameter region of hidden dynamics is figured out and hidden attractors are captured numerically and experimentally. Furthermore, multi-stability in the proposed circuit are also exhibited by numerical and circuit simulations.